Chemical Battery Changes Our Life
A chemical battery is a device that converts chemical energy directly into electrical energy. It is widely used in people’s daily life. Now we must have a good understanding of the working theory types and application of chemical batteries.
The working theory of chemical battery
In a chemical battery, the direct conversion of chemical energy into electrical energy is the result of spontaneous chemical reactions such as oxidation and reduction within the cell, which take place at the two electrodes respectively. The negative active substance consists of a reducing agent with a negative potential and is stable in the electrolyte, such as zinc, cadmium, lead, and other active metals and hydrogen or hydrocarbons.
The positive active substance consists of oxidizing agents with a positive potential and stability in the electrolyte, such as manganese dioxide, lead dioxide, nickel oxide, and other metal oxides, oxygen or air, halogens, and their salts, oxygenated acids and their salts, etc. Electrolytes are materials with good ionic conductivity, such as aqueous solutions of acids, bases, salts, organic or inorganic non-aqueous solutions, molten salts, or solid electrolytes.
When the external circuit is closed, a current flows through the external circuit due to the potential difference between the two electrodes. At the same time, inside the battery, since there are no free electrons in the electrolyte, the transfer of charge must be accompanied by oxidation or reduction reactions at the interface between the active material at both electrodes and the electrolyte, as well as the migration of reactants and reaction products.
Types of chemical battery
Lead-acid battery
The lead-acid battery (VRLA) is a battery whose electrodes are mainly made of lead and its oxides and whose electrolyte is a sulphuric acid solution. In the discharged state, the main component of the positive electrode is lead dioxide and the negative electrode is lead; in the charged state, the main component of both the positive and negative electrodes is lead sulfate.
Li-ion battery cell battery
The lithium-ion battery is a secondary battery (rechargeable battery) that works mainly by moving lithium ions between the positive and negative electrodes. During charging and discharging, Li+ is embedded and de-embedded back and forth between the two electrodes: when charging, Li+ is de-embedded from the positive electrode and embedded in the negative electrode via the electrolyte, which is in a lithium-rich state; when discharging, the opposite is true.
Ni-MH batteries
Ni-MH batteries are a good performing type of battery. Ni-MH batteries are divided into high voltage Ni-MH batteries and low voltage Nickel-metal hydride batteries. The positive active substance of the Nickel-metal hydride battery is Ni(OH)2 (called NiO electrode), the negative active substance is metal hydride, also called hydrogen storage alloy (electrode called hydrogen storage electrode) and the electrolyte is 6 mol/L potassium hydroxide solution. Nickel-hydrogen batteries are increasingly being noticed as an important direction for hydrogen energy applications.
Application of chemical battery
According to the use can be divided into five sub-categories:
1, small chemical battery: small batteries with aqueous electrolytes or organic electrolytes and solid electrolytes are often used as a power source for microelectronic products and other small devices.
2、Chemical battery for portable equipment: Of all the batteries, the most familiar and inexpensive battery is probably the sealed “dry cell”, which is widely used in portable lamps, electric toys, radios, etc.
3、Lead-acid chemical battery: Every year, about 250 million SLI batteries are manufactured for internal combustion engine vehicles, consuming about one-third of the world’s lead production. Sintered lead-acid batteries are used in aircraft, helicopters, tanks, and special vehicles for onboard power, which has good low temperature performance, high discharge rate, and other important characteristics.
4, Vehicle-driven chemical battery: the widespread use of batteries to drive vehicles have many advantages: no noise, no pollution, saving fuel, and because the electric vehicle battery can be charged at night so that the main power generation system works more efficiently.