The background story of adopting the all-solid-state battery

Toyama: Nikon has previously adopted our heat-resistant coin-type lithium batteries, and had business relations with the digital camera division as well.

Abe: 2019, when we were developing the product that was the precursor to the M700MFA, due to the connection we had in using Maxell’s heat-resistant coin-type lithium batteries, we had the opportunity to engage from an early stage in the development of this product, as well.

Tokiwa: We started considering the specification for the encoder from the winter of 2022. There was a trend of making encoders maintenance-free, and we wanted to get rid of the work involved in removing and changing external batteries for industrial robots. In response to this need, Nikon resolved the issue by incorporating batteries into the encoder’s circuit board. Maxell’s all-solid-state batteries, which are small in size, fit the requirements perfectly by meeting the criteria of environmental resistance, a wide temperature range, long life, and safety.

Abe: There were plenty of opportunities for engineers to talk to each other, and we were provided with information on the characteristics of the all-solid-state batteries. In response to the specifications required by Nikon, we were proposed to use reflow-mounting with ceramic packaging, which allowed us to realize Nikon’s unique maintenance-free encoder.

Toyama: We achieved really great communication in terms of both the sales and design teams, and were able to advance the project with an understanding of each other’s situations. We cleared mutual hurdles through detailed discussions, and created a product that is usable in extremely harsh environments, which I’m happy about.

Sato: Nikon had used Maxell products in the past, and had a certain understanding about our batteries, so it was easy for us to understand each other. In addition, Maxell is promoting the development of all-solid-state batteries based on our policy of solving social issues. Nikon aimed to make this product maintenance-free, and we were moving in the same direction, so we were able to carry out development smoothly.

The advantages of the encoder incorporating the all-solid-state battery

Sato: All-solid-state batteries have four advantages i.e. “high safety” due to the absence of flammable materials, eliminating the risk of ignition or explosion, “wide temperature range” as the solid electrolyte prevents freezing or evaporation of the electrolyte that can occur with liquid electrolyte solution, “surface mountability” with the positive and negative terminals on the same side, making it easier to integrate into the circuit board, and “long lifespan.” These characteristics were suited to the environments in which encoders are used and the challenges they face.

Tokiwa: When attempting to create maintenance-free encoders, it is often difficult to avoid an increase in size. However, taking advantage of Maxell’s all-solid-state batteries being small, we were able to develop a product with an unprecedented thinness.

Abe: When it came to charging, we used a system in which the charging of encoders automatically starts when the main power is turned on. Even in such a harsh environment, with the batteries always close to fully charged, the long life that Nikon seeks had been realized.
　Furthermore, when making proposals to our customers, we consulted on the presentation of proposals and various data graphs, allowing us to effectively convey the high reliability of this new battery technology to our customers.

Looking back on development

Tokiwa: When we first adopted the all-solid-state batteries for this project, there were a lot of parameters, including deterioration due to charging, which made things complicated, but Maxell gained a deeper understanding of factors such as the development background and usage environment, and we were able to carefully confirm each other’s aims and move forward, which gave me a sense of comfort.

Abe: Although we are in different companies, we shared a common desire to expand into new worlds, and were able to move forward with the sense that we were on the same team. The concept of the battery characteristics was complex, and we struggled to integrate that into the specifications of the encoder. However, it was beneficial that both companies went deep into worst-case scenarios, conducting extensive discussions.

Sato: We worked closely as a team that faces challenges together, and were able to create a relationship where questions could be immediately addressed. With Nikon’s requirements, such as “10-year life at 105°C” and “obtaining the necessary battery data to determine the encoder’s specifications,” we also gained an understanding of the battery characteristics required for the FA industry, and incorporated them into specifications, leading to its commercialization.

Toyama: Maxell’s entry into the FA industry was nearly for the first time, but working with Nikon, a top manufacturer of encoders, has provided us with huge learnings about the difficulties of this industry.

Expectations and outlook for all-solid-state batteries

Tokiwa: In November 2023, we displayed the product at the International Robot Exhibition, and it seemed that commercialization of a product using all-solid-state batteries made an impact, resulting in numerous inquiries from domestic and overseas customers. We are at the stage where customers are evaluating our samples, and we plan to start mass production in the spring of 2025. As the MAR-700MFA has a wide temperature range and is compact, we expect it to replace other companies’ products in the future. Right now, only Nikon makes and sells an encoder with a built-in battery. I think that demand for all-solid-state batteries will rise steadily if the M700MFA becomes the mainstream for maintenance-free products.

Sato: Going forward, it will be crucial to explore and expand the market extensively. We aim to continue our strong partnership with Nikon and work together to achieve our goals.

Toyama: We’ve had inquiries from a wide range of fields in addition to the FA industry, including for sensor devices and devices that currently use coin-type primary batteries as backups, and will develop these with each component manufacturer. With regard to mass production, we have finished introducing equipment in our Kyoto Works, and will go ahead with the preparations to supply Nikon in this fiscal year. From the perspective of the SDGs, we’d like to emphasize that our all-solid-state batteries being used as a key device can add new value, such as making products maintenance-free.