WO2022195943A1 - 亜鉛二次電池 - Google Patents

亜鉛二次電池 Download PDF

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Publication number
WO2022195943A1
WO2022195943A1 PCT/JP2021/039085 JP2021039085W WO2022195943A1 WO 2022195943 A1 WO2022195943 A1 WO 2022195943A1 JP 2021039085 W JP2021039085 W JP 2021039085W WO 2022195943 A1 WO2022195943 A1 WO 2022195943A1
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Prior art keywords
negative electrode
secondary battery
zinc
positive electrode
ldh
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PCT/JP2021/039085
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English (en)
French (fr)
Japanese (ja)
Inventor
淳宣 松矢
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NGK Insulators Ltd
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NGK Insulators Ltd
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Priority to JP2023506729A priority Critical patent/JP7545569B2/ja
Publication of WO2022195943A1 publication Critical patent/WO2022195943A1/ja
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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
    • H01M10/24—Alkaline accumulators
    • H01M10/30—Nickel accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M12/00—Hybrid cells; Manufacture thereof
    • H01M12/08—Hybrid cells; Manufacture thereof composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/24—Electrodes for alkaline accumulators
    • H01M4/32—Nickel oxide or hydroxide electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/72—Grids
    • H01M4/74—Meshes or woven material; Expanded metal
    • 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
    • H01M50/431—Inorganic material
    • 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
    • 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
    • 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 zinc secondary batteries.
  • zinc secondary batteries such as nickel-zinc secondary batteries and air-zinc secondary batteries
  • metallic zinc deposits in the form of dendrites from the negative electrode during charging, and penetrates the pores of a separator such as a non-woven fabric to reach the positive electrode. known to cause short circuits. Short circuits caused by such zinc dendrites lead to shortening of repeated charge/discharge life.
  • Patent Document 1 International Publication No. 2013/118561 discloses providing an LDH separator between a positive electrode and a negative electrode in a nickel-zinc secondary battery.
  • Patent Document 2 International Publication No. 2016/076047 discloses a separator structure provided with an LDH separator fitted or joined to a resin outer frame, wherein the LDH separator is gas impermeable and and/or are disclosed to have such a high density that they are impermeable to water.
  • Patent Document 3 International Publication No. 2016/067884 discloses various methods for forming an LDH dense film on the surface of a porous substrate to obtain a composite material.
  • a starting material capable of providing starting points for LDH crystal growth is uniformly attached to a porous substrate, and the porous substrate is subjected to hydrothermal treatment in an aqueous raw material solution to form an LDH dense film on the surface of the porous substrate. It includes a step of forming
  • an LDH separator in which further densification is realized by roll-pressing a composite material of LDH/porous substrate produced through hydrothermal treatment.
  • Patent Document 4 International Publication No. 2019/124270
  • Patent Document 4 includes a polymer porous substrate and LDH filled in the porous substrate, and has a linear transmittance of 1% or more at a wavelength of 1000 nm.
  • An LDH separator is disclosed.
  • LDH-like compounds are known as hydroxides and/or oxides having a layered crystal structure similar to LDH, although they cannot be called LDH. It exhibits physical ion conduction properties.
  • Patent Document 5 International Publication No. 2020/255856 describes hydroxide ions containing a porous substrate and a layered double hydroxide (LDH)-like compound that closes the pores of the porous substrate.
  • LDH layered double hydroxide
  • a hydroxide and/or oxide of layered crystal structure, wherein the LDH-like compound comprises Mg and one or more elements including at least Ti selected from the group consisting of Ti, Y and Al. is disclosed.
  • This hydroxide ion-conducting separator is said to be superior to conventional LDH separators in alkali resistance and to more effectively suppress short circuits caused by zinc dendrites.
  • Patent Document 6 International Publication No. 2019/069760
  • Patent Document 7 International Publication No. 2019/077953
  • the entire negative electrode active material layer is covered or wrapped with a liquid retaining member and an LDH separator
  • a zinc secondary battery having a configuration in which a positive electrode active material layer is covered or wrapped with a liquid retaining member has been proposed.
  • a nonwoven fabric is used as the liquid retaining member.
  • a zinc secondary battery (especially a laminated battery thereof) capable of preventing the extension of zinc dendrites can be produced very simply and with high productivity by eliminating the need for complicated sealed bonding between the LDH separator and the battery container. It is said that it can be done.
  • the negative electrode layer in zinc secondary batteries as disclosed in Patent Documents 1 to 7 includes a negative electrode active material layer and a negative electrode current collector.
  • a metal plate having a plurality of or a large number of openings, such as expanded metal, punched metal, or metal mesh, is used as the negative electrode current collector.
  • the negative electrode active material layer 14a see FIG. 6A
  • ZnO layer the outer peripheral portion of the layer 14a
  • FIG. 6B As this shape change progresses, protrusions B such as burrs and burrs at the ends of the negative electrode current collector may be exposed, and the exposed protrusions B may cause a short circuit.
  • the present inventors have recently found that the negative electrode active material layer extends from the end of the positive electrode active material layer, and the positive electrode plate and the negative electrode plate are separated by the extension distance b from the positive electrode active material layer end of the negative electrode active material layer.
  • the knowledge that the risk of short circuit due to negative electrode shape change peculiar to zinc secondary batteries can be effectively reduced by configuring the battery so that the ratio (that is, b/a) to the separation distance a is 8 or more. Obtained.
  • an object of the present invention is to provide a zinc secondary battery that can effectively reduce the risk of short circuit due to negative electrode shape change even after repeated charge-discharge cycles.
  • a positive electrode plate including a positive electrode active material layer and a positive electrode current collector; a negative electrode active material layer containing at least one selected from the group consisting of zinc, zinc oxide, a zinc alloy and a zinc compound; a negative electrode plate including a negative electrode current collector provided in the a hydroxide ion conductive separator separating the positive electrode plate and the negative electrode plate so as to conduct hydroxide ions; an electrolyte; and the negative electrode active material layer extends from the end of the positive electrode active material layer by a predetermined distance b over all sides except for the portion extending as the current collecting tab in plan view is extended,
  • b/a which is a ratio of the extension distance b to the separation distance a in the plate thickness direction between the positive electrode plate and the negative electrode plate, is 8 or more.
  • FIG. 1 is a schematic cross-sectional view showing an example of a zinc secondary battery according to the present invention
  • FIG. FIG. 2 is a diagram schematically showing an example of an A-A′ line cross section of the zinc secondary battery shown in FIG. 1
  • FIG. 2 is a diagram schematically showing another example of the A-A′ line cross section of the zinc secondary battery shown in FIG. 1
  • FIG. 3 is a schematic cross-sectional view of a battery element for explaining a separation distance a in the plate thickness direction and an extension distance b between a positive electrode plate and a negative electrode plate.
  • FIG. 2 is a diagram conceptually showing (a) the initial state before the start of charge-discharge cycles and (b) the cross-sectional state of the battery element in the final state after repeated charge-discharge cycles in the zinc secondary battery of the present invention.
  • FIG. 2 is a diagram conceptually showing (a) an initial state before the start of charge-discharge cycles and (b) a cross-sectional state of a battery element in a final state after repeated charge-discharge cycles in a conventional zinc secondary battery.
  • the zinc secondary battery of the present invention is not particularly limited as long as it is a secondary battery using zinc as a negative electrode and using an alkaline electrolyte (typically an aqueous alkali metal hydroxide solution). Therefore, it can be a nickel-zinc secondary battery, a silver-zinc oxide secondary battery, a manganese-zinc oxide secondary battery, an air-zinc secondary battery, and various other alkaline zinc secondary batteries.
  • the positive electrode active material layer preferably contains nickel hydroxide and/or nickel oxyhydroxide, thereby making the zinc secondary battery a nickel-zinc secondary battery.
  • the positive electrode active material layer may be the air electrode layer, whereby the zinc secondary battery may form a zinc air secondary battery.
  • FIGS. 1 and 2 show one aspect of the zinc secondary battery according to the present invention.
  • the zinc secondary battery 10 shown in FIGS. 1 and 2 comprises a battery element 11 in a closed container 20, the battery element 11 comprising a positive plate 12, a negative plate 14, and a hydroxide ion conducting separator. 16 and a unit cell 10 a containing an electrolyte 18 .
  • the cathode plate 12 includes a cathode active material layer 12a and a cathode current collector (not shown).
  • the negative plate 14 includes a negative active material layer 14a and a negative current collector 14b.
  • the negative electrode active material layer 14a contains at least one selected from the group consisting of zinc, zinc oxide, zinc alloys and zinc compounds.
  • the negative electrode current collector 14b is provided inside and/or on the surface of the negative electrode active material layer 14a except for the portion extending as the current collecting tab 14c.
  • the hydroxide ion conducting separator 16 separates the positive plate 12 and the negative plate 14 in a hydroxide ion conducting manner. Then, as shown in an enlarged cross section in FIG. 4, the positive electrode active material layer 12a extends along all the sides of the negative electrode active material layer 14a in plan view, excluding the portion extending as the current collecting tab 14c. and a ratio b/a of the extension distance b to the separation distance a in the plate thickness direction between the positive electrode plate 12 and the negative electrode plate 14 is 8 or more.
  • the negative electrode active material layer 14a is extended from the end of the positive electrode active material layer 12a, and the positive electrode plate 12 and the negative electrode plate are separated by the extension distance b of the negative electrode active material layer 14a from the end of the positive electrode active material layer 12a.
  • the cell is constructed so that the ratio of 14 to the separation distance a (ie, b/a) is 8 or greater.
  • a metal plate having a plurality or a large number of openings such as expanded metal, punching metal, metal mesh, etc.
  • the negative electrode current collector is used as the negative electrode current collector.
  • a shape change occurs in which the shape of the negative electrode changes.
  • the negative electrode active material layer 14a see FIG. 6A
  • FIG. 6B shows A phenomenon in which the outer peripheral portion of the layer 14a is unevenly eroded and lost.
  • protrusions B such as burrs and burrs at the ends of the negative electrode current collector may be exposed, and the exposed protrusions B may cause a short circuit.
  • the negative electrode active material layer 14a is made larger than the positive electrode active material layer 12a so as to protrude from the edge of the positive electrode active material layer 12a so as to satisfy the above conditions.
  • the shape change of the negative electrode active material layer 14a progresses from the outer peripheral portion toward the inner portion. Therefore, the negative electrode active material remains in a frame shape at the end of the negative electrode active material layer 14a that does not face the positive electrode active material layer 12a.
  • the protrusions B such as burrs and burrs of 14b remaining buried, the protrusions B are not exposed. In this way, a short circuit due to the protrusion B can be prevented.
  • b/a which is the ratio of the extension distance b to the separation distance a in the plate thickness direction between the positive electrode plate 12 and the negative electrode plate 14, is 8 or more, preferably 8 to 26, more preferably 8 to 21, and even more preferably. is in the range of 8-16.
  • the separation distance a between the positive electrode plate 12 and the negative electrode plate 14 in the plate thickness direction is the sum of the hydroxide ion conductive separator 16 and the liquid retaining member 17 (if present) interposed between the positive electrode plate 12 and the negative electrode plate 14. thickness. Therefore, the separation distance a can be calculated from the thickness of the hydroxide ion conductive separator 16 and/or the liquid retaining member 17 .
  • the positive electrode plate 12 includes a positive electrode active material layer 12a.
  • the positive electrode active material forming the positive electrode active material layer 12a is not particularly limited, and may be appropriately selected from known positive electrode materials according to the type of zinc secondary battery. For example, in the case of a nickel-zinc secondary battery, a positive electrode containing nickel hydroxide and/or nickel oxyhydroxide may be used. Alternatively, in the case of a zinc-air secondary battery, the air electrode may be used as the positive electrode.
  • the positive plate 12 further includes a positive current collector (not shown), which preferably has a positive current collector tab 12b extending from an end (eg, top end) of the positive plate 12 .
  • Preferred examples of the positive electrode current collector include nickel porous substrates such as foamed nickel plates.
  • a positive electrode plate composed of a positive electrode/positive current collector can be preferably produced by uniformly applying a paste containing an electrode active material such as nickel hydroxide onto a nickel porous substrate and drying the paste.
  • a paste containing an electrode active material such as nickel hydroxide
  • the positive electrode plate 12 shown in FIG. 2 includes a positive electrode current collector (for example, foamed nickel), it is not shown. This is because, in the case of the nickel-zinc secondary battery, the positive electrode current collector is integrated with the positive electrode active material, and thus the positive electrode current collector cannot be depicted separately.
  • the zinc secondary battery 10 preferably further includes a positive electrode current collector plate connected to the tip of the positive electrode current collector tab 12b, and more preferably, a plurality of positive electrode current collector tabs 12b are connected to one positive electrode current collector plate. . By doing so, current collection can be performed with good space efficiency with a simple configuration, and connection to the positive electrode terminal 26 is also facilitated. Alternatively, the positive current collecting plate itself may be used as the positive terminal 26 .
  • the positive electrode plate 12 may contain at least one additive selected from the group consisting of silver compounds, manganese compounds, and titanium compounds, whereby the positive electrode reaction absorbs hydrogen gas generated by the self-discharge reaction. can promote Moreover, the positive electrode plate 12 may further contain cobalt. Cobalt is preferably contained in the positive electrode plate 12 in the form of cobalt oxyhydroxide. In the positive electrode plate 12, cobalt functions as a conductive aid, thereby contributing to an improvement in charge/discharge capacity.
  • the negative electrode plate 14 includes a negative electrode active material layer 14a.
  • the negative electrode active material forming the negative electrode active material layer 14a contains at least one selected from the group consisting of zinc, zinc oxide, zinc alloys, and zinc compounds. Zinc may be contained in any form of zinc metal, zinc compound, and zinc alloy as long as it has electrochemical activity suitable for the negative electrode. Preferred examples of the negative electrode material include zinc oxide, zinc metal, calcium zincate, etc., and a mixture of zinc metal and zinc oxide is more preferred.
  • the negative electrode active material may be configured in a gel form, or may be mixed with the electrolytic solution 18 to form a negative electrode mixture. For example, a gelled negative electrode can be easily obtained by adding an electrolytic solution and a thickener to the negative electrode active material. Examples of the thickener include polyvinyl alcohol, polyacrylate, CMC, alginic acid, etc. Polyacrylic acid is preferable because of its excellent chemical resistance to strong alkali.
  • the zinc alloy it is possible to use a zinc alloy that does not contain mercury and lead, which is known as a zinc-free zinc alloy.
  • a zinc alloy containing 0.01 to 0.1% by mass of indium, 0.005 to 0.02% by mass of bismuth, and 0.0035 to 0.015% by mass of aluminum has the effect of suppressing hydrogen gas generation. Therefore, it is preferable.
  • Indium and bismuth are particularly advantageous in terms of improving discharge performance.
  • the use of a zinc alloy for the negative electrode slows down the rate of self-dissolution in an alkaline electrolyte, thereby suppressing the generation of hydrogen gas and improving safety.
  • the shape of the negative electrode material is not particularly limited, it is preferably powdered, which increases the surface area and enables high-current discharge.
  • the average particle size of the preferred negative electrode material is in the range of 3 to 100 ⁇ m in minor axis. It is easy to mix uniformly with the agent, and is easy to handle during battery assembly.
  • the negative electrode plate 14 includes a negative electrode current collector 14b provided inside and/or on the surface of the negative electrode active material layer 14a (excluding the portion extending as the negative electrode current collecting tab 14c). That is, the negative electrode active material layer 14a may be arranged on both sides of the negative electrode current collector 14b, or the negative electrode active material layer 14a may be arranged only on one side of the negative electrode current collector 14b. good.
  • the negative electrode plate 14 further includes a negative current collector 14b, and the negative electrode current collector 14b preferably has a negative current collector tab 14c extending from an edge (eg, top end) of the negative electrode plate 14 .
  • the negative electrode current collecting tab 14c is preferably provided at a position not overlapping the positive electrode current collecting tab 12b.
  • the zinc secondary battery 10 preferably further includes a negative electrode current collector plate connected to the tip of the negative electrode current collector tab 14c, and more preferably a plurality of negative electrode current collector tabs 14c are connected to one negative electrode current collector plate. .
  • a negative electrode current collector plate connected to the tip of the negative electrode current collector tab 14c, and more preferably a plurality of negative electrode current collector tabs 14c are connected to one negative electrode current collector plate.
  • a metal plate having a plurality (or a large number) of openings as the negative electrode current collector 14b.
  • Preferred examples of such a negative electrode current collector 14b include expanded metal, punched metal, metal mesh, and combinations thereof, more preferably copper expanded metal, copper punched metal, and combinations thereof, especially Copper expanded metal is preferred.
  • a mixture comprising zinc oxide powder and/or zinc powder and, if desired, a binder (for example, polytetrafluoroethylene particles) is applied onto a copper expanded metal to form a negative electrode composed of a negative electrode/a negative electrode current collector. Plates can be preferably made.
  • the expanded metal is a mesh-like metal plate obtained by expanding a metal plate with zigzag cuts by an expander and forming the cuts into a diamond shape or a tortoiseshell shape.
  • a perforated metal is also called a perforated metal, and is made by punching holes in a metal plate.
  • a metal mesh is a metal product with a wire mesh structure, and is different from expanded metal and perforated metal.
  • the hydroxide ion-conducting separator 16 is provided so as to separate the positive electrode plate 12 and the negative electrode plate 14 so that hydroxide ions can be conducted.
  • the positive electrode plate 12 may be covered or wrapped with a hydroxide ion conductive separator 16 .
  • the negative electrode plate 14 may be covered or wrapped with a hydroxide ion conducting separator 16 .
  • the hydroxide ion-conducting separator 16 is not particularly limited as long as it can separate the positive electrode plate 12 and the negative electrode plate 14 so that hydroxide ions can be conducted, but typically includes a hydroxide ion-conducting solid electrolyte. , is a separator that allows hydroxide ions to pass through exclusively by utilizing hydroxide ion conductivity.
  • Preferred hydroxide ion-conducting solid electrolytes are layered double hydroxides (LDH) and/or LDH-like compounds. Therefore, hydroxide ion conducting separator 16 is preferably an LDH separator.
  • LDH separator refers to a separator containing LDH and/or LDH-like compounds, which selectively removes hydroxide ions by exclusively utilizing the hydroxide ion conductivity of LDH and/or LDH-like compounds.
  • LDH-like compounds are hydroxides and/or oxides of layered crystal structure similar to LDH, although they may not be called LDH, and can be said to be equivalents of LDH.
  • LDH can be interpreted as including not only LDH but also LDH-like compounds.
  • the LDH separator is preferably composited with the porous substrate.
  • the LDH separator further includes a porous substrate, and the LDH and/or the LDH-like compound are combined with the porous substrate in a form in which the pores of the porous substrate are filled.
  • preferred LDH separators are those in which LDH and/or LDH-like compounds are porous so as to exhibit hydroxide ion conductivity and gas impermeability (and thus function as LDH separators exhibiting hydroxide ion conductivity). block the pores of the base material.
  • the porous substrate is preferably made of a polymeric material, and it is particularly preferable that the LDH is incorporated throughout the entire thickness direction of the porous substrate made of polymeric material.
  • LDH separators as disclosed in Patent Documents 1-7 can be used.
  • the thickness of the LDH separator is preferably 5-100 ⁇ m, more preferably 5-80 ⁇ m, still more preferably 5-60 ⁇ m, particularly preferably 5-40 ⁇ m.
  • the positive electrode plate 12 and the negative electrode plate 14 are interposed between the positive electrode plate 12 and the negative electrode plate 14. Then, the positive electrode plate 12 and/or the negative electrode plate 14 are preferably covered or wrapped with the liquid retaining member 17 .
  • a simple configuration in which the liquid retaining member 17 is arranged on one surface side of the positive electrode plate 12 or the negative electrode plate 14 may be employed. In any case, by interposing the liquid retaining member 17, the electrolytic solution 18 can be evenly present between the positive electrode plate 12 and/or the negative electrode plate 14 and the hydroxide ion conductive separator 16.
  • the liquid holding member 17 is not particularly limited as long as it can hold the electrolytic solution 18, but is preferably a sheet-like member.
  • Preferred examples of the liquid-retaining member 17 include nonwoven fabrics, water-absorbing resins, liquid-retaining resins, porous sheets, and various spacers, but nonwoven fabrics are particularly preferable in that a negative electrode structure with good performance can be produced at low cost. be.
  • the liquid retaining member 17 or the nonwoven fabric preferably has a thickness of 10 to 200 ⁇ m, more preferably 20 to 200 ⁇ m, still more preferably 20 to 150 ⁇ m, particularly preferably 20 to 100 ⁇ m, most preferably 20 ⁇ m. ⁇ 60 ⁇ m.
  • a sufficient amount of the electrolytic solution 18 can be retained in the liquid retaining member 17 while keeping the overall size of the positive electrode structure and/or the negative electrode structure compact without waste.
  • the positive electrode plate 12 and/or the negative electrode plate 14 are covered or wrapped with the liquid retaining member 17 and/or the separator 16, their outer edges (sides from which the positive electrode current collecting tab 12b and the negative electrode current collecting tab 14c extend) except) preferably closed.
  • the liquid-retaining member 17 and/or the separator 16 has a closed outer edge by bending the liquid-retaining member 17 and/or the separator 16 or by sealing the liquid-retaining members 17 and/or the separators 16 together.
  • Preferred examples of sealing techniques include adhesives, heat welding, ultrasonic welding, adhesive tapes, sealing tapes, and combinations thereof.
  • an LDH separator containing a porous substrate made of a polymeric material has the advantage of being easy to bend because of its flexibility.
  • Thermal welding and ultrasonic welding may be performed using a commercially available heat sealer or the like.
  • the outer peripheral portion of the liquid retaining member 17 should be sandwiched between the LDH separators forming the outer peripheral portion. It is preferable to perform heat welding and ultrasonic welding by using the same method because more effective sealing can be performed.
  • commercially available adhesives, adhesive tapes and sealing tapes may be used, but those containing an alkali-resistant resin are preferable in order to prevent deterioration in an alkaline electrolyte.
  • examples of preferable adhesives include epoxy resin adhesives, natural resin adhesives, modified olefin resin adhesives, and modified silicone resin adhesives. It is more preferable because it is particularly excellent in alkalinity.
  • a product example of the epoxy resin-based adhesive includes the epoxy adhesive Hysol (registered trademark) (manufactured by Henkel).
  • the outer edge of one side, which is the upper end of the separator 16 is open.
  • This open-top configuration makes it possible to deal with the problem of overcharging in nickel-zinc batteries and the like. That is, when a nickel-zinc battery or the like is overcharged, oxygen (O 2 ) may be generated in the positive electrode plate 12, but the LDH separator has a high degree of denseness that substantially allows only hydroxide ions to pass. Impervious to O2 .
  • O 2 can escape to the upper side of the positive electrode plate 12 and be sent to the negative electrode plate 14 side through the upper open portion, thereby O 2 can oxidize Zn in the negative electrode active material and return it to ZnO.
  • overcharge resistance can be improved by using the open-top battery element 11 in a sealed zinc secondary battery.
  • a ventilation hole may be opened after sealing the outer edge of one side, which is the upper end of the LDH separator, or a part of the outer edge may be unsealed so that a ventilation hole is formed during sealing. good.
  • the electrolytic solution 18 preferably contains an aqueous alkali metal hydroxide solution. Electrolyte 18 is only shown locally in FIGS. 2 and 3 because it permeates the entire positive plate 12 and negative plate 14 .
  • alkali metal hydroxides include potassium hydroxide, sodium hydroxide, lithium hydroxide and ammonium hydroxide, with potassium hydroxide being more preferred.
  • Zinc compounds such as zinc oxide and zinc hydroxide may be added to the electrolytic solution in order to suppress self-dissolution of zinc and/or zinc oxide.
  • the electrolyte may be mixed with the positive electrode active material and/or the negative electrode active material to exist in the form of a positive electrode mixture and/or a negative electrode mixture.
  • the electrolyte may be gelled to prevent leakage of the electrolyte.
  • the gelling agent it is desirable to use a polymer that absorbs the solvent of the electrolytic solution and swells, and polymers such as polyethylene oxide, polyvinyl alcohol and polyacrylamide, and starch are used.
  • the battery element 11 includes a plurality of positive electrode plates 12, a plurality of negative electrode plates 14, and a plurality of separators 16.
  • the unit of positive electrode plate 12/separator 16/negative plate 14 is is preferably in the form of a positive/negative electrode laminate in which are laminated so as to be repeated. That is, it is preferable that the zinc secondary battery 10 has a plurality of unit cells 10a, so that the plurality of unit cells 10a as a whole form a multi-layer cell. This is a so-called assembled battery or laminated battery configuration, and is advantageous in that a high voltage and a large current can be obtained.
  • the closed container 20 is preferably made of resin.
  • the resin constituting the sealed container 20 is preferably a resin having resistance to alkali metal hydroxides such as potassium hydroxide, more preferably polyolefin resin, ABS resin, or modified polyphenylene ether, and still more preferably ABS resin. or modified polyphenylene ether.
  • the closed container 20 has an upper lid 20a.
  • the sealed container 20 (for example, the upper lid 20a) may have a pressure release valve for releasing gas.
  • a case group in which two or more airtight containers 20 are arranged may be accommodated in the outer frame to constitute a battery module.
  • the LDH separator may contain an LDH-like compound.
  • LDH-like compounds are (a) is a hydroxide and/or oxide having a layered crystal structure containing Mg and one or more elements containing at least Ti selected from the group consisting of Ti, Y and Al, or (b) (i ) Ti, Y, and optionally Al and/or Mg, and (ii) an additional element M that is at least one selected from the group consisting of In, Bi, Ca, Sr, and Ba.
  • (c) is a hydroxide and/or oxide, or (c) is a hydroxide and/or oxide of layered crystal structure comprising Mg, Ti, Y, and optionally Al and/or In, said (c) in the LDH-like compound is present in the form of a mixture with In(OH) 3 .
  • the LDH-like compound is a hydroxide having a layered crystal structure containing Mg and at least one element containing at least Ti selected from the group consisting of Ti, Y and Al. and/or an oxide.
  • Typical LDH-like compounds are therefore complex hydroxides and/or complex oxides of Mg, Ti, optionally Y and optionally Al.
  • the LDH-like compound preferably does not contain Ni.
  • the LDH-like compound may further contain Zn and/or K. By doing so, the ionic conductivity of the LDH separator can be further improved.
  • LDH-like compounds can be identified by X-ray diffraction. Specifically, when X-ray diffraction is performed on the surface of the LDH separator, the A peak derived from an LDH-like compound is detected in the range.
  • LDH is a material with an alternating layer structure in which exchangeable anions and H 2 O are present as intermediate layers between stacked hydroxide elementary layers.
  • a peak due to the crystal structure of LDH that is, the (003) peak of LDH
  • a peak due to the crystal structure of LDH that is, the (003) peak of LDH
  • the interlayer distance of the layered crystal structure can be determined by Bragg's equation using 2 ⁇ corresponding to the peak derived from the LDH-like compound in X-ray diffraction.
  • the interlayer distance of the layered crystal structure constituting the LDH-like compound thus determined is typically 0.883 to 1.8 nm, more typically 0.883 to 1.3 nm.
  • the atomic ratio of Mg/(Mg+Ti+Y+Al) in the LDH-like compound determined by energy dispersive X-ray spectroscopy (EDS) is preferably 0.03 to 0.25, It is more preferably 0.05 to 0.2.
  • the atomic ratio of Ti/(Mg+Ti+Y+Al) in the LDH-like compound is preferably 0.40 to 0.97, more preferably 0.47 to 0.94.
  • the atomic ratio of Y/(Mg+Ti+Y+Al) in the LDH-like compound is preferably 0 to 0.45, more preferably 0 to 0.37.
  • the atomic ratio of Al/(Mg+Ti+Y+Al) in the LDH-like compound is preferably 0 to 0.05, more preferably 0 to 0.03. Within the above range, the alkali resistance is even more excellent, and the effect of suppressing short circuits caused by zinc dendrites (that is, dendrite resistance) can be more effectively realized.
  • LDH separators have the general formula: M 2+ 1 ⁇ x M 3+ x (OH) 2 A n ⁇ x/n ⁇ mH 2 O (wherein M 2+ is a divalent cation, M 3+ is a trivalent cation, A n- is an n-valent anion, n is an integer of 1 or more, x is 0.1 to 0.4, and m is 0 or more.
  • M 2+ is a divalent cation
  • M 3+ is a trivalent cation
  • a n- is an n-valent anion
  • n is an integer of 1 or more
  • x is 0.1 to 0.4
  • m is 0 or more.
  • the atomic ratios in LDH-like compounds generally deviate from the general formula for LDH. Therefore, it can be said that the LDH-like compound in this aspect generally has a composition ratio (atomic ratio) different from conventional LDH.
  • an EDS analyzer eg, X-act, manufactured by Oxford Instruments
  • X-act e.g., X-act, manufactured by Oxford Instruments
  • the LDH-like compound has a layered crystal structure comprising (i) Ti, Y and optionally Al and/or Mg and (ii) an additional element M It can be hydroxide and/or oxide. Accordingly, typical LDH-like compounds are complex hydroxides and/or complex oxides of Ti, Y, additional element M, optionally Al and optionally Mg.
  • the additive element M is In, Bi, Ca, Sr, Ba, or a combination thereof.
  • the atomic ratio of Ti/(Mg+Al+Ti+Y+M) in the LDH-like compound determined by energy dispersive X-ray spectroscopy (EDS) is preferably 0.50 to 0.85, It is more preferably 0.56 to 0.81.
  • the atomic ratio of Y/(Mg+Al+Ti+Y+M) in the LDH-like compound is preferably 0.03-0.20, more preferably 0.07-0.15.
  • the atomic ratio of M/(Mg+Al+Ti+Y+M) in the LDH-like compound is preferably 0.03-0.35, more preferably 0.03-0.32.
  • the atomic ratio of Mg/(Mg+Al+Ti+Y+M) in the LDH-like compound is preferably 0 to 0.10, more preferably 0 to 0.02.
  • the atomic ratio of Al/(Mg+Al+Ti+Y+M) in the LDH-like compound is preferably 0 to 0.05, more preferably 0 to 0.04.
  • LDH separators have the general formula: M 2+ 1 ⁇ x M 3+ x (OH) 2 A n ⁇ x/n ⁇ mH 2 O (wherein M 2+ is a divalent cation, M 3+ is a trivalent cation, A n- is an n-valent anion, n is an integer of 1 or more, x is 0.1 to 0.4, and m is 0 or more.
  • M 2+ is a divalent cation
  • M 3+ is a trivalent cation
  • a n- is an n-valent anion
  • n is an integer of 1 or more
  • x is 0.1 to 0.4
  • m is 0 or more.
  • the atomic ratios in LDH-like compounds generally deviate from the general formula for LDH. Therefore, it can be said that the LDH-like compound in this aspect generally has a composition ratio (atomic ratio) different from conventional LDH.
  • an EDS analyzer eg, X-act, manufactured by Oxford Instruments
  • X-act e.g., X-act, manufactured by Oxford Instruments
  • the LDH-like compound is a hydroxide and/or oxide of layered crystal structure comprising Mg, Ti, Y and optionally Al and/or In.
  • the LDH-like compound may be present in the form of a mixture with In(OH) 3 .
  • the LDH-like compounds of this embodiment are hydroxides and/or oxides of layered crystal structure containing Mg, Ti, Y, and optionally Al and/or In.
  • Typical LDH-like compounds are therefore complex hydroxides and/or complex oxides of Mg, Ti, Y, optionally Al and optionally In.
  • the LDH-like compound In that can be contained in the LDH-like compound is not only intentionally added to the LDH-like compound, but also inevitably mixed into the LDH-like compound due to the formation of In(OH) 3 or the like. can be anything. Although the above elements may be replaced with other elements or ions to the extent that the basic properties of the LDH-like compound are not impaired, the LDH-like compound preferably does not contain Ni.
  • LDH separators have the general formula: M 2+ 1 ⁇ x M 3+ x (OH) 2 A n ⁇ x/n ⁇ mH 2 O (wherein M 2+ is a divalent cation, M 3+ is a trivalent cation, A n- is an n-valent anion, n is an integer of 1 or more, x is 0.1 to 0.4, and m is 0 or more.
  • M 2+ is a divalent cation
  • M 3+ is a trivalent cation
  • a n- is an n-valent anion
  • n is an integer of 1 or more
  • x is 0.1 to 0.4
  • m is 0 or more.
  • the atomic ratios in LDH-like compounds generally deviate from the above general formula for LDH. Therefore, it can be said that the LDH-like compound in this aspect generally has a composition ratio (atomic ratio) different from conventional LDH.
  • the mixture according to embodiment (c) above contains not only LDH-like compounds but also In(OH) 3 (typically composed of LDH-like compounds and In(OH) 3 ).
  • the inclusion of In(OH) 3 can effectively improve the alkali resistance and dendrite resistance of the LDH separator.
  • the content of In(OH) 3 in the mixture is not particularly limited, and is preferably an amount that can improve the alkali resistance and dendrite resistance without substantially impairing the hydroxide ion conductivity of the LDH separator.
  • In(OH) 3 may have a cubic crystal structure, or may have a structure in which In(OH) 3 crystals are surrounded by an LDH-like compound.
  • In(OH) 3 can be identified by X-ray diffraction.
  • Example 1 Fabrication of Nickel-Zinc Secondary Battery
  • a positive electrode plate, a negative electrode plate, an LDH separator, a non-woven fabric, an airtight container, and an electrolytic solution shown below were prepared.
  • - Positive electrode plate A positive electrode paste containing nickel hydroxide and a binder is filled in the pores of foamed nickel and dried, number of sheets: 13,
  • ⁇ Negative electrode plate A paste containing ZnO powder, metal Zn powder, polytetrafluoroethylene (PTFE) and propylene glycol is pressure-bonded to a current collector (copper expanded metal), number: 14
  • ⁇ LDH separator polyethylene microporous film Ni-Al-Ti-LDH (layered double hydroxide) is precipitated in the pores and on the surface of the by hydrothermal synthesis and roll-pressed, thickness: 0.009 mm ⁇ Non-woven fabric: made of polyethylene, thickness: 0.130 mm ⁇ Sealed container: Housing made of modified polyphenylene ether resin
  • the negative electrode plate was wrapped with the nonwoven fabric and the LDH separator in order, and the three sides other than the upper end were thermally fused and sealed to form a negative electrode structure with an open top.
  • a total of 27 positive electrode plates and negative electrode structures prepared in this manner were put in a sealed container so as to be alternately positioned.
  • the positive electrode current collector tab extending upward from the positive electrode current collector was connected to the positive electrode terminal, while the negative electrode current collector tab extended upward from the negative electrode current collector was connected to the negative electrode terminal, and the lid was closed.
  • the negative electrode active material layer extends by 2.0 mm from the end of the positive electrode active material layer over all sides (that is, three sides) excluding the portion extending as the current collecting tab when viewed from above.
  • the electrolyte was added through the injection port, and the electrolyte was sufficiently permeated into the positive electrode plate and the negative electrode plate by vacuuming or the like, and then the injection port was closed. Thus, a multilayer cell type nickel-zinc secondary battery was obtained.
  • Example 2 The negative electrode active material layer was made to extend from the end of the positive electrode active material layer by 3.5 mm over all sides (that is, three sides) excluding the portion extending as the current collecting tab when viewed from above.
  • a battery was produced and evaluated in the same manner as in Example 1, except for the above.
  • Example 3 Fabrication of Nickel-Zinc Secondary Battery
  • a positive electrode plate, a negative electrode plate, an LDH separator, a non-woven fabric, an airtight container, and an electrolytic solution shown below were prepared.
  • - Positive electrode plate A positive electrode paste containing nickel hydroxide and a binder is filled in the pores of foamed nickel and dried, number of sheets: 12,
  • ⁇ Negative electrode plate A paste containing ZnO powder, metal Zn powder, polytetrafluoroethylene (PTFE) and propylene glycol is pressure-bonded to a current collector (copper expanded metal), number: 13
  • ⁇ LDH separator polyethylene microporous film
  • Ni-Al-Ti-LDH (layered double hydroxide) is precipitated in the pores and on the surface of the by hydrothermal synthesis and roll-pressed, thickness: 0.03 mm ⁇ Non-woven fabric: made of polypropylene, thickness: 0.10 mm ⁇ Sealed container: Housing made of modified polyphenylene
  • a horizontal tab type nickel-zinc secondary battery in which the positive electrode current collecting tab and the negative electrode current collecting tab extend laterally in opposite directions as disclosed in Patent Document 7 is assembled.
  • rice field. Specifically, the positive electrode plate is wrapped in a non-woven fabric, and two sides (excluding the upper end side and the side overlapping the positive electrode current collecting tab) are thermally fused and sealed to form a positive electrode structure with an open top, while the negative electrode plate is formed. was successively wrapped with a non-woven fabric and an LDH separator (excluding the upper edge and the side overlapping the negative electrode current collecting tab), and two sides were thermally fused and sealed to form a negative electrode structure with an open top.
  • a total of 25 positive electrode structures and negative electrode structures prepared in this manner were put in a sealed container so as to be alternately positioned.
  • the positive electrode current collector tab extending laterally from the positive electrode current collector was connected to the positive electrode terminal, while the negative electrode current collecting tab extending laterally from the negative electrode current collector was connected to the negative electrode terminal, and the lid was closed.
  • the negative electrode active material layer extends by 2.0 mm from the end of the positive electrode active material layer over all sides (that is, three sides) excluding the portion extending as the current collecting tab when viewed from above. configured as
  • the electrolyte was added through the injection port, and the electrolyte was sufficiently permeated into the positive electrode plate and the negative electrode plate by vacuuming or the like, and then the injection port was closed.
  • a multilayer cell type nickel-zinc secondary battery was obtained.
  • Example 4 The negative electrode active material layer was made to extend from the end of the positive electrode active material layer by 3.5 mm over all sides (that is, three sides) excluding the portion extending as the current collecting tab when viewed from above.
  • a battery was fabricated and evaluated in the same manner as in Example 3, except for the above.
  • Example 5 (Comparison) The negative electrode active material layer was made to extend from the end of the positive electrode active material layer by 1.0 mm over all sides (that is, three sides) excluding the portion extending as the current collecting tab when viewed from above. A battery was produced and evaluated in the same manner as in Example 1, except for the above.
  • Example 6 (Comparison) The negative electrode active material layer was made to extend from the end of the positive electrode active material layer by 1.0 mm over all sides (that is, three sides) excluding the portion extending as the current collecting tab when viewed from above. A battery was fabricated and evaluated in the same manner as in Example 3, except for the above.

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WO2018105178A1 (ja) * 2016-12-07 2018-06-14 日本碍子株式会社 電極／セパレータ積層体及びそれを備えたニッケル亜鉛電池
WO2019077953A1 (ja) * 2017-10-20 2019-04-25 日本碍子株式会社 亜鉛二次電池

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018105178A1 (ja) * 2016-12-07 2018-06-14 日本碍子株式会社 電極／セパレータ積層体及びそれを備えたニッケル亜鉛電池
WO2019077953A1 (ja) * 2017-10-20 2019-04-25 日本碍子株式会社 亜鉛二次電池

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