Heat is one of the biggest constraints on EV battery performance. When cells run hotter than intended, they lose usable capacity faster and slip into thermal throttling during fast charging. Most engineers already know this, but what still matters is the choice between air cooling and liquid cooling, and how that choice affects range, charge speed, pack longevity, and warranty exposure.
A modest liquid flow can transfer far more heat than the equivalent volume of air because air’s thermal conductivity is near 0.024 watts per metre kelvin. In comparison, common liquid coolants sit closer to 0.6 watts per metre kelvin. That difference shapes real-world product decisions and explains why markets are shifting so strongly.
Persistence Market Research reported that around 77% of battery cooling plate implementations in 2024 used liquid systems, and the market itself has grown into the billions as OEMs push for tighter thermal control and faster public charging.
This is where the real engineering challenge shows up. Local hot spots inside a pack shorten life, distort cell balancing, reduce charging consistency, and drive up fleet-level and warranty costs. Liquid cooling solves most of that pain by pulling heat away at the source, smoothing temperature differences across cells, and helping the pack recover faster after high-power events.
At Advanced Engineering Services (AES), we convert those thermal advantages into validated, real-world designs. Our teams run CFD and transient thermal simulations to flag hot spots early. We build instrumented prototypes and execute environmental test rigs so you can review temperature maps, transient behaviour, and cooling system performance long before supplier commitments or hardware freezes. If your job involves battery pack design, supplier coordination, or program validation, this is the level of evidence you want at the start of your decision process.
Air has a very low thermal conductivity, typically around 0.024 watts per meter kelvin, which makes it a poor medium for transferring heat. Water, in contrast, has a much higher thermal conductivity of about 0.6 watts per meter kelvin at room temperature, allowing it to move heat far more efficiently than air. In addition to this, water has a significantly higher specific heat capacity and can store roughly four times more heat per kilogram than air, meaning even relatively small liquid flow rates are capable of carrying away large amounts of thermal energy.
From an industry perspective, these thermal advantages are a key reason liquid cooling is widely adopted in advanced systems such as electric vehicle battery packs. The global battery cooling plate market was valued in the low billions in 2023 and is expanding rapidly as EV adoption accelerates and higher charging rates demand more effective thermal management solutions.
AES builds on these fundamentals with strong capabilities in CFD-led thermal design, coupled thermal and structural FEA, environmental and reliability testing, and end-to-end thermal rig build and validation, enabling simulation-driven development from concept through physical verification.
Batteries are chemical devices that work best inside a narrow temperature window. Heat increases internal reactions and speeds up ageing. Cold reduces available power. Uneven heating across a pack creates local stress and uneven capacity fade, which causes headaches for both owners and OEMs.
Keeping the pack uniform means better sustained range, fewer warranty repairs, and more predictable behaviour over the years. That is the engineering goal behind any thermal management program.
Air cooling uses fans and carefully routed ducts to sweep ambient air across modules. It is simple and inexpensive at first glance. It does a reasonable job when the vehicle rarely draws high power, and charging is slow.
But air has limited thermal conductivity and limited heat capacity. To move the same amount of heat, you need a much larger flow and higher fan power. Fans add noise, and they struggle to reach tight gaps or trapped hot spots. In heavy use or during fast charging, the limits quickly appear, and you end up with localised overheating even if the average temperature looks acceptable.
Liquid cooling places a working fluid close to the cells via cold plates or channels. Liquids carry more heat and store more heat per unit volume than air. That lets the system smooth temperature differences and pull heat away from hot spots rapidly.
You can size pumps and radiators to match duty cycles, and the coolant routes can be tuned to give very uniform cell temperatures. For the kinds of fast charging, towing, or continuous high-power EVs customers expect today, liquid cooling offers controlled, repeatable performance.
We at AES use CFD and transient thermal simulations to optimise coolant paths and cold plate geometries so the pack is uniform under realistic driving and charging cycles. That reduces prototype iterations and helps suppliers deliver on performance specs reliably.
You will hear concerns about leaks, electrical safety, packaging, weight, manufacturing, and service. These are valid and solvable with proper systems engineering.
These are real engineering activities that AES lists among its thermal management and testing capabilities. If you need to, we can map each of these items into a development timeline and cost estimate.
Read each line and score it as yes or no, then add up the yes answers.
Scoring Guide
If many answers are yes, consider liquid cooling as the primary path. If most answers are no, then air cooling or a hybrid approach may be acceptable. AES can model both options quickly and provide an evidence-based recommendation.
Air cooling is lighter and has fewer parts, so it stays cheaper when the vehicle only handles mild, everyday driving. Small urban vehicles that rarely fast charge are a logical fit for air cooling.
You can also run hybrid strategies where air handles baseline conditions and liquid kicks in for hot zones. AES will help you test and select the right hybrid balance if that is your chosen route.
AES brings a combined simulation and test approach that reduces risk and development time. Typical engagement steps include:
We have case studies and thermal projects that show this process. If you like connect with our experts and we at AES can produce a short custom report that compares an air-cooled baseline with a liquid-cooled design for your vehicle concept with CFD maps and a test plan.
We at AES can also give you a one-page checklist tailored to your supplier calls and a template RFP for thermal systems. Speak to us for more details.
The right cooling choice is always something you can measure and prove. Liquid cooling gives clear advantages when you expect heavy use, frequent fast charging, or when you want minimal capacity fade over the lifetime of the vehicle. Air cooling keeps things simpler for light-duty use. The smart approach is to model, test, and validate before you commit.
Advanced Engineering Services (AES) can help with that modelling and with building the test rigs that prove a design. We do CFD-led thermal design, transient thermal FEA, instrumentation and environmental testing, and we prepare validation plans that suppliers can execute confidently.
If you would like a tailored comparison report between air and liquid cooling for your EV concept, please contact our thermal management team, and we will assemble a short scope, a sample CFD run, and a test plan you can show stakeholders.
Schedule a discussion with AES to get a free scoping review and a sample CFD thermal map for one module from your pack. Contact AES or check out our thermal management and testing services page to get started.
