Method for measuring state-of-charge of large-capacity battery pack

Abstract

The invention discloses a method for measuring the state-of-charge (SOC) of a large-capacity battery pack in order to solve the problem of inaccuracy in measuring the SOC of a large-capacity battery pack in the prior art. First, the maximum available capacity of each battery cell in a battery string is determined; then the maximum chargeable capacity of each battery cell in the battery string is calculated; then the smallest maximum chargeable capacity and the minimum remaining capacity are found; the maximum available capacity of the battery string is then calculated, and the SOC of the battery string is solved; then the SOC of the large-capacity battery pack composed of a plurality of parallel battery strings can be obtained. The method can accurately obtain the SOC of the battery string, ensures the safe use of the large-capacity battery pack, prolongs the service life of the battery pack, reduces the matching requirement when the large-capacity battery pack is assembled, and has strong practicability.

Description

technical field [0001] The invention relates to a method for measuring the SOC (State Of Charge) of a large-capacity battery pack. Background technique [0002] Generally, the terminal voltage of a large-capacity battery pack LCBP (Large Capacity Battery Pack) can be increased by connecting battery cells or modules in series. Similarly, the capacity of LCBP can be increased by connecting battery cells or modules in parallel, that is, the maximum possible Discharge current. Therefore, through the series / parallel connection of battery cells or modules, the energy exchange capability between LCBP and the outside can be improved, that is, a certain power and energy level can be achieved. At the same time, theoretically speaking, any LCBP can be simplified into a series LCBP (composed of battery strings connected in series) or a parallel type LCBP (composed of battery strings connected in parallel), and each battery string consists of multiple Battery cells or modules are conne...

AI Technical Summary

Problems solved by technology

[0008] However, in actual situations, due to the production process and environmental reasons, the external characteristics of paired battery cells or module pairs cannot be completely consistent

Moreover, during the use of the battery, due to the fact that the heat dissipation conditions and heat generation of the battery are not completely consistent, in addition, there is a positive feedback reaction between the battery cells or modules, and the battery cells or modules in the large-capacity battery pack. This reaction is more prominent, and these factors make the difference between the external characteristics of individual cells or modules greater

As a result, there is no accurate correspondence between the external characteristics of the large-capacity battery pack and its SOC

Therefore, the method of calculating the SOC based on the measurement of the external characteristics of the battery pack is not accurate.

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