Hi Charlie, IEC TR 62368-2 doesn't provide much guidance on clause M.4.3 other than that lithium batteries should be considered Potential Ignition Sources.
In general, a polymeric fire enclosure isn't necessarily going to contain a fire. V-1 and V-0 materials will burn through, and the standard does not require 5-VA to completely contain a flame. However, the enclosure can slow the propagation of a fire. For many smaller lithium-ion batteries, a fire enclosure will contain the fire long enough for much of the energy to be released, reducing the risk that the fire will spread to flammable materials outside of the enclosure. A user holding or wearing a device with a lithium battery will likely have time to react and separate themselves from the device should the battery fail exothermically. I can't state whether a thin film or tape would be suitable. I can only suggest a risk analysis. Best regards, Ted Eckert The opinions expressed are my own and do not necessarily reflect those of my employer or TC 108. From: Charlie Blackham <[email protected]> Sent: Sunday, October 10, 2021 8:02 AM To: [email protected] Subject: [EXTERNAL] Re: [PSES] UL 510 Flame retardant tape Rich, Ted, All The product has an outer enclosure that provides suitable mechanical strength and the battery is IEC62133 compliant charged and discharged via a suitable chip There's a product requirement for a yellow enclosure, and we can't find a suitable yellow plastic with enough fire retardancy. The issue is that Clause M.4.3 mandates a fire enclosure and it's never clear (to me anyway) whether some batteries actually have their own fire enclosure as I don't see this listed anywhere, and you might get for Conditions of Acceptability for a Recognised Component PSU. If a LiIon battery really does "cook off" I'm not sure what enclosure would actually contain it - I guess it might be as much about whether the enclosure provides more fuel, but I'm not sure as to the intent of the clause in the standard Best regards Charlie Charlie Blackham Sulis Consultants Ltd Tel: +44 (0)7946 624317 Web: https://sulisconsultants.com/<https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsulisconsultants.com%2F&data=04%7C01%7Cted.eckert%40microsoft.com%7C4596811e7f144457823a08d98bfef963%7C72f988bf86f141af91ab2d7cd011db47%7C0%7C0%7C637694750432063193%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=Hs9DP3uv4zELUqMFw3o9n1v1G8bx3IebCAW2VpQby1Y%3D&reserved=0> Registered in England and Wales, number 05466247 From: Richard Nute <[email protected]<mailto:[email protected]>> Sent: 08 October 2021 22:42 To: Charlie Blackham <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]> Subject: RE: [PSES] UL 510 Flame retardant tape Hi Charlie: Rather than guess: https://www.kaptontape.com/PDF/Kapton_Films_Datasheet.pdf<https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.kaptontape.com%2FPDF%2FKapton_Films_Datasheet.pdf&data=04%7C01%7Cted.eckert%40microsoft.com%7C4596811e7f144457823a08d98bfef963%7C72f988bf86f141af91ab2d7cd011db47%7C0%7C0%7C637694750432073186%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=s2aNcZKd39Cu4OC2mi41q4S5lys3s%2Fpztnwit8B1RTA%3D&reserved=0> https://www.dupont.com/content/dam/dupont/amer/us/en/products/ei-transformation/documents/DEC-Kapton-HN-datasheet.pdf<https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.dupont.com%2Fcontent%2Fdam%2Fdupont%2Famer%2Fus%2Fen%2Fproducts%2Fei-transformation%2Fdocuments%2FDEC-Kapton-HN-datasheet.pdf&data=04%7C01%7Cted.eckert%40microsoft.com%7C4596811e7f144457823a08d98bfef963%7C72f988bf86f141af91ab2d7cd011db47%7C0%7C0%7C637694750432073186%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=vuMMQdJ7kFIOxwXI3rp3BclV1eQYe2Pk0gtLpMdhvCU%3D&reserved=0> https://www.dupont.com/content/dam/dupont/amer/us/en/products/ei-transformation/documents/EI-10167-Kapton-General-Specifications.pdf<https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.dupont.com%2Fcontent%2Fdam%2Fdupont%2Famer%2Fus%2Fen%2Fproducts%2Fei-transformation%2Fdocuments%2FEI-10167-Kapton-General-Specifications.pdf&data=04%7C01%7Cted.eckert%40microsoft.com%7C4596811e7f144457823a08d98bfef963%7C72f988bf86f141af91ab2d7cd011db47%7C0%7C0%7C637694750432083178%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=%2FujrQWLQsG%2BYLGZ9G7yj9Saf1wTMaD6F24zvDgUftjw%3D&reserved=0> After looking at the above specs, I'm inclined to believe that Kapton tape will provide an acceptable fire enclosure (as good as any other plastic material). It is tough stuff! And relatively expensive. If you are going to test it (as suggested by Ted), I suggest a side-by-side test with the alternate fire enclosure plastic material. Note that IEC 62368-1 uses IEC 60695-11-10 for flammability rating rather than UL 94 and UL 510. There are no specific requirements for fire-enclosure tape. Stay safe, and best regards, Rich From: Charlie Blackham <[email protected]<mailto:[email protected]>> Sent: Friday, October 8, 2021 6:25 AM To: [email protected]<mailto:[email protected]> Subject: [EXTERNAL] [PSES] UL 510 Flame retardant tape All Various Kapton tapes are sold as Flame Retardant, some seem to reference UL 94 and others UL 510. The scenario is a product falling under EN 62368-1 and the secondary lithium battery needs a fire enclosure and rather than using the product enclosure, one could be made for the battery using a suitable plastic or manual application of retardant tape. Is there any correlation between UL 510 and UL94 when considering creating a Fire Enclosure for a battery as per Clause M.4.3 ? Best regards Charlie Charlie Blackham Sulis Consultants Ltd Mead House Longwater Road Eversley RG27 0NW UK Tel: +44 (0)7946 624317 Email: [email protected]<mailto:[email protected]> Web: https://sulisconsultants.com/<https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsulisconsultants.com%2F&data=04%7C01%7Cted.eckert%40microsoft.com%7C4596811e7f144457823a08d98bfef963%7C72f988bf86f141af91ab2d7cd011db47%7C0%7C0%7C637694750432083178%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=EXXsXOdWnOk%2B4L3wZYdAY%2BwiCvUySSP2Y2V%2Bxu9Af6Q%3D&reserved=0> Registered in England and Wales, number 05466247 - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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