JP6107539B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device.

  Conventionally, a power storage device such as a secondary battery includes an electrode assembly in which an electrode having an active material layer is stacked via a separator, and a case in which the electrode assembly is accommodated. Patent Document 1 describes a power storage device that includes an insulating sheet that insulates an electrode assembly from a case, and an intervening sheet that is interposed between the insulating sheet and the electrode assembly. Specifically, the electrode assembly has a pair of laminated surfaces perpendicular to the electrode lamination direction, and an intervening sheet is disposed between one laminated surface of the pair of laminated surfaces and the insulating sheet. Another intervening sheet is disposed between the other laminated surface and the insulating sheet. These intervening sheets prevent a gap from being formed between the laminated surface of the electrode assembly and the case.

JP 2009-48966 A

  Here, the present inventors intervene between the number of interposing sheets interposed between one laminated surface of the electrode assembly and the insulating sheet and between the other laminated surface and the insulating sheet. It has been found that when the number of intervening sheets is different, the electrode assembly may have a portion that tends to be locally degraded. Specifically, when the number of stacked layers is different, the inventors tend to accumulate heat on the side where the number of stacked layers in the electrode assembly is large, and as a result, the side where the number of stacked layers in the electrode assembly is large is deteriorated. I found it easy to do.

  The object of the present invention has been made in view of the above-described circumstances, and local deterioration of the electrode assembly is likely to occur while suppressing the generation of a gap between the laminated surface of the electrode assembly and the case. An object of the present invention is to provide a power storage device that can suppress the occurrence of a portion.

A power storage device that achieves the above object includes an electrode assembly in which an electrode having an active material layer is stacked via a separator, a case in which the electrode assembly is accommodated, and the electrode assembly and the case are insulated. an insulating sheet covering the electrode assembly be one that, an insulator, and includes a through the standing sheet you interposed between the electrode assembly and the insulating sheet, the electrode assembly Has a pair of laminated surfaces orthogonal to the lamination direction of the electrodes, the interposition sheet is bent and disposed across the pair of laminated surfaces, and the one laminated surface and the insulating sheet And between the other laminated surface and the insulating sheet, and the number of laminated intervening sheets interposed between the one laminated surface and the insulating sheet, Between the other laminated surface and the insulating sheet. Identical Der the stacking number of the intervening sheet interposed is, the intervening sheet by the intervening sheet extending in a direction perpendicular to the stacking direction of the electrode is folded, and the one laminate surface The intervening sheet is laminated between the insulating sheets in the laminating direction of the electrodes, and the intervening sheet extending in a direction perpendicular to the laminating direction of the electrodes is folded, thereby A second interposition part in which the interposition sheet is laminated in the laminating direction of the electrodes between the other laminating surface and the insulating sheet, and a connection connecting the first interposition part and the second interposition part And a single long shape having a portion .

  According to such a configuration, the number of intervening sheets laminated between one laminated surface and the insulating sheet, and the number of laminated interposing sheets interposed between the other laminated surface and the insulating sheet are: Since they are the same, it is possible to suppress a bias in heat transfer generated in the electrode assembly. For example, if the electrode assembly generates heat, the difference between the heat radiation amount from one laminated surface and the heat radiation amount from the other laminated surface is small. Thereby, in an electrode assembly, it can suppress that the part which deteriorates easily due to locally small heat dissipation is produced.

Further, the intervening sheet is bent and arranged across the pair of laminated surfaces, and is interposed between one laminated surface and the insulating sheet and between the other laminated surface and the insulating sheet. Yes. As a result, the number of intervening sheets laminated between one laminated surface and the insulating sheet tends to be the same as the number of intervening sheets laminated between the other laminated surface and the insulating sheet. Therefore, more preferably, it is possible to suppress the occurrence of a portion that is likely to be locally deteriorated in the electrode assembly while suppressing the generation of a gap between the laminated surface of the electrode assembly and the case. Furthermore, according to the present configuration, a plurality of stacked layers can be realized using a single long intervening sheet.

  In the power storage device, the electrode assembly has a rectangular parallelepiped shape having the pair of stacked surfaces, and the interposed sheet is bent along the outer shape of the electrode assembly, It is good to interpose between the one lamination surface and the insulating sheet and between the other lamination surface and the insulating sheet via at least a part of the orthogonal surface. According to such a configuration, the interposed sheet is bent along the outer shape of the electrode assembly, and is interposed between the one laminated surface and the insulating sheet via at least a part of the surface orthogonal to the laminated surface in the electrode assembly. And between the other laminated surface and the insulating sheet. Thereby, in the rectangular parallelepiped electrode assembly, the above-described effects can be obtained.

  In the power storage device, the electrode assembly has a bottom surface facing the bottom surface of the case, and the interposition sheet is formed between the one laminated surface and the insulating sheet via the bottom surface of the electrode assembly. It is good to interpose between both and between the other lamination surface and the insulating sheet. According to this configuration, the bottom surface of the electrode assembly to which a load is easily applied is covered with the intervening sheet. Thereby, even if it is a case where the part which covers the bottom face of the electrode assembly in an insulating sheet with a load is torn, a short circuit with an electrode assembly and a case does not arise easily by an interposition sheet. Therefore, the electrode assembly and the case can be more suitably insulated. In addition, for example, in a configuration in which the thickness of the insulating sheet is sufficiently ensured so that the portion covering the bottom surface of the electrode assembly in the insulating sheet is not torn, the thickness of the insulating sheet can be reduced. . Thereby, the cost concerning an insulating sheet can be reduced.

  In the power storage device, the case may contain an electrolytic solution, and the insulating sheet may have a hole in a portion covering the bottom surface of the electrode assembly. According to such a configuration, the electrolytic solution is impregnated inside the insulating sheet through the holes. On the other hand, even if there are holes in the insulating sheet, the interposition sheet makes it difficult for the electrode assembly and the case to be short-circuited. Thereby, it can be made to impregnate electrolyte solution suitably, insulating an electrode assembly and a case.

About the said electrical storage apparatus, the said interposition sheet | seat and the said insulating sheet are good to be joined. According to such a configuration, since the interposition sheet and the insulating sheet are joined, it is possible to suppress these positional deviations .

  About the said electrical storage apparatus, it is good for the both ends of the longitudinal direction of the said interposition sheet | seat to be joined. According to such a configuration, since both end portions in the longitudinal direction of the interposition sheet are joined, it is easy to maintain the bending mode of the interposition sheet, such as the interposition portions stacked in a zigzag shape. Thereby, it is possible to suppress inconvenience due to the use of one long intervening sheet, that is, it is not possible to maintain the bending mode of the intervening sheet and to be disjoint.

  About the said electrical storage apparatus, it is good for the both ends of the longitudinal direction of the said interposition sheet | seats to be joined by the said connection part. According to such a configuration, even when wrinkles or thickness variations occur at the joints between both ends in the longitudinal direction of the interposition sheet, these effects hardly affect the electrical characteristics of the power storage device. Thereby, the various influence resulting from joining the both ends of the longitudinal direction of an interposition sheet can be suppressed.

  The power storage device may be a secondary battery.

  According to the present invention, it is possible to suppress the occurrence of a portion that is likely to be locally deteriorated in the electrode assembly while suppressing the generation of a gap between the laminated surface of the electrode assembly and the case.

The perspective view which shows the external shape of a secondary battery. The exploded perspective view of an electrode assembly. The exploded perspective view of a secondary battery. FIG. 4 is a sectional view taken along line 4-4 of FIG. The perspective view which shows an electrode assembly and an interposition sheet. The front view which shows the state which the insulation sheet and the interposition sheet expand | deployed. The perspective view which shows the insertion process to the case of the electrode assembly to which the insulating sheet and the interposition sheet were attached. Sectional drawing of the electrode assembly and interposition sheet of 2nd Embodiment. The perspective view which shows the interposition sheet | seat of another example. The front view which shows the state which the interposition sheet | seat of another example developed. Sectional drawing which shows the intervening sheet | seat of another example. Sectional drawing which shows the intervening sheet | seat of another example. The perspective view which shows the electrode assembly and interposition sheet | seat of another example.

Hereinafter, an embodiment of the power storage device will be described.
As shown in FIG. 1, a secondary battery 10 as a power storage device includes a rectangular parallelepiped case 11. The case 11 includes a bottomed box-shaped case main body 12 that opens upward, and a rectangular flat plate-shaped lid 13 that closes the opening of the case main body 12. The case 11 is made of metal, for example, and has a predetermined heat capacity.

  The secondary battery 10 includes an electrode assembly 14 and an electrolytic solution 15 housed in a case 11, and a positive terminal 16 and a negative terminal 17 that exchange power with the electrode assembly 14. Each terminal 16, 17 is on the lid 13 of the case 11 and is arranged in a state of penetrating the lid 13. In addition, the secondary battery 10 of this embodiment is a lithium ion battery, for example.

  As shown in FIG. 2, the electrode assembly 14 has a structure in which positive electrodes 21 and negative electrodes 22 are alternately stacked via separators 23, which are porous membranes through which ions related to electric conduction can pass. Yes. Each of the electrodes 21 and 22 and the separator 23 is a rectangular sheet.

  The positive electrode 21 includes a rectangular positive metal foil (for example, an aluminum foil) 21a and positive electrode active material layers 21b on both surfaces of the positive metal foil 21a. The negative electrode 22 includes a rectangular negative metal foil (for example, copper foil) 22a and negative electrode active material layers 22b on both surfaces of the negative metal foil 22a. In the state constituting the electrode assembly 14, the positive electrode active material layer 21 b is covered with the negative electrode active material layer 22 b, and the electrodes 21 and 22 are covered with the separator 23.

  As shown in FIG. 2, the positive electrode 21 has a positive electrode tab 31 having a shape protruding from the end 21c. Similarly, the negative electrode 22 has a negative electrode tab 32 having a shape protruding from the end 22c. The electrodes 21 and 22 are stacked so that the same polarities of the tabs 31 and 32 are arranged in a row. As shown in FIG. 3, the negative electrode tabs 32 are gathered together in one of the stacking directions Y of the electrodes 21, 22 and folded back to the other in the gathered state. Similarly, each positive electrode tab 31 is folded back to the other side in a state where the positive electrode tabs 31 are gathered toward one side in the stacking direction Y of the electrodes 21 and 22.

  As shown in FIG. 3, the electrode assembly 14 has a rectangular parallelepiped shape. Here, on the outer periphery of the electrode assembly 14, the surfaces orthogonal to the stacking direction Y of the electrodes 21 and 22 are the stacked surfaces 14 b and 14 c, and the surface opposite to the top surface 14 a is the bottom surface 14 d. Furthermore, on the outer periphery of the electrode assembly 14, surfaces parallel to both the facing direction Z of the upper surface 14a and the bottom surface 14d and the stacking direction Y of the electrodes 21 and 22 are defined as side surfaces 14e and 14f. A direction perpendicular to both the facing direction Z and the stacking direction Y of the electrodes 21 and 22 is defined as a width direction X of the electrode assembly 14.

  The electrode assembly 14 is accommodated in the case 11 with the bottom surface 14d opposite to the top surface 14a on which the tabs 31 and 32 are located facing the bottom surface 11a of the case 11. The bottom surface 11 a of the case 11 is a surface opposite to the surface on which the terminals 16 and 17 are arranged, and is a surface facing the lid 13. The bottom surface 14 d of the electrode assembly 14 is a surface facing the bottom surface 11 a of the case 11.

  As shown in FIG. 3, the secondary battery 10 includes a positive electrode conductive member 41 and a negative electrode conductive member 42 that electrically connect the same polarities of the tabs 31 and 32 and the terminals 16 and 17. Each of the conductive members 41 and 42 has a plate shape and is disposed between the lid 13 of the case 11 and the electrode assembly 14. The positive electrode conductive member 41 is bonded to both the positive electrode tab 31 and the positive electrode terminal 16. Similarly, the negative electrode conductive member 42 is bonded to both the negative electrode tab 32 and the negative electrode terminal 17. As a joining mode, for example, welding is conceivable.

  As shown in FIGS. 3 and 4, the secondary battery 10 includes an insulating sheet 50 that insulates the electrode assembly 14 from the case 11. The insulating sheet 50 has, for example, a box shape opened upward by bending a single rectangular resin sheet. The insulating sheet 50 includes laminated surface covering portions 51 and 52 that cover the laminated surfaces 14b and 14c of the electrode assembly 14, a bottom surface covering portion 53 that covers the bottom surface 14d of the electrode assembly 14, and side surfaces 14e and 14f of the electrode assembly 14. And side surface covering portions 54 and 55 that cover the surface. Further, a part of the insulating sheet 50 protrudes above the upper surface 14 a of the electrode assembly 14.

  The secondary battery 10 is an insulator, and includes an interposition sheet 60 interposed between the insulating sheet 50 and the electrode assembly 14. There are a plurality of intervening sheets 60, two in the present embodiment, and each intervening sheet 60 has the same shape. The intervening sheet 60 is, for example, a rectangular resin sheet that can be bent. In addition, the thickness of the interposition sheet 60 is thinner than the thickness of the insulating sheet 50.

  As shown in FIG. 4, the intervening sheet 60 is bent and disposed across the pair of laminated surfaces 14 b and 14 c, and between the one laminated surface 14 b and the insulating sheet 50 and the other laminated surface 14 c. And the insulating sheet 50. Specifically, the interposition sheet 60 is bent along the outer shape of the electrode assembly 14, and between the one laminated surface 14 b and the one laminated surface covering portion 51 via the bottom surface 14 d of the electrode assembly 14, And it is interposed between the other laminated surface 14c and the other laminated surface covering portion 52. In this case, the interposition sheet 60 is U-shaped when viewed from the width direction X of the electrode assembly 14.

  In the following description, a portion interposed between one laminated surface 14b and one laminated surface covering portion 51 in the intervening sheet 60 is referred to as a first intervening portion 61, and the other laminated surface in the intervening sheet 60. A portion interposed between 14 c and the other laminated surface covering portion 52 is referred to as a second interposed portion 62. And the site | part which has connected both the interposition parts 61 and 62 in the interposition sheet 60 is called the connection part 63. FIG. The connection part 63 is continuous with both the interposition parts 61 and 62.

  Here, the number of interposing sheets 60 interposed between the one laminated surface 14b and the insulating sheet 50 and the interposing sheet 60 laminated between the other laminated surface 14c and the insulating sheet 50 are stacked. The number is the same. Specifically, the number of both laminated sheets is “2” because there are two intervening sheets 60. In the present embodiment, the number of intervening sheets 60 and the number of stacked sheets are the same.

  In addition, because the number of both layers is the same, the thickness D1 of the assembly of the first interposed portions 61, which is the length in the stacking direction Y of the electrodes 21 and 22 in the assembly of the first interposed portions 61, The thickness D2 of the assembly of the second interposition portions 62, which is the length in the stacking direction Y of the electrodes 21, 22 in the assembly of the second interposition portions 62, is the same.

  Incidentally, the number of both layers varies depending on the distance between the stacked surfaces 14 b and 14 c of the electrode assembly 14 and the case 11. Specifically, the number of both layers increases as the distance increases. Note that the number of both stacked layers is, for example, the length in the stacking direction Y of the electrodes 21 and 22 of the unit composed of the electrode assembly 14, the insulating sheet 50 and the intervening sheet 60 in the situation outside the case 11. The distance between the inner surfaces of the case 11 in the stacking direction Y may be set to be the same as or slightly larger than that.

  As shown in FIG. 5, the interposition sheet 60 covers the laminated surfaces 14 b and 14 c and the bottom surface 14 d of the electrode assembly 14. In this case, the first interposition part 61 covering the one laminated surface 14b is slightly larger than the one laminated surface 14b and covers the entire one laminated surface 14b. A part of the first interposition part 61 protrudes upward and in the width direction X of the electrode assembly 14 with respect to the one laminated surface 14 b of the electrode assembly 14. In addition, since the 2nd interposition part 62 is the same shape as the 1st interposition part 61, the detailed description is abbreviate | omitted. Further, the connection portion 63 of the interposition sheet 60 covers the entire bottom surface 14 d of the electrode assembly 14.

  In a state where the electrode assembly 14 covered with the insulating sheet 50 and the interposition sheet 60 is accommodated in the case 11, the insulating sheet 50 and the interposition sheet 60 are formed on the laminated surfaces 14 b and 14 c of the electrode assembly 14 and the case 11. It is sandwiched between. A pressing force is applied to the stacked surfaces 14 b and 14 c of the electrode assembly 14 from the stacking direction Y of the electrodes 21 and 22.

  Here, as shown in FIGS. 4 and 5, in the secondary battery 10, the plurality of interposed sheets 60 and the interposed sheet 60 that constitutes the outermost layer among the plurality of interposed sheets 60 and the insulating sheet 50 are joined. The joining part 70 is provided. The joint portion 70 is disposed at a position that does not overlap the electrode assembly 14 when viewed from the stacking direction Y of the electrodes 21 and 22. Specifically, the joint portion 70 is disposed in a portion of the first interposition portion 61 that protrudes above the one laminated surface 14 b of the electrode assembly 14, and extends in the width direction X of the electrode assembly 14. Exists. In addition, although it is arbitrary as a joining aspect, welding etc. can be considered, for example. In addition, it is not restricted to welding, You may join with an adhesive agent.

Next, an assembly process of the insulating sheet 50 and the interposition sheet 60 and an insertion process of the electrode assembly 14 which are a part of the manufacturing method of the secondary battery 10 will be described.
As shown in FIG. 6, first, a plurality of deployed intervening sheets 60 are installed on the deployed insulating sheet 50. In the present embodiment, the length in the longitudinal direction of the insulating sheet 50 is the same as the length in the longitudinal direction of the intervening sheet 60, and each intervening sheet 60 has an end in the longitudinal direction in the longitudinal direction of the insulating sheet 50. It is installed to match the end of And the end part of the longitudinal direction of each interposition sheet 60 and the insulating sheet 50 is welded collectively.

  Thereafter, the electrode assembly 14 is installed so that the bottom surface 14d of the electrode assembly 14 and the connecting portion 63 of the interposition sheet 60 abut. The welded interposition sheet 60 and insulating sheet 50 are bent along the outer shape of the electrode assembly 14. Specifically, the integrated insulating sheet 50 and intervening sheet 60 are bent along the boundary line B between the laminated surface covering portions 51 and 52 and the bottom surface covering portion 53.

  Here, as shown in FIG. 6, the side cover portions 54 and 55 in the insulating sheet 50 have cut portions C along the boundary line B. The insulating sheet 50 has a box shape by sequentially bending the parts of the side surface covering portions 54 and 55 divided by the cut portion C.

  Then, as shown in FIG. 7, the electrode assembly 14 covered with the interposition sheet 60 and the insulating sheet 50 is inserted so that the bottom surface 14 d faces the bottom surface 11 a of the case 11. In this case, the bottom surface covering portion 53 of the insulating sheet 50 and the connecting portion 63 of the interposing sheet 60 are sandwiched between the bottom surface 14 d of the electrode assembly 14 and the bottom surface 11 a of the case 11. Thereafter, the lid 13 is attached, and the electrolytic solution 15 is injected from a liquid injection hole (not shown) existing in the lid 13 to perform various processes.

Next, the operation of this embodiment will be described.
Since there are a plurality of intervening sheets 60 interposed between both the laminated surfaces 14 b and 14 c and the insulating sheet 50, a gap is hardly generated between the laminated surfaces 14 b and 14 c of the electrode assembly 14 and the case 11. That is, the thickness of the unit composed of the electrode assembly 14, the insulating sheet 50, and the interposed sheet 60, specifically the length in the stacking direction Y of the electrodes 21 and 22, is adjusted by the plurality of interposed sheets 60.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) The secondary battery 10 includes an interposition sheet 60 interposed between the insulating sheet 50 and the electrode assembly 14, and the interposition sheet 60 is folded and disposed across the pair of laminated surfaces 14b and 14c. It is interposed between the one laminated surface 14b and the one laminated surface covering portion 51 and between the other laminated surface 14c and the other laminated surface covering portion 52. Thereby, the interposition sheet between the one laminated surface 14b and the one laminated surface covering portion 51 and the intervening sheet between the other laminated surface 14c and the other laminated surface covering portion 52 are separated. Compared to a certain configuration, the number of intervening sheets required for adjusting the thickness of the unit can be halved. Here, when it is a separate body as described above, the positioning of each intervening sheet with respect to the insulating sheet 50 tends to be complicated due to an increase in the number of intervening sheets. Further, the intervening sheet interposed between the one laminated surface 14b and the one laminated surface covering portion 51 is different from the interposed sheet interposed between the other laminated surface 14c and the other laminated surface covering portion 52. Since it is necessary to arrange at a position, the positioning operation tends to be complicated. On the other hand, in this embodiment, since the above inconveniences can be suppressed, the process of installing the interposition sheet 60 on the insulating sheet 50 can be shortened, and productivity can be improved. it can.

  In addition, the number of intervening sheets 60 interposed between the one laminated surface 14b and the insulating sheet 50 (hereinafter also referred to as the first laminated number) and the other laminated surface 14c and the insulating sheet 50 are interposed. The number of intervening sheets 60 stacked (hereinafter also referred to as the second number of stacked sheets) is the same. Thereby, it can suppress that the part which deteriorates locally in the electrode assembly 14 arises, suppressing that a clearance gap produces between the lamination | stacking surfaces 14b and 14c of the electrode assembly 14, and the case 11. FIG.

  More specifically, if the first number of stacked layers is greater than the second number of stacked layers, the amount of heat released from one stacked surface 14b is smaller than that of the other stacked surface 14c. For this reason, heat tends to accumulate in a portion on the side of one laminated surface 14b, and as a result, the portion is likely to deteriorate. On the other hand, in this embodiment, since the number of both layers is the same, it is possible to suppress the bias of the heat dissipation amount as described above, and there is a portion that is likely to deteriorate due to the small amount of heat dissipation locally through it. It can be suppressed.

  In particular, since the intervening sheet 60 is bent and disposed across the pair of laminated surfaces 14b and 14c, the first laminated number and the second laminated number are naturally the same. Thereby, the situation that the number of both layers is different is unlikely to occur. Therefore, the number of both layers can be made the same without performing a special process for making the numbers of both layers the same, for example, counting and adjusting the number of both layers.

  (2) A load on the electrode assembly 14 or the like is easily applied to the bottom surface 14d of the electrode assembly 14 which is a surface facing the bottom surface 11a of the case 11. For this reason, the bottom surface covering portion 53 that covers the bottom surface 14 d of the electrode assembly 14 in the insulating sheet 50 is easily torn compared to the other covering portions 51, 52, 54, 55.

  On the other hand, in the present embodiment, the interposition sheet 60 is interposed between the one laminated surface 14b and the one laminated surface covering portion 51 via the bottom surface 14d of the electrode assembly 14, and the other laminated surface 14c. And the other laminated surface covering portion 52. Thereby, even if the bottom face covering portion 53 is torn, the electrode assembly 14 and the case 11 are not easily short-circuited by the intervening sheet 60. Therefore, the insulation between the electrode assembly 14 and the case 11 can be further improved. Further, for example, in a configuration in which the thickness of the insulating sheet 50 is sufficiently secured so that the insulating sheet 50 is not torn at the bottom surface 14d of the electrode assembly 14, the thickness of the insulating sheet 50 is reduced. be able to. Thereby, the cost concerning the insulating sheet 50 can be reduced.

  In particular, the rectangular insulating sheet 50 in which the cut portion C exists is folded into a box shape, and the box shape is easily realized as compared with a configuration in which a portion without the cut portion C is folded into a box shape. On the other hand, due to the cut portion C, the bottom surface 14d of the electrode assembly 14 may be exposed. In contrast, the interposition sheet 60 covers the bottom surface 14 d of the electrode assembly 14, thereby avoiding the above inconvenience. Thereby, coexistence with easy shaping of the insulating sheet 50 and suppression of the fall of the insulation of the electrode assembly 14 and the case 11 can be aimed at.

  (3) There are a plurality of intervening sheets 60, and the intervening sheets 60 are joined together. Thereby, since the some interposition sheet 60 is integrated, each interposition sheet 60 can be bent collectively, and the further improvement of productivity can be aimed at. In addition, it is possible to suppress misalignment between the intervening sheets 60.

  In particular, an intervening sheet interposed between one laminated surface 14b and one laminated surface covering portion 51, and an interposed sheet interposed between the other laminated surface 14c and the other laminated surface covering portion 52. When and are separate bodies, it is necessary to join them separately. That is, it is necessary that joint portions exist in both of the interposition portions 61 and 62. On the other hand, in the present embodiment, the single intervening sheet 60 is folded and disposed across the pair of laminated surfaces 14b and 14c, and therefore, the joining portion is one of the intervening portions 61 and 62. You only need to have one. For this reason, simplification of the process which concerns on joining can be achieved.

  (4) The outermost intermediate sheet 60 among the plurality of intermediate sheets 60, that is, the intermediate sheet 60 closest to the insulating sheet 50 and the insulating sheet 50 are joined. Thereby, since the interposition sheet 60 and the insulating sheet 50 are integrated, the insulating sheet 50 and the interposition sheet 60 can be bent together, and the productivity can be further improved. Moreover, the position shift of the insulating sheet 50 and the interposition sheet 60 can be suppressed.

  (5) The interposition sheets 60 and the joint portion 70 where the interposition sheet 60 and the insulating sheet 50 are joined exist in a portion protruding upward from the electrode assembly 14 in the first interposition portion 61. As a result, even when wrinkles or thickness variations occur around the joint 70, the influence is unlikely to affect the electrode assembly 14, specifically the active material layers 21 b and 22 b. Therefore, a location where a load is locally applied in a region where the active material layers 21b and 22b are opposed to each other due to various effects caused by the joint portion 70, for example, a decrease in battery reaction due to wrinkles and thickness variations. Can be suppressed.

(Second Embodiment)
In the present embodiment, the configuration of the interposed sheet is different from that of the first embodiment. The different points will be described below. In addition, about the same structure as 1st Embodiment, while attaching | subjecting the same code | symbol, the detailed description is abbreviate | omitted.

  As shown in FIG. 8, the interposition sheet 100 includes a first interposition part 101 laminated in a zigzag manner between one laminating surface 14 b and one laminating surface covering part 51 and the other laminating surface 14 c. And the other laminated surface covering portion 52 in a single elongated shape having a second interposition portion 102 laminated in a zigzag shape and a connection portion 103 connecting the interposition portions 101 and 102. is there.

  The first interposition part 101 is stacked in the stacking direction Y of the electrodes 21 and 22 in a state of being folded back in a zigzag manner. In this case, the folded portion of the first interposition part 101 is disposed at a position that does not overlap the electrode assembly 14 when viewed from the stacking direction Y of the electrodes 21 and 22. In addition, since the shape of the 2nd interposition part 102 is the same as that of the 1st interposition part 101, description is abbreviate | omitted. Incidentally, in the present embodiment, the number of first layers and the number of second layers are “4”.

  Here, both end portions 100 a and 100 b in the longitudinal direction of the interposition sheet 100 are disposed between the bottom surface 14 d of the electrode assembly 14 and the bottom surface covering portion 53, that is, at the connection portion 103. The both end portions 100 a and 100 b overlap each other at the connection portion 103, and are joined together with the connection portion 103 and the bottom surface covering portion 53. That is, the joint portion 104 of the present embodiment exists in the connection portion 103.

Next, the operation of this embodiment will be described.
The intervening portions 101 and 102 stacked in a zigzag manner realize the number of interposing sheets 60 of the intervening sheets 60 shown in the first embodiment.

According to this embodiment explained in full detail above, in addition to the effect of (1), (2), (4), there exist the following outstanding effects.
(6) The interposition sheet 100 includes a first interposition portion 101 that is laminated in a zigzag manner between the one laminated surface 14b and the one laminated surface covering portion 51, the other laminated surface 14c, and the other laminated surface. It is a single long shape having a second interposition part 102 that is laminated in a zigzag manner with the covering part 52 and a connection part 103 that connects the interposition parts 101 and 102. Thereby, a plurality of stacked layers can be realized with one intervening sheet 100. Accordingly, the number of intervening sheets 100 can be further reduced.

  Further, in the first embodiment, as the first stack number and the second stack number, that is, the number of intervening sheets 60 increases, the electrode assembly 14 is interposed between the bottom surface 14 d of the electrode assembly 14 and the bottom surface covering portion 53 of the insulating sheet 50. Since the number of interposing sheets 60 is increased, there is a concern about an increase in dead space. On the other hand, in this embodiment, regardless of the number of first layers and the number of second layers, the lamination of the interposition sheet 100 interposed between the bottom surface 14d of the electrode assembly 14 and the bottom surface covering portion 53 of the insulating sheet 50. The number is constant. Thereby, the expansion of the dead space accompanying the increase in the number of first layers and the number of second layers can be suppressed.

  (7) Both ends 100a, 100b in the longitudinal direction of the intervening sheet 100 are joined. Thereby, the bending aspect of each interposition part 101,102 laminated | stacked in zigzag form is easy to be hold | maintained. Thereby, it is possible to suppress inconvenience due to the use of a single long intervening sheet 100, that is, a situation in which the bending mode of the intervening sheet 100 cannot be maintained, and the intervening sheet 100 is not separated.

  (8) Particularly, both end portions 100 a and 100 b in the longitudinal direction of the interposition sheet 100 are joined at the connection portion 103. That is, the joint portion 104 where the both end portions 100 a and 100 b in the longitudinal direction of the interposition sheet 100 are joined exists in the connection portion 103. As a result, for example, various effects caused by the joint 104, such as wrinkles and thickness variations, can be suppressed.

  (9) The folded portions of the interposition portions 101 and 102 stacked in a zigzag shape are arranged at positions that do not overlap the electrode assembly 14 when viewed from the stacking direction Y of the electrodes 21 and 22. Thereby, even if it is a case where the return | turnback part is locally thick, it can suppress that a load is locally provided with respect to the electrode assembly 14. FIG.

In addition, you may change each said embodiment as follows.
As shown in FIG. 9, the intervening sheet 110 may be disposed across the pair of stacked surfaces 14 b and 14 c via a part of the upper surface 14 a instead of the bottom surface 14 d of the electrode assembly 14. In this case, the connection portion 113 of the intervening sheet 110 may cover the upper surface 14 a of the electrode assembly 14 together with the tabs 31 and 32 and the conductive members 41 and 42. As shown in FIG. 10, the intervening sheet 110 in this different example has a rectangular shape with a recess 114 in a part in the unfolded state, and the length of the connecting portion 113 is interposed in the short direction of the intervening sheet 110. It is shorter than the length of the parts 111 and 112. Then, the interposition sheet 110 is installed so that the connection portion 113 and the upper surface 14a of the electrode assembly 14 face each other, and is bent at the boundary line B so as to cover both the laminated surfaces 14b and 14c. Thereby, the interposition sheet | seat 110 can be attached without interfering with each terminal 16 and 17. FIG.

  The intervening sheet is not limited to the upper surface 14a of the electrode assembly 14, and the laminated surfaces 14b and 14c and the laminated surface covering portion 51, for example, via either one of the both side surfaces 14e and 14f of the electrode assembly 14. 52 may be interposed. In short, the intervening sheet may be interposed between the laminated surfaces 14b and 14c and the laminated surface covering portions 51 and 52 via at least a part of the surface of the electrode assembly 14 perpendicular to the laminated surfaces 14b and 14c. .

  As shown in FIG. 11, in the first embodiment, a hole 115 may exist in the bottom surface covering portion 53 of the insulating sheet 50. In this case, the electrolytic solution 15 is impregnated inside the insulating sheet 50 through the holes 115. Thereby, the electrolytic solution 15 is easily impregnated. On the other hand, since the interposition sheet 60 exists between the bottom surface 14d of the electrode assembly 14 and the bottom surface covering portion 53, insulation between the electrode assembly 14 and the case 11 is ensured. Thereby, the electrolytic solution 15 can be suitably impregnated while the electrode assembly 14 and the case 11 are insulated. The hole may be a part of the insulating sheet 50 cut out as described above, or may be defined by the edge of the insulating sheet 50.

  As shown in FIG. 12, in the second embodiment, the end portions 100a and 100b in the longitudinal direction of the interposition sheet 100 may be disposed in the interposition portions 101 and 102. In this case, both end portions 100a and 100b in the longitudinal direction of the intervening sheet 100 may not be joined, and the connecting portion 103 and the bottom surface covering portion 53 of the intervening sheet 100 may not be joined.

  O The magnitude relationship of the external shape of the positive electrode 21, the negative electrode 22, and the separator 23 is arbitrary. The positive electrode 21, the negative electrode 22, and the separator 23 may have the same shape, or the positive electrode 21 may be smaller than the negative electrode 22 and the negative electrode 22 may be smaller than the separator 23 in a front view.

  As long as the upper surface 14a, both side surfaces 14e and 14f, and the bottom surface 14d of the electrode assembly 14 are constituted by the positive electrode 21, the negative electrode 22, and the end face of the separator 23, they may be flush or uneven. It may be a shape. For example, when the positive electrode 21, the negative electrode 22, and the separator 23 have the same shape, the upper surface 14a, the side surfaces 14e and 14f, and the bottom surface 14d are flush with each other. On the other hand, when the positive electrode 21, the negative electrode 22, and the separator 23 are not the same shape, at least one of the upper surface 14a, the side surfaces 14e and 14f, and the bottom surface 14d has an uneven shape.

  The electrode assembly 14 has a plurality of positive electrodes 21 and a plurality of negative electrodes 22 and is a so-called stacked type in which the positive electrodes 21 and the negative electrodes 22 are alternately stacked, but is not limited thereto. For example, as shown in FIG. 13, the electrode assembly 120 is formed by laminating the electrodes 121 and 122 by winding the long positive electrode 121 and the negative electrode 122 through the long separator 123. It may be a wound type. In this case, the electrode assembly 120 includes a flat portion 131 having a pair of flat surfaces 131a and 131b facing each other, and the winding portion direction orthogonal to the flat shaft 131 and the opposing direction of the pair of flat surfaces 131a and 131b. And a curved portion 132 having a curved surface 132a. The electrode assembly 120 includes a top surface 120a on which the tabs 31 and 32 are present and a bottom surface 120b opposite to the top surface 120a as surfaces orthogonal to the winding axis direction. In such a configuration, the interposition sheet 140 is bent along the outer shape of the electrode assembly 120 and straddles both the flat surface 131a and the other flat surface 131b via the bottom surface 120b of the electrode assembly 120. It should be arranged.

  In addition, in the said other example, it replaces with the bottom face 120b of the electrode assembly 120, and the interposition sheet | seat 140 may be arrange | positioned ranging over the flat surfaces 131a and 131b via the curved surface 132a or the upper surface 120a.

  The bottom surface 11a of the case 11 is a surface opposite to the surface on which the terminals 16 and 17 are disposed and is a surface facing the lid 13, but is not limited to this, and either It may be a surface that satisfies the following conditions.

  In the first embodiment, there are a plurality of intervening sheets 60. However, the present invention is not limited to this, and a single sheet may be used. Moreover, you may use together the interposition sheet 60 of 1st Embodiment, and the interposition sheet which is not bent and intervenes only between the one lamination surface 14b and the one lamination surface coating | coated part 51. FIG. In short, it is only necessary that at least one of the plurality of interposed sheets is bent and interposed between the stacked surfaces 14b and 14c and the stacked surface covering portions 51 and 52.

  The intervening portions 61 and 62 cover the entire laminated surfaces 14b and 14c, but are not limited to this, and are configured to cover a part, for example, a region where the active material layers 21b and 22b face each other. May be. In short, the interposition portions 61 and 62 only need to be interposed at least partially between the laminated surfaces 14b and 14c and the laminated surface covering portions 51 and 52.

(Circle) the length of the longitudinal direction of the insulation sheet 50 of the expand | deployed state may be longer than the length of the longitudinal direction of the interposition sheet 60 of the expand | deployed state.
The thickness of the intervening sheet 60 is thinner than the thickness of the insulating sheet 50, but is not limited to this, and both may be the same, or the intervening sheet 60 may be thicker than the insulating sheet 50. May be.

  The joint portion 70 is disposed at a portion of the first interposition portion 61 that protrudes upward from the one laminated surface 14 b of the electrode assembly 14, but is not limited thereto, and the direction in which the electrodes 21 and 22 are laminated It suffices if it is disposed so as not to overlap with the positive electrode active material layer 21b as viewed from Y.

The joint part 70 may be in the second interposition part 62 instead of the first interposition part 61, or may be in both the first interposition part 61 and the second interposition part 62.
(Circle) the location where the interposition sheet 60 is joined, and the location where the interposition sheet 60 and the insulating sheet 50 are joined may differ. Further, the intervening sheets 60 may not be joined to each other, and the intervening sheet 60 and the insulating sheet 50 may not be joined.

The secondary battery 10 may be mounted on a vehicle and used for traveling, or may be used as a stationary power source.
The secondary battery 10 is a lithium ion 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 21b and the negative electrode active material layer 22b and transfer charges. Further, an electric double layer capacitor may be used as the power storage device.

  In 1st Embodiment, although the interposition sheet 60 was arrange | positioned between the lamination | stacking surfaces 14b and 14c of the electrode assembly 14, and the lamination | stacking surface coating | coated parts 51 and 52 of the insulating sheet 50, it is not restricted to this. For example, the interposition sheet may be configured to intervene between the insulating sheet 50 and the case 11. Specifically, the intervening sheet is folded and disposed across the pair of laminated surface covering portions 51, 52, and between the one laminated surface covering portion 51 and the case 11 and the other laminated surface covering portion. 52 may be interposed between the case 52 and the case 11. Even in this case, the effect (1) is obtained.

  In the second embodiment, the interposition portions 101 and 102 are stacked in a zigzag shape, but the present invention is not limited to this, and may be a spiral shape. Even in this case, a plurality of stacked layers can be realized by one intervening sheet 100.

Next, a preferable example that can be grasped from the embodiment and another example will be described below.
(A) The electrode assembly is a flat wound type in which electrodes are stacked by winding the electrode through a separator, and a flat portion having a pair of flat surfaces facing each other, and a flat portion On the other hand, it is present on both sides in a direction orthogonal to both the winding axis direction and the opposing direction of the pair of flat surfaces, and has a curved portion having a curved surface, and the interposition sheet is provided with the electrode assembly. Between the flat surface and the insulating sheet, and between the flat surface and the insulating sheet via a curved surface or a surface orthogonal to the winding axis direction of the electrode assembly, which is bent along the outer shape. It is good to intervene in both.

  (B) In a power storage device comprising an electrode assembly in which an electrode having an active material layer is stacked via a separator, and a case in which the electrode assembly is accommodated, the electrode assembly and the case are insulated And an insulating sheet that covers the electrode assembly, and one or a plurality of intervening sheets that are an insulator and are interposed between the insulating sheet and the case, and the electrode assembly is arranged in the stacking direction of the electrodes The insulating sheet has a pair of covering portions that cover the pair of stacked surfaces, and the interposition sheet is bent and disposed across the pair of covering portions, Between the covering portion and the case, and between the other covering portion and the case, the number of interposing sheets interposed between the one covering portion and the case, and the other Product of intervening sheets interposed between the cover and the case May is a power storage device, characterized in that the number is the same.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery (electric storage apparatus), 11 ... Case, 11a ... Bottom surface of case, 14 ... Electrode assembly, 14b, 14c ... Laminated surface of electrode assembly, 14d ... Bottom surface of electrode assembly, 15 ... Electrolyte, 21, 22 ... Electrodes, 23 ... Separator, 50 ... Insulating sheet, 60 ... Interposing sheet, 100 ... Interposing sheet of the second embodiment, 100a, 100b ... Both ends of the interposing sheet, 101 ... First interposing portion, 102 ... First 2 interposition part, 103 ... connection part, 115 ... hole.

Claims (8)

An electrode assembly in which an electrode having an active material layer is laminated via a separator;
A case in which the electrode assembly is accommodated;
In a power storage device comprising:
An insulating sheet that insulates the electrode assembly and the case and covers the electrode assembly;
An insulator, and includes a through the standing sheet you interposed between the electrode assembly and the insulating sheet,
The electrode assembly has a pair of lamination surfaces orthogonal to the lamination direction of the electrodes,
The intervening sheet is bent and arranged across the pair of laminated surfaces, both between the one laminated surface and the insulating sheet, and between the other laminated surface and the insulating sheet. Intervening in
The number of laminated sheets interposed between the one laminated surface and the insulating sheet, and the number of laminated intermediate sheets interposed between the other laminated surface and the insulating sheet the same der is,
The interposition sheet is
When the interposition sheet extending in a direction orthogonal to the electrode stacking direction is folded back, the interposition sheet is stacked in the electrode stacking direction between the one stacking surface and the insulating sheet. 1 intervening part;
When the interposition sheet extending in a direction orthogonal to the electrode stacking direction is folded, the interposition sheet is stacked in the electrode stacking direction between the other stack surface and the insulating sheet. 2 intervening parts;
A connecting portion connecting the first interposed portion and the second interposed portion;
A power storage device, characterized in that the power storage device has a long shape . The electrode assembly has a rectangular parallelepiped shape having the pair of laminated surfaces,
The interposed sheet is bent along the outer shape of the electrode assembly, and is interposed between the one laminated surface and the insulating sheet via at least a part of a surface orthogonal to the laminated surface in the electrode assembly. The power storage device according to claim 1, wherein the power storage device is interposed between the other laminated surface and the insulating sheet. The electrode assembly has a bottom surface facing the bottom surface of the case,
The interposition sheet is interposed between the one laminated surface and the insulating sheet and between the other laminated surface and the insulating sheet via the bottom surface of the electrode assembly. The power storage device according to claim 2. The case contains an electrolytic solution,
The power storage device according to claim 3, wherein a portion of the insulating sheet that covers the bottom surface of the electrode assembly has a hole. The power storage device according to any one of claims 1 to 4 , wherein the interposition sheet and the insulating sheet are joined. The power storage device according to any one of claims 1 to 5, wherein both end portions in the longitudinal direction of the interposition sheet are joined to each other. The power storage device according to claim 6 , wherein both end portions in the longitudinal direction of the interposition sheet are joined at the connection portion. The power storage device according to any one of claims 1 to 7 , wherein the power storage device is a secondary battery.