Mine also broke off. Got a male spade terminal and cut the cable entry part off.
Clean the part that you are going to solder and file the broken edge smooth. Using a fairly large soldering iron...not those small one's for electronics.."Tin" the broken part, get someone to hold the spade section with a pair of piers and then put a good run of solder on the joint.
If you have some Fluxite or similar, it will be better and easier than relying solely on the multicore flux in the solder.