Aluminum alloy for battery water cooling plate and method for manufacturing the same

Abstract

The application relates to an aluminum alloy for a battery water cooling plate and a preparation method thereof, which comprises the following materials in percentage by mass: Ni 4-6%, Mn 0.4-0.6%, Fe 0.4-0.8%, Si 0.5-0.8%, Mo 0.5-0.8%, Zr 0.2-0.3%, the balance being aluminum and inevitable impurity elements, the content of each impurity element being less than or equal to 0.1%, and the total content of the impurity elements being less than or equal to 0.3%. The application further improves the high-temperature strength of the alloy by innovatively introducing an AlFeMoSi quaternary high-temperature stable phase, the melting point of the precipitated phase is greater than 600 DEG C, the high-temperature welding process is not affected, meanwhile, the addition of Mo consumes part of Fe and Si elements, the allowable amount of the Fe and Si elements in the alloy is increased, and the casting alloy cost is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloys, and more particularly to an aluminum alloy for battery water cooling plates and its preparation method. Background Technology

[0002] With the rapid development of new energy vehicles in my country, higher requirements have been placed on battery systems. As driving mileage increases, higher demands are placed on battery cooling systems. The battery cooling system of new energy vehicles mainly includes important components such as the battery, battery cooler, and water-cooled plate. The water-cooled plate, made of aluminum alloy, is primarily connected by high-temperature brazing of two aluminum plates. Currently, the most widely used are 3000 series and 6000 series wrought aluminum alloys, prepared through forging and rolling, which have long production cycles, high processing costs, and low material utilization, failing to meet the rapidly growing production demands. Furthermore, wrought alloys require strict control over impurity elements such as Fe and Si, further increasing product costs. In contrast, traditional cast aluminum alloys, represented by Al-Si, Al-Cu, and Al-Mg alloys, offer excellent casting performance and short production cycles, significantly reducing costs. However, when brazing temperatures reach 580-600℃, the intermediate phase of cast aluminum alloys has a low melting point. Prolonged immersion in the high-temperature brazing bath can lead to overheating and remelting, resulting in blistering defects and damaging the product structure. If water-cooled plate materials can be formed through casting, the production cycle and cost can be greatly reduced, meeting the urgent needs of new energy vehicle battery systems, and there will be a very broad market demand in the future. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the aforementioned problems in the prior art, this invention provides an aluminum alloy for battery water-cooling plates and a method for preparing the same.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0007] An aluminum alloy for battery water cooling plates is characterized by comprising the following materials by mass percentage: Ni 4-6%, Mn 0.4-0.6%, Fe 0.4-0.8%, Si 0.5-0.8%, Mo 0.5-0.8%, Zr 0.2-0.3%, with the balance being aluminum and unavoidable impurity elements, each impurity element having a content ≤0.1%, and the total amount of impurity elements ≤0.3%.

[0008] Furthermore, the mass ratio of Mn to Fe is Mn:Fe = 0.5-1:1, and the total mass percentage of Mn and Fe, Mn+Fe ≤ 1.2%.

[0009] Furthermore, the mass ratio of Mo to Si is Mo:Si = 0.9-1.1:1.

[0010] A method for preparing an aluminum alloy for a battery water-cooling plate, characterized by comprising the following steps:

[0011] S1: Smelting: Aluminum ingots and other intermediate alloys are added in sequence. After complete melting, refining is carried out to obtain pure aluminum alloy melt.

[0012] S2: Rheological die casting: The aluminum alloy melt is fed into the die casting machine barrel through a tilted, rotatable open crucible for temperature control to prepare a rheological slurry, which is then directly die cast to obtain aluminum alloy sheet material.

[0013] Furthermore, the temperature of the aluminum alloy melt after passing through the open crucible is 580-620℃, and the corresponding mass percentage of the pre-precipitated solid phase is 20-40%.

[0014] Furthermore, the temperature of the aluminum alloy melt before passing through the open crucible is 680-720℃.

[0015] Furthermore, the tilt angle of the open crucible is 30-60°.

[0016] Furthermore, the inner wall of the open crucible includes spaced protrusions; the height of the protrusions is 3-15mm, and the interval between adjacent protrusions is 30-50mm.

[0017] Furthermore, the protrusion is equipped with a thermocouple for monitoring real-time temperature.

[0018] Furthermore, the rotational speed of the open crucible is 50-150 rpm.

[0019] (III) Beneficial Effects

[0020] The beneficial effects of this invention are:

[0021] 1. The aluminum alloy material for water-cooled plates in new energy vehicle batteries provided by this invention introduces the highly thermally stable AlFeMoSi quaternary phase, resulting in excellent thermal stability and preventing overheating and remelting during subsequent brazing. Simultaneously, the formation of the Mo phase consumes Fe and Si impurity phases, increasing the allowable Fe and Si content. In this invention, the Fe and Si impurities can be relatively high because they do not form low-melting-point phases. Higher Fe and Si elements form the high-melting-point AlFeMoSi phase, and the increased Fe element content reduces the problem of material sticking to the mold. Furthermore, the addition of Si helps improve alloy fluidity and reduce casting defects. In addition, the addition of Zr helps refine the matrix structure. This invention also introduces a slanted tube rheological die-casting process, which, through precise temperature field control, obtains a uniform slurry structure, effectively reducing defects after die-casting and ensuring a smooth brazing process.

[0022] 2. The Ni content in the alloy material is between 4-6% to ensure the fluidity of the alloy.

[0023] 3. In the alloy material, the mass ratio of Mn to Fe is between 0.5 and 1.0, and Mn+Fe≤1.2%. Increasing the allowable amount of Fe in the alloy reduces the cost of the alloy and also reduces the tendency of the alloy to stick to the mold. In the alloy material, the mass percentage of Mo to Si is between 0.9 and 1.1, which promotes the formation of AlFeMoSi phase and significantly improves the high-temperature strength of the alloy. At the same time, the increase in Si content improves the fluidity of the alloy, but does not generate a low-melting-point eutectic Si phase.

[0024] 4. The inner wall of the open crucible is composed of a wavy surface. The wavy surface helps to dissipate heat from the melt and regulate the structure of the primary solid phase, thereby obtaining a slurry structure with uniform primary phase size.

[0025] 5. After the melt passes through the inner wall of the open crucible, the slurry temperature is 580-620℃, and the corresponding mass percentage of the pre-precipitated solid phase is 20-40%. The solid fraction of the rheology slurry is accurately controlled by controlling the pouring temperature and the slurry temperature at the end of the open crucible. By controlling the pouring temperature and real-time temperature measurement of different protrusions of the open crucible, the crucible rotation speed is increased when the temperature is too high, thereby ensuring that the slurry temperature at the end of the crucible is between 580-620℃, thus achieving accurate slurry temperature control.

[0026] 6. Multiple thermocouples can measure the temperature of the melt in the open crucible in real time, and the heat dissipation process can be changed by rotating the inclined tube, thereby achieving dynamic temperature control and ensuring the uniformity of the slurry.

[0027] 7. Thin-walled products prepared using the material composition and rheological die casting method of this invention effectively reduce the tendency to stick to the mold, increase the yield, and reduce defects such as air entrapment during the die casting process through the rheological die casting method, achieving near-net-shape forming and allowing for direct high-temperature brazing. Compared with current deformable materials, the machining workload is small, improving material utilization and significantly increasing productivity, making it a promising candidate for application in the rapidly growing new energy vehicle sector. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the rheological slurry preparation and die casting process using the inclined tube method of the present invention;

[0030] Figure 2 This is a thermodynamic calculation of the phase composition and precipitation temperature diagram of the alloy when the composition is Al-4Ni-0.5Mn-0.7Fe-0.5Si-0.5Mo-0.2Zr. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1:

[0033] An aluminum alloy material for water-cooling plates in new energy vehicle batteries has the following specific composition: Al-4Ni-0.5Mn-0.7Fe-0.5Si-0.5Mo-0.2Zr. Other individual impurity elements are controlled to below 0.1%, and the total amount of other impurity elements is controlled to below 0.3%. It is formed using the inclined tube rheo-die casting method. Figure 1As shown, the alloy melt 110 in the ladle 100 is poured into an inclined open crucible 200. The inclination angle of the open crucible 200 is 30 degrees. The height of the protrusions 210 is 3 mm, and the spacing between the protrusions 210 is 30 mm. The protrusions 210 are approximately hemispherical and are equipped with thermocouples 220 for monitoring real-time temperature. The slurry temperature at the end of the open crucible 200 is 610-620℃ as it flows into the barrel 300 to complete the preparation of the rheological slurry. Subsequently, it is die-cast to obtain a rheological die-cast sheet 400. The rheological die-cast product prepared by the above method has a dense structure, no casting cracks, and no blistering defects when brazed at high temperatures above 600℃.

[0034] Example 2:

[0035] An aluminum alloy material for water-cooled plates in new energy vehicle batteries has the following specific composition: Al-5Ni-0.4Mn-0.8Fe-0.8Si-0.72Mo-0.25Zr. Other individual impurity elements are controlled to be below 0.1%, and the total amount of other impurity elements is controlled to be below 0.3%. It is formed using a rheo-die casting method with an inclined tube. The structure and arrangement of the open crucible 200 are the same as in Example 1. Preparation is completed by maintaining the slurry temperature at the end of the open crucible 200 at 590-600℃, followed by die casting. The rheo-die-cast product prepared by the above method has a dense microstructure, is free of casting cracks, and exhibits no blistering defects when brazed at temperatures above 600℃.

[0036] Example 3:

[0037] An aluminum alloy material for water-cooled plates in new energy vehicle batteries has the following specific composition: Al-5Ni-0.4Mn-0.4Fe-0.6Si-0.54Mo-0.3Zr. Other individual impurity elements are controlled to be below 0.1%, and the total amount of other impurity elements is controlled to be below 0.3%. It is formed using a rheo-die casting method with an inclined tube. The structure and arrangement of the open crucible 200 are the same as in Example 1. Preparation is completed by maintaining the slurry temperature at the end of the open crucible 200 at 595-605℃, followed by die casting. The rheo-die-cast product prepared by the above method has a dense microstructure, is free of casting cracks, and exhibits no blistering defects when brazed at temperatures above 600℃.

[0038] Example 4:

[0039] An aluminum alloy material for water-cooled plates in new energy vehicle batteries has the following specific composition: Al-5.5Ni-0.6Mn-0.6Fe-0.77Si-0.7Mo-0.25Zr. Other individual impurity elements are controlled to below 0.1%, and the total amount of other impurity elements is controlled to below 0.3%. It is formed using a rheo-die casting method with an inclined tube. The structure and arrangement of the open crucible 200 are the same as in Example 1. Preparation is completed by maintaining the slurry temperature at the end of the open crucible 200 at 600-610℃, followed by die casting. The rheo-die-cast product prepared by the above method has a dense microstructure, is free of casting cracks, and exhibits no blistering defects when brazed at temperatures above 600℃.

[0040] Example 5:

[0041] An aluminum alloy material for water-cooled plates in new energy vehicle batteries has the following specific composition: Al-6Ni-0.5Mn-0.5Fe-0.8Si-0.8Mo-0.2Zr. Other individual impurity elements are controlled to be below 0.1%, and the total amount of other impurity elements is controlled to be below 0.3%. It is formed using a rheo-die casting method with an inclined tube. The structure and arrangement of the open crucible 200 are the same as in Example 1. Preparation is completed when the slurry temperature at the end of the open crucible 200 is 580-590℃, followed by die casting. The rheo-die-cast product prepared by the above method has a dense microstructure, no casting cracks, and no blistering defects when brazed at temperatures above 600℃.

[0042] The chemical composition test results of the above embodiments are shown in Table 1 below:

[0043] Table 1

[0044]

[0045] The experimental results of the above embodiments are analyzed in Table 2 below:

[0046] Table 2

[0047]

[0048]

[0049] The phase composition and precipitation temperature of the alloy in different embodiments are further analyzed below:

[0050] According to calculations, within the material composition range of this invention, the precipitation temperatures of the generated AlFeMoSi, Al3Ni, and α-Fe phases are all above 600℃, ensuring that remelting and overheating do not occur during subsequent brazing. Simultaneously, the Mn and Fe content in this invention significantly reduces the alloy's tendency to stick to the mold. The presence of the AlFeMoSi quaternary phase can consume some of the impurities Si and Fe, and this phase has high thermal stability, ensuring the alloy's high-temperature strength. Furthermore, the inclined tube rheo-die casting method is used for casting. Through special design of the inner wall of the tube and precise control of the temperature field, the slurry composition becomes more uniform, and the slurry is directly transferred into the die-casting machine barrel for die casting, eliminating heat loss during the transfer process. The slurry is then pushed into the die-casting machine barrel for die casting, resulting in a material without significant casting defects.

[0051] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An aluminum alloy for a battery water-cooling plate, characterized in that, The composition includes the following materials by mass percentage: Ni 4-6%, Mn 0.4-0.6%, Fe 0.4-0.8%, Si 0.5-0.8%, Mo 0.5-0.8%, Zr 0.2-0.3%, with the balance being aluminum and unavoidable impurity elements, each impurity element being ≤0.1%, and the total amount of impurity elements being ≤0.3%. The mass ratio of Mn to Fe is Mn:Fe = 0.5-1:1, and the total mass percentage of Mn and Fe, Mn+Fe ≤ 1.2%; The mass ratio of Mo to Si is Mo:Si = 0.9-1.1:

1.

2. A method for preparing an aluminum alloy for a battery water-cooling plate as described in claim 1, characterized in that, Includes the following steps: S1: Smelting: Aluminum ingots and other intermediate alloys are added in sequence. After complete melting, refining is carried out to obtain pure aluminum alloy melt. S2: Rheological die casting: The aluminum alloy melt is fed into the die casting machine barrel through a tilted, rotatable open crucible for temperature control to prepare a rheological slurry, which is then directly die-cast to obtain aluminum alloy sheet material. The temperature of the aluminum alloy melt after passing through the open crucible is 580-620℃, and the corresponding mass percentage of the pre-precipitated solid phase is 20-40%. The temperature of the aluminum alloy melt before passing through the open crucible is 680-720℃.

3. The method for preparing an aluminum alloy for a battery water-cooling plate according to claim 2, characterized in that: The tilt angle of the open crucible is 30-60°.

4. The method for preparing an aluminum alloy for a battery water-cooling plate according to claim 2, characterized in that: The inner wall of the open crucible includes spaced protrusions; the height of the protrusions is 3-15mm, and the interval between adjacent protrusions is 30-50mm.

5. The method for preparing an aluminum alloy for a battery water-cooling plate according to claim 4, characterized in that: The protrusion contains a thermocouple for monitoring real-time temperature.

6. The method for preparing an aluminum alloy for a battery water-cooling plate according to claim 2, characterized in that: The rotational speed of the open crucible is 50-150 rpm.

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