Method and device for determining self-discharge of battery pack

Abstract

The invention provides a method and a device for determining self-discharge of a battery pack. The method for determining the self-discharge of the battery pack comprises the following steps: firstly, obtaining the discharge capacity C0 of the battery pack at room temperature; according to the obtained discharge capacity C0, the battery pack is discharged in stages so as to obtain the discharge capacity Cn in each stage, and the discharge operation of each stage of the battery pack is carried out at normal temperature; after the battery pack is charged, at room temperature, the battery pack is subjected to standing and staged discharging, so that the actual discharging capacity Cm in each stage is obtained; and finally, obtaining the self-discharge rate of the battery pack according to the discharge capacity Cn in each stage and the actual discharge capacity Cm in each stage. According to the determination method, two groups of discharge capacitance measurement values are detected, and one group of measurement values is carried out after the battery pack stands and the environment adapts to the temperature, so that the influence of the temperature rise factor of the battery pack caused by discharge on the capacitance measurement error can be reduced; by means of correction calculation of two groups of data, more accurate self-discharge rate of the battery pack can be measured.

Description

Technical field [0001] The present invention relates to the field of battery testing technology, particularly to a method of determining the self-discharge of a battery pack. Further, the present invention further relates to a battery pack self-discharge device to determine. Background [0002] Due to the advantages of high energy density, long service life and high voltage, lithium-ion batteries have been widely used in the rapidly developing new energy market. However, during the storage of a battery, it is often accompanied by an attenuation of capacity, a phenomenon known as the self-discharge of the battery. In general, the self-discharge of lithium-ion batteries is divided into two types: one is the self-discharge caused by the physical micro-short circuit inside the battery, which is generally small and reversible; the other is the chemical reaction, that is, the chemical reaction between the electrolyte and the positive and negative electrodes, which is irreversible. Howe...

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Problems solved by technology

However, the above method does not take into account the influence of temperature changes during the charge and discharge process, and does not eliminate the error caused by this factor, so the self-discharge rate obtained by the test will be inaccurate

[0005] However, as an important indicator of battery performance, self-discharge has strict indicator requirements in terms of battery design verification, product verification, and shipping requirements. If self-discharge cannot be accurately tested, it will affect product performance and even affect to customer use

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