Allotrope Energy has developed a class of supercapacitors with twice the energy density of current technology “in a package half the weight, half the size and at a fraction of the cost of existing solutions”, the company says. The company says the supercapacitors could form the basis of a new generation of hybrid powertrains that recover far more energy and provide greater power assistance, yet at a substantially reduced cost and with easier integration.
Supercapacitors are able to store energy much faster than batteries, making them ideal for use with regenerative braking systems in hybrid-electric vehicles. However, their relatively low energy density to date has limited their adoption by automotive manufacturers, which have instead had to rely on more conventional battery technology.
Allotrope’s latest technology uses Lignavolt, a sustainably produced nano-porous carbon with a large surface area. While typical supercapacitors have an energy density of around 7-8Wh/kg, Allotrope’s supercapacitors have demonstrated 14-15Wh/kg in third-party verification, enabling double the performance at a lower cost.
“Harvesting 100% of the energy available during even moderate braking would require a lithium-ion battery so large that it would be both impractical and cost-prohibitive,” explained Dr Peter Wilson, CTO at Allotrope Energy. “The ability to deal with sudden surges of power safely is still beyond most battery technologies, and so they limit themselves to effectively skimming off the top. By contrast, a Lignavolt-based supercapacitor could recover all of that energy instantly using a pack the size of a shoebox weighing only a few kilos.
“Supercapacitors can also deliver power quickly, and that opens the door to more powerful electric motors that provide greater assistance. A 1kg Lignavolt supercapacitor could provide 75bhp of electrical assistance – 50 times that of an equivalent lithium-ion battery. That allows much more of a powertrain’s acceleration to come from the electric motor, which in turn can then be matched to a smaller, lighter combustion engine, introducing even further fuel and emissions savings. In fact, doubling the output of an average ICE-powered family SUV would require a supercapacitor that weighed no more than 4kg.”
The company has said that the supercapacitors are stable, require no complex thermal management and their lifespan is greater than batteries, even during heavy-duty use. In terms of manufacturing, supercapacitors do not require rare earth materials – Lignavolt, the primary material in Allotrope’s supercapacitors, is refined from a co-product of the pulp industry, making it a sustainable material.
Allotrope has already begun providing evaluation cells to industry partners, with positive results pointing toward their use in automotive applications.
In related news, 24M Technologies has developed an electrolyte, called Eternalyte, designed to enable faster charging and maintain performance in low-temperature conditions. Read the full story here
