Battery dormancy awakening protection circuit applied to energy storage system

Abstract

The utility model provides a battery sleep awakening protection circuit applied to an energy storage system. The battery sleep awakening protection circuit comprises an auxiliary power supply awakening circuit and a BMS module, the BMS module comprises an auxiliary power supply and an MCU control circuit; the auxiliary power supply wake-up circuit is connected with the auxiliary power supply, and the auxiliary power supply is also connected with the lithium battery and the signal sampling unit; wherein when the lithium battery works normally, the auxiliary power supply works normally; and when the lithium battery is in a shutdown state for a preset time or the lithium battery is forbidden to discharge without external energy charging in case of power shortage, the MCU control circuit makes the auxiliary power supply dormant, so that effective protection and reasonable energy management of the battery of the energy storage system are realized.

Description

Technical Field

[0001] This application belongs to the field of battery protection technology, and in particular relates to a protection circuit for waking up a battery from hibernation in an energy storage system. Background Technology

[0002] A Battery Management System (BMS) provides basic management functions including overvoltage, over-discharge, overcurrent, overtemperature, low temperature, short circuit, and capacity monitoring. When a lithium battery energy storage system is shut down for an extended period or the lithium battery is depleted and unable to discharge without external charging, the core control unit (MCU), sampling unit, and protection unit of the BMS module continue to operate, consuming battery energy. Current technology, by activating a low-power mode through the BMS control unit MCU, only reduces energy loss; over time, the battery will still be depleted.

[0003] Therefore, the capacity loss of the battery leads to an increase in lithium battery power consumption and a decrease in the usage time of the device itself in the BMS module. It increases the number of battery charging cycles and reduces the battery life. Especially when the battery is depleted and cannot be discharged and there is no external energy to charge it, it is easy to cause the battery to be over-discharged and depleted due to slow discharge, which can cause irreversible damage to the lithium battery. Utility Model Content

[0004] To address this issue, this application proposes a protection circuit for battery hibernation and wake-up in energy storage systems. When the lithium battery energy storage system is shut down for an extended period or the lithium battery is depleted and unable to discharge without external charging, the BMS module can be put into hibernation. All functional units of the BMS module stop working and cease consuming battery energy. When an external activation signal is received, the BMS module can be reactivated, allowing the entire lithium battery energy storage system to operate normally.

[0005] The battery sleep / wake-up protection circuit described in this application for an energy storage system disconnects the main input power supply circuit to the power PWM chip VCC on the auxiliary power supply of the BMS module. This circuit can only be connected via an optocoupler or a black start switch. When the BMS module needs to sleep, the MCU sends a sleep level signal to pull the COM pin low to shut down the power chip's PWM drive. The auxiliary power supply winding stops outputting to the chip's VCC pin, and the main input power supply circuit to the power PWM chip VCC is also open, thus shutting down the entire auxiliary power supply and putting the BMS module into sleep mode. When the BMS module needs to be woken up, an external level signal is applied to the optocoupler on / off circuit or directly via the black start switch to connect the main input power supply circuit to the power PWM chip VCC. When the VCC voltage reaches the power PWM chip's turn-on voltage, the P chip operates, the auxiliary voltage starts, and the power supply winding supplies power normally. At this point, the entire auxiliary power supply has completed its startup, thus waking up the BMS module.

[0006] Specifically, the protection circuit for battery sleep / wake-up in an energy storage system described in this application includes:

[0007] The circuit includes: an auxiliary power wake-up circuit and a BMS module;

[0008] The BMS module includes an auxiliary power supply and an MCU control circuit.

[0009] The auxiliary power wake-up circuit is connected to the auxiliary power supply, which is also connected to the lithium battery and the signal sampling unit.

[0010] When the lithium battery is working normally, the auxiliary power supply is also working normally; when the lithium battery is in a state of shutdown for a preset time or the lithium battery is depleted and prohibited from discharging and there is no external energy to charge it, the MCU control circuit puts the auxiliary power supply into sleep mode.

[0011] The auxiliary power supply also includes:

[0012] The auxiliary power supply adopts a flyback switching power supply and uses UC2845B as the PWM controller.

[0013] The auxiliary power supply also includes: an auxiliary power supply transformer TX1;

[0014] The auxiliary power transformer TX1 includes a primary winding, a secondary winding, and an auxiliary power supply winding.

[0015] The primary winding is connected to the lithium battery as the energy input part;

[0016] The primary winding is also connected to the drain of the MOSFET Q1. When the flyback switching power supply is working, when the MOSFET Q1 is turned on, the lithium battery provides current to the primary winding, and the electrical energy is stored in the transformer core in the form of magnetic energy.

[0017] When MOSFET Q1 is turned off, the magnetic energy stored in the primary winding is transferred to the secondary winding through electromagnetic induction and then supplies power to the power supply terminal +VCC_BMS through diode D1.

[0018] The auxiliary power supply winding is connected to the Pin7IC_VCC pin of the PWM controller chip via diode D2.

[0019] A capacitor C1 is also connected in parallel between the primary winding and the lithium battery as an input filter capacitor.

[0020] The secondary winding is also connected in parallel with capacitor C2 as an output filter capacitor.

[0021] The diode D2 is also connected in parallel with capacitors C3 and C4 as power supply filter capacitors.

[0022] The MCU control circuit also includes:

[0023] The MCU chip, and capacitor R4 connected to the MCU chip's I / O pins;

[0024] The other end of resistor R4 is connected to the gate (G) of MOSFET Q2. Resistor R4 is also connected in parallel with resistor R5, and the other end of resistor R5 is connected to the source (S) of MOSFET Q2. The drain (D) of MOSFET Q2 is connected to the cathode of optocoupler U2. The anode of optocoupler U2 is connected to the power supply terminal +VCC_BMS via resistor R6.

[0025] The MCU chip can be customized to set sleep conditions;

[0026] When the set sleep condition is triggered, the MCU chip sets it to a high level via the SPS_SD signal;

[0027] The high-level SPS_SD signal drives MOSFET Q2, causing it to output a high-level signal and continue to keep the COMP pin low.

[0028] When the auxiliary power supply stops outputting power to the VCC pin of the PWM controller chip, the BMS module enters a low-power sleep state.

[0029] The auxiliary power wake-up circuit further includes:

[0030] Auxiliary power is activated via the black start switch button;

[0031] When the black start switch button is closed, the auxiliary power input charges capacitors C3 and C4 through resistor R1. When the PWM controller chip reaches its operating voltage, it starts working, the auxiliary power supply starts, and the BMS module begins to work normally.

[0032] The auxiliary power wake-up circuit further includes:

[0033] Current-limiting resistor R7 and optocoupler U4;

[0034] Specifically, by using the external wake-up high-level signal current-limiting resistor R7, the photodiode on the primary side of optocoupler U4 is turned on, thereby controlling the conduction of pins PIN3 and PIN4 on the secondary side of optocoupler U4. The auxiliary power input charges capacitors C3 and C4 through resistor R1. When the PWM controller chip reaches the working voltage, it starts to work, the auxiliary power supply is started, and the BMS module begins to work normally.

[0035] Compared with the prior art, this application has the following beneficial effects:

[0036] This application proposes a battery sleep / wake-up protection circuit for energy storage systems, mainly consisting of three functional circuits: an auxiliary power supply unit, a BMS / MCU sleep circuit, and an auxiliary power supply wake-up circuit. When the lithium battery is operating normally, the auxiliary power supply operates normally, providing energy to the BMS module. When the lithium battery energy storage system is shut down for an extended period or the lithium battery is depleted and unable to discharge without external charging, the BMS / MCU sleep circuit activates the auxiliary power supply to protect against the risk of over-discharge. Furthermore, the BMS / MCU sleep circuit added in this application allows for customizable sleep and wake-up conditions for the lithium battery energy storage system. Users can also define external wake-up high-level settings, or wake the system using a black start switch button, further improving the practicality of the protection circuit. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the battery sleep-wake protection circuit of this application.

[0038] Figure 2 This is the schematic diagram of the auxiliary power supply for this application.

[0039] Figure 3 This is the schematic diagram of the BMS MCU sleep circuit of this application.

[0040] Figure 4 This is the schematic diagram of the auxiliary power supply wake-up circuit of this application. Detailed Implementation

[0041] The following description is intended to disclose this application so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0042] like Figure 1 As shown, the present application describes a protection circuit for battery sleep-wake-up in an energy storage system, the circuit comprising: an auxiliary power wake-up circuit and a BMS module;

[0043] The BMS module includes an auxiliary power supply and an MCU control circuit.

[0044] The auxiliary power wake-up circuit is connected to the auxiliary power supply, which is also connected to the lithium battery and the signal sampling unit.

[0045] When the lithium battery is working normally, the auxiliary power supply is also working normally; when the lithium battery is in a state of shutdown for a preset time or the lithium battery is depleted and prohibited from discharging and there is no external energy to charge it, the MCU control circuit puts the auxiliary power supply into sleep mode.

[0046] like Figure 2 As shown, the auxiliary power supply adopts a flyback switching power supply, preferably using a UC2845B as the PWM controller.

[0047] The auxiliary power supply also includes an auxiliary power transformer TX1, which is the core component of this auxiliary power supply. The auxiliary power transformer TX1 includes a primary winding, a secondary winding, and an auxiliary power supply winding. The primary winding is connected to the lithium battery as the energy input part, providing initial electrical energy to the system.

[0048] When the flyback switching power supply is operating, the lithium battery supplies current to the primary winding when the MOSFET Q1 is turned on. At this time, electrical energy is stored in the transformer core as magnetic energy. Specifically, the lithium battery voltage is applied to the primary winding through the turned-on MOSFET Q1, forming a current loop. The current flows in the primary winding, generating a magnetic field in the transformer core according to the principle of electromagnetic induction, converting electrical energy into stored magnetic energy. To reduce fluctuations in the lithium battery input voltage, a capacitor C1 is connected in parallel between the primary winding and the lithium battery as an input filter capacitor. Capacitor C1 smooths the input voltage, filtering out high-frequency noise and ripple, ensuring a stable voltage input to the primary winding.

[0049] When MOSFET Q1 is turned off, the magnetic energy stored in the primary winding is transferred to the secondary winding through electromagnetic induction. The induced electromotive force in the secondary winding causes current to flow through diode D1, supplying power to the +VCC_BMS terminal. Diode D1 acts as a rectifier, converting the alternating current in the secondary winding into direct current, providing a stable DC voltage to the +VCC_BMS terminal. Simultaneously, to improve output voltage stability, capacitor C2 is connected in parallel with the secondary winding as an output filter capacitor. Capacitor C2 filters the output voltage, reducing ripple and fluctuations, making the voltage output to the +VCC_BMS terminal smoother and more stable.

[0050] The auxiliary power supply winding of the auxiliary power transformer TX1 is connected to the Pin7IC_VCC pin of the PWM controller chip via diode D2. The function of the auxiliary power supply winding is to provide operating power to the PWM controller chip. When the transformer is working, an induced electromotive force is generated in the auxiliary power supply winding, which is rectified by diode D2 to power the PWM controller chip. To ensure the stability of the power supply to the PWM controller chip, capacitors C3 and C4 are connected in parallel with diode D2 as power supply filter capacitors. Capacitors C3 and C4 filter the voltage output from the auxiliary power supply winding, removing high-frequency noise and ripple, thus providing a stable operating voltage for the PWM controller chip.

[0051] The PWM controller chip adjusts the auxiliary power supply output voltage by controlling the on and off times of MOSFET Q1 based on the voltage feedback signal from the +VCC_BMS power supply terminal. When the +VCC_BMS voltage is too high, the PWM controller chip reduces the on-time of MOSFET Q1, thereby reducing the magnetic energy stored in the primary winding and lowering the output voltage of the secondary winding. Conversely, when the +VCC_BMS voltage is too low, the PWM controller chip increases the on-time of MOSFET Q1, increasing the magnetic energy stored in the primary winding and raising the output voltage of the secondary winding. This method achieves precise control of the auxiliary power supply output voltage.

[0052] The auxiliary power supply of this invention, through a rational design of the winding connection method and filter capacitor configuration of the auxiliary power supply transformer, adopts a flyback switching power supply operation mode, effectively converting the electrical energy of the lithium battery into a voltage suitable for electronic devices, thus reducing energy loss. By configuring filter capacitors in the primary winding, secondary winding, and auxiliary power supply winding respectively, ripple and noise in the voltage can be effectively filtered out, ensuring the stability of the output voltage and providing reliable power supply for electronic devices. The auxiliary power supply winding provides an independent operating power supply for the PWM controller chip, and the stability of the power supply is ensured by the filter capacitor, ensuring that the PWM controller chip can accurately control the conduction and cutoff of the MOSFET, achieving precise regulation of the output voltage.

[0053] like Figure 3 As shown, the MCU control circuit further includes:

[0054] The MCU chip, and the resistor R4 connected to the MCU chip's I / O pins;

[0055] The other end of resistor R4 is connected to the gate (G) of MOSFET Q2. Resistor R4 is also connected in parallel with resistor R5, and the other end of resistor R5 is connected to the source (S) of MOSFET Q2. The drain (D) of MOSFET Q2 is connected to the cathode of optocoupler U2. The anode of optocoupler U2 is connected to the power supply terminal +VCC_BMS via resistor R6.

[0056] The MCU chip can be customized to set sleep conditions; preferably, the sleep conditions can be customized according to different application scenarios and requirements. These sleep conditions can be set based on a variety of factors, such as battery level, system operating time, and ambient temperature. For example, when the battery level is lower than a certain set value, or when the system does not receive a valid working command for a period of time, the MCU chip can determine that the sleep condition has been triggered.

[0057] One scenario is that when a set sleep condition is triggered, the MCU chip sets it to a high level via the SPS_SD signal. Specifically, the control logic inside the MCU chip will determine the sleep condition based on the preset condition, and once the condition is met, it will output a high-level SPS_SD signal to its IO pin.

[0058] A high-level SPS_SD signal is transmitted to the gate (G) of MOSFET Q2 through resistor R4, driving MOSFET Q2 to conduct. Since resistors R4 and R5 form the bias circuit for MOSFET Q2, when the SPS_SD signal is high, the gate voltage of MOSFET Q2 increases, causing MOSFET Q2 to conduct. After conduction, MOSFET Q2 outputs a high-level signal and continues to maintain a low state on the COMP pin. The COMP pin here may be a critical control pin in a PWM controller chip or other related circuits; pulling the COMP pin low can change the circuit's operating state, thus affecting the auxiliary power supply output.

[0059] As the COMP pin is pulled low, the auxiliary power supply stops outputting power to the VCC pin of the PWM controller chip. During normal operation, the auxiliary power supply provides a stable operating voltage to the PWM controller chip. When the COMP pin state changes, the auxiliary power supply output is cut off, and the PWM controller chip loses its power supply and cannot continue to operate normally. Since the PWM controller chip plays a crucial control role in the normal operation of the BMS module, when it stops working, the BMS module enters a low-power sleep state, thereby reducing the energy consumption of the entire energy storage system.

[0060] Another scenario is that when the wake-up conditions are met, such as when the battery power recovers to a certain level or the system receives a wake-up command, the MCU chip will set the SPS_SD signal to a low level, the MOSFET Q2 will be turned off, the COMP pin will return to normal, the auxiliary power supply will start outputting power to the VCC pin of the PWM controller chip again, and the BMS module will wake up from the low-power sleep state and resume normal operation.

[0061] Preferably, the hibernation logic of this application is as follows:

[0062]

[0063] like Figure 4 As shown, the auxiliary power wake-up circuit further includes: waking up the auxiliary power supply via a black start switch button. Before waking up the battery, ensure that other related devices in the energy storage system are in normal standby mode, and check whether the black start switch button operates normally. Simultaneously, confirm that the auxiliary power input connection is secure, and that the connections and status of resistors R1, capacitors C3 and C4, as well as the PWM controller chip and BMS module, are normal. The operator manually closes the black start switch button. Once the button is closed, the auxiliary power input begins to function. The current from the auxiliary power input passes through resistor R1, which limits and regulates the current to protect the subsequent capacitors and chips.

[0064] When current flows through resistor R1, it begins to charge capacitors C3 and C4. As energy storage components, capacitors C3 and C4 will gradually accumulate charge.

[0065] During charging, the voltage across the capacitor gradually increases. This charging process is dynamic, and its charging time and speed depend on factors such as the resistance of resistor R1, the capacitance of capacitors C3 and C4, and the voltage input to the auxiliary power supply.

[0066] As capacitors C3 and C4 charge, their voltage gradually increases. When the capacitor voltage causes the PWM (Pulse Width Modulation) controller chip to reach its operating voltage, the PWM controller chip begins to operate normally. The PWM controller chip plays a crucial role in the energy storage system; it can control the output and distribution of power by adjusting the pulse width, ensuring the stable operation of the system.

[0067] After the PWM controller chip starts working, the auxiliary power supply is officially activated. The auxiliary power supply provides stable power to some key components of the entire energy storage system to ensure their normal operation. After the auxiliary power supply starts, the BMS (Battery Management System) module begins normal operation.

[0068] The BMS module is responsible for real-time monitoring and management of the battery's status, including parameters such as battery charge, voltage, and temperature. It controls charging and discharging based on the battery's actual condition and protects the battery from overcharging, over-discharging, overheating, and other abnormal conditions. Once the BMS module is functioning normally, the battery sleep-wake-up process of the entire energy storage system is completed, and the system resumes normal energy storage and power supply functions.

[0069] The wake-up logic is as follows:

[0070]

[0071] The auxiliary power wake-up circuit further includes:

[0072] Current-limiting resistor R7 and optocoupler U4;

[0073] Specifically, by using the external wake-up high-level signal current-limiting resistor R7, the photodiode on the primary side of optocoupler U4 is turned on, thereby controlling the conduction of pins PIN3 and PIN4 on the secondary side of optocoupler U4. The auxiliary power input charges capacitors C3 and C4 through resistor R1. When the PWM controller chip reaches the working voltage, it starts to work, the auxiliary power supply is started, and the BMS module begins to work normally.

[0074] For example, consider a large data center energy storage system that provides backup power for critical equipment such as servers. During normal operation, the batteries in the energy storage system enter a dormant state to save energy and extend battery life. When the mains power fails or the batteries need to be woken up for routine maintenance, an auxiliary power wake-up circuit is used to wake the batteries from dormancy. This auxiliary power wake-up circuit includes a current-limiting resistor R7 and an optocoupler U4. Before performing the wake-up operation, a comprehensive inspection of the entire energy storage system is necessary. This includes confirming that the connections of the current-limiting resistor R7, optocoupler U4, resistor R1, capacitors C3 and C4, the PWM controller chip, and the BMS module are secure and free from looseness or damage. Simultaneously, the auxiliary power input is checked to ensure a stable voltage supply. When the mains power fails or the batteries need to be woken up, the data center's monitoring system sends an external wake-up high-level signal. This signal first passes through the current-limiting resistor R7. The function of the current-limiting resistor R7 is to limit the current flowing into the primary-side photodiode of the optocoupler U4, preventing excessive current from damaging the optocoupler. Based on the specifications of optocoupler U4 and the voltage of the external wake-up high-level signal, the resistance value of the current-limiting resistor R7 is appropriately selected to ensure that the photodiode on the primary side of optocoupler U4 operates within a safe current range. The signal, after being current-limited by the current-limiting resistor R7, turns on the photodiode on the primary side of optocoupler U4. When the photodiode is on, it emits light, which triggers the photosensitive element on the secondary side of optocoupler U4. Upon receiving the light emitted by the primary-side photodiode, the photosensitive element on the secondary side of optocoupler U4 turns on pins PIN3 and PIN4. The optocoupler here provides electrical isolation, separating the external wake-up high-level signal from the auxiliary power input circuit, preventing external signals from interfering with the auxiliary power input circuit. After pins PIN3 and PIN4 on the secondary side of optocoupler U4 are on, the current from the auxiliary power input charges capacitors C3 and C4 through resistor R1. As energy storage elements, capacitors C3 and C4 begin to accumulate charge, and the voltage across them gradually increases. The charging time and speed depend on the resistance of resistor R1, the capacitance of capacitors C3 and C4, and the voltage input to the auxiliary power supply. As capacitors C3 and C4 charge, their voltages continuously increase. When the capacitor voltage reaches the operating voltage of the PWM controller chip, the PWM controller chip begins normal operation. The PWM controller chip is responsible for precisely controlling the output and distribution of power in the energy storage system, ensuring stable system operation. After the PWM controller chip starts working, the auxiliary power supply is officially started. The auxiliary power supply provides stable power support to some key components of the energy storage system, ensuring their normal operation. After the auxiliary power supply starts, the BMS module begins normal operation. The BMS module monitors various battery parameters in real time, such as charge, voltage, and temperature, and performs charging and discharging control according to the actual state of the battery, protecting the battery from abnormal conditions such as overcharging, over-discharging, and overheating.At this point, the batteries of the entire energy storage system have been successfully awakened from their dormant state and restored to normal energy storage and power supply functions.

[0075] Preferably, after the secondary side of optocoupler U4 is turned on, a signal feedback circuit can be added to feed the turn-on signal back to the monitoring system of the data center, so that operators can understand the battery wake-up status in real time.

[0076] Preferably, in addition to the external wake-up high-level signal wake-up method, the previously mentioned wake-up method via the black start switch button can also be retained to increase system reliability and flexibility. Even if the external wake-up high-level signal fails, the battery can still be woken up manually by operating the black start switch button.

[0077] Preferably, a fault detection circuit is added to the circuit to monitor the operating status of components such as current-limiting resistor R7, optocoupler U4, resistor R1, capacitor C3, and capacitor C4 in real time. When a fault is detected in a component, an alarm is issued in a timely manner and corresponding protective measures are taken, such as cutting off the auxiliary power input to prevent the fault from escalating.

[0078] The circuit described in this application further includes a signal sampling unit and a protection unit connected to the auxiliary power supply.

[0079] Preferably, the sampling unit is a sampling resistor or a current transformer. By sampling the voltage and current of the auxiliary power supply in real time, the operating status of the auxiliary power supply can be understood promptly. For example, when the sampled voltage value deviates from the normal range, it may indicate a fault in the auxiliary power supply. Excessive output voltage may damage connected equipment, while insufficient voltage may cause the equipment to malfunction. The voltage and current data collected by the signal sampling unit can be used as feedback signals to adjust the output of the auxiliary power supply. For example, in an auxiliary power supply using switching power supply technology, by sampling the output voltage and feeding it back to the controller, the controller can adjust the on and off times of the switching transistors, thereby achieving stable control of the output voltage.

[0080] Preferably, the protection unit is implemented using a comparator circuit. The sampled auxiliary power supply output voltage is compared with a preset overvoltage threshold. When the sampled voltage exceeds the overvoltage threshold, the comparator outputs a high-level signal, which can trigger a protection action, such as controlling a relay to cut off the auxiliary power supply output or adjusting the power supply control circuit to reduce the output voltage. Similarly, a comparator circuit is used. The sampled voltage is compared with an undervoltage threshold. When the sampled voltage is lower than the undervoltage threshold, the comparator outputs a signal to trigger a protection action. Undervoltage protection can prevent connected equipment from malfunctioning or even experiencing abnormal conditions due to excessively low auxiliary power supply output voltage.

[0081] In summary, the battery sleep / wake-up protection circuit proposed in this application for energy storage systems disconnects the main input power supply loop to the power PWM chip VCC on the auxiliary power supply of the BMS module. This loop can only be connected via an optocoupler or a black start switch. When the BMS module needs to sleep, the MCU sends a sleep level signal to pull the COM pin low to shut down the power chip's PWM drive. The auxiliary power supply winding stops outputting to the chip's VCC pin, and the main input power supply loop to the power PWM chip VCC is also open, thus shutting down the entire auxiliary power supply and putting the BMS module into sleep mode. When the BMS module needs to be woken up, an external level signal is applied to the optocoupler on / off circuit or directly via the black start switch to connect the main input power supply loop to the power PWM chip VCC. When the VCC voltage reaches the power PWM chip's turn-on voltage, the power PWM chip operates, the auxiliary voltage starts, and the power supply winding supplies power normally. At this point, the entire auxiliary power supply has completed its startup, thus waking up the BMS module.

[0082] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A protection circuit for battery sleep / wake-up in an energy storage system, characterized in that, The circuit includes: an auxiliary power wake-up circuit and a BMS module; The BMS module includes an auxiliary power supply and an MCU control circuit. The auxiliary power wake-up circuit is connected to the auxiliary power supply, which is also connected to the lithium battery and the signal sampling unit. When the lithium battery is working normally, the auxiliary power supply is also working normally; when the lithium battery is in a state of shutdown for a preset time or the lithium battery is depleted and prohibited from discharging and there is no external energy to charge it, the MCU control circuit puts the auxiliary power supply into sleep mode.

2. The protection circuit for battery sleep / wake-up in an energy storage system according to claim 1, characterized in that, The auxiliary power supply also includes: The auxiliary power supply adopts a flyback switching power supply and uses UC2845B as the PWM controller.

3. The protection circuit for battery sleep / wake-up in an energy storage system according to claim 2, characterized in that, The auxiliary power supply further includes: an auxiliary power transformer TX1; the auxiliary power transformer TX1 includes a primary winding, a secondary winding and an auxiliary power supply winding.

4. The protection circuit for battery sleep-wake-up in an energy storage system according to claim 3, characterized in that, The auxiliary power supply also includes: The primary winding is connected to the lithium battery as the energy input part; The primary winding is also connected to the drain of the MOSFET Q1. When the flyback switching power supply is working, when the MOSFET Q1 is turned on, the lithium battery provides current to the primary winding, and the electrical energy is stored in the transformer core in the form of magnetic energy.

5. A protection circuit for battery sleep / wake-up in an energy storage system according to claim 4, characterized in that, The auxiliary power supply also includes: When MOSFET Q1 is turned off, the magnetic energy stored in the primary winding is transferred to the secondary winding through electromagnetic induction and then supplies power to the power supply terminal +VCC_BMS through diode D1. The auxiliary power supply winding is connected to the Pin7IC_VCC pin of the PWM controller chip via diode D2.

6. The protection circuit for battery sleep-wake-up in an energy storage system according to claim 5, characterized in that, The auxiliary power supply also includes: A capacitor C1 is also connected in parallel between the primary winding and the lithium battery as an input filter capacitor. The secondary winding is also connected in parallel with capacitor C2 as an output filter capacitor. The diode D2 is also connected in parallel with capacitors C3 and C4 as power supply filter capacitors.

7. A protection circuit for battery sleep / wake-up in an energy storage system according to claim 6, characterized in that, The MCU control circuit also includes: The MCU chip, and capacitor R4 connected to the MCU chip's I / O pins; The other end of resistor R4 is connected to the gate (G) of MOSFET Q2. Resistor R4 is also connected in parallel with resistor R5, and the other end of resistor R5 is connected to the source (S) of MOSFET Q2. The drain (D) of MOSFET Q2 is connected to the cathode of optocoupler U2. The anode of optocoupler U2 is connected to the power supply terminal +VCC_BMS via resistor R6.

8. A protection circuit for battery sleep / wake-up in an energy storage system according to claim 7, characterized in that, The MCU chip can be customized to set sleep conditions; When the set sleep condition is triggered, the MCU chip sets it to a high level via the SPS_SD signal; The high-level SPS_SD signal drives MOSFET Q2, causing it to output a high-level signal and continue to keep the COMP pin low. When the auxiliary power supply stops outputting power to the VCC pin of the PWM controller chip, the BMS module enters a low-power sleep state.

9. A protection circuit for battery sleep / wake-up in an energy storage system according to claim 8, characterized in that, The auxiliary power wake-up circuit further includes: Auxiliary power is activated via the black start switch button; When the black start switch button is closed, the auxiliary power input charges capacitors C3 and C4 through resistor R1. When the PWM controller chip reaches its operating voltage, it starts working, the auxiliary power supply starts, and the BMS module begins to work normally.

10. A protection circuit for battery sleep / wake-up in an energy storage system according to claim 9, characterized in that, The auxiliary power wake-up circuit further includes: Current-limiting resistor R7 and optocoupler U4; Specifically, by using the external wake-up high-level signal current-limiting resistor R7, the photodiode on the primary side of optocoupler U4 is turned on, thereby controlling the conduction of pins PIN3 and PIN4 on the secondary side of optocoupler U4. The auxiliary power input charges capacitors C3 and C4 through resistor R1. When the PWM controller chip reaches the working voltage, it starts to work, the auxiliary power supply is started, and the BMS module begins to work normally.

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