JP2021022482A - Power storage device - Google Patents

Abstract

To provide a power storage device capable of suppressing spread of an electrode assembly in a lamination direction due to bending of an electrode.SOLUTION: A secondary battery includes an insulating cover 34 arranged in a case 11. The insulating cover 34 has a first tab insulator 52a which is arranged between a tab group 15 and a case main body 13 on a first end side in a lamination direction and insulates the tab group 15 and the case main body 13. A first end surface 12c and a second end surface 12d of the electrode assembly 12 have a first lamination region A1 on which a first lamination portion 121 is projected, the first lamination portion 121 containing positive electrode active material layers 24 and negative electrode active material layers 28 which are laminated alternately, and a second lamination region A2 on which a second lamination portion 122 is projected, the second lamination portion 122 containing portions of negative electrode active material layers 28 which protrude beyond tab-side edge portions 25a of positive active material layers 25 and are laminated. The insulating cover 34 has a first intervening portion 52b continuous with the first tab insulator 52a. The first intervening portion 52b intervenes between the second lamination region A2 of the first end surface 12c of the electrode assembly 12 and the case main body 13.SELECTED DRAWING: Figure 4

Description

The present invention relates to a power storage device including an electrode assembly in which a first electrode, a first electrode, and a second electrode having a different size are laminated.

Vehicles such as EVs (Electric Vehicles) and PHVs (Plug in Hybrids) are equipped with a secondary battery as a power storage device that stores the power supplied to the traveling motor. The secondary battery disclosed in Patent Document 1 has a first electrode having a first active material layer on at least one side of a sheet-shaped first current collector and a second active material on at least one side of a sheet-shaped second current collector. It includes an electrode assembly in which a second electrode having a layer is laminated, and a case for accommodating the electrode assembly. The electrode assembly includes a first tab group in which a first tab having a shape protruding from one side of the first electrode is laminated, and a second tab group in which a second tab having a shape protruding from one side of the second electrode is laminated. Has. The size of the second active material layer is set larger than the size of the first active material layer. Therefore, in the electrode assembly, the first laminated portion in which the first active material layer and the second active material layer are alternately laminated, and the portion of the second active material layer that protrudes from the first active material layer are laminated. It also has a second laminated portion. The secondary battery is arranged between the electrode assembly and the case, and includes an insulating sheet that insulates the electrode assembly and the case.

Further, the secondary battery disclosed in Patent Document 2 is provided with an insulating cover inside the case. The insulating cover has a first tab insulating portion arranged between the tab group and the case on the first end side in the stacking direction, and a second tab insulating portion arranged between the tab group and the case on the second end side in the stacking direction. It has a 2-tab insulation part. The first tab insulation portion and the second tab insulation portion insulate the tab group from the case.

Japanese Unexamined Patent Publication No. 2014-38736 JP-A-2015-130253

By the way, in the second laminated portion, a gap is formed between the second electrodes because the first active material layer is not laminated. For this reason, the second electrode located on the end side in the stacking direction may bend so as to approach the case, and the electrode assembly may expand in the stacking direction. In this case, for example, the distance between the first electrode and the second electrode becomes longer than the desired distance, which causes the precipitation of lithium, or unintended stress is generated in the second electrode, so that the active material layer is formed. There is a risk of peeling.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a power storage device capable of suppressing the spread of electrode assemblies in the stacking direction due to electrode bending.

The power storage device for solving the above problems includes a first electrode having a first active material layer on at least one side of the sheet-shaped first current collector, and a second electrode on at least one side of the sheet-shaped second current collector. An electrode set having a tab group in which a second electrode having an active material layer is laminated, and tabs having a shape protruding from one side of the first current collector and the second current collector are laminated with the same polarity. A solid, a case for accommodating the electrode assembly, and an insulating cover arranged in the case are provided, and the insulating cover is in a stacking direction in which the first electrode and the second electrode are laminated. A first tab insulating portion that is arranged between the tab group and the case on the first end side of the above and that insulates the tab group and the case, and a side opposite to the first end side in the stacking direction. It is arranged between the tab group and the case on the second end side, has at least one of the second tab insulating portions that insulate the tab group and the case, and has one side of the first current collector and the case. When the direction along one side of the second current collector is the first direction and the direction orthogonal to both the first direction and the stacking direction is the second direction, the second active material layer in the second direction The dimensions are larger than the dimensions of the first active material layer in the second direction, and in the electrode assembly, the first active material layer and the second active material layer alternate on the end face in the stacking direction. The first laminated region on which the first laminated portion to be laminated is projected, and the first active material layer in the second active material layer while being located on the tab group side of the first laminated portion in the second direction. A power storage device having a second laminated region on which a second laminated portion on which a portion protruding from the edge portion of the above is laminated is projected, and the insulating cover is continuous with the first tab insulating portion and the first tab. At least one of the first intervening portion interposed between the two laminated regions and the case and the second interposing portion that is continuous with the second tab insulating portion and is interposed between the second laminated region and the case. The gist is to have.

According to this, the intervening portion suppresses the bending of the second electrode located on the end side in the stacking direction toward the case side. Therefore, it is possible to suppress the spread of the electrode assembly in the stacking direction due to the bending of the electrodes.

The power storage device for solving the above problems includes a first electrode having a first active material layer on at least one side of the sheet-shaped first current collector, and a second electrode on at least one side of the sheet-shaped second current collector. An electrode set having a tab group in which a second electrode having an active material layer is laminated and tabs having a shape protruding from one side of the first current collector and the second current collector are laminated with the same polarity. A solid body, a case for accommodating the electrode assembly, and a first end surface and the case of the electrode assembly located on the first end side in the stacking direction in which the first electrode and the second electrode are laminated. A first insulating sheet portion that is arranged between the electrode assembly and the case to insulate the case, and the electrode assembly that is located on the second end side opposite to the first end side in the stacking direction. A second insulating sheet portion, which is arranged between the second end surface of the above and the case and insulates the electrode assembly and the case, is provided, and one side of the first current collector and the second current collector are provided. When the direction along one side is the first direction and the direction orthogonal to both the first direction and the stacking direction is the second direction, the dimensions of the second active material layer in the second direction are the first. The first laminated portion is larger than the size of the first active material layer in two directions, and the first end surface and the second end surface are laminated with the first active material layer and the second active material layer alternately. Is located on the tab group side of the first laminated portion in the second direction and protrudes from the edge of the first active material layer in the second active material layer. A power storage device having a second laminated region on which a second laminated portion is projected, and at least one of the first insulating sheet portion and the second insulating sheet portion is along the inner surface of the case. The gist is that it has a bent portion that is arranged between the surface portion, the second laminated region, and the case, and is bent so as to bulge toward the electrode assembly side from the creeping portion.

According to this, the bent portion prevents the second electrode located on the end side in the stacking direction from bending toward the case side. Therefore, it is possible to suppress the spread of the electrode assembly in the stacking direction due to the bending of the electrodes.

Further, with respect to the power storage device, the tab group includes a foil collecting portion in which the portions collected on the first end side in the stacking direction of the tab are laminated, and the foil collecting portion is bent to form the stacking direction. The insulating cover has an extending portion extending toward the second end side of the above, and the insulating cover projects toward the second end side in the stacking direction and supports the foil collecting portion from the electrode assembly side. It is preferable to have a portion.

When there is no protruding portion, the portion of the tab side end surface of the electrode assembly located on the first end side in the stacking direction is crushed by the foil collecting portion, so that the second electrode located on the first end side in the stacking direction is formed. May bend. On the other hand, since the foil collecting portion is supported by the protruding portion, the portion of the tab-side end surface of the electrode assembly located on the first end side in the stacking direction is suppressed from being crushed by the foil collecting portion. Therefore, the bending of the second electrode located on the first end side in the stacking direction is further suppressed. Therefore, it is possible to further suppress the spread of the electrode assembly in the stacking direction due to the bending of the electrodes.

Further, with respect to the power storage device, the tab group includes a foil collecting portion in which the portions collected on the first end side in the stacking direction of the tab are laminated, and the foil collecting portion is bent to form the stacking direction. It has an extending portion extending toward the second end side of the above, and has a first tab insulating portion arranged between the foil collecting portion and the case on the first end side in the stacking direction. The first tab insulating portion preferably has a protruding portion that projects toward the second end side in the stacking direction and supports the foil collecting portion from the electrode assembly side.

When there is no protruding portion, the portion of the tab side end surface of the electrode assembly located on the first end side in the stacking direction is crushed by the foil collecting portion, so that the second electrode located on the first end side in the stacking direction is formed. May bend. On the other hand, since the foil collecting portion is supported by the protruding portion, the portion of the tab-side end surface of the electrode assembly located on the first end side in the stacking direction is suppressed from being crushed by the foil collecting portion. Therefore, the bending of the second electrode located on the first end side in the stacking direction is further suppressed. Therefore, it is possible to further suppress the spread of the electrode assembly in the stacking direction due to the bending of the electrodes.

Further, the power storage device includes a conductive member arranged between the extension portion and the case and electrically connected to the tab group, and the foil collecting portion is the first of the conductive members. It is preferably located between the end face on the tab insulating portion side and the end face on the tab group side in the first tab insulating portion.

If there is no gap between the end face of the conductive member on the tab side of the first tab insulation portion and the end face of the first tab insulation portion on the tab group side, the foil collecting portion is placed between the conductive member and the tab side end face of the electrode assembly. It is crushed, and the portion of the tab side end surface of the electrode assembly located on the first end side in the stacking direction is crushed by the foil collecting portion. Therefore, the second electrode located on the first end side in the stacking direction tends to bend toward the case side.

On the other hand, since the foil collecting portion is located between the end face on the first tab insulating portion side of the conductive member and the end face on the tab group side in the first tab insulating portion, the foil collecting portion is crushed by the conductive member. It becomes difficult. Therefore, it is suppressed that the portion of the tab side end surface of the electrode assembly located on the first end side in the stacking direction is crushed by the foil collecting portion, and the second electrode located on the first end side in the stacking direction is the case. Bending to the side is more suppressed. Therefore, it is possible to further suppress the spread of the electrode assembly in the stacking direction due to the bending of the electrodes.

Further, with respect to the power storage device, it is preferable that the protruding portion is arranged only in the portion where the tab group is located in the first direction.
When the power storage device is used, the second electrode expands toward the protrusion. At this time, since the protruding portion is arranged only in the portion where the tab group is located in the first direction, the interference between the expanded second electrode and the protruding portion can be minimized.

Further, with respect to the power storage device, it is preferable that the tip surface of the protruding portion is inclined so as to be separated from the first tab insulating portion from the first end side to the second end side in the stacking direction.

When the protruding portion supports the foil collecting portion of the tab group from the electrode assembly side, the foil collecting position of the tab forming the tab group is set to the second end side in the stacking direction with respect to the tip surface of the protruding portion. Therefore, by inclining the tip surface of the protruding portion away from the first tab insulating portion as it goes from the first end side to the second end side in the stacking direction, the tab located on the first end side in the stacking direction. Is easier to direct toward the second end side in the stacking direction than the tip surface of the protruding portion.

According to the present invention, it is possible to suppress the spread of the electrode assembly in the stacking direction due to the bending of the electrodes.

An exploded perspective view of the secondary battery of the first embodiment. An exploded perspective view of the electrode assembly. Top view of the electrode assembly. FIG. 3 is a partial cross-sectional view of the secondary battery of the first embodiment. FIG. 3 is a partial cross-sectional view of the secondary battery of the second embodiment.

(First Embodiment)
Hereinafter, a first embodiment in which the power storage device is embodied in a secondary battery will be described with reference to FIGS. 1 to 4.

As shown in FIG. 1, the secondary battery 10 as a power storage device includes a case 11. The secondary battery 10 includes an electrode assembly 12 housed in a case 11. The case 11 has a rectangular parallelepiped case body 13 and a flat plate-shaped lid 14 that closes the opening 13a of the case body 13. The case body 13 has a rectangular bottom wall 13b, a long side wall 13c erected from a pair of long side edges of the bottom wall 13b, and a short side wall erected from a pair of short side edges of the bottom wall 13b. It has 13d and. In the lid 14, the surface facing the inside of the case 11 is the inner surface 14a, and the surface facing the outside of the case 11 is the outer surface 14b. The case body 13 and the lid 14 constituting the case 11 are both made of metal (for example, stainless steel or aluminum). Further, the secondary battery 10 of the present embodiment is a square battery having a square appearance. Further, the secondary battery 10 of the present embodiment is a lithium ion battery.

As shown in FIG. 2, the electrode assembly 12 includes a positive electrode 21 as a plurality of first electrodes, a negative electrode 22 as a plurality of second electrodes, and a plurality of separators 23. The positive electrode 21, the negative electrode 22, and the separator 23 are each in the form of a sheet. The electrode assembly 12 has a layered structure in which a separator 23 is interposed between the positive electrode 21 and the negative electrode 22 and is laminated in a state of being insulated from each other.

The positive electrode electrode 21 has a positive electrode current collector 24 as a first current collector and a positive electrode active material layer 25 as a first active material layer existing on both sides of the positive electrode current collector 24. The positive electrode current collector 24 has a rectangular shape. The positive electrode current collector 24 has a first edge portion 24a as one side extending in the longitudinal direction, and a second edge portion 24b extending in the longitudinal direction and located on the opposite side of the first edge portion 24a in the lateral direction. .. The positive electrode 21 has an uncoated portion 24e along the first edge portion 24a. The uncoated portion 24e is a portion where the positive electrode active material layer 25 does not exist and the positive electrode current collector 24 is exposed. The positive electrode active material layer 25 has a tab side edge portion 25a at an edge portion along the first edge portion 24a. Further, the positive electrode electrode 21 has a tab 26 protruding from the first edge portion 24a. The tab 26 does not have the positive electrode active material layer 25 and is composed of the positive electrode current collector 24 itself. The positive electrode 21 has a third edge portion 24c extending in the lateral direction and a fourth edge portion 24d extending in the lateral direction and located on the opposite side of the third edge portion 24c in the longitudinal direction.

The negative electrode electrode 22 has a negative electrode current collector 27 as a second current collector and a negative electrode active material layer 28 as a second active material layer existing on both sides of the negative electrode current collector 27. The negative electrode current collector 27 has a rectangular shape. The negative electrode current collector 27 has a first edge portion 27a as one side extending in the longitudinal direction, and a second edge portion 27b extending in the longitudinal direction and located on the opposite side of the first edge portion 27a in the lateral direction. .. The negative electrode 22 has a tab 26 protruding from the first edge 27a. The tab 26 does not have the negative electrode active material layer 28, and is composed of the negative electrode current collector 27 itself. The negative electrode current collector 27 has a third edge portion 27c extending in the lateral direction and a fourth edge portion 27d extending in the lateral direction and located on the opposite side of the third edge portion 27c in the longitudinal direction.

The longitudinal dimension of the negative electrode current collector 27 is larger than the longitudinal dimension of the positive electrode current collector 24, and the lateral dimension of the negative electrode current collector 27 is the lateral dimension of the positive electrode current collector 24. Greater than. Further, the longitudinal dimension of the negative electrode active material layer 28 is larger than the longitudinal dimension of the positive electrode active material layer 25, and the lateral dimension of the negative electrode active material layer 28 is the lateral direction of the positive electrode active material layer 25. Is larger than the size of.

As shown in FIG. 3, in a state where the positive electrode 21 and the negative electrode 22 are laminated, the first to fourth edge portions 24a to 24d of the positive electrode current collector 24 are the first to first ones of the negative electrode current collector 27. It is located inside the four edges 27a to 27d.

The separator 23 has a rectangular shape. The separator 23 has a first edge portion 23a extending in the longitudinal direction and a second edge portion 23b extending in the longitudinal direction and located on the side opposite to the first edge portion 23a in the lateral direction. The separator 23 has a third edge portion 23c extending in the lateral direction and a fourth edge portion 23d extending in the lateral direction and located on the opposite side of the third edge portion 23c in the longitudinal direction. The longitudinal dimension of the separator 23 is the same as the longitudinal dimension of the negative electrode current collector 27, and the lateral dimension of the separator 23 is the same as the lateral dimension of the negative electrode current collector 27. Therefore, the longitudinal dimension of the separator 23 is larger than the longitudinal dimension of the positive electrode current collector 24, and the lateral dimension of the separator 23 is larger than the lateral dimension of the positive electrode current collector 24.

In the following, the direction in which the positive electrode 21 and the negative electrode 22 are laminated is referred to as the stacking direction. Further, the direction along the first edge portion 24a of the positive electrode current collector 24 and the first edge portion 27a of the negative electrode current collector 27 is the first direction, and the direction orthogonal to both the first direction and the stacking direction is the second direction. And. In the present embodiment, the first direction coincides with the longitudinal direction of the positive electrode current collector 24 and the negative electrode current collector 27, and the second direction coincides with the lateral direction of the positive electrode current collector 24 and the negative electrode current collector 27. To do.

As shown in FIGS. 1 and 4, the electrode assembly 12 has a positive electrode tab group 15 on which positive electrode tabs 26 are laminated, and a negative electrode tab group 15 on which negative electrode tabs 26 are laminated. The tab group 15 is formed by collecting and stacking the tabs 26 on the first end side in the stacking direction. The tab group 15 of the positive electrode has a first foil collecting portion 15a as a foil collecting portion in which portions located on the first end side in the stacking direction of each tab 26 are laminated, and a first foil collecting portion 15a of each tab 26. It has a first extending portion 15b composed of a portion located between the constituent portion and the first edge portion 24a of the positive electrode current collector 24. The tab group 15 of the negative electrode has a first foil collecting portion 15a as a foil collecting portion in which portions located on the first end side in the stacking direction of each tab 26 are laminated, and a first foil collecting portion 15a of each tab 26. It has a first extending portion 15b composed of a portion located between the constituent portion and the first edge portion 27a of the negative electrode current collector 27. The tab group 15 of the positive electrode and the negative electrode has a second extension as an extension portion that extends toward the second end side opposite to the first end side in the stacking direction by bending the first foil collecting portion 15a. The portion 15c and the second foil collecting portion 15d which is continuous with the second extending portion 15c on the second end side in the stacking direction and in which the portions located on the second end side in the stacking direction in each tab 26 are laminated. Have. The tab group 15 of the positive electrode and the negative electrode has a folded-back portion 15e extending toward the first end side in the stacking direction by bending the second foil collecting portion 15d.

As shown in FIG. 1, in the electrode assembly 12, the surface on which the tab group 15 of the positive electrode and the negative electrode exists is referred to as the tab side end surface 12a, and the surface opposite to the tab side end surface 12a is referred to as the bottom side end surface 12b. In the present embodiment, the tab side end surface 12a is composed of an end surface along the first edge portion 27a of the negative electrode electrode 22 and a first edge portion 23a of the separator 23. Further, the bottom end surface 12b is composed of an end surface along the second edge portion 24b of the positive electrode electrode 21, an end surface along the second edge portion 27b of the negative electrode electrode 22, and a second edge portion 23b of the separator 23. The tab side end surface 12a is a surface facing the inner surface 14a of the lid 14, and the bottom side end surface 12b is a surface facing the bottom wall 13b of the case body 13.

In the electrode assembly 12, the end face located at the first end in the stacking direction is referred to as the first end face 12c, and the end face located at the second end in the stacking direction is referred to as the second end face 12d. The first end surface 12c is composed of the negative electrode 22 located at the first end in the stacking direction, and the second end surface 12d is composed of the negative electrode 22 located at the second end in the stacking direction. The first end surface 12c and the second end surface 12d are surfaces facing the long side wall 13c of the case body 13. The distance from the first end surface 12c to the second end surface 12d is defined as the dimension in the stacking direction of the electrode assembly 12.

The dimensions of the electrode assembly 12 in the stacking direction are such that the inner surface of one long side wall 13c of the case body 13 and the inner surface of the other long side wall 13c are arranged in order to improve the insertability of the electrode assembly 12 into the case body 13. It is set shorter than the distance. Therefore, in a state where the electrode assembly 12 is housed in the case body 13, at least one of the first end surface 12c and one long side wall 13c and the second end surface 12d and the other long side wall 13c There will be a gap.

In the electrode assembly 12, the end face located at one end in the first direction is referred to as the third end face 12e, and the end face located at the other end in the first direction is referred to as the fourth end face 12f. The third end surface 12e is composed of an end surface along the third edge portion 27c of the negative electrode electrode 22 and a third edge portion 23c of the separator 23. The fourth end surface 12f is composed of an end surface along the fourth edge portion 27d of the negative electrode electrode 22 and a fourth edge portion 23d of the separator 23. The third end surface 12e and the fourth end surface 12f are surfaces facing the short side wall 13d of the case body 13.

As shown in FIGS. 3 and 4, the electrode assembly 12 has a first laminated portion 121 in which positive electrode 21 and negative electrode 22 are alternately laminated. In the first laminated portion 121, the positive electrode current collector 24, the positive electrode active material layer 25, the separator 23, the negative electrode current collector 27, and the negative electrode active material layer 28 are laminated. That is, in the first laminated portion 121, the positive electrode active material layer 25 and the negative electrode active material layer 28 are alternately laminated.

The electrode assembly 12 has a second laminated portion 122 in which a portion of the negative electrode electrode 22 that protrudes from the tab side edge portion 25a of the positive electrode active material layer 25 is laminated. In the second laminated portion 122, the uncoated portion 24e of the positive electrode current collector 24, the separator 23, the negative electrode current collector 27, and the negative electrode active material layer 28 are laminated. That is, in the second laminated portion 122, the portion of the negative electrode active material layer 28 that protrudes from the edge portion of the positive electrode active material layer 25 is laminated. The second laminated portion 122 is located on the tab group 15 side of the first laminated portion 121 in the second direction.

The electrode assembly 12 has a third laminated portion 123 in which a portion of the negative electrode electrode 22 that protrudes from the second edge portion 24b of the positive electrode current collector 24 is laminated. The electrode assembly 12 has a fourth laminated portion 124 in which a portion of the negative electrode electrode 22 that protrudes from the third edge portion 24c of the positive electrode current collector 24 is laminated. The electrode assembly 12 has a fifth laminated portion 125 in which a portion of the negative electrode electrode 22 that protrudes from the fourth edge portion 24d of the positive electrode current collector 24 is laminated. In the third to fifth laminated portions 123 to 125, the negative electrode current collector 27, the negative electrode active material layer 28, and the separator 23 are laminated. That is, in the third to fifth laminated portions 123 to 125, the portions of the negative electrode active material layer 28 that protrude from the edge portion of the positive electrode active material layer 25 are laminated.

The first end surface 12c and the second end surface 12d of the electrode assembly 12 each have a first laminated region A1 on which the first laminated portion 121 is projected and a second laminated region A2 on which the second laminated portion 122 is projected. .. The second laminated region A2 is located on the tab group 15 side of the first laminated region A1 in the second direction. The first end surface 12c and the second end surface 12d of the electrode assembly 12 each have a third laminated region A3 on which the third laminated portion 123 is projected. The third laminated region A3 is located on the side opposite to the second laminated region A2 with the first laminated region A1 in the second direction. The first end surface 12c and the second end surface 12d of the electrode assembly 12 each have a fourth laminated region A4 on which the fourth laminated portion 124 is projected and a fifth laminated region A5 on which the fifth laminated portion 125 is projected. .. The fourth laminated region A4 and the fifth laminated region A5 are located so as to sandwich the first laminated region A1 in the first direction.

As shown in FIG. 1, the secondary battery 10 includes a positive electrode and a negative electrode terminal structure 16.
The terminal structure 16 includes a plate-shaped conductive member 17. The conductive member 17 is arranged along the inner surface 14a of the lid 14 between the inner surface 14a of the lid 14 and the tab side end surface 12a of the electrode assembly 12. Further, as shown in FIG. 4, the conductive member 17 is arranged on the second end side in the stacking direction. The electrode assembly 12 and the conductive member 17 are electrically connected by joining the second extending portion 15c of the tab group 15 having the same pole and the conductive member 17.

The terminal structure 16 includes a drawer terminal 18. Each drawer terminal 18 has a plate-shaped base portion 18a and a shaft portion 18b protruding from the base portion 18a. The conductive member 17 and the drawer terminal 18 are electrically connected by joining the base portion 18a of the same pole and the conductive member 17.

The terminal structure 16 includes a plate-shaped external terminal 19 arranged along the outer surface 14b of the lid 14. The external terminal 19 is electrically connected to the shaft portion 18b of the drawer terminal 18. A bus bar as an external device (not shown) that electrically connects the secondary batteries 10 to each other can be fixed to the external terminal 19.

As shown in FIGS. 1 and 2, the secondary battery 10 includes an outer insulating member 31 arranged between the outer terminal 19 and the outer surface 14b of the lid 14. The outer insulating member 31 insulates the outer terminal 19 and the lid 14. Further, the secondary battery 10 includes an inner insulating member 32 arranged between the base portion 18a of the drawer terminal 18 and the inner surface 14a of the lid 14. The inner insulating member 32 insulates the drawer terminal 18 and the lid 14.

Although not shown, the shaft portion 18b of the drawer terminal 18 penetrates the lid 14, the outer terminal 19, the outer insulating member 31, and the inner insulating member 32. Further, the portion of the shaft portion 18b that protrudes from the outer insulating member 31 is crimped. As a result, the drawer terminal 18, the outer terminal 19, the outer insulating member 31, and the inner insulating member 32 are fixed to the lid 14.

As shown in FIG. 4, the secondary battery 10 includes an insulating sheet 33 that covers the end faces of the electrode assembly 12 excluding the tab side end faces 12a. In FIG. 1, the insulating sheet 33 is not shown. The insulating sheet 33 is interposed between the electrode assembly 12 and the case body 13 to insulate the electrode assembly 12 and the case body 13. The insulating sheet 33 has a first portion 33a arranged between the electrode assembly 12 and the long side wall 13c of the case body 13 on the first end side in the stacking direction, and the electrode assembly 12 on the second end side in the stacking direction. It has a second portion 33b arranged between the case body 13 and the long side wall 13c of the case body 13. The dimensions of the first portion 33a and the second portion 33b in the second direction are longer than the distance from the tab side end surface 12a to the bottom side end surface 12b of the electrode assembly 12. A part of the first portion 33a and the second portion 33b is in a state of protruding toward the lid 14 side from the tab side end surface 12a of the electrode assembly 12.

As shown in FIG. 1, the secondary battery 10 includes an insulating cover 34 arranged in the case 11. The insulating cover 34 includes a first cover 35 attached from the first end side in the stacking direction and a second cover 36 attached from the second end side in the stacking direction.

As shown in FIG. 4, the first cover 35 has a rectangular first component 51 and a thickness of the first component 51 from one of the long edges of the pair of long edges 51 of the first component 51. It has a rectangular second component 52 extending in the direction. The first component 51 is arranged between the inner surface 14a of the lid 14 and the conductive member 17. The lateral direction of the first component 51 coincides with the stacking direction. The second component 52 covers the first foil collecting portion 15a of the tab group 15 from the first end side in the stacking direction. The longitudinal direction of the second component 52 coincides with the longitudinal direction of the first component 51.

The second component 52 has a first tab insulating portion 52a and a first interposing portion 52b continuous with the first tab insulating portion 52a. The first tab insulating portion 52a is a portion of the second constituent portion 52 located on the lid 14 side of the tab side end surface 12a of the electrode assembly 12 in the second direction, and the first intervening portion 52b is the second constituent portion. It is a portion of the electrode assembly 12 located on the bottom side end surface 12b side of the tab side end surface 12a in the second direction in 52. The first tab insulating portion 52a is arranged between the first foil collecting portion 15a of the tab group 15 and the long side wall 13c of the case main body 13, and insulates the tab group 15 and the case main body 13. The first intervening portion 52b is interposed between the second laminated region A2 of the first end surface 12c of the electrode assembly 12 and the long side wall 13c of the case body 13.

The end surface 521 on the tab group 15 side of the first tab insulating portion 52a is separated from the end surface 171 on the first tab insulating portion 52a side of the conductive member 17. The first foil collecting portion 15a of the tab group 15 is located between the end surface 171 on the first tab insulating portion 52a side of the conductive member 17 and the end surface 521 on the tab group 15 side of the first tab insulating portion 52a. In the present embodiment, the facing surface 522 of the first intervening portion 52b facing the first end surface 12c is inclined so as to be separated from the first tab insulating portion 52a from the second end side to the first end side in the stacking direction. It is an inclined surface.

Further, as shown in FIG. 1, the second component 52 has a locking portion 53 projecting from a surface facing the tab group 15. The locking portion 53 includes a claw portion 53a at the tip end portion.
The first cover 35 has a protruding portion 54 protruding from the surface of the second component 52 facing the tab group 15 toward the second end side in the stacking direction. The protruding portion 54 supports the first foil collecting portion 15a of the tab group 15 from the electrode assembly 12 side. In the present embodiment, the protruding portion 54 is arranged only in the portion where the tab group 15 is located in the first direction. Further, the tip surface 54a of the protruding portion 54 is inclined so as to be separated from the first tab insulating portion 52a from the first end side to the second end side in the stacking direction.

The second cover 36 has a rectangular shape extending in the thickness direction of the first cover portion 61 from one long edge portion of the rectangular first cover portion 61 and the pair of long edge portions of the first cover portion 61. It has a second cover portion 62 of the above.

The first cover portion 61 is arranged between the inner surface 14a of the lid 14 and the conductive member 17. The lateral direction of the first cover portion 61 coincides with the stacking direction. Although not shown, the first cover portion 61 has ribs on a surface opposite to the surface facing the conductive member 17. The rib has a locking recess that is recessed toward the side opposite to the conductive member 17. The first cover 35 and the second cover 36 are integrally assembled by engaging the claw portion 53a of the locking portion 53 with the locking recess.

The second cover portion 62 covers the second foil collecting portion 15d of the tab group 15 from the second end side in the stacking direction. The longitudinal direction of the second cover portion 62 coincides with the longitudinal direction of the first cover portion 61.
The second cover portion 62 has a second tab insulating portion 62a and a second interposing portion 62b continuous with the second tab insulating portion 62a. The second tab insulating portion 62a is a portion of the second cover portion 62 located on the lid 14 side of the tab side end surface 12a of the electrode assembly 12 in the second direction, and the second intervening portion 62b is the second cover portion. It is a portion of the electrode assembly 12 located on the bottom side end surface 12b side of the tab side end surface 12a in the second direction in 62. The second tab insulating portion 62a is arranged between the second foil collecting portion 15d of the tab group 15 and the long side wall 13c of the case main body 13, and insulates the tab group 15 and the case main body 13. The second intervening portion 62b is interposed between the second laminated region A2 of the second end surface 12d of the electrode assembly 12 and the case body 13. In the present embodiment, the facing surface 622 facing the second end surface 12d of the second intervening portion 62b is inclined so as to be separated from the second tab insulating portion 62a from the first end side to the second end side in the stacking direction. It is an inclined surface.

Further, the second cover 36 has a rectangular third cover portion 63 extending from the surface of the second cover portion 62 facing the tab group 15 to the first end side in the stacking direction. The third cover portion 63 faces the first cover portion 61. The third cover portion 63 is arranged between the first extending portion 15b of the tab group 15 and the folded portion 15e. A part of the second extending portion 15c, the second foil collecting portion 15d, and a part of the folded portion 15e in the tab group 15 are divided by the conductive member 17, the second cover portion 62, and the third cover portion 63. It is in a state of being in the gap.

As shown in FIG. 1, the second cover 36 has a fourth cover portion 64 continuous with one end in the longitudinal direction of the third cover portion 63 and a second cover portion 64 continuous with the other end in the longitudinal direction of the third cover portion 63. It has 5 cover parts 65. The fourth cover portion 64 is arranged between the portion of the positive electrode conductive member 17 to which the base portion 18a is joined and the tab side end surface 12a of the electrode assembly 12, and the fifth cover portion 65 is the negative electrode conductive member 17. It is arranged between the portion to which the base portion 18a is joined and the tab side end surface 12a of the electrode assembly 12.

The operation of the first embodiment will be described.
The second component 52 of the first cover 35 has a first intervening portion 52b. The first intervening portion 52b suppresses the negative electrode 22 located on the first end side in the stacking direction from bending toward the long side wall 13c side of the case body 13. Therefore, it is possible to suppress the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22.

Further, the second cover portion 62 of the second cover 36 has a second intervening portion 62b. The second intervening portion 62b suppresses the negative electrode 22 located on the second end side in the stacking direction from bending toward the long side wall 13c side of the case body 13. Therefore, it is possible to suppress the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22.

The effect of the first embodiment will be described.
(1-1) The second component 52 of the first cover 35 is a first interposition arranged between the second laminated region A2 of the first end surface 12c of the electrode assembly 12 and the long side wall 13c of the case body 13. It has a part 52b. The first intervening portion 52b suppresses the negative electrode 22 located on the first end side in the stacking direction from bending toward the long side wall 13c side of the case body 13. Therefore, it is possible to suppress the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22.

(1-2) The second cover portion 62 of the second cover 36 is a second interposition arranged between the second laminated region A2 of the second end surface 12d of the electrode assembly 12 and the long side wall 13c of the case body 13. It has a part 62b. The second intervening portion 62b suppresses the negative electrode 22 located on the second end side in the stacking direction from bending toward the long side wall 13c side of the case body 13. Therefore, it is possible to suppress the spread of the tab group 15 in the stacking direction due to the bending of the tab 26.

(1-3) When there is no protruding portion 54, the first foil collecting portion 15a of the tab group 15 crushes the portion located on the tab side end surface 12a of the electrode assembly 12 on the first end side in the stacking direction. The negative electrode 22 located on the first end side in the stacking direction may bend. On the other hand, in the present embodiment, the first foil collecting portion 15a is supported by the protruding portion 54. Therefore, it is possible to prevent the portion of the tab-side end surface 12a of the electrode assembly 12 located on the first end side in the stacking direction from being crushed by the first foil collecting portion 15a. Therefore, the bending of the negative electrode 22 is further suppressed. Therefore, the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22 can be further suppressed.

(1-4) When there is no gap between the end surface 171 on the first tab insulating portion 52a side of the conductive member 17 and the end surface 521 on the tab group 15 side of the first tab insulating portion 52a, the first foil collecting portion 15a Is crushed between the conductive member 17 and the tab side end surface 12a of the electrode assembly 12, and the portion of the electrode assembly 12 tab side end surface 12a located on the first end side in the stacking direction is the first foil collecting portion. It is crushed by 15a. Therefore, the negative electrode 22 located on the first end side in the stacking direction tends to bend toward the case 11.

On the other hand, the first foil collecting portion 15a is located in the gap between the end surface 171 on the first tab insulating portion 52a side of the conductive member 17 and the end surface 521 on the tab group 15 side of the first tab insulating portion 52a. Therefore, the first foil collecting portion 15a is less likely to be crushed by the conductive member 17. Therefore, the portion of the tab-side end surface 12a of the electrode assembly 12 located on the first end side in the stacking direction is suppressed from being crushed by the first foil collecting portion 15a, and is located on the first end side in the stacking direction. The negative electrode 22 is further suppressed from bending toward the long side wall 13c of the case body 13. Therefore, the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22 can be further suppressed.

(1-5) When the secondary battery 10 is used, the positive electrode 21 and the negative electrode 22 expand toward the protrusion 54. At this time, since the protruding portion 54 is arranged only in the portion where the tab group 15 is located in the first direction, the interference between the expanded negative electrode electrode 22 and the protruding portion 54 can be minimized.

(1-6) When the protruding portion 54 supports the first foil collecting portion 15a of the tab group 15 from the electrode assembly 12 side, the foil collecting position of the tab 26 forming the tab group 15 is the tip surface of the protruding portion 54. It is set on the second end side in the stacking direction with respect to 54a. In the present embodiment, the tip surface 54a of the protruding portion 54 is inclined so as to be separated from the first tab insulating portion 52a from the first end side to the second end side in the stacking direction. Therefore, as compared with the case where the tip surface 54a of the protrusion 54 is not inclined, the tab 26 located on the first end side in the stacking direction is placed on the second end side in the stacking direction with respect to the tip surface 54a of the protrusion 54. It becomes easier to turn to.

(1-7) When the first intervening portion 52b is interposed between the first laminated region A1 of the first end surface 12c of the electrode assembly 12 and the case body 13, the positive electrode 21 and the negative electrode electrode are formed in the first laminated region A1. Unbalanced surface pressure acting on 22 can cause lithium precipitation. On the other hand, in the present embodiment, the first intervening portion 52b does not intervene between the first laminated region A1 of the first end surface 12c of the electrode assembly 12 and the case body 13. Therefore, it is possible to avoid the precipitation of lithium due to the uneven surface pressure.

Similarly, when the second intervening portion 62b is interposed between the first laminated region A1 of the second end surface 12d of the electrode assembly 12 and the case body 13, the positive electrode 21 and the negative electrode 22 are formed in the first laminated region A1. Unbalanced surface pressure can cause lithium precipitation. On the other hand, in the present embodiment, the second intervening portion 62b does not intervene between the first laminated region A1 of the second end surface 12d of the electrode assembly 12 and the case body 13. Therefore, it is possible to avoid the precipitation of lithium due to the uneven surface pressure.

(1-8) By providing the first intervening portion 52b and the second interposing portion 62b in the insulating cover 34 which is an existing configuration, the stacking direction of the electrode assembly 12 without increasing the number of parts of the secondary battery 10. Can suppress the spread to.

(Second Embodiment)
Hereinafter, a second embodiment in which the power storage device is embodied in a secondary battery will be described with reference to FIG. In the second embodiment, the configurations of the insulating sheet 33 and the insulating cover 34 are different from those in the first embodiment. Therefore, the configurations of the insulating sheet 33 and the insulating cover 34 will be mainly described, and the description of the same configuration as that of the first embodiment will be omitted.

As shown in FIG. 5, in the first cover 35 of the second embodiment, the first intervening portion 52b of the second component portion 52 is omitted. That is, the second component 52 has only the first tab insulating portion 52a and the protruding portion 54. Further, in the second cover 36, the second intervening portion 62b of the second cover portion 62 is omitted. That is, the second cover portion 62 has only the second tab insulating portion 62a.

The first portion 33a of the insulating sheet 33 is bent so as to bulge toward the electrode assembly 12 side from the first creeping portion 37a along the inner surface of the long side wall 13c of the case body 13 and the first creeping portion 37a. It has a part 37b. The first bent portion 37b is U-shaped in a cross-sectional view of the first portion 33a. The first bent portion 37b has a pair of standing portions 371 that are continuous with the first creeping portion 37a, and a connecting portion 372 that connects the standing portions 371 to each other. The first bent portion 37b is arranged between the second laminated region A2 of the first end surface 12c of the electrode assembly 12 and the inner surface of the long side wall 13c of the case body 13. The connecting portion 372 comes into contact with the first end surface 12c of the electrode assembly 12. The portion of the first creeping portion 37a located closer to the lid 14 than the first bent portion 37b in the second direction is located between the first tab insulating portion 52a and the long side wall 13c of the case body 13.

Further, the second portion 33b of the insulating sheet 33 is bent so as to bulge toward the electrode assembly 12 side from the second creeping portion 38a along the inner surface of the long side wall 13c of the case body 13 and the second creeping portion 38a. It has two bent portions 38b. The second bent portion 38b is U-shaped in a cross-sectional view of the second portion 33b. The second bent portion 38b has a pair of standing portions 381 that are continuous with the second creeping portion 38a, and a connecting portion 382 that connects the standing portions 381 to each other. The second bent portion 38b is arranged between the second laminated region A2 of the second end surface 12d of the electrode assembly 12 and the inner surface of the long side wall 13c of the case body 13. The connecting portion 382 comes into contact with the second end surface 12d of the electrode assembly 12. The portion of the second creeping portion 38a located closer to the lid 14 than the second bent portion 38b in the second direction is located between the second tab insulating portion 62a and the long side wall 13c of the case body 13.

The operation of the second embodiment will be described.
The first portion 33a of the insulating sheet 33 is a first curved portion 37a along the inner surface of the long side wall 13c of the case body 13, and a first bent portion that is bent so as to bulge toward the electrode assembly 12 side from the first creeping portion 37a. It has a part 37b. The first bent portion 37b is arranged between the second laminated region A2 of the first end surface 12c of the electrode assembly 12 and the long side wall 13c of the case body 13. The first bent portion 37b suppresses the negative electrode 22 located on the first end side in the stacking direction from bending toward the long side wall 13c side of the case body 13. Therefore, it is possible to suppress the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22.

The second portion 33b of the insulating sheet 33 is bent so as to bulge toward the electrode assembly 12 side from the second creeping portion 38a along the inner surface of the long side wall 13c of the case body 13 and the second creeping portion 38a. It has a part 38b. The second bent portion 38b is arranged between the second laminated region A2 of the second end surface 12d of the electrode assembly 12 and the long side wall 13c of the case body 13. The second bent portion 38b suppresses the negative electrode 22 located on the second end side in the stacking direction from bending toward the long side wall 13c side of the case body 13. Therefore, it is possible to suppress the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22.

The effect of the second embodiment will be described. In the second embodiment, in addition to the effects (1-3) to (1-6) of the first embodiment, the following effects can be obtained.
(2-1) The first portion 33a of the insulating sheet 33 has a first bent portion 37b arranged between the second laminated region A2 of the first end surface 12c of the electrode assembly 12 and the case body 13. The first bent portion 37b prevents the tab 26 located on the first end side in the stacking direction from bending toward the long side wall 13c side of the case body 13. Therefore, it is possible to suppress the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22.

(2-2) The second portion 33b of the insulating sheet 33 has a second bent portion 38b arranged between the second laminated region A2 of the second end surface 12d of the electrode assembly 12 and the case body 13. The second bent portion 38b prevents the tab 26 located on the second end side in the stacking direction from bending toward the long side wall 13c side of the case body 13. Therefore, it is possible to suppress the spread of the electrode assembly 12 in the stacking direction due to the bending of the negative electrode electrode 22.

(2-3) When the first bent portion 37b is interposed between the first laminated region A1 of the first end surface 12c of the electrode assembly 12 and the case body 13, the positive electrode 21 and the negative electrode electrode are formed in the first laminated region A1. Unbalanced surface pressure acting on 22 can cause lithium precipitation. On the other hand, in the present embodiment, the first bent portion 37b does not intervene between the first laminated region A1 of the first end surface 12c of the electrode assembly 12 and the case body 13. Therefore, it is possible to avoid the precipitation of lithium due to the uneven surface pressure.

Similarly, when the second bent portion 38b is interposed between the first laminated region A1 of the second end surface 12d of the electrode assembly 12 and the case body 13, the positive electrode 21 and the negative electrode 22 are formed in the first laminated region A1. Since the surface pressure acting is uneven, it may cause lithium precipitation. On the other hand, in the present embodiment, the second bent portion 38b does not intervene between the first laminated region A1 of the second end surface 12d of the electrode assembly 12 and the case body 13. Therefore, it is possible to avoid the precipitation of lithium due to the uneven surface pressure.

(2-4) By providing the first bent portion 37b and the second bent portion 38b on the insulating sheet 33 having the existing configuration, the stacking direction of the electrode assembly 12 without increasing the number of parts of the secondary battery 10. Can suppress the spread to.

(2-5) The first bent portion 37b is U-shaped. Therefore, for example, the contact area between the first bent portion 37b and the first end surface 12c of the electrode assembly 12 can be increased as compared with the case where the first bent portion 37b is V-shaped. Therefore, it is possible to further suppress the negative electrode 22 located on the first end side in the stacking direction from bending toward the long side wall 13c side of the case body 13.

Similarly, the second bent portion 38b is U-shaped. Therefore, for example, the contact area between the second bent portion 38b and the second end surface 12d of the electrode assembly 12 can be increased as compared with the case where the second bent portion 38b is V-shaped. Therefore, it is possible to further suppress the negative electrode 22 located on the second end side in the stacking direction from bending to the long side wall 13c of the case body 13.

The first embodiment and the second embodiment can be modified and implemented as follows. The first embodiment, the second embodiment, and the modified examples can be implemented in combination with each other within a technically consistent range.

○ In the first embodiment, the insulating sheet 33 may be omitted. In this case, for example, the electrode assembly 12 and the case body 13 are insulated by applying an insulating coat to the inner surface of the case body 13.

○ In the first embodiment, the first tab insulating portion 52a may insulate either one of the tab group 15 of the positive electrode and the tab group 15 of the negative electrode and the case body 13.
○ In the first embodiment, the second tab insulating portion 62a may insulate either one of the tab group 15 of the positive electrode and the tab group 15 of the negative electrode and the case body 13.

○ In the first embodiment, either one of the first cover 35 and the second cover 36 may be omitted. That is, the insulating cover 34 may have a configuration having either the first tab insulating portion 52a or the second tab insulating portion 62a. For example, when the first cover 35 is omitted, the tab group 15 and the case body 13 are extended by extending the first portion 33a of the insulating sheet 33 between the first foil collecting portion 15a of the tab group 15 and the case body 13. Ensure insulation with. Further, by extending the first cover portion 61 of the second cover 36 toward the first end side in the stacking direction, the insulation between the lid 14 and the conductive member 17 is ensured.

○ In the first embodiment, the second component 52 of the first cover 35 has the first intervening portion 52b, and the second cover portion 62 of the second cover 36 does not have the second intervening portion 62b. There may be. On the contrary, the second component 52 of the first cover 35 may not have the first intervening portion 52b, and the second cover portion 62 of the second cover 36 may have the second intervening portion 62b.

○ In the first embodiment, the protruding portion 54 of the second component 52 may be omitted.
○ In the first embodiment, the facing surface 522 of the first intervening portion 52b does not have to be an inclined surface.

○ In the first embodiment, the tip surface 54a of the protrusion 54 does not have to be an inclined surface.
○ In the first embodiment, the facing surface 622 of the second intervening portion 62b does not have to be an inclined surface.

○ In the first embodiment, the third to fifth cover parts 63 to 65 may be omitted.
○ In the second embodiment, the insulating cover 34 may be omitted.
○ In the second embodiment, the first bent portion 37b may be formed by bending the insulating sheet 33 along the folding line, for example, using the folding line provided on the insulating sheet 33 as a mark. Similarly, the second bent portion 38b may be formed by bending the insulating sheet 33 along the folding line, for example, using the folding line provided on the insulating sheet 33 as a mark.

○ In the second embodiment, the first bent portion 37b may be appropriately changed as long as it has a shape that bulges toward the electrode assembly 12 side with respect to the first creeping portion 37a. For example, the first bent portion 37b may be V-shaped or semicircular in cross-sectional view of the first portion 33a.

○ In the second embodiment, the second bent portion 38b may be appropriately changed as long as it has a shape that bulges toward the electrode assembly 12 side with respect to the second creeping portion 38a. For example, the second bent portion 38b may be V-shaped or semicircular in cross-sectional view of the second portion 33b.

○ The first cover 35 and the second cover 36 may be assembled to each other by a structure other than locking between the claw portion 53a and the locking recess.
◯ The electrode assembly 12 may be covered with a plurality of insulating sheets 33. For example, the insulating sheet covering the first end surface 12c of the electrode assembly 12 and the insulating sheet covering the second end surface 12d of the electrode assembly 12 may be separate bodies. Further, the secondary battery 10 has a first insulating sheet portion that insulates the first end surface 12c of the electrode assembly 12 and the case body 13, and a second that insulates the second end surface 12d of the electrode assembly 12 and the case body 13. 2 Only one of the insulating sheet portions may be provided.

○ The end surface 171 on the second tab insulating portion 62a side of the conductive member 17 is not separated from the end surface 521 on the tab group 15 side of the first tab insulating portion 52a, and the first foil collecting portion 15a of the tab group 15 is a conductive member. It does not have to be located between the end surface 171 of 17 and the end surface 521 of the first tab insulating portion 52a.

○ The first end surface 12c of the electrode assembly 12 is composed of the positive electrode 21 located at the first end in the stacking direction, and the second end surface 12d is composed of the positive electrode 21 located at the second end in the stacking direction. You may. In this case, even if there is no gap between the first end surface 12c of the electrode assembly 12 and the inner surface of the long side wall 13c of the case body 13, the lengths of the negative electrode 22 and the case body 13 located at the first end in the stacking direction. A gap is formed between the side wall 13c and the inner surface. Therefore, the negative electrode 22 located on the first end side in the stacking direction may bend toward the long side wall 13c side of the case body 13. Therefore, by arranging the first intervening portion 52b and the first bent portion 37b between the second laminated region A2 of the first end surface 12c of the electrode assembly 12 and the long side wall 13c of the case body 13, the second laminated portion in the stacking direction can be arranged. It is effective to suppress the bending of the negative electrode 22 located on the one end side toward the case body 13.

Further, even if there is no gap between the second end surface 12d of the electrode assembly 12 and the inner surface of the long side wall 13c of the case body 13, the negative electrode 22 located at the second end in the stacking direction and the inner surface of the case body 13 There is a gap between them. Therefore, the negative electrode 22 located on the second end side in the stacking direction may bend toward the long side wall 13c side of the case body 13. Therefore, by arranging the second intervening portion 62b and the second bent portion 38b between the second laminated region A2 of the second end surface 12d of the electrode assembly 12 and the long side wall 13c of the case body 13, the second laminated portion in the stacking direction is arranged. It is effective to suppress the bending of the negative electrode 22 located on the two-end side toward the case body 13.

○ The positive electrode 21 does not have to have the uncoated portion 24e. That is, the positive electrode active material layer 25 may be present in the entire positive electrode current collector 24 excluding the tab 26.
O The dimension of the positive electrode active material layer 25 in the lateral direction may be larger than the dimension of the negative electrode active material layer 28 in the lateral direction. In this case, the positive electrode 21 corresponds to the second electrode of the claim, and the negative electrode 22 corresponds to the first electrode of the claim. Further, in the second laminated region A2, the positive electrode 21 and the separator 23 are alternately laminated.

○ The longitudinal dimension of the positive electrode active material layer 25 may be the same as the lateral dimension of the negative electrode active material layer 28 and the lateral dimension of the separator 23.
○ The positive electrode electrode 21 may have a structure in which the positive electrode active material layer 25 exists on one side of the positive electrode current collector 24. Similarly, the negative electrode electrode 22 may have a structure in which the negative electrode active material layer 28 exists on one side of the negative electrode current collector 27.

○ Depending on the length of the tab 26, the tab group 15 may not have the second foil collecting portion 15d and the folded portion 15e. Even when the tab group 15 does not have the second foil collecting portion 15d and the folded portion 15e, the second cover portion 62 is arranged between the tip portion of the tab group 15 and the case body 13. Therefore, it is preferable to prevent the tip of the tab group 15 from coming into contact with the case body 13.

○ The electrode assembly 12 is not limited to the so-called laminated electrode assembly described in the above embodiment, and is wound by laminating and winding a band-shaped positive electrode, a band-shaped separator, and a band-shaped negative electrode. It may be a revolving electrode assembly.

○ The secondary battery 10 may be a lithium ion secondary battery or another secondary battery. In short, it is sufficient that the ions move between the active material for the positive electrode and the active material for the negative electrode and transfer charges.

○ The power storage device can also be applied to a power storage device other than a secondary battery, such as a capacitor.

10 ... Secondary battery as a power storage device, 11 ... Case, 12 ... Electrode assembly, 12a ... Tab side end face, 12c ... First end face as end face, 12d ... Second end face as end face, 121 ... First laminated portion , 122 ... 2nd laminated portion, 15 ... tab group, 15a ... first foil collecting portion as foil collecting portion, 15c ... second extending portion as extending portion, 17 ... conductive member, 171 ... end face, 21 ... Positive electrode as the first electrode, 22 ... Negative electrode as the second electrode, 24 ... Positive electrode as the first current collector, 24a ... First edge as one side, 25 ... As the first active material layer Positive electrode active material layer, 26 ... Tab, 27 ... Negative electrode current collector as second current collector, 27a ... First edge as one side, 28 ... Negative electrode active material layer as second active material layer, 33a ... First part as the first insulating sheet part, 33b ... Second part as the second insulating sheet part, 34 ... Insulation cover, 37a ... First creeping part as the creeping part, 37b ... First bent part as the bent part , 38a ... Second creeping portion as a creeping portion, 38b ... Second bent portion as a bent portion, 52a ... First tab insulating portion, 52b ... First intervening portion, 54 ... Protruding portion, 54a ... Tip surface, 62a ... 2nd tab insulating portion, 62b ... 2nd interposing portion, A1 ... 1st laminated region, A2 ... 2nd laminated region.

Claims (7)

A first electrode having a first active material layer on at least one side of the sheet-shaped first current collector and a second electrode having a second active material layer on at least one side of the sheet-shaped second current collector are laminated. In addition, an electrode assembly having a tab group in which tabs having a shape protruding from one side of the first current collector and the second current collector are laminated with the same polarity.
A case for accommodating the electrode assembly and
With the insulating cover arranged in the case,
With
The insulating cover is arranged between the tab group and the case on the first end side in the stacking direction in which the first electrode and the second electrode are laminated, and the tab group and the case are connected to each other. It is arranged between the tab group and the case on the first tab insulating portion to be insulated and the second end side opposite to the first end side in the stacking direction to insulate the tab group and the case. Has at least one of the second tab insulation to
When one side of the first current collector and the direction along one side of the second current collector are defined as the first direction, and the direction orthogonal to both the first direction and the stacking direction is defined as the second direction.
The size of the second active material layer in the second direction is larger than the size of the first active material layer in the second direction.
The electrode assembly has a first laminated region in which a first laminated portion in which the first active material layer and the second active material layer are alternately laminated is projected on an end face in the stacking direction, and the second laminated material. A second laminated portion is projected, which is located closer to the tab group than the first laminated portion in the direction and in which the portion of the second active material layer that protrudes from the edge of the first active material layer is laminated. A power storage device having a second laminated region,
The insulating cover is continuous with the first tab insulating portion and is continuous with the first intervening portion interposed between the second laminated region and the case, and is continuous with the second tab insulating portion and the second laminated region. A power storage device having at least one of a second intervening portion interposed between the case and the case. A first electrode having a first active material layer on at least one side of the sheet-shaped first current collector and a second electrode having a second active material layer on at least one side of the sheet-shaped second current collector are laminated. In addition, an electrode assembly having a tab group in which tabs having a shape protruding from one side of the first current collector and the second current collector are laminated with the same polarity.
A case for accommodating the electrode assembly and
The first electrode and the second electrode are arranged between the first end surface of the electrode assembly located on the first end side in the stacking direction, which is the stacking direction, and the case, and the electrode assembly and the case. The first insulating sheet that insulates the case and
It is arranged between the case and the second end surface of the electrode assembly located on the second end side opposite to the first end side in the stacking direction, and insulates the electrode assembly and the case. The second insulating sheet part and
With
When one side of the first current collector and the direction along one side of the second current collector are defined as the first direction, and the direction orthogonal to both the first direction and the stacking direction is defined as the second direction.
The size of the second active material layer in the second direction is larger than the size of the first active material layer in the second direction.
The first end face and the second end face are in a first laminated region on which a first laminated portion in which the first active material layer and the second active material layer are alternately laminated is projected, and in the second direction. The second stacking portion is projected on the tab group side of the first laminated portion and the second laminated portion in which the portion of the second active material layer protruding from the edge of the first active material layer is laminated. A power storage device having an area and
At least one of the first insulating sheet portion and the second insulating sheet portion is arranged between the creeping portion along the inner surface of the case, the second laminated region and the case, and is more than the creeping portion. A power storage device characterized by having a bent portion that is bent so as to bulge toward the electrode assembly side. The tab group is directed toward the second end side in the stacking direction by bending the foil collecting portion and the foil collecting portion in which the portions collected on the first end side in the stacking direction of the tab are laminated. Has an extension part that extends
The power storage device according to claim 1, wherein the insulating cover projects toward the second end side in the stacking direction and has a protruding portion that supports the foil collecting portion from the electrode assembly side. The tab group is directed toward the second end side in the stacking direction by bending the foil collecting portion and the foil collecting portion in which the portions collected on the first end side in the stacking direction of the tab are laminated. Has an extension part that extends
A first tab insulating portion arranged between the foil collecting portion and the case is provided on the first end side in the laminating direction.
The power storage device according to claim 2, wherein the first tab insulating portion has a protruding portion that projects toward the second end side in the stacking direction and supports the foil collecting portion from the electrode assembly side. A conductive member arranged between the extension portion and the case and electrically connected to the tab group is provided.
The third or fourth aspect of the present invention, wherein the foil collecting portion is located between an end surface of the conductive member on the first tab insulating portion side and an end surface of the first tab insulating portion on the tab group side. Power storage device. The power storage device according to any one of claims 3 to 5, wherein the protruding portion is arranged only in a portion where the tab group is located in the first direction. Any one of claims 3 to 6, wherein the tip surface of the protruding portion is inclined so as to be separated from the first tab insulating portion from the first end side to the second end side in the stacking direction. The power storage device described in.