The Comparison of Liquid Cooled EV Charging Cables and Naturally Cooled Charging Cables

In the fast-evolving world of electric vehicles (EVs), the charging infrastructure plays a pivotal role. EV charging cable is a crucial component, which is a specialized cable used to connect an electric vehicle (EV) to a charging station.It allows the transfer of electrical energy from the charging station to the EV's battery. There are two main types are liquid cooled EV charging cables and naturally cooled (usually air-cooled) ones. Understanding their differences and characteristics is essential for optimizing EV charging systems.

I. Cooling Mechanisms

1. Liquid Cooled EV Charging Cables
   • Liquid cooled EV charging cables utilize a coolant, such as a water-glycol mixture or biodegradable oils. The coolant circulates within the cable, absorbing the heat generated by the electrical current passing through the conductors. This allows for efficient heat dissipation, maintaining the cable at a relatively stable temperature even during high-power charging.
   • For example, in some advanced liquid cooled cable designs, the coolant is pumped through channels adjacent to the conductors, ensuring rapid heat transfer away from the high-current-carrying parts.
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2. Naturally Cooled Charging Cables
   • Naturally cooled cables rely on ambient air for heat dissipation. They typically have a simple design with exposed conductors or insulated conductors that allow heat to passively transfer to the surrounding air.
   • In normal operation, as the current passes through the cable, the heat causes the temperature of the cable to rise. The warmer cable then heats the adjacent air, and through natural convection, the heated air rises and is replaced by cooler air, gradually dissipating the heat. However, this process is relatively slow compared to liquid cooling.
     

II. Heat Dissipation Efficiency

1. Liquid Cooled Cables
   • Have a significantly higher heat dissipation efficiency. They can handle much higher power levels without overheating. For instance, liquid cooled cables can support charging currents of up to 600A or more, enabling rapid charging of EVs. This is because the coolant has a high specific heat capacity and can absorb and carry away large amounts of heat quickly. As an professional manufacturer Fiver New Energy have introduced liquid cooled charging cables in different standards, such as 1000V 600A Liquid Cooled NACS Charging Cables; 1000V 700A High Amperage EV Charging Cable Liquid Cooled for CCS2 Charging; 400A GBT Liquid Cooled Charging Cable to meet the needs of high power charging for different markets
   • The ability to maintain a stable temperature also means that the cable's resistance remains more consistent during charging, reducing energy losses due to resistance changes with temperature.
2. Naturally Cooled Cables
   • Their heat dissipation efficiency is limited. They are suitable for relative lower power charging applications. When the charging power exceeds a certain level, the cable temperature can rise rapidly, leading to increased resistance, reduced charging efficiency, and potential damage to the cable insulation and conductors. For example, in a naturally cooled cable, if the charging current exceeds certain limits, the temperature may start to approach critical levels, especially in environments with poor air circulation.

III. Power Carrying Capacity

1. Liquid Cooled Electric Vehicle Charing Cables
   • Can carry higher currents and, consequently, higher power. This is due to their efficient cooling mechanism. They are designed to meet the demands of Hight Power fast-charging stations where quick charging of EVs is essential. The ability to handle high power means that fewer charging stations are needed to serve a given number of EVs, optimizing the charging infrastructure layout.
2. Naturally Cooled Charging Cables
   • Have a lower power carrying capacity. They are more commonly used in home charging units or lower-power public charging points. Their limited power handling ability restricts the charging speed, which may take longer time to fully charge an EV, compared to the much shorter charging times possible with liquid cooled cables in high-power stations. Currently in the world market the highest amperage for naturally/air cooled charging cables is around 350A.  Fiver New New Energy offers 1000V 350A NACS Charging Cable, 1000V 375A EV Charging Cable For CCS2 Charger.

IV. Durability and Lifespan

1. Liquid Cooled Car Charge Cables
   • Tend to have a longer lifespan. The stable temperature control provided by the liquid cooling system reduces the thermal stress on the cable materials. The insulation and conductors are less likely to degrade due to overheating. For example, the insulation material in a liquid cooled cable may maintain its integrity for a longer period compared to a naturally cooled cable under similar usage conditions.
   • However, they have more complex components, such as the coolant circulation system, which may require maintenance and have a potential for leaks or pump failures. But with proper maintenance, their overall durability is high.
2. Naturally Cooled Cables
   • Their lifespan is relatively shorter, especially when used in high-power or continuous charging applications. The repeated exposure to high temperatures due to inefficient heat dissipation can cause the insulation to harden, crack, or lose its insulating properties over time. The conductors may also oxidize more quickly, reducing their conductivity and overall cable performance.

V. Cost

1. Liquid Cooled Charging Cables
   • Have a higher initial cost. The manufacturing process is more complex, requiring the integration of coolant channels, pumps, and a sealed system. The coolant itself also adds to the cost. However, in the long run, their higher efficiency and longer lifespan may offset the initial investment. For large-scale fast-charging networks, the overall cost-benefit ratio can be favorable as they enable faster turnover of EVs and higher utilization of charging stations.
2. Naturally Cooled Cables
   • Have a lower initial cost. They are simpler in design and construction, making them more affordable for home users and small-scale charging installations. But for commercial high-power charging operations, the need for more cables or longer charging times due to their lower power capacity may result in higher operational costs over time.

VI. Environmental Impact

1. Liquid Cooled Cables
   • If using biodegradable coolants, they can have a relatively low environmental impact. However, the manufacturing process and potential coolant leaks need to be carefully managed. The energy consumption of the coolant circulation pump also contributes to the overall environmental footprint, although this is offset by the increased efficiency of the charging process.
2. Air Cooled Charging Cables
   • Have a minimal direct environmental impact related to cooling. But their lower efficiency may lead to longer charging times.

VII. Installation and Maintenance

1. Liquid Cooled Cables
   • Installation requires more expertise and space. The coolant circulation system needs to be properly installed and connected. Regular maintenance is essential to check the coolant level, pump operation, and integrity of the cooling system. Any leaks or malfunctions in the cooling system need to be promptly addressed to ensure proper cable operation.
2. Naturally Cooled Cables
   • Installation is relatively simple and can be done with basic electrical skills. Maintenance mainly involves checking the cable for physical damage and ensuring proper insulation. There is no need to worry about the complexity of a coolant system.