BATTERY MONITORING APPARATUS

• US 20160061909A1
• Filed: 09/01/2015
• Published: 03/03/2016
• Est. Priority Date: 09/01/2014
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: MIZOGUCHI, Tomomichi, MIURA, Ryotaro, IINO, Junichi
• Granted Patent: US 9,933,489 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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: G01R 31/66 Testing of connections, e.g. of plugs or non-disconnectable joints testing for incorrect line connections G01R31/55

Abstract

A battery monitoring apparatus includes wire sections each connected to a node of corresponding adjacent two of the unit cells of a battery pack at one end thereof, and branched into a first branch section and a second branch section at another end thereof. Each of the first and second branch sections is constituted of a positive part connected to a positive electrode of the corresponding unit cell and a negative part connected to a negative electrode of the corresponding unit cell. The battery monitoring apparatus includes an equalizing switch provided between each of the first wire pairs, and a voltage detector to detect a voltage between each first wire pair, and an equalizing section which performs an equalizing process to equalize a terminal voltage of each unit cell by turning on the corresponding equalizing switch depending on a result of voltage detection by the voltage detector.

Claims

1. A battery monitoring apparatus for a battery pack including a plurality of unit cells connected in series, comprising:

a plurality of wire sections each of which is connected to a node between a corresponding adjacent two of the unit cells at one end thereof, and branched into a first branch section and a second branch section at another end thereof, each of the first and second branch sections being constituted of a positive part connected to a positive electrode of a corresponding one of the unit cells and a negative part connected to a negative electrode of the corresponding one of the unit cells,

for each of the wire sections, the positive part of the second branch section and the negative part of the first branch section constitute a first wire pair, and the positive part of the first branch section and the negative part of the second branch section constitute a second wire pair;

an equalizing switch provided between each of the first wire pairs to short-circuit the first wire pair when being turned on;

a first voltage detector provided in parallel to each of the equalizing switches to detect a voltage between a corresponding one of the first wire pair;

an equalizing section which performs an equalizing process to equalize a terminal voltage of each unit cell by turning on a corresponding one of the equalizing switches depending on a result of voltage detection by the first voltage detector; and

a second voltage detector provided between each of the second wire pairs for detecting the terminal voltage of a corresponding one of the unit cells when the equalizing switch is on and when the equalizing switch is off.

2. The battery monitoring apparatus according to claim 1, further comprising a deterioration detecting section which determines whether or not each of the wire sections has been deteriorated based on a result of voltage detection performed by the second voltage detector when the equalizing switch is on and a result of voltage detection performed by the second voltage detector when the equalizing switch is off.

3. The battery monitoring apparatus according to claim 2, wherein the deterioration detecting section calculates a resistance of each of the wire sections based on a difference between a first voltage detection value detected by the second voltage detector when the equalizing switch is on and a second voltage detection value detected by the second voltage detector when the equalizing switch is off.

4. The battery monitoring apparatus according to claim 3, further comprising an abnormality determining section which determines for each of the wire sections that there is an abnormality in the wire section if the resistance calculated by the deterioration detecting section exceeds a first threshold value.

5. The battery monitoring apparatus according to claim 4, further comprising a correcting section which corrects the voltage detected by the first voltage detector if the resistance calculated by the deterioration detecting section is larger than the first threshold value and smaller than a second threshold value which is larger than the first threshold value.

6. The battery monitoring apparatus according to claim 5, wherein the equalizing section performs the equalizing process in accordance with the voltage corrected by the correcting section.

7. The battery monitoring apparatus according to claim 3, further comprising a resistance-increase identifying section which identifies, for each of the wire sections, which of the positive part and the negative part has increased in resistance based on the resistance values of two adjacent wire sections.

8. The battery monitoring apparatus according to claim 3, further comprising a notifying section which makes notification that the resistance value detected by the deterioration detecting section exceeds a predetermined value.

9. The battery monitoring apparatus according to claim 1, further comprising an RC filter provided in each of the first wire pairs.