Donut Lab은 전고체 배터리 주장에 대해 방어적 입장을 취하고 있습니다.

This past January, Donut Lab sparked a worldwide battery controversy at CES 2026 by announcing it had developed a solid-state battery for a forthcoming Verge electric motorcycle. The Finland-based Donut claimed a commercial breakthrough that has eluded the world’s largest battery companies or start-ups, whether China’s CATL, BYD, Factorial Energy, or Quantumscape. Skeptics have looked to blow a hole in Donut’s claims ever since. Yang Hongxin, chairman and chief executive of Chinese battery maker SVOLT Energy, did not mince words. “That battery doesn’t exist in the world,” Hongxin told local media after the company’s Battery Day in January. “All the parameters are contradictory…any technician with basic knowledge would recognize it as a scam.” Donut, which previously garnered attention for its hubless in-wheel electric motors, has met the doubt with defiance. In an interview with IEEE Spectrum, Ville Piippo, Donut’s co-founder and CTO, acknowledged natural skepticism toward a company with no proven track record in batteries. “If the world is pouring billions and billions of dollars into solid state, why haven’t they figured this out?” Piippo asked rhetorically. “The answer is the same as for our motors, that we are doing things a different way, and the rest of the world has focused on the wrong thing.” The company has launched a website, idonutbelieve, to directly address the backlash and company critics. To help back its claims, the company began posting a video series on 23 February that highlights third-party testing of its technology by the state-owned VTT Technical Research Centre of Finland. Extraordinary Claims Require Extraordinary Evidence The claims are dramatic. Donut says its solid-state battery can charge to 80 percent of capacity in as little as five minutes, endure 100,000 cycles and deliver 400 watt-hours per kilogram of energy density, versus the 200-300 Wh/kg of typical lithium-ion cells. With no liquid electrolyte, the solid-state batteries should be virtually immune to thermal runaway. Donut is a spin-off of Estonia’s Verge Motorcycles, whose Verge TS Pro was expected to begin shipping to customers in the first quarter of 2026, with up to 600 kilometers (370 miles) of riding range from its larger, optional 33.3 kilowatt-hour pack. Independent testing by VTT in recent months is backing some company claims, including for blazing charging speeds. But Eric Wachsman, a solid-state battery expert and director of the Maryland Energy Innovation Institute, says the tests raise as many questions as they answer. To name two, the company has still not revealed the chemistry inside the cells, and the test did not weigh the cells to determine energy-density figures. “They’re quoting 400 watt-hours per kilogram, but nothing here is telling me what the masses or volumes are,” Wachsman says. VTT tested a Donut pouch cell with 24 amp-hours, a nominal voltage of 3.6 and nominal energy of 94 watt-hours. Cells were charged at both 5C and 11C rates. These designations are based on a 1C rate, which means the battery can be fully charged in 1 hour. 5C means the battery can be charged in 1/5 hour, or 12 minutes. Tests were conducted with passive aluminum cooling plates, both single- and double-sided, to simulate thermal management in an EV. The 5C test zapped the cell with 130 amps at 4.3 volts, and achieved an 80-percent charge in 9.5 minutes, and 100 percent in just over 12 minutes. Peak temperature reached 47 degrees ºC (116.6 degrees ºF). The same cell was then charged at an extreme speed of 11C, which showed a 0-to-80 percent charge in 4.6 minutes—which validated Donut’s claim that the battery can be charged from zero to 80 percent within 5 minutes. The VTT test further indicated a zero to 100 percent charge at 11C in just over seven minutes. Temperatures reached 63 ºC (145 ºF). A subsequent discharge and charge left the battery with up to 99.6 percent of its original capacity available. Seven Charge-Discharge Cycles Tested, 99,993 To Go Wachsman notes the cells were only tested over seven cycles. That doesn’t begin to prove the cells could last hundreds or thousands of cycles—let alone the 100,000 cycles that Donut claims, which is exponentially more than the 2,000-3,000 full charge-discharge cycles typical of the lithium-ion batteries now used in EVs. A second test measured the cell’s performance under high-temperature conditions. Those tests raised more red flags with Wachsman, including graphs that suggested an unimpressive round-trip-efficiency (RTE); or the ratio of useable energy retrieved during discharge, versus the energy inputs during charging. The tests showed roughly 90-percent RTE, including a cycle that delivered 99.97 watt-hours of charge, and 90.36 watt-hours of discharge energy. Designers of solid-state batteries are aiming for RTE’s of 98 percent or higher, due in part to their inherently lower internal resistance. And while Donut has claimed its batteries don’t exhibit much volume change