The “DectraValve” technology proposed by the British startup Hydrohertz opens the door to a significant reduction in battery pack charging times thanks to more efficient management of heat flows within the accumulator sections
Thermal management of batteries is one of the central challenges in the engineering of electric vehicles. It has a decisive influence on charging performance, safety and the service life of the cells. Lithium-ion batteries, whether of the LFP type (lithium iron phosphate) or NCM type (nickel, cobalt and manganese oxide), generate heat both during charging phases and during use due to internal resistance, ongoing electrochemical reactions between elements and polarization phenomena.
The higher the power used to recharge the battery, the greater the heat production. This phenomenon becomes particularly critical during high-power fast charging, with values that can exceed 350 kilowatts, because current flows of hundreds of amperes lead to a rapid increase in cell temperature, which instead must remain within relatively low values.
It is enough to say that if the temperature exceeds roughly 50 degrees Celsius, the charging management systems must inevitably reduce power to avoid harmful phenomena. Among these is lithium plating on the surface of the electrodes, which can permanently degrade cell performance and reduce their service life, as well as the formation of dendrites inside the cells.
Another complication is that the temperature of the cells within the same battery pack is not uniform and can vary significantly in relation to reliability thresholds. Between individual groups of cells the variation can reach as much as 10–15 degrees Celsius, forcing the system to operate under conservative conditions and extending charging times.
Precisely to address these issues, the British startup Hydrohertz has developed a battery thermal control technology called “DectraValve”, which stands out for its multi-zone system management that overcomes the limits of traditional cooling systems. These systems tend to treat the entire pack as a single thermal volume, circulating coolant or air through fixed channels that remove heat in a homogeneous but non-targeted way.
As a result, entire groups of cells can radiate heat unevenly, creating warmer areas known as “hot spots”. When such thermal anomalies develop, the electronic management system must limit charging current to protect the cells, thereby slowing down the charging process for the entire battery pack.
The “DectraValve” technology solves this problem by introducing a patented electronically controlled valve capable of creating and independently controlling multiple thermal “zones” within the same battery pack, directing cooling fluids precisely where needed without mixing with adjacent zones.
This precise control does not require a complex network of multiple valves or bulky piping. Instead, it starts from a single coolant inlet that is then distributed among four or more areas depending on the system architecture through one or more valves, maximizing flow toward the areas under the greatest thermal stress.
This makes it possible to keep temperatures between cells uniform and stable, with differences of less than three degrees Celsius even under ultra-high-power charging.
This precision in control has significant performance implications. During tests conducted on a 100 kilowatt-hour LFP battery pack with fast charging up to 350 kilowatts, the maximum temperature of any cell remained below 44.5 degrees, well below the threshold where degradation risks begin, while the overall temperature difference across the pack was kept just above two and a half degrees.
The direct benefit of this thermal control is the ability to maintain high charging power for longer periods without the system automatically reducing current. In independent tests, this resulted in a reduction in charging time from ten to eighty percent.
From an engineering standpoint, this means the system can sustain very high power densities without thermal limits becoming the restricting factor, allowing full use of the capabilities of high-power chargers available in the most modern infrastructure.
A particularly interesting aspect of the Hydrohertz solution is its chemical neutrality. The thermal control system is not tied to a specific cell chemistry but can be applied to any type of battery, including future solid-state versions.
Moreover, the system is compatible with more than 90 percent of existing electric platforms and can potentially be retrofitted even on vehicles already on the market. This approach allows vehicle manufacturers to obtain a performance boost without having to redesign battery packs from scratch.
From the standpoint of energy efficiency, keeping all cells at their optimal temperature also reduces internal losses associated with heat conduction and with the inevitable current reduction performed by the battery management system (BMS), positively influencing the vehicle’s effective driving range, which in some real-world conditions can increase by up to about 10 percent compared with traditional packs without zonal control.
In terms of safety, more precise temperature control mitigates some of the main risks associated with thermal stress. Cases of thermal runaway, the uncontrolled propagation of heat from an overheated cell to adjacent ones, are less likely when thermal dispersion within the pack is reduced and local peaks are contained.
Title: Tecnology Hydrohertz DectreValve: turbocharging charging
Translation with ChatGPT
