A statistical analysis of thermal characteristics of 55-Ah large-format LIB pouch cell with different tab-type, tab size, and tab position

Abstract

The non-uniform temperature distribution in large-format lithium-ion batteries (LIBs) can lead to thermal runaway or performance degradation. This study develops a three-dimensional electrochemical–thermal model of a 55-Ah large-format LiFePO4/graphite pouch cell and statistically analyzes the effects of width, height, and attachment positions of the nominal tab (NT), lateral tab (LT), and counter tab (CT) on the temperature distribution. The temperature difference that occurs across the cell is analyzed separately for each design factor through design of experiments (DOE) and analysis of variance (ANOVA). Accordingly, wider tabs reduce the maximum temperature and temperature difference irrespective of the tab type. Taller tabs yield higher maximum temperatures, resulting in a larger temperature difference. Attaching tabs to the edge of the cell increases the maximum temperature and temperature difference. The locations of the negative NTs and CTs do not affect the temperature difference. However, the location of the negative LT increases the minimum temperature, thereby decreasing the temperature difference. The ANOVA revealed that the p-value of the width, height, and attachment position of the positive tab is lower than 0.05 which means the factors strongly influence the temperature difference for all tab-types. Also, the attachment position of the negative tab affects only the LT-type.

Keywords

• Large-format lithium-ion battery
• 3D electrochemical-thermal model
• Statistical analysis
• Tab-type
• Tab size
• Tab attachment position