Lithium battery protection circuit

Abstract

The utility model discloses a lithium battery protection circuit, the lithium battery is by N electric core series connection and is composed, and the positive pole B+ of lithium battery, B- is connected charging by positive pole charging terminal C+ and negative pole discharge end P- respectively, and the positive pole charging line has the charging MOS pipe group in series connection, and the negative pole charging line has the discharge MOS pipe group in series connection, the lithium battery protection circuit includes protection chip U1, and protection chip U1 gathers the voltage of each electric core of lithium battery, and the on-off of control charging MOS pipe group, discharge MOS pipe group is connected, and then control the charge -discharge of lithium battery, the utility model discloses the design of the parallel configuration of multiple MOS pipe, the current channel of charge -discharge circuit is increased significantly, and the current load is effectively shared. In combination on the negative pole charging line in series connection a plurality of parallel resistance, make the circuit can steady support 45A even higher sustained discharge current, perfect satisfied the demand of high -power application scene such as electric tool, large -capacity energy storage equipment.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery protection, and in particular to a lithium battery protection circuit. Background Technology

[0002] With the rapid development of portable electronic devices, power tools, energy storage systems, and other fields, lithium battery packs have been widely used due to their advantages such as high energy density and long cycle life. Lithium battery packs composed of multiple cells connected in series can provide higher voltage to meet the power demands of high-power devices.

[0003] However, under abnormal operating conditions such as overcharging, over-discharging, and overcurrent, the performance and lifespan of lithium battery packs will drop sharply, and may even lead to serious safety accidents such as thermal runaway, fire, and explosion. Therefore, reliable protection circuits are crucial for the safe use of lithium battery packs. Traditional lithium battery protection circuits typically use dedicated protection chips to monitor battery voltage and current, and achieve protection functions by controlling the switching of MOSFETs (metal-oxide-semiconductor field-effect transistors) connected in series in the charging and discharging circuit.

[0004] However, traditional protection circuit designs face challenges in high-power applications requiring support for large currents (e.g., 45A or higher) during charging and discharging. A single MOSFET often cannot withstand such a large continuous current, leading to excessive on-resistance, severe heat generation, and consequently affecting system efficiency and reliability. While multiple MOSFETs can be connected in parallel to shunt the current, simple parallel connections introduce current sharing issues, and achieving stable and efficient control in conjunction with the protection chip is a technical problem that needs to be solved. Furthermore, under high-current conditions, the circuit demands even greater speed and protection capabilities against overload and short-circuit faults. Utility Model Content

[0005] The purpose of this invention is to provide a lithium battery protection circuit that can support high current operation and has high reliability and high safety. The technical solution of this utility model is: A lithium battery protection circuit is provided, wherein the lithium battery consists of N cells connected in series. The positive and negative terminals B+ and B- of the lithium battery are connected to the positive charging terminal C+ and the negative discharging terminal P- for charging, respectively. A charging MOSFET group is connected in series on the positive charging line, and a discharging MOSFET group is connected in series on the negative charging line. The lithium battery protection circuit includes a protection chip U1. The protection chip U1 collects the voltage of each cell of the lithium battery and controls the on / off state of the charging MOSFET group and the discharging MOSFET group, thereby controlling the charging and discharging of the lithium battery.

[0006] Preferably, the protection chip U1 is a battery protection IC CW1074ALBS.

[0007] Preferably, the charging MOSFET group includes MOSFETs Q2, Q4, Q10, and Q11, wherein MOSFETs Q2 and Q4 are connected in parallel, MOSFETs Q10 and Q11 are connected in parallel, and the two sets of parallel MOSFETs are connected in series. The charging control pin CO of the protection chip U1 is connected to control the gates of the two sets of parallel MOSFETs through transistors Q1 and Q9 respectively.

[0008] Preferably, the discharge MOS transistor group includes MOS transistors Q5-Q8 connected in parallel, and the discharge control pin DO of the protection chip U1 is connected to the gate of the control MOS transistors Q5-Q8 respectively.

[0009] Preferably, the negative charging line is also connected in series with several parallel resistors to support a continuous discharge current of 45A or more.

[0010] Preferably, the positive charging line is also connected in series with several fuses connected in parallel.

[0011] The advantages of this utility model are: This invention employs a parallel configuration of multiple MOSFETs (e.g., parallel connection of discharge MOSFETs Q5-Q8, and parallel connection of charging MOSFETs Q2, Q4, Q10, and Q11), significantly increasing the current path of the charging and discharging circuit and effectively distributing the current load. Combined with several parallel resistors connected in series on the negative charging line, the circuit can stably support a continuous discharge current of 45A or even higher, perfectly meeting the needs of high-power applications such as power tools and large-capacity energy storage devices. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the lithium battery protection circuit of this utility model. Detailed Implementation

[0013] like Figure 1 As shown, a lithium battery protection circuit is described. The lithium battery consists of four cells connected in series. The positive and negative terminals B+ and B- of the lithium battery are connected to the positive charging terminal C+ and the negative discharging terminal P- for charging, respectively. A charging MOSFET group is connected in series on the positive charging line, and a discharging MOSFET group is connected in series on the negative charging line. The lithium battery protection circuit includes a protection chip U1 (battery protection ICCW1074ALBS). The protection chip U1 collects the voltages B1-B4 of each cell of the lithium battery and connects to control the on / off state of the charging MOSFET group and the discharging MOSFET group, thereby controlling the charging and discharging of the lithium battery.

[0014] The charging MOSFET group includes MOSFETs Q2, Q4, Q10, and Q11. MOSFETs Q2 and Q4 are connected in parallel, and MOSFETs Q10 and Q11 are connected in parallel. The two sets of parallel MOSFETs are then connected in series. The charging control pin CO of the protection chip U1 is connected to control the gates of the two sets of parallel MOSFETs through transistors Q1 and Q9, respectively.

[0015] The discharge MOS transistor group includes MOS transistors Q5-Q8 connected in parallel, and the discharge control pin DO of the protection chip U1 is connected to the gate of the control MOS transistors Q5-Q8 respectively.

[0016] This invention employs a parallel configuration of multiple MOSFETs (e.g., parallel connection of discharge MOSFETs Q5-Q8, and parallel connection of charging MOSFETs Q2, Q4, Q10, and Q11), significantly increasing the current path of the charging and discharging circuit and effectively distributing the current load. Combined with four parallel resistors R31-R34 connected in series on the negative charging line, the circuit can stably support a continuous discharge current of 45A or even higher, perfectly meeting the needs of high-power applications such as power tools and large-capacity energy storage devices.

[0017] The positive charging line is also connected in series with four parallel fuses F1-F4.

[0018] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All modifications made in accordance with the spirit and essence of the main technical solution of this utility model should be included within the scope of protection of this utility model.

Claims

1. A lithium battery protection circuit, characterized in that, The lithium battery consists of N cells connected in series. The positive and negative terminals B+ and B- of the lithium battery are connected to the positive charging terminal C+ and the negative discharging terminal P- for charging, respectively. A charging MOSFET group is connected in series on the positive charging line, and a discharging MOSFET group is connected in series on the negative charging line. The lithium battery protection circuit includes a protection chip U1. The protection chip U1 collects the voltage of each cell of the lithium battery and connects to control the on / off state of the charging MOSFET group and the discharging MOSFET group, thereby controlling the charging and discharging of the lithium battery.

2. The lithium battery protection circuit according to claim 1, characterized in that, The protection chip U1 uses the battery protection IC CW1074ALBS.

3. The lithium battery protection circuit according to claim 2, characterized in that, The charging MOSFET group includes MOSFETs Q2, Q4, Q10, and Q11. MOSFETs Q2 and Q4 are connected in parallel, and MOSFETs Q10 and Q11 are connected in parallel. The two sets of parallel MOSFETs are then connected in series. The charging control pin CO of the protection chip U1 is connected to control the gates of the two sets of parallel MOSFETs through transistors Q1 and Q9, respectively.

4. The lithium battery protection circuit according to claim 2, characterized in that, The discharge MOS transistor group includes MOS transistors Q5-Q8 connected in parallel, and the discharge control pin DO of the protection chip U1 is connected to the gate of the control MOS transistors Q5-Q8 respectively.

5. The lithium battery protection circuit according to claim 4, characterized in that, The negative charging line is also connected in series with several parallel resistors to support a continuous discharge current of 45A or more.

6. The lithium battery protection circuit according to claim 5, characterized in that, Several fuses connected in parallel are also connected in series on the positive charging line.

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