Base material with heat insulation function as well as preparation method and application of base material

Abstract

The invention relates to the technical field of battery surface protection, in particular to a base material with a heat insulation function and a preparation method and application of the base material with the heat insulation function. Wherein the high-entropy alloy powder is composed of the following elements in atomic percent: 25%-30% of Al, 17%-20% of Co, 17%-20% of Cr, 17%-20% of Fe and 17%-20% of Ni; spherical Al1. 5CoCrFeNi high-entropy alloy powder with uniform particle size distribution is prepared by using a step-by-step mechanical alloying method, and a base material of a high-entropy alloy functional layer with low heat conductivity and high hardness is obtained by adopting supersonic flame spraying; the base material is suitable for surface thermal protection of the battery module, effectively reduces the surface temperature of the battery and reduces heat transfer, so that stable operation of the battery in a high-temperature environment is guaranteed, and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery surface protection, in particular to a substrate with heat insulation function and a preparation method and application thereof. BACKGROUND

[0002] Renewable energy sources such as solar energy and wind energy have gradually become an important part of energy supply due to their clean and renewable characteristics. However, these renewable energy sources have intermittency and instability, which poses a serious challenge to the stable operation of the power grid. As the core component of the energy storage system, the performance of the energy storage battery directly affects the efficiency and stability of the entire system.

[0003] Thermal runaway propagation is a harmful behavior that occurs between battery modules and systems. When a battery cell is triggered by mechanical, electrical and thermal triggers, thermal runaway of a certain battery cell will occur, and the temperature of the single battery cell will rapidly rise to about 1000℃, and the heat will be rapidly transferred to the adjacent battery, causing the surrounding battery to undergo thermal runaway, and the thermal propagation behavior occurs between battery cells. Thermal propagation not only occurs between battery cells, but also spreads between battery modules. In the prior art, a battery pack design without modules is used, and thermal propagation spreads between battery cells. Compared to thermal propagation between modules, thermal propagation between battery cells is more rapid. Once thermal runaway propagation occurs in the entire battery system, the loss will be incalculable. It is of great significance to limit battery thermal runaway propagation and suppress the expansion of accidents by constructing a functional layer with heat insulation and fire resistance on the surface of battery cells, battery modules and key components of battery clusters. SUMMARY

[0004] In order to solve the technical problem of thermal runaway propagation of energy storage batteries, a substrate with heat insulation function and a preparation method and application thereof are provided. The present application constructs a heat insulation functional layer on the surface of battery cells, battery modules and key components of battery clusters, and the functional layer has good heat insulation effect, and the thermal conductivity coefficient at 1000℃ is less than 20 W / (m·K).

[0005] In order to achieve the above purpose, the present application realizes the following technical scheme:

[0006] A preparation method of a substrate with heat insulation function, comprising the following steps:

[0007] S1, after surface purification treatment of the metal substrate, roughening treatment is carried out to obtain a pretreated substrate, and the pretreated substrate is preheated for use;

[0008] S2, the high-entropy alloy powder prepared by the step-by-step mechanical alloying is sprayed onto the surface of the preheated pretreated substrate, to obtain a substrate with heat insulation function;

[0009] The high-entropy alloy powder is composed of elements with the following atomic percentages:

[0010] Al 25%-30%, Co 17%-20%, Cr 17%-20%, Fe 17%-20%, and Ni 17%-20%.

[0011] Further, the high-entropy alloy powder is composed of elements with the following atomic percentages:

[0012] Al 26%-29%, Co 17.5%-19%, Cr 17.5%-19%, Fe 17.5%-19%, and Ni 17.5%-19%.

[0013] Further, the step-by-step mechanical alloying is to first weigh and mix the elemental powders Cr, Co, Fe, and Ni according to the ratio, then add elemental powder Al for further ball milling to an average particle size of 20-40 microns.

[0014] Further, the specific method of the step-by-step mechanical alloying is:

[0015] The elemental powders Cr, Co, Fe, and Ni are weighed according to the ratio and poured into the ball milling tank, then the grinding beads are added, sealed, vacuumed, and filled with argon, and then placed in a planetary ball mill at a speed of 250-500 rpm for the first stage of ball milling for 15-25 hours. The formula amount of elemental powder Al is added to the ball milling tank, sealed again, vacuumed, and filled with argon, and then placed in a planetary ball mill at a speed of 200-250 rpm for the second stage of ball milling for 30-50 hours.

[0016] Further, the specific operation of vacuuming and filling with argon is to vacuum the inside of the ball milling tank to below 10 Pa and maintain for 10 minutes, then introduce argon with a purity of at least 4N to the tank pressure of 0.5 MPa for 10 minutes;

[0017] The running setting of the planetary ball mill is one cycle time: forward rotation for 10 minutes, stop for 2 minutes, reverse rotation for 10 minutes, and stop for 2 minutes.

[0018] Further, the grinding beads with diameters of 15 mm, 10 mm, 6 mm, and 5 mm are configured according to the mass ratio of 1:4:2:1, and the total weight of the grinding beads and the total weight of the elemental powders are mixed according to the ratio of 10-20:1.

[0019] Preferably, the high-entropy alloy powder is composed of elements Al, Cr, Co, Fe, Ni in a molar ratio of 1.5:1:1:1:1 (corresponding to atomic percentage of about Al 27.27%, Cr 18.18%, Co 18.18%, Fe 18.18%, Ni 18.19%); the first-stage ball milling time is 20h, and the second-stage ball milling time is 40-50h.

[0020] Further, in S2, the spraying adopts oxygen-kerosene supersonic flame spraying, oxygen is used as a combustion-supporting agent, kerosene is used as fuel, argon is used as powder feeding carrier gas, and air is used as cooling medium, and the spraying parameters are as follows: oxygen flow rate is 15 L / h, kerosene flow rate is 32 L / h, air flow rate is 350 L / min, spraying distance is 350 mm, spraying step distance is 3 mm, spraying speed is 800 mm / s, powder feeding voltage is 3.3 V, and powder feeding rate is 32 g / min. If the kerosene flow rate is lower than the value, the particle melting effect is poor, and the spraying effect is poor; if the kerosene flow rate is higher than the value, the substrate is easy to bend.

[0021] Further, in S1, the roughening treatment adopts brown corundum sand with a particle size of 60 mesh for sand blasting roughening, and the sand blasting pressure is 0.3-0.5 MPa, so that the surface roughness of the substrate after sand blasting reaches 2.5-3 microns.

[0022] In S1, the preheating temperature reaches 80-120 DEG C.

[0023] The metal substrate is selected from one of an aluminum alloy, a magnesium alloy and steel.

[0024] In another aspect of the present application, a substrate with a heat insulation function obtained by the above preparation method is provided, and the substrate has a heat insulation function layer on the surface of the metal substrate, and the material of the heat insulation function layer is Al 1.5 CoCrFeNi high-entropy alloy, the thickness of the functional layer is 200-300 microns, and the hardness is 700-800 HV 0.3 The thermal conductivity at a temperature of 25-1000 DEG C decreases with the increase of temperature, and the functional layer does not crack at 1000 DEG C, and the thermal conductivity at 1000 DEG C is lower than 20 W / (m·K).

[0025] In a third aspect of the present application, the substrate with a heat insulation function obtained by the above preparation method is applied to surface protection in an energy storage battery, specifically in key components of a battery monomer, a battery module and / or a battery cluster. For example, as a battery monomer shell, the surface with the functional layer is an outer surface, and the thermal conductivity at high temperature is low, so that the spread of thermal runaway can be effectively controlled.

[0026] Beneficial technical effects: the substrate with Al 1.5The melting point of the substrate of the CoCrFeNi high-entropy alloy is higher than 1200 DEG C, and the structural stability (such as BCC / FCC solid solution phase) can be maintained at high temperature, which is much better than that of the traditional metal coating; in addition, Al 1.5 The CoCrFeNi high-entropy alloy has a multi-element synergistic effect, in which the Al element forms a dense Al2O3 oxide film at high temperature to improve the oxidation resistance and heat insulation, the Cr and Fe elements can enhance the corrosion resistance to avoid chemical corrosion caused by electrolyte penetration, and the Co / Ni elements can regulate the heat conduction capacity to achieve the heat insulation property of "low thermal conductivity"; in addition, Al 1.5 The CoCrFeNi high-entropy alloy has high fracture toughness, which can resist the volume expansion in the battery charging and discharging cycle and avoid the peeling of the coating. Therefore, Al 1.5 The CoCrFeNi high-entropy alloy coating has good application potential in the field of battery module surface protection. In the current research, the organic flame-retardant coating (such as ammonium polyphosphate) has poor temperature resistance (<300 DEG C), the ceramic coating (such as Al2O3) has insufficient toughness and is easy to crack, and the traditional metal coating has low melting point and insufficient heat insulation performance.

[0027] The Al 1.5 The CoCrFeNi high-entropy alloy powder has a near-spherical shape, which makes the powder have good fluidity, the powder particle size is uniform, and compared with the commercial equal-atomic-ratio AlCoCrFeNi high-entropy alloy powder, the Al 1.5 The CoCrFeNi high-entropy alloy powder is better melted in the process of supersonic flame spraying, and is more strongly combined with the substrate; the substrate surface Al 1.5 The CoCrFeNi high-entropy alloy functional layer has a thickness of about 250 mu m, and the hardness can reach 723.11+ / -15 HV 0.3 ; within 25-1000 DEG C, the thermal conductivity decreases with the increase of temperature, and the functional layer is not cracked at 1000 DEG C, and the thermal conductivity at 1000 DEG C is lower than 20 W / (m·K), which greatly improves the heat insulation and fire resistance performance of the substrate at high temperature. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is an SEM image of the original surface morphology of Al, Co, Cr, Fe and Ni elemental powder;

[0029] Figure 2 It is an SEM image of the Al 1.5 CoCrFeNi high-entropy alloy powder surface morphology;

[0030] Figure 3Al produced by the step-by-step mechanical alloying process in Examples 1-5 under different ball milling times 1.5 SEM images of the cross-sectional morphology of CoCrFeNi high-entropy alloyed powder and EDS elemental distribution maps of the corresponding regions.

[0031] Figure 4 Al produced by the step-by-step mechanical alloying process in Examples 1-5 under different ball milling times 1.5 Particle size distribution and average particle size D of CoCrFeNi high-entropy alloyed powder 50 ;

[0032] Figure 5 Al prepared by the oxygen-kerosene supersonic flame spraying process in Example 6 1.5 Comparison of surface morphology between the functional layer of CoCrFeNi high-entropy alloy and the coating of AlCoCrFeNi high-entropy alloy with equal atomic ratio in Comparative Example 1.

[0033] Figure 6 Al prepared by the oxygen-kerosene supersonic flame spraying process in Example 6 1.5 SEM images of the cross-sectional morphology of the functional layer of the CoCrFeNi high-entropy alloy and corresponding EDS elemental distribution diagrams;

[0034] Figure 7 Al prepared by the oxygen-kerosene supersonic flame spraying process in Example 6 1.5 Thermal conductivity diagram of the functional layer of CoCrFeNi high-entropy alloy as a function of temperature. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] The numerical values set forth in the examples provided herein are only by way of example and should not be construed in a limiting sense. Certain aspects of the technology can not be discussed in detail if such technology is known to those of ordinary skill in the relevant art. Any reference to claim elements in the singular, can include the plural, and vice versa, unless otherwise indicated. Unless otherwise indicated, all numbers expressing quantities of materials, percentages and so forth, are to be understood as being modified in all instances by the term "about." Any numerical range recited herein is intended to include all sub-ranges subsumed therein. Warnings of "at least first amount" and "up to at least a second amount" mean that the first amount is required and that the second amount is the maximum. Thus, "at least first amount and up to at least a second amount" means that the first amount is required but that the second amount is optional. Any reference to claim elements in the singular, can include the plural, and vice versa, unless otherwise indicated. Unless otherwise indicated, all numbers expressing quantities of materials, percentages and so forth, are to be understood as being modified in all instances by the term "about." Any numerical range recited herein is intended to include all sub-ranges subsumed therein. Warnings of "at least first amount" and "up to at least a second amount" mean that the first amount is required and that the second amount is the maximum. Thus, "at least first amount and up to at least a second amount" means that the first amount is required but that the second amount is optional.

[0037] The experimental methods in the following examples without specific conditions are generally determined according to the national standards; if there is no corresponding national standard, it is determined according to the general standard requirements or general method.

[0038] Example 1

[0039] The case is a step-by-step mechanical alloying process for Al 1.5 CoCrFeNi high-entropy alloy powder, the specific operation is as follows:

[0040] (1) According to the molar ratio of elements Al:Co:Cr:Fe:Ni=1.5:1:1:1:1, weigh the elemental powder Al, Co, Cr, Fe and Ni (corresponding to atomic percentage about Al 27.27%, Cr 18.18%, Co 18.18%, Fe 18.18%, Ni 18.19%), and calculate the total mass of these elemental powders, the micro-morphology of each powder is shown in Figure 1

[0041] (2) Pour the weighed elemental powders Co, Cr, Fe and Ni into the ball mill tank, add grinding balls in the ball mill tank, select grinding balls with diameters of 15mm, 10mm, 6mm and 5mm, and mix them according to the mass ratio of 1:4:2:1, the total mass of the grinding balls and the total mass of the elemental powders is in the proportion of 15:1; then seal the ball mill tank, and perform vacuumization in the tank body to below 10Pa and keep for 10min, then fill in argon with purity of at least 4N to the tank body pressure of 0.5MPa for protection for 10min.

[0042] (3) Place the ball mill tank in the full-range planetary ball mill, set the ball milling speed to 300rpm, run for 10min, stop for 2min, reverse for 10min, stop for 2min as one cycle, and carry out the first stage ball milling for 20h.

[0043] ​(4) After the first stage ball milling, open the ball milling jar to pour in the weighed elemental powder Al, and seal, vacuumize and argonize the ball milling jar as in step (2), then put the ball milling jar into the planetary ball mill, set the ball milling speed to 220 rpm, and run for 10 min in forward direction, stop for 2 min, run for 10 min in reverse direction, stop for 2 min as one cycle, and then carry out the second stage ball milling for 40 h.

[0044] (5) After the ball milling time is reached, take out the alloyed powder, and sieve the powder using a powder sieve and a metal sieve net equipped with an ultrasonic vibrator, in which the upper metal sieve net is 325 mesh and the lower metal sieve net is 800 mesh, the ultrasonic vibrator is installed on the lower metal sieve net, and the sieving time is 30 min; finally, Al 1.5 CoCrFeNi high-entropy alloyed powder is obtained in the lower sieve net with a particle size range of 15-45 μm.

[0045] Example 2

[0046] This case is a case of preparing Al 1.5 CoCrFeNi high-entropy alloyed powder by step-by-step mechanical alloying process, and the specific process is the same as that of Example 1, except that the second stage ball milling time in step (4) is 30 h.

[0047] Example 3

[0048] This case is a case of preparing Al 1.5 CoCrFeNi high-entropy alloyed powder by step-by-step mechanical alloying process, and the specific process is the same as that of Example 1, except that the second stage ball milling time in step (4) is 35 h.

[0049] Example 4

[0050] This case is a case of preparing Al 1.5 CoCrFeNi high-entropy alloyed powder by step-by-step mechanical alloying process, and the specific process is the same as that of Example 1, except that the second stage ball milling time in step (4) is 45 h.

[0051] Example 5

[0052] This case is a case of preparing Al 1.5 CoCrFeNi high-entropy alloyed powder by step-by-step mechanical alloying process, and the specific process is the same as that of Example 1, except that the second stage ball milling time in step (4) is 50 h.

[0053] The Al 1.5The CoCrFeNi high-entropy alloying powder was observed by SEM on the powder surface and cross-section, the surface morphology is shown in Figure 2 , the cross-section morphology is shown in Figure 3 , and the particle size distribution of the powder was measured by a laser particle size analyzer, as shown in Figure 4 .

[0054] As can be seen from Figure 2 , when the ball milling time is 30 h-35 h, the plastic powder deforms and the brittle powder gradually breaks. Since the ball milling time is relatively short at this time, the cold welding effect dominates during ball milling, and slight agglomeration occurs between the powder particles. The agglomerated powder particles are irregular polygons, and the particle size of some agglomerated powder particles even exceeds the original powder particle size. Moreover, the size difference between different particles is still large. When the ball milling is to 40 h, under the impact of the grinding balls, the agglomerated powder particles break, the powder particle size decreases, and the particle size difference between large particles and small particles also decreases. The originally irregular polygon-shaped large particles also become smaller near-spherical particles (c) of Figure 2 . The composite powder becomes more uniform. When the ball milling is to 45 h-50 h, the powder particles agglomerated due to cold welding in the early stage of ball milling are broken into smaller particles, and the powder particle size is still decreasing (d) of Figure 2 . When the ball milling time reaches 50 h, the powder particles are further refined, the small size powder increases, and the particle size difference between different powder particles becomes larger and larger. At the same time, the number of irregular polygon-shaped powder particles increases (e) of Figure 2 . Generally speaking, the mechanical alloying of metal powder is an alternating process of cold welding and breaking. The alloy powder continuously undergoes cold welding, breaking, re-cold welding, and re-breaking under the repeated action of the grinding balls. At this time, the powder particles have a regular spherical shape and uniform size, the powder particle size is not more than 45 μm, and mainly distributed at 35 μm. Figure 3 The cross-section morphology and EDS analysis of the composite powder after different ball milling times, there are many Fe, Cr, Ni, Co enrichment areas in the microstructure when ball milling for 30 h and 35 h, the alloying degree is low. These areas are mainly flaky structure. After shearing deformation when ball milling for 40 h, the Fe, Cr, Ni, Co enrichment areas are obviously refined and dispersed, forming fine filaments, indicating that the element dissolution is more uniform. The shearing refinement and dispersion of Fe, Cr and Ni rich regions under high speed collision are significant, which accelerates the diffusion and dissolution of elements. When ball milling for 45 h and 50 h, Fe, Co, Cr enrichment areas are formed again due to the dominant role of breaking. Figure 4 The particle size distribution, D 50 variation trend of different ball milling times, in Figure 4It can be seen from (a) that with the increase of ball milling time, the particle size distribution curve shows a trend of first increasing and then decreasing. The powder particle size gradually increases at 35 h, and the powder particle size gradually increases at 40 h. The average particle size (D 50 =37.57 µm) of the powder after 40 h, and the D 50 starts to decrease, indicating that the powder crushing dominates at 45 h and 50 h. Therefore, the second stage ball milling time of 40 h is the best process for the high-entropy alloying powder Al 1.5 CoCrFeNi.

[0055] Example 6

[0056] The case is a preparation method of a substrate with heat insulation function, comprising the following steps:

[0057] S1, using detergent powder, alcohol and acetone to remove oil and purify the surface of the battery module (such as the box body) Q235 substrate, then performing sand blasting roughening treatment on the surface after oil removal, the sand blasting material is brown corundum sand (Al2O3) with a particle size of 60 mesh, the sand blasting pressure is adjusted to 0.3 MPa, and the surface roughness Ra of the Q235 substrate after sand blasting reaches 2.5 μm;

[0058] S2, using the Al 1.5 CoCrFeNi high-entropy alloying powder prepared in Example 1 as the functional layer material to perform oxygen-kerosene supersonic flame spraying on the Q235 substrate after sand blasting, and the specific operation is as follows:

[0059] Turn on the power supply, gas valve and cooling water switch of the spraying equipment, use oxygen as the combustion aid, kerosene as the fuel, argon as the powder feeding carrier gas, and air as the cooling medium, fix the sample on the workbench, set the running program of the mechanical arm, the spraying distance is 350 mm, the spraying speed is 800 mm / s, and the spraying step is 3 mm;

[0060] Open the kerosene, oxygen and air flow valves, adjust the oxygen flow rate to 15 L / h, the kerosene flow rate to 32 L / h, and the air flow rate to 350 L / min, ignite the kerosene flame to preheat the surface of the substrate to a temperature of 80-120℃, open the powder feeder switch, adjust the powder feeding voltage to 3.3 V, and spray at a powder feeding rate of 32 g / min; after spraying for 4 times, use compressed air to blow and cool the surface of the coating, and use a screw micrometer to measure the thickness of the sprayed functional layer. When the temperature of the functional layer is reduced to below 60℃, start the spraying equipment to continue spraying, and repeat the operation to finally make the thickness of the sprayed functional layer reach about 250 μm.

[0061] Example 7

[0062] The substrate treatment method of this case is the same as that of Example 6, except that the spraying material is Al 1.5 CoCrFeNi high-entropy alloy powder.

[0063] Example 8

[0064] The substrate treatment method of this case is the same as that of Example 6, except that the spraying material is Al 1.5 CoCrFeNi high-entropy alloy powder.

[0065] Example 9

[0066] The substrate treatment method of this case is the same as that of Example 6, except that the spraying material is Al 1.5 CoCrFeNi high-entropy alloy powder.

[0067] Example 10

[0068] The substrate treatment method of this case is the same as that of Example 6, except that the spraying material is Al 1.5 CoCrFeNi high-entropy alloy powder.

[0069] Comparative Example 1

[0070] The substrate treatment method of this case is the same as that of Example 6, except that the spraying material is a commercial equiatomic AlCoCrFeNi high-entropy alloy powder with a particle size of 10-53 μm (corresponding to an atomic percentage of each element of 20%).

[0071] Comparative Example 2

[0072] The substrate treatment method of this case is the same as that of Example 6, except that the spraying material is an Al2CoCrFeNi high-entropy alloy powder, which is prepared in the same manner as in Example 1, except that the molar ratio of each element is Al:Co:Cr:Fe:Ni = 2:1:1:1:1 (corresponding to an atomic percentage of about Al 33.3%, Cr 16.7%, Co 16.7%, Fe 16.7%, and Ni 16.6%).

[0073] Test Example

[0074] The microstructure and performance of the substrates with high-entropy alloy functional layers prepared in Example 6 and Comparative Example 1 were tested: the surface of the substrate with the high-entropy alloy functional layer was observed using SEM; the microhardness of the two substrates with the high-entropy alloy functional layer was measured using a Vickers hardness tester, the load was 2.94 N, the loading time was 15 s, 15 points of each coating were tested, and the average value was taken as the microhardness value of the functional layer; the thermal conductivity of the substrate with the high-entropy alloy functional layer was measured using a laser thermal conductivity performance tester. The results are shown in Table 1 and Figures 5-7 .

[0075] Table 1 Microhardness and thermal conductivity of various high-entropy alloy functional layers

[0076]

[0077] As can be seen from Table 1, compared with the commercial AlCoCrFeNi powder sprayed coating, the microhardness of the stepwise mechanical alloying AlCoCrFeNi powder sprayed coating is significantly improved. Because the strong plastic deformation and dislocation multiplication during mechanical alloying lead to a significant reduction in grain size. According to the Hall-Petcch relationship, the smaller the grain size, the higher the grain boundary density, and the stronger the ability to hinder dislocation movement, thereby improving the hardness. 1.5

[0078] The surface micro-morphology of the substrates with the high-entropy alloy functional layer of Example 6 and Comparative Example 1 is shown in Figure 5 . Figure 5 (a) is the substrate with the AlCoCrFeNi high-entropy alloy functional layer prepared in Example 6, and 1.5 (b) is the substrate with the AlCoCrFeNi high-entropy alloy functional layer prepared in Comparative Example 1. 1.5 The AlCoCrFeNi high-entropy alloying powder reaches the surface of the substrate at high temperature, is fully melted, and almost no complete particles can be seen on the surface of the coating, indicating that the degree of powder melting during the supersonic flame spraying process is good. However, in Figure 5 (b) of the commercial AlCoCrFeNi high-entropy alloy powder, compared with the spraying effect on the steel substrate, there are still some large particles on the substrate that are not fully melted, which may be caused by the poor combination of the powder and the substrate.

[0079] The thermal conductivity of Example 6 as a function of temperature is shown in Figure 7 . Compared with the traditional thermal barrier coating, the substrate with the AlCoCrFeNi high-entropy alloy functional layer prepared in Example 6 has a lower thermal conductivity as the temperature rises, and the functional layer does not crack during the 1000 ℃ test, and the thermal conductivity is as low as about 15.50 W / (m·K) at 1000 ℃, which makes the substrate with the AlCoCrFeNi high-entropy alloy functional layer have good thermal barrier properties. 1.5 1.5 ​​​

[0080] Low thermal conductivity coating-substrate composite structure as a key component material of battery module shows multiple advantages. The substrate with Al 1.5 The substrate of CoCrFeNi high-entropy alloy functional layer can effectively delay heat transfer and prevent thermal runaway diffusion through its unique heat insulation performance, and the decreasing characteristics of thermal conductivity at 25-1000℃ further enhance the heat protection effect, and has the characteristics of structural and functional integration. The lattice distortion generated by the substrate improves the mechanical strength while optimizing the heat insulation performance. In addition, the optimized thermal expansion coefficient matching scheme (such as a steel substrate) ensures the interface bonding strength, maintains the structural stability while realizing controllable thermal management. The substrate with Al 1.5 The substrate of CoCrFeNi high-entropy alloy functional layer is particularly suitable for high-energy density battery systems, and the pressure release channel design and positive feedback protection mechanism provide double protection for battery safety. The current research focuses on balancing material pore distribution and mechanical reliability to further improve its comprehensive performance.

[0081] In summary, the substrate with Al 1.5 The substrate of CoCrFeNi high-entropy alloy functional layer meets the heat insulation requirements of the battery module, and the best powder and coating preparation process is obtained by improving the process flow. The Al 1.5 CoCrFeNi high-entropy alloy powder is prepared by a step-by-step mechanical alloying process, and the spraying process parameters are as follows: kerosene flow rate is 32 L / h, oxygen flow rate is 15 L / h, air flow rate is 350 L / min, spraying distance is 350 mm, spraying step distance is 3 mm, spraying speed is 800 mm / s, powder feeding voltage is 3.3 V, and powder feeding rate is 32 g / min. The coating prepared under the above parameters has high hardness and low thermal conductivity at high temperature.

[0082] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for producing a substrate having a heat-insulating function, characterized by, It comprises the following steps: S1, after the surface of the metal substrate is cleaned and treated, roughening treatment is performed to obtain a pretreated substrate, which is preheated for use; S2, high-entropy alloy powder prepared by step-by-step mechanical alloying is sprayed onto the surface of the preheated pretreated substrate, to obtain a substrate with heat insulation function; The high-entropy alloy powder is composed of the following atomic percentage elements: Al 25%-30%, Co 17%-20%, Cr 17%-20%, Fe 17%-20%, and Ni 17%-20%. The high-entropy alloy powder is composed of the following atomic percentage elements:

2. The method of claim 1, wherein the substrate having a thermal barrier function is prepared by the steps of: Al 26%-29%, Co 17.5%-19%, Cr 17.5%-19%, Fe 17.5%-19%, and Ni 17.5%-19%. The step-by-step mechanical alloying is to first mix and ball mill the elemental powders Cr, Co, Fe, and Ni according to the ratio, and then further ball mill the elemental powder Al to obtain an alloy powder with an average particle size of 20-40 microns. The specific method of the step-by-step mechanical alloying is as follows:

3. The method of claim 2, wherein the method further comprises the step of applying a coating to the substrate. The elemental powders Cr, Co, Fe, and Ni are weighed according to the ratio, then poured into a ball mill tank, and then added with grinding beads, sealed, vacuumed, and filled with argon, and then placed in a planetary ball mill at a speed of 250-500 rpm for the first stage of ball milling for 15-25 h, then the formula amount of elemental powder Al is added in the ball mill tank, and then sealed, vacuumed, and filled with argon again, and then placed in a planetary ball mill at a speed of 200-250 rpm for the second stage of ball milling for 30-50 h.

4. The method of claim 3, wherein the method further comprises the step of applying a coating to the substrate. The specific operation of vacuuming and filling with argon is as follows: the inside of the ball mill tank is vacuumed to below 10 Pa and maintained for 10 min, and then at least 4N pure argon is introduced into the tank to a pressure of 0.5 MPa for protection for 10 min; Grinding beads with ball diameters of 15 mm, 10 mm, 6 mm, and 5 mm are configured in a mass ratio of 1:4:2:1, and the total weight of the grinding beads and the total weight of the elemental powders are mixed in a ratio of 10-20:1; 5. The method for preparing a substrate with heat insulation function according to claim 4, characterized in that, One cycle of the planetary ball mill operation is set as follows: forward rotation for 10 min, stop for 2 min, reverse rotation for 10 min, and stop for 2 min. The high-entropy alloy powder is composed of the following elements Al, Cr, Co, Fe, and Ni in a molar ratio of 1.5:1:1:1:1; the first stage of ball milling is for 20 h, and the second stage of ball milling is for 40-50 h. In S2, the spraying is performed by oxygen-kerosene supersonic flame spraying, using oxygen as the combustion aid, kerosene as the fuel, argon as the powder feeding carrier gas, and air as the cooling medium, and the spraying parameters are as follows: oxygen flow rate is 15 L / h, kerosene flow rate is 32 L / h, air flow rate is 350 L / min, spraying step distance is 3 mm, spraying speed is 800 mm / s, powder feeding voltage is 3.3 V, and powder feeding rate is 32 g / min.

6. The method for preparing a substrate with heat insulation function according to claim 4, characterized in that, In S1, the roughening treatment is sand blasting roughening of the surface, and the sand blasting pressure is 0.3-0.5 MPa, and the surface roughness of the substrate after sand blasting is 2.5-3 microns.

7. A method for preparing a heat-insulating substrate according to any one of claims 1-6, characterized in that, ​ 8. The method of claim 1-6, wherein the method further comprises the step of applying a coating to the substrate. 5 ​ The preheating temperature in S1 reaches 80-120℃; The metal substrate is selected from one of aluminum alloy, magnesium alloy, steel.

9. The method of manufacturing a substrate having a thermal barrier function according to any one of claims 1 to 8, characterized in that, The metal substrate surface has a thermal insulation functional layer, and the material of the thermal insulation functional layer is Al 1.5 CoCrFeNi high-entropy alloy, the functional layer has a thickness of 200-300 microns and a hardness of 700-800 HV 0.3 , and the thermal conductivity at 1000℃ is lower than 20 W / (m·K).

10. Use of the substrate with thermal insulation function obtained by the preparation method according to any one of claims 1-8 for surface protection in energy storage batteries.

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