Energy storage device and associated operating method

Abstract

The invention provides an energy storage device and a related operation method. The energy storage device comprises a power line, a battery, a bidirectional switching circuit, a rectifying circuit and a processor. The power line is coupled to a load and is configured to receive an input voltage to power the load using the input voltage. The bidirectional switch circuit includes a first transistor and a second transistor sequentially coupled in series between a power line and a battery. The first transistor and the second transistor are connected back to back. The rectifying circuit is coupled to the first transistor in parallel and is used for conducting when the input voltage is smaller than a voltage threshold value, so that the battery discharges the power line through the second transistor and the rectifying circuit. The processor is coupled to the bidirectional switching circuit and is used for conducting the bidirectional switching circuit to enable the battery to discharge the power line through the first transistor and the second transistor when the input voltage is smaller than a voltage threshold value. According to the energy storage device and the operation method, the power gap can be compensated in time, heat is reduced, and abnormal discharge of the battery is avoided.

Description

Technical Field

[0001] This disclosure relates to power supply technologies, and particularly to energy storage devices that can avoid abnormal discharge and related operation methods. Background Art

[0002] With the increasing demand for remote work and remote teaching and the rise of artificial intelligence technologies, the number of servers and the total power in cloud data centers are continuously increasing. Therefore, most backup power supplies in data centers adopt backup battery modules with instantaneous high-power discharge capabilities. The input voltage provided by the transformer is input to the server through the backup battery module. However, even under normal operating conditions, the input voltage may vary within a certain range. If the input voltage is lower than the discharge voltage of the backup battery module, the backup battery module will discharge abnormally and lose the stored electrical energy. Summary of the Invention

[0003] This disclosure provides an energy storage device, which includes a power line, a battery, a bidirectional switch circuit, a rectifying circuit, and a processor. The power line is used to be coupled to a load and receive an input voltage to supply power to the load using the input voltage. The bidirectional switch circuit includes a first transistor and a second transistor serially coupled in sequence between the power line and the battery. The first transistor and the second transistor are connected back-to-back. The rectifying circuit is coupled in parallel to the first transistor and is used to conduct when the input voltage is less than a voltage threshold, so that the battery discharges to the power line through the second transistor and the rectifying circuit. The processor is coupled to the bidirectional switch circuit and is used to conduct the bidirectional switch circuit when the input voltage is less than the voltage threshold, so that the battery discharges to the power line through the first transistor and the second transistor.

[0004] In some embodiments of the energy storage device, the first transistor is coupled to the second transistor through a first node, and the rectifying circuit includes N diodes. The N diodes are serially coupled between the power line and the first node. N is a positive integer greater than or equal to 2.

[0005] In some embodiments of the energy storage device, the voltage threshold is equal to the discharge voltage of the battery minus the N critical voltages of the N diodes and the critical voltage of the body diode of the second transistor.

[0006] In some embodiments of the energy storage device, the energy storage device further includes a voltage dividing circuit. The voltage dividing circuit is coupled to the power line and is used to divide the input voltage to generate a reference voltage. The processor is used to receive the reference voltage to determine the magnitude relationship between the input voltage and the voltage threshold based on the reference voltage.

[0007] In some embodiments of the energy storage device, the energy storage device further includes a control circuit. The control circuit is coupled to the control terminals of the first transistor, the second transistor, and the processor, and is configured to output a switching signal to control the first transistor and the second transistor. The processor is configured to control the switching signal to switch between different first voltage levels and second voltage levels according to the magnitude relationship between the input voltage and the voltage threshold.

[0008] In some embodiments of the energy storage device, the control circuit includes a third transistor. The third transistor includes a first terminal, a second terminal, and a control terminal. The first terminal of the third transistor is configured to output the switching signal and is coupled to the control terminals of the first transistor and the second transistor. The second terminal of the third transistor is coupled to the ground terminal. The control terminal of the third transistor is coupled to the processor. The processor is configured to control the third transistor to control the switching signal according to the magnitude relationship between the input voltage and the voltage threshold.

[0009] In some embodiments of the energy storage device, the first transistor and the second transistor are P-type transistors, and the source electrode of the first transistor is coupled to the source electrode of the second transistor.

[0010] In some embodiments of the energy storage device, the control circuit includes a charge pump. The charge pump is configured to generate the switching signal and is coupled to the processor, the control terminal of the first transistor, and the control terminal of the second transistor. The processor is configured to control the charge pump to control the switching signal according to the magnitude relationship between the input voltage and the voltage threshold.

[0011] In some embodiments of the energy storage device, the first transistor and the second transistor are N-type transistors, and the drain electrode of the first transistor is coupled to the drain electrode of the second transistor.

[0012] In some embodiments of the energy storage device, when the bidirectional switch circuit is turned on, the rectifying circuit is automatically turned off.

[0013] The present disclosure provides an operation method applicable to an energy storage device. The energy storage device includes a power line, a battery, a bidirectional switch circuit, a rectifying circuit, and a processor. The bidirectional switch circuit includes a first transistor and a second transistor serially coupled in sequence between the power line and the battery, and the first transistor and the second transistor are connected back to back. The rectifying circuit is coupled in parallel to the first transistor. The operation method includes the following steps: receiving an input voltage through the power line and supplying power to a load using the input voltage; automatically turning on the rectifying circuit in response to the input voltage being less than a voltage threshold, so that the battery discharges to the power line through the second transistor and the rectifying circuit; turning on the bidirectional switch circuit using the processor in response to the input voltage being less than the voltage threshold, so that the battery discharges to the power line through the first transistor and the second transistor; and automatically turning off the rectifying circuit in response to the bidirectional switch circuit being turned on.

[0014] In some embodiments of the operation method, the first transistor is coupled to the second transistor through a first node, and the rectifying circuit includes N diodes. The N diodes are serially coupled between the power supply line and the first node. N is a positive integer greater than or equal to 2.

[0015] In some embodiments of the operation method, the voltage threshold is equal to the discharge voltage of the battery minus the N critical voltages of the N diodes and the critical voltage of the body diode of the second transistor.

[0016] In some embodiments of the operation method, the energy storage device further includes a voltage dividing circuit coupled to the power supply line. In response to the input voltage being less than the voltage threshold, turning on the bidirectional switch circuit by the processor includes: using the voltage dividing circuit to divide the input voltage to generate a reference voltage; and using the processor to determine the magnitude relationship between the input voltage and the voltage threshold based on the reference voltage.

[0017] In some embodiments of the operation method, the energy storage device further includes a control circuit. The control circuit is coupled to the control terminal of the first transistor, the control terminal of the second transistor, and the processor. In response to the input voltage being less than the voltage threshold, turning on the bidirectional switch circuit by the processor includes: using the control circuit to output a switching signal to control the first transistor and the second transistor; and using the processor to control the switching signal to switch between different first voltage levels and second voltage levels based on the magnitude relationship between the input voltage and the voltage threshold.

[0018] In some embodiments of the operation method, the control circuit includes a third transistor. The third transistor includes a first terminal, a second terminal, and a control terminal. Using the control circuit to output a switching signal includes: using the first terminal of the third transistor to output a switching signal, where the first terminal of the third transistor is coupled to the control terminal of the first transistor and the control terminal of the second transistor, the second terminal of the third transistor is coupled to the ground terminal, and the control terminal of the third transistor is coupled to the processor; and using the processor to control the third transistor to control the switching signal based on the magnitude relationship between the input voltage and the voltage threshold.

[0019] In some embodiments of the operation method, the first transistor and the second transistor are P-type transistors, and the source of the first transistor is coupled to the source of the second transistor.

[0020] In some embodiments of the operation method, the control circuit includes a charge pump. The charge pump is coupled to the processor, the control terminal of the first transistor, and the control terminal of the second transistor. Using the control circuit to output a switching signal includes: using the charge pump to generate a switching signal; and using the processor to control the charge pump to control the switching signal based on the magnitude relationship between the input voltage and the voltage threshold.

[0021] In some embodiments of the operation method, the first transistor and the second transistor are N-type transistors, and the drain of the first transistor is coupled to the drain of the second transistor.

[0022] Some of the advantages of the above energy storage device and operation method are timely compensation of power gaps, reduction of heat generation, and avoidance of abnormal battery discharge. Brief Description of the Drawings

[0023] Figure 1 It is a simplified functional block diagram of an energy storage device according to an embodiment of the present disclosure.

[0024] Figure 2 It is an operation method according to an embodiment of the present disclosure.

[0025] Figure 3 It is a simplified functional block diagram of an energy storage device according to an embodiment of the present disclosure.

[0026] Description of the Reference Numerals:

[0027] 10: Load

[0028] 20: Power Supply

[0029] 100, 300: Energy Storage Device

[0030] 110, 310: Power Line

[0031] 120, 320: Battery

[0032] 130, 330: Bidirectional Switching Circuit

[0033] 140, 340: Rectifying Circuit

[0034] 150, 350: Processor

[0035] 160, 360: Control Circuit

[0036] 170, 370: Voltage Dividing Circuit

[0037] Vref: Reference Voltage

[0038] Vbat: Discharge Voltage

[0039] Vin: Input Voltage

[0040] Dbd1, Dbd2: Body Diode

[0041] Df1~DfN: Diode

[0042] M1: First Transistor

[0043] M2: Second Transistor

[0044] M3: The third transistor

[0045] R1: The first resistor

[0046] R2: The second resistor

[0047] R3: The third resistor

[0048] R4: The fourth resistor

[0049] R5: The fifth resistor

[0050] R6: The sixth resistor

[0051] Ssw: The switch signal

[0052] N1: The first node

[0053] N2: The second node

[0054] 200: The operation method

[0055] S210~S240: Steps Detailed implementation manners

[0056] The embodiments of the present disclosure document will be described below in conjunction with the relevant drawings. In the drawings, the same reference numerals denote the same or similar elements or method flows.

[0057] Figure 1 FIG. 42 is a simplified functional block diagram of an energy storage device 100 according to an embodiment of the present disclosure document. The energy storage device 100 includes a power line 110, a battery 120, a bidirectional switch circuit 130, a rectifier circuit 140, a processor 150, a control circuit 160, and a voltage dividing circuit 170. The power line 110 is used to couple to an external load 10, where the load 10 may be a combination of a memory and a memory control chip in some embodiments. The power line 110 is also used to receive an input voltage Vin from an external power supply 20 to supply power to the load 10 using the input voltage Vin. The bidirectional switch circuit 130 includes a first transistor M1 and a second transistor M2. The first transistor M1 and the second transistor M2 are sequentially connected in series between the power line 110 and the battery 120, where the first transistor M1 and the second transistor M2 are connected back to back.

[0058] In this embodiment, the first transistor M1 and the second transistor M2 are implemented using P-type transistors. Back-to-back connection means that the first transistor M1 and the second transistor M2 are coupled to each other through the source electrodes. Specifically, the first end (e.g., the drain) of the first transistor M1 is coupled to the power supply line 110, and the second end (e.g., the source) of the first transistor M1 and the body are coupled to the first node N1. The first end (e.g., the drain) of the second transistor M2 is coupled to the battery 120. The second end (e.g., the source) of the second transistor M2 and the body are coupled to the first node N1. The first transistor M1 includes a body diode Dbd1, and the anode terminal and the cathode terminal of the body diode Dbd1 are respectively coupled to the power supply line 110 and the first node N1. The second transistor M2 includes a body diode Dbd2, and the anode terminal and the cathode terminal of the body diode Dbd2 are respectively coupled to the battery 120 and the first node N1.

[0059] The rectifier circuit 140 is coupled in parallel to the first transistor M1 and is configured to conduct when the input voltage Vin is less than a voltage threshold, so that the battery 120 discharges the power supply line 110 through the second transistor M2 (e.g., the body diode Dbd2 of the second transistor M2) and the rectifier circuit 140 to maintain the normal operation of the load 10 for a certain period of time. The rectifier circuit 140 includes N diodes Df1 to DfN, where the diodes Df1 to DfN are connected in series between the power supply line 110 and the first node N1, and N is a positive integer greater than or equal to 2. The aforementioned voltage threshold is related to the critical voltages of the diodes Df1 to DfN, the critical voltage of the body diode Dbd2, and the discharge voltage Vbat of the battery 120, and the voltage threshold can be obtained from the following "Equation 1".

[0060] Vth = Vbat - Vbd2 - N × Vf "Equation 1"

[0061] In the above "Equation 1", "Vth" represents the voltage threshold; "Vbd2" represents the critical voltage of the body diode Dbd2; "Vf" represents the critical voltage of each of the diodes Df1 to DfN. When the input voltage Vin is less than the voltage threshold, the battery 120 discharges the power supply line 110 through the body diode Dbd2 and the diodes Df1 to DfN. Since the discharge voltage Vbat can be determined by the connection method and the number of battery cells, and the critical voltages of the body diode Dbd2 and the diodes Df1 to DfN can be determined by semiconductor processes, the voltage threshold can be determined by "Equation 1" during the circuit design process.

[0062] The processor 150 is coupled to the bidirectional switch circuit 130 through the control circuit 160. The processor 150 is configured to turn on the bidirectional switch circuit 130 when the input voltage Vin is less than the voltage threshold, so that the battery 120 discharges the power supply line 110 through the first transistor M1 and the second transistor M2. Specifically, the voltage dividing circuit 170 is coupled to the power supply line 110 and is configured to divide the input voltage Vin to generate a reference voltage Vref. The voltage dividing circuit 170 includes a first resistor R1 and a second resistor R2, where the first resistor R1 and the second resistor R2 are serially coupled between the power supply line 110 and the ground terminal. A second node N2 between the first resistor R1 and the second resistor R2 is coupled to the processor 150, and the second node N2 is configured to generate the reference voltage Vref. The processor 150 is configured to determine the magnitude of the input voltage Vin based on the reference voltage Vref, and further determine the magnitude relationship between the input voltage Vin and the voltage threshold. As described above, the voltage threshold is a parameter that can be determined during the circuit design process, so the voltage threshold can be stored in advance in the memory of the processor 150.

[0063] It is worth mentioning that when the input voltage Vin is greater than or equal to the voltage threshold, the rectifier circuit 140 will automatically turn off, and the processor 150 will turn off the bidirectional switch circuit 130. Therefore, the turned-off rectifier circuit 140, the turned-off second transistor M2, and the reverse-biased body diode Dbd2 electrically isolate the power supply line 110 from the battery 120.

[0064] The control circuit 160 is coupled to the control terminal (e.g., the gate terminal) of the first transistor M1 and the control terminal (e.g., the gate terminal) of the second transistor M2, and is coupled to the processor 150. The control circuit 160 is configured to output a switching signal Ssw to control the first transistor M1 and the second transistor M2. The processor 150 is configured to control the control circuit 160 based on the magnitude relationship between the input voltage Vin and the voltage threshold, and further control the switching signal Ssw to switch between different first voltage levels (e.g., high voltage levels) and second voltage levels (e.g., low voltage levels).

[0065] Specifically, the control circuit 160 includes a third transistor M3, which is implemented by an N-type transistor in one embodiment. The first end (e.g., the drain terminal) of the third transistor M3 is used to output the switching signal Ssw and is coupled to the control terminals of the first transistor M1 and the second transistor M2. The first end of the third transistor M3 is also coupled to the first node N1 through a third resistor R3. The control terminal (e.g., the gate terminal) of the third transistor M3 is coupled to the processor 150 through a fourth resistor R4, enabling the processor 150 to control the third transistor M3 based on the magnitude relationship between the input voltage Vin and the voltage threshold, and thus control the switching signal Ssw. The control terminal of the third transistor M3 can also be grounded through a fifth resistor R5. The second end (e.g., the source terminal) of the third transistor M3 is coupled to the ground terminal.

[0066] Figure 2 For an operating method 200 according to an embodiment of the present disclosure, where the operating method 200 is applicable to Figure 1 the energy storage device 100. In step S210, through the power line 110, the energy storage device 100 receives the input voltage Vin from the power supply 20, and the power line 110 uses the input voltage Vin to supply power to the load 10.

[0067] In step S220, in response to the input voltage Vin being less than the voltage threshold, the rectifier circuit 140 will automatically turn on, enabling the battery 120 to discharge to the power line 110 through the second transistor M2 (e.g., the body diode Dbd2 of the second transistor M2) and the rectifier circuit 140. For example, the rectifier circuit 140 can turn on when the power supply 20 fails to provide the input voltage Vin, enabling the battery 120 to supply power to the load 10 instead of the power supply 20.

[0068] In step S230, in response to the input voltage Vin being less than the voltage threshold, the processor 150 will turn on the bidirectional switch circuit 130, enabling the battery 120 to discharge to the power line 110 through the first transistor M1 and the second transistor M2. Specifically, the control circuit 160 will output the switching signal Ssw to control the first transistor M1 and the second transistor M2. The voltage dividing circuit 170 will generate a reference voltage Vref, and the processor 150 will determine the magnitude relationship between the input voltage Vin and the voltage threshold based on the reference voltage Vref to control the switching signal Ssw to switch between different first voltage levels (e.g., high voltage levels) and second voltage levels (e.g., low voltage levels).

[0069] More specifically, in step S230, a switching signal Ssw is output from a first end of a third transistor M3 of the control circuit 160. The processor 150 controls the third transistor M3 according to the magnitude relationship between the input voltage Vin and the voltage threshold value to control the switching signal Ssw. When the processor 150 determines that the input voltage Vin is less than the voltage threshold value, the processor 150 turns on the third transistor M3 to switch the switching signal Ssw from a first voltage level to a second voltage level, thereby turning on the first transistor M1 and the second transistor M2.

[0070] In some embodiments, when the processor 150 determines that the input voltage Vin is greater than or equal to the voltage threshold value, the processor 150 turns off the third transistor M3 to maintain the switching signal Ssw at the first voltage level, thereby turning off the first transistor M1 and the second transistor M2. Specifically, the input voltage Vin charges the control terminals of the first transistor M1 and the second transistor M2 through the body diode Dbd1 and the third resistor R3, thereby maintaining the switching signal Ssw at the first voltage level.

[0071] Next, in step S240, when the bidirectional switch circuit 130 is turned on, since the voltage of the power line 110 is close to the voltage of the first node N1, the rectifying circuit 140 automatically turns off.

[0072] It is worth mentioning that the rectifying circuit 140 has a faster response speed to the input voltage Vin than the bidirectional switch circuit 130, but the on-resistance of the rectifying circuit 140 is higher than that of the bidirectional switch circuit 130. Therefore, when the input voltage Vin is less than the voltage threshold value, the rectifying circuit 140 first turns on in step S220 to timely compensate for the power gap, and then in steps S230 - S240, the bidirectional switch circuit 130 turns on and the rectifying circuit 140 turns off to reduce the heat generation during the discharging process. Therefore, the energy storage device 100 can timely compensate for the power gap and reduce the heat generation, and can also prevent the battery 120 from discharging abnormally to the power line 110.

[0073] Figure 3 FIG. is a simplified functional block diagram of an energy storage device 300 according to an embodiment of the present disclosure. The energy storage device 300 includes a power line 310, a battery 320, a bidirectional switch circuit 330, a rectifying circuit 340, a processor 350, a control circuit 360, and a voltage dividing circuit 370. Figure 3 The connection relationships, operations, and advantages of the power line 310, the battery 320, the rectifying circuit 340, the processor 350, and the control circuit 360 are respectively similar to Figure 1 those of the power line 110, the battery 120, the rectifying circuit 140, the processor 150, and the control circuit 160. For the sake of brevity, they will not be repeated here.

[0074] In this embodiment, the first transistor M1 and the second transistor M2 of the bidirectional switch circuit 330 are implemented as N-type transistors. The first end (e.g., the source) of the first transistor M1 is coupled to the main body and connected to the power line 110. The second end (e.g., the drain) of the first transistor M1 is coupled to the rectifier circuit 340 and the second transistor M2 through the first node N1. The first end (e.g., the source) of the second transistor M2 is coupled to the main body and connected to the battery 320. The second end (e.g., the drain) of the second transistor M2 is coupled to the first node N1. In other words, the first transistor M1 and the second transistor M2 are coupled to each other through the drains to achieve a back-to-back connection.

[0075] In this embodiment, the control circuit 360 is implemented as a charge pump. The output terminal of the charge pump is used to generate the switching signal Ssw, and the output terminal of the charge pump is coupled to the control terminal (e.g., the gate) of the first transistor M1 and the control terminal (e.g., the gate) of the second transistor M2, and is also coupled to the ground terminal through the sixth resistor R6. The charge pump is also coupled to the processor 350, where the processor 350 is used to control the charge pump to control the switching signal Ssw according to the magnitude relationship between the input voltage Vin and the voltage threshold.

[0076] The energy storage device 300 can execute Figure 2 the operation method 200. The difference from the content discussed in coordination with the foregoing Figure 2 is that during the process of the energy storage device 300 executing step S230, the charge pump generates the switching signal Ssw, and the processor 150 controls the charge pump to control the switching signal Ssw according to the magnitude relationship between the input voltage Vin and the voltage threshold. Specifically, when the processor 150 determines that the input voltage Vin is less than the voltage threshold, the processor 150 enables the charge pump to charge the control terminals of the first transistor M1 and the second transistor M2. Therefore, the switching signal Ssw switches from the second voltage level (e.g., the low voltage level) to the first voltage level (e.g., the high voltage level), thereby turning on the first transistor M1 and the second transistor M2.

[0077] In some embodiments, when the processor 150 determines that the input voltage Vin is greater than or equal to the voltage threshold, the processor 150 disables the charge pump to maintain the switching signal Ssw at the second voltage level, thereby turning off the first transistor M1 and the second transistor M2. Specifically, the control terminals of the first transistor M1 and the second transistor M2 discharge to the ground terminal through the sixth resistor R6, so that the switching signal Ssw is maintained at the second voltage level.

[0078] In summary, the energy storage device 300 can timely compensate for the power gap and reduce heat generation, and can also prevent the battery 320 from discharging abnormally to the power line 310.

[0079] In the description and claims, certain terms are used to refer to specific elements. However, those skilled in the art should understand that the same element may be referred to by different terms. The description and claims do not distinguish elements by the difference in names, but by the difference in their functions. The term "comprising" mentioned in the description and claims is an open-ended term and should be interpreted as "comprising but not limited to". In addition, "coupled" herein includes any direct and indirect connection means. Therefore, if the text describes that the first element is coupled to the second element, it means that the first element can be directly connected to the second element through electrical connection, wireless transmission, optical transmission or other signal connection means, or indirectly electrically or signal-connected to the second element through other elements or connection means.

[0080] In addition, unless specifically specified in the description, any singular term also includes the plural meaning.

[0081] The above are only the preferred embodiments of this disclosure document. Without departing from the scope or concept of this disclosure document, various modifications and equivalent changes can be made to this disclosure document. In summary, all modifications and equivalent changes made to this disclosure document within the scope of the following claims are covered by this disclosure document.

Claims

1. An energy storage device, characterized in that, Comprising: A power cord for coupling to a load and for receiving an input voltage to supply power to the load using the input voltage; A battery; A bidirectional switch circuit including a first transistor and a second transistor serially coupled in sequence between the power cord and the battery, wherein the first transistor and the second transistor are connected back-to-back; A rectifying circuit parallely coupled to the first transistor and configured to conduct when the input voltage is less than a voltage threshold, enabling the battery to discharge to the power cord through the second transistor and the rectifying circuit; And A processor coupled to the bidirectional switch circuit, configured to conduct the bidirectional switch circuit to enable the battery to discharge to the power cord through the first transistor and the second transistor when the input voltage is less than the voltage threshold.

2. The energy storage device according to claim 1, wherein The first transistor is coupled to the second transistor through a first node, and the rectifying circuit includes: N diodes serially coupled between the power cord and the first node, where N is a positive integer greater than or equal to 2.

3. The energy storage device according to claim 2, wherein The voltage threshold is equal to a discharge voltage of the battery minus N critical voltages of the N diodes and a critical voltage of a body diode of the second transistor.

4. The energy storage device according to claim 1, wherein, Further comprising: A voltage dividing circuit coupled to the power cord for dividing the input voltage to generate a reference voltage, wherein the processor is configured to receive the reference voltage to determine a magnitude relationship between the input voltage and the voltage threshold based on the reference voltage.

5. The energy storage device according to claim 1, characterized in that, Further comprising: A control circuit coupled to a control terminal of the first transistor, a control terminal of the second transistor, and the processor, for outputting a switching signal to control the first transistor and the second transistor, wherein the processor is configured to control the switching signal to switch between a first voltage level and a second voltage level based on the magnitude relationship between the input voltage and the voltage threshold.

6. The energy storage device according to claim 5, characterized in that, The control circuit includes: A third transistor including a first terminal, a second terminal, and a control terminal, wherein the first terminal of the third transistor is configured to output the switching signal and is coupled to the control terminal of the first transistor and the control terminal of the second transistor, wherein the second terminal of the third transistor is coupled to a ground terminal, wherein the control terminal of the third transistor is coupled to the processor, and the processor is configured to control the third transistor to control the switching signal based on the magnitude relationship between the input voltage and the voltage threshold.

7. The energy storage device according to claim 6, characterized in that, The first transistor and the second transistor are P-type transistors, and a source electrode of the first transistor is coupled to a source electrode of the second transistor.

8. The energy storage device according to claim 5, characterized in that, The control circuit includes: A charge pump for generating the switching signal and coupled to the processor, a control terminal of the first transistor, and a control terminal of the second transistor, wherein the processor is configured to control the charge pump to control the switching signal based on the magnitude relationship between the input voltage and the voltage threshold.

9. The energy storage device according to claim 8, characterized in that, The first transistor and the second transistor are N-type transistors, and a drain electrode of the first transistor is coupled to a drain electrode of the second transistor.

10. The energy storage device according to claim 8, characterized in that, When the bidirectional switch circuit is conducted, the rectifying circuit is automatically turned off.

11. An operating method, applicable to an energy storage device, characterized in that, The energy storage device includes a power supply line, a battery, a bidirectional switch circuit, a rectifier circuit, and a processor. The bidirectional switch circuit includes a first transistor and a second transistor serially coupled in sequence between the power supply line and the battery, and the first transistor and the second transistor are connected back-to-back. The rectifier circuit is coupled in parallel to the first transistor. The operation method includes: Receiving an input voltage through the power supply line and supplying power to a load using the input voltage; In response to the input voltage being less than a voltage threshold, automatically turning on the rectifier circuit so that the battery discharges to the power supply line through the second transistor and the rectifier circuit; In response to the input voltage being less than the voltage threshold, using the processor to turn on the bidirectional switch circuit so that the battery discharges to the power supply line through the first transistor and the second transistor; and In response to the bidirectional switch circuit being turned on, automatically turning off the rectifier circuit.

12. The operating method according to claim 11, characterized in that The first transistor is coupled to the second transistor through a first node, and the rectifier circuit includes: N diodes serially coupled between the power supply line and the first node, where N is a positive integer greater than or equal to 2.

13. The operating method according to claim 12, characterized in that, The voltage threshold is equal to a discharge voltage of the battery minus N critical voltages of the N diodes and a critical voltage of a body diode of the second transistor.

14. The operating method according to claim 11, characterized in that, The energy storage device further includes a voltage dividing circuit coupled to the power supply line. In response to the input voltage being less than the voltage threshold, using the processor to turn on the bidirectional switch circuit includes: Using the voltage dividing circuit to divide the input voltage to generate a reference voltage; and Using the processor to determine a magnitude relationship between the input voltage and the voltage threshold based on the reference voltage.

15. The operating method according to claim 11, characterized in that, The energy storage device further includes a control circuit coupled to a control end of the first transistor, a control end of the second transistor, and the processor. In response to the input voltage being less than the voltage threshold, using the processor to turn on the bidirectional switch circuit includes: Using the control circuit to output a switching signal to control the first transistor and the second transistor; And Using the processor to control the switching signal to switch between a first voltage level and a second voltage level based on the magnitude relationship between the input voltage and the voltage threshold.

16. The operating method according to claim 15, characterized in that, The control circuit includes a third transistor having a first end, a second end, and a control end. Using the control circuit to output the switching signal includes: Outputting the switching signal using the first end of the third transistor, where the first end of the third transistor is coupled to the control end of the first transistor and the control end of the second transistor, the second end of the third transistor is coupled to a ground terminal, and the control end of the third transistor is coupled to the processor; And Using the processor to control the third transistor to control the switching signal based on the magnitude relationship between the input voltage and the voltage threshold.

17. The operating method according to claim 16, characterized in that, The first transistor and the second transistor are P-type transistors, and a source of the first transistor is coupled to a source of the second transistor.

18. The operating method according to claim 15, characterized in that, The control circuit includes a charge pump, and the charge pump is coupled to a control terminal of the processor, a control terminal of the first transistor, and a control terminal of the second transistor. Wherein, outputting the switching signal by using the control circuit includes: generating the switching signal by using the charge pump; and controlling the charge pump by using the processor according to a magnitude relationship between the input voltage and the voltage threshold value to control the switching signal.

19. The operating method according to claim 18, wherein, The first transistor and the second transistor are N-type transistors, and a drain of the first transistor is coupled to a drain of the second transistor.

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