Should you’ll recall, in the course of the excessive warmth exams, the pouch surrounding Donut’s battery misplaced its vacuum seal. This led to researchers at Finland’s state-owned VTT Technical Analysis Centre, which performed all the lab’s earlier exams, to discover whether or not the cell may nonetheless operate underneath these high-stress, high-temperature situations. As Donut notes, injury similar to what was sustained by its pack in the course of the warmth check has been identified to trigger hearth or thermal runaway in standard lithium-ion batteries. The startup needed to see whether or not its solid-state battery may keep away from the same calamity.
Researchers performed three exams: a baseline check of 5 cycles at 1C (26 amps); a high-stress check of fifty cycles at 5C (130 amps); and one other closing baseline check of 5 cycles at 1C to measure degradation. After the exams, the staff noticed a pointy drop in vitality capability, from 24.7 amp-hours to 11.2 Ah, or a lack of roughly 55 p.c. Additionally they recorded a drop in effectivity from 89.6 p.c to 83 p.c, and famous a 17 p.c improve within the pack’s thickness.
Given the injury sustained by the pack, the outcomes shouldn’t be that stunning. The lack of the vacuum seal definitely accelerated the battery’s degradation and contributed to its thick, swollen state after the check. Nonetheless, Donut Lab mentioned this was additional proof that its battery can keep away from among the worst outcomes of a broken lithium-ion battery.
“No temperature spikes, no hearth danger,” the corporate mentioned on its IDonutBelieve.com web site. “On this state of affairs the Donut Battery fails gracefully when broken, persevering with to function safely at decreased capability slightly than posing hazard to the consumer.”
However the exams additionally signify the closest that Donut Lab’s battery has come to a cycle check — and it was underneath these broken situations. The startup has but to exhibit how its pack holds up underneath an accelerated growing older process that repeatedly expenses and discharges the cells to guage their long-term efficiency and security. Donut has beforehand claimed its solid-state battery can final 100,000 cycles, which might signify roughly 270 years of charging and discharging. This could be orders of magnitude better than the 1,000-2,000 full charging and discharging cycles that the common EV battery can face up to earlier than its capability begins to degrade.
And extra importantly, Donut has but to ask for an unbiased verification for its claimed 400 watt-hours per kilogram of vitality density. That looks as if a easy sufficient check — all you need to do is weigh the cell and measure its output — and it’s unclear why Donut Lab hasn’t requested for it but.
We’ll have extra to say about Donut Lab’s exams and what unbiased consultants are saying in regards to the startup within the weeks to return.
