JP6655865B2 - Storage element - Google Patents

Description

  The present invention relates to a power storage device.

Conventionally, various power storage elements are known. For example, as a power storage element, a power storage element has been proposed in which a positive electrode and a negative electrode each formed in a sheet shape are provided as electrodes, and the positive electrode and the negative electrode face each other.
In this type of power storage device, for example, each of a positive electrode and a negative electrode is stacked on each other with a separator interposed therebetween.

An example of this type of power storage element is described in Patent Document 1, for example. The power storage element described in Patent Literature 1 includes a positive electrode and a negative electrode stacked on each other as electrodes. Further, in such a power storage element, the negative electrode includes an electrode base plate (negative electrode base plate) including a sheet-shaped current collecting base material and active material layers each including an active material and disposed on both sides of the current collecting base material. , By being cut in the thickness direction.
Therefore, in such a power storage element, since a plurality of negative electrodes are formed from the negative electrode original plate, the production efficiency per negative electrode is better than when one negative electrode is formed one by one.

In the power storage device described in Patent Literature 1, since the negative electrode is formed by cutting the negative electrode original plate, the current collecting base material is bent at least at a part of the end by the cutting force. It has an end.
The bent end portion of the negative electrode is formed by applying a cutting force toward one side in the thickness direction when cutting the negative electrode original plate. Therefore, at the bent end portion of the negative electrode, the current collecting base material is bent toward one side in the thickness direction of the negative electrode while extending to the edge of the negative electrode.
Therefore, as described above, the power storage element described in Patent Document 1 includes the efficiently manufactured negative electrode, but at the bent end of the negative electrode, the current-collecting base material is disposed on one side in the thickness direction of the negative electrode. Bent to the side.

By the way, in the power storage device described in Patent Document 1, in order to suppress a short circuit between the positive electrode and the negative electrode, the current collecting base material of the positive electrode is not bent at the end of the positive electrode, and the edge of the positive electrode is not bent. It extends straight. Specifically, in such a power storage element, at the bent end of the negative electrode laminated with the positive electrode, although the current collecting base material of the negative electrode is bent to the positive electrode side, the current collection of the positive electrode extending straight to the edge of the positive electrode The substrate extends only inside the bent end of the negative electrode.
Therefore, in such a power storage element, although the current collecting base material of the negative electrode is bent toward the positive electrode side at the bent end portion of the negative electrode, the current collecting base material at the bent end portion of the negative electrode is the current collecting base material of the positive electrode. Not facing edge. Thereby, the end of the current collecting base material of the negative electrode is prevented from contacting the current collecting base material of the positive electrode, and the short circuit between the positive electrode and the negative electrode is suppressed.

  However, in the power storage device described in Patent Document 1, only the negative electrode of the positive electrode and the negative electrode is formed by cutting the electrode plate. Therefore, in such a storage element, although the short circuit between the positive electrode and the negative electrode is suppressed as described above, the production efficiency of the electrodes is not necessarily good because only one electrode is formed by cutting the electrode base plate. Not something. That is, in such a power storage element, although the short circuit between the electrodes is suppressed, the current collection base material is formed by cutting the electrode base plate and the current collection base material is bent, and the electrode having a good production efficiency is one of the electrodes. There is a problem that it is adopted only for the electrode.

International Publication No. 2011/016243

  The present invention has been made in view of the above-described problems and the like, and provides a power storage element in which a short circuit between electrodes is suppressed even when a current collecting base material is bent at an end of both a positive electrode and a negative electrode. As an issue.

In order to solve the above problems, a power storage device according to the present invention is:
An electrode body in which a plurality of sheet-shaped positive electrodes and a plurality of sheet-shaped negative electrodes are stacked so as to be alternately arranged in the thickness direction one by one as a rectangular electrode,
The electrode body includes a separator disposed between the positive electrode and the negative electrode, and is pressed by an external force,
The electrodes each include at least a current collecting base material and an active material layer, and form a current collecting tab in which a part of an end of the current collecting base material projects outward and is not covered with the active material layer and is exposed. And
In the electrode body, an outer portion of the current collecting tab is bundled with each other by each electrode,
Each of the current-collecting base materials extends to all ends of each of the electrodes, and is bent toward one side in the stacking direction at the ends,
At the ends of the positive electrode and the negative electrode adjacent to each other, the edge of each current-collecting base material protrudes outside the edge of each active material layer, and each direction in the stacking direction in which the current-collecting substrate is bent. Are the same as each other.

In the power storage device having the above-described configuration, the direction of the thickness direction in which the current collecting base material is bent while extending toward the edge of the electrode is the same at both ends of the positive electrode and the negative electrode adjacent to each other.
Accordingly, between the ends of the positive electrode and the negative electrode adjacent to each other, the current-collecting base material of one electrode arranged on the opposite side to the direction in which the current-collecting base material is bent approaches the current-collecting base material of the other electrode. Although being bent, the current collecting base material of the other electrode is bent in the same direction as the current collecting base material of the one electrode. Thereby, the current-collecting base materials of the electrodes are prevented from approaching each other, and the current-collecting base materials of the electrodes are prevented from coming into contact with each other.
Thus, in the above-described power storage element, a short circuit between the electrodes is suppressed despite the fact that the current collecting base material is bent at both ends of the positive electrode and the negative electrode.

  As one mode of the power storage device according to the present invention, a mode is adopted in which each electrode includes an active material layer disposed on each side of the current collecting base material.

  As another embodiment of the power storage element according to the present invention, at the ends of the positive electrode and the negative electrode alternately arranged in the laminating direction, the positive electrode current collector as the current collector is bent in the same direction, and In which the negative electrode current collecting base material is bent in the same direction as the positive electrode current collecting base material at the end.

  As another mode of the power storage device according to the present invention, a mode is adopted in which the thicknesses of the positive electrode and the negative electrode are constant.

  As another mode of the power storage element according to the present invention, in the stacked positive electrode and negative electrode, an area in which the area of the active material layer of the negative electrode is larger than the area of the active material layer of the positive electrode is adopted.

  The power storage device according to the present invention has an effect that a short circuit between the electrodes is suppressed, despite the fact that the current collecting base material is bent at both ends of the positive electrode and the negative electrode.

FIG. 4 is a cross-sectional view schematically illustrating an example of a II-II cross section of the electrode body in FIG. 3. FIG. 4 is a cross-sectional view schematically illustrating another example of the II-II cross section of the electrode body in FIG. 3. FIG. 4 is a schematic diagram schematically illustrating a state in which a flat electrode body is viewed from one surface side. FIG. 2 is a schematic diagram schematically illustrating a laminated structure of an electrode body. FIG. 2 is a schematic diagram schematically showing an internal structure of a nonaqueous electrolyte secondary battery (lithium ion secondary battery) as a storage element. FIG. 2 is a schematic diagram schematically illustrating a cross section of an example of an electrode body. The schematic diagram which decomposed | disassembled and showed a part of structure of an example of a wound-type electrode body typically. FIG. 10 is a schematic diagram schematically illustrating a cross section taken along line IV-IV of the electrode body illustrated in FIG. 9. The figure showing appearance of other examples of the nonaqueous electrolyte secondary battery (lithium ion secondary battery) as an electric storage element. FIG. 4 is a schematic diagram schematically illustrating a state before a plurality of power storage elements are pressed in the power storage device.

  Hereinafter, an embodiment of a power storage device according to the present invention will be described with reference to the drawings. Embodiments of the electric storage element include a primary battery, a secondary battery, and a capacitor. In this embodiment, a chargeable / dischargeable secondary battery is described as an example of a power storage element.

As shown in FIG. 1 and FIG.
A sheet-like positive electrode 10 and a negative electrode 20 are provided as electrodes;
The positive electrode 10 and the negative electrode 20 are stacked,
Each electrode includes at least a current collecting base material and an active material layer,
At least a part of each current-collecting base material extends to an end of each electrode, and is bent toward one side in the stacking direction at the end,
At the ends of the positive electrode 10 and the negative electrode 20 that are adjacent to each other, the respective directions of the lamination directions in which the current-collecting base material bends are the same.
Specifically, in the power storage element 1 of the present embodiment, at the ends of the positive electrode 10 and the negative electrode 20 alternately arranged in the stacking direction, the positive electrode current collector base 11 as the current collector is bent in the same direction, The negative electrode current collecting base material 21 as a material is bent in the same direction as the positive electrode current collecting base material 11 at the end.

The power storage element of the present embodiment is a non-aqueous electrolyte secondary battery. Specifically, as the power storage element 1 of the present embodiment, for example, a non-aqueous electrolyte secondary battery 1 (lithium ion secondary battery) shown in FIGS.
This type of storage element supplies electric energy. A single or a plurality of power storage elements are used. Specifically, the storage element is used alone when the required output and the required voltage are small. On the other hand, when at least one of the required output and the required voltage is large, the power storage element is used in a power storage device in combination with another power storage element. In a power storage device, a power storage element used for the power storage device supplies electric energy.

<First embodiment>
The power storage device 1 of the first embodiment includes an electrode body in which positive electrodes 10 and negative electrodes 20 as electrodes are alternately arranged in the stacking direction. Specifically, the power storage device 1 of the first embodiment includes an electrode body 2 in which a plurality of positive electrodes 10 and a plurality of negative electrodes 20 are stacked, as shown in FIGS. 1 and 2.
Further, the power storage device 1 of the first embodiment includes a case 40 that houses the electrode body 2 therein, for example, as illustrated in FIG.
Further, the electric storage device 1 of the first embodiment includes the electrolytic solution stored in the case 40.

The power storage device 1 of the first embodiment includes a plurality of sheet-shaped separators 3.
As shown in FIGS. 1 and 2, the separator 3 is disposed between the positive electrode 10 and the negative electrode 20. As shown in FIG. 1, the separators 3 can be arranged on the outermost sides in the stacking direction of the electrode bodies 2. On the other hand, as shown in FIG. 2, the separator 3 does not have to be disposed on the outermost side in the stacking direction of the electrode body 2.

The electrode body 2 is formed in a flat shape (plate shape).
The electrode body 2 includes a plurality of positive electrodes 10 and a plurality of negative electrodes 20, for example, as shown in FIGS. 4 and 5, and is formed by alternately stacking the positive electrodes 10 and the negative electrodes 20 in the thickness direction.
In addition, the electrode body 2 may be formed by, for example, laminating a band-shaped positive electrode 10 and a band-shaped negative electrode 20 and winding the same, as described later.

Specifically, the electrode body 2 includes a sheet-shaped positive electrode 10 and a sheet-shaped negative electrode 20 as electrodes, for example, as shown in FIGS. 1 and 2. At least one of the positive electrode 10 and the negative electrode 20 is formed in a rectangular shape.
Each electrode includes a sheet-shaped current collecting base material and an active material layer containing an active material. The active material layers are preferably disposed on both sides of the current collecting base material.
More specifically, as shown in FIGS. 1 and 2, for example, the positive electrode 10 includes a sheet-shaped positive electrode current collecting base material 11 and positive electrode active material containing a positive electrode active material and disposed on both sides of the positive electrode current collecting base material 11, respectively. And a material layer 12.
Similarly, for example, as shown in FIGS. 1 and 2, the negative electrode 20 includes a sheet-shaped negative electrode current-collecting base material 21 and a negative electrode active material that includes a negative electrode active material and is disposed on both sides of the negative electrode current-collecting substrate 21. And a material layer 22.
For example, in each of the rectangular electrodes, the current collecting base material bends at least at the ends along two sides, and the direction in which the current collecting base material bends at the bent end portion of the current collecting base material is the same.

Specifically, each of the positive electrode 10 and the negative electrode 20 as an electrode has, at at least a part of the end, a bent end 6 in which the current-collecting base material is bent by being cut in the thickness direction.
In the bent end portion 6, active material layers 12 and 22 are arranged on both sides of the current collecting base materials 11 and 21. In addition, the current collector bases 11 and 21 are bent toward one surface side of the electrodes (the positive electrode 10 and the negative electrode 20) while extending to the edge of the electrode.
Further, as shown in FIGS. 1 and 2, for example, the bent ends 6 of the positive electrode 10 and the negative electrode 20 are arranged so as to be adjacent to each other in the thickness direction (stacking direction).
Further, at the bent end portions 6 of the positive electrode 10 and the negative electrode 20 adjacent to each other, the thickness directions in which the current collecting base materials 11 and 21 are bent toward one surface side of the electrodes (the positive electrode 10 and the negative electrode 20) are the same. It is.

In power storage element 1 of the present embodiment, positive electrode 10 and negative electrode 20 each have bent end portions 6 formed by cutting in the thickness direction. Therefore, at each bent end, the current collecting bases 11 and 21 are bent toward one surface side of the electrodes (the positive electrode 10 and the negative electrode 20) while extending to the edge of the electrode.
However, the bent ends 6 of the positive electrode 10 and the negative electrode 20 are adjacent to each other, and the direction of the thickness direction in which the current collecting base material is bent toward one surface side of each electrode at each bent end 6 is the same. Direction.
Between the bent ends 6 adjacent to each other, the current-collecting base material (for example, the negative electrode 20) of one electrode (for example, the negative electrode 20) arranged on the opposite side to the direction in which the current-collecting substrate (for example, the positive electrode current-collecting substrate 11) bends Although the negative electrode current collector 21 is bent so as to approach the current collector of the other electrode (for example, the positive electrode current collector 11), the current collector of the other electrode (for example, the positive electrode current collector 11) is bent in the same direction as the current collecting base material of one electrode (for example, the negative electrode current collecting base material 21). Therefore, the current collecting bases 11 and 21 of each electrode are suppressed from approaching each other, and the contact between the current collecting bases (11 and 21) of the positive electrode 10 and the negative electrode 20 is suppressed.
As a result, in the power storage device 1 of the present embodiment, a short circuit between the positive electrode 10 and the negative electrode 20 is suppressed, despite the fact that the current collecting base material is bent at both ends of the positive electrode 10 and the negative electrode 20. I have. Specifically, although both the positive electrode 10 and the negative electrode 20 are provided with electrodes formed by cutting an electrode original plate (a positive electrode original plate and a negative electrode original plate) including at least a current collecting base material, And the short circuit between the negative electrodes 20 is suppressed.

As shown in FIGS. 1 and 2, for example, the positive electrode 10 includes a sheet-shaped positive electrode current collecting base material 11 and a positive electrode active material layer 12 containing a particulate positive electrode active material. The positive electrode active material layer 12 is disposed on both sides of the positive electrode current collector base material 11.
The shape of the positive electrode 10 is, for example, a rectangular sheet shape as shown in FIG.
The thickness of the positive electrode 10 is usually 35 to 250 μm. The thickness of the positive electrode current collector base material 11 is usually 5 to 50 μm, and the thickness of the positive electrode active material layer 12 is usually 15 to 100 μm.
The thickness of the positive electrode 10 is usually constant.

The negative electrode 20 includes a sheet-shaped negative electrode current collecting base material 21 and a negative electrode active material layer 22 disposed on both sides of the negative electrode current collecting base material 21 and containing a particulate negative electrode active material.
The shape of the negative electrode 20 is, for example, a rectangular sheet shape as shown in FIG.
The thickness of the negative electrode 20 is usually 35 to 250 μm. The thickness of the negative electrode current collecting base material 21 is usually 5 to 50 μm, and the thickness of the negative electrode active material layer 22 is usually 15 to 100 μm.
Usually, the thickness of the negative electrode 20 is constant.

In the electrode body 2, for example, as shown in FIGS. 1 and 2, the positive electrode 10 and the negative electrode 20 are interposed via the separator 3 so that the positive electrode active material layer 12 and the negative electrode active material layer 22 face each other in the thickness direction. Are superimposed.
In the electrode body 2, for example, as shown in FIG. 4, a plurality of positive electrodes 10 and a plurality of negative electrodes 20 are stacked in the thickness direction, and the positive electrodes 10 and the negative electrodes 20 are alternately arranged in the stacking direction. The positive electrode active material layer 12 of the positive electrode 10 and the negative electrode active material layer 22 of the negative electrode 20 face each other with the separator 3 interposed therebetween.

Each of the electrodes (the positive electrode 10 and the negative electrode 20) has a bent end 6 formed in at least a part of the end by being cut in the thickness direction.
The bent end portion 6 is such that an electrode plate including the current-collecting base material before cutting and the active material layers before cutting arranged on both sides of the current-collecting base material before cutting is cut in the thickness direction. Is formed by Details of the electrode base plate will be described later.

Since the bent end portion 6 is formed by cutting the electrode base plate in the thickness direction, the bent end portion 6 extends toward the edge of the electrode while the current-collecting base material extends toward one of the active material layers of the electrode. (To one side in the thickness direction of the electrode). For example, as shown in FIGS. 1 and 2, at the bent end portion 6, the current collecting base material extends to the edge of the electrode. At the bent end portions 6, the active material layers are arranged on both sides of the current collecting base material.
For example, the bent end portion 6 is formed so that the current collecting base material approaches one surface side of the electrode as it approaches the edge of the electrode.

  The bent end portion 6 is a portion at the end of each electrode from a portion where the current collecting base material extending toward the edge of the electrode starts to approach one surface side of the electrode to the edge of the electrode.

  The bent end portion 6 is formed by cutting the original electrode plate by applying a cutting force from at least one direction side in the thickness direction to the other direction side.

In the electrode body 2, the bent ends 6 of the positive electrode 10 and the negative electrode 20 are arranged via the separator 3 so as to be adjacent to each other in the laminating direction (thickness direction).
The term “adjacent” to the bent ends 6 of the electrodes means that at least a part of one bent end 6 and at least a part of the other bent end 6 are mutually adjacent as shown in FIGS. It means facing each other. That is, when each bent end 6 is viewed from one side in the thickness direction (lamination direction) of the electrode to the other side, at least a part of one bent end 6 is at least a part of the other bent end 6. Means overlapping.

  In the electrode body 2, at the bent end portions 6 of the positive electrode 10 and the negative electrode 20 adjacent to each other, the thickness direction in which the current collecting base material extends toward the edge of the positive electrode 10 or the negative electrode 20 and bends toward one active material layer side Are the same as each other. That is, the direction in which the positive electrode current collecting base material 11 bends at the bent end portion 6 of the positive electrode 10, and the direction in which the negative electrode current collecting base material 21 bends at the bent end portion 6 of the negative electrode 20 adjacent to the bent end portion 6 of the positive electrode 10. However, both are in the same direction.

Since the electrode body 2 is configured as described above, as described above, the current collecting base material (for example, 21) is disposed on the opposite side to the bending direction between the adjacent bent ends 6, 6. The current collecting base material (for example, the positive current collecting base material 11) of the electrode (for example, the positive electrode 10) is bent so as to approach the current collecting base material (for example, the negative current collecting base material 21) of the other electrode. The current collecting base material of the electrode (for example, the negative electrode current collecting base material 21) is bent in the same direction as the current collecting base material of one of the electrodes (for example, the positive electrode current collecting base material 11). Therefore, the current collecting bases 11 and 21 of each electrode are suppressed from approaching each other, and the contact between the current collecting bases (11 and 21) of the positive electrode 10 and the negative electrode 20 is suppressed.
Thereby, in the above-mentioned electrode body 2, both the positive electrode 10 and the negative electrode 20 are provided with an electrode formed by cutting an electrode original plate (a positive electrode original plate, a negative electrode original plate) containing at least a current collecting base material. The short circuit between the negative electrode 10 and the negative electrode 20 is suppressed.

  In the electrode body 2, as shown in FIGS. 1 and 2, the positive electrodes 10 and the negative electrodes 20 are alternately arranged in the laminating direction. More specifically, the bent ends 6 of the positive electrode 10 are arranged in the laminating direction, and the bent ends 6 of the negative electrode 20 are arranged in the laminating direction. At the bent ends 6 of the plurality of positive electrodes 10 arranged in the stacking direction, the direction of bending of each current-collecting base material is the same. In addition, at the bent ends 6 of the plurality of negative electrodes 20 arranged in the stacking direction, the bending directions of the respective current collecting base materials are the same.

  As shown in FIG. 1, for example, the bent end portion 6 is formed such that the edge of the current collecting base material and the edge of each active material layer are flush. Alternatively, the bent end 6 may be formed such that the edge of the current collecting base material protrudes outside the edge of the active material layer, as shown in FIG. 2, for example.

The bent end 6 is formed on at least a part of the end of each electrode (the positive electrode 10 and the negative electrode 20). Preferably, at least one of the electrodes is formed in a rectangular shape, and a bent end 6 is formed at an end along at least two sides of the rectangular electrode.
Specifically, the bent end portion 6 is formed, for example, along three sides of the rectangular electrode. The current collecting tab described later is an end on which the bent end 6 is not formed, and may be arranged on a part of an end along the remaining one side of the electrode.
The bent end 6 may be formed on all the ends of each electrode (the positive electrode 10 and the negative electrode 20). Specifically, the bent end portions 6 may be formed on all the end portions, for example, by punching an electrode plate. By punching the electrode base plate, a current collecting tab projecting outside the separator 3 can be formed.
When the electrode body 2 is of a wound type described later, the bent end portion 6 is usually formed along two opposing sides of a rectangular electrode. In this case, in the electrode body 2, the bent end portions 6 are arranged on both sides of the winding shaft along the winding direction.

  Note that the current collecting bases 11 and 21 at the bent end portions 6 of the respective electrodes are usually bent in the same direction. For example, at the bent end portions 6 formed along at least two sides of the rectangular electrode, the current collecting base materials 11 and 21 are bent in the same direction.

  At the bent end portion 6, the bend width (the length of A shown in FIG. 1) of the current collector bases 11 and 21 is usually more than 0 μm and 100 μm or less. The bending width is the maximum width (length in the thickness direction) of the current collecting base material at the bent end portion 6.

In the electrode body 2, in the stacked positive electrode 10 and negative electrode 20, the area of the negative electrode active material layer 22 is larger than the area of the positive electrode active material layer 12.
That is, in the electrode body 2, when viewed from one side in the stacking direction, for example, the area of the negative electrode active material layer 22 is larger than the area of the positive electrode active material layer 12. Moreover, the positive electrode active material layer 12 is disposed inside the negative electrode active material layer 22.
With such a configuration, Li ions that have moved from the positive electrode active material layer 12 to the negative electrode 20 during charging can be reliably absorbed in the negative electrode active material layer 22.

  Each electrode may have a non-covered portion on at least a part of an end, in which the current collecting base is exposed without being covered with the active material layer. An example of the non-covered portion is a current collecting tab in which a part of the current collecting base protrudes outward so as to be an electric path to the outside of the battery.

The positive electrode current collector base material 11 is usually formed in a rectangular sheet shape. A part of the end portion of the positive electrode current collecting base material 11 may protrude outward to form a current collecting tab 11a.
The thickness of the positive electrode current collector 11 is not particularly limited, but is usually 1 to 500 μm.

Examples of the material of the positive electrode current collecting base material 11 include metals such as aluminum, titanium, stainless steel, and nickel.
Examples of the material of the positive electrode current collecting base material 11 include, in addition to metal, for example, calcined carbon, a conductive polymer, and the like.
Examples of the positive electrode current collecting base material 11 include a metal foil.

  The shape of the positive electrode active material layer 12 is, for example, rectangular when viewed from one surface side.

The positive electrode active material contains a metal compound that can contribute to an electrode reaction of a charging reaction and a discharging reaction in the positive electrode 10.
The positive electrode active material is usually formed in a particle shape.

The metal compound contained in the positive electrode active material is not particularly limited, and for example, lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium spinel manganate (LiMn ₂ O ₄ ), and lithium cobalt oxide (LiCoO ₂ ) And the like.
In addition, examples of such a metal compound include olivine-type lithium metal phosphate such as lithium iron phosphate.

  The positive electrode active material layer 12 contains a conductive agent, a binder, a thickener, a filler, and the like as necessary as constituent components.

The conductive agent is not particularly limited and includes, for example, natural graphite (flaky graphite, flaky graphite, earthy graphite, etc.), artificial graphite, carbon black, acetylene black, ketjen black, carbon whiskers, carbon fiber, metal (copper , Nickel, aluminum, silver, gold, etc.) powder, metal fibers, conductive ceramics and the like.
As the conductive agent, for example, the above-mentioned one kind alone or a mixture of two or more kinds is used.

The binder is not particularly limited. For example, thermoplastic resins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, and polypropylene; ethylene-propylene-diene terpolymer (EPDM); EPDM, styrene butadiene rubber (SBR), fluorine rubber, and the like are included.
As the binder, for example, one kind of the above-described one kind alone or a mixture of two or more kinds thereof is employed.

The thickener is not particularly limited, and includes, for example, polysaccharides such as carboxymethylcellulose and methylcellulose.
As the thickener, for example, one of the above-mentioned one kind alone or a mixture of two or more kinds is used.

  The filler is not particularly limited, and includes, for example, olefin polymers such as polypropylene and polyethylene, amorphous silica, alumina, zeolite, and glass.

The negative electrode current collecting base material 21 is usually formed in a rectangular sheet shape. A part of the end portion of the negative electrode current collector base 21 may protrude outward to form a current collection tab 21a.
The thickness of the negative electrode current collector substrate 21 is not particularly limited, but is usually 1 to 500 μm, and preferably 5 to 50 μm.

Examples of the material of the negative electrode current collecting base material 21 include metals such as copper, nickel, iron, stainless steel, titanium, and aluminum.
Examples of the material of the negative electrode current collecting base material 21 include fired carbon, a conductive polymer, and conductive glass in addition to metal.
Examples of the negative electrode current collecting base material 21 include metal foils of the above metals.

  The shape of the negative electrode active material layer 22 is, for example, a rectangular shape when viewed from one surface side.

The negative electrode active material is a material that can contribute to an electrode reaction of a charge reaction and a discharge reaction in the negative electrode 20.
As the negative electrode active material, for example, a carbonaceous material, lithium metal, an alloy capable of occluding and releasing lithium ions (such as a lithium alloy), and a general formula MOz (M is selected from W, Mo, Si, Cu, and Sn) A metal oxide, a lithium metal oxide (such as Li ₄ Ti ₅ O ₁₂ ) represented by at least one element, and z represents a numerical value in a range of 0 <z ≦ 2, and a polyphosphate compound At least one of them.

Examples of the carbonaceous material include at least one of graphite (graphite) and amorphous carbon.
Examples of the amorphous carbon include non-graphitizable carbon (hard carbon) and easily graphitizable carbon (soft carbon).

  Examples of the alloy capable of inserting and extracting lithium ions include, for example, at least one lithium alloy of a lithium-aluminum alloy, a lithium-lead alloy, a lithium-tin alloy, a lithium-aluminum-tin alloy, and a lithium-gallium alloy Or a wood alloy.

  Like the positive electrode active material layer 12, the negative electrode active material layer 22 contains the above-described binder, thickener, filler, and the like as necessary as constituent components.

The separator 3 prevents a short circuit between the electrodes while ensuring a charge / discharge reaction between the electrodes.
The separator 3 is disposed between the positive electrode active material layer 12 of the positive electrode 10 and the negative electrode active material layer 22 of the negative electrode 20.

  Examples of the separator 3 include a separator made of a porous film or a nonwoven fabric. The separator 3 is made of, for example, a single material such as a porous film or a nonwoven fabric, or a combination thereof.

  Examples of the material of the separator 3 include at least one of a polyolefin resin such as polyethylene and polypropylene, a polyester resin such as polyethylene terephthalate and polybutylene terephthalate, and a fluorine resin.

  The electrolyte is accommodated in the case 40. At least a part of the electrolyte is impregnated in the electrode body 2 accommodated in the case 40.

The electrolyte typically contains a non-aqueous solvent and an electrolyte salt.
The electrolyte usually contains an electrolyte salt at a concentration of 0.5 to 2.0 mol / L.

As the non-aqueous solvent, a solvent generally used in a power storage element or the like is employed.
Specifically, examples of the non-aqueous solvent include cyclic carbonates, lactones, chain carbonates, chain esters, ethers, nitriles and the like.
Examples of the cyclic carbonates include propylene carbonate, ethylene carbonate, butylene carbonate, chloroethylene carbonate and the like.
Examples of the lactones include γ-butyrolactone, γ-valerolactone and the like.
Examples of the chain carbonates include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and the like.
Examples of the chain esters include methyl formate, methyl acetate, methyl butyrate and the like.
Examples of the ethers include 1,3-dioxane, 1,4-dioxane, 1,2-dimethoxyethane, 1,4-dibutoxyethane, and methyldiglyme.
Examples of the nitriles include acetonitrile, benzonitrile and the like.
Further, examples of the non-aqueous solvent include tetrahydrofuran or a derivative thereof, dioxolane or a derivative thereof, ethylene sulfide, sulfolane, sultone or a derivative thereof, and the like.
As the non-aqueous solvent, the above-mentioned single substance or a mixture of two or more of the above-mentioned substances is adopted, but it is not limited to these.

As the electrolyte salt, for example, LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN (SO ₂ CF _{3) ) (SO 2 C 4 F 9} ), LiSCN, LiBr, LiI, include lithium salts such as _{Li 2 SO 4, Li 2 B} 10 Cl 10.
As the electrolyte salt, the above-described single substance, a mixture of two or more kinds, and the like are employed, but are not limited thereto.

  As shown in FIGS. 5 and 6, the nonaqueous electrolyte secondary battery 1 further includes a case 40 that houses the electrode body 2 therein, and a terminal that serves as an electrical path between the battery and the outside during charging and discharging. And As the terminal, for example, a flat-plate terminal 51 is used.

As shown in FIG. 5, the case 40 has a pair of case pieces 41.
Each case piece 41 has a housing portion 41a that opens in one direction and houses the electrode body 2, and a flange portion 41b that extends outward from an opening edge of the housing portion 41a.
The case 40 is configured such that the surfaces of the flange portions 41b of the case pieces 41 are joined to each other while the openings of the accommodation portions 41a of the case pieces 41 face each other, so that the electrode body is formed in the space inside the two accommodation portions 41a after the joining. 2 and an electrolytic solution.
Each case piece 41 is formed of, for example, a laminate material in which an aluminum foil and a resin film are laminated.

  The electrode body 2 as described above is housed in the case 40, for example. The electrode body 2 is formed by laminating a plurality of positive electrodes 10 and a plurality of negative electrodes 20 one by one so as to be alternately arranged in the thickness direction.

  The electrode body 2 is surrounded by the case 40 from the outside and accommodated in the case 40 by the pair of case pieces 41 being joined to each other as described above.

The plate terminals 51 include a plate terminal 51a for a positive electrode and a plate terminal 51b for a negative electrode.
The flat plate terminal 51a for the positive electrode is connected to the current collecting tab 11a of each positive electrode current collecting base material 11 in the electrode body 2 by, for example, a welding process. The outer portion of the current collecting tab 11a is connected to the flat terminal 51a after being overlapped with each other.
Similarly, the negative electrode plate terminal 51b is connected to the current collecting tab 21a of each negative electrode current collecting base material 21 in the electrode body 2 by, for example, a welding process. The outer portion of the current collecting tab 21a is overlapped with each other and connected to the flat terminal 51b.
Part of the flat terminal 51 is disposed outside the case 40 so as to be electrically connected to another power storage element or an external device.

The electrode body 2 can be compressed by an external force. As described above, the electrode body 2 is suppressed from being short-circuited between the electrodes even when the positive electrode 10 and the negative electrode 20 are close to each other by being pressed.
For example, the case 40 having the same internal space width as the thickness of the electrode body 2 is accommodated in the case 40 that is not deformed, and then the electrolytic solution is injected into the case 40. Impregnated. As a result, the electrode body 2 swells, and the electrode body 2 is pressed by a force repelling the swelling force. In addition, for example, when the electric storage element 1 is used, the electrode body 2 swells due to charging, and the electrode body 2 is similarly pressed.

  In addition, for example, a plurality of power storage elements 1 that are electrically connected in series and stacked together constitute a power storage unit 105, and the power storage unit 105 is pressed from outside by a fixing member 110. As a result, the electrode body 2 is pressed by an external force.

  Specifically, power storage device 100 includes a power storage unit 105 including a plurality of power storage elements 1 that are electrically connected in series and stacked, a fixing member 110 that internally fixes power storage unit 105 while compressing power storage unit 105, and a power storage device 100. An input / output member 103 for inputting and outputting electricity, and insulating covers 108 and 109 for insulating the storage element 1 and the fixing member 110 are provided.

The power storage unit 105 is configured by a plurality of power storage elements 1 formed by connecting a positive terminal and a negative terminal of each power storage element 1 directly or indirectly by a bus bar.
As shown in FIG. 10, the fixing member 110 includes a cylindrical body 111 having one opening, and a lid 112 for closing the opening of the cylindrical body 111. The cylinder 111 and the lid 112 are each formed of, for example, an aluminum alloy or the like. The cylindrical body 111 and the lid body 112 are fitted together by, for example, a winding method. Thereby, the plurality of power storage elements 1 are pressed by an external force.
The insulating covers 108 and 109 are formed of an insulating material such as a resin. Two openings are formed in one insulating cover 108 so that a part of the input / output member 103 passes therethrough.
Each input / output member 103 is configured to input and output electricity from a power storage unit 105 including a plurality of power storage elements 1 electrically connected in series. Each input / output member 103 is attached to power storage unit 105 so as to protrude to the side of power storage unit 105.

  The power storage element 1 of the first embodiment includes, for example, the electrode body 2 in which the plurality of positive electrodes 10 and the plurality of negative electrodes 20 are alternately stacked a plurality of times in the thickness direction as described above. An energy storage device 1 according to an embodiment of the present invention has an electrode body 2 (hereinafter referred to as a wound-type electrode body) formed by laminating a single strip-shaped positive electrode 10 and a single strip-shaped negative electrode 20 and further winding the same. (Hereinafter, also referred to as a power storage element of the second embodiment).

<Second embodiment>
The power storage device 1 of the second embodiment includes a sheet-shaped positive electrode 10 and a negative electrode 20 as electrodes, similarly to the power storage device 1 of the first embodiment.
In the energy storage device 1 of the second embodiment, as shown in FIGS. 7 to 9, one positive electrode 10 and one negative electrode 20 are stacked and further wound to form an electrode body 2 (winding type). Electrode body) is formed.

In the wound electrode body 2, at least a part of the end has a structure as shown in FIG. 1 or FIG.
As shown in FIG. 7, for example, the wound electrode body 2 has a flat rectangular plate shape in a wound state, and the wound electrode body 2 has bent ends along two opposing sides. A part 6 is provided. Specifically, bent ends 6 are formed at both ends in the longitudinal direction of the strip-shaped electrode, and the bent ends 6 arranged on both ends in the longitudinal direction of the strip-shaped positive electrode 10 and the bent ends 6 of the strip-shaped negative electrode 20 are formed. The bent ends 6 arranged at both ends in the direction are alternately arranged in the laminating direction.
Similar to the power storage element 1 of the first embodiment, the power storage element 1 of the second embodiment suppresses a short circuit between the electrodes even though the current collecting base material is bent at the end of the electrode. . That is, in the power storage device 1 of the second embodiment, the short-circuit between the electrodes is suppressed despite the fact that the current-collecting base material has the bent electrodes due to the cutting.
The power storage device 1 according to the second embodiment has the same configuration as the configuration according to the first embodiment unless otherwise specified.

  The power storage element 1 (the power storage element 1 including the wound electrode body 2) of the second embodiment accommodates the wound electrode body 2 and the electrode body 2 as shown in FIGS. The case 40 includes a case 40 and external terminals 55 that are arranged outside the case 40 and are electrically connected to the electrode body 2. In addition, the power storage element 1 includes a current collector 5 that conducts the electrode body 2 and the external terminal 55, in addition to the electrode body 2, the case 40, and the external terminal 55.

As shown in FIG. 7, the positive electrode 10 of the spirally wound electrode body 2 has an uncovered portion that is not covered with the positive electrode active material layer 12 on one edge in the width direction, which is the short direction of the belt shape. 10a (a portion where the positive electrode current collecting base material 11 is exposed).
The negative electrode 20 of the spirally wound electrode body 2 is covered with a negative electrode active material layer 22 at the other end (the side opposite to the non-covered portion of the positive electrode 10) in the width direction, which is the short direction of the belt shape. There is no uncovered portion 20a (the portion where the negative electrode current collecting base material 21 is exposed). The width of the negative electrode active material layer 22 is larger than the width of the positive electrode active material layer 12.
In the wound electrode body 2, as shown in FIG. 7, the positive electrode 10 and the negative electrode 20 are wound while being insulated by the separator 3. In the electrode body 2, the positive electrode 10 and the negative electrode 20 are insulated from each other by the separator 3, which is an insulating member. Separator 3 holds the electrolytic solution in case 40. Thereby, at the time of charging / discharging of the storage element 1, lithium ions move between the positive electrode 10 and the negative electrode 20, which are alternately stacked with the separator 3 interposed therebetween.

  The width of the separator 3 (the dimension in the width direction of the strip) is slightly larger than the width of the negative electrode active material layer 22. The positive electrode 10 and the negative electrode 20 are superimposed on each other while being displaced in the width direction, and the separator 3 is disposed between the positive electrode 10 and the negative electrode 20. The uncoated portion 10a of the positive electrode 10 and the uncoated portion 20a of the negative electrode 20 do not overlap. That is, the uncovered portion 10a of the positive electrode 10 protrudes in the width direction from the region where the positive electrode 10 and the negative electrode 20 overlap, and the uncovered portion 20a of the negative electrode 20 extends in the width direction from the region where the positive electrode 10 and the negative electrode 20 overlap. (The direction opposite to the direction in which the uncovered portion of the positive electrode 10 protrudes). The electrode body 2 is formed by winding the stacked positive electrode 10, negative electrode 20, and separator 3.

The uncoated laminated portion 26 of the electrode body 2 is formed by the portion where the uncoated portion 10a of the positive electrode 10 is laminated, and the uncoated laminated portion 26 of the electrode body 2 is formed by the portion where the uncoated portion 20a of the negative electrode 20 is laminated. Are formed.
The uncoated laminated portion 26 is a portion that is electrically connected to the current collector 5. When viewed from the winding center direction of the wound positive electrode 10, the negative electrode 20, and the separator 3, the uncoated laminated portion 26 has, for example, two portions (a non-divided non-split portion) sandwiching the hollow portion 9 (see FIG. 8). It is divided into coating laminated portions 26a, 26a).
The uncoated laminated portion 26 is provided at each pole of the electrode body 2. That is, the uncoated laminated portion 26 in which only the uncoated portion 10a of the positive electrode 10 is laminated constitutes the uncoated laminated portion of the positive electrode 10 in the electrode body 2, and the uncoated laminated portion in which only the uncoated portion 20a of the negative electrode 20 is laminated. The part 26 constitutes the uncoated laminated part of the negative electrode 20 in the electrode body 2.

The case 40 includes a case body 45 having an opening, and a cover plate 46 that closes (closes) the opening of the case body 45. The case 40 accommodates an electrolytic solution in an internal space in addition to the electrode body 2 and the current collector 5. The case 40 is formed of a metal having resistance to the electrolyte. The case 40 is formed of, for example, aluminum or an aluminum-based metal material such as an aluminum alloy. The case 40 may be formed of a metal material such as stainless steel and nickel, or a composite material obtained by bonding a resin such as nylon to aluminum.
The case 40 is formed by joining the peripheral edge of the opening of the case body 45 and the peripheral edge of the cover plate 46 in a state of being overlapped. The case 40 has an internal space defined by the case body 45 and the cover plate 46. The peripheral edge of the opening of the case body 45 and the peripheral edge of the lid plate 46 are joined by, for example, welding.

The cover plate 46 is a plate-like member that closes the opening of the case body 45. Specifically, the peripheral edge of the lid plate 46 is overlapped with the peripheral edge of the opening of the case main body 45 so that the lid plate 46 closes the opening of the case main body 45, and the opening peripheral edge and the lid plate 46 are overlapped. The case 40 is formed by welding the boundary between the cover plate 46 and the case body 45.
The cover plate 46 has a contour shape corresponding to the peripheral edge of the opening of the case body 45. That is, the cover plate 46 is a rectangular plate material. The four corners of the cover plate 46 are arc-shaped.

The cover plate 46 has a gas discharge valve 46a capable of discharging the gas inside the case 40 to the outside. The gas discharge valve 46a is configured to discharge gas from inside the case 40 to the outside when the internal pressure of the case 40 rises to a predetermined pressure. The gas discharge valve 46a is provided at the center of the cover plate 46.
The cover plate 46 is provided with a liquid injection hole for injecting the electrolytic solution. The liquid injection hole penetrates the cover plate 46 in the thickness direction.
The cover plate 46 includes a liquid injection stopper 46b that seals (closes) the liquid injection hole. The liquid injection stopper 46b is fixed to the case 40 (the cover plate 46) by welding.

The external terminal 55 is a portion that is electrically connected to an external terminal of another power storage element, an external device, or the like. The external terminal 55 is formed of a conductive member. For example, the external terminal 55 is formed of a metal material having high weldability, 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 55 has a surface 56 to which a bus bar or the like can be welded. Such a surface 56 is a plane.

The current collector 5 is arranged in the case 40 and is directly or indirectly connected to the electrode body 2 so as to be able to conduct electricity. The current collector 5 is electrically connected to the electrode body 2 via a clip member. That is, the electric storage element 1 includes a clip member that connects the electrode body 2 and the current collector 5 so as to be able to conduct electricity.
The current collector 5 is formed of a conductive member. The current collector 5 is arranged along the inner surface of the case 40.
Current collector 5 is connected to positive electrode 10 and negative electrode 20 of power storage device 1, respectively. In the power storage device 1 of the present embodiment, the current collector 5 is arranged in the case 40 so as to be connected to the uncoated laminated portion 26 of the positive electrode 10 of the electrode body 2 and the uncoated laminated portion 26 of the negative electrode 20, respectively. Have been.
The current collector 5 connected to the positive electrode 10 and the current collector 5 connected to the negative electrode 20 are formed of different materials. Specifically, the current collector 5 connected to the positive electrode 10 is formed of, for example, aluminum or an aluminum alloy, and the current collector 5 connected to the negative electrode 20 is formed of, for example, copper or a copper alloy.

  The electric storage element 1 of the present embodiment includes an insulating member 8 that insulates the electrode body 2 from the case 40. The insulating member 8 is disposed, for example, between the case 40 (specifically, the case body 45) and the electrode body 2. The insulating member 8 is formed of a sheet-like member having an insulating property. The insulating member 8 is formed of, for example, a resin such as polypropylene or polyphenylene sulfide.

  Next, a method of manufacturing the non-aqueous electrolyte secondary battery 1 (lithium ion secondary battery) as the above-described storage element 1 will be described.

The non-aqueous electrolyte secondary battery 1 is manufactured by a general method.
For example, the non-aqueous electrolyte secondary battery 1
An electrode original plate manufacturing step of manufacturing an electrode original plate in which the pre-cut active material layers are respectively arranged on both sides of the sheet-shaped pre-cut current collecting base material,
A cutting step of forming a positive electrode 10 and a negative electrode 20 as electrodes by cutting the electrode base plate in the thickness direction;
An electrode body manufacturing step of manufacturing the electrode body 2 by laminating the positive electrode 10 and the negative electrode 20 manufactured by cutting and the separator 3 in the thickness direction;
An accommodating step of accommodating the electrode body 2 and the electrolytic solution in the case 40 is performed.

  In the electrode base plate manufacturing step, a positive electrode base plate and a negative electrode base plate as electrode base plates are respectively manufactured.

In the production of the positive electrode plate, for example, the above-mentioned particulate positive electrode active material, conductive agent, binder, and thickener are mixed with an organic solvent such as N-methyl-2-pyrrolidone (NMP), Prepare a positive electrode mixture. Next, the positive electrode mixture is applied to both sides of the sheet-shaped positive electrode current collector before cutting. Subsequently, the organic solvent is volatilized from the positive electrode mixture by drying to prepare a positive electrode original plate in which the positive electrode active material layers 12 are arranged on both sides of the positive electrode current collector before cutting.
As the pre-cut positive electrode current collecting base material, the same material as the above-described positive electrode current collecting base material 11 is employed.

  Examples of a method of mixing a positive electrode active material, a conductive agent, a binder, a thickener, and the like in the preparation of a positive electrode plate include powders such as a V-type mixer, an S-type mixer, a grinder, a ball mill, and a planetary ball mill. A method of mixing using a body mixer is employed.

  The method of applying the positive electrode mixture to the positive electrode base material for preparing the positive electrode base plate is not particularly limited. For example, roller coating such as an applicator roll, screen coating, blade coating, spin coating, per coating, or the like is employed. Is done.

The negative electrode original plate is produced, for example, in the same manner as the positive electrode original plate.
Specifically, the negative electrode plate is produced, for example, by the same method as the above-described method for producing a positive electrode plate, except that a particulate negative electrode active material is used instead of the particulate positive electrode active material.
That is, in the preparation of the negative electrode original plate, for example, after preparing the negative electrode mixture by mixing the above-mentioned particulate negative electrode active material, binder, and thickener, and an organic solvent, the negative electrode mixture is sheeted It is applied to both sides of the negative electrode current collector before cutting. Next, the organic solvent is volatilized from the negative electrode mixture by drying. Then, an original negative electrode plate in which the negative electrode active material layers are arranged on both sides of the negative electrode current collecting base material before cutting is produced.
In addition, as the negative electrode current collecting base material before cutting, the same material as the above-described negative electrode current collecting base material 21 is employed.

In the cutting step, the positive electrode plate and the negative electrode plate are cut by a general method.
As a cutting method, for example, a method of cutting an original plate by a Thomson blade attached to a Thomson punching machine can be adopted. In the cutting, a gang system, a shear system, a razor system, a score system, or the like can be employed.

  By the cutting in the cutting step, the bent ends 6 are formed on the electrodes as described above. In cutting, a cutting force is applied to at least one direction in the thickness direction to both the positive electrode original plate and the negative electrode original plate. Therefore, by the cutting in the cutting step, the current collecting base material is bent to one side in the thickness direction at the bent end portion 6.

In the electrode body manufacturing step, for example, the plate-like electrode body 2 shown in FIGS. 3 to 5 is manufactured.
The electrode body 2 is produced, for example, by laminating a sheet-like positive electrode 10, a sheet-like separator 3, a sheet-like negative electrode 20, and a sheet-like separator 3 in this order in the thickness direction. At this time, the bent end portion 6 of the positive electrode 10 and the bent end portion 6 of the negative electrode 20 are at least adjacent to each other, and the orientation of the positive electrode current collecting base material 11 of the adjacent bent end portion 6 and the negative electrode current collecting substrate The positive electrode 10 and the negative electrode 20 are stacked so that the direction of 21 is the same. Also, the plurality of positive electrodes 10 are arranged in the stacking direction such that the bending direction of the current collecting base material at the bent end of the positive electrode 10 is the same direction, and the bending direction of the current collecting base material at the bent end of the negative electrode 20. Are arranged in the laminating direction such that are in the same direction. Further, the positive electrode 10, the separator 3, and the negative electrode 20 can be similarly stacked. When the electrode body 2 is formed by alternately laminating the plurality of positive electrodes 10 and the plurality of negative electrodes 20 one by one, for example, each positive electrode 10 and each negative electrode 20 are electrically connected in parallel.
In the electrode body manufacturing step, for example, the wound electrode body 2 shown in FIG. 7 can be manufactured.
In the production of the wound electrode body 2, for example, a laminate is prepared by laminating the strip-shaped positive electrode 10, the strip-shaped separator 3, the strip-shaped negative electrode 20, and the strip-shaped separator 3 in the thickness direction in this order. . At this time, the bent end portion 6 of the positive electrode 10 and the bent end portion of the negative electrode 20 are at least adjacent to each other, and the bending directions of the current collecting base material at each bent end portion are the same as each other. The positive electrode 10 and the negative electrode 20 are stacked. Further, the laminate is wound around an axis extending in the width direction of the laminate as a winding axis. Thus, the wound electrode body 2 is manufactured.

In the accommodation step, the produced electrode body 2 and the electrolytic solution are accommodated in the case 40. In addition, the flat terminal 51 is connected to the electrode body 2 by welding the outer portion of the current collecting tab 11a of each electrode to the flat terminal 51.
Specifically, the electrode body 2 is arranged in the case 40 by joining the flange portions 41b of the case pieces 41 described above to each other. At this time, the electrolyte solution prepared in advance is accommodated in the case 40. At this time, the flat plate terminal 51 for the positive electrode and the current collecting tab 11a of the bundled positive electrode 10 are connected, and the flat plate terminal 51 for the negative electrode and the current collecting tab 21a of the bundled negative electrode 20 are connected. At this time, a part of the flat plate terminal 51 for the positive electrode and a part of the flat plate terminal 51 for the negative electrode are respectively disposed outside the case 40.
In the housing step, the electrode body 2 can be pressed by an external force. Specifically, the electrode body 2 can be compressed by arranging the electrode body 2 in the rigid case 40 and fixing the electrode body 2 in the case 40 in a state where the electrode body 2 is compressed. Further, by disposing the electrode body 2 in the relatively flexible case 40, and housing the electrode body 2 in the case 40, and decompressing the inside of the case, the electrode body 2 can be pressed at atmospheric pressure.

  On the other hand, when manufacturing the wound electrode body 2, in the housing step, for example, first, the positive electrode 10, the separator 3, the negative electrode 20, and the separator 3 are stacked in this order, and then wound, and the electrode body is wound. Form 2 Subsequently, the electrode body 2 is put in the case body 45. Thereafter, the current collector 5 is connected to each of the positive electrode 10 and the negative electrode 20. Further, the case body 45 is covered with the cover plate 46 to which the external terminals 55 are attached, and the current collector 5 and the external terminals 55 are connected. In this state, the case body 45 and the cover plate 46 are welded. Inject the electrolyte through the inlet. Finally, the injection port is closed with the injection stopper 46b.

  As described above, the nonaqueous electrolyte secondary battery 1 as a power storage element can be manufactured.

  In addition, the electric storage element of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the spirit of the present invention. For example, the configuration of another embodiment can be added to the configuration of one embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Further, a part of the configuration of an embodiment can be deleted.

  Further, in the above-described embodiment, the case where the power storage element is used as a chargeable / dischargeable non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) has been described. However, the type and size (capacity) of the power storage element are arbitrary. It is. Further, in the above embodiment, a lithium ion secondary battery has been described as an example of a power storage element, but the present invention is not limited to this. For example, the present invention can be applied to various secondary batteries, primary batteries, and power storage elements of capacitors such as electric double layer capacitors.

The power storage element (for example, a battery) of the above embodiment may be used for a power storage device (a battery module when the power storage element is a battery). The power storage device (power storage module) includes at least two power storage elements 1 and a bus bar member that electrically connects the two (different) power storage elements 1 to each other. In this case, at least one of the above-described power storage elements 1 may be applied to power storage element 1.
In addition, after the electric storage element 1 is manufactured, the electrode body 2 of the first embodiment can be pressed by an external force. Specifically, as shown in FIG. 10, power storage unit 105 including a plurality of power storage elements 1 is arranged in cylinder 111, and cylinder 111 and lid 112 are fitted together by, for example, a winding method. I do. Thereby, the electrode body 2 can be pressed.

1: Storage element (lithium ion secondary battery),
2: electrode body,
3: separator,
5: current collector,
6: bent end,
10: positive electrode, 11: positive electrode current collector, 12: positive electrode active material layer,
20: negative electrode, 21: negative electrode current collector, 22: negative electrode active material layer,
40: Case,
41: case piece, 41a: accommodation part, 41b: flange part,
45: case body, 46: lid plate,
51: Flat terminal, 51a: Flat terminal for positive electrode, 51b: Flat terminal for negative electrode,
55: external terminal,
100: power storage device (power storage module),
103: input / output member, 105: power storage unit,
108, 109: insulating cover,
110: fixing member, 111: cylinder, 112: lid.

Claims (5)

An electrode body in which a plurality of sheet-shaped positive electrodes and a plurality of sheet-shaped negative electrodes are stacked so as to be alternately arranged in the thickness direction one by one as a rectangular electrode,
The electrode body includes a separator disposed between the positive electrode and the negative electrode, and is pressed by an external force,
The electrodes each include at least a current collecting base material and an active material layer, and form a current collecting tab in which a part of an end of the current collecting base material projects outward and is not covered with the active material layer and is exposed. And
In the electrode body, an outer portion of the current collecting tab is bundled with each other by each electrode,
Each of the current-collecting base materials extends to all ends of each of the electrodes, and is bent toward one side in the stacking direction at the ends,
At the ends of the positive electrode and the negative electrode adjacent to each other, the edge of each current-collecting base material protrudes outside the edge of each active material layer, and each direction in the stacking direction in which the current-collecting substrate is bent. But are the same as each other.   The power storage device according to claim 1, wherein each of the electrodes includes an active material layer disposed on both surfaces of the current collecting base material.   At the ends of the positive electrode and the negative electrode alternately arranged in the stacking direction, the positive electrode current collecting base material as the current collecting base material is bent in the same direction, and the negative electrode current collecting base material as the current collecting base material is connected to the end portion. The power storage element according to claim 1, wherein the power storage element is bent in the same direction as a portion of the positive electrode current collection base material.   4. The power storage device according to claim 1, wherein each thickness of the positive electrode and the negative electrode is constant. 5. The power storage element according to any one of claims 1 to 4, wherein, in the stacked positive electrode and the negative electrode, an area of the active material layer of the negative electrode is larger than an area of the active material layer of the positive electrode.

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