Water-cooled plates and methods for improving battery thermal safety performance using elastic refrigeration materials

Abstract

This invention relates to the field of battery technology, specifically to a water-cooled plate and a method for improving battery thermal safety performance using elastic cooling materials. A battery water-cooled plate includes a water-cooled substrate, a water inlet, and a water outlet. The water-cooled substrate is made of an elastic cooling material. The water inlet and outlet are located at opposite ends of the water-cooled substrate along its length. Coolant channels are provided inside the water-cooled substrate, extending from one end to the other. There are one or more coolant channels, and they are evenly distributed. The water-cooled plate has a wave-like configuration. The water-cooled plate prepared using the elastic cooling material of this invention achieves better cooling performance, which can help improve the lifespan and safety of lithium-ion batteries.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a water-cooled plate and a method for improving the thermal safety performance of a battery by using elastic cooling materials. Background Technology

[0002] With the rapid popularization of electric vehicles, consumers and automakers are paying increasing attention to battery safety. Power batteries are not only the main power source and core component of electric vehicles, but also a major technological barrier to their rapid development. Lithium-ion batteries, with their advantages of high energy density, long cycle life, and environmental friendliness, are widely used in mobile phones, electric vehicles, power banks, and many other fields.

[0003] Elastic refrigeration is a novel refrigeration technology with enormous application potential, capable of solving most of the problems existing in traditional refrigerant refrigeration and vapor compression refrigeration technologies. It is considered one of the most promising refrigeration technologies. It boasts advantages such as environmental friendliness, high efficiency, and energy saving, offering considerable advantages in terms of cost, cooling capacity, efficiency, and feasibility. However, the elastomeric devices used in elastic refrigeration occupy a large space during deformation and have a short material lifespan, requiring continuous improvement in practical applications. Therefore, achieving a more efficient and environmentally friendly solid-state refrigeration technology remains a significant challenge.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One object of the present invention is to provide a water-cooled plate for batteries, which is beneficial to ensuring the thermal safety performance of batteries.

[0006] Another object of the present invention is to provide a method for improving the thermal safety performance of a battery by using an elastic cooling material, which can improve the safety performance of the battery.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0008] A battery water-cooled plate includes a water-cooled substrate, a water inlet, and a water outlet. The water-cooled substrate is made of an elastic cooling material. The water inlet and the water outlet are located at opposite ends of the water-cooled substrate along its length. Coolant channels are provided inside the water-cooled substrate, extending from one end to the other. There are one or more coolant channels, and the multiple coolant channels are evenly distributed. The water-cooled plate has a wave-like configuration.

[0009] In some embodiments, the elastic cooling material includes at least one of copper-zinc-aluminum composite material, nickel-titanium composite material, nickel-titanium-copper composite material, iron-palladium composite material, iron-indium-palladium composite material, iron-rhodium composite material, and nickel-manganese-indium-cobalt composite material.

[0010] In some embodiments, the material of the water-cooled substrate includes Cu. 68.13 Zn 15.74 Al1 6.13 Cu 68 Zn 16 Al1 16 Ni 50 Ti 50 Ni 32.5 Ti 50.4 Cu 12.6 Fe 68.8 Pd 31.2 Fe 49 Rh 51 Ni 45 Mn3 6.4 In 13.6 One or more of Co5.

[0011] In some embodiments, a water circulation device is also included, wherein the outlet end of the water circulation device is connected to the inlet of the water-cooled substrate, and the inlet end of the water circulation device is connected to the outlet of the water-cooled substrate, and the circulating liquid is cooled in the water circulation device to provide coolant.

[0012] In some embodiments, the water-cooled substrate includes an intermediate layer, a first end layer, and a second end layer, with the first end layer and the second end layer located on opposite sides of the intermediate layer.

[0013] In some embodiments, the intermediate layer is Cu. 68.13 Zn 15.74 Al1 6.13 and / or Cu 68 Zn 16 Al1 16 The first end layer and the second end layer are each independently Ni 50 Ti 50 Ni 32.5 Ti 50.4 Cu 12.6 Fe 68.8 Pd 31.2 Fe 49 Rh 51 and Ni 45 Mn3 6.4 In 13.6 Any of the following Co5 compounds.

[0014] A method for improving battery thermal safety performance using elastic cooling materials includes the following steps:

[0015] (a) By establishing a model and conducting theoretical analysis, the relationship between the temperature change of the elastic refrigeration material under stress was determined (1);

[0016] Relation (1): Where h is the thermal coefficient, Λ is the surface area, Text is the ambient temperature, T is the temperature of the elastic refrigeration material, l is the length of the elastic refrigeration material, and γ is the elasto-thermal constant established according to equation (1);

[0017] Obtain relation (2): T0 is the initial temperature of the elastic refrigeration material, and l0 is the initial length of the elastic refrigeration material. f T is the tensile length of the elastic refrigeration material. f is the temperature generated when the elastic refrigeration material deforms; c is the heat capacity of the elastic refrigeration material obtained from equation (2);

[0018] Obtain relation (3): R c γ is the cooling capacity of the elastic refrigeration material, T is the temperature of the elastic refrigeration material, c is the thermal melting point of the elastic refrigeration material, and Δl is the deformation of the elastic refrigeration material.

[0019] Obtain the relation (4): ΔT adi For adiabatic temperature change, ΔS is isothermal entropy change, T is ambient temperature, and C is the specific heat capacity of the elastic refrigeration material under constant stress.

[0020] Obtain relation (8): C COP，mat Q represents the solid-state elastic refrigeration performance of the elastic refrigeration material, where Q is the refrigeration capacity during the cycle and W is the input work during the cycle.

[0021] (b) Test the effect of elastic refrigeration material samples of different materials on refrigeration performance and obtain multiple performance parameters; make samples of elastic refrigeration materials of different materials and test them to verify the accuracy of the model in step (a); the relationship in step (a) can be verified and corrected through step (b);

[0022] (c) The corrected formula for the elastic cooling material is applied to the battery and verified through actual testing; the elastic cooling material is made into a water-cooled plate and used in the battery for cooling.

[0023] In some implementations, ΔS in relation (4) is obtained through relation (5):

[0024] Relation (5): T0 is obtained from relation (6);

[0025] Relation (6):

[0026] Where Q is the latent heat of the phase transformation process of the elastic refrigeration material, Ms is the temperature at which the martensitic phase transformation begins, and Af is the temperature at which the austenitic phase transformation ends.

[0027] When the elastothermal effect exhibited by the phase transition is of the first order type, ΔS is obtained through relation (7);

[0028] Relation (7): Δε represents deformation; σ represents uniaxial stress; T is the experimental temperature.

[0029] In some embodiments, the water-cooled plate includes a water-cooled substrate, a water inlet, and a water outlet. The water-cooled substrate is made of an elastic cooling material. The water inlet and the water outlet are located at opposite ends of the water-cooled substrate along its length. Coolant channels are provided inside the water-cooled substrate, extending from one end to the other. There are one or more coolant channels, and the multiple coolant channels are evenly distributed. The water-cooled plate has a wave-like configuration.

[0030] In some embodiments, the elastic cooling material includes at least one of copper-zinc-aluminum composite material, nickel-titanium composite material, nickel-titanium-copper composite material, iron-palladium composite material, iron-indium-palladium composite material, iron-rhodium composite material, and nickel-manganese-indium-cobalt composite material.

[0031] In some embodiments, the water-cooled plate further includes a water circulation device, the outlet of which is connected to the inlet of the water-cooled substrate, and the inlet of which is connected to the outlet of the water-cooled substrate. The circulating liquid is cooled in the water circulation device to provide coolant.

[0032] In some embodiments, the copper-zinc-aluminum composite material includes Cu 68.13 Zn 15.74 Al1 6.13 and Cu 68 Zn 16 Al1 16 The nickel-titanium composite material includes Ni 50 Ti 50 The nickel-titanium-copper composite material includes Ni 32.5 Ti 50.4 Cu 12.6 The iron-palladium composite material includes Fe. 68.8 Pd 31.2 The iron-rhodium composite material includes Fe. 49 Rh 51 The nickel-manganese-indium-cobalt composite material includes Ni 45 Mn3 6.4 In 13.6 Co5.

[0033] In some embodiments, the water-cooled substrate includes an intermediate layer, a first end layer, and a second end layer, with the first end layer and the second end layer located on opposite sides of the intermediate layer; the intermediate layer is Cu. 68.13 Zn 15.74 Al1 6.13 and / or Cu 68 Zn 16 Al1 16 The first end layer and the second end layer are each independently Ni 50 Ti 50 Ni 32.5 Ti 50.4 Cu 12.6 Fe 68.8 Pd 31.2 Fe 49 Rh 51 and Ni 45 Mn3 6.4 In 13.6 Any of the following Co5 compounds.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] (1) The battery of the present invention uses a water-cooled plate, which is beneficial to better cooling, can ensure the safety performance of the battery, and extend its service life.

[0036] (2) Based on the actual structure of the power battery, this invention considers the principles and types of elastothermal materials and designs related devices. Specifically, it involves summarizing and characterizing the materials based on the basic principles of the elastothermal effect, and conducting tests and characterization through relevant detection methods. Nickel-titanium based, copper-based, iron-based, ferromagnetic shape memory alloys, and elastic polymers are used as elastothermal materials to achieve the research objective of solid-state cooling, thereby solving the thermal safety issues related to power batteries. This can fundamentally guide the improvement of lithium-ion batteries.

[0037] (3) Components made with elastic cooling materials can achieve better cooling effects, which can directly guide the improvement of lithium-ion batteries from a mechanistic perspective, help improve the lifespan and safety of lithium-ion batteries, and further promote their commercial application. Using elastic cooling components will not increase the weight and size of the equipment, and can extend its service life, thereby forming an empirical analysis model that can be applied to the design and optimization of electric vehicles and power batteries. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of a water-cooled plate according to the present invention;

[0040] Figure 2 This is another schematic diagram of the water-cooled plate of the present invention;

[0041] Figure 3 This is a schematic diagram illustrating the temperature change principle of the elastic refrigeration material of the present invention.

[0042] Figure 4 The temperature changes of Cu alloy during loading and unloading processes;

[0043] Figure 5 The temperature changes of NiTi alloy wire during loading and unloading processes;

[0044] Figure 6 This shows the changes in load stress and temperature over time for FePd alloys.

[0045] Figure label:

[0046] 1-Water-cooled substrate, 2-Water inlet, 3-Water outlet, 4-Water circulation device. Detailed Implementation

[0047] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0048] According to one aspect of the present invention, the present invention relates to a battery water-cooled plate, comprising a water-cooled substrate, a water inlet and a water outlet, wherein the water-cooled substrate is made of an elastic cooling material, the water inlet and the water outlet are located at opposite ends of the water-cooled substrate along its length, a coolant channel is provided inside the water-cooled substrate, the coolant channel extends from one end of the water-cooled substrate to the other end, there are one or more coolant channels, and the plurality of coolant channels are uniformly distributed; the water-cooled plate has a wave-like configuration.

[0049] The water-cooled plate of this invention can effectively cool the battery and ensure its thermal safety performance.

[0050] In some embodiments, the elastic cooling material includes at least one of copper-zinc-aluminum composite materials, nickel-titanium composite materials, nickel-titanium-copper composite materials, iron-palladium composite materials, iron-indium-palladium composite materials, iron-rhodium composite materials, and nickel-manganese-indium-cobalt composite materials. In some embodiments, copper-based shape memory alloys are the earliest and most diverse type of shape memory alloys, and have been extensively studied due to their excellent shape memory properties and low cost. Binary nickel-titanium alloys, with their excellent superelasticity, corrosion resistance, biocompatibility, and shape memory effect, immediately attracted widespread attention and have rich applications in the aerospace, medical, and construction industries. Compared to applications in other fields, the significant elastothermic effect present in NiTi alloys is a significant advantage.

[0051] In some embodiments, the material of the water-cooled substrate includes Cu. 68.13 Zn 15.74 Al1 6.13 Cu 68 Zn 16 Al1 16 Ni 50 Ti 50 Ni 32.5 Ti 50.4 Cu 12.6 Fe 68.8 Pd 31.2 Fe 49 Rh 51 Ni 45 Mn3 6.4 In 13.6 One or more of Co5.

[0052] In some embodiments, a water circulation device is also included, wherein the outlet of the water circulation device is connected to the inlet of the water-cooled substrate, and the inlet of the water circulation device is connected to the outlet of the water-cooled substrate. The circulating fluid is cooled in the water circulation device to provide coolant. The water circulation device is connected to the water-cooled substrate via pipelines.

[0053] In some embodiments, parameters such as the pore size of the coolant channels and the thickness of the water-cooling plate are designed specifically according to the specific battery structure. In some embodiments, the pore size of the water-cooling plate is uniformly distributed.

[0054] In some embodiments, the water-cooled substrate includes an intermediate layer, a first end layer, and a second end layer, with the first end layer and the second end layer located on opposite sides of the intermediate layer. In some embodiments, the intermediate layer is Cu. 68.13 Zn 15.74 Al1 6.13 and / or Cu 68 Zn 16 Al116 The first end layer and the second end layer are each independently Ni 50 Ti 50 Ni 32.5 Ti 50.4 Cu 12.6 Fe 68.8 Pd 31.2 Fe 49 Rh 51 and Ni 45 Mn3 6.4 In 13.6 Any one of Co5. The present invention uses the above-mentioned elastic refrigeration material to prepare a water-cooled plate with a specific structure, which is more conducive to ensuring the cooling effect and ensuring the safety performance of the battery.

[0055] The water-cooled plate of the present invention has a good cooling effect. Actual verification shows that it can keep the outlet water temperature below 32°C during thermal runaway, such as 22°C, 25°C, 28°C, 30°C, etc.

[0056] According to another aspect of the present invention, the present invention also relates to a method for improving the thermal safety performance of a battery by applying an elastic cooling material, comprising the following steps:

[0057] (a) By establishing a model and conducting theoretical analysis, the relationship between the temperature change of the elastic refrigeration material under stress was determined (1);

[0058] Relation (1): Where h is the thermal coefficient, Λ is the surface area, Text is the ambient temperature, T is the temperature of the elastic refrigeration material, l is the length of the elastic refrigeration material, and γ is the elasto-thermal constant established according to equation (1);

[0059] Obtain relation (2): T0 is the initial temperature of the elastic refrigeration material, and l0 is the initial length of the elastic refrigeration material. f T is the tensile length of the elastic refrigeration material. f is the temperature generated when the elastic refrigeration material deforms; c is the heat capacity of the elastic refrigeration material obtained from equation (2);

[0060] Obtain relation (3): R c γ is the cooling capacity of the elastic refrigeration material, T is the temperature of the elastic refrigeration material, c is the thermal melting point of the elastic refrigeration material, and Δl is the deformation of the elastic refrigeration material.

[0061] Obtain the relation (4): ΔT adiFor adiabatic temperature change, ΔS is isothermal entropy change, T is ambient temperature, and C is the specific heat capacity of the elastic refrigeration material under constant stress.

[0062] Obtain relation (8): C COP，mat Q represents the solid-state elastic refrigeration performance of the elastic refrigeration material, where Q is the refrigeration capacity during the cycle and W is the input work during the cycle.

[0063] (b) Test the effect of elastic refrigeration material samples of different materials on refrigeration performance and obtain multiple performance parameters; make samples of elastic refrigeration materials of different materials and test them to verify the accuracy of the model in step (a); the relationship in step (a) can be verified and corrected through step (b);

[0064] (c) The corrected formula for the elastic cooling material is applied to the battery and verified through actual testing; the elastic cooling material is made into a water-cooled plate and used in the battery for cooling.

[0065] Based on the fundamental principle of the elasto-thermal effect, this invention summarizes and characterizes materials through relevant tests to achieve the research objective of solid-state cooling, thereby solving thermal safety issues related to power batteries and providing fundamental guidance for the improvement of lithium-ion batteries.

[0066] In some implementations, step (1) involves determining the impact of different elastic cooling materials on cooling efficiency. This is achieved by establishing an equivalent temperature change equation and a set of n equations concerning the electromotive force. Analysis is then used to determine the relative performance of different elastic cooling materials. Step (2) involves experimental testing to determine the impact of different elastic cooling material samples on cooling efficiency. Physical parameters, such as applied stress and entropy change, are obtained through testing. Various samples are then prepared and tested to verify the accuracy of the model. Step (3) involves applying the corrected model to the electric vehicle power battery device and then verifying the model's accuracy through actual testing. If problems arise, step (1) is repeated.

[0067] In some implementations, establishing such Figure 1 Based on the principle model, the differential equation for the temperature change of the elastic refrigeration material under stress, i.e., relation (1), is determined through model establishment and theoretical analysis. Under the assumption that heat exchange between the material and the environment is accomplished by convection and radiation, relation (1) is obtained.

[0068] In some implementations, ΔS in relation (4) is obtained through relation (5): Relation (5): T0 is obtained from relation (6); relation (6): Where Q represents the latent heat of the phase transformation process in the elastic-thermal material. The martensitic phase transformation is a first-order phase transformation, and the latent heat Q can be measured using a quasi-direct method via differential scanning calorimetry (DSC). Ms is the temperature at which the martensitic phase transformation begins; Af is the temperature at which the austenitic phase transformation ends. Substituting the calculated ΔS into the Clapeyron-Clausius equation yields the adiabatic temperature change of the elastic-thermal material. Indirect measurement method: First, measure the stress-strain curve or strain-temperature curve under a certain load on the sample, then calculate using the Clapeyron-Clausius equation.

[0069] Equation (4) shows that isothermal entropy decrease leads to temperature increase, and conversely, isothermal entropy increase leads to temperature decrease, which is consistent with the temperature change of materials during stress loading and release. When the elasto-thermal effect of the phase transition is of the first order type, ΔS is obtained through equation (7); Equation (7): Δε represents deformation; σ represents uniaxial stress; T is the experimental temperature. dσ / dT is the relationship between the critical stress of martensitic transformation and the experimental temperature. Currently, the ΔS of martensitic transformation in shape memory alloys is generally measured by quasi-direct or indirect methods.

[0070] In some implementations, the performance parameter includes: phase transition temperature T t、 Applied stress Δσ, adiabatic entropy change ΔS e Entropy change ΔS i Adiabatic temperature change ΔT d The temperature change ΔT is calculated using the entropy change generated during the phase transition. t .

[0071] In some embodiments, the test results of the performance parameters of the elastic cooling material include: Cu 68.13 Zn 15.74 Al1 6.13 Phase transition temperature T t The K value is 230 K, the applied stress Δσ is 120 MPa, and the entropy change ΔS i 21 J·kg -1 ·K -1 adiabatic entropy change ΔS e 11 J·kg -1 ·K -1 Adiabatic temperature change ΔT d The temperature change is ΔT = 6K. t 11K. Cu 68 Zn 16 Al1 16 Phase transition temperature T t The pressure is 200K, the applied stress Δσ is 250MPa, and the entropy change ΔS i 18 J·kg -1 ·K-1 adiabatic entropy change ΔS e 13 J·kg -1 ·K -1 Adiabatic temperature change ΔT d The temperature change is ΔT = 6K. t 12K; Ni 50 Ti 50 Phase transition temperature T t The temperature is 260 K, the applied stress Δσ is 230 MPa, and the adiabatic entropy change ΔS e 26 J·kg -1 ·K -1 Adiabatic temperature change ΔT d It is 26K. Ni 32.5 Ti 50.4 Cu 12.6 Phase transition temperature T t The temperature is 320 K, the applied stress Δσ is 300 MPa, and the adiabatic entropy change ΔS e 21 J·kg -1 ·K -1 Adiabatic temperature change ΔT d 6K. Fe 68.8 Pd 31.2 Phase transition temperature T t The pressure is 250K, the applied stress Δσ is 200MPa, and the entropy change ΔS i 5J·kg -1 ·K -1 Adiabatic temperature change ΔT d 3K. Fe 49 Rh 51 Phase transition temperature T t The temperature is 315 K, the applied stress Δσ is 530 MPa, and the adiabatic entropy change ΔS e 7 J·kg -1 ·K -1 Adiabatic temperature change ΔT d 5K. Ni 45 Mn3 6.4 In 13.6 Co5: Phase transition temperature T t The temperature is 250K, the applied stress Δσ is 150MPa, and the adiabatic entropy change ΔS e 5J·kg -1 ·K -1 Adiabatic temperature change ΔT d It is 4K.

[0072] For relation (8), C COP，mat The larger the value, the better the refrigeration performance of the material. Further considering factors such as heat transfer medium and circulation frequency, the refrigeration performance coefficient of the entire device is calculated.

[0073] In some embodiments, the water-cooled plate includes a water-cooled substrate, a water inlet, and a water outlet. The water-cooled substrate is made of an elastic cooling material. The water inlet and the water outlet are located at opposite ends of the water-cooled substrate along its length. Coolant channels are provided inside the water-cooled substrate, extending from one end to the other. There are one or more coolant channels, and they are evenly distributed. The water-cooled plate has a wave-like configuration. This water-cooled plate structure can better cool the battery, thereby improving the battery's thermal safety performance.

[0074] In some embodiments, the water-cooled plate further includes a water circulation device, the outlet of which is connected to the inlet of the water-cooled substrate, and the inlet of which is connected to the outlet of the water-cooled substrate. The circulating liquid is cooled in the water circulation device to provide coolant.

[0075] In some embodiments, the elastic cooling material includes one or more of copper-zinc-aluminum composite materials, nickel-titanium composite materials, nickel-titanium-copper composite materials, iron-palladium composite materials, iron-indium-palladium composite materials, iron-rhodium composite materials, and nickel-manganese-indium-cobalt composite materials. In some embodiments, the copper-zinc-aluminum composite material includes Cu 68.13 Zn 15.74 Al1 6.13 and Cu 68 Zn 16 Al1 16 The nickel-titanium composite material includes Ni 50 Ti 50 The nickel-titanium-copper composite material includes Ni 32.5 Ti 50.4 Cu 12.6 The iron-palladium composite material includes Fe. 68.8 Pd 31.2 The iron-rhodium composite material includes Fe. 49 Rh 51 The nickel-manganese-indium-cobalt composite material includes Ni 45 Mn3 6.4 In 13.6 Co5.

[0076] In some embodiments, the water-cooled substrate includes an intermediate layer, a first end layer, and a second end layer, with the first end layer and the second end layer located on opposite sides of the intermediate layer; the intermediate layer is Cu. 68.13 Zn 15.74 Al1 6.13 and / or Cu 68 Zn 16 Al1 16 The first end layer and the second end layer are each independently Ni 50 Ti 50Ni 32.5 Ti 50.4 Cu 12.6 Fe 68.8 Pd 31.2 Fe 49 Rh 51 and Ni 45 Mn3 6.4 In 13.6 Any of Co5. The water-cooled plate with a specific structure prepared by the above-mentioned elastic refrigeration material is beneficial to ensuring the cooling effect and better ensuring the safety performance of the battery. Practical verification has shown that it can keep the outlet pipe temperature below 32°C during thermal runaway, for example, 22°C, 25°C, 28°C, 30°C, etc.

[0077] The following explanation, in conjunction with specific embodiments, further clarifies the situation.

[0078] Example 1

[0079] (a) Determine the impact of different elastic refrigeration materials on refrigeration efficiency. By establishing an equivalent temperature change equation, a system of n equations concerning the electromotive force is established. Through analysis, the advantages and disadvantages of elastic refrigeration performance of different materials are derived. (The system is then established as follows...) Figure 3 Based on the principle model, the differential equation for the temperature change of the elastic refrigeration material under stress, i.e., the relation (1), is determined through model establishment and theoretical analysis. This is under the assumption that heat exchange between the material and the environment is accomplished by convection and radiation.

[0080] Relation (1): Where h is the thermal coefficient, Λ is the surface area, Text is the ambient temperature, T is the temperature of the elastic refrigeration material, l is the length of the elastic refrigeration material, and γ is the elasto-thermal constant established according to equation (1).

[0081] Obtain relation (2): T0 is the initial temperature of the elastic refrigeration material, and l0 is the initial length of the elastic refrigeration material. f T is the tensile length of the elastic refrigeration material. f is the temperature generated when the elastic refrigeration material deforms; c is the heat capacity of the elastic refrigeration material obtained from equation (2).

[0082] Obtain relation (3): R c γ is the cooling capacity of the elastic refrigeration material, T is the temperature of the elastic refrigeration material, c is the thermal melting point of the elastic refrigeration material, and Δl is the deformation of the elastic refrigeration material.

[0083] Obtain the relation (4): ΔT adiFor adiabatic temperature change, ΔS is the isothermal entropy change, T is the ambient temperature, and C is the specific heat capacity of the elastic refrigeration material under constant stress.

[0084] ΔS is obtained through relation (5): Relation (5): T0 is obtained from relation (6); relation (6): Where Q is the latent heat of the phase transformation process of the elastic refrigeration material, Ms is the temperature at which the martensitic phase transformation begins, and Af is the temperature at which the austenitic phase transformation ends. When the elasto-thermal effect exhibited by the phase transformation is of the first-order type, ΔS is obtained through the relation (7);

[0085] Relation (7): Δε represents deformation; σ represents uniaxial stress; T is the experimental temperature.

[0086] Obtain relation (8): C COP，mat Q represents the solid-state elastic refrigeration performance of the elastic refrigeration material, where Q is the refrigeration capacity during the cycle and W is the input work during the cycle.

[0087] (b) Test the effect of elastic refrigeration material samples of different materials on refrigeration performance and obtain multiple performance parameters; make samples of elastic refrigeration materials of different materials and test them to verify the accuracy of the model in step (a).

[0088] Different types of elastic refrigeration materials were selected for testing, and the specific performance parameters are shown in Table 1. Phase change temperature T t、 Applied stress Δσ, adiabatic entropy change ΔS e Entropy change ΔS i Adiabatic temperature change ΔT d The temperature change ΔT is calculated using the entropy change generated during the phase transition. t .

[0089] Table 1 Performance parameters of elastic refrigeration materials

[0090]

[0091] In Table 1, Cu 68.13 Zn 15.74 Al1 6.13 Phase transition temperature T t The K value is 230 K, the applied stress Δσ is 120 MPa, and the entropy change ΔS i 21 J·kg -1 ·K -1 adiabatic entropy change ΔS e 11 J·kg -11 ·K -1 Adiabatic temperature change ΔT d The temperature change is ΔT = 6K. t11K. Cu 68 Zn 16 Al1 16 Phase transition temperature T t The pressure is 200K, the applied stress Δσ is 250MPa, and the entropy change ΔS i 18 J·kg -1 ·K -1 adiabatic entropy change ΔS e 13 J·kg -1 ·K -1 Adiabatic temperature change ΔT d The temperature change is ΔT = 6K. t 12K; Ni 50 Ti 50 Phase transition temperature T t The temperature is 260 K, the applied stress Δσ is 230 MPa, and the adiabatic entropy change ΔS e 26 J·kg -1 ·K -1 Adiabatic temperature change ΔT d It is 26K. Ni 32.5 Ti 50.4 Cu 12.6 Phase transition temperature T t The temperature is 320 K, the applied stress Δσ is 300 MPa, and the adiabatic entropy change ΔS e 21 J·kg -1 ·K -1 Adiabatic temperature change ΔT d 6K. Fe 68.8 Pd 31.2 Phase transition temperature T t The pressure is 250K, the applied stress Δσ is 200MPa, and the entropy change ΔS i 5J·kg -1 ·K -1 Adiabatic temperature change ΔT d 3K. Fe 49 Rh 51 Phase transition temperature T t The temperature is 315 K, the applied stress Δσ is 530 MPa, and the adiabatic entropy change ΔS e 7 J·kg -1 ·K -1 Adiabatic temperature change ΔT d 5K. Ni 45 Mn3 6.4 In 13.6 Co5: Phase transition temperature T t The temperature is 250K, the applied stress Δσ is 150MPa, and the adiabatic entropy change ΔS e 5J·kg -1 ·K -1 Adiabatic temperature change ΔTd It is 4K.

[0092] (c) Step (b) can be used to verify and correct the relationship in step (a), and the corrected relationship of the elastic cooling material can be applied to the battery and verified through actual testing.

[0093] Example 2

[0094] The cooling performance of Cu-Zn-Al single-crystal alloys (with specific lattice parameters of each metal in the range of 0-1) at different temperatures was evaluated through theoretical calculations, and the corresponding theoretical ΔT was obtained. adi It can reach -15K, and the maximum martensite ΔS is approximately 20 J·kg. -1 ·K -1 And cooling can be achieved by applying very low stress, such as... Figure 4 As shown. Water-cooled plates made using this copper-based shape memory alloy, such as... Figure 1 , Figure 2 As shown in the experiment, it was found that in addition to water cooling, the phase change heat effect of Cu-based shape memory alloy resulted in a more significant cooling effect, indicating that this water cooling plate is more beneficial for cooling the power battery module.

[0095] A type of water-cooled plate, such as Figure 2 As shown, it includes a water-cooled substrate 1, a water inlet 2, and a water outlet 3. The water-cooled substrate 1 is made of Cu. 68.13 Zn 15.74 Al1 6.13 The inlet 2 and outlet 3 are located at opposite ends of the water-cooled substrate 1 along its length. The water-cooled substrate 1 has multiple coolant channels extending from one end to the other, evenly distributed. The water-cooled plate has a wave-like configuration. A water circulation device 4 is also included. The outlet of the water circulation device 4 is connected to the inlet 2 of the water-cooled substrate 1, and the inlet of the water circulation device 4 is connected to the outlet 3 of the water-cooled substrate 1. The circulating fluid is cooled within the water circulation device 4 to provide coolant.

[0096] Example 3

[0097] The NiTi alloy (with specific lattice parameters for each of the aforementioned metals within the range of 0-1) exhibits a significant elasto-thermal effect, resulting in an adiabatic temperature change of -14K. COP，matThe value is 12.6. Tensile treatment of sheet-like NiTi alloys revealed that the alloy sheets could achieve a maximum cooling effect of approximately -16K under 500MPa of tensile stress. NiTi alloy wires could achieve an adiabatic cooling of -17K under 600MPa of tensile stress. Tensile / release operations on NiTi alloy wires at different temperatures showed a maximum cooling change of -21K, such as... Figure 5 As shown, NiTi alloy was fabricated into a strip structure and stretched to form a cooling plate. Temperature detection using an infrared camera revealed that the NiTi alloy strip could achieve a temperature drop of approximately -15K.

[0098] A type of water-cooled plate, such as Figure 2 As shown, it includes a water-cooled substrate 1, a water inlet 2, and a water outlet 3. The water-cooled substrate 1 is made of Ni. 50 Ti 50 The inlet 2 and outlet 3 are located at opposite ends of the water-cooled substrate 1 along its length. The water-cooled substrate 1 has multiple coolant channels extending from one end to the other, evenly distributed. The water-cooled plate has a wave-like configuration. A water circulation device 4 is also included. The outlet of the water circulation device 4 is connected to the inlet 2 of the water-cooled substrate 1, and the inlet of the water circulation device 4 is connected to the outlet 3 of the water-cooled substrate 1. The circulating fluid is cooled within the water circulation device 4 to provide coolant.

[0099] Example 4

[0100] For the first time, an adiabatic cooling of -5.17 K was detected in the stress-induced ferromagnetic-antiferromagnetic transformation of Fe-Rh alloys, and the isothermal entropy change of the material reached 13 J·kg under stress of 529 MPa. -1 ·K -1 .

[0101] Fe-Pd-based shape memory alloys are also a major source of elasto-thermal effects in Fe-based alloys, such as... Figure 6 As shown, the alloy exhibits an adiabatic temperature change of -2K under a stress of 100MPa. With the addition of a certain amount of In, the Pd-In-Fe alloy exhibits an adiabatic temperature change of -5.4K and also has good superelasticity and ductility.

[0102] A water-cooled plate includes a water-cooled substrate 1, a water inlet 2, and a water outlet 3. The water-cooled substrate 1 is made of Pd-In-Fe material. The water inlet 2 and the water outlet 3 are located at opposite ends of the water-cooled substrate 1 along its length. Multiple coolant channels are provided inside the water-cooled substrate 1, extending from one end to the other, and are evenly distributed. The water-cooled plate has a wave-like configuration. It also includes a water circulation device 4. The outlet end of the water circulation device 4 is connected to the water inlet 2 of the water-cooled substrate 1, and the inlet end of the water circulation device 4 is connected to the water outlet 3 of the water-cooled substrate 1. The circulating fluid is cooled within the water circulation device 4 to provide coolant.

[0103] Example 5

[0104] A type of water-cooled plate, such as Figure 2 As shown, it includes a water-cooled substrate 1, a water inlet 2, and a water outlet 3. The water-cooled substrate 1 includes an intermediate layer, a first end layer, and a second end layer. The intermediate layer is Cu. 68.13 Zn 15.74 Al1 6.13 The first end layer and the second end layer are located on either side of the intermediate layer, and the first end layer and the second end layer are Ni, respectively. 32.5 Ti 50.4 Cu 12.6 The inlet 2 and outlet 3 are located at opposite ends of the water-cooled substrate 1 along its length. The water-cooled substrate 1 has multiple coolant channels extending from one end to the other, evenly distributed. The water-cooled plate has a wave-like configuration. A water circulation device 4 is also included. The outlet of the water circulation device 4 is connected to the inlet 2 of the water-cooled substrate 1, and the inlet of the water circulation device 4 is connected to the outlet 3 of the water-cooled substrate 1. The circulating fluid is cooled within the water circulation device 4 to provide coolant.

[0105] Example 6

[0106] A type of water-cooled plate, such as Figure 2 As shown, it includes a water-cooled substrate 1, a water inlet 2, and a water outlet 3. The water-cooled substrate 1 includes an intermediate layer, a first end layer, and a second end layer. The intermediate layer is Cu. 68.13 Zn 15.74 Al1 6.13 The first end layer and the second end layer are located on either side of the intermediate layer, and the first end layer and the second end layer are Ni, respectively. 45 Mn3 6.4 In 13.6 Co 5。The inlet 2 and the outlet 3 are located at opposite ends of the water-cooled substrate 1 along its length. The water-cooled substrate 1 has multiple coolant channels extending from one end to the other, evenly distributed. The water-cooled plate has a wave-like configuration. A water circulation device 4 is also included. The outlet of the water circulation device 4 is connected to the inlet 2 of the water-cooled substrate 1, and the inlet of the water circulation device 4 is connected to the outlet 3 of the water-cooled substrate 1. The circulating fluid is cooled within the water circulation device 4 to provide coolant.

[0107] Example 7

[0108] A type of water-cooled plate, such as Figure 2 As shown, it includes a water-cooled substrate 1, a water inlet 2, and a water outlet 3. The water-cooled substrate 1 includes an intermediate layer, a first end layer, and a second end layer. The intermediate layer is Cu. 68 Zn 16 Al1 16 The first end layer and the second end layer are located on either side of the intermediate layer, and the first end layer and the second end layer are Ni, respectively. 45 Mn3 6.4 In 13.6 Co 5。 The inlet 2 and the outlet 3 are located at opposite ends of the water-cooled substrate 1 along its length. The water-cooled substrate 1 has multiple coolant channels extending from one end to the other, evenly distributed. The water-cooled plate has a wave-like configuration. A water circulation device 4 is also included. The outlet of the water circulation device 4 is connected to the inlet 2 of the water-cooled substrate 1, and the inlet of the water circulation device 4 is connected to the outlet 3 of the water-cooled substrate 1. The circulating fluid is cooled within the water circulation device 4 to provide coolant.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the thermal safety performance of a battery using an elastocaloric material, characterized in that, The method comprises the following steps: (a) determining the relationship formula (1) of the temperature change of the elastic refrigeration material under stress by establishing a model and theoretically analyzing; Relationship (1): where h is the thermal coefficient, Λ is the surface area, Text is the ambient temperature, T is the temperature of the elastocaloric material, l is the length of the elastocaloric material, and γ is the elastocaloric constant established according to relationship (1); The relationship (2) is obtained: T0 is the temperature of the initial state of the elastic refrigeration material, l0 is the length of the initial state of the elastic refrigeration material, l f is the stretched length of the elastic refrigeration material; T f is the temperature generated when the elastic refrigeration material deforms; and c is the heat capacity of the elastic refrigeration material obtained according to the relationship (2). The relationship (3) is obtained: , R c is the refrigeration capacity of the elastic refrigeration material, γ is the pyroelectric constant, T is the temperature of the elastic refrigeration material, c is the heat capacity of the elastic refrigeration material, and Δl is the deformation of the elastic refrigeration material. The relationship (4) is obtained: , ΔT adi is the adiabatic temperature change, ΔS is the isothermal entropy change, T is the ambient temperature, and C is the specific heat capacity of the elastic refrigeration material under a constant stress. The relationship (8) is obtained: , C COP，mat is the solid-state elastic refrigeration performance of the elastic refrigeration material, Q is the refrigeration capacity in the cycle process, and W is the input work in the cycle process. (b) testing the influence of the elastic refrigeration material samples of different materials on the refrigeration efficiency, obtaining multiple performance parameters; the elastic refrigeration materials of different materials are made into samples and tested to verify the accuracy of the model of step (a); the relationship formula of step (a) can be verified and corrected through step (b); (c) applying the corrected relationship formula of the elastic refrigeration material to the battery and verifying it through actual testing; the elastic refrigeration material is made into a water cooling plate for cooling in the battery.

2. The method of claim 1, wherein the elastic refrigerant is applied to the battery to improve thermal safety performance of the battery. In the relationship formula (4), ΔS is obtained through the relationship formula (5): Equation (5): T0 is obtained from Equation (6); Relationship (6): ; Wherein, Q is the latent heat of the phase change process of the elastic refrigeration material, Ms is the temperature at which the martensite phase change begins; Af is the temperature at which the austenite phase change ends; When the elastic-thermal effect of the phase change is of the first order type, ΔS is obtained through the relationship formula (7); Equation (7): where Δε represents the deformation; σ represents the uniaxial stress; and T is the experimental temperature.

3. The method of claim 1, wherein the elastic refrigerant is applied to the battery to improve thermal safety performance of the battery. The water cooling plate comprises a water cooling base plate, a water inlet and a water outlet, the material of the water cooling base plate comprises an elastic refrigeration material, the water inlet and the water outlet are located at the two ends of the water cooling base plate along the length direction of the water cooling base plate, the inside of the water cooling base plate is provided with a cooling liquid channel, the cooling liquid channel extends from one end of the water cooling base plate to the other end, the cooling liquid channel has one or more, and the multiple cooling liquid channels are uniformly distributed; the water cooling plate has a wave configuration.

4. The method of claim 3, wherein the elastic refrigerant is applied to the battery to improve thermal safety performance of the battery. The elastic refrigeration material comprises at least one of copper-zinc-aluminum composite material, nickel-titanium composite material, nickel-titanium-copper composite material, iron-palladium composite material, iron-indium-palladium composite material, iron-rhodium composite material and nickel-manganese-indium-cobalt composite material; And / or, the water cooling plate further comprises a water circulating device, the water outlet end of the water circulating device is connected to the water inlet of the water cooling base plate, the water inlet end of the water circulating device is connected to the water outlet of the water cooling base plate, and the circulating liquid is cooled in the water circulating device to provide cooling liquid.

5. The method of claim 4, wherein the elastic refrigerant is applied to the battery to improve thermal safety performance of the battery. The copper-zinc-aluminum composite includes Cu 68.13 Zn 15.74 Al1 6.13 and Cu 68 Zn 16 Al1 16 ; the nickel-titanium composite includes Ni 50 Ti 50 ; the nickel-titanium-copper composite includes Ni 32.5 Ti 50.4 Cu 12.6 ; the iron-palladium composite includes Fe 68.8 Pd 31.2 ; the iron-rhodium composite includes Fe 49 Rh 51 ; the nickel-manganese-indium-cobalt composite includes Ni 45 Mn3 6.4 In 13.6 Co5.

6. The method of claim 5, wherein the elastic refrigerant is applied to the battery to improve thermal safety performance of the battery. The water cooling base plate comprises an intermediate layer, a first end layer and a second end layer, and the first end layer and the second end layer are located on the two sides of the intermediate layer; the intermediate layer is Cu 68.13 Zn 15.74 Al1 6.13 and / or Cu 68 Zn 16 Al1 16 the first end layer and the second end layer are each independently one of Ni 50 Ti 50 , Ni 32.5 Ti 50.4 Cu 12.6 , Fe 68.8 Pd 31.2 , Fe 49 Rh 51 and Ni 45 Mn3 6.4 In 13.6 Co5.

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