Pre-charge circuit and control method thereof, battery management system, electric vehicle

Abstract

The application discloses a pre-charging circuit and a control method thereof, a battery management system and an electric vehicle. The circuit comprises a capacitor, a power battery, a pre-charging inductor, a pre-charging switch and a switch control module. The positive pole of the power battery is connected with the first end of the capacitor. The first end of the pre-charging inductor is connected with the first end of the capacitor, and the second end of the pre-charging inductor is connected with the second end of the capacitor. The pre-charging switch is connected in series between the negative pole of the power battery and the first end of the pre-charging inductor. The input end of the switch control module is connected with the negative pole of the power battery, and the output end of the switch control module is connected with the pre-charging switch. The switch control module is used for acquiring a circuit signal in the pre-charging circuit, comparing the circuit signal with a reference signal to obtain a voltage value comparison result, and controlling the on-off of the pre-charging switch according to the voltage value comparison result and a clock signal. According to the embodiment provided in the application, the pre-charging efficiency, the safety and the energy saving of the battery system can be improved.

Description

Technical Field

[0001] This invention relates to the field of charging technology, and in particular to a pre-charging circuit and its control method, a battery management system, and an electric vehicle. Background Technology

[0002] With the booming development of new energy electric vehicles, major manufacturers are paying increasing attention to the safety and energy-saving performance of electric vehicle battery systems. Simultaneously, more and more measures are being implemented to improve the system performance and reliability of electric vehicle battery systems, with battery charging technology being a crucial component. Traditional battery systems typically employ a passive pre-charging scheme, which involves setting a pre-charging resistor in the charging circuit to pre-charge the bus capacitor through its current-limiting effect. However, this pre-charging scheme generates significant heat from the pre-charging resistor, affecting its lifespan and potentially causing thermal failure and fire. Furthermore, the heat dissipated by the pre-charging resistor can damage surrounding components, impacting battery system safety; it also increases power consumption, resulting in poor energy-saving performance. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a pre-charging circuit and its control method, a battery management system, and an electric vehicle, which can improve pre-charging efficiency, reduce heat generation during the pre-charging process, reduce power consumption of the battery system, and improve the safety and energy efficiency of the battery system.

[0004] In a first aspect, embodiments of the present invention provide a pre-charging circuit, comprising: a capacitor; a power battery, the positive terminal of which is connected to a first terminal of the capacitor; a pre-charging inductor, the first terminal of which is connected to the first terminal of the capacitor, and the second terminal of which is connected to the second terminal of the capacitor; a pre-charging switch, connected in series between the negative terminal of the power battery and the first terminal of the pre-charging inductor; and a switch control module, the input terminal of which is connected to the negative terminal of the power battery, and the output terminal of which is connected to the pre-charging switch, for acquiring circuit signals in the pre-charging circuit, comparing and processing the circuit signals and a reference signal to obtain a voltage comparison result, and controlling the on / off state of the pre-charging switch according to the voltage comparison result and a clock signal.

[0005] The pre-charging circuit provided by the first aspect of the present invention has at least the following beneficial effects: In the pre-charging circuit, after acquiring the circuit signal in the pre-charging circuit, the switch control module compares the circuit signal and the reference signal to obtain a voltage comparison result. Based on the voltage comparison result and the clock signal, it controls the on / off state of the pre-charging switch. When the pre-charging switch is on, a first current loop is formed to pre-charge the capacitor by the energy released from the power battery; when the pre-charging switch is off, a second current loop is formed to pre-charge the capacitor by the energy released from the pre-charging inductor. According to the scheme of the embodiment of the present invention, the on / off state of the pre-charging switch is controlled by the voltage comparison result and the clock signal, and the first current loop and the second current loop are switched by the pre-charging switch, so that the first current loop and the second current loop alternately pre-charge the capacitor until the voltage value at both ends of the capacitor is the same as the voltage value at both ends of the power battery. Through the scheme of the embodiment of the present invention, the pre-charging efficiency can be improved while ensuring the safety of pre-charging; and by eliminating the use of the pre-charging resistor, the heat generation during the pre-charging process is reduced, the power consumption of the battery system is reduced, and the safety and energy saving of the battery system are improved; the integration of the pre-charging circuit is improved, which is beneficial to the layout of the battery management system.

[0006] According to some embodiments of the present invention, the switch control module includes: a signal detection and amplification module connected in series between the negative terminal of the power battery and the precharge switch, for acquiring the circuit signal, amplifying the circuit signal, and outputting an amplified signal; a comparator, the non-inverting input of the comparator being connected to the output of the signal detection and amplification module, and the inverting input of the comparator being connected to a reference signal source, for receiving and comparing the amplified signal with the reference signal, and outputting a voltage comparison result; and a NOR logic module, the two logic inputs of the NOR logic module being connected to the output of the comparator and the output of the clock generation module, respectively, and the output of the NOR logic module being connected to the precharge switch, for controlling the on / off state of the precharge switch according to the voltage comparison result and the clock signal.

[0007] According to some embodiments of the present invention, the pre-charging circuit further includes: a battery pack main negative switch connected between the negative terminal of the power battery and the second terminal of the capacitor.

[0008] According to some embodiments of the present invention, the pre-charging circuit further includes: a first freewheeling protection module connected between a first terminal of the pre-charging inductor and a first terminal of the capacitor, the first freewheeling protection module being used to freewheel a first current flowing from the first terminal of the pre-charging inductor to the first terminal of the capacitor.

[0009] According to some embodiments of the present invention, the pre-charging circuit further includes: a second freewheeling protection module connected between the pre-charging switch and the first terminal of the pre-charging inductor, the second freewheeling protection module being used to freewheel a second current flowing from the first terminal of the pre-charging inductor to the pre-charging switch.

[0010] According to some embodiments of the present invention, the signal detection and amplification module includes a current detection resistor and a signal amplifier. The current detection resistor is connected in series between the negative terminal of the power battery and the precharge switch, and the signal amplifier is connected in parallel with the current detection resistor.

[0011] In a second aspect, embodiments of the present invention provide a control method for a pre-charging circuit, applied to the pre-charging circuit described in the first aspect. The method includes: acquiring circuit signals in the pre-charging circuit; comparing the circuit signals and a reference signal to obtain a voltage comparison result; controlling the on / off state of a pre-charging switch according to the voltage comparison result and a clock signal, wherein, when the voltage comparison result indicates that the voltage value of the circuit signal is less than a voltage threshold of the reference signal and the clock signal is at a low level, the pre-charging switch is controlled to be turned on to form a first current loop for pre-charging a capacitor by releasing energy from the power battery; when the voltage comparison result indicates that the voltage value of the circuit signal is greater than the voltage threshold of the reference signal, the pre-charging switch is controlled to be turned off to form a second current loop for pre-charging a capacitor by releasing energy from a pre-charging inductor.

[0012] The control method for the pre-charging circuit provided by the second aspect of the present invention has at least the following beneficial effects: when the voltage value comparison result shows that the voltage value of the circuit signal is less than the voltage threshold of the reference signal and the clock signal is at a low level, the pre-charging switch is controlled to be turned on, forming a first current loop for pre-charging the capacitor by the energy released by the power battery; when the voltage value comparison result shows that the voltage value of the circuit signal is greater than the voltage threshold of the reference signal, the pre-charging switch is controlled to be turned off, forming a second current loop for pre-charging the capacitor by the energy released by the pre-charging inductor. According to the scheme of the embodiment of the present invention, the on / off state of the pre-charging switch is controlled by the voltage value comparison result and the clock signal, and the first current loop and the second current loop are switched by the pre-charging switch, so that the first current loop and the second current loop alternately pre-charge the capacitor until the voltage value across the capacitor is the same as the voltage value across the power battery. That is to say, the scheme of the embodiment of the present invention can improve the pre-charging efficiency while ensuring pre-charging safety; and by eliminating the use of the pre-charging resistor, the heat generated during the pre-charging process is reduced, the power consumption of the battery system is reduced, and the safety and energy efficiency of the battery system are improved; the integration of the pre-charging circuit is improved, which is beneficial to the layout of the battery management system.

[0013] According to some embodiments of the present invention, the pre-charging circuit further includes: a battery pack main negative switch connected between the negative terminal of the power battery and the second terminal of the capacitor, and the method further includes: closing the battery pack main negative switch when the voltage value across the capacitor is equal to the voltage value of the power battery to complete the active pre-charging process.

[0014] Thirdly, embodiments of the present invention provide a battery management system, including: a pre-charging circuit as described in the first aspect.

[0015] Fourthly, embodiments of the present invention provide an electric vehicle, including: a battery management system as described in the third aspect.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] Additional aspects and advantages of the invention will become apparent and readily understood in conjunction with the following description of the embodiments, in which:

[0018] Figure 1 This is a schematic diagram of the pre-charging circuit provided in one embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the pre-charging circuit provided in another embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the specific structure of the pre-charging circuit provided in some other embodiments of the present invention;

[0021] Figure 4 A truth table for a NOR logic module provided in one embodiment of the present invention;

[0022] Figure 5 A flowchart illustrating a method for controlling a pre-charging circuit according to an embodiment of the present invention;

[0023] Reference numerals: Power battery 100, capacitor Cx, pre-charge inductor L, pre-charge switch 200, switch control module 300, signal detection and amplification module 310, current detection resistor 311, signal amplifier 312, comparator 320, reference signal source 330, NOR logic module 340, clock generation module 350, battery pack main positive switch K1, battery pack main negative switch K2, first freewheeling protection module 400, first diode D1, second short-circuit protection unit 410, third short-circuit protection unit 420, second freewheeling protection module 500, second diode D2, first short-circuit protection unit 600, drive module 700, active disconnection protection module 800. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0025] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0026] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0027] This invention proposes a pre-charging circuit and its control method, a battery management system, and an electric vehicle. It controls the on / off state of the pre-charging switch based on voltage comparison results and a clock signal. The pre-charging switch switches between a first current loop and a second current loop, allowing the first and second current loops to alternately pre-charge the capacitor until the voltage across the capacitor matches the voltage across the power battery. This invention improves pre-charging efficiency while ensuring pre-charging safety. Furthermore, by eliminating the use of a pre-charging resistor, it reduces heat generation during pre-charging, lowers battery system power consumption, and improves battery system safety and energy efficiency. The increased integration of the pre-charging circuit also facilitates the layout of the battery management system.

[0028] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0029] like Figure 1As shown, this embodiment of the invention provides a pre-charging circuit, including: a capacitor Cx, a power battery 100, a pre-charging inductor L, a pre-charging switch 200, and a switch control module 300. The positive terminal of the power battery 100 is connected to a first terminal of the capacitor Cx; the first terminal of the pre-charging inductor L is connected to a first terminal of the capacitor Cx, and the second terminal of the pre-charging inductor L is connected to a second terminal of the capacitor Cx; the pre-charging switch 200 is connected in series between the negative terminal of the power battery 100 and the first terminal of the pre-charging inductor L; the input terminal of the switch control module 300 is connected to the negative terminal of the power battery 100, and the output terminal of the switch control module 300 is connected to the pre-charging switch 200. The switch control module 300 is used to acquire circuit signals in the pre-charging circuit, compare and process the circuit signals and a reference signal to obtain a voltage comparison result, and control the on / off state of the pre-charging switch based on the voltage comparison result and a clock signal.

[0030] In such Figure 1 In the pre-charging circuit shown, after acquiring the circuit signal in the pre-charging circuit, the switch control module 300 compares the circuit signal and the reference signal to obtain the voltage comparison result. Based on the voltage comparison result and the clock signal, it controls the on / off state of the pre-charging switch 200. When the pre-charging switch 200 is on, a first current loop is formed to pre-charge the capacitor Cx by the energy released by the power battery 100. When the pre-charging switch 200 is off, a second current loop is formed to pre-charge the capacitor Cx by the energy released by the pre-charging inductor L. According to the embodiment of the present invention, the precharge switch 200 is switched on and off by comparing voltage values ​​and using a clock signal. The precharge switch 200 switches between the first current loop and the second current loop, allowing the first current loop and the second current loop to alternately precharge the capacitor Cx until the voltage across the capacitor Cx is the same as the voltage across the power battery 100. This embodiment of the present invention can improve precharge efficiency while ensuring precharge safety; furthermore, by eliminating the use of a precharge resistor, the heat generated during the precharge process is reduced, the power consumption of the battery system is lowered, and the safety and energy efficiency of the battery system are improved; the integration of the precharge circuit is improved, which is beneficial for the layout of the battery management system.

[0031] like Figure 2As shown, according to some embodiments of the present invention, the switch control module 300 includes: a signal detection and amplification module 310, a comparator 320, a reference signal source 330, a NOR logic module 340, and a clock generation module 350. The signal detection and amplification module 310 is connected in series between the negative terminal of the power battery 100 and the pre-charge switch 200, and is used to acquire circuit signals, amplify the circuit signals, and output an amplified signal. The non-inverting input of the comparator 320 is connected to the output of the signal detection and amplification module 310, and the inverting input of the comparator 320 is connected to the reference signal source 330, and is used to receive and compare the amplified signal with the reference signal, and output the voltage comparison result. The two logic inputs of the NOR logic module 340 are respectively connected to the output of the comparator 320 and the output of the clock generation module 350, and the output of the NOR logic module 340 is connected to the pre-charge switch 200, and is used to control the on / off state of the pre-charge switch 200 according to the voltage comparison result and the clock signal.

[0032] In some embodiments, the pre-charging circuit further includes a battery pack main positive switch K1 and a battery pack main negative switch K2. The battery pack main positive switch K1 is connected between the positive terminal of the power battery 100 and the first terminal of the capacitor Cx, and the battery pack main negative switch K2 is connected between the negative terminal of the power battery 100 and the second terminal of the capacitor Cx.

[0033] According to embodiments of the present invention, such as Figure 2In the pre-charging circuit shown, when the main positive switch K1 of the battery pack is closed, firstly, the signal detection and amplification module 310 acquires the circuit signal in the pre-charging circuit, amplifies the circuit signal, outputs an amplified signal, and outputs the amplified signal to the non-inverting input of the comparator 320. The inverting input of the comparator 320 is connected to the reference signal source 330, which outputs a reference signal to the comparator 320. The voltage value of the reference signal is the maximum voltage threshold allowed in the pre-charging circuit. Next, after receiving the amplified signal and the reference signal, the comparator 320 compares the voltage threshold of the amplified signal with that of the reference signal and outputs the voltage comparison result to the NOR logic module 340. Specifically, if the voltage value of the amplified signal is less than the voltage threshold, the comparator 320 outputs a low level (logic value 0) to the NOR logic module 340; if the voltage value of the amplified signal is greater than the voltage threshold, the comparator 320 outputs a high level (logic value 1) to the NOR logic module 340. Then, after the NOR logic module 340 receives the level signal output by the comparator 320, that is, after receiving the voltage comparison result, the NOR logic module 340 controls the opening and closing of the precharge switch 200 according to the voltage comparison result and the clock signal. Specifically, when the NOR logic module 340 receives a low level output from the comparator 320 (that is, the voltage value of the amplified signal is less than the voltage threshold) and the clock signal is low, the NOR logic module 340 outputs a high level (logic value 1). The high level signal controls the precharge switch 200 to close and conduct, forming a first current loop for precharging the capacitor Cx by the energy released by the power battery 100. When the NOR logic module 340 receives a high level output from the comparator 320 (that is, the voltage value of the amplified signal is greater than the voltage threshold), regardless of whether the clock signal outputs a high level or a low level, the NOR logic module 340 outputs a low level (logic value 0). The low level signal controls the precharge switch 200 to open, forming a second current loop for precharging the capacitor Cx by the energy released by the precharge inductor L. According to the embodiment of the present invention, the pre-charge switch 200 is switched on and off by comparing voltage values ​​and using a clock signal. The pre-charge switch 200 switches between the first current loop and the second current loop, allowing the first and second current loops to alternately pre-charge the capacitor Cx until the voltage across the capacitor Cx is the same as the voltage across the power battery 100. In other words, the solution of this embodiment of the present invention can improve pre-charge efficiency while ensuring pre-charge safety; furthermore, by eliminating the use of a pre-charge resistor, heat generation during pre-charge is reduced, lowering the power consumption of the battery system and improving the safety and energy efficiency of the battery system; and the integration of the pre-charge circuit is improved, which is beneficial for the layout of the battery management system.

[0034] Specifically, the main positive switch K1 of the battery pack is a main positive relay of the battery pack. The main positive switch K1 of the battery pack can be controlled by the battery management system. Under the control of the battery management system, the main positive switch K1 of the battery pack can be closed to conduct the circuit between the positive terminal of the power battery 100 and the first terminal of the capacitor Cx.

[0035] It will be understood by those skilled in the art that Figure 1 and Figure 2 The schematic diagram of the pre-charging circuit shown does not constitute a limitation on the embodiments of the present invention. It may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0036] It should be noted that the two logic inputs of the NOR logic module 340 are connected to the outputs of the comparator 320 and the clock generator module 350, respectively, and the output of the NOR logic module 340 is connected to the precharge switch 200. The comparator 320 outputs a logic value (1 or 0) representing the voltage comparison result. The clock generator module 350 outputs a clock signal that periodically changes between high and low levels (i.e., between 1 and 0). After the logic operation of the NOR logic module 340, the NOR logic module 340 outputs a logic value of 1 or 0, controlling the on / off state of the precharge switch 200.

[0037] Specifically, such as Figure 4 As shown, Figure 4An embodiment of the present invention provides a truth table for an NOR logic module; A represents the level value of the clock signal output by the clock generation module 350, A=1 indicates that the clock generation module 350 outputs a high level, and A=0 indicates that the clock generation module 350 outputs a low level; B represents the logic value output by the comparator 320 representing the voltage comparison result; and Y represents the logic value output by the NOR logic module 340. Y=1 if and only if A=0 and B=0; when B=1, Y is always equal to 0 regardless of whether A=0 or A=1. That is, when the voltage value of the amplified signal is less than the voltage threshold and the clock signal output is low, the NOR logic module 340 controls the precharge switch 200 to turn on; when the voltage value of the amplified signal is less than the voltage threshold and the clock signal output is high, the NOR logic module 340 controls the precharge switch 200 to turn off. When the voltage value of the amplified signal is less than the voltage threshold, the periodic clock signal makes the on / off state of the precharge switch 200 periodic. The average current and inductor current ripple are the same in each switching cycle, and the capacitor voltage increases linearly, which helps improve system stability. Furthermore, when the voltage value of the amplified signal is greater than the voltage threshold, regardless of whether the clock signal output is high or low, or if the logic module 340 controls the precharge switch 200 to open, it ensures that the current loop in the active precharge circuit is less than the preset maximum precharge current, thereby reducing heat generation during the precharge process, lowering battery system power consumption, and improving battery system safety and energy efficiency.

[0038] It should be noted that the clock generation module 350 outputs a clock signal with a fixed frequency, which is between 10kHz and 60kHz.

[0039] Reference Figure 2 and Figure 3Specifically, the precharge switch 200 uses a metal-oxide-semiconductor field-effect transistor, i.e., a MOSFET. The drain of the MOSFET is connected to the first terminal of the precharge inductor L, the source of the MOSFET is connected to the negative terminal of the power battery 100 through the signal detection and amplification module 310, and the gate of the MOSFET is connected to the output terminal of the NOR logic module 340 through the drive module 700. The precharge switch 200 is turned on or off under the control of the NOR logic module 340. When the precharge switch 200 is on, a first current loop is formed, in which the power battery 100 releases energy to precharge the capacitor Cx. The current in the first current loop has a first direction, flowing sequentially from the positive terminal of the power battery 100 to the capacitor Cx, the precharge inductor L, the precharge switch 200, the signal detection and amplification module 310, and the negative terminal of the power battery 100. When the precharge switch 200 is off, a second current loop is formed, in which the precharge inductor L releases energy to precharge the capacitor Cx. The current in the second current loop has a second direction, flowing sequentially from the first end of the precharge inductor L through the capacitor Cx and the second end of the precharge inductor L. By switching the first and second current loops on and off, the first and second current loops alternately precharge the capacitor Cx until the voltage across the capacitor Cx is the same as the voltage across the power battery 100. It can be understood that the voltage output across the power battery 100 is Vbat.

[0040] It should be noted that the first current loop is the current loop in which the power battery 100 precharges the capacitor Cx when the precharge switch 200 is turned on during the precharge process. During the precharge process of the capacitor Cx, the precharge inductor L will also be charged.

[0041] It should be noted that the second current loop is a current loop formed by the inductor's self-inductance effect when the precharge switch 200 is opened during the precharge process. It is an energy release loop formed by the energy release of the precharge inductor L. The inductance value of the precharge inductor L should be reasonably determined. If the inductance value of the precharge inductor L is too small, the inductor may saturate due to the switching delay, leading to overcurrent and burnout of the device. If the inductance value of the precharge inductor L is too large, the size of the precharge inductor L will be large, increasing the space occupied by the precharge circuit and the manufacturing cost. This invention does not impose specific restrictions on the inductance value of the precharge inductor L; the inductance value can be designed according to the actual situation.

[0042] Reference Figure 3 According to some embodiments of the present invention, the active pre-charge protection circuit further includes a first short-circuit protection unit 600 connected in series between the second terminal of the pre-charge inductor L and the second terminal of the capacitor Cx. The first short-circuit protection unit 600 is used to disconnect the line in time in the event of a short circuit to protect the circuit and components.

[0043] Reference Figures 2 to 3According to some embodiments of the present invention, the pre-charging circuit further includes a battery pack main negative switch K2 connected between the negative terminal of the power battery 100 and the second terminal of the capacitor Cx. Specifically, the battery pack main negative switch K2 is a battery pack main negative relay. The battery pack main negative switch K2 is controlled by the battery management system, and can be closed under the control of the battery management system to conduct the circuit between the negative terminal of the power battery 100 and the second terminal of the capacitor Cx. When the voltage value across the capacitor Cx is equal to the voltage value of the power battery 100, the battery pack main negative switch K2 closes under the control of the battery management system, completing the active pre-charging process and forming a complete charging path for the power battery 100.

[0044] Reference Figures 2 to 3 According to some embodiments of the present invention, the pre-charging circuit further includes a first freewheeling protection module 400 connected between a first terminal of the pre-charging inductor L and a first terminal of the capacitor Cx. The first freewheeling protection module 400 is used to freewheel the first current flowing from the first terminal of the pre-charging inductor L to the first terminal of the capacitor Cx. Specifically, the first freewheeling protection module 400 includes a first diode D1, a second short-circuit protection unit 410, and a third short-circuit protection unit 420. The anode of the first diode D1 is connected to the first terminal of the pre-charging inductor L, and the cathode of the first diode D1 is connected to the first terminal of the capacitor Cx through the second short-circuit protection unit 410 and the third short-circuit protection unit 420 connected in series. Both the second short-circuit protection unit 410 and the third short-circuit protection unit 420 are used to disconnect the line in time to protect the circuit and components in the event of a short circuit. The direction of current flowing from the first terminal of the pre-charging inductor L to the first terminal of the capacitor Cx is the conduction direction of the first diode D1, and the first diode D1 is used to freewheel the current in the second current loop. In addition, the pre-charging circuit also includes an active disconnection protection module 800 connected between the power battery 100 and the main positive switch K1 of the battery pack. The active disconnection protection module 800 is used to actively disconnect the circuit when the current is too high, thereby protecting the power battery 100 and further improving the safety of the pre-charging circuit. Specifically, the active disconnection protection module 800 uses an active disconnection protection fuse.

[0045] It is understood that multiple short-circuit protection units can be set in the pre-charging circuit according to actual needs, and the present invention does not impose specific limitations on this.

[0046] Reference Figure 2 and Figure 3According to some embodiments of the present invention, the pre-charging circuit further includes a second freewheeling protection module 500 connected between the pre-charging switch 200 and the first terminal of the pre-charging inductor L. The second freewheeling protection module 500 is used to freewheel the second current flowing from the first terminal of the pre-charging inductor L to the pre-charging switch 200. The second freewheeling protection module 500 includes a second diode D2, the anode of the second diode D2 is connected to the first terminal of the pre-charging inductor L, and the cathode of the second diode D2 is connected to the pre-charging switch 200. The direction in which the current flows from the first terminal of the pre-charging inductor L to the pre-charging switch 200 is the conduction direction of the second diode D2, and the second diode D2 is used to freewheel the current in the first current loop.

[0047] Reference Figure 2 and Figure 3 According to some embodiments of the present invention, the signal detection and amplification module 310 includes a current detection resistor 311 and a signal amplifier 312. The current detection resistor 311 is connected in series between the negative terminal of the power battery 100 and the pre-charge switch 200, and the signal amplifier 312 is connected in parallel with the current detection resistor 311. When the main positive switch K1 of the battery pack is closed, there is a current signal I in the first current loop. After the signal detection and amplification module 310 detects and amplifies the current signal, an amplified signal is obtained. The voltage of the amplified signal is V = I*R*G, where R is the resistance value of the current detection resistor 311 and G is the amplification factor of the signal amplifier 312. The comparator 320 compares the voltage value of the amplified signal with the voltage threshold Vref of the reference voltage output by the reference signal source 330 and outputs the voltage comparison result. Therefore, the maximum inductor current allowed to pass through the circuit can be set to Imax = Vref / (R*G) by using the voltage threshold Vref and the amplification factor G of the signal amplifier 312. It is understood that the present invention does not impose specific restrictions on the amplification factor G of the signal amplifier 312 and the resistance value R of the current detection resistor 311, which can be determined according to the actual circuit design requirements.

[0048] Reference Figure 2 and Figure 3 According to some embodiments of the present invention, the precharge circuit further includes a drive module 700 connected between the NOR logic module 340 and the precharge switch 200. Specifically, the drive module 700 is used to drive the precharge switch 200 to be turned on or off under the control of the NOR logic module 340.

[0049] Reference Figure 5 , Figure 5 This is a flowchart illustrating a control method for a pre-charging circuit according to an embodiment of the present invention. This control method for the pre-charging circuit is applied to... Figure 1 The pre-charging circuit shown in this embodiment of the invention includes, but is not limited to, steps S510 to S530.

[0050] Step S510: Obtain the circuit signals in the pre-charging circuit.

[0051] Step S520: Compare and process the circuit signal and the reference signal to obtain the voltage value comparison result.

[0052] Step S530: Control the on / off state of the precharge switch according to the voltage comparison result and the clock signal. Specifically, when the voltage comparison result shows that the voltage value of the circuit signal is less than the voltage threshold of the reference signal and the clock signal is at a low level, control the precharge switch to be turned on to form a first current loop for precharging the capacitor by releasing energy from the power battery. When the voltage comparison result shows that the voltage value of the circuit signal is greater than the voltage threshold of the reference signal, control the precharge switch to be turned off to form a second current loop for precharging the capacitor by releasing energy from the precharge inductor.

[0053] Through steps S510 to S530, in the pre-charging circuit, when the voltage comparison result shows that the circuit signal voltage is less than the voltage threshold and the clock signal is low, the pre-charging switch 200 is turned on to form a first current loop for pre-charging capacitor Cx by the power battery 100 releasing energy; when the voltage comparison result shows that the circuit signal voltage is greater than the voltage threshold, the pre-charging switch 200 is turned off to form a second current loop for pre-charging capacitor Cx by the pre-charging inductor L releasing energy. According to the embodiment of the present invention, the pre-charging switch 200 is turned on and off by controlling the voltage comparison result and the clock signal, and the first current loop and the second current loop are switched by the pre-charging switch 200, so that the first current loop and the second current loop alternately pre-charge capacitor Cx until the voltage value across capacitor Cx is the same as the voltage value across power battery 100. That is to say, the solution of the embodiment of the present invention can improve pre-charging efficiency, reduce heat generation during pre-charging, reduce power consumption of the battery system, and improve the safety and energy efficiency of the battery system.

[0054] According to some embodiments of the present invention, the pre-charging circuit further includes a battery pack main negative switch K2 connected between the negative terminal of the power battery 100 and the second terminal of the capacitor Cx. The method further includes closing the battery pack main negative switch K2 when the voltage across the capacitor Cx is equal to the voltage of the power battery 100, thereby completing the active pre-charging process. Specifically, when the voltage across the capacitor Cx is equal to the voltage of the power battery 100, the battery pack main negative switch K2 and the battery pack main positive switch K1 are closed, forming a complete charging path for the power battery 100.

[0055] According to some embodiments of the present invention, step S520: comparing the circuit signal and the reference signal to obtain the voltage value comparison result includes: acquiring the circuit signal; amplifying the circuit signal to output an amplified signal; comparing the amplified signal with the reference signal to output the voltage value comparison result; and controlling the on / off state of the precharge switch according to the voltage value comparison result and the clock signal.

[0056] In addition, embodiments of the present invention provide a battery management system, including: Figure 1 The pre-charging circuit is shown. It is understood that the battery management system includes a control unit, which controls the closing and opening of the battery pack main negative switch K2 and the battery pack main positive switch K1. Specifically, during battery management system operation, the pre-charging circuit controls the on / off state of the pre-charging switch 200 based on voltage value comparison results and a clock signal. The pre-charging switch 200 switches between the first current loop and the second current loop, causing the first and second current loops to alternately pre-charge the capacitor Cx until the voltage across the capacitor Cx is the same as the voltage across the power battery 100. Through the solution of this embodiment, pre-charging safety is ensured while improving pre-charging efficiency; furthermore, by eliminating the use of a pre-charging resistor, heat generation during pre-charging is reduced, lowering the power consumption of the battery system and improving the safety and energy efficiency of the battery system; the integration of the pre-charging circuit is improved, which is beneficial for the layout of the battery management system.

[0057] Furthermore, embodiments of the present invention provide an electric vehicle, including a battery management system. The battery management system includes, for example,... Figure 1The pre-charging circuit is shown. It is understood that the electric vehicle also includes a main controller. Specifically, when the electric vehicle requires the battery management system to operate, the main controller sends a command to the battery management system to close the main positive switch K1 of the battery pack, i.e., to close P+Relay. After the main positive switch K1 is closed, the pre-charging circuit operates to pre-charge the capacitor Cx. The signal detection and amplification module 310 acquires the circuit signal, amplifies the circuit signal to obtain an amplified signal, and outputs the amplified signal to the non-inverting input of the comparator 320. The comparator 320 compares the voltage value of the amplified signal with the voltage threshold of the reference signal and outputs the voltage comparison result to the NOR logic module 340. The NOR logic module 340 controls the on / off state of the precharge switch 200 according to the voltage comparison result and the clock signal. When the voltage comparison result shows that the voltage value of the amplified signal is less than the voltage threshold and the clock signal is low, the precharge switch 200 is turned on to form a first current loop for precharging the capacitor Cx by releasing energy from the power battery 100. When the voltage comparison result shows that the voltage value of the amplified signal is greater than the voltage threshold, the precharge switch 200 is turned off to form a second current loop for precharging the capacitor Cx by releasing energy from the precharge inductor L. According to the embodiment of the present invention, the pre-charge switch 200 is switched on and off by comparing voltage values ​​and using a clock signal. The pre-charge switch 200 switches between the first current loop and the second current loop, allowing the first and second current loops to alternately pre-charge the capacitor Cx until the voltage across the capacitor Cx is the same as the voltage across the power battery 100, thus completing the pre-charging process for the capacitor Cx. After completing the pre-charging process for the capacitor Cx, the main controller of the electric vehicle sends a command to the battery management system to close the main negative switch K2 of the battery pack, thereby closing the main negative switch K2 and forming a complete charging path for the power battery 100. Through the embodiment of the present invention, the alternating pre-charging of the capacitor Cx by the first and second current loops ensures pre-charging safety while improving pre-charging efficiency. By eliminating the use of a pre-charging resistor, heat generation during the pre-charging process is reduced, lowering the power consumption of the battery system and improving the safety and energy efficiency of the battery system. Furthermore, the integration of the pre-charging circuit is improved, facilitating a simpler overall vehicle assembly for the battery management system and the electric vehicle.

[0058] In one embodiment, when the electric vehicle requires the battery management system to operate, the main controller of the electric vehicle sends a battery pack main positive switch closing command to the battery management system. The battery management system closes the battery pack main positive switch K1 according to the battery pack main positive switch closing command, and the pre-charging circuit pre-charges the capacitor Cx.

[0059] Next, combined Figure 4 The truth table of the NOR logic module 340 shown and Figure 3 The pre-charging circuit diagram shown further illustrates the pre-charging steps.

[0060] First, when the main positive switch K1 of the battery pack is closed, the current I in the pre-charge circuit is 0, and the voltage after detection and amplification by the signal detection and amplification module 310 is 0. Therefore, the comparator 320 compares the voltage amplified by the signal detection and amplification module 310 with the output voltage of the reference signal source 330 and outputs a low level.

[0061] Secondly, the clock generation module 350 outputs a clock signal of a fixed frequency. The clock signal and the signal output by the comparator 320 are input together to the NOR logic module 340. When the clock generation module 350 outputs 0 and the comparator 320 outputs 0, the NOR logic module 340 outputs 1. When the NOR logic module 340 outputs 1, it controls the precharge switch 200 to close, the inductor current of the precharge inductor L increases, and the output voltage of the signal detection amplification module 310 also increases. The current loop in the precharge circuit is the first current loop for the power battery 100 to release energy to precharge the capacitor Cx.

[0062] Then, when the output voltage of the signal detection and amplification module 310 increases to a level greater than the output voltage of the reference signal source 330, the comparator 320 outputs a high level. Regardless of whether the clock generation module 350 outputs a high or low level, the NOR logic module 340 outputs 0. When the NOR logic module 340 outputs 0, the precharge switch 200 is opened, the inductor current of the precharge inductor L decreases, and the output voltage of the signal detection and amplification module 310 becomes 0. The current loop in the precharge circuit is a second current loop that precharges the capacitor Cx by releasing energy from the precharge inductor L.

[0063] Furthermore, when the clock generation module 350 outputs 1, the comparator 320 outputs 0, or the NOT logic module 340 outputs 0, the control precharge switch 200 remains open, the inductor current of the precharge inductor L decreases, the output voltage of the signal detection amplification module 310 becomes 0, and the current loop in the precharge circuit has not yet been the second current loop that releases energy from the precharge inductor L to precharge the capacitor Cx.

[0064] Subsequently, after time T / 2, when the clock generation module 350 outputs 0, the comparator 320 outputs 0, and the NOR logic module 340 outputs 1, the precharge switch 200 is closed and turned on. The inductor current of the precharge inductor L increases, and the output voltage of the signal detection and amplification module 310 also increases. The current loop in the precharge circuit is switched to the first current loop for precharging the capacitor Cx by the power battery 100 releasing energy. By controlling the opening and closing of the precharge switch 200, the first current loop and the second current loop alternately charge the capacitor Cx until the voltage of the capacitor Cx reaches the output voltage value Vbat of the power battery.

[0065] Finally, when the voltage of capacitor Cx reaches Vbat, it indicates that the pre-charging is complete. At this time, the electric vehicle sends a command to the battery management system to close the main and negative switches of the battery pack. The battery management system closes the main and negative switches of the battery pack K2 according to the command, thus forming a complete charging path for the power battery.

[0066] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the present invention.

Claims

1. A pre-charging circuit, characterized in that, include: Capacitor; A power battery, wherein the positive terminal of the power battery is connected to the first end of the capacitor; A pre-charge inductor, wherein a first terminal of the pre-charge inductor is connected to a first terminal of the capacitor, and a second terminal of the pre-charge inductor is connected to a second terminal of the capacitor; A pre-charge switch is connected in series between the negative terminal of the power battery and the first terminal of the pre-charge sensor; A switch control module is provided, with its input connected to the negative terminal of the power battery and its output connected to the precharge switch. The module acquires circuit signals in the precharge circuit, compares these signals with a reference signal to obtain a voltage comparison result, and controls the on / off state of the precharge switch based on the voltage comparison result and a clock signal. The reference signal is output from a reference signal source within the switch control module, and its voltage value is the maximum allowable voltage threshold in the precharge circuit. When the voltage comparison result indicates that the voltage value of the circuit signal is less than the voltage threshold of the reference signal and the clock signal is low, the precharge switch is turned on, forming a first current loop for precharging the capacitor using energy released from the power battery. When the voltage comparison result indicates that the voltage value of the circuit signal is greater than the voltage threshold of the reference signal, the precharge switch is turned off, forming a second current loop for precharging the capacitor using energy released from the precharge inductor.

2. The pre-charging circuit according to claim 1, characterized in that, The switch control module includes: A signal detection and amplification module is connected in series between the negative terminal of the power battery and the precharge switch. It is used to acquire the circuit signal, amplify the circuit signal, and output an amplified signal. The comparator has its non-inverting input connected to the output of the signal detection and amplification module, and its inverting input connected to a reference signal source. It is used to receive and compare the amplified signal with the reference signal and output the voltage comparison result. The NOR logic module has two logic inputs connected to the output of the comparator and the output of the clock generator module, respectively. The output of the NOR logic module is connected to the precharge switch and is used to control the on / off state of the precharge switch according to the voltage comparison result and the clock signal.

3. The pre-charging circuit according to claim 1, characterized in that, Also includes: A main negative switch for the battery pack connected between the negative terminal of the power battery and the second terminal of the capacitor.

4. The pre-charging circuit according to claim 1, characterized in that, Also includes: A first freewheeling protection module is connected between the first terminal of the precharge inductor and the first terminal of the capacitor. The first freewheeling protection module is used to freewheel the first current flowing from the first terminal of the precharge inductor to the first terminal of the capacitor.

5. The pre-charging circuit according to claim 4, characterized in that, Also includes: A second freewheeling protection module is connected between the precharge switch and the first terminal of the precharge inductor. The second freewheeling protection module is used to freewheel the second current flowing from the first terminal of the precharge inductor to the precharge switch.

6. The pre-charging circuit according to claim 2, characterized in that, The signal detection and amplification module includes a current detection resistor and a signal amplifier. The current detection resistor is connected in series between the negative terminal of the power battery and the pre-charge switch, and the signal amplifier is connected in parallel with the current detection resistor.

7. A control method for a pre-charging circuit, characterized in that, Applied to the pre-charging circuit of claim 1, the method includes: Obtain the circuit signals in the pre-charging circuit; The voltage value comparison result is obtained by comparing the circuit signal and the reference signal. The precharge switch is controlled to open and close based on the voltage comparison result and the clock signal. Specifically, when the voltage comparison result indicates that the voltage value of the circuit signal is less than the voltage threshold of the reference signal and the clock signal is at a low level, the precharge switch is turned on to form a first current loop for precharging the capacitor by releasing energy from the power battery. When the voltage comparison result indicates that the voltage value of the circuit signal is greater than the voltage threshold of the reference signal, the precharge switch is turned off to form a second current loop for precharging the capacitor by releasing energy from the precharge inductor.

8. The control method for the pre-charging circuit according to claim 7, characterized in that, The pre-charging circuit further includes: a battery pack main negative switch connected between the negative terminal of the power battery and the second terminal of the capacitor; the method further includes: When the voltage across the capacitor is equal to the voltage of the power battery, the main negative switch of the battery pack is closed to complete the active pre-charging process.

9. A battery management system, characterized in that, include: The pre-charging circuit as described in any one of claims 1 to 6.

10. An electric vehicle, characterized in that, include: The battery management system as described in claim 9.

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