(1. 中國(guó)科學(xué)院力學(xué)研究所 先進(jìn)制造工藝力學(xué)重點(diǎn)實(shí)驗(yàn)室，北京 100190；
2. 山東聚信新能源科技有限公司，濱州 256200)
摘 要: 針對(duì)鋁箔集流體表面改性的要求，基于激光毛化技術(shù)軋制13 μm厚的1070鋁箔，研究表面毛化參數(shù)對(duì)鋁箔的力學(xué)性能和作為鋰離子電池正極集流體的加工性能的影響。表面毛化鋁箔的表面粗糙度Ra達(dá)到0.7~1.0 μm，為常規(guī)鋁箔的7.4~9.7倍，表面毛化坑誘導(dǎo)的應(yīng)力集中效應(yīng)使鋁箔的屈服強(qiáng)度和拉伸強(qiáng)度降低4%~10%，而表面毛化坑造成的鋁箔局部減薄和板型變化對(duì)伸長(zhǎng)率的影響更加顯著。采用相互分離的低密度毛化坑(分布參數(shù)140 μm×140 μm)時(shí)，表面毛化鋁箔的伸長(zhǎng)率僅降低約10%。而采用相切的高密度毛化坑(分布參數(shù)70 μm×70 μm)時(shí)，表面毛化鋁箔的伸長(zhǎng)率降低約50%。兩種表面毛化鋁箔制成的正極極片的LiCoO2涂層剝離強(qiáng)度均達(dá)到常規(guī)鋁箔極片的1.6倍，分散性?xún)H為常規(guī)鋁箔極片的16%~32%。毛化鋁箔的表面粗糙度Ra值在0.7 μm附近存在臨界點(diǎn)，繼續(xù)增大不能有效地提高涂層對(duì)鋁箔集流體的剝離強(qiáng)度，反而損失其力學(xué)性能。模擬鋰離子電池正極極片的輥壓和烘干工藝后，表面毛化鋁箔(分布參數(shù)140 μm×140 μm)的力學(xué)性能與常規(guī)鋁箔的相當(dāng)，但鋁箔表面毛化坑誘導(dǎo)的應(yīng)力集中現(xiàn)象能夠促進(jìn)鋁箔均勻變形，抵抗局部損傷能力強(qiáng)，提高電池卷芯對(duì)整形壓力的寬容度，有助于避免最內(nèi)層極片的局部斷裂現(xiàn)象。
關(guān)鍵字: 激光表面毛化；鋁箔集流體；力學(xué)性能；剝離強(qiáng)度
（1. Key Lab of Mechanics in Advanced Manufacturing, Institute of Mechanics, Chinese Academy of Science, Beijing 100190, China;
2. Shan Dong JU XIN Amperex Technology Ltd, Binzhou 256200, China）
Abstract:According to the requirement of surface modification of aluminum foil as current collector, a kind of 1070 aluminum foil with the thickness of 13 μm was rolled by laser texturing technology. The effects of surface texturing parameters on the mechanical properties of aluminum foil and its processing properties as a positive electrode current collector for lithium-ion battery were studied. The Ra value of surface textured aluminum foil is about 0.7-1.0 μm, which is 7.4-9.7 times than that of normal aluminum foil. It is found that the stress concentration effect induced by the surface textured craters reduced the yield strength and tensile strength of aluminum foil from 3.4%-11.5%, and the local thinning of aluminum foil and the change of plate shape caused by the surface texturing craters have more significant effect on the elongation of aluminum foil. With the separated low density surface textured craters (distribution parameter 140 μm×140 μm), the elongation of the aluminum foil is only reduced about 10%. However, with the tangential high density surface textured crater (distribution parameter 70 μm×70 μm), the elongation of the aluminum foil is reduced by about 50%. The adhesion strength of LiCoO2 coating of positive electrode slice to the surface textured aluminum foil is 1.6 times than that to the normal aluminum foil, and the mean squared error of the former is only 16%-32% than the latter. It is a critical point of surface roughness about Ra 0.7 μm for the surface textured aluminum foil that higher Ra than it can not effectively improve the adhesion strength of the positive electrode coating to aluminum foil as current collector, but loses the mechanical properties of aluminum foil. After simulating the rolling process and drying process of the positive electrode slice of lithium-ion battery, the mechanical properties of the surface textured aluminum foil (distribution parameter 140 μm×140 μm) are similar with those of the normal aluminum foil. However, the uniform deformation of aluminum foil is promoted by the stress concentration phenomenon induced by textured craters on the surface of aluminum foil to have strong resistance to local damage of aluminum foil and higher tolerance to the shaping pressure of the battery coil. It is helpful to avoid the local fracture phenomenon of the innermost positive electrode splice.
Key words: laser surface texturing; aluminum foil current collector; mechanical property; adhesion strength
