Is a car battery a wet cell or dry cell?

An old battery has acid inside. Even older batteries use to have it where you put water in it to keep it charged or mantaned.
So I would have to say a car battey is a wet cell and a AA or D battery is a dry cel.
The NASCARS cars have dry cell bateries now.

Car batteries are almost always lead-acid batteries. They are made up of plates of lead and separate plates of lead dioxide, which are submerged into a solution of one third sulfuric acid and two thirds water. This is considered a wet battery because of a liquid electrolyte solution.

A car battery is a wet cell. Modern batteries (the so called maintenance-free batteries) are sealed units that have a gel inside instead of distilled water (low maintenance batteries) .

Your AA, AAA batteries are dry cells in that no liquid is involved in making them work. Good thing too as it would create a big mess!

Wet Cell.

A car battery is a wet cell battery, normally lead acid batteries. Wet cell batteries are sometimes called flooded cell batteries.

Car batteries are a type of wet cell battery. The cells inside will corrode if you don't keep the resevoir topped off with water.

Car battery are avilable in different quality. you can get wet cell which contains acid and which has got short life time then dry cell. .The most commonplace application of wet cell batteries are car batteries. Car batteries typically consist of several cells, each of which contain lead, lead oxide, and sulfuric acid as the conducting medium. The cells, linked together in a series, produce more current than a single cell alone.

A car battery can now be both a wet and dry cell battery. It all depends on which car battery you have now or want to buy. Now the batteries that are called wet cell have acid and water in them. You can buy these a Walmart. Some are yellow with a back top and some are all blaclk with red writing. Now theres also Dry cell car batteries for todays power needs. Like for example the Odyssey battery. It can operate high power stereos systems like I've got in my truck now and may in yours. This  ODYSSEY battery can be mounted inside the passengers compartment. It will never leak, gas, or corrode. It features a rugged construction and a non spillable, dry cell design and can be mounted in almost any position.
These batteries has more cranking power, more reserve capacity, and a longer design life then a Optima battery or the old everlast batteries. The PC2150 battery which I use has 2,150 amps of cranking power and 205 minutes of run time using a 25amp load. The one in my truck now measures 13" long, 10.59" wide, and 9.41" tall. I don't have to ever worry about any acid comming out of it like you see on the older batteries. So the answer to this question is that a car battery can be both a wet or a dry cell battery. In my research I found that there are more dry cell batteries in high performance cars than there is wet cell batteries. The wet cell car battery is cheaper to make. The down side is that it wront last long. Now a dry cell car battery will last three times longer then your wet cell battery and also have more power to crank your engine in the harshes conditions. So again the answer for the question asked will depend on what type of battery you are talking about. Which comes down to two answers, wet and dry cell. Like I said in the fist answer that Nascar race cars are now using dry cell batteries. They cost more then a wet cell batteries or kown as a lead acid batteries and they last longer then them too. So if you did your homework you would find that there are wet and dry cell car batteries out there.