Amprius Rents Its Battery Factories. Every New Plant Has to Be Qualified Again.

Amprius designs silicon-anode battery cells for drones and aircraft, and it has chosen not to own the factories that build them at volume. Its cells come off partner lines in China and South Korea. Today it added one in Indianapolis. CAMINUS, formerly EnPower, will build Amprius-designed pouch cells there. Qualification builds are running now, and volume production is planned for the first quarter of 2027. The arrangement keeps factory capital off Amprius's books and leaves it with a job it has to repeat at every partner: getting each new line qualified to build its cells.

Why Amprius keeps adding plants

Amprius keeps the anode, the cell design, an R&D lab and a pilot line in Fremont. It describes contract manufacturing as a way to add capacity quickly with little capital of its own. The government is now paying for more of that capacity. On September 28 the Department of War awarded Amprius a grant of up to $75 million through its Industrial Base Analysis and Sustainment program. The money converts a US electric-vehicle battery line, run by a South Korean manufacturer, into a line for drone cells. Amprius puts the conversion at about $100 million, including in-kind contributions from both companies, and expects the line to reach 12 million cells a year by early 2028.

Both new sites serve the same buyer. Drone programs need cells that meet the domestic sourcing rules in the National Defense Authorization Act. Amprius calls the converted line a primary domestic source, and CAMINUS says its plant supports a supply chain that conforms to the act's Section 842. The same cell design now has to be qualified on two more lines within about a year.

Qualification restarts at every plant

CAMINUS says cell formats will move into production in stages, ordered by each format's volume and its qualification status. Customers approve cells made on a particular line, with a particular coating process and formation recipe. A new plant means new builds, new test data and a new sign-off for each format it takes on. Under the deal, CAMINUS will do anything from partial assembly of components Amprius ships in, up to full cell production.

Amprius's grant announcement warns that cell performance shown in testing or in limited quantities may not hold at commercial volume, which is the question every new line has to answer during qualification. It also warns that Amprius relies on partners to meet the grant's milestones, so the answer comes from plants it doesn't operate.

What to count before you sign

Medical devices work the same way. Move a cleared device to a new contract manufacturer and the process has to be validated again before the first unit ships. When a founder brings me a plan built on contract manufacturing, I ask for three numbers: how many months a new line takes to qualify for the strictest customer, what the builds and testing cost, and how many product variants can move at once.

I also ask who owns the qualification records. The process parameters, build records and test data from one plant are what let the next plant start from a file. If they sit only in the partner's quality system, the product can't move without starting over, and the business runs at the partner's discretion. Ownership of those records belongs in the contract, next to the qualification schedule.

Dave Saunders is the founder of Base Reality Group and a Fractional CPO for product companies. He was a founder and operator at Galen Robotics, where the surgical-robotics platform earned FDA De Novo authorization in 2023, and he managed a 35-patent portfolio licensed from Johns Hopkins. He wrote Founders Who Finish and publishes The Build. More about Dave →