BMS circuit structure and lithium battery electric tool

Abstract

The invention provides a BMS circuit structure and a lithium battery electric tool, and belongs to the technical field of lithium batteries, the BMS circuit structure comprises an AFE chip, a connector, a first indicating lamp, a second indicating lamp, a first MOS tube, a second MOS tube, a first resistor and a second resistor; the AFE chip is electrically connected with the lithium battery through the connector; the first indicating lamp is connected in parallel with the source drain electrode of the first MOS tube, one end of the first indicating lamp is connected with the voltage pin of the AFE chip through the first resistor, and the other end of the first indicating lamp is grounded; one end of the second indicating lamp is connected with the voltage pin of the AFE chip through the second resistor, and the other end of the second indicating lamp is grounded through the source drain electrode of the second MOS tube; the grid electrode of the first MOS tube and the grid electrode of the second MOS tube are connected with the AFE chip. And the AFE chip is used for detecting the fault of the lithium battery and controlling the on-off of the first MOS tube and the second MOS tube. According to the invention, the problem that the lithium battery fault is difficult to display in the existing BMS circuit design scheme can be solved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically to a BMS circuit structure and a lithium battery power tool. Background Technology

[0002] With the continuous development of lithium-ion battery technology, lithium batteries are increasingly widely used in power tools, vacuum cleaners, and other fields. To ensure the safety and performance of lithium batteries, the Battery Management System (BMS) has become a crucial component. Currently, BMS designs for low-cell (4-cell and below) lithium battery power tools typically employ a single AFE chip circuit scheme to detect individual cell voltage, total voltage, current, and temperature, and to control the opening and closing of the power main circuit's charge / discharge switches. However, this design has significant shortcomings: when the AFE chip detects abnormal faults such as low or high individual cell voltage and temperature, it cannot directly transmit battery fault information to the user, making it difficult for operators to promptly identify power tool malfunctions. Existing BMS circuit designs lack product reliability and user experience. Summary of the Invention

[0003] In view of this, it is necessary to provide a BMS circuit structure and a lithium battery power tool to solve the technical problem that existing BMS circuit designs are unable to detect lithium battery faults.

[0004] To address the aforementioned problems, in a first aspect, the present invention provides a BMS circuit structure, comprising: an AFE chip, a connector, a first indicator light, a second indicator light, a first MOSFET, a second MOSFET, a first resistor, and a second resistor; The AFE chip is electrically connected to the lithium battery via the connector; The first indicator light is connected in parallel with the source and drain of the first MOSFET, and one end of the first indicator light is connected to the voltage pin of the AFE chip through the first resistor, while the other end of the first indicator light is grounded. One end of the second indicator light is connected to the voltage pin of the AFE chip through the second resistor, and the other end of the second indicator light is grounded through the source and drain of the second MOS transistor; Furthermore, the gates of both the first MOS transistor and the second MOS transistor are connected to the signal output terminal of the AFE chip; The AFE chip is used to detect faults in the lithium battery and control the switching on and off of the first MOSFET and the second MOSFET according to the fault type of the lithium battery.

[0005] In one possible implementation, the BMS circuit structure further includes: a charging drive module, a discharging drive module, a charging power module, and a discharging power module. One end of the charging power module is connected to the lithium battery, and the other end is connected to an external charging and discharging interface, used to adjust the charging power of the lithium battery and control the on / off state of the charging circuit. One end of the discharge power module is connected to the lithium battery, and the other end is connected to an external charging and discharging interface, used to adjust the discharge power of the lithium battery and control the on / off state of the discharge circuit. The charging drive module is used to control the operation of the charging power module; The discharge drive module is used to control the operation of the discharge power module.

[0006] In one possible implementation, the BMS circuit structure further includes: a self-locking switch; one end of the self-locking switch is connected to the charging drive module and the discharging drive module respectively, and the other end is grounded; The charging drive module is also used to control the charging power module to disconnect after the self-locking switch is closed; The discharge drive module is used to control the discharge power module to disconnect after the self-locking switch is closed.

[0007] In one possible implementation, the first indicator light is integrated into the self-locking switch.

[0008] In one possible implementation, the BMS circuit structure also includes: a third resistor, a fourth resistor, and a fifth resistor; The third resistor is connected in series between the lithium battery and the external charging / discharging interface; The fourth resistor is connected in series between the self-locking switch and the discharge drive module; The fifth resistor is connected in series between the self-locking switch and the charging drive model; The AFE chip is also used to acquire the charging and discharging current signal of the lithium battery through the third resistor, and to determine the fault of the lithium battery based on the charging and discharging current signal, as well as the temperature and voltage of the lithium battery cell.

[0009] In one possible implementation, the discharge power module includes a third MOSFET, a fourth MOSFET, and a fifth MOSFET whose source and drain are connected in parallel.

[0010] In one possible implementation, the charging power module includes a sixth MOSFET, a seventh MOSFET, and an eighth MOSFET whose source and drain are connected in parallel.

[0011] In one possible implementation, the BMS circuit structure further includes a sixth resistor; one end of the sixth resistor is connected to the signal output terminal of the AFE chip, and the other end is connected to the voltage pin of the AFE chip.

[0012] In one possible implementation, the first indicator light and the second indicator light are LEDs of different colors.

[0013] Secondly, the present invention also provides a lithium battery power tool, including the BMS circuit structure described in any of the above claims.

[0014] The beneficial effects of the above implementation are as follows: In the BMS circuit structure and lithium battery power tool provided by this invention, the voltage pin of the AFE chip continuously outputs a high-level voltage. At this time, the gate and source of the second MOSFET are at a high level, the second MOSFET is in a closed state, and the second indicator light is constantly on. The gate and source of the first MOSFET are at a high level, the first resistor is pulled down to ground, and the first indicator light has no current, thus it is off. Therefore, the operator can judge the working status of the lithium battery by the lighting status of the first and second indicator lights. When the AFE chip detects a fault in the lithium battery, it outputs a low-level voltage. The gate and source of the second MOSFET are at a low level, thus the second MOSFET is disconnected, and the second indicator light is off. Meanwhile, the gate and source of the first MOSFET are at a low level, and the first indicator light is constantly on. Therefore, this invention judges whether the lithium battery is working properly by the lighting status of the first and second indicator lights, solving the technical problem that existing BMS circuit designs cannot easily display lithium battery faults. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a circuit diagram of one embodiment of the BMS circuit structure provided by the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] In the description of the embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0019] In this embodiment of the invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product or device.

[0020] The naming or numbering of steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical order indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effect can be achieved.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] This invention provides a BMS (Battery Management System) circuit structure and a lithium battery power tool, which will be described below.

[0023] This invention provides a BMS circuit structure, including: an AFE (Active Front End) chip, a connector, a first indicator light, a second indicator light, a first MOSFET (Insulated Gate Field Effect Transistor), a second MOSFET, a first resistor, and a second resistor; as shown... Figure 1 As shown, the first indicator light is LED1, the second indicator light is LED2, the first MOSFET is MOS1, the second MOSFET is MOS2, the first resistor is R1, and the second resistor is R2.

[0024] The AFE chip is electrically connected to the lithium battery via the connector; The first indicator light is connected in parallel with the source and drain of the first MOSFET, and one end of the first indicator light is connected to the voltage pin of the AFE chip through the first resistor, while the other end of the first indicator light is grounded. One end of the second indicator light is connected to the voltage pin of the AFE chip through the second resistor, and the other end of the second indicator light is grounded through the source and drain of the second MOS transistor; Furthermore, the gates of both the first MOS transistor and the second MOS transistor are connected to the signal output terminal of the AFE chip; The AFE chip is used to detect faults in the lithium battery and control the switching on and off of the first MOSFET and the second MOSFET according to the fault type of the lithium battery.

[0025] Under normal operating conditions, the second indicator light of a lithium battery will remain on while the first indicator light will be off.

[0026] Specifically, the AFE chip's voltage pin continuously outputs a high-level voltage of 3.3V. At this time, the gate and source of the second MOSFET are at a high level, the second MOSFET is in a closed state, and the second indicator light is constantly on. Meanwhile, the gate and source of the first MOSFET are at a high level, the first resistor is pulled down to ground, and the first indicator light receives no current, thus remaining off. Therefore, operators can determine the lithium battery's operating status by observing the illumination status of the first and second indicator lights.

[0027] When the AFE chip detects a fault in the lithium battery, it outputs a low-level voltage. The gate and source of the second MOSFET are at a low level, so the second MOSFET is turned off and the second indicator light is off. Meanwhile, the gate and source of the first MOSFET are at a low level, so the first indicator light is always on.

[0028] Therefore, the present invention determines whether the lithium battery is working properly by observing the illumination status of the first indicator light and the second indicator light.

[0029] In some embodiments, the BMS circuit structure further includes: a charging drive module, a discharging drive module, a charging power module, and a discharging power module; One end of the charging power module is connected to the lithium battery, and the other end is connected to an external charging and discharging interface, used to adjust the charging power of the lithium battery and control the on / off state of the charging circuit. One end of the discharge power module is connected to the lithium battery, and the other end is connected to an external charging and discharging interface, used to adjust the discharge power of the lithium battery and control the on / off state of the discharge circuit. The charging drive module is used to control the operation of the charging power module; The discharge drive module is used to control the operation of the discharge power module.

[0030] It is understandable that the charging power module and the discharging power module can be composed of multiple MOSFETs. By controlling the on and off of multiple MOSFETs, the power control of lithium battery charging and discharging can be achieved.

[0031] The charging drive module can be controlled by outputting voltage signals to the gates of multiple MOSFETs in the charging power module. Similarly, the discharging drive module can be controlled by outputting voltage signals to the gates of multiple MOSFETs in the discharging power module. The charging power module and the discharging power module can be connected in series in the same circuit.

[0032] In some embodiments, the BMS circuit structure further includes: a self-locking switch, such as... Figure 1 As shown, the self-locking switch is K1; one end of the self-locking switch is connected to the charging drive module and the discharging drive module respectively, and the other end is grounded; The charging drive module is also used to control the charging power module to disconnect after the self-locking switch is closed; The discharge drive module is used to control the discharge power module to disconnect after the self-locking switch is closed.

[0033] The first indicator light is integrated into the self-locking switch.

[0034] Understandably, by combining the illumination status of the first and second indicator lights, users can identify whether there is a fault in the working status of the lithium battery. If a fault is found, users can disconnect the charging power module and the discharging power module through the self-locking switch to safely stop the power tool. This effectively prevents safety hazards such as overcharging and over-discharging of the battery caused by the fault, and further improves the safety of lithium battery power tools.

[0035] In some embodiments, the BMS circuit structure further includes: a third resistor, a fourth resistor, and a fifth resistor; such as Figure 1 As shown, the third resistor is R3, the fourth resistor is R4, and the fifth resistor is R5.

[0036] The third resistor is connected in series between the lithium battery and the external charging / discharging interface; The fourth resistor is connected in series between the self-locking switch and the discharge drive module; The fifth resistor is connected in series between the self-locking switch and the charging drive model; The AFE chip is also used to acquire the charging and discharging current signal of the lithium battery through the third resistor, and to determine the fault of the lithium battery based on the charging and discharging current signal, as well as the temperature and voltage of the lithium battery cell.

[0037] Understandably, the third resistor is a current sampling resistor, facilitating the AFE chip's acquisition of the lithium battery's charging and discharging current. The fourth and fifth resistors are pull-down resistors.

[0038] In some embodiments, the discharge power module includes: a third MOSFET, a fourth MOSFET, and a fifth MOSFET with their source and drain connected in parallel. The charging power module includes: a sixth MOSFET, a seventh MOSFET, and an eighth MOSFET with their source and drain connected in parallel. Figure 1As shown, the third MOSFET is MOS3, the fourth MOSFET is MOS4, the fifth MOSFET is MOS5, the sixth MOSFET is MOS6, the seventh MOSFET is MOS7, and the eighth MOSFET is MOS8.

[0039] It is understandable that the third, fourth, and fifth MOSFETs, as well as the sixth, seventh, and eighth MOSFETs, are all N-type MOSFETs.

[0040] In some embodiments, the BMS circuit structure further includes: a sixth resistor; one end of the sixth resistor is connected to the signal output terminal of the AFE chip, and the other end is connected to the voltage pin of the AFE chip.

[0041] Understandably, the sixth resistor is a pull-up resistor. The AFE chip uses the sixth resistor to pull up a 3.3V high-level output state to control the on / off state of the first and second MOSFETs.

[0042] In some embodiments, the first indicator light and the second indicator light are LEDs (light-emitting diodes) of different colors.

[0043] Understandably, the first indicator light can be red, and the second indicator light can be green.

[0044] In some embodiments, the BMS circuit structure proposed in this invention is a BMS circuit solution for battery status visualization and independent fault protection in portable power tools. It mainly consists of four series voltages (cells 1, 2, 3, and 4), an LDO (Low Dropout Linear Regulator) circuit module, a cell voltage and temperature acquisition circuit connector, a cell voltage acquisition and equalization circuit module, a cell temperature acquisition module, an AFE chip, a shunt current acquisition resistor (the third resistor), main circuit charging power NMOS 6, 7, and 8 (the sixth, seventh, and eighth MOSFETs); main circuit discharging power NMOS 3, 4, and 5 (the third, fourth, and fifth MOSFETs); a charging / discharging power MOSFET temperature detection module, a charging NMOS drive circuit module, a discharging NMOS drive circuit module, a charging NMOS drive circuit module pull-down resistor R5 (the fifth resistor), a discharging NMOS drive circuit module pull-down resistor R4 (the fourth resistor), a green status light display module with R2 (the second resistor), NMOS 2 (the second MOSFET), and LED 2 (the second indicator light), an internally integrated red LED (the first indicator light), and a self-locking button module with R1 (the first resistor), a self-locking switch K1, and NMOS 1 (the first MOSFET). The system consists of LED1 (the first indicator light), an external push-button switch, a motor load, and a charging device. The default state of both the self-locking switch K1 and the external push-button switch module is off. The portable power tool connects the actual external load motor or charging device to the BMS's power PACK+ / - main power circuit (i.e., the charging / discharging interface) via the external push-button switch for charging and discharging.

[0045] 1. BMS Normal Operation Mode Green LED2 (Second Indicator) Status Display Logic Explanation: By pre-configuring fixed strategies and instructions for the AFE chip, after the BMS is properly installed with the battery pack, the AFE is in normal operation mode. Its VOUT (+3.3V) pin (i.e., voltage pin) continuously outputs a high level of 3.3V. When the battery is detected to be fault-free, the AFE_FAULT (i.e., signal output terminal) is pulled up to a high level of 3.3V through resistor R6 (i.e., the sixth resistor). The AFE chip's CHG_DRIVE or DSG_DRIVE pin outputs a high level to drive the charging or discharging MOS drive circuit, further driving the charging process. When either the MOS (charging power module) or the discharge MOS (discharging power module) is in the closed state, the gate-source (GS) level of NMOS2 (the second MOS transistor) is at a high level, NMOS2 is in the closed state, and the green indicator light LED2 (the second indicator light) is constantly lit. At the same time, the gate-source (GS) level of NMOS1 (the first MOS transistor) is at a high level, and the resistor R1 (the first resistor) is pulled down to GND (ground). At this time, there is no current in the LED1 indicator light (the first indicator light), and the LED1 indicator light is in the off state. This means that the operator recognizes that the green indicator light is constantly lit to obtain that the BMS is working normally, and can then close the external button switch to use this portable power tool.

[0046] 2. Description of the red LED1 (first indicator light) status under BMS battery fault detection: When the AFE chip in the BMS system detects fault modes such as battery cell overvoltage or undervoltage, cell overtemperature, charge / discharge MOS overtemperature, battery charging overcurrent, or discharging overcurrent, the AFE chip, according to the fault protection threshold configured in its internal registers, drives the CHG_DRIVE or DSG_DRIVE output of the AFE chip to a low level. This drives the charging NMOS drive module (i.e., the charging drive module) or the discharging MOS drive circuit module (i.e., the discharging drive module) to output a low level, thereby driving the charging NMOS 6, 7, 8 (i.e., the sixth, seventh, and eighth MOS transistors) or the discharging NMOS 3, 4, 5 (i.e., the third, fourth, and fifth MOS transistors) to disconnect, thus cutting off the main power circuit for protection. At this time, the VOUT (+3.3V) pin (i.e., the voltage pin) of the AFE chip continuously outputs a high level of 3.3V, and the AFE_FAULT pin of the AFE chip, according to the fault protection threshold configured in its internal registers, drives the output of a low level according to the set fault protection strategy. At this time, the gate-source level of NMOS2 (i.e., the second MOS transistor) is low, NMOS2 is in the off state, and the green indicator light of LED2 (i.e., the second indicator light) is off; at this time, the gate-source level of NMOS1 (i.e., the first MOS transistor) is low, and the red indicator light of LED1 (i.e., the first indicator light) is always on.

[0047] 3. BMS Battery Fault Detection Mode Self-Locking Switch & External Button Switch Protection Strategy Description: When the BMS detects a battery fault, the red LED1 (i.e., the first indicator light) is constantly lit, and the green LED1 is off. The operator recognizes that the battery is in fault mode and manually presses the self-locking switch K1 to close it. At this time, the SWICH is pulled down to GND, that is, resistors R5 (i.e., the fifth resistor) and R4 (i.e., the fourth resistor) are pulled down to GND respectively, and CHG_MOS_CTL and DSG_MOS_CTL are both pulled down to GND. (By pulling CHG_MOS_CTL and DSG_MOS_CTL down to GND, it is further ensured that the charging NMOS drive module and the discharging NMOS drive module are in failure mode. The GS level drive level of charging NMOS6, 7, 8 or discharging NMOS3, 4, 5 can be forcibly pulled to GND to ensure that charging NMOS6, 7, 8 and discharging NMOS3, 4, 5 are in the open state.) Simultaneously, the operation identifies that the battery is in fault mode. By disconnecting the external switch button, ensure that the motor load or charging equipment and the BMS power main circuit are disconnected.

[0048] Compared with existing technologies, the BMS circuit solution for battery status visualization and independent fault protection in portable power tools provided by this invention has the following advantages: 1. By adopting a circuit design scheme with a single AFE chip, when the AFE chip detects abnormal faults in the voltage and temperature of a single lithium battery cell, it can promptly control the on / off state of the red and green indicator lights by switching the high and low levels of the ALERT pin of the AFE chip. This enables rapid judgment of the power tool's status, effectively solving the problem of the inability to promptly identify power tool faults in existing technologies, and significantly improving the safety and reliability of power tools.

[0049] 2. By integrating the red fault indicator light into the self-locking switch, and combining the on / off changes of the red indicator light, users can promptly identify when the red indicator light is on and press the self-locking button to directly force the disconnection of the charging NMOS and discharging NMOS of the BMS, thus achieving safe shutdown of the power tool. This effectively prevents safety hazards such as battery overcharging and over-discharging caused by faults, further improving the safety of lithium battery power tools.

[0050] 3. By combining the on / off state of green and red indicator lights, compared to the single indicator light design in existing technologies, the working status of the power tool can be more intuitively indicated to the user, improving the user experience and providing better visual perception, thus enhancing the human-computer interaction of the product.

[0051] 4. By placing red and green indicator lights in different locations on the power tool, along with a self-locking switch, users can more easily determine the status and handle faults during operation, effectively simplifying the operation process and improving the user experience.

[0052] 5. The circuit design of this invention is simple in structure and easy to implement, requiring only a small amount of hardware resources. It has good practicality and economy, and can be widely used in various low-series 4-cell batteries and some lithium battery power tools, such as lawnmowers, hair dryers and vacuum cleaners. It has strong versatility and practical value.

[0053] The present invention also provides a lithium battery power tool, which includes the BMS circuit structure described in any of the above claims.

[0054] Understandably, lithium battery power tools can be electric vehicles, as well as lawnmowers, hair dryers, and vacuum cleaners.

[0055] The BMS circuit structure and lithium battery electric tools provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A BMS circuit structure, characterized in that, include: AFE chip, connector, first indicator light, second indicator light, first MOSFET, second MOSFET, first resistor and second resistor; The AFE chip is electrically connected to the lithium battery via the connector; The first indicator light is connected in parallel with the source and drain of the first MOSFET, and one end of the first indicator light is connected to the voltage pin of the AFE chip through the first resistor, while the other end of the first indicator light is grounded. One end of the second indicator light is connected to the voltage pin of the AFE chip through the second resistor, and the other end of the second indicator light is grounded through the source and drain of the second MOS transistor; Furthermore, the gates of both the first MOS transistor and the second MOS transistor are connected to the signal output terminal of the AFE chip; The AFE chip is used to detect faults in the lithium battery and control the switching on and off of the first MOSFET and the second MOSFET according to the fault type of the lithium battery.

2. The BMS circuit structure according to claim 1, characterized in that, Also includes: Charging drive module, discharging drive module, charging power module, and discharging power module; One end of the charging power module is connected to the lithium battery, and the other end is connected to an external charging and discharging interface, used to adjust the charging power of the lithium battery and control the on / off state of the charging circuit. One end of the discharge power module is connected to the lithium battery, and the other end is connected to an external charging and discharging interface, used to adjust the discharge power of the lithium battery and control the on / off state of the discharge circuit. The charging drive module is used to control the operation of the charging power module; The discharge drive module is used to control the operation of the discharge power module.

3. The BMS circuit structure according to claim 2, characterized in that, Also includes: A self-locking switch; one end of the self-locking switch is connected to both the charging drive module and the discharging drive module, and the other end is grounded; The charging drive module is also used to control the charging power module to disconnect after the self-locking switch is closed; The discharge drive module is used to control the discharge power module to disconnect after the self-locking switch is closed.

4. The BMS circuit structure according to claim 3, characterized in that, The first indicator light is integrated into the self-locking switch.

5. The BMS circuit structure according to claim 2, characterized in that, Also includes: The third resistor, the fourth resistor, and the fifth resistor; The third resistor is connected in series between the lithium battery and the external charging / discharging interface; The fourth resistor is connected in series between the self-locking switch and the discharge drive module; The fifth resistor is connected in series between the self-locking switch and the charging drive model; The AFE chip is also used to acquire the charging and discharging current signal of the lithium battery through the third resistor, and to determine the fault of the lithium battery based on the charging and discharging current signal, as well as the temperature and voltage of the lithium battery cell.

6. The BMS circuit structure according to claim 2, characterized in that, The discharge power module includes a third MOSFET, a fourth MOSFET, and a fifth MOSFET whose source and drain are connected in parallel.

7. The BMS circuit structure according to claim 2, characterized in that, The charging power module includes a sixth MOSFET, a seventh MOSFET, and an eighth MOSFET whose source and drain are connected in parallel.

8. The BMS circuit structure according to claim 1, characterized in that, Also includes: The sixth resistor; one end of the sixth resistor is connected to the signal output terminal of the AFE chip, and the other end is connected to the voltage pin of the AFE chip.

9. The BMS circuit structure according to any one of claims 1-8, characterized in that, The first indicator light and the second indicator light are LEDs of different colors.

10. A lithium battery-powered power tool, characterized in that, Includes the BMS circuit structure as described in any one of claims 1-9.

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