IEC releases final draft Standards for electric vehicle charging

Issue 32 – October 2011

The latest set of IEC International Standards for electric vehicles (EVs) is nearing completion with the circulation of two final draft Standards, IEC 62196-1 and IEC 62196-2. These define the plugs and sockets for charging EVs and are outlined below.

These IEC Standards pull together the huge volume of diverse research and development surrounding EV charging mechanisms from around the world whilst addressing the diverse electricity infrastructures and regulations in different countries.

In the past, these factors have meant there is a very real risk that incompatible solutions will be developed by separate businesses in different global regions. This would be against the best interests of the worldwide vehicle manufacturing industry, as addressed during this year's Frankfurt Motor Show (IAA).

IAA is the largest annual global gathering of motor manufacturers and this year had its biggest ever focus on EVs, including a whole exhibition hall dedicated to electromobility and a clutch of specialist conferences. One of these, the Electric Mobility Congress, recognized how different national approaches are thwarting the mass marketability of EVs and several significant manufacturers, including Bosch, called for international Standardisation. The technical Standards being put forward by the IEC respond to these calls.

Formulating these has been difficult because of the problems outlined above. However, because of IEC's well-established process and international approach there is a high level of confidence that they will enable global interoperability, allowing vehicle manufactures' products to operate across as wide a range of markets as possible.

EV charging Standards

The two final draft Standards define the plugs and sockets which can be used to charge an EV. IEC 62196-1 contains the general requirements while IEC 62196-2 standardises three types of mains connecting systems, known as Types 1, 2 and 3. Which of these is appropriate depends largely upon the electrical infrastructure and regulatory conditions in each country.

These Standards build upon IEC 61851-1, which defines the four modes of charging an EV from a power source. Modes 1 to 3 are estimated to allow an EV to be fully charged in between three and ten hours through direct connection to a mains supply. Mode 4 could fully charge an EV in under ten minutes, but as it uses off-grid batteries it is the most expensive to implement.

The new general IEC 62196-1 Standard applies to all four of these modes while IEC 62196-2 applies only to mains charging (Modes 1 to 3). A third Standard, IEC 62196-3, is being developed to Standardise DC charging (Mode 4).

In addition, IEC 61851-1 defines three cable and plug setups, which can be used to charge EVs: Case A, where the cable is permanently attached to the EV; Case B, where the cable is not permanently attached to anything; and Case C where the cable is permanently attached to the charging station.

Standards to match regulatory parameters

Taken together these Types, Modes and Cases allow manufacturers to work to common Standards within which they can meet the regulatory requirements across differing markets. For example, Italy and the United States have limited Mode 1 charging on safety grounds, while Mode 3 is receiving a lot of interest in the United States and Europe for public charging points and Mode 4 is favoured in Japan.

Furthermore, technical constraints mean all Mode 4 cables need to be permanently attached to the charging station (Case C) and United States regulations demand that Mode 3 charging stations also have Case C cables.

The new draft Standards, IEC 62196-1 and IEC 62196-2, bring further clarification to this picture by defining the plugs and sockets, which can be used according to differing electricity infrastructures. For example, the United States and Japan currently favour Type 1 connectors, some European countries favour Type 2 connectors and other countries' regulations mean Type 3 connectors could be required.

IEC Standards setting a baseline for EV development

As can be seen from this brief overview, existing regulations and electricity distribution networks are already shaping how the provision of EV charging stations is being developed. Left unchecked this could lead to a situation where vehicle manufacturers would have to produce a new model of each car in order to meet the EV charging requirements of each country.

IEC's Standards will help prevent this from happening by defining a set of options which each country and manufacturer can choose from according to their requirements. This will ensure that EVs and the components needed to charge them can be used in as many countries as possible, bringing down costs for manufacturers and potentially increasing EV attractiveness to consumers.

The IEC International Standards IEC 62196-1 and IEC 62196-2 are due to be published within the next few months, at which time a more in-depth technical overview of them will be provided.

Published in transport.