Rechargeable batteries are rechargeable batteries with limited number of charges, which are used in conjunction with chargers. When its electricity is used up, the current is applied to it. It can convert electrical energy into chemical energy. When the electricity is turned on, the battery converts chemical energy into electrical energy through chemical reaction. In this way, charging-discharging-charging-discharging, it can be recycled.
1. The advantages of rechargeable batteries are that it is economical, and environmentally friendly. It has enough electricity. It is suitable for high-power, long-term use electrical appliances, such as walkman, electric toys and so on.
2. The voltage of rechargeable batteries is lower than that of disposable batteries of the same type. AA batteries (No. 5 charging) are 1.2 volts, and 9V charging batteries are actually 8.4 volts. Now the average number of charges can be about 1000 times.
3. Its cycle life is long. It can charge and discharge more than 200 times. Some rechargeable batteries have higher load than most disposable batteries.
At present, there are only five kinds: nickel and cadmium, nickel and hydrogen, lithium ion, lead storage, iron and lithium.
1. Nickel-cadmium batteries (Ni-Cd)
Characteristic: It has memory effect and small capacity.
2. Nickel-hydrogen battery (Ni-MH)
Characteristics: It has small memory effect and large capacity. At present, the maximum capacity of domestic No. 5 battery is about 2500 mAh.
3. Lithium-ion batteries (Li-lon)
Characteristic: It has no memory effect, is very thin and has large capacity. Its weight is 30%-40% lighter than that of Ni-MH battery, and its capacity is 60% higher than that of Ni-MH battery. But it can't stand overcharging. If it is overcharged, the temperature will be too high to destroy the structure=> explosion. The electromotive force is 3.6V and 3.7V because of different electrode materials. The performance of lithium batteries is the best of all kinds of batteries. They are small in size, light in weight and large in capacity. It is widely used in digital cameras, laptops, mobile phones and other electronic products.
4. Li-polymer battery
Characteristic: The improved lithium battery has no battery liquid, but can be made into various shapes by using polymer electrolyte, which is more stable than lithium battery.
Characteristic: It is a general car battery, which is connected in series with 6 2V to 12V. Water-free batteries have a life of up to 10 years, but their volume and capacity are the largest.