HK1098878B - Secondary battery - Google Patents

Description

Secondary battery

CROSS-REFERENCE TO RELATED APPLICATIONS

The subject matter contained in the present invention relates to Japanese patent application JP2005-234941, filed 2005-8, 12-d to the sun in the office, the entire content of which is incorporated herein by reference.

Technical Field

The present invention relates to a secondary battery having an electrode body as an electric energy generating element housed in a package (pack), and from which electric power generated by the electrode body can be output through a pair of positive and negative electrode terminals, such as a lithium ion secondary battery and a lithium polymer secondary battery.

Background

In recent years, the demand for portable electronic devices including information devices such as notebook personal computers, mobile communication devices such as mobile phones, and video cameras has been rapidly increasing. Sealed small-sized secondary batteries such as nickel-cadmium batteries, nickel-hydrogen batteries, and lithium ion batteries are often used as power sources for such electronic devices. In particular, lithium ion secondary batteries are employed in various applications, having most of the features such as high voltage, high energy density, and lightweight.

Specifically, as a countermeasure against the problem of liquid leakage occurring in a liquid-based electrolytic solution, for example, a so-called polymer lithium ion secondary battery using, as an electrolyte, a gel-like polymer film having a polymer impregnated with a nonaqueous electrolytic solution, or using an all-solid-state electrolyte,

such polymer lithium ion secondary batteries are being further developed to meet the requirements of various electronic devices in recent years, such as miniaturization, weight reduction, and slimness, and have a feature of high freedom in the shape of the battery in addition to the battery features such as high energy density and light weight.

Patent document 1: JP-A-2002-8606-

Disclosure of Invention

According to an embodiment of the present invention, there is provided a secondary battery that has many advantages of a secondary battery represented by a polymer lithium ion secondary battery and can appropriately meet the requirements of electronic devices in recent years, such as miniaturization, weight reduction, and slimness.

In order to solve the above-described problems, according to an embodiment of the present invention, there is provided a secondary battery for an electronic apparatus, which is accommodated in the electronic apparatus and thus can supply power to the electronic apparatus. The secondary battery is provided with: a battery cell in which a positive electrode, a negative electrode, and an electrolyte are contained in a package, and a positive electrode terminal and a negative electrode terminal from the positive electrode and the negative electrode are respectively drawn from the same side of the package; a metal battery case in which an opening into which the battery cell is inserted and which accommodates the battery cell therein is formed such that one side face from which the positive electrode terminal and the negative electrode terminal are drawn out faces the opening side; and a cover made of synthetic resin, wherein, once the positive electrode terminal part and the negative electrode terminal part are connected to the positive electrode terminal and the negative electrode terminal and face to the outside, the positive electrode terminal part and the negative electrode terminal part to be connected to the electrode of the electronic device are set, and the opening of the battery case is plugged with the cover. The battery cell is accommodated in the battery case after being attached to the inner surface of the battery case while the positive and negative electrode terminals are bent between the positive and negative electrode terminals and the cover.

According to the secondary battery of the embodiment of the invention, by configuring the battery main body using the metal battery case, it is possible to achieve slimness and ensure mechanical strength. Moreover, since the engaging portion connected to the lid, on which the positive electrode terminal and the negative electrode terminal and the positive electrode terminal portion and the negative electrode terminal portion are formed, are accommodated in the battery case while being bent, even when an impact due to dropping or vibration of the secondary battery or the like acts between the battery cell and the lid, the engaging portion, which has been bent and accommodated, can absorb the impact load, so that it is possible to prevent occurrence of separation between the positive electrode terminal and the positive electrode terminal portion and between the negative electrode terminal and the negative electrode terminal portion.

Drawings

FIG. 1 is an oblique view showing an example of an electronic apparatus using a secondary battery of the invention;

fig. 2 is an oblique view showing a secondary battery to which the present invention is applied;

fig. 3 is a detailed oblique view showing a secondary battery to which the present invention is applied;

fig. 4 is an oblique view showing a state in which a secondary battery to which the present invention is applied is mounted in a battery housing part of an electronic apparatus;

fig. 5 is an oblique view showing another example of a secondary battery to which the present invention is applied;

fig. 6 is a side view showing a state in which a secondary battery to which the present invention is applied is mounted in a battery mounting portion provided externally of an electronic apparatus or the like;

fig. 7 is an oblique view of a battery case into which the battery cell is inserted;

fig. 8 is a side view showing a state in which an electrode portion is provided in a joint of a battery mounting portion provided outside an electronic apparatus or the like;

fig. 9 is a view showing a secondary battery to which an external label is attached, in which fig. 9A is a rear view, fig. 9B is a plan view, and fig. 9C is a front view;

fig. 10 is a cross-sectional view of the secondary battery showing the assembled state of the battery cover;

fig. 11 is a detailed oblique view showing a battery cell;

fig. 12 is a cross-sectional view showing a battery cell package structure;

FIG. 13 is a side view showing the junction between the positive or negative electrode terminal and the positive or negative electrode tab of the battery cell;

fig. 14 is a side view showing a junction between the positive or negative electrode terminal and the positive or negative electrode sheet;

fig. 15 is an oblique view showing a secondary battery in which the arrangement of positive and negative electrode terminal portions is different depending on the function;

fig. 16 is an oblique view showing another secondary battery in which the arrangement of the positive and negative electrode terminal portions is different depending on the function;

fig. 17 is an oblique view showing another example of a secondary battery to which the present invention is applied;

fig. 18 is a process flow chart showing a manufacturing process of a secondary battery to which the present invention is applied;

fig. 19 is a side view showing the battery cell, the holder, and the substrate placed in the jig;

fig. 20 is an oblique view showing the battery cell inserted into the battery case;

fig. 21 is a cross-sectional view showing the state of the battery cell inside the battery case;

fig. 22 is a cross-sectional view showing a state in which a battery cell is adhered to the inside of a battery case using an adhesive;

fig. 23 is a cross-sectional view showing the state of a battery cell adhered to the inside of a battery case by an adhesive;

fig. 24 is an oblique view showing another example of a secondary battery to which the present invention is applied;

fig. 25 is an oblique view showing a battery laminate;

fig. 26 is an oblique view showing a battery assembly;

fig. 27 is an oblique view showing a secondary battery to which the present invention is applied;

fig. 28 is an oblique view showing a battery assembly in which the stacking width is folded;

fig. 29 is a front view showing a substrate to which positive and negative electrode terminals led out from a battery laminate are soldered;

fig. 30 is an oblique view showing a battery charger for a secondary battery to which the present invention is applied;

fig. 31 is a front view showing a secondary battery mounted in the above-described battery charger;

fig. 32 is an oblique view showing another example of a battery charger for a secondary battery to which the present invention is applied;

fig. 33 is a cross-sectional view showing the above-described battery charger mounted with a secondary battery;

fig. 34 is an oblique view showing the above-described battery charger accommodating the holding arm;

fig. 35 is an oblique view showing another example of a battery charger for a secondary battery to which the present invention is applied;

fig. 36 is an oblique view showing the above-described battery charger mounted with a secondary battery;

fig. 37 is an oblique view showing a related art polymer lithium ion secondary battery.

Detailed Description

Hereinafter, a secondary battery to which the present invention is applied will be described in detail with reference to the accompanying drawings. The secondary battery 1 to which the present invention is applied is, for example, a polymer lithium ion secondary battery, and, as shown in fig. 1A and 1B, can be used for various electronic devices such as a digital camera 10. Specifically, when the secondary battery 1 is accommodated in a battery accommodating portion 12 provided inside a grip portion 11 of the digital camera 10 as shown in fig. 1A, the secondary battery 1 supplies driving power to this digital camera 10. The battery housing portion 12 is constituted by a substantially planar concave portion corresponding to the shape of the secondary battery 1, and the battery housing portion 12 is directed outward when a battery cover 14 rotatably provided on a bottom surface portion 13 of the digital camera 10 is opened. Further, in the battery housing portion 12, a housing portion electrode is formed at the bottom, which is in contact with electrode terminal portions 37, 38 provided on the secondary battery 1 (described later). Also, when the secondary battery 1 is housed in the battery housing portion 12 with the end face provided with the electrode terminal portions 37, 38 being the insertion end, the secondary battery 1 is connected to the housing portion electrode, thereby supplying electric power to the digital camera 10. Incidentally, the battery housing portion 12 is provided with an energizing member (not shown) for releasing the secondary battery 1 from the battery housing portion 12, and an engaging member 19 for engaging the secondary battery 1 in the battery housing portion 12 in a manner opposite to the energizing member. The engaging piece 19 will be described later.

The secondary battery 1 will be described below. As shown in fig. 2 and 3, a battery cell 3 having electrode terminals enclosed therein is inserted from an opening of a metal battery case 2 formed in a substantially planar form, the opening of the metal battery case 2 being closed by a battery cover 4 provided thereon with a terminal part to which a positive electrode terminal and a negative electrode terminal led out from the battery cell 3 are connected, thus forming the secondary battery 1.

The battery case 2 is made of a metal case in which one face of a substantially flat cuboid is open while its cross section is formed in a substantially trapezoidal shape such that the edge of each of the short sides is formed in a circular arc shape, as shown in fig. 3. The battery case 2 is formed into a substantially flat cuboid in which an opening 5 for inserting the battery cell 3 is formed on only one face, which is molded by drawing (deep drawing) a metal material such as iron. The battery case 2 is formed in an elongated shape by adjusting the wall thickness to about 0.3mm, so that the thickness itself can be controlled to the maximum when the accommodation area of the battery cell 3 is not considered; meanwhile, by using a metal material, the battery case 2 may have various impact resistances against dropping, vibration, etc., or mechanical strength against sharp edges, etc., so that occurrence of deformation, perforation, etc. may be prevented. The opening 5 is an insertion end from which the battery cell 3 is inserted, and after the battery cell 3 is inserted, the opening 5 is closed by the battery cover 4. For this, a plurality of engaging holes 6 are perforated on the outer circumference of the opening 5, which are engaged with protrusions 47 protruding from the battery cover 4. In the engaging hole 6, when the battery cover 4 is inserted into the opening 5, the engaging protrusion 47 protruding on the battery cover 4 is pushed into the opening 5 while being bent, and then is engaged with the engaging hole 6. Thus, the battery cover 4 is fitted to the battery case 2.

When the shape of the battery housing 12 (into which the secondary battery 1 is inserted together with the battery case 2) is formed in a substantially trapezoidal shape in cross section such that the edge of each of the short sides is formed in a circular arc shape as shown in fig. 4A, the insertion face of the secondary battery 1 into the battery housing 12 of the digital camera 10 is defined, so that erroneous insertion can be prevented. That is, as shown in fig. 4A, when the insertion surface of the secondary battery 1 is correct, the shape of the side surface on the short side of the battery housing portion 12 matches the shape of the main surface of the side surface on the short side of the secondary battery 1, and the secondary battery 1 can be inserted smoothly. On the other hand, as shown in fig. 4B, when the insertion face of the secondary battery 1 is inserted reversely, the square edge in the side face on the long side of the secondary battery 1 is interfered by the arc-shaped edge in the side face on the short side of the battery housing part 12, thereby preventing the secondary battery 1 from being inserted. Thus, when the insertion face is inserted backward and forward, not only the secondary battery 1 can be prevented from being inserted into the battery housing part 12, but also the user can easily confirm the correctness of the insertion face of the secondary battery 1.

Incidentally, when the secondary battery 1 is externally attached to a battery mounting portion formed on the case of the electronic device (separately from the battery housing portion 12 in the bottom surface portion 7 opposite to the opening 5) or mounted in a battery mounting portion of the battery charger 80 as shown in fig. 5A and 5B, the battery case 2 may be formed with an engagement hole 8 that engages with an engagement piece 9 protruding in the battery mounting portion of the electronic device or the battery charger as shown in fig. 6. As shown in fig. 7, since a concave portion 29 (described later) is formed on the insertion end face 3b of the battery cell 3, when the engagement hole 8 corresponding to the concave portion 29 is formed, it is formed so as not to affect the battery element 20 provided with the positive electrode, the negative electrode, and the electrolyte accommodated inside the battery cell 3.

Incidentally, the view of fig. 5A shows an example in which the engaging holes 8 are formed over the entire length in the longitudinal direction of the bottom face portion 7; in this case, in the battery case 2, the first curling (winding) portion 17 is not provided on the external label 15 described below, and the bottom face portion 7 is exposed outward over the entire length. Further, the view of fig. 5B shows an example in which a pair of engaging holes 8, 8 are formed on both end portions in the longitudinal direction of the bottom face portion 7; in this case, a first curl portion 17 for sticking an area other than both end portions where the engagement holes 8, 8 are formed is provided on the external label 15.

Further, as shown in fig. 6, when the secondary battery 1 is engaged with the engaging member 9 that is rotationally driven in the engaging direction of the battery case 2, the secondary battery 1 can be externally attached to the outside of the case of the electronic apparatus or the like. Thus, in addition to the secondary battery 1 accommodated in the battery accommodating portion, the independent secondary battery 1 can be easily externally attached to the electronic apparatus, and therefore, the use time of the electronic apparatus can be prolonged.

The engaging hole 8 is not limited to the example shown in fig. 5A and 5B, and may be formed in any shape as appropriate. Also, an engaging recess may be provided in the battery mounting portion, and thus an engaging protrusion having a shape corresponding to the engaging recess on the bottom surface portion 7 of the battery case 2 may be formed.

Incidentally, with the secondary battery 1 to which the present invention is applied, in addition to the embodiment in which the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are formed and the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are directed to the outside (described below) from the terminal hole 48 formed on the front surface 1c, an embodiment may be adopted in which not only the positive electrode terminal portion 37 is formed on the substrate 35 but also the engagement hole 8 formed on the bottom surface portion of the metal battery case 2 is used as a negative electrode or a ground electrode. In this case, as shown in fig. 8A, a case bottom electrode 57, which becomes a negative electrode or a ground electrode, is provided at a position for forming the engagement hole 8 on the bottom surface portion 7 of the battery case 2, and faces outward through the engagement hole 8. On this case bottom electrode 57, a negative electrode wire or a ground wire connected to the substrate 35 is surrounded and connected. Further, in the engaging piece 9 engaged with the engaging hole 8, an electrode portion 9a connected to an electrode or an electronic device-side grounding member is formed and connected to the case bottom electrode 57 at the time of engagement with the engaging hole 8 of the secondary battery 1.

Further, in the battery case 2, after the battery cover 4 is attached, the battery unit 3 is inserted, and the opening 5 is closed by the battery cover 4, and the insulating outer label 15 is stuck. The external label 15 becomes a decorative label of the secondary battery 1 and can also be designed to realize insulation of the metal battery case 2. As shown in fig. 3, the external label is provided with: a main surface portion 16 for curling the outer peripheral edge of the battery case 2 above the opening 5 and the bottom surface portion 7; a first curled portion 17 for curling a region other than both end portions in the longitudinal direction of the bottom surface portion 7; and a second crimping portion 18 for crimping an area other than the terminal hole 48 formed on the top cover 36 of the battery cover 4.

In the external label 15, since the battery case 2 is formed in a planar shape, the pasting work is easy, and the external label 15 is less likely to be separated than in the case of directly pasting it on the surface of the battery unit 3 configured to enclose the battery element 20. The first curled portion 17 curled on the bottom surface portion 7 of the battery case 2 is formed to be shorter than the bottom surface portion 7 in length and is stuck on the bottom surface portion 7 so that both end portions 7a, 7b in the longitudinal direction of the bottom surface portion 7 are exposed to the outside. In the battery case 2, an end portion of the bottom surface portion 7 is formed as an engaging portion that engages with an engaging piece 19 provided on the battery housing portion 12 of the digital camera 10. That is, as shown in fig. 9A and 9B, the secondary battery 1 is formed as an engagement region with which a hook-shaped engaging piece 19 for holding the battery case 2 in the battery housing part 12 of the digital camera 10 is engaged. Therefore, in the process of mounting the secondary battery 1, the engaging member 19 is engaged. In this way, the secondary battery 1, which is always driven to the outside of the battery housing portion by the driver, is engaged with the battery housing portion 12 in the direction opposite to the driving force. Further, when the engaging piece 19 is separated from the bottom face portion 7 of the engaging piece 19, the secondary battery 1 is released from the battery housing portion 12.

Here, if the first curling portion 17 of the external label 15 is completely stuck to the bottom surface part 7, the engaging piece 19 rubs the first curling portion 17 every time the secondary battery 1 is inserted into the battery housing part 12 and every time it is detached from the battery housing part 12, and thus the external label 15 is gradually rubbed and separated. In this case, since the external label 15 is curled over the region other than the engaging portion with the engaging piece 19, the secondary battery 1 is not rubbed by the engaging piece 19 even when the secondary battery 1 is repeatedly inserted into and removed from the battery housing portion 12.

Further, in the secondary battery 1, the region of the bottom surface portion 7 to which the first curl portion 17 is pasted corresponds to the region where the electrode terminal portions 37, 38 of the battery cover 4 are formed. Therefore, even when the secondary battery 1 is mounted in the battery housing part 12 or the battery charger 80 in the direction opposite to the insertion direction, the insulating external label 15 pasted on the bottom surface part 7 of the battery case 2 is brought into contact with the housing part electrode provided on the bottom surface part of the battery housing part 12 corresponding to the electrode terminal parts 37, 38 or the electrode terminal of the battery charger 80, and therefore, the risk of short circuit due to direct contact with the metal battery case 2 can be avoided.

In addition, as shown in fig. 9C, once the second curled portion 18 is curled onto the region other than the terminal hole 48 formed on the top cover 36 of the battery cover 4, the second curled portion 18 of the external label 15 can reinforce the assembling strength between the battery cover 4 and the battery case 2. When the second curled portion 18 reinforces the fitting strength between the battery cover 4 and the battery case 2, as shown in fig. 10, by making the engaging depth between the engaging projection 47 provided on the top cover 36 of the battery cover 4 and the engaging hole 6 provided on the peripheral edge of the opening 5 of the battery case 2 to be engaged with the engaging projection 47 large (as described later), and making the engaging projection 47 on the upper face of the battery case 2 project from the engaging hole 6, it is not necessary to reinforce the fitting strength between the battery case 2 and the battery cover 4. Therefore, a desired assembling strength can be obtained without affecting the flatness or appearance of the secondary battery 1.

Incidentally, an information label 49 on which various kinds of information of the secondary battery 1 are described is pasted on the main face portion of the long-side face of the battery case 2.

The battery unit 3 accommodated in the battery case 2 will be described below. As shown in fig. 3 and 11, in the battery cell 3, a band-shaped positive electrode and a band-shaped negative electrode are stacked through a polymer electrolyte layer and/or a separator; the battery element 20 wound in the longitudinal direction is housed in the package member 23; the positive electrode terminal 21 and the negative electrode terminal 22 are respectively led out from the positive electrode and the negative electrode.

In the positive electrode, a positive electrode active material layer is formed on a strip-shaped positive electrode collector, and a polymer electrolyte layer is further formed on the positive electrode active material layer. Further, in the negative electrode, a negative electrode active material layer is formed on a strip-shaped negative electrode current collector, and a polymer electrolyte layer is further formed on the negative electrode active material layer. The positive electrode terminal 21 and the negative electrode terminal 22 are welded to the positive electrode collector and the negative electrode collector, respectively. Also, the positive electrode terminal 21 is made of aluminum (Al), and the negative electrode terminal 22 is made of nickel (Ni). These positive electrode terminal 21 and negative electrode terminal 22 are connected to a positive electrode tab 31 and a negative electrode tab 32 fixed on the battery lid 4, respectively, as described below, and are connected to a positive electrode terminal plate 33 and a negative electrode terminal plate 34 similarly provided on the battery lid 4 via the positive electrode tab 31 and the negative electrode tab 32, respectively.

The positive electrode may be configured using a metal oxide, a metal sulfide, or a specific polymer as a positive electrode active material according to the kind of the target battery. For example, in the construction of a lithium ion battery, a lithium ion battery containing Li as a main component may be used_xMO₂(wherein M represents one or more transition metals; and x varies depending on the charge/discharge state of the battery, and is usually 0.05 to 1.10) as a positive electrode active material. As the transition metal M constituting the lithium composite oxide, Co, Ni, Mn, and the like are preferable. Specific examples of such lithium composite oxides include LiCoO₂、LiNiO₂、LiNi_yCo_1-yO₂(wherein 0 < y < 1), and LiMn₂O₄. Such a lithium composite oxide is capable of generating a high voltage and becomes a positive electrode active material excellent in energy density. In addition, such as TiS₂、MoS₂、NbSe₂And V₂O₅The lithium-free metal sulfide or oxide of (a) may also be used as the positive electrode active material. A combination of a plurality of these positive electrode active materials may also be used. Also, in forming a positive electrode using such a positive electrode active material, a known conductive agent, a binder, or the like may be added.

Materials capable of incorporating (dedoping) or extracting (dedoping) lithium may be used as the negative electrode material. For example, inexpensive graphitized carbon-based materials or carbon materials based on graphite can be used. More specifically, carbon materials such as pyrolytic carbon, coke (e.g., pitch coke, needle coke, and petroleum coke), graphite, glassy carbon, an organic polymer composite fired body (a material formed by firing a phenol resin, a furan resin, or the like at an appropriate temperature for carbonization), carbonized fibers, and activated carbon can be used. Furthermore, polymers such as polyacetylene and polypyrrole and polymers such as SnO₂Oxides such as these can be used as a material capable of incorporating or extracting lithium. In therebyIn the formation of the negative electrode from the material-like material, a known binder or the like may be added.

The polymer electrolyte is prepared by mixing a polymer material, an electrolytic solution, and an electrolytic salt and mixing a gel electrolyte in a polymer. The polymer material has properties that make it compatible with the electrolytic solution. Examples thereof include silica gel, acrylic gel, acrylonitrile gel, polyphosphazene-modified polymer, polyethylene oxide, and polypropylene oxide, and composite polymers, crosslinked polymers, or modified polymers thereof; and fluorine-based polymers such as polyethylene (vinylidene fluoride), polyethylene (vinylidene fluoride-carbon monoxide-propylene tetrafluoride), polyethylene (vinylidene fluoride-carbon monoxide-propylene trifluoride), and the like, and mixtures thereof.

The electrolytic solution composition includes an aprotic solvent, which can disperse therein the above-described polymer materials, for example, Ethylene Carbonate (EC), Propylene Carbonate (PC), and Butylene Carbonate (BC). As the electrolytic salt, a substance compatible with the solvent may be used, and a combination of cation and anion may be used. Examples of cations that may be used include alkali metals and alkaline earth metals. Examples of anions that may be used include Cl^-、Br^-、I^-、SCN^-、ClO₄ ^- 、BF₄ ^-、PF₆ ^-And CF₃SO₃ ^-. Specifically, lithium hexafluorophosphate or lithium tetrafluorophosphate may be used as the concentrated electrolytic salt, and thus may be dissolved in the electrolytic solution.

As shown in fig. 11, the package 23 in which the battery elements 20 are housed is formed by cutting a battery assembly (aggregate)27, the battery assembly 27 having a substantially rectangular housing piece 24 and a sealing piece 26, a plurality of housing concave portions 25 for housing the battery elements 20 therein are provided in advance on the housing piece 24, the sealing piece 26 is welded to the housing piece 24 in which the battery elements 20 are housed, and the sealing piece 26 can seal each of the housing concave portions 25 for each of the battery elements 20.

The receiving sheet 24 is formed in a lengthwise shape, so that a plurality of receiving recesses 25 can be provided by a stacking width 28 having a predetermined width. The accommodation recess 25 is formed in a substantially rectangular shape according to the shape of the battery element 20. Further, the arrangement direction of the accommodating recessed portions 25 is not limited to the short side direction shown in fig. 11, and the accommodating recessed portions 25 may be provided in the long side direction or in the longitudinal and diagonal directions. The stacking width 28 that separates the respective accommodation recesses 25 is an engagement surface of the sealing sheet 26 for sealing the accommodation recesses 25. Further, as shown by an arrow a in fig. 11, when the battery element 20 is accommodated in each of the accommodation recesses 25, the sealing sheet 26 is thermally welded to the stacking width 28, thereby forming a battery assembly 27 having the battery element 20 integrated therein.

Incidentally, at this time, the positive electrode terminal and the negative electrode terminal extending from the positive electrode and the negative electrode are drawn out in the same direction from the joint portion with the sealing sheet 26. Further, at this time, vacuum evacuation is performed while welding with a vacuum pump (not shown). Due to this suction force, the battery element 20 is sealed in the accommodation recess 25 covered with the accommodation sheet 24 and the sealing sheet 26. Also, by sucking the inside of the accommodation recess 25, the package 23 for accommodating the battery element 20 therein is pulled and pressed, thereby forming a shape whose cross section is substantially trapezoidal such that the edge of each of the short sides is formed into a circular arc shape in which the second face side as the bottom face side of the accommodation recess 25 is small and the second face side as the opening side is large in accordance with the shape of the battery element 20.

Further, in the battery unit 3, a gap is provided between the battery element 20 and the housing piece 24 in such a manner that the battery element 20 is not pressed against the side surface of the housing recess 25. Further, when the housing sheet 24 and the sealing sheet 26 are sealed while being pulled and pressed, a concave portion 25 is formed on the face on the opposite side of the battery cell 3 from which the positive electrode terminal 21 and the negative electrode terminal 22 are drawn (see fig. 7). Further, after the housing sheet 24 and the sealing sheet 26 are sealed, in each battery cell 3, the main surface on the sealing sheet 26 side is formed into a flat shape by pressing. Thereafter, the battery assembly 27 is cut along the stacking width 28 and each package 23 having the battery element 20 sealed therein is separated, thereby forming the battery unit 3.

Incidentally, in addition to forming the battery cells 3 by forming the battery assembly 27 and cutting the battery assembly 27 along the stacking width 28, the battery element 20 may be housed on a previously cut housing sheet for each individual battery cell, and then joined with a sealing sheet for the individual battery cell obtained by similar cutting to form the battery cells 3.

Each of the containing sheet 24 and the sealing sheet 26 constituting the package 23 has a stacked structure in which a polypropylene (PP) layer 52, an aluminum (Al) layer 53, and a nylon layer 54 are stacked in order from the inside, as shown in fig. 12. Here, the aluminum layer 53 serves the purpose of preventing moisture from intruding into the package member 23 and preventing the battery element 20 from swelling. Further, the polypropylene layer 52 not only prevents the polymer electrolyte from being denatured, but also serves as a bonding surface between the holding sheet 24 and the sealing sheet 26. That is, the joining between the containment sheet 24 and the sealing sheet 26 is achieved by opposing the polypropylene layers 52 to each other and heating them to melt at about 170 ℃.

Incidentally, the structure of the package 23 is not limited to this, and a laminate film, a stacked structure, or the like having various materials may also be employed. The joining method is not limited to heating and melting. Examples of the constituent material of the package 23 include aluminum, polyethylene terephthalate (PET), non-axially-stretched polypropylene (CPP), acid-modified polypropylene, ionomer, and ON.

A battery cover 4 having terminal portions connected to a positive electrode terminal 21 and a negative electrode terminal 22 drawn from the same side of the battery cell 3 and closing the opening 5 of the battery case 2 is provided with: a holder 30 for inserting and holding a positive electrode tab 31 and a negative electrode tab 32 connected to the positive electrode terminal 21 and the negative electrode terminal 22, respectively; a substrate 35 provided with a positive electrode terminal plate 33 and a negative electrode terminal plate 34 connected to the positive electrode tab 31 and the negative electrode tab 32, respectively; and a top cover 36 which sandwiches the base plate 35 together with the holder 30 and engages with the opening 5 of the battery case 2, and the battery cover 4 is manufactured by integrally assembling the holder 30, the base plate 35 and the top cover 36, as shown in fig. 3.

The holder 30 is a member formed in a substantially trapezoidal flat plate shape such that the edge of each of the short sides is formed in a circular arc shape, which is made by molding synthetic resin into the same shape as the opening 5 of the battery case 2. In the holder 30, a pair of insertion holes 41, 42 through which the positive electrode sheet 31 and the negative electrode sheet 32 are inserted are formed in the vicinity of the side faces on the short side, respectively, and by inserting and holding the positive electrode sheet 31 and the negative electrode sheet 32 in the insertion holes 41, 42, respectively, it is possible to design so as to position the positive electrode sheet 31 and the negative electrode sheet 32 and prevent the secondary battery 1 from dropping or positional deviation caused by vibration or the like. Therefore, the positive electrode tab 31 and the negative electrode tab 32 can prevent a situation where welding is performed between the positive electrode terminal 21 and the negative electrode terminal 22 due to dropping or positional deviation caused by vibration or the like.

The purpose of providing the positive electrode tab 31 and the negative electrode tab 32 is to connect the positive electrode terminal 21 and the negative electrode terminal 22 drawn from the battery cell 3 to the positive electrode terminal plate 33 and the negative electrode terminal plate 34 provided on the substrate 35, wherein the substrate 35 becomes an electrode terminal of the secondary battery 1, and when the positive electrode tab 31 and the negative electrode tab 32 are inserted and supported in the holder 30, one ends 31a, 32a extend to the battery cell 3 side, and the other ends 31b, 32b extend and are held on the substrate 35 side. In these positive and negative electrode sheets 31 and 32, one ends 31a, 32a are provided on the positive and negative electrode terminals 21 and 22, respectively, and the other ends 31b, 32b are provided on the positive and negative electrode terminal plates 33 and 34 provided on the substrate 35, respectively, by using nickel (Ni), and then the four points are collectively welded together by spot welding. The reason for this is that, since the positive electrode terminal 21 is formed of aluminum (Al), if the positive electrode terminal 21 is directly welded to the positive electrode terminal plate 33, the aluminum is melted and the connection cannot be completed. Therefore, by adjusting the positive electrode tab 31 and the negative electrode tab 32 and performing welding from the upper side, the positive electrode terminal 21 is connected to the positive electrode terminal plate 33, and the negative electrode terminal 22 is connected to the negative electrode terminal plate 34.

Further, as shown in fig. 13A and 13B, on the respective one ends 31a, 32a of the positive and negative electrode sheets 31, 32, there are formed folded portions 39, 40 whose tip edges are folded toward the side opposite to the contact surface with the electrode terminal 21 and the negative electrode terminal 22. In the folded portions 39, 40, as shown in fig. 14, the positive electrode sheet 31 and the negative electrode sheet 32 each have a thickness of 0.1mm, and the tip thereof is folded to a height of about 0.3 mm. Thus, by folding the tip side, the positive electrode tab 31 and the negative electrode tab 32 are each made to be placed vertically in a circular arc shape and to be engaged with the positive electrode terminal 21 and the negative electrode terminal 22, respectively, as described later. Thereafter, when the joint 50 is folded, even when the tip comes into contact with the positive electrode terminal 21 or the negative electrode terminal 22, it is possible to prevent the occurrence of a situation in which the positive electrode terminal 21 or the negative electrode terminal 22 is damaged or cut.

Incidentally, a ground wire 43 for discharging the electric charge charged on the battery case 2 is connected to the negative electrode tab 32. When the ground wire 43 is supported by the holder 30, one end thereof may be connected to the negative electrode tab 32, and the other end may be in contact with the inner surface of the battery case 2. In this way, even when the metal battery case 2 is charged with electric charge, the electric charge can be discharged to the negative electrode tab 32 through the ground wire 43, and thus, it is impossible to cause erroneous operation of the microcomputer inside the secondary battery 1 or the electronic device in which the secondary battery 1 is mounted due to the electric charge charged in the secondary battery 2. Incidentally, a ground line may be connected to the substrate 35, thereby releasing electric charges onto the negative electrode sheet 32 through the substrate 35.

Further, a plurality of coupling projections 44 inserted into and engaged with coupling holes 46 provided in the top cover 36 are formed intermittently in the longitudinal direction on the upper and lower surfaces 30a, 30b of the holder 30. When the coupling projections 44 are engaged with the coupling holes 46, the holder 30 is coupled with the top cover 36, thereby sandwiching the substrate 35.

The substrate 35 is a rigid substrate on which a circuit pattern for supplying an electric current from the battery unit 3 to the electronic equipment through the terminal plates 33, 34 is formed, and the substrate 35 is mounted with a positive electrode terminal plate 33 and a negative electrode terminal plate 34, the positive electrode terminal plate 33 and the negative electrode terminal plate 34 being welded to the other ends 31b, 32b of the positive electrode tab 31 and the negative electrode tab 32, respectively. The positive electrode terminal plate 33 and the negative electrode terminal plate 34 are connected to a positive electrode terminal portion 37 and a negative electrode terminal portion 38 formed on one face on the opposite side to the mounting face, respectively. Further, on the substrate 35, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are directed outward through the terminal hole 48 provided on the top cover 36, and are brought into contact with the electrode terminals provided on the side of the digital camera 10 or the battery charger 80.

The positive electrode terminal portion 37 and the negative electrode terminal portion 38 are formed in different arrangements from each other according to the function of the secondary battery 1. The reason for this is as follows: in the secondary battery 1 used for various electronic devices, there is a case where, although the external shape is the same for the battery case 2 or the battery cover 4, plural types of secondary batteries 1 which are incompatible with each other can be provided by making the battery capacity different depending on the electronic device used, or by making compatible electronic devices different. Further, there is also a case where a plurality of secondary batteries 1 different in function from each other are provided, such as a combination of two types, one of which is provided with a remaining battery life display section such as an LED display section or a liquid crystal display section and a remaining battery life display button to introduce a remaining battery life display function, and the other of which is not provided with such a remaining battery life display function; and another two types of combinations, wherein one type is capable of quick recharging and the other type is incapable of quick recharging.

However, since the outer shapes of all types of secondary batteries 1 having any functions are the same, it is possible to mount the secondary batteries 1 on incompatible electronic devices. Then, by making the arrangement of the positive electrode terminal portion 37 and the negative electrode terminal portion 38 different for each function, and similarly by making the arrangement of the electrode terminals of the compatible electronic device different, any trouble due to erroneous mounting of the secondary battery can be avoided.

Specifically, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 for each function are disposed at substantially point-symmetrical positions. For example, in the secondary battery 1A having a battery capacity of 760mAh shown in fig. 15A and the secondary battery 1B having a high battery capacity of 830mAh shown in fig. 15B, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are disposed in substantially point-symmetrical positions as if rotated by 180 degrees. Incidentally, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 for each function may also be provided at left-right symmetrical positions as shown in fig. 16A and 16B. Further, the arrangement shape substantially point-symmetrical may be appropriately selected.

In this way, by making the arrangement of the positive electrode terminal portion 37 and the negative electrode terminal portion 38 different according to the function of the secondary battery 1 and making the arrangement of the electrode terminals of the electronic device corresponding to the function different, even when the secondary battery 1 is mounted on an incompatible electronic device, since the electrode terminals of the side of the electronic device do not come into contact with the electrode terminals of the side of the secondary battery 1, it is possible to prevent any trouble due to erroneous mounting of the incompatible secondary battery 1.

On the substrate 35, a circuit pattern and a land (land) are formed by etching with a copper foil or the like pasted on an insulating substrate, and the positive electrode terminal plate 33 and the negative electrode terminal plate 34 are mounted on the land by reflow soldering. As described above, the positive electrode terminal plate 33 and the negative electrode terminal plate 34 are soldered to the positive electrode tab 31 and the negative electrode tab 32, respectively, together with the positive electrode terminal 21 and the negative electrode terminal 22, respectively. Also, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are formed on the lands formed at predetermined positions by gold plating (gilding) or the like.

Incidentally, if desired, the substrate 35 may be provided with a heat-sensitive element such as a PTC (positive temperature coefficient) for detecting the temperature of the secondary battery 1 to achieve charge control or safety control. By providing the heat sensitive element, the secondary battery 1 can cut off and control the input/output circuit when the temperature rises.

The top cover 36, which sandwiches the base plate 35 together with the holder 30, is a substantially trapezoidal flat plate-like member, so that the edge of each of the short sides can be formed into a circular arc shape, which is made by molding synthetic resin into substantially the same shape as the opening 5 of the battery case 2, and can be tightly engaged with the opening 5. In the top cover 36, a plurality of coupling holes 46 are intermittently formed corresponding to the coupling protrusions 44 on the upper face 36a of the short side face and the lower face 36b of the long side face, wherein the plurality of coupling protrusions 44 protruding on the holder 30 are inserted and engaged in the coupling holes 46. Further, in the top cover 36, on the upper face 36a and the lower face 36b, a plurality of engaging projections 47 are formed which engage with engaging holes 6 formed on the peripheral edge of the opening 5 of the battery case 2. Also, when the top cover 36 is inserted into the battery case 2 from the opening 5 in such a manner that the upper face 36a and the lower face 36b are slightly bent, the engaging projections 47 engage with the engaging holes 6 and are fitted into the battery case 2.

Further, on the top cover 36, a terminal hole 48 is pierced on the front face 36c, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 formed on the substrate 35 are directed outward from the terminal hole 48, and further, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are brought into contact with an electrode terminal on the side of an electronic device such as the digital camera 10 or a battery charger 80 through the terminal hole 48. Incidentally, the terminal holes 48 are provided at three positions in accordance with terminal portions formed on the substrate 35, for example, and may be provided to operate for a positive electrode terminal and a negative electrode terminal, and to operate for a terminal of information such as remaining battery life, respectively. Incidentally, the number of the terminal holes 48 may be increased or decreased as appropriate depending on the terminal portions provided on the substrate 35.

When the positive electrode terminal 21 and the negative electrode terminal 22 of the battery unit 3 are connected to the positive electrode terminal plate 33 and the negative electrode terminal plate 34 on the substrate 35, respectively, through the positive electrode tab 31 and the negative electrode tab 32 held on the holder 30, and the connecting projection 44 of the holder 30 is inserted into the connecting hole 46, the top cover 36 and the holder 30 are connected while sandwiching the substrate 35 therebetween, thereby forming the battery cover 4. Thereafter, when the engaging projection 47 of the top cover 36 is engaged with the engaging hole 6 formed on the peripheral edge of the opening 5 of the battery case 2, the battery cover 4 is fitted to the battery case 2, thereby forming the secondary battery 1.

Incidentally, on the top cover 36, as shown in fig. 17A, 17B and 17C, when the top cover 36 is externally attached to a battery mounting portion formed on an electronic apparatus case separate from the battery housing portion 12 on the front face 36C, or when the top cover 36 is mounted on a battery mounting portion of a battery charger 80, an engaging portion 79 may be formed which is engaged with an engaging projection 78 protruding on the battery mounting portion of the electronic apparatus or the battery charger. In the secondary battery 1, as shown in fig. 6, the battery case 2 is mounted while the engaging portion 79 is engaged with the engaging projection 78. The engaging portion 79 can be easily formed when the top cover 36 is molded. Incidentally, fig. 17A shows an example in which engaging portions 79 are formed in the form of recesses at both ends of the front face 36c of the top cover 36; fig. 17B shows an example in which both ends of the engaging portion 79 in the form of a recess are notched; and fig. 17C shows an example in which an engaging recess is provided on the battery mounting portion, and a protruding engaging portion 79 having a shape corresponding to the engaging recess is formed on the top cover 36 of the secondary battery 1.

Incidentally, in the present specification, with respect to the secondary battery, the main surface in the short side surface of the battery case 2 refers to the upper surface 1a of the secondary battery 1; the principal surface of the long side surface of the battery case 2 is the lower surface 1b of the secondary battery 1; the front face 36c of the top cover 36 refers to the front face 1c of the secondary battery 1; and the bottom surface portion 7 of the battery case 2 refers to the rear surface 1d of the secondary battery 1.

Hereinafter, referring to fig. 18A to 18L, a manufacturing process of the secondary battery 1 will be described. First, as shown in fig. 18A, the battery cell 3 and the substrate 35 are set in a jig, details of which are omitted. In some cases, at this time, the battery unit 3 is cut along the stacking width 28 of the battery assembly 27, and the stacking width 28 is folded along the side face of the battery unit 3 into a shape substantially trapezoidal with respect to the cross section thereof, thereby facilitating the processing; as described later, the folded stack width 28 functions as a buffer member when it is disposed between the side of the battery case 2 and the battery cell 3 during accommodation in the battery case 2. Further, on the substrate 35, a predetermined circuit pattern, and a positive electrode terminal portion 37 and a negative electrode terminal portion 38 are formed, and the positive electrode terminal plate 33 and the negative electrode terminal plate 34 are reflow-welded.

Incidentally, regarding the formation of the battery cells 3, in addition to forming the battery assembly 27 and cutting along the stacking width 28, a sealing sheet may be connected to a housing sheet in which the battery element 20 corresponding to each individual battery cell is housed.

The battery unit 3 is arranged in the following manner: the joint surface between the housing piece 24 and the sealing piece 26, from which the positive electrode terminal portion 21 and the negative electrode terminal portion 22 are drawn out, faces upward, and the bottom of the housing recess 25 faces downward. That is, the battery cells 3 for which the cross section is substantially trapezoidal form are arranged in the following manner: the short side faces downward, and the long side faces from which the positive electrode terminal portion 21 and the negative electrode terminal portion 22 are drawn upward. Also, the battery unit 3 is provided in the following manner: the lead surfaces 3a of the lead positive electrode terminal portion 21 and the negative electrode terminal portion 22 face the substrate 35 side. The substrate 35 is provided in the following manner: the mounting face on which the positive electrode terminal plate 33 and the negative electrode terminal plate 34 are mounted faces upward, while the short side face of the substantially trapezoidal shape faces the side face of the lead-out face 3a of the battery unit 3.

Then, as shown in fig. 18B, in the holder 30, the positive electrode sheet 31 and the negative electrode sheet 32 are inserted and held through the insertion holes 41, 42. Further, at this time, the ground wire 43 is also mounted on the holder 30. Then, as shown in fig. 18C, by mounting this holder 30 in a jig, the holder 30 is disposed between the battery cell 3 and the substrate 35. On the holder 30, the short side of the substantially trapezoidal shape in which the positive electrode sheet 31 and the negative electrode sheet 32 are held faces downward, and is positioned with respect to the short side of the substrate 35. Further, on the holder 30, one end 31a of the positive electrode tab 31 is placed above the positive electrode terminal 21 of the battery cell 3, and one end 32a of the negative electrode tab 32 is placed above the negative electrode terminal 22. Further, the other end 31b of the positive electrode tab 31 is placed on the positive electrode terminal plate 33 of the substrate 35, and the other end 32b of the negative electrode tab 32 is placed on the negative electrode terminal plate 34. In this way, the positive electrode terminal 21 and the negative electrode terminal 22 of the battery unit 3, the positive electrode tab 31 and the negative electrode tab 32 of the holder 30, and the positive electrode terminal plate 33 and the negative electrode terminal plate 34 of the base plate 35 are all located on substantially the same plane (see fig. 19).

Then, four positions of one end 31a and the other end 31b of the positive electrode tab 31 and one end 32a and the other end 32b of the negative electrode tab 32 are welded from the upper side, respectively, to connect the positive electrode terminal 21 of the battery unit 3 to one end 31a of the positive electrode tab 31, the negative electrode terminal 22 to one end 32a of the negative electrode tab 32, the positive electrode terminal plate 33 of the substrate 35 to the other end 31b of the positive electrode tab 31, and the negative electrode terminal plate 34 to the other end 32b of the negative electrode tab 32, respectively. At this time, although aluminum (Al) is used as the positive electrode terminal 21, since the positive electrode terminal 21 is welded from the upper side of the positive electrode tab 31 made of nickel, the mutual bonding of the two components can be secured without heat fusion.

Then, as shown in fig. 18D, the base plate 35 is erected, thereby placing the holder 30 thereon. At this time, on the respective other ends 31b, 32b of the positive and negative electrode sheets 31, 32 held by the holder 30, the base end portions protruding from the insertion holes 41, 42 on the side of the base plate 35 are folded in the standing direction of the base plate 35.

Then, as shown in fig. 18E, an insulating paper 51 is pasted so that the joint portions 50 between the positive electrode terminal portion 21 and the one end 31a of the positive electrode sheet 31 and between the negative electrode terminal portion 22 and the one end 32a of the negative electrode sheet 32 can be covered. The insulating paper 51 can not only strengthen the joint 50 between the positive and negative electrode terminals 21, 22 and the positive and negative electrode tabs 31, 32, but also prevent the occurrence of short circuits due to contact between the metal battery case 2 and the joint 50 and between the positive and negative electrodes due to deformation of the positive and negative electrode tabs 31, 32. On the insulating paper 51, an adhesive layer is formed on one surface side, and by folding the insulating paper 51 while sandwiching the joint portion 50, as shown in fig. 18F, the adhesive layers are stuck to each other, thereby completing the sticking work.

Then, as shown in fig. 18G, the holder 30 is connected to the top cover 36, thereby forming the battery cover 4. Thereafter, as shown in fig. 18H and fig. 13A, 13B, the joint portions 50 between the positive electrode terminal portion 21 and the one end 31a of the positive electrode tab 31 and between the negative electrode terminal portion 22 and the one end 32a of the negative electrode tab 32 are folded into a substantially S-shape so that the lead-out face 3A of the battery cell 3 and the battery lid 4 face each other. In this way, by accommodating the joint 50 in a bent state in the battery case 2, even when an impact acts between the battery unit 3 and the battery cover 4 due to dropping, shock, or the like, the impact load is absorbed by the joint 50 accommodated and folded into a substantially S-shape, so that separation or breakage between the positive electrode terminal 21 and the positive electrode sheet 31 and between the negative electrode terminal 22 and the negative electrode sheet 32 can be prevented (see fig. 13A and 13B).

Then, as shown in fig. 18I, in the battery cell 3, an elastic member 55 having a minute thickness and formed with adhesive layers on both sides thereof is stuck on the insertion end face 3b inserted into the battery case 2. This elastic member 55 not only allows the battery cell 3 to be fixed inside the battery case 2, thereby avoiding instability, but also absorbs the impact applied to the battery cell 3. Examples of the elastic member 55 include a pressure sensitive adhesive double coated tape (pressure sensitive adhesive coated tape) using a urethane foam as a base material. The insertion end face 3b of the battery unit 3 is not formed in a planar shape, but an end face whose shape is easily dispersed. However, such dispersion may be absorbed by the elastic member 55, so that it may be ensured that the battery cell 3 adheres to the inside of the battery case 2. Further, the elastic member 55 may absorb an impact acting on the battery cell 3 due to dropping, shock, or the like, or may reduce a load on the engaging portion 50 due to thermal expansion of the battery cell 3. Therefore, the elastic member 55 together with the above-described insulating paper 51 can prevent the occurrence of separation between the positive electrode terminal 21 and the positive electrode sheet 31 and between the negative electrode terminal 22 and the negative electrode sheet 32.

When the elastic member 55 is formed in a substantially rectangular shape and disposed at both ends in the longitudinal direction along the side surfaces of the battery cell 3 according to the shape of the insertion end surface 3b of the battery cell 3, an insulating film 56 for insulating the stacking width 28 of the battery cell 3 from the battery case 2 is pasted. That is, the housing sheet 24 and the sealing sheet 26 constituting the package 23 of the battery cell 3 are each a sheet shape in which a polypropylene (PP) layer 52, an aluminum (Al) layer 53, and a nylon layer 54 are pasted in the order from the inside described above. When the cutting is performed along the stacking width 28, the corresponding layer configured in a sheet shape on the cut surface is exposed to the outside. In the middle, when the aluminum layer 53 is directly in contact with the metal battery case 2, the aluminum layer 53 becomes a negative electrode if the battery case 2 is charged. When the polypropylene layer 52 has also pores for some reason, the aluminum layer 53 also has pores by electrolytic etching. Also, it is possible that the battery cell 3 may swell when moisture intrudes from the hole of the package member 23. Then, by providing the insulating film 56 along the cut surface of the battery cell 3, it is possible to design to achieve insulation between the battery case 2 and the cut surface of the package member 23, thereby preventing the battery cell 3 from swelling due to moisture absorption by the battery element 20.

The insulating film 56 is a longitudinal film formed according to the side surfaces of the battery cell 3, and one end thereof is adhered to each end of the elastic member 55. As shown in fig. 20, when the battery cell 3 is inserted into the battery case 2 from the insertion end face 3b, the insulating film 56 is folded along the side face of the battery cell 3 by the side edge portion of the opening 5 of the battery case 2 and is disposed between the cut face of the folded stacking width 28 on the side face of the battery cell 3 and the side face of the battery case 2. In this way, contact between the aluminum layer 53 exposed on the cut surface of the stacking width 28 and the battery case 2 can be prevented.

Then, as shown in fig. 18J, the battery unit 3 is inserted into the battery case 2, and the opening 5 of the battery case 2 is closed by the battery cover 4. At this time, the battery unit 3 is inserted as follows: so that the short-side faces and the long-side faces, which are substantially trapezoidal in cross section, are adapted to the short-side faces and the long-side faces of the battery case 2, which is similarly formed substantially trapezoidal in cross section. In this way, the internal space of the battery case 2 can be sufficiently utilized so that a predetermined gap is provided between the battery case 2 and the battery cell 3. As shown in fig. 21A to 21C, when the battery cell 3 expands due to heat or the like, the gap becomes an edge, so that it is possible to avoid overloading of the joint portion 50 or deformation of the battery case 2 due to expansion of the battery cell 3. Incidentally, fig. 21A shows the case where both main surfaces of the battery cell 3 swell by the same amount; fig. 21B and 21C each schematically show the case where the two main surfaces of the battery cell 3 expand by different amounts.

Further, when the directions of the battery cells 3 are reversed, since the edge of each of the long sides of the battery cells 3 interferes with the edge formed in the circular arc shape of each of the short sides of the battery case 2, the insertion can be prevented, and it is possible to prevent the occurrence of erroneous insertion.

As shown in fig. 20, when the battery cell 3 is inserted, an insulating film 56 is provided along the side face of the battery cell 3 through the side of the opening 5 of the battery case 2. The battery unit 3 is attached to the bottom surface of the battery case 2 by an elastic member 55 attached to the insertion end surface 3 b. After the battery unit 3 is inserted, the engagement protrusion 47 protruding on the top cover 36 is pushed into the opening 5 while being bent, and then is engaged with the engagement hole 6. Thus, the battery cover 4 is fitted into the opening 5 of the battery case 2.

Further, when the battery cover 4 is assembled to the battery case 2, the joint portions 50 between the positive electrode terminal 21 and the positive electrode tab 31 and between the negative electrode terminal 22 and the negative electrode tab 32 are formed in a substantially S-shaped form between the battery unit 3 and the holder 30 in a bent state.

Then, as shown in fig. 18K, the external label 15 is stuck to the outer periphery of the battery case 2. The external label 15 is affixed such that the major face portion 16 curls the outer peripheral edge of the battery case 2; the first curled portion 17 curls the area other than the both end portions in the longitudinal direction along the bottom surface portion 7; and the second crimping portion 18 crimps the region other than the terminal hole 48 formed in the top cover 36 of the battery cover 4. Finally, as shown in fig. 18L, an information label 49 on which various information of the secondary battery 1 is described is attached to the main face portion of the long-side face of the battery case 2 to which the external label 15 has been attached, whereby the work related to the secondary battery 1 can be completed.

According to the secondary battery 1 having the above-described structure, assembly can be easily achieved by assembling the metal battery case 2 and the battery cover 4, which is formed by molding, to each other. Also, by forming the battery case 2 by drawing using a metal material, slimness and strength assurance can be achieved at the same time, so that a secondary battery capable of satisfying requirements such as miniaturization, slimness, and weight saving of electronic equipment can be provided. Further, by processing the metal battery case 2 or molding the battery cover 4 made of synthetic resin, it is possible to easily form the outer shape of the engaging hole 8 or the engaging portion 79, which engaging portion 79 becomes the mounting end in the process of mounting the secondary battery to the battery mounting portion of the electronic apparatus.

Moreover, in the secondary battery 1, when the battery case 2 and the battery cover 4 are formed into a substantially trapezoidal shape with respect to the cross section thereof in which the edge of each of the short sides is formed into a circular arc shape and the battery housing part 12 of the digital camera 10 side is formed into the same shape, if the insertion face is reversed front to back, the edge of the battery housing part 12 and the edge of the secondary battery 1 interfere with each other, thereby prohibiting the insertion. Thus, erroneous insertion can be surely avoided.

Further, in the battery can 2, a can bottom electrode 57 may be provided on the bottom face portion 7 of the non-stick external label 57 so as to utilize the electrode as a negative electrode or a ground electrode. Further, when both ends of the bottom face portion 7 of the external label 15 are not stuck as engaging portions to be engaged with the engaging piece 19 provided on the side of the electronic apparatus, even if repeated rubbing by the engaging piece 19 is received, it is possible to avoid occurrence of such a situation as breaking or separation of the external label 15. Moreover, by forming the pasting area of the external label 15 pasted on the bottom face portion 7 of the battery case 2 in the area corresponding to both the positive electrode terminal portion 37 and the negative electrode terminal portion 38 of the secondary battery 1, even when the secondary battery 1 is mounted in an erroneous direction of an electronic apparatus such as the digital camera 10 or the battery charger 80, which digital camera 10 or battery charger 80 is disposed corresponding to the position of each of the positive electrode terminal portion 37 and the negative electrode terminal portion 38, the occurrence of short circuit due to direct contact of the bottom face portion 7 can be avoided because the insulating external label pasted on the bottom face portion 7 of the secondary battery 1 is brought into contact with the digital camera 10 or the battery charger 80 side. Further, by crimping the external label 15 onto the region other than the region where each of the positive electrode terminal portion 37 and the negative electrode terminal portion 38 of the battery cover 4 is formed, the fitting strength between the battery case 2 and the battery cover 4 can be enhanced. Therefore, since it is not necessary to protrude the engaging projection 47 formed on the battery cover 4 engaged with the battery case 2 at the upper face side of the battery case 2 from the engaging hole 6, the assembling strength can be secured without affecting the flatness or appearance of the secondary battery 1.

Further, in the secondary battery 1, by making the positions of each of the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 formed on the battery lid 4 different depending on the function (such as the battery capacity), and making the battery case 2 and the battery lid 4 have the same shape, even when the type-incompatible secondary battery 1 is mounted on the incompatible digital camera 10, no electrical conduction occurs between the electrode terminals, thereby avoiding the occurrence of trouble.

Further, in the secondary battery 1, when the battery case 2 and the battery cell 3 are formed in substantially trapezoidal shapes with respect to the cross sections thereof, in which the edge line of each of the short sides is formed in a circular arc shape, it is possible to prevent the battery cell 3 from being erroneously inserted into the battery case 2, while the internal space of the battery case 2 can be effectively utilized. In this way, a gap can be provided, which can become an edge between the battery cell 3 and the inner wall of the battery case 2 when the battery cell 3 thermally expands. Therefore, even when the battery cell 3 thermally expands, the battery case 2 is not caused to deform, or an overload is not applied to the joint portions 50 between the positive electrode terminal 21 and the positive electrode tab 31 and between the negative electrode terminal 22 and the negative electrode tab 32.

Further, in the secondary battery 1, a battery cover 4 is provided having: a holder 30 designed to position and fix the positive electrode sheet 31 and the negative electrode sheet 32; a substrate 35 provided with a positive electrode terminal portion 37 and a negative electrode terminal portion 38; and a top cover 36 for sandwiching the substrate 35 together with the holder 30. In this way, in the holder 30, by designing to position and hold the positive electrode tab 31 and the negative electrode tab 32, welding with the positive electrode terminal 21 and the negative electrode terminal 22, or welding with the positive electrode terminal plate 33 and the negative electrode terminal plate 34 can be easily achieved. Moreover, even when an impact is applied due to dropping or vibration of the secondary battery 1, or the like, occurrence of a welded portion between the positive electrode sheet 31 and the negative electrode sheet 32 can be avoided.

Further, in the secondary battery 1, since the battery case 2 is mounted on the insertion end face 3b of the battery cell 3 via the elastic member 55, not only can the instability of the battery cell 3 inside the battery case 2 be avoided, but also the impact due to the dropping or the shock of the battery case 2 or the like can be absorbed, thereby avoiding the impact from acting on the engaging portion 50. Also, by folding the stack width 28 along the side and then inserting the battery cell 3 into the battery case 2, the folded stack width 28 can be made to function as a buffer member between the battery cell 3 and the battery case 2.

Further, in the secondary battery 1, by sticking the insulating film 56 to the elastic member 55, when the battery cell 3 is inserted into the battery case 2, the insulating film 56 is provided along the side face of the battery cell 3 while being guided onto the side face of the opening 5 of the battery case 2 to cover the aluminum layer 53 of the package member 23 exposed on the cut face of the stacking width 28, so that it can be designed to be insulated from the inner wall of the battery case 2. Therefore, even when the metal battery case 2 is charged, the following phenomenon can be prevented: the battery case 2 is in direct contact with the aluminum layer 53 of the package member 23 to become a negative electrode, and the polypropylene layer 52 has a hole for some reason, thereby causing electrolytic corrosion, the package member 23 has a hole, and moisture intrudes from the hole, thereby causing swelling of the battery cell 3.

Further, in the secondary battery 1, since the insulating paper 51 is stuck to the joint portions 50 between the positive electrode terminal 21 and the positive electrode tab 31 and between the negative electrode terminal 22 and the negative electrode tab 32, not only the joint portions 50 can be reinforced, but also the occurrence of contact with the metal battery case 2 to cause a circuit can be prevented. Moreover, by the joint portion 50 being accommodated in the battery case 2 while being bent into the substantially S-shape, even when an impact acts between the battery unit 3 and the battery cover 4 due to dropping or vibration of the secondary battery 1 or the like, the joint portion 50, which has been folded into the substantially S-shape and accommodated, is bent, so that the impact load is absorbed, thereby preventing the positive electrode terminal 21 and the positive electrode tab 31 and the negative electrode terminal 22 and the negative electrode tab 32 from being separated.

Incidentally, as described previously, in the secondary battery 1 to which the present invention is applied, the battery cell 3 is adhered inside the battery case 2 by the elastic member 55. However, as shown in fig. 22A to 22C, a structure may be employed in which, before inserting the battery cell 3, an adhesive 58 is applied to one main surface inside the battery case 2, the adhesive 58 being distributed on the one main surface inside the battery case 2 by inserting the battery cell 3 into the battery case 2, thereby adhering the battery cell 3 to the battery case 2. By adopting such a structure, the battery unit 3 can be fixed in the battery case 2, so that it is possible to avoid instability of the battery unit 3 inside the battery case 2 due to dropping or vibration of the secondary battery 1, or the like. Therefore, no overload acts on the joint portions 50 between the positive electrode terminal 21 and the positive electrode tab 31 and between the negative electrode terminal 22 and the negative electrode tab 32, so that the positive electrode terminal 21 and the positive electrode tab 31 and the negative electrode terminal 22 and the negative electrode tab 32 can be prevented from being separated.

Further, by fixing the battery cell 3 inside the battery case 2 using the adhesive 58, the internal space of the battery case 2 can be effectively utilized, and a predetermined gap can also be formed between the main surface of the battery cell 3 on the side opposite to the adhesion surface and the inner wall of the battery case 2 opposite to the above main surface. Therefore, as shown in fig. 23, even if the battery cell 3 thermally expands, since the gap can secure an edge that prevents the volume expansion of the battery cell 3, it is possible to prevent the battery case 2 from being deformed or an overload from being applied to the engaging portion 50.

Further, in the secondary battery to which the present invention is applied, not only a structure in which a single battery cell 3 is inserted into a battery case 2, but also a structure in which a battery stack body (stack)61 in which a plurality of battery cells 3 are stacked is formed and the battery stack body 61 is inserted into a single battery case 62 as shown in fig. 24 may be employed. The secondary battery 60 configured to accommodate the battery stack body 61 therein will be described below. Incidentally, the same reference numerals are given to the same elements as in the above-described secondary battery 1, while the details thereof will be omitted.

In the battery laminated body 61, a plurality of battery cells 3 are stacked together in such a manner that the lead-out faces 3a from which the positive electrode terminal 21 and the negative electrode terminal 22 are led out face in the same direction, and the respective battery cells 3 may be adhered to each other if desired. In the battery laminated body 61, the positive electrode terminal 21 and the negative electrode terminal 22 drawn from each battery cell 3 are welded to a positive electrode terminal plate 66 and a negative electrode terminal plate 67, respectively, on a substrate 65 constituting a battery cover 64.

On the battery laminate 61, the battery cells 3 are stacked together by folding the above-described battery assembly 27 along the stacking width 28. The battery cells 3 may be stacked in two layers as shown in fig. 24, or may be stacked in three layers as shown in fig. 25. When the battery cells 3 are stacked in three layers, as shown in fig. 26, the battery assembly 27 is formed such that the overlap width W between the respective battery cells 3 is set₁And W₂Different. In the secondary battery 60, the battery capacity and voltage can be arbitrarily set by the number of stacked battery cells 3 and the difference in wiring between the respective battery cells 3.

Incidentally, by cutting and stacking the battery cells 3 separately from the battery assembly 27, the battery laminate 61 can be formed so that the lead-out surfaces 3a face in the same direction.

On the substrate 65, there are formed a positive electrode terminal plate 66 and a negative electrode terminal plate 67, and a positive electrode terminal portion 71 and a negative electrode terminal portion 72 connected to the positive electrode terminal plate 66 and the negative electrode terminal plate 67 through circuit patterns, respectively, wherein the positive electrode terminal plate 66 and the negative electrode terminal plate 67 are welded to the positive electrode terminal 21 and the negative electrode terminal 22 drawn out from each battery cell 3, and the positive electrode terminal portion 71 and the negative electrode terminal portion 72 are directed to the outside through a terminal hole 70 formed on the top cover 69.

In the secondary battery 60, the stacked battery cells 3 may be arranged by the circuit pattern of the substrate 65 so that they may be connected in series or in parallel. Such a circuit pattern is formed by an etching process using a copper foil, a printing process using a conductive agent, or the like. Further, a positive electrode terminal plate 66 and a negative electrode terminal plate 67 are formed on the land by reflow soldering. The positive electrode terminal portion 71 and the negative electrode terminal portion 72 are formed on lands formed on predetermined positions by gold plating or the like. Incidentally, similarly to the above-described secondary battery 1, the positive electrode terminal portion 71 and the negative electrode terminal portion 72 may be disposed at different positions depending on the difference of each function, such as the battery capacity of the secondary battery 60. The base plate 65 is sandwiched by the holder 68 and the top cover 69, and constitutes the battery cover 64 together with the holder 68 and the top cover 69.

The holder 68 is connected to the top cover 69 via the base plate 65, thereby sandwiching the base plate 65 together with the top cover 69. In this way, the holder 68 receives the pressing forces acting on the positive electrode terminal portion 71 and the negative electrode terminal portion 72 together with the top cover 69, so that it is possible to avoid a situation where an overload acts on the positive electrode terminal portion 71 and the negative electrode terminal portion 72. The holder 68 is prepared by molding synthetic resin into substantially the same shape as the opening 63 of the battery case 62. Further, in the holder 68, a plurality of coupling projections 73 that engage with coupling holes 74 formed in the top cover 69 are intermittently formed on the upper face 68a and the lower face 68 b.

The top cover 69 holding the substrate 65 together with the holder 68 is a member prepared by: the synthetic resin is molded into substantially the same shape as the opening 63 of the battery case 62, and the top cover 69 can be tightly engaged with the opening 63. On the top cover 69, on the upper face 69a and the lower face 69b, a plurality of connection holes 74 corresponding to the connection projections 73 are intermittently formed, wherein the plurality of connection projections 73 projecting on the holder 68 are inserted and engaged in the plurality of connection holes 74. Further, on the top cover 69, on the upper and lower faces 69a and 69b, a plurality of engaging projections 77 are formed with which engaging holes 76 formed on the outer periphery of the opening 63 of the battery case 62 are engaged. Further, when the top cover 69 is inserted into the battery case 62 from the opening 63 while the upper and lower faces 69a and 69b are slightly bent, the engaging projections 77 are engaged with the engaging holes 76 and fitted to the battery case 62.

Further, on the top cover 69, a terminal hole 70 is projected from the front surface 69c so that a positive electrode terminal portion 71 and a negative electrode terminal portion 72 formed on the substrate 65 can be directed to the outside, and the positive electrode terminal portion 71 and the negative electrode terminal portion 72 are brought into contact with an electrode terminal on the side of an electronic apparatus such as the digital camera 10 or a battery charger 80 through the terminal hole 70.

After the positive electrode terminal 21 and the negative electrode terminal 22 of the battery unit 3 are connected to the positive electrode terminal plate 66 and the negative electrode terminal plate 67 of the base plate 65, respectively, on the top cover 69, the top cover 69 and the holder 68 are connected while sandwiching the base plate 65 by inserting the connecting projection 73 of the holder 68 into the connecting hole 74, thereby forming the battery cover 64. Thereafter, when the engaging projection 77 of the top cover 69 is engaged with the engaging hole 76 formed on the outer periphery of the opening 63 of the battery case 62, the battery cover 64 is fitted to the battery case 62, thereby forming the secondary battery 60.

The battery case 62 into which the battery layered body 61 is inserted is constituted by a metal case in which one face of a substantially flat cuboid is open, and the battery case 62 is formed into a substantially rectangular shape with respect to its cross section according to the shape of the battery layered body 61. In the battery case 62, an opening 63 for inserting the battery laminated body 61 is molded by drawing a metal material such as iron, formed only on one face. The battery case 62 may be formed in an elongated shape by adjusting the wall thickness to about 0.3mm, so that the thickness itself can be controlled to the maximum when the accommodation area of the battery cell 3 is not considered; meanwhile, by using a metal material, the battery case 62 may have mechanical strength against various impacts such as dropping and vibration. The opening 63 is an insertion end into which the battery stack 61 is inserted, and after the battery stack 61 is inserted, the opening 63 is closed by the battery cover 64. For this reason, a plurality of engaging holes 76 which engage with engaging projections 77 protruding from the battery cover 64 are perforated on the outer periphery of the opening 63. In the engaging hole 76, when the battery cover 64 is inserted into the opening 63, an engaging projection 77 protruding on the battery cover 64 is pushed into the opening 63 while being bent, and then is engaged with the engaging hole 76. Thus, the battery cover 64 is fitted to the battery case 62.

Incidentally, similarly to the above-described secondary battery 1, on the battery case 62, when it is externally connected to the battery mounting portion of the electronic apparatus on the bottom face portion opposite to the opening 63, or when it is mounted to the battery mounting portion of the battery charger 80, an engagement hole that engages with an engagement projection protruding on the battery mounting portion may be formed. Also, an engaging recess may be provided on the battery mounting portion, and an engaging protrusion may be formed on the bottom face portion of the battery case 62. Similarly, similarly to the above-described secondary battery 1, on the top cover 69, when it is externally connected to the battery mounting portion of the electronic apparatus at a predetermined position of the front surface 69c, or when it is mounted to the battery mounting portion of the battery charger 80, a concave engaging portion that engages with an engaging protrusion protruding on the battery mounting portion may be formed. Also, an engaging recess may be provided on the battery mounting portion, and a protruding engaging portion may be formed on the front surface 69c of the top cover 69.

Incidentally, on the battery case 62, similarly to the above-described secondary battery 1, after the battery case 62 is connected with the battery lid 64, the battery layered body 61 is inserted, and the opening 63 is closed with the battery lid 64, the insulating outer label 15 and the information label 49 on which various information of the secondary battery 60 is described are pasted. The structure and effect of the external label 15 are the same as those of the case of being stuck to the above-described secondary battery 1.

Also, in addition to the case where the battery case 62 is formed to be substantially rectangular in cross section, the battery case 62 may be formed to be substantially trapezoidal in cross section, in which an edge line in the short side direction is formed in a circular arc shape, as shown in fig. 27. By adopting such a shape, the secondary battery 60 can be prevented from being erroneously inserted into a battery mounting portion of an electronic apparatus such as the digital camera 10 or the battery charger 80.

The secondary battery 60 can be manufactured as follows. First, as shown in fig. 28, the battery assembly 27 is cut in such a manner that two or more battery cells 3 are successively cut in accordance with the number of stacked battery cells 3 and folded along the stacking width 28 so that the battery cells 3 are stacked together, thereby forming a battery layered body 61.

Then, as shown in fig. 29, the positive electrode terminal 21 and the negative electrode terminal 22 drawn out from each battery cell 3 of the battery laminate body 61 are welded together with the positive electrode terminal plate 66 and the negative electrode terminal plate 67 mounted on the substrate 65. Incidentally, on the substrate 65, a circuit pattern connecting the respective battery cells 3 in series or in parallel and the positive electrode terminal portion 71 and the negative electrode terminal portion 72 are formed in advance in a separate process, and the positive electrode terminal portion 71 and the negative electrode terminal portion 72 are mounted; and the substrate 65 is supported by the holder 68.

Then, the holder 68 and the top cover 69 are connected to each other to form a battery cover 64, and the battery stack body 61 is then inserted into the opening 63 of the battery case 62. At this time, on the battery laminate 61, by sticking the elastic member 55 provided with the insulating film thereon to the insertion end face 3b of each battery cell 3, the insulation of the package member 23 from the inner wall of the battery case 62 can be achieved by the insulating film 56 while inserting the battery case 62, or the package member 23 can be fixed to the battery case 62 by the elastic member 55.

After the battery stack 61 is inserted, the battery cover 64 is fitted into the opening 63 of the battery case 62. Thereafter, the external label 15 is affixed to the battery case 62. As described above, the external label 15 becomes a decorative label of the secondary battery 60, and may be designed to realize insulation of the metal battery case 62. Further, the external label 15 is provided with: a main surface portion 16 for curling an outer periphery of the battery case 62; a first crimping portion 17 for crimping regions other than both end portions in the longitudinal direction of the bottom surface portion of the battery case 62; and a second crimping portion 18 for crimping an area other than the terminal hole 70 formed on the top cover 69 of the battery cover 64.

In this way, in the secondary battery 60, both ends of the bottom surface portion of the battery case 62 become engagement portions that engage with the engagement pieces provided in the battery housing portion of the electronic apparatus. Also, when the external label 15 is pasted so as to smoothly curl the battery cover 64, the fitting strength between the battery cover 64 and the battery case 62 can be ensured without affecting the flatness and appearance.

According to the secondary battery 60 thus constructed, by using the battery laminate 61 in which the plurality of battery cells 3 are stacked as needed, a secondary battery having a high battery capacity or a long-life secondary battery can be easily obtained. Also, in the secondary battery 60, since the respective battery cells 3 can be connected in series or in parallel according to the circuit pattern formed on the substrate, high capacity or long service life can be obtained relatively easily.

Next, the battery charger 80 that charges the above-described secondary battery will be described. The battery charger 80 is used as a battery charger common to a plurality of kinds of secondary batteries 1, and these secondary batteries 1 are identical in external shape, but are different in that the positive electrode terminal portion 37 and the negative electrode terminal portion 38 facing the front face 1c are disposed at substantially point-symmetrical positions depending on the battery capacity or the compatible electronic device, whether or not there is a remaining battery life display function, and the type capable of achieving rapid discharge and the type incapable of achieving rapid discharge.

As shown in fig. 30, the battery charger 80 includes: a battery charging body 81; a battery housing portion 82 in which the secondary battery 1 is housed; an electrode terminal 83 provided in the battery housing portion 82 and contacting the positive electrode terminal portion 37 and the negative electrode terminal portion 38 of the secondary battery 1; and a transparent portion 84 through which the electrode terminal 83 can be viewed from the outside of the battery charger main body 81 through the transparent portion 84.

As shown in fig. 30, the battery charger main body 81 is formed of, for example, a cube larger than the secondary battery 1, and the battery housing portion 82 is formed on the main surface portion 81 a. The battery housing part 82 is a recess having substantially the same size as the secondary battery 1; and the electrode terminal 83 is formed on one side wall portion 82a corresponding to the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38, wherein the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are directed outward from the terminal hole 48 provided on the front surface 1c of the secondary battery 1. Further, in the battery charger main body 81, a transparent portion 84 capable of enhancing visibility of the electrode terminals 83 is formed from the side wall portion 82a where the electrode terminals 83 are formed to the main surface portion 81 a. By providing the transparent portion 84, the user of the battery charger 80 can easily observe the position of the electrode terminal 83 from the upper side. Moreover, in the process of mounting the secondary battery 1 to the battery housing part 82, it can be easily confirmed that the positive electrode terminal part 37 and the negative electrode terminal part 38 on the secondary battery 1 side are connected to the electrode terminal 83 on the battery charger main body 81 side without making the insertion direction wrong. Further, the battery charger main body 81 is provided with a cord for receiving an external power supply, a display portion for displaying a charging state by an LED element or a liquid crystal, and other parts, but details of these parts are omitted here.

Here, as described previously, the secondary battery 1 mounted in the battery charger 80 is formed in the following manner: the arrangement of the positive electrode terminal portion 37 and the negative electrode terminal portion 38 differs depending on functions such as whether it is a high battery capacity type, whether it has a function of displaying the remaining battery life by an LED, a liquid crystal, or a provided type member, a difference in compatible electronic devices, or whether it can be quickly discharged. That is, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 formed on the substrate 35 constituting the battery cover 4 are disposed at substantially point-symmetrical positions in accordance with each of the above functions, although the functions are different, while the outer shapes of the battery case 2 and the battery cover 4 constituting the secondary battery 1 are the same. Similarly, the electrode terminals provided on the side of the electronic device are arranged in an arrangement corresponding to the positive electrode terminal portion 37 and the negative electrode terminal portion 38 of the respective secondary batteries. In this way, even if the secondary battery 1 is mounted on an incompatible electronic apparatus, since the positive electrode terminal portion 37 and the negative electrode terminal portion 38 on the secondary battery 1 side do not come into contact with the electrode terminals provided on the electronic apparatus side, it is possible to prevent trouble caused by erroneous mounting. Incidentally, at this time, since the electrode terminals on the side of the electronic device are in contact with the front face 36c of the top cover 36 made of synthetic resin, direct contact with the metal battery case 2 can be prevented from occurring.

On the other hand, in charging the secondary battery 1, if a plurality of battery chargers are prepared corresponding to each function, this requires the user to use one type of charger for each purpose, and it is too complicated. In addition, the product supplier is also required to produce and operate multiple types of battery chargers, which is also too complicated.

Then, in the present battery charger 80, the mounting direction can be changed to be common to a plurality of secondary batteries 1 having the positive electrode terminal portion 37 and the negative electrode terminal portion 38 whose positions are different for each function. Specifically, in the secondary battery 1, since the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are provided at substantially point-symmetrical positions corresponding to each function, as shown in fig. 31, when the secondary battery 1B in which the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are provided at substantially point-symmetrical positions is rotated by 180 degrees, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 of the two secondary batteries 1A, 1B become at the same position as compared with the secondary battery 1A. Therefore, when the secondary battery 1A is mounted in the battery charger 80, the upper face 1A of the short-side face is positioned upward; and when the secondary battery 1B is mounted in the battery charger 80, the secondary battery 1B is rotated by 180 degrees so that the lower face 1B is positioned downward. In this way, in all the secondary batteries 1A, 1B, charging can be achieved by bringing the positive electrode terminal portion 37 and the negative electrode terminal portion 38 into contact with the electrode terminal 83 formed on the battery charger 80 side.

Incidentally, regardless of the mounting direction of the secondary batteries 1A, 1B, it can be easily confirmed by the transparent portion 84 whether or not each of the positive electrode terminal portion 37 and the negative electrode terminal portion 38 is in contact with the electrode terminal 83 of the battery charger main body 81. Further, it is possible to confirm whether the mounting direction of the secondary batteries 1A, 1B is correct or not by the display section for displaying the state of charge or the like.

Here, when the secondary battery 1A is mounted with the lower face 1B directed upward and the secondary battery 1B is mounted with the upper face 1A directed upward, since each of the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 is not in contact with the electrode terminal 83, charging is not achieved. At this time, since the electrode terminals 83 are in contact with the front surface 36c of the top cover 36 made of synthetic resin, direct contact with the metal battery case 2 can be prevented from occurring. Further, even if the secondary batteries 1A, 1B are mounted with the front face 1A and the rear face 1d reversed, since the electrode terminals 83 are in contact with the rear face 1d of the secondary battery 1, charging is not effected. At this time, since the electrode terminal 83 is in contact with the first curl portion 17 of the external label 15 stuck on the bottom surface of the battery case 2, it is possible to prevent the occurrence of direct contact with the metal battery case 2.

Further, such a compatible battery charger may be constructed as follows. As shown in fig. 32, the battery charger 90 is provided with: a battery charger main body 91 having a substantially rectangular shape; a holding arm 92 slidably supported by the mutually opposing side faces 91a, 91b of the battery charger main body 91 and supporting the secondary battery 1; and an electrode terminal 93 provided on the front face 91c of the battery charger main body 91. On this battery charger 90, the secondary battery 1A or 1B in which the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are disposed at substantially point-symmetrical positions may be mounted from one direction or the other of the holding arms 92 that hold the secondary battery 1.

The holding arm 92 is provided with: a pair of arm portions 95, 95 slidably supported by both side surfaces 91a, 91b of the battery charger king body 91; and a holding portion 96 that is provided at the tip end portions of the arm portions 95, 95 across the pair of arm portions 95, and holds the secondary battery 1A or 1B.

The arm portions 95, 95 are longitudinal members that, when slidably supported by both side surfaces 91a, 91b of the battery charger main body 91 at intervals substantially equal to the width of the secondary battery 1, can pull the arm portions 95, 95 outward to the front surface 91c side of the battery charger main body 91. The holding portion 96 formed on the tip end portions of the arm portions 95, 95 is a substantially T-shaped member which supports the battery case 2 of the secondary battery 1, and has a support wall 97, the support wall 97 constituting the front face of the battery charger main body 91 and supporting the bottom face portion of the battery case 2, and a placement face portion 98 which projects from a substantially central position in the height direction of the support wall 97, across the arm portions 95, toward the front face 91c side of the battery charger main body 91, wherein both faces thereof are placement faces 98a, 98b on which the rear end portion of the battery case 2 is placed.

When the arm portions 95, 95 slide toward the rear surface 91d of the battery charger main body 91, the support wall 97 becomes the front surface of the battery charger main body 91. When the arms 95, 95 slide toward the front surface 91c of the battery charger main body 91 and the secondary battery 1 is mounted on the support arm 92, the support wall 97 supports the bottom surface 7 of the battery case 2.

On the placement surface portion 98, both placement surfaces 98a, 98b are inclined surfaces inclined toward the center in the thickness direction of the front surface 91c in the direction from the support wall 97 to the front surface 91c side of the battery charger main body 91. Further, in the process of mounting the secondary battery 1 to the holding arm 92, the rear end portion of the battery case 2 is placed, and the placement face portion 98 is inclined in such a manner that the front face 36c of the top cover 36, which is faced by the positive electrode terminal portion 37 and the negative electrode terminal portion 38, is brought into contact with the electrode terminal 93 formed on the front face 91c of the battery charger main body 91. That is, when the rear end portion of the battery case 2 is placed on the two placement faces 98a, 98b of the placement face portion 98, the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are brought into contact with the electrode terminal 98 of the battery charger main body 91.

The holding arm 92 holds the secondary battery 1 by the pair of arm portions 95, the placement surface 98a or 98b, and the support wall 97. At this time, as shown in fig. 33A and 33B, the holding arms 92 hold the secondary battery 1A on the placing face 98a and the secondary battery 1B on the placing face 98B, respectively, according to the functions, in which the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are disposed at substantially point-symmetrical positions. At this time, the secondary batteries 1A, 1B are each mounted on the holding arm 92 with the lower surface thereof being an insertion surface. Further, the secondary battery 1A held on the mounting surface 98a and the secondary battery 1B held on the mounting surface 98B are mounted while being rotated 180 degrees from each other. In this way, in all the secondary batteries 1A, 1B, since the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are rotated to the same position, they can be brought into contact with the electrode terminal 93 formed on the front face 91c side of the battery charger main body 91, so that charging can be completed.

Incidentally, when the secondary batteries 1A, 1B are mounted from the upper face 1A side while inverting the insertion faces, if the secondary battery 1A is mounted on the mounting face 98B side or if the secondary battery 1B is mounted on the mounting face 98a side, since the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are not in contact with the electrode terminal 93 formed on the front face 91c of the battery charger main body 91, charging is not performed. At this time, since the electrode terminals 93 are in contact with the front surface 36c of the top cover 36 made of synthetic resin, direct contact with the metal battery case 2 can be prevented from occurring. Also, when the secondary batteries 1A, 1B are mounted while the upper face 1A and the rear face 1d are reversed, since the electrode terminals 93 are in contact with the rear face 1d of the secondary batteries 1A and 1B, charging is not performed. At this time, since the electrode terminal 93 is in contact with the first curl portion 17 of the external label 15 adhered on the bottom surface of the battery case 2, the electrode terminal 93 can be prevented from being in direct contact with the battery case 2 made of metal.

Further, as shown in fig. 34, since the arm portions 95, 95 can slide toward the rear face 91d side of the battery charger main body 91 when not in use, the battery charger 90 has excellent portability, and the arm portions 95, 95 and the like can be prevented from being broken.

Further, such a compatible battery charger may be constructed as follows. As shown in fig. 35, the battery charger 100 is provided with: a battery charger main body 101 which is substantially rectangular; a battery mounting portion 102 provided on an upper surface 101a of the battery charger main body 101; an electrode terminal 103 that is formed inside the battery mounting portion 102 and that is in contact with the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38; and a pair of battery holders 104A, 104B rotatably provided on the upper surface 101A of the battery charger main body 101 and holding the secondary batteries 1A, 1B. On this battery charger 100, the secondary battery 1 is mounted on the battery holder 104A or 104B by changing its orientation in accordance with the arrangement of the positive electrode terminal portion 37 and the negative electrode terminal portion 38, whereby the electrode terminal 103 of the battery mounting portion 102 can be brought into contact with the positive electrode terminal portion 37 and the negative electrode terminal portion 38, and not only can compatibility of various types of secondary batteries 1A, 1B be ensured, but also insertion into the battery holder 104A or 104B can be inhibited when the orientation is inappropriate. Therefore, erroneous mounting of the secondary batteries 1A, 1B can be avoided.

The battery charger main body 101 is formed in a substantially rectangular box-like shape, and a battery mounting portion 102, to which the secondary battery 1 is mounted from the front face 1c side, is formed at a substantially central position of the upper face 101 a. The battery charger main body 101 is provided with a pair of battery holders 104A and 104B on the upper surface 101a so as to rotate upward.

The battery mount section 102 is a recess in which the secondary battery 1 is mounted from the front side, and the battery mount section 102 is opened in a substantially rectangular shape in accordance with the shape of the secondary battery 1. On the bottom surface portion of the battery mounting portion 102, there are formed electrode terminals 103 that are in contact with the positive electrode terminal portion 37 and the negative electrode terminal portion 38, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 facing the front surface 1c of the secondary battery 1.

Battery holders 104A, 104B hold the secondary batteries 1A, 1B mounted in the battery mounting portion 102, respectively, wherein the battery holder 104A holds the secondary battery 1A as shown in fig. 36A; as shown in fig. 36B, the battery holder 104B holds the secondary battery 1B. The battery holders 104A, 104B have: battery housing parts 105A, 105B for housing the secondary battery 1 therein; and a pair of arm portions 106A, 106B that continuously protrude and are formed respectively from a pair of side face portions in each of the battery housing portions 105A, 105B, and are rotatably supported by the battery charger main body 101. Further, the battery holder 104 is formed such that the battery housing portion 105A is rotatable toward the upper side from the front side of the upper face 101a of the battery charger main body 101 while using the bottom end portions of the pair of arm portions 106A as rotation fulcrums; and the battery holder 104B is formed such that the battery housing portion 105A is rotatable toward the upper side from the rear side of the upper face 101a of the battery charger main body 101 while using the bottom end portions of the pair of arm portions 106B as the rotation fulcrums.

The battery housing parts 105A, 105B are formed in a substantially rectangular box-like shape in accordance with the shape of the secondary battery 1, wherein one main surface into and from which the secondary battery 1 is inserted and removed and the lower surface on the battery mounting part 102 side are opened. Further, the battery housing portions 105A, 105B may be mounted by inserting the secondary battery 1 from the lower face 1B side.

The battery holders 104A, 104B are mounted in such a manner that the opening sides of the respective main faces oppose each other when the battery housing portion 105A and the battery housing portion 105B are rotated upward toward the battery charger main body 101. That is, in the battery housing parts 105A, 105B, each rear wall thereof is directed upward when mounted on the upper face 101a of the battery charger main body 101, as shown in fig. 35; when the battery housing portion 105A is rotated upward, in the battery holder 104A, the rear wall of the battery housing portion 105A faces the rear side of the battery charger main body 101 as shown in fig. 36A, while in the battery holder 104B, the rear wall of the battery housing portion 105B faces the front side of the battery charger main body 101 as shown in fig. 36B. In this way, the secondary battery 1A mounted in the battery holder 104A and the secondary battery 1B mounted in the battery holder 104B are mounted opposite to each other with respect to the battery mounting portion 102 provided on the upper face 101A of the battery charger main body 101.

A pair of arm portions 106A, 106B rotatably supported while sandwiching the battery mounting portion 102 of the battery charger main body 101 therebetween; when rotated along the front face side or the rear face side of the battery charger main body 101, they can hold the battery holders 104A, 104B substantially flush with the upper face 101a, whereas when the battery charger main body 101 is rotated upward, they lift the battery holders 104A, 104B so that the secondary battery 1 is mounted therein.

In the pair of arm portions 106A, 106B, the respective bottom end portions are supported while sandwiching both end portions in the longitudinal direction of the battery mounting portion 102 provided on the upper face 101a of the battery charger main body 101. Further, since the battery holder 104A is formed to have a narrower width than the battery holder 104B, the base end portions of the arm portions 106A are supported in the battery charger main body 101 at positions further inward than the base end portions of the arm portions 106B. Thus, in the battery holder 104A and the battery holder 104B, when either one is rotated upward, the rotation of the other is prohibited. Therefore, only one of the secondary battery 1A and the secondary battery 1B can always be in contact with the electrode terminal 103.

In charging the secondary batteries 1A, 1B with the charger 100 described above, in which the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are provided at substantially point-symmetrical positions corresponding to each function, either one of the battery holders 104A or 104B is rotated upward in accordance with the position of the secondary battery 1 terminal. When the battery holder 104A is rotated upward (see fig. 36A), the secondary battery 1A is inserted into the battery housing portion 105A in such a manner that the lower face 1b is an insertion end face. In this way, in the secondary battery 1A, the front surface 1c side is mounted into the battery mounting portion 102, and the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are brought into contact with the electrode terminal 103, whereby charging is effected.

Incidentally, when the secondary battery 1A is intentionally inserted from the upper face 1A side, the insertion into the battery housing portion 105A is prohibited. Also, when the secondary battery 1B is inserted into the battery holder 104A, since the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are formed oppositely so as to need to be rotated by 180 degrees, the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are not brought into contact with the electrode terminal 103 of the battery mounting portion 102, and thus are not charged. At this time, since the electrode terminals 103 are in contact with the front surface 36c of the top cover 36 made of synthetic resin, direct contact with the metal battery case 2 can be prevented from occurring. Further, when the secondary battery 1A is inserted reversely, since the electrode terminals 103 are in contact with the rear side 1d of the secondary battery 1, charging is made impossible. At this time, since the electrode terminal 103 is in contact with the first curl portion 17 of the external label 15 attached to the bottom surface portion 7 of the battery case 2, it is possible to prevent direct contact with the metal battery case 2 from occurring.

Further, when the battery holder 104B is rotated upward (see fig. 36B), the secondary battery 1B is inserted into the battery housing portion 105B in such a manner that the lower face 1B is an insertion end face. In this way, in the secondary battery 1B, the front face 1c side is fitted into the battery mounting portion 102, here, since the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are formed at substantially point-symmetrical positions in contrast to the secondary battery 1A, when the secondary battery 1B is inserted into the battery housing portion 105B in the opposite direction to the secondary battery 1A inserted into the battery housing portion 105A, the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are rotated to the same position as the secondary battery 1A with respect to the electrode terminal 103 of the battery mounting portion 102. Therefore, in the secondary battery 1B, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are in contact with the electrode terminal 103, thereby performing charging.

Incidentally, when the secondary battery 1B is intentionally inserted from the upper face 1a side, the insertion into the battery housing portion 105B is prohibited. Moreover, when the secondary battery 1A is inserted into the battery holder 104B, since the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are formed to be opposed in position so as to need to be rotated by 180 degrees, the positive-electrode terminal portion 37 and the negative-electrode terminal portion 38 are not brought into contact with the electrode terminal 103 of the battery mounting portion 102, and therefore, are not charged. At this time, since the electrode terminals 103 are in contact with the front surface 36c of the top cover 36 made of synthetic resin, direct contact with the metal battery case 2 can be prevented from occurring. Further, when the secondary battery 1B is inserted reversely, since the electrode terminals 103 are in contact with the rear side 1d of the secondary battery 1, charging is made impossible. At this time, since the electrode terminal 103 is in contact with the first curl portion 17 of the external label 15 attached to the bottom surface portion 7 of the battery case 2, direct contact with the metal battery case 2 can be prevented.

In view of the above, in all the secondary batteries 1A, 1B, since the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are rotated to the same position, the positive electrode terminal portion 37 and the negative electrode terminal portion 38 are brought into contact with the electrode terminal 103 formed on the battery mounting portion 102, and therefore, charging can be achieved. Thus, the battery charger 100 can be shared.

Moreover, in the battery charger 90, since the battery holder 104 can be rotated to the upper side 101a side of the battery charger main body 101 when not in use, the battery charger 90 has excellent portability characteristics and the breakage of the battery holder 104 can be avoided.

It should be understood by those skilled in the art that various changes, combinations, substitutions and alterations can be made herein without departing from the scope of the invention as set forth in the appended claims and equivalents thereof, depending upon design requirements and other factors.

Claims (8)

1. A secondary battery for an electronic device, which is housed in the electronic device so as to supply electric power to the electronic device, comprising:

a battery cell in which a positive electrode, a negative electrode, and an electrolyte are contained in a package, and a positive electrode terminal and a negative electrode terminal from the positive electrode and the negative electrode are respectively led out from the same side of the package;

a metal battery case in which one opening into which the battery cell is inserted is formed, and the battery cell is housed in the metal battery case such that a side from which the positive electrode terminal and the negative electrode terminal are drawn faces the opening; and

a cover made of synthetic resin, wherein a positive electrode terminal portion and a negative electrode terminal portion to be connected to electrodes of an electronic device are disposed once the positive electrode terminal portion and the negative electrode terminal portion are connected to the positive electrode terminal and the negative electrode terminal and are directed outward, and the opening of the battery case is plugged with the cover,

the positive electrode terminal and the negative electrode terminal are each bent in an S-shape with respect to a respective cross section, the battery cell is housed in the battery case while the positive electrode terminal and the negative electrode terminal are bent between the positive electrode terminal and the negative electrode terminal and the lid,

the cover includes; a holder for inserting and holding the positive electrode sheet and the negative electrode sheet; a substrate having a positive electrode terminal plate and a negative electrode terminal plate formed on one surface thereof, and having a positive electrode terminal portion connected to the positive electrode terminal plate and a negative electrode terminal portion connected to the negative electrode terminal plate formed on the other surface thereof; and a top cover provided with a terminal hole from which the positive electrode terminal portion and the negative electrode terminal portion face outward, the holder and the top cover being integrally connected to each other so as to sandwich the substrate therebetween; and is

The positive electrode tab is welded at one end thereof to the positive electrode terminal and at the other end thereof to the positive electrode terminal plate, and the negative electrode tab is welded at one end thereof to the negative electrode terminal and at the other end thereof to the negative electrode terminal plate.

2. The secondary battery according to claim 1, wherein the battery cell is adhered to an inner wall of the battery case.

3. The secondary battery according to claim 1, wherein:

the positive electrode terminal and the negative electrode terminal are drawn out from an upper portion of a drawing-out face of the battery cell, while the positive electrode sheet and the negative electrode sheet are inserted and held in the vicinity of a lower side edge of the holder; and

after the positive and negative electrode terminals and the positive and negative electrode sheets are placed on substantially the same face and connected, the holder is made to oppose the lead-out face of the battery cell, thereby bending the joint portions between the positive electrode terminal and the positive electrode sheet and between the negative electrode terminal and the negative electrode sheet.

4. The secondary battery according to claim 1, wherein:

on the positive electrode sheet and the negative electrode sheet, connection end portions between the positive electrode sheet and the positive electrode terminal and between the negative electrode sheet and the negative electrode terminal are made to stand in a circular arc shape along curved surfaces of the positive electrode terminal and the negative electrode terminal, respectively.

5. The secondary battery according to claim 1, wherein insulating paper is pasted on the joint portions between the positive electrode terminal and the positive electrode sheet and between the negative electrode terminal and the negative electrode sheet.

6. The secondary battery according to claim 2, wherein a pressure-sensitive adhesive double-coated tape made of an elastic material is stuck to the insertion end surface of the battery case, and the battery cell is stuck to the bottom surface portion of the battery case by the pressure-sensitive adhesive double-coated tape.

7. The secondary battery according to claim 6, wherein:

in the battery cell, a cut surface of the package member is exposed on both side surfaces perpendicular to an insertion direction of the battery cell; and

the pressure-sensitive adhesive double coated tape is provided with an insulating film that is folded along a side surface of the battery case and covers the cut surface of the battery cell after the battery cell is inserted into the battery case.

8. The secondary battery according to claim 2, wherein the battery cell is adhered to an inner circumferential surface of the battery case by an adhesive supplied to the inner circumferential surface.