Do I need a new car battery?

I was driving home from work last night in my 01 Ford Tauras. I was maybe 5 minutes from home when my headlights went full and were flashing. My blinkers were full and were faster than normal. When I came to a stop the car had almost died when I accelerated. My question is that is there something severely wrong with my car or do I just need a new battery?

Dying batteries don't result in lights getting brighter.

Your battery is not dying, you have another problem. I have no idea what it could be.

Could be any number of things - I have never heard of those symptoms before

Maybe. This could actually be an alternator problem.

A dead battery may be the result but not the cause of the problem, sounds like a power surge to me. It needs looking at by a qualified electrician. Either an alternator over charging or wrong fuses fitted or both.

Somehow, the "best answer" was already chosen, but check to make certain the positive terminal is clean and tight on the battery. Check the wires to the alternator and make sure all are plugged in and tight. With no battery voltage to the alternator's electromagnet, it will create a sort of run away voltage of its own and make higher and higher voltage from the alternator because it can't control this without battery voltage. Probably the best thing to do is have a professional look it over, but if you have at least the experience enough raising the hood to know loose vs tight, take a look first.

Sounds like an alternator or voltage regulator fault. This can drain the battery in a very short time. Get it looked at by an auto electrician. Once the battery is recharged, get it tested too just in case it is near the end of its life. Being fully discharged can damage a car battery too.