Experts: Christoph Fässler (Modual), Vincent Marbé (Modual), Philipp Strüby (Modual)
While electromobility is key to reducing greenhouse gas emissions in the mobility sector, it also brings its own challenges – particularly in terms of raw material extraction and battery recycling. An innovative solution from Switzerland could solve these problems: Modual uses used electric vehicle batteries as stationary energy storage systems, thereby contributing to sustainable resource utilisation and optimising renewable energies.
Picture: Modual AG
In Switzerland, mobility and transport account for 33 percent of greenhouse gas emissions – a figure that remains stagnant. However, to achieve the target of net zero by 2050, these emissions would need to be declining. Vehicle electrification is unavoidable. At the same time, experts estimate that, by 2030, over 2 million tonnes of electric vehicle batteries will reach the end of their first life each year. While using these batteries certainly has positive effects on greenhouse gas emissions, it also requires massive and environmentally harmful mining of graphite, cobalt, lithium and nickel. This extraction largely takes place in countries that are politically unstable. Additionally, batteries with a 80 percent residual capacity are no longer sufficient for electromobility and must be replaced. Estimates suggest that, globally, only 5–15 percent of all batteries are properly recycled.
Philipp Strüby and Christoph Fässler, the founders of Modual, recognised that the residual capacity of used electric vehicle batteries is sufficient for stationary energy storage. They began experimenting in a basement in 2020, assembling retired batteries from Kyburz Switzerland’s three-wheeled postal delivery vehicles into storage systems for use in households with photovoltaic installations. The advantage is that these batteries are based on low-flammability lithium iron phosphate, come from a Swiss source and are delivered already dismantled into their cells.
One of the first steps on the path towards founding the company was assembling the cells with sufficient residual capacity to form storage systems. However, for integration into private households with photovoltaic installations, the storage system must also communicate with the inverter and the house, and the battery condition must be monitored. Appropriate electronics and software had to be developed. And the team was successful. The first storage systems were installed in 2021 and teething problems were resolved. Series production began in 2022 and was scaled up in 2024. In total, Modual has already installed several hundred systems in Switzerland with a total capacity of several megawatt hours – all manufactured at the company headquarters in Brunnen.
Soon after developing the first prototypes, an unexpected problem arose: battery availability. Vincent Marbé, CEO of Modual, summed up the issue: “The lifespan of batteries in electric vehicles is longer and their introduction to the market is slower than originally anticipated.” To ensure availability – and thus the company’s survival – spent batteries are now sourced from several suppliers, including a French commercial vehicle manufacturer and an electric bus manufacturer. In future, transport operators that use electric buses and battery manufacturers will also likely be considered as sources of supply.
However, supplier diversification also increased battery variety – not only in terms of shape, design and capacity, but also electronics. To complicate matters further, even identical batteries from the same supplier differ depending on the production series. This requires production flexibility and casing adjustments for the storage systems, not to mention constant further development of the company’s own electronics and software. The 19-person team in Brunnen is rising to the challenge, though, producing storage systems with capacities of between 11.5 and 368 kilowatt hours as plug-in solutions for private households and small industrial applications with photovoltaic installations. The integrated electronics handle communication with the property, smooth load peaks, periodically subject the batteries to “wellness programmes” to optimise their remaining service life, and also monitor battery ageing. Modules within the battery pack that have reached the end of their service life are therefore detected early on and replaced. This also minimises the risk of thermal runaway – a chain reaction where a battery cell overheats and can lead to a fire breaking out or even an explosion.
The company is considering further scaling of storage systems to capacities of 500 kilowatt hours and more. “These are not only of interest for industrial purposes,” remarked Vincent Marbé. “Combining several of these large-scale storage systems into a virtual power plant can make a positive contribution to grid stability.” Distribution grid operators will become a new target group.
In future, batteries should be converted into storage systems where they become available after their initial use in electric vehicles. This eliminates the need for emissions-intensive transport to Switzerland. Brunnen will no longer be the only production site. Following an initial expansion phase in Europe, further sites in Asia and America should follow.
Motivation within the team is high. Every individual has found their niche and calling, and is proud to help shape the future. Studies have shown that, with a guaranteed residual lifetime of at least ten years, the CO2 and resource footprint of storage systems with second-life batteries is significantly lower than solutions with new batteries. Furthermore, battery storage systems enable optimum use of renewable energies. These are yesterday’s resources for tomorrow’s world.
