80 Report | CUAV Expo Americas 2023 Although Amprius is best known for its 500 Wh/kg cell design it announced at AUVSI Xponential earlier this year, the company presented a new cell with a different use case at the expo. Katie Maze explained, “This cell has been designed to deliver both high energy and ultra-high power. It has a gravimetric energy density of 400 Wh/kg, an optimal charge rate of 5C, and a maximum continuous discharge rate of 10C. “What also sets this cell apart is its fast-charging capability. During charging, the charge rate can reach 10C, enabling a cell to charge from zero to 80% SoC in less than 6 minutes.” Traditionally, battery cells have had to make trade-offs between power and energy. However, Amprius attributes the unique capabilities of this cell to its proprietary silicon nanowire anode technology. This highly conductive material is grown directly on the current collectors within pouch-type cells through a deposition process. Maze said, “Our nanowire anode technology is 100% silicon, giving us very high energy density. There are no additives or non-active materials; it’s purely silicon. Also, the unique structural properties inside the anode mean our cells don’t swell any more than typical lithium-ion cells during use. “The power delivery of this cell remains consistent even at lower depths of discharge, giving UAVs an extended usable battery capacity and the ability to withstand challenging conditions throughout a mission. In the growing industry of eVTOL aviation, rapid charging and reliable landing power are expected to be foundational elements. “Lastly, we also generate less heat compared to graphite-anode cells, reducing the thermal management burden for pack manufacturers and UAV designers. This reduction translates into a lighter overall battery pack weight, freeing up more space for payloads.” The company has also developed a range of UAS battery packs with Tenergy. Four versions are available, running from one to four strings of cells in parallel, each string composed of six cells connected in series. The smallest pack is hence a 6S1P system weighing 627 g, with 10.6 Ah of energy capacity, 216.24 Wh of energy storage, and measuring 155 x 65 x 40 mm. October/November 2023 | Uncrewed Systems Technology Amprius’ new high-power cell – graphs showing maximum cell temperature versus discharge C-rate and power density versus depth of discharge Amprius’ battery pack, co-developed with Tenergy
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