Up to now, these two historical periods have been divided into different stages: primary batteries include carbon electricity and alkali electricity, and secondary batteries include lead-acid batteries, nickel cadmium batteries, nickel hydrogen batteries and lithium-ion batteries. Among them, lead-acid battery is a unique system, and nickel cadmium / nickel hydrogen / lithium-ion battery has technical inheritance and time succession.
Lithium ion battery is a kind of lithium battery. Lithium battery also includes lithium primary battery (lithium metal battery). Due to the wide application of lithium ion battery, people are used to using lithium battery to refer to lithium ion battery in daily discourse system. Understanding the difference between Ni MH battery and lithium battery is conducive to understanding the current and future development direction of battery technology, It is helpful to understand the current situation of the world battery industry, which is more representative than comparing the difference between lead-acid battery and lithium battery.
The emergence of lithium battery as a battery concept is not later than nickel cadmium battery, but its application is late because of the active chemical properties of lithium, which has potential safety hazards in production, use and transportation. Relying on scientific and technological progress to gradually alleviate the above pressure, lithium battery has become the mainstream of contemporary battery technology.
In practice, lithium batteries are actually developed by gradually gaining the advantages over Ni MH batteries. To sum up, the overall advantage is convenience and durability.
Let's look at the comparison between lithium battery and nickel metal hydride battery:
1. High energy density: the volume of Ni MH battery is between Ni Cd battery and lithium battery, which shows the transitional product nature of Ni MH battery. Due to different energy density, that is, the energy that can be stored in the same volume, lithium battery is three times that of Ni MH battery.
2. Self discharge: self discharge refers to the amount of power lost by the battery when it is not in use. The self discharge of Ni MH battery and lithium battery is not large, but the self discharge of Ni MH battery is common. Excessive self discharge will shorten the service time of the battery and terminate the service life in advance. Therefore, about a decade ago, low self discharge Ni MH battery was a highlight of Ni MH battery promotion, while the self discharge of lithium battery was negligible, which is the natural difference in chemical properties caused by the raw materials used by the two.
3. No memory effect: Ni MH battery has obvious memory effect. People's memory is to leave an impression in the brain, as is the case with Ni MH batteries. If the discharge is incomplete or the charging is not satisfied, the battery will only remember the incomplete and dissatisfied state over time, and the performance in application is capacity attenuation. Lithium batteries do not have this feature. Therefore, the Ni MH battery should be thoroughly discharged once every period of time to clear the left memory, which is similar to brainwashing people. Lithium battery can be charged and used at any time. Therefore, lithium battery is a "happy battery", and our users are also happy.
4. The charging and discharging platform is high: The voltage of single lithium battery is 3.6V and that of single nickel metal hydride battery is 1.2V, which is three times that of the latter. The charging method of lithium battery is to set a termination voltage, usually 4.2V for single battery. There is no voltage rise or fall for Ni MH battery. The charging method of lithium battery is called voltage and current limiting method (voltage refers to voltage and current refers to current, i.e. set an upper and lower limit for voltage and current), while the voltage platform of Ni MH battery is low, and it is usually charged with constant current (a constant current). Due to different charging methods, lithium battery charger and Ni MH battery charger cannot be mixed.
5. Specific specifications: The name of special-shaped Ni MH battery is often heard in the market, while special-shaped lithium battery is rarely heard. This is because lithium batteries are mainly used in products with large market capacity. If they are used in markets with small capacity, it is not only technology, but also large cost sharing. However, the problems of technology and market scale are also improving. Some enterprises in the lithium battery industry have been trying to enter the new field of lithium battery application with a positive attitude. For example, Dongguan Juda Electronics Co., Ltd., formerly a manufacturer of lithium battery customization, is carrying out the R & D and production of special batteries, which is the specific measures to comply with this trend, It is believed that similar practices will become one of the common phenomena in the industry in the near future.
Comparing the differences between Ni MH battery and lithium battery from the above five aspects shows the advantages of lithium battery. However, different forms of battery products have their own inevitability due to their different chemical properties, so that they will not be completely replaced by other battery forms, such as carbon electricity, alkali electricity and Ni MH battery. For example, in the field of high current instantaneous discharge, Ni MH battery is better than lithium battery. These fields include medical devices, emergency equipment, electric tools, etc. In larger applications, Ni MH batteries can also be used in new energy hybrid vehicles. Of course, the research in this field needs to be broken through.
