# Temperature and voltage effects on the charge and health of lithium-ion battery modules in light electric vehicles

## TL;DR

This study examines how temperature and voltage affect lithium-ion battery performance in light electric vehicles, showing that high temperatures reduce battery health and efficiency.

## Contribution

The study provides empirical evidence on the impact of temperature and voltage on lithium-ion battery modules in light electric vehicles.

## Key findings

- Lithium-ion batteries retain more heat in the central area of the module, especially at higher temperatures.
- Temperatures above 35°C cause accelerated voltage loss and cell charge imbalance, lowering performance.
- A ventilation system is necessary to manage heat in lithium-ion battery packages for light vehicles.

## Abstract

Lithium-ion batteries are an alternative to mitigate environmental impacts in the vehicle sector. However, their performance is limited by degradation during use, downtime, and environmental and operating conditions. This work analyzes the behavior of lithium-ion batteries when used in a light electric vehicle. Specifically, it determines the state of charge and state of health of a lithium-ion battery package when used in a light electric vehicle with a 500–1080 W power rating and a 48 V, 8.8 Ah electric motor. This light electric vehicle underwent a worldwide harmonized motorcycle emissions certification/test procedure, while the lithium-ion batteries were evaluated at 25, 35, 45, and 65 °C. Voltage, amperage, and temperature were measured in real time. A thermographic study was also conducted in which heat transfer images of lithium-ion batteries were taken in different positions. The results show that the lithium-ion battery package retains more heat in the central area of the module. For example, in the 25 °C test, the most critical temperature reading was 29.9 °C. In the 65 °C test; however, the most critical temperature reading was 80.2 °C. The implementation of a ventilation system for the lithium-ion battery package for applications in light vehicles was evident. Lithium-ion batteries were found to be sensitive to temperatures above 35 °C. These high temperatures cause accelerated voltage loss and an imbalance in cell charge, which consequently lowering performance. Therefore, the state of charge and state of health of the Lithium-ion battery package are significantly impacted.

The online version contains supplementary material available at 10.1038/s41598-026-40094-5.