CN115935845A - Method for optimizing heat preservation and heat insulation performance of battery module, battery module and battery pack - Google Patents
Method for optimizing heat preservation and heat insulation performance of battery module, battery module and battery pack Download PDFInfo
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Abstract
The invention discloses a method for optimizing the heat preservation and heat insulation performance of a battery module, the battery module and a battery pack, which belong to the technical field of batteries for converting chemical energy into electric energy, and comprise the following steps: constructing a three-dimensional entity heat flow simulation model of the battery module; deducing a linear change relation between the total heat flow and the environment temperature difference; determining the linear change relationship between the total heat flow of the battery module after the heat-insulating layer is added and the temperature difference of the environment temperature; analyzing the linear change relation between the heat flow on different paths for realizing thermal resistance balance and the temperature difference of the environment temperature, and determining a thermal resistance matching scheme of a thermal insulation layer required to be added under each heat dissipation path; and constructing a physical model of a thermal resistance and heat transfer network in the battery module, and determining a module temperature difference design index. Based on the equivalent resistance theory and the scheme practice, the invention is applied to the analysis of the temperature field of the power battery pack, the analysis of the heat dissipation path and the application of the equivalent thermal resistance concept by analogy, thereby effectively reducing the dependence degree of the design of the heat preservation scheme on the experience and improving the scientificity of the design.
Description
Technical Field
The invention relates to a method for optimizing heat preservation and heat insulation performance, a battery module and a battery pack, in particular to a method for optimizing heat preservation and heat insulation performance of a battery module, a battery module and a battery pack, and belongs to the technical field of batteries for converting chemical energy into electric energy.
Background
With the social development and progress, the pure electric vehicle is gradually favored by the public and has wide application market. The battery or the battery pack is used as a core power source of the pure electric vehicle, the performance of the battery or the battery pack is easily influenced by temperature, and especially the low-temperature characteristic of the battery seriously influences the reliability of the vehicle in the operation process.
In consideration of the application of the battery pack in a cold environment, the conventional battery pack is mostly provided with an insulating layer, and heat blocking is performed on a possible heat transfer path of the battery so as to reduce heat transfer among the battery core, the battery box body and the outside air. The design and the arrangement of the heat-insulating layer generally comprehensively consider the influences of the heat-insulating material on fire resistance, corrosion resistance, physical and chemical stability, water absorption, heat conductivity and the like, and different heat-insulating materials are selected for combined use aiming at specific installation positions; and (4) finishing simulation calculation and performance analysis of the heat preservation and insulation effect of the selected scheme by combining a three-dimensional heat flow simulation calculation means. However, in terms of the current technology and method, no clear heat preservation index is provided for heat preservation of the battery pack, the design of the heat preservation scheme depends heavily on experience, no scientific explanation is provided for how the scheme reaches the standard, the three-dimensional simulation analysis process is too complicated, the design of the heat preservation scheme is realized as scientifically and accurately as possible to reduce the simulation times, and the temperature uniformity of the battery module is ensured. In addition, most of the existing methods lack consideration of adverse effects caused by overlarge temperature difference between the battery cells.
Disclosure of Invention
The invention aims to provide a method for optimizing the heat preservation and heat insulation performance of a battery module, the battery module and a battery pack, and mainly solves the technical problems that a three-dimensional heat flow simulation model is established, the temperature distribution states among single battery cores and the temperature distribution states of the single battery cores are determined, a feasible heat preservation and heat insulation measure scheme is reversely designed based on the principle of thermal resistance balance design, the uniform temperature distribution of the battery module is realized, the requirement of a heat preservation index is met, the technical problem to be solved is to determine the temperature difference design index of the module by constructing a physical model of a thermal resistance heat transfer network in the battery module, and the reasonable arrangement of the battery cores ensures the temperature uniformity of the module.
The invention provides the following scheme:
compared with the prior art, the invention has the following advantages:
the method comprises the steps of establishing a three-dimensional heat flow simulation model, determining the temperature distribution states among single battery cells and the temperature distribution states of the single battery cells, importing the three-dimensional heat flow simulation model into three-dimensional simulation software to carry out three-dimensional grid configuration, boundary condition setting and three-dimensional heat flow simulation calculation, determining the corresponding function relation of the heat flow of the battery pack under the condition of no heat preservation measures and time through the three-dimensional simulation of the battery pack without heat preservation measures, and deducing the linear change of the temperature difference between the total heat flow of the battery pack without heat preservation measures and the environment temperature.
The invention determines the linear change relation between the total heat flow of the battery pack after the heat preservation layer is added and the temperature difference of the environment temperature according to the heat preservation indexes and the battery module structure, and realizes the design of the heat preservation layer which meets the balance of heat resistance based on the built physical model of the heat resistance and heat transfer network in the three-dimensional direction and the analysis of the heat dissipation path. After the heat preservation scheme is determined, the relationship between the temperature difference inside the module and the number of the series-parallel monomer sections inside the module is obtained according to the temperature uniformity calculation result and the equivalent thermal resistance theoretical analysis, so that the number of the battery cores in the module can be reasonably arranged, and the temperature difference among the monomer battery cores can be reduced.
The invention provides a scientific and efficient thermal resistance modeling method capable of aiming at the equivalence of the inside of a three-dimensional solid battery pack and a battery pack box body with the outside air based on the principle of thermal resistance equivalence and equilibrium design, compared with the prior art, the invention does not carry out the coupling simulation optimization of the three-dimensional heat flow of the battery pack, the related efficiency of a thermal insulation scheme is improved, the simulation workload is reduced, the optimized battery module and the optimized battery pack can be applied to a whole vehicle, the influence of the design of an external thermal insulation layer of the module and the arrangement of electric cores on the temperature uniformity of the whole module is comprehensively considered in the design process, and the invention is different from the structural design and effect measurement standard of the lithium ion battery pack in the prior art. Based on the equivalent resistance theory and the scheme practice, the invention is applied to the analysis of the temperature field of the power battery pack by analogy, the analysis of the heat dissipation path and the application of the equivalent thermal resistance concept effectively reduce the dependence degree of the design of the heat preservation scheme on the experience, and improve the scientificity of the design.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart of a method for optimizing the thermal insulation performance of a battery module based on equivalent and balanced design of thermal resistance in the embodiment of the invention.
Fig. 2 is a schematic view of the main structure of the battery pack.
Fig. 3 is a schematic structural view of the battery module.
FIG. 4 is a graph of heat flux versus time with and without incubation.
FIG. 5 is a diagram showing the relationship between heat flux and temperature difference with and without heat preservation.
FIG. 6 is a thermal resistance and heat transfer model corresponding to different heat dissipation paths under the heat preservation measure.
Fig. 7 is a heat dissipation path analysis diagram.
FIG. 8 is a graph of heat flux through the top cover of the module as a function of temperature difference for a balanced design of thermal resistance.
FIG. 9 is an equivalent thermal resistance model of 1/2 cell in the thickness direction inside the module.
Fig. 10 is a schematic diagram of a system for optimizing the thermal insulation performance of a battery module based on equivalent and balanced design of thermal resistance according to an embodiment of the present invention.
Fig. 11 is a flowchart of a method in a specific application scenario according to an embodiment of the present invention.
Fig. 12 is a schematic structural diagram of an electronic apparatus.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Those skilled in the art can understand that "battery pack" has the same meaning as "battery module" and "module" in the embodiments of the present invention, and belongs to different names of the same concept.
The embodiment of the invention as shown in fig. 1 is a method for optimizing the heat preservation and insulation performance of a battery module based on equivalent and balanced design of thermal resistance:
step S1: constructing a three-dimensional entity heat flow simulation model of the vehicle power battery module under the condition of no heat preservation;
specifically, the method for constructing the three-dimensional solid heat flow simulation model of the vehicle power battery module under the condition of no heat preservation specifically comprises the following steps: constructing a three-dimensional entity heat flow simulation model of the battery module and the box body thereof, and carrying out three-dimensional grid configuration, boundary condition setting and heat flow simulation calculation;
as illustrated in fig. 2 and 3: the simplified battery pack structure model comprises: the battery pack comprises a battery pack box upper cover 1, a battery module 2, a battery pack box lower cover 3, an aluminum plate 4, a module upper shell 5, an electric core and heat insulation glue 6, a module end plate 7, a module side plate 8, a module lower shell 9 (the module upper shell and the module lower shell and the end side plate are module outer frames wrapping the electric core), an electric core, a heat insulation layer and an air domain in the box (the rest parts in the box are considered to be air filling), wherein the size of the battery pack box is 1.95 × 1.36 × 0.125m; electric core is neatly arranged along thickness direction in the module, and the adhesion heat-insulating glue between adjacent electric core: thickness of cell heat insulation glue: 1mm, thermal conductivity: 0.04W/(m.K); cell thermal conductivity (XYZ direction): 3.2W/(mK), 15W/(mK), and 15W/(mK). And importing the three-dimensional model into three-dimensional simulation software to carry out three-dimensional grid configuration, boundary condition setting and three-dimensional heat flow simulation calculation.
Step S2: deducing a linear change relation between the total heat flow of the non-heat-preservation battery module and the environmental temperature difference;
specifically, the derivation of the linear change relationship between the total heat flow of the non-thermal insulation battery module and the ambient temperature difference specifically includes: extracting a corresponding function relation between the total heat flow and the time of the heat-insulation-free battery module, and deducing a linear change relation between the total heat flow of the heat-insulation-free battery module and the ambient temperature difference according to the heat dissipation capacity of the battery module under the time history;
as illustrated in fig. 4 and 5: the three-dimensional simulation result is extracted to obtain the corresponding function relation of the total heat flow and the time of the heat-insulation-free battery module as
And the temperature difference-time relation y = T (T), and deducing the linear change relation between the total heat flow of the battery module and the temperature difference of the environment temperature->
In the formula: />
t is time and R is the total equivalent thermal resistance in the heat flow direction.
And step S3: determining the linear change relationship between the total heat flow of the battery module after the thermal insulation layer is added and the temperature difference of the environment temperature;
specifically, according to the linear change relationship of the total heat flow of the battery pack and the temperature difference of the environment temperature deduced in the step S2, the linear change relationship of the total heat flow of the battery module and the temperature difference of the environment temperature after the heat preservation layer is added is determined by combining the provided heat preservation index of the battery pack and the actual structure size of the battery module;
the following are exemplary: according to the corresponding functional relation of the total heat flow and the time and the corresponding functional relation of the total heat flow and the temperature difference, in combination with the heat conduction theory,can preliminarily and qualitatively determine the corresponding function relationship between the total heat flow and the time after the heat-insulating layer is added
Similarly, the corresponding function relationship between the total heat flow and the temperature difference after the heat-insulating layer is added is preliminarily and qualitatively determined to meet the requirement
(in the formula, is selected as>
) Wherein R' is the total equivalent thermal resistance after the insulating layer is added.
Illustratively, the heat preservation index is an average temperature drop/rise rate, and the heat preservation index and the actual structural size of the battery module are determined at the moment t 0 Battery module temperature T reached m The specific heat capacity c, mass m and temperature T of the module m Initial temperature T of the module n Substituting the formula Q = cm (T) n -T m ) In (1), find t 0 The total heat dissipating capacity Q of the heat dissipating process in time.
As illustrated in fig. 5, the initial time: the temperature of the battery pack is 25 ℃, the constant temperature of the external environment is-30 ℃, and the temperature difference between the external environment and the module is 55 ℃. Under the condition of no heat preservation: the temperature of the module at the time of 12h is-19 DEG C
′
Temperature difference delta T with external environment 1 Is 11 ℃; temperature change of module Δ T 1 At 44 ℃, substituting the module mass m, the module specific heat capacity c and the module temperature change delta T 'into a formula Q = cm delta T', and determining the total heat dissipation Q of the module without heat preservation 1 。
The heat preservation index is as follows: the temperature drop rate is not more than 3 ℃/h, and the heat dissipation condition is calculated based on the heat preservation index: at t 0 The temperature of the module is-11 ℃ when the time is not less than 12h, and the temperature difference delta T between the module and the external environment 2 At 19 ℃ and die set temperature variation
′
ΔT 2 At 36 ℃, obtaining the total heat dissipation of the module under the design meeting the heat preservation index according to the formula Q = cm delta TQuantity Q 2 。
Further according to the total heat dissipation capacity of the module under the conditions of no heat preservation and heat preservation, the difference value delta Q = Q of the total heat dissipation capacity can be determined 1 -Q 2 The two straight lines respectively represent the corresponding function relationship of heat flow and temperature difference under the conditions of no heat preservation and heat preservation: y = KX and Y = K ′ X, wherein the value of K is determined, K ′ Unknown: the total heat dissipation difference Δ Q is expressed as the area of the shaded portion in the figure by the heat flow-temperature difference function integral: the temperature difference change is reduced from 55 ℃ to 11 ℃ under the condition of no heat preservation, the temperature difference change is reduced from 55 ℃ to 19 ℃ under the condition of heat preservation, delta Q = A1-A2, and therefore the coefficient k of the corresponding function relation between the total heat flow and the temperature difference after the heat preservation layer is added is determined ′ 。
And step S4: analyzing the linear variation relation between the heat flow on different heat dissipation paths for realizing thermal resistance balance and the temperature difference of the environment temperature, and determining a thermal resistance matching scheme of a thermal insulation layer to be added under each heat dissipation path;
specifically, a thermal resistance heat transfer network physical model of the battery module in the three-dimensional direction is established, a heat dissipation path of the battery module with the thermal insulation layer added is determined, a thermal resistance heat transfer physical model of the battery module in the three-dimensional direction is established, a heat dissipation path of the battery module with the thermal insulation layer added is determined, and a heat flow-temperature difference linear relation coefficient k 'of each heat dissipation path' x All equal to the equivalent thermal resistance R on the heat dissipation path x Correlation, i.e. coefficient of linear relationship k' x All with equivalent thermal resistance R on the heat dissipation path x Have a correlation relationship between them. After the equivalent thermal resistance on each heat dissipation path is determined by the heat transfer model, the linear change relationship between the thermal flow on different paths for realizing thermal resistance balance and the environmental temperature difference is analyzed according to the linear change relationship between the total thermal flow of the battery module after the heat preservation layer is added and the environmental temperature difference, so that the thermal resistance matching scheme of the heat preservation and heat insulation layer required to be added under each heat dissipation path is determined, and then the specific heat preservation design scheme is determined according to engineering practice and by combining with the optional heat preservation material.
As illustrated in FIG. 6, a thermal resistance network model after adding an insulating layer is established by using a thermal resistance equivalent principle, and comprises a first thermal resistance R 1 Second thermal resistance R 2 A third thermal resistance R 3 Fourth thermal resistance R 4 Fifth thermal resistance R 5 Sixth thermal resistance R 6 Seventh thermal resistance R 7 Eighth thermal resistance R 8 Ninth thermal resistance R 9 Tenth thermal resistance R 10 Eleventh thermal resistance R 11 Twelfth thermal resistance R 12 First thermal resistance R 1 To twelfth thermal resistance R 12 Corresponding to the situation: the thermal resistance of the upper box cover, the thermal resistance of air in the box body, the thermal resistance of the first heat-insulating layer, the thermal resistance of the module in the upper shell direction, the thermal resistance of the module in the lower shell direction, the thermal resistance of the third heat-insulating layer, the thermal resistance of the box body lower cover, the thermal resistance of an aluminum plate, the thermal resistance of the module side plate end plate direction, the thermal resistance of the second heat-insulating layer, the thermal resistance of air in the box body and the thermal resistance of the lower box cover.
Thermal resistance is the resistance that heat encounters in a heat flow path and reflects the magnitude of the media or the ability of the media to transfer heat. The greater the thermal resistance, the less heat transfer capability. The thermal resistance indicates the temperature rise caused by 1W of heat flow, and the unit is ℃/W or K/W. Therefore, the temperature rise on the heat transfer path can be obtained by multiplying the thermal power consumption by the thermal resistance.
Specifically, the embodiment of the present invention can compare the principle of stacking series resistors in electricity, and has the same rule in heat, that is, in a series heat transfer process, the total thermal resistance of each series link is equal to the sum of the thermal resistances of each series link, where the unit thermal resistance:
in the formula: r is the thermal resistance of the unit structure, K/W;
a-heat flow area per unit structure, unit is m 2 ；
L is the thickness of the unit structure in the heat flow direction, and the unit is m;
lambda is the thermal conductivity of the unit structure material, with the unit being W/(m.K);
ΣR＝R 1 +R 2 +······+R n
in the formula: r 1 ，R 2 ……R n -the thermal resistance of the layers of objects in series,the unit is K/W;
Σ R-equivalent thermal resistance on the heat dissipation path, unit is K/W;
as illustrated in fig. 7, the battery module is divided into 3 heat dissipation paths after the insulating layer is added, and the heat dissipation paths are respectively: the heat is radiated through the upper shell of the module, through the lower shell of the module and through the end plate side plate of the end plate of the shell of the module, and the linear relation coefficient of the total heat flow and the temperature difference is the sum of the linear relation coefficient k of the heat flow and the temperature difference of each heat radiation path. In this embodiment, the battery module includes: casing, module casing curb plate end plate, module casing down on the module, the outer heat preservation of module casing includes: first heat preservation, second heat preservation, third heat preservation have the inside air of box in electric core, heat preservation and box, still include: the upper box cover, the lower box cover and the aluminum plate exchange heat with the external environment through the heat dissipation path.
The heat flow in the built thermal resistance heat transfer model is satisfied
Equivalent thermal resistance R 'on each heat transfer path' x R 'is satisfied' x =Σr, the thermal resistance equalization design is realized, that is:
Σk′ x ＝k′
R′ 1 ＝R′ 2 ＝…R′ x (x＝1,2,3……)
wherein, k' x 、R′ x Respectively representing the linear relation coefficient and equivalent thermal resistance of different heat dissipation paths,
the heat flow in the heat transfer model without heat preservation.
For example, taking heat dissipation through the upper case of the battery module as an example:
in the formula: delta T is the temperature difference between the module temperature and the external environment, DEG C;
A 1 m is the heat transfer area in the heat flow direction of the module 2 ；
L 1 The thickness of the upper cover of the box body is m;
L 3 the total thickness m of the heat-insulating layer in the heat flow direction;
L 4 is the thickness of the upper shell of the module, m;
λ 1 the heat conductivity coefficient of the upper cover of the box body, W/(m DEG C);
λ 3 thermal conductivity of the thermal insulation material, W/(m.DEG C);
λ 4 the coefficient of thermal conductivity of the upper housing of the module, W/(m DEG C);
h is the convective heat transfer coefficient of air in the box body, W/(m) 2 ·℃)。
As illustrated in fig. 8, the thickness of the insulation layer is finally determined, and the equivalent thermal resistance R on each heat dissipation path is determined ′ The size of the module is obtained to obtain the corresponding function relation of heat flow and temperature difference of the heat dissipation through the upper cover of the module
(in the formula, is selected as>
) The relationship between the heat flow and the temperature difference on other paths also meets the above formula, the thermal insulation layer thermal resistance balance design is realized, the abscissa in the figure is the temperature difference/DEG C, and the ordinate is the heat flux/W-heat flux, which is also called heat flux density, heat flux and heat flow, and refers to the heat energy passing through the unit area in unit time and is a vector with directionality.
Step S5: and according to the anisotropy of the heat conduction of the battery core, constructing a physical model of a thermal resistance and heat transfer network in the battery module, and determining a module temperature difference design index.
After the insulating layer is designed on the six external surfaces of the battery module, the requirement on the temperature difference between the battery cores by the module is high due to the fact that the thermal conductivity of the battery monomer is anisotropic, the temperature gradient trends of the battery module in the X direction, the Y direction and the Z direction are consistent, and heat transfer in all directions is uniform.
As shown in fig. 9, considering that the thermal conduction between the cells has anisotropy, in order to ensure that the temperature difference between the cells in the module is small, a thermal resistance heat transfer model is built according to the thermal resistance equivalent principle and the fourier law, and the corresponding relationship between the maximum temperature difference of the module cell and the equivalent thermal resistance in the thickness direction is obtained through numerical simulation. In the thermal resistance heat transfer model, T A 、T 4 Respectively the temperature of the end point and the central point, A is the heat conduction area of the cell in the heat flow direction, namely the thickness direction, lambda is the heat conduction coefficient of the unit structure material, and R x Is a single cell thermal resistance R cell With a single-sided heat-insulating glue R glue Equivalent thermal resistance, battery module heat dissipation have symmetry, and the thermal resistance model only needs simulation 1/2's electric core module to confirm electric core number n and the biggest difference in temperature T of arranging A -T B Determining the design index of the module temperature difference.
For the method steps disclosed in the above embodiments, the method steps are expressed as a series of action combinations for simplicity of description, but those skilled in the art should understand that the embodiments are not limited by the described action sequences, because some steps can be performed in other sequences or simultaneously according to the embodiments of the present invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no particular act is required to implement the invention.
As shown in fig. 10, the system for optimizing the thermal insulation performance of a battery module based on equivalent and balanced thermal resistance design in the embodiment of the present invention specifically includes:
the three-dimensional solid heat flow simulation model building module is used for building a three-dimensional solid heat flow simulation model of the vehicle power battery module under the condition of no heat preservation;
the non-heat-preservation battery module heat flow change relation module is used for deducing a linear change relation between the total heat flow of the non-heat-preservation battery module and the ambient temperature difference;
the thermal insulation battery module heat flow change relation module is used for determining the linear change relation between the total heat flow of the battery module after the thermal insulation layer is added and the temperature difference of the environment temperature;
the thermal flow and environment temperature difference change relation analysis module is used for analyzing the linear change relation between the thermal flow and the environment temperature difference on different paths for realizing thermal resistance balance and determining a thermal resistance matching scheme of a thermal insulation layer to be added under each heat dissipation path;
and the internal thermal resistance and heat transfer network physical model building module is used for building a battery module internal thermal resistance and heat transfer network physical model according to the anisotropy of heat conduction of the battery core and determining module temperature difference design indexes.
It should be noted that, although only some basic functional modules are disclosed in the embodiments of the present invention, the composition of the present system is not limited to the above basic functional modules, and on the contrary, the present embodiment is intended to mean that: on the basis of the basic functional modules, a person skilled in the art can combine the prior art to add one or more functional modules arbitrarily to form an infinite number of embodiments or technical solutions, that is, the present system is open rather than closed, and the protection scope of the present invention claims should not be considered to be limited to the disclosed basic functional modules because the present embodiment discloses only individual basic functional modules. Meanwhile, for convenience of description, the above devices are described as being divided into various units and modules by functions, respectively. Of course, the functions of the units and modules may be implemented in one or more software and/or hardware when implementing the invention.
The embodiments of the system described above are merely illustrative, for example: the functional modules, units, subsystems, and the like in the system may or may not be physically separated, or may not be physical units, that is, may be located in the same place, or may be distributed on a plurality of different systems and subsystems or modules thereof. Those skilled in the art can select some or all of the functional modules, units or subsystems according to actual needs to realize the purpose of the embodiments, and those skilled in the art can understand and implement the above situations without creative efforts.
As shown in fig. 11, the method flow of the embodiment of the present invention in a specific application scenario specifically includes:
the method comprises the following steps: the vehicle power battery pack without the heat preservation condition is provided, a three-dimensional entity heat flow simulation model of the battery pack and a box body of the battery pack is built, and three-dimensional grid configuration, boundary condition setting and heat flow simulation calculation are carried out.
Step two: and (4) extracting a corresponding function relation of the heat flow and the time of the battery pack without heat preservation according to the three-dimensional simulation result in the step one, and deducing a linear change relation between the total heat flow of the battery pack without heat preservation and the temperature difference of the environment temperature according to the heat dissipation capacity of the battery pack under the time history.
Step three: and D, determining the linear change relation between the total heat flow of the battery pack and the ambient temperature difference after the heat insulation layer is added according to the linear change relation between the total heat flow of the battery pack and the ambient temperature difference deduced in the step two and by combining the proposed heat insulation index of the battery pack and the actual structure size of the battery module.
Step four: and constructing a thermal resistance heat transfer network physical model of the battery pack in the three-dimensional direction, simultaneously determining the heat dissipation paths of the battery pack after adding the thermal insulation layer, resolving the linear variation relation between the heat flow on different paths and the ambient temperature difference for realizing thermal resistance balance after determining the equivalent thermal resistance on each heat dissipation path by the heat transfer model according to the linear relation determined in the third step, further determining a thermal resistance matching scheme of the thermal insulation layer to be added under each heat dissipation path, and determining a specific thermal insulation design scheme according to engineering practice and by combining with an optional thermal insulation material.
Step five: on the basis of the heat preservation design, a physical model of a thermal resistance and heat transfer network in the battery module is constructed according to the anisotropy of the heat conduction of the battery core, and a module temperature difference design index, namely the relation between the serial-parallel connection section number in the module and the maximum temperature difference, is determined.
As shown in fig. 12, the embodiment of the present invention further discloses a method for optimizing the thermal insulation performance of a battery module, an electronic device, a storage medium, and a battery pack corresponding to the battery module:
an electronic device, comprising: the system comprises a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory complete mutual communication through the communication bus; the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for optimizing the thermal insulation performance of the battery module.
A computer-readable storage medium storing a computer program executable by an electronic device, the computer program, when run on the electronic device, causing the electronic device to perform the steps of a battery module thermal insulation performance optimization method.
A battery module specifically includes: an electric core; the outer frame is used for wrapping the battery cell;
the battery module is subjected to heat preservation and heat insulation performance optimization by adopting a heat preservation and heat insulation performance optimization method based on equivalent and balanced design of thermal resistance.
A battery pack comprises a battery module.
A processor that runs a program, and when the program is run, performs the steps of the battery module thermal insulation performance optimization method with respect to data output from the electronic device;
and a storage medium for storing a program that, when executed, performs the steps of the method for optimizing the heat insulating performance of the battery module with respect to data output from the electronic device.
It will be understood by those skilled in the art that all or part of the steps carried by the method implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and the program, when executed, includes one or a combination of the steps of the method embodiments.
The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
Moreover, those skilled in the art will appreciate that although some embodiments described herein include some features included in other embodiments, not others, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, any of the embodiments claimed in the claims can be used in any combination.
In the description herein, references to the description of "one embodiment," "an example," "a specific example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination of technical solutions should not be considered to exist, and is not within the protection scope of the present invention.
In addition, the functional modules in the embodiments of the present invention may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive. Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features. Like reference numerals refer to like elements throughout the specification.
Those skilled in the art will appreciate that the modules in the device in an embodiment may be adaptively changed and disposed in one or more devices different from the embodiment. The modules or units or components of the embodiments may be combined into one module or unit or component, and furthermore they may be divided into a plurality of sub-modules or sub-units or sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (16)
1. A method for optimizing the heat preservation and heat insulation performance of a battery module based on equivalent and balanced design of thermal resistance is characterized by comprising the following steps of:
constructing a three-dimensional entity heat flow simulation model of the vehicle power battery module under the condition of no heat preservation;
deducing a linear change relation between the total heat flow of the battery module without heat insulation and the temperature difference of the environment temperature;
determining the linear change relationship between the total heat flow of the battery module after the thermal insulation layer is added and the temperature difference of the environment temperature;
analyzing the linear variation relation between the heat flow on different heat dissipation paths for realizing thermal resistance balance and the temperature difference of the environment temperature, and determining a thermal resistance matching scheme of a thermal insulation layer required to be added under each heat dissipation path;
and according to the anisotropy of the heat conduction of the battery core, constructing a physical model of a thermal resistance and heat transfer network in the battery module, and determining a module temperature difference design index.
2. The thermal resistance equivalence and balance design-based battery module thermal insulation performance optimization method according to claim 1, wherein the method for constructing the three-dimensional solid heat flow simulation model of the vehicle power battery module under the condition of no thermal insulation specifically comprises the following steps: constructing a three-dimensional entity heat flow simulation model of the battery module and the box body thereof, and carrying out three-dimensional grid configuration, boundary condition setting and heat flow simulation calculation;
the method for deducing the linear change relationship between the total heat flow of the heat-preservation-free battery module and the temperature difference of the environment temperature specifically comprises the following steps: extracting a corresponding function relation between the heat flow and the time of the non-heat-preservation battery module, and deducing a linear change relation between the total heat flow of the non-heat-preservation battery module and the temperature difference of the environment temperature according to the heat dissipation capacity of the battery module under the time history;
the linear variation relation of the total heat flow of the battery module after the heat preservation layer is added and the temperature difference of the environment temperature is determined, and the method specifically comprises the following steps: and determining the linear change relation between the total heat flow of the battery module added with the heat-insulating layer and the temperature difference of the environment temperature according to the deduced linear change relation between the total heat flow of the battery module without heat insulation and the temperature difference of the environment temperature and by combining the proposed heat-insulating index of the battery module and the actual structure size of the battery module.
3. The method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced design of the thermal resistance as claimed in claim 2, wherein the three-dimensional simulation result extracts the corresponding function relationship of the total heat flow and the time of the battery module without thermal insulation as
And the temperature difference-time relation y = T (T), and deducing the linear change relation between the total heat flow of the battery module and the temperature difference of the environment temperature ^ the change of the temperature of the battery module>
In the formula: />
t is time and R is the total equivalent thermal resistance in the direction of heat flow.
4. The method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced design of the thermal resistance as claimed in claim 3, wherein the heat-conducting theory is combined with the corresponding function relationship of the total heat flow and the time according to the corresponding function relationship of the total heat flow and the temperature difference, and the corresponding function relationship of the total heat flow and the time after the thermal insulation layer is added is preliminarily and qualitatively determined
Preliminarily and qualitatively determining that the corresponding function relation between the total heat flow and the temperature difference after the heat preservation layer is added meets->
Wherein R' is the total equivalent thermal resistance after adding an insulating layer, and R is the equivalent thermal resistance after adding an insulating layer>
5. The method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced design of thermal resistance as claimed in claim 2, wherein the thermal insulation index is an average temperature drop/rise rate, and the determination at t is made according to the thermal insulation index and the actual structural size of the battery module 0 The battery module reaches the temperature T at any moment m The specific heat capacity c of the module, the mass m of the module and the temperature T of the module m Initial temperature T of the module n Substituting into the formula Q = cm (T) n -T m ) In (1), find t 0 The total heat dissipation capacity Q of the heat dissipation process in time.
6. The method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced design of the thermal resistance as claimed in claim 5, wherein the process of obtaining the total heat dissipation capacity Q is suitable for the heat dissipation processes without thermal insulation and with thermal insulation, and the difference of the heat dissipation capacities within the same time of the heat dissipation is Δ Q = Q 1 -Q 2 Wherein Q is 1 Is t 0 Total amount of heat dissipation, Q, without thermal insulation at all times 2 Is t 0 Calculating the heat dissipation difference value delta Q by adopting the corresponding function relation of the total heat flow and the time under the condition of heat preservation at any time:
7. the method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced design of thermal resistance as claimed in claim 6, wherein the relationship of the total heat flow with or without thermal insulation-temperature difference corresponding function is as follows:
wherein: k'<k, k' is unknown, k is known; the heat dissipation capacity difference value delta Q is obtained by utilizing the function relation of total heat flow and temperature difference:
when heat preservation is determinedThe linear relation coefficient k' of the total heat flow and the temperature difference is represented in the formula>
8. The method for optimizing the thermal insulation performance of the battery module based on equivalent and balanced thermal resistance design of claim 7, wherein the linear coefficient of relationship between the total heat flow and the temperature difference is the sum of the linear coefficient of relationship between the heat flow and the temperature difference of each heat dissipation path.
9. The method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced design of the thermal resistance as claimed in claim 2, wherein a physical model of thermal resistance and heat transfer of the battery module in the three-dimensional direction is constructed, and the heat dissipation paths of the battery module after the thermal insulation layer is added are determined, and the coefficient of linear relationship between the heat flow and the temperature difference of each heat dissipation path is related to the equivalent thermal resistance on each heat dissipation path.
10. The method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced design of thermal resistance according to claim 1, wherein the method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced design of thermal resistance is characterized in that the linear variation relationship between the heat flow on different heat dissipation paths for realizing the balanced thermal resistance and the temperature difference of the environment temperature is analyzed, and a thermal resistance matching scheme for adding a thermal insulation layer under each heat dissipation path is determined, and specifically comprises the following steps:
the method comprises the steps of constructing a thermal resistance heat transfer network physical model of the battery module in the three-dimensional direction, simultaneously determining heat dissipation paths of the battery module after adding the thermal insulation layer, analyzing the linear change relationship between the heat flow on different paths for realizing thermal resistance balance and the environment temperature difference according to the linear change relationship between the total heat flow of the battery module after adding the thermal insulation layer and the environment temperature difference after determining the equivalent thermal resistance on each heat dissipation path through the heat transfer model, and determining a specific thermal insulation design scheme.
11. The method for optimizing the thermal insulation performance of the battery module based on equivalent and balanced thermal resistance design of claim 10, wherein in a series heat transfer process, the total thermal resistance of each series link is equal to the sum of the thermal resistances of each series link, wherein the unit thermal resistance is as follows:
in the formula: r is the thermal resistance of a unit structure, K/W;
a is the heat flow area of the unit structure, m 2 ；
L is the thickness of the unit structure in the heat flow direction, m;
lambda is the thermal conductivity coefficient of the unit structure material, W/(m.K);
ΣR＝R 1 +R 2 +······+R n ；
in the formula: r 1 ，R 2 ……R n The thermal resistance of each layer of the objects connected in series, K/W;
the sigma R is equivalent thermal resistance on a heat dissipation path, K/W;
the heat flow in the built thermal resistance heat transfer model is satisfied
Equivalent thermal resistance R 'on each heat transfer path' x R 'is satisfied' x And =Σr, implementing a thermal resistance equalization design, namely:
Σk′ x ＝k′
R′ 1 ＝R′ ！ ＝…R′ x wherein: x =1,2,3 \ 8230 \8230
Wherein, k' x 、R′ x Respectively representing the linear relation coefficients and the equivalent thermal resistance values of different heat dissipation paths.
12. The utility model provides a battery module heat preservation heat-proof quality optimizing system based on thermal resistance equivalence and balanced design which characterized in that specifically includes:
the three-dimensional solid heat flow simulation model building module is used for building a three-dimensional solid heat flow simulation model of the vehicle power battery module under the condition of no heat preservation;
the heat-insulation-free battery module heat flow change relation module is used for deducing a linear change relation between the total heat flow of the heat-insulation-free battery module and the temperature difference of the environment temperature;
the thermal insulation battery module heat flow change relation module is used for determining the linear change relation between the total heat flow of the battery module after the thermal insulation layer is added and the temperature difference of the environment temperature;
the thermal flow and environment temperature difference change relation analysis module is used for analyzing the linear change relation between the thermal flow and the environment temperature difference on different heat dissipation paths for realizing thermal resistance balance and determining a thermal resistance matching scheme for adding a thermal insulation layer under each heat dissipation path;
and the internal thermal resistance heat transfer network physical model building module is used for building a battery module internal thermal resistance heat transfer network physical model according to the anisotropy of the heat conduction of the battery core and determining module temperature difference design indexes.
13. A battery module, its characterized in that specifically includes:
an electric core;
the module outer frame is used for wrapping the battery cell;
the method for optimizing the thermal insulation performance of the battery module based on the equivalent and balanced thermal resistance design as claimed in any one of claims 1 to 11 is adopted for optimizing the thermal insulation performance of the battery module.
14. A battery pack, characterized in that the battery pack specifically comprises the battery module according to claim 13.
15. An electronic device, comprising: the system comprises a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory complete mutual communication through the communication bus; the memory has stored therein a computer program which, when executed by the processor, causes the processor to carry out the steps of the method of any one of claims 1 to 11.
16. A computer-readable storage medium, characterized in that it stores a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of the method of any one of claims 1 to 11.
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| CN116956378A (en) * | 2023-09-20 | 2023-10-27 | 宁波健信超导科技股份有限公司 | Superconducting magnet heat transfer analysis method, device, equipment and storage medium |
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| CN116956378A (en) * | 2023-09-20 | 2023-10-27 | 宁波健信超导科技股份有限公司 | Superconducting magnet heat transfer analysis method, device, equipment and storage medium |
| CN116956378B (en) * | 2023-09-20 | 2024-01-02 | 宁波健信超导科技股份有限公司 | Superconducting magnet heat transfer analysis method, device, equipment and storage medium |
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