Charging control system and method for electric vehicle

Abstract

The invention discloses a charging control system and method for an electric vehicle. The system comprises a vehicle control unit, a PDU, a charging socket, a first pre-charging relay, a first charging positive relay and a first charging negative relay. The first charging positive relay is connected in series between the positive output end of the PDU and the positive terminal of the charging socket, the first charging negative relay is connected in series between the negative output end of the PDU and the negative terminal of the charging socket, and the first pre-charging relay and the first charging positive relay are arranged in parallel. When a charging socket and a charging plug are plugged for charging, after a power battery charging and discharging loop is connected, a vehicle control unit firstly controls a first pre-charging relay and a first charging negative relay to be closed so as to perform pre-charging through a PDU pre-charging loop; and when the voltage difference between the two ends of the first charging positive relay is smaller than a set value, the first charging positive relay is controlled to be closed, the first pre-charging relay is controlled to be disconnected, and a PDU main charging loop is formed. According to the invention, the compatibility and safety with the charging pile can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle charging control, and more specifically, to a charging control system and method for an electric vehicle. Background Art

[0002] Charging is a very important link for electric vehicles, but there are many types of charging piles on the market, with uneven quality and different charging sequences, which cause the charging relay to burn or stick when closed, causing fire and high-voltage safety hazards, resulting in electric vehicles being incompatible with all charging piles on the market, and there are risks such as failure to charge, damage to electrical components of the charging circuit, and high voltage electricity in the charging circuit. Therefore, how to avoid damage to electrical components of the charging circuit and improve charging safety is of great significance. Summary of the invention

[0003] The present invention provides a charging control system and method for an electric vehicle, which solves the problem that when the existing electric vehicle is charged, a relay may be ablated or adhered when closed, causing fire and high-voltage safety hazards. The control system and method can avoid damage to electrical components of the charging circuit, improve charging safety, and improve compatibility with charging piles.

[0004] To achieve the above objectives, the present invention provides the following technical solutions:

[0005] A charging control system for an electric vehicle, comprising: a vehicle controller, a PDU, a charging socket, a first pre-charging relay, a first charging positive relay and a first charging negative relay;

[0006] The first charging positive relay is connected in series between the positive output end of the PDU and the positive terminal of the charging socket, the first charging negative relay is connected in series between the negative output end of the PDU and the negative terminal of the charging socket, and the first pre-charging relay is arranged in parallel with the first charging positive relay;

[0007] The vehicle controller is signal-connected to the PDU, the PDU is electrically connected to the vehicle battery pack, and the vehicle controller is signal-connected to the control ends of the first pre-charging relay, the first charging positive relay, and the first charging negative relay respectively;

[0008] When the charging socket is connected to the charging plug of the charging pile for charging, after the power battery charging and discharging circuits are connected, the vehicle controller first controls the first pre-charging relay and the first charging negative relay to close, so as to pre-charge through the PDU pre-charging circuit, and controls the first charging positive relay to close when the voltage difference between the two ends of the first charging positive relay is less than a set value, and controls the first pre-charging relay to disconnect, so as to form a PDU main charging circuit, so that the charging pile can charge the power battery in the battery pack.

[0009] Preferably, it further comprises: a second pre-charging relay, a second charging positive relay and a second charging negative relay;

[0010] The second charging positive relay is connected in series between the positive electrode of the power battery and the positive electrode output terminal of the battery pack, the second charging negative relay is connected in series between the negative electrode of the power battery and the negative electrode output terminal of the battery pack, and the second pre-charging relay is arranged in parallel with the second charging positive relay;

[0011] The BMS of the battery pack is respectively connected to the control end signals of the second pre-charging relay, the second charging positive relay and the second charging negative relay, and first controls the second pre-charging relay and the second charging negative relay to close when the power battery is charged or discharged, so as to pre-charge through the battery pack pre-charging circuit, and controls the second charging positive relay to close when the voltage difference between the two ends of the second charging positive relay is less than a set value, and controls the second pre-charging relay to disconnect, so as to make the electrical connection between the power battery and the PDU conductive, thereby forming a main charging circuit for the power battery.

[0012] Preferably, it also includes: a first pre-charging resistor;

[0013] The first pre-charging resistor is connected in series with the first pre-charging relay and then connected in parallel with the first charging positive relay.

[0014] Preferably, it also includes: a second pre-charging resistor;

[0015] The second pre-charging resistor is connected in series with the second pre-charging relay and then connected in parallel with the second charging positive relay.

[0016] Preferably, it further comprises: a third charging positive relay and a third charging negative relay;

[0017] The third charging positive relay is connected in series between the positive output end of the power conversion unit in the charging pile and the positive terminal of the charging plug of the charging pile;

[0018] The third negative charging relay is connected in series between the negative output end of the power conversion unit in the charging pile and the negative terminal of the charging plug of the charging pile;

[0019] The charging pile controller is respectively connected to the control end signals of the third charging positive relay and the third charging negative relay, and controls the third charging positive relay and the third charging negative relay to close after the vehicle end completes the charging preparation, so as to conduct the electrical connection between the charging pile and the power battery.

[0020] Preferably, corresponding communication connection terminals are provided in the electrical socket and the charging plug, the charging pile controller is signal-connected to the communication connection terminal in the charging plug, and the whole vehicle controller is signal-connected to the communication connection terminal in the charging socket, and when the charging plug and the charging socket are plugged together, the communication connection between the charging pile controller and the whole vehicle controller is conducted.

[0021] The present invention also provides a charging control method for an electric vehicle, using the above-mentioned charging control system, comprising:

[0022] After the charging plug is connected to the charging socket, the charging pile and the electric vehicle are respectively subjected to insulation testing;

[0023] When the insulation test of the charging pile shows no problem, the third charging positive relay and the third charging negative relay are closed to put the charging pile in a charging ready state;

[0024] When the vehicle side has no problem with the insulation detection, the pre-charging circuit in the battery pack is controlled to pre-charge first, and after the pre-charging is completed, the main charging circuit of the power battery is controlled to be turned on;

[0025] After the power main charging circuit is turned on, the PDU pre-charging circuit is controlled to perform pre-charging first, and after the pre-charging is completed, the PDU main charging circuit is controlled to be turned on.

[0026] Preferably, it also includes:

[0027] When the power battery main charging circuit and the PDU main charging circuit are both in conduction, a vehicle charging readiness signal is sent;

[0028] After the charging pile and the vehicle are both in a charging ready state, the charging of the charging pile and the vehicle is controlled through the PP signal and the CP signal.

[0029] Preferably, the method of first controlling the pre-charging circuit in the battery pack to perform pre-charging, and after the pre-charging is completed, controlling the main charging circuit of the power battery to be turned on includes:

[0030] First, the second pre-charging relay and the second negative charging relay are controlled to be closed, so that the pre-charging circuit in the battery pack is turned on for pre-charging;

[0031] After the voltage difference between the two ends of the second charging positive relay is less than the set value, the second charging positive relay is closed and the second pre-charging relay is opened to connect the main charging circuit of the power battery.

[0032] Preferably, the method of first controlling the PDU pre-charging circuit to perform pre-charging, and after the pre-charging is completed, controlling the PDU main charging circuit to be turned on includes:

[0033] First, the first pre-charging relay and the first charging negative relay are controlled to be closed, so that the PDU pre-charging circuit is turned on for pre-charging;

[0034] After the voltage difference between the two ends of the first charging positive relay is less than the set value, the first charging positive relay is closed and the first pre-charging relay is opened to connect the PDU main charging circuit.

[0035] The present invention provides a charging control system and method for an electric vehicle, wherein pre-charging relays are arranged at both ends of a charging positive relay of a PDU and a power battery charging main circuit, and pre-charging control is performed on the PDU and the power battery respectively, so as to solve the problem that when the existing electric vehicle is charged, the relay is ablated or adhered when closed, causing fire and high-voltage safety hazards, and can avoid damage to electrical components of the charging circuit, thereby improving charging safety and compatibility with charging piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below.

[0037] Figure 1 It is a schematic diagram of a charging control system for an electric vehicle provided by the present invention.

[0038] Figure 2 It is a schematic diagram of a charging control method for an electric vehicle provided by the present invention.

[0039] Figure 3 This is a flow chart of charging control provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to enable persons skilled in the art to better understand the solutions of the embodiments of the present invention, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and implementation modes.

[0041] The current charging of electric vehicles is not compatible with different charging piles due to different charging sequences, which easily causes safety hazards. The present invention provides an electric vehicle charging control system and method, which solves the problem that when the existing electric vehicles are charged, the relays are ablated or adhered when closed, causing fire and high-voltage safety hazards, and can avoid damage to the electrical components of the charging circuit, improve charging safety, and improve compatibility with charging piles.

[0042] like Figure 1As shown, a charging control system for an electric vehicle includes: a vehicle controller, a PDU, a charging socket, a first pre-charging relay K8, a first charging positive relay K5, and a first charging negative relay K6. The first charging positive relay K5 is connected in series between the positive output end of the PDU and the positive terminal of the charging socket, the first charging negative relay K6 is connected in series between the negative output end of the PDU and the negative terminal of the charging socket, and the first pre-charging relay K8 is arranged in parallel with the first charging positive relay K5. The vehicle controller is connected to the PDU signal, the PDU is electrically connected to the vehicle battery pack, and the vehicle controller is respectively connected to the control end signals of the first pre-charging relay K8, the first charging positive relay K5, and the first charging negative relay K6. When the charging socket is connected to the charging plug of the charging pile for charging, after the power battery charging and discharging circuits are connected, the vehicle controller first controls the first pre-charging relay K8 and the first charging negative relay K6 to close, so as to pre-charge through the PDU pre-charging circuit, and controls the first charging positive relay K5 to close when the voltage difference between the two ends of the first charging positive relay K5 is less than the set value, and controls the first pre-charging relay K8 to disconnect, so as to form a PDU main charging circuit, so that the charging pile can charge the power battery in the battery pack.

[0043] Specifically, the PDU (Power Distribution Unit), which is also a commonly used high-voltage distribution box, sets a pre-charging circuit in the charging circuit between the PDU and the charging socket, so that the voltage difference between the two ends of the charging positive relay in the charging circuit is less than the set value before closing. The set value takes a smaller value, that is, the voltages at both ends of the charging positive relay are similar, to avoid arcing when the charging positive relay is closed, causing safety hazards. At the same time, the relay closure between the charging pile and the vehicle is controlled separately, so that the vehicle does not restrict the relay control timing of the charging pile, which can enable electric vehicles to cover more charging piles on the market, without causing damage to the electrical components of the charging circuit and safety risks, and will not cause customers to be unable to charge.

[0044] The system also includes: a second pre-charge relay K7, a second charging positive relay K3 and a second charging negative relay K4. The second charging positive relay K3 is connected in series between the positive electrode of the power battery and the positive output terminal of the battery pack, the second charging negative relay K4 is connected in series between the negative electrode of the power battery and the negative output terminal of the battery pack, and the second pre-charge relay K7 is arranged in parallel with the second charging positive relay K3. The BMS of the battery pack is respectively connected to the control end signals of the second pre-charge relay K7, the second charging positive relay K3 and the second charging negative relay K4, and controls the second pre-charge relay K7 and the second charging negative relay K4 to close when the power battery is charged or discharged, so as to pre-charge through the battery pack pre-charge circuit, and controls the second charging positive relay K3 to close when the voltage difference between the two ends of the second charging positive relay K3 is less than the set value, and controls the second pre-charge relay K7 to open, so as to make the electrical connection between the power battery and the PDU conductive, forming the main charging circuit of the power battery.

[0045] The system also includes: a first pre-charging resistor R2; the first pre-charging resistor R2 is connected in series with the first pre-charging relay K8, and then connected in parallel with the first charging positive relay K5.

[0046] The system also includes: a second pre-charging resistor R1; the second pre-charging resistor R1 is connected in series with the second pre-charging relay K7, and then connected in parallel with the second charging positive relay K3.

[0047] Preferably, it also includes: a third charging positive relay K1 and a third charging negative relay K2; the third charging positive relay K1 is connected in series between the positive output end of the power conversion unit in the charging pile and the positive terminal of the charging plug of the charging pile; the third charging negative relay K2 is connected in series between the negative output end of the power conversion unit in the charging pile and the negative terminal of the charging plug of the charging pile.

[0048] The charging pile controller is respectively connected to the control end signals of the third charging positive relay K1 and the third charging negative relay K2, and controls the third charging positive relay K1 and the third charging negative relay K2 to close after the vehicle end completes the charging preparation, so as to conduct the electrical connection between the charging pile and the power battery.

[0049] Furthermore, corresponding communication connection terminals are provided in the electrical socket and the charging plug, the charging pile controller is signal-connected to the communication connection terminal in the charging plug, and the whole vehicle controller is signal-connected to the communication connection terminal in the charging socket. When the charging plug and the charging socket are plugged together, the communication connection between the charging pile controller and the whole vehicle controller is conducted.

[0050] It can be seen that the present invention provides a charging control system for an electric vehicle, in which pre-charging relays are arranged at both ends of the charging positive relays of the PDU and the power battery charging main circuit, and pre-charging control is performed on the PDU and the power battery respectively, thereby solving the problem that when the existing electric vehicles are charged, the relays are burned or stuck when closed, causing fire and high-voltage safety hazards, and can avoid damage to the electrical components of the charging circuit, thereby improving charging safety and compatibility with charging piles.

[0051] like Figure 2 and Figure 3 As shown, accordingly, the present invention also provides a charging control method for an electric vehicle, using the above-mentioned charging control system, comprising:

[0052] S1: After the charging plug is connected to the charging socket, the charging pile and the electric vehicle are respectively subjected to insulation testing.

[0053] S2: When there is no problem with the insulation detection of the charging pile, the third charging positive relay and the third charging negative relay are closed to put the charging pile in a charging ready state.

[0054] S3: When there is no problem with the insulation detection on the vehicle side, the pre-charging circuit in the battery pack is controlled to perform pre-charging first, and after the pre-charging is completed, the main charging circuit of the power battery is controlled to be turned on.

[0055] S4: After the power main charging circuit is turned on, the PDU pre-charging circuit is controlled to perform pre-charging first, and after the pre-charging is completed, the PDU main charging circuit is controlled to be turned on.

[0056] The method further includes:

[0057] When the power battery main charging circuit and the PDU main charging circuit are both turned on, a vehicle charging readiness signal is sent.

[0058] After the charging pile and the vehicle are both in a charging ready state, the charging of the charging pile and the vehicle is controlled through the PP signal and the CP signal.

[0059] Further, the method of first controlling the pre-charging circuit in the battery pack to perform pre-charging, and after the pre-charging is completed, controlling the main charging circuit of the power battery to be turned on, includes:

[0060] First, the second pre-charge relay and the second negative charging relay are controlled to close, so that the pre-charge circuit in the battery pack is turned on for pre-charging. After the voltage difference between the two ends of the second positive charging relay is less than the set value, the second positive charging relay is closed and the second pre-charge relay is disconnected, so that the main charging circuit of the power battery is turned on.

[0061] Further, the method of first controlling the PDU pre-charging circuit to perform pre-charging, and after the pre-charging is completed, controlling the PDU main charging circuit to be turned on includes:

[0062] First, the first pre-charging relay and the first negative charging relay are controlled to close, so that the PDU pre-charging circuit is turned on for pre-charging. After the voltage difference between the two ends of the first positive charging relay is less than the set value, the first positive charging relay is closed and the first pre-charging relay is disconnected, so that the PDU main charging circuit is turned on.

[0063] In actual application, when an electric vehicle needs to be charged, the charging plug on the charging pile is inserted into the charging socket of the electric vehicle. After the insulation test between the charging pile and the electric vehicle is OK, the subsequent charging actions are started: the first step is that the electric vehicle will close the K4 main negative relay and K7 pre-charge relay in the battery pack; the second step is to close the K3 main positive relay and disconnect the K7 pre-charge relay after the pre-charge is completed; the third step is to close the K6 charging negative relay and K8 pre-charge relay in the PDU; the fourth step is to close the K5 charging positive relay in the PDU and disconnect the K8 pre-charge relay; the fifth step is to close the K2 negative relay in the charging pile; the sixth step is to close the K1 positive relay in the charging pile; the seventh step is to start charging. The closing sequence of the K1 positive relay and the K2 negative relay in the charging pile does not need to rely on the closing sequence of the relay in the electric vehicle, and can be closed at any time node, so that electric vehicles can cover more charging piles on the market, without causing damage to the electrical components of the charging circuit and safety risks, and will not cause customers to be unable to charge.

[0064] It can be seen that the present invention provides a charging control method for an electric vehicle, wherein pre-charging relays are arranged at both ends of the charging positive relays of the PDU and the power battery charging main circuit, and pre-charging control is performed on the PDU and the power battery respectively, thereby solving the problem that when the existing electric vehicle is charged, the relay is burned or adhered when closed, causing fire and high-voltage safety hazards, and can avoid damage to the electrical components of the charging circuit, thereby improving charging safety and compatibility with charging piles.

[0065] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the protection scope of the present invention.

Claims

1. A charging control system for an electric vehicle, characterized in that: include: Vehicle controller, PDU, charging socket, first pre-charging relay, first charging positive relay and first charging negative relay; The first charging positive relay is connected in series between the positive output end of the PDU and the positive terminal of the charging socket, the first charging negative relay is connected in series between the negative output end of the PDU and the negative terminal of the charging socket, and the first pre-charging relay is arranged in parallel with the first charging positive relay; The vehicle controller is signal-connected to the PDU, the PDU is electrically connected to the vehicle battery pack, and the vehicle controller is signal-connected to the control ends of the first pre-charging relay, the first charging positive relay, and the first charging negative relay respectively; When the charging socket is connected to the charging plug of the charging pile for charging, after the power battery charging and discharging circuits are connected, the vehicle controller first controls the first pre-charging relay and the first charging negative relay to close, so as to pre-charge through the PDU pre-charging circuit, and controls the first charging relay to close when the voltages at both ends of the first charging positive relay are equal, and controls the first pre-charging relay to disconnect, so as to form a PDU main charging circuit, so that the charging pile can charge the power battery in the battery pack.

2. The charging control system of the electric vehicle according to claim 1, characterized in that: Also includes: a second pre-charge relay, a second charge positive relay, and a second charge negative relay; The second charging positive relay is connected in series between the positive electrode of the power battery and the positive electrode output terminal of the battery pack, the second charging negative relay is connected in series between the negative electrode of the power battery and the negative electrode output terminal of the battery pack, and the second pre-charging relay is arranged in parallel with the second charging positive relay; The BMS of the battery pack is respectively connected to the control end signals of the second pre-charging relay, the second charging positive relay and the second charging negative relay, and first controls the second pre-charging relay and the second charging negative relay to close when the power battery is charged or discharged, so as to pre-charge through the battery pack pre-charging circuit, and controls the second charging relay to close when the voltage difference between the two ends of the second charging positive relay is less than the set value, and controls the second pre-charging relay to disconnect, so as to make the electrical connection between the power battery and the PDU conductive, thereby forming a main charging circuit for the power battery.

3. The charging control system of the electric vehicle according to claim 2, characterized in that: Also includes: A first pre-charge resistor; The first pre-charging resistor is connected in series with the first pre-charging relay and then connected in parallel with the first charging positive relay.

4. The charging control system of the electric vehicle according to claim 3, characterized in that: Also includes: A second pre-charge resistor; The second pre-charging resistor is connected in series with the second pre-charging relay and then connected in parallel with the second charging positive relay.

5. The charging control system of the electric vehicle according to claim 4, characterized in that: Also includes: a third charging positive relay and a third charging negative relay; The third charging positive relay is connected in series between the positive output end of the power conversion unit in the charging pile and the positive terminal of the charging plug of the charging pile; The third negative charging relay is connected in series between the negative output end of the power conversion unit in the charging pile and the negative terminal of the charging plug of the charging pile; The charging pile controller is respectively connected to the control end signals of the third charging positive relay and the third charging negative relay, and controls the third charging positive relay and the third charging negative relay to close after the vehicle end completes the charging preparation, so as to conduct the electrical connection between the charging pile and the power battery.

6. The charging control system of the electric vehicle according to claim 5, characterized in that: The charging socket and the charging plug are both provided with corresponding communication connection terminals, the charging pile controller is signal-connected to the communication connection terminal in the charging plug, and the whole vehicle controller is signal-connected to the communication connection terminal in the charging socket. When the charging plug and the charging socket are plugged together, the communication connection between the charging pile controller and the whole vehicle controller is turned on.

7. A charging control method for an electric vehicle, using the charging control system according to claim 6, characterized in that: include: After the charging plug is connected to the charging socket, the charging pile and the electric vehicle are respectively subjected to insulation testing; When the insulation test of the charging pile shows no problem, the third charging positive relay and the third charging negative relay are closed to put the charging pile in a charging ready state; When the vehicle side has no problem with the insulation detection, the pre-charging circuit in the battery pack is controlled to pre-charge first, and after the pre-charging is completed, the main charging circuit of the power battery is controlled to be turned on; After the power main charging circuit is turned on, the PDU pre-charging circuit is controlled to perform pre-charging first, and after the pre-charging is completed, the PDU main charging circuit is controlled to be turned on.

8. The charging control method for an electric vehicle according to claim 7, characterized in that: Also includes: When the power battery main charging circuit and the PDU main charging circuit are both in conduction, a vehicle charging readiness signal is sent; After the charging pile and the vehicle are both in a charging ready state, the charging of the charging pile and the vehicle is controlled through the PP signal and the CP signal.

9. The charging control method of an electric vehicle according to claim 8, characterized in that: The method of first controlling the pre-charging circuit in the battery pack to perform pre-charging, and after the pre-charging is completed, controlling the main charging circuit of the power battery to be turned on, includes: First, the second pre-charging relay and the second negative charging relay are controlled to be closed, so that the pre-charging circuit in the battery pack is turned on for pre-charging; After the voltage difference between the two ends of the second charging positive relay is less than the set value, the second charging positive relay is closed and the second pre-charging relay is opened to connect the main charging circuit of the power battery.

10. The charging control method of an electric vehicle according to claim 9, characterized in that: The method of first controlling the PDU pre-charging circuit to perform pre-charging, and after the pre-charging is completed, controlling the PDU main charging circuit to be turned on includes: First, the first pre-charging relay and the first charging negative relay are controlled to be closed, so that the PDU pre-charging circuit is turned on for pre-charging; After the voltage difference between the two ends of the first charging positive relay is less than the set value, the first charging positive relay is closed and the first pre-charging relay is opened to turn on the PDU main charging circuit.

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