The Grid 7 E-Mobility Engineering | November/December 2023 PV system proves a good catch A start-up is working in Africa to electrify fishing boats (writes Nick Flaherty). VoltaViewAfrica was set up by a professor from the Fraunhofer research institute in Germany. Photovoltaics generate electricity that is stored in portable lithium batteries that local residents can use as individual power sources, which includes powering local fishing boats. The powerplant is based on a block-building process and consists of two 10 ft container modules with recycled photovoltaic modules and B-grade lithium battery cells from the automotive industry. It was developed by Prof Wolfgang Schade, who heads the Fibre Optic Sensor Systems department at Fraunhofer HeinrichHertz-Institut (HHI), and is technical director of VoltaViewAfrica. One module generates electricity from a 7.5 kWh photovoltaic array, while the other is used for portable water treatment. The electricity is stored in 48 V lithium-ion batteries housed in sturdy boxes and with a storage capacity of 4.8 kWh. The project developed a safety concept for the lithium batteries and sensor technology that enables fully digitised monitoring and control of the battery storage units as well as the entire powerplant. The first operational plant was formally inaugurated and handed over to residents of a fishing village called Balingho, in The Gambia, in June 2023. The fish catch will be kept in a freezer powered by the module, while the villagers gain access to clean drinking water using UV filters. “Thanks to the freezer, we can now store our catch for longer and thus generate a higher profit, tremendously improving our competitive position,” said Jawo, chairman of the Balinghobased fishermen. Upgrading the fishing boats with electric motors also reduces the total cost of ownership by more than 50% compared to the current diesel engines, and reduces local pollution. As the entire system is digitised, CO2 certificates can be used to cofinance investment costs. A Gambian company, Sub-Sahara United Vehicles, is installing a further 10 systems with a total of 50 replaceable batteries across the country over the next 12 months. SOLAR POWER Structural carbon fibre research Researchers at Chalmers University in Sweden have shown how the manufacturing of carbon fibres can be tailored for developing structural batteries (writes Nick Flaherty). They worked with Carbon Nexus at Deakin University, in Australia, to build a variety of fibres that are strong enough to use in vehicles but can also store significant amounts of energy. However, the properties of the carbon fibre vary depending on the process parameters and which precursor is being used. Some types of carbon fibre can be very stiff, but have a far too low a storage capacity, and vice versa. To be able to build efficient structural batteries, the carbon fibre needs to combine a sufficiently high electrochemical storage capacity with sufficiently good mechanical properties. The better the combined properties, the more efficient the battery. How the manufacturing parameters affect carbon fibre’s mechanical properties is well-established, but relatively little has been determined around its electrochemical storage capacity. A key step in the development of structural batteries is to understand how the manufacturing process can be tuned to optimise the multi-functional properties of the carbon fibre. The team explored the properties of carbon fibres made from the same precursor but with different tensions during processing. The research showed that fibres developed using both amorphous and crystalline phases of carbon affect the electrochemical capacity, as higher capacity is achieved by larger spacing in the fibres as well as higher void content. BATTERY MATERIALS Lithium power packs are being used to electrify fishing boats in The Gambia
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