Youtuber The Limiting Factor brought you the disassembly and analysis of Tesla’s latest 4680 battery and gave some unique design specifications for this battery. The Model Y produced by the Texas factory is currently Tesla’s most advanced product. It uses the three cutting-edge technologies of CTC technology (the technology of directly installing the battery cell to the chassis), 4680 battery and one-piece die-casting, which can significantly reduce the production and assembly difficulty and cost of the vehicle, and improve the performance.
According to reports, the cathode of the Tesla 4680 battery uses NCM811 material, while the anode is graphite. The video shows that Tesla’s in-house 4680 battery (about 6 months ago) is equipped with NCM 811 cathode chemistry, the material has 81.6% nickel, while the cobalt and manganese levels have not been revealed, but there appears to be no aluminum (so no NCA or NCMA).
The Limiting Factor points out that the new dry cell electrode technology has not been used in cathodes, but it is currently used in anodes, and it is expected that it will be applicable or not applicable in both cases.
The analysis found that there was no silicon in the anode material of the 4680 battery and that the anode active material was graphite. It is reported that battery manufacturers usually add 10-15% silicon to the anode of state-of-the-art lithium-ion batteries to improve energy density. At this point, this early 4680 battery may be different from the chemical electrode technology currently used by Tesla.
Nevertheless, data analysis shows that this battery has very good characteristics, such as energy density up to 272-296Wh/kg. The Tesla 4680 battery is said to weigh 355 grams and has an estimated total capacity of 26.136 Ah, while the total energy is estimated to be 96-99 Wh (assuming 3.7-3.8 V), which matches the rumored 98 Wh.
The energy density of the 4680 battery is in the range of about 272-296 Wh/kg, which is very good among the batteries currently on the market, and basically belongs to the performance of the first echelon. As a reference, the Ningde era CTP3.0 Kirin battery, which will be mass-produced next year, will achieve a new global level of integration, with a volume utilization rate exceeding 72% and an energy density of 255Wh/kg. Of course, the advantage of CATL lies in the world’s first large-surface cooling technology for battery cells. Kirin batteries can support a 5-minute fast hot start and a 10-minute fast charge.
Estimated total energy: 96-99 Wh (assumed at 3.7-3.8 V)
Estimated energy density: 272-296 Wh/kg
Troy Teslike pointed out that Tesla’s first-generation battery is rumored to be 98 Wh. Models with higher energy density will be introduced in the next few years: 108 Wh in 2023 (an increase of 10%) and 118 Wh in 2024 (an increase of 9.3%).
The 4680 battery is said to have stored more than 5 times more energy than the smaller 2170 battery. Taking into account the rumored total energy content, the energy density is:
Gen 1: 276 Wh/kg
Second generation: 305 Wh/kg
3rd generation: 333 Wh/kg
However, it was also pointed out in April that the 4680-type battery may have two battery pack configurations:
Standard: 690 batteries (69 x 10) and 67.620 kWh (98 Wh / battery)
Long range: 828 cells (69 x 12) and 81.144 kWh (98 Wh/battery)
Of course, the current 4680 Model Y is not listed as a long-range version in the EPA’s filing, but only as AWD, its range is not much better than the version with the 2170 battery (279 vs 330).
In addition to this, the steel casing (battery skin) of the new battery is much thicker than the 2170-type battery. Foreign media believe that the reason behind this is likely to be that the new battery pack structure requires a stronger carrying capacity. Therefore, it makes the 4680-type battery heavier. According to the video, this part of the weight loss is estimated to be 10-15%.
Model 2170: 125-250 microns
Model 4680: 500-600 microns
But as we saw above, despite this, the two energy densities are comparable:
Model 2170: 263-276 Wh/kg
Model 4680: 272-296 Wh/kg
Although the potential of the 4680 battery has not yet been tapped, since it has a structural battery design, it means that Tesla will be able to further reduce weight at the structural level of the car, making the energy density at the car level significantly higher. At least, that’s what Musk said in 2018.
The video shows that the new battery could have such a competitive energy density (despite the heavy can and no silicon anode) due to the thickness of the electrodes (more active material).
In the case of the new cells, the cathode thickness seems to be 20-25% higher:
Type 2170 (typical): 60-70 microns (0.06-0.07 mm)
Model 4680: 85 microns (0.085 mm)
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