Power Management I Interview
Lighter and smaller
Neil Tyler talks to Dr Bill Macklin, CTO at Nexeon about the company’s work in developing silicon anode Li-ion battery technology. What are the key technical and manufacturing challenges in brings this technology to market?
Neil Tyler: The limitations of lithium ion battery technology are becoming increasingly apparent, so what are the main benefits of using silicon anode Li-ion battery technology?
Bill Macklin: The volumetric capacity of silicon (Wh/litre) is significantly higher than that associated with carbon anode materials - the potential contained within silicon holds great promise for the future of Li-ion batteries, if it can be used without compromising the battery cycle life. Nexeon’s technology solves the cycle life
problem posed by silicon, thus enabling its greater energy density properties to be harnessed for the next generation of Li-ion batteries. The energy density of silicon anode Li-ion batteries can be up to 10x higher than carbon anode Li-ion batteries. This translates to up to double the energy storage of batteries and maybe more when other parts of the battery have been optimised. Silicon is cheap, readily available and you need less per battery. This means batteries can be lighter and smaller. An example of these benefits in practice would be a better electric car experience - by using a silicon anode Li-ion battery, as a result of its higher energy density, it would be able to cover greater distances between charges, and the battery unit itself could be cheaper.
NT: What are the main technical and manufacturing challenges in developing
24 May 2013
this technology, for example, how do you address the issue of mechanical stress as a result of charging and re-charging?
BM: Control over the morphology (physical structure) of the specially etched silicon particles is a key factor. It needs to achieve lots of charge with recharge cycles at different temperatures and loadings. Nexeon’s approach avoids the stress issue by structuring the particles as pillars at a nanoscale thereby avoiding pulverisation on cycling (see SEM pictures). We have a fully automated and instrumented pilot plant currently in full operation in the UK, and plans are in place for a volume manufacturing plant. This is a very exciting phase as we move from batch to continuous operation, and proceed with the build of 20 tonnes per annum plant in Oxon. Our recently announced partnership with Wacker Chemie will provide huge amounts of expertise in chemical engineering scale up for the 250 tonnes per annum plant and supply of high volume commercial quantities.
NT: Research has started on developing silicon fibres and particles in terms of battery design, what could future silicon architectures look like? And what could be the benefits?
BM: In principle silicon fibres can be fabricated into composite anode structures similar to those of the structured silicon
Components in Electronics
powder materials. The dimensions of the fibres does allow for thinner composite anodes, so potentially higher charge/discharge rates and very thin battery designs. The silicon fibres could also be bonded directly to the copper foil current collector for example, so potentially removing the need for the traditional polymer binder used in an anode composite. The advantage of this approach could be in the removal of the need for a process solvent (organic or water) for the polymer binder in the manufacturing process.
NT: What products or applications do you see this technology being used? How is work progressing in terms of taking this technology into electric vehicles? What are the road-blocks to deployment and acceptance?
BM: The immediate opportunity in the next 2 to 3 years is to see the silicon material adopted in the Li-ion batteries used in portable electronic devices such as phones, laptops, tablets etc. While in the medium term the key application is for EV and hybrid vehicles. With greater energy storage, and smaller, lighter batteries, we can significantly improve the performance of electric vehicles. Nexeon has Joint Development partnerships with a global consumer electronics company and a Tier 1 automotive manufacturer. In addition Nexeon has a number of Material Evaluation Agreements with Li-ion battery manufacturers.
One factor slowing EV and hybrid adoption is natural caution about adopting new technologies and the overall cost of the batteries required to power an electric vehicle. In this regard, presently the cathode material, electrolyte and separator are all relatively expensive materials within the conventional Li-ion battery. Nexeon is currently working on optimising the technology for this application.
interest in higher energy density batteries for military applications particularly where the soldier hasd to carry the host equipment (radios) and their associated batteries.
Higher energy density batteries based on silicon anodes also have potential for energy storage to support off-grid power systems.
NT: As a spin-out of Imperial Innovations how hard has it been to find the funding to support your work?
BM:We’ve been very fortunate with our investors. Led by Imperial Innovations, and strongly supported by Invesco Perpetual, they have supported us at each stage, raising £40m in 2011 and a total of £55m overall, and we are confident we have the funding to progress to commercialisation of our materials using the 250 tonnes per annum plant proposed. We’ve also benefited from some TSB project funding. Our technology has been recognised with a number of recent awards, which has been good for our profile. We won the Rushlight Award for Energy Efficiency 2012-2013, and we were included in The 2012 Global Cleantech 100 list, which focuses on companies which are likely to make the most significant market impact over the next 5-10 years. We were also shortlisted for a One to Watch listing in the 2012 Cleantech Connect awards, which recognises companies that show an exciting new technology combined with great commercial promise.
NT: Beyond the technical problems what are the economic and business issues that could hold back the acceptance and deployment of this technology?
BM: Consumers are more than ready for the benefits of higher capacity Li-ion rechargeable batteries, and overall rechargeable batteries have a strong
Other products which can benefit from silicon anode Li-ion batteries include consumer electronics such as laptops, cell phones, and power tools especially. Nexeon’s technology delivers benefits of longer times between charges, and support for brighter screens and load intensive applications. We are also doing further optimisation work in this area. Devices that require battery capacity to be held for long periods of time with infrequent or low power use, such as emergency lighting, defibrillator machines and pacemaker devices also benefit from silicon-anode Li-ion batteries. There is also
environmental acceptance over one time use non-rechargeable batteries. There is also a good economic case for battery manufacturers to adopt a ‘drop in’ approach with a new battery material such as silicon. The potential issues might be around the scale of production by Nexeon and the credibility of a start up company entering material production. On both of these points the recent strategic investment of Wacker Chemie will be a positive factor for Nexeon in terms of scale up and with the customers.
Nexeon |
www.nexeon.co.uk www.cieonline.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64