Stepping on the threshold of a new year, the demand for the energy storage sector has grown rapidly as a new range of solutions fills the market.
As the popularity of electric vehicles (EVs) flourish in the last few years, rechargeable batteries have become the topic of discussion for research as well as innovation for many automotive original equipment manufacturers (OEMs).
OEMs are now aggressively taking their stance on electrifying their fleets, adding EVs and hybrid-electric vehicles (HEVs) to their products and some are even promising to go fully electric in just a few years.
Because of this, many engineers who worked on conventional vehicles are now asked to switch their attention to EVs and HEVs.
However, this switching comes with its own set of challenges as battery-operated vehicles need a robust thermal management system or Battery Cooling System in EVs to dissipate the high heat generated during its operation.
Despite undergoing a lot of advancements, electric vehicle batteries require an effective battery safety system that enables them to deliver more power and need less frequent charges.
Nevertheless, before mentioning the types of Battery Cooling System in EVs and their market, let’s check out the significance of Battery Cooling System in EVs.
Why is Battery Cooling System in EVs so Relevant?
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Before understanding the relevance of a Battery Cooling System in EVs, everyone should be familiar with the known fact that in the case of electric cars, discharging the battery can generate heat so the more rapidly the battery discharges, the more heat it will generate.
Since, batteries operate on the principle of a voltage differential, at high temperatures the electrons inside become excited which in turn decreases the difference in voltage between the two sides of the battery.
As batteries are only manufactured to work under certain temperature extremes, they will stop working if there is no Battery Cooling System in EVs to keep them within a working range.
Battery Cooling System in EVs should be able to keep the battery pack in the temperature range of around 20-40 degrees Celsius and keep the temperature difference within the battery pack to a minimum.
So, if there is a large thermal difference internally, it can lead to varying discharge rates and charges, and will cause potential thermal instability and will affect the battery performance.
Categorizing Battery Cooling System in EVs
Generally, Battery Cooling System in EVs regulates the temperature of the battery pack as the thermal management in electric vehicles uses cooling loops that contain liquid coolants like ethylene glycol.
An electric pump typically circulates the coolant through the batteries and the Battery Cooling System in EVs can be categorized as an air-based cooling system, liquid-based cooling system as well as Submersion cooling system for EVs.
However, the submersion or immersion cooling system is still in the development phase and the air-cooling system is found to have some drawbacks, thus failing its purpose in the long run.
For the majority of reasons, liquid cooling systems for EVs are preferred due to their effectiveness and better performance criteria.
Passive Liquid Cooling Systems
In this type of liquid cooling system, the cooling power majorly depends on the temperature difference between the ambient air and the battery. Hence, the cooling performance can be improved by connecting fans behind radiators.
Active Liquid Cooling Systems
On the other hand, an active liquid cooling system is effective when the ambient temperature is higher than the battery temperature or when the temperature difference is too small.
As the active liquid cooling system consists of two loops, the primary loop is very similar to the passive liquid cooling system whereas the secondary loop is in the air conditioning loop. Thus, it consists of two heat exchangers working as evaporators and condensers, respectively.
Battery Cooling System in EVs – Current Market Scenario
Typically for Battery Cooling System in EVs, liquid-cooling systems prefer piped cooling as the best method as it is found to be better at driving hot air away from the batteries in comparison to air-cooling.
Despite the flip side of having a limited liquid coolant-carrying capacity, liquid glycol has found acceptance by automakers like Tesla and GM.
Giving a clearer perspective, there are around 7,000 cells in a Tesla battery pack which uses a metal tube arranged in a serpentine pattern in a series arrangement. In contrast, General Motors uses aluminum, in a parallel arrangement. While Porsche, in its Boxter E, is known to be employing a liquid-filled cooling plate from the traction battery.
A complete contrast in Battery Cooling System in EVs can be seen in India, where a startup company like Matter has claimed to develop its unique refrigerant system aimed at cooling overheated batteries. According to the company’s announcement, Matter has developed a highly integrated battery pack that will meet the needs of the electric two-wheeler industry.
Another Indian conglomerate, Tata Motors employs its ziptron technology in its Tata ACE EV where they have deployed liquid-cooled battery packs and have been able to back it up with an extensive warranty.