Charging protection circuit, method and device

Abstract

The present invention discloses a charging protection circuit, method and device. The charging protection circuit includes a first protection module and a second protection module; the input end of the first protection module is connected to the live wire, and the output end is connected to the input end of the second protection module; the output end of the second protection module is connected to the charging module of the vehicle; the first protection module switches the corresponding switch state according to the temperature range of the charging temperature; when the charging voltage and / or charging current is less than the first preset value, the second protection module determines whether the vehicle is in a charging state according to the charging signal sent by the charging module, and when the vehicle is in a charging state, detects the switch state of the first protection module, and sends a stop charging signal to the charging module when the switch state of the first protection module is disconnected. Among them, through the design of the first and second protection modules, when the vehicle is in a charging state and the charging temperature is too high, the power supply can be disconnected and charging can be stopped, reducing the risk caused by overheating of charging.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle charging, and in particular to a charging protection circuit, method and device. Background Art

[0002] As global energy shortages, environmental pollution and driving safety challenges become increasingly severe, new energy vehicles have been widely favored by consumers because they can use electricity as a power source, save fuel energy, reduce exhaust emissions, have high efficiency and low noise.

[0003] When charging new energy vehicles, it is usually necessary to connect the power plug to a household socket for charging. However, since household sockets are prone to loosening and other poor contact, overheating may occur during the charging process, and in severe cases, a fire may occur, threatening the life and property safety of the owner, and the charging risk is relatively high. Summary of the invention

[0004] The main purpose of the present invention is to provide a charging protection circuit, method and device, aiming to solve the technical problem in the prior art that the charging risk of new energy vehicles is relatively high due to overheating when charging.

[0005] To achieve the above object, the present invention provides a charging protection circuit, the circuit comprising:

[0006] A first protection module and a second protection module; the input end of the first protection module is connected to the live wire, the output end of the first protection module is connected to the input end of the second protection module, and the output end of the second protection module is connected to the charging module of the vehicle; wherein,

[0007] The first protection module is used to detect the charging temperature and switch the corresponding switch state according to the temperature range of the charging temperature;

[0008] The second protection module is used to detect the charging voltage and / or the charging current, and when the charging voltage and / or the charging current is less than a first preset value, determine whether the vehicle is in a charging state according to the charging signal sent by the charging module, and when the vehicle is in a charging state, detect the switch state of the first protection module, and send a stop charging signal to the charging module when the switch state of the first protection module is disconnected.

[0009] Preferably, the first protection module includes a temperature switch, the input end of the temperature switch is connected to the live wire, and the output end of the temperature switch is connected to the second protection module; the temperature switch is used to detect the charging temperature, and is closed when the charging temperature is not greater than a second preset value, and is opened when the charging temperature is greater than the second preset value.

[0010] Preferably, the second protection module includes a switch unit, a voltage detection unit and a control unit; the switch unit is arranged on the live wire and the neutral wire, the first end of the switch unit is connected to the output end of the first protection module, the second end of the switch unit is connected to the first input end of the voltage detection unit, and the third end of the switch unit is connected to the control end of the control unit; the second input end of the voltage detection unit is connected to the neutral wire, and the output end of the voltage detection unit is connected to the first input end of the control unit; the output end of the control unit is connected to the charging module; wherein,

[0011] The voltage detection unit is used to detect the charging voltage and send the charging voltage to the control unit;

[0012] The control unit is used to determine whether the vehicle is in a charging state according to a charging signal sent by the charging module when the charging voltage is less than a first preset value, and to detect the switching state of the switch unit when the vehicle is in a charging state. When the switching state of the switch unit is closed, it is determined that the switching state of the first protection module is open, and a stop charging signal is sent to the charging module.

[0013] Preferably, the switch unit includes a first relay and a second relay; the first relay is arranged on the live wire, the second relay is arranged on the neutral wire, the first contact of the first relay is connected to the output end of the first protection module as the first end of the switch unit, the second contact of the first relay is connected to the first input end of the voltage detection unit as the second end of the switch unit, and the coil of the first relay and the coil of the second relay are connected to the control end of the control unit as the third end of the switch unit.

[0014] Preferably, the second protection module also includes a sampling unit and a current detection unit; the input end of the sampling unit is connected to the second end of the switch unit, the output end of the sampling unit is connected to the input end of the current detection unit, and the output end of the current detection unit is connected to the second input end of the control unit.

[0015] Preferably, the second protection module also includes a power supply unit, a first input end of the power supply unit is respectively connected to the live wire and the input end of the first protection module, a second input end of the power supply unit is respectively connected to the neutral wire and the fourth end of the switch unit, and an output end of the power supply unit is connected to the power supply end of the control unit.

[0016] The present invention also provides a charging protection method, which comprises the following steps:

[0017] Detecting a charging voltage and / or a charging current, and when the charging voltage and / or the charging current are less than a first preset value, obtaining a charging instruction and determining whether the vehicle is in a charging state;

[0018] When the vehicle is in a charging state, detecting a first switch state;

[0019] When the first switch state is off, a charging stop instruction is output.

[0020] Preferably, the step of detecting the first switch state comprises:

[0021] detecting a second switch state;

[0022] When the second switch state is closed, it is determined that the first switch state is open.

[0023] Preferably, after the step of outputting the charging stop instruction, the method further comprises:

[0024] Detect whether the power plug is pulled out and inserted;

[0025] When the pulling out and inserting actions occur, the output of the charging stop instruction is stopped.

[0026] The present invention further provides a charging protection device, which includes the charging protection circuit as described above, or applies the charging protection method as described above.

[0027] The present invention sets a first protection module and a second protection module in a charging protection circuit; the input end of the first protection module is connected to the live wire, and the output end is connected to the input end of the second protection module; the output end of the second protection module is connected to the charging module of the vehicle; the first protection module switches the corresponding switch state according to the temperature range of the charging temperature; when the charging voltage and / or charging current is less than the first preset value, the second protection module determines whether the vehicle is in a charging state according to the charging signal sent by the charging module, and when the vehicle is in a charging state, detects the switch state of the first protection module, and sends a stop charging signal to the charging module when the switch state of the first protection module is disconnected. Among them, through the design of the first and second protection modules, when the vehicle is in a charging state and the charging temperature is too high, the power supply can be disconnected and charging can be stopped, reducing the risk caused by overheating of charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0029] Figure 1 is a functional module diagram of an embodiment of a charging protection circuit of the present invention;

[0030] Figure 2 yes Figure 1 An optional structural diagram of a charging protection circuit;

[0031] Figure 3 yes Figure 1 Charging protection circuit - optional circuit schematic diagram;

[0032] Figure 4 It is a flow chart of an embodiment of a charging protection method of the present invention.

[0033] Description of Figure Numbers:

[0034] Label name Label name 10 The first protection module K1 First relay 20 Second protection module K2 Second relay 30 Charging module 1 Power plug 210 Switching unit 2 Household socket 220 Voltage detection unit 3 Charging control box 230 Control unit 4 Charging gun 240 Sampling unit L FireWire 250 Current sensing unit N Neutral 260 Power supply unit PE Ground S1 Temperature switch

[0035] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0038] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] The invention provides a charging protection circuit.

[0040] Reference Figure 1 In one embodiment, the circuit includes a first protection module 10 and a second protection module 20; the input end of the first protection module 10 is connected to the live wire L, the output end of the first protection module 10 is connected to the input end of the second protection module 20, and the output end of the second protection module 20 is connected to the charging module 30 of the vehicle; wherein, the first protection module 10 is used to detect the charging temperature and switch the corresponding switch state according to the temperature range of the charging temperature; the second protection module 20 is used to detect the charging voltage and / or the charging current, and when the charging voltage and / or the charging current are less than a first preset value, determine whether the vehicle is in a charging state according to the charging signal sent by the charging module 30, and when the vehicle is in a charging state, detect the switch state of the first protection module 10, and when the switch state of the first protection module 10 is disconnected, send a stop charging signal to the charging module 30.

[0041] Please refer to Figure 2 When charging, new energy vehicles usually connect the power plug 1 connected to the charging gun 4 to the household socket 2. However, since the household socket 2 is prone to aging, poor use environment, poor socket contact, etc., it will heat up seriously during charging, resulting in unsafe charging. In this embodiment, the first protection module 10 can be set in the power plug 1, and the second protection module 20 can be set in the charging control box 3. When the power plug 1 is connected to the household socket 2, the first protection module 10 in the power plug 1 will be disconnected when the temperature is too high, and the second protection module 20 in the charging control box 3 implements a protection strategy according to the switch state of the first protection module 10.

[0042] Specifically, the first protection module 10 detects the charging temperature, closes when the charging temperature is not greater than the second preset value, and opens when the charging temperature is greater than the second preset value. The second protection module 20 records the charging voltage and / or charging current in real time. When the charging voltage and / or the charging current are abnormal, it determines whether the vehicle is in a charging state according to the charging signal sent by the charging module 30, and when the vehicle is in a charging state, detects the switch state of the first protection module. When the switch state of the first protection module is disconnected, it can be determined that the vehicle is in a charging state and the charging temperature is too high. At this time, a stop charging signal is sent to the charging module 30 of the vehicle to stop the vehicle from charging, thereby ensuring charging safety.

[0043] This embodiment sets a first protection module and a second protection module in the charging protection circuit; the input end of the first protection module is connected to the live wire, and the output end is connected to the input end of the second protection module; the output end of the second protection module is connected to the charging module of the vehicle; the first protection module switches the corresponding switch state according to the temperature range of the charging temperature; when the charging voltage and / or charging current is less than the first preset value, the second protection module determines whether the vehicle is in the charging state according to the charging signal sent by the charging module, and when the vehicle is in the charging state, detects the switch state of the first protection module, and sends a stop charging signal to the charging module when the switch state of the first protection module is disconnected. Among them, through the design of the first and second protection modules, when the vehicle is in the charging state and the charging temperature is too high, the power supply can be disconnected and charging can be stopped, reducing the risk caused by overheating of charging.

[0044] Please refer to Figure 3 , Figure 3 yes Figure 1 Charging protection circuit - optional circuit schematic diagram.

[0045] In this embodiment, the first protection module 10 includes a temperature switch S1, the input end of the temperature switch S1 is connected to the live wire L, and the output end of the temperature switch S1 is connected to the second protection module 20; the temperature switch S1 is used to detect the charging temperature, and is closed when the charging temperature is not greater than a second preset value, and is opened when the charging temperature is greater than the second preset value.

[0046] In a specific implementation, the temperature switch S1 can be set in the power plug, connected in series to the live wire L, and a normally closed switch is used. When the charging temperature is greater than the second preset value, it will automatically disconnect, and when the charging temperature is not greater than the second preset value, it will remain closed to achieve charging. This embodiment uses the temperature switch S1 to detect the charging temperature instead of the thermistor design, avoiding the time delay caused by the controller collecting and judging the temperature signal and then controlling the switch, making the circuit structure simpler and also improving the circuit's response speed to overheating.

[0047] Further, the second protection module 20 includes a switch unit 210, a voltage detection unit 220 and a control unit 230; the switch unit 210 is arranged on the live wire L and the neutral wire N, the first end of the switch unit 210 is connected to the output end of the first protection module 10, the second end of the switch unit 210 is connected to the first input end of the voltage detection unit 220, and the third end of the switch unit 210 is connected to the control end of the control unit 230; the second input end of the voltage detection unit 220 is connected to the neutral wire N, the output end of the voltage detection unit 220 is connected to the first input end of the control unit 230; the output end of the control unit 230 is connected to the charging module 30 wherein the switch unit 210 is used to receive the switch state signal and send the switch state signal to the control unit 230; the voltage detection unit 220 is used to detect the charging voltage and send the charging voltage to the control unit 230; the control unit 230 is used to determine whether the vehicle is in a charging state according to the charging signal sent by the charging module 30 when the charging voltage is less than a first preset value, and when the vehicle is in a charging state, detect the switch state of the switch unit 210, and when the switch state of the switch unit 210 is closed, determine that the switch state of the first protection module 10 is open, and send a stop charging signal to the charging module 30.

[0048] It should be noted that the charging voltage is less than the first preset value due to two situations. The first situation is that the charging temperature is too high and the first protection module 10 is disconnected; the second situation is that the user actively stops charging by disconnecting the switch unit 210. Obviously, the first situation requires over-temperature protection, but the second situation does not. Therefore, when the control unit 230 detects that the switch state of the switch unit 210 is closed, it means that the user did not actively stop charging, and it can be determined that the abnormal charging voltage is caused by the disconnection of the first protection module 10. At this time, it is necessary to send a stop charging signal to the charging module 30.

[0049] It should be understood that when the charging voltage is not less than the first preset value, it can be determined that the entire circuit is turned on, the charging temperature in the first protection module 10 is not greater than the second preset value, and over-temperature protection is not required.

[0050] Specifically, the switch unit 210 includes a first relay K1 and a second relay K2; the first relay K1 is arranged on the live wire L, the second relay K2 is arranged on the neutral wire N, the first contact of the first relay K1 is connected to the output end of the first protection module 10 as the first end of the switch unit 210, the second contact of the first relay K1 is connected to the first input end of the voltage detection unit 220 as the second end of the switch unit 210, and the coil of the first relay K1 and the coil of the second relay K2 are connected to the control end of the control unit 230 as the third end of the switch unit 210.

[0051] It is easy to understand that the control unit 230 can control the output of voltage by controlling the opening and closing of the relay. When the relay is disconnected, the connection between the first protection module 10 and the charging module 30 is disconnected, and the charging power supply is cut off, further ensuring charging safety.

[0052] Of course, when the vehicle stops charging, the temperature detected by the temperature switch S1 will be lower than the first preset value, and the temperature switch S1 will be closed. At this time, the control unit 230 is set to not allow restarting charging to prevent the temperature switch S1 from overheating again. The control unit 230 allows recharging only when it detects that the power plug 1 has been unplugged and reinserted into the household socket 2. In this way, the temperature switch S1 can be prevented from being damaged by repeated actions and causing secondary accidents, and the relay can also be prevented from being repeatedly actuated, thereby extending the service life of the product.

[0053] Furthermore, the second protection module 20 also includes a sampling unit 240 and a current detection unit 250; the input end of the sampling unit 240 is connected to the second end of the switch unit 210, the output end of the sampling unit 240 is connected to the input end of the current detection unit 250, and the output end of the current detection unit 250 is connected to the second input end of the control unit 230.

[0054] It should be understood that the sampling unit 240 is used to sample the charging current and send the charging current to the control unit 230. As an embodiment, the sampling unit 240 can use a Hall sensor, and by connecting the Hall sensor to the live wire L, the live wire L current (i.e., charging current) can be sampled.

[0055] In a specific implementation, after receiving the charging current, when the charging current is less than a first preset value, the control unit 230 determines whether the vehicle is in a charging state according to the charging signal sent by the charging module 30, and when the vehicle is in a charging state, detects the switching state of the switch unit 210. When the switching state of the switch unit 210 is closed, it determines that the switching state of the first protection module 10 is open, and sends a stop charging signal to the charging module 30.

[0056] It should be noted that, in a specific implementation, the control unit 230 can determine whether to perform over-temperature protection by simultaneously detecting whether the charging current and the charging voltage are less than the first preset value, or can only detect either the charging current or the charging voltage. By detecting the charging voltage and the charging current, all charging information can be recorded, including information on charging over-temperature and when the first protection module 10 is disconnected.

[0057] Furthermore, the second protection module 20 also includes a power supply unit 260, a first input end of the power supply unit 260 is respectively connected to the live wire L and the input end of the first protection module 10, a second input end of the power supply unit 260 is respectively connected to the neutral wire N and the fourth end of the switch unit 210, and an output end of the power supply unit 260 is connected to the power supply end of the control unit 230.

[0058] It should be noted that, in this embodiment, the first input end of the power supply unit 260 is arranged before the first protection module 10. Even if the first protection module 10 is disconnected due to overtemperature, the power supply unit 260 can also normally supply power to the second protection module 20 in the charging control box, continue to control the switch unit 210 and send signals to the charging module 30.

[0059] This embodiment designs the first protection module as a temperature switch, which can respond quickly to charging overtemperature. Through the design of the second protection module, the charging current and / or charging voltage can be continuously recorded normally when the first protection module is disconnected, and the relay can be disconnected when the charging overtemperature occurs, so as to promptly inform the charging module to stop charging, thereby effectively avoiding safety accidents caused by charging overtemperature.

[0060] Please refer to Figure 1 , Figure 3 and Figure 4 , Figure 4 The present invention is based on Figure 1 A flowchart of an embodiment of the proposed charging protection method.

[0061] In this embodiment, the charging protection method includes the following steps:

[0062] S10: Detecting a charging voltage and / or a charging current, and when the charging voltage and / or the charging current are less than a first preset value, obtaining a charging instruction and determining whether the vehicle is in a charging state;

[0063] It should be understood that the first protection module 10 can be a temperature switch S1, which is arranged in the power plug 1, and its switch state includes closed and open. When the temperature switch S1 detects that the charging temperature is greater than the second preset value, it is opened, otherwise it is closed. The second protection module 20 can be arranged in the charging control box 3, and detect the charging voltage and / or charging current in real time. When the charging voltage and / or charging current is less than the first preset value, the charging instruction sent by the charging module 30 is obtained, and it is determined whether the vehicle is in a charging state.

[0064] S20: When the vehicle is in a charging state, detecting a first switch state;

[0065] It is easy to understand that the charging voltage and / or charging current being less than the first preset value is caused by two situations. The first situation is that the charging temperature is too high and the first protection module 10 is disconnected; the second situation is that the user actively stops charging by disconnecting the switch unit 210. Obviously, the first situation requires over-temperature protection, but the second situation does not. The first switch state refers to the switch state of the first protection module 10. When the second switch state (i.e., the switch state of the switch unit 210) is closed, it means that the user did not actively stop charging, then it can be determined that the abnormal charging voltage is caused by the disconnection of the first protection module 10.

[0066] S30: When the first switch state is disconnected, output a charging stop instruction.

[0067] In a specific implementation, since the temperature switch S1 is used in the first protection module 10, the temperature switch S1 will be closed after charging stops. In order to prevent the device from restarting charging, it is necessary to detect whether there is an action of pulling out and inserting the power plug 1; when the pulling out and inserting action is detected, the connection between the first protection module 10 and the charging module 30 is controlled to be turned on, and a charging instruction is sent to the charging module 30 to charge the charging module 30. When the pulling out and inserting action is not detected, the connection between the first protection module 10 and the charging module 30 is still controlled to be disconnected, and a stop charging instruction is sent to the charging module 30 to avoid overheating again, and the temperature switch S1 is repeatedly operated to cause damage, which may cause a secondary accident.

[0068] This embodiment detects the charging voltage and / or charging current, and when the charging voltage and / or charging current is less than a first preset value, obtains a charging instruction and determines whether the vehicle is in a charging state; when the vehicle is in a charging state, detects a first switch state; when the first switch state is disconnected, outputs a stop charging instruction to stop the charging module from charging, thereby reducing the risk caused by overheating during charging.

[0069] The present invention further provides a charging protection device, which includes the charging protection circuit as described above, or applies the charging protection method as described above. It is easy to understand that the charging protection device at least has the beneficial effects brought by the above embodiments.

[0070] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A charging protection circuit, characterized in that: It includes a first protection module and a second protection module; the input end of the first protection module is connected to the live wire, the output end of the first protection module is connected to the input end of the second protection module, and the output end of the second protection module is connected to the charging module of the vehicle; wherein, The first protection module is used to detect the charging temperature and switch the corresponding switch state according to the temperature range of the charging temperature; The second protection module is used to detect the charging voltage and / or the charging current, and when the charging voltage and / or the charging current is less than a first preset value, determine whether the vehicle is in a charging state according to the charging signal sent by the charging module, and when the vehicle is in a charging state, detect the switch state of the first protection module, and send a stop charging signal to the charging module when the switch state of the first protection module is disconnected; The second protection module includes a switch unit, a voltage detection unit and a control unit; the switch unit is arranged on the live wire and the neutral wire, the first end of the switch unit is connected to the output end of the first protection module, the second end of the switch unit is connected to the first input end of the voltage detection unit, and the third end of the switch unit is connected to the control end of the control unit; the second input end of the voltage detection unit is connected to the neutral wire, and the output end of the voltage detection unit is connected to the first input end of the control unit; the output end of the control unit is connected to the charging module; wherein, The voltage detection unit is used to detect the charging voltage and send the charging voltage to the control unit; The control unit is used to determine whether the vehicle is in a charging state according to a charging signal sent by the charging module when the charging voltage is less than a first preset value, and to detect the switch state of the switch unit when the vehicle is in a charging state, and to determine that the switch state of the first protection module is open when the switch state of the switch unit is closed, and to send a stop charging signal to the charging module; The control unit is used to determine that the charging protection circuit is turned on and that the first protection module does not need over-temperature protection when the charging voltage is greater than or equal to a first preset value.

2. The charging protection circuit according to claim 1, characterized in that: The first protection module includes a temperature switch, the input end of the temperature switch is connected to the live wire, and the output end of the temperature switch is connected to the second protection module; the temperature switch is used to detect the charging temperature, and is closed when the charging temperature is not greater than a second preset value, and is opened when the charging temperature is greater than the second preset value.

3. The charging protection circuit according to claim 1, characterized in that: The switch unit includes a first relay and a second relay; the first relay is arranged on the live wire, the second relay is arranged on the neutral wire, the first contact of the first relay is connected to the output end of the first protection module as the first end of the switch unit, the second contact of the first relay is connected to the first input end of the voltage detection unit as the second end of the switch unit, the coil of the first relay and the coil of the second relay are connected to the control end of the control unit as the third end of the switch unit; wherein, The control unit is used to control the output of voltage by controlling the opening and closing of the first relay and the second relay.

4. The charging protection circuit according to claim 1, characterized in that: The second protection module further includes a sampling unit and a current detection unit; the input end of the sampling unit is connected to the second end of the switch unit, the output end of the sampling unit is connected to the input end of the current detection unit, and the output end of the current detection unit is connected to the second input end of the control unit; wherein, The sampling unit is used to sample the charging current and send the charging current to the control unit.

5. The charging protection circuit according to claim 1, characterized in that: The second protection module further includes a power supply unit, a first input end of the power supply unit is respectively connected to the live wire and the input end of the first protection module, a second input end of the power supply unit is respectively connected to the neutral wire and the fourth end of the switch unit, an output end of the power supply unit is connected to the power supply end of the control unit, and the first input end is arranged before the first protection module; wherein, The power supply unit is used to supply power to the second protection module when the switch state of the first protection module is disconnected.

6. A charging protection method, characterized in that: The charging protection method is applied to a second protection module in a charging protection circuit, wherein the charging protection circuit further comprises a first protection module, wherein an input end of the first protection module is connected to a live wire, an output end of the first protection module is connected to an input end of the second protection module, and an output end of the second protection module is connected to a charging module of a vehicle, wherein the first protection module is used to detect a charging temperature and switch a corresponding switch state according to a temperature range of the charging temperature; The charging protection method comprises the following steps: Detecting a charging voltage and / or a charging current, and when the charging voltage and / or the charging current are less than a first preset value, obtaining a charging instruction and determining whether the vehicle is in a charging state; When the vehicle is in a charging state, detecting a first switch state, wherein the first switch state is a switch state of the first protection module; When the first switch state is disconnected, outputting a charging stop instruction; The second protection module includes a switch unit, a voltage detection unit and a control unit; the switch unit is arranged on the live wire and the neutral wire, the first end of the switch unit is connected to the output end of the first protection module, the second end of the switch unit is connected to the first input end of the voltage detection unit, and the third end of the switch unit is connected to the control end of the control unit; the second input end of the voltage detection unit is connected to the neutral wire, and the output end of the voltage detection unit is connected to the first input end of the control unit; the output end of the control unit is connected to the charging module; wherein, The voltage detection unit is used to detect the charging voltage and send the charging voltage to the control unit; The control unit is used to determine whether the vehicle is in a charging state according to a charging signal sent by the charging module when the charging voltage is less than a first preset value, and to detect the switch state of the switch unit when the vehicle is in a charging state, and to determine that the switch state of the first protection module is open when the switch state of the switch unit is closed, and to send a stop charging signal to the charging module; The control unit is used to determine that the charging protection circuit is turned on and that the first protection module does not need over-temperature protection when the charging voltage is greater than or equal to a first preset value.

7. The charging protection method according to claim 6, characterized in that: The step of detecting the first switch state comprises: detecting a second switch state; When the second switch state is closed, it is determined that the first switch state is open.

8. The charging protection method according to claim 7, characterized in that: After the step of outputting the charging stop instruction, the method further includes: Detect whether the power plug is pulled out and inserted; When the pulling out and inserting actions occur, the output of the charging stop instruction is stopped.

9. A charging protection device, characterized in that: The invention comprises a charging protection circuit as claimed in any one of claims 1 to 5 or applies a charging protection method as claimed in any one of claims 6 to 8.

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