Charging station

Charging stations for electric vehicles: Top-left: a Tesla Roadster being charged at an electric charging station in Iwata city, Japan. Top-right: Nissan Leaf recharging from a NRG Energy eVgo station in Houston, Texas. Bottom-left: converted Toyota Priuses recharging at public charging stations in San Francisco (2009). Bottom-right: Brammo Empulse electric motorcycle at an AeroVironment charging station.

An electric vehicle charging station, also called EV charging station, electric recharging point, charging point, charge point and EVSE (Electric Vehicle Supply Equipment), is an element in an infrastructure that supplies electric energy for the recharging of electric vehicles, such as plug-in electric vehicles, including electric cars, neighborhood electric vehicles and plug-in hybrids.

As plug-in hybrid electric vehicles and battery electric vehicle ownership is expanding, there is a growing need for widely distributed publicly accessible charging stations, some of which support faster charging at higher voltages and currents than are available from residential EVSEs. Many charging stations are on-street facilities provided by electric utility companies or located at retail shopping centers and operated by many private companies. These charging stations provide one or a range of heavy duty or special connectors that conform to the variety of electric charging connector standards.

Contexts

Charging stations fall into four basic contexts:

1. Residential charging stations: An EV owner plugs in when he or she returns home, and the car recharges overnight. A home charging station usually has no user authentication, no metering, and may require wiring a dedicated circuit. Some portable chargers can also be wall mounted as charging stations.
2. Charging while parked (including public charging stations) – a commercial venture for a fee or free, offered in partnership with the owners of the parking lot. This charging may be slow or high speed and encourages EV owners to recharge their cars while they take advantage of nearby facilities. It can include parking stations, parking at malls, small centres, and train stations (or for a business's own employees).
3. Fast charging at public charging stations >40 kW, delivering over 60 miles (100 km) of range in 10–30 minutes. These chargers may be at rest stops to allow for longer distance trips. They may also be used regularly by commuters in metropolitan areas, and for charging while parked for shorter or longer periods. Common examples are CHAdeMO and SAE CCS chargers, and Tesla Superchargers.
4. Battery swaps or charges in under 15 minutes. A specified target for CARB credits for a zero-emission vehicle is adding 200 miles to its range in under 15 minutes. In 2014, this was not possible for charging electric vehicles, but it is achievable with EV battery swaps and Hydrogen Fuel Cell vehicles. It intends to match the refueling expectations of regular drivers.

Battery capacity and the capability of handling faster charging are both increasing, and methods of charging have needed to change and improve. New options have also been introduced (on a small scale, including mobile charging stations and charging via inductive charging mats). The differing needs and solutions of various manufacturers has slowed the emergence of standard charging methods, and in 2015, there is a strong recognition of the need for standardization.

Overview

International status

As of December 2012, around 50,000 non-residential charging points were deployed in the U.S., Europe, Japan and China.^[1] As of August 2014, there are 3,869 CHAdeMO quick chargers deployed around the world, with 1,978 in Japan, 1,181 in Europe and 686 in the United States, 24 in other countries.^[2] As of December 2013, Estonia is the first and only country that had completed the deployment of an EV charging network with nationwide coverage, with 165 fast chargers available along highways at a maximum distance of between 40 to 60 km (25 to 37 mi), and a higher density in urban areas.^[3][4][5]

As of March 2013, 5,678 public charging stations existed across the United States, with 16,256 public charging points, of which 3,990 were located in California, 1,417 in Texas, and 1,141 in Washington.^[6][7] As of November 2012, about 15,000 charging stations had been installed in Europe.^[8]

As of March 2013, Norway, which has the highest electric ownership per capita, had 4,029 charging points and 127 quick charging stations.^[9] As part of its commitment to environmental sustainability, the Dutch government initiated a plan to establish over 200 fast (DC) charging stations across the country by 2015. The rollout will be undertaken by Switzerland-based power and automation company ABB and Dutch startup Fastned, and will aim to provide at least one station every 50 kilometres (31 miles) for the Netherlands' 16 million residents.^[10] In addition to that, the E-laad foundation installed about 3000 public (slow) charge points since 2009.^[11]

As of December 2012, Japan had 1,381 public quick-charge stations, the largest deployment of fast chargers in the world, but only around 300 slow chargers.^[1] As of December 2012, China had around 800 public slow charging points, and no fast charging stations.^[1] As of December 2012, the country with the highest ratio of quick chargers to electric vehicles (EVSE/EV) was Japan, with a ratio of 0.030, and the Netherlands had the largest ratio of slow EVSE/EV, with more than 0.50, while the U.S had a slow EVSE/EV ratio of 0.20.^[1]

As of September 2013, the largest public charging networks in Australia exist in the capital cities of Perth and Melbourne, with around 30 stations (7 kW AC) established in both cities – smaller networks exist in other capital cities.^[12]

Safety

Although the rechargeable electric vehicles and equipment can be recharged from a domestic wall socket, a charging station is usually accessible to multiple electric vehicles and has additional current or connection sensing mechanisms to disconnect the power when the EV is not charging.

There are two main types of safety sensor:

• Current sensors which monitor the power consumed, and maintain the connection only if the demand is within a predetermined range. Sensor wires react more quickly, have fewer parts to fail and are possibly less expensive to design and implement. Current sensors however can use standard connectors and can readily provide an option for suppliers to monitor or charge for the electricity actually consumed.
• Additional physical 'sensor wires' which provide a feedback signal such as specified by the undermentioned SAE J1772 and IEC 62196 schemes that require special (multi-pin) power plug fittings.

Until 2013, there was an issue where Blink chargers were overheating and causing damage to both charger and car.^[13][14] The solution employed by the company was to reduce the maximum current.^[15]

Standards

In SAE terminology, 240 volt AC charging is known as Level 2 charging, and 500 volt DC high-current charging is known as DC Fast Charge. Owners can install a level 2 charging station at home, while businesses and local government provide level 2 and DC Fast Charge public charging stations that supply electricity for a fee or free.

The International Electrotechnical Commission modes definition (IEC 62196):

• Mode 1 – slow charging from a regular electrical socket (single- or three-phase)
• Mode 2 – slow charging from a regular socket but which equipped with some EV specific protection arrangement (e.g., the Park & Charge or the PARVE systems)
• Mode 3 – slow or fast charging using a specific EV multi-pin socket with control and protection functions (e.g., SAE J1772 and IEC 62196)
• Mode 4 – fast charging using some special charger technology such as CHAdeMO

There are three connection cases:

• Case A is any charger connected to the mains (the mains supply cable is usually attached to the charger) usually associated with modes 1 or 2.
• Case B is an on-board vehicle charger with a mains supply cable which can be detached from both the supply and the vehicle – usually mode 3.
• Case C is a dedicated charging station with DC supply to the vehicle. The mains supply cable may be permanently attached to the charge-station such as in mode 4.

There are four plug types:

• Type 1 – single-phase vehicle coupler – reflecting the SAE J1772/2009 automotive plug specifications
• Type 2 – single- and three-phase vehicle coupler – reflecting the VDE-AR-E 2623-2-2 plug specifications
• Type 3 – single- and three-phase vehicle coupler equipped with safety shutters – reflecting the EV Plug Alliance proposal
• Type 4 – fast charge coupler – for special systems such as CHAdeMO

Residential charging

Mode 1: Household socket and extension cord

The vehicle is connected to the power grid through standard socket-outlets present in residences, which depending on the country are usually rated at around 10 A. To use mode 1, the electrical installation must comply with the safety regulations and must have an earthing system, a circuit breaker to protect against overload and an earth leakage protection. The sockets have blanking devices to prevent accidental contacts.

The first limitation is the available power, to avoid risks of:

• Heating of the socket and cables following intensive use for several hours at or near the maximum power (which varies from 8 to 16 A depending on the country).
• Fire or electric injury risks if the electrical installation is obsolete or if certain protective devices are absent.

The second limitation is related to the installation's power management.

• As the charging socket shares a feeder from the switchboard with other sockets (no dedicated circuit) if the sum of consumptions exceeds the protection limit (in general 16 A), the circuit-breaker will trip, stopping the charging.

All these factors impose a limit on the power in mode 1, for safety and service quality reasons. This limit is currently being defined, and the value of 10 A appears to be the best compromise.

Mode 2: Domestic socket and cable with a protection device

The vehicle is connected to the main power grid via household socket-outlets. Charging is done via a single-phase or three-phase network and installation of an earthing cable. A protection device is built into the cable. This solution is more expensive than Mode 1 due to the specificity of the cable.

Mode 3: Specific socket on a dedicated circuit

The vehicle is connected directly to the electrical network via specific socket and plug and a dedicated circuit. A control and protection function is also installed permanently in the installation. This is the only charging mode that meets the applicable standards regulating electrical installations. It also allows loadshedding so that electrical household appliances can be operated during vehicle charging or on the contrary optimise the electric vehicle charging time.

Mode 4: Direct current (DC) connection for fast recharging

The electric vehicle is connected to the main power grid through an external charger. Control and protection functions and the vehicle charging cable are installed permanently in the installation.

Infrastructure

Charging stations for electric vehicles may not need much new infrastructure in developed countries, less than delivering a new alternative fuel over a new network.^[16] The stations can leverage the existing ubiquitous electrical grid and home recharging is an option. For example, polls have shown that more than half of homeowners in the USA have access to a plug to charge their cars. Also most driving is local over short distances which reduces the need for charging mid-trip. In the USA, for example, 78% of commutes are less than 40 miles (64 km) round-trip.^[17] Nevertheless, longer drives between cities and towns require a network of public charging stations or another method to extend the range of electric vehicles beyond the normal daily commute. One challenge in such infrastructure is the level of demand: an isolated station along a busy highway may see hundreds of customers per hour if every passing electric vehicle has to stop there to complete the trip. In the first half of the 20th century, internal combustion vehicles faced a similar infrastructure problem.

Charging time

The battery capacity of a fully charged electric vehicle from electric vehicle automakers (such as Nissan) is about 20 kWh, providing it with an electrical autonomy of about 100 miles. Tesla Motors released their Model S with battery capacities of 60 kWh and 85 kWh with the latter having an estimated range of approximately 480 km. Plug in hybrid vehicles have capacity of roughly 3 to 5 kWh, for an electrical autonomy of 20 to 40 kilometres, but the gasoline engine ensures the full autonomy of a conventional vehicle.

As the electric-only autonomy is still limited, the vehicle has to be charged every two or three days on average. In practice, drivers plug in their vehicles each night, thus starting each day with a full charge.

For normal charging (up to 7.4 kW), car manufacturers have built a battery charger into the car. A charging cable is used to connect it to the electrical network to supply 230 volt AC current. For quicker charging (22 kW, even 43 kW and more), manufacturers have chosen two solutions:

• Use the vehicle's built-in charger, designed to charge from 3 to 43 kW at 230 V single-phase or 400 V three-phase.
• Use an external charger, which converts AC current into DC current and charges the vehicle at 50 kW (e.g. Nissan Leaf) or more (e.g. 120-135 kW Tesla Model S).

Charging time for 100 km of BEV range	Power supply	Power	Voltage	Max. current
6–8 hours	Single phase	3.3 kW	230 V AC	16 A
3–4 hours	Single phase	7.4 kW	230 V AC	32 A
2–3 hours	Three phase	10 kW	400 V AC	16 A
1–2 hours	Three phase	22 kW	400 V AC	32 A
20–30 minutes	Three phase	43 kW	400 V AC	63 A
20–30 minutes	Direct current	50 kW	400–500 V DC	100–125 A
10 minutes	Direct current	120 kW	300–500 V DC	300–350 A

The user finds charging an electric vehicle as simple as connecting a normal electrical appliance; however to ensure that this operation takes place in complete safety, the charging system must perform several safety functions and dialogue with the vehicle during connection and charging.

Deployment of public charging stations

Currently charging stations are being installed by public authorities, commercial enterprises and some major employers in order to stimulate the market for vehicles that use alternative fuels to gasoline and diesel fuels. For this reason, most charge stations are currently either provided gratis or accessible to members of certain groups without significant charge (e.g. activated by a free "membership card" or by a digital "day code").

Locations

Charging stations can be found and will be needed where there is on-street parking, at taxi stands, in parking lots (at places of employment, hotels, airports, shopping centers, convenience shops, fast food restaurants, coffeehouses etc.), as well as in driveways and garages at home. Existing filling stations may also incorporate charging stations.

Vehicle and charging station projects and joint ventures

Electric car manufacturers, charging infrastructure providers, and regional governments have entered into many agreements and ventures to promote and provide electric vehicle networks of public charging stations.

The EV Plug Alliance^[18] is an association of 21 European manufacturers which proposes an alternative connecting solution. The project is to impose an IEC norm and to adopt a European standard for the connection solution with sockets and plugs for electric vehicle charging infrastructure. Members (Schneider Electric, Legrand, Scame, Nexans, etc.) argue that the system is safer because they use shutters. General consensus is that the IEC 62196 and IEC 61851-1 already have taken care of safety by making parts non-live when touchable.^[19][20][21]

Charging station manufacturers

The principal suppliers and manufacturers of charging stations offer a range of options from simple charging posts for roadside use, charging cabinets for covered parking places to fully automated charging stations integrated with power distribution equipment^[22]

DC charging stations (fast)

These companies (among AC slow-charging stations) design and manufacture DC Fast charging stations (less than 30 minutes). These systems may offer a restricted charge (stops at 80% SOC), or changes charging rate to a lower level after the 80% SOC is reached.

• Andromeda Power^[23] (Stations with CHAdeMO, ISO61851 and SAE Combined Charging System CCS) power input from Solar Panel (S2V) and from another vehicle (V2V).
• EVTRONIC^[24] (Stations with CHAdeMO, ISO61851 and SAE Combined Charging System CCS) .
• Bosch Automotive Service Solutions Inc.^[25] (Stations with SAE Combined Charging System CCS).
• Eaton^[26] (Stations with CHAdeMO and SAE Combined Charging System CCS) (US and Canada) up to 1 MW.
• EFACEC ^[27] (Stations with CHAdeMO and CCS (E.U. or U.S.) (CCS)
• ABB^[28] (Stations with CHAdeMO and CCS)
• AeroVironment
• Fuji Electric^[29] and ^[30]
• Schneider Electric
• Signet Systems
• Delta Electronics^[31][32][33] (Stations with CHAdeMO certified)
• Valent Power

Charging network operators

An operator manages charging stations.

• Car Charging Group
• ChargePoint
• eVgo

Feud

Reports emerged in late July 2013 of a significant conflict between the companies responsible for the two types of charging plugs. The Japanese-developed CHAdeMO standard is favored by Nissan, Mitsubishi, and Toyota, while the Society of Automotive Engineers’ (SAE) International J1772 Combo standard is backed by GM, Ford, Volkswagen, and BMW. Both are direct-current quick-charging systems designed to charge the battery of an electric vehicle to 80 percent in approximately 20 minutes, but the two systems are completely incompatible. In light of an ongoing feud between the two groups, experts in the field warned that the momentum of the electric vehicle market will be severely affected.^[34][35] Richard Martin, editorial director for clean technology marketing and consultant firm Navigant Research, stated:

Fast charging, however and whenever it gets built out, is going to be key for the development of a mainstream market for plug-in electric vehicles. The broader conflict between the CHAdeMO and SAE Combo connectors, we see that as a hindrance to the market over the next several years that needs to be worked out.^[35]

As of September 16, 2013, a standard does not exist in Australia for charging connectors. Australia’s first fast-DC charging stations follow the Japanese ChaDeMo standard.^[12]

EV charging station signs

In the United States, the standard charging station sign is defined in the Federal Highway Administration's Manual on Uniform Traffic Control Devices (MUTCD) 2009 edition.^[36]

See two examples of "D9-11b Electric Vehicle Charging" and "D9-11bP Electric Vehicle Charging" at "Figure 2I-1. General Service Signs and Plaques", page 301, Sect. 2I.02

In July 2013, FHWA released interim MUTCD approval for charging station signs located on public roads governed by MUTCD standards.^[37]

There is an open source, public domain European charge station sign proposed.^[38]

Block heater power supplies

In colder areas such as Finland, some northern US states and Canada there already exists some infrastructure for public power outlets provided primarily for use by block heaters and set with circuit breakers that prevent large current draws for other uses. These can sometimes be used to recharge electric vehicles, albeit slowly.^[39] In public lots, some such outlets are turned on only when the temperature falls below -20 °C, further limiting their use.^[40]

Battery swapping

A battery swapping (or switching) station is a place at which a vehicle's discharged battery or battery pack can be immediately swapped for a fully charged one, eliminating the delay involved in waiting for the vehicle's battery to charge.

Battery swapping is common in warehouses using electric forklift trucks.^[41] The concept of an exchangeable battery service was first proposed as early as 1896, in order to overcome the limited operating range of electric cars and trucks. It was first put into practice between 1910 to 1924, by Hartford Electric Light Company, through the GeVeCo battery service, and was initially available for electric trucks. The vehicle owner purchased the vehicle, without a battery, from General Vehicle Company (GeVeCo), part-owned by General Electric,^[42] and the electricity was purchased from Hartford Electric through the use of an exchangeable battery. Both vehicles and batteries were modified to facilitate a fast battery exchange. The owner paid a variable per-mile charge and a monthly service fee to cover maintenance and storage of the truck. During the period of the service, the vehicles covered more than 6 million miles.

Beginning in 1917, a similar successful service was operated in Chicago for owners of Milburn Electric cars, who also could buy the vehicle without the batteries.^[43] A rapid battery replacement system was implemented to keep running 50 electric buses at the 2008 Summer Olympics.^[44]

In recent years, Better Place, Tesla Motors, and Mitsubishi Heavy Industries have been involved with integrating battery switch technology with their electric vehicles to extend driving range.^[45][46] In a battery switch station, the driver does not need to get out of the car while the battery is swapped.^[47] Battery swap requires an electric car designed for the "easy swap" of batteries. However, electric vehicle manufacturers working on battery switch technology have not standardized on battery access, attachment, dimension, location, or type.

Tesla Motors announced a proprietary charging station service to support owners of Tesla Model S automobiles in the summer of 2013. A network of Tesla stations was supposed to support both battery pack swaps for the Model S, along with the more-widespread fast charging capability for both the Model S and the Tesla Roadster.^[48][49] However, only one such station has been built, at Harris Ranch, on Interstate 5 in California.^[50]

The following benefits are claimed for battery swapping:

• Fast battery swapping under five minutes.^[51][52]
• Unlimited driving range where there are battery switch stations available.^[53]
• The driver does not have to get out of the car while the battery is swapped.^[54]
• The driver does not own the battery in the car, transferring costs over the battery, battery life, maintenance, capital cost, quality, technology, and warranty to the battery switch station company.^[55]
• Contract with battery switch company could subsidize the electric vehicle at a price lower than equivalent petrol cars.^[56]
• The spare batteries at swap stations could participate in vehicle to grid storage.

Better Place

The Better Place network was the first modern commercial deployment of the battery switching model. The Renault Fluence Z.E. was the first electric car enabled with switchable battery technology available for the Better Place network in operation in Israel and Denmark.^[57] Better Place used the same technology to swap batteries that F-16 jet fighter aircraft use to load their bombs.^[58] Better Place launched its first battery-swapping station in Israel, in Kiryat Ekron, near Rehovot in March 2011. The battery exchange process took five minutes.^[51][59] As of December 2012, about 600 Fluence Z.E.s had been sold in the country. Sales during the first quarter of 2013 improved, with 297 cars sold, bringing the total fleet in Israel close to 900.^[60] As of December 2012, there were 17 battery switch stations fully operational in Denmark, enabling customers to drive anywhere across the country in an electric car.^[61] Fluence Z.E. sales totaled 198 units through December 2012.^[62]

Better Place filed for bankruptcy in Israel in May 2013. The company's financial difficulties were caused by the high investment required to develop the charging and swapping infrastructure, about US$850 million in private capital, and a market penetration significantly lower than originally predicted by Shai Agassi. Fewer than 1,000 Fluence Z.E. cars had been deployed in Israel and only around 400 units in Denmark.^[63][64] Under Better Place's business model, the company owned the batteries, so the court liquidator had to decide what to do with customers who did not have ownership of the battery and risked being left with a useless car.^[65]

Tesla Motors

Tesla Motors designed its Model S to allow fast battery swapping.^[45] In June 2013, Tesla announced its goal of deploying a battery swapping station in each of its supercharging stations. At a demonstration event, Tesla showed that a battery swap operation with the Model S took just over 90 seconds, about half the time it takes to refill a gasoline-powered car used for comparison purposes during the event.^[52][66]

The first stations were planned to be deployed along Interstate 5 in California because, according to Tesla, a large number of Model S sedans make the San Francisco-Los Angeles trip regularly. Those stations were to be followed by ones on the Washington, DC to Boston corridor. Elon Musk said the service would be offered for the price of about 15 US gallons (57 l; 12 imp gal) of gasoline at the current local rate, around US$60 to US$80 at June 2013 prices. Owners could pick up their battery pack fully charged on the return trip, which was included in the swap fee. Tesla would also offer the option to keep the pack received on the swap and pay the price difference if the battery received was newer, or to receive the original pack back from Tesla for a transport fee. Pricing had not been determined.^[52]

In June 2015, Musk indicated that Tesla was likely to abandon its plans to build a network of swap stations. He told his company's shareholders that, despite inviting all Model S owners in the California area to try out the one existing facility, at Harris Ranch, about half way between San Francisco and Los Angeles, only four or five people had done so, and then only once. Consequently, it was unlikely that the concept was worth expanding.^[50]

Gogoro Energy Network

Gogoro has announced their intention to launch the Gogoro Energy Network in 2015. The network is built on the idea of distributed GoStations which will serve as battery swapping locations for Gogoro's Smartscooters.

BattSwap

BattSwap is a new European start-up with battery swap solution. It has a working prototype covered by seed funding received from European angels. Swap station takes only 30 seconds to make a complete swap and is 10x cheaper than Tesla supercharger to build.

Criticism

These battery swapping solution have been criticized for being proprietary. By creating a monopoly regarding the ownership of the batteries and the patent protected technologies the companies split up the market and decrease the chances of a wider usage of battery swapping.^[67]

Related Technologies

Smart grid communication

Recharging a large battery pack presents a high load on the electrical grid, but this can be scheduled for periods of reduced load or reduced electricity costs. In order to schedule the recharging, either the charging station or the vehicle can communicate with the smart grid. Some plug-in vehicles allow the vehicle operator to control recharging through a web interface or smartphone app.^[68] Furthermore, in a Vehicle-to-grid scenario the vehicle battery can supply energy to the grid at periods of peak demand. This requires additional communication between the grid, charging station, and vehicle electronics. SAE International is developing a range of standards for energy transfer to and from the grid including SAE J2847/1 "Communication between Plug-in Vehicles and the Utility Grid".^[69] ISO and IEC are also developing a similar series of standards known as ISO/IEC 15118: "Road vehicles -- Vehicle to grid communication interface".

Renewable electricity and RE charging stations

Charging stations are usually connected to the electrical grid, which often means that their electricity originates from fossil-fuel power stations or nuclear power plants. Solar power is also suitable for electric vehicles. SolarCity is marketing its solar energy systems along with electric car charging installations. The company has announced a partnership with Rabobank to make electric car charging available for free to owners of Tesla Motors' vehicles traveling on Highway 101 between San Francisco and Los Angeles. Other cars that can make use of same charging technology are welcome.^[70]

Several Chevrolet Volts at a charging station powered with solar panels in Frankfort, Illinois.

SPARC station

The SPARC (Solar Powered Automotive ReCharging Station) uses a single custom fabricated monocrystalline solar panel capable of producing 2.7 kW of peak power to charge pure electric or plug-in hybrid to 80% capacity without drawing electricity from the local grid. Plans for the SPARC include a non-grid tied system as well as redundancy for tying to the grid through a renewable power plan. This supports their claim for net-zero driving of electric vehicles.

E-Move charging station

The E-Move Charging Station is equipped with eight monocrystalline solar panels, which can supply 1.76 kWp of solar power. With further refinements, the designers are hoping to generate about 2000 kWh of electricity from the panels over the year.^[71]

Wind-powered charging station

In 2012, Urban Green Energy introduced the world's first wind-powered electric vehicle charging station, the Sanya SkyPump. The design features a 4 kW vertical-axis wind turbine paired with a GE WattStation.^[72]

See also

Notes

Wikimedia Commons has media related to Electric vehicle charging stations.