The choice of battery chemistry, standards and responsibilities

By Régis Prosper, Cartoni France

par Cartoni France Contre-Champ AFC n°327

[English] [français]

The generalization of the use of batteries and in particular the arrival of MEUs (mobile electric units) which are gradually replacing low-power groups pose several problems which requires reflection when choosing the chemistry of batteries.

Fire Risks
Lithium-Ion battery fires are becoming a reality on set, and it is essential to ensure that MEUs are certified. Indeed, in the event of a claim, the insurance expert will ask for the certification documents (CE, UN, electrical (EN) EMC ...) and will refuse the support if the documents are not compliant.

Lithium-Ion
Li-ion has established itself for camera batteries (V-mount) because of its Power/Capacity/Weight ratio.
The three main problems related to this chemistry are :
- the high risk of fire (self-combustion, fire risk in the event of an impact or short circuit, reliability of BMS) as well as the toxicity of the fumes.
- reduced service life, about 300 to 500 load cycles (usually 2 to 3 years of operation)
- pollution problems related to manufacturing and the difficulty of recycling.

For MEUs, the choice of Li-ion is questionable because of the problems mentioned above that multiply due to the amounts of lithium ion contained. For example, the 3-year lifespan is acceptable for a battery at 250 €, much less on an UME of more than 5 000 €.

Lithium-Iron-Phosphate
Iron-Phosphate batteries (LiFePo4) are much more suitable for this application : lifespan around 2,000 cycles, non-flammable and much less polluting to manufacture and recycle.
The problem of this chemistry is related to the slightly higher weight/power ratio of the battery but on an MEUs this has few consequences, due to the high weight regardless of the chemistry used.

L’Axsol Arvey Série E - E5, Unité Mobile Electrique LiFePO4 (Lithium Iron-Phosphate) 5 000 Watts / 6 144 Wh.
L’Axsol Arvey Série E - E5, Unité Mobile Electrique LiFePO4 (Lithium Iron-Phosphate) 5 000 Watts / 6 144 Wh.

Standards and accountability
One of the characteristics of our industry is the need for artisanal production : we are in a niche market and the quantities manufactured are often insufficient to interest an industrialist. This is one of the major attractions of our business but also a problem when we go on dangerous products.
In terms of batteries, many rental companies create their own solutions, often well thought out and well done but which, for lack of time and resources, do not necessarily pass all the necessary certifications.
In the event of a disaster, the problem of liability will arise, with major consequences for managers.
For products manufactured within the Community, the manufacturer is responsible.
For imported products, the distribution companies assume responsibility on behalf of the manufacturer.
For the productions that ensure their shooting, they must inquire and ask their suppliers for battery certifications.

The approach of adapting validated solutions in industry and the military field therefore offers the advantage of meeting all the standards and certifications necessary for MEUs.