Technical Library

Charging Systems for EVs
Latest Trends and Efforts Towards Proliferation

NICHICON CORPORATION

1. Introduction

The new Japanese government that took power at the end of 2012 announced a long-term strategy made up of a three-pronged approach: bold monetary policy, flexible fiscal policy, and a growth strategy that encourages private sector investment. Based on this approach, the government approved a fiscal 2012 supplementary budget of ¥100.5 billion for a project to promote development of charging infrastructure for next-generation vehicles such as EVs (electric vehicles) and PHVs (plug-in hybrid vehicles).
Long anticipating such projects and policies, Nichicon Corporation has for some time now been developing EV-related equipment and quick chargers for the EV infrastructure. Many of the mass-produced EVs currently sold in Japan use Nichicon-made OBCs (on board chargers). The experience and technology gained from these OBCs went into the development of EV quick chargers, and Nichicon has amassed a lineup of revolutionary ultra-compact quick chargers for EVs. Let’s look at the aforementioned subsidization project, the EV quick chargers it will cover, and the latest trends and technologies in EV-related systems.

2. Project to Promote Development of Charging Infrastructure for Next-Generation Vehicles

Under its fiscal 2012 supplementary budget, Japan’s national government approved a project to promote development of charging infrastructure for next-generation vehicles. The goal is to speed up proliferation of the charging infrastructure necessary for EVs and PHVs, thus stimulating capital investment and hastening the growth of the next-generation vehicles, in the process shoring up the Japanese economy. Below are four ways the project will partially subsidize the purchase and installation of chargers:

(1)
A subsidy will cover two-thirds of the cost of purchasing and installing EV chargers that are installed for public use and in line with local governments’ visions for implementation of national government policies.
(2)
A subsidy will cover one-half of the cost of purchasing and installing EV chargers that are installed for public use but not in line with local governments’ visions for implementation of national government policies.
(3)
A subsidy will cover one-half of the cost of purchasing and installing EV chargers that are installed in apartment parking lots and privately run monthly-rate parking lots.
(4)
For cases other than those in (1), (2), and (3), a subsidy will cover one-half of the cost of EV chargers (as was the case previously).

The majority of local governments around Japan are drawing up their proposals, and once these are announced, the process for deciding on locations and choosing installation contractors will begin.

3. Workings and Standards of Quick Chargers

Quick chargers are large-capacity power sources with double-digit kilowatt capacities that convert AC (alternating current) into DC (direct current). Because the quick chargers have a high-voltage output of 500 volts, a special connector is required to safely supply the cars’ lithium-ion battery with a large current of electricity. A battery management system (BMS) constantly monitors the state of the on-board lithium-ion battery to ensure safety and reliability. The quick charger communicates with the BMS for safe charging of the vehicle.
The communication protocol between the BMS and the quick charger is called CHAdeMO, a quick charging scheme 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 quick charging the EVs that Japanese automobile manufacturers are currently mass-producing and will mass-produce in future.
The CHAdeMO Association aims to make this an international standard and is lobbying international standardization groups to this end. In the U.S. and Europe, there are already several companies coming out with quick chargers using specifications developed by the CHAdeMO Association. But while there are an increasing number of quick chargers worldwide based on the CHAdeMO standard, there is a new quick-charging system, called Combo (Combined Charging System) and using a newly shaped charging connector, introduced by a group of eight European and U.S. automobile companies.
In Japan, manufacturers have been central to developing advanced EVs, promoting the standardization of CHAdeMO, (the first EV quick-charging standard in the world), and taking the leading role in establishing EV charging infrastructure. Companies in Japan will continue to accelerate the proliferation of CHAdeMO quick chargers with the goal of making this the world standard for quick chargers.

4. Ultra-Compact Quick Chargers for EVs

With its goal of realizing a low-carbon society, Japan was the first country to mass-produce EVs and install EV charging infrastructure. A number of manufacturers in Japan and other countries are already offering quick chargers using the CHAdeMO standard, and to date over 2,400 CHAdeMO-compatible quick chargers have been installed worldwide. Nichicon was the first company in the world to develop and manufacture OBCs, the devices that charge the lithium-ion batteries found inside EVs. Nichicon products such as an OBC with DC/DC converter (photo 1) and quick chargers are used in many of the EVs mass-produced today.
Nichicon has applied its OBC technology to develop the world’s smallest series of ultra-compact quick chargers for EVs (photo 2). Its lineup of four products, in outputs of 10, 20, 30, and 50kW, is contributing to the proliferation of EV charging infrastructure.

Photo 1: OBC with DC/DC converter

Photo 1: OBC with DC/DC converter

  Photo 2: Ultra-compact quick charger for EVs

Photo 2: Ultra-compact
quick charger for EVs

5. Using Quick Chargers

Using the quick 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 quick charger to start charging. As shown in photo 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 needs only make sure this locking mechanism is engaged before starting charging.

Photo 3: Insertion of the DC connector into the vehicle

Photo 3: Insertion of the DC connector into the vehicle

When charging is finished, the EV informs the charger to stop. The chargerís panel notifies the user that charging is complete and shows how to disconnect the DC connector from the vehicle to complete the charging process. If the user does not have enough time to wait for a full charge, the charging process can be stopped anytime.

6. Related Systems (Distributed Power Source and Quick Charger)

Nichicon has developed a system for a public relations facility (called the ‘Solar power facility in Yamanashi Prefecture Public Relations’) in Yamanashi Prefecture, Japan (photo 4 and 5), which combines solar and stored power to provide all the facility’s electricity, as well as electricity for charging EVs. This system is a distributed power source that gathers energy from multiple sources such as hydropower and fuel cells and stores it to be used in numerous ways. Displayed and operating in the aforementioned public relations facility, the system has a 20-kW solar panel and a 15-kW hydropower source for input; a 32-kWh lithium-ion battery and a 3MJ EDLC for storage; and output capacity in the form of a 30-kW quick charger. It has an outdoor DC connector for quick charging of EVs. The system stores the power generated by renewable energy after converting the voltage level with a DC/DC converter, converts it to AC, and supplies power to the building’s load while providing direct current from the battery to the quick charger, thus raising overall efficiency and achieving energy savings. Because this system stores renewable energy, it can operate independently, making it an emergency power source in the event of disasters, and as an emergency quick charger. This makes it a promising part of Japan’s infrastructure,  a country often beset by natural disasters and currently suffering from an energy shortage.

Photo 4: Komekurayama Mega-solar Power Plant in Yamanashi Prefecture

Photo 4: Komekurayama Mega-solar Power Plant in Yamanashi Prefecture

Photo 5: Distributed power source

Photo 5: Distributed power source

7. 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 the large capacity battery in an EV to be used 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 (photo 6). 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. This is a revolutionary step in product added-value: in addition to EV benefits such as quiet operation and excellent acceleration, users now get a stable supply of electricity through peak-time shifts and peace of mind knowing they have a source of power in times of emergency.

Features of the EV Power Station

(1)
Stores electricity at night for use in the daytime to contribute to peak-time shifts and lower electricity costs.
(2)
The lithium-ion battery in the Nissan Leaf EV can be used as a backup power source.
(3)
Can fully charge the battery in as little as four hours, which is about twice as fast as a conventional 200V household power source.
(4)
Compliant with the CHAdeMO standard for electrical charging and discharging.
(5)
Peace of mind for users knowing there is stable power source in case of an emergency.
(6)
Access to electricity even when not connected to the power grid.

Photo 6: EV Power Station

Photo 6: EV Power Station

8. Conclusion

The EV is often called the car of the future, and the number of EVs on the road is still far less than that of gasoline vehicles due to economic problems  and travel distance between charges. However, recent advances in compact, high-capacity batteries and power electronics have made possible the development of ever-smaller and lighter OBCs, and EVs can now be charged in the average home. The day when EVs become a familiar sight on the road is not far off. And thanks to government-led efforts, we are on the verge of a dramatic increase the number of publically installed EV chargers, a device key to the proliferation of EVs. Ultra-compact quick chargers, developed by Nichicon using technology built up through OBCs, occupy approximately 50% less space and weigh only about one-third as much as previous Nichicon chargers, thus saving the customer cost and effort in installation. Nichicon has also brought a new value proposition to the market by mass-producing for the first time in the world the EV Power Station two-way charging and power supply system. These efforts are expected to contribute to the proliferation of EVs and EV charging infrastructure in line with local government policy, and play a role in bringing us closer to a world of stable electricity and lower carbon emissions.

 

NICHICON CORPORATION
From the Dempa Shimbun, Apr. 11, 2013

 
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