Batteries are defined as chemical energy supplies, capable of releasing electric current. While wet cell batteries get their power from a liquid electrolyte, dry cell batteries generate power from a slightly moist paste. Batteries can also be divided into two other classes: primary, or single-use disposables, and secondary, or rechargeables.
Dry Cell Characteristics
The more visible of the two battery types, the dry cell battery, was first made from zinc and carbon and was invented by Carl Gassner in 1887. All dry cell batteries have a metal electrode or graphite rod encompassed by an electrolyte paste, all within in a metal container. In an acidic dry cell, the electricity-generating reduction reaction typically takes place in a paste comprised of ammonium chloride (NH4Cl) and manganese dioxide (MnO2). In a longer-lasting alkaline dry cell, potassium hydroxide (KOH) or sodium hydirxide (NaOH) reacts with manganese dioxide. Other batteries might use silver oxide (Ag2O), mercury Oxide (HgO) or nickel/cadmium. Dry cells can be either primary or secondary cells.
Wet Cell Characteristics
A well cell battery generates power from an electrode and a liquid electrolyte solution. Early wet batteries consisted of solution-filled glass jars and with an electrode dropped into each one. About the size of the average toaster, modern wet cells are used in the ignition system of most cars and are comprised of lead and a solution of sulfuric acid. A sheet of insulation is typically used to separate the anode from the cathode. Wet cells can be either primary or secondary cells.
Dry Cell Advantages
Unlike wet cell batteries, dry cells can be operated in any position. Also, since dry cells are more durable, they are typically used for cell phones, flashlights and other similar handheld devices. Dry cells are typically used as primary cells, and these batteries are often used for long periods of storage because they have have a lower discharge rate than secondary batteries. Lithium ion batteries represent a type of dry cell battery that is particularly suited to use in cell phones, due to its high energy density, or its power stored versus weight. This means a small compact, durable battery can deliver a large amount of power.
Wet Cell Advantages
Wet cell batteries are typically used as secondary batteries and therefore can be recharged by another power source. This makes them ideal of use in motor vehicles. For the amount of power that they supply, and as long as they last, wet cell batteries are considered fairly affordable. If properly maintained, wet cell batteries also have a high number of charge-discharge cycles. They are also less likely than other batteries to be damaged by overcharging.