Lithium Battery Parameter Identification Method, Device, Electronic Device and Storage Medium

Abstract

The present application discloses a method, device, electronic device and storage medium for identifying lithium battery parameters, relating to lithium battery technology. The method includes: determining the voltage-current relationship in a resistor-capacitor (R-C) equivalent circuit model, where the R-C equivalent circuit model includes at least two resistor units, and one resistor unit corresponds to at least one parameter to be identified; determining at least one parameter to be identified for the resistor unit corresponding to each time scale based on the time-frequency characteristics of the R-C equivalent circuit model; calculating at least one parameter to be identified for the resistor unit corresponding to each time scale respectively based on the voltage-current relationship, and obtaining the parameter identification result of each parameter to be identified. By analyzing and calculating the parameters to be identified for each resistor unit by dividing them into corresponding time scales, the present application can obtain the parameter identification results of the corresponding parameters to be identified at each time scale, which can improve the parameter identification accuracy and achieve the beneficial effect of improving the lithium battery parameter identification accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, and in particular to a method, device, electronic device and storage medium for identifying lithium battery parameters. Background Art

[0002] With the increasingly wide application of lithium batteries, parameter identification of lithium batteries is an important link for evaluating the performance indicators of lithium batteries. The accuracy of the lithium battery parameter identification results is of great significance for the performance optimization of lithium batteries.

[0003] The conventional method for identifying lithium battery parameters is generally to formulate a fitting function for temperature and the state of charge (SOC) of the battery in advance under a certain standard working condition (such as pulse or constant power working condition), so as to directly look up the current state of charge of the battery according to the current temperature under the actual working condition, and then identify and calculate the lithium battery parameters based on the current temperature, the current state of charge and in combination with a traditional identification algorithm (such as the least squares method) to obtain the current identification result of the lithium battery parameters.

[0004] However, due to the differences between the actual working condition and the standard working condition, even at the same temperature and SOC, the identification results obtained by the traditional identification algorithm may also have large differences, thereby generating errors and reducing the accuracy of the lithium battery parameter identification. Summary of the Invention

[0005] The present application provides a method, device, electronic device and storage medium for identifying lithium battery parameters, which can improve the existing solutions for identifying lithium battery parameters.

[0006] In a first aspect, the present application provides a method for identifying lithium battery parameters, including: determining the voltage-current relationship in a resistor-capacitor (R-C) equivalent circuit model, where the RC equivalent circuit model includes at least two resistor units, and one resistor unit corresponds to at least one parameter to be identified; determining at least one parameter to be identified of the resistor unit corresponding to each time scale based on the time-frequency characteristics of the RC equivalent circuit model; calculating at least one parameter to be identified of the resistor unit corresponding to each time scale respectively based on the voltage-current relationship to obtain the parameter identification result of each parameter to be identified.

[0007] Second aspect, the present application provides a lithium battery parameter identification device, and the device includes: a first determination module, configured to determine the voltage-current relationship in a resistor-capacitor (R-C) equivalent circuit model, where the R-C equivalent circuit model includes at least two resistor units, and one resistor unit corresponds to at least one parameter to be identified; a second determination module, configured to determine at least one parameter to be identified of the resistor unit corresponding to each time scale based on the time-frequency characteristics of the R-C equivalent circuit model; a parameter calculation module, configured to calculate at least one parameter to be identified of the resistor unit corresponding to each time scale respectively based on the voltage-current relationship, and obtain a parameter identification result of each parameter to be identified.

[0008] Third aspect, the present application further provides an electronic device, and the electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the lithium battery parameter identification method according to any embodiment of the present application.

[0009] Fourth aspect, the present application further provides a computer-readable storage medium, and the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the lithium battery parameter identification method according to any embodiment of the present application when executed.

[0010] The lithium battery parameter identification solution provided by the embodiments of the present application first determines the voltage-current relationship in a resistor-capacitor (R-C) equivalent circuit model, where the R-C equivalent circuit model includes at least two resistor units, and one resistor unit corresponds to at least one parameter to be identified; then determines at least one parameter to be identified of the resistor unit corresponding to each time scale based on the time-frequency characteristics of the R-C equivalent circuit model; and finally calculates at least one parameter to be identified of the resistor unit corresponding to each time scale respectively based on the voltage-current relationship, and obtains a parameter identification result of each parameter to be identified. By dividing the parameters to be identified of each resistor unit into corresponding time scales for analysis and calculation, this embodiment can obtain the parameter identification results of the corresponding parameters to be identified at each time scale, improve the parameter identification accuracy, and achieve the beneficial effect of improving the lithium battery parameter identification accuracy.

[0011] It should be noted that the above computer instructions can be stored in whole or in part on a computer-readable storage medium. Wherein, the computer-readable storage medium can be packaged together with the processor of the lithium battery parameter identification device, or can be packaged separately from the processor of the lithium battery parameter identification device, and the present application does not make any limitation thereto.

[0012] For the descriptions of the second, third, and fourth aspects in this application, reference can be made to the detailed description of the first aspect; and for the beneficial effects of the descriptions of the second, third, and fourth aspects, reference can be made to the analysis of the beneficial effects of the first aspect, which will not be elaborated here.

[0013] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of this application, nor is it used to limit the scope of this application. Other features of this application will become easily understandable through the following description.

[0014] It can be understood that before using the technical solutions disclosed in the embodiments of this application, the types, usage scopes, usage scenarios, etc. of the personal information involved in this application should be informed to the users and the users' authorization should be obtained in an appropriate manner in accordance with relevant laws and regulations. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0016] Figure 1 is a flowchart of a lithium battery parameter identification method provided by an embodiment of this application.

[0017] Figure 2 is another flowchart of a lithium battery parameter identification method provided by an embodiment of this application.

[0018] Figure 3a is a schematic structural diagram of a second-order RC equivalent circuit model provided by an embodiment of this application.

[0019] Figure 3b is a schematic diagram of the multi-time scale effect of a second-order RC equivalent circuit model provided by an embodiment of this application.

[0020] Figure 4 is a schematic structural diagram of a lithium battery parameter identification device provided by an embodiment of this application.

[0021] Figure 5 is a schematic structural diagram of an electronic device for a lithium battery parameter identification method provided by an embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To enable those skilled in the art to better understand the solution of this application, the technical solution in this application will be clearly and completely described below in conjunction with the accompanying drawings in this embodiment. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0023] It should be noted that the terms "first", "second", etc. in the specification, claims and above-mentioned drawings of this application are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of this application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0024] The following further details this application in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described here are only used to explain this application, rather than limiting this application. Additionally, it should be noted that for the convenience of description, only parts related to this application rather than all structures are shown in the accompanying drawings.

[0025] Figure 1 It is a schematic flowchart of a method for identifying lithium battery parameters provided by an embodiment of this application. This embodiment is applicable to the situation of identifying at least one lithium battery parameter included during the actual operation of a lithium battery. This method can be executed by a lithium battery parameter identification device, which can be implemented in the form of hardware and / or software and integrated in an electronic device that executes this method. Please refer to Figure 1 , the method of this embodiment includes but is not limited to the following steps:

[0026] S110. Determine the voltage-current relationship in the resistor-capacitor (R-C) equivalent circuit model.

[0027] To facilitate the identification of lithium battery parameters, this embodiment can represent the complex internal circuit structure of a lithium battery through a resistor-capacitor (R-C) equivalent circuit model. Under the condition that the input and output remain unchanged, a simpler RC equivalent circuit model is used to replace the original circuit model, making the analysis and calculation of the circuit model more concise and convenient, so as to improve the analysis efficiency of the circuit model.

[0028] The RC equivalent circuit model provided in this embodiment may include at least two resistor units. Among them, when the RC equivalent circuit model includes two resistor units, one resistor unit is implemented by a resistor, and the other resistor unit is implemented by a parallel connection of a resistor and a capacitor. This kind of RC equivalent circuit model can be called a first-order equivalent circuit model; when the RC equivalent circuit model includes three resistor units, one resistor unit is implemented by a resistor, and the other two resistor units are respectively implemented by a parallel connection of a resistor and a capacitor. This kind of RC equivalent circuit model can be called a second-order equivalent circuit model; when the RC equivalent circuit model includes four resistor units, one resistor unit is implemented by a resistor, and the other three resistor units are respectively implemented by a parallel connection of a resistor and a capacitor. This kind of RC equivalent circuit model can be called a third-order equivalent circuit model; optionally, the RC equivalent circuit model can also be an N-order equivalent circuit model, where N represents the number of parallel connections of resistors and capacitors. The specific implementation form of the RC equivalent circuit model depends on the actual circuit requirements and is not limited here.

[0029] In this embodiment, one resistor unit corresponds to at least one parameter to be identified. The parameter to be identified is a parameter that can reflect the performance index of the lithium-ion battery. The purpose of identifying the parameters of the lithium-ion battery is to obtain the change of each parameter during the entire charging and discharging process of the lithium-ion battery, so as to help predict the state of charge of the lithium battery according to the change results of each parameter (for example, predict how long the current battery power can support the user), or help optimize the performance of the lithium battery, etc. Therefore, it is of great significance to accurately identify each parameter in the lithium battery.

[0030] The number of parameters to be identified is related to the order of the RC equivalent circuit model. The relationship between the number of parameters to be identified and the order of the RC equivalent circuit model can be expressed as M = 2N + 1, where M represents the number of parameters to be identified and N represents the order of the RC equivalent circuit model. Exemplarily, when it is a first-order RC equivalent circuit model, the parameters to be identified include three; when it is a second-order RC equivalent circuit model, the parameters to be identified include five, and so on. The specific number of parameters to be identified is not limited here.

[0031] S120. Determine at least one parameter to be identified of the resistor unit corresponding to each time scale based on the time-frequency characteristics of the RC equivalent circuit model.

[0032] The time-frequency characteristics of the RC equivalent circuit model are used to characterize the changes with time and the corresponding frequency changes of the RC equivalent circuit model during the charge and discharge processes. Since the internal physical and chemical processes are relatively complex during the actual charge and discharge processes of lithium batteries, and various reaction processes also differ in time scales. Through the analysis of the time-frequency characteristics of the RC equivalent circuit model in this embodiment, it can be seen that the voltage response of the battery under the action of current includes a fast response link and a slow change link, that is, the dynamic characteristics of the battery are distributed within a relatively wide frequency range. To adapt to this situation, it can be found that according to the different orders of the RC equivalent circuit, each RC link has significantly different time constants. Taking the second-order RC equivalent circuit model as an example, from the time-domain perspective, the time constants of the two RC links are on different time scales. Exemplarily, in a second-order RC equivalent circuit model under a certain working condition, the time constant of the first RC link can be 4.2 seconds. The time constant of the second RC link can be 506 seconds, etc. The specific time constant of each RC link is subject to the time-frequency characteristics of the corresponding RC equivalent circuit model and is not limited here.

[0033] In this embodiment, the method for determining at least one parameter to be identified of the resistance unit corresponding to each time scale based on the time-frequency characteristics of the RC equivalent circuit model can be, taking the RC equivalent circuit model as a second-order RC equivalent circuit model as an example. The second-order RC equivalent circuit model includes a first resistance unit, a second resistance unit, and a third resistance unit. Among them, the first resistance unit includes a first resistor; the second resistance unit includes a second resistor and a first capacitor connected in parallel, and the third resistance unit includes a third resistor and a second capacitor connected in parallel. That is, there are two RCs in the order RC equivalent circuit model. Among them, the first capacitor can reflect the sudden rise or fall of the voltage under current excitation, and the corresponding frequency is 310 Hz; the second resistance unit is the frequency response range of the charge transfer process of the lithium battery between 0.2 Hz and several hundred Hz; the third resistance unit is that the diffusion process of charges mainly determines the frequency response process below 0.2 Hz. Corresponding to the second-order RC equivalent circuit model, from the time-domain perspective, the time constants of the two RC links should be on different time scales. Furthermore, the second-order RC equivalent circuit model can be determined as three time scales according to the time-frequency characteristics. For example, it can include a first time scale for calculating the change of the parameter to be identified corresponding to the first resistance unit; a second time scale for calculating the change of the parameter to be identified corresponding to the second resistance unit; a third time scale for calculating the change of the parameter to be identified corresponding to the third resistance unit. Optionally, when the RC equivalent circuit model is a first-order RC equivalent circuit model, it can be divided into a first time scale and a second time scale, etc. The specific number of time scales determined for the RC equivalent circuit model is related to the order of the RC equivalent circuit model and is not limited here.

[0034] S130. Calculate at least one parameter to be identified of the resistance unit corresponding to each time scale based on the voltage-current relationship, and obtain the parameter identification result of each parameter to be identified.

[0035] After determining at least one parameter to be identified of the resistance unit corresponding to each time scale based on step S120, calculate each parameter to be identified on the corresponding time scale in combination with the voltage-current relationship in the RC equivalent circuit model obtained in step S110. The specific calculation method can be to transform the voltage-current relationship on the corresponding time scale in combination with the least squares method, and express each parameter to be identified in the form of the corresponding least squares, and then solve and calculate the least squares form corresponding to each parameter to be identified to obtain the parameter identification result of the parameter to be identified; optionally, it can also be based on mathematical methods such as integral algorithms and / or differential algorithms at each time scale to calculate at least one parameter to be identified at each time scale in combination with the voltage-current relationship. The specific method of calculating the parameter to be identified on the corresponding time scale by the voltage-current relationship is not limited here.

[0036] The lithium battery parameter identification method provided in this embodiment first determines the voltage-current relationship in the resistance R-capacitance C equivalent circuit model. The RC equivalent circuit model includes at least two resistance units, and one resistance unit corresponds to at least one parameter to be identified; then determines at least one parameter to be identified of the resistance unit corresponding to each time scale based on the time-frequency characteristics of the RC equivalent circuit model; finally, calculates at least one parameter to be identified of the resistance unit corresponding to each time scale based on the voltage-current relationship, and obtains the parameter identification result of each parameter to be identified. By dividing the parameters to be identified of each resistance unit into the corresponding time scales for analysis and calculation, this embodiment can obtain the parameter identification results of the corresponding parameters to be identified at each time scale, improve the parameter identification accuracy, and achieve the beneficial effect of improving the lithium battery parameter identification accuracy.

[0037] Figure 2 It is another process schematic diagram of the lithium battery parameter identification method provided by the embodiments of the present application. The embodiments of the present application are optimized on the basis of the above embodiments. Specifically, the optimization is: this embodiment elaborates on the relevant processes of "determining at least one parameter to be identified of the resistance unit corresponding to each time scale based on the time-frequency characteristics of the RC equivalent circuit model" and "calculating at least one parameter to be identified of the resistance unit corresponding to each time scale based on the voltage-current relationship, and obtaining the parameter identification result of each parameter to be identified" in the above embodiments.

[0038] First, please refer to Figure 3a , Figure 3aIt is a schematic structural diagram of a second-order RC equivalent circuit model provided by an embodiment of the present application. In this embodiment, the RC equivalent circuit model is used as a second-order RC equivalent circuit model to elaborate on the solution in detail. In this embodiment, the second-order RC equivalent circuit model includes a first resistor unit, a second resistor unit, and a third resistor unit. Among them, the first resistor unit includes a first resistor, and the first resistor is used to represent the ohmic resistance inside the battery; the second resistor unit includes a second resistor and a first capacitor connected in parallel, and the third resistor unit includes a third resistor and a second capacitor connected in parallel. In Figure 3a where, i represents the input current; u oc represents the open-circuit voltage of the battery; u t represents the battery terminal voltage; u s represents the voltage across the second resistor unit; u p represents the voltage across the third resistor unit. Among them, R s and C s represent the charge transfer process; R p and C p represent the charge diffusion process.

[0039] Specifically, referring to Figure 2 , the lithium battery parameter identification method provided by this embodiment includes but is not limited to the following steps:

[0040] S210. Determine the voltage-current relationship in the second-order resistor R-capacitor C equivalent circuit model.

[0041] In Figure 3a , combining Kirchhoff's law and component characteristics, the voltage-current relationship in the circuit can be listed as shown in the following formula (1):

[0042] u oc (t) = iR0 + u s + u p + u t (t) = F(SOC(t))

[0043]

[0044] In the above formula (1), SOC(t) indicates the state of charge of the lithium battery at the current time and is used to reflect the remaining capacity of the lithium battery. F(SOC(t)) indicates a function of SOC(t).

[0045] S220. In the first frequency range, determine that the parameter to be identified corresponding to the first time scale is the first resistor parameter corresponding to the first resistor in the first resistor unit.

[0046] In the current steps S220 to S222, in order to determine at least one parameter to be identified of the resistance unit corresponding to each time scale based on the time-frequency characteristics of the RC equivalent circuit model. The time-frequency characteristics mentioned in this embodiment include time scale characteristics and frequency characteristics. Specifically, when the RC equivalent circuit model in this embodiment is a second-order RC equivalent circuit model, the corresponding time scale characteristics include a first time scale, a second time scale, and a third time scale; the frequency characteristics include a first frequency range, a second frequency range, and a third frequency range, the first frequency range is higher than the second frequency range, and the second frequency range is higher than the third frequency range.

[0047] In this embodiment, the reason for dividing the time scale characteristics of the second-order RC equivalent circuit model into the above three time scales and dividing the frequency characteristics into the above three frequency ranges is as follows. Please refer to Figure 3b , Figure 3b which is a schematic diagram of the multi-time scale effect of the second-order RC equivalent circuit model provided by the embodiment of the present application.

[0048] In the figure, the second-order RC equivalent circuit model is represented in the complex form of impedance. Among them, the abscissa represents the real part of the complex form, and the ordinate represents the imaginary part of the complex form. The ohmic resistance R0 can reflect the steep rise or fall of the voltage under current excitation, and the corresponding frequency is 310 Hz; the frequency response range of the charge transfer process of the lithium battery is between 0.2 Hz and several hundred Hz, which corresponds to the part of the second resistance unit; and the charge diffusion process mainly determines the frequency response process below 0.2 Hz, which is the part corresponding to the third resistance unit. Corresponding to the second-order RC equivalent circuit model, from the time domain perspective, the time constants of the two RC links should be on different time scales.

[0049] Based on the above analysis process, this embodiment intends to split the traditional parameter identification process into three time scale identification processes based on time scales, namely, the fast identification process corresponding to the ohmic resistance R0 on the first time scale, the RC link representing charge transfer on the second time scale, and the RC link representing charge diffusion on the third time scale, which are hereinafter referred to as the first time scale, the second time scale, and the third time scale respectively.

[0050] The above first frequency range can be understood as the range corresponding to greater than 310 Hz, and the first time scale is the time scale corresponding to 310 Hz. Thus, within the first time scale and the first frequency range, the first resistance parameter R0 corresponding to the first resistance R0 is determined as the parameter to be identified, and then the result of R0 is identified on the first time scale to obtain the change situation of R0 in the first time scale.

[0051] S221. In the second frequency range, determine that the to-be-identified parameters corresponding to the second time scale are the second resistance parameter corresponding to the second resistance in the second resistance unit and the first capacitance parameter corresponding to the first capacitance.

[0052] The above second frequency range can be between 0.2 Hz and several hundred Hz. Specifically, it can be a range greater than or equal to 0.2 Hz and less than 310 Hz. The second time scale is the time scale corresponding to generating 0.2 Hz to 310 Hz. Thus, within the range of the second time scale and the second frequency range, the second resistance parameter R s corresponding to the second resistance and the first capacitance parameter C s corresponding to the first capacitance are determined as the to-be-identified parameters. Furthermore, in the second time scale, the results of R s and C s are separately identified to obtain the change situations of R s and C s in the second time scale.

[0053] S222. In the third frequency range, determine that the to-be-identified parameters corresponding to the third time scale are the third resistance parameter corresponding to the third resistance in the third resistance unit and the second capacitance parameter corresponding to the second capacitance.

[0054] The above third frequency range can be a range less than 0.2 Hz. The third time scale is the time scale corresponding to generating less than 0.2 Hz. Thus, within the range of the third time scale and the third frequency range, the third resistance parameter R p corresponding to the third resistance and the second capacitance parameter C p corresponding to the second capacitance are determined as the to-be-identified parameters. Furthermore, in the third time scale, the results of R p and C p are separately identified to obtain the change situations of R p and C p in the third time scale.

[0055] S230. For any resistance unit, transform the voltage-current relationship into a least-squares expression related to at least one to-be-identified parameter of the resistance unit on the current time scale.

[0056] On a relatively long time scale, the wave presented by the current bias is based on the recursive least-squares algorithm. Based on this, when calculating at least one to-be-identified parameter of the resistance unit corresponding to each time scale in the solution provided by this embodiment, the specific method is to transform the voltage-current relationship obtained in the above step S210 into an expression related to at least one to-be-identified parameter of the current time scale, and further identify the current expression as the form of the least-squares expression, so as to obtain each to-be-identified parameter based on the recursive least-squares method.

[0057] Specifically, the present application provides a preferred embodiment, and the above step S230 can be implemented in the following manner:

[0058] Determine a first expression related to at least one parameter to be identified of the resistance unit according to the voltage-current relationship; perform a Laplace transform on the first expression to obtain a second expression related to at least one parameter to be identified of the resistance unit; perform a bilinear transform on the second expression to obtain a third expression related to at least one parameter to be identified of the resistance unit; convert the third expression into a least squares expression respectively to obtain a least squares expression related to at least one parameter to be identified of the resistance unit.

[0059] The following uses formulas to specifically illustrate the least squares expression related to at least one parameter to be identified of the resistance unit based on the voltage-current relationship at each time scale, as follows:

[0060] First, the purpose of the first time scale is to identify the first resistance parameter corresponding to the first resistance unit in the second-order RC equivalent circuit model. Specifically, the process of converting the voltage-current relationship into the least squares expression related to the parameter to be identified in the first resistance unit on the first time scale is as follows:

[0061] From formula (1), we can obtain

[0062] u oc (t) - u t (t) - u s (t) - u p (t) = i(t)R0 (2)

[0063] Perform a Laplace transform on formula (2), and the corresponding transfer function obtained is:

[0064]

[0065] The above formula (3) is the second expression related to the first resistance parameter R0.

[0066] Perform a bilinear transform on the above formula (3) to transform the transfer function from the complex frequency domain to the frequency domain, and we can obtain:

[0067] G(z -1 ) = R0 (4)

[0068] The above formula (4) is the third expression related to the first resistance parameter R0.

[0069] Convert the above formula (4) into a least squares expression, which is specifically expressed in the following form:

[0070] y(k) = h T (k)θ (5)

[0071] Among them,

[0072] h T (k) = i(k) (6)

[0073] θ = R0 (7)

[0074] The above formula (5) is the least - square expression related to the first resistance parameter R0 in the first resistance unit.

[0075] Second, the purpose of the second time scale is to identify the second resistance parameter and the first capacitance parameter in the second resistance unit of the second - order RC equivalent circuit model. Specifically, the process of transforming the voltage - current relationship into the least - square expression related to the second resistance parameter and the first capacitance parameter on the second time scale is as follows:

[0076] From formula (1), we can get

[0077] u oc (t) - u t (t) - u p (t) = i(t)R0 + u s (t) (8)

[0078] Performing Laplace transform on formula (8), the corresponding transfer function is obtained as:

[0079]

[0080] The above formula (9) is the second expression related to the second resistance parameter R s and the first capacitance parameter C s correspondingly.

[0081] Performing bilinear transform on the above formula (9), let s = 2 / T·[(1 - Z -1 ) / (1 + Z -1 )], where T is the sampling time interval. Transforming the transfer function from the complex - frequency domain to the frequency domain, we can get:

[0082]

[0083] Let,

[0084]

[0085] We can get:

[0086]

[0087] The above formula (11) is the third expression related to the second resistance parameter R s and the first capacitance parameter C s correlated.

[0088] The above formula (11) can be transformed into a least - squares expression, which is specifically expressed in the following form:

[0089]

[0090] Wherein,

[0091] h T (k)=[y(k - 1)i(k)i(k - 1)] T (13)

[0092] θ = [a1a2a3] (14)

[0093] Furthermore, by substituting θ back into formulas (10) and (11) and deriving, the second resistance parameter R s and the first capacitance parameter C s can be obtained, and the calculation formula is

[0094]

[0095] III. The purpose of the third time scale is to identify the third resistance parameter and the second capacitance parameter in the third resistor unit of the third - order RC equivalent circuit model. Specifically, the process of transforming the voltage - current relationship into a least - squares expression related to the third resistance parameter and the second capacitance parameter on the third time scale is as follows:

[0096] From formula (1), we can get

[0097] u oc (t)-u t (t)-u s (t)-i(t)R0 = u p (t) (17)

[0098] Performing Laplace transform on formula (17), the corresponding transfer function is obtained as:

[0099]

[0100] The above formula (18) is the second expression related to the third resistance parameter R p and the second capacitance parameter C p .

[0101] Performing bilinear transform on the above formula (18), the transfer function can be transformed from the complex - frequency domain to the frequency domain, and we get

[0102]

[0103] Let We can obtain:

[0104]

[0105] The above formula (20) is the third expression related to the third resistor parameter R p and the second capacitor parameter C p .

[0106] The above formula (20) can be transformed into a least squares expression, specifically expressed in the following form:

[0107] y(k) = u oc (k) - u t (k) - u s (k) - i(k)R0

[0108] = b1y(k - 1) + b2i(k) + b2i(k - 1) (21) where,

[0109] h T (k) = [y(k - 1)i(k) + i(k - 1)] T (22)

[0110] θ = [b1 b2] (23)

[0111] Furthermore, by substituting θ back into formulas (19) and (20) for derivation, the third resistor parameter R p and the second capacitor parameter C p can be obtained, and the calculation formula is

[0112]

[0113] S231. Calculate the least squares expression of each resistor unit based on the standard least squares recurrence formula to obtain the parameter identification results of each parameter to be identified.

[0114] The above formulas (6) and (7) can be the least squares expressions of the first resistor unit, formulas (13) and (14) can be the least squares expressions of the second resistor unit, and formulas (22) and (23) can be the least squares expressions of the third resistor unit; substitute the least squares expressions of the above resistor units into the standard least squares recurrence formula for iterative calculation of each circuit parameter, and the representation form of the standard least squares recurrence formula is as follows:

[0115]

[0116] where, θ k is the parameter to be calculated; L k is the gain matrix; P k is the covariance matrix; I is the identity matrix.

[0117] For the above gain matrix L k and covariance matrix P k the derivation is as follows:

[0118] The recursive least squares method is based on the least squares principle, and iterates on the model input and output values at each moment to obtain the model parameters. Given the simplicity and practicality of the recursive least squares, in the field of lithium battery parameter identification, for the established mathematical model, it can be arranged into the form of an autoregressive model:

[0119] y(k) = h T (k)θ (27)

[0120] where k is the sampling time, y(k) is the model output vector, h T (k) is the state quantity at the relevant time, and θ is the parameter to be identified in the model.

[0121] For ease of explanation, the autoregressive model is transposed, and a new term is defined as

[0122]

[0123] where represents the estimated value of the parameter to be identified.

[0124] Specifically, in the iterative process of the recursive least squares algorithm, the covariance P is needed to represent the confidence level of the parameter identification result obtained in the current iterative loop, and the covariance P also participates in the iteration. Therefore, at initialization, it is necessary to assign initial values to both the covariance matrix P and the parameter vector θ to be identified, and there is

[0125] P(0) = P0, θ(0) = θ0 (29)

[0126] Furthermore, the parameter to be identified at the current time is updated through the gain matrix L(k) and the new term v(k) at the previous time, and there is

[0127]

[0128] and the calculation formula for the gain matrix L(k) is

[0129] L(k) = P(k - 1)h(k)[1 + h T (k)P(k - 1)h(k)] -1 (31)

[0130] Since the covariance matrix P(k - 1) at the previous time is used in the gain matrix L(k), the covariance matrix P(k) needs to be updated at the end of each iteration step, and there is

[0131] P(k) = P(k - 1) - L(k)h T (k)P(k - 1) (32)

[0132] Based on the above formula, the gain matrix L can be solved and obtained k and the covariance matrix Pk.

[0133] In the solution provided by this application, the first resistance unit corresponds to the first least - squares expressions as the above formula (6) and formula (7), the first factor included in the first least - squares expression is θ; the second resistance unit corresponds to the second least - squares expressions as formula (13) and formula (14), the second factor included in the second least - squares expression is a1, a2, and a3 in formula (15) and formula (16), and the third resistance unit corresponds to the third least - squares expressions as formula (22) and formula (23), and the third factor included in the third least - squares expression is b1 and b2.

[0134] Among them, the first resistance parameter is related to the first factor, see the expression corresponding to formula (7); the second resistance parameter is related to the second factor, see the expression corresponding to formula (15), the first capacitance parameter is related to the second factor, see the expression corresponding to formula (16); the third resistance parameter is related to the third factor, see the expression corresponding to formula (24), and the second capacitance parameter is related to the third factor, see the expression corresponding to formula (25).

[0135] Specifically, the above step S231 can be implemented through the following steps:

[0136] Calculate the least - squares expressions corresponding to each resistance unit based on the standard least - squares recurrence formula, and respectively obtain the iterative results of the first factor, the second factor, and the third factor; determine the first resistance parameter according to the iterative result of the first factor; determine the second resistance parameter and the first capacitance parameter according to the iterative result of the second factor; determine the third resistance parameter and the second capacitance parameter according to the iterative result of the third factor.

[0137] That is, in this embodiment, the least - squares expressions corresponding to each resistance parameter and the gain matrix L k (corresponding to formula (31)) and the covariance matrix P k (corresponding to formula (32)) are substituted into formula (26) to calculate θ k , and further substitute the result of θ k into the formula according to formula (7) to calculate the first resistance parameter R0, substitute the result of θ k into formula (14) to obtain the iterative results of a1, a2, and a3, and further substitute a1, a2, and a3 into formula (15) and formula (16) respectively, to obtain the second resistance parameter R s and the first capacitance parameter Cs result; Substitute the result of θ k into formula (22) to obtain the iterative results of b1 and b2. Further substitute b1 and b2 into formula (24) and formula (25) respectively to obtain the third resistance parameter R p and the second capacitance parameter C p result.

[0138] It should be noted that the first resistance parameter R0, the second resistance parameter R s , the first capacitance parameter C s , the third resistance parameter R p and the second capacitance parameter C p obtained by the above calculations are the processes of repeated calculations on the corresponding time scales. The identification results of each parameter obtained correspondingly can be continuous values on the corresponding time scales, or can be a preset number of values. The preset number can be understood as calculating 20 corresponding parameter identification results, or 30, or 50, etc. on each time scale. The specific selection of the preset number is not limited here, as long as the obtained number has research significance for the performance evaluation of lithium batteries.

[0139] In another preferred embodiment, the lithium battery parameter identification scheme provided in this embodiment further includes the following operations before performing step S230: determining the power trigger threshold corresponding to each time scale, so as to start the operation of determining and executing at least one parameter to be identified on the next time scale based on the voltage-current relationship when the remaining power of the current battery reaches the corresponding power trigger threshold.

[0140] In this embodiment, the basis for determining the power trigger threshold corresponding to each time scale is that the parameter identification of the first time scale will be carried out simultaneously with the sampling time, and the sampling time is 1 second. The starting conditions for the latter two time scales adopt an adaptive starting method, using the change of the power trigger threshold to reflect the current working condition of the lithium battery, and setting the power trigger threshold as the starting condition, so as to start determining and executing at least one parameter to be identified on the next time scale based on the voltage-current relationship. The identification algorithms of the first and second time scales are coupled through the terminal voltage Us of the RC link of the second time scale; the identification algorithms of the second and third time scales are coupled through the terminal voltage Up of the RC link of the third time scale. The identification algorithm continuously updates and adjusts the equivalent circuit model parameters to make u s , u p tend to the true value, which helps the algorithm to be stable.

[0141] Specifically, determine the power trigger threshold corresponding to each time scale, and use the change amount of SOC reaching the corresponding threshold as the starting condition for the parameter identification of the remaining two RC links. The specific calculation formula is as follows:

[0142]

[0143] Among them, SOC0 is the initial value of SOC, and the initial value of SOC is 1 when the lithium battery is fully charged; C N is the rated capacity of the lithium battery.

[0144] Another preferred embodiment. The lithium battery parameter identification scheme provided in this embodiment, after performing step S231, may further include the following operations: statistically analyzing the parameter identification results of the corresponding parameters to be identified at each time scale, and obtaining the parameter change curves of each parameter to be identified at the corresponding time scale. For the parameter identification results of the parameters to be identified obtained at each time scale, the coordinate curves of the corresponding parameters at the corresponding time scales can be fitted. Optionally, the current parameter change curve can also be a curve related to the change of the parameter in the current time scale and the remaining charge of the battery. The specific fitting method of the parameter change curve is not limited here, which helps to intuitively analyze the change of the corresponding parameters to be identified of the lithium battery at each time scale.

[0145] The lithium battery parameter identification method provided in this embodiment analyzes the multi-time scale effect of the second-order RC equivalent circuit model, thereby determining the first time scale, the second time scale, and the third time scale according to the video characteristics of the second-order RC equivalent circuit model. Then, based on the least squares method, the parameters to be identified corresponding to each resistor unit are determined at each time scale, and then each parameter to be identified is calculated at the corresponding time scale, improving the accuracy of calculating each parameter to be identified orally, so that the obtained lithium battery parameter identification results can better provide a basis for battery performance research.

[0146] Figure 4 is a structural schematic diagram of a lithium battery parameter identification device provided by an embodiment of the present application. This device is applicable to execute the lithium battery parameter identification method provided by an embodiment of the present application. As Figure 4 shown, this device may specifically include: a first determination module 410, a second determination module 420, and a parameter calculation module 430.

[0147] Among them, the first determination module 410 is used to determine the voltage-current relationship in the resistor-capacitor C equivalent circuit model. The RC equivalent circuit model includes at least two resistor units, and one of the resistor units corresponds to at least one parameter to be identified.

[0148] The second determination module 420 is used to determine at least one parameter to be identified of the resistor unit corresponding to each time scale based on the time-frequency characteristics of the RC equivalent circuit model.

[0149] A parameter calculation module 430 is configured to calculate at least one parameter to be identified of a resistance unit corresponding to each time scale based on the voltage-current relationship, and obtain a parameter identification result of each parameter to be identified.

[0150] The lithium battery parameter identification device provided by the embodiment of the present application first determines the voltage-current relationship in the resistance-capacitance (R-C) equivalent circuit model. The R-C equivalent circuit model includes at least two resistance units, and one resistance unit corresponds to at least one parameter to be identified. Then, based on the time-frequency characteristics of the R-C equivalent circuit model, at least one parameter to be identified of the resistance unit corresponding to each time scale is determined. Finally, at least one parameter to be identified of the resistance unit corresponding to each time scale is calculated based on the voltage-current relationship, and a parameter identification result of each parameter to be identified is obtained. By analyzing and calculating the parameters to be identified of each resistance unit by dividing them into corresponding time scales, the parameter identification result of the parameter to be identified corresponding to each time scale can be obtained, which can improve the parameter identification accuracy and achieve the beneficial effect of improving the parameter identification accuracy of the lithium battery.

[0151] In one embodiment, the R-C equivalent circuit model includes a second-order R-C equivalent circuit model. The second-order R-C equivalent circuit model includes a first resistance unit, a second resistance unit, and a third resistance unit. The first resistance unit includes a first resistor. The second resistance unit includes a second resistor and a first capacitor connected in parallel. The third resistance unit includes a third resistor and a second capacitor connected in parallel. The time-frequency characteristics include time scale characteristics and frequency characteristics. The time scale characteristics include a first time scale, a second time scale, and a third time scale. The frequency characteristics include a first frequency range, a second frequency range, and a third frequency range. The first frequency range is higher than the second frequency range, and the second frequency range is higher than the third frequency range.

[0152] The second determination module 420 is specifically configured to, within the first frequency range, determine the parameter to be identified corresponding to the first time scale as the first resistance parameter corresponding to the first resistor in the first resistance unit; within the second frequency range, determine the parameters to be identified corresponding to the second time scale as the second resistance parameter corresponding to the second resistor and the first capacitance parameter corresponding to the first capacitor in the second resistance unit; within the third frequency range, determine the parameters to be identified corresponding to the third time scale as the third resistance parameter corresponding to the third resistor and the second capacitance parameter corresponding to the second capacitor in the third resistance unit.

[0153] In one embodiment, the parameter calculation module 430 includes a parameter conversion unit and a parameter calculation unit.

[0154] Among them, the parameter conversion unit is used to convert the voltage-current relationship into a least-squares expression related to at least one parameter to be identified of the resistance unit on the current time scale for any resistance unit.

[0155] The parameter calculation unit is used to calculate the least-squares expression of each resistance unit based on the standard least-squares recurrence formula to obtain the parameter identification result of each parameter to be identified.

[0156] In one embodiment, the parameter conversion unit is specifically configured to determine a first expression related to at least one parameter to be identified of the resistance unit according to the voltage-current relationship; perform a Laplace transform on the first expression to obtain a second expression related to at least one parameter to be identified of the resistance unit; perform a bilinear transform on the second expression to obtain a third expression related to at least one parameter to be identified of the resistance unit; convert the third expression into a least-squares expression respectively to obtain the least-squares expression related to at least one parameter to be identified of the resistance unit.

[0157] In one embodiment, the first resistance unit corresponds to a first least-squares expression, and the first least-squares expression includes a first factor; the second resistance unit corresponds to a second least-squares expression, and the second least-squares expression includes a second factor. The third resistance unit corresponds to a third least-squares expression, and the third least-squares expression includes a third factor; the first resistance parameter is related to the first factor, the second resistance parameter and the first capacitance parameter are respectively related to the second factor, and the third resistance parameter and the second capacitance parameter are respectively related to the third factor.

[0158] The parameter calculation unit is specifically configured to calculate the least-squares expression corresponding to each resistance unit based on the standard least-squares recurrence formula to obtain the iterative results of the first factor, the second factor, and the second factor respectively; determine the first resistance parameter according to the iterative result of the first factor; determine the second resistance parameter and the first capacitance parameter respectively according to the iterative result of the second factor; determine the third resistance parameter and the second capacitance parameter respectively according to the iterative result of the third factor.

[0159] In one embodiment, the device further includes a threshold determination module.

[0160] Among them, the threshold determination module is used to determine the power trigger threshold corresponding to each time scale, so as to start the operation of determining and executing at least one parameter to be identified on the next time scale based on the voltage-current relationship when the current remaining battery power reaches the corresponding power trigger threshold.

[0161] In one embodiment, the device further includes a result statistics module.

[0162] Among them, the parameter identification results of the parameters to be identified corresponding to each time scale are statistically obtained, and the parameter change curves of each of the parameters to be identified on the corresponding time scale are obtained.

[0163] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the above-mentioned division of each functional module is used as an example for illustration. In practical applications, the above-mentioned functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working processes of the above-described functional modules can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0164] The embodiment of the present application further provides an electronic device, and the electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the lithium battery parameter identification method according to any embodiment of the present application.

[0165] The embodiment of the present application further provides a computer-readable medium, and the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the lithium battery parameter identification method according to any embodiment of the present application when executed.

[0166] Refer to the following Figure 5 , Figure 5 which is a schematic structural diagram of an electronic device for a lithium battery parameter identification method provided by an embodiment of the present application. It shows a schematic structural diagram of a computer system 500 of an electronic device suitable for implementing the embodiment of the present application. Figure 5 The electronic device shown is only an example and should not bring any limitation to the functions and usage scope of the embodiment of the present application.

[0167] As Figure 5 shown, the computer system 500 includes a central processing unit (CPU) 501, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 502 or the program loaded from the storage section 508 into the random access memory (RAM) 503. In the RAM 503, various programs and data required for the operation of the system 500 are also stored. The CPU 501, ROM 502, and RAM 503 are connected to each other through a bus 504. The input / output (I / O) interface 505 is also connected to the bus 504.

[0168] The following components are connected to the I / O interface 505: an input section 506 including a keyboard, a mouse, etc.; an output section 507 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc. and a speaker, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a LAN card, a modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the I / O interface 505 as required. A removable medium 511 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is installed on the drive 510 as required so that a computer program read therefrom is installed into the storage section 508 as required.

[0169] Specifically, according to the embodiments disclosed by the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments disclosed by the present invention include a computer program product which includes a computer program carried on a computer-readable medium, and the computer program includes program codes for performing the methods shown in the flowcharts. In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 509, and / or installed from the removable medium 511. When the computer program is executed by a central processing unit (CPU) 501, the above-described functions defined in the system of the present invention are performed.

[0170] It should be noted that the computer-readable medium shown in the present invention can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium can 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 the present invention, the computer-readable storage medium can be any tangible medium that contains or stores a program, which can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present invention, the computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any appropriate medium, including but not limited to: wireless, wire, and optical cable, etc., or any suitable combination of the above.

[0171] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code, and the above module, program segment, or part of code contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0172] The modules and / or units involved in this embodiment can be implemented in software or in hardware. The described modules and / or units can also be provided in a processor. For example, it can be described as: a processor includes a first determination module, a second determination module, and a parameter calculation module. Among them, the names of these modules do not constitute a limitation to the module itself in some cases.

[0173] As another aspect, the present invention also provides a computer-readable medium, which can be included in the device described in the above embodiment; or it can exist alone without being assembled into the device. The above computer-readable medium carries one or more programs. When the above one or more programs are executed by a device, the device includes: determining the voltage-current relationship in the resistor-capacitor (R-C) equivalent circuit model, where the R-C equivalent circuit model includes at least two resistor units, and one of the resistor units corresponds to at least one parameter to be identified; determining at least one parameter to be identified of the resistor unit corresponding to each time scale based on the time-frequency characteristics of the R-C equivalent circuit model; calculating at least one parameter to be identified of the resistor unit corresponding to each time scale respectively based on the voltage-current relationship, and obtaining the parameter identification result of each parameter to be identified.

[0174] According to the technical solution of this embodiment, by analyzing and calculating the parameters to be identified of each resistor unit by dividing them into corresponding time scales, the parameter identification result of the parameter to be identified corresponding to each time scale can be obtained, which can improve the parameter identification accuracy and achieve the beneficial effect of improving the parameter identification accuracy of lithium batteries.

[0175] The above specific implementation manners do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for identifying lithium battery parameters, characterized in that, Including: Determine the voltage-current relationship in the resistor-capacitor (R-C) equivalent circuit model. The R-C equivalent circuit model includes at least two resistor units, and one of the resistor units corresponds to at least one parameter to be identified. Based on the time-frequency characteristics of the R-C equivalent circuit model, determine at least one parameter to be identified for the resistor unit corresponding to each time scale. Based on the voltage-current relationship, calculate at least one parameter to be identified for the resistor unit corresponding to each time scale, and obtain the parameter identification result for each parameter to be identified. Among them, the R-C equivalent circuit model includes a second-order R-C equivalent circuit model. The second-order R-C equivalent circuit model includes a first resistor unit, a second resistor unit, and a third resistor unit. The first resistor unit includes a first resistor. The second resistor unit includes a second resistor and a first capacitor connected in parallel. The third resistor unit includes a third resistor and a second capacitor connected in parallel. The time-frequency characteristics include time-scale characteristics and frequency characteristics. The time-scale characteristics include a first time scale, a second time scale, and a third time scale. The frequency characteristics include a first frequency interval, a second frequency interval, and a third frequency interval. The first frequency interval is higher than the second frequency interval, and the second frequency interval is higher than the third frequency interval. The step of determining at least one parameter to be identified for the resistor unit corresponding to each time scale based on the time-frequency characteristics of the R-C equivalent circuit model includes: Within the first frequency interval, determine the parameter to be identified corresponding to the first time scale as the first resistor parameter corresponding to the first resistor in the first resistor unit. Within the second frequency interval, determine the parameters to be identified corresponding to the second time scale as the second resistor parameter corresponding to the second resistor and the first capacitor parameter corresponding to the first capacitor in the second resistor unit. Within the third frequency interval, determine the parameters to be identified corresponding to the third time scale as the third resistor parameter corresponding to the third resistor and the second capacitor parameter corresponding to the second capacitor in the third resistor unit.

2. The lithium battery parameter identification method according to claim 1, wherein The step of calculating at least one parameter to be identified for the resistor unit corresponding to each time scale based on the voltage-current relationship and obtaining the parameter identification result for each parameter to be identified includes: For any resistor unit, transform the voltage-current relationship into a least-squares expression related to at least one parameter to be identified for the resistor unit at the current time scale. Based on the standard least-squares recursive formula, calculate the least-squares expression for each resistor unit, and obtain the parameter identification result for each parameter to be identified.

3. The lithium battery parameter identification method according to claim 2, wherein The step of transforming the voltage-current relationship into a least-squares expression related to at least one parameter to be identified for the resistor unit at the current time scale includes: According to the voltage-current relationship, determine a first expression related to at least one parameter to be identified for the resistor unit. Perform a Laplace transform on the first expression to obtain a second expression related to at least one parameter to be identified for the resistor unit. Perform a bilinear transform on the second expression to obtain a third expression related to at least one parameter to be identified for the resistor unit. Convert the third expression into a least - squares expression respectively, and obtain the least - squares expression related to at least one parameter to be identified of the resistance unit.

4. The lithium battery parameter identification method according to claim 2, wherein The first resistance unit corresponds to a first least - squares expression, and the first least - squares expression includes a first factor; the second resistance unit corresponds to a second least - squares expression, and the second least - squares expression includes a second factor; the third resistance unit corresponds to a third least - squares expression, and the third least - squares expression includes a third factor; the first resistance parameter is related to the first factor, the second resistance parameter and the first capacitance parameter are respectively related to the second factor, and the third resistance parameter and the second capacitance parameter are respectively related to the third factor; Calculating the least - squares expression of each resistance unit based on the standard least - squares recursion formula to obtain the parameter identification result of each parameter to be identified, including: Calculating the least - squares expression corresponding to each resistance unit based on the standard least - squares recursion formula, and respectively obtaining the iteration results of the first factor, the second factor, and the third factor; Determine the first resistance parameter according to the iteration result of the first factor; Determine the second resistance parameter and the first capacitance parameter respectively according to the iteration result of the second factor; Determine the third resistance parameter and the second capacitance parameter respectively according to the iteration result of the third factor.

5. The lithium battery parameter identification method according to claim 1, wherein Before calculating at least one parameter to be identified of the resistance unit corresponding to each time scale based on the voltage - current relationship and obtaining the parameter identification result of each parameter to be identified, it further includes: Determine the power trigger threshold corresponding to each time scale, so as to start the operation of determining and executing the calculation of at least one parameter to be identified on the next time scale based on the voltage - current relationship when the remaining power of the current battery reaches the corresponding power trigger threshold.

6. The lithium battery parameter identification method according to claim 1, characterized in that, After calculating at least one parameter to be identified of the resistance unit corresponding to each time scale based on the voltage - current relationship and obtaining the parameter identification result of each parameter to be identified, it further includes: Statistically analyze the parameter identification results of the parameters to be identified corresponding to each time scale, and obtain the parameter change curve of each parameter to be identified on the corresponding time scale.

7. A lithium battery parameter identification device, characterized in that, For implementing the lithium - battery parameter identification method described in claim 1, the device includes: A first determination module, configured to determine the voltage - current relationship in the resistance - capacitance (R - C) equivalent circuit model, where the R - C equivalent circuit model includes at least two resistance units, and one resistance unit corresponds to at least one parameter to be identified; A second determination module, configured to determine at least one parameter to be identified of the resistance unit corresponding to each time scale based on the time - frequency characteristics of the R - C equivalent circuit model; A parameter calculation module, configured to calculate at least one parameter to be identified of the resistance unit corresponding to each time scale based on the voltage - current relationship, and obtain the parameter identification result of each parameter to be identified.

8. An electronic device, characterized in that, The electronic device includes: At least one processor; and a memory communicatively connected to the at least one processor; Wherein, the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the lithium battery parameter identification method according to any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the lithium battery parameter identification method according to any one of claims 1-6.

Images