Safest batteries allowed for transport by air - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: January 05, 2020, 07:53:29 pm
content: Hi,we are designing a portable tester which the client requires to be safe & allowed for transport by air. Because the equipment has to run for up to 10 hours the battery need to be up 20Ah (the size of a phone-sized battery pack). The battery pack is fixed inside the enclosure so the battery cannot be removed.Do you know which type is the safest?What types of tests and certifications are required?Do you know where I can find any docs/infos about this?Thank you

author: wraper
author_rank: Unknown
timestamp: January 05, 2020, 08:44:58 pm
content: Transport by courier or with person? If by person AFAIK you can take up to 100Wh Lithium battery. If by courier I think power limit is the same but battery must be discharged <30%, package properly marked and also particular courier should want to deal with them. Some stupid couriers simply refuse any batteries altogether.

author: reboots
author_rank: Regular Contributor
timestamp: January 05, 2020, 09:03:48 pm
content: Disclaimer: the following information relates to the USA, and might not hold any relevance for your location. I can't answer your question about tests and certification, but perhaps the regulations governing what you can transport by air would be a starting point.For transport by the client on US air carriers (as opposed to shipping), a battery contained within equipment is limited to 100Wh. You didn't mention the required battery voltage, but 100Wh / 20Ah = 5V. A 3.7V nominal Li-Ion pack would be 74 Wh; no problem. Further reading:https://www.faa.gov/hazmat/packsafe/more_info/?hazmat=7Based on British Airways restrictions, the UK may have similar limits.https://www.britishairways.com/en-gb/information/baggage-essentials/liquids-and-restrictions#For shipping lithium batteries contained in equipment, see international standard UN3481, PI967. This mandates the same 100Wh limit for the battery. (Or maximum 20Wh per cell).http://www.dhl-usa.com/content/dam/downloads/g0/express/shipping/lithium_batteries/lithium_ion_batteries_regulations.pdfI deal with custom equipment assemblies which contain a li-poly pack and are carried internationally. I have heard of incidents where customs agents asked for visual confirmation that the pack was disconnected, and in some cases, wanted to see an insulating plug installed so that the pack could not be connected accidentally. Depending on the level of integration in your product, adding this type of measure might be a good idea.My personal opinion is that cylindrical Li-Ion cells are safer for this type of application than prismatic Li-Poly packs, having better protection against mechanical shock and stress. Unfortunately they are heavier, and use space less efficiently, so they're less preferred for portable equipment.

author: ebclr
author_rank: Super Contributor
timestamp: January 06, 2020, 03:12:18 am
content: It's not easy in today's freight to have rechargeable battery transported in wholesale quantities, I have a lot of issues on the freight company door, especially in China, They really don't understand what is safe and what is dangerous and ask a lot of things and costly paperwork even for a simple mouse NI-MH battery, This is more critical for air shipping, But even on sea shipping have some issues. This depends a lot of with shipping company you are using, some don't permit nothing, others do not care and are very permissive. It's a very stressful thing if you want to play in the right way.Be ready to handle a lot of paperwork

author: ricko_uk
author_rank: Super Contributor
timestamp: January 06, 2020, 12:37:39 pm
content: Thank you all for all the inputs, much appreciated!!

author: jbb
author_rank: Super Contributor
timestamp: January 07, 2020, 12:15:36 am
content: Thought about this a bit.LiFePO4 cells may be somewhat harder to set on fire (still possible I’m sure!) and last many more charge/discharge cycles but still fall under the same rules. They are also larger and more expensive per unit energy.The per-cell energy limit can be worked around by connecting cells in series (obvious) or parallel (if paralleling, you should use all the same cells and make sure their voltages match to a few mV before connecting).Most importantly, you should have a good look at your design (preferably measure a prototype in use) to see where the power’s going. If you can reduce the power consumption, that translates into a cooler product with a smaller battery. Possible avenues for improvement:- review system operation scheme. Does everything really need to be on all the time?- look for dumb loads that don’t need to be on all the time (eg fans, unimportant indicator lights)- review power supplies for efficiency (note, linear regulators are not automatically bad and switching regulators can have terrible efficiency at light load)- if lots of power is going to microprocessors, use sleep modes- if some power hungry circuits only need to be used sometimes, install power switches to turn them off when not in use- could some power-hungry part be replaced by a different lower-power technology?

author: ricko_uk
author_rank: Super Contributor
timestamp: January 08, 2020, 02:48:30 am
content: Thank you JJB, much appreciated suggestions!!