Lithium batteries and nickel-cadmium batteries and nickel-metal hydride batteries than what are the advantages?

Source: 2020 - 04 - 14 18:58 hits: time compared to the common nickel cadmium battery and nickel metal hydride batteries, lithium batteries have a lot of superior properties, mainly manifested in the following respects: ( 1) Lithium battery power supply voltage is high, the general is 3. 6 V, is the nickel cadmium battery and nickel metal hydride battery voltage of about three times. For high voltage electronic devices, the number of batteries battery series can also be greatly reduced. Therefore, the compound lithium battery can easily obtain a higher voltage. ( 2) Is higher than that, the same weight of lithium battery is higher than other batteries to provide energy. Lithium battery than can usually nickel cadmium battery and 2 ~ 3 times of nimh batteries. Therefore, it is advantageous to the portable electronic equipment is small in size and light weight. ( 3) No memory effect. Nickel cadmium battery and nickel metal hydride battery memory effect, must regularly discharge, otherwise the battery will fail because of memory effects. And lithium battery has no memory effect, do not care about how much of the remaining power, can charge the battery directly. This makes the efficiency of lithium-ion batteries are fully play. ( 4) Long service life. Lithium battery using carbon anode, carbon negative won't produce in the process of charging and discharging lithium metal, make the battery to avoid the damage caused by metallic lithium short circuit. At present, the cycle life of lithium-ion batteries can reach more than 5000 times, far higher than other types of batteries. ( 5) Working environment temperature range is wide, generally between 30 ℃ ~ 0 ℃, with excellent high and low temperature discharge performance. ( 6) Low self-discharge rate. Self-discharge rate, also called charge retention, is refers to the number of battery is not placed automatic discharge. Lithium battery self-discharge rate was 2% ~ 5%, the nickel cadmium battery self-discharge rate was 25% ~ 30%, nickel metal hydride battery self-discharge rate was 30% ~ 35%. As a result, the lithium battery in the same environment to keep the longest charging time. ( 7) Lithium-ion batteries do not contain any toxic elements such as mercury, cadmium, is the real green battery. Based on the above advantages, the lithium battery has been widely used in portable electronic devices. Lithium battery, on the other hand, high energy density, so it is difficult to guarantee its safety. Specifically, in the case of overcharge, the electrolyte will be dismantled, cause the battery internal temperature and pressure. After discharge, anode material of electrolytic copper melt due to internal short circuit, raise the temperature, the external circuit electrical short circuit or discharge 3 to the first chapter, the characteristics of high resistance, increase internal battery power, temperature, may lead to the oxidation and decomposition of the electrolyte, lithium battery life. In addition, if excessive discharge lithium battery, can lead to internal battery electrolyte to produce change, but the number of times a charging circuit so will reduce, which affect the service life of lithium-ion batteries. Due to the shortcomings of lithium-ion batteries, must be increased in the application of lithium battery protection circuit. The basic function of the protection circuit shall comply with the above shortcomings, therefore we require lithium battery power protection chip to achieve the following basic functions: the overcharge protection, discharge protection, over current protection and short circuit protection. According to the above application requirements of lithium battery, in order to improve the service life of the lithium battery, ensure the safe usage of battery, lithium battery protection circuit should have the following functions: ( 1) Charging voltage exceeds battery allow maximum charge voltage, can provide the battery discharge circuit. ( 2) If a battery discharge voltage is lower than the minimum allowable values, can provide the battery charging circuit. Cut off the battery and the external circuit connection, to cut off the battery and the external circuit connection ( 3) When the battery charge and discharge current is greater than the limit value, should cut off the battery and the external circuit connection. ( 4) When the battery returned to normal, protective circuit should be able to lift its state of protection accordingly, make a battery can continue to work normally.