A longer range on the road means no more vehicles stopping to charge. At sea, it means solar-powered boats can be energy independent. Range is significantly reduced by battery age, heat, and cold, so a greater margin of error is truly invaluable.
The increase in energy density involves packaging, not just cell chemistry. New options are facilitated by longer-lasting batteries; a million-mile battery is on the horizon. Two approaches are favored to simplify the cell-module-package approach, reminiscent of supermarkets over-packaging food. Tesla is enlarging its cylindrical module and abandoning the pack by permanently sealing them into a large structural part of the chassis. This is a great idea for a vertically integrated company like Tesla. It's much more difficult for traditional OEMs who need to deal with suppliers. There are also issues surrounding second-life and recyclability.
However, General Motors appears to be moving in this direction as it becomes more vertically integrated. Its Ultium battery uses a modular system called a cell-module assembly (CMA). The cells and modules remain the same, with the module combination and pack design changing depending on the vehicle, aiming to allow for rapid entry into different vehicle segments. The CMA provides a mechanical structure to the vehicle and is the primary power connection between the cells and the drive system. The modules have been designed to accept both pouch and prismatic cells.
In the alternative no-module approach, MCLA claims to have offered bag cells since 2012. CATL, BYD, and LG Chem will soon follow suit in mass production. Improvements of up to 30% in vehicle weight and range are cited. LG Chem has completed the development of its Module Pack Integration Platform. It will reportedly accommodate twice as many cells as conventional module platforms. Here, the cost can be reduced by 30%, and energy density increased by 10%. These are significant gains in terms of sales capacity and resale value for the vehicles that use them.
Does it stop there? Supercapacitors are packaged much like batteries and have replaced many lithium-ion batteries in hybrid microcars. Geely has made a major commitment to large supercapacitors, partially replacing batteries in its mild and full hybrid cars, and Skeleton Technology claims a $1 billion letter of intent from a major automaker. In terms of enclosure, supercapacitors have an advantage in not swelling and shrinking during cycling, so a Lamborghini lab with MIT is developing a module-less, envelope-less, self-regenerating supercapacitor body. Imperial College London is competing, coining the term "massless energy," meaning a vehicle that doesn't dedicate space or weight to energy storage because the body becomes dual-purpose. Later versions of solid-state batteries are expected to be cycle-stable, so guess what might come next.
Author: Dr Peter Harrop, Chairman of IDTechEx
