Gas phase composition of a NiMH battery during a work cycle
Aleksandra Lindberg1, Björn Eriksson1, Jenny Börjesson Axén1,2
1Applied Electrochemistry, Department of Chemical Engineering, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden gnli@kth.se.
RSC Advances
|June 24, 2024
Summary
Researchers developed new methods to analyze gases inside Nickel Metal Hydride (NiMH) batteries. Hydrogen gas increases with charge, offering insights into battery performance and potential improvements.
Area of Science:
- Electrochemistry
- Materials Science
- Analytical Chemistry
Background:
- Gas evolution in batteries reduces efficiency and lifespan.
- Quantitative gas analysis is crucial for understanding battery reactions.
- Measuring gases in closed battery systems like Nickel Metal Hydride (NiMH) is challenging.
Purpose of the Study:
- To develop and validate methods for analyzing internal gas composition in NiMH batteries during cycling.
- To correlate gas evolution with battery operating parameters (voltage, pressure, temperature).
- To investigate the impact of charge depth on gas composition.
Main Methods:
- Developed two mass spectrometry (MS)-based methods for in-situ gas analysis.
- Method 1: Connected battery module via a sampler system.
- Method 2: Direct connection using a microcapillary for continuous measurement.
Main Results:
- Identified nitrogen as the most abundant gas, followed by hydrogen.
- Observed a significant increase in hydrogen pressure with increasing depth of charge (DOC).
- Detected low oxygen levels, except near the end of charge.
Conclusions:
- The developed MS methods reliably measure NiMH battery gas composition without adverse effects.
- Hydrogen evolution correlates with the depth of charge, providing insights into battery state.
- These methods are adaptable for analyzing gas evolution in other battery chemistries.
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