Why does 2x the volume of batteries = more than 5x the capacity?

[cornfieldcraig]

The FFH has a 1.4 Kwh battery.  The FFE has a 7.6 Kwh battery.  The FFH has roughly 4 cubic feet less trunk space than the standard Fusion.  The FFE has roughly 8 cubic feet less.   I know there's ventilation in there too, but I don't know how that differs from the FFH to the FFE.

 

Based solely on volume it would seem that Ford made two layers of batteries instead of just one.  If that's the case, then how is it that  2x of battery volume results in 5.4x the electrical capacity?   I wonder if the charging system treats the entire HVB as a single battery or if it handles it like 2 separate batteries -- one layer for FFH-like mild hybrid mode and the other for plug-in, full EV mode.  If it manages them separately, then I'm guessing that the FFH batteries are overspec'ed in order to ensure sufficient capacity for 100k+ miles.  

 

My brain hurts.

[Rexracer]

Who says that the battery in the Focus is ONLY taking up space in the trunk that would normally be usable? There are lots of nooks and crannies in cars that are not usable that could be used to shove the larger battery.

 

My guess (only guess) is that the battery is physically larger, and also can take better advantage of the battery with its liquid cooling. Also we know that batteries with the same physical size can have different capacities (look at normal car batteries). The easiest example I can think of is RC car batteries.

 

for example this 5500mah battery

http://www.stormerhobbies.com/cgi-bin/seekpart.pl?src=ns&pn=ASC0739

 

vs this 7000mah battery

http://www.stormerhobbies.com/cgi-bin/seekpart.pl?src=ns&pn=ASC0309

 

 

I have batteries that are this exact same physical size down to 3000mah, and I know they go up to 9000mah.

 

So beyond physical size, the chemical makeup of the batteries could be completely different. My hope for the future, as batteries improve, that we can get to the point of a "standard" battery, that we can swap out at will, and take advantage of ever improving technology. Like in 5 years I hope to be able to purchase for about 2k a battery that will give me a 40-50 mile range for my car.

Thats my hope.

 

And this is all my speculation.

Edited March 20, 2014 at 05:12 PM by Rexracer

[cornfieldcraig]

I didn't say anything about the Focus, unless you interpreted FFH as Ford Focus Hybrid.  I was only comparing the Ford Fusion Hybrid (FFH) to the Ford Fusion Energi (FFE).  If there are hidden battery locations in the Fusion Hybrid, then the added batteries in the Energi would only increase the ratio of volume to kWh.  

[Russael]

I think he may have interpreted the FFE as Ford Focus Electric.  I see that acronym on that forum. :)

 

As far as the difference in the physical pack size between the Hybrid and Energi goes, I'd assume they have different capacity cells.  Not only that, but part of the Energi trunk volume is also being taken up by a battery charger, and there's a large steel cage to protect that pack as well, both of which the hybrid does not have.  They both do contain the step down power converter to go from the pack voltage down to 13.8v for your 12v accessories.  They also both have ventilation, but the Energi one is more complex (and visible) with the ductwork.

 

The only thing that makes sense is different capacity cells.

[shaggy314]

And if you watch the lovely video, Ford's engineers shoved the battery in the trunk, high fived because it fit, and went home. While I'm sure they are smart people, it was bad consumer design.

[Rexracer]

I didn't say anything about the Focus, unless you interpreted FFH as Ford Focus Hybrid.  I was only comparing the Ford Fusion Hybrid (FFH) to the Ford Fusion Energi (FFE).  If there are hidden battery locations in the Fusion Hybrid, then the added batteries in the Energi would only increase the ratio of volume to kWh.  

Yep i just read your statement wrong, I thought you were talking about the Focus.