CBI Technical Program results: Better batteries on the road 

Did you know that there is a lead battery in nearly every vehicle on the road today? Lead batteries are crucial for the automotive industry, with 12 V lead batteries being used for SLI (starting, lighting and ignition), start-stop and micro-hybrid applications. According to Avicenne Energy (CBI’s Market Report 2023), the 12 V lead battery market for automotive applications is expected to grow from US$ 16 Bn in 2020 to almost US$ 25 Bn in 2030.  

The Consortium for Battery Innovation (CBI) contributes to the growing demand for high-performing lead batteries by funding pre-competitive research as part of our Technical Program, based on research priorities defined on CBI’s Technical Roadmap. For automotive applications, research focus is on the following performance metrics and electrochemical properties: 

	Dynamic charge acceptance (DCA): the ability of a battery to accept instantaneous energy during charging
	Hydrogen evolution reaction (HER): the side reaction occurring on a negative electrode surface which accelerates water loss
	Cold cranking amperage (CCA): the high discharge pulse power responsible for starting a car, rated at -18 °C for 30 seconds
	High-temperature durability: the ability of a battery to perform at higher temperatures, measured by standardised overcharge tests typically above 60 °C

In the project ‘Investigations on the effect of carbon surface functional groups on electrochemical behavior of lead-carbon electrodes’, finalised in March 2023, Fraunhofer Institute for Silicate Research and Wrocław University of Science and Technology have collaborated to investigate the influence of different types of carbon additives on the performance of negative electrodes in advanced lead batteries. The base of this study was the application of chemical modifications to two different amorphous carbons with low and high external surface areas to obtain a range of acidic and basic carbons for testing. Their key finding was that specific surface functional groups of carbon can increase DCA while lowering HER activity and improving CCA. 

Completed in September 2023, the project ‘Best practices of cell testing for EFB regarding DCA and high-temperature durability’ brough together four German partners – Technical University of Berlin, Fraunhofer Institute for Silicate Research, Moll Batterien and Ford Aachen – in a collaborative effort to establish improvements to laboratory test methods for 2V lead battery test cells during battery use in automotive applications. They have successfully defined best practices for measuring weight loss and electrolyte decomposition with 2V laboratory cells during standard tests, and for test cell design and sealing to account for the harsh conditions at high temperatures. These results provide guidance for better optimization of active material formulation for automotive batteries. 

Lessons learned from previous projects about carbon surface functional groups and laboratory cells are not only relevant to 12 V lead batteries, but also for the growing use of lead batteries in auxiliary mode. Because of the nonstop evolution in automotive technology, auxiliary batteries have been increasingly employed for safety back-up and supply power to specific electronic features, being a significant opportunity for low-voltage lead battery systems. 

Helping to build up that knowledge for this significant emerging market, one new project kicked off in 2023 focusing specifically on auxiliary automotive use. The project ‘In Situ Imaging and Phase Analysis of Live Cell Lead Battery Materials for Auxiliary Battery Cycling Regimes’ is investigating processes occurring at microscopic level during representative tests for auxiliary batteries to understand how positive and negative electrodes change during different charge conditions. This study will link laboratory findings to commercial lead battery products, having large potential to improve performance metrics of lead batteries used in auxiliary applications.  

If you want to know more about the findings of pre-competitive research projects supported by CBI, the full detailing of results is available for CBI members.