Q:

With today's technology, is it possible to charge a battery over 100% without exploding? 

We all know who Iron Man is. 
Hollywood makes a nice job to make him look like a genious in electronic. 
However, there is a scene where his suit charges it's batteries to 475%. 
There is another question, on another website, adressing one part of this issue. 
You can read it on Can Iron Man recharge his suit from lightning?. 
What I'm asking here is if it is possible to charge a battery (no sci-fi stuff, please), with current technoligy, to over 100% of it's charge without exploding? 

A:

Well if you say 100% is the capacity of the battery specified by the manufacturer, then yes nearly all batteries are charged beyond 100%, as the manufacturer will indicate the minimum capacity, so they are not made liable for any failures concerning too little capacity. 
But that's in the range of maybe a few percent and not a massive 375% or something like that. 
The reaction to overcharging the battery is very dependent on the chemistry involved.  Some will tend to explode (lithium ion and lithium polymer), others will just waste the additional charging current to heat. 
The point made by PlasmaHH in the comment is actually a quite good one.  If a battery could hold significantly more charge as advertised, the manufacturer would be quite dumb.  Now you could argue, that a lot of ICs will also run at much higher speeds than advertised.  But on closer inspection, not all ICs are able to, and that's why manufacturers turn the speed down to a level where every chip runs - it increases the yield and thus you can make more money.  Batteries seem to behave more predictable for manufacturing. 
Maybe a capacitor can handle more voltage and so store more energy than advertised.  As the energy stored on a capacitor increases with the square of the voltage, you would need to double the voltage to store four times the energy. 
That doesn't sound too bad actually - you might find some capacitors which are able to handle double the voltage specified as they are tested quite hard.  But then the energy stored on capacitors is quite low compared to batteries. ( There are massive capacitors, but you wouldn't want to carry one around)

