Development of AC Internal Heating Techniqeu Utilizing Power Converters Existing in Electric Vehicles

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03996
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21010:Power engineering-related
• Research Institution: Ibaraki University
• Principal Investigator: Masatoshi Uno 茨城大学, 理工学研究科(工学野), 准教授 (70443281)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 電気自動車 / 加熱 / バッテリ / 寒冷地 / インバータ / 電力変換 / コンバータ

Outline of Final Research Achievements

For electric vehicles in cold regions, heating is essential to prevent the characteristics of lithium-ion batteries (LIBs) from deteriorating. AC internal heating is attracting attention as a highly efficient method. However, this requires a separate inverter, which complicates the system. In addition, conventional AC internal heating methods using triangular or sine wave currents suffer from long heating times due to low effective current values.
In this study, we developed an AC internal heating method that uses the existing power converter in electric vehicles. Through actual testing using a prototype circuit, we demonstrated that in addition to the original power conversion function, the battery can be heated from around -10 degrees Celsius to 0 degrees Celsius in just a few minutes.

Free Research Field

パワーエレクトロニクス

Academic Significance and Societal Importance of the Research Achievements

寒冷地ではバッテリ性能が大幅に劣化することにより航続距離が半減することが報告されており、寒冷地での実用化に際して加熱技術は不可欠である。電気自動車に既存する電力変換器を利用することで最小限の追加コストで加熱機能を付加することができるため、本技術により電気自動車の寒冷地における実用性を大幅に高めることができる。