JP5751203B2 - Power storage device and secondary battery - Google Patents

Description

  The present invention relates to a power storage device and a secondary battery, and more particularly to a power storage device and a secondary battery that are characterized by an electrode sheet joining structure.

  Power storage devices such as secondary batteries and capacitors are widely used as power sources because they can be recharged and can be used repeatedly. In general, a power storage device having a large capacity includes a case for accommodating an electrode body, and the electrode body is accommodated in the case. The electrode body has a rectangular electrode sheet and a negative electrode sheet alternately stacked with a separator interposed therebetween, and a positive electrode sheet and a negative electrode sheet formed in a strip form a separator. There is a wound-type electrode body that is formed by being sandwiched and wound into a substantially long cylindrical shape.

  The electric power is taken out from the electrode body through electrode terminals connected to the positive electrode sheet and the negative electrode sheet. Therefore, in order to electrically connect the positive electrode sheet and the negative electrode sheet to the positive electrode terminal and the negative electrode terminal, it is necessary to weld the positive electrode sheet and the negative electrode sheet to each other. When the amount of electric power to be taken out from the stacked electrode body is increased, the number of positive electrode sheets and negative electrode sheets is several tens or more. Further, even in the wound electrode body, the number of layers (laminated portions) where the belt-like positive electrode sheet and the negative electrode sheet are wound and overlapped is several tens or more.

  However, as shown in FIG. 7 in a state where the number of electrode sheets to be welded is large, even if spot welding is performed with a large number of metal foil portions 51 sandwiched between a pair of welding electrode rods 52a and 52b, A large number of metal foil portions 51 cannot be welded. For example, if the welding electrode rods 52a and 52b are made of copper during welding of an aluminum foil, the aluminum melts and adheres to the welding rod. Further, if the welding electrode rods 52a and 52b are made of carbon, a large current cannot flow, so the number of foils that can be welded is reduced.

  Conventionally, a plurality of positive current collecting tabs and a plurality of negative current collecting tabs drawn in the same direction from a laminate in which a positive electrode and a negative electrode are opposed to each other via a separator are respectively connected to a positive lead terminal and a negative lead terminal. When connecting by welding, a method has been proposed in which welding is performed by shifting the welding position by the number of weldable sheets (see Patent Document 1). In this method, as shown in FIGS. 8A and 8B, a plurality of positive current collecting tabs 55 and a plurality of negative current collecting tabs (not shown) drawn from the laminate 54 in the same direction are respectively connected to positive lead terminals. 56 and the negative electrode lead terminal (not shown) are welded by shifting the welding position by the number of weldable sheets.

  In addition, a method of manufacturing a laminate is proposed in which a component having an outer contour corresponding to the cross-sectional shape of the laminate is formed by punching a plate material, and the components are sequentially laminated and integrated (Patent Document 2). reference). In this method, as shown in FIG. 9A, the component member 58 is stamped and formed, and a clearance hole 59 is formed through the component member 58, and a plurality of component members 58 are stacked to emit laser light. The two constituent members 58 are welded and integrated through the welded portion 60. As a result of this welding, a weld swell 61 is formed at the upper end of the weld 60. Thereafter, the component member 58 to be laminated thereon is laminated and pressed so that the escape hole 59 coincides with the weld bulge portion 61 of the lower component member 58, and is moved to a position other than the escape hole 59 of the component member 58. Laser light is emitted and integrated sequentially.

  In addition, a method of manufacturing an iron core has also been proposed in which a core punched by a press is laser welded (see Patent Document 3). In the iron core 63 manufactured by this method, as shown in FIG. 9B, a weld hole 64 and a punched plate 66 having a weld escape hole 65 aligned with the weld hole 64 are joined by a weld portion 67. . The iron core 63 is manufactured by moving a welding hole 64 and a punch plate 66 having a welding escape hole 65 in parallel with the welding hole 64 to move the welding hole 64 for each lamination and laser welding from the welding hole 64 for each lamination. The weld side at the weld hole 64 of the punched plate 66 and the weld escape hole 65 of the punched plate 66 to be stacked are aligned and stacked, and then laser welding is performed from the weld hole 64 of the stacked punched plate 66. Repeat that.

JP 2008-66170 A Japanese Patent Laid-Open No. 10-244650 JP-A-10-31556

  In the method described in Patent Document 1, the positive electrode current collecting tab 55 and the negative electrode current collecting tab are divided into a plurality of groups each having a number that can be welded, and the positive electrode current collecting tab 55 and the negative electrode current collecting tab of each group are positive electrode leads. The welding location with respect to the terminal 56 or the negative electrode lead terminal is shifted and connected. Therefore, when the number of the positive electrode current collecting tabs 55 and the negative electrode current collecting tabs increases, it is necessary to secure a large welding area for the positive electrode lead terminal 56 or the negative electrode lead terminal.

  Moreover, since the method of patent document 2 and patent document 3 joins the member thicker than metal foil with a welding part, and laminates and integrates, the component member 58 and the punching board 66 which are the members laminated | stacked are 1 Laser welding is repeated with the sheets stacked one by one. Therefore, it takes time to weld a large number of sheets, and no consideration is given to the integration of a thin and large number of sheets such as a metal foil portion of an electrode sheet. Laser welding has higher equipment costs than spot welding, and it is difficult to weld a material having high reflection such as aluminum or aluminum alloy.

  The present invention has been made in view of the above-described problems, and an object of the present invention is an electrode configured by welding a plurality of positive electrode sheets as electrode sheets and metal foil portions of the plurality of negative electrode sheets by welding. An object of the present invention is to provide a power storage device and a secondary battery having an electrode body capable of welding all metal foil portions in an electrically connected state without any trouble even when the number of metal foil portions of the body is large.

  In order to achieve the above object, an invention according to claim 1 is an electricity storage comprising an electrode body joined by spot welding in a state in which a plurality of positive electrode sheets as electrode sheets and a plurality of metal foil portions of negative electrode sheets are laminated. Device. And the said metal foil part of the said electrode sheet is the 1st outermost group and 2nd outermost group which are each arrange | positioned on the outermost side of the lamination direction, and 1 or more arrange | positioned between both outermost groups The intermediate group is composed of a plurality of the metal foil portions, and the metal foil portions of two adjacent groups are joined together by a welded portion, and the metal foil portions of all the positive electrode sheets and all of the above-mentioned metal foil portions are joined together. The metal foil portions of the negative electrode sheet are electrically connected to each other. The metal foil part of the electrode sheet constituting at least one of the first outermost group and the second outermost group is a position of the welded part formed in the metal foil part of the adjacent intermediate group. The metal foil portion formed in the stacking direction at the position of the welded portion is formed in the metal foil portion of the intermediate group and the metal of one group adjacent to the intermediate group. Only the foil part.

  In the present invention, each of the plurality of metal foil portions includes a first outermost group and a second outermost group disposed on the outermost side, and one or more intermediate groups disposed between the two outermost groups. Is composed of a plurality of sheets, and the metal foil portions of two adjacent groups are joined by a welded portion, and the metal foil portions of all the positive electrode sheets and the metal foil portions of all the negative electrode sheets are electrically connected to each other, respectively. It is connected. Therefore, when a part of the metal foil portion of the positive electrode sheet is electrically connected to the positive electrode terminal of the power storage device via the positive electrode current collecting terminal, all the positive electrode sheets are electrically connected to the positive electrode terminal. Further, when a part of the metal foil portion of the negative electrode sheet is electrically connected to the negative electrode terminal of the power storage device via the negative electrode current collecting terminal, all the negative electrode sheets are electrically connected to the negative electrode terminal. Further, the metal foil part of the electrode sheet constituting at least one of the first outermost group and the second outermost group has a notch or a cutout part at the position of the weld formed on the metal foil part of the adjacent intermediate group. The metal foil part in which the through hole is formed and exists in the stacking direction at the position of the welded part is only the metal foil part of the intermediate group and the metal foil part of one group adjacent to the intermediate group. Therefore, even when the number of the metal foil portions of the electrode body constituted by welding the metal foil portions of the plurality of positive electrode sheets and the plurality of negative electrode sheets as the electrode sheets cannot be welded by one welding, All metal foil portions can be welded to an electrically connected state without any trouble.

  The invention according to claim 2 is the invention according to claim 1, wherein a plurality of the intermediate groups are provided. In the present invention, it is possible to easily cope with a case where the number of metal foil portions to be joined is large as compared with the case where one intermediate group is provided.

  The invention according to claim 3 is the invention according to claim 2, wherein both end portions of the welded portion in the stacking direction are not joined via the welded portion or the first outermost group. It is exposed to the notch or the through hole provided in the outermost group of 2 or the intermediate group. Therefore, in this invention, the edge part of a welding part does not protrude from the area | region of the full thickness of a metal foil part.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the welded portion is formed by arc welding. Therefore, in this invention, even if the metal foil portion is a material that is difficult to be laser-welded, such as aluminum or aluminum alloy, it can be easily welded. Also, arc welding equipment is less expensive than laser welding equipment.

  The invention according to claim 5 is a secondary battery having the structure of the power storage device according to any one of claims 1 to 4. Therefore, the secondary battery of the present invention has the same effect as that of any one of the first to fourth aspects.

  According to invention of Claim 1-5, the metal foil part of the electrode body comprised by welding the metal foil part of the some positive electrode sheet and the some negative electrode sheet as an electrode sheet by welding Even when the number of sheets is large, it is possible to provide a power storage device and a secondary battery having an electrode body that can weld all the metal foil portions to an electrically connected state without hindrance.

(A) is a schematic perspective view of the electrode body of 1st Embodiment, (b) is a schematic diagram of a positive electrode sheet, (c) is a schematic diagram of a negative electrode sheet, (d) is a schematic diagram of a separator. (A) is a schematic diagram which shows the location which wants to join in the welding part of a metal foil part, (b) is a schematic plan view which shows the joining structure of the metal foil part of an electrode sheet, (c) is a partial schematic front view of (b). (D) is a schematic plan view of the metal foil part before welding. (A) is a schematic plan view which shows the joining structure of the metal foil part of the electrode sheet of 2nd Embodiment, (b) is a partial schematic front view of (a), (c) is a schematic plan view explaining a welding procedure. . (A), (b), (c) is a schematic top view which shows the joining structure of the metal foil part of the electrode sheet in another embodiment, respectively. (A) is a schematic plan view which shows the joining structure of the metal foil part of another embodiment, (b) is a schematic front view, (c), (d) is the joining structure of the metal foil part of another embodiment, respectively. The schematic front view to show. The schematic perspective view of the electrode body of another embodiment. The schematic diagram explaining the problem in the case of spot-welding many electrode sheets. (A), (b) is a perspective view which shows a prior art. (A) is sectional drawing which shows another prior art, (b) is sectional drawing which shows another prior art.

(First embodiment)
A first embodiment embodying the present invention will be described below with reference to FIGS.
As shown in FIG. 1A, the electrode body 10 includes a plurality of positive electrode sheets 11 and a plurality of negative electrode sheets 12 as electrode sheets, and a sheet-like separator 13 interposed between the positive electrode sheet 11 and the negative electrode sheet 12. It is the laminated type electrode body laminated | stacked in the state. The positive electrode sheet 11 and the negative electrode sheet 12 are entirely formed of a metal foil such as an aluminum alloy foil or a copper foil, except for the metal foil portion that electrically connects the positive electrode sheet 11 and the negative electrode sheet 12 to the current collector terminal. An active material is applied.

  As shown in FIG. 1 (b), the positive electrode sheet 11 is formed in a substantially rectangular shape, and the convex portion 11a has a constant width from the center of one side of the rectangle to one half (right half in FIG. 1 (b)). Is formed. An active material (not shown) is applied to a portion excluding the convex portion 11a to form an active material application portion 11b, and the convex portion 11a constitutes a metal foil portion. And as shown to Fig.1 (a), in the state which comprises the electrode body 10, the convex parts 11a are joined by spot welding, and all the positive electrode sheets 11 are electrically connected.

  As shown in FIG. 1 (c), the negative electrode sheet 12 is formed in a substantially rectangular shape, and the convex portion 12a has a constant width from the center of one side of the rectangle to one half (the left half in FIG. 1 (c)). Is formed. An active material (not shown) is applied to a portion excluding the convex portion 12a to form an active material application portion 12b, and the convex portion 12a constitutes a metal foil portion. And as shown to Fig.1 (a), in the state which comprises the electrode body 10, the convex parts 12a are joined by spot welding, and all the negative electrode sheets 12 are electrically connected.

  And as shown in FIG.1 (d), the separator 13 is formed in the rectangular shape which removed the convex part 11a and the convex part 12a in the positive electrode sheet 11 and the negative electrode sheet 12. FIG. The separator 13 is formed to be slightly larger than the active material application portions 11 b and 12 b of the positive electrode sheet 11 and the negative electrode sheet 12 so that the positive electrode sheet 11 and the negative electrode sheet 12 are not short-circuited.

  When the electrode body 10 constitutes a secondary battery as a power storage device, the convex portion 11a of the positive electrode sheet 11 is welded to the positive current collector terminal and is electrically connected to the positive current collector terminal. The terminal is electrically connected to the positive terminal of the secondary battery. Further, the convex portion 12a of the negative electrode sheet 12 is welded to the negative electrode current collector terminal and electrically connected to the negative electrode current collector terminal, and is electrically connected to the negative electrode terminal of the secondary battery via the negative electrode current collector terminal. Is done. That is, the power storage device (secondary battery) includes an electrode body 10 that is joined by spot welding in a state where a plurality of metal foil portions of a positive electrode sheet 11 and a negative electrode sheet 12 as electrode sheets are laminated.

Next, the joining structure of the electrode sheet of the electrode body 10 configured as described above will be described.
When the convex portion (metal foil portion) 11a is electrically connected to the positive electrode current collector terminal, it is sufficient that the individual convex portions 11a can be collectively welded to the positive electrode current collector terminal. When the number of the parts 11a increases, it is not possible to perform welding at one place all at once. Also, the connection of the convex portion 12a to the negative electrode current collector terminal is the same. Therefore, in this embodiment, by electrically connecting some of the convex portions 11a to the positive electrode current collector terminal, all the convex portions 11a are electrically connected to the positive electrode current collector terminal. An electrode sheet joining structure in which all the convex portions 12a are electrically connected to the negative electrode current collector terminal by electrically connecting some of the convex portions 12a to the negative electrode current collector terminal. Is adopted.

  Since the bonding structure of the convex portion 11a of the positive electrode sheet 11 and the bonding structure of the convex portion 12a of the negative electrode sheet 12 are basically the same, the bonding structure of the convex portion 11a of the positive electrode sheet 11 will be described. FIG. 2 (a) shows the projections 11a and welds (joint locations) necessary to make the projections 11a (metal foil portions) of all the positive electrode sheets 11 constituting the electrode body 10 electrically connected. ) Is a schematic plan view showing the relationship with. Since the number of the convex portions 11a cannot be welded by one welding, as shown in FIG. 2 (a), the welded portion 14 has a length direction of the welded portion 14 in the stacking direction of the convex portions 11a. It is necessary to provide it at a plurality of locations with some overlapping.

  However, the position of each welded portion 14 shown in FIG. 2A is a position where one end of the welded portion 14 penetrates the convex portion 11a of the outermost layer of the stacked convex portions 11a, but the other end. The portion is located in the middle portion of the stacked convex portions 11a. Therefore, welding in which the welded portion 14 exists in the state shown in FIG.

  In this embodiment, the plurality of convex portions 11a are divided into a plurality of groups (three groups in this embodiment), and all the convex portions 11a of all the groups are welded to each other so that all the convex portions 11a of all the groups are welded. They are in an electrically connected state.

  Specifically, as shown in FIG. 2 (b), the convex portions 11a as the metal foil portions of the positive electrode sheet 11 have the first outermost group G1 and the second outermost outermost one arranged in the outermost direction in the stacking direction. The group G2 and one intermediate group G3 arranged between the two outermost groups G1, G2 are each composed of a plurality of convex portions 11a. Two adjacent groups, that is, the convex portions 11a of the first outermost group G1 and the intermediate group G3 and the second outermost group G2 and the intermediate group G3 are joined together by the welded portions 14, and all the positive electrode sheets 11 are joined. The convex portions 11a are electrically connected to each other. Two adjacent groups of convex portions 11a are joined by a plurality (two in this embodiment) of welded portions 14. Similarly, the metal foil parts (convex parts 12a) of all the negative electrode sheets 12 are electrically connected to each other.

  As shown in FIGS. 2B and 2C, the convex portion 11a of the first outermost group G1 which is one of the outermost groups G1 and G2 is the other outermost group. The total removal part 15 or the notch part 16 is formed in the location corresponding to the welding part 14 which welds a certain 2nd outermost group G2 and the intermediate | middle group G3. Further, the convex portion 11a of the second outermost group G2 which is the other outermost group corresponds to the welded portion 14 which welds the first outermost group G1 and the intermediate group G3 which are one outermost group. The total removal part 15 or the notch part 16 is formed in the location. The total removal portion 15 is a kind of cutout, which means a cutout in which the convex portion 11a is removed up to the boundary with the active material application portion 11b, and the cutout portion 16 is active around the portion corresponding to the welded portion 14. The material application part 11b is cut out to the opposite side. That is, the convex part 11a (metal foil part) of the positive electrode sheet 11 (electrode sheet) constituting at least one of the first outermost group G1 and the second outermost group G2 is a metal foil part of the adjacent intermediate group G3. A cutout portion 16 or a total removal portion 15 is formed at the position of the welded portion 14 formed in FIG. Therefore, the metal foil part which exists in the lamination direction at the position of the welded part 14 is only the metal foil part of the intermediate group G3 and one group of metal foil parts adjacent to the intermediate group.

  When manufacturing the electrode sheet bonding structure of the electrode body 10, the positive electrode sheet 11 and the negative electrode sheet 12 constituting the electrode body 10 are formed from metal foil, and the positive electrode sheets constituting the outermost groups G1 and G2. 11 and the removal part 15 and the notch part 16 are formed in the predetermined position of the convex parts 11a and 12a of the negative electrode sheet 12. Next, the positive electrode sheet 11 and the negative electrode sheet 12 are laminated with the separator 13 interposed between the adjacent positive electrode sheet 11 and negative electrode sheet 12. As a result, as shown in FIG. 2 (d), the convex portion 11a of the positive electrode sheet 11 constituting the first outermost group G1 and the intermediate group G3 and the second outermost group G2 and the intermediate group G3 is The surface opposite to the boundary between the outermost group G1 and the intermediate group G3 and the surface opposite to the boundary between the second outermost group G2 and the intermediate group G3 are in a state facing the space. Therefore, as shown by a two-dot chain line in FIG. 2D, a kind of spot welding is performed using welding rods 17a and 17b between the first outermost group G1 and the surface opposite to the boundary of the intermediate group G3. Both groups G1, G3 can be welded by arc welding. Similarly, both groups G2 and G3 can be welded by arc welding between the second outermost group G2 and the surface opposite to the boundary between the intermediate group G3 and the welding rods 17a and 17b.

  In the electrode body 10 configured as described above, the convex portions 11a and the convex portions 12a of both the outermost groups G1, G2 and the intermediate group G3 are joined to the current collecting terminals by welding, The battery case is accommodated in a state of being electrically connected to the electrode terminal of the secondary battery. And the secondary battery (single cell) as an electrical storage apparatus is comprised with electrolyte solution. Although the secondary battery is used as it is, the secondary battery is used as an assembled battery in which a plurality of single batteries are connected in series or in parallel when a high output voltage or large power is required. The assembled battery is used for various purposes. For example, the assembled battery is mounted on a vehicle as a moving body and used as a power source for a traveling motor.

According to this embodiment, the following effects can be obtained.
(1) The joining structure of the electrode sheets (positive electrode sheet 11 and negative electrode sheet 12) of the electrode body 10 is formed by laminating a plurality of metal foil portions (convex portions 11a, 12a) of the positive electrode sheet 11 and the negative electrode sheet 12 as electrode sheets. In this state, they are joined by spot welding. The metal foil portions (convex portions 11a, 12a) of the positive electrode sheet 11 and the negative electrode sheet 12 are respectively arranged on the outermost side, the first outermost group G1 and the second outermost group G2, and both outermost groups G1, G2. Each of the intermediate groups G3 arranged between each of them is composed of a plurality of sheets. Two adjacent groups, that is, the metal foil portions of the first outermost group G1 and the intermediate group G3 and between the intermediate group G3 and the second outermost group G2 are joined by the welded portion 14, and all the positive electrode sheets 11 are bonded. The metal foil portions and the metal foil portions of all the negative electrode sheets 12 are electrically connected to each other. As for the metal foil part of the electrode sheet which comprises both outermost groups G1, G2, the total removal part 15 and the notch part 16 form in the location corresponding to the welding part 14 formed in the metal foil part of the adjacent intermediate group G3. Has been. Therefore, the number of the metal foil portions of the electrode body 10 constituted by joining the metal foil portions of the plurality of positive electrode sheets 11 and the plurality of negative electrode sheets 12 as the electrode sheets by welding is so large that welding cannot be performed by one welding. Even in this case, all the metal foil portions can be welded to each other without any trouble.

  (2) The welded portion 14 is formed by arc welding. Therefore, even if the metal foil portions (projections 11a and 12a) are made of a material that is difficult to be laser-welded, such as aluminum or aluminum alloy, the metal foil portions can be easily welded. Also, arc welding equipment is less expensive than laser welding equipment.

  (3) Since two adjacent groups, that is, the first outermost group G1 and the intermediate group G3 and the second outermost group G2 and the intermediate group G3 are joined by a plurality of welds 14, respectively, The electric resistance of the entire metal foil portion is smaller than that in the case where the welded portion 14 is joined.

(4) Since the power storage device (secondary battery) includes the electrode body 10 having the electrode sheet bonding structure, the connection structure has the effect.
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the point that two intermediate groups G3 exist and the point that both outermost groups G1, G2 and the intermediate group G3 are formed to be the same are greatly different from those in the first embodiment. . The same parts as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 3A and 3B, the first outermost group G1 and the second outermost group G2 are joined to different intermediate groups G3 by two welds 14, respectively. The two intermediate groups G3 are also joined by the two welds 14. The metal foil portions (convex portions 11a) of both intermediate groups G3 are provided with total removal portions 15 at locations corresponding to the total removal portions 15 of both outermost groups G1, G2 joined by the welded portion 14.

  In the first embodiment, the formation order (welding order) of the welds 14 existing between two adjacent groups is arbitrary, but in this embodiment, the welds 14 between the intermediate groups G3 are formed first. I can't do it. Therefore, as shown in FIG. 3C, after joining the first outermost group G1 and the intermediate group G3 and joining the second outermost group G2 and the intermediate group G3, the intermediate groups G3 Bonding is performed.

The electrode sheet bonding structure of this embodiment has the following effects in addition to the basically same effects as (1) to (3) of the first embodiment.
(5) A plurality of intermediate groups G3 are provided. Therefore, it is possible to easily cope with a case where the number of metal foil portions to be joined is large as compared with the case where one intermediate group is provided.

  (6) Both end portions of the welded portion 14 are exposed to the cutout portions 16 provided in the first outermost group G1 and the second outermost group G2 that are not joined via the welded portion 14. . Therefore, the end portion of the welded portion 14 does not protrude beyond the entire thickness region of the metal foil portions (convex portions 11a, 12a).

The embodiment is not limited to the above, and may be embodied as follows, for example.
○ As shown in FIGS. 4 (a), (b), and (c), a shape that removes a part of the convex portions 11a and 12a of other groups that interferes when joining adjacent groups is cut. You may respond only by the total removal part 15 without providing the notch part 16. FIG.

When providing all removal part 15, as shown in Drawing 4 (b), one total removal part 15 may be provided in the length corresponding to a plurality of welding parts 14.
○ As shown in FIG. 4 (a) or FIG. 4 (c), without forming a plurality of welds 14 each joining adjacent groups of the outermost groups G1, G2 and the intermediate group G3, You may provide one by one.

  ○ The shape for removing the part that hinders welding between the other groups is not limited to the total removal part 15 and the notch part 16, for example, as shown in FIGS. 5 (a) and 5 (b) You may form the hole 18 (through-hole) in the part corresponding to the welding part 14 which welds these groups. The shape of the hole 18 is not limited to a circle, and may be any shape, for example, a polygon.

  ○ The metal foil portions (convex portions 11a, 12a) of the electrode sheets constituting the first outermost group G1 and the second outermost group G2, and the metal foil portions (convex portions 11a, 12a) of the adjacent intermediate group G3 As shown in FIG. 5 (c), only the notch portion 16 is provided without providing the entire removal portion 15 as a shape in which the portion corresponding to the weld portion 14 formed in FIG. ), A notch 16 and a hole 18 may be provided.

  The electrode body 10 is not limited to a laminated type, and for example, as shown in FIG. It may be a wound type formed in the above.

The welded portion 14 is not limited to arc welding, and may be formed by spot welding using ultrasonic welding or laser welding.
The moving body is not limited to a general vehicle provided with a traveling motor, and may be other industrial vehicles such as forklifts, excavator loaders, towing tractors, and the like. Further, the vehicle is not limited to a vehicle that requires a driver, and may be an automatic guided vehicle.

○ The moving body is not limited to a vehicle but may be a ship or a robot.
○ The power storage device is not limited to a secondary battery (unit cell) or a battery pack. For example, a capacitor such as an electric double layer capacitor or a lithium ion capacitor, or a capacitor is electrically connected in series or in parallel by a terminal connecting member. It may be what was done.

  G1 ... 1st outermost group, G2 ... 2nd outermost group, G3 ... Intermediate group, 10 ... Electrode body, 11 ... Positive electrode sheet, 12 ... Negative electrode sheet, 11a, 12a ... Convex part as metal foil part, 14 ... welds, 16 ... notches.

Claims (5)

A power storage device comprising an electrode body joined by spot welding in a state where a plurality of metal foil portions of a positive electrode sheet and a negative electrode sheet as an electrode sheet are laminated,
The metal foil portion of the electrode sheet has a first outermost group and a second outermost group arranged on the outermost sides in the stacking direction, and one or more intermediate groups arranged between both outermost groups. And a plurality of the metal foil portions,
The metal foil portions of two adjacent groups are joined by a welded portion, and the metal foil portions of all the positive electrode sheets and the metal foil portions of all the negative electrode sheets are electrically connected to each other. And
The metal foil part of the electrode sheet constituting at least one of the first outermost group and the second outermost group is a position of the welded part formed in the metal foil part of the adjacent intermediate group. The metal foil portion formed in the stacking direction at the position of the welded portion is formed in the metal foil portion of the intermediate group and the metal of one group adjacent to the intermediate group. A power storage device including only a foil portion.   The power storage device according to claim 1, wherein a plurality of intermediate groups are provided.   Both end portions of the welded portion in the stacking direction are the notch portions provided in the first outermost group, the second outermost group, or the intermediate group that are not joined via the welded portion. The power storage device according to claim 2, wherein the power storage device is exposed in the through hole.   The power storage device according to claim 1, wherein the weld is formed by arc welding.   The secondary battery which has the structure of the electrical storage apparatus as described in any one of Claims 1-4.