Technical Library October 6, 2011

Quick Charger Technology for EVs

 
NICHICON CORPORATION
 

1. Introduction

Under its company philosophy of contributing to a bright future society by creating valuable products while protecting the environment, Nichicon is working to solve the serious environmental problem of global warming through the Nichicon Energy Control System Technology (NECST) Project. Inaugurated on March 15, 2010 and under the direct control of President and COO Sachihiko Araki, the NECST project is aimed at achieving a stable supply of energy while still protecting the environment.

Realizing that achieving a stable supply of energy while still protecting the environment has become an even more compelling and pressing task since the Great East Japan Earthquake of March 2011, Nichicon is speeding up its development and introduction of new products. Part of these efforts is Nichicon’s focus on proliferating the use of electric vehicles (EVs). The mass-produced EVs currently available in Japan all use an in-vehicle charger made by Nichicon. We are also contributing to the battery charging infrastructure with facilities for charging EVs and here, we introduce Nichicon chargers and the technology behind them.

 

2. Types of chargers for EVs and Plug-In Hybrid Vehicles (PHVs)

If you want to take a drive in the EVs sold today, you need to recharge your vehicle along the way. With current in-vehicle chargers, it takes about 7 hours for a 200-volt charge. What is needed is a quick charger that can charge in about 30 minutes. (Table 1)

Table 1: Types of EV/PHV charging equipment and charging time

Types of charging equipment Normal charging Quick Charger
Wall socket Normal charging pole
100V 200V 200V
Wall socket 100V Wall socket 200V Normal charging pole 200V Quick Charger
Charging location examples Private Detached homes, apartments, commercial buildings, outdoor parking lots, etc. Apartments, commercial buildings, outdoor parking lots Extremely rare
Public Car dealers, convenience stores, hospitals, commercial facilities, hourly parking lots, etc. Roadside rest stops, gas stations, highway rest stops, car dealers, commercial facilities, etc.
Charging time Driving distance: 160 km Approx. 14 hr Approx. 7 hr Approx. 30 min
Driving distance: 80 km Approx. 8 hr Approx. 4 hr Approx. 15 min
Example cost of charging equipment (excluding installation costs) Several thousand yen Several tens of thousands of yen At least 1 million yen
Sources:
“Guidebook on Installation of Charging Equipment for EVs and PHVs,” published in December 2010 by the Ministry of Economy, Trade, and Industry
Documents of the Ministry of Economy, Trade, and Industry; and the Ministry of Land, Infrastructure, Transport and Tourism
 

3. Workings and Standards of Quick Chargers

Quick chargers are high-capacity power sources that convert alternating current (AC) into direct current (DC) as part of the charging infrastructure. Because these chargers have a high-voltage output of 500 volts, a special connector is required when charging cars. A battery management system (BMS) constantly monitors the state of the in-vehicle lithium-ion battery to ensure safety and reliability, and the quick charger communicates with the BMS during charging. (Figure 1)

A common communication protocol between the BMS and quick charger was developed by the CHAdeMO Association, whose members include entities such as automobile manufacturers, electric utilities, and charger manufacturers. CHAdeMO is the de facto standard for rapid charging of currently mass-produced EVs and EVs that Japanese automobile manufacturers are set to release.
The CHAdeMO Association aims to make this an international standard and is lobbying international standardization groups to this end. Automobile manufacturers in North America and Europe are moving towards adopting the specifications developed by the CHAdeMO Association. In addition, of the quick chargers already installed around the world, many are made by American, European, and Japanese manufacturers that are CHAdeMO Association members.

Figure 1: How a quick charger works (CHAdeMO standard)

Figure 1 How a quick charger works (CHAdeMO standard)

Source: Compiled by Nichicon based on information from the CHAdeMO Association website.
http://www.chademo.com/indexe.html

 

4. Nichicon Ultra-Compact Quick Charger

The greatest benefits of Nichicon’s recently developed ultra-compact quick charger are its installation space (about half of conventional systems) and light weight (about one-third). This lessens foundation construction costs and results in a lower overall burden for customers installing the charger. Another way it contributes to the proliferation of charging infrastructure is through its high reliability and the efficiency of its all-in-one unit construction, made possible with the application of technology that Nichicon has developed with its in-vehicle chargers.

Below are some of the features of this quick charger.
• Can be installed almost anywhere thanks to a compact, lightweight design.
• Employs technology from Nichicon’s in-vehicle charger for high reliability and high efficiency.
• All-in-one construction makes maintenance easy.
• Simple to use thanks to a large LCD panel and intuitive operation.

Figure 2 Ultra-compact quickcharger
Figure 2: Ultra-compact quick charger
 

5. Using a Charger

Using a charger for EVs and PHVs is incredibly easy, and safe as well. Just insert the DC connector into the car’s inlet and press the button on the charger to start charging. As shown in figure 3, it is similar to filling up a car with gasoline. Most chargers use a mechanism that locks the DC connector and inlet together, so the user only needs to make sure this locking mechanism is engaged before starting charging.

Figure 3 Insertion of the DC connector into the vehicle
Figure 3: Insertion of the DC connector into the vehicle

The LCD panel on the charger informs the user when charging is finished, so he or she simply follows the on-screen instructions to remove the DC connector and complete the charging process. If the user does not have enough time to wait for a full charge, the charging process can be stopped at anytime.

 

6. Conclusion

The recent Great East Japan Earthquake may very well prompt more companies and individuals to adopt EVs or PHVs for transportation purposes. EVs, which provide a CO2-free ride, are becoming increasingly familiar to the average citizen: the development of compact, light, in-vehicle chargers made possible by advancements in small, high-capacity batteries and power electronics means that EVs can now be charged in the average home. For the infrastructure of chargers along public roads, Japan’s CHAdeMO system is beginning to see use around the world. Nichicon used the technology built up through its in-vehicle chargers to develop an ultra-compact charger that requires just half the installation space of conventional systems and that reduces installation costs. Nichicon believes this will contribute to the spread of EVs and their supporting infrastructure, and eventually help speed up the realization of a low-carbon society where citizens can enjoy greater peace of mind.

 

Katsuhiko Furuya
NECST Project, Nichicon Corporation
From the Dempa Shimbun, Oct. 6, 2011

 
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