A parameter determination method and apparatus

Abstract

The application discloses a parameter determination method and device, and relates to the technical field of electric vehicles. The method comprises the following steps: determining a first coefficient according to test data of a first test, wherein the first test is a test in which a battery reaches thermal equilibrium under the same initial battery temperature, different ambient temperatures and different cooling liquid temperatures; determining a second coefficient according to test data of a second test, wherein the second test is a test in which the battery reaches thermal equilibrium under the same initial battery temperature, the same cooling liquid temperature and different ambient temperatures; determining a temperature curve for realizing thermal equilibrium of the battery according to the first coefficient, the second coefficient and a predefined thermal equilibrium relationship; and determining the shortest time required for the battery to reach thermal equilibrium under different ambient temperatures, and corresponding cooling liquid temperatures and third thermal equilibrium temperatures according to the temperature curve. The scheme shortens the test period, reduces the cost input and is convenient to operate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric vehicles, and in particular to a parameter determination method and device. BACKGROUND

[0002] With the increasingly prominent world energy crisis and environmental protection problems, the automobile industry is facing severe challenges. However, new energy vehicles will become an important direction for future vehicle development due to their low pollution, low noise and other advantages. As the main driving force of new energy vehicles, the performance of power batteries is greatly affected by temperature. When the temperature of the battery is within an appropriate temperature range, the power and economy of the vehicle can be improved.

[0003] In current thermal management strategies, in order to avoid the power battery being in a low temperature environment, the power battery will be kept warm after the vehicle is fully charged. The commonly used method for this heat preservation strategy is test calibration. This calibration method not only takes time but also has high system-level test cost. SUMMARY

[0004] The purpose of the present application is to provide a parameter determination method and device, thereby solving the problem of time-consuming and high cost of parameter calibration in the prior art.

[0005] In order to achieve the above purpose, the present application provides a parameter determination method, comprising:

[0006] determining a first coefficient according to test data of a first test, wherein the first test is a test in which the battery reaches thermal equilibrium under the same initial battery temperature, different ambient temperatures and different coolant temperatures;

[0007] determining a second coefficient according to test data of a second test, wherein the second test is a test in which the battery reaches thermal equilibrium under the same initial battery temperature, the same coolant temperature and different ambient temperatures;

[0008] determining a temperature curve for achieving thermal equilibrium of the battery according to the first coefficient, the second coefficient and a predefined thermal equilibrium relationship;

[0009] determining the shortest time required for the battery to reach thermal equilibrium under different ambient temperatures, and the corresponding coolant temperature and third thermal equilibrium temperature according to the temperature curve.

[0010] Optionally, the test data of the first test includes a first thermal equilibrium temperature when the battery reaches thermal equilibrium, an ambient temperature of the first test and a coolant temperature of the first test.

[0011] Optionally, the determining of the first coefficient according to the test data of the first test comprises:

[0012] calculating a first difference between the first thermal equilibrium temperature and an ambient temperature corresponding to the first thermal equilibrium temperature;

[0013] calculating a second difference between the first thermal equilibrium temperature and a coolant temperature corresponding to the first thermal equilibrium temperature;

[0014] determining the first coefficient according to the second difference and the first difference.

[0015] Optionally, the determining the first coefficient according to the second difference and the first difference comprises:

[0016] calculating a first ratio of each of the second differences and the first differences corresponding to the second differences;

[0017] fitting a plurality of the first ratios to determine the first coefficient.

[0018] Optionally, the test data of the second test comprises a first time length required for the battery to reach thermal equilibrium, a second thermal equilibrium temperature, an initial battery temperature of the second test, and an ambient temperature of the second test.

[0019] Optionally, the determining the second coefficient according to the test data of the second test comprises:

[0020] calculating a third difference between each of the ambient temperatures and the initial battery temperature in the second test;

[0021] calculating a fourth difference between each of the ambient temperatures and a second thermal equilibrium temperature corresponding to the ambient temperatures in the second test;

[0022] calculating a first average of each of the third differences and the fourth differences corresponding to the third differences;

[0023] determining a first temperature coefficient of ambient temperature to the battery according to each of the fourth differences and a first time length corresponding to the fourth differences;

[0024] determining the second coefficient according to the first temperature coefficient and the first average.

[0025] Optionally, the determining the second coefficient according to the first temperature coefficient and the first average comprises:

[0026] calculating a third ratio of the first temperature coefficient and the first average corresponding to the first temperature coefficient;

[0027] fitting a plurality of the third ratios to determine the second coefficient.

[0028] Optionally, the determining the temperature curve achieving the battery thermal equilibrium according to the first coefficient, the second coefficient and the predefined thermal equilibrium relationship comprises:

[0029] determining a third coefficient according to the first coefficient and the second coefficient, the third coefficient being a ratio of a second temperature coefficient of the battery to the cooling liquid temperature to a fifth difference value, the fifth difference value being a difference between the real-time temperature of the battery and the cooling liquid temperature;

[0030] determining the temperature curve according to the second coefficient, the third coefficient and the thermal equilibrium relationship.

[0031] Optionally, the relational expression corresponding to the temperature curve is: T bat_k+1 = [a1*(T env -T bat )-a2*(T bat -T water )]*Δt+T bat_k ; wherein T bat _ k+1 represents the calculated temperature of the battery at k+1 time, a1 represents the second coefficient, a2 represents the third coefficient, T bat_k represents the temperature of the battery at k time, Δt represents a time interval between k+1 time and k time, T env represents the ambient temperature, and T water represents the cooling liquid temperature.

[0032] In a second aspect, the embodiments of the present application further provide a parameter determination device, comprising:

[0033] a first determination module configured to determine a first coefficient according to test data of a first test, wherein the first test is a test in which a battery reaches thermal equilibrium under the same initial battery temperature, different ambient temperatures and different cooling liquid temperatures;

[0034] a second determination module configured to determine a second coefficient according to test data of a second test, wherein the second test is a test in which the battery reaches thermal equilibrium under the same initial battery temperature, the same cooling liquid temperature and different ambient temperatures;

[0035] a third determination module configured to determine a temperature curve achieving the battery thermal equilibrium according to the first coefficient, the second coefficient and a predefined thermal equilibrium relationship;

[0036] a fourth determination module configured to determine, according to the temperature curve, a shortest time required for the battery to reach thermal equilibrium under different ambient temperatures and corresponding cooling liquid temperatures and third thermal equilibrium temperatures.

[0037] In a third aspect, the embodiments of the present application further provide a parameter determination device, comprising: a transceiver, a processor, a memory, and a program or instruction stored in the memory and executable in the processor; the processor implements the parameter determination method according to the first aspect when executing the program or instruction.

[0038] In a fourth aspect, the embodiments of the present application further provide a readable storage medium, having a program or instruction stored therein, the program or instruction being executable in a processor to implement the parameter determination method according to the first aspect.

[0039] The above technical solutions of the present application have at least the following beneficial effects:

[0040] The parameter determination method of the embodiments of the present application first determines a first coefficient according to test data of a first test, wherein the first test is a test in which a battery reaches thermal equilibrium under the same initial battery temperature, different ambient temperatures and different coolant temperatures; secondly, a second coefficient is determined according to test data of a second test, wherein the second test is a test in which the battery reaches thermal equilibrium under the same initial battery temperature, the same coolant temperature and different ambient temperatures; then, a temperature curve for achieving thermal equilibrium of the battery is determined according to the first coefficient, the second coefficient and a predefined thermal equilibrium relationship; in this way, a process curve for reaching thermal equilibrium of the battery is fitted based on test data and an algorithm; finally, the shortest time required for the battery to reach thermal equilibrium under different ambient temperatures, and the corresponding coolant temperature and third thermal equilibrium temperature are determined according to the temperature curve. In this way, the test period can be shortened, the cost investment is reduced and the operation is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 Fig. 1 is a flowchart of a parameter determination method according to an embodiment of the present application;

[0042] Figure 2 Fig. 2 is another flowchart of a parameter determination method according to an embodiment of the present application;

[0043] Figure 3 Fig. 3 is a structural diagram of a parameter determination device according to an embodiment of the present application;

[0044] Figure 4 Fig. 4 is a structural diagram of a parameter determination device according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0046] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a particular order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein. In addition, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in a "or" relationship.

[0047] At present, most of the power batteries loaded by existing new energy vehicles are lithium ion batteries, and the lithium ion battery is very sensitive to temperature. It needs a suitable working temperature range. Once the temperature exceeds or is lower than this temperature range, its electrical performance will be greatly affected. When the ambient temperature is 0℃ or below, not only the available power of the power battery will be reduced, resulting in the reduction of the vehicle's endurance mileage, but also the output power of the power battery will be reduced, thereby affecting the power performance of the whole vehicle, resulting in the limitation of the vehicle's performance such as acceleration performance, climbing performance, etc. At this time, the battery thermal management needs to start the active insulation function to provide a suitable temperature for the battery and ensure its performance. Therefore, the design and verification of the active insulation function of the power battery is particularly important.

[0048] Based on the above situation, the embodiment of the present application provides a parameter determination method and device. In the following, the parameter determination method and device provided by the embodiment of the present application are described in detail through specific embodiments and application scenarios.

[0049] As shown in the flowchart of the parameter determination method of the embodiment of the present application, the parameter is a parameter for realizing battery thermal balance, that is, a parameter used in the process of controlling the battery to reach a thermal balance state from a current state when the battery is in an excessively high or low ambient temperature. The method comprises: Figure 1 Step 101, determining a first coefficient according to the test data of a first test, wherein the first test is a test of the battery reaching thermal balance under the same initial battery temperature, different ambient temperatures and different cooling liquid temperatures;

[0050] That is, in this step, the first coefficient is obtained by test calibration; for example, in a low temperature environment, different environmental temperature conditions and cooling liquid temperature conditions are designed for testing to obtain the first coefficient according to the test results, wherein the first coefficient is related to the thermal balance relationship of the battery.

[0051]

[0052] ​Step 102, determining a second coefficient according to test data of a second test, wherein the second test is a test of reaching thermal equilibrium of the battery under the same initial battery temperature, the same coolant temperature and different ambient temperatures;

[0053] Similarly, the second coefficient is also obtained by test calibration in this step, for example, by setting different ambient temperature conditions for test to obtain the second coefficient according to the test results, wherein the second coefficient is also related to the thermal equilibrium relationship of the battery, and specifically, for example, the second coefficient is a coefficient in the thermal equilibrium relationship.

[0054] Step 103, determining a temperature curve for achieving thermal equilibrium of the battery according to the first coefficient, the second coefficient and a predefined thermal equilibrium relationship;

[0055] In this step, the temperature curve is a process curve of the battery from the current state to the thermal equilibrium state; wherein the thermal equilibrium relationship can refer to the relationship between the ambient temperature coefficient of temperature drop / rise of the power battery and the coolant temperature coefficient of temperature rise / drop of the battery.

[0056] Taking a low-temperature environment as an example, the ambient temperature coefficient of temperature drop of the power battery is defined as P1, wherein P1=a1*(Tenv-Tbat); the coolant temperature coefficient of temperature rise of the power battery is defined as P2, wherein P2=a2*(Tbat-Twater); then when the battery reaches thermal equilibrium, P1=P2; based on the above, the thermal equilibrium relationship is: a1*(Tenv-Tbat)=a2*(Tbat-Twater). Wherein, Tenv represents the ambient temperature, Twater represents the coolant temperature, and Tbat represents the battery temperature.

[0057] Step 104, determining the shortest time required for the battery to reach thermal equilibrium under different ambient temperatures, and the corresponding coolant temperature and third thermal equilibrium temperature according to the temperature curve.

[0058] This step specifically determines the coolant temperature value required by the battery, the thermal equilibrium temperature value when the battery reaches thermal equilibrium and the time length required for the battery to reach thermal equilibrium under different ambient temperature values according to the temperature curve, so that a corresponding relationship table can be generated, so that the battery management system of the electric vehicle can achieve thermal equilibrium of the battery based on the corresponding relationship table.

[0059] The parameter determination method of the embodiment of the application first determines a first coefficient according to test data of a first test, wherein the first test is a test in which a battery reaches thermal equilibrium under the same initial battery temperature, different ambient temperatures and different coolant temperatures; second, determines a second coefficient according to test data of a second test, wherein the second test is a test in which the battery reaches thermal equilibrium under the same initial battery temperature, the same coolant temperature and different ambient temperatures; then, determines a temperature curve for achieving thermal equilibrium of the battery according to the first coefficient, the second coefficient and a predefined thermal equilibrium relationship; in this way, a process curve for reaching thermal equilibrium of the battery is fitted based on test data and an algorithm; finally, determines the shortest time required for the battery to reach thermal equilibrium under different ambient temperatures and corresponding coolant temperatures and third thermal equilibrium temperatures according to the temperature curve. In this way, the battery heat preservation scheme is tested and verified based on the combination of test calibration and logical algorithm, and compared with the test calibration of the battery heat preservation scheme, the embodiment of the application can shorten the test period, reduce the cost investment and facilitate operation.

[0060] As an optional implementation, the test data of the first test includes a first thermal equilibrium temperature when the battery reaches thermal equilibrium, an ambient temperature of the first test and a coolant temperature of the first test.

[0061] That is, in the embodiment of the application, the first coefficient needs to be determined based on the first thermal equilibrium temperature, the ambient temperature and the coolant temperature; wherein, in the process of determining the first coefficient, a logical algorithm for determining thermal equilibrium of the battery is also needed.

[0062] On the basis of the foregoing thermal equilibrium relationship a1*(Tenv-Tbat)=a2*(Tbat-Twater), the following content can be obtained:

[0063] Definition: ΔT1=Tenv-Tbat, ΔT2=Tbat-Twater; then: the foregoing thermal equilibrium relationship can be converted into a1*ΔT1=a2*ΔT2; therefore, a1 and a2 can be defined as follows: On this basis, as a specific implementation, step 101, determining a first coefficient according to test data of a first test, includes:

[0064] calculating a first difference between the first thermal equilibrium temperature and an ambient temperature corresponding to the first thermal equilibrium temperature; in this step, the first thermal equilibrium temperature is the thermal equilibrium temperature of the battery when reaching a thermal equilibrium state in the first test under the ambient temperature corresponding to the first thermal equilibrium temperature;

[0065] a second difference value between the first heat balance temperature and a coolant temperature corresponding to the first heat balance temperature is calculated; in this step, the first heat balance temperature is the heat balance temperature of the battery when the battery reaches a heat balance state in the first test at the coolant temperature corresponding to the first heat balance temperature,

[0066] According to the above two steps, the first difference value and the second difference value are calculated based on the ambient temperature, the coolant temperature and the heat balance temperature in the same test, so the first difference value is the opposite of the aforementioned ΔT1, and the second difference value is the opposite of the aforementioned ΔT2; of course, the above two steps of the optional implementation manner can also obtain the difference between the ambient temperature and the first heat balance temperature, and the difference between the coolant temperature and the first heat balance temperature.

[0067] According to the second difference value and the first difference value, the first coefficient is determined.

[0068] As a more specific implementation, according to the second difference value and the first difference value, the first coefficient is determined, including:

[0069] A first ratio of each of the second difference value and the first difference value corresponding to the second difference value is calculated.

[0070] The first ratios are fitted to determine the first coefficient, which is the aforementioned parameter K.

[0071] In this more specific implementation, the coefficient K can be obtained by test fitting, and here the test calibration guarantees three points, for example, different ambient temperatures Tenv, the same initial battery temperature Tbat0, and different coolant temperatures Twater can be used for heat preservation tests, and an example of the first test is shown in Table 1 below, wherein Tbat_pre represents the first heat balance temperature, and t represents the length of time required for the battery to reach a heat balance state:

[0072] Table 1

[0073] Serial number Tenv Tbat0 Twater Tbat_pre t 1 -30 0 30 17.18 17791 2 -20 0 20 11.54 13751 3 -10 0 10 5.8 12754

[0074] From the above Table 1, the calculation results of Table 2 below can be obtained:

[0075] Table 2

[0076] Tenv-Tbat_pre Tbat_pre-Twater -47.18 -12.82 -31.54 -8.46 -15.8 -4.2

[0077] Among them, according to the results of Table 2, the first coefficient K = 0.2703 can be fitted.

[0078] As an optional implementation, the test data of the second test includes a first time length required for the battery to reach thermal equilibrium, a second thermal equilibrium temperature, an initial battery temperature of the second test, and an ambient temperature of the second test.

[0079] That is, in the embodiment of the application, the second coefficient needs to be determined based on the first time length, the second thermal equilibrium temperature, the initial battery temperature, and the ambient temperature. Specifically, the second coefficient is a1 in the aforementioned thermal equilibrium relationship. Therefore, in the process of determining the second coefficient, the pre-determined logical algorithm for battery thermal equilibrium also needs to be used.

[0080] As a specific implementation, step 102, determining the second coefficient according to the test data of the second test, includes:

[0081] calculating a third difference value between each of the ambient temperatures and the initial battery temperature in the second test;

[0082] calculating a fourth difference value between each of the ambient temperatures and the second thermal equilibrium temperature corresponding to the ambient temperature in the second test. Similarly, the second thermal equilibrium temperature corresponding to the ambient temperature refers to the thermal equilibrium temperature when the battery reaches thermal equilibrium at the ambient temperature;

[0083] calculating a first average value of each of the third difference values and the fourth difference value corresponding to the third difference value. In this step, the third difference value and the fourth difference value refer to the difference values obtained based on the ambient temperature, the initial battery temperature, and the second thermal equilibrium temperature in the same test.

[0084] determining a first temperature coefficient of the ambient temperature to the battery according to each of the fourth difference values and the first time length corresponding to the fourth difference value; for example, the first temperature coefficient is P1 mentioned above;

[0085] determining the second coefficient according to the first temperature coefficient and the first average value.

[0086] As a more specific implementation, the determining of the second coefficient according to the first temperature coefficient and the first average value includes:

[0087] calculating a third ratio of the first temperature coefficient and the first average value corresponding to the first temperature coefficient;

[0088] fitting a plurality of the third ratios to determine the second coefficient.

[0089] Next, the two optional implementations are described with a specific example:

[0090] The second test is a holding test at different ambient temperatures (Tenv), the same initial battery temperature (Tbat0), and the same cooling liquid temperature (Twater). When the battery reaches thermal equilibrium, the battery temperature (Tbat_pre) and the time (t) required to reach thermal equilibrium are recorded. Three groups of holding tests are tested respectively, as shown in Table 3 below:

[0091] Table 3

[0092] Serial number Tenv Tbat0 Twater Tbat_pre t 1 -30 0 10 2.14 5644 2 -20 0 10 3.96 9601 3 -10 0 10 5.8 12754

[0093] From the content of Table 3 above, the content of Table 4 below can be calculated:

[0094] Table 4

[0095]

[0096] Where (Tenv-Tbat) mean = [(Tenv-Tbat0)+(Tenv-Tbat_pre)] / 2, P1 mean = (Tenv-Tbat_pre) / t, and the second coefficient a1 = 0.0001534 can be obtained by fitting (Tenv-Tbat) mean and P1 mean.

[0097] As an optional implementation, step 104, determining a temperature curve for achieving battery thermal equilibrium according to the first coefficient, the second coefficient, and a predefined thermal equilibrium relationship, includes:

[0098] According to the first coefficient and the second coefficient, a third coefficient is determined, which is the ratio of the second temperature coefficient of the cooling liquid temperature to the battery and the fifth difference value, and the fifth difference value is the difference between the real-time temperature of the battery and the cooling liquid temperature; That is, the third coefficient is the aforementioned parameter a2;

[0099] As mentioned earlier, the first coefficient is the aforementioned parameter K, and the second coefficient is the aforementioned parameter a1; based on the aforementioned formula The third coefficient can be obtained At this point, the coefficients a1 and a2 in the thermal equilibrium relationship can be obtained based on the test data and the pre-determined logical algorithm.

[0100] According to the second coefficient, the third coefficient, and the thermal equilibrium relationship, the temperature curve is determined.

[0101] It should be noted here that based on the aforementioned thermal equilibrium relationship, it can be known that the temperature of the battery at the next time is related to the influence of the ambient temperature on the temperature of the battery, the influence of the cooling liquid temperature on the temperature of the battery, and the current temperature of the battery. That is: T bat_k+1 = (P1-P2)*Δt+T bat_k; Through the above logical derivation, finally the change curve of the battery temperature with the heat preservation time during the heat preservation process can be obtained, wherein Δt is the time interval of adjacent two time points. At the beginning of the calculation, an initial temperature value (Tbat0) of the battery is given, and the real-time temperature Tbat_pre of the battery can be calculated through the formula T bat_k+1 =(P1-P2)*Δt+T bat_k until the temperature of the battery reaches equilibrium.

[0102] Therefore, as a specific implementation, the relationship corresponding to the temperature curve is: T bat_k+1 =[a1*(T env -T bat )-a2*(T bat -T water )]*Δt+T bat_k ; wherein T bat _ k+1 represents the calculated temperature of the battery at k+1 time point, a1 represents the second coefficient, a2 represents the third coefficient, T bat_k represents the temperature of the battery at k time point, Δt represents the time interval between k+1 time point and k time point, T env represents the ambient temperature, and T water represents the coolant temperature.

[0103] The core of the above relationship is iterative calculation, which can quickly obtain the time and temperature when the battery reaches thermal equilibrium, and the battery temperature change curve during the thermal equilibrium process is obtained. Moreover, by adjusting the ambient temperature (Tenv) and the coolant temperature (Twater), the temperature and time when the battery reaches thermal equilibrium under different ambient temperatures and different coolant temperatures (with a certain flow rate) are optimized, and the optimal coolant temperature under which the battery reaches thermal equilibrium in the shortest time is obtained, thereby providing a basis for thermal management and energy optimization of the power battery system.

[0104] Next, the parameter determination method of the embodiment of the application will be described in combination with Figure 2

[0105] Step 201, the formula T bat_k+1 is obtained through theoretical derivation, wherein, as described above, T bat_k+1 =(P1-P2)*Δt+T bat_k =[a1*(T env -T bat )-a2*(T bat -T water )]*Δt+T bat_k ;

[0106] ​Step 202, test calibration coefficients a1 (a2) and K; the specific calibration process can be referred to the examples described above for each optional implementation method.

[0107] Step 203, assign the value to T bat_k+1 Among them, T bat_k+1 This indicates the battery temperature or battery thermal equilibrium temperature calculated in real time by the algorithm.

[0108] Step 204, calculate and obtain T for the heat preservation process. bat_k+1 The curve with respect to t;

[0109] Step 205: Adjust Tenv and Twater to obtain the optimized T. bat_k+1 The curve with respect to t.

[0110] The parameter determination method in this application obtains the temperature (Tbat) and time (t) for the battery to reach thermal equilibrium during active heat preservation through a logical algorithm. Furthermore, by adjusting the ambient temperature (Tenv) and coolant temperature (Twater), the method optimizes the temperature and time for the battery to reach thermal equilibrium under different ambient temperatures and coolant temperatures (with a constant flow rate). This yields the optimal coolant temperature that minimizes the time required for the battery to reach thermal equilibrium, providing a basis for thermal management and energy optimization of power battery systems. The method utilizes multiple coefficients involved in the experimental calibration logical algorithm, increasing the accuracy of theoretical calculations and shortening the testing cycle for verifying battery heat preservation schemes through simple experimental calibration. This reduces cost and simplifies operation.

[0111] like Figure 3 As shown in the figure, this application embodiment also provides a parameter determination device, including:

[0112] The first determining module 301 is used to determine a first coefficient based on the test data of the first test, wherein the first test is a test in which the battery reaches thermal equilibrium under the same initial battery temperature, different ambient temperatures and different coolant temperatures;

[0113] The second determining module 302 is used to determine the second coefficient based on the test data of the second test, wherein the second test is a test in which the battery reaches thermal equilibrium under the same initial battery temperature, the same coolant temperature and different ambient temperatures.

[0114] The third determining module 303 is used to determine the temperature curve for achieving battery thermal balance based on the first coefficient, the second coefficient and the predefined thermal balance relationship;

[0115] The fourth determining module 304 is used to determine, based on the temperature curve, the shortest time required for the battery to reach thermal equilibrium under different ambient temperatures, as well as the corresponding coolant temperature and the third thermal equilibrium temperature.

[0116] Optionally, the test data of the first test comprises a first thermal equilibrium temperature when the battery reaches thermal equilibrium, an ambient temperature of the first test, and a coolant temperature of the first test.

[0117] Optionally, the first determining module 301 comprises:

[0118] a first calculating sub-module, configured to calculate a first difference between the first thermal equilibrium temperature and an ambient temperature corresponding to the first thermal equilibrium temperature;

[0119] a second calculating sub-module, configured to calculate a second difference between the first thermal equilibrium temperature and a coolant temperature corresponding to the first thermal equilibrium temperature;

[0120] a first determining sub-module, configured to determine the first coefficient according to the second difference and the first difference.

[0121] Optionally, the first determining sub-module comprises:

[0122] a first calculating unit, configured to calculate a first ratio of each of the second differences and the first difference corresponding to the second difference;

[0123] a first determining unit, configured to fit a plurality of the first ratios to determine the first coefficient.

[0124] Optionally, the test data of the second test comprises a first duration required for the battery to reach thermal equilibrium, a second thermal equilibrium temperature, an initial battery temperature of the second test, and an ambient temperature of the second test.

[0125] Optionally, the second determining module 302 comprises:

[0126] a third calculating sub-module, configured to calculate a third difference between each of the ambient temperatures and the initial battery temperature in the second test;

[0127] a fourth calculating sub-module, configured to calculate a fourth difference between each of the ambient temperatures and a second thermal equilibrium temperature corresponding to the ambient temperature in the second test;

[0128] a fifth calculating sub-module, configured to calculate a first average of each of the third differences and the fourth difference corresponding to the third difference;

[0129] a second determining sub-module, configured to determine a first temperature coefficient of the ambient temperature to the battery according to each of the fourth differences and a first duration corresponding to the fourth difference;

[0130] a third determining sub-module, configured to determine the second coefficient according to the first temperature coefficient and the first average.

[0131] Optionally, the third determining submodule includes:

[0132] The second calculation unit is used to calculate the third ratio between the first temperature coefficient and the first mean value corresponding to the first temperature coefficient;

[0133] The second determining unit is used to fit the plurality of the third ratios to determine the second coefficient.

[0134] Optionally, the third determining module 303 includes:

[0135] The fourth determining submodule is used to determine a third coefficient based on the first coefficient and the second coefficient. The third coefficient is the ratio of the second temperature coefficient of the coolant temperature to the battery to the fifth difference, and the fifth difference is the difference between the real-time temperature of the battery and the coolant temperature.

[0136] The fifth determining submodule is used to determine the temperature curve based on the second coefficient, the third coefficient, and the thermal balance relationship.

[0137] Optionally, the relationship corresponding to the temperature curve is: T bat_k+1 =[a1*(T env -T bat )-a2*(T bat -T water )]*Δt+T bat_k Among them, T bat _ k+1 This represents the calculated temperature of the battery at time k+1, where a1 represents the second coefficient, a2 represents the third coefficient, and T represents the temperature of the battery at time k+1. bat_k T represents the temperature of the battery at time k, Δt represents the time interval between time k+1 and time k, and T represents the temperature of the battery at time k. env Indicates ambient temperature, T water This indicates the temperature of the coolant.

[0138] It should be noted that the parameter determination device provided in this application embodiment can implement all the method steps implemented in the above parameter determination method embodiment and can achieve the same technical effect. Here, the parts that are the same as those in the method embodiment and the beneficial effects will not be described in detail.

[0139] like Figure 4 As shown, this application embodiment also provides a parameter determination device, including a transceiver 410, a memory 420, a processor 400, and a computer program stored in the memory 420 and running on the processor 400. When the processor 400 executes the computer program, it implements the various processes of the time synchronization method embodiment described above and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0140] The transceiver 410 is used to receive and send data under the control of the processor 400.

[0141] Among them, Figure 4 In this context, the bus architecture can include any number of interconnected buses and bridges, specifically linking various circuits of one or more processors represented by processor 400 and memory represented by memory 420. The bus architecture can also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. The bus interface provides an interface. Transceiver 410 can be multiple elements, including transmitters and receivers, providing a unit for communicating with various other devices over a transmission medium. For different devices, the user interface 430 can also be an interface capable of connecting external or internal devices, including but not limited to keypads, displays, speakers, microphones, joysticks, etc.

[0142] The processor 400 is responsible for managing the bus architecture and general processing, while the memory 420 can store the data used by the processor 400 when performing operations.

[0143] This application also provides a readable storage medium storing a program. When executed by a processor, this program implements the various processes of the parameter determination method embodiment and achieves the same technical effect. To avoid repetition, it will not be described again here. The readable storage medium may be, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0144] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0145] The above are preferred embodiments of the present application, it should be pointed out that, for those skilled in the art, without departing from the principles described in the present application, can make several improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A parameter determination method characterized by, The method comprises: determining a first coefficient according to test data of a first test, wherein the first test is a test in which a battery reaches thermal equilibrium under the same initial battery temperature, different ambient temperatures and different coolant temperatures; determining a second coefficient according to test data of a second test, wherein the second test is a test in which a battery reaches thermal equilibrium under the same initial battery temperature, the same coolant temperature and different ambient temperatures; determining a temperature curve for achieving thermal equilibrium of the battery according to the first coefficient, the second coefficient and a predefined thermal equilibrium relationship; determining the shortest time required for the battery to reach thermal equilibrium under different ambient temperatures, and corresponding coolant temperatures and third thermal equilibrium temperatures according to the temperature curve.

2. The method of claim 1, wherein, The test data of the first test comprises a first thermal equilibrium temperature of the battery when the battery reaches thermal equilibrium, an ambient temperature of the first test and a coolant temperature of the first test.

3. The method of claim 2, wherein, The determining of the first coefficient according to the test data of the first test comprises: calculating a first difference between the first thermal equilibrium temperature and an ambient temperature corresponding to the first thermal equilibrium temperature; calculating a second difference between the first thermal equilibrium temperature and a coolant temperature corresponding to the first thermal equilibrium temperature; determining the first coefficient according to the second difference and the first difference.

4. The method of claim 3, wherein, The determining of the first coefficient according to the second difference and the first difference comprises: calculating a first ratio of each second difference to a first difference corresponding to the second difference; fitting a plurality of the first ratios to determine the first coefficient.

5. The method of claim 1, wherein, The test data of the second test comprises a first duration required for the battery to reach thermal equilibrium, a second thermal equilibrium temperature, an initial battery temperature of the second test and an ambient temperature of the second test.

6. The method of claim 5, wherein, The determining of the second coefficient according to the test data of the second test comprises: calculating a third difference between each ambient temperature and the initial battery temperature in the second test; calculating a fourth difference between each ambient temperature and a second thermal equilibrium temperature corresponding to the ambient temperature in the second test; calculating a first average of each third difference and a fourth difference corresponding to the third difference; determining a first temperature coefficient of an ambient temperature on a battery according to each fourth difference and a first duration corresponding to the fourth difference; determining the second coefficient according to the first temperature coefficient and the first average.

7. The method of claim 6, wherein, The determining of the second coefficient according to the first temperature coefficient and the first average comprises: calculating a third ratio of the first temperature coefficient to the first average corresponding to the first temperature coefficient; fitting a plurality of the third ratios to determine the second coefficient.

8. The method according to any one of claims 1 to 7, characterized in that, The determining of the temperature curve for achieving thermal equilibrium of the battery according to the first coefficient, the second coefficient and a predefined thermal equilibrium relationship comprises: determining a third coefficient according to the first coefficient and the second coefficient, wherein the third coefficient is a ratio of a second temperature coefficient to a fifth difference, the second temperature coefficient is a temperature coefficient of a coolant temperature on a battery, and the fifth difference is a difference between a real-time temperature of the battery and the coolant temperature. The temperature curve is determined according to the second coefficient, the third coefficient and the heat balance relationship.

9. The method of claim 8, wherein, The relationship corresponding to the temperature curve is: ; wherein, represents the calculated temperature of the battery at k+1 time, represents the second coefficient, represents the third coefficient, represents the temperature of the battery at k time, represents the time interval between k+1 time and k time, represents the ambient temperature, represents the coolant temperature.

10. A parameter determination apparatus characterized by comprising: The method comprises: a first determining module configured to determine a first coefficient according to test data of a first test, wherein the first test is a test in which a battery reaches a heat balance at a same initial battery temperature, different ambient temperatures and different coolant temperatures; a second determining module configured to determine a second coefficient according to test data of a second test, wherein the second test is a test in which the battery reaches the heat balance at the same initial battery temperature, a same coolant temperature and different ambient temperatures; a third determining module configured to determine a temperature curve for achieving the heat balance of the battery according to the first coefficient, the second coefficient and a predefined heat balance relationship; a fourth determining module configured to determine, according to the temperature curve, a shortest time required for the battery to reach the heat balance at different ambient temperatures, and corresponding coolant temperatures and third heat balance temperatures.

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