Reliability Testing for Lithium-Ion Batteries for Electric Wheelchairs

摘要

Compared with the general population, people with physical disabilities have significantly diminished ability to perceive the environment and are therefore at higher risk of missing warning signs of imminent fire or explosion, resulting in a lower chance to escape. This poses a serious threat when they use mobility scooters (motorized wheelchairs). With the scooter frames becoming smaller, lighter, and more convenient in recent years, various types of foldable mobility scooters have emerged. Along with this trend, conventional lead-acid batteries have been increasingly replaced by lithium-ion batteries in a wide range of products. This implies that people with physical disabilities are constantly exposed to the risk of lithium battery fires and explosions. Against this background, this study was conducted to establish reliable test profiles for safety testing for lithium batteries used in mobility scooters by experimentally examining vibrations and mechanical shock while riding a mobility scooter. Random vibrations and mechanical shock are test items for lithium-ion batteries as part of reliability testing for automobiles and motorcycles. However, they have not yet been developed as test items for mobility scooters. In an effort to bridge this gap, the acceleration, velocity, and impact force working on a lithium-ion battery mounted on a mobility scooter while driving by simulating driving conditions were calculated, and the safety test profiles were determined by performing on-road driving tests and impact tests. Then, the reliability of the test data was verified in a statistical validation process. The safety of the test profiles established in this study was tested and verified in a nationally accredited testing laboratory. As a result, the lithium-ion battery mounted on the mobility scooter was found to have incurred no leakage, short circuit, burst, or explosion. The vibration and mechanical shock test profiles proposed in this study are expected to serve as basis data for establishing standards for mobility scooter safety and reliability. The vibration and mechanical shock test profiles proposed in this study are expected to serve as basis data for establishing standards for mobility scooter safety and reliability. If the lithium-ion battery reliability test items can be added in a follow-up study based on the results of this study, it will provide great momentum to establishing safety and reliability standards for the safety and reliability of mobility scooters, greatly contributing to enhancing the traffic safety and quality of life for vulnerable road users.