JP2017126471A - Power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage element which suppresses by a separator adhesion of foreign matters to an electrode plate without accompanying thermal welding between separators.SOLUTION: A power storage element 100 includes an electrode body 20 in which a positive electrode plate 21, a negative electrode plate 22, and a separators 23, 24 are stacked. The first separator 23 has an edge portion 23a protruding from an edge 21c of the positive electrode plate 21. The edge portion 23a has a recessed end 23ad. A groove 23ae which is opened toward the protruding direction of the edge portion 23a is formed in the recessed end portion 23ad.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power storage device including an electrode body.

  Some power storage elements such as lithium secondary batteries include an electrode body in which a positive electrode plate, a negative electrode plate, and a sheet-like separator inserted between the positive electrode plate and the negative electrode plate are stacked. For example, in a wound electrode group as an electrode body of a lithium secondary battery described in Patent Document 1, a positive electrode sheet as a positive electrode plate in which a positive electrode active material mixture layer is formed on both surfaces of a positive electrode metal foil, and a negative electrode A negative electrode sheet as a negative electrode plate having a negative electrode active material mixture layer formed on both surfaces of the metal foil and two separators are stacked and wound together. Furthermore, the positive electrode metal foil of the positive electrode sheet is provided with a positive electrode lead on which the positive electrode active material layer is not formed along one side edge in the winding axis direction of the wound electrode group. Is provided with a negative electrode lead along which the negative electrode active material layer is not formed along the side edge opposite to the positive electrode lead. A positive electrode current collector is connected to the positive electrode lead, and a negative electrode current collector is connected to the negative electrode lead.

  In Patent Document 1, metal powder or metal particles of the positive electrode metal foil and the negative electrode metal foil are generated when the positive electrode lead and the positive electrode current collector are bonded and when the negative electrode lead and the negative electrode current collector are bonded. It is described that the metal powder or metal particles may come into contact with another electrode and partially penetrate the thin film separator to cause a short circuit. For this reason, in Patent Document 1, the side edges of the two separators are bonded to each other by thermal welding so as to cover the side edges of the positive electrode sheet on the side where the positive electrode lead is not formed. Further, the side edges of the two separators are bonded to each other by thermal welding so as to cover the side edges of the negative electrode sheet on the side where the negative electrode lead is not formed.

JP2011-216399A

  In patent document 1, the side edge of a separator is heat-welded. The separator can shrink when thermally welded. When thermal contraction occurs at the side edge of the separator, the distance between the positive electrode sheet and the negative electrode sheet is not uniform, thereby causing a charge bias in the electrode group. Therefore, there is a possibility that the electrode group cannot obtain a desired performance.

  The present invention has been made to solve the above-described problems, and suppresses foreign substances such as metal powder and metal particles from adhering to the electrode plates without causing thermal welding between the separators. An object is to provide a power storage element.

  In order to achieve the above object, a power storage device according to the present invention is a power storage device including an electrode body in which a positive electrode plate, a negative electrode plate, and a separator are stacked, and the separator is at least one of a positive electrode plate and a negative electrode plate. The protrusion has a protruding portion that protrudes beyond the end of the electrode plate, and the protruding portion has a recessed end, and the recessed end is formed with a recessed portion that opens toward the protruding direction of the protruding portion. ing.

  In the above-described configuration, the recessed portion opened toward the protruding direction of the protruding portion in the recessed end portion of the protruding portion of the separator captures foreign matter from the outside, and is the end portion of the electrode plate positioned opposite to the recessed portion. Prevents foreign matter from adhering to the surface. Furthermore, the recess effectively suppresses the captured foreign matter from moving onto the end of the electrode plate. The end portion with the dent is only required to be formed with the dent portion on the protruding portion of the separator, and does not require thermal welding between the separators.

  The end with a recess may have a tip that faces in a direction different from the direction opposite to the protruding direction. In the above-described configuration, the foreign matter on the recessed end portion of the separator is prevented from sliding on the recessed end portion toward the distal end portion and moving onto the end portion of the electrode plate. In addition, foreign matter near the tip on the end with a recess is likely to be caught in the recess by sliding on the end with the recess.

  The recessed end portion includes at least one first folded portion folded back in the direction opposite to the protruding direction and at least one second folded portion folded back in the protruding direction. The part may be located in the second folded part. In the above-described configuration, since the end portion with the depression is formed only by forming the first folded portion and the second folded portion on the protruding portion of the separator, the formation of the recessed end portion is facilitated. Further, by forming the first folded portion and the second folded portion into a shape extending along the end portion of the electrode plate, a recess portion extending along the end portion of the electrode plate can be formed. . Therefore, the hollow portion effectively suppresses the adhesion of foreign matter from the outside to the end portion of the electrode plate.

  The separators that are adjacent to the electrode plate on both sides may each have a protrusion including a recessed end that faces each other with the electrode plate interposed therebetween. In the above-described configuration, when the end with a recess covers the end of the electrode plate only by the end with the recess of one separator of the separators adjacent to the electrode plate on both sides, the length of the end with the recess And the rigidity of the recessed end is lowered. Therefore, the indented end portion is easily deformed to widen the gap with the separator on the opposite side across the electrode plate, so that foreign matter adheres to the end of the electrode plate through this gap. It becomes easy. On the other hand, by configuring the separators on both sides of the electrode plate so as to cover the end parts of the electrode plate facing each other, the rigidity of the end parts with the recesses of each separator is increased. Therefore, it is possible to suppress the gap between the recessed end portions of the separators on both sides from expanding.

  One of the separators adjacent to the electrode plate on both sides has a protrusion including a recessed end, and the other separator includes an end overlapping the recessed end of the one separator and You may have a protrusion part which protrudes rather than the edge part of a board. In the above-described configuration, the end portion of the electrode plate is covered with the protruding portions of the two separators that are positioned adjacent to each other on both sides of the electrode plate and are overlapped. Therefore, the effect of suppressing the adhesion of foreign matter from the outside to the end of the electrode plate is improved.

  The tip of the end of the other separator may overlap the tip of the end with a recess of the one separator. In the configuration described above, the amount of overlap between the two separators can be kept low, so that the amount of separator used can be reduced, that is, the cost can be reduced. Furthermore, since it is the structure which overlaps the front-end | tip parts of two separators, the operation | work which overlaps two separators also becomes easy.

  The electrode plate may be a positive electrode plate, the negative electrode plate may have a negative electrode protruding portion that protrudes more than the positive electrode plate in the protruding direction, and the negative electrode protruding portion may be connected to an electrode terminal of the storage element. In the above-described configuration, metal powder or metal particles that can be generated from the negative electrode protrusion when the negative electrode protrusion and the electrode terminal are connected change to metal ions when attached to the positive electrode plate. If this metal ion passes through the separator and migrates to the negative electrode plate, it may be deposited on the negative electrode plate. The deposited metal may cause a short circuit between the negative electrode plate and the positive electrode plate. By positioning the recessed end portion of the separator so as to protrude from the end portion of the positive electrode plate, it is possible to prevent the metal powder or metal particles from the negative electrode protrusion portion from adhering to the positive electrode plate.

  According to the electricity storage device of the present invention, it is possible to suppress foreign matter from adhering to the electrode plate without causing thermal welding between the separators.

It is a perspective view which shows typically the external appearance of the electrical storage element which concerns on embodiment of this invention. FIG. 2 is a perspective view in which a lid body is separated from a container body in the electricity storage device of FIG. 1. FIG. 3 is a perspective view in which a part of the electrode body of FIG. 2 is developed. FIG. 4 is an enlarged cross-sectional view of the vicinity of the end of the electrode body of FIG. 3, and is a view of a cross-section in a direction substantially perpendicular to the flat direction of the electrode body viewed from the direction IV. It is sectional drawing which shows the structure of the modification 1 of the electrical storage element which concerns on embodiment of this invention similarly to FIG. It is sectional drawing which shows the structure of the modification 2 of the electrical storage element which concerns on embodiment of this invention similarly to FIG. It is sectional drawing which shows the structure of the modification 3 of the electrical storage element which concerns on embodiment of this invention similarly to FIG. It is sectional drawing which shows the structure of the modification 4 of the electrical storage element which concerns on embodiment of this invention similarly to FIG. FIG. 10 is a cross-sectional view illustrating another aspect of the configuration of Modification 4 of the electricity storage device in FIG. 8 in the same manner as in FIG. 8. It is sectional drawing which shows the structure of the modification 5 of the electrical storage element which concerns on embodiment of this invention similarly to FIG. FIG. 11 is a cross-sectional view showing another aspect of the configuration of Modification 5 of the electricity storage device in FIG. 10 in the same manner as in FIG. 10. It is sectional drawing which shows the structure of the modification 6 of the electrical storage element which concerns on embodiment of this invention similarly to FIG. It is a top view of an electrical storage apparatus provided with the some electrical storage element which concerns on embodiment of this invention.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

  Each figure in the accompanying drawings is a schematic diagram and is not necessarily illustrated strictly. Furthermore, in each figure, the same code | symbol is attached | subjected about the same or similar component. In the following description of the embodiments, expressions with “substantially” such as substantially parallel and substantially orthogonal may be used. For example, “substantially parallel” not only means completely parallel, but also means substantially parallel, that is, including a difference of, for example, several percent. The same applies to expressions involving other “abbreviations”.

[Embodiment]
The structure of the electrical storage element 100 which concerns on embodiment is demonstrated. FIG. 1 is a perspective view schematically showing an external appearance of a power storage device 100 according to the embodiment. As shown in FIG. 1, the power storage element 100 has a flat rectangular parallelepiped outer shape. The storage element 100 is a chargeable / dischargeable secondary battery. For example, the storage element 100 is specifically a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery (also referred to as a lithium secondary battery). However, the storage element 100 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery or a capacitor.

  Referring to FIG. 1 and FIG. 2 together, the storage element 100 includes a flat rectangular parallelepiped container 10, an electrode body 20 included in the container 10, and a positive electrode terminal 30 and a negative electrode terminal 40 as electrode terminals. I have. The container 10 has a bottomed rectangular tube-shaped container main body 11 and an elongated rectangular plate-like lid body 12 that can close the opening 11a of the container main body 11. 2 is a perspective view in which the lid 12 is separated from the container main body 11 in the electricity storage device 100 of FIG. The container body 11 has a flat rectangular parallelepiped outer shape. The opening 11 a has an elongated rectangular shape like the lid 12. On the outer surface 12 a of the lid body 12, the positive terminal 30 and the negative terminal 40 are disposed. An electrolyte such as an electrolytic solution (in this embodiment, a nonaqueous electrolytic solution) is enclosed inside the container 10 together with the electrode body 20, but the liquid is not shown. As the electrolyte sealed in the container 10, there is no particular limitation on the type thereof as long as it does not impair the performance of the electricity storage device 100, and various types can be selected.

  The container body 11 and the lid body 12 are fixed with their joints in an airtight state by a joining method such as welding. Thereby, the container 10 forms the space sealed inside. The container body 11 and the lid body 12 can be made of a material that is not deformed and does not impair the airtightness of the joint when the internal pressure of the container 10 increases. Although it does not limit, the container main body 11 and the cover body 12 can be produced from weldable metals, such as stainless steel, aluminum, aluminum alloy, for example.

  The positive electrode terminal 30 and the negative electrode terminal 40 are respectively connected to the positive electrode current collector 50 and the negative electrode current collector 60 having conductivity on the side opposite to the outer surface 12 a of the lid body 12. The positive electrode current collector 50 and the negative electrode current collector 60 are further connected to the electrode body 20. Therefore, the electrode body 20 is provided so as to be suspended from the lid body 12 via the positive electrode current collector 50 and the negative electrode current collector 60. The electrode body 20 is housed in the container body 11 together with the positive electrode current collector 50 and the negative electrode current collector 60. In addition, in order to electrically insulate between the electrode body 20 and the container main body 11, the electrode body 20 may be covered with an insulating film etc. A buffer material such as a spacer may be provided between the electrode body 20 and the container body 11.

  The configuration of the electrode body 20 will be described with reference to FIGS. 2 and 3 together. 3 is a perspective view in which a part of the electrode body 20 of FIG. 2 is developed. The electrode body 20 is a power generation element capable of storing electricity. The electrode body 20 includes a sheet-like positive electrode plate 21 having a long rectangular belt-like planar shape, a sheet-like negative electrode plate 22 having a long rectangular belt-like planar shape, and a long rectangular belt-like planar shape. The sheet-like separators 23 and 24 are included so as to be layered.

  The electrode body 20 is wound in a spiral manner in the winding direction B around the winding axis A together with the positive electrode plate 21, the negative electrode plate 22, and the separators 23 and 24 stacked in layers. Is formed by. The winding axis A is a virtual axis indicated by a one-dot chain line in FIG. 3, and the electrode body 20 has a substantially symmetric configuration with respect to the winding axis A. Moreover, in this Embodiment, what started winding the positive electrode plate 21, the negative electrode plate 22, and the separators 23 and 24 is rotated in the winding direction B centering on the winding axis A, and thereby unwound belt-shaped It is assumed that the positive electrode plate 21, the negative electrode plate 22, and the separators 23 and 24 are wound. That is, the winding direction B indicated by the clockwise direction in FIG. 3 is the rotation direction of the electrode body 20 during winding. Although not limited, in the present embodiment, the electrode body 20 has a flat outer shape having an oblong shape with a flat cross section perpendicular to the winding axis A. However, the cross-sectional shape of the electrode body 20 may be other than an oval shape, and may be a circle, an ellipse, a rectangle, or other polygons.

  The positive electrode plate 21 includes a positive electrode base material 21a which is a long rectangular strip-shaped metal foil made of a metal such as aluminum or an aluminum alloy, and a coating or the like substantially over the wide main surface on both sides of the positive electrode base material 21a. And a positive electrode active material layer 21b (indicated by hatching in FIG. 3) stacked by the method. The negative electrode plate 22 includes a negative electrode base material 22a which is a long rectangular belt-shaped metal foil made of a metal such as copper or a copper alloy, and a coating or the like substantially over the wide main surface on both sides of the negative electrode base material 22a. And a negative electrode active material layer 22b (indicated by hatching in FIG. 3) stacked by the method. The separators 23 and 24 are microporous sheets made of an electrically insulating material such as a resin. In the present embodiment, the positive electrode active material layer 21b and the negative electrode active material layer 22b are formed on the main surfaces on both sides of the positive electrode substrate 21a and the negative electrode substrate 22a, respectively, but only on one main surface. May be formed.

  As a positive electrode active material used for the positive electrode active material layer 21b or a negative electrode active material used for the negative electrode active material layer 22b, a known material is appropriately used as long as it is a positive electrode active material or a negative electrode active material capable of occluding and releasing lithium ions. it can.

  In the band-like region in the vicinity of one edge 21d of the two edges 21c and 21d along the longitudinal direction of the positive electrode plate 21, the positive electrode active material layer 21b is laminated on any main surface of the positive electrode substrate 21a. Absent. The edge of the positive electrode plate 21 that forms the band-like region is referred to as a positive electrode uncoated portion 21e. The positive electrode uncoated portion 21 e is formed by the exposed positive electrode base material 21 a and forms a current collecting region of the positive electrode plate 21. Here, the edge 21c is an example of an end portion of the electrode plate.

  Further, in the band-like region in the vicinity of one edge 22c of the two edges 22c and 22d along the longitudinal direction of the negative electrode plate 22, the negative electrode active material layer 22b is laminated on any main surface of the negative electrode substrate 22a. It has not been. The edge part of the negative electrode plate 22 forming the band-like region is referred to as a negative electrode uncoated part 22e. The negative electrode uncoated portion 22 e is formed by the exposed negative electrode base material 22 a and forms a current collecting region of the negative electrode plate 22. Here, the negative electrode uncoated portion 22e is an example of a negative electrode protrusion.

  Since the positive electrode plate 21 and the negative electrode plate 22 are wound, the edge 21c and the edge 22c are located on the same side with respect to the longitudinal direction, and the edge 21d and the edge 22d are on the same side with respect to the longitudinal direction. It is piled up so that it may be located in. At this time, the positive electrode uncoated portion 21e and the negative electrode uncoated portion 22e are located on opposite sides of the overlapping portion of the positive electrode plate 21 and the negative electrode plate 22. The edge 21d of the positive electrode uncoated portion 21e protrudes from the edge 22d of the negative electrode plate 22, and the edge 22c of the negative electrode uncoated portion 22e protrudes from the edge 21c of the positive electrode plate 21.

  Two separators 23 and 24 are provided on flat main surfaces on both sides of one negative electrode plate 22, respectively. At this time, the entire negative electrode plate 22 excluding the negative electrode uncoated portion 22 e is covered with the separators 23 and 24. Then, the negative electrode uncoated portion 22 e protrudes from the separators 23 and 24 through between the separators 23 and 24. Furthermore, one positive electrode plate 21 is provided on the separator 23 so as to be positioned further inside the separator 23 adjacent to the negative electrode plate 22 on the inner side during winding. At this time, the entire positive electrode plate 21 excluding the positive electrode uncoated portion 21 e is covered with the negative electrode plate 22 and the separators 23 and 24 and faces the negative electrode plate 22. The positive electrode uncoated portion 21 e protrudes from the separators 23 and 24.

  In a state where one positive electrode plate 21, one negative electrode plate 22, and two separators 23 and 24 stacked as described above are overlapped, the coil is wound in a spiral shape in the winding direction B around the winding axis A. Thus, the electrode body 20 is formed. In the wound electrode body 20, the edges of the laminated negative electrode uncoated portions 22 e are arranged in a planar shape to form an end portion 20 a of the electrode body 20. Further, the edges of the stacked positive electrode uncoated portions 21 e are arranged in a planar shape to form the end portion 20 b of the electrode body 20.

  The configuration of the positive electrode plate 21, the negative electrode plate 22, and the separators 23 and 24 in the vicinity of the ends 20a and 20b of the electrode body 20 will be described with reference to FIGS. 4 is an enlarged cross-sectional view of the vicinity of the end portions 20a and 20b of the electrode body 20 of FIG. 3, and passes through the winding axis A of the electrode body 20 and in a direction substantially perpendicular to the flat direction of the electrode body 20. It is the figure which looked at the cross section from the direction IV.

  In the end portion 20b of the electrode body 20, in the negative electrode plate 22, the edge 22ab of the negative electrode base material 22a and the two edges 22bb of the negative electrode active material layer 22b on both sides of the negative electrode base material 22a are in the stacking direction. The edges 22d of the negative electrode plate 22 are formed so as to be substantially flush with each other in a direction substantially perpendicular to the direction from the portion 20b to the end portion 20a. Note that each of the edge 22ab and the edge 22bb is an edge along the edge 22d. In the positive electrode plate 21, the edge 21 ab of the positive electrode base material 21 a forms the edge 21 d of the positive electrode plate 21. The two edges 21bb of the positive electrode active material layer 21b on both sides of the positive electrode base material 21a are substantially flush with each other in the stacking direction, and in a direction from the end 20b toward the end 20a, than the edge 22d of the negative electrode plate 22. In the retracted position. The edge 21ab and the edge 21bb are edges along the edge 21d. The separators 23 and 24 protrude from the edge 22d of the negative electrode plate 22 in the direction from the end 20a to the end 20b. The positive electrode uncoated portion 21e including the edge 21ab of the positive electrode base material 21a protrudes from the separators 23 and 24 in the direction from the end 20a to the end 20b.

  In the end portion 20a of the electrode body 20, in the positive electrode plate 21, the edge 21aa of the positive electrode base material 21a and the two edges 21ba of the positive electrode active material layers 21b on both sides of the positive electrode base material 21a are substantially in the stacking direction. The edges 21c of the positive electrode plate 21 are formed side by side. Note that each of the edge 21aa and the edge 21ba is an edge along the edge 21c. In the negative electrode plate 22, the edge 22 aa of the negative electrode substrate 22 a forms the edge 22 c of the negative electrode plate 22. The two edges 22ba of the negative electrode active material layer 22b on both sides of the negative electrode base material 22a are substantially flush with each other in the stacking direction, and in a direction from the end 20b toward the end 20a, than the edge 21c of the positive electrode plate 21. In the protruding position. Note that each of the edge 22aa and the edge 22ba is an edge along the edge 22c. The separators 23 and 24 protrude from the edge 22ba of the negative electrode active material layer 22b in the direction from the end 20b to the end 20a. The negative electrode uncoated portion 22e including the edge 22aa of the negative electrode base material 22a protrudes from the separators 23 and 24 in the direction from the end 20b toward the end 20a.

  In the end portion 20a, the separator 23, that is, the first separator 23 has a strip-shaped edge portion 23a protruding from the positive electrode active material layer 21b adjacent to the first separator 23 in the direction from the end portion 20b to the end portion 20a. doing. That is, the edge portion 23a protrudes from the center between the end 20b and the end 20a in the electrode body 20 toward the end 20a. The edge portion 23a extends along the longitudinal direction of the first separator 23 and protrudes along the negative electrode active material layer 22b adjacent to the edge portion 23a. The edge portion 23a includes even-numbered folded portions extending along a direction intersecting with the projecting direction from the positive electrode active material layer 21b, for example, in the present embodiment, a direction intersecting substantially perpendicularly with the projecting direction. Specifically, the edge portion 23a includes two first folded portions 23aa and a second folded portion 23ab. The first folded portion 23aa and the second folded portion 23ab are arranged in this order from the edge 21ba of the positive electrode active material layer 21b toward the edge 23ac that is the tip of the edge portion 23a. Here, the edge part 23a is an example of the protrusion part of a separator, and the edge end 23ac is an example of the front-end | tip part of an edge part with a dent.

  The first folded portion 23aa has an edge portion 23a protruding from the edge 21ba of the positive electrode active material layer 21b along the negative electrode active material layer 22b, on the way to the positive electrode plate 21 side adjacent to the edge portion 23a, and the positive electrode plate. 21 is a fold portion that folds back toward the edge 21c of 21. The first folded portion 23aa is positioned adjacent to the negative electrode active material layer 22b or in the vicinity of the edge 22ba of the negative electrode active material layer 22b, and extends in the extending direction of the edge portion 23a and the edge 21c of the positive electrode plate 21. Extend along the direction. In other words, the first folded portion 23aa has an edge portion 23a in the middle of the edge portion 23a toward the opposite direction to the protruding direction of the edge portion 23a from the edge 21c of the positive electrode plate 21, and with the positive electrode plate 21 interposed therebetween. This is a fold portion that folds toward the separator 24 adjacent to the first separator 23 including 23 a, that is, toward the second separator 24.

  The second folded portion 23ab extends from the first folded portion 23aa extending toward the edge 21c of the positive electrode plate 21 to the edge portion 23a in the middle toward the second separator 24 and the positive electrode plate 21. This is a fold portion that folds in a direction away from the edge 21c. In other words, the second folded portion 23ab is a fold portion that folds the edge portion 23a halfway along the edge portion 23a from the edge 21c of the positive electrode plate 21 toward the second separator 24. Therefore, the second folded portion 23ab and the first folded portion 23aa fold the edge portion 23a in opposite directions. The second folded portion 23ab also extends along the extending direction of the edge portion 23a and the extending direction of the edge 21c of the positive electrode plate 21.

  In the edge part 23a as described above, the extending direction of the edge part 23a and the positive electrode plate are determined depending on the part from the first folded part 23aa to the second folded part 23ab and the part from the second folded part 23ab to the edge 23ac. An indented end 23ad extending along the extending direction of the edge 21c of the 21 is formed. The recessed end portion 23ad forms a groove 23ae extending continuously along the extending direction of the edge portion 23a and the extending direction of the edge 21c of the positive electrode plate 21 on the inner side. The groove 23ae has a cross section that is concave toward the edge 21c of the positive electrode plate 21 at a position facing the groove 23ae. That is, the groove 23 ae has a cross-sectional shape that opens toward the protruding direction of the edge portion 23 a from the edge 21 c of the positive electrode plate 21. Here, the groove 23ae is an example of a recess of the separator.

  In the recessed end portion 23ad having the above-described configuration, the elastic restoring force of the first separator 23 acts so as to widen the depression angle, that is, the folding angle of the first separator 23 in the two folding portions 23aa and 23ab. Thereby, the end part 23ad with a dent extends so as to cover the edge 21c of the positive electrode plate 21 adjacent to the first separator 23 including the end part 23ad with a dent. The edge 23ac of the recessed end 23ad reaches the vicinity of the second separator 24 adjacent to the first separator 23 with the positive electrode plate 21 interposed therebetween. The edge 23ac is preferably in contact with the second separator 24 as in the present embodiment, but may have a gap between the edge 23ac and the second separator 24.

  In the region from the second folded portion 23ab to the edge end 23ac in the recessed end portion 23ad, the edge end 23ac is opposed to the recessed end portion 23ab rather than the second folded portion 23ab as in the present embodiment. It is preferable to be at a position away from the edge 21c of the plate 21. That is, it is preferable that the part from the second folded portion 23ab to the edge 23ac is inclined with respect to the edge 21c of the positive electrode plate 21 so that the edge 23ac is separated from the edge 21c of the positive electrode plate 21. However, the portion from the second folded portion 23ab to the edge 23ac may extend substantially parallel to the edge 21c of the positive electrode plate 21. That is, the edge 23ac may be directed in a direction different from the direction opposite to the protruding direction of the edge portion 23a from the edge 21c of the positive electrode plate 21.

  The formation of the two folded portions 23aa and 23ab in the edge portion 23a of the first separator 23 may be performed in advance on the first separator 23 before being used for winding the electrode body 20. For example, the two folded portions 23aa and 23ab may be formed when the first separator 23 is manufactured. Alternatively, when the electrode body 20 is wound using a winding machine, a process for forming the two folded portions 23aa and 23ab is performed on the belt-shaped first separator 23 fed from the roll by the first separator 23. May be performed in parallel.

  Referring to FIGS. 2 and 3 together, at the end 20a of the electrode body 20 as described above, the negative electrode uncoated portion 22e having a plurality of layers in the flat portion of the electrode body 20 is flat. Divided into two in a direction substantially perpendicular to the direction. Furthermore, the negative electrode uncoated portions 22e divided into two are respectively converged to form a converging portion. The two converging parts are connected to the negative electrode current collector 60. The negative electrode current collector 60 has two leg portions 60a integrally. When the negative electrode current collector 60 is connected to the negative electrode terminal 40, the two leg portions 60 a extend so as to protrude from the lid body 12. The two negative electrode uncoated portions 22e of the two converging portions are respectively joined to one of the two leg portions 60a by welding such as ultrasonic welding or resistance welding.

  Further, at the end 20 b of the electrode body 20, in the flat portion of the electrode body 20, a plurality of positive electrode uncoated portions 21 e are divided into two in a direction substantially perpendicular to the flat direction of the electrode body 20. Furthermore, the positive electrode uncoated part 21e divided into two parts is converged to form a converging part. The positive electrode uncoated portions 21e of the two converging portions are respectively joined to one of the two leg portions 50a that the positive electrode current collector 50 has integrally by welding such as ultrasonic welding and resistance welding. The two leg portions 50 a also extend so as to protrude from the lid body 12 when the positive electrode current collector 50 is connected to the positive electrode terminal 30. The electrode body 20 as described above is arranged in a direction in which the outer peripheral portion formed along the winding direction is opposed to the lid body 12. The electrode body 20 having such an arrangement is called a vertically wound electrode body.

  Referring to FIG. 4, at the end 20 a of the electrode body 20, when the negative electrode uncoated portion 22 e is welded, metal powder or metal particles such as copper and copper alloy constituting the negative electrode base material 22 a are generated. There is. When the generated metal powder and metal particles are scattered toward the edge 21 c of the positive electrode plate 21, they are captured in the groove 23 ae of the edge portion 23 a of the first separator 23. In the groove 23ae recessed toward the edge 21c of the positive electrode plate 21, the metal powder and the metal particles are held while being captured, and scattering on the edge 21c of the positive electrode plate 21 is suppressed. Further, since the portion from the second folded portion 23ab to the edge end 23ac in the edge portion 23a is not inclined toward the edge 21c of the positive electrode plate 21 at a position facing the groove 23ae, the metal powder in the groove 23ae and The metal particles are suppressed from moving toward the edge 21 c of the positive electrode plate 21. Therefore, the adhesion of the metal powder and the metal particles to the edge 21c of the positive electrode plate 21 is suppressed.

  For example, when metal powder or metal particles such as copper or copper alloy constituting the negative electrode base material 22a adheres to the positive electrode base material 21a or the positive electrode active material layer 21b of the positive electrode plate 21 having a noble potential, the metal powder and metal The particles are ionized and dissolved. The metal ions can reach the negative electrode plate 22 through the separator 23 or 24 adjacent to the positive electrode active material layer 21b. The reached metal ions can be deposited as a metal on the negative electrode base material 22a or the negative electrode active material layer 22b of the negative electrode plate 22, and the deposited metal grows and is separated from the separator 23 or 24 adjacent to the negative electrode active material layer 22b. May be broken to reach the positive electrode base material 21a or the positive electrode active material layer 21b. Thereby, the negative electrode plate 22 and the positive electrode plate 21 are short-circuited. The edge portion 23a of the first separator 23 suppresses the occurrence of the short circuit as described above.

  Moreover, when the metal powder or metal particle from the negative electrode base material 22a adheres to the negative electrode plate 22 having a base potential, dissolution of the attached metal powder and metal particles hardly occurs. For this reason, metal deposition and growth thereof using the negative electrode base material 22a on the negative electrode plate 22 as a source of generation hardly occur.

  On the other hand, at the end 20b of the electrode body 20, when metal powder or metal particles such as aluminum and aluminum alloy constituting the positive electrode base material 21a that can be generated during welding of the positive electrode uncoated part 21e adheres to the negative electrode plate 22. Difficult to cause dissolution. For this reason, metal deposition and growth thereof using the positive electrode base material 21a as a source are unlikely to occur on the negative electrode plate 22. Moreover, also when the metal powder or metal particle of the positive electrode base material 21a adheres to the positive electrode plate 21, dissolution of the attached metal powder and metal particle hardly occurs.

  As described above, power storage element 100 according to the present embodiment is a power storage element including electrode body 20 in which positive electrode plate 21, negative electrode plate 22, and separators 23 and 24 are stacked. In the electrical storage element 100, the 1st separator 23 has the edge part 23a which protrudes rather than the edge 21c of the positive electrode plate 21, and the edge part 23a has the end part 23ad with a dent. A groove 23ae that opens toward the protruding direction of the edge portion 23a is formed in the end portion 23ad with a recess.

  In the above-described configuration, the groove 23ae of the recessed end portion 23ad opened in the protruding direction of the edge portion 23a captures foreign matter from the outside, and the edge of the positive electrode plate 21 located opposite to the recessed end portion 23ad. It suppresses that a foreign material adheres to 21c. Furthermore, the groove 23ae effectively suppresses the trapped foreign matter from moving onto the edge 21c of the positive electrode plate 21. The recessed end portion 23ad is only required to be formed with the groove 23ae in the edge portion 23a of the first separator 23, and does not require thermal welding between the separators 23 and 24.

  Further, when the electrode body 20 is a winding type as in the present embodiment, when the edge portions of the separators 23 and 24 are fixed not only by heat welding but also by adhesion or the like, The separator is wrinkled due to the difference in circumferential length between the separator on the peripheral side and the separator on the outer peripheral side. The soot generated in the separator makes the interval between the positive electrode plate 21 and the negative electrode plate 22 non-uniform, and causes a bias of electric charge in the electrode body 20. In the electrode body 20 of the energy storage device 100 according to the embodiment, since the edge portions of the separators 23 and 24 are not fixed to each other, slipping occurs between the separators 23 and 24 when the electrode body 20 is wound. Occurrence of wrinkles due to a difference in circumferential length between the circumferential separator and the circumferential separator is suppressed.

  In electrode body 20 of power storage device 100 according to the present embodiment, end 23ad with a recess has an edge 23ac that faces in a direction different from the direction opposite to the protruding direction of edge portion 23a of first separator 23. In the above-described configuration, the foreign matter on the recessed end portion 23ad slides on the recessed end portion 23ad toward the edge end 23ac, and on the edge 21c of the positive electrode plate 21 located opposite to the recessed end portion 23ad. The movement is suppressed. Furthermore, the foreign matter near the edge 23ac on the recessed end 23ad is likely to be caught in the groove 23ae by sliding on the recessed end 23ad.

  In the electrode body 20 of the energy storage device 100 according to the present embodiment, the recessed end portion 23ad is folded back in the direction opposite to the protruding direction of the edge portion 23a of the first separator 23, and the first folded portion 23aa. And the second folded portion 23ab folded in the protruding direction of the edge portion 23a of the one separator 23, and the groove 23ae is located in the second folded portion 23ab. In the above-described configuration, the recessed end portion 23ad is formed only by forming the first folded portion 23aa and the second folded portion 23ab on the edge portion 23a of the first separator 23. Formation becomes easy. Furthermore, by forming the first folded portion 23aa and the second folded portion 23ab along the edge 21c of the positive electrode plate 21, a groove 23ae extending along the edge 21c of the positive electrode plate 21 is formed. Can do. Therefore, the groove 23ae effectively suppresses foreign matter from adhering to the edge 21c of the positive electrode plate 21 located facing the groove 23ae from the outside.

  In the electrode body 20 of the energy storage device 100 according to the present embodiment, the edge portion 23 a of the first separator 23 having the recessed end portion 23 ad protrudes beyond the edge 21 c of the positive electrode plate 21. Further, the negative electrode plate 22 has a negative electrode uncoated portion 22 e that protrudes from the positive electrode plate 21 in the protruding direction of the edge portion 23 a, and the negative electrode uncoated portion 22 e is connected to the negative electrode terminal 40 of the electricity storage device 100. . Note that the above connection means that the negative electrode uncoated portion 22e is connected directly to the negative electrode terminal 40, or indirectly to the negative electrode terminal 40 via a conductive member such as the negative electrode current collector 60. Connected to the network. In the above-described configuration, the negative electrode uncoated portion 22e and the negative electrode terminal 40 may be generated from the negative electrode uncoated portion 22e when the negative electrode uncoated portion 22e and the negative electrode terminal 40 are connected. When the metal powder or metal particles adhere to the positive electrode plate 21, it changes to metal ions. When the metal ions pass through the separator 23 or 24 and migrate to the negative electrode plate 22, there is a possibility that the metal ions are deposited on the negative electrode plate 22. Furthermore, the deposited metal may cause a short circuit between the negative electrode plate 22 and the positive electrode plate 21. However, in the end portion 20a of the electrode body 20 where the negative electrode uncoated portion 22e exists, the recessed end portion 23ad of the first separator 23 is positioned so as to protrude from the edge 21c of the positive electrode plate 21. It can suppress that the metal powder or metal particle from the coating part 22e adheres to the positive electrode plate 21. FIG.

[Modification 1]
Moreover, the following structures are mentioned as the modification 1 of the electrical storage element 100 which concerns on embodiment. Specifically, as shown in FIG. 5, in the electrode body of the energy storage device according to Modification 1, at the edge 20 a of the electrode body, on either edge portion of the first separator 23 and the second separator 24, Even-numbered folded portions, specifically, two folded portions are formed. FIG. 5 is a cross-sectional view showing the configuration of Modification Example 1 of power storage element 100 according to the embodiment in the same manner as FIG. Further, in the following description of the modified examples, the constituent elements having the same reference numerals as the reference numerals in the previous drawings are the same or similar constituent elements, and thus detailed description thereof is omitted.

  Referring to FIG. 5, at the end portion 20a of the electrode body, the first separator 23 has an edge portion 23a including a recessed end portion 23ad that forms a groove 23ae, as in the case of the power storage device 100 according to the embodiment. Have. The edge portion 23a includes a first folded portion 23aa, a second folded portion 23ab, and an edge 23ac. In the first modification, the edge 23ac reaches the vicinity of the middle between the first separator 23 and the second separator 24.

  Further, at the end portion 20 a, the second separator 24 is a belt-like shape protruding in a direction from the end portion 20 b of the electrode body toward the end portion 20 a rather than the positive electrode active material layer 21 b of the positive electrode plate 21 adjacent to the second separator 24. It has the edge part 24a which is a protrusion part. The edge portion 24a extends along the longitudinal direction of the second separator 24 and protrudes along the negative electrode active material layer 22b of the negative electrode plate 22 adjacent to the edge portion 24a. Similarly to the edge portion 23a of the first separator 23, the edge portion 24a includes a first turn-up portion 24aa and a second turn-up portion 24ab in order toward the edge end 24ac that is the tip thereof.

  The first folded portion 24aa is a fold portion that folds the edge portion 24a in the middle thereof toward the positive electrode plate 21 adjacent to the edge portion 24a and toward the edge 21c of the positive electrode plate 21. The first folded portion 24aa is located adjacent to the negative electrode active material layer 22b or in the vicinity of the edge 22ba of the negative electrode active material layer 22b, and extends in the extending direction of the edge portion 24a and the edge 21c of the positive electrode plate 21. Extend along the direction.

  The second folded portion 24ab has an edge portion 24a extending from the first folded portion 24aa toward the edge 21c of the positive electrode plate 21 in the middle thereof toward the first separator 23 facing the positive electrode plate 21 and the above-mentioned This is a fold portion that folds back in a direction away from the edge 21 c of the positive electrode plate 21. The second folded portion 24bb extends along the extending direction of the edge portion 24a and the extending direction of the edge 21c of the positive electrode plate 21.

  The edge portion 24a as described above has a recessed end portion 24ad formed by a portion from the first folded portion 24aa to the edge end 24ac. The recessed end portion 24ad is positioned so as to face the edge 21c of the positive electrode plate 21 adjacent to the edge portion 24a. The indented end portion 24 ad forms a groove 24 ae that extends continuously along the extending direction of the edge portion 24 a and the extending direction of the edge 21 c of the positive electrode plate 21. The groove 24 ae is open toward the protruding direction of the edge portion 24 a from the edge 21 c of the positive electrode plate 21. In the first modification, the edge 24ac reaches the vicinity of the middle between the first separator 23 and the second separator 24. Further, the portion from the second folded portion 24ab to the edge 24ac in the recessed end 24ad is inclined with respect to the edge 21c of the positive electrode plate 21 so that the edge 24ac is separated from the edge 21c of the positive electrode plate 21. Is preferred. However, the part may extend substantially parallel to the edge 21 c of the positive electrode plate 21.

  The recessed end portions 23ad and 24ad having the above-described configuration are in positions facing each other in the stacking direction of the positive electrode plate 21 and the negative electrode plate 22 with the positive electrode plate 21 therebetween. The recessed end portions 23ad and 24ad extend so as to cover the edge 21c of the positive electrode plate 21 between them. The edge 23ac of the edge portion 23a and the edge 24ac of the edge portion 24a may or may not be in contact. Further, the edge portions 24a and 24b may be formed so as to have a substantially symmetrical relationship with respect to the positive electrode plate 21 therebetween.

  In addition, since the other configuration of the power storage element according to Modification Example 1 is the same as that of power storage element 100 according to the embodiment, description thereof is omitted. Furthermore, according to the electricity storage device according to the first modification, the same effect as the electricity storage device 100 according to the embodiment can be obtained. Furthermore, as described above, in the electricity storage device according to the first modification, the separators 23 and 24 adjacent to the positive electrode plate 21 on both sides respectively include the recessed end portions 23ad and 24ad facing each other with the positive electrode plate 21 interposed therebetween. It has edge portions 23a and 24a. In the above-described configuration, when the positive electrode plate 21 is configured so as to cover the edge 21c of the positive electrode plate 21 only by the end portion 23ad with the depression of the first separator 23 which is one of the separators 23 and 24 adjacent to the positive electrode plate 21 on both sides, the depression 21 The length of the attached end portion 23ad is increased, and the rigidity of the recessed end portion 23ad is decreased. Therefore, the recessed end portion 23ad is easily deformed so as to widen the gap with the second separator 24 on the opposite side, whereby foreign matter adheres to the edge 21c of the positive electrode plate 21 through this gap. It becomes easy. On the other hand, by forming the recessed portions 23ad and 24ad facing each other of the separators 23 and 24 on both sides of the positive electrode plate 21 so as to cover the edge 21c of the positive electrode plate 21, the recessed ends of the separators 23 and 24 are formed. The rigidity of the parts 23ad and 24ad is increased. Therefore, it is possible to suppress the gap between the recessed end portions 23ad and 24ad of the separators 23 and 24 on both sides from expanding.

[Modification 2]
Moreover, the following structures are mentioned as the modification 2 of the electrical storage element 100 which concerns on embodiment. Specifically, as shown in FIG. 6, in the electrode body of the energy storage device according to the second modification, the first separator 23 and the second separator 24 at the end 20 b of the electrode body including the positive electrode uncoated part 21 e. In each of the edge portions, even-numbered folded portions, specifically, two folded portions are formed. FIG. 6 is a cross-sectional view showing the configuration of Modification Example 2 of power storage element 100 according to the embodiment in the same manner as FIG.

  Referring to FIG. 6, at the end 20a of the electrode body, the edge portion of the first separator 23, that is, the first edge portion 23a, is similar to the electrode body 20 of the energy storage device 100 according to the embodiment. And a recessed end 23ad formed by 23ab.

  At the end 20b of the electrode body, the first separator 23 is a belt-like shape that protrudes in the direction from the end 20a of the electrode body toward the end 20b rather than the positive electrode active material layer 21b of the positive electrode plate 21 adjacent to the first separator 23. Second edge portion 23b. The second separator 24 has a strip-shaped second edge portion 24b that protrudes in a direction from the end 20a to the end 20b of the electrode body, rather than the positive electrode active material layer 21b of the positive electrode plate 21 adjacent to the second separator 24. .

  The second edge portion 23b has the same configuration as the edge portion 23a on the end 20a side in the first separator 23 of the electrode body of the electricity storage device according to the first modification. That is, the second edge portion 23b has a recessed end portion 23bd formed by the first folded portion 23ba and the second folded portion 23bb which are sequentially arranged toward the edge end 23bc. The recessed end portion 23bd continuously extends along the extending direction of the second edge portion 23b on the inner side thereof and opens toward the protruding direction of the second edge portion 23b from the edge 21d of the positive electrode plate 21. The groove 23be is formed. In the second modification, the edge 23 bc of the second edge portion 23 b reaches the vicinity of the positive electrode uncoated portion 21 e of the positive electrode plate 21 between the first separator 23 and the second separator 24. The edge 23bc may or may not be in contact with the positive electrode uncoated portion 21e.

  The second edge portion 24b has the same configuration as the edge portion 24a on the end 20a side of the second separator 24 of the electrode body of the electricity storage device according to the first modification. That is, the second edge portion 24b has a recessed end portion 24bd formed by the first folded portion 24ba and the second folded portion 24bb that are sequentially arranged toward the edge end 24bc. The recessed end portion 24bd continuously extends along the extending direction of the second edge portion 24b and opens toward the protruding direction of the second edge portion 24b from the edge 21d of the positive electrode plate 21. The groove 24be is formed. In the second modification, the edge 24 bc of the second edge portion 24 b reaches the vicinity of the positive electrode uncoated portion 21 e of the positive electrode plate 21 between the first separator 23 and the second separator 24. The edge 24bc may or may not be in contact with the positive electrode uncoated portion 21e.

  The recessed end portion 23bd of the second edge portion 23b and the recessed end portion 24bd of the second edge portion 24b are related to the positive electrode base material 21a therebetween, that is, the stacking direction of the positive electrode plate 21 and the negative electrode plate 22 It may be formed so as to have a substantially symmetric relationship with respect to a plane substantially perpendicular to.

  The recessed end portion 23bd of the second edge portion 23b having the above-described configuration is formed on one positive electrode active material layer 21b adjacent to the second edge portion 23b of the two positive electrode active material layers 21b of the positive electrode plate 21. It extends so as to cover the edge 21bb. The recessed edge portion 24bd of the second edge portion 24b covers the edge 21bb of the other positive electrode active material layer 21b adjacent to the second edge portion 24b of the two positive electrode active material layers 21b of the positive electrode plate 21. Extend.

  In addition, the other configuration of the power storage element according to Modification 2 is the same as that of the power storage element according to the embodiment or the above-described modification, and thus the description thereof is omitted. Furthermore, according to the electricity storage device according to Modification 2, the same effects as those of the electricity storage device according to the embodiment and the above-described modification can be obtained. Furthermore, as described above, in the electrode body of the energy storage device according to Modification 2, not only the end portion 20a side but also the end portion 20b side of the electrode body covers the edge 21d of the positive electrode plate 21 with the separators 23 and 24. Accordingly, it is possible to effectively suppress the adhesion of foreign matters to both edges 21c and 21d of the positive electrode plate 21. For example, even when metal powder or metal particles generated from the negative electrode base material 22a in the end portion 20a flows to the end portion 20b, adhesion to the edge 21bb of the positive electrode active material layer 21b is suppressed.

[Modification 3]
Moreover, the following structures are mentioned as the modification 3 of the electrical storage element 100 which concerns on embodiment. Specifically, as shown in FIG. 7, in the electrode body of the energy storage device according to Modification 3, the edge portion 23 a of the first separator 23 has four folded portions at the end 20 a of the electrode body. Yes. FIG. 7 is a cross-sectional view showing the configuration of Modification 3 of power storage device 100 according to the embodiment in the same manner as FIG.

  Referring to FIG. 7, the edge portion 23 a includes a first folded portion 23 aa, a second folded portion 23 ab, a third folded portion 23 aaa, and a fourth folded portion 23 ab arranged in order toward the edge 23ac. Yes. The folded portions 23aa, 23ab, 23aa, and 23aba extend along the extending direction of the edge portion 23a and the extending direction of the edge 21c of the positive electrode plate 21.

  Each of the first folded portion 23aa and the second folded portion 23ab has the same configuration as the first folded portion 23aa and the second folded portion 23ab of the first separator 23 in the electrode body 20 of the energy storage device 100 according to the embodiment. ing. The third folded portion 23aa is a fold that folds the edge portion 23a from the second folded portion 23ab to the edge 23ac extending in the direction away from the edge 21c of the positive electrode plate 21 toward the edge 21c of the positive electrode plate 21 in the middle thereof. It is a part of. In the third folded portion 23aaa, the edge portion 23a is folded in the same direction as the first folded portion 23aa. The fourth folded portion 23aba folds the edge portion 23a extending from the third folded portion 23aa to the edge end 23ac extending toward the edge 21c of the positive electrode plate 21 in the direction away from the edge 21c of the positive electrode plate 21. It is a part of. In the fourth folded portion 23aba, the edge portion 23a is folded in the same direction as the second folded portion 23ab. The portion from the fourth folded portion 23aba to the edge portion 23a in the edge portion 23a may extend substantially parallel to the edge 21c of the positive electrode plate 21.

  In the edge portion 23a, the folded portions 23aa, 23ab, 23aa, and 23aba form a recessed end portion 23ad. The recessed end portion 23ad is formed therein with a first groove 23ae and a second groove 23aea that extend continuously along the extending direction of the edge portion 23a and the extending direction of the edge 21c of the positive electrode plate 21. . The first groove 23ae is formed by a portion from the first folded portion 23aa to the third folded portion 23aaa through the second folded portion 23ab in the recessed end portion 23ad. The second groove 23aea is formed by a portion from the third folded portion 23aa to the edge 23ac through the fourth folded portion 23aba in the recessed end portion 23ad. The first groove 23 ae and the second groove 23 aea are open toward the protruding direction of the edge portion 23 a from the positive electrode plate 21.

  In the third modification, the edge 23ac of the edge portion 23a reaches the vicinity of the second separator 24 adjacent to the first separator 23 with the positive electrode plate 21 adjacent to the first separator 23 including the edge portion 23a interposed therebetween. The edge 23ac is preferably in contact with the second separator 24, but may have a gap with the second separator 24.

  In addition, since the other configuration of the power storage element according to Modification 3 is the same as that of power storage element 100 according to the embodiment, the description thereof is omitted. Furthermore, according to the electricity storage device according to Modification 3, the same effect as that of electricity storage device 100 according to the embodiment can be obtained. Furthermore, as described above, in the electrode body of the energy storage device according to the modification example 3, the edge portion 23a of the first separator 23 has the four folded portions 23aa, 23ab, 23aaa, and 23aba. In the above-described configuration, the folded angle of the first separator 23 at the folded portions 23aa, 23ab, 23aa, and 23aba is narrowed at the recessed end portion 23ad of the edge portion 23a. Thereby, since the space | interval of the folded-back site | parts in the 1st separator 23 becomes narrow, the foreign material caught in groove | channel 23ae and 23aea becomes easy to be hold | maintained as it is.

[Modification 4]
Moreover, the following structures are mentioned as the modification 4 of the electrical storage element 100 which concerns on embodiment. Specifically, as shown in FIG. 8, in the electrode body of the energy storage device according to the modified example 4, the edge portion of the second separator 24 at the end portion 20 a of the electrode body is an odd-numbered folded portion. Has one folded portion. FIG. 8 is a cross-sectional view showing the configuration of Modification 4 of power storage device 100 according to the embodiment in the same manner as FIG.

  Referring to FIG. 8, at the end portion 20a of the electrode body, the first separator 23 has an edge portion 23a including a recessed end portion 23ad that forms a groove 23ae, as in the case of the power storage device 100 according to the embodiment. Have.

  The second separator 24 is an edge portion 24a that is a strip-like protruding portion that protrudes in a direction from the end 20b of the electrode body toward the end 20a rather than the positive electrode active material layer 21b of the positive electrode plate 21 adjacent to the second separator 24. Have The edge portion 24a extends along the longitudinal direction of the second separator 24 and protrudes along the negative electrode active material layer 22b of the negative electrode plate 22 adjacent to the edge portion 24a.

  The edge portion 24a includes one folded portion 24aa. The folded portion 24aa is a fold portion that folds the edge portion 24a toward the positive electrode plate 21 adjacent to the edge portion 24a and toward the edge 21c of the positive electrode plate 21. The folded portion 24aa is positioned adjacent to the negative electrode active material layer 22b or in the vicinity of the edge 22ba of the negative electrode active material layer 22b, and extends in the extending direction of the edge portion 24a and the extending direction of the edge 21c of the positive electrode plate 21. Extending along.

  The tip end portion 24a1 between the edge 24ac of the edge portion 24a of the second separator 24 and the folded portion 24aa is formed by the edge 23ac and the second folded portion 23ab of the recessed end portion 23ad of the edge portion 23a of the first separator 23. It extends along the tip portion 23a1 between the two. Furthermore, the tip end portion 24a1 of the edge portion 24a is in contact with and overlaps the tip end portion 23a1 of the recessed end portion 23ad. That is, the edge portion 24a is bent into a shape having a tip end portion 24a1 that overlaps the recessed end portion 23ad. Thereby, the edge 21c of the positive electrode plate 21 is covered so as to be surrounded by the edge portion 24a and the edge portion 23a that position the tip portion 24a1 and the tip portion 23a1 so as to overlap each other.

  In the fourth modification, the distal end portion 24a1 of the edge portion 24a is located on the edge 21c side of the positive electrode plate 21 with respect to the distal end portion 23a1 of the recessed end portion 23ad. However, as shown in FIG. 9, the tip portion 24a1 of the edge portion 24a may be located on the opposite side of the edge portion 21c of the positive electrode plate 21 with respect to the tip portion 23a1 of the recessed portion 23ad. 9 is a cross-sectional view showing another aspect of the configuration of Modification 4 of the electricity storage device of FIG. 8 in the same manner as FIG. Furthermore, the whole tip part 24a1 may overlap with a part or the whole of the tip part 23a1, and a part of the tip part 24a1 may overlap with a part or the whole of the tip part 23a1. Moreover, there may be a gap between the tip portion 24a1 of the edge portion 24a and the tip portion 23a1 of the recessed end portion 23ad without contact. With the above-described configuration, the tip end portion 24a1 of the edge portion 24a and the tip end portion 23a1 of the recessed end portion 23ad cover the edge 21c of the positive electrode plate 21 without a gap. Furthermore, even when vibration, impact, or the like is applied to the electrode body 20, it is possible to prevent the distal end portion 24a1 of the edge portion 24a from being separated from the distal end portion 23a1 of the recessed end portion 23ad and opening the cover.

  In addition, since the other configuration of the power storage element according to Modification Example 4 is the same as that of power storage element 100 according to the embodiment, description thereof is omitted. Furthermore, according to the electricity storage device according to Modification Example 4, the same effect as that of electricity storage device 100 according to the embodiment can be obtained.

  Furthermore, as described above, in the electrode body of the energy storage device according to the modified example 4, the first separator 23 of the separators 23 and 24 adjacent to the positive electrode plate 21 on both sides includes an edge portion including the recessed end portion 23ad. The second separator 24 includes an end portion 24 a 1 that overlaps the recessed end portion 23 ad of the first separator 23 and has an edge portion 24 a that protrudes from the edge 21 c of the positive electrode plate 21. In the above-described configuration, the edge 21 c of the positive electrode plate 21 is covered with the edge portions 23 a and 24 a of the two separators 23 and 24 that are adjacent to and overlap each other on the positive electrode plate 21. Therefore, the effect of suppressing the adhesion of foreign matters to the edge 21c of the positive electrode plate 21 from the outside is improved.

  Further, in the electrode body of the energy storage device according to Modification 3, the tip portion 24 a 1 that is the tip portion of the second separator 24 overlaps the tip portion 23 a 1 that is the tip portion of the recessed end portion 23 ad of the first separator 23. In the above configuration, the amount of overlap between the two separators 23 and 24 can be kept low, so that the amount of separator used can be reduced, that is, the cost can be reduced. Furthermore, since the tip portions 23a1 and 24a1 of the two separators 23 and 24 are stacked, the operation of stacking the two separators 23 and 24 is facilitated.

[Modification 5]
Moreover, the following structures are mentioned as the modification 5 of the electrical storage element 100 which concerns on embodiment. Specifically, as shown in FIG. 10, in the end portion 20 a of the electrode body of the electricity storage device according to the modified example 5, the edge portion of the second separator 24 is an odd number of folded portions, specifically three It has a folded part. That is, the edge part of the 2nd separator 24 has the structure which provided the edge part with a dent in the edge part 24a of the 2nd separator 24 of the electrical storage element which concerns on the modification 4. FIG. FIG. 10 is a cross-sectional view showing the configuration of Modification 5 of power storage element 100 according to the embodiment in the same manner as FIG.

  Referring to FIG. 10, in the end portion 20a of the electrode body, the edge portion 23a of the first separator 23 includes a recessed end portion 23ad that forms a groove 23ae, as in the case of the power storage device 100 according to the embodiment. .

  The edge part 24a of the second separator 24 has a first folded part 24aa, a second folded part 24ab, and a third folded part 24aaa arranged in this order toward the edge 24ac. The folded portions 24aa, 24ab, and 24aaa extend along the extending direction of the edge portion 24a and the extending direction of the edge 21c of the positive electrode plate 21.

  Each of the first folded portion 24aa and the second folded portion 24ab has the same configuration as the first folded portion 24aa and the second folded portion 24ab of the second separator 24 in the electrode body of the electric storage element according to Modification 1. . The third folded portion 24aaa is a fold that folds the edge portion 24a extending from the second folded portion 24ab to the edge 24ac in the direction away from the edge 21c of the positive electrode plate 21 toward the edge 21c of the positive electrode plate 21 in the middle thereof. It is a part of. In the third folded portion 24aaa, the edge portion 24a is folded in the same direction as the first folded portion 24aa.

  In the edge portion 24a, a recessed end portion 24ad including the folded portions 24aa, 24ab, and 24aaa is formed. The indented end portion 24 ad forms a groove 24 ae that extends continuously along the extending direction of the edge portion 24 a and the extending direction of the edge 21 c of the positive electrode plate 21. The groove 24ae is formed by a portion from the first folded portion 24aa to the third folded portion 24aaa via the second folded portion 24ab in the recessed end portion 24ad. A portion from the third folded portion 24aaa to the edge end 24ac in the recessed end portion 24ad forms a distal end portion 24a1.

  The tip end portion 24 a 1 of the edge portion 24 a of the second separator 24 extends along the tip end portion 23 a 1 of the recessed end portion 23 ad of the first separator 23. Furthermore, the tip end portion 24a1 of the edge portion 24a is in contact with and overlaps the tip end portion 23a1 of the recessed end portion 23ad. Thereby, the edge 21c of the positive electrode plate 21 is covered so as to be surrounded by the edge portion 24a and the edge portion 23a that position the tip portion 24a1 and the tip portion 23a1 so as to overlap each other.

  In the fifth modification, the tip end portion 24a1 of the edge portion 24a is located on the edge 21c side of the positive electrode plate 21 with respect to the tip end portion 23a1 of the recessed end portion 23ad. However, as shown in FIG. 11, the tip portion 24a1 of the edge portion 24a may be located on the side opposite to the edge 21c of the positive electrode plate 21 with respect to the tip portion 23a1 of the recessed portion 23ad. 11 is a cross-sectional view showing another aspect of the configuration of Modification 5 of the electricity storage device of FIG. 10 in the same manner as FIG. Furthermore, the whole tip part 24a1 may overlap with a part or the whole of the tip part 23a1, and a part of the tip part 24a1 may overlap with a part or the whole of the tip part 23a1. Further, the tip end portion 24a1 of the edge portion 24a and the tip end portion 23a1 of the recessed end portion 23ad are not in contact with each other, and there may be a gap between them.

  Other configurations of the electricity storage device according to Modification Example 5 are the same as those of the electricity storage device according to Modification Example 4, and thus the description thereof is omitted. Furthermore, according to the electricity storage device according to Modification Example 5, the same effects as those of the electricity storage device according to Modification Example 4 can be obtained. Furthermore, as described above, in the electrode body of the energy storage device according to the modified example 5, the edge portion 23a of the first separator 23 and the edge portion 24a of the second separator 24 have the recessed end portions 23ad and 24ad, respectively. . Thereby, since the space | interval of the folded-back site | parts in the 1st separator 23 and the 2nd separator 24 becomes narrow, it becomes easy to hold | maintain the foreign material caught in groove | channel 23ae and 24ae as it is.

[Modification 6]
Moreover, the following structures are mentioned as the modification 6 of the electrical storage element 100 which concerns on embodiment. Specifically, as shown in FIG. 12, in the end portion 20a of the electrode body of the electricity storage device according to the modified example 6, the edge portion 23a of the first separator 23 is formed with a plurality of recesses at the recessed end portion. It has a configuration. FIG. 12 is a cross-sectional view showing the configuration of Modification 6 of power storage device 100 according to the embodiment in the same manner as FIG.

  Referring to FIG. 12, at the end portion 20a of the electrode body, the edge portion 23a of the first separator 23 is adjacent to the first separator 23 with the positive electrode plate 21 in between at the bent portion 23af in the middle of the edge portion 23a. The two separators 24 are bent. The bent portion 23af extends along the extending direction of the edge portion 23a and the edge 21c of the positive electrode plate 21. The edge portion 23a includes a recessed end portion 23ad between the bent portion 23af and the edge end 23ac. In the sixth modification, the edge 23ac of the recessed end 23ad is in contact with the second separator 24. However, there may be a gap between the edge 23ac and the second separator 24.

  In the recessed end portion 23ad, a plurality of recesses 23ag recessed toward the edge 21c of the positive electrode plate 21 adjacent to the edge portion 23a, that is, in the direction opposite to the protruding direction of the edge portion 23a from the edge 21c of the positive electrode plate 21. Is formed. The plurality of recesses 23ag are arranged at intervals from each other along the extending direction of the edge portion 23a. The shape and size of each recess 23ag may be the same as or different from each other. The shape of the recess 23ag may be any shape. In the sixth modification, the plurality of recesses 23ag are arranged in a line along the extending direction of the edge portion 23a. However, the plurality of recesses 23ag may be arranged in a plurality of lines and distributed without forming a line. May be.

  The recess 23ag of the recessed end 23ad may be formed when the first separator 23 is manufactured, or may be formed by processing the manufactured first separator 23. The recessed portion 23ag of the recessed end portion 23ad can be formed without thermal welding between the separators.

  The recessed end portion 23ad of the edge portion 23a having the above-described configuration extends so as to cover the edge 21c of the positive electrode plate 21. And the recessed part 23ag of the edge part 23ad with a dent can capture | acquire the foreign material from the outer side, and can hold | maintain the captured foreign material in the inside. Therefore, it is suppressed that a foreign material adheres to the edge 21c of the positive electrode plate 21 located facing the recessed end portion 23ad. In addition, since the other configuration of the power storage element according to Modification 6 is the same as that of power storage element 100 according to the embodiment, the description thereof is omitted. Furthermore, according to the electricity storage device according to Modification 6, the same effect as that of electricity storage device 100 according to the embodiment can be obtained.

[Other variations]
The power storage device according to the embodiment and the modification of the present invention has been described above, but the present invention is not limited to the embodiment and the modification. That is, it should be considered that the embodiment and the modification disclosed this time are examples in all respects and are not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  In the electrode body of the electricity storage device according to the embodiment and the modification, the recessed end portion 23ad of the edge portion 23a of the first separator 23 is formed by two or four folded portions, but the present invention is limited to this. Not a thing. The edge part with a dent of the edge part 23a may be formed by the even-folded folding | turning part, and may be formed by six or more folding | turning parts. Moreover, although the two folding | turning parts were formed also in the edge part 24a of the 2nd separator 24, it is not limited to this. The recessed end portion of the edge portion 24a may be formed by an even number of folded portions, or may be formed by four or more folded portions.

  Alternatively, in the electrode body of the energy storage device according to Modifications 4 and 5, one or three folded portions are formed in the edge portion 24a of the second separator 24 that overlaps the edge portion 23a of the first separator 23 at the tip portion. However, it is not limited to this. The edge portion 24a may be formed with odd-numbered folded portions, and may be formed with five or more folded portions.

  Furthermore, in the electrode body of the energy storage device according to Modifications 4 and 5, the tip portion 24a1 of the edge portion 24a of the second separator 24 is configured to overlap the tip portion 23a1 of the recessed end portion 23ad of the first separator 23. However, it is not limited to this. For example, when the recessed end portion 23ad of the first separator 23 includes four or more folded portions, and the edge portion 24a of the second separator 24 includes three or more folded portions, the edge portion 24a of the second separator 24 is A plurality of folded portions including the tip portion 24a1 may overlap the recessed end portion 23ad.

  In the electrode body of the energy storage device according to Modification 2, the recessed end portion 23bd of the edge portion 23b of the first separator 23 and the recessed end portion 24bd of the edge portion 24b of the second separator 24 each have two folded portions. However, the present invention is not limited to this. The recessed end portions of the edge portions 23b and 24bd may be formed by even-numbered folded portions, or may be formed by four or more folded portions.

  In the electrode body of the energy storage device according to the embodiment and the modification, the configuration of the edge portion 23a of the first separator 23 and the configuration of the edge portion 24a of the second separator 24 may be interchanged.

  In the electrode body of the energy storage device according to the embodiment and the modification, the recessed end portions of the first separator 23 and the second separator 24 cover the edge 21c of the positive electrode plate 21 at the end portion 20a, and the positive electrode plate at the end portion 20b. Although it is configured to cover the edge 21bb of the 21 positive electrode active material layer 21b, it is not limited to this. The recessed end portions of the first separator 23 and the second separator 24 are configured to cover the edge 22ba of the negative electrode active material layer 22b of the negative electrode plate 22 at the end portion 20a or the edge 22d of the negative electrode plate 22 at the end portion 20b. May be.

  In the electrode body of the energy storage device according to the embodiment and the modification, the recessed end portions of the first separator 23 and the second separator 24 are formed by folding the separator, but the present invention is not limited to this. The indented end portion may be formed by curving the separator, or may be formed by combining the curving and folding of the separator. The groove at the end with the depression may be formed by folding the separator into a U-shape or a part of a polygon instead of bending the separator into a V-shape. Moreover, the groove | channel of the edge part with a hollow and the 1st folding | turning part of a separator do not need to adjoin. For example, there may be a portion extending substantially parallel to the edge of the positive electrode plate 21 or the negative electrode plate 22 between the groove of the recessed end portion and the first folded portion of the separator.

  In the energy storage device according to the embodiment and the modification, the stacked electrode body is a wound electrode body formed by winding the stacked positive electrode plate, negative electrode plate, and separator, but is not limited thereto. It is not what is done. The stacked electrode body may be a stack type electrode body formed by stacking a large number of positive electrode plates, negative electrode plates, and separators. One set or two or more sets of stacked positive electrode plates, negative electrodes It may be a Z-shaped electrode body formed by bending a plurality of plates and separators.

  The electricity storage device according to the embodiment and the modification includes one electrode body. However, the power storage element may include two or more electrode bodies.

  In the energy storage device according to the embodiment and the modification, the electrode body has a configuration in which the strip-like positive electrode uncoated portion 21e and the negative electrode uncoated portion 22e are connected to the positive electrode current collector 50 and the negative electrode current collector 60, respectively. However, it is not limited to this. The electrode body has a tab that protrudes integrally from the positive electrode base material and the negative electrode base material and is not formed with the positive electrode active material layer and the negative electrode active material layer at the positions of the positive electrode uncoated part and the negative electrode uncoated part. It may be. The positive electrode current collector 50 and the negative electrode current collector 60 may be connected to the tab.

  The power storage element according to the embodiment and the modification is a power storage element including a vertically wound electrode body, but in an orientation in which the end of the electrode body in the winding axis A direction is opposed to the lid body 12 of the container 10. An electricity storage device including a horizontally wound electrode body on which the electrode body is disposed may be used.

  In addition, embodiments constructed by arbitrarily combining the embodiment and the modified examples are also included in the scope of the present invention. In addition, the present invention can be realized not only as a power storage element as described above but also in a power storage device including one or more power storage elements. For example, the present invention can be realized as a power storage device 200 including a plurality of power storage elements 100 as shown in FIG. FIG. 13 is a plan view of a power storage device 200 including a plurality of power storage elements 100. The power storage device 200 includes a plurality of power storage units 201 (four power storage units 201 in FIG. 13) arranged side by side. Each power storage unit 201 includes, for example, a plurality of power storage elements 100 arranged in a line and electrically connected to each other (four power storage elements 100 in FIG. 13). With the above-described configuration, the plurality of power storage elements 100 are used as one unit, and the quantity and arrangement of the power storage units 201 are selected according to the electric capacity required for the power storage device 200, the shape and dimensions of the power storage device 200, and the like. obtain. A power storage device 200 including a plurality of power storage elements 100 and having high output can be mounted as a power source for vehicles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV).

  The present invention can be applied to power storage elements such as lithium ion secondary batteries, power storage units, power storage devices, and the like.

20 Electrode body 21 Positive electrode plate 21c Edge (edge part of electrode plate)
22 Negative electrode plate 22e Negative electrode uncoated part (negative electrode protruding part)
23 1st separator 24 2nd separator 23a, 24a Edge part (protrusion part)
23b, 24b 2nd edge part (protrusion part)
23aa, 23ba, 24aa, 24ba First folded portion 23ab, 23bb, 24ab, 24bb Second folded portion 23aa, 24aaa Third folded portion 23aba Fourth folded portion 23ac, 23bc, 24ac, 24bc Part)
23ad, 23bd, 24ad, 24bd End with recess 23ae, 23be, 24ae, 24be Groove (depression)
23 aea second groove (dent)
23ag recess (dent)
40 Negative terminal (electrode terminal)
100 Power storage element

Claims (7)

A power storage device comprising an electrode body in which a positive electrode plate, a negative electrode plate and a separator are laminated,
The separator has a protruding portion that protrudes from an end portion of at least one of the positive electrode plate and the negative electrode plate, and the protruding portion has an indented end portion, and the indented end portion is Is a recess that is open toward the protruding direction of the protruding portion. The electric storage element according to claim 1, wherein the end portion with the depression has a tip portion that faces in a direction different from a direction opposite to the protruding direction. The recessed end portion includes at least one first folded portion folded back in a direction opposite to the projecting direction, and at least one second folded portion folded back in the projecting direction,
The electric storage element according to claim 1, wherein the recess is located in the second folded portion. The electrical storage element according to any one of claims 1 to 3, wherein each of the separators adjacent to the electrode plate on both sides has the protruding portion including the recessed end portions facing each other with the electrode plate interposed therebetween. One of the separators adjacent to the electrode plate on both sides has the protrusion including the recessed end,
The electrical storage according to any one of claims 1 to 3, wherein the other separator includes a protruding portion that includes an end portion that overlaps the recessed end portion of the one separator and protrudes from an end portion of the electrode plate. element. The power storage device according to claim 5, wherein a tip end portion of the end portion of the other separator overlaps a tip end portion of the end portion with the depression of the one separator. The electrode plate is the positive electrode plate;
The negative electrode plate has a negative electrode protrusion that protrudes more than the positive electrode plate in the protrusion direction,
The power storage element according to claim 1, wherein the negative electrode protrusion is connected to an electrode terminal of the power storage element.

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