Multi-Cell Protection Circuit and Method

• US 20100207582A1
• Filed: 09/27/2008
• Published: 08/19/2010
• Est. Priority Date: 09/27/2007
• Status: Active Grant

• Current Assignee: BYD Semiconductor Co., Ltd.
• Original Assignee: BYD Company Limited
• Inventors: Yang, Qinyao, Wu, Zhengdong, Zhou, Jun
• Granted Patent: US 8,378,636 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A multi-cell protection circuit and method. The multi-cell protection circuit comprises one or more multi-cell protection chips, a charge control switch (M2) and a discharge control switch (M1). Each multi-cell protection chip comprises a multi-cell protection integrated circuit module and an expansion connection module. The input terminals (VC1, VC2, VC3, GND1, VC4, VC5, VC6, VC7, GND) of the multi-cell protection integrated circuit module are connected to the positive and negative poles of corresponding cells. The output terminals (co, do) of the multi-cell protection integrated circuit module are connected to the interior signal input terminals (Dco, Ddo) of the expansion connection module. The expansion signal input terminals (exterior.co, exterior.do) of the expansion connection module are connected to expansion signal output terminals (Co′, Do′) of an expansion connection module in a multi-cell protection chip adjacent to this multi-cell protection chip. The output terminals (Co′, Do′) of the expansion connection module in the last multi-cell protection chip among the multi-cell protection chips connected in the multi-cell protection circuit are connected to the charge control switch and the discharge control switch, respectively.

Claims

1. A multi-cell protection circuit, comprises one or more multi-cell protection chips, a charge control switch and a discharge control switch, wherein each multi-cell protection chip comprises a serially connected multi-cell battery protection integrated circuit module and an expansion connection module;

the input terminals of the serially connected multi-cell battery protection integrated circuit module are used to connect to the positive and negative poles of corresponding cells, and the output terminals are connected to the interior signal input terminals of the expansion connection module;

the expansion signal input terminals of the expansion connection module are connected to expansion signal output terminals of an expansion connection module in a multi-cell protection chip adjacent to this multi-cell protection chip, thereby the multi-cell protection chips connect together, and the expansion signal output terminals of the expansion connection module in the last connected multi-cell protection chip among the connected multi-cell protection chips are connected to the charge control switch and the discharge control switch, respectively.

2. The multi-cell protection circuit according to claim 1, wherein the expansion connection module comprises:

an expansion signal processing module, configured to convert the expansion output signals of the adjacent multi-cell protection chip to expansion input signals that can be identified by the multi-cell protection chip;

an expansion selection control signal processing module, configured to convert the expansion selection control signal of the multi-cell protection chip into an expansion selection control signal that can be identified by the multi-cell protection chip;

a logical processing module, configured to carry out logical operation for the interior input signals, the expansion input signals, and the expansion selection control signals; and

an output stage module, configured to output an expansion output signal according to the logical operation result of the logical processing module.

3. The multi-cell protection circuit according to claim 2, wherein the expansion signal processing module comprises:

an expansion charge signal processing module, configured to convert the expansion charge output signal of the adjacent multi-cell protection chip to an expansion charge input signal that can be identified by the multi-cell protection chip; and

an expansion discharge signal processing module, configured to convert the expansion discharge output signal of the adjacent multi-cell protection chip to an expansion discharge input signal that can be identified by the multi-cell protection chip.

4. The multi-cell protection circuit according to claim 2, wherein the multi-cell protection chips are connected through their expansion connection modules in upstream or downstream signal transmission direction;

in case of upstream signal transmission direction, the charge control switch and discharge control switch employ PMOSFETs and is connected with the uppermost multi-cell protection chip;

in case of downstream signal transmission direction, the charge control switch and discharge control switch employ NMOSFETs, and is connected with the bottommost multi-cell protection chip;

5. The multi-cell protection circuit according to claim 4, wherein if the multi-cell protection chips are connected through their expansion connection modules in upstream signal transmission direction:

the expansion signal processing module pulls up the high impedance state of the expansion output signal of the adjacent multi-cell protection chip to high level by means of a pull-up resistor and a level shifting device;

the logical processing module carries out logical operation for the interior input signals, the expansion output signals, and the expansion selection control signal with NAND gate or AND gate by selecting path with a path selector composed of transfer gates.

6. The multi-cell protection circuit according to claim 4, wherein if the multi-cell protection chips are connected through their expanded connection modules in downstream signal transmission direction:

the expansion signal processing module pulls down the high impedance state of the expansion output signal of the adjacent multi-cell protection chip to low level by means of a pull-down resistor and a level shifting device;

the logical processing module carries out logical operation for the interior input signals, the expansion output signals, and the expansion selection control signal with NAND gate or AND gate by selecting path with a path selector composed of transfer gates.

7. The multi-cell protection circuit according to claim 4, wherein if the multi-cell protection chips are connected through their expanded connection modules in upstream signal transmission direction:

the expansion signal processing module pulls up the high impedance state of the expansion output signal of the adjacent multi-cell protection chip to high level by means of a pull-up resistor and a level shifting device;

the logical processing module carries out logical operation for the interior input signals, the expansion output signals, and the expansion selection control signal with NOR gate or OR gate by selecting path with a path selector composed of MOSFETs.

8. The multi-cell protection circuit according to claim 4, wherein if the multi-cell protection chips are connected through their expanded connection modules in downstream signal transmission direction:

the expansion signal processing module pulls down the high impedance state of the expansion output signal of the adjacent multi-cell protection chip to low level by means of a pull-down resistor and a level shifting device;

the logical processing module carries out logical operation for the interior input signals, the expansion output signals, and the expansion selection control signal with NOR gate or OR gate by selecting path with a path selector composed of MOSFETs.

9. The multi-cell protection circuit according to claim 4, wherein if the multi-cell protection chips are connected through their expanded connection modules in upstream signal transmission direction:

the expansion selection control signal processing module comprises a first input terminal and a second input terminal;

the first input terminal of the bottommost multi-cell protection chip is connected to high level or in float state, and the first input terminals of the other multi-cell protection chips are connected to low level;

the second input terminal of the topmost multi-cell protection chip is connected to high level or in float state, and the second input terminals of the other multi-cell protection chips are connected to low level;

the expansion signal processing module pulls up the high impedance state of the expansion output signal of the adjacent multi-cell protection chip to high level by means of a pull-up resistor and a level shifting device;

the logical processing module carries out logical operation for the interior input signals, the expansion output signals, and the expansion selection control signal with NAND gate or AND gate.

10. The multi-cell protection circuit according to claim 4, wherein if the multi-cell protection chips are connected through their expanded connection modules in downstream signal transmission direction:

the expansion selection control signal processing module comprises a first input terminal and a second input terminal;

the first input terminal of the topmost multi-cell protection chip is connected to high level or in float state, and the first input terminals of the other multi-cell protection chips are connected to low level;

the second input terminal of the bottommost multi-cell protection chip is connected to high level or in float state, and the second input terminals of the other multi-cell protection chips are connected to low level;

the expansion signal processing module pulls down the high impedance state of the expansion output signal of the adjacent multi-cell protection chip to low level by means of a pull-down resistor and a level shifting device;

the logical processing module carries out logical operation for the interior input signals, the expansion output signals, and the expansion selection control signals with NAND gate or AND gate.

11. A method for protecting a multi-cell battery, comprises the following steps:

each multi-cell protection chip generating interior output signals that indicate the cell state, according to the state of the cell monitored by the protection chip;

each multi-cell protection chip carrying out logical decision one by one according to the interior input signals, an expansion selection control signal, and expansion output signals that indicate the expansion output state of a multi-cell protection chip adjacent to this multi-cell protection chip; and

controlling ON/OFF state of the cell charge/discharge circuit, according to the logical decision of the last multi-cell protection chip.