I am terribly sorry for your woes and take comfort that no one was hurt and that the damage was kept to a minimum. I do not want to sound conceited here however several key elements in this discussion have been missed.
Joyetech electronic cigarette Tank System Changeable System eGo-C eGo-T 510-T e-Liquid this is what Joyetech sells, if it is not listed on their site, it is a clone a knock off, pure and simple.
Joytech does not sell a 600mAh battery - they sell 650mAh batteries. If it was a typo then fine if not, I have never heard of a 600mAh eGo battery in the 2 yrs that I have been using the product.
One of the reason Joyetech paid there vendors to sell off (sale) all non-branded JoyE product last fall was to clear their reputation which was/has been tainted by the eGo brand.
BTW FC Tornado is a Joyetech product but the Riva and Kgo are not. I was offered and eGoC kit (unboxed for $5.10 minus chargers) <--- this is a bogus product as the eGo C wholesales for far more than that. If it is too good to be true, then it is.
If I am not mistaken Joytech batteries are charged at the factory to 85% and are ready to go out of the box. The kits come complete with a DC input 5V 500 mA charger with an output of DC4.2V 420mA this charger is to be used with the 650mAh batteries whilst the 450mA is designed for the 900 and 1000mAh batteries. Any respectable vendor will have / should have this information posted on their site.
There has been a couple of incidents where un-corded chargers were used to charge batteries with similar results of the OP. Their outputs are 5V 420mA. As can be seen, the specs clearly indicate the battery is going to go BOOM on the fist charge, and they have.
Just because it says eGoT on the battery, it doesn't mean it is a Joyetech battery, hence why the massive sale of unbranded product. My first two eGo kits saw me through 14 months for 2 time batts, 15 months for 1 x batt, and one that failed after 6 months. To me that is an excellent track record. BTW I never vaped LRs or DCs on them. Yes many folks claim they have been doing yadi yadi yada. The Mofset in the batts is what goes, once it goes the battery is unusable. Same thing happens when a carto or addy causes a dead short, it fries the Mofset, and battery no longer works. LRs were designed to be used on LiMn (IMR) batteries of 420mAh or better, or a LI Ion battery with similar specs to the IMR. Does the avg individual know that an eGo batt spikes to 8.6V on it's first duty cycle?
IMO abusing your batteries using LRs or DCs where one is not supposed to, creates internal resistance in the battery, or what is known as rock content (depleted material unable to further accept a charge) This internal resistance grows exponentially with time, to a point where a battery simply quits working or in some cases may actual fail with prejudice (boom). Fast charging a battery in this state (eGo charger 420mA) can result in catastrophic failure of the battery as too much current is being delivered. Should the PCB on the battery fail, you are basically charging an unprotected battery.
I cannot re-iterate enough that folks need to keep track of their charging times, and usage times - both will decrease over time. Initially it should not take 2.5hrs to charge an eGo battery, maybe, just maybe 1/2hr tops (brand new, never used batt). As internal resistance (as the battery normally depletes) charging current is decreased to meet the demands of the battery, and your batteries take longer to charge (initially). As internal resistance increases and hence less material capable of accepting a charge, charging times will shorten. This is the sign you need to be looking for new batteries.
We are quick to blame the Chinese for our failures and rightfully so, OTOH a lot of incidents could have been prevented IMMHO and can be pointed to user error, intentional or otherwise. The latter is not uncommon when newbies accept the advice from another newbie. This si the driver's manual I invite eryone to read it
Basic to Advanced Battery Information from Battery University
In closing, several vendors will be stocking LiPO charging sacks. These will protect your home and you in the event of a catastrophic failure. OTOH it is up to each and everyone of us to learn how to use these cells responsibly.
To the OP once again I am glad nothing further happened and as many have stated we believe the charger to be the culprit here. Just because it worked (or may not have actually) with other batts does not mean it can with all. Always use the charger that came with the kit, do not interchange. Some chargers and batteries have their poles interchanged +/- charging normal batteries with standard poles is asking for an accident to happen.
Did I sound like a Joyetech fanboy? Yup! was it intentional? Nope! But I only buy quality product because it has served me well in the past. BTW eGoT LCD, both batts failed withint 6 months, one was four. I don't believe it to be user error with my track record - just a sub-quality product.