LITHIUM ION SECONDARY BATTERY SYSTEM AND BATTERY PACK

• US 20120105010A1
• Filed: 03/16/2011
• Published: 05/03/2012
• Est. Priority Date: 05/17/2010
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kinoshita, Masahiro
• Application Number:
  US13/382,713
• Publication Number:
  US 20120105010A1
• Time in Patent Office: Days
• US Class Current: 320/136
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 10/615 Heating or keeping warm
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 10/63 Control systems charging or discharging in response to temperature H01M10/44 , H01M10/443; measurement of temperature H01M10/48 , H01M10/486
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A lithium ion secondary battery system includes: an assembled battery including a plurality of lithium ion secondary batteries; a SOC measuring unit for measuring the SOC of the lithium ion secondary battery, and a temperature sensing unit for sensing the temperature thereof; and a heating unit for heating the lithium ion secondary battery. When a SOC measured by the SOC measuring unit is lower than a preset SOC set in advance in association with discharge rate, and a temperature measured by the temperature sensing unit is lower than a preset temperature set in advance in association with discharge rate, then, a control unit sends a command to the heating unit to supply heat, so that the temperature of the lithium ion secondary battery becomes a predetermined temperature.

Claims

1. A lithium ion secondary battery system comprising:

an assembled battery comprising a plurality of lithium ion secondary batteries each provided with a positive electrode including olivine-based lithium composite phosphate;

a SOC measuring unit for measuring the SOC which indicates the state of charge of at least one of said lithium ion secondary batteries;

a temperature sensing unit for sensing the temperature of at least one of said lithium ion secondary batteries;

a heating unit for heating at least one of said lithium ion secondary batteries; and

a heating control unit for controlling said heating unit to heat said at least one of said lithium ion secondary batteries,

wherein, said heating control unit sends a command to heat said at least one of said lithium ion secondary batteries to a predetermined target temperature, when a measured SOC measured by said SOC measuring unit is lower than a preset SOC set in advance in association with discharge rate, and a sensed temperature sensed by said temperature sensing unit is lower than a preset temperature set in advance in association with said discharge rate.

2. The lithium ion secondary battery system in accordance with claim 1, wherein said preset SOC is 5 to 40% relative to a 100% SOC of a fully charged state of said at least one of said lithium ion secondary batteries.

3. The lithium ion secondary battery system in accordance with claim 1, wherein said preset temperature is 25 to 50°

C.

4. The lithium ion secondary battery system in accordance with claim 1, wherein said target temperature is 45 to 55°

C.

5. The lithium ion secondary battery system in accordance with claim 1, wherein said olivine-based lithium composite phosphate is represented by the general formula (I):

Li_xMe(PO_y)_z, where Me is at least one selected from the group consisting of Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, and B;

0<

x≦

2, 3≦

y≦

4, and 0.5<

z≦

1.5.

6. The lithium ion secondary battery system in accordance with claim 5, wherein said olivine-based lithium composite phosphate represented by the general formula (1) contains, as Me, two or more elements selected from said group, and 20 mol % or more of Me is Fe.

7. The lithium ion secondary battery system in accordance with claim 1, wherein said heating unit includes a resistor which generates heat by passing current therethrough.

8. The lithium ion secondary battery system in accordance with claim 1, wherein said heating unit uses an external heat source as the heat source.

9. The lithium ion secondary battery system in accordance with claim 8, said system being installed as a power source for driving a vehicle, wherein said external heat source is residual heat generated by driving the vehicle.

10. A battery pack comprising:

the lithium ion secondary battery system in accordance with claim 1; and

a charge/discharge control unit for controlling charge and discharge of said plurality of the lithium ion secondary batteries.