Method for the balanced charging of a lithium-ion or lithium-polymer battery

Abstract

The invention relates to a method for the balanced charging of n cells which form a lithium-ion or lithium-polymer battery and which are connected in series. The invention is characterised in that the method consists in monitoring the charge levels of the different cells (1) from the moment (t1) following the beginning of the battery (2) charging operation until said operation ends normally or is interrupted; and, as a function of the pre-evaluation of said charge levels, either powering all of the cells (1) uniformly or balancing the cell (1) charge levels by powering same in a differentiated manner as a function of the current charge levels thereof.

Description

Technical field [0001] The present invention relates to the field of charging of rechargeable batteries, and has as its object a method of charging or balancing battery cells of lithium ion or lithium polymer batteries over time. Background technique [0002] Optimum charging of a battery that includes multiple constituent battery cells poses a difficult problem, especially when the number of cells or battery cells in series is large. [0003] In the case of lithium ion or lithium polymer batteries, in addition to the problem of charging optimization of different cells or battery cells, it also increases the problems caused by overcharging (especially overcharging caused by overheating or overvoltage). The above-mentioned unit may be difficult to compensate for damage. [0004] On the one hand, it is well known that in batteries using lithium ion or lithium polymer cells connected in series, the capacity and performance of each cell or battery cell after charging are different, a...

AI Technical Summary

Problems solved by technology

[0017] Therefore, this condition and the application of the high charging currents used in this case to balance the cells that lack charge lead to overheating of said cells, which can lead to the explosion of these cells in extreme cases

[0018] Finally, the application of high-intensity charging currents accelerates the aging of battery cells, thus reducing their performance

[0019] Also, in higher power applications, battery recharge times (especially for full recharge) are long, even very long

Consequently, it often happens that the effective charging time between the two phases of discharge is too short to terminate the charging operation, so that the charging is interrupted although the imbalance between the cells or cells has not been compensated (in the case according to the prior art , where the balancing system appears at the end of charging)

The repetition of these phenomena leads to a rapid decline in the performance of the battery

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