Nonaqueous electrolyte secondary battery

• US 5,053,297 A
• Filed: 04/02/1990
• Issued: 10/01/1991
• Est. Priority Date: 04/03/1989
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kato, Hisayuki, Yamahira, Takayuki, Anzai, Masanori
• Primary Examiner(s): Kalafut, Stephen J.
• Application Number:
  US07/502,679
• Time in Patent Office: 547 Days
• Field of Search: 429/194, 429/218, 429/223
• US Class Current: 429/231.3
• 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 2004/028 Positive electrodes
• CPC Class Codes: H01M 4/36 Selection of substances as active materials, active masses, active liquids
• 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 4/525 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: Y02E 60/10 Energy storage using batteries

Abstract

A nonaqueous electrolyte secondary battery is disclosed, which comprises an anode having a carbonaceous material as the anode active material which permits lithium to be doped and undoped and a current collector, a cathode having a lithium compound as the cathode active material which permits lithium to be doped and undoped, and a nonaqueous electrolyte. The cathode active material contains the primary active material of a first lithium compound having the potential which is more "noble" than the potential of the current collector and the auxiliary active material of a second lithium compound having the potential which is more "base" than the potential of the current collector. The auxiliary active material works to avoid the dissolution of the anode current collector at the final stage of discharge.

Claims

1. A nonaqueous electrolyte secondary battery comprising an anode having a carbonaceous material as an anode active material which permits lithium to be doped and undoped and an anode current collector, a cathode having a lithium compound as a cathode active material which permits lithium to be doped and undoped, and a nonaqueous electrolyte, characterized in that said cathode active material contains a primary active material of a first lithium compound having a potential which is more "noble" than a potential of said anode current collector and an auxiliary active material of a second lithium compound having the potential which is more "base" than the potential of the current collector.

2. A nonaqueous electrolyte secondary battery according to claim 1, wherein said primary active material is Li_x Co_1-y Ni_y O₂ where 0<

x≦

1 and 0≦

y>

0.50.

3. A nonaqueous electrolyte secondary battery according to claim 2, wherein said primary active material is Li_x CoO₂.

4. A nonaqueous electrolyte secondary battery according to claim 1, wherein said auxiliary active material is complex oxide of lithium and molybdenum.

5. A nonaqueous electrolyte secondary battery according to claim 1, wherein said auxiliary active material is Li_x Co_1-y Ni_y O₂ where 0<

x≦

1 and 0.9<

y≦

1.0.

6. A nonaqueous electrolyte secondary battery according to claim 1, wherein an anode having said carbonaceous material and said anode collector and a cathode having said cathode active material are wound with a separator interposed between said anode and cathode.