PPRuNe Forums - View Single Post - Design review for 787 and “Plan B” for A350 XWB triggered by Lithium ion batteries
Old 20th Feb 2013, 20:31
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RR_NDB
 
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Where is the safety valve* of the battery case? The battery case was sealed?

Hi,

grebllaw123d:

It is stated that the cell has a Sealed Structure. I suppose that it means that all gases (normally!) will be held within the structure of the cell, just like on a AA battery, so no need for a vent?
You are right! The chemistry in these cells doesn´t require venting. At least in normal conditions. but if the cell has this safety exit, why not the battery was not designed with it? Or something less "sealed" (Lyman: My take on the design of the Stainless enclosure is that the top was not "sealed").

What concerns me is:

Cells heat and we don´t see in the battery case means to provide an expansion (and inverse movement when cooling down)

The venting i mentioned (your observation is correct) is not on the meaning of traditional batteries.

On the picture "Cell construction" there is a white circular "thing" just below the plus terminal labelled "Rupture plate". I suppose that this plate will blow out, if some serious failure has occured within the battery in order to relieve excess pressure.
Better expressing: Why not battery case has not a similar mechanism. Certainly would be safer a "venting" (rupture mechanism) than an explosion of a battery inside an EEbay. Electrolytes certainly would create a serious risk for a plane with this structure.

Or maybe you are referring to another hole in the cell.
No, i was expressing erroneously. Thank you for precise observation!

Edited the title.

Last edited by Jetdriver; 20th Feb 2013 at 23:18.
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