QuantumScape says its 'Cobra' process makes battery separators 25 times faster

June 2025 — QuantumScape said its Cobra separator process had replaced Raptor in baseline cell production, a step it says clears the way for B1 sample cells. Here's what happened, what it cost, and what went wrong.

Cost and outcome (as of July 23, 2025)

Outcome: Cobra in baseline production, the first of QuantumScape's 2025 goals. (QuantumScape release)
Company claim: about 25 times faster heat treatment than Raptor, in a fraction of the space per film start. (QuantumScape release)
Cost: not stated for Cobra. Q2 2025 capital spending was $8.3 million, mostly for facilities and equipment purchases to prepare for higher-volume B1 sample production. (QuantumScape Q2 letter)
Status: no Cobra-based B1 cells had shipped as of July 23, 2025; field testing targeted for 2026. (QuantumScape Q2 letter)

What Cobra changes

The separator is the ceramic layer at the heart of QuantumScape's solid-state lithium-metal cell. Cobra is a "high-throughput, continuous-flow" process designed for faster, more energy-efficient production with a smaller equipment footprint, the company says. (QuantumScape release)

Raptor, the process it replaces, made the B0 sample cells and "delivered important gains in separator quality and process stability," per the release. (QuantumScape release)

"By significantly improving throughput and shrinking the equipment footprint, Cobra gives us a powerful path forward," said CEO Siva Sivaram. CTO and co-founder Tim Holme called it "a step-change innovation in ceramic processing." (QuantumScape release)

The numbers, all the company's

QuantumScape says Cobra's heat treatment is about 25x faster than Raptor's. (QuantumScape release) Its shareholder letter adds that baseline separator heat-treatment speed improved by "over 200x" across two years. (QuantumScape Q2 letter)

Neither figure has been independently checked. The company's own release warns that results could differ on "speed, quality, consistency, reliability, safety, cost and throughput." (QuantumScape release)

What comes next

QuantumScape is installing higher-volume cell production equipment to keep pace with Cobra. "Production ramps are always challenging," the letter says, naming cell reliability, process stability and equipment uptime as focus areas. (QuantumScape Q2 letter)

In Q2 it shipped the last Raptor-based B0 QSE-5 cells to its launch customer for pack integration and safety testing. Future shipments will be Cobra-based B1 samples, it said. (QuantumScape Q2 letter)

The PowerCo deal

In July 2025, QuantumScape expanded its licensing deal with PowerCo, which will pay up to $131 million more over two years tied to milestones, on top of $130 million due on satisfactory technical progress and execution of the full licensing agreement. PowerCo could make up to 85 GWh of QS cells a year. (QuantumScape Q2 letter)

QuantumScape will prioritize QSE-5 output from its San Jose pilot line for PowerCo work, but keeps the right to supply other customers. It also signed a joint development agreement with another major automaker it didn't name, and is exploring ceramics production with Japan's Murata Manufacturing. (QuantumScape Q2 letter)

The cash

QuantumScape ended Q2 with $797.5 million in liquidity and moved its cash-runway forecast into 2029, six months later than before. It narrowed full-year capital-spending guidance to $45 million to $65 million. (QuantumScape Q2 letter)

Q2 depreciation included about $14.8 million of accelerated depreciation and write-offs of equipment no longer in use; the letter doesn't say which equipment. (QuantumScape Q2 letter)

Its forward-looking-statement cautions list "challenges in optimizing manufacturing processes and scaling up Cobra to enable B1 sample production," including vendor delays and supply-chain disruptions. (QuantumScape Q2 letter)

What went wrong

Only the company has measured it. The 25x and 200x figures have no outside verification. (QuantumScape release; QuantumScape Q2 letter)
Still losing money. Q2 2025 GAAP net loss was $114.7 million. (QuantumScape Q2 letter)
No cars yet. Field testing is targeted to begin in 2026. (QuantumScape Q2 letter)
What we don't know yet: Cobra's yield, and whether B1 shipments happened on schedule.

Our follow-up question for QuantumScape

Have Cobra-based B1 samples shipped, and will any outside party verify the separator throughput?

Sources

QuantumScape, “QuantumScape Achieves Major Milestone: Cobra Separator Process Enters Baseline Production,” June 24, 2025. ir.quantumscape.com
QuantumScape, Q2 Fiscal 2025 Letter to Shareholders (Exhibit 99.1 to Form 8-K), July 23, 2025. sec.gov

Disclosure: [not in copy] Editor placeholder