关键词: 软包电池模组, 能量密度, 体积利用率, 成组效率, 尺寸链

Abstract:

The cell module is the key component of an electric vehicle battery system, providing the energy output for the vehicle. In this study, we describe a lithium iron phosphate (LFP) pouch cell module with high energy density and high safety factor. The basis for improving battery system effectiveness and vehicle driving range lies in enhancing volume utilization and group efficiency. To improve volume utilization and bunching efficiency, we investigated the cell module in detail, both internally and externally. From an external perspective, we considered integration with the battery pack envelopes developed by mainstream vehicle manufacturers. From this analysis, we suggest configurations of cell modules to optimize the utilization of battery envelope space and propose a scheme for increasing the height of standard LFP pouch cell modules. We obtained the maximum pouch cell envelope size using theoretical mathematical formulas. Increasing the pouch cell size allows improved volume utilization in the cell modules, with corresponding increases in bunching efficiency and cell module capacity. We then simulated the lightweight cell module by finite element modeling. Once the simulated strength met the stipulated requirements, reliability experiments (e.g., for vibration and impact) were conducted to assess the safety performance of the cell module. Our conclusions are that the goals of high energy density and high safety can both be achieved, assuming a certain energy density. These findings lay the foundation for future popularization and practical application of LFP pouch cells.

Key words: pouch cell module, energy density, volume utilization, bunching efficiency, size chain