British Researchers Tout High-Temp Capacitors for EVs

Researchers at the U.K.'s National Physical Laboratory have developed an innovative ceramic capacitor they say can withstand a higher operating temperature and thus hold more power than a conventional device.

Capacitors act like batteries to store and release energy but can do so faster, making them attractive in electric and hybrid vehicles when sudden bursts of power are needed. They're also needed to convert DC battery power to AC current required to power an EV's drive motor.

But EV power electronics require complex and heavy cooling systems to maintain performance of their capacitors as voltage and temperatures rise, thereby adding weight and reducing overall operating efficiency.

The British scientists say the key to their so-called HITECA design is a ceramic construction that can operate stably at more than 200 C, compared with about 125 C for conventional capacitors that use liquid electrolytes or polymers.

The patented device is made from a ceramic paste of bismuth ferrite compound doped with strontium titanate to form a lead-free granular structure.

The NPL research was co-funded by the U.K.'s Technology Strategy Board and National Measurement Office. The lab's partners included Queens University of Belfast, Queen Mary University of London, capacitor firm Syfer Technology, materials processor NanoForce Technology and France's Valeo.

Tatiana Correia, who headed the NPL team, notes that ceramic capacitors also could boost performance in high-temperature electronics in aerospace and industrial applications.