Problem cell identification method

Abstract

The invention discloses a problem cell identification method. The method comprises steps that S10, cell loading is performed; S20, a detection circuit is connected with a cell, the current is detected, and the cell is determined according to change of the current; the current turns small to 0 within the predetermined time, and the cell is determined to be a qualified cell; if the current is underany one of a, b and c conditions, a, the current is bigger than a first predetermined value or is infinitely large; b, the current decreases to a stable value, and the stable value is greater than 0;c, the current is lower than a second predetermined value or is 0, the cell is determined to be a problem cell, and the first determined value is greater than the second determined value; if the current is not under any of the a, b and c conditions, the cell is determined to be a to-be-detected cell. The method is advantaged in that through coordination of the S10 and the S20, the problem cell canbe rapidly and effectively selected, the formation process pass rate can be improved, operation energy consumption is reduced, production efficiency can be further improved, and manpower and materialresources can be further saved.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a method for identifying problem batteries. Background technique [0002] In related technologies, although the control of particulate matter has been included in the control of various processes in the production of lithium-ion batteries, due to the limitations of the production process and the complexity of the source of particulate matter, particle contamination of the battery cannot be avoided. In addition to the serious failure of the normal test process (formation, K-transfer heat coefficient value test, IMP (Impedance-impedance)), the internal short-circuit cells caused by some particles can be identified, and there are no other internal short-circuit cells caused by particles. The identification and interception measures have repeatedly caused serious failures such as zero pressure and low pressure on the client side. [0003] In addition, the withstand voltage test wi...

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Problems solved by technology

[0002] In related technologies, although the control of particulate matter has been included in the various processes of lithium-ion battery production, due to the limitations of the production process and the complexity of the source of particulate matter, particle contamination of the battery cell cannot be avoided

In addition to the serious failure of the normal test process (formation, K-transfer heat coefficient value test, IMP (Impedance-impedance)), the internal short-circuit cells caused by some particles can be identified, and there are no other internal short-circuit cells caused by particles. The discrimination and interception measures have repeatedly caused serious failures such as zero pressure and low pressure on the client side

[0003] In addition, the withstand voltage test will be carried out after the cell is wound, assembled and glued. However, due to the limited capacity of the hi-pot (high potential-high voltage test) station, a small number of cathodes and anodes directly contact the cell and flow into the formation process, and most of them escape the cell. After 5 formation processes, it will be judged as a dead cell in the formation step, which causes a serious waste of electric energy, and a small number of escaped cells will turn into heat and fire, which will bring damage to equipment and production safety.

[0004] In addition, in the process of vacuum baking, liquid injection, free baking and other processes of the battery cell, the water content in the electrolyte and the oxygen content often exceed the standard, etc., due to the presence of impurities such as oxygen and water in this part of the battery, the electrolyte has side reactions Deterioration occurs, which leads to the destruction of the electrochemical system, showing that the formation cannot be charged. Due to the lack of preventive measures in the formation process, there is no process identification or interception measures. This type of battery is judged as a dead battery after 5 formations. It affects the production efficiency of equipment and wastes manpower and material resources

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