A method for quickly judging the charge retention (soc) of a lithium iron phosphate battery or a battery pack

Abstract

The invention discloses a method for quickly judging the charge retention (SoC) of a lithium iron phosphate battery (group), which is realized by connecting a control circuit to an external circuit of the lithium iron phosphate battery (group), including an input circuit and Output circuit, the input circuit includes a current amplifier, an analog-to-digital converter, and a single-chip microcomputer; the output circuit includes a relay, a lithium manganate battery, a load, a power management IC, and a switch; when the lithium iron phosphate battery (group) is charged (discharged), The input circuit will automatically analyze its current intensity and issue an instruction to order the relay in the output circuit to close, and the lithium manganate battery will also be charged (discharged) at the specified current intensity; ) into a linear correlation, according to which, the SoC of the lithium iron phosphate battery (group) can be quickly judged by detecting the SOC of the lithium manganese oxide battery. The method of the present invention consumes less time, and the judgment is accurate and fast , easy to operate.

Description

technical field [0001] The invention relates to the field of electrochemistry, in particular to a method for quickly judging the SoC of a lithium iron phosphate battery or a battery pack. Background technique [0002] In recent years, due to the energy crisis, especially the problem of climate warming caused by greenhouse gas emissions, the use of low-emission environmentally friendly energy has become an urgent requirement. Therefore, the development and utilization of clean energy such as solar energy and wind energy have been greatly developed. However, solar energy and wind power generation are all unstable energy sources. The premise of realizing grid-connected power generation is to solve the problem of energy storage; and electric vehicles have the advantages of low emission (or zero emission) and high energy conversion efficiency. And applications have made great progress. Due to the advantages of high working voltage, high specific energy density, long cycle life, ...

AI Technical Summary

Problems solved by technology

However, the state of charge is not a directly measurable parameter, it can only be estimated from the current, voltage, temperature and other available battery information

Since lithium iron phosphate has an obvious phase change interface during charging and discharging, there will always be a long voltage plateau during charging and discharging of lithium iron phosphate battery or battery pack, making the charge of lithium iron phosphate battery or battery pack Estimating retention becomes extremely difficult

[0004] Currently, the easiest way to get a SoC is a full discharge test, but this is an offline method that takes a lot of time and changes the aging of the battery

The currently used online methods include ampere-hour electricity method, circuit model method, internal resistance measurement method, Kalman filter method, etc. These methods are not only complicated but also have large errors.

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