Evolving capacitor technologies

Evolving capacitor technologies
EEStor has recently developed an innovative solid state electrical storage technology that aims to initially disrupt the current US $4.6bn ** (~€3.93bn) aluminium electrolytic capacitor (AEC) market © istock Birdlkportfolio

EEStor’s Ian Clifford and Bryan Kelly tell SciTech Europa about their new innovative solid state electrical storage technology that aims to initially disrupt the aluminium electrolytic capacitor market.

EEStor Corporation’s mission is to be the provider of leading edge, solid state electrical energy storage and related technologies. The Company operates on the principle and belief that a fundamental breakthrough in energy storage will be the catalyst for positive environmental and economic change globally. The company has recently developed an innovative solid state electrical storage technology that aims to initially disrupt the current US $4.6bn (~€3.93bn) aluminium electrolytic capacitor (AEC) market. The hybrid capacitor dielectric material – glass-CMBT – has been shown in independent third party testing to provide higher permittivity at a significantly reduced cost to existing capacitor technologies.

Speaking to SciTech Europa, EEStor’s CEO, Ian Clifford, explained that the fundamental breakthrough needed to catalyse the aforementioned change stems, at least in part, from the global necessity to move away from fossil fuel dependency.

“That’s a global environmental issue that can’t be understated,” he said, adding: “We now can generate electricity, and sustainability utilise it – solar power is now the lowest cost electricity there has ever been historically, and perhaps the biggest issue in the area of renewables is now to create ‘fit for purpose’ energy storage solutions. If you have no way of storing the energy you are generating, then you have no way of controlling time of use or distribution through the grid, for instance.”

Global implementation impact

In light of this issue, one of EEStor’s primary focuses is on the development and commercialisation of grid-level storage solutions that are scalable, low cost, and can have global implementation impact.

As Bryan Kelly, EEStor’s Vice President for Production, told SciTech Europa: “the development of capacitors has stagnated somewhat in recent years, and while some minor improvements have been made to decrease the size and increase the energy storage capacity of current dialectrics:ceramic capacitors, which are built around barium titanate, aluminium electrolytic capacitors, which are built around aluminium oxide layers, have high surface areas, while film capacitors – which have very low dialectric constants – are big and bulky but do have very low dissipation factors.

“By mixing some of our dialectrics together you get a different product that has higher dialectric constants and higher voltages and allows us to approach grid level voltages efficiently and cost effectively.”

Turning his attention to new energy storage solutions, he added: “There are a lot of energy storage solutions on the battery side that we know about, but most of these have recycling problems and are typically toxic. We are therefore trying to get away from that by making a new generation of capacitors.”

The hybrid capacitor dielectric material (glass-CMBT) developed by EEStor has higher permittivity at a significantly reduced cost to existing capacitor technologies. However, this evolution posed several challenges during the development stages. Clifford explained that one of the most significant stemmed from the fact that the original intellectual property (IP) was based on a completely ceramic product, making it difficult to develop a lower cost, room temperature solution.

“That took time to perfect,” Clifford said. “We have now got several different polymer CMBT composites that can compete very well, and we have also advanced the ceramic programme to show we have unique capabilities in the marketplace in that regard too.”

Of course, miniaturisation is something which affects almost all technology areas and applications, with consumers demanding smaller and more powerful devices. And while this is not an issue when it comes to grid level storage, it is about scale rather than miniaturisation; but for capacitors in technology applications such as mobile phones – which, Clifford explained, contain several hundred discreet capacitors – then miniaturisation is key. EEStor’s technology can thus “go down to the micron scale effectively and with consistent performance, or up to large scale formats utilising the same architecture, which is quite unique to our product,” he added.

Large scale manufacturing of capacitor technologies

While the hybrid capacitor dielectric material developed by EEStor has potential in a range of sectors, the company’s business model is not to go into large scale manufacturing on its own. Rather, they have designed their model around licensing specifically. Clifford explained: “We have broken down our applications into particular vertical markets, including aluminium electrolytic replacement, decoupling capacitors for circuit board type applications and processing, and a number of other discreet markets.

“Currently, we are speaking with particular manufacturers around licensing the technology in these specific vertical markets. And some of them work on multiple lines, and we are therefore looking at how we could effectively license across multiple vertical markets as well.”

Additionally, EEStor is also considering ways to scale up the manufacturing and processing of composition modified barium titanate, which is the core material of their technology. Clifford said: “In Austin, Texas, USA, we have a fully-operational pilot production facility for CMBT production, which was designed with scaling in mind. In this sense, the ability to move from pilot level production to mass production is built into our development process.”

From a raw materials perspective, which it is important to consider when comparing energy storage technologies, Clifford went on to explain that barium and titanium materials are “globally prevalent, very low cost, and non-toxic (they are essentially environmentally inert), and widely available. In comparison, there are significant availability and toxicity issues for lithium, cobalt, and tantalum, which are also used in capacitors within energy storage technologies.

As such, EEStor’s capacitors are able to sidestep many of the more significant challenges experienced by more traditional capacitor technologies on the market today, and the company is now looking to partner with the smartest, most aggressive companies it can find which are looking for solutions and which already have global manufacturing capabilities and global distribution.

Market disruption

Licensees of EEStor solutions will, Clifford said, go on to disrupt the massive AEC and decoupling capacitor markets, and for Kelly, EEStor’s technology will be able to replace aluminium electrolytic capacitors in a lot of their applications due to the higher energy yields, higher dialectric constants and very low dissipation factors. “Our hybrid dialectric are also cheap to produce because they are much smaller,” he added.

In the decoupling market, Kelly went on, EEStor’s solutions are lead-free but still maintain a high capacitor per unit volume, meaning that they are also more environmentally friendly than their counterparts.

On the grid side of things, Clifford added: “lithium polymers are emerging which can offer 150-200 watt hours per litre, while lead acid can offer perhaps 50 watt hours per litre (or less when you factor in inefficiencies). And while there is a lot of talk now around solid state lithium ion or lithium polymers, these use an electrolyte which is either in solid or gel form, rather than a liquid. Yet, the cost effectiveness of these technologies is yet to be proven, and there are still issues around electrolytic reaction and ultimately the degradation of the storage device over its useful lifetime. With our technology, which is pure electrostatic, the testing we have done has shown that there is no degradation, meaning that we are able to offer a permanent energy storage solution.

“Even if the volumetric efficiency is an order of 10 different between our technology and the chemical technology that is now available, the good thing about most grid storage is that it is not real estate limited, meaning that it is possible to have larger storage devices that are true solid state, true lifetime, non-toxic, and low cost.”

The future

Moving forward, EEStor’s main priority will be to further its licensing activities, as well as to continue to improve their technology. Clifford commented: “We rely on third party independent validation of the technology for publication and certification purposes, and so that is an on-going cycle. We are ready to begin our phase nine tests, which will show dramatic improvements over the previous phases.”

The interest and emphasis on grid solutions is significant for the company, and the benefits of EEStor’s tech is that high energy densities are not required to make an incredible and significant impact in this area, meaning that there is little doubt that they will go on to disrupt the aluminium electrolytic capacitor market, and others, in the near future.

Ian Clifford
Bryan Kelly
Vice President for Production

This article will appear in SciTech Europa Quarterly issue 28, which will be published in September, 2018.

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