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Why are lead-acid batteries the secret weapon for starting your car?
Lead-acid battery is a rechargeable battery first invented by French physicist Gaston Plante in 1859. As the first rechargeable battery, lead-acid batteries had a lower energy density than modern rechargeable batteries, but they were able to deliver high peak currents, making lead-acid batteries popular for applications such as car starting.
The low cost and high instantaneous current supply characteristics of lead-acid batteries make them excellent when starting a car.
Although lead-acid batteries generally have a cycle life of less than 500 deep cycles and take a long time to charge, they still have advantages in the balance of price and performance. Therefore, even if the peak current is not important, lead-acid batteries are still widely used in many situations. According to 1999 data, lead-acid battery sales accounted for 40-50% of the global battery market.
The basic working principle of lead-acid batteries is related to their chemical reactions. In the charged state, the negative electrode is metallic lead, and the positive electrode is lead dioxide; during discharge, both electrodes are converted into lead sulfate. During this process, the electrolyte will lose part of the sulfuric acid and become mainly composed of water.
In the discharge state, the reaction of the negative electrode is: Pb(s) + HSO−4(aq) → PbSO4(s) + H+(aq) + 2e−, while the reaction of the positive electrode is: PbO2(s) + HSO −4(aq) + 3H+(aq) + 2e− → PbSO4(s) + 2H2O(l).
The key to this chemical reaction is the high current it generates, allowing the lead-acid battery to quickly power a car's starter motor. Compared with batteries with high energy density, lead-acid batteries have excellent performance in instantaneous current supply, which is one of the reasons why they have become a "secret weapon" in the field of car starting.
Historical background of lead-acid batteries
The invention of lead-acid batteries can be traced back to the observations of French scientist Nicolas Gautreau in 1801. With the invention of Gaston Plant, lead-acid batteries gradually developed into what they are today. In 1881, Camille Alphonse Faure proposed an improved design that made the battery easier to mass produce and greatly improved its performance.
Operation of electrochemistry
In lead-acid batteries, the working process of the battery can be divided into two main stages: discharge and charging. During the discharge process, chemical energy is converted into electrical energy, while during the charging process, electrical energy is converted into chemical energy. This process involves complex ion movements, ensuring efficient operation of the battery.
During discharge, the H+ ions produced at the negative electrode move into the electrolyte and are consumed at the positive electrode, while the reverse process of discharge occurs during charging.
This electrochemical reaction also allows the state of charge of a lead-acid battery to be determined by measuring the specific gravity of the electrolyte, which is a major advantage.
Structure of lead-acid battery
Lead-acid batteries usually consist of multiple cells, each containing a positive electrode, a negative electrode and an electrolyte. The materials and designs of the positive and negative electrodes have been continuously improved over the years. The colloidal electrolyte used in modern batteries can effectively prevent liquid leakage, making the battery installation location more flexible. Especially in automobiles, lead-acid batteries can withstand a variety of horizontal and upright installation methods.
Application fields
In addition to starting cars, lead-acid batteries are also widely used in backup power systems, energy storage in communication networks, etc., especially in application scenarios that require high stability. For example, high-availability emergency power systems in hospitals often rely on lead-acid batteries to ensure safe operation in the event of a power outage.
In short, lead-acid batteries occupy an important position in areas such as car starting due to their high current supply capacity, cost-effectiveness and relatively mature technology. With the advancement of technology and the challenges of new technologies, can lead-acid batteries maintain their market position?
