Evaluation of the effectiveness and limitations of a cell fire extinguisher

• Main Author: Muhammad Adli Adnan
• Other Authors: Chan Wai Lee
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/158557
• Institution: Nanyang Technological University

With the growing popularity of the usage of Personal Mobility Device (PMD) and Power-Assisted Bicycles (PAB) for commuting or even deliveries, comes a substantial amount of use for Lithium batteries. Lithium Batteries such as Lithium Polymer (LiPo) batteries have been one of the choices to power up these devices due to its high energy density and lightweight characteristics. However, due to multiple reasons and negligence from owners, fires involving these batteries are still apparent in Singapore despite the safety measures imposed over the years. A cell fire extinguisher (CFE) developed by Anzene can be embedded within battery packs of devices as the first line of defence. This report establishes refined experimental procedures to produce consistent results to evaluate the effectiveness and limitations of the CFE. It begins with discussing an overcharging method to produce LiPo battery explosions as well as the utilisation of the CFE. Multiple baseline tests have been put through to ensure consistency in the designed experiment setups in terms of repeatability and safety of personnel. Firstly, a 3 cell LiPo battery was used and found success with explosions and constant burning, but soon changed to a one cell due to the vast difference in fire aggression. Next, was to experiment the effects of CFE on a burning 1 cell LiPo battery as well as the different positions that are deemed more effective to suppress the fire. Experiments, subsequently, evolved to emulate what a PMD/PAB fire would be like with the possibility of fire spreading from a single overcharged battery cell to another adjacent one in a battery pack due to thermal runaway. The thermal imager, however, could only read temperatures of up to 683 degrees Celsius and it is speculated that the temperature of these battery fires can go higher. Results from the experiments conclude that the CFE can put out the battery fire in the replicated experiment. Recommendations are given to explore the possibilities of the CFE to mitigate the fire spreading case and test out its limitations with varying battery sizes as well as its effective range from the burning batteries.