JP5699986B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device having an electrode assembly in which first electrodes and second electrodes having different polarities are alternately stacked with a separator interposed therebetween to form a layer.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. This type of secondary battery is disclosed in Patent Document 1, for example. The secondary battery is an electrode assembly in which a negative electrode with a negative electrode active material applied to a metal foil and a positive electrode with a positive electrode active material applied to a metal foil are insulated with a separator made of a microporous film and laminated in layers. Have Patent Document 1 discloses a technique in which a negative electrode or a positive electrode is sandwiched between two separators and the periphery of the two separators is bonded with an adhesive or an adhesive tape.

JP 2008-130360 A

  Since Patent Document 1 has a configuration in which an electrode is sandwiched between two separators and the periphery of the separator is adhered, an adhesive or an adhesive tape is previously adhered to a peripheral portion of one separator before the electrode is sandwiched between the separators. There is a need. That is, in the case of an adhesive tape, a double-sided tape having an adhesive surface on both sides is used. And in patent document 1, since another separator is piled up with the separator which adhere | attached the adhesive agent or the adhesive tape previously, it is hard to say that the workability | operativity for pinching an electrode with a separator is good. Therefore, the productivity of the secondary battery may be reduced.

  The present invention has been made paying attention to such problems existing in the prior art, and an object thereof is to provide a power storage device capable of improving productivity.

  In order to solve the above-described problem, the invention according to claim 1 includes a first electrode, a second electrode having a polarity different from that of the first electrode, the first electrode, and the second electrode. An electrode assembly that is alternately laminated with separators interposed therebetween to form a layer, and the separator includes a first sheet portion that covers one surface of the first electrode and a second sheet portion that covers the other surface The gist of the invention is that it has an adhesive portion where the outer surface of the first sheet portion and the inner surface of the second sheet portion are bonded with an adhesive tape.

  According to this, the 1st electrode will be in the state pinched | interposed by adhere | attaching the outer surface of the 1st sheet | seat part in a separator, and the inner surface of a 2nd sheet | seat part with an adhesive tape. That is, when combining the first electrode and the separator, the adhesive tape may be applied across the outer surface of the first sheet portion and the inner surface of the second sheet portion, and the workability is good. And when manufacturing an electrode assembly, it can handle in the state which put together the 1st electrode and the separator. For this reason, the lamination process which laminates | stacks a 1st electrode, a 2nd electrode, and a separator can be simplified. Therefore, productivity of the power storage device can be improved.

  According to a second aspect of the present invention, in the power storage device according to the first aspect, the first electrode is provided with a current collecting tab so as to protrude from one end, and the adhesive portion includes the current collecting portion. The gist is that the tab is located on one end side where the tab protrudes. According to this, an adhesion part can be accommodated in the space which accommodates a current collection tab, and it becomes space saving.

  A third aspect of the present invention is the power storage device according to the second aspect, wherein the current collecting tab is bonded with the adhesive tape together with the first sheet portion and the second sheet portion. According to this, since the current collecting tab is bonded together with the first sheet portion and the second sheet portion, the current collecting tab can be fixed to the separator. Therefore, it becomes easy to handle when manufacturing the electrode assembly, and the productivity of the power storage device can be improved.

  According to a fourth aspect of the present invention, in the power storage device according to any one of the first to third aspects, the separator is configured such that the first sheet portion and the second sheet portion are connected by a folded portion. It is a summary. According to this, since the first electrode is sandwiched by folding the separator, the first electrode and the separator can be combined without increasing the number of adhesion portions, and workability is good.

  According to a fifth aspect of the present invention, in the power storage device according to the fourth aspect, the length of the first sheet portion from the side forming the folded portion to the opposite side is shorter than the second sheet portion. The gist is that the adhesive portion is located along the opposite side of the first sheet portion. According to this, the edge of the 1st sheet part and the 2nd sheet part has shifted, and it can stick an adhesive tape easily across the 1st sheet part and the 2nd sheet part. Therefore, workability when attaching the adhesive tape is good.

  The invention according to claim 6 is the power storage device according to any one of claims 1 to 5, wherein the first electrode is a positive electrode active material obtained by applying a positive electrode active material to a metal foil for positive electrode. A positive electrode having a layer, the second electrode is a negative electrode having a negative electrode active material layer obtained by applying a negative electrode active material to a metal foil for negative electrode, and the application region of the positive electrode active material in the positive electrode is The gist is that it is smaller than the coating area of the negative electrode active material in the negative electrode.

  According to this, since the positive electrode having a small active material application region is sandwiched between the separators, it is possible to suppress an increase in the size (size) of the electrode assembly as compared with the case where the negative electrode is sandwiched between the separators. .

  The invention according to claim 7 is the power storage device according to any one of claims 1 to 6, wherein the separator is coated with ceramic. According to this, even if it is the separator coated with the ceramic, it can be easily put together with an electrode, and workability | operativity is good.

  The gist of an eighth aspect of the present invention is the power storage device according to any one of the first to seventh aspects, wherein the power storage device is a secondary battery. According to this, the productivity of the secondary battery can be improved.

  According to the present invention, productivity can be improved.

The perspective view which shows the external appearance of a secondary battery. (A) is a front view of a positive electrode sheet, (b) is the 1-1 sectional view taken on the line of (a). (A) is a front view of a negative electrode sheet, (b) is 2-2 sectional view taken on the line of (a). The schematic diagram which shows the state which laminated | stacked the positive electrode sheet, the negative electrode sheet, and the separator. (A) is a front view which shows the positive electrode accommodating sheet of 1st Embodiment, (b) is the 3-3 sectional view taken on the line of (a). The perspective view which shows a mode that a positive electrode sheet is piled up on the separator of 1st Embodiment. (A) is a perspective view which shows a mode that a separator is folded, (b) is a front view which shows the separator after folding. The front view which shows the positive electrode storage sheet of 2nd Embodiment. The perspective view which shows a mode that a positive electrode sheet is piled up on the separator of 2nd Embodiment. (A) is a front view which shows the positive electrode accommodating sheet of 3rd Embodiment, (b) is the 4-4 sectional view taken on the line of (a). The perspective view which shows a mode that a positive electrode sheet is piled up on the separator of 3rd Embodiment.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, in a secondary battery 10 as a power storage device, an electrode assembly 12 is accommodated in a battery case 11. The battery case 11 includes a rectangular parallelepiped main body member 13 and a rectangular flat plate-shaped lid member 14. The lid member 14 closes the insertion port for inserting the electrode assembly 12 into the main body member 13. Both the main body member 13 and the lid member 14 constituting the battery case can 11 are made of metal (for example, stainless steel or aluminum). Further, the secondary battery 10 of the present embodiment is a prismatic battery whose appearance is square. Further, the secondary battery 10 of the present embodiment is a lithium ion battery.

  A positive electrode terminal 15 and a negative electrode terminal 16 for taking out electricity from the electrode assembly 12 are electrically connected to the electrode assembly 12. The positive electrode terminal 15 and the negative electrode terminal 16 are respectively attached with ring-shaped insulating rings 17 a for insulating from the battery case can 11.

  The electrode assembly 12 includes a positive electrode sheet 18 as a first electrode, a negative electrode sheet 19 as a second electrode, and a separator 20 that insulates between the positive electrode sheet 18 and the negative electrode sheet 19. The electrode assembly 12 is configured by alternately laminating separators 20 between a plurality of positive electrode sheets 18 and a plurality of negative electrode sheets 19. That is, the electrode assembly 12 is provided with a plurality of sets each including the positive electrode sheet 18, the negative electrode sheet 19, and the separator 20. The separator 20 of the present embodiment is a ceramic separator obtained by coating a microporous film with ceramic.

  2A and 2B, the positive electrode sheet 18 includes a positive electrode metal foil (aluminum foil in this embodiment) 21 and a positive electrode active material layer 22 formed by applying a positive electrode active material on both surfaces thereof. Have Further, the positive electrode metal foil 21 to which the positive electrode active material is not applied constitutes the non-coated portion 23. A positive electrode current collecting tab 24 made of the positive electrode metal foil 21 is provided on the edge portion 18 a as one end of the positive electrode sheet 18 so as to protrude. The positive electrode current collecting tab 24 is a part of the non-coated portion 23. The positive current collecting tab 24 is electrically connected to the positive terminal 15. The positive electrode current collecting tab 24 is formed in the same position and in the same shape in each positive electrode sheet 18 constituting the electrode assembly 12.

  As shown in FIGS. 3A and 3B, the negative electrode sheet 19 includes a negative electrode metal foil (copper foil in the present embodiment) 25 and a negative electrode active material layer 26 formed by applying a negative electrode active material on both surfaces thereof. Have Further, the negative electrode metal foil 25 to which the negative electrode active material is not applied constitutes the non-coated portion 27. The negative electrode current collecting tab 28 made of the negative electrode metal foil 25 is provided on the edge 19 a as one end of the negative electrode sheet 19 so as to protrude. The negative electrode current collecting tab 28 is a part of the non-coated portion 27. The negative electrode current collecting tab 28 is electrically connected to the negative electrode terminal 16. The negative electrode current collecting tab 28 is formed in the same position and in the same shape in each negative electrode sheet 19 constituting the electrode assembly 12. The negative electrode current collecting tab 28 is provided at a position where it does not overlap the positive electrode current collecting tab 24 when the positive electrode sheet 18 and the negative electrode sheet 19 are laminated.

  In the present embodiment, as shown in FIG. 4, the positive electrode sheet 18 has both the lengths in the height direction X and the width direction Y smaller than the lengths in the height direction X and the width direction Y of the negative electrode sheet 19. The height direction X is a direction along the protruding direction of the positive electrode current collecting tab 24 of the positive electrode sheet 18 and the negative electrode current collecting tab 28 of the negative electrode sheet 19. On the other hand, the width direction Y is a direction orthogonal to the height direction X, that is, a direction orthogonal to the protruding direction of the positive electrode current collecting tab 24 and the negative electrode current collecting tab 28. The height direction X and the width direction Y are directions orthogonal to the stacking direction of the positive electrode sheet 18 and the negative electrode sheet 19.

  The length in the height direction X is the length of the region excluding the positive electrode current collecting tab 24 in the positive electrode sheet 18. Further, the length in the height direction X is the length of the region excluding the negative electrode current collecting tab 28 in the negative electrode sheet 19. The separator 20 has the same length in the height direction X and the width direction Y as the length in the height direction X and the width direction Y of the negative electrode sheet 19. In FIG. 4, for convenience of description, in order to illustrate the separator 20, a line (two-dot chain line) indicating the outline of the separator 20 is shown inside the line (solid line) indicating the outline of the negative electrode sheet 19. However, they actually overlap.

  In the positive electrode sheet 18, a positive electrode active material layer 22 is formed in a region determined by the height direction X and the width direction Y. Similarly, a negative electrode active material layer 26 is formed in the negative electrode sheet 19 in a region defined by the height direction X and the width direction Y. When the region of the positive electrode active material layer 22 of the positive electrode sheet 18 and the region of the negative electrode active material layer 26 of the negative electrode sheet 19 are compared, the application region of the positive electrode active material in the positive electrode sheet 18 is the negative electrode active material in the negative electrode sheet 19. Small compared to the application area. In the electrode assembly 12, a region where the positive electrode active material layer 22 of the positive electrode sheet 18 and the negative electrode active material layer 26 of the negative electrode sheet 19 overlap in the stacking direction is the facing portion 29 of the active material layer. The facing part 29 is a part that contributes to the chemical reaction of the battery.

  The electrode assembly 12 of the present embodiment is configured by alternately stacking positive electrode storage sheets 30 (shown in FIG. 5) in which the positive electrode sheets 18 are sandwiched and stored between separators 20 and negative electrode sheets 19. When manufacturing the electrode assembly 12, the positive electrode sheet 18 and the separator 20 are unitized as the positive electrode storage sheet 30, whereby the stacking process of the positive electrode sheet 18, the negative electrode sheet 19 and the separator 20 can be simplified. The production efficiency can be improved. In addition, when the positive electrode sheet 18, the negative electrode sheet 19, and the separator 20 are each made into one independent sheet | seat, the four processes of laminating | stacking the positive electrode sheet 18, the separator 20, the negative electrode sheet 19, and the separator 20 in order are required. In addition, it is necessary to perform alignment when the separator 20 is laminated on the positive electrode sheet 18 and when the negative electrode sheet 19 is laminated on the separator 20. On the other hand, when the positive electrode storage sheet 30 is used, if the negative electrode sheet 19 is stacked on the positive electrode storage sheet 30, the separator 20 can be interposed between the positive electrode sheet 18 and the negative electrode sheet 19. Thus, the number of processes is reduced as compared with the case of laminating independent sheets. Further, alignment may be performed when the negative electrode sheet 19 is laminated on the positive electrode storage sheet 30. Since the electrode assembly 12 is formed by laminating a large number of positive electrode sheets 18 and negative electrode sheets 19 such as 50 sheets or 60 sheets, reducing the number of steps of the lamination process improves the productivity of the electrode assembly 12. Can contribute greatly.

Hereinafter, the positive electrode storage sheet 30 according to the present embodiment will be described in detail with reference to FIGS.
As shown in FIGS. 5A and 5B, the separator 20 includes a first sheet surface 32 as a first sheet portion covering one surface of the positive electrode sheet 18 and a second sheet portion covering the other surface of the positive electrode sheet 18. The first sheet surface 32 and the second sheet surface 33 are connected to each other at the folded portion 31. The inner surface 32 b of the first sheet surface 32 and the inner surface 33 b of the second sheet surface 33 face the positive electrode sheet 18. The outer surface 32 c of the first sheet surface 32 and the outer surface 33 c of the second sheet surface 33 do not face the positive electrode sheet 18.

  As shown in FIGS. 5A and 6, the length H1 from the side 31 a forming the folded portion 31 to the opposite side 32 a on the first sheet surface 32 is from the side 31 a to the opposite side 33 a on the second sheet surface 33. It is shorter than the length H2. Thereby, when the 1st sheet surface 32 and the 2nd sheet surface 33 are piled up, the edge (opposite side 32a, opposite side 33a) of the 1st sheet surface 32 and the 2nd sheet surface 33 will shift. These lengths H <b> 1 and H <b> 2 are lengths in the height direction X of the positive electrode sheet 18, that is, the direction along the protruding direction of the positive electrode current collecting tab 24 in a state where the positive electrode sheet 18 is accommodated in the separator 20. The length H3 of the side 31a is the length in the direction along the width direction Y of the positive electrode sheet 18. This length H3 is the same length between the opposite side 32a and the opposite side 33a.

  As shown in FIG. 5A, the adhesive tape 34 is attached along the opposite side 32 a of the first sheet surface 32 across the opposite side 32 a. Adhesive region as an adhesive part along which the part of the outer surface 32c of the first sheet surface 32 (the back surface of the inner surface 32b) and the part of the inner surface 33b of the second sheet surface 33 are bonded to the adhesive tape 34 along the opposite side 32a. 37. The adhesive region 37 is located on the edge 18 a side where the positive electrode current collecting tab 24 is formed to protrude from the positive electrode sheet 18, and the positive electrode current collecting tab 24 protruding from the opposite side 32 a is first bonded by the adhesive tape 34. The sheet surface 32 and the second sheet surface 33 are bonded together. Thereby, the positive electrode sheet 18 is fixed to the separator 20, and the displacement of the positive electrode sheet 18 is suppressed.

  The length H1 is set so that the adhesion region 37 does not overlap the positive electrode active material layer 22 of the positive electrode sheet 18, and the length H2 is set so that the adhesion region 37 fits on the inner surface 33b of the second sheet surface 33. Has been.

  The positive electrode storage sheet 30 is produced according to the procedure shown in FIGS. First, as shown in FIG. 6, the positive electrode sheet 18 is overlaid on the separator 20 that is in a square sheet state in plan view. Next, as shown in FIG. 7A, the separator 20 is folded at the folding portion 31 so that the positive electrode sheet 18 is sandwiched between the separators 20. As a result, the positive electrode sheet 18 is sandwiched between the separators 20 as shown in FIG.

  Thereafter, as shown in FIG. 5 (a), the first sheet surface 32 and the second sheet surface 33 facing each other with the positive electrode sheet 18 interposed therebetween are bonded together with the adhesive tape 34 along the opposite side 32a. 30 is completed.

Hereinafter, the operation of the present embodiment will be described.
The electrode assembly 12 is configured by alternately stacking positive electrode storage sheets 30 and negative electrode sheets 19 that store positive electrode sheets 18. The positive electrode storage sheet 30 is produced by folding the single separator 20 to sandwich the positive electrode sheet 18 and bonding the first sheet surface 32 and the second sheet surface 33 with an adhesive tape 34. In this embodiment, since the positive electrode sheet 18 is sandwiched between the first sheet surface 32 and the second sheet surface 33 that are deformed when the separator 20 is folded back, the first sheet surface 32 and the second sheet surface 33 can be easily bonded. It becomes. Specifically, the first sheet surface 32 and the second sheet surface 33 are adhered so as to straddle the inner surface 33b of the second sheet surface 33 and the outer surface 32c of the first sheet surface 32 adjacent to the inner surface 33b. What is necessary is just to affix the tape 34. FIG. For this reason, preparation of the positive electrode storage sheet 30 is easy.

  Then, by manufacturing the electrode assembly 12 using the positive electrode storage sheet 30 thus manufactured, the stacking process of the positive electrode sheet 18, the negative electrode sheet 19 and the separator 20 is simplified, and the manufacturing efficiency of the electrode assembly 12 is increased. It can improve. As a result, the productivity of the secondary battery 10 can be improved.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) The positive electrode sheet 18 is sandwiched between the outer surface 32 c of the first sheet surface 32 and the inner surface 33 b of the second sheet surface 33 of the separator 20 by the adhesive tape 34. That is, when the positive electrode sheet 18 and the separator 20 are combined into the positive electrode storage sheet 30, the adhesive tape 34 is applied so as to straddle the outer surface 32 c of the first sheet surface 32 and the inner surface 33 b of the second sheet surface 33. It can be attached and workability is good. When manufacturing the electrode assembly 12, the positive electrode sheet 18 and the separator 20 can be handled together. For this reason, the lamination process which laminates | stacks the positive electrode sheet 18, the negative electrode sheet 19, and the separator 20 can be simplified. Therefore, the productivity of the secondary battery 10 can be improved.

  (2) The adhesion region 37 is formed on the edge portion 18a side of the positive electrode sheet 18 on which the positive electrode current collecting tab 24 is protruded. For this reason, the adhesion area | region 37 (adhesive tape 34) can be accommodated in the space which accommodates the positive electrode current collection tab 24, and becomes space-saving.

  (3) The positive electrode current collecting tab 24 is bonded together with the first sheet surface 32 and the second sheet surface 33. Thereby, the positive electrode current collection tab 24 can be fixed to the separator 20. Therefore, it becomes easy to handle when manufacturing the electrode assembly 12, and the productivity of the secondary battery 10 can be improved.

  (4) By forming the adhesion region 37 on the edge 18a side of the positive electrode sheet 18 and covering the positive electrode current collecting tab 24 with the adhesive tape 34, a short circuit between the positive electrode current collecting tab 24 and the negative electrode sheet 19 can be prevented. .

  (5) The positive electrode sheet 18 is sandwiched by folding back one separator 20. For this reason, the positive electrode sheet 18 and the separator 20 can be combined without increasing the number of the adhesion regions 37. For example, when the positive electrode sheet 18 is sandwiched between the pair of separators 20, it is better to increase the adhesion region 37 in order to firmly fix the positive electrode sheet 18 and the separator 20, but workability is reduced.

  (6) When the first sheet surface 32 and the second sheet surface 33 are overlapped, the end of the first sheet surface 32 and the second sheet surface 33 (opposite side 32a, opposite side 33a) is displaced, so that the adhesive region 37 is formed. It is formed. For this reason, the adhesive tape 34 can be easily applied across the first sheet surface 32 and the second sheet surface 33. Therefore, workability when the adhesive tape 34 is applied is good.

  (7) Since the positive electrode sheet 18 having a small active material application region is sandwiched between the separators 20, the size (size) of the electrode assembly 12 is prevented from being increased as compared with the case where the negative electrode sheet 19 is sandwiched between the separators 20. be able to.

  (8) Even when a ceramic separator is used, the positive electrode sheet 18 can be sandwiched between the separators. Ceramic separators are difficult to join by welding. However, if the positive electrode storage sheet 30 is produced using the adhesive tape 34 as in this embodiment, the positive electrode sheet 18 can be easily sandwiched even with a ceramic separator.

(Second Embodiment)
Next, a second embodiment embodying the present invention will be described with reference to FIGS.
In the embodiments described below, the same components as those already described are denoted by the same reference numerals, and redundant description thereof is omitted or simplified.

  As shown in FIGS. 8 and 9, the separator 40 of the present embodiment, which is a ceramic separator coated with ceramic, has a first sheet surface 32 and a second sheet surface 33 connected to each other at the folded portion 31. Yes.

  In the first sheet surface 32, a length H4 from the side 31a that is the folded portion 31 to one end 40a that is the opposite side, and a length from the side 31a to the other end 40b that is the opposite side in the second sheet surface 33 H5 is the same length. A plurality of (four in this embodiment) tongue pieces 41 are formed to protrude from the end portion 40a. In addition, a plurality (four in this embodiment) of tongue pieces 42 are formed to protrude from the end portion 40b.

  Each of the tongue piece 41 and the tongue piece 42 is formed in a rectangular shape in plan view at a predetermined interval along the end portions 40a and 40b, and is formed in the same size. That is, the protruding lengths of the tongue piece 41 and the tongue piece 42 are formed to be the same length. In the direction along the end portions 40 a and 40 b, the width of each tongue piece 41 and 42 is smaller than the width of the positive electrode current collecting tab 24. Further, both the tongue piece 41 and the tongue piece 42 are formed by cutting the separator 40. And the tongue piece 41 and the tongue piece 42 are formed in each edge part 40a, 40b so that it may arrange | position alternately (alternately) in the state which turned the separator 40 in the folding | returning part 31. FIG. That is, in a state where the separator 40 is folded, the tongue pieces 41 and the tongue pieces 42 are adjacent to each other without overlapping.

  The adhesive tape 34 is affixed across the tongue pieces 41 and 42 arrange | positioned alternately along the edge part 40a. An adhesive region 37 as an adhesive portion where the tongue piece 41 which is a part of the outer surface 32c of the first sheet surface 32 and the tongue piece 42 which is a part of the inner surface 33b of the second sheet surface 33 are bonded to the adhesive tape 34; Become. The adhesive region 37 is located on the edge 18a side where the positive electrode current collecting tab 24 protrudes from the positive electrode sheet 18, and the positive electrode current collecting tab 24 is attached to the first sheet surface 32 and the second sheet by the adhesive tape 34. Bonded together with the sheet surface 33. Thereby, the positive electrode sheet 18 is fixed to the separator 40, and the displacement of the positive electrode sheet 18 is suppressed.

  And in this embodiment, the positive electrode accommodation sheet | seat 43 which pinched | interposed and accommodated the positive electrode sheet 18 shown in FIG. 8 is produced in the following procedure. First, as shown in FIG. 9, the positive electrode sheet 18 is superimposed on a sheet-like separator 40 having a substantially square shape in plan view. Next, the separator 40 is folded back so that the positive electrode sheet 18 is sandwiched between the separators 40. As a result, the positive electrode sheet 18 is sandwiched between the separators 40 as shown in FIG. Thereafter, the first sheet surface 32 and the second sheet surface 33 that are opposed to each other with the positive electrode sheet 18 interposed therebetween are bonded with the adhesive tape 34, whereby the positive electrode storage sheet 43 is completed.

Hereinafter, the operation of the present embodiment will be described with a focus on differences from the operation of the first embodiment.
In the present embodiment, since the positive electrode sheet 18 is sandwiched between the first sheet surface 32 and the second sheet surface 33 that are deformed when the separator 40 is folded back, the first sheet surface 32 and the second sheet surface 33 can be easily bonded. . That is, as shown in FIG. 8, when the separator 40 is folded back, the tongue pieces 41 and the tongue pieces 42 are alternately arranged. For this reason, the first sheet surface 32 and the second sheet surface 33 are adhered so as to straddle the outer surface 32c of the first sheet surface 32 of the tongue piece 41 and the inner surface 33b of the second sheet surface 33 of the tongue piece 42. What is necessary is just to affix the tape 34. FIG. For this reason, it is easy to produce the positive electrode storage sheet 43. Therefore, according to the present embodiment, the same effects as the effects (1) to (8) of the first embodiment can be obtained.

(Third embodiment)
Next, a third embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIGS. 10A and 10B, the separator 50 according to the present embodiment, which is a ceramic separator coated with ceramic, includes a first sheet surface 32 and a second sheet surface 33 that are connected at the folded portion 31. have. In the first sheet surface 32, the length H6 from the side 31a that is the folded portion 31 to one end 50a that is the opposite side, and the length from the side 31a to the other end 50b that is the opposite side in the second sheet surface 33 H7 has the same length, and the end 50a and the end 50b overlap in a state where the separator 50 is folded. In the vicinity of the end portion 50a of the first sheet surface 32, a plurality of (three in this embodiment) hole portions 51 penetrating the separator 50 are formed at predetermined intervals along the end portion 50a. On the other hand, the hole 51 is not formed in the second sheet surface 33.

  In addition, each hole 51 is formed at a position that does not overlap the area of the positive electrode sheet 18 excluding the positive electrode current collecting tab 24 in a state where the separator 50 sandwiches the positive electrode sheet 18. That is, each hole 51 is formed at a position that overlaps with the positive electrode current collecting tab 24, the inner surface 33 b of the second sheet surface 33, and the positive electrode current collecting tab 24 when the separator 50 is folded back. The adhesive tape 34 is affixed so as to cover the hole 51 along the end 50a. A part of the outer surface 32 c of the first sheet surface 32 and a part of the inner surface 33 b of the second sheet surface 33 serve as an adhesion region 37 as an adhesion part to be adhered to the adhesive tape 34. The adhesive region 37 is located on the edge 18a side where the positive electrode current collecting tab 24 protrudes from the positive electrode sheet 18, and the positive electrode current collecting tab 24 is attached to the first sheet surface 32 and the second sheet by the adhesive tape 34. Bonded together with the sheet surface 33. Thereby, the positive electrode sheet 18 is fixed to the separator 50, and the displacement of the positive electrode sheet 18 is suppressed.

  And in this embodiment, the positive electrode accommodation sheet | seat 52 which pinched | interposed and accommodated the positive electrode sheet 18 shown to Fig.10 (a) is produced in the following procedure. First, as shown in FIG. 11, the positive electrode sheet 18 is superimposed on a sheet-like separator 50 having a substantially rectangular shape in plan view. Next, the separator 50 is folded back so that the positive electrode sheet 18 is sandwiched between the separators 50. As a result, the positive electrode sheet 18 is sandwiched between the separators 50 as shown in FIG. Thereafter, the first sheet surface 32 and the second sheet surface 33 that are opposed to each other with the positive electrode sheet 18 interposed therebetween are bonded with the adhesive tape 34, thereby completing the positive electrode storage sheet 52.

Hereinafter, the operation of the present embodiment will be described with a focus on differences from the operation of the first embodiment.
In the present embodiment, since the positive electrode sheet 18 is sandwiched between the first sheet surface 32 and the second sheet surface 33 that are deformed when the separator 50 is folded back, the first sheet surface 32 and the second sheet surface 33 can be easily bonded. . That is, as shown in FIG. 10A, when the separator 50 is folded back, the hole 51 overlaps the inner surface 33 b of the second sheet surface 33. Therefore, the adhesive tape 34 is bonded to the first sheet surface 32 and the second sheet surface 33 so as to straddle the outer surface 32 c of the first sheet surface 32 and the inner surface 33 b of the second sheet surface 33 overlapping the hole 51. Can be pasted. For this reason, the production of the positive electrode storage sheet 52 is easy. Therefore, according to the present embodiment, the same effects as the effects (1) to (8) of the first embodiment can be obtained.

Each embodiment may be changed as follows.
In each embodiment, the separators 20, 40, 50 may be separators that are not coated with ceramic.

  In each embodiment, the separators 20, 40, 50 may be constituted by a pair of separators. That is, instead of folding back one separator as in each embodiment, after the two separators are superimposed on the positive electrode sheet 18, the adhesive tape 34 is attached to the adhesive region 37 to bond the two separators together. May be. The gist of this another example is that the first sheet surface 32 and the second sheet surface 33 described in each embodiment are formed by separate separators and bonded together.

In each embodiment, the positive electrode current collecting tab 24 may not be bonded together with the first sheet surface 32 and the second sheet surface 33.
In each embodiment, the negative electrode sheet 19 may be formed by sandwiching the negative electrode sheet 19 between the separators 20, 40, and 50 described in each embodiment. The electrode assembly 12 is configured by laminating a positive electrode sheet 18 and a negative electrode storage sheet.

In each embodiment, the positive electrode active material layer 22 may be formed on one side of the positive electrode metal foil 21. Similarly, the negative electrode active material layer 26 may be formed on one surface of the negative electrode metal foil 25.
(Circle) the secondary battery 10 of each embodiment may be mounted in a motor vehicle as a vehicle, and may be mounted in an industrial vehicle. Further, the present invention may be applied to a stationary power storage device.

The configuration of each embodiment may be applied to other power storage devices such as electric double layer capacitors.
The secondary battery 10 of each embodiment is a lithium ion secondary battery, but is not limited thereto, and may be another secondary battery. 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.

In each embodiment, the shapes of the positive electrode sheet 18, the negative electrode sheet 19, and the separators 20, 40, 50 may be changed. For example, it may be formed in a square in front view.
In each embodiment, the separators 20, 40, 50 may be larger than the negative electrode sheet 19.

  ○ In the second embodiment, a gap is formed between the tongue piece 41 and the tongue piece 42 when the separator 40 is folded, but the tongue piece 41 and the tongue piece 42 are formed so that the gap is not formed. Also good. In this case, the positive electrode current collector tab 24 or the tongue piece 41 and the tongue piece 42 are disposed so that the entire positive electrode current collector tab 24 does not overlap the tongue piece 41 in the direction along the end 40b. The tab 24 can be bonded together with the first sheet surface 32 and the second sheet surface 33 by the adhesive tape 34.

  In the second embodiment, the shape of the tongue pieces 41 and 42 may be changed. That is, the shape of the tongue piece 41 and the tongue piece 42 is not limited as long as a region where the tongue piece 41 and the tongue piece 42 do not overlap when the separator 40 is folded back is formed.

In the third embodiment, a recess formed by cutting out the end of the separator 50 instead of the hole 51 may be used.
In the third embodiment, the hole 51 may be formed at a position that does not overlap with the positive electrode current collecting tab 24.

Next, a technical idea that can be grasped from the above embodiment and another example will be added below.
(A) While the outer surface of a sheet | seat part is a surface which contact | connects a 2nd electrode, the inner surface of a sheet | seat part is a surface which contact | connects a 1st electrode. The power storage device described.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery, 12 ... Electrode assembly, 18 ... Positive electrode sheet, 18a ... Edge, 19 ... Negative electrode sheet, 20, 40, 50 ... Separator, 21 ... Metal foil for positive electrodes, 22 ... Positive electrode active material layer, 24 DESCRIPTION OF SYMBOLS ... Positive electrode current collection tab, 25 ... Metal foil for negative electrodes, 26 ... Negative electrode active material layer, 31 ... Folding part, 31a ... Side, 32 ... 1st sheet surface, 33 ... 2nd sheet surface, 32a, 33a ... Opposite side, 32b 33b ... inner surface, 32c, 33c ... outer surface, 34 ... adhesive tape, 37 ... adhesion region, H1, H2 ... length.

Claims (8)

A first electrode;
A second electrode having a different polarity from the first electrode;
An electrode assembly in which the first electrode and the second electrode are alternately stacked with a separator interposed therebetween to form a layer, and
The separator has a first sheet portion covering one surface of the first electrode and a second sheet portion covering the other surface, and an outer surface of the first sheet portion and an inner surface of the second sheet portion are A power storage device having an adhesive portion bonded with an adhesive tape. The first electrode is provided with a current collecting tab so as to protrude from one end,
The power storage device according to claim 1, wherein the adhesive portion is located on one end side where the current collecting tab protrudes.   The power storage device according to claim 2, wherein the current collecting tab is bonded with the adhesive tape together with the first sheet portion and the second sheet portion.   The power storage device according to any one of claims 1 to 3, wherein the separator is configured such that the first sheet portion and the second sheet portion are connected by a folded portion. The first sheet portion has a short length from the side forming the folded portion to the opposite side with respect to the second sheet portion,
The power storage device according to claim 4, wherein the adhesive portion is located along the opposite side of the first sheet portion. The first electrode is a positive electrode having a positive electrode active material layer obtained by applying a positive electrode active material to a positive electrode metal foil,
The second electrode is a negative electrode having a negative electrode active material layer obtained by applying a negative electrode active material to a negative electrode metal foil,
The power storage device according to any one of claims 1 to 5, wherein a coating region of the positive electrode active material in the positive electrode is smaller than a coating region of the negative electrode active material in the negative electrode.   The power storage device according to any one of claims 1 to 6, wherein the separator is coated with ceramic.   The power storage device according to any one of claims 1 to 7, wherein the power storage device is a secondary battery.