Battery protection plate external short circuit active protection method and battery protection plate

Abstract

The present application belongs to the field of battery protection, and particularly relates to a kind of battery protection plate outside short circuit active protection method and battery protection plate, when battery is in first activation state, the state of external connection is detected by pre-charging circuit, if external is open circuit state, then actively disconnect discharge switch, until the normal condition of external connection is detected again close discharge switch, to avoid the risk of external short circuit caused by external not normal connection. When battery is in running state, whether need to trigger active protection is judged by the size of discharge current, during active protection, periodically control and disconnect the active protection circuit connected between the junction of discharge switch and pre-charging circuit and P-point, according to the voltage output signal of the junction of discharge switch and pre-charging circuit;According to the duty cycle in output signal, the state of external connection is judged, and each switch is controlled according to the state of external connection. Thus, the present application solves the problem of protection plate internal fuse burnout and repair caused by external wiring harness short circuit.

Description

Technical Field

[0001] This invention belongs to the field of battery protection technology, specifically relating to an active protection method for external short circuits of a battery protection board and a battery protection board. Background Technology

[0002] In the prior art, a 24V / 48V protection board includes: a charging and discharging circuit and a pre-charging circuit. One end of the charging and discharging circuit is used to connect to the battery, and the other end is used to connect to the load. A discharging MOSFET and a charging MOSFET are connected in series on the charging and discharging circuit. The pre-charging circuit is connected in parallel with the discharging MOSFET. A pre-charging MOSFET and a pre-charging group R are connected in series on the pre-charging circuit. The board also includes an MCU, which is used to control the switching of the discharging MOSFET, the charging MOSFET, and the pre-charging MOSFET.

[0003] Although most of the 24V / 48V protection boards used in backup power supplies have pre-charging circuits and pre-charging functions, they do not have the function of actively preventing external short circuits. Since most protection boards are always in an active state, during assembly and maintenance, there are often problems such as external wiring harness short circuits causing the internal fuse of the protection board PACK to blow and require repair. Summary of the Invention

[0004] The purpose of this invention is to provide an active protection method for external short circuits of a battery protection board and a battery protection board, so as to solve the problem that external wiring harness short circuits often cause the internal fuses of the protection board PACK to burn out and require repair.

[0005] To solve the above-mentioned technical problems, the technical solution provided by this invention and the corresponding beneficial effects of the technical solution are as follows:

[0006] The present invention provides an active protection method for external short circuit of a battery protection board, the method comprising active protection when the battery is in the initial activation state and when the battery is in the running state;

[0007] When the battery is in its first activation state, the following detection logic is executed:

[0008] 1) Control the pre-charge switch to alternately close and open according to the first duty cycle within the cycle;

[0009] 2) Detect the pre-charge current and the voltage at point P+; point P+ is the positive connection point for connecting an external load; point P- is the negative connection point for connecting an external load; the external load is equivalent to a capacitor, denoted as the equivalent capacitor;

[0010] 3) Determine the magnitudes of the pre-charging current and the voltage at point P+, respectively;

[0011] 4) If the pre-charge current is greater than the set battery current value and the voltage at point P+ is less than the set minimum voltage value, then disconnect the battery discharge switch; the set battery current value is obtained based on the ratio of the battery voltage to the pre-charge resistance.

[0012] When the battery is in operation, the following operation status detection logic is executed:

[0013] 1) If the discharge current is less than the current value corresponding to the external static power consumption and has been maintained for a set time, then disconnect the discharge switch, close the pre-charge switch and the charging switch;

[0014] 2) Control the active protection switch to alternately close and open according to the second duty cycle within the cycle; the active protection switch is connected in parallel between the parallel connection point of the discharge switch and the pre-charge circuit and the P- point, and is connected in parallel with the equivalent capacitor;

[0015] 3) Collect the parallel connection voltage of the discharge switch and the pre-charge circuit, compare the parallel connection voltage with the reference voltage, and output an output signal containing duty cycle information;

[0016] 4) If the duty cycle in the output signal is within the second duty cycle range, the discharge switch remains open, the charging switch remains closed, the active protection switch remains open, and the initial activation state detection logic is entered; if the duty cycle in the output signal is not within the second duty cycle range, the discharge switch and the charging switch are closed.

[0017] The beneficial effects of the above technical solution are as follows: In the activation state detection logic, this invention only controls the periodic opening and closing of the pre-charge switch, and then determines the external short circuit situation based on the magnitude of the pre-charge current and the voltage at P+. In the event of a short circuit, the discharge switch is not closed. Furthermore, because the pre-charge resistor limits the current and periodically closes and opens the pre-charge switch in the pre-charge circuit, it can prevent the pre-charge resistor from overheating and causing other risks. Therefore, this invention has no risk, achieves active protection, and solves the problem of the internal fuse of the protection board PACK burning out and requiring repair due to an external wiring harness short circuit. On the other hand, this invention does not increase the cost of the original product, and at the same time reduces the risk of external short circuits to achieve the purpose of cost reduction and efficiency improvement.

[0018] When the battery is in operation, this invention connects an active protection switch in parallel between the connection point of the discharge switch and the pre-charge circuit and the P-point, and in parallel with an equivalent capacitor. By controlling the active protection switch to periodically close and open, and then determining whether to perform active protection based on the discharge current magnitude, active protection is initiated. During active protection, the discharge switch is opened, the pre-charge switch and the charging switch are closed, and the opening and closing of the active protection switch is periodically controlled. Based on the voltage at the connection point of the discharge switch and the pre-charge circuit, a signal containing duty cycle information is output. This duty cycle is used to determine the external load connection status, thereby controlling each switch. This invention, based on the original design, does not modify the original hardware and electrical architecture, only expanding the original pre-charge function to implement an active protection strategy against external short circuits. It is simple to process, has a fast detection speed and high reliability, requires fewer detection devices, and has low cost.

[0019] Furthermore, in order to facilitate normal use of the battery, when the battery is in operation, in step 1), if the discharge current is greater than the current value corresponding to the external static power consumption, the discharge switch is closed. The current value corresponding to the external static power consumption is determined according to the external load.

[0020] Furthermore, to facilitate normal battery use, when the battery is in operation, if the pre-charge current is greater than the set pre-charge current ratio after the discharge switch is turned off and the pre-charge switch and charging switch are turned on, the discharge switch will immediately close, and the pre-charge switch and active protection switch will be turned off. The set pre-charge current ratio is determined based on the ratio of battery voltage to pre-charge resistance.

[0021] Furthermore, to improve reliability, when the battery is in the initial activation state, in step 4), if the pre-charge current is less than the set zero current approximation and the voltage at P+ is greater than the battery voltage approximation, then the battery discharge switch is disconnected; the battery voltage approximation is determined based on the battery voltage.

[0022] Furthermore, to improve reliability, when the battery is in the initial activation state, in step 4), if there is a pre-charge current and the voltage at P+ shows an upward trend until the voltage at P+ is greater than the approximate value of the battery voltage, then the pre-charge switch is disconnected and the discharge switch and charging switch are closed.

[0023] Furthermore, if the duty cycle in the output signal is within the second duty cycle range, the discharge switch remains open, the charging switch remains closed, and the active protection switch remains open, while the pre-charging current and the voltage at point P+ are continuously monitored; if the duty cycle in the output signal is not within the first duty cycle range, the discharge current is continuously monitored after the discharge switch and the charging switch are closed.

[0024] Furthermore, to improve reliability, when the battery is in the initial activation state, the pre-charge current and the voltage at point P+ need to be determined n times. If all n determinations are satisfied, the condition is considered satisfied, and the corresponding switch action is controlled, where n≥3.

[0025] Furthermore, the range of the second duty cycle is [b-5%, b+5%], where b is the set value of the second duty cycle.

[0026] This invention discloses a battery protection board, comprising a charging / discharging circuit and a pre-charging circuit. One end of the charging / discharging circuit is connected to a battery, and the other end is connected to a load. A discharging switch and a charging switch are connected in series on the charging / discharging circuit. The pre-charging circuit is connected in parallel with the discharging switch. A pre-charging switch is connected in series on the pre-charging circuit. The board also includes a microprocessor for controlling the switching of the discharging switch, the charging switch, and the pre-charging switch. The battery protection board further includes an active protection circuit and a comparator. The active protection circuit is connected in parallel between the parallel connection point of the discharging switch and the pre-charging circuit and point P-, and in parallel with an equivalent capacitor. Point P- is the negative terminal connection point for connecting an external load. The equivalent capacitor is obtained by equating the external load. An active protection switch and a protection resistor are connected in series on the active protection circuit. The input terminal of the comparator is connected to the parallel connection point of the discharging switch and the pre-charging circuit, and is used to compare the voltage at the parallel connection point of the discharging switch and the pre-charging circuit with a reference voltage, and output an output signal containing duty cycle information to the microcontroller.

[0027] Microprocessors are also used for:

[0028] Active protection when the battery is in the initial activation state and / or when the battery is in operation;

[0029] When the battery is in an active state, the following detection logic is executed:

[0030] 1) Control the pre-charge switch to alternately close and open according to the first duty cycle within the cycle;

[0031] 2) Obtain the pre-charge current and the voltage at point P+; point P+ is the positive connection point used to connect to an external load;

[0032] 3) Determine the magnitudes of the pre-charging current and the voltage at point P+, respectively;

[0033] 4) If the pre-charge current is greater than the set battery current value and the voltage at point P+ is less than the set minimum voltage value, then disconnect the battery discharge switch; the set battery current value is obtained based on the ratio of the battery voltage to the pre-charge resistance.

[0034] When the battery is in operation, the following operation status detection logic is executed:

[0035] 1) If the discharge current is less than the current value corresponding to the external static power consumption and has been maintained for a set time, then disconnect the discharge switch, close the pre-charge switch and the charging switch;

[0036] 2) Control the active protection switch to alternately close and open according to the second duty cycle within the cycle; the active protection switch is connected in parallel between the parallel connection point of the discharge switch and the pre-charge circuit and the P- point, and is connected in parallel with the equivalent capacitor;

[0037] 3) Obtain the output signal containing duty cycle information;

[0038] 4) If the duty cycle in the output signal is within the second duty cycle range, the discharge switch remains open, the charging switch remains closed, the active protection switch remains open, and the initial activation state detection logic is entered; if the duty cycle in the output signal is not within the second duty cycle range, the discharge switch and the charging switch are closed. Attached Figure Description

[0039] Figure 1 This is a circuit diagram of a 24V / 48V protection board with active protection function in an embodiment of the battery protection board of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0041] Battery protection board example:

[0042] An embodiment of the battery protection board of the present invention, such as Figure 1 The diagram shown is an electrical diagram of an active protection battery protection board according to the present invention. BPC is a schematic diagram of the internal workings of the battery protection board. This embodiment uses... Figure 1 Taking the battery protection board as an example, in this embodiment, the discharge switch is the discharge MOSFET Q2, the charging switch is the charging MOSFET Q3, the pre-charging switch is the pre-charging MOSFET Q4, the active protection switch is the active protection MOSFET Q1, and the equivalent capacitor is capacitor C.

[0043] The battery protection board includes a charging / discharging circuit, a pre-charging circuit, an active protection circuit, a microprocessor, and a comparator. One end of the charging / discharging circuit is connected to the battery, and the other end is connected to the load. A discharge MOSFET Q2 and a charging MOSFET Q3 are connected in series in the charging / discharging circuit. The pre-charging circuit is connected in parallel with the discharge MOSFET Q2. A discharge MOSFET Q2 and a pre-charging resistor R1 are connected in series in the pre-charging circuit. The active protection circuit is connected in parallel between the parallel connection point of the discharge switch and the pre-charging circuit and point P-, and is also connected in parallel with an equivalent capacitor. Point P+ is the positive connection point for connecting the external load, and point P- is the negative connection point for connecting the external load. The external load is equivalent to a capacitor, denoted as the equivalent capacitor, also called capacitor C. An active protection MOSFET Q1 and a protection resistor R2 are connected in series in the active protection circuit. The input of the comparator cmp is connected to the parallel connection point of the discharge switch and the pre-charging circuit, used to compare the voltage at the parallel connection point of the discharge switch and the pre-charging circuit with a reference voltage, and outputs an output signal containing duty cycle information to the microcontroller. The microprocessor is used to control the switching of the discharge switch, active protection switch, charging switch, and pre-charge switch. It should be noted that... Figure 1 In the diagram, B+ and B- are the positive and negative terminals of the battery, respectively; P+ and P- are the two terminals of the protection board that connect to the external load. When P+ and P- are connected to the external load, capacitor C exists; when P+ and P- are not connected to the external load, capacitor C does not exist.

[0044] The specific working process of the battery protection board of this invention for actively protecting against external short circuits is as follows:

[0045] This invention primarily provides active protection against external short circuits in the following scenarios; in this embodiment, it focuses on... Figure 1 The circuit in the diagram will be explained.

[0046] Initial state: Battery is initially powered on and activated. The monitoring process in the initial state is as follows:

[0047] S1: External status monitoring function is activated, the charging MOSFET is closed, and then the pre-charge MOSFET is periodically closed and opened by the MCU.

[0048] The pre-charge circuit is as follows: B+ → charging MOSFET → pre-charge MOSFET → R → P+ → P- → B-. Whether this pre-charge circuit is conductive depends on whether P+ and P- have external connections. In this embodiment, a square wave with a period t of 2s and a duty cycle of 50% (first duty cycle) is used to achieve the periodic opening and closing of the pre-charge MOSFET. The period t is determined based on the maximum value of capacitor C, battery voltage, pre-charge time, power of pre-charge resistor R, and pre-charge frequency, and is set within the safe range for ensuring the pre-charge MOSFET. The duty cycle can also be other set ratios.

[0049] S2: Monitor the pre-charge current and the voltage at P+ to determine the external state.

[0050] If no pre-charge current is detected, i.e., the pre-charge current is less than the set approximate zero current value, and the voltage at P+ is close to the battery voltage, the pre-charge circuit is in an open state, indicating that no external connection is made. To improve detection accuracy and reliability, this embodiment requires monitoring 5 times. If all 5 monitoring tests meet the conditions of no pre-charge current and the voltage at P+ being close to the battery voltage, it indicates that there is indeed no external connection, meaning no external charging or discharging equipment is connected, and the protection board disconnects the discharge MOS. The range of the number of monitoring tests is [3, 15], depending on the specific requirements.

[0051] If a large pre-charge current is detected, close to the ratio of battery voltage to pre-charge resistor, and the voltage at P+ is close to 0V, it indicates an external short circuit has occurred, and the device is in an external short circuit condition. Because this invention limits the current of the pre-charge resistor and periodically closes and opens the pre-charge MOSFET, it prevents excessive power from the pre-charge resistor R, thus preventing the pre-charge resistor from burning out. Therefore, there is no risk, achieving active protection and solving the problem of the protection board PACK's internal fuse burning out and requiring repair due to an external wiring harness short circuit.

[0052] If a pre-charge current is detected and the HV2 voltage (also the voltage at P+) shows an upward trend, eventually approaching the battery voltage (i.e., the HV2 voltage is greater than the approximate battery voltage), it indicates that the external connection is normal and the discharge MOS can be closed for external use.

[0053] Normal battery operation status: The pre-charge MOS is disconnected, and the charge / discharge MOS is closed, entering the normal operation status.

[0054] This state is primarily used to detect external short circuits during disassembly and maintenance. Once the battery enters normal operating condition, the battery current is detected, and the corresponding detection procedure is executed based on the magnitude of the battery current, as follows:

[0055] 1) If the detected discharge current is greater than the current value corresponding to the external static power consumption, it indicates that the external connection is normal and there will be no short circuit between P+ and P- on the protection board. In this case, the monitoring mechanism will not be triggered, and the discharge MOSFET will close. The external static power consumption is the power consumption of the connected external load when it is not operating. In this embodiment, the external static power consumption value is 0.5A.

[0056] 2) If the detected discharge current is less than the external static power consumption and remains so for 1 minute, then the discharge MOSFET is disconnected, the pre-charge MOSFET is closed, and the external short-circuit active monitoring process begins. This indicates that there is no external connection and no power is required, but disassembly or maintenance is highly likely. Short circuits are probable during disassembly or maintenance, therefore external short-circuit monitoring is necessary. The specific external short-circuit active monitoring process is as follows:

[0057] The MCU controls the active protection MOSFET Q1 to perform periodic opening and closing actions. In this embodiment, a square wave with a period t' of 200ms and a duty cycle of 50% is used to realize the periodic opening and closing of the active protection MOSFET Q1.

[0058] Five more diagnostic tests are required. If all conditions are met, the control action will be executed. The HV2 voltage enters the comparator, which generates a periodic signal by comparing the closed HV2 voltage with a predetermined reference voltage and inputs it into the MCU.

[0059] If the MCU detects that the comparator signal duty cycle is 50%, it indicates an external open circuit. The discharge MOS transistor remains off, and the active protection MOS transistor Q1 remains off, entering the initial state logic for monitoring. In this case, there is no external connection, and the active protection MOS transistor periodically turns on and off. The path from B+ → charging MOS transistor → pre-charge MOS transistor → R1 → active protection MOS transistor Q1 → resistor R2 → B- is periodically switched on and off. The HV2 voltage is affected by resistor R2. Due to the absence of an external equivalent capacitor C, the HV2 voltage changes relatively quickly, varying between the battery voltage V and V*R2 / (R2+R1), with steep rising and falling edges. The duty cycle is set to 50% (second duty cycle setting value), but there is an error when performing duty cycle input capture detection. Therefore, an error value needs to be set: second duty cycle setting value ± error value (second duty cycle), for example, [45%, 55%].

[0060] 3) If the detected duty cycle is in [0%, 40%] or [60%, 100%], it indicates that the external connection is normal, and the diagnostic logic after normal operation is entered. In this case, there is an external connection, and the active protection MOSFET is periodically switched on and off: from B+ → charging MOSFET → pre-charge MOSFET → R1 → active protection MOSFET Q1 → resistor R2 → B-. This circuit is periodically switched on and off. Because there is an external connection, there is an equivalent capacitor. Therefore, a path is also formed from the positive terminal of the capacitor → active protection MOSFET Q1 → resistor R2 → negative terminal of the capacitor. The HV2 voltage is affected by the resistor R2 and the capacitor. The voltage changes between the battery voltage V and V*R2 / (R2+R1). Due to the presence of the capacitor, the rising and falling edges of the voltage change are relatively slow. The duty cycle of the signal detected by the MCU will exceed the predetermined range. For example, the duty cycle is found to be in [0%, 40%] or [60%, 100%].

[0061] 4) After active monitoring is enabled, if the pre-charge current is detected to be greater than 0.6*V / R, that is, 0.6*V / R is the set pre-charge current ratio value, the ratio is 0.6, V is the battery voltage, and R is the pre-charge resistance, the discharge MOS will close immediately; at this time, it indicates that the battery is to be used externally, and in order to meet the external demand, the discharge MOS should be closed immediately.

[0062] Method Implementation Examples:

[0063] An embodiment of an active protection method for external short circuits in a battery protection board is provided. When the battery is in an active state, the pre-charge circuit detects whether the external connection is normal. If the external connection is open, the discharge MOS is actively disconnected until a normal external connection is detected, at which point the discharge MOS is actively closed again. This avoids the risk of external short circuits caused by improper external connection. When the battery is in operation, an active protection circuit is added between the parallel connection point of the discharge switch and the pre-charge circuit and the P- point. This active protection circuit is connected in parallel with a capacitor equivalent to the external load. The magnitude of the discharge current is detected to determine whether active protection needs to be triggered. During active protection, the active protection switch is controlled to periodically open and close. The voltage at the parallel connection point of the discharge switch and the pre-charge circuit is collected and compared with a reference voltage, outputting an output signal containing duty cycle information. The external connection status is determined based on the duty cycle of the output signal, and the opening and closing of the charging switch, discharge switch, pre-charge switch, and active protection switch are controlled according to the external connection status. This method is consistent with the specific active protection process for external short circuits in the battery protection board embodiment, and therefore will not be described again here.

Claims

1. A method for active protection against external short circuits on a battery protection board, characterized in that: The method includes active protection when the battery is in the initial activation state and / or when the battery is in the running state; When the battery is in its first activation state, the following detection logic is executed: 1) Control the pre-charge switch to alternately close and open according to the first duty cycle within the cycle; 2) Detect the pre-charge current and the voltage at point P+; point P+ is the positive connection point for connecting an external load; point P- is the negative connection point for connecting an external load; the external load is equivalent to a capacitor, denoted as the equivalent capacitor; 3) Determine the magnitudes of the pre-charging current and the voltage at point P+, respectively; 4) If the pre-charge current is greater than the set battery current value and the voltage at point P+ is less than the set minimum voltage value, then disconnect the battery discharge switch; the set battery current value is obtained based on the ratio of the battery voltage to the pre-charge resistance. When the battery is in operation, the following operation status detection logic is executed: 1) If the discharge current is less than the current value corresponding to the external static power consumption and has been maintained for a set time, then disconnect the discharge switch, close the pre-charge switch and the charging switch; 2) Control the active protection switch to alternately close and open according to the second duty cycle within the cycle; The active protection switch is connected in parallel between the discharge switch and the pre-charge circuit's parallel connection point and the P- point, and is connected in parallel with the equivalent capacitor; 3) Collect the parallel connection voltage of the discharge switch and the pre-charge circuit, compare the parallel connection voltage with the reference voltage, and output an output signal containing duty cycle information; 4) If the duty cycle in the output signal is within the second duty cycle range, the discharge switch will remain open, the charging switch will remain closed, the active protection switch will remain open, and the initial activation state detection logic will be entered. If the duty cycle in the output signal is not within the second duty cycle range, then close the discharge switch and the charging switch.

2. The active short-circuit protection method for battery protection board according to claim 1, characterized in that: When the battery is in operation, in step 1), if the discharge current is greater than the current value corresponding to the external static power consumption, the discharge switch is closed. The current value corresponding to the external static power consumption is determined according to the external load.

3. The active short-circuit protection method for battery protection board according to claim 1, characterized in that: When the battery is in operation, if the pre-charge current is greater than the set pre-charge current ratio after the discharge switch is turned off and the pre-charge switch and charging switch are turned on, the discharge switch will immediately close and the pre-charge switch and active protection switch will open. The set pre-charge current ratio is determined based on the ratio of battery voltage to pre-charge resistance.

4. The active short-circuit protection method for battery protection board according to claim 1, characterized in that: When the battery is in the initial activation state, in step 4), if the pre-charge current is less than the set zero current approximation and the voltage at P+ is greater than the battery voltage approximation, then the battery discharge switch is turned off; the battery voltage approximation is determined based on the battery voltage.

5. The active short-circuit protection method for battery protection board according to claim 1, characterized in that: When the battery is in the initial activation state, in step 4), if there is a pre-charge current and the voltage at P+ shows an upward trend until the voltage at P+ is greater than the approximate value of the battery voltage, then the pre-charge switch is disconnected and the discharge switch and charging switch are closed.

6. The active short-circuit protection method for battery protection board according to claim 1, characterized in that: If the duty cycle in the output signal is within the second duty cycle range, the discharge switch will remain open, the charging switch will remain closed, the active protection switch will remain open, and the pre-charging current and the voltage at point P+ will be continuously monitored. If the duty cycle in the output signal is not within the first duty cycle range, the discharge current will be continuously monitored after closing the discharge switch and the charging switch.

7. The active short-circuit protection method for a battery protection board according to any one of claims 1 to 6, characterized in that: When the battery is in the initial activation state, the pre-charge current and the voltage at point P+ need to be determined n times. If all n determinations are satisfied, the condition is considered satisfied, and the corresponding switch action is controlled. n≥3.

8. The active short-circuit protection method for a battery protection board according to any one of claims 1 to 6, characterized in that: The range of the second duty cycle is [b-5%, b+5%], where b is the set value of the second duty cycle.

9. A battery protection board, comprising a charging / discharging circuit and a pre-charging circuit, one end of the charging / discharging circuit being connected to a battery and the other end being connected to a load; a discharging switch and a charging switch being connected in series on the charging / discharging circuit; the pre-charging circuit being connected in parallel with the discharging switch; a pre-charging switch being connected in series on the pre-charging circuit; further comprising a microprocessor for controlling the switching of the discharging switch, the charging switch, and the pre-charging switch; characterized in that: The battery protection board also includes an active protection circuit and a comparator; the active protection circuit is connected in parallel between the parallel connection point of the discharge switch and the pre-charge circuit and the P- point, and is connected in parallel with an equivalent capacitor; the P- point is the negative connection point for connecting an external load; the equivalent capacitor is obtained by equivalent connection of the external load; an active protection switch and a protection resistor are connected in series on the active protection circuit; the input terminal of the comparator is connected to the parallel connection point of the discharge switch and the pre-charge circuit, and is used to compare the voltage at the parallel connection point of the discharge switch and the pre-charge circuit with a reference voltage, and output an output signal containing duty cycle information to the microcontroller; Microprocessors are also used for: Active protection when the battery is in the initial activation state and / or when the battery is in operation; When the battery is in an active state, the following detection logic is executed: 1) Control the pre-charge switch to alternately close and open according to the first duty cycle within the cycle; 2) Obtain the pre-charge current and the voltage at point P+; point P+ is the positive connection point used to connect to an external load; 3) Determine the magnitudes of the pre-charging current and the voltage at point P+, respectively; 4) If the pre-charge current is greater than the set battery current value and the voltage at point P+ is less than the set minimum voltage value, then disconnect the battery discharge switch; the set battery current value is obtained based on the ratio of the battery voltage to the pre-charge resistance. When the battery is in operation, the following operation status detection logic is executed: 1) If the discharge current is less than the current value corresponding to the external static power consumption and has been maintained for a set time, then disconnect the discharge switch, close the pre-charge switch and the charging switch; 2) Control the active protection switch to alternately close and open according to the second duty cycle within the cycle; the active protection switch is connected in parallel between the parallel connection point of the discharge switch and the pre-charge circuit and the P- point, and is connected in parallel with the equivalent capacitor; 3) Obtain the output signal containing duty cycle information; 4) If the duty cycle in the output signal is within the second duty cycle range, the discharge switch will remain open, the charging switch will remain closed, the active protection switch will remain open, and the initial activation state detection logic will be entered. If the duty cycle in the output signal is not within the second duty cycle range, then close the discharge switch and the charging switch.

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