Battery charging method and vehicle electrical system for controlling charging current based on temperature of battery
A battery charging control method applicable to a vehicle electrical system that includes a current control unit including a semiconductor device. Two ends of the current control unit are connected to a battery and a charging power supply, respectively. The method includes controlling, when a temperature of the battery is below a preset temperature, the current control unit to be in a first state in which the semiconductor device is reversely connected in a circuit, sending a first charging request including a first charging current required to heat the battery to the preset temperature, controlling, when the temperature of the battery reaches the preset temperature, the current control unit to be in a second state in which the semiconductor device is disconnected from the circuit or forwardly connected in the circuit, and sending a second charging request including a second charging current at which the battery is charged.
1. A battery charging control method applicable to a vehicle electrical system, wherein the vehicle electrical system comprises a battery heating module, and a current control unit that comprises a semiconductor device, a first relay, and a second relay, one end of the first relay being connected to a first end of a battery, another end of the first relay being connected to a first end of a charging power supply, one end of the semiconductor device being connected to the first end of the battery, another end of the semiconductor device being connected to one end of the second relay, another end of the second relay being connected to the first end of the charging power supply; and the battery heating module is connected in parallel with the battery and the current control unit, one end of the battery heating module being connected to the battery and the charging power supply, and the other end being connected to the current control unit and the charging power supply, the method comprising:
controlling, in response to a temperature of the battery being below a first preset temperature, the current control unit to be in a first state, wherein the charging power supply forms a loop with the battery heating module, and the charging power supply supplies power to the battery heating module to heat the battery; and the first state is a state in which the semiconductor device is reversely connected in a circuit, the first relay is turned off, the second relay is turned on, and the current control unit blocks a passage of current;
sending a first charging request to the charging power supply, wherein the first charging request comprises a first charging current, and the first charging current is a current required to heat the battery to the first preset temperature and entering the battery heating module;
controlling, in response to the temperature of the battery reaching the first preset temperature, the current control unit to be in a second state, wherein the second state is a state in which the semiconductor device is disconnected from the circuit or the semiconductor device is forwardly connected in the circuit, the first relay is turned on, the second relay is turned off, and the current control unit allows the passage of current; and
sending a second charging request to the charging power supply, wherein the second charging request comprises a second charging current at which the battery is charged.
2. The control method according to claim 1 , wherein controlling, in response to the temperature of the battery reaching the first preset temperature, the current control unit to be in the second state comprises:
sending the first charging request to the charging power supply in response to the temperature of the battery reaching the first preset temperature, wherein the first charging request comprises: the first charging current being 0.
3. The control method according to claim 1 , wherein:
the current control unit further comprises a bidirectional semiconductor device; and
controlling, in response to the temperature of the battery reaching the first preset temperature, the current control unit to be in the second state comprises:
controlling, in response to the temperature of the battery reaching the first preset temperature, the bidirectional semiconductor device to commutate, so that the bidirectional semiconductor device is forwardly connected in the circuit.
4. The control method according to claim 1 , wherein the semiconductor device comprises at least one of a diode, a silicon controlled rectifier, or a bidirectional insulated gate bipolar transistor (IGBT).
5. A vehicle electrical system, comprising:
a current control unit that comprises a semiconductor device, a first relay, and a second relay, one end of the first relay being connected to a first end of a battery, another end of the first relay being connected to a first end of a charging power supply, one end of the semiconductor device being connected to the first end of the battery, another end of the semiconductor device being connected to one end of the second relay, another end of the second relay being connected to the first end of the charging power supply;
a battery heating module, wherein the battery heating module is connected in parallel with the battery and the current control unit, one end of the battery heating module being connected to the battery and the charging power supply, and the other end being connected to the current control unit and the charging power supply;
a control module configured to:
control, in response to a temperature of the battery being below a first preset temperature, the current control unit to be in a first state, wherein the charging power supply forms a loop with the battery heating module, and the charging power supply supplies power to the battery heating module to heat the battery; and the first state is a state in which the semiconductor device is reversely connected in a circuit, the first relay is turned off, the second relay is turned on, and the current control unit blocks a passage of current; and
control, in response to the temperature of the battery reaching the first preset temperature, the current control unit to be in a second state, wherein the second state is a state in which the semiconductor device is disconnected from the circuit or the semiconductor device is forwardly connected in the circuit, the first relay is turned on, the second relay is turned off, and the current control unit allows the passage of current; and a communication module configured to:
send a first charging request to the charging power supply, wherein the first charging request comprises a first charging current, and the first charging current is a current required to heat the battery to the first preset temperature and entering the battery heating module; and
send a second charging request to the charging power supply, wherein the second charging request comprises a second charging current at which the battery is charged.
6. The system according to claim 5 , wherein the communication module is further configured to send the first charging request to the charging power supply in response to the temperature of the battery reaching the first preset temperature, wherein the first charging request comprises: the first charging current being 0.
7. A vehicle electrical system, comprising:
a battery;
a battery heating module; and
a current control unit that comprises a first relay, a second relay, and a semiconductor device, one end of the first relay being connected to a first end of the battery, another end of the first relay being connected to a first end of a charging power supply, one end of the semiconductor device being connected to the first end of the battery, another end of the semiconductor device being connected to one end of the second relay, another end of the second relay being connected to the first end of the charging power supply; wherein the battery heating module is connected in parallel with the battery and the current control unit, one end of the battery heating module being connected to the battery and the charging power supply, and the other end being connected to the current control unit and the charging power supply;
wherein the current control unit is configured to be:
in a first state in response to a temperature of the battery being below a first preset temperature, the first relay being turned off and the second relay being turned on in the first state, wherein the semiconductor device is reversely connected in a circuit and the current control unit blocks a passage of current, the charging power supply forms a loop with the battery heating module, and the charging power supply supplies power to the battery heating module to heat the battery; and
in a second state in response to the temperature of the battery reaching the first preset temperature, the first relay being turned on and the second relay being turned off in the second state, wherein the semiconductor device is disconnected from the circuit or the semiconductor device is forwardly connected in the circuit and the current control unit allows the passage of current.