Hybrid battery

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A hybrid battery , named after its use, is a special accumulator that is used to store energy in hybrid vehicles . Power sources that combine different technologies, for example the combination of direct methanol fuel cells and lithium polymer batteries , are also named in this way, but are not the subject of this article.

properties

There are special requirements for hybrid drive batteries. With their small size, they must be able to release and absorb very large amounts of energy in a short time (performance-optimized) and should have a long service life at economical prices. Since conventional batteries available on the market, as well as energy-optimized (high-capacity) drive batteries for electric cars, are not suitable for this purpose, special batteries were developed for hybrid vehicles in the 1990s.

For example, the world's largest manufacturer Panasonic , together with Toyota , developed a hybrid battery based on nickel-metal hydride cells for the 1997 Toyota Prius . Nickel-metal hydride cells are protected by patents and were only produced by the American manufacturer Cobasys for vehicles from 10 Ah. Panasonic was sued by Cobasys and had to discontinue production of 95 Ah nickel metal hydride cells for the Toyota RAV4- EV and other vehicles. Before Cobasys was sold to a joint venture between Samsung and Bosch in 2009 , it was a subsidiary of the oil multinational Chevron , which retained the patent rights.

Other manufacturers, such as Automotive Energy Supply (AESC) , are developing special lithium-ion batteries for hybrid vehicles. With anodes made of amorphous carbon, these cells for hybrid vehicles are optimized for current load, so that high currents are possible with small cell sizes in drive support or recuperation .

With the current developments in lithium-ion batteries, too, the developers are faced with the conflicting objectives of aiming for either the highest possible energy density (high capacity, long range) or a high power density (high load capacity, lowest internal resistance, charging capacity). The best values ​​for all desired properties cannot be achieved at the same time. The use of a new traction battery with higher capacity in the Nissan Leaf led to the Rapidgate, since high-capacity cells usually have a higher internal resistance and therefore heat up significantly more at higher currents.

Both the electrode materials and the electrolytes are specially optimized and further developed for the purposes of use, whereby the areas of application of the different cells can overlap due to the characteristic data achieved today. In the Hyundai Ioniq of the first generation, high-current cells were used for the traction battery. Although this battery only had about 28 kWh of energy, it could be charged over a very wide range with high current (about 70 kW, i.e. 2.5C). The later model with 38 kWh energy content in the same housing only achieves lower charging rates (around 45 kW, i.e. 1.2C)

Individual evidence

  1. ↑ Innonet: Planar Micro Fuel Cell (PlanarFC) ( Memento from November 8, 2007 in the Internet Archive ) (PDF; 189 kB).
  2. ^ Cobasys Providing NiMH Battery Systems for Verizon Hybrid Van Retrofits . Green Car Congress, May 23, 2007.
    Further information on patent disputes at en: Patent encumbrance of large automotive NiMH batteries
  3. ^ AESC: Cell, Module and Pack for HEV Applications , Cell Specification, Diagrams , accessed July 8, 2013.
  4. ↑ Website: e-autos.de, Lexicon: Rapidgate , accessed November 29, 2019
  5. ↑ FastNet: Charging with a Hyundai Ioniq , accessed November 29, 2019