JP2005149783A - Secondary battery, assembled battery, composite assembled battery and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide secondary batteries which are arrayed with good precision when arranging them into a battery pack. <P>SOLUTION: The secondary battery comprises: laminated electrodes 101 composed of positive electrodes and negative electrodes laminated alternately through separators; electrode terminals 105, 106 connected to the laminated electrodes; and outer package members 107, 108 housing the laminated electrodes 101 and the electrode terminals in a space formed inside, of which an outer peripheral edge part is sealed, with a part of the electrode terminals led out from the outer peripheral edge thereof. The electrode terminal has first parts 105a, 106a having a width W practically the same as the width W<SB>1</SB>of the laminated electrode 10 and second parts 105b, 106b having a width narrower than that of the first parts. The first parts of the electrode terminal, to which the electrode terminal is connected, are located in a space formed inside the outer package member, and the second parts located at the outer periphery edge of the outer package member is thermally welded to the outer package member 1, and is led out from the outer periphery edge of the outer package member. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a secondary battery in which electrode plates are stacked via a separator, accommodated in an exterior member and sealed, and electrode terminals are led out from an outer peripheral edge of the exterior member.

  Conventionally, an electrode member having an electrode plate laminated via a separator is connected to an electrode terminal having a narrower width than the electrode laminate, and the electrode laminate and the electrode terminal are made of a synthetic resin material or the like. A secondary battery in which a part of an electrode terminal is led out from the outer peripheral edge of an exterior member is known (for example, see Patent Document 1).

  When an assembled battery is configured using such a secondary battery (made into an assembled battery), it is necessary to dispose the secondary battery while positioning with reference to any external part of the secondary battery.

  In this positioning, when the secondary battery exterior member is used as a reference, since the exterior member is made of a synthetic resin material and is flexible, the secondary battery can be accurately placed when forming an assembled battery. I can't.

On the other hand, it is conceivable to perform positioning based on the electrode terminal derived from the exterior member, but since the width of the electrode terminal is narrower than the width of the electrode laminate as described above, this electrode terminal is In some cases, the secondary battery cannot be arranged with high accuracy when the battery pack is assembled because the electrode stack is not accurately connected to the body and the relative positional relationship of the electrode laminate with respect to the electrode terminals varies.
JP 2003-187857 A

An object of this invention is to provide the secondary battery which can be arrange | positioned with sufficient precision at the time of battery assembly.
In order to achieve the above object, according to the present invention, an electrode laminate having positive and negative plates laminated alternately via separators, an electrode terminal connected to the electrode laminate, and an internal structure And a sealing means in which the electrode laminate and the electrode terminal are accommodated in the formed space and the outer peripheral edge is sealed, and a part of the electrode terminal is led out from the outer peripheral edge. The electrode terminal has a first portion having substantially the same width as the electrode stack, and a second portion having a width narrower than the first portion, and the electrode A first portion of the terminal is located in a space formed inside the sealing means, and the electrode stack is connected, and a second portion of the electrode terminal is on the outer periphery of the sealing means. Positioned and sealed by the sealing means, and further led out from the outer periphery of the sealing means Secondary battery is provided.

  In the present invention, the electrode terminal of the secondary battery is provided with a first portion having a width substantially the same as that of the electrode stack and a second portion having a width narrower than the first portion. Then, the first portion is positioned in the space formed inside the sealing means and connected to the electrode stack, and the second portion is positioned on the outer periphery of the sealing means and sealed by the sealing means. And the second part is led out from the outer peripheral edge of the sealing means.

  First, by making the width of the first portion of the electrode terminal substantially the same as the width of the electrode stack, and connecting the first portion to the electrode stack, the electrode terminal and the electrode stack are moved in the width direction. Since the positional relationship in the width direction between the electrode terminal and the electrode laminate is regulated simply by overlapping, it is possible to eliminate variations in the relative positional relationship of the electrode laminate with respect to the electrode terminal. The battery can be arranged with high accuracy.

  Also, simply widening the width of the electrode terminal suppresses heat generation during large current charging / discharging, etc., while increasing the sealing portion by the sealing means, reducing the sealing performance and insulation of the sealing means. There is a case. On the other hand, in the present invention, the wide first portion of the electrode terminal is positioned in the space formed inside the sealing means, and the electrode terminal is provided with the narrow second portion, 2 is positioned on the outer peripheral edge of the sealing means and sealed by the sealing means, and further, the second portion is led out from the outer peripheral edge of the sealing means, thereby sealing by the sealing means, It is possible to ensure the cross-sectional area of the electrode terminal necessary for maintaining insulation and suppressing heat generation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 is a plan view of an entire secondary battery according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, FIG. 3 is an enlarged cross-sectional view of section III of FIG. FIG. 2 is a plan view showing an example of an electrode terminal of the secondary battery shown in FIG. 1. 1 and 2 show one secondary battery (unit battery), and a plurality of secondary batteries 10 are stacked and connected to form an assembled battery having a desired voltage and capacity.

  First, a secondary battery 10 according to an embodiment of the present invention will be described. The secondary battery 10 is a lithium-based thin secondary battery, and includes three positive electrode plates as shown in FIGS. 1 and 2. 102, seven separators 103, an electrode laminate 101 having three negative plates 104, a positive electrode terminal 105 and a negative electrode terminal 106 respectively connected to the electrode laminate 101, and the electrode laminate 101 and the electrode terminal 105 , 106 are sealed and are composed of an upper exterior member 107 and a lower exterior member 108, and an electrolyte (not shown).

  As shown in FIG. 3, the three positive electrode plates 102 constituting the electrode laminate 101 include a positive electrode current collector 102a extending to the positive electrode terminal 105 and a part of both main electrodes of the positive electrode current collector 102a. And a positive electrode layer 102b formed on each surface. In addition, the positive electrode layer 102b of the positive electrode plate 102 is not formed over both main surfaces of the entire positive electrode side current collector 102a, but when the electrode laminate 101 is configured as shown in FIG. In the positive electrode plate 102, the separator 103 is formed only in a portion where it substantially overlaps.

  The positive electrode side current collector 102 a of the positive electrode plate 102 is an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil having a thickness of about 20 μm.

The positive electrode layer 102b of the positive electrode plate 102 is a mixture of a positive electrode active material such as a metal oxide, a conductive agent such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene. It is formed by applying to a part of the main surface of the positive electrode side current collector 102a, drying and rolling. Examples of the positive electrode active material include lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), and lithium cobaltate (LiCoO ₂ ), and chalcogen (S, Se, Te) compounds. Etc. can be mentioned. These materials are relatively easy to dissipate the heat generated in the secondary battery, and can suppress the stress accompanying expansion due to the heat generated in the secondary battery. It is particularly effective.

  The negative electrode plate 104 constituting the electrode laminate 101 includes a negative electrode side current collector 104a extending to the negative electrode terminal 106, and a negative electrode layer 104b formed on both main surfaces of a part of the negative electrode side current collector 104a, respectively. have. The negative electrode layer 104b of the negative electrode plate 104 is not formed over both main surfaces of the negative electrode side current collector 104a, but constitutes the electrode laminate 101 in the same manner as the positive electrode layer 102b described above. At this time, the separator 103 is formed only in the portion where the separator 103 substantially overlaps in the negative electrode plate 104.

  The negative electrode side current collector 104a of the negative electrode plate 104 is an electrochemically stable metal foil such as a nickel foil, a copper foil, a stainless steel foil, or an iron foil having a thickness of about 10 μm.

  The negative electrode layer 104b of the negative electrode plate 104 is a negative electrode that occludes and releases lithium ions of the positive electrode active material, such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. An active material is mixed with an aqueous dispersion of styrene butadiene rubber resin powder as a precursor material of an organic fired body, dried and then pulverized to carry carbonized styrene butadiene rubber on the carbon particle surface. The main material is formed by further mixing a binder such as an acrylic resin emulsion with this, applying this mixture to both main surfaces of a part of the negative electrode side current collector 104a, and drying and rolling.

  In particular, if amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, the flatness of the potential during charge / discharge is poor, and the output voltage decreases with the amount of discharge. Is not suitable, but it is advantageous when used as a power source for an electric vehicle because there is no sudden drop in output.

  The separator 103 of the electrode laminate 101 prevents the short-circuit between the positive electrode plate 102 and the negative electrode plate 104 described above, and may have a function of holding an electrolyte. The separator 103 is a microporous film made of, for example, a polyolefin such as polyethylene (PE) or polypropylene (PP) having a thickness of about 25 μm. When an overcurrent flows, the separator 103 generates pores due to heat generation. Has a function of blocking the current.

  The separator of the present invention is not limited to a single-layer film such as polyolefin, but a three-layer structure in which a polypropylene film is sandwiched with a polyethylene film, or a laminate of a polyolefin microporous film and an organic nonwoven fabric can also be used. By making the separator into multiple layers, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (rigidity improvement) function can be provided.

As shown in FIGS. 2 and 3, the electrode laminate 101 described above has the positive electrode plates 102 and the negative electrode plates 104 alternately laminated via the separators 103, and the separators 103 are provided on the uppermost layer and the lowermost layer. As shown in FIG. 1, each has a width W ₁ as a whole. The three positive plates 102 are respectively connected to the positive terminal 105 made of metal foil via the positive current collector 102a, while the three negative plates 104 are connected to the negative current collector 104a. To the negative electrode terminal 106 made of metal foil.

The positive electrode plate 102, the separator 103, and the negative electrode plate 104 of the electrode laminate 101 are not limited to the above number in the present invention. For example, one positive electrode plate 102, three separators 103, and The electrode laminate 101 can also be configured with a single negative electrode plate 104, and the number of positive electrode plates, separators, and negative electrode plates can be selected as necessary. The width W ₁ of the electrode stack 101, the capacity and the positive electrode plate is required to the secondary battery, it is set according to the number of sheets of separators and the negative electrode plate.

  The positive electrode terminal 105 and the negative electrode terminal 106 are not particularly limited as long as they are electrochemically stable metal foils. Examples of the positive electrode terminal 105 include an aluminum foil having a thickness of about 0.2 mm, an aluminum alloy foil, a copper foil, or And nickel foil. Examples of the negative electrode terminal 106 include a nickel foil, a copper foil, a stainless steel foil, or an iron foil having a thickness of about 0.2 mm. These metals are suitable as a constituent element of a secondary battery in terms of the resistance value, linear expansion coefficient, and resistivity of the metal, and particularly can suppress the stress accompanying expansion due to heat generation in the secondary battery. This is particularly effective for a thin secondary battery as in this embodiment.

Furthermore, the positive terminal 105 of the secondary battery 10 according to the present embodiment, as shown in FIG. 4, the second portion 105b of the first portion 105a and a narrower width _{W 3} than the width _{W 2} of width _{W 2} (W ₂ > W ₃ ), and has a convex outer shape as a whole. As shown in FIG. 1, the width W ₂ of the first portion 105a of the positive electrode terminal 105 is substantially the same as the width W ₁ of the electrode stack 101 (W ₂ = W ₁ ). Further, as shown in FIG. 3, the first portion 105 a of the positive electrode terminal 105 is formed in the space formed by the exterior members 107 and 108 when the positive electrode terminal 105 is sealed by the exterior members 107 and 108. A positive current collector 102 a located and extending from the electrode laminate 101 is connected. On the other hand, the second portion 105b is a portion other than the first portion 105a, is thermally fused to the exterior members 107 and 108, and is further led out from the exterior members 107 and 108.

Similarly, negative terminal 106, a second portion of Figure 4 as shown in, the first portion 106a and a narrower width _{W 3} than the width _{W 2} of width _{W 2} of the secondary battery 10 according to this embodiment 106b (W ₂ > W ₃ ), and has a convex outer shape as a whole. As shown in FIG. 1, the width W ₂ of the first portion 106a of the negative electrode terminal 106 is substantially the same as the width W ₁ of the electrode stack 101 (W ₂ = W ₁ ). Further, the first portion 106 a of the negative electrode terminal 106 is located in a space formed by the exterior members 107 and 108 when the negative electrode terminal 106 is sealed with the exterior members 107 and 108, and the electrode laminate 101. The negative electrode side current collector 104a extending from is connected. On the other hand, the second portion 106b is a portion other than the first portion 106a, is thermally fused to the exterior members 107 and 108, and is further led out from the exterior members 107 and 108.

Thus, in this embodiment, the electrode terminals 105 and 106, a first portion 105a having a width _{W 1} substantially the same width _{W 2} of the electrode stack 101, by including the 105b, the first By connecting the current collectors 102a and 104a of the electrode stack 101 to the portions 105a and 106a, the electrode portions 105a and 106a and the current collectors 102a and 104a are simply overlapped in the width direction. , 106 and the electrode stack 101 in the width direction are restricted, so that it is possible to eliminate variations in the relative position of the electrode stack 101 with respect to the electrode terminals 105, 106. The battery 10 can be arranged with high accuracy.

In addition, if the width of the electrode terminals 105 and 106 is simply increased, heat generation that occurs during charging and discharging of a large current is suppressed, while a sealing portion by the exterior members 107 and 108 increases, and the exterior members 107 and 108 are sealed. Stoppage and insulation may be reduced. In contrast, in the present embodiment, the first portions 105a and 106a of the electrode terminals 105 and 106 are positioned in the space formed inside the exterior members 107 and 108, and the electrode terminals 105 and 106 have the first portions portion 105a, a second portion 105b having a width _{W 3} than the width _{W 2} of 106a, is provided with 106b, the second portion 105b, exterior by positioning and 106b on the outer periphery of the outer member 107 and 108 members 107 , 108 is further heat-sealed, and the second portions 105b and 106b are led out from the outer peripheral edges of the exterior members 107 and 108, thereby maintaining the sealing and insulating properties of the exterior members 107 and 108, It is possible to secure the cross-sectional area of the electrode terminals 105 and 106 necessary for suppressing heat generation.

  In the present embodiment, the metal foil itself constituting the current collectors 102a and 104a of the electrode plates 102 and 104 is extended to the electrode terminals 105 and 106, whereby the electrode plates 102 and 104 are directly connected to the electrode terminals 105 and 106. Although the current collectors 102a and 104a of the electrode plates 102 and 104 and the electrode terminals 105 and 106 are connected by a material or component different from the metal foil constituting the current collectors 102a and 104a. Also good.

  5A is a plan view showing another example of the electrode terminal of the secondary battery shown in FIG. 1, FIG. 5B is a cross-sectional view taken along line VB-VB in FIG. 5A, and FIG. It is an expanded sectional view equivalent to the III-III part of Drawing 1 of a rechargeable battery using the positive electrode terminal shown in Drawing 5 (A) and (B).

As another example of the positive electrode terminal used in the secondary battery according to the present embodiment, the positive electrode terminal 105 ′ has a _first width W ₂ that is substantially the same as the width W ₁ of the electrode stack 101 as described above. 'and a second portion 105b having a width _{W 3} than the width _{W 2'} portion 105a in addition to be provided with a further, as shown in FIG. 5 (a) and (B), first The thickness T ₁ of the _first portion 105a ′ is set to the thickness T of the second portion 105b ′ so that the cross-sectional area of the second portion 105a ′ is substantially equal to the cross-sectional area of the second portion 105b ′. It may be thinner than ₂ (T ₁ <T ₂ ).

Similarly, in the negative terminal, 'the first portion 106a having a width W ₁ substantially the same width W ₂ of the electrode stack 101 as described above' negative terminal 106 and, from the width W ₂ 'in addition to the and a further, as shown in FIG. 5 (a) and (B), the first portion 106a' a second portion 106b having a width W ₃ a cross-sectional area and a second of The thickness T ₁ of the first portion 106 a ′ may be smaller than the thickness T ₂ of the second portion 106 b ′ so that the cross-sectional area of the portion 106 b ′ is substantially the same (T ₁ < T _2).

Thus, in the electrode terminals 105 ′ and 106 ′, the thickness T1 of the _first portions 105a ′ and 106a ′ is made thinner than the thickness T2 of the _second portions 105b ′ and 106b ′ (T ₁ < T ₂ ), by providing a stepped portion between the first portions 105a ′ and 106a ′ and the second portions 105b ′ and 106b ′, the electrode terminals 105 ′ and 106 ′ are gathered together as shown in FIG. When connecting the electric bodies 102a and 104a, the positions of the electrode terminals 105 ′ and 106 ′ and the electrode laminate 101 in the length direction are simply adjusted by aligning the ends of the current collectors 102a and 104a with the stepped portions. Since the relationship can be restricted, it is possible to eliminate variations in the relative positional relationship of the electrode laminate 101 with respect to the electrode terminals 105 ′ and 106 ′, and the secondary battery 10 can be arranged with high accuracy when forming an assembled battery. It becomes possible.

The electrode terminals 105 ', 106' in a first portion 105a having a width _{W 2} ', 106a' of the thickness _{T 1} of the second portion 105b having a width _{W 3} than the width _{W 2} ', 106b This electrode is made thinner than the thickness T ₂ by making the cross-sectional area of the first portions 105a 'and 106a' substantially the same as the cross-sectional area of the second portions 105b 'and 106b'. The resistances at the terminals 105 ′ and 106 ′ are substantially uniform, and heat generation when a current flows through the electrode terminals 105 ′ and 106 ′ can be suppressed.

  The electrode laminate 101 configured as described above is housed and sealed in the upper exterior member 107 and the lower exterior member 108 (sealing means). As shown in FIG. 1, the upper exterior member 107 in the present embodiment has a cup shape in which the outer shape is provided with a convex portion that accommodates the electrode laminate 101. As shown in FIG. 3, the secondary battery 10. From the inside to the outside, three layers 107a to 107c are stacked in the order of the first resin layer 107a, the metal layer 107b, and the third resin layer 107c. All of these three layers 107 a to 107 c are laminated over the entire surface of the upper exterior member 107.

  The first resin layer 107a of the upper exterior member 107 is a resin film excellent in electrolytic solution resistance and heat fusion property such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer. The metal layer 107b of the upper exterior member 107 is, for example, a metal foil such as an aluminum foil. The second resin layer 107c of the upper exterior member 107 is a resin film excellent in electrical insulation, such as a polyamide-based resin or a polyester-based resin. Therefore, the upper exterior member 107 is formed by laminating one surface of the metal foil (inner side surface of the secondary battery) with a material excellent in electrolytic solution resistance and heat fusion, and the other surface (outside of the secondary battery). For example, a flexible resin-metal thin film laminate material having a thickness of about 125 μm is laminated.

  The lower exterior member 108 has a flat plate shape as shown in FIG. 2 and has the same layer structure as the upper exterior member 107. As shown in FIG. From the inside to the outside, for example, a first resin layer 108a composed of a resin film excellent in electrolytic solution resistance and heat fusion properties such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer A metal layer 108b made of a metal foil such as an aluminum foil, and a second resin layer 108c made of a resin film excellent in electrical insulation such as a polyamide resin or a polyester resin, for example. It has a three-layer structure. Accordingly, the lower exterior member 108 is formed by laminating one surface of the metal foil (inner side surface of the secondary battery) with a material excellent in electrolytic solution resistance and heat fusion, and the other surface (outside of the secondary battery). For example, a flexible resin-metal thin film laminate material having a thickness of about 125 μm is laminated.

  Furthermore, in the embodiment, in order to maintain the sealing performance in the secondary battery 10, a seal film 109 (sealing means) is interposed at a portion where the positive electrode terminal 105 and the exterior members 107 and 108 are in contact with each other. Yes. Similarly, the negative electrode terminal 106 is led out from the other end portion of the exterior members 107 and 108, and here, similarly to the positive electrode terminal 105 side, the negative electrode terminal 106 and the exterior members 107 and 108 are in contact with each other. A seal film 109 is interposed between the two. Examples of the material constituting the seal film 109 include polyethylene, modified polyethylene, polypropylene, modified polypropylene, or synthetic resin materials excellent in electrolytic solution resistance and heat fusion properties such as ionomer. It is preferable that the first resin layers 107a and 108a of the members 107 and 108 are made of the same material.

  In this way, the first resin layers 107a and 108a and the seal film 109 of the exterior members 107 and 108 are made of a synthetic resin material such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer. As a result, it is possible to ensure good fusion with the metal electrode terminal. In addition, since the exterior member includes a metal layer in addition to the resin layer, it is possible to improve the strength of the exterior member itself.

  Further, when the seal film 109 is interposed at the contact portion between the exterior members 107 and 107 and the electrode terminals 105 and 106 as in this embodiment, if the width of the electrode terminals 105 and 106 is simply increased, the seal film The exposed area of the end face 109 increases, and there is a tendency for moisture to enter the secondary battery 10 from the end face and to dissipate volatile components of the electrolytic solution from the inside of the secondary battery 10. On the other hand, in this embodiment, the second portions 105b and 106, which are narrow in the electrode terminals 105 and 106, are positioned on the outer peripheral edge of the exterior members 107 and 108, and the exterior members 107 and 108 are heat-sealed. Since the second portions 105b and 106b are led out from the exterior members 107 and 108, the exposed area of the end surface of the seal film 109 is reduced, and it is possible to prevent the ingress of moisture and the dissipation of volatile components of the electrolyte. It is possible.

  The number of layers constituting the exterior member is not limited to the above, and the required number of layers can be set as appropriate. Further, in this embodiment, the upper exterior member 106 and the flat lower exterior member 107 that are preliminarily formed into a convex shape are used as the exterior members. However, the present invention is not particularly limited to this. You may use what was shape | molded in the shape for an upper exterior member and a lower exterior member. Furthermore, in the present embodiment, a seal film is interposed between the exterior members 107 and 108 and the electrode terminals 105 and 106. However, the present invention is not particularly limited thereto, for example, without interposing a seal film, The first resin layer of the exterior member may be heat-sealed to the electrode terminal to directly seal the electrode terminal, or a seal film may be included in the exterior member in advance. Further, in the present embodiment, as shown in FIG. 1, the positive electrode terminal 105 and the negative electrode terminal 106 are led out from the short sides facing the exterior members 107 and 108 of the secondary battery 10, respectively. For example, the positive electrode terminal and the negative electrode terminal may be led out in the same direction from the same short side of the exterior members 107 and 108.

These exterior members 107 and 108 wrap the electrode laminate 101 described above and a part of the electrode terminals 105 and 106, and while injecting a liquid electrolyte into the space formed by the exterior members 107 and 108, After vacuuming the inside of the space, as shown in FIG. 1, the exterior members 107 and 108 are heat-sealed and sealed. Examples of the solute of the liquid electrolyte include lithium salts such as lithium hexafluorophosphate (LiPF ₆ ), lithium perchlorate (LiClO ₄ ), and lithium borofluoride (LiBF ₄ ). Examples of the organic liquid solvent for the liquid electrolyte include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), and dimethyl carbonate (DMC). However, the organic liquid solvent of the present invention is not particularly limited to this, and is an organic solvent prepared by mixing an ester solvent with an ether solvent such as γ-butylactone (γ-BL) or dietoshikitan (DEE) and the like. A liquid solvent can also be used.

  Below, the assembled battery comprised by combining multiple secondary batteries which concern on the above-mentioned embodiment, and the composite assembled battery comprised by combining multiple said assembled batteries are demonstrated.

  7A and 7B are plan views showing a connection structure of a plurality of secondary batteries according to an embodiment of the present invention. FIG. 7A shows parallel connection, and FIG. 7B shows a comparison. 8A and 8B are diagrams showing another connection structure of a plurality of secondary batteries according to the embodiment of the present invention, and FIG. 8A is a parallel connection. FIG. 8B is a diagram showing a series connection for comparison, and FIGS. 9A to 9C are diagrams showing an assembled battery including a plurality of secondary batteries according to the embodiment of the present invention. 9 (A) is a plan view thereof, FIG. 9 (B) is a front view thereof, FIG. 9 (C) is a side view thereof, and FIG. 10 is constituted by a plurality of assembled batteries according to an embodiment of the present invention. 11A is a plan view of the composite assembled battery shown in FIG. 10, FIG. 11B is a front view thereof, FIG. 11C is a side view thereof, and FIG. The combined assembled batteries shown in 10 is a schematic view of the mounting the vehicle.

  First, two types of connection structures that give a strong structure against an external force applied by external vibration or the like when two secondary batteries 10 are electrically connected will be described.

  As shown in FIG. 7A, the first connection structure that provides a structure strong against external force is the positive terminal 105 of the first secondary battery 10a and the positive terminal of the second secondary battery 10b. The first secondary battery 10a and the second secondary battery 10b are juxtaposed on substantially the same plane in such a direction that 105 is led out in the same direction. Then, the positive terminal 105 of the first secondary battery 10a and the positive terminal 105 of the second secondary battery 10b are electrically connected by the first bus bar 21a. Further, the negative terminal 106 of the first secondary battery 10a and the negative terminal 106 of the second secondary battery 10b are electrically connected by the second bus bar 21b. In this way, by connecting the same polarity terminals of the two secondary batteries with the bus bar to form a link structure, an external force due to external vibration or the like is applied to each secondary battery in the same phase. The structure is strong against twisting generated in the secondary battery.

  In contrast, as shown in FIG. 7B, in the direction in which the positive terminal 105 of the first secondary battery 10a and the negative terminal 106 of the second secondary battery 10b are led out in the same direction. The first secondary battery 10a and the second secondary battery 10b are juxtaposed on the same plane, and the positive terminal 105 of the first secondary battery 10a and the negative terminal 106 of the second secondary battery 10b. Without first electrically connecting the negative terminal 106 of the first secondary battery 10a and the positive terminal 105 of the second secondary battery 10b by the second bus bar 21b. In the case where the second secondary batteries 10a and 10b are connected in series, an external force due to external vibration or the like is independently applied to each secondary battery because of the non-link structure. Compared to the case, the structure is weak against twisting.

  As shown in FIG. 8A, the second connection structure is such that the positive terminal 105 of the first secondary battery 10a and the positive terminal of the second secondary battery 10b are led out in the same direction. In the direction, the second secondary battery 10b is stacked on the first secondary battery 10a. Then, the positive terminal 105 of the first secondary battery 10a and the positive terminal 105 of the second secondary battery 10b are welded and electrically connected. Similarly, the negative terminal 106 of the first secondary battery 10a. And the negative electrode terminal 106 of the second secondary battery 10b are welded and electrically connected. In this way, by connecting the same polarity terminals of two secondary batteries to form a link structure, an external force due to external vibration or the like is applied to each secondary battery in the same phase. The structure is strong against twisting.

  In contrast, as shown in FIG. 8B, in the direction in which the positive terminal 105 of the first secondary battery 10a and the negative terminal 106 of the second secondary battery 10b are led out in the same direction. The second secondary battery 10b is stacked on the first secondary battery 10a, and the positive terminal 105 of the first secondary battery 10a and the negative terminal 106 of the second secondary battery 10b are electrically connected. Without connecting, the negative electrode terminal 106 of the first secondary battery 10a and the positive electrode terminal 105 of the second secondary battery 10b are welded and electrically connected. The external force due to the vibrations is applied to each secondary battery independently, and the structure is weak against twisting compared to the case of the parallel connection described above.

  FIGS. 9A to 9C show an assembled battery 20 including, for example, 24 secondary batteries 10 connected in parallel using the above-described two connection structures. The assembled battery 20 includes 24 secondary batteries 10, assembled battery terminals 22 and 23, and an assembled battery cover 25. Although not particularly illustrated, the electrode terminals 105 and 106 of each secondary battery 10 are connected in parallel by the bus bars 21a and 21b according to the connection structure described above, and further, the first terminals for connecting the positive terminals 105 are connected. The bus bar 21a is connected to an assembled battery terminal 22 led out from the assembled battery cover 25. Similarly, the second bus bar 21 b connecting each negative electrode terminal 106 is connected to the assembled battery terminal 23 led out from the assembled battery cover 25. Twenty-four secondary batteries 10 connected in this manner are accommodated in the assembled battery cover 25 and formed between the cover 25 of the assembled battery 20 and other components of the assembled battery 20. The space is filled with a filler 24 and sealed. Further, when the assembled battery 20 is stacked as a composite assembled battery, which will be described later, in order to reduce the transmission of vibration between the assembled batteries 20 as much as possible, the external elastic bodies 26 are attached to the lower four corners of the assembled battery cover 25. ing.

  10 and 11 (A) to (C) show a composite assembled battery 30 including six assembled batteries 20 electrically connected to the assembled battery 20 shown in FIGS. 9 (A) to (C). . As shown in FIGS. 10 and 11A to 11C, the composite battery pack 30 is laminated so that the terminals 22 and 23 of the battery pack face each other in the same direction. That is, the terminals 22 and 23 of the assembled battery 20 located at the m-th stage and the terminals 22 and 23 of the assembled battery 20 located at the (m + 1) -th stage are oriented in the same direction. In addition, the assembled battery 20 at the (m + 1) th stage is stacked (m: natural number). The assembled battery positive terminals 22 of all the assembled batteries 20 facing in the same direction are electrically connected to the external connection positive terminal 31 that connects the composite assembled battery 30 to the outside. Similarly, the assembled battery negative terminals 23 of all assembled batteries 20 facing in the same direction are electrically connected to the external connection negative terminal 32. As shown in the figure, the external connection positive electrode terminal 31 has a substantially rectangular flat plate shape, and a plurality of terminal connection holes having a diameter into which the assembled battery positive electrode terminal 22 can be inserted or press-fitted are processed. ing. The terminal connection holes are processed at a pitch substantially equal to the pitch between the assembled battery positive terminals 22 of the stacked assembled battery 20, and the same terminal connection holes are formed in the external connection negative terminal 32. Has been processed. The six assembled batteries 20 stacked as described above are connected to the side surfaces of the both sides by flat connecting members 34 and further fastened by fixing screws 35.

  As described above, an assembled battery is configured with a predetermined number of secondary batteries as a unit, and further, a composite assembled battery is configured with the assembled battery as a unit, so that a composite assembled battery suitable for the required capacity, voltage, etc. Can be easily obtained.

  In addition, since the composite assembled battery can be configured without complicated connection, the failure rate of the composite assembled battery due to poor connection or the like can be reduced.

  Furthermore, if some of the secondary batteries that make up the composite battery pack fail or deteriorate, and the secondary battery needs to be replaced, replace only the battery pack that incorporates the secondary battery that has failed. This makes it possible to easily repair the composite battery pack.

  FIG. 12 is a schematic diagram illustrating an example in which the above-described composite assembled battery 30 is mounted under the floor of the vehicle 1 such as an electric vehicle. As described above, it is particularly effective to use an assembled battery or a composite assembled battery having a low failure rate and excellent ease of replacement as described above for a vehicle such as an electric vehicle to which a relatively large amount of vibration is applied from the outside.

  As described above, in the present embodiment, the electrode terminal of the secondary battery is provided with the first portion having substantially the same width as the electrode laminate, and the first portion is connected to the electrode laminate. By doing so, the positional relationship in the width direction between the electrode terminal and the electrode laminate is restricted only by overlapping the first portion and the electrode laminate in the width direction. It is possible to eliminate variations in positional relationship, and it is possible to arrange the secondary battery with high accuracy when forming an assembled battery.

  In addition, when the width of the electrode terminal is simply widened, heat generation that occurs during charging / discharging of a large current is suppressed, while the sealing portion by the exterior member increases, and the sealing performance and insulation of the exterior member decrease. However, the first portion of the electrode terminal is positioned in the space formed inside the exterior member, and the electrode terminal is provided with a second portion having a narrower width than the first portion. The outer member is positioned on the outer periphery of the exterior member to seal the exterior member, and the second portion is led out from the outer periphery of the exterior member, thereby maintaining the sealing and insulating properties of the exterior member. At the same time, it is possible to ensure the cross-sectional area of the electrode terminal necessary for suppressing heat generation.

  Furthermore, when the seal film is interposed in the contact portion between the exterior member and the electrode terminal, if the width of the electrode terminal is simply increased, the exposed area of the end face of the seal film increases, and the end face enters the secondary battery from the end face. However, in this embodiment, the narrow second portion of the electrode terminal is used as the outer peripheral edge of the exterior member. Since the exterior member is positioned and sealed, and the second part is led out from the exterior member, the exposed area of the end face of the seal film is reduced, and the ingress of moisture and the dissipation of volatile components of the electrolyte are reduced. It is possible to prevent.

  In the present embodiment, in the electrode terminal, the thickness of the first portion is made thinner than the thickness of the second portion, and a step portion is provided between the first portion and the second portion. When connecting the electrode terminal and the electrode laminate, the positional relationship in the length direction between the electrode terminal and the electrode laminate can be regulated only by aligning the end of the electrode laminate with the stepped portion. Therefore, it is possible to eliminate variations in the relative positional relationship of the electrode laminate with respect to the electrode terminals, and it is possible to arrange the secondary battery with high accuracy when forming an assembled battery.

  Further, in the present embodiment, in the electrode terminal, the thickness of the first portion is made thinner than the thickness of the second portion having a width narrower than the width of the first portion, and the cross-sectional area of the first portion is By making the cross-sectional area of the second portion substantially the same, the resistance at this electrode terminal becomes substantially uniform, and it becomes possible to suppress heat generation when a current flows through the electrode terminal. .

The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

FIG. 1 is a plan view of an entire secondary battery according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is an enlarged cross-sectional view of a portion III in FIG. 4 is a plan view showing an example of an electrode terminal of the secondary battery shown in FIG. 5A is a plan view showing another example of the electrode terminal of the secondary battery shown in FIG. 1, and FIG. 5B is a cross-sectional view taken along the line VB-VB in FIG. 5A. is there. 6 is an enlarged cross-sectional view corresponding to the III part of FIG. 1 of the secondary battery using the positive terminal shown in FIGS. 5 (A) and 5 (B). 7A and 7B are plan views showing a connection structure of a plurality of secondary batteries according to an embodiment of the present invention. FIG. 7A shows parallel connection, and FIG. It is a figure which shows the serial connection for a comparison. FIGS. 8A and 8B are diagrams showing another connection structure of a plurality of secondary batteries according to the embodiment of the present invention. FIG. 8A shows parallel connection, and FIG. FIG. 3 is a diagram showing a series connection for comparison. 9A to 9C are views showing an assembled battery including a plurality of secondary batteries according to the embodiment of the present invention. FIG. 9A is a plan view thereof, and FIG. B) is a front view thereof, and FIG. 9C is a side view thereof. FIG. 10 is a perspective view of a composite assembled battery including a plurality of assembled batteries according to an embodiment of the present invention. 11A is a plan view of the composite assembled battery shown in FIG. 10, FIG. 11B is a front view thereof, and FIG. 11C is a side view thereof. FIG. 12 is a schematic diagram of a vehicle on which the composite battery pack shown in FIG. 10 is mounted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle 10 ... Secondary battery 101 ... Electrode laminated body 102 ... Positive electrode plate 102a ... Positive electrode side collector 102b ... Positive electrode layer 103 ... Separator 104 ... Negative electrode plate 104a ... Negative electrode side collector 104b ... Negative electrode layer 105 ... Positive electrode terminal 105a ... 1st part 105b ... 2nd part 106 ... Negative electrode terminal 106a ... 1st part 106b ... 2nd part 107 ... Upper exterior member 108 ... Lower exterior member 109 ... Seal film 20 ... Assembly battery 30 ... Composite assembly Battery W _1, electrode stack width W _2, first portion width W _3, second portion width

Claims (11)

An electrode laminate having positive and negative plates laminated alternately via separators;
An electrode terminal connected to the electrode laminate;
And a sealing means in which the electrode laminate and the electrode terminal are accommodated in a space formed inside to seal the outer peripheral edge and a part of the electrode terminal is led out from the outer peripheral edge. A battery,
The electrode terminal is
A first portion having substantially the same width as the electrode stack;
A second portion having a narrower width than the first portion,
The first portion of the electrode terminal is located in a space formed inside the sealing means, and the electrode stack is connected,
A secondary battery in which the second portion of the electrode terminal is located at the outer peripheral edge of the sealing means, is sealed by the sealing means, and is led out from the outer peripheral edge of the sealing means.   The secondary battery according to claim 1, wherein the first portion of the electrode terminal is formed thinner than the second portion.   The secondary battery according to claim 1, wherein the first portion and the second portion of the electrode terminal have substantially the same cross-sectional area.   The secondary electrode according to claim 1, wherein the electrode terminal includes one or more components selected from the group consisting of aluminum, iron, copper, and nickel.   The secondary battery according to claim 1, wherein the sealing means includes one or more components selected from the group consisting of polypropylene, modified polypropylene, polyethylene, modified polyethylene, and ionomer.   The positive electrode plate of the electrode laminate has a positive electrode active material comprising a lithium-manganese composite oxide, a lithium-nickel composite oxide, or a lithium-cobalt composite oxide. The secondary battery as described.   The secondary battery according to claim 1, wherein the negative electrode plate of the electrode laminate has a negative electrode active material made of a crystalline carbon material or an amorphous carbon material. An assembled battery having a plurality of the secondary batteries according to claim 1,
The other secondary battery is placed on the one secondary battery so that the electrode terminal of the one secondary battery and the same polarity terminal of the other secondary battery are in substantially the same direction. Laminated,
An assembled battery including at least two or more secondary batteries in which the same polarity terminals of the one secondary battery and the other secondary battery are electrically connected. An assembled battery having a plurality of the secondary batteries according to claim 1,
The other secondary battery is located on the side of the one secondary battery so that the electrode terminal of the one secondary battery and the same polarity terminal of the other secondary battery are in substantially the same direction. Juxtaposed,
An assembled battery including at least two or more secondary batteries in which the same polarity terminals of the one secondary battery and the other secondary battery are electrically connected to each other through a connecting means. A composite assembled battery having a plurality of assembled batteries according to claim 8 or 9,
A composite assembled battery including at least two or more assembled batteries in which one assembled battery and the other assembled battery are electrically connected in parallel and / or in series.   A vehicle equipped with the assembled battery according to claim 8 or 9, or the composite assembled battery according to claim 10.

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