JP2017143004A - Power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure stable insulation by suppressing the falling of an isolation layer.SOLUTION: A power storage element 10 comprises an electrode body having electrode plates (a positive electrode plate 410 and a negative electrode plate 420). The electrode plates has: a conductive base material layer (a positive electrode base material layer 411); a mixture layer (a positive electrode mixture layer 414) formed on the base material layer; and an isolation layer 415 at least partially formed on the base material layer. The isolation layer 415 has a flexible part 419 which is more flexible than other parts.SELECTED DRAWING: Figure 5

Description

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

  Conventionally, a storage element such as a lithium ion secondary battery has, for example, a positive electrode plate, a negative electrode plate, and an electrode body in which a separator disposed between the positive electrode plate and the negative electrode plate is stacked. With respect to the electrode body having such a configuration in which a positive electrode plate, a negative electrode plate, and a separator are laminated, a technique related to prevention of a short circuit between the positive electrode plate and the negative electrode plate has been conventionally disclosed.

  For example, Patent Literature 1 discloses a lithium ion secondary battery including an insulating layer formed so as to cover an active material layer in a negative electrode plate. This insulating layer prevents a short circuit between the positive electrode plate and the negative electrode plate.

JP2013-232425A

  By the way, when a physical load acts on the insulating layer, the insulating layer falls off and there is a possibility that stable insulating properties cannot be secured.

  For this reason, this invention is providing the electrical storage element which can ensure the stable insulation by suppressing the drop-off | omission of an insulating layer.

  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 plate, and the plate is formed on a conductive base material layer and a base material layer. The formed composite material layer has an insulating layer at least partially formed on the base material layer, and the insulating layer has a flexible portion that is more flexible than the other portions.

  Thus, since the insulating layer has a flexible part that is more flexible than other parts, the presence of the flexible part has the property that the entire insulating layer easily deforms following the base material layer. Thereby, even if a physical load acts on the insulating layer, the insulating layer can be prevented from falling off from the base material layer. Therefore, stable insulation can be ensured.

  Further, the flexible part may be a part including a groove part formed in the insulating layer.

  According to this, since the flexible portion is a portion including the groove portion formed in the insulating layer, the groove portion can be easily formed by simply drying the insulating paste at the time of manufacture, and thus the flexible portion is easily formed. be able to.

  Further, the insulating layer may be provided continuously with respect to the entire composite material layer, and the flexible portion may be provided in at least a part of a region corresponding to the flat portion of the electrode body in the insulating layer.

  According to this, since the flexible part is provided in the area | region corresponding to the flat part in an insulating layer, drop-off | omission of the insulating layer in the said area | region can be suppressed.

  Moreover, the insulating layer may be continuously formed on the edge part which is a part containing the edge of a compound material layer.

  According to this, since the insulating layer is formed on the edge part which is a part including the edge of the composite material layer continuously from the base material layer, the composite material layer is expanded and contracted by charging and discharging. However, the stress generated between the insulating layer and the composite layer can be relaxed.

  Moreover, the flexible part may be provided in the edge part in an insulating layer, and at least one part of the area | region corresponding to the said base material layer.

  According to this, since the flexible part is provided in at least a part of the region corresponding to the edge portion and the base material layer in the insulating layer, it is possible to suppress the falling off of the insulating layer in the region.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage element which can ensure the stable insulation can be provided by suppressing the drop-off | omission of an insulating layer.

It is a perspective view which shows the external appearance of the electrical storage element which concerns on embodiment. It is a perspective view which shows the component arrange | positioned in the container of the electrical storage element which concerns on embodiment. It is a perspective view which shows the structure outline | summary of the electrode body which concerns on embodiment. It is sectional drawing which shows the structure outline | summary of the electrode body which concerns on embodiment. It is a figure which shows the cross-sectional shape example of the positive mix layer and insulating layer which concern on embodiment. It is an enlarged view which shows the surface shape of the 1st area | region of the insulating layer which concerns on embodiment. It is a table | surface which shows whether the ratio of the particle | grains which comprise the insulating layer which concerns on an Example, and a binder was varied, and the insulating layer fell out in each ratio. It is a table | surface which shows whether the thickness of the insulating layer which concerns on an Example was varied and the insulating layer fell out in each thickness. It is sectional drawing which shows the case where the insulating layer which concerns on a modification has covered the whole region of the positive mix layer. It is an enlarged view which shows the case where the groove part which concerns on a modification is extended in the vertical direction. It is an enlarged view which shows the case where the groove part which concerns on a modification is extended in the horizontal direction.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. Each figure is a schematic diagram and is not necessarily illustrated exactly.

  The embodiment described below shows a specific example of the present invention. The shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, order of manufacturing steps, 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.

  First, with reference to FIG. 1 and FIG. 2, a general description of the energy storage device 10 according to the embodiment will be given.

  FIG. 1 is a perspective view showing an external appearance of a power storage element 10 according to the embodiment. FIG. 2 is a perspective view showing components arranged in the container of power storage element 10 according to the embodiment. Specifically, FIG. 2 is a perspective view showing the electricity storage device 10 with the lid 110 and the main body 111 of the container 100 separated.

  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. Further, the shape of the electricity storage element 10 is not limited to a square shape, and may be another shape such as a cylindrical shape.

  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 in the container 100.

  In addition to the above-described components, the storage element 10 is a spacer disposed on the side of the positive electrode current collector 120 and the negative electrode current collector 130, and releases the pressure when the pressure in the container 100 increases. A safety valve or an insulating film that wraps around the electrode body 400 or the like may be provided. 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 has a structure in which the interior of the container 100 is sealed by welding the lid 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 plate, a negative electrode plate, and a separator, and is a member that can store electricity. The detailed configuration of the electrode body 400 will be described later with reference to FIG.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 400 via the positive electrode current collector 120. The negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 400 through the negative electrode current collector 130. 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 a metal or the like having conductivity 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 via an insulating packing (not shown).

  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 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.

  Specifically, the positive electrode current collector 120 and the negative electrode current collector 130 are fixed to the lid 110. The positive electrode current collector 120 is bonded to the positive electrode side end of the electrode body 400, and the negative electrode current collector 130 is bonded to the negative electrode side end of the electrode body 400. 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 included in the electricity storage device 10 configured as described above will be described with reference to FIG.

  FIG. 3 is a perspective view illustrating a schematic configuration of the electrode body 400 according to the embodiment. In FIG. 3, elements such as electrode plates stacked and wound are partially developed and illustrated. 3 represents the winding axis of the electrode body 400. The alternate long and short dash line with the symbol W in FIG. The winding axis W is a virtual axis serving as a central axis when winding the electrode plate or the like, and is a straight line parallel to the X axis passing through the center of the electrode body 400 in the present embodiment.

  The electrode body 400 is an example of an electrode body having a positive electrode plate 410 and a negative electrode plate 420. In the present embodiment, as shown in FIG. 3, electrode body 400 is formed by laminating and winding separator 450, negative electrode plate 420, separator 430, and positive electrode plate 410 in this order. Has been. As shown in FIG. 3, the electrode body 400 has a flat shape in a direction orthogonal to the winding axis W (in the present embodiment, the Z-axis direction). That is, when viewed from the direction of the winding axis W, the electrode body 400 has an oval shape as a whole, the oval straight portion is flat, and the oval curved portion is curved. Become. For this reason, the electrode body 400 has a pair of flat portions 441 facing each other and a pair of curved portions 442 facing each other. Specifically, the pair of flat portions 441 are portions facing each other in the Z-axis direction with the winding axis W interposed therebetween. Further, the pair of curved portions 442 are portions facing each other in the Y-axis direction with the winding axis W interposed therebetween.

  In the present embodiment, the positive electrode plate 410 is obtained by forming a positive electrode mixture layer 414 containing a positive electrode active material on the surface of a long strip-shaped metal foil (positive electrode base material layer 411) made of aluminum. The negative electrode plate 420 is obtained by forming a negative electrode mixture layer 424 containing a negative electrode active material on the surface of a long metal foil (negative electrode base material layer 421) made of copper. Examples of the positive electrode active material and the negative electrode active material will be described later.

  In the present embodiment, separators 430 and 450 have a microporous sheet made of resin as a base material.

  In the electrode body 400 configured as described above, more specifically, the positive electrode plate 410 and the negative electrode plate 420 are wound with a shift in the direction of the winding axis W via the separator 430 or 450. And the positive electrode plate 410 and the negative electrode plate 420 have the active material uncoated part which is a part in which the active material is not coated of the base material layer in the edge part of each shifted direction.

  Specifically, the positive electrode plate 410 has an active material uncoated portion 411a that is not coated with the positive electrode active material at one end in the direction of the winding axis W (the end on the plus side in the X-axis direction in FIG. 3). Have. Further, the negative electrode plate 420 has an active material uncoated portion 421a on which the negative electrode active material is not applied at the other end in the direction of the winding axis W (the end on the minus side in the X-axis direction in FIG. 3). ing.

  That is, the positive electrode side end is formed by the exposed metal foil (active material uncoated portion 411a) layer of the positive electrode plate 410, and the exposed metal foil (active material uncoated portion 421a) layer of the negative electrode plate 420 is formed. A negative electrode side end is formed. The positive electrode side end is bonded to the positive electrode current collector 120, and the negative electrode side end is bonded to the negative electrode current collector 130. In the present embodiment, ultrasonic bonding is adopted as the bonding technique. In addition, as a technique for joining the electrode body 400 to the positive electrode current collector 120 and the negative electrode current collector 130, a technique such as resistance welding or clinch joining may be employed in addition to ultrasonic joining. Further, the number of electrode bodies 400 included in the electricity storage element 10 is not limited to 1, and may be 2 or more.

  In the electrode body 400 configured as described above, the positive electrode plate 410 has an insulating layer 415 formed in a region including the boundary between the positive electrode mixture layer 414 and the active material uncoated portion 411a. The insulating layer 415 contains a binder and particles such as inorganic particles. In other words, the positive electrode plate 410 includes the insulating layer 415 disposed so as to straddle the positive electrode base material layer 411 and the positive electrode composite material layer 414, thereby reliably preventing a short circuit between the positive electrode plate 410 and the negative electrode plate 420. Has been improved. Hereinafter, the insulating layer 415 and the structure around it will be described with reference to FIGS.

  FIG. 4 is a cross-sectional view illustrating a schematic configuration of the electrode body 400 according to the embodiment. Specifically, FIG. 4 shows a part of the positive electrode side of the electrode body 400 in the IV-IV cross section of FIG. FIG. 5 is a diagram illustrating a cross-sectional shape example of the positive electrode mixture layer 414 and the insulating layer 415 according to the embodiment, and FIG. 6 illustrates a surface shape of the first region 415a of the insulating layer 415 according to the embodiment. It is an enlarged view.

  As shown in FIGS. 4 and 5, the power storage device 10 according to the present embodiment includes an electrode body 400 having a positive electrode plate 410 and a negative electrode plate 420. The positive electrode plate 410 includes a conductive positive electrode base material layer 411, a positive electrode mixture layer 414 formed on the positive electrode base material layer 411, and at least a part including an edge of the positive electrode mixture layer 414. And an insulating layer 415 continuously formed on the edge portion 414a and the positive electrode base material layer 411.

  Thus, in this embodiment, a part of the positive electrode base material layer 411 protruding from the positive electrode mixture layer 414 (active material uncoated portion 411a) and the edge portion of the positive electrode mixture layer 414 are continuously provided. Then, an insulating layer 415 is formed so as to cover it. As a result, as shown in FIG. 4, the possibility of electrical contact between the active material uncoated part 411 a and the negative electrode plate 420 having portions overlapping each other in the thickness direction (Z-axis direction) is reduced. That is, a short circuit between the positive electrode plate 410 and the negative electrode plate 420 is more reliably prevented.

  In addition, since the insulating layer 415 is formed so that a part of the insulating layer 415 overlaps the edge of the positive electrode mixture layer 414, the insulating layer 415 is opened with a gap between the positive electrode mixture layer 414. A process requiring high accuracy such as adjoining each other is unnecessary.

  In addition, in the insulating layer 415, a region covering the active material uncoated portion 411a is referred to as a first region 415a, and a region covering the edge portion 414a is referred to as a second region 415b.

  Here, as shown in FIG. 6, a plurality of groove portions 4151 are formed on the surface of the first region 415a. The groove portion 4151 is a fine crack, and may have a branched shape, a single shape, or a shape in which a plurality of groove portions 4151 intersect each other. Further, the length of the groove 4151 may be arbitrary. The groove portion 4151 may not be exposed on the surface of the first region 415a, and may be formed so as to be partially or wholly embedded in the insulating layer 415 forming the first region 415a. Thus, since the groove portion 4151 is formed in the first region 415a, the thickness of the insulating layer 415 in the portion where the groove portion 4151 exists is the thickness of the insulating layer 415 in the portion where the groove portion 4151 does not exist (other portions). Thinner. That is, the insulating layer 415 in the portion where the groove portion 4151 is provided is more flexible than the other portion, and has a characteristic of being easily deformed following the positive electrode base material layer 411. That is, the part including the groove 4151 in the insulating layer 415 is a flexible part 419 that is more flexible than the other part. Specifically, a portion including the groove portion 4151 in a predetermined region in the insulating layer 415 is the flexible portion 419. On the other hand, a portion not including the groove 4151 in the predetermined region in the insulating layer 415 is “another portion”. Here, the predetermined region only needs to be within a range in which the presence of the groove portion 4151 can exhibit more flexibility than other portions as a whole region.

  Here, each of the positive electrode mixture layer 414 and the insulating layer 415 according to this embodiment contains a binder and particles.

As the positive electrode active material contained as the active material particles in the positive electrode mixture layer 414, for example, a composite oxide (Li _x CoO ₂ , Li represented by Li _x MO _y (M represents at least one kind of transition metal) is used. _{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 (1-y-z) O 2, Li x Ni y Mn _(2-y) O ₄ or the like) or Li _w Me _x (XO _y ) _z (Me represents at least one transition metal, and X represents, for example, P, Si, B, 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.) Can be selected. 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-based materials, pseudographite-structured carbonaceous materials, and the like are exemplified, but not limited thereto. Moreover, these compounds may be used independently and may mix and use 2 or more types.

The particles contained in the insulating layer 415 are inorganic particles, for example. Examples of the inorganic particles include alumina, silica, zirconia, titania, magnesia, ceria, yttria, zinc oxide, iron oxide, barium titanium oxide, oxides such as alumina-silica composite oxide, silicon nitride, titanium nitride, Boron nitride, nitrides such as aluminum nitride, poorly soluble ion crystals such as calcium fluoride, barium fluoride, barium sulfate, covalent bonds such as silicon and diamond, silicon carbide, calcium carbonate, aluminum sulfate, aluminum hydroxide, Potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amicite, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate, boehmite, apatite, Light, 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 particles contained in the insulating layer 415 may be organic particles.

  The binder contained in the insulating layer 415 is an aqueous or non-aqueous binder, and the binder contained in the positive electrode mixture layer 414 is, for example, a binder having the same polarity as the binder contained in the insulating layer 415. For example, when the insulating layer 415 contains a water-based binder, the positive electrode mixture layer 414 also contains a water-based binder. When the insulating layer 415 contains a non-aqueous binder, the positive electrode mixture layer 414 also contains a non-aqueous binder.

Here, the aqueous binder is a binder that is dispersed or dissolved in water. As the aqueous binder, a water-soluble binder (aqueous 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, a cross-linked product of chitosan, and the like.

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

  In this embodiment, the insulating layer 415 is provided on the positive electrode plate 410, but the negative electrode plate 420 may be provided with the insulating layer 415 in addition to or instead of the positive electrode plate 410. Good.

The negative electrode mixture layer 424 formed on the negative electrode base material layer 421 in the negative electrode plate 420 contains active material particles and a binder. Examples of the negative electrode active material contained in the negative electrode mixture layer 424 as active material particles include lithium metal, lithium alloys (lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood). Alloys containing lithium metal such as alloys), alloys capable of occluding and releasing lithium, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), metal oxides , Lithium metal oxides (such as Li ₄ Ti ₅ O ₁₂ ), and polyphosphoric acid compounds. 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 ratios.

  As the binder contained in the negative electrode mixture layer 424, the same binder as that used for the positive electrode mixture layer 414 can be employed.

  Next, a method for forming the groove 4151 in the insulating layer 415 in the manufacturing process of the electrode body 400 having the above configuration will be described.

  First, the positive electrode base material layer 411 in which the positive electrode mixture layer 414 is laminated is prepared. And the binder and particle | grains which comprise the insulating layer 415 are included with respect to the edge part 414a which is a part including the edge of the positive electrode compound material layer 414 in the positive electrode base material layer 411, and the positive electrode base material layer 411. Apply insulating paste. After the application, it is desirable that the region where the groove 4151 is formed (the region corresponding to the first region 415a) has an insulating paste thickness of 10 μm or more. This is because a plurality of groove portions 4151 are easily formed when the thickness of the insulating paste is 10 μm or more. Then, the insulating layer 415 having a plurality of irregular grooves 4151 is obtained by drying the applied insulating paste.

  Note that other forming methods of the groove portion 4151 include a mask method and a cutting method.

  The mask method is a method in which a groove 4151 is formed by previously forming a mask having a pattern of the groove 4151 at a position where the groove 4151 is formed, and applying an insulating paste and then removing the mask. The cutting method is a method of forming the groove portion 4151 by cutting an insulating layer that has been cured after application. With these masking and cutting methods, the pattern and shape of the groove 4151 can be controlled, so that the groove 4151 corresponding to the characteristics of the electrode body 400 can be formed.

  As described above, according to the present embodiment, the insulating layer 415 includes the flexible portion 419 that is more flexible than the other portions. The layer 411 has a characteristic of being easily deformed following the layer 411. Thereby, even if a physical load is applied to the insulating layer 415, it is possible to prevent the insulating layer 415 from dropping from the positive electrode base material layer 411. Therefore, stable insulation can be ensured.

  In particular, at the time of manufacturing, when the positive electrode current collector 120 is bonded to the positive electrode side end portion of the positive electrode plate 410, the positive electrode side end portion is bundled and pressed. As a result, a physical load acts on the insulating layer 415. However, since the insulating layer 415 is difficult to drop off as a whole by the flexible portion 419, it is possible to prevent the insulating layer 415 from dropping off even during manufacturing. Can do.

  Further, since the flexible portion 419 is a portion including the groove portion 4151 formed in the insulating layer 415, the groove portion 4151 can be easily formed by simply drying the insulating paste at the time of manufacture, and thus the flexible portion 419 can be easily formed. Can be formed.

  Moreover, since the groove part 4151 is formed in the 1st area | region 415a which covers the active material uncoated part 411a among the insulating layers 415, the 1st area | region 415a can be made flexible. Note that the groove 4151 may be formed also in the second region 415b of the insulating layer 415. Thereby, the whole insulating layer 415 becomes flexible, and the drop-off of the whole insulating layer 415 can be suppressed.

  In addition, since the insulating layer 415 is continuously formed on the edge portion 414a of the positive electrode mixture layer 414 from the positive electrode base material layer 411, even if the mixture layer 414 expands and contracts due to charge and discharge, The stress generated between the insulating layer 415 and the positive electrode mixture layer 414 can be relieved.

(Example)
Next, examples of power storage element 10 according to the present embodiment will be described.

  In this embodiment, the ratio between the particles forming the insulating layer and the binder and the thickness of the insulating layer 415 will be specifically described.

  FIG. 7 is a table showing whether or not the insulating layer is dropped at each ratio by changing the ratio between the particles forming the insulating layer and the binder according to the example.

Here, in the two types of insulating layers having different contained particles, the ratio of the binder is varied. The same binder is used in the two types of insulating layers. The particles A are Al ₂ O ₃ having an average particle diameter (D ₅₀ ): 0.7 ± 0.16 μm and a specific surface area: 4.5 ± 0.5 m ² / g. The particles B are Al ₂ O ₃ having an average particle diameter (D ₅₀ ): about 0.015 μm and a specific surface area: 100 ± 15 m ² / g. Binder C is PVdF having a number average molecular weight of about 500,000. The thickness of each insulating layer is 25 μm. In FIG. 7, “◯” indicates that the insulating layer has not been dropped, and “X” indicates that the insulating layer has been dropped. In FIG. 7, “-” does not acquire data.

  As can be seen from FIG. 7, in the insulating layer using the particles B, there are ratios (25%, 30%, and 35%) at which dropping occurs. However, the insulating layer using the particles A does not drop out even at the same ratio. For this reason, the insulating layer using the particles A has a characteristic that it is less likely to fall off.

  FIG. 8 is a table showing whether or not the insulating layer is dropped at each thickness by varying the thickness of the insulating layer according to the example.

  Here, an insulating layer containing particles A and a binder C, and an insulating layer having a binder ratio of 10% is used. As can be seen from FIG. 8, the insulating layer does not fall off when the thickness is in the range of 5 μm to 55 μm, and the insulating layer falls off when the thickness is in the range of 60 μm to 70 μm. For this reason, when using the insulating layer containing the particle | grains A and the binder C, it is good to set thickness to less than 60 micrometers. As described above, if the groove is formed in the insulating layer by drying, it is desirable that the thickness of the insulating layer is 10 μm or more. Therefore, a preferable range for the thickness of the insulating layer is 10 μm or more and less than 60 μm. It is.

(Other embodiments)
The power storage element according to the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiment. Unless it deviates from the gist of the present invention, various modifications conceived by those skilled in the art have been applied to the above-described embodiments, or forms constructed by combining a plurality of the constituent elements described above are within the scope of the present invention. include.

  For example, in the above embodiment, as shown in FIG. 4 and the like, the insulating layer 415 covers only the edge portion 414a on the active material uncoated portion 411a side with respect to the positive electrode mixture layer 414. The layer 415 may cover the entire area (including substantially the entire area) of the positive electrode mixture layer 414. Thereby, the certainty of short circuit prevention with the negative electrode plate 420 improves more in the whole area | region of the positive mix layer 414. FIG. That is, the insulating layer 415 is continuously formed on at least a part of the edge including the edge of the positive electrode (or negative electrode) composite material layer and on the positive electrode (or negative electrode) base material layer. It only has to be.

  Here, even when the insulating layer 415 </ b> A covers the entire area of the positive electrode mixture layer 414, it is sufficient that a flexible portion is provided in at least a part of the insulating layer 415 </ b> A.

  FIG. 9 is a cross-sectional view illustrating a case where the insulating layer 415A covers the entire area of the positive electrode mixture layer 414. Specifically, FIG. 9 corresponds to FIG.

  As shown in FIG. 9, the flexible part 419a should just be provided in at least one part of the area | region corresponding to the flat part 441 of the electrode body 400 in 415A of insulating layers. As described above, when the positive electrode current collector 120 is bonded to the positive electrode side end of the positive electrode plate 410, the positive electrode side end is bundled and pressed. At this time, since the part corresponding to the flat part 441 is mainly bundled, the load acting on the flat part 441 becomes larger than that of the bending part 442. That is, the flat portion 441 is a condition that the insulating layer is more easily dropped than the curved portion 442. However, if the flexible portion 419a is provided in a region corresponding to the flat portion 441 in the insulating layer 415A, the insulating layer 415A can be prevented from falling off.

  In addition, the region where the positive electrode current collector 120 is bonded and the vicinity thereof are sites where the load acts most during bonding. For this reason, in the region corresponding to the flat portion 441 in the insulating layer, the flexible portion is provided in the region where the positive electrode current collector 120 is joined or in the vicinity thereof, thereby reliably preventing the insulating layer from falling off. In addition, it is preferable.

  In the above embodiment, the positive electrode mixture layer 414 includes a binder having the same polarity as that of the insulating layer 415. However, the positive electrode mixture layer 414 may include a binder having a polarity different from that of the insulating layer 415. Good.

  In addition, the electrode body included in the electricity storage element 10 does not have to be a wound type. The power storage element 10 may include a stacked electrode body in which flat plate plates are stacked, for example. Moreover, the electrical storage element 10 may be provided with the electrode body which has a structure which laminated | stacked the elongate strip | belt-shaped electrode plate on the bellows shape by repeating a mountain fold and a valley fold, for example. In either case, the positive electrode plate and the negative electrode plate have a structure in which the positive electrode plate and the negative electrode plate are laminated via the separator, so that the positive electrode plate or the negative electrode plate covers the active material uncoated part and the edge part of the composite material layer. By including the insulating layer, the certainty of preventing a short circuit between the positive electrode plate and the negative electrode plate is improved. Then, by providing the flexible portion in the insulating layer, it is possible to suppress the falling off of the insulating layer as described above, and it is possible to ensure stable insulation.

  Moreover, you may use a bag-shaped laminate film for the container which accommodates an electrode body.

  Further, the extending direction of the groove portion 4151 is not limited to the vertical direction and the horizontal direction.

  FIG. 10 is an enlarged view showing a case where the groove portion 4151 extends in the vertical direction, and FIG. 11 is an enlarged view showing a case where the groove portion 4151 extends in the horizontal direction. 10 and 11 correspond to FIG. Here, the vertical direction is a direction parallel to the winding axis direction of the electrode body, and the horizontal direction is a direction orthogonal to the vertical direction. As shown in FIG. 10, all the groove portions 4151 may extend along the vertical direction. Moreover, as shown in FIG. 11, all the groove parts 4151 may be extended in the horizontal direction. In any case of FIGS. 6, 10, and 11, the effect of suppressing the falling off of the insulating layer 415 can be obtained.

  Moreover, in the said embodiment, the part containing the groove part 4151 was illustrated and demonstrated as an example of the flexible part 419. However, the flexible portion may have any form as long as it is more flexible than other portions of the insulating layer 415. Examples of the flexible part other than the groove part 4151 include a configuration in which the entire region (flexible region) to be made flexible in the insulating layer is made thinner than the other regions, and the flexible region is more flexible than the other regions. The form comprised by is mentioned.

  In addition, embodiments constructed by arbitrarily combining the configurations described in the above embodiments are also included in the scope of the present invention.

  In addition, the present invention can be realized not only as the power storage element described above but also as the 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 present invention is applicable to power storage elements such as lithium ion secondary batteries.

DESCRIPTION OF SYMBOLS 10 Storage element 100 Container 110 Cover body 111 Main body 120 Positive electrode collector 130 Negative electrode collector 200 Positive electrode terminal 300 Negative electrode terminal 400 Electrode body 410 Positive electrode plate (electrode plate)
411 Positive electrode base material layer 411a Active material uncoated portion 414 Positive electrode mixture layer 414a Edge portions 415, 415A Insulating layer 415a First region 415b Second region 419, 419a Flexible portion 420 Negative electrode plate (electrode plate)
421 Negative electrode base material layer 421a Active material uncoated portion 424 Negative electrode composite material layer 430, 450 Separator 441 Flat portion 442 Curved portion 4151 Groove portion

Claims (5)

An electrical storage element comprising an electrode body having an electrode plate,
The electrode plate is
A conductive substrate layer;
A composite material layer formed on the base material layer;
And at least a part has an insulating layer formed on the base material layer,
The insulating layer has a flexible portion that is more flexible than other portions. The power storage element according to claim 1, wherein the flexible portion is a portion including a groove formed in the insulating layer. The insulating layer is provided continuously with respect to the entire mixture layer,
The power storage element according to claim 1, wherein the flexible portion is provided in at least a part of a region corresponding to the flat portion of the electrode body in the insulating layer. The electric storage element according to claim 1, wherein the insulating layer is continuously formed on an edge portion that is a portion including an edge of the composite material layer. The power storage element according to claim 4, wherein the flexible portion is provided in at least a part of a region corresponding to the edge portion and the base material layer in the insulating layer.

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