The new 75-kWh battery pack will not use both LFP cells and ternary cells like its predecessor and will begin deliveries soon with the 2024 models.
(Image credit: Nio)
In September 2021, Nio (NYSE: NIO) launched its 75-kWh hybrid battery pack, introducing lower-cost lithium iron phosphate (LFP) cells to its batteries for the first time, although the standard range pack still uses a small number of NCM (nickel, cobalt, and manganese) ternary cells.
Now, the company has announced that its 75-kWh standard range battery pack will use only LFP cells going forward, rather than hybrid cells as previously, seemingly aimed at further reducing costs.
Deliveries of the technologically upgraded 75-kWh standard range battery pack, which has been further optimized in terms of algorithms, materials, and performance, will begin soon, Nio said in a statement posted on its mobile app today.
The 75-kWh standard range battery pack now utilizes LFP cells manufactured by CATL, and its SOC (state of charge) estimation accuracy is consistent with hybrid packs that use Li-ion ternary battery cells and LFP cells, Nio said.
The upgraded pack leads the industry in LFP cell estimation accuracy, especially in low-temperature environments, the company said.
By optimizing the cell's internal current conductors and increasing the overcurrent area, the 75-kWh standard range pack's maximum charging power has been increased from 140 kW to 170 kW, and the 10-80 percent charging time has been shortened from 30 minutes to 27 minutes, Nio said.
To enhance acceleration performance at low temperatures, the pack's internal resistance has been optimized for more direct feedback during overtaking, according to the statement.
Additionally, through design improvements to the heating film and battery pack closure, insulation performance has been optimized for more efficient thermal management, Nio said.
Deliveries of the upgraded 75-kWh standard range battery pack will begin shortly with the 2024 models, Nio said.
Notably, Nio had already filed for the use of LFP battery packs for its models last year, setting the stage for the latest move.
A December 8 regulatory filing showed that 14 Nio models -- including eight on sale and six that had previously been sold -- saw changes to vehicle specifications.
All of those models added the LFP battery option, with CATL as the supplier of both battery cells and assemblies.
Nio announced the launch of the 75-kWh hybrid battery pack on September 23, 2021, with deliveries of models equipped with the pack beginning two months later.
Prior to that, the standard range battery packs circulating in Nio's battery swap system had a capacity of 70-kWh and the long range of 100-kWh, and they both used only ternary cells. The 70-kWh packs continued to be used after the 75-kWh packs were introduced.
The current mainstream battery packs include Li-ion ternary cells, as well as LFP cells, with the former usually used in high-end models. A special case is BYD, which currently uses blade batteries based on LFP chemistry across its entire model line, including the ultra-luxury Yangwang sub-brand.
Lithium ternary batteries have the advantage of high energy density and performance, but the disadvantages are even lower safety, poorer cycle life and higher cost.
LFP batteries have lower cost, longer life, and higher safety, but lower energy density and poorer low-temperature performance.
One of the most important drawbacks for LFP batteries is that SOC estimation is difficult, especially in low temperatures, which can lead to sudden power outages when the vehicle's indicated remaining capacity is low.
In 2021, Nio launched the hybrid pack by adding 12 Li-ion ternary battery cells to the LFP pack, it said today.
These ternary cells helped the LFP cells with SOC estimation accuracy corrections and created the industry's first dual-system cell BMS algorithm, the company said in the statement today.
In 2022, Nio's team embedded algorithms in the control software regarding the use of LFP cells only, for which gray-scale monitoring and testing was performed, it said.
After two years of iteration, a breakthrough in SOC estimation accuracy was achieved, with the error reduced to 3 percent, far better than the industry standard, according to Nio.
In terms of algorithms, the 75-kWh standard range battery pack also incorporates multi-scenario SOC calibration and utilizes a variety of charging, driving, and standstill conditions for SOC estimation accuracy correction, it said.
Meanwhile, Nio introduced self-discharge and self-learning algorithms to learn the self-discharge rate of LFP cells, solving the challenge of inaccurate SOC estimation accuracy of LFP cells due to consistency issues, it said.
In addition, Nio's in-house developed cloud-based algorithms and training model for BMS SOC estimation data allow for more accurate SOH (state of health) estimation for individual cells, which plays a key role in improving user experience, it said.
The 75-kWh standard range battery pack now uses LFP cells manufactured by CATL, whose SOC estimation accuracy is consistent with that of the hybrid pack, Nio said.
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