It's the Batteries, Stupid!

But Depew and Maguire are convinced that their company is at a disadvantage because it’s not close to the Big Three. And so it is no longer pursuing the $80 million. “We walked away from it because we didn’t think we could qualify,” Depew said. “Our batteries are not tied to a specific vehicle program, and we’re not trying to build a factory on an existing brownfield development site.” Maguire adds that the program seems to be geared to “helping the Big Three and subsidizing the incumbents—it’s not geared to startups.”

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Viruses have been used to help build batteries that may one day power cars and all types of electronic devices.

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The virus was coaxed into binding with iron phosphate and then carbon nanotubes to create a highly conductive material.

The batteries have the same energy capacity and power performance as rechargeable batteries used to power plug-in hybrid cars.

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TEG said:

World Best Battery Pack

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romeopapa said:

folks,

Sorry if the answer to this is posted somewhere else here....I couldn't find it.

does anyone know what density batteries Tesla is using? typical densities for these batteries are 2200mAh. Older cells are the 1800 mAh variety, and there are newer, more expensive, 2600 mAh ones available.

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Fortunately, all the conversion factors have already been calculated and we need merely to set up the parameters and run the numbers. We will start with a full charge and drain the battery of its theoretical capacity. In this case we will use 2.2 Ampere hour cells.

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...There is a huge difference in cycle life between a 4.2V/cell charge (defined by the manufacturers as “fully charged”) and a 4.15V/cell charge. 4.15 volts represents a charge of about 95 percent. For this reduction of initial capacity (5 percent), the batteries last a whole lot longer. Unfortunately, further reduction of charge has a much smaller benefit on cycle life. Understanding this tradeoff, Tesla Motors has decided to limit the maximum charge of its cells to 4.15 volts, taking an initial 5 percent range hit to maximize lifetime of the pack. We also limit discharge of our battery pack to 3.0V/cell and will shut down the car when the batteries reach this level. Limiting our charge rate is less of a compromise, since the wire size and availability of very high current outlets limit us much more than the batteries do at this point...

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Avoiding very high and very low states of charge. Voltages over 4.15V/cell (about 95 percent state of charge [SOC]) and voltages below 3.00V/cell (about 2 percent SOC) cause more stress on the insides of the cell (both physical and electrical).

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At higher charge states cells lose capacity faster. This is a second reason why we have limited our maximum state of charge to 4.15V/cell instead of 4.2V/cell. We also offer the driver the option of charging to only 3.8V/cell (~50 percent) or 4.10V/cell (~90 percent) to further extend calendar life if the full vehicle range is not needed on the next few trips. We advise and encourage a full (4.15V/cell) charge only when it is needed.

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Singh, who developed the nano-structured polymer electrolyte as a post-doctoral fellow at Lawrence Berkeley National Labs, says Seeo’s battery can deliver 300 watt hours per kilogram, compared with traditional lithium-ion batteries that normally operate with less than 200 watt hours per kilogram.

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