BMS low-voltage power supply control circuit

Abstract

The utility model 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] This utility model relates to the field of BMS power supply technology, and in particular to a low-voltage power supply control circuit for BMS. Background Technology

[0002] In energy storage battery systems, the Battery Management System (BMS) plays a crucial role in ensuring the stable and safe operation of battery power management. Therefore, guaranteeing a safe and stable power supply to the BMS is a prerequisite for its operation. In related technologies, BMS power supply is mainly achieved through an external UPS, or by using the high-voltage output from the battery pack via a DC-DC converter to provide a lower voltage for the BMS. However, these two methods of powering the BMS each have their own problems. Using an external UPS requires additional power supply installation space and equipment costs; using the low-voltage output from the battery pack via a DC-DC converter requires additional relay control, but the coils within the relays themselves increase power consumption, and the relays are prone to sticking when closed, leading to circuit failures.

[0003] Therefore, how to solve the technical problems existing in the low-voltage power supply of BMS in related technologies has become a difficult problem that needs to be solved by those skilled in the art. Utility Model Content

[0004] This utility model proposes a low-voltage power supply control circuit for BMS to solve the technical problems of poor applicability, high cost and poor safety in BMS low-voltage power supply in related technologies.

[0005] This utility model discloses a BMS low-voltage power supply control circuit, which includes:

[0006] A precharge switch control unit, the input terminal of which is connected to the positive terminal of the battery pack;

[0007] The output terminal of the precharge switch control unit is connected to the positive input terminal of the DCDC unit, and the negative input terminal of the DCDC unit is connected to the negative terminal of the battery pack.

[0008] The BMS main controller is connected to the control terminal of the precharge switch control unit to control the switching state of the precharge switch control unit, so that the precharge switch control unit precharges the DC-DC unit and then supplies power.

[0009] The BMS low-voltage power supply control circuit of this utility model embodiment has at least the following beneficial effects:

[0010] This utility model discloses a low-voltage power supply control circuit for a battery management system (BMS), comprising a pre-charge switch control unit, a DC-DC converter unit, and a BMS main controller. The input terminal of the pre-charge switch control unit is connected to the positive terminal of the battery pack, and its output terminal is connected to the positive input terminal of the DC-DC converter unit. The negative input terminal of the DC-DC converter unit is connected to the negative terminal of the battery pack. The BMS main controller controls the pre-charge switch control unit to a first operating state, pre-charging the DC-DC converter unit. Then, the BMS main controller controls the pre-charge switch control unit to a second operating state. The precharge switch control unit transmits the high-voltage electrical signal output from the battery pack to the DC-DC unit for step-down, and then outputs a low-voltage electrical signal to provide operating power to the BCU and BMU in the BMS. This solves the technical problems of poor applicability and high cost in related technologies when providing low-voltage power supply to the BMS, which require additional UPS power supply, or poor safety and stability due to the risk of the relay sticking when closing when directly connected to the relay after the battery pack outputs high voltage to the DC-DC unit for step-down and outputting low voltage to power the BMS. It provides a low-cost, stable, safe and highly applicable low-voltage power supply control circuit for BMS.

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

[0012] According to other embodiments of the present invention, the BMS low-voltage power supply control circuit further includes a second anti-reverse unit, which is disposed on the connection line between the output terminal of the precharge switch control unit and the positive input terminal of the DC-DC unit.

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

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

[0015] The input terminals of the precharge control unit and the power supply control unit are both connected to the positive terminal of the battery pack. The output terminals of the precharge control unit and the power supply control unit are both connected to the positive input terminal of the DC-DC unit. The control terminal of the precharge control unit is connected to the precharge control terminal of the BMS main controller, and the control terminal of the power supply control unit is connected to the power supply control terminal of the BMS main controller.

[0016] According to other embodiments of the present invention, the BMS low-voltage power supply control circuit includes a first resistor and a first switching transistor;

[0017] One end of the first resistor is connected to the positive terminal of the battery pack, the other end of the first resistor is connected to the input terminal of the first switching transistor, the output terminal of the first switching transistor is connected to the positive input terminal of the DC-DC unit, and the control terminal of the first switching transistor is connected to the pre-charge control terminal of the BMS main controller.

[0018] According to other embodiments of the present invention, the BMS low-voltage power supply control circuit includes a second switching transistor.

[0019] The input terminal of the second switching transistor is connected to the positive terminal of the battery pack, the output terminal of the second switching transistor is connected to the positive input terminal of the DC-DC unit, and the control terminal of the second switching transistor is connected to the control terminal of the BMS main controller.

[0020] According to other embodiments of the present invention, the BMS low-voltage power supply control circuit further includes a fourth anti-reverse unit, one end of which is connected to the positive terminal of an external power supply device, and the other end of which is connected to the positive input terminal of the DC-DC converter.

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

[0022] The BMS low-voltage power supply control circuit according to some other embodiments of the present invention further includes a first relay switch and a second relay switch.

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

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

[0025] The control terminals of the first relay switch and the second relay switch are respectively connected to the control terminal of the BMS main controller. Attached Figure Description

[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 according to this utility model;

[0027] Figure 2 This is a schematic diagram of the module composition of a second embodiment of a BMS low-voltage power supply control circuit according to this utility model;

[0028] Figure 3 This is a schematic diagram of the module composition of a third embodiment of a BMS low-voltage power supply control circuit of this utility model;

[0029] Figure 4 This is a schematic diagram of the module composition of the fourth embodiment of the BMS low-voltage power supply control circuit of this utility model;

[0030] Figure 5 This is a schematic diagram of the module composition of the fifth embodiment of the BMS low-voltage power supply control circuit of this utility model;

[0031] Figure 6 This is a schematic diagram of the module composition of the sixth embodiment of the BMS low-voltage power supply control circuit of this utility model;

[0032] Figure 7 This is a schematic diagram of the application circuit connection structure of a specific embodiment of the BMS low-voltage power supply control circuit of this utility model. Detailed Implementation

[0033] The following will describe the concept and technical effects of the utility model clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of the utility model. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the utility model without creative effort are all within the protection scope of the utility model.

[0034] In the description of the embodiments of this utility model, the term "several" means one or more, and the term "multiple" means two or more. The terms "greater than," "less than," and "exceeding" should be understood as excluding the stated number, while the terms "above," "below," and "within" should be understood as including the stated number. The terms "first" and "second" should be understood as distinguishing technical features and not as indicating or implying relative importance, the number of indicated technical features, or the order of the indicated technical features.

[0035] Reference Figure 1This utility model provides a BMS low-voltage power supply control circuit, which includes a precharge switch control unit, a DC-DC converter, and a BMS main controller. The input terminal of the precharge switch control unit is connected to the positive terminal of the battery pack, the output terminal of the precharge switch control unit is connected to the positive input terminal of the DC-DC converter, the negative input terminal of the DC-DC converter is connected to the negative terminal of the battery pack, and the BMS main controller is connected to the control terminal of the precharge switch control circuit to control the working state of the precharge switch control unit. In this embodiment, when low-voltage power supply is required to the BMS, the BMS mainboard is first activated by closing an external electronic switch. Then, the BMS main controller on the mainboard controls the pre-charge switch control unit to pre-charge the DC-DC converter. After the pre-charge switch control unit pre-charges the DC-DC converter, the BMS main controller closes the pre-charge switch control unit, inputting the high-voltage DC signal from the battery pack to the DC-DC converter for voltage reduction. The DC-DC converter then outputs a low-voltage 24V signal to provide power to the BCU and BMU in the BMS. This solves the problems of poor applicability and high cost associated with additional UPS power supply for low-voltage power supply to the BMS in related technologies, or the safety and stability issues caused by the relay sticking when closing when directly connected to a relay after high-voltage output to the DC-DC converter for voltage reduction. Furthermore, by pre-charging the DC-DC converter before powering on, the problem of high voltage caused by directly charging the capacitors in the DC-DC converter, leading to overcurrent damage to the switching devices in the pre-charge switch control unit, can be avoided.

[0036] Reference Figure 2 In some implementations, to achieve pre-charging of the DC-DC converter and normal power supply after pre-charging, the pre-charge switch control unit in this embodiment includes a pre-charge control unit and a power supply control unit. The input terminals of both the pre-charge control unit and the power supply control unit are connected to the positive terminal of the battery pack, and the output terminals of both are connected to the positive input terminal of the DC-DC converter. The pre-charge control terminal of the BMS main controller is connected to the control terminal of the pre-charge control unit, and the power supply control terminal of the BMS main controller is connected to the control terminal of the power supply control unit. In this embodiment, during low-voltage power-on, the BMS main controller controls the pre-charge control unit to be in a closed conducting state, and the power supply control unit to be in an open cutoff state. After the pre-charge control unit pre-charges the DC-DC converter for a preset time, the BMS main controller controls the power supply control unit to be in a closed conducting state, avoiding direct power supply to the DC-DC converter which could generate a large current that could easily damage the components in the power supply control unit. After the power supply control unit is closed conducting and the DC-DC converter outputs a low-voltage power supply signal to the BCU and BMU, the BMS main controller controls the pre-charge control unit to be disconnected to complete the low-voltage power supply process.

[0037] Reference Figure 3 In some embodiments, to prevent reverse voltage generated during the operation of the precharge switch control unit from affecting the normal operation or lifespan of the battery pack, a first reverse protection unit is also provided. The first terminal of the first reverse protection unit is connected to the positive terminal of the battery pack, and the second terminal is connected to the input terminal of the precharge switch control unit. In some specific embodiments, the first reverse protection unit includes a first diode, with its anode connected to the positive terminal of the battery pack and its cathode connected to the input terminal of the precharge switch control unit. Therefore, by providing the first diode on the connection line between the positive terminal of the battery pack and the precharge switch control unit, the current signal output from the battery pack flows unidirectionally to the precharge switch control unit, thus protecting the battery pack during circuit operation.

[0038] Reference Figure 4 In some embodiments, to prevent reverse voltage generated by the DC-DC converter during operation from affecting the normal operation of the precharge switch control unit or the lifespan of its components, a second reverse protection unit is also provided. One end of the second reverse protection unit is connected to the output terminal of the precharge switch control unit, and the other end is connected to the positive input terminal of the DC-DC converter. In some specific embodiments, the second reverse protection unit includes a second diode. The anode of the second diode is connected to the output terminal of the precharge switch control unit, and the cathode of the second diode is connected to the positive input terminal of the DC-DC converter. By providing the second diode on the connection line between the output terminal of the precharge switch control unit and the positive input terminal of the DC-DC converter, the current signal output from the precharge switch control unit flows unidirectionally to the DC-DC converter, protecting the components in the precharge switch control unit during circuit operation.

[0039] Reference Figure 5 In some embodiments, to prevent reverse voltage generated during battery pack operation from affecting the normal operation of the DC-DC unit or the lifespan of its components, a third reverse protection unit is also included. One end of the third reverse protection unit is connected to the negative input terminal of the DC-DC unit, and the other end is connected to the negative terminal of the battery pack. In some specific embodiments, the third reverse protection unit includes a third diode. The anode of the third diode is connected to the negative input terminal of the DC-DC unit, and the cathode of the third diode is connected to the negative terminal of the battery pack. By providing the third diode in the connection line between the negative input terminal of the DC-DC unit and the negative terminal of the battery pack, the current signal output from the DC-DC unit flows unidirectionally to the negative terminal of the battery pack, thus protecting the components in the DC-DC unit during circuit operation.

[0040] Reference Figure 6In some embodiments, to ensure that the pre-charge switch control circuit described in the above embodiments can still control the battery pack even when it is over-discharged and depleted, preventing severe over-discharge from affecting the battery pack's lifespan, this embodiment also includes a fourth anti-reverse unit and a fifth anti-reverse unit. One end of the fourth anti-reverse unit is connected to the positive terminal P+ of the external power supply device, and the other end is connected to the positive input terminal of the DC-DC unit. One end of the fifth anti-reverse unit is connected to the negative terminal P- of the external power supply device, and the other end is connected to the negative input terminal of the DC-DC 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 terminal P+ of the external power supply device, and the cathode of the fifth diode is connected to the positive input terminal of the DC-DC unit. The anode of the sixth diode is connected to the negative input terminal of the DC-DC unit, and the cathode of the sixth diode is connected to the negative terminal P- of the external power supply device. In this embodiment, by providing a fourth and fifth diode connected in series on the connection line between the DCDC unit and the positive terminal P+ of the external power supply device, the current signal output from the positive terminal P+ of the external power supply device flows unidirectionally to the DCDC unit, protecting the external power supply device during circuit operation. Simultaneously, a sixth diode is provided on the connection line between the negative input terminal of the DCDC unit and the negative terminal P- of the external power supply device, allowing the current output from the DCDC unit to flow unidirectionally to the negative terminal P- of the external power supply device, protecting the devices 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 being connected to the AC power grid.

[0041] Reference Figure 7 The following specific embodiment illustrates the implementation of the BMS low-voltage power supply control circuit provided by this utility model. It should be noted that this embodiment is merely a specific embodiment, and no creative improvements are made on this embodiment. Various simple changes are still within the protection scope of the BMS low-voltage power supply control circuit proposed by this utility model.

[0042] In this embodiment, the pre-charge control unit includes a first resistor R1 and a first switch Q1, and the power supply control unit includes a second switch Q2. The first switch Q1 and the second switch Q2 are exemplified using MOSFETs, but other types of switches such as IGBTs and GaNs can also replace MOSFETs to achieve the functions of the first switch Q1 and the second switch Q2. The first reverse protection unit includes a first diode D1, the second reverse protection unit includes a second diode D2, the third reverse protection unit includes a third transistor D3, the fourth reverse protection unit includes a fourth diode D4 and a fifth diode D5 connected in series, and the fifth reverse protection unit includes a sixth diode D6. In this embodiment, a first relay Pos_Relay and a second relay Neg_Relay are also provided. The two ends of the first relay Pos_Relay are connected to the positive terminal B+ of the battery pack and the positive terminal P+ of the energy storage converter, respectively. The two ends of the second relay Neg_Relay are connected to the negative terminal B- of the battery pack and the negative terminal P- of the energy storage converter, respectively. After the BMS is powered on at low voltage, the first relay Pos_Relay and the second relay Neg_Relay are controlled to charge the battery pack.In this embodiment, one end of the first resistor R1 is connected to the drain (input terminal) of the first MOSFET Q1. The positive terminal B+ of the battery pack is connected in series with the first diode D1 and then to the other end of the first resistor R1. The source (output terminal) of the first MOSFET Q1 is connected in series with the second diode D2 and then to the positive input terminal of the DC-DC unit. The control terminal of the first MOSFET Q1 is connected to the pre-charge control terminal Pow_pre_ctrl of the BMS main controller. The drain (input terminal) of the second MOSFET Q2 is connected to the connection point of the first resistor R1 and the first diode D1. The source (output terminal) of the second MOSFET Q2 is connected to the connection point of the source of the first MOSFET Q1 and the second diode D2. The control terminal of the second MOSFET Q2 is connected to the power supply control terminal Pow_on_ctrl of the BMS main controller. The anode of the third transistor D3 is connected to the negative input terminal of the DC-DC unit. The cathode of the third transistor D3 is connected to the negative terminal B- of the battery pack. The fourth diode D... After diodes D4 and D5 are connected in series, the anode of the fourth diode D4 is connected to the positive terminal P+ of the energy storage converter, the cathode of the fifth diode D5 is connected to the positive input terminal of the DC-DC unit, the anode of the sixth diode is connected to the negative input terminal of the DC-DC unit, and the cathode of the sixth diode is connected to the negative terminal P- of the energy storage converter. The positive output terminal 24V+ of the DC-DC unit outputs a low-voltage signal to power the BCU and BMU. The negative output terminal of the DC-DC unit is connected to the power supply ground. In this example, an electromagnetic switch P1 is also provided. One end of the electromagnetic switch P1 is connected to the positive output terminal 24V+ of the DC-DC unit, and the other end of the electromagnetic switch P1 is connected to the power supply interface BMU_POW+ of the BMU. The control terminal of the electromagnetic switch P1 is connected to the BMU power supply control terminal Bmu_Pow_ctrl of the BCU controller. The ground terminal of the electromagnetic switch P1 is connected to the power supply ground. Thus, the BCU controller controls the closing state of the electromagnetic switch P1 to control the low-voltage power supply to the BMU. In this embodiment, by connecting a first resistor R1 in series, when the BMS main controller controls the first MOSFET Q1 to turn on, a small current is used to precharge the capacitor in the DC-DC unit. Then, after a set time, the BMS main controller controls the second MOSFET Q2 to turn on, preventing the capacitor in the DC-DC unit from generating a large current that could break down the second MOSFET Q2 if precharging is not performed. After closing the second MOSFET Q2, the DC-DC unit starts working and outputs a 24V low voltage to provide low-voltage operating power to the BCU and BMU. At this time, the BMS main controller controls the first MOSFET Q1 to turn off and controls the first relay Pos_Relay and the second relay Neg_Relay to close, so that the energy storage converter converts the AC power from the grid into DC power to charge the battery pack.When the battery pack is depleted due to lack of charging, the energy storage converter converts the grid AC power into DC power to power the DC-DC unit after stepping down the voltage, which then powers the BCU and BMU. At this time, the BMS main controller cuts off the power supply to the BCU and BMU, controls the second MOSFET Q2 to turn off, and stops the battery pack from continuing to output power to the DC-DC unit, preventing the battery pack from being severely depleted and affecting its service life.

[0043] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A BMS low voltage power supply control circuit, characterized in that, include: A precharge switch control unit, the input terminal of which is connected to the positive terminal of the battery pack; The output terminal of the precharge switch control unit is connected to the positive input terminal of the DCDC unit, and the negative input terminal of the DCDC unit is connected to the negative terminal of the battery pack. The BMS main controller is connected to the control terminal of the precharge switch control unit to control the switching state of the precharge switch control unit, so that the precharge switch control unit precharges the DC-DC unit and then supplies power.

2. The BMS low voltage power supply control circuit of claim 1, wherein, It also includes a first anti-reverse unit, which is disposed on the connection line between the precharge switch control unit and the positive terminal of the battery pack.

3. The BMS low voltage power supply control circuit of claim 2, wherein, It also includes a second anti-reverse unit, which is disposed on the connection line between the output terminal of the precharge switch control unit and the positive input terminal of the DC-DC unit.

4. The BMS low voltage power supply control circuit of claim 3, wherein, It also includes a third anti-reverse unit, which is disposed on the connection line between the negative input terminal of the DC-DC converter and the negative terminal of the battery pack.

5. The BMS low voltage power supply control circuit of any one of claims 1 to 4, wherein, The precharge switch control unit includes a precharge control unit and a power supply control unit; The input terminals of the precharge control unit and the power supply control unit are both connected to the positive terminal of the battery pack. The output terminals of the precharge control unit and the power supply control unit are both connected to the positive input terminal of the DC-DC unit. The control terminal of the precharge control unit is connected to the precharge control terminal of the BMS main controller, and the control terminal of the power supply control unit is connected to the power supply control terminal of the BMS main controller.

6. The BMS low voltage power supply control circuit of claim 5, wherein, The precharge control unit includes a first resistor and a first switching transistor; One end of the first resistor is connected to the positive terminal of the battery pack, the other end of the first resistor is connected to the input terminal of the first switching transistor, the output terminal of the first switching transistor is connected to the positive input terminal of the DC-DC unit, and the control terminal of the first switching transistor is connected to the pre-charge control terminal of the BMS main controller.

7. The BMS low voltage power supply control circuit of claim 5, wherein, The power supply control unit includes a second switching transistor; The input terminal of the second switching transistor is connected to the positive terminal of the battery pack, the output terminal of the second switching transistor is connected to the positive input terminal of the DC-DC unit, and the control terminal of the second switching transistor is connected to the control terminal of the BMS main controller.

8. The BMS low voltage power supply control circuit of claim 6 or 7, wherein, It also includes a fourth anti-reverse unit, one end of which is connected to the positive terminal of an external power supply device, and the other end of which is connected to the positive input terminal of the DC-DC converter.

9. The BMS low voltage power supply control circuit of claim 8, wherein, It also includes a fifth anti-reverse unit, one end of which is connected to the negative terminal of an external power supply device, and the other end of which is connected to the negative input terminal of the DC-DC unit.

10. The BMS low voltage power supply control circuit of claim 9, wherein, It also includes a first relay switch and a second relay switch; One end of the first relay switch is connected to the positive terminal of the battery pack, and the second end of the first relay switch is connected to the positive terminal of an external power supply device. One end of the second relay switch is connected to the negative terminal of the battery pack, and the other end of the second relay switch is connected to the negative terminal 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 with the control end of the BMS main controller.

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