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WO2016071967A1 - Pile au lithium-ion et son procédé de fabrication - Google Patents

Pile au lithium-ion et son procédé de fabrication Download PDF

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Publication number
WO2016071967A1
WO2016071967A1 PCT/JP2014/079298 JP2014079298W WO2016071967A1 WO 2016071967 A1 WO2016071967 A1 WO 2016071967A1 JP 2014079298 W JP2014079298 W JP 2014079298W WO 2016071967 A1 WO2016071967 A1 WO 2016071967A1
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WO
WIPO (PCT)
Prior art keywords
separator
lithium ion
ion battery
positive electrode
negative electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2014/079298
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English (en)
Japanese (ja)
Inventor
祐介 加賀
利光 野口
和明 直江
新平 尼崎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to PCT/JP2014/079298 priority Critical patent/WO2016071967A1/fr
Publication of WO2016071967A1 publication Critical patent/WO2016071967A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • 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
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • 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 lithium ion battery and a method for producing the same, and more particularly to a lithium ion battery in which a positive electrode and a negative electrode are separated by a separator.
  • lithium ion secondary batteries have been attracting attention because they have the advantages of high energy density, long cycle life, low self-discharge characteristics, and high operating voltage. Lithium ion secondary batteries have the advantages described above, and are therefore widely used in portable electronic devices such as digital cameras, notebook personal computers, and mobile phones.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2007-280724 has a laminate formed by sequentially laminating a positive electrode, a separator, and a negative electrode, and at least one of the positive electrode and the negative electrode has a grain structure in consideration of high output.
  • a lithium ion battery is described as an electrochemical device including active material particles having a small diameter. In a lithium ion battery, discharging or charging is performed by moving lithium ions between a positive electrode and a negative electrode through pores opened in a separator.
  • Patent Document 1 provides pores that penetrate the laminate in the stacking direction of the laminate. Moreover, in patent document 1, in order to prevent that a short circuit arises when an active material falls from a positive electrode or a negative electrode, the average diameter of the said pore is made smaller than the average particle diameter of active material particle.
  • the average diameter of the pores opened in the separator is limited to be smaller than the average particle diameter of the active material particles, in order to reduce the internal resistance of the lithium ion battery and improve the output performance of the lithium ion battery It is difficult to improve the diffusibility of lithium ions in the separator.
  • a lithium ion battery has a positive electrode and a negative electrode containing an electrode active material, and a separator that separates the electrodes, and is a groove that penetrates from the front surface to the back surface of the separator, and has a short direction.
  • the slit width is less than the average diameter of the electrode active material and the length in the longitudinal direction is not less than the average diameter of the electrode active material.
  • the width in the short direction is less than the average diameter of the electrode active material, and the length in the longitudinal direction is greater than or equal to the average diameter of the electrode active material.
  • FIG. 8 is an overhead view showing a method for manufacturing the lithium ion battery following FIG. 7.
  • FIG. 9 is an overhead view showing a method for manufacturing a lithium ion battery following FIG. 8.
  • FIG. 10 is an overhead view showing a method for manufacturing the lithium ion battery following FIG. 9. It is an overhead view which shows the manufacturing method of the lithium ion battery following FIG.
  • FIG. 1 is a plan view of a positive electrode plate constituting the lithium ion battery of the present embodiment.
  • FIG. 2 is a plan view of the positive electrode plate constituting the lithium ion battery of the present embodiment.
  • FIG. 2 is a plan view of the negative electrode plate constituting the lithium ion battery of the present embodiment.
  • FIG. 3 is a schematic view showing a laminated structure of a laminated body constituting the lithium ion battery of the present embodiment.
  • FIG. 4 is an overhead view showing a wound body constituting the lithium ion battery according to the present embodiment.
  • FIG. 5 is a bird's-eye view showing a part of the lithium ion battery of the present embodiment.
  • FIG. 6 is a schematic diagram for explaining the operation of the lithium ion battery.
  • FIG. 1 shows a positive electrode sheet PEL constituting the positive electrode of the lithium ion battery of the present embodiment.
  • the positive electrode sheet PEL has a foil-like positive electrode plate PEP. Further, the positive electrode sheet PEL has an electrode material film PEF that is in contact with the positive electrode plate PEP so as to cover the surface of the positive electrode plate PEP and the back surface opposite to the front surface. That is, the positive electrode plate PEP is sandwiched between the pair of electrode material films PEF. In the figure, the electrode material film PEF on the back surface side of the positive electrode plate PEP is not shown.
  • the electrode material film PEF is formed by, for example, applying a slurry obtained by mixing a positive electrode active material PAS made of lithium cobalt oxide with carbon as a conductive additive and a binder to a positive electrode plate PEP, and then drying and solidifying the slurry. Film.
  • the binder (binder) between the positive electrode plate PEP and the positive electrode active material PAS is made of, for example, polyvinylidene fluoride.
  • the slurry of the positive electrode is formed by a solution in which the binder, the positive electrode active material PAS, and carbon as a conductive additive are dissolved in N methylpyrrolidone (NMP).
  • the average particle diameter of the plurality of particles (active material particles) constituting the positive electrode active material PAS is, for example, 10 ⁇ m.
  • the film thickness of the electrode material film PEF in contact with one surface of the positive electrode plate PEP is, for example, 10 to 100 ⁇ m. That is, the particles constituting the plurality of positive electrode active materials PAS are stacked on the surface of the positive electrode plate PEP.
  • the positive electrode sheet PEL made of the positive electrode plate PEP and the electrode material film PEF is a thin sheet extending in one direction. That is, the positive electrode plate PEP and the electrode material film PEF extend in the above-described direction, that is, the longitudinal direction.
  • the longitudinal direction of a sheet such as the positive electrode sheet PEL may be simply referred to as an X direction (first direction).
  • the surface of the electrode material film PEF, that is, the surface opposite to the surface in contact with the positive electrode plate PEP is smoothed.
  • a plurality of current collecting tabs PTAB are formed.
  • the short direction of a sheet such as the positive electrode sheet PEL may be simply referred to as a Y direction (second direction).
  • the plurality of positive electrode current collecting tabs PTAB are arranged along one side of the end of the positive electrode plate PEP in the Y direction, and are formed in an uncoated portion of the positive electrode active material PAS. That is, the positive electrode current collection tab PTAB is exposed from the positive electrode active material PAS, and a plurality of the positive electrode current collection tabs PTAB are arranged in the X direction along one side of the positive electrode sheet PEL.
  • FIG. 2 shows a negative electrode sheet NEL constituting the negative electrode of the lithium ion battery of the present embodiment.
  • the negative electrode sheet NEL has a foil-like negative electrode plate NEP.
  • the negative electrode sheet NEL has an electrode material film NEF that is in contact with the negative electrode plate NEP so as to cover the surface of the negative electrode plate NEP and the back surface opposite to the surface. That is, the negative electrode plate NEP is sandwiched between the pair of electrode material films NEF. In the figure, the electrode material film NEF on the back side of the negative electrode plate NEP is not shown.
  • the electrode material film NEF is formed by applying a slurry obtained by mixing carbon as a conductive additive and a binder (binder) to a negative electrode active material NAS made of a carbon material (carbon material) and then drying the slurry on the negative electrode plate NEP.
  • a binder binder
  • the binder (binder) between the negative electrode plate NEP and the negative electrode active material NAS is made of, for example, polyvinylidene fluoride.
  • the slurry of the negative electrode is formed by a solution in which the binder, the negative electrode active material NAS, and carbon as a conductive additive are dissolved in N methylpyrrolidone (NMP).
  • the average particle diameter of the plurality of particles (active material particles) constituting the negative electrode active material NAS is, for example, 10 ⁇ m.
  • the film thickness of the electrode material film NEF in contact with one surface of the negative electrode plate NEP is, for example, 10 to 100 ⁇ m. That is, the particles constituting the plurality of negative electrode active materials NAS are stacked on the surface of the negative electrode plate NEP.
  • the negative electrode sheet NEL made of the negative electrode plate NEP and the electrode material film NEF is a thin sheet extending in one direction. That is, the negative electrode plate NEP and the electrode material film NEF extend in the above-described direction, that is, the longitudinal direction (X direction).
  • the surface of the electrode material film NEF, that is, the surface opposite to the surface in contact with the negative electrode plate NEP is smoothed.
  • One end of the short direction (Y direction) that is along the surface of the negative electrode plate NEP and perpendicular to the longitudinal direction of the negative electrode plate NEP is cut and protruded in the Y direction.
  • a plurality of tabs NTAB are formed.
  • the plurality of negative electrode current collecting tabs NTAB are arranged along one side of the end of the negative electrode plate NEP in the Y direction, and are formed in an uncoated portion of the negative electrode active material NAS. That is, the negative electrode current collecting tab NTAB is exposed from the negative electrode active material NAS.
  • the electrode winding body WRF (see FIG. 4) is a laminate in which a positive electrode sheet PEL, a separator SP1, a negative electrode sheet NEL, and a separator SP2 are sequentially stacked, as shown in FIG. It is formed by winding.
  • the length of the laminate in the X direction is, for example, several tens of centimeters to several meters.
  • the slit part ST of the separator SP1 is opened between the positive electrode sheet PEL and the negative electrode sheet NEL.
  • the X direction and the Y direction are directions along the surface of the separator SP1 or SP2 facing the positive electrode sheet PEL or the negative electrode sheet NEL.
  • the separator SP1 and the separator SP2 shown in FIG. 3 are sheets made of an insulating material for insulating the positive electrode sheet PEL and the negative electrode sheet NEL.
  • each of the separators SP1 and SP2 is a sheet formed by stretching a resin film.
  • the positive electrode current collecting tab PTAB formed on one side in the short direction of the positive electrode sheet PEL and the negative electrode current collecting tab NTAB formed on one side in the short direction of the negative electrode sheet NEL are arranged on the opposite sides in the Y direction. Has been.
  • the separator SP1 is enlarged and shown in the lower part of the figure.
  • the separator SP2 has the same structure as the separator SP1.
  • Each of the plurality of slit portions ST reaches from the surface of the separator SP1 to the back surface opposite to the surface. That is, the slit part ST penetrates the separator SP1 in the thickness direction of the separator SP1.
  • Each slit part ST is a groove extending in the longitudinal direction of the separator SP1.
  • the shape of the opening of the slit part ST in plan view is a rectangle. However, the shape of the opening of the slit part ST in plan view may be a polygon such as a trapezoid or a hexagon, or an ellipse.
  • the extending direction of the slit part ST that is, the length L1 of each slit part ST in the X direction has a size equal to or larger than the respective average particle diameters of the positive electrode active material PAS and the negative electrode active material NAS, and in the X direction. It has a size smaller than the length of the separator SP1.
  • the width W1 of each slit portion ST in the Y direction is less than the average particle diameter of the positive electrode active material PAS and the negative electrode active material NAS.
  • the width W1 is 9 ⁇ m.
  • a width W2 between adjacent slit portions ST in the Y direction is, for example, about 1 cm.
  • each of the separators SP1 and SP2 is a sheet formed by stretching a resin film
  • the resin film has a three-dimensional network structure.
  • the resin film has a width larger than the width W1.
  • a large number of small pores (not shown) are opened.
  • the pore diameter is several tens to several hundreds nm. That is, the average diameter of the pores is less than the average particle diameter of each of the positive electrode active material PAS and the negative electrode active material NAS.
  • the material of the resin film for example, polyolefin resin, polyester, polyimide, polyamide, cellulose, or the like can be used.
  • the electrode winding body WRF is obtained by winding a laminated sheet (laminated body) in which a positive electrode sheet PEL, a separator SP1, a negative electrode sheet NEL, and a separator SP2 are superposed on an axis CR. Is formed.
  • the electrode winding body WRF is viewed from above in the extending direction of the axis CR, the positive electrode sheet PEL, the separator SP1, the negative electrode sheet NEL, and the separator SP2 are wound in a spiral shape around the axis CR. That is, the slit portion ST formed in the electrode winding body WRF extends in a spiral shape on the surface along the direction orthogonal to the extending direction of the shaft core CR.
  • FIG. 5 shows an overhead view of the lithium ion battery LB of the present embodiment.
  • the electrode winding body WRF and the like in the outer can CS are shown through the outer can CS and the cap CP, which are containers constituting the lithium ion battery LB.
  • the lithium ion battery LB has an outer can CS and a cap CP that seals the upper portion of the outer can CS.
  • An electrode winding body WRF is inserted into the outer can CS.
  • the electrolyte EL is injected (filled) into the outer can CS so that the entire electrode winding body WRF is immersed therein.
  • a positive electrode current collection ring PR is provided at one end in a direction (Y direction) along the central axis of the cylindrical electrode winding body WRF. That is, the positive electrode current collection ring PR is disposed at one end in the extending direction of the shaft core CR (see FIG. 4).
  • a plurality of positive current collecting tabs PTAB protruding from the positive electrode sheet PEL (see FIG. 4) constituting the electrode winding body WRF are connected to the positive current collecting ring PR. That is, the positive electrode current collection ring PR is electrically connected to the positive electrode sheet PEL (see FIG. 4) via the positive electrode current collection tab PTAB, and is not connected to the negative electrode sheet NEL.
  • the negative electrode current collector ring NR disposed at the other end in the Y direction of the electrode winding body WRF is electrically connected to the negative electrode sheet NEL (see FIG. 4) via a plurality of negative electrode current collector tabs NTAB. It is connected to the.
  • the side wall of the cylindrical outer can CS is partially recessed to form a groove DT.
  • the groove DT is formed along the side wall of the outer can CS so as to make one round around the central axis of the cylindrical outer can CS.
  • the groove DT is provided to fix the electrode winding body WRF inserted in the outer can CS so as not to move in the vertical direction.
  • the lithium ion battery LB of the present embodiment has a structure as described above.
  • the lithium ion battery is a kind of non-aqueous electrolyte secondary battery, and is a secondary battery in which lithium ions in the electrolyte are responsible for electrical conduction.
  • a lithium metal oxide is used for the positive electrode active material PAS, which is the amount of the positive electrode material
  • a carbon material such as graphite is used for the negative electrode active material NAS, which is the negative electrode material.
  • an organic solvent such as ethylene carbonate and a lithium salt such as lithium hexafluorophosphate (LiPF 6 ) are used for the electrolyte EL made of an electrolyte.
  • the electrolyte EL is a liquid filled in order to cause a charge / discharge reaction between the positive electrode PE and the negative electrode NE when a voltage is applied to the positive electrode PE or the negative electrode NE.
  • lithium ions exit from the positive electrode PE and enter the negative electrode NE during charging, and conversely during discharge, the lithium ions exit from the negative electrode NE and enter the positive electrode PE.
  • An Al foil made of Al (aluminum) is used for the positive electrode plate PEP that is the current collector foil of the positive electrode PE, and a Cu foil made of Cu (copper) is used for the negative electrode plate NEP that is the current collector foil of the negative electrode NE. It has been.
  • the lithium ion battery passes through the slit portion ST opened in the separator SP between the positive electrode PE and the negative electrode NE.
  • the separator that separates the positive electrode and the negative electrode is made of a resin film, and the slit portion ST as shown in FIG. 3 is not formed in the separator.
  • the separator of the comparative example is a sheet formed by stretching a resin film
  • the resin film has a three-dimensional network structure, and a lot of very small pores are opened in the resin film.
  • the pore diameter of the pores is several tens to several hundreds nm and is very small. Since the resin film has a three-dimensional network structure, the pores do not penetrate linearly from the front surface to the back surface of the separator.
  • lithium ions move between the electrodes through the pores.
  • the lithium ion battery cannot move linearly in the separator, but moves while meandering in the maze-like pores in the resin film having a three-dimensional network structure. For this reason, there is a problem that the internal resistance of the lithium ion battery increases due to the fact that the linear movement of lithium ions is hindered.
  • the three-dimensional network structure of the separator is changed when lithium ions move. Since it becomes an obstacle, it is disadvantageous in terms of diffusing lithium ions.
  • the pore diameter is very small as described above, the area in which lithium ions can move between the electrodes is small, which also causes the internal resistance of the lithium ion battery to increase.
  • the positive electrode or negative electrode active material of the lithium ion battery is fixed by a binder and is in close contact with an electrode plate such as a positive electrode plate or a negative electrode plate. In some cases, particles of the material may fall off the electrode plate.
  • the average diameter of the holes formed by processing the separator smaller than the average diameter of the active material, it is possible to prevent the active material from passing through the holes of the separator. Thereby, it is possible to prevent the occurrence of a short circuit between the electrodes due to the dropping of the active material.
  • the shape of the opening of the hole of the separator is considered to be, for example, a circle.
  • the average diameter of the pores of the separator is smaller than the average diameter of the active material, the area where lithium ions can move between the electrodes is small, so that the internal resistance of the lithium ion battery can be effectively reduced. Have difficulty.
  • the separator SP1 and the separator SP2 are provided with slit portions ST extending in one direction.
  • the size of the width W1 in the short direction of the slit part ST is less than the average particle diameter of a plurality of particles constituting the positive electrode active material PAS and the negative electrode active material NAS. Therefore, it is possible to prevent the particles of the positive electrode active material PAS or the negative electrode active material NAS, which have been peeled off, from passing through the slit portions ST opened in the separators SP1 and SP2, and therefore, between the electrodes due to the loss of the active material. The occurrence of a short circuit can be prevented. Thereby, the reliability of a lithium ion battery can be improved and the lifetime of a lithium ion battery can be extended.
  • the average diameter of the slit portion ST is very large compared to the diameter of the pores formed in the three-dimensional network structure constituting the separators SP1 and SP2.
  • the size of the length L1 of the slit part ST is equal to or larger than the average particle diameter of a plurality of particles constituting the positive electrode active material PAS and the negative electrode active material NAS. That is, the average diameter of the slit part ST is not less than the average particle diameter of the plurality of particles constituting the positive electrode active material PAS and the negative electrode active material NAS. Therefore, compared with the case where the average diameter of the hole part formed in the separator is smaller than the average diameter of an active material, the area which can move a lithium ion between electrodes can be expanded significantly.
  • the slit portion ST linearly penetrates from the front surface to the back surface of each of the separators SP1 and SP2 in the thickness direction of the separators SP1 and SP2. Therefore, since lithium ions can move linearly between the electrodes, the internal resistance of the lithium ion battery can be greatly reduced. Therefore, the performance of the lithium ion battery can be improved.
  • the separators SP1 and SP2 are made of a resin film having a three-dimensional network structure, and have pores in the gaps of the network structure. For this reason, when charging / discharging the lithium ion battery, lithium ions move between the electrodes through the pores as well as through the slit portions ST. For this reason, the internal resistance of a lithium ion battery can be reduced compared with the case where the slit part ST is provided in the film which does not have a three-dimensional network structure. Therefore, the performance of the lithium ion battery can be improved.
  • the above-described slit portion is provided in the separator to improve the diffusibility of lithium ions in the separator, thereby suppressing a short circuit due to the dropping of the active material.
  • FIG. 7 is a bird's-eye view illustrating the method for manufacturing the lithium ion battery of the present embodiment.
  • 8 to 11 are schematic diagrams for explaining a method of manufacturing the lithium ion battery according to the present embodiment.
  • a positive electrode sheet PEL constituting the lithium ion battery of the present embodiment is formed.
  • a positive electrode active material PAS made of lithium cobalt oxide, carbon as a conductive additive, and a binder (binder) are mixed.
  • a slurry is prepared from a solution obtained by dissolving the mixture thus formed in N-methylpyrrolidone (NMP), and the slurry is applied to the positive electrode plate PEP and dried, so that the electrode material film PEF containing the positive electrode active material PAS is formed.
  • NMP N-methylpyrrolidone
  • the electrode material film PEF is in contact with the positive electrode plate PEP so as to cover each of the surface of the positive electrode plate PEP and the back surface opposite to the front surface.
  • the binder (binder) with the positive electrode plate PEP is made of, for example, polyvinylidene fluoride.
  • the positive electrode active material PAS is composed of a plurality of particles, and the average particle size of these particles is, for example, 10 ⁇ m.
  • the positive electrode sheet PEL formed as described above is pressurized to increase the density of the positive electrode active material PAS applied to the positive electrode plate PEP and smooth the surface. Moreover, after application
  • the negative electrode sheet NEL which comprises the lithium ion battery of this Embodiment is formed.
  • a negative electrode active material NAS made of a carbon material (carbon material), carbon as a conductive additive, and a binder (binder) are mixed.
  • a slurry is prepared from a solution in which the mixture thus formed is dissolved in N-methylpyrrolidone (NMP), and the slurry is applied to the negative electrode plate NEP and dried, whereby the electrode material film NEF containing the negative electrode active material NAS is formed.
  • NMP N-methylpyrrolidone
  • the electrode material film NEF is in contact with the negative electrode plate NEP so as to cover each of the surface of the negative electrode plate NEP and the back surface opposite to the surface.
  • the binder (binder) with the negative electrode plate NEP is made of, for example, polyvinylidene fluoride.
  • the negative electrode active material NAS is composed of a plurality of particles, and the average particle size of these particles is, for example, 10 ⁇ m.
  • the negative electrode sheet NEL formed as described above is pressurized to increase the density of the negative electrode active material NAS applied to the negative electrode plate NEP and to smooth the surface. Moreover, after application
  • the positive electrode sheet PEL and the negative electrode sheet NEL formed as described above are prepared, and further, separators SP1 and SP2 are prepared. Thereafter, an electrode winding body constituting a lithium ion battery is formed by winding the sheet NEL positive electrode sheet, the separator, and the negative electrode sheet NEL.
  • the electrode winding body WRF (see FIG. 4) is formed by sequentially superposing the positive electrode sheet PEL, the separator SP1, the negative electrode sheet NEL, and the separator SP2, and this laminated sheet is formed as shown in FIG. It is formed by winding.
  • Separator SP1 and separator SP2 are used to insulate positive electrode sheet PEL and negative electrode sheet NEL.
  • a resin film containing polyolefin resin, polyester, polyimide, polyamide, cellulose, or the like can be used as a material for the separators SP1 and SP2.
  • the positive electrode current collecting tab PTAB formed on the positive electrode sheet PEL and the negative electrode current collecting tab NTAB formed on the negative electrode sheet NEL are arranged on the opposite sides in the Y direction. Further, before winding as described above, a plurality of slit portions ST are formed in each of the separator SP1 and the separator SP2 as described later with reference to FIG.
  • a plurality of slit portions ST are arranged in the short direction (Y direction) of the separator SP1 and the separator SP2. Further, the slit portion ST penetrates from the front surface to the back surface of the separator SP1 and the separator SP2.
  • the width W1 in the Y direction of the slit part ST is less than the average particle diameter of the positive electrode active material PAS and the negative electrode active material NAS, and is 9 ⁇ m, for example.
  • the length L1 in the longitudinal direction (X direction) of the slit part ST is not less than the average particle diameter of the positive electrode active material PAS and the negative electrode active material NAS.
  • the electrode winding body WRF is formed by winding the positive electrode sheet PEL, the separator SP1, the negative electrode sheet NEL, and the separator SP2 around the shaft core CR.
  • the positive electrode sheet PEL from the positive electrode roll PELR, the negative electrode sheet NEL from the negative electrode roll NELR, and the separator SP1 and the separator SP2 from the separator roll SPR are respectively rolled out, and these four sheets are After being stacked while being conveyed via the guide roller GRL, the electrode winding body WRF is formed by winding.
  • the separator SP1 and the separator SP2 are conveyed from the separator roll SPR to the slit forming unit STM before being wound.
  • a slitter blade SCT1 made of a material such as stainless steel, carbon steel, high-speed steel, cemented carbide, ceramic, sapphire, or diamond is disposed.
  • a plurality of cutting edges are provided on the surface of the slitter blade SCT1 and facing the surfaces of the separators SP1 and SP2 so as to be aligned in the short direction (Y direction) of the separators SP1 and SP2.
  • the width of each cutting edge of the slitter blade SCT1 in the Y direction is less than the average particle diameter of the positive or negative active material particles, and is, for example, 9 ⁇ m.
  • the slitter blade SCT1 is pressed against the respective surfaces of the separator SP1 and the separator SP2 while conveying the separator SP1 and the separator SP2 via the guide roller GRL. Thereby, a plurality of slit portions ST extending along the conveying direction of the separator SP1 and the separator SP2 are formed side by side in the Y direction.
  • the slitter blade SCT1 may be either rotating or fixed.
  • a laminated sheet in which the positive electrode sheet PEL and the negative electrode sheet NEL and the separators SP1 and SP2 in which the slit portions ST are opened can be wound. After winding the laminated sheet from several tens of cm to several m, the laminated sheet is cut with a cutter blade CT. Thereby, the electrode winding body WRF is formed.
  • the positive electrode current collecting tab PTAB protruding from the upper end of the electrode winding body WRF is connected to the positive electrode current collecting ring PR.
  • the negative electrode current collecting tab NTAB protruding from the lower end of the electrode winding body WRF is connected to the negative electrode current collecting ring NR.
  • the connection of the positive electrode current collector tab PTAB to the positive electrode current collector ring PR and the connection of the negative electrode current collector tab NTAB to the negative electrode current collector ring NR are performed by, for example, ultrasonic welding.
  • the electrode winding body WRF is inserted into the outer can CS.
  • the exterior can CS is processed and the groove
  • the groove DT is provided to fix the electrode winding body WRF inserted in the outer can CS so as not to move in the vertical direction.
  • electrolyte EL is injected into the exterior can CS into which the electrode winding body WRF is inserted. Thereby, the electrode winding body WRF is immersed in the electrolytic solution EL. Then, the lithium ion battery in this Embodiment can be manufactured by sealing the upper part of the armored can CS with the cap CP.
  • the separator SP1 and the separator SP2 are provided with slit portions ST extending in one direction. Since the size of the width W1 in the short direction of the slit part ST is less than the average particle diameter of the plurality of particles constituting the positive electrode active material PAS and the negative electrode active material NAS, a short circuit between the electrodes due to the dropping of the active material Can be prevented. Thereby, the reliability of a lithium ion battery can be improved and the lifetime of a lithium ion battery can be extended.
  • the average diameter of the slit part ST is not less than the average particle diameter of the plurality of particles constituting the positive electrode active material PAS and the negative electrode active material NAS, the average diameter of the holes formed in the separator is larger than the average diameter of the active material. Compared to a small case, the area in which lithium ions can move between the electrodes can be greatly increased.
  • the slit portion ST linearly penetrates from the front surface to the back surface of each of the separators SP1 and SP2 in the thickness direction of the separators SP1 and SP2, lithium ions move linearly between the electrodes. Is possible. Therefore, since the internal resistance of the lithium ion battery can be greatly reduced, the performance of the lithium ion battery can be improved.
  • the separators SP1 and SP2 are made of a resin film having a three-dimensional network structure, and have pores in the gaps of the network structure. For this reason, the internal resistance of a lithium ion battery can be reduced compared with the case where the slit part ST is provided in the film which does not have a three-dimensional network structure. For this reason, the performance of a lithium ion battery can be improved.
  • the extending direction of the slit portions ST in the separators SP1 and SP2 is matched with the direction in which the separators SP1 and SP2 are pulled in the winding step, that is, the longitudinal direction (X direction).
  • a plurality of holes having an average diameter less than the average diameter of the active material are opened in the separator.
  • a plurality of microneedles are attached to the surface of the roller, and the roller is pressed against the separator while rotating the roller according to the transport speed of the separator. It is conceivable to open the hole.
  • the slitter blade SCT1 is made of a material such as stainless steel, carbon steel, high-speed steel, cemented carbide, ceramic, sapphire, or diamond, and is stronger than microneedles (see FIG. 7). Is used to form the slit portion ST (see FIG. 4). For this reason, it is not necessary to delay the conveying speed of the separators SP1 and SP2, and the possibility of damage to the slitter blade SCT1 is small. Therefore, the manufacturing cost of the lithium ion battery can be reduced.
  • the above-described slit portion is provided in the separator to improve the diffusibility of lithium ions in the separator, thereby suppressing a short circuit due to the dropping of the active material.
  • FIG. 12 is a schematic view showing a laminated structure of a laminated body constituting the lithium ion battery of the present embodiment.
  • FIG. 13 is an overhead view showing a wound body constituting the lithium ion battery of the present embodiment.
  • the present embodiment is characterized in that a slit portion is formed intermittently (intermittently or discontinuously) in the separator using a slitter blade having an uneven edge.
  • the electrode winding body WRF (see FIG. 13) is formed by winding the positive electrode sheet PEL, the separator SP1, the negative electrode sheet NEL, and the separator SP2 in an overlapping manner.
  • a plurality of slit portions ST extending in the extending direction (X direction) of the separators SP1 and SP2 are arranged side by side in the X direction.
  • the shape of each slit portion ST is a rectangle, but the shape may be a polygon such as a trapezoid or a hexagon or an ellipse.
  • the width W1 in the short direction of the slit part ST is less than the average particle diameter of the positive electrode active material PAS and the negative electrode active material NAS, for example, 9 ⁇ m. Further, the length L2 in the longitudinal direction of each slit part ST is equal to or larger than the average particle diameter of the positive electrode active material PAS and the negative electrode active material NAS, and is, for example, 5 cm. Moreover, the width W3 between the slit parts ST adjacent in the X direction is, for example, 1 cm. Further, a width W2 between the slit portions ST adjacent in the Y direction is, for example, 1 cm.
  • the electrode wound body WRF is formed by winding the positive electrode sheet PEL, the separator SP1, the negative electrode sheet NEL, and the separator SP2 around the shaft core CR in an overlapped state.
  • the structure of the lithium ion battery of the present embodiment is the same as that of the first embodiment except for the aspect of the slit part ST.
  • the present embodiment is different from the first embodiment in that a plurality of slit portions ST extending in the X direction are arranged in the X direction in each of the separators SP1 and SP2. . Even if the slit portions ST are intermittently arranged in this way, the same effect as in the first embodiment can be obtained. Moreover, since the slit part ST is intermittently formed in each separator SP1, SP2, the mechanical strength in the longitudinal direction of the separators SP1, SP2 can be improved. Thereby, the reliability of a lithium ion battery can be improved.
  • FIG. 14 is a schematic diagram showing a method for manufacturing a lithium ion battery according to an embodiment of the present invention.
  • the manufacturing process of the lithium ion battery of the present embodiment is the same as the manufacturing process described in the first embodiment, except that the slitter blade SCT2 (see FIG. 14) is used to form the slit portion. That is, as shown in FIG. 13, the electrode winding body WRF is formed by winding the positive electrode sheet PEL, the separator SP1, the negative electrode sheet NEL, and the separator SP2 on the axis CR in a state where they are sequentially stacked.
  • the electrode winding body WRF is formed by winding in an overlapping manner.
  • each of the separators SP1 and SP2 is conveyed from the separator roll SPR to the slit forming portion STM before being wound.
  • a slitter blade SCT2 made of a material such as stainless steel, carbon steel, high-speed steel, cemented carbide, ceramic, sapphire or diamond is disposed.
  • the slitter blade SCT2 rotates corresponding to the transport speed of the separators SP1 and SP2 transported into the slit forming part STM.
  • the width of a plurality of cutting edges attached to the surface of the slitter blade SCT2 and the width in the direction along the rotation axis of the slitter blade SCT2 is less than the average particle diameter of the positive or negative active material particles.
  • the width of the cutting edge in the same direction is, for example, 9 ⁇ m.
  • the surface of the slitter blade SCT2 has a plurality of cutting edges arranged in the rotation direction of the slitter blade SCT2, the surface of the slitter blade SCT2 including the plurality of cutting edges is uneven.
  • the slitter blade is pressed against each of the separators SP1 and SP2 conveyed via the guide roller GRL. Thereby, slit part ST extended along the conveyance direction of separator SP1, SP2 is formed in each of separator SP1, SP2 intermittently (intermittently).
  • the slit portions ST can be intermittently formed along the longitudinal direction of the separators SP1 and SP2. Thereby, the same effect as the first embodiment can be obtained.
  • the mechanical strength in the longitudinal direction of the separator can be improved by intermittently arranging the slit portions ST in the X direction. Therefore, in the winding process described with reference to FIG. 14, even when tension is applied in the transport direction, the transport speed can be increased and productivity can be improved.
  • the wound type lithium ion battery has been described as an example.
  • the technical idea of the present invention is not limited to the wound type lithium ion battery, and includes a positive electrode, a negative electrode, And it can apply widely to an electrical storage device (for example, a battery or a capacitor etc.) provided with the separator which isolate
  • the present invention can be widely used in, for example, a manufacturing industry for manufacturing a battery typified by a lithium ion battery.
  • the present invention is effective when applied to a battery represented by a lithium ion battery.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Secondary Cells (AREA)

Abstract

La présente invention permet d'améliorer la sortie d'une pile au lithium-ion, et d'empêcher l'apparition d'un court-circuitage entre les électrodes positive et négative, provoqué par le délogement du matériau actif d'électrode. Un moyen de réalisation de l'invention consiste en une pile au lithium-ion comprenant une électrode positive, une électrode négative, ainsi qu'un séparateur pour séparer les électrodes, une section de fente étant formée qui s'étend dans le sens longitudinal du séparateur, cette section de fente étant une rainure passant de la surface avant à la surface arrière du séparateur. La largeur de la section de fente dans le sens court est inférieure au diamètre moyen du matériau actif, et la longueur dans le sens long est égale ou supérieure au diamètre moyen du matériau actif.
PCT/JP2014/079298 2014-11-05 2014-11-05 Pile au lithium-ion et son procédé de fabrication Ceased WO2016071967A1 (fr)

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PCT/JP2014/079298 WO2016071967A1 (fr) 2014-11-05 2014-11-05 Pile au lithium-ion et son procédé de fabrication

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000331666A (ja) * 1999-05-19 2000-11-30 Nec Corp セパレータ、これを備えた電池用組立体及び電池
JP2001068085A (ja) * 1999-08-27 2001-03-16 Shin Kobe Electric Mach Co Ltd 電 池
JP2005100899A (ja) * 2003-09-26 2005-04-14 Sony Corp 非水電解質二次電池
JP2006019146A (ja) * 2004-07-01 2006-01-19 Tomoegawa Paper Co Ltd 電子部品用セパレータ及びその製造方法
WO2009078159A1 (fr) * 2007-12-14 2009-06-25 Panasonic Corporation Batterie secondaire à électrolyte non aqueux et procédé de fabrication associé
JP2010009918A (ja) * 2008-06-26 2010-01-14 Toyota Central R&D Labs Inc リチウムイオン二次電池
JP2011054555A (ja) * 2009-09-02 2011-03-17 Samsung Sdi Co Ltd 電極群及びこれを適用した２次電池
JP2011159518A (ja) * 2010-02-02 2011-08-18 Toyota Motor Corp 電池及び電池の製造方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000331666A (ja) * 1999-05-19 2000-11-30 Nec Corp セパレータ、これを備えた電池用組立体及び電池
JP2001068085A (ja) * 1999-08-27 2001-03-16 Shin Kobe Electric Mach Co Ltd 電 池
JP2005100899A (ja) * 2003-09-26 2005-04-14 Sony Corp 非水電解質二次電池
JP2006019146A (ja) * 2004-07-01 2006-01-19 Tomoegawa Paper Co Ltd 電子部品用セパレータ及びその製造方法
WO2009078159A1 (fr) * 2007-12-14 2009-06-25 Panasonic Corporation Batterie secondaire à électrolyte non aqueux et procédé de fabrication associé
JP2010009918A (ja) * 2008-06-26 2010-01-14 Toyota Central R&D Labs Inc リチウムイオン二次電池
JP2011054555A (ja) * 2009-09-02 2011-03-17 Samsung Sdi Co Ltd 電極群及びこれを適用した２次電池
JP2011159518A (ja) * 2010-02-02 2011-08-18 Toyota Motor Corp 電池及び電池の製造方法

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