Electricity storage device and method for manufacturing the same

Abstract

To provide a power storage device that can achieve reduction in the number of components as compared with a power storage device configured such that a positive electrode external terminal and a negative electrode external terminal are each insulated from a case.SOLUTION: A power storage device 1 includes a case 10 having conductivity and an electrode body 50 housed in the case 10. The electrode body 50 includes a first current collecting portion 50c and a second current collecting portion 50d having a different polar from the first current collecting portion 50c. The case 10 and the first current collecting portion 50c of the electrode body 50 are conductively connected by a swaged joint portion 61 where these are swaged and joined. The power storage device 1 includes an electrode external terminal 70 that is insulated from the case 10 and fixed to the case 10 and that is connected to the second current collecting portion 50d of the electrode body 50 inside the case 10.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device in which an electrode assembly is housed in a conductive case, and a method for manufacturing the electricity storage device. [Background technology]

[0002] Batteries are known in which an electrode assembly is housed in a conductive case. In conventional batteries, the positive and negative external terminals are fixed to the case while being insulated from the case, and are connected to the positive and negative current collectors of the electrode assembly inside the case. Patent Document 1, for example, is an example of related prior art (see Figure 1 and other figures in Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-44958 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned battery, since the positive electrode external terminal and the negative electrode external terminal are each insulated from the case, an insulating member is required for each of the positive electrode external terminal and the negative electrode external terminal, resulting in a large number of parts.

[0005] The present invention has been made in consideration of the current situation, and provides an electricity storage device that can reduce the number of parts compared to an electricity storage device in which the positive electrode external terminal and the negative electrode external terminal are each insulated from the case. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problem is an electricity storage device including a conductive case and an electrode body housed in the case, wherein the electrode body has a first current collector and a second current collector having a polarity opposite to that of the first current collector, and the case and the first current collector of the electrode body are electrically connected to each other at a crimped joint, and the device includes an external electrode terminal that is insulated from the case, fixed to the case, and connected to the second current collector of the electrode body within the case. The case is made of a metal plate, and the crimped joint portion has a shape in which the case is recessed inward in the plate thickness direction. It is an electricity storage device.

[0007] In the above-described electricity storage device, the case is electrically connected to the first current collecting portion of the electrode assembly and also serves as one of the electrode external terminals, so no insulating member is required. This allows for a smaller number of components than electricity storage devices in which the positive electrode external terminal and the negative electrode external terminal are each insulated from the case. Furthermore, since the case and the first current collecting portion of the electrode assembly are electrically connected by a crimped joint, the case and the first current collecting portion of the electrode assembly can be appropriately electrically connected. Furthermore, in the above-described electricity storage device, the crimped joint between the case and the first current collector of the electrode assembly is recessed inward, and the crimped joint does not protrude outward from the case, so the formation of the crimped joint does not impede the freedom of arrangement of the electricity storage device.

[0008] Examples of the "electricity storage device" include secondary batteries such as lithium ion secondary batteries, sodium ion secondary batteries, and calcium ion secondary batteries, and capacitors such as lithium ion capacitors. Examples of a "crimped joint" include a crimped joint in which a metal member (such as a metal plate or metal ring) is placed on top of the first current collecting portion of the electrode body, the first current collecting portion is sandwiched between the case and the metal member, and the case, first current collecting portion, and metal member are crimped together; and a crimped joint in which the first current collecting portion of the electrode body is welded to a metal member (such as a metal plate), this metal member is placed on top of the case, and the case, metal member, and first current collecting portion are crimped together.

[0011] ( 2 )Furthermore(1 ) The described electricity storage device may be an electricity storage device formed by welding a case joint portion of the case that forms the crimp joint portion and a current collecting joint portion of the first current collecting portion of the electrode body that forms the crimp joint portion.

[0012] In the above-mentioned energy storage device, the case joint that forms the crimped joint of the case and the current collecting joint that forms the crimped joint of the first current collecting part of the electrode body are not only crimped but also welded, so that the case and the first current collecting part can be reliably connected electrically with particularly low resistance.

[0013] ( 3 In still another aspect, there is provided a device comprising a conductive case and an electrode body housed in the case, the electrode body having a first current collecting portion and a second current collecting portion having a polarity opposite to that of the first current collecting portion, the case and the first current collecting portion of the electrode body being electrically connected by a crimped joint portion where the case and the first current collecting portion of the electrode body are crimped together, and an external electrode terminal insulated from the case and fixed to the case and connected to the second current collecting portion of the electrode body within the case. The case is made of a metal plate, and the first current collecting portion of the electrode body is made of first current collecting foils stacked in the foil thickness direction. a crimping step of crimping the case and the first current collecting portion of the electrode body to form the crimped joint. The crimping step uses a die having a recess and a punch having a tip, stacks the case and the first current collecting part in a position where the plate thickness direction of the case and the foil thickness direction are aligned, positions the case on the punch side and the first current collecting part on the die side, and places the case between the tip of the punch and the recess of the die, and moves the tip of the punch toward the recess of the die to crimp and join the case and the first current collecting part. This is a method for manufacturing an electricity storage device.

[0014] When joining the case and the first current collector of the electrode body, for example, by irradiating the first current collector of the electrode body with a laser beam to laser-weld the first current collector of the electrode body to the case, spatter-induced metallic foreign matter is generated inside the case. Such metallic foreign matter can cause an internal short circuit. In contrast, in the manufacturing method of the above-described electricity storage device, the case and the first current collector of the electrode body are electrically connected by performing a crimping joint in the crimping process, so that the above-described generation of metallic foreign matter and the occurrence of an internal short circuit are not generated, and the case and the first current collector of the electrode body can be properly joined. Furthermore, in the manufacturing method of the electricity storage device described above, by performing the crimping step using a die and a punch as described above, the crimped joint between the case and the first current collector of the electrode assembly has a shape in which the case is recessed inward, so that the formation of the crimped joint does not impede the degree of freedom in the placement of the electricity storage device, etc.

[0017] ( 4 )Furthermore( 3) The manufacturing method of the described electricity storage device may preferably further include a crimping portion welding process for welding a case joint that forms the crimping joint of the case to a current collecting joint that forms the crimping joint of the first current collecting portion of the electrode body.

[0018] In the manufacturing method of the above-mentioned energy storage device, the case joint that forms the crimp joint of the case and the current collecting joint that forms the crimp joint of the first current collecting part of the electrode body are not only crimped together in the crimping process, but are also welded together in the crimping part welding process, so that the case and the first current collecting part can be reliably connected electrically with particularly low resistance.

[0019] ( 5 )Furthermore( 4 In the method for manufacturing an electric storage device described in the above, the crimping portion welding step may be a method for manufacturing an electric storage device in which laser light is irradiated from the outside of the case toward the case joint portion to laser-weld the case joint portion to the current collecting joint portion.

[0020] In the manufacturing method of the above-mentioned energy storage device, laser light is irradiated from the outside of the case toward the case joint, and the case joint is laser welded to the current collecting joint of the first current collecting part, thereby preventing the generation of metal foreign matter caused by sputtering inside the case. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment. [Figure 2] 1 is a partially cutaway cross-sectional view of a battery according to an embodiment, taken along the case height direction and the case width direction. [Figure 3] 3 is a cross-sectional view taken along the arrows AA in FIGS. 1 and 2, taken along the case height direction and case thickness direction of the battery according to the embodiment. FIG. [Figure 4] 4 is a partially enlarged cross-sectional view of the vicinity of the crimped joint in FIG. 3 in the battery according to the embodiment. [Figure 5] 3 is a cross-sectional view taken along the arrow BB in FIGS. 1 and 2, taken along the case height direction and case thickness direction of the battery according to the embodiment. FIG. [Figure 6] 3 is a flowchart of a method for manufacturing a battery according to an embodiment. [Figure 7]10 is an explanatory diagram showing how the negative electrode current collecting portion of the electrode body is laser-welded to the negative electrode external terminal fixed to the case body member in the terminal connecting step in the manufacturing method of the battery according to the embodiment. FIG. [Figure 8] 10 is an explanatory diagram showing the state in which the electrode body is housed in the case body member, in relation to the manufacturing method of the battery according to the embodiment. FIG. [Figure 9] FIG. 10 is an explanatory diagram showing the arrangement of a punch and a die in a crimping step in the method for manufacturing a battery according to the embodiment. [Figure 10] 10A and 10B are explanatory views showing how the case, the positive electrode current collector of the electrode body, and the metal plate are crimped together using a punch and a die in a crimping step in the method for manufacturing a battery according to the embodiment. [Figure 11] 10 is an explanatory diagram showing how a case joint, a current collector joint, and a metal plate joint that form a crimped joint are laser-welded in a crimped portion welding step in a manufacturing method of a battery according to an embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a perspective view of a battery (power storage device) 1 according to this embodiment, and Figs. 2 to 5 show cross-sectional views of the battery 1. In the following description, the case height direction AH, case width direction BH, and case thickness direction CH of the battery 1 will be defined as the directions shown in Figs. 1 to 5. The battery 1 is a prismatic (rectangular) sealed lithium ion secondary battery that is installed in vehicles such as hybrid cars, plug-in hybrid cars, and electric cars.

[0023] The battery 1 is composed of a case 10 at a positive electrode potential, a laminated electrode assembly 50 housed in the case 10, and a negative electrode external terminal (external electrode terminal) 70 supported in an insulated manner by the case 10. The electrode assembly 50 is covered in a bag-shaped insulating holder (not shown) made of insulating film inside the case 10. An electrolyte 3 is also housed inside the case 10, a portion of which is impregnated into the electrode assembly 50 and the remainder of which is collected on a second side wall portion 14, which is the bottom wall portion of the case 10.

[0024] The case 10 is made of a metal plate (an aluminum plate in this embodiment) and is conductive. The case 10 has a rectangular box shape and includes a first main wall portion 11, a second main wall portion 12, and four side walls 13 to 16 (first side wall portion 13, second side wall portion 14, third side wall portion 15, and fourth side wall portion 16), each of which is rectangular. The first main wall portion 11 and the second main wall portion 12 have a larger area than the side walls 13 to 16. The first main wall portion 11 and the second main wall portion 12 face each other, with the first main wall portion 11 located on one side CH1 in the case thickness direction CH (the front right side in FIG. 1, the left side in FIGS. 3 and 5), and the second main wall portion 12 located on the other side CH2 in the case thickness direction CH (the rear left side in FIG. 1, the right side in FIGS. 3 and 5).

[0025] Meanwhile, the side walls 13-16 each extend in the case thickness direction CH, connecting the first main wall 11 and the second main wall 12. The first side wall 13 and the second side wall 14 face each other, with the first side wall 13 located on an upper side AH1 in the case height direction AH and the second side wall 14 located on a lower side AH2 in the case height direction AH. The third side wall 15 and the fourth side wall 16 face each other, with the third side wall 15 located on one side BH1 in the case width direction BH and the fourth side wall 16 located on the other side BH2 in the case width direction BH.

[0026] The case 10 is a rectangular cylindrical case with a bottom and a rectangular opening 21c, and is configured from a case body member 21 that houses the electrode assembly 50 therein, and a rectangular plate-like lid member 31 that closes the opening 21c of the case body member 21. Of these, the case body member 21 forms the second main wall portion 12 and four side wall portions 13 to 16. On the other hand, the lid member 31 forms the first main wall portion 11, and a lid peripheral portion 31f of the lid member 31 and an opening peripheral portion 21f of the opening 21c of the case body member 21 are airtightly joined (welded in this embodiment) around the entire periphery.

[0027] First side wall 13, which is also the upper wall of case 10, is provided with safety valve 17 that ruptures and opens when the internal pressure of case 10 exceeds a valve opening pressure. First side wall 13 is also provided with liquid inlet 13k that penetrates first side wall 13, and liquid inlet 13k is airtightly sealed with a disk-shaped sealing member 18 made of aluminum. Furthermore, a negative electrode external terminal 70 made of copper is fixed to the first side wall portion 13 near the end portion on the other side BH2 in the case width direction BH. Specifically, an insertion hole 13h penetrating the first side wall portion 13 is provided near the end portion on the other side BH2 in the case width direction BH of the first side wall portion 13, and the negative electrode external terminal 70 is inserted into this insertion hole 13h and extends from the inside of the case 10 to the outside of the case 10. The negative electrode external terminal 70 is conductively connected to a negative electrode current collecting portion 50d of the electrode body 50 (described later) within the case 10. The negative electrode external terminal 70 and the first side wall portion 13 are insulated from each other via an insulating portion 65. The insulating portions 65 are each made of insulating resin and consist of an external resin member 66 located on the outside of the first side wall portion 13 and inside the insertion hole 13h, and an internal resin member 67 located on the inside of the first side wall portion 13 (inside the case 10).

[0028] Next, the electrode assembly 50 will be described. The electrode assembly 50 is a rectangular parallelepiped laminated type, in which a plurality of positive electrode plates (first electrode plates) 51 and a plurality of negative electrode plates (second electrode plates) 54 are alternately laminated in the case thickness direction CH with separators 57 made of porous resin films interposed therebetween. The positive electrode plates 51, negative electrode plates 54, and separators 57 each have a rectangular shape extending in the case height direction AH and the case width direction BH.

[0029] The positive electrode plate 51 includes a positive electrode current collector foil (first current collector foil) 52 made of aluminum foil and a positive electrode active material layer (first active material layer) 53 formed on each of the two main surfaces of the positive electrode current collector foil 52. The positive electrode active material layer 53 contains positive electrode active material particles capable of absorbing and releasing lithium ions. A portion of the positive electrode current collector foil 52 extends toward the upper side AH1 near an end of one side BH1 in the case width direction BH. Both sides of the positive electrode current collector foil 52 are exposed and free of the positive electrode active material layer 53, forming a positive electrode foil exposed portion (first foil exposed portion) 52r. The positive electrode foil exposed portion 52r of each positive electrode plate 51 overlaps with the foil thickness direction EH to form a positive electrode current collector portion (first current collector portion) 50c. The positive electrode current collector portion 50c is electrically connected to the case 10 by crimping, as described below.

[0030] The negative electrode plate 54 includes a negative electrode current collector foil (second current collector foil) 55 made of copper foil and a negative electrode active material layer (second active material layer) 56 formed on each of the two main surfaces of the negative electrode current collector foil 55. The negative electrode active material layer 56 contains negative electrode active material particles capable of absorbing and releasing lithium ions. A portion of the negative electrode current collector foil 55 extends toward the upper side AH1 near the end of the other side BH2 in the case width direction BH. The negative electrode active material layer 56 is not present on either side of the negative electrode current collector foil 55, forming a negative electrode foil exposed portion (second foil exposed portion) 54r. The negative electrode foil exposed portion 54r of each negative electrode plate 54 overlaps the foil thickness direction FH to form a negative electrode current collector portion (second current collector portion) 50d. The negative electrode current collector portion 50d is electrically connected to a negative electrode external terminal 70 by welding.

[0031] The positive electrode current collecting portion 50c of the electrode body 50 and the second main wall portion 12 of the case 10 are electrically connected by two crimped joints 61 that crimp them together. These crimped joints 61 are formed on the second main wall portion 12 near the end of an upper side AH1 in the case height direction AH and on one side BH1 in the case width direction BH. In this embodiment, the crimp joint 61 is formed by placing a metal plate (metal member) 63 made of a rectangular aluminum plate on the positive current collector 50c, sandwiching the positive current collector 50c between the second main wall 12 and the metal plate 63, and crimping the second main wall 12, the positive current collector 50c, and the metal plate 63. By crimping the positive current collector 50c between the second main wall 12 and the metal plate 63 in this manner, rather than simply stacking and crimping the second main wall 12 and the positive current collector 50c alone, these can be reliably crimped together.

[0032] The crimped joint 61 has a shape in which the case 10 is recessed inward DH1 in the plate thickness direction DH. Specifically, of the second main wall portion 12 of the case 10, a case joint 12g forming the crimped joint 61 is circular in plan view and recessed inward DH1 in the plate thickness direction DH into the interior of the case 10. Furthermore, of the positive electrode current collector 50c of the electrode assembly 50, a current collecting joint 50cg forming the crimped joint 61 is also circular in plan view and recessed inward in the foil thickness direction EH into the interior of the case 10. Furthermore, of the metal plate 63, a metal plate joint 63g forming the crimped joint 61 is also circular in plan view and recessed inward in the case 10. Furthermore, at the center of the crimped joint 61, the case joint 12g, the current collecting joint 50cg, and the metal plate joint 63g are welded to one another at a weld 61y.

[0033] As described above, the battery 1 does not require an insulating member because the case 10 is electrically connected to the positive current collector 50c of the electrode assembly 50 and also serves as the positive external terminal. This allows for a smaller number of parts compared to a battery in which the positive external terminal and the negative external terminal are each insulated from the case. Furthermore, the case 10 and the positive current collector 50c of the electrode assembly 50 are electrically connected by the crimped joint 61, ensuring appropriate electrical connection between the case 10 and the positive current collector 50c.

[0034] Furthermore, in this embodiment, the crimped joint 61 is recessed toward the inside DH1 of the case 10, and does not protrude toward the outside DH2 of the case 10. Therefore, the formation of the crimped joint 61 does not impede the freedom of arrangement of the battery 1, etc. Furthermore, the case joint 12g forming the crimped joint 61 of the case 10 and the collector joint 50cg forming the crimped joint 61 of the positive electrode collector 50c of the electrode body 50 are not only crimped but also welded (the welded part 61y is formed at the crimped joint 61), so that the case 10 and the positive electrode collector 50c can be reliably connected electrically with particularly low resistance.

[0035] Next, a method for manufacturing the battery 1 will be described (see Figs. 6 to 11). Figs. 7 and 8 are explanatory cross-sectional views corresponding to Fig. 5, Fig. 9 is an explanatory cross-sectional view corresponding to Fig. 3, and Figs. 10 and 11 are explanatory cross-sectional views corresponding to Fig. 4. First, the case body member 21 is prepared, and the negative external terminal 70 is fixed to the first side wall portion 13 of this case body member 21. Furthermore, a positive electrode plate 51, a negative electrode plate 54, and a separator 57 are stacked to form an electrode body 50 having a positive electrode current collector 50c and a negative electrode current collector 50d, and the electrode body 50 is wrapped in a bag-shaped insulating holder (not shown).

[0036] Then, in the "terminal connecting step S1" (see FIG. 6), the negative electrode current collector 50d of the electrode assembly 50 is connected to the negative electrode external terminal 70 fixed to the case body member 21 (see FIG. 7). Specifically, with the negative electrode current collector 50d of the electrode assembly 50 abutting against the negative electrode external terminal 70 from the lower side AH2 to the upper side AH1 in the case height direction AH, laser light LC is irradiated toward the negative electrode current collector 50d from the lower side AH2 to the upper side AH1, and the negative electrode current collector 50d is laser-welded to the negative electrode external terminal 70. Thereafter, the electrode assembly 50 is bent at the negative electrode current collector 50d, and the electrode assembly 50 is housed in the case body member 21 (see FIG. 8).

[0037] Next, in the "crimping step S2" (see FIG. 6), the second main wall portion 12 of the case 10, the positive electrode current collecting portion 50c of the electrode body 50, and the metal plate 63 are crimped together to form a crimped joint 61 (see FIGS. 9 and 10). This crimping step S2 is performed using a die DE having a recess DEh that is circular in plan view, and a punch PT having a cylindrical tip portion PTs whose outer diameter is smaller than the inner diameter of the recess DEh of the die DE. First, the second main wall portion 12 of the case 10, the positive current collector 50c of the electrode body 50, and the metal plate 63 are placed between the tip portion PTs of the punch PT and the recess DEh of the die DE (see FIG. 9 ). Specifically, the second main wall portion 12 of the case 10, the positive current collector 50c of the electrode body 50, and the metal plate 63 are stacked in an orientation in which the plate thickness direction DH of the second main wall portion 12 and the foil thickness direction EH of the positive current collector foil 52 of the positive current collector 50c are aligned, and the second main wall portion 12 of the case 10 is placed on the punch PT side, and the metal plate 63 and the positive current collector 50c are placed on the die DE side.

[0038] Thereafter, the tip portion PTs of the punch PT is moved toward the recessed portion DEh of the die DE, and the tip portion PTs of the punch PT and the recessed portion DEh of the die DE crimp-join the second main wall portion 12 of the case 10, the positive current collector 50c, and the metal plate 63 (see FIG. 10 ). This forms a crimped joint 61 consisting of the case joint portion 12g of the second main wall portion 12, the current collector joint portion 50cg of the positive current collector 50c, and the metal plate joint portion 63g of the metal plate 63. Next, the positions of the punch PT and the die DE are shifted in the case width direction BH, and crimping is performed in the same manner to form the other crimped joint 61. In this way, the second main wall portion 12 of the case 10 and the positive current collector 50c of the electrode assembly 50 are electrically connected by the two crimped joints 61.

[0039] Next, in a "crimping portion welding step S3" (see FIG. 6), a case joint 12g forming the crimping joint 61 of the second main wall portion 12 of the case 10, a current collecting joint 50cg forming the crimping joint 61 of the positive current collecting portion 50c of the electrode body 50, and a metal plate joint 63g forming the crimping joint 61 of the metal plate 63 are welded together (see FIG. 11). Specifically, for each of the two crimping joints 61, laser light LB is irradiated from the outside of the case 10 (from the outer side DH2 to the inner side DH1 in the plate thickness direction DH) toward the center of the case joint 12g of the second main wall portion 12, thereby laser-welding the center of the case joint 12g, the center of the current collecting joint 50cg of the positive current collecting portion 50c, and the center of the metal plate joint 63g of the metal plate 63. As a result, a welded portion 61y (see FIG. 4) is formed in the center of each crimped joint portion 61.

[0040] Next, in the "case formation process S4" (see FIG. 6), the lid member 31 is joined to the case body member 21 to form the case 10. Specifically, the lid member 31 is placed on the case body member 21, and the lid peripheral portion 31f of the lid member 31 is brought into contact with the opening peripheral portion 21f of the case body member 21 over the entire periphery. Thereafter, the lid peripheral portion 31f and the opening peripheral portion 21f are laser-welded airtightly over the entire periphery to form the case 10. Next, in the "pouring and sealing step S5," the electrolyte 3 is poured into the case 10 through the pouring hole 13k, and the electrolyte 3 is impregnated into the electrode body 50. Thereafter, the pouring hole 13k is covered from the outside with a sealing member 18, and the sealing member 18 is laser-welded to the case 10 in an airtight manner. Next, in the "initial charging and aging step S6," a charging device (not shown) is connected to the battery 1, and the battery 1 is initially charged. After that, the initially charged battery 1 is left to stand for a predetermined time to age the battery 1. In this way, the battery 1 is completed.

[0041] Incidentally, when joining the case 10 and the positive current collector 50c of the electrode body 50, for example, by irradiating the positive current collector 50c of the electrode body 50 with a laser beam to laser-weld the positive current collector 50c of the electrode body 50 to the case 10, sputtering can generate metallic foreign matter inside the case 10. Such metallic foreign matter can cause an internal short circuit. In contrast, in the manufacturing method of the battery 1, crimping is performed in the crimping step S2 to electrically connect the case 10 and the positive current collector 50c of the electrode body 50. This prevents the generation of metallic foreign matter and the resulting internal short circuit, and allows the case 10 and the positive current collector 50c of the electrode body 50 to be properly joined. Furthermore, in this embodiment, by performing the crimping step S2 using the punch PT and die DE as described above, the crimped joint 61 is formed by recessing the second main wall portion 12 of the case 10 toward the inside DH1. Therefore, the formation of the crimped joint 61 does not impede the freedom of arrangement of the battery 1, etc.

[0042] In addition, in this embodiment, the case joint 12g, which forms the crimp joint 61 of the second main wall portion 12 of the case 10, and the collector joint 50cg, which forms the crimp joint 61 of the positive electrode collector portion 50c of the electrode body 50, are not only crimped and joined in the crimping process S2, but are also welded in the crimping portion welding process S3, so that the second main wall portion 12 of the case 10 and the positive electrode collector portion 50c can be reliably connected electrically with particularly low resistance. Furthermore, in the crimping portion welding process S3, laser light LB is irradiated from the outside of the case 10 toward the case joint 12g, and the case joint 12g is laser-welded to the current collecting joint 50cg of the positive electrode current collecting portion 50c, so that this welding can prevent the generation of metal foreign matter caused by sputtering inside the case 10.

[0043] Although the present invention has been described above in accordance with the embodiments, it goes without saying that the present invention is not limited to the embodiments and can be modified and applied as appropriate within the scope of the invention. For example, in the embodiment, the crimped joint 61 is provided in the second main wall portion 12 of the case 10, but this is not limited to this. The crimped joint 61 may be provided in another portion of the case 10 (such as the first main wall portion 11 or the first side wall portion 13).

[0044] In the embodiment, the battery 1 is exemplified as one in which the case 10 is at a positive electrode potential, but the battery can also be one in which the case 10 is at a negative electrode potential. That is, the case 10 and the negative electrode current collector of the electrode body are electrically connected at a crimped joint where they are joined. Meanwhile, the positive electrode external terminal is fixed to the case 10 while being insulated from the case 10, and the positive electrode current collector of the electrode body is electrically connected to the positive electrode external terminal inside the case 10. [Explanation of symbols]

[0045] 1. Battery (energy storage device) 10 cases 12g Case joint 50 Electrode body 50c Positive electrode current collector (first current collector) 50cg current collector joint 50d Negative electrode current collector (second current collector) 51 positive electrode plate (first electrode plate) 52 Positive current collecting foil (first current collecting foil) 52r Positive electrode foil exposed part (first foil exposed part) 54 Negative electrode plate (second electrode plate) 55 Negative electrode current collecting foil (second current collecting foil) 55r Exposed negative foil area (exposed second foil area) 61 Crimped joint 61y Welded Part 65 Insulation section 66 External resin parts 67 Internal resin parts 70 Negative external terminal (electrode external terminal) DH (case) thickness direction DH1 (thickness direction) inner side DH2 (thickness direction) outside EH (Positive electrode current collector foil) foil thickness direction LB, LC laser light DE Die DEh (die) recess PT Punch PTs (punch) tip S2 crimping process S3 Crimping part welding process

Claims

1. An electricity storage device comprising a conductive case and an electrode assembly housed in the case, The electrode body is a first current collecting portion and a second current collecting portion having a polarity opposite to that of the first current collecting portion, the case and the first current collecting portion of the electrode body are electrically connected by a crimped joint portion where they are crimped together, an external electrode terminal insulated from the case, fixed to the case, and connected to the second current collecting portion of the electrode body within the case; the case is made of a metal plate, The crimped joint portion has a shape in which the case is recessed inward in the plate thickness direction. Energy storage device.

2. The electricity storage device according to claim 1 , a case joint portion of the case that forms the crimped joint portion and a current collecting joint portion of the first current collecting portion of the electrode body that forms the crimped joint portion are welded together; Energy storage device.

3. The device comprises a conductive case and an electrode body housed in the case, The electrode body is a first current collecting portion and a second current collecting portion having a polarity opposite to that of the first current collecting portion, the case and the first current collecting portion of the electrode body are electrically connected by a crimped joint portion where they are crimped together, an external electrode terminal insulated from the case, fixed to the case, and connected to the second current collecting portion of the electrode body within the case; the case is made of a metal plate, The first current collecting portion of the electrode body is formed by stacking first current collecting foils in the foil thickness direction. A method for manufacturing an electricity storage device, comprising: a crimping step of crimping the case and the first current collecting portion of the electrode body to form the crimped joint, The crimping step includes: Using a die having a recess and a punch having a tip, The case and the first current collecting portion are stacked in a position where the plate thickness direction of the case coincides with the foil thickness direction, and the case is positioned on the punch side and the first current collecting portion is positioned on the die side, and the case and the first current collecting portion are disposed between the tip of the punch and the recess of the die, The tip of the punch is moved toward the recess of the die to crimp the case and the first current collecting portion. A method for manufacturing an electricity storage device.

4. A method for manufacturing the electricity storage device according to claim 3, comprising: The method further includes a crimping portion welding step of welding a case joint portion of the case that forms the crimping joint portion to a current collecting joint portion of the first current collecting portion of the electrode body that forms the crimping joint portion. A method for manufacturing an electricity storage device.

5. A method for manufacturing the electricity storage device according to claim 4, comprising: The crimped portion welding step includes: A laser beam is irradiated from the outside of the case toward the case joint portion, and the case joint portion is laser-welded to the current collecting joint portion. A method for manufacturing an electricity storage device.

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