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CHARGING INFRASTRUCTURE OF EV

CHARGING PROTOCOL AND PLUG HARMONISATION

Currently, car makers in Europe, China, Japan and Tesla in the USA, use two communication protocols and four different connectors to link chargers to batteries, but companies constructing the charging networks necessary for electric vehicles to become mainstream, say the number of plug formats will need to be limited and even consolidated to one main protocol to keep future costs low.

Rapid Charger Connector Variants

It is widely thought that over time CCS and CHAdeMO will converge, most likely into the current CCS protocol, Tesla looks to be moving this direction too, with all European Model 3’s fitted with CCS connectors. The main benefit of CCS over its competition is that it is a dual mode plug, capable of using Type 2 AC charge connectors, as well as the CCS combined AC and DC plug. Figure 14 highlights the stark differences between the 4 global rapid charge formats.

At the moment, Tesla Supercharger, CHAdeMO and CCS plugs continue to be installed in Europe as well as the United States and China appears to be powering ahead with GB/T, implying that it is too early to declare the victor in this war of plugs.

CHARGING STATIONS

Pure battery EVs (BEVs) are most commonly charged from the electricity grid overnight at the owner’s residence, so long as they have their own charging box or adaptor to plug directly into the mains sockets. Power from the grid is generated from a mixture of sources. The main generators use nuclear power (arguably green power), coal, and gas. Although renewable power is becoming more common in most countries, including hydro, wind and solar power. Complete reliance on renewable power is becoming the ultimate goal for most governments due to concerns regarding carbon emissions, pollution and global warming. Total renewable power would need to use recent emerging technology of large-scale BESS (Battery Energy Storage Systems) to store the energy when demand is low and release the energy when demand is high. There are already many of these innovative systems operating globally.

There are many variations of public charging stations that provide differing speeds of charging, with slow charging common for private households to more powerful charging stations sited on public roads and highways. As an example of how different chargers perform, the BMW i3 can charge 0–80% of the battery in around 30 minutes in DC rapid charging mode, whereas on a home charger, the charge time rises to about 8 hours. In contrast, the Tesla superchargers can supply up to 150 kW of charging, allowing a 300-mile charge in just under an hour. As battery technology advances, new models such as the Porsche Taycan uses 1000V batteries and will soon be able to accept charge at twice the Tesla rate.

CHARGING POINT TYPES AND CONNECTORS

Type 1

The Type 1 plug is a single-phase plug that allows charging power levels of up to 7.4 kW (230V, 32 A). This protocol is mainly used in EVs and is rare in Europe, being mainly confined to the Asian region.

Type 1 Connector

Type 2

Although infrastructure for EV public charging points is expanding, they are still not common outside urban conurbations. Type two, affectionately known as slow to fast chargers, far outweigh any other type of charger in most countries The IEC 62196 Type 2 connector is used for charging electric cars predominantly in Europe. The connector is circular in shape, with a flattened top edge and originally specified for charging battery electric vehicles at between 3–50kW AC.

Type 2 Connector

Type 3

Finally, there is the growing expansion of Type 3 rapid or ultra-chargers that use DC power. Type 3 chargers can provide a full charge in 30 to 50 minutes and are often found on the main arterial routes and highways across countries, to facilitate long distance EV motoring. The very latest Type 3 chargers can charge in less than 30 minutes, with a planned 10-minute recharge in the not too distant future. They typically charge at rates from between 50kW to 150kW DC.

CCS is the European charging connector standard that combines Type 2 fast charging with DC rapid charging in one connector.

Fact

CONDUCTIVE COUPLING

Conductive coupling is where a plug and a socket physically lock together for transfer of power, is used to supply electricity for recharging most electric vehicles. Although there is now a battle between manufacturers on what connector is standard, much the same as VHS versus Betamax during the 70’s. In Europe and the USA, the CCS (Combined Charging System) is the preferred plug amongst manufacturers, with the exception of Tesla. Although European Tesla Model 3’s come with CCS connectors now. Japanese manufacturers opted to use the CHAdeMO system, a connector completely different in form and function to the CCS European standard. The main differences are that CCS is a dual mode plug that incorporates the Type 2 plug and DC rapid charger plug combined, whereas the Japanese must use adaptors or two sockets to perform the same functionality. Figure 14. highlights the difference in charging protocols. Nevertheless, CCS seems to be gaining momentum as the connector of choice due to its dual mode flexibility.

INDUCTIVE CHARGING

Another approach is inductive charging, using an inductive plate inserted into a slot in the car or one that comes in close contact with the inductive receptor. This technology is not new for low current applications. You probably use this type of charging regularly at home, either with your toothbrush or mobile phone.  

There are two main types of conductive charging options: Static and mobile. Static conductive charging occurs when you are parked up, perhaps in a parking bay. Once activated in park mode, the car draws charge much the same as a toothbrush or mobile phone, from a transmitter plate in the road and receptor plate on your car. This method of charging is not as efficient as conductive charging, but the positive feature of this method is that there are no cables that can be damaged or vandalised, so it is ideal to install on a public road. Figure 14 highlights the concept of mobile inductive charging – on the go. An EV would effectively collect power on the move, from inductive rails or coils, embedded just below the roads surface.

Mobile Inductive Charging

VEHICLE TO GRID: UPLOADING AND GRID BUFFERING

There are a number of countries where EV owners are now contributing to support the electricity grid during peak load periods when the generation cost can be very high. In this situation, EVs can contribute energy to the grid and in most cases get paid for their contribution. The owner’s vehicles can then be recharged in off-peak hours, typically overnight, or by a renewable energy source such as solar panels at lower rates, whilst absorbing excess night time electricity generation. In this situation, the cars batteries act as a distributed energy storage system to cushion power demand. Portugal’s island of Porto Santo in the Atlantic Ocean now has a growing scheme in place to assist in effectively minimising pollution generated by its diesel generating plant, by buffering and feeding back energy required during peak times of the day from their EV.

CHARGING INFRASTRUCTURE

EVs have long faced two significant issues, lack of places to charge and limited range. With each new model launch and battery technology breakthrough, electric car ranges are increasing too. Although is the charging infrastructure there to support the increase in new EVs to support the forecast upsurge in electric car use and will the current charging infrastructure support your lifestyle with the charging network in place now? This section will hopefully address these important questions and more.

The majority of EV users plug in at work and home. Most EV users park their cars for hours on end either outside offices, factories or houses. This situation is the perfect opportunity to charge your EV battery, so the car is fully charged whenever and wherever you need it. A modern Type 2 7kW unit can charge a BMW i3 from 10% to full in less than four hours, so overnight or working day charging is perfect. If you’re charging from a normal 13A domestic socket though, the charge cycle can take up to 12 hours.

This method of charging makes a 180 mile (290km) trip realistic in the very latest EVs and the best part is that it will only cost a few pounds/dollars in power versus £20/$16 or more in a petrol/gas or diesel vehicle. The main concern for most potential EV owners is when there is a need to travel further than the EVs range allows in one trip. What options are there to top up your battery when away from home? The good news is that in the UK for instance, there are now more than 14,000 public charging points with more than 25,000 connectors and better still, more than 2,500 of these are rapid chargers, where you can recharge your EV in roughly 30 minutes to 80% [23]. This scenario is similar in the USA, with more than 50,000 charging stations and 5,000 being rapid chargers. The downside is that many of these chargers are now pay as you use, although this still equates to roughly a third the cost of using an ICE v EV.

We have witnessed a significant change in public EV charger network infrastructure globally. Originally, there were disparate charge point operators and some car manufacturers, rolling out patchy charge point coverage, many in places that were hard to get to, or not on main highway routes. Fast forward a decade and the intervention of government and some manufacturers and the picture is completely different, helping establish contiguous coverage across European mainland, the UK and the USA.

With the advent of EVs now starting to become mainstream rather than a niche purchase, the charge-point networks need to start earning revenue to help pay for the huge investment of infrastructure roll-out and to pay for the electricity consumed. While not ideal, it does focus the EV users mind, with more drivers choosing to charge at home, due to the lower cost per electricity unit, especially if you charge on an off-peak tariff.

Car Charging and Mobile Control Application

Without exception, all new EVs now come with a mobile application that allows the driver to remotely manage the vehicle while it is parked on or off charge via Wi-Fi and 4G or 5G.

Some of the key features that are available for mobile remote monitoring and control are:

​» ​Charging status, energy consumption and emissions whilst remote from the car

​» ​Ability to remotely pre-heat or cool the vehicle prior to driving

​» ​Ability to delay charging until cheaper off-peak tariff energy starts

​» ​Check on charging and available range remotely

​» ​Check current location of car, track journeys and previous trips too

​» ​Monitors driving style with tips and shows how economically you have driven

​» ​Will alert you when charged, if you stop for a coffee to top up for instance

What do you think?

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