A multi-string lithium battery protection board detection protection circuit

Abstract

The utility model discloses a kind of multi-string lithium battery protection board detection protection circuit, it is related to lithium battery protection board technical field, including abnormality detection module, the signal of first protection board module, second protection board module or third protection board module sampling can be overvoltage or undervoltage detection, and when overvoltage or undervoltage occurs, whether the first protection board module, second protection board module or third protection board stops charging and discharging work is detected, and when not stopping charging and discharging work, first protection module and second protection module will be triggered to the first protection board module, second protection board module or third protection board module not stopping charging and discharging work is powered off protection and battery energy release protection processing.The utility model multi-string lithium battery protection board detection protection circuit improves the security of lithium battery protection board.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery protection board technology, specifically a detection and protection circuit for a multi-string lithium battery protection board. Background Technology

[0002] A lithium battery protection board (also known as a lithium battery protection board) is a protective integrated circuit board designed for rechargeable lithium batteries. It can realize the charging and discharging control of lithium batteries and perform power-off protection control when overvoltage or undervoltage occurs during the charging and discharging process. However, in the existing technology, the safety protection of lithium battery protection boards is relatively simple. If the charging and discharging control port of the lithium battery protection board is abnormal, it will not be able to perform power-off protection control normally, resulting in further damage to the lithium battery protection board and posing certain safety hazards. Therefore, it needs to be improved. Utility Model Content

[0003] This utility model embodiment provides a detection and protection circuit for a multi-string lithium battery protection board to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A detection and protection circuit for a multi-cell lithium battery protection board includes: a power module, a first protection module, a first protection board module, a second protection board module, a third protection board module, an anomaly detection module, and a second protection module.

[0006] The power module is used to connect to DC power.

[0007] The first protection module is connected to the power supply module, the anomaly detection module, the first protection board module, the second protection board module, and the third protection board module. It is used to transmit DC power to the first protection board module, the second protection board module, and the third protection board module. When it receives the first protection signal output by the anomaly detection module, it stops transmitting DC power to the first protection board module. When it receives the second protection signal output by the anomaly detection module, it stops transmitting DC power to the second protection board module. When it receives the third protection signal output by the anomaly detection module, it stops transmitting DC power to the third protection board module.

[0008] The first protection board module is used to receive DC power and perform charge and discharge control and charge and discharge voltage detection, and provides the first detection signal;

[0009] The second protection board module is used to receive DC power and perform charge and discharge control and charge and discharge voltage detection, and provides a second detection signal;

[0010] The third protection board module is used to receive DC power and perform charge and discharge control and charge and discharge voltage detection, and provides a third detection signal;

[0011] An anomaly detection module, connected to the first protection board module, the second protection board module, and the third protection board module, is used to perform overvoltage and undervoltage detection on the first detection signal, and output a first protection signal when overvoltage or undervoltage occurs and the first protection board module is in charge-discharge control; to perform overvoltage and undervoltage detection on the second detection signal, and output a second protection signal when overvoltage or undervoltage occurs and the second protection board module is in charge-discharge control; and to perform overvoltage and undervoltage detection on the third detection signal, and output a third protection signal when overvoltage or undervoltage occurs and the third protection board module is in charge-discharge control.

[0012] The second protection module, together with the anomaly detection module, the first protection board module, the second protection board module, and the third protection board module, is used to receive the first protection signal and perform pressure relief processing on the first protection board module, receive the second protection signal and perform pressure relief processing on the second protection board module, and receive the third protection signal and perform pressure relief processing on the third protection board module.

[0013] As a further embodiment of this utility model: the power module includes a power interface and a first capacitor; the first protection module includes a first resistor, a first power transistor and a first switching transistor; the first protection board module includes a first lithium battery protection board, a first diode and a second diode;

[0014] Preferably, the first end of the power interface is connected to the drain of the first power transistor and one end of the first capacitor, and is connected to the gate of the first power transistor and the collector of the first switching transistor through the first resistor. The source of the first power transistor is connected to the VCC terminal of the first lithium battery protection board. The other end of the first capacitor is connected to the collector of the first switching transistor, the GND terminal of the first lithium battery protection board, the second end of the power interface, and the ground terminal. The CS terminal of the first lithium battery protection board is connected to the abnormal detection module. The OD terminal and OC terminal of the first lithium battery protection board are respectively connected to the anode of the first diode and the anode of the second diode. The cathode of the first diode is connected to the cathode of the second diode.

[0015] As a further embodiment of this utility model: the first protection module further includes a second resistor, a second power transistor, and a second switching transistor; the second protection board module includes a second lithium battery protection board, a third diode, and a fourth diode;

[0016] Preferably, the drain of the second power transistor is connected to the first terminal of the power interface and is connected to the gate of the second power transistor and the collector of the second switching transistor through the second resistor. The emitter of the second switching transistor is connected to the GND terminal of the second lithium battery protection board. The source of the second power transistor is connected to the VCC terminal of the second lithium battery protection board. The OD terminal and OC terminal of the second lithium battery protection board are respectively connected to the anode of the third diode and the anode of the fourth diode. The cathode of the third diode is connected to the cathode of the fourth diode.

[0017] As a further embodiment of this utility model: the first protection module further includes a third resistor, a third power transistor, and a third switching transistor; the third protection board module includes a third lithium battery protection board, a fifth diode, and a sixth diode;

[0018] Preferably, the drain of the third power transistor is connected to the first terminal of the power interface and connected to the gate of the third power transistor and the collector of the third switching transistor through the third resistor. The emitter of the third switching transistor is connected to the GND terminal and the ground terminal of the third lithium battery protection board. The source of the third power transistor is connected to the VCC terminal of the third lithium battery protection board. The OD terminal and OC terminal of the third lithium battery protection board are respectively connected to the anode of the fifth diode and the anode of the sixth diode. The cathode of the fifth diode is connected to the cathode of the sixth diode.

[0019] As a further embodiment of this utility model: the second protection module includes a fourth power transistor, a fifth power transistor, a sixth power transistor, a fourth resistor, a fifth resistor, and a sixth resistor;

[0020] Preferably, the drains of the fourth, fifth, and sixth power transistors are connected to the VCC terminals of the third, second, and first lithium battery protection boards, respectively. The source of the fourth power transistor is grounded through a fourth resistor, the source of the fifth power transistor is grounded through a fifth resistor, and the source of the sixth power transistor is grounded through a sixth resistor. The gates of the fourth, fifth, and sixth power transistors are connected to the abnormality detection module.

[0021] As a further embodiment of this utility model: the anomaly detection module includes an overvoltage detection device, an undervoltage detection device, a first logic chip, a first detection device, and a second detection device;

[0022] Preferably, the input terminals of the overvoltage detection device and the undervoltage detection device are both connected to the CS terminal of the first lithium battery protection board. The A terminal of the first logic chip is connected to the output terminals of the overvoltage detection device and the undervoltage detection device. The B terminal of the first logic chip is connected to the cathode of the first diode. The Y terminal of the first logic chip is connected to the base of the first switching transistor and the gate of the fifth power transistor. The first and second input terminals of the first detection device are respectively connected to the CS terminal of the second lithium battery protection board and the cathode of the third diode. The first and second input terminals of the second detection device are respectively connected to the CS terminal of the third lithium battery protection board and the cathode of the fifth diode. The output terminal of the first detection device is connected to the gate of the sixth power transistor and the base of the second switching transistor. The output terminal of the second detection device is connected to the gate of the fourth power transistor and the base of the third switching transistor.

[0023] Compared with the prior art, the beneficial effects of this utility model are: the detection and protection circuit of the multi-string lithium battery protection board of this utility model can perform overvoltage or undervoltage detection on the signals sampled by the first protection board module, the second protection board module, or the third protection board module by the abnormal detection module. When overvoltage or undervoltage occurs, it detects whether the first protection board module, the second protection board module, or the third protection board has stopped charging and discharging. If it has not stopped charging and discharging, it will trigger the first protection module and the second protection module to perform power-off protection and battery energy leakage protection on the first protection board module, the second protection board module, or the third protection board module that has not stopped charging and discharging, thereby improving the safety of the lithium battery protection board. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic block diagram of the detection and protection circuit of a multi-string lithium battery protection board provided for this utility model embodiment.

[0026] Figure 2 A circuit diagram of a detection and protection circuit for a multi-string lithium battery protection board provided for this utility model embodiment.

[0027] Figure 3 The connection circuit diagram of the anomaly detection module provided for this utility model embodiment. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] In one embodiment, see Figure 1 A detection and protection circuit for a multi-string lithium battery protection board includes: a power module 1, a first protection module 2, a first protection board module 3, a second protection board module 4, a third protection board module 5, an anomaly detection module 6, and a second protection module 7.

[0030] Specifically, power module 1 is used to connect to DC power;

[0031] The first protection module 2 is connected to the power supply module 1, the anomaly detection module 6, the first protection board module 3, the second protection board module 4, and the third protection board module 5. It is used to transmit DC power to the first protection board module 3, the second protection board module 4, and the third protection board module 5. When it receives the first protection signal output by the anomaly detection module 6, it stops transmitting DC power to the first protection board module 3. When it receives the second protection signal output by the anomaly detection module 6, it stops transmitting DC power to the second protection board module 4. When it receives the third protection signal output by the anomaly detection module 6, it stops transmitting DC power to the third protection board module 5.

[0032] The first protection board module 3 is used to receive DC power and perform charge and discharge control and charge and discharge voltage detection, and provides a first detection signal;

[0033] The second protection board module 4 is used to receive DC power and perform charge and discharge control and charge and discharge voltage detection, and provides a second detection signal;

[0034] The third protection board module 5 is used to receive DC power and perform charge and discharge control and charge and discharge voltage detection, and provides a third detection signal;

[0035] An anomaly detection module 6, connected to the first protection board module 3, the second protection board module 4, and the third protection board module 5, is used to perform overvoltage and undervoltage detection on the first detection signal, and output a first protection signal when overvoltage or undervoltage occurs and the first protection board module 3 is in charge / discharge control; to perform overvoltage and undervoltage detection on the second detection signal, and output a second protection signal when overvoltage or undervoltage occurs and the second protection board module 4 is in charge / discharge control; and to perform overvoltage and undervoltage detection on the third detection signal, and output a third protection signal when overvoltage or undervoltage occurs and the third protection board module 5 is in charge / discharge control.

[0036] The second protection module 7, together with the anomaly detection module 6, the first protection board module 3, the second protection board module 4, and the third protection board module 5, is used to receive the first protection signal and perform pressure relief processing on the first protection board module 3, receive the second protection signal and perform pressure relief processing on the second protection board module 4, and receive the third protection signal and perform pressure relief processing on the third protection board module 5.

[0037] In a specific embodiment, the power module 1 can be a power circuit composed of a power interface and a capacitor, and can be connected to DC power; the first protection module 2 can be a first protection circuit composed of a field-effect transistor, a resistor, and a transistor, and can monitor the power transmission status and provide power-off protection; the first protection board module 3 can be a first protection board circuit composed of a lithium battery protection board and diodes, and can perform charge / discharge control, voltage sampling, and signal transmission; the second protection board module 4 can be a second protection board circuit composed of a lithium battery protection board and diodes, and can perform charge / discharge control, voltage sampling, and signal transmission; the third protection board module 5 can be a third protection board circuit composed of a lithium battery protection board and diodes. The protection board circuit can perform charging and discharging control, voltage sampling, and signal transmission. The above-mentioned abnormal detection module 6 can be composed of an overvoltage detection device, an undervoltage detection device, a first detection device, a second detection device, etc., and can perform overvoltage and undervoltage detection on the first protection board module 3, the second protection board module 4, or the third protection board module 5, and determine whether the first protection board module 3, the second protection board module 4, or the third protection board module 5 should stop charging and discharging when overvoltage or undervoltage occurs. The above-mentioned second protection module 7 can be composed of a field-effect transistor and a resistor, and can perform power discharge processing on the first protection board module 3, the second protection board module 4, or the third protection board module 5.

[0038] In another embodiment, please refer to Figure 1 , Figure 2 and Figure 3 The power module 1 includes a power interface and a first capacitor C1; the first protection module 2 includes a first resistor R1, a first power transistor Q1 and a first switching transistor V1; the first protection board module 3 includes a first lithium battery protection board IC1, a first diode D1 and a second diode D2.

[0039] Specifically, the first end of the power interface is connected to the drain of the first power transistor Q1 and one end of the first capacitor C1, and is connected to the gate of the first power transistor Q1 and the collector of the first switching transistor V1 through the first resistor R1. The source of the first power transistor Q1 is connected to the VCC terminal of the first lithium battery protection board IC1. The other end of the first capacitor C1 is connected to the collector of the first switching transistor V1, the GND terminal of the first lithium battery protection board IC1, the second end of the power interface, and the ground terminal. The CS terminal of the first lithium battery protection board IC1 is connected to the abnormal detection module 6. The OD terminal and OC terminal of the first lithium battery protection board IC1 are respectively connected to the anode of the first diode D1 and the anode of the second diode D2. The cathode of the first diode D1 is connected to the cathode of the second diode D2.

[0040] In a specific embodiment, the first power transistor Q1 can be an N-channel MOSFET; the first switching transistor V1 can be an NPN transistor; and the first lithium battery protection board IC1 can be a DW01 chip.

[0041] Furthermore, the first protection module 2 also includes a second resistor R2, a second power transistor Q2, and a second switch transistor V2; the second protection board module 4 includes a second lithium battery protection board IC2, a third diode D3, and a fourth diode D4;

[0042] Specifically, the drain of the second power transistor Q2 is connected to the first terminal of the power interface and is connected to the gate of the second power transistor Q2 and the collector of the second switching transistor V2 through the second resistor R2. The emitter of the second switching transistor V2 is connected to the GND terminal of the second lithium battery protection board IC2. The source of the second power transistor Q2 is connected to the VCC terminal of the second lithium battery protection board IC2. The OD terminal and OC terminal of the second lithium battery protection board IC2 are respectively connected to the anode of the third diode D3 and the anode of the fourth diode D4. The cathode of the third diode D3 is connected to the cathode of the fourth diode D4.

[0043] In a specific embodiment, the second power transistor Q2 can be an N-channel MOSFET; the second switching transistor V2 can be an NPN transistor; and the second lithium battery protection board IC2 can be a DW01 chip.

[0044] Furthermore, the first protection module 2 also includes a third resistor R3, a third power transistor Q3, and a third switch transistor V3; the third protection board module 5 includes a third lithium battery protection board IC3, a fifth diode D5, and a sixth diode D6;

[0045] Specifically, the drain of the third power transistor Q3 is connected to the first terminal of the power interface and is connected to the gate of the third power transistor Q3 and the collector of the third switching transistor V3 through the third resistor R3. The emitter of the third switching transistor V3 is connected to the GND terminal and the ground terminal of the third lithium battery protection board IC3. The source of the third power transistor Q3 is connected to the VCC terminal of the third lithium battery protection board IC3. The OD terminal and OC terminal of the third lithium battery protection board IC3 are respectively connected to the anode of the fifth diode D5 and the anode of the sixth diode D6. The cathode of the fifth diode D5 is connected to the cathode of the sixth diode D6.

[0046] In a specific embodiment, the third power transistor Q3 can be an N-channel MOSFET; the third switch transistor V3 can be an NPN transistor; and the third lithium battery protection board IC3 can be a DW01 chip.

[0047] Furthermore, the second protection module 7 includes a fourth power transistor Q4, a fifth power transistor Q5, a sixth power transistor Q6, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6;

[0048] Specifically, the drains of the fourth power transistor Q4, the fifth power transistor Q5, and the sixth power transistor Q6 are connected to the VCC terminals of the third lithium battery protection board IC3, the second lithium battery protection board IC2, and the first lithium battery protection board IC1, respectively. The source of the fourth power transistor Q4 is grounded through the fourth resistor R4, the source of the fifth power transistor Q5 is grounded through the fifth resistor R5, and the source of the sixth power transistor Q6 is grounded through the sixth resistor R6. The gates of the fourth power transistor Q4, the fifth power transistor Q5, and the sixth power transistor Q6 are connected to the abnormal detection module 6.

[0049] In a specific embodiment, the fourth power transistor Q4, the fifth power transistor Q5, and the sixth power transistor Q6 can all be N-channel field-effect transistors.

[0050] Furthermore, the anomaly detection module 6 includes an overvoltage detection device, an undervoltage detection device, a first logic chip J1, a first detection device, and a second detection device;

[0051] Specifically, the input terminals of the overvoltage detection device and the undervoltage detection device are both connected to the CS terminal of the first lithium battery protection board IC1. The A terminal of the first logic chip J1 is connected to the output terminals of the overvoltage detection device and the undervoltage detection device. The B terminal of the first logic chip J1 is connected to the cathode of the first diode D1. The Y terminal of the first logic chip J1 is connected to the base of the first switching transistor V1 and the gate of the fifth power transistor Q5. The first and second input terminals of the first detection device are respectively connected to the CS terminal of the second lithium battery protection board IC2 and the cathode of the third diode D3. The first and second input terminals of the second detection device are respectively connected to the CS terminal of the third lithium battery protection board IC3 and the cathode of the fifth diode D5. The output terminal of the first detection device is connected to the gate of the sixth power transistor Q6 and the base of the second switching transistor V2. The output terminal of the second detection device is connected to the gate of the fourth power transistor Q4 and the base of the third switching transistor V3.

[0052] In a specific embodiment, both the overvoltage detection device and the undervoltage detection device can be composed of a comparator, a resistor, and a reference power supply. The overvoltage detection device sets an overvoltage threshold through the reference power supply and compares the voltage with the first detection signal to perform overvoltage or undervoltage detection. The first logic chip J1 can be an AND gate chip. The circuit structure of the first detection device and the circuit structure of the second detection device are the same as the circuit structure of the overvoltage detection device, the undervoltage detection device, and the first logic chip J1.

[0053] In this embodiment, a detection and protection circuit for a multi-string lithium battery protection board is provided. DC power is supplied via a power interface. A first power transistor Q1 transmits power to a first lithium battery protection board IC1, a second power transistor Q2 transmits power to a second lithium battery protection board IC2, and a third power transistor Q3 transmits power to a third lithium battery protection board IC3. When the first lithium battery protection board IC1 is charging or discharging, a pulse signal is output from its OC or OD terminal and transmitted via a second diode D2 or a first diode D1. An overvoltage or undervoltage detection device samples the first detection signal from the CS terminal of the first lithium battery protection board IC1 for overvoltage or undervoltage detection. If overvoltage or undervoltage occurs, the OC or OD terminal of the first lithium battery protection board IC1 will stop outputting the pulse signal. However, the output of the pulse signal may not stop at the OC or OD terminal of the first lithium battery protection board IC1. When the signal is activated, the first logic chip J1 will output a high-level signal, i.e., the first protection signal, controlling the first switch V1 and the fifth power transistor Q5 to turn on, and the first power transistor Q1 to turn off, stopping the power supply to the VCC terminal of the first lithium battery protection board IC1 and pulling down the potential of the VCC terminal of the first lithium battery protection board IC1 to prevent the lithium battery connected to the VCC terminal of the first lithium battery protection board IC1 from releasing electrical energy and damaging the first lithium battery protection board IC1. Similarly, when the first detection device detects overvoltage or undervoltage in the second lithium battery protection board IC2, it will control the second switch V2 and the sixth power transistor Q6 to turn on, thereby disconnecting the power supply to the second lithium battery protection board IC2. When the second detection device detects overvoltage or undervoltage in the third lithium battery protection board IC3, it will control the third switch V3 and the fourth power transistor Q4 to turn on, thereby disconnecting the power supply to the third lithium battery protection board IC3.

[0054] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A detection and protection circuit for a multi-cell lithium battery protection board, characterized in that, The detection and protection circuit of the multi-string lithium battery protection board includes: a power module, a first protection module, a first protection board module, a second protection board module, a third protection board module, an anomaly detection module, and a second protection module. The power module is used to connect to DC power. The first protection module is connected to the power supply module, the anomaly detection module, the first protection board module, the second protection board module, and the third protection board module. It is used to transmit DC power to the first protection board module, the second protection board module, and the third protection board module. When it receives the first protection signal output by the anomaly detection module, it stops transmitting DC power to the first protection board module. When it receives the second protection signal output by the anomaly detection module, it stops transmitting DC power to the second protection board module. When it receives the third protection signal output by the anomaly detection module, it stops transmitting DC power to the third protection board module. The first protection board module is used to receive DC power and perform charge and discharge control and charge and discharge voltage detection, and provide a first detection signal; The second protection board module is used to receive DC power and perform charge / discharge control and charge / discharge voltage detection, and provide a second detection signal; The third protection board module is used to receive DC power and perform charge and discharge control and charge and discharge voltage detection, and provide a third detection signal; The anomaly detection module is connected to the first protection board module, the second protection board module, and the third protection board module. It is used to perform overvoltage and undervoltage detection on the first detection signal, and output a first protection signal when overvoltage or undervoltage occurs and the first protection board module is in charge-discharge control. It also performs overvoltage and undervoltage detection on the second detection signal, and outputs a second protection signal when overvoltage or undervoltage occurs and the second protection board module is in charge-discharge control. Finally, it performs overvoltage and undervoltage detection on the third detection signal, and outputs a third protection signal when overvoltage or undervoltage occurs and the third protection board module is in charge-discharge control. The second protection module, together with the anomaly detection module, the first protection board module, the second protection board module, and the third protection board module, is used to receive the first protection signal and perform pressure relief processing on the first protection board module, receive the second protection signal and perform pressure relief processing on the second protection board module, and receive the third protection signal and perform pressure relief processing on the third protection board module.

2. The detection and protection circuit for a multi-cell lithium battery protection board according to claim 1, characterized in that, The power module includes a power interface and a first capacitor; the first protection module includes a first resistor, a first power transistor, and a first switching transistor; the first protection board module includes a first lithium battery protection board, a first diode, and a second diode. The first end of the power interface is connected to the drain of the first power transistor and one end of the first capacitor, and is connected to the gate of the first power transistor and the collector of the first switching transistor through the first resistor. The source of the first power transistor is connected to the VCC terminal of the first lithium battery protection board. The other end of the first capacitor is connected to the collector of the first switching transistor, the GND terminal of the first lithium battery protection board, the second end of the power interface, and the ground terminal. The CS terminal of the first lithium battery protection board is connected to the abnormal detection module. The OD terminal and OC terminal of the first lithium battery protection board are respectively connected to the anode of the first diode and the anode of the second diode. The cathode of the first diode is connected to the cathode of the second diode.

3. The detection and protection circuit for a multi-cell lithium battery protection board according to claim 2, characterized in that, The first protection module further includes a second resistor, a second power transistor, and a second switching transistor; the second protection board module includes a second lithium battery protection board, a third diode, and a fourth diode; The drain of the second power transistor is connected to the first terminal of the power interface and is connected to the gate of the second power transistor and the collector of the second switching transistor through the second resistor. The emitter of the second switching transistor is connected to the GND terminal of the second lithium battery protection board. The source of the second power transistor is connected to the VCC terminal of the second lithium battery protection board. The OD terminal and OC terminal of the second lithium battery protection board are respectively connected to the anode of the third diode and the anode of the fourth diode. The cathode of the third diode is connected to the cathode of the fourth diode.

4. The detection and protection circuit for a multi-cell lithium battery protection board according to claim 3, characterized in that, The first protection module also includes a third resistor, a third power transistor, and a third switching transistor; the third protection board module includes a third lithium battery protection board, a fifth diode, and a sixth diode; The drain of the third power transistor is connected to the first end of the power interface and is connected to the gate of the third power transistor and the collector of the third switching transistor through the third resistor. The emitter of the third switching transistor is connected to the GND terminal and the ground terminal of the third lithium battery protection board. The source of the third power transistor is connected to the VCC terminal of the third lithium battery protection board. The OD terminal and OC terminal of the third lithium battery protection board are respectively connected to the anode of the fifth diode and the anode of the sixth diode. The cathode of the fifth diode is connected to the cathode of the sixth diode.

5. The detection and protection circuit for a multi-cell lithium battery protection board according to claim 4, characterized in that, The second protection module includes a fourth power transistor, a fifth power transistor, a sixth power transistor, a fourth resistor, a fifth resistor, and a sixth resistor; The drains of the fourth, fifth, and sixth power transistors are respectively connected to the VCC terminals of the third, second, and first lithium battery protection boards. The source of the fourth power transistor is grounded through a fourth resistor, the source of the fifth power transistor is grounded through a fifth resistor, and the source of the sixth power transistor is grounded through a sixth resistor. The gates of the fourth, fifth, and sixth power transistors are connected to the abnormality detection module.

6. The detection and protection circuit for a multi-cell lithium battery protection board according to claim 5, characterized in that, The anomaly detection module includes an overvoltage detection device, an undervoltage detection device, a first logic chip, a first detection device, and a second detection device; The input terminals of the overvoltage detection device and the undervoltage detection device are both connected to the CS terminal of the first lithium battery protection board. The A terminal of the first logic chip is connected to the output terminals of the overvoltage detection device and the undervoltage detection device. The B terminal of the first logic chip is connected to the cathode of the first diode. The Y terminal of the first logic chip is connected to the base of the first switching transistor and the gate of the fifth power transistor. The first and second input terminals of the first detection device are respectively connected to the CS terminal of the second lithium battery protection board and the cathode of the third diode. The first and second input terminals of the second detection device are respectively connected to the CS terminal of the third lithium battery protection board and the cathode of the fifth diode. The output terminal of the first detection device is connected to the gate of the sixth power transistor and the base of the second switching transistor. The output terminal of the second detection device is connected to the gate of the fourth power transistor and the base of the third switching transistor.

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