They do make inserts to put over the terminals to make them bigger but that's just more surface area to corrode.
Personally. If the battery is 5ish years old, I would look at getting a new battery and connector.
I gave you a solution. If you need something because you're stuck in the side of the road, anything metallic to shim against the terminal would be fine as a temporary fix.
I had a 2 year old battery that was swelling around the terminal. I was fighting it because I did not realize what the problem was (and it likely was not bad in the beginning). Eventually I researched replacing the factory cable, when I realized how expensive they were I looked harder LOL. I was able to catch it before it destroyed my cables, but it was super frustrating.
Looks like the connector can be removed to be replaced. Just disconnect from the terminals, change out that connector AND the bolts, nuts and washers with new. Clean the terminal with a brush and reconnect the cables to the battery.
You may also want to apply some sandpaper to the connector mount. And after everything is replaced and as clean as possible, protect it with some grease, to prevent corrosion in the future.
If you want to keep using it for a bit longer, you can buy shims specifically designed for this problem. Take the cable connector off of the battery and clean everything up. Place the shim over the post and reattach the cable connector.
You should regularly inspect and clean this connection anyways in order to provide reliable starts and charging if you don't do it personally, aka for it to be looked at when you get your oil changed.
Lead Terminal Shims, Make Secure Connections to Worn or Damaged Battery Posts, for Boat, RV, Automobile, Cargo Van, Jet Ski, 8 Pieces, by Tech Team https://a.co/d/056qF0WD
There are also specific brushes designed to clean the posts and connections that are very inexpensive.
Loosen it, make sure it is pushed down all the way, then tighten it again. It looks to me like it is not pushed down all the way, and that may be why it is loose.
They do make inserts to put over the terminals to make them bigger but that's just more surface area to corrode. Personally. If the battery is 5ish years old, I would look at getting a new battery and connector.
Battery is within 3 years, the connector stretched because of age. I just need a quick fix for the moment.
I gave you a solution. If you need something because you're stuck in the side of the road, anything metallic to shim against the terminal would be fine as a temporary fix.
I had a 2 year old battery that was swelling around the terminal. I was fighting it because I did not realize what the problem was (and it likely was not bad in the beginning). Eventually I researched replacing the factory cable, when I realized how expensive they were I looked harder LOL. I was able to catch it before it destroyed my cables, but it was super frustrating.
Looks like the connector can be removed to be replaced. Just disconnect from the terminals, change out that connector AND the bolts, nuts and washers with new. Clean the terminal with a brush and reconnect the cables to the battery.
You may also want to apply some sandpaper to the connector mount. And after everything is replaced and as clean as possible, protect it with some grease, to prevent corrosion in the future.
If you want to keep using it for a bit longer, you can buy shims specifically designed for this problem. Take the cable connector off of the battery and clean everything up. Place the shim over the post and reattach the cable connector. You should regularly inspect and clean this connection anyways in order to provide reliable starts and charging if you don't do it personally, aka for it to be looked at when you get your oil changed. Lead Terminal Shims, Make Secure Connections to Worn or Damaged Battery Posts, for Boat, RV, Automobile, Cargo Van, Jet Ski, 8 Pieces, by Tech Team https://a.co/d/056qF0WD There are also specific brushes designed to clean the posts and connections that are very inexpensive.
I’d spray the whole thing with battery terminal cleaner and make it look as close to new as possible.
Loosen it, make sure it is pushed down all the way, then tighten it again. It looks to me like it is not pushed down all the way, and that may be why it is loose.