SECONDARY BATTERY, INSPECTION APPARATUS AND INSPECTION METHOD FOR SECONDARY BATTERY, AND BATTERY INSPECTION SYSTEM

• US 20130069662A1
• Filed: 06/04/2010
• Published: 03/21/2013
• Est. Priority Date: 06/04/2010
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Tanabe, Yukinari
• Granted Patent: US 9,182,448 B2
• Time in Patent Office: Days
• US Class Current: 324/434
• 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: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• 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 plurality of detection units are connected respectively in parallel with a plurality of battery cells connected in series. The detection units each include an inductor and a zener diode connected in series. A battery checker includes a plurality of detection inductors and a single voltmeter that form a closed circuit. A plurality of detection inductors are arranged so that they are magnetically coupled respectively with the inductors of the plurality of detection units. Each zener diode is connected with the polarity to be reverse biased by the output voltage of the battery cell. Respective breakdown voltages of the zener diodes are set higher than the output voltage of each battery cell in normal use and different in a stepwise manner from each other.

Claims

1. A secondary battery comprising:

a plurality of battery cells connected in series; and

a plurality of detection units connected in parallel with said plurality of battery cells respectively,

said plurality of detection units each including a reactor and a zener diode connected in series,

each said zener diode having a breakdown voltage higher than an output voltage of a corresponding one of said battery cells in use, and

respective breakdown voltages of respective said zener diodes of said plurality of detection units being designed to have respective values different in a stepwise manner from each other.

2. The secondary battery according to claim 1, wherein

said plurality of battery cells include first to n-th battery cells connected successively, n being an integer of two or more,

said plurality of detection units include first to n-th detection units connected in parallel with said first to n-th battery cells respectively, and

said zener diode in an i-th detection unit has a breakdown voltage lower than the breakdown voltage of said zener diode in an (i+1)-th detection unit, i being an integer of one to (n−

1).

3. The secondary battery according to claim 1, wherein

when said secondary battery is inspected, said secondary battery is supplied with a charging voltage higher than a charging voltage supplied to said secondary battery in use.

4. The secondary battery according to claim 3, wherein

said secondary battery is mounted on a hybrid vehicle,

said hybrid vehicle is mounted with a power generation mechanism for generating charging power for said secondary battery, and a control unit controlling said power generation mechanism, and

when said secondary battery is inspected, said control unit controls said power generation mechanism so that said secondary battery is supplied with constant current (It) larger than an upper limit of charging current for said secondary battery when said hybrid vehicle is being operated.

5. An inspection apparatus for a secondary battery,

said secondary battery including:

a plurality of battery cells connected in series; and

a plurality of detection units connected in parallel with said plurality of battery cells respectively, and

said plurality of detection units each including a reactor and a zener diode connected in series, said zener diode having a breakdown voltage higher than an output voltage of a corresponding one of said battery cells in use,

said inspection apparatus comprising;

a plurality of detection reactors connected in series; and

a voltage detector connected in series with said plurality of detection reactors to constitute a closed circuit, and

said plurality of detection reactors each being arranged so that, when said inspection apparatus is attached to said secondary battery for inspecting said secondary battery, each said detection reactor is magnetically coupled with said reactor in a corresponding one of said plurality of detection units in which respective breakdown voltages of respective said zener diodes are designed to have respective values different in a stepwise manner from each other.

6. The inspection apparatus for a secondary battery according to claim 5, wherein

when said secondary battery is inspected, said secondary battery is supplied with a charging voltage higher than a charging voltage supplied to said secondary battery in use.

7. The inspection apparatus for a secondary battery according to claim 6, wherein

said secondary battery is mounted on a hybrid vehicle,

said hybrid vehicle is mounted with a power generation mechanism for generating charging power for said secondary battery, and a control unit controlling said power generation mechanism, and

when said secondary battery is inspected, said control unit controls said power generation mechanism so that said secondary battery is supplied with constant current larger than an upper limit of charging current for said secondary battery when said hybrid vehicle is being operated.

8. A battery inspection system comprising:

a secondary battery; and

an inspection apparatus for said secondary battery,

said secondary battery including;

a plurality of battery cells connected in series; and

a plurality of detection units connected in parallel with said plurality of battery cells respectively,

said plurality of detection units each including a reactor and a zener diode connected in series,

each said zener diode having a breakdown voltage higher than an output voltage of a corresponding one of said battery cells in use, and

respective breakdown voltages of respective said zener diodes of said plurality of detection units being designed to have respective values different in a stepwise manner from each other,

said inspection apparatus including;

a plurality of detection reactors connected in series; and

a voltage detector connected in series with said plurality of detection reactors to constitute a closed circuit, and

said plurality of detection reactors each being arranged so that, when said inspection apparatus is attached to said secondary battery for inspecting said secondary battery, each said detection reactor is magnetically coupled with said reactor in a corresponding one of said plurality of detection units.

9. The battery inspection system according to claim 8, wherein

when said secondary battery is inspected, said secondary battery is supplied with a charging voltage higher than a charging voltage supplied to said secondary battery in use.

10. The battery inspection system according to claim 8, wherein

said secondary battery is housed in a first casing on which a recessed portion is formed,

said inspection apparatus is housed in a second casing on which a protruded portion shaped to fit in said recessed portion is formed, and

each said reactor and each said detection reactor are arranged respectively at said recessed portion and said protruded portion so that, when said protruded portion is fit in said recessed portion, said plurality of detection reactors are each magnetically coupled with said reactor in a corresponding one of said plurality of detection units.

11. The battery inspection system according to claim 9, wherein

said secondary battery is mounted on a hybrid vehicle,

said hybrid vehicle is mounted with a power generation mechanism for generating charging power for said secondary battery, and a control unit controlling said power generation mechanism, and when said secondary battery is inspected, said control unit controls said power generation mechanism so that said secondary battery is supplied with constant current (It) larger than an upper limit of charging current for said secondary battery when said hybrid vehicle is being operated.

12. An inspection method for a secondary battery including a plurality of battery cells connected in series, comprising the steps of:

attaching an inspection apparatus to said secondary battery, said inspection apparatus having a closed circuit constituted of a plurality of detection reactors and a voltage detector connected in series, and said secondary battery having a plurality of detection units connected in parallel with said plurality of battery cells respectively,

said plurality of detection units each including a reactor and a zener diode connected in series,

each said zener diode having a breakdown voltage higher than an output voltage of a corresponding one of said battery cells in use, and respective breakdown voltages of respective said zener diodes of said plurality of detection units being designed to have respective values different in a stepwise manner from each other, and

said plurality of detection reactors each being arranged so that, when said inspection apparatus is attached to said secondary battery, each said detection reactor is magnetically coupled with said reactor in a corresponding one of said plurality of detection units;

supplying a charging voltage higher than a charging voltage supplied to said secondary battery in use, to said secondary battery to which said inspection apparatus is attached;

measuring a parameter for determining, for each of said plurality of battery cells, whether said battery cell is degraded, based on a voltage waveform at said voltage detector after a test current is applied to said secondary battery;

determining whether an abnormal cell having an increased internal resistance is present among said plurality of battery cells, based on said measured parameter; and

identifying said abnormal cell among said plurality of battery cells based on said parameter, when it is determined that said abnormal cell is present.

13. The inspection method for a secondary battery according to claim 12, wherein

said parameter includes the number of steps in which voltage changes in a stepwise manner in said voltage waveform, and

said step of determining includes the step of determining whether said abnormal cell is present, based on said number of steps.

14. The inspection method for a secondary battery according to claim 12, wherein

said parameter includes a time width of each voltage step in which voltage changes in a stepwise manner in said voltage waveform, and

said step of identifying includes the step of identifying said abnormal cell among said plurality of battery cells, based on said time width.

15. The inspection method for a secondary battery according to claim 12, further comprising the steps of:

measuring said parameter by said inspection apparatus at the start of use of said secondary battery or when said secondary battery is new; and

storing said measured parameter as reference data, wherein

said step of determining includes the step of determining whether said abnormal cell is present, based on a comparison between said reference data and said parameter measured when inspection is conducted, and

said step of identifying includes the step of identifying said abnormal cell among said plurality of battery cells, based on a comparison between said reference data and said parameter measured when inspection is conducted.

16. The inspection method for a secondary battery according to claim 12, wherein

said secondary battery is mounted on a hybrid vehicle,

said hybrid vehicle is mounted with a power generation mechanism for generating charging power for said secondary battery, and

said step of supplying includes the step of controlling said power generation mechanism so that said secondary battery is supplied with constant current larger than an upper limit of charging current for said secondary battery when said hybrid vehicle is being operated.

17. The inspection method for a secondary battery according to claim 12, wherein

said secondary battery is housed in a first casing on which a recessed portion is formed,

said inspection apparatus is housed in a second casing on which a protruded portion shaped to fit in said recessed portion is formed,

each said reactor and each said detection reactor are arranged respectively at said recessed portion and said protruded portion, and

in said step of attaching, said protruded portion is fit in said recessed portion to allow said plurality of detection reactors each to be positioned so that said detection reactor is magnetically coupled with said reactor in a corresponding one of said plurality of detection units.