from chemistry to pack
The BYD FC4680P cell is a Lithium Iron Phosphate chemistry in the Tesla 4680 cell format. 4680 => 46mm in diameter and 80mm high A small plug in the top is described as an “explosion proof valve”. Only high level data is available on manufacturers spreadsheet and no independent test data has been found. Key … Read more
Recent industrial and academic studies have shown that aluminium cell housings can provide several benefits in terms of thermal management and gravimetric energy density in particular1,2,3. However, as Cell-To-Pack and Cell-To-Chassis approaches arise the battery cell and therefore, the battery cell housing, become part of the structure of the battery electric vehicle contributing with their … Read more
Base vs side cooling of cylindrical cells is often brought up in online discussions and in many OEMs designing battery packs. We looked at this before within Thermal Conduction in a Cell, however, I think it is worth expanding this topic. The Tesla design cools the side of the cell and the Lucid Motors cools … Read more
A 4680 cell concept The battery industry is targeting larger cell formats, which enable simplified module design and cell-to-pack or even cell-to-chassis solutions. In this regard, hard case battery cells and in particular cylindrical cells will play an important role in enabling the named developments. Tesla’s announcement of a tabless 4680 cylindrical LIB has triggered … Read more
Cylindrical Cell Electrode Estimation: An alternative geometric approach. Here we present a simple method for estimating electrode length in a cylindrical cell. The method is equally applicable to other formats since we make an estimation of the total active electrode area. Results require knowledge of one electrode Active Material (AM) chemistry, electrode porosity and thickness … Read more
Using some simple mathematics and dimensions we can do some cylindrical cell electrode estimation. Knowing the outer and inner diameter of the spiral along with it’s thickness we can calculate the length of the material to create it. D is the inner diameter of the cylindrical can. The inner diameter is that of the mandrel … Read more
In this Article, we will compare different Cylindrical Cell Sizes used in electric Vehicles. 4680 vs 21700 vs 18650.
Caution: This is a very difficult pack to reconcile the numbers around at the moment and so we are continually updating our calculations and estimates. We will get there, but it might take some time. Specifications: Assuming the 4680 cell from the Munro teardown is correct at 23.35Ah then we have the following parameters: Assuming … Read more
Indicative numbers for the Tesla 4680 cathode porosity, estimated based on 2D images of the Batch 1 and 2 cells originally analysed for The Limiting Factor by the Laboratory for Energy Storage and Conversion, UC San Diego. This image analysis and estimation was performed by Addionics based on the original Tesla 4680 cell benchmarking. Analysis … Read more
Cell Specifications the first outing for the Tesla 4680 is without Silicon in the anode, this might be a move to reduce costs, reduce the cell expansion or to present a strong energy uplift roadmap for the vehicle This lower height cell will have been selected for use in saloon / crossover type vehicles. However, … Read more