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Charging ahead

9th July 2019


Jaguar I-PACE Jaguar I-PACE
Pantograph units support these buses Pantograph units support these buses
Ionity's first UK charger in Maidstone, Kent, Gretna Green and Milton Keynes are next Ionity's first UK charger in Maidstone, Kent, Gretna Green and Milton Keynes are next
An airfreight enclosure is used to house the charger package for this race series An airfreight enclosure is used to house the charger package for this race series
Charging infrastructure will be increasingly seen at supermarkets and restaurants Charging infrastructure will be increasingly seen at supermarkets and restaurants

Charging technology is absolutely crucial to the success of any electric machine. Oliver Johnson talks us through the current state-of-the-art

As the dust settles after the Extinction Rebellion climate change protests brought road traffic in central London to a standstill in April, there has never been more attention on greenhouse gas emissions and their impact on climate change. Adoption of electric vehicles (EVs) will be vital to bringing emissions under control, particularly in the 19 countries around the world that have made a commitment to become carbon neutral by 2050, including the UK, France, Canada, Denmark and Spain.

But one challenge to the widespread adoption of EVs is the need for suitable charging points to remove range anxiety.

Most charging points today are domestic points that supply alternating current (AC) straight from the grid. It needs to be converted to direct current (DC) to charge the battery.

To do this, EVs have an AC-DC converter but because space is limited inside car bodies, these are quite small, so the power capacity is limited to 7-11kW for most cars. If you’ve got a car with an 80kWh battery, such as a Jaguar I-PACE, Audi e-tron or a Tesla, it could take 8-12 hours or more to fully charge the battery.

That’s fine for a domestic setting but we know drivers want much faster charging times at other sites – which is possible with DC chargers. These roadside units house large and
powerful AC-DC converters that provide anything from 20–350kW, which can charge a large vehicle battery to 80% of capacity in under 15 minutes.

ABB has developed use cases that determine the most appropriate power rating for any particular site.

At the low end, homeowners are best off with a 3-22kW AC solution that provides a steady charge over 4-16 hours and doesn’t require them to upgrade their incoming supply.

However, for offices and commercial buildings, hotels and hospitality sites, car dealerships and commuter car parks, drivers expect to stay from one to threehours and 20-25kW DC charging power is acceptable.

The next level up is 50kW for 20-90 minute stays for sites such as supermarkets, restaurants and truck stops on the motorway. And the very highest power sites deliver charge in under 20 minutes for drivers at motorway service stations and convenience stops in city centres and the suburbs.
 
We are already seeing the deployment of DC charging infrastructure on highways. For example, Electrify America is deploying hundreds of high-power charging stations around 17 metropolitan areas in the US, as well as up to 120 miles apart along national highway corridors to overcome the range anxiety of car buyers. In the UK, the Ionity consortium of OEM car manufacturers is doing the same – its first site in Maidstone, Kent went live at the end of May. Others, such as Fastned, have already opened their first UK site.

What about large vehicles?

We’re also seeing deployment of high-power chargers for bus and truck fleets. In many ways, local bus services are the most suitable form of transport for EVs. They have predictable routes and operators can optimise routes and bus specifications with a relatively small battery that requires charging little and often – therefore freeing up space for passengers.

The technique of opportunity charging can provide these small and regular top-up charges throughout the day. As a result, buses do not have to return to the depot for recharging – meaning that 24-hour bus services are possible.

With opportunity charging, buses receive high power charge from an overhead pantograph that descends from a mast at the roadside. When a bus arrives at the stop, its WiFi connects to the charging point and triggers the pantograph to engage. Charging only takes a few minutes then the bus is ready to go back round its route.

Opportunity charging stations are based on exactly the same technology as DC charging points for cars, with the only difference being the automated overhead connector.

There are already many examples around the world. A fully electric and autonomous bus supplied by Volvo is in service at Nanyang Technological University in Singapore. Heavy vehicle chargers deliver 300kW DC power while passengers mount and dismount.

These type of charging masts can serve whole fleets of buses, such as in the Swedish city of Gothenburg, where a new fleet of 30 fully electric buses is set to enter service in October 2019, with power from opportunity charging stations at three stops along their route. In the UK, the market town of Harrogate is already operating three pantograph units in its bus depot to support buses running over long hours on eight routes. Birmingham Airport is due to start installing the same equipment to serve all-electric Volvo shuttle buses to transport passengers and staff to car parks.

However, trucks are also getting in on the act in anticipation of new ultra-low emission zones in major cities. Truck manufacturers are developing electric versions of their trucks and vans to meet demand from operators who want to avoid punitive fees for driving diesel powered vehicles in city centres.

What is inside a DC charger?

The AC/DC power converter is the main electrical component and typically comes in a modular format. These build up to deliver the desired rating.

However, the best approach to creating an EV charging point is to start with a really good processor and fast data connectivity – the ‘brains’ –  and build the power conversion ‘muscle’ around that.

This approach provides a seamless experience for drivers – for example, handling payment data and the electronic ‘handshake’ that happens when you plug a vehicle in. But it also lets the owner and operator of the charging point keep an eye on its performance from a remote control centre. It can give insight into the popularity of different sites, as well as the performance of converter modules, for example by raising alerts to send a technician if a converter module needs to be replaced.
 
The true test of any technology in the field comes over time. In the case of EV charging points, they will need to withstand extremes of summer heat, winter cold, rain and snow, as well as mechanical wear and tear.

As the main support series to the ABB FIA Formula E Championship, the Jaguar I-Pace eTrophy Championship is a test-bed for the cars and their chargers in the most extreme conditions.

The high-power chargers used for the series contain identical components to the roadside technology, although they are repackaged in an air-freight enclosure so they can follow the series to 10 races around the world. Once in place at a circuit, the chargers must
work perfectly, whether in the heat of Saudi Arabia or at the Jaguar Land Rover Ice Academy in Arjeplog in Sweden.

According to Chris Crump, Southern Europe Operations team leader for Jaguar Land Rover: “The ABB chargers at the Ice Academy are one of the most northerly of all DC charging infrastructure across Europe, and it is one of the most remote and coldest installations on the planet. The stations have been designed to perform in extreme conditions, from -35°C to 55°C.”

Where does the future lie?

Car manufacturers are actively developing cars with bigger batteries for longer range, with one example being Porsche’s first fully electric car, the Taycan, which is due to go into production in 2020.

The industry is very much focused on lithium-ion batteries. Although there has been a lot of discussion about other types of battery with higher energy densities, these are the subject of research and development for now. But when they are available, they will inevitably enable vehicle manufacturers to further extend the range of their vehicles – and this will only drive further demand for DC fast charging stations.

Oliver Johnson is development manager for EV charging at ABB







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