Från Wikipedia :
Med andra ord hade han ursprungligen inte dem, och de var dekorativa (och formade som batwings innan de förenklades) efter det, förmodligen helt fram till Batman Begins , där de fick en funktion.Batman is often depicted as wearing dark-colored gloves which extend to cover most of his forearms. In the earliest Batman stories of Detective Comics, the costume featured a few curiosities before it evolved in to its more or less standard style. The first gloves were purple in color, ordinary looking, and lacked any sort of scalloped fins or other stylings, and only came to the wrists. The second Batman adventure depicted the character wearing no gloves at all. A few issues later the gloves became longer, and by 1940 the familiar fins were added (in early stories, these pieces originally resembled miniature, scalloped bat wings, but eventually became three simple triangular fins).
IngaspikariDC#27
Inga handskar i DC # 29
Batwing handskar i DC # 46