Selected as high voltage junction box supplier for the Isuzu ELF EV

Furukawa Automotive Systems Inc. (Headquarters: Inukami-gun, Shiga Prefecture; President: Shigenobu Abe), a member of Furukawa Electric Group, utilized its accumulated technology in the automobile electrical wiring product business to realize a smaller converter box and high voltage junction box and started deliveries of these products for the ELF EV, a BEV ^{(note 1)} truck manufactured by Isuzu Motors Ltd. (Head office: Yokohama, Kanagawa Prefecture; President and COO: Shinsuke Minami; hereinafter “ISUZU”).

The ISUZU ELF has undergone its first full model change in 17 years, and a new EV model has been added to the lineup. For this EV, Furukawa Automotive Systems developed a converter box ^{(note 2)} in addition to the company’s existing low voltage wire harnesses and high voltage wire harnesses and started mass production and deliveries beginning from July of this year. Also, a high voltage junction box was developed for the ISUZU N-Series EV announced in North America in March of this year, and it is planned to commence mass production from the first half of 2024. When the truck is moving, the newly developed high voltage junction box optimally distributes the electrical power from the battery pack ^{(note 3)} to the inverter ^{(note 4)} and auxiliary equipment such as the heater and air compressor, and it also optimally distributes the electric power from the charger to the battery pack when recharging. In addition, it is equipped with a high voltage fuse for overcurrent protection of the in-vehicle auxiliary equipment, as well as a battery control unit ^{(note 5)} and current sensor that detect the battery state, and an interlock circuit ^{(note 6)} has been set up to prevent electrocution with high voltages. A lineup of four high voltage junction box models that support different numbers of battery packs (3, 5, 7, 9 packs depending on the required driving distance) has been prepared to flexibly respond to the diverse needs of customers.

１: Achieved a smaller design that still considers the heat generated by the use of higher currents

In response to the heat generated by components when powered at high currents, the status of heat generation was visualized through the use of thermal simulations, and the internal components were optimally arranged to satisfy the thermal requirements. Also, for the internal circuitry, a structure that uses a harness for connecting the electrical wires was adopted in addition to the busbar ^{(note 7)}, and the optimum powered state was selected based on our technology accumulated over the years through the development of wire harnesses. As a result, compared to the company’s existing products that generate the same or less heat, the loading ratio of the internal components was improved by 20% (realized smaller size).

2: Prepared a wide lineup that can respond to different battery pack quantities

In order to respond to variation in battery pack setups based on the user’s required driving distance, a lineup of four high voltage junction box models was set. Through the adoption of common components and a different processing method for the metal case, efforts were made to reduce costs by using the same die casting dies for different models, as well as to flexibly respond to customer requirements.

3: Revised the manufacturing method, and contributing to achieving carbon neutrality

The die casting method used to manufacture the metal case has been changed from the traditional melting of aluminum ingots to receiving molten aluminum directly from the smelter. Compared to melting aluminum ingots, this new manufacturing method reduces CO₂ emissions by about 40%.

Furukawa Electric Group will continue to contribute to the promotion of EV and achievement of carbon neutrality in 2050 through product development.