JP2018010781A - Power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress electrode sheets and a separator for constituting an electrode body of a power storage element from being folded/bent in a zig-zag like form.SOLUTION: A power storage element (1) according to the present invention comprises: an electrode body (20) having a first electrode sheet (21), a second electrode sheet (22), and a separator (23) individually arranged in parallel with a first direction (D1), of which the first and second electrode sheets are laminated over each other with the separator disposed therebetween in a second direction (D2) at right angles to the first direction; an outer packaging body (2) in which the electrode body is encased; and spacers (41, 42) interposed between the electrode body and inner faces of the outer packaging body. The spacers (41, 42) are disposed outside the electrode body (20) and opposed to each other in the second direction (D2), and have thrusting portions (51, 52, 55, 56) arranged so that each gradually thrusts inwardly in the second direction (D2) toward a leading end in the first direction (D1). In the electrode body (20), end faces (20a, 20b) in the first direction (D1) each front on a space (S1, S2).SELECTED DRAWING: Figure 6

Description

  The present invention relates to a power storage device having a positive electrode sheet and a negative electrode sheet that are laminated via a separator.

  In an electric storage element such as a lithium ion battery, an electrode body having a positive electrode sheet and a negative electrode sheet that are alternately stacked with separators may be used. This type of electrode body has an end surface composed of each edge of a positive electrode sheet, a negative electrode sheet, and a separator, and the end surface is electrically connected to an external terminal via a current collector.

  In addition, a spacer is provided between the electrode body of this type and the inner surface of the exterior body that accommodates the electrode body to electrically insulate them from each other and to absorb impacts caused by external forces. Sometimes.

  For example, Patent Document 1 discloses a configuration in which both end surfaces of a so-called wound electrode body are covered with a pair of spacers, and Patent Document 2 discloses an outer periphery of a pair of curved portions in the wound electrode body. A configuration in which spacers are arranged along the surface is disclosed.

JP2013-026214A JP 2006-040899 A

  However, when the spacer is disposed opposite to the end surface of the electrode body as in the electric storage element disclosed in Patent Document 1, when a pressing force is applied from the spacer to the end surface of the electrode body, the positive electrode sheet and the negative electrode of the electrode body The sheet or separator may be bent in a zigzag shape that contracts in a direction perpendicular to the end face.

  Therefore, there is a possibility that the positive electrode sheet and the negative electrode sheet are directly opposed to each other by causing the bent positive electrode sheet or the negative electrode sheet to break through the separator, or the position of the tip of the bent separator is shifted.

  Further, as in the power storage element disclosed in Patent Document 2, a spacer is interposed between the curved portion of the wound electrode body and the exterior body, but the end surface of the electrode body directly faces the inner surface of the exterior body. In this case, when the end surface of the electrode body comes into contact with the inner surface of the exterior body, there is a possibility that the above-described bending may occur in the positive electrode sheet, the negative electrode sheet, or the separator of the electrode body. obtain.

  Then, an object of this invention is to suppress the zigzag-shaped bending of the electrode sheet and separator which comprise the electrode body of an electrical storage element.

The electricity storage device according to the present invention is:
A first electrode sheet, a second electrode sheet having a polarity different from that of the first electrode sheet, and a separator interposed between the first electrode sheet and the second electrode sheet, the first electrode sheet, The second electrode sheet and the separator are respectively arranged in parallel to the first direction, and the first electrode sheet and the second electrode sheet are mutually in a second direction perpendicular to the first direction via the separator. An electrode body laminated on
An exterior body that houses the electrode body;
A spacer interposed between the electrode body and the inner surface of the exterior body,
The spacer has an overhanging portion that is disposed opposite to the outer side of the electrode body in the second direction, and gradually projects inward in the second direction toward the tip in the first direction.
The end face of the electrode body in the first direction faces the space.

  According to the present invention, the end face of the electrode body in the first direction faces the space, so that the end face of the electrode body is prevented from contacting the spacer and the spacer overhangs inward in the second direction. By restricting the movement of the electrode body in the first direction by the portion, the end surface of the electrode body is also prevented from contacting the inner surface of the exterior body. Therefore, when an external force is applied to the storage element, the pressing force is suppressed from acting on the end face of the electrode body. Thereby, it is suppressed that a 1st electrode sheet, a 2nd electrode sheet, and a separator bend zigzag, for example, and a short circuit between a 1st and 2nd electrode sheet is suppressed by extension.

  In addition, according to the present invention, the first electrode sheet, the second electrode sheet, and the separator stacked on each other can be guided by the protruding portion of the spacer so as to bend in the same direction (see FIGS. 6 and 10). Such bending in one direction is unlikely to cause a problem that the first electrode sheet and the second electrode sheet are directly opposed to each other without a separator therebetween, and therefore, a problem that hinders suppression of a short circuit is unlikely to occur.

  In the present invention, when each of the first electrode sheet and the second electrode sheet has an active material forming portion in which an active material layer is formed on the surface of the metal foil, the first electrode sheet and the second electrode sheet It is preferable that at least one of the active material forming part and the projecting part overlap in the first direction.

  In this case, in at least one of the first electrode sheet and the second electrode sheet, the portion cured by the formation of the active material layer is deformed so as to bend along the protruding portion of the spacer, whereby the protruding portion and the electrode body It is possible to increase the stress in the first direction that acts between the electrode body and the relative movement of the electrode body with respect to the spacer in the first direction.

  In the present invention, the first electrode sheet, the second electrode sheet, and the separator may be wound around a winding axis extending in the first direction.

  In this case, it is possible to suppress the pressing force from acting on the end face of the wound electrode body, and thus the above-described effect can be obtained in the wound electrode body.

  In the present invention, the exterior body may include a case body having an opening on at least one side in the first direction, and a lid that closes the opening.

  In this case, the above effect can be obtained in a so-called laterally wound electrode body. Further, when the electrode body and the spacer are inserted into the case body along the winding axis direction, the pressing force in the insertion direction can be suppressed from acting on the end surface of the electrode body. In addition, it is possible to suppress the electrode body from being damaged such that the first electrode sheet, the second electrode sheet, and the separator are bent in a zigzag shape, thereby improving the yield of the electrode bodies.

  In this invention, the said spacer may be provided over the full length of the said electrode body in the said 1st direction, and the said overhang | projection part may be provided in the both ends of the said spacer in the said 1st direction, respectively.

  In this case, zigzag bending of the first electrode sheet, the second electrode sheet, and the separator can be suppressed at both ends in the winding axis direction of the electrode body by one spacer.

  In the present invention, the electrode bodies are opposed to each other in the second direction, and extend in a third direction perpendicular to the first direction and the second direction, respectively, and between the pair of flat portions The spacer includes a first spacer that faces the outer peripheral surface of one of the curved portions and a second spacer that faces the outer peripheral surface of the other curved portion. Also good.

  In this case, in a state where the electrode body is sandwiched between the first spacer and the second spacer, the electrode body and the first and second spacers are arranged with respect to the case body while the first and second spacers are along the inner surface of the case body. Can be inserted easily.

  Further, at this time, the relative movement of the electrode body with respect to the first and second spacers in the insertion direction is restricted, so that the action of the pressing force on the end surface of the electrode body is suppressed, whereby the first electrode sheet, The zigzag bending of the two-electrode sheet and the separator can be effectively suppressed, and thereby the yield of the electrode body can be improved.

  Further, in this case, the first and second spacers interposed between the curved portions of the electrode body and the inner surface of the case body absorb the impact generated when an external force in the third direction is applied to the case body. Thus, the electrode body can be more effectively protected.

  In the present invention, the projecting portion may be an inclined surface inclined inward in the second direction toward the tip in the first direction.

  In this case, since the first electrode sheet, the second electrode sheet, and the separator are guided so as to be tilted inward in the second direction along the inclined surface of the spacer in the engagement portion with the protruding portion of the spacer in the electrode body, The end of the electrode body in the first direction can be stably deformed into a tapered shape while effectively suppressing the bending of these sheets in a zigzag shape.

  In the present invention, the projecting portion may be a curved surface curved so as to gradually increase the amount of projecting inward in the second direction toward the tip in the first direction.

  In this case, since the first electrode sheet, the second electrode sheet, and the separator are guided so as to be tilted inward in the second direction along the curved surface of the spacer in the engaging portion with the protruding portion of the spacer in the electrode body, The end of the electrode body in the first direction can be stably deformed into a tapered shape while effectively suppressing the bending of these sheets in a zigzag shape.

  In the present invention, the projecting portion may be provided on both sides of the electrode body in the second direction.

  In this case, the relative movement of the electrode body in the first direction with respect to the spacer is effectively restricted by the pair of projecting portions, so that the contact between the end surface of the electrode body and the inner surface of the exterior body can be more effectively suppressed.

  According to the present invention, it is possible to suppress zigzag bending of the first electrode sheet, the second electrode sheet, and the separator of the electrode body by suppressing the pressing force from acting on the end surface of the electrode body. A short circuit between the first and second electrode sheets can be suppressed.

It is a perspective view which shows the electrical storage element which concerns on 1st Embodiment of this invention. It is a disassembled perspective view of the electrical storage element shown in FIG. It is sectional drawing which shows the inside of the electrical storage element shown in FIG. It is a perspective view of the electrode body of the electrical storage element shown in FIG. It is a partially broken perspective view which shows the external terminal of a positive electrode, a collector, and these peripheral parts. FIG. 4 is a cross-sectional view taken along line AA of FIG. 3 showing the first spacer and its peripheral part. FIG. 5 is a cross-sectional view taken along the line BB in FIG. 3 showing the first spacer and its peripheral part. It is sectional drawing which shows the inside of the electrical storage element which concerns on 2nd Embodiment of this invention. It is a perspective view of the electrode body of the electrical storage element shown in FIG. It is sectional drawing similar to FIG. 6 which shows the electrical storage element which concerns on 3rd Embodiment of this invention. It is a perspective view of the electrode body of the electrical storage element shown in FIG.

  Hereinafter, with reference to an accompanying drawing, an electric storage element concerning the present invention is explained for every embodiment. It should be noted that the terms including “upper” and “lower” and terms related to these used to indicate directions in the present specification indicate directions in the posture of the electric storage element shown in the attached drawings. And does not necessarily coincide with the direction in the actual use state.

[First Embodiment]
1 and 2 show a power storage device 1 according to the first embodiment of the present invention. The power storage element 1 is a nonaqueous electrolyte secondary battery such as a lithium ion battery. However, the present invention can be applied to various power storage elements including capacitors in addition to the lithium ion battery.

  As illustrated in FIGS. 1 and 2, the power storage device 1 includes a case 2 having a substantially rectangular parallelepiped shape, for example. The case 2 includes a case main body 3 having an upper surface opening 3d and a lid 4 that closes the upper surface opening 3d of the case main body 3.

  The case body 3 includes a rectangular plate-like bottom wall 3a, a pair of long side walls 3b rising from the long side of the bottom wall 3a, and a pair of short side walls 3c rising from the short side of the bottom wall 3a. Upper ends of the pair of long side wall portions 3b and the pair of short side wall portions 3c define an upper surface opening 3d of the case main body 3.

  In the following description, the direction (the vertical direction in FIGS. 1 and 2) in which the bottom wall 3a and the upper surface opening 3d of the case body 3 face each other is referred to as a “first direction D1”, and the short side wall as viewed from the first direction D1. A direction parallel to the portion 3c is referred to as a “second direction D2”, and a direction parallel to the long side wall portion 3b when viewed from the first direction D1 is referred to as a “third direction D3”. That is, the first direction D1, the second direction D2, and the third direction D3 are perpendicular to each other.

  As the material of the case body 3, for example, a metal such as aluminum or an aluminum alloy is used. The surface of the case body 3 may be entirely covered with an insulating layer (not shown) made of, for example, resin.

  The lid 4 is a substantially rectangular metal plate. The lid 4 is provided with a gas discharge valve 8 for discharging the gas generated in the case body 3 to the outside of the case 2 and a liquid injection port (not shown). The liquid injection port is closed by a liquid injection stopper 10. The lid 4 is welded to the opening edge of the case body 3.

  A positive external terminal 11 and a negative external terminal 12 are fixed to the surface of the lid 4. For example, a metal such as aluminum, copper, or nickel is used as the material of the external terminals 11 and 12.

  As shown in FIG. 3, the external terminal 11 of the positive electrode has a flat plate portion 11a and a rivet portion 11b extending downward from the flat plate portion 11a. For example, by caulking the tip of the rivet portion 11b, the upper gasket 13 is interposed. Are fixed to the upper surface of the lid 4.

  Similarly, the negative external terminal 12 also has a flat plate portion 12a and a rivet portion 12b extending downward from the flat plate portion 12a. For example, the lid 4 is inserted through the upper gasket 13 by caulking the tip of the rivet portion 12b. It is fixed to the upper surface of the.

  As shown in FIGS. 2 and 3, the case 2 includes an electrode body 20 attached to the lid body 4, and first and second spacers 41 interposed between the outer peripheral surface of the electrode body 20 and the inner surface of the case 2. , 42 and an electrolytic solution (not shown) are accommodated.

  As shown in FIG. 4, the electrode body 20 includes a positive electrode sheet (corresponding to “first electrode sheet” in the claims) 21 and a negative electrode sheet 22 (in claims), each of which is a long strip having a constant width. 2) and two separators 23, 23 made of a microporous resin sheet are overlapped and wound into an oval shape having a generally high flatness.

  One of the two separators 23 and 23 is interposed between one layer of the positive electrode sheet 21 and one layer of the negative electrode sheet 22 adjacent thereto. The separators 23 and 23 are longer than the positive electrode sheet 21 and the negative electrode sheet 22. As a result, the outermost layer of the electrode body 20 is composed of either one of the separators 23.

  The winding axis (winding axis) of the positive electrode sheet 21, the negative electrode sheet 22, and the two separators 23 and 23 is conceptually indicated by the symbol X in FIG. The electrode body 20 is accommodated in the case body 3 in such a posture that the winding axis X extends substantially in the first direction D1 and the thickness direction of the electrode body 20 is disposed along the second direction D2 (FIG. 3). reference).

  The respective end portions of the electrode body 20 in the first direction D1 are end surface portions 20a and 20b on which the end portions in the width direction (short direction) of the positive electrode sheet 21, the negative electrode sheet 22, and the separators 23 and 23 are arranged. . The electrode body 20 is disposed so as to face the second direction D2 across the winding axis X, and extends in a straight line along the third direction D3, respectively, and a half when viewed from the first direction D1. It has a pair of curved portions 20d and 20d extending so as to be curved in a circular shape and connecting between the pair of flat portions 20c and 20c.

  The flat portion 20c is a portion that extends linearly in design. In the state in which the electrode body 20 is actually accommodated in the case 2, the flat portion 20c is not necessarily arranged in a completely linear shape, but in a state where it is bent so as to have a shape close to a straight line as a whole. Sometimes placed.

  As shown in FIGS. 2 and 3, in a state where the electrode body 20 is accommodated in the case 2, the long side wall portion 3 b of the case body 3 faces the outside of each flat portion 20 c of the electrode body 20, and each curved portion The short side wall 3c faces the outside of 20d, the bottom wall 3a faces the outside of the one end face 20b, and the lid 4 faces the outside of the other end face 20a.

  As shown in FIG. 4, the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23 of the electrode body 20 are stacked in the second direction D2 in the flat portion 20c, and in the third direction at the top of the curved portion 20d. D3 is laminated.

  The positive electrode sheet 21 includes a strip-shaped positive electrode metal foil 24 and an active material forming portion 25 in which a positive electrode active material layer is formed on both surfaces of the positive electrode metal foil 24. Edges on both sides in the width direction (short direction) of the positive electrode metal foil 24 are formed so as to extend linearly along the longitudinal direction of the positive electrode metal foil 24. On one side of the positive electrode metal foil 24 in the short direction (the lower side in FIG. 4), an active material forming portion 25 is provided up to the edge of the positive electrode metal foil 24.

  On the other edge (upper side in FIG. 4) in the short side direction of the positive electrode metal foil 24, an active material non-formation portion 34 exposing the positive electrode metal foil 24 is provided without providing the positive electrode active material layer. Yes. In the positive electrode sheet 21, the active material forming portion 25 is harder than the active material non-forming portion 34, and is difficult to bend.

  In addition, the positive electrode metal foil 24 is provided with a plurality of positive electrode tabs 35 protruding outward in the short direction from the active material non-forming portion 34 with an interval in the longitudinal direction. Each positive electrode tab 35 is an active material non-formation part in which an active material layer is not formed on the surface of the positive electrode metal foil 24, and is integrally connected to the active material non-formation part 34.

For example, aluminum is used as the material of the positive electrode metal foil 24, but other metals may be used. Examples of the positive electrode active material include lithium manganate (LiMn ₂ O ₄ ), nickel cobalt lithium manganate (LiNi _x Co _y Mn _1-xy O ₂ ), lithium cobaltate (LiCoO ₂ ), lithium nickelate ( LiNiO ₂ ), lithium iron phosphate (LiFePO ₄ ), lithium manganese phosphate (LiMnPO ₄ ), those using substitution additives, or mixtures thereof are used, but other lithium-containing transition metal oxides You may use thing.

  The negative electrode sheet 22 includes a strip-shaped negative electrode metal foil 26 and an active material forming portion 27 in which a negative electrode active material layer is formed on both surfaces of the negative electrode metal foil 26. Edges on both sides in the width direction (short direction) of the negative electrode metal foil 26 are formed so as to extend linearly along the longitudinal direction of the negative electrode metal foil 26. On both sides of the negative electrode metal foil 26 in the short direction (upper side and lower side in FIG. 4), the active material forming portion 27 is provided up to the edge of the negative electrode metal foil 26. Thereby, substantially the whole of each surface of the negative electrode metal foil 26 is covered with the negative electrode active material layer.

  A plurality of negative electrode tabs 37 similar to the positive electrode tabs 35 are provided on the negative electrode metal foil 26. In the short direction of the negative electrode metal foil 26, the negative electrode tab 37 protrudes on the same side as the positive electrode tab 35. Most of the negative electrode tab 37 excluding the base end portion is an active material non-formation portion where no active material layer is formed on the surface of the negative electrode metal foil 26.

For example, copper is used as the material of the negative electrode metal foil 26, but other metals may be used. As the negative electrode active material, for example, graphite is used, but other carbon materials, lithium metal, lithium alloy, lithium titanate (Li ₄ Ti ₅ O ₁₂ ), silicon, silicon monoxide, tin, and other materials capable of occluding lithium. Or mixtures thereof.

  The electrode body 20 in which the positive electrode sheet 21 and the negative electrode sheet 22 are overlapped and wound via separators 23 and 23 includes a positive electrode tab bundle 38 formed by laminating a plurality of positive electrode tabs 35.

  In the longitudinal direction of the negative electrode metal foil 26, the negative electrode tab 37 is arranged at a position that is displaced from the positive electrode tab 35, and the positive electrode tab 35 and the negative electrode tab 37 do not overlap each other. In the wound electrode body 20, the plurality of negative electrode tabs 37 are overlapped with each other, thereby forming a negative electrode tab bundle 39.

  The positive electrode tab bundle 38 and the negative electrode tab bundle 39 protrude from one end surface portion 20a of the electrode body 20 (the upper end surface portion in FIG. 4). Further, as viewed from the upper side in the first direction D1, the positive electrode tab bundle is formed from the flat portion 20c on one side (the front side in FIG. 4) with respect to the center line Y extending in the third direction D3 in the end surface portion 20a of the electrode body 20. 38 and the negative electrode tab bundle 39 protrude.

  As shown in FIG. 5, the positive electrode tab bundle 38 protruding from one flat portion 20c of the electrode body 20 is bent so that the tip side is tilted to the other flat portion 20c side in the second direction D2, for example, The current collector 15 is joined by ultrasonic welding. Accordingly, each positive electrode tab 35 is electrically connected to the positive external terminal 11 via the current collector 15.

  Although the illustration in FIG. 5 is omitted, the negative electrode tab bundle 39 is also bent and joined to the current collector 15 and electrically connected to the negative external terminal 12 through the current collector 15. (See FIG. 3).

  For example, the current collector 15 has the same shape in both the positive electrode and the negative electrode. The material of the current collector 15 may be different between the positive electrode and the negative electrode. For example, a metal such as aluminum is used for the material of the positive electrode current collector 15, and the material of the current collector 15 of the negative electrode is used. A metal such as copper is used.

  Each of the current collectors 15 includes, for example, a first flat plate portion 15a fixed to the lid body 4, a communication portion 15b that extends downward from the edge of the first flat plate portion 15a, and a communication portion 15b. And a second flat plate portion 15c that is connected to the first flat plate portion 15a and is opposed to the lower side of the first flat plate portion 15a.

  The first flat plate portion 15a is connected to the lower surface of the lid body 4 through the lower gasket 14, for example, the upper gasket 13, the lid body 4, the lower gasket 14 and the external terminals 11, 12 penetrating the first flat plate portion 15a from above. It is fixed by caulking at the lower ends of the rivet portions 11b and 12b (see FIG. 3), and is electrically connected to the external terminals 11 and 12 through the rivet portions 11b and 12b.

  The positive electrode tab bundle 38 and the negative electrode tab bundle 39 of the electrode body 20 are joined to the lower surface of the second flat plate portion 15c by, for example, ultrasonic welding, and are electrically connected to the electrode body 20 thereby.

  Hereinafter, the 1st and 2nd spacers 41 and 42 and the structure relevant to these spacers 41 and 42 are demonstrated.

  As shown in FIGS. 2 and 3, the first spacer 41 and the second spacer 42 are accommodated in the case body 3 together with the electrode body 20 in a state where the electrode body 20 is sandwiched from both sides in the third direction D3. The first spacer 41 is interposed between the outer peripheral surface of the curved portion 20d of the electrode body 20 and the inner surface of the short side wall portion 3c of the case body 3 on one side in the third direction (left side in FIGS. 2 and 3). The second spacer 42 is interposed between the outer peripheral surface of the curved portion 20d of the electrode body 20 and the inner surface of the short side wall portion 3c of the case body 3 on the other side in the third direction D3 (the right side in FIGS. 2 and 3). ing.

  As described above, the first and second spacers 41 and 42 are disposed along the end portion of the electrode body 20 in the third direction D3. The first and second spacers 41 and 42 are provided over the entire length of the electrode body 20 in the first direction D1. The first and second spacers 41 and 42 are configured to be line symmetric when viewed from the second direction D2.

  As shown in FIG. 2, each of the spacers 41 and 42 includes first and second side wall portions 43 and 44 as a pair of sandwiching portions that sandwich the end portion of the electrode body 20 in the third direction D3 from both sides in the second direction D2. And an outer wall 45 disposed outside the electrode body 20 in the third direction D3.

  The first and second side wall portions 43 and 44 are provided so as to extend in the first direction D1, and are longer than the electrode body 20 in the first direction D1. The outer side wall part 45 is provided so as to connect between the end parts of the first and second side wall parts 43 and 44 in the third direction D3. The outer side wall portion 45 is provided over the entire length of the first and second side wall portions 43 and 44 in the first direction D1.

  Each spacer 41, 42 is formed with a groove 46 that opens to the opposite side of the short side wall 3c of the case body 3 in the third direction D3 and extends in the first direction D1. The groove 46 is open to both end faces 47 and 48 of the spacers 41 and 42 in the first direction D1, and for example, U-shaped notches 47a and 48a are formed on the end faces 47 and 48, respectively.

  However, the notches 47 a and 48 a are not necessarily formed in the end surfaces 47 and 48 of the spacers 41 and 42, and both ends of the groove 46 may be closed at the end surfaces 47 and 48.

  As shown in FIGS. 3 and 6, the first and second side wall portions 43 and 44 and the outer side wall portion 45 of each spacer 41 and 42 are connected to the bottom wall portion 3a of the case body 3 and the lid body 4 in the first direction D1. It is arranged with almost no gap between them. The upper end surfaces 47 of the spacers 41 and 42 are disposed at right angles to the first direction D1, and are disposed in contact with the lower end of the lid body 4 so as to face each other with almost no gap. The lower end surface 48 of each spacer 41, 42 is disposed at right angles to the first direction D <b> 1 and is in contact with the upper surface of the bottom wall portion 3 a of the case body 3.

  As shown in FIGS. 6 and 7, the outer surfaces of the first and second side wall portions 43, 44 of the spacers 41, 42 are arranged at right angles to the second direction D <b> 2, It is arranged so as to be in contact with the inner surface of the portion 3b or almost without any gap.

  As shown in FIGS. 3 and 7, the outer surface of the outer wall portion 45 is disposed at a right angle to the third direction D3 and is in contact with the inner surface of the short side wall portion 3c of the case body 3 or almost without any gap. Has been placed. The outer side wall portion 45 is disposed so as to face the substantially entire surface of the short side wall portion 3c.

  As shown in FIG. 6, projecting portions 43 a and 43 b projecting inward in the second direction D <b> 2 are provided at both ends of the first side wall portion 43 in the first direction D <b> 1. Between these protrusion parts 43a and 43b, the thickness of the 1st side wall part 43 in the 2nd direction D2 is made substantially constant. The amount of protrusion of each protrusion 43a, 43b gradually increases toward the tip in the first direction D1.

  The inner surface 50 of the first side wall 43 is disposed in parallel to the first direction D1 in the portion where the protrusions 43a and 43b are not provided, and the first surface in the portion where the protrusions 43a and 43b are provided. The inclined surfaces 51 and 52 are inclined toward the second side wall portion 44 side (inside the second direction D2) toward the tip in the direction D1.

  Similar projecting portions 44a and 44b are provided at both ends of the second side wall portion 44 in the first direction D1, and the thickness of the second side wall portion 44 between these projecting portions 44a and 44b is substantially constant. ing. The amount of protrusion of each protrusion 44a, 44b gradually increases toward the tip in the first direction D1.

  The inner surface 54 of the second side wall portion 44 is also arranged in parallel to the first direction D1 in a portion where the projecting portions 44a and 44b are not provided, and in the portion where the projecting portions 44a and 44b are provided, the first surface D is provided. The inclined surfaces 55 and 56 are inclined toward the first side wall 43 side (in the second direction D2) toward the tip in the direction D1.

  The upper inclined surfaces 51 and 55 in the first and second side wall portions 43 and 44 are arranged to face each other with a gap in the second direction D2, and the lower inclined surfaces 52 and 56 are also arranged in the second direction D2. They are arranged opposite each other with an interval between them. The distance between the upper inclined surfaces 51 and 55 and the distance between the lower inclined surfaces 52 and 56 in the second direction D2 are gradually reduced toward the tip in the first direction D1.

  As a result, the upper narrow portion 61 in which the interval between the upper inclined surfaces 51 and 55 is gradually reduced as described above is provided at the upper end portion of each spacer 41 and 42, and the lower end portion of each spacer 41 and 42 is provided at the lower end portion of each spacer 41 and 42. As described above, the lower narrow portion 62 is provided in which the interval between the lower inclined surfaces 52 and 56 is gradually reduced.

  In the first and second side wall portions 43, 44, instead of the inclined surfaces 51, 52, 55, 56, for example, curved surfaces 251, 252, 255, 256 as shown by two-dot chain lines in FIG. May be formed. In this case, the curved surfaces 251, 252, 255, and 256 are formed to be curved so as to gradually increase the amount of protrusion inward in the second direction D 2 toward the tip in the first direction D 1. Narrow portions where the distances between the curved surfaces 251, 252, 255, 256 at D 2 are gradually reduced are formed at both ends of the spacers 41, 42 in the first direction D 1.

  As shown in FIG. 7, the inner surfaces 50 and 54 of the first and second side wall portions 43 and 44 are in the third direction D3 in the portions where the projecting portions 43a, 43b, 44a and 44b (see FIG. 6) are not provided. The inclined surface is inclined inward in the second direction D2 toward the front end. Thereby, the space | interval between the 1st and 2nd side wall parts 43 and 44 in the 2nd direction D2 is gradually reduced toward the front-end | tip of the 3rd direction D3.

  The electrode body 20 is sandwiched between the first and second side wall portions 43 and 44 of the spacers 41 and 42 in a portion extending from the end portion of the flat portion 20c to the curved portion 20d on both sides in the third direction D3. Thus, the case 2 is held by the spacers 41 and 42.

  As shown in FIGS. 3 and 6, the upper end surface portion 20 a of the electrode body 20 is disposed on the inner side in the first direction D <b> 1 with respect to the upper end surface 47 of the spacers 41 and 42, and the lower end surface portion of the electrode body 20. 20b is arranged inside the first direction D1 with respect to the lower end face 48 of the spacers 41 and 42. Thereby, both end surface parts 20a and 20b of the electrode body 20 face the spaces S1 and S2 over the entire surface, respectively.

  In the present embodiment, since the notches 47a and 48a (see FIG. 2) are provided in the end surfaces 47 and 48 of the spacers 41 and 42, the end surface portions 20a and 20b of the electrode body 20 form spaces S1 and S2. However, if the end surfaces 47 and 48 of the spacers 41 and 42 are closed, the end surface portions 20a and 20b of the electrode body 20 are connected to the spacers 41 and 42 via the spaces S1 and S2, respectively. 42 is disposed opposite to the inner surface of 42.

  The outer peripheral surface of the electrode body 20 is disposed to face the inner surfaces 50 and 54 of the first and second side wall portions 43 and 44 of the spacer 41 and 42 and the inner surface 58 of the outer wall portion 45 in the portions held by the spacers 41 and 42. Has been.

  As shown in FIG. 6, the outer peripheral surface of the electrode body 20 is disposed along the inner surfaces 50 and 54 of the first and second side wall portions 43 and 44 of the spacers 41 and 42, and abuts against the inner surfaces 50 and 54. Yes. In particular, in the narrow portions 61, 62 of the spacers 41, 42, the inclined surfaces 51, 52, the first and second side wall portions 43, 44 project gradually inward in the second direction D2 toward the tip in the first direction D1. The outer peripheral surface of the electrode body 20 is opposed to 55 and 56. Thereby, the outer peripheral surface of the electrode body 20 is disposed to be inclined with respect to the first direction D1 along the inclined surfaces 51, 52, 55, and 56 at both ends in the first direction D1.

  In the portions held by the narrow portions 61 and 62, the layers of the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23 constituting the electrode body 20 are inclined inward in the second direction D2 toward the tip in the first direction D1. It is inclined to. Thereby, both ends of the first direction D1 of the electrode body 20 are deformed in a tapered shape so that the dimension of the second direction D2 as a whole gradually decreases toward the tip of the first direction D1.

  As described above, the electrode body 20 held by the spacers 41 and 42 while being tapered at both ends in the first direction D1 contacts the spacers 41 and 42 and the case 2 at the end face portions 20a and 20b. Relative movement with respect to the spacers 41 and 42 in the first direction D1 is restricted by the narrow portions 61 and 62 of the spacers 41 and 42.

  Further, the inclined surfaces 51, 52, 55, 56 of the narrow portions 61, 62 and the active material forming portions 25, 27 (see FIG. 4) of the positive electrode sheet 21 and the negative electrode sheet 22 overlap in the first direction D1. ing. More specifically, the upper end portions of the active material forming portions 25 and 27 are disposed between the pair of inclined surfaces 51 and 55 in the upper narrow portion 61, and the pair of inclined surfaces 52 and 56 in the lower narrow portion 62. In the middle, the lower end portions of the active material forming portions 25 and 27 are arranged.

  That is, the positive electrode sheet 21 and the negative electrode sheet 22 are deformed so as to bend along the inclined surfaces 51, 52, 55, 56 of the spacers 41, 42 in the portion including the hard active material forming portions 25, 27. , 42 are held in narrow portions 61, 62. Therefore, the resistance against the tapered deformation of the electrode body 20 portion held by the narrow portions 61, 62 of the spacers 41, 42 is increased, and the inclined surfaces 51, 52, 55, 56 of the narrow portions 61, 62 and An increase in stress in the first direction D1 acting between the outer peripheral surface of the electrode body 20 is achieved. Thereby, the movement of the electrode body 20 to the 1st direction D1 is controlled more effectively.

  Therefore, when an external force in the first direction D1 is applied to the power storage element 1, the relative movement of the electrode body 20 with respect to the spacers 41 and 42 in the first direction D1 is restricted, so that the end surface portions 20a and 20b of the electrode body 20 are restricted. Can be kept facing the spaces S1, S2. Therefore, it is suppressed that the end surface parts 20a and 20b of the electrode body 20 contact the case 2 and the spacers 41 and 42, and thereby, it is suppressed that pressing force is applied to the end surface parts 20a and 20b of the electrode body 20. .

  Further, the tip side portions in the first direction D1 in the layers of the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23 of the electrode body 20 are spacers 41 and 42 on the respective sides in the second direction D2 across the winding axis X. Are inclined in the same direction along the inclined surfaces 51, 52, 55, and 56.

  Therefore, it can suppress effectively that each layer of the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23 of the electrode body 20 bends zigzag. Thereby, the positive electrode sheet 21 or the negative electrode sheet 22 is bent to break through the separator 23, or the separator 23 is bent and the position of the tip thereof is shifted, so that the positive electrode sheet 21 and the negative electrode sheet 22 are directly opposed to each other. Thus, a short circuit between the positive electrode sheet 21 and the negative electrode sheet 22 can be effectively suppressed.

  For example, as shown by a two-dot chain line in FIG. 3, the spacers 41 and 42 have inner sides of the third direction D3 at both ends of the outer wall 45 in the first direction D1 toward the tip in the first direction D1. An inclined surface 258 may be further provided. Accordingly, the narrow portions 61, 42 of the spacers 41, 42 are deformed so that the outer peripheral surface of the curved portion 20d of the electrode body 20 is inclined so as to incline in the third direction D3 toward the tip in the first direction D1. The electrode body 20 can be held more firmly by 62.

  As shown in FIG. 7, in the portions other than the narrow portions 61 and 62 (see FIG. 6) of the spacers 41 and 42, the curved portion 20 d of the electrode body 20 has the outer peripheral surface of the first and second spacers 41 and 42. The two side wall portions 43 and 44 are sandwiched between the first and second side wall portions 43 and 44 in a state of being deformed flat along the inclined inner surfaces 50 and 54. Thereby, the relative movement of the electrode body 20 with respect to the spacers 41 and 42 in the third direction D3 can be effectively suppressed.

  Further, the curved portion 20d faces the space S3 outside the third direction D3. The curved portion 20d preferably faces the space S3 at a portion including a circumferential position where the curvature is maximum, for example, the apex thereof.

  Thereby, when the external force of the 3rd direction D3 is applied to the electrical storage element 1, the impact input into the case main body 3 is absorbed by the spacers 41 and 42, and the electrode body 20 has the third direction D3 in the third direction D3. Since the impact is input through the inner surfaces 50 and 54 of the inclined spacers 41 and 42, the impact in the third direction D3 input to the electrode body 20 is effectively mitigated.

  Therefore, damage to the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23 can be suppressed in the curved portion 20 d where the stress due to the bending is applied to each layer of the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23.

  As shown in FIG. 2, during production, the electrode body 20 is assembled to the lid body 4 via the current collector 15 (see FIGS. 3 and 5), and then the first spacer 41, the second spacer 42, Is inserted into the case body 3 while being sandwiched from both sides in the third direction D3. In this insertion operation, the electrode body 20 is moved from the outer side of the lid body 4 while the outer surfaces of the outer wall portions 45 of the first and second spacers 41 and 42 are aligned with the inner surfaces of the pair of short side wall portions 3c of the case body 3. This is done by pushing in one direction D1.

  At the time of this insertion, the electrode body 20 is positioned in any of the first direction D1, the second direction D2, and the third direction D3 by the first and second spacers 41 and 42. Thus, the electrode body 20 can be easily inserted without contacting. Further, since no pressing force acts on the end face portions 20a and 20b of the electrode body 20, the zigzag bending of the positive electrode sheet 21, the negative electrode sheet 22 and the separator 23 of the electrode body 20 can be effectively suppressed. The yield of the electrode body 20 can be improved.

[Second Embodiment]
The configuration of the power storage device 101 according to the second embodiment will be described with reference to FIGS. 8 and 9. In the second embodiment, the description of the same components as those in the first embodiment is omitted, and the same reference numerals as those in the first embodiment are given in FIGS. 8 and 9.

  As shown in FIG. 8, the case 102 in the power storage device 101 of the second embodiment includes a rectangular tube-shaped case main body 103 having a pair of long side wall portions 3 b and a pair of short side wall portions 3 c, and an upper surface opening of the case main body 103. And an upper lid 104 that closes the opening, and a lower lid 105 that closes the lower surface opening of the case main body 103.

  As the material of the case body 103, for example, a metal such as aluminum or an aluminum alloy is used. The surface of the case body 103 may be entirely covered with an insulating layer (not shown) made of, for example, resin.

  The upper and lower lids 104 and 105 are substantially rectangular metal plates and are welded to the opening edge of the case main body 103.

  A negative external terminal 12 similar to that of the first embodiment is fixed to the upper lid 104, and a positive external terminal 111 integral with the upper lid 104 is provided so as to protrude upward. A negative electrode current collector 115 is fixed to the lower surface of the upper lid 104 via a lower gasket 14 by, for example, caulking.

  The negative electrode current collector 115 is integrally provided with a protruding portion 116 protruding downward. The projecting portion 116 is joined to a negative electrode lead portion 139 of the electrode body 120 to be described later, whereby the negative electrode external terminal 12 is electrically connected to the electrode body 120 via the negative electrode current collector 115. .

  The lower lid 105 is integrally provided with a protruding portion 106 that protrudes toward the inside of the case 102. The protruding portion 106 is joined to a positive electrode lead portion 138 of the electrode body 120 described later. Thereby, the positive electrode external terminal 111 is electrically connected to the electrode body 120 via the case 102.

  As shown in FIG. 9, the electrode body 120 is obtained by overlapping and winding the positive electrode sheet 21, the negative electrode sheet 22, and the two separators 23, 23, similarly to the electrode body 20 of the first embodiment. Part of the configuration of the positive electrode sheet 21 and the negative electrode sheet 22 is different from that of the first embodiment.

  An active material non-formation part 134 exposing the positive electrode metal foil 24 is provided on the edge of the positive electrode sheet 21 on one side (lower side in FIG. 9) without providing the positive electrode active material layer. Yes. The active material forming portion 25 of the positive electrode sheet 21 is harder than the active material non-forming portion 134 and is difficult to bend. The positive electrode sheet 21 is not provided with the positive electrode tab 35 (see FIG. 4) as in the first embodiment.

  In the second embodiment, the negative electrode sheet 22 is also provided with an active material non-formation part 136. The active material forming portion 27 of the negative electrode sheet 22 is harder than the active material non-forming portion 136 and is difficult to bend. The active material non-formation part 136 of the negative electrode sheet 22 is provided at the edge of the negative electrode sheet 22 on the side opposite to the active material non-formation part 134 (upper side in FIG. 9). The negative electrode sheet 37 is not provided with the negative electrode tab 37 (see FIG. 4) as in the first embodiment.

  The winding of the positive electrode sheet 21, the negative electrode sheet 22 and the separators 23, 23 around the winding axis X is such that the active material non-formation part 134 of the positive electrode sheet 21 is in the first direction D1 more than the negative electrode sheet 22 and the separators 23, 23. The active material non-forming part 136 of the negative electrode sheet 22 protrudes to the other side in the first direction D1 (upper side of FIG. 9) than the positive electrode sheet 21 and the separators 23, 23. It is performed in a state where they are superimposed.

  The electrode body 120 formed in this way is arranged to face the second direction D2 across the winding axis X, and each of the pair of flat portions 120c, 120c extending linearly along the third direction D3, A pair of curved portions 120d and 120d extending so as to be bent in a semicircular shape when viewed from one direction D1 and connecting the pair of flat portions 120c and 120c are provided.

  On one side of the electrode body 120 in the first direction D1 (the lower side in FIG. 9), a positive electrode lead portion 138 is formed by overlapping only the active material non-formation portion 134 of the positive electrode sheet 21, and the positive electrode lead portion 138 is formed. Thus, an end surface portion 120b on one side of the electrode body 120 is configured.

  On the other side of the electrode body 120 in the first direction D1 (upper side in FIG. 9), a negative electrode lead part 139 is formed by superimposing only the active material non-formation part 136 of the negative electrode sheet 22, and the negative electrode lead part 139 The other end face 120a of the electrode body 120 is configured.

  The positive electrode lead portion 138 is formed of a wound body obtained by winding the active material non-forming portion 134 around the winding axis X. Similarly, the negative electrode lead portion 139 is formed of a wound body in which the active material non-forming portion 136 is wound around the winding axis X.

  As shown in FIG. 8, a protruding portion 106 of the lower lid 105 is inserted into the inner peripheral side of the positive electrode lead portion 138, and the protruding portion 106 and the positive electrode lead portion 138 are joined by, for example, ultrasonic welding. Thus, the electrode body 120 is electrically connected to the positive electrode external terminal 111 via the lower lid body 105, the case main body 103, and the upper lid body 104.

  A protruding portion 116 of the negative electrode current collector 115 is inserted into the inner peripheral side of the negative electrode lead portion 139, and the protruding portion 116 and the negative electrode lead portion 139 are joined by, for example, ultrasonic welding, so that the electrode body 120 is joined. Is electrically connected to the negative electrode external terminal 12 via the negative electrode current collector 115.

  Between the outer peripheral surface of the electrode body 120 configured as described above and the inner surface of the case 102, first and second spacers 41 and 42 similar to those in the first embodiment are interposed. Therefore, the electrode body 120 is held at both ends in the first direction D1 by the narrow portions 61 and 62 of the spacers 41 and 42, so that the relative movement with respect to the spacers 41 and 42 in the first direction D1 is restricted. Thus, the same effect as in the first embodiment can be obtained.

  In the second embodiment, the portion including the negative electrode lead portion 139 of the electrode body 120 is held by the upper narrow portion 61 of the spacers 41 and 42, and the portion including the positive electrode lead portion 138 of the electrode body 120 is the lower side of the spacers 41 and 42. The narrow portion 62 is held.

  As in the first embodiment, the inclined surfaces 51, 52, 55, 56 (see FIG. 6) of the narrow portions 61, 62 and the active material forming portions 25, 27 of the positive electrode sheet 21 and the negative electrode sheet 22 (see FIG. 9). And overlap in the first direction D1. More specifically, the upper end portions of the active material forming portions 25 and 27 are arranged between the pair of inclined surfaces 51 and 55 in the upper narrow portion 61, and between the pair of inclined surfaces 52 and 56 in the lower narrow portion 62. Are arranged at the lower ends of the active material forming portions 25, 27.

  Accordingly, the electrode body 120 is held by the narrow portions 61 and 62 of the spacers 41 and 42 in a state where the resistance to the tapered deformation is increased in the portion including the hard active material forming portions 25 and 27. Therefore, the stress in the first direction D1 acting between the inclined surfaces 51, 52, 55, 56 of the narrow portions 61, 62 and the outer peripheral surface of the electrode body 120 is increased, whereby the spacer in the first direction D1. The relative movement of the electrode body 120 with respect to 41 and 42 can be more effectively regulated.

  In the second embodiment, the active material forming portions 25 of both the positive electrode sheet 21 and the negative electrode sheet 22 with respect to the inclined surfaces 51, 52, 55, 56 of the narrow portions 61, 62 of the spacers 41, 42, respectively. 27 overlaps in the first direction D1, but the active material forming portions 25, 27 of either the positive electrode sheet 21 or the negative electrode sheet 22 may overlap in the first direction D1. For example, the active material forming portion 25 of only the positive electrode sheet 21 overlaps with the inclined surfaces 51 and 55 of the upper narrow portion 61 in the first direction D1, and the negative electrode with respect to the inclined surfaces 52 and 56 of the lower narrow portion 62. The active material forming part 27 of only the sheet 22 may overlap in the first direction D1.

  In the second embodiment, the positive external terminal 111 is connected to the electrode body 120 through the bottom of the case 102, and the negative external terminal 12 is connected to the electrode body 120 through the current collector 115 on the upper surface side of the case 102. However, the positive electrode external terminal 111 may be connected to the electrode body through the current collector on the upper surface side of the case, and the negative electrode external terminal 12 may be connected to the electrode body through the bottom of the case.

[Third Embodiment]
The configuration of the electricity storage device 201 according to the third embodiment will be described with reference to FIGS. 10 and 11. In the third embodiment, the description of the same components as those in the first embodiment is omitted, and the same reference numerals as those in the first embodiment are given in FIGS. 10 and 11.

  The power storage device 201 according to the third embodiment has a so-called stacked electrode body 220 instead of the so-called wound electrode bodies 20 and 120 as in the first and second embodiments.

  As shown in FIG. 11, the electrode body 220 includes a plurality of positive electrode sheets (corresponding to “first electrode sheet” in the claims) 221 and a plurality of negative electrode sheets (“second electrode sheets” in the claims). Equivalent) 222 is a laminated body in which the separators 223 are alternately laminated. Each positive electrode sheet 221 includes an active material non-forming portion 34 and a positive electrode tab 35 similar to the above, and each negative electrode sheet 222 includes a negative electrode tab 37 similar to the above.

  As shown in FIG. 10, the electrode body 220 has a posture in which the positive electrode sheet 221, the negative electrode sheet 222, and the separator 223 are arranged in parallel to the first direction D1 and the third direction D3 and stacked in the second direction D2. Is housed in. Similar to the first embodiment, the electrode body 220 includes a positive electrode tab bundle formed by stacking the positive electrode tabs 35 and a negative electrode tab bundle formed by stacking the negative electrode tabs 37, and the external terminals 11 via the current collectors 15. , 12 (see FIG. 3).

  The power storage device 201 according to the third embodiment also includes the first spacer 41 and the second spacer 42 (see FIGS. 2 and 3) similar to those in the first embodiment, and the electrode body 220 includes the first and second spacers. 41 and 42 are accommodated in the case 2 while being sandwiched from both sides in the third direction D3. Both ends of the electrode body 220 in the first direction D1 are held by the narrow portions 61 and 62 of the spacers 41 and 42 as in the first embodiment.

  As a result, the electrode body 220 is moved in the first direction D1 by the inclined surfaces 51, 52, 55, 56 of the spacers 41, 42 gradually projecting inward in the second direction D2 toward the tip in the first direction D1. In addition to being restricted, the entire end faces 220a and 220b in the first direction D1 face the spaces S1 and S2.

  Therefore, also in the electrical storage element 201 of the third embodiment having the stack-type electrode body 220, the positive electrode sheet 221 and the negative electrode sheet are suppressed by suppressing the pressing force from acting on the end surface portions 220a and 220b of the electrode body 220. For example, it is possible to obtain the same effect as that of the first embodiment, such as the fact that 222 and the separator 223 are bent in a zigzag shape, for example.

  In the third embodiment, the stack-type electrode body 220 is connected to the positive and negative external terminals via the current collector on the upper surface of the case, but one of the positive and negative external terminals is connected to the upper surface of the case. The other external terminal may be connected to the electrode body 220 through the bottom of the case.

  While the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments.

  For example, in the above-described embodiment, the spacers 41 and 42 are provided over the entire length of the electrode bodies 20 and 120 in the first direction D1, and the upper and lower narrow portions 61 and 62 are configured by the same spacers 41 and 42. However, the upper and lower narrow portions 61 and 62 may be formed of separate spacers, and these spacers may be arranged with a gap in the first direction D1.

  In the above-described embodiment, the example in which the narrow portions 61 and 62 on one side in the third direction D3 and the narrow portions 61 and 62 on the other side are configured by separate spacers 41 and 42 has been described. The narrow portions on both sides of the direction D3 may be configured with the same spacer.

  Furthermore, in the above-described embodiment, the inner surfaces 50 and 54 of the first and second side wall portions 43 and 44 are configured to be smoothly continuous over the entire surface. The example in which the facing portions of the inner surfaces 50, 54 of the first and second side wall portions 43, 44 are opposed to each other without contact or almost without any gap has been described. 54 may be provided with a convex portion, a concave portion, a notch or an opening, and the inner surfaces 50, 54 may not contact the outer peripheral surface of the electrode bodies 20, 120 at a part of the portion facing the electrode bodies 20, 120. It may be arranged so as to face each other with almost no gap.

  Furthermore, in the first and second embodiments described above, the present invention has been described by taking the so-called laterally wound electrode bodies 20 and 120 having the winding axis X extending in the first direction D1 as an example. Can be applied to a so-called longitudinally wound electrode body having a winding axis extending in the third direction D3, for example.

1: Power storage element 2: Case (exterior body)
3: Case main body 3a: Bottom wall portion 3b: Long side wall portion 3c: Short side wall portion 4: Lid 11: Positive electrode external terminal 12: Negative electrode external terminal 15: Current collector 20: Electrode body 20a, 20b: End face portion 20c: Flat part 20d: curved part 21: positive electrode sheet (first electrode sheet)
22: Negative electrode sheet (second electrode sheet)
23: Separator 24: Positive electrode metal foil 25: Active material forming part 26: Negative electrode metal foil 27: Active material forming part 34, 36: Active material non-forming part 41: First spacer 42: Second spacer 43: First side wall part 44: 2nd side wall part 45: Outer wall part 51,55: Inclined surface (overhang | projection part)
52, 56: Inclined surface (overhang portion)
61, 62: Narrow part 101: Power storage element 102: Case (exterior body)
103: Case body 104: Upper lid body 105: Lower lid body 106: Projection part 111: Positive electrode external terminal 115: Negative electrode current collector 116: Projection part 120: Electrode body 120a, 120b: End face part 120c: Flat part 120d: Curved part 134,136: Active material non-formation part 138: Positive electrode lead part 139: Negative electrode lead part 220: Electrode body 220a, 220b: End face part 221: Positive electrode sheet (first electrode sheet)
222: Negative electrode sheet (second electrode sheet)
223: Separator 251, 255: Curved surface (overhang portion)
252 and 256: curved surface (overhang portion)
D1: First direction D2: Second direction D3: Third direction S1, S2, S3: Space X: Winding axis

Claims (9)

A first electrode sheet, a second electrode sheet having a polarity different from that of the first electrode sheet, and a separator interposed between the first electrode sheet and the second electrode sheet, the first electrode sheet, The second electrode sheet and the separator are respectively arranged in parallel to the first direction, and the first electrode sheet and the second electrode sheet are mutually in a second direction perpendicular to the first direction via the separator. An electrode body laminated on
An exterior body that houses the electrode body;
A spacer interposed between the electrode body and the inner surface of the exterior body,
The spacer has an overhanging portion that is disposed opposite to the outer side of the electrode body in the second direction, and gradually projects inward in the second direction toward the tip in the first direction.
The electric storage element, wherein an end face of the electrode body in the first direction faces a space. The first electrode sheet and the second electrode sheet each have an active material forming part in which an active material layer is formed on the surface of a metal foil,
The active material forming part and the projecting part in at least one of the first electrode sheet and the second electrode sheet overlap with each other in the first direction. Power storage element.   3. The power storage device according to claim 1, wherein the first electrode sheet, the second electrode sheet, and the separator are wound around a winding axis that extends in the first direction. .   The power storage element according to claim 3, wherein the exterior body includes a case main body having an opening on at least one side in the first direction, and a lid that closes the opening. The spacer is provided over the entire length of the electrode body in the first direction;
The power storage element according to claim 4, wherein the projecting portions are provided at both end portions of the spacer in the first direction. The electrode body is opposed to each other in the second direction, and a pair of flat portions extending in a third direction perpendicular to the first direction and the second direction, respectively, and a pair of flat portions connecting the pair of flat portions A curved portion,
The power storage according to claim 5, wherein the spacer includes a first spacer facing an outer peripheral surface of one of the curved portions, and a second spacer facing the outer peripheral surface of the other curved portion. element.   7. The power storage device according to claim 1, wherein the projecting portion is an inclined surface that is inclined inward in the second direction toward the tip in the first direction. 8. .   7. The projecting portion according to claim 1, wherein the projecting portion is a curved surface that is curved so as to gradually increase the projecting amount inward in the second direction toward the tip in the first direction. The electrical storage element of Claim 1.   9. The power storage device according to claim 1, wherein the protruding portion is provided on both sides of the electrode body in the second direction.

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