CN116533792A - Electric vehicle direct-current charging system, electric vehicle and direct-current charging method - Google Patents

Abstract

The application relates to the technical field of DC charging for electric vehicles, and provides a DC charging system for electric vehicles, an electric vehicle and a DC charging method. The electric vehicle DC charging system includes: a vehicle control module; the first end of the first switch switching module is electrically connected to the communication port of the adapter, and the third end of the second switch switching control module is electrically connected to the vehicle-mounted OBC; the resistance detection module is connected to the The adapter is electrically connected to detect the resistance of the adapter; the first end of the second switch module is electrically connected to the power output end of the adapter, and the second end of the second switch module is electrically connected to the original car battery pack; the first voltage The detection module is electrically connected to the first end of the second switch switching module, and the first voltage detection module is electrically connected to the vehicle control module. According to the electric vehicle DC charging system of the embodiment of the present application, the automatic detection of the adapter is realized, and the AC charging socket can be directly used for low-voltage DC charging of the original vehicle battery pack without using a DC/DC module.

Description

Electric vehicle DC charging system, electric vehicle and DC charging method

technical field

The present application relates to the technical field of DC charging for electric vehicles, in particular to a DC charging system for electric vehicles, an electric vehicle and a DC charging method.

Background technique

In order to meet the needs of different consumers for electric vehicles, automobile manufacturers have successively launched models with different mileage and different prices. Some models only have an AC charging stand and cannot be directly charged with a DC charging device.

In order to enable vehicles with only AC charging bases to have DC charging functions at the same time, there is currently a solution to connect the adapter to the AC charging base, so that the DC charging device can charge the vehicle through the adapter. However, in the vehicle charging system in the related art, the voltage output by the DC charging device must be regulated through the DC/DC module, the solution is relatively complicated, and it is difficult to realize the automatic detection of the adapter.

Contents of the invention

The present application aims to solve at least one of the technical problems existing in the related art. For this reason, this application proposes a DC charging system for electric vehicles, which realizes the automatic detection of the adapter, and based on the detection results of the adapter, controls the vehicle to switch from AC charging to DC charging, and DC/DC may not be used in some cases The module directly charges the original car battery pack with low-voltage DC, and the solution is simpler.

The present application also proposes an electric vehicle.

The application also proposes a DC charging method for an electric vehicle.

The DC charging system for an electric vehicle according to an embodiment of the present application is suitable for being connected to an adapter, the adapter is suitable for connecting to a DC charging device, and the DC charging system for an electric vehicle includes:

vehicle control module;

A first switch switching module, the first end of the first switch switching module is electrically connected to the communication port of the adapter, the second end of the first switch switching module is electrically connected to the vehicle control module, and the first switch switching module is electrically connected to the vehicle control module. The third end of the second switch switching control module is electrically connected to the vehicle-mounted OBC;

a resistance detection module electrically connected to the vehicle control module, the resistance detection module is electrically connected to the adapter to detect the resistance of the adapter;

The second switch switching module, the first end of the second switch switching module is electrically connected to the power output end of the adapter, the second end of the second switch switching module is electrically connected to the original car battery pack, the The third end of the second switch switching module is electrically connected to the vehicle control module;

A voltage conversion module, electrically connected between the fourth terminal of the second switching module and the original vehicle battery pack;

The first voltage detection module is electrically connected to the first end of the second switch switching module, the first voltage detection module is electrically connected to the vehicle control module, and the first voltage detection module is suitable for detecting the direct current The voltage delivered by the charging device to the second switch switching module via the adapter;

The boost module is electrically connected to the vehicle control module, the boost module is electrically connected to the DC charging device, and the boost module is suitable for boosting the initial voltage of the vehicle to a preset voltage and then delivering it to the DC charging equipment.

According to the electric vehicle DC charging system of the embodiment of the present application, when the adapter is connected to the vehicle charging socket, the resistance detection module will detect the resistance of the adapter, and transmit the detection result to the vehicle control module, so that the vehicle control module can judge Whether the current connection with the vehicle charging socket is an adapter. When it is determined that the adapter is connected to the vehicle charging socket, the vehicle control module controls the first end of the first switch switching module to communicate with the second end, so that the communication port of the adapter communicates with the vehicle control module, and the vehicle control module can pass through the adapter. The communication port interacts with the DC charging device.

The vehicle control module obtains the charging voltage of the original vehicle battery pack and the output voltage range of the DC charging equipment, and compares the charging voltage of the original vehicle battery pack with the output voltage range of the DC charging equipment. When the charging voltage of the original car battery pack is within the output voltage range of the DC charging device, the DC charging device is turned on, and the DC charging device outputs a voltage matching the charging voltage of the original car battery pack, and the vehicle control module controls the second switch switching module The first terminal and the second terminal of the battery are connected, and the voltage can be directly transmitted to the original vehicle battery pack through the adapter and the second switch switching module to realize charging of the original vehicle battery pack.

When the charging voltage of the original car battery pack is not within the output voltage range of the DC charging device, the vehicle control module controls the boost module to boost the initial voltage of the vehicle to a preset voltage, and use the preset voltage as a virtual original car battery pack The charging voltage is sent to the DC charging device. Since the preset voltage is within the output voltage range of the DC charging device, the DC charging device can be turned on normally. At this time, the vehicle control module will send a corresponding signal to the DC charging device, so that the DC charging device will The output voltage is adjusted to the charging voltage of the original car battery pack. The voltage output by the DC charging device is sent to the second switching module through the adapter, and the first voltage detection module will perform voltage detection at this time. If the voltage detected by the first voltage detection module is consistent with the charging voltage of the original vehicle battery pack, it means that the DC charging device has successfully adjusted the output voltage to the charging voltage of the original vehicle battery pack, and the vehicle control module controls the second switching module. One end is connected with the second end, so that the voltage can be directly transmitted to the original vehicle battery pack through the adapter and the second switch switching module, so as to realize charging of the original vehicle battery pack. If the voltage detected by the first voltage detection module does not match the charging voltage of the original vehicle battery pack, it means that the DC charging device has not adjusted the output voltage to the charging voltage of the original vehicle battery pack, and the vehicle control module controls the second switch switching module The first terminal and the fourth terminal are connected, so that the voltage output by the DC charging device is transmitted to the voltage conversion module through the adapter and the second switch module, and the voltage conversion module converts the voltage into the charging voltage of the original car battery pack and then transmits it to the The original car battery pack realizes the charging of the original car battery pack. Furthermore, this application realizes the automatic detection of the adapter, and based on the detection result of the adapter, controls the vehicle to switch from AC charging to DC charging, and in some cases can directly perform low-voltage DC charging on the original vehicle battery pack without using the DC/DC module. Charging, the solution is simpler.

According to an embodiment of the present application, the first switching module includes a first switching element, a second switching element, a third switching element, and a fourth switching element, and the first switching element is electrically connected to CC of the adapter. port and the vehicle-mounted OBC, the second switch element is electrically connected to the CC port of the adapter and the vehicle control module, and the third switch element is electrically connected to the CP port of the adapter and the vehicle-mounted OBC, The fourth switch element is electrically connected to the CP port of the adapter and the vehicle control module.

According to an embodiment of the present application, the second switching module includes a fifth switching element, the first end of the fifth switching element is electrically connected to the power output end of the adapter, and the fifth switching element The second end is electrically connected to the original vehicle battery pack, the third end of the fifth switch element is electrically connected to the vehicle control module, and the fourth end of the fifth switch element is electrically connected to the voltage conversion module , the vehicle control module is adapted to control the fifth switch element to switch between a first state and a second state, wherein, in the first state, the fifth switch element is connected to the power output of the adapter terminal and the original vehicle battery pack, and in the second state, the fifth switching element is connected to the power output terminal of the adapter and the voltage conversion module.

According to an embodiment of the present application, the electric vehicle DC charging system includes a third switch switching module, the first end of the third switch switching module is electrically connected to the power output end of the adapter, and the third switch The second end of the switching module is electrically connected to the on-board OBC, the on-board control module is electrically connected to the third switch switching module, and the on-board OBC is electrically connected to the original car battery pack.

According to an embodiment of the present application, the electric vehicle DC charging system includes a second voltage detection module, the second voltage detection module is electrically connected to the first terminal of the third switch switching module, and the second voltage detection module The module is electrically connected to the vehicle control module, and the second voltage detection module is used to detect the magnitude of the voltage sent from the DC charging equipment to the third switch switching module through the adapter.

According to an embodiment of the present application, the electric vehicle DC charging system includes a vehicle-mounted step-down power supply, the input end of the vehicle-mounted step-down power supply is electrically connected to the vehicle-mounted OBC, and the output terminal of the vehicle-mounted step-down power supply is suitable for To be electrically connected to the on-board equipment, the on-board OBC is adapted to transmit electric energy to the on-board step-down power supply, so that the on-board step-down power supply can charge the on-board equipment.

According to an embodiment of the second aspect of the present application, an electric vehicle includes the above-mentioned DC charging system for an electric vehicle.

According to the electric vehicle of the present application, it has the above-mentioned electric vehicle DC charging system, so it has all the technical effects of the above-mentioned electric vehicle DC charging system, which will not be repeated here.

According to an embodiment of the present application, the electric vehicle DC charging system includes a third voltage detection module, the third voltage detection module is electrically connected to the power input end of the adapter, and the power input end of the adapter is connected to the power input end of the adapter. The DC charging device is electrically connected, the third voltage detection module is connected to the vehicle control module, and the third voltage detection module is adapted to detect the voltage delivered to the adapter by the DC charging device.

According to an embodiment of the third aspect of the present application, the DC charging method for an electric vehicle includes:

Obtain the detection data of the resistance detection module, and confirm that the adapter is connected to the vehicle charging socket;

Obtain the charging voltage of the original car battery pack;

Obtain the output voltage of the DC charging device;

If the difference between the charging voltage and the output voltage is within a preset range, then controlling the output voltage to charge the original vehicle battery pack;

If the difference between the charging voltage and the output voltage is not within the preset interval, the output voltage is controlled to be sent to a voltage conversion module, and the voltage conversion module is controlled to convert the output voltage into a preset voltage to the Charge the original car battery pack.

According to an embodiment of the present application, a target vehicle-mounted device is determined, and the target vehicle-mounted device has an electric energy storage function;

controlling the adapter to deliver the voltage of the DC charging device to the vehicle-mounted OBC;

Controlling the on-board OBC to deliver the voltage to the on-board step-down power supply;

Controlling the vehicle step-down power supply to charge the target vehicle equipment.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or related technologies. Obviously, the accompanying drawings in the following description are only For some embodiments of the application, those skilled in the art can also obtain other drawings based on these drawings without creative work.

1 is a schematic diagram of an electric vehicle DC charging system provided in an embodiment of the present application;

Fig. 2 is one of the partial schematic diagrams of the electric vehicle DC charging system provided by the embodiment of the present application;

3 is a schematic diagram of a low-power switching circuit for a vehicle step-down power supply provided in an embodiment of the present application;

4 is a circuit diagram of a low-power switching circuit for a vehicle-mounted step-down power supply provided in an embodiment of the present application;

Fig. 5 is another circuit diagram of the first switch circuit provided by the embodiment of the present application;

Fig. 6 is another circuit diagram of the second switch circuit provided by the embodiment of the present application;

Fig. 7 is the second partial schematic diagram of the electric vehicle DC charging system provided by the embodiment of the present application.

Detailed ways

The implementation manner of the present application will be further described in detail below with reference to the drawings and embodiments. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

In the description of the embodiments of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right" , "vertical", "horizontal", "top", "bottom", "inner", "outer" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing this The application embodiments and simplified descriptions do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of the embodiments of this application, it should be noted that unless otherwise specified and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, Or integrated connection; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present application in specific situations.

In the embodiment of the present application, unless otherwise clearly specified and limited, the first feature may be in direct contact with the first feature or the first feature and the second feature may pass through the middle of the second feature. Media indirect contact. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structures, materials or features are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

The electric vehicle DC charging system, electric vehicle and DC charging method of the present application will be described below with reference to FIGS. 1 to 7 .

According to the embodiment of the first aspect of the present application, as shown in FIG. 1, the electric vehicle DC charging system is suitable for connecting with an adapter, and the adapter is suitable for connecting with a DC charging device. The electric vehicle DC charging system includes:

vehicle control module;

The first switch switching module, the first end of the first switch switching module is electrically connected to the communication port of the adapter, the second end of the first switch switching module is electrically connected to the vehicle control module, and the third end of the second switch switching control module Electrically connected with the vehicle OBC;

The resistance detection module is electrically connected with the vehicle control module, and the resistance detection module is electrically connected with the adapter to detect the resistance of the adapter;

The second switch switching module, the first end of the second switch switching module is electrically connected to the power output end of the adapter, the second end of the second switch switching module is electrically connected to the original vehicle battery pack, and the third end of the second switch switching module The terminal is electrically connected to the vehicle control module;

The voltage conversion module is electrically connected between the fourth terminal of the second switch switching module and the original vehicle battery pack;

The first voltage detection module is electrically connected to the first end of the second switch switching module, the first voltage detection module is electrically connected to the vehicle control module, and the first voltage detection module is suitable for detecting that the DC charging equipment is sent to the second switch through the adapter Switch the voltage of the module;

The boost module is electrically connected to the vehicle control module, and the boost module is electrically connected to the DC charging equipment. The boost module is suitable for boosting the initial voltage of the vehicle to a preset voltage and then feeding it to the DC charging equipment.

According to the electric vehicle DC charging system of the embodiment of the present application, when the adapter is connected to the vehicle charging socket, the resistance detection module will detect the resistance of the adapter, and transmit the detection result to the vehicle control module, so that the vehicle control module can judge Whether the current connection with the vehicle charging socket is an adapter. When it is determined that the adapter is connected to the vehicle charging socket, the vehicle control module controls the first end of the first switch switching module to communicate with the second end, so that the communication port of the adapter communicates with the vehicle control module, and the vehicle control module can pass through the adapter. The communication port interacts with the DC charging device.

The vehicle control module obtains the charging voltage of the original vehicle battery pack and the output voltage range of the DC charging equipment, and compares the charging voltage of the original vehicle battery pack with the output voltage range of the DC charging equipment. When the charging voltage of the original car battery pack is within the output voltage range of the DC charging device, the DC charging device is turned on, and the DC charging device outputs a voltage matching the charging voltage of the original car battery pack, and the vehicle control module controls the second switch switching module The first terminal and the second terminal of the battery are connected, and the voltage can be directly transmitted to the original vehicle battery pack through the adapter and the second switch switching module to realize charging of the original vehicle battery pack.

When the charging voltage of the original car battery pack is not within the output voltage range of the DC charging device, the vehicle control module controls the boost module to boost the initial voltage of the vehicle to a preset voltage, and use the preset voltage as a virtual original car battery pack The charging voltage is sent to the DC charging device. Since the preset voltage is within the output voltage range of the DC charging device, the DC charging device can be turned on normally. At this time, the vehicle control module will send a corresponding signal to the DC charging device, so that the DC charging device will The output voltage is adjusted to the charging voltage of the original car battery pack. The voltage output by the DC charging device is sent to the second switching module through the adapter, and the first voltage detection module will perform voltage detection at this time. If the voltage detected by the first voltage detection module is consistent with the charging voltage of the original vehicle battery pack, it means that the DC charging device has successfully adjusted the output voltage to the charging voltage of the original vehicle battery pack, and the vehicle control module controls the second switching module. One end is connected with the second end, so that the voltage can be directly transmitted to the original vehicle battery pack through the adapter and the second switch switching module, so as to realize charging of the original vehicle battery pack. If the voltage detected by the first voltage detection module does not match the charging voltage of the original vehicle battery pack, it means that the DC charging device has not adjusted the output voltage to the charging voltage of the original vehicle battery pack, and the vehicle control module controls the second switch switching module The first terminal and the fourth terminal are connected, so that the voltage output by the DC charging device is transmitted to the voltage conversion module through the adapter and the second switch module, and the voltage conversion module converts the voltage into the charging voltage of the original car battery pack and then transmits it to the The original car battery pack realizes the charging of the original car battery pack. Furthermore, this application realizes the automatic detection of the adapter, and based on the detection result of the adapter, controls the vehicle to switch from AC charging to DC charging, and in some cases can directly perform low-voltage DC charging on the original vehicle battery pack without using the DC/DC module. Charging, the solution is simpler.

It can be understood that when the resistance value detected by the resistance detection module is consistent with the preset resistance value of the adapter, it means that the adapter connected to the vehicle charging socket at this time is not a DC charging device.

It can be understood that when the adapter is not connected to the vehicle charging socket, but the AC charging device is directly connected to the vehicle charging socket, the on-board OBC can be controlled to charge the original vehicle battery pack.

It can be understood that the initial voltage is the normal voltage of the vehicle, which can be 12V, 24V, 48V, or any other suitable voltage.

It can be understood that the preset voltage is, for example, 300V or any other voltage within the output voltage range of the DC charging device.

In an embodiment of the present application, as shown in FIG. 7 , various ports of the DC adapter are shown in the figure. Specifically, the adapter includes DC+, DC-, S+, S-, CC2, CC1, A+, A-, L1, N, L2, L3, CC, CP and two ground ports PE, DC+, DC-, S+, S-, CC2, CC1, A+, A- and one of the grounding ports PE are used to connect to DC charging equipment, L1, N, L2, L3, CC, CP and the other grounding port PE are used to connect to the charging socket of the vehicle . Among them, DC+ and DC- are the power input ports of the adapter, S+ and S- are the communication access ports, L1 and N are the first power output ports of the adapter, L2 and L3 are the second power output ports of the adapter, CC and CP are communication output ports.

In one embodiment of the present application, both the CC port and the PE port of the adapter are electrically connected to the resistance detection module, and the resistance detection module is adapted to detect the resistance value at the CC port and the PE port of the adapter. When in use, the resistance detection module can detect the resistance value of the CC port and the PE port of the adapter. Compared with the detection of the DC charging device by detecting the CC port in the related art, this application directly detects the DC charging equipment of the adapter. The detection of the resistance value between the two ports can more accurately detect the resistance of the adapter, so that the vehicle control module can more accurately determine whether the adapter is connected to the vehicle charging socket.

Exemplarily, the resistance detection module can detect the voltage between the CC port and the PE port of the adapter, and by judging the resistance value corresponding to the voltage, the resistance value between the CC port and the PE port of the adapter can be obtained.

In one embodiment of the present application, as shown in FIG. 7, the first switching module includes a first switching element, a second switching element, a third switching element, and a fourth switching element, and the first switching element is electrically connected to the The CC port and the vehicle OBC, the second switch element is electrically connected to the CC port of the adapter and the vehicle control module, the third switch element is electrically connected to the CP port of the adapter and the vehicle OBC, and the fourth switch element is electrically connected to the CP port of the adapter and the vehicle control module.

When in use, the vehicle control module can respectively control the opening and closing of the first switch element, the second switch element, the third switch element and the fourth switch element. After the charging socket is connected, the vehicle control module controls the second switch element and the fourth switch element to close, so that the CC port and the CP port of the adapter communicate with the vehicle control module, and the vehicle control module can interact with the DC charging device through the adapter. When the adapter is not plugged into the vehicle charging socket, AC charging is the default, and the vehicle control module controls the first switch element and the third switch element to be closed, so that the vehicle-mounted OBC can pass the first switch element and the third switch element and the AC charging device An interaction occurs. The application realizes that according to the detection result of the resistance detection module, it can be judged whether the adapter is inserted into the vehicle charging socket, and then the vehicle can be controlled to automatically switch between the DC charging circuit and the AC charging circuit.

It should be noted that the first switch element, the second switch element, the third switch element and the fourth switch element can also be closed at the same time, that is, the vehicle control module and the vehicle OBC are connected to the adapter at the same time, and the vehicle OBC and the vehicle control module can be At the same time, it interacts with the DC charging device.

In one embodiment of the present application, the second switching module includes a fifth switching element, the first end of the fifth switching element is electrically connected to the power output end of the adapter, and the second end of the fifth switching element is connected to the original vehicle battery Including electrical connection, the third end of the fifth switch element is electrically connected to the vehicle control module, the fourth end of the fifth switch element is electrically connected to the voltage conversion module, and the vehicle control module is suitable for controlling the fifth switch element between the first state and the second state. Switch between two states, wherein, in the first state, the fifth switch element is connected to the power output end of the adapter and the original vehicle battery pack, and in the second state, the fifth switch element is connected to the power output end of the adapter and the voltage conversion module .

When the charging voltage of the original car battery pack is within the output voltage range of the DC charging device, the DC charging device can directly output a voltage that matches the charging voltage of the original car battery pack, or when the first voltage detection module detects the When the voltage at the fifth switching element is consistent with the charging voltage of the original car battery pack, the vehicle control module controls the fifth switching element to be in the first state, so that the power output end of the adapter is directly connected to the original car battery pack, and the DC charging device can be directly connected to the original car battery pack. Charge the original car battery pack. When the first voltage detection module detects that the voltage value is not within the charging range of the original vehicle battery pack, it means that electricity cannot be directly delivered to the original vehicle battery pack at this time, and the vehicle control module controls the fifth switch element to be in the second state. The power output end of the adapter is connected to the voltage conversion module, and the DC charging device transmits electricity to the voltage conversion module. After the voltage conversion module converts the voltage, it outputs a voltage that meets the charging requirements of the original car battery pack to the original car battery pack. It can prevent the original car battery pack from being damaged.

Moreover, the second switch switching module and the first voltage detection module can also be used for the insulation detection of the charging pile: control the DC charging equipment to output the maximum voltage, and the voltage output by the DC charging equipment can be sent to the second switching switching module through the adapter. When the second switch switching module is in the disconnected state, the first voltage detection module detects the voltage and sends the detected voltage to the DC charging device, and the DC charging device can compare the detected voltage with the maximum output voltage of the DC charging device For comparison, if the two are different, disconnect the DC+ and DC- power output terminals of the DC charging device.

In one embodiment of the present application, the first switching element, the second switching element, the third switching element, the fourth switching element and the fifth switching element are, for example, relays.

In one embodiment of the present application, as shown in Figure 2, the electric vehicle DC charging system includes a third switch switching module, the first end of the third switch switching module is electrically connected to the power output end of the adapter, and the third switch switches The second end of the module is electrically connected to the vehicle-mounted OBC, the vehicle-mounted control module is electrically connected to the third switching module, and the vehicle-mounted OBC is electrically connected to the original vehicle battery pack.

When in use, the first voltage detection module detects the voltage delivered by the DC charging equipment to the second switch switching module through the adapter, when the voltage detected by the first voltage detection module is within the charging voltage range of the original car battery pack , the vehicle control module controls the connection between the first end and the second end of the second switch switching module, so that the electric energy of the DC charging device can be directly transmitted to the original vehicle battery pack through the adapter and the second switch switching module, realizing the replacement of the original vehicle battery pack DC charging. When the voltage detected by the first voltage detection module is not within the charging voltage range of the original vehicle battery pack, the vehicle control module controls the first terminal and the second terminal of the second switch switching module to be disconnected, and the first terminal of the second switch switching module One end is connected to the fourth end, so that the electric energy of the DC charging equipment is transmitted to the voltage conversion module through the adapter and the second switch switching module, and the voltage conversion module converts the voltage of the DC charging equipment to the charging voltage range value of the original car battery pack After that, it is delivered to the original car battery pack to realize DC charging of the original car battery pack. When the voltage detected by the first voltage detection module exceeds the processing capacity of the voltage conversion module, that is, the voltage conversion module cannot convert the current voltage, the vehicle control module will control the first terminal and the second terminal of the third switch switching module. The terminal is connected, so that the voltage output by the DC charging equipment is transmitted to the vehicle OBC through the adapter, and the vehicle OBC converts the voltage to the charging voltage range of the original vehicle battery pack, and then transmits it to the original vehicle battery pack to realize the original vehicle battery pack. DC charging function. That is to say, when the output voltage of the DC charging device is too high, the on-board OBC can be used to realize the DC charging of the original car battery pack; when the output voltage of the DC charging device is higher than the charging voltage range of the original car battery pack, but When the processing capacity of the voltage conversion module is within the range, the voltage conversion module can be used to convert the voltage to charge the original car battery pack, and also realize the DC charging of the original car battery pack; when the output voltage of the DC charging device is within the range of the original car battery When the charging voltage of the battery pack is within the range, the voltage can be directly transmitted to the original car battery pack to realize DC charging of the original car battery pack.

It should be noted that the third switch switching module can also switch on and off in any other suitable situation, and the vehicle-mounted OBC can also play other functions, not limited to the functions described above.

It should be noted that the on-vehicle OBC in this embodiment is an AC-DC dual-purpose OBC, and the AC-DC dual-purpose OBC is an existing module, which will not be described in detail here.

In one embodiment of the present application, the electric vehicle DC charging system includes a second voltage detection module, the second voltage detection module is electrically connected to the first end of the third switch switching module, and the second voltage detection module is electrically connected to the vehicle control module , the second voltage detection module is used to detect the magnitude of the voltage sent by the DC charging equipment to the third switch switching module through the adapter.

When in use, the vehicle-mounted OBC is connected to the communication port of the adapter, and the vehicle-mounted OBC can interact with the DC charging device. The second voltage detection module can detect the voltage delivered to the third switch switching module by the DC charging equipment, and transmit the detection result to the vehicle control module. When the voltage detected by the second voltage detection module is within the input voltage of the vehicle OBC When the value is within the range, the vehicle control module controls the connection between the first terminal and the second terminal of the third switch switching module, so that the voltage can be transmitted to the on-board OBC, and then the original vehicle battery pack is charged after being processed by the on-board OBC. When the voltage detected by the second voltage detection module is not within the input voltage range of the on-board OBC, it means that the DC charging device at this time is not suitable for the current vehicle or the DC charging device has failed, then the vehicle control module controls the third switch The switching module is in a disconnected state to avoid excessive voltage being sent to the on-board OBC and causing damage to the on-board OBC.

And the third switch switching module and the second voltage detection module can also be used for the insulation detection of the charging pile: control the DC charging equipment to output the maximum voltage, and the voltage output by the DC charging equipment can be sent to the third switching switching module through the adapter. When the third switch switching module is in the disconnected state, the second voltage detection module detects the voltage and sends the detected voltage to the DC charging device, and the DC charging device can compare the detected voltage with the maximum output voltage of the DC charging device For comparison, if the two are different, disconnect the DC+ and DC- power output terminals of the DC charging device.

In one embodiment of the present application, as shown in Figure 2, the electric vehicle DC charging system includes a vehicle-mounted step-down power supply, the input end of the vehicle-mounted step-down power supply is electrically connected to the vehicle-mounted OBC, and the output terminal of the vehicle-mounted step-down power supply is suitable for Electrically connected with the on-board equipment, the on-board OBC is adapted to transmit electric energy to the on-board step-down power supply, so that the on-board step-down power supply can charge the on-board device.

When in use, the DC charging device transmits the voltage to the original car battery pack through the adapter. While DC charging the original car battery pack, the adapter also transmits the voltage to the on-board OBC, and the on-board OBC transmits the voltage to the on-board step-down The power supply enables the on-board step-down power supply to supply power or charge the on-board equipment, so that when the user is charging the vehicle, the power consumed by the on-board equipment is not the power of the original car battery pack, which can speed up the charging speed of the original car battery pack. And it can also charge the on-board equipment while charging the original car battery pack, which increases the charging capacity of the vehicle, so that the on-board equipment does not need to consume the power of the original car battery pack for a certain period of time in subsequent use, and improves the vehicle's battery life. recharge mileage.

It is understandable that some vehicle-mounted devices have their own power supply modules, which can then be charged.

In one embodiment of the present application, as shown in FIG. 3 , the vehicle-mounted step-down power supply includes a low-power switching circuit for the vehicle-mounted step-down power supply, and the low-power consumption switching circuit for the vehicle-mounted step-down power supply is suitable for electrical connection with at least two vehicle-mounted devices. The two vehicle-mounted devices are respectively the first vehicle-mounted device and the second vehicle-mounted device, and the low-power switching circuit of the vehicle-mounted step-down power supply includes a single-chip microcomputer 1, a power-off detection circuit and at least two switch circuits, and the at least two switch circuits are the first switch circuit 2 and a second switch circuit 3;

The control end of the first switch circuit 2 is electrically connected to the single-chip microcomputer 1, one end of the first switch circuit 2 is electrically connected to the first power supply, and the other end of the first switch circuit 2 is electrically connected to the first vehicle-mounted equipment, and the first switch circuit 2 is suitable for for controlling whether the first power supply supplies power to the first vehicle-mounted device;

The control end of the second switch circuit 3 is electrically connected to the single-chip microcomputer 1, one end of the second switch circuit 3 is electrically connected to the second power supply, the other end of the second switch circuit 3 is electrically connected to the second vehicle-mounted equipment, and the first MOS transistor Q1 is suitable for for controlling whether the second power supply supplies power to the second vehicle-mounted device;

The power-off detection circuit is electrically connected to the first vehicle-mounted device and the second vehicle-mounted device respectively, and the power-off detection circuit is adapted to detect whether the first vehicle-mounted device and the second vehicle-mounted device are powered off.

According to the low-power switching circuit of the vehicle-mounted step-down power supply of the embodiment of the present application, the power-off detection circuit detects in real time whether the first vehicle-mounted device and the second vehicle-mounted device have been powered off, that is, whether they are in a non-working state, and transmit the detection data to Microcontroller1. When the power-off detection circuit detects that the first vehicle-mounted device has been powered off, the single-chip microcomputer 1 controls the first switch circuit 2 to be in a cut-off state through the control terminal of the first switch circuit 2, so that the first power supply stops supplying power to the first vehicle-mounted device, avoiding The first in-vehicle device continues to consume power. When the power-off detection circuit detects that the second vehicle-mounted device has been powered off, the single-chip microcomputer 1 controls the second switch circuit 3 to be in a cut-off state through the control terminal of the second switch circuit 3, so that the second power supply stops supplying power to the second vehicle-mounted device, avoiding The second in-vehicle device continues to consume power. Furthermore, it is realized to detect in time whether the vehicle-mounted equipment has been powered off, and the power supply of the vehicle-mounted equipment can be disconnected in time to prevent the vehicle-mounted equipment from continuing to consume power, which can effectively save electric energy, and the first switch circuit 2 and the second switch circuit 3 are respectively connected A vehicle-mounted device, and then can individually control the power on and off of one or more of the vehicle-mounted devices. It can also avoid useless power consumption generated by the on-board equipment when the vehicle is charging, and can improve the charging efficiency of the vehicle.

It should be noted that the power-off detection circuit can be any suitable circuit with a power-off detection function. The improvement of this application is to apply the power-off detection circuit to the circuit of the vehicle-mounted step-down power supply to realize whether the vehicle-mounted equipment is powered off. detection, so as to cut off the power supply of the vehicle equipment in time.

In one embodiment of the present application, as shown in FIG. 4, the first switch circuit is, for example, a first MOS transistor switch circuit, and the first MOS transistor switch circuit includes a first connection terminal, a first resistor R1, a second resistor R2 and The first MOS transistor Q1, the first connection end is electrically connected to the sixty-second end of the microcontroller 1 and one end of the first resistor R1, the other end of the first resistor R1 is electrically connected to the gate of the first MOS transistor Q1, and the second resistor One end of R2 is electrically connected to the gate of the first MOS transistor Q1, the other end of the second resistor R2 is electrically connected to the source of the first MOS transistor Q1, the source of the first MOS transistor Q1 is electrically connected to the first power supply, and the second resistor R2 is electrically connected to the source of the first MOS transistor Q1. A drain of a MOS transistor Q1 is electrically connected to the first vehicle-mounted device.

It can be understood that, through the sixty-second terminal and the first connection terminal, the single-chip microcomputer 1 can send a corresponding control signal to the first MOS transistor switch circuit, so that the first MOS transistor Q1 is switched between the on state and the off state, The source of the first MOS transistor Q1 is electrically connected to the first power supply, and the drain of the first MOS transistor Q1 is electrically connected to the first vehicle-mounted device. When the first MOS transistor Q1 is in a cut-off state, the first power supply and the first The in-vehicle devices are disconnected, that is, the first power supply cannot supply power to the first in-vehicle device, so that power consumption can be avoided when the first in-vehicle device is not in use.

It should be noted that the first switch circuit may also be a relay circuit.

In the embodiment of the present application, as shown in FIG. 4, the first MOS transistor switch circuit includes a first inductor L1, one end of the first inductor L1 is electrically connected to the source of the first MOS transistor Q1, and the other end of the first inductor L1 One end is electrically connected to the drain of the first MOS transistor Q1.

It can be understood that, by electrically connecting the first inductor L1 to the source and drain of the first MOS transistor Q1, the first inductor L1, the first MOS transistor Q1, the first resistor R1 and the second resistor R2 together form the first inductor L1. A MOS tube switch circuit, the first inductor L1 can play a filtering role, and the setting of the first inductor L1 can make the first MOS tube switch circuit more stable and reliable.

In one embodiment of the present application, as shown in FIG. 4, the second switch circuit is, for example, a second MOS transistor switch circuit, and the second MOS transistor switch circuit includes a second connection terminal, a third resistor R3, a fourth resistor R4 and The second MOS transistor Q2, the second connection end is electrically connected to the sixty-second end of the microcontroller 1 and one end of the third resistor R3, the other end of the third resistor R3 is electrically connected to the gate of the second MOS transistor Q2, and the fourth resistor One end of R4 is electrically connected to the gate of the second MOS transistor Q2, the other end of the fourth resistor R4 is electrically connected to the source of the second MOS transistor Q2, and the source of the second MOS transistor Q2 is electrically connected to the second power supply. The drains of the two MOS transistors Q2 are electrically connected to the second vehicle equipment.

It can be understood that, through the sixty-second terminal and the second connection terminal, the single-chip microcomputer 1 can send a corresponding control signal to the second MOS transistor switch circuit, so that the second MOS transistor Q2 is switched between the on state and the off state, The source of the second MOS transistor Q2 is electrically connected to the second power supply, and the drain of the second MOS transistor Q2 is electrically connected to the second vehicle equipment. When the second MOS transistor Q2 is in a cut-off state, the second power supply and the second The in-vehicle devices are disconnected, that is, the second power supply cannot supply power to the second in-vehicle device, so that power consumption can be avoided when the second in-vehicle device is not in use.

It should be noted that the second switch circuit may also be a relay circuit.

In the embodiment of the present application, as shown in FIG. 4, the second MOS transistor switch circuit includes a second inductor L2, one end of the second inductor L2 is electrically connected to the source of the second MOS transistor Q2, and the other end of the second inductor L2 One end is electrically connected to the drain of the second MOS transistor Q2.

It can be understood that, by electrically connecting the second inductor L2 to the source and drain of the second MOS transistor Q2, the second inductor L2, the second MOS transistor Q2, the third resistor R3 and the fourth resistor R4 together form a first In the two MOS tube switching circuit, the second inductance L2 can function as a filter, and the setting of the second inductance L2 can make the second MOS tube switching circuit more stable and reliable.

In one embodiment of the present application, as shown in FIG. 5 , the first MOS transistor switch circuit includes a third connection terminal, a third MOS transistor Q3, a fifth resistor R5, a sixth resistor R6, and a first capacitor C1. The connection end is electrically connected to the sixty-second end of the single chip microcomputer 1 and one end of the fifth resistor R5, the other end of the fifth resistor R5 is electrically connected to the gate of the third MOS transistor Q3, and one end of the sixth resistor R6 is connected to the fifth resistor R5 One end of the sixth resistor R6 is electrically connected to the source of the MOS tube, one end of the first capacitor C1 is electrically connected to the other end of the fifth resistor R5, and the other end of the first capacitor C1 is connected to the third MOS tube The source of Q3 is electrically connected, the source of the third MOS transistor Q3 is electrically connected to the first power supply, and the drain of the third MOS transistor Q3 is electrically connected to the first vehicle equipment. When in use, the single-chip microcomputer 1 can control the first MOS transistor switch circuit through the third connection terminal, and electrically connect the fifth resistor R5 and the first capacitor C1 to the third MOS transistor Q3 respectively, so that the first capacitor C1, the third MOS transistor Q3 and the fifth resistor R5 form a first MOS transistor switch circuit, so that the first MOS transistor switch circuit can limit the surge current when the first power supply is turned on.

In one embodiment of the present application, as shown in FIG. 6, the second MOS transistor switch circuit includes a fourth connection terminal, a fourth MOS transistor Q4, a seventh resistor R7, an eighth resistor R8, and a second capacitor C2. The connection terminal is electrically connected to the forty-third terminal of the single chip microcomputer 1 and one end of the seventh resistor R7, the other end of the seventh resistor R7 is electrically connected to the gate of the fourth MOS transistor Q4, and one end of the eighth resistor R8 is connected to the seventh resistor R7 One end of the eighth resistor R8 is electrically connected to the source of the MOS tube, one end of the second capacitor C2 is electrically connected to the other end of the seventh resistor R7, and the other end of the second capacitor C2 is connected to the fourth MOS tube The source of Q4 is electrically connected, the source of the fourth MOS transistor Q4 is electrically connected to the second power supply, and the drain of the fourth MOS transistor Q4 is electrically connected to the second vehicle equipment. When in use, the single-chip microcomputer 1 can control the second MOS transistor switch circuit through the fourth connection terminal, and electrically connect the seventh resistor R7 and the second capacitor C2 to the fourth MOS transistor Q4 respectively, so that the second capacitor C2, the fourth MOS transistor Q4 and the seventh resistor R7 form a second MOS transistor switch circuit, so that the second MOS transistor switch circuit can limit the surge current when the second power supply is turned on.

In one embodiment of the present application, the first MOS transistor switch circuit includes a fifth connection terminal, a fifth MOS transistor and a ninth resistor, and the fifth connection terminal is electrically connected to the sixty-second terminal of the microcontroller 1 and the fifth MOS transistor. The gate and the two ends of the ninth resistor are respectively electrically connected to the source and drain of the fifth MOS transistor, the source of the fifth MOS transistor is electrically connected to the first power supply, and the drain of the fifth MOS transistor is electrically connected to the first vehicle equipment electric connect. When in use, the single-chip microcomputer 1 can control the first MOS transistor switching circuit through the fifth connection terminal, and electrically connect the two ends of the ninth resistor to the source and drain of the fifth MOS transistor respectively, so that the fifth MOS transistor and the ninth MOS transistor The resistors form the first MOS transistor switch circuit, and the setting of the ninth resistor enables the first MOS transistor switch circuit to limit the surge current when the first power supply is turned on.

In one embodiment of the present application, the second MOS transistor switch circuit includes a sixth connection terminal, a sixth MOS transistor and a tenth resistor, and the sixth connection terminal is electrically connected to the forty-third terminal of the microcontroller 1 and the sixth MOS transistor. The gate and the two ends of the tenth resistor are respectively electrically connected to the source and drain of the sixth MOS transistor, the source of the sixth MOS transistor is electrically connected to the second power supply, and the drain of the sixth MOS transistor is electrically connected to the second vehicle equipment electrical connect. When in use, the single-chip microcomputer 1 can control the second MOS transistor switching circuit through the sixth connection terminal, and electrically connect the two ends of the tenth resistor to the source and drain of the sixth MOS transistor respectively, so that the sixth MOS transistor and the tenth MOS transistor The resistors form the second MOS transistor switch circuit, and the setting of the tenth resistor enables the second MOS transistor switch circuit to limit the surge current when the second power supply is turned on.

According to an embodiment of the second aspect of the present application, an electric vehicle includes the above-mentioned DC charging system for an electric vehicle.

According to the electric vehicle of the embodiment of the present application, it has an electric vehicle DC charging system, which realizes the automatic detection of the adapter, and based on the detection result of the adapter, controls the vehicle to switch from AC charging to DC charging, and realizes that DC/DC is not required. Module, you can directly use the AC charging socket to charge the original car battery pack with low-voltage DC, and the solution is simpler.

In one embodiment of the present application, the electric vehicle DC charging system includes a third voltage detection module, the third voltage detection module is electrically connected to the power input end of the adapter, and the power input end of the adapter is electrically connected to the DC charging device. The three voltage detection modules are connected with the vehicle control module, and the third voltage detection module is suitable for detecting the voltage delivered to the adapter by the DC charging equipment.

When in use, the third voltage detection module can detect the voltage delivered to the adapter by the DC charging equipment, and transmit the detection result to the vehicle control module. When the voltage detected by the third voltage detection module is zero, it means that the DC The charging device has stopped outputting voltage. When the charging of the vehicle is completed, the vehicle control module can know whether the DC charging device has been powered off according to the detection result of the third voltage detection module, that is, whether the DC charging device has stopped outputting voltage. After determining that the DC charging device has stopped outputting voltage, the vehicle The control module is entering the sleep mode, so as to prevent the vehicle control module from entering the sleep mode before the DC charging device is completely powered off.

It can be understood that the connection between the third voltage detection module and the vehicle control module may be a communication connection, a direct electrical connection, or a connection through other components.

In one embodiment of the present application, a fourth switching module is provided between the adapter and the DC charging equipment, the first end of the fourth switching module is electrically connected to the DC charging equipment, and the second end of the fourth switching module It is electrically connected with the adapter, and the adapter control module is arranged in the adapter, and the adapter control module is electrically connected with the fourth switch switching module, and the third voltage detection module is electrically connected with the adapter control module.

When in use, the third voltage detection module detects the voltage delivered to the adapter by the DC charging device, and transmits the detection data to the adapter control module. When the voltage detected by the third voltage detection module is within the safe working voltage of the adapter When within the range, the adapter control module controls the fourth switch switching module to close, so that the first end and the second end of the fourth switch switching module are connected, and the DC charging device can transmit the voltage to the adapter. The application realizes the detection of the output voltage of the DC charging device, and only when the detected voltage is within the safe working voltage of the adapter, the voltage is delivered to the adapter, ensuring the safety of the adapter.

According to an embodiment of the third aspect of the present application, a DC charging method for an electric vehicle includes:

Obtain the detection data of the resistance detection module, and confirm that the adapter is connected to the vehicle charging socket;

Obtain the charging voltage of the original car battery pack;

Obtain the output voltage of the DC charging device;

If the difference between the charging voltage and the output voltage is within the preset range, the output voltage is controlled to charge the original car battery pack;

If the difference between the charging voltage and the output voltage is not within the preset range, the control output voltage is sent to the voltage conversion module, and the control voltage conversion module converts the output voltage into a preset voltage to charge the original vehicle battery pack.

Furthermore, the automatic detection of the adapter is realized, and based on the detection result of the adapter, the vehicle is controlled to switch from AC charging to DC charging, and in some cases, the original vehicle battery pack can be directly charged with low-voltage DC without using the DC/DC module. The scheme is simpler.

According to an embodiment of the present application, the electric vehicle DC charging method includes:

Determine the target vehicle-mounted equipment, the target vehicle-mounted equipment has the function of electric energy storage;

The control adapter transmits the voltage of the DC charging equipment to the on-board OBC;

Control the on-board OBC to deliver the voltage to the on-board step-down power supply;

Control the on-board step-down power supply to charge the target on-board equipment.

The DC charging equipment transmits the voltage to the original car battery pack through the adapter. While DC charging the original car battery pack, the adapter also transmits the voltage to the on-board OBC, and the on-board OBC transmits the voltage to the on-board step-down power supply, making the on-board The step-down power supply can charge the target on-board equipment, so that the user can charge the on-board equipment when the vehicle is charging, increasing the charging capacity of the vehicle, so that the on-board equipment does not need to consume the power of the original car battery pack for a certain period of subsequent use , improving the cruising range of the vehicle.

Finally, it should be noted that the above embodiments are only used to illustrate the present application, but not to limit the present application. Although the present application has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications or equivalent replacements of the technical solutions of the present application do not depart from the spirit and scope of the technical solutions of the present application, and all should cover within the scope of the claims of this application.

Claims (10)

1. A DC charging system for an electric vehicle, suitable for being connected with an adapter, the adapter being suitable for connecting with a DC charging device, characterized in that it comprises: vehicle control module; A first switch switching module, the first end of the first switch switching module is electrically connected to the communication port of the adapter, the second end of the first switch switching module is electrically connected to the vehicle control module, and the first switch switching module is electrically connected to the vehicle control module. The third end of the second switch switching control module is electrically connected to the vehicle-mounted OBC; a resistance detection module electrically connected to the vehicle control module, the resistance detection module is electrically connected to the adapter to detect the resistance of the adapter; The second switch switching module, the first end of the second switch switching module is electrically connected to the power output end of the adapter, the second end of the second switch switching module is electrically connected to the original car battery pack, the The third end of the second switch switching module is electrically connected to the vehicle control module; A voltage conversion module, electrically connected between the fourth terminal of the second switching module and the original vehicle battery pack; The first voltage detection module is electrically connected to the first end of the second switch switching module, the first voltage detection module is electrically connected to the vehicle control module, and the first voltage detection module is suitable for detecting the direct current The voltage delivered by the charging device to the second switch switching module via the adapter; The boost module is electrically connected to the vehicle control module, the boost module is electrically connected to the DC charging device, and the boost module is suitable for boosting the initial voltage of the vehicle to a preset voltage and then delivering it to the DC charging equipment. 2. The electric vehicle DC charging system according to claim 1, wherein the first switching module comprises a first switching element, a second switching element, a third switching element and a fourth switching element, the first switching element A switch element is electrically connected to the CC port of the adapter and the vehicle OBC, the second switch element is electrically connected to the CC port of the adapter and the vehicle control module, and the third switch element is electrically connected to the The CP port of the adapter is connected to the vehicle OBC, and the fourth switch element is electrically connected to the CP port of the adapter and the vehicle control module. 3. The electric vehicle DC charging system according to claim 1, wherein the second switching module includes a fifth switching element, the first end of the fifth switching element is connected to the power output of the adapter Terminals are electrically connected, the second terminal of the fifth switching element is electrically connected to the original vehicle battery pack, the third terminal of the fifth switching element is electrically connected to the vehicle control module, and the fifth switching element The fourth end is electrically connected to the voltage conversion module, and the vehicle control module is adapted to control the fifth switch element to switch between a first state and a second state, wherein, in the first state, the first The fifth switch element is connected to the power output end of the adapter and the original vehicle battery pack, and in the second state, the fifth switch element is connected to the power output end of the adapter to the voltage conversion module. 4. The electric vehicle DC charging system according to any one of claims 1 to 3, wherein the electric vehicle DC charging system comprises a third switching module, the first end of the third switching module is connected to The power output end of the adapter is electrically connected, the second end of the third switch switching module is electrically connected to the vehicle-mounted OBC, the vehicle-mounted control module is electrically connected to the third switch switching module, and the vehicle-mounted OBC It is electrically connected with the original car battery pack. 5. The electric vehicle DC charging system according to claim 4, characterized in that, the electric vehicle DC charging system comprises a second voltage detection module, the second voltage detection module and the third switching module of the third switch One end is electrically connected, the second voltage detection module is electrically connected to the vehicle control module, and the second voltage detection module is used to detect that the DC charging equipment is sent to the third switch switching module through the adapter voltage size. 6. The DC charging system for electric vehicles according to claim 5, wherein the DC charging system for electric vehicles comprises a vehicle-mounted step-down power supply, the input end of the vehicle-mounted step-down power supply is electrically connected to the vehicle-mounted OBC, so that The output terminal of the vehicle-mounted step-down power supply is suitable for electrical connection with the vehicle-mounted equipment, and the vehicle-mounted OBC is suitable for transmitting electric energy to the vehicle-mounted step-down power supply, so that the vehicle-mounted step-down power supply can charge the vehicle-mounted equipment. 7. An electric vehicle, characterized by comprising the electric vehicle DC charging system according to any one of claims 1 to 6. 8. The electric vehicle according to claim 7, wherein the DC charging system for the electric vehicle comprises a third voltage detection module, the third voltage detection module is electrically connected to the power input end of the adapter, the The power input end of the adapter is electrically connected to the DC charging device, the third voltage detection module is connected to the vehicle control module, and the third voltage detection module is suitable for detecting the The voltage of the adapter. 9. A DC charging method for an electric vehicle based on the DC charging system for an electric vehicle according to any one of claims 1 to 6, characterized in that it comprises: Obtain the detection data of the resistance detection module, and confirm that the adapter is connected to the vehicle charging socket; Obtain the charging voltage of the original car battery pack; Obtain the output voltage of the DC charging device; If the difference between the charging voltage and the output voltage is within a preset range, then controlling the output voltage to charge the original vehicle battery pack; If the difference between the charging voltage and the output voltage is not within the preset interval, the output voltage is controlled to be sent to a voltage conversion module, and the voltage conversion module is controlled to convert the output voltage into a preset voltage to the Charge the original car battery pack. 10. The DC charging method for electric vehicles according to claim 9, characterized in that it comprises: Determining the target vehicle-mounted device, the target vehicle-mounted device has an electric energy storage function; controlling the adapter to deliver the voltage of the DC charging device to the vehicle-mounted OBC; Controlling the on-board OBC to deliver the voltage to the on-board step-down power supply; Controlling the vehicle step-down power supply to charge the target vehicle equipment.