Page 348 - Handbook of Battery Materials
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318 11 Separators
Figure 11.21 Polyethylene separator: diagonal industrial battery profile.
Figure 11.22 Polyethylene separator: sinusoidal profile.
shown the latter to yield to expansion of the negative electrode during cycling.
Capacity deterioration by overexpansion and gas trapping results; thus a narrower
rib spacing is desirable, but is limited by increased acid displacement. Interrupted
ribs or even dotted spacers (dimples) on the backweb are under discussion.
Flexible polyethylene separators have facilitated a novel cell construction: the
separator material, supplied in roll form, is wound so that it meanders around
electrodes of alternating polarity (Figure 11.23), requiring ribs in the cross-machine
direction; such profiles are available commercially [60].
Figure 11.23 Polyethylene separator: meandering separation.
