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Raymond Bonnaterre
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A 8S very big Li-Ion LVP65 cells (75Ah x 3.7V x 8) battery without circuit-breaker (of course) on each single cell is not obviously a nice choice for an aircraft battery and to prevent thermal runaway phenomena. It's may be time for Boeing's subcontractors to comme back to a traditional two 24 Volts Nickel-Cadmium batteries solution or a more sophisticated Serie/ Parallel design with smaller prismatic Li-Ion cells . It's a necessary long way to go!
2C + 2H2O ----> CO2 + CH4 30 bcm CH4 and 30 bcm CO2 together or 60 million tons of CO2 per year for a small "bluegas" chinese unit.
A non event for others sources:
The EV battery business is generally a close financial and operational relationship between one battery producer and one or two cars manufacturers. It will never be a commodity open market, as small cells or batteries for phones or lap-top computers. So, to predict overcapacities in 2015 seems to me a little bit stupid theory.
Simodul, Hydrogen is coming from methane in a first step and water in a second one, to convert CO in CO2. So the global reaction is not so bad with 3 H2 molecules from a single CH4. But CO2 emission is the price to pay for a low sulfur amount in your gasoline. Difficult choice!
Henrik, 1) Energy lost as usual gives heat (your battery is warmer after pulse)due to battery resistance. 2) The game to get the minimum resistance in a battery is to reduce electronic and ionic resistance. Electronic resistance is reduced by using larger or thicker current collectors (Aluminum for positive electrode and Copper for negative electrode). Ionic résistance is generally obtained by increasing surface of electrodes and reducing thickness. Larger is the surface lower is the current density in the electrolyte, where ionic charge transfer occurs. Generally a battery design is a compromise between energy and power. Higher power performance reduces energy density and increases cost. For a big and compact EV battery, a low internal resistance reduces heat generation and battery average temperature. It's a good way to increase cycle life.
Henrik, for the maximum 30 seconds 1200AMP peak current battery voltage is not 3.7V but 3.7V/2. Because power equation for a battery is: P = (Eo - rI)I then dP/dI =Eo- 2rI The parabol curve maximum occurs for I=Eo/2r or V= Eo/2 Then Pmax= 217.5 kW . It's a pretty good value with a battery internal resistance around 16 mOhms. In fact 1200AMPS is a 40C rate of discharge. This type of value, for 30 secons pulse, is usual in aircraft Ni-Cd batteries to start the APU.
Note : 3.5 millions cells per month in 2010 will be equivalent to 500 000 Insight type 101V (84 cells) battery packs per year.
To follow the story please open the link to GCC following page: Quality in carbon coating is a key point to prevent, inside the electrode, spot local high current density, inhomogeneous cristallization and to get longer battery cycle life and higher discharge voltage. Japanese battery industry subcontractors are surely working a lot on the subject! A very sophisticated positive material is definitively needed to define a long life LiFePO4 battery.