Device and method for rapidly detecting self-discharge rate of lithium iron phosphate lithium ion battery

Abstract

The invention discloses equipment and a method for rapidly detecting the self-discharge rate of a lithium iron phosphate lithium ion battery, and relates to the technical field of lithium iron phosphate discharge detection. Comprising a lithium iron phosphate lithium power pack, an energy charging mechanism and a current detection meter which are sequentially installed on the top of a detection lathe, and the energy charging mechanism is sequentially connected with the lithium iron phosphate lithium power pack and the current detection meter in series; the energy charging mechanism comprises an adjusting capacitor base, and the outer portion of the adjusting capacitor base is rotationally connected with a rotating circular ring table. The lithium iron phosphate battery needing to be detected and the capacitor with the energy storage effect are connected in series, so that electric energy discharged by the lithium iron phosphate battery is absorbed by the capacitor, the capacitor and the lithium iron phosphate battery are cut off, and the current amplifier and the current detection meter are externally connected to measure the magnitude of current discharged by the lithium iron phosphate battery in a specified actual range. The lithium iron phosphate batteries are screened by comparing the magnitude of current of the lithium iron phosphate batteries, the time needed by actual screening is shortened through simple mechanical linkage, and the detection efficiency is indirectly improved.

Description

technical field [0001] The invention relates to the technical field of lithium iron phosphate discharge detection, in particular to a device and a method for rapidly detecting the self-discharge rate of a lithium iron phosphate lithium ion battery. Background technique [0002] Lithium iron phosphate is a positive electrode material for lithium ion batteries used in power battery packs. Due to the characteristics of lithium iron phosphate, the discharge platform of lithium ion batteries made of lithium iron phosphate as the positive electrode material is very smooth. Generally, lithium iron phosphate ion The static voltage of the battery after charging is almost always at 3.33V, and the value of the static voltage is basically independent of the degree of charging, and its voltage value is closely related to its crystal structure. The olivine structure is always maintained inside, and the olivine structure only changes very little with the charging and discharging process of...

AI Technical Summary

Problems solved by technology

[0002] Lithium iron phosphate is a positive electrode material for lithium-ion batteries used in power batteries. Due to the characteristics of lithium iron phosphate, the discharge platform of lithium-ion batteries made solely of lithium iron phosphate as the positive electrode material is very flat. Generally, lithium iron phosphate The static voltage of the battery after charging is almost always at 3.33V, and the value of the static voltage is basically independent of the degree of charging. The olivine structure is always maintained inside, and the olivine structure only changes very slightly with the charging and discharging process of the material. Therefore, when the lithium iron phosphate battery is in a shelved state, the battery voltage is always at an equilibrium potential of 3.334V, which cannot be compared with other lithium iron phosphate batteries. Ion batteries judge the state of charge of the battery by voltage, but when used in power batteries and energy storage batteries, it is often necessary to combine multiple cells in series and parallel. When cells with inconsistent self-discharge levels are grouped, the self- A cell with a high discharge rate is easy to over-discharge during the discharge process, and it will cause overcharge of other cells during the charging process. At the same time, a cell with a high self-discharge rate will cause the capacity of the entire battery pack to attenuate, seriously affecting the battery capacity. Chemical properties and service life. The existing screening method on the market is to judge the self-discharge rate by discharging after a long time of storage. This method generally takes 3 to 4 weeks for detection and screening, which reduces the actual screening rate.

[0003] The Chinese invention with the publication number CN103048623B discloses a method for quickly detecting the self-discharge rate of lithium iron phosphate lithium-ion batteries. The voltage of the lithium iron phosphate battery will return to the equilibrium potential. By measuring the battery after it is fully charged or discharged Judging the voltage value at a certain time, the measurement is fast and accurate, which is conducive to greatly improving production efficiency and product quality, and is conducive to the setting of the consistent screening of lithium-ion single batteries, which has achieved the effect of improving the actual screening rate, but there are still Screen the problems that are actually too long, and propose a new solution to solve the above problems

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