To understand the Qilin Battery, it's essential first to grasp the concept of CTP (Cell-to-Pack) technology. CTP integrates the battery cells directly into the chassis without using modules, essentially creating a module-free battery pack. The core idea is to fit as many batteries as possible into the vehicle, maximizing storage capacity in the absence of more efficient battery materials—essentially "making the fuel tank bigger."
The Qilin Battery, developed by CATL (Contemporary Amperex Technology Co., Ltd.), represents the third generation of its CTP technology. It achieves a record-breaking volume utilization rate of 72% and an energy density of up to 255 Wh/kg. When installed in a vehicle, it enables a range exceeding 1,000 km. Based on the currently disclosed data, CATL’s Qilin Battery is the most energy-dense mass-produced battery pack on the market. In other words, automakers that adopt the Qilin Battery first will lead the way in achieving the 1,000 km range milestone for their EVs.
For comparison:
Tesla’s 4680 battery achieves a volume utilization rate of 63% with a pack energy density of 217 Wh/kg.
BYD’s latest CTB (Cell-to-Body) Blade Battery boasts a slightly higher volume utilization rate of 66%, but its pack energy density is 200 Wh/kg.
In contrast, CATL's Qilin Battery surpasses both with a 72% volume utilization rate and an energy density of 255 Wh/kg.
Advantages of the Qilin Battery:
Enhanced Safety: The integrated water cooling plate provides additional thermal insulation, preventing thermal runaway.
Improved Fast-Charging Performance: Dual-sided water cooling for battery cells enables faster heat dissipation.
Extended Cycle Life: Relaxed cell compression increases the cycle life by up to twofold, while the water cooling plate also acts as a cushioning layer.
Higher Energy Density: The three-in-one functionality of cooling, insulation, and buffering significantly saves space. This allows the Qilin Battery to achieve:
LFP (Lithium Iron Phosphate): 160 Wh/kg and 290 Wh/L.
High-Nickel NMC (Nickel Manganese Cobalt): 250 Wh/kg and 450 Wh/L.
This represents a 13% increase in energy capacity compared to Tesla’s 4680 battery.
Innovations in Qilin Battery
Redesign of the Cooling System
Qilin Battery introduces an integrated multifunctional elastic interlayer, combining support, cooling, insulation, and cushioning into one structure. This innovation integrates crossbeams, longitudinal beams, cooling plates, and insulation pads into a single layer.
A micron-scale bridge connection within the elastic interlayer accommodates the minor deformations of battery cells during
charge and discharge, enabling flexible adjustments.
The cooling system has been completely redesigned, with cooling plates placed between adjacent battery cells rather than on top. This positioning significantly increases the heat exchange area by fourfold and halves the temperature regulation time for the cells.
According to CATL’s official claims, the Qilin Battery supports 5-minute rapid heat activation and 10-minute fast charging to 80% capacity.
Dual-Row Back-to-Back Cell Layout
Battery cells are arranged in a back-to-back dual-row upright configuration, allowing for a higher number of cells. This layout enhances compatibility with fast-charging technology while significantly improving safety and volumetric efficiency.
Inverted Cell Arrangement
The Qilin Battery employs an inverted cell layout, enabling shared functionality between runaway gas exhaust and bottom impact protection. By integrating the battery's venting and safety buffer zones, the design increases space efficiency by 6%, boosting the overall space utilization of the battery pack.
Summary
The Qilin Battery does not alter the internal structure or materials of the cells but instead optimizes the battery system’s structural design. This highly integrated system structure enhances the overall volumetric efficiency of the battery pack, leading to a substantial improvement in energy density at the system level.
Potential Challenges of High Integration
While the Qilin Battery system's design is innovative, the high level of integration introduces engineering challenges, such as:
Use of high-strength aluminum profiles for structural components, requiring advanced extrusion and welding techniques.
Optimization of the cooling plate design, including water flow direction, branch flow distribution, and cooling capacity allocation.
Thermal isolation design to separate internal battery temperatures from external environmental conditions.
Electrical clearance, creepage distance, and insulation system optimization.
Precise cell sampling, control accuracy, and robust insulation detection mechanisms.
Qilin Cooling Plate
According to CATL's patent titled "Water Cooling Plate Assembly, Cooling System, Battery, Battery Enclosure, and Electric Device" (Application Publication Number: CN114497826A), details of the Qilin cooling plate structure reveal the following key innovations:
Dual-Layer Cooling Channels:
The cooling plate consists of inner and outer cooling channels arranged in a harmonica tube configuration.
One channel (e.g., the outer layer) serves as the liquid cooling path, while the other (e.g., the inner layer) functions as a non-liquid cooling path, such as air cooling.
This design allows flexibility; for instance, the liquid cooling channel efficiently dissipates heat, while the non-liquid cooling channel, being free of coolant, provides a deformable pathway.
Deformation Buffer for Cell Expansion:
The walls of the non-liquid cooling channels are designed to deform inward slightly to absorb the expansion of individual battery cells during operation. This feature minimizes pressure on the cells, preventing damage caused by physical compression and ensuring long-term reliability.
Evolution of CATL's CTP Technology
From the first-generation CTP to the latest third-generation Qilin Battery, the volume utilization rate of the battery pack has increased significantly from 55% to 72%.
CTP 1.0
Key Features: Introduced "virtual large modules" by removing the module side plates and replacing them with straps.
Energy Density: Exceeds 180 Wh/kg.
Representative Model: BAIC EU5.
CTP 2.0
Key Innovations:
Implemented partition design in the bottom pack structure.
Removed end plates from the modules, replacing them with longitudinal and transverse beams in the pack casing.
Compatible with No-Thermal-Propagation (NP) Technology and AB Batteries.
Energy Density: Exceeds 200 Wh/kg.
Representative Model: NIO with a 75 kWh battery pack.
CTP 3.0 (Qilin Battery)
Side-mounted water cooling plate, doubling as an insulation layer and enhancing cooling performance.
Enabled high-rate fast charging by improving system cooling capabilities.
Removed longitudinal beams in the casing and utilized the clamp plates between cells for structural support.
Energy Density: Exceeds 250 Wh/kg.
| CTP1.0 | CTP2.0 | CTP3.0 |
km | 500+ | 600+ | 1000+ |
Wh/kg | 180+ | 200+ | 250+ |
Comparison: CATL CTP 3.0 (Qilin Battery) vs. Tesla CTC (4680 Battery) Aspect | CATL CTP 3.0 (Qilin Battery) | Tesla CTC (4680 Battery) |
Core Innovation | System-level integration: redesigns the cooling, insulation, and structural elements into a unified system. | Cell-level innovation: introduces larger cylindrical cells with a new tabless design for efficiency and thermal performance. |
Cooling Design | Water cooling plates placed between cells, serving as structural support and thermal insulation. | Water cooling plates also placed between cells but without structural support. Additional cooling plate layer above the cells. |
Thermal Performance | Effective but slightly limited by compact integration. | Superior due to larger cooling gaps and enhanced heat dissipation from additional top cooling plate. |
Space Utilization | Volume utilization rate: 72% , optimized for high energy density. | Volume utilization rate: lower than Qilin Battery , as cylindrical cells and extra cooling layers take more space. |
Fast Charging | Enabled by side-mounted cooling plates and optimized heat dissipation. | Enhanced by tabless design and superior cooling, facilitating high-speed charging. |
Energy Density | Achieves >250 Wh/kg , enabling up to 1,000 km range . | Slightly lower due to reduced space utilization, but efficiency compensates for range requirements. |
Qilin Battery achieves higher space utilization, making it ideal for applications demanding maximum range and compactness.
Tesla's 4680/CTC prioritizes thermal performance and fast charging, benefiting from innovations like tabless cells and a more spacious cooling arrangement, though at the cost of space efficiency.
Each approach reflects the respective company's priorities: CATL focuses on system optimization, while Tesla emphasizes cell and performance innovation.
CATL CTP 3.0 vs BYD CTB
BYD's CTB adopts an upper direct cooling plate design, and there is no cooling design between the cells, so its cooling performance is inferior to that of the Qilin battery and is not conducive to heat dissipation during fast charging. BYD's CTB still retains the lateral steel beams that provide strength/stiffness, resulting in better structural strength than the Qilin battery, but with a lower volume utilization.
Qilin Battery vs. SAIC Cube Battery
The Cube Battery is a collaborative product between SAIC and CATL. The Qilin Battery and Cube Battery share high similarities, both using a vertical cooling structure. However, the Cube Battery adopts a dual-cell horizontal layout, unlike the side-by-side layout of the Qilin Battery. Additionally, the Cube Battery lacks the expansion compensation sheet and the thermal insulating aerogel isolation layer between the cells, which prevents it from achieving true heat diffusion control. As a result, the Qilin Battery performs better in controlling heat diffusion. The Cube Battery is thinner in the vertical direction, but its volume utilization rate is lower than that of the Qilin Battery.
In conclusion, the excellence of the Qilin Battery is undeniable. As the largest "fuel tank" currently in production, the Qilin Battery is outstanding in terms of product performance.
The cooling plate of the Qilin Battery replaces the horizontal and vertical beams of the battery pack, incorporating a dual-layer cooling channel design while serving four major functions: support, water cooling, thermal insulation, and buffering. Additionally, the cells are arranged in a back-to-back double-row side-by-side layout, allowing for the inclusion of more cells. This results in improved overall safety, fast-charging performance, cycle life, and specific energy. The Qilin Battery is an important way for the company to further enhance battery performance through structural innovation within the existing square battery technology path. The lithium iron phosphate + Qilin battery can compete with the Blade Battery, while the high-nickel ternary + Qilin battery can compete with the 4680. The company previously stated that it would mass-produce Qilin batteries in 2023 that meet the non-thermal-diffusion requirement and can achieve a driving range of up to 1000 km.
Sum
In conclusion, the Qilin Battery represents a significant breakthrough in battery technology, leveraging innovative structural designs to enhance safety, energy density, fast-charging capabilities, and cycle life. By combining advanced cooling systems and optimized cell arrangements, it stands as a competitive solution against industry-leading technologies such as Blade Battery and 4680. With its ability to achieve a driving range of up to 1000 km and meet stringent thermal safety requirements, the Qilin Battery underscores its position as a transformative product in the evolution of energy storage systems.
FAQ
1. What is the main innovation of the Qilin Battery compared to previous CTP generations?
The Qilin Battery features a highly integrated structure that combines cooling, support, insulation, and buffering into a single water-cooling plate. It adopts a dual-layer cooling channel design and a side-by-side cell arrangement for enhanced energy density, safety, and fast-charging capabilities, with a volume utilization rate of up to 72%.
2. How does the Qilin Battery compare to Tesla's 4680 and BYD's Blade Battery?
Tesla 4680: The Qilin Battery has a higher energy density due to its structural efficiency but slightly lags in cooling performance and fast-charging capability, as Tesla’s design uses larger thermal dissipation areas and tabless cells.
BYD Blade Battery: The Qilin Battery offers better cooling efficiency and supports thermal runaway prevention through its integrated insulation layers, whereas the Blade Battery relies on a simpler direct cooling design with lower volume utilization.
3. What are the Qilin Battery’s advantages in energy density and range?
The Qilin Battery achieves an energy density of up to 255 Wh/kg with high-nickel ternary cells, enabling vehicles to reach a driving range of 1000 km. This is the highest energy density for mass-produced battery packs currently available.
4. How does the Qilin Battery enhance safety?
The integrated elastic layer with thermal insulation and buffering properties effectively prevents thermal runaway from spreading across cells. Additionally, the innovative water-cooling system placed between cells improves heat dissipation efficiency and shortens temperature control time, ensuring better safety during high-power charging and discharging.
5. When will the Qilin Battery be commercially available?
CATL announced that the Qilin Battery would meet mass production requirements in 2023, with its application in electric vehicles capable of achieving long ranges and stringent thermal safety standards.
The SAIC Rubik’s Cube Battery is a notable counterpart, developed in collaboration with CATL. While both adopt vertical cooling structures, the Rubik’s Cube Battery uses a dual-cell horizontal layout and lacks the Qilin Battery's elastic compensation layer and aerogel insulation, which compromises its thermal runaway prevention capabilities. Despite its thinner vertical profile, the Rubik’s Cube Battery has a lower volume utilization rate compared to the Qilin Battery.
