Kyocera Brigadier has an internal battery....do not attempt to open the back panel, as this will void manufacturer warranty.
link to manual: http://www.kyoceramobile.com/brigadier/Brigadier-User-Guide_en.pdf
Try charging it for at least 5 minutes then try turning it on again. Make sure that you use a different charge 'cause it may be the one causing the problem. Re-install the battery too to make sure there's no problem in it.