Battery pack initial parameter detection method, device, system, equipment and medium

Abstract

The present application relates to a method, device, system, equipment and medium for detecting initial parameters of a battery pack. The method comprises: obtaining the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are the voltage of the battery cells; obtaining the first-order equivalent circuit model of the battery pack, and calculating the initial parameters of the battery pack according to the electrical parameters and the first-order equivalent circuit model according to a preset algorithm, wherein the initial parameters include the battery internal resistance R0, the resistance value R1 corresponding to the first-order RC link of the battery equivalent circuit model, and the capacitance value C1 corresponding to the first-order RC link of the battery equivalent circuit model. This method can be used to obtain the initial parameters of each battery pack with the help of the battery pack offline detection process, avoiding the inconsistency of the battery cells and the influence of grouping, so that each battery pack can obtain more accurate initial parameters.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device, system, equipment and medium for detecting initial parameters of a battery pack. Background Art

[0002] During battery use, in order to ensure safe operation of the battery and extend the battery life, an equivalent circuit model is usually used to estimate the battery status such as SOC in real time. Therefore, the battery parameters must be obtained first.

[0003] The usual method for obtaining battery parameters is to sample several battery cells, perform a hybrid pulse power characteristic (HPPC) test on each battery cell, and use the HPPC test data to identify the battery parameters using methods such as recursive least squares or genetic algorithms.

[0004] However, after the cells are grouped, the inconsistency of the cells and the grouping will bring differences. The consistency of parameters such as voltage, charge, capacity, decay rate, internal resistance, etc. are key factors affecting the performance and service life of the battery pack. The battery parameters obtained by cell testing cannot well characterize the characteristics of the battery pack. Summary of the invention

[0005] Based on this, it is necessary to provide a battery pack initial parameter detection method, device, system, equipment and medium to address the above technical problems.

[0006] In order to achieve the above-mentioned and other purposes, the first aspect of the present application provides a method for detecting initial parameters of a battery pack, the method comprising:

[0007] Acquire electrical parameters of the battery pack and electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are voltages of the battery cells;

[0008] Obtain a first-order equivalent circuit model of the battery pack, and calculate initial parameters of the battery pack according to a preset algorithm based on the electrical parameters and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model.

[0009] In the battery pack initial parameter detection method provided in the above embodiment, the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack are obtained at a preset temperature, and the electrical parameters are the voltage of the battery cells; the first-order equivalent circuit model of the battery pack is obtained, and the initial parameters of the battery pack are calculated according to the electrical parameters and the first-order equivalent circuit model according to a preset algorithm, and the initial parameters include the battery internal resistance R0, the resistance value R1 corresponding to the first-order RC link of the battery equivalent circuit model, and the capacitance value C1 corresponding to the first-order RC link of the battery equivalent circuit model. Since the battery parameters are different at different temperatures, a preset temperature is set to facilitate the acquisition of the electrical parameters of the battery pack at different temperatures, and then the initial parameters of the battery pack are calculated according to the preset algorithm, so as to measure the initial parameters of the battery pack while ensuring the consistency of the battery pack.

[0010] In one embodiment, the obtaining of the first-order equivalent circuit model of the battery pack and calculating the initial parameters of the battery pack according to the electrical parameters and the first-order equivalent circuit model according to a preset algorithm include:

[0011] The formula for obtaining the first-order equivalent circuit model of the battery pack is:

[0012] U1=IR1·[1-exp(-t / τ1)];

[0013] U t =OCV(SOC)-IR0-U1;

[0014] The transfer function is obtained according to the formula:

[0015]

[0016] The transfer function is bilinearly transformed to obtain the terminal voltage function:

[0017] U t,k =(1-a1)OCV k +a1U t,k-1 +a2I k +a3I k-1 ;

[0018] Determine the output of the battery pack, the measurement vector and the vector to be estimated according to the terminal voltage function:

[0019] y k =U t,k ;

[0020]

[0021] θ k =[(1-a1)OCV k a1 a2 a3] T ;

[0022] Obtaining the initial parameters according to the output voltage, the output current, the output quantity, the measurement vector and the vector to be estimated by recursive least squares calculation;

[0023] Among them, U t is the terminal voltage of the battery, I is the charge and discharge current of the battery, OCV is the open circuit voltage of the battery, U1 is the terminal voltage of the capacitor-resistor network, R0 is the internal resistance of the battery, R1 is the resistance value corresponding to the first-order RC link of the battery equivalent circuit model, C1 is the capacitance value corresponding to the first-order RC link of the battery equivalent circuit model, I k is the system input current, U t,k is the system output voltage, y k is the output of the battery pack, is the measurement vector of the battery pack, θ k is the estimated vector of the battery pack, and a1, a2, and a3 are the corresponding coefficients.

[0024] In one embodiment, the obtaining of the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are the voltage of the battery cell, includes:

[0025] Controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging device program until the output voltage of the battery pack reaches a preset cut-off voltage, so as to depolarize the battery after charging and discharging;

[0026] During the period when the battery pack after battery polarization is subjected to a preset charge and discharge cycle, the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack are obtained.

[0027] In one embodiment, controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging device program includes:

[0028] The battery pack at a preset temperature is controlled to be charged with a first preset current value.

[0029] A second aspect of the present application provides a battery pack initial parameter detection device, comprising:

[0030] A battery electrical parameter acquisition module, used to acquire the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are the voltages of the battery cells;

[0031] An initial parameter acquisition module is used to obtain a first-order equivalent circuit model of the battery pack, and calculate the initial parameters of the battery pack according to a preset algorithm based on the electrical parameters and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model.

[0032] In the battery pack initial parameter detection device provided in the above embodiment, the battery electrical parameter acquisition module is used to acquire the corresponding electrical parameters at different temperatures, and then the initial parameters of the battery pack are acquired through a preset algorithm in the initial parameter acquisition module.

[0033] In one embodiment, the initial parameter acquisition module is configured as follows:

[0034] The formula for obtaining the first-order equivalent circuit model of the battery pack is:

[0035] U1=IR1·[1-exp(-t / τ1)];

[0036] U t =OCV(SOC)-IR0-U1;

[0037] The transfer function is obtained according to the formula:

[0038]

[0039] The transfer function is bilinearly transformed to obtain the terminal voltage function:

[0040] U t,k =(1-a1)OCV k +a1U t,k-1 +a2I k +a3I k-1 ;

[0041] Determine the output of the battery pack, the measurement vector and the vector to be estimated according to the terminal voltage function:

[0042] y k =U t,k ;

[0043]

[0044] θ k =[(1-a1)OCV k a1 a2 a3] T ;

[0045] Obtaining the initial parameters according to the output voltage, the output current, the output quantity, the measurement vector and the vector to be estimated by recursive least squares calculation;

[0046] Among them, U t is the terminal voltage of the battery, I is the charge and discharge current of the battery, OCV is the open circuit voltage of the battery, U1 is the terminal voltage of the capacitor-resistor network, R0 is the internal resistance of the battery, R1 is the resistance value corresponding to the first-order RC link of the battery equivalent circuit model, C1 is the capacitance value corresponding to the first-order RC link of the battery equivalent circuit model, I k is the system input current, U t,k is the system output voltage, y k is the output of the battery pack, is the measurement vector of the battery pack, θ k is the estimated vector of the battery pack, and a1, a2, and a3 are the corresponding coefficients.

[0047] In one embodiment, the initial parameter acquisition module is configured as follows:

[0048] Controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging device program until the output voltage of the battery pack reaches a preset cut-off voltage;

[0049] During the period when the battery pack after battery polarization is subjected to a preset charge and discharge cycle, the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack are obtained.

[0050] A third aspect of the present application provides a battery pack initial parameter detection system, comprising:

[0051] The temperature chamber is used to provide a constant temperature environment with a preset temperature for the battery pack placed inside it;

[0052] A battery charging and discharging device, used to charge or discharge the battery pack; and

[0053] A battery pack initial parameter detection device as described in any of the embodiments of the present application.

[0054] In the battery pack initial parameter detection system provided in the above embodiment, since the battery parameters are different at different temperatures, the battery parameters are obtained to obtain the battery parameters at different temperatures. However, the battery will have a temperature rise during the charging and discharging process, so the battery pack is generally placed in a temperature bin so that the battery pack can keep the temperature constant at a preset temperature. Then, the battery electrical parameter acquisition module is used to acquire the electrical parameters, and then the battery pack is discharged or charged by the battery charging and discharging device, and then the initial parameter acquisition module is used to acquire the initial parameters of the battery pack according to the preset algorithm.

[0055] A fourth aspect of the present application provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0056] Acquire electrical parameters of the battery pack and electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are voltages of the battery cells;

[0057] Obtain a first-order equivalent circuit model of the battery pack, and calculate initial parameters of the battery pack according to a preset algorithm based on the electrical parameters and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model.

[0058] A fifth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the following steps are implemented:

[0059] Acquire electrical parameters of the battery pack and electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are voltages of the battery cells;

[0060] Obtain a first-order equivalent circuit model of the battery pack, and calculate initial parameters of the battery pack according to a preset algorithm based on the electrical parameters and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model.

[0061] The above-mentioned embodiment can obtain initial parameters for each battery pack by means of the battery pack offline detection process, thereby avoiding the inconsistency of the battery cells and the influence of grouping, so that each battery pack can obtain more accurate initial parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0063] Figure 1 A schematic diagram of a method for detecting initial parameters of a battery pack provided in the first embodiment of the present application;

[0064] Figure 2 A schematic diagram of a flow chart of a method for detecting initial parameters of a battery pack provided in the second embodiment of the present application;

[0065] Figure 3 A schematic diagram of a method for detecting initial parameters of a battery pack provided in the third embodiment of the present application;

[0066] Figure 4A schematic diagram of a flow chart of a method for detecting initial parameters of a battery pack provided in the fourth embodiment of the present application;

[0067] Figure 5 A structural diagram of a battery pack initial parameter detection system provided in one embodiment of the present application;

[0068] Description of reference numerals:

[0069] 10. Battery electrical parameter acquisition module; 20. Initial parameter acquisition module; 30. Temperature chamber; 40. Battery charging and discharging equipment. DETAILED DESCRIPTION

[0070] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0072] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0073] As described in the background technology, the method of obtaining battery parameters in the prior art is to sample several battery cells, perform HPPC tests on each battery cell, and use HPPC test data to identify battery parameters using methods such as recursive least squares or genetic algorithms. However, battery cells are inconsistent, and the inconsistency increases during use, so that the battery parameters obtained by the battery cell test cannot well characterize the characteristics of the battery pack.

[0074] For the above reasons, please refer to Figure 1 In some embodiments of the present application, a method for detecting initial parameters of a battery pack is provided, comprising the following steps:

[0075] S200: Acquire electrical parameters of the battery pack and electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are voltages of the battery cells;

[0076] S400: Obtain a first-order equivalent circuit model of the battery pack, and calculate initial parameters of the battery pack according to a preset algorithm based on the electrical parameters and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model.

[0077] Through the above technical solution, the preset temperature can be -20°C to 60°C. For example, in some embodiments, the preset temperature can be at intervals of 10°C, i.e., -20°C, -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, and 60°C. The battery parameters of the battery pack are different at the preset temperature. First, the output current and output voltage of the battery pack at the preset temperature and the output voltage of all battery cells are obtained, and then the initial parameters of the battery pack are calculated using the preset algorithm.

[0078] As an example, see Figure 2 In some embodiments of the present application, the obtaining of the first-order equivalent circuit model of the battery pack and the calculation of the initial parameters of the battery pack according to the electrical parameters and the first-order equivalent circuit model according to a preset algorithm include:

[0079] S410: Obtain a formula for a first-order equivalent circuit model of the battery pack:

[0080] U1=IR1·[1-exp(-t / τ1)];

[0081] U t =OCV(SOC)-IR0-U1;

[0082] S420: Obtain the transfer function according to the formula:

[0083]

[0084] S430: Perform bilinear transformation on the transfer function to obtain a terminal voltage function:

[0085] U t,k =(1-a1)OCV k +a1U t,k-1 +a2I k +a3I k-1 ;

[0086] S440: Determine the output of the battery pack, the measurement vector, and the vector to be estimated according to the terminal voltage function:

[0087] y k =U t,k ;

[0088]

[0089] θ k =[(1-a1)OCV k a1 a2 a3] T ;

[0090] S450: Obtaining the initial parameters according to the output voltage, the output current, the output quantity, the measurement vector and the vector to be estimated by recursive least squares calculation;

[0091] Among them, U t is the terminal voltage of the battery, I is the charge and discharge current of the battery, OCV is the open circuit voltage of the battery, U1 is the terminal voltage of the capacitor-resistor network, R0 is the internal resistance of the battery, R1 is the resistance value corresponding to the first-order RC link of the battery equivalent circuit model, C1 is the capacitance value corresponding to the first-order RC link of the battery equivalent circuit model, I k is the system input current, U t,k is the system output voltage, y k is the output of the battery pack, is the measurement vector of the battery pack, θ k is the estimated vector of the battery pack, and a1, a2, and a3 are the corresponding coefficients.

[0092] Specifically, in the above formula, OCV (Open circuit voltage) is the open circuit voltage, which refers to the potential difference between the two electrodes when the battery is open without discharging.

[0093]

[0094]

[0095]

[0096] As an example, see Figure 3 In some embodiments of the present application, the step of obtaining the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are the voltage of the battery cell, includes:

[0097] Controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging device program until the output voltage of the battery pack reaches a preset cut-off voltage, so as to depolarize the battery after charging and discharging;

[0098] During the period when the battery pack after battery polarization is subjected to a preset charge and discharge cycle, the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack are obtained.

[0099] Specifically, during the offline inspection of the battery pack, since the battery will have a temperature rise during the charging and discharging process, in order to adjust the temperature of the battery pack to the preset temperature, the battery pack is placed in a temperature chamber 30 at a preset temperature and is stationary for a first preset time. For example, in some embodiments, the first preset time can be 8h-24h, specifically 8h, 12h, 16h, 20h or 24h. Then a preset discharge device program is set to control the battery pack to charge and discharge until the output voltage of the battery pack reaches the preset cut-off voltage and then stops and remains stationary for a second preset time in order to depolarize the battery. For example, in some embodiments, the second preset time can be 0.5h-2h, specifically 0.5h, 1h, 1.5h or 2h. When a current passes through the battery, the phenomenon that the potential deviates from the equilibrium potential is called electrode polarization, so it is necessary to depolarize the battery to reach a balanced state. After depolarizing the battery, a preset charge and discharge condition cycle is performed, and the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack are obtained. For example, in some embodiments, the preset charge and discharge operating condition may be a typical charge and discharge operating condition of a battery system, such as a FUDS operating condition.

[0100] As an example, see Figure 4 In some embodiments of the present application, the step of controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging device program includes:

[0101] The battery pack at the preset temperature is controlled to be charged with a first preset current value. For example, in some embodiments, the first preset current value may be 0.5C, 1C or 1.5C.

[0102] It should be understood that, unless otherwise specified herein, the execution of the steps described is not strictly limited in order, and the steps may be executed in other orders. Moreover, at least a portion of the steps described may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but may be executed at different times, and the execution order of these sub-steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0103] Please refer to Figure 5 In some embodiments of the present application, a battery pack initial parameter detection device is provided, comprising:

[0104] A battery electrical parameter acquisition module 10, used to acquire electrical parameters of the battery pack and electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are the voltages of the battery cells;

[0105] The initial parameter acquisition module 20 is used to obtain the first-order equivalent circuit model of the battery pack, and calculate the initial parameters of the battery pack according to the electrical parameters and the first-order equivalent circuit model according to a preset algorithm. The initial parameters include the battery internal resistance R0, the resistance value R1 corresponding to the first-order RC link of the battery equivalent circuit model, and the capacitance value C1 corresponding to the first-order RC link of the battery equivalent circuit model.

[0106] In the battery pack initial parameter detection device provided in the above embodiment, the battery electrical parameter acquisition module 10 acquires the corresponding electrical parameters at different temperatures, and then the initial parameters of the battery pack are obtained through the preset algorithm in the initial parameter acquisition module 20 .

[0107] In one embodiment, the initial parameter acquisition module is configured as follows:

[0108] The formula for obtaining the first-order equivalent circuit model of the battery pack is:

[0109] U1=IR1·[1-exp(-t / τ1)];

[0110] U t =OCV(SOC)-IR0-U1;

[0111] The transfer function is obtained according to the formula:

[0112]

[0113] The transfer function is bilinearly transformed to obtain the terminal voltage function:

[0114] U t,k =(1-a1)OCV k +a1U t,k-1 +a2I k +a3I k-1 ;

[0115] Determine the output of the battery pack, the measurement vector and the vector to be estimated according to the terminal voltage function:

[0116] y k =U t,k ;

[0117]

[0118] θ k =[(1-a1)OCV k a1 a2 a3]T ;

[0119] Obtaining the initial parameters according to the output voltage, the output current, the output quantity, the measurement vector and the vector to be estimated by recursive least squares calculation;

[0120] Among them, U t is the terminal voltage of the battery, I is the charge and discharge current of the battery, OCV is the open circuit voltage of the battery, U1 is the terminal voltage of the capacitor-resistor network, R0 is the internal resistance of the battery, R1 is the resistance value corresponding to the first-order RC link of the battery equivalent circuit model, C1 is the capacitance value corresponding to the first-order RC link of the battery equivalent circuit model, I k is the system input current, U t,k is the system output voltage, y k is the output of the battery pack, is the measurement vector of the battery pack, θ k is the estimated vector of the battery pack, and a1, a2, and a3 are the corresponding coefficients.

[0121] In some embodiments of the present application, the initial parameter acquisition module is configured as follows:

[0122] Controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging device program until the output voltage of the battery pack reaches a preset cut-off voltage;

[0123] During the preset charge and discharge cycle of the battery pack after battery polarization is removed, the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack are obtained, and the electrical parameters are the voltages of the battery cells.

[0124] Please continue to refer to Figure 5 In some embodiments of the present application, a battery pack initial parameter detection system is provided, comprising:

[0125] The temperature chamber 30 is used to provide a constant temperature environment of a preset temperature for the battery pack placed therein;

[0126] A battery charging and discharging device 40, used to charge or discharge the battery pack; and

[0127] A battery pack initial parameter detection device as described in any of the embodiments of the present application.

[0128] Specifically, in the battery pack initial parameter detection system provided by the above embodiment, since the battery parameters are different at different temperatures, the battery parameters are obtained to obtain the battery parameters at different temperatures, but the battery temperature rises during the charging and discharging process, so the battery pack is generally placed in the temperature chamber 30 so that the temperature of the battery pack can be kept constant at a preset temperature. Then, the battery electrical parameter acquisition module 10 acquires the electrical parameters, and then the battery pack is discharged or charged by the battery charging and discharging device 40, and then the initial parameter acquisition module 20 acquires the initial parameters of the battery pack according to the preset algorithm.

[0129] In some embodiments of the present application, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0130] Acquire electrical parameters of the battery pack and electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are voltages of the battery cells;

[0131] Obtain a first-order equivalent circuit model of the battery pack, and calculate initial parameters of the battery pack according to a preset algorithm based on the electrical parameters and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model.

[0132] In some embodiments of the present application, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0133] Acquire electrical parameters of the battery pack and electrical parameters of each battery cell in the battery pack at a preset temperature, wherein the electrical parameters are voltages of the battery cells;

[0134] Obtain a first-order equivalent circuit model of the battery pack, and calculate initial parameters of the battery pack according to a preset algorithm based on the electrical parameters and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model.

[0135] The above-mentioned embodiment can obtain initial parameters for each battery pack by means of the battery pack offline detection process, thereby avoiding the inconsistency of the battery cells and the influence of grouping, so that each battery pack can obtain more accurate initial parameters.

[0136] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0137] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0138] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0139] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0140] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for detecting initial parameters of a battery pack, characterized in that: The method comprises: Acquire the electrical parameters of the battery pack at a preset temperature and the electrical parameters of each battery cell in the battery pack, wherein the electrical parameter of the battery cell is the output voltage of the battery cell, and the electrical parameter of the battery pack is the output current and output voltage of the battery pack at the preset temperature; Obtaining a first-order equivalent circuit model of the battery pack, and calculating initial parameters of the battery pack according to a preset algorithm based on the electrical parameters of the battery pack and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model; The obtaining of the first-order equivalent circuit model of the battery pack and calculating the initial parameters of the battery pack according to the electrical parameters of the battery pack and the first-order equivalent circuit model according to a preset algorithm include: The formula for obtaining the first-order equivalent circuit model of the battery pack is: U1=IR1·[1-exp(-t / τ1)]; The t =OCV(SOC)-IR0-U1; The transfer function is obtained according to the formula: The transfer function is bilinearly transformed to obtain the terminal voltage function: U t,k =(1-a1)OCV k +a1U t,k-1 +a2I k +a3I k-1 ; Determine the output of the battery pack, the measurement vector and the vector to be estimated according to the terminal voltage function: y k =U t,k ; <h2 style=";text-align:left;direction:ltr">θ<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> (1-a1)OCV<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> a1 a2 a3<h2 style=";text-align:left;direction:ltr"> T <h2 style=";text-align:left;direction:ltr"> ; Among them, U t is the terminal voltage of the battery pack, I is the charge and discharge current of the battery, OCV is the open circuit voltage of the battery, U1 is the voltage of the first-order RC link of the battery equivalent circuit model, R0 is the internal resistance of the battery, R1 is the resistance value corresponding to the first-order RC link of the battery equivalent circuit model, C1 is the capacitance value corresponding to the first-order RC link of the battery equivalent circuit model, I k is the system input current, U t,k is the system output voltage, y k is the output of the battery pack, is the measurement vector of the battery pack, θ k is the estimated vector of the battery pack, a1, a2, a3 are the corresponding coefficients; The initial parameters are obtained by performing a recursive least squares calculation according to the output voltage, the output current, the output quantity, the measurement vector and the vector to be estimated.

2. The detection method according to claim 1, characterized in that: The obtaining of the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack at a preset temperature includes: Controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging device program until the output voltage of the battery pack reaches a preset cut-off voltage; During the period when the battery pack after battery polarization is subjected to a preset charge and discharge cycle, the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack are obtained.

3. The detection method according to claim 2, characterized in that: The step of controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging equipment program includes: The battery pack at a preset temperature is controlled to be charged with a first preset current value.

4. A battery pack initial parameter detection device, characterized in that: include: A battery electrical parameter acquisition module, used to acquire the electrical parameters of the battery pack at a preset temperature and the electrical parameters of each battery cell in the battery pack, wherein the electrical parameter of the battery cell is the output voltage of the battery cell, and the electrical parameter of the battery pack is the output current and output voltage of the battery pack at a preset temperature; An initial parameter acquisition module, used to acquire a first-order equivalent circuit model of the battery pack, and calculate the initial parameters of the battery pack according to a preset algorithm based on the electrical parameters of the battery pack and the first-order equivalent circuit model, wherein the initial parameters include a battery internal resistance R0, a resistance value R1 corresponding to a first-order RC link of the battery equivalent circuit model, and a capacitance value C1 corresponding to a first-order RC link of the battery equivalent circuit model; The initial parameter acquisition module is configured as follows: The formula for obtaining the first-order equivalent circuit model of the battery pack is: U1=IR1·[1-exp(-t / τ1)]; The t =OCV(SOC)-IR0-U1; The transfer function is obtained according to the formula: The transfer function is bilinearly transformed to obtain the terminal voltage function: U t,k =(1-a1)OCV k +a1U t,k-1 +a2I k +a3I k-1 ; Determine the output of the battery pack, the measurement vector and the vector to be estimated according to the terminal voltage function: y k =U t,k ; <h2 style=";text-align:left;direction:ltr">θ<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> (1-a1)OCV<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> a1 a2 a3<h2 style=";text-align:left;direction:ltr"> T <h2 style=";text-align:left;direction:ltr"> ; Among them, U t is the terminal voltage of the battery pack, I is the charge and discharge current of the battery, OCV is the open circuit voltage of the battery, U1 is the voltage of the first-order RC link of the battery equivalent circuit model, R0 is the internal resistance of the battery, R1 is the resistance value corresponding to the first-order RC link of the battery equivalent circuit model, C1 is the capacitance value corresponding to the first-order RC link of the battery equivalent circuit model, I k is the system input current, U t,k is the system output voltage, y k is the output of the battery pack, is the measurement vector of the battery pack, θ k is the estimated vector of the battery pack, a1, a2, a3 are the corresponding coefficients; The initial parameters are obtained by performing a recursive least squares calculation according to the output voltage, the output current, the output quantity, the measurement vector and the vector to be estimated.

5. The detection device according to claim 4, characterized in that: The initial parameter acquisition module is configured as follows: Controlling the charging of the battery pack at a preset temperature according to a preset charging and discharging device program until the output voltage of the battery pack reaches a preset cut-off voltage; During the period when the battery pack after battery polarization is subjected to a preset charge and discharge cycle, the electrical parameters of the battery pack and the electrical parameters of each battery cell in the battery pack are obtained.

6. A battery pack initial parameter detection system, characterized in that: include: The temperature chamber is used to provide a constant temperature environment with a preset temperature for the battery pack placed inside it; A battery charging and discharging device, used to charge or discharge the battery pack; as well as The battery pack initial parameter detection device as described in claim 4 or 5.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 3 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 3 are implemented.

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