Conductive Charging of Electrified Vehicles(EVs)-Challenges and Opportunities

The growing concern of carbon dioxide emissions, greenhouse effects, and rapid depletion of fossil fuels raises the necessity to produce and adopt new eco-friendly sustainable alternatives to the internal combustion engine (ICE) driven vehicles. For this reason, in the last decade, EVs have become in some way widespread, principally because of their negligible fuel gas emissions and lesser reliance on oil.

Talking of growth, electric vehicles (EVs) have advanced tremendously during the last 20 years, both in terms of advancement of battery technology and reduction of battery costs. Until recently, EVs were typically costlier than gasoline-fueled vehicles. To facilitate the commercial success of EVs, cutting-edge batteries and infrastructure to support battery charging must be developed and installed, which will make EVs more affordable, more accessible, and easier to use. EV charging is kind of spearheading in terms of innovations.

There are basically three ways of charging an EV battery. Charging is done either by conductive or inductive charging and thirdly by replacing the batteries. The EV charging system consists of a charger control unit, charging cable, and vehicle control unit. Chargers can be classified into two main groups, inductive and conductive. The inductive charger has no contacting surface and a magnet is used to transfer the power. Although this coupling brings convenience to drivers, it has not achieved a highly efficient level yet. The conductive charger is a conventional device that induces power through contact.

Electric Vehicle Automated Conductive Charging System

Conductive charging uses direct contact between the EV connector and the charge inlet. The cable can be fed from a standard electrical outlet or charging station. The conductive charger for EVs has the advantages of maturity, simplicity, and low cost because it simply makes use of plugs and sockets to conduct electrical energy via physical metallic contacts. There are two methods employed in EV charging stations using conductive method viz. AC chargers or on-board chargers and DC chargers or off-board chargers.

Conductive power transfer uses a conductor to connect two electronic devices in order to transfer energy. There are three basic components when it comes to charging electric vehicle cables, connectors, and batteries, and on the basis of the same conductive charging is bifurcated into off-board and onboard charging.

Electric Vehicle Conductive DC Charging System

DC charging is carried out off-board using a DC charger. It utilizes dedicated DC EV supply equipment to provide energy from appropriate off-board chargers to EV in public locations. It is known as fast DC charging. There is power level flexibility, unlike onboard chargers. It can be used up to 50KW i.e. battery can be charged in 20 minutes from empty to 80% full. But sometimes this number varies depending on the battery condition and the quality of the vehicle.

The chargers which are used till now for connecting the vehicle to the external power station are:

1. CCS US
2. CCS Europe
3. Chademo
4. Tesla US/Eu
5. China GB/ T Standard

All of these have different numbers of pins, phases, and voltage power and are used according to the power input in the vehicle. Despite being the fastest mode and having no limitation on the power supply, the DC charging system still has few limitations.

The limitations are listed below:-

• Higher losses in charger and Battery
• Battery:- Shorter battery life, only 70-80% SOC can be charged with fast charging
• Cable: Limited maximum current for cable that can be easily lifted
• High investment
• Adverse impact on grid
• Available only at public charging stations
• Thermal management

Electric Vehicle Conductive AC Charging System

AC charging is what most common power outlets use for their charge process. To charge, the vehicle simply has to be connected to an ordinary electric socket or a higher power outlet specifically designed for EVs. As you can see, the space and materials needed for this type of charging station are quite small. However, charging takes longer and for this process, the car has to be equipped with an onboard charging unit, which adds to the car’s weight. Onboard chargers have this exception that they are limited with power supply. Though power flexibility is the main motto of charging an electric vehicle.

The whole process of charging in an AC charging system is a bit different. There are Proximity pilots (which keep checking for the establishment of the connection between the EV and Infrastructure Plug), Control pilots (Controls the maximum current that can be drawn) as the charging input are installed within the vehicle. So, keeping a check on maximum current supplied becomes a must in such situations. The three main types of equipment used are vehicle net, charging cable, and infrastructure plug.

The types of chargers used in an AC charging system are

1. US/Japan SAE
2. Europe Mannekes/ Tesla
3. EV Plug Alliance
4. Tesla US

AC charging system has the major benefit that you can charge anywhere with the standard electrical outlet and it has Battery Monitoring System (BMS) with easy communication. Though it comes up with some major drawbacks like power output, relatively longer charging time, and more vehicle weight due to the installed input unit.

Wireless Charging of Electric Vehicles(EVs)

In a world where charging electric cars is a key point in boosting the energy transition, other solutions can come alongside electric charging stations. One such solution is wireless charging. Wireless car charging is an enhanced version of smartphone charging with several differences. “Wireless inductive charging allows an electric vehicle to automatically charge without the need of cables.

It is proven over the ages, everything is scalable technically; however, as power transfer rates go up, the complexity and size of the power management electronics must go up. More importantly, as the power goes up, a number of additional factors need to be considered, such as thermal losses and thermal management. The higher the inefficiency, and the higher the power, the higher the heat losses and more that must be done to manage that heat.

Inductive Charging uses an electromagnetic (EM) field to transfer energy between two coils. Magnetic resonance is created between the coil of the charging station and the coil of the vehicle grid. The coils are tuned in to the same frequency and energy transfer takes place between them. It is as simple as the energy is transferred from a mother to a kid sitting on a swing.  Energy is transmitted through an inductive coupling to the electrical devices. This energy is used to charge batteries. Inductive chargers are used with an induction coil to create an alternating EM field from the charging base. A portable device such as cars or trucks uses a second induction coil to receive the EM field. These EM fields are converted back into electric current in order to charge the battery of the EVs.

Managing all the additional factors and technical challenges, we have inductive charging that made charging as easy as just parking your vehicle. The interesting fact is that wireless charging is 93% efficient which is almost end-to-end if compared with traditional refueling methods. Everything comes up with some bane and boon, people are accepting of this technology but at the same time fear of mishappenings. But experts have discussed the security of wireless charging and they are very confident that it is as simple as cooking in the kitchen. In the kitchen too, we have to keep in mind some safety measures and similar is the case with wireless charging.

Even big brands of automotive like BMW are trusting in this technology. In 2018, BMW launched their new model with wireless charging and quoted that “BMW makes charging easier than refueling.

Dynamic Electric Vehicle Charging: All that we talked about till now is all about static wireless charging. The new next-best-thing that EV innovators are working on is Dynamic Electric Vehicle Charging (DEVC), which allows an EV to charge wirelessly as it’s driving down the road. The system is capable of charging an EV dynamically at up to 20 kW at highway speeds (100 km/h).

Challenges and opportunities

Right now, EVs is all about challenges in terms of infrastructure, vehicle cost, charging time, types of equipment, etc. Innovator believes that the innovation of EV will be the best innovation for cutting carbon emissions and clearing the way for significant climate progress.

Listed below are the few challenges that are coming with the present infrastructure-

Charging Time: There are three major “levels” of chargers available for EVs. The standard 120-volt plug, often used for home appliances, charges slowly but can fill a battery to near full capacity with several nights’ charge, or about 20 to 40 hours. The 240-volt “level two” chargers generally provide 20 to 25 miles of charge in an hour, which shortens charging time to eight hours or less. Finally, “level 3” direct current (DC) fast chargers can charge a battery up to 80 percent in 30 minutes. Currently, level two chargers are the most widely available—the Department of Energy lists 22,816 public stations in the United States.

Availability of charging infrastructure: Rather than being refueled at a typical gas station, electric vehicles(EVs) must be charged at electrical outlets in order to run. Many EV owners charge their cars at home in their garage using a special wall-mounted charger. This arrangement works for most people because the average person drives 29 miles per day. This distance is well within the range of today’s electric vehicles, most of which can travel between 150 and 250 miles on a charge, depending on the model. However, two major difficulties arise. First, for drivers who live in apartments, parking garages are rarely equipped with charging infrastructure, and installing such infrastructure may be cost-prohibitive for building managers.

Pricing: Unlike gas stations, where the price of fuel is set per gallon, EV charging can currently follow a number of different pricing schemes, which can lead to inconsistent pricing and sometimes high charging costs. Home charging prices are consistent rates per kilowatt-hour (kWh) set by utility regulators. Public charging station pricing has used schemes including per-session fees, per-minute fees, and tiered pricing based on a vehicle’s max charging speed. Charging fees are often not displayed at charging stations. This inconsistency and lack of transparency are barriers to EV adoption because they can lead to frustration and negative customer experiences.

Opportunities

• Manufacturing Opportunity: Multiple narratives have come up while talking of opportunities; even top companies of India like NTPC, Bharat Heavy Electricals Ltd (Bhel), and Power Grid Corp. of India Ltd all wanted to be a part of this pie. Everyone can see this is going to be the future of the Automotive Industry. The rising of the EV industry is obviously providing a lot of opportunities to the manufacturing industry. Even big e-commerce giants like Flipkart or Amazon are also shifting their existing vehicle fleets to electric. Jeff Bezos-led Amazon said it will introduce 10,000 units of electric vehicles in its goods delivery fleet in India by 2025. Walmart-owned Flipkart plans to introduce 25,000 units of electric vehicles in its fleet to cut down on vehicular emission. All this will definitely be creating an immense pool of manufacturing opportunity to meet this huge demand.
• A huge surge in B2B opportunities: Not only businesses but consumers are showing increasing interest in electric mobility, the growing media attention even globally has made a wide space for ample opportunities in the business-to-business market. Major Key players are already creating a stir in manufacturing utilities for sustained thrive of the EV sector. In a conference event in Berlin, the CEO of Volkswagen Matthias Muller announced that they had secured battery supply partners in Europe and China.
• Battery Technology: Battery Technology is an integral part of the Electric Vehicle ecosystem in India. The technologies in the electric vehicle battery market have undergone significant changes in recent years, with battery technology evolving from low energy density to high energy density. A lot of market research has indicated that electric vehicle battery technology is forecast to grow at 38% CAGR from 2020 to 2025 which creates ample space for business opportunities in Battery Technology. To push the market further, the Government of India established the National Mission on Transformative Mobility and Battery Storage under the Chairmanship of Niti Aayog. With a significant emphasis on localization, measures are being taken to reduce dependence on import and manufacture batteries and other components indigenously.
• ICE Scrapping: With more and more interest in Electric Mobility, it is but obvious that dwindling interest in ICE would be an automatic casualty. And as the Internal Combustion Engine Vehicles become obsolete, the business opportunities for scrapping them will grow more in the future. A lot of these pollutant vehicles will be barred on the road and will end up in scrapping centers, metals, and materials of which will be recycled to make and innovate environmentally aligned products.

Sheeba Chauhan | Sub Editor | ELE Times