Cost analysis of square lithium ion battery and cylindrical lithium ion battery

Beijing, Hebei and Tianjin have launched odd-even license plate restrictions. One of the common features of the policies of the three places is that the limited travel measures only target traditional fuel vehicles. New energy vehicles are not restricted and can be driven on the road at any time. Countries in order to promote the development of new energy vehicles, not only provides new energy vehicles with national and local levels of fiscal subsidies, also be exempted from the new energy vehicle purchase tax, and in Beijing, Shanghai, Tianjin and other car plate restrictions, also a new energy cars unlimited CARDS, countries to support the development of new energy vehicles is spare no effort, but the new energy automotive industry ultimately must carry on the marketing operation, short-term stimulus does not guarantee the healthy development of new energy vehicles industry, only after boot, this industry into a virtuous cycle, to achieve sustainable development.

The problem now facing new energy vehicles, in addition to people mistrust of new energy vehicles, in fact, the biggest problem is the price factor, with byd qin plug-in hybrid car, for example, to remove state subsidies, revoke after tax and buy the cost of the plate, land prices have risen to 16-170000, and the price of pure electric vehicles is as high as more than 200000. At this price, people can choose fuel vehicles with higher safety configuration and better comfort. Therefore, once the state subsidy is withdrawn, the price of new energy vehicles will rise further, and the development of new energy vehicles is still a puzzle.

For new energy vehicles, the cost is the biggest impact of the lithium ion battery energy storage system, is currently used on car more cylindrical battery, cylindrical battery cost mainly by size and thickness of the electrodes, and the influence of factors such as the choice of materials and the scale of production, but now the size of the cylindrical battery through ascension and the way of increasing the thickness of electrode has little to reduce the cost, while square battery in lower cost and great potential to mining.

In order to the production cost of lithium ion battery in-depth analysis, people have developed many model, one of the most famous for Argonne national test BatPaC model of development, the model USES a variety of battery pack structure and the chemical composition of the battery, to calculate the cost per kWh battery, the scale of production from basic to 100000 groups of battery pack/set, the model was found to reduce SEI film forming cycle and alternative to expensive solvent, increase the thickness of the lithium ion battery electrodes, improve the capacity of lithium ion battery can reduce the cost of unit energy.

Rebeccae. Ciez of Carnegie Mellon university and his colleague J.F. Whitacre analyzed the cost of cylindrical battery and square battery using batpac-based cost model. They found that under the current technology level, the space for further cost reduction of cylindrical battery is small, while square battery has great potential to reduce the cost of lithium ion battery.

In the model, beccae. Ciez takes 18650 battery as the baseline, allowing it to increase by 10% in height and diameter in order to increase the capacity of the battery. The establishment of the model is divided into two main process, the establishment of physical model mainly includes battery capacity, size, the length of the cathode and the quality of the active material parameters, such as, the second is to establish cost analysis model, Rebecca e. Ciez according to the cost analysis model based on process (PBCM) the cost of the rectangular and cylindrical cell model is established.

Effects of lithium ion battery costs mainly include material, equipment, auxiliary equipment, maintenance, manpower, energy, construction and other factors, using the above model analysis can find the same using 70 microns electrode and 2 GWH production, LMO material battery only cost is the lowest, but to investigate the cost per KWh, LMO materials rather than NCA and sliding material cost is higher, the cost of the LMO is about 440 $/ KWh, while the cost of NCA and sliding is 276 $/ KWh and around 243 $/ KWh. The thickness of the electrode and the size of the battery have the most obvious impact on the cost of the battery. Increasing the thickness of the battery can significantly reduce the cost of the battery, and increasing the size of the battery can also significantly reduce the cost of the battery.

By comparing the cost of materials and processes in battery cost, it is found that material cost is the highest, accounting for about 40% of the total battery cost, followed by equipment cost and human cost. Nearly half of the cost of materials is the structural cost of the battery, such as the shell, terminals and seals. It is worth noting that the price of lithium carbonate has little impact on the cost of lithium ion battery. Even if the price of lithium carbonate increases from $7.5 /kg to $25 /kg, the cost of lithium ion battery will not increase by more than 10%. Using the above cost model, it is found that the cost of square battery is lower than that of cylindrical battery under the same capacity, which is mainly due to the reduction of the cost of square battery structure.

Based on the above cost model analysis, it can be seen that the material of lithium ion battery has an important impact on its cost. Although increasing the output helps to reduce the production cost, when the output exceeds 1GWh in that year, the cost reduction caused by increasing the output will be very slight. The cost of battery structure will also have a significant impact on the cost of lithium ion battery. The adoption of square battery can greatly reduce the production cost due to the flexibility of the design.