Power battery parameter full life cycle prediction method and device

Abstract

The present invention discloses a method and device for predicting the parameters of a power battery throughout its life cycle. The method comprises: establishing a power battery model of kinetic parameters and charge and discharge parameters based on electrode parameters of the power battery under different life cycles; obtaining kinetic parameters of the power battery under different life cycles; and predicting the parameters of the power battery throughout its life cycle according to the kinetic parameters and the power battery model. When predicting the parameters of the power battery throughout its life cycle, the electrode parameters of the power battery are adjusted in real time according to the life cycle of the power battery, so that the error between the kinetic parameters of the power battery throughout its life cycle and the actual kinetic parameters of the power battery is relatively small. By predicting the parameters of the power battery throughout its life cycle based on the kinetic parameters of the power battery throughout its life cycle, not only can the prediction accuracy of the parameters of the power battery throughout its life cycle be improved, but also the prediction of the parameters of the power battery throughout its life cycle under different working conditions can be achieved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of battery design, and in particular to a method and device for predicting power battery parameters throughout their life cycle. Background Art

[0002] With the development of electric vehicles, passenger car users are paying more attention to the power performance requirements and fast charging function requirements of electric vehicle batteries, in order to meet the charging rate requirements of passenger car users for batteries, while ensuring the driving acceleration capability of electric vehicles. During the use of batteries, the internal resistance of the batteries will gradually increase, causing the discharge voltage and discharge power of the batteries to decrease under the same discharge current conditions, thereby affecting the power performance of the batteries. Moreover, when the charging rate of the batteries is too fast, lithium deposition is prone to occur, thereby reducing the electrical performance and safety of the batteries.

[0003] When designing a battery cell, it is necessary to consider the effect of the change in internal resistance on the power performance of the battery cell, and at this time, it is necessary to predict the internal resistance of the battery cell. In the prior art, when predicting the internal resistance, the semi-empirical function method or the electrochemical mechanism model method can be used to predict the internal resistance of the battery cell. When the semi-empirical function method is used to predict the internal resistance of the battery cell, it is necessary to fit the measured value of the internal resistance change in the early stage of the battery cell cycle, calculate the undetermined parameters in the semi-empirical function, and determine the semi-empirical function. Then the semi-empirical function is used to predict the internal resistance of the battery cell in the later stage of the cycle. The semi-empirical function method is only applicable to the case where the measured internal resistance data in the early stage of the cycle has a good regularity, and the predicted internal resistance error in the later stage of the cycle is relatively large. When the electrochemical mechanism model method is used to predict the internal resistance of the battery cell, when the battery cell is a lithium battery, the electrochemical mechanism model can be a lithium-ion battery physical model, which is used to simulate the entire battery structure. However, the electrochemical mechanism model requires a threshold battery capacity, and it is necessary to set the current operating condition boundary to calculate the internal resistance of the battery cell, so that the electrochemical mechanism model method is mostly applicable to the prediction of internal resistance within the initial life cycle of the battery.

[0004] In addition, in the prior art, there are many methods for predicting or testing the lithium deposition window of battery cells, such as voltage relaxation, three-electrode testing, or calculating the negative electrode potential using electrochemical mechanism models. However, most of these methods are for battery cells in the early stages of cycling. In actual use, battery cells continue to age, such as capacity reduction, internal resistance increase, etc. At this time, the lithium deposition phenomenon determined by the prediction or testing method for the lithium deposition window of the battery cell will be different from the actual lithium deposition phenomenon of the battery cell, reducing the accuracy of the battery cell prediction. Summary of the invention

[0005] The present invention provides a method and device for predicting the full life cycle of power battery parameters, so as to improve the accuracy of the prediction of the weighted life cycle of power battery parameters.

[0006] In a first aspect, an embodiment of the present invention provides a method for predicting power battery parameters throughout their life cycle, comprising:

[0007] A power battery model with kinetic parameters and charge and discharge parameters is established based on electrode parameters under different life cycles of the power battery; the charge and discharge parameters include charge and discharge voltage and / or electrode potential;

[0008] Obtaining kinetic parameters of the power battery under different life cycles;

[0009] The full life cycle parameters of the power battery are predicted according to the kinetic parameters and the power battery model.

[0010] Optionally, when the charge and discharge parameters include charge and discharge voltages, predicting the full life cycle parameters of the power battery according to the kinetic parameters and the power battery model includes:

[0011] Predicting the kinetic parameters of the power battery over its entire life cycle according to the kinetic parameters;

[0012] Predicting a charge and discharge voltage curve of the power battery over its entire life cycle according to the kinetic parameters of the power battery over its entire life cycle and the power battery model;

[0013] The internal resistance of the power battery over its entire life cycle is predicted based on the charge and discharge voltage curve and the charge and discharge rate.

[0014] Optionally, when the charge and discharge parameters include electrode potential, predicting the full life cycle parameters of the power battery according to the kinetic parameters and the power battery model includes:

[0015] Predicting the kinetic parameters of the power battery over its entire life cycle according to the kinetic parameters;

[0016] Predicting the electrode potential distribution of the power battery over its entire life cycle according to the kinetic parameters of the power battery over its entire life cycle and the power battery model;

[0017] The lithium deposition state of the power battery throughout its life cycle is predicted according to the electrode potential distribution.

[0018] Optionally, predicting the kinetic parameters of the power battery over the entire life cycle according to the kinetic parameters includes:

[0019] Determine a kinetic parameter model of the power battery over its entire life cycle using a linear regression model based on the kinetic parameters;

[0020] The kinetic parameters of the power battery over its entire life cycle are predicted according to the kinetic parameter model.

[0021] Optionally, before predicting the full life cycle parameters of the power battery according to the kinetic parameters and the power battery model, the method further includes:

[0022] Obtaining actual charge and discharge voltages of the power battery under different life cycles;

[0023] The power battery model is verified according to the kinetic parameters and the actual charge and discharge voltage.

[0024] Optionally, before predicting the full life cycle parameters of the power battery according to the kinetic parameters and the power battery model, the method further includes:

[0025] A three-electrode cell is used to obtain the actual electrode potential of the power battery under different life cycles;

[0026] The power battery model is verified according to the kinetic parameters and the actual electrode potential.

[0027] Optionally, when the three-electrode battery cell is used to obtain the actual electrode potential of the power battery in different life cycles, the method further includes:

[0028] Obtaining actual charge and discharge voltages of the power battery under different life cycles;

[0029] The power battery model is further verified according to the actual charge and discharge voltage.

[0030] Optionally, when obtaining the kinetic parameters of the power battery in different life cycles, the method further includes:

[0031] Obtaining the cycle capacity of the power battery under different life cycles;

[0032] When verifying the power battery model, it also includes:

[0033] The power battery model is further verified based on the cycle capacity.

[0034] Optionally, after verifying the power battery model, the method further includes:

[0035] If the accuracy of the power battery model is less than a preset accuracy, an influence factor of the power battery model is adjusted.

[0036] In a second aspect, an embodiment of the present invention further provides a device for predicting power battery parameters throughout the life cycle, including:

[0037] A model building module, used to build a power battery model of kinetic parameters and charge and discharge parameters based on electrode parameters under different life cycles of the power battery; the charge and discharge parameters include charge and discharge voltage and / or electrode potential;

[0038] An acquisition module, used to acquire kinetic parameters of the power battery under different life cycles;

[0039] A prediction module is used to predict the full life cycle parameters of the power battery according to the kinetic parameters and the power battery model.

[0040] The technical solution of the embodiment of the present invention is to establish a power battery model of kinetic parameters and charge and discharge parameters based on the electrode parameters of the power battery under different life cycles; then obtain the kinetic parameters of the power battery under different life cycles; finally predict the kinetic parameters of the power battery under the full life cycle according to the kinetic parameters, and then use the kinetic parameters of the power battery under the full life cycle for the power battery model, so that the power battery model predicts the full life cycle parameters of the power battery according to the kinetic parameters under the full life cycle of the power battery. The kinetic parameters correspond to the electrode parameters. When predicting the full life cycle parameters of the power battery, the electrode parameters of the power battery are adjusted in real time according to the life cycle of the power battery, so that the error between the kinetic parameters of the power battery under the full life cycle and the actual kinetic parameters of the power battery is relatively small. By predicting the full life cycle parameters of the power battery through the kinetic parameters of the power battery under the full life cycle, not only can the prediction of the full life cycle parameters of the power battery be realized, and the prediction accuracy of the full life cycle parameters of the power battery be improved, but also the prediction of the full life cycle parameters of the power battery under different working conditions can be realized, and the scope of application of the full life cycle prediction method of the power battery parameters is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A flow chart of a method for predicting the full life cycle of power battery parameters provided by an embodiment of the present invention;

[0042] Figure 2 A flowchart of another method for predicting the full life cycle of power battery parameters provided by an embodiment of the present invention;

[0043] Figure 3 A flowchart of another method for predicting the full life cycle of power battery parameters provided by an embodiment of the present invention;

[0044] Figure 4 A schematic diagram of the structure of a power battery parameter full life cycle prediction device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0046] Figure 1 The present invention provides a flow chart of a method for predicting the parameters of a power battery throughout its life cycle. The present invention is applicable to the case where the parameters of a power battery change in real time at different stages of its life cycle. The method can be performed by a device for predicting the parameters of a power battery throughout its life cycle, and specifically includes the following steps:

[0047] S110, establishing a power battery model of kinetic parameters and charge and discharge parameters based on electrode parameters under different life cycles of the power battery; the charge and discharge parameters include charge and discharge voltage and / or electrode potential;

[0048] Among them, the life cycle of a power battery is the number of charge and discharge cycles that the power battery can withstand before the capacity of the power battery drops to a specified value under certain charge and discharge conditions. Different life cycles of power batteries can be characterized by different charge and discharge cycles of the power battery. During the use of the power battery, the kinetic performance of the power battery decreases as the number of charge and discharge cycles increases, so that the electrode parameters of the power battery are different at different life cycles. Among them, the electrode parameters of the power battery may include the positive electrode parameters, negative electrode parameters, diaphragm parameters and electrolyte parameters of the battery. The kinetic performance of the power battery can be characterized by kinetic parameters. For example, kinetic parameters may include diffusion coefficient, conductivity, equilibrium potential, exchange current density and entropy thermal coefficient, etc.

[0049] When establishing a power battery model, the electrode parameters of the battery can be determined based on the life cycle of the power battery, and based on the Newman theoretical model of battery simulation widely used in the industry, combined with the battery's cycle capacity attenuation mechanism, a power battery model of kinetic parameters and charge and discharge parameters can be established. The power battery model can be a one-dimensional model, so that the migration of ions in the battery in the positive and negative electrodes and diaphragms of the battery can be characterized from a one-dimensional perspective. In addition, when the charge and discharge parameters include the charge and discharge voltage, the power battery model can be a power battery model with kinetic parameters about the charge and discharge voltage. When the charge and discharge parameters include the electrode potential, the power battery model can be a power battery model with kinetic parameters about the electrode potential. When the charge and discharge parameters include the charge and discharge voltage and the electrode potential, the power battery model can be a power battery model with kinetic parameters about the charge and discharge voltage and the electrode potential.

[0050] S120, obtaining kinetic parameters of the power battery under different life cycles;

[0051] Among them, when obtaining the kinetic parameters of the power battery under different life cycles, the materials of the electrodes and electrolytes under different life cycles can be determined in combination with the material system of the power battery to be predicted, and the button batteries commonly used in the industry can be made, and the actual kinetic test parameters of the button batteries can be obtained by testing the button batteries as the kinetic parameters of the power battery under different life cycles. Among them, the life cycle of the power battery can include an initial life cycle and a final life cycle, the initial life cycle is a period when the number of charge and discharge times of the power battery is relatively small, and the final life cycle is a period when the number of charge and discharge times of the power battery is relatively large. When obtaining the kinetic parameters of the power battery under different life cycles, the different life cycles can be the periods corresponding to different charge and discharge times of the power battery in the initial life cycle of the power battery. Exemplarily, when the number of charge and discharge times of the power battery in the life cycle is 1500 times, and the initial life cycle is a period when the number of charge and discharge times of the power battery is less than 750 times, then the different life cycles of the power battery can correspond to the life cycles corresponding to any number of charge and discharge times from 1 to 750 times.

[0052] It should be noted that when obtaining the kinetic parameters of the power battery in different life cycles, it is necessary to set the charge and discharge rate of the power battery to determine the kinetic parameters of the power battery in different life cycles under different operating conditions. The different operating conditions may include different charge and discharge rates of the power battery.

[0053] S130. Predicting full life cycle parameters of the power battery according to the kinetic parameters and the power battery model.

[0054] Among them, after obtaining the kinetic parameters of the power battery at different life cycles, the kinetic parameters of the power battery at the full life cycle can be predicted based on the kinetic parameters, and then the kinetic parameters of the power battery at the full life cycle can be used in the power battery model, so that the power battery model predicts the full life cycle parameters of the power battery based on the kinetic parameters at the full life cycle of the power battery. The kinetic parameters correspond to the electrode parameters. When predicting the full life cycle parameters of the power battery, the electrode parameters of the power battery are adjusted in real time according to the life cycle of the power battery, so that the error between the kinetic parameters of the power battery at the full life cycle and the actual kinetic parameters of the power battery is relatively small. Predicting the full life cycle parameters of the power battery by using the kinetic parameters at the full life cycle of the power battery can not only realize the prediction of the full life cycle parameters of the power battery and improve the prediction accuracy of the full life cycle parameters of the power battery, but also realize the prediction of the full life cycle parameters of the power battery under different working conditions, which increases the scope of application of the full life cycle prediction method of the power battery parameters.

[0055] The technical solution of this embodiment is to establish a power battery model of kinetic parameters and charge and discharge parameters based on the electrode parameters of the power battery under different life cycles; then obtain the kinetic parameters of the power battery under different life cycles; finally predict the kinetic parameters of the power battery under the full life cycle according to the kinetic parameters, and then use the kinetic parameters of the power battery under the full life cycle for the power battery model, so that the power battery model predicts the full life cycle parameters of the power battery according to the kinetic parameters under the full life cycle of the power battery. The kinetic parameters correspond to the electrode parameters. When predicting the full life cycle parameters of the power battery, the electrode parameters of the power battery are adjusted in real time according to the life cycle of the power battery, so that the error between the kinetic parameters of the power battery under the full life cycle and the actual kinetic parameters of the power battery is relatively small. By predicting the full life cycle parameters of the power battery through the kinetic parameters of the power battery under the full life cycle, not only can the prediction of the full life cycle parameters of the power battery be realized, and the prediction accuracy of the full life cycle parameters of the power battery be improved, but also the prediction of the full life cycle parameters of the power battery under different working conditions can be realized, and the scope of application of the full life cycle prediction method of the power battery parameters is increased.

[0056] Figure 2 This is a flow chart of another method for predicting the full life cycle of power battery parameters provided by an embodiment of the present invention. Based on the above technical solution, when the charge and discharge parameters include the charge and discharge voltage, S130 can be refined. Figure 2 As shown, the method includes:

[0057] S210, establishing a power battery model of kinetic parameters and charge and discharge parameters based on electrode parameters under different life cycles of the power battery; the charge and discharge parameters include charge and discharge voltage and / or electrode potential;

[0058] S220, obtaining kinetic parameters of the power battery under different life cycles;

[0059] S230, predicting the kinetic parameters of the power battery over its entire life cycle according to the kinetic parameters;

[0060] Among them, after obtaining the kinetic parameters of the power battery in different life cycles, the kinetic parameters of the power battery in the entire life cycle can be predicted based on the kinetic parameters, and a data matrix of the kinetic parameters in the entire life cycle of the power battery can be constructed, that is, a data matrix composed of the kinetic parameters corresponding to the power battery in different life cycles.

[0061] S240, predicting a charge and discharge voltage curve of the power battery over its entire life cycle according to the kinetic parameters of the power battery over its entire life cycle and a power battery model;

[0062] Among them, when the charge and discharge parameters include the charge and discharge voltage, the power battery model is a model of the kinetic parameters with respect to the charge and discharge voltage. When predicting the full life cycle parameters of the power battery based on the kinetic parameters and the power battery model, the parameter output by the power battery model is the charge and discharge voltage. After determining the kinetic parameters of the power battery over its full life cycle, the kinetic parameters of the power battery over its full life cycle can be input into the power battery model, so that the power battery model can predict the charge and discharge voltage of the power battery over its full life cycle and form a charge and discharge voltage curve for the power battery over its full life cycle.

[0063] S250: predicting the internal resistance of the power battery over its entire life cycle according to the charge and discharge voltage curve and the charge and discharge rate.

[0064] Among them, the charge and discharge rate is the charge and discharge current when the power battery is charged and discharged. After determining the charge and discharge voltage curve corresponding to the power battery's full life cycle, the internal resistance of the power battery is determined according to the charge and discharge rate corresponding to the kinetic parameters and the charge and discharge voltage curve, so that the internal resistance of the power battery's full life cycle can be predicted according to the charge and discharge voltage curve and the charge and discharge rate. The charge and discharge voltage curve is determined by the prediction of the kinetic parameters under the power battery's full life cycle, so the accuracy of the charge and discharge voltage curve under the power battery's full life cycle can be improved. Then, the internal resistance of the power battery's full life cycle is predicted by the charge and discharge voltage curve and the charge and discharge rate, which can improve the prediction accuracy of the internal resistance of the power battery's full life cycle, and at the same time, the prediction of the internal resistance of the power battery's full life cycle under different working conditions can be achieved, which increases the scope of application of the power battery parameter full life cycle prediction method.

[0065] Based on the above technical solutions, the kinetic parameters of the power battery in the whole life cycle are predicted according to the kinetic parameters, including:

[0066] Based on the kinetic parameters, a linear regression model is used to determine the kinetic parameter model of the power battery over its entire life cycle;

[0067] Among them, after obtaining the kinetic parameters of the power battery under different life cycles, a machine learning linear regression model can be used to construct a mathematical fitting model through the mathematical change law of the kinetic parameters under different life cycles of the power battery. Then, the fitting model is trained with the obtained kinetic parameters to determine the model of kinetic parameters and life cycle, and the model is used as the kinetic parameter model of the power battery under the whole life cycle.

[0068] The kinetic parameters of the power battery throughout its life cycle are predicted based on the kinetic parameter model.

[0069] Among them, after the kinetic parameter model is determined, the kinetic parameters of the power battery over its entire life cycle can be predicted based on the kinetic parameter model, and different life cycles correspond to different kinetic parameters.

[0070] On the basis of the above technical solutions, before predicting the full life cycle parameters of the power battery according to the kinetic parameters and the power battery model, it also includes:

[0071] Obtain the actual charge and discharge voltage of the power battery under different life cycles;

[0072] When obtaining the kinetic parameters of the power battery under different life cycles, the actual charge and discharge voltage of the power battery under different life cycles can be obtained at the same time. Specifically, after determining the materials of the electrodes and electrolytes under different life cycles and making button batteries commonly used in the industry, when testing the button batteries, the actual kinetic test parameters of the button batteries and the actual charge and discharge voltage at a certain charge and discharge rate can be obtained at the same time.

[0073] Verify the power battery model based on kinetic parameters and actual charge and discharge voltages.

[0074] Among them, after obtaining the kinetic parameters and actual charge and discharge voltage of the power battery under different life cycles, the kinetic parameters under a life cycle can be input into the power battery model to obtain the charge and discharge voltage output by the power battery model under the life cycle, and the charge and discharge voltage is a simulated value of the charge and discharge voltage of the actual power battery simulated by the power battery model under the life cycle. Then, under the same life cycle, the difference between the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model is compared. When the difference is less than or equal to the preset value of the charge and discharge voltage, it is determined that the accuracy of the power battery model is greater than or equal to the preset accuracy, and the accuracy requirements of the power battery model are met. Among them, the preset accuracy corresponds to the preset value of the charge and discharge voltage, and the preset value of the charge and discharge voltage can be determined according to the accuracy requirements of the power battery model. The higher the accuracy requirements of the power battery model, the smaller the preset value of the charge and discharge voltage, and the higher the preset accuracy.

[0075] On the basis of the above technical solution, after verifying the power battery model, it also includes:

[0076] If the accuracy of the power battery model is less than the preset accuracy, the influence factor of the power battery model is adjusted.

[0077] Among them, when verifying the accuracy of the power battery model through the actual charge and discharge voltage, if the difference between the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model under the same life cycle is greater than the preset value of the charge and discharge voltage, it is considered that the accuracy of the power battery model is less than the preset accuracy. At this time, the influence factor of the power battery model can be adjusted to adjust the accuracy of the power battery model, realize the correction of the power battery model, and thus improve the accuracy of the power battery model. Among them, the influence factor of the power battery model can be a related parameter in the power battery model. After adjusting the influence factor of the power battery model, the comparison process of the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model under the same life cycle can be repeated until the difference between the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model under the same life cycle is less than or equal to the preset value of the charge and discharge voltage, so that the accuracy of the power battery model is greater than or equal to the preset accuracy.

[0078] On the basis of the above technical solutions, when obtaining the kinetic parameters of the power battery under different life cycles, it also includes:

[0079] Obtain the cycle capacity of power batteries under different life cycles;

[0080] When the kinetic parameters of the power battery under different life cycles are obtained, the cycle capacity of the power battery under different life cycles can be obtained at the same time. Specifically, after the materials of the electrodes and electrolytes under different life cycles are determined and button batteries commonly used in the industry are manufactured, when the button batteries are tested, the actual kinetic test parameters of the button batteries and the cycle capacity of the power battery can be obtained at the same time.

[0081] When verifying the power battery model, it also includes:

[0082] The power battery model is further verified based on the cycle capacity.

[0083] Among them, the power battery model has different cycle capacities under different life cycles. When the power battery model is input according to the kinetic parameters, the power battery model can simultaneously output the cycle capacities under different life cycles. The cycle capacities output by the power battery model are simulated values ​​of the cycle capacities of the actual power battery under different life cycles simulated by the power battery model. Then, under the same life cycle, the difference between the actual cycle capacity and the cycle capacity output by the power battery model is compared. When the difference is less than or equal to the preset value of the cycle capacity, and the difference between the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model under the same life cycle is less than or equal to the preset value of the charge and discharge voltage, it is determined that the accuracy of the power battery model is greater than or equal to the preset accuracy, which meets the accuracy requirements of the power battery model, so that the power battery model can be further verified to ensure the accuracy of the power battery model.

[0084] It should be noted that if the accuracy of the power battery model is less than the preset accuracy, the influencing factor of the power battery model can be adjusted, and then the above-mentioned comparison process of the actual cycle capacity and the cycle capacity output by the power battery model under the same life cycle, as well as the comparison process of the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model under the same life cycle are repeated, until the difference between the actual cycle capacity and the cycle capacity output by the power battery model under the same life cycle is less than or equal to the preset value of the cycle capacity, and the difference between the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model under the same life cycle is less than or equal to the preset value of the charge and discharge voltage, thereby ensuring that the accuracy of the power battery model is greater than or equal to the preset accuracy.

[0085] Figure 3 This is a flow chart of another method for predicting the full life cycle of power battery parameters provided by an embodiment of the present invention. Based on the above technical solution, when the charge and discharge parameters include electrode potential, S130 can be refined. Figure 3 As shown, the method includes:

[0086] S310, establishing a power battery model of kinetic parameters and charge and discharge parameters based on electrode parameters under different life cycles of the power battery; the charge and discharge parameters include charge and discharge voltage and / or electrode potential;

[0087] S320, obtaining dynamic parameters of the power battery under different life cycles;

[0088] S330, predicting the kinetic parameters of the power battery over its entire life cycle according to the kinetic parameters;

[0089] Among them, after obtaining the kinetic parameters of the power battery in different life cycles, the kinetic parameters of the power battery in the entire life cycle can be predicted based on the kinetic parameters, and a data matrix of the kinetic parameters in the entire life cycle of the power battery can be constructed, that is, a data matrix composed of the kinetic parameters corresponding to the power battery in different life cycles.

[0090] S340, predicting the electrode potential distribution of the power battery over its entire life cycle according to the kinetic parameters of the power battery over its entire life cycle and the power battery model;

[0091] Among them, when the charge and discharge parameters include electrode potential, the power battery model is a model of kinetic parameters with respect to electrode potential. When predicting the full life cycle parameters of the power battery based on the kinetic parameters and the power battery model, the parameter output by the power battery model is the electrode potential. After determining the kinetic parameters of the power battery under the full life cycle, the kinetic parameters of the power battery under the full life cycle can be input into the power battery model, so that the power battery model can predict the electrode potential of the power battery over the full life cycle. Among them, the electrode potential may include the positive electrode potential or the negative electrode potential. When the electrode potential includes the positive electrode potential, the electrode potential can be used to analyze the positive electrode potential distribution of the power battery. When the electrode potential includes the negative electrode potential, the electrode potential can be used to analyze the negative electrode potential distribution of the power battery. Among them, when the negative electrode potential is less than 0V, the power battery is prone to lithium deposition. When analyzing the lithium deposition state of the power battery, the electrode potential distribution includes the negative electrode potential distribution. In addition, the potential of the electrode may be different at different positions of the electrode. When predicting the electrode potential distribution of a power battery throughout its life cycle for analyzing the lithium deposition state of the power battery, the potentials at different locations of the negative electrode can be predicted based on experience, thereby predicting the lithium deposition state of the power battery more accurately.

[0092] S350. Predicting the lithium deposition state of the power battery throughout its life cycle according to the electrode potential distribution.

[0093] Among them, the electrode potential distribution includes the negative electrode potential distribution. After determining the electrode potential distribution corresponding to the full life cycle of the power battery, it can be directly determined whether the negative electrode potential is greater than 0V according to the electrode potential distribution. When the negative electrode potential distribution of the power battery throughout its life cycle is greater than 0V, it is determined that no lithium deposition state occurs during the power battery throughout its life cycle. When the negative electrode potential distribution is less than 0V at a certain stage in the full life cycle of the power battery, it is determined that the lithium deposition state occurs during the life cycle, and the charge and discharge rate of the power battery is too fast. At this time, the charge and discharge rate of the power battery can be reduced, thereby improving the lithium deposition state of the power battery, thereby improving the electrical performance and safety of the power battery. The electrode potential distribution is determined by the prediction of the kinetic parameters under the full life cycle of the power battery, so the accuracy of the electrode potential distribution under the full life cycle of the power battery can be improved, and then the prediction accuracy of the lithium deposition state of the power battery throughout its life cycle can be improved. And when the power battery is in the lithium deposition state, the charge and discharge rate is reduced, thereby improving the electrical performance and safety of the power battery.

[0094] It should be noted that when determining the potential distribution of the negative electrode in a certain life cycle of the power battery, the potential distribution of different positions of the negative electrode can be determined at the same time. When the potentials at different positions of the negative electrode are all greater than 0V, it is determined that no lithium deposition occurs during the entire life cycle of the power battery. When at least one of the potentials at different positions of the negative electrode is less than 0V, it is determined that lithium deposition occurs during the life cycle.

[0095] Similarly, the prediction of kinetic parameters of power batteries over their entire life cycle based on kinetic parameters can also include:

[0096] Based on the kinetic parameters, a linear regression model is used to determine the kinetic parameter model of the power battery over its entire life cycle;

[0097] The kinetic parameters of the power battery throughout its life cycle are predicted based on the kinetic parameter model.

[0098] On the basis of the above technical solutions, before predicting the full life cycle parameters of the power battery according to the kinetic parameters and the power battery model, it also includes:

[0099] Use three-electrode cells to obtain the actual electrode potential of power batteries under different life cycles;

[0100] Among them, when obtaining the actual electrode potential of the power battery under different life cycles, the material system of the power battery that needs to be predicted can be combined to determine the materials of the electrodes and electrolytes under different life cycles and make them into three-electrode cells. The three-electrode cell includes a positive electrode, a negative electrode and a reference electrode. A fixed potential is input through the reference electrode, so that the distribution of the positive electrode potential and the negative electrode potential during the charge and discharge process of the power battery can be detected. When the lithium plating state of the power battery is predicted by the electrode potential, when obtaining the actual electrode potential of the power battery under different life cycles, the actual electrode potential includes the actual potential of the negative electrode.

[0101] Validate power cell models based on kinetic parameters and realistic electrode potentials.

[0102] Among them, after obtaining the kinetic parameters and actual electrode potential of the power battery under different life cycles, the kinetic parameters under a life cycle can be input into the power battery model to obtain the electrode potential output by the power battery model under the life cycle, and the electrode potential is the simulated value of the electrode potential of the actual power battery simulated by the power battery model under the life cycle. Then, under the same life cycle, the difference between the actual electrode potential and the electrode potential output by the power battery model is compared. When the difference is less than or equal to the potential preset value, it is determined that the accuracy of the power battery model is greater than or equal to the preset accuracy, meeting the accuracy requirements of the power battery model. Among them, the preset accuracy corresponds to the potential preset value, and the potential preset value can be determined according to the accuracy requirements of the power battery model. The higher the accuracy requirements of the power battery model, the smaller the potential preset value, and the higher the preset accuracy.

[0103] On the basis of the above technical solution, after verifying the power battery model, it also includes:

[0104] If the accuracy of the power battery model is less than the preset accuracy, the influence factor of the power battery model is adjusted.

[0105] Among them, when verifying the accuracy of the power battery model through the actual electrode potential, if the difference between the actual electrode potential and the electrode potential output by the power battery model under the same life cycle is greater than the potential preset value, it is considered that the accuracy of the power battery model is less than the preset accuracy. At this time, the influence factor of the power battery model can be adjusted to adjust the accuracy of the power battery model, realize the correction of the power battery model, and thus improve the accuracy of the power battery model. Among them, the influence factor of the power battery model can be a related parameter in the power battery model. After adjusting the influence factor of the power battery model, the comparison process of the actual electrode potential and the electrode potential output by the power battery model under the same life cycle can be repeated until the difference between the actual electrode potential and the electrode potential output by the power battery model under the same life cycle is less than or equal to the potential preset value, so that the accuracy of the power battery model is greater than or equal to the preset accuracy.

[0106] On the basis of the above technical solutions, when obtaining the kinetic parameters of the power battery under different life cycles, it also includes:

[0107] Obtain the cycle capacity of power batteries under different life cycles;

[0108] When the kinetic parameters of the power battery under different life cycles are obtained, the cycle capacity of the power battery under different life cycles can be obtained at the same time. Specifically, after the materials of the electrodes and electrolytes under different life cycles are determined and button batteries commonly used in the industry are manufactured, when the button batteries are tested, the actual kinetic test parameters of the button batteries and the cycle capacity of the power battery can be obtained at the same time.

[0109] When verifying the power battery model, it also includes:

[0110] The power battery model is further verified based on the cycle capacity.

[0111] Among them, the power battery model has different cycle capacities under different life cycles. When the power battery model is input according to the kinetic parameters, the power battery model can simultaneously output the cycle capacities under different life cycles. The cycle capacities output by the power battery model are simulated values ​​of the cycle capacities of the actual power battery under different life cycles simulated by the power battery model. Then, under the same life cycle, the difference between the actual cycle capacity and the cycle capacity output by the power battery model is compared. When the difference is less than or equal to the preset value of the cycle capacity, and the difference between the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model under the same life cycle is less than or equal to the preset value of the charge and discharge voltage, it is determined that the accuracy of the power battery model is greater than or equal to the preset accuracy, which meets the accuracy requirements of the power battery model, so that the power battery model can be further verified to ensure the accuracy of the power battery model.

[0112] On the basis of the above technical solution, when using a three-electrode cell to obtain the actual electrode potential of the power battery under different life cycles, it also includes:

[0113] Obtain the actual charge and discharge voltage of the power battery under different life cycles;

[0114] When obtaining the kinetic parameters of the power battery under different life cycles, the actual charge and discharge voltage of the power battery under different life cycles can be obtained at the same time. Specifically, after determining the materials of the electrodes and electrolytes under different life cycles and making button batteries commonly used in the industry, when testing the button batteries, the actual kinetic test parameters of the button batteries and the actual charge and discharge voltage at a certain charge and discharge rate can be obtained at the same time.

[0115] The power battery model is further verified based on the actual charge and discharge voltage.

[0116] Among them, after obtaining the kinetic parameters and actual charge and discharge voltage of the power battery under different life cycles, the kinetic parameters under a life cycle can be input into the power battery model to obtain the charge and discharge voltage output by the power battery model under the life cycle, and the charge and discharge voltage is a simulated value of the charge and discharge voltage of the actual power battery simulated by the power battery model under the life cycle. Then, under the same life cycle, the difference between the actual charge and discharge voltage and the charge and discharge voltage output by the power battery model is compared. When the difference is less than or equal to the preset value of the charge and discharge voltage, it is determined that the accuracy of the power battery model is greater than or equal to the preset accuracy, and the accuracy requirements of the power battery model are met. Among them, the preset accuracy corresponds to the preset value of the charge and discharge voltage, and the preset value of the charge and discharge voltage can be determined according to the accuracy requirements of the power battery model. The higher the accuracy requirements of the power battery model, the smaller the preset value of the charge and discharge voltage, and the higher the preset accuracy.

[0117] It should be noted that when verifying the power battery model, at least one of the actual electrode potential, cycle capacity and actual charge and discharge voltage can be used for verification. When at least two of the actual electrode potential, cycle capacity and actual charge and discharge voltage are used to verify the power battery model, the accuracy of each of the actual electrode potential, cycle capacity and actual charge and discharge voltage for verifying the power battery model must be greater than or equal to the preset accuracy to meet the accuracy requirements of the power battery model.

[0118] An embodiment of the present invention also provides a device for predicting power battery parameters throughout their life cycle. Figure 4 A schematic diagram of the structure of a power battery parameter full life cycle prediction device provided by an embodiment of the present invention. Figure 4 As shown, the device comprises:

[0119] The model building module 10 is used to build a power battery model of kinetic parameters and charge and discharge parameters based on electrode parameters under different life cycles of the power battery; the charge and discharge parameters include charge and discharge voltage and / or electrode potential;

[0120] An acquisition module 20 is used to acquire kinetic parameters of the power battery under different life cycles;

[0121] The prediction module 30 is used to predict the full life cycle parameters of the power battery according to the kinetic parameters and the power battery model.

[0122] The technical solution of this embodiment is to establish a power battery model of kinetic parameters and charge and discharge parameters based on the electrode parameters of the power battery under different life cycles through the model building module; then the acquisition module acquires the kinetic parameters of the power battery under different life cycles; finally, the prediction module predicts the kinetic parameters of the power battery under the full life cycle according to the kinetic parameters, and then the kinetic parameters of the power battery under the full life cycle are used in the power battery model, so that the power battery model predicts the full life cycle parameters of the power battery according to the kinetic parameters under the full life cycle of the power battery. The kinetic parameters correspond to the electrode parameters. When predicting the full life cycle parameters of the power battery, the electrode parameters of the power battery are adjusted in real time according to the life cycle of the power battery, so that the error between the kinetic parameters of the power battery under the full life cycle and the actual kinetic parameters of the power battery is relatively small. By predicting the full life cycle parameters of the power battery through the kinetic parameters of the power battery under the full life cycle, not only can the prediction of the full life cycle parameters of the power battery be realized, and the prediction accuracy of the full life cycle parameters of the power battery be improved, but also the prediction of the full life cycle parameters of the power battery under different working conditions can be realized, and the scope of application of the full life cycle prediction method of the power battery parameters is increased.

[0123] On the basis of the above technical solution, when the charge and discharge parameters include the charge and discharge voltage, the prediction module includes:

[0124] A kinetic parameter prediction unit, used to predict the kinetic parameters of the power battery over its entire life cycle based on the kinetic parameters;

[0125] A charge and discharge voltage prediction unit, used to predict the charge and discharge voltage curve of the power battery over its entire life cycle based on the kinetic parameters of the power battery and the power battery model over its entire life cycle;

[0126] The internal resistance prediction unit is used to predict the internal resistance of the power battery throughout its life cycle based on the charge and discharge voltage curve and the charge and discharge rate.

[0127] Based on the above technical solution, the power battery parameter full life cycle prediction device also includes:

[0128] The first acquisition module is used to obtain the actual charge and discharge voltage of the power battery under different life cycles;

[0129] The first verification module is used to verify the power battery model according to the kinetic parameters and the actual charge and discharge voltage.

[0130] Alternatively, when the charge and discharge parameters include electrode potential, the prediction module includes:

[0131] A kinetic parameter prediction unit, used to predict the kinetic parameters of the power battery over its entire life cycle based on the kinetic parameters;

[0132] The electrode potential prediction unit is used to predict the electrode potential distribution of the power battery throughout its life cycle based on the kinetic parameters and power battery model during the power battery’s life cycle;

[0133] The lithium deposition state prediction unit is used to predict the lithium deposition state of the power battery throughout its life cycle based on the electrode potential distribution.

[0134] Based on the above technical solution, the power battery parameter full life cycle prediction device also includes:

[0135] The second acquisition module is used to obtain the actual electrode potential of the power battery under different life cycles by using a three-electrode battery cell;

[0136] The second verification module is used to verify the power battery model based on kinetic parameters and actual electrode potential.

[0137] Based on the above technical solution, the power battery parameter full life cycle prediction device also includes:

[0138] The third acquisition module is used to obtain the actual charge and discharge voltage of the power battery under different life cycles;

[0139] The third verification module is used to further verify the power battery model according to the actual charge and discharge voltage.

[0140] Based on the above technical solutions, the power battery parameter full life cycle prediction device also includes:

[0141] A fourth acquisition module is used to obtain the cycle capacity of the power battery under different life cycles;

[0142] The fourth verification module is used to further verify the power battery model according to the cycle capacity when verifying the power battery model.

[0143] Based on the above technical solutions, the power battery parameter full life cycle prediction device also includes:

[0144] The adjustment module is used to adjust the influence factor of the power battery model if the accuracy of the power battery model is less than a preset accuracy.

[0145] Based on the above technical solutions, the kinetic parameter prediction unit includes:

[0146] A kinetic parameter model determination subunit, used to determine the kinetic parameter model of the power battery over the entire life cycle using a linear regression model based on the kinetic parameters;

[0147] The kinetic parameter prediction subunit is used to predict the kinetic parameters of the power battery throughout its life cycle based on the kinetic parameter model.

[0148] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for predicting power battery parameters throughout the life cycle, characterized in that: include: A power battery model with kinetic parameters and charge and discharge parameters is established based on electrode parameters under different life cycles of the power battery; the charge and discharge parameters include charge and discharge voltage and / or electrode potential; Acquire the kinetic parameters of the power battery under different life cycles; wherein the different life cycles are periods corresponding to different charge and discharge times in the initial life cycle of the power battery; Predicting the kinetic parameters of the power battery in the full life cycle according to the kinetic parameters; wherein the full life cycle of the power battery includes the initial life cycle and the final life cycle; the number of charge and discharge times corresponding to the initial life cycle is less than one half of the number of charge and discharge times corresponding to the full life cycle, and the number of charge and discharge times corresponding to the final life cycle is greater than or equal to one half of the number of charge and discharge times corresponding to the full life cycle; The full life cycle parameters of the power battery are predicted according to the kinetic parameters of the power battery under the full life cycle and the power battery model; wherein the full life cycle parameters of the power battery include the internal resistance and lithium plating state of the power battery.

2. The method for predicting the full life cycle of power battery parameters according to claim 1, characterized in that: When the charge and discharge parameters include the charge and discharge voltage, predicting the full life cycle parameters of the power battery according to the kinetic parameters of the power battery during the full life cycle and the power battery model includes: Predicting a charge and discharge voltage curve of the power battery over its entire life cycle according to the kinetic parameters of the power battery over its entire life cycle and the power battery model; The internal resistance of the power battery over its entire life cycle is predicted based on the charge and discharge voltage curve and the charge and discharge rate.

3. The method for predicting the power battery parameters throughout the life cycle according to claim 1, characterized in that: When the charge and discharge parameters include electrode potential, predicting the full life cycle parameters of the power battery according to the kinetic parameters of the power battery during the full life cycle and the power battery model includes: Predicting the electrode potential distribution of the power battery over its entire life cycle according to the kinetic parameters of the power battery over its entire life cycle and the power battery model; The lithium deposition state of the power battery throughout its life cycle is predicted according to the electrode potential distribution.

4. The method for predicting the power battery parameters throughout the life cycle according to claim 1, characterized in that: Predicting the kinetic parameters of the power battery over its entire life cycle according to the kinetic parameters includes: Determine a kinetic parameter model of the power battery over its entire life cycle using a linear regression model based on the kinetic parameters; The kinetic parameters of the power battery over its entire life cycle are predicted according to the kinetic parameter model.

5. The method for predicting the power battery parameters throughout the life cycle according to claim 2, characterized in that: Before predicting the full life cycle parameters of the power battery according to the kinetic parameters of the power battery during the full life cycle and the power battery model, the method further includes: Obtaining actual charge and discharge voltages of the power battery under different life cycles; The power battery model is verified according to the kinetic parameters and the actual charge and discharge voltage.

6. The method for predicting the power battery parameters throughout the life cycle according to claim 3, characterized in that: Before predicting the full life cycle parameters of the power battery according to the kinetic parameters of the power battery during the full life cycle and the power battery model, the method further includes: A three-electrode cell is used to obtain the actual electrode potential of the power battery under different life cycles; The power battery model is verified according to the kinetic parameters and the actual electrode potential.

7. The method for predicting the power battery parameters throughout the life cycle according to claim 6, characterized in that: When the three-electrode cell is used to obtain the actual electrode potential of the power battery under different life cycles, it also includes: Obtaining actual charge and discharge voltages of the power battery under different life cycles; The power battery model is further verified according to the actual charge and discharge voltage.

8. The method for predicting the power battery parameters throughout the life cycle according to claim 5 or 6, characterized in that: When obtaining the kinetic parameters of the power battery in different life cycles, it also includes: Obtaining the cycle capacity of the power battery under different life cycles; When verifying the power battery model, it also includes: The power battery model is further verified based on the cycle capacity.

9. The method for predicting the full life cycle of power battery parameters according to claim 5 or 6, characterized in that: After verifying the power battery model, it also includes: If the accuracy of the power battery model is less than a preset accuracy, an influence factor of the power battery model is adjusted.

10. A power battery parameter full life cycle prediction device, characterized in that: include: A model building module, used to build a power battery model of kinetic parameters and charge and discharge parameters based on electrode parameters under different life cycles of the power battery; the charge and discharge parameters include charge and discharge voltage and / or electrode potential; An acquisition module, used to acquire the kinetic parameters of the power battery under different life cycles; wherein the different life cycles are periods corresponding to different charge and discharge times in the initial life cycle of the power battery; a kinetic parameter prediction unit, configured to predict the kinetic parameters of the power battery in the full life cycle according to the kinetic parameters; wherein the full life cycle of the power battery includes the initial life cycle and the final life cycle; the number of charge and discharge times corresponding to the initial life cycle is less than one half of the number of charge and discharge times corresponding to the full life cycle, and the number of charge and discharge times corresponding to the final life cycle is greater than or equal to one half of the number of charge and discharge times corresponding to the full life cycle; A prediction module is used to predict the full life cycle parameters of the power battery according to the kinetic parameters of the power battery under the full life cycle and the power battery model; wherein the full life cycle parameters of the power battery include the internal resistance and lithium plating state of the power battery.

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