Assembled Battery Total Voltage Detection Circuit

• US 20090243621A1
• Filed: 02/19/2009
• Published: 10/01/2009
• Est. Priority Date: 03/27/2008
• Status: Active Grant

• Current Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd., Hitachi Vehicle Energy, Ltd. (Hitachi, Ltd.)
• Inventors: KIKUCHI, Mutsumi, NAGAOKA, Masaki, KUDO, Akihiko
• Granted Patent: US 8,760,168 B2
• Time in Patent Office: Days
• US Class Current: 324/426
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0038 relating to sensors
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: G01R 19/0084 measuring voltage only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An assembled battery total voltage detection circuit includes a main control circuit, a divider resistor connected between a plus terminal and a minus terminal of an assembled battery insulated from the main control circuit, and a differential amplifier circuit that amplifies voltage divided by the divider resistor. A constant electric potential relative to a ground of the main control circuit is applied to a midpoint of the divider resistor. The main control circuit measures the voltage divided by the divider resistor via the differential amplifier circuit.

Claims

1. An assembled battery total voltage detection circuit, comprising:

a main control circuit;

a divider resistor connected between a plus terminal and a minus terminal of an assembled battery insulated from the main control circuit; and

a differential amplifier circuit that amplifies voltage divided by the divider resistor, wherein;

a constant electric potential relative to a ground of the main control circuit is applied to a midpoint of the divider resistor; and

the main control circuit measures the voltage divided by the divider resistor via the differential amplifier circuit.

2. An assembled battery total voltage detection circuit according to claim 1, wherein

the differential amplifier circuit includes a buffer and a differential amplifier.

3. An assembled battery total voltage detection circuit according to claim 2, wherein

the buffer and the differential amplifier are each constituted by an operational amplifier that operates with a single power supply.

4. An assembled battery total voltage detection circuit according to claim 1, further comprising

a buffer constituted by an operational amplifier that operates with a single power supply, wherein

a positive constant electric potential is applied to the midpoint of the divider resistor with using the buffer.

5. An assembled battery total voltage detection circuit according to claim 3, wherein

a plurality of the operational amplifiers are packed into a single package.

6. An assembled battery total voltage detection circuit according to claim 1, further comprising

a resister of which a resistance value is smaller than that of the divider resistor, the resister being connected in parallel to the divider resistor.

7. An assembled battery total voltage detection circuit according to claim 6, further comprising

two switching elements, one of which is inserted between the plus terminal of the assembled battery and the divider resistor, the other of which is inserted between the minus terminal of the assembled battery and the divider resistor, wherein,

at a time of measuring a total voltage of the assembled battery, the main control circuit controls the switching elements to be ON and measures the voltage divided by the divider resistor via the differential amplifier circuit.

8. An assembled battery total voltage detection circuit according to claim 1, wherein

the main control circuit includes a first failure detection unit that performs failure detection for the differential amplifier circuit.

9. An assembled battery total voltage detection circuit according to claim 4, wherein

the main control circuit includes a second failure detection unit that performs failure detection for the buffer.

10. An assembled battery total voltage detection circuit, comprising:

a main control circuit;

a divider resistor connected between a plus terminal and a minus terminal of an assembled battery insulated from the main control circuit, the divider resister being constituted by a series circuit consisting of first, second, third and fourth resistors; and

a differential amplifier circuit including a positive phase input terminal which is connected to a connection point of the first and second resistors, and a negative phase input terminal which is connected to a connection point of the third and fourth resistors, wherein;

a constant electric potential relative to a ground of the main control circuit is applied to a connection point of the second and third resistors; and

the main control circuit measures output voltage of the differential amplifier circuit.

11. An assembled battery total voltage detection circuit according to claim 10, wherein

the differential amplifier circuit includes a buffer and a differential amplifier.

12. An assembled battery total voltage detection circuit according to claim 11, wherein:

the differential amplifier circuit includes a first buffer and a second buffer;

the connection point of the first and second resistors is connected to an input terminal of the first buffer;

the connection point of the third and fourth resistors is connected to an input terminal of the second buffer; and

output terminals of the first and second buffers are connected to the positive phase input terminal and the negative phase input terminal of the differential amplifier, respectively.

13. An assembled battery total voltage detection circuit according to claim 12, wherein

the first and second buffers and the differential amplifier are each constituted by an operational amplifier that operates with a single power supply.

14. An assembled battery total voltage detection circuit according to claim 10, further comprising

a buffer constituted by an operational amplifier that operates with a single power supply, wherein

a positive constant electric potential is applied to the connection point of the second and third resistors with using the buffer.

15. An assembled battery total voltage detection circuit according to claim 13, wherein

a plurality of the operational amplifiers are packed into a single package.

16. An assembled battery total voltage detection circuit according to claim 10, further comprising:

a first and a second switching elements, the first switching element being inserted between the plus terminal of the assembled battery and the first resistor, the second switching element being inserted between the minus terminal of the assembled battery and the fourth resistor; and

a resister of which a resistance value is smaller than that of a sum of the first, second, third and fourth resistors, the resister being connected in parallel between a connection point at which the first switching element and the first resistor are connected, and a connection point at which the second switching element and the fourth resistor are connected, wherein,

at a time of measuring a total voltage of the assembled battery, the main control circuit controls the first and second switching elements to be ON and measures voltage between the connection point of the first and second resistors and the connection point of the third and fourth resistors via the differential amplifier circuit.

17. An assembled battery total voltage detection circuit, comprising:

a main control circuit;

a divider resistor connected between a plus terminal and a minus terminal of an assembled battery insulated from the main control circuit, the divider resistor being constituted by a series circuit consisting of first, second, third and fourth resistors;

a differential amplifier circuit including a positive phase input terminal which is connected to a connection point of the first and second resistors, and a negative phase input terminal which is connected to a connection point of the third and fourth resistors, and

a buffer constituted by an operational amplifier that operates with a single power supply, wherein;

a constant electric potential relative to a ground of the main control circuit is applied to a connection point of the second and third resistors with using the buffer; and

the main control circuit measures output voltage of the differential amplifier circuit so as to measure a total voltage of the assembled battery, and includes a first failure detection unit that performs failure detection for the differential amplifier circuit.

18. An assembled battery total voltage detection circuit according to claim 17, wherein

the first failure detection unit detects input voltage values to a positive phase input side and a negative phase input side of the differential amplifier circuit and an output voltage value from an output side of the differential amplifier circuit, and, if a value obtained by “

(the output voltage value of the differential amplifier circuit)/{(the input voltage value to the positive phase input side)−

(the input voltage value to the negative phase input side)}”

is outside a range of a predetermined amplification factor of the differential amplifier circuit, judges the differential amplifier circuit to be at fault.

19. An assembled battery total voltage detection circuit according to claim 17, wherein

the main control circuit further includes a second failure detection unit that performs failure detection for the buffer.

20. An assembled battery total voltage detection circuit according to claim 19, wherein

the second failure detection unit detects an output voltage value of the buffer, and, if the detected output voltage value is outside a predetermined range, judges the buffer to be at fault.