The droplet quantity of the inkjet head used for the new technology is 7 picoliters on average. If the size of active materials is too large, droplets do not come out of the nozzle, or the nozzle will be quickly clogged. On the other hand, if the size is too small, the active materials clump together.
To prevent this, Ricoh dispersed particles with its own technology and realized an ink containing materials. At the same time, the company succeeded in developing a separator ink.
The current problem of the new technology is that the production efficiency using the printing method is low. Compared with conventional methods that apply electrodes, the amount of battery materials that can be formed at a time by printing is limited. Therefore, to realize an equivalent battery capacity, it is necessary to print materials several times by stacking them or slow printing speed at the time of forming a film.
"We will use the technology for applications that do not require a cost competitiveness much by taking advantage of its capability to form a desired shape," Ricoh said.
To improve production efficiency, Ricoh plans to review the shape of the inkjet head, optimize it for printing battery materials and increase printing speed.
Ricoh aims to realize a "perfect on-demand production" that uses an inkjet technology to form an entire rechargeable battery including its package in two years. Until then, the company plans to make proposals for partial commercialization of the technology such as the introduction of the separator printing technology in a conventional battery manufacturing process.