Batteries are devices that convert chemical, light, thermal and nuclear energy directly into electrical energy. Such as chemical batteries, solar cells, temperature difference batteries, nuclear batteries and so on.

Chemical research battery at work, the battery by the positive material through the external circuit flow to the negative electrode, while in the electrolyte, positive and negative ions are migrated to the two poles, the current flows from the negative electrode to the positive electrode, which is called the discharge of the battery. When discharging, there is a chemical reaction on both electrodes of the battery, and the discharging process continues until the circuit is broken or a chemically reactive substance is depleted.lithium ion battery assembly

An important performance parameter of a battery is its voltage, which is equal to the work done by the non-static electric force (chemical force) in the battery when a unit of positive charge is moved from negative to positive through the battery. The electric potential depends on the chemistry of the electrode material, not the size of the cell. After a battery is discharged, due to a chemical reaction at the electrodes, a non-conducting gas, such as oxygen, is produced to cover the electrode surface, and the voltage then decreases, which is known as the polarization of the battery, and which can be eliminated by means of depolarizers and other methods.battery cell machine

Another performance parameter of the battery is its internal resistance. The larger the electrode area of the battery, the lower the internal resistance. The energy storage of a battery is limited. The total amount of charge that a battery can output is called its capacity, which is usually measured in ampere-hours, and this is also a performance parameter of the battery. The capacity of a battery is related to the amount of electrode material, i.e. to the volume of the electrodes.prismatic cell assembly

Practical chemical battery technology can be divided into two areas of basic data types: primary cells and accumulators.

Primary batteries generate current during manufacture, but are discarded after discharge. Storage batteries, also known as secondary batteries, must be charged before use, and can be discharged for use after charging, or recharged for use after discharging. When a battery is charged, electrical energy is converted to chemical energy; when discharged, chemical energy is converted to electrical energy.

Wet battery history, the invention of the Dannier battery in 1836 and the invention of the Le Clanchet battery in about 1865, are wet batteries. In the Dannier battery, the negative electrode is immersed in zinc sulfate solution in the zinc pole, the positive electrode is immersed in copper sulfate solution in the copper pole, the two solutions are held in the same container, the middle of the porous ceramic cups apart, so that the two solutions are not easy to seepage mixing and the ions can be free to pass through the zinc electrode, zinc atoms become zinc ions into the solution, so that zinc electrode is negatively charged; in the copper electrode, the copper ions in the solution is deposited to the copper electrode, so that the copper electrode is positively charged. Positively charged.

People used this primary cell with electrolyte in early times, but today a large number of dry cells are used, with the electrolyte absorbed in a paste. It is a modification of the Leclerche battery.

One of the commonly used dry cells is the zinc carbon dry cell. The negative electrode is a cylinder made of zinc with ammonium chloride as the electrolyte, a small amount of zinc chloride, inert filler and water as the paste electrolyte, and the positive electrode is a carbon rod surrounded by a paste electrolyte doped with manganese dioxide. The electrode reaction is that the zinc atoms at the negative pole become zinc ions (Zn++), releasing electrons, and the ammonium ions (NH4+) at the positive pole gain electrons and become ammonia and hydrogen. The hydrogen is driven away by manganese dioxide, eliminating polarization.

There are many types of batteries, and the common feature is that we can go through many charging and discharging cycles and study the use of them over and over again.

Lead-acid batteries are the most commonly used, with plates made of lead alloy gates and an electrolyte of dilute sulfuric acid. Both plates are covered with lead sulfate. However, after charging, the lead sulfate on the positive pole becomes lead dioxide, and the lead sulfate on the negative pole becomes lead metal. When discharge occurs, the chemical reaction takes place in the opposite direction.

Iron-nickel batteries are also called Edison batteries. Unlike the lead battery, which is an acidic battery, the electrolyte of the iron-nickel battery is an alkaline solution of potassium hydroxide. Its positive pole is nickel oxide and its negative pole is iron. Its advantages are lightweight, long life, easy maintenance, the disadvantage is that the efficiency is not high.

Nickel-cadmium batteries have a nickel(II) hydroxide positive electrode and a cadmium negative electrode. The electrolyte is a potassium hydroxide solution. The chemical reaction between charging and discharging is the battery has the advantages of lightweight, shock resistance and long life. It is usually used in small electronic devices.

A silver-zinc battery has silver oxide as the positive electrode, zinc as the negative electrode, and the electrolyte is a potassium hydroxide solution. The chemical reaction of charging and discharging is. The silver-zinc battery has a high specific energy, can be discharged with high current and is shock resistant. It is used as a power source for space navigation, artificial satellites, rockets, etc. Its disadvantages are high price and short service life.

Fuel Cell A device that converts the chemical energy continuously released during the combustion of fuel into electrical energy by direct influence. It differs from a storage battery in that it can be continuously replenished with fuel and oxidizer from the outside to each of the two electrode material areas without recharging itself. The fuel car battery consists of a four-part enterprise of fuel (e.g., hydrogen, methane, etc.), oxidizer (e.g., oxygen, air, etc.), electrodes, and electrolyte. Its electrodes have important catalytic technical properties between them and are of porous network structure to ensure a risky large active area. When working, the fuel is passed into the negative electrode and the oxidizer is passed into the positive electrode, and each of them is catalyzed by the electrodes to study the electrochemical reaction to obtain more electric energy.

Fuel cells convert the energy released from the combustion reaction directly into electrical energy, so they have a high energy efficiency, about twice the efficiency of a heat engine. In addition, it has the following advantages: lightweight equipment, no noise, less pollution, continuous operation, and power output per unit weight. Therefore, it is used in cosmic navigation and shows a broad application prospect in various fields such as military and civil.

Solar cell is a device that converts the energy of sunlight into electrical energy. When the sunlight shines, the terminals generate voltage and produce electric current. The solar cells used in satellites and spacecraft are made of semiconductors (often called silicon photovoltaic cells). When sunlight strikes the surface of the solar cell, it creates a potential difference between the two sides of the semiconductor's PN junction.

Temperature difference battery When two metals are connected into a closed circuit and kept at different temperatures at the two joints, an electric potential, or temperature difference electromotive force, is generated, which is called the Seebeck effect, and this device is called a temperature difference electric couple or thermocouple. Metal thermocouple temperature difference electric potential generated by the smaller, commonly used to measure the temperature difference. However, when the temperature difference electric couplings are connected in series to form a temperature difference electric pile, it can also be used as a power source of small power, which is called a temperature difference battery. Temperature difference battery made of semiconductor materials, temperature difference electric effect is stronger.

Nuclear batteries are devices that convert nuclear energy directly into electrical energy (current nuclear power generation devices utilize nuclear fission energy to heat steam to drive generators to generate electricity, but cannot convert nuclear energy released during nuclear fission directly into electrical energy). A typical nuclear battery consists of a radioactive source (e.g., strontium-90) that radiates beta rays (a high-speed stream of electrons), a collector that collects these electrons, and an insulator through which the electrons pass from the radioactive source to the collector. One end of the radioactive source becomes positive due to loss of negative charge and one end of the collector becomes negative due to negative charge. A potential difference is formed between the electrodes at the ends of the radioactive source and the collector. This type of nuclear battery produces a high voltage but a small current. It can be used for a long time on artificial satellites and exploration spacecraft.