Lithium batteries leading electrochemical energy storage technologies

The number of patent applications for electrochemical energy storage technologies has skyrocketed in recent years, and most of them are lithium based, according to a new study by the Technical University of Munich (TUM).

The report, Monitoring Innovation in Electrochemical Energy Storage Technologies: A Patent-based Approach, offers a differentiated analysis of which energy storage technologies will be viable in the exit from fossil-fuel energy. It also offers a sobering assessment of U.S. and European battery storage development, pointing out that Western companies are "falling behind economically, as Asian companies apply for a substantially higher number of patents."

The report noted that as wind and solar power are inherently intermittent energy sources, excess energy will have to be stored during productive periods if large amounts of electricity are produced with renewable energy sources in the future in order to compensate for fluctuations.

A number of different electrochemical technologies are now competing to meet those growing needs.

"Knowing which technologies are the subject of more intensive development activities and will enter the market in the near future is strategically important to all stakeholders in the energy sector, whether from the industry, political sphere or science,” according to the report.

Since companies do not readily divulge their research and development activities, TUM researchers analyzed worldwide patent applications relating to electrochemical energy storage between 1991 and 2011 as part of a large interdisciplinary project on battery storage.

The study shows that the annual number of new patent families, i.e. groups of patent applications and patents for similar or equivalent inventions, including applications in different countries, rose by 110% from 2006 to 2011. In 2006, applications for intellectual property rights for around 2,800 developments were submitted. In 2011, the figure had already increased to 5,900 applications.

"In view of these investments, we can assume that new electrochemical energy storage technologies will be ready for market entry in the near future and will be more cost-effective than the existing products," says Simon C. Müller, physicist and economist at the TUM School of Management’s chair for Strategy and Organization.

Lithium segment very dynamic

Researchers found that most patent applications by far were filed by developers of lithium batteries: in 2011, there were 4,900 new patent families. Indeed, the curve for application numbers in this segment has followed a steep upward trend since 2008 after a single dip in 2007. Before that, several suppliers had had to take back products due to safety issues.

"Apparently, fears that lithium batteries cannot be made safe enough have vanished," says Müller. Moreover, the new patent applications are cited more often than other technologies by newer patent families — a mark of quality which shows that they play a role in the continued development of the technology.

In second place in terms of the number of patent applications filed are lead batteries with only some 580 new patent families in 2011. The researchers also noted a recent marked increase, albeit to a low level, for redox flow batteries, in which the energy-storing chemical compounds are used in liquid form: From 2009 until 2011, the number of applications more than doubled from 90 to 200. The number of new patent families for alkaline batteries dropped slightly to 240 and sodium-sulphur technologies played a consistently marginal roll with 20 applications.

"The lithium segment is very dynamic," Müller adds. "Quite possibly, we will soon reach a point at which a self-multiplying effect can be seen. As soon as the techno-economic data are good enough, research and development activities will attract more investments, which will generate an even stronger lead."

The fact that lithium batteries are also used in electric cars will only contribute to this development, since batteries will be in demand both in the energy sector and in the automotive industry.

Asian developers submitted almost four times as many patent applications as European counterparts

The analysis indicates that Asian companies will dominate the market. In 2011, 2,100 applications for patent families relating to electrochemical energy storage were attributed to Asian developers; 530 to European, and only 410 to U.S. developers. Despite a high initial figure, Asians were able to increase their applications by 220% since 2001, while European applications rose by 260% and U.S. applications by 70%.

If one considers the quality of the portfolio, Asian companies still hold a very dominant position, according to the report. Researchers used an index that took both quantitative data and the number of application citations into consideration. According to this index, the top 10 in the lithium batteries segment include eight Japanese and one Korean company, with Fuji in the lead. Only one U.S. company, Valence Technology, made it on the list. The most successful European institution, Centre National de la Recherche Scientifique (CNRS), is only ranked 25th.

"These results raise interesting questions about research policy and development management," says Prof. Isabell M. Welpe, who holds the Chair for Strategy and Organization. "Further studies could, for instance, look at which strategies have given certain companies a technological lead in this field, and which lessons may be learned from this by European and U.S. competitors."

The study is part of the EEBatt project, which focuses on decentralized stationary battery storage for an efficient use of renewable energy and support of grid stability. Funded by the Bavarian Ministry of Economic Affairs and Media, Energy and Technology, the project jointly run by TUM, the Bavarian Institute for Applied Energy Research (ZAE Bayern) and VARTA Storage GmbH.