JP2017201590A - Power storage element and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage element which can suppress the decrease in the extrusion amount of a separator extruding from between active material layers put over each other in a laminating direction of electrodes in an electrode body; and a method for manufacturing the power storage element.SOLUTION: Disclosed are a power storage element and a method for manufacturing the power storage element. The power storage element comprises: an electrode body 2 having electrodes 23, 24 including active material layers 232, 242 respectively, and a separator 25, and arranged by laminating the electrodes 23, 24 and the separator 25. The separator 25 is fixed to the electrodes 23, 24 outside a region where the active material layers 232, 242 are put over each other in a laminating direction of the electrodes 23, 24 in a direction orthogonal to the laminating direction.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a power storage element including an electrode body in which an electrode and a separator are stacked, and a method for manufacturing the power storage element.

  Conventionally, a lithium ion secondary battery including a wound electrode body is known (see Patent Document 1). In this lithium ion secondary battery, the wound electrode body is housed in a battery case together with a non-aqueous electrolyte.

  The wound electrode body is an electrode body obtained by stacking and winding a positive electrode sheet having a positive electrode active material layer and a negative electrode sheet having a negative electrode active material layer while interposing a separator composed of a porous resin. . In this wound electrode body, an active material layer between the positive electrode sheet and the negative electrode sheet (specifically, between the positive electrode active material layer and the negative electrode active material layer overlapping in the stacking direction of the positive electrode sheet and the negative electrode sheet). ) Protrudes from the separator. And from the part which protruded from the active material layer of the said positive electrode sheet | seat and the said negative electrode sheet | seat in the said separator, the non-aqueous electrolyte solution in a battery case (the non-aqueous liquid which has accumulated in the battery case without being hold | maintained at the winding electrode body) By absorbing the electrolyte solution, the nonaqueous electrolyte solution is supplied to the winding center portion of the wound electrode body and the center portion in the winding center axis direction.

  In this wound electrode body, since the separator is made of resin, when the temperature of the wound electrode body rises due to charge / discharge of the lithium ion secondary battery, the separator may shrink. When the separator shrinks in this way, the amount of protrusion of the separator protruding from the active material layer overlapping in the stacking direction in the wound electrode body is reduced, and the contact area with the non-aqueous electrolyte in the battery case is reduced. The non-aqueous electrolyte solution cannot be sufficiently absorbed. In this case, since the non-aqueous electrolyte is not sufficiently supplied to the winding center part of the winding electrode body and the center part in the winding center axis direction, the battery performance is deteriorated.

JP2015-41589A

  In view of the above, an object of the present invention is to provide a power storage device capable of suppressing a decrease in the amount of protrusion of the separator protruding from the active material layer overlapping in the electrode stacking direction in the electrode body, and a method for manufacturing the power storage device. .

The electricity storage device according to the present invention is:
An electrode body including an active material layer and a separator, and an electrode body on which the electrode and the separator are stacked;
The separator is fixed to the electrode on the outer side in the direction orthogonal to the stacking direction of the region where the active material layers overlap in the stacking direction of the electrode and the separator.

  According to such a configuration, since the separator is fixed to the electrode that does not easily shrink due to heat or the like outside the region where the active material layers in the electrode body overlap, when the separator attempts to shrink due to heat or the like, the active material layer Intrusion of the part of the separator that protrudes from the active material layer is suppressed, thereby suppressing a decrease in the amount of protrusion of the separator from the active material layer.

The power storage element is
You may provide the metal member which has a convex part which penetrates into the said electrode body in the position where the said separator is fixed to the said electrode.

  According to such a configuration, the fixing of the separator to the electrode is firmly maintained by the convex portion of the metal member.

Further, in the power storage element,
A current collecting member connected to a region different from a region where the active material layer of the electrode is disposed;
The metal member may be disposed at a distance from the current collecting member.

  The current collecting member easily rises in temperature due to current flowing during charging and discharging of the storage element, but according to such a configuration, it is possible to prevent heat generated in the current collecting member from being transmitted to the separator via the metal member. it can.

In addition, the power storage element is
An electrolyte,
A case for accommodating the electrolytic solution and the electrode body,
In the electrode body, the stacked electrode and separator are wound,
The separator may be fixed to the electrode at an end portion of the electrode body in the winding central axis direction.

  In such an electrode body (a so-called wound electrode body), the amount of protrusion of the separator is secured at the end of the electrode body in the winding center axis direction, so that the electrode body in the winding center axis direction in the case is secured. Contact between the separator and the electrolytic solution at the end is ensured, whereby the electrolytic solution is suitably supplied to the winding center of the wound electrode body.

in this case,
It is preferable that the separator is fixed to the electrode at both ends in the winding central axis direction of the electrode body.

  According to such a configuration, since the contact between the separator and the electrolytic solution is ensured at both ends in the winding center axis direction of the electrode body, the electrolytic solution is more suitably applied to the winding center portion of the wound electrode body. Supplied.

In addition, a method for manufacturing a power storage device according to the present invention includes:
Laminating an electrode including an active material layer and a separator to form an electrode body;
Fixing the separator to the electrode outside the direction orthogonal to the stacking direction of the region where the active material layers overlap in the stacking direction of the electrode and the separator.

  According to such a configuration, in the manufactured energy storage device, the separator is fixed to the electrode that does not easily shrink due to heat or the like outside the region where the active material layers in the electrode body overlap with each other. Occasionally, the portion of the separator protruding from the active material layer is prevented from entering the active material layer, thereby suppressing a decrease in the amount of protrusion of the separator from the active material layer.

In the method of manufacturing the electricity storage device,
In the fixing of the separator to the electrode, a state in which the convex portion of the metal member enters the electrode body at a position where the separator is fixed to the electrode may be formed.

  According to such a configuration, in the manufactured power storage device, the fixing of the separator to the electrode is firmly maintained by the convex portion of the metal member.

Further, in the method for manufacturing the power storage element,
In fixing the separator to the electrode, the convex portion may be formed by mechanical clinching in a state where the metal member is overlapped with the stacked electrode and the separator.

  According to this configuration, the fixing of the separator to the electrode is suitably maintained by plastic deformation of the metal member. In other words, the fixing (joining) structure using plastic deformation (mechanical clinch) of the metal member sufficiently maintains the strong fixing of the separator to the electrode.

The manufacturing method of the electricity storage element is:
Connecting a current collecting member to the electrode,
The current collecting member and the metal member may be integrated.

  According to this configuration, the metal member (or current collecting member) is positioned by connecting the electrode and the current collecting member (or fixing the separator to the electrode), which facilitates mechanical clinching (or connection). Easier to do).

  As described above, according to the present invention, it is possible to provide a power storage element capable of suppressing a decrease in the amount of protrusion of the separator protruding from the active material layer overlapping in the electrode stacking direction in the electrode body, and a method for manufacturing the power storage element. it can.

FIG. 1 is a perspective view of a power storage device according to this embodiment. FIG. 2 is an exploded perspective view of the power storage element. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is a diagram for explaining an electrode body of the electricity storage element. FIG. 5 is a diagram for explaining a positive electrode, a negative electrode, and a separator that constitute the electrode body. FIG. 6 is a view for explaining a joined state between the electrode body and the current collector. FIG. 7 is an enlarged cross-sectional view of a connection portion between the one part of the current collector and the electrode body. FIG. 8 is a diagram showing a flow of a method for manufacturing the power storage element. FIG. 9 is a diagram for explaining the mechanical clinch. FIG. 10 is a diagram for explaining the mechanical clinch. FIG. 11 is an enlarged view of a portion A in FIG. FIG. 12 is a diagram for explaining a joined state between an electrode body and a current collector according to another embodiment. FIG. 13 is an exploded perspective view of the electricity storage device according to the other embodiment. FIG. 14 is a perspective view of a power storage device including the power storage element.

  Hereinafter, an embodiment of a power storage device according to the present invention will be described with reference to FIGS. Examples of the power storage element include a primary battery, a secondary battery, and a capacitor. In the present embodiment, a chargeable / dischargeable secondary battery will be described as an example of a power storage element. In addition, the name of each component (each component) of this embodiment is a thing in this embodiment, and may differ from the name of each component (each component) in background art.

  The electricity storage device of this embodiment is a nonaqueous electrolyte secondary battery. More specifically, the power storage element is a lithium ion secondary battery that utilizes electron transfer that occurs as lithium ions move. This type of power storage element supplies electrical energy. One or a plurality of power storage elements are used. Specifically, the storage element is used singly when the required output and the required voltage are small. On the other hand, when at least one of a required output and a required voltage is large, the power storage element is used in a power storage device in combination with another power storage element. In the power storage device, a power storage element used in the power storage device supplies electric energy.

  As shown in FIGS. 1 to 4, the power storage element includes electrodes 23 and 24 including active material layers 232 and 242 and a separator 25, and the electrodes 23 and 24 and the separator 25 are stacked. An electrode body 2 is provided. The power storage device 1 includes a case 3 that houses the electrode body 2, an external terminal 4 that is at least partially disposed outside the case 3, and a current collector 5 that electrically connects the electrode body 2 and the external terminal 4. And an insulating member 6 for insulating between the electrode body 2 and the case 3. In the electricity storage device 1 of the present embodiment, the active material layer includes the positive electrode active material layer 232 and the negative electrode active material layer 242, and the electrode includes the positive electrode 23 and the negative electrode 24.

  The electrode body 2 includes a winding core 21 and a laminated body 22 in which the positive electrode 23 and the negative electrode 24 are laminated in a mutually insulated state, and the laminated body 22 is wound around the winding core 21. (See FIGS. 3 and 4). As the lithium ions move between the positive electrode 23 and the negative electrode 24 in the electrode body 2, the power storage device 1 is charged and discharged.

  The winding core 21 is usually formed of an insulating material. The core 21 of the present embodiment has a cylindrical shape, more specifically, a flat cylindrical shape. The winding core 21 is formed by winding a sheet having flexibility or thermoplasticity. The sheet of the present embodiment is formed of a synthetic resin.

  As shown in FIG. 5, the positive electrode 23 includes a strip-shaped metal foil 231 and a positive electrode active material layer 232 stacked on the metal foil 231. The positive electrode active material layer 232 is overlaid on the metal foil 231 in a state in which one end edge portion (uncovered portion) in the width direction (short direction: left and right direction in FIG. 5) of the metal foil 231 is exposed. ing. The metal foil 231 of the present embodiment is, for example, an aluminum foil. In the positive electrode 23, the positive electrode active material layers 232 are respectively disposed on both surfaces of the metal foil 231, that is, in the positive electrode 23, in the thickness direction, The foil 231 is sandwiched between the positive electrode active material layers 232.

  The positive electrode active material layer 232 includes a positive electrode active material and a binder.

The positive electrode active material is, for example, a lithium metal oxide. Specifically, the positive electrode active material is, for example, _a composite oxide (Li _a Co _y O ₂ , Li _a Ni _x ) represented by Li _a Me _b O _c (Me represents one or more transition metals). O ₂ , Li _a Mn _z O ₄ , Li _a Ni _x Co _y Mn _z O _2, etc.), Li _a Me _b (XO _c ) _d (Me represents one or more transition metals, and X represents, for example, P , Si, B, a polyanion compounds represented by the representative of the _{V) (Li a Fe b PO} 4, Li a Mn b PO 4, Li a Mn b SiO 4, Li a Co b PO 4 F , etc.). The positive electrode active material of this embodiment is LiNi _1/3 Co _1/3 Mn _1/3 O ₂ .

  Examples of the binder used for the positive electrode active material layer 232 include polyvinylidene fluoride (PVDF), a copolymer of ethylene and vinyl alcohol, polymethyl methacrylate, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyacrylic acid, and polymethacrylic acid. Acid, styrene butadiene rubber (SBR). The binder of this embodiment is polyvinylidene fluoride.

  The positive electrode active material layer 232 may further include a conductive additive such as ketjen black (registered trademark), acetylene black, or graphite. The positive electrode active material layer 232 of this embodiment has acetylene black as a conductive additive.

  The negative electrode 24 includes a strip-shaped metal foil 241 and a negative electrode active material layer 242 stacked on the metal foil 241. This negative electrode active material layer 242 has an edge portion (non-covered portion) on the other side (opposite side of the non-covered portion of the metal foil 231 of the positive electrode 23) of the metal foil 241 in the width direction (short direction: left-right direction in FIG. 5). ) With the metal foil 241 being exposed. The metal foil 241 of the present embodiment is, for example, a copper foil. In the negative electrode 24, the negative electrode active material layers 242 are respectively disposed on both surfaces of the metal foil 241. That is, in the negative electrode 24, a metal is formed in the thickness direction. The foil 241 is sandwiched between the negative electrode active material layers 242. The dimension in the width direction of the negative electrode active material layer 242 of this embodiment is larger than the dimension in the width direction of the positive electrode active material layer 232.

  The negative electrode active material layer 242 includes a negative electrode active material and a binder.

  The negative electrode active material is, for example, a material that causes an alloying reaction with carbon materials such as graphite, non-graphitizable carbon, and graphitizable carbon, or lithium ions such as silicon (Si) and tin (Sn). The negative electrode active material of this embodiment is non-graphitizable carbon.

  The binder used for the negative electrode active material layer 242 is the same as the binder used for the positive electrode active material layer 232. The binder of this embodiment is polyvinylidene fluoride.

  The negative electrode active material layer 242 may further include a conductive additive such as ketjen black (registered trademark), acetylene black, or graphite. The negative electrode active material layer 242 of this embodiment does not have a conductive additive.

  In the electrode body 2 of the present embodiment, the positive electrode 23 and the negative electrode 24 configured as described above are wound in a state where they are insulated by the separator 25. That is, in the electrode body 2 of this embodiment, the laminated body 22 of the positive electrode 23, the negative electrode 24, and the separator 25 is wound.

  The separator 25 is an insulating member and is disposed between the positive electrode 23 and the negative electrode 24. Thereby, in the electrode body 2 (specifically, the laminated body 22), the positive electrode 23 and the negative electrode 24 are insulated from each other. The separator 25 holds the electrolytic solution in the case 3. Thereby, at the time of charging / discharging of the electrical storage element 1, a lithium ion can move between the positive electrode 23 and the negative electrode 24 which are alternately laminated on both sides of the separator 25.

The separator 25 has a band shape, and is constituted by a porous film such as polyethylene, polypropylene, cellulose, polyamide, and the like. In the separator 25 of the present embodiment, an inorganic layer containing inorganic particles such as SiO ₂ particles, Al ₂ O ₃ particles, boehmite (alumina hydrate) is provided on a substrate formed of a porous film. It is formed with. The base material of the separator 25 of this embodiment is formed of, for example, polyethylene.

  The dimension of the separator 25 in the width direction (left-right direction in FIG. 5) is larger than the width of the negative electrode active material layer 242. In the separator 25, the positive electrode 23 and the negative electrode 24 are stacked in a state where the positive electrode active material layer 232 and the negative electrode active material layer 242 are displaced in the width direction so as to overlap with each other in the thickness direction (stacking direction: vertical direction in FIG. 5). Between. At this time, a portion where the metal foil 231 of the positive electrode 23 is exposed (a portion where the positive electrode active material layer 232 does not overlap: an exposed portion) and a portion where the metal foil 241 of the negative electrode 24 is exposed (the negative electrode active material layer 242 does not overlap). (Site: exposed site) does not overlap. That is, the exposed portion of the positive electrode 23 protrudes from the region where the positive electrode 23 and the negative electrode 24 overlap in the width direction (direction perpendicular to the stacking direction), and the exposed portion of the negative electrode 24 overlaps the positive electrode 23 and the negative electrode 24. Projecting in the width direction (the direction opposite to the projecting direction of the exposed portion of the positive electrode 23). The electrode body 2 is formed by winding the positive electrode 23, the negative electrode 24, and the separator 25 (that is, the stacked body 22) stacked in such a state. In this wound state, the separator 25 has electrodes (this embodiment) outside the region where the active material layers overlap (in the example of this embodiment, the positive electrode active material layer 232 and the negative electrode active material layer 242). In this example, both the positive electrode 23 and the negative electrode 24 are fixed (see FIG. 6). For this reason, the separator 25 of this embodiment has the positive electrode active material layer 232 and the negative electrode active material layer 242 corresponding to the region where the structure for fixing the separator 25 to the electrodes 23 and 24 is formed (see α in FIG. 5). Projecting in a direction perpendicular to the stacking direction from a region (see β in FIG. 5) overlapping in the stacking direction. Details of the fixing structure of the separator 25 to the electrodes 23 and 24 will be described later. Further, in the electrode body 2 of the present embodiment, the uncoated laminated portion 26 in the electrode body 2 is configured by a portion where only the exposed portion of the positive electrode 23 or the exposed portion of the negative electrode 24 is laminated.

  The uncoated laminated portion 26 is a portion that is electrically connected to the current collector 5 in the electrode body 2. The uncoated laminated portion 26 of the present embodiment has two portions sandwiching the hollow portion 27 (see FIGS. 2 and 4) when viewed from the winding central axis direction of the wound positive electrode 23, negative electrode 24, and separator 25. It is divided into parts (divided uncoated laminated parts) 261.

  The uncoated laminated portion 26 configured as described above is provided on each electrode of the electrode body 2. That is, the uncoated laminated portion 26 in which only the exposed portion of the positive electrode 23 is laminated constitutes the non-coated laminated portion of the positive electrode in the electrode body 2, and the uncoated laminated portion 26 in which only the exposed portion of the negative electrode 24 is laminated. 2 constitutes the non-coated laminated portion of the negative electrode.

  The case 3 includes a case main body 31 having an opening and a cover plate 32 that closes (closes) the opening of the case main body 31. The case 3 houses the electrolytic solution in the internal space 33 (see FIG. 3) together with the electrode body 2 and the current collector 5 and the like. Case 3 is formed of a metal having resistance to the electrolytic solution. The case 3 of the present embodiment is formed of an aluminum metal material such as aluminum or an aluminum alloy, for example.

The electrolytic solution is a non-aqueous electrolytic solution. The electrolytic solution is obtained by dissolving an electrolyte salt in an organic solvent. Examples of the organic solvent include cyclic carbonates such as propylene carbonate and ethylene carbonate, and chain carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. The electrolyte salt is LiClO ₄ , LiBF ₄ , LiPF ₆ or the like. The electrolyte solution of this embodiment is prepared by mixing 1 mol / L LiPF ₆ in a mixed solvent in which propylene carbonate, dimethyl carbonate, and ethyl methyl carbonate are adjusted at a ratio of propylene carbonate: dimethyl carbonate: ethyl methyl carbonate = 3: 2: 5. Is dissolved.

  As shown in FIGS. 1 to 3, the case 3 is formed by joining the opening peripheral edge portion 34 of the case main body 31 and the peripheral edge portion of the lid plate 32 in an overlapped state. In the case 3, an internal space 33 is defined by the case main body 31 and the lid plate 32. In the case 3 of this embodiment, the opening peripheral part 34 of the case main body 31 and the peripheral part of the cover plate 32 are joined by welding.

  The case main body 31 includes a plate-like closing part 311 and a cylindrical body part 312 connected to the periphery of the closing part 311.

  The closing part 311 is located at the lower end of the case body 31 when the case body 31 is arranged with the opening facing upward (that is, the bottom wall of the case body 31 when the opening faces upward). ) Part. The blocking part 311 has a rectangular shape when viewed from the normal direction of the blocking part 311.

  Hereinafter, the long side direction of the blocking part 311 is defined as the X-axis direction, the short side direction of the blocking part 311 is defined as the Y-axis direction, and the normal direction of the blocking part 311 is defined as the Z-axis direction.

  The body portion 312 has a rectangular tube shape, more specifically, a flat rectangular tube shape. The body portion 312 has a pair of long wall portions 313 extending from the long side at the periphery of the closing portion 311 and a pair of short wall portions 314 extending from the short side at the periphery of the closing portion 311. That is, the pair of long wall portions 313 are opposed to each other with an interval in the Y-axis direction (specifically, an interval corresponding to the short side of the periphery of the closing portion 311), and the pair of short wall portions 314 are spaced in the X-axis direction. (In detail, they are opposed to each other with a gap corresponding to the long side of the periphery of the blocking portion 311). By connecting the end portions of the short wall portion 314 corresponding to the pair of long wall portions 313 (specifically, facing each other in the Y-axis direction), a rectangular tube-shaped body portion 312 is formed.

  As described above, the case body 31 has a rectangular tube shape (that is, a bottomed rectangular tube shape) in which one end portion in the opening direction (Z-axis direction) is closed.

  The lid plate 32 is a plate-like member that closes the opening of the case body 31. Specifically, the cover plate 32 has a contour shape corresponding to the opening peripheral edge 34 of the case body 31 when viewed from the Z-axis direction. That is, the lid plate 32 is a rectangular plate material that is long in the X-axis direction when viewed from the Z-axis direction. The cover plate 32 contacts the case body 31 so as to close the opening of the case body 31. More specifically, the peripheral edge of the cover plate 32 is overlapped with the open peripheral edge 34 of the case body 31 so that the cover plate 32 closes the opening. In a state where the opening peripheral edge 34 and the cover plate 32 are overlapped, the boundary portion between the cover plate 32 and the case main body 31 is welded. Thereby, the case 3 is configured.

  The external terminal 4 is a part that is electrically connected to an external terminal of another power storage element or an external device. The external terminal 4 is formed of a conductive member. For example, the external terminal 4 is formed of a highly weldable metal material such as an aluminum-based metal material such as aluminum or an aluminum alloy, or a copper-based metal material such as copper or a copper alloy. The external terminal 4 of this embodiment has a surface 41 to which a bus bar or the like can be welded.

  The current collector 5 is disposed in the case 3 and is directly or indirectly connected to the electrode body 2 so as to be conductive. As shown in FIGS. 2, 3, and 6, the current collector 5 of the present embodiment is connected to the electrode body 2 through a clip member 55 so as to be conductive. That is, the electric storage element 1 includes a clip member 55 that connects the electrode body 2 and the current collector 5 so as to be conductive. The clip member 55 is sandwiched so as to bundle the positive electrode 23 or the negative electrode 24 laminated in the uncoated laminated portion 26 (specifically, the bisected uncoated laminated portion 261) of the electrode body 2. As a result, the clip member 55 is formed between the positive electrodes 23 (specifically, portions not overlapping the separator 25 in the exposed portion of the positive electrode 23) or the negative electrode 24 (specifically, the exposed negative electrode 24). The part) which does not overlap with the separator 25 in the part) is made conductive. The clip member 55 of the present embodiment is formed by bending a plate-shaped metal material so that a cross section along the XY plane (a plane including the X axis and the Y axis) becomes a U-shape. . In the present embodiment, two clip members 55 are disposed on the positive electrode of the electrode body 2 and two clip members 55 are disposed on the negative electrode.

  The current collector 5 is formed of a conductive member and is disposed along the inner surface of the case 3. The current collector 5 of this embodiment makes the external terminal 4 and the clip member 55 conductive. Specifically, the current collector 5 includes a current collector body (collector) including a first connection portion 51 that is connected to the external terminal 4 so as to be conductive, and a second connection portion 52 that is connected to the electrode body 2 so as to be electrically conductive. Electrical member) 50 and a piece (metal member) 53 used to fix the separator 25 to the electrodes 23 and 24. In the current collector 5, the first connection portion 51 extends in the X-axis direction along the cover plate 32 from the vicinity of the boundary between the cover plate 32 and the short wall portion 314 in the case 3, and the second connection portion 52 has the first connection portion 52. The one connecting portion 51 extends in the Z-axis direction from the end portion on the boundary side along the long wall portion 313 (specifically, a portion of the long wall portion 313 near the boundary with the short wall portion 314). Further, the piece portion 53 extends from the second connection portion 52 along the long wall portion 313 in the X-axis direction. Details are as follows.

  The first connection portion 51 is connected to the external terminal 4 so that energization is possible. Specifically, the first connection portion 51 is a plate-like portion that extends in the X-axis direction along the inner surface of the case 3 (lid plate 32) while being insulated from the case 3 (specifically, the lid plate 32). That is, the first connection portion 51 extends in the X-axis direction along the cover plate 32 between the cover plate 32 and the electrode body 2. The external terminal 4 is connected to the distal end portion of the first connection portion 51 (the end portion on the opposite side to the boundary position between the cover plate 32 and the short wall portion 314) (see FIG. 3).

  The second connection part 52 is connected to the electrode body 2 (in the example of the present embodiment, through the clip member 55) so as to be conductive. The second connection portion 52 extends in the Z-axis direction from the first connection portion 51 along the inner surface of the case 3 (long wall portion 313) while being insulated from the case 3 (specifically, the long wall portion 313). Specifically, the second connecting portion 52 is connected to the electrode body 2 from both ends in the Y-axis direction of the portion near the boundary of the first connecting portion 51 (the portion near the boundary between the cover plate 32 and the short wall portion 314). This is a plate-like portion extending in the Z-axis direction along the non-coated laminated portion 26 so as to sandwich the uncoated laminated portion 26 in the Y-axis direction. That is, the second connection part 52 is connected to the electrode body 2 (non-covered) between the long wall part 313 and the electrode body 2 (uncoated laminated part 26) on one side in the Y-axis direction of the electrode body 2 from the first connection part 51. The electrode body 2 (non-covered) extends in the Z-axis direction along the coated laminated portion 26) and between the long wall portion 313 and the electrode body 2 (uncoated laminated portion 26) on the other side of the electrode body 2 in the Y-axis direction. It extends in the Z-axis direction along the laminated part 26). The second connection portion 52 is electrically connected to the electrode body 2 (uncoated laminated portion 26) by being joined to the clip member 55. The second connection portion 52 of the present embodiment is mechanically clinched at a plurality of positions spaced in the Z-axis direction in a state where the second connection portion 52 is overlapped with the clip member 55 in a state of sandwiching the uncoated laminated portion 26 (see FIG. 6) clinch junction site 521). Thereby, the current collector 5 is connected (fixed) to the electrode body 2. In addition, joining of the 2nd connection part 52 and the clip member 55 is not limited to a mechanical clinch, Ultrasonic joining, welding, etc. may be sufficient. Further, the current collector 5 in FIG. 2 is in a state before mechanical clinching (clinch joining).

  The piece portion 53 is a plate-like portion extending in the X-axis direction from the second connection portion 52 along the surface of the electrode body 2 between the electrode body 2 and the long wall portion 313. This piece 53 extends to a position where the tip overlaps the end of the separator 25 in the width direction (X-axis direction). The piece 53 is a region on the outer side in the X-axis direction of the region where the active material layers 232 and 242 overlap in the stacking direction (Y-axis direction) of the electrodes 23 and 24, and the separator 25 and the electrodes 23 and 24. In the region where the exposed portion overlaps in the Y-axis direction, these electrodes 23 and 24 (exposed portion) and the separator 25 are mechanically clinched (clinch joined) (see clinch joined portion 530 in FIG. 6). The plate-like piece 53 is plastically deformed by this mechanical clinching, and as shown in FIG. 7, a protrusion 531 that enters the electrode body 2 is formed in the piece 53. Thereby, the separator 25 is fixed to the electrodes 23 and 24. At this time, a plate-like member 54 having a concave portion 541 having a shape corresponding to the convex portion 531 is disposed at a position sandwiching the exposed portion of the stacked electrodes 23 and 24 and the separator 25 with respect to the convex portion 531. ing. In the electricity storage device 1 of the present embodiment, the separator 25 is fixed to the electrodes 23 and 24 at the ends of the electrode body 2 in the winding central axis direction (X-axis direction). More specifically, a plurality of pieces 53 are provided on each of the current collector 5 arranged on the positive electrode side and the current collector 5 arranged on the negative electrode side (in the example shown in the present embodiment, each second Two pieces 53 are provided in the connecting portion 52), and each piece 53 is used to fix the separator 25 to the electrodes 23 and 24. Therefore, the separator 25 is fixed to the electrodes 23 and 24 at a plurality of locations at both ends of the electrode body 2 in the winding center axis direction.

  The current collector 5 configured as described above is disposed on each of the positive electrode and the negative electrode of the power storage device 1 as described above. In the power storage device 1 of the present embodiment, the case 3 is disposed in the positive electrode uncoated laminated portion 26 and the negative electrode uncoated laminated portion 26 of the electrode body 2, respectively.

  The positive electrode current collector 5 and the negative electrode current collector 5 are formed of different materials. Specifically, the positive electrode current collector 5 is formed of, for example, aluminum or an aluminum alloy, and the negative electrode current collector 5 is formed of, for example, copper or a copper alloy.

  As shown in FIGS. 2 and 3, the insulating member 6 is disposed between the case 3 (specifically, the case main body 31) and the electrode body 2. The insulating member 6 of the present embodiment is formed in a bag shape by bending an insulating sheet-like member cut into a predetermined shape.

  Next, the manufacturing method of the electrical storage element 1 is demonstrated, also referring FIG.

  First, the electrodes 23 and 24 including the active material layers 232 and 242 are stacked via the separator 25, whereby the electrode body 2 is formed (step S1). Specifically, the laminate 22 in which the positive electrode 23 and the negative electrode 24 are laminated via the separator 25 is wound around the core 21, whereby the electrode body 2 is formed.

  Next, the current collector 5 and the external terminals 4 are assembled to the cover plate 32 (step S2). Subsequently, the electrode body 2 is connected to the current collector 5. In the connection of the current collector 5 to the electrode body 2, the step of fixing the separator 25 to the electrodes 23 and 24 (step S 3), and the current collector main body 50 is connected to the electrode body 2 (specifically, the uncoated laminate of the positive electrode 23. A step (step S4) of conducting to the portion 26 or the non-coated laminated portion 26 of the negative electrode 24).

  Specifically, in the step of fixing the separator 25 to the electrodes 23 and 24, in the electrode body 2, the separator 25 is disposed outside the region where the active material layers 232 and 242 overlap in the stacking direction of the electrodes 23 and 24. Fixed to. Details are as follows.

  A bundle of exposed portions of the electrodes 23 and 24 stacked at the end in the winding center axis direction of the electrode body 2 (that is, the undivided uncoated stacked portion 261 of the electrode body 2) is sandwiched between the clip members 55. . In this state, the piece 53 of the current collector 5 is overlaid on the portion where the exposed portions of the electrodes 23 and 24 and the separator 25 overlap in the stacking direction and the active material layers 232 and 242 are not disposed. It is done. Further, a plate-like member 54 is disposed in the hollow portion 27 of the electrode body 2 so as to sandwich the portion where the exposed portion of the electrodes 23 and 24 and the separator 25 overlap with each other. (See FIG. 9). Subsequently, the exposed portions of the overlapping electrodes 23 and 24, the separator 25, the piece 53, and the plate-like member 54 are joined by mechanical clinching. As shown in FIGS. 9 and 10, this mechanical clinch bonding is performed by overlapping the uncoated laminated portion 261 (the portion where the exposed portion of the electrodes 23, 24 and the separator 25 overlap, and the active material layer 232, 242), a part of the piece 53 and the plate-like member 54 are pushed into a female die (die) 81 by a male die (punch) 80, whereby the piece 53 is Bending locally (forming the convex portion 531) and pressing the member (in the example of this embodiment, the concave portion 541 of the plate-like member 54) and the interlocking portion (convex portion) formed by the bending. The diameter-enlarged portion at 531 (see FIG. 11) is joined by engaging the 532 through the bisected uncoated laminated portion 261 (engaged with irregularities). In the example of the present embodiment, joining by two mechanical clinch is performed on one uncoated laminated portion 261 (see reference numeral 530 in FIG. 6). Moreover, in this embodiment, joining by mechanical clinch is performed in a state where the female mold 81 is disposed in the hollow portion 27 and the male mold 80 is disposed outside. In the joining portion (fixed portion) between the separator 25 and the electrodes 23 and 24, the separator 25 exists between the piece 53 that is a part of the current collector 5 and the electrodes 23 and 24. Conduction between the electrode bodies 2 cannot be obtained (or sufficient conduction cannot be obtained).

  Next, in the step of conducting the current collector body 50 to the electrode body 2, the second connection portion 52 and the clip member 55 in a state of sandwiching the uncoated laminated portion 261 are joined by mechanical clinch. This mechanical clinching is the same as the mechanical clinching performed in the process of fixing the separator 25 to the electrodes 23 and 24. In the example of the present embodiment, joining by one mechanical clinch is performed on one second connection portion 52 (see reference numeral 521 in FIG. 6). At the joint part (fixed part) between the second connection part 52 (current collector body 50) and the electrodes 23, 24, the second connection part 52, which is a part of the current collector 5, and the electrodes 23, 24 are in contact. Therefore, sufficient conduction between the current collector 5 and the electrode body 2 can be obtained.

  As described above, when the two current collectors 5 are connected to the electrode body 2, the electrode body 2 and the current collector 5 assembled in the cover plate 32 are covered with the insulating member 6. The electrode body 2, the current collector 5, and the like covered with are inserted into the case body 31. Then, in a state where the opening of the case main body 31 is closed by the cover plate 32, the boundary portion between the case main body 31 and the cover plate 32 is welded (for example, laser welding) (step S5), whereby the power storage device 1 is Complete.

  According to the power storage device 1 described above, the separator 25 is fixed to the electrodes 23 and 24 that are not easily contracted by heat or the like outside the region where the active material layers 232 and 242 overlap in the electrode body 2. Therefore, the entry of the portion of the separator 25 protruding from between the active material layers 232 and 242 into the active material layers 232 and 242 is suppressed. Thereby, the reduction | decrease of the protrusion amount between the active material layers 232 and 242 of the separator 25 is suppressed.

  Further, in the power storage device 1 of the present embodiment, the metal convex portion 531 enters the electrode body 2 at a position where the separator 25 is fixed to the electrodes 23 and 24. For this reason, in the electrical storage element 1, fixation to the electrodes 23 and 24 of the separator 25 is maintained firmly.

  In the electricity storage device 1 of the present embodiment, the separator 25 is fixed to the electrodes 23 and 24 at the end of the electrode body 2 in the winding center axis direction. In such an electrode body 2 (so-called wound electrode body 2), the amount of protrusion of the separator 25 is ensured at the end of the electrode body 2 in the winding center axis direction. Contact between the separator 25 and the electrolytic solution (a so-called surplus electrolytic solution that is not held by the separator 25 and is accumulated in the case 3) at the end in the winding central axis direction is ensured. Thereby, in the electrical storage element 1, the electrolyte is suitably supplied to the winding center portion of the winding electrode body 2.

  In the method for manufacturing the electricity storage device 1 of this embodiment, the separator 25 is fixed to the electrodes 23 and 24 by mechanical clinching. Thereby, in the electrical storage element 1, the fixing of the separator 25 to the electrodes 23 and 24 is suitably maintained by the plastic deformation of the piece 53. That is, the fixing of the separator 25 to the electrodes 23 and 24 is sufficiently maintained by the fixing (joining) structure using plastic deformation (mechanical clinch) of the metal piece 53.

  In the electricity storage device 1 of the present embodiment, the current collector main body 50 and the piece 53 are integrated. For this reason, the current collector body 50 is positioned with respect to the electrode body 2 by fixing the separator 25 to the electrodes 23 and 24 at the time of manufacturing the power storage element 1. This eliminates the need to adjust the relative positions of the electrode body 2 and the current collector body 50 during connection, and as a result, the connection between the electrode body 2 and the current collector body 50 can be reduced. It becomes easy.

  In addition, the electrical storage element of this invention and the manufacturing method of an electrical storage element are not limited to the said embodiment, Of course, various changes can be added in the range which does not deviate from the summary of this invention. For example, the configuration of another embodiment can be added to the configuration of a certain embodiment, and a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of an embodiment can be deleted.

  In the electricity storage device 1 of the above-described embodiment, the separator 25 is fixed to the electrodes 23 and 24 by mechanical clinch (clinch bonding), but is not limited to this configuration, and the active material layer 232 by other bonding methods such as adhesion, It may be fixed to the electrodes 23, 24 outside the 242.

  In the electricity storage device 1 of the above embodiment, the separator 25 is fixed to the electrodes 23 and 24 by the convex portion 531 formed by mechanical clinch (clinch joining), but the configuration is not limited thereto. The separator 25 may be fixed to the electrodes 23 and 24 by a metal rivet or the like. In other words, the separator 25 only needs to be fixed to the electrodes 23 and 24 by metal protrusions that enter the stacking direction of the electrodes 23 and 24 with respect to the electrode body 2.

  In the electricity storage device 1 of the above embodiment, the separator 25 is fixed to the electrodes 23 and 24 by mechanical clinching at both ends of the electrode body 2 in the winding central axis direction, but the configuration is not limited thereto. The separator 25 is fixed to the electrodes 23 and 24 by mechanical clinching only at one end in the winding center axis direction of the electrode body 2, and the separator 25 is fixed to the electrodes 23 and 24 by other fixing means at the other end. It may be fixed.

  In the electricity storage device 1 of the above-described embodiment, the electrode body 2 is a so-called wound type in which the laminated belt-like electrodes 23 and 24 are wound, but is not limited to this configuration. The electrode body 2 may be a so-called laminated type in which sheet-like electrodes are laminated. In this case, the separator 25 may be fixed to the electrodes 23 and 24 at any position in the circumferential direction at the peripheral edge of the sheet-like electrode. For example, if the sheet-like electrode is a square shape, the separator 25 may be fixed to the electrodes 23 and 24 at positions corresponding to the sides of the square shape. It may be performed at a position corresponding to.

  In the electricity storage device 1 of the above embodiment, the current collector main body 50 and the piece 53 are integrated, but the configuration is not limited thereto. For example, as shown in FIGS. 12 and 13, the current collector main body 50 and the piece 53 may be separate and may be arranged with a space therebetween. The current collector main body (a member or part for conducting the external terminal 4 and the electrode body 2) 50 easily rises in temperature when a current flows during charging / discharging of the power storage element 1. Heat generated in the body main body 50 can be prevented from being transmitted to the separator 25 via the one part (metal member used for fixing the separator 25 to the electrodes 23 and 24) 53.

  In separator 25 of the above-mentioned embodiment, although an inorganic layer is provided on a substrate formed of a porous film, it is not limited to this configuration. For example, the separator 25 may be composed only of a base material formed of a porous film. In the case of the separator 25 having no inorganic layer, the shrinkage of the separator 25 due to heat is larger than that of the separator having the inorganic layer. Therefore, the separator 25 is fixed to the electrodes 23 and 24, whereby the electrodes 23 and 24 in the electrode body 2 are fixed. The effect of suppressing the reduction in the amount of protrusion of the separator 25 protruding from between the active material layers 232 and 242 overlapping in the stacking direction becomes more remarkable.

  Moreover, in the said embodiment, although the case where an electrical storage element was used as a nonaqueous electrolyte secondary battery (for example, lithium ion secondary battery) which can be charged / discharged was demonstrated, the kind and magnitude | size (capacity | capacitance) of an electrical storage element are arbitrary. It is. Moreover, in the said embodiment, although the lithium ion secondary battery was demonstrated as an example of an electrical storage element, it is not limited to this. For example, the present invention can be applied to various secondary batteries, other primary batteries, and power storage elements of capacitors such as electric double layer capacitors.

  The power storage element (for example, battery) 1 may be used in a power storage device 11 (a battery module when the power storage element is a battery) 11 as shown in FIG. The power storage device 11 includes at least two power storage elements 1 and a bus bar member 12 that electrically connects two (different) power storage elements 1 to each other. In this case, the technique of the present invention only needs to be applied to at least one power storage element 1.

  DESCRIPTION OF SYMBOLS 1 ... Power storage element, 2 ... Electrode body, 21 ... Core, 22 ... Laminated body, 23 ... Positive electrode (electrode), 231 ... Metal foil, 232 ... Positive electrode active material layer (active material layer), 24 ... Negative electrode (electrode) 241 ... Metal foil, 242 ... Negative electrode active material layer (active material layer), 25 ... Separator, 26 ... Uncoated laminate part, 261 ... Divided uncoated laminate part, 27 ... Hollow part, 3 ... Case, 31 ... Case main body, 311 ... Closure part, 312 ... Body part, 313 ... Long wall part, 314 ... Short wall part, 32 ... Cover plate, 33 ... Internal space, 34 ... Opening peripheral edge part, 4 ... External terminal, 41 ... Surface, 5 ... Current collector, 50 ... Current collector body (current collector member), 51 ... First connection portion, 52 ... Second connection portion, 521 ... Clinch joint part, 53 ... Single part (metal member), 530 ... Clinch joint Site, 531 ... convex portion, 55 ... clip member, 6 ... insulating member, 11 ... power storage device, 12 ... bus Member, 80 ... male mold, 81 ... female mold

Claims (9)

An electrode body including an active material layer and a separator, and an electrode body on which the electrode and the separator are stacked;
The power storage element, wherein the separator is fixed to the electrode outside in a direction orthogonal to a stacking direction of a region where the active material layers overlap in the stacking direction of the electrode and the separator.   The electrical storage element according to claim 1, comprising a metal member having a convex portion that enters the electrode body at a position where the separator is fixed to the electrode. A current collecting member connected to a region different from a region where the active material layer of the electrode is disposed;
The power storage element according to claim 2, wherein the metal member is disposed at a distance from the current collecting member. An electrolyte,
A case for accommodating the electrolytic solution and the electrode body,
In the electrode body, the stacked electrode and separator are wound,
The electricity storage device according to any one of claims 1 to 3, wherein the separator is fixed to the electrode at an end portion in a winding central axis direction of the electrode body.   The electrical storage element according to claim 4, wherein the separator is fixed to the electrode at both ends of the electrode body in the winding central axis direction. Laminating an electrode including an active material layer and a separator to form an electrode body;
Fixing the separator to the electrode outside the direction orthogonal to the stacking direction of a region where the active material layers overlap in the stacking direction of the electrode and the separator in the stacking direction of the electrode and the separator. Method.   The method for manufacturing a power storage element according to claim 6, wherein the fixing of the separator to the electrode forms a state in which a convex portion of a metal member enters the electrode body at a position where the separator is fixed to the electrode.   The power storage element manufacturing according to claim 7, wherein in fixing the separator to the electrode, the convex portion is formed by mechanical clinching in a state where the metal member is overlapped with the stacked electrode and the separator. Method. Connecting a current collecting member to the electrode,
The method for manufacturing a power storage element according to claim 7, wherein the current collecting member and the metal member are integrated.