LITHIUM SECONDARY BATTERIES AND NONAQUEOUS ELECTROLYTE FOR USE IN THE SAME

• US 20150243936A1
• Filed: 03/17/2015
• Published: 08/27/2015
• Est. Priority Date: 10/20/2005
• Status: Abandoned Application

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: KATO, Ryoichi, KOTATO, Minoru, SUZUKI, Hitoshi, MIYAGI, Hidekazu, YOKOMIZO, Masakazu, UONO, Hiroyuki, MATSUMOTO, Hitoshi, SATOU, Tomohiro, NAKAJIMA, Takayuki, OSHIMA, Hiroyuki
• Application Number:
  US14/660,517
• Publication Number:
  US 20150243936A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 50/64 Constructional details of batteries specially adapted for electric vehicles
• 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 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• CPC Class Codes: H01M 2300/0034 Fluorinated solvents
• CPC Class Codes: H01M 2300/004 Three solvents
• CPC Class Codes: H01M 4/0428 Chemical vapour deposition
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/1391 : of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/1393 : of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/364 : as mixtures
• CPC Class Codes: H01M 4/485 : of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/505 : of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 : of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/583 : Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/587 : for inserting or intercalating light metals
• CPC Class Codes: H01M 50/119 : Metals
• CPC Class Codes: H01M 50/121 : Organic material
• CPC Class Codes: H01M 50/124 : having a layered structure
• CPC Class Codes: H01M 50/46 : Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries

Abstract

A lithium secondary battery comprising a battery case and an electrode group is provided. The electrode group comprises a positive electrode, a negative electrode, a microporous film separator and a nonaqueous electrolyte comprising a lithium salt. The electrode group and the nonaqueous electrolyte are held in the battery case and the electrodes each comprise a current collector and an active-material layer containing an active material capable of occluding/releasing a lithium ion. The nonaqueous electrolyte comprises a difluorophosphoric acid salt in an amount of 10 ppm or more of the whole nonaqueous electrolyte. The battery case comprises a casing material in which at least part of the battery inner side comprises a sheet formed from a thermoplastic resin and with which the electrode group can be enclosed by placing the electrode group in the casing material and heat sealing layers of the thermoplastic resin to each other.

Claims

1. (canceled)

2. A lithium secondary battery comprising:

a battery case; and

an electrode group, comprising;

a positive electrode,

a negative electrode,

a microporous film separator interposed between the positive electrode and the negative electrode; and

a nonaqueous electrolyte comprising a nonaqueous solvent and a lithium salt,

wherein

the electrode group and the nonaqueous electrolyte are held in the battery case,

and the positive electrode and the negative electrode each comprise a current collector and, formed thereon, an active-material layer containing an active material capable of occluding/releasing a lithium ion,

wherein

the nonaqueous electrolyte is a nonaqueous electrolyte which comprises a difluorophosphoric acid salt in an amount of 10 ppm or more of the whole nonaqueous electrolyte; and

the battery case comprises a casing material in which at least part of the battery inner side comprises a sheet formed from a thermoplastic resin and with which the electrode group can be enclosed by placing the electrode group in the casing material and heat sealing layers of the thermoplastic resin to each other.

3. The lithium secondary battery according to claim 2, wherein the content of the difluorophosphoric acid salt is from 0.01% by mass to 5% by mass.

4. The lithium secondary battery according to claim 2, wherein a proportion of the volume of the electrode group to the volume of the battery case of the lithium secondary battery which excludes any projection is 0.7 or lower.

5. The lithium secondary battery according to claim 2, wherein the shape of the battery case is a bottomed polygonal shape, wherein a proportion of double the area S₁ of the largest face of this battery case (product of the width and height of the outer dimensions excluding the terminal parts;

unit, cm²) to the thickness T (unit, cm) of the battery outer shape, i.e., the value of (2×

S₁/T), is 100 or larger.

6. The lithium secondary battery according to claim 2, which is a secondary battery having a multilayered electrode group, wherein in each of the positive electrode and the negative electrode, a ratio of the overall length L (unit, cm) of the periphery of the electrode to double the electrode area S₂ (unit, cm²), i.e., (L/(2×

S₂)), is 1 or smaller.

7. The lithium secondary battery according to claim 2, which is a secondary battery of a bottomed cylindrical shape having a wound electrode group, wherein a proportion of the length-direction dimension to the width-direction dimension in the positive electrode is from 15 to 200.

8. The lithium secondary battery according to claim 2, wherein an overall electrode area of the positive electrode is at least 15 times the surface area of the case of the lithium secondary battery.

9. The lithium secondary battery according to claim 2, wherein the microporous film separator has a property of closing pores upon heating and the battery case is made of a casing material in which at least part of the battery inner side comprises a sheet formed from a thermoplastic resin having a melting point higher than the pore closing initiation temperature of the microporous film separator.

10. The lithium secondary battery according to claim 2, wherein a casing material of the battery case comprises a multilayered sheet having an aluminum layer and a thermoplastic-resin layer laminated.

11. A battery assembly comprising five or more serially connected batteries which each are the lithium secondary battery according to claim 2.

12. A battery assembly comprising two or more connected batteries which each are the lithium secondary battery according to claim 2, wherein the battery assembly has a cooling mechanism for keeping the batteries at or below a certain temperature.

13. The lithium secondary battery according to claim 2, which is mounted on a vehicle and supplies power at least to the driving system of the vehicle.

14. The battery assembly according to claim 12, which is mounted on a vehicle and supplies power at least to the driving system of the vehicle.