Liquid-cooling technology has been around in the automotive world for a while, even in the EV sphere, using a liquid to cool a battery is not new. However, this week, Tesla released their patented liquid-cooled charger connection to the world and whenever a pioneer such as Tesla brings out new technology, it soon gains traction among the rest of the community – manufacturers and automakers alike.
It is assumed the technology will be showcased in the company’s new EV charger network; the V3 supercharger, a successor to the V2 supercharger, which already includes a liquid-cooled cable, therefore, we thought we would provide a breakdown of what the patent included and how liquid-cooling may affect chargers in the future.
Figure 1: Tesla V3 Supercharger.
First of all, it is important to understand that charging infrastructure experiences a trade-off between the amount of energy it can draw from the mains and discharge to the EV in a given time and the temperature (and so safety) of the apparatus involved.
Current chargers aren’t really cooled, if they are, they are air-cooled, sometimes this air is accelerated using fans but up-till now targeted heat dissipation has not really been necessary because chargers have not been fast enough to reach the limitations of their components.
However, as the demand and emphasis on EV adoption grows, a significant barrier preventing the switch from ICEs to EV is their ability to charge in a time frame as convenient to that of their fossil-fuelled counterparts. Therefore, there is a growing need for faster and faster-charging options.
To achieve that you need a charger capable of dealing with high voltage, voltage creates heat, so you need a charger capable of dealing with a lot of heat. Tesla’s liquid-cooled charger works by passing liquid over temperature-sensitive components in the charging mechanism; the cable and the connector which are housed in a thermally conducting material acting as a medium, improving the efficiency of the heat exchange system. With less heat affecting vital components, the chargers are not only capable of charging faster but they are significantly safer.
Figure 2: Diagrams of Tesla’s liquid-cooled charger connection patent.
What does this cooling actually mean in numbers then?
Well, Tesla claims during a 5-minute charge from their V3 charger, a vehicle can obtain up to 75 miles of range. Similar quotes have been published by ITT Cannon for their liquid-cooled DC High Power Charging (HPC) system, offering a 60-mile range from just 3 minutes of charging. These benefits are obviously dependent upon the age of the vehicle; its hardware capabilities and battery limitations so if you have one of the first generations of EVs you won’t notice a great deal of difference with liquid-cooled chargers like you didn’t with the introduction of rapid chargers. Liquid-cooling could be considered the next generation of charging technology judging by the kW output performance as seen in figure 3.
The configuration of components, type and movement of the liquid-cooling agent and the material used for thermally conducting heat from the cables to the liquid are all areas for further research and development. Targeted cooling could determine an array of different characteristics for the next generation of EV chargers, potentially changing their size, their weight, the type of vehicles they charge, their durability and the capabilities of the EV charging infrastructure network in managing a growing demand.
Liquid-cooling holds great potential in the race for faster EV charging – we here at Solisco are very excited to see what the future brings!
Author: Ajeet Panesar, Sustainable Infrastructure Specialist, Solisco