JP2018073630A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device that can suppress deformation of an electrode assembly due to pressing force generated when storing the electrode assembly into a case main body.SOLUTION: An electrode assembly 12 has a positive electrode tab group 30 having a positive electrode current collection tab 28 protruding from one side of a positive electrode laminated thereon. Lid terminal members 14 are constituted by integrating a lid 15 for closing an opening part 13a of a box-like case main body 13 with a bottom for storing the electrode assembly 12, a positive electrode terminal 16, fixed to the lid 15, which transfers electricity to the electrode assembly 12, and a positive electrode conducting member 18 electrically connecting the positive electrode tab group 30 with the positive electrode terminal 16. The electrode assembly 12 has a first covered part 12g covered with a first seal 32 on a tab side end surface 12a having the positive electrode tab group 30. A dimension of the first covered part 12g in a laminate direction of the electrode assembly 12 is smaller than a dimension in the laminate direction of a part which is not covered with the first seal 32 of the electrode assembly 12.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage device in which a lid terminal member and an electrode assembly are integrated via an uncoated portion group of electrodes.

  Conventionally, vehicles such as EVs (Electric Vehicles) and PHVs (Plug in Hybrid Vehicles) have been mounted with lithium-ion secondary batteries or nickel-hydrogen secondary batteries as power storage devices that store power supplied to electric motors and the like. . For example, as disclosed in Patent Document 1, 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 through a separator, and a rectangular parallelepiped case that accommodates the electrode assembly And. Some cases have a bottomed square box-like case body having an opening for inserting an electrode assembly, and a rectangular plate-like lid for closing the opening of the case body. The case accommodates the electrode assembly in a state where the stacking direction of the positive electrode and the negative electrode is along the short direction of the case. Further, a tab (uncoated part) is projected from one side of the positive electrode and the negative electrode, and a conductive member for each electrode is joined to a tab group (uncoated part group) in which tabs are stacked. Furthermore, electrode terminals of each pole are electrically connected to each conductive member.

  In one of the secondary battery assembly methods, the electrode assembly and the lid are integrated in advance, the electrode assembly previously integrated with the lid is inserted into the case body, and then the lid is attached to the case. There is a method of welding to the main body. To integrate the electrode assembly and the lid, first connect conductive members of the same polarity to the positive and negative electrode tab groups of the electrode assembly, and after connecting the electrode terminals of the same polarity to the conductive members of each electrode, Part of each electrode terminal is inserted through two insertion holes formed in the lid. Then, a nut is screwed into the electrode terminal protruding from the lid, and the electrode terminal is fixed to the lid. Then, the electrode assembly integrated with the electrode terminal via the conductive member is also integrated with the lid.

JP 2012-119183 A

  By the way, the secondary battery is designed so that the volume of the electrode assembly is as large as possible in order to increase the capacity as much as possible. In order to increase the volume of the electrode assembly, in the depth direction of the case, the bottom end surface of the electrode assembly is made as large as possible so as to approach the inner bottom surface of the case body.

  Further, with respect to the short direction of the case, the electrode assembly is enlarged as much as possible so that both end surfaces in the stacking direction of the positive electrode and the negative electrode are close to the inner wall surface of the case facing each end surface. . Similarly, with respect to the longitudinal direction of the case, the electrode assembly can have both end surfaces in the width direction in the direction along the bottom end surfaces of the positive electrode and the negative electrode approach the inner wall surface of the case facing each end surface. It is as large as possible.

  In such a secondary battery, at the time of manufacture, the electrode assembly is accommodated with the bottom side end face approaching the inner bottom face of the case. However, since the clearance between the end surface in the stacking direction and the width direction of the electrode assembly and the inner wall surface of the case is small, the electrode assembly is attached to the case body to bring the bottom end surface of the electrode assembly closer to the inner bottom surface of the case. It is necessary to push inward. When the electrode assembly and the lid are integrated in advance as described above, the lid is pressed toward the electrode assembly, and the electrode assembly is pushed into the case body through the lid. Here, in the case where the negative electrode and the separator are slightly larger than the positive electrode, in the electrode assembly in which the positive electrode and the negative electrode are stacked in layers via the separator, the tab side end surface is the edge of the negative electrode. And an edge of the separator. Accordingly, the rigidity of the tab-side end surface of the electrode assembly is low, and when the electrode body is pushed through the lid, the edge of the negative electrode and the edge of the separator are crushed and deformed by the pressing force received from the lid.

  The present invention has been made paying attention to such problems existing in the prior art, and its purpose is to prevent the electrode assembly from being deformed by a pressing force when the electrode assembly is accommodated in the case body. An object is to provide a power storage device that can be suppressed.

  The power storage device for solving the above problems is laminated in a state where the positive electrode and the negative electrode are insulated from each other by a separator, and an uncoated portion having a shape protruding from one side of the positive electrode and the negative electrode An electrode assembly having a group of uncoated portions stacked, a bottomed box-shaped case body having an opening for accommodating the electrode assembly, and a lid for closing the opening of the case body; An electrode terminal fixed to the lid, for transferring electricity with the electrode assembly, and a lid terminal member integrated with a conductive member electrically connecting the uncoated portion group and the electrode terminal; The electrode assembly includes an end surface having the uncoated portion group, and has a covering portion covered with a covering member on the end surface, in the stacking direction of the positive electrode, the negative electrode, and the separator. Dimensions of the covering part It is summarized in that less than the dimension of the the stacking direction of the not covered by the covering member portion of the electrode assembly.

  According to this, since the lid terminal member and the electrode assembly are in a state of being integrated through the uncoated portion group, the electrode assembly is moved to the case body by pressing the lid toward the case body. It can be stored in the body. At this time, a part of the lid terminal member presses the electrode assembly. The dimension of the covering portion in the stacking direction of the electrode assembly is smaller than the dimension in the stacking direction of the portion not covered with the covering member in the electrode assembly. For this reason, the dimension in the laminating direction is reduced by forming the covering portion, the rigidity is increased in the portion where the electrodes and the separator are gathered together, and it is difficult to be crushed even when pressed by a part of the lid terminal member. Therefore, deformation of the electrode assembly due to the pressing force when the electrode assembly is housed in the case body can be suppressed.

Moreover, about an electrical storage apparatus, it is preferable that the said cover terminal member has a press part which presses the said end surface, when accommodating the said electrode assembly in the said case main body.
According to this, the end surface of the electrode assembly can be pressed by the pressing portion of the lid terminal member by pressing the lid toward the case body, and the electrode assembly can be accommodated in the case body.

Moreover, it is preferable that the dimension of the said coating | coated part to the said lamination direction is smaller than the dimension of the said press part to the said lamination direction about an electrical storage apparatus.
According to this, when the part whose dimension in the laminating direction is reduced by forming the covering portion is pressed by a part of the lid terminal member, the electrode and separator constituting the end surface having the uncoated portion group It is pressed by the lid terminal member. Therefore, the deformation of the electrode assembly due to the pressing force when the electrode assembly is accommodated in the case body can be further suppressed.

Moreover, it is preferable that the said press part is located in the position facing the said coating | coated member about an electrical storage apparatus.
According to this, when the electrode assembly is accommodated in the case main body, the pressing portion contacts the covering member, so that the pressing portion constitutes an end surface having an uncoated portion group and is covered by the covering member. Press the electrode and separator. Therefore, deformation of the electrode assembly due to the pressing force when the electrode assembly is housed in the case body can be suppressed. Moreover, since a coating | coated part is protected by a coating | coated member, it can suppress that a coating | coated part is damaged by the press by a press part.

Moreover, about an electrical storage apparatus, it is preferable that the said press part is the said electrically-conductive member.
According to this, since it is not necessary to provide a press part separately, the structure of a cover terminal member can be simplified.

  ADVANTAGE OF THE INVENTION According to this invention, a deformation | transformation of the electrode assembly by the pressing force at the time of accommodating an electrode assembly in a case main body can be suppressed.

The disassembled perspective view of the secondary battery of embodiment. The perspective view which shows the external appearance of a secondary battery. The disassembled perspective view which shows the component of an electrode assembly. (A) is a schematic sectional drawing of the secondary battery before accommodating an electrode assembly in a case main body, (b) is a schematic sectional drawing of the secondary battery after accommodating an electrode assembly in a case main body. (A) is a schematic sectional drawing of the secondary battery before accommodating an electrode assembly in a case main body, (b) is a schematic sectional drawing of the secondary battery after accommodating an electrode assembly in a case main body. The perspective view of the electrode assembly of another example.

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 FIGS. 1 and 2, a secondary battery 10 as a power storage device includes a rectangular parallelepiped case 11, and an electrode assembly 12 is accommodated in the case 11. The secondary battery 10 of this embodiment is a lithium ion secondary battery.

  The case 11 includes a case main body 13 made of a metal having a bottomed rectangular tube shape (for example, aluminum or aluminum alloy), and a lid 15 as a part of the lid terminal member 14 that closes the opening 13 a of the case main body 13. Have. An electrolyte (electrolytic solution) (not shown) is accommodated in the case 11. The case main body 13 includes an inner bottom surface 13b and first to fourth inner wall surfaces 13c to 13f connected to the inner bottom surface 13b (see FIGS. 4B and 5B). The case body 13 includes a first inner wall surface 13c on one inner wall surface of the inner wall surfaces connected to the pair of long edge portions of the inner bottom surface 13b, and a second inner wall surface facing the first inner wall surface 13c. A wall surface 13d is provided. In addition, the case body 13 includes a third inner wall surface 13e on one inner wall surface of the inner wall surfaces that connects the first inner wall surface 13c and the second inner wall surface 13d and is connected to the pair of short edges of the inner bottom surface 13b. The other inner wall surface facing the third inner wall surface 13e is provided with a fourth inner wall surface 13f.

  As shown in FIG. 3, the electrode assembly 12 includes a sheet-like positive electrode 20 and a sheet-like negative electrode 21 as electrodes having different polarities. The electrode assembly 12 is a laminate having a layered structure in which a separator 26 of a microporous film is interposed between the positive electrode 20 and the negative electrode 21. The electrode assembly 12 is configured by alternately stacking a plurality of positive electrodes 20 and a plurality of negative electrodes 21. That is, the electrode assembly 12 includes a plurality of sets each including a positive electrode 20, a negative electrode 21, and a separator 26. The direction in which the positive electrode 20 and the negative electrode 21 are stacked is defined as the stacking direction of the electrode assembly 12.

  The positive electrode 20 includes a rectangular sheet-like positive electrode metal foil (for example, an aluminum foil) 22 and a positive electrode active material layer 23 containing a positive electrode active material on both surfaces of the positive electrode metal foil 22. The positive electrode 20 includes a first edge 20a on one edge of the pair of long sides, and a second edge 20b on the other edge that is the opposite side of the first edge 20a. . The positive electrode 20 includes a third edge 20c on one edge of a pair of short edges connecting the first edge 20a and the second edge 20b, and the third edge 20c. A fourth edge portion 20d is provided on the other edge portion which is the opposite side. The positive electrode 20 has a positive electrode current collecting tab 28 as an uncoated portion having a shape protruding from the first edge portion 20a. The positive electrode current collecting tab 28 is a portion constituted by the positive electrode metal foil 22 itself without being coated with the positive electrode active material layer 23 in the positive electrode metal foil 22.

  The negative electrode 21 has a rectangular sheet-like negative electrode metal foil (for example, copper foil) 24 and a negative electrode active material layer 25 containing a negative electrode active material on both surfaces of the negative electrode metal foil 24. The negative electrode 21 includes a first edge 21a on one edge of the pair of long sides, and a second edge 21b on the other edge that is the opposite side of the first edge 21a. . The negative electrode 21 includes a third edge 21c on one edge of the pair of short edges connecting the first edge 21a and the second edge 21b, and the third edge 21c. A fourth edge portion 21d is provided on the other edge portion which is the opposite side. The negative electrode 21 has a negative electrode current collecting tab 29 as an uncoated part protruding from the first edge 21a. The negative electrode current collecting tab 29 is a portion constituted by the negative electrode metal foil 24 itself without being coated with the negative electrode active material layer 25 in the negative electrode metal foil 24.

  The length of the first edge 21a of the negative electrode 21 is longer than the length of the first edge 20a of the positive electrode 20, and the length of the second edge 21b of the negative electrode 21 is the second edge 20b of the positive electrode 20. Longer than Further, the length of the third edge 21 c of the negative electrode 21 is longer than the length of the third edge 20 c of the positive electrode 20, and the length of the fourth edge 21 d of the negative electrode 21 is the fourth length of the positive electrode 20. It is longer than the length of the edge 20d. Therefore, the negative electrode 21 is slightly larger than the positive electrode 20.

  The separator 26 is made of a rectangular sheet-like insulating material. The separator 26 insulates the positive electrode 20 and the negative electrode 21. The separator 26 includes a first edge portion 26a at one edge portion of the edge portions along the pair of long sides, and a second edge portion 26b at the other edge portion that is the opposite side of the first edge portion 26a. The separator 26 includes a third edge 26c on one edge of the pair of short edges connecting the first edge 26a and the second edge 26b, and the third edge 26c. A fourth edge 26d is provided on the other edge that is the opposite side.

  The length of the first edge portion 26 a of the separator 26 is equal to the length of the first edge portion 21 a of the negative electrode 21, and the length of the second edge portion 26 b of the separator 26 is the length of the second edge portion 21 b of the negative electrode 21. Equal to length. Further, the length of the third edge 26 c of the separator 26 is equal to the length of the third edge 21 c of the negative electrode 21, and the length of the fourth edge 26 d of the separator 26 is the fourth edge of the negative electrode 21. It is equal to the length of 21d. Therefore, the separator 26 is slightly larger than the positive electrode 20 and has the same size as the negative electrode 21.

  In the positive electrode 20, the positive electrode current collecting tabs 28 are stacked in a row along the stacking direction. The positive electrode 20 includes a positive electrode tab group 30 that is bent in a state in which each positive electrode current collecting tab 28 is collected (bundled) within a range from one end to the other end in the stacking direction of the electrode assembly 12. The positive electrode tab group 30 is electrically connected by welding locations where the positive electrode current collecting tabs 28 overlap.

  In the negative electrode 21, the negative electrode current collecting tabs 29 are stacked in a line along the stacking direction at a position not overlapping the positive electrode current collecting tab 28. The negative electrode 21 has a negative electrode tab group 31 that is bent in a state in which the respective negative electrode current collecting tabs 29 are collected (bundled) within a range from one end to the other end in the stacking direction of the electrode assembly 12. The negative electrode tab group 31 is electrically connected by welding a portion where the negative electrode current collecting tabs 29 are overlapped.

  As shown in FIG. 1, the electrode assembly 12 includes a tab-side end surface 12 a on an end surface facing the lid 15, and a positive electrode tab group 30 and a negative electrode tab group 31 serving as an uncoated portion group on the tab-side end surface 12 a. Is provided. The tab side end surface 12 a is configured by the first edge portion 21 a of the negative electrode 21 and the first edge portion 26 a of the separator 26. The electrode assembly 12 includes a bottom-side end surface 12b on an end surface facing the inner bottom surface 13b of the case body 13. The bottom-side end surface 12 b is configured by the second edge portion 21 b of the negative electrode 21 and the second edge portion 26 b of the separator 26.

  In addition, the electrode assembly 12 includes a first end surface 12 c on an end surface of the case body 13 that faces the first inner wall surface 13 c. The first end face 12c is constituted by, for example, the negative electrode 21. The electrode assembly 12 includes a second end surface 12d on the end surface of the case body 13 facing the second inner wall surface 13d. The second end face 12d is constituted by, for example, the negative electrode 21. The electrode assembly 12 includes a third end surface 12e on an end surface of the case body 13 that faces the third inner wall surface 13e. The third end face 12e is configured by laminating the third edge 21c of the negative electrode 21 and the third edge 26c of the separator 26. The electrode assembly 12 includes a fourth end surface 12f on the end surface of the case body 13 facing the fourth inner wall surface 13f. The fourth end surface 12 f is configured by the fourth edge portion 21 d of the negative electrode 21 and the fourth edge portion 26 d of the separator 26.

  As shown in FIGS. 1 and 4, a first tape 32 and a second tape 33 as covering members are attached to the electrode assembly 12. In the electrode assembly 12, the direction in which the positive electrode tab group 30 and the negative electrode tab group 31 are arranged is the width direction, and the direction in which a straight line connecting the tab side end surface 12a and the bottom side end surface 12b is the shortest distance is the height direction. .

  The first tape 32 is attached so as to cover the first covering portion 12g as a covering portion positioned on the outer side in the width direction from the positive electrode current collecting tab 28 on the tab side end surface 12a of the electrode assembly 12. The first covering portion 12g is located in a portion sandwiched between the positive electrode tab group 30 and the third end surface 12e in the width direction of the electrode assembly 12. Further, the first covering portion 12 g is constituted by the first edge portion 21 a of the negative electrode 21 and the first edge portion 26 a of the separator 26. This is because the negative electrode 21 and the separator 26 of the present embodiment are slightly larger than the positive electrode 20, and the first edge 21 a of the negative electrode 21 and the first edge 26 a of the separator 26 are the first edge of the positive electrode 20. This is because it protrudes from 20a.

  The first tape 32 is rectangular. One end of the first tape 32 in the longitudinal direction, which is the direction along the stacking direction, is attached to the upper side in the height direction of the first end surface 12c of the electrode assembly 12, and the other end in the longitudinal direction of the first tape 32 is The electrode assembly 12 is attached to the upper side in the height direction of the second end face 12d.

  The 2nd tape 33 is stuck so that the 2nd covering part 12h as a covering part located in the width direction outside from negative electrode current collection tab 29 in tab side end face 12a of electrode assembly 12 may be covered. The second covering portion 12 h is located in a portion sandwiched between the negative electrode tab group 31 and the fourth end surface 12 f in the width direction of the electrode assembly 12. The second covering portion 12 h is configured by the first edge portion 21 a of the negative electrode 21 and the first edge portion 26 a of the separator 26. This is because the negative electrode 21 and the separator 26 of the present embodiment are slightly larger than the positive electrode 20, and the first edge 21 a of the negative electrode 21 and the first edge 26 a of the separator 26 are the first edge of the positive electrode 20. This is because it protrudes from 20a.

  The second tape 33 is rectangular. One end of the second tape 33 in the longitudinal direction, which is the direction along the stacking direction, is attached to the upper side in the height direction of the first end surface 12c of the electrode assembly 12, and the other end in the longitudinal direction of the second tape 33 is The electrode assembly 12 is attached to the upper side in the height direction of the second end face 12d.

  The first tape 32 is stuck in a state in which the first covering portion 12g is constrained in the stacking direction so that the width direction one end side and the height direction upper side portion of the electrode assembly 12 are converged into a tapered shape. ing. The second tape 33 is attached in a state in which the second covering portion 12h is constrained in the stacking direction so that the other end in the width direction and the upper portion in the height direction of the electrode assembly 12 are converged into a tapered shape. Has been.

  In the present embodiment, a rectangular third tape 34 is attached so as to cover one end side in the width direction of the bottom end face 12b of the electrode assembly 12, and the width direction etc. on the bottom end face 12b of the electrode assembly 12 A rectangular fourth tape 35 is attached so as to cover the end side. One end of the third tape 34 and the fourth tape 35 in the longitudinal direction, which is the direction along the stacking direction, is attached to the lower side in the height direction of the first end surface 12 c of the electrode assembly 12. The other ends of the third tape 34 and the fourth tape 35 in the longitudinal direction are attached to the lower side in the height direction of the second end surface 12 d of the electrode assembly 12. However, the dimension in the stacking direction of the portion where the third tape 34 and the fourth tape 35 are attached is the same as the portion where the first to fourth tapes 32 to 35 are not attached. By sticking the first to fourth tapes 32 to 35 to the electrode assembly 12, the stacking deviation of the positive electrode 20, the negative electrode 21, and the separator 26 can be suppressed.

  The dimension in the width direction of the electrode assembly 12 is slightly smaller than the opening width in the longitudinal direction of the case body 13. Therefore, in a state where the electrode assembly 12 is accommodated in the case main body 13, it is between the third end surface 12e of the electrode assembly 12 and the third inner wall surface 13e of the case main body 13, and the fourth end surface 12f and the case main body. There is only a slight clearance between the 13th fourth inner wall surfaces 13f. The bottom end surface 12 b of the electrode assembly 12 is in contact with the inner bottom surface 13 b of the case body 13.

  On the other hand, the dimension of the electrode assembly 12 in the stacking direction is different between a portion restricted by the first tape 32 and the second tape 33 and a portion not restricted. In addition, the part which is not restrained contains the part to which the 3rd tape 34 and the 4th tape 35 are stuck. The dimension of the electrode assembly 12 constrained by the first tape 32 and the second tape 33, that is, the tab-side end surface 12 a in the stacking direction is smaller than the opening width of the case body 13 in the short direction. On the other hand, the dimension in the stacking direction of the portion of the electrode assembly 12 that is not constrained by the first tape 32 and the second tape 33 is slightly smaller than the opening width of the case body 13 in the short direction. For this reason, there is sufficient clearance between the width direction both ends of the first end surface 12c of the electrode assembly 12 and the height direction upper portion and the first inner wall surface 13c of the case body 13, but other portions There is only a slight clearance between the first inner wall surface 13c and the first inner wall surface 13c. In addition, there is sufficient clearance between the width direction both ends of the second end surface 12d of the electrode assembly 12 and the height direction upper side portion and the second inner wall surface 13d of the case body 13; There is only a slight clearance between the case body 13 and the second inner wall surface 13d.

  As shown in FIGS. 4 and 5, the secondary battery 10 has a lid terminal member 14. The lid terminal member 14 is a conductive member electrically connected to the lid 15, the positive electrode terminal 16 and the negative electrode terminal 17 as electrode terminals that exchange electricity with the electrode assembly 12, and the positive electrode terminal 16 or the negative electrode terminal 17. It is composed of a positive electrode conductive member 18 and a negative electrode conductive member 19. The lid terminal member 14 and the electrode assembly 12 are integrated via a positive electrode tab group 30 and a negative electrode tab group 31.

  The positive electrode terminal 16 is fixed to the lid 15 so as to protrude to the outside of the case 11 as a positive electrode terminal. The positive electrode terminal 16 has a male screw 16 a at an end portion of the positive electrode terminal 16 that protrudes to the outside of the case 11, and a nut 40 is screwed to the male screw. The positive electrode terminal 16 is fastened to the lid 15 with the lid 15 sandwiched between the inner end portion 16 b of the positive electrode terminal 16 protruding inside the case 11 and the nut 40. The positive electrode terminal 16 is electrically connected to the positive electrode tab group 30 of the electrode assembly 12 through a plate-like positive electrode conductive member 18 made of metal (for example, aluminum).

  The positive electrode conductive member 18 includes a first joint portion 18 a as a pressing portion disposed between the electrode assembly 12 and the inner end portion 16 b of the positive electrode terminal 16, and the electrode assembly 12 and the inner surface 15 a of the lid 15. And a second joint 18b disposed therebetween. The first joint 18 a has an end surface near the lid 15 joined to the inner end 16 b of the positive electrode terminal 16, and the second joint 18 b has an end surface near the electrode assembly 12 joined to the positive electrode tab group 30.

  The height dimension of the first joint portion 18a is smaller than the thickness that is the dimension in the height direction of the positive electrode tab group 30 that is bundled and bent in the electrode assembly 12 before being housed in the case body 13 (see FIG. 4 (a)). Moreover, the dimension of the 1st junction part 18a in the lamination direction is larger than the dimension of the 1st coating | coated part 12g in the lamination direction (refer Fig.5 (a) and FIG.5 (b)).

  The negative electrode terminal 17 is fixed to the lid 15 so as to protrude outside the case 11 as a negative electrode terminal. The negative electrode terminal 17 has a male screw 17a at an end portion of the negative electrode terminal 17 protruding to the outside of the case 11, and a nut 50 is screwed into the male screw 17a. The negative electrode terminal 17 is fastened to the lid 15 in a state where the lid 15 is sandwiched between the inner end portion 17 b of the negative electrode terminal 17 protruding inside the case 11 and the nut 50. The negative electrode terminal 17 is electrically connected to the negative electrode tab group 31 of the electrode assembly 12 through a plate-like negative electrode conductive member 19 made of metal (for example, copper).

  The negative electrode conductive member 19 includes a first joint portion 19 a as a pressing portion disposed between the electrode assembly 12 and the inner end portion 17 b of the negative electrode terminal 17, and the electrode assembly 12 and the inner surface 15 a of the lid 15. And a second joint portion 19b disposed therebetween. The end surface near the lid 15 of the first joint portion 19 a is joined to the inner end portion 17 b of the negative electrode terminal 17, and the end surface near the electrode assembly 12 of the second joint portion 19 b is joined to the negative electrode tab group 31.

  The dimension in the height direction of the first joint portion 19a is smaller than the thickness that is the dimension in the height direction of the negative electrode tab group 31 that is bundled and bent in the electrode assembly 12 before being accommodated in the case body 13 (FIG. 4 (a)). Moreover, the dimension of the 1st junction part 19a in the lamination direction is larger than the dimension of the 2nd coating | coated part 12h in the lamination direction (refer Fig.5 (a) and FIG.5 (b)).

  In order to insulate the electrode assembly 12 from the case body 13, the bottom end face 12 b and the first to fourth end faces 12 c to 12 f of the electrode assembly 12 are covered with an insulating sheet (not shown) or the like. . Moreover, when the 1st tape 32 and the 2nd tape 33 are not the material which has insulation, the 1st tape 32 and the 2nd tape 33 are also covered with an insulating sheet. In addition, various insulating members (not shown) are attached to the lid terminal member 14 in order to insulate the lid 15 from the positive electrode terminal 16, the negative electrode terminal 17, the positive electrode conductive member 18, and the negative electrode conductive member 19. .

Next, a process of housing the electrode assembly 12 in the case body 13 will be described.
As shown in FIGS. 4A and 5A, the electrode assembly 12 before being accommodated in the case body 13 is integrated with the lid 15. As described above, since the height dimension of the first joint portion 18a of the positive electrode conductive member 18 is smaller than the thickness of the positive electrode tab group 30 bundled and bent in the electrode assembly 12, the first joint portion 18a and the electrode It is spaced apart from the tab side end surface 12a of the assembly 12 in the height direction. Similarly, since the dimension in the height direction of the first joint portion 19a of the negative electrode conductive member 19 is smaller than the thickness of the negative electrode tab group 31 bundled and bent in the electrode assembly 12, the first joint portion 19a and the electrode assembly. 12 tab side end surfaces 12a are spaced apart in the height direction.

  Then, with the electrode assembly 12 integrated with the lid 15 disposed in the opening 13 a of the case body 13, the lid 15 is pressed downward in the height direction. At this time, the positive electrode terminal 16 fixed to the lid 15 presses the positive electrode conductive member 18 downward in the height direction. Of the positive electrode conductive member 18 pressed by the positive electrode terminal 16, the second joint 18b presses the positive electrode tab group 30 downward in the height direction. The positive electrode tab group 30 pressed by the second joint 18b absorbs the pressing force by being crushed (see FIGS. 4B and 5B).

  The negative terminal 17 fixed to the lid 15 presses the negative electrode conductive member 19 downward in the height direction. Of the negative electrode conductive member 19 pressed by the negative electrode terminal 17, the second joint portion 19b presses the negative electrode tab group 31 downward in the height direction. The negative electrode tab group 31 pressed by the second joint portion 19b absorbs the pressing force by being crushed (see FIGS. 4B and 5B).

  When the cover 15 is continuously pressed, the positive electrode tab group 30 is crushed and absorbs the pressing force from the second joint portion 18b of the positive electrode conductive member 18, and the first joint portion 18a is adhered to the electrode assembly 12. Abuts on the first tape 32. Similarly, while the negative electrode tab group 31 is crushed, it absorbs the pressing force from the second joint portion 19 b of the negative electrode conductive member 19, and the first joint portion 19 a is attached to the second tape 33 attached to the electrode assembly 12. Abut.

  Further, when the lid 15 is continuously pressed, the first joint portion 18a of the positive electrode conductive member 18 lowers the first covering portion 12g on the tab side end surface 12a of the electrode assembly 12 via the first tape 32 in the height direction lower side. The second joint portion 18b presses the tab side end face 12a of the electrode assembly 12 downward in the height direction via the positive electrode tab group 30. The first joint portion 19a of the negative electrode conductive member 19 presses the second covering portion 12h on the tab side end surface 12a of the electrode assembly 12 via the second tape 33 toward the lower side in the height direction. The joint portion 19b presses the tab side end surface 12a of the electrode assembly 12 through the negative electrode tab group 31 downward in the height direction. The electrode assembly 12 pressed by the positive electrode conductive member 18 and the negative electrode conductive member 19 moves downward in the height direction, that is, toward the inner bottom surface 13 b of the case body 13.

  In this way, the downward pressure in the height direction with respect to the lid 15 is applied via the lid 15, the positive electrode terminal 16 or the negative electrode terminal 17, the positive electrode conductive member 18 or the negative electrode conductive member 19, the first tape 32 or the second tape 33. It is added to the tab side end surface 12 a of the electrode assembly 12. When the bottom end surface 12b of the electrode assembly 12 contacts the inner bottom surface 13b of the case main body 13 and the electrode assembly 12 is accommodated in the case main body 13, the pressing of the lid 15 is finished.

Next, the operation of the secondary battery 10 will be described.
The width direction one end side and the height direction upper side part of the electrode assembly 12 are restrained by the 1st tape 32 in the lamination direction. And the dimension of the lamination direction of the width direction one end side in the tab side end surface 12a of the electrode assembly 12 is smaller than the dimension of the 1st junction part 18a of the positive electrode conductive member 18 in the lamination direction. Therefore, when the 1st junction part 18a presses the 1st coating | coated part 12g of the tab side end surface 12a of the electrode assembly 12 via the 1st tape 32, the lamination | stacking of the 1st coating | coated part 12g converged to the constriction. The whole direction is pressed.

  Similarly, the other end in the width direction and the upper side in the height direction of the electrode assembly 12 are restrained in the stacking direction by the second tape 33. And the dimension of the lamination direction of the width direction other end side in the tab side end surface 12a of the electrode assembly 12 is smaller than the dimension of the lamination direction of the 1st junction part 19a of the negative electrode conductive member 19. FIG. Therefore, when the 1st junction part 19a presses the 2nd coating | coated part 12h of the tab side end surface 12a of the electrode assembly 12 via the 2nd tape 33, the lamination | stacking of the 2nd coating | coated part 12h converged to the constriction. The whole direction is pressed. That is, the negative electrode 21 and the separator 26 are pressed by the first joint portions 18 a and 19 a of the positive electrode conductive member 18 and the negative electrode conductive member 19.

Next, the effect of this embodiment will be described.
(1) Since the lid terminal member 14 and the electrode assembly 12 are integrated through the positive electrode tab group 30 and the negative electrode tab group 31, the lid 15 is pressed toward the case body 13. Thus, the electrode assembly 12 can be accommodated in the case body 13.

  At this time, the second joint portion 18b of the positive electrode conductive member 18 presses the tab side end surface 12a via the positive electrode tab group 30 of the electrode assembly 12, and the first joint portion 18a is adhered to the electrode assembly 12. Then, the first covering portion 12g of the tab side end surface 12a is pressed through the first tape 32. The dimension of the tab-side end surface 12a in the stacking direction of the first covering portion 12g is smaller than the dimension in the stacking direction of the electrode assembly 12 where the first tape 32 is not attached. For this reason, even if it is the tab side end surface 12a comprised by the 1st edge part 21a of the negative electrode 21, and the 1st edge part 26a of the separator 26, each 1st edge part 21a, 26a gathered together 1st coating | covering The portion 12g is more rigid than the portion where the first tape 32 is not attached, and is not easily crushed even when pressed by the first joint portion 18a. Therefore, the deformation of the electrode assembly 12 due to the pressing force when the electrode assembly 12 is housed in the case main body 13 can be suppressed.

  Similarly, the second joint portion 19b of the negative electrode conductive member 19 presses the tab side end surface 12a via the negative electrode tab group 31 of the electrode assembly 12, and the first joint portion 19a is adhered to the electrode assembly 12. Then, the second covering portion 12 h of the tab side end surface 12 a is pressed through the second tape 33. The dimension of the tab side end surface 12a in the stacking direction of the second covering portion 12h is smaller than the dimension of the electrode assembly 12 in the stacking direction of the portion where the second tape 33 is not attached. For this reason, even if it is the tab side end surface 12a comprised by the 1st edge part 21a of the negative electrode 21, and the 1st edge part 26a of the separator 26, each 2nd coating | covering by which each 1st edge parts 21a and 26a were gathered together. The portion 12h is more rigid than the portion where the second tape 33 is not attached, and is not easily crushed even when pressed by the first joint portion 19a. Therefore, the deformation of the electrode assembly 12 due to the pressing force when the electrode assembly 12 is housed in the case main body 13 can be suppressed.

  (2) Since the dimension in the stacking direction of the first covering portion 12g on the tab side end face 12a is smaller than the dimension in the stacking direction of the first joint portion 18a of the positive electrode conductive member 18, the negative electrode 21 and the separator 26 are first bonded. It is pressed by the part 18a. Similarly, since the dimension in the stacking direction of the second covering portion 12h of the tab side end face 12a is smaller than the dimension in the stacking direction of the first joint portion 19a of the negative electrode conductive member 19, the negative electrode 21 and the separator 26 are connected to the first joint. It is pressed by the part 18a. Therefore, it is possible to further suppress the deformation of the electrode assembly 12 due to the pressing force when the electrode assembly 12 is accommodated in the case main body 13.

  (3) The first tape 32 is attached to a position facing the positive electrode conductive member 18 in the height direction of the electrode assembly 12, and the second tape 33 is bonded to the negative electrode conductive member 19 in the height direction of the electrode assembly 12. It is stuck on the position facing. When the electrode assembly 12 is accommodated in the case body 13, the first joint portions 18 a and 19 a of the positive electrode conductive member 18 and the negative electrode conductive member 19 are in contact with the first tape 32 or the second tape 33. The first joining portions 18a and 19a press portions of the negative electrode 21 and the separator 26 that are reliably restrained by the first tape 32 or the second tape 33. Therefore, deformation of the electrode assembly due to the pressing force when the electrode assembly 12 is accommodated in the case main body 13 can be suppressed. Further, the first covering portion 12g can be protected by the first tape 32, the second covering portion 12h can be protected by the second tape 33, and the respective covering portions 12g and 12h are damaged by the pressing by the first joining portions 18a and 19a. Can be suppressed.

  (4) Since the positive electrode conductive member 18 and the negative electrode conductive member 19 press the tab side end surface 12a of the electrode assembly 12, it is not necessary to provide a separate portion for pressing the lid terminal member 14. Therefore, the configuration of the lid terminal member 14 can be simplified.

  (5) The first covering portion 12 g is on one end side in the width direction of the electrode assembly 12, and the second covering portion 12 h is on the other end side in the width direction of the electrode assembly 12. And when accommodating the electrode assembly 12 in the case main body 13, in order to press the width direction both ends of the tab side end surface 12a, compared with the case where the width direction one end side is pressed, the balance of the width direction of pressing force is Become good. Therefore, it is possible to further suppress the deformation of the electrode assembly 12 due to the pressing force when the electrode assembly 12 is accommodated in the case main body 13.

In addition, you may change the said embodiment as follows.
In the above embodiment, the positive electrode active material layer 23 of the positive electrode 20 is formed on both surfaces of the positive electrode metal foil 22, but may be formed only on one surface. The negative electrode active material layer 25 of the negative electrode 21 is formed on both sides of the negative electrode metal foil 24, but may be formed only on one side.

In the above embodiment, the negative electrode 21 and the separator 26 have the same size, but the separator 26 may be slightly larger than the negative electrode 21.
In the above embodiment, the negative electrode 21 and the separator 26 are slightly larger than the positive electrode 20, but the positive electrode 20 and the separator 26 may be slightly larger than the negative electrode 21. In this case, the first covering portion 12 g and the second covering portion 12 h are configured by the first edge portion 21 a of the positive electrode 20 and the first edge portion 26 a of the separator 26.

  In the above embodiment, the dimensions in the stacking direction of the first covering portion 12g to which the first tape 32 is attached and the second covering portion 12h to which the second tape 33 is attached are the positive electrode conductive member 18 and the negative electrode conductive member. Although the dimension in the stacking direction of the first joint portions 18a and 19a of the member 19 is shorter than the dimension in the stacking direction of the covering portions 12g and 12h, the dimension in the stacking direction of the first joint portions 18a and 19a is the same or longer. May be. However, the covering portions 12g and 12h are converged into a tapered shape so as to be shorter than the dimension in the stacking direction of the electrode assembly 12 where the first tape 32 and the second tape 33 are not attached.

  In the above embodiment, the longitudinal ends of the first tape 32 and the second tape 33 are attached to the upper side in the height direction of the first end surface 12c or the second end surface 12d of the electrode assembly 12, The 1st tape 32 and the 2nd tape 33 may be stuck to the height direction lower side of the 1st end face 12c or the 2nd end face 12d, or may be stuck to the bottom end face 12b.

  In the above embodiment, the first tape 32 and the second tape 33 are attached to both ends in the width direction of the electrode assembly 12 to provide the covering portions 12g and 12h. You may stick to only one side. Further, not only at both ends of the electrode assembly 12 in the width direction, a covering portion may be provided by sticking a tape at the center in the width direction.

  In the above embodiment, the electrode assembly 12 is constrained in the stacking direction by the first tape 32 and the second tape 33, whereby the first cover portion 12g and the second cover portion 12h of the tab side end surface 12a are dimensioned in the stack direction. However, it may be constrained by other than tape.

  For example, as shown in FIG. 6, the electrode assembly 12 is covered with an insulating film 36 as a covering member for insulating the case body 13. The insulating film 36 is made of a sheet-like insulating material. In this case, when covering the electrode assembly 12 with the insulating film 36, the end portions of the insulating film 36 are welded while restraining both ends in the width direction and upper portions in the height direction of the electrode assembly 12 in the stacking direction. Therefore, similarly to the restraint by the first tape 32 and the second tape 33, the dimension in the stacking direction of the first covering portion 12g and the second covering portion 12h of the tab side end surface 12a can be reduced.

  In the above embodiment, the first joint portions 18a and 19a of the positive electrode conductive member 18 and the negative electrode conductive member 19 press the covering portions 12g and 12h covered with the first tape 32 or the second tape 33. In order to press the tab side end surface 12a to the lid terminal member 14, you may provide a press part separately.

  In the above embodiment, the first tape 32 and the second tape 33 are attached to the portions pressed by the first joint portions 18a and 19a of the positive electrode conductive member 18 and the negative electrode conductive member 19, but the first tape 32 and the second tape 33 The two tapes 33 may be attached to portions that are not pressed by the first joint portions 18a and 19a. In this case, the first joint portions 18a and 19a are in contact with the tab-side end surface 12a having a dimension smaller than the dimension in the stacking direction of at least a portion of the electrode assembly 12 where the first tape 32 and the second tape 33 are not attached. Just touch.

  In the said embodiment, although the 3rd tape 34 and the 4th tape 35 were stuck so that the bottom side end surface 12b of the electrode assembly 12 might be covered, you may abbreviate | omit. However, it is preferable that the positive electrode 20, the negative electrode 21, and the separator 26 are attached from the viewpoint of suppressing the stacking deviation. Moreover, you may affix a tape so that the other end surface (1st-4th end surface 12c-12f) of the electrode assembly 12 may be covered, and suppress a lamination | stacking shift | offset | difference.

  In the above embodiment, the positive electrode terminal 16 and the positive electrode conductive member 18 have different configurations, but may be an integrated positive electrode terminal. Similarly, although the negative electrode terminal 17 and the negative electrode conductive member 19 have different configurations, they may be integrated negative electrodes.

The power storage device can also be applied to power storage devices other than secondary batteries, such as capacitors.
The secondary battery 10 may be a lithium ion secondary battery or another secondary battery. In short, any ion may be used as long as ions move between the active material for the positive electrode and the active material for the negative electrode and charge is transferred.

Next, a technical idea that can be grasped from the above embodiment and another example will be added below.
(A) The power storage device is a secondary battery.

  DESCRIPTION OF SYMBOLS 12 ... Electrode assembly, 12a ... Tab side end face as end face, 12g ... 1st coating | coated part as a coating | coated part, 12h ... 2nd coating | coated part as a coating | coated part, 13 ... Case main body, 14 ... Cover terminal member, 15 ... Lid, 16 ... positive electrode terminal as electrode terminal, 17 ... negative electrode terminal as electrode terminal, 18 ... positive electrode conductive member as conductive member, 18a ... first junction as pressing part, 19 ... negative electrode conductive member as conductive member , 19a: a first joining portion as a pressing portion, 20: a positive electrode, 21 ... a negative electrode, 26 ... a separator, 28 ... a positive current collecting tab as an uncoated portion, 29 ... a negative current collecting as an uncoated portion Tab: 30 ... Positive electrode tab group as an uncoated portion group, 31 ... Negative electrode tab group as an uncoated portion group, 32 ... First tape as a covering member, 33 ... Second tape as a covering member, 36 ... Insulating film as a covering member.

Claims (5)

An electrode set having an uncoated portion group in which a positive electrode and a negative electrode are stacked in a state where they are insulated from each other by a separator, and an uncoated portion having a shape protruding from one side of the positive electrode and the negative electrode is stacked Solid,
A bottomed box-shaped case body having an opening for accommodating the electrode assembly;
A lid for closing the opening of the case main body, an electrode terminal fixed to the lid, for transmitting and receiving electricity to and from the electrode assembly, and an electrically connected electrically connecting the uncoated part group and the electrode terminal A lid terminal member integrated with the member,
The electrode assembly includes an end surface having the uncoated portion group, and has a covering portion covered by a covering member on the end surface,
The dimension of the covering portion in the stacking direction of the positive electrode, the negative electrode, and the separator is smaller than the dimension in the stacking direction of the portion of the electrode assembly that is not covered by the covering member. Power storage device.   The power storage device according to claim 1, wherein the lid terminal member has a pressing portion that presses the end face when the electrode assembly is accommodated in the case body.   The power storage device according to claim 2, wherein a dimension of the covering portion in the stacking direction is smaller than a dimension of the pressing portion in the stacking direction.   The power storage device according to claim 2, wherein the pressing portion is located at a position facing the covering member.   The power storage device according to claim 2, wherein the pressing portion is the conductive member.

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