With GNU grep, you can use -a option to make it treats binary files as text files:
grep -alir stringali -- string file
If your grep version does not support -a, you can use ack instead. With ack 1.x, you need to include -a option, with ack 2.x, you don't, since when searching include non-text file by default (only ignored non-text file when you did not specify any files).