Voltage measuring circuit of battery pack

• US 20040041569A1
• Filed: 04/17/2003
• Published: 03/04/2004
• Est. Priority Date: 05/17/2001
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Furukawa, Kimihiko
• Granted Patent: US 6,919,706 B2
• Time in Patent Office: Days
• US Class Current: 324/433
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: G01R 15/04 Voltage dividers
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• 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: G01R 31/54 Testing for continuity
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• 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 voltage detecting circuit 2 for a cell combination comprising one or more cell blocks having a plurality of cell modules connected to each other in series, the circuit wherein voltage detecting lines 21 to 26 extend, respectively, from a plurality of voltage detecting points V1 to V6 of the cell combination 1, one of lines 23 is connected to the ground, and nongrounding voltage detecting lines are each interconnected through voltage branch lines 31 to 35 to the grounding voltage detecting line 23. A voltage dividing resistor is interposed on each of the nongrounding voltage detecting lines and each of the voltage branch lines. Each of the nongrounding voltage detecting line is connected to a computing circuit 5 via an analogue-digital converter 4. The computing circuit 5 calculates voltage of each of cell modules based on voltage detecting data input from each of the nongrounding voltage detecting lines. Accordingly, the number of parts is reduced, voltage detecting accuracy is improved, and disconnection is reliably detected.

Claims

1. In a cell combination comprising at least one cell block each having a plurality of cell modules connected to each other in series, a voltage detecting circuit for the cell combination which circuit detects voltage of each of the cell modules constituting the cell block, the circuit being characterized in that voltage detecting lines extend, respectively, from a plurality of voltage detecting points of the cell block, one of the voltage detecting lines is connected to the ground, nongrounding voltage detecting lines each is connected to the grounding voltage detecting line via a voltage branch line, a voltage dividing resistor is interposed on each of the nongrounding voltage detecting lines and on each of the voltage branch lines, each of the nongrounding voltage detecting lines is connected to computing means through analogue-digital conversion means, the computing means calculates voltage of each of the cell modules according to voltage detecting data to be input from each of the nongrounding voltage detecting lines.

2. A voltage detecting circuit according to claim 1 wherein the computing means comprises data correction means for correcting the voltage detecting data to be input through each of the nongrounding voltage detecting lines based on a preset correction method.

3. A voltage detecting circuit according to claim 1 or 2 wherein the computing means comprises disconnection detecting means for detecting the disconnection of each of the nongrounding voltage detecting lines based on the voltage detecting data to be input from each of the nongrounding voltage detecting lines.

4. A voltage detecting circuit according to any one of claims 1 to 3 wherein a disconnection checking circuit for checking the disconnection of the grounding voltage detecting line is interposed between the grounding voltage detecting line and the other voltage detecting line, and the disconnection checking circuit checks whether a closed loop circuit including the two voltage detecting lines and one or more cell modules is formed, to check the disconnection.

5. A voltage detecting circuit according to any one of claims 1 to 4 wherein a voltage detecting line extending from a voltage detecting point at the most central position among the plurality of voltage detecting points is connected to the ground as the grounding voltage detecting line.

6. A voltage detecting circuit according to claim 5 wherein a pair of voltage dividing resistors interposed on a nongrounding voltage detecting line extending from each end terminal of the cell block and on a voltage branch line interconnected to the nongrounding voltage detecting line is set at a smaller resistance value than a pair of voltage dividing resistors interposed on the other nongrouding voltage detecting line and on a voltage branch line interconnected to the nongrounding voltage detecting line.

7. A voltage detecting circuit according to any one of claims 1 to 6 wherein a capacitor is connected in parallel to a voltage dividing resistor interposed on each of the voltage branch lines.

8. A voltage detecting circuit according to claim 7 wherein a lowpass filter comprises the voltage dividing resistor and the capacitor which are connected to each other in parallel, and time constants of a plurality of lowpass filters formed by a plurality of the voltage branch lines are made uniform or approximately uniform.

9. A voltage detecting circuit according to claim 7 wherein a lowpass filter comprises the voltage dividing resistor and the capacitor which are connected to each other in parallel, and time constants of a plurality of lowpass filters formed by a plurality of the voltage branch lines is each set sufficiently longer than conversion processing time wherein the analogue-digital conversion means performs processing to all the detected voltage.