Skip to main content

Boosting Battery Energy Density in Electric Vehicles

Periodic Reporting for period 1 - LeydenJar (Boosting Battery Energy Density in Electric Vehicles)

Reporting period: 2017-04-01 to 2017-08-31

The energy density of current Lithium-ion battery cells are not good enough to serve their purpose in Electric Vehicles, consumer electronics, aviation, and renewable energy storage. This leads to suboptimal range of EV's, too high cost per kilometer, and smart devices that cannot tap the intelligence of the processor, as battery advancement can't keep up with Moore's law.

The bottle neck is in the anode layer of Li-ion battery cells. Graphite anodes have reached their current theoretical maximum. Silicone is a better material, with the potential to hold a tenfold capacity over graphite anodes. However, pure silicon expands when it is used as battery material, leading to mechanical instability after 2-3 cycles of loading and unloading.

We have found a solution to make pure silicon anodes, without the associated problem of breaking apart. The impact on energy density is an increase of 50%, leading to the highest energy density of battery cells seen thusfar in the world. The potential impact on the acceptance of electronic vehicles and storage of renewable energy is very significant.

The objective of this EASME study is to investigate the ability to scale up our production tool of making pure silicon anodes, leading to a potential cost parity with the existing anode production process.
Development of Li-ion battery cell prototype (pouch cell) based on our silicon anode.
Adjustment of electrolyte to fit with pure silicon.
Creating a thicker anode layer (50x scale up) to 7-10 micron
Cell balancing in coin cell and pouch cells
Increasing the coulombic efficiency and cycle life

The feasibility study was aimed at modeling the total existing cost of graphite production, cost modeling of our roll-to-roll PECVD production tool, benchmarking, and assessing the roadmap of a scale up in terms of realistic assumptions, technical abilities and engineering requirement. Furthermore assessed the technical fit with the overall battery manufacturing process, and the strategic advantages of producing on a one step process rather than a five step coating process.

We have concluded that the PECVD tool has the ability to be scaled up for application in a large battery manufacturing plant, and that it can reach cost parity with the existing coating process in due course. We are now preparing a new machine track to do R&D on the existing machine, to see if we can improve the key speed vectors, and to prepare a base plant demonstrating high speed production and generating pure silicon anode rolls for use in testing programs.
We have reached our milestone of 100+ cycles in a Li-ion pouch cell, cycling at constant capacity of 1.000 mAh/g (3x existing anode capacity). Based on our test results we have engaged large European corporates to test our material. We have been recognized by BMW by winning its BMW Startup Garage competition, beating 62 high tech ventures world wide. We will now investigate potential cooperation with BMW. Furthermore we fit perfectly in a European battery manufacturing initiative.