JP6476726B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device.

  In recent years, lithium ion secondary batteries have been adopted not only as power sources for electronic devices but also as power sources for hybrid vehicles and electric vehicles. Usually, an electrode assembly as a power generation element is accommodated in a battery case of a lithium ion secondary battery. The electrode assembly includes a positive electrode obtained by coating a metal foil with a positive electrode active material, and a negative electrode active material on the metal foil. And a separator interposed between the positive electrode and the negative electrode. As an electrode assembly, for example, there are a wound electrode assembly and a stacked electrode assembly. The wound electrode body is formed by winding an electrode sheet with a separator interposed between a long positive electrode and a negative electrode. On the other hand, a stacked electrode assembly has a structure in which a large number of positive electrodes, negative electrodes, and separators are alternately stacked.

  As a conventional power storage device, for example, a power storage device disclosed in Patent Document 1 is known. The power storage device disclosed in Patent Document 1 includes a layered electrode assembly in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked while maintaining an insulating state, and a battery case that houses the electrode assembly; A positive electrode terminal for taking out electricity and a negative electrode terminal for taking out electricity from the negative electrode are provided. The positive electrode has a positive electrode active material layer obtained by coating a positive electrode metal foil with a positive electrode active material, and a positive electrode tab made of a positive electrode metal foil not coated with a positive electrode active material. The positive electrode tab is formed so as to protrude from the end of the positive electrode. The negative electrode has a negative electrode active material layer obtained by coating a negative electrode metal foil with a negative electrode active material, and a negative electrode tab made of a negative electrode metal foil not coated with the negative electrode active material. The negative electrode tab is formed so as to protrude from the end of the negative electrode. A positive electrode conductive member that electrically connects the positive electrode tab with the positive electrode terminal is provided, and a negative electrode conductive member that electrically connects the negative electrode tab with the negative electrode terminal. The positive electrode terminal and the negative electrode terminal protrude from the inside of the battery case to the outside.

  When the width direction of the region where the positive electrode active material layer and the negative electrode active material layer overlap in the electrode assembly is a direction orthogonal to the direction in which the positive electrode tab and the negative electrode tab protrude, the positive electrode terminal is the end in the width direction of the positive electrode tab. On the side. Moreover, the negative electrode terminal is provided in the edge part side of the width direction rather than the negative electrode tab similarly to a positive electrode terminal.

JP 2014-107146 A

  By the way, the power storage device disclosed in Patent Document 1 may have a plurality of power storage devices arranged in a row, and a battery module may be configured by connecting power storage devices adjacent to each other with a bus bar at a positive electrode terminal and a negative electrode terminal. However, in this case, when the power storage devices in the battery module are inclined with respect to each other in the width direction, the positions of the tips of the positive electrode terminal and the negative electrode terminal are shifted from each other for each power storage device. There is a problem that as the position where the positive electrode terminal and the negative electrode terminal are provided is closer to the end portion in the width direction of the battery case, the positional deviation between the tips of the positive electrode terminal and the negative electrode terminal during tilting increases. If the position of the tip of the positive electrode terminal and the negative electrode terminal during tilting is large, problems such as failure to connect a plurality of power storage devices using a bus bar and uncertain connection state of the power storage devices occur.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide the tips of the positive electrode terminal and the negative electrode terminal even when the plurality of power storage devices in the battery module are assembled in a state where they are inclined with respect to the width direction. It is in providing the electrical storage apparatus which can suppress position shift of this.

In order to solve the above problems, the present invention includes a battery case including a layered electrode assembly in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked while maintaining an insulating state, and housing the electrode assembly; A positive electrode terminal that takes out electricity from the positive electrode; and a negative electrode terminal that takes out electricity from the negative electrode. A positive electrode tab made of the positive electrode metal foil not coated, the positive electrode tab is provided so as to protrude from an end of the positive electrode, and the negative electrode has a negative electrode active material applied to the negative electrode metal foil. A negative electrode active material layer coated and a negative electrode tab made of the negative electrode metal foil not coated with the negative electrode active material, and the negative electrode tab is provided so as to protrude from an end of the negative electrode. The positive electrode terminal and the positive electrode tab are connected to each other. In a power storage device that includes a positive electrode connecting portion that connects to the negative electrode terminal and the negative electrode tab, the width direction is defined as a direction connecting the tip of the positive electrode terminal and the tip of the negative electrode terminal. The positive electrode terminal is provided closer to the center of the electrode assembly in the width direction than the positive electrode tab, and the negative electrode terminal is closer to the center of the electrode assembly in the width direction than the negative electrode tab. The positive electrode tab is spaced from one end of the electrode assembly in the width direction, and is provided between the center of the electrode assembly and one end of the electrode assembly in the width direction, negative electrode tabs, especially that provided between the other end of the spaced from the other end of the electrode assembly, and the center and the electrode assembly of the electrode assembly in the width direction in the width direction To.

  In the present invention, in the electrode assembly, the direction connecting the tip of the positive electrode terminal and the tip of the negative electrode terminal is defined as the width direction. The positive electrode terminal is provided at a position closer to the center of the electrode assembly in the width direction than the positive electrode tab, and the negative electrode terminal is provided at a position closer to the center of the electrode assembly in the width direction than the negative electrode tab. For this reason, the distance between the positive electrode terminal and the negative electrode terminal in the electrode assembly can be made as small as possible without being blocked by the positive electrode tab and the negative electrode tab. Therefore, even if the plurality of power storage devices in the battery module are assembled with each other in the width direction, particularly when the lines connecting the positive electrode terminal and the negative electrode terminal of the adjacent power storage devices are inclined with respect to each other, the positions of the tips of the positive electrode terminal and the negative electrode terminal are shifted. Can be suppressed. The smaller the distance between the positive electrode terminal and the negative electrode terminal in the electrode assembly, the smaller the misalignment between the positive electrode terminal and the tip of the negative electrode terminal.

In the above power storage device, when the center of the electrode assembly in the width direction is defined as a virtual reference line extending along the protruding direction, the positive terminal and the negative terminal are centered on the virtual reference line. It is good also as a structure provided so that it may become line symmetrical.
In this case, the positive electrode terminal and the negative electrode terminal are line symmetrical with respect to the virtual reference line, so that it is convenient in terms of production technology, for example, it is only necessary to prepare a battery case that does not need to consider the orientation. Manufacturing cost can be suppressed.

In the above power storage device, the positive electrode terminal is non-overlapping with the positive electrode tab in the projecting direction and is adjacent to the positive electrode tab in the width direction, and the negative electrode terminal is the negative electrode in the projecting direction. It is good also as a structure which is adjacent to the said negative electrode tab in the said width direction while being non-overlapping with a tab.
In this case, since the positive electrode tab and the negative electrode tab in the power storage device are non-overlapping in the protruding direction and adjacent in the width direction, the space in the protruding direction can be set small. Moreover, the electrical resistance from the positive electrode tab to the positive electrode terminal and the electrical resistance from the negative electrode tab to the negative electrode terminal can be suppressed.
In the power storage device, in the width direction, the center of the positive electrode terminal is located closer to the center of the electrode assembly than the center from the center of the electrode assembly to one end of the electrode assembly, and the width In the direction, the center of the negative electrode terminal may be located closer to the center of the electrode assembly than the center from the center of the electrode assembly to the other end of the electrode assembly.

  According to the present invention, it is possible to provide a power storage device that can suppress the displacement of the tips of the positive electrode terminal and the negative electrode terminal even when the plurality of power storage devices in the battery module are assembled in a state of being inclined with respect to each other in the width direction. Can do.

1 is an exploded perspective view of a secondary battery according to a first embodiment of the present invention. It is a longitudinal cross-sectional view of the secondary battery which concerns on the 1st Embodiment of this invention. It is a disassembled perspective view of a part of electrode assembly. It is a perspective view of the battery module provided with two or more secondary batteries which concern on 1st Embodiment. (A) is explanatory drawing which shows the state which the secondary battery which concerns on 1st Embodiment mutually adjoins, and is mutually inclined in the width direction, (b) is the conventional secondary as a comparative example It is explanatory drawing which shows the state which has mutually inclined the battery in the state which is a mutually adjacent state. It is a longitudinal cross-sectional view of the secondary battery which concerns on the 1st Embodiment of this invention.

(First embodiment)
The power storage device according to the first embodiment will be described below with reference to the drawings.
In the present embodiment, a secondary battery as a power storage device is illustrated, and the secondary battery of the present embodiment is specifically a lithium ion secondary battery.

  As shown in FIGS. 1 and 2, the secondary battery 10 of the present embodiment is a rectangular secondary battery. An electrode assembly 20 is accommodated in the battery case 11 of the secondary battery 10. The battery case 11 has a bottomed cylindrical case body 12 and a rectangular flat lid 14 that closes the opening 13 of the case body 12. The case body 12 and the lid body 14 are made of a metal material (for example, aluminum). As shown in FIG. 2, an insulating sheet 15 is attached to the inner surface of the case body 12 as an insulating member for insulation from the electrode assembly 20 accommodated in the battery case 11. In addition, an insulating sheet 16 as an insulating member is attached to the inner side surface of the lid body 14 to insulate the electrode assembly 20 housed in the battery case 11. A pair of through holes 17 are formed in the lid body 14. Further, as shown in FIG. 1, the lid 14 is provided with a safety valve 18. The safety valve 18 is opened when the pressure in the battery case 11 reaches a predetermined pressure. It has a function of releasing gas to the outside.

The electrode assembly 20 is a power generation element that generates a battery function (such as charging / discharging).
As shown in FIG. 3, the electrode assembly 20 includes a sheet-like positive electrode 21 and a sheet-like negative electrode 22. The positive electrode 21 has a rectangular positive electrode main body 23 and a strip-shaped positive electrode tab 24 formed at the end of the positive electrode main body 23. The positive electrode body 23 includes a positive electrode metal foil 25 and a positive electrode active material layer 26 formed of a positive electrode active material coated on both surfaces of the positive electrode metal foil 25. The positive electrode tab 24 is provided so as to protrude from the end of the positive electrode 21. The end where the positive electrode tab 24 is provided is the long side of the positive electrode main body 23, and is the long side facing the lid body 14 when the electrode assembly 20 is accommodated in the battery case 11. The positive electrode tab 24 is formed of a positive electrode metal foil 25, and the positive electrode tab 24 is not coated with a positive electrode active material. In addition, the positive electrode metal foil 25 of this embodiment is an aluminum foil.

  The negative electrode 22 has a rectangular negative electrode main body 27 and a strip-shaped negative electrode tab 28 formed at the end of the negative electrode main body 27. The negative electrode main body 27 has a negative electrode metal foil 29 and a negative electrode active material layer 30 formed of a negative electrode active material coated on both surfaces of the negative electrode metal foil 29. The negative electrode tab 28 is provided so as to protrude from the end of the negative electrode 22. The end where the negative electrode tab 28 is provided is the long side of the negative electrode main body 27, and is the long side facing the lid body 14 when the electrode assembly 20 is housed in the battery case 11. The negative electrode tab 28 is formed of a negative electrode metal foil 29, and the negative electrode tab 28 is not coated with a negative electrode active material. In addition, the negative electrode metal foil 29 of this embodiment is a copper foil.

  In the present embodiment, the width direction of the region where the positive electrode active material layer 26 and the negative electrode active material layer 30 overlap in the electrode assembly 20 is defined as the direction orthogonal to the direction in which the positive electrode tab 24 and the negative electrode tab 28 protrude. The width direction of the region where the positive electrode active material layer 26 and the negative electrode active material layer 30 overlap in the electrode assembly 20 corresponds to the width direction of the electrode assembly 20 (the left-right direction shown in FIG. 1). The electrode assembly 20 has a separator 31 that insulates between the positive electrode 21 and the negative electrode 22, and has a layered structure in which the plurality of positive electrodes 21 and the plurality of negative electrodes 22 are alternately stacked while maintaining an insulating state.

  The positive electrode tabs 24 are arranged in a line along the stacking direction of the electrode assemblies 20. Similarly to the positive electrode tab 24, the negative electrode tabs 28 are arranged in a row along the stacking direction. In the electrode assembly 20, the negative electrode tabs 28 and the positive electrode tabs 24 are disposed at positions separated from the positive electrode tabs 24 in the width direction so that the negative electrode tabs 28 and the positive electrode tabs 24 do not overlap each other. In the present embodiment, the positive electrode tabs 24 are set to the same size, and the negative electrode tabs 28 are also set to the same size. The positive electrode tabs 24 are gathered at one end of the electrode assembly 20 in the stacking direction to form a positive electrode tab group 32. Similarly to the positive electrode tab 24, each of the negative electrode tabs 28 is collected at an end portion on one side of the center of the electrode assembly 20 in the stacking direction to form a negative electrode tab group 33. In the present embodiment, one side from the center in the stacking direction of the electrode assembly 20 is one side, and the other side from the center in the stacking direction is the other side.

  A positive electrode current collector plate 34 is bonded to the positive electrode tab group 32, and a negative electrode current collector plate 35 is bonded to the negative electrode tab group 33. The positive electrode current collector plate 34 and the negative electrode current collector plate 35 are rectangular flat plates as shown in FIG. The length in the short direction of the positive electrode current collector plate 34 and the negative electrode current collector plate 35 is set to be smaller than the thickness of the electrode assembly 20 in the stacking direction. As shown in FIG. 2, the length in the longitudinal direction of the positive electrode current collector plate 34 is set to a length that does not interfere with other members when the positive electrode tab group 32 is joined to the positive electrode current collector plate 34. Further, the length in the longitudinal direction of the negative electrode current collector plate 35 is set to a length that does not interfere with other members when the negative electrode tab group 33 is joined to the negative electrode current collector plate 35, similarly to the positive electrode current collector plate 34. Has been. In the present embodiment, in a state where the positive electrode tab group 32 is bonded to the positive electrode current collector plate 34, the positive electrode current collector plate 34 is in a direction (width direction) orthogonal to the stacking direction of the electrode assembly 20 and the negative electrode tab 28. Protrusively toward. In a state where the negative electrode tab group 33 is bonded to the negative electrode current collector plate 35, the negative electrode current collector plate 35 is in a direction (width direction) orthogonal to the stacking direction of the electrode assembly 20 and toward the positive electrode tab 24. Protruding. The thickness of the positive electrode current collector plate 34 and the negative electrode current collector plate 35 is set to a thickness (about 1.5 mm) that enables the electrode assembly 20 to collect current as necessary and sufficiently.

  As shown in FIG. 2, the positive electrode current collector plate 34 is provided with a positive electrode terminal 37 that is electrically connected via an overcurrent protection circuit 36. Further, the negative electrode current collector plate 35 is provided with a negative electrode terminal 38 that is electrically connected via an overcurrent protection circuit 36. Accordingly, the positive electrode current collector plate 34 corresponds to a positive electrode connection portion that electrically connects the positive electrode terminal 37 and the positive electrode tab 24, and the negative electrode current collector plate 35 electrically connects the negative electrode terminal 38 and the negative electrode tab 28. Corresponds to the negative electrode connection. In a state where the electrode assembly 20 is accommodated in the battery case 11, the positive electrode terminal 37 and the negative electrode terminal 38 are exposed to the outside of the battery case 11 through the pair of through holes 17 of the lid body 14. A cylindrical insulating ring 39 made of resin for insulating the positive terminal 37 and the negative terminal 38 from the lid body 14 is attached to the positive terminal 37 and the negative terminal 38, respectively (see FIGS. 1 and 2). . The positive electrode terminal 37 extends from the inside of the battery case 11 to the outside through the through hole 17. The positive terminal 37 and the negative terminal 38 pass through the through hole 17 and protrude from the inside of the battery case 11 to the outside. Therefore, the base end on the connection side of the positive electrode terminal 37 and the negative electrode terminal 38 is located inside the battery case 11, and the distal ends of the positive electrode terminal 37 and the negative electrode terminal 38 are located outside the battery case 11. Therefore, the direction connecting the tip of the positive electrode terminal 37 and the tip of the negative electrode terminal 38 coincides with the width direction of the region where the positive electrode active material layer 26 and the negative electrode active material layer 30 overlap in the electrode assembly 20.

  In the present embodiment, the positive electrode terminal 37 is provided at a position closer to the center of the electrode assembly 20 in the width direction than the positive electrode tab 24, and the negative electrode terminal 38 is the center of the electrode assembly 20 in the width direction than the negative electrode tab 28. It is provided in the position near. Therefore, the distance between the positive electrode terminal 37 and the negative electrode terminal 38 is smaller than the conventional one without being blocked by the positive electrode tab 24 and the negative electrode tab 28. In the present embodiment, as shown in FIG. 2, when the virtual reference line P extending along the direction protruding from the center in the width direction of the electrode assembly 20 is defined, the positive terminal 37 and the negative terminal 38 are connected to the virtual reference line. It arrange | positions so that it may become line symmetrical about P.

  By the way, in this embodiment, as shown in FIG. 4, a plurality of secondary batteries 10 are arranged in a row, and the positive terminal 37 and the negative terminal 38 of the secondary battery 10 are separated from each other by the bus bar 41. Are connected in series to form the battery module 40. When the secondary batteries 10 of the battery module 40 are inclined with respect to each other in the width direction, the positions of the tips of the positive electrode terminal 37 and the negative electrode terminal 38 are displaced from each other for each secondary battery 10. However, in the present embodiment, the positive electrode terminal 37 and the negative electrode terminal 38 are arranged close to each other in the width direction of the electrode assembly 20, thereby suppressing the positional deviation of the tips of the positive electrode terminal 37 and the negative electrode terminal 38. The smaller the distance between the positive electrode terminal 37 and the negative electrode terminal 38 in the electrode assembly 20, the smaller the positional deviation between the tips of the positive electrode terminal 37 and the negative electrode terminal 38. In addition, the distance between the positive electrode terminal 37 and the negative electrode terminal 38 in the width direction of the electrode assembly 20 may be a range that does not cause a short circuit, and may be, for example, a distance of about several millimeters.

  FIG. 5A is an explanatory diagram showing a state in which the secondary batteries 10 according to the present embodiment are adjacent to each other and inclined in the width direction. FIG. 5B is an explanatory diagram showing a state in which conventional secondary batteries are adjacent to each other and inclined in the width direction as a comparative example. In FIG. 5A, in order to easily distinguish one secondary battery 10 from the other secondary battery 10, for convenience, one secondary battery 10 is shown by a solid line, and the other secondary battery 10 is Indicated by a two-dot chain line. Further, FIG. 5B is also illustrated in the same manner as FIG. The secondary battery 10 of this embodiment shown in FIG. 5A is compared with the comparative example shown in FIG. 5B, the positive terminal 37 of one secondary battery 10 and the negative terminal of the other secondary battery 10. The positional deviation H from the tip of 38 is small. That is, as the distance between the positive electrode terminal 37 and the negative electrode terminal 38 in the electrode assembly 20 becomes smaller, the positional deviation H at the tips of the positive electrode terminal 37 and the negative electrode terminal 38 becomes smaller. Further, in the secondary battery 10 of the present embodiment, compared to the comparative example shown in FIG. 5B, the negative terminal 38 of one secondary battery 10 and the tip of the positive terminal 37 of the other secondary battery 10. Small misalignment. Therefore, even if the plurality of secondary batteries 10 in the battery module 40 are assembled to be inclined with respect to each other in the width direction, the positional deviation H at the tips of the positive terminal 37 and the negative terminal 38 can be suppressed.

The secondary battery 10 of this embodiment has the following effects.
(1) In the electrode assembly 20, the direction connecting the tip of the positive electrode terminal 37 and the tip of the negative electrode terminal 38 is defined as the width direction. The positive electrode terminal 37 is provided at a position closer to the center of the electrode assembly 20 in the width direction than the positive electrode tab 24, and the negative electrode terminal 38 is provided at a position closer to the center of the electrode assembly 20 in the width direction than the negative electrode tab 28. It has been. For this reason, the distance between the positive electrode terminal 37 and the negative electrode terminal 38 in the electrode assembly 20 can be made as small as possible without being blocked by the positive electrode tab 24 and the negative electrode tab 28. Therefore, even if the plurality of secondary batteries 10 in the battery module 40 are inclined with respect to each other in the width direction, and particularly when the lines connecting the positive electrode terminal 37 and the negative electrode terminal 38 of the adjacent secondary battery 10 are inclined with respect to each other, the positive electrode terminal 37 is assembled. And the positional deviation H of the tip of the negative electrode terminal 38 can be suppressed. The smaller the distance between the positive electrode terminal 37 and the negative electrode terminal 38 in the electrode assembly 20, the smaller the positional deviation between the tips of the positive electrode terminal 37 and the negative electrode terminal 38.

(2) When the virtual reference line P extending along the protruding direction is defined as the center in the width direction of the electrode assembly 20, the positive terminal 37 and the negative terminal 38 are symmetrical with respect to the virtual reference line P. Is provided. For this reason, it is advantageous in terms of production technology, for example, it is only necessary to prepare the battery case 11 that does not need to consider the orientation, and thus the manufacturing cost of the secondary battery 10 can be suppressed.

(3) The positive electrode terminal 37 does not overlap with the positive electrode tab 24 in the protruding direction, and the negative electrode terminal 38 does not overlap with the negative electrode tab 28 in the protruding direction. For this reason, the space (space between the positive electrode tab 24 and the negative electrode tab 28 and the cover body 14) in the protruding direction in the battery case 11 can be set small. That is, generation of useless space in the battery case 11 can be suppressed.

(Second Embodiment)
Next, a power storage device according to the second embodiment will be described.
This embodiment is different from the first embodiment in that the positive electrode terminal (negative electrode terminal) is adjacent to the positive electrode tab (negative electrode tab) in the width direction of the electrode assembly. In the present embodiment, the description of the first embodiment is used for the same configuration as the first embodiment, and the reference numerals are used in common.

In the secondary battery 50 shown in FIG. 6, the positive electrode terminal 37 is not overlapped with the positive electrode tab 24 in the protruding direction and is adjacent to the positive electrode tab 24 in the width direction of the electrode assembly 20. The negative electrode terminal 38 is not overlapped with the negative electrode tab 28 in the protruding direction and is adjacent to the negative electrode tab 28 in the width direction of the electrode assembly 20. Therefore, there is no gap between the positive electrode terminal 37 and the positive electrode tab 24 and between the negative electrode terminal 38 and the negative electrode tab 28 in the width direction of the electrode assembly 20. Therefore, the positive electrode current collector plate 34 and the negative electrode current collector plate 35 have a smaller dimension in the width direction as compared with the first embodiment.
According to the present embodiment, the same effects as those of the first embodiment can be obtained, the dimensions in the width direction of the positive electrode current collector plate 34 and the negative electrode current collector plate 35 can be reduced, and the positive electrode tab 24 to the positive electrode terminal 37. And the electrical resistance from the negative electrode tab 28 to the negative electrode terminal 38 can be suppressed.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the invention. For example, the following modifications may be made.

In the above embodiment, the safety valve is provided between the positive electrode terminal and the negative electrode terminal in the width direction in the lid, but the position of the safety valve is not limited to between the positive electrode terminal and the negative electrode terminal. For example, the lid may be provided between the positive electrode terminal and the case body in the width direction. In this case, since the safety valve is not provided between the positive electrode terminal and the negative electrode terminal in the width direction in the lid, the positive electrode terminal and the negative electrode terminal can be brought closer to each other. As a result, even when the plurality of secondary batteries in the battery module are assembled with each other inclined in the width direction, the positional deviation between the positive electrode terminal and the tip of the negative electrode terminal can be further reduced.
In the above embodiment, the positive electrode terminal and the negative electrode terminal are provided so as to be symmetric with respect to the virtual reference line, but this is not restrictive. The positive electrode terminal and the negative electrode terminal may be provided so as not to be symmetric about the virtual reference line. Even in this case, the distance between the positive electrode terminal and the negative electrode terminal in the electrode assembly can be made as small as possible without being blocked by the positive electrode tab and the negative electrode tab.
In the above embodiment, the lithium ion secondary battery is exemplified as the power storage device. However, the power storage device is not limited to the lithium ion secondary battery, and may be, for example, another secondary battery such as nickel hydride. Any secondary battery having a type electrode assembly may be used.

Next, the technical ideas that can be grasped from the above embodiments and other examples will be described below.
(A) A battery module comprising a plurality of the power storage devices arranged in a row and the power storage devices adjacent to each other being connected by a bus bar.
(B) In the battery module, the power storage devices adjacent to each other are battery modules in which a positive electrode terminal and a negative electrode terminal are arranged close to the width direction of the electrode assembly and connected in series.

10, 50 Secondary battery 11 Battery case 12 Case body 14 Cover body 17 Through hole 18 Safety valve 20 Electrode assembly 21 Positive electrode 22 Negative electrode 23 Positive electrode body 24 Positive electrode tab 25 Positive electrode metal foil 26 Positive electrode active material layer 27 Negative electrode body 28 Negative electrode tab 29 Negative electrode metal foil 30 Negative electrode active material layer 31 Separator 32 Positive electrode tab group 33 Negative electrode tab group 34 Positive electrode current collector plate 35 Negative electrode current collector plate 37 Positive electrode terminal 38 Negative electrode terminal 40 Battery module P Virtual reference line

Claims (4)

A layered electrode assembly in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked while maintaining an insulating state,
A battery case for housing the electrode assembly;
A positive electrode terminal for taking out electricity from the positive electrode;
A negative electrode terminal for taking out electricity from the negative electrode,
The positive electrode has a positive electrode active material layer obtained by applying a positive electrode active material to a positive electrode metal foil, and a positive electrode tab made of the positive electrode metal foil not coated with the positive electrode active material,
The positive electrode tab is provided so as to protrude from an end of the positive electrode,
The negative electrode has a negative electrode active material layer coated with a negative electrode active material on a negative electrode metal foil, and a negative electrode tab made of the negative electrode metal foil not coated with the negative electrode active material,
The negative electrode tab is provided to protrude from an end of the negative electrode,
A positive electrode connection portion connecting the positive electrode terminal and the positive electrode tab;
In a power storage device including a negative electrode connecting portion that connects the negative electrode terminal and the negative electrode tab,
When the direction connecting the tip of the positive terminal and the tip of the negative terminal is defined as the width direction,
The positive electrode terminal is provided at a position closer to the center of the electrode assembly in the width direction than the positive electrode tab,
The negative electrode terminal is provided closer to the center of the electrode assembly in the width direction than the negative electrode tab ,
The positive electrode tab is spaced from one end of the electrode assembly in the width direction, and is provided between a center of the electrode assembly in the width direction and one end of the electrode assembly,
The negative electrode tab is separated from the other end of the electrode assembly in the width direction, and is provided between the center of the electrode assembly and the other end of the electrode assembly in the width direction. A power storage device.   When the center of the electrode assembly in the width direction is defined as a virtual reference line extending along the protruding direction, the positive terminal and the negative terminal are provided so as to be symmetrical with respect to the virtual reference line. The power storage device according to claim 1, wherein the power storage device is provided. The positive electrode terminal is non-overlapping with the positive electrode tab in the protruding direction and is adjacent to the positive electrode tab in the width direction;
The power storage device according to claim 1, wherein the negative electrode terminal is non-overlapping with the negative electrode tab in the protruding direction and is adjacent to the negative electrode tab in the width direction. In the width direction, the center of the positive electrode terminal is located closer to the center of the electrode assembly than the center from the center of the electrode assembly to one end of the electrode assembly,
The center of the negative electrode terminal is located closer to the center of the electrode assembly than the center from the center of the electrode assembly to the other end of the electrode assembly in the width direction. The electrical storage apparatus as described in any one of -3.

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