<img src="https://spectrum.ieee.org/media-library/black-cylinder-stamped-with-the-word-hydrohertz.jpg?id=62595319&width=1245&height=700&coordinates=0%2C62%2C0%2C63"/> Fast, <a href="https://spectrum.ieee.org/tag/fast-charging" target="_self">direct-current charging</a> 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 <a href="https://spectrum.ieee.org/vanadium-batteries" target="_blank">EV battery packs</a> as the pack is charged. <a href="https://www.hydrohertz.com/" rel="noopener noreferrer" target="_blank">Hydrohertz</a>, 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.<h2>A Smarter Way to Move Coolant</h2>Hydrohertz calls its solution <a href="https://www.hydrohertz.com/industries/show/the-dectravalve" target="_blank">Dectravalve</a>. 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 <a href="https://www.trumonytechs.com/what-is-a-battery-cold-plate/" target="_blank">cold plates</a>, 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 <a href="https://www.che.psu.edu/department/directory-detail-g.aspx?q=CXW31" target="_blank">Chao-Yang Wang</a>, a mechanical and chemical engineering professor at <a href="https://www.che.psu.edu/index.aspx" target="_blank">Pennsylvania State University</a> 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 MichiganHydrohertz 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 <a href="https://uk.linkedin.com/in/martyn-talbot-bb06a9100" target="_blank">Martyn Talbot</a> 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 <a href="https://me.engin.umich.edu/people/faculty/anna-stefanopoulou/" target="_blank">Anna Stefanopoulou</a>, a professor of mechanical engineering at the <a href="https://umich.edu/" target="_blank">University of Michigan</a> 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 <a href="https://uk.linkedin.com/in/martyn-talbot-bb06a9100" target="_blank">Talbot</a>.<h2>Charge Times Can Be Cut By 60 Percent</h2>In early 2025, the Dectravalve underwent bench testing conducted by the <a href="https://warwick.ac.uk/fac/sci/wmg/" target="_blank">Warwick Manufacturing Group</a> (WMG), a multidisciplinary research center at the <a href="https://warwick.ac.uk/" target="_blank">University of Warwick</a>, 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 <a href="https://www.sciencedirect.com/science/article/abs/pii/S0360128521000514" target="_blank">lithium plating</a> 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. <h2> When Batteries Keep Cool, They Live Longer</h2>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.

قامت شركة Hydrohertz، وهي شركة ناشئة بريطانية أسسها مهندسون سابقون في رياضة السيارات والإلكترونيات، بتطوير صمام يمكن أن يقلل بشكل كبير من أوقات الشحن السريع للمركبات الكهربائية (EV) من خلال معالجة مشكلات التبريد في حزم بطاريات المركبات الكهربائية. تهدف التكنولوجيا إلى توجيه سائل التبريد بدقة إلى المكان الذي يحتاجه أثناء الشحن، مما قد يقلل من الوقت اللازم لشحن المركبة الكهربائية من 20 إلى 80 بالمئة، والذي يستغرق حاليًا حوالي 20 دقيقة.

Hydrohertz, una startup británica fundada por exingenieros de automovilismo y electrónica de potencia, ha desarrollado una válvula que podría reducir significativamente los tiempos de carga rápida de los vehículos eléctricos (VE) al abordar los problemas de refrigeración en los paquetes de baterías de los VE. La tecnología tiene como objetivo dirigir el refrigerante líquido exactamente donde se necesita durante la carga, lo que podría reducir a la mitad el tiempo necesario para cargar un VE del 20 al 80 %, que actualmente toma alrededor de 20 minutos.

Hydrohertz, une startup britannique fondée par d'anciens ingénieurs en sport automobile et en électronique de puissance, a développé une vanne qui pourrait réduire considérablement les temps de charge rapide des véhicules électriques (VE) en s'attaquant aux problèmes de refroidissement dans les packs de batteries des VE. La technologie vise à diriger le liquide de refroidissement précisément là où il est nécessaire pendant la charge, ce qui pourrait réduire de moitié le temps nécessaire pour charger un VE de 20 à 80 %, actuellement d'environ 20 minutes.

Hydrohertz, a British startup founded by former motorsport and power-electronics engineers, has developed a valve that could significantly reduce electric vehicle (EV) fast-charging times by addressing cooling issues in EV battery packs. The technology aims to direct liquid coolant precisely where it is needed during charging, potentially halving the time it takes to charge an EV from 20 to 80 percent, which currently takes about 20 minutes.

This Valve Could Halve EV Fast-Charge Times

<img src="https://spectrum.ieee.org/media-library/a-square-chip-with-black-and-gold-components-leans-against-a-sugar-cube.jpg?id=62599760&width=1245&height=700&coordinates=0%2C187%2C0%2C188"/> For decades, <a href="https://spectrum.ieee.org/optical-atomic-clocks" target="_self">atomic clocks</a> have provided the most stable means of timekeeping. They <a href="https://spectrum.ieee.org/device-that-revolutionized-timekeeping-receives-an-ieee-milestone" target="_self">measure time</a> by oscillating in step with the resonant frequency of atoms, a method so accurate that it serves as the basis for the definition of a second. Now, a new challenger has emerged in the timekeeping arena. Researchers recently developed a tiny, MEMS-based clock that makes use of silicon doping to gain record stability. After running for 8 hours, the clock deviated only by 102 nanoseconds, approaching the standard of atomic clocks while both requiring less physical space and less power to run. Doing so has been a challenge in the past because of the chaos that even slight temperature variations can introduce into timekeeping.The group <a href="https://iedm25.mapyourshow.com/8_0/sessions/session-details.cfm?scheduleid=80" rel="noopener noreferrer" target="_blank">presented</a> their new clock at the <a href="https://www.ieee-iedm.org/" rel="noopener noreferrer" target="_blank">71st Annual IEEE International Electron Devices Meeting</a> last week.<h2>Saving Space and Power</h2>The MEMS clock is built from a few tightly connected parts, all integrated on a chip smaller than the face of a sugar cube. At its center, a silicon plate topped with a <a href="https://www.sciencedirect.com/topics/engineering/piezoelectric-effect" rel="noopener noreferrer" target="_blank">piezoelectric</a> film vibrates at its natural frequencies, while nearby electronic circuitry measures those vibrations. A tiny, built-in heater gently keeps the whole structure at an optimal temperature. Because the resonator, electronics, and heater are all close together, they can work as a coordinated system: The resonator creates the timing signal, the electronics monitor and adjust it, and the heater prevents temperature swings from causing drift. This clock is unique in a few ways, explains project advisor and University of Michigan MEMS engineer <a href="https://phonon.engin.umich.edu/" rel="noopener noreferrer" target="_blank">Roozbeh Tabrizian</a>. For one, the resonator is “extremely stable amid variations in environment,” he says. “You could actually change the temperature from -40 °C all the way to 85 °C and you essentially don’t see any change in the frequency.”The resonator is so stable because the silicon from which it’s crafted has been <a href="https://www.sciencedirect.com/topics/engineering/semiconductor-doping" rel="noopener noreferrer" target="_blank">doped</a> with phosphorus, Tabrizian says. When a material is doped, impurities are added into it, typically to change its conductive properties. Here, though, the group used doping specifically to stabilize mechanical properties. “We’re controlling the mechanics in a very tight way so that the elasticity of the material does not change upon temperature variations,” he says. Some other materials, like the commonly used timing-crystal <a href="https://spectrum.ieee.org/diy-ocxo-quartz-clock" target="_self">quartz</a>, can also be doped for robustness. But “you cannot miniaturize [quartz] and you have a lot of limitations in terms of packaging,” Tabrizian explains. “Semiconductor manufacturing benefits from size miniaturization,” so it is an obvious choice for next-generation clocks.The doping also allows the electronics to actively tune out any small drifts in frequency over long periods. This attribute is “the most distinctive aspect of our device’s physics compared to previous MEMS clocks,” Tabrizian says. By making the silicon conductive, the doping lets the electronics subtly adjust how strongly the device is mechanically driven, which counteracts slow shifts in frequency.This system is also unique in its integration of autonomous temperature sensing and adjustment, says <a href="https://ece.engin.umich.edu/people/directory/phd-students/" rel="noopener noreferrer" target="_blank">Banafsheh Jabbari</a>, a graduate student at the University of Michigan who led the project. “This clock resonator is operating in two modes [or resonant frequencies], essentially. The main mode of the clock is very stable and we use it as the [time] reference. The other one is the temperature sensor.” The latter acts like an internal thermometer, helping the electronics automatically detect temperature shifts and adjust both the heater and the main timing mode itself. This built-in self-correction helps the clock maintain steady time even as the surrounding environment changes.These features mean that it’s the first MEMS clock to run for 8 hours and only deviate by 102-billionths of a second. Linearly scaled up to a week of operation, that equates to just over 2 microseconds of drift. That’s worse than the top-of-the-line laboratory atomic clocks by a few orders of magnitude, but it rivals the stability of miniaturized atomic clocks. What’s more, the MEMS clock has a significant space and power savings advantage over its atomic competition. The more isolated from their environments and the more power they use, the more precisely atomic clocks can probe the oscillations of atoms, Tabrizian explains, so they’re typically the size of a cabinet and draw a lot of power. Even chip-scale atomic clocks are 10 to 100 times as large as the MEMS clock, he says. And, “more importantly,” this new clock requires 1/10th to 1/20th the power of the mini atomic clocks.<h2>Timekeeping for Next-Gen Tech</h2>Jabbari’s work came out of a <a href="https://www.darpa.mil/research/programs/h6" rel="noopener noreferrer" target="_blank">DARPA project</a> with the goal of making a clock that could operate for a week and deviate by only 1 µs, so there’s still more to be done. One challenge the team faces is how the doped silicon will behave over longer operating periods, like a week. “You see some diffusion and some changes in the material,” Tabrizian says, but only time will tell how well the silicon will hold up.It’s important to both researchers that they continue their efforts because of the wide-ranging applications they foresee for a small, power-efficient MEMS-based clock. “Essentially all modern technology that we have needs some sort of synchronization,” Jabbari says, and she thinks the clock could fill gaps in time synchronization that currently exist.For situations in which technology has robust access to <a href="https://spectrum.ieee.org/gladys-west-hidden-figure-gps" target="_self">GPS</a> satellites, there’s no problem to solve, she says. But in more extreme scenarios, like space exploration and underwater missions, navigation technology is forced to rely on internal timekeeping—which must be extremely bulky and power hungry to be accurate. A MEMS clock could be a small and less power-intensive replacement.There are also more day-to-day applications, Tabrizian says. In the future, when more information will need to be delivered faster to each phone (or whatever devices we’ll be using in 50 years), accurate timing will become crucial for data-packet delivery. “And, of course, you cannot put a large atomic clock in your phone. You cannot consume that much power,” he says, so a MEMS clock could be the answer.Even with promising applications, it could be a tough road ahead for this project because of existing competition. <a href="https://www.sitime.com/products?utm_source=google&utm_medium=cpc&utm_campaign=summer_sale_2023&utm_term=sitime&utm_source=google&utm_medium=cpc&utm_campaign=20246058643&utm_term=sitime&_bt=660933302525&_bm=b&_bn=g&gad_source=1&gad_campaignid=20246058643&gbraid=0AAAAADra00z9oxkYNgEzq6VHLuDMCIrnL&gclid=CjwKCAiA0eTJBhBaEiwA-Pa-haMEG8N_ry8vF9fv1iR0IIdWbr-HpWjQxJ5Ro6Oe0qN8GmAzAg1kPxoCtJIQAvD_BwE" rel="noopener noreferrer" target="_blank">SiTime</a>, a company already producing <a href="https://spectrum.ieee.org/mems-time" target="_self">MEMS clocks</a>, is even now <a href="https://www.reuters.com/business/sitime-releases-new-chip-aimed-wearable-gadgets-2025-09-17/" target="_blank">integrating</a> its chips in Apple and Nvidia devices.But Tabrizian is confident about his team’s capabilities. “Companies like SiTime put a lot of emphasis on system design,” thus increasing system complexity, he says. “Our solution, on the other hand, is entirely physics based, looking into the very intricate, very fundamental physics of a semiconductor. We’re trying to get around the need for a complex system by making the resonator 100 times more accurate than the SiTime resonator.”

طور الباحثون ساعة تعتمد على تقنية MEMS تستخدم تشبع السيليكون لتحقيق استقرار ملحوظ، حيث انحرفت فقط بمقدار 102 نانوثانية بعد 8 ساعات من التشغيل. تتحدى هذه الابتكارات هيمنة الساعات الذرية في دقة قياس الوقت.

Investigadores han desarrollado un reloj basado en MEMS que utiliza el dopaje de silicio para lograr una estabilidad notable, desviándose solo 102 nanosegundos después de 8 horas de funcionamiento. Esta innovación desafía el dominio de larga data de los relojes atómicos en precisión temporal.

Des chercheurs ont développé une horloge basée sur la technologie MEMS qui utilise le dopage au silicium pour atteindre une stabilité remarquable, ne déviant que de 102 nanosecondes après 8 heures de fonctionnement. Cette innovation remet en question la domination de longue date des horloges atomiques en matière de précision.

Researchers have developed a MEMS-based clock that utilizes silicon doping to achieve remarkable stability, deviating only 102 nanoseconds after 8 hours of operation. This innovation challenges the long-standing dominance of atomic clocks in timekeeping accuracy.

This Valve Could Halve EV Fast-Charge Times

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