KARIYA, JAPAN, October 10, 2025 - (JCN Newswire) - DENSO CORPORATION (hereinafter “DENSO”) today announced that it has developed new electrification products that contribute to improved energy efficiency, driving performance, and reduced charging time for electric vehicles. These innovations aim to enhance the overall practicality of electric vehicles. The newly developed products comprise an Inverter that will be installed in the new eAxle from BluE Nexus Corporation, along with a Cell Supervising Circuit designed to measure battery voltage and temperature, and a Shunt Current Sensor for measuring current. These products will be installed in the new TOYOTA “bZ4X”.

Key New Products for the TOYOTA bZ4X

- Inverter

The inverter, a core component of BEV*1 and PHEV*2, plays a critical role in converting DC power from the battery into AC power to drive the motor. To meet demands for extended driving range, enhanced performance, and flexible installation to preserve cabin space, inverters are required to be compact while minimizing power loss and heat generation and supporting high current output.

To address these challenges, DENSO has developed a new flat dual-sided cooling inverter structure, leveraging its proprietary dual-sided cooling technology, cooling design, and power semiconductor expertise. By evolving key technologies such as SiC (silicon carbide) power semiconductors, surrounding circuitry, structural design, high-efficiency cooling, and integrating them optimally, DENSO has achieved world-leading power density*3 (output(kW) per unit volume(L)). Compared to DENSO’s previous Si-based products, the new inverter reduces power loss by approximately 70%. Its core module, composed mainly of semiconductors and cooling channels, has been downsized by about 30%.These contribute to improved driving range and performance for BEVs.

Key Development Highlights of Inverter

SiC Power Semiconductor

Developed using DENSO’s proprietary 3D structure technology, achieving the world’s lowest on-resistance*4 for reduced inverter losses.

Drive Technology to Maximize Device Performance

Through innovations in resin-insulated substrates and current pathways, we achieved approximately 50% reduction in inductance*5 compared to our conventional products. This allows for high-speed switching that fully leverages the performance of the power semiconductor.

Advanced Cooling Technology

Leveraging thermal management technologies cultivated through car air conditioning and engine cooling, we optimized the heat dissipation structure using elliptical pin fins, achieving approximately 40% better cooling performance compared to market trends. Furthermore, DENSO’s proprietary double-sided cooling technology enables flat placement of power cards, successfully balancing miniaturization of the Core Module—a key component—and support for high current.

Optimization Through Integrated Technologies

By optimally combining the above elemental technologies—including flow balance in double-sided cooling and device layout tailored to cooling performance—we maximized the benefits of low power loss and high cooling efficiency, achieving the world’s highest power density.

- Battery Management Products

In BEVs and PHEVs, precise monitoring of battery voltage and current is essential for safe, stable, and long-lasting battery operation. As the number of battery cells increases to meet range demands, efficient monitoring technologies that maintain accuracy while controlling costs are increasingly important.

DENSO has developed a new Cell Supervising Circuit and Shunt Current Sensor through the creation of new ICs using proprietary semiconductor technology and the development of technologies to further improve detection accuracy based on detailed verification of material properties. These innovations enable more accurate measurement of battery and current conditions with fewer monitoring circuits, helping reduce costs and contributing to shorter charging times for BEVs.

Key Development Highlights of Cell Supervising Circuit 

28-Channel Cell Voltage Monitoring IC

Utilizing DENSO’s proprietary high-voltage semiconductor process, we have developed the world’s first 28-channel cell voltage monitoring IC. This innovation enables highly accurate battery monitoring while reducing the number of cell monitoring circuits by 20% compared to conventional technologies.

Circuit-Level Optimization

By applying noise stress quantification technologies for circuits surrounding the monitoring IC, along with DENSO’s expertise in optimizing monitoring IC and PCB design, we successfully reduced the number of components required for overvoltage and noise countermeasures. This approach enables both safe battery usage and extended battery life, while also achieving cost reduction.

Key Development Highlights of Shunt Current Sensor 

Shunt Resistor*6

By adopting a shunt resistor method for current monitoring, we achieved highly accurate current detection.

Correction Technology

Due to variations in resistance values caused by ambient temperature and individual differences—such as those arising from welding with copper—correction is necessary for shunt resistors. To address this, we conducted a material characteristic evaluation of shunt resistors and clarified the temperature range in which such variations occur. Furthermore, by applying DENSO’s proprietary correction technologies and expertise, we developed a new correction logic that achieves the same level of precision as multi-point correction using only minimal temperature data. These efforts have halved the detection error compared to conventional products while keeping costs low, contributing to shorter charging times for BEVs.

DENSO will continue to advance elemental technologies across a wide range of fields and integrate them to create high-value electrification products. Through these efforts, DENSO aims to improve EV practicality, accelerate adoption, and contribute to the realization of a carbon-neutral society.

*1 BEV: Battery Electric Vehicle – powered solely by electricity, without using gasoline
*2 PHEV: Plug-in Hybrid Electric Vehicle – capable of short-distance travel using electricity only, similar to BEV, without using gasoline
*3 World-leading power density: based on a comparison of identical specifications (as of January 2025, according to internal research)
*4 On-resistance: Internal resistance that occurs when a transistor is in the “on” state. In switching elements such as MOSFETs, lower on-resistance indicates less power loss and enables more efficient power conversion.
*5 Inductance: A property of components like coils, where changes in current induce a voltage. Lower inductance improves circuit efficiency and responsiveness, and helps reduce switching losses.
*6 Shunt resistor: A resistor used for measuring electric current, primarily utilized in current detection circuits. When current flows through the shunt resistor, a small voltage is generated, and by measuring this voltage, the current can be detected with high precision. Since it also serves as part of the vehicle’s system current path (made of copper), it includes a welded joint with copper.

Inverter

Core Module (a key component of Inverter)

Cell Supervising Circuit

Shunt Current Sensor

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