Energy storage battery protection circuit, protection board and battery pack

Abstract

The utility model relates to an energy storage battery protection circuit, a protection board and a battery pack, and the energy storage battery protection circuit comprises the energy storage battery protection circuit provided by the embodiment of the utility model can detect that a charging and discharging current is lower than a charging and discharging threshold value (such as a current value indicating that a charging and discharging state is not carried out) through a front-end detection circuit. Controlling the second power supply circuit to close the output of the second power supply voltage and the third power supply voltage, namely automatically entering shallow dormancy; and the control circuit is also used for closing the power supply of the control front-end detection circuit and the control circuit under the condition that the voltage of the energy storage battery is detected to be lower than the under-voltage threshold value, namely entering deep dormancy. Therefore, a corresponding sleep mode can be automatically judged and automatically entered, multi-stage sleep can be realized, normal use and work can be realized, sleep can be entered to save power, the protection board is not easy to be shut down after the electric energy is used up, and the problem that the MCU is always powered on and cannot be turned off can be solved.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology, and in particular to energy storage battery protection circuits, protection boards and battery packs. Background Art

[0002] In electronic products, there are two commonly used circuit design methods for energy storage battery protection boards to solve the problem of self-consumption: one is to only shut down, without a sleep circuit design, all devices are powered by one power supply, and the microcontroller unit (MCU) cannot turn off the peripheral circuit to enter a shallow sleep state, and can only shut down. Therefore, when the energy storage battery protection board is in standby mode, it consumes a lot of power, which is easy to accelerate the discharge of the battery itself, causing the battery to be over-discharged and shut down. The other is a design with a sleep circuit. The MCU has two power supplies, one for a separate LDO (low dropout regulator, low voltage difference linear regulator), and the other is powered by a DC-DC circuit after stepping down and then through the LDO. The power supply of the DC-DC circuit can be cut off during sleep, but because the separate power supply is always powered by the MCU, it will also cause energy loss. And this circuit will not be able to shut down or restart after the MCU crashes abnormally, and manual intervention is required, which brings a lot of trouble. Utility Model Content

[0003] The purpose of the present application is to provide an energy storage battery protection circuit, a protection board and a battery pack, aiming to solve the problem of high energy consumption or inability to shut down the energy storage battery protection board in the related art.

[0004] In a first aspect, an embodiment of the present application provides an energy storage battery protection circuit, which is connected to an energy storage battery and includes:

[0005] A first power supply circuit, connected to the energy storage battery, for providing a first power supply voltage;

[0006] A second power supply circuit, connected to the energy storage battery, for providing a second power supply voltage and a third power supply voltage;

[0007] a communication circuit, connected to the second power supply circuit, and configured to operate under the power supply of the third power supply voltage;

[0008] A front-end detection circuit, connected to the energy storage battery, for detecting the voltage and charge and discharge current of the energy storage battery;

[0009] A control circuit is connected to the first power supply circuit, the second power supply circuit, the communication circuit and the front-end detection circuit, and is used to operate under the power supply of the first power supply voltage or the second power supply voltage, and is used to control the second power supply circuit to shut down the output of the second power supply voltage and the third power supply voltage when the charge and discharge current is lower than the charge and discharge threshold, and is also used to control the front-end detection circuit to shut down and control the first power supply circuit to shut down the output of the first power supply voltage when the voltage of the energy storage battery is lower than the undervoltage threshold.

[0010] In one embodiment, the first power supply circuit includes a first voltage conversion module and a first switch module, the first voltage conversion module and the first switch module are connected in series between the positive electrode of the energy storage battery and the power supply port of the control circuit, and the first voltage conversion module is used to convert the voltage output by the energy storage battery into the first supply voltage.

[0011] In one embodiment, the second power supply circuit includes a second voltage conversion module, a third voltage conversion module, a fourth voltage conversion module and a second switch module, wherein:

[0012] The second voltage conversion module is connected to the positive electrode of the energy storage battery and the control circuit, and is used to convert the voltage output by the energy storage battery into a first voltage;

[0013] The third voltage conversion module and the second switch module are connected in series between the second voltage conversion module and the power supply port of the control circuit, and the third voltage conversion module is used to convert the first voltage into the second power supply voltage; the second switch module is also connected to the control circuit, and is used to turn on or off the second power supply voltage to the power supply port of the control circuit according to the control of the control circuit;

[0014] The fourth voltage conversion module is connected to the second voltage conversion module and the communication circuit, and is used to convert the first voltage into the third power supply voltage and supply it to the communication circuit.

[0015] In one embodiment, the communication circuit includes an R485 port circuit and / or a UART port circuit.

[0016] In one embodiment, a charging detection circuit is further included, wherein the charging detection circuit is connected to the positive electrode of the energy storage battery, the control circuit, and the second power supply circuit, and the charging detection circuit is used to generate an enable signal to the second power supply circuit when a charger is connected, and the enable signal is used to enable the second power supply circuit to operate.

[0017] In one embodiment, the charging detection circuit includes a first NPN transistor, a second NPN transistor, a first PNP transistor, a first voltage divider resistor, a first bias resistor, a second bias resistor, a third bias resistor, a first diode and a second diode, wherein:

[0018] The emitter of the first NPN transistor is connected to the charging interface through the first diode, the first bias resistor is connected between the base and the emitter of the first NPN transistor, the emitter of the first NPN transistor is also grounded through the first voltage-dividing resistor, the collector of the first NPN transistor is connected to the base of the first PNP transistor, the second bias resistor is connected between the base and the collector of the first PNP transistor, the collector of the first PNP transistor is connected to the positive electrode of the energy storage battery, the collector of the first PNP transistor is connected to the base of the second NPN transistor and the anode of the second diode, the third bias resistor is connected between the base and the emitter of the second NPN transistor, the emitter of the second NPN transistor is grounded, and the collector of the second NPN transistor is connected to the first supply voltage and is connected to the control circuit;

[0019] The cathode of the second diode is connected to the second power supply circuit, and is used to output the first enable signal.

[0020] In one embodiment, the front-end detection circuit includes a detection module and a sampling resistor, the sampling resistor is connected in series to the negative electrode of the energy storage battery, the detection module is connected to both ends of the sampling resistor, and is used to sample the charge and discharge current; the detection module is also connected to the energy storage battery, and is used to sample the voltage of the energy storage battery.

[0021] In one embodiment, it also includes a charging MOS tube and a discharging MOS tube, wherein the charging MOS tube and the discharging MOS tube are connected in series to the negative electrode of the energy storage battery, and the detection module is also connected to the charging MOS tube and the discharging MOS tube, and is also used to control the conduction and cutoff of the charging MOS tube and the discharging MOS tube.

[0022] In a second aspect, an embodiment of the present application further provides an energy storage battery protection board, comprising the above-mentioned energy storage battery protection circuit.

[0023] In a third aspect, an embodiment of the present application further provides a battery pack, comprising an energy storage battery and the energy storage battery protection board as described above.

[0024] Compared with the related art, the embodiment of the present application has the following beneficial effects: the energy storage battery protection circuit provided by the embodiment of the present application can detect that the charge and discharge current is lower than the charge and discharge threshold value (for example, the current value indicating that the charge and discharge state is not in progress) through the front-end detection circuit, and control the second power supply circuit to shut down the output of the second power supply voltage and the third power supply voltage, that is, automatically enter shallow sleep; it is also used to shut down the power supply of the control front-end detection circuit and the control circuit when it is detected that the voltage of the energy storage battery is lower than the undervoltage threshold, that is, enter deep sleep. In this way, it can automatically determine and automatically enter the corresponding sleep mode, and can achieve multi-level sleep, that is, it can work normally and enter sleep to save power, it is not easy to let the protection board run out of power and shut down, and it can solve the problem that the MCU is always powered on and cannot be shut down. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a module of an energy storage battery protection circuit provided in an embodiment of the present application;

[0026] Figure 2 for Figure 1 A schematic diagram of a module of a first power supply circuit in an energy storage battery protection circuit is shown;

[0027] Figure 3 for Figure 1 A circuit diagram of a first power supply circuit in an energy storage battery protection circuit is shown;

[0028] Figure 4 for Figure 1 A schematic diagram of a module of a second power supply circuit in an energy storage battery protection circuit is shown;

[0029] Figure 5 for Figure 4 A circuit diagram of a second voltage conversion module in a second power supply circuit is shown;

[0030] Figure 6 for Figure 4 A circuit diagram of a third voltage conversion module in a second power supply circuit is shown;

[0031] Figure 7 for Figure 4 A circuit diagram of a second switch module in a second power supply circuit is shown;

[0032] Figure 8 for Figure 4 A circuit diagram of a fourth voltage conversion module in the second power supply circuit shown;

[0033] Fig. 9 for Figure 1 The circuit diagram of the charging detection circuit in the energy storage battery protection circuit is shown. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0036] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0038] like Figure 1 As shown, an embodiment of the present application provides an energy storage battery protection circuit that can be applied to an energy storage battery protection board or a battery pack. The energy storage battery protection circuit is connected to the energy storage battery 100, and includes a first power supply circuit 110, a second power supply circuit 120, a communication circuit 130, a front-end detection circuit 140 and a control circuit 150.

[0039] The first power supply circuit 110 is connected to the energy storage battery 100 to provide a first power supply voltage V1; the second power supply circuit 120 is connected to the energy storage battery 100 to provide a second power supply voltage V2 and a third power supply voltage V3. The communication circuit 130 is connected to the second power supply circuit 120 to work under the power supply of the third power supply voltage V3. The front-end detection circuit 140 is connected to the energy storage battery 100 to detect the voltage and charge and discharge current of the energy storage battery 100. The control circuit 150 is connected to the first power supply circuit 110, the second power supply circuit 120, the communication circuit 130 and the front-end detection circuit 140 to work under the power supply of the first power supply voltage V1 or the second power supply voltage V2, and to control the second power supply circuit 120 to turn off the output of the second power supply voltage V2 and the third power supply voltage V3 when the charge and discharge current is lower than the charge and discharge threshold, and to control the front-end detection circuit 140 to turn off and control the first power supply circuit 110 to turn off the output of the first power supply voltage V1 when the voltage of the energy storage battery 100 is lower than the undervoltage threshold.

[0040] Among them, the control circuit 150 is, for example, a BMS (Battery Management System) chip, and the charge and discharge threshold can be set to, for example, a current value in a static state. If the charge and discharge current is lower than the charge and discharge threshold, it means that the energy storage battery 100 is in a static state without charging or discharging.

[0041] Optionally, when the front-end detection circuit 140 detects that the energy storage battery 100 is in a static state, for example, after this state is maintained for 5 minutes, the control circuit 150 outputs a control signal to control the charge and discharge current to be lower than the charge and discharge threshold, and controls the second power supply circuit 120 to turn off the output of the second power supply voltage V2 and the third power supply voltage V3. That is, the communication circuit 130 and the second voltage supply to the control circuit 150 are turned off, and the control circuit 150 only works under the power supply of the first power supply circuit 110 and enters a shallow sleep state.

[0042] In one example, after the control circuit 150 turns off the output of the second power supply circuit 120, the front-end detection circuit 140 still works and can still implement overcharge protection, over-discharge protection, overcurrent protection, short circuit protection, temperature protection, and balance protection. The whole machine consumes about 300uA, which saves the energy of the energy storage battery 100 and allows the energy storage battery 100 to work for a long time without damaging the battery cell due to underpowering. After entering shallow sleep, there are 4 ways to activate back to normal working mode: 1. Activate through a weak current switch; 2. Activate through an external signal from the communication circuit 130; 3. Activate by charging; 4. Activate when the discharge current is greater than a certain value; 5. Wake up at a scheduled time.

[0043] When the voltage of the energy storage battery 100 reaches a low voltage, the control circuit 150 2The C communication control front-end detection circuit 140 also enters the sleep mode (for example, shut down), the control circuit 150 shuts down and enters deep sleep, the energy storage battery 100 protection circuit no longer works, and the current consumption is extremely small at this time, only less than 20UA, and even if it is left for a long time, it will not damage the battery cell due to over-discharge. At this time, only charging can activate the energy storage battery 100 protection circuit to stop working and return to the normal working mode.

[0044] The energy storage battery protection circuit includes a discharge MOS tube 160 and a charge MOS tube 170. The charge MOS tube 170 and the discharge MOS tube 160 are connected in series to the negative electrode of the energy storage battery 100. The front-end detection circuit 140 is also connected to the charge MOS tube 170 and the discharge MOS tube 160, and is also used to control the conduction and cutoff of the charge MOS tube 170 and the discharge MOS tube 160. For example, when the energy storage battery 100 is charged and discharged, the front-end detection circuit 140 controls the conduction of the charge MOS tube 170 and the discharge MOS tube 160. When the energy storage battery 100 is overcharged, over-discharged, over-current, short-circuited, over-temperatured, etc., the front-end detection circuit 140 controls the charge MOS tube 170 and / or the discharge MOS tube 160 to be cut off.

[0045] The energy storage battery protection circuit is in the normal working mode. The energy storage battery protection circuit is charged by solar energy or a charger, or is discharging the load. The control circuit 150 and the front-end detection circuit 140 are both working normally. The charging MOS tube 170 and the discharging MOS tube 160 are both in the on state. The energy storage battery 100 can be charged and discharged normally. The energy storage battery protection circuit has protection functions such as overcharge protection, over-discharge protection, overcurrent protection, short circuit protection, temperature protection, and equalization protection. At the same time, the energy storage battery protection circuit communicates with the communication circuit 130. Exemplarily, in this normal working mode, the above functions need to be maintained normally, and the energy consumption is about 20mA.

[0046] See also Figure 2 In one embodiment, the first power supply circuit 110 includes a first voltage conversion module 112 and a first switch module 114, which are connected in series between the positive electrode B+ of the energy storage battery 100 and the power supply port of the control circuit 150, and the first voltage conversion module 112 is used to convert the voltage output by the energy storage battery 100 into a first power supply voltage V1. It should be noted that the VCC_PWO signal is a charger input voltage signal.

[0047] The first voltage conversion module 112 may be implemented as follows: Figure 2 The step-down circuit is composed of discrete components shown in FIG. 1. In other embodiments, the first voltage conversion module 112 may also directly use an LDO chip.

[0048] See also Figure 3The step-down circuit includes NPN transistors Q1 / Q2 / Q3 and a voltage-stabilizing diode D1. The collector of the NPN transistor Q1 is connected to the positive electrode B+ of the energy storage battery 100 through a resistor R1, and the base is connected to the positive electrode B+ of the energy storage battery 100 through a resistor R2. The base of the NPN transistor Q1 is connected to the cathode of the voltage-stabilizing tube D1, and the anode of the voltage-stabilizing tube D1 is grounded. The base of the NPN transistor Q1 is also connected to a filter capacitor C1, and the emitter of the NPN transistor Q1 is connected to the base of the NPN transistor Q2. The collector of the NPN transistor Q2 is connected to the cathode of the voltage-stabilizing tube D1 through resistors R3 and R4. Connected to the positive electrode of the energy storage capacitor, the emitter of the NPN transistor Q2 is connected to the collector of the NPN transistor Q3 through the resistor R5, the emitter of the NPN transistor Q2 is also grounded through the capacitor C2, capacitors C3 and C4 are connected between the collector and base of the NPN transistor Q3, the base of the NPN transistor Q3 is grounded, the emitter of the NPN transistor Q3 is grounded through the capacitors C5 and C6, and is connected to the first switch module 114 as the output end of the first voltage conversion module 112.

[0049] In an example, the first switch module 114 includes an NPN transistor Q4 and a P-channel MOS transistor Q5, the base of the NPN transistor Q4 serves as the control end of the first switch module 114 for receiving the control signal PWR_SEL of the control circuit 150, the base of the NPN transistor Q4 is connected to the control circuit 150 through a resistor R6, a resistor R7 is connected between the base and the emitter of the NPN transistor Q4, the collector of the NPN transistor Q4 is connected to the gate of the P-channel MOS transistor Q5 through a resistor R8, the source of the P-channel MOS transistor Q5 is connected to the output end of the first voltage conversion module 112, a resistor R9 is connected between the source and the gate of the P-channel MOS transistor Q5, and the drain of the P-channel MOS transistor Q5 serves as the output end of the first power supply circuit 110.

[0050] See also Figure 4 In one embodiment, the second power supply circuit 120 includes a second voltage conversion module 122 , a third voltage conversion module 124 , a fourth voltage conversion module 126 and a second switch module 128 .

[0051] The second voltage conversion module 122 is connected to the positive electrode B+ of the energy storage battery 100 and the control circuit 150, and is used to convert the voltage output by the energy storage battery 100 into the first voltage SYS_5V. The third voltage conversion module 124 and the second switch module 128 are connected in series between the second voltage conversion module 122 and the power supply port of the control circuit 150. The third voltage conversion module 124 is used to convert the first voltage SYS_5V into the second power supply voltage V2; the second switch module 128 is also connected to the control circuit 150, and is used to turn on or off the second power supply voltage V2 to the power supply port of the control circuit 150 according to the control of the control circuit 150. The fourth voltage conversion module 126 is connected to the second voltage conversion module 122 and the communication circuit 130, and is used to convert the first voltage SYS_5V into the third power supply voltage V3, and supply it to the communication circuit 130.

[0052] In one example, the second voltage conversion module 122 is as follows: Figure 5 As shown, it includes a DC-DC conversion circuit based on a DC-DC control chip U12. The third voltage conversion module 124 is as shown in FIG. Figure 6 As shown, it includes an LDO chip U13. The second switch module 128 is as shown in FIG. Figure 7 As shown, it includes a P-channel MOS transistor Q6, the source of the P-channel MOS transistor Q6 is connected to the output end of the third voltage conversion module 124, the source and gate of the P-channel MOS transistor Q5 are connected to a resistor R11, the gate of the P-channel MOS transistor Q5 is connected to the control circuit 150 through a resistor R10, and the drain of the P-channel MOS transistor Q5 serves as one of the output ends of the second power supply circuit 120 to output the second power supply voltage V2. The fourth voltage conversion module 126 is as shown in FIG. Figure 8 As shown, it mainly includes an isolated power supply U14 and a LEO chip U10.

[0053] In one embodiment, the communication circuit 130 includes an R485 port circuit and / or a UART port circuit.

[0054] See also Figure 1 In one embodiment, the energy storage battery protection circuit also includes a charging detection circuit 180, which is connected to the positive electrode B+ of the energy storage battery 100, the control circuit 150, and the second power supply circuit 120. The charging detection circuit 180 is used to generate an enable signal to the second power supply circuit 120 when the charger is connected, and the enable signal is used to enable the second power supply circuit 120 to work.

[0055] In one embodiment, the charging detection circuit 180 includes a first NPN transistor Q21, a second NPN transistor Q22, a first PNP transistor Q20, a first voltage divider resistor R184, a first bias resistor R183, a second bias resistor R180, a third bias resistor R174, a first diode D4 and a second diode D5, wherein:

[0056] The emitter of the first NPN transistor Q21 is connected to the pin P- / C- of the charging interface through the first diode D4, the first bias resistor R183 is connected between the base and the emitter of the first NPN transistor Q21, the emitter of the first NPN transistor Q21 is also grounded through the first voltage-dividing resistor R184, the collector of the first NPN transistor Q21 is connected to the base of the first PNP transistor Q20, the second bias resistor R180 is connected between the base and the collector of the first PNP transistor Q20, and the collector of the first PNP transistor Q20 is grounded. The positive electrode B+ of the energy storage battery 100 is connected, the collector of the first PNP transistor Q20 is connected to the base of the second NPN transistor Q22 and the anode of the second diode D5, the third bias resistor R174 is connected between the base and the emitter of the second NPN transistor Q22, the emitter of the second NPN transistor Q22 is grounded, the collector of the second NPN transistor Q22 is connected to the first power supply voltage V1, and is connected to the control circuit 150; the cathode of the second diode D5 is connected to the second power supply circuit 120, and is used to output the enable signal DC-DC_EN. The enable signal DC-DC_EN is used to enable the second power supply circuit 120 to work.

[0057] In one embodiment, the front-end detection circuit 140 includes a detection module and a sampling resistor, the sampling resistor is connected in series to the negative electrode B- of the energy storage battery 100, and the detection module is connected to both ends of the sampling resistor for sampling the charge and discharge current; the detection module is also connected to the energy storage battery 100 for sampling the voltage of the energy storage battery 100. The detection module is also connected to the charging MOS tube 170 and the discharging MOS tube 160, and is also used to control the conduction and cutoff of the charging MOS tube 170 and the discharging MOS tube 160.

[0058] Combination Figures 3 to 9 , explain in detail the working principle of the energy storage battery protection circuit:

[0059] Normal working mode: When the charger is plugged in, the first NPN transistor Q21 of the charger detection circuit 180 is turned on, triggering Q20 to turn on, and outputting a high-level enable signal DC-DC_EN to the control pin EN of the DC-DC control chip U12 of the second voltage conversion module 122. The DC-DC control chip U12 starts working and outputs 5V (first voltage SYS_5V) DC power. The 5V DC power is stepped down to 3.3V (V2) by the LDO chip U2 of the third voltage conversion module 124 and then supplied to the control circuit 150. The control circuit 150 works after being powered on. The two IO ports SYS_POW_EN (see Fig. 9 ), MCU_OFF (see Figure 3 ) both output high level, self-locking the control pin EN of the DC-DC control chip U12 to keep all parts of the circuit working normally.

[0060] Shallow sleep mode: When it is detected that there is neither charging nor discharging and this state is maintained for 5 minutes, the IO port SYS_POW_EN of the control circuit 150 becomes low level, the DC-DC control chip U12 is controlled to be turned off, and the DC-DC control chip U12 has no voltage output. At the same time, the PWR_SEL of the IO port of the control circuit 150 will also become high level, resulting in no output of the second power supply voltage V2 and the third power supply voltage V3, and the isolation power supply U14 and the communication circuit 130 are turned off to reduce energy consumption. Only the power supply of the control circuit 150 is retained, and the control circuit 150 is in a shallow sleep mode. At this time, the current of the whole machine is less than 300UA.

[0061] Deep sleep mode: When the front-end detection circuit 140 detects that the voltage of a single battery or the total voltage is lower than the undervoltage threshold, the IO ports SYS_POW_EN and MCU_OFF of the control circuit 150 both output low levels, turning off the input power of all circuits. At this time, the circuit current of the entire machine is less than 20uA. Even if there is no power replenishment for a long time, the energy storage battery 100 will not be damaged due to over-discharge.

[0062] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A storage battery protection circuit, connected to a storage battery, characterized in that: include: A first power supply circuit, connected to the energy storage battery, for providing a first power supply voltage; A second power supply circuit, connected to the energy storage battery, for providing a second power supply voltage and a third power supply voltage; a communication circuit, connected to the second power supply circuit, and configured to operate under the power supply of the third power supply voltage; A front-end detection circuit, connected to the energy storage battery, for detecting the voltage and charge and discharge current of the energy storage battery; A control circuit is connected to the first power supply circuit, the second power supply circuit, the communication circuit and the front-end detection circuit, and is used to operate under the power supply of the first power supply voltage or the second power supply voltage, and is used to control the second power supply circuit to shut down the output of the second power supply voltage and the third power supply voltage when the charge and discharge current is lower than the charge and discharge threshold, and is also used to control the front-end detection circuit to shut down and control the first power supply circuit to shut down the output of the first power supply voltage when the voltage of the energy storage battery is lower than the undervoltage threshold.

2. The energy storage battery protection circuit according to claim 1, characterized in that: The first power supply circuit includes a first voltage conversion module and a first switch module. The first voltage conversion module and the first switch module are connected in series between the positive electrode of the energy storage battery and the power supply port of the control circuit. The first voltage conversion module is used to convert the voltage output by the energy storage battery into the first supply voltage.

3. The energy storage battery protection circuit according to claim 1, characterized in that: The second power supply circuit includes a second voltage conversion module, a third voltage conversion module, a fourth voltage conversion module and a second switch module, wherein: The second voltage conversion module is connected to the positive electrode of the energy storage battery and the control circuit, and is used to convert the voltage output by the energy storage battery into a first voltage; The third voltage conversion module and the second switch module are connected in series between the second voltage conversion module and the power supply port of the control circuit, and the third voltage conversion module is used to convert the first voltage into the second power supply voltage; the second switch module is also connected to the control circuit, and is used to turn on or off the second power supply voltage to the power supply port of the control circuit according to the control of the control circuit; The fourth voltage conversion module is connected to the second voltage conversion module and the communication circuit, and is used to convert the first voltage into the third power supply voltage and supply it to the communication circuit.

4. The energy storage battery protection circuit according to claim 1, characterized in that: The communication circuit includes an R485 port circuit and / or a UART port circuit.

5. The energy storage battery protection circuit according to any one of claims 1 to 4, characterized in that: It also includes a charging detection circuit, which is connected to the positive electrode of the energy storage battery, the control circuit, and the second power supply circuit. The charging detection circuit is used to generate an enable signal to the second power supply circuit when the charger is connected, and the enable signal is used to enable the second power supply circuit to operate.

6. The energy storage battery protection circuit according to claim 5, characterized in that: The charging detection circuit includes a first NPN transistor, a second NPN transistor, a first PNP transistor, a first voltage-dividing resistor, a first bias resistor, a second bias resistor, a third bias resistor, a first diode and a second diode, wherein: The emitter of the first NPN transistor is connected to the charging interface through the first diode, the first bias resistor is connected between the base and the emitter of the first NPN transistor, the emitter of the first NPN transistor is also grounded through the first voltage-dividing resistor, the collector of the first NPN transistor is connected to the base of the first PNP transistor, the second bias resistor is connected between the base and the collector of the first PNP transistor, the collector of the first PNP transistor is connected to the positive electrode of the energy storage battery, the collector of the first PNP transistor is connected to the base of the second NPN transistor and the anode of the second diode, the third bias resistor is connected between the base and the emitter of the second NPN transistor, the emitter of the second NPN transistor is grounded, and the collector of the second NPN transistor is connected to the first supply voltage and is connected to the control circuit; The cathode of the second diode is connected to the second power supply circuit for outputting the enable signal.

7. The energy storage battery protection circuit according to claim 1, characterized in that: The front-end detection circuit includes a detection module and a sampling resistor, the sampling resistor is connected in series to the negative electrode of the energy storage battery, the detection module is connected to both ends of the sampling resistor, and is used to sample the charge and discharge current; the detection module is also connected to the energy storage battery, and is used to sample the voltage of the energy storage battery.

8. The energy storage battery protection circuit according to claim 7, characterized in that: It also includes a charging MOS tube and a discharging MOS tube, which are connected in series to the negative electrode of the energy storage battery. The detection module is also connected to the charging MOS tube and the discharging MOS tube, and is also used to control the conduction and cutoff of the charging MOS tube and the discharging MOS tube.

9. A storage battery protection board, characterized in that: It comprises the energy storage battery protection circuit as described in any one of claims 1 to 8.

10. A battery pack, characterized in that: It comprises an energy storage battery and the energy storage battery protection plate as claimed in claim 9.

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