Ensuring the Safe Use of Mode 2 Charging Cables in Portable Level 2 Chargers

Where do the safety risks of Mode 2 charging cables come from?

Mode 2 products first originated in the U.S. market in 2010 to meet the charging needs of plug-in vehicles such as the LEAF and Volt, and were designed based on standards such as UL 2594, UL2231, and SAE J1772 for connecting charging between home outlets and vehicles. However, there are still the following problems:

I. Substandard user electrical conditions

Many EV owners do not have perfect private charging conditions. For example:

1.1 Vehicle owners do not have their own garages;

1.2 Car parking spaces do not have fixed power supply;

1.3 The installation standard of sockets is not uniform, and there are even non-standard phenomena such as "flying wire charging".

Once the basic electric facilities are not in place, the use of portable chargers will face greater safety risks.

2. Risks associated with household plugs and sockets

Many households are still using non-standard sockets or patch panels from the early days, which have thin internal wiring and poor contact, making it difficult for them to withstand high power loads for long periods of time. Portable Level 2 chargers often need to continuously output more than 10kWh of power, which puts higher requirements on the heat resistance and conductivity of plugs and sockets.

In order to solve this problem, the industry generally suggests adding temperature sensors (RTDs) in the plugs and sending them back to the control box through a signal line to realize the temperature control protection function. At present, this type of plug has been included in the CQC certification system, specific testing requirements include:

2.1 Protection against electric shock
2.2 Grounding and structural safety
2.3 Temperature rise and insulation test
2.4 Mechanical strength and aging test
2.5 Plugs and screws, electrical gaps, combustion resistance, etc.

3. Uncontrollable User Behavior

Even if the product design is safe, it is still difficult to regulate the unregulated behavior of users such as using aging sockets, using extension cords, and humid environments, which makes the safe use of Mode 2 rely more on the preventive mechanism of the product itself.

II. The technical path of the charging cable body

For the certification and improvement direction of Mode 2, especially the charging cable used in Portable Level 2 Charger, it can be designed from the following dimensions:

1. Front-end cable (plug to control box)

can be designed with reference to the standard of charging gun cable, and it is recommended to use the cable that has been certified by CQC, and combined with the temperature control cable unit, to enhance the performance of heat-resistant, cold-resistant, and UV-resistant aging. The design can be based on:

1.1 60227 IEC 53 (RVV) of GB 5023.5.

1.2 or 60227 IEC 57 (RVV-90)

1.3 or CQC1104 as amended (300/500V rating)

2. Back-end cable (control box to vehicle)

may be modeled after the fixed charge post cable configuration and typically includes:

2.1 Multi-stranded conductors

2.2 High strength insulation

2.3 Aramid yarn filled reinforcement

2.4 Inner and outer jacket protection

2.5 Waterproof and UV protection

This design guarantees electrical performance and can cope with complex outdoor environments.

III. Suggestions for Future Development

Although the environment for using Portable Level 2 Charger is complicated, the following measures are still expected to promote the compliance and scale application of Mode 2 products in the market:

3.1 Promote the renovation of parking lot electric facilities to create a more friendly "power" environment;

3.2 Improve the national standards and certification system to raise the threshold of access;

3.3 Promote smart plugs with temperature control protection to reduce the risk of misuse by users;

3.4 Strengthen user education and guide the correct use of Mode 2 products;

3.5 Strengthening the standardization and management of charging cable manufacturing enterprises.

With the rising demand for portable charging, Portable Level 2 Charger will play an increasingly important role in flexible deployment, emergency power replenishment, temporary charging etc.