Classification and analysis of rechargeable batteries

There are many types of rechargeable batteries, but they require high energy density, light weight, and large discharge current when used on model airplanes. At present, nickel-cadmium batteries, nickel-hydrogen batteries and lithium batteries are urgently used. The internal resistance of the rechargeable battery is low, so be careful not to short-circuit when using it, otherwise it may cause burns and fire. The key feature of nickel-cadmium batteries (Ni-Cd) is excellent high-current discharge performance, which meets the short-time and high-power requirements of model aircraft. An important performance index of rechargeable batteries is the discharge rate. The so-called discharge rate refers to the ratio of the maximum continuous discharge current of the battery to its capacity C. C represents the number of hours required to complete the discharge of one ampere. It is usually indicated by adding a number before the capacity C. For example, the discharge rate of a Grignard 1800mah battery is 10C, which means that its maximum continuous discharge capacity is 18A. It can be seen that the discharge rate is an important indicator of the rapid discharge performance of the battery. Due to differences in processing technology and structure, the discharge rates of batteries of different brands are often different. Domestic nickel separator batteries are generally 6C~12C, and imported batteries are usually higher, especially lithium-ion batteries for model aircraft, which can reach about 20C. The first choice of battery is to choose a battery with a high discharge rate. However, the energy density of the nickel-cell battery is small, and it has a memory effect. The waste battery has a relatively large environmental pollution and will be quickly eliminated. At present, it is only used in the occasion of extremely large current output. Nickel-metal hydride battery (NiMH) is an environmentally friendly rechargeable battery. The performance and charging method are the same as nickel-cell batteries. The nominal voltage is also 1.25v, but the power density is greater. At present, it has replaced nickel-cell batteries in many occasions. Batteries are not as good as nickel-cell batteries in terms of high-current discharge performance, generally around 7C. Nickel separator batteries and nickel-metal hydride batteries have the same series of models, and the commonly used ones are SC type, A type, AA type (No. 5), AAA type (No. 7), etc. In addition, there will be some special models of batteries, which are usually extended or shortened models derived from the standard battery model specifications. Battery cells (cells) are sometimes marked with the battery size straight, such as 18650 and 1848, which indicate single cells with a diameter of 18 mm and a length of 65 mm and 8 mm respectively. The motors and receivers in the model airplane use power sources. Their voltages are generally above 5V, and the power packs are generally above 9~12V. This requires multiple batteries in series, usually connected by spot welding with nickel sheets. Amateur production can be soldered with copper foil, but be aware that the soldering time is short and the battery is damaged. 1300-45C-3S-1 lithium ion polymer battery (Li-Poly) is currently the mainstream of rechargeable batteries. It has been widely used in handheld electronic products such as mobile phones. The monomer voltage of lithium ion polymer is as high as 3.6v, the energy density is large, the weight is light, and there is no memory effect. However, the charging and discharging requirements of lithium batteries are relatively high, and it is difficult to achieve high-current discharge, otherwise it is very easy to damage the battery. The discharge capacity of the lithium-ion polymer battery for aircraft models has reached more than 10C, and the safety of the lithium-ion polymer battery is no longer a problem, but it must be protected by a special charge and discharge protection circuit. There are many packaging forms of lithium ion polymer batteries, most of which are flat rectangular parallelepiped, and each battery has a dedicated protection circuit. When the discharge voltage is lower than the time or the discharge current is higher than the time, it will be automatically protected. Many batteries The protection circuit also has a charging protection function. 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: Detailed research status of power lithium battery pack protection