TWI493767B - External cladding for a laminate battery, method for manufacturing an external cladding for a laminate battery, method for manufacturing a laminate battery and laminate battery - Google Patents

Description

External material of laminated battery, method for producing exterior material of laminated battery, method for manufacturing laminated battery, and laminated battery

The present invention relates to an exterior material of a laminated battery, a method of manufacturing an exterior material of a laminated battery, a method of manufacturing a laminated battery, and a laminated battery, and more particularly to externally mounting a tab before clamping it The material forms a step processing portion conforming to the cross-sectional shape of the tab of the position to be sandwiched between the outer members, thereby avoiding a gap between the outer member and the tab, and more reliably securing the battery case A novel improvement in sealing.

In recent years, as a form of a secondary battery such as a lithium battery, a laminated battery in which a battery element is sealed by an exterior material (laminate sheet) is attracting attention. The configuration of such a laminated battery is, for example, those described in Patent Documents 1 and 2 below.

Patent Document 1 discloses a method of manufacturing a laminated battery using a pair of aluminum sheets provided with a resin layer as an exterior material, and a tab attached to the battery element (positive When the electrode and the lead terminal of the negative electrode are disposed between the exterior materials, the outer casing is pressed while the outer casing is pressed (heat sealing step), whereby the resin layers of the outer materials are made to each other. Welding. However, when an aluminum sheet is used as a base material of an exterior material, since aluminum is a soft metal, there is a problem that the strength is insufficient and it is difficult to withstand use for a long period of time.

On the other hand, Patent Document 2 discloses a method of manufacturing a laminated battery by the same method as that of Patent Document 1 described above, using an exterior material made of a stainless steel plate as a base material. According to the configuration of Patent Document 2, by using an exterior material made of a stainless steel plate as a base material, the strength can be improved, and a laminated battery that can be used for a long period of time can be formed.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2002-190283

Patent Document 2: Japanese Laid-Open Patent Publication No. 2006-196217

Here, when an exterior material made of an aluminum sheet as a base material is used as in Patent Document 1, since aluminum is a soft metal, the outer material can be fused into a tab shape by the pressure at the heat sealing step. It also ensures the tightness of the battery case. However, when the outer casing made of stainless steel is used as the patent document 2, since the stainless steel is a hard metal, the shape of the outer material cannot be frozen only by the pressure at the heat sealing step, and it is rebounded. (spring back) and a gap is created between the outer casing and the tab.

In other words, the conventional structure described in Patent Document 2 uses an outer casing made of a stainless steel plate as a base material, and the surface of the outer casing is along the tab by the pressure at the heat sealing step. Since the shape is deformed in a manner, a gap is formed between the exterior material and the tab, and it is difficult to ensure the sealing property of the battery case.

The present invention has been made in view of the above problems, and an object thereof is to provide an exterior material of a laminated battery which can avoid a gap between an exterior material and a tab and which can more reliably ensure the sealing property of the battery case. A method for producing an exterior material of a laminated battery, a method for producing a laminated battery, and a laminated battery.

The exterior material of the laminated battery of the present invention is composed of a stainless steel plate provided with a resin layer, and is one of two outer materials constituting a battery case for accommodating a battery element, and is to be connected to The battery element is formed by welding the respective resin layers to each other in a state in which the tabs of the battery element are disposed between the other components, and the battery case is formed by being welded to each other before the tabs are clamped; A stepped processing portion of a cross-sectional shape of the tab of the position of the two outer members.

In the method of manufacturing an exterior material of a laminated battery according to the present invention, in a punch and a die for forming a stepped processing portion, a punch side wall surface and a die corresponding to the first step side surface portion are provided The side wall surface is formed such that the clearance between the punch side wall surface and the die side wall surface is wider than the outer material, and the first step side surface portion is formed in a circular arc shape.

In the method for producing a laminated battery according to the present invention, the tabs connected to the battery element are placed in a state in which the first and second outer materials including the one of the resin layers and the stainless steel sheet are provided. The heat seal step of pressing the first and second outer materials against the first and second outer materials is performed, and the tabs are sandwiched between the first and second outer materials. The resin layers of the first and second exterior materials are welded to each other, and the first and second outer casings are fitted before the tabs are sandwiched between the first and second outer materials. The step processing portion of the cross-sectional shape of the tab of the position between the materials is formed in advance in at least one of the first and second outer materials.

The laminated battery of the present invention comprises: a battery case for accommodating a battery element; and first and second exterior materials which are formed of one of a resin layer and a stainless steel plate, and are mutually resin-layered Thermally fused to form a battery case; and a tab connected to the battery element and drawn from the first and second exterior materials to the outside of the battery case; at least one of the first and second outer materials Before the tab is inserted, a stepped portion having a cross-sectional shape conforming to the position of the tab to be sandwiched between the first and second exterior members is formed in advance.

According to the exterior material of the laminated battery of the present invention, the method of manufacturing the laminated battery, and the laminated battery, before the tab is sandwiched, the exterior material is formed in advance to be in a position to be sandwiched between the exterior material. Since the step portion of the cross-sectional shape of the tab is processed, the shape of the stepped portion can be more reliably frozen, and the rebound can be prevented from occurring after the heat sealing step. Thereby, it is possible to avoid a gap between the exterior material and the tab, and it is possible to more surely ensure the sealing property of the battery case.

The form for carrying out the invention will be described below with reference to the drawings.

(Embodiment 1)

Fig. 1 is a perspective view showing a laminated battery according to a first embodiment of the present invention. In the figure, the battery element 1 is housed inside the battery case 2. As is well known, the battery element 1 is a laminate of a positive electrode, a negative electrode, and a separator, and is immersed in an electrolyte. In the battery element 1, a pair of tabs 3 (lead terminals of the positive electrode and the negative electrode) are connected. The tab 3 is led out to the outside of the battery case 2, and is connected to an external power source or an external load (not shown). In the battery case 2, a plurality of mounting holes 4 are provided. The mounting hole 4 is for attaching a laminated battery to an installation target such as an electric car.

2 is an exploded perspective view of the laminated battery of FIG. 1. In the figure, the first exterior material 2a and the second exterior material 2b are used to constitute the battery case 2 shown in Fig. 1. The battery case 2 shown in Fig. 1 is formed by bonding the first and second exterior materials 2a and 2b to each other with the tabs 3 connected to the battery element 1 interposed therebetween.

The first and second exterior materials 2a and 2b are provided with a joint portion 20, a pair of stepped processed portions 21, and a battery element accommodating portion 22. The joint portion 20 is a plan view of substantially the entire outer circumference of the first and second exterior materials 2a and 2b. The joint portion 20 is used to directly bond the first and second exterior materials 2a and 2b to each other.

The step processing unit 21 is a portion that is processed so as to protrude from the joint portion 20 in one of the outer circumferences of the first and second exterior materials 2a and 2b. The stepped portion 21 is provided at a position where the tab 3 is sandwiched when the battery case 2 is formed, and is formed to conform to the cross-sectional shape of the tab 3 to be sandwiched between the first and second exterior members 2a and 2b. . The battery element accommodating portion 22 is a portion that is processed so as to protrude from the joint portion 20 at substantially the center positions of the first and second exterior materials 2a and 2b. The battery element accommodating portion 22 is a space for accommodating the battery element 1 when the battery case 2 is formed. As will be described later, the step processing unit 21 and the battery element accommodating unit 22 are formed in advance before the first and second exterior materials 2a and 2b are sandwiched between the tabs 3 (before the heat sealing step described later). In addition, the shape of the stepped processed portion 21 conforming to the cross-sectional shape of the tab 3 is a shape designed such that a gap is not formed between the stepped processed portion 21 and the tab 3 after the heat sealing step described later is performed.

Next, Fig. 3 is a cross-sectional view of the first and second exterior materials 2a and 2b of Fig. 2 . As shown in the figure, the first and second exterior materials 2a and 2b are provided with a resin layer 6 on the surface of the stainless steel sheet 5 as a base material. The thickness of the stainless steel sheet 5 is about 0.04 to 0.40 mm, and the thickness of the resin layer 6 is about 0.02 to 0.40 mm. Further, the resin layer 6 is made of, for example, polypropylene or polyethylene, and is melted when heated to about 130 to 200 degrees. As is well known, the battery case 2 shown in FIG. 1 is in a state where the tab 3 connected to the battery element 1 is placed between the first and second exterior materials 2a and 2b, and the first and second outer portions are pressed. The materials 2a and 2b are formed by heat-sealing the first and second exterior materials 2a and 2b, and the resin layers 6 of the first and second exterior materials 2a and 2b are welded to each other. Further, in order to impart excellent moldability or chemical resistance to the exterior material, it is preferable to use a stainless steel plate having a lubricating film (not shown) on the surface opposite to the surface on which the resin layer 6 is provided as the stainless steel plate 5. .

Next, Fig. 4 is a perspective view showing the tab 3 of Fig. 2. As shown, in the tab 3, the tab body 30 and the film body 31 are included. The tab body 30 is a strip-shaped metal foil and has a thickness t ₁ along the thickness direction 3a of the tab 3 . Further, the tab body 30 of the positive electrode is made of, for example, aluminum, titanium or silver, and the tab body 30 of the negative electrode is made of, for example, copper, nickel, stainless steel or silver. The thickness direction 3a of the tab 3 is perpendicular to the joint surface formed by the joint portion 20 of the first and second exterior materials 2a and 2b (see Fig. 1).

The film body 31 is formed by adhering a strip-shaped film to the front and back surfaces of the tab body 30 by, for example, one of polypropylene or polyethylene. The film body 31 is disposed at a position to be sandwiched between the first and second exterior materials 2a and 2b, and is formed by the step processing portion 21 between the first and second exterior materials 2a and 2b when the battery case 2 is formed. The resin layer 6 is welded. Further, the film body 31, together with the resin layer 6 of the step processing portion 21, also has insulation for electrically insulating the stainless steel sheet 5 and the tab body 30 between the first and second exterior materials 2a, 2b. The function of the layer.

The film body 31 is provided with a film projecting portion 32 projecting from both ends of the tab body 30 along the width direction 3b of the tab 3 along the width direction 3b of the tab 3. The film projecting portions 32 are formed by bonding the strip-shaped films to each other, and are disposed at the center of the tab body 30 along the thickness direction 3a of the tabs 3. The film projecting portion 32 has a protruding amount t ₂ along the width direction 3b of the tab 3 and a thickness t ₃ along the thickness direction 3a of the tab ₃ . t ₃ /2 is equivalent to the thickness of one part of the strip film. Further, the width direction 3b of the tab 3 is a direction perpendicular to the thickness direction 3a of the tab 3 and the extension direction 3c from which the tab 3 extends from the battery case 2 (see Fig. 1).

Next, Fig. 5 is a cross-sectional view taken along line V-V of Fig. 4, and shows the cross-sectional shape of the tab 3 to be sandwiched between the first and second exterior materials 2a, 2b. As shown in the figure, the cross-sectional shape of the tab 3 to be sandwiched between the first and second outer covering members 2a and 2b is such that the film projecting portion 32 protrudes from both ends of the tab body 30. Set to a simpler shape with a simpler rectangle. Specifically, the tab 3 has a first tab end face 35, a first tab side face 36, and a second tab end face 37 at positions to be sandwiched between the first and second exterior members 2a and 2b. And the second tab side 38.

The first tab end surface 35 is an end surface of the film body 31 extending along the width direction 3b of the tab 3, and is an end surface that covers the entire width of the tab body 30 and overlaps the front surface and the back surface of the tab body 30.

The first tab side surface 36 is an end surface of the film body 31 extending from the end portion of the first tab end surface 35 along both sides in the width direction 3b of the tab 3 along the thickness direction 3a of the tab 3. The first tab side surface 36 is provided on a plane orthogonal to the first tab end surface 35.

The second tab end surface 37 is an end surface of the film projecting portion 32 of the film body 31 extending from the end portion of the first tab side surface 36 along the width direction 3b of the tab 3 . The second tab end surface 37 is provided on a plane orthogonal to the first tab side surface 36.

The second tab side surface 38 is an end surface of the film projecting portion 32 of the film body 31 extending from the end portion of the second tab end surface 37 along the thickness direction 3a of the tab 3 . The second tab side surface 38 is provided on a plane orthogonal to the second tab end surface 37.

In this manner, since the cross-sectional shape of the tab 3 to be sandwiched between the first and second exterior materials 2a and 2b is a complicated shape, the shape of the stepped portion 21 for sandwiching the tab 3 is formed. Also need to be set to take into account the shape of this point.

Next, Fig. 6 is a cross-sectional view of the step processing portion 21 of Fig. 2 . In the figure, the step difference processing portion 21 is provided with a first step end surface portion 210, a first step side surface portion 211, and a connecting portion 212. The first-stage differential end surface portion 210 is a wall extending in the width direction 3b of the tab 3 so as to correspond to the first tab end surface 35 when the step-processing portion 21 is superposed on the tab 3 as shown by a one-dot chain line in the figure. unit. When the stepped processed portion 21 is superposed on the tab 3, the first stepped surface portion 211 is formed from the end portion of the first stepped end surface portion 210 along the tab portion so as to correspond to the first tab side surface 36 (see FIG. 5). a wall portion extending in the thickness direction 3a.

The connecting portion 212 is a wall portion for connecting the end portion of the joint portion 20 and the end portion of the first step side surface portion 211. In the present embodiment, the connecting portion 212 is constituted by the second step end surface portion 212a and the third step side surface portion 212b. When the stepped processed portion 21 is superposed on the tab 3, the second end portion 212a is formed from the end portion of the first stepped side surface portion 211 along the tab 3 so as to correspond to the second tab end surface 37 (see FIG. 5). The wall portion extending in the width direction 3b. The third step side surface portion 212b is a wall portion whose one end is connected to the second step end surface portion 212a and whose other end is connected to the end portion of the joint portion 20, and corresponds to the second pole when the step processing portion 21 is overlapped with the tab 3 The manner of the ear side 38 extends along the thickness direction 3a of the tab 3. Further, when the stepped processed portion 21 is superposed on the tab 3, the joint portion 20 is apart from the end portion of the first stepped side surface portion 211 along the width direction 3b and the thickness direction 3a of the tab 3, and is along the pole. The outer side position of the second tab side surface 38 of the width direction 3b of the ear 3 extends along the width direction 3b of the tab.

The amount of protrusion of the first-stage differential end surface portion 210 with respect to the joint portion 20 is obtained by dividing the total thickness t _{1 of the} tab body 30 and the thickness t ₃ of the two-piece strip film constituting the film body 31 by two. The number of the predetermined adjustment amount α is subtracted from the number, that is, it is set to {(t ₁ + t ₃ )/2} - α. The reason why the amount of protrusion is set to be smaller than (t ₁ + t ₃ )/2 is because the resin layer 6 of the first-stage differential end surface portion 210 (refer to FIG. 2) can be used in the heat sealing step. The film body 31 of the tab 3 is more reliably sealed. Further, although the thickness t ₃ of one portion of the strip-shaped film is about 0.05 to 0.2 mm, the adjustment amount α is an amount less than the thickness t ₃ /2 of one sheet of the strip-shaped film, and is 0.01mm is still a large amount.

The amount of protrusion of the third step side surface portion 212b with respect to the joint portion 20 is subtracted from the number of the thickness of the film projecting portion 32 (the thickness of the two sheets of the strip film constituting the film body 31) t ₃ divided by two. The amount of the predetermined adjustment amount β is set to (t ₃ /2}-β. The reason why the amount of protrusion is set to be smaller than (t ₃ /2) is because the heat sealing step is to be performed. The resin layer 6 (see FIG. 2) of the third step side surface portion 212b and the film body 31 of the tab 3 are more reliably sealed. Further, the adjustment amount β is a thickness t ₃ of one sheet which is not up to the strip film. The amount of /2 is an amount larger than 0.01 mm.

The length of the second end difference surface portion 212a along the width direction 3b of the tab 3 is substantially the same length as the protrusion amount t _{2 of the} film protrusion 32.

Next, Fig. 7 is a flow chart showing a method of manufacturing a laminated battery for manufacturing the laminated battery of Fig. 1. As shown in FIG. 7, in the manufacturing method of the laminated battery of this embodiment, the exterior material manufacturing process S1 and the heat sealing process S2 are included.

The exterior material manufacturing step S1 is a step for producing the first and second exterior materials 2a and 2b, and is a step performed before the heat sealing step S2. In the additional material manufacturing step S1, the first and second portions having the joint portion 20, the pair of stepped processed portions 21, and the battery element accommodating portion 22 are manufactured by press working on the flat plate material. Outer materials 2a, 2b.

In the heat sealing step S2, the first and second exterior materials 2a and 2b are pressed while the tab 3 connected to the battery element 1 is placed between the first and second exterior materials 2a and 2b. The step of heating the first and second exterior materials 2a and 2b. By performing this step, the resin layers 6 of the first and second exterior materials 2a and 2b are welded to each other to form the battery case 2.

That is, in the conventional method, the exterior material in a state in which the step processing portion 21 is not provided is used, and the plate surface of the outer material is deformed along the shape of the tab by the pressure at the heat sealing step. However, in the present embodiment, the step processing portion 21 is formed in advance before the heat sealing step S2 is performed (before the tab 3 is sandwiched between the first and second exterior materials 2a and 2b). Thereby, the shape of the step processing portion 21 can be more reliably frozen, and the rebound can be prevented from occurring after the heat sealing step S2 is performed. Therefore, it is possible to avoid a gap between the exterior materials 2a, 2b and the tabs 3, and it is possible to more surely ensure the sealing property of the battery case 2.

Next, FIG. 8 is a cross-sectional view of the vicinity of the step processing portion 21 when the first and second exterior materials 2a and 2b in which the stepped portion 21 of FIG. 6 is formed is used. FIG. 9 and FIG. 10 are explanatory views showing Comparative Examples 1 and 2 when a stepped processing portion having a shape different from that of the stepped processed portion 21 of FIG. 6 is formed. In addition, (a) of FIG. 8 to FIG. 10 shows the state before heat sealing, and (b) shows the state after heat sealing.

As shown in FIGS. 8(a) and 8(b), when the first and second exterior materials 2a and 2b in which the stepped portion 21 of FIG. 6 is formed are used, the heat sealing step S2 is not performed after the heat sealing step S2 is performed. A gap is formed between the step processing portion 21 and the tab 3 . On the other hand, in Comparative Examples 1 and 2 shown in FIGS. 9 and 10, a gap 10 is generated between the stepped portion and the tab after the heat sealing step S2 is performed.

In the comparative example 1 shown in FIG. 9, the connection portion 212 is omitted from the step processing portion 21 of FIG. 6, that is, the joint portion 20 is directly connected to the end portion of the first step side surface portion 211. In this case, the first and second exterior materials are formed by sandwiching the film projecting portion 32 by the joint portion 20 of the first outer casing 2a and the second outer casing 2b. The joints 20 of 2a, 2b cannot be in contact with each other. Due to this, a gap 10 is formed on the outer side of the film protrusion 32 (the second tab side surface 38). On the other hand, in the stepped portion 21 of FIG. 6 , the end portion of the joint portion 20 and the end portion of the first step side surface portion 211 are connected by the joint portion 212 , and the joint portion 20 is attached to the step portion processing portion 21 . When superimposed on the tab 3, the end portion of the first step side surface portion 211 is apart from the width direction 3b and the thickness direction 3a of the tab 3, and is the second pole from the width direction 3b of the tab 3 The outer side position of the ear side 38 extends along the width direction 3b of the tab 3. By the configuration of the connecting portion 212, the film projection 32 is prevented from being sandwiched by the joint portion 20, and the gap between the film projections 32 on the outside is prevented.

In the comparative example 2 shown in FIG. 10, the first step side surface portion 211 is omitted from the step processing portion 21 of FIG. 6, that is, the end portion of the first step end surface portion 210 and the outer side extending from the film projecting portion 32. The end portion of the joint portion 20 is connected by a joint portion 212 formed of an inclined surface. In the case of this configuration, a large gap 10 is generated between the connecting portion 212 and the film projecting portion 32 from the heat sealing step S2, and the gap 10 cannot be eliminated after the heat sealing step S2. On the other hand, in the step processing unit 21 of FIG. 6 , when the step processing unit 21 is superposed on the tab 3 , the end portion of the first step end surface portion 210 is along the first tab side surface 36 . The first step side surface portion 211 is provided so that the thickness direction 3a of the tab 3 extends. By the configuration of the first step side surface portion 211, a large gap 10 is avoided on both sides of the film protrusion 32 along the thickness direction 3a of the tab 3, and the remaining after the heat sealing step S2 is avoided. This gap is 10.

Next, Fig. 11 is an explanatory view showing a modification of the first and second exterior materials 2a and 2b of Fig. 8. In FIG. 8, the first and second exterior materials 2a and 2b are shown when the film projecting portion 32 is disposed at the center of the tab body 30 along the thickness direction 3a of the tab 3 as shown in FIG. However, there is also a case where the film projection 32 is formed at one end of the tab body 30 along the thickness direction 3a of the tab 3 as shown in FIG. In this case, the step processing unit 21 is provided in any one of the first and second exterior materials 2a and 2b as shown in FIG. In other words, the step processing unit 21 can be provided in at least one of the first and second exterior materials 2a and 2b in accordance with the state of the film protrusion 32.

In addition to the laminated battery 2a and 2b, the method of manufacturing the laminated battery, and the laminated battery, before the tab 3 is sandwiched between the first and second exterior materials 2a and 2b, At least one of the first and second outer casings 2a and 2b is formed with a stepped processing portion 21 that conforms to the cross-sectional shape of the tab 3 to be sandwiched between the first and second outer casings 2a and 2b. Therefore, the shape of the step processing portion 21 can be frozen more reliably, and the rebound can be prevented from occurring after the heat sealing step S2 is performed. Thereby, the gap 10 between the first and second exterior materials 2a and 2b and the tab 3 can be avoided, and the sealing property of the battery case 2 can be surely ensured.

Further, in the step processing unit 21, when the step processing unit 21 is superposed on the tab 3, the first step is extended along the width direction 3b of the tab 3 so as to correspond to the first tab end surface 35. When the stepped processing portion 21 is superposed on the tab 3, the first step is extended from the end portion of the first stepped end surface portion 210 along the thickness direction 3a of the tab 3 so as to correspond to the first tab side surface 36. The side surface portion 211 is connected to the position where the end portion of the first step side surface portion 211 is apart from the width direction 3b and the thickness direction 3a of the tab 3 when the step processing portion 21 is overlapped with the tab 3 The connecting portion 212 of the end portion of the joint portion 20 and the end portion of the first step side surface portion 211 extending along the width direction 3b of the tab 3 along the outer side position of the second tab side surface 38 in the width direction 3b of the tab 3 Therefore, even when the cross-sectional shape of the tab 3 is formed into a more complicated shape by the film projecting portion 32 protruding from both ends of the tab body 30, the first and second exterior materials 2a, 2b can be more reliably avoided. A gap 10 is created between the tabs 3 and the reliability of the battery case 2 can be improved.

Further, in the connection portion 212, when the step processing portion 21 is superposed on the tab 3, the end portion of the first step side surface portion 211 is along the tab 3 so as to correspond to the second tab end surface 37. The second-stage differential end surface portion 212a extending in the width direction 3b; and one end connected to the end portion of the second-stage end surface portion 212a and the other end connected to the end portion of the joint portion 20, and when the step-processing portion 21 is overlapped with the tab 3 Since the third step side surface portion 212b extends along the thickness direction 3a of the tab 3 so as to correspond to the second tab side surface 38, the step processing portion 21 can be adhered to the tab 3 from before the heat sealing step S2 is performed. Further, it is possible to more reliably prevent the gap 10 from being generated between the first and second exterior materials 2a and 2b and the tab 3.

Further, in the first embodiment, the shape of the stepped processing portion 21 is a shape in consideration of the existence of the film projecting portion 32, but the film projecting portion is not provided in the film body, and is to be sandwiched between the outer casing members. When the cross-sectional shape of the tab of the position is a simple quadrangular shape, the stepped processed portion described with reference to Fig. 9 has a shape conforming to the cross-sectional shape of the tab. In this case, it is also possible to prevent the occurrence of springback after the heat sealing step by forming the step processing portion in the outer material before the tab is sandwiched between the outer materials, and to avoid the outer material and the outer material. The generation of the gap between the ears.

(Embodiment 2)

Fig. 12 is a cross-sectional view showing the step processing portion 21 of the laminated battery 2a, 2b provided in the stacked battery of the second embodiment of the present invention. The same or equivalent parts as those of the first embodiment are denoted by the same reference numerals. In Embodiment 1, though already described in paragraph 2 by the difference between the end surface 212 _A difference in paragraph 3 side surface portion 212b form the connection portion 212, but in this second embodiment, shown in Figure 12, by the Department of The two-stage differential end surface portion 212a and the inclined portion 212c constitute a connecting portion 212. The inclined portion 212c is constituted by an inclined surface for connecting the end portion of the second-stage differential end surface portion 212a and the end portion of the joint portion 20.

According to the configuration of the first embodiment (the configuration of FIG. 6), the third step side surface portion 212b bent from the second step end surface portion 212a at a right angle can be formed, so that the step processing portion 21 can be closely contacted before the heat sealing step S2 is performed. In the ear 3 . However, depending on the thickness t _{3 of the} film protrusion 32, the processing of the connecting portion 212 is extremely fine, and even if the third step side surface portion 212b is formed by bending the sheet material at a right angle, it is difficult to freeze the shape. Therefore, in the present embodiment, instead of the third step side surface portion 212b, the inclined portion 212c is provided, whereby the amount of processing of the sheet material can be reduced, and the shape can be more reliably frozen.

Next, FIG. 13 is a cross-sectional view of the vicinity of the step processing portion 21 when the first and second exterior materials 2a and 2b in which the stepped portion 21 of FIG. 12 is formed is used. As shown in FIG. 13(a), in the case of the step processing portion 21 of FIG. 12, in the stage before the heat sealing step S2 is performed, since the corner portion of the film projecting portion 32 abuts against the inclined portion 212c, A gap 10 is created around the film protrusion 32. When the heat sealing step S2 is performed, as shown in FIG. 13(b), the film body 31 is melted and deformed in accordance with the step processing portion 21.

Here, when the joint portions 20 of the first and second exterior materials 2a and 2b are in contact with each other, a line segment for connecting the connection portion 212 of the first and second exterior materials 2a and 2b and the base end of each connection portion 212 is connected. The sectional area of the divided space is smaller than the sectional area of the film protrusion 32. Therefore, the space is filled with the melted film protrusion 32 when the heat sealing step S2 is performed as shown in (b) of FIG. That is, even if the connecting portion 212 is configured by the second-stage differential end surface portion 212a and the inclined portion 212c as shown in FIG. 12, the occurrence of the gap 10 can be avoided, and the sealing property of the battery case 2 can be ensured.

Further, when the heat sealing step S2 is performed, the inclined surface of the inclined portion 212c is pressed against the film projecting portion 32, so that the melt of the film projecting portion 32 is moved toward the inner side in the width direction 3b of the tab 3 pressure. Therefore, most of the melt of the film projecting portion 32 which cannot be accommodated in the space does not enter between the joint portions 20, but is pushed out to the inside or the outside of the battery case 2 in the extending direction 3c of the tab 3 .

Next, Fig. 14 is a cross-sectional view of the punch 15 and the die 16 for forming the step processing portion 21 of Fig. 12. The step processing unit 21 of Fig. 12 is formed by press working using the punch 15 and the die 16 shown in Fig. 14 . In the punch 15 and the die 16, a punch side wall surface 15a and a die side wall surface 16a corresponding to the first step side surface portion 211 are provided. The gap 17 between the punch side wall surface 15a and the die side wall surface 16a is made wider than the thickness of the first and second exterior materials. Therefore, the first step side surface portion 211 is formed in a circular arc shape instead of being bent at a right angle from the first step end surface portion 210.

As shown in the first embodiment, by forming the first step side surface portion 211 from the first step end surface portion 210 at a right angle, it is necessary to set the gap 17 to be thicker than the first and second outer members. Substantially equal values. However, when the gap 17 is set in this manner, in the case where a positional shift occurs between the punch 15 and the die 16, there is a case where the actual gap 17 becomes smaller than the plate thickness. If the gap 17 becomes smaller than the plate thickness, the plate material is sheared by the punch 15 and the die 16, and the outer material may be cracked. Therefore, in the second embodiment, when the exterior materials 2a and 2b are manufactured, the gap 17 is made wider than the thicknesses of the first and second exterior materials 2a and 2b, and the first step is made. The side surface portion 211 is formed in an arc shape in cross section, so that the possibility of cracking in the exterior materials 2a and 2b can be reduced, and the forming yield of the exterior materials 2a and 2b can be improved. The other configuration is the same as that of the first embodiment.

In the exterior materials 2a and 2b of such a laminated battery, when the step portion processed portion 21 is overlapped with the tab 3 in the connection portion 212, the first step surface 37 is provided so as to correspond to the second step surface 37. The second end portion 212a of the end portion of the portion 211 extending along the width direction 3b of the tab 3 and the inclined surface of the end portion of the joint portion 20 and the end portion of the joint portion 20 are connected to each other. Since the inclined portion 212c is formed, even if the thickness t _{3 of the} film projecting portion 32 is small, the shape of the connecting portion 212 can be surely frozen, and the occurrence of springback at the connecting portion 212 can be avoided. Thereby, the gap 10 between the first and second exterior materials 2a and 2b and the tab 3 can be more reliably prevented.

Further, in the exterior materials 2a and 2b of the laminated battery and the method of manufacturing the same, the gap 17 between the punch side wall surface 15a and the die side wall surface 16a is set to be larger than the thickness of the outer material. Since the first step side surface portion 211 is formed in a circular arc shape in cross section, the possibility of occurrence of cracks in the exterior materials 2a and 2b can be reduced, and the forming yield of the exterior materials 2a and 2b can be improved.

(Embodiment 3)

Fig. 15 is a cross-sectional view showing the step processing portion 21 of the laminated battery outer materials 2a and 2b according to the third embodiment of the present invention. The same or equivalent parts as those of the first and second embodiments are denoted by the same reference numerals. In the second embodiment, the second segment end surface portion 212a and the inclined portion 212c constitute the connecting portion 212 (see FIG. 12). However, as shown in FIG. 15, the second step end surface portion 212a may be omitted. The connecting portion 212 is configured by the inclined portion 212c. When the connecting portion 212 is configured only by the inclined portion 212c, the maximum amount of protrusion of the inclined portion 212c with respect to the joint portion 20 is (t ₃ /2)-β. The other configurations are the same as those of the first and second embodiments.

Next, FIG. 16 is a cross-sectional view of the vicinity of the step processing portion 21 when the first and second exterior materials 2a and 2b in which the stepped portion 21 of FIG. 15 is formed is used. As shown in (a) of FIG. 16, a gap 10 has been generated between the inclined portion 212c and the film projecting portion 32 in the stage before the heat sealing step S2 is performed. However, since the maximum amount of protrusion of the inclined portion 212c with respect to the joint portion 20 is (t ₃ /2)-β, the inclined portion 212c of the first exterior member 2a and the inclined portion 212c of the second exterior member 2b are used. The area of the triangle of the two sides is smaller than the sectional area of the film protrusion 32. Therefore, as shown in FIG. 16(b), when the heat sealing is performed, the inclined portions 212c of the first and second exterior materials 2a and 2b have a triangular space of two sides, that is, a film which is melted. The protrusion 32 is filled. That is, even in the step processing portion 21 of the present embodiment, the generation of the gap 10 can be avoided, and the sealing property of the battery case 2 can be ensured.

Further, as described in the second embodiment, most of the melt of the film projecting portion 32 which cannot be accommodated in the space does not enter the joint portion 20, but is pushed out along the extending direction 3c of the tab 3 To the inside or the outside of the battery case 2.

In the exterior materials 2a and 2b of the laminated battery, the connecting portion 212 is an inclined portion 212c formed by an inclined surface for connecting the end portion of the joint portion 20 and the end portion of the first step side surface portion 211. Therefore, even if the thickness t _{3 of the} film protrusion 32 is small, the shape of the connecting portion 212 can be more reliably frozen, and the occurrence of springback at the connecting portion 212 can be avoided. Thereby, the gap 10 between the first and second exterior materials 2a and 2b and the tab 3 can be more reliably prevented.

1. . . Battery component

2. . . Battery case

2a. . . First exterior material

2b. . . Second exterior material

3. . . Ear

3a. . . Thickness direction

3b. . . Width direction

3c. . . Extend direction

4. . . Mounting holes

5. . . Stainless steel plate

6. . . Resin layer

10. . . gap

15. . . shower

15a. . . Punch side wall

16. . . die

16a. . . Die sidewall

17. . . gap

20. . . Joint

twenty one. . . Step processing department

twenty two. . . Battery component housing

30. . . Polar body

31. . . Film body

32. . . Film protrusion

35. . . 1st pole end face

36. . . First tab side

37. . . 2nd pole end face

38. . . 2nd tab side

210. . . 1st section of the face

211. . . The first side of the difference

212. . . Connection

212a. . . 2nd section of the face

212b. . . The third side of the difference

212c. . . Inclined portion

S1. . . Exterior material manufacturing steps

S2. . . Heat sealing step

t ₁ , t ₃ . . . thickness

t ₂ . . . Prominent amount

Fig. 1 is a perspective view showing a laminated battery according to a first embodiment of the present invention.

Fig. 2 is an exploded perspective view of the laminated battery of Fig. 1.

Fig. 3 is a cross-sectional view showing the first and second exterior members of Fig. 2;

Figure 4 is a perspective view showing the tab of Figure 2.

Figure 5 is a cross-sectional view taken along line V-V of Figure 4 .

Fig. 6 is a cross-sectional view showing the stepped portion of Fig. 2;

Fig. 7 is a flow chart showing a method of manufacturing a laminated battery for manufacturing the laminated battery of Fig. 1.

8(a) and 8(b) are cross-sectional views showing the vicinity of the step processing portion when the first and second exterior members of the stepped portion of Fig. 6 are formed.

Figs. 9(a) and 9(b) are explanatory views showing a comparative example 1 in the case where a stepped portion having a shape different from that of the stepped portion of Fig. 6 is formed.

Figs. 10(a) and 10(b) are explanatory views showing a comparative example 2 in the case where a stepped portion having a shape different from that of the stepped portion of Fig. 6 is formed.

Fig. 11 is an explanatory view showing a modification of the first and second exterior members of Fig. 8;

Fig. 12 is a cross-sectional view showing a step processing portion provided in a material other than the laminated battery according to the second embodiment of the present invention.

Figs. 13(a) and 13(b) are cross-sectional views showing the vicinity of the step processing portion when the first and second exterior members of the stepped portion of Fig. 12 are formed.

Figure 14 is a cross-sectional view showing a punch and a die for forming the stepped portion of Figure 12;

Fig. 15 is a cross-sectional view showing a step processing portion provided in a material other than the laminated battery according to the third embodiment of the present invention.

Fig. 16 is a cross-sectional view showing the vicinity of the step processing portion when the first and second exterior members of the stepped portion of Fig. 15 are formed.

1. . . Battery component

2. . . Battery case

3. . . Ear

3a. . . Thickness direction

3b. . . Width direction

3c. . . Extend direction

4. . . Mounting holes

20. . . Joint

Claims (9)

An exterior material of a laminated battery, which is composed of a stainless steel plate (5) provided with a resin layer (6), and is a battery case (2) constituting a battery element (1) One of the off-chip materials, and in a state in which the tabs (3) connected to the battery element (1) are disposed between the other materials and the other, by the respective The resin layers (6) are welded to each other to form the battery case (2); before the tabs (3) are sandwiched, the aforementioned tabs are formed in advance to be sandwiched between the two outer sheets ( 3) A stepped processed portion (21) of a cross-sectional shape. The outer casing of the laminated battery according to claim 1, wherein the tab (3) has a first tab end surface (35) at a position to be sandwiched between the outer casings. Extending along the width direction (3b) of the tab (3); the first tab side (36) is from the end of the first tab end face (35) along the thickness of the tab (3) a direction (3a) extending; a second tab end surface (37) extending from an end portion of the first tab side surface (36) along a width direction (3b) of the tab (3); and a second pole The ear side surface (38) extends from the end portion of the second tab end surface (37) along the thickness direction (3a) of the tab (3), and the step processing portion (21) is provided with: The first-stage differential end surface portion (210) is disposed along the aforesaid tab (3) so as to correspond to the first tab end surface (35) when the step processing portion (21) is overlapped with the tab (3) The width direction (3b) extends; the first step side surface portion (211) is formed so as to correspond to the first tab side surface (36) when the step processing portion (21) is overlapped with the tab (3) From the end of the first-stage differential end face (210) along the thickness of the aforementioned ear (3) a direction (3a) extending; and a connecting portion (212) for connecting an end portion of the joint portion (20) and an end portion of the first step side surface portion (211), the joint portion (20) being attached to the step When the processed portion (21) is overlapped with the tab (3), the end portion of the first step side surface portion (211) is separated from the width direction (3b) and the thickness direction (3a) of the tab (3). The position extends from the outer side of the second tab side surface (38) along the width direction (3b) of the tab (3), and extends along the width direction (3b) of the tab (3). The exterior material of the laminated battery according to claim 2, wherein the connecting portion (212) is provided with a second step end surface portion (212a) which is overlapped with the step processing portion (21) The tab (3) extends from the end of the first step side surface portion (211) along the width direction (3b) of the tab (3) so as to correspond to the second tab end surface (37); And a third step side surface portion (212b), one end of which is connected to an end portion of the second step end surface portion (212a), and the other end of which is connected to an end portion of the joint portion (20), and is in the step processing portion (21) When superimposed on the tab (3), it extends along the thickness direction (3a) of the tab (3) so as to correspond to the second tab side surface (38). The exterior material of the laminated battery according to claim 2, wherein the connecting portion (212) is provided with a second step end surface portion (212a) which is overlapped with the step processing portion (21) The tab (3) extends from the end of the first step side surface portion (211) along the width direction (3b) of the tab (3) so as to correspond to the second tab end surface (37); And an inclined portion (212c) formed by an inclined surface for connecting an end portion of the second step end surface portion (212a) and an end portion of the joint portion (20). The exterior material of the laminated battery according to claim 2, wherein the connecting portion (212) is an end portion for connecting the joint portion (20) and an end portion of the first step side surface portion (211) An inclined portion (212c) formed by the inclined surface of the portion. The exterior material of the laminated battery according to any one of claims 2 to 5, wherein the first step side surface portion (211) is formed in a circular arc shape. A method for producing an exterior material of a laminated battery, which is used for manufacturing an exterior material of a laminated battery according to claim 6 of the patent application, in a punch for forming the aforementioned step processing portion (21) ( 15) and a die (16), a punch side wall surface (15a) corresponding to the first step side surface portion (211) and a die side wall surface (16a) are provided by the punch side wall surface The clearance (17) between the (15a) and the die side wall surface (16a) is set to be wider than the thickness of the outer casing, and the first step side surface portion (211) is formed in a circular arc shape. A method of manufacturing a laminated battery in which a tab (3) connected to a battery element (1) is disposed in a first and a third portion of a stainless steel sheet (5) provided with one of a resin layer (6) In the state between the outer casings (2a, 2b), the first and second outer casings (2a, 2b) are pressed against the first and second outer casings (2a, 2b). a heat seal step of heating the first and second outer casings while sandwiching the tabs (3) between the first and second outer materials (2a, 2b) The resin layers (6) of the materials (2a, 2b) are welded to each other, and the tabs (3) are sandwiched between the first and second outer materials (2a, 2b) before being sandwiched. A stepped processed portion (21) having a cross-sectional shape of the tab (3) at a position between the first and second outer covering members (2a, 2b) is formed in advance on the first and second outer covering members (2a) And 2b) at least one of them. A laminated battery comprising: a battery case (2) for accommodating a battery element (1); and first and second exterior materials (2a, 2b) provided with a resin layer (6) One of the pair of stainless steel sheets (5), and the battery case (2) is formed by thermally fusing the resin layers (6); and the tabs (3) are connected to the battery element (1) And extending from the first and second exterior materials (2a, 2b) toward the outside of the battery case (2), and at least one of the first and second exterior materials (2a, 2b) Before sandwiching the tab (3), a cross-sectional shape of the tab (3) conforming to a position to be sandwiched between the first and second exterior members (2a, 2b) is formed in advance. Step difference processing unit (21).