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Comparison of lithium batteries and nickel-metal hydride batteries

Time:2020-12-26 Views:291

  The current comparison between lithium batteries and NiMH batteries is mainly as follows:

  The comparison between lithium batteries and nickel-metal hydride batteries is that lithium batteries are more suitable for products with low current (such as mobile phones), but if they are used on products with high current (such as digital cameras), the demand for current is relatively large. , And the power consumption is much larger than that of mobile phones. Lithium batteries are in short supply, so it is better to use Ni-MH batteries with large current, large capacity, high energy density, and large power output.

Comparison of lithium batteries and nickel-metal hydride batteries(图1)

  Comparison of advantages and disadvantages

  lithium battery

  Advantages: There is no memory effect (refers to the phenomenon that if the battery is a nickel-cadmium battery, it is easy to leave traces in the battery and reduce the battery capacity if it is not charged or discharged for a long time. Another explanation is that the battery seems to remember the user’s daily life It’s difficult to change this mode over time and can no longer do large-scale charging or discharging.), light weight.

  Disadvantages: high cost, low current capacity, and intolerant of over-saturation (compared to nickel-hydrogen batteries).

  NiMH batteries

  Advantages: Low price, strong versatility, large current, environmental protection, no pollution, and good stability.

  Defects: Heavy weight and short battery life.

  Comparison of charging modes

  The design of the nickel-hydrogen battery charger and the lithium battery charger are based on voltage in principle, and the charging scheme for the design with or without memory effect is also different.

  In terms of voltage, the charge termination voltage of NiMH battery chargers is generally set to 1.4V, and some chargers can also extend up or down a bit. According to the condition of the battery, if the battery is discharged below 1.1V, it may not be charged. , The highest 1.4V is the upper limit that cannot be broken under normal circumstances. For Ni-MH batteries, discharging at 1.1V is of little significance, because the capacity cannot be supplemented during charging. Lithium battery chargers are generally produced one-to-one, that is to say, a single-cell lithium battery is designed with a rated voltage of 3.6V~3.7V and a charging termination voltage of 4.1V~4.2V. Different series and parallel situations, lithium battery pack design The voltages are not very similar.

  In use, because the internal structure of lithium batteries is different from that of nickel-hydrogen batteries, the constituent materials of lithium batteries are active materials, so there is no memory effect, so avoid overcharging. The nickel-metal hydride battery is different. After a certain period of time, the electrolyte will crystallize, preventing the charger from fully charging. This is when the memory effect begins to take effect. The correct way is to activate. There are two types of activation. One is full charge and discharge without capacity loss. The second is after capacity loss occurs. If the capacity loss is more than 1/10, this is almost unusable. At this time, 1.5 times the charging time can be used to activate the already crystallized substances inside, thereby restarting the nickel-metal hydride battery. Correspondingly, the charging process is also accompanied by an increase in voltage. The termination voltage of the nickel-metal hydride battery charger is designed to be 1.4V. The conditions are prepared for this 1.5 times the charging time.

  Nowadays, some chargers also provide a charging protection method, which adjusts the charging mode according to whether the battery is full or not, which can effectively protect the battery. Lithium-ion batteries can be charged as they are used and have little impact on life. For batteries with fuel gauges such as PPC, it is recommended to charge them after they are discharged to avoid impact. It can be charged at any time and can be disconnected at any time. If the battery is fully charged, the battery life will be affected.

  First, the battery must be fully discharged, which must be discharged for about 24 hours, and then fully charged after it is fully discharged. In this way, multiple cycles will restore the battery capacity and prevent the battery from overcharging unless the battery is damaged. However, to avoid the best way to avoid this phenomenon, it is still recommended that you choose Ni-MH batteries or lithium batteries.

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