**3. Result and Discussion**

#### *3.1. Power Output Analysis of Initial Cells Applied to Each Sample and Specification of Replacement Cells*

The initial CTM of the cells analyzed above was approximately 1.78% based on power, with the median value of 0.9%, as suggested in the optimized module process published in a previous study, and 2.72% of the CTM value of a general photovoltaic module [41]. The calculated power output of the individual cells was approximately 3.6 Wp, which is approximately 14.8% in terms of cell efficiency. Table 3 lists the initial power output of the cell applied to the module using Equations (1) and (2).


**Table 3.** Initial applied cell grade analysis of sample modules (190 A, 190 B) to be recovered.

As cells of the same grade were already discontinued, a module was repaired using the 3-bus bar cell, which had the lowest power among the cells currently in use. The *Pmax* and cell efficiency of the cell used in the initial manufacture of the module are listed in Table 2. Assuming that the FFs of the module and cell were the same, the cell *Vmp* and *Voc* were calculated by considering the number of cells from the module *Vmp* and *Voc*, and *Isc* and *Imp* were determined using *Pmax* and FF of the cell.

The electrical characteristics of the initial and replacement cells used to restore the modules are presented in Table 4. The tolerance of the initial cell follows that of the module specification sheet.

**Table 4.** Electrical data of initial cell and replacement cell.

