Lithium Battery Industry in a Dangerous Explosion, the International Accident

characteristics to installation in explosion hazard areas. These

requirements are necessary to avoi d a n explosion caused by

switching operations. When th e SPD are installed in explosion

hazard areas, they need to fulfill two diff erent requirements.

Conduct the surge currents, avoiding the ignition in t he explosive

Surge protection and the explosion protection are b ased in

similar concepts: The division in specific zones. But the zones

in lightning protectio n SPD are designed based in technical

and the testing methods. But these methods do not consider the

existence or not of explosive atmo sphere where the SPD will be

installed. The ligh tning zones are different of the expl osion

hazard zones. In this case it is necessary that the SPD project to

consider two completely diffe rent requirements, and w ill be

necessary to know how to project a device capable to conduct a

very high electrical current, to avoid the ignitio n of an

This paper wil l to analy ze separately the requirements f or

lightning and ov ervoltage protection, and the requirements for

electrical devices installed in explosion hazard areas. After that

will be p ointed how to develop a project for an SPD to be

An electrical system is pro tected against surges if a ll energy and

data cables connected to the components' system are integrated

into the equipotential bonding sy stem at lightning protection

LPZ 3 Zone inside the building (can also be the metal ho using of a

consumer). No interference pulses through L emp or surges

The lightning protection zone concept is described in

international standard IEC 62305-4. This concept is based on

the principle of gradually reducing surges t o a safe level in

bonding in accordance with DIN VDE 0185-3 f or direct

0100-443 for surge voltages arriving through t he supply

- Installation e.g. in the power distributor , sub

Surge protection devices are classified in acco rdance with

IEC 61643-11 into three type classes: Type 1, Type 2 and Type

3. This classification enables the SPD to match different

requirements with regard to location, protection level and

current carrying capac ity, at point where it is installed.

Explosive ar eas are divi ded in to zo nes. The division into

zones is a method to analyze and classify environments in

which explosive gas atmospheres or dust/air mixtures may

occur. This can simplify the selection o f d evices that ca n be

operated safely in these environments. The hazardous areas,

which are created by combustible gases, a re di vided into the

zones 0, 1 and 2. Hazardous areas, in which combustible dusts

are created, are, in the same way, split into the zon es 20, 21 und

22. The risk potential i s higher in zones 0 and 20 and the lower

in the zones 2 and 22.

areas, have the same electromagnetic behavior. Beside the Ex-

proof areas are classified in function of the presence of

The subst ances can to be present in anywhere, but more

risk. The installation panels have space enough t o put inside a

normal SPD, in this case the panel and not the SPD needs to be

In other situations where S PD Ex-proof needs to be install ed

it is necessary develop sur ge protector without the risk of

sparking and that don' t increase the external tem perature.

How large would these explosions be?

No a suitcase size bomb can not do that from what I've heard. It can spread deadly radiation over a large area but the explosion would not take out Metropolitan DC.

Choosing a Tantalum based on Min. ESR - LDO Stability

Tantalum capacitors have an oxide film grown on the tantalum metal to serve as an electrolytic barrier. This layer is very (very very) thin and can be punctured by voltages only slightly above rated voltage. If it is punctured it does not self heal. If there is enough energy to cause a minor thermal event then the capacitor will oblige and will self destruct with some or all of flame, smoke, smell, noise and explosion. I've seen one do all of these on the same occasion. A very short voltage spike - even in the microsecond range - can start this process. Instead, use solid Aluminum or ceramics. Lots of material on solid Al caps. Halt and catch fire !!! - a 16V tantalum run on 20V !!!The photo below is "cheating" in that they used reverse polarity BUT you can get effects every bit as "good" just by using slight overvoltage