EV battery testing with miniature load cells

Automotive components undergo rigorous testing to meet regulatory standards, guarantee performance and ensure consumer safety. These components continually require investment in innovation to meet the expressed governmental, consumer and commercial use requirements.

One of the vehicle components that is undergoing intense change is the battery. The market is heavily focused on increasing mileage use and life, which includes the shift from single-use lithium batteries to rechargeable lithium-ion batteries. These customer sentiments are noticeable in the growing global electric vehicle (EV) and hybrid electric vehicle (HEV) demands for sustainable and longer-lasting battery solutions.

Customer satisfaction and commercial applications are closely intertwined with a vehicle’s ability to travel longer distances without refuelling or charging. Their demands and changes drive robust test and measurement programs to bring new battery models and designs to market.

In 2021, it is estimated the EV battery market exceeded 38% of total battery sales. As battery costs decrease and technology continues to improve the life cycle, Precedence Research estimates 32% CAGR through 2030. This translates to $46 billion of market share in the US alone, while Asia–Pacific is leading the production of EVs and overall demand for EV batteries. Based on global adoption of electric vehicles, supported by government initiatives and an intense focus on reduced carbon emissions, the EV battery market is expected to continue expanding around the world.

The testing of batteries is growing in complexity with an increase in the number of cells, modern designs, materials, cycles, installation, vehicle models, certifications and charging equipment to name a few. Battery simulation and real battery integration testing are two examples of commonly used T&M programs used to validate battery adaptability and use requirements. In battery testing, accuracy and quality of the measurement devices are vital.

The most common battery types today include lithium-ion, lead-acid, sodium-ion, nickel-metal hydride and others. The market shift to EVs means the lithium-ion battery is the number one battery type today, exceeding all other battery types in 2021. Manufacturers of EVs prefer partnering with OEMs of newer model Li-ion batteries because they are lighter in weight and have higher energy density.

Interface, a provider of force measurement solutions, has long partnered with auto manufacturers and suppliers of various parts and components to provide a large range of automotive industry test and measurement solutions. This includes sensors and instrumentation solutions for the development, testing and performance monitoring of all types of batteries, with growing interest for lithium-ion battery testing. The following details one of many Interface solutions offered to manufacturers.

Case study: EV battery monitoring

Interface was approached by an EV battery manufacturer that required a system to monitor its lithium-ion batteries. Normally, lithium-ion batteries are measured through voltage and current measurements to analyse and monitor the battery life. In consultation with the design and testing engineers, Interface recommended a solution that required installing its LBM Compression Load Button Load Cell in between two garolite end plates, and measuring the force due to cell swelling or expansion. Instead of monitoring through voltage (ICV), this method is based on measured force (ICF).

To monitor the testing, the load cell was paired with the 9330 Battery Powered High Speed Data Logging Indicator. This instrumentation solution provides the ability to display, record and log the force measurement results with supplied software.

Top image credit: ©stock.adobe.com/au/SOUTHWORKS CREATIVE LTD

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