Ultra-fast charging batteries

Over the past decade, average EV battery pack energy density (Wh/kg) has increased by around 60%, while prices have fallen by roughly 75%. Moreover, in 2023, battery-related patents accounted for 40% of all energy-sector patents, suggesting that more developments are still to come. At the same time, new power‑electronics materials, battery cell technologies and battery pack architectures are enabling more efficient, higher‑voltage – and therefore faster – charging systems.

The battery pack voltage plays a key role in enabling faster charging, as the power that can be delivered to a vehicle is constrained by the maximum current that can flow through the charging station and vehicle charging system. At a given current, delivered power is proportional to the battery pack voltage – if the system power limits allow, doubling the voltage (e.g. from 400 V to 800 V) doubles the charging power. Alternatively, for a given power level, doubling the voltage halves the required current, and since resistive heat losses are proportional to the square of the current, it reduces them by 75%.

An electric vehicle battery pack is composed of hundreds or thousands1 of battery cells, each typically operating at a voltage of around 3-4 volts (V). These cells can be connected in series or in parallel, with series configurations increasing the overall pack voltage to the required level. Most battery electric cars on the market today operate with battery systems of around 400 V, which has long been considered a suitable compromise between charging performance and battery pack complexity, cost and reliability. However, the increasing availability of ultra‑fast charging infrastructure, alongside improvements in battery and vehicle technologies, as well as consumer concerns related to range and charging times, is accelerating the shift towards higher‑voltage electric vehicle systems.

Raising battery pack voltage to enable faster charging not only requires a shift from conventional power‑electronics materials, typically silicon, towards alternative semiconductors such as gallium nitride (GaN) and silicon carbide (SiC), but also reduces tolerance to battery cell‑level defects. This requires even tighter control of cell quality to mitigate risks associated with minor manufacturing defects. Improvements in battery design, manufacturing quality and underlying technologies over recent years have therefore been critical in enabling the current shift towards higher‑voltage systems.

Higher voltage battery packs require lower electrical current and reduce heat losses, which benefits the charging system and associated cabling, but not the battery itself. As the voltage of individual battery cells is fixed and does not depend on the battery pack configuration, the current applied at the cell level during operation depends on the charging power. Ultimately, faster charging is therefore constrained by the ability of battery cells to safely withstand higher currents, which is typically characterised through the “C-rate” 2, and by how efficiently these cells can be cooled down during charging to ensure safety.

The latest battery technologies – such as the BYD blade battery or CATL Shenxing – can reach up to 10C or 12C in the early phases of charging, compared to just over 2C when an average battery electric car is charged at 150 kW. When combined with high‑voltage battery packs (above 800 V) and charging systems capable of handling very high currents, these advances have enabled megawatt‑scale charging for passenger electric cars, first introduced by BYD in 2025. This enables close to a full charge in less than 10 minutes, comparable to combustion engine vehicle refuelling times.

The Porsche Taycan, introduced in 2019, was the first model to use an 800 V architecture – a stark change from the 400 V architecture used before that date, and which still accounts for most EV models available today. The Lucid Air, introduced in 2021, was the first to adopt a 900 V architecture. Since then, Chinese manufacturers have driven the development of high‑voltage EV platforms (above 450 V), releasing more such models than all other automakers combined.

The trend towards greater EV battery voltage reached a turning point in 2025, with the release of the first-ever 1 000 V models (BYD Han L and Tang L) alongside megawatt charging for electric cars. Over the course of the year, more than 30 new high-voltage electric car models were released globally – over 80% of them by Chinese manufacturers – 25% more than in 2024 and twice the number of models released in 2023. The expansion of high‑voltage battery packs and associated ultra‑fast charging systems has continued into early 2026. Recent announcements include BYD’s 1.5 MW “flash charging” technology, Geely Group’s Lynk & Co 10+, CATL’s third-generation Shenxing battery, and Sunwoda Xingchi Supercharge Battery 2.0 battery – all enabling charging times of under ten minutes.

For consumers to fully benefit from these technological advances, ultra-fast charging infrastructure must be reliable and sufficiently widespread. In addition, the electricity grids must be resilient enough to accommodate higher peak loads from faster EV charging as higher‑voltage architectures and faster charging capabilities become more widespread. Today the number of electric cars able to use chargers above 250 kW remains limited, accounting for less than 5% of the vehicle stock in 2025, but sales are growing rapidly.