Ball bearings only on one side, and smashed "ring"?
There are supposed to be ball bearings on both sides of the hub. You need to rebuild the bearings replacing at least the non-drive side balls. 

Bicycle hubs with loose ball bearings use a ‘cup and cone’ system. The cups and cones have the bearing surfaces and the balls are sandwiched between them. The cups are in the hub, the cones are threaded into the axle. 

There are many videos on YouTube that will show you how to disassemble, repair and reassemble a cup and cone hub. RJ The Bike Guy has a good one. 

You’ll need to inspect the cup and cone bearing surfaces for wear or pitting. the axle, cones, spacers and balls can all be replaced. Balls come in a couple of different sizes. If you don’t have accurate calipers a local bike shop can help you out.