[SIS6] Industrial Application of Functional Materials

[16C-SIS6-01] Special Invited: Development of New Powder Magnetic Core Technology to Achieve Miniaturization and High Performance of Reactors for Electric Vehicles

*S. Saigusa¹, M. Suzuki¹, K. Ishii¹, M. Ohtsubo², N. Iwata¹, T. Ogawa³, S. Ohira⁴, T. Hattori² (1.TOYOTA MOTOR CORPORATION, Japan, 2.TOYOTA CENTRAL R&D LABS., INC, Japan, 3.Daido Steel Co. Ltd., Japan, 4.FINE SINTER CO., LTD., Japan)

Keywords:powder magnetic core, reactor, Fe-Si-Al, Al2O3, insulating film

We have developed Fe-Si-Al powder with Al2O3 insulating film and a new powder magnetic core made by molding and annealing this powder for reactors used in electric vehicles. In this magnetic core, Al2O3 film on the surface of powder particles performed the magnetic resistance function that conventional gap spacers had, and achieved the targeted linear magnetization curve. This has made the reactor smaller, lowered power loss, and reduced parts. The raw material Fe-Si-Al powder was made low loss by applying gas atomization technology, and the film thickness of Al2O3 was made uniform by a new method based on metal vapor phase reaction process. Furthermore, the strength of the core was significantly improved, which was achieved by mixing a small amount of glass powder and molding the core, then melting and hardening the glass during annealing. This product has been adopted from vehicles released on the market in 2022.