Method and equipment for estimating service life of battery cell blue film

Abstract

The invention discloses a method and equipment for estimating the service life of a battery cell blue film. The equipment comprises a system for estimating the service life of the battery cell blue film and a computer readable storage medium. The method for estimating the service life of the battery cell blue film comprises the following steps: acquiring an insulation value change trend after the battery cell blue film is in contact with cooling liquid; acquiring test information of the battery cell blue film before failure based on the insulation value change trend; acquiring actual working information of the battery cell blue film; and based on the test information and the actual working information, obtaining the estimated service life of the battery cell blue film after contact with the cooling liquid. By means of the mode, the service life estimation method of the battery cell blue film can rapidly obtain the estimated service life of the battery cell blue film after the battery cell blue film makes contact with the cooling liquid, the test time for obtaining the service life of the battery cell blue film is shortened, and the test cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery cell technology, and specifically to a method and device for estimating the life of a battery cell blue film. The device includes a system for estimating the life of a battery cell blue film and a computer-readable storage medium. Background Art

[0002] The insulation performance of the blue film of the battery cell has an important impact on the safety of the battery. As a key insulating material inside the battery, the main function of the blue film of the battery cell is to provide effective isolation between the battery cells to prevent short circuits caused by contact. This helps prevent possible safety accidents such as battery overheating, fire or explosion. However, external environmental factors, such as high temperature or harmful chemicals, may accelerate the aging of the blue film of the battery cell, thereby reducing its insulation performance. Considering that the battery will face complex working conditions in actual use, such as cracks or pinholes that may appear in the pipes and joints of the liquid cooling system, it may cause the coolant to leak into the battery. In this case, the blue film of the battery cell may be in contact with the coolant for a long time. Therefore, it is crucial to verify the insulation performance of the blue film of the battery cell in contact with the coolant. In this special case, the insulation performance of the blue film of the battery cell determines the insulation performance of the battery, that is, the life of the blue film of the battery cell after contact with the coolant determines the life of the battery as a whole, but obtaining the life of the blue film of the battery cell after contact with the coolant requires a long test time, resulting in a large test cost. Summary of the invention

[0003] In order to solve the above problems, the present application proposes a life prediction method and device for a battery cell blue film to solve the above problems.

[0004] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a method for predicting the life of a battery cell blue film, the method for predicting the life of a battery cell blue film comprising: obtaining the insulation value change trend of the battery cell blue film after contact with coolant; obtaining the test information of the battery cell blue film before failure based on the insulation value change trend; obtaining the actual working information of the battery cell blue film; and obtaining the estimated life of the battery cell blue film after contact with coolant based on the test information and the actual working information.

[0005] Among them, the step of obtaining the insulation value change trend of the battery cell blue film after it contacts the coolant includes: constructing an insulation value measuring device for the battery cell blue film in which the battery cell blue film and the coolant are in contact with each other; using the battery cell blue film insulation value measuring device to measure the insulation value of the battery cell blue film in contact with the coolant to obtain the insulation value change trend.

[0006] Among them, the step of obtaining the test information of the battery cell blue film before failure based on the insulation value change trend includes: determining the failure insulation resistance of the battery cell blue film; obtaining the test information of the battery cell blue film when the insulation value change trend is greater than or equal to the failure insulation resistance.

[0007] Among them, the actual working information includes the actual use temperature and the actual profile voltage, and the test information includes the test operating temperature, the test profile voltage and the test time; the steps of obtaining the estimated life of the battery cell blue film after contact with the coolant based on the test information and the actual working information include: obtaining the temperature acceleration factor of the battery cell blue film based on the actual use temperature and the test operating temperature; obtaining the voltage acceleration factor of the battery cell blue film based on the actual profile voltage and the test profile voltage; obtaining the estimated life based on the temperature acceleration factor, the voltage acceleration factor and the test time.

[0008] Among them, the step of obtaining the temperature acceleration factor of the battery cell blue film based on the actual use temperature and the test condition temperature includes: obtaining the activation energy and Boltzmann constant of the battery cell blue film; inputting the activation energy, Boltzmann constant, actual use temperature and test condition temperature of the battery cell blue film into the Arrhenius acceleration model to obtain the temperature acceleration factor.

[0009] Among them, the step of obtaining the voltage acceleration factor of the blue film of the battery cell based on the actual profile voltage and the test profile voltage includes: obtaining the voltage acceleration constant; inputting the voltage acceleration constant, the actual profile voltage and the test profile voltage into the voltage acceleration model to obtain the voltage acceleration factor.

[0010] Among them, the steps of obtaining the estimated life based on the temperature acceleration factor, the voltage acceleration factor and the test time include: obtaining the ratio of the actual sample of the battery cell blue film to the theoretical sample; obtaining the product of the temperature acceleration factor and the voltage acceleration factor; calculating the product of the test time, the product and the ratio to obtain the estimated life.

[0011] In order to solve the above-mentioned technical problems, another technical solution adopted in the present application is: to provide a life prediction system for a battery cell blue film, the life prediction system for the battery cell blue film comprising an insulation value measuring device and a calculation device, the insulation value measuring device is used to obtain the insulation value change trend of the battery cell blue film after it comes into contact with the coolant; the calculation device is connected to the insulation value measuring device, and is used to obtain the test information of the battery cell blue film before failure based on the insulation value change trend, obtain the actual working information of the battery cell blue film, and obtain the estimated life of the battery cell blue film based on the test information and the actual working information.

[0012] Among them, the insulation value measuring device includes safety analysis equipment, a temperature chamber and a lower box of a battery pack; the lower box of the battery pack is arranged inside the temperature chamber, and a coolant is provided in the accommodating cavity of the lower box of the battery pack. The battery cell to be tested is arranged in the accommodating cavity of the lower box of the battery pack and is partially immersed in the coolant. The safety analysis equipment is respectively connected to the battery cell to be tested and the lower box of the battery pack, and is used to measure the insulation value of the blue film of the battery cell to be tested to obtain the changing trend of the insulation value. The temperature chamber is used to simulate the ambient temperature of the battery cell to be tested in the battery pack.

[0013] In order to solve the above technical problems, another technical solution adopted in the present application is: providing a computer-readable storage medium, which stores program instructions, and the program instructions are executed by a processor to implement any of the above-mentioned methods for estimating the life of the blue film of the battery cell.

[0014] The beneficial effects of the present application are: Different from the prior art, the life estimation method of the battery cell blue film of the present application includes: obtaining the insulation value change trend after the battery cell blue film contacts the coolant; obtaining the test information of the battery cell blue film before failure based on the insulation value change trend; obtaining the actual working information of the battery cell blue film; obtaining the estimated life of the battery cell blue film after contacting the coolant based on the test information and the actual working information. In the above manner, the life estimation method of the battery cell blue film of the present application can quickly obtain the estimated life of the battery cell blue film after contacting the coolant, shorten the test time for obtaining the life of the battery cell blue film, and reduce the test cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0016] Figure 1 It is a flow chart of an embodiment of a method for estimating the life of a battery cell blue film provided by the present application;

[0017] Figure 2 yes Figure 1 Step S101 is a flow chart of an embodiment;

[0018] Figure 3 yes Figure 1 A schematic diagram of a flow chart of an embodiment of step S102;

[0019] Figure 4 yes Figure 1 A flow chart of an embodiment of step S104;

[0020] Figure 5 yes Figure 4 Step S401 is a flowchart of an embodiment;

[0021] Figure 6 yes Figure 4 A flow chart of an embodiment of step S402;

[0022] Figure 7 yes Figure 4 A flowchart of an embodiment of step S403;

[0023] Figure 8It is a structural schematic diagram of an embodiment of a life prediction system for a battery blue film provided by the present application;

[0024] Fig. 9 It is a structural schematic diagram of an embodiment of an insulation value measuring device provided by the present application;

[0025] Fig.10 It is a structural schematic diagram of an embodiment of a computer-readable storage medium provided by the present application. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] The insulation performance of the blue film of the battery cell has an important impact on the safety of the battery. As a key insulating material inside the battery, the main function of the blue film of the battery cell is to provide effective isolation between the battery cells to prevent short circuits caused by contact. This helps prevent possible safety accidents such as battery overheating, fire or explosion. However, external environmental factors, such as high temperature or harmful chemicals, may accelerate the aging of the blue film of the battery cell, thereby reducing its insulation performance. Considering that the battery will face complex working conditions in actual use, such as cracks or pinholes that may appear in the pipes and joints of the liquid cooling system, it may cause the coolant to leak into the battery. In this case, the blue film of the battery cell may be in contact with the coolant for a long time. Therefore, it is crucial to verify the insulation performance of the blue film of the battery cell in contact with the coolant. In this special case, the insulation performance of the blue film of the battery cell determines the insulation performance of the battery, that is, the life of the blue film of the battery cell after contact with the coolant determines the life of the battery as a whole, but obtaining the life of the blue film of the battery cell after contact with the coolant requires a long test time, resulting in a large test cost.

[0028] In order to solve the above problems, this application first proposes a method for estimating the life of a battery cell blue film. Figure 1 , Figure 1 1 is a flow chart of an embodiment of a method for estimating the life of a battery cell blue film provided in this application. Figure 1 As shown, the life estimation method of the battery blue film of this embodiment specifically includes steps S101 to S104:

[0029] Step S101: Obtain the insulation value change trend of the battery cell blue film after it comes into contact with the coolant.

[0030] In this embodiment, the present application needs to obtain the insulation value change trend of the battery cell blue film after it comes into contact with the coolant. To this end, the present application constructs an insulation value measurement device for the battery cell blue film in which the battery cell blue film and the coolant are in contact with each other. The insulation value measurement device can measure the insulation value of the battery cell blue film under different working conditions and different voltage profiles. After the insulation value measurement device is constructed, the present application can use the insulation value measurement device to test the battery cell blue film to be tested, thereby obtaining the insulation value change trend of the battery cell blue film to be tested under a given working condition and a given voltage profile for a period of time.

[0031] Step S102: obtaining test information of the battery cell blue film before failure based on the insulation value variation trend.

[0032] After obtaining the insulation value change trend of the battery cell blue film to be tested under a given working condition and a given voltage profile over a period of time, the test information of the battery cell blue film to be tested before failure can be obtained based on the insulation value change trend, that is, when the insulation value change trend of the battery cell blue film is greater than or equal to the failure insulation resistance of the battery cell blue film, the test working condition temperature, test profile voltage and test time of the battery cell blue film in the insulation value measuring device are obtained.

[0033] Step S103: Acquire actual working information of the battery cell blue film.

[0034] After obtaining the test information of the battery cell blue film before failure, the actual working information of the battery cell blue film during normal operation can be obtained, that is, the actual operating temperature and actual profile voltage of the battery cell blue film during normal operation of the battery can be obtained.

[0035] Step S104: obtaining the estimated life of the battery cell blue film after contacting the coolant based on the test information and the actual working information.

[0036] After obtaining the test information and actual working information of the battery cell blue film, the estimated life of the battery cell blue film after contact with the coolant can be calculated based on the test information and the actual working information. The specific calculation process is described below and will not be described in detail here.

[0037] Different from the prior art, the life estimation method of the battery cell blue film of the present application includes: obtaining the insulation value change trend after the battery cell blue film comes into contact with the coolant; obtaining the test information of the battery cell blue film before failure based on the insulation value change trend; obtaining the actual working information of the battery cell blue film; obtaining the estimated life of the battery cell blue film after contact with the coolant based on the test information and the actual working information. Through the above methods, the life estimation method of the battery cell blue film of the present application can quickly obtain the estimated life of the battery cell blue film after contact with the coolant, shorten the test time for obtaining the life of the battery cell blue film, and reduce the test cost.

[0038] Optionally, a method for obtaining a change trend of the insulation value of the battery cell blue film after contact with the coolant is as follows: Figure 2 See Figure 2 , Figure 2 yes Figure 1 Step S101 is a flow chart of an embodiment. Figure 2 As shown, this embodiment can be Figure 2 The steps shown implement step S101, which specifically includes steps S201 to S202:

[0039] Step S201: constructing an insulation value measuring device for a battery cell blue film in which the battery cell blue film and the coolant are in contact with each other.

[0040] In this embodiment, when obtaining the insulation value change trend after the blue film of the battery cell contacts the coolant, it is necessary to construct an insulation value measurement device for the blue film of the battery cell in contact with the coolant. The specific structure of the insulation value measurement device is described below and will not be described in detail here.

[0041] Step S202: using a battery cell blue film insulation value measuring device to measure the insulation value of the battery cell blue film in contact with the coolant to obtain a trend of insulation value changes.

[0042] In this embodiment, the insulation value of the blue film of the battery cell in contact with the coolant can be measured by using the battery cell blue film insulation value measuring device to obtain the insulation value change trend.

[0043] The specific process of obtaining the insulation value change trend is as follows:

[0044] Before obtaining the insulation value change trend of the battery cell blue film in contact with the coolant, it is first necessary to perform an operating condition analysis on the battery cell corresponding to the battery cell blue film to obtain the temperature distribution of the battery cell life cycle and determine the voltage operating profile corresponding to the battery cell. In addition, it is also necessary to analyze the layout of the battery liquid cooling system, the piping material, and whether there are leakage detection and prevention measures to determine the volume of coolant in contact with the battery cell blue film.

[0045] After confirming the above situation, the cell blue film insulation value measurement device can be set up based on the above working condition analysis, voltage working profile and coolant volume to test and obtain the insulation value change trend of the cell blue film under a given working condition and a given voltage profile over a period of time. In addition, based on the insulation value change trend, the insulation value change trend over a longer period can be obtained through data analysis and modeling.

[0046] Optionally, a method for obtaining test information of a battery cell blue film before failure based on a variation trend of the insulation value is as follows: Figure 3 See Figure 3 , Figure 3 yes Figure 1Step S102 is a flow chart of an embodiment. Figure 3 As shown, this embodiment can be Figure 3 The steps shown implement step S102, which specifically includes steps S301 to S302:

[0047] Step S301: Determine the failure insulation resistance of the blue film of the battery cell.

[0048] After obtaining the insulation value change trend over a period of time under given working conditions and a given voltage profile through data analysis and modeling to obtain the insulation value change trend over a longer period, the failure insulation resistance value when the blue film of the battery cell fails under the given working conditions and a given voltage profile can be determined.

[0049] Step S302: Acquire test information of the blue film of the battery cell when the insulation value variation trend is greater than or equal to the failure insulation resistance.

[0050] At this time, if the insulation value change trend can reach the failure insulation resistance value, the test information of the battery cell blue film undergoing aging can be obtained when the insulation value change trend is greater than or equal to the failure insulation resistance value. The test information includes the test condition temperature, test profile voltage and test time.

[0051] Optionally, a method for obtaining an estimated life span of a battery cell blue film after contact with a coolant based on test information and actual working information is as follows: Figure 4 See Figure 4 , Figure 4 yes Figure 1 Step S104 is a flow chart of an embodiment. In this embodiment, the actual working information includes the actual use temperature and the actual profile voltage, and the test information includes the test operating temperature, the test profile voltage and the test time. Figure 4 The steps shown implement step S104, which specifically includes steps S401 to S403:

[0052] Step S401: Obtain the temperature acceleration factor of the blue film of the battery cell based on the actual use temperature and the test condition temperature.

[0053] After obtaining the actual temperature of the battery cell blue film under the thermometer test condition, the two can be input into the Arrhenius acceleration model to calculate the temperature acceleration factor of the battery cell blue film. In this embodiment, the temperature acceleration factor refers to the ratio of the degree of enhancement of the chemical reaction rate of a substance to the multiple of the temperature increase within a certain temperature range. It is usually used to measure the sensitivity of the chemical reaction rate to temperature changes.

[0054] Step S402: Obtaining the voltage acceleration factor of the blue film of the battery cell based on the actual profile voltage and the test profile voltage.

[0055] After obtaining the actual cross-sectional voltage and the test cross-sectional voltage of the cell blue film, the two can be input into the voltage acceleration model to calculate the voltage acceleration factor of the cell blue film. In this embodiment, the voltage acceleration factor refers to the degree of influence of voltage on the movement speed of particles in the accelerator.

[0056] Step S403: Obtaining an estimated lifespan based on the temperature acceleration factor, the voltage acceleration factor, and the test time.

[0057] After obtaining the temperature acceleration factor, voltage acceleration factor and test time, the estimated life of the battery cell blue film under a given operating temperature and a given voltage profile can be obtained by calculation based on the three. The specific calculation method is described below and will not be described in detail here.

[0058] Optionally, a method for obtaining the temperature acceleration factor of the battery blue film based on the actual use temperature and the test condition temperature is as follows: Figure 5 See Figure 5 , Figure 5 yes Figure 4 Step S401 is a flow chart of an embodiment. Figure 5 As shown, this embodiment can be Figure 5 The steps shown implement step S401, which specifically includes steps S501 to S502:

[0059] Step S501: Obtain the activation energy and Boltzmann constant of the battery cell blue film.

[0060] In this embodiment, when calculating the temperature acceleration factor, it is first necessary to obtain the activation energy Ea and the Boltzmann constant k of the blue film of the battery cell, where the activation energy refers to the energy required to make the crystal atoms leave the equilibrium position and migrate to another new equilibrium or non-equilibrium position. It is also called activation energy, which is an indicator that reflects the impact of temperature stress on product life; the Boltzmann constant is an important physical constant used to describe the relationship between temperature and energy.

[0061] Step S502: inputting the activation energy of the blue film of the battery cell, the Boltzmann constant, the actual use temperature and the test condition temperature into the Arrhenius acceleration model to obtain the temperature acceleration factor.

[0062] After obtaining the activation energy Ea, Boltzmann constant k, actual operating temperature Ti and test condition temperature Ttest of the battery cell blue film, the temperature acceleration factor Af1 can be calculated based on the Arrhenius acceleration model. The specific calculation formula is shown in formula (1):

[0063] Af1=exp [-(Ea / k)*(1 / Ttest-1 / Ti)] (1)

[0064] Among them, the function exp represents the natural exponential function, that is, the exponential function with the real number e (e≈2.71828) as the base, Af1 represents the temperature acceleration factor, Ea represents the activation energy of the blue film of the battery cell, Ti represents the actual use temperature, and Ttest represents the test operating temperature.

[0065] Optionally, a method for obtaining a voltage acceleration factor of a battery cell blue film based on the actual profile voltage and the test profile voltage is as follows: Figure 6 See Figure 6 , Figure 6 yes Figure 4 Step S402 is a flow chart of an embodiment. Figure 6 As shown, this embodiment can be Figure 6 The steps shown implement step S402, which specifically includes steps S601 to S602:

[0066] Step S601: Obtain voltage acceleration constant.

[0067] In this embodiment, when calculating the voltage acceleration factor, it is necessary to first obtain the voltage acceleration constant β.

[0068] Step S602: Input the voltage acceleration constant, the actual profile voltage and the test profile voltage into a voltage acceleration model to obtain a voltage acceleration factor.

[0069] After obtaining the voltage acceleration constant β, the actual profile voltage Vi and the test profile voltage Vtest, the voltage acceleration factor Af2 can be calculated based on the voltage acceleration model. The specific calculation formula is shown in formula (2):

[0070] Af2=exp [β*(Vt-Vi)] (2)

[0071] Among them, the function exp represents the natural exponential function, that is, the exponential function with the real number e (e≈2.71828) as the base, β represents the voltage acceleration constant, Af2 represents the voltage acceleration factor, Vi represents the actual profile voltage, and Vtest represents the test profile voltage.

[0072] Optionally, a method for obtaining an estimated life based on a temperature acceleration factor, a voltage acceleration factor, and a test time is as follows: Figure 7 See Figure 7 , Figure 7 yes Figure 4 Step S403 is a flow chart of an embodiment. Figure 7 As shown, this embodiment can be Figure 7 The steps shown implement step S403, which specifically includes steps S701 to S703:

[0073] Step S701: Obtain the ratio of the actual sample to the theoretical sample of the battery cell blue film.

[0074] When calculating the estimated life of the battery blue film, it is first necessary to obtain the actual sample N of the battery blue film. s Ratio N to theoretical sample N0 s / N0. The theoretical sample N0 is given by the acceleration model standard.

[0075] Step S702: Obtain the product of the temperature acceleration factor and the voltage acceleration factor.

[0076] In getting the actual sample N s Ratio N to theoretical sample N0 s / N0, the product AF of the temperature acceleration factor Af2 and the voltage acceleration factor Af2 can be calculated.

[0077] Step S703: Calculate the product of the test time, the product and the ratio to obtain the estimated lifespan.

[0078] Finally, calculate the product AF of the temperature acceleration factor Af2, the voltage acceleration factor Af2, and the actual sample N s Ratio N to theoretical sample N0 s The product of / N0 and the test time Ttest can be used to calculate the estimated life span Lp of the blue film of the battery cell. The specific calculation formula is shown in formula (3):

[0079] Lp=N s / N0*AF*Ttest (3)

[0080] Where Lp is the estimated life of the blue film of the battery cell, N s It represents the actual sample, N0 represents the theoretical sample, AF represents the product of temperature acceleration factor Af2 and voltage acceleration factor Af2, and Ttest represents the test time.

[0081] Optionally, the present application further proposes a life prediction system for a battery cell blue film, see Figure 8 , Figure 8 1 is a schematic diagram of the structure of an embodiment of a life prediction system for a battery cell blue film provided by the present application. Figure 8 As shown, the life prediction system 100 of the battery cell blue film of this embodiment includes an insulation value measuring device 10 and a calculation device 20. The insulation value measuring device 10 is used to obtain the insulation value change trend of the battery cell blue film after it comes into contact with the coolant; the calculation device 20 is connected to the insulation value measuring device 10, and is used to obtain the test information of the battery cell blue film before failure based on the insulation value change trend, obtain the actual working information of the battery cell blue film, and obtain the estimated life of the battery cell blue film based on the test information and the actual working information.

[0082] Optionally, see Fig. 9 , Fig. 9 Schematic diagram of the structure of an insulation value measuring device according to an embodiment of the present application. Fig. 9 As shown, the insulation value measuring device 10 of the present embodiment includes: a safety analysis device 11, a temperature box 12 and a battery pack lower box 13; the battery pack lower box 13 is arranged inside the temperature box 12, and a coolant 15 is provided in the accommodating cavity of the battery pack lower box 13. The battery cell 14 to be tested is arranged in the accommodating cavity of the battery pack lower box 13 and is partially immersed in the coolant 15. The safety analysis device 11 is respectively connected to the battery cell 14 to be tested and the battery pack lower box 13, and is used to measure the insulation value of the battery cell blue film of the battery cell 14 to be tested to obtain the changing trend of the insulation value. The temperature box 12 is used to simulate the ambient temperature of the battery cell to be tested in the battery pack.

[0083] Among them, as mentioned above, before using the insulation value measuring device 10 to obtain the insulation value change trend of the battery cell blue film in contact with the coolant 15, it is first necessary to perform a working condition analysis on the battery cell corresponding to the blue film of the battery cell to obtain the temperature distribution of the battery cell life cycle and determine the voltage working profile corresponding to the battery cell. In addition, it is also necessary to analyze the layout of the battery liquid cooling system, the pipeline material, and whether there are leakage detection and prevention measures to determine the volume of the coolant 15 in contact with the blue film of the battery cell. The specific process is as follows:

[0084] First, it is necessary to analyze the working condition of the battery cell corresponding to the blue film of the battery cell. The working condition of the battery cell refers to the state of the battery cell in the whole life cycle of the battery, which mainly includes the working state and the storage state. The working state is the charging and discharging process of the battery cell. Taking the battery cell of the vehicle as an example, its working state includes continuous charging in the parking state or continuous discharging during driving, and the temperature changes during this process. The storage state is the process of the vehicle being parked and powered off, and the battery cell temperature is affected by the ambient temperature. Therefore, the working condition analysis is mainly the temperature distribution analysis of the battery cell life cycle, and the temperature distribution should include the proportion of each temperature gradient. As shown in Table 1 below:

[0085] Temperature(℃) Proportion <![CDATA[T1]]> <![CDATA[P1]]> <![CDATA[T2]]> <![CDATA[P2]]> <![CDATA[T3]]> <![CDATA[P3]]> … … <![CDATA[T n ]]> <![CDATA[P n ]]>

[0086] Table 1

[0087] Among them, T i (i=1,2,3,…,n) represents the different temperatures of the battery cells, P i (i=1, 2, 3, ..., n) represents the proportion of different temperatures of the battery cell in the life cycle of the battery cell.

[0088] In addition, the temperature distribution of the working state is the temperature collected in the battery management system, and the temperature data of the storage state can be the temperature data distribution within one year based on public meteorological data statistics. The above temperatures can be defined as temperature distribution, and the working time or charge and discharge cycle number of the battery cell can be further obtained based on the temperature distribution. The designed battery life is n days, and the daily charge and discharge cycle number of the battery cell is m times. Then, within the design life, the number of charge and discharge cycles of the battery cell is N = n*m. The number of charge and discharge cycles of the battery cell at different temperatures is shown in Table 2 below:

[0089]

[0090] Table 2

[0091] Among them, T i (i=1,2,3,…,n) represents the different temperatures of the battery cells, P i (i=1, 2, 3, ..., n) represents the proportion of different temperatures of the battery cell in the life cycle of the battery cell, and N represents the total number of charge and discharge cycles of the battery cell.

[0092] Taking the battery cell of a vehicle as an example, after analyzing the working condition of the battery cell, the working profile of the battery cell can be determined according to the vehicle driving, charging, or parking. The different profiles of the vehicle are shown below:

[0093] Section 1: During driving: the battery cell is in a continuous discharge state, the battery cell voltage is in a slow decline process, and the temperature is in an increase process, until the thermal management system starts liquid cooling to maintain the temperature to a stable stage; within the δt1 time, the equilibrium temperature T1=T0+δT, and the battery cell stable voltage V1=V 初始1 -δV;

[0094] Section 2: Charging and recharging process: The battery cell is in a continuous charging state, the battery cell voltage is in a slow rising process, and the temperature is in a rising process until the thermal management system starts liquid cooling to maintain the temperature to a stable stage; within the δt2 time, the equilibrium temperature T2 = T0 + δT, and the battery cell stable voltage V2 = V 初始2 +δV;

[0095] Section 3: Parking power-off process: The battery cell remains stable, and the temperature slowly rises or drops to the ambient temperature. For example, within the δt3 time, the equilibrium temperature T3 = T 0± δT, stable cell voltage V3.

[0096] At this time, after performing the above working condition analysis and determining the voltage working profile corresponding to the battery cell, the layout of the battery liquid cooling system, the pipe material, and whether there are leakage detection and prevention measures are analyzed to determine the volume of the coolant 15 in contact with the battery cell blue film. For example, when the system detects that the pressure of the pipeline is lower than the preset working pressure, it will stop the operation of the liquid cooling system. Assume that the leakage volume at this time is VL , then the volume of the verification coolant 15 is V L .

[0097] After completing the above steps, the insulation value of the blue film of the battery cell in contact with the coolant can be measured using the battery cell blue film insulation value measuring device 10 to obtain the insulation value change trend. The specific process is as follows:

[0098] like Fig. 9 As shown, the battery cell 14 to be tested is placed in the accommodating cavity of the lower box 13 of the battery pack and partially immersed in the coolant 15; a safety analysis device 11 is set, and the voltage operating condition profile loaded between the battery cell and the box is set to be the actual operating condition profile, which is set as follows:

[0099] Setting 1: Condition DC = V 初始1 , the total test time δt1 (including boost, test, and buck time).

[0100] Setting 2: Condition DC = V 初始2 , the total test time δt2 (including boost, test, and buck time).

[0101] Setting 3: Condition DC = V 初始3 , the total test time δt3 (including boost, test, and buck time).

[0102] According to the distribution of temperature, temperature proportion, and number of times of charge and discharge of the battery cell determined in the working condition analysis, the test is carried out according to the following profile (heating / cooling-insulation-insulation resistance measurement); the heating time refers to the time from room temperature to the temperature T in the temperature distribution. i (i=1,2,3,…,n); select the temperature change rate as 3℃ / min; keep warm for the time at temperature T i The time of holding at the temperature T should be greater than the total test time of the three sections δt1, δt2, and δt3; then i Under the condition, the insulation resistance value of the battery cell model is measured under pressure, and the number of loading times is N*Pi (i=1, 2, 3, ..., n).

[0103] Therefore, based on the above method, the present embodiment can use the insulation value measuring device 10 to test the blue film of the battery cell to be tested, so as to obtain the insulation value change trend of the blue film of the battery cell to be tested under a given working condition and a given voltage profile for a period of time. In view of the low resistance of the lower box 13 of the battery pack and the coolant 15, which can be ignored, the insulation resistance R 总 Approximately equal to the insulation resistance Ri of the blue film of the battery cell (i=1, 2, 3, ..., n).

[0104] In addition, after obtaining the insulation value change trend over a period of time under a given operating condition and a given voltage profile, the resistance value change trend over a longer period can also be obtained through data analysis and modeling. At this point, the estimated life of the battery cell blue film after contact with the coolant under a given operating temperature and a given voltage profile can be calculated based on the life estimation method of the battery cell blue film described above.

[0105] Optionally, the present application further proposes a computer-readable storage medium. Fig.10 , Fig.10 It is a structural schematic diagram of an embodiment of a computer-readable storage medium provided by the present application.

[0106] The computer-readable storage medium 200 of the embodiment of the present application stores program instructions 210 therein, and the program instructions 210 are executed by a processor to implement the method for estimating the life of a battery cell blue film in any of the above embodiments.

[0107] Among them, the program instructions 210 can form a program file and be stored in the above-mentioned storage medium in the form of a software product, so that an electronic device (which can be a personal computer, a server, or a network device, etc.) or a processor (processor) executes all or part of the steps of each implementation method of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes, or terminal devices such as computers, servers, mobile phones, tablets, etc.

[0108] The computer-readable storage medium 200 of this embodiment may be, but is not limited to, a USB flash drive, an SD card, a PD optical drive, a mobile hard disk, a large-capacity floppy drive, a flash memory, a multimedia memory card, a server, and the like.

[0109] In one embodiment, a computer program product or computer program is provided, the computer program product or computer program includes computer instructions, the computer instructions are stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device performs the steps in the above-mentioned method embodiments.

[0110] In addition, if the above functions are implemented in the form of software functions and sold or used as independent products, they can be stored in a storage medium readable by a mobile terminal, that is, the present application also provides a storage device storing program data, the program data can be executed to implement the method of the above embodiment, and the storage device can be, for example, a USB flash drive, an optical disk, a server, etc. In other words, the present application can be embodied in the form of a software product, which includes a number of instructions for enabling a smart terminal to execute all or part of the steps of the method described in each embodiment.

[0111] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0112] Any process or method description in a flowchart or otherwise described herein may be understood to represent a mechanism, segment or portion of a code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0113] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (which can be a personal computer, server, network device or other system that can fetch instructions from the instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0114] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for estimating the life of a battery cell blue film, characterized in that: include: Obtain the insulation value change trend after the blue film of the battery cell comes into contact with the coolant; Acquire test information of the battery cell blue film before failure based on the insulation value change trend; Obtaining actual working information of the battery cell blue film; The estimated life of the battery cell blue film after contacting the coolant is obtained based on the test information and the actual working information.

2. The life prediction method according to claim 1, characterized in that: The step of obtaining the insulation value change trend after the blue film of the battery cell contacts the coolant comprises: Constructing an insulation value measuring device for the battery core blue film in which the battery core blue film and the coolant are in contact with each other; The insulation value of the battery cell blue film in contact with the coolant is measured using the battery cell blue film insulation value measuring device to obtain the insulation value change trend.

3. The life prediction method according to claim 1, characterized in that: The step of obtaining the test information of the battery cell blue film before failure based on the insulation value change trend includes: Determining the failure insulation resistance of the blue film of the battery cell; Acquire test information of the blue film of the battery cell when the insulation value variation trend is greater than or equal to the failure insulation resistance value.

4. The life prediction method according to claim 1, characterized in that: The actual working information includes the actual use temperature and the actual profile voltage, and the test information includes the test operating temperature, the test profile voltage and the test time; The step of obtaining the estimated life of the battery cell blue film after contacting the coolant based on the test information and the actual working information includes: Obtaining a temperature acceleration factor of the battery cell blue film based on the actual use temperature and the test operating temperature; Obtaining a voltage acceleration factor of the battery cell blue film based on the actual profile voltage and the test profile voltage; The estimated lifespan is obtained based on the temperature acceleration factor, the voltage acceleration factor, and the test time.

5. The life prediction method according to claim 4, characterized in that: The step of obtaining the temperature acceleration factor of the battery cell blue film based on the actual use temperature and the test operating condition temperature includes: Obtaining the activation energy and Boltzmann constant of the battery cell blue film; The activation energy of the battery cell blue film, the Boltzmann constant, the actual use temperature and the test operating temperature are input into the Arrhenius acceleration model to obtain the temperature acceleration factor.

6. The life prediction method according to claim 4, characterized in that: The step of obtaining the voltage acceleration factor of the battery cell blue film based on the actual profile voltage and the test profile voltage includes: Get the voltage acceleration constant; The voltage acceleration constant, the actual profile voltage and the test profile voltage are input into a voltage acceleration model to obtain the voltage acceleration factor.

7. The life prediction method according to claim 4, characterized in that: The step of obtaining the estimated life based on the temperature acceleration factor, the voltage acceleration factor and the test time includes: Obtaining the ratio of the actual sample to the theoretical sample of the battery cell blue film; Obtaining the product of the temperature acceleration factor and the voltage acceleration factor; The test time, the product and the ratio are calculated to obtain the estimated lifespan.

8. A life prediction system for a battery cell blue film, characterized in that: include: Insulation value measuring device, used to obtain the insulation value change trend after the blue film of the battery cell comes into contact with the coolant; A computing device is connected to the insulation value measuring device, and is used to obtain the test information of the battery cell blue film before failure based on the insulation value change trend, obtain the actual working information of the battery cell blue film, and obtain the estimated life of the battery cell blue film based on the test information and the actual working information.

9. The life prediction system according to claim 8, characterized in that: The insulation value measuring device includes a safety analysis device, a temperature box and a battery pack lower box; the battery pack lower box is arranged inside the temperature box, and a coolant is provided in the accommodating cavity of the battery pack lower box. The battery cell to be tested is arranged in the accommodating cavity of the battery pack lower box and is partially immersed in the coolant. The safety analysis device is respectively connected to the battery cell to be tested and the battery pack lower box, and is used to measure the insulation value of the battery cell blue film of the battery cell to be tested to obtain the changing trend of the insulation value. The temperature box is used to simulate the ambient temperature of the battery cell to be tested in the battery pack.

10. A computer-readable storage medium, characterized in that: Program instructions are stored therein, and the program instructions are executed to implement the life estimation method of the battery cell blue film as described in any one of claims 1-7.

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