Qilin battery vs Tesla CTC vs SAIC rubik’s cube battery
Introduction to qilin battery
At the same time, the qilin battery also adopts the world’s first large-area cooling technology for batteries, which can support a quick hot start in 5 minutes. This article will introduce qilin battery technology in detail and compare it with batteries from different lithium battery manufacturers.
Detailed explanation of qilin battery technology
Qilin battery pack
According to the patent documents of CATL, we can find the structural details of the qilin battery pack, and its main innovations are as follows:
1. Square-shell batteries are arranged in the box in a back-to-back and side-to-side manner, instead of the original upright way, so more single batteries can be placed, which is more conducive to fast charging and improves volume utilization.
2. The cooling plate replaces the horizontal and vertical beams, which integrates the functions of support, cooling, heat insulation and buffering, and effectively improves the space utilization rate. The new cooling plate is inserted in the form of a reinforcement between the battery rows and connects both the upper cover and the lower box, acting as a traditional cross-beam support and protection.
Two rows of cells sharing one cooling channel, compared to one row of cells using one water cooling plate, reducing the number of cooling plates, lowering the BOM cost, having a lightweight effect, and more conducive to heat dissipation during fast charging.
The vertical cooling plate creates horizontal relative isolation space and vertical expansion compensation sheet + thermal insulation aerogel between the cells, which effectively insulates the cells to achieve “zero thermal runaway”.
The cooling plate adopts both internal and external cooling channels, which can absorb the expansion generated by battery charging and discharging and ageing, reduce the extrusion of the cells and improve the cycle life of the batteries.
In addition, the new water cooling plate is transferred to the interior of the case, which can avoid the risk of liquid leakage due to breakage caused by collision.
3. The lower box has a positioning/limiting groove, which is used for the installation of the cooling plate and the fixing of the battery pack. This design can improve the stability of the installation of the lithium battery pack and avoid mutual collision damage, but the heat-conducting structural adhesive is still required to ensure the strength and Optimize heat dissipation.
Qilin cooling plate
According to the patent documents of CATL, we can find the structural details of qilin cooling plate, and its main innovations are as follows:
The water-cooled plate has two cooling channels inside and outside, using the harmonica tube method, where one of the outer and inner cooling channels is liquid-cooled and the other is non-liquid-cooled (e.g. outer liquid-cooled, inner air-cooled).
As the non-liquid-cooled channels are not filled with cooling liquid, the channel walls can be properly deformed inwards to absorb the expansion of the battery monomer and avoid damage to the battery monomer extrusion.
Qilin battery innovation
The water-cooled plate replaces the horizontal and vertical beams of the battery pack, superimposes the double-layer cooling channel design, and has four major functions of support, water cooling, heat insulation, and buffering.
In addition, the qilin battery cells are arranged sideways in a double-row back-to-back manner, so more batteries can be put in, which is more conducive to fast charging technology, and at the same time, the safety and volume utilization rate are greatly improved.
The qilin battery does not place the water-cooling plate at the bottom, but inserts it between the cells. The water-cooling effect is greatly enhanced. The benefits are:
1) The safety is greatly improved, and the water-cooled plate has additional heat insulation effect, which can realize no heat diffusion.
2) To improve the fast charging performance, the double-sided water cooling of the battery cell.
3) To improve the cycle life, the life of the qilin battery will be shortened by half after tightening, that is, if it is relaxed a bit, the cycle life can be doubled, and the water-cooled plate has an additional buffering effect.
4) Improve specific energy: water cooling, heat insulation, and buffer functions are three-in-one, and the space is greatly saved. Lithium iron phosphate can reach 160Wh/kg and 290Wh/L, and ternary high-nickel can reach 250Wh/kg and 450Wh/L. The 4680 packs 13% more electricity.
CATL CTP technology iteration
From the first-generation CTP to the latest third-generation qilin battery, the volume utilization rate of the battery pack has increased from 55% to 67%.
CTP1.0: Remove the side panel of the module and replace it with straps, representing the model BAIC EU5.
CTP2.0: Remove the two end plates of the module, and use the vertical and horizontal beams on the box to replace the end plates, representing the model NIO at 75 degrees.
CTP3.0: further remove the vertical and horizontal beams on the box, and use the splint between the two cells and the cell body to meet the structural requirements.
Comparison between CATL CTP3.0 and potential competitors
CATL CTP3.0 VS Tesla CTC
The placement of the qilin battery water cooling plate is similar to that of the Tesla 4680 battery. The water cooling plate is sandwiched between the cells, but the Tesla water cooling plate does not need to support it.
The heat dissipation space between the large cylinders is larger, and there is an additional layer of water-cooled plates on the top, so the heat dissipation effect of Tesla CTC is better than that of qilin battery. The superimposed full-tab design is very conducive to fast charging design, but the space utilization rate must be lower than that of qilin battery.
CATL CTP3.0 VS BYD CTB
BYD CTB adopts the design of the upper direct cooling plate, and there is no cooling design between the cells, so its cooling effect is inferior to that of the qilin battery, which is not conducive to the heat dissipation of the battery during fast charging.
BYD CTB still retains the transverse steel beams that provide strength/rigidity. The structural strength is better than that of qilin battery, but the volume utilization rate is lower.
Qilin battery VS SAIC rubik’s cube battery
The rubik’s cube battery is a joint product of SAIC and CATL. The qilin battery and the rubik’s cube battery have a high similarity, and both adopt a vertical cooling structure, but the rubik’s cube battery adopts a double-cell lying layout instead of the qilin’s side-standing layout. There is no expansion between the upper and lower cells.
The isolation layer of compensation sheet + heat-insulating aerogel cannot be truly heat-free, so qilin batterry is better at controlling heat dissipation. The rubik’s cube battery is thinner in the vertical direction, but its volume utilization rate is lower than that of the qilin battery.
Conclusion
1) Further innovation in structure. The water-cooled plate of the qilin battery replaces the horizontal and vertical beams of the battery pack, superimposes a double-layer cooling channel design, and has four major functions of support, water cooling, heat insulation, and buffering.
In addition, the qilin battery cells are arranged sideways in a double-row back-to-back manner, so more batteries can be put in, and the overall safety, fast charging performance, cycle life and specific energy are better improved.
Qilin battery is an important way for the company to further improve battery performance through structural innovation under the existing prismatic battery technology route.
Iron-lithium + qilin battery can compete with blade batteries, and high-nickel ternary + qilin battery can compete with 4680. The company previously stated that it will mass-produce qilin batteries in 2023 that meet the requirements of no heat dissipation and have a cruising range of up to 1,000km.
2) Qilin battery has increased structural requirements for the battery cells and increased demand for water-cooled plates.
Due to the simplification of pack formation, the safety requirements for the qilin battery cells themselves have increased, and the demand for structural parts (such as explosion-proof valves) has increased, so the value of structural parts of the battery cells has increased slightly.
At the same time, the demand for water-cooled plates has increased due to the replacement of the cross and longitudinal beams of qilin battery packs by water-cooled plates.
3) Qilin battery is conducive to accelerating the iteration of 4C super fast charging: it can stimulate the demand for fast charging lithium battery materials, such as high nickel single crystal positive electrode, fast charging negative electrode, electrolyte additive Lifsi, conductive agent, etc.
