Battery electric vehicles (EVs) have seen rapidly growing sales figures in recent years. There are several reasons to consider an EV besides saving gas. The highlight, of course, is the environment. EVs have no tailpipe emissions and research shows they are responsible for lower levels of greenhouse gases (GHG) than the average new (and old) gasoline car.
EVs are also becoming a more affordable alternative to conventional vehicles – especially over time. They offer lower operating costs and cheaper maintenance than gas guzzlers over a period of five years or more.
Charging infrastructure, a fundamental accessory for EVs, is constantly developing. Unfortunately, EV plug standards are not universal and vary by city and country. In this article, we will discuss several different types of vehicle-side EV connectors and compare them. We will also discuss why specific types of connectors are adopted in different regions.
The charging stations
A charging cable has two connectors – one plugs into the vehicle's socket and the other plugs into the charging station. Electric vehicles charge in a similar way to cell phones.
There are two types of charging stations for EVs. One of them is slow/fast charging stations typically installed in homes and offices for recharging. These stations draw AC power from a main power source, taking several hours to charge the vehicles. Often, electric vehicle owners charge their vehicles overnight using these stations.
The other type is a fast or high-speed charging station installed in public places or on major highways. They directly charge the vehicle's battery with DC power, usually in less than half an hour. However, DC fast charging should not be done more than once or twice a week as it has a detrimental effect on battery life.
Fast charging is best suited for long trips, while overnight slow/fast charging is ideal for daily commutes. There are different EV charging connectors for slow/fast AC charging and DC fast charging.
AC Charging Connectors
The following EV charging connectors are used for AC charging.
1. Type 1 connector (J1772/IEC60309)
2. Type 2 connector (Mennekes/IEC62196)
3.GB/T
The Type 1 Connector is the standard US connector for EVs with AC charging, although you'll also find it throughout Japan. It has five pins and has no locking mechanism. These connectors charge EVs using single-phase AC from the electrical grid.
Typical powers are 3.7 and 7 kW, capable of charging 20 and 40 km of autonomy per hour, respectively. The connector is a 15V outlet with region-based AC frequency. The output voltage is indicated by the color of the cable. For 50~60 Hz AC, a yellow cable indicates 100~130V output; a blue cable indicates 200~250V output; and a red cable indicates 380~480V output.
Adaptation is generally done outdoors. The connector is weatherproof to IP44 standard.
Type 2 Connector is the EU standard connector for AC charging EVs and is quite common in India. It has seven pins with a built-in locking mechanism. These connectors are capable of charging EVs with single-phase and three-phase ACs.
Typical power ratings for single-phase AC charging are 3.7 and 7 kW, capable of charging a range of 20 and 40 km per hour, respectively. Three-phase charging has a power of 22 kW, capable of charging up to 120 km of autonomy per hour. Of the seven pins, three are line phase, two are signaling pins, one pin is ground and one is neutral.
The GB/T connector is mainly used in China. The connector has seven pins with a built-in locking mechanism. There are two charging modes – one with 250V output and the other with 440V output. Both charging modes have a maximum power of 27.7 kW.
No three-pin plugs please
There are reasons why typical three-prong household plugs are not used to charge EVs. For one, they cannot produce more than 10Wh and do not provide two-way communication. Additionally, they are not weatherproof and are intended for indoor use only.
DC charging connectors
The following EV charging connectors are used for DC fast charging.
1. CHAdeMO
2. Combined Charging System (CCS)
3.GB/T
CHAdeMO is the original DC connector developed by the Japanese dealership Tepco and is normally only used in Japan. With a 125A socket, the connector can supply powers of 50 and 100 kW, capable of charging for a range of 120 and 240 km per hour, respectively.
The latest CHAdeMO EV 2.0 connector specification can provide a rated power of 400 kW. This connector uses CAN protocol for communication between EVs and the charging station.
The Combined Charging System (CCS) is the EU's fast charging standard. It is based on the J1772 connector and includes two additional pins, allowing high-speed charging on J1772 connectors making a 2-pin Type 2 arrangement.
This connector can provide power rates of 50, 150 and 350 kW, charging range of 120, 360 and 840 km per hour, respectively.
In North America, CCS1 is the default plug type, while in the EU CCS2 is the default plug type. Both CCS1 and CCS2 have the same DC pin architecture and communication protocol. The CCS connector uses PLC for communication between the EVs and the charging station.
The GB/T Connector is mainly used in China for DC fast charging. It has an output voltage of 750/1000V and a rated current of 80~250A. Maximum power is 250 kW.
Tesla
Tesla has proprietary connectors, although it has begun adopting CCS connectors for DC charging. CCS and CHAdeMO connectors are also in the process of converging efforts to support universal charger standards.
The regions
In North America, the Type 1 connector is the standard plug type for AC charging and the CCS1 for DC charging. In Japan, the Type 1 connector is also the standard type for AC charging, while CHAdeMO is used for DC charging. In EU and India, Type 2 connector is the standard plug type for AC charging and CCS2 is used for DC fast charging. GB/T is the standard plug type in China. In India, many automobile manufacturers also use CHAdeMO and GB/T for DC charging of EVs.
A universal standard
There are several reasons why there are different socket architectures for charging electric vehicles in different parts of the world. For AC charging, variations arose due to different power supplies. For DC charging, the differences are related to the origin of the charging technology. China has its own charging socket standards due to state policies.
Automotive manufacturers and organizations are moving to a universal plug standard. For example, the CCS and CHAdeMO standards are in the process of converging. But a one-size-fits-all global electric vehicle charging infrastructure may never happen. Time will tell.
