Charge control apparatus for battery pack which uses rate of change of battery temperature adjusted by correction factor

• US 5,652,500 A
• Filed: 11/06/1995
• Issued: 07/29/1997
• Est. Priority Date: 11/08/1994
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Watanabe, Yuichi, Kadouchi, Eiji, Kinoshita, Megumi, Ito, Noboru, Takata, Kanji
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US08/554,116
• Time in Patent Office: 631 Days
• Field of Search: 320/6, 320/15, 320/31, 320/35, 320/36
• US Class Current: 320/150
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/633 characterised by algorithms, flow charts, software details or the like
• CPC Class Codes: H01M 10/635 based on ambient temperature
• CPC Class Codes: H01M 10/6563 with forced flow, e.g. by blowers
• CPC Class Codes: H01M 10/66 Heat-exchange relationships between the cells and other systems, e.g. central heating systems or fuel cells
• CPC Class Codes: H01M 10/667 the system being an electronic component, e.g. a CPU, an inverter or a capacitor
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack is charged while being cooled by passing forced air therethrough. During charging, battery temperature and air temperature of air exhausted from the battery modules by the forced air cooling process are measured, and the difference between the battery temperature and the air temperature is calculated. The difference is added to an amount of change of the battery temperature per unit time to obtain a rate of change of battery temperature. When the rate of change exceeds a predetermined value, charging of the battery pack is controlled. In this manner, the battery temperature rise is correctly detected so that the battery pack can be fully charged without being damaged.

Claims

1. A charge control apparatus for a battery pack, the battery pack comprising a series assembly of a plurality of battery modules which are charged while being cooled by passing forced air therethrough, said apparatus comprising:

a battery temperature sensor for detecting a battery temperature of at least one of said battery modules;

an air temperature sensor for detecting an air temperature of air exhausted from said battery modules by the forced air cooling process;

temperature measuring means for measuring the battery temperature and the air temperature based on outputs of said battery temperature sensor and said air temperature sensor;

correction means for adding a correction amount based on a difference between the battery temperature and the air temperature to an amount of change of the battery temperature per unit time, to obtain a rate of change of the battery temperature;

rate-of-change judging means for generating a predetermined output when the rate of change exceeds a first predetermined value; and

a charge apparatus which receives said predetermined output and controls charging of said battery pack.

2. A charge control apparatus for a battery pack according to claim 1, wherein said apparatus further comprises temperature difference judging means for generating an output to stop said charge apparatus when an absolute value of a difference between the battery temperature and the air temperature is greater than a second predetermined value.

3. A charge control apparatus for a battery pack according to claim 1, wherein said apparatus further comprises air-temperature upper-limit judging means for generating an output to stop said charge apparatus when the air temperature is equal to or higher than a third predetermined value.

4. A charge control apparatus for a battery pack according to claim 1, wherein said apparatus further comprises air temperature change judging means for generating an output to stop said charge apparatus when an amount of change of the air temperature per unit time is greater than a fourth predetermined value.

5. A charge control apparatus for a battery pack according to claim 1, wherein said apparatus further comprises elapsed time judging means for suppressing an operation of said correction means and said rate-of-change judging means until a lapse of time from a start of charging reaches a predetermined time.

6. A charge control apparatus for a battery pack, the battery pack comprising a series assembly of a plurality of battery modules which are charged while being cooled by passing forced air therethrough, said apparatus comprising:

a first battery temperature sensor for detecting a battery temperature of at least one of said battery modules which does not easily radiate heat in said battery pack;

a second battery temperature sensor for detecting a battery temperature of at least one of said battery modules which easily radiates heat in said battery pack;

an air temperature sensor for detecting an air temperature of air exhausted from said battery modules by the forced air cooling process;

temperature measuring means for measuring the battery temperature and the air temperature based on at least one of outputs of said first and second battery temperature sensors and an output of said air temperature sensor;

sensor selection means for selectively outputting, on the basis of the air temperature, one of the outputs of said first and second battery temperature sensors, said selected output being supplied to said temperature measuring means;

correction means for adding a correction amount based on a difference between the battery temperature and the air temperature to an amount of change of the battery temperature per unit time, to obtain a rate of change of the battery temperature;

rate-of-change judging means for generating a predetermined output when the rate of change exceeds a predetermined value; and

a charge apparatus which receives said predetermined output and controls charging of said battery pack.