Nickel-metal hydride batteries and lithium batteries are widely used in the market. They are pollution-free and environmentally friendly batteries, which is an important field of new energy development. So which good is nickel-metal hydride batteries and lithium batteries?
Nickel metal hydride battery is the main choice for hybrid electric vehicle (HEV) due to its mature technology and good safety, but it is difficult to meet the demand of higher electrification degree. Nickel-metal hydride power battery is currently dominant mainly because the battery energy of existing hybrid cars is only 1 to 2kWh, which cannot be operated by pure electric or can run below 3km by pure electric. In the long run, nimH cannot be applied to PHEV and EV. Mainly because:
The specific energy and energy density of nickel metal hydride cannot meet the requirements of PHEV and EV. Raw material Ni (OH), the price is higher, manufacturing high energy battery cost will be higher; Nickel metal hydride battery technology development is basically mature, battery performance improvement and cost reduction space is very limited.
Nickel-metal hydride batteries have the same memory effect as nickel-cadmium batteries, but it is much smaller than nickel-cadmium batteries. So there's no need to discharge every charge (because improper handling can damage the battery), just fully charge and discharge once every three months to mitigate the memory effect. Ni-mh batteries range from 25 to 35%(month) and lithium batteries range from 2 to 5%(month). Nickel-metal hydride battery has a high self-discharge rate, while lithium battery has a very low discharge rate.
At present, the general nickel-metal hydride battery capacity can be up to 2900mAh (mAh - hour, the Chinese mainland good known as R mAh), after long-term use will leak out of slightly corrosive and harmful liquid (will be harmful to human body or damage the device using the battery), while lithium batteries have a chance to burn or explode when not in use. Nickel-metal hydride batteries are relatively safe.
Nickel-metal hydride battery voltage is 1.2V, lithium battery voltage is 3.7V, lithium battery has better discharge discharge performance. Nickel-metal hydride batteries have low pollution to the environment, mainly some acid and alkali waste gas, harmful mainly HCI, environmental protection measures in place, there should be no problem.
Compared with nickel-metal hydride batteries, the advantages of lithium-ion batteries are mainly reflected in:
1, high specific energy, energy density, about twice as high as nickel metal hydride battery, can greatly improve the endurance of electric vehicles · Higher power, small self-discharge, no memory effect, these characteristics can improve the convenience of electric vehicles;
2. Low cost of raw materials;
3, large space for technology improvement, large space for cost reduction.
4. Volume: Rechargeable lithium battery is widely used in many new mobile devices because it has the advantages of small volume (relative), light weight, low self-discharge rate and no memory effect compared with ordinary nickel-cadmium/nickel-hydrogen batteries. The batteries of mobile phones, laptops, PDAs and other mobile devices have been gradually replaced by lithium batteries.
The memory effect of nimH batteries is not very significant, a little bit. When it is urgent to use, it is not necessary to recharge after radiation. It is best to recharge after radiation when it is used at ordinary times.
5, power: lithium battery energy is large, small battery; The voltage of a single lithium-ion battery is three times that of a nickel-metal hydride battery; No memory effect, can be used as you like. But also can not be used to charge, so that the number of charge and discharge is too many, it will affect the life of the battery. Lithium battery is not suitable for long-term storage, a long time will permanently lose part of the capacity. It is best to store it in the refrigerator after charging it by 40%.
6, charging method: lithium battery charging requirements and nickel-cadmium/ni-MH battery is different, rechargeable lithium battery single voltage is 3.6V (some battery blocks may be called lithium battery). The lithium battery is generally charged by limiting voltage and current. If a friend wants to charge the lithium battery independently, it needs to be noted that its charging method is different from the constant-current charging method used by nickel-cadmium/nickel-metal hydride batteries, and the charger of ordinary nickel-cadmium/nickel-metal hydride batteries can not be used.
Although nickel-metal hydride battery and lithium battery are different, but they are new era energy battery, the progress of human life has played an irreplaceable role! Objective evaluation, when weight becomes a key factor affecting product performance and timely battery maintenance, lithium battery is a natural solution, and when high power, good safety, high reliability and economic and practical, nickel-metal hydride battery will be more advantageous.
In lithium, no matter all kinds of lithium batteries, all need battery protection plate, which integrates over current protection, over voltage protection, over release protection and other functions. In addition, long-term exposure to high temperature will lead to irrecoverable capacity loss of lithium-ion batteries, which should be considered in the calculation of project cost and project safety.
