CN-121976095-A - Al-Mn aluminum alloy strip for battery cover plate with balanced performance and preparation method thereof

Abstract

The invention belongs to the technical field of aluminum-based materials, and particularly relates to an Al-Mn aluminum alloy strip for a battery cover plate with balanced performance and a preparation method thereof. The aluminum alloy strip comprises ：Si0.10～0.20%,Fe0.30～0.50%,Cu0.05～0.10%,Mn1.20～1.60%,Sc0.05～0.12%,Zr0.04～0.08%,Mg≤0.010%,Zn≤0.010%,Ti0.02～0.03%, of components and the balance of Al. The aluminum alloy strip prepared by the method meets the omnibearing requirements of the new energy battery cover plate on high strength, high reliability and high consistency, and has remarkable technical advantages.

Inventors

• LI JIGANG
• LU XIHUI
• YANG QIURONG
• FAN XINGRUI
• QIN HONGBO
• DING RONGHUI
• SHEN MEIZHEN
• SU LIPING
• JIANG SHIZHOU
• WEI YUEPING
• LAI DAFENG
• DENG BANGJUN

Assignees

• 广西国潮铝业有限公司

Dates

Publication Date

20260505

Application Date

20260403

Claims (7)

1. 1. The preparation method of the Al-Mn aluminum alloy strip for the battery cover plate with balanced performance is characterized by comprising the following steps of: S1, smelting and casting, namely blending ：Si0.10～0.20%,Fe0.30～0.50%,Cu0.05～0.10%,Mn1.20～1.60%,Sc0.05～0.12%,Zr0.04～0.08%,Mg≤0.010%,Zn≤0.010%,Ti0.02～0.03%, the components and the balance of Al according to the mass fraction, smelting, refining, degassing and deslagging the blended raw materials, and then semi-continuously casting the raw materials into aluminum alloy slab ingots; S2, homogenizing, namely, after sawing and milling the surface of the slab ingot, heating the slab ingot to 520-540 ℃ in a protective atmosphere and preserving heat for 8-12 hours; S3, hot rolling, namely heating the slab ingot to 470-500 ℃ after homogenization treatment, preserving heat for 2-3 hours, discharging from a furnace, carrying out hot rolling, wherein the final rolling temperature of the hot rolling is 290-320 ℃, and the thickness of the hot rolling off-line is 2.2-2.6 mm; s4, carrying out solution treatment on the hot rolled strip in an air cushion type annealing furnace, wherein the treatment temperature is 525-535 ℃, the heat preservation time is 15-30 minutes, and the strip is forced to be cooled after being discharged from the furnace; s5, cold rolling, namely rolling the strip subjected to solution treatment on a cold rolling mill, wherein the cold working rate is 10% -18%; s6, cleaning, namely cleaning the cold-rolled strip in a recoiling machine to remove surface rolling oil and dirt; S7, coiling and low-temperature stabilization heat treatment, namely coiling the cleaned and dried strip, and then performing low-temperature stabilization heat treatment in a box annealing furnace, wherein the treatment temperature is 90-110 ℃, and the heat preservation time is 1-3 hours; s8, slitting, namely uncoiling the strip coil subjected to the low-temperature stabilization heat treatment, and slitting the strip coil into finished product widths required by customers on a slitting machine to prepare the Al-Mn aluminum alloy strip for the battery cover plate with balanced performance.
2. 2. The method according to claim 1, wherein in the step S2, the protective atmosphere is nitrogen.
3. 3. The method according to claim 1, wherein in the step S3, the total working ratio of the hot rolling is not less than 90%, and the single-pass working ratio of the last three passes is not more than 15%.
4. 4. The method according to claim 2, wherein in the step S4, the cooling rate after the solution treatment is 40 to 60 ℃.
5. 5. The method according to claim 1, wherein in the step S5, the roughness of the cold rolled work rolls is 0.20-0.30 μm and the rolling speed is 200-300 m/min.
6. 6. The preparation method according to claim 1, wherein in the step S7, nitrogen is introduced into the furnace as a protective atmosphere during the low-temperature stabilization heat treatment, and the micro positive pressure in the furnace is maintained at 50-200 pa.
7. 7. An al—mn aluminum alloy strip for battery cover plates with balanced properties, characterized by being produced by the production method according to any one of claims 1 to 6.

Description

Al-Mn aluminum alloy strip for battery cover plate with balanced performance and preparation method thereof Technical Field The invention belongs to the technical field of aluminum-based materials, and particularly relates to an Al-Mn aluminum alloy strip for a battery cover plate with balanced performance and a preparation method thereof. Background Along with the acceleration and promotion of global energy transformation, the new energy automobile industry is vigorously developed, and the performance and the reliability of a power battery serving as a core component of the power battery are directly related to the safety and the endurance mileage of the whole automobile. The power battery cover plate is used as a key structural part and a sealing part of a battery pack, not only has excellent formability to adapt to complex stamping processing, but also requires materials to have proper strength, stable surface characteristics, excellent welding performance and long-term reliable corrosion resistance. Currently, 3003-series (al—mn-series) aluminum alloys have become the most widely used material choice for power battery cover plates due to their good combination of properties, including excellent forming properties, satisfactory corrosion resistance, and high heat conductivity. However, with the improvement of battery energy density, the refinement of manufacturing process and the increasingly strict requirements on full life cycle traceability, the conventional 3003 aluminum alloy gradually exposes a plurality of key technical bottlenecks in practical scale application, and is difficult to completely meet the severe requirements of the high-end power battery cover plate: first, weld safety and seal reliability are challenging. The power battery shell and the cover plate are finally subjected to airtight packaging through laser welding and other processes. Because of the source of raw ores and the complexity of the smelting process, trace elements such as magnesium (Mg), zinc (Zn) and the like are inevitably brought into the conventional 3003 alloy. These low boiling point elements are extremely volatile in a high temperature molten pool generated by laser welding, so that air holes and splashes are formed in the welding process, and the phenomenon of 'welding spot explosion' is caused when serious. The appearance and compactness of the welding seam are obviously affected, the long-term sealing safety of the whole battery is fundamentally threatened, and the risks of electrolyte leakage and even thermal runaway can be possibly caused. Therefore, how to suppress the content of such harmful impurities from the ingredient design source is a key to improve the safety level of the battery. Secondly, there is a conflict between surface quality and the full-flow traceability requirement. In view of the requirements of automobile safety regulations and quality control, modern power batteries require that each single unit has traceability of the whole process flow, and information binding is usually realized on the surface of a cover plate through laser engraving of two-dimensional codes. Under the traditional production process, the surface of the aluminum alloy strip is easy to remain with annealing oil marks or generate interlayer dislocation and sticking injury in coiling and transportation. These microscopic surface defects can interfere with the definition and consistency of laser codes, resulting in a decrease in the identification rate of two-dimensional codes, directly resulting in an increase in the rejection rate of products, and affecting the production efficiency and cost control. Furthermore, the balance control and process stability of the material performance are needed to be optimized. The cover plate material needs to achieve precise balance among strength, plasticity and hardness, enough strength ensures structural rigidity of the cover plate, good plasticity (elongation) ensures smooth progress of complex stamping forming, and stable and moderate surface hardness is important for inhibiting scratches in a production process and providing a uniform substrate for subsequent laser coding. In the traditional hot rolling process, the final rolling temperature has obvious influence on the final structure state, namely, the temperature is too low, a large amount of processed fiber tissues are reserved in the material, the performance is uneven, and the temperature is too high (exceeds the recrystallization temperature), so that the tissues tend to soften, and the formation is facilitated, but the strength may be insufficient. The sensitivity to the process window causes performance fluctuation, and multiple intermediate anneals are often required to be introduced for adjusting the performance, so that the process flow is complicated, and the cost is increased. In summary, a novel aluminum alloy material is developed, which aims to solve the problems of potential safety hazards of welding, contradictio