Energy density

Gravimetric energy density uses the mass of a stated object as its denominator. Active material, coating, electrode, cell, or a product including structural parts will produce different results, so a record should list the weighed object, whether enclosure and attachments are included, and whether mass is measured or taken from a design bill.

Volumetric energy density uses an outer or controlled geometric volume of a stated object as its denominator. Material, cell, pack, or system conditions occupy different space, so a report needs to state whether it uses sample, envelope, or installed volume rather than placing incomparable spatial bases in one column.

Material, cell, pack, or system values serve different design questions. A comparison should show object, mass or volume composition, temperature, test state, and life state together; if these are absent, a number is only a lead for further supporting information and not a performance ranking.