Challenges faced by the development of 18650 lithium-ion batteries.
The challenges faced by the development of 18650 lithium-ion batteries are that, in the face of the current situation where people are constantly increasing their specific energy, if the external dimensions remain unchanged and the energy density is also increased, 18650 faces many challenges:
1) The supply chain of new materials such as NCA and silicon carbon is not yet mature, with high costs and unstable supply. For example, the higher energy density material 811 has a gap in stability and process control compared to mass production. As a result, in the short term, the 18650 of 811 is much more expensive, but its performance is poor;
2) New material manufacturing process has high environmental requirements, high fixed assets investment and huge energy consumption;
3) Low capacity of individual batteries, high requirements and costs for PACK grouping technology;
4) Single cell batteries can adapt to both positive and negative bipolar ear structures at most, and have a significant impact on energy density;
5) When high energy density and high rate charging are required simultaneously, the design space is very small. 18650 uses 523+graphite system, and according to the new national standard, achieving 2.4AH at 1C has reached the design limit.
Larger diameter cylindrical lithium-ion batteries will become an inevitable trend, as shown in the data below. Comparing larger sized cells with 18650 in terms of ear design and winding curvature, large-sized cells show significant advantages.
