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Manufacturing Integral Safety Vents in Prismatic Lithium-ion Batteries

직사각형 리튬 이온 전지의 일체형 안전장치 제조 공정에 관한 연구

  • Received : 2015.05.04
  • Accepted : 2015.06.24
  • Published : 2015.08.01

Abstract

A safety vent is crucial to protect its user from unpredictable explosions caused by increasing internal pressure of the lithium-ion batteries. In order to prevent the explosion of the battery, a safety vent rupture is required when the internal pressure reaches a critical value. In conventional manufacturing, the cap plate and the safety vent are fabricated separately and subsequently welded to each other. In the current study, a manufacturing process including a backward extrusion and coining process is suggested to produce an integral safety vent which also has the benefit of increasing production efficiency. FE simulations were conducted to predict the rupture pressure and to design the safety vent using a ductile fracture criterion and the element deletion method. The critical value, C, in the ductile fracture criterion was obtained from uniaxial tensile tests with an annealed sheet of 1050-H14 aluminum alloy. Rupture tests were preformed to measure the rupture pressure of the safety vent. The results met the required rupture pressure within 8.5±0.5 kgf/cm2. The simulation results were compared with experimental results, which showed that the predicted rupture pressures are in good agreement with experimentally measured ones with a maximum error of only 3.9%.

Keywords

Lithium-ion Battery;Integral Safety Vent,;Backward Extrusion;Coining;Ductile Fracture;Rupture Pressure

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Acknowledgement

Grant : 첨단 기계부품소재 인력양성사업단