What is the reason for the odd voltage in the battery pack?

The reason for the odd voltage appearing from the battery pack The battery is an electrochemical device, when metals with different properties are put into the electrolyte, it will appear voltage. The open circuit voltage (OCV) that occurs in an electrochemical reaction varies with the metal and electrolyte used. Apply charging or discharging to place the battery in closed circuit voltage (CCV) conditions. Charging increases the voltage, discharging decreases the voltage (just like the rubber band effect), and the voltage characteristics under load and charging are determined by the current and the internal resistance of the battery. Low resistance has low fluctuations during load or charging; high resistance causes excessive voltage fluctuations. When charging and discharging, the full voltage is stable for up to 24 hours, and the temperature is also useful. The low temperature reduces the voltage, but the heat increases. Battery manufacturers also rate batteries by specifying rated voltages. With a few exceptions, these voltages follow agreed conventions. This is the rated voltage of the most commonly used battery. The nominal voltage of lead-acid batteries for lead-acid batteries is 2V/cell, but when measuring the open circuit voltage, the OCV of the charged and dormant batteries should be 2.1v/cell. Keeping lead acid below 2.1v/battery will cause the accumulation of sulfuric acid. The lead-acid value is about 2.25v/battery during floating charge, and the lead-acid value is higher during normal charge. In consumer applications of nickel-based batteries, the rated voltage of nickel-cadmium batteries and nickel-hydrogen batteries is 1.20V/cell. Industrial, aerospace and military batteries continue to use the original 1.25V. There is no difference between 1.20v and 1.25v batteries; the label is just a preference. The nominal voltage of lithium ion of lithium battery is 3.60V/cell. Some battery manufacturers label their lithium batteries as 3.70V/cell or higher. This provides a marketing advantage, because higher voltage adds watt hours on paper (voltage times current equals watts). The 3.70v/battery rating also appears at 11.1v and 14.8v when three and four batteries are connected in series instead of the more familiar 10.80v and 14.40v. Regarding most lithium battery systems, equipment manufacturers insist on a battery rated voltage of 3.6v. How does the high voltage change? The nominal voltage is a function of the anode and cathode materials and impedance. The voltage calculation includes measuring the midpoint from 4.20v battery full to 3.0v battery cut off 0.5c load. The midpoint of the lithium cobalt alloy is about 3.60V. The same scan is performed on the lithium manganese material with low internal resistance, and the average voltage is about 3.70V. Note that the higher voltage is usually arbitrary and will not affect the operation of the portable device or the setting of the charger. But there are exceptions. Some lithium batteries with LCO structure have surface coatings and electrolyte additives, which can increase the nominal voltage of the battery and allow a higher charging voltage. In order to obtain the maximum capacity, the charge cut-off voltage of these batteries must be set accordingly. The figure below shows a typical voltage setting. Battery diagram of the voltage of a cobalt-based lithium battery. The setting of the charging terminal voltage must be correct to achieve the capacity gain. Lithium batteries with high charging voltage have a shorter cycle life than traditional lithium batteries, and because they are important for consumer products, their lifespan can be coordinated with obsolescence, thereby reducing the battery life. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: Which power lithium-ion battery is the best?