Battery state diagnostic apparatus for battery set and battery module charger/discharger

• US 6,072,300 A
• Filed: 11/12/1998
• Issued: 06/06/2000
• Est. Priority Date: 11/14/1997
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Tsuji, Tadashi
• Primary Examiner(s): Tso, Edward H.
• Assistant Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US09/190,173
• Time in Patent Office: 572 Days
• Field of Search: 320/116, 320/132, 320/DIG. 21, 324/429, 324/430, 324/433
• US Class Current: 320/116
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A diagnostic apparatus for determining a battery charge status of a battery set, includes a no-load voltage calculating section for detecting no-load voltage VCn of cells; a first judging section for determining whether a battery state of each of the cells C is normal or abnormal based on the cell no-load voltage VCn calculated by the no-load voltage calculating section; and a second judging section for determining that a battery module including the cell determined to be abnormal by the first judging section is an abnormal battery module which is necessary to be exchanged. Further, the battery state diagnostic apparatus may also include a third judging section for determining a battery set is an abnormal battery set which is necessary to be exchanged when the number of battery modules determined to be abnormal is equal to or greater than a predetermined number, and calculating section for calculating the average voltage value of a plurality of battery modules determined to be normal based on the cell no-load voltage VCn.

Claims

1. A diagnostic apparatus for diagnosing a state of charge of a battery set including a plurality of battery modules each having a plurality of cells, comprising:

a no-load voltage calculating section for calculating no-load voltage of the cell;

a first judging section for determining whether a state of charge of each of the cells is normal or abnormal based on the no-load voltage of the cell calculated by the no-load voltage calculating section; and

a second judging section for determining that a battery module including a cell judged to be abnormal by the first judging section is an abnormal battery module which is required to be replaced.

2. A diagnostic apparatus according to claim 1, further comprising a third judging section for determining that, when a number of battery modules judged to be abnormal by the second judging section is equal to or more than a predetermined number, the battery set is abnormal.

3. A diagnostic apparatus according to claim 1, further comprising a calculating section for calculating an average voltage value of the battery modules determined to be normal, based on the no-load voltage of the cell calculated by the no-load voltage calculating section.

4. An electric car provided with a battery set including a plurality of battery modules having a plurality of cells, the electric car comprising a diagnostic apparatus for diagnosing battery charge status comprising:

a no-load voltage calculating section for calculating no-load voltage of the cell;

a first judging section for determining whether a state of charge of each of the cells is normal or abnormal based on the no-load voltage of the cell calculated by the no-load voltage calculating section; and

a second judging section for determining that a battery module including a cell judged to be abnormal by the first judging section is an abnormal battery which requires replacement.

5. A module charger/discharger for adjusting a voltage of a replacement battery module which is used to replace an abnormal battery module in a battery set including a plurality of battery modules having a plurality of cells, the module charger/discharger comprising:

an average voltage calculating section for calculating the average voltage value of a plurality of battery modules judged to be normal by a battery diagnostic apparatus, wherein the replacement battery module is charged or discharged such that the voltage of the replacement battery module assumes the average voltage value calculated by the average voltage calculating section;

the battery diagnostic apparatus comprising;

a no-load voltage calculating section for calculating a no-load voltage of each of the cells;

a first judging section for judging whether a state of charge of each of the cells is normal or abnormal based on the no-load voltage of the cell calculated by the no-load voltage calculating section; and

a second judging section for judging that a battery module including a cell judged to be abnormal by the first judging section is an abnormal battery module which requires replacement.

6. A module charger/discharger for adjusting a voltage of a replacement battery module which is used to replace an abnormal battery module of a battery set including a plurality of battery modules having a plurality of cells, wherein the replacement battery module is charged or discharged such that the voltage of the replacement battery module assumes the average voltage value calculated by a battery state diagnostic apparatus comprising:

a no-load voltage calculating section for calculating no-load voltage of the cell;

a first judging section for judging whether a battery state of each of the cells is normal or abnormal based on the no-load voltage of the cell calculated by the no-load voltage calculating section; and

a second judging section for judging that a battery module including a cell judged to be abnormal by the first judging section is an abnormal battery module which requires replacement.

7. A diagnostic apparatus for a battery set including a plurality of battery modules having a plurality of cells, comprising:

an internal resistance calculating section for calculating internal resistance of each of the cells;

a first judging section for judging whether a state of charge of each of the cells is normal or abnormal based on the internal resistance of the cells calculated by the internal resistance calculating section; and

a second judging section for judging that a battery module including a cell determined to be abnormal by the first judging section is an abnormal battery module which requires replacement.

8. A diagnostic apparatus according to claim 7, further comprising a third judging section for determining that, when the number of module batteries determined to be abnormal by the second judging section is equal to or more than a predetermined number, the battery set is abnormal.

9. A diagnostic apparatus according to claim 7, further comprising a calculating section for calculating an average internal resistance value of the battery modules determined to be normal, based on the internal resistance of the cell calculated by the internal resistance calculating section.

10. An electric car provided with a battery set including a plurality of battery modules each having a plurality of cells, the electric car comprising a diagnostic apparatus for diagnosing the state of the battery modules comprising:

an internal resistance calculating section for calculating internal resistance of each of the cells;

a first judging section for judging whether a state of charge of each of the cells is normal or abnormal based on the internal resistance of the cells calculated by the internal resistance calculating section; and

a second judging section for judging that a battery module including a cell determined to be abnormal by the first judging section is an abnormal battery module which requires replacement.

11. A module charger/discharger for adjusting a voltage of a replacement battery module which is used to replace an abnormal battery module in a battery set including a plurality of battery modules which each have a plurality of cells, the module charger/discharger comprising:

an average voltage calculating section for calculating the average voltage value of a plurality of battery modules determined to be normal by a battery diagnostic apparatus, wherein the replacement battery module is charged or discharged such that the voltage of the replacement battery module assumes the average voltage value calculated by the average voltage calculating section;

the battery diagnostic apparatus comprising;

an internal resistance calculating section for calculating internal resistance of each of the cells;

a first judging section for determining whether a state of charge of each of the cells is normal or abnormal based on the internal resistance of the cell calculated by the internal resistance calculating section; and

a second judging section for judging that a battery module including a cell determined to be abnormal by the first judging section is an abnormal battery module which requires replacement.

12. A module charger/discharger for adjusting a voltage of a replacement battery module which is used to replace an abnormal battery module of a battery set including a plurality of battery modules which each have a plurality of cells, wherein the replacement battery module is charged or discharged such that the voltage of the replacement battery module assumes an average voltage value calculated by a battery diagnostic apparatus comprising:

an internal resistance calculating section for calculating internal resistance of each of the cells;

a first judging section for judging whether a state of charge of each of the cells is normal or abnormal based on the internal resistance of the cell calculated by the internal resistance calculating section; and

a second judging section for judging that a battery module including a cell judged to be abnormal by the first judging section is an abnormal battery module which requires replacement.