JP6507612B2 - Storage element - Google Patents

Description

  The present invention relates to a storage element including a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery.

  A storage element including a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery may be provided with an electrode assembly formed by overlapping a positive electrode sheet and a negative electrode sheet with a separator interposed therebetween. The electrode assembly of this type is housed in an outer package comprising a case body and a lid for closing the opening of the case body.

  Patent Document 1 discloses a technology in which a spacer is interposed between the lower end surface of the electrode body and the bottom of the case body in this type of storage element. By arranging the spacer in this manner, it is possible to suppress the vibration and the shock transmitted from the outside of the exterior body to the electrode body.

JP, 2014-049303, A

  By the way, in the electrode body formed by superposing a plurality of sheets as described above, gas may be generated between the sheets. This gas flows from the end face portion of the electrode body to the internal space of the exterior body, and is discharged to the external space of the exterior body through a gas discharge unit such as a safety valve provided in the exterior body.

  However, when the end face of the electrode body is closed by the spacer as in the storage element of Patent Document 1, it becomes difficult to release the gas generated between the sheets of the electrode body from the end face. Therefore, there is a problem that it is difficult to discharge the gas to the outside of the outer package depending on various kinds of conditions such as the type, shape and posture of the electrode body and the arrangement of the gas discharge part in the outer package.

  For example, in the storage element of Patent Document 1, since the end face of the electrode body facing the bottom of the case main body is covered with the spacer, the gas generated between the sheets of the electrode body is released from the end face on the bottom side It becomes difficult to lead to the opening side of the case body. In addition, although the spacer which the center part opened is disclosed by patent document 1, since this opening part is block | closed by the bottom part of the case main body, the gas extraction from the bottom side end surface part of an electrode body is Have difficulty.

  Then, this invention makes it a subject to aim at the improvement of gas discharge performance in the electrical storage element which a spacer interposes between the end surface part of an electrode body, and the inner surface of an exterior body.

The present invention
An electrode body having a predetermined end face portion on which a plurality of sheets are stacked and an edge portion of the plurality of sheets is disposed;
An exterior body that has an opposing surface that faces the end surface, and that accommodates the electrode body;
A gas discharge part provided in a portion different from the facing surface part in the exterior body;
A spacer interposed between the end face and the opposing face so that a communication part communicated with the gas discharge part is formed between the end face and the opposing face; To provide a storage element.

  By interposing a spacer between the predetermined end face portion of the electrode body and the facing surface portion of the exterior body, it is possible to suppress the vibration and impact transmitted from the outside of the exterior body to the electrode body. Further, the communication portion is formed between the end face portion of the electrode body and the facing surface portion of the exterior body, whereby the gas generated between the plurality of sheets in the electrode body is provided in the communication portion and the exterior body. The gas can be favorably discharged to the outside of the outer package through the gas discharge unit.

  According to the storage element of the present invention, it is possible to improve the gas discharge performance of the storage element while suppressing the vibration and the shock transmitted to the electrode body from the outside of the exterior body.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view of the non-aqueous electrolyte secondary battery which concerns on 1st Embodiment of this invention. The disassembled perspective view of the non-aqueous electrolyte secondary battery of FIG. The perspective view of an electrode body. The expanded view of an electrode body. The enlarged view of the part V of FIG. The enlarged view of the part VI of FIG. FIG. 2 is a perspective view of an electrode body and a current collector. The partially broken partial perspective view of the nonaqueous electrolyte secondary battery of FIG. FIG. 2 is a partially broken exploded side view of the non-aqueous electrolyte secondary battery of FIG. 1; 1. XX sectional drawing of FIG. 1 which looked at the inside of the nonaqueous electrolyte secondary battery of FIG. 1 from the bottom side. The cross-sectional view similar to FIG. 10 which shows the modification of a bottom part spacer. FIG. 11 is a cross-sectional view similar to FIG. 10 showing another variation of the bottom spacer; The disassembled perspective view of the non-aqueous electrolyte secondary battery which concerns on 2nd Embodiment of this invention. The perspective view which looked the insulation sheet from diagonally downward. FIG. 14 is a cross-sectional view similar to FIG. 10, showing the inside of the nonaqueous electrolyte secondary battery of FIG. 13 viewed from the bottom side. The perspective view of the insulation sheet of the nonaqueous electrolyte secondary battery concerning a 3rd embodiment of the present invention. FIG. 18 is a cross-sectional view similar to FIG. 15 showing the inside of the non-aqueous electrolyte secondary battery provided with the insulating sheet of FIG. 17 viewed from the bottom side. The perspective view of the insulating sheet of the nonaqueous electrolyte secondary battery which concerns on 4th Embodiment of this invention.

  Hereinafter, an embodiment according to the present invention will be described according to the attached drawings. In the following description, terms that indicate specific directions or positions (for example, terms including “upper”, “lower”, “side”, and “end”) are used as needed, but the use of those terms Is for facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. Also, the following description is merely exemplary in nature and is not intended to limit the present invention, its applications, or its applications.

First Embodiment
FIG. 1 and FIG. 2 show a lithium ion secondary battery (hereinafter simply referred to as “battery”) 1 according to a first embodiment of the present invention.

[overall structure]
Referring to FIGS. 1 and 2, the battery 1 includes an outer package 10, an electrode assembly 20, a bottom spacer 40, positive and negative external terminals 50A and 50B, positive and negative current collectors 60A and 60B, and upper packings 70A and 70B, Lower packing 80A, 80B and upper spacer 90 are provided.

  The exterior body 10 includes a case body 11 and a lid 12 closing the opening 11 a of the case body 11. In the present embodiment, the case body 11 and the lid 12 are made of aluminum or an aluminum alloy. The case main body 11 includes a substantially rectangular plate-like bottom wall 11b and a rectangular cylindrical portion 11z rising from the periphery of the bottom wall 11b. The rectangular cylindrical portion 11z includes a pair of long side walls 11c rising from the long side of the bottom wall 11b and a pair of short side walls 11d rising from the short side of the bottom wall 11b. The lid 12 is generally in the form of a rectangular plate. The upper ends of the long side wall 11 c and the short side wall 11 b define an opening 11 a of the case body 11. The electrode body 20 is accommodated in the case main body 11 filled with the electrolytic solution. A bottom spacer 40 is interposed between the electrode body 20 and the bottom wall 11 b of the case body 11. The lower packings 80A and 80B and the upper spacer 90 are also accommodated in the case body 11. The lid 12 is provided with a safety valve 13 as a gas discharge unit that discharges the gas generated in the case body 11 to the outside of the exterior body 10.

  Referring to FIG. 3 and FIG. 4 together, the electrode body 20 is a strip 23 of a positive electrode sheet 21, a negative electrode sheet 22 and a microporous resin sheet, both of which are long strips having a constant width. 23 is superimposed and wound into a long oval shape having a high flatness. One of the two separators 23 is interposed between one layer of the positive electrode sheet 21 and one layer of the negative electrode sheet 22 adjacent thereto. The axis (winding axis) of the winding of the positive electrode sheet 21, the negative electrode sheet 22 and the two separators 23 and 23 is conceptually shown by a symbol A in FIG. 3. The electrode body 20 has a posture in which the winding axis A is disposed substantially along the direction in which the rectangular cylindrical portion 11z of the case body 11 extends, that is, the direction in which the bottom wall 11b of the case body 11 and the opening 11a face each other It is accommodated in the case main body 11 in a posture extending in the vertical direction in FIG.

  As shown in FIG. 3, each end of the electrode body 20 in the direction in which the winding axis A extends is an end face where the widthwise edges of the positive electrode sheet 21, the negative electrode sheet 22, and the separators 23 and 23 are disposed. It is 20a, 20b. The electrode body 20 is disposed opposite to each other with the winding axis A interposed therebetween, and from the extending direction of the winding axis A, a pair of straight portions 20c and 20c linearly extending parallel to each other when viewed from the extending direction of the winding axis A It has a pair of curved portions 20d, 20d extending to connect the pair of straight portions 20c, 20c while curving in a semicircular shape as viewed.

  The straight portion 20c is a portion extending linearly in design. In a state in which the electrode body 20 is actually accommodated in the exterior body 10, the linear portion 20c is not always disposed in a completely linear shape, and is in a state of being bent so as to have a nearly linear shape as a whole. It may be arranged by

  The positive electrode sheet 21 includes a strip-shaped positive electrode metal foil 24 and a positive electrode active material layer 25 formed on both sides of the positive electrode metal foil 24. The positive electrode active material layer 25 is provided up to the side edge of the positive electrode metal foil 24 at one end (lower side in FIGS. 3 and 4) of the positive electrode sheet 21 in the width direction. At the other end (upper side in FIGS. 3 and 4) of the width direction of the positive electrode sheet 21, an uncoated portion 24 a in which the positive electrode metal foil 24 is exposed is provided without providing the positive electrode active material layer 25. ing. The width of the negative electrode sheet 22 is larger than the width of the positive electrode sheet 21, and the width of the separator 23 is larger than the width of the negative electrode sheet 22.

  The negative electrode sheet 22 includes a strip-shaped negative electrode metal foil 26 and a negative electrode active material layer 27 formed on both sides of the negative electrode metal foil 26. The negative electrode active material layer 27 is provided up to the side edge of the negative electrode metal foil 26 at one end (lower side in FIGS. 3 and 4) of the negative electrode sheet 22 in the width direction. At the other end (upper side in FIGS. 3 and 4) of the width direction of the negative electrode sheet 22, an uncoated portion 26 a is provided in which the negative electrode metal foil 26 is exposed without providing the negative electrode active material layer 27. ing.

  The positive electrode metal foil 24 is provided with a plurality of protrusions 24 b protruding outward in the width direction from the uncoated portion 24 a at intervals in the longitudinal direction. In a state in which the positive electrode sheet 21, the negative electrode sheet 22, and the separators 23 and 23 are wound in an overlapping manner, a plurality of projections 24 b are overlapped with each other to form a tab-like portion (positive current collection tab 28) projecting from the electrode body 20. Form). The negative electrode metal foil 26 is also provided with a plurality of projections 26b similar to the projections 24b of the positive electrode metal foil 24. These projections 26b are superimposed on one another, so that the negative electrode current collector protrudes from the electrode body 20. Tabs 29 are formed.

  Referring to FIG. 3, the positive electrode current collection tab 28 and the negative electrode current collection tab 29 protrude from one end 20 a (upper end in FIG. 3) of the electrode body 20. Further, with respect to the center line B in the longitudinal direction when the end portion 20a of the electrode body 20 is viewed from the direction in which the winding axis A extends, one side of the pair of straight portions 20c, 20c (the front side in FIG. 3) The positive electrode current collection tab 28 and the negative electrode current collection tab 29 project from the above.

  The positive electrode external terminal 50A is disposed on one end side (left side in FIG. 1) of the lid 12, and the negative electrode external terminal 50B is disposed on the other end side (right side in FIG. 1). The external terminals 50A and 50B include plate-like portions 51A and 51B disposed on the outer side surface (upper side surface) 12a of the lid 12. Connecting members such as bus bars are welded to the plate-like portions 51A and 51B and connected to an external circuit.

  Referring to FIG. 5 in addition to FIGS. 1 and 2, the positive electrode external terminal 50A has a plate-like portion 51A disposed on the outer surface 12a of the lid 12 and a cylindrical shape projecting downward from the lower surface of the plate-like portion 51A. The shaft portion 52 of The plate-like portion 51A and the shaft portion 52 are integrally formed. The shank 52 penetrates the lid 12 and protrudes into the case body 11.

  An enlarged diameter portion 52a is provided at the lower end of the shaft portion 52 of the positive electrode external terminal 50A, whereby the positive electrode external terminal 50A is crimped and fixed to the lid 12. Specifically, between the plate-like portion 51A of the external terminal 50A and the enlarged diameter portion 52a, the upper packing 70A made of insulating resin, the lid 12, the lower packing 80A made of insulating resin, and the current collector 60A of the positive electrode The external terminal 50A of the positive electrode and the current collector 60A are fixed to the lid 12 by sandwiching a portion to be crimped 62A) described later. An upper packing 70A is interposed between the outer side surface 12a of the lid 12 and the external terminal 50A, and a lower packing 80A is interposed between the inner side (lower side) 12b of the lid 12 and the current collector 60A. ing. In the present embodiment, the external terminal 50 of the positive electrode and the current collector 60A are made of aluminum or an aluminum alloy.

  Referring to FIG. 6 in addition to FIG. 1 and FIG. 2, the external terminal 50B of the negative electrode includes a plate-like portion 51B disposed on the outer surface 12a of the lid 12 and a rivet 53 separate from the plate-like portion 51B. . The jaw 53a at the upper end of the rivet 53 is press-fitted into the through hole formed in the plate-like portion 51B, whereby the rivet 53 is fixed to the plate-like portion 51B. The rivet 53 protrudes downward from the lower surface of the plate-like portion 51 B, penetrates the lid 12 and protrudes inside the case main body 11.

  An enlarged diameter portion 53 b is provided at the lower end of the rivet 53 of the external terminal 50 A of the negative electrode, whereby the external terminal 50 B of the negative electrode is crimped to the lid 12. Specifically, between the plate-like portion 51B of the external terminal 50B and the enlarged diameter portion 53b, the upper packing 70B made of insulating resin, the lid 12, the lower packing 80B made of insulating resin, and the current collector 60B of the negative electrode By being sandwiched, the external terminal 50B of the negative electrode and the current collector 60B are fixed to the lid 12. An upper packing 70B is interposed between the outer surface 12a of the lid 12 and the external terminal 50B, and a lower packing 80B is interposed between the inner surface 12b of the lid 12 and the current collector 60B of the negative electrode. In the present embodiment, the external terminal 50B of the negative electrode is made of the plate-like portion 51B of aluminum or aluminum alloy, and the rivet 53 is made of copper or copper alloy. The current collector 60B of the negative electrode is made of copper or a copper alloy.

  As most clearly shown in FIG. 7, the current collector 60A of the positive electrode includes a portion to be welded 61A and a portion to be crimped 62A. The welding portion 61A is welded to the positive electrode current collecting tab 28 of the electrode body 20, and is electrically and mechanically connected. As described above, the portion to be crimped 62A is crimped and fixed to the lid 12 by the enlarged diameter portion 52a formed on the shaft portion 52 of the external terminal 50A of the positive electrode. Similarly, the current collector 60B of the negative electrode includes a welded portion 61B and a crimped portion 62B. The welding portion 61 B is welded to the negative electrode current collecting tab 29 of the electrode body 20 so as to be electrically and mechanically connected. As described above, the crimped portion 62B is crimped to the lid 12 by the enlarged diameter portion 53b formed on the rivet 53 of the external terminal 50B of the negative electrode.

  As most clearly shown in FIGS. 8 and 9, an upper spacer 90 is interposed between the electrode body 20 and the inner side surface 12 b of the lid 12. The upper spacer 90 is provided with a current collector accommodating portion 92 for each of the current collectors 60A and 60B. The current collector housing 92 includes a side wall 92a, an upper wall 92b extending from the upper end of the side wall 92a, and a lower wall 92c extending generally in parallel with the upper wall 92b from the lower end of the side wall 92a. Between the upper wall 92b and the lower wall 92c, a gap 92d is formed open to the side opposite to the side wall 92a.

  As shown in FIG. 9, the current collector 60 </ b> A of the positive electrode is inserted into the gap 92 d of the current collector housing portion 92 together with the folded positive electrode current collection tab 28. Similarly, the current collector 60B of the negative electrode is inserted into the gap 92d of the current collector housing portion 92 together with the folded negative electrode current collection tab 29. Thus, the current collectors 60A and 60B are insulated from the lid 12 by the upper wall 92b of the upper spacer 90, and are insulated from the electrode body 20 by the lower wall 92c of the upper spacer 90.

Bottom spacer
Hereinafter, the bottom spacer 40 and the configuration related thereto will be described in detail.

  FIG. 10 is a cross-sectional view showing the internal structure of the battery 1 as viewed from the bottom side of the case body 11 (hereinafter simply referred to as the “bottom side”) in the direction in which the winding axis A (see FIG. 3) extends.

  As shown in FIG. 10, each linear portion 20 c of the electrode body 20 is disposed to face the long side wall portion 11 c of the case main body 11. Each curved portion 20 d of the electrode body 20 is disposed to face the short side wall portion 11 d of the case main body 11. The end face 20b of the electrode body 20 is disposed to face the bottom wall 11b of the case main body 11 via the bottom spacer 40 (see FIGS. 1 and 2).

  The outer peripheral surface 20e of the curved portion 20d of the electrode body 20 is semicircular when viewed from the direction in which the winding axis A (see FIG. 3) extends, and the case body 11 is substantially rectangular when viewed from the same direction. Therefore, a space S1 is formed between each curved portion 20d and each corner portion 11e of the short side wall portion 11d of the case main body 11 facing the curved portion 20d. The curved portion 20d is closest to the short side wall portion 11d at its top 20f. The top portion 20 f means a circumferential central portion of the outer peripheral surface 20 e of the curved portion 20 d. When viewed from the direction in which the winding axis A (see FIG. 3) extends, the top 20 f is disposed at the longitudinal end of the electrode body 20.

  The bottom spacer 40 is interposed between the end face 20 b and the bottom wall 11 b of the case main body 11 so as to support the end face 20 b of the electrode body 20 from the bottom side. Thereby, the vibration and the shock transmitted to the electrode body 20 from the outside of the case main body 11 are suppressed, and the electrode body 20 can be protected.

  The bottom spacer 40 is formed of a plate-like member. Although the material of the bottom spacer 40 is not limited, for example, a resin such as foamed polyphenylene ether (PPE) is used.

  The shape of the bottom spacer 40 viewed from the bottom side is a rectangular shape having a pair of long sides 40 a and a pair of short sides 40 c. When viewed from the bottom side, the longitudinal dimension of the bottom spacer 40 is smaller than the longitudinal dimension of the electrode body 20, and the outer shape of the bottom spacer 40 is smaller than the outer shape of the end face 20b of the electrode body 20.

  Each long side 40 a of the bottom spacer 40 is disposed along the long side wall 11 c of the case body 11. Each short side 40 c is disposed at an interval from the short side wall 11 d of the case main body 11. More specifically, each short side 40c is disposed along the boundary between the curved portion 20d and the straight portion 20c. The bottom spacers 40 arranged in this manner cover the pair of straight portions 20c of the electrode body 20, and the pair of curved portions 20d are opened.

  The space between the sheets 21, 22 and 23 (see FIG. 3) constituting the electrode assembly 20 is the bottom of the case 20 and the bottom of the case main body 11 by opening the respective curved parts 20d to the bottom side. The space S1 communicates with the space S1 between the bending portion 20d and the corner 11e of the case body 11 through the space between the wall 11b. The space S1 is formed to extend from the bottom side to the opening side along the corner portion 11e of the case main body 11, and a space between the lid 12 and the end face portion 20a of the electrode body 20 opposed thereto is interposed. And communicates with the safety valve 13 provided on the lid 12.

  Thus, the bottom spacer 40 is provided such that the curved portion 20 d is opened at the end surface 20 b on the bottom side of the electrode body 20, so that the curved portion 20 d of the end surface 20 b and the bottom wall 11 b of the case main body 11 In the meantime, the communication part 19 communicated with the safety valve 13 is formed (see FIG. 1). Thereby, the gas generated between the sheets 21, 22 and 23 of the electrode assembly 40 can be discharged from the end face 20 b to the communicating part 19. Since the gas discharged to the communication part 19 can rapidly flow to the safety valve 13 via the flow path including the space S1, the gas discharge from the safety valve 13 to the outside of the exterior body 10 can be promoted.

  As described above, according to the present embodiment, the vibration transmitted from the outside of the case body 11 to the electrode body 20 by the bottom spacer 40 interposed between the end face 20 b of the electrode body 20 and the bottom wall 11 b of the case body 11 By forming the communication portion 19 between the end face portion 20 b of the electrode body 20 and the bottom wall portion 11 b of the case main body 11 while suppressing the impact, the gas discharge performance of the battery 1 can be improved.

  However, in the first embodiment, the shape, size and arrangement of the bottom spacer 40 viewed from the bottom side are not limited to those shown in FIG. 10, and a part of the end face 20b of the electrode body 20 is a space S1. Various modifications are possible as long as it is configured to communicate with the

  For example, in the longitudinal direction of the bottom spacer 40, the bottom spacer 40 is disposed such that the short side 40c is disposed outside the boundary between the straight portion 20c and the curved portion 20d of the electrode body 20 and inside the top 20f. The longitudinal dimension may be extended. In this case, since a part of the curved portion 20d of the electrode body 20 is opened to the bottom side, communication between the end surface portion 20b of the electrode body 20 and the space S1 can be secured via the communication portion 19. Also, in this case, the extended bottom spacer 40 can support the electrode assembly 20 from the bottom side more stably.

  Conversely, the longitudinal dimension of the bottom spacer 40 is reduced such that the short side 40 c is disposed inward of the boundary between the straight portion 20 c and the curved portion 20 d of the electrode body 20 in the longitudinal direction of the bottom spacer 40. You may In this case, in addition to the curved portion 20d of the electrode body 20, a part of the straight portion 20c is also opened to the bottom side, so the communication portion 19 can be enlarged.

  Further, as in the bottom spacer 140 according to the modification shown in FIG. 11, a protrusion 141 may be provided which protrudes outward from the central portion of the short side 40c. In this case, the curved portion 20 d of the electrode body 20 can be supported from the bottom side by the projecting portion 141, and the curved portion 20 d of the electrode body 20 is opened to the bottom side on both sides sandwiching the projecting portion 141. Thus, communication between the end face 20b and the space S1 can be secured.

  Furthermore, as in the bottom spacer 160 according to the modification shown in FIG. 12, it is outside the boundary between the straight portion 20 c of the electrode body 20 and the curved portion 20 d and inside the top 20 f in the longitudinal direction of the bottom spacer 160. The short side 40 c may be disposed, and the recess 161 may be provided inward from the center of the short side 40 c. In this case, the curved portion 20d of the electrode body 20 can be supported from the bottom side by the extended portion of the bottom spacer 160, and the open portion of the end face portion 20b of the electrode body 20 and hence the communicating portion 19 can be enlarged by the formation of the recess 161. Can.

  The shape of the bottom spacer may be a shape other than the shape of the bottom spacers 40, 140, and 160 shown in FIGS. 10 to 12, for example, smaller and similar to the end face portion 20b of the electrode body 20. It may be oval.

  Furthermore, the bottom spacer may be arranged close to one short side wall 11 d side of the case main body 11 so that only one of the pair of curved portions 20 d of the electrode body 20 is opened.

Second Embodiment
FIG. 13 is an exploded perspective view showing a battery 201 according to a second embodiment of the present invention.

  As shown in FIG. 13, the battery 201 includes an insulating sheet 30 that covers the electrode body 20. The structure of the battery of this embodiment is the same as that of the first embodiment except that the insulating sheet 30 is provided.

  As shown in FIGS. 13 and 14, the insulating sheet 30 is formed in a box shape so as to be disposed along the inner surface of the case main body 11. The insulating sheet 30 is opposed to the bottom 31 facing the bottom wall 11 b of the case body 11, a pair of long side portions 32 facing the long side wall 11 c of the case 11, and the short side wall 11 d of the case 11. And a pair of short side surface portions 33b.

  At both end portions in the longitudinal direction of the bottom surface portion 31, rising portions 34 which rise substantially at right angles from the bottom surface portion 31 are provided. Openings 35 are respectively formed at four corner portions where the bottom surface portion 31, the long side surface portion 32 and the short side surface portion 33 intersect, whereby gas generated between the sheets 21, 22 and 23 of the electrode assembly 20 is generated. Can be discharged from the opening 35 to the outside of the insulating sheet 30.

  The bottom portion 31 of the insulation sheet 30 is provided with a hole 36 for gas passage. For example, a plurality of gas passage holes 36 are provided at both ends of the bottom surface portion 31 in the longitudinal direction. Thereby, the gas generated between the sheets 21, 22, 23 of the electrode assembly 20 can be discharged to the outside of the insulating sheet 30 through the holes 36 for gas passage.

  The electrode body 20 is accommodated in the case body 11 in a state of being covered by the insulating sheet 30. Thus, the insulating sheet 30 is interposed between the electrode body 20 and the inner surface of the case main body 11. Further, the bottom surface portion 31 of the insulating sheet 30 is disposed between the end surface portion 20 b of the electrode body 20 and the bottom spacer 40.

  As shown in FIG. 15, in the case main body 11, the electrode body 20 and the bottom spacer 40 are arranged in the same manner as the battery of the first embodiment (see FIG. 10). That is, the bottom spacer 40 is disposed so as to cover the pair of linear portions 20c of the electrode body 20 from the bottom side and to release the pair of curved portions 20d.

  In the second embodiment, the end face portion 20b of the electrode body 20 is covered by the bottom surface portion 31 of the insulating sheet 30, but in the portion of the bottom surface portion 31 facing the curved portion 20d, a hole 36 for gas passage is provided. It is arranged. Thereby, the gas generated between the sheets 21, 22 and 23 of the electrode assembly 40 can be discharged to the outside of the insulating sheet 30 through the curved portion 20d in the end face 20b and the hole 36 for gas passage of the insulating sheet 30. It has become.

  The gas discharged into the space between the bottom 31 of the insulating sheet 30 and the bottom wall 11 b of the case body 11 through the hole 36 for gas passage is the gas between the insulating sheet 30 and the corner 11 e of the case body 11. The space S2 can be led to the space S3 between the insulating sheet 30 and the outer peripheral surface 20e of the curved portion 20d of the electrode body 20 through the opening 35 provided at the corner of the bottom of the insulating sheet 30. These spaces S2 and S3 are formed to extend from the bottom side to the opening side along the corner portion 11e of the case main body 11, and between the lid 12 and the end face portion 20a of the electrode body 20 opposed thereto. It communicates with the safety valve 13 provided on the lid 12 through a space.

  As described above, in the second embodiment, the bottom spacer 40 and the insulating sheet 30 are provided such that the curved portion 20 d is opened at the bottom end surface 20 b of the electrode body 20. Therefore, also in the second embodiment, the safety valve 13 is communicated between the end face 20b and the bottom wall 11b of the case main body 11, more specifically, between the insulating sheet 30 and the bottom wall 11b. A communicating portion 19 is formed. Thus, the gas generated between the sheets 21, 22 and 23 of the electrode assembly 40 can be discharged from the end face 20 b to the communicating part 19 through the gas passage holes 36 of the insulating sheet 30. Since the gas discharged to the communication part 19 can rapidly flow to the safety valve 13 through the flow path including the spaces S2 and S3, the gas discharge from the safety valve 13 to the outside of the exterior body 10 can be promoted.

  As described above, according to the second embodiment, the vibration transmitted from the outside of the case body 11 to the electrode body 20 by the bottom spacer 40 interposed between the end face portion 20b of the electrode body 20 and the bottom wall portion 11b of the case body 11 And while it is possible to prevent a short circuit between the electrode body 20 and the case main body 11 by the insulating sheet 30 while suppressing an impact, between the end face portion 20 b of the electrode body 20 and the bottom wall portion 11 b of the case main body 11 The formation of the communication portion 19 can improve the gas discharge performance of the battery 1.

  However, in the second embodiment, the shape, size and arrangement of the insulating sheet 30, the arrangement, number, shape and size of the holes 36 for gas passage, and the shape and size of the bottom spacer 40 viewed from the bottom side The arrangement is not limited to the above configuration, and various changes can be made as long as a part of the end face 20b of the electrode body 20 is communicated with the spaces S2 and S3 through the holes 36 for gas passage. It is.

  For example, the arrangement, the number, the shape, and the size of the gas passage holes 36 are appropriately changed according to the position, the shape, and the size of the communication portion 19 viewed from the bottom side. Also, the configuration of the bottom spacer 40 can be modified in various ways, including the modification described in the first embodiment.

Third Embodiment
16 shows the insulating sheet 330 provided in the battery 301 according to the third embodiment of the present invention, and FIG. 17 is a cross-sectional view similar to FIG. 15 showing the internal structure of the battery 301 viewed from the bottom side. The structure of the battery of this embodiment is the same as that of the second embodiment except for the structure of the insulating sheet.

  As shown in FIGS. 16 and 17, the bottom portion 31 of the insulating sheet 30 is provided with a cut 336 for gas passage, instead of the hole 36 of the second embodiment. The notch 336 is formed, for example, in a U-shape. Thereby, when gas is generated between the sheets 21, 22, and 23 of the electrode body 20, the movable portion 338 surrounded by the notches 336 is pushed open to the bottom side by the gas, and the gas is discharged to the outside of the insulating sheet 30. It can be discharged.

  Therefore, also in the third embodiment, the safety valve 13 is communicated between the end face portion 20b and the bottom wall portion 11b of the case main body 11, more specifically, between the insulating sheet 30 and the bottom wall portion 11b. A communicating portion 19 is formed. Thereby, the gas generated between the sheets 21, 22 and 23 of the electrode assembly 40 can be discharged from the end face 20 b to the communication part 19 through the open portion of the movable part 338 in the insulating sheet 30. Since the gas discharged to the communication part 19 can rapidly flow to the safety valve 13 through the flow path including the spaces S2 and S3, the gas discharge from the safety valve 13 to the outside of the exterior body 10 can be promoted. Therefore, the same effect as that of the second embodiment can be obtained.

  In the third embodiment, when the movable portion 338 is not pushed open, the entire end face portion 20b of the electrode body 20 can be covered with the insulating sheet 30 from the bottom side, so that between the electrode body 20 and the case main body 11 Short circuiting prevention effect can be enhanced.

  However, in the third embodiment, the shape, size and arrangement of the insulating sheet 30, arrangement, number, shape and size of the slits 336 for gas passage, and shape and size of the bottom spacer 40 viewed from the bottom side The arrangement is not limited to the above-described configuration, and various configurations are possible as long as the end surface 20b of the electrode body 20 is partially communicated with the spaces S2 and S3 through the open portion of the movable portion 338 of the insulating sheet 30. Changes are possible.

  For example, the arrangement, the number, the shape, and the size of the gas passage notches 336 are appropriately changed according to the position, the shape, and the size of the communication portion 19 viewed from the bottom side. Also, the configuration of the bottom spacer 40 can be modified in various ways, including the modification described in the first embodiment.

Fourth Embodiment
FIG. 18 shows an insulating sheet 430 provided in the battery according to the fourth embodiment of the present invention. The structure of the battery of this embodiment is the same as that of the second embodiment except for the structure of the insulating sheet.

  As shown in FIG. 18, the insulating sheet 430 is provided with an engagement portion 438 that engages with the bottom spacer 40. The engaging portions 438 are provided in a pair in the bottom surface portion 31 of the insulating sheet 430 at intervals in the longitudinal direction.

  The engaging portion 438 is formed of, for example, a portion surrounded by a U-shaped notch 436 formed in the bottom portion 31. The end of the bottom spacer 40 is engageable with the engaging portion 438 formed in this manner. By engaging both end portions of the bottom spacer 40 with the pair of engaging portions 438, the bottom spacer 40 is held by the insulating sheet 430 in a state of being sandwiched between the bottom portion 31 and the pair of engaging portions 438. . Thereby, the bottom spacer 40 can be positioned with respect to the insulating sheet 430.

  Generally, in a battery in which a bottom spacer is disposed at the bottom of the case body, the bottom spacer is inserted alone into the case body. In this case, in order to prevent the bottom spacer inserted in the case main body from riding on the corner portion formed to be curved at the bottom peripheral edge of the inner surface of the case main body, the bottom spacer is used for the case main body It needs to be positioned at the bottom.

  According to the fourth embodiment, when the bottom spacer 40 is accommodated in the bottom of the case main body 11, the bottom spacer 40 and the insulating sheet 430 are positioned with the bottom spacer 40 positioned on the insulating sheet 430 using the engaging portion 438. It can be inserted into the case body 11. Therefore, the bottom spacer 40 can be easily positioned with respect to the case body 11 without using a dedicated member for positioning such as double-sided tape.

  Also in the fourth embodiment, the bottom portion 31 of the insulating sheet 430 is provided with the holes 36 for gas passage similar to the second embodiment. Therefore, the same gas discharge performance as that of the second embodiment can be obtained. However, the gas passage holes 36 are disposed so as not to interfere with the engagement portion 438 at the bottom surface portion 31.

  However, in the fourth embodiment, the shape, size and arrangement of the insulating sheet 430, arrangement, shape, size and number of the engaging portions 438, arrangement, number, shape and size of the holes 36 for gas passage, and The shape, size, and arrangement of the bottom spacer 40 are not limited to the above configuration, and a part of the end face 20b of the electrode body 20 is communicated with the spaces S2 and S3 through the gas passage holes 36, Also, as long as the bottom spacer 40 can be engaged with the engagement portion 438, various modifications are possible.

  In the fourth embodiment, the gas passage notches 336 similar to the third embodiment may be provided in place of the gas passage holes 36. Also in this case, the same gas discharge performance can be obtained.

  As mentioned above, although the present invention was described with the above-mentioned embodiment, the present invention is not limited to the above-mentioned embodiment.

  For example, in the above embodiment, the case where the safety valve as the gas discharge unit is provided in the lid has been described, but the gas discharge unit is a surface other than the surface facing the end surface portion of the electrode body via a spacer such as a bottom spacer. If it is a surface, you may be provided in the arbitrary positions of an exterior body.

  In the above embodiment, the bottom spacer disposed on the bottom side of the case main body has been described, but in the present invention, the end face of the electrode body other than the face on which the gas discharge portion such as a safety valve is provided It can be applied to any spacer placed between the parts.

  Furthermore, in the above embodiment, the electricity storage device according to the present invention has been described by taking a lithium ion secondary battery as an example, but the present invention is not limited to various lithium batteries including secondary batteries other than lithium ion secondary batteries, primary batteries and capacitors. It can be applied to a storage element.

  Further, the present invention is not limited to the so-called wound type electrode body exemplified in the above-mentioned embodiment, but a plurality of positive electrode sheets, a negative electrode sheet and a separator are each a separator of a positive electrode sheet and a negative electrode sheet. The present invention can also be applied to a so-called laminated electrode assembly formed by laminating alternately so as to overlap each other.

DESCRIPTION OF SYMBOLS 1 battery 10 exterior body 11 case main body 11a opening 11b bottom wall part 11c long side wall part 11d short side wall part 11z square cylindrical part 12 lid 12a outer side 12b inner side 19 communication part 20 electrode body 20a, 20b end face 20c straight part 20d Curved portion 20e Outer peripheral surface 20f Top portion 21 Positive electrode sheet 22 Negative electrode sheet 23 Separator 24 Positive metal foil 24a Uncoated portion 24b Projection 25 Positive electrode active material layer 26 Negative metal foil 26a Uncoated portion 26b Projection 27 Negative electrode active material Layer 28 Positive current collection tab 29 Negative current collection tab 30 Insulating sheet 31 Bottom section 32 Long side section 33 Short side section 35 Opening 36 Hole for gas passage 40 Bottom spacer 50A, 50B External terminal 51A, 51B Plate-like section 52 Axis Part 52a Expanded diameter part 53 Rivet 53a Jaw part 53b Expanded diameter part 60A, 60B Current collection Body 61A, 61B Welded portion 62A, 62B Clamped portion 70A, 70B Upper packing 80A, 80B Lower packing 90 Upper spacer 140, 160 Bottom spacer 330 Insulating sheet 336 Notch for gas passage 338 Movable section 430 Insulating sheet 430
438 engagement part

Claims (6)

An electrode body having a predetermined end face portion on which a plurality of sheets are stacked and an edge portion of the plurality of sheets is disposed;
An exterior body that has an opposing surface that faces the end surface, and that accommodates the electrode body;
A gas discharge part provided in a portion different from the facing surface part in the exterior body;
And a spacer interposed between the end face and the opposite face so that a communication part communicated with the gas discharge part is formed between the end face and the opposite face .
The electrode body is formed by overlapping a positive electrode sheet and a negative electrode sheet, which are the plurality of sheets, and a separator, and the separator is closer to the facing surface than the positive electrode sheet and the negative electrode sheet at the end face. A storage element characterized in that it is disposed so as to protrude toward the end . An electrode body having a predetermined end face portion on which a plurality of sheets are stacked and an edge portion of the plurality of sheets is disposed;
An exterior body that has an opposing surface that faces the end surface, and that accommodates the electrode body;
A gas discharge part provided in a portion different from the facing surface part in the exterior body;
A spacer interposed between the end surface portion and the opposing surface portion such that a communication portion communicated with the gas discharge portion is formed between the end surface portion and the opposing surface portion;
And an insulating sheet which is interposed between the spacer and the end face portion,
Wherein the facing portion of said communicating portion in the insulating sheet, a charge reservoir element you characterized in that cut holes or for gas passage is provided. The electrical storage element according to claim 2 , wherein the insulating sheet is provided with an engaging portion that engages with the spacer. The electrode body is a wound body formed by winding a plurality of strip-like sheets so as to form a pair of curved portions,
The storage element according to any one of claims 1 to 3, wherein the communication portion is formed to face at least one of the curved portions. The electrode body has a pair of straight portions formed between the pair of curved portions,
The spacer, so as to open and the pair of curved portions so as to cover the pair of linear portions, in claim 4, characterized in that it is interposed between the opposing surface and the end face portion Storage element of description. The exterior body includes a substantially rectangular bottom wall portion and a rectangular tubular portion rising from the periphery of the bottom wall portion,
The electrode body is accommodated in the exterior body in a posture in which a winding axis is disposed along a direction in which the rectangular cylindrical portion extends.
The spacer, the electric storage device according to claim 4 or claim 5, characterized in that it is interposed between the end face portion and the bottom wall portion.

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