JP6365175B2 - Electricity storage element - Google Patents

Description

  The present invention relates to a power storage device including an electrode body having a positive electrode and a negative electrode.

  An energy storage device including an electrode body formed by laminating a positive electrode, a negative electrode, and a separator is widely known. In such a power storage element, when the separator is damaged and the positive electrode and the negative electrode become conductive, an internal short circuit is caused.

  For this reason, conventionally, in order to prevent a short circuit between the positive electrode and the negative electrode, a power storage element in which an insulating layer is provided at a position where the positive electrode and the negative electrode are easily short-circuited has been proposed (for example, see Patent Document 1). In this power storage device, an insulating tape or the like is attached to the positive electrode base material layer to prevent a short circuit between the positive electrode base material layer and the negative electrode active material layer.

JP 2004-259625 A

  However, in the above conventional power storage element, there is a possibility that the insulating layer provided on the base material layer may be peeled off from the base material layer. Here, as a result of intensive studies and examinations, the inventors of the present application, when the insulating layer contains particles, compared with the adhesion between the active material layer and the base material layer, the insulating layer and the base material layer. It was found that the adhesiveness with was low. In addition, when the insulating layer is peeled off from the base material layer and the insulating layer contains particles, foreign matters such as particles contained in the insulating layer peeled off from the base material layer are diffused into the power storage element. And it discovered that there existed a possibility of leading to the fall of the performance of an electrical storage element. For example, the insulating layer may be peeled off from the base material layer in the process of assembling the electricity storage element, such as when the electrode body is pressed or wound.

  As described above, in the above-described conventional power storage element, in a configuration in which particles are included in the insulating layer formed on the positive electrode or negative electrode substrate layer, when the insulating layer is peeled off from the substrate layer, the insulating layer There is a problem that contained particles or the like may affect the power storage element.

  The present invention has been made to solve the above-described problem. Even when the insulating layer formed on the base layer of the positive electrode or the negative electrode includes particles, the particles included in the insulating layer are stored in the power storage element. It is an object of the present invention to provide a power storage element that can suppress the influence on the battery.

  In order to achieve the above object, a power storage device according to one embodiment of the present invention is a power storage device including an electrode body having a positive electrode and a negative electrode, and the positive electrode or the negative electrode includes a conductive base material layer, An active material layer formed on the base material layer, an insulating layer disposed on a predetermined direction side with respect to the active material layer on the base material layer and containing particles and a binder, the base material layer and the insulation An underlayer disposed between the end of the insulating layer and the end of the insulating layer at the same position as the end of the insulating layer or closer to the predetermined direction than the end of the insulating layer. An underlayer.

  According to this configuration, in the configuration in which the insulating layer includes particles, the base layer is disposed between the base material layer and the insulating layer, so that the insulating layer can be prevented from peeling from the base material layer. it can. Therefore, foreign matter such as particles contained in the insulating layer can be prevented from falling into the power storage element. For this reason, even when particles are included in the insulating layer formed on the base layer of the positive electrode or the negative electrode, it is possible to suppress the influence of the particles or the like included in the insulating layer on the power storage element.

  The underlayer may be disposed between the base material layer, the active material layer, and the insulating layer.

  According to this configuration, in the power storage element, since the base layer is disposed between the base material layer and the active material layer, not only the insulating layer but also the active material layer is peeled off from the base material layer. It can suppress falling in.

  The active material layer may be disposed between the base material layer and the insulating layer.

  According to this configuration, by disposing the insulating layer on the active material layer, the positive electrode and the negative electrode are short-circuited even when the separator is damaged in the portion of the active material layer where the insulating layer is disposed. Can be suppressed.

  The insulating layer and the base layer may both contain an aqueous binder as a binder having the same polarity, or both may contain a non-aqueous binder.

  According to this configuration, the insulating layer and the underlayer contain a binder having the same polarity, thereby improving the adhesion between the insulating layer and the underlayer and suppressing the peeling of the insulating layer from the base material layer. Can do.

  The active material layer may contain a binder having a polarity different from that of the insulating layer and the base layer.

  According to this configuration, since the active material layer contains a binder having a polarity different from that of the insulating layer and the base layer, the penetration from the insulating layer to the active material layer can be suppressed, and the charge and discharge can be effectively contributed. It can suppress that the area | region of an active material layer reduces. In addition, penetration of the active material layer into the insulating layer can be suppressed, and deterioration of the insulating property of the insulating layer can be suppressed.

  The electrode body has a flat surface portion and a curved surface portion formed by winding the positive electrode and the negative electrode, and the underlayer is disposed on at least a part of the flat surface portion. You may decide.

  Here, when the electrode body is a wound electrode body, for example, when the current collector is joined to the electrode body, the planar portion of the electrode body, which is the joining portion, is more from the base material layer than the curved surface portion. The insulating layer is easily peeled off. For this reason, it can suppress that an insulating layer peels from a base material layer by arrange | positioning a base layer in the plane part of the electrode body from which an insulating layer tends to peel from a base material layer.

  Note that the present invention can be realized not only as such a power storage element but also as an electrode body included in the power storage element.

  According to the electricity storage device of the present invention, even when particles are contained in the insulating layer formed on the positive electrode or negative electrode base material layer, the influence of the particles contained in the insulating layer on the electricity storage device is suppressed. Can do.

It is a perspective view which shows typically the external appearance of the electrical storage element which concerns on embodiment of this invention. It is a perspective view which shows the component arrange | positioned inside the container of the electrical storage element which concerns on embodiment of this invention. It is a perspective view which shows the structure of the electrode body which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the electrode body which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the edge part of the electrode body which concerns on embodiment of this invention. It is a perspective view which shows the arrangement position of the electrode body edge part shown by FIG. 5 in the electrode body which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the edge part of the electrode body which concerns on the modification 1 of embodiment of this invention. It is sectional drawing which shows the structure of the edge part of the electrode body which concerns on the modification 2 of embodiment of this invention. It is sectional drawing which shows the structure of the edge part of the electrode body which concerns on the modification 2 of embodiment of this invention. It is sectional drawing which shows the structure of the edge part of the electrode body which concerns on the modification 3 of embodiment of this invention.

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

(Embodiment)
First, the configuration of the power storage element 10 will be described.

  FIG. 1 is a perspective view schematically showing an external appearance of a power storage device 10 according to an embodiment of the present invention. FIG. 2 is a perspective view showing components disposed inside the container of power storage element 10 according to the embodiment of the present invention. Specifically, FIG. 2 is a perspective view illustrating a configuration in a state where the main body 111 of the container 100 is separated from the power storage element 10. FIG. 3 is a perspective view showing the configuration of the electrode assembly 400 according to the embodiment of the present invention. 3 is a partially developed view of the wound state of the electrode body 400 shown in FIG.

  The power storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. For example, the electric storage element 10 is applied to an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV). In addition, the electrical storage element 10 is not limited to a nonaqueous electrolyte secondary battery, A secondary battery other than a nonaqueous electrolyte secondary battery may be sufficient, and a capacitor may be sufficient as it. In addition, the shape of the electricity storage element 10 is not limited to a square shape, and may be a cylindrical or laminated electricity storage element.

  As shown in FIG. 1, the electricity storage device 10 includes a container 100, a positive electrode terminal 200, and a negative electrode terminal 300. As shown in FIG. 2, a positive electrode current collector 120, a negative electrode current collector 130, and an electrode body 400 are accommodated inside the container 100.

  In addition to the above components, spacers disposed on the sides of the positive electrode current collector 120 and the negative electrode current collector 130, a safety valve for releasing the pressure when the pressure in the container 100 rises, or An insulating film or the like surrounding the electrode body 400 may be disposed. In addition, a liquid such as an electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100 of the electricity storage element 10, but the illustration of the liquid is omitted. In addition, as long as the electrolyte solution enclosed with the container 100 does not impair the performance of the electrical storage element 10, there is no restriction | limiting in particular in the kind, Various things can be selected.

  The container 100 includes a main body 111 having a rectangular cylindrical shape and a bottom, and a lid 110 that is a plate-like member that closes an opening of the main body 111. In addition, the container 100 can be hermetically sealed by welding the lid body 110 and the main body 111 after the electrode body 400 and the like are accommodated therein. The material of the lid 110 and the main body 111 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, or aluminum alloy.

  The electrode body 400 includes a positive electrode, a negative electrode, and a separator, and is a member that can store electricity. The positive electrode is obtained by forming a positive electrode active material layer on a long belt-like positive electrode base material layer made of aluminum or an aluminum alloy. In the negative electrode, a negative electrode active material layer is formed on a long strip-shaped negative electrode base material layer made of copper, a copper alloy, or the like. The separator is a microporous sheet made of resin. The detailed configuration of the electrode body 400 will be described later.

  And as shown in FIG. 3, the electrode body 400 is formed by winding what is arranged in layers so that the separator is sandwiched between the positive electrode and the negative electrode. In the drawing, the shape of the electrode body 400 is oval, but it may be circular or elliptical. Further, the shape of the electrode body 400 is not limited to the winding type, and may be a shape in which flat plate plates are laminated.

  Returning to FIG. 2, the positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 400, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 400. That is, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 400 to the external space of the power storage element 10, and in order to store the electricity in the electrode body 400, It is an electrode terminal made of metal for introducing. Further, the positive electrode terminal 200 and the negative electrode terminal 300 are attached to the lid body 110 disposed above the electrode body 400.

  The positive electrode current collector 120 is disposed between the positive electrode of the electrode body 400 and the wall surface of the main body 111 of the container 100, and has electrical conductivity and rigidity that are electrically connected to the positive electrode terminal 200 and the positive electrode of the electrode body 400. It is a member provided. The positive electrode current collector 120 is made of aluminum, an aluminum alloy, or the like, like the positive electrode base material layer of the electrode body 400.

  The negative electrode current collector 130 is disposed between the negative electrode of the electrode body 400 and the wall surface of the main body 111 of the container 100, and has conductivity and rigidity electrically connected to the negative electrode terminal 300 and the negative electrode of the electrode body 400. It is a member provided. The negative electrode current collector 130 is formed of copper, a copper alloy, or the like, like the negative electrode base material layer of the electrode body 400.

  Specifically, the positive electrode current collector 120 and the negative electrode current collector 130 are metal plate-like members arranged in a bent state along the wall surface and the lid body 110 from the wall surface of the main body 111 to the lid body 110. It is. The positive electrode current collector 120 and the negative electrode current collector 130 are fixedly connected to the lid 110. The positive electrode current collector 120 and the negative electrode current collector 130 are fixedly connected to the positive electrode and the negative electrode of the electrode body 400, respectively. Examples of the fixed connection method include welding and ultrasonic welding. The electrode body 400 is held in a state suspended from the lid body 110 by the positive electrode current collector 120 and the negative electrode current collector 130 inside the container 100.

  Next, the configuration of the electrode body 400 will be described in detail.

  FIG. 4 is a cross-sectional view showing the configuration of the electrode body 400 according to the embodiment of the present invention. Specifically, FIG. 3 is a diagram showing a cross section when the portion where the winding state of the electrode body 400 shown in FIG. 3 is developed is cut along the AA cross section. FIG. 5 is a cross-sectional view showing a configuration of an end portion of the electrode body 400 according to the embodiment of the present invention. Specifically, this figure is an enlarged view of the electrode body end 401 shown in FIG.

  First, as shown in FIG. 4, the electrode body 400 is formed by laminating a positive electrode 410, a negative electrode 420, and two separators 430. Specifically, the separator 430, the negative electrode 420, the separator 430, and the positive electrode 410 are sequentially stacked in the Z-axis direction. Note that an end on the right side (X-axis direction plus side) of the electrode body 400 is an electrode body end 401, and an end on the left side (X-axis direction minus side) is an electrode body end 402.

  The electrode body end portion 401 is an end portion of the electrode body 400 connected to the positive electrode current collector 120, and the electrode body end portion 402 is an end portion of the electrode body 400 connected to the negative electrode current collector 130. Here, the electrode body end portion 401 will be described in detail below.

  As shown in FIG. 5, the positive electrode 410 includes a positive electrode base material layer 411, base layers 412 and 413, positive electrode active material layers 414 and 415, and insulating layers 416 and 417. In addition, the negative electrode 420 includes a negative electrode base material layer 421 and negative electrode active material layers 422 and 423. Note that an end portion of the base layer 412 of the positive electrode 410 is a base layer end portion 412a, and an end portion of the insulating layer 416 is an insulating layer end portion 416a.

  The positive electrode base material layer 411 is a long belt-shaped conductive current collector foil made of aluminum or an aluminum alloy. The negative electrode base material layer 421 is a long belt-shaped conductive current collector foil made of copper or a copper alloy. Note that as the current collector foil, a known material such as nickel, iron, stainless steel, titanium, baked carbon, a conductive polymer, conductive glass, or an Al—Cd alloy can be used as appropriate.

  The base layers 412 and 413 are coating layers disposed on the positive electrode base material layer 411. The underlayers 412 and 413 are disposed in contact with the positive electrode base material layer 411 by, for example, being directly applied to the positive electrode base material layer 411. Here, the base layer 412 is a layer disposed above the positive electrode base material layer 411 (Z-axis direction plus side in the figure), and the base layer 413 is below the positive electrode base material layer 411 (Z in the figure). It is a layer arranged on the negative side in the axial direction.

  Specifically, the base layer 412 is disposed between the positive electrode base material layer 411 and the insulating layer 416, more specifically, between the positive electrode base material layer 411, the positive electrode active material layer 414, and the insulating layer 416. Has been. Further, the base layer 413 is disposed between the positive electrode base material layer 411 and the insulating layer 417, more specifically, between the positive electrode base material layer 411, the positive electrode active material layer 415, and the insulating layer 417. .

  That is, the base layer 412 serves as a base for disposing (coating) the positive electrode active material layer 414 and the insulating layer 416 on the positive electrode base material layer 411. The positive electrode base material layer 411 and the positive electrode active material layer 414 are provided. And in contact with the insulating layer 416. The base layer 413 plays a role of a base for disposing (coating) the positive electrode active material layer 415 and the insulating layer 417 on the positive electrode base material layer 411. The positive electrode base material layer 411 and the positive electrode active material layer 415 are provided. And in contact with the insulating layer 417.

  In addition, the base layer 412 has a base layer end 412a which is an end of the base layer 412 in the predetermined direction, or the same position as the insulating layer end 416a which is an end of the insulating layer 416, or from the insulating layer end 416a. Is also arranged on the predetermined direction side. In this embodiment mode, the base layer 412 is disposed so that the base layer end portion 412a protrudes more in the predetermined direction than the insulating layer end portion 416a. That is, the base layer 412 is formed wider than the insulating layer 416. The same applies to the positional relationship between the base layer 413 and the insulating layer 417.

  Here, the predetermined direction is a direction from the center of the base material layer 411 toward the outside in a direction along the surface of the positive electrode base material layer 411 (parallel to the surface of the positive electrode base material layer 411). In the embodiment, it is the direction toward the X axis direction plus side. That is, the predetermined direction is a direction parallel to the winding axis of the electrode body 400 and is a direction from the electrode body end portion 402 of the electrode body 400 toward the electrode body end portion 401, and at the base layer end portion 412a, This is the direction away from the positive electrode active material layer 414.

  If the insulating layer is disposed so as to protrude in the predetermined direction from the base layer, the insulating layer protrudes from the base layer when the electrode body is joined to the current collector by ultrasonic welding or the like. The part (vibration or heat is transmitted to the part) may peel off. By disposing the base layer end portion 412a at the same position as the insulating layer end portion 416a or on the predetermined direction side with respect to the insulating layer end portion 416a, the electrode body and the current collector can be joined without peeling off the insulating layer. can do.

  The base layer end 412a is an end of the base layer 412 on the predetermined direction side, and the insulating layer end 416a is an end of the insulating layer 416 on the predetermined direction side.

  Here, the base layers 412 and 413 may be conductive layers containing a conductive material such as carbon and a binder. Examples of carbon include carbon blacks such as furnace black, acetylene black, and ketjen black, graphites such as powdered graphite and powdered expanded graphite, pulverized carbon fibers, and pulverized graphitized carbon fibers. it can. The base layers 412 and 413 may be formed by applying a paste containing a conductive material to the positive electrode base material layer 411, or may be formed by sputtering or the like.

  As described above, since the base layers 412 and 413 have conductivity, the internal resistance in the power storage element 10 can be reduced. In addition, the underlayers 412 and 413 may be mixed with lithium carbonate powder, polyolefin resin particles, or the like. Details of the binder contained in the base layers 412 and 413 will be described later.

  The positive electrode active material layers 414 and 415 are active material layers formed on the positive electrode base material layer 411. Specifically, the positive electrode active material layers 414 and 415 are formed on the base layers 412 and 413 formed on the positive electrode base material layer 411. That is, the positive electrode active material layers 414 and 415 are disposed in contact with the base layers 412 and 413, respectively, by being directly applied to the base layers 412 and 413, respectively.

  Specifically, the positive electrode active material layer 414 is an active material layer disposed above the base layer 412 (Z-axis direction plus side in the figure), and the positive electrode active material layer 415 is below the base layer 413 ( This is an active material layer disposed on the negative side in the Z-axis direction in FIG.

Here, the positive electrode active material layers 414 and 415 contain a positive electrode active material and a binder. As the positive electrode active material used for the positive electrode active material layers 414 and 415, a known material can be appropriately used as long as it is a positive electrode active material capable of occluding and releasing lithium ions. For example, a composite oxide represented by Li _x MO _y (M represents at least one transition metal) (Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , Li _x MnO ₃ , Li _x Ni _{y Co (1-y) O} 2, Li x Ni y Mn z Co , etc. _{(1-y-z) O} 2, Li x Ni y Mn (2-y) O 4), _or, Li _w Me x (XO _{y) z} (Me represents at least one transition metal, X is for example P, Si, B, polyanionic compound represented by _{V) (LiFePO 4, LiMnPO 4} , LiNiPO 4, LiCoPO 4, Li 3 V 2 (PO ₄ ) ₃ , Li ₂ MnSiO ₄ , Li ₂ CoPO ₄ F, etc.). The elements or polyanions in these compounds may be partially substituted with other elements or anion species, and the surface is coated with a metal oxide such as ZrO ₂ , MgO, Al ₂ O ₃ or carbon. Also good. Furthermore, conductive polymer compounds such as disulfide, polypyrrole, polyaniline, polyparastyrene, polyacetylene, and polyacene materials, pseudographite-structured carbonaceous materials, and the like are included, but the invention is not limited thereto. Moreover, these compounds may be used independently and may mix and use 2 or more types.

  Note that details of the binder contained in the positive electrode active material layers 414 and 415 will be described later.

  The insulating layers 416 and 417 are insulating layers formed on the positive electrode base material layer 411, and are in a predetermined direction side (X axis direction plus side) with respect to the positive electrode active material layers 414 and 415 on the positive electrode base material layer 411. ). Specifically, the insulating layers 416 and 417 are formed on the base layers 412 and 413 formed on the positive electrode base material layer 411, and the positive electrode active material layers 414 and 413 formed on the base layers 412 and 413 and The positive electrode active material layers 414 and 415 are disposed adjacent to the positive electrode active material layers 414 and 415 on the predetermined direction side with respect to 415. That is, the insulating layers 416 and 417 are disposed in contact with the base layers 412 and 413 by being applied directly to the positive electrode active material layers 414 and 415 of the base layers 412 and 413 in the predetermined direction.

  Specifically, the insulating layer 416 is an insulating coating layer disposed above the base layer 412 (the Z-axis direction plus side in the figure), and on the positive side of the positive electrode active material layer 414 in the X-axis direction plus side. It is disposed adjacent to the material layer 414. The insulating layer 417 is an insulating coating layer disposed below the base layer 413 (in the Z-axis direction minus side in the figure), and on the positive side of the positive electrode active material layer 415 in the X-axis direction, the positive electrode active material layer 415. And is placed adjacent.

  Note that the insulating layers 416 and 417 may be formed so as to be thinner than the positive electrode active material layers 414 and 415 (the height in the Z-axis direction is low). With this configuration, the insulating layers 416 and 417 do not press the separator 430 when the electrode body is wound or pressed, and the positive electrode base material layer 411 is broken due to local pressure, or the separator 430. It is possible to prevent a short circuit due to breakage.

Here, the insulating layers 416 and 417 contain particles such as inorganic particles and a binder. The inorganic particles used for the insulating layers 416 and 417 are not particularly limited. For example, alumina, silica, zirconia, titania, magnesia, ceria, yttria, zinc oxide, iron oxide, barium titanium oxide, alumina -Covalent bonds of oxides such as silica composite oxides, nitrides such as silicon nitride, titanium nitride, boron nitride and aluminum nitride, sparingly soluble ionic crystals such as calcium fluoride, barium fluoride and barium sulfate, silicon and diamond Crystal, silicon carbide, calcium carbonate, aluminum sulfate, aluminum hydroxide, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amicite, bentonite, asbestos, zeolite, Ke Calcium, magnesium silicate, boehmite, apatite, mullite, spinel, olivine, etc., or compounds containing them, and the like. In addition, the above-mentioned inorganic substance is made of an electrically insulating material such as SnO ₂ , an oxide such as tin-indium oxide (ITO), a carbonaceous material such as carbon black, graphite, or the like. It may be a particle that has been made electrically insulating by surface treatment with the above-described material constituting the electrically insulating inorganic particles.

  Note that the insulating layers 416 and 417 may contain organic particles instead of inorganic particles. Details of the binder contained in the insulating layers 416 and 417 will be described later.

  The negative electrode active material layers 422 and 423 are active material layers formed on the negative electrode base material layer 421. Specifically, the negative electrode active material layer 422 is an active material layer disposed above the negative electrode base material layer 421 (the Z-axis direction plus side in the figure), and the negative electrode active material layer 423 is a negative electrode base material layer. This is an active material layer disposed below 421 (in the negative Z-axis direction in the figure). Note that the negative electrode 420 may have a base layer between the negative electrode base material layer 421 and the negative electrode active material layers 422 and 423 similarly to the positive electrode 410.

Here, the negative electrode active material layers 422 and 423 contain a negative electrode active material and a binder. As the negative electrode active material used for the negative electrode active material layers 422 and 423, a known material can be appropriately used as long as it is a negative electrode active material capable of occluding and releasing lithium ions. For example, lithium metal and lithium alloys (lithium metal-containing alloys such as lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloys) and lithium can be occluded / released. Alloys, carbon materials (for example, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), metal oxides, lithium metal oxides (Li ₄ Ti ₅ O ₁₂ etc.), polyphosphate compounds Etc. Among these, graphite, non-graphitizable carbon, and graphitizable carbon are particularly preferable. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio.

  As the binder used for the negative electrode active material layers 422 and 423, the same binder as that used for the positive electrode active material layers 414 and 415 can be used.

  The separator 430 is a microporous sheet made of resin, and is impregnated with an electrolytic solution containing an organic solvent and an electrolyte salt. Here, as the separator 430, a synthetic resin microporous film made of a polyolefin resin such as a woven fabric, a non-woven fabric, or polyethylene that is insoluble in an organic solvent is used, and a plurality of microporous films having different materials, weight average molecular weights and porosity are used. Are laminated, and those microporous membranes contain appropriate amounts of additives such as various plasticizers, antioxidants, flame retardants, and inorganic oxides such as silica are coated on one and both sides. It may be a thing. In particular, a synthetic resin microporous film can be suitably used. Among them, polyolefin-based microporous membranes such as polyethylene and polypropylene microporous membranes, polyethylene and polypropylene microporous membranes combined with aramid and polyimide, or microporous membranes that combine these, have thickness, membrane strength, membrane It is preferably used in terms of resistance.

  Next, binders included in the base layers 412 and 413, the positive electrode active material layers 414 and 415, and the insulating layers 416 and 417 will be described.

  The base layers 412 and 413 and the insulating layers 416 and 417 contain a binder having the same polarity. Specifically, the base layers 412 and 413 and the insulating layers 416 and 417 both contain an aqueous binder (aqueous binder), or both contain a non-aqueous binder (non-aqueous binder).

  The positive electrode active material layers 414 and 415 contain a binder having a polarity different from the binder contained in the base layers 412 and 413 and the insulating layers 416 and 417. That is, when both the base layers 412 and 413 and the insulating layers 416 and 417 contain an aqueous binder, the positive electrode active material layers 414 and 415 contain a non-aqueous binder. In addition, when both the base layers 412 and 413 and the insulating layers 416 and 417 contain a non-aqueous binder, the positive electrode active material layers 414 and 415 contain an aqueous binder.

  Here, the aqueous binder is a binder that is dispersed or dissolved in water. As the water-based binder, a water-soluble binder (water-based binder that dissolves in water) that dissolves 1 part by mass or more with respect to 100 parts by mass of water at 20 ° C. is preferable. For example, as the water-based binder, polyethylene oxide (polyethylene glycol), polypropylene oxide (polypropylene glycol), polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), polyolefin, nitrile -Preferably at least one selected from the group consisting of butadiene rubber and cellulose, at least selected from the group consisting of polyethylene oxide (polyethylene glycol), polypropylene oxide (polypropylene glycol), polyvinyl alcohol, polyacrylic acid, polymethacrylic acid One type of water-soluble binder is more preferable.

  The non-aqueous binder is a binder (solvent binder) having a lower water solubility than that of the aqueous binder. As a non-aqueous binder, what melt | dissolves less than 1 mass part with respect to 100 mass parts of water in 20 degreeC is preferable. For example, non-aqueous binders include polyvinylidene fluoride (PVDF), a copolymer of vinylidene fluoride and hexafluoropropylene, a copolymer of ethylene and vinyl alcohol, polyacrylonitrile, polyphosphazene, polysiloxane, polyacetic acid. Examples thereof include vinyl, polymethyl methacrylate, polystyrene, polycarbonate, polyamide, polyimide, polyamideimide, a crosslinked polymer of cellulose and chitosan pyrrolidone carboxylate, and chitin or chitosan derivatives. Examples of the chitosan derivative include a polymer compound obtained by glycerylating chitosan, and a cross-linked product of chitosan.

  Note that when the base layers 412 and 413 contain a non-aqueous binder, the non-aqueous binder has higher affinity with the carbonaceous material, and the carbonaceous material diffuses into the insulating layers 416 and 417. At least one selected from the group consisting of polyvinylidene fluoride, chitosan derivatives, and polyimide is preferable in that it can be further suppressed.

  Further, when the positive electrode active material layers 414 and 415 contain a non-aqueous binder, the non-aqueous binder may be polyvinylidene fluoride or ethylene in terms of excellent binding properties or low electrical resistance. At least one selected from the group consisting of a copolymer of styrene and vinyl alcohol and polymethyl methacrylate is preferred.

  Next, in the electrode body 400, the position where the configuration of the electrode body end portion 401 described in FIG. 5 is arranged will be described.

  FIG. 6 is a perspective view showing an arrangement position of the electrode body end portion 401 shown in FIG. 5 in the electrode body 400 according to the embodiment of the present invention.

  As shown in the drawing, the electrode body end portion 401 of the electrode body 400 has a flat surface portion 401a and a curved surface portion 401b formed by winding a positive electrode 410, a negative electrode 420, and a separator 430. . That is, the electrode body 400 has a configuration in which the positive electrode 410, the negative electrode 420, and the separator 430 are stacked in an oval shape when viewed from a direction parallel to the winding axis (X-axis direction). The region in the electrode body end portion 401 corresponding to the elliptical straight portion, and the curved surface portion 401b is a region in the electrode body end portion 401 corresponding to the elliptical curved portion.

  Then, the base layers 412 and 413 shown in FIG. 5 are arranged on the flat portion 401a. That is, the configuration of the electrode body end portion 401 shown in FIG. 5 (the configuration in which the base layers 412 and 413 protrude from the insulating layers 416 and 417 to the plus side in the X-axis direction) is disposed in the plane portion 401a. The

  Note that the configuration of the electrode body end portion 401 shown in FIG. 5 is only required to be disposed in at least a part of the flat surface portion 401a, and may be disposed in all regions in the flat surface portion 401a. A configuration in which only a part of the area 401a is arranged may be used. That is, a configuration different from the configuration (for example, a configuration in which the insulating layers 416 and 417 are disposed so as to protrude to the plus side in the X-axis direction from the base layers 412 and 413) exists in the plane portion 401a. It doesn't matter.

  Further, the configuration of the electrode body end portion 401 shown in FIG. 5 may also be arranged in the curved surface portion 401b, but the region where the configuration is arranged in the flat surface portion 401a is in the curved surface portion 401b. It is preferable that the area is larger than the area where the structure is arranged.

  Next, the manufacturing method of the electrical storage element 10 is demonstrated in detail. First, a method for manufacturing the electrode body 400 will be described.

  The method for manufacturing the electrode body 400 includes, for example, a negative electrode manufacturing process for manufacturing the negative electrode 420, a positive electrode manufacturing process for manufacturing the positive electrode 410, and an overlapping process for stacking the negative electrode 420 and the positive electrode 410.

  In the negative electrode manufacturing step, negative electrode active material layers 422 and 423 are formed. For example, a negative electrode active material and a binder are mixed, and the mixture is added to a solvent and kneaded to prepare a negative electrode mixture. This negative electrode mixture is applied to the strip-shaped negative electrode substrate layer 421. Then, the solvent is volatilized from the applied negative electrode mixture. Thus, the negative electrode 420 in which the negative electrode active material layers 422 and 423 are formed on the negative electrode base material layer 421 is manufactured.

  The positive electrode manufacturing step includes a base layer forming step, a positive electrode active material layer forming step, and an insulating layer forming step.

  In the underlayer forming step, for example, a carbonaceous material and a binder are mixed, and this mixture is added to a solvent and kneaded to prepare an underlayer composition. This underlayer composition is applied to the positive electrode base material layer 411. Furthermore, the base layers 412 and 413 are formed on the positive electrode base material layer 411 by volatilizing the solvent from the applied base layer composition.

  In the positive electrode active material layer forming step, for example, a positive electrode active material, a conductive additive, and a binder are mixed, and the mixture is added to a solvent and kneaded to prepare a positive electrode mixture. This positive electrode mixture is applied on the positive electrode base material layer 411 or the base layers 412 and 413. Then, the solvent is volatilized from the applied positive electrode mixture. In addition, when apply | coating a positive mix on base layer 412, 413, the composition for base layers may still contain the solvent, and the solvent has already volatilized from the composition for base layers by drying. Also good.

  In the insulating layer forming step, for example, an insulating material and a binder are mixed, and the mixture is added to a solvent and kneaded to prepare an insulating layer composition. This composition for insulating layers is applied on the underlayers 412 and 413 or the positive electrode active material layers 414 and 415. And a solvent is volatilized from the apply | coated composition for insulating layers. When applying the insulating layer composition, the positive electrode mixture or the underlayer composition may still contain a solvent, and the solvent has already been volatilized from the positive electrode mixture or the underlayer composition by drying. Also good.

  In the positive electrode manufacturing step, each step can be performed separately. Specifically, the positive electrode active material layer forming step can be performed after the solvent is volatilized from the base layer composition in the base layer forming step. And after evaporating a solvent from a positive mix in a positive electrode active material layer formation process, an insulating layer formation process can be performed.

  On the other hand, in a positive electrode preparation process, after apply | coating the composition for base layers in a base layer formation process, a positive electrode active material layer formation process and an insulating layer formation process can be performed simultaneously. That is, the positive electrode mixture is formed along the longitudinal direction of the strip-shaped positive electrode base material layer 411 so that the positive electrode mixture and the insulating layer composition are adjacent to each other before the solvent is completely evaporated from the underlayer composition. The agent and the insulating layer composition can be applied simultaneously.

  In addition, a general method is employ | adopted as a coating method in a positive electrode preparation process or a negative electrode preparation process.

  In the overlapping step, the positive electrode 410 and the negative electrode 420 are disposed so that the positive electrode active material layer and the negative electrode active material layer face each other, and the separator 430 is disposed between the positive electrode 410 and the negative electrode 420. Further, the positive electrode 410 and the negative electrode 420 are arranged and overlapped on one side in the width direction of the negative electrode base material layer 421 so that the edges of the negative electrode active material layers 422 and 423 face the insulating layers 416 and 417 of the positive electrode 410. Match.

  Next, the positive electrode current collector 120 and the negative electrode current collector 130 are attached to each of the positive electrode 410 and the negative electrode 420 in the electrode body 400 manufactured as described above. Next, the electrode body 400 and the positive electrode current collector 120 and the negative electrode current collector 130 attached to the electrode body 400 are arranged inside the main body 111 of the container 100. When there are a plurality of electrode bodies 400, for example, the positive electrode current collector 120 and the negative electrode current collector 130 of the electrode body 400 are electrically connected in parallel and arranged inside the main body 111. Next, the positive electrode current collector 120 and the negative electrode current collector 130 are respectively connected to the positive electrode terminal 200 and the negative electrode terminal 300 attached to the lid body 110 by caulking or welding the rivets, and then the lid body 110 is attached. Attached to the main body 111.

  Subsequently, an electrolytic solution is injected into the container 100 from a liquid injection hole provided in the container 100. Then, the liquid injection hole is sealed.

  Thus, the electrical storage element 10 can be manufactured.

  As described above, according to power storage element 10 according to the embodiment of the present invention, positive electrode 410 has insulating layers 416 and 417 arranged on the sides of positive electrode active material layers 414 and 415 on positive electrode base material layer 411. And underlayers 412 and 413 disposed between the positive electrode base material layer 411 and the insulating layers 416 and 417. The insulating layers 416 and 417 contain particles and a binder, and the base layers 412 and 413 are arranged such that the end portions protrude from the end portions of the insulating layers 416 and 417. For this reason, in the structure in which the insulating layers 416 and 417 include particles, the base layers 412 and 413 are disposed at the end portions of the insulating layers 416 and 417. Therefore, the base layers 412 and 413 cause the insulating layers 416 and 417 to be separated. Can be prevented from peeling off from the positive electrode base material layer 411. Therefore, foreign matters such as particles contained in the insulating layers 416 and 417 can be prevented from falling into the power storage element 10. Therefore, even when the insulating layers 416 and 417 formed on the positive electrode base material layer 411 of the positive electrode 410 include particles, the influence of the particles or the like included in the insulating layers 416 and 417 on the power storage element 10 can be suppressed. it can.

  The positive electrode base material layer 411 is made of metal and thus has a smooth surface, while the surfaces of the base layers 412 and 413 are rough to some extent. Here, since the adhesiveness is improved when formed on a rough surface rather than a smooth surface, it is considered that the insulating layers 416 and 417 are formed on the base layers 412 and 413, thereby improving the adhesiveness. . In general, the base layers 412 and 413 are formed thinner than the insulating layers 416 and 417 (thickness in the Z-axis direction in FIG. 5), but the layers formed on the positive electrode base material layer 411 are The thinner one tends to increase the adhesion. Accordingly, it is presumed that the base layers 412 and 413 can suppress the insulating layers 416 and 417 from being peeled off from the positive electrode base material layer 411.

  In the power storage element 10, the base layers 412 and 413 are also disposed between the positive electrode base material layer 411 and the positive electrode active material layers 414 and 415. Therefore, not only the insulating layers 416 and 417 but also the positive electrode active material layer 414. 415 and 415 can be prevented from being peeled off from the positive electrode base material layer 411 and falling into the power storage element 10.

  In addition, since the insulating layers 416 and 417 and the base layers 412 and 413 contain a binder having the same polarity, adhesion between the insulating layers 416 and 417 and the base layers 412 and 413 is improved, and the insulating layers 416 and 417 are included. Can be prevented from peeling off from the positive electrode base material layer 411.

  In addition, since the positive electrode active material layers 414 and 415 contain a binder having a polarity different from that of the insulating layers 416 and 417 and the base layers 412 and 413, the positive electrode active material layers 414 and 415 are immersed in the positive electrode active material layers 414 and 415. It is possible to suppress the penetration and to suppress the reduction of the active material layer region that can effectively contribute to charging and discharging. In addition, penetration of the positive electrode active material layers 414 and 415 into the insulating layers 416 and 417 can be suppressed, and deterioration of the insulating properties of the insulating layers 416 and 417 can be suppressed.

  Further, when the electrode body 400 is a wound electrode body, for example, when the positive electrode current collector 120 is joined to the electrode body 400, the flat surface portion 401a of the electrode body 400 that is a joining portion is more than the curved surface portion 401b. Peeling of the insulating layers 416 and 417 from the positive electrode base material layer 411 is likely to occur. For this reason, the base layers 412 and 413 are disposed on the flat surface portion 401a where the insulating layers 416 and 417 are easily peeled off from the positive electrode base material layer 411, so that the insulating layers 416 and 417 are prevented from peeling off from the positive electrode base material layer 411. be able to.

(Modification 1)
Next, Modification 1 of the above embodiment will be described. FIG. 7 is a cross-sectional view showing a configuration of an end portion (electrode body end portion 403) of the electrode body according to Modification 1 of the embodiment of the present invention.

  As shown in the figure, the electrode body according to this modification includes an electrode body end 403 instead of the electrode body end 401 of the electrode body 400 according to the above embodiment. In addition, the electrode body end portion 403 includes base layers 441 and 442 instead of the base layers 412 and 413 of the electrode body end portion 401 according to the above embodiment. The other configuration is the same as the configuration of the electrode body end portion 401 of the electrode body 400 according to the above embodiment, and thus detailed description thereof is omitted.

  The base layer 441 is arranged such that an end portion (base layer end portion 441a) is located at the same position as an end portion (insulating layer end portion 416a) of the insulating layer 416 in a predetermined direction. That is, in this modification, the base layer 441 is disposed between the positive electrode base material layer 411 and the insulating layer 416, but the base layer end portion 441a does not protrude from the insulating layer end portion 416a. The same applies to the base layer 442. The predetermined direction is the central portion of the base material layer 411 in an arbitrary direction along the surface of the positive electrode base material layer 411 (parallel to the surface of the positive electrode base material layer 411), as in the above embodiment. Direction toward the outside, specifically, the direction toward the X-axis direction plus side.

  As described above, according to the electricity storage device according to this modification, the same effects as those of the above-described embodiment can be obtained. In particular, the base layers 441 and 442 are arranged at the same position as the end portions of the insulating layers 416 and 417 without protruding from the end portions of the insulating layers 416 and 417. The amount used can be reduced.

(Modification 2)
Next, a second modification of the above embodiment will be described. 8A and 8B are cross-sectional views showing the configuration of the end portions (electrode body end portions 404 and 405) of the electrode body according to Modification 2 of the embodiment of the present invention.

  As shown in these drawings, the electrode body according to this modification includes an electrode body end 404 or 405 instead of the electrode body end 401 of the electrode body 400 according to the above-described embodiment.

  First, as shown in FIG. 8A, the electrode body end portion 404 is formed by replacing the underlayers 412 and 413 and the positive electrode active material layers 414 and 415 of the electrode body end portion 401 according to the above embodiment with the underlayer 451 and 452 and positive electrode active material layers 453 and 454. The other configuration is the same as the configuration of the electrode body end portion 401 of the electrode body 400 according to the above embodiment, and thus detailed description thereof is omitted.

  The base layers 451 and 452 are disposed between the positive electrode base material layer 411 and the insulating layers 416 and 417 without being disposed between the positive electrode base material layer 411 and the positive electrode active material layers 453 and 454. That is, the positive electrode active material layers 453 and 454 are disposed in contact with the positive electrode base material layer 411, and the base layers 451 and 452 are disposed on the positive side of the positive electrode active material layers 453 and 454 on the positive side in the X-axis direction. It is disposed in contact with the material layer 411.

  Similarly to the above embodiment, the base layer 451 is disposed so that the base layer end 451a protrudes to the plus side in the X-axis direction from the insulating layer end 416a. The same applies to the base layer 452.

  Further, as shown in FIG. 8B, the electrode body end portion 405 includes base layers 455 and 456 instead of the base layers 451 and 452 of the electrode body end portion 404 described above. Other configurations are the same as the configurations of the electrode body end portion 404, and thus detailed description thereof is omitted.

  As in the first modification, the base layer 455 has a base layer end 455a that does not protrude from the insulating layer end 416a in the predetermined direction (the direction toward the X-axis direction plus side). Arranged at the same position. The same applies to the base layer 456.

  As described above, according to the electricity storage device according to this modification, the same effects as those of the above-described embodiment and modification 1 are obtained. In particular, the insulating layers 416 and 417 are more easily separated from the positive electrode base material layer 411 than the positive electrode active material layers 453 and 454. Therefore, the base layer is arranged at least between the insulating layers 416 and 417 and the positive electrode base material layer 411 and is not arranged between the positive electrode base material layer 411 and the positive electrode active material layers 453 and 454. Thereby, it can suppress that an insulating layer peels from a base material layer, reducing the usage-amount of a base layer.

(Modification 3)
Next, Modification 3 of the above embodiment will be described. FIG. 9 is a cross-sectional view showing a configuration of an end portion (electrode body end portion 406) of the electrode body according to Modification 3 of the embodiment of the present invention.

  As shown in the figure, the electrode body according to this modification includes an electrode body end 406 instead of the electrode body end 401 of the electrode body 400 according to the above embodiment.

  The electrode body end 406 is replaced with the base layers 461 and 462 and the positive electrode instead of the base layers 412 and 413, the positive electrode active material layers 414 and 415, and the insulating layers 416 and 417 of the electrode body end 401 according to the above embodiment. Active material layers 463 and 464 and insulating layers 465 and 466 are provided. The other configuration is the same as the configuration of the electrode body end portion 401 of the electrode body 400 according to the above embodiment, and thus detailed description thereof is omitted.

  The base layers 461 and 462 are disposed between the positive electrode substrate layer 411 and the insulating layers 465 and 466 without being disposed between the positive electrode substrate layer 411 and the positive electrode active material layers 463 and 464. That is, the positive electrode active material layers 463 and 464 are disposed in contact with the positive electrode base material layer 411, and the base layers 461 and 462 are disposed on the positive side of the positive electrode active material layers 463 and 464 on the positive side in the X-axis direction. It is disposed in contact with the material layer 411.

  The positive electrode active material layers 463 and 464 are arranged between the positive electrode base material layer 411 and the insulating layers 465 and 466. That is, the insulating layers 465 and 466 are disposed in contact with the base layers 461 and 462 and are also disposed in contact with the positive electrode active material layers 463 and 464.

  Specifically, the insulating layer 465 is disposed above the positive electrode active material layer 463 (Z-axis direction plus side) and on a predetermined direction side (X-axis direction plus side) from the positive electrode active material layer 463. The insulating layer 466 is disposed below the positive electrode active material layer 464 (Z-axis direction minus side) and on a predetermined direction side (X-axis direction plus side) from the positive electrode active material layer 464.

  Similarly to the above embodiment, the base layer 461 is disposed so that the base layer end 461a protrudes to the plus side in the X-axis direction from the insulating layer end 465a. The same applies to the base layer 462.

  Note that, as in the first modification, the base layer 461 does not protrude from the insulating layer end 465a in the predetermined direction (the direction toward the X-axis direction plus side), and the insulating layer end 461a. It may be configured to be arranged at the same position as 465a. The same applies to the base layer 462.

  As described above, according to the electricity storage device according to this modification, the same effects as those of the above-described embodiment and modification 1 are obtained. In particular, by disposing the insulating layers 465 and 466 on the positive electrode active material layers 463 and 464, even when the separator 430 is damaged or the like in the portion where the insulating layers 465 and 466 of the positive electrode active material layers 463 and 464 are disposed. The short circuit between the positive electrode 410 and the negative electrode 420 can be suppressed.

  In the configuration of the above-described embodiment shown in FIG. 5, the insulating layers 416 and 417 may be arranged in contact with the positive electrode active material layers 414 and 415. That is, in the configuration shown in FIG. 5, the insulating layers 416 and 417 are disposed in contact with the base layers 412 and 413 and are also disposed in contact with the positive electrode active material layers 414 and 415. It does not matter if it is configured.

  Although the power storage device according to the embodiment of the present invention and the modification thereof has been described above, the present invention is not limited to the above-described embodiment and the modification. In other words, it should be considered that the embodiment and its modification disclosed this time are illustrative and not restrictive in all respects. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  For example, in the embodiment and the modification thereof, the configuration of the portion on the electrode body end portion 401 side of the positive electrode 410 has been described. However, the portion on the electrode body end portion 402 side of the positive electrode 410 also includes the electrode body end portion 401 side. You may decide to have the same composition. Further, instead of the configuration of the portion of the positive electrode 410 on the electrode body end portion 401 side, the portion of the positive electrode 410 on the electrode body end portion 402 side may have the configuration. Alternatively, the configuration may be formed along the width direction of the positive electrode or the negative electrode at the winding start portion or the winding end portion of the electrode body 400.

  In the above embodiment and its modification, the positive electrode 410 includes the base layer and the insulating layer, but the negative electrode 420 includes the base layer and the insulating layer. You may decide to have a structure. Alternatively, both the positive electrode 410 and the negative electrode 420 may have the above-described configuration.

  In the above embodiment and its modification, the positive electrode active material layer contains a binder having a polarity different from that of the insulating layer and the base layer. However, the positive electrode active material layer is the same as the base layer and the insulating layer. You may decide to contain a polar binder. That is, the positive electrode active material layer, the base layer, and the insulating layer may all contain an aqueous binder, or may all contain a non-aqueous binder.

  In the above-described embodiment and its modification, the insulating layer and the base layer contain binders having the same polarity, but the insulating layer and the base layer contain binders having different polarities. May be.

  Moreover, the form constructed | assembled combining the said embodiment and the said modification arbitrarily is also contained in the scope of the present invention.

  In addition, the present invention can be realized not only as such a power storage element but also as an electrode body 400 included in the power storage element.

  The present invention can also be realized as a power storage device including a plurality of the power storage elements. The power storage device includes a plurality of power storage units, and the power storage units include a plurality of nonaqueous electrolyte secondary batteries as a plurality of power storage elements. The power storage device can be effectively used as a power source for vehicles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV), a power source for electronic devices, a power storage power source, and the like. When used as the power storage device, it can be mounted as a battery module (assembled battery) having a plurality of batteries.

  The present invention can be applied to a power storage element or the like that can suppress the influence of particles or the like included in the insulating layer even when the insulating layer formed on the base layer of the positive electrode or the negative electrode includes particles.

DESCRIPTION OF SYMBOLS 10 Power storage element 100 Container 110 Cover body 111 Main body 120 Positive electrode current collector 130 Negative electrode current collector 200 Positive electrode terminal 300 Negative electrode terminal 400 Electrode body 401, 402, 403, 404, 405, 406 Electrode body end part 401a Flat surface part 401b Curved surface part 410 Positive electrode 411 Positive electrode base material layer 412, 413, 441, 442, 451, 452, 455, 456, 461, 462 Underlayer 412a, 441a, 451a, 455a, 461a Underlayer edge 414, 415, 453, 454, 463 464 Positive electrode active material layer 416, 417, 465, 466 Insulating layer 416a, 465a Insulating layer end 420 Negative electrode 421 Negative electrode base material layer 422, 423 Negative electrode active material layer 430 Separator

Claims (4)

A power storage device comprising an electrode body having a positive electrode and a negative electrode,
The positive electrode or the negative electrode is
A conductive substrate layer;
An active material layer formed on the base material layer;
An insulating layer disposed on a predetermined direction side of the active material layer on the base material layer and containing particles and a binder;
The underlayer is disposed between the base material layer and the insulating layer and contains a conductive material and a binder, and in the predetermined direction, the end is the same position as the end of the insulating layer, or the than the end of the insulating layer have a an underlying layer disposed on the predetermined direction,
The insulating layer and the base layer both contain an aqueous binder as a binder of the same polarity, or both contain a non-aqueous binder,
The water-based binder is a binder that is dispersed or dissolved in water, and the non-aqueous binder is a binder that is dissolved in less than 1 part by mass with respect to 100 parts by mass of water at 20 ° C.   The power storage element according to claim 1, wherein the base layer is disposed between the base material layer, the active material layer, and the insulating layer.   The power storage element according to claim 1, wherein the active material layer is disposed between the base material layer and the insulating layer. The electrode body has a flat surface portion and a curved surface portion formed by winding the positive electrode and the negative electrode,
The underlying layer, the disposed on at least a portion of the flat portion, the electric storage device according to any one of claims 1-3.

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