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In the future, realizing the inclusive cost reduction of fast charging technology and reducing the pressure on the power grid through vehicle-network interaction will become the focus of competition and development direction of the fast charging track. Fast charging technology has become the standard configuration of mid-to-high-end pure electric vehicles around the world.
As an important part of the platform architecture, the power battery has played a vital role in the fast charging revolution of electric vehicles. Around this, top 5 power battery companies fast charging technology, including CATL, CALB, Sunwoda, SVOLT, and EVE have already made active deployments.
1. How to realize the underlying technology of power battery fast charging?
In the power battery link, the fast charging capability of the battery depends on the rapid lithium insertion capability of the anode of the battery cell, the conductivity of the electrolyte, and the thermal management capability of the battery system.
During fast charging, lithium ions in lithium ion batteries such as lifepo4 battery, ternary lithium battery, etc. need to be accelerated and inserted into the anode instantaneously. This is a great challenge to the ability of the anode to quickly receive lithium ions.
If the anode does not have the ability to intercalate lithium at high speed, lithium precipitation or even lithium dendrites will appear, which will lead to irreversible decay of battery capacity and shorten the service life. In addition, the electrolyte also requires high conductivity, and at the same time requires high temperature resistance, flame retardancy, and overcharge prevention.
On the other hand, high-power fast charging will bring about a substantial increase in heat generation, and the thermal management of the high-voltage battery pack is crucial. Generally speaking, in the safety design of the battery pack, thermal diffusion protection can be carried out by applying a thermal insulation material with higher thermal insulation performance. But in addition to passive thermal protection, active thermal protection solutions are also crucial.
At the Shanghai Auto Show, various power battery companies such as top 10 power battery companies in the world also showed their talents in terms of material innovation and package thermal management.
2. Top 5 power battery companies fast charging technology list
① CATL Kirin Battery
Previously, CATL's ultra-fast charging technology has covered electronic grids, fast ion rings, isotropic graphite, superconducting electrolytes, high-porosity diaphragms, multi-gradient pole pieces, multi-pole ears, and anode potential monitoring.
Isotropic technology allows lithium ions to be embedded in graphite channels from 360 degrees, achieving a significant increase in charging speed. The anode potential monitoring can adjust the charging current in real time, so that the battery can exert the maximum charging capacity within the safe range of no lithium side reaction, and realize the balance between the limit charging speed and safety.
The ternary version of the Kirin battery uses a high-nickel cathode + silicon-based anode system, with an energy density of up to 255Wh/kg, and supports rapid hot start in 5 minutes and 80% charging in 10 minutes. However, during the charging and discharging process, the volume expansion of silicon can be as high as 400%, and the active material is easily detached from the pole piece, causing rapid capacity decay and forming an unstable SEI film.
Therefore, CATL's conductive material uses single-walled carbon nanotubes with a diameter of 1.5 to 2 nanometers, which has a stronger binding force to the silicon anode and a more sufficient conductive network. In addition, the electrolyte of the Kirin battery uses LiFSI and uses FEC additives to form lithium fluoride at the anode, which has a small ionic radius and can repair cracks in time.
In terms of thermal management, Kirin Battery integrates the liquid cooling system and heat insulation pad into a multi-functional elastic interlayer between the cells. Compared with the traditional liquid-cooled plate solution laid on the top of the battery cell, the heat exchange area has been expanded by 4 times. Thanks to the larger cooling area, the temperature control efficiency of the battery cell has increased by 50%.
② CALB "Top Stream" Battery
In the field of 800V high-voltage fast charging, CALB has laid out two routes, the square one and the ultra-fast supercharged large cylinder. Its square products support 4C fast charging, and the large cylinder supports 6C fast charging. Regarding the square battery solution, CALB has developed a new iron-lithium battery and a medium-nickel high-voltage ternary battery based on the 800V high-voltage platform, which were installed in the Xpeng G9 last year, achieving 10-80% charging in 20 minutes.
The medium-nickel high-voltage ternary battery continuously improves the utilization rate of lithium and nickel resources by building a multi-dimensional high-speed lithium-conducting channel. At the same time, through the application of multiple technologies such as multi-element homogeneous doping and element directional gradient distribution, while obtaining high energy density, it can maximize product safety and performance stability.
In April this year, CALB launched the "Top Stream" battery, which uses integrated assembly technology to create an integrated collector plate directly connected to the top of the tab. Compared with ordinary electrodeless batteries, the "Top Stream" battery achieves a 70% reduction in the current flow path, a 27% reduction in ACR, a 40% reduction in DCR, a 50% reduction in structural internal resistance, and a 3% increase in space utilization.
③ Sunwoda "Flash Charge Battery"
In September 2022, Sunwoda released its super fast charging power battery product - SFC480. The product has a maximum charging power of 480kW, which enables a battery life of 200km in 5 minutes, 400km in 10 minutes, and 700km in one charge.
In terms of material innovation, SFC480 adopts a high-voltage low-cobalt Ni60 cathode system, and adopts composite coating and R element doping technology solutions to improve the product performance of the cathode material, so that the battery has high energy density, fast charging and high safety performance at the same time.
At the same time, SFC480 also introduces a new generation of 3D liquid cooling technology at the system level, achieving an energy retention rate of more than 85% at a low temperature of -20°C, and a volume utilization rate of more than 72%. The entire series of products has no heat dissipation.
At the Shanghai Auto Show, Sunwoda released the upgraded "Flash Charge Battery", which has the characteristics of ultra-fast charging, high safety, and extra durability. It further supports electric vehicles with a range of 1,000 kilometers, and can charge from 20% to 80% SOC in 10 minutes.
The key technologies of flash charging batteries include flash charging silicon material technology independently designed by Sunwoda, high-safety medium nickel anode, silicon-based system electrolyte technology, full life cycle adaptive overcharging strategy, high-precision coating & lamination technology, etc.
④ SVOLT Dragon Scale Battery
In 2022, SVOLT further developed nano-mesh silicon anode technology for high-energy-density battery solutions, covering network-building silicon technology, silicon-carbon fusion technology, double-layer coating technology, etc., and the cycle life is 10% higher than that of imported similar products.
As a new generation of high-safety power battery system solution for SVOLT, the dragon scale battery is compatible with full chemical system solutions such as iron-lithium, ternary, and cobalt-free. The cruising range can reach up to 1000+km, covering 1.6C-6C fast charging system.
The dragon scale battery adopts an innovative thermoelectric separation design, its thermal runaway discharge channel is located at the bottom of the battery pack, and the electrical connection area is located at the side of the battery pack. When thermal runaway occurs in the battery cell, the high-temperature gas-liquid mixture is quickly discharged along the discharge channel through the shortest path, which solves the problem of thermal runaway.
⑤ EVE Large Cylindrical Cell π System
At the Shanghai Auto Show, EVE revealed that its 46 series of large cylindrical batteries adopt a self-developed full tab structure and a nickel + silicon carbon material system, which has the characteristics of standardized design, manufacturing, and recycling. Different heights can be made around the diameter of 46mm, and the space can be flexibly utilized to be compatible with various models.
EVE also launched a π battery system at the press conference, which supports 9-minute fast charging. It has "π" type cooling technology and builds heat transfer channels on the top and left and right sides of the battery cell to achieve three-dimensional heat transfer and solve the problem of fast charging heating.
On the basis of CTP integration technology, the application of high-efficiency composite new materials and adhesives reduces the weight of the system by 10%, achieving small space, low weight, and high battery life. In addition, EVE has also launched square stacks, BEV square system, 12v battery or 48v battery system products, etc.
3. Conclusion
In the future, realizing the inclusive cost reduction of fast charging technology and reducing the pressure on the power grid through vehicle-network interaction will become the focus of competition and development direction of the fast charging track.
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