Hybrid electric vehicles electrochemical capacitors

Electrochemical capacitors have been studied for many years. The first patents date back to 1957, where a capacitor based on high surface area carbon was described by Becker. Later in 1969 first attempts to market such devices were undertaken by Standard Oil Company of Ohio (SOHIO). However, only in the 1990s did electrochemical capacitors become famous in the context of hybrid electric vehicles. The electrochemical capacitor (EC) was supposed to boost the battery or the fuel cell in the hybrid electric vehicle to provide the necessaiy power for acceleration, and additionally allow for recuperation of brake energy (Viswanathan, 2006). 

Stewart, S. G., Srinivasan, V., and Newman, J. (2008). Modeling the performance of lithium-ion batteries and capacitors during hybrid-electric-vehicle operation./ Electrochem Soc., 155(9) pp. A664-A671. 

Electrochemical power sources, rechargeable batteries and supercapacitors (or electrical double-layer capacitor, EDLC), are attractive in the wide range of applications, such as mobile electrical devices, hybrid electric vehicle (HEV), and smart grid. In the past century, considerable research efforts have been done to study the... 

Electrochemical double-layer capacitors with activated carbon electrodes are commercially available from several companies. In the case of hybrid capacitors, lithium-ion capacitors which consist of the anode of a lithium-ion battery and a cathode of activated carbon are commercially available, as mentioned above. These super capacitors show great promise as next generation power sources for electric devices and electric vehicles. More innovation is needed before pseudo capacitors are suitable for commercialization. 

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