Aluminum alloy and preparation method thereof, liquid cooling plate, battery and electric equipment

Abstract

The invention discloses an aluminum alloy and a preparation method thereof, a liquid cooling plate, a battery and electric equipment, and the aluminum alloy comprises the following components in percentage by mass: 0.75%-0.9% of Mn, 0.30%-0.36% of Fe, 0.18%-0.23% of Si and the balance of Al and inevitable impurities; wherein in the aluminum alloy, the mass ratio of Fe to Si is a, and a is smaller than or equal to 2. The aluminum alloy provided by the invention has excellent extrusion processing performance and elongation.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum alloys, and in particular to an aluminum alloy and a preparation method thereof, a liquid cooling plate, a battery and electrical equipment. Background Art

[0002] Aluminum alloys are widely used in people's production and life. For example, in the battery field, a liquid cooling plate is usually used between two battery cells for heat dissipation, and such liquid cooling plates often use aluminum alloys.

[0003] However, existing aluminum alloys have poor extrusion processing performance and low elongation.

[0004] Public Content

[0005] In view of the technical problems existing in the background technology, the present application provides an aluminum alloy, aiming to solve the problems of poor extrusion processing performance and low elongation of the aluminum alloy.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present application provides an aluminum alloy, which, in terms of mass percentage, includes 0.75%-0.9% Mn, 0.30%-0.36% Fe, 0.18%-0.23% Si, and the remainder is Al and unavoidable impurities; wherein, in the aluminum alloy, the mass ratio of the Fe to the Si is a, a≤2.

[0007] The present application at least includes the following beneficial effects: in the aluminum alloy of the present application, the mass percentages of manganese, iron and silicon are controlled, and the mass ratio of Fe to Si is controlled. On the one hand, the existence form of Mn in the aluminum alloy can be adjusted so that Mn has a suitable solid solution strengthening effect, the extrusion processing performance of the aluminum alloy is improved, the extrusion production efficiency and the die life are improved, the processing cost is reduced, and the aluminum alloy has excellent strength. On the other hand, the second phase of the aluminum alloy can be promoted to form α-Al 12 (Fe, Mn)3Si, reducing the brittle phase β-Al 85 (Mn, Fe) 14 The formation of Si, α-Al 12 (Fe, Mn)3Si is distributed in the aluminum alloy, which can promote recrystallization and refine the grains, thereby improving the deformation resistance of the aluminum alloy and increasing the elongation.

[0008] In some embodiments of the present application, a=1.3-2, optionally, a=1.4-1.9. This can promote the formation of α-Al as the second phase of the aluminum alloy. 12 (Fe, Mn)3Si reduces the formation of brittle phase and can improve the extrusion processing performance and elongation of aluminum alloy.

[0009] In some embodiments of the present application, the aluminum alloy includes, by mass percentage, 0.75%-0.85% Mn, 0.30%-0.34% Fe, 0.18%-0.21% Si, and the balance is Al and inevitable impurities; alternatively, by mass percentage, the aluminum alloy includes 0.75%-0.8% Mn, 0.30%-0.34% Fe, 0.18%-0.21% Si, and the balance is Al and inevitable impurities, thereby promoting the formation of α-Al as the second phase of the aluminum alloy. 12 (Fe, Mn)3Si reduces the formation of brittle phase and can improve the extrusion processing performance and elongation of aluminum alloy.

[0010] In some embodiments of the present application, the aluminum alloy further comprises, by mass percentage, at least one of (1) to (3):

[0011] (1) 0.05%-0.1% Cu;

[0012] (2) 0.001%-0.1% Zn, optionally 0.001%-0.03% Zn;

[0013] (3) 0.001%-0.05% Ti, optionally 0.01%-0.03% Ti.

[0014] Therefore, the aluminum alloy also includes the above-mentioned content of substances, which can improve the extrusion processing performance and elongation of the aluminum alloy, and the aluminum alloy has excellent strength.

[0015] The second aspect of the present application provides a method for preparing the aluminum alloy according to the first aspect, comprising:

[0016] The aluminum alloy raw material is smelted and cast to obtain a blank;

[0017] The preform is homogenized and cooled to obtain an aluminum alloy.

[0018] Therefore, the aluminum alloy prepared in the present application has good extrusion processing performance and high elongation.

[0019] In some embodiments of the present application, the temperature of the homogenization treatment is 600°C-610°C, and the time of the homogenization treatment is greater than or equal to 10 hours, and can be 10 hours-11 hours. Therefore, within the temperature and time range of the homogenization treatment, the extrusion processing performance and elongation of the aluminum alloy can be improved.

[0020] In some embodiments of the present application, the smelting process includes: melting, refining, degassing, and deslagging;

[0021] The refining temperature is 680°C-760°C, and can be optionally 730°C-760°C. Within the above refining temperature range, impurity elements in the aluminum alloy can be removed, defects such as pores, slag inclusions, and looseness in the aluminum alloy can be reduced, and the extrusion processing performance and elongation of the aluminum alloy can be improved.

[0022] In some embodiments of the present application, the refining pressure is 0.1Mpa-0.25Mpa, and can be optionally 0.2Mpa-0.25Mpa. Within the above refining pressure range, impurity elements in the aluminum alloy can be removed, thereby improving the extrusion processing performance and elongation of the aluminum alloy.

[0023] In some embodiments of the present application, the cooling treatment includes air cooling. The slow cooling speed of air cooling can reduce the shrinkage deformation of the aluminum alloy during cooling, reduce the hardening degree of the aluminum alloy surface, reduce deformation, and improve the extrudability of the aluminum alloy.

[0024] In some embodiments of the present application, the air cooling rate is 150°C / h-170°C / h, and can be 150°C / h-160°C / h. Within the above cooling rate range, the shrinkage deformation of the aluminum alloy during cooling can be reduced, the surface hardening degree can be reduced, the elongation can be increased, and the extrudability of the aluminum alloy can be improved.

[0025] A third aspect of the present application provides a liquid cooling plate, comprising the aluminum alloy described in the first aspect of the present application or the aluminum alloy prepared by the preparation method described in the second aspect.

[0026] A fourth aspect of the present application provides a battery, which includes the liquid cooling plate described in the third aspect of the present application.

[0027] A fifth aspect of the present application provides an electrical device, which includes the battery described in the fourth aspect.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0030] Figure 1 is a schematic structural diagram of a liquid cooling plate according to an embodiment of the present application;

[0031] Figure 2 yes Figure 1 A cross-section of the harmonica pipe in ;

[0032] Figure 3 is a schematic structural diagram of a battery according to one embodiment of the present application;

[0033] Figure 4 is a schematic structural diagram of a battery module according to an embodiment of the present application;

[0034] Figure 5 is a schematic structural diagram of a battery pack according to an embodiment of the present application;

[0035] Figure 6 yes Figure 5 Exploded diagram of

[0036] Figure 7 It is a schematic diagram of an embodiment of an electric device in which a battery is used as a power source.

[0037] Description of reference numerals:

[0038] 1: Secondary battery; 2: Battery module; 3: Battery pack; 4: Upper box; 5: Lower box;

[0039] 11: liquid cooling plate; 111: current collector; 112: harmonica tube. DETAILED DESCRIPTION

[0040] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0041] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0042] For simplicity, only some numerical ranges are specifically disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and any upper limit can be combined with any other upper limit to form an unspecified range. In addition, each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.

[0043] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0045] Aluminum alloy materials have excellent properties that are superior to pure aluminum materials and are widely used in production and life. For example, in the field of batteries, liquid cooling plates are usually used between two battery cells for heat dissipation, and aluminum alloys are often used for such liquid cooling plates. However, the existing aluminum alloys, such as 3003 aluminum alloy, have a high solid solution strengthening effect due to the high mass percentage of manganese in the alloy of 1.0%-1.5%. The above content of manganese has a high solid solution strengthening effect, which makes the strength of the aluminum alloy too high, the extrusion processing performance is poor, and the elongation is small.

[0046] In the aluminum alloy of the present invention, the mass percentages of manganese, iron and silicon, as well as the mass ratio of Fe to Si are controlled. Within the range of Fe and Si addition, the solid solubility of Mn in the aluminum alloy matrix will be reduced. Fe can also promote the formation of crystal nuclei during the solidification process of the ingot, and play a role in grain refinement. By controlling the above range, on the one hand, the existence form of Mn in the aluminum alloy is adjusted, so that Mn has a suitable solid solution strengthening effect, the extrusion processing performance of the aluminum alloy is improved, the extrusion production efficiency and the die life are improved, the comprehensive processing cost is reduced, and the aluminum alloy has excellent strength. On the other hand, it can promote the second phase of the aluminum alloy to form α-Al with plasticity. 12 (Fe, Mn)3Si, reducing the brittle phase β-Al 85 (Mn, Fe) 14 The formation of Si, α-Al 12 (Fe, Mn)3Si is distributed in the aluminum alloy, which can promote recrystallization and refine the grains, thereby improving the elongation of the aluminum alloy.

[0047] The aluminum alloy disclosed in the embodiment of the present application is suitable for secondary batteries, and the secondary batteries disclosed in the embodiment of the present application can be used in electrical equipment using batteries as power sources or various energy storage systems using batteries as energy storage elements. Electrical equipment may include, but is not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0048] In a first aspect, the present application proposes an aluminum alloy, which comprises, in terms of mass percentage, 0.75%-0.9% Mn, 0.30%-0.36% Fe, 0.18%-0.23% Si, and the remainder being Al and unavoidable impurities; wherein, in the aluminum alloy, the mass ratio of the Fe to the Si is a, a≤2.

[0049] The present application at least includes the following beneficial effects: in the aluminum alloy of the present application, the mass percentages of manganese, iron and silicon, as well as the mass ratio of Fe to Si are controlled, so that Mn has a suitable solid solution strengthening effect, the extrusion processing performance of the aluminum alloy is improved, the extrusion production efficiency and the die life are improved, and the comprehensive processing cost is reduced, while the aluminum alloy has excellent strength; on the other hand, the second phase of the aluminum alloy can be promoted to form α-Al 12 (Fe, Mn)3Si, reduce the formation of brittle phase, α-Al 12 (Fe, Mn)3Si is distributed in the aluminum alloy, which can promote recrystallization and refine the grains, thereby improving the elongation of the aluminum alloy. Through the combined effect of the above two aspects, the extrusion processing performance and elongation of the aluminum alloy can be improved.

[0050] It is understood that the second phase is a general term for all other phases in the material that are different from the matrix phase. That is, in the embodiment of the present application, the matrix phase is the aluminum phase, and the second phase is other substances other than aluminum or a phase formed by other substances and aluminum.

[0051] In some embodiments of the present application, a=1.3-2, optionally, a=1.4-1.9, for example, based on the total mass of the aluminum alloy, a may be 1-2, 1.3-1.9, 1.4-1.8, 1.5-1.7, etc. Specifically, by controlling the mass ratio of Fe to Si within the above range, the existence form of Mn in the aluminum alloy can be adjusted, and the second phase of the aluminum alloy can be promoted to form α-Al 12(Fe, Mn)3Si can reduce the generation of brittle phase and improve the extrusion processing performance and elongation of aluminum alloy. In other embodiments of the present application, based on the total amount of aluminum alloy, a=1.3-2, for example, a=1.4-1.9.

[0052] In some embodiments of the present application, the aluminum alloy includes 0.30%-0.36% Fe by mass. For example, the aluminum alloy may include 0.30%-0.35% Fe, 0.31%-0.34% Fe, 0.32%-0.33% Fe, etc. Specifically, controlling the mass percentage of Fe within the above range can refine the grains and promote the formation of α-Al as the second phase of the aluminum alloy. 12 (Fe, Mn)3Si reduces the formation of brittle phase and can improve the extrusion processing performance and elongation of the aluminum alloy. In other embodiments of the present application, the aluminum alloy includes 0.30%-0.36% Fe in terms of mass percentage.

[0053] In some embodiments of the present application, the aluminum alloy includes 0.75%-0.9% Mn by mass percentage, for example, the aluminum alloy may include 0.75%-0.88% Mn, 0.75%-0.84% ​​Mn, 0.76%-0.83% Mn, 0.77%-0.82% Mn, 0.78%-0.81% Mn, 0.79%-0.80% Mn, etc. Specifically, by controlling the mass percentage of Mn within the above range, Mn can have a suitable solid solution strengthening effect in the aluminum alloy, improve the extrusion processing performance and elongation of the aluminum alloy, and the aluminum alloy has excellent strength. In other embodiments of the present application, the aluminum alloy includes 0.75%-0.85% Mn by mass percentage, for example, 0.75%-0.8% Mn.

[0054] In some embodiments of the present application, the aluminum alloy includes 0.18%-0.23% Si by mass percentage. For example, the aluminum alloy may include 0.18%-0.22% Si, 0.19%-0.21% Si, 0.20%-0.21% Si, etc. By controlling the mass percentage of Si within the above range, the grains can be refined and the second phase of the aluminum alloy can be promoted to form α-Al 12 (Fe, Mn)3Si reduces the formation of brittle phase and can improve the extrusion processing performance and elongation of the aluminum alloy. In other embodiments of the present application, the aluminum alloy includes 0.18%-0.21% Si in terms of mass percentage.

[0055] In some embodiments of the present application, the aluminum alloy further comprises, by mass percentage, at least one of (1) to (3):

[0056] (1) 0.05%-0.1% Cu. For example, the aluminum alloy may also include 0.05%-0.09% Cu, 0.06%-0.08% Cu, 0.07%-0.08% Cu, etc., in terms of mass percentage. The Cu content is controlled within the above range so that Cu has a suitable solid solution strengthening effect, improves the extrusion processing performance of the aluminum alloy, and at the same time makes the aluminum alloy have excellent strength.

[0057] (2) 0.001%-0.1% Zn. For example, the aluminum alloy may further include 0.001%-0.09% Zn, 0.01%-0.08% Zn, 0.02%-0.07% Zn, 0.03%-0.06% Zn, 0.04%-0.05% Zn, etc., by mass percentage. Controlling the Zn content within the above range can improve the extrusion processing performance of the aluminum alloy and make the aluminum alloy have excellent strength. In other embodiments of the present application, the aluminum alloy further includes 0.001%-0.03% Zn by mass percentage.

[0058] (3) 0.001%-0.05% Ti. For example, the aluminum alloy may also include 0.001%-0.05% Ti, 0.01%-0.04% Ti, 0.02%-0.03% Ti, etc., by mass percentage. When the content of Ti is controlled within the above range, Ti can form a TiAl2 phase with Al, which becomes a non-spontaneous core during crystallization, plays a role in refining the structure, and can improve the extrusion processing performance and elongation of the aluminum alloy, while making the aluminum alloy have excellent strength. In other embodiments of the present application, the aluminum alloy also includes 0.01%-0.03% Ti by mass percentage.

[0059] In some embodiments of the present application, the aluminum alloy further comprises Al. Al is the main constituent substance of the aluminum alloy and is the main component.

[0060] In some embodiments of the present application, the aluminum alloy also includes inevitable impurities, and the inevitable impurities include inevitable impurities in the raw materials and inevitable impurities introduced during the preparation process. For example, the inevitable impurities may include but are not limited to at least one of Ni, B, Zr or V.

[0061] The second aspect of the present application provides a method for preparing the aluminum alloy according to the first aspect, comprising:

[0062] S100: The aluminum alloy raw material is melted and cast to obtain a blank

[0063] It is understandable that the aluminum alloy raw material can be a single substance or an alloy, such as ferromanganese alloy. In this case, the ferromanganese alloy can also be used as an Fe source.

[0064] In some embodiments of the present application, in order to reduce the amount of inevitable impurities, in the examples of the present application, Al with a mass percentage greater than 99.7% is used.

[0065] In some embodiments of the present application, the smelting process includes: melting, refining, degassing, and deslagging.

[0066] In some embodiments of the present application, melting is to mix and heat the aluminum alloy raw materials to above the melting point to form liquid aluminum.

[0067] Refining is to remove impurities. In some embodiments of the present application, three refining steps are used to effectively remove impurities in the aluminum alloy, thereby achieving good extrusion processing performance and high elongation.

[0068] Specifically, the parameters of the three refining processes are shown in Table 1:

[0069] Table 1

[0070]

[0071] In Table 1, in the refining agent, based on the total weight of the refining agent, the mass fraction of each element is: K: 10-14 weight parts, Na: 22-27 weight parts, Cl: 33-40 weight parts, F: 11-15 weight parts; in the amount of refining agent, the amount of refining agent added per ton (t) of aluminum alloy is 1.5Kg-2Kg, for example, the total amount of refining agent added per ton of aluminum alloy can be 1.5Kg-1.9Kg, 1.6Kg-1.8Kg, 1.7Kg-1.8Kg, etc., 30% of the total mass of the refining agent is used for the first time, 50% of the total mass of the refining agent is used for the second time, and 20% of the total mass of the refining agent is used for the third time.

[0072] In some embodiments of the present application, the refining temperature is 680°C-760°C. For example, the refining temperature can be 680°C-750°C, 690°C-740°C, 700°C-730°C, 710°C-720°C, etc. By controlling the refining temperature within the above range, impurities in the aluminum alloy can be well removed, and defects such as pores, slag inclusions, and looseness of the aluminum alloy can be reduced, so that the extrusion processing performance and deformation resistance are good, and the elongation is high. In other embodiments of the present application, the refining temperature is 730°C-760°C.

[0073] In some embodiments of the present application, the refining pressure is 0.1Mpa-0.25Mpa, for example, the refining pressure can be 0.1Mpa-0.22Mpa, 0.13Mpa-0.2Mpa, 0.15Mpa-0.19Mpa, etc. By controlling the refining pressure within the above range, impurities in the aluminum alloy can be well removed, so that the extrusion processing performance is good and the elongation is high. In other embodiments of the present application, the refining pressure is 0.2Mpa-0.25Mpa.

[0074] In some embodiments of the present application, after refining, the aluminum alloy is allowed to stand for 20 min-30 min. For example, the aluminum alloy may be allowed to stand for 20 min-29 min, 21 min-28 min, 22 min-27 min, 23 min-26 min, 24 min-25 min, etc. This can effectively remove impurities in the aluminum alloy and also achieve a degassing effect.

[0075] In some embodiments of the present application, gas blowing is used for degassing. Specifically, a double-rotor degassing box can be used for degassing. The degassing medium is argon with a volume fraction of 99.99%. This can reduce defects such as pores, slag inclusions, and looseness in the aluminum alloy. At the same time, the stirring action of the rotor can make the alloy composition in the aluminum liquid more uniform, thereby improving the extrusion processing performance and elongation of the aluminum alloy.

[0076] The gas blowing method, also known as the floating method, is mainly to blow inert gas into the aluminum liquid to form many tiny bubbles. The initial pressure of the gas in the bubble is zero, and there is a pressure difference at the interface between the bubble and the aluminum liquid, so that the gas in the aluminum liquid is continuously absorbed into the bubble. This absorption process will not stop until the pressure of the gas in the bubble is equal to the pressure of the gas in the aluminum liquid. After the bubble floats to the surface of the liquid, the gas in the bubble escapes and enters the atmosphere.

[0077] The working principle of the double-rotor degassing box is that when the motor drives the rotor to rotate, inert gases such as argon are broken into very small bubbles. The presence of these small bubbles reduces the concentration of hydrogen in the aluminum liquid and the partial pressure on its surface, thereby reducing the concentration of hydrogen in the aluminum liquid, so that the hydrogen is carried out to the surface of the aluminum liquid by the argon gas and burned and consumed on the liquid surface.

[0078] In addition, when the small argon bubbles move from the bottom of the aluminum liquid to the surface of the aluminum liquid, on the one hand, the hydrogen dissolved in the aluminum liquid changes from a dissolved state to an adsorbed state when it hits the argon-aluminum liquid interface, and the gas atoms in the adsorption layer react to generate hydrogen molecules, which rise to the surface of the aluminum liquid and burn as the bubbles grow; on the other hand, when the small argon bubbles move from the bottom of the aluminum liquid to the surface, the suspended inclusion particles in the aluminum liquid are stirred, and the inclusions collide with each other, gather and grow. When the inclusions reach a certain size, they may collide with the floating bubbles, be captured, and then be brought to the liquid surface, achieving the effect of slag removal.

[0079] In some embodiments of the present application, the degassing pressure is 0.3MPa-0.6MPa. For example, the degassing pressure may be 0.3MPa-0.55MPa, 0.35MPa-0.5MPa, 0.4MPa-0.45MPa, etc. Within the above degassing pressure range, the generation of bubbles in the aluminum alloy can be reduced, and the extrusion processing performance and elongation of the aluminum alloy can be improved.

[0080] In some embodiments of the present application, the degassing flow rate is 3m 3 / h-6m 3 / h, for example, the degassing flow rate can be 3m3 / h-5.5m 3 / h, 3.5m 3 / h-5m 3 / h,4m 3 / h-4.5m 3 / h, etc., the degassing flow rate is the flow rate of the inert gas. Within the above-mentioned degassing flow rate range, the generation of bubbles in the aluminum alloy can be reduced, and the extrusion processing performance and elongation of the aluminum alloy can be improved.

[0081] In some embodiments of the present application, slag removal is to remove infusible impurities in aluminum liquid. While using a dual-rotor degassing box to pass argon gas to remove hydrogen, some inclusions are brought to the liquid surface with the floating bubbles, which has a certain slag removal effect. The slag is mainly removed online by filtering. The filtering method is a purification method that allows aluminum melt to pass through a filter made of neutral or active materials to separate solid inclusions suspended in the aluminum melt. At present, ceramic foam filter plates are mainly used, which are replaced once every furnace. In order to enhance the filtering effect, bipolar filtration is generally used.

[0082] In some embodiments of the present application, the casting molding process is the process of casting liquid aluminum into solid aluminum alloy. Specifically, the aluminum liquid is first filtered with a 40-60 mesh bipolar filter plate, and then cast into an aluminum alloy rod. The speed of the casting molding process is 105mm / min-125mm / min. For example, the speed of the casting molding process can be 105mm / min-120mm / min, 110mm / min-120mm / min, 110mm / min-115mm / min, etc. The flow rate of cooling water during the casting molding process is 3000L / min-4000L / min. For example, the flow rate of cooling water during the casting molding process can be 3000L / min-3900L / min, 3100L / min-3800L / min, 3200L / min-3700L / min, 3300L / min-3600L / min, 3400L / min-3500L / min, etc.

[0083] S200: homogenizing the blank and cooling it to obtain an aluminum alloy

[0084] Homogenization is a homogenization treatment, which can be carried out in a homogenization furnace. Homogenization can improve the crystal structure inside the aluminum alloy, eliminate casting stress, and reduce segregation.

[0085] In some embodiments of the present application, the temperature of the homogenization treatment is 600°C-610°C. For example, it can be 600°C-609°C, 601°C-608°C, 602°C-607°C, 603°C-606°C, 604°C-605°C, etc. Therefore, within the temperature range of the homogenization treatment, the extrusion processing performance and elongation of the aluminum alloy can be improved.

[0086] In some embodiments of the present application, the homogenization time is greater than or equal to 10 hours, for example, the homogenization time can be 10 hours to 100 hours, 20 hours to 90 hours, 30 hours to 80 hours, 40 hours to 70 hours, 50 hours to 60 hours, etc. Thus, within the time range of the above homogenization, the extrusion processing performance and elongation of the aluminum alloy can be improved. In other embodiments of the present application, the homogenization time is 10 hours to 11 hours.

[0087] In some embodiments of the present application, the cooling includes air cooling. Compared with other cooling methods such as liquid cooling, air cooling has a slow cooling speed, which can reduce the shrinkage deformation of the aluminum alloy during cooling, reduce the hardening degree of the aluminum alloy surface, increase the elongation, and improve the extrudability of the aluminum alloy.

[0088] In some embodiments of the present application, the cooling rate of the air cooling is 150°C / h-170°C / h. For example, the cooling rate of the air cooling can be 150°C / h-165°C / h, 155°C / h-160°C / h, 156°C / h-159°C / h, etc. Within the above cooling rate range, the shrinkage deformation of the aluminum alloy during cooling can be reduced, the surface hardening degree can be reduced, the elongation can be increased, and the extrudability of the aluminum alloy can be improved. In other embodiments of the present application, the cooling rate of the air cooling is 150°C / h-160°C / h.

[0089] A third aspect of the present application provides a liquid cooling plate, comprising the aluminum alloy described in the first aspect of the present application or the aluminum alloy prepared by the preparation method described in the second aspect.

[0090] See also Figure 1 The liquid cooling plate 11 of the embodiment of the present application includes a current collector 111 and a plurality of harmonica tubes 112 arranged side by side and interconnected. The current collector 111 and the harmonica tubes 112 are interconnected. The cooling liquid flows into the harmonica tubes 112 from one current collector 111, flows through the plurality of harmonica tubes 112, and then flows out from another current collector 111, thereby realizing heat exchange and playing the role of cooling and absorbing the heat of the battery cells.

[0091] In some embodiments of this application, please refer to Figure 2 The cross-sectional view of the harmonica tube 112 is similar to that of a harmonica, and has a large heat exchange area. The harmonica tube 112 includes the aluminum alloy described in the first aspect of the present application or the aluminum alloy prepared by the preparation method described in the second aspect, and has excellent extrusion processing performance, elongation, and excellent strength.

[0092] In some embodiments of the present application, the aluminum alloy of the present application can be processed into a harmonica tube by the following method: heating, extruding, online air-cooling quenching, stretching and straightening, and sawing the aluminum alloy to obtain a harmonica tube.

[0093] It should be noted that the processes of heating, extruding, online air-cooling quenching, stretching and straightening, and sawing the harmonica tube of the present application are all conventional operations in the art and will not be described in detail here.

[0094] Therefore, the liquid cooling plate 11 of the present application has excellent extrusion processing performance and deformation resistance, as well as elongation. When the liquid cooling plate 11 is arranged between two or more battery cells of the battery, it plays a role in cooling and absorbing the heat of the battery cells, and can adaptively expand and contract according to the expansion and contraction of the battery cells, thereby improving the life of the liquid cooling plate 11.

[0095] In some embodiments of the present application, the liquid cooling plate may include a multifunctional elastic sandwich liquid cooling plate, the multifunctional elastic sandwich liquid cooling plate includes a harmonica tube, the harmonica tube includes the aluminum alloy described in the first aspect of the present application or the aluminum alloy prepared by the preparation method described in the second aspect, the liquid cooling plate has excellent extrusion processing performance and high elongation, can adaptively expand and contract according to the expansion and contraction of the battery cell, and has excellent strength, thereby increasing the life of the liquid cooling plate.

[0096] The fourth aspect of the present application provides a battery, which includes the liquid cooling plate described in the third aspect of the present application. The above-mentioned liquid cooling plate is arranged between two or more battery cells of the battery, plays the role of cooling and absorbing the heat of the battery cells, and has excellent extrusion processing performance and high elongation. It can be adaptively expanded and contracted according to the expansion and contraction of the battery cells, thereby increasing the life of the liquid cooling plate.

[0097] A battery is a battery that can be used again by recharging the active materials after discharge.

[0098] It is understandable that the battery proposed in this application can be a lithium-ion battery or a sodium-ion battery.

[0099] Generally, a battery includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte. During the charge and discharge process of the battery, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet to play a role of isolation. The electrolyte plays a role of conducting ions between the positive electrode sheet and the negative electrode sheet.

[0100] [Positive electrode]

[0101] In some embodiments of the present application, the positive electrode plate includes a positive current collector, and the positive current collector can be a metal foil, a foam metal or a composite current collector. For example, as a metal foil, aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium with a silver surface treatment can be used. The composite current collector may include a polymer material base and a metal layer. The foam metal may be a nickel foam, a copper foam, an aluminum foam, a foam alloy, or a carbon foam. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0102] In some embodiments of the present application, the positive electrode plate may further include a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode active material. The specific type of the positive electrode active material is not limited, and active materials known in the art that can be used for battery positive electrodes can be used. Those skilled in the art can select according to actual needs.

[0103] For example, when the battery is a lithium-ion battery, as an example, the positive electrode active material may include, but is not limited to, at least one of lithium transition metal oxides, lithium-containing phosphates of olivine structure and their respective modified compounds. Examples of lithium transition metal oxides may include, but are not limited to, at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and their modified compounds. Examples of lithium-containing phosphates of olivine structure may include, but are not limited to, at least one of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, a composite material of lithium iron manganese phosphate and carbon and their modified compounds. These materials can all be obtained commercially.

[0104] For example, when the battery is a sodium ion battery, as an example, the positive electrode active material may include but is not limited to at least one of a layered transition metal oxide, a polyanion compound, and a Prussian blue analog.

[0105] Examples of the layered transition metal oxides include:

[0106] Na 1-x Cu h Fe k Mn l M 1 m O 2-y , where M 1is at least one of Li, Be, B, Mg, Al, K, Ca, Ti, Co, Ni, Zn, Ga, Sr, Y, Nb, Mo, In, Sn and Ba, 0 <x≤0.33,0<h≤0.24,0≤k≤0.32,0<l≤0.68,0≤m<0.1,h+k+l+m=1,0≤y<0.2;

[0107] Na 0.67 Mn 0.7 Ni z M 2 0.3-z O2, where M 2 is at least one of Li, Mg, Al, Ca, Ti, Fe, Cu, Zn and Ba, 0 <z≤0.1;

[0108] Na a Li b Ni c Mn d Fe e O2, of which 0.67 <a≤1,0<b<0.2,0<c<0.3,0.67<d+e<0.8,b+c+d+e=1。

[0109] Examples of the polyanionic compound include:

[0110] A 1 f M 3 g (PO4) i O j X 1 3-j , where A 1 is at least one of H, Li, Na, K and NH4, M 3 is at least one of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X 1 is at least one of F, Cl and Br, 0 <f≤4,0<g≤2,1≤i≤3,0≤j≤2;

[0111] Na n M 4 PO4X 2 , where M 4 is at least one of Mn, Fe, Co, Ni, Cu and Zn, X 2 is at least one of F, Cl and Br, 0 <n≤2;

[0112] Na p M 5 q (SO4)3, where M 5is at least one of Mn, Fe, Co, Ni, Cu, and Zn, 0 < p ≤ 2, 0 < q ≤ 2;

[0113] Na s Mn t Fe 3-t (PO4)2(P2O7), where 0 < s ≤ 4, 0 ≤ t ≤ 3, for example, t is 0, 1, 1.5, 2, or 3.

[0114] As an example of the above-mentioned Prussian blue analogues, for example, the following can be listed:

[0115] A u M 6 v [M 7 (CN)6] w ·xH2O, where A is H + , NH4 + , at least one of alkali metal cations and alkaline earth metal cations, M 6 and M 7 are each independently at least one of transition metal cations, 0 < u ≤ 2, 0 < v ≤ 1, 0 < w ≤ 1, 0 < x < 6. For example, A is H + , Li + , Na + , K + , NH4 + , Rb + , Cs + , Fr + , Be 2+ , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Ra 2+ , at least one of M 6 and M 7 are each independently cations of at least one transition metal element among Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, and W.

[0116] The modified compounds of the above materials can be doping modification and / or surface coating modification of the materials.

[0117] The positive electrode active material layer usually also optionally includes a binder, a conductive agent, and other optional additives.

[0118] As an example, the conductive agent can include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, SuperP (SP), graphene, and carbon nanofibers.

[0119] As an example, the adhesive may include at least one of styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA) and polyvinyl butyral (PVB).

[0120] [Negative electrode]

[0121] In some embodiments of the present application, the negative electrode plate includes a negative electrode current collector, and the negative electrode current collector can be a metal foil, a foam metal or a composite current collector. For example, as a metal foil, aluminum or stainless steel treated with silver surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. can be used. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, or foam carbon, etc. The composite current collector may include a polymer material base layer and a metal layer, and the composite current collector may be formed by placing a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0122] In some embodiments of the present application, the negative electrode plate may further include a negative electrode active material layer, and the negative electrode active material layer includes a negative electrode active material. The specific type of the negative electrode active material is not limited, and active materials known in the art that can be used for battery negative electrodes can be used. Those skilled in the art can select according to actual needs.

[0123] As an example, the negative electrode active material may include but is not limited to at least one of artificial graphite, natural graphite, hard carbon, soft carbon, silicon-based materials and tin-based materials. The silicon-based material may include at least one of elemental silicon, silicon oxide (e.g., silicon monoxide), silicon-carbon composite, silicon-nitrogen composite, and silicon alloy. The tin-based material may include at least one of elemental tin, tin oxide, and tin alloy. These materials can all be obtained commercially.

[0124] In some embodiments of the present application, in order to further improve the energy density of the battery, the negative electrode active material may include a silicon-based material.

[0125] The negative electrode active material layer may also optionally include a binder, a conductive agent and other optional auxiliary agents.

[0126] As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0127] As an example, the adhesive may include at least one of styrene butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

[0128] As examples, other optional additives may include thickeners and dispersants (eg, sodium carboxymethyl cellulose CMC-Na), and PTC thermistor materials.

[0129] [Isolation film]

[0130] In some embodiments of the present application, as the above-mentioned isolation membrane, the present application has no particular restrictions, and any known porous structure isolation membrane with electrochemical stability and mechanical stability can be selected according to actual needs. For example, it can be a single-layer or multi-layer film containing at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0131] [Electrolyte]

[0132] In some embodiments of the present application, the battery may further include an electrolyte, which may include an electrolyte salt and a solvent.

[0133] As an example, when the battery is a lithium ion battery, the electrolyte lithium salt may include at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobis(oxalatophosphate) (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).

[0134] As an example, when the battery is a sodium ion battery, the electrolyte sodium salt includes at least one of sodium hexafluorophosphate, sodium difluorooxalatoborate, sodium tetrafluoroborate, sodium bisoxalatoborate, sodium perchlorate, sodium hexafluoroarsenate, sodium bis(fluorosulfonyl)imide, sodium trifluoromethylsulfonate and sodium bis(trifluoromethylsulfonyl)imide.

[0135] As an example, the solvent may include at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS) and diethyl sulfone (ESE).

[0136] In some embodiments of the present application, the electrolyte further includes additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high temperature performance, and additives that improve battery low temperature performance.

[0137] The embodiment of the present application has no particular limitation on the shape of the battery, i.e., the battery cell, which may be cylindrical, square, or any other shape. Figure 3 A square-structured battery 1 is shown as an example.

[0138] In some embodiments, the battery may include an outer packaging for packaging the positive electrode sheet, the negative electrode sheet, and the electrolyte.

[0139] In some embodiments, the outer package may include a shell and a cover plate. The shell may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell has an opening connected to the receiving cavity, and the cover plate can be covered on the opening to close the receiving cavity.

[0140] The positive electrode sheet, the negative electrode sheet and the separator can be wound or laminated to form an electrode assembly. The electrode assembly is packaged in the receiving cavity. The number of electrode assemblies contained in the battery can include one or more, which can be adjusted according to demand.

[0141] In some embodiments, the outer packaging of the battery may include a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell.

[0142] The outer packaging of the battery may also include a soft package, such as a bag-type soft package. The material of the soft package may be plastic, such as at least one of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0143] In some embodiments, the batteries may be assembled into a battery module. The battery module may contain multiple batteries, and the specific number may be adjusted according to the application and capacity of the battery module.

[0144] Figure 4 2 is an example of a battery module 2. Figure 4 In the battery module 2, the multiple batteries 1 may be arranged in sequence along the length direction of the battery module 2. Of course, they may also be arranged in any other manner. Further, the multiple batteries 1 may be fixed by fasteners.

[0145] The battery module 2 may also include a housing having a storage space, in which a plurality of batteries 1 are stored. In some embodiments, the battery modules may be assembled into a battery pack, and the number of battery modules contained in the battery pack may be adjusted according to the application and capacity of the battery pack.

[0146] Figure 5 and 6 The battery pack 3 is used as an example. Figure 5 and 6 The battery pack 3 may include a battery box and a plurality of battery modules 2 disposed in the battery box. The battery box includes an upper box body 4 and a lower box body 5. The upper box body 4 can cover the lower box body 5 and form a closed space for accommodating the battery modules 2. The plurality of battery modules 2 can be arranged in the battery box in any manner.

[0147] The sixth aspect of the present application provides an electrical device, which includes the battery described in the fifth aspect. Specifically, the battery can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (such as mobile phones, laptops), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks), electric trains, ships and satellites, and energy storage systems.

[0148] Figure 7 The electrical equipment is used as an example, and the electrical equipment includes a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

[0149] As another example, the electric device may include a mobile phone, a tablet computer, and a notebook computer. The electric device is usually required to be thin and light, and a battery may be used as a power source.

[0150] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to the embodiments and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its applications. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0151] Example 1

[0152] Aluminum alloy preparation

[0153] Aluminum ingots (purity 99.7%), aluminum-silicon master alloy AlSi50, aluminum-manganese master alloy AlMn20, aluminum-iron master alloy AlFe10, and AlCu50 master alloy are prepared according to the mass percentage of aluminum alloy in Table 2 to obtain aluminum alloy raw materials, and the aluminum alloy raw materials are smelted, the smelting treatment includes melting, refining, degassing, and slag removal, and then cast and molded to obtain a blank, the blank is homogenized, and air-cooled to obtain an aluminum alloy rod with a diameter of 127 mm and a length of 300 mm. For specific preparation parameters, see Table 2.

[0154] During melting, the aluminum alloy raw material is put into a melting furnace and heated at 780° C. for 4 hours to melt into a liquid state.

[0155] During refining, three refinings were performed in a refining tank. The temperature of the three refinings was 750° C., the pressure of the three refinings was 0.22 MPa, the first refining time was 15 min, the second refining time was 20 min, and the third refining time was 15 min. The refining agents for the three refinings were a mixture of KCl, NaCl and NaF (based on the total weight of the refining agent, the mass fraction of each element was: K: 12 weight parts, Na: 25 weight parts, Cl: 35 weight parts, F: 13 weight parts, and the total amount of refining agent was 2 Kg / t (aluminum alloy)). The amount of refining agent for the first refining agent was 30% of the total amount of refining agent, the amount of refining agent for the second refining agent was 50% of the total amount of refining agent, and the amount of refining agent for the third refining agent was 20% of the total amount of refining agent. After the three refinings, the mixture was allowed to stand for 25 min.

[0156] A double-rotor degassing box is used for degassing. The degassing pressure is 0.45MPa and the flow rate of inert gas is 4.5m 3 / h, and the degassing medium is argon with a volume fraction of 99.99%.

[0157] When removing slag, the aluminum liquid is passed through a 50-mesh bipolar ceramic foam filter plate.

[0158] Preparation of harmonica pipe

[0159] The harmonica tube is obtained by heating, extruding, online air-cooling quenching, stretching and straightening, and sawing the aluminum alloy.

[0160] The aluminum alloys of Examples 2-42 and Comparative Examples 1-4 are the same as those of Example 1 except for the different parameters (see Table 2). In Examples 34-36, three refinings are also performed, and the refining temperature is the same each time. As shown in Table 2, if the aluminum alloy contains at least one of Cu, Zn or Ti, at least one of AlCu50 master alloy, zinc-aluminum alloy or AlTiCB alloy is added accordingly.

[0161] The mass percentages and preparation parameters of the aluminum alloys of Examples 1-42 and Comparative Examples 1-4 of the present application are shown in Table 2.

[0162] Table 2

[0163]

[0164]

[0165]

[0166] Performance Test:

[0167] 1. Extrusion performance test: The aluminum alloys of Examples 1-42 and Comparative Examples 1-4 were placed in a 1000T extruder for extrusion, and the maximum extrudable speed was read during the extrusion process.

[0168] 2. Elongation determination: The aluminum alloys of Examples 1-42 and Comparative Examples 1-4 were subjected to the tensile test of metallic materials in accordance with Part 1 of GB / T 228.1, and the elongation after fracture (A) was calculated according to formula (1):

[0169] A=(L u -L o ) / L o ×100 (1)

[0170] Among them, L u Indicates the gauge length after breaking, mm, L o Indicates the original gauge length, mm. The elongation after fracture (L u -L o ), and accurate to ±0.25mm.

[0171] 3. Strength measurement: The aluminum alloys of Examples 1-42 and Comparative Examples 1-4 were subjected to the tensile strength and yield strength test from the stress-elongation curve according to GB / T 228.1, Metallic Materials Tensile Test Part 1.

[0172] The test results are shown in Table 3.

[0173] Table 3

[0174]

[0175]

[0176] It can be seen from Table 3 that the aluminum alloys of Examples 1-42 of the present application control the mass percentages of manganese, iron and silicon, and the mass ratio of Fe to Si, improve the extrusion processing performance of the aluminum alloy, improve the extrusion production efficiency and die life, and have excellent elongation; Comparative Examples 1-4 do not simultaneously meet the mass percentage of manganese and the mass ratio of Fe to Si, and their extrusion processing performance and elongation are significantly lower than those of the embodiments.

[0177] It can be seen from Table 3 that the aluminum alloys of Examples 1-42 of the present application have excellent tensile strength and yield strength.

[0178] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An aluminum alloy, characterized in that: Measured in percentage by mass, the aluminum alloy includes 0.75%-0.9% Mn, 0.30%-0.36% Fe, 0.18%-0.23% Si, and the remainder is Al and unavoidable impurities; wherein, in the aluminum alloy, the mass ratio of the Fe to the Si is a, a≤2.

2. The aluminum alloy according to claim 1, characterized in that a=1.3-2, optionally, a=1.4-1.

9.

3. The aluminum alloy according to claim 1 or 2, characterized in that: In terms of mass percentage, the aluminum alloy includes 0.75%-0.85% of Mn, 0.30%-0.34% of Fe, 0.18%-0.21% of Si, and the balance is Al and unavoidable impurities; Optionally, the aluminum alloy includes, by mass percentage, 0.75%-0.8% Mn, 0.30%-0.34% Fe, 0.18%-0.21% Si, and the balance is Al and inevitable impurities.

4. The aluminum alloy according to any one of claims 1 to 3, characterized in that The aluminum alloy further comprises, by mass percentage, at least one of (1) to (3): (1) 0.05%-0.1% Cu; (2) 0.001%-0.1% Zn, optionally 0.001%-0.03% Zn; (3) 0.001%-0.05% Ti, optionally 0.01%-0.03% Ti.

5. A method for preparing the aluminum alloy according to any one of claims 1 to 4, characterized in that: include: The aluminum alloy raw material is smelted and cast to obtain a blank; The preform is homogenized and cooled to obtain an aluminum alloy.

6. The preparation method according to claim 5, characterized in that: The temperature of the homogenization treatment is 600° C.-610° C., and the time of the homogenization treatment is greater than or equal to 10 hours, and can be optionally 10 hours-11 hours.

7. The preparation method according to claim 5 or 6, characterized in that: The smelting process includes: melting, refining, degassing and deslagging; The refining temperature is 680°C-760°C, and can be optionally 730°C-760°C; The refining pressure is 0.1Mpa-0.25Mpa, and can be optionally 0.2Mpa-0.25Mpa.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The cooling process includes air cooling.

9. The preparation method according to claim 8, characterized in that: The air cooling rate is 150°C / h-170°C / h, and can be optionally 150°C / h-160°C / h.

10. A liquid cooling plate, characterized in that: The material of the liquid cooling plate includes the aluminum alloy described in any one of claims 1 to 4 or the aluminum alloy prepared by the preparation method described in any one of claims 5 to 9.

11. A battery, characterized in that: Comprising the liquid cooling plate according to claim 10.

12. An electrical device, characterized in that: Comprising the battery of claim 11.

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