Method for group matching of power lithium-ion rechargeable battery

Abstract

The invention discloses a method for group matching of power lithium-ion rechargeable batteries. The method comprises the following steps: one-step charge and discharge detection is conducted to the power lithium-ion rechargeable batteries and the batteries with capacities larger than lower limit capacity are taken as acceptable batteries; the acceptable batteries are charged to a state with 50-90 percent of rated capacity and the rechargeable batteries with acceptable voltage drop are sorted; the obtained acceptable batteries are fully charged and are connected in parallel for at least 4 hours to enable the voltage difference between any two rechargeable batteries to be less than or equal to 1mV; the obtained rechargeable batteries are connected in series to discharge, the voltage of each rechargeable battery during discharge is acquired and recorded, and the discharge is stopped when the voltage of any battery reaches cutoff voltage; and a voltage difference standard is set according to the number of series batteries required for group matching and the battery voltage at the moment of discharge cutoff, and the batteries with voltage differences within the preset range are matched into a group. Since the parameters of the batteries are measured and sorted under the simulated battery use conditions and the single rechargeable batteries with close characteristics are sorted, the quality of the group matching is improved.

Description

technical field [0001] The invention relates to the technical field of battery detection and sorting, in particular to a method for grouping power lithium-ion secondary batteries. Background technique [0002] With the gradual manifestation of the advantages of secondary batteries, the application range of secondary batteries is becoming wider and wider. At present, most of the power sources used to provide power in electric vehicles, electric tools, mobile power supplies and other devices are combined batteries, such as power lithium-ion secondary batteries. Hundreds of components, so the capacity, internal resistance, self-discharge and other parameters of each single battery in the combined battery must be consistent to ensure the capacity and service life of the combined battery. [0003] There are mainly two kinds of sorting methods commonly used now: (1) Use the specified capacity range for sorting, that is, the selected batteries tend to be consistent in capacity; wh...

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Problems solved by technology

[0004] However, the common disadvantage of the above methods is that the test conditions are single, which is out of the actual use of the battery; this is because the battery pack is generally charged and discharged in series in actual use, affected by factors such as the DC internal resistance of the battery, the same discharge capacity A single battery cannot be fully charged and discharged at the same time, so it often affects the capacity and service life of the battery pack. However, if the DC internal resistance is measured, that is, the test of the DC internal resistance of the single battery is added during the sorting process, it will inevitably cause The loaded down with trivial details of working procedure and the increase of cost; In addition, the equipment used in existing method is expensive, and battery test assembly process is loaded down with trivial details

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