BMS low-voltage power supply control circuit

Abstract

The invention discloses a BMS low-voltage power supply control circuit which is provided with a pre-charging switch control unit, a DCDC unit and a BMS main controller. The BMS main controller controls the pre-charging switch control unit to be in the first working state, so that after the pre-charging switch control unit pre-charges the DCDC unit, the BMS main controller controls the pre-charging switch control unit to be in the second working state, and after the pre-charging switch control unit transmits a high-voltage electric signal output by the battery pack to the DCDC unit for voltage reduction, the pre-charging switch control unit controls the pre-charging switch control unit to be in the second working state. And outputting a low-voltage electric signal to provide a working power supply for the BCU and the BMU in the BMS, so as to solve the problems of poor applicability, high cost and low power consumption caused by the fact that a UPS needs to be additionally arranged when low-voltage power supply is carried out on the BMS in the prior art. Or after the battery pack is directly connected to the relay, the high voltage is directly output to the DCDC unit for voltage reduction, and then the low voltage is output for supplying power to the BMS, so that adhesion is generated when the relay is closed, and the safety and the stability are poor.

Description

Technical Field

[0001] The present invention relates to the technical field of BMS power supply, and in particular to a BMS low-voltage power supply control circuit. Background Art

[0002] In the energy storage battery system, BMS plays a key role in the stable and safe operation of battery power management. Therefore, ensuring the safe and stable power supply of BMS is a prerequisite for ensuring the operation of BMS. In the related technology, BMS power supply is mainly supplied by an external UPS, or the battery pack outputs high voltage and then outputs low voltage through DCDC to achieve simple power supply for BMS. However, the above two ways of powering BMS have different problems. Using an external UPS to power BMS requires additional power supply installation space and equipment costs; the battery pack outputs high voltage and then outputs low voltage through DCDC to power BMS, which requires additional relay control. The coil in the relay itself will increase power consumption. At the same time, when the relay is closed, it is easy to produce adhesion, resulting in circuit failure.

[0003] Therefore, how to solve the technical problems existing in the BMS low-voltage power supply in the related technology has become a difficult problem that technical personnel in this field need to solve. Summary of the invention

[0004] The present invention proposes a BMS low-voltage power supply control circuit to solve the technical problems of poor applicability, high cost and poor safety in the BMS low-voltage power supply in the related art.

[0005] A BMS low-voltage power supply control circuit in the present invention includes:

[0006] A pre-charging switch control unit, wherein an input end of the pre-charging switch control unit is connected to the positive electrode of the battery pack;

[0007] A DCDC unit, wherein the output end of the pre-charge switch control unit is connected to the positive input end of the DCDC unit, and the negative input end of the DCDC unit is connected to the negative electrode of the battery pack;

[0008] The BMS main controller is connected to the control end of the pre-charging switch control unit to control the switch state of the pre-charging switch control unit so that the pre-charging switch control unit supplies power to the DCDC unit after pre-charging.

[0009] A BMS low-voltage power supply control circuit according to an embodiment of the present invention has at least the following beneficial effects:

[0010] The embodiment of the present invention provides a BMS low-voltage power supply control circuit, which is provided with a pre-charging switch control unit, a DCDC unit and a BMS main controller; wherein the input end of the pre-charging switch control unit is connected to the positive electrode of a battery pack, the output end of the pre-charging switch control unit is connected to the positive electrode input end of the DCDC unit, and the negative electrode input end of the DCDC unit is connected to the negative electrode of the battery pack. The pre-charging switch control unit is controlled by the BMS main controller to be in a first working state, so that after the pre-charging switch control unit pre-charges the DCDC unit, the BMS main controller controls the pre-charging switch control unit to be in a second working state, so that the pre-charging switch control unit transmits the high-voltage electrical signal output by the battery pack to the DCDC unit for voltage reduction, and then outputs a low-voltage electrical signal to provide a working power supply for a BCU and a BMU in the BMS, thereby solving the technical problems of poor applicability and high cost of additionally setting up UPS power supply when providing low-voltage power supply to the BMS in the related art, or directly outputting high voltage to the DCDC unit after connecting the battery pack to a relay for voltage reduction and then outputting low voltage for powering the BMS, which easily leads to poor safety and stability when the relay is closed, and providing a low-cost, stable, safe and highly applicable BMS low-voltage power supply control circuit.

[0011] According to some other embodiments of the present invention, the BMS low-voltage power supply control circuit further includes a first anti-reverse unit, which is arranged on a connection line between the pre-charge switch control unit and the positive electrode of the battery pack.

[0012] According to some other embodiments of the BMS low-voltage power supply control circuit of the present invention, the second anti-reverse unit is arranged on the connection line between the output end of the pre-charge switch control unit and the positive input end of the DCDC unit.

[0013] According to some other embodiments of the present invention, the BMS low-voltage power supply control circuit further includes a third anti-reverse unit, which is arranged on a connection line between the DCDC negative input terminal and the negative electrode of the battery pack.

[0014] According to some other embodiments of the BMS low-voltage power supply control circuit of the present invention, the pre-charge switch control unit includes a pre-charge control unit and a power supply control unit;

[0015] The input end of the pre-charging control unit and the input end of the power supply control unit are both connected to the positive electrode of the battery pack, the output end of the pre-charging control unit and the output end of the power supply control unit are both connected to the positive input end of the DCDC unit, the control end of the pre-charging control unit is connected to the pre-charging control end of the BMS main controller, and the control end of the power supply control unit is connected to the power supply control end of the BMS main controller.

[0016] According to some other embodiments of the BMS low-voltage power supply control circuit of the present invention, the pre-charge control unit includes a first resistor and a first switch tube;

[0017] One end of the first resistor is connected to the positive electrode of the battery pack, the other end of the first resistor is connected to the input end of the first switch tube, the output end of the first switch tube is connected to the positive input end of the DCDC unit, and the control end of the first switch tube is connected to the pre-charge control end of the BMS main controller.

[0018] According to some other embodiments of the BMS low-voltage power supply control circuit of the present invention, the power supply control unit includes a second switch tube;

[0019] The input end of the second switch tube is connected to the positive electrode of the battery pack, the output end of the second switch tube is connected to the positive input end of the DCDC unit, and the control end of the second switch tube is connected to the control end of the BMS main controller.

[0020] According to some other embodiments of the BMS low-voltage power supply control circuit of the present invention, it also includes a fourth anti-reverse unit, one end of the fourth anti-reverse unit is connected to the positive electrode of the external power supply device, and the other end of the fourth anti-reverse unit is connected to the positive input terminal of the DCDC.

[0021] According to some other embodiments of the BMS low-voltage power supply control circuit of the present invention, it also includes a fifth anti-reverse unit, one end of the fifth anti-reverse unit is connected to the negative electrode of the external power supply device, and the other end of the fifth anti-reverse unit is connected to the negative electrode input terminal of the DCDC unit.

[0022] According to some other embodiments of the present invention, the BMS low voltage power supply control circuit further includes a first relay switch and a second relay switch;

[0023] One end of the first relay switch is connected to the positive electrode of the battery pack, and a second end of the first relay switch is connected to the positive electrode of an external power supply device;

[0024] One end of the second relay switch is connected to the negative electrode of the battery pack, and the other end of the second relay switch is connected to the negative electrode of the external power supply device;

[0025] The control end of the first relay switch and the control end of the second relay switch are respectively connected to the control end of the BMS main controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the module composition of a first embodiment of a BMS low-voltage power supply control circuit of the present invention;

[0027] Figure 2This is a schematic diagram of the module composition of a second embodiment of a BMS low-voltage power supply control circuit of the present invention;

[0028] Figure 3 It is a schematic diagram of the module composition of the third embodiment of a BMS low-voltage power supply control circuit of the present invention;

[0029] Figure 4 It is a schematic diagram of the module composition of the fourth embodiment of a BMS low-voltage power supply control circuit of the present invention;

[0030] Figure 5 It is a schematic diagram of the module composition of the fifth embodiment of a BMS low-voltage power supply control circuit of the present invention;

[0031] Figure 6 It is a schematic diagram of the module composition of the sixth embodiment of a BMS low-voltage power supply control circuit of the present invention;

[0032] Figure 7 The present invention is a schematic diagram of a BMS low-voltage power supply control circuit according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the concept of the invention and the technical effects produced in combination with the embodiments, so as to fully understand the purpose, characteristics and effects of the invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of them. Based on the embodiments of the invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the invention.

[0034] In the description of the embodiments of the present invention, if "several" is involved, it means more than one, if "multiple" is involved, it means more than two, if "greater than", "less than" or "exceed" is involved, it should be understood as not including the number itself, if "above", "below" or "within" is involved, it should be understood as including the number itself. If "first" or "second" is involved, it should be understood as being used to distinguish technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] Reference Figure 1An embodiment of the present invention provides a BMS low-voltage power supply control circuit, which includes a pre-charge switch control unit, a DCDC unit, and a BMS main controller; wherein the input end of the pre-charge switch control unit is connected to the positive electrode of the battery pack, the output end of the pre-charge switch control unit is connected to the positive electrode input end of the DCDC unit, the negative electrode input end of the DCDC unit is connected to the negative electrode of the battery pack, and the BMS main controller is connected to the control end of the pre-charge switch control circuit to control the working state of the pre-charge switch control unit. In this embodiment, when it is necessary to supply low voltage power to the BMS, the BMS main board is first put into working state by controlling the external electronic switch to close, and then the BMS main controller on the BMS main board controls the pre-charging switch control unit to work, so that the pre-charging switch control unit pre-charges the DCDC unit, and then the BMS main controller controls the pre-charging switch control unit to close and input the high-voltage DC signal output by the battery pack into the DCDC unit for voltage reduction, and the DCDC unit outputs a low-voltage 24V signal to provide working power for the BCU and BMU in the BMS, which solves the poor applicability and high cost of additional UPS power supply required for low-voltage power supply to the BMS in the related art, or the technical problems of poor safety and stability caused by directly outputting high voltage to the DCDC unit after the battery pack is connected to the relay and then outputting low voltage to power the BMS, which easily leads to adhesion when the relay is closed; at the same time, by setting the pre-charging switch control unit to pre-charge the DCDC unit and then supply power when power is turned on, it can avoid the problem of directly charging the capacitor in the DCDC unit to cause high voltage and then causing overcurrent to damage the switch device in the pre-charging switch control unit.

[0036] Reference Figure 2 In some implementations, in order to realize the pre-charging of the DCDC unit and the normal power supply after pre-charging, the pre-charging switch control unit in this embodiment includes a pre-charging control unit and a power supply control unit. Among them, the input end of the pre-charging control unit and the input end of the power supply control unit are both connected to the positive electrode of the battery pack, the output end of the pre-charging control unit and the output end of the power supply control unit are both connected to the positive input end of the DCDC unit, the pre-charging control end of the BMS main controller is connected to the control end of the pre-charging control unit, and the power supply control end of the BMS main controller is connected to the control end of the power supply control unit. In this embodiment, when low-voltage power-on is performed, the BMS main controller controls the pre-charging control unit to be in a closed conduction state, and the power supply control unit is in a disconnected cut-off state. Then, after the pre-charging control unit pre-charges the DCDC unit for a preset time, the BMS main controller controls the power supply control unit to be in a closed conduction state, avoiding the direct power supply to the DCDC unit to generate a large current that is easy to damage the components in the power supply control unit. After the power supply control unit is closed and the DCDC unit outputs a low-voltage power supply signal to the BCU and BMU, the BMS main controller controls the pre-charging control unit to disconnect and complete the low-voltage power supply process.

[0037] Reference Figure 3 In some embodiments, in order to prevent the reverse voltage generated when the pre-charge switch control unit is working and affect the normal operation or service life of the battery pack, a first anti-reverse unit is also provided in this embodiment. Among them, the first end of the first anti-reverse unit is connected to the positive electrode of the battery pack, and the second end of the first anti-reverse unit is connected to the input end of the pre-charge switch control unit. In some specific embodiments, the first anti-reverse unit includes a first diode, the anode of the first diode is connected to the positive electrode of the battery pack, and the cathode of the first diode is connected to the input end of the pre-charge switch control unit. Furthermore, by providing the first diode on the connection line between the positive electrode of the battery pack and the pre-charge switch control unit, the current signal output from the battery pack flows unidirectionally to the pre-charge switch control unit, thereby protecting the battery pack during circuit operation.

[0038] Reference Figure 4 In some embodiments, in order to prevent the reverse voltage generated by the DCDC unit from affecting the normal operation of the pre-filling switch control unit or the service life of the components therein when the DCDC unit is working, a second anti-reverse unit is further provided in this embodiment. Among them, one end of the second anti-reverse unit is connected to the output end of the pre-filling switch control unit, and the other end of the second anti-reverse unit is connected to the positive input end of the DCDC unit. In some specific embodiments, the second anti-reverse unit includes a second diode, the anode of the second diode is connected to the output end of the pre-filling switch control unit, and the cathode of the second diode is connected to the positive input end of the DCDC unit. Then, by providing a second diode on the connection line between the output end of the pre-filling switch control unit and the positive input end of the DCDC unit, the current signal output from the pre-filling switch control unit flows unidirectionally to the DCDC unit, which protects the components in the pre-filling switch control unit during circuit operation.

[0039] Reference Figure 5 In some embodiments, in order to prevent the reverse voltage generated when the battery pack is working from affecting the normal operation of the DCDC unit or the service life of the devices therein, the present embodiment also includes a third anti-reverse unit. Among them, one end of the third anti-reverse unit is connected to the negative input end of the DCDC unit, and the other end of the third anti-reverse unit is connected to the negative electrode of the battery pack. In some specific embodiments, the third anti-reverse unit includes a third diode, the anode of the third diode is connected to the negative input end of the DCDC unit, and the cathode of the third diode is connected to the negative electrode of the battery pack. Then, by providing a third diode on the connection line between the negative input end of the DCDC unit and the negative electrode of the battery pack, the current signal output from the DCDC unit flows unidirectionally to the negative electrode of the battery pack, which protects the devices in the DCDC unit during the operation of the circuit.

[0040] Reference Figure 6In some embodiments, in order to still be able to control the pre-charge switch control circuit described in the above embodiment when the battery pack is over-discharged and lacks power to prevent the battery pack from being seriously over-discharged and causing the battery pack life to be affected, a fourth anti-reverse unit and a fifth anti-reverse unit are also provided in this embodiment, one end of the fourth anti-reverse unit is connected to the positive electrode P+ of the external power supply device, and the other end of the fourth anti-reverse unit is connected to the positive input end of the DCDC unit; one end of the fifth anti-reverse unit is connected to the negative electrode P- of the external power supply device, and the other end of the fifth anti-reverse unit is connected to the negative input end of the DCDC unit. In some specific embodiments, the fourth anti-reverse unit includes a fourth diode and a fifth diode connected in series, and the fifth anti-reverse unit includes a sixth diode, the anode of the fourth diode is connected to the positive electrode P+ of the external power supply device, and the cathode of the fifth diode is connected to the positive input end of the DCDC unit; the anode of the sixth diode is connected to the negative input end of the DCDC unit, and the cathode of the sixth diode is connected to the negative electrode P- of the external power supply device. In this embodiment, a fourth diode and a fifth diode connected in series are provided on the connection line between the DCDC unit and the positive electrode P+ of the external power supply device, so that the current signal output from the positive electrode P+ of the external power supply device flows unidirectionally to the DCDC unit, which protects the external power supply device during circuit operation. At the same time, a sixth diode is provided on the connection line between the negative input terminal of the DCDC unit and the negative electrode P- of the external power supply device, so that the current output by the DCDC unit flows unidirectionally to the negative electrode P- of the external power supply device, which protects the device in the DCDC unit during circuit operation. In other embodiments, the external power supply device includes an energy storage converter, which is used to charge the battery pack after connecting to the AC power of the power grid.

[0041] Reference Figure 7 The following is a specific implementation method of the BMS low-voltage power supply control circuit provided by the embodiment of the present invention. It should be noted that this embodiment is only used as a specific embodiment. No creative improvement is made on this embodiment. Only various simple changes are made and still fall within the protection scope of the BMS low-voltage power supply control circuit proposed in the embodiment of the present invention.

[0042] In this embodiment, the pre-charge control unit includes a first resistor R1 and a first switch tube Q1, and the power supply control unit includes a second switch tube Q2; wherein, the first switch tube Q1 and the second switch tube Q2 are exemplified by MOS tubes, and other types of switch tubes such as IGBT, GaN, etc. can also replace MOS tubes to realize the functions of the first switch tube Q1 and the second switch tube Q2. The first anti-reverse unit includes a first diode D1, the second anti-reverse unit includes a second diode D2, the third anti-reverse unit includes a third triode D3, the fourth anti-reverse unit includes a fourth diode D4 and a fifth diode D5 connected in series, and the fifth anti-reverse unit includes a sixth diode D6. In this embodiment, a first relay Pos_Relay and a second relay Neg_Relay are also provided, and the two ends of the first relay Pos_Relay are respectively connected to the positive electrode B+ of the battery pack and the positive electrode P+ of the energy storage converter, and the two ends of the second relay Neg_Relay are respectively connected to the negative electrode B- of the battery pack and the negative electrode P- of the energy storage converter, and then after the BMS low voltage power-on is completed, the first relay Pos_Relay and the second relay Neg_Relay are controlled to realize the charging of the battery pack.In this embodiment, one end of the first resistor R1 is connected to the drain (input end) of the first MOS tube Q1, the positive electrode B+ of the battery pack is connected to the other end of the first resistor R1 after being connected in series with the first diode D1, the source (output end) of the first MOS tube Q1 is connected to the positive input end of the DCDC unit after being connected in series with the second diode D2, the control end of the first MOS tube Q1 is connected to the pre-charge control end Pow_pre_ctrl of the BMS main controller, the drain (input end) of the second MOS tube Q2 is connected to the connection point of the first resistor R1 and the first diode D1, the source (output end) of the second MOS tube Q2 is connected to the connection point of the source of the first MOS tube Q1 and the second diode D2, the control end of the second MOS tube Q2 is connected to the power supply control end Pow_on_ctrl of the BMS main controller, the anode of the third transistor D3 is connected to the negative input end of the DCDC unit, the cathode of the third transistor D3 is connected to the negative electrode B- of the battery pack, and the fourth diode D 4 and the fifth diode D5 are connected in series, the anode of the fourth diode D4 is connected to the positive electrode P+ of the energy storage converter, the cathode of the fifth diode D5 is connected to the positive input terminal of the DCDC unit, the anode of the sixth diode is connected to the negative input terminal of the DCDC unit, the cathode of the sixth diode is connected to the negative electrode P- of the energy storage converter, the positive output terminal 24V+ of the DCDC outputs a low voltage signal to power the BCU and BMU, and the negative output terminal of the DCDC unit is connected to the power ground. At the same time, an electromagnetic switch P1 is also provided in this example, one end of the electromagnetic switch P1 is connected to the positive output terminal 24V+ of the DCDC, the other end of the electromagnetic switch P1 is connected to the power supply interface BMU_POW+ of the BMU, the control end of the electromagnetic switch P1 is connected to the BMU power supply control end Bmu_Pow_ctrl of the BCU controller, and the ground end of the electromagnetic switch P1 is connected to the power ground, and then the BCU controller controls the closed state of the electromagnetic switch P1 to realize the control of the low-voltage power supply of the BMU. In this embodiment, by connecting the first resistor R1 in series, when the BMS main controller controls the first MOS tube Q1 to be turned on, the capacitor in the DCDC unit is pre-charged by a small current, and then after a set time, the BMS main controller controls the second MOS tube Q2 to be turned on to prevent the capacitor in the DCDC unit from charging and generating a large current to break down the second MOS tube Q2 when no pre-charging is performed. After the second MOS tube Q2 is closed, the DCDC unit starts to work and outputs a 24V low voltage to provide a low-voltage working power supply for the BCU and BMU. At this time, the BMS main controller controls the first MOS tube Q1 to be turned off, and controls the first relay Pos_Relay and the second relay Neg_Relay to be closed, so that the energy storage converter converts the AC power of the power grid into DC power to charge the battery pack.When the battery pack is not charged and is depleted, the energy storage converter converts the AC power of the grid into DC power for the DCDC unit to step down and then supply power to the BCU and BMU. At this time, the BMS main controller cuts off the power supply to the BCU and BMU, controls the second MOS tube Q2 to be cut off, stops the battery pack from continuing to output power to supply the DCDC unit, and prevents the battery pack from being seriously depleted, which affects the service life of the battery pack.

[0043] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A BMS low voltage power supply control circuit, characterized in that: include: A pre-charging switch control unit, wherein an input end of the pre-charging switch control unit is connected to the positive electrode of the battery pack; A DCDC unit, wherein the output end of the pre-charge switch control unit is connected to the positive input end of the DCDC unit, and the negative input end of the DCDC unit is connected to the negative electrode of the battery pack; The BMS main controller is connected to the control end of the pre-charging switch control unit to control the switch state of the pre-charging switch control unit so that the pre-charging switch control unit supplies power to the DCDC unit after pre-charging.

2. The BMS low voltage power supply control circuit according to claim 1, characterized in that: It also includes a first anti-reverse unit, which is arranged on the connection line between the pre-charge switch control unit and the positive electrode of the battery pack.

3. The BMS low voltage power supply control circuit according to claim 2, characterized in that: It also includes a second anti-reverse unit, which is arranged on a connection line between the output end of the pre-charge switch control unit and the positive input end of the DCDC unit.

4. The BMS low voltage power supply control circuit according to claim 3, characterized in that: It also includes a third anti-reverse unit, which is arranged on the connection line between the negative electrode input terminal of the DCDC and the negative electrode of the battery pack.

5. The BMS low voltage power supply control circuit according to any one of claims 1 to 4, characterized in that: The pre-charging switch control unit includes a pre-charging control unit and a power supply control unit; The input end of the pre-charging control unit and the input end of the power supply control unit are both connected to the positive electrode of the battery pack, the output end of the pre-charging control unit and the output end of the power supply control unit are both connected to the positive input end of the DCDC unit, the control end of the pre-charging control unit is connected to the pre-charging control end of the BMS main controller, and the control end of the power supply control unit is connected to the power supply control end of the BMS main controller.

6. The BMS low voltage power supply control circuit according to claim 5, characterized in that: The pre-charging control unit includes a first resistor and a first switch tube; One end of the first resistor is connected to the positive electrode of the battery pack, the other end of the first resistor is connected to the input end of the first switch tube, the output end of the first switch tube is connected to the positive input end of the DCDC unit, and the control end of the first switch tube is connected to the pre-charge control end of the BMS main controller.

7. The BMS low voltage power supply control circuit according to claim 5, characterized in that: The power supply control unit includes a second switch tube; The input end of the second switch tube is connected to the positive electrode of the battery pack, the output end of the second switch tube is connected to the positive input end of the DCDC unit, and the control end of the second switch tube is connected to the control end of the BMS main controller.

8. The BMS low voltage power supply control circuit according to claim 6 or 7, characterized in that: It also includes a fourth anti-reverse unit, one end of which is connected to the positive electrode of the external power supply device, and the other end of which is connected to the positive input end of the DCDC.

9. The BMS low voltage power supply control circuit according to claim 8, characterized in that: It also includes a fifth anti-reverse unit, one end of which is connected to the negative electrode of the external power supply device, and the other end of which is connected to the negative electrode input terminal of the DCDC unit.

10. The BMS low voltage power supply control circuit according to claim 9, characterized in that: Also includes a first relay switch and a second relay switch; One end of the first relay switch is connected to the positive electrode of the battery pack, and a second end of the first relay switch is connected to the positive electrode of an external power supply device; One end of the second relay switch is connected to the negative electrode of the battery pack, and the other end of the second relay switch is connected to the negative electrode of the external power supply device; The control end of the first relay switch and the control end of the second relay switch are respectively connected to the control end of the BMS main controller.

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