Hi Graham,

Without wanting to interrogate the author...

The PAS document requires all indoor locations which contain storage batteries to be ventilated to outdoors (6.5.4) and refers to BS EN IEC 62485 for further information. This does not account for various battery compositions - particularly lithium iron phosphate. There is no direct reference to a baseline ventilation rate (62485 has a calc but it's based on older battery chemestry).

Presumably we can take a sensible approach here and follow battery manufacturer's guidance/recommendations with regard to the provision and rate of ventilation?

Regards,

Peter

And if you're aiming for PassivHaus (or even generally good thermal performance), you need air tightness, so the last thing you want is uncontrolled holes in the walls.

Caravans etc have had this problem for while (most incorporate "leisure batteries") - solutions vary from a compartment only accessible from outside to a interior box with a small plastic tube to outdoors (I've no idea how effective that might be in practice). Usually lead acid, so Hydrogen is reasonably likely.

   - Andy.

An alternative may be  to have an explosion release membrane to the outside of the house, rather like the 'tear here' deliberately weakened walls and roof designs one sees on larger substation buildings and ammunition dumps and so forth. ;-)

Joking aside,one has to be clear as to the purpose of the ventilation,  the removal of heat can safely be into the house, but the removal of Hydrogen or worse a hydrogen oxygen mix rapidly becomes a serious matter requiring dilution to outside.

Equally for a well functioning lithium battery there is no gas production that vents most of the time, and if it ever it does, you may well have another problem as well namely a serious fire...

This (US) video compares shooting a rifle slug at a primary cell, a modest Lithium Ion battery (2590 prismatic size) and a zinc air cell. https://www.youtube.com/watch?v=PO8Nu3F8mkA

The 2590s are used a lot in the manpack radios, which is sobering,

Mike

An alternative may be  to have an explosion release membrane to the outside of the house, rather like the 'tear here' deliberately weakened walls and roof designs one sees on larger substation buildings and ammunition dumps and so forth. ;-)

Joking aside,one has to be clear as to the purpose of the ventilation,  the removal of heat can safely be into the house, but the removal of Hydrogen or worse a hydrogen oxygen mix rapidly becomes a serious matter requiring dilution to outside.

Equally for a well functioning lithium battery there is no gas production that vents most of the time, and if it ever it does, you may well have another problem as well namely a serious fire...

This (US) video compares shooting a rifle slug at a primary cell, a modest Lithium Ion battery (2590 prismatic size) and a zinc air cell. https://www.youtube.com/watch?v=PO8Nu3F8mkA

The 2590s are used a lot in the manpack radios, which is sobering,

Mike