CN102707213B - Detection method for failure of encapsulated cells - Google Patents

Abstract

The invention relates to a method for detecting the failure of packaged cells, which has the following steps: a) judging the abnormal type of the component according to the IV curve of the component; Test to determine the position of the suspected failed cell, test the current of the suspected failed cell and adjacent cells, and judge whether the tested cell is current-failed according to the current critical value Im; c) If judged according to the IV curve of the module, there is a voltage problem in the module If the abnormality is caused, measure each string in the module in sections to find out the part with low voltage. After finding out the part with low voltage, test the voltage of the cells with low voltage one by one, and judge according to the voltage threshold Vm Check whether the tested cells have voltage failure. The beneficial effects of the invention are: quickly judge the type of failure of the packaged battery according to the needs of customers, and ensure that the electrical properties of the components meet the requirements of customers.

Description

Detection method for cell failure after packaging

technical field

The invention relates to a method for detecting failure of packaged battery slices.

Background technique

With the intensification of market competition, customers have higher and higher requirements on the quality of components. On the instruments that characterize the intrinsic quality of components, EL (Electroluminescence) test is often called the eyes of photovoltaic components, which is used to inspect the microscopic defects of components. , reducing the risk of missed detection.

Contents of the invention

The technical problem to be solved by the present invention is: to provide a detection method for the failure of packaged battery slices, which can combine customer requirements to judge whether the packaged battery slices are invalid.

The technical solution adopted by the present invention to solve the technical problem is: a detection method for the failure of the battery after packaging, which has the following steps:

a) According to the I-V curve of the component, it is judged whether the abnormal type of the component is caused by the current problem or the voltage problem;

b) If judging from the I-V curve of the module, there is an abnormality caused by the current problem in the module, the module judges the position of the suspected failed cell through the EL test, tests the current of the suspected failed cell and adjacent cells, and judges the test according to the current critical value Im Whether the current of the battery is invalid, the current of the battery is greater than Im, the battery is normal, the current of the battery is less than Im, and the current of the battery is invalid;

c) If judging from the I-V curve of the component, the component has an abnormality caused by a voltage problem, measure each string in the component in sections to find out the part with low voltage, and test the low voltage piece by piece after finding out the part with low voltage Part of the battery voltage, according to the voltage threshold Vm to judge whether the voltage of the tested battery is invalid, the voltage of the battery is greater than Vm, the battery is normal, the voltage of the battery is less than Vm, the battery voltage is invalid;

The method to obtain Im and Vm is as follows: first, irradiate the cells of the same efficiency segment under the same light source conditions, and test the corresponding current value Im and voltage value Vm when it works normally and reaches the minimum power Pm required by the customer, and then Im and Vm are used as critical values.

In order to better reflect the actual working environment of the actual cell, when testing the lowest power Pm, the setting range of the illuminance is 700~1000wm/cm2.

The beneficial effect of the invention is: quickly judge the failure type of the packaged battery according to the customer's demand, and ensure that the electrical performance of the component meets the customer's demand.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Figure 1 is the I-V curve diagram of the module;

Figure 2 is a schematic diagram of the component EL test image;

Detailed ways

The abnormal I-V curve of the module directly affects the output electrical performance of the module. Quickly checking the cause of the abnormality can reduce the package loss of the module and the current mismatch of the battery sheet, and reduce the time and difficulty of repairing the module. According to the equivalent circuit model of the solar cell, the curve near VOC can be approximated as a straight line, and the slope of the straight line is Rs, and the curve near Isc can also be approximated as a straight line, and the slope of the straight line is Rsh, the expression as follows:

I=0;

As shown in Figure 1, the I-V curve of the component and the corresponding Pm, Im, Vm, the approximate constant current source segment on the left side of Pm, and the approximate constant voltage source segment on the right side, the abnormality of curve 1 can be regarded as caused by the abnormal current problem, the curve 2 can be regarded as caused by an abnormal voltage problem. Pm=Im*Vm, Pm is the maximum output power, Im and Vm are the current and voltage corresponding to the maximum output power point;

If judging from the I-V curve of the module, there is an abnormality caused by the current problem (curve 1 problem) in the module, at the position of the failed cell judged according to the EL test, that is, the dark position in Figure 2, connect the positive and negative terminals of the tester to the battery The positive and negative poles of the battery are measured, and the type of failure of the battery is determined according to the reference table;

If judging from the I-V curve of the module, the module has an abnormality caused by a voltage problem (curve 2 problem), connect the positive and negative terminals of the tester to the positive and negative electrodes of the battery string, and use the module tester to first analyze each string in the module. Segment measurement, find out the part with low voltage, and determine the type of cell failure according to the reference table. The failure types are: voltage failure and current failure.

Reference comparison table:

To make this table, firstly, the cells of the same efficiency segment are irradiated under the same light source conditions, and the setting range of the irradiance is 700~1000wm/cm2. The current value Im and the voltage value Vm, with Im and Vm as critical values.

For example: the minimum power required by the customer is 4.05 (7.95*0.51), and the reference comparison table is:

Claims (2)

1. A detection method for cell failure after packaging is characterized in that: it has the following steps: a) According to the I-V curve of the component, it is judged whether the abnormal type of the component is caused by the current problem or the voltage problem; b) If judged according to the I-V curve of the module, there is an abnormality caused by the current problem in the module, the module judges the position of the suspected failed cell through the EL test, tests the current of the suspected failed cell and the adjacent cells, and judges the test according to the current critical value Im Whether the current of the battery is invalid, the current of the battery is greater than Im, the battery is normal, the current of the battery is less than Im, and the current of the battery is invalid; c) If judging from the I-V curve of the component, there is an abnormality caused by the voltage problem in the component, measure each string in the component in sections, find out the part with low voltage, and test the low voltage piece by piece after finding out the part with low voltage Part of the battery voltage, according to the voltage threshold Vm to judge whether the voltage of the tested battery is invalid, the voltage of the battery is greater than Vm, the battery is normal, and the voltage of the battery is less than Vm, the voltage of the battery is invalid; The method to obtain Im and Vm is as follows: first, irradiate the cells of the same efficiency segment under the same light source conditions, and test the corresponding current value Im and voltage value Vm when it works normally and reaches the minimum power Pm required by the customer, and then Im and Vm are used as critical values. 2. The method for detecting failure of packaged cells according to claim 1, characterized in that: when testing the minimum power Pm, the setting range of irradiance is 700-1000w/m ² .