There are many forklift makes that use battery restraints as standard equipment on all their models, either due to the design of the hood (Toyota 5 series with latch) or through use of a removable bar that is chained to the truck so it cannot be removed (Toyota 2 and 5 series three wheeler).
In Canada,
Safety regulations stipulate battery retainer mechanisms are mandatory for mobile equipment.
I once witnessed the aftermath of a forklift that rolled backwards off a dock and landed on its overhead guard upside down, the battery weight was too great for the battery cover and busted the hinges and slammed into the overhead guard, squashing the driver's seat to about 30mm thick and then leaking battery acid over everything.
If the young operator had not jumped clear he would have looked like stawberry jam squashed under that 3000 lb battery.
This concludes my lesson on "Battery Retainers 101".
I have seen the photo you mention and have innocently assumed the batteries had come out due damaged caused during the accident, as you suggest probably not so.
I find this situation remarkable, the batteries are heavy, full of acid and likely to squash and burn for all of the above reasons.
In the UK all road vehicle batteries are required to be secured for annual testing purposes, clearly vehicle batteries are always much smaller and lighter.
How can this be permitted?
To ROD_S
If you have a look in the Photo Galleries under Incidents & accidents you will see an electric "Trike" that has been rolled,
beside it you will see the battery box that has been ejected and the batteries that have come out of the box.
I do not wish to give the impression that I am criticising the brand depicted and I do not wish to name other brands because a simple quick look will surfice.
It is hard to believe that there is no provision for retention of the batteries, on any vehicle. Certainly batteries must be secured on any road vehicle in the UK/EC.
Is it possible to check with the manufacturer that nothing is missing/modified on this truck. Perhaps you could let us know the make & model so that other visitors can check their trucks?
Do you have a Government safety organisation you can refer the matter to in the event that this truck is "as supplied"?