Blog

Oct 27, 2024

CATL Freevoy Battery Optimized For EREV & PHEV Vehicles - CleanTechnica

Just about the hottest cars in the Chinese new car market are EREVs (extended range electric vehicles) and PHEVs (plug-in hybrid vehicles). The distinction between them can be filled with technical

Just about the hottest cars in the Chinese new car market are EREVs (extended range electric vehicles) and PHEVs (plug-in hybrid vehicles). The distinction between them can be filled with technical jargon, but, in general, an EREV has a battery large enough to handle most daily driving needs without any outside assistance but also has an internal combustion range extender engine to recharge the battery while driving when necessary. BYD has models for sale in China it claims have a combined range of 2,100 kilometers (1,305 miles). Not only do they have substantial battery packs to make that possible, the gasoline engines that supplement the batteries are some of the most efficient ever manufactured, beating even the vaunted Toyota Prius engine in that regard.

CATL, the world’s largest manufacturer of lithium-ion batteries, has taken note of this trend toward electric cars with extended range and decided that it wants to join the party (BYD manufacturers its own batteries, for the most part). On October 24, 2024, it launched its Freevoy Super Hybrid Battery, the world’s first hybrid vehicle battery to achieve a pure electric range of over 400 kilometers and 4C superfast charging, which it says will usher in a new era for high capacity EREV and PHEV batteries and transform that sector of the new car market.

CATL has noted that those cars are gaining prominence in the new energy vehicle market because consumers have consistently expressed frustration with battery electric cars that suffer from short range, slow charging, and reduced performance in cold weather. Those factors have emerged as critical challenges that demand immediate solutions. Designed specifically for EREVs and PHEVs, the Freevoy battery from CATL frees drivers from the constant need to charge, a common drawback of existing hybrid vehicles. The new battery allows many drivers to commute for a week before recharging if needed. In addition, it delivers impressive charging speeds that can provide an additional 280 kilometers of range in only 10 minutes using a Level 3 charger. That practically eliminates range anxiety for owners of those cars.

Behind the remarkable range and ultra-fast charging are a number of technology breakthroughs, according to Gao Huan, chief technology officer at CATL for electric cars in China. In his presentation during the introduction of the Freevoy battery, Gao said the Freevoy battery incorporates a surface modification technology for the cathode material, coupled with an innovative high voltage electrolyte formulation, to create a nano protective layer. This effectively minimizes side reactions within the active layer.

The integration of high-activity, excited-state particles into the cathode material significantly enhances transport efficiency of lithium ions within the material. Thanks to an upgrade to the control algorithm and hardware for the battery management system, the state of charge control accuracy of the Freevoy battery has been increased by 40 percent and the overall electric utilization rate has increased by more than 10 percent. Combined, these improvements make a range on battery power alone of more than 400 kilometers.

That translates to about 250 miles. Even using the more rigorous EPA standard rather than the optimistic WLTP standard that is the norm in China, that still suggests a car equipped with the Freevoy battery would probably be rated at between 180 and 200 miles by the EPA. The PHEV models available today in the US only have a range of about 30 to 50 miles, according to the EPA. Do you think buyers would be more interested in those cars if they could travel 4 to 6 times further?

CATL conducted model data analysis on the charge/discharge polarization characteristics of the Freevoy battery to accurately predict the future discharge capacity of the battery and create a multi-level power prediction and control strategy that improved the power performance of the hybrid vehicles by 20%. In addition, CATL has successfully applied its 4C ultra-fast charging technology to the Freevoy battery, adding over 280 kilometers of range in 10 minutes off fast charging. Lithium ion transport is made effortless through the application of cathode fast ion conductor coating technology, second generation fast charging graphite, novel nano-coating technologies for the anode, multi-gradient layered electrode design, and a brand new ultra-high conductivity electrolyte formulation, allowing hybrids to deliver the ultimate charging experience, equal to pure electric vehicles.

Up until now, one of the downsides of PHEV cars was that they were very slow to charge, which limited the amount of time operating solely on battery power on longer trips. Now EREV and PHEV drivers can charge in about the same time drivers of conventional cars need to refuel. Let’s face it — it takes most of us about the same amount of time to use the restroom and grab a snack at rest stops. Now drivers with the CATL Freevoy battery can stop, recharge, and be back on the road without having to watch their gasoline-powered friends disappearing over the horizon while they wait for charging to finish. (Note: CATL does not say what the power level was of the chargers they used to analyze the performance of the Freevoy battery.)

Sodium-ion batteries are less affected by cold temperatures. To take advantage of that characteristic, CATL added some sodium-ion battery cells to the Freevoy battery to break the low temperature limitations of conventional new energy vehicles. It achieves discharge capability in extreme cold environments down to -40 degrees Celsius, brings charging capability down to -30 degrees Celsius, and maintains a seamless driving experience down to -20 degrees Celsius comparable to normal temperatures.

To further improve the low temperature performance of the Freevoy, CATL has implemented three key technological innovations centered around sodium-ion battery technology. First, using CATL’s pioneering AB battery system integration technology, the Freevoy combines sodium-ion batteries and lithium-ion batteries in a defined ratio and arrangement, with mixed, serial, and parallel connections to enhance low temperature range by 5%. Second, CATL takes the sodium-ion battery as a state of charge benchmark for monitoring of the AB battery system to assist in calibrating the lithium-ion battery’s charge level. This elevates system control precision by 30%, adding over 10 kilometers to the pure electric range.

To address the inherent performance disparities between lithium-ion batteries and sodium-ion batteries at low temperatures, CATL has developed a BMS technology that is accurate across a broad range of temperatures. This technology implements targeted zonal management for distinct chemical systems around the clock, effectively mitigating issues like inaccurate charge prediction or reduced power performance in harsh high- and low-temperature environments.

CATL has established a comprehensive reliability management and evaluation system, starting from the material selection and molecular design and encompassing multi-level protection structures, extreme manufacturing processes, comprehensive testing and validation, and big data-driven early warning mechanisms. The Freevoy has already been in use in several different models manufactured by various brands, including Li Auto, AVATR, and others. By 2025, 30 hybrid vehicle models from brands including Geely, Chery, GAC, and Voyah are scheduled to be built with the CATL Freevoy battery. With this new battery technology, CATL continues to push the boundaries of technological innovation and accelerating the shift toward comprehensive electrification.

At CleanTechnica, we continue to insist the batteries that will power our electric cars in 2030 haven’t been invented yet. CATL is showing that great progress toward those future batteries is possible and that there is more to come. The EV revolution is just getting started, at least in many countries not in North America or Europe.

CleanTechnica's Comment Policy