Technical Library

Latest Technology for Quick Charging and Power Supply Systems for EVs


1. Introduction

In order to achieve the full potential of the CO2-free electric vehicle (EV) market, three elements need to be in place: 1) longer driving range, 2) lower cost cars and 3) a readily available charging infrastructure. Two types of charging methods exist today. One is using the on board charger (OBC) located on the car and the other is the quick charger used at charging stations. This press release focuses on the latest technology for quick charging and power supply systems for EV quick chargers, a vital component of the EV charging infrastructure.


2. EV quick chargers and metering systems

Ultra-compact charger for EVs

Ultra-compact charger for EVs


1) Quick chargers for EVs
Towards its goal of realizing a low-carbon society, Japan was the first country to develop EVs and install an EV charging infrastructure. In addition, an industry group led by Tokyo Electric Power Company has proposed an international standard for quick chargers called CHAdeMO. A number of manufacturers in Japan and other countries are already offering products that use this standard, and over 1,617* CHAdeMO-compatible quick chargers have been installed worldwide.

Nichicon is a developer and manufacturer of on board chargers, the devices that charge the lithium-ion batteries found inside EVs. Most of today's mass-produced EVs are equipped with Nichicon OBCs.
Nichicon is also contributing to the spread of a charging infrastructure at vehicle dealerships, local community airports, and highway service areas: it has applied its technology to a four-product lineup (50kW, 30kW, 20kW, 10kW) of the world's smallest and lightest ultra-compact quick chargers for EVs.

Nichicon quick chargers are designed to connect wirelessly to charging infrastructure networks through a communication module. This enables implementation of a metering system by allowing authentication of the user, confirmation of their usage history and other identifying measures.

2) Low voltage quick charging system for EVs combining solar power and energy storage
50kW-class quick charging systems often require high-voltage electrical current, but Nichicon has developed a quick-charging system that can run on a low-voltage power source. This system has been installed at the Suita Service Area on the Meishin Expressway. This rapid charging system combines solar power and a lithium-ion storage battery. It enables a quick charger to operate at 50kW low-voltage level by storing the electricity it requires in lithium-ion batteries.

Low voltage solar powered energy-storing rapid charging system for EVs at the Suita Service Area

Low voltage solar powered energy-storing rapid charging system for EVs at the Suita Service Area


3. Metering system

Due to their experimental status, many existing quick charger stations provide power free of charge. Often local governments have requested to installers that their stations be made free to all EV drivers. However, there are moves to start metering at stations. In its EV pilot project Okinawa charges users 500 yen for a single recharge, and the Tomei Expressway charges for its members-only quick charger service. The Charging Network Development Organization joined with its members to introduce a system for collecting user fees from EV drivers using the FeliCa e-payment card starting from November, and the Japan Charge Network Co. is also planning to start a commercial rapid charging service.

Should commercialization of the rapid charging service for EVs succeed, it promises to expand the charging infrastructure as well as the market for electric vehicles. Another opportunity is the launch of V2H (Vehicle to Home) systems (more below). This should also stimulate demand for EVs among consumers as it demonstrates that there is value in EVs beyond getting from point A to B.


4. EV Power Station for 2-way charging and power supply

In collaboration with Nissan Motor Co., Nichicon has developed a two-way charging and power supply system, the EV Power Station, which allows users to use the large capacity battery in their EV to supply electricity to their home. Since it can power a home using a car battery, it is known as a V2H (vehicle to home) system. The EV Power Station can store inexpensive night-time electricity for daytime use in the home, thus contributing both to peak load reduction and lowering electricity costs.
Features of the EV Power Station:

① Can supply electricity stored in an EV car battery to a home, bringing us closer to the smart house concept of power use.

② Charges an EV in half the time of previous systems.

③Supplies power directly through the home's electricity distribution panel, allowing it to meet all of a family's electricity demand.

④The maximum output of 6kVA is sufficient to run all appliances needed for daily life.

⑤Compliant with the CHAdeMO standard for electrical charging.

⑥Designed to prevent reverse power flow to the grid.

EV Power Station

EV Power Station


5. International standards for quick chargers

Companies in Japan are developing advanced EVs, and are also taking the lead in building the infrastructure necessary for charging the vehicles through the standardization of CHAdeMO, the world's first system for quick charging of EVs. There are currently some 1,300 CHAdeMO-compatible chargers installed around Japan and around 300 overseas, and these chargers are being made by manufacturers in Japan, the U.S., and Europe.

However, late in 2011 a group of eight European and U.S. carmakers introduced a new quick charging system called Combo. The Combo system adopts a connector format that allow both AC charging (level 2) and DC quick charging (level 3), but with different connectors for Europe and the U.S. According to photographs the Combo connector for the U.S. is a charger gun. No details of the Combo system at this stage have been disclosed beyond exterior appearance.

The industry will keep a close watch to see exactly what effect this new system has on car companies and on the market for EVs.

Combo U.S. version Source: SAE International
Combo U.S. version Source: SAE International

6. Conclusion

The first generation of power supply systems is represented by Nichicon advances such as grid-connected solar power generation systems, quick charging systems using storage-battery power generation systems, and the EV Power Station (V2H system) that can provide power to both EVs and households.

The challenge now is to evolve these into "user-friendly products" that reflect the opinions of the people who use them. It is particularly important to link the EV Power Station into the Home Energy Management Systems (HEMS) found in smart homes.

To boost the acceptance of quick chargers and other distributed power generation systems, we have to solve the problems faced by electric power companies and providers of renewable energy and energy storage systems alike - and work towards the realization of a smart grid-based economy.


Nichicon Corporation
From the Dempa Shimbun, Oct. 4, 2012


* Reference: CHAdeMO Association website. (updated September 7 )

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