Battery and method for manufacturing a battery

Abstract

A battery 1 comprises: a first current collector (e.g., positive electrode current collector sheet 21); a charging / discharging body 10 including an electrode tab (e.g., positive electrode tab 11b) laminated on the first current collector (e.g., positive electrode current corrector sheet 21); and a second current collector (e.g., positive electrode ribbon 23) that is laminated on the electrode tab (e.g., positive electrode tab 11b) and that has a greater heat capacity than the electrode tab (e.g., positive electrode tab 11b). The first current collector (e.g., positive electrode current collector sheet 21), the electrode tab (e.g., positive electrode tab 11b), and the second current collector (e.g., positive electrode ribbon 23) are welded.

Description

Technical Field

[0001] The present invention relates to a battery and a method for manufacturing the battery.

Background Art

[0002] Conventionally, in a battery, electrical conduction has been achieved by joining an electrode tab of a charge / discharge body and a current collector to each other (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a battery, it is required to sufficiently join an electrode tab of a charge / discharge body and a current collector.

Means for Solving the Problems

[0005] To solve the problems of the above-described conventional technology, the battery of the present invention includes a first current collector, a charge / discharge body including an electrode tab laminated on the first current collector, and a second current collector laminated on the electrode tab and having a larger heat capacity than the electrode tab. The first current collector, the electrode tab, and the second current collector are welded.

[0006] Further, to solve the problems of the above-described conventional technology, the method for manufacturing a battery of the present invention is a method for manufacturing a battery including a first current collector, a charge / discharge body including an electrode tab laminated on the first current collector, and a second current collector laminated on the electrode tab and having a larger heat capacity than the electrode tab. The method for manufacturing a battery includes a step of welding the first current collector, the electrode tab, and the second current collector.

Effects of the Invention

[0007] According to the battery of the present invention, the electrode tabs of the charge / discharge unit and the current collector can be sufficiently joined. Furthermore, according to the manufacturing method of the battery of the present invention, welding defects between the electrode tabs of the charge / discharge unit and the current collector can be suppressed, thereby improving the productivity and yield of the battery. [Brief explanation of the drawing]

[0008] [Figure 1] A perspective view showing battery 1 of the first embodiment. [Figure 2] A cross-sectional perspective view showing the area around the negative terminal 42 of the battery 1 in the first embodiment. [Figure 3] A cross-sectional view showing the area around the negative terminal 42 of the battery 1 in the first embodiment. [Figure 4] A cross-sectional perspective view showing the area around the positive terminal 41 of the battery 1 in the first embodiment. [Figure 5] A cross-sectional view showing the area around the positive terminal 41 of the battery 1 in the first embodiment. [Figure 6] An exploded perspective view showing battery 1 of the first embodiment. [Figure 7] A perspective view showing the charge / discharge body 10 of the battery 1 according to the first embodiment, with the portion of the charge / discharge body 10 including the positive electrode tab 11b and the negative electrode tab 12b removed from the charge / discharge body 10 and shown below. [Figure 8] A cross-sectional view showing a part of the charge / discharge element 10 of the battery 1 of the first embodiment. [Figure 9] A cross-sectional view showing a part of the charge / discharge body 110 of a modified example of the battery 1 of the first embodiment. [Figure 10] A perspective view showing the area around the negative electrode current collector plate 22 of the battery 1 in the first embodiment. [Figure 11] A perspective view showing the area around the positive electrode current collector plate 21 of the battery 1 in the first embodiment. [Figure 12] A cross-sectional view showing the area around the positive electrode current collector plate 21 of the battery 1 in the first embodiment. [Figure 13] An exploded perspective view showing the area around the negative terminal 42 of the battery 1 in the first embodiment. [Figure 14] An exploded perspective view showing the lid 52 and sealing plug 53 of the battery 1 in the first embodiment. [Figure 15]Exploded perspective view showing the vicinity of the positive electrode terminal 41 of the battery 1 of the first embodiment. [Figure 16] Perspective view showing the negative electrode current collector plate 22, the negative electrode tab 12b, the negative electrode ribbon 24, etc. in the manufacture of the battery 1 of the first embodiment. [Figure 17] Perspective view showing the state where the negative electrode current collector plate 22, the negative electrode tab 12b, and the negative electrode ribbon 24 are laminated in the manufacture of the battery 1 of the first embodiment. [Figure 18] Perspective view showing the state where the negative electrode current collector plate 22, the negative electrode tab 12b, and the negative electrode ribbon 24 are laser welded in the manufacture of the battery 1 of the first embodiment. [Figure 19] Perspective view showing a part of the battery 2 of the second embodiment. [Figure 20] Perspective view showing the vicinity of the negative electrode current collector plate 22, the negative electrode tab 212b, and the negative electrode ribbon 24 of the battery 2 of the second embodiment. [Figure 21] Perspective view showing a part of the battery 3 of the third embodiment. [Figure 22] Perspective view showing the vicinity of the negative electrode current collector plate 22, the negative electrode tab 312b, and the negative electrode ribbon 24 of the battery 3 of the third embodiment. [Figure 23] Perspective view showing a part of the battery 4 of the fourth embodiment. [Figure 24] Perspective view showing the vicinity of the negative electrode current collector plate 122, the negative electrode tab 412b, and the negative electrode ribbon 24 of the battery 4 of the fourth embodiment. [[ID=2,9]] [Figure 25] Perspective view showing the vicinity of the negative electrode current collector plate 222 of the battery 5 of the fifth embodiment. [Figure 26] Perspective view showing the vicinity of the positive electrode current collector plate 221 of the battery 5 of the fifth embodiment. [Figure 27] Cross-sectional view showing the vicinity of the positive electrode current collector plate 221 of the battery 5 of the fifth embodiment. [Figure 28] Perspective view showing the negative electrode joint portion 222f of the negative electrode current collector plate 222, the negative electrode tab 12b, the negative electrode ribbon 24, etc. in the manufacture of the battery 5 of the fifth embodiment. [Figure 29] Perspective view showing the state where the negative electrode joint portion 222f of the negative electrode current collector plate 222, the negative electrode tab 12b, and the negative electrode ribbon 24 are laminated in the manufacture of the battery 5 of the fifth embodiment. [Figure 30]A perspective view showing the state in which the negative electrode joint portion 222f of the negative electrode current collector plate 222, the negative electrode tab 12b, and the negative electrode ribbon 24 are laser-welded during the manufacturing of the battery 5 of the fifth embodiment. [Figure 31] A cross-sectional view showing the positive electrode junction 223f of the positive electrode current collector plate 223 of the battery 5 in a modified example 1 of the fifth embodiment. [Figure 32] A cross-sectional view showing the positive electrode junction portion 224f of the positive electrode current collector plate 224 of the battery 5 in a modified example 2 of the fifth embodiment. [Figure 33] A cross-sectional view showing the positive electrode junction 225f of the positive electrode current collector plate 225 of the battery 5 in a modified example 3 of the fifth embodiment. [Figure 34] A perspective view showing the area around the negative electrode current collector plate 222, negative electrode tab 212b (312b), and negative electrode ribbon 24 of the battery 6 of the sixth embodiment. [Figure 35] A perspective view showing the area around the negative electrode current collector plate 322, negative electrode tab 412b, and negative electrode ribbon 24 of the battery 7 of the seventh embodiment. [Modes for carrying out the invention]

[0009] Each embodiment of the present invention will be described with reference to the drawings. In order to facilitate understanding of each embodiment, the size and proportions of the components may be exaggerated in the drawings. In the drawings, the electrode tabs of the charge / discharge body may be shown shorter than their actual length. The electrode tabs shown in Figures 20, 22, and 24 are shown in fewer numbers compared to the electrode tabs shown in the corresponding Figures 19, 21, and 23. The electrode tabs shown in Figures 34 and 35 are also shown in fewer numbers. In each embodiment, the same reference numerals are used for the same components, and redundant explanations are omitted. In each embodiment, a left-handed XYZ Cartesian coordinate system is used, with the X, Y, and Z axes as coordinate axes. The arrows on the X, Y, and Z axes indicate the positive direction of the coordinate axis. The X axis is the coordinate axis in the longitudinal direction of the rectangular battery. The Y axis is the coordinate axis in the short direction of the battery. The Z axis is the coordinate axis in the height direction of the battery. The plane composed of the X and Y axes is called the XY plane, the plane composed of the Y and Z axes is called the YZ plane, and the plane composed of the X and Z axes is called the XZ plane. However, the positional relationships expressed in the XYZ Cartesian coordinate system are merely relative positions.

[0010] [First Embodiment] (Configuration of battery 1 in the first embodiment) The configuration of battery 1 will be explained with reference to Figures 1 to 15.

[0011] Battery 1 includes, for example, a charge / discharge unit 10 for charging and discharging electricity, a current collector 20 connected to the charge / discharge unit 10, a current interrupter 30 connected to the current collector 20, an external terminal 40 connected to the current collector 20 or the current interrupter 30, and an outer casing 50 in which the components of Battery 1 are housed or attached. Battery 1 also includes an insulator 60 that insulates the components of Battery 1 from the outer casing 50, and a sealant 70 that seals the components of Battery 1 from the outer casing 50.

[0012] The charge / discharge unit 10 charges and discharges electricity. The charge / discharge unit 10 shown in Figures 2 to 8 includes a positive electrode 11, a negative electrode 12, a separator 13 (insulating material), and an electrolyte 14. The electrodes (positive electrode 11 and negative electrode 12) are provided with electrode tabs (positive electrode tab 11b and negative electrode tab 12b). As shown in Figure 7, the charge / discharge unit 10 is constructed by winding together components, in which the positive electrode 11 and separator 13 are stacked in that order, into a rectangular shape.

[0013] The positive electrode 11 includes, for example, a long positive electrode current collector layer 11S and a positive electrode active material layer 11T bonded to the positive electrode current collector layer 11S, as shown in Figures 7 and 8. The positive electrode current collector layer 11S includes a current collector portion 11a and a positive electrode tab 11b. The positive electrode active material layer 11T is bonded to the current collector portion 11a. The positive electrode active material layer 11T faces, for example, the entire area along the short direction (Z-axis direction) of the current collector portion 11a.

[0014] The positive electrode tab 11b protrudes from the side edge 11c along the longitudinal direction of the current collector 11a in the short direction of the current collector 11a, as shown, for example, in Figures 7 and 8. The positive electrode tab 11b is formed integrally with the current collector 11a. One positive electrode tab 11b is formed on each current collector 11a. The current collector 11a is formed of, for example, aluminum or an aluminum alloy.

[0015] The positive electrode active material layer 11T contains a positive electrode active material composed of a lithium-containing composite oxide, a binder, and a conductive additive. The lithium-containing composite oxide may include metallic elements such as nickel (Ni), cobalt (Co), and manganese (Mn), along with lithium (Li).

[0016] The negative electrode 12 includes, for example, a long negative electrode current collector layer 12S and a negative electrode active material layer 12T bonded to the negative electrode current collector layer 12S, as shown in Figures 7 and 8. The negative electrode current collector layer 12S includes a current collector portion 12a and a negative electrode tab 12b. The current collector portion 12a of the negative electrode 12 is wider in the short direction (Z-axis direction) compared to the current collector portion 11a of the positive electrode 11. Both ends of the current collector portion 11a of the positive electrode 11 are located within the range of the current collector portion 12a of the negative electrode 12, along the short direction, via a separator 13. The negative electrode active material layer 12T is bonded to the current collector portion 12a. The negative electrode active material layer 12T faces, for example, the entire area of ​​the current collector portion 12a along the short direction.

[0017] The negative electrode tab 12b protrudes from the side edge 12c along the longitudinal direction of the current collector 12a in the short direction of the current collector 12a, as shown in Figures 7 and 8, for example. When stacked with the positive electrode 11 via the separator 13, the negative electrode tab 12b protrudes in the same direction as the positive electrode tab 11b of the positive electrode 11. When stacked with the positive electrode 11 via the separator 13, the negative electrode tab 12b is separated from the positive electrode tab 11b of the positive electrode 11. The negative electrode tab 12b is formed integrally with the current collector 12a. One negative electrode tab 12b is formed on each current collector 12a. The current collector 12a is formed of, for example, copper or a copper alloy.

[0018] The negative electrode active material layer 12T contains a negative electrode active material composed of carbon-based materials, a binder, and a conductive additive. For example, graphite is used as the carbon-based material.

[0019] The separator 13 (insulator) allows lithium ions to pass through while insulating the space between the positive electrode 11 and the negative electrode 12, as shown in Figures 7 and 8, for example. The separator 13 is formed in a long, rectangular shape. The separator 13 has a longer width in the shorter direction (Z-axis direction) compared to the current collector 11a of the positive electrode 11 and the current collector 12a of the negative electrode 12. Both ends of the current collector 11a of the positive electrode 11 and both ends of the current collector 12a of the negative electrode 12 are located within the range of the separator 13 in the shorter direction. The separator 13 is made of a porous material. Polyethylene (PE) or polypropylene (PP) are used for the separator 13. A heat-resistant insulating material may be used instead of the separator 13. For example, ceramics can be used for the heat-resistant insulating material. This configuration is a so-called separatorless configuration.

[0020] Electrolyte 14 corresponds to a so-called electrolyte solution. Electrolyte 14 contains an organic solvent, a supporting salt, and an additive. For example, a carbonate ester is used as the organic solvent. For example, a lithium salt is used as the supporting salt.

[0021] A modified example of the charge / discharge body 10, the charge / discharge body 110, will be described with reference to Figure 9. The configuration of the positive electrode 111 of the charge / discharge body 110 differs from that of the positive electrode 11 of the first embodiment. In the configuration of the charge / discharge body 110, components identical to those of the charge / discharge body 10 are given the same reference numerals and their explanation is omitted. The positive electrode active material layer 111T of the charge / discharge body 110 faces the portion of the current collector 11a excluding both ends along the short direction (Z-axis direction). The heat-resistant insulating layer 111U of the charge / discharge body 110 is bonded to both ends along the short direction of the current collector 11a and to the base end portion of the positive electrode tab 11b. The heat-resistant insulating layer 111U contains, for example, ceramics.

[0022] The current collector 20 is connected to the positive electrode tab 11b and the negative electrode tab 12b of the charge / discharge unit 10. The current collector 20 shown in Figures 2 to 5, 10 to 13 and 15 includes a positive electrode current collector plate 21 (first current collector), a negative electrode current collector plate 22 (first current collector), a positive electrode ribbon 23 (second current collector), and a negative electrode ribbon 24 (second current collector).

[0023] The positive electrode current collector plate 21 (first current collector) connects the positive electrode tab 11b of the charge / discharge body 10 to the positive electrode terminal 41 via a current interrupter 30, as shown in Figures 4 and 5, for example. The positive electrode current collector plate 21 includes a rectangular plate-shaped first base portion 21a, a rectangular plate-shaped second base portion 21b, and a connecting portion 21c that connects the first base portion 21a and the second base portion 21b in a stepped manner with different heights, as shown in Figure 15, for example. A recess 21d is formed on the upper surface (the surface on the positive Z-axis side) of the second base portion 21b, where the thickness of the second base portion 21b is made thinner. A ring-shaped recessed weak portion, the weak portion 21e, is formed in the center of the recess 21d. The first base portion 21a and the positive electrode tab 11b covered by the positive electrode ribbon 23 are laser-welded. The positive electrode current collector plate 21 is made of, for example, aluminum or an aluminum alloy.

[0024] The negative electrode current collector plate 22 (first current collector) connects the negative electrode tab 12b of the charge / discharge body 10 with the negative electrode terminal 42, as shown in Figures 2 and 3, for example. The negative electrode current collector plate 22 includes a rectangular plate-shaped base 22a and an insertion hole 22b that penetrates the base 22a, as shown in Figure 13, for example. The insertion portion 42b of the negative electrode terminal 42 is inserted into the insertion hole 22b of the negative electrode current collector plate 22. The base 22a and the negative electrode tab 12b, which is covered with the negative electrode ribbon 24, are laser-welded. The negative electrode current collector plate 22 is formed of, for example, copper or a copper alloy.

[0025] The positive electrode ribbon 23 (second current collector) is laminated with the positive electrode tab 11b so as to cover it, as shown in Figures 11 and 12, and is laser-welded together with the positive electrode tab 11b and the positive electrode current collector plate 21. The positive electrode ribbon 23 is formed in a rectangular shape along the short side direction (X-axis direction) of the positive electrode tab 11b. The positive electrode ribbon 23 is made of, for example, aluminum or an aluminum alloy.

[0026] The positive electrode ribbon 23 has a greater thickness along the stacking direction (Z-axis direction) than the positive electrode tab 11b. The positive electrode ribbon 23 is made of the same or similar material as the positive electrode tab 11b. Therefore, the specific heat of the positive electrode ribbon 23 is the same or similar as the specific heat of the positive electrode tab 11b. Note that "similar material" refers to alloy materials where the main component material is the same, but the additives are different. Consequently, the welded portion 23g of the positive electrode ribbon 23 has a larger heat capacity than the welded portion 11g of the positive electrode tab 11b. Heat capacity is defined, for example, as the product (multiplied value) of specific heat and volume. Therefore, the positive electrode ribbon 23 is less likely to melt compared to the positive electrode tab 11b.

[0027] The positive electrode ribbon 23 has a thickness along the lamination direction that is thinner than that of the positive electrode current collector plate 21. The positive electrode ribbon 23 is made of the same material as, or a similar material to, the positive electrode current collector plate 21. Therefore, the specific heat of the positive electrode ribbon 23 is the same as or similar to that of the positive electrode current collector plate 21. Consequently, the welded portion 23g of the positive electrode ribbon 23 has a smaller heat capacity than the welded portion 21g of the positive electrode current collector plate 21. For this reason, the positive electrode ribbon 23 melts more easily than the positive electrode current collector plate 21. However, the positive electrode ribbon 23 may be configured to have a thickness along the lamination direction that is thicker than that of the positive electrode current collector plate 21.

[0028] Here, as shown in Figure 12, the positive electrode tab 11b is laminated with the positive electrode current collector plate 21, and the positive electrode ribbon 23 is laminated with the positive electrode tab 11b. In this state, the positive electrode ribbon 23, the positive electrode tab 11b, and the positive electrode current collector plate 21 are laser-welded. Lamination refers to a state in which the positive electrode ribbon 23, the positive electrode tab 11b, and the positive electrode current collector plate 21 are in direct or indirect contact over a certain area, and includes a state in which a part of the positive electrode ribbon 23, a part of the positive electrode tab 11b, and a part of the positive electrode current collector plate 21 are laminated. Specifically, the welded portion 23g of the positive electrode ribbon 23, the welded portion 11g of the positive electrode tab 11b, and the welded portion 21g of the positive electrode current collector plate 21 are laser-welded. In the state in which the positive electrode ribbon 23 is laser-welded with the positive electrode tab 11b and the positive electrode current collector plate 21, the portion of the positive electrode ribbon 23 other than the welded portion 23g is curved and hanging down in the negative Z-axis direction due to its own weight. Similarly, the positive electrode tab 11b is curved and sagging in the negative Z-axis direction due to its own weight, except for the welded portion 11g.

[0029] The positive electrode ribbon 23, positive electrode tab 11b, and positive electrode current collector plate 21 are formed from, for example, aluminum or an aluminum alloy. That is, the positive electrode ribbon 23, positive electrode tab 11b, and positive electrode current collector plate 21 are formed from the same or similar material. If heat capacity is defined, for example, as the product (multiplied value) of specific heat and volume, then if the volume of the welded portion 21g of the positive electrode current collector plate 21 > the volume of the welded portion 23g of the positive electrode ribbon 23 > the volume of the welded portion 11g of the positive electrode tab 11b, then the heat capacity of the positive electrode current collector plate 21 > the heat capacity of the positive electrode ribbon 23 > the heat capacity of the positive electrode tab 11b. In this case, when laser welding is performed from the positive electrode ribbon 23 side, the positive electrode ribbon 23 functions as a cover layer to prevent evaporation of the positive electrode tab 11b, which has a relatively lower heat capacity than the positive electrode ribbon 23. Furthermore, in this case, when laser welding is performed from the side of the positive electrode current collector plate 21, the positive electrode current collector plate 21 functions as a cover layer to prevent evaporation of the positive electrode tab 11b, which has a relatively lower heat capacity than the positive electrode current collector plate 21.

[0030] When the positive electrode ribbon 23, positive electrode tab 11b, and positive electrode current collector plate 21 are laser-welded from the side of the positive electrode ribbon 23, the heat capacity of the welded portion 23g of the positive electrode ribbon 23, shown in the hatched and gray areas of Figure 12, is calculated based on the product of the area of ​​the welded portion 23g (XY plane) and the thickness along the stacking direction (Y axis direction). Similarly, the heat capacity of the welded portion 11g of the positive electrode tab 11b, shown in the hatched and gray areas of Figure 12, is calculated based on the product of the area of ​​the welded portion 11g and the adjacent welded portion 23g (XY plane) and the thickness along the stacking direction (Y axis direction). Similarly, the heat capacity of the welded portion 21g of the positive electrode current collector plate 21, shown in the hatched and gray areas of Figure 12, is calculated based on the product of the area of ​​the welded portion 11g and the adjacent welded portion 23g (XY plane) and the thickness along the stacking direction (Y axis direction). The thickness of the welded portion 21g of the positive electrode current collector plate 21 is calculated by measuring the positive electrode current collector plate 21 at multiple locations along the lamination direction and identifying the parts where the welded portion 21g exists and the parts where the welded portion 21g does not exist.

[0031] The heat capacity can be compared, for example, as follows: the heat capacity of the positive electrode ribbon 23, positive electrode tab 11b, and positive electrode current collector plate 21 over the same area as viewed from the stacking direction is calculated and compared. For example, the heat capacity of the positive electrode tab 11b and positive electrode current collector plate 21 that overlap with the positive electrode ribbon 23 is compared over the same area as viewed from the stacking direction. The area may be the area of ​​the weld, or the area including the weld and its vicinity. The welds of the positive electrode ribbon 23, positive electrode tab 11b, and positive electrode current collector plate 21 are mixed together in the stacked state. Therefore, the specific heat of the positive electrode ribbon 23, positive electrode tab 11b, and positive electrode current collector plate 21 may be calculated based on the material near the weld of each component. That is, the material of the weld of each component and the material near the weld may be considered the same. For example, the specific heat may be calculated based on the material of the portion near each weld that is not affected by the welding. The heat capacity may be calculated based on the total area of ​​the weld and its vicinity. If there are multiple positive electrode tabs 11b, the heat capacity of at least one positive electrode tab 11b is calculated.

[0032] The negative electrode ribbon 24 (second current collector) is laminated with the negative electrode tab 12b so as to cover the negative electrode tab 12b, as shown in Figure 10, and laser-welded together with the negative electrode tab 12b and the negative electrode current collector plate 22. That is, the negative electrode ribbon 24, the negative electrode tab 12b, and the positive electrode current collector plate 21 are laser-welded together in a state where the negative electrode tab 12b is laminated with the negative electrode current collector plate 22 and the negative electrode ribbon 24 is laminated with the negative electrode tab 12b. Here, lamination means, for example, a state in which the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 22 are in direct or indirect contact over a certain area, and includes a state in which a part of the negative electrode ribbon 24, a part of the negative electrode tab 12b, and a part of the negative electrode current collector plate 22 are laminated. The negative electrode ribbon 24 is formed in a rectangular shape along the short side direction (X-axis direction) of the negative electrode tab 12b. The negative electrode ribbon 24 is made of, for example, copper or a copper alloy.

[0033] The negative electrode ribbon 24 has a greater thickness along the stacking direction (Z-axis direction) than the negative electrode tab 12b. The negative electrode ribbon 24 is made of the same or similar material as the negative electrode tab 12b. Therefore, the specific heat of the negative electrode ribbon 24 is the same as or similar to that of the negative electrode tab 12b. Note that "similar material" refers to alloy materials where the main component material is the same, but the additives are different. Consequently, the welded portion of the negative electrode ribbon 24 has a larger heat capacity than the welded portion of the negative electrode tab 12b. For this reason, the negative electrode ribbon 24 is less likely to melt compared to the negative electrode tab 12b.

[0034] The negative electrode ribbon 24 has a thinner thickness along the lamination direction than the negative electrode current collector plate 22. The negative electrode ribbon 24 is made of the same material as the negative electrode current collector plate 22, or a similar material. Therefore, the specific heat of the negative electrode ribbon 24 is the same as or similar to that of the negative electrode current collector plate 22. Consequently, the welded portion of the negative electrode ribbon 24 has a smaller heat capacity than the welded portion of the negative electrode current collector plate 22. For this reason, the negative electrode ribbon 24 melts more easily than the negative electrode current collector plate 22. However, the negative electrode ribbon 24 may be configured to have a thicker thickness along the lamination direction than the negative electrode current collector plate 22.

[0035] The current interrupter 30 is connected to the current collector 20, and makes electrical contact between the current collector 20 and the positive terminal 41. The current interrupter 30 shown in Figures 4, 5 and 15 includes a diaphragm 31, a conductive member 32, and a pair of support bases 33.

[0036] The diaphragm 31 includes, for example, a curved cylindrical body portion 31a, a disc-shaped first joint portion 31b provided on the tip side (negative Z-axis side) of the body portion 31a, and a ring-shaped second joint portion 31c provided on the base side (positive Z-axis side) of the body portion 31a. The first joint portion 31b is joined to the recess 21d of the positive electrode current collector plate 21. The second joint portion 31c is joined to the conductive member 32. The diaphragm 31 is formed of, for example, aluminum or an aluminum alloy.

[0037] The conductive member 32 is formed in a cylindrical shape, as shown in Figure 15, for example. The upper surface (the surface on the positive Z-axis side) of the conductive member 32 is joined to the positive electrode side first insulating plate 62. The periphery of the lower surface (the surface on the negative Z-axis side) of the conductive member 32 is joined to the second joint portion 31c of the diaphragm 31. The conductive member 32 is formed of, for example, aluminum or an aluminum alloy.

[0038] The support base 33 includes, for example, a rectangular main body 33a extending in the short direction (Y-axis direction) of the battery 1, and legs 33b extending downward (negative Z-axis direction) from both sides of the main body 33a in the longitudinal direction (Y-axis direction). One support base 33 is provided at each end of the diaphragm 31 along the longitudinal direction (X-axis direction) of the battery 1. The main body 33a is attached to the positive electrode side first insulating plate 62. The legs 33b are attached to the second base 21b of the positive electrode current collector plate 21. The support base 33 is formed of, for example, an insulating resin.

[0039] The external terminal 40 is connected to the current collector 20 or the current interrupter 30. The external terminal 40 shown in Figures 1 to 6, 10 to 13, and 15 includes a positive terminal 41 and a negative terminal 42.

[0040] The positive terminal 41 is connected to the conductive member 32 of the current interrupter 30, for example, as shown in Figure 5. The positive terminal 41 includes a rectangular plate-shaped base 41a, a cylindrical insertion portion 41b protruding downward (in the negative Z-axis direction) from the base 41a, and a cylindrical joint portion 41c protruding downward (in the negative Z-axis direction) from the periphery of the base 41a.

[0041] The base portion 41a is in contact with the base portion 64a of the positive electrode side second insulating plate 64, for example, as shown in Figure 15. The insertion portion 41b is inserted into the insertion hole 64b of the positive electrode side second insulating plate 64, the positive electrode side insertion hole 52a of the cover 52, the insertion hole 62b of the positive electrode side first insulating plate 62, and the insertion hole 32b of the conductive member 32.

[0042] The joint portion 41c protrudes downward (in the negative Z-axis direction) from the insertion hole 32b of the conductive member 32, as shown in Figure 15, for example, and is expanded radially outward to join with the conductive member 32. That is, the joint portion 41c is crimped to the periphery of the insertion hole 32b of the conductive member 32. Furthermore, the joint portion 41c is welded to the periphery of the insertion hole 32b of the conductive member 32. The positive electrode terminal 41 is formed of, for example, aluminum or an aluminum alloy.

[0043] The negative electrode terminal 42 is connected to the negative electrode current collector plate 22, for example, as shown in Figure 3. The negative electrode terminal 42 includes a rectangular plate-shaped base portion 42a, a cylindrical insertion portion 42b protruding downward (in the negative Z-axis direction) from the base portion 42a, and a cylindrical joint portion 42c protruding downward (in the negative Z-axis direction) from the periphery of the base portion 42a.

[0044] The base portion 42a is in contact with the base portion 65a of the negative electrode side second insulating plate 65, for example, as shown in Figure 13. The insertion portion 42b is inserted into the insertion hole 65b of the negative electrode side second insulating plate 65, the negative electrode side insertion hole 52b of the cover 52, the insertion hole 63b of the negative electrode side first insulating plate 63, and the insertion hole 22b of the negative electrode current collector plate 22.

[0045] The joint portion 42c protrudes downward from the insertion hole 22b of the negative electrode current collector plate 22, as shown in Figure 13, for example, and is expanded radially outward to join with the negative electrode current collector plate 22. That is, the joint portion 42c is crimped to the periphery of the insertion hole 22b of the negative electrode current collector plate 22. Furthermore, the joint portion 42c is welded to the periphery of the insertion hole 22b of the negative electrode current collector plate 22. The negative electrode terminal 42 is formed of, for example, copper or a copper alloy.

[0046] The outer casing 50 houses or mounts the components of the battery 1. The outer casing 50 shown in Figures 1 to 6, 10, 11, and 13 to 15 includes a container 51, a lid 52, and a sealing plug 53.

[0047] The container 51 houses a charge / discharge unit 10 covered by an insulating cover 61, as shown in Figures 2 and 6, for example. The container 51 is made of a rectangular metal can. The container 51 includes an opening 51a that opens along the longitudinal direction and a housing section 51b connected to the opening 51a, as shown in Figure 6, for example. The container 51 is made of aluminum or an aluminum alloy, for example.

[0048] The lid 52 seals the opening 51a of the container 51, as shown in Figures 2 and 6, for example. The lid 52 faces one side 10a (side portion) of the charge / discharge body 10 where the positive electrode 11, separator 13, and negative electrode 12 are adjacent. The lid 52 is formed from a long, plate-shaped metal sheet. The lid 52 has a positive electrode side insertion hole 52a, which is a circular through-hole, at one end in the longitudinal direction. The insertion portion 41b of the positive electrode terminal 41 is inserted into the positive electrode side insertion hole 52a. The lid 52 has a negative electrode side insertion hole 52b, which is a circular through-hole, at the other end in the longitudinal direction. The insertion portion 42b of the negative electrode terminal 42 is inserted into the negative electrode side insertion hole 52b.

[0049] The lid 52 has an injection hole 52c formed by a circular through-hole between the positive electrode side insertion hole 52a and the negative electrode side insertion hole 52b. The electrolyte 14 is injected from the lid 52 toward the container 51 through the injection hole 52c. The insertion portion 53b of the sealing plug 53 is inserted into the injection hole 52c. The lid 52 has a splitting valve 52d formed in the longitudinal center. The lid 52 is welded to the container 51. The lid 52 is made of, for example, aluminum or an aluminum alloy.

[0050] The sealing plug 53 seals the liquid injection hole 52c of the lid 52, for example, as shown in Figure 14. The sealing plug 53 is formed in a cylindrical shape. The sealing plug 53 includes a head 53a with a relatively large outer diameter and an insertion portion 53b that is continuous with the head 53a and has a relatively smaller outer diameter. The head 53a of the sealing plug 53 is welded to the lid 52. The sealing plug 53 is formed of, for example, aluminum or an aluminum alloy.

[0051] The insulator 60 insulates the components of the battery 1 from the outer casing 50. The insulator 60 shown in Figures 2 to 6, 10, 11, 13 and 15 includes an insulating cover 61, a positive electrode side first insulating plate 62, a negative electrode side first insulating plate 63, a positive electrode side second insulating plate 64, and a negative electrode side second insulating plate 65.

[0052] The insulating cover 61 insulates the charge / discharge element 10 by covering it, as shown in Figure 6, for example. The insulating cover 61 includes a pair of opposing sides (first side 61a and second side 61b) and an opening 61c between the first side 61a and the second side 61b that exposes one side 10a of the charge / discharge element 10. The insulating cover 61 covers all sides of the charge / discharge element 10 except for one side of the one side 10a. That is, the insulating cover 61 covers the other side 10b of the charge / discharge element 10 that is opposite to the one side 10a, and the outer periphery 10c located between the one side 10a and the other side 10b of the charge / discharge element 10. The insulating cover 61 is formed in a pentahedral shape by folding a polyhedral sheet into a box shape. The insulating cover 61 is made of, for example, polypropylene.

[0053] The positive electrode side first insulating plate 62 insulates the positive electrode current collector plate 21 and the conductive member 32 from the lid 52, as shown in Figure 5, for example. The positive electrode side first insulating plate 62 includes a rectangular plate-shaped base portion 62a, an insertion hole 62b that penetrates the base portion 62a, and a protrusion 62c that surrounds the side edge of the base portion 62a in an annular shape and protrudes away from the lid 52, as shown in Figure 15, for example. The positive electrode side first insulating plate 62 houses the positive electrode current collector plate 21 and the conductive member 32, etc., in the space formed by the base portion 62a and the protrusion 62c. The insertion portion 41b of the positive electrode terminal 41 is inserted into the insertion hole 62b. The positive electrode side first insulating plate 62 is formed of, for example, an insulating resin.

[0054] The negative electrode side first insulating plate 63 insulates the negative electrode current collector plate 22 from the cover 52, as shown in Figure 3, for example. The negative electrode side first insulating plate 63 includes a rectangular plate-shaped base portion 63a, an insertion hole 63b that penetrates the base portion 63a, and a protrusion 63c that surrounds the side edge of the base portion 63a in an annular shape and protrudes away from the cover 52, as shown in Figure 13, for example. The negative electrode current collector plate 22 is housed in the space formed by the base portion 63a and the protrusion 63c of the negative electrode side first insulating plate 63. The insertion portion 42b of the negative electrode terminal 42 is inserted into the insertion hole 63b. The negative electrode side first insulating plate 63 is formed of, for example, an insulating resin.

[0055] The positive electrode side second insulating plate 64 insulates the positive electrode terminal 41 from the cover 52, as shown in Figure 5, for example. The positive electrode side second insulating plate 64 includes a rectangular plate-shaped base 64a, an insertion hole 64b that penetrates the base 64a, and a protrusion 64c that surrounds the side edge of the base 64a in an annular shape and protrudes away from the cover 52, as shown in Figure 15, for example. The positive electrode terminal 41 is housed in the space formed by the base 64a and the protrusion 64c of the positive electrode side second insulating plate 64. The insertion portion 41b of the positive electrode terminal 41 is inserted into the insertion hole 64b. The positive electrode side second insulating plate 64 is formed of, for example, an insulating resin.

[0056] The negative electrode side second insulating plate 65 insulates the negative electrode terminal 42 from the cover 52, for example, as shown in Figure 3. The negative electrode side second insulating plate 65 includes a rectangular plate-shaped base 65a, an insertion hole 65b that penetrates the base 65a, and a protrusion 65c that surrounds the side edge of the base 65a in an annular shape and protrudes away from the cover 52, for example, as shown in Figure 13. The negative electrode terminal 42 is housed in the space formed by the base 65a and the protrusion 65c of the negative electrode side second insulating plate 65. The insertion portion 42b of the negative electrode terminal 42 is inserted into the insertion hole 65b. The negative electrode side second insulating plate 65 is formed of, for example, an insulating resin.

[0057] The sealing body 70 seals the components of the battery 1 and the outer casing 50. The sealing body 70 shown in Figures 2 to 5, 13 and 15 includes a positive electrode gasket 71 and a negative electrode gasket 72.

[0058] The positive electrode gasket 71 insulates the positive electrode second insulating plate 64 from the lid 52, as shown in Figure 5, for example. The positive electrode gasket 71 is formed in a cylindrical shape. The positive electrode gasket 71 includes a first insertion portion 71a with a relatively large outer diameter, a second insertion portion 71b that is continuous with the first insertion portion 71a and has a relatively smaller outer diameter, and an insertion hole 71c that penetrates the first insertion portion 71a and the second insertion portion 71b, as shown in Figure 15, for example. The first insertion portion 71a of the positive electrode gasket 71 is inserted into the insertion hole 64b of the positive electrode second insulating plate 64. The second insertion portion 71b of the positive electrode gasket 71 is inserted into the positive electrode insertion hole 52a of the lid 52. The insertion portion 41b of the positive electrode terminal 41 is inserted into the insertion hole 71c. The positive electrode gasket 71 is formed of, for example, rubber that has insulating and elastic properties.

[0059] The negative electrode gasket 72 insulates the negative electrode second insulating plate 65 from the lid 52, as shown in Figure 3, for example. The negative electrode gasket 72 is formed in a cylindrical shape. The negative electrode gasket 72 includes a first insertion portion 72a with a relatively large outer diameter, a second insertion portion 72b that is continuous with the first insertion portion 72a and has a relatively smaller outer diameter, and an insertion hole 72c that penetrates the first insertion portion 72a and the second insertion portion 72b, as shown in Figure 13, for example. The first insertion portion 72a of the negative electrode gasket 72 is inserted into the insertion hole 65b of the negative electrode second insulating plate 65. The second insertion portion 72b of the negative electrode gasket 72 is inserted into the negative electrode insertion hole 52b of the lid 52. The insertion portion 42b of the negative electrode terminal 42 is inserted into the insertion hole 72c. The negative electrode gasket 72 is formed of, for example, rubber that has insulating and elastic properties.

[0060] (Method for manufacturing battery 1 of the first embodiment) The manufacturing method of battery 1 will be explained with reference to Figures 16 to 18.

[0061] In the description of the manufacturing method of the battery 1 of the first embodiment, only the manufacturing process specific to the battery 1 will be described, and the description of the manufacturing process similar to that of a general battery will be omitted. Specifically, the manufacturing method of the battery 1 will be described as a method in which a negative electrode tab 12b covered with a negative electrode ribbon 24 is laser-welded to a negative electrode current collector plate 22. The structure of the laser welding on the positive electrode 11 side is the same as the structure of the laser welding on the negative electrode 12 side, so the description will be omitted.

[0062] As shown in Figures 16 to 17, in the first embodiment, the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 22 are stacked. In the first embodiment, the first pressing member 501 and the second pressing member 502 are used to press both ends of the welded portion of the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 22. The first pressing member 501 and the second pressing member 502 are each formed in a rectangular shape and have sufficient rigidity. Specifically, the first pressing member 501 and the second pressing member 502 are made of, for example, metal blocks. The first pressing member 501 and the second pressing member 502 bring the negative electrode ribbon 24 and the negative electrode tab 12b into close contact, and also bring the negative electrode tab 12b and the negative electrode current collector plate 22 into close contact. The negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 22 are stacked in close contact with each other in the space in the Y-axis direction between the first pressing member 501 and the second pressing member 502, with the welded portion of the negative electrode ribbon 24 exposed.

[0063] As shown in Figure 18, in the first embodiment, the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 22 are laser-welded. In the first embodiment, laser light L1 is irradiated from between the first pressing member 501 and the second pressing member 502 toward the negative electrode ribbon 24 to laser-weld the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 22. The welded portion of the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 22 extends along the longitudinal direction (X-axis direction) of the battery 1. Therefore, in the first embodiment, the laser light L1 is scanned in the X-axis direction to continuously laser-weld the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 22. In addition, in the first embodiment, laser welding accompanied by wobbling is performed. In addition, in the first embodiment, the laser light L1 may be scanned in the X-axis direction to intermittently laser-weld the welded portion of the negative electrode tab 12b and the negative electrode current collector plate 22. Subsequently, in the first embodiment, the first pressing member 501 and the second pressing member 502 are retracted from the negative electrode tab 12b.

[0064] (Effects of the battery 1 and the manufacturing method of the battery 1 according to the first embodiment) The effects of the battery 1 and the manufacturing method of the battery 1 according to the first embodiment will be described below. The following mainly describes the effects related to the joining of the positive electrode tab 11b and the positive electrode current collector plate 21. The effects related to the joining of the positive electrode tab 11b and the positive electrode current collector plate 21 are the same as those related to the joining of the negative electrode tab 12b and the negative electrode current collector plate 22.

[0065] As shown in Figure 12, the battery 1 consists of a positive electrode current collector plate 21, a positive electrode tab 11b, and a positive electrode ribbon 23 that covers the positive electrode tab 11b and has a larger heat capacity than the positive electrode tab 11b. These are laminated and, for example, laser-welded. That is, the positive electrode ribbon 23, the positive electrode tab 11b, and the positive electrode current collector plate 21 are, for example, laser-welded together in a state where the positive electrode tab 11b is laminated with the positive electrode current collector plate 21 and the positive electrode ribbon 23 is laminated with the positive electrode tab 11b. The manufacturing method of the battery 1 includes a step of laminating the positive electrode current collector plate 21, the positive electrode tab 11b, and the positive electrode ribbon 23 and laser-welding them. With this configuration of the battery 1, evaporation of the positive electrode tab 11b during laser welding is prevented by the positive electrode ribbon 23, so that the positive electrode tab 11b and the positive electrode current collector plate 21 are sufficiently joined. In this method of manufacturing the battery 1, evaporation of the positive electrode tab 11b during laser welding can be prevented by the positive electrode ribbon 23. This suppresses welding defects between the positive electrode tab 11b and the positive electrode current collector plate 21, thereby improving the productivity and yield of the battery 1.

[0066] Battery 1 may be configured such that the positive electrode current collector plate 21, the positive electrode tab 11b, and the positive electrode ribbon 23 are resistance welded together. With this configuration of battery 1, evaporation of the positive electrode tab 11b during resistance welding is prevented by the positive electrode ribbon 23, so that the positive electrode tab 11b and the positive electrode current collector plate 21 are sufficiently joined. The manufacturing method of battery 1 may include a step of resistance welding the positive electrode current collector plate 21, the positive electrode tab 11b, and the positive electrode ribbon 23. With this manufacturing method of battery 1, evaporation of the positive electrode tab 11b during resistance welding can be prevented by the positive electrode ribbon 23, so that welding defects between the positive electrode tab 11b and the positive electrode current collector plate 21 can be suppressed, and the productivity and yield of battery 1 can be improved.

[0067] In resistance welding, the positive electrode current collector plate 21 and the positive electrode ribbon 23 are sandwiched between a pair of welding electrodes while welding is performed between them. Therefore, the exposure of the welded portion of the positive electrode current collector plate 21 and the positive electrode ribbon 23 is suppressed by the pair of welding electrodes. The positive electrode current collector plate 21 and the positive electrode ribbon 23 are welded by the current input from the pair of welding electrodes. On the other hand, in laser welding, welding is performed between the positive electrode current collector plate 21 and the positive electrode tab 11b and the positive electrode ribbon 23 while at least one side of the positive electrode current collector plate 21 and the positive electrode ribbon 23, i.e., the side irradiated with laser light, is exposed. In other words, resistance welding can suppress evaporation of, for example, the positive electrode ribbon 23 and the positive electrode current collector plate 21 compared to laser welding.

[0068] The following description of the effects of the first embodiment assumes a laser welding configuration, but a resistance welding configuration may also be used. However, for laser welding accompanied by wobbling, a resistance welding configuration is not assumed.

[0069] According to the manufacturing method of battery 1, the current interrupter 30 can be easily employed. If, for example, an ultrasonic bonding attempt were made to connect the positive electrode tab 11b and the positive electrode current collector plate 21 without using the positive electrode ribbon 23, as in a conventional embodiment corresponding to proportional bonding, a load would be placed on the current interrupter 30 due to the vibrations of the ultrasonic bonding. For this reason, in proportional bonding, the positive electrode current collector plate 21 had to be constructed in sections, the current interrupter 30 had to be laser-welded to one of the positive electrode current collector plates 21, and then the two positive electrode current collector plates 21 had to be laser-welded together. On the other hand, in the first embodiment, since the positive electrode tab 11b and the positive electrode current collector plate 21 are laser-welded, no load is placed on the current interrupter 30 due to the vibrations of the ultrasonic bonding when connecting the positive electrode tab 11b and the positive electrode current collector plate 21.

[0070] The positive electrode tab 11b and the positive electrode current collector plate 21 are laser-welded by a laser beam L1. Laser welding is applied in the manufacturing method of the battery 1. With this configuration, it is not necessary to directly crimp or press the welding area of ​​the positive electrode tab 11b and the positive electrode current collector plate 21 in order to sufficiently join them. That is, in the first embodiment, the joint portion of the positive electrode tab 11b and the positive electrode current collector plate 21 can be exposed and therefore laser-welded. Thus, in the first embodiment, the positive electrode tab 11b and the positive electrode current collector plate 21 can be welded by laser welding, which is highly versatile and allows for easy modification of welding conditions.

[0071] In the manufacturing method of battery 1, laser welding accompanied by wobbling is performed. This manufacturing method of battery 1 suppresses the occurrence of spatter and blowholes, and also suppresses welding defects between the positive electrode tab 11b and the positive electrode current collector plate 21, thereby improving the productivity and yield of battery 1. Furthermore, this manufacturing method of battery 1 allows for sufficient welding width between the positive electrode tab 11b and the positive electrode current collector plate 21, thereby improving the joint strength between the positive electrode tab 11b and the positive electrode current collector plate 21.

[0072] The positive electrode current collector plate 21, the positive electrode tab 11b, and the positive electrode ribbon 23 are laser-welded from the side of the positive electrode ribbon 23. This configuration expands the options for assembling the battery 1. Specifically, when laser welding from the side of the positive electrode ribbon 23, it is possible to crimp the positive electrode current collector plate 21 to the positive electrode terminal 41 after laser welding the positive electrode current collector plate 21 and the positive electrode tab 11b, or it is possible to crimp the positive electrode current collector plate 21 to the positive electrode terminal 41 before laser welding the positive electrode current collector plate 21 and the positive electrode tab 11b. On the other hand, in the case of laser welding from the positive electrode current collector plate 21 side, as in the conventional embodiment corresponding to proportionality, it is possible to crimp the positive electrode current collector plate 21 to the positive electrode terminal 41 after laser welding the positive electrode current collector plate 21 and the positive electrode tab 11b. However, if the positive electrode current collector plate 21 is crimped to the positive electrode terminal 41 before laser welding the positive electrode current collector plate 21 and the positive electrode tab 11b, the condition of the welding marks on the positive electrode current collector plate 21 becomes a problem. That is, in the proportionality case, if the welding marks on the positive electrode current collector plate 21 are relatively large, it becomes an obstacle when joining the positive electrode current collector plate 21 to, for example, the positive electrode side first insulating plate 62 or the cover 52.

[0073] The positive electrode tab 11b has a smaller heat capacity than the positive electrode current collector plate 21. With this configuration, the positive electrode tab 11b melts more easily than the positive electrode current collector plate 21. As shown in Figure 12, since the positive electrode tab 11b is sandwiched between the positive electrode ribbon 23 and the positive electrode current collector plate 21, it melts along its entire length in the stacking direction (Y-axis direction) and is joined to the positive electrode current collector plate 21. On the other hand, since the positive electrode current collector plate 21 is less likely to melt than the positive electrode tab 11b, it can be joined to the positive electrode tab 11b by melting only the region of its entire length in the stacking direction that is close to the positive electrode tab 11b. In other words, the welding conditions described above can be adopted. As a result, the quality of the positive electrode current collector plate 21 after laser welding can be maintained.

[0074] The positive electrode ribbon 23 has a smaller heat capacity than the positive electrode current collector plate 21. With this configuration, the positive electrode ribbon 23 melts more easily than the positive electrode current collector plate 21. As shown in Figure 12, the positive electrode ribbon 23 is melted along its entire length in the stacking direction (Y-axis direction) and joined to the positive electrode current collector plate 21. On the other hand, since the positive electrode current collector plate 21 is less likely to melt than the positive electrode ribbon 23, it can be melted only in the region close to the positive electrode tab 11b of its entire length in the stacking direction and joined to the positive electrode tab 11b. In other words, the welding conditions described above can be adopted. As a result, the quality of the positive electrode current collector plate 21 after laser welding can be maintained.

[0075] The positive electrode ribbon 23 has a thickness along the lamination direction that is greater than that of the positive electrode tab 11b. With this configuration, if the materials of the positive electrode ribbon 23 and the positive electrode tab 11b are the same or similar, the positive electrode ribbon 23 is less likely to melt than the positive electrode tab 11b. Therefore, during laser welding, the evaporation of the positive electrode ribbon 23 can be suppressed while the positive electrode tab 11b can be melted. In other words, the welding conditions described above can be adopted. Consequently, the positive electrode tab 11b and the positive electrode current collector plate 21 can be sufficiently laser welded.

[0076] The positive electrode ribbon 23 has a thinner thickness along the stacking direction than the positive electrode current collector plate 21. With this configuration, if the positive electrode ribbon 23 and the positive electrode current collector plate 21 are made of the same or similar material, the positive electrode ribbon 23 melts more easily than the positive electrode current collector plate 21. Therefore, as shown in Figure 12, when the positive electrode ribbon 23 melts along its entire length in the stacking direction (Y-axis direction) to transfer heat to the positive electrode tab 11b, and the positive electrode current collector plate 21 melts only in the region of its entire length in the stacking direction that is close to the positive electrode tab 11b, the positive electrode tab 11b and the positive electrode current collector plate 21 can be sufficiently laser welded.

[0077] The positive electrode current collector plate 21, the positive electrode tab 11b, and the positive electrode ribbon 23 are formed from the same or similar material. With this configuration, the specific heat of the positive electrode current collector plate 21, the positive electrode tab 11b, and the positive electrode ribbon 23 can be made the same or equivalent. Therefore, by considering the thickness of the positive electrode current collector plate 21, the positive electrode tab 11b, and the positive electrode ribbon 23 when setting the laser welding conditions, the positive electrode tab 11b covered by the positive electrode ribbon 23 and the positive electrode current collector plate 21 can be sufficiently laser welded.

[0078] The positive electrode current collector plate 21, the positive electrode tab 11b, and the positive electrode ribbon 23 are made of aluminum or an aluminum alloy. With this configuration, even when the frequency of the laser light L1 is in the infrared region and aluminum or an aluminum alloy, which has a relatively high reflectivity in the infrared region, is used as the material, the evaporation of the positive electrode tab 11b during laser welding can be prevented by the positive electrode ribbon 23. In other words, in order to laser weld the positive electrode tab 11b and the positive electrode current collector plate 21, sufficient heat input to the positive electrode tab 11b and the positive electrode current collector plate 21 is necessary, taking into account the energy loss due to the reflection of the laser light L1. Therefore, by having the positive electrode ribbon 23 function as a cover layer, the evaporation of the positive electrode tab 11b can be prevented. Thus, the positive electrode tab 11b and the positive electrode current collector plate 21 can be sufficiently laser welded.

[0079] As shown in Figure 8, the positive electrode tab 11b protrudes from the side edge 11c of the positive electrode current collector layer 11S. With this configuration, the positive electrode tab 11b and the positive electrode current collector plate 21 can be sufficiently joined while preventing interference between the positive electrode tab 11b and the positive electrode current collector layer 11S and the positive electrode active material layer 11T.

[0080] In the manufacturing method of battery 1, the first pressing member 501 and the second pressing member 502 are used to press the positive electrode ribbon 23, the positive electrode tab 11b, and the positive electrode current collector plate 21 against each other at both ends of the welded portion. With this manufacturing method of battery 1, the positive electrode tab 11b and the positive electrode current collector plate 21 can be brought into contact in a sufficiently tight manner without directly pressing the positive electrode ribbon 23, the positive electrode tab 11b, and the positive electrode current collector plate 21 together.

[0081] The charge / discharge element 10 is constructed by winding a positive electrode 11 and a negative electrode 12 with a separator 13 in between. As shown in the first embodiment, the battery 1 can be applied to a battery having a wound-type charge / discharge element 10.

[0082] The effects of the first embodiment have been described above using the configuration of joining the positive electrode tab 11b and the positive electrode current collector plate 21. In the first embodiment, the effects of joining the negative electrode tab 12b and the negative electrode current collector plate 22 are the same as the effects of joining the positive electrode tab 11b and the positive electrode current collector plate 21 described above.

[0083] [Second Embodiment] (Configuration of battery 2 in the second embodiment) The configuration of battery 2 will be explained with reference to Figures 19 and 20.

[0084] The battery 2 of the second embodiment is constructed by stacking multiple electrode tabs of the same polarity. The battery 2 of the second embodiment uses the same reference numerals as the battery 1 of the first embodiment, and its description is omitted. In the second embodiment, the description will focus on the components specific to the battery 2. In the description of the manufacturing method of the battery 2 of the second embodiment, only the manufacturing process specific to the battery 2 will be described, and the description of the manufacturing process similar to that of a general battery will be omitted.

[0085] The battery 2 of the second embodiment differs from the battery 1 of the first embodiment in that it has a charge / discharge element 210 instead of a charge / discharge element 10. As shown in Figure 19, the charge / discharge element 210 has one side portion 210a from which a positive electrode tab 211b and a negative electrode tab 212b protrude, another side portion 210b facing the one side portion 210a, and an outer peripheral portion 210c located between the one side portion 210a and the other side portion 210b. The charge / discharge element 210 is constructed of a wound type in which a positive electrode 211 and a negative electrode 212 are stacked and wound together via a separator 13. The positive electrode 211 has a plurality of positive electrode tabs 211b formed thereon. The negative electrode 212 has a plurality of negative electrode tabs 212b formed thereon.

[0086] Multiple negative electrode tabs 212b are stacked on top of each other, as shown in Figure 20. The multiple negative electrode tabs 212b are laser-welded to the negative electrode current collector plate 22 while covered by the negative electrode ribbon 24. That is, the multiple negative electrode tabs 212b are laser-welded to the negative electrode ribbon 24 and the negative electrode current collector plate 22 while sandwiched between them. Although multiple negative electrode tabs 212b are stacked on top of each other, the heat capacity of one negative electrode tab 212b is configured to be smaller than the heat capacity of the negative electrode ribbon 24.

[0087] The laser welding configuration on the positive electrode 211 side is the same as that on the negative electrode 212 side. That is, multiple positive electrode tabs 211b are laser-welded to the positive electrode ribbon 23 and the positive electrode current collector plate 21 while sandwiched between them. Multiple positive electrode tabs 211b are stacked on top of each other, but the heat capacity of one positive electrode tab 211b is configured to be smaller than the heat capacity of the positive electrode ribbon 23.

[0088] (Method for manufacturing battery 2 of the second embodiment) The manufacturing method for battery 2 will be explained.

[0089] A manufacturing method specific to the battery 2 of the second embodiment involves laser welding a plurality of positive electrode tabs 211b, which are covered and overlapped by a positive electrode ribbon 23, to a positive electrode current collector plate 21. In the second embodiment, a plurality of negative electrode tabs 212b, which are covered and overlapped by a negative electrode ribbon 24, to a negative electrode current collector plate 22.

[0090] (Effects of the battery 2 and the manufacturing method of the battery 2 according to the second embodiment) The effects of the battery 2 and the manufacturing method of the battery 2 according to the second embodiment will be described.

[0091] The battery 2 of the second embodiment is of the wound type and is composed of a charge / discharge body 210 in which multiple electrode tabs of the same polarity are superimposed. With this configuration, the evaporation of the positive electrode tab 211b during laser welding is prevented by the positive electrode ribbon 23, so that the multiple positive electrode tabs 211b and the positive electrode current collector plate 21 are sufficiently joined. Similarly, in such a battery 2, the evaporation of the negative electrode tab 212b during laser welding is prevented by the negative electrode ribbon 24, so that the multiple negative electrode tabs 212b and the negative electrode current collector plate 22 are sufficiently joined. Furthermore, in the manufacturing method of such a battery 2, since the evaporation of the positive electrode tab 211b during laser welding can be prevented by the positive electrode ribbon 23, welding defects between the multiple positive electrode tabs 211b and the positive electrode current collector plate 21 can be suppressed, thereby improving the productivity and yield of the battery 2. Similarly, in this method of manufacturing the battery 2, evaporation of the negative electrode tab 212b during laser welding can be prevented by the negative electrode ribbon 24, thereby suppressing welding defects between the negative electrode tab 212b and the negative electrode current collector plate 22, and improving the productivity and yield of the battery 2.

[0092] The heat capacity of the positive electrode ribbon 23 is greater than the heat capacity of one positive electrode tab 211b. Therefore, for example, when laser welding is performed from the side of the positive electrode ribbon 23, evaporation of all positive electrode tabs 211b, including one positive electrode tab 211b that is in direct contact with the positive electrode ribbon 23, can be prevented. Similarly, the heat capacity of the negative electrode ribbon 24 is greater than the heat capacity of one negative electrode tab 212b. Therefore, for example, when laser welding is performed from the side of the negative electrode ribbon 24, evaporation of all negative electrode tabs 212b, including one negative electrode tab 212b that is in direct contact with the negative electrode ribbon 24, can be prevented.

[0093] In the second embodiment, multiple electrode tabs of the same polarity are stacked on top of each other. Therefore, when laser welding is performed, energy loss occurs at the interface of adjacent positive electrode tabs 211b, for example. For this reason, it is necessary to increase the heat input during laser welding to account for the energy loss at the interface of adjacent positive electrode tabs 211b. In the second embodiment, since evaporation of the multiple positive electrode tabs 211b during laser welding is prevented by the positive electrode ribbon 23, even if energy loss occurs at the interface of adjacent positive electrode tabs 211b during laser welding, the multiple positive electrode tabs 211b and the positive electrode current collector plate 21 can be sufficiently joined.

[0094] Although the second embodiment was described based on a laser welding configuration, a resistance welding configuration may also be used. When the second embodiment is configured for resistance welding, it will have the same effects as the laser welding configuration.

[0095] [Third Embodiment] (Configuration of battery 3 in the third embodiment) The configuration of battery 3 will be explained with reference to Figures 21 and 22.

[0096] The battery 3 of the third embodiment is composed of a laminated type in which the charge / discharge element 310 is not wound. The battery 3 of the third embodiment uses the same reference numerals as the battery 1 of the first embodiment, and its description is omitted. In the third embodiment, the description will focus on the components specific to the battery 3. In the description of the manufacturing method of the battery 3 of the third embodiment, only the manufacturing process specific to the battery 3 will be described, and the description of the manufacturing process similar to that of a general battery will be omitted.

[0097] The battery 3 of the third embodiment differs from the battery 1 of the first embodiment in that it has a charge / discharge body 310 instead of a charge / discharge body 10. The charge / discharge body 310 has one side portion 310a from which a positive electrode tab 311b and a negative electrode tab 312b protrude, another side portion 310b opposite to the one side portion 310a, and an outer peripheral portion 310c located between the one side portion 310a and the other side portion 310b. The charge / discharge body 310 is a stacked type in which a positive electrode 311 and a negative electrode 312 are stacked via a separator 313. The charge / discharge body 310 is composed of multiple stacks of rectangular positive electrodes 311, separators 313, and negative electrodes 312 in the order of positive electrode 311, separator 313, negative electrode 312, separator 313. Each positive electrode 311 has one positive electrode tab 311b formed on it. Each negative electrode 312 has one negative electrode tab 312b formed on it.

[0098] Multiple negative electrode tabs 312b are stacked on top of each other, as shown in Figure 22. The multiple negative electrode tabs 312b are laser-welded to the negative electrode current collector plate 22 while covered by the negative electrode ribbon 24. That is, the multiple negative electrode tabs 312b are laser-welded to the negative electrode ribbon 24 and the negative electrode current collector plate 22 while sandwiched between them.

[0099] The laser welding configuration on the positive electrode 311 side is the same as the laser welding configuration on the negative electrode 312 side. That is, multiple positive electrode tabs 311b are laser-welded to the positive electrode ribbon 23 and the positive electrode current collector plate 21 while sandwiched between them.

[0100] As a modified example of the charge / discharge body 310, a laminated type can be applied in which a single elongated separator is alternately arranged with a plurality of relatively short positive electrodes and a plurality of negative electrodes facing each other via the separator. This modified example is a so-called Z-fold laminated type. In a charge / discharge body with such a configuration, the positive and negative electrodes face each other via the separator by folding and laminating the separator.

[0101] (Method for manufacturing battery 3 of the third embodiment) The manufacturing method for battery 3 will be explained.

[0102] The manufacturing method specific to battery 3 of the third embodiment is the same as the manufacturing method specific to battery 2 of the second embodiment.

[0103] (Effects of the battery 3 and the manufacturing method of the battery 3 according to the third embodiment) The effects of the battery 3 and the manufacturing method of the battery 3 according to the third embodiment will be described.

[0104] The battery 3 of the third embodiment is composed of a laminated type in which the charge / discharge element 310 is not wound. The charge / discharge element 310 is composed of multiple stacks of rectangular positive electrodes 311, separators 313, and negative electrodes 312 in the order of separator 313, negative electrode 312, separator 313. In other words, the battery 3 of the third embodiment is composed of multiple electrode tabs of the same polarity stacked together, similar to the battery 2 of the second embodiment. Such a battery 3 of the third embodiment can obtain the same effects as the battery 2 of the second embodiment.

[0105] Although the third embodiment was described based on a laser welding configuration, a resistance welding configuration may also be used. When the third embodiment is configured for resistance welding, it will have the same effects as the laser welding configuration.

[0106] [Fourth Embodiment] (Configuration of battery 4 in the fourth embodiment) The configuration of battery 4 will be explained with reference to Figures 23 and 24.

[0107] The battery 4 of the fourth embodiment is composed of two charge / discharge elements 410 arranged side by side. The battery 4 of the fourth embodiment uses the same reference numerals as the battery 1 of the first embodiment, and its description is omitted. In the fourth embodiment, the description will focus on the components specific to the battery 4. In the description of the manufacturing method of the battery 4 of the fourth embodiment, only the manufacturing process specific to the battery 4 will be described, and the description of the manufacturing process similar to that of a general battery will be omitted.

[0108] The battery 4 of the fourth embodiment differs from the battery 1 of the first embodiment in that it has two charge / discharge elements 410 instead of a charge / discharge element 10. Each charge / discharge element 410 has one side portion 410a from which a positive electrode tab 411b and a negative electrode tab 412b protrude, another side portion 410b opposite to the one side portion 410a, and an outer peripheral portion 410c located between the one side portion 410a and the other side portion 410b. The two charge / discharge elements 410 are arranged in the short direction (Y-axis direction) of the battery 4. The two charge / discharge elements 410 are electrically connected in parallel, for example. The charge / discharge element 410 is of a wound type in which a positive electrode 411 and a negative electrode 412 are stacked and wound together via a separator 413. The positive electrode 411 has a plurality of positive electrode tabs 411b formed thereon. The negative electrode 412 has a plurality of negative electrode tabs 412b formed thereon. The positive electrode current collector plate 121 and negative electrode current collector plate 122 of the current collector 120, the positive electrode terminal 141 and negative electrode terminal 142 of the external terminal 140, the container and lid 152 of the outer casing 150, the negative electrode side first insulating plate 163 of the insulator 160, etc., and the sealing body are configured to be longer in the shorter direction (Y-axis direction) compared to the battery 1. By using this configuration, each component of the battery 4 is made to match the size of the two charge / discharge units 410 that are arranged side by side along the shorter direction (Y-axis direction) of the battery 4.

[0109] The negative electrode current collector plate 122 is laser-welded to the negative electrode current collector plate 122, with each of the two charge / discharge bodies 410 having multiple negative electrode tabs 412b, each of which is covered by a negative electrode ribbon 24. The multiple negative electrode tabs 412b on one charge / discharge body 410 and the multiple negative electrode tabs 412b on the other charge / discharge body 410 face each other along the short direction (Y-axis direction) of the negative electrode current collector plate 122.

[0110] The laser welding configuration on the positive electrode 411 side is the same as the laser welding configuration on the negative electrode 412 side.

[0111] (Method for manufacturing the battery 4 of the fourth embodiment) The manufacturing method for battery 4 will be explained.

[0112] A manufacturing method specific to the battery 4 of the fourth embodiment involves arranging multiple sets (for example, two sets) of positive electrode tabs 411b, covered and overlapped by positive electrode ribbons 23, facing each other along the short direction (Y-axis direction) of the battery 4, on the positive electrode current collector plate, and then laser welding them together. In addition, in the fourth embodiment, multiple sets (for example, two sets) of negative electrode tabs 412b, covered and overlapped by negative electrode ribbons 24, on the negative electrode current collector plate 122, facing each other along the short direction (Y-axis direction) of the battery 4, and then laser welding them together.

[0113] (Effects of the battery 4 and the manufacturing method of the battery 4 according to the fourth embodiment) The effects of the battery 4 and the method for manufacturing the battery 4 according to the fourth embodiment will be described.

[0114] The battery 4 of the fourth embodiment is of the wound type and is configured by providing multiple sets (for example, two sets) of charge / discharge bodies 410 in which multiple electrode tabs of the same polarity are stacked. This battery 4 of the fourth embodiment can obtain the same effects as the battery 2 of the second embodiment and the battery 3 of the third embodiment.

[0115] Although the fourth embodiment was described based on a laser welding configuration, a resistance welding configuration may also be used. When the fourth embodiment is configured for resistance welding, it will have the same effects as the laser welding configuration.

[0116] [Fifth Embodiment] (Configuration of battery 5 in the fifth embodiment) The configuration of battery 5 will be explained with reference to Figures 25 to 27.

[0117] In the fifth embodiment, the battery 5 has a convex positive electrode junction 221f formed on the positive electrode current collector plate 221. Also, a convex negative electrode junction 222f is formed on the negative electrode current collector plate 222. In the fifth embodiment, the same reference numerals are used for the same components as in the first embodiment (battery 1), and their descriptions are omitted. The fifth embodiment will focus on the components specific to battery 5. In describing the manufacturing method of the fifth embodiment, only the manufacturing process specific to battery 5 will be described, and the manufacturing process similar to that of a general battery will be omitted.

[0118] The positive electrode current collector plate 221 includes, for example, a first base portion 221a having the same shape as the first base portion 21a in Figure 15, a second base portion 221b having the same shape as the second base portion 21b, and a connecting portion 221c having the same shape as the connecting portion 21c, as shown in Figures 26 and 27. Furthermore, a recess having the same shape as the recess 21d shown in Figure 15 is formed on the upper surface of the second base portion 221b. A weak portion having the same shape as the weak portion 21e shown in Figure 15 is formed in the center of the recess of the second base portion 221b.

[0119] As shown in Figure 27, a convex positive electrode joint 221f is formed on the first base portion 221a of the positive electrode current collector plate 221, projecting downward (negative Z-axis direction). The positive electrode joint 221f is triangular in shape. The positive electrode joint 221f faces the charge / discharge body 10 and extends in the longitudinal direction (X-axis direction) of the charge / discharge body 10. The positive electrode joint 221f has higher rigidity than the positive electrode tab 11b in the stacking direction (Z-axis direction) of the positive electrode tab 11b and the positive electrode current collector plate 221. The tip of the positive electrode joint 221f and the positive electrode tab 11b are laser-welded. When the positive electrode tab 11b is laser-welded to the positive electrode joint 221f, it is pressed toward the positive electrode joint 221f, causing it to deform to conform to the convex positive electrode joint 221f. The positive electrode current collector plate 221 is formed of, for example, aluminum or an aluminum alloy.

[0120] Here, as shown in Figure 27, the welded portion 23g of the positive electrode ribbon 23, the welded portion 11g of the positive electrode tab 11b, and the welded portion 221g of the positive electrode joint 221f are laser-welded. In the state where the positive electrode ribbon 23 is laser-welded to the positive electrode tab 11b and the positive electrode joint 221f, the portion of the positive electrode ribbon 23 other than the welded portion 23g is curved and sagging in the negative Z-axis direction due to its own weight. Similarly, the portion of the positive electrode tab 11b other than the welded portion 11g is curved and sagging in the negative Z-axis direction due to its own weight.

[0121] The negative electrode current collector plate 222 includes, for example, a base 222a having the same shape as the base 22a in Figure 13, and an insertion hole 222b having the same shape as the insertion hole 22b, as shown in Figure 25.

[0122] As shown in Figure 25, a convex negative electrode joint portion 222f is formed on the base portion 222a of the negative electrode current collector plate 222, projecting downward (in the negative Z-axis direction). The negative electrode joint portion 222f is triangular in shape. The negative electrode joint portion 222f faces the charge / discharge body 10 and extends in the longitudinal direction (X-axis direction) of the charge / discharge body 10. The negative electrode joint portion 222f has higher rigidity than the negative electrode tab 12b in the stacking direction (Z-axis direction) of the negative electrode tab 12b and the negative electrode current collector plate 222. The tip of the negative electrode joint portion 222f and the negative electrode tab 12b are laser welded. When the negative electrode tab 12b is laser welded to the negative electrode joint portion 222f, it is pressed toward the negative electrode joint portion 222f, causing it to deform to conform to the convex negative electrode joint portion 222f. The negative electrode current collector plate 222 is made of, for example, copper or a copper alloy.

[0123] (Method for manufacturing the battery 5 of the fifth embodiment) The manufacturing method of battery 5 will be explained with reference to Figures 28 to 30.

[0124] In the description of the manufacturing method of the battery 5 of the fifth embodiment, only the manufacturing process specific to the battery 5 will be described, and the description of the manufacturing process similar to that of a general battery will be omitted. Specifically, the manufacturing method of the battery 5 will be described in which the negative electrode tab 12b covered with the negative electrode ribbon 24 is laser-welded to the convex negative electrode joint portion 222f of the negative electrode current collector plate 222. The structure of the laser welding on the positive electrode 11 side is the same as the structure of the laser welding on the negative electrode 12 side, so the description will be omitted.

[0125] As shown in Figures 28 to 29, in the fifth embodiment, the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 222 are stacked. In the fifth embodiment, the first pressing member 501 and the second pressing member 502 are used to bring the sides of the welded portions of the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 222 into contact. The first pressing member 501 and the second pressing member 502 bring the negative electrode ribbon 24 and the negative electrode tab 12b into close contact, and also bring the negative electrode joint portion 222f of the negative electrode tab 12b and the negative electrode current collector plate 222 into close contact. The negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode joint portion 222f of the negative electrode current collector plate 222 are stacked in close contact with each other in the Y-axis space between the first pressing member 501 and the second pressing member 502, with the welded portion of the negative electrode ribbon 24 exposed.

[0126] As shown in Figure 29, when the first pressing member 501 and the second pressing member 502 press the negative electrode ribbon 24, the negative electrode tab 12b, and the welded portion of the negative electrode current collector plate 222 against each other, the negative electrode ribbon 24 and the negative electrode tab 12b are pulled toward the ends of the negative electrode joint 222f. That is, when the negative electrode ribbon 24 and the negative electrode tab 12b are pressed along both ends of the negative electrode joint 222f (both ends in the Y-axis direction) while in contact with the negative electrode joint 222f, tension is applied to the negative electrode ribbon 24 and the negative electrode tab 12b in both positive and negative directions along the Y-axis centered on the negative electrode joint 222f. As a result, the negative electrode ribbon 24 and the negative electrode tab 12b are pressed against the negative electrode joint 222f. The portions of the negative electrode ribbon 24 and negative electrode tab 12b that are pressed against the negative electrode joint 222f deform into a convex shape to conform to the shape of the negative electrode joint 222f. The negative electrode ribbon 24, negative electrode tab 12b, and negative electrode joint 222f are in close contact.

[0127] As shown in Figure 30, in the fifth embodiment, the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 222 are laser-welded. In the fifth embodiment, laser light L1 is irradiated from between the first pressing member 501 and the second pressing member 502 toward the negative electrode ribbon 24 to laser-weld the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 222. The welded portion of the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 222 extends along the longitudinal direction (X-axis direction) of the battery 5. Therefore, in the fifth embodiment, the laser light L1 is scanned in the X-axis direction to continuously laser-weld the negative electrode ribbon 24, the negative electrode tab 12b, and the negative electrode current collector plate 222. In addition, in the fifth embodiment, laser welding accompanied by wobbling is performed. In addition, in the fifth embodiment, the laser light L1 may be scanned in the X-axis direction to intermittently laser-weld the welded portion of the negative electrode tab 12b and the negative electrode current collector plate 222. Subsequently, in the fifth embodiment, the first pressing member 501 and the second pressing member 502 are retracted from the negative electrode tab 12b.

[0128] (Effects of the battery 5 and the manufacturing method of the fifth embodiment) The effects of the battery 5 and the manufacturing method of the fifth embodiment will be described below. The following mainly describes the effects related to the joining of the positive electrode tab 11b and the positive electrode current collector plate 221. The effects related to the joining of the positive electrode tab 11b and the positive electrode current collector plate 221 are the same as those related to the joining of the negative electrode tab 12b and the negative electrode current collector plate 222.

[0129] In the fifth embodiment of the battery 5, the convex positive electrode joint 221f of the positive electrode current collector plate 221, the positive electrode tab 11b, and, for example, the positive electrode ribbon 23 are laminated and laser-welded. In the manufacturing method of the battery 5 of the fifth embodiment, the convex positive electrode joint 221f of the positive electrode current collector plate 221, the positive electrode tab 11b, and, for example, the positive electrode ribbon 23 are laser-welded. With this configuration, the positive electrode tab 11b and the positive electrode joint 221f of the positive electrode current collector plate 221 can be sufficiently welded to each other while in sufficient contact. That is, for example, when the positive electrode joint 221f, which is the welding area, protrudes from the positive electrode current collector plate 221 as in the fifth embodiment, it is easy to bring the positive electrode tab 11b and the positive electrode joint 221f into close contact. For this reason, for example, the positive electrode tab 11b and the positive electrode joint 221f can be sufficiently welded to make them electrically conductive. Therefore, the battery 5 can, for example, improve the conductivity between the positive electrode tab 11b and the positive electrode current collector plate 221. Furthermore, in the manufacturing method of the battery 5, for example, welding defects between the positive electrode tab 11b and the positive electrode current collector plate 221 can be suppressed, thereby improving the productivity and yield of the battery 5.

[0130] The positive electrode contact portion 221f of the positive electrode current collector plate 221 is formed in a triangular shape. With this configuration, stress can be concentrated on the triangular corner portion (tip portion) of the positive electrode tab 11b and the positive electrode contact portion 221f, allowing them to come into close contact with each other. As a result, the positive electrode contact portion 221f of the positive electrode current collector plate 221 and the positive electrode tab 11b can be sufficiently joined.

[0131] The positive electrode tab 11b, which is deformed into a convex shape along the positive electrode joint 221f of the positive electrode current collector plate 221, is welded to the positive electrode joint 221f. With this configuration, by bringing the positive electrode tab 11b and the positive electrode joint 221f into close contact along the convex positive electrode joint 221f, a sufficient area for welding can be secured between the positive electrode tab 11b and the positive electrode joint 221f. In other words, the positive electrode tab 11b can be welded in close contact with the positive electrode joint 221f at any of its convexly deformed portions.

[0132] The positive electrode tab 11b and the tip of the positive electrode joint 221f of the positive electrode current collector plate 221 are welded together. With this configuration, the battery 5 can sufficiently join the positive electrode tab 11b and the positive electrode current collector plate 221 with a minimum welding area. Alternatively, the positive electrode tab 11b may be welded to one of the two opposing inclined surfaces of the positive electrode joint 221f. Furthermore, the positive electrode tab 11b may be welded to the entire surface of the positive electrode joint 221f, from the base end to the tip in the negative Z-axis direction.

[0133] The positive electrode joint portion 221f of the positive electrode current collector plate 221 has higher rigidity in the stacking direction (Z-axis direction) of the positive electrode tab 11b and the positive electrode current collector plate 221 than the positive electrode tab 11b. With this configuration, the positive electrode tab 11b can be deformed to conform to the shape of the positive electrode joint portion 221f, and the positive electrode tab 11b can be welded in close contact with the positive electrode joint portion 221f. Therefore, the positive electrode tab 11b and the positive electrode current collector plate 221 can be sufficiently joined.

[0134] The positive electrode junction 221f of the positive electrode current collector plate 221 faces the charge / discharge body 10 and extends in the longitudinal direction (X-axis direction) of the rectangular charge / discharge body 10. With this configuration, the welding area between the positive electrode tab 11b and the positive electrode current collector plate 221 can be sufficiently secured along the longitudinal direction (X-axis direction) of the charge / discharge body 10.

[0135] In the manufacturing method of the battery 5, the first pressing member 501 and the second pressing member 502 are used to press the positive electrode ribbon 23, the positive electrode tab 11b, and the positive electrode current collector plate 221 against each other at both ends of the welded portion. With this manufacturing method of the battery 5, the positive electrode ribbon 23, the positive electrode tab 11b, and the positive electrode current collector plate 221 can be brought into contact with the positive electrode tab 11b in a sufficiently tight fit without directly pressing them together. When the positive electrode tab 11b is in contact with the positive electrode joint 221f and pressed along both ends of the positive electrode joint 221f (both ends in the Y-axis direction), tension is applied to the positive electrode tab 11b in both positive and negative directions along the Y-axis centered on the positive electrode joint 221f. As a result, the positive electrode tab 11b and the positive electrode joint 221f of the positive electrode current collector plate 221 come into contact in a tight fit. Therefore, the positive electrode tab 11b and the positive electrode current collector plate 221 can be sufficiently welded together.

[0136] The effects of the fifth embodiment have been described above using the configuration of joining the positive electrode tab 11b and the positive electrode current collector plate 221. In the fifth embodiment, the effects of joining the negative electrode tab 12b and the negative electrode current collector plate 222 are the same as the effects of joining the positive electrode tab 11b and the positive electrode current collector plate 221 described above.

[0137] Although the fifth embodiment was described based on a laser welding configuration, a resistance welding configuration may also be used. When the fifth embodiment is configured for resistance welding, it will have the same effects as the laser welding configuration.

[0138] [Modified version of the fifth embodiment] (Configuration and effects of modified examples 1 to 3 of the battery 5 of the fifth embodiment) With respect to the battery 5 of the fifth embodiment, the joints of the positive electrode current collector plate 221 in the positive electrode joint 221f of the positive electrode current collector plate 221 in the modified examples 1 to 3 will be described with reference to Figures 31 to 33. The modified examples of the negative electrode joint 222f of the negative electrode current collector plate 222 are the same as the modified examples of the positive electrode joint 221f of the positive electrode current collector plate 221, so their description will be omitted.

[0139] As shown in Figure 31, the positive electrode joint portion 223f of the positive electrode current collector plate 223 is formed in a trapezoidal shape that protrudes in the negative Z-axis direction, with the portion in contact with the first base portion 223a as the base. The positive electrode joint portion 223f has a trapezoidal shape in which the cross-section in the Y-axis direction and the Z-axis direction tapers toward the negative Z-axis direction, and extends in the X-axis direction. The tip of the positive electrode joint portion 223f is formed on a plane parallel to the first base portion 223a, and both ends in the Y-axis direction are formed on inclined surfaces that slope toward the first base portion 223a. With this configuration, the planar portion at the tip of the positive electrode joint portion 223f can sufficiently secure a welding area with the positive electrode tab 11b, so that the positive electrode joint portion 223f and the positive electrode tab 11b covered by the positive electrode ribbon 23 can be sufficiently joined.

[0140] As shown in Figure 32, the positive electrode joint portion 224f of the positive electrode current collector plate 224 is formed in an arc shape that protrudes in the negative Z-axis direction, starting from the portion in contact with the first base portion 224a. The positive electrode joint portion 224f has an arc shape in cross-section in the Y-axis and Z-axis directions and extends in the X-axis direction. The positive electrode joint portion 224f is formed in a semicircular shape toward the tip that protrudes from the first base portion 224a in the negative Z-axis direction. The positive electrode joint portion 224f may also be semi-elliptical or semi-circular. With such a configuration, the arc-shaped positive electrode joint portion 224f eliminates the inflection point at the contact portion with the positive electrode tab 11b, thereby suppressing the load on the positive electrode tab 11b while sufficiently joining the positive electrode joint portion 224f and the positive electrode tab 11b covered by the positive electrode ribbon 23.

[0141] As shown in Figure 33, the positive electrode joint portion 225f of the positive electrode current collector plate 225 is formed in an arc shape that protrudes in the negative Z-axis direction, starting from the portion in contact with the first base portion 225a, and its tip is formed in a plane parallel to the first base portion 225a. The cross-section of the positive electrode joint portion 225f in the Y-axis and Z-axis directions is an arc shape with a plane at its tip, and extends in the X-axis direction. With this configuration, the plane portion at the tip of the positive electrode joint portion 225f can sufficiently secure a welding area with the positive electrode tab 11b, so that the positive electrode joint portion 225f and the positive electrode tab 11b can be sufficiently joined. Furthermore, with this configuration, the arc portion around the tip of the positive electrode joint portion 225f can reduce the load on the positive electrode tab 11b covered by the positive electrode ribbon 23.

[0142] [Sixth Embodiment] (Configuration of battery 6 in the sixth embodiment) The configuration of battery 6 will be explained with reference to Figure 34.

[0143] The battery 6 of the sixth embodiment corresponds to a configuration that combines the second embodiment shown in Figures 19 and 20 with, for example, the fifth embodiment shown in Figure 25. Furthermore, the battery 6 corresponds to a configuration that combines the third embodiment shown in Figures 21 and 22 with, for example, the fifth embodiment shown in Figure 25.

[0144] In battery 6, multiple positive electrode tabs 211b, or multiple positive electrode tabs 311b, covered by a positive electrode ribbon 23, are laser-welded to the positive electrode junction 221f of the positive electrode current collector plate 221. Also, as shown in Figure 34, in battery 6, multiple negative electrode tabs 212b, or multiple negative electrode tabs 312b, covered by a negative electrode ribbon 24, are laser-welded to the negative electrode junction 222f of the negative electrode current collector plate 222.

[0145] (Method for manufacturing the battery 6 of the sixth embodiment) Let's explain the configuration of battery 6.

[0146] The manufacturing method for the battery 6 of the sixth embodiment is the same as the manufacturing method for the battery 5 of the fifth embodiment. However, in the sixth embodiment, as shown in Figure 34, a plurality of negative electrode tabs 212b or negative electrode tabs 312b, which are covered and overlapped by the negative electrode ribbon 24, are laser-welded to the negative electrode current collector plate 222. Similarly, in the sixth embodiment, a plurality of positive electrode tabs 211b or positive electrode tabs 311b, which are covered and overlapped by the positive electrode ribbon 23, are laser-welded to the positive electrode current collector plate 221.

[0147] (Effects of the battery 6 and the method for manufacturing the battery 6 according to the sixth embodiment) The effects of the battery 6 and the manufacturing method of the battery 6 according to the sixth embodiment will be described below. The following mainly describes the effects relating to the joining of, for example, the negative electrode tab 212b and the negative electrode current collector plate 222. For example, the effects relating to the joining of the negative electrode tab 212b and the negative electrode current collector plate 222 are similar to those relating to the joining of, for example, the positive electrode tab 211b and the positive electrode current collector plate 221.

[0148] Multiple overlapping negative electrode tabs 212b and the negative electrode joint portion 222f of the negative electrode current collector plate 222 are welded together. Even with this configuration, all of the multiple negative electrode tabs 212b and the negative electrode joint portion 222f can be welded directly or indirectly without creating gaps between adjacent negative electrode tabs 212b. That is, because the negative electrode joint portion 222f, which is the welding area, protrudes from the negative electrode current collector plate 222, it is easy to bring all of the multiple negative electrode tabs 212b and the negative electrode joint portion 222f into close contact, either directly or indirectly. For this reason, all of the multiple negative electrode tabs 212b and the positive electrode joint portion 221f can be sufficiently joined.

[0149] The negative electrode joint 222f of the negative electrode current collector plate 222 has higher rigidity in the stacking direction (Z-axis direction) of the negative electrode tabs 212b and the negative electrode current collector plate 222 than, for example, multiple overlapping negative electrode tabs 212b. With this configuration, even if multiple negative electrode tabs 212b are overlapped, all of the multiple negative electrode tabs 212b can be deformed to conform to the shape of the negative electrode joint 222f of the negative electrode current collector plate 222, and welded in close contact with the negative electrode joint 222f, either directly or indirectly. As a result, all negative electrode tabs 212b and the negative electrode current collector plate 222 can be sufficiently joined.

[0150] The effects of the sixth embodiment have been described above using the configuration of welding a plurality of overlapping negative electrode tabs 212b etc. to a negative electrode current collector plate 222. In the sixth embodiment, the effects of welding a plurality of overlapping positive electrode tabs to a positive electrode current collector plate 221 are the same as the effects of welding a plurality of overlapping negative electrode tabs 212b to a negative electrode current collector plate 222 described above.

[0151] Although the sixth embodiment was described based on a laser welding configuration, a resistance welding configuration may also be used. When the sixth embodiment is configured for resistance welding, it will have the same effects as the laser welding configuration.

[0152] [Seventh Embodiment] (Configuration and manufacturing method of battery 7 in the seventh embodiment) The configuration of battery 7 will be explained with reference to Figure 35.

[0153] The battery 7 of the seventh embodiment corresponds to a configuration that combines the fourth embodiment shown in Figures 23 and 24 with, for example, the fifth embodiment shown in Figure 25.

[0154] The negative electrode current collector plate 322 has, for example, two negative electrode joints 322f formed spaced apart in the short direction (Y-axis direction) of the battery 7. Each negative electrode joint 322f is formed in a triangular shape. Each negative electrode joint 322f faces the charge / discharge body 410 and extends in the long direction (X-axis direction) of the charge / discharge body 410. Multiple negative electrode tabs 412b provided on each of the two charge / discharge bodies 410 are superimposed on one of the two negative electrode joints 322f formed on the negative electrode current collector plate 322 that are relatively close to each other and laser-welded. Multiple negative electrode tabs 412b covered by the negative electrode ribbon 24 are laser-welded to each negative electrode joint 322f of the negative electrode current collector plate 322.

[0155] The configuration of the connection between the positive electrode current collector plate and the multiple positive electrode tabs 411b is the same as the configuration of the negative electrode current collector plate 322 and the multiple negative electrode tabs 412b.

[0156] As a modification of the seventh embodiment, three or more charge / discharge elements may be arranged in a row in the short direction (Y-axis direction) of the battery 7. In this case, three or more joints are formed on the current collector plate, spaced apart in the short direction (Y-axis direction) of the battery.

[0157] (Method for manufacturing the battery 7 of the seventh embodiment) Let's explain the configuration of battery 7.

[0158] The manufacturing method for the battery 7 of the seventh embodiment is the same as the manufacturing method for the battery 6 of the sixth embodiment. However, in the seventh embodiment, as shown in Figure 35, multiple sets (for example, two sets) of negative electrode tabs 412b, covered and overlapped by negative electrode ribbons 24, are arranged facing each other along the short direction (Y-axis direction) of the battery 7 on the negative electrode current collector plate 322 and laser-welded. Similarly, in the seventh embodiment, multiple sets (for example, two sets) of positive electrode tabs 411b, covered and overlapped by positive electrode ribbons 23, are arranged facing each other along the short direction (Y-axis direction) of the battery 7 on the positive electrode current collector plate and laser-welded.

[0159] (Effects of the battery 7 and the manufacturing method of the battery 7 according to the seventh embodiment) The effects of the battery 7 and the manufacturing method of the battery 7 according to the seventh embodiment will be described.

[0160] In the seventh embodiment, the battery 7 has multiple (two) wound-type charge / discharge elements 410 arranged side by side in the short direction (Y-axis direction) of the battery 7. Here, for example, the negative electrode current collector plate 322 has two negative electrode junctions 322f formed spaced apart in the short direction (Y-axis direction) of the battery 7. Therefore, the multiple negative electrode tabs 412b provided on each of the two charge / discharge elements 410 can be bundled and joined to either of the two negative electrode junctions 322f formed on the negative electrode current collector plate 322 that are relatively close to each other. The positive electrode current collector plate also provides the same effect as the negative electrode current collector plate 322 described above.

[0161] As a modification of the seventh embodiment, three or more charge / discharge elements may be arranged in a row in the short direction (Y-axis direction) of the battery 7. In this case, three or more joints are formed on the current collector plate, spaced apart in the short direction (Y-axis direction) of the battery.

[0162] Although the seventh embodiment was described based on a laser welding configuration, a resistance welding configuration may also be used. When the seventh embodiment is configured for resistance welding, it will have the same effects as the laser welding configuration.

[0163] The battery of the present invention is not limited to the configuration described in the embodiments, but can be appropriately configured based on the content described in the claims.

[0164] The battery of the present invention is not limited to a configuration in which the first current collector, electrode tabs, and second current collector are laser-welded. The battery of the present invention can be applied to a configuration in which the first current collector, electrode tabs, and second current collector are resistance-welded. The battery of the present invention is not limited to lithium-ion batteries. The battery of the present invention can be applied to, for example, nickel-metal hydride batteries and lead-acid batteries. The battery of the present invention is not limited to secondary batteries. The battery of the present invention can be applied to primary batteries.

[0165] For example, in the first embodiment, the positive electrode current collector plate 21 and the positive electrode terminal 41 are configured as separate components, but the positive electrode current collector plate 21 and the positive electrode terminal 41 may be configured as an integrated unit. That is, the first current collector may be configured to include the positive electrode current collector plate 21 and the positive electrode terminal 41. Similarly, for example, in the first embodiment, the negative electrode current collector plate 22 and the negative electrode terminal 42 are configured as separate components, but the negative electrode current collector plate 22 and the negative electrode terminal 42 may be configured as an integrated unit. That is, the first current collector may be configured to include the negative electrode current collector plate 22 and the negative electrode terminal 42.

[0166] Each embodiment is described in detail or in a simplified manner to illustrate the present invention, and it is not necessary to have all the configurations described, or to have configurations that are not shown. Furthermore, some of the configurations of one embodiment may be deleted, replaced with the configurations of another embodiment, or combined with the configurations of other embodiments. [Explanation of Symbols]

[0167] 1,2,3,4,5,6,7 Battery, 10 Charge / Discharge Assembly, 11b Positive Electrode Tab, 12b Negative Electrode Tab, 21 Positive Current Collector Plate (First Current Collector), 22 Negative Electrode Current Collector Plate (First Current Collector), 23 Positive Ribbon (Second Current Collector), 24 Negative Ribbon (Second Current Collector), 110 Charge / Discharge Assembly, 121 Positive Current Collector Plate (First Current Collector), 122 Negative Electrode Current Collector Plate (First Current Collector), 210 Charge / Discharge Assembly, 211b Positive Electrode Tab, 212b Negative Electrode Tab, 221 Positive Current Collector Plate (First Current Collector), 222 Negative Electrode Current Collector Plate (First Current Collector), 222f Negative Electrode Junction (Junction), 223 Positive electrode current collector plate (first current collector), 223f Positive electrode junction (junction), 224 Positive electrode current collector plate (first current collector), 224f Positive electrode junction (junction), 225 Positive electrode current collector plate (first current collector), 225f Positive electrode junction (junction), 310 Charge / discharge unit, 311b Positive electrode tab (electrode tab), 312b Negative electrode tab (electrode tab), 322 Negative electrode current collector plate (first current collector), 322f Negative electrode junction (junction), 410 Charge / discharge unit, 411b Positive electrode tab (electrode tab), 412b Negative electrode tab (electrode tab).

Claims

1. A first current collector having a first welded portion, A charge / discharge body including an electrode tab having a tab weld portion which is a weld portion laminated on the first weld portion of the first current collector, A second current collector having a second welded portion which is a welded portion laminated on the tab welded portion of the electrode tab and has a larger heat capacity than the tab welded portion, It has, The first weld portion of the first current collector, the tab weld portion of the electrode tab, and the second weld portion of the second current collector are welded from the side of the second weld portion of the second current collector. The second welded portion has a thickness along the lamination direction that is greater than that of the tab welded portion. The first current collector, the electrode tab, and the second current collector are formed from the same or the same type of material. The following conditions (A) or (B) are met: (A) The welded portion of the electrode tab has a smaller heat capacity than the first welded portion of the first current collector, and the second welded portion of the second current collector has a smaller heat capacity than the first welded portion of the first current collector. (B) The first welded portion has a thickness along the lamination direction that is greater than that of the tab welded portion, and the second welded portion has a thickness along the lamination direction that is thinner than that of the first welded portion. battery.

2. The electrode tabs are included in a plurality in the charge / discharge body. The electrode tabs of the same polarity are stacked in the stacking direction. The battery according to claim 1.

3. The first current collector, the electrode tab, and the second current collector are formed from the same or the same type of material. The battery according to claim 1.

4. The first current collector, the electrode tab, and the second current collector are formed of aluminum or an aluminum alloy. The battery according to claim 3.

5. The first welded portion of the first current collector is provided with a convex joint, The joint portion of the first current collector, the tab weld portion of the electrode tab, and the second weld portion of the second current collector are welded together. The battery according to any one of claims 1 to 4.

6. The joint portion has one of the following shapes: triangular, trapezoidal, arc-shaped, or arc-shaped with a flat portion at its leading edge. The battery according to claim 5.

7. A first current collector having a first welded portion, A charge / discharge body including an electrode tab having a tab weld portion which is a weld portion laminated on the first weld portion of the first current collector, A second current collector having a second welded portion which is a welded portion laminated on the tab welded portion of the electrode tab and has a larger heat capacity than the tab welded portion, A method for manufacturing a battery having, The process includes welding the first weld portion of the first current collector, the tab weld portion of the electrode tab, and the second weld portion of the second current collector from the side of the second weld portion of the second current collector. The second welded portion has a thickness along the lamination direction that is greater than that of the tab welded portion. The first current collector, the electrode tab, and the second current collector are formed from the same or the same type of material. The following conditions (A) or (B) are met: (A) The welded portion of the electrode tab has a smaller heat capacity than the first welded portion of the first current collector, and the second welded portion of the second current collector has a smaller heat capacity than the first welded portion of the first current collector. (B) The first welded portion has a thickness along the lamination direction that is greater than that of the tab welded portion, and the second welded portion has a thickness along the lamination direction that is thinner than that of the first welded portion. Battery manufacturing method.

8. In the above process, laser welding accompanied by wobbling is performed. A method for manufacturing a battery according to claim 7.

9. Using the first current collector having a convex joint portion in the first welded portion, In the above step, the joint portion of the first current collector, the tab weld portion of the electrode tab, and the second weld portion of the second current collector are welded. A method for manufacturing a battery according to claim 7 or 8.

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