Classification analysis of rechargeable batteries

There are more types of rechargeable batteries, but they require large energy density, light weight and large discharge current for aircraft models, and nickel-cadmium batteries, nickel-metal hydride batteries and Iron Phosphate Battery are currently used. The internal resistance of the rechargeable battery is low, beware of short circuit when using, otherwise it may cause burns and fire.

The key feature of nickel-cadmium battery (Ni-Cd) is excellent high current discharge performance, which meets the short time and high power requirements of model aircraft. A critical performance index of rechargeable batteries is the discharge ratio. The so-called discharge ratio refers to the ratio of the maximum continuous discharge current of the battery to its capacity C. C stands for the number of hours it takes to discharge one ampere. It is usually indicated by adding a number before the volume C. For example, the discharge rate of Grignard 1800mah battery is 10C, that is, its maximum continued discharge capacity is 18A, it can be seen that the discharge rate is a critical indicator of the rapid discharge performance of the battery. Due to the differences in processing technology and structure, the discharge rate of different brands of batteries is often different. Domestic nickel insulated batteries are generally 6C~12C, imported batteries are usually higher, especially model aircraft special power LiFePO4 Battery, often up to about 20C, the first choice of battery is to choose a battery with high discharge rate.

However, the energy density of the nickel insulation battery is small, and there is a memory effect, and the waste battery is more polluting to the environment, and it will soon be eliminated, and it is currently only used in the occasion of large current output. Nickel-metal hydride battery (NiMH) is an environmentally friendly rechargeable battery, the performance and charging method is the same as the nickel barrier battery, the nominal voltage is also 1.25v, but the power density is greater, and the nickel barrier battery has been replaced in quite a number of occasions, but in terms of high current discharge performance is not as good as the nickel barrier battery, generally about 7C.

Nickel-insulated batteries and nickel-metal hydride batteries have the same model series, commonly used are SC type, A type, AA type (No. 5), AAA type (No. 7) and so on. In addition, there are some special models of batteries, which are usually extended or shortened models derived from the standard battery model specifications. Battery cells (battery cells) are sometimes marked directly by the size of the battery, e.g. 18650, 1848, they are marked with a diameter of 18 mm, the length of 65 mm and 8 mm respectively. The motor and receiver in the model plane should use the power supply, their voltage is generally above 5V, and the power group is generally above 9~12V, which requires several batteries in series, and is generally connected by nickel spot welding. Amateurs can use copper-tin welding, but be aware of the short welding time and the risk of battery damage.

Lithium-ion polymer (Li-Poly) batteries are currently the most common type of rechargeable battery. It is widely used in mobile phones and other portable electronic products. Lithium-ion polymer monomer voltage up to 3.6V, high energy density, light weight, no memory effect. However, the charging and discharging requirements of lithium-ion batteries are relatively high, and it is difficult to achieve large current discharge, otherwise it is very easy to damage the battery. The discharge capacity of the special lithium-ion polymer battery has reached more than 10C, and the safety of the lithium-ion polymer battery is no longer a problem, but a special charge and discharge protection circuit is needed to protect it. Lithium-ion polymer battery packaging forms are very many, most of them are flat cuboid, and with a special protection circuit for each battery, when the discharge voltage is lower than a time or discharge current is higher than a time will automatically protect, many battery protection circuits also have charging protection function.