What Is The Life Span Of NiMH Batteries And Lithium Batteries?

I believe many of my friends don’t know what the lifespan of NiMH and Lithium batteries is. For professionals in the battery industry, the life of a battery is measured by the number of battery cycles, while for general consumption, they think it is based on time. The length defines the battery life. Now let’s introduce the life span of Ni-MH battery and Li-ion battery from their respective usage characteristics.

1. How long is the service life of Ni-MH battery

Ni-MH battery life is calculated from the moment it is manufactured. Even if it is not used, it will be discharged at a rate of 0.2%-0.3% every day. After a period of storage, even if it is not recycled, a small part Capacity will be permanently lost, and its life will also be attenuated. Therefore, the storage of Ni-MH batteries should not exceed 1 year. So how long is the service life of NiMH batteries?

Regardless of whether it is a rechargeable battery such as a lithium battery, a lead-acid battery or a nickel-hydrogen battery, the battery life that is conventionally seen is not measured in units of time, but in accordance with certain operating conditions. In terms of the number of charge and discharge cycles, that is to say, if the service life is 100 cycles under the same conditions of use, the life of a frequently used battery must be short in terms of time units.

In terms of normal use, the life of a Ni-MH battery can theoretically be selected for 500 times. Of course, if it is used with low current and light load, it can reach a cycle life of about 800 times. In fact, the life of Ni-MH batteries is mainly affected by the following factors:

1. The influence of operating environment on the life of Ni-MH battery

The actual environment in which the Ni-MH battery is used has a certain impact on its service life. For example, if it is used in a lower temperature environment, the Ni-MH battery will not be used directly, that is, it will not discharge. Even if it is put back to normal temperature, it will be used. The service life of Ni-MH batteries will be much shorter than those that have not been operated in low temperature environments. At present, there are not many nickel-metal hydride batteries that work at low temperatures. For example, the nickel-metal hydride batteries produced by Gripp batteries only work at -20°C. If the temperature is low, they will basically not work. At high temperatures, the quality The better high temperature resistance is also below 80°C. Of course, the life of the Ni-MH battery will definitely be shorter if it is used in an environment beyond the normal temperature.

2. The impact of discharge current on the life of Ni-MH battery

There are large types of nickel-metal hydride batteries: conventional discharge type and high-rate discharge type. That is to say, conventional nickel-hydrogen batteries can only be discharged under specified conditions. If high current discharge is performed, it is easy to cause damage to the battery and its life will naturally become shorter. ; High-rate Ni-MH battery is a high-current discharge battery, so it can achieve a rate-type discharge within the specification, of course, it can also be conventionally discharged. Generally speaking, high-rate discharge batteries have a shorter lifespan than conventional discharge batteries. The main reason is that high-rate discharge damages battery materials.

3. The impact of over-discharge and over-charge on the life of Ni-MH battery

Ni-MH batteries have a certain memory effect, and at the same time they are not very resistant to overcharge and over-discharge. Therefore, if Ni-MH batteries are often over-discharged or over-charged, the memory effect will accelerate and become serious, which will seriously affect The length of life of NiMH batteries.

4. The impact of improper storage on the life of Ni-MH battery

When the Ni-MH battery is not in use, it is not operated in accordance with the use or storage specifications, such as the random placement of the battery or the collision and deformation, etc., which will affect the life of the Ni-MH battery.

Of course, there are many other influences on the life of Ni-MH batteries, which are not listed here. As long as the operation requirements are followed, the life of Ni-MH batteries will generally be close to the theoretical life.

Second, how long is the service life of the lithium battery

Lithium battery life will vary due to different types. In theory, the average life of lithium batteries is more than 500 times. We charge once every 3 days, and the theoretical life of lithium batteries is two to three years. The lifespan of lithium batteries with different types of formulations is different. as follows:

1. Life of soft pack lithium battery

(1) The theoretical service life of the soft-pack polymer lithium battery is more than 500 cycles, used in 3C products, and the service life is 3 to 5 years;

(2) The theoretical service life of the soft-packed lithium iron phosphate battery is about 1500 cycles, charging and discharging at low current, the battery life is more than 10 years, and the service life is about 5 years when discharged at high current;

2. Life of steel shell lithium battery

(1) The theoretical service life of steel shell lithium-ion battery is 300 to 500 cycles, low current discharge, 2 to 3 years;

(2) The theoretical service life of steel-shell lithium iron phosphate battery is about 1,000 cycles, and it is discharged with a small current, about 3 years;

In fact, the way users use lithium batteries is ever-changing. Because of the different conditions of use, the actual service life of lithium batteries will be different. In fact, the number of cycles of lithium batteries is not only affected by the way users use them, but also related to the production technology level and material formula of the lithium battery manufacturers.

In fact, the number of cycles obtained by different cycle systems is completely different. For example, the other conditions above remain unchanged, and only the constant voltage voltage of 4.2V is changed to the constant voltage voltage of 4.1V. The cycle life test of the same type of battery is performed. In this way, this battery is no longer a deep charging method, and the cycle life can be increased by nearly 60% in the final test. Then if the cut-off voltage is increased to 3.9V for testing, the cycle number should be increased several times.

It doesn't make any sense to talk about the number of cycles aside from the rules, because the number of cycles is a measure of battery life, not an end!

Myth: Many people like to use the mobile phone lithium-ion battery to automatically shut down and recharge. This is completely unnecessary.

In fact, it is impossible for users to use the battery in accordance with the national standard test mode. No mobile phone will shut down at 2.75V, and its discharge mode is not a high-current constant-current discharge, but a mixture of GSM pulse discharge and normal low-current discharge. The way.

There is another measure of cycle life, which is time. Some experts have proposed that the lifespan of lithium-ion batteries for general civilian use is 2 to 3 years. Based on the actual situation, for example, 60% of the capacity is used as the end of life, plus the aging effect of lithium-ion batteries, and the cycle life is expressed by time. As reasonable.

After the above detailed answers to the service life of Ni-MH battery and lithium battery, I believe that everyone should have a general understanding of the life of Ni-MH battery and lithium battery. Of course, the factors that affect the service life of the battery are very complicated. , The above only lists the main factors, there are many other secondary factors, such as mechanical collision damage, improper storage damage and so on.