Battery voltage monitoring device

• US 8,692,508 B2
• Filed: 04/08/2011
• Issued: 04/08/2014
• Est. Priority Date: 04/08/2010
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Shimizu, Takumi
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): PIGGUSH, AARON C
• Application Number:
  US13/082,499
• Publication Number:
  US 20110248677A1
• Time in Patent Office: 1,096 Days
• Field of Search: 320/118, 320/103, 320/119, 320/134, 320/136, 320/162
• US Class Current: 320/103
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery voltage monitoring device for efficiently equalizing cell voltages of a plurality of battery cells connected in series through a direct charge transfer between mutually distant battery cells. The device includes a charge-transfer circuit configured to perform a direct charge transfer from a first battery cell to a second battery cell that is fifth or higher adjacent to the first battery cell. This can eliminate charge-transfer losses that would occur during sequential charge transfers between adjacent battery cells, which leads to an efficient charge transfer between mutually distant battery cells.

Claims

1. A battery voltage monitoring device for equalizing cell voltages of a plurality of battery cells electrically connected in series, the plurality of battery cells being grouped into a plurality of blocks, the plurality of blocks being electrically connected in series and each having a same predetermined number of battery cells electrically connected in series, the device comprising:

cell-voltage detecting means for detecting cell voltages of the plurality of battery cells; and

charge-transferring means for performing a direct charge transfer from a first specific battery cell to a second specific battery cell that is second or higher adjacent to the first specific battery cell and has a lower cell voltage than the first specific battery cell on the basis of the cell voltages of the battery cells detected by the cell-voltage detecting means, the first specific battery cell belonging to a first block of the plurality of blocks and the second specific battery cell belonging to a second block of the plurality of blocks that is first or higher adjacent to the first block.

2. The device of claim 1, further comprising:

cell-voltage equalizing means for each of the plurality of blocks, the cell-voltage equalizing means being adapted to perform charge transfers between battery cells belonging to the block so as to equalize cell voltages of the battery cells of the block;

control means for operating the cell-voltage equalizing means and the charge-transferring means to equalize cell voltages of the plurality of battery cells on the basis of the cell voltages of the battery cells detected by the cell-voltage detecting means so that a total number of charge transfers is minimized.

3. The device of claim 1, wherein the charge-transferring means comprises switching means for switching between a charge-transfer-enabled mode and a charge-transfer-inhibited mode such that in the charge-transfer-enabled mode electric charge is allowed to be transferred from the first specific battery cell to the second specific battery cell, and in the charge-transfer-inhibited mode electric charge is not allowed to be transferred from the first specific battery cell to the second specific battery cell.

4. The device of claim 1, wherein the second specific battery cell is fifth or higher adjacent to the first specific battery cell.

5. A battery voltage monitoring device for equalizing cell voltages of a plurality of battery cells electrically connected in series, the plurality of battery cells being grouped into a plurality of blocks, the plurality of blocks being electrically connected in series and each having a same predetermined number of battery cells electrically connected in series, the device comprising:

a cell-voltage detection circuit adapted to detect cell voltages of the plurality of battery cells; and

a charge-transfer circuit adapted to perform a direct charge transfer from a first specific battery cell to a second specific battery cell that is second or higher adjacent to the first specific battery cell and has a lower cell voltage than the first battery cell on the basis of the cell voltages of the battery cells detected by the cell-voltage detection circuit, the first specific battery cell belonging to a first block of the plurality of blocks and the second specific battery cell belonging to a second block of the plurality of blocks that is first or higher adjacent to the first block.

6. The device of claim 5, further comprising:

a cell-voltage equalization circuit for each of the plurality of blocks, adapted to perform charge transfers between battery cells belonging to the block so as to equalize cell voltages of the battery cells of the block;

a control circuit adapted to operate the cell-voltage equalization circuit and the charge-transfer circuit to equalize cell voltages of the plurality of battery cells on the basis of the cell voltages of the battery cells detected by the cell-voltage detection circuit so that a total number of charge transfers is minimized.

7. The device of claim 5, wherein the charge-transfer circuit comprises one or more switches that are used to switch between a charge-transfer-enabled mode and a charge-transfer-inhibited mode of the charge-transfer circuit such that in the charge-transfer-enabled mode electric charge is allowed to be transferred from the first specific battery cell to the second specific battery cell by operatively turning on or off each of the switches, and in the charge-transfer-inhibited mode electric charge is not allowed to be transferred from the first specific battery cell to the second specific battery cell by keeping each of the switches turned off.

8. The device of claim 5, wherein the second specific battery cell is fifth or higher adjacent to the first specific battery cell.

9. The device of claim 5, wherein the charge-transfer circuit is of charge-pump type.

10. The device of claim 5, wherein the charge-transfer circuit is of flyback type.

11. The device of claim 5, wherein the charge-transfer circuit is of transformer type.