Conductive adhesive is a very promising alternative application technology of battery interconnection welding technology in photovoltaic module products. Conductive adhesive is an environment-friendly solution, and provides advantages that traditional welding interconnection technology does not have, such as lower process temperature, stronger stress characteristics, and avoiding the use of toxic lead. When it is proposed to convert the welding process of battery string production to bonding technology in important processes, it is necessary to conduct in-depth analysis of material characteristics, such as material compatibility and long-term reliability of interconnection in photovoltaic modules.

Therefore, we studied the performance, quality and reliability of the materials: 1) the insulation bonding joint using conductive adhesive, and 2) the interconnection characteristics between the batteries connected with conductive adhesive in the test module. In addition, we have developed new conductive adhesive components with higher polymer connection flexibility to enhance the material's ability to cope with thermal stress loading and delamination. In order to better understand the interaction and influencing factors of related materials, we developed a comprehensive test plan. Thermogravimetric analysis (TGA) and thermal desorption / gas chromatography-mass spectrometry (TD / GC-MS) were used to characterize the exhaust and migration behavior of pure conductive adhesives in volatile low molecular compounds. To this end, we explore the combination of different tape and packaging and backplane materials of single cell test module. The test module is arranged on accelerated aging tests with different combined stress factors, including high temperature and humidity (DH), radiation and thermal cycle (TC).

It can be found from the test results that the electrical characteristics of the components still show good repeatability even though the screen printing and component processing of conductive adhesive are completed by manual operation. All the tape types (AG, bare Cu and SnAgCu) are compatible with the current PV module lamination process without any problems. During the accelerated aging test, 1% and 4% power loss occurred in the single cell connected with conductive adhesive and the six sample cell modules, respectively. Therefore, conductive adhesive has the potential to replace the welding process of battery string. We found that the exhaust phenomenon of molecular compounds is slight, and there is no incompatibility with any kind of solder tape and packaging materials.