Many laptop battery packs of that era are constructed of "cells" which were really sets of AA batteries soldered together - this may have been for cost savings or for meeting transport regulations. Many laptop batteries are still manufactured in this way (Sony, Dell).
There are several sources online for Powerbook 190/5300 remanufactured batteries, if you don't want to attempt to replace the cells yourself. Pre-tabbed NiMH cells are readily available, as are companies which will rebuild your battery pack - recycling the old cells in the process and keeping them out of the landfill.
http://www.atbatt.com/laptop-batteries/b/apple/m/powerbook-190.asp
http://www.welovemacs.com/m3254.html
http://lowendmac.com/musings/06/0908.html
http://www.interstatebatteries.com/cs_eStore/Search.aspx/Computers/Apple/POWERBOOK-190CS?dsNavigation=N~27-4294939843-4294938153
http://www.batteryrefill.com/laptops/apple/