Roundtable Discussion
All-Solid-State Batteries Supporting Spacecraft Missions:
Taking on the Challenge of Harsh Space Environments through Joint Research with JAXA
In 2026, Maxell’s proposed theme, “Development and Demonstration of High-Heat-Resistant All-Solid-State Batteries to Maximize Spacecraft Missions,” was selected for the Japan Aerospace Exploration Agency (JAXA)’s public-private co-creation program, “JAXA-STEPS*.” Maxell and JAXA have begun joint research aimed at using all-solid-state batteries to reduce the overall weight of small satellites and enhance design flexibility, even in the harsh environment of space. A small battery can have a major impact on the design and operation of an entire spacecraft. This is the start of collaboration that truly embodies Maxell’s corporate byline, “Micro batteries. Maximum impact.”
*A program that accelerates research and development by using small satellites to conduct quick, timely demonstrations of future missions and technologies needed by both the public and private sectors. In its inaugural fiscal 2025 call for proposals, 7 of 24 proposals were selected, with Maxell chosen in the “Feasibility Study (FS) Phase / Miniaturization and Modularization-Related Technologies” category.
All-solid-state batteries excel under constraints: A project launched targeting space use
TaniguchiThe main mission of this project is to develop a large all-solid-state battery that can serve as a primary power source in space. The characteristics required include high energy density, heat resistance, and low-temperature performance. We’re starting by selecting, procuring, and evaluating battery materials to find the optimal combination. Some of the requirements and design considerations for a space-grade battery are still not fully clear, so this project lets us receive design guidance from JAXA while working together on evaluations specific to the space environment, such as radiation exposure.
KawaseWe want Maxell to fully demonstrate its technical capabilities, while we align our requirements for the battery with the experience and knowledge we’ve built up through our own development work. Our first goal is to use it as the primary power source for small satellites.
From a “sheltered life” to a battery built to survive harsh environments: Aiming for demonstration in space by 2029
YamadaRight now, satellite batteries are carefully kept inside boxes held at around 20°C ± 10°C. That requires dedicated equipment to maintain the temperature, which in turn consumes a great deal of power. If we can create a battery that doesn’t need this kind of “sheltered life” and can survive in harsh conditions instead, temperature-control equipment can be simplified, and the design effort that goes into managing heat can be reduced as well. That also translates directly into weight savings. Launching a payload into space costs about 1 million yen per kilogram, and getting it to the Moon costs about 100 million yen. The lighter the battery and equipment, the better, and all-solid-state batteries could lead to a major reduction in the overall weight of the spacecraft.
KamizoriRight now we’re working to triple that 20°C ± 10°C range, while still preserving the inherent safety that is one of the defining characteristics of all-solid-state batteries.
KawaseIf we can achieve that, it will substantially increase the design flexibility of the satellite itself.
YamadaDown the road, our thermal design work might disappear altogether (laughs). Also, once a satellite is in space, there’s no way to perform maintenance on it, so being maintenance-free matters just as much.
KawaseA wider standard operating temperature range also makes the battery easier to handle during ground operations before launch. Under the JAXA-STEPS framework, we’ll spend a year on a feasibility study covering both battery development and the value it can deliver, and if that looks achievable, the space demonstration stage will follow over roughly the next two years.
KamizoriYes. We plan to complete technical verification in the first year, then increase the battery’s capacity over years two and three.
TaniguchiThe materials Maxell uses offer very high levels of safety, which I think makes them well suited to the space environment. At the same time, energy density is not yet on par with lithium-ion batteries, so we need to revisit our materials to raise energy density per unit weight. There are trade-offs involved, since changing the materials can reduce heat resistance, so we’ll be working to increase capacity while balancing heat resistance against energy density.
Two or three steps ahead of the times: Batteries built for space, and for extreme environments on Earth
KawaseWhen I visited Maxell’s technology gallery, I learned that Maxell had released a portable cassette tape recorder and player, the Gemphon, back in 1958, earlier than the famous Walkman. That left a real impression on me: this is a company whose culture puts it not just one step ahead of its time, but two or three. I’m hoping all-solid-state batteries will be out in front in the same way.
YamadaEveryone at Maxell has a personality that really makes me feel that I’m dealing with people who develop truly refined batteries. They’re highly motivated, and easy to communicate with.
KamizoriWe’ve been able to speak frankly with each other about whatever’s on our minds.
KawaseOnce this battery is completed, I’m hoping we can build on its durability and put it to use in extreme environments here on Earth as well.
YamadaI went to Canada in March, and in the snow, at around minus 20°C, I didn’t see any electric vehicles running. If we can develop a battery that works even in conditions like that, I imagine the range of applications would expand considerably.
KamizoriSpace is a field full of possibility, and I can feel that it’s raising the motivation of Maxell employees. I see this JAXA-STEPS project as a clear signal that Maxell intends to enter the space industry. Looking ahead, I’d be glad to see us contribute to the growing space industry through Maxell technologies beyond batteries as well. And beyond that, I want to take the technology we establish in space and apply it to extreme environments here on Earth, opening up new business opportunities.
TaniguchiThe cooperation of our suppliers has also been essential to this joint development. Working together has strengthened these relationships and helped us grow as engineers. There have been difficult moments in the development process, times when it’s easy to feel discouraged, but everyone at JAXA stays positive even in the toughest situations. I want to follow their example and see this project through to success.
KamizoriAs we worked to expand the market for all-solid-state batteries, I became convinced that their performance truly comes into its own in environments with constraints, such as temperature and maintenance. That conviction led us to focus on space, the harshest environment of all, and in August 2025 we gave a presentation to Mr. Kawase’s team. That’s how this project began.
YamadaI really felt Maxell’s strong enthusiasm. Many manufacturers hesitate when it comes to space, so this was a truly welcome proposal.
KawaseFor our part, we had recognized for about 10 years that the wide operating temperature range and high level of safety of all-solid-state batteries could be put to good use in space, and we had been evaluating samples from several manufacturers.
KamizoriThen, as it happened, JAXA-STEPS was newly established in October 2025, giving us the opportunity to submit a proposal for all-solid-state batteries.
KawaseJAXA-STEPS is a program designed to move public-private collaboration forward more quickly. One major factor behind the selection of Maxell’s project was that Maxell already had a track record of mass-producing all-solid-state batteries.
YamadaAt the symposium held after the selection, I heard Mr. Kamizori explain that all-solid-state batteries can have their characteristics refined to fit a given market, opening up uses that were never possible before. Hearing that, I got excited about the possibility of a battery built specifically for space.
KamizoriWith all-solid-state batteries, we can focus development on whatever characteristics a customer needs, whether that’s extending the usable temperature range or increasing flame resistance. I’m looking forward to seeing just how much value the battery we develop this time can deliver in space.