About Self-discharge of Lithium ion Solar Batteries

Lithium-ion solar batteries with inconsistent self-discharge will have a large difference in their SOC after a period of storage, and their capacity and safety will be greatly affected.

What Is The Self-discharge of Lithium-ion Solar Batteries?

Self-discharge of lithium-ion solar batteries is a normal chemical phenomenon, which refers to the loss of charge of a lithium battery overtime when it is not connected to any load. The speed of self-discharge determines the percentage of the original stored power (capacity) that is still available after storage. A certain amount of self-discharge is a normal property caused by the chemical reactions that occur within the battery. Lithium-ion batteries typically lose about 0.5% to 1% of their charge per month.

When we put a battery containing a certain amount of charge at a certain temperature and keep it for a certain period of time, To make a long story short, self-discharge is a phenomenon in which Solar lithium battery itself is lost due to subsidiary Knowledge of self-discharge is important for selecting the right lithium-ion battery system for certain applications.

The Importance Li ion Solar Battery of Self-discharge.

Currently, li ion battery are used more and more widely in laptop,digital camera and other digital devices, besides, it also have board prospects in vehicle, communication base station, battery energy storage power station and some other areas.Under these circumstances,battery is not only show up alone like in just a cell phone but also will show up in series or in parallel.

In the home off-grid solar system, the capacity and life span of the li ion solar battery pack is not just only related to every single battery, but also more related to the consistency between every single li ion battery.Poor consistency can greatly drag the manifestation of the battery pack.

The consistency of the li ion solar battery self-discharge is one of the important part of the effect factor,the SOC of li ion solar battery with inconsistency self-discharge will have a biggish difference after a period of storage and its capacity and security will be greatly affected. It help us to improve the overall level of our li ion battery pack,get longer life and lower the fraction defective of the products through our studying.

What Causes Solar Lithium Batteries Self-discharge?

Solar lithium batteries are not connected to any load when open circuit, but the power is still decreasing, the following are the possible causes of self-discharge.

1. Internal electron leakage caused by partial electron conduction or other electrolyte internal short circuit

2. External electron leakage caused by poor insulation of Solar lithium battery battery seal or gasket or insufficient resistance between external cases (external conductor, humidity).

a.Electrode/electrolyte reaction, such as anode corrosion or cathode recovery due to electrolyte and impurities.

b.Local decomposition of electrode active material

3.Passivation of electrode due to decomposition products (undissolved substances and adsorbed gases)

4. Mechanical wear of electrode or resistance (between electrode and collector) increases with the increase of current in the collector.

5. Periodic charging and discharging can lead to unwanted lithium metal deposits on the lithium ion anode (negative electrode)

6. Chemically unstable electrodes and impurities in the electrolyte cause self-discharge in solar lithium batteries.

7. The battery is mixed with dust impurities during the manufacturing process, impurities can lead to a slight conduction of the positive and negative electrodes, causing the charge to be neutralized and damage the power supply.

8. The quality of the diaphragm will have a significant impact on the self-discharge of solar lithium battery

9.The higher the ambient temperature of the solar lithium battery, the higher the activity of the electrochemical material becomes, resulting in more capacity loss during the same period.

The Influence of Lithium ion Battery for Solar Self-discharge.

1. Self-discharge of lithium ion solar batteries will cause a decrease in storage capacity.

2. The self-discharge of metal impurities causes the diaphragm aperture to block or even pierce the diaphragm, causing a local short circuit and endangering the safety of the battery.

3. The self-discharge of lithium ion solar batteries causes the SOC difference between the batteries to increase, which reduces the capacity of the solar lithium battery bank.

Due to the inconsistency of self-discharge, the SOC of the lithium battery in the solar lithium battery bank is different after storage, and the function of the solar lithium battery is also reduced. After customers get the solar lithium battery bank that has been stored for a period of time, they can often find the problem of performance degradation. When the SOC difference reaches about 20%, the capacity of the combined lithium battery is only 60% to 70%.

4. If the SOC difference is too large, it is easy to cause overcharge and overdischarge of the lithium ion solar battery.

How to Reduce Self-discharge of Li-ion Solar Batteries

It is best to store your lithium solar batteries in a cool but completely dry place, preferably between 10 and 25°C. For additional advice related to lithium battery storage, please read our previous blog site. Some basic actions can be required to reduce unwanted lithium-ion solar battery self-discharge. If you are not completely sure of the power level of your batteries, you can always recharge them. This way, you can make sure your lithium solar batteries are up to the task - and you can get the most out of your lithium solar battery pack day in and day out.

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