## 1 Introduction  
Photovoltaics (PVs) are a process of direct conversion of solar radiation into electrical energy [1; 2; 3; 4]. The first PV cell was made in 1954 and since then work is underway to improve its construction to increase efficiency, and new materials are being sought. Currently, the vast majority of PV modules produced are built from various types of silicon cells (approximately 90% [5]). However, for silicon, there is an upper theoretical efficiency limit of 29.4% [6]. The latest developments in this area are the construction of a monocrystalline silicon PV cell with a record efficiency of 26.7% [7]. Silicon photovoltaic modules, in which there is a phenomenon of direct conversion of solar energy into electricity, dominate the market and it is estimated that this dominance will last about 10-15 years [5]. However, work is continuing to improve its efficiency, durability, and profitability. The photovoltaic market in Poland has been developing very dynamically recently, and the total installed capacity has already exceeded 1.5 GW [8]. One way to improve performance is to build PV modules from half cells. Due to the double reduction of a single cell in a PV module (by cutting a traditional 156 mm \(\times\) 156 mm cell in half, a 156 mm \(\times\) 78 mm cell is created), a new module was built, made of twice as many half-cells. The half-cells are connected in two strings, which eventually are connected in parallel (Figure 1). As a result, such a PV module has similar values of current and output voltage to a typical one. The half-cell module is divided into six sections, protected by bypass diodes (classic modules had three such sections). The result of using half-cell technology is better electrical and mechanical parameters,resulting in greater energy production. Figure 1a,b shows diagrams of the construction of PV modules of classical construction and made of half-cells, letters A-F are marked with internal division sections, protected by bypass diodes. Table 1 compares the basic parameters of the module that will undergo simulation tests with a similar one, made in classical technology [9]. The analysis of this comparison may raise some doubts as to the reliability of the previously described advantages of modules made of half cells. From the numerical values in Table 1, you can even draw negative conclusions: larger, heavier, and less efficient with similar electrical parameters. Regardless of the construction of the PV modules, their external characteristics, prepared in shaded conditions, are comparable. For the operation of classic PV modules under normal conditions (so-called STC--Standard Test Conditions), the Matlab/Simulink (version 2019b, MathWorks, Natick, MA, USA) \"Solar Cell\" package component was designed and verified [10]. This paper presents only the use of the Matlab/Simulink component \"Solar Cell\" to simulate partial shading of a module made of half cells. It was not the author's intention to verify the component, because it was developed based on the proven double-diode model of the replacement PV cell. There are various concepts in the literature for modeling PV cells/modules. The most common implementations of surrogate models are single-diode [11; 12], double-diode [13; 14], and even three-diode [15] models. Modeling uses different calculation methods [16; 17; 18]. The purpose of this work is to check the suitability of this component for modeling the functioning of a PV module from half cells in various real environmental conditions. Before adding the \"Solar Cell\" component to the Matlab/Simulink package, model equations were saved using standard Simulink components or algorithms that were built in the Matlab script language [19; 20; 21; 22]. Analyzing the problem of modeling, it often turns out that very complex models do not give better verification. This is the case with the three-diode model [15], which is original but does not significantly increase the accuracy of calculations.