A (somewhat buggy) script to export all albums from Photos.app to a directory. Based on the script written by Nic Fletcher (see https://discussions.apple.com/message/28098849#28098849)

Export Photos.app Albums

-- A (somewhat buggy) script to export all albums from Photos.app to a directory
-- Based on the script written by Nic Fletcher (see https://discussions.apple.com/message/28098849#28098849)

set srcParent to "iPhoto Events" -- Folder that album is in
set exportBase to "some:path:"
tell application "Photos"
	set albList to name of every container of container srcParent
end tell
repeat with albSource in albList
	set folderExists to false
	tell application "Finder"
		if exists folder (albSource) of container exportBase then
			set folderExists to true
		else
			make new folder at exportBase with properties {name:albSource}
		end if
	end tell
	if not folderExists then
		tell application "Photos"
			set notExist to false
			if srcParent = "" then
				if exists container albSource then
					set srcContainer to container albSource
				else
					set notExist to true
				end if
			else
				if exists container albSource of container srcParent then
					set srcContainer to container albSource of container srcParent
				else
					set notExist to true
				end if
			end if
			set exportPath to exportBase & albSource as alias
			set myList to every media item in srcContainer
			
			export myList to exportPath
			
		end tell
	end if
end repeat