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Latest Technologies for Quick Charging and Power Supply Systems for EVs


1. Introduction

To realize a low-carbon society and thus curb global warming, countries are developing new energy sources to replace fossil fuels. In Japan, the Great East Japan Earthquake of March 2011 has prompted a major energy policy turnaround: from the conventional strategy of using nuclear power, a non-fossil-fuel energy source, to far greater use of renewable energy sources like solar power.

This summer there are expected to be energy shortages in West Japan and other regions of the country, and these will likely be met with rolling blackouts such as the kind initiated in the Tokyo area last year.

While there will be a change to a greater proportional use of renewable energy, what won’t change is the need for a stable supply of electricity for improving people’s lives and advancing economic development.

For the time being, society has no choice but to manage its energy use efficiently by saving, generating, and storing the limited electricity available to it. One proposal for effective energy management is to make use of storage-capable lithium-ion batteries to store plentiful night-time electricity and use it for peak-time shifts in the daytime.


2. Quick Charging and Power Supply System for EVs

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 (electric vehicles) 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 1,200 CHAdeMO-compatible quick chargers have been installed worldwide.

Nichicon is a developer and manufacturer of OBCs (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 charging infrastructure: it has applied its technology to a four-product lineup (10-, 20-, 30-, and 50kW) of the world’s smallest and lightest quick chargers for EVs.

2) Quick Charging System Combining Solar Power and Energy Storage
50-kW-class quick charging systems often require high-voltage electrical equipment, but Nichicon has developed a quick-charging system that can run on a low-voltage commercial power source. This system has been installed at the Suita Service Area on the Meishin Expressway in West Japan. This quick charging system combines solar power and a lithium-ion storage battery, so it has the advantage of being able to operate on its own as an emergency power source.

Energy-conserving/energy-storing rapid charging system for EVs at the Suita Service Area on the Meishin Expressway
Energy-conserving/energy-storing rapid charging system for EVs at the Suita Service Area on the Meishin Expressway

3. EV Power Station for 2-Way Charging and Power Supply

Nichicon has developed a two-way charging and power supply system, the EV Power Station, which allows users to not only charge their EVs but also to use the large capacity battery in an EV to send electricity to a 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 and shift it to the daytime for use in the home, thus contributing both to peak-time shifts and lower electricity costs.

Feature of the EV Power Station
Can send electricity stored in an EV car battery into a home; this brings society closer to the realization of the smart house concept.
Charges an EV in approximately half the time of previous systems.
Stores electricity at night for use in the daytime to contribute to peak-time shifts and lower electricity costs.
Supplies power directly through the home’s electricity distribution panel, allowing it to meet all of a family’s electricity demand.
The maximum output of 6 kW is sufficient to run all appliances needed for daily life.
The electricity stored in a 24-kWh lithium-ion car battery, like that in the Nissan Leaf, for example, is enough to supply the power needs of an average Japan household for two days.
Compliant with the CHAdeMO standard for electrical charging and discharging.
Designed to prevent reverse power flow to the grid.
EV Power Station
EV Power Station

4. Standardization of 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 EV quick chargers.

There are, so far, more than 1,200 CHAdeMO-compatible chargers installed around the world, and these chargers are being made by manufacturers in Japan, the U.S., and Europe. This year, a group of eight automobile companies in the U.S. and Europe introduced a new fast-charging system called Combo. The industry will keep a close watch to see exactly what effect this new system has on car companies and on the proliferation of EVs.


5. Connection with Household Power Storage Systems

There is a complementary relationship between fixed power storage systems and mobile storage systems, the latter referring to the V2H system using EV storage-capable batteries. Assuming that the EV is parked outside the home, there must be a way for customers to automatically choose the most economical energy method by making optimal use of the fixed storage system. It is up to private companies to explore ways to make the most effective use of things like HEMS (home energy management systems).


6. Conclusion

The first generation of power supply systems is represented by distributed systems: these include grid-connected solar power generation systems, storage-battery power generation systems, and fuel cells.

To proliferate such distributed power systems, we have to solve the problems faced by all concerned parties—utilities companies, providers of renewable energy and energy storage systems—and work towards the realization of a society in which power is supplied by smart grids.


Nichicon Corporation
From the Dempa Shimbun, July 2, 2012

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