Pouch Cell Design and Edge Cooling

Looking at the pouch cell design and edge cooling evolution allows us to appreciated the importance of battery cell electro-thermal behaviour. Fundamentally pouch cells are made from multiple layers of active material all applied to copper and aluminium electrodes that are sandwiched and compressed together. The copper and aluminium electrodes have very good in-plane thermal … Read more

Electrical Contact Resistance

The Electrical Contact Resistance at a metal to metal contact is primarily governed by: The surface structure can be further described by the surface flatness, surface oxidation and water adsorption. These joints in a battery pack will either be welded or bolted. Initially the easiest to think about is the bolted busbar joint. The bolt … Read more

Pouch Cell Cooling

Looking at the benchmarks there are a number of pouch cell cooling options that have been used and threads where we can see improvements to designs. Firstly thought it is worth just reminding ourselves of the heat generation mechanism in a battery cell. Heat Generation in a Cell can be defined quite simple for the … Read more

Cylindrical Cell Electrode Estimation

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

Cell Electrode Pressure

The cell electrode pressure is required to keep the cell operating at it’s peak performance over it’s lifetime. However, is there an optimum pressure and why exactly does the cell need it? As the cell is charged lithium ions move into the graphite anode and the cell will increase in thickness. Silicon in the anode … Read more

Road Vehicle Power Demand

Let’s look at the road vehicle power demand for the simple steady state condition. We will look at the tractive effort and power required: Aerodynamic Forces The aerodynamic forces on the vehicle are proportional to velocity squared and hence become dominant at high speed. FA is the frontal area and Cd is the drag coefficient. … Read more

2022 Tesla Model Y 4680

Tesla 4680 battery cooling

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