According to this site's very knowledgeble msinger:
DJI covers them under warranty for 200 charge cycles. If you care for your batterieslike this, they should live a longer life.
That count increments after each battery cycle. A cycle is when the battery is charged from 0% to 100%. Since the battery is never at 0% when you charge it, it'll take at least two charges to increment that count.
Over the past few months I've been impressed with the Spark's batteries. I've got 140 charges on two of my originals and at this point their runtime has reduced by about 1-1.5 min compared to my newest battery with 40 cycles.