• Journal of the Korean Society for Precision Engineering
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• v.33 no.10
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• pp.813-820
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• 2016

Hybrid Electric Vehicles (HEVs) are developed to be operated with two kinds of power source (Diesel Engine and Electric Motor with Rechargeable High Voltage Battery Pack). HEVs for military vehicle require high reliability to provide stable powers under serious environment such as vibration and shock. To ensure normal operation of battery pack under serious environment such as vibration and shock, the high voltage battery pack needs to have appropriate dynamic characteristics. This paper presents a design procedure for high voltage battery pack with such characteristics. An isolator design is proposed to reduce vibration and shock. Associated random vibration and shock response of the high voltage battery pack are simulated under conditions suggested by MIL specifications. Its dynamic characteristics and vibration and shock responses are validated with experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.291-298
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• 2019

We describe the improvement of insulation performance and the prevention of electrolyte leakage in a single cell in order to prevent the fuming phenomenon caused by leakage of electrolyte in a lithium secondary battery in a submerged weapon (torpedo) operated in Korea. A torpedo using lithium secondary battery as a main power source (propulsion battery) can induce the heat and fuming phenomenon, which makes it inconvenient for naval equipment operation in Korea. In the simulation test, the electrolyte of some battery cells leaked in the battery pack unit, leading to a short circuit between the main power circuit and the terminal tab of the high voltage part. We analyzed the characteristics and mechanism of the lithium secondary battery during this heat generation and fuming phenomenon. In order to prevent leakage of the electrolyte in the lithium secondary battery, the design was improved via fundamental (terminal tap enhancement) and complementary (insulation block selection and installation) measures. Comparison of the performance test before and after the improvement showed that the tensile strength of the tap terminal was improved about 2 times and the withstand voltage characteristic was improved. The application of quality improvement measures resulted in no fuming even after more than 3 years of field operation. This result is expected to improve the operation and storage stability of the torpedo propulsion cell.