Current limiting unit type selection method, device and equipment and computer readable storage medium

Abstract

The invention discloses a current limiting unit type selection method, device and equipment and a computer readable storage medium, relates to the technical field of power batteries, and discloses the current limiting unit type selection method, device and equipment and the computer readable storage medium. Capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information are determined according to the pre-charging loop voltage; determining a resistance target value and a rated power target value of a current limiting unit according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information; and based on the resistance target value and the rated power target value of the current limiting unit, selecting a target current limiting unit to control the power battery to perform pre-charging. The resistance target value and the rated power target value of the current limiting unit are calculated, and the target current limiting unit is selected, so that high-voltage electrical components are prevented from being impacted by instant large current, and safe operation and stability of the power battery are guaranteed.

Description

Technical Field

[0001] The present application relates to the field of power battery technology, and in particular to a current limiting unit selection method, device, equipment and computer-readable storage medium. Background Art

[0002] In the field of power batteries, the power battery system is an important energy source system for hybrid vehicles and electric vehicles, providing electric energy for the vehicle during driving. However, the voltage of the power battery system is high voltage relative to the whole vehicle. In order to avoid the generation of instantaneous large current during the high-voltage power-on process of the whole vehicle, impacting high-voltage electrical components, causing related relays or contactors in the high-voltage system circuit to stick and high-voltage device damage, etc., it is necessary to design a pre-charging circuit to pre-charge the capacitor unit and use the current limiting effect of the pre-charging resistor to achieve safe connection of the high-voltage circuit. Therefore, choosing a suitable current limiting unit is a must.

[0003] At present, the existing technology adds pre-charging resistors to the electric vehicle power system. The design of the pre-charging circuit is usually based on a simplified RC equivalent circuit model, which includes at least a power battery, a relay, a pre-charging resistor and a capacitor unit. At the beginning of power-on, the capacitor unit needs to be pre-charged to reduce the impact current during power-on and protect the motor control machine, relays and other devices, thereby ensuring the safe operation of the power battery system.

[0004] However, the existing technology often relies on experience when selecting the current limiting unit, lacks accurate calculation methods, and the selection of the current limiting unit is not accurate enough. Due to the lack of a comprehensive evaluation of the performance of the current limiting unit under actual working conditions, including its instantaneous power carrying capacity, pulse tolerance, and thermal stability under different ambient temperatures, it is impossible to ensure that the current limiting unit can work safely and effectively under all circumstances. In addition, the existing technology fails to fully consider the thermal capacity and temperature rise of the current limiting unit, which will cause the current limiting unit to overheat or even be damaged under continuous pulses or extreme environmental conditions, thereby affecting the safe operation and reliability of the entire power battery system. Therefore, how to accurately select the current limiting unit is a technical problem that needs to be solved urgently.

[0005] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention

[0006] The main purpose of the present application is to provide a current limiting unit selection method, device, equipment and computer-readable storage medium, aiming to solve the technical problem of how to accurately select a current limiting unit.

[0007] To achieve the above-mentioned purpose, the present application proposes a current limiting unit selection method, which is applied to a pre-charging circuit, the pre-charging circuit comprising a power battery, a main positive relay, a main negative relay, a pre-charging relay, a current limiting unit, a capacitor unit and a load unit, the positive electrode of the power battery is connected to the first end of the main positive relay and the first end of the pre-charging relay, the second end of the pre-charging relay is connected to the first end of the current limiting unit, the second end of the main positive relay is connected to the second end of the current limiting unit, the first end of the capacitor unit and the first end of the load unit, the second end of the capacitor unit and the second end of the load unit are both connected to the first end of the main negative relay, and the second end of the main negative relay is connected to the negative electrode of the power battery, the method comprising:

[0008] Detecting a pre-charge loop voltage, and determining capacitor unit characteristic information, pre-charge characteristic information, and pulse characteristic information according to the pre-charge loop voltage;

[0009] Determine the current limiting unit resistance target value and the rated power target value according to the pre-charge loop voltage, the capacitor unit characteristic information, the pre-charge characteristic information and the pulse characteristic information;

[0010] Based on the target value of the current limiting unit resistance and the target value of the rated power, a target current limiting unit is selected to control the power battery for pre-charging.

[0011] In one embodiment, the step of determining the capacitor unit characteristic information, the pre-charge characteristic information and the pulse characteristic information according to the pre-charge loop voltage includes:

[0012] Determine the capacitor unit terminal voltage, the capacitor unit initial voltage, the capacitor unit capacitance, the power battery system terminal voltage, the pre-charge relay rated current, the pre-charge circuit current, the resistance working condition information, the pre-charge time, the pulse frequency, and the pulse interval time according to the pre-charge circuit voltage;

[0013] Determine the characteristic information of the capacitor unit based on the voltage at the capacitor unit terminal, the initial voltage of the capacitor unit, and the capacitance value of the capacitor unit;

[0014] Determine pre-charging characteristic information based on the power battery system terminal voltage, the pre-charging relay rated current, the pre-charging loop current, the resistance operating condition information, and the pre-charging time;

[0015] The pulse characteristic information is determined based on the pulse frequency and pulse interval time.

[0016] In one embodiment, the step of determining the current limiting unit resistance target value and the rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information includes:

[0017] Determine a startup safety resistance value and a current balance resistance value based on the pre-charge loop voltage, the pre-charge characteristic information, and the capacitor unit characteristic information;

[0018] Determine the pulse energy resistance value, the rated power characteristic value, the power overload resistance value and the thermal stability resistance value based on the pre-charge loop voltage, the pre-charge characteristic information and the pulse characteristic information;

[0019] The current limiting unit resistance target value and the rated power target value are obtained based on the pre-charge loop voltage, startup safety resistance value, current balance resistance value, pulse energy resistance value, rated power characteristic value, power overload resistance value and thermal stability resistance value.

[0020] In one embodiment, the step of determining the startup safety resistance value and the current balance resistance value based on the pre-charge loop voltage, the pre-charge characteristic information, and the capacitor unit characteristic information includes:

[0021] Constructing a first loop model based on the pre-charge loop voltage, the pre-charge characteristic information, and the capacitor unit characteristic information;

[0022] Building a second loop model based on the pre-charge loop voltage and pre-charge characteristic information;

[0023] Calculate the starting safety resistance value based on the resistance operating condition information and the power battery system terminal voltage in the pre-charge characteristic information, the capacitor unit terminal voltage, the capacitor unit initial voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, and the first circuit model;

[0024] The current balancing resistance value is calculated based on the resistance operating condition information in the pre-charging characteristic information, the power battery system terminal voltage, the pre-charging relay rated current and the second loop model.

[0025] In one embodiment, the step of determining the pulse energy resistance value, the rated power characteristic value, the power overload resistance value, and the thermal stability resistance value based on the pre-charge loop voltage, the pre-charge characteristic information, and the pulse characteristic information includes:

[0026] Obtain the instantaneous terminal voltage of the current limiting unit, the peak energy of the current limiting unit, the mass of the current limiting unit, the specific heat capacity of the current limiting unit material, the power safety factor, the power overload factor, the target temperature of the current limiting unit, the initial temperature of the current limiting unit, and the operating temperature limit of the current limiting unit;

[0027] Determining characteristic information of the current limiting unit based on the instantaneous terminal voltage of the current limiting unit, the peak energy of the current limiting unit, the mass of the current limiting unit, the specific heat capacity of the material of the current limiting unit, the power safety factor, and the power overload factor;

[0028] Determine the current limiting unit temperature characteristic information based on the current limiting unit target temperature, the current limiting unit initial temperature and the current limiting unit operating temperature limit;

[0029] Constructing a third loop model, a fourth loop model and a fifth loop model based on the pre-charge characteristic information, the pulse characteristic information, the current limiting unit characteristic information and the current limiting unit temperature characteristic information;

[0030] Calculate the pulse energy resistance value based on the power battery system terminal voltage, pre-charging loop current, pre-charging time in the pre-charging characteristic information, the capacitor unit terminal voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, the pulse frequency, the pulse interval time in the pulse characteristic information, the current limiting unit instantaneous terminal voltage, the current limiting unit peak energy in the current limiting unit characteristic information, and the third loop model;

[0031] Calculate the rated power characteristic value and the power overload resistance value based on the resistance operating condition information in the pre-charge characteristic information, the power battery system terminal voltage and the power safety factor and the power overload factor in the current limiting unit characteristic information and the fourth loop model;

[0032] The thermal stability resistance value is calculated based on the power battery system terminal voltage in the pre-charging characteristic information, the pre-charging time and the instantaneous terminal voltage of the current limiting unit in the current limiting unit characteristic information, the current limiting unit mass, the specific heat capacity of the current limiting unit material, the current limiting unit target temperature in the current limiting unit temperature characteristic information, the current limiting unit initial temperature, the current limiting unit operating temperature limit and the fifth loop model.

[0033] In one embodiment, the method further comprises:

[0034] Calculate energy information based on the power battery system terminal voltage, pre-charge loop current, pre-charge time in the pre-charge characteristic information, the capacitor unit terminal voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, the pulse frequency, and the pulse interval time in the pulse characteristic information, where the energy information includes the power battery supply energy and the capacitor unit storage energy;

[0035] Calculate the pulse energy of the pre-charge circuit based on the energy supplied by the power battery and the energy stored in the capacitor unit;

[0036] Determine the energy absorption state based on the pre-charging circuit pulse energy and the current limiting unit peak energy in the current limiting unit characteristic information, and obtain the determination result;

[0037] The pulse energy resistance value is selected and determined based on the judgment result.

[0038] In one embodiment, the method further comprises:

[0039] Determine the peak power of the current limiting unit based on the power battery system terminal voltage and resistance operating condition information in the pre-charge characteristic information;

[0040] Determine the rated power characteristic value based on the power safety factor, the power overload factor, and the peak power of the current limiting unit in the characteristic information of the current limiting unit;

[0041] Determine the power overload state based on the rated power characteristic value and the power safety factor and the power overload factor in the characteristic information of the current limiting unit, and obtain the determination result;

[0042] The power overload resistance value is selected and determined based on the judgment result.

[0043] In addition, to achieve the above-mentioned purpose, the present application also proposes a current limiting unit selection device, which includes:

[0044] An acquisition module is used to detect the pre-charging loop voltage and determine the capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information according to the pre-charging loop voltage;

[0045] A processing module, used to determine a current limiting unit resistance target value and a rated power target value according to a pre-charging loop voltage, capacitor unit characteristic information, pre-charging characteristic information, and pulse characteristic information;

[0046] The execution module is used to select a target current limiting unit to control the power battery for pre-charging based on the target value of the current limiting unit resistance and the target value of the rated power.

[0047] In addition, to achieve the above objectives, the present application also proposes a current limiting unit selection device, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the current limiting unit selection method as described above.

[0048] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the current limiting unit selection method as described above are implemented.

[0049] One or more technical solutions proposed in this application have at least the following technical effects:

[0050] The present application proposes a method for selecting a current limiting unit, which detects the pre-charging circuit voltage, and determines the capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information according to the pre-charging circuit voltage; determines the current limiting unit resistance target value and the rated power target value according to the pre-charging circuit voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information; based on the current limiting unit resistance target value and the rated power target value, selects a target current limiting unit to control the power battery for pre-charging. The present application detects the pre-charging circuit voltage of the power battery system, and calculates the current limiting unit resistance target value and the rated power target value in combination with the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information, and selects a target current limiting unit, thereby ensuring the safety of the current during the pre-charging process, avoiding the impact of instantaneous large current on high-voltage electrical components, and optimizing the energy conversion and storage process, reducing energy loss, thereby ensuring the safe operation and long-term stability of the power battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0052] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0053] Figure 1 A schematic diagram of a flow chart provided for the first embodiment of the method for selecting a current limiting unit of the present application;

[0054] Figure 2 This is a RC equivalent circuit model diagram of the pre-charging circuit composed of the current limiting unit selection method of this application;

[0055] Figure 3 This is a curve diagram of voltage and current changes during the pre-charging process in the first embodiment of the current limiting unit selection method of the present application;

[0056] Figure 4 This is a schematic diagram of pulse characteristic information in the first embodiment of the current limiting unit selection method of the present application;

[0057] Figure 5 A schematic diagram of a flow chart provided for the second embodiment of the method for selecting a current limiting unit of the present application;

[0058] Figure 6 This is a schematic diagram of the module structure of the current limiting unit selection device according to an embodiment of the present application;

[0059] Figure 7Schematic diagram of the equipment structure of the hardware operating environment involved in the method for selecting a current limiting unit in an embodiment of the present application.

[0060] Description of Figure Numbers:

[0061] 10. Power battery; 20. Capacitor unit; 30. Load unit; K1. Main positive relay; K2. Main negative relay; K3. Pre-charge relay; R. Current limiting unit.

[0062] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0063] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0064] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0065] The main solution of the embodiment of the present application is: detect the pre-charging loop voltage, and determine the capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information according to the pre-charging loop voltage; determine the current limiting unit resistance target value and the rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information; based on the current limiting unit resistance target value and the rated power target value, select the target current limiting unit to control the power battery for pre-charging.

[0066] In this embodiment, for the convenience of description, the following description is made by taking the identification of the power battery control module as the execution subject.

[0067] Since the existing technology often relies on experience when selecting the current limiting unit and lacks accurate calculation methods, the selection of the current limiting unit is not accurate enough. Due to the lack of a comprehensive evaluation of the performance of the current limiting unit under actual working conditions, including its instantaneous power carrying capacity, pulse tolerance and thermal stability under different ambient temperatures, it is impossible to ensure that the current limiting unit can work safely and effectively under all circumstances. In addition, the existing technology fails to fully consider the thermal capacity and temperature rise of the current limiting unit, which will cause the current limiting unit to overheat or even be damaged under continuous pulses or extreme environmental conditions, thereby affecting the reliability of the entire power battery system.

[0068] The present application provides a solution, which detects the pre-charging circuit voltage and determines the capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information according to the pre-charging circuit voltage; determines the current limiting unit resistance target value and the rated power target value according to the pre-charging circuit voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information; based on the current limiting unit resistance target value and the rated power target value, selects a target current limiting unit to control the power battery for pre-charging.

[0069] It can be seen from the above embodiments that the present application detects the pre-charging circuit voltage of the power battery system, and combines the capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information to calculate the target value of the current limiting unit resistance and the target value of the rated power, and selects the target current limiting unit, thereby ensuring the safety of the current during the pre-charging process, avoiding the impact of high-voltage electrical components by instantaneous large currents, optimizing the energy conversion and storage process, and reducing energy loss, thereby ensuring the safe operation and long-term stability of the power battery.

[0070] Based on this, the present application embodiment provides a method for selecting a current limiting unit, referring to Figure 1 , Figure 1 A schematic diagram of the flow chart of the first embodiment of the method for selecting a current limiting unit of the present application.

[0071] In this embodiment, the current limiting unit selection method includes steps S10 to S30:

[0072] Step S10, detecting the pre-charging loop voltage, and determining the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information according to the pre-charging loop voltage;

[0073] It should be noted that the high-voltage pre-charging circuit of the power battery can be simplified to an RC equivalent circuit model, such as Figure 2 As shown, Figure 2 This is an RC equivalent circuit model diagram of the pre-charging circuit of the current limiting unit selection method of the present application. The pre-charging circuit includes a power battery 10, a main positive relay K1, a main negative relay K2, a pre-charging relay K3, a current limiting unit R, a capacitor unit 20 and a load unit 30. The positive electrode of the power battery 10 is connected to the first end of the main positive relay K1 and the first end of the pre-charging relay K3, the second end of the pre-charging relay K3 is connected to the first end of the current limiting unit R, the second end of the main positive relay K1 is connected to the second end of the current limiting unit R, the first end of the capacitor unit 20 and the first end of the load unit 30, the second end of the capacitor unit 20 and the second end of the load unit 30 are both connected to the first end of the main negative relay K2, and the second end of the main negative relay K2 is connected to the negative electrode of the power battery 10.

[0074] It can be understood that the power battery system is closely connected to the motor controller. The motor controller is equipped with a bus capacitor. Based on the pre-charging circuit, the bus capacitor is pre-charged using a current limiting unit, so as to ensure that when the main circuit is connected, the pre-charging circuit current is controlled within a safe range to ensure the normal operation of the power battery system. The power battery 10 is a power battery, the capacitor unit 20 is a bus capacitor of the motor controller, the main positive relay K1, the main negative relay K2 and the pre-charging relay K3 are automatic switches of the pre-charging circuit, and the load unit 20 is a motor. When the power battery circuit enters the pre-charging process, the main negative relay K2 and the pre-charging relay K3 are closed, and the main positive relay K1 is disconnected. At this time, the power battery 10, the main negative relay K2, the pre-charging relay K3, the current limiting unit R and the capacitor unit 20 constitute a pre-charging circuit. The capacitor unit 20 is pre-charged using the current limiting function of the current limiting unit, and the capacitor unit terminal voltage U C Gradually increase, when the capacitor unit terminal voltage U C and the power battery system terminal voltage U B When the two are close, it is usually necessary to ensure that U C ≥90%U B , for example, U C =98%U B At this time, the main positive relay K1 and the main negative relay K2 are closed, the pre-charge relay K3 is disconnected, and the high-voltage pre-charge process is completed. Figure 3 As shown, Figure 3 This is a curve diagram of voltage and current changes during the pre-charging process in the first embodiment of the current limiting unit selection method of the present application.

[0075] For ease of understanding, the following description is given by taking the determination of capacitor unit characteristic information, pre-charge characteristic information and pulse characteristic information as an example, wherein the information acquisition device is an information acquisition module and the storage device is a memory.

[0076] The information acquisition module obtains the pre-charging circuit voltage and determines the capacitor unit terminal voltage U according to the pre-charging circuit voltage C , capacitor unit initial voltage U0, capacitor unit capacitance C, power battery system terminal voltage U B , Pre-charge relay rated current I k , Pre-charge circuit current I t , pre-charge time t, pulse frequency f, pulse interval time Δt and resistance operating condition information, determine the capacitor unit characteristic information based on the capacitor unit terminal voltage, the capacitor unit initial voltage and the capacitor unit capacitance value, determine the pre-charge characteristic information based on the power battery system terminal voltage, the pre-charge relay rated current, the pre-charge loop current, the resistance operating condition information and the pre-charge time, determine the pulse characteristic information based on the pulse frequency and the pulse interval time, and perform subsequent processing based on the capacitor unit characteristic information, the pre-charge characteristic information and the pulse characteristic information.

[0077] In a feasible implementation, step S10 may include steps A11 to A13:

[0078] Step A11, determining the capacitor unit terminal voltage, the capacitor unit initial voltage, the capacitor unit capacitance value, the power battery system terminal voltage, the pre-charging relay rated current, the pre-charging loop current, the resistance working condition information, the pre-charging time, the pulse frequency, and the pulse interval time according to the pre-charging loop voltage;

[0079] It should be noted that the terminal voltage of the capacitor unit is the voltage difference across the capacitor, which determines the starting point of capacitor charging. The initial voltage of the capacitor unit is the voltage level of the capacitor unit when the power battery system starts pre-charging. The capacitance value of the capacitor unit is the bus capacitance value of the motor controller, which indicates the ability to store charge. The terminal voltage of the power battery system is the voltage output by the battery, which directly affects the voltage level of the pre-charging process. The pre-charging circuit current is the current flowing through the pre-charging circuit. The resistor operating condition information reflects the thermal stability, energy dissipation capacity and power carrying capacity of the resistor under different operating conditions. The pre-charging time is the time required for the capacitor unit to reach the preset voltage level, thereby determining the duration of the pre-charging process. The pulse frequency f is the number of consecutive pulses, that is, the number of consecutive pre-chargings. The pulse interval time Δt includes the pre-charging small gap time Δt1 and the pre-charging large gap time Δt2. The pre-charging small gap time refers to the time interval between two consecutive pulses, that is, the interval between the previous pre-charging and the next pre-charging, such as Δt1=2s. The pre-charging large gap time refers to the gap time after f consecutive pre-chargings, such as Δt2=15s. Figure 4 As shown, Figure 4 This is a schematic diagram of pulse characteristic information in the first embodiment of the current limiting unit selection method of the present application.

[0080] Step A12, determining characteristic information of the capacitor unit based on the voltage at the capacitor unit terminal, the initial voltage of the capacitor unit, and the capacitance value of the capacitor unit;

[0081] It should be noted that the capacitor unit characteristic information reflects the state characteristics of the capacitor unit during the pre-charging process, including the capacitor unit terminal voltage, the capacitor unit initial voltage and the capacitor unit capacitance value.

[0082] Step A13, determining pre-charging characteristic information based on the power battery system terminal voltage, the pre-charging relay rated current, the pre-charging loop current, the resistance operating condition information, and the pre-charging time;

[0083] It should be noted that the pre-charging characteristic information reflects the characteristics of the operating state of the pre-charging process, including the power battery system terminal voltage, the pre-charging relay rated current, the pre-charging loop current, the resistance operating condition information and the pre-charging time.

[0084] Step A14, determining pulse characteristic information based on the pulse frequency and pulse interval time.

[0085] It should be noted that the pulse characteristic information reflects the characteristics of the pulse state during the pre-charging process, including the pulse frequency and the pulse interval time.

[0086] Step S20, determining a current limiting unit resistance target value and a rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information, and the pulse characteristic information;

[0087] It should be noted that the target value of the current limiting unit resistance is the target value of the current limiting unit resistance calculated during the pre-charging process, reflecting the characteristics of the target resistance value selected to meet the charging requirements, including but not limited to the starting safety resistance value, current balance resistance value, pulse energy resistance value, power overload resistance value and thermal stability resistance value; the rated power target value is the rated power target value of the current limiting unit calculated during the pre-charging process, reflecting the characteristics of the rated power target value selected to meet the charging requirements, including but not limited to the rated power characteristic value.

[0088] It is understandable that during the pre-charging process, the capacitor unit needs to be charged to a certain voltage level within a specific time. On the one hand, the resistance value of the current limiting unit can directly affect the size of the pre-charging loop current, thereby affecting the charging rate of the capacitor unit and directly determining the size of the pre-charging time. Therefore, the target value of the resistance of the current limiting unit reflects the characteristics of the efficiency of the pre-charging to ensure that the pre-charging process is both fast and safe. On the other hand, the size of the pre-charging loop current also affects the working safety of the pre-charging relay. Therefore, the target value of the resistance of the current limiting unit also reflects the characteristics of the pulse current bearing capacity to prevent damage to the battery system. During the pre-charging process, the current limiting unit needs to withstand the pulse energy. If the heat cannot be effectively dissipated, it may cause the current limiting unit to overheat, affect its performance or even damage. The resistance value of the current limiting unit will affect the energy dissipation capacity and power carrying capacity. Therefore, the target value of the resistance of the current limiting unit also reflects the characteristics of the pulse energy dissipation, power carrying capacity and thermal stability of the resistor, ensuring that the temperature of the resistor is kept within a safe range when working for a long time or continuous pulses occur, and will not be burned or fail due to heat problems, ensuring that the current limiting unit can work safely and stably during the pre-charging process.

[0089] In addition, it should be noted that in practical applications, it is necessary to ensure that the pre-charging time is as short as possible and the pre-charging circuit pulse energy is as small as possible. The larger the resistance of the current limiting unit, the longer the pre-charging time, the smaller the pre-charging circuit pulse energy, the smaller the resistance of the current limiting unit, the shorter the pre-charging time, and the larger the pre-charging circuit pulse energy. It can be seen that the selection of the current limiting unit should not only consider the resistance value, but also determine the rated power. Therefore, it is necessary to comprehensively consider the starting safety resistance value, current balance resistance value, pulse energy resistance value, power overload resistance value, thermal stability resistance value and rated power characteristic value, determine the current limiting unit resistance target value and rated power target value, and thus select a suitable current limiting unit to ensure that the pre-charging circuit current is controlled within a safe range during the pre-charging stage, thereby protecting the battery system from current shocks, reducing energy loss, and improving overall energy efficiency to maintain system stability and extend service life.

[0090] For ease of understanding, an explanation is given by taking determining a target value of resistance of a current limiting unit as an example, wherein the information acquisition device is an information acquisition module, the storage device is a memory, and the processing device is a processing module.

[0091] After the information acquisition module obtains the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information, the information acquisition module determines the target value of the current limiting unit resistance according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information, and obtains the current limiting unit characteristic information and the current limiting unit temperature characteristic information. The current limiting unit characteristic information includes but is not limited to the instantaneous terminal voltage of the current limiting unit, the peak energy of the current limiting unit, the mass of the current limiting unit, the specific heat capacity of the current limiting unit material, the power safety factor and the power overload factor. The current limiting unit temperature characteristic information includes but is not limited to the current limiting unit target temperature, the current limiting unit initial temperature and the current limiting unit operating temperature limit. A current limiting unit loop model is constructed based on the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information, the pulse characteristic information, the current limiting unit characteristic information and the current limiting unit temperature characteristic information. The current limiting unit loop model includes a first loop model, a second loop model, a third loop model, a fourth loop model and a fifth loop model. Subsequent processing is performed based on the current limiting unit loop model.

[0092] Step S30: Based on the target value of the resistance of the current limiting unit and the target value of the rated power, a target current limiting unit is selected to control the power battery to perform pre-charging.

[0093] It should be noted that the target current limiting unit reflects the characteristics of the current limiting unit selected to meet the expected requirements during the pre-charging process.

[0094] It can be understood that based on the calculated resistance target value and rated power target value, the current limiting unit that is closest and meets the technical specifications is selected to ensure precise control of the current during the pre-charging process, avoid damage to the battery system caused by current shock, and optimize the pre-charging parameter settings, such as pre-charging time, pulse frequency, etc., to achieve more efficient energy conversion and storage. When an abnormal situation is detected, such as abnormal current or excessive temperature, protective measures are immediately initiated, such as power off or starting the cooling system, to protect system safety.

[0095] In one embodiment, in order to facilitate the selection of a target current limiting unit to control the pre-charging of the power battery based on the target value of the current limiting unit resistance and the target value of the rated power, a corresponding execution device, such as a control module, an execution module, etc., can be pre-set to select the corresponding target current limiting unit to control the pre-charging of the power battery.

[0096] For ease of understanding, the following description is given by taking the acquisition of the target value of the resistance of the current limiting unit and the target value of the rated power as an example, wherein the information acquisition device is the information acquisition module, the storage device is the memory, and the execution device is the execution module.

[0097] After the information acquisition module obtains the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information, the information acquisition module determines the current limiting unit resistance target value and the rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information, obtains the current limiting unit characteristic information and the current limiting unit temperature characteristic information, and constructs a current limiting unit loop model based on the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information, the pulse characteristic information, the current limiting unit characteristic information and the current limiting unit temperature characteristic information, calculates the starting safety resistance value, the current balance resistance value, the pulse energy resistance value, the rated power characteristic value, the power overload resistance value and the thermal stability resistance value based on the current limiting unit loop model, and determines the current limiting unit resistance target value and the rated power target value based on the starting safety resistance value, the current balance resistance value, the pulse energy resistance value, the rated power characteristic value, the power overload resistance value and the thermal stability resistance value, thereby selecting a suitable target current limiting unit to control the power battery for pre-charging.

[0098] The current limiting unit selection method proposed in this embodiment detects the pre-charging circuit voltage, and determines the capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information according to the pre-charging circuit voltage; determines the current limiting unit resistance target value and the rated power target value according to the pre-charging circuit voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information; based on the current limiting unit resistance target value and the rated power target value, selects a target current limiting unit to control the power battery for pre-charging, thereby solving the technical problem of generating instantaneous large current during the high-voltage power-on process of the whole vehicle, impacting the high-voltage electrical components and causing failures. Compared with the prior art, the present application detects the pre-charging circuit voltage of the power battery system, and combines the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information to calculate the current limiting unit resistance target value and the rated power target value, and selects the target current limiting unit, thereby ensuring the safety of the current during the pre-charging process, avoiding the high-voltage electrical components from being impacted by instantaneous large currents, optimizing the energy conversion and storage process, reducing energy loss, and thus ensuring the safe operation and long-term stability of the power battery.

[0099] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction and will not be repeated later.

[0100] In this embodiment, refer to Figure 5 , Figure 5 The flowchart of the second embodiment of the method for selecting a current limiting unit of the present application is provided, wherein step S20 specifically includes steps S201 to S203:

[0101] Step S201, determining a startup safety resistance value and a current balance resistance value based on a pre-charge loop voltage, pre-charge characteristic information, and capacitor unit characteristic information;

[0102] It should be noted that the starting safety resistance value reflects the characteristics of the current limiting unit calculated when the capacitor unit is pre-charged during the pre-charging process, and the current balancing resistance value reflects the characteristics of the current limiting unit calculated when the capacitor unit is short-circuited at the moment the pre-charging relay is just closed during the pre-charging process.

[0103] For ease of understanding, obtaining a startup safety resistance value and a current balance resistance value is taken as an example for explanation, wherein the information acquisition device is an information acquisition module, the storage device is a memory, and the processing device is a processing module.

[0104] The information acquisition module obtains the pre-charging time t and the capacitor unit terminal voltage. The capacitor unit terminal voltage is the capacitor unit terminal voltage U corresponding to the time t during the pre-charging process. C, obtain the initial voltage of the capacitor unit. The initial voltage of the capacitor unit is the voltage level of the capacitor unit when the power battery system starts pre-charging, that is, the initial voltage of the capacitor unit U0, obtain the capacitance value of the capacitor unit. The capacitance value of the capacitor unit is the bus capacitance value C of the motor controller, and obtain the terminal voltage of the power battery system. The terminal voltage of the power battery system is the terminal voltage of the power battery system U B , and stores the pre-charge time, capacitor unit terminal voltage, capacitor unit initial voltage, capacitor unit capacitance value and power battery system terminal voltage in the memory, the processing module builds a first loop model based on the pre-charge loop voltage, pre-charge feature information and capacitor unit feature information, and calculates the startup safety resistance value R1 based on the resistance working condition information in the pre-charge feature information and the power battery system terminal voltage and the capacitor unit terminal voltage, capacitor unit initial voltage, capacitor unit capacitance value and the first loop model in the capacitor unit feature information.

[0105] At this time, the voltage at the capacitor unit terminal satisfies the following relationship:

[0106]

[0107] Among them, U C is the terminal voltage of the capacitor unit, U0 is the initial voltage of the capacitor unit, U B is the terminal voltage of the power battery system, e is a natural constant, which is the base of the exponential function, e is a natural constant, which is the base of the exponential function, R1 is the starting safety resistance value, and C is the capacitance value of the capacitor unit.

[0108] Therefore, the startup safety resistance value R1 can be obtained:

[0109]

[0110] Wherein, ln is a logarithmic function with the natural constant e as the base, R1 is the startup safety resistance value, and C is the capacitance value of the capacitor unit.

[0111] According to the preset pre-charge time threshold t limit , it can be determined that the first loop model formula satisfied by the startup safety resistance value of the current limiting unit is:

[0112]

[0113] For example, according to the electrochemical principle, U0=0, usually, it is required that U C ≥90%U B , commonly used, U C =98%U B , substituting into the formula, we can get:

[0114]

[0115] Usually, the pre-charge time t is required to be ≤ 500ms. For example, if the pre-charge time t is 200ms, the first loop model formula that the startup safety resistance value of the current limiting unit satisfies can be determined as follows:

[0116] 4.R1.C.≤200

[0117] During the pre-charging process, according to the "AC passing and DC blocking" characteristics of the capacitor unit, the main negative relay K2 and the pre-charging relay K3 are just closed. At this moment, the capacitor unit is equivalent to a short circuit. According to the electrochemical principle, the second loop model formula is constructed.

[0118] The pre-charging circuit current I(t) during the pre-charging process in the second circuit model formula is:

[0119]

[0120] Where I(t) is the pre-charging circuit current during the pre-charging process, I k is the rated current of the pre-charge relay, and R2 is the current balancing resistance value.

[0121] Therefore, it can be obtained that the current balancing resistance value R2 is:

[0122]

[0123] In a feasible implementation, step S201 may include steps B21 to B24:

[0124] Step B21, constructing a first loop model based on the pre-charge loop voltage, the pre-charge characteristic information, and the capacitor unit characteristic information;

[0125] It should be noted that by constructing the first-loop model, the starting safety resistance value can be calculated to prevent the generation of instantaneous large current during pre-charging, ensure that the circuit components will not be damaged by current shock, and ensure that the pre-charging loop current is controlled within a safe and stable range to avoid excessive or small current affecting the pre-charging efficiency and safety.

[0126] Step B22, constructing a second loop model based on the pre-charge loop voltage and the pre-charge characteristic information;

[0127] It should be noted that, by constructing the second loop model, combined with the pre-charging characteristic information and the capacitor unit characteristic information, the current balancing resistance value can be determined to maintain the current balance during the pre-charging process.

[0128] Step B23, calculating the startup safety resistance value based on the resistance operating condition information and the power battery system terminal voltage in the pre-charge characteristic information, the capacitor unit terminal voltage, the capacitor unit initial voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, and the first loop model;

[0129] It should be noted that the startup safety resistance value is proportional to the pre-charge time. The larger the startup safety resistance value, the longer the pre-charge time, and the pre-charge time needs to be less than the preset time threshold to ensure the pre-charge efficiency. At the same time, the startup safety resistance value can ensure that the loop current is controlled within a safe range at the beginning of pre-charge to prevent current shock from damaging the circuit.

[0130] Step B24, calculating the current balancing resistance value based on the resistance operating condition information in the pre-charging characteristic information, the power battery system terminal voltage, the pre-charging relay rated current and the second loop model.

[0131] It should be noted that by calculating the starting safety resistance value and the current balance resistance value, the current can be effectively limited at the beginning of pre-charging, reducing the impact on circuit components and reducing the risk of damage. At the same time, it ensures the uniform distribution of current during pre-charging, avoids local overheating, improves charging efficiency, and also helps to extend the service life of power batteries and circuit components.

[0132] Step S202, determining a pulse energy resistance value, a rated power characteristic value, a power overload resistance value, and a thermal stability resistance value based on the pre-charge loop voltage, the pre-charge characteristic information, and the pulse characteristic information;

[0133] It should be noted that the pulse energy resistance value reflects the characteristic of the current limiting unit to safely absorb pulse energy during the pulse process, the rated power characteristic value reflects the characteristic of the current limiting unit to meet the maximum power for safe operation, the power overload resistance value reflects the characteristic of the current limiting unit to resist instantaneous pulse energy, and the thermal stability resistance value reflects the characteristic of the current limiting unit to meet the expected temperature rise when absorbing pulse energy.

[0134] It can be understood that the peak power of the current limiting unit is determined based on the terminal voltage and resistance operating condition information of the power battery system in the pre-charging characteristic information. The peak power of the current limiting unit reflects the maximum value of the pre-charging power during the pre-charging process. If the current limiting unit is subjected to high power in a short period of time, it will quickly generate a large amount of heat. The level of peak power determines the thermal stability of the current limiting unit, that is, the ability to operate safely without exceeding the operating temperature limit. The peak power of the current limiting unit can ensure that the current limiting unit will not be damaged due to excessive power during the pre-charging process, and can avoid safety risks to the entire power battery system. The rated power characteristic value of the current limiting unit is determined based on the power safety factor, power overload factor and peak power of the current limiting unit in the characteristic information of the current limiting unit. The rated power characteristic value of the current limiting unit reflects the characteristics of the continuous power level that can be safely carried during the pre-charging process, and also reflects the thermal stability and reliability of the current limiting unit during long-term operation, ensuring that under the expected workload, the current limiting unit will not reduce performance or be damaged due to overheating, thereby ensuring the safe and stable operation of the entire system.

[0135] In addition, it should be noted that the power overload state is judged based on the power safety factor and the power overload factor in the rated power characteristic value and the characteristic information of the current limiting unit, and the judgment result is obtained. The power overload resistance value is selected and determined based on the judgment result. The judgment result reflects the characteristics of the target current limiting unit selected under different working conditions. The power overload resistance value is selected and determined based on the judgment result, so as to select the appropriate current limiting unit type and specification. In the case of continuous pulse charging, the current limiting unit needs to withstand periodic power shocks. The calculated power overload resistance value reflects the current limiting unit's ability to withstand pulse currents, thereby ensuring that the selected current limiting unit will not be damaged due to excessive instantaneous power during the pulse charging process.

[0136] For ease of understanding, the pulse energy resistance value, rated power characteristic value, power overload resistance value and thermal stability resistance value are taken as an example for explanation, wherein the information acquisition device is the information acquisition module, the storage device is the memory, and the processing device is the processing module.

[0137] The information acquisition module obtains the characteristic information of the current limiting unit and the temperature characteristic information of the current limiting unit, obtains the pulse frequency f, the pulse frequency is the number of continuous pulses, obtains the pulse interval time Δt, the pulse interval time Δt includes the pre-charge small gap time Δt1 and the pre-charge large gap time Δt2, the pre-charge small gap time refers to the time interval between two consecutive pulses, that is, the interval between the previous pre-charge and the next pre-charge, such as Δt1 = 2s, the pre-charge large gap time refers to the gap time after continuous pre-charge f times, and the current limiting unit characteristic information, the current limiting unit temperature characteristic information, the pulse frequency ... The pulse interval time is stored in the memory, and the processing module constructs a third loop model, a fourth loop model and a fifth loop model based on the pre-charge characteristic information, the pulse characteristic information, the current limiting unit characteristic information and the current limiting unit temperature characteristic information, and calculates the pulse energy resistance value based on the power battery system terminal voltage, the pre-charge loop current, the pre-charge time in the pre-charge characteristic information, the capacitor unit terminal voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, the pulse frequency in the pulse characteristic information, the pulse interval time, the current limiting unit instantaneous terminal voltage, the current limiting unit peak energy in the current limiting unit characteristic information and the third loop model.

[0138] The formula for determining the energy supply of the power battery based on the third circuit model is as follows:

[0139]

[0140] The energy storage formula of capacitor unit is:

[0141]

[0142] Therefore, the pulse energy formula of the pre-charge circuit is: W R =f·(W t-W C )

[0143] Among them, U C is the voltage across the capacitor unit, U B is the terminal voltage of the power battery system, I(t) is the pre-charging circuit current during the pre-charging process, t is the pre-charging time, C is the capacitance value of the capacitor unit, and f is the pulse frequency.

[0144] It can be understood that if it is a single pulse, f=1; if it is a continuous pulse, when the pre-charge small gap time Δt1 is less than the preset interval time, the pre-charge loop pulse energy can generally be calculated by linear accumulation.

[0145] It should be noted that the peak energy of the current limiting unit refers to the maximum energy that the current limiting unit can withstand during the pre-charging process, which reflects the energy dissipation and carrying capacity of the current limiting unit and affects whether the current limiting unit can safely absorb the pulse energy of the pre-charging circuit. Therefore, calculating the pulse energy of the pre-charging circuit helps to determine the maximum energy that the current limiting unit needs to withstand, so as to select the appropriate resistor type and specification to prevent resistor damage or system failure due to overheating.

[0146] The formula for determining the peak energy of the current limiting unit based on the third loop model is:

[0147] Q(t)≥W R

[0148] Wherein, Q(t) is the peak energy of the current limiting unit.

[0149] According to the electrochemical principle, the peak energy of the current limiting unit satisfies the following formula:

[0150]

[0151] Among them, U R is the instantaneous terminal voltage of the current limiting unit, U R,max It is the maximum value of the instantaneous terminal voltage of the current limiting unit during the pre-charging process.

[0152] It can be understood that when the main negative relay K2 and the pre-charge relay K3 are just closed, the capacitor unit is equivalent to a short circuit, and the voltage across the current limiting unit is the largest. Therefore, the maximum instantaneous terminal voltage of the current limiting unit is equal to the terminal voltage of the power battery, that is, U R,max =U B ,but

[0153]

[0154] Therefore, it can be obtained that the pulse energy resistance value R3 is:

[0155]

[0156] Among them, U B is the terminal voltage of the power battery system, U C is the terminal voltage of the capacitor unit, C is the capacitance value of the capacitor unit, I(t) is the pre-charge loop current during the pre-charge process, t is the pre-charge time, and f is the pulse frequency.

[0157] It can be seen from the pulse energy resistance value calculation formula that based on the power battery system terminal voltage, pre-charging loop current, pre-charging time in the pre-charging characteristic information, the capacitor unit terminal voltage, capacitor unit capacitance in the capacitor unit characteristic information, the pulse frequency and pulse interval time in the pulse characteristic information, the appropriate resistor type and specification are selected to determine the pulse energy resistance value of the current limiting unit.

[0158] The processing module calculates the power overload resistance value based on the resistance operating condition information in the pre-charge characteristic information, the power battery system terminal voltage and the power safety factor, the power overload factor and the fourth loop model in the current limiting unit characteristic information.

[0159] Determine the peak power of the current limiting unit based on the fourth circuit model and the resistor operating condition information:

[0160]

[0161] Among them, P R is the peak power of the current limiting unit, U R,max is the maximum instantaneous terminal voltage of the current limiting unit during the pre-charging process, and R4 is the power overload resistance value.

[0162] It can be understood that when the main negative relay K2 and the pre-charge relay K3 are just closed, the capacitor unit is equivalent to a short circuit, and the voltage across the current limiting unit is the largest. Therefore, the maximum instantaneous terminal voltage of the current limiting unit is equal to the terminal voltage of the power battery, that is, U R,max =U B , then the peak power of the current limiting unit is:

[0163]

[0164] Determine the rated power characteristic value based on the power safety factor, power overload factor, and peak power of the current limiting unit in the characteristic information of the current limiting unit:

[0165]

[0166] Among them, P reted is the rated power characteristic value, γ is the power safety factor, ε is the power overload factor, and R4 is the power overload resistance value.

[0167] It can be understood that the rated power characteristic value is the continuous working power at which the current limiting unit can operate safely; the power overload factor refers to the ability of the current limiting unit to withstand power exceeding its rated power in a short period of time, which is defined in the manufacturer's product specification definition book; the power safety factor is determined by the safety level and usage requirements, and is flexibly adjusted according to actual conditions, and this patent does not make specific limitations.

[0168] In addition, it can be understood that the rated power target value of the current limiting unit should be greater than or equal to the rated power characteristic value.

[0169] Therefore, the power overload resistor value R4 is calculated as:

[0170]

[0171] It can be seen from the power overload resistance value calculation formula that based on the rated power characteristic value and the power safety factor and power overload factor in the characteristic information of the current limiting unit, the appropriate resistor type and specification are selected to determine the rated power target value and power overload resistance value of the current limiting unit.

[0172] It should be noted that the power overload factor and the continuous overload time T over Satisfying the empirical formula, the power overload factor decreases with the increase of continuous overload time, which can be expressed by the exponential decay model as follows:

[0173]

[0174] Among them, ε is the power overload factor, b is the decay rate, which indicates the rate at which the power overload factor decays with time, and is a key parameter that affects how fast the curve drops. a is the initial overload capacity, which indicates the initial power overload factor of the resistor when time is zero, that is, the peak overload capacity before time decay. c is the steady-state overload capacity, which indicates the stable value to which the power overload factor of the resistor tends to when time tends to infinity, and is usually related to the long-term thermal stability of the resistor. The power overload state is judged based on the power safety factor and the power overload factor in the rated power characteristic value and the characteristic information of the current limiting unit, and the judgment result is obtained. It is required that the continuous overload time is greater than or equal to the pulse duration so that the pulse process can be flexibly adjusted, thereby reasonably selecting the power overload resistance value.

[0175] The processing module calculates the thermal stability resistance value based on the power battery system terminal voltage in the pre-charging characteristic information, the pre-charging time and the instantaneous terminal voltage of the current limiting unit in the current limiting unit characteristic information, the current limiting unit mass, the specific heat capacity of the current limiting unit material, the current limiting unit target temperature in the current limiting unit temperature characteristic information, the current limiting unit initial temperature, the current limiting unit operating temperature limit and the fifth loop model.

[0176] According to electrochemical principles, during the pre-charging process, the thermal stability resistor generates heat due to the absorption of pulse energy, causing the resistor temperature to rise. However, it is necessary to ensure that the temperature of the resistor remains within a safe range during long-term operation or continuous pulses, and will not be burned or fail due to thermal problems, thereby ensuring that the current limiting unit can work safely and stably during the pre-charging process. The temperature formula for determining the thermal stability resistor value at the end of the pre-charging process based on the fifth loop model is:

[0177]

[0178] Among them, U R is the instantaneous terminal voltage of the current limiting unit, t is the pre-charge time, m R is the quality of thermal stability resistance value, c p The specific heat capacity of the thermal stability resistor material, that is, the energy required to increase or decrease the unit mass of the material by 1 degree Celsius, T R is the temperature of the thermal stability resistance value at the end of the pre-charging process, T0 is the initial temperature of the thermal stability resistance value at the beginning of the pre-charging process, T MAX is the operating temperature limit of the thermal stability resistance value, and R5 is the thermal stability resistance value.

[0179] It can be understood that the maximum instantaneous terminal voltage of the current limiting unit is equal to the terminal voltage of the power battery, that is, U R,max =U B .

[0180] Therefore, the thermal stability resistance value R5 is calculated as:

[0181]

[0182] It can be seen from the thermal stability resistance value calculation formula that the thermal stability resistance value is calculated based on the power battery system terminal voltage in the pre-charging characteristic information, the instantaneous terminal voltage of the current limiting unit in the current limiting unit characteristic information, the current limiting unit mass, the specific heat capacity of the current limiting unit material, the current limiting unit target temperature in the current limiting unit temperature characteristic information, the current limiting unit initial temperature, and the current limiting unit operating temperature limit, so as to select the appropriate resistor type and specification and determine the thermal stability resistance value of the current limiting unit.

[0183] In a feasible implementation, step S202 may include steps C21 to C27:

[0184] Step C21, obtaining the instantaneous terminal voltage of the current limiting unit, the peak energy of the current limiting unit, the mass of the current limiting unit, the specific heat capacity of the current limiting unit material, the power safety factor, the power overload factor, the target temperature of the current limiting unit, the initial temperature of the current limiting unit, and the operating temperature limit of the current limiting unit;

[0185] It should be noted that the instantaneous terminal voltage of the current limiting unit, the peak energy of the current limiting unit, the mass of the current limiting unit, the specific heat capacity of the current limiting unit material, the power safety factor, the power overload factor, the target temperature of the current limiting unit, the initial temperature of the current limiting unit and the operating temperature limit of the current limiting unit can be obtained by the information collection device.

[0186] Step C22, determining characteristic information of the current limiting unit based on the instantaneous terminal voltage of the current limiting unit, the peak energy of the current limiting unit, the mass of the current limiting unit, the specific heat capacity of the material of the current limiting unit, the power safety factor, and the power overload factor;

[0187] It should be noted that the current limiting unit characteristic information reflects the characteristics of the current limiting unit state during the pre-charging process.

[0188] Step C23, determining the temperature characteristic information of the current limiting unit based on the target temperature of the current limiting unit, the initial temperature of the current limiting unit and the operating temperature limit of the current limiting unit;

[0189] It should be noted that the current limiting unit temperature characteristic information reflects the characteristics of the current limiting unit temperature during the pre-charging process.

[0190] Step C24, constructing a third loop model, a fourth loop model and a fifth loop model based on the pre-charge characteristic information, the pulse characteristic information, the current limiting unit characteristic information and the current limiting unit temperature characteristic information;

[0191] It should be noted that, through the constructed third loop model, the pulse energy resistance value can be calculated, and the thermal stability and safety of the resistor can be evaluated under the worst conditions, such as when the battery voltage peak and the maximum number of pulses are reached, to prevent damage to the resistor or system failure due to overheating. In order to ensure that the current limiting unit can still work normally under overload conditions and is not damaged due to overheating, the power overload resistance value can be calculated through the constructed fourth loop model, which ensures the thermal stability of the current limiting unit under power overload conditions and avoids system failures due to overheating. For the current limiting unit actually used in the battery management system, it will absorb a large amount of energy in a short period of time during the pre-charging process, causing the temperature to rise rapidly. To ensure that the current limiting unit does not fail after 2-3 consecutive power-on pre-charging, the instantaneous thermal response and thermal conductivity characteristics of the resistor need to be considered. In order to ensure that the current limiting unit can remain stable under continuous operation or high temperature environment, the thermal stability resistance value can be calculated through the constructed fifth loop model, thereby maintaining the performance of the current limiting unit under continuous operation or high temperature environment, reducing the risk of failure due to thermal problems.

[0192] Step C25, calculating the pulse energy resistance value based on the power battery system terminal voltage, pre-charging loop current, pre-charging time in the pre-charging characteristic information, the capacitor unit terminal voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, the pulse frequency, the pulse interval time in the pulse characteristic information, the current limiting unit instantaneous terminal voltage, the current limiting unit peak energy in the current limiting unit characteristic information, and the third loop model;

[0193] It should be noted that calculating the pulse energy resistor value helps determine the maximum energy that the current limiting unit needs to withstand, so as to select the appropriate resistor type and specification to ensure that the resistor can safely dissipate the energy during the pre-charging process.

[0194] Step C26, calculating the rated power characteristic value and the power overload resistance value based on the resistance operating condition information in the pre-charge characteristic information, the power battery system terminal voltage and the power safety factor and the power overload factor in the current limiting unit characteristic information and the fourth loop model;

[0195] It should be noted that calculating the power overload resistance value ensures the thermal stability of the current limiting unit under overload conditions and avoids system failure due to overheating.

[0196] Step C27, calculate the thermal stability resistance value based on the power battery system terminal voltage in the pre-charging characteristic information, the pre-charging time and the instantaneous terminal voltage of the current limiting unit in the current limiting unit characteristic information, the current limiting unit mass, the specific heat capacity of the current limiting unit material, the current limiting unit target temperature in the current limiting unit temperature characteristic information, the current limiting unit initial temperature, the current limiting unit operating temperature limit and the fifth loop model.

[0197] It should be noted that the thermal stability resistance value is calculated to maintain the performance of the current limiting unit in a continuous pulse or high temperature environment, reducing the risk of failure due to thermal problems.

[0198] In another feasible implementation, step S202 may include steps D21 to D24:

[0199] Step D21, calculating energy information based on the power battery system terminal voltage, pre-charge loop current, pre-charge time in the pre-charge characteristic information, the capacitor unit terminal voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, the pulse frequency, and the pulse interval time in the pulse characteristic information, where the energy information includes the power battery supply energy and the capacitor unit storage energy;

[0200] It should be noted that the energy information reflects the characteristics of the energy generated by the pulse in the pre-charging circuit, including the energy supplied by the power battery and the energy stored in the capacitor unit.

[0201] Step D22, calculating the pre-charging circuit pulse energy based on the energy supplied by the power battery and the energy stored in the capacitor unit;

[0202] It should be noted that calculating the pulse energy resistance value of the pre-charging circuit helps determine the maximum energy that the current limiting unit needs to withstand, thereby selecting the appropriate resistor type and specification to ensure that the resistor can safely dissipate the energy during the pre-charging process.

[0203] Step D23, judging the energy absorption state based on the pre-charging loop pulse energy and the current limiting unit peak energy in the current limiting unit characteristic information, and obtaining a judgment result;

[0204] It should be noted that the judgment result reflects the characteristics of judging the energy absorption state during the pre-charging process.

[0205] Step D24, selecting and determining the pulse energy resistance value based on the judgment result.

[0206] It should be noted that the judgment result reflects the characteristics of the target current limiting unit selected under different working conditions.

[0207] Step S203, obtaining a current limiting unit resistance target value and a rated power target value based on the pre-charging loop voltage, the startup safety resistance value, the current balance resistance value, the pulse energy resistance value, the rated power characteristic value, the power overload resistance value and the thermal stability resistance value.

[0208] It should be noted that based on the pre-charging loop voltage, starting safety resistance value, current balance resistance value, pulse energy resistance value, rated power characteristic value, power overload resistance value and thermal stability resistance value, the current limiting unit resistance target value and rated power target value are determined to accurately select a suitable current limiting unit.

[0209] It is understandable that, since the pre-charging time is in the ms millisecond level during the pre-charging process, and the pre-charging time t≤200ms, it is necessary to pay attention to the tolerance limit of the instantaneous energy of the current limiting unit, that is, the peak energy of the current limiting unit. The peak energy of the current limiting unit reflects the characteristics of the thermal response of the current limiting unit, which can affect whether the current limiting unit can safely absorb the pre-charging circuit pulse energy. Based on the pre-charging circuit voltage, starting safety resistance value, current balance resistance value, pulse energy resistance value, rated power characteristic value, power overload resistance value and thermal stability resistance value, the current limiting unit resistance target value and rated power target value are determined. Since the actual working environment may change, such as temperature fluctuations Therefore, the selected target current limiting unit may need to be dynamically selected according to the calculated target value of the current limiting unit resistance to adapt to different working conditions, and a safety threshold will be set to select a target current limiting protection unit that fully meets the expected needs to ensure that the current limiting unit can work safely even under the most unfavorable conditions, avoid system failures caused by calculation errors or environmental changes, consider environmental factors such as humidity, corrosive gases, and other factors that affect the performance and life of the resistor material, select appropriate resistor materials and specifications while ensuring safety and performance, and consider cost-effectiveness to achieve the best balance between economy and reliability.

[0210] The current limiting unit selection method proposed in this embodiment determines the starting safety resistance value and the current balance resistance value based on the pre-charging loop voltage, pre-charging characteristic information and the capacitor unit characteristic information; determines the pulse energy resistance value, the rated power characteristic value, the power overload resistance value and the thermal stability resistance value based on the pre-charging loop voltage, the pre-charging characteristic information and the pulse characteristic information; determines the current limiting unit resistance target value and the rated power target value based on the pre-charging loop voltage, the starting safety resistance value, the current balance resistance value, the pulse energy resistance value, the rated power characteristic value, the power overload resistance value and the thermal stability resistance value, solves the technical problem of dynamically selecting the current limiting unit resistance target value when the pre-charging loop operating condition changes. Compared with the prior art, the present application can effectively avoid current shock and overheating problems by reasonably selecting the current limiting unit resistance target value to determine the current limiting unit, thereby improving the safety of the power battery system, adapting to different operating conditions and requirements, and improving the adaptability and flexibility of the system.

[0211] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the method for selecting the current limiting unit of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0212] This application also provides a current limiting unit selection device, please refer to Figure 6 , Figure 6 This is a schematic diagram of the module structure of the current limiting unit selection device according to an embodiment of the present application. The current limiting unit selection device includes:

[0213] An acquisition module 10 is used to detect a pre-charging loop voltage and determine capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information according to the pre-charging loop voltage;

[0214] The processing module 20 is used to determine the current limiting unit resistance target value and the rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information;

[0215] The execution module 30 is used to select a target current limiting unit to control the power battery to perform pre-charging based on the target value of the resistance of the current limiting unit and the target value of the rated power.

[0216] The current limiting unit selection device provided in the present application adopts the current limiting unit selection method in the above embodiment, which can solve the technical problem of how to accurately select the current limiting unit. Compared with the prior art, the beneficial effects of the current limiting unit selection device provided in the present application are the same as the beneficial effects of the current limiting unit selection method provided in the above embodiment, and other technical features in the current limiting unit selection device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0217] The present application provides a current limiting unit selection device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the current limiting unit selection method in the above-mentioned embodiment one.

[0218] Reference below Figure 7 , which shows a schematic diagram of the structure of a current limiting unit selection device suitable for implementing the embodiment of the present application. The current limiting unit selection device in the embodiment of the present application may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 7 The current limiting unit selection device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0219] like Figure 7As shown, the current limiting unit selection device may include a processing device 1001 (such as a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the current limiting unit selection device are also stored. The processing device 1001, ROM1002 and RAM1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems can be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 1008 including, for example, a liquid crystal display (LCD: Liquid Crystal Display), a speaker, a vibrator, etc.; a storage device 1003 including, for example, a tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the current limiting unit selection device to communicate with other devices wirelessly or wired to exchange data. Although the figure shows a current limiting unit selection device with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems can be implemented or have alternatively.

[0220] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0221] The current limiting unit selection device provided in the present application adopts the current limiting unit selection method in the above embodiment, which can solve the technical problem of how to accurately select the current limiting unit. Compared with the prior art, the beneficial effects of the current limiting unit selection device provided in the present application are the same as the beneficial effects of the current limiting unit selection method provided in the above embodiment, and the other technical features in the current limiting unit selection device are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0222] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0223] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0224] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the current limiting unit selection method in the above-mentioned embodiment.

[0225] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0226] The computer-readable storage medium may be included in the current limiting unit selection device; or may exist independently without being assembled into the current limiting unit selection device.

[0227] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the current limiting unit selection device, the current limiting unit selection device: detects the pre-charging loop voltage, and determines the capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information according to the pre-charging loop voltage; determines the current limiting unit resistance target value and the rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information; based on the current limiting unit resistance target value and the rated power target value, selects a target current limiting unit to control the power battery for pre-charging.

[0228] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0229] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0230] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0231] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned current limiting unit selection method, and can solve the technical problem of how to accurately select the current limiting unit. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the current limiting unit selection method provided in the above-mentioned embodiment, and will not be repeated here.

[0232] The above are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for selecting a current limiting unit, characterized in that: The current limiting unit selection method is applied to a pre-charging circuit, the pre-charging circuit includes a power battery, a main positive relay, a main negative relay, a pre-charging relay, a current limiting unit, a capacitor unit and a load unit, the positive electrode of the power battery is connected to the first end of the main positive relay and the first end of the pre-charging relay, the second end of the pre-charging relay is connected to the first end of the current limiting unit, the second end of the main positive relay is connected to the second end of the current limiting unit, the first end of the capacitor unit and the first end of the load unit, the second end of the capacitor unit and the second end of the load unit are both connected to the first end of the main negative relay, and the second end of the main negative relay is connected to the negative electrode of the power battery, the method includes: Detecting a pre-charging loop voltage, and determining capacitor unit characteristic information, pre-charging characteristic information, and pulse characteristic information according to the pre-charging loop voltage; Determine a current limiting unit resistance target value and a rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information, and the pulse characteristic information; Based on the target value of the resistance of the current limiting unit and the target value of the rated power, a target current limiting unit is selected to control the power battery to perform pre-charging.

2. The method according to claim 1, characterized in that The step of determining the capacitor unit characteristic information, the pre-charge characteristic information and the pulse characteristic information according to the pre-charge loop voltage comprises: Determine the capacitor unit terminal voltage, the capacitor unit initial voltage, the capacitor unit capacitance, the power battery system terminal voltage, the pre-charge relay rated current, the pre-charge loop current, the resistance working condition information, the pre-charge time, the pulse frequency, and the pulse interval time according to the pre-charge loop voltage; Determining capacitor unit characteristic information based on the capacitor unit terminal voltage, the capacitor unit initial voltage, and the capacitor unit capacitance value; Determine pre-charging characteristic information based on the power battery system terminal voltage, the pre-charging relay rated current, the pre-charging loop current, the resistance operating condition information, and the pre-charging time; Pulse characteristic information is determined based on the pulse frequency and the pulse interval time.

3. The method according to claim 1, characterized in that The step of determining the current limiting unit resistance target value and the rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information and the pulse characteristic information comprises: Determine a startup safety resistance value and a current balance resistance value based on the pre-charge loop voltage, the pre-charge characteristic information, and the capacitor unit characteristic information; Determine a pulse energy resistance value, a rated power characteristic value, a power overload resistance value, and a thermal stability resistance value based on the pre-charge loop voltage, the pre-charge characteristic information, and the pulse characteristic information; The current limiting unit resistance target value and the rated power target value are obtained based on the pre-charging loop voltage, the startup safety resistance value, the current balance resistance value, the pulse energy resistance value, the rated power characteristic value, the power overload resistance value and the thermal stability resistance value.

4. The method according to claim 3, characterized in that The step of determining the startup safety resistance value and the current balance resistance value based on the pre-charge loop voltage, the pre-charge characteristic information and the capacitor unit characteristic information comprises: Constructing a first loop model based on the pre-charging loop voltage, the pre-charging characteristic information, and the capacitor unit characteristic information; Constructing a second loop model based on the pre-charge loop voltage and the pre-charge characteristic information; Calculate the startup safety resistance value based on the resistance operating condition information and the power battery system terminal voltage in the pre-charge characteristic information, the capacitor unit terminal voltage, the capacitor unit initial voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, and the first loop model; The current balancing resistance value is calculated based on the resistance operating condition information in the pre-charging characteristic information, the power battery system terminal voltage, the pre-charging relay rated current and the second loop model.

5. The method according to claim 3, characterized in that The step of determining the pulse energy resistance value, the rated power characteristic value, the power overload resistance value and the thermal stability resistance value based on the pre-charge loop voltage, the pre-charge characteristic information and the pulse characteristic information comprises: Obtain the instantaneous terminal voltage of the current limiting unit, the peak energy of the current limiting unit, the mass of the current limiting unit, the specific heat capacity of the current limiting unit material, the power safety factor, the power overload factor, the target temperature of the current limiting unit, the initial temperature of the current limiting unit, and the operating temperature limit of the current limiting unit; Determining the current limiting unit characteristic information based on the instantaneous terminal voltage of the current limiting unit, the peak energy of the current limiting unit, the mass of the current limiting unit, the specific heat capacity of the current limiting unit material, the power safety factor, and the power overload factor; Determine the current limiting unit temperature characteristic information based on the current limiting unit target temperature, the current limiting unit initial temperature and the current limiting unit operating temperature limit; Constructing a third loop model, a fourth loop model and a fifth loop model based on the pre-charge characteristic information, the pulse characteristic information, the current limiting unit characteristic information and the current limiting unit temperature characteristic information; Calculate the pulse energy resistance value based on the power battery system terminal voltage, pre-charging loop current, pre-charging time in the pre-charging characteristic information, the capacitor unit terminal voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, the pulse frequency, the pulse interval time in the pulse characteristic information, the current limiting unit instantaneous terminal voltage, the current limiting unit peak energy in the current limiting unit characteristic information, and the third loop model; Calculate the rated power characteristic value and the power overload resistance value based on the resistance operating condition information in the pre-charging characteristic information, the power battery system terminal voltage, the power safety factor and the power overload factor in the current limiting unit characteristic information, and the fourth loop model; The thermal stability resistance value is calculated based on the power battery system terminal voltage in the pre-charging characteristic information, the pre-charging time, the instantaneous terminal voltage of the current limiting unit in the current limiting unit characteristic information, the current limiting unit mass, the specific heat capacity of the current limiting unit material, the current limiting unit target temperature in the current limiting unit temperature characteristic information, the current limiting unit initial temperature, the current limiting unit operating temperature limit, and the fifth loop model.

6. The method according to claim 5, characterized in that The method further comprises: Calculate energy information based on the power battery system terminal voltage, pre-charge loop current, pre-charge time in the pre-charge characteristic information, the capacitor unit terminal voltage, the capacitor unit capacitance value in the capacitor unit characteristic information, the pulse frequency, and the pulse interval time in the pulse characteristic information, wherein the energy information includes the power battery supply energy and the capacitor unit storage energy; Calculating the pre-charging circuit pulse energy based on the energy supplied by the power battery and the energy stored in the capacitor unit; Determine the energy absorption state based on the pre-charging loop pulse energy and the current limiting unit peak energy in the current limiting unit characteristic information, and obtain a determination result; The pulse energy resistance value is selected and determined based on the judgment result.

7. The method according to claim 5, characterized in that The method further comprises: Determine the peak power of the current limiting unit based on the power battery system terminal voltage and resistance operating condition information in the pre-charge characteristic information; Determine a rated power characteristic value based on a power safety factor, a power overload factor, and a peak power of the current limiting unit in the characteristic information of the current limiting unit; Determine the power overload state based on the rated power characteristic value and the power safety factor and the power overload factor in the current limiting unit characteristic information, and obtain a determination result; The power overload resistance value is selected and determined based on the judgment result.

8. A current limiting unit selection device, characterized in that: The device comprises: An acquisition module, used for detecting a pre-charging loop voltage, and determining capacitor unit characteristic information, pre-charging characteristic information and pulse characteristic information according to the pre-charging loop voltage; a processing module, configured to determine a current limiting unit resistance target value and a rated power target value according to the pre-charging loop voltage, the capacitor unit characteristic information, the pre-charging characteristic information, and the pulse characteristic information; The execution module is used to select a target current limiting unit to control the power battery to perform pre-charging based on the target resistance value of the current limiting unit and the target rated power value.

9. A current limiting unit selection device, characterized in that: The device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the current limiting unit selection method according to any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the current limiting unit selection method according to any one of claims 1 to 7 are implemented.

Images