Fabrizio Marzolini – Lithium-ion technology is going to revolutionise the battery industry, but that’s not all

Energy storage, more specifically the storage of its most refined form, electricity, has for decades been the subject of disagreement in the automotive and electricity production industries. The cost of storage and received ideas based on the poor reputation of lead and nickel cadmium (NiCd) technologies are arguments put forward with a view to limiting battery deployment. Lithium ion (Li-ion) technology has now become a credible alternative, enabling economically viable solutions to be offered. A number of excellent commercial applications have emerged in the personal and commercial transport markets, and in the integration of renewable energies.

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Fabrizio Marzolini

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Lithium-ion technology

Lithium-ion technology is going to revolutionise the battery industry, but that’s not all

Energy storage, more specifically the storage of its most refined form, electricity, has for decades been the subject of disagreement in the automotive and electricity production industries. The cost of storage and received ideas based on the poor reputation of lead and nickel cadmium (NiCd) technologies are arguments put forward with a view to limiting battery deployment. Lithium ion (Li-ion) technology has now become a credible alternative, enabling economically viable solutions to be offered. A number of excellent commercial applications have emerged in the personal and commercial transport markets, and in the integration of renewable energies.

Li-ion technology has been around in its commercial form since the late 1990s, and it has found its natural place in mobile applications. The successful development of the mobile phone, social networks and connected devices has owed a considerable amount to the availability of Li-ion batteries on the market – in fact, the battery has made a significant contribution to the digitisation of our society. Long disparaged as a technical impossibility, electricity storage has become reality. For a long time, the storage density of lead batteries (40Wh/kg), their low energy output of 70% and the impossibility of recharging in less than an hour prevented the development of electric vehicles and stationary applications such as those in electricity grids.

Digitisation plays an essential role in recent developments by ensuring the integration of batteries in stationary applications, since it is the only tool that enables the incorporation of non-flexible electrical infrastructures with photovoltaic generators and wind turbines, which are by their nature very volatile.

Building blocks for resolving the density problem

Unfortunately, this technology has its limits and still needs to evolve. Although the energy density of Li-ion (200 Wh/kg) is five times greater than that of lead, it is still weak in comparison with that of a litre of fuel (10,000 Wh/kg). Furthermore, first-generation Li-ion batteries were not designed for the construction of large-capacity batteries. Large energy capacity means storage levels of several tens, hundreds or thousands of kWh, the scale needed to meet the needs of an electric vehicle, a hybrid solar power plant, a ferry or an infrastructure for the control of an electricity grid’s primary reserve. By way of comparison, a mobile phone stores around ten Wh. Tens of thousands of these batteries would therefore be needed to power a bus or an electric boat. While this would be possible, the integration of small cells is not a preferred solution.

The battery industry has chosen to develop cells of sizes adapted to these markets, and in the last few years, cells with an energy capacity approaching 200 to 300 Wh have been produced, making it easier to integrate them in modular solutions, as building blocks that can be assembled to form systems appropriate for the end application. This results in optimised modules that meet the requirements of an application, which are integrated in standardised racks for electricity grid applications or on chassis equipped with heat exchangers for electric vehicles. Each of these systems has a management system to ensure its safe use and performance maximisation.

For a company such as Leclanché, a manufacturer of alkaline and lead batteries until 2006, these developments meant a radical change of focus. Li-ion technology is known by all today, but this was not the case at all 15 years ago. In 2018, to offer a Li-ion storage solution, which involves both producing and integrating the cells, means being skilled in areas including electrochemistry, the production and transformation of chemical substances, electronic engineering, mechanical engineering, electrical and thermal engineering, software and firmware aspects, bus technology for communications, client application modelling and simulation, project management and the sale of turnkey projects. The information, control, algorithms, services and monetisation epitomised by digitisation is the Holy Grail of energy storage.

The battery, an investment and a connected service

To conclude, as storage capacities get bigger, the battery is no longer considered a consumable, but an investment. The battery may only be sold if the service it provides is within a viable economic framework. Financial modelling is therefore essential to make sure that batteries meet the needs of the renewable energy or commercial transport markets, to name but two.

The cost of installed kWh is thus no longer significant in battery comparisons; the true cost to be considered is the TCO (total cost of ownership), including: the system that comprises the battery, the integration equipment, electrical protection devices, energy conversion, auxiliary equipment and the management software, together with the energy management software (EMS), which by virtue of its algorithms may significantly improve the performance of the system and increase its yields.

In its capacity as storage system, the battery offers a service that will pay for itself either in terms of the energy or the power it provides to its application. Storage systems will increasingly be sold in the form of a service in order to avoid the problems associated with investment, moving towards an operations-based concept. This is a new paradigm which needs to be considered for this kind of system, because this constraint did not exist in the case of portable devices equipped with Li-ion batteries.

About the author

Fabrizio Marzolini joined Leclanché in 1994 as an electronics engineer, and is now Executive Vice President of the Specialty Batteries BU. On the basis of experience gained from setting up a business unit with the mission of providing energy storage solutions for mobile phones and robotic applications, and drawing on his extensive knowledge of Li-ion batteries, in 2015, he established an international structure for the development and deployment of storage and energy conversion systems on a scale appropriate for electricity grids. Examples include the EPFL project and the installation on the Graciosa Island.