JP2018014289A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device capable of insulating a tab group and a case. In a secondary battery 10, an electrode assembly 14 includes a positive electrode tab group 33 and a negative electrode tab group 34, and each tab group 33, 34 includes a first bent portion 33a, 34a and a first extended portion 33b. , 34b and tip portions 33c, 34c. The first insulating member 43 includes a first covering portion 43a interposed between the first bent portion 33a, 34a and an inner wall surface of the long side wall 12c facing the first bent portion 33a, 34a, and each conductive member 51. , 52 and the inner wall surface of the lid member facing each of the conductive members 51, 52 is provided with a second coating portion 43b. The second insulating member 44 is interposed between the tip portions 33c and 34c and the inner wall surface of the long side wall 12c. [Selection diagram] Figure 1

Description

  The present invention relates to a power storage device.

  Conventionally, vehicles such as EVs (Electric Vehicles) and PHVs (Plug in Hybrid Vehicles) have been mounted with lithium-ion secondary batteries, nickel-hydrogen secondary batteries, etc. as power storage devices that store the power supplied to the motor for travel. Yes. Generally, a secondary battery includes an electrode assembly in which a positive electrode and a negative electrode having an active material layer are stacked in layers, and a case for housing the electrode assembly. The positive electrode and the negative electrode each include a tab having a shape protruding from a part of one side. The secondary battery includes a tab group in which a plurality of tabs are collected for each electrode. The secondary battery includes a conductive member for each electrode joined to each polarity tab group. The secondary battery includes an electrode terminal electrically connected to each conductive member. Extraction of electric power from the secondary battery is performed through the electrode terminals.

  The tab group is a state in which a plurality of tabs are gathered at one end in the stacking direction in which the electrodes are stacked and bent toward the other end in the stacking direction. By bending a plurality of tabs together, the dead space due to the tabs in the case is reduced as compared with the case where the tabs are not bent. The secondary battery includes a tab group and a case, and an insulating member that ensures insulation between the conductive member and the case.

  As shown in FIG. 7, for example, the secondary battery 70 of Patent Document 1 includes both ends in the stacking direction of a current collecting group (tab group) 72 b that collects tabs 72 a, and the side walls of the case 71 facing the both ends. And an insulating member 74 that insulates each current collecting member (conductive member) 73a, 73b and the case 71 from each other. The insulating member 74 has a U-shaped cross section that opens toward the electrode assembly 75. When the secondary battery 70 is manufactured, the insulating member 74 is attached to the current collecting members 73a and 73b from the wall-side surface where the terminal is attached in the case 71.

  Although not shown in the drawings, for the manufacture of the power storage device, a structure in which the electrode terminal and the conductive member are integrated with the case lid is manufactured in advance, and a tab group is joined to the conductive member of the structure. There is a method of manufacturing a power storage device by housing the electrode assembly in a case in a state where the electrode assembly is integrated. The insulating member used in this manufacturing method has an L-shaped cross section, and after the structure is manufactured, a part of the insulating member is inserted and attached between the lid and the conductive member.

Republished WO2013 / 157433

  By the way, in the insulating member mounted after the structure is manufactured, insulation between the conductive member and the case lid and between the one end side in the stacking direction of the tab group and the side wall of the case can be secured. Insulation between the other end side in the direction and the side wall of the case cannot be ensured.

  The present invention has been made paying attention to such problems existing in the prior art, and an object thereof is to provide a power storage device that can insulate a tab group from a case.

  A power storage device for achieving the above object includes an electrode assembly having a structure in which a plurality of rectangular electrodes having different polarities are laminated in a mutually insulated state, and a tab having a shape protruding from a part of one side of the electrode. A tab group stacked with polarity, a case containing the electrode assembly and the tab group and having a wall part, and joined to the tab group and interposed between the wall part and the tab group The tab group has a bent portion bent in the same direction and an extended portion extended in the stacking direction in which the electrodes are stacked from the bent portion. And a first covering portion interposed between the bent portion and an inner wall surface of the side wall of the case facing the bent portion, the conductive member, and an inner wall surface of the wall portion facing the conductive member A first insulating member having a second covering portion interposed between and And the distal end portion of the extending portion, the spirit and second insulating members interposed, in that it comprises between the inner wall surface of the side wall of the case facing the tip portion.

  According to this, as a method for manufacturing a power storage device, a structure in which a conductive member is integrated with a wall portion is manufactured in advance, and a tab group is joined to the conductive member of the structure to form an electrode assembly. After integration, there is a method in which the electrode assembly is accommodated in a case in a state in which the tab group is bent to form a bent portion and an extended portion. In this method, the first insulating member is attached to the structure by inserting the second covering portion between the wall portion and the conductive member. In the manufactured power storage device, the first insulating member is interposed between the bent portion and the inner wall surface of the side wall of the case, and between the conductive member and the inner wall surface of the wall portion of the case. A second insulating member is interposed between the tip of the portion and the inner wall surface of the side wall of the case. As a result, even in a power storage device including a first insulating member of a type in which the second covering portion is inserted between the wall portion and the conductive member, the tab group and the case can be insulated.

  In the power storage device, the second insulating member is closest to the electrode assembly at the first contact portion that contacts the inner wall surface side surface of the wall portion in the second covering portion, and at the extension portion. It is preferable to have a second abutting portion that abuts against the tab and a connecting portion that connects the first abutting portion and the second abutting portion.

  According to this, the tab closest to the electrode assembly in the extending portion is covered from the electrode assembly side by the second contact portion. As a result, it can suppress that the front-end | tip of a tab group contacts an electrode assembly.

In the power storage device, it is preferable that the second insulating member sandwich the tab group, the conductive member, and the second covering portion in an overlapping direction thereof.
According to this, the 2nd insulating member can clamp the extension part of a tab group, an electrically-conductive member, and a 2nd coating | coated part, and can integrate them. For this reason, after attaching the 2nd insulating member, when inserting an electrode assembly in a case, it can control that a 1st insulating member shifts in a laminating direction.

  In the power storage device, the second insulating member is an elastic body, and urges the tab group, the conductive member, and the second covering portion to approach each other along the overlapping direction. Preferably it is.

  According to this, the extension part of the tab group, the conductive member, and the second covering part are sandwiched by the urging force of the second insulating member. For this reason, the extension part of a tab group, a conductive member, and a 2nd coating | coated part can be integrated by a 2nd insulating member, without using adhesion | attachment means, such as an adhesive material. As a result, it is possible to prevent the first insulating member from being displaced in the stacking direction when the electrode assembly is inserted into the case after mounting the second insulating member.

  The power storage device is a secondary battery.

  An object of the present invention is to provide a power storage device that can insulate a tab group from a case.

The disassembled perspective view of the secondary battery except a cover member. The perspective view of a secondary battery. The exploded perspective view of an electrode assembly. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. Sectional drawing which shows the other example of an insulating member. Sectional drawing which shows the other example of an insulating member. The figure which shows background art.

Hereinafter, an embodiment in which the power storage device is embodied as a secondary battery will be described with reference to FIGS.
As shown in FIG. 1 or 2, the secondary battery 10 as the power storage device includes a case 11. The secondary battery 10 includes an electrode assembly 14 in the case 11. The case 11 includes a rectangular box-shaped main body member 12 and a rectangular flat plate-shaped lid member 13 as a wall portion that closes an opening 12 d provided in the main body member 12. The secondary battery 10 is a prismatic battery whose outer shell forms a square shape. The main body member 12 and the lid member 13 are made of metal (for example, stainless steel or aluminum), and the secondary battery 10 is a lithium ion battery.

  As shown in FIG. 1, the main body member 12 has a bottomed cylindrical shape, a rectangular flat bottom 12a, a pair of short side walls 12b erected vertically from a short side edge of the bottom 12a, and a bottom 12a. A pair of long side walls 12c that are vertically arranged from the long side edges of the long side walls.

  The electrode assembly 14 includes a positive electrode terminal 41 that transmits and receives electricity to and from the electrode assembly 14, and a negative electrode terminal 42. The terminals 41 and 42 are attached to the lid member 13 and are disposed on both ends in the longitudinal direction of the lid member 13.

  As shown in FIG. 3, the electrode assemblies 14 are alternately stacked with a plurality of rectangular positive electrodes 21 and a plurality of rectangular negative electrodes 22 insulated from each other via separators 23. Has a structure. The positive electrode 21 and the negative electrode 22 are electrodes having different polarities. The positive electrode 21 has a rectangular positive metal foil (aluminum foil in this embodiment) 21a and a positive electrode active material layer 21b present on both surfaces (surface) of the positive metal foil 21a. The negative electrode 22 has a rectangular negative electrode metal foil (copper foil in this embodiment) 22a and a negative electrode active material layer 22b present on both surfaces (surface) of the negative electrode metal foil 22a.

  The positive electrode 21 has a positive electrode uncoated portion 21d that is not coated with a positive electrode active material along one side 21c of the positive metal foil 21a. The positive electrode 21 includes a positive electrode tab 31 having a shape protruding from a part of one side 21c of the positive electrode uncoated portion 21d. The negative electrode 22 has a negative electrode uncoated portion 22d where no negative electrode active material is applied along one side 22c of the negative electrode metal foil 22a. The negative electrode 22 has a negative electrode tab 32 having a shape protruding from a part of one side 22c of the negative electrode uncoated portion 22d.

  As shown in FIG. 1 or 2, the direction in which the positive electrode 21 and the negative electrode 22 are stacked, in other words, the direction perpendicular to the main surfaces of the positive electrode 21 and the negative electrode 22 is the stacking direction L1, A direction parallel to the sides 21c and 22c having the tabs 31 and 32 of the metal foils 21a and 22a is defined as a longitudinal direction L2.

  In the positive electrode 21 and the negative electrode 22, the positive electrode tabs 31 are arranged in a line along the stacking direction L1, and the negative electrode tab 32 extends along the stacking direction L1 at a position that does not overlap the positive electrode tab 31 in the stacking direction L1. Are stacked in a row.

  As shown in FIG. 1 or FIG. 4, the secondary battery 10 includes a positive electrode tab group 33 on a part of one end surface of the electrode assembly 14. The positive electrode tab group 33 has a structure in which the positive electrode tabs 31 are gathered in a range from one end to the other end in the stacking direction L1 and are bent toward the other end side in the stacking direction L1. The positive electrode tab group 33 includes a first bent portion 33a located on one end side in the stacking direction L1, and a first extending portion 33b having a shape extending from the first bent portion 33a toward the other end side in the stacking direction L1. . The first bent portion 33a has a shape in which all the positive electrode tabs 31 are bent in the same direction.

  The secondary battery 10 includes a negative electrode tab group 34 on a part of one end surface of the electrode assembly 14. The negative electrode tab group 34 has a structure in which the negative electrode tabs 32 are gathered in a range from one end to the other end in the stacking direction L1 and are bent toward the other end side in the stacking direction L1. The negative electrode tab group 34 includes a first bent portion 34a located on one end side in the stacking direction L1, and a first extending portion 34b having a shape extending from the first bent portion 34a toward the other end side in the stacking direction L1. . The first bent portion 34a has a shape in which all the negative electrode tabs 32 are bent in the same direction. The case 11 houses the electrode assembly 14 and the tab groups 33 and 34.

  In the positive electrode tab group 33, the distal end portion 33 c of the first extension portion 33 b has a structure that is bent in two lines so as to approach the electrode assembly 14. The distal end portion 33c has a second bent portion 33d facing the first bent portion 33a in the stacking direction L1, and a second bent portion 33d having a shape extending from the other end side in the stacking direction L1 toward the one end side in the second bent portion 33d. 2 extending portion 33e.

  In the negative electrode tab group 34, the distal end portion 34 c of the first extension portion 34 b has a structure that is bent into two strips so as to approach the electrode assembly 14. The distal end portion 34c has a second bent portion 34d facing the first bent portion 34a in the stacking direction L1, and a second bent portion 34d extending from the other end side in the stacking direction L1 of the second bent portion 34d toward the one end side. 2 extending part 34e.

  The secondary battery 10 includes a positive electrode conductive member 51 as a conductive member joined to the positive electrode tab 31 at one end in the stacking direction in the positive electrode tab group 33. The positive electrode conductive member 51 is interposed between the positive electrode tab group 33 and the lid member 13. The positive electrode conductive member 51 is bonded to the positive electrode tab group 33 by laser welding at a welded portion (not shown) that is a part of the first extending portion 33b. The positive electrode conductive member 51 exchanges electricity with the electrode assembly 14. Further, the secondary battery 10 includes a positive electrode terminal 41 connected to the positive electrode conductive member 51.

  The secondary battery 10 includes a negative electrode conductive member 52 as a conductive member joined to the negative electrode tab 32 at one end of the negative electrode tab group 34 in the stacking direction. The negative electrode conductive member 52 is interposed between the negative electrode tab group 34 and the lid member 13. The negative electrode conductive member 52 is joined to the negative electrode tab group 34 and the welded portion W, which is a part of the extended portion 34b, by laser welding. The negative electrode conductive member 52 exchanges electricity with the electrode assembly 14. Further, the secondary battery 10 includes a negative electrode terminal 42 connected to the negative electrode conductive member 52. Here, the direction in which the tab groups 33 and 34 and the conductive members 51 and 52 overlap (the vertical direction in FIG. 4) is defined as the overlapping direction.

  As shown in FIGS. 1 and 2, the positive electrode conductive member 51 has a rectangular flat plate shape, and is arranged in a state in which the length is along the longitudinal direction L2. The positive electrode conductive member 51 has a tab bonding piece 51 a on one end side in the longitudinal direction of the positive electrode conductive member 51 and a terminal bonding piece 51 b on the other end side. The positive electrode conductive member 51 is bonded to the positive electrode tab group 33 in the tab bonding piece 51a. Further, the positive electrode conductive member 51 is bonded to the positive electrode terminal 41 in the terminal bonding piece 51b.

  The negative electrode conductive member 52 has a rectangular flat plate shape, and is arranged in a state where the length is along the longitudinal direction L2. The negative electrode conductive member 52 has a tab bonding piece 52 a on one end side in the longitudinal direction of the negative electrode conductive member 52 and a terminal bonding piece 52 b on the other end side. The negative electrode conductive member 52 is bonded to the negative electrode tab group 34 in the tab bonding piece 52a. Further, the negative electrode conductive member 52 is bonded to the negative electrode terminal 42 in the terminal bonding piece 52b.

  As shown in FIG. 2, the secondary battery 10 includes an insulating ring 53 that insulates the terminals 41 and 42 from the lid member 13. Each of the terminals 41 and 42 penetrates the lid member 13 while being insulated by the insulating ring 53. Further, the secondary battery 10 includes a square box-like insulating sheet 60. The insulating sheet 60 is formed between the bottom 12a of the case 11 and the bottom surface of the electrode assembly 14, between the short side wall 12b of the case 11 and the short side surface of the electrode assembly 14, and the long side wall 12c of the case 11. It is interposed between the long side surface of the electrode assembly 14.

  As shown in FIGS. 2 and 4, the secondary battery 10 includes a first insulating member 43 that insulates the tab groups 33 and 34 and the main body member 12, and the conductive members 51 and 52 and the lid member 13. 4 shows the positive electrode tab group 33, the first insulating member 43, and the second insulating member 45, the negative electrode tab group 34, the first insulating member 43, and the second insulating member. Since the positional relationship with 45 is the same as that on the positive electrode side, its illustration is omitted.

  The first insulating member 43 is made of an insulating resin. The first insulating member 43 has a rectangular shape when viewed from the lid member 13. The length of the first insulating member 43 is along the longitudinal direction L2 of the electrode assembly 14. The first insulating member 43 is L-shaped when viewed from the short side wall 12b of the case 11.

  The first insulating member 43 is interposed between the first bent portions 33a, 34a of the tab groups 33, 34 and the inner wall surface of the long side wall 12c of the case 11 facing the first bent portions 33a, 34a. 1 covering part 43a, and each 2nd covering part 43b interposed between each electrically-conductive member 51 and 52 and the inner wall face of the cover member 13 facing each electrically-conductive member 51 and 52 are provided. The 1st coating | coated part 43a and the 2nd coating | coated part 43b are rectangular flat plate shape. The length of the first covering portion 43a in the overlapping direction is at least a value obtained by adding the length in the overlapping direction of the tab groups 33 and 34 folded in two and the thickness of the conductive members 51 and 52. Longer is preferred. The length of the second covering portion 43b in the stacking direction L1 is preferably longer than the length of the conductive members 51 and 52 along the stacking direction L1. In FIG. 4, the thicknesses of the first covering portion 43a and the second covering portion 43b are equal, but the thicknesses may be different, and each of the first covering portion 43a and the second covering portion 43b. There is no particular limitation on the thickness.

  The secondary battery 10 includes a second insulating member 44 interposed between the front end portions 33c, 34c of the tab groups 33, 34 and the long side wall 12c of the case 11 facing the front end portions 33c, 34c. The second insulating member 44 is made of an insulating resin and can be elastically deformed. The second insulating member 44 has a rectangular shape when viewed from the lid member 13. In addition, the insulating member 44 is a U-shape that is open in one side in the stacking direction L1 and has a corner when viewed from the short side wall 12b of the case 11.

  The second insulating member 44 has a first abutting portion 44 a that abuts the surface 43 c on the lid member 13 side of the second covering portion 43 b of the first insulating member 43, and the second extension of each tab group 33, 34. It has the 2nd contact part 44b contact | abutted with the tabs 31 and 32 nearest to the electrode assembly 14 in the part 33e and 34e. Further, the second insulating member 44 has a connection portion 44c that connects the first contact portion 44a and the second contact portion 44b.

  The connecting portion 44c is formed on the side of each end portion 33c, 34c of the second bending portions 33d, 34d and the conductive members 51, 52 on the side facing the long side wall 12c of the case 11 along the stacking direction L1. Of the surface and the surface facing the long side wall 12c along the stacking direction L1 in the second covering portion 43b, the surface on the tip end portions 33c, 34c side is covered from the side.

  The length K of the straight line connecting the opposing surfaces of the first contact portion 44a and the second contact portion 44b with the shortest distance is the length in the overlapping direction of the positive electrode tab group 33 folded in two strips, and the positive electrode conductive member 51. The value is the same as or slightly shorter than the value obtained by adding the thickness and the thickness of the second covering portion 43 b of the first insulating member 43. Similarly, the length K of the straight line connecting the opposing surfaces of the first contact portion 44a and the second contact portion 44b with the shortest distance is equal to the length in the overlapping direction of the negative electrode tab group 34 folded in two strips, and the negative electrode conductivity. The value is the same as or slightly shorter than the value obtained by adding the thickness of the member 52 and the thickness of the second covering portion 43 b of the first insulating member 43. The first contact portion 44a and the second contact portion 44b sandwich the tab groups 33 and 34, the conductive members 51 and 52, and the second covering portion 43b of the first insulating member 43 in the overlapping direction. Yes. Further, the second insulating member 44 urges the tab groups 33 and 34, the conductive members 51 and 52, and the second covering portion 43b of the first insulating member 43 so as to approach each other along the overlapping direction. Yes. That is, the second insulating member 44 integrates the tab groups 33 and 34, the conductive members 51 and 52, and the first insulating member 43.

  The length of the second insulating member 44 along the longitudinal direction L2 is longer than the length of the tab groups 33 and 34 along the longitudinal direction L2. Moreover, although the length along the lamination direction L1 of the 1st contact part 44a and the 2nd contact part 44b is equal in FIG. 4, it does not necessarily need to be equal. The length of the second contact portion 44b along the stacking direction L1 is not particularly defined, but is preferably longer than the lengths of the second extending portions 33e and 34e along the stacking direction L1.

  In FIG. 4, the second insulating member 44 has a uniform thickness of the first contact portion 44 a, the second contact portion 44 b, and the connection portion 44 c, but the first contact portion 44 a, The two contact portions 44b and the connection portion 44c may have different thicknesses. The second contact portion 44b preferably has a thickness that does not interfere with the electrode assembly 14.

  In the secondary battery 10 of the present embodiment, the structure including the lid member 13 and the electrode assembly 14 are integrated in advance, and the electrode assembly 14 is first inserted into the main body member 12, and then the lid member 13 is attached. It is manufactured by welding to the main body member 12. Specifically, after each terminal 41, 42 is connected to each conductive member 51, 52, a part of each terminal 41, 42 is passed through the lid member 13. Then, nuts (not shown) are screwed into the terminals 41 and 42 protruding from the lid member 13, and the terminals 41 and 42 are fixed to the lid member 13 to manufacture the structure. Next, the positive electrode tab group 33 is laser welded to the tab joint piece 51 a of the positive electrode conductive member 51 of the structure, and the negative electrode tab group 34 is laser welded to the tab joint piece 52 a of the negative electrode conductive member 52. Then, the lid member 13 and the electrode assembly 14 are integrated.

  The second covering portion 43 b of the first insulating member 43 is inserted between the tab joining pieces 51 a and 52 a and the lid member 13. At this time, the second covering portion 43b is inserted from one end side of the electrode assembly 14 in the stacking direction L1.

  Next, the tab groups 33 and 34 are bent to form first bent portions 33a and 34a, first extending portions 33b and 34b, and tip portions 33c and 34c. Then, the 1st bending parts 33a and 34a used as the one end side of the lamination direction of both tab groups 33 and 34 are covered with the 1st coating | coated part 43a.

  Next, from the other end side in the stacking direction L1, the second insulating member 44 is attached to the tab groups 33 and 34, the tab joining pieces 51a and 52a, and the second covering portion 43b of the first insulating member 43. The tip portions 33c and 34c of the tab groups 33 and 34, the tab joining pieces 51a and 52a, and the second covering portion 43b of the first insulating member 43 are sandwiched in the overlapping direction. Then, the front end portions 33c and 34c on the other end side in the stacking direction of both the tab groups 33 and 34 are covered by the connection portion 44c.

  Next, the electrode assembly 14 is inserted into the main body member 12, and the main body member 12 and the lid member 13 are joined together with the lid member 13 placed on the open end of the electrode assembly 14. Then, the case 11 is formed and the secondary battery 10 is completed.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) The secondary battery 10 includes a first insulating member 43. The first insulating member 43 is interposed between the first bent portions 33a and 34a of the tab groups 33 and 34 and the inner wall surface of the long side wall 12c of the case 11 facing the first bent portions 33a and 34a. A first covering portion 43a; conductive members 51 and 52; and a second covering portion 43b interposed between the inner wall surfaces of the lid member 13 facing the conductive members 51 and 52. Thereby, the 1st bending part 33a, 34a of each tab group 33, 34 and the inner wall surface of the long side wall 12c of the case 11, and each conductive member 51, 52 and the inner wall surface of the cover member 13 can be insulated. Further, the secondary battery 10 includes a second insulating member 44. The second insulating member 44 is a connecting portion interposed between the second bent portions 33d and 34d of the tab groups 33 and 34 and the inner wall surface of the long side wall 12c of the case 11 facing the second bent portions 33d and 34d. 44c. Thereby, the 2nd bending parts 33d and 34d of each tab group 33 and 34 and the long side wall 12c of the case 11 facing the 2nd bending parts 33d and 34d can be insulated. As a result, the secondary member manufactured by assembling the first insulating member 43 and the second insulating member 44 to the structure in which the conductive members 51 and 52 and the terminals 41 and 42 are integrated in advance with the lid member 13. Even in the case of the battery 10, the case 11 can be insulated from both ends of the tab groups 33 and 34 in the stacking direction L1.

  (2) In the second insulating member 44, the length K of the straight line connecting the opposing surfaces of the first contact portion 44a and the second contact portion 44b with the shortest distance is the length of each tab group 33, 34 folded in two. It is the same as or slightly shorter than the value obtained by adding the length in the overlapping direction, the thickness of each conductive member 51, 52, and the thickness of the second covering portion 43 b of the first insulating member 43. The first contact portion 44a and the second contact portion 44b sandwich the tab groups 33 and 34, the conductive members 51 and 52, and the second covering portion 43b. For this reason, the positive electrode tab group 33, the positive electrode conductive member 51, and the second covering portion 43b, and the negative electrode tab group 34, the negative electrode conductive member 52, and the second covering portion 43b can be integrated by the second insulating member 44. As a result, when the electrode assembly 14 is inserted from the opening 12d of the main body member 12, the positional deviation of the first insulating member 43 in the stacking direction L1 can be suppressed.

  (3) The second insulating member 44 is interposed between the second bent portions 33d and 34d of the tab groups 33 and 34 and the inner wall surface of the long side wall 12c of the case 11 facing the second bent portions 33d and 34d. And a second abutting portion 44b that abuts the tabs 31 and 32 closest to the electrode assembly 14 in the second extending portions 33e and 34e of the tab groups 33 and 34, respectively. For this reason, the contact between the second bent portions 33d and 34d of the tab groups 33 and 34 and the long side wall 12c of the case 11 can be more effectively suppressed.

  (4) The second insulating member 44 includes the first contact portion 44a and the second contact portion 44b so that the tab groups 33 and 34, the conductive members 51 and 52, and the second covering portion 43b are overlapped with each other. It is pinched. For this reason, the fluttering of the second extending portions 33e and 34e in the overlapping direction can be suppressed. As a result, the tabs 31 and 32 of the second extending portions 33e and 34e can be prevented from sliding against each other, and the generation of foreign matters such as metal powder due to the sliding contact can be suppressed.

  (5) The welded portion W between each tab group 33, 34 and each conductive member 51, 52 is covered from the lid member 13 side by the second covering portion 43 b of the first insulating member 43. For this reason, when the secondary battery 10 vibrates, the load applied to the welded portion W can be supported by the second covering portion 43b, and the load applied to the welded portion W can be reduced.

In addition, you may change the said embodiment as follows.
In the embodiment, the second insulating member 44 is separated on the positive electrode side and the negative electrode side, but may be integrated.

The first insulating member 43 may be a separate body on the positive electrode side and the negative electrode side.
In the embodiment, the tip portions 33c, 34c of the tab groups 33, 34 have a shape bent in two lines, but the tip portions 33c, 34c of the tab groups 33, 34 may not be bent ( The second bent portions 33d and 34d and the second extending portions 33e and 34e may not be provided).

  In the embodiment, the second insulating member 44 is made of resin, but is not limited to resin. For example, a metal coated with an insulating material (resin or ceramics) may be used.

  In the embodiment, the length K of the straight line connecting the opposing surfaces of the first contact portion 44a and the second contact portion 44b with the shortest distance is the overlapping direction of the positive electrode tab group 33 or the negative electrode tab group 34 folded in two strips. It is assumed that the length is equal to or slightly shorter than the value obtained by adding the length of the positive electrode conductive member 51 or the negative electrode conductive member 52 and the thickness of the second covering portion 43b of the first insulating member 43. However, the above-described length K includes the length in the overlapping direction of the positive electrode tab group 33 or the negative electrode tab group 34 bent in two strips, the thickness of the positive electrode conductive member 51 or the negative electrode conductive member 52, and the first insulating member 43. It may be slightly longer than the value obtained by adding the thickness of the second covering portion 43b.

  As shown in FIG. 5, the second insulating member 45 may be U-shaped when viewed from the short side wall 12 b of the case 11. The second insulating member 45 has a first abutting portion 45 a that abuts the surface 43 c on the lid member 13 side of the second covering portion 43 b of the first insulating member 43, and the second extension of each tab group 33, 34. The portions 33e and 34e have second contact portions 45b that contact the tabs closest to the electrode assembly 14. Further, the second insulating member 45 has a connection portion 45c that connects the first contact portion 45a and the second contact portion 45b. Also in this case, the same effects as the embodiment can be obtained.

  (Circle) as shown in FIG. 6, the 2nd insulating member 46 does not need to have the 2nd contact part 44b. In this case, the second insulating member 46 is interposed between the contact portion 46 a that contacts the surface 43 c on the lid member 13 side of the second covering portion 43 b of the first insulating member 43 and the long side wall 12 c of the case 11. And an extending portion 46b having a shape extending from the contact portion 46a toward the electrode assembly 14. The length in the overlapping direction of the extending portion 46b is longer than the length in the overlapping direction of the tab groups 33 and 34 that are bent in two strips without the extending portion 46b interfering with the electrode assembly 14. Is preferred.

  The second covering portion 43b of the first insulating member 43 has a step-shaped contact piece 43d that contacts the surface of the contact portion 46a on the electrode assembly 14 side on the surface 43c on the lid member 13 side. The depth of the step of the contact piece 43d is preferably the same value as the thickness of the contact portion 46a or larger than the thickness of the contact portion 46a.

  When configured in this manner, the surface 43c on the lid member 13 side of the second covering portion 43b of the first insulating member 43 and the surface on the lid member 13 side of the abutting portion 46a abut against the inner wall surface of the lid member 13. In addition, it is preferable to be sandwiched between the conductive members 51 and 52 and the lid member 13.

  In the embodiment of FIG. 6, the contact portion 46 a of the second insulating member 46 is in contact with the surface 43 c on the lid member 13 side of the second covering portion 43 b of the first insulating member 43, but the second covering portion 43b and the conductive members 51 and 52 may be interposed. In this case, the second covering portion 43b of the first insulating member 43 is brought into contact with the surface of the second covering portion 43b on the electrode assembly 14 side so as to abut on the surface on the lid member 13 side of the contacting portion 46a. It has a piece 43d.

The power storage device may be another power storage device such as an electric double layer capacitor.
In the embodiment, the secondary battery 10 is a lithium ion secondary battery, but is not limited thereto, and may be another secondary battery such as nickel metal hydride. In short, any ion may be used as long as ions move between the positive electrode active material layer and the negative electrode active material layer and transfer charge.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 11 ... Case, 12c ... Long side wall as a side wall, 13 ... Lid member as a wall part, 14 ... Electrode assembly, 21 ... Positive electrode as an electrode, 21c ... One side, 22 ... Negative electrode as electrode, 22c ... One side, 31 ... Positive electrode tab as tab, 32 ... Negative electrode tab as tab, 33 ... Positive electrode tab group as tab group, 34 ... Negative electrode tab group as tab group, 33a, 34a ... first bent portion as a bent portion, 33b, 34b ... first extended portion as an extended portion, 33c, 34c ... tip portion, 43 ... first insulating member, 43a ... first covering portion, 43b ... first 2 covering portions, 44 ... second insulating member, 44a ... first contact portion, 44b ... second contact portion, 44c ... connecting portion, 51 ... positive electrode conductive member as a conductive member, 52 ... negative electrode conductivity as a conductive member Element.

Claims (5)

An electrode assembly having a structure in which a plurality of rectangular electrodes having different polarities are laminated in a mutually insulated state;
A tab group in which tabs in a shape protruding from a part of one side of the electrode are laminated with the same polarity,
A case for accommodating the electrode assembly and the tab group and having a wall;
A conductive member joined to the tab group and interposed between the wall portion and the tab group;
A power storage device comprising:
The tab group has a bent portion bent in the same direction, and an extended portion extended in the stacking direction in which the electrodes are stacked from the bent portion,
Between the first covering portion interposed between the bent portion and the inner wall surface of the side wall of the case facing the bent portion, and between the conductive member and the inner wall surface of the wall portion facing the conductive member A first insulating member having a second covering portion interposed therebetween,
A second insulating member interposed between the distal end portion of the extending portion and the inner wall surface of the side wall of the case facing the distal end portion;
A power storage device comprising: The second insulating member includes a first contact portion that contacts an inner wall surface of the wall portion in the second covering portion;
A second abutting portion that abuts a tab closest to the electrode assembly in the extending portion;
The power storage device according to claim 1, further comprising a connection portion that connects the first contact portion and the second contact portion.   The power storage device according to claim 2, wherein the second insulating member sandwiches the tab group, the conductive member, and the second covering portion in an overlapping direction thereof.   The second insulating member is an elastic body, and biases the tab group, the conductive member, and the second covering portion so as to approach each other along the overlapping direction. The power storage device according to claim 3.   The power storage device according to any one of claims 1 to 4, wherein the power storage device is a secondary battery.

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