A charging control system and method for electric vehicles

Abstract

This invention discloses a charging control system and method for electric vehicles. The system includes: a vehicle controller, a power distribution unit (PDU), a charging socket, a first pre-charge relay, a first positive charging relay, and a first negative charging relay. The first positive charging relay is connected in series between the positive output terminal of the PDU and the positive terminal of the charging socket, and the first negative charging relay is connected in series between the negative output terminal of the PDU and the negative terminal of the charging socket. The first pre-charge relay and the first positive charging relay are connected in parallel. When the charging socket and charging plug are plugged in, after the power battery charging and discharging circuit is connected, the vehicle controller first controls the first pre-charge relay and the first negative charging relay to close, so as to perform pre-charging through the PDU pre-charge circuit. When the voltage difference across the first positive charging relay is less than a set value, the vehicle controller controls the first positive charging relay to close and controls the first pre-charge relay to open, forming the PDU main charging circuit. This invention can improve compatibility and safety with charging piles.

Description

Technical Field

[0001] This invention relates to the technical field of electric vehicle charging control, and more specifically, to a charging control system and method for electric vehicles. Background Technology

[0002] Charging is a crucial step for electric vehicles. However, the market is flooded with charging stations of varying types and quality, with inconsistent charging sequences. This can cause charging relays to burn out or stick together when closed, leading to fires and high-voltage safety hazards. Furthermore, electric vehicles may be incompatible with all charging stations on the market, resulting in risks such as inability to charge, damage to electrical components in the charging circuit, or the charging circuit being continuously energized with high voltage. Therefore, preventing damage to electrical components in the charging circuit and improving charging safety is of paramount importance. Summary of the Invention

[0003] This invention provides a charging control system and method for electric vehicles, which solves the problem that relays burn or stick when closed during charging of existing electric vehicles, causing fires and high-voltage safety hazards. It can prevent damage to electrical components in the charging circuit, improve charging safety, and enhance compatibility with charging piles.

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

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

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

[0007] The vehicle controller is connected to the PDU via signal, the PDU is electrically connected to the vehicle battery pack, and the vehicle controller is connected to the control terminal signals of the first pre-charge relay, the first positive charging relay, and the first negative charging relay, respectively.

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

[0009] Preferably, it also includes: a second pre-charge relay, a second positive charging relay, and a second negative charging relay;

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

[0011] The BMS of the battery pack is connected to the control terminals of the second pre-charge relay, the second positive charging relay, and the second negative charging relay, respectively. When the power battery is charging or discharging, it first controls the second pre-charge relay and the second negative charging relay to close, so as to pre-charge through the battery pack pre-charge circuit. When the voltage difference across the second positive charging relay is less than a set value, it controls the second positive charging relay to close and controls the second pre-charge relay to open, so as to make the electrical connection between the power battery and the PDU conduct, forming the main charging circuit of the power battery.

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

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

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

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

[0016] Preferably, it also includes: 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 terminal of the power conversion unit in the charging pile and the positive terminal of the charging plug of the charging pile.

[0018] The third charging negative relay is connected in series between the negative output terminal 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 connected to the control terminal signals of the third positive charging relay and the third negative charging relay respectively, and controls the third positive charging relay and the third negative charging relay to close after the vehicle has completed charging preparation, so as to conduct the electrical connection between the charging pile and the power battery.

[0020] Preferably, both the electrical socket and the charging plug are provided with corresponding communication connection terminals. The charging pile controller is signal-connected to the communication connection terminal in the charging plug, and the 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 vehicle controller is established.

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

[0022] After the charging plug is connected to the charging socket, the charging station and the electric vehicle are respectively tested for insulation.

[0023] When the insulation test of the charging pile is successful, the third positive charging relay and the third negative charging relay are closed to put the charging pile into a charging ready state.

[0024] When the vehicle side has no problems with insulation testing, it first controls the pre-charge circuit in the battery pack to pre-charge, and after the pre-charge is completed, it controls the main charging circuit of the power battery to be turned on.

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

[0026] Preferred options also include:

[0027] When both the main charging circuit of the power battery and the main charging circuit of the PDU are in the conduction state, a vehicle charging ready signal is sent.

[0028] Once both the charging station and the vehicle are in a charging-ready state, the charging control of the charging station and the vehicle is performed via PP and CP signals.

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

[0030] First, control the second pre-charge relay and the second negative charging relay to close, so that the pre-charge circuit in the battery pack is connected to perform pre-charging;

[0031] After the voltage difference across 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 opened, so that the main charging circuit of the power battery is turned on.

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

[0033] First, control the first pre-charge relay and the first charging negative relay to close, so that the PDU pre-charge circuit is turned on for pre-charging;

[0034] After the voltage difference across the first positive charging relay is less than the set value, the first positive charging relay is closed and the first pre-charge relay is opened, so that the PDU main charging circuit is turned on.

[0035] This invention provides a charging control system and method for electric vehicles. Pre-charge relays are set at both ends of the charging positive relay of the main charging circuit of the PDU and the power battery to pre-charge the PDU and the power battery respectively. This solves the problem that the relays burn or stick when closed during the charging of existing electric vehicles, which can cause fire and high voltage safety hazards. It can avoid damage to the electrical components of the charging circuit, improve charging safety, and improve compatibility with charging piles. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

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

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

[0039] Figure 3 This is a flowchart of a charging control method provided in an embodiment of the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the embodiments of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and implementation methods.

[0041] The current charging of electric vehicles suffers from incompatibility with different charging stations due to varying charging sequences, potentially leading to safety hazards. This invention provides a charging control system and method for electric vehicles, addressing the problem of relays burning or sticking during charging, which can cause fires and high-voltage safety hazards. It prevents damage to electrical components in the charging circuit, improves charging safety, and enhances compatibility with charging stations.

[0042] like Figure 1As shown, a charging control system for an electric vehicle includes: a vehicle controller, a power distribution unit (PDU), a charging socket, a first pre-charge relay K8, a first positive charging relay K5, and a first negative charging relay K6. The first positive charging relay K5 is connected in series between the positive output terminal of the PDU and the positive terminal of the charging socket. The first negative charging relay K6 is connected in series between the negative output terminal of the PDU and the negative terminal of the charging socket. The first pre-charge relay K8 and the first positive charging relay K5 are connected in parallel. 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 terminals of the first pre-charge relay K8, the first positive charging relay K5, and the first negative charging relay K6. When the charging socket is plugged into the charging pile for charging, after the power battery charging and discharging circuit is connected, the vehicle controller first controls the first pre-charge relay K8 and the first charging negative relay K6 to close, so as to perform pre-charging through the PDU pre-charge circuit. When the voltage difference across the first charging positive relay K5 is less than a set value, the controller controls the first charging positive relay K5 to close and controls the first pre-charge relay K8 to open, forming the 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), also known as a high-voltage distribution box, incorporates a pre-charge circuit in the charging circuit between the PDU and the charging socket. This ensures that the voltage difference across the positive charging relay in the charging circuit is less than a set value before closure. The set value is the smaller value, meaning the voltages across the positive charging relay are similar, preventing arcing when the positive charging relay closes and thus avoiding safety hazards. Simultaneously, the relay closure between the charging station and the vehicle is controlled separately, eliminating restrictions on the timing of the vehicle's relay control of the charging station. This allows electric vehicles to access more charging stations on the market without damaging electrical components in the charging circuit, mitigating safety risks, or causing charging disruptions for customers.

[0044] The system also includes: a second pre-charge relay K7, a second positive charging relay K3, and a second negative charging relay K4. The second positive charging relay K3 is connected in series between the positive terminal of the power battery and the positive output terminal of the battery pack, and the second negative charging relay K4 is connected in series between the negative terminal of the power battery and the negative output terminal of the battery pack. The second pre-charge relay K7 and the second positive charging relay K3 are connected in parallel. The battery pack's BMS is connected to the control terminals of the second pre-charge relay K7, the second positive charging relay K3, and the second negative charging relay K4 respectively. When the power battery is charging or discharging, it first controls the second pre-charge relay K7 and the second negative charging relay K4 to close, so as to pre-charge through the battery pack pre-charge circuit. When the voltage difference across the second positive charging relay K3 is less than a set value, it controls the second positive charging relay K3 to close and controls the second pre-charge relay K7 to open, so that the electrical connection between the power battery and the PDU is established, forming the main charging circuit of the power battery.

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

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

[0047] Preferably, it further includes: a third positive charging relay K1 and a third negative charging relay K2; the third positive charging relay K1 is connected in series between the positive output terminal 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 K2 is connected in series between the negative output terminal 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 connected to the control terminal signals of the third positive charging relay K1 and the third negative charging relay K2 respectively, and controls the third positive charging relay K1 and the third negative charging relay K2 to close after the vehicle has completed charging preparation, so as to conduct the electrical connection between the charging pile and the power battery.

[0049] Furthermore, both the electrical socket and the charging plug are equipped with corresponding communication connection terminals. The charging pile controller is signal-connected to the communication connection terminal in the charging plug, and the 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 vehicle controller is established.

[0050] As can be seen, the present invention provides a charging control system for electric vehicles, which sets pre-charge relays at both ends of the charging positive relay of the main charging circuit of PDU and power battery to pre-charge control PDU and power battery respectively. This solves the problem that existing electric vehicles have relays that burn or stick when closed, causing fire and high voltage safety hazards. It can avoid damage to electrical components in the charging circuit, improve charging safety, and improve compatibility with charging piles.

[0051] like Figure 2 and Figure 3 As shown, the present invention also provides a charging control method for an electric vehicle, using the above-described 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 tested for insulation.

[0053] S2: When the insulation test of the charging pile is normal, close the third positive charging relay and the third negative charging relay to put the charging pile into the charging ready state.

[0054] S3: When there are no problems with the insulation test at the vehicle end, the pre-charge circuit in the battery pack is controlled to pre-charge, and after the pre-charge is completed, the main charging circuit of the power battery is controlled to be turned on.

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

[0056] The method also includes:

[0057] When both the main charging circuit of the power battery and the main charging circuit of the PDU are in operation, a vehicle charging ready signal is sent.

[0058] Once both the charging station and the vehicle are in a charging-ready state, the charging control of the charging station and the vehicle is performed via PP and CP signals.

[0059] Furthermore, the step of first controlling the pre-charge circuit within the battery pack to perform pre-charging, and then controlling the main charging circuit of the power battery to be turned on after the pre-charging is completed, includes:

[0060] First, the second pre-charge relay and the second negative charging relay are closed to activate the pre-charge circuit within the battery pack for pre-charging. Then, once the voltage difference across the second positive charging relay is less than a set value, the second positive charging relay is closed and the second pre-charge relay is opened, activating the main charging circuit of the power battery.

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

[0062] First, control the first pre-charge relay and the first negative charging relay to close, so that the PDU pre-charge circuit is turned on for pre-charging. After the voltage difference across the first positive charging relay is less than a set value, close the first positive charging relay and open the first pre-charge relay, so that the PDU main charging circuit is turned on.

[0063] In practical applications, when an electric vehicle needs charging, the charging plug on the charging station is inserted into the charging socket of the electric vehicle. After the insulation test between the charging station and the electric vehicle is successful, the subsequent charging actions begin: First, the electric vehicle closes the K4 main negative relay and the K7 pre-charge relay in the battery pack; second, after pre-charging, the K3 main positive relay closes and the K7 pre-charge relay opens; third, the K6 charging negative relay and the K8 pre-charge relay in the PDU close; fourth, the K5 charging positive relay in the PDU closes and the K8 pre-charge relay opens; fifth, the K2 negative relay in the charging station closes; sixth, the K1 positive relay in the charging station closes; and seventh, charging begins. The closing sequence of the K1 positive relay and the K2 negative relay in the charging station does not depend on the closing sequence of the relays in the electric vehicle and can close at any time. This allows the electric vehicle to cover more charging stations on the market without causing damage to electrical components in the charging circuit or safety risks, and without causing customers the inconvenience of being unable to charge.

[0064] As can be seen, the present invention provides a charging control method for electric vehicles, which sets pre-charge relays at both ends of the charging positive relays of the main charging circuit of the PDU and the power battery, and performs pre-charge control on the PDU and the power battery respectively. This solves the problem that the relays burn or stick when closed during the charging of existing electric vehicles, causing fire and high voltage safety hazards. It can avoid damage to the electrical components of the charging circuit, improve charging safety, and improve compatibility with charging piles.

[0065] The structure, features, and effects of the present invention have been described in detail above with reference to the embodiments shown in the figures. The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall be within the protection scope of the present invention as long as they do not exceed the spirit covered by the specification and figures.

Claims

1. A charging control system for an electric vehicle, characterized in that, include: Vehicle controller, PDU, charging socket, first pre-charge relay, first positive charging relay, first negative charging relay, second pre-charge relay, second positive charging relay and second negative charging relay; A pre-charge circuit is set in the charging circuit between the PDU and the charging socket so that the voltage difference across the positive charging relay in the charging circuit is less than a set value before closing; at the same time, the relay closing between the charging pile and the vehicle is controlled separately so that the timing of the vehicle's relay control of the charging pile is not restricted. The first positive charging relay is connected in series between the positive output terminal of the PDU and the positive terminal of the charging socket, the first negative charging relay is connected in series between the negative output terminal of the PDU and the negative terminal of the charging socket, and the first pre-charge relay is connected in parallel with the first positive charging relay. The vehicle controller is connected to the PDU via signal, the PDU is electrically connected to the vehicle battery pack, and the vehicle controller is connected to the control terminal signals of the first pre-charge relay, the first positive charging relay, and the first negative charging relay, respectively. When the charging socket is plugged into the charging pile for charging, after the power battery charging and discharging circuit is connected, the vehicle controller first controls the first pre-charge relay and the first charging negative relay to close, so as to pre-charge through the PDU pre-charge circuit. When the voltages at both ends of the first charging positive relay are equal, the controller controls the first charging relay to close and controls the first pre-charge relay to open, forming the PDU main charging circuit so that the charging pile can charge the power battery in the battery pack. The second positive charging relay is connected in series between the positive terminal of the power battery and the positive output terminal of the battery pack, the second negative charging relay is connected in series between the negative terminal of the power battery and the negative output terminal of the battery pack, and the second pre-charge relay is connected in parallel with the second positive charging relay. The BMS of the battery pack is connected to the control terminals of the second pre-charge relay, the second positive charging relay, and the second negative charging relay, respectively. When the power battery is charging or discharging, it first controls the second pre-charge relay and the second negative charging relay to close, so as to pre-charge through the battery pack pre-charge circuit. When the voltage difference across the second positive charging relay is less than a set value, it controls the second charging relay to close and controls the second pre-charge relay to open, so as to make the electrical connection between the power battery and the PDU conduct, forming the main charging circuit of the power battery.

2. The charging control system for electric vehicles according to claim 1, characterized in that, Also includes: First pre-charge resistor; The first pre-charge resistor is connected in series with the first pre-charge relay and then in parallel with the first positive charging relay.

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

4. The charging control system for electric vehicles according to claim 3, characterized in that, Also includes: The third charging positive relay and the third charging negative relay; The third charging positive relay is connected in series between the positive output terminal 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 is connected in series between the negative output terminal 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 connected to the control terminal signals of the third positive charging relay and the third negative charging relay respectively, and controls the third positive charging relay and the third negative charging relay to close after the vehicle has completed charging preparation, so as to conduct the electrical connection between the charging pile and the power battery.

5. The charging control system for an electric vehicle according to claim 4, characterized in that, Both the charging socket and the charging plug are equipped with corresponding communication connection terminals. The charging pile controller is signal-connected to the communication connection terminal in the charging plug, and the 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 vehicle controller is established.

6. A charging control method for an electric vehicle, using the charging control system described in claim 5, characterized in that, include: After the charging plug is connected to the charging socket, the charging station and the electric vehicle are respectively tested for insulation. When the insulation test of the charging pile is successful, the third positive charging relay and the third negative charging relay are closed to put the charging pile into a charging ready state. When the vehicle side has no problems with insulation testing, it first controls the pre-charge circuit in the battery pack to pre-charge, and after the pre-charge is completed, it controls the main charging circuit of the power battery to be turned on. After the main charging circuit is turned on, the PDU pre-charging circuit is controlled to perform pre-charging, and after the pre-charging is completed, the PDU main charging circuit is turned on.

7. The charging control method for an electric vehicle according to claim 6, characterized in that, Also includes: When both the main charging circuit of the power battery and the main charging circuit of the PDU are in the conduction state, a vehicle charging ready signal is sent. Once both the charging station and the vehicle are in a charging-ready state, the charging control of the charging station and the vehicle is performed via PP and CP signals.

8. The charging control method for an electric vehicle according to claim 7, characterized in that, The first step of controlling the pre-charging circuit within the battery pack to perform pre-charging, and then controlling the main charging circuit of the power battery to be turned on after the pre-charging is completed, includes: First, control the second pre-charge relay and the second negative charging relay to close, so that the pre-charge circuit in the battery pack is connected to perform pre-charging; After the voltage difference across 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 opened, so that the main charging circuit of the power battery is turned on.

9. The charging control method for an electric vehicle according to claim 8, characterized in that, The first step of controlling the PDU pre-charging circuit to perform pre-charging, and then controlling the PDU main charging circuit to turn on after pre-charging is completed, includes: First, control the first pre-charge relay and the first charging negative relay to close, so that the PDU pre-charge circuit is turned on for pre-charging; After the voltage difference across the first positive charging relay is less than the set value, the first positive charging relay is closed and the first pre-charge relay is opened, so that the PDU main charging circuit is turned on.

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