AQUEOUS PASTE FOR ELECTROCHEMICAL CELL, ELECTRODE PLATE FOR ELECTROCHEMICAL CELL OBTAINED BY APPLYING THE AQUEOUS PASTE, AND BATTERY COMPRISING THE ELECTRODE PLATE

• US 20160359169A1
• Filed: 08/19/2016
• Published: 12/08/2016
• Est. Priority Date: 11/18/2009
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.), Mitsui Chemicals Incorporated (Mitsui Chemicals)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.), Mitsui Chemicals Incorporated (Mitsui Chemicals)
• Inventors: ETOH, Akinori, MITATE, Takehito, NISHINAKA, Syumpei, MIYATA, Gen, NISHIMURA, Naoto, MATSUYAMA, Takahiro
• Application Number:
  US15/241,732
• Publication Number:
  US 20160359169A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C08J 2323/00 Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
• CPC Class Codes: C08J 3/05 from solid polymers
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 4/242 Hydrogen storage electrodes
• CPC Class Codes: H01M 4/26 Processes of manufacture
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: H01M 4/624 Electric conductive fillers
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The aqueous paste for an electrochemical cell of the present invention comprises an aqueous dispersion for an electrochemical cell that comprises an olefin copolymer (a); an active material; and a conductive assistant, wherein the olefin copolymer (a) has a weight average molecular weight of not less than 50,000 and is at least one kind selected from a random propylene copolymer (a-1) containing 50% by weight to less than 85% by weight of a structural unit derived from propylene; an acid-modified random propylene copolymer (a-2) obtained by modifying the copolymer (a-1) with an acid; and an ethylene-(meth)acrylic acid copolymer (a-3) containing 5% by weight to less than 25% by weight of a structural unit derived from (meth)acrylic acid.

Claims

1. A non-aqueous electrolyte secondary battery comprising a positive electrode plate for an electrochemical cell and a negative electrode plate for an electrochemical cell,

wherein the positive electrode plate for an electrochemical cell is obtained by applying an aqueous paste for an electrochemical cell (1),

wherein the aqueous paste for an electrochemical cell (1) comprises

an aqueous dispersion for an electrochemical cell (A) that comprises an olefin copolymer (a) being an ethylene-(meth)acrylic acid copolymer (a-3) having a weight average molecular weight, as determined by gel permeation chromatography (GPC), of not less than 50,000 (in terms of polystyrene) and containing 5% by weight to 25% by weight of a structural unit derived from (meth)acrylic acid;

an active material (B) that comprises olivine LiFePO₄ having a median diameter (D50), as measured by laser diffraction scattering method, of 0.5 to 9 μ

m and having a specific surface area of 5 to 30 m²/g, wherein the amount of the active material (B) applied on the positive electrode plate for an electrochemical cell is 4 to 90 mg/cm²; and

a conductive assistant (C),

wherein the negative electrode plate for an electrochemical cell is obtained by applying an aqueous paste for an electrochemical cell (2),

wherein the aqueous paste for an electrochemical cell (2) comprises

an aqueous dispersion for an electrochemical cell (A) that comprises an olefin copolymer (a) being at least one kind selected from a random propylene copolymer (a-1) having a weight average molecular weight, as determined by gel permeation chromatography (GPC), of from 50,000 to 100,000 (in terms of polystyrene) and containing 50% by weight to less than 85% by weight of a structural unit derived from propylene, an acid-modified random propylene copolymer (a-2) obtained by modifying the random propylene copolymer (a-1) with an acid, and an ethylene-(meth)acrylic acid copolymer (a-3) having a weight average molecular weight, as determined by gel permeation chromatography (GPC), of not less than 50,000 (in terms of polystyrene) and containing 5% by weight to less than 25% by weight of a structural unit derived from (meth)acrylic acid;

an active material (B) that comprises spherical natural graphite, wherein the amount of the active material (B) applied on the negative electrode plate for an electrochemical cell is 2 to 50 mg/cm²; and

a conductive assistant (C).

2. The non-aqueous electrolyte secondary battery according to claim 1,

wherein, in the aqueous paste for an electrochemical cell (1) or in the aqueous paste for an electrochemical cell (2), based on 100 parts by weight of the active material (B), the amount of a solid content of the aqueous dispersion (A) is 0.5 to 30 parts by weight, and the amount of the conductive assistant (C) is 0.1 to 20 parts by weight.

3. The non-aqueous electrolyte secondary battery according to claim 1,

wherein, in the aqueous paste for an electrochemical cell (1) or in the aqueous paste for an electrochemical cell (2), the aqueous dispersion (A) comprises at least one kind selected from a surfactant (x) and a viscosity modifier (y).

4. The non-aqueous electrolyte secondary battery according to claim 3,

wherein based on 100 parts by weight of a solid content of the olefin copolymer (a), the amount of a solid content of the surfactant (x) is 0 to 100 parts by weight, and the amount of a solid content of the viscosity modifier (y) is 10 to 100 parts by weight.

5. The non-aqueous electrolyte secondary battery according to claim 3,

wherein the viscosity modifier (y) is at least one kind selected from carboxymethyl cellulose, polyethylene oxide, a modified product of polyethylene oxide, polyvinyl alcohol and a modified product of polyvinyl alcohol.

6. The non-aqueous electrolyte secondary battery according to claim 1,

wherein the spherical natural graphite has a median diameter (D50), as measured by laser diffraction scattering method, of 15 to 20 μ

m.

7. The non-aqueous electrolyte secondary battery according to claim 6,

wherein the spherical natural graphite has a specific surface area of 2 to 5 m²/g.

8. The non-aqueous electrolyte secondary battery according to claim 1,

wherein, in the aqueous paste for an electrochemical cell (1) or in the aqueous paste for an electrochemical cell (2), the conductive assistant (C) is at least one kind selected from acetylene black and artificial graphite.

9. The non-aqueous electrolyte secondary battery according to claim 8,

wherein the conductive assistant (C) has a specific surface area of 2 to 80 m²/g.

10. The non-aqueous electrolyte secondary battery according to claim 8,

wherein the acetylene black has a median diameter (D50), as measured by laser diffraction scattering method, of 0.02 to 5 μ

m.

11. The non-aqueous electrolyte secondary battery according to claim 8,

wherein the artificial graphite has a median diameter (D50), as measured by laser diffraction scattering method, of 2 to 80 μ

m.

12. The non-aqueous electrolyte secondary battery according to claim 1,

wherein, in the positive electrode plate for an electrochemical cell or in the negative electrode plate for an electrochemical cell, the electrode plate has an electricity capacity of 0.5 to 18 mAh/cm².

13. The non-aqueous electrolyte secondary battery according to claim 1,

wherein, in the positive electrode plate for an electrochemical cell, the packing density of the active material applied on the positive electrode plate is 1.0 to 2.0 g/cm³.

14. The non-aqueous electrolyte secondary battery according to claim 1,

wherein, in the negative electrode plate for an electrochemical cell, the packing density of the active material applied on the negative electrode plate is 1.0 to 1.7 g/cm³.

15. The non-aqueous electrolyte secondary battery according to claim 1,

wherein the aqueous dispersion for an electrochemical cell (A) used in the negative electrode plate for an electrochemical cell further comprises an acid-modified olefin (co)polymer (a-4) having a weight average molecular weight, as determined by gel permeation chromatography (GPC), of less than 50,000 (in terms of polystyrene).

16. A household storage battery comprising the non-aqueous electrolyte secondary battery according to claim 1.