CN219960208U

CN219960208U - Protection circuit and vehicle

Info

Publication number: CN219960208U
Application number: CN202322058369.5U
Authority: CN
Inventors: 黄熠; 叶伏明; 郭茂柏
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-08-02
Filing date: 2023-08-02
Publication date: 2023-11-03
Anticipated expiration: 2033-08-02

Abstract

The utility model discloses a protection circuit and a vehicle. The protection circuit includes: a first electrical unit; the first end of the current limiting module is connected with the constant electric power supply, and the second end of the current limiting module is connected with the first electric unit; the current limiting module is used for limiting the current direction to be unidirectional from the first end to the second end; the constant electric power supply is used for supplying power to the first electric unit; the first energy storage module is connected between the current limiting module and the first electric unit and is used for assisting in supplying power to the first electric unit. According to the embodiment of the utility model, when the normal electric power supply is powered down, the energy storage module can be utilized to release the pre-stored electric quantity to the first electric unit for supplying power, and the energy storage module is prevented from supplying power to other second electric units, so that the first electric unit can continue to operate after the circuit breaking abnormality occurs.

Description

Protection circuit and vehicle

Technical Field

The present utility model relates to the field of power management technologies, and in particular, to a protection circuit and a vehicle.

Background

With the development of new energy technology, batteries are increasingly used in various electric devices, such as mobile phones, notebook computers, battery cars, electric automobiles, electric airplanes, electric ships, and the like.

In the operation process of the power utilization device, the power supply can supply power for each power utilization unit, so that each power utilization unit can keep normal operation. However, when a short-term disconnection abnormality occurs in a current loop between the power supply and the electricity consumption unit, the electricity consumption unit cannot continue to operate normally.

Disclosure of Invention

The embodiment of the utility model provides a protection circuit and a vehicle, which can solve the technical problem that an electricity utilization unit cannot continue to operate when a transient abnormality occurs between a power supply and the electricity utilization unit.

In a first aspect, an embodiment of the present utility model provides a protection circuit, including:

a first electrical unit;

the first end of the current limiting module is connected with the constant electric power supply, and the second end of the current limiting module is connected with the first electric unit; the current limiting module is used for limiting the current direction to be unidirectional from the first end to the second end; the constant electric power supply is used for supplying power to the first electric unit;

the first energy storage module is connected between the current limiting module and the first electric unit and is used for assisting in supplying power to the first electric unit.

By arranging the current limiting module, the current can be limited to flow unidirectionally by the current limiting module. When a current loop between the constant power supply and the first power unit is in disconnection abnormality, the first energy storage module can release stored electric quantity to supply power for the first power unit. The current limiting module can limit the charge released by the first energy storage module to flow to only the first electric unit. The first energy storage module is limited to supply power for the first power unit only, and does not supply power for the second power unit, so that the first power unit can continue to operate after the circuit breaking abnormality occurs.

In one possible implementation manner of the first aspect, the current limiting module includes: the positive electrode of the first diode is connected with a constant electric power supply, and the negative electrode of the first diode is connected with the first electric unit. The unidirectional current flow can be realized by arranging the first diode, and the energy storage module is prevented from supplying power to the second power utilization unit on the basis that the normal power supply is not influenced to supply power to the first power utilization unit.

In one possible implementation manner of the first aspect, the current limiting module includes: the first MOS tube is connected between the constant electric power supply and the first electric unit and comprises a body diode, the positive electrode of the body diode is connected with the constant electric power supply, and the negative electrode of the body diode is connected with the first electric unit. The unidirectional current flow can be realized by arranging the first MOS tube, and the energy storage module is prevented from supplying power to the second power utilization unit on the basis that the normal power supply is not influenced to supply power to the first power utilization unit.

In a possible implementation manner of the first aspect, the first energy storage module includes: the first end of the first energy storage capacitor is connected between the second end of the current limiting module and the first electric unit, and the second end of the first energy storage capacitor is grounded. The first energy storage capacitor is arranged to store and discharge electric charge so as to continuously supply power to the first electric unit when the current loop is in open circuit abnormality.

In a possible implementation manner of the first aspect, the first energy storage module includes: the first end of the first resistor is connected with the second end of the current limiting module; at least one second energy storage capacitor, the first end of the second energy storage capacitor is connected with the second end of the first resistor, and the second end of the second energy storage capacitor is grounded. The first resistor is arranged to prevent the charging current of the second energy storage capacitor from being too large, slow charging of the energy storage module is realized, and fluctuation influence on normal electric voltage is reduced.

In a possible implementation manner of the first aspect, the first resistor is a high-power resistor, and a resistance value of the first resistor is related to an output voltage value of the constant power supply and a capacitance value of the second energy storage capacitor. Through setting up first resistance for high-power resistance, can effectively realize the current-limiting of electric current, avoid the electric current too big.

In a possible implementation manner of the first aspect, the first energy storage module further includes: and the anode of the second diode is connected with the first end of the second energy storage capacitor, and the cathode of the second diode is connected with the first electric unit. The second diode can be disconnected when the normal power supply supplies power normally, and the energy storage module is used for supplying power to the first electric unit when the normal power supply fails.

In a possible implementation manner of the first aspect, the second diode is a low-drop diode. By arranging the low-voltage drop diode, the voltage difference between the output voltage of the energy storage module and the voltage received by the first electric unit can be reduced, and the voltage received by the first electric unit is prevented from being too low.

In a possible implementation of the first aspect, the constant electrical power source comprises a storage battery and the first electrical unit comprises a battery management unit.

In a second aspect, embodiments of the present utility model provide a vehicle comprising a constant electrical power source and a protection circuit as in any of the embodiments of the first aspect.

Compared with the prior art, the protection circuit and the vehicle provided by the embodiment of the utility model can limit unidirectional current flowing in the current direction by using the current limiting module. When a current loop between the constant power supply and the first power unit is in disconnection abnormality, the first energy storage module can release stored electric quantity to supply power for the first power unit. The current limiting module can limit the charge released by the first energy storage module to flow to only the first electric unit. The first energy storage module is limited to supply power for the first power unit only, and does not supply power for the second power unit, so that the first power unit can continue to operate after the circuit breaking abnormality occurs.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments of the present utility model will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.

Fig. 1 is a schematic block diagram of a protection circuit according to an embodiment of the present utility model;

fig. 2 is a schematic block diagram of a protection circuit according to another embodiment of the present utility model;

fig. 3 is a schematic circuit diagram of a protection circuit according to an embodiment of the present utility model;

fig. 4 is a schematic circuit diagram of a protection circuit according to another embodiment of the present utility model;

fig. 5 is a schematic circuit diagram of a protection circuit according to another embodiment of the present utility model;

fig. 6 is a schematic circuit diagram of a protection circuit according to still another embodiment of the present utility model;

fig. 7 is a schematic circuit diagram of a protection circuit according to still another embodiment of the present utility model.

In the accompanying drawings:

10. the first electric unit, 20, current limiting module; 30. a first energy storage module; 40. the second electricity utilization unit; 50. a second energy storage module; 60. a constant electric power supply; d1, a first diode; d2, a second diode; MOS1, a first MOS tube; c1, a first energy storage capacitor; c2, a second energy storage capacitor; r1, a first resistor.

Detailed Description

Features and exemplary embodiments of various aspects of the present utility model will be described in detail below, and in order to make the objects, technical solutions and advantages of the present utility model more apparent, the present utility model will be described in further detail below with reference to the accompanying drawings and the detailed embodiments. It should be understood that the particular embodiments described herein are meant to be illustrative of the utility model only and not limiting. It will be apparent to one skilled in the art that the present utility model may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the utility model by showing examples of the utility model.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element.

It should be noted that, without conflict, the embodiments of the present utility model and features of the embodiments may be combined with each other. The embodiments will be described in detail below with reference to the accompanying drawings.

In the related art, in order to realize temporary power supply when a short-term disconnection abnormality occurs in a current loop between a power supply and a power utilization unit, an energy storage capacitor is generally arranged as a standby power supply, and when the power supply is powered down or the current loop is abnormal, the power supply can be continuously supplied to the power utilization unit for a period of time so as to wait for fault removal or ensure that the power utilization unit is powered down safely.

However, the power supply is usually used for supplying power to a plurality of power utilization units, when the power supply fails or a current loop is abnormal, each power utilization unit keeps a mutually communicated state, and the standby power supply not only can supply power to the corresponding power utilization unit, but also can supply power to other communicated power utilization units, so that the power utilization unit provided with the standby power supply cannot continuously maintain a normal running state.

In order to solve the technical problems, the embodiment of the utility model provides a protection circuit and a vehicle. The protection circuit provided by the embodiment of the utility model is first described below.

Fig. 1 shows a schematic diagram of a protection circuit according to an embodiment of the present utility model. The protection circuit comprises a first power unit 10, a current limiting module 20 and a first energy storage module 30.

The first end of the current limiting module 20 is connected to the constant power supply 60, and the second end of the current limiting module 20 is connected to the first electric unit 10. The current limiting module 20 is capable of limiting the direction of current flow to be unidirectional from the first end to the second end.

The constant electric power source 60 is capable of providing a constant electric voltage. The first electric unit 10 may receive the constant electric voltage provided by the constant electric power source 60 and perform voltage conversion on the constant electric voltage to generate an appropriate power supply voltage. It will be appreciated that the first power unit 10 may include a voltage adjustment module and a plurality of power utilization modules, and the power supply voltages required by the respective power utilization modules may be the same or different, which is not limited herein. The first power unit 10 may generate a power supply voltage required by each power module through the voltage adjustment module after receiving the constant power voltage, and provide each power module respectively. The voltage regulation module may be a DC-DC (Direct Current-Direct Current) conversion module, or may be an LDO (low dropout regulator, low dropout linear regulator) or other functional modules capable of implementing voltage conversion.

The constant power supply 60 may supply power to the first power unit 10. As shown in fig. 2, the constant power supply 60 may supply power to at least one second power consumption unit 40 in addition to the first power consumption unit 10. Each second power usage unit 40 is connected to a first end of the current limiting module 20. That is, the first power unit 10 is connected to the constant power supply 60 through the current limiting module 20, and the other second power units 40 are directly connected to the constant power supply 60.

The first energy storage module 30 is connected between the current limiting module 20 and the first electrical unit 10. The first energy storage module 30 is able to assist in supplying power to the first power unit 10.

As an alternative embodiment, the auxiliary power supply manner of the first energy storage module 30 may be to perform energy storage charging during normal power supply of the constant power supply 60, and continue to supply power to the first electric unit 10 by releasing the electric charge during a period when a circuit breaking abnormality occurs in a current loop between the constant power supply 60 and the first electric unit 10. The circuit between the constant power supply 60 and the first power unit 10 may have a disconnection abnormality, which may be a power failure abnormality of the constant power supply 60, or a disconnection or other disconnection abnormality of a connection line between the constant power supply 60 and the first power unit 10.

The first energy storage module 30 is connected to the second end of the current limiting module 20, and the current limiting module 20 can limit the current direction to be unidirectional from the first end to the second end, so that the current limiting module 20 can perform reverse current limiting when the first energy storage module 30 releases charges, and charge leakage of the first energy storage module 30 is avoided.

The charge drain of the first energy storage module 30 may be the drain of charge to ground or may be dissipated through other devices. For example, the charge stored by the first energy storage module 30 may flow into the second power usage unit 40 for dissipation before the current limiting module 20 is not provided. In the above embodiment of the present utility model, when the constant power supply 60 cannot supply power to the first power unit 10, the first energy storage module 30 can continuously supply power to the first power unit 10, and the second power unit 40 is connected to the first end of the current limiting module 20, and the current limiting module 20 is configured to prevent the charges released by the first energy storage module 30 from flowing into the other second power units 40 in a reverse direction, that is, the current limiting module 20 can play a role of avoiding the first energy storage module 30 from supplying power to the second power unit 40 or avoiding the charges stored by the first energy storage module 30 from leaking to the ground, so that the first energy storage module 30 only supplies power to the first power unit 10.

The electric quantity that the first energy storage module 30 can store is very limited, if the first energy storage module 30 also leaks to the ground or supplies power to other second power utilization units 40 when supplying power to the first power utilization unit 10, the power supply duration of the first energy storage module 30 will be greatly shortened, so that the first power utilization unit 10 cannot maintain normal operation. By arranging the current limiting module 20, the electric quantity stored by the first energy storage module 30 can only supply power to the first electric unit 10, so that after the current loop is broken, the duration of the first electric unit 10 in a normal working state is ensured.

In the present embodiment, by providing the current limiting module 20 between the constant electric power source 60 and the first electric unit 10, the current limiting module 20 can be used to limit the current direction to the unidirectional flow of the constant electric power source 60 to the first electric unit 10. The constant power supply 60 is capable of supplying power to the first power unit 10 and charging the first energy storage module 30. When a circuit breaking abnormality occurs in the current loop between the constant power supply 60 and the first electric unit 10, the first energy storage module 30 can release the stored electric quantity to supply power to the first electric unit 10. The current limiting module 20 is capable of limiting the charge released by the first energy storage module 30 to flow only to the first electrical unit 10. That is, the current limiting module 20 can limit the first energy storage module 30 to only supply power to the first electric unit 10, without discharging to the ground or supplying power to the second electric unit 40, so as to ensure the duration that the first electric unit 10 can continue to operate after the disconnection abnormality occurs.

The first energy storage module 30 is capable of supplying power to the first power unit 10 during a period when a current loop is abnormal in disconnection. If the time interval of the current loop with the abnormal open circuit is shorter, the first energy storage module 30 can supply power to the first electric unit 10 until the current loop returns to normal. If the time interval of the current loop with the abnormal open circuit is longer, the first energy storage module 30 can supply power to the first electric unit 10 for a period of time, so that the first electric unit 10 can safely power down after storing the related data.

Referring to fig. 3, in some embodiments, the current limiting module 20 may include a first diode D1.

The positive electrode of the first diode D1 is connected to the constant power supply 60, and the negative electrode of the first diode D1 is connected to the first electric unit 10.

When the constant voltage is output by the constant power supply 60, the current direction is from the positive electrode to the negative electrode of the first diode D1, and at this time, the first power unit 10 can receive the constant voltage output by the constant power supply 60 and maintain normal operation.

The first energy storage module 30 can discharge the stored power when the normal power 60 is powered down. Because the first energy storage module 30 is connected with the cathode of the first diode D1, the second electricity consumption unit 40 is connected with the anode of the first diode D1, and under the current limiting effect of the first diode D1, the electric charge released by the first energy storage module 30 does not flow into the second electricity consumption unit 40 through the first diode D1, i.e. the first energy storage module 30 does not supply power to the second electricity consumption unit 40, but only supplies power to the first electricity unit 10, thereby ensuring that the first electricity unit 10 continues to maintain the running time.

Referring to fig. 4, in some embodiments, the current limiting module 20 may include a first MOS transistor MOS1.

The first MOS transistor MOS1 can be connected between the constant power supply 60 and the first electric unit 10, the first MOS transistor MOS1 comprises a body diode, the anode of the body diode is connected with the constant power supply 60, and the cathode of the body diode is connected with the first electric unit 10; the control end of the first MOS tube MOS1 is connected with the first signal end.

The first signal end can provide a first signal for driving the first MOS tube MOS1 to keep a cut-off state, and the first MOS tube MOS1 keeps a cut-off state under the first signal. When the constant electric power supply 60 outputs a constant electric voltage, the constant electric power supply 60 can supply power to the first electric unit 10 through the body diode; in a period of time when the current loop between the constant power supply 60 and the first power unit 10 is broken, the body diode can limit the reverse flow of the charge into the second power unit 40 when the first energy storage module 30 releases the charge. That is, the body diode can restrict the first energy storage module 30 to supply only the first power unit 10 and not the second power unit 40 without affecting the normal power supply 60 to supply power to the first power unit 10.

It should be noted that, the model parameters of the first diode D1 and the body diode may be determined according to the output voltage of the constant power supply 60 and the power of the first power unit 10.

Referring to fig. 5, in some embodiments, the first energy storage module 30 may include at least one first energy storage capacitor C1.

The first energy storage capacitors C1 are connected in parallel, a first end of each first energy storage capacitor C1 is connected between a second end of the current limiting module 20 and the first electric unit 10, and a second end of each first energy storage capacitor C1 is grounded.

When the constant electric power supply 60 outputs the constant electric voltage, each of the first storage capacitors C1 can be charged at the constant electric voltage. When the current loop between the constant power supply 60 and the first electric unit 10 is broken, each first energy storage capacitor C1 can release electric charge to the first electric unit 10 and continue to supply power to the first electric unit 10, so that the first electric unit 10 continues to maintain operation.

Referring to fig. 6, in some embodiments, the first energy storage module 30 may include a first resistor R1 and at least one second energy storage capacitor C2.

The first end of the first resistor R1 is connected to the second end of the current limiting module 20, the second energy storage capacitors C2 are connected in parallel, the first end of each second energy storage capacitor C2 is connected to the second end of the first resistor R1, and the second end of each second energy storage capacitor C2 is grounded.

When the constant power supply 60 outputs the constant power voltage, the first resistor R1 can perform a current limiting function, so that the excessive current flowing into each second energy storage capacitor C2 is avoided, and the slow charging of each second energy storage capacitor C2 is realized. When the charging current of each second energy storage capacitor C2 is too large, the corresponding capacitive load will impact the constant voltage, so that the constant voltage will fluctuate. By providing the first resistor R1 to reduce the charging current, voltage fluctuation generated when the second energy storage capacitor C2 is charged with the constant voltage can be reduced.

In some embodiments, the first resistor R1 may be a high-power resistor, and the resistance value of the first resistor R1 is related to the output voltage value of the constant power source 60 and the capacitance value of the second energy storage capacitor C2. That is, the resistance value of the first resistor R1 may be determined based on the output voltage value of the constant electric power source 60 and the capacitance value of the second energy storage capacitor C2.

The high-power resistor can effectively reduce the current between the constant-voltage power supply 60 and the second energy storage capacitor C2, slow charging of the second energy storage capacitor C2 is realized, and the influence of the second energy storage capacitor C2 on the constant-voltage in the charging process is reduced.

With continued reference to fig. 6, in some embodiments, the first energy storage module 30 may further include a second diode D2.

The anode of the second diode D2 may be connected to the first end of the second storage capacitor C2, and the cathode of the second diode D2 may be connected to the first electric unit 10.

When the constant voltage is normally output by the constant voltage power supply 60, due to the voltage division effect of the first resistor R1, the first end voltage of the first resistor R1 is higher than the second end voltage, and at this time, the first end voltage of the first resistor R1 is the negative voltage of the second diode D2, and the second end voltage of the first resistor R1 is the positive voltage of the second diode D2. Since the negative voltage of the second diode D2 is higher than the positive voltage, the second diode D2 is in a reverse off state.

When the current loop between the constant power supply 60 and the first electric unit 10 is broken, the voltage at the first end of the first resistor R1 suddenly drops, and at this time, the positive voltage of the second diode D2 is higher than the negative voltage, the second diode D2 is turned from the off state to the on state, and each second energy storage capacitor C2 can be communicated with the first electric unit 10 through the second diode D2 to continue to supply power to the first electric unit 10.

In some embodiments, the second diode D2 may be a low-drop diode.

The second diode D2 is configured as a low-voltage drop diode, so that a voltage difference between the output voltage of the second energy storage capacitor C2 and the voltage received by the first electric unit 10 can be reduced, and the voltage received by the first electric unit 10 is prevented from being too low.

In some embodiments, the constant electrical power source 60 may include, but is not limited to, a battery, which may be a lead-acid battery, a lithium-ion battery, or other battery capable of providing a DC low voltage. The first power unit 10 may include, but is not limited to, a BMU (Battery Management Unit ) that may be provided with a dc voltage by a battery to power the BMU. The BMU is capable of monitoring and managing batteries, which may include, but are not limited to, storage batteries, power cells, or other types of batteries. The BMU can perform voltage monitoring, current detection, temperature monitoring, capacity monitoring, insulation monitoring, relay state monitoring and the like on the battery. And realizing charge and discharge control of the battery according to the monitoring information.

The battery may also power other second power units 40, and other second power units 40 may include, but are not limited to, VCUs (Vehicle control unit, vehicle controllers), BPS (Barometric Pressure Sensor ), central control display card, or other powered devices.

The constant power supply 60 may simultaneously supply power to one or more of the first power unit 10 and the second power unit 40 described above. When the normal power supply 60 fails, in order to avoid the first energy storage module 30 supplying power to the other second power utilization units 40, the current limiting module 20 may be configured to limit the discharging direction of the first energy storage module 30, so that the first energy storage module 30 can only discharge to the first power utilization unit 10, but cannot discharge to the second power utilization unit 40.

It should be noted that, as shown in fig. 7, in the protection circuit, the first energy storage module 30 and the first electric unit 10 may be integrated on the same circuit board, and the first energy storage module 30 may only supply power to the first electric unit 10. For other second power consumption units 40, a second energy storage module 50 may be disposed between the constant power supply 60 and the current limiting module 20, when the constant power supply 60 fails, the first energy storage module 30 between the current limiting module 20 and the first power consumption unit 10 only supplies power to the first power consumption unit 10, and the second energy storage module 50 disposed between the constant power supply 60 and the current limiting module 20 can simultaneously supply power to the first power consumption unit 10 and other second power consumption units 40.

Based on the same inventive concept, the utility model also provides a vehicle comprising a constant electric power source and the protection circuit in any of the above embodiments. It can be appreciated that the vehicle has the beneficial effects of the protection circuit provided by the embodiments of the present utility model, and specific description of the protection circuit with reference to the above embodiments may be omitted herein.

In some embodiments, the constant electrical power source of the vehicle may include a lead-acid battery, a lithium ion battery, or other type of battery.

It should be noted that, without conflict, the embodiments of the present utility model and features of the embodiments may be combined with each other.

The functional blocks shown in the above-described structural block diagrams may be implemented in hardware, software, firmware, or a combination thereof. When implemented in hardware, it may be, for example, an electronic circuit, an Application Specific Integrated Circuit (ASIC), suitable firmware, a plug-in, a function card, or the like. When implemented in software, the elements of the utility model are the programs or code segments used to perform the required tasks. The program or code segments may be stored in a machine readable medium or transmitted over a transmission medium or a communication link by a first data signal carried in a carrier wave. A "machine-readable medium" may include any medium that can store or transfer information. Examples of machine-readable media include electronic circuitry, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio Frequency (RF) links, and the like. The code segments may be downloaded via computer networks such as the internet, intranets, etc.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

The principles and embodiments of the present utility model have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the method of the present utility model and its core ideas. The foregoing is merely a preferred embodiment of the utility model, and it should be noted that, due to the limited text expressions, there is objectively no limit to the specific structure, and that, for a person skilled in the art, modifications, adaptations or variations may be made without departing from the principles of the present utility model, and the above technical features may be combined in any suitable manner; such modifications, variations and combinations, or direct application of the concepts and aspects of the utility model in other applications without modification, are contemplated as falling within the scope of the utility model.

Claims

1. A protection circuit, comprising:

a first electrical unit;

the first end of the current limiting module is connected with a constant electric power supply, and the second end of the current limiting module is connected with the first electric unit; the current limiting module is used for limiting the current direction to be unidirectional from the first end to the second end; the constant power supply is used for supplying power to the first electric unit;

the first energy storage module is connected between the current limiting module and the first electric unit and is used for supplying power to the first electric unit in an auxiliary mode.

2. The protection circuit of claim 1, wherein the current limiting module comprises:

the positive electrode of the first diode is connected with a constant electric power supply, and the negative electrode of the first diode is connected with the first electric unit.

3. The protection circuit of claim 1, wherein the current limiting module comprises:

the first MOS tube is connected between the constant electric power supply and the first electric unit and comprises a body diode, the positive electrode of the body diode is connected with the constant electric power supply, and the negative electrode of the body diode is connected with the first electric unit.

4. A protection circuit according to any one of claims 1-3, wherein the first energy storage module comprises:

the first end of the first energy storage capacitor is connected between the second end of the current limiting module and the first electric unit, and the second end of the first energy storage capacitor is grounded.

5. A protection circuit according to any one of claims 1-3, wherein the first energy storage module comprises:

the first end of the first resistor is connected with the second end of the current limiting module;

and the first end of the second energy storage capacitor is connected with the second end of the first resistor, and the second end of the second energy storage capacitor is grounded.

6. The protection circuit of claim 5, wherein the first resistor is a high-power resistor, and wherein a resistance value of the first resistor is related to an output voltage value of the constant power supply and a capacitance value of the second energy storage capacitor.

7. The protection circuit of claim 5, wherein the first energy storage module further comprises:

and the anode of the second diode is connected with the first end of the second energy storage capacitor, and the cathode of the second diode is connected with the first electric unit.

8. The protection circuit of claim 7, wherein the second diode is a low drop diode.

9. A protection circuit according to any one of claims 1-3, wherein the constant electrical power source comprises a storage battery and the first electrical unit comprises a battery management unit.

10. A vehicle comprising a constant electrical power source and a protection circuit as claimed in any one of claims 1 to 9.