The detection method that encapsulation back battery sheet lost efficacy
Technical field
The present invention relates to a kind of detection method that back battery sheet lost efficacy that encapsulates.
Background technology
Along with the aggravation of market competition, the client requires increasingly highly to assembly quality, and on the instrument that characterizes the assembly inherent quality, EL (electroluminescence) test often is known as the eyes of photovoltaic module, is used to check the microdefect of assembly, reduces the risk of omission.
Summary of the invention
Technical matters to be solved by this invention is: a kind of detection method that back battery sheet lost efficacy that encapsulates is provided, can combines customer requirement, judge whether the battery sheet after the packing lost efficacy.
The technical solution adopted for the present invention to solve the technical problems is: a kind of detection method that encapsulates back battery sheet inefficacy has following steps:
A) according to the I-V curve determination component Exception Type of assembly, be current problems cause unusual, still voltage problem cause unusually;
B) if judge according to assembly I-V curve; There is unusual that current problems causes in assembly; Assembly is judged the position of doubtful dead battery sheet by the EL test; Test the electric current of doubtful dead battery sheet and adjacent cell sheet; Whether electric current lost efficacy to declare the battery sheet of testing according to current critical value Im, and the electric current of battery sheet is greater than Im, and the battery sheet is normal; The electric current of battery sheet is less than Im, and battery sheet electric current lost efficacy;
C) if judge according to assembly I-V curve; There is unusual that voltage problem causes in assembly; Every string in the assembly carries out areal survey; Find out voltage part on the low side, find out after the voltage part on the low side the voltage of the battery sheet of test voltage part on the low side piecewise, judge the whether voltage inefficacy of the battery sheet test according to charge threshold level Vm; The voltage of battery sheet is greater than Vm; The battery sheet is normal, and the voltage of battery sheet is less than Vm, and battery sheet voltage lost efficacy;
The method that obtains Im and Vm is: at first with the battery sheet of efficient section irradiation under equal light source condition, test is in its operate as normal and when reaching the lowest power Pm of customer demand, current corresponding value Im and magnitude of voltage Vm, with Im and Vm as critical value.
For better embodying the actual working environment of actual battery sheet, during test lowest power Pm, the setting range of irradiance is 700 ~ 1000wm/cm2.
The invention beneficial effect is: judge the failure type after the cell package fast according to customer demand, guarantee that the electrical component performance satisfies customer requirement.
Description of drawings
Below in conjunction with accompanying drawing and embodiment the present invention is further specified.
Fig. 1 is the I-V curve map of assembly;
Fig. 2 is an assembly EL test pattern synoptic diagram;
Embodiment
The I-V curve abnormality of assembly directly influences the output electric property ability of assembly, investigates unusual reason fast, can reduce the encapsulation loss of assembly and the not matching property of electric current of reduction battery sheet, reduces time and difficulty that assembly is reprocessed.According to the equivalent-circuit model of solar cell, can be approximated to be straight line near near the curve the VOC, the slope of this straight line is Rs, also can be approximated to be straight line near near the curve the Isc, and the slope of this straight line is Rsh, and expression formula is following:
I=0;
Like Fig. 1 is the I-V curve of assembly and corresponding Pm, Im, Vm, is approximate constant current source section in the Pm left side, and the right side is approximately the constant pressure source section, and curve 1 can be regarded as unusually by current problems and causes unusually, and curve 2 can be regarded as by voltage problem and causes unusually.Pm=Im*Vm, Pm are peak power output, and Im and Vm are respectively peak power output point current corresponding and voltage;
If judge based on assembly I-V curve; There is unusual that current problems (curve one problem) causes in assembly; In the position of judging the dead battery sheet based on EL test, i.e. dark-coloured position among Fig. 2 connects the both positive and negative polarity binding post of tester the both positive and negative polarity of battery sheet; Carry out current measurement, confirm the type that the battery sheet lost efficacy based on reference contrast form;
If judge according to assembly I-V curve; There is unusual that voltage problem (curve two problems) causes in assembly; The both positive and negative polarity of the both positive and negative polarity connection terminal of tester connection battery strings, adopt component tester earlier the every string in the assembly to be carried out areal survey, find out voltage part on the low side; Confirm the type that the battery sheet lost efficacy according to reference contrast form, failure type is: voltage lost efficacy and electric current lost efficacy two kinds.
Reference contrast form:
The making of this form; At first with the battery sheet of efficient section irradiation under equal light source condition, the setting range of irradiance is 700 ~ 1000wm/cm2, and test is in its operate as normal and when reaching the lowest power Pm of customer demand; Current corresponding value Im and magnitude of voltage Vm, with Im and Vm as critical value.
For example: the lowest power of customer demand is 4.05 (7.95*0.51), and reference contrast form is: