Lithium ion secondary battery

• US 20070048596A1
• Filed: 08/14/2006
• Published: 03/01/2007
• Est. Priority Date: 08/25/2005
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Hasegawa, Masaki, Bito, Yasuhiko
• Application Number:
  US11/503,300
• Publication Number:
  US 20070048596A1
• Time in Patent Office: Days
• US Class Current: 429/62
• 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 10/36 Accumulators not provided for in groups H01M10/05-H01M10/34
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• 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 4/134 Electrodes based on metals, Si or alloys
• 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: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A lithium ion secondary battery that offers high thermal stability. The lithium ion secondary battery includes a positive electrode capable of absorbing and desorbing lithium ions, a negative electrode capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte, wherein a difference ΔT between a temperature T₁ and a temperature T₂ is equal to 50° C. or greater, where the T₁ is a temperature at which the heat generation rate of the positive electrode in a charged state reaches the maximum, and the T₂ is a temperature at which the heat generation rate of the negative electrode in a charged state reaches the maximum.

Claims

1. A lithium ion secondary battery comprising a positive electrode capable of absorbing and desorbing lithium ions, a negative electrode capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte,

wherein a difference Δ

T between a temperature T₁ and a temperature T₂ is equal to 50°

C. or greater, where said T₁ is a temperature at which the heat generation rate of said positive electrode in a charged state reaches the maximum, and said T₂ is a temperature at which the heat generation rate of said negative electrode in a charged state reaches the maximum.

2. The lithium ion secondary battery in accordance with claim 1, wherein said temperature T₁ is not less than 215°

C.

3. The lithium ion secondary battery in accordance with claim 1,

wherein said positive electrode comprises a positive electrode active material, a conductive material and a binder, and

said positive electrode active material is represented by the formula Li_xCo_1-y-zNi_yM_zO₂, where 0.95≦

x≦

1.1, 0≦

y≦

0.9, 0≦

z≦

0.5, and M is at least one element selected from the group consisting of Al, Mn, Mg, Ti, V, Fe, Cu and Zn.

4. The lithium ion secondary battery in accordance with claim 1,

wherein said negative electrode comprises a negative electrode active material and a binder, and

said negative electrode active material comprises at least one selected from the group consisting of carbon material, Si, Si alloy, Si oxide, Sn, Sn alloy and Sn oxide.

5. A charging system for a lithium ion secondary battery comprising a lithium ion secondary battery and a charger for charging said lithium ion secondary battery,

said lithium ion secondary battery comprising a positive electrode capable of absorbing and desorbing lithium ions, a negative electrode capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte,

wherein said charger has a function to terminate charging when said lithium ion secondary battery is at a state of charge of not less than 90% relative to its rated capacity, and

a difference Δ

T between a temperature T₁ and a temperature T₂ is equal to 50°

C. or greater, where said T₁ is a temperature at which the heat generation rate of the positive electrode contained in said lithium ion secondary battery at a state of charge of not less than 90% relative to its rated capacity reaches the maximum, and said T₂ is a temperature at which the heat generation rate of the negative electrode contained in said lithium ion secondary battery at a state of charge of not less than 90% relative to its rated capacity reaches the maximum.