铅酸蓄电池的知识（Knowledge of lead-acid batteries）Battery knowledge
Electromotive force and open circuit voltage of lead acid battery
EMF definition
扬州凤凰岛
When the battery is open, the difference between the positive electrode balance potential and the negative electrode balance potential is determined by the reaction in the battery, irrespective of the shape and size of the cell.离别吉他谱
Electromotive force is one of the measurements of the energy output of a battery theoretically. If the other conditions are the same, the higher the electromotive force, the more energy the battery can theoretically output, and the higher the practical value.
EMF generation
The electromotive force is also equal to the difference of the equilibrium potential of the two electrodes that make up the battery, that is, E=, Phi e, + Phi e, and phi e is the equilibrium electrode potential.
The generation of the electrode potential is related to the establishment of the double layer.
A metal electrode is inrted into a solution containing the metal ion, becau the ion in the metal is different from the
chemical potential in the solution, so that the metal ion is transferred between the electrode and the solution. Under static electricity, this transfer rapidly reaches dynamic equilibrium.
Open circuit voltage
The terminal voltage of the battery in open circuit is the open circuit voltage, which is also the difference of the electrode potential between the two poles, but not the equilibrium potential, but the difference between the stable potential or the mixed potential.
In theory, the open circuit voltage of a battery is not equal to electromotive force, but it may be near to the numerical value.
The electromotive force of the electromotive force of a lead-acid battery is a function of the concentration of sulfuric acid. The open circuit voltage is also a function of sulfuric acid concentration.
正能量签名The relation between the open circuit voltage of the cell and the electrolyte density can be calculated
in the lower form:
Open circuit voltage =d+0.85
In D, at the temperature of the battery electrolyte, the density of the electrolyte (g/cm3)
大蒜怎么吃Establishment of stable potential
免费耽美小说Dynamic equilibrium between electrode metal ions and metal ions in solution
Me - 2e Me2+
It is only an ideal condition, such as the establishment of the above equilibrium electrode potential. In fact, in aqueous electrolyte solution on the electrode, not only there is a pair of metal oxide and metal ion reduction reaction, there is also the oxidation of hydrogen ions and hydrogen reduction, the other on the electrochemical oxidation and reduction reaction of oxygen or water, i.e.
2H+ +2e H2
Relationship between open circuit voltage and battery charge state
According to the total reaction in the lead-acid battery, it is known that when the discharge is ud, the consumption of sulfuric acid is also incread with the consumption of two lead oxide and lead, that is, with the reduction of the discharge sulfuric acid, the water concentration increas, and the acid concentration decreas. The battery open circuit voltage and the concentration of acid is a function, so the battery from the fully charged state to completely discharge state, the acid concentration changes gradually, gradually change the open circuit voltage, so voltage can be estimated by the battery state of charge of battery.
Charge discharge characteristics
Usually, constant current charge and discharge of the battery, is the terminal voltage, voltage and electrolyte of cadmium to express cell curve of density and electrolyte temperature changes over time, put some curves such as the battery, called characteristic curve, to reprent the various characteristics of the battery. Generally, there is a slight difference between the battery and the plate type.汽车仪表盘指示灯图解
During charging and discharging, the change of the terminal voltage of the battery can be indicated as follows:
Charging time: U=E+ + + delta phi delta phi -+IR
Discharge: U=E delta phi delta phi + - IR
In U, the terminal voltage (V) of the battery when charging and discharging
Delta phi + - positive electrode overpotential;
Delta phi - negative electrode overpotential;
I charge discharge current (A);
R - internal resistance of the battery (omega)
At the beginning of the charge, first incread sharply at OA voltage, then along the ABC line voltage ris slowly, continue for a long time, after reaching the C point voltage ris
rapidly, negative hydrogen gas, the cathode oxygen precipitation, water decomposition, the D voltage is about 2.6V. When discharge, the starting voltage drops rapidly, and the voltage drops slowly after E.有趣的一天日记
Change of voltage in discharge物联网的就业前景
Initially, the concentration of sulfuric acid in the micropores of the active substance is equal to m of the sulfuric acid concentration of the main body outside the plate m0. The terminal voltage (open circuit voltage) of the battery corresponds to the concentration of this sulfuric acid. However, the discharge of a surface active substance, sulfuric acid is consumed, the concentration decread immediately, and sulfate by bulk solution to the surface of the diffusion process is slow, consumption can not be timely compensation of sulfuric acid, sulfuric acid concentration of the surface active substances continue to decline, and determines the electrode potential is numerical concentration of sulfuric acid at the surface of the active material. As a result the cell voltage decread rapidly (OE curve).
2 、 change of voltage in charging
At the beginning of the charging process, as the lead sulfate is converted to two lead oxide and lead, the corresponding sulfuric acid is generated, so that the concentration of sulfuric acid on the surface of the active substance increas rapidly, so that the terminal voltage of the battery ris sharply along the OA. When the A point is reached, the terminal voltage increas slowly (ABC part) becau the diffusion
