Fast, direct-current charging can charge an EV’s battery from about 20 percent to 80 percent in 20 minutes. That’s not bad, but it’s still about six times as long as it takes to fill the tank of an ordinary petrol-powered vehicle.

One of the major bottlenecks to even faster charging is cooling, specifically uneven cooling inside big EV battery packs as the pack is charged. Hydrohertz, a British startup launched by former motorsport and power-electronics engineers, says it has a solution: fire liquid coolant exactly where it’s needed during charging. Its solution, announced in November, is a rotary coolant router that fires coolant exactly where temperatures spike, and within milliseconds—far faster than any single-loop system can react. In laboratory tests, this cooling tech allowed an EV battery to safely charge in less than half the time than was possible with conventional cooling architecture.

A Smarter Way to Move Coolant

Hydrohertz calls its solution Dectravalve. It looks like a simple manifold, but it contains two concentric cylinders and a stepper motor to direct coolant to as many as four zones within the battery pack. It’s installed in between the pack’s cold plates, which are designed to efficiently remove heat from the battery cells through physical contact, and the main coolant supply loop, replacing a tangle of valves, brackets, sensors, and hoses.

To keep costs low, Hydrohertz designed Dectravalve to be produced with off-the-shelf materials, and seals, as well as dimensional tolerances that can be met with the fabrication tools used by many major parts suppliers. Keeping things simple and comparatively cheap could improve Dectravalve’s chances of catching on with automakers and suppliers notorious for frugality. “Thermal management is trending toward simplicity and ultralow cost,” says Chao-Yang Wang, a mechanical and chemical engineering professor at Pennsylvania State University whose research areas include dealing with issues related to internal fluids in batteries and fuel cells. Automakers would prefer passive cooling, he notes—but not if it slows fast charging. So, at least for now, Intelligent control is essential.

“If Dectravalve works as advertised, I’d expect to see a roughly 20 percent improvement in battery longevity, which is a lot.”–Anna Stefanopoulou, University of Michigan

Hydrohertz built Dectravalve to work with ordinary water-glycol, otherwise known as antifreeze, keeping integration simple. Using generic antifreeze avoids a step in the validation process where a supplier or EV manufacturer would otherwise have to establish whether some special formulation is compatible with the rest of the cooling system and doesn’t cause unforeseen complications. And because one Dectravalve can replace the multiple valves and plumbing assemblies of a conventional cooling system, it lowers the parts count, reduces leak points, and cuts warranty risk, Hydrohertz founder and CTO Martyn Talbot claims. The tighter thermal control also lets automakers shrink oversize pumps, hoses, and heat exchangers, improving both cost and vehicle packaging.

The valve reads battery-pack temperatures several times per second and shifts coolant flow instantly. If a high-load event—like a fast charge—is coming, it prepositions itself so more coolant is apportioned to known hot spots before the temperature rises in them.

Multizone control can also speed warm-up to prevent the battery degradation that comes from charging at frigid temperatures. “You can send warming fluid to heat half the pack fast so it can safely start taking load,” says Anna Stefanopoulou, a professor of mechanical engineering at the University of Michigan who specializes in control systems, energy, and transportation technologies. That half can begin accepting load, while the system begins warming the rest of the pack more gradually, she explains. But Dectravalve’s main function remains cooling fast-heating troublesome cells so they don’t slow charging.

Quick response to temperature changes inside the battery doesn’t increase the cooling capacity, but it leverages existing hardware far more efficiently. “Control the coolant with more precision and you get more performance for free,” says Talbot.

Charge Times Can Be Cut By 60 Percent

In early 2025, the Dectravalve underwent bench testing conducted by the Warwick Manufacturing Group (WMG), a multidisciplinary research center at the University of Warwick, in Coventry, England, that works with transport companies to improve the manufacturability of battery systems and other technologies. WMG compared Dectravalve’s cooling performance with that of a conventional single-loop cooling system using the same 100-kilowatt-hour battery pack. During fast-charge trials from 10 percent to 80 percent, Dectravalve held peak cell temperature below 44.5 °C and kept cell-to-cell temperature variation to just below 3 °C without intervention from the battery management system. Similar thermal performance for the single-loop system was made possible only by dialing back the amount of power the battery would accept—the very tapering that keeps fast charging from being on par with gasoline fill-ups.

Keeping the cell temperatures below 50 °C was key, because above that temperature lithium plating begins. The battery suffers irreversible damage when lithium starts coating the surface of the anode—the part of the battery where electrical charge is stored during charging—instead of filling its internal network of pores the way water does when it’s absorbed by a sponge. Plating greatly diminishes the battery’s charge-storage capacity. Letting the battery get too hot can also cause the electrolyte to break down. The result is inhibited flow of ions between the electrodes. And reduced flow within the battery means reduced flow in the external circuit, which powers the vehicle’s motors.

Because the Dectravalve kept temperatures low and uniform—and the battery management system didn’t need to play energy traffic cop and slow charging to a crawl to avoid overheating—charging time was cut by roughly 60 percent. With Dectravalve, the battery reached 80 percent state of charge in between 10 and 13 minutes, versus 30 minutes with the single-cooling-loop setup, according to Hydrohertz.

When Batteries Keep Cool, They Live Longer

Using Warwick’s temperature data, Hydrohertz applied standard degradation models and found that cooler, more uniform packs last longer. Stefanopoulou estimates that if Dectravalve works as claimed, it could boost battery life by roughly 20 percent. “That’s a lot,” she says.

Still, it could be years before the system shows up on new EVs, if ever. Automakers will need years of cycle testing, crash trials, and cost studies before signing off on a new coolant architecture. Hydrohertz says several EV makers and battery suppliers have begun validation programs, and CTO Talbot expects licensing deals to ramp up as results come in. But even in a best-case scenario, Dectravalve won’t be keeping production-model EV batteries cool for at least three model years.

A prototyping problem is emerging in today’s efforts to electrify everything. What works as a lab-bench mockup breaks in reality. Harnessing and safely storing energy at grid scale and in cars, trucks, and planes is a very hard problem that simplified models sometimes can’t touch.

“In electrification, at its core, you have this combination of electromagnetic effects, heat transfer, and structural mechanics in a complicated interplay,” says Bjorn Sjodin, senior vice president of product management at the Stockholm-based software company COMSOL.

COMSOL is an engineering R&D software company that seeks to simulate not just a single phenomenon—for instance, the electromagnetic behavior of a circuit—but rather all the pertinent physics that needs to be simulated for developing new technologies in real-world operating conditions.

Engineers and developers gathered in Burlington, Mass. on 8 to 10 October for COMSOL’s annual Boston conference, where they discussed engineering simulations via multiple simultaneous physics packages. And multiphysics modeling, as the emerging field is called, has emerged as a component of electrification R&D that is becoming more than just nice to have.

“Sometimes, I think some people still see simulation as a fancy R&D thing,” says Niloofar Kamyab, a chemical engineer and applications manager at COMSOL. “Because they see it as a replacement for experiments. But no, experiments still need to be done, though experiments can be done in a more optimized and effective way.”

Can Multiphysics Scale Electrification?

Multiphysics, Kamyab says, can sometimes be only half the game.

“I think when it comes to batteries, there is another attraction when it comes to simulation,” she says. “It’s multiscale—how batteries can be studied across different scales. You can get in-depth analysis that, if not very hard, I would say is impossible to do experimentally.”

In part, this is because batteries reveal complicated behaviors (and runaway reactions) at the cell level but also in unpredictable new ways at the battery-pack level as well.

“Most of the people who do simulations of battery packs—thermal management is one of their primary concerns,” Kamyab says. “You do this simulation so you know how to avoid it. You recreate a cell that is malfunctioning.” She adds that multiphysics simulation of thermal runaway enables battery engineers to safely test how each design behaves in even the most extreme conditions—in order to stop any battery problems or fires before they could happen.

Wireless charging systems are another area of electrification, with their own thermal challenges. “At higher power levels, localized heating of the coil changes its conductivity,” says Nirmal Paudel, a lead engineer at Veryst Engineering, a consulting firm based in Needham, Mass. And that, he notes, in turn can change the entire circuit as well as the design and performance of all the elements that surround it.

Electric motors and power converters require similar simulation savvy. According to electrical engineer and COMSOL senior application engineer Vignesh Gurusamy, older ways of developing these age-old electrical workhorse technologies are proving less useful today. “The recent surge in electrification across diverse applications demands a more holistic approach as it enables the development of new optimal designs,” Gurusamy says.

And freight transportation: “For trucks, people are investigating, Should we use batteries? Should we use fuel cells?” Sjodin says. “Fuel cells are very multiphysics friendly—fluid flow, heat transfer, chemical reactions, and electrochemical reactions.”

Lastly, there’s the electric grid itself. “The grid is designed for a continuous supply of power,” Sjodin says. “So when you have power sources [like wind and solar] shutting off and on all the time, you have completely new problems.”

Multiphysics in Battery and Electric-Motor Design

Taking such an all-in approach to engineering simulations can yield unanticipated upsides as well, says Kamyab. Berlin-based automotive engineering company IAV, for example, is developing power-train systems that integrate multiple battery formats and chemistries in a single pack. “Sodium ion cannot give you the energy that lithium ion can give,” Kamyab says. “So they came up with a blend of chemistries, to get the benefits of each, and then designed a thermal management that matches all the chemistries.”

Jakob Hilgert, who works as a technical consultant at IAV, recently contributed to a COMSOL industry case study. In it, Hilgert described the design of a dual-chemistry battery pack that combines sodium-ion cells with a more costly lithium solid-state battery.

Hilgert says that using multiphysics simulation enabled the IAV team to play the two chemistries’ different properties off of each other. “If we have some cells that can operate at high temperatures and some cells that can operate at low temperatures, it is beneficial to take the exhaust heat of the higher-running cells to heat up the lower-running cells, and vice versa,” Hilgert said. “That’s why we came up with a cooling system that shifts the energy from cells that want to be in a cooler state to cells that want to be in a hotter state.”

According to Sjodin, IAV is part of a larger trend in a range of industries that are impacted by the electrification of everything. “Algorithmic improvements and hardware improvements multiply together,” he says. “That’s the future of multiphysics simulation. It will allow you to simulate larger and larger, more realistic systems.”

According to COMSOL’s Gurusamy, GPU accelerators and surrogate models allow for bigger jumps in electric-motor capabilities and efficiencies. Even seemingly simple components like the windings of copper wire in a motor core (called stators) provide parameters that multiphysics can optimize.

“A primary frontier in electric-motor development is pushing power density and efficiency to new heights, with thermal management emerging as a key challenge,” Gurusamy says. “Multiphysics models that couple electromagnetic and thermal simulations…incorporate temperature-dependent behavior in stator windings and magnetic materials.”

Simulation is also changing the wireless charging world, Paudel says. “Traditional design cycles tweak coil geometry,” he says. “Today, integrated multiphysics platforms enable exploration of new charging architectures,” including flexible charging textiles and smart surfaces that adapt in real time.

And batteries, according to Kamyab, are continuing a push toward higher power densities and lower prices. Which is changing not just the industries where batteries are already used, like consumer electronics and EVs. Higher-capacity batteries are also driving new industries like electric vertical take-off and landing aircraft (eVTOLs).

“The reason that many ideas that we had 30 years ago are becoming a reality is now we have the batteries to power them,” Kamyab says. “That was the bottleneck for many years.... And as we continue to push battery technology forward, who knows what new technologies and applications we’re making possible next.”