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Exclusive interview with the German VDA: Battery cell standardisation

13 April 2011

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The German Association of the Automotive Industry (VDA) unites the manufacturers and suppliers in the German automotive industry. has talked to Hans-Georg Frischkorn, Managing Director of the VDA, about the association’s efforts in defining standards for lithium-ion battery cells.
VDA is working on standards for lithium-ion battery cells. How many different battery cells are there today on the market?

Hans-Georg Frischkorn
: As far as lithium-ion cells for automotive usage are concerned: We currently have three basic construction types - cylindrical cells, prismatic cells, pouch cells. In respect to their production process and for the later system design all three design types have different advantages and disadvantages. Are you focusing exclusively on the standardisation of lithium-ion battery cells or will the standards be valid for any kind of battery cells?

: The current standardisation project is focused on lithium-ion cells exclusively. If market needs and technologies will change in the future, the establishment of new standards for other kind of cells will be possible. From which angle did you start defining standards for battery cells? What are the aspects you are focusing on – i.e. energy density, discharge rate, power level, lifetime span?

The proposed standard will define cell dimensions and not requirements for technical features (i.e. material usage) or technological features (i.e. energy density, lifetime cycle or charge and discharge rates). But the application does have influence on dimensions. So when we talk about the question of dimensions, there is a need to distinguish between high power applications (i.e. BEV, P-HEV) and high energy applications (i.e. HEV). What is the greatest challenge in defining these standards?

Actually, there are quite a few suppliers of cells. These cells have different dimensions, and the location of the connection terminals is different, too. There are a lot of pros and cons for each design. The aim would be to achieve standardised dimensions which combine the pros of the different designs and eliminate most of the cons. What will be the greatest benefit of having these standards?

: The standard is driven by cost reduction. The battery system is one of the most expensive systems of a vehicle with electric propulsion. In the interest of the user, it is necessary to decrease these costs. Scale effects are always useful. If you take the price reduction in recent years after the batteries for standard notebooks have been standardised, you can tell what a standardisation agreement will do to the price – and to the market. In contradiction to that, battery prices for cell phones are stagnating, since each cell phone type still requires a different battery design.

Getting back to cars: In addition to the scale effect, standardised dimensions will allow a more clear-cut competition between the cell suppliers while the system manufacturer will be able to change the cell supplier after the battery system design has been finished. Is it wise to standardise batteries cells considering that great improvements in battery technology are expected in the next decade?

: The improvement in technology might happen, but will also take time. New technologies need to be proven in long-run tests and adaptation loops. The same accounts for notebooks, but as we can learn from the market, a proven technology will be in use for a very long time period. This is especially true for vehicles, were the lifetime is even longer than it is for notebooks and cell phones. Can the standardisation of battery technology become a barrier to innovation?

: The current technology for lithium-ion cells in respect to the outer dimensions of the different cell types is relatively stable. To get battery powered vehicles in the market, we need affordable prices. Standardisation is the right way to achieve this. Otherwise the user will stick to the existing technology with combustion engine driven vehicles. Waiting too long would endanger the entire progress of e-mobility. How do you see the battery market evolving over the next 5 to 10 years in terms of technology, price, and production capacity?

: There are a lot of studies available for such estimates. It would be no help to add any further estimate. It depends on so many factors that a proven forecast is very difficult. However, we do expect an expansion since we believe in the future of electric vehicles. With whom have you worked together in the definition of these standards?

: Standardisation is always open to all stakeholders. The German automotive manufacturers provided the first draft for this project by consulting suppliers and system designers before. This first draft was a necessary initial step to start discussion and the standardisation process itself. Now the international standardisation project has been approved in March 2011. This means all interested parties are invited to join the development and to comment on the future drafts. In Germany, the DIN Standardisation Institute has already published a DIN Spec (pre-standard) for lithium-ion cells based on the German initial proposal. For when do you foresee the publication of these standards?

: Standardisation follows strict rules to ensure consensus of all interested stakeholders. There are given periods in which the drafts are open for public commenting. There are also different ways or forms of publication to shorten this time. The goal is to get this standard out as fast as possible. The kick-off meeting for the international standard is scheduled for June 2011. A first public available draft could be expected end of this year or beginning of next year. How do you evaluate the chances of these standards that you are working on becoming an internationally accepted standard?

: It is yet to be found out how strong the support on international level will be. Up to now, we have received some feedback showing good support. It is difficult to forecast the discussion and the number of different opinions. There is a flexibility to choose other publications forms if the ongoing discussion will face the developers with difficulties to get full consensus. Can you give us a short overview of what is happening on an international scale in terms of standardisation work for EV batteries?

: Automotive manufacturers are selling their products worldwide. They are interested to work on the basis of international standards instead of applying their products to a large number of regional or national standards. Therefore, the automotive industry prefers to go for one international standard only. Deriving regional or national standards will lead to higher costs.

One more point: Beside this on-going activity on cell dimensions, there are standards under development for the testing of battery systems and cells. This is done to provide equal test procedures to ensure comparability of the test results. These standards are going to be published soon. Furthermore, based on these test specifications, requirements for safety are going to be standardised also. Mr. Frischkorn, many thanks for your answers!


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