Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/04—Construction or manufacture in general
  • H01M10/0463—Cells or batteries with horizontal or inclined electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
  • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/04—Construction or manufacture in general
  • H01M10/0413—Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
  • H01M50/461—Separators, membranes or diaphragms characterised by their combination with electrodes with adhesive layers between electrodes and separators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/058—Construction or manufacture
  • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

• the present invention relates to a bag-packed positive electrode plate, a layered electrode assembly, and an energy storage device.
• a chargeable and dischargeable energy storage device has been used in various equipment such as a mobile phone or an electric vehicle.
• the energy storage device includes a layered electrode assembly which is formed by alternately stacking a positive electrode plate having a surface on which a positive active material layer is formed and a negative electrode plate having a surface on which a negative active material layer is formed with a separator having electric insulation property sandwiched between the positive electrode plate and the negative electrode plate.
• a separator having electric insulation property sandwiched between the positive electrode plate and the negative electrode plate.
• a layered electrode assembly which can suppress mixing of metal species which generate metal ions capable of forming a precipitation on an electrolyte in the vicinity of the positive electrode plate and can suppress electrodeposition caused by contacting of metal ions with a negative electrode using a bag-packed electrode plate which is formed into a bag shape by welding outer peripheries of a pair of separators which sandwiches the positive electrode plate or the negative electrode plate therebetween to each other.
• a welded portion of the separators does not contribute to charging and discharging and hence, when a space in the inside of an energy storage device is occupied only by the welded portion of the separators, there may be a possibility that such a configuration obstructs the increase of energy density of the energy storage device.
• the positive electrode plate projects from the negative electrode plate as viewed in a plan view, an electric current is concentrated on an end portion of the negative electrode plate so that electrodeposition is locally accelerated and hence, it is preferable that the positive electrode plate be disposed so as not to project from the negative electrode plate as viewed in a plan view. Accordingly, by using a layered electrode assembly formed by stacking a bag-packed positive electrode plate and a negative electrode plate which is not bag-packed, the space efficiency can be enhanced thus increasing energy density of the energy storage device.
• an energy storage device there may be a case which is not a normal in-use case of the energy storage device, for example, a case where an object other than the energy storage device is pressed to the energy storage device (for example, an automobile on which the energy storage device is mounted being involved in a traffic accident).
• an object other than the energy storage device is pressed to the energy storage device (for example, an automobile on which the energy storage device is mounted being involved in a traffic accident).
• the object pierces a layered electrode assembly so that a positive electrode plate and a negative electrode plate are short-circuited thus giving rise to a sharp increase of a temperature in the layered electrode assembly.
• JP-A-2016- 190499 discloses a technique where an object other than an energy storage device minimally penetrates a separator with the use of a separator which is formed by stacking a porous layer containing inorganic fine particles and a binder resin in a resin film.
• a separator which is formed by stacking a porous layer containing inorganic fine particles and a binder resin in a resin film.
• JP-A-2015-213073 discloses a method where a layer which contains inorganic fine particles and a binder resin is disposed on a non-coated portion of a positive electrode. With such a method, even when a foreign substance penetrates a separator which opposedly faces the non-coated portion of the positive electrode, an energy storage device can ensure safety. However, there exists a drawback that coating of the layer which contains the inorganic fine particles and the binder resin to the positive electrode non-coated portion makes the method complicated thus pushing up a manufacturing cost of an energy storage device.
• Patent Document l JP-A-2016- 190499
• Inventors of the present invention have studied the generation of heat when an object other than an energy storage device penetrates a layered electrode assembly. As a result of such studies, the inventors of the present invention have confirmed that the generation of heat is relatively liable to become large in a case where the object other than the energy storage device penetrates a region of an electrode plate on which an active material is not stacked (specifically a tab portion which extends for connecting the electrode plate to an electrode terminal of the energy storage device) compared to a case where the object other than the energy storage device penetrates a region of an electrode plate on which the active material is stacked.
• a bag-packed positive electrode plate includes : a positive electrode plate having a tab; and a pair of separators which sandwiches the positive electrode plate
• each of the separators has ⁇ a resin layer! a heat resistant layer stacked on the resin layer! and an adhesive layer stacked on a surface of the heat resistant layer which opposedly faces the positive electrode plate, and the adhesive layers of the pair of separators are adhered to the tab.
• the adhesive layers of the pair of separators are adhered to the tab and hence, it is possible to suppress the generation of heat when an object other than an energy storage device penetrates the tab.
• Fig. 1 is a schematic exploded perspective view showing a
• Fig. 2 is a schematic partially enlarged cross-sectional view of a layered electrode assembly of the energy storage device shown in Fig. 1.
• Fig. 3 is a schematic plan view of a bag-packed positive electrode plate of the energy storage device shown in Fig. 1.
• a bag-packed positive electrode plate includes : a positive electrode plate having a tab; and a pair of separators which sandwiches the positive electrode plate
• each of the separators has ⁇ a resin layer! a heat resistant layer stacked on the resin layer! and an adhesive layer stacked on a surface of the heat resistant layer which opposedly faces the positive electrode plate, and the adhesive layers of the pair of separators are adhered to the tab.
• the separator has the resin layer, the heat resistant layer and the adhesive layer, and the adhesive layer is adhered to the tab of the positive electrode plate. Accordingly, it is considered that even when an object other than the energy storage device penetrates the tab, a state where the separator is adhered to the tab can be maintained and hence, a contact area between a negative electrode plate and the tab can be decreased whereby a short circuit current between the positive electrode plate and the negative electrode plate can be reduced thus suppressing the generation of heat.
• an average distance between an active material stacked region of the positive electrode plate and an adhered region of the adhesive layer to the tab is preferably set to 500 ⁇ or below, and more preferably set to 300 ⁇ or below.
• the adhesive layer be formed of a mixed material which contains : particles including an electrolyte solution and exhibiting ion conductivity! and a binder.
• a layered electrode assembly includes : a plurality of the bag-packed positive electrode plates! and a plurality of negative electrode plates, wherein the bag-packed positive electrode plate and the negative electrode plate are alternately stacked with each other.
• the layered electrode assembly includes the bag- packed positive electrode plates and hence, the generation of heat when an object other than the energy storage device penetrates the tab can be suppressed.
• an adhered region of the adhesive layer to the tab extend to the outside of the negative electrode plate as viewed in a plan view.
• the tab is further minimally brought into contact with the negative electrode plate when an object other than the energy storage device penetrates the tab thus suppressing the generation of heat with more certainty.
• An energy storage device includes : the layered electrode assembly! and an outer case which accommodates the layered electrode assembly therein.
• the energy storage device can suppress the generation of heat when an object other than the energy storage device penetrates the tab.
• Fig. 1 shows an energy storage device according to one embodiment of the present invention.
• the energy storage device includes a layered electrode assembly 1, and an outer case 2 which accommodates the layered electrode assembly 1 therein.
• An electrolyte (electrolyte solution) is filled in the outer case 2.
• the energy storage device further includes a positive electrode terminal 3 and a negative electrode terminal 4 which project from the outer case 2 and are electrically connected to the layered electrode assembly 1.
• the layered electrode assembly 1 includes a plurality of bag-packed positive electrode plates 5 and a plurality of negative electrode plates 6, wherein the bag-packed positive electrode plate 5 and the negative electrode plate 6 are alternately stacked with each other.
• Each bag-packed positive electrode plate 5 includes a positive electrode plate 7, and a pair of separators 8 which sandwiches the positive electrode plate 7 therebetween.
• the pair of separators 8 may be two sheets opposedly facing each other, or may be formed by folding one sheet in two.
• a width of the bag-packed positive electrode plate 5 be set equal to or below a width of the negative electrode plate 6.
• a width of the separator 8 having an approximately rectangular planar shape is set equal to or below a width of the negative electrode plate 6 having an
• a whole surface of the positive electrode plate 7 held inside the separator 8 as viewed in a plan view is made to opposedly face the negative electrode plate 6 without projecting from the negative electrode plate 6 as viewed in a plan view. That is, the positive electrode plate 7 is embraced within a projection region of the negative electrode plate 6. Accordingly, in the layered electrode assembly 1 and the energy storage device, there is no possibility that a current density is increased on an outer peripheral portion of the negative electrode plate 6 so that electrodeposition is locally
• a lower limit of the difference between a width of the bag-packed positive electrode plate 5 and a width of the negative electrode plate 6 is preferably set to 0 mm, and an upper limit of the difference between the width of the bag- packed positive electrode plate 5 and the width of the negative electrode plate 6 is preferably set to 2 mm, and more preferably set to 1.0 mm.
• the difference between the width of the bag-packed positive electrode plate 5 and the width of the negative electrode plate 6 is set to the above-mentioned upper limit or below, it is possible to prevent the difference in area between the positive electrode plate 7 and the negative electrode plate 6 from increasing unnecessarily thus increasing energy density of the layered electrode assembly 1 and energy density of the energy storage device.
• the positive electrode plate 7 can be relatively easily positioned with respect to the negative electrode plate 6. Accordingly, in the layered electrode assembly 1, even when a ratio of an area of the positive electrode plate 7 with respect to an area of the negative electrode plate 6 is relatively increased, electrodeposition on the outer edge portion of the negative electrode plate 6 is not accelerated and hence, energy density can be relatively increased.
• the positive electrode plate 7 includes ⁇ a foil-like or sheet-like positive electrode current collector 9 having conductivity! and a positive active material layer 10 which is stacked on a surface of the positive electrode current collector 9.
• the positive electrode plate 7 is configured to include an active material stacked region having a rectangular shape as viewed in a plan view where the positive active material layer 10 is stacked on a surface of the positive electrode current collector 9! and a positive electrode tab 11 which extends from the active material stacked region in a strip shape having a width smaller than a width of the active material stacked region and is connected to the positive electrode terminal 3.
• a metal material such as aluminum, copper, iron or nickel, or an alloy of such metal materials is used.
• aluminum, an aluminum alloy, copper, and a copper alloy are preferably used, and aluminum and an aluminum alloy are more preferably used.
• the configuration of the positive electrode current collector 9, a foil, a vapor deposition film and the like can be named.
• the positive electrode current collector 9 is preferably formed of a foil. That is, the positive current collector 9 is preferably made of an aluminum foil.
• A1085P, A3003P prescribed in JIS-H4000 (2014) or the like can be exemplified.
• a lower limit of an average thickness of the positive electrode current collector 9 is preferably set to 5 ⁇ , and more preferably set to 10 ⁇ .
• an upper limit of the average thickness of the positive electrode current collector 9 is preferably set to 50 ⁇ , and more preferably set to 40 ⁇ .
• the positive active material layer 10 is made of a so-called positive electrode mixture containing a positive active material.
• the positive electrode mixture which forms the positive active material layer 10 contains arbitrary components such as a conductive agent, a binder, a thickening agent, a filler and the like when necessary.
• a composite oxide expressed by Li x MO y (M indicating at least one kind of transition metal) (Li x Co02, Li x Ni02, Li x Mn204, Li x Mn03, Li x Ni a Co(i- a )02, Li x Ni a MnpCoa- a -p)O2, Li x Ni a Mn(2-a)04 or the like), or a polyanion compound expressed by Li x MO y (M indicating at least one kind of transition metal) (Li x Co02, Li x Ni02, Li x Mn204, Li x Mn03, Li x Ni a Co(i- a )02, Li x Ni a MnpCoa- a -p)O2, Li x Ni a Mn(2-a)04 or the like), or a polyanion compound expressed by Li x MO y (M indicating at least one kind of transition metal) (Li x Co02, Li x Ni02,
• Li w Me x (XOy)z (Me indicating at least one kind of transition metal, X being P, Si, B, V or the like, for example)
• LiFeP0 4 , LiMnP0 4 , LiNiP0 4 , L1C0PO4, Li3V2(P0 4 )3, Li2MnSi0 4 , Li2CoPO 4 F or the like can be named.
• An element or a polyanion in these compounds may be partially replaced with other elements or other anion species.
• one kind of these compounds may be used singly or these compounds may be used in a state where two or more kinds of compounds are mixed.
• the crystal structure of the positive active material be a layered structure or a spinel structure.
• a lower limit of a content of the positive active material in the positive active material layer 10 is preferably set to 50 mass%, and more preferably set to 70 mass%, and still further preferably set to 80 mass%.
• an upper limit of the content of the positive active material in the positive active material layer 10 is preferably set to 99 mass%, and more preferably set to 94 mass%.
• the conductive agent is not particularly limited provided that the conductive agent is made of a conductive material which does not adversely affect battery performance.
• a conductive agent natural or artificial graphite, carbon black such as furnace black, acetylene black and Ketjen black, metal, conductive ceramics and the like can be named.
• a shape of the conductive agent a powdery form, a fibrous form and the like can be named.
• a lower limit of a content of the conductive agent in the positive active material layer 10 is preferably set to 0.1 mass%, and more preferably set to 0.5 mass%.
• an upper limit of the content of the conductive agent is preferably set to 10mass%, and more preferably set to 5 mass%.
• a fluororesin As a material of the binder, for example, a fluororesin
• thermoplastic resin such as polyethylene, polypropylene and polyimide, elastomer such as ethylene-propylene-diene rubber (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber and the like, for example, polysaccharide polymer and the like can be named.
• EPDM ethylene-propylene-diene rubber
• SBR styrene-butadiene rubber
• fluororubber for example, polysaccharide polymer and the like can be named.
• a lower limit of a content of the binder in the positive active material layer 10 is preferably set to 1 mass%, and more preferably set to 2 mass%.
• an upper limit of the content of the binder is preferably set to 10 mass%, and more preferably set to 5 mass%.
• polysaccharide polymer such as carboxymethyl cellulose (CMC), methyl cellulose and the like can be named.
• CMC carboxymethyl cellulose
• the thickening agent has a functional group reactable with lithium, it is preferable to preliminarily deactivate the functional group by methylation or the like.
• a material of the filler is not particularly limited provided that the battery performance is not adversely affected by the material.
• a polyolefin such as polypropylene and polyethylene, silica, alumina, zeolite, glass, carbon and the like can be named.
• a lower limit of an average thickness of the positive active material layer 10 is preferably set to 10 ⁇ , and more preferably set to 20 ⁇ .
• an upper limit of the average thickness of the positive active material layer 10 is preferably set to 100 ⁇ , and more preferably set to 80 ⁇ .
• the separator 8 includes a sheet-like resin layer 12, a heat resistant layer 13 which is stacked on a surface of the resin layer 12 which opposedly faces the positive electrode plate 7, and an adhesive layer 14 which is stacked on a surface of the heat resistant layer 13 which opposedly faces the positive electrode plate 7.
• the adhesive layers 14 of the pair of separators 8 are adhered to each other outside the active material stacked region of the positive electrode plate 7 as viewed in a plan view (the adhered region of the separator 8 being indicated by hatching in Fig. 3).
• the adhesion of the adhesive layers 14 of the pair of separators 8 outside the active material stacked region of the positive electrode plate 7 may be performed continuously along an outer edge of the active material stacked region of the positive electrode plate 7.
• by performing the adhesion of the adhesive layers 14 intermittently pouring of an electrolyte solution to the separator 8 can be accelerated.
• the adhesive layer 14 of the separator 8 may be adhered to the positive active material layer 10. By adhering the adhesive layer 14 to the positive active material layer 10, it is possible to prevent the intrusion of foreign substances which generate metal ions between the positive electrode pate 7 and the separator 8 thus suppressing internal short-circuiting caused by electrodeposition of the layered electrode assembly 1.
• the adhesive layer 14 of the separator 8 is adhered to the positive electrode tab 11.
• the object other than the energy storage device penetrates the positive electrode tab 11 so that the positive electrode tab 11 is broken and a portion which is bent in a tongue shape or a burr-shape is formed and extends toward the negative electrode plate 6.
• the separator 8 is maintained in an adhered state to the surface of the broken positive electrode tab 11 is maintained and hence, a contact area between the positive electrode tab 11 and the negative electrode plate 6 is reduced.
• a short-circuit current between the positive electrode tab 11 and the negative electrode plate 6 is reduced thus suppressing the generation of heat caused by a short circuit current when the object other than the energy storage device penetrates the tab.
• the positive active material layer 10 has a relatively large
• an upper limit of an average distance D (see Fig. 2) between the active material stacked region of the positive electrode plate 7 and the adhered region of the adhesive layer 14 to the positive electrode tab 11 is preferably set to 500 ⁇ , more preferably set to 300 ⁇ , and further more preferably set to 200 ⁇ .
• the average distance D between the active material stacked region of the positive electrode plate 7 and the adhered region of the adhesive layer 14 to the positive electrode tab 11 is set to the above-mentioned upper limit or below, it is possible to effectively suppress the contact of the positive electrode tab 11 to the negative electrode plate 6 when an object other than the energy storage device penetrates the positive electrode tab 11.
• the resin layer 12 is formed of a porous resin film.
• the resin layer 12 As a main component of the resin layer 12, for example,
• polyethylene PE
• polypropylene PP
• ethylene-vinyl acetate copolymer ethylene-methylacrylate copolymer
• ethylene-ethyl acrylate copolymer ethylene-ethyl acrylate copolymer
• a polyolefin derivative such as chlorinated polyethylene
• polyolefin such as ethylene-propylene copolymer
• polyester such as polyethylene- telephthalate and copolyester
• main component means a component having a largest mass content.
• a lower limit of an average thickness of the resin layer 12 is preferably set to 5 ⁇ , and more preferably set to 10 ⁇ .
• an upper limit of the average thickness of the resin layer 12 is preferably set to 30 ⁇ , and more preferably set to 20 ⁇ .
• the heat resistant layer 13 is configured to contain a large number of inorganic particles, and a binder for connecting the inorganic particles to each other.
• alumina, silica, zirconia, titania, magnesia, ceria, yttria, an oxide such as a zinc oxide and an iron oxide, a nitride such as a silicon nitride, a titanium nitride and a boron nitride, silicon carbide, calcium carbonate, aluminum sulfate, aluminum hydroxide, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amesite, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate or the like can be named.
• alumina, silica and titania are particularly preferable.
• a lower limit of an average particle size of the inorganic particles contained in the heat resistant layer 13 is preferably set to 1 nm, and more preferably set to 7 nm.
• an upper limit of the average particle size of the inorganic particles is preferably set to 5 ⁇ , and more preferably set to 1 ⁇ .
• a fluororesin such as polyvinylidene fluoride
• fluororubber such as vinylidene fluoride- hexafluoropropylene-tetrafluoroethylene copolymer, styrene-butadiene copolymer, and hydride of styrene-butadiene copolymer, acrylonitrile- butadiene copolymer and hydride of acrylonitrile-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer and hydride of acrylonitrile- butadiene- styrene copolymer, synthetic rubber such as methacrylic ester- acrylic ester copolymer, styrene-acrylic ester copolymer, and acrylonitrile- acrylic ester copolymer, cellulose derivative such as carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and ammonium salt of carboxymethyl cellulose, polyether
• a lower limit of an average thickness of the heat resistant layer 13 is preferably set to 2 ⁇ , and more preferably set to 4 ⁇ .
• an upper limit of the average thickness of the heat resistant layer 13 is preferably set to 10 ⁇ , and more preferably set to 6 ⁇ .
• the adhesive layer 14 can be made of a material exhibiting ion conductivity and having adhesiveness.
• the adhesive layer 14 can be made of a mixed material containing particles which possess ion conductivity by including an electrolyte solution, and a binder which possesses adhesiveness. It is preferable that the adhesive layer 14 have continuous pores so as to allow a liquid and a gas to pass therethrough.
• a lower limit of an average thickness of the adhesive layer 14 is preferably set to 0.1 ⁇ , more preferably set to 0.2 ⁇ , and further more preferably set to 0.4 ⁇ .
• an upper limit of the average thickness of the adhesive layer 14 is preferably set to 5 ⁇ , more preferably set to 3 ⁇ , and further more preferably set to 1.2 ⁇ .
• the particles of the adhesive layer 14 which exhibits ion conductivity by including an electrolyte solution for example, an inorganic solid electrolyte, a pure solid polymer electrolyte, a gel polymer electrolyte and the like can be named.
• an electrolyte solution for example, an inorganic solid electrolyte, a pure solid polymer electrolyte, a gel polymer electrolyte and the like.
• the gel polymer electrolyte which can increase ion conductivity and is homogenous thus enabling the easy adjustment of a particle size is particularly
• the gel polymer electrolyte is a material which can facilitate handling thereof by turning an electrolyte solution into a gel state by polymer.
• a polymer which turns an electrolyte solution into a gel state for example, vinylidene fluoride-hexafluoropropylene copolymer,
• polymethylmethacrylic acid polyacrylonitrile and the like can be named.
• an organic electrolyte solution formed by dissolving a support electrolyte in an organic solvent is used.
• a lithium salt is preferably used.
• a lithium salt is not particularly limited, for example, LiPF 6 , LiAsFe, LiBF 4 , LiSbF 6 , LiAlCl 4 , LiC10 4 , CF 3 S0 3 Li, C 4 F 9 S0 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi, (CF 3 S0 2 ) 2 NLi, (C 2 F 5 S0 2 )NLi and the like can be named.
• LiPF6, LiC10 4 , CF3S0 3 Li which are easily dissolved in an organic solvent and exhibit a high dissociation degree are particularly preferably used.
• An organic solvent used in an electrolyte solution is not particularly limited provided that the organic solvent can dissolve a support electrolyte.
• carbonates such as a dimethyl carbonate (DMC), an ethylene carbonate (EC), a diethyl carbonate (DEC), a propylene carbonate (PC), a butylene carbonate (BC), and an methyl-ethyl carbonate (MEC), for example, esters such as ⁇ -butyrolactone and methyl formate, for example, ethers such as 1,2- dimethoxy- ethane and tetrahydrofuran, sulfur- containing compounds such as sulfolane and dimethylsulioxide and the like can be used singly or in combination of plural kinds of these materials.
• carbonates having a high dielectric constant and having a wide stable potential region are particularly preferably used.
• a lower limit of concentration of the support electrolyte in the electrolyte solution is preferably set to 1 mass%, and more preferably set to 5 mass%.
• an upper limit of the concentration of the support electrolyte in the electrolyte solution is preferably set to 30 mass%, and more preferably set to 20 mass%.
• a lower limit of an average particle size of the solid electrolyte particles is preferably set to 0.1 ⁇ , and more preferably set to 0.2 ⁇ .
• an upper limit of the average particle size of the solid electrolyte particles is preferably set to 2 ⁇ , and more preferably set to 1 ⁇ .
• a shape of the solid electrolyte particles a shape having small sphericity such as a rod shape, a conical shape, a plate shape, for example, is preferable so as to increase ion conductivity by accelerating contact between the solid electrolyte particles, for example.
• the binder As a binder in the adhesive layer 14, it is sufficient that the binder have adhesiveness to the solid electrolyte particles and the positive active material layer 10.
• a resin capable of being adhered to the positive active material layer 10 by being heated at a relatively low temperature, that is, a polymer material having a relatively low glass transition point and exhibiting adhesiveness is preferably used.
• a lower limit of the glass transition point of the binder is preferably set to -50°C, and more preferably set to -45°C.
• an upper limit of the glass transition point of the binder is preferably set to 80°C, and more preferably set to 45°C.
• an acrylic polymer and the like can be named.
• the acrylic polymer a nitrile -group - containing acrylic polymer which includes a monomer unit having a nitrile group and a (meth)acrylate acid ester monomer unit is preferably used.
• the monomer unit having a nitrile group is a structural unit obtained by polymerizing acrylonitrile, methacrylonitrile or the like, for example, and a (meth)acrylate acid ester monomer unit is a monomer unit derived from a compound expressed by (in the formula, R 1 indicating a hydrogen atom or a methyl group, and R 2 indicating an alkyl group or a cycloalkyl group).
• the nitrile group containing acrylic polymer may contain an ethylenic unsaturated acid monomer unit obtained by
• nitrile group containing acrylic polymer may be formed in a cross-linking manner.
• a lower limit of a ratio of the solid electrolyte particles in the adhesive layer 14 is preferably set to 70 mass%, and more preferably set to 80 mass%.
• an upper limit of the ratio of the solid electrolyte particles in the adhesive layer 14 is preferably set to 95 mass%, and more preferably set to 90 mass%.
• the ratio of the solid electrolyte particles in the adhesive layer 14 is set to the above-mentioned upper limit or below, it is possible to impart sufficient adhesiveness to the adhesive layer 14 while setting a ratio of the binder to the adhesive layer 14 to a fixed value or more relatively.
• the bag-packed positive electrode plate 5 can be manufactured by a method including the steps ⁇ ' - sandwiching the positive electrode plate 7 by the pair of separators 8 each having the resin layer 12, the heat resistant layer 13, and the adhesive layer 14 (stacking step); and sandwiching a layered product of the positive electrode plate 7 and the pair of separators 8 by a heating mold which is heated to a temperature lower than a melting point of the resin layer 12 (pressing step).
• the adhesive layers 14 of the separators 8 are respectively brought into contact with the positive electrode plate 7, and the positive electrode plate 7 and the pair of separators 8 are stacked to each other such that the separators 8 envelope the active material stacked region of the positive electrode plate 7 as viewed in a plan view.
• a pair of heating molds is heated to a
• the heating molds are configured to have a convex shape portion respectively such that, outside the active material stacked region of the positive electrode plate 7 as viewed in a plan view, the heating molds make the adhesive layers 14 adhere to adhesive layer 14 of the separator 8 which opposedly face each other and the positive electrode tab 11 by pressure bonding.
• the negative electrode plates 6 are stacked in the layered electrode assembly 1 without being bag-packed unlike the positive electrode plates 7.
• the negative electrode plate 6 includes ⁇ a foil-like or sheet-like negative electrode current collector 15 having conductivity! and a negative active material layer 16 which is stacked on a surface of the negative electrode current collector 15.
• the negative electrode plate 6 is configured to include : an active material stacked region having a rectangular shape as viewed in a plan view where the active material layer 12 is stacked on a surface of the negative electrode current collector 15; and a negative electrode tab 17 which extends from the active material stacked region in a strip shape having a width smaller than a width of the active material stacked region and is connected to the negative electrode terminal 4.
• the negative electrode current collector 15 can be formed substantially in the same manner as the above-mentioned positive electrode current collector 9, copper or a copper alloy is preferably used as a material for forming the negative electrode current collector 15. That is, a copper foil is preferably used as the negative electrode current collector 15 of the negative electrode plate 6. As a copper foil, a rolled copper foil, an electrolytic copper foil and the like can be exemplified.
• the negative active material layer 16 is made of a so-called negative electrode plate mixture containing a negative active material.
• the negative electrode plate mixture which forms the negative active material layer 16 contains arbitrary components such as a conductive agent, a binder, a thickening agent, a filler and the like when necessary.
• arbitrary components such as a conductive agent, a binder, a thickening agent, a filler and the like used for forming the negative active material layer 16
• arbitrary components substantially equal to the arbitrary components used for forming the positive active material layer 10 can be used.
• the negative active material a material which can occlude and discharge lithium ions is preferably used.
• metal such as lithium or a lithium alloy, for example, a metal oxide, a polyphosphoric acid compound, a carbon material such as graphite, non- crystalline carbon (easily graphitizable carbon or hardly graphitizable carbon), for example, or the like can be named.
• Si, an Si oxide, Sn, an Sn oxide or a combination of these materials it is preferable to use Si, an Si oxide, Sn, an Sn oxide or a combination of these materials. It is particularly preferable to use an Si oxide.
• Si and Sn can have a discharge capacity approximately three times as large as a discharge capacity of graphite when Si and Sn are used in the form of an oxide.
• a ratio of the number of atoms of oxygen (O) contained in an Si oxide with respect to the number of atoms of Si is preferably set to more than 0 to less than 2. That is, as Si oxide, a compound expressed as SiO x (0 ⁇ x ⁇ 2) is preferably used. Further, the ratio of the number of atoms of O with respect to the number of atoms of Si is preferably set to a value which falls within a range of from 0.5 to 1.5 inclusive.
• the above-mentioned materials may be used in a single form, or two or more kinds of the materials may be used by mixing.
• an Si oxide and other negative active materials by mixing, both discharge capacities per unit opposedly facing area between the positive electrode plate 7 and the negative electrode plate 6 and a ratio of a mass of the positive active material with respect to a mass of a negative active material described later can be adjusted to suitable values.
• carbon materials such as graphite, hard carbon, soft carbon, coke, acetylene black, Ketjen black, vapor phase growth carbon fibers, fullerene, and activated carbon can be named.
• carbon materials only one kind of material may be mixed with an Si oxide, or two or more kinds of materials may be mixed with an Si oxide in an arbitrary combination or at an arbitrary ratio.
• graphite having a relatively low charge- discharge potential is preferably used.
• graphite used in a form that graphite is mixed with an Si oxide flaky graphite, spherical graphite, artificial graphite, natural graphite and the like can be named.
• flaky graphite which can easily maintain its contact with Si oxide particle surfaces even when charging and discharging of the energy storage device are repeated is preferably used.
• a lower limit of a content of an Si oxide in the negative active material is preferably set to 30 mass%, more preferably set to 50 mass%, and further more preferably set to 70 mass%.
• an upper limit of the content of the Si oxide is usually set to 100 mass%, and preferably set to 90 mass%.
• the above-mentioned Si oxide (a material expressed by a general formula SiO x ) include both an S1O2 phase and an Si phase.
• Si oxide lithium is occluded in or discharged from Si in a matrix of S1O2 and hence, such an Si oxide exhibits a small change in volume and exhibits an excellent charge- discharge cycle characteristic.
• An average particle size of the Si oxide is preferably set to a value which falls within a range of from 1 ⁇ to 15 ⁇ inclusive.
• Si oxide various Si oxides can be used ranging from a high crystalline Si oxide to an amorphous Si oxide. Further, as the Si oxide, an Si oxide which is washed by an acid such as a hydrogen fluoride or a sulfuric acid, or an Si oxide which is reduced by hydrogen may be used.
• an acid such as a hydrogen fluoride or a sulfuric acid
• an Si oxide which is reduced by hydrogen may be used.
• the negative active material layer 16 may contain ⁇ a small amount of a typical nonmetallic element such as B, N, P, F, CI, Br, I; a typical metallic element such as Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge! and a transition metallic element such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, W in addition to an Si oxide.
• a typical nonmetallic element such as B, N, P, F, CI, Br, I
• a typical metallic element such as Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge!
• a transition metallic element such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, W in addition to an Si oxide.
• a lower limit of a content of the negative active material in the negative active material layer 16 is preferably set to 60 mass%, more preferably set to 80 mass%, and further more preferably set to 90 mass%.
• an upper limit of the content of the negative active material is preferably set to 99 mass%, and more preferably set to 98 mass%.
• a lower limit of a content of a binder in the negative active material layer 16 is preferably set to 1 mass%, and more preferably set to 5 mass%.
• an upper limit of the content of the binder is preferably set to 20 mass%, and more preferably set to 15 mass%.
• a lower limit of an average thickness of the negative active material layer 16 is preferably set to 10 ⁇ , and more preferably set to 20 ⁇ .
• an upper limit of the average thickness of the negative active material layer 16 is preferably set to 100 ⁇ , and more preferably set to 80 ⁇ .
• the outer case 2 is a hermetically-closed container which
• the outer case 2 As a material for forming the outer case 2, provided that the material has sealability capable of sealing electrolyte and a strength capable of protecting the layered electrode assembly 1, a resin or the like may be used, for example. However, metal is preferably used. In other words, although the outer case 2 may be a bag-shaped body formed of laminated film and having flexibility or the like, for example, it is preferable to use a robust metal case capable of protecting the layered electrode assembly 1 with more certainty.
• a known electrolyte solution usually used in the energy storage device can be used.
• a cyclic carbonate such as an ethylene carbonate (EC), a propylene carbonate (PC) or a butylene carbonate (BC)
• a chain carbonate such as a diethyl carbonate (DEC), a dimethyl carbonate (DMC) or an ethyl- methyl carbonate (EMC)
• a positive electrode plate and separators were prepared.
• the positive electrode plate was prepared by stacking a positive electrode active material layer on an aluminum-foil-made positive electrode current collector.
• the separator was prepared by stacking a heat resistant layer having a thickness of 4 ⁇ on a resin layer having a thickness of 16 ⁇ and formed of a plurality of large-thickness film layers made of polyethylene and polypropylene respectively, and by stacking an adhesive layer having a thickness of 1 ⁇ and containing non-aqueous electrolyte particles and a binder on the heat resistant layer.
• the positive electrode plate was sandwiched between the pair of separators in a state where the adhesive layers of the pair of separators are disposed inside.
• the adhesive layers of the separators were welded to each other outside an active material stacked region of the positive electrode plate and, at the same time, by making the adhesive layers of the separators adhere to the tab of the positive electrode plate, an example of the bag-packed positive electrode plate according to the present invention was obtained.
• Forty bag-packed positive electrode plates and forty negative electrode plates were stacked in such a manner that the bag- packed positive electrode plate and the negative electrode plate are stacked alternately, these electrode plates were accommodated in an aluminum- made box- shaped outer case, and an electrolyte solution was poured into the outer case thus forming an energy storage device according to an example of the present invention.
• a capacity was 40 Ah
• energy density on a weight basis was 107 Hh/kg
• energy density on a volume basis was 241 Wh/L.
• Energy storage devices according to comparison examples were prepared in the same manner except for that a heat resistant layer having a thickness of 4 ⁇ was stacked on a resin layer having a thickness of 16 ⁇ , and the energy storage devices of the comparison examples had no adhesive layers.
• a capacity, energy density on a weight basis and energy density on a volume basis of the energy storage devices of the comparison examples were set equal to those of the energy storage devices according to the examples of the present invention.
• a plurality of energy storage devices according to the examples and a plurality of energy storage devices according to the comparison examples were prepared. Tests were carried out in such a manner that a nail- shaped body made of SUS304 having a diameter of 1 mm and a distal end angle of 30° was driven at a speed of 80 mm/sec such that the nail-shaped body penetrated an active material stacked region of a negative electrode plate and a tab of a positive electrode plate, and a change in temperature at the center of the energy storage device and a change in temperature at an edge of the energy storage device in the vicinity of a position where the nail- shaped body was inserted was measured. The tests were performed by changing a driven depth of the nail-shaped body.
• the temperature of the energy storage device was not increased to a temperature which causes a burn on a hand of a user even when the user erroneously touches the edge part.
• the bag-packed positive electrode plate, the layered electrode assembly, and the energy storage device according to the present invention are preferably applicable to a secondary battery, and are particularly preferably used as a power source for a vehicle such as an electric vehicle or a plug-in hybrid electric vehicle (PHEV).
• a vehicle such as an electric vehicle or a plug-in hybrid electric vehicle (PHEV).
• PHEV plug-in hybrid electric vehicle

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