WO2013031012A1 - 非水電解質二次電池 - Google Patents
非水電解質二次電池 Download PDFInfo
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- WO2013031012A1 WO2013031012A1 PCT/JP2011/069962 JP2011069962W WO2013031012A1 WO 2013031012 A1 WO2013031012 A1 WO 2013031012A1 JP 2011069962 W JP2011069962 W JP 2011069962W WO 2013031012 A1 WO2013031012 A1 WO 2013031012A1
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- sheet
- separator sheet
- secondary battery
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- filler layer
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- 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
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
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- 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
- H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
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- 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
- H01M50/443—Particulate material
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- 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
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- 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
- H01M50/463—Separators, membranes or diaphragms characterised by their shape
- H01M50/466—U-shaped, bag-shaped or folded
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- 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
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
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- 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
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M50/491—Porosity
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- 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
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- 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 non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery in which a filler layer is provided on one side of a separator.
- lithium secondary batteries In recent years, lithium secondary batteries, nickel-metal hydride batteries and other secondary batteries have been used as on-vehicle power supplies or personal computers and portable terminals.
- a lithium secondary battery that is lightweight and has a high energy density is gaining importance as a high-output power supply for vehicles.
- One typical configuration of this type of lithium secondary battery includes an electrode body (winding electrode body) having a structure in which a sheet-like electrode is wound in a spiral shape.
- a wound electrode body includes, for example, a positive electrode sheet having a structure in which a positive electrode active material layer containing a positive electrode active material is held on both surfaces of a positive electrode current collector, and a negative electrode active material layer containing a negative electrode active material.
- the negative electrode sheet having a structure held on both sides of the sheet is wound around the separator sheet in a spiral shape.
- a porous resin sheet made of polyethylene (PE), polypropylene (PP) or the like has been used as a separator sheet. Since the separator sheet is porous, heat shrinkage occurs when the temperature increases. Using this, the shutdown function works. However, if the degree of thermal contraction is large, a local short circuit due to a membrane breakage or the like may occur, and the short circuit may further expand therefrom. Therefore, in order to prevent thermal contraction of the separator sheet, it has been proposed to form a filler layer (porous heat-resistant layer) on the surface of the separator sheet (Patent Document 1, etc.).
- a filler layer porous heat-resistant layer
- the separator sheet tends to expand and contract, and the filler layer tends not to expand and contract. Therefore, as shown in FIGS. 9 and 10, if a filler layer is provided only on one side of the separator sheet 90, the separator sheet 90 and the filler layer may have a difference in expansion and contraction when the environment such as heat and humidity changes.
- the end of the sheet 90 is rolled up, and a curl (warp deformation) 92 is generated on the innermost circumferential surface and the outermost circumferential surface of the wound electrode body 94.
- Such a curl 92 may reduce the insertion property when the electrode body 94 is inserted into the battery case or the winding core is inserted into the electrode body 94, and may cause a production failure.
- a step 96 may be formed on the surface and the innermost peripheral surface.
- a restraining load for example, a restraining load applied to suppress the swelling of the battery
- the present invention aims to solve the above problems.
- a non-aqueous electrolyte secondary battery is a non-aqueous electrolyte secondary battery including a wound electrode body (preferably flat shape) in which a positive electrode sheet and a negative electrode sheet are wound through a porous separator sheet. is there.
- a filler layer containing an inorganic filler and a binder is formed on one side of the separator sheet.
- the filler layer is provided continuously from the winding start end to the winding end of the separator sheet in the winding direction.
- the separator sheet has a low porosity region having a lower porosity than a portion other than the region in a region having a predetermined width from the winding start end and / or winding end of the sheet toward the center of the sheet.
- the low porosity region is formed in a region having a predetermined width from the winding start end and / or winding end of the separator sheet toward the center of the sheet. Even if the degree of expansion and contraction decreases and the environment such as heat and humidity changes, the difference in expansion and contraction between the separator sheet and the filler layer decreases. As a result, the stress that causes curling (warping deformation) starting from the end is relaxed, and curling of the separator sheet is suppressed.
- a separator sheet By using such a separator sheet, a high-performance nonaqueous electrolyte secondary battery in which various problems due to curling are eliminated can be constructed.
- the low porosity region is formed by compressing a region having a predetermined width from the end of the separator sheet. According to such a configuration, the low porosity region can be easily formed. Or you may form a low porosity area
- X [(H2 ⁇ H1) / H2] ⁇ 100
- the vacancy reduction rate X satisfies 5 ⁇ X ⁇ 90. If the pore reduction rate X is too small, the curl generation suppressing effect described above may not be sufficiently obtained. On the other hand, if the pore reduction rate X is too large, the curl generation suppression effect improvement rate is slowed down, so that there is not much merit, and in addition, the flexibility of the region near the end of the separator sheet is reduced. When winding a sheet and constructing a wound electrode body, inconvenience such as winding failure may occur.
- the width of the low porosity region is 2 mm to 40 mm.
- the width in which the low porosity region is provided is 2 mm or more (preferably 5 mm or more, particularly preferably 10 mm or more)
- the curl generation suppressing effect described above can be sufficiently exhibited.
- the width of the low porosity region is too wide, the waste portion of the separator sheet increases and the cost may increase. From the viewpoint of cost reduction, approximately 40 mm or less is appropriate, and for example, 30 mm or less is particularly preferable.
- the filler layer has a thickness of 5 ⁇ m or less.
- the thickness of the filler layer is 5 ⁇ m or less, it is advantageous in that the ion permeability of the filler layer is improved.
- the shape retention force by the filler layer is reduced, so that the separator sheet is easily curled. Therefore, when the thickness of the filler layer is 5 ⁇ m or less, the effect of the configuration of the present invention that suppresses the occurrence of curling by providing a low porosity region in a region having a predetermined width from the end of the separator sheet can be exhibited particularly well.
- the material of the inorganic filler is not particularly limited, but may be made of at least one inorganic compound selected from the group consisting of alumina, magnesia, zirconia, silica, boehmite, and titania. Since these inorganic compounds have a high melting point and excellent heat resistance, they are preferably used as inorganic fillers (typically in powder form) suitable for the purpose of the present invention.
- the separator sheet with a filler layer has the following characteristics: After the low porosity region of the separator sheet is cut and removed, when left on a horizontal plane for 1 hour, it is defined as the angle formed by the trajectory drawn by the tip of the cut end floating from the horizontal plane of the sheet and the horizontal plane. The curl angle is 90 ° or more; Have Since the separator sheet having such characteristics is likely to be curled, it is particularly meaningful to apply the present invention.
- any of the nonaqueous electrolyte secondary batteries disclosed herein has less battery curl and excellent battery performance (for example, cycle characteristics), so that the nonaqueous electrolyte secondary battery mounted on a vehicle such as an automobile is used. (For example, it is suitable as a lithium secondary battery). Therefore, according to the present invention, for example, a non-aqueous electrolyte secondary battery (which may be in the form of an assembled battery in which a plurality of non-aqueous electrolyte secondary batteries are connected) is used as a power source (typically a hybrid vehicle or an electric vehicle). A vehicle (for example, an automobile) mounted as a power source can be provided.
- FIG. 1 is a side view schematically showing a nonaqueous secondary battery according to an embodiment of the present invention.
- 2 is a cross-sectional view taken along line II-II in FIG.
- FIG. 3 is a schematic diagram for explaining a wound electrode body used in a nonaqueous secondary battery according to an embodiment of the present invention.
- FIG. 4 is a diagram schematically showing a wound electrode body used in the nonaqueous secondary battery according to an embodiment of the present invention.
- FIG. 5 is a cross-sectional view schematically showing a separator sheet used in a non-aqueous secondary battery according to an embodiment of the present invention.
- FIG. 6 is a top view of FIG.
- FIG. 7 is a diagram for explaining the curl amount.
- FIG. 8 is a side view showing a vehicle equipped with a battery.
- FIG. 9 is a diagram schematically showing a conventional separator sheet.
- FIG. 10 is a diagram schematically showing a conventional wound electrode body.
- FIG. 11 is a diagram schematically illustrating a conventional flat wound electrode body.
- a lithium secondary battery in a form in which a wound electrode body (wound electrode body) and a nonaqueous electrolyte are housed in a rectangular battery case will be described below as an example. The invention will be described in detail.
- This lithium secondary battery 100 includes a long positive electrode sheet 10 and a long negative electrode sheet 20 laminated and wound through a long separator sheet 30 (winding electrode).
- Body 80 is housed in a battery case 50 having a shape (box shape) capable of housing the wound electrode body 80 together with a non-aqueous electrolyte (not shown).
- the battery case 50 includes a box-shaped case main body 52 whose upper end is opened, and a lid 54 that closes the opening.
- a metal material such as aluminum, steel, or Ni plating SUS is preferably used.
- a positive electrode terminal 70 that is electrically connected to the positive electrode 10 of the wound electrode body 80 and a negative electrode terminal 72 that is electrically connected to the negative electrode 20 of the wound electrode body 80.
- a wound electrode body 80 is accommodated together with a non-aqueous electrolyte (not shown).
- the wound electrode body 80 is the same as the wound electrode body of a normal lithium secondary battery except for the configuration of the separator sheet 30 described later, and as shown in FIG. Before assembling 80, it has a long sheet structure (sheet-like electrode body).
- the positive electrode sheet 10 has a structure in which a positive electrode active material layer 14 containing a positive electrode active material is held on both surfaces of a long sheet-like foil-shaped positive electrode current collector 12. However, the positive electrode active material layer 14 is not attached to one side edge (the lower side edge portion in the figure) along the edge in the width direction of the positive electrode sheet 10, and the positive electrode current collector 12 has a constant width. An exposed positive electrode active material layer non-forming portion is formed.
- the negative electrode sheet 20 has a structure in which a negative electrode active material layer 24 containing a negative electrode active material is held on both surfaces of a long sheet-like foil-shaped negative electrode current collector 22.
- the negative electrode active material layer 24 is not attached to one side edge (the upper side edge portion in the figure) along the edge in the width direction of the negative electrode sheet 20, and the negative electrode current collector 22 is exposed with a certain width.
- a negative electrode active material layer non-formed portion is formed.
- the positive electrode sheet 10 and the negative electrode sheet 20 are laminated via two separator sheets 30 to produce a sheet-like electrode body.
- the positive electrode sheet 10 and the negative electrode sheet 20 are formed such that the positive electrode active material layer non-formation part of the positive electrode sheet 10 and the negative electrode active material layer non-formation part of the negative electrode sheet 20 protrude from both sides in the width direction of the separator sheet 30. Are overlapped slightly in the width direction.
- the wound electrode body 80 can be produced by winding the sheet-like electrode body produced by overlapping in this way.
- a wound core portion 82 (that is, the positive electrode active material layer 14 of the positive electrode sheet 10, the negative electrode active material layer 24 of the negative electrode sheet 20, and the separator sheet 30 is densely arranged in the central portion of the wound electrode body 80 in the winding axis direction. Laminated portions) are formed. Further, the electrode active material layer non-forming portions of the positive electrode sheet 10 and the negative electrode sheet 20 protrude outward from the wound core portion 82 at both ends of the wound electrode body 80 in the winding axis direction.
- a positive electrode lead terminal 74 and a negative electrode lead terminal 76 are provided on the positive electrode side protruding portion (that is, the non-formed portion of the positive electrode active material layer 14) 84 and the negative electrode side protruding portion (that is, the non-formed portion of the negative electrode active material layer 24) 86, respectively. Attached and electrically connected to the positive terminal 70 and the negative terminal 72 described above.
- the constituent elements of the wound electrode body 80 may be the same as those of the conventional wound electrode body of the lithium secondary battery except for the separator sheet 30, and are not particularly limited.
- the positive electrode sheet 10 may be formed by applying a positive electrode active material layer 14 mainly composed of a positive electrode active material for a lithium secondary battery on a long positive electrode current collector 12.
- a positive electrode active material layer 14 mainly composed of a positive electrode active material for a lithium secondary battery on a long positive electrode current collector 12.
- an aluminum foil or other metal foil suitable for the positive electrode is preferably used.
- the positive electrode active material one type or two or more types of materials conventionally used in lithium ion batteries can be used without any particular limitation.
- LiNiO 2 lithium nickel oxide
- LiCoO 2 lithium cobalt oxide
- LiMn 2 O 4 lithium manganese oxide
- the negative electrode sheet 20 may be formed by applying a negative electrode active material layer 24 mainly composed of a negative electrode active material for a lithium secondary battery on a long negative electrode current collector 22.
- a negative electrode active material layer 24 mainly composed of a negative electrode active material for a lithium secondary battery on a long negative electrode current collector 22.
- a copper foil or other metal foil suitable for the negative electrode is preferably used.
- the negative electrode active material one or more of materials conventionally used in lithium secondary batteries can be used without any particular limitation.
- Preferable examples include carbon-based materials such as graphite carbon and amorphous carbon, lithium-containing transition metal oxides and transition metal nitrides.
- a polyolefin-based resin such as polyethylene (PE) or polypropylene (PP) can be suitably used.
- the structure of the separator sheet 30 may be a single layer structure or a multilayer structure.
- the separator sheet 30 is made of PE resin.
- the PE resin a homopolymer of ethylene is preferably used.
- the PE resin is a resin containing 50% by mass or more of a repeating unit derived from ethylene, and is a copolymer obtained by polymerizing an ⁇ -olefin copolymerizable with ethylene, or at least copolymerizable with ethylene. It may be a copolymer obtained by polymerizing one kind of monomer.
- the ⁇ -olefin include propylene.
- other monomers include conjugated dienes (for example, butadiene) and acrylic acid.
- the separator sheet 30 is preferably made of PE having a shutdown temperature of about 120 ° C. to 140 ° C. (typically 125 ° C. to 135 ° C.).
- the shutdown temperature is sufficiently lower than the heat resistant temperature of the battery (for example, about 200 ° C. or higher).
- PE include polyolefins generally referred to as high-density polyethylene or linear (linear) low-density polyethylene.
- various types of branched polyethylene having medium density and low density may be used.
- additives such as various plasticizers and antioxidants, can also be contained as needed.
- a uniaxially stretched or biaxially stretched porous resin sheet can be suitably used.
- a porous resin sheet that is uniaxially stretched in the longitudinal direction (MD direction: MachineionDirection) is particularly preferable because it has moderate strength and little thermal shrinkage in the width direction.
- MD direction MachineionDirection
- the porous resin sheet uniaxially stretched in the longitudinal direction is particularly suitable as a material for the separator sheet constituting the wound electrode body.
- the thickness of the separator sheet 30 is preferably about 10 ⁇ m to 30 ⁇ m, and more preferably about 15 ⁇ m to 25 ⁇ m. If the thickness of the separator sheet 30 is too large, the ion permeability of the separator sheet 30 may be reduced. On the other hand, if the thickness of the separator sheet 30 is too small, film breakage may occur.
- the thickness of the separator sheet 30 can be obtained by image analysis of an image taken with a scanning electron microscope (SEM).
- the separator sheet 30 is comprised by the single layer structure of PE layer here, the separator sheet of a multilayer structure may be sufficient.
- the filler layer 40 can be laminated on one of the PP layers.
- the number of layers of the separator sheet having a multilayer structure is not limited to 3, and may be 2 or 4 or more.
- the filler layer 40 is formed on one side of the separator sheet 30 constituting the wound electrode body.
- the filler layer 40 is formed along the longitudinal direction (winding direction) of the separator sheet 30.
- the filler layer 40 is disposed at the interface between the positive electrode sheet 10 and the separator sheet 30.
- the filler layer 40 includes an inorganic filler (typically particulate) and a binder.
- the inorganic filler is fixed to the surface of the separator sheet 30 by the binder, and the inorganic fillers are bound to each other. A large number of voids are formed between the adjacent inorganic fillers at sites not bound by the binder.
- a non-aqueous electrolyte here, a non-aqueous electrolyte
- a non-aqueous electrolyte By impregnating the filler layer 40 with the non-aqueous electrolyte, movement of Li ions between the electrodes 10 and 20 is ensured. Sufficient battery output can be obtained.
- the inorganic filler constituting the filler layer is preferably a material having high electrical insulation and a melting point higher than that of the separator sheet 30.
- the material can be, for example, a metal oxide, hydroxide, nitride, or the like.
- the form of the inorganic material can be in the form of particles, fibers, flakes, and the like. Usually, it is preferable to use a particulate inorganic material. Particles made of inorganic oxide or inorganic hydroxide can be suitably used. For example, alumina, boehmite, magnesia, titania, silica, zirconia and the like are exemplified.
- Particularly preferred inorganic compounds include alumina, boehmite, magnesia and titania. These inorganic compounds may be used individually by 1 type, and may be used in combination of 2 or more type. According to these inorganic compounds, heat resistance and mechanical strength can be suitably ensured.
- the volume-based average particle diameter (D50) of the inorganic compound based on the laser diffraction / scattering method can be, for example, about 0.1 ⁇ m to 1 ⁇ m.
- the binder used in the filler layer is for binding an inorganic filler, and the material itself constituting the binder is not particularly limited, and various materials can be used widely.
- the filler layer-forming paint described later is an aqueous solvent (a solution using water or a mixed solvent containing water as a main component as a binder dispersion medium)
- a polymer that is dispersed or dissolved in the aqueous solvent is used. be able to.
- the polymer that is dispersed or dissolved in the aqueous solvent include acrylic resins.
- the acrylic resin a homopolymer obtained by polymerizing monomers such as acrylic acid, methacrylic acid, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methyl methacrylate, ethylhexyl acrylate and butyl acrylate.
- the acrylic resin may be a copolymer obtained by polymerizing two or more of the above monomers. Further, a mixture of two or more of the above homopolymers and copolymers may be used.
- polyolefin resins such as styrene butadiene rubber (SBR) and polyethylene (PE), polytetrafluoroethylene (PTFE), and the like can be used. These polymers can be used alone or in combination of two or more. Among these, it is preferable to use an acrylic resin.
- the form of the binder is not particularly limited, and a particulate (powdered) form may be used as it is, or a solution prepared in the form of a solution or an emulsion may be used. Two or more kinds of binders may be used in different forms.
- the filler layer 40 can contain materials other than the above-described inorganic filler and binder as necessary. Examples of such materials include various polymer materials that can function as a thickening agent for the filler layer-forming paint described later. In particular, when an aqueous solvent is used, it is preferable to contain a polymer that functions as the thickener. As the polymer that functions as the thickener, carboxymethyl cellulose (CMC) and methyl cellulose (MC) are preferably used.
- CMC carboxymethyl cellulose
- MC methyl cellulose
- the proportion of the inorganic filler in the entire filler layer is suitably about 50% by mass or more (for example, 50% by mass to 99% by mass), preferably 80% by mass or more (for example, 80% by mass or more). 99 mass%), particularly preferably about 90 mass% to 99 mass%.
- the binder ratio in the filler layer 40 is suitably about 40% by mass or less, preferably 10% by mass or less, particularly preferably 5% by mass or less (eg, about 0.5% by mass to 3% by mass). It is.
- the content of the thickener is preferably about 3% by mass or less, and about 2% by mass or less (for example, about 0.5 mass% to 1 mass%) is preferable.
- the thickness of the filler layer 40 is preferably about 0.5 ⁇ m to 10 ⁇ m, and more preferably about 0.5 ⁇ m to 5 ⁇ m. If the thickness of the filler layer 40 is too large, the ion permeability of the filler layer 40 may be reduced. On the other hand, if the thickness of the filler layer 40 is too small, the strength (shape retention) is lowered, and film breakage may occur. In addition, the thickness of the filler layer 40 can be calculated
- the porosity of the filler layer 40 is preferably about 40% to 70%, and more preferably about 50% to 60%, for example. If the porosity of the filler layer 40 is too large, the strength may be insufficient and film breakage may occur easily. On the other hand, if the porosity of the filler layer 40 is too small, the amount of the electrolyte solution that can be held in the filler layer 40 decreases, and the ion permeability may decrease.
- FIG. 5 is a schematic cross-sectional view showing an enlarged part of a cross section along the longitudinal direction (winding direction) of the long separator sheet 30 which is a stage before constructing the wound electrode body.
- the sheet 30 and the filler layer 40 provided on one side of the separator sheet 30 are shown.
- FIG. 6 is a top view of FIG. The left side in the figure is the winding start end side (winding center side), and the right side is the winding end side (winding outer periphery side).
- the filler layer 40 is formed over the winding direction (longitudinal direction) of the separator sheet 30.
- the filler layer 40 is continuously provided in the winding direction of the separator sheet 30 from the winding start end portion 38A to the winding end portion 38B.
- the separator sheet 30, a predetermined width W A toward the sheet center from the winding start end 38A and the winding end portion 38B, W in the region of B, a site other than the region (typically winding direction center of the separator sheet (Part)
- Low porosity regions 36A and 36B having a porosity lower than that of 35 are provided.
- the low porosity regions 36A and 36B are formed by, for example, thermally compressing (pressing) a region having a predetermined width from the winding start end portion 38A and the winding end portion 38B of the separator sheet.
- the outermost circumferential surface and the innermost circumferential surface of the wound electrode body 80 are curled.
- the electrode body is inserted into the battery case or the winding core is inserted into the electrode body, as in the case of the occurrence of the occurrence of deterioration, it is possible to prevent deterioration of the insertability.
- a restraining load surface pressure as when steps are formed on the outermost and innermost circumferential surfaces of the wound electrode body due to bending of the curled portion. Can be prevented.
- the electrolyte (electrolyte) distribution will become non-uniform according to the non-uniformity of the pressure applied inside the wound electrode body, and there will be areas where the load is high during charging and discharging. It may occur and cycle characteristics (life) may be reduced.
- the separator sheet 30 does not curl.
- the surface pressure applied to the wound electrode body flat surface
- the surface pressure applied to the wound electrode body can be made uniform without forming steps on the outer peripheral surface and the innermost peripheral surface. For this reason, problems due to non-uniformity of the restraining load (surface pressure) do not occur, the cycle characteristics and output characteristics are excellent, and a long life can be realized.
- the pore reduction rate X preferably satisfies 5 ⁇ X ⁇ 90, more preferably satisfies 10 ⁇ X ⁇ 90, and 15 Those satisfying ⁇ X ⁇ 65 are particularly preferable. If the pore reduction rate X is too small, the curl generation suppressing effect described above may not be sufficiently obtained.
- the pore reduction rate X is too large, the curl generation suppression effect improvement rate is slowed down, so that there is not much merit, and in addition, the flexibility of the region near the end of the separator sheet is reduced.
- inconvenience winding failure or the like
- the low porosity region in which the porosity reduction rate X is 10% or more and 65% or less is appropriate from the viewpoint of achieving both the curl generation suppressing effect and the production stability.
- the porosity H1 of the low porosity region is not particularly limited, but is preferably about 5% to 40%, and more preferably about 5% to 30%. By making it within the range of such a porosity H1, curling can be prevented appropriately. Further, the porosity H2 of the portion 35 excluding the low porosity region is preferably about 40% to 60%, more preferably about 45% to 55%, for example. If the porosity H2 of the portion 35 other than the low porosity region is too small, the amount of the electrolyte solution that can be held in the separator sheet 30 may be reduced, and the ion permeability may be reduced. On the other hand, the porosity H2 is large. If it is too high, the strength of the separator sheet 30 may be insufficient, and film breakage may occur.
- the porosity H1 of the low porosity region is in the range of 5% to 40%, and the porosity H2 of the portion other than the region is 40% to 60%.
- the porosity H1 of the low porosity region is in the range of 5% to 30%, and the porosity H2 of the portion other than the region is in the range of 45% to 55%. And the like.
- the porosity H2 [%] of the separator sheet 30 (excluding the low porosity region) can be calculated as follows.
- the apparent volume occupied by the separator sheet of unit area (size) is Va [cm 3 ], and the mass of the separator sheet is W [g].
- the ratio between the mass W and the true density ⁇ [g / cm 3 ] of the resin material constituting the separator sheet, that is, W / ⁇ is Vb.
- the porosity H2 of the separator sheet can be calculated by [(Va ⁇ Vb) / Va] ⁇ 100.
- the width W A, W B is the low porosity region is 5mm or 40mm or less (especially 10mm or 20mm or less), it is appropriate from the viewpoint of achieving both reduction curling suppression effect and cost.
- the width W A of the low porosity region of the wound starting end side, and the width W B of the low porosity region of the wound end side may be different may be the same.
- the widths W A and W B of the low porosity region can be appropriately selected according to battery usage conditions and the like.
- the low porosity regions 36A and 36B are provided on both the winding start end side and the winding end side is illustrated, but the present invention is not limited to this. It is also possible to provide a low porosity region only on one of the winding start end side and the winding end side. However, as in the above-described embodiment, it is preferable to provide the low porosity regions 36A and 36B on both the winding start end side and the winding end side in terms of more appropriately preventing problems due to the occurrence of curling.
- the separator sheet 30 with the filler layer 40 has the following characteristics: When the low porosity regions 36A and 36B of the separator sheet 30 are cut and removed and left on the horizontal surface 68 for 1 hour, a trajectory 64 drawn by the leading end 62 of the cut end floating from the horizontal surface 68 of the sheet 30 A curl angle ⁇ defined as an angle formed by the horizontal plane 68 is 90 ° or more (preferably 180 ° C. or more); A separator sheet having Since the separator sheet 30 having such characteristics is easily curled, it is particularly meaningful to apply this configuration.
- the filler layer forming coating material for forming the filler layer 40 a paste (including a slurry or ink, the same applies hereinafter) in which filler, binder and solvent are mixed and dispersed is used.
- the filler layer 40 can be formed by applying an appropriate amount of this paste-like paint on one side of the separator sheet 30 and further drying it.
- the solvent used for the filler layer-forming paint examples include water or a mixed solvent mainly composed of water.
- a solvent other than water constituting such a mixed solvent one or more organic solvents (lower alcohol, lower ketone, etc.) that can be uniformly mixed with water can be appropriately selected and used.
- it may be an organic solvent such as N-methylpyrrolidone (NMP), pyrrolidone, methyl ethyl ketone, methyl isobutyl ketone, ixahexanone, toluene, dimethylformamide, dimethylacetamide, or a combination of two or more thereof.
- NMP N-methylpyrrolidone
- pyrrolidone pyrrolidone
- methyl ethyl ketone methyl isobutyl ketone
- ixahexanone ixahexanone
- toluene dimethylformamide, dimethylacetamide, or a combination of two or more thereof.
- the filler layer-forming coating material can contain one or more materials that can be used as necessary in addition to the filler and the binder.
- An example of such a material is a polymer that functions as a thickener for the coating material for forming an inorganic filler layer.
- a polymer that functions as the thickener it is preferable to contain a polymer that functions as the thickener.
- carboxymethyl cellulose (CMC) or polyethylene oxide (PEO) is preferably used.
- the operation of mixing the filler and binder with the solvent can be performed using an appropriate kneader such as a disper mill, a clear mix, a fill mix, a ball mill, a homodisper, or an ultrasonic disperser.
- the filler layer 40 can be formed by applying a filler layer-forming coating material on one side of the separator sheet 30 and drying it.
- the operation of applying the filler layer-forming coating material on one side of the separator sheet 30 can be used without any particular limitation on conventional general application means.
- a suitable coating apparatus gravure coater, slit coater, die coater, comma coater, dip coat, etc.
- a predetermined amount of the filler layer forming coating material is applied to one surface of the separator sheet 30. It can be applied by coating to a uniform thickness over 30 full lengths (from one end to the other).
- the coating material is dried by a suitable drying means (typically at a temperature lower than the melting point of the separator sheet 30, for example, 110 ° C. or less, for example, 50 to 80 ° C.) to form a filler layer forming coating material.
- a suitable drying means typically at a temperature lower than the melting point of the separator sheet 30, for example, 110 ° C. or less, for example, 50 to 80 ° C.
- the filler layer 40 containing an inorganic filler and a binder can be formed.
- low porosity regions 36A and 36B are then formed in regions of a predetermined width from the end portions 38A and 38B of the separator sheet toward the center of the sheet.
- the method for forming the low porosity regions 36A and 36B in the separator sheet 30 is not particularly limited.
- a region having a predetermined width from the end portions 38A and 38B of the separator sheet may be formed by thermal compression (pressing).
- the heating temperature is preferably lower than the melting point of the separator sheet 30, and is usually 180 ° C. or less, preferably about 50 ° C. to 120 ° C. It is.
- the pressure condition may be about 0.1 MPa to 2 MPa.
- the processing time may be about 0.5 seconds to 3 seconds.
- the porosity may be reduced by filling the pores of the separator sheet with resin.
- the resin to be filled is not particularly limited.
- the resin for example, PE
- PVdF polyvinylidene fluoride
- the low porosity regions 36A and 36B can be formed by applying (soaking) the regions of the separator sheet to the regions having a predetermined width from the end portions 38A and 38B and drying. .
- the formation of the low porosity regions 36A and 36B may be performed after the filler layer 40 is formed as described above, or may be performed before the filler layer 40 is formed.
- the two separator sheets 30, and the separately prepared positive electrode sheet 10 and negative electrode sheet 20, as shown in FIG. Laminate are formed such that the positive electrode active material layer non-formation part of the positive electrode sheet 10 and the negative electrode active material layer non-formation part of the negative electrode sheet 20 protrude from both sides in the width direction of the separator sheet 30. Are overlapped slightly in the width direction.
- the separator sheet 30 sandwiched between the positive electrode sheet 10 and the negative electrode sheet 20 is disposed so that the filler layer 40 formed on one surface of the separator sheet 30 faces the positive electrode sheet 10.
- the separator sheet 30 superimposed on the lower surface of the negative electrode sheet 20 is disposed so that the filler layer 40 formed on one side of the separator sheet 30 faces the side opposite to the negative electrode sheet 20.
- the separator 30, the negative electrode sheet 20, the separator 30, and the positive electrode sheet 10 are overlapped and wound in the longitudinal direction of the sheet while applying tension to each sheet, whereby a wound body can be manufactured.
- the flat wound electrode body 80 can be constructed by crushing the wound body from the side surface direction.
- the wound electrode body 80 is accommodated in the main body 52 from the upper end opening of the case main body 52 and an electrolyte containing an appropriate supporting salt is disposed in the case main body 52.
- Supporting salt is a lithium salt such as LiPF 6, for example.
- an appropriate amount (for example, concentration 1M) of a lithium salt such as LiPF 6 is dissolved in a mixed solvent of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate (for example, a mass ratio of 3: 4: 3) to prepare an electrolyte (typically It can be used as a liquid electrolyte (that is, an electrolytic solution).
- the opening is sealed by welding or the like with the lid 54, and the assembly of the lithium secondary battery 100 according to the present embodiment is completed.
- the process of sealing the battery case 50 and the process of placing (injecting) the electrolyte may be the same as those used in the manufacture of conventional lithium secondary batteries, and do not characterize the present invention. In this way, the construction of the lithium secondary battery 100 according to this embodiment is completed.
- test examples relating to the present invention will be described, but the present invention is not intended to be limited to those shown in the following test examples.
- ⁇ -alumina powder (average particle size (D50) 0.7 ⁇ m) as an inorganic filler, PVdF as a binder, and NMP so that the mass ratio of these materials is 96: 4,
- a filler layer-forming coating material was prepared. This filler layer forming coating is applied to a predetermined area on one side of a separator sheet (a porous PE sheet having a thickness of 18 ⁇ m and a porosity of 50%) with a gravure roll, and dried, whereby one side of the separator sheet is applied. A separator sheet on which a filler layer was formed was obtained.
- a total of three types of samples with different average thicknesses of the filler layers were produced (separator sheets 1 to 3). The average thickness of the filler layer of each sample is as shown in Table 1.
- a wound electrode body was produced using the separator sheet 3 with a curl angle exceeding 180 °.
- the wound electrode body was produced as follows.
- a low porosity region is formed by thermally compressing a region having a predetermined width from both ends in the longitudinal direction of the separator sheet 3 toward the center of the sheet with a hot press machine (roll press machine) adjusted to 120 ° C. did.
- the width of the low porosity region was about 2 mm.
- ⁇ Preparation of positive electrode sheet> An aluminum foil (positive electrode current collector) is prepared, and a positive electrode active material layer (nickel cobalt lithium manganate (LiNi 1/3 Co 1/3 Mn 1/3 O as a positive electrode active material) is formed on a predetermined region of the surface by a conventional method. 2 ) A layer containing 85% by mass, 10% by mass of AB as a conductive material, and 5% by mass of PVdF as a binder was formed to prepare a positive electrode sheet.
- a positive electrode active material layer nickel cobalt lithium manganate (LiNi 1/3 Co 1/3 Mn 1/3 O as a positive electrode active material) is formed on a predetermined region of the surface by a conventional method. 2
- a copper foil (negative electrode current collector) was prepared, and a negative electrode active material layer (98% by mass of graphite as a negative electrode active material, 1% by mass of SBR as a binder, and a thickener as a predetermined region on the surface thereof by a conventional method.
- a layer containing 1% by mass of CMC was formed to prepare a negative electrode sheet.
- Example 2 A wound electrode body was produced in the same manner as in Example 1 except that the width of the low porosity region of the separator sheet was 5 mm.
- Example 3 A wound electrode body was produced in the same manner as in Example 1 except that the width of the low porosity region of the separator sheet was 10 mm.
- Example 4 A wound electrode body was produced in the same manner as in Example 1 except that the width of the low porosity region of the separator sheet was 20 mm.
- Example 1 A wound electrode body was produced in the same manner as in Example 1 except that the low porosity region was not provided in the separator sheet.
- Example 2 A wound electrode body was produced in the same manner as in Example 1 except that the separator sheet 2 was used and the separator sheet was not provided with a low porosity region.
- Example 3 the width of the low porosity region was fixed at 10 mm, and as shown in Table 3, a total of four types of flat wound electrode bodies with different porosity reduction rates X were produced. (Examples 5 to 8).
- a wound electrode body was produced in the same manner as in Example 3 except that the pore reduction rate X was changed as shown in Table 3. And the presence or absence of the separator sheet bending (curl bending, step) was visually confirmed. The results are shown in Table 3.
- the rate of breakage tended to decrease as the vacancy reduction rate increased.
- the rate of breakage could be reduced to 10% or less by setting the vacancy reduction rate to 15% or more.
- the porosity reduction rate is appropriately 5% or more (for example, 5% or more and 90% or less), preferably 10% or more (for example, 10% or more and 90% or less), and more preferably 15%. Or more (for example, 15% or more and 90% or less), and particularly preferably 40% or more (for example, 40% or more and 90% or less).
- the type of battery is not limited to the lithium secondary battery described above, but may be a battery having various contents with different electrode body constituent materials and electrolytes, for example, a nickel hydrogen battery, a nickel cadmium battery, or an electric double layer capacitor. .
- the shape (outer shape and size) of the nonaqueous electrolyte secondary battery to be constructed is not particularly limited.
- the outer package may be a thin sheet type constituted by a laminate film or the like, and the battery outer case may be a cylindrical or cuboid battery, or may be a small button shape.
- the filler layer is formed on the surface of the separator sheet on the positive electrode sheet side, but the present invention is not limited to this.
- the filler layer may be disposed on the negative electrode sheet side.
- any of the nonaqueous electrolyte secondary batteries 100 disclosed herein can be provided with performance suitable as a battery mounted on a vehicle (for example, good cycle characteristics can be obtained). Therefore, according to the present invention, as shown in FIG. 8, there is provided a vehicle 1 including any of the nonaqueous electrolyte secondary batteries 100 disclosed herein.
- a vehicle 1 for example, an automobile
- the nonaqueous electrolyte secondary battery 100 is provided as a power source (typically, a power source of a hybrid vehicle or an electric vehicle) is provided.
Abstract
Description
該セパレータシートの低空孔率領域を切断して除去した後、水平面に1時間放置した場合において、該シートの水平面から浮き上がった切断端部の先端が描く軌跡と水平面とがなす角度として規定されるカール角が、90°以上である;
を有する。かかる特性を有するセパレータシートはカールが生じやすいことから、本発明を適用することが特に有意義である。
本発明の一実施形態に係るリチウム二次電池の概略構成を図1~4に示す。このリチウム二次電池100は、長尺状の正極シート10と長尺状の負極シート20とが長尺状のセパレータシート30を介して積層されて捲回された形態の電極体(捲回電極体)80が、図示しない非水電解質とともに、該捲回電極体80を収容し得る形状(箱型)の電池ケース50に収容された構成を有する。
本実施形態に係る捲回電極体80は、後述するセパレータシート30の構成を除いては通常のリチウム二次電池の捲回電極体と同様であり、図3に示すように、捲回電極体80を組み立てる前段階において長尺状のシート構造(シート状電極体)を有している。
かかる捲回電極体80を構成する構成要素は、セパレータシート30を除いては、従来のリチウム二次電池の捲回電極体と同様でよく、特に制限はない。例えば、正極シート10は、長尺状の正極集電体12の上にリチウム二次電池用正極活物質を主成分とする正極活物質層14が付与されて形成され得る。正極集電体12にはアルミニウム箔その他の正極に適する金属箔が好適に使用される。正極活物質としては、従来からリチウムイオン電池に用いられる物質の一種または二種以上を特に限定することなく使用することができる。ここに開示される技術の好ましい適用対象として、リチウムニッケル酸化物(例えばLiNiO2)、リチウムコバルト酸化物(例えばLiCoO2)、リチウムマンガン酸化物(例えばLiMn2O4)等の、リチウムと遷移金属元素とを構成金属元素として含む酸化物(リチウム遷移金属酸化物)を主成分とする正極活物質が挙げられる。
負極シート20は、長尺状の負極集電体22の上にリチウム二次電池用負極活物質を主成分とする負極活物質層24が付与されて形成され得る。負極集電体22には銅箔その他の負極に適する金属箔が好適に使用される。負極活物質は従来からリチウム二次電池に用いられる物質の一種または二種以上を特に限定することなく使用することができる。好適例として、グラファイトカーボン、アモルファスカーボン等の炭素系材料、リチウム含有遷移金属酸化物や遷移金属窒化物等が挙げられる。
正負極シート10、20間に使用されるセパレータシート30の材料としては、例えば、ポリエチレン(PE)やポリプロピレン(PP)等のポリオレフィン系の樹脂を好適に用いることができる。セパレータシート30の構造は、単層構造であってもよく、多層構造であってもよい。ここでは、セパレータシート30はPE系樹脂によって構成されている。PE系樹脂としては、エチレンの単独重合体が好ましく用いられる。また、PE系樹脂は、エチレンから誘導される繰り返し単位を50質量%以上含有する樹脂であって、エチレンと共重合可能なα‐オレフィンを重合した共重合体、あるいはエチレンと共重合可能な少なくとも一種のモノマーを重合した共重合体であってもよい。α‐オレフィンとして、プロピレン等が例示される。他のモノマーとして共役ジエン(例えばブタジエン)、アクリル酸等が例示される。
他方、上記の通り、本実施形態に係るリチウム二次電池100では、熱や湿度等の環境が変化してもセパレータシート30にカールが発生しないので、カール部分の折れ曲がりにより捲回電極体の最外周面及び最内周面に段差が形成されることなく、捲回電極体(扁平面)にかかる面圧を均一化することができる。そのため、拘束荷重(面圧)の不均一さによる不具合が生じず、サイクル特性、出力特性に優れ、長寿命を実現することができる。
該セパレータシート30の低空孔率領域36A,36Bを切断して除去した後、水平面68に1時間放置した場合において、該シート30の水平面68から浮き上がった切断端部の先端62が描く軌跡64と水平面68とがなす角度として規定されるカール角θが、90°以上(好ましくは180℃以上)である;
を有するセパレータシートが挙げられる。かかる特性を有するセパレータシート30は、カールが生じやすいことから、本構成を適用することが特に有意義である。
本例では、無機フィラーとしてのα‐アルミナ粉末(平均粒径(D50)0.7μm)と、バインダとしてのPVdFと、それらの材料の質量比が96:4となるようにNMPと混合し、フィラー層形成用塗料を調製した。このフィラー層形成用塗料を、セパレータシート(厚み18μm、空孔率50%の多孔質PEシートを使用した。)の片面の所定領域にグラビアロールにより塗布、乾燥することにより、セパレータシートの片面にフィラー層が形成されたセパレータシートを得た。本例では、フィラー層の平均厚みが異なるサンプルを計3種類作製した(セパレータシート1~3)。各サンプルのフィラー層の平均厚みは表1に示すとおりである。
上記得られたセパレータシート1~3から、幅6cm、長さ10cmの試験片を採取し、水平面に載置した。そして、1時間経過後の試験片のカール角(°)を測定した。ここでカール角は、図7に示すように、該試験片60を水平面68に1時間放置した場合において、該試験片60の水平面68から浮き上がった切断端部の先端62が描く軌跡64と水平面68とがなす角度θとして規定するものとする。結果を表1に示す。
上記セパレータシート3の長手方向の両方の端部からシート中央に向けた所定幅の領域を、120℃に調整した熱プレス機(ロールプレス機)で熱圧縮することにより、低空孔率領域を形成した。低空孔率領域の幅は、約2mmとした。かかる低空孔率領域における空孔減少率Xを前述した式X=[(H2-H1)/H2]×100により算出したところ、約40%であった。
アルミニウム箔(正極集電体)を用意し、その表面の所定領域に常法によって正極活物質層(正極活物質としてのニッケルコバルトマンガン酸リチウム(LiNi1/3Co1/3Mn1/3O2)85質量%と、導電材としてのAB10質量%と、バインダとしてのPVdF5質量%とを含む層)を形成し、正極シートを作製した。
銅箔(負極集電体)を用意し、その表面の所定領域に常法によって負極活物質層(負極活物質としての黒鉛98質量%と、バインダとしてのSBR1質量%と、増粘剤としてのCMC1質量%とを含む層)を形成し、負極シートを作製した。
そして、正極シート及び負極シートを2枚のセパレータシートを介して積層し、捲回した。その際、正極シートと負極シートとの間に挟まれたセパレータシートは、該セパレータシートの片面に形成されたフィラー層が正極シートと対向するように配置した。一方、負極シートの下面に重ね合わされたセパレータシートは、該セパレータシートの片面に形成されたフィラー層が負極シートとは反対側を向くように配置した。次いで、積層体を捲回し、その捲回体を側面方向から押しつぶすことによって扁平形状の捲回電極体を作製した。
セパレータシートの低空孔率領域の幅を5mmにしたこと以外は実施例1と同様にして捲回電極体を作製した。
セパレータシートの低空孔率領域の幅を10mmにしたこと以外は実施例1と同様にして捲回電極体を作製した。
セパレータシートの低空孔率領域の幅を20mmにしたこと以外は実施例1と同様にして捲回電極体を作製した。
セパレータシートに低空孔率領域を設けなかったこと以外は、実施例1と同様にして捲回電極体を作製した。
セパレータシート2を使用し、かつセパレータシートに低空孔率領域を設けなかったこと以外は、実施例1と同様にして捲回電極体を作製した。
各例に係る扁平形状捲回電極体をそれぞれ10個ずつ作製し、セパレータシートの折れ(カールの折れ曲がり、段差)の有無を目視で確認した。その結果を表2に示す。
Claims (8)
- 正極シートと負極シートとが多孔質セパレータシートを介して捲回された捲回電極体を備えた非水電解質二次電池であって、
前記セパレータシートの片面には、無機フィラーとバインダとを含むフィラー層が形成されており、
前記フィラー層は、前記セパレータシートの捲回方向において該シートの捲回始端部から捲回終端部まで連続して設けられており、
前記セパレータシートは、該シートの捲回始端部及び/又は捲回終端部からシート中央に向けた所定幅の領域に、該領域以外の部位よりも空孔率が小さい低空孔率領域を有する、非水電解質二次電池。 - 前記低空孔率領域は、前記セパレータシートの端部から所定幅の領域を圧縮することにより形成されている、請求項1に記載の非水電解質二次電池。
- 前記セパレータシートの低空孔率領域の空孔率をH1とし、該領域以外の部位の空孔率をH2とした場合に、下記式(1)で表される空孔減少率Xが、5≦X≦90である、請求項1または2に記載の非水電解質二次電池。
X=[(H2-H1)/H2]×100 (1) - 前記低空孔率領域の幅が2mm~40mmである、請求項1~3の何れか一つに記載の非水電解質二次電池。
- 前記フィラー層の厚みが5μm以下である、請求項1~4の何れか一つに記載の非水電解質二次電池。
- 前記無機フィラーは、アルミナ、マグネシア、ジルコニア、シリカ、ベーマイト、及びチタニアからなる群から選択される少なくとも一種の無機化合物からなっている、請求項1~5の何れか一つに記載の非水電解質二次電池。
- 前記捲回電極体は、扁平形状の捲回電極体である、請求項1~6の何れか一つに記載の非水電解質二次電池。
- 前記フィラー層付きセパレータシートが以下の特性:
該セパレータシートの低空孔率領域を切断して除去した後、水平面に1時間放置した場合において、該シートの水平面から浮き上がった切断端部の先端が描く軌跡と水平面とがなす角度として規定されるカール角が、90°以上である;
を有する、請求項1~7の何れか一つに記載の非水電解質二次電池。
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JP2013530984A JP5828342B2 (ja) | 2011-09-01 | 2011-09-01 | 非水電解質二次電池 |
US14/342,078 US9219292B2 (en) | 2011-09-01 | 2011-09-01 | Nonaqueous electrolyte secondary battery |
DE112011105588.9T DE112011105588B4 (de) | 2011-09-01 | 2011-09-01 | Sekundärbatterie mit nichtwässrigem Elektrolyten |
CN201180073207.6A CN103765630B (zh) | 2011-09-01 | 2011-09-01 | 非水电解质二次电池 |
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JP (1) | JP5828342B2 (ja) |
CN (1) | CN103765630B (ja) |
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JP2015024658A (ja) * | 2013-06-21 | 2015-02-05 | 住友化学株式会社 | 積層多孔質フィルム、非水電解液二次電池用セパレータ及び非水電解液二次電池 |
JP5943148B1 (ja) * | 2015-04-20 | 2016-06-29 | 住友化学株式会社 | 積層多孔質フィルム、非水電解液二次電池用セパレータおよび非水電解液二次電池 |
WO2016121630A1 (ja) * | 2015-01-30 | 2016-08-04 | Jnc株式会社 | 多層耐熱セパレータ材およびその製造方法 |
JP2016201327A (ja) * | 2015-04-14 | 2016-12-01 | トヨタ自動車株式会社 | 非水電解質二次電池用セパレータおよびその製造方法 |
JP2017084539A (ja) * | 2015-10-26 | 2017-05-18 | 株式会社Gsユアサ | 蓄電素子及び蓄電素子の製造方法 |
JP2017130269A (ja) * | 2016-01-18 | 2017-07-27 | 株式会社Gsユアサ | 蓄電素子 |
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US10677587B2 (en) * | 2016-01-29 | 2020-06-09 | Sumitomo Chemical Company, Limited | Method for measuring curl in separator, slit device, and curl measurement device |
CN113471630B (zh) * | 2021-06-30 | 2023-10-10 | 宁德新能源科技有限公司 | 卷绕式电芯及电池 |
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Also Published As
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US9219292B2 (en) | 2015-12-22 |
CN103765630A (zh) | 2014-04-30 |
JP5828342B2 (ja) | 2015-12-02 |
CN103765630B (zh) | 2016-03-16 |
DE112011105588T5 (de) | 2014-07-03 |
US20140220402A1 (en) | 2014-08-07 |
JPWO2013031012A1 (ja) | 2015-03-23 |
DE112011105588B4 (de) | 2021-01-07 |
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