Swollen battery over time, touchpad stopped working and case cracked.

[Bklyncmt]

•  WHY IS HP NOT REPLACING DEFECTIVE BATTERIES?

My touchpad stopped responding a year or so ago. I started using a USB connected mouse. Now my case is bulged and cracking. 

HP knows which computers have defective batteries, why did they not warn us or offer to fix or replace 

[Huffer]

Hard to explain when people seem to already know the answer but a swelling battery is not "defective". It is something that happens in a small percentage of cases to lithium-ion polymer batteries. All kinds of them; cell phones, all brands of laptops, etc. HP has no way to know your battery is swelling. Dell has this to say about it and other laptop makers have posted similar statements:

Swollen Battery Information and Guidance | Dell US

Not sure how much damage has occurred to the casing of the laptop but your battery can likely still be replaced. Post back if you are interested. 

[PeteC22]

Huffer is spot-on.  Yes, HP has identified and quickly puts out alerts when there have been a batch of laptop batteries that were known to be prone to failure, over the years I've had 2 HP laptops with this concern - in both cases the battery never did fail or develop an issue.  Those they did offer a replacement on.

However, that does not mean that your laptop had a known battery issue.  Li-ON batteries are notoriously fickle.  I've had Li-ONs that performed well years past their anticipated life span and others that failed quite rapidly.  Battery swelling is not common, but it does happen.

Most laptop makers in an ever-increasing desire to minimize weight and size have made the batteries internal versus the old battery pack that attached to the back of the laptop.  Great for making a thinner/lighter laptop - not so great when an issue occurs such as what you have.  This has likely gone on for some time, as your touchpad likely was impinged upon as the battery began to swell.