JP6160350B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device.

EV (Electric Vehicle) and PHV (Plug in Hybrid)
Vehicles such as “Vehicle” are equipped with a secondary battery as a power storage device that stores power supplied to the driving motor. In general, a secondary battery includes a case that accommodates an electrode assembly, and the electrode assembly is accommodated in the case. And extraction of the electric power from a secondary battery is performed through the electrode terminal connected via the electroconductive member to the positive electrode and negative electrode of an electrode assembly.

  Examples of the electrode assembly include a stacked electrode assembly in which separators are interposed between a plurality of positive electrodes and a plurality of negative electrodes, and a strip-shaped separator between a strip-shaped positive electrode and a strip-shaped negative electrode. There is a wound-type electrode assembly that is wound in a state where a metal is interposed.

  As shown in FIG. 8A, for example, in the secondary battery 80 of Patent Document 1, an electrode assembly 89 accommodated in a case 88 includes a positive electrode plate 81 and a negative electrode plate 82. It has a positive electrode tab 81a, and the negative electrode plate 82 has a negative electrode tab 82a. The plurality of positive electrode tabs 81a are electrically connected to the positive electrode terminal 83 in a stacked state, and the plurality of negative electrode tabs 82a are electrically connected to the negative electrode terminal 84 in a stacked state.

  As shown in FIG. 8B, the positive electrode tab 81a and the positive electrode terminal 83 are joined together by welding in a state where a plurality of positive electrode tabs 83 are stacked on the positive electrode terminal 83, for example. The positive terminal 83 is electrically connected. Similarly, the negative electrode tab 82a and the negative electrode terminal 84 are joined to each other by welding in a state where a plurality of negative electrode tabs 84 are stacked on the negative electrode terminal 84, and all the negative electrode tabs 82a and the negative electrode terminals 84 are electrically connected at the welded portion 90. .

JP 2012-14935 A

  By the way, the plurality of positive electrode tabs 81a and negative electrode tabs 82a may be free ends on the tip side of the welded portion 90, and the positive electrode tabs 81a or the negative electrode tabs 82a that become the free ends are in the case. There is a risk of contacting the electrode 88 or the electrode assembly 89.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a power storage device that can prevent the free end portion of the tab from affecting the electrode assembly and the case.

In order to solve the above-described problem, the power storage device according to claim 1 includes an electrode assembly in a case where electrodes of different poles are stacked in an insulated state, and the electrode for extracting electricity from the electrode. A tab group projecting from one side of the electrode assembly, and a tab group in which the tabs are gathered together along a stacking direction of the electrode assembly on one end surface where the one side of the electrode gathers in the electrode assembly. And a conductive member joined to a tab at one end of the tab group in the stacking direction, wherein the tab group is on one end side of the tab group in the stacking direction. The tabs in a gathered state are folded back toward the other end side opposite to the one end side, and extend from the first folded portion along the stacking direction of the electrode assembly Or A first extending portion in which the conductive portion is positioned, the continuously to the first extending portion, and a second folded portion folded back toward the one end side, the electrode assembly from the second folded portion A second extending portion extending in the laminating direction, and including an attachment member made of an insulating material attached to the tab group from the tip end side of the tab. A first covering portion that covers the conductive member from one end side in the stacking direction of the tab group, and at least one end from the other end side in the stacking direction of the tab group. And a second covering portion that covers the extending portion; a third covering portion that connects the first covering portion and the second covering portion and covers the second folded portion; and the first covering portion And surrounded by the second covering portion and the third covering portion, at least on the tip side from the conducting portion. And all tabs, and summarized in that has an accommodating portion for accommodating the said conductive member overlapped in the stacking direction of the tab group.

According to this, all the tabs and the conductive members are covered from the both end sides in the stacking direction of the tab group on the tip side from the conducting portion, and the leading end side is accommodated from all the tabs and the conducting portions of the conducting member. Is housed in the department. For this reason, even if the power storage device vibrates, the free end portion of the tab located on the front end side from the conducting portion can be prevented from jumping out from the attachment member in the stacking direction. It is possible to prevent the case from affecting the case.
According to this, the tab group folded at the first folded portion is in a state of facing the one end face of the electrode assembly, but this tab group is covered by the second covering portion from the other end side in the stacking direction. ing. For this reason, even if the tabs slidably come into contact with each other in the housing portion and foreign matter is generated and dropped, the foreign matter can be received by the second covering portion.

  Further, in the power storage device, the first covering portion and the second covering portion sandwich all the tabs and the conductive member overlapping in the stacking direction of the tab group on the tip side of the conducting portion. Is preferred.

  According to this, the first cover portion and the second cover portion can prevent the free end portion of the tab on the front end side from flapping from flapping. As a result, it is possible to suppress sliding contact between the free ends of the tabs, and it is possible to suppress the generation of foreign matter due to the sliding contact.

  The power storage device further includes an insulating sheet that insulates the electrode assembly from the case, and the insulating sheet protrudes from the one end face along the protruding direction of the tab from the one end face of the electrode assembly. It is preferable to provide a protruding portion.

  According to this, the tab group which protruded from the one end surface of the electrode assembly is surrounded by the protrusion part. Therefore, in the tab group, the portion that is not covered by the attachment member and the case can be insulated by the protruding portion. The one end side in the stacking direction of the tab group, the other end side in the stacking direction of the tab group, and the tip of the tab can be insulated from the case by the attachment member. Therefore, the tab group can be reliably insulated from the case by the attachment member and the protruding portion.

  The power storage device is a secondary battery.

  It is possible to prevent the free end portion of the tab from affecting the electrode assembly and the case.

The perspective view of a secondary battery. The exploded perspective view of an electrode assembly. The exploded perspective view of a secondary battery. FIG. 4 is a sectional view taken along line 4-4 of FIG. The partial front sectional view which shows the inside of a secondary battery. The partial front sectional view which shows another example. The fragmentary sectional view which shows another example of an attachment member. (A) And (b) is a 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, a secondary battery 10 as a power storage device includes a case 11 that forms the outer shape thereof. The case 11 includes a rectangular box-shaped container 12 and a rectangular flat lid 13 that closes an opening provided in the container 12. For this reason, the secondary battery 10 is a square battery whose outer shape is a square. The container 12 and the lid 13 are made of metal, and the secondary battery 10 is a lithium ion battery.

  As shown in FIG. 3, the container 12 has a rectangular plate-like bottom portion 12a, a first side wall 12b erected from a pair of short side edges of the bottom portion 12a, and another pair of side edges of the bottom portion 12a. The second side wall 12c is erected from the long side edge of the first side wall 12b and is orthogonal to the first side walls 12b. The container 12 has an accommodation space S surrounded by a bottom portion 12a, a pair of first side walls 12b, and a pair of second side walls 12c on the inner side, and the container 12 has an insertion port communicating with the accommodation space S. 12d is open.

  The secondary battery 10 includes an electrode assembly 14 accommodated in the case 11, and a positive electrode terminal 51 and a negative electrode terminal 52 that are used to exchange power with the electrode assembly 14. The terminals 51 and 52 are attached to the case 11, specifically, the lid 13, and are spaced apart from both ends in the longitudinal direction of the lid 13.

  As shown in FIG. 2, the electrode assembly 14 is configured by alternately laminating a plurality of positive electrodes 21 as electrodes and a plurality of negative electrodes 22 as electrodes via separators 23. The positive electrode 21 includes a rectangular positive metal foil for positive electrode (in this embodiment, an aluminum foil) 21a and a rectangular positive electrode active material layer 21b provided on both surfaces (surfaces) of the positive electrode metal foil 21a. Have. The positive electrode 21 has a positive electrode-side uncoated portion 21d on which a positive electrode active material is not provided along one side 21c of the positive electrode metal foil 21a. And in the positive electrode 21, the positive electrode current collection tab 41 as a tab protrudes in a part of one side 21c of the positive electrode side uncoated part 21d.

  The negative electrode 22 includes a rectangular negative electrode metal foil (copper foil in this embodiment) 22a and a rectangular negative electrode active material layer 22b provided on both surfaces (surfaces) of the negative electrode metal foil 22a. Have. The negative electrode 22 has a negative electrode-side uncoated portion 22d where no negative electrode active material is provided along one side 22c of the negative electrode metal foil 22a. In the negative electrode 22, a negative electrode current collecting tab 42 as a tab is provided so as to protrude from a part of one side 22 c of the negative electrode side uncoated portion 22 d.

  As shown in FIG. 3, the positive electrode 21 and the negative electrode 22 are arranged such that the positive electrode current collecting tabs 41 are arranged in a line along the stacking direction of the electrode assembly 14 and do not overlap the positive electrode current collecting tabs 41. Thus, the negative electrode current collecting tabs 42 are stacked so as to be arranged in a row along the stacking direction of the electrode assemblies 14. In the following description, the direction in which all the positive electrode current collecting tabs 41 and the negative electrode current collecting tabs 42 are laminated is referred to as a lamination direction of the positive electrode tab group 43 and the negative electrode tab group 44. The electrode assembly 14 includes one end surface 36 in which one side 21 c of all the positive electrodes 21, one side 22 c of all the negative electrodes 22, and one side 23 a of the separator 23 are stacked. The positive electrode tab group 43 and the negative electrode tab group 44 are provided. The electrode assembly 14 is an end surface opposite to the one end surface 36, the bottom 12 a side of the container 12 is defined as the bottom end surface 33, and the surfaces positioned at both ends in the stacking direction of the electrode assembly 14 are the flat surfaces 31, 32. Further, a pair of surfaces orthogonal to both the flat surfaces 31 and 32 and the bottom side end surface 33 in the stacking direction of the electrode assembly 14 are defined as end surfaces 34 and 35.

  The positive electrode tab group 43 collects the positive electrode current collecting tabs 41 of all the positive electrode 21 close to one end within the range from one end to the other end in the stacking direction of the positive electrode tab group 43 and collects one end. It is folded back toward the other end side opposite to the side. The positive electrode current collecting tab 41 at one end in the stacking direction of the positive electrode tab group 43 is connected to a positive electrode conductive member 61 as a conductive member that transmits and receives electricity to the electrode assembly 14, and the positive electrode conductive member 61 has a positive electrode terminal. 51 is connected.

  As shown in FIG. 4, when the positive electrode conductive member 61 is resistance welded to the positive electrode tab group 43 and all the positive electrode current collecting tabs 41 are resistance welded, the positive electrode tab group 43 is disposed at one end in the stacking direction. The positive electrode conductive member 61 and the positive electrode welding plate 64 disposed at the other end in the stacking direction are sandwiched from both ends in the stacking direction. Then, the positive electrode conductive member 61, all the positive electrode current collecting tabs 41, and the positive electrode welding plate material 64 are welded by sandwiching the positive electrode conductive member 61 and the positive electrode welding plate member 64 with a resistance welder (not shown). The positive electrode conductive member 61 is connected to the positive electrode tab group 43.

  As shown in FIGS. 4 and 5, the positive electrode tab group 43 is formed with a positive electrode welded portion Y1 as a conductive portion over the entire stacking direction of the positive electrode tab group 43, and all positive electrodes are formed by the positive electrode welded portion Y1. The current collecting tab 41, the positive electrode conductive member 61, and the positive electrode welding plate member 64 are electrically connected. Further, the positive electrode tab group 43 and the positive electrode welding plate 64 are opposed to the one end face 36 of the electrode assembly 14 in a state of being separated in the protruding direction of the positive electrode current collecting tab 41.

  Note that, in all the positive electrode current collecting tabs 41, the front end side of the positive electrode welded portion Y <b> 1 is not joined to the positive electrode conductive member 61 and is a free end portion G. Note that the free end G of all the positive electrode current collecting tabs 41 is on the tip side of the positive electrode welded portion Y1, and the portion beyond the positive electrode weld plate 64 is the positive electrode with the edge of the positive electrode weld plate 64 as a fulcrum. The tab group 43 is folded back toward one end in the stacking direction. Therefore, in the positive electrode tab group 43, the free end G is in a state of being folded into two strips with the positive electrode welding plate material 64 interposed therebetween.

  As shown in FIG. 3, the positive electrode conductive member 61 has a crank shape, and a tab-side weld piece 61 a that is a portion on one side in the longitudinal direction with respect to the curved portion is joined to the positive electrode tab group 43. Further, in the positive electrode conductive member 61, the terminal-side joining piece 61b, which is the other side portion in the longitudinal direction with respect to the curved portion, is attached in a state where it is positioned closer to the one end face 36 of the electrode assembly 14 than the tab-side welding piece 61a. It has been.

  The negative electrode tab group 44 gathers the negative electrode current collecting tabs 42 of all the negative electrode electrodes 22 in the range from one end to the other end of the negative electrode tab group 44 in the stacking direction, It is folded back toward the other end side opposite to the side. The negative electrode tab group 44 is connected to a negative electrode conductive member 62 as a conductive member that exchanges electricity with the electrode assembly 14 by resistance welding, and a negative electrode terminal 52 is connected to the negative electrode conductive member 62.

  As shown in FIG. 5, when all the negative electrode current collecting tabs 42 are resistance welded while the negative electrode conductive member 62 is resistance welded to the negative electrode tab group 44, the negative electrode tab group 44 is disposed at one end in the stacking direction. The conductive member 62 and the negative electrode welding plate 65 disposed at the other end in the stacking direction are sandwiched from both ends in the stacking direction. Then, by sandwiching the negative electrode conductive member 62 and the negative electrode welding plate member 65 with a resistance welder (not shown), the negative electrode conductive member 62, all the negative electrode current collecting tabs 42, and the negative electrode welding plate member 65 are welded. The negative electrode conductive member 62 is connected to the negative electrode tab group 44.

  In the negative electrode tab group 44, a negative electrode welded portion Y2 as a conductive portion is formed over the entire lamination direction of the negative electrode tab group 44, and all the negative electrode current collecting tabs 42, the negative electrode conductive members 62, The negative electrode welding plate 65 is electrically connected. Further, the negative electrode tab group 44 and the negative electrode welding plate member 65 are opposed to the one end surface 36 of the electrode assembly 14 in a state of being separated in the protruding direction of the negative electrode current collecting tab 42.

  Note that, in all the negative electrode current collecting tabs 42, the front end side of the negative electrode welded portion Y <b> 2 is not joined to the negative electrode conductive member 62, and is a free end portion G. The free end G of all the negative electrode current collecting tabs 42 is on the tip side of the negative electrode welded portion Y2 and the portion beyond the negative electrode welding plate member 65 is a negative electrode tab group with the edge of the negative electrode welding plate member 65 as a fulcrum. 44 is folded toward one end side in the stacking direction. Therefore, in the negative electrode tab group 44, the free end G is in a state of being folded into two strips with the negative electrode welding plate member 65 interposed therebetween.

  As shown in FIG. 3, the negative electrode conductive member 62 has a crank shape, and a tab-side weld piece 62 a that is a portion on one side in the longitudinal direction with respect to the curved portion is joined to the negative electrode tab group 44. In addition, in the negative electrode conductive member 62, the terminal side joining piece 62b, which is the other side portion in the longitudinal direction with respect to the curved portion, is attached in a state where it is positioned closer to the one end face 36 of the electrode assembly 14 than the tab side welding piece 62a. It has been.

  As shown in FIG. 1, the positive terminal 51 and the negative terminal 52 pass through the lid 13 of the case 11 while being insulated by an insulating ring 63. In addition, the electrode assembly 14 is covered with a bottom-side end surface 33, both flat surfaces 31 and 32, and both end surfaces 34 and 35 by an insulating sheet 70 assembled in a square box shape. And between the bottom 12a of the container 12 and the bottom side end face 33 of the electrode assembly 14, between each first side wall 12b of the container 12 and the end faces 34, 35 of the electrode assembly 14, and each second of the container 12. The side wall 12c and the flat surfaces 31 and 32 of the electrode assembly 14 are insulated by insulating sheets 70, respectively.

  As shown in FIGS. 4 and 5, the insulating sheet 70 has a protruding portion 71 that protrudes from the one end surface 36 of the electrode assembly 14 in the protruding direction of the positive electrode current collecting tab 41 and the negative electrode current collecting tab 42. The protruding portion 71 has a frame shape as a whole. The positive electrode tab group 43 and the negative electrode tab group 44, the positive electrode conductive member 61, and the negative electrode conductive member 62 are disposed in a space surrounded by the protruding portion 71. That is, the protruding portion 71 is interposed between the tab groups 43 and 44 and the conductive members 61 and 62 and the inner surface of the case 11. Therefore, the tab groups 43 and 44 and the conductive members 61 and 62 and the container 12 are surrounded by the protruding portion 71 and insulated from the container 12.

  As shown in FIG. 1, the secondary battery 10 includes an attachment member 53 attached to the positive electrode tab group 43 and the negative electrode tab group 44. The attachment member 53 is made of an insulating resin and can be elastically deformed. The attachment member 53 has a rectangular shape extending in the longitudinal direction along each side 21c, 22c, 23a in the electrode assembly 14, and has a U-shaped cross section orthogonal to the longitudinal direction.

  As shown in FIGS. 3 and 4, the attachment member 53 includes tab-side weld pieces 61 a and 62 a of the positive electrode conductive member 61 and the negative electrode conductive member 62, and one end side (upper side) in the stacking direction of the tab groups 43 and 44. And a second covering portion 55 covering from the other end side (lower side) of the tab groups 43 and 44 in the stacking direction. Further, the attachment member 53 connects the first covering portion 54 and the second covering portion 55, and covers the tips of the current collecting tabs 41 and 42 and the tab side welding pieces 61a and 62a from the side. A portion 56 is provided. The attachment member 53 includes an accommodating portion 57 surrounded by the first covering portion 54, the second covering portion 55, and the third covering portion 56.

  The distance K between the opposing surfaces of the first covering portion 54 and the second covering portion 55 is the length in the stacking direction of the tab groups 43 and 44 folded in two strips, the thicknesses of the welding plate members 64 and 65, It is the same as the value which added the thickness of each tab side welding piece 61a, 62a of each electroconductive member 61,62, or has become a little short. And the 1st coating | coated part 54 and the 2nd coating | coated part 55 are tab side welding of all the free end parts G of the positive electrode current collection tab 41 folded in two strips on both sides of the board | plate material 64 for positive electrode welding. The piece 61a is clamped from both sides in the stacking direction. All of the free end G on the distal end side of the positive electrode weld Y1 and a part of the tab-side weld piece 61a are accommodated in the accommodating portion 57.

  Similarly, the first covering portion 54 and the second covering portion 55 are all free end portions G of the negative electrode current collecting tab 42 folded in two strips with the negative electrode welding plate member 65 interposed therebetween, and the tab side of the negative electrode conductive member 62. The weld piece 62a is clamped from both sides in the stacking direction. All of the free end G on the tip side of the negative electrode weld Y2 and a part of the tab-side weld piece 62a are accommodated in the accommodating portion 57.

  The first covering portion 54 of the attachment member 53 is sandwiched between the positive electrode conductive member 61 and the negative electrode conductive member 62 and the inner surface 13 a of the lid 13. The attachment member 53 insulates the positive electrode conductive member 61 and the negative electrode conductive member 62 from the lid 13 by the first covering portion 54. Further, the attachment member 53 integrates the positive electrode tab group 43 and the positive electrode conductive member 61 with the negative electrode tab group 44 and the negative electrode conductive member 62.

Next, the operation of the secondary battery 10 will be described.
In each tab group 43, 44, the distal end side of each welding tab Y 1, Y 2 of each current collecting tab 41, 42 is accommodated in the accommodating portion 57 of the attachment member 53. For this reason, the free ends G of the tab groups 43 and 44 are prevented from jumping out of the attachment member 53 along the stacking direction.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) The attachment member 53 is attached to the positive electrode tab group 43 and the negative electrode tab group 44, and the free ends G of the positive electrode current collection tab 41 and the negative electrode current collection tab 42 that are not joined to the conductive members 61 and 62 And accommodated in the accommodating portion 57 of the attachment member 53. For this reason, even if the secondary battery 10 vibrates, the first cover portion 54 and the second cover portion 55 cause the free end G, in particular, the portion folded from the welding plate members 64 and 65 to be attached to the attachment member 53. And the free end G can be prevented from coming into contact with the one end surface 36 of the electrode assembly 14 or the case 11. As a result, it is possible to prevent a short circuit between the tips of the current collecting tabs 41 and 42 and the electrode assembly 14.

  (2) The attachment member 53 is attached to the positive electrode tab group 43 and the negative electrode tab group 44, and the first covering portion 54 of the attachment member 53 is placed between the conductive members 61 and 62 and the inner surface 13 a of the lid 13. Arranged. For this reason, the conductive members 61 and 62 and the lid 13 can be insulated by the attachment member 53.

  (3) In the attachment member 53, the distance K between the opposing inner surfaces of the first covering portion 54 and the second covering portion 55 is set to the length in the stacking direction of the positive electrode tab group 43 and the negative electrode tab group 44 folded in two strips. In addition, the thickness is equal to or slightly shorter than the sum of the thicknesses of the welding plate members 64 and 65 and the thicknesses of the conductive members 61 and 62. The first cover 54 and the second cover 55 sandwich the positive electrode tab group 43, the positive electrode welding plate 64, and the positive electrode conductive member 61, and the negative electrode tab group 44, the negative electrode welding plate 65, and the negative electrode conductive member 62. Was pinched. Therefore, the first covering portion 54 and the second covering portion 55 can prevent the free end portions G of the current collecting tabs 41 and 42 from flapping in the stacking direction. As a result, the free end portions G of the current collecting tabs 41 and 42 can be prevented from sliding, and the generation of metal powder due to the sliding contact can be suppressed.

  (4) The tab groups 43 and 44 are gathered together at one end side in the stacking direction and folded back toward the other end side in the gathered state. The other end side in the stacking direction of each tab group 43, 44 faces the one end surface 36 of the electrode assembly 14. The 2nd coating | coated part 55 of the attachment member 53 has covered each tab group 43 and 44 from the lamination direction other end side. For this reason, even if the current collecting tabs 41 and 42 come into sliding contact with each other in the accommodating portion 57 and metal powder or the like is generated and falls, the metal powder or the like can be received by the second covering portion 55.

  (5) The secondary battery 10 includes an insulating sheet 70 that insulates the electrode assembly 14 from the case 11, and the insulating sheet 70 includes a protruding portion 71 that protrudes from one end surface 36 of the electrode assembly 14. And the part which is not covered with the attachment member 53 among each tab group 43 and 44 is insulated from the container 12 by the protrusion part 71. FIG. Therefore, the positive electrode tab group 43 and the negative electrode tab group 44 can be reliably insulated from the case 11 by the attachment member 53 and the insulating sheet 70.

  (6) The attachment member 53 was attached across the positive electrode tab group 43 and the negative electrode tab group 44. For this reason, the positive electrode tab group 43, the positive electrode welding plate material 64 and the positive electrode conductive member 61, and the negative electrode tab group 44, negative electrode welding plate material 65 and negative electrode conductive member 62 can be assembled together by the attachment member 53. Therefore, when the positive electrode terminal 51 and the negative electrode terminal 52 of the electrode assembly 14 are passed through the lid 13, the movement of the positive electrode conductive member 61 and the negative electrode conductive member 62 is restricted, and the penetrating work, and consequently the lid 13 with respect to the electrode assembly 14. The fastening work becomes easy.

  (7) The tip side of the positive electrode current collecting tab 41 and the negative electrode current collecting tab 42 was covered with the third covering portion 56 of the attachment member 53. For this reason, the third covering portion 56 protects the vicinity of the welded portions Y1 and Y2 of the tab groups 43 and 44, and can prevent foreign matters from being caught.

  (8) The 1st coating | coated part 54 of the attachment member 53 has also covered each welding part Y1, Y2. For this reason, when the secondary battery 10 vibrates, the load applied to each welded portion Y1, Y2 can be supported by the first covering portion 54, and the load applied to each welded portion Y1, Y2 can be reduced.

In addition, you may change the said embodiment as follows.
In the embodiment, the attachment member 53 is attached across the positive electrode tab group 43 and the positive electrode conductive member 61 and the negative electrode tab group 44 and the negative electrode conductive member 62. However, the attachment member 53 is divided into two, and the positive electrode tab One attachment member 53 may be attached to the group 43 and the positive electrode conductive member 61, and one attachment member 53 may be attached to the negative electrode tab group 44 and the negative electrode conductive member 62.

  As shown in FIG. 6, when the positive electrode current collecting tab 41 and the negative electrode current collecting tab 42 have different thicknesses, the attachment member 531 for the positive electrode tab group 43 and the attachment member 532 for the negative electrode tab group 44 are: What changed the distance K between the opposing surfaces of the 1st coating | coated part 54 and the 2nd coating | coated part 55 is prepared.

  The positive electrode tab group 43 and the negative electrode tab group 44 are gathered together within the range from one end to the other end in the stacking direction of each tab group 43, 44, and the other end side opposite to the one end side in the collected state However, it is not necessary to fold back. In this case, in the positive electrode tab group 43 and the negative electrode tab group 44, the tips of the current collecting tabs 41 and 42 are opposed to the inner surface 13 a of the lid 13. The attachment member 53 is attached from above the positive electrode tab group 43 and the negative electrode tab group 44 (on the lid 13 side).

  As shown in FIG. 7, the attachment member 58 may be formed by bending a resin plate. The attachment member 58 is integrally formed so that the first covering portion 54 and the third covering portion 56 are L-shaped, and the first covering portion 58 is formed at the boundary between the third covering portion 56 and the second covering portion 55. A bent portion 58a is provided. In addition, the attachment member 58 includes a fourth covering portion 59 at a position opposite to the boundary with the third covering portion 56 in the first covering portion 54, and the first covering portion 54 and the fourth covering portion are provided. A second bent portion 59 a is provided at the boundary with 59. The 4th coating | coated part 59 has coat | covered the lamination direction one end side of each tab group 43 and 44 from the side.

  In such a configuration, when the attachment member 58 is attached to the tab groups 43 and 44, the conductive members 61 and 62 are connected from the one end side in the stacking direction of the tab groups 43 and 44 by the first covering portion 54. In the covered state, the second covering portion 55 is bent from the first bent portion 58a. Then, the free ends G of the tabs 41 and 42 can be bent from the end edges of the welding plate members 64 and 65 while being pushed by the second covering portion 55. Therefore, by bending the second covering portion 55, the free end portion G can be folded and folded between the first covering portion 54 and the second covering portion 55, and the attachment work of the attachment member 58 is easy. become. Further, since the free end G is sandwiched, the second covering portion 55 does not slidably contact the free end G, and generation of metal powder accompanying the slidable contact is suppressed.

In addition, by bending the fourth covering portion 59 from the second bent portion 59 a, one end side in the stacking direction of each tab group 43, 44 can be covered and insulated from the container 12.
In the insulating sheet 70, the protruding portion 71 may not be provided, and the opening end of the insulating sheet 70 may be located on the same plane as the one end face 36 of the electrode assembly 14.

  In the attaching member 53, the distance K between the opposing inner surfaces of the first covering portion 54 and the second covering portion 55 is set to the length in the stacking direction of the tab groups 43, 44 and the welding plate members 64, 65. It is longer than the sum of the thickness and the thickness of each conductive member 61, 62, and each tab group 43, 44, each welding plate 64, 65, and each conductive member 61, 62 is sandwiched by the attachment member 53. It does not have to be.

  In the embodiment, when the respective tab groups 43 and 44 and the respective conductive members 61 and 62 are resistance-welded, the respective welding plate materials 64 and 65 are used, but the respective welding plate materials 64 and 65 are not used. The tab groups 43 and 44 and the conductive members 61 and 62 may be welded. In this case, the distance K between the opposing surfaces of the first covering portion 54 and the second covering portion 55 of the attachment member 53 is a distance obtained by removing the thickness of each of the welding plate members 64 and 65.

  In the embodiment, the free ends G of the current collecting tabs 41 and 42 are folded at the edges of the welding plates 64 and 65 and folded into two strips, but from the welds Y1 and Y2 to the tip. When the length of the free end portion G is short, the free end portion G does not have to be folded at the edge of each of the welding plate members 64 and 65.

  ○ As the conduction part, the positive electrode welded part Y1 and the negative electrode welded part Y2 are embodied, but the conductive member penetrating all the positive electrode current collecting tabs 41 or the negative electrode current collecting tabs 42 in the stacking direction of the tab groups 43 and 44 is conducted. It is good also as a part, and it is good also as a conduction | electrical_connection part by joining all the positive electrode current collection tabs 41 or the negative electrode current collection tabs 42 by methods other than resistance welding.

  In the embodiment, the positive electrode 21 has the positive electrode active material layer 21b on both sides of the positive electrode metal foil 21a, but has the positive electrode active material layer 21b only on one side of the positive electrode metal foil 21a. Also good. Similarly, the negative electrode 22 has the negative electrode active material layer 22b on both sides of the negative electrode metal foil 22a, but may have the negative electrode active material layer 22b only on one side of the negative electrode metal foil 22a. .

The power storage device may be another power storage device such as an electric double layer capacitor.
In embodiment, although the secondary battery 10 was a lithium ion secondary battery, it is not restricted to this, Other secondary batteries, such as nickel hydride, may be sufficient. 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.

  Y1... Positive electrode welded portion as conducting portion, Y2... Negative electrode welded portion as conducting portion, 10... Secondary battery as power storage device, 11... Case, 14 ... electrode assembly, 21 ... positive electrode, 21c. ... Negative electrode, 22c ... One side, 36 ... One end face, 41 ... Positive electrode current collecting tab, 42 ... Negative electrode current collecting tab, 43 ... Positive electrode tab group, 44 ... Negative electrode tab group, 53 (531, 532), 58 ... Attachment 54, 1st coating | coated part, 55 ... 2nd coating | coated part, 56 ... 3rd coating | coated part, 57 ... accommodating part, 61 ... Positive electrode conductive member, 62 ... Negative electrode conductive member, 70 ... Insulating sheet, 71 ... Overhang | projection part.

Claims (4)

Provided in the case with an electrode assembly laminated with electrodes of different poles insulated,
A tab projecting from one side of the electrode to extract electricity from the electrode;
In the electrode assembly, on one end surface where one side of the electrode is gathered, a tab group in which the tabs are gathered together in the stacking direction of the electrode assembly is provided.
A power storage device comprising a conductive member joined to a tab at one end in the stacking direction of the tab group, with all tabs of the tab group being conducted at a conducting portion,
The tab group is a first folded portion in which the tab in a state gathered to one end side in the stacking direction of the tab group is folded toward the other end side opposite to the one end side;
A first extending portion that extends from the first folded portion along the stacking direction of the electrode assembly, and in which the conducting portion is located;
A second folded portion that is continuous with the first extending portion and folded toward the one end side;
A second extending portion extending from the second folded portion in the stacking direction of the electrode assembly ,
It comprises an attachment member made of an insulating material attached to the tab group,
The attachment member includes a first covering portion that covers the conductive member from one end side in the stacking direction of the tab group at least on the tip end side of the tab from the conduction portion in the first extending portion;
A second covering portion covering the second extending portion from the other end side in the stacking direction of the tab group;
A third covering portion that connects the first covering portion and the second covering portion and covers the second folded portion, and
All the tabs surrounded by the first covering portion, the second covering portion, and the third covering portion, at least on the distal end side than the conducting portion, and the conductive member overlapping in the stacking direction of the tab group; A power storage device including a storage portion that stores the battery.   2. The power storage according to claim 1, wherein the first covering portion and the second covering portion sandwich all of the tabs and the conductive member overlapping in the stacking direction of the tab group on the tip side of the conducting portion. apparatus. An insulating sheet that insulates the electrode assembly from the case is provided, and the insulating sheet includes a protruding portion that protrudes from the one end surface along the protruding direction of the tab from the one end surface of the electrode assembly. The power storage device according to claim 1 or 2 . The power storage device according to any one of claims 1 to 3 , wherein the power storage device is a secondary battery.