고분자 블렌딩 및 연신조건이 리튬 이온전지용 습식 Separator 의 물성에 미치는 영향

문성인; 손영수; 김순식; 김진열; Sungin Moon; Yongsoo Son; Soonsik Kim; Jinyeol Kim

Polymer(Korea), Vol.26, No.1, 45-52, January, 2002

The Effect of Polymer Blending and Extension Conditions on the Properties of Separator Prepared by Wet Process for Li-ion Secondary Battery

문성인, 손영수, 김순식, 김진열^†

(주) 새한 기술연구소

Sungin Moon, Yongsoo Son, Soonsik Kim, and Jinyeol Kim^†

R & D Center, Saehan Industries Ltd, Suwon 440-600, Korea

E-mail:

초록

고밀도 폴리에틸렌(HDPE)과 초고분자량 폴리에틸렌(UHMWPE)을 블렌딩한 고분자 구조를 갖는 리튬이온 2차 전지용 습식 separator를 제조하였으며, 그들의 고분자 블렌딩 및 연신 조건이 제반물성에 미치는 영향에 관해서 고찰하였다. Separator의 기계적 강도는 UHMWPE의 분자량 및 함량이 증가함에 따라 크게 향상되었으며, UHMWPE의 함량이 6 wt%이며 5배 연신 필름에서 약 1000 kg/cm2의 기계적 강도를 보이며 제막성 또한 우수한 것으로 나타났다. Separator의 기공구조는 0.1~0.12 mm로 균일성을 보였으며, shut-down특성은 130 ℃ 부근에서 급격히 상승하여 160 ℃에서 용융되는 것으로 나타났고 따라서 리튬이온 2차전지에 적용 가능한 것으로 평가되었다.

The separator made from the blends of high density polyethylene (HDPE) and ultrahigh molecular weight polyethylene (UHMWPE) was prepared by wet processing to use as Li-ion secondary battery. We investigated effects of the blending of the polymers and the film extension on the mechanical properties of the separator. The mechanical strength of separator increased with increasing molecular weights and contents of UHMWPE, for instance about 1000 kg/cm2 with the five times extended film of 6 wt% UHMWPE. The pores of the separator were very uniform with the size of 0.1~0.12 mm. The shut-down characteristic quickly increased at around 130 ℃ and the fusion temperature was 160 ℃, so it could be applied to the lithium ion secondary battery.

Keywords:separator;Li-ion secondary battery;wet process

[References]

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Kim SS, Lloyd DR, J. Membr. Sci., 64, 13 (1991)
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Kasei A, Japan Patent, 8-64194 (1996)
Celanese H, U.S. Patent, 3,558,764
Denko N, U.S. Patent, 5,385,777
Lloyd DR, Kim SS, Kinzer KE, J. Membr. Sci., 64, 1 (1991)

[1] Xu M, 5th Pacific Polymer Conference, p. 10, 1997 (1997)

[2] Callahan R, Yu WC, Geiger M, Dwiggins C, Fisher H, Hoffman D, Abraham KM, Jillson MH, Nguyen TH, The 11th Int. Seminar on Primary and a Secondary Battery Tech and Appl., 1995 (1995)

[3] Tonen, Japan Patent, 8-12799 (1996)

[4] Bierenbaum HS, Isaacson RB, Druin ML, Plovan SG, Ind. Eng. Chem. Prod. Res. Dev., 13, 2 (1974)

[5] "Marketing Report of Li ion Battery," Nomura Reserach, March. 1997 (1997)

[6] Kim SS, Lloyd DR, J. Membr. Sci., 64, 13 (1991)

[7] Japanese Industrial News, 91 (1996)

[8] Tonen, Japan Patent, 63-273651

[9] Kasei A, Japan Patent, 8-64194 (1996)

[10] Celanese H, U.S. Patent, 3,558,764

[11] Denko N, U.S. Patent, 5,385,777

[12] Lloyd DR, Kim SS, Kinzer KE, J. Membr. Sci., 64, 1 (1991)