How do you view the rapid penetration of lithium iron batteries in 2021?

Today, many media reported that NIO will replace the original 70kWh ternary VDA module battery pack with a lithium iron phosphate battery pack, upgrading the capacity from 70 degrees (kWh) to 75 degrees (kWh), and plans to release it in the fourth quarter of this year. Here are a few interesting things:

1) We originally thought that lithium iron phosphate would penetrate faster in the A-class and A00-class vehicles, but the reality is that it may gradually penetrate into the B-class (Model 3, Han EV). The original consideration here was that the safety and cycle life of lithium iron phosphate would be helpful for operations, but the price reduction of batteries on the 2C side still made Xiaopeng and Weilai switch to the low-mileage version of lithium iron phosphate.

2) The effect of CTP combined with lithium iron phosphate is relatively good. Under the original ternary system, there is little difference between large modules and CTP. However, in the case of lithium iron phosphate, since the string number configuration is more flexible, the effect of introducing CTP is more obvious

3) From a long-term perspective, according to the current situation, it is inevitable that the demand for iron-lithium will exceed that of ternary batteries in the second half of the year.

Figure 1 The proportion of iron-lithium has been increasing

Part 1 Energy density estimation of lithium iron battery

Let's start with Tesla's iron-lithium battery cell. This low-profile battery cell is 82mm high, which is customized to match the height of Tesla's previous module. That is to say, under the specifications of 280*82*63mm, the energy density is 170Wh/kg. For NIO, it does not need such a short battery cell. According to the previous VDA module size specifications of 355*150*115, the height is 115mm, and the original battery cell inside is 95mm high.

Figure 2 Tesla's lithium iron phosphate battery cell

So it is estimated that the energy density of the battery cell can be increased to 180Wh/kg or even higher by upgrading the height from 82mm to nearly 100mm. After the original VDA module is integrated into CTP, part of the space of the beam inside is also allocated to the battery cell.

Figure 3 From VDA to CTP, we can switch from ternary to ferrophosphorus, and the volume energy density is also improved

The data breakdown for March has not been found yet, but according to the data that has been released, in February 2021, ternary batteries accounted for 65% of passenger cars, and iron-lithium batteries accounted for 34% (it will be higher in March); in February, iron-lithium batteries accounted for 95% of buses, and iron-lithium batteries accounted for 91% of special-purpose vehicles. After capturing a large demand for passenger cars, ternary batteries may be oriented towards high-end passenger cars.

Part 2: A00-level lithium iron phosphate is shared with two-wheeled vehicles

During the auto show, it is worth noting that lithium iron phosphate has penetrated into electric bicycles (this field is in demand for small battery packs). Hello Electric Vehicles released three models, A80 (Elf), A86 (Turing) and B80 (Moling), which will be launched in April, May and June respectively. These vehicles will be equipped with G58 large cylindrical battery cells (20Ah). This and Xinri’s three new automotive-grade lithium iron phosphate battery products, 48v20Ah (0.5kWh), 60v20Ah (1.2kWh) and 109v92Ah (10kWh), will gradually pull up the lower boundary.

Figure 4 Large cylindrical lithium iron phosphate battery

Summary: The rapid penetration of lithium iron phosphate in power batteries and other fields is mainly about safety and low cost. This rapid expansion strategy will change the past perception based on energy density.