For a more convenient and safer power storage device that answer market demand


The world is now moving towards realizing by 2050 a carbon-neutral society, which is a society in which greenhouse gas emissions are substantially cut to zero, and there are high hopes for “rechargeable batteries.”
Considering the trends of the times, SEL has started research and development of rechargeable batteries from 2009.

If a rechargeable battery existed that could supply more power over a long period of time per charge, the usage of battery-powered products including mobile devices or electric automobiles would expand even more and the convenience would improve.

With safety as our top priority, we strive to research and develop rechargeable batteries with high energy density and long life. Aiming for the ultimate energy storage device, SEL has been thoroughly researched and developed materials and devices that make up batteries to improve battery properties.

Demand for rechargeable batteries are higher than ever for us to achieve reduced-carbon society. SEL will work to improve the technology.


SEL battery R&D environment


SEL has created a fulfilling environment to work on the R&D of a variety of materials and devices that make up batteries as well as on the prototype of complete cells.




Endurance test

Charge-discharge tests are conducted to evaluate performance of batteries, such as endurance.




Battery system for ensuring safety


Battery Protection Control Circuit (BTOS®)

Our aim is highly functional and safety power storage system achieved by the synergistic effect of the battery and the oxide semiconductor (OS) technologies in which SEL has been engaged since 2008.

BTOS[1, 2] is original system constructed by SEL, in which batteries and OS technologies are combined to protect and control the batteries.
BTOS has 10 functions listed below and can be applied to all lithium-ion secondary batteries. The BTOS technology enables, in advance, anomaly detection[1] of micro short-circuit causing ignition and heat generation. This system is a promising technology to prevent accidents due to the batteries.


▲Functions of battery protection control circuit

[1] H.Inoue et al., Int. Solid-State Circuits Conf. Dig. Tech. Pap., 204 (2019).
[2] S.Fukai et al., Ext. Abstr. Solid State Devices and Materials, 707 (2019).


Anomaly Detection with AI for Rechargeable batteries

We are developing safe control system of rechargeable batteries with AI technology.

Artificial Intelligence







*BTOS is a registered trademark of Semiconductor Energy Laboratory Co., Ltd. (Japanese trademark registration No. 6146374).