Cell Roadmap - Battery Design

When looking at a product roadmap there will be a request to understand how the energy storage system will improve throughout the lifetime of the product. Also, you will need to understand if the roadmap contains disruptive elements that might require a redesign of the product.

Sometimes these changes in technology can be very disruptive and very enabling at the same time.

Cell Energy Density Roadmaps

Wh/kg is a key metric that we look at when comparing cells. Looking at production values and adding roadmaps gives you an interesting view as to the future. Is 900Wh/kg credible when production cells have taken 30 years to move from 80Wh/kg to 300Wh/kg?

All of this is underpinned by the fundamental chemistry research, this fundamental research takes time to develop, understand and solve. Even then the new ideas in chemistry take time to industrialise. Quite a few fail at the scale-up phase.

energy density roadmap — *perhaps a pragmatic roadmap for improvement we are likely to see in Wh/kg?*

Also, it’s worth looking at the history of the battery.

Chemistry Roadmap

The chemistry roadmap is a useful guide. It shows the move to more nickel-rich chemistry as a drive to reduce cost and reduce cobalt dependency.

This also shows lithium anode and solid state as the next generation.

Within the cell roadmap there are a number of other technology threads that are trying to unlock energy density and reduce costs.

One of the simplest ways is to increase the size of the cell. Increasing the Ah capacity means less overhead in terms of supporting material, lower number of parts in the manufacturing process. Hence lower cost. The downside can be electrical and thermal performance of the cell. An example of this is the Tesla move from 18650 to 21700 to 46800.

3D Electrodes

Increasing the surface area and connection to the active materials can improve a number of features of the cell:

Energy density
Power density
Internal resistance
Lifetime
Thermal and mechanical behaviour

This technology could be used with existing chemistry to increase energy density by enabling an increase in the percentage of silicon used in the anode.