A lithium battery charging and discharging acceleration method based on lithium battery electrolyte proportioning adjustment

Abstract

The application discloses a lithium battery charging and discharging acceleration method based on lithium battery electrolyte proportioning adjustment, relates to the technical field of battery charging and discharging, and comprises the following steps: establishing an influence model of the proportion of solvent types on the lithium ion diffusion rate, establishing an influence model of the proportion of solvent types on the formation of an electrolyte-electrode interface film, and establishing an influence model of the lithium ion diffusion rate on the charging and discharging speed; calculating a first speed improvement coefficient of the component proportion adjustment of the solvent type with high dielectric constant and the solvent type with low viscosity; calculating a second speed improvement coefficient of the component proportion adjustment of the solvent type with high dielectric constant and the solvent type with low viscosity; and calculating a charging and discharging estimated value of the solvent type proportioning adjustment scheme. Through the establishment of various models and the calculation of the charging and discharging estimated value of the solvent type proportioning adjustment scheme, the charging and discharging prediction speed is obtained, and the required scheme can be screened out for targeted regulation and control.

Description

Technical Field

[0001] This invention relates to the field of battery charging and discharging technology, specifically to a method for accelerating the charging and discharging of lithium batteries based on adjusting the electrolyte ratio. Background Technology

[0002] The electrolyte in a lithium-ion battery, as an indispensable component, plays a crucial role in conducting lithium ions within the battery, profoundly impacting its overall performance and lifespan. Electrolytes are typically formulated from organic solvents, electrolytes, and various additives. The ratio of organic solvents significantly affects the charge and discharge rates of lithium-ion batteries. Electrolytes usually employ a mixture of solvents with high dielectric constants and those with low viscosity. The high dielectric constant solvent helps increase the lithium-ion diffusion rate, thereby improving the charge and discharge speed, while the low viscosity solvent reacts to form an electrolyte-electrode interface film. This interface film prevents reactions unrelated to charge and discharge, thus minimizing the impact on the charge and discharge speed.

[0003] However, existing technologies do not adequately estimate the specific impact of the ratio of high dielectric constant solvents to low viscosity solvents on the charge and discharge speed, making it difficult to determine a precise control scheme when accelerating charge and discharge. Summary of the Invention

[0004] To address the aforementioned technical problems, a method for accelerating the charging and discharging of lithium batteries based on adjusting the electrolyte ratio is provided. This technical solution solves the problems mentioned in the background section.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for accelerating the charging and discharging of lithium batteries based on adjusting the electrolyte ratio, comprising:

[0007] The actual charge and discharge rate of the electrolyte is obtained, and the actual composition of the electrolyte is obtained. The actual composition consists of electrolyte type and the proportion of the first component, high dielectric constant solvent type and the proportion of the second component, low viscosity solvent type and the proportion of the third component. The solvent used in the electrolyte is a mixture of EC, PC, DEC, DMC, EMC or EP.

[0008] To obtain the target charge-discharge rate after improving the charge-discharge of the electrolyte, when adjusting the ratio, only the proportions of solvents with high dielectric constant and solvents with low viscosity are adjusted.

[0009] A model was established to show the influence of the proportion of solvent types on the lithium-ion diffusion rate, the influence of the proportion of solvent types on the formation of the electrolyte-electrode interface film, and the influence of the lithium-ion diffusion rate on the charge-discharge rate. The electrolyte-electrode interface film is used to maintain the stability of the lithium battery.

[0010] Based on the model of the influence of solvent type ratio on lithium-ion diffusion rate, the first rate improvement coefficient for adjusting the composition ratio of solvent types with high dielectric constant and solvent types with low viscosity is calculated.

[0011] Based on the model of the influence of solvent type ratio on electrolyte-electrode interface film formation, the second rate improvement coefficient for adjusting the component ratio of high dielectric constant solvent type and low viscosity solvent type is calculated.

[0012] Develop at least one solvent type and ratio adjustment scheme;

[0013] Based on the model of the influence of lithium-ion diffusion rate on charge and discharge speed, the first speed enhancement coefficient and the second speed enhancement coefficient, the charge and discharge prediction values ​​of the solvent type ratio adjustment scheme are calculated.

[0014] Based on the charge and discharge prediction, a target solvent type ratio adjustment scheme is selected, and the ratio is adjusted according to the parameters in the target solvent type ratio adjustment scheme.

[0015] Preferably, the model for the influence of the proportion of solvent types on the lithium-ion diffusion rate includes the following steps:

[0016] Subtracting the percentage of the first component of each electrolyte type from 1 yields the adjustable percentage.

[0017] Obtain the range of values ​​for the proportion of solvent types, divide the range of values ​​for the proportion of solvent types at equal intervals, and obtain at least one sampling point;

[0018] Under preset conditions, the conditional diffusion rate of lithium ions is obtained. The preset conditions are: the proportion of electrolyte type is equal to the proportion of first component, the proportion of solvent type is the value at the sampling point, and the EC proportion is the adjustable proportion minus the value at the sampling point.

[0019] The values ​​at the sampling points were paired and fitted with the lithium-ion conditional diffusion rate to obtain the first influence fitting function. The first influence fitting function was then paired with the solvent type, where the values ​​at the sampling points were the independent variables and the lithium-ion conditional diffusion rate was the dependent variable.

[0020] Preferably, the model for establishing the influence of the proportion of solvent types on the formation of the electrolyte-electrode interface film includes the following steps:

[0021] Obtain the range of values ​​for the proportion of solvent types, divide the range of values ​​for the proportion of solvent types at equal intervals, and obtain at least one sampling point;

[0022] Under preset conditions, the permeability of the electrolyte-electrode interface membrane is obtained. The preset conditions are: the proportion of electrolyte types is equal to the proportion of the first component, the proportion of solvent types is the value at the sampling point, and the EC proportion is the adjustable proportion minus the value at the sampling point.

[0023] The values ​​at the sampling points were paired and fitted with the permeability of the electrolyte-electrode interface membrane to obtain the second influence fitting function. The second influence fitting function was then paired with the solvent type, where the values ​​at the sampling points were the independent variables and the permeability of the electrolyte-electrode interface membrane was the dependent variable.

[0024] Preferably, the establishment of the model for the influence of lithium-ion diffusion rate on charge / discharge rate includes the following steps:

[0025] Obtain the range of values ​​for the lithium-ion diffusion rate, divide the range of values ​​for the lithium-ion diffusion rate into equal intervals, and obtain at least one sampling point;

[0026] Under the condition that the lithium-ion diffusion rate is equal to the value at the sampling point, the charging and discharging conditions and rates are obtained;

[0027] The values ​​at the sampling points are paired with the charging and discharging conditions and speeds and fitted to obtain the third influence fitting function, where the values ​​at the sampling points are the independent variables and the charging and discharging conditions and speeds are the dependent variables.

[0028] Preferably, the first speed increase coefficient for calculating the component ratio adjustment of solvents with high dielectric constant and solvents with low viscosity includes the following steps:

[0029] Set a baseline ratio, which is any positive number less than the percentage of the second component;

[0030] The difference between the proportion of the second component and the benchmark proportion is used to obtain the proportion of the benchmark downward adjustment. The proportion of the third component is added to the benchmark proportion to obtain the proportion of the benchmark upward adjustment.

[0031] Substituting the proportion of the second component into the first influence fitting function corresponding to the type of solvent with high dielectric constant, the first benchmark value is obtained;

[0032] Substituting the proportion of the third component into the first influence fitting function corresponding to the type of low-viscosity solvent, the second benchmark value is obtained;

[0033] Substituting the baseline reduction ratio into the first influence fitting function corresponding to the solvent type with high dielectric constant, we obtain the first improvement value;

[0034] Substituting the baseline increase ratio into the first influence fitting function corresponding to the low viscosity solvent type, the second increase value is obtained;

[0035] The first speed increase coefficient is calculated using the first speed increase formula.

[0036] The formula for increasing the first speed is as follows:

[0037]

[0038] Where A is the first speed increase coefficient, b is the percentage of the base reduction, B is the first increase value, c is the percentage of the base increase, C is the second increase value, d is the percentage of the second component, D is the first base value, e is the percentage of the third component, and E is the second base value.

[0039] Preferably, the calculation of the second speed enhancement coefficient for adjusting the component ratio of solvents with high dielectric constant and solvents with low viscosity includes the following steps:

[0040] Substituting the proportion of the second component into the second influence fitting function corresponding to the solvent type with high dielectric constant, the first sample value is obtained;

[0041] Substituting the proportion of the third component into the second influence fitting function corresponding to the type of low-viscosity solvent, the second sample value is obtained;

[0042] Substituting the percentage of baseline reduction into the second influence fitting function corresponding to the solvent type with high dielectric constant, we obtain the first control value;

[0043] Substituting the baseline adjustment ratio into the second influence fitting function corresponding to the low viscosity solvent type, the second adjustment value is obtained;

[0044] The second speed increase coefficient is calculated using the second speed control formula.

[0045] The second speed control formula is as follows:

[0046]

[0047] Where F is the second speed increase coefficient, g is the percentage of the baseline reduction, G is the first control value, h is the percentage of the baseline increase, H is the second control value, i is the percentage of the second component, I is the first sample value, j is the percentage of the third component, and J is the second sample value.

[0048] Preferably, the process of forming at least one solvent type ratio adjustment scheme includes the following steps:

[0049] Using the adjustable proportion and 0 as endpoints, a controllable interval is formed, and at least one identification point is uniformly selected within the controllable interval.

[0050] The difference between the adjustable proportion and the value at the recognition point is used to obtain the recognition symmetry value;

[0051] A solvent type ratio adjustment scheme is formed. In the solvent type ratio adjustment scheme, the value at the identification point is used as the proportion of solvent types with high dielectric constant, and the identification symmetry value is used as the proportion of solvent types with low viscosity.

[0052] Preferably, the calculation of the charge / discharge estimate for the solvent type ratio adjustment scheme includes the following steps:

[0053] The proportion adjustment value is obtained by subtracting the proportion of the second component from the proportion of the solvent with high dielectric constant in the solvent type ratio adjustment scheme;

[0054] Substituting the actual charge and discharge speeds into the third influence fitting function, the actual lithium-ion diffusion rate is obtained by inverse solution.

[0055] The lithium-ion diffusion prediction rate is calculated using the lithium-ion diffusion prediction formula.

[0056] Substituting the estimated lithium-ion diffusion rate into the third influence fitting function, we obtain the charge-discharge estimate.

[0057] The formula for predicting lithium-ion diffusion is as follows:

[0058]

[0059] Where K is the estimated lithium-ion diffusion rate, L is the actual lithium-ion diffusion rate, p is the percentage adjustment value, and M is the baseline percentage.

[0060] Preferably, the step of selecting the target solvent type and ratio adjustment scheme based on the charge / discharge prediction includes the following steps:

[0061] Select a solvent type and ratio adjustment scheme that is consistent with the expected charge / discharge rate and the target charge / discharge rate as a backup scheme;

[0062] When there are multiple preparatory schemes, the preparatory scheme with the smallest percentage adjustment value is selected as the target solvent type ratio adjustment scheme. When there is only one preparatory scheme, the preparatory scheme is used as the target solvent type ratio adjustment scheme.

[0063] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0064] By establishing models for the influence of solvent type ratio on lithium-ion diffusion rate, the influence of solvent type ratio on electrolyte-electrode interface film formation, and the influence of lithium-ion diffusion rate on charge / discharge rate, and calculating the charge / discharge prediction value of solvent type ratio adjustment scheme, the charge / discharge rate of the solvent type ratio adjustment scheme can be predicted. In the prediction, the lithium-ion diffusion and electrolyte-electrode interface film formation are considered, and the influence of both on the charge / discharge rate is combined to obtain a relatively accurate predicted charge / discharge rate. Based on this, the required scheme can be selected for targeted control. Attached Figure Description

[0065] Figure 1This is a schematic flowchart of the lithium battery charging and discharging acceleration method based on lithium battery electrolyte ratio adjustment according to the present invention.

[0066] Figure 2 This is a schematic diagram of the process for establishing a model of the effect of the proportion of solvent types on the lithium-ion diffusion rate according to the present invention.

[0067] Figure 3 This is a schematic flowchart illustrating the influence of the proportion of different solvent types on the formation of the electrolyte-electrode interface film according to the present invention.

[0068] Figure 4 This is a schematic diagram of the process for establishing a model of the effect of lithium-ion diffusion rate on charge and discharge rate according to the present invention.

[0069] Figure 5 This is a schematic diagram of the process for calculating and adjusting the first speed increase coefficient of solvents with high dielectric constant and solvents with low viscosity according to the present invention.

[0070] Figure 6 This is a schematic diagram of the process for calculating and adjusting the composition ratio of solvents with high dielectric constants and solvents with low viscosity according to the present invention, which is a second speed enhancement coefficient.

[0071] Figure 7 This is a schematic diagram of the process for forming at least one solvent type ratio adjustment scheme according to the present invention;

[0072] Figure 8 This is a schematic diagram of the process for calculating the charge-discharge estimate of the solvent type ratio adjustment scheme according to the present invention.

[0073] Figure 9 This is a schematic diagram of the process of selecting and adjusting the ratio of target solvent types based on charge-discharge prediction values ​​according to the present invention. Detailed Implementation

[0074] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0075] Reference Figure 1 As shown, a method for accelerating the charging and discharging of a lithium battery based on adjusting the electrolyte ratio includes:

[0076] The actual charge and discharge rate of the electrolyte is obtained, and the actual composition of the electrolyte is obtained. The actual composition consists of electrolyte type and the proportion of the first component, high dielectric constant solvent type and the proportion of the second component, low viscosity solvent type and the proportion of the third component. The solvent used in the electrolyte is a mixture of EC, PC, DEC, DMC, EMC or EP.

[0077] To obtain the target charge-discharge rate after improving the charge-discharge of the electrolyte, when adjusting the ratio, only the proportions of solvents with high dielectric constant and solvents with low viscosity are adjusted.

[0078] A model was established to show the influence of the proportion of solvent types on the lithium-ion diffusion rate, the influence of the proportion of solvent types on the formation of the electrolyte-electrode interface film, and the influence of the lithium-ion diffusion rate on the charge-discharge rate. The electrolyte-electrode interface film is used to maintain the stability of the lithium battery.

[0079] Based on the model of the influence of solvent type ratio on lithium-ion diffusion rate, the first rate improvement coefficient for adjusting the composition ratio of solvent types with high dielectric constant and solvent types with low viscosity is calculated.

[0080] Based on the model of the influence of solvent type ratio on electrolyte-electrode interface film formation, the second rate improvement coefficient for adjusting the component ratio of high dielectric constant solvent type and low viscosity solvent type is calculated.

[0081] Develop at least one solvent type and ratio adjustment scheme;

[0082] Based on the model of the influence of lithium-ion diffusion rate on charge and discharge speed, the first speed enhancement coefficient and the second speed enhancement coefficient, the charge and discharge prediction values ​​of the solvent type ratio adjustment scheme are calculated.

[0083] Based on the charge and discharge prediction, a target solvent type ratio adjustment scheme is selected, and the ratio is adjusted according to the parameters in the target solvent type ratio adjustment scheme.

[0084] Solvent type and melting point: The type and melting point of the solvent in the electrolyte have a direct impact on the diffusion rate of lithium ions. Chain and cyclic carbonates and carboxylic esters are commonly used solvents. Their melting point and viscosity directly affect the diffusion rate of lithium ions. The lower the melting point and the lower the viscosity, the higher the self-diffusion coefficient of lithium ions, thereby improving fast charging performance. Therefore, different types of solvents will produce different lithium ion diffusion rates. Thus, a model is established to show the influence of the proportion of solvent types on the lithium ion diffusion rate.

[0085] Solvation energy: High ionic conductivity of electrolyte requires solvent to have high lithium-ion solvation energy, while the formation of inorganic electrolyte-electrode interface film requires low lithium-ion solvation energy. Therefore, when designing electrolyte, a balance needs to be found between the two to achieve high ionic conductivity and stable interface film.

[0086] There needs to be a certain distance and isolation between the positive and negative electrodes of a lithium battery to prevent them from coming into direct contact. This is where a special material like an electrolyte separator comes in.

[0087] Electrolyte-electrode interface membrane is a material with a unique porous structure and chemical properties. It can separate the electrolyte between the positive and negative electrodes, so that the positive and negative electrodes will not directly contact or short-circuit. Because the electrolyte membrane has good barrier properties and chemical corrosion resistance, it can protect the ion transfer and electrochemical reaction between the positive and negative electrodes.

[0088] Therefore, it is necessary to predict the permeability of the electrolyte-electrode interface membrane in order to obtain its influence on the charge and discharge rate. The greater the permeability, the faster the charge and discharge rate.

[0089] Concentration: Increasing the concentration of the electrolyte can significantly improve the self-diffusion coefficient of lithium ions, providing a wider channel for lithium ions and thus accelerating the charging and discharging speed. However, changing the lithium ion concentration of the electrolyte has a significant impact, and the heat generated is difficult to control, making it difficult to guarantee absolute safety. In addition, increasing the lithium ion concentration can also lead to uncontrollable costs. Therefore, in this scheme, only the solvent ratio is adjusted.

[0090] EC, PC, DEC, DMC, EMC, and EP contain solvents with both high dielectric constants and low viscosity, thus they can be used as actual components of the electrolyte.

[0091] Reference Figure 2 As shown, establishing a model for the influence of solvent type ratio on lithium-ion diffusion rate includes the following steps:

[0092] Subtracting the percentage of the first component of each electrolyte type from 1 yields the adjustable percentage.

[0093] Obtain the range of values ​​for the proportion of solvent types, divide the range of values ​​for the proportion of solvent types at equal intervals, and obtain at least one sampling point;

[0094] Under preset conditions, the conditional diffusion rate of lithium ions is obtained. The preset conditions are: the proportion of electrolyte type is equal to the proportion of first component, the proportion of solvent type is the value at the sampling point, and the EC proportion is the adjustable proportion minus the value at the sampling point.

[0095] The values ​​at the sampling points were paired and fitted with the lithium-ion conditional diffusion rate to obtain the first influence fitting function. The first influence fitting function was then paired with the solvent type, where the values ​​at the sampling points were the independent variables and the lithium-ion conditional diffusion rate was the dependent variable.

[0096] Because different types of solvents are used, the lithium-ion diffusion rate will also be different. In order to obtain the effect of the proportion of solvent types on the lithium-ion diffusion rate, it is necessary to control the consistency of the test conditions. In the preset conditions, the proportion of the tested solvent types is adjusted, while the other solvent involved in the mixing is fixed as EC, so the test conditions are consistent. Here, the tested solvent type may also be EC.

[0097] Reference Figure 3 As shown, establishing a model for the influence of solvent type ratio on electrolyte-electrode interface film formation includes the following steps:

[0098] Obtain the range of values ​​for the proportion of solvent types, divide the range of values ​​for the proportion of solvent types at equal intervals, and obtain at least one sampling point;

[0099] Under preset conditions, the permeability of the electrolyte-electrode interface membrane is obtained. The preset conditions are: the proportion of electrolyte types is equal to the proportion of the first component, the proportion of solvent types is the value at the sampling point, and the EC proportion is the adjustable proportion minus the value at the sampling point.

[0100] The values ​​at the sampling points were paired and fitted with the permeability of the electrolyte-electrode interface membrane to obtain the second influence fitting function. The second influence fitting function was then paired with the solvent type, where the values ​​at the sampling points were the independent variables and the permeability of the electrolyte-electrode interface membrane was the dependent variable.

[0101] Because different types of solvents are used, the formation of the electrolyte-electrode interface film will also vary. In order to obtain the effect of the proportion of solvent types on the electrolyte-electrode interface film, it is necessary to control the consistency of the test conditions. In the preset conditions, the proportion of the tested solvent types is adjusted, while the other solvent involved in the mixing is fixed as EC, so the test conditions are consistent. Here, the tested solvent type may also be EC. Thus, the permeability of the electrolyte-electrode interface film can be estimated. On the one hand, the electrolyte-electrode interface film protects the operation of lithium batteries; on the other hand, its permeability also affects the lithium-ion diffusion rate, which in turn affects the charge and discharge speed. Therefore, it is necessary to evaluate the formation of the electrolyte-electrode interface film.

[0102] Reference Figure 4 As shown, establishing a model for the influence of lithium-ion diffusion rate on charge / discharge rate includes the following steps:

[0103] Obtain the range of values ​​for the lithium-ion diffusion rate, divide the range of values ​​for the lithium-ion diffusion rate into equal intervals, and obtain at least one sampling point;

[0104] Under the condition that the lithium-ion diffusion rate is equal to the value at the sampling point, the charging and discharging conditions and rates are obtained;

[0105] The values ​​at the sampling points are paired with the charging and discharging conditions and speeds and fitted to obtain the third influence fitting function, where the values ​​at the sampling points are the independent variables and the charging and discharging conditions and speeds are the dependent variables.

[0106] The lithium-ion diffusion rate is positively correlated with the charge / discharge rate, but the functional relationship between the two may not be a direct proportional function. As the lithium-ion diffusion rate increases further, the charge / discharge rate may not increase significantly. Therefore, in order to predict the functional relationship between the two, the obtained test data is fitted.

[0107] Reference Figure 5 As shown, the first speed increase coefficient for calculating the component ratio adjustment of solvents with high dielectric constant and solvents with low viscosity includes the following steps:

[0108] Set a baseline ratio, which is any positive number less than the percentage of the second component;

[0109] The difference between the proportion of the second component and the benchmark proportion is used to obtain the proportion of the benchmark downward adjustment. The proportion of the third component is added to the benchmark proportion to obtain the proportion of the benchmark upward adjustment.

[0110] Substituting the proportion of the second component into the first influence fitting function corresponding to the type of solvent with high dielectric constant, the first benchmark value is obtained;

[0111] Substituting the proportion of the third component into the first influence fitting function corresponding to the type of low-viscosity solvent, the second benchmark value is obtained;

[0112] Substituting the baseline reduction ratio into the first influence fitting function corresponding to the solvent type with high dielectric constant, we obtain the first improvement value;

[0113] Substituting the baseline increase ratio into the first influence fitting function corresponding to the low viscosity solvent type, the second increase value is obtained;

[0114] The first speed increase coefficient is calculated using the first speed increase formula.

[0115] The formula for increasing the first speed is as follows:

[0116]

[0117] Where A is the first speed increase coefficient, b is the percentage of the base reduction, B is the first increase value, c is the percentage of the base increase, C is the second increase value, d is the percentage of the second component, D is the first base value, e is the percentage of the third component, and E is the second base value.

[0118] There are no special requirements for setting the baseline ratio. Since the change in charge and discharge rates caused by the ratio of high dielectric constant solvents to low viscosity solvents is proportional, a first rate boosting coefficient is applied when the control amplitude is the baseline ratio. Then, to calculate the impact of the control ratio, the product of the ratio of the control ratio to the baseline ratio and the first rate boosting coefficient can be used to estimate the impact of the control ratio. This simplifies the calculation process as there is no need to recalculate the various effects. The second rate boosting coefficient is similar. It corresponds to the baseline ratio. The first rate boosting coefficient corresponds to the effect of solvent type on lithium ion diffusion rate, and the second rate boosting coefficient corresponds to the effect of electrolyte-electrode interface film on lithium ion diffusion rate. Since the permeability of electrolyte-electrode interface film can be used as a weight to multiply with lithium ion diffusion rate, the effective lithium ion diffusion rate under the influence of electrolyte-electrode interface film can be obtained.

[0119] Reference Figure 6 As shown, the calculation of the second speed enhancement coefficient for adjusting the component ratio of solvents with high dielectric constants and solvents with low viscosity includes the following steps:

[0120] Substituting the proportion of the second component into the second influence fitting function corresponding to the solvent type with high dielectric constant, the first sample value is obtained;

[0121] Substituting the proportion of the third component into the second influence fitting function corresponding to the type of low-viscosity solvent, the second sample value is obtained;

[0122] Substituting the percentage of baseline reduction into the second influence fitting function corresponding to the solvent type with high dielectric constant, we obtain the first control value;

[0123] Substituting the baseline adjustment ratio into the second influence fitting function corresponding to the low viscosity solvent type, the second adjustment value is obtained;

[0124] The second speed increase coefficient is calculated using the second speed control formula.

[0125] The second speed control formula is as follows:

[0126]

[0127] Where F is the second speed increase coefficient, g is the percentage of the baseline reduction, G is the first control value, h is the percentage of the baseline increase, H is the second control value, i is the percentage of the second component, I is the first sample value, j is the percentage of the third component, and J is the second sample value.

[0128] Reference Figure 7 As shown, forming at least one solvent type ratio adjustment scheme includes the following steps:

[0129] Using the adjustable proportion and 0 as endpoints, a controllable interval is formed, and at least one identification point is uniformly selected within the controllable interval.

[0130] The difference between the adjustable proportion and the value at the recognition point is used to obtain the recognition symmetry value;

[0131] A solvent type ratio adjustment scheme is formed. In the solvent type ratio adjustment scheme, the value at the identification point is used as the proportion of solvent types with high dielectric constant, and the identification symmetry value is used as the proportion of solvent types with low viscosity.

[0132] Reference Figure 8 As shown, the calculation of the charge / discharge estimate for the solvent type and ratio adjustment scheme includes the following steps:

[0133] The proportion adjustment value is obtained by subtracting the proportion of the second component from the proportion of the solvent with high dielectric constant in the solvent type ratio adjustment scheme;

[0134] Substituting the actual charge and discharge speeds into the third influence fitting function, the actual lithium-ion diffusion rate is obtained by inverse solution.

[0135] The lithium-ion diffusion prediction rate is calculated using the lithium-ion diffusion prediction formula.

[0136] Substituting the estimated lithium-ion diffusion rate into the third influence fitting function, we obtain the charge-discharge estimate.

[0137] The formula for predicting lithium-ion diffusion is as follows:

[0138]

[0139] Where K is the estimated lithium-ion diffusion rate, L is the actual lithium-ion diffusion rate, p is the percentage adjustment value, and M is the baseline percentage.

[0140] The change in the mixing ratio will alter the actual lithium-ion diffusion rate. Based on the third influence fitting function, the corresponding charge / discharge rate can be calculated from the lithium-ion diffusion rate. However, due to the change in the lithium-ion diffusion rate, it is necessary to determine the altered lithium-ion diffusion rate. Since the effects of this adjustment include both the direct influence of the solvent and the indirect influence of the electrolyte-electrode interface film, both must be considered together, requiring the multiplication of coefficients. Therefore, a comprehensive understanding of the impact on the actual lithium-ion diffusion rate can be obtained, leading to a predicted lithium-ion diffusion rate.

[0141] Reference Figure 9 As shown, based on the charge / discharge prediction, the selection of the target solvent type and ratio adjustment scheme includes the following steps:

[0142] Select a solvent type and ratio adjustment scheme that is consistent with the expected charge / discharge rate and the target charge / discharge rate as a backup scheme;

[0143] When there are multiple preparatory schemes, the preparatory scheme with the smallest percentage adjustment value is selected as the target solvent type ratio adjustment scheme. When there is only one preparatory scheme, the preparatory scheme is used as the target solvent type ratio adjustment scheme.

[0144] The purpose of selecting the preliminary scheme with the smallest percentage adjustment value is to control the adjustment range. The larger the adjustment range, the longer it takes. Therefore, in order to improve the efficiency of regulation, the preliminary scheme with the smallest percentage adjustment value is selected as the target solvent type ratio adjustment scheme.

[0145] Furthermore, this solution also proposes a storage medium on which a computer-readable program is stored. When the computer-readable program is invoked, the above-mentioned method for accelerating the charging and discharging of lithium batteries based on the adjustment of the lithium battery electrolyte ratio is executed.

[0146] It is understandable that the storage medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid-state drive (SSD).

[0147] In summary, the advantages of this invention are as follows: by establishing models for the influence of solvent type ratio on lithium-ion diffusion rate, the influence of solvent type ratio on electrolyte-electrode interface film formation, and the influence of lithium-ion diffusion rate on charge / discharge rate, and by calculating the charge / discharge prediction value of the solvent type ratio adjustment scheme, the charge / discharge rate of the solvent type ratio adjustment scheme can be predicted. In the prediction, the lithium-ion diffusion and electrolyte-electrode interface film formation are considered, and their combined influence on the charge / discharge rate is integrated, thereby obtaining a more accurate predicted charge / discharge rate. Based on this, the desired scheme can be selected for targeted control.

[0148] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for accelerating the charging and discharging of lithium batteries based on adjusting the electrolyte ratio, characterized in that, include: The actual charge and discharge rate of the electrolyte is obtained, and the actual composition of the electrolyte is obtained. The actual composition consists of electrolyte type and the proportion of the first component, high dielectric constant solvent type and the proportion of the second component, low viscosity solvent type and the proportion of the third component. The solvent used in the electrolyte is a mixture of EC, PC, DEC, DMC, EMC or EP. To obtain the target charge-discharge rate after improving the charge-discharge of the electrolyte, when adjusting the ratio, only the proportions of solvents with high dielectric constant and solvents with low viscosity are adjusted. A model was established to show the influence of the proportion of solvent types on the lithium-ion diffusion rate, the influence of the proportion of solvent types on the formation of the electrolyte-electrode interface film, and the influence of the lithium-ion diffusion rate on the charge-discharge rate. The electrolyte-electrode interface film is used to maintain the stability of the lithium battery. Based on the model of the influence of solvent type ratio on lithium-ion diffusion rate, the first rate improvement coefficient for adjusting the composition ratio of solvent types with high dielectric constant and solvent types with low viscosity is calculated. Based on the model of the influence of solvent type ratio on electrolyte-electrode interface film formation, the second rate improvement coefficient for adjusting the component ratio of high dielectric constant solvent type and low viscosity solvent type is calculated. Develop at least one solvent type and ratio adjustment scheme; Based on the model of the influence of lithium-ion diffusion rate on charge and discharge speed, the first speed enhancement coefficient and the second speed enhancement coefficient, the charge and discharge prediction values ​​of the solvent type ratio adjustment scheme are calculated. Based on the charge and discharge prediction, a target solvent type ratio adjustment scheme is selected, and the ratio is adjusted according to the parameters in the target solvent type ratio adjustment scheme.

2. The method for accelerating the charging and discharging of a lithium battery based on adjusting the electrolyte ratio according to claim 1, characterized in that, The model for the influence of the proportion of solvent types on the lithium-ion diffusion rate includes the following steps: Subtracting the percentage of the first component of each electrolyte type from 1 yields the adjustable percentage. Obtain the range of values ​​for the proportion of solvent types, divide the range of values ​​for the proportion of solvent types at equal intervals, and obtain at least one sampling point; Under preset conditions, the conditional diffusion rate of lithium ions is obtained. The preset conditions are: the proportion of electrolyte type is equal to the proportion of first component, the proportion of solvent type is the value at the sampling point, and the EC proportion is the adjustable proportion minus the value at the sampling point. The values ​​at the sampling points were paired and fitted with the lithium-ion conditional diffusion rate to obtain the first influence fitting function. The first influence fitting function was then paired with the solvent type, where the values ​​at the sampling points were the independent variables and the lithium-ion conditional diffusion rate was the dependent variable.

3. The method for accelerating the charging and discharging of a lithium battery based on adjusting the electrolyte ratio according to claim 2, characterized in that, The model for the influence of the proportion of different solvent types on the formation of the electrolyte-electrode interface film includes the following steps: Obtain the range of values ​​for the proportion of solvent types, divide the range of values ​​for the proportion of solvent types at equal intervals, and obtain at least one sampling point; Under preset conditions, the permeability of the electrolyte-electrode interface membrane is obtained. The preset conditions are: the proportion of electrolyte types is equal to the proportion of the first component, the proportion of solvent types is the value at the sampling point, and the EC proportion is the adjustable proportion minus the value at the sampling point. The values ​​at the sampling points were paired and fitted with the permeability of the electrolyte-electrode interface membrane to obtain the second influence fitting function. The second influence fitting function was then paired with the solvent type, where the values ​​at the sampling points were the independent variables and the permeability of the electrolyte-electrode interface membrane was the dependent variable.

4. The lithium battery charging and discharging acceleration method based on lithium battery electrolyte ratio adjustment according to claim 3, characterized in that, The model for the influence of lithium-ion diffusion rate on charge / discharge rate includes the following steps: Obtain the range of values ​​for the lithium-ion diffusion rate, divide the range of values ​​for the lithium-ion diffusion rate into equal intervals, and obtain at least one sampling point; Under the condition that the lithium-ion diffusion rate is equal to the value at the sampling point, the charging and discharging conditions and rates are obtained; The values ​​at the sampling points are paired with the charging and discharging conditions and speeds and fitted to obtain the third influence fitting function, where the values ​​at the sampling points are the independent variables and the charging and discharging conditions and speeds are the dependent variables.

5. The method for accelerating the charging and discharging of a lithium battery based on adjusting the electrolyte ratio according to claim 4, characterized in that, The calculation of the first speed enhancement coefficient for adjusting the component ratio of solvents with high dielectric constant and solvents with low viscosity includes the following steps: Set a baseline ratio, which is any positive number less than the percentage of the second component; The difference between the proportion of the second component and the benchmark proportion is used to obtain the proportion of the benchmark downward adjustment. The proportion of the third component is added to the benchmark proportion to obtain the proportion of the benchmark upward adjustment. Substituting the proportion of the second component into the first influence fitting function corresponding to the type of solvent with high dielectric constant, the first benchmark value is obtained; Substituting the proportion of the third component into the first influence fitting function corresponding to the type of low-viscosity solvent, the second benchmark value is obtained; Substituting the baseline reduction ratio into the first influence fitting function corresponding to the solvent type with high dielectric constant, we obtain the first improvement value; Substituting the baseline increase ratio into the first influence fitting function corresponding to the low viscosity solvent type, the second increase value is obtained; The first speed increase coefficient is calculated using the first speed increase formula. The formula for increasing the first speed is as follows: Where A is the first speed increase coefficient, b is the percentage of the base reduction, B is the first increase value, c is the percentage of the base increase, C is the second increase value, d is the percentage of the second component, D is the first base value, e is the percentage of the third component, and E is the second base value.

6. The method for accelerating the charging and discharging of a lithium battery based on adjusting the electrolyte ratio according to claim 5, characterized in that, The calculation of the second speed enhancement coefficient for adjusting the component ratio of solvents with high dielectric constant and solvents with low viscosity includes the following steps: Substituting the proportion of the second component into the second influence fitting function corresponding to the solvent type with high dielectric constant, the first sample value is obtained; Substituting the proportion of the third component into the second influence fitting function corresponding to the type of low-viscosity solvent, the second sample value is obtained; Substituting the percentage of baseline reduction into the second influence fitting function corresponding to the solvent type with high dielectric constant, we obtain the first control value; Substituting the baseline adjustment ratio into the second influence fitting function corresponding to the low viscosity solvent type, the second adjustment value is obtained; The second speed increase coefficient is calculated using the second speed control formula. The second speed control formula is as follows: Where F is the second speed increase coefficient, g is the percentage of the baseline reduction, G is the first control value, h is the percentage of the baseline increase, H is the second control value, i is the percentage of the second component, I is the first sample value, j is the percentage of the third component, and J is the second sample value.

7. The method for accelerating the charging and discharging of a lithium battery based on adjusting the electrolyte ratio according to claim 6, characterized in that, The process of forming at least one solvent type ratio adjustment scheme includes the following steps: Using the adjustable proportion and 0 as endpoints, a controllable interval is formed, and at least one identification point is uniformly selected within the controllable interval. The difference between the adjustable proportion and the value at the recognition point is used to obtain the recognition symmetry value; A solvent type ratio adjustment scheme is formed. In the solvent type ratio adjustment scheme, the value at the identification point is used as the proportion of solvent types with high dielectric constant, and the identification symmetry value is used as the proportion of solvent types with low viscosity.

8. The method for accelerating the charging and discharging of a lithium battery based on adjusting the electrolyte ratio according to claim 7, characterized in that, The calculation of the charge / discharge estimate for the solvent type and ratio adjustment scheme includes the following steps: The proportion adjustment value is obtained by subtracting the proportion of the second component from the proportion of the solvent with high dielectric constant in the solvent type ratio adjustment scheme; Substituting the actual charge and discharge speeds into the third influence fitting function, the actual lithium-ion diffusion rate is obtained by inverse solution. The lithium-ion diffusion prediction rate is calculated using the lithium-ion diffusion prediction formula. Substituting the estimated lithium-ion diffusion rate into the third influence fitting function, we obtain the charge-discharge estimate. The formula for predicting lithium-ion diffusion is as follows: Where K is the estimated lithium-ion diffusion rate, L is the actual lithium-ion diffusion rate, p is the percentage adjustment value, and M is the baseline percentage.

9. The method for accelerating the charging and discharging of a lithium battery based on adjusting the electrolyte ratio according to claim 8, characterized in that, The selection of the target solvent type and ratio adjustment scheme based on charge / discharge prediction includes the following steps: Select a solvent type and ratio adjustment scheme that is consistent with the expected charge / discharge rate and the target charge / discharge rate as a backup scheme; When there are multiple preparatory schemes, the preparatory scheme with the smallest percentage adjustment value is selected as the target solvent type ratio adjustment scheme. When there is only one preparatory scheme, the preparatory scheme is used as the target solvent type ratio adjustment scheme.

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