About the differences between the operating temperature and low temperature power of lithium polymer battery

Jan 11, 2019   Pageview:102

Description of the difference between operating temperature and low temperature of lithium polymer battery

 

The lithium polymer battery uses a ruthenium alloy as a positive electrode, and uses a polymer conductive material, polyacetylene, polyaniline or polyp-phenol as a negative electrode, and an organic solvent as an electrolyte.

 

1. The battery rebounds after the battery is cold.

 

The main cause of this voltage rebound phenomenon is the polarization inside the battery. Polarization means that the internal electrochemical reaction speed of the battery is slower than that of the external circuit, resulting in a virtual low voltage phenomenon during discharge. Depolarization rebound occurs after buffering, and this effect is more pronounced when the discharge current increases or the temperature decreases.

 

Polarization curve is shown in the diagram below, when the battery in the open circuit state without an electric current passes through, the potential of electrode potential for balance, when a current through the electrode, the electrode will occur the phenomenon of deviating from the equilibrium electrode potential, known as the electrode polarization.

 

Power management is most directly according to the current voltage value to reflect the current charge, at low temperatures down electricity, because of the action of polarization voltage will have a certain amount of rebound, so power display will have certain degree of volatility difference.

 

2, on the battery operating temperature explanation:

 

Lithium polymer battery charge generally determine the temperature of 0 ~ 45 , in this temperature range, with average current of battery charging difference is relatively small. General reference test battery + - 5 temperature is 23 degrees, higher or lower than the temperature test result will be a little deviation.

 

Lithium ion batteries in the process of charging, lithium ion by the positive emergence into negative, under normal circumstances the cathode of lithium ion embedded and emerge in balance, and when the battery is in low temperature environment, the viscosity of the electrolyte.

 

Lithium ion movement is blocked, the cathode surface of lithium ion embedded out to break the equilibrium state, there will be a part of lithium ion deposition in the cathode surface, formation of lithium phenomenon, resulting in the loss of battery capacity; And when the battery in high temperature environment.

 

The electrolyte and the activity of active material is larger, inside the battery will have side effects, and the development of the electrolyte decomposition, on the one hand, cause the loss of capacity, on the other hand also can produce gas, because of the occurrence of adverse reactions caused by battery ballooning.

 

Aluminum polymer battery discharge temperature is commonly - 10 ~ + 60 , in the temperature range of batteries can be normal discharge, but there are some differences of specific performance or temperature below or above this temperature, as well as the characteristics of the battery, a relatively large.

 

The reason is that the battery is in a low temperature environment, the viscosity of the electrolyte becomes large, the migration speed of lithium ions becomes slow, and the discharge is performed at a relatively low current at a low temperature, and the discharged capacity is relatively reduced; in the high temperature environment, the same as above. The occurrence of the reaction loses capacity and may cause gas to cause swelling. Similarly, the reference test temperature for a typical battery is 23+-5°C, and the results above or below this temperature test will be slightly biased.

 

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