BMS low-voltage power supply circuit and vehicle

Abstract

The utility model relates to a BMS low-voltage power supply circuit and a vehicle, and belongs to the technical field of BMS power supply. The BMS low-voltage power supply circuit comprises a battery pack power supply branch connected in parallel at two ends of a battery pack and an external low-voltage power supply branch connected in parallel at two ends of an external low-voltage power supply, the battery pack power supply branch is connected in series with a battery pack low-voltage power-on switch, and the external low-voltage power supply branch is connected in series with an external low-voltage power-on switch; the battery pack power supply branch and the external low-voltage power supply branch are connected in parallel and then supply power to the BMS. According to the utility model, the battery pack power supply branch and the external low-voltage power supply branch are arranged in parallel, so that the problem that the BMS cannot be normally started due to the fact that the power supply breaks down or is insufficient in voltage when low-voltage power supply is carried out on the BMS only through one power supply can be solved.

Description

Technical Field

[0001] The utility model relates to a BMS low-voltage power supply circuit and a vehicle, belonging to the technical field of BMS power supply. Background Technique

[0002] With the development of technology, the power supply technology has developed rapidly, and the power supply system has emerged as the times require. In vehicles, in order to improve the space utilization rate and provide good protection for equipment, a box-type vehicle-mounted system has been designed. The power supply system is mainly used to meet the needs of the box-type vehicle-mounted system, provide power for various loads on the vehicle, and support specific functions or tasks of the vehicle. The power supply system mainly includes a battery box. The battery management system (BMS) is a system for managing the battery. Therefore, how to ensure that the battery management system obtains long-term stable low-voltage power supply is crucial.

[0003] In the existing technical solutions, usually only the battery pack is used to supply low-voltage power to the BMS, or only the external low-voltage power supply is directly used to supply low-voltage power to the BMS. In the former case, when the voltage of the battery pack is insufficient to start the BMS, only high-voltage power-off can be performed and the work is stopped; in the latter case, when the voltage of the external low-voltage power supply is insufficient, the BMS cannot be started either, or the BMS can be started, but the contactor coil controlled by the BMS (such as at 24V) cannot be normally attracted, and it runs with insufficient power for a long time, which will lead to the contactor adhesion failure, resulting in the abnormal operation of the power supply system and the increase of maintenance costs.

[0004] The Chinese invention patent application publication document with the publication number of CN110450675A discloses a power battery system, a control method and an electric vehicle. The power battery system of this solution includes a power battery pack, a battery management system (BMS) for managing the power battery pack, a switching power supply and a cut-off switch. When the vehicle needs to start running, first close the cut-off switch connected to the switching power supply, the high voltage of the power battery pack is connected to the switching power supply, and a stable low-voltage power supply is output through the switching power supply to activate the BMS and the low-voltage component part of the whole vehicle. After the BMS detects that the low-voltage circuit starts normally, it controls the connection of the high-voltage circuit of the power battery pack and the whole vehicle.

[0005] In summary, the above existing technologies only supply low-voltage power to the BMS through one power supply. When this power supply fails or the voltage is insufficient, the BMS cannot be started normally. Content of the Utility Model

[0006] The purpose of the utility model is to provide a BMS low-voltage power supply circuit and a vehicle, so as to solve the problem that when only one power supply is used to supply low-voltage power to the BMS, the BMS cannot be started normally due to the failure or insufficient voltage of this power supply.

[0007] To achieve the above purpose, the solution of the utility model includes:

[0008] A BMS low-voltage power supply circuit includes a battery pack power supply branch connected in parallel across the two ends of the battery pack and an external low-voltage power supply branch connected in parallel across the two ends of the external low-voltage power supply. A battery pack low-voltage power-on switch is connected in series on the battery pack power supply branch, and an external low-voltage power supply power-on switch is connected in series on the external low-voltage power supply branch; after the battery pack power supply branch and the external low-voltage power supply branch are connected in parallel, they supply power to the BMS.

[0009] Further, after the battery pack power supply branch and the external low-voltage power supply branch are connected in parallel, they are connected to the input side of the DC / DC, and the output side of the DC / DC is connected to the BMS.

[0010] Further, a first diode is connected in series on the battery pack power supply branch, and a second diode is connected in series on the external low-voltage power supply branch. The conduction direction of the first diode is the same as the direction of the battery pack output current, and the conduction direction of the second diode is the same as the direction of the external low-voltage power supply output current.

[0011] Further, the control terminal of the charging contactor is connected to the output port of the BMS, the main contact of the charging contactor is arranged on the loop formed by the charger and the battery pack, and the charging control switch is connected to the input port of the BMS.

[0012] Further, the control terminal of the discharging contactor is connected to the output port of the BMS, the main contact of the discharging contactor is arranged on the loop formed by the battery pack and the load, and the discharging control push-button switch is connected to the input port of the BMS.

[0013] Further, the control terminal of the heating contactor is connected to the output port of the BMS, and the main contact of the heating contactor is arranged on the loop formed by the battery pack and the main contact of the charging contactor.

[0014] Further, the battery pack low-voltage power-on switch and the external low-voltage power supply power-on switch are arranged on the external panel of the battery box.

[0015] Further, between the positive electrode of the battery pack and the positive extreme of the input side of the DC / DC, a battery pack low-voltage power-on switch is connected in series through a matching plug and socket for passing through the battery box to realize the quick disassembly and assembly of the battery pack low-voltage power-on switch.

[0016] Further, in the external low-voltage power supply branch, between the two parallel connection points of the battery pack power supply branch and the external low-voltage power supply branch, an external low-voltage power supply power-on switch and an interface for connecting the external low-voltage power supply are connected in series through a matching plug and socket for passing through the battery box to realize the quick disassembly and assembly of the external low-voltage power supply power-on switch and the external low-voltage power supply.

[0017] A vehicle includes a BMS low-voltage power supply circuit, which includes a battery pack power supply branch connected in parallel across the two ends of the battery pack and an external low-voltage power supply branch connected in parallel across the two ends of an external low-voltage power supply. A battery pack low-voltage power-on switch is serially connected on the battery pack power supply branch, and an external low-voltage power supply power-on switch is serially connected on the external low-voltage power supply branch; after the battery pack power supply branch and the external low-voltage power supply branch are connected in parallel, they supply power to the BMS.

[0018] The beneficial effects of the present utility model are as follows:

[0019] The present utility model is an improved invention. A BMS low-voltage power supply circuit and a vehicle of the present utility model include a battery pack power supply branch connected in parallel across the two ends of the battery pack and an external low-voltage power supply branch connected in parallel across the two ends of an external low-voltage power supply. A battery pack low-voltage power-on switch is serially connected on the battery pack power supply branch, and an external low-voltage power supply power-on switch is serially connected on the external low-voltage power supply branch; after the battery pack power supply branch and the external low-voltage power supply branch are connected in parallel, they supply power to the BMS. When the battery pack low-voltage power-on push-button switch is pressed alone, the battery pack power supply branch provides a low-voltage power supply for the BMS; when the external low-voltage power supply power-on push-button switch is pressed alone, the external low-voltage power supply branch provides a low-voltage power supply for the BMS; when the battery pack low-voltage power-on push-button switch and the external low-voltage power supply power-on push-button switch are pressed simultaneously, after the battery pack and the external low-voltage power supply are connected, they provide a low-voltage power supply for the BMS. By connecting the battery pack power supply branch and the external low-voltage power supply branch in parallel, when the battery pack power supply branch cannot enable the BMS to be powered on normally, the external low-voltage power supply branch can be used to enable the BMS to be powered on normally; when the external low-voltage power supply branch cannot enable the BMS to be powered on normally, the battery pack power supply branch can be used to enable the BMS to be powered on normally. Through the above settings, a stable low-voltage power supply can be provided for the BMS, enabling the BMS to be powered on and work normally, and greatly reducing the maintenance cost. Description of the Drawings

[0020] Figure 1 It is the schematic diagram of the BMS low-voltage power supply circuit system of the present utility model. Detailed Embodiments

[0021] To make the purpose, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and embodiments.

[0022] The concept of the present utility model is to provide a BMS low-voltage power supply circuit for ensuring that the BMS obtains long-term stable low-voltage power supply. It includes a battery pack power supply branch connected in parallel across the two ends of the battery pack and an external low-voltage power supply branch connected in parallel across the two ends of the external low-voltage power supply. A battery pack low-voltage power-on switch is connected in series on the battery pack power supply branch, and an external low-voltage power supply power-on switch is connected in series on the external low-voltage power supply branch; the battery pack power supply branch and the external low-voltage power supply branch are connected in parallel to supply power to the BMS. When the battery pack low-voltage power-on push-button switch is pressed alone, the DC / DC converter can convert the voltage provided by the battery pack that is higher than, lower than, or equal to the voltage required by the BMS into the stable voltage required by the BMS, so as to provide a stable low-voltage power supply for the BMS; similarly, when the external low-voltage power supply power-on push-button switch is pressed alone, the external low-voltage power supply can provide a stable low-voltage power supply for the BMS through the DC / DC converter for a wide range of input voltages; when the battery pack low-voltage power-on push-button switch and the external low-voltage power supply power-on push-button switch are pressed simultaneously, after the battery pack and the external low-voltage power supply are connected, they provide a stable low-voltage power supply for the BMS. Through the above settings, when one power supply branch cannot supply power to the BMS, the other power supply branch can supply power to the BMS, effectively realizing the provision of a stable low-voltage power supply for the BMS.

[0023] Embodiment of the BMS low-voltage power supply circuit:

[0024] As Figure 1 shown in the schematic diagram of a BMS low-voltage power supply circuit system, it includes a battery box, an external low-voltage power supply, a charger, and a load. Among them, the battery box is mainly equipped with a battery pack, a heating sheet, a discharge contactor KM1, a charging contactor KM2, a heating contactor KM3, a battery management system (BMS), a diode D1, and a diode D2. The BMS is a system for managing the battery, with functions such as real-time detection of parameters such as the voltage, current, and temperature of the power battery, fault diagnosis functions such as overcharge, over-discharge, and over-temperature of the battery, SOC / SOH estimation, display and alarm, and information management. The charger can supply power to the battery pack through corresponding interfaces, and the battery pack can supply power to the load through corresponding interfaces.

[0025] The battery pack power supply branch connected in parallel across the battery pack includes a series-connected battery pack low-voltage power-on pushbutton switch S3 and a diode D1. The external low-voltage power supply branch connected in parallel across the external low-voltage power supply includes a series-connected external low-voltage power supply power-on pushbutton switch S4 and a diode D2. The conduction direction of diode D1 is the same as the direction of the output current of the battery pack, and the conduction direction of diode D2 is the same as the direction of the output current of the external low-voltage power supply. The battery pack power supply branch and the external low-voltage power supply branch are arranged in parallel. The parallel-connected battery pack power supply branch and external low-voltage power supply branch provide a stable low-voltage power supply for the BMS through a DC / DC converter. When the battery pack low-voltage power-on pushbutton switch S3 is pressed alone, the DC / DC converter can convert the voltage provided by the battery pack that is higher than, lower than, or equal to the required output voltage of the BMS into the stable voltage required by the BMS, so as to provide a stable low-voltage power supply for the BMS. Similarly, when the external low-voltage power supply power-on pushbutton switch S4 is pressed alone, the external low-voltage power supply can provide a stable low-voltage power supply for the BMS through the DC / DC converter for a wide range of input voltages. At this time, the DC / DC converter plays a voltage stabilizing role. When the battery pack low-voltage power-on pushbutton switch S3 and the external low-voltage power supply power-on pushbutton switch S4 are pressed simultaneously, after the battery pack and the external low-voltage power supply are connected, they provide a low-voltage power supply for the BMS, thus realizing that the battery pack and the external low-voltage power supply simultaneously provide a low-voltage power supply for the BMS, which can avoid the problem that the BMS cannot be powered on and work properly due to a failure or insufficient voltage of either party, and greatly reduces the maintenance cost. Diodes D1 and D2 are respectively arranged on the battery pack power-on branch and the external low-voltage power supply power-on branch. On the one hand, the setting of diode D2 can prevent the current of the battery pack from flowing to the external low-voltage power supply and causing a circuit failure, and the setting of diode D1 can prevent the current of the external low-voltage power supply from flowing to the battery pack and causing a circuit failure. On the other hand, when the battery pack power-on branch and the external low-voltage power supply power-on branch are connected in parallel, the setting of diodes D1 and D2 can effectively prevent overcharging of one party and over-discharging of the other party, resulting in component damage.

[0026] The battery box external panel is equipped with pushbutton switches S1, S2, S3, S4 with lights. Among them, S1 is the discharge control pushbutton switch, S2 is the charge control pushbutton switch, S3 is the battery pack low-voltage power-on pushbutton switch, and S4 is the external low-voltage power supply power-on pushbutton switch. Setting S1, S2, S3, S4 on the battery box external panel can facilitate the user's operation.

[0027] XS03 is a socket set on the outer panel of the battery box, and XP03 is a plug set outside the battery box. A low-voltage power-on switch for the battery pack is connected in series between the positive electrode of the battery pack and the positive terminal of the input side of the DC / DC through a matching plug and socket used to pass through the battery box. When the low-voltage power-on switch of the battery pack cannot be used normally, the low-voltage power-on switch of the battery pack can be replaced by replacing the plug. In the external low-voltage power supply branch, an external low-voltage power supply power-on switch and an external low-voltage power supply are connected in series between the two parallel connection points of the battery pack power supply branch and the external low-voltage power supply branch through a matching plug and socket used to pass through the battery box. When the external low-voltage power supply and the external low-voltage power supply power-on switch cannot be used normally, the external low-voltage power supply and the external low-voltage power supply power-on switch can be replaced by replacing the plug. Through the above settings, faulty equipment can be replaced more conveniently, thus providing a stable low-voltage power supply for the BMS.

[0028] The coils of the control terminals of the discharge contactor KM1, the charge contactor KM2, and the heating contactor KM3 are respectively connected to the output ports of the input / output ports of the BMS. The main contacts of the discharge contactor KM1 are set on the loop formed by the battery pack and the load. The main contacts of the charge contactor KM2 are set on the loop formed by the charger and the battery pack. The main contacts of the heating contactor KM3 are set on the loop formed by the battery pack and the contacts of the charge contactor. The discharge control push-button switch S1 and the charge control push-button switch S2 are respectively connected to the input ports of the input / output ports of the BMS. By controlling the discharge contactor KM1, the charge contactor KM2, and the heating contactor KM3 respectively through the BMS, automatic control of charging, discharging, and heating can be achieved.

[0029] The on - off of the power supply of the battery system can be manually controlled through the discharge control button switch S1 and the charge control button switch S2. When the battery system needs to discharge, manually press the discharge control button switch S1. After the BMS detects the opening and closing state of the switch S1, it outputs a signal to control the coil of the discharge contactor KM1 to be energized, so that the main contact of the discharge contactor KM1 closes, and enters the discharge mode. If there is an abnormal discharge or the discharge needs to be stopped during the discharge process, manually press the discharge control button switch S1 again. After the BMS detects the opening and closing state of the switch S1 again, it outputs a signal to control the coil of KM1 to lose power, so that the main contact of KM1 disconnects, cutting off the discharge circuit; when the battery system needs to charge, manually press the charge control button switch S2. After the BMS detects the opening and closing state of the switch S2, it outputs a signal to control the coil of the charge contactor KM2 to be energized, so that the main contact of the charge contactor KM2 closes. When the BMS monitors the online message of the charger, it enters the charging mode. If there is an abnormal charging or the charging needs to be stopped during the charging process, manually press the charge control button switch S2 again. After the BMS detects the opening and closing state of the switch S2 again, it outputs a signal to control the coil of KM2 to lose power, so that the main contact of KM2 disconnects, cutting off the charging circuit. Controlling the charging and discharging of the circuit through the discharge control button switch S1 and the charge control button switch S2 avoids the singularity that the battery system only accepts the power - on and power - off commands of the whole vehicle, and further increases the safety and reliability of the system.

[0030] When the battery needs to be heated, the BMS determines whether to enter the heating mode according to the current collected cell temperature conditions. The heating mode can be divided into an internal heating mode from the battery pack and an external heating mode from the charger. In the case of the internal heating mode, the BMS sequentially controls the coils of the charge contactor KM2 and the heating contactor KM3 to be energized, and the main contacts of the charge contactor KM2 and the heating contactor KM3 close, entering the internal heating mode; in the case of the external heating mode, the BMS sequentially controls the coils of the charge contactor KM2 and the heating contactor KM3 to be energized, the main contacts of the charge contactor KM2 and the heating contactor KM3 close, and at the same time, when the online message of the charger is detected, it enters the external heating mode.

[0031] As another embodiment, a fuse FU1 is provided between the power supply branch of the parallel - set battery packs and the external low - voltage power supply branch and the positive electrode of the battery, and a fuse FU2 is provided between the charge contactor KM2 and the heating contactor KM3. The setting of the fuses FU1 and FU2 can effectively prevent damage caused by circuit overload and short - circuit, thus ensuring the safety of the system.

[0032] As another embodiment, a shunt RW is provided on the branch connected to the negative electrode of the battery, which can effectively manage the power supply, signals and data streams, and realize the function distribution and coordination of the circuit.

[0033] Vehicle embodiment:

[0034] A vehicle according to this embodiment includes a battery management system for managing the battery, and also includes a BMS low-voltage power supply circuit for providing long-term stable low-voltage power supply to the battery management system. The BMS low-voltage power supply circuit has been introduced clearly enough in the BMS low-voltage power supply circuit embodiment, and will not be elaborated here.

Claims

1. A BMS low voltage power supply circuit, characterized in that: It includes a battery pack power supply branch connected in parallel at both ends of the battery pack and an external low-voltage power supply branch connected in parallel at both ends of the external low-voltage power supply, the battery pack power supply branch is connected in series with a battery pack low-voltage power-on switch, and the external low-voltage power supply branch is connected in series with an external low-voltage power supply power-on switch; the battery pack power supply branch and the external low-voltage power supply branch are connected in parallel to power the BMS.

2. The BMS low voltage power supply circuit according to claim 1, characterized in that: The battery pack power supply branch and the external low-voltage power supply branch are connected in parallel to a DC / DC input side, and a DC / DC output side is connected to the BMS.

3. The BMS low voltage power supply circuit according to claim 1, characterized in that: A first diode is connected in series on the battery pack power supply branch, and a second diode is connected in series on the external low-voltage power supply branch. The conduction direction of the first diode is the same as the output current direction of the battery pack, and the conduction direction of the second diode is the same as the output current direction of the external low-voltage power supply.

4. The BMS low voltage power supply circuit according to claim 1, characterized in that: The control end of the charging contactor is connected to the output port of the BMS, the main contact of the charging contactor is arranged on the loop formed by the charger and the battery pack, and the charging control switch is connected to the input port of the BMS.

5. The BMS low voltage power supply circuit according to claim 1, characterized in that: The discharge contactor control terminal is connected to the output port of the BMS, the discharge contactor main contact is arranged on the loop formed by the battery pack and the load, and the discharge control button switch is connected to the input port of the BMS.

6. The BMS low voltage power supply circuit according to claim 1, characterized in that: The control end of the heating contactor is connected to the output port of the BMS, and the main contact of the heating contactor is arranged on the loop formed by the battery pack and the main contact of the charging contactor.

7. The BMS low voltage power supply circuit according to claim 1, characterized in that: The battery pack low voltage power-on switch and the external low voltage power supply power-on switch are arranged on an external panel of the battery box.

8. The BMS low voltage power supply circuit according to claim 1, characterized in that: The battery pack low-voltage power-on switch is connected in series between the positive electrode of the battery pack and the positive terminal of the DC / DC input side through a matching plug and socket for passing through the battery box, so as to realize rapid disassembly and assembly of the battery pack low-voltage power-on switch.

9. The BMS low voltage power supply circuit according to claim 1, characterized in that: In the external low-voltage power supply branch, the external low-voltage power supply power-on switch and the interface for connecting the external low-voltage power supply are connected in series between the two parallel connection points of the battery pack power supply branch and the external low-voltage power supply branch through a matching plug and socket for passing through the battery box, so as to realize rapid disassembly and assembly of the external low-voltage power supply power-on switch and the external low-voltage power supply.

10. A vehicle, comprising a BMS low voltage power supply circuit, characterized in that: It includes a battery pack power supply branch connected in parallel at both ends of the battery pack and an external low-voltage power supply branch connected in parallel at both ends of the external low-voltage power supply, the battery pack power supply branch is connected in series with a battery pack low-voltage power-on switch, and the external low-voltage power supply branch is connected in series with an external low-voltage power supply power-on switch; the battery pack power supply branch and the external low-voltage power supply branch are connected in parallel to power the BMS.

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