Power battery power supply circuit, power battery system and electric vehicle

Abstract

The utility model discloses a power battery power supply circuit, a power battery system and an electric vehicle, in the power battery power supply circuit, a battery positive electrode port is connected with a positive electrode of a power battery, a battery negative electrode port is connected with a negative electrode of the power battery, and the battery positive electrode port is connected with a load positive electrode port through a main positive relay; the battery negative electrode port is connected with the load negative electrode port through the main positive relay, the battery negative electrode port is connected with the load negative electrode port through the main negative relay, at least one of the main positive relay and the main negative relay is connected with a switching tube in parallel, the driving circuit is connected with the control end of the switching tube, and the driving circuit is connected with the BMS. Pre-charging can be carried out through the switch tube during pre-charging, noise generated when a pre-charging relay is used for pre-charging is avoided, the two ends of the relay can be in short circuit through the switch tube during power-off, so that voltages at the two ends of the relay are equal, no arc discharge is generated when the relay is disconnected, and the service life of the relay is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of power battery power supply, and in particular to a power battery power supply circuit, a power battery system and an electric vehicle. Background Art

[0002] like Figure 1 As shown, in electric vehicles such as electric cars, electric aircraft, and electric ships, in the power supply circuit of the power battery to the load ports HV+ and HV-, a main positive relay RL1 is provided on the positive high-voltage bus, and a main negative relay RL2 is provided on the negative high-voltage bus. In order to avoid the impact of excessive current on the load port when power is turned on, a pre-charge resistor R1 and a pre-charge relay RL3 are connected in series in parallel at both ends of the main positive relay RL1.

[0003] When the power battery powers on the load ports HV+ and HV-, it first closes the pre-charge relay RL3 to pre-charge the high-voltage bus, then controls the main positive relay RL1 and the main negative relay RL2 to close and officially supply power. When power is turned off, the main positive relay RL1 and the main negative relay RL2 are directly disconnected.

[0004] During the power-on process, the above-mentioned power supply circuit needs to first close the pre-charging relay RL3 for pre-charging, and disconnect the pre-charging relay RL3 after the pre-charging is completed. The action of the pre-charging relay RL3 during power-on generates noise, affecting the user's experience of using the electric vehicle. In addition, when the power is turned off, when the relay is disconnected, the voltage difference between the two ends is too large, which easily generates arcing, reducing the service life of the relay. Utility Model Content

[0005] The purpose of the present invention is to provide a power battery power supply circuit, a power battery system, and an electric vehicle to solve the problems of noise generated by the operation of the pre-charge relay in the existing power battery power supply circuit and reduced service life caused by arcing of the relay. The embodiments of the present invention adopt the following technical solutions:

[0006] In a first aspect, a power battery power supply circuit is provided, comprising a battery positive terminal connected to the positive electrode of the power battery, a battery negative terminal connected to the negative electrode of the power battery, a main positive relay, a main negative relay, a switch tube, a drive circuit connected to a BMS, and a load positive terminal and a load negative terminal connected to a load;

[0007] The positive electrode port of the battery is connected to the positive electrode port of the load through a main positive relay, and the negative electrode port of the battery is connected to the negative electrode port of the load through the main negative relay. At least one of the main positive relay and the main negative relay is connected in parallel with the switching tube, and the driving circuit is connected to the control end of the switching tube.

[0008] Optionally, the switch tube includes a main positive switch tube, the main positive switch tube is connected in parallel to both ends of the main positive relay, and the control end of the main positive switch tube is connected to the drive circuit.

[0009] Optionally, a main negative switch tube is further included, wherein the main negative switch tube is connected in parallel to both ends of the main negative relay, and the control end of the main negative switch tube is connected to the drive circuit.

[0010] Optionally, a current measuring module is further included, for detecting the current flowing through the switch tube;

[0011] and / or;

[0012] It also includes a temperature detection module for detecting the temperature of the switch tube.

[0013] Optionally, the current measurement module is configured to be connected to the BMS, and is configured to receive a control signal from the BMS to detect the current flowing through the switch tube, and transmit the detected current to the BMS;

[0014] The temperature detection module is configured to be connected to the BMS, and is used to receive a control signal from the BMS to detect the temperature of the switch tube, and transmit the detected temperature to the BMS.

[0015] Optionally, a charging port is further included, wherein the switch tube includes a main positive switch tube, and the main positive switch tube is connected in parallel to both ends of the main positive relay. The positive terminal of the charging port is connected to the positive terminal of the battery through the parallel main positive relay and the main positive switch tube, and the negative terminal of the charging port is connected to the negative terminal of the battery through the main negative relay.

[0016] and / or;

[0017] It also includes a main negative switch tube, which is connected in parallel at both ends of the main negative relay. The negative end of the charging port is connected to the negative port of the battery through the parallel main negative relay and the main negative switch tube, and the positive end of the charging port is connected to the positive port of the battery through the main positive relay.

[0018] In a second aspect, a power battery system is provided, comprising a power battery, a BMS, and the power battery power supply circuit described in any one of the first aspects, wherein the positive electrode of the power battery is connected to the battery positive terminal in the power battery power supply circuit, the negative electrode of the power battery is connected to the battery negative terminal in the power battery power supply circuit, and the BMS is connected to the drive circuit in the power battery power supply circuit.

[0019] Optionally, the number of the power batteries is more than two.

[0020] In a third aspect, an electric vehicle is provided, comprising a load and the power battery system according to any one of the second aspects, wherein the load is connected to a load positive port and a load negative port of a power battery power supply circuit in the power battery system.

[0021] Optionally, the load includes a low voltage battery.

[0022] The power battery power supply circuit of this embodiment includes a battery positive port connected to the positive electrode of the power battery, a battery negative port connected to the negative electrode of the power battery, a main positive relay, a main negative relay, a switch tube, a drive circuit connected to the BMS, and a load positive port and a load negative port connected to the load. The battery positive port is connected to the load positive port through the main positive relay, and the battery negative port is connected to the load negative port through the main negative relay. At least one of the main positive relay and the main negative relay is connected in parallel with a switch tube, and the drive circuit is connected to the control end of the switch tube. By connecting at least one of the main positive relay and the main negative relay in parallel with the switch tube, pre-charging can be performed through the switch tube during pre-charging, avoiding the noise generated by the action of the pre-charging relay during pre-charging, thereby improving the user experience. Moreover, by connecting the switch tube in parallel to the relay, the two ends of the relay can be short-circuited through the switch tube when the power is turned off, so that the voltages at the two ends of the relay are equal, and no arcing is generated when the relay is disconnected, thereby improving the service life of the relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 It is a schematic diagram of a power battery power supply circuit in the prior art.

[0025] Figure 2 This is a schematic diagram of a power battery power supply circuit in which a main positive relay is connected in parallel with a main positive switch tube in an embodiment of the present utility model.

[0026] Figure 3 This is a schematic diagram of a power battery power supply circuit in which a main negative relay is connected in parallel with a main negative switch tube in an embodiment of the present utility model.

[0027] Figure 4 This is a schematic diagram of a power battery power supply circuit in which both the main positive relay and the main negative relay are connected in parallel with switch tubes according to an embodiment of the present utility model.

[0028] Figure 5 This is a schematic diagram of a power battery power supply circuit with a charging port set when the main positive relay is connected in parallel with the main positive switch tube.

[0029] Figure 6 This is a schematic diagram of a power battery power supply circuit with a charging port when the main negative relay is connected in parallel with the main negative switch tube.

[0030] Figure 7 This is a schematic diagram of a power battery power supply circuit with a charging port when both the main positive relay and the main negative relay are connected to switching tubes in parallel. DETAILED DESCRIPTION

[0031] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved more clearly, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0032] In the description of this utility model, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0033] Figure 2 This is a schematic diagram of a power battery power supply circuit of an embodiment of the present invention. The power battery power supply circuit is used to connect the power battery BAT and the load port (HV+, HV-) so that the power battery BAT supplies power to the load port (HV+, HV-) through the power battery power supply circuit, so as to provide power to the load connected to the load port through the load port (HV+, HV-).

[0034] like Figure 2 As shown, the power battery power supply circuit of this embodiment includes a battery positive terminal BAT+ connected to the positive electrode of the power battery BAT, a battery negative terminal BAT- connected to the negative electrode of the power battery BAT, a main positive relay RL1, a main negative relay RL2, a switch tube, a drive circuit connected to the BMS, and a load positive terminal HV+ and a load negative terminal HV- connected to the load.

[0035] Among them, the power battery BAT can be a rechargeable battery installed in electric vehicles such as electric vehicles, electric ships, and electric aircraft. The battery positive terminal BAT+ and the battery negative terminal BAT- can be ports in the power battery power supply circuit that can be connected to the positive and negative electrodes of the power battery BAT, for example, they can be various forms of electrical connectors. The load positive terminal HV+ and the load negative terminal HV- can be ports connected to the load on the electric vehicle. The switching tube can be a semiconductor electronic switching tube, for example, it can be one of a triode, a MOSFET, and an IGBT.

[0036] The driving circuit may be a circuit that drives the switch tube to be turned on or off. For example, the driving circuit may be a circuit that generates a pulse signal to drive the switch tube to be turned on or off under the control of the BMS. The BMS may be a management system for the power battery.

[0037] In this embodiment, the battery positive terminal BAT+ is connected to the load positive terminal HV+ through the main positive relay RL1, and the battery negative terminal BAT- is connected to the load negative terminal HV- through the main negative relay RL2. At least one of the main positive relay RL1 and the main negative relay RL2 is connected in parallel with a switching tube, and the drive circuit is connected to the control end of the switching tube.

[0038] In an alternative embodiment, if Figure 2 As shown, the switch tube can be the main positive switch tube Q1, which is connected in parallel at both ends of the main positive relay RL1. The control end of the main positive switch tube Q1 is connected to the drive circuit. Taking the power battery BAT powering the electric vehicle through the power battery power supply circuit as an example, during the vehicle power-on stage, the main negative relay RL2 is closed first, and the main positive relay RL1 is disconnected. Then, a control signal is sent to the drive circuit through the BMS, and the main positive switch tube Q1 is intermittently turned on through the drive circuit, so that the power battery BAT first passes a smaller current to the load port (HV+ , HV-) are powered on for pre-charging. After the pre-charging is completed, if the current required by the vehicle load is less than the threshold value (such as before the electric vehicle starts driving), the main positive relay RL1 is kept disconnected, and the driving voltage of the main positive switch tube Q1 is controlled by the drive circuit to be in a high level state (duty cycle is 1), so that the main positive switch tube Q1 remains on, and the power battery BAT supplies power to the load port (HV+, HV-) through the main positive switch tube Q1. In the pre-charging stage and low current power supply conditions, the main positive relay RL1 does not need to be closed, which avoids the action of the main positive relay RL1. Figure 1 The power supply circuit in the circuit reduces the number of relays in action, reduces the noise generated by the relay action, and can reduce the number of actions of the main positive relay RL1, thereby increasing the service life of the main positive relay RL1.

[0039] When the output power of the power battery needs to be increased while the vehicle is running, the BMS can output a signal to the drive circuit to control the main positive switch tube Q1 to be cut off, and the main positive relay RL1 to be closed. The power battery BAT is powered by the main positive relay RL1 to avoid excessive output current of the power battery BAT and damage to the main positive switch tube Q1 when the vehicle is running. When the vehicle is powered off, the BMS outputs a signal to the drive circuit to control the main positive switch tube Q1 to be turned on, and the voltages at both ends of the main positive relay RL1 are equal. When the main positive relay RL1 is controlled to be disconnected, no arcing is generated. Then, the drive circuit controls the main positive switch tube Q1 to be cut off, and controls the main negative relay RL2 to be disconnected, thereby completing the power-off of the vehicle. This avoids arcing when the main positive relay RL1 is disconnected when the vehicle is powered off, thereby improving the service life of the main positive relay RL1.

[0040] In another alternative embodiment, Figure 3 As shown, the switch tube can be the main negative switch tube Q2, which is connected in parallel at both ends of the main negative relay RL2. The control end of the main negative switch tube Q2 is connected to the drive circuit. Still taking the power battery BAT powering the electric vehicle through the power battery power supply circuit as an example, in the vehicle power-on stage, when the power battery needs to power the vehicle, the main positive relay RL1 can be closed first, and the main negative relay RL2 can be disconnected. Then, the control signal is output to the drive circuit through the BMS. The drive circuit controls the main negative switch tube Q2 to be intermittently turned on, so that the power battery BAT first passes a smaller current to the negative relay. The load port is powered on for pre-charging. After the pre-charging is completed, if the current required by the vehicle load is less than the threshold (such as before the electric vehicle starts driving), the main negative relay RL2 is kept disconnected, and the driving voltage of the main negative switch tube Q2 is controlled by the drive circuit to be in a high level state (duty cycle is 1), so that the main negative switch tube Q2 remains on, and the power battery BAT supplies power to the load port (HV+, HV-) through the main positive relay RL1 and the main negative switch tube Q2. In the power-on pre-charging stage and low current power supply conditions, there is no need to close the main negative relay RL2, which avoids the action of the main negative relay RL2. Figure 1 The power supply circuit of the prior art reduces the number of relays in operation, reduces the noise generated by the relay operation, reduces the number of operations of the main negative relay RL2, and increases the service life of the main negative relay RL2.

[0041] When the output power of the power battery needs to be increased while the vehicle is running, the BMS can output a signal to the drive circuit to control the main negative switch tube Q2 to be cut off, and the main negative relay RL2 to be closed. The power battery BAT is powered by the main positive relay RL1 and the main negative relay RL2 to avoid excessive output current of the power battery BAT and damage to the main negative switch tube Q2 when the vehicle is running. When the vehicle is powered off, the BMS outputs a signal to the drive circuit to control the main negative switch tube Q2 to remain on, and the voltages at both ends of the main negative relay RL2 are equal. No arcing is generated when the main negative relay RL2 is controlled to be disconnected. Then, the drive circuit controls the main negative switch tube Q2 to be cut off, and controls the main positive relay RL1 to be disconnected, completing the power-off of the vehicle. This avoids arcing when the main negative relay RL2 is disconnected when the vehicle is powered off, thereby improving the service life of the main negative relay RL2.

[0042] In yet another embodiment, Figure 4 As shown, the switch tube may include a main positive switch tube Q1 and a main negative switch tube Q2. The main positive switch tube Q1 is connected in parallel at both ends of the main positive relay RL1, and the main negative switch tube Q2 is connected in parallel at both ends of the main negative relay RL2. Still taking the power battery BAT powering the electric vehicle through the power battery power supply circuit as an example, in the vehicle power-on stage, when the power battery needs to power the vehicle, the main positive relay RL1 and the main negative relay RL2 are controlled to be disconnected, and then a control signal is sent to the drive circuit through the BMS, and the main positive switch tube Q1 and the main negative switch tube Q2 are controlled to be intermittently turned on through the drive circuit, so that the power battery BAT first pre-charges the load port with a small current, and waits for the power battery BAT to be powered on. After the pre-charging is completed, if the current required by the vehicle load is less than the threshold value (such as before the electric vehicle starts driving), the main positive relay RL1 and the main negative relay RL2 are kept disconnected, and the driving voltage of the main positive switch tube Q1 and the main negative switch tube Q2 is controlled by the driving circuit to be in a high level state (duty cycle is 1), so that the main positive switch tube Q1 and the main negative switch tube Q2 remain turned on, and the power battery BAT supplies power to the load port (HV+, HV-) through the main positive switch tube Q1 and the main negative switch tube Q2. In the power-on pre-charging stage and low current power supply conditions, there is no need to close the main positive relay RL1 and the main negative relay RL2, which avoids the action of the main positive relay RL1 and the main negative relay RL2. Figure 1 In the power supply circuit of the existing technology, no relay action is required under power-on and low current power supply conditions, thereby avoiding the noise generated by the relay action, and reducing the number of actions of the main positive relay RL1 and the main negative relay RL2, thereby increasing the service life of the main positive relay RL1 and the main negative relay RL2.

[0043] When the vehicle's power output needs to be increased during driving, the BMS can output a signal to the drive circuit to turn off the main positive switch Q1 and the main negative switch Q2, and close the main positive relay RL1 and the main negative relay RL2. The power battery BAT is powered by the main positive relay RL1 and the main negative relay RL2, preventing damage to the main positive switch Q1 and the main negative switch Q2 due to excessive output current from the power battery BAT while the vehicle is running. When the vehicle is powered off, the BMS outputs a signal to the drive circuit to turn on the main positive switch Q1 and the main negative switch Q2, equalizing the voltages across the main positive relay RL1 and the main negative relay RL2. This prevents arcing when the main positive relay RL1 and the main negative relay RL2 are disconnected, and the drive circuit then turns off the main positive switch Q1 and the main negative switch Q2 to complete the vehicle power-off process. This prevents arcing when the main positive relay RL1 and the main negative relay RL2 are disconnected during vehicle power-off, thereby extending the service life of the main positive relay RL1 and the main negative relay RL2.

[0044] like Figure 4 As shown, in one embodiment, it also includes a current measuring module A, which is used to detect the current flowing through the switch tube, such as Figure 4 As shown, the current measurement module A can be set on the positive busbar connected to the power battery BAT. Of course, it can also be set on the branch where the switch tube is located. The current detection module A is configured to be connected to the BMS and is used to detect the current flowing through the switch tube when receiving the control signal of the BMS and transmit the detected current to the BMS. For example, Figure 4 As shown, when the power battery BAT supplies power to the load ports (HV+, HV-) through the main positive switch tube Q1 and the main negative switch tube Q2, the current detected by the current detection module A is the current flowing through the main positive switch tube Q1 and the main negative switch tube Q2. After the current detected by the current detection module A is transmitted to the BMS, the BMS controls the main positive switch tube Q1 and the main negative switch tube Q2 to be turned off and stop working through the drive circuit when the current is greater than the threshold, and controls the main positive relay RL1 and the main negative relay RL2 to be closed, so that the power battery BAT switches to supply power through the main positive relay RL1 and the main negative relay RL2, preventing excessive current from damaging the main positive switch tube Q1 and the main negative switch tube Q2, thereby achieving overcurrent protection for the main positive switch tube Q1 and the main negative switch tube Q2.

[0045] In an optional embodiment, a temperature detection module may be further included, which is configured to be connected to the BMS and used to detect the temperature of the switch tube. For example, the temperature detection module can detect the temperature of the switch tube when receiving the control signal of the BMS and transmit the detected temperature to the BMS. Figure 4As shown, when the power battery BAT supplies power to the load ports (HV+, HV-) through the main positive switch tube Q1 and the main negative switch tube Q2, the temperature detection module detects the temperatures of the main positive switch tube Q1 and the main negative switch tube Q2 and transmits the detected temperatures to the BMS. When the temperature is greater than a threshold, the BMS controls the main positive switch tube Q1 and the main negative switch tube Q2 to be turned off and stops working, and controls the main positive relay RL1 and the main negative relay RL2 to be closed, so that the power battery BAT switches to supplying power through the main positive relay RL1 and the main negative relay RL2, avoiding damage to the main positive switch tube Q1 and the main negative switch tube Q2 due to excessive temperature, thereby achieving overtemperature protection for the main positive switch tube Q1 and the main negative switch tube Q2.

[0046] The power battery power supply circuit of this embodiment may further include a charging port for charging the power battery through the power battery power supply circuit after connecting a charging device through the charging port. Figure 5 As shown, in one embodiment, the switch tube may be a main positive switch tube Q1, which is connected in parallel at both ends of a main positive relay RL1. The positive terminal D+ of the charging port is connected to the battery positive terminal BAT+ through the parallel main positive relay RL1 and the main positive switch tube Q1, and the negative terminal D- of the charging port is connected to the battery negative terminal BAT- through the main negative relay RL2. When the BMS interacts with a charging device connected to the charging port and performs slow charging with a low charging current, the BMS can control the main positive switch tube Q1 and the main negative relay RL2 to close through a drive circuit, so that the charging device charges the power battery BAT through the main positive switch tube Q1 and the main negative relay RL2, without closing the main positive relay RL1. This avoids noise generated by the operation of the main positive relay RL1, reduces the number of operations of the main positive relay RL1, and increases the service life of the main positive relay RL1. If the BMS interacts with a charging device connected to the charging port and performs fast charging with a high charging current, the power battery BAT can be charged directly through the main positive relay RL1 and the main negative relay RL2.

[0047] like Figure 6As shown, when the switch is the main negative switch Q2, it is connected in parallel across the main negative relay RL2. The negative terminal D- of the charging port is connected to the negative terminal BAT- of the battery through the parallel main negative relay RL2 and the main negative switch Q2. The positive terminal D+ of the charging port is connected to the positive terminal BAT+ of the battery through the main positive relay RL1. When the BMS interacts with a charging device connected to the charging port and performs slow charging at a low current, the BMS can control the main negative switch Q2 and the main positive relay RL1 to close through the drive circuit, allowing the charging device to charge the power battery BAT through the main negative switch Q2 and the main positive relay RL1. This eliminates the need to close the main negative relay RL2, avoids noise generated by the main negative relay RL2, reduces the number of main negative relay RL2 actuations, and improves the service life of the main negative relay RL2. If the BMS interacts with a charging device connected to the charging port and performs fast charging at a high current, the power battery BAT can be charged directly through the main positive relay RL1 and the main negative relay RL2.

[0048] like Figure 7 As shown, when the switching tube includes a main positive switching tube Q1 and a main negative switching tube Q2, the positive terminal D+ of the charging port is connected to the positive terminal BAT+ of the battery through the main positive relay RL1 and the main positive switching tube Q1 connected in parallel, and the negative terminal D- of the charging port is connected to the negative terminal BAT- of the battery through the main negative relay RL2 and the main negative switching tube Q2 connected in parallel. When the BMS interacts with a charging device connected to the charging port and performs slow charging when the charging current is low, the BMS can control the main positive switching tube Q1 and the main negative switching tube Q2 to close through the driving circuit, so that the charging device charges the power battery BAT through the main positive switching tube Q1 and the main negative switching tube Q2, without closing the main positive relay RL1 and the main negative relay RL2. This avoids noise generated by the operation of the main positive relay RL1 and the main negative relay RL2, reduces the number of operations of the main positive relay RL1 and the main negative relay RL2, and improves the service life of the main positive relay RL1 and the main negative relay RL2. If the BMS interacts with the charging device connected to the charging port and performs fast charging with a large charging current, the power battery BAT can be charged directly through the main positive relay RL1 and the main negative relay RL2.

[0049] This embodiment also provides a power battery system, which includes a power battery, a BMS and a power battery power supply circuit, wherein the power battery power supply circuit can be the power battery system of this embodiment. Figure 2-Figure 7 Any of the power battery power supply circuits shown.

[0050] like Figure 7As shown, in the power battery system, the positive electrode of the power battery BAT is connected to the battery positive terminal BAT+ in the power battery power supply circuit, the negative electrode of the power battery is connected to the battery negative terminal BAT- in the power battery power supply circuit, and the BMS is connected to the drive circuit in the power battery power supply circuit. The number of power batteries BAT can be one or more, for example, two or three. This embodiment does not limit the number of power batteries BAT.

[0051] This embodiment also provides an electric vehicle, which includes a load and a power battery system of an embodiment of the utility model, wherein the load is connected to the load positive port and the load negative port of the power battery power supply circuit in the power battery system. Exemplarily, the electric vehicle can be an electric car, an electric aircraft, an electric ship, etc. The load can include an electric motor on the electric vehicle, and can also include a low-voltage battery, which is connected to the load port. The low-voltage battery can power the low-voltage equipment on the electric vehicle, and of course can also include other low-voltage or high-voltage electrical equipment.

[0052] In one example, on an electric vehicle, if the electric vehicle is in a dormant state and detects that the power level of the low-voltage battery is less than a threshold, the controller of the electric vehicle can send a power-on command to the BMS. After receiving the power-on command, the BMS can drive the switch tube to close through the drive circuit to Figure 7 Taking the circuit in as an example, the main positive switch tube Q1 and the main negative switch tube Q2 can be controlled to be turned on, and the main positive relay RL1 and the main negative relay RL2 can be controlled to be turned off. The power battery BAT supplies power to the low-voltage battery connected to the load port (HV+, HV-) through the main positive switch tube Q1 and the main negative switch tube Q2. There is no need to close the main positive relay RL1 and the main negative relay RL2. When the electric vehicle is dormant and the low-voltage battery is charged, the noise generated by the operation of the main positive relay RL1 and the main negative relay RL2 can be avoided, and the number of operations of the main positive relay RL1 and the main negative relay RL2 can be reduced, thereby improving the service life of the main positive relay RL1 and the main negative relay RL2.

[0053] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the purpose of clarifying the device. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0054] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and should not be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will be able to devise other specific implementations of the present invention without inventive effort, and such implementations will fall within the scope of protection of the present invention.

Claims

1. A power battery power supply circuit, characterized in that: It includes a battery positive terminal connected to the positive electrode of the power battery, a battery negative terminal connected to the negative electrode of the power battery, a main positive relay, a main negative relay, a switch tube, a drive circuit connected to the BMS, and a load positive terminal and a load negative terminal connected to the load; The positive electrode port of the battery is connected to the positive electrode port of the load through a main positive relay, and the negative electrode port of the battery is connected to the negative electrode port of the load through the main negative relay. At least one of the main positive relay and the main negative relay is connected in parallel with the switching tube, and the driving circuit is connected to the control end of the switching tube.

2. The power battery power supply circuit according to claim 1, characterized in that: The switch tube includes a main positive switch tube, the main positive switch tube is connected in parallel to both ends of the main positive relay, and the control end of the main positive switch tube is connected to the drive circuit.

3. The power battery power supply circuit according to claim 2, characterized in that: It also includes a main negative switch tube, which is connected in parallel to both ends of the main negative relay, and the control end of the main negative switch tube is connected to the drive circuit.

4. The power battery power supply circuit according to claim 1, characterized in that: It also includes a current measurement module for detecting the current flowing through the switch tube; and / or, It also includes a temperature detection module for detecting the temperature of the switch tube.

5. The power battery power supply circuit according to claim 4, characterized in that: The current measurement module is configured to be connected to the BMS, and is used to receive a control signal from the BMS to detect the current flowing through the switch tube, and transmit the detected current to the BMS; The temperature detection module is configured to be connected to the BMS, and is used to receive a control signal from the BMS to detect the temperature of the switch tube, and transmit the detected temperature to the BMS.

6. The power battery power supply circuit according to claim 1, characterized in that: The battery also includes a charging port, wherein the switch tube includes a main positive switch tube, and the main positive switch tube is connected in parallel to both ends of the main positive relay. The positive end of the charging port is connected to the positive terminal of the battery through the parallel main positive relay and the main positive switch tube, and the negative end of the charging port is connected to the negative terminal of the battery through the main negative relay. and / or, It also includes a main negative switch tube, which is connected in parallel at both ends of the main negative relay. The negative end of the charging port is connected to the negative port of the battery through the parallel main negative relay and the main negative switch tube, and the positive end of the charging port is connected to the positive port of the battery through the main positive relay.

7. A power battery system, characterized in that: It comprises a power battery, a BMS and the power battery power supply circuit according to any one of claims 1 to 6, wherein the positive electrode of the power battery is connected to the battery positive terminal in the power battery power supply circuit, the negative electrode of the power battery is connected to the battery negative terminal in the power battery power supply circuit, and the BMS is connected to the drive circuit in the power battery power supply circuit.

8. The power battery system according to claim 7, characterized in that: The number of the power batteries is more than two.

9. An electric vehicle, characterized in that: The power battery system comprises a load and the power battery system according to claim 7 or 8, wherein the load is connected to a load positive electrode port and a load negative electrode port of a power battery power supply circuit in the power battery system.

10. The electric vehicle according to claim 9, characterized in that: The load includes a low-voltage battery.

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