CN113378379A - Lithium battery thermal management design method, system and terminal based on critical heat exchange coefficient - Google Patents
Lithium battery thermal management design method, system and terminal based on critical heat exchange coefficient Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 57
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 45
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 45
- 238000013461 design Methods 0.000 title claims abstract description 30
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- 230000017525 heat dissipation Effects 0.000 claims description 34
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- 238000007599 discharging Methods 0.000 claims description 8
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 7
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Abstract
The invention belongs to the technical field of lithium battery thermal management, and discloses a lithium battery thermal management design method, system and terminal based on a critical heat exchange coefficientcr(ii) a Establishing a set of numerical solving method for determining the critical heat exchange coefficient; based on the analysis of the influence factors, h is obtainedcrThe fitting formula of (1). The invention provides and quantitatively solves a design concept based on a critical heat exchange coefficient to design the thermal management of the lithium batteryThe system analyzes the quantitative influence of various working condition factors on the critical heat exchange coefficient. On the basis of a design concept, an operation strategy based on intervention time is provided, and the temperature of the battery is effectively controlled to be in a safe range; the invention innovatively provides the critical heat exchange coefficient hcrAnd develops a set of numerical solving method for determining the critical heat exchange coefficient, namely the critical heat exchange coefficient hcrThe method can effectively guide the thermal safety operation of the system, and has good guiding significance for parameter selection and optimization design of the thermal management system.
Description
Technical Field
The invention belongs to the technical field of lithium battery thermal management, and particularly relates to a lithium battery thermal management design method, system and terminal based on a critical heat exchange coefficient.
Background
At present, lithium batteries become the most widely used power batteries due to the advantages of large capacity, high energy density, small self-discharge and the like. When the temperature of the battery is too high, the discharge of the battery is accelerated, which causes a series of dangers such as overheating, fire, explosion, etc., so that a more advanced and reasonable thermal management system needs to be designed to keep the temperature of the battery within an ideal working temperature range.
In order to solve the problem of rapid heat generation of the battery under extreme working conditions, a common method is to adopt a heat dissipation system with high conductivity to improve the heat dissipation capacity, such as heat pipes, phase-change materials, heat pipe-phase-change material coupling and the like, and the like (Nanchang university, a vehicle cylindrical lithium battery module based on heat pipes and liquid-cooling coupling heat dissipation: CN202011502669.2[ P ] 2021-02-12.) invents a heat management system with heat pipes and liquid-cooling coupling heat dissipation. But with the attendant increase in system complexity and energy consumption. When designing a thermal management system, researchers generally perform a series of tests on the system, such as a rate test, a test in a high-temperature environment, and the like, and then perform an optimization design, so that the test period is long, and the resource consumption is large. Battery thermal management under extreme operating conditions is fraught with challenges.
In view of the nature of thermal management, it is ensured that the heat dissipation system can remove the generated heat in time, and the rapid rise of the battery temperature can be avoided. Semenov (Semenov n.n. sound systems in Chemical Kinetics and reaction, Volume 2[ M ]. Princeton University Press:2017-03-14.) proposes a tool that can represent the interaction between heat generation and heat dissipation, which compares the rate of heat generation and dissipation as a function of cell temperature. The SEMENOV diagram can be used for analyzing the influence of the change of the convective heat transfer coefficient on the thermal runaway starting process and predicting the safe region of the thermal design space. The concept of SEMENOV diagram, namely battery heat generation and heat dissipation matching, can be extended to battery thermal management, but past related studies are only qualitative analyses and lack quantitative studies.
Through the above analysis, the problems and defects of the prior art are as follows:
the design concept of the lithium battery thermal management system under the extreme working condition lacks a clear theoretical guidance, so that the system is excessively redundant, and the reliability and the economy of the system are reduced. In addition, if the designed thermal management system has insufficient heat dissipation performance, the safety performance of the battery is also reduced.
The difficulty in solving the above problems and defects is:
and a proper quantitative analysis method is lacked to discuss the relation between the actual heat dissipation requirement and the actual working condition. The invention provides a design method of a thermal management system based on a critical heat exchange coefficient in an innovative way by applying a heat generation and heat dissipation balance basis. Wherein h iscrThe method is a function depending on actual operation condition parameters, and can quickly judge the balance condition of heat generation and heat dissipation of the battery by combining the actual parameters.
The significance of solving the problems and the defects is as follows:
and calculating a critical heat exchange coefficient according to actual operating condition parameters, and providing a design basis for the design of the heat dissipation performance of the heat management system. On the basis of temperature rise risk judgment based on the critical heat exchange coefficient, the method can guide the battery system to take auxiliary intervention measures.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a lithium battery thermal management design method, a lithium battery thermal management design system and a lithium battery thermal management terminal based on a critical heat exchange coefficient.
The invention is realized in such a way that a lithium battery thermal management design method based on a critical heat exchange coefficient comprises the following steps:
step one, defining critical heat exchange coefficient hcr(ii) a Establishing a set of numerical solving method for determining the critical heat exchange coefficient;
step two, based on the analysis of the influence factors, h is obtainedcrA fitting function formula about actual operating condition parameters;
step three, based on hcrPre-judging the unexpected temperature rise risk of the battery; intervention measures are taken on the battery within the intervention time.
Further, in the step one, the critical heat exchange coefficient hcrIn order to ensure that the temperature of the lithium battery is in the minimum threshold value of the heat exchange coefficient in an ideal working range, under the extreme working condition of high-rate discharge, the heat generation process and the heat dissipation process of the battery are comprehensively considered, and the change of the highest temperature of the battery along with time mainly has four conditions of case 1, case 2, case 3 and case 4:
in case 1, the heat dissipation capacity of the lithium ion battery heat dissipation system is far greater than the self-generated heat capacity of the battery, and the highest temperature of the lithium ion battery can be well controlled within a threshold range;
when case 2 is adopted, the highest temperature of the lithium battery is just controlled to be TcrAt a critical state;
in case 3, the equivalent heat dissipation coefficient of the system is lower than that of case 2, and the maximum temperature exceeds TcrBut the temperature rise can be slowly controlled;
For a given battery, given TcrH corresponding to case 2 is determined as hcr。
Further, in the first step, the establishing a set of numerical solving method for determining the critical heat transfer coefficient specifically includes:
the first step is as follows: selecting working condition data parameters: initial temperature T of battery0And the heat exchange ambient temperature TabDischarge rate Crate；
The second step is that: designing the equivalent heat exchange coefficient of the heat management system to be h, and obtaining the change of the battery temperature along with the time by utilizing a temperature acquisition device or numerical simulation;
the third step: determining the maximum safe temperature T according to the actual situation and the engineering requirementcrDetecting whether the temperature condition of the battery in the discharging process meets the condition that the battery is always at the safe temperature T of the batterycrIf not, increasing h by the user-defined micro amount dh, and returning to the second step;
the fourth step: detecting whether the temperature condition of the battery is enough to self-define a tiny amount dT close to the safe temperature T of the battery during the discharging processcrIf not, the h is properly reduced by the user-defined micro-quantity dh, the second step is returned, and T is gradually cycled to enable T to be gradually cycledmaxApproximation TcrWhen T ismaxInfinite proximity to TcrThe h output at this time is hcr。
Further, in the second step, h is obtained based on the analysis of the influence factorscrThe fitting function formula for the actual operating condition parameters includes:
(1) heat exchange ambient temperature TabDischarge rate CrateIs hcrTaking T as a sensitive factorabH at a certain valuecrIs a reference hcrfAnd changing the discharge multiplying power, and calculating to obtain the critical heat exchange coefficients under different multiplying powers. Fitting to obtain a functional relation showing the critical heat exchange coefficient and the discharge rate: h iscrf＝g1(Crate)。
(2) Changing TabCalculating to obtain different TabH of timecrDefinition of dimensionless
Is simulated to obtain
And TabAnd fitting, the functional form being:
further, the actual operation condition parameters and hcrThe relationship of (1) includes:
synthesis g1Function sum g2Function, get the indication hcrAnd Tab、CrateFunctional relationship of the relationship: h iscr＝f(Tab， Crate)。
Further, in step three, the base is hcrThe pre-judging of the risk of unexpected temperature rise of the battery comprises the following steps:
comparing the equivalent heat exchange coefficient h of the heat dissipation system with the corresponding h of the actual working conditioncrThe magnitude relationship of (1); critical heat exchange coefficient h when actual heat radiation condition h of system is less than actual working conditioncrJudging that the battery has the risk of unexpected temperature rise; when the actual heat dissipation condition h of the system is more than or equal to the critical heat exchange coefficient h under the actual working conditioncrAnd judging that the battery has no risk of unexpected temperature rise.
Further, in step three, the taking of the intervention measure on the battery within the intervention time includes:
(1) determining the working condition data parameters at the moment, obtaining the change of the battery temperature along with the time by utilizing a temperature acquisition device or numerical simulation, and obtaining the maximum temperature T of the battery when the maximum temperature T of the battery is reachedmaxEqual to or infinitely close to TcrThen, recording the discharge time at the moment, wherein the time period is the intervention time tauintv。
(2) The battery rate reduction operation is controlled through a thermal management system, namely, the charging and discharging rate C is reduced in the intervention timerate(ii) a Selection of discharge multiplying factor CrateReduced value according to hcrIs fitted with a function hcr＝f(Tab，Crate) Calculating h under this conditioncrWhen the multiplying power is reduced and still greater than the equivalent heat exchange coefficient h of the battery heat management system, the numerical value of the multiplying power is continuously reduced until h is greater than hcr。
The invention also aims to provide a lithium battery thermal management system based on the critical heat exchange coefficient, which implements the lithium battery thermal management design method based on the critical heat exchange coefficient.
The invention also aims to provide a lithium battery related to the lithium battery thermal management design method based on the critical heat exchange coefficient.
Another object of the present invention is to provide a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the processor executes the method for designing the thermal management of a lithium battery based on a critical heat transfer coefficient.
Another object of the present invention is to provide an information data processing terminal including a memory and a processor, the memory storing a computer program, the computer program, when executed by the processor, causing the processor to execute the steps of:
step one, defining critical heat exchange coefficient hcr(ii) a Establishing a set of numerical solving method for determining the critical heat exchange coefficient;
step two, based on the analysis of the influence factors, h is obtainedcrA fitting function formula about actual operating condition parameters;
step three, based on hcrPre-judging the unexpected temperature rise risk of the battery; intervention measures are taken on the battery within the intervention time.
By combining all the technical schemes, the invention has the advantages and positive effects that:
the invention innovatively provides a heat exchange coefficient h based on criticalcrThe thermal management system design concept of (1). h iscrThe minimum threshold value of the heat exchange coefficient is used for ensuring that the temperature of the lithium battery is in an ideal working range. h iscrCan be applied to quickly determine the balance between heat generation and heat dissipation of the battery. When h is generated>hcrThe system can ensure the safe operation of the battery; when h is generated<hcrThe battery temperature may exceed the ideal operating range, risking rapid temperature rise.
The invention provides a set of method for establishing h based on experiment or numerical simulationcrMethod for calculating a model, h thus establishedcrThe model is a function of actual operating condition parameters.The model has the advantages that the maximum rated working condition parameters of the power battery can be converted into the heat exchange coefficient requirement of the heat management and radiation system, and the design of the heat management system is quantitatively guided.
Critical heat transfer coefficient hcrThe model can also be used for judging the risk of the over-rated working condition, and guides the thermal management system to implement an auxiliary intervention means in effective time aiming at the unexpected temperature rise risk so as to ensure the safe operation of the battery.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained from the drawings without creative efforts.
Fig. 1 is a schematic diagram of matching conditions of heat generation rate and heat dissipation rate of a lithium battery provided by an embodiment of the invention.
FIG. 2 is a block diagram of determining h according to an embodiment of the present inventioncrThe calculation of (1).
FIG. 3 shows the same C provided by the embodiment of the present inventionrate、Tab、T0Graph of the maximum temperature of the lower cell as a function of time.
FIG. 4 is a diagram of h provided by an embodiment of the present inventioncrThe change along with the discharge multiplying power and the heat exchange environment temperature is shown schematically.
FIG. 5 shows different magnifications provided by embodiments of the present invention
And TabSchematic diagram of the relationship of (1).
Fig. 6 is a graph of the temperature change of the battery operated by the power reduction intervention according to the embodiment of the invention.
Fig. 7 is a temperature profile for a battery intervention operating strategy provided by an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Aiming at the problems in the prior art, the invention provides a lithium battery thermal management design method based on a critical heat exchange coefficient, and the invention is described in detail below with reference to the accompanying drawings.
As shown in fig. 1, a lithium battery thermal management design method based on a critical heat transfer coefficient according to an embodiment of the present invention includes:
s101, defining a critical heat exchange coefficient hcr(ii) a Establishing a set of numerical solving method for determining the critical heat exchange coefficient;
s102, obtaining h based on influence factor analysiscrA fitting function formula about actual operating condition parameters;
s103, based on hcrPre-judging the unexpected temperature rise risk of the battery; intervention measures are taken on the battery within the intervention time.
In step S101 in the embodiment of the present invention, under an extreme condition of high-rate discharge, the heat generation process and the heat dissipation process of the battery are considered comprehensively, and there are four main cases of the change of the maximum temperature of the battery with time, as shown in fig. 2. In FIG. 2, T0Represents the initial temperature of the battery; t iscrThe maximum safe temperature (which can be selected according to actual conditions); case 1, case 2, case 3, and case 4 represent four different heat generation and heat dissipation relationships.
In case 1, the heat dissipation capacity of the lithium ion battery heat dissipation system is far greater than the self-generated heat capacity of the battery, and the highest temperature of the lithium ion battery can be well controlled within a threshold range;
when case 2 is adopted, the highest temperature of the lithium battery is just controlled to be TcrAt a critical state;
in case 3, the equivalent heat dissipation coefficient of the system is lower than that of case 2, and the maximum temperature exceeds TcrBut the temperature rise can be slowly controlled;
For a given battery, given TcrH corresponding to case 2 is determined as hcr。hcrThe meaning of (1) is a heat exchange coefficient minimum threshold value capable of ensuring that the temperature of the lithium battery is in an ideal working range.
In step S101 of the embodiment of the present invention, the critical heat transfer coefficient is not a constant value, and h is known from the heat generation and dissipation modelcrAnd Tab(ambient temperature for Heat transfer), T0(initial temperature of Battery) and Crate(discharge multiplying power) is related, the numerical solving process is shown in figure 3, and dT and dh are self-defined tiny quantities. The description of fig. 3 is as follows:
the first step is as follows: selecting working condition data parameters: initial temperature T of battery0And the heat exchange ambient temperature TabDischarge rate Crate；
The second step is that: designing the equivalent heat exchange coefficient of the heat management system to be h, and obtaining the change of the battery temperature along with the time by utilizing a temperature acquisition device or numerical simulation;
the third step: determining the maximum safe temperature T according to the actual situation and the engineering requirementcrDetecting whether the temperature condition of the battery in the discharging process meets the condition that the battery is always at the safe temperature T of the batterycrIf not, increasing h by the user-defined micro amount dh, and returning to the second step;
the fourth step: detecting whether the temperature condition of the battery is enough to self-define a tiny amount dT close to the safe temperature T of the battery during the discharging processcrIf not, the h is properly reduced by the user-defined micro-quantity dh, the second step is returned, and T is gradually cycled to enable T to be gradually cycledmaxApproximation TcrWhen T ismaxInfinite proximity to TcrThe h output at this time is hcr。
In step S102 in the embodiment of the present invention, h is obtained based on the analysis of the influence factorscrFitting function formula related to actual operation condition parameters
The method specifically comprises the following steps:
a. temperature of heat exchange environmentTabDischarge rate CrateIs hcrTaking T as a sensitive factorabH at a certain valuecrIs a reference hcrAnd f, changing the discharge multiplying power, and calculating to obtain the critical heat exchange coefficients under different multiplying powers. Fitting to obtain a functional relation showing the critical heat exchange coefficient and the discharge rate: h iscrf＝g1(Crate)。
b. Changing TabCalculating to obtain different TabH of timecrDefinition of dimensionless
Is simulated to obtain
And TabAnd fitting, the functional form being:
c. synthesis g1Function sum g2Function, get the indication hcrAnd Tab、CrateFunctional relationship of the relationship: h iscr＝f(Tab， Crate、)。
In step S103 in the embodiment of the present invention, the process is based on hcrPredicting the risk of an unexpected temperature increase of the battery
The method specifically comprises the following steps:
comparing the equivalent heat exchange coefficient h of the heat dissipation system with the corresponding h of the actual working conditioncrThe magnitude relationship of (1); critical heat exchange coefficient h when actual heat radiation condition h of system is less than actual working conditioncrJudging that the battery has the risk of unexpected temperature rise; when the actual heat dissipation condition h of the system is more than or equal to the critical heat exchange coefficient h under the actual working conditioncrAnd judging that the battery has no risk of unexpected temperature rise.
In step S103 in the embodiment of the present invention, intervention measures are taken on the battery during the intervention time
The method specifically comprises the following steps:
(1) to determine the timeWorking condition data parameters are obtained by utilizing a temperature acquisition device or numerical simulation to obtain the change of the battery temperature along with time when the maximum temperature T of the battery is reachedmaxEqual to or infinitely close to TcrWhen the current discharge time is recorded, the current discharge time is the intervention time tauintv。
(2) The battery rate reduction operation is controlled through a thermal management system, namely, the charging and discharging rate C is reduced in the intervention timerate(ii) a Selection of discharge multiplying factor CrateReduced value according to hcrIs fitted with a function hcr＝f(Tab，Crate) Calculating h under this conditioncrWhen the multiplying power is reduced and still greater than the equivalent heat exchange coefficient h of the battery heat management system, the numerical value of the multiplying power is continuously reduced until h is greater than hcr。
The technical solution of the present invention will be further described with reference to the following embodiments.
1) Critical equivalent heat transfer coefficient hcrThe numerical solution method of (2):
the following relevant parameters need to be measured or directly given: the size of a 18650 lithium battery is l multiplied by R, and the equivalent radial thermal conductivity coefficient is kT,x(ii) a Axial coefficient of thermal conductivity kT,y(ii) a Density is rhocell(ii) a Specific heat capacity of ccell. Setting the initial temperature to 303.15K and the maximum safe temperature Tcr313.15K (which may vary depending on the situation), the initial SOC value SOC (0) is 1, and the discharge is stopped when the SOC drops to 0.2.
Setting the discharge multiplying power to be 7C and the heat exchange environment temperature TabIs 300K, T0303.15K. And changing different h values to obtain a change curve of the highest temperature of the plurality of batteries along with time. The temperature of the battery can be acquired by a temperature acquisition device or a numerical value. The invention establishes a battery model, and the balance of heat generation and heat dissipation of the lithium battery meets the following formula:
wherein T is the temperature of the battery, K; t iswThe battery outer wall temperature, K; k is a radical ofwIs the coefficient of thermal conductivity of the outer wall, W.m-1·K-1(ii) a l and R represent the length and radius of the battery, respectively; h is the equivalent heat exchange coefficient between the lithium ion battery and the outside world, W.m-2·K-1(ii) a q is the heat generation rate per unit volume of the lithium battery, W.m-3And can be obtained by simulation and actual measurement.
Determining a maximum safe temperature TcrIt was 313.15K. According to the numerical solving flow chart shown in figure 3, the battery temperature under the working condition is found to be ensured to be at TcrThe internal heat exchange coefficient is hcr＝39W·m-2·K-1FIG. 4 shows the variation of the maximum temperature of the battery with time at different h, h<hcrThe maximum temperature is very easy to exceed Tcr；
Setting various working conditions of different heat exchange environment temperatures, discharge multiplying powers and initial temperatures, and solving the critical equivalent heat exchange coefficient h corresponding to the working conditionscrAs shown in fig. 5, the calculation results show that the discharge rate and the heat exchange environment temperature are sensitive factors of the critical heat exchange coefficient;
2) obtained hcrFitting function formula about actual operating condition parameters:
selection of TabH at 293.15KcrIs a reference hcrf. And a curve fitting method is utilized to establish hcrfFunction relation h with discharge ratecrf＝g1(Crate)；
Setting different TabWorking condition of (1), calculating to obtain different TabH of timecrDefinition of dimensionless
Simulation ofTo obtain
And TabThe average trend curve of (1) is shown in figure 6, which shows that under different discharge rates,
and TabWith similar trends, the scatter points are distributed above and below a curve. Method for establishing by curve fitting
And TabIs a function of the mean trend curve of (a):
synthesis g1Function sum g2Function, get the indication hcrAnd Tab、CrateFunctional relationship of the relationship:
in the formula, the coefficient values are shown in the attached table 1.
TABLE 1 hcrValue of fitting equation coefficient
3) Predicting unexpected temperature rise risk:
setting the ambient temperature T of the heat exchangeabThe discharge rate was 300K and 7C. The heat management system h is designed to be 39 W.m-2·K-1According to hcr＝f(Tab，Crate) The fitting function relation of (1) calculates h at that timecrIs 68 W.m-2·K-1Based on the critical heat transfer coefficient hcrThe battery temperature rise risk is pre-judged, namely h is judged<hcrIn this case h<hcr。
4) And (3) intervening and operating:
after the risk that the battery actually exceeds the ideal working temperature range is judged in advance, the intervention time can be calculated according to the actual use condition and the engineering requirement, and intervention measures are carried out on the battery operation in the intervention time, such as reduction of the discharge rate.
Setting the discharge multiplying power to be 7C and the heat exchange environment temperature TabIs 300K, T0303.15K, calculating to obtain the change curve of the battery temperature along with the time through a numerical model, and observing the maximum temperature T of the lithium batterymaxReaches a set temperature TcrWhen T is detected, the discharge time is recorded as the intervention time, and when T is detectedab300K, the intervention time of the lithium battery is 216 s;
the intervention operation scheme is implemented specifically: and controlling the discharge rate of the battery. Calculation 5C, TabH at 300KcrIs 31 W.m-2·K-1At this time h>hcr. And at the intervention time point, selectively reducing the discharge rate to 5C, substituting the data into the model, and solving the change of the battery temperature under the intervention scheme, wherein a temperature curve under a battery intervention operation strategy is shown in figure 7, and the maximum temperature of the lithium battery is reduced by about 3K.
In the description of the present invention, "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.
Claims (9)
1. A lithium battery thermal management design method based on a critical heat exchange coefficient is characterized by comprising the following steps:
step one, defining critical heat exchange coefficient hcr(ii) a Establishing a set of numerical solving method for determining the critical heat exchange coefficient;
step two, based on the analysis of the influence factors, h is obtainedcrA fitting function formula about actual operating condition parameters;
step three, based on hcrPre-judging the unexpected temperature rise risk of the battery; intervention measures are taken on the battery within the intervention time.
2. The critical heat transfer coefficient-based lithium battery thermal management design method of claim 1, wherein in the first step, the critical heat transfer coefficient hcrIn order to ensure that the temperature of the lithium battery is in the minimum threshold value of the heat exchange coefficient in an ideal working range, under the extreme working condition of high-rate discharge, the heat generation process and the heat dissipation process of the battery are comprehensively considered, and the change of the highest temperature of the battery along with time mainly has four conditions of case 1, case 2, case 3 and case 4:
in case 1, the heat dissipation capacity of the lithium ion battery heat dissipation system is far greater than the self-generated heat capacity of the battery, and the highest temperature of the lithium ion battery can be well controlled within a threshold range;
when case 2 is adopted, the highest temperature of the lithium battery is just controlled to be TcrAt a critical state;
in case 3, the equivalent heat dissipation coefficient of the system is lower than that of case 2, and the maximum temperature exceeds TcrBut the temperature rise can be slowly controlled;
case 4, the thermal management system cannot timely carry away the self-generated heat, the battery temperature can rapidly and continuously increase uncontrollably, and at some point,Tmax＝Tcrthis time is defined as the intervention time τintv；
For a given battery, given TcrH corresponding to case 2 is determined as hcr。
3. The critical heat transfer coefficient-based lithium battery thermal management design method of claim 1, wherein in the second step, the establishing a set of numerical solution methods for determining the critical heat transfer coefficient specifically comprises:
the first step is as follows: selecting working condition data parameters: initial temperature T of battery0And the heat exchange ambient temperature TabDischarge rate Crate；
The second step is that: designing the equivalent heat exchange coefficient of the heat management system to be h, and obtaining the change of the battery temperature along with the time by utilizing a temperature acquisition device or numerical simulation;
the third step: determining the maximum safe temperature T according to the actual situation and the engineering requirementcrDetecting whether the temperature condition of the battery in the discharging process meets the condition that the battery is always at the safe temperature T of the batterycrIf not, increasing h by the user-defined micro amount dh, and returning to the second step;
the fourth step: detecting whether the temperature condition of the battery is enough to self-define a tiny amount dT close to the safe temperature T of the battery during the discharging processcrIf not, the h is properly reduced by the user-defined micro-quantity dh, the second step is returned, and T is gradually cycled to enable T to be gradually cycledmaxApproximation TcrWhen T ismaxInfinite proximity to TcrThe h output at this time is hcr。
4. The critical heat transfer coefficient-based lithium battery thermal management design method of claim 1, wherein in the third step, h is obtained based on influence factor analysiscrThe fitting formula of (a) includes:
(1) heat exchange ambient temperature TabDischarge rate CrateIs hcrTaking T as a sensitive factorabH at a certain valuecrIs a reference hcrfChanging discharge multiplying power, calculating to obtain differenceCritical heat transfer coefficient under multiplying power. Fitting to obtain a functional relation showing the critical heat exchange coefficient and the discharge rate: h iscrf＝g1(Crate)。
(2) Changing TabCalculating to obtain different TabH of timecrDefinition of dimensionless
Is simulated to obtain
And TabAnd fitting, the functional form being:
(3) synthesis g1Function sum g2Function, get the indication hcrAnd Tab、CrateFunctional relationship of the relationship: h iscr＝f(Tab，Crate)。
5. The critical heat transfer coefficient-based lithium battery thermal management design method of claim 4, wherein the quantitative solution is
And TabThe relationship of (1) includes:
simulating to obtain the power under each multiplying power
And TabAnd fitting, the functional form being:
6. a lithium battery thermal management system based on the critical heat exchange coefficient is used for implementing the lithium battery thermal management design method based on the critical heat exchange coefficient according to any one of claims 1 to 5.
7. A lithium battery related to the lithium battery thermal management design method based on the critical heat exchange coefficient and according to any one of claims 1 to 5.
8. A computer-readable storage medium storing a computer program, which when executed by a processor, causes the processor to execute the method for designing a thermal management of a lithium battery based on a critical heat transfer coefficient according to any one of claims 1 to 5.
9. An information data processing terminal characterized by comprising a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of:
step one, defining critical heat exchange coefficient hcr(ii) a Establishing a set of numerical solving method for determining the critical heat exchange coefficient;
step two, based on the analysis of the influence factors, h is obtainedcrA fitting function formula about actual operating condition parameters;
step three, based on hcrPre-judging the unexpected temperature rise risk of the battery; intervention measures are taken on the battery within the intervention time.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104569836A (en) * | 2014-12-16 | 2015-04-29 | 北京新能源汽车股份有限公司 | Method and device for measuring heat generation power of batteries in condition of variable current |
| CN107391870A (en) * | 2017-08-02 | 2017-11-24 | 中国科学技术大学 | The computational methods of thermal runaway critical condition |
| CN111460664A (en) * | 2020-04-01 | 2020-07-28 | 吉林大学 | Nonlinear cooling optimization method for new energy automobile power battery |
| US20210104788A1 (en) * | 2019-10-08 | 2021-04-08 | Baidu Usa Llc | Optimal control logic for cooling power in battery thermal management |
-
2021
- 2021-06-08 CN CN202110639563.5A patent/CN113378379B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104569836A (en) * | 2014-12-16 | 2015-04-29 | 北京新能源汽车股份有限公司 | Method and device for measuring heat generation power of batteries in condition of variable current |
| CN107391870A (en) * | 2017-08-02 | 2017-11-24 | 中国科学技术大学 | The computational methods of thermal runaway critical condition |
| US20210104788A1 (en) * | 2019-10-08 | 2021-04-08 | Baidu Usa Llc | Optimal control logic for cooling power in battery thermal management |
| CN111460664A (en) * | 2020-04-01 | 2020-07-28 | 吉林大学 | Nonlinear cooling optimization method for new energy automobile power battery |
Non-Patent Citations (3)
| Title |
|---|
| ALEXANDER BÖRGER等,: "Thermal runaway and thermal runaway propagation in batteries: What do we talk about?", 《JOURNAL OF ENERGY STORAGE》, vol. 24, pages 100649 * |
| KRISHNA SHAH等: "Experimental and theoretical analysis of a method to predict thermal runaway in Li-ion cells", 《JOURNAL OF POWER SOURCE》, vol. 330, pages 167 - 174, XP029743248, DOI: 10.1016/j.jpowsour.2016.08.133 * |
| 王发成等: "车用动力电池组集总参数换热模型", 《兵工学报》, vol. 35, no. 2, pages 145 - 151 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113851760A (en) * | 2021-09-26 | 2021-12-28 | 上汽通用五菱汽车股份有限公司 | Temperature control method of battery system, vehicle and readable storage medium |
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