Choice of Photovoltaic Panel: The Efficiency Factor
The type, design and configuration of the solar cell all have factors that impact the efficiency of the panel. The purpose of this article is to compare the main technologies of single-sided (monofacial) photovoltaic modules.
The "interdigitated rear contact" or IBC cell technology, adopted since its inception by Sunpower and recently also by Longi, seems destined over time to replace the front contact technology, adopted by all the main producers of cell modules (HJT), TOPcon cells , PERC cells. 60-cell polycrystalline or multicrystalline panels are generally the least efficient, cheapest panels and have practically disappeared from the market for some time.
What Are the 10 Best Most Efficient Photovoltaic Panels
While the previous decade (2010-2020) was characterized by a head-to-head essentially between Sunpower and Sanyo/Panasonic before and (Sunpower – Rec Solar after), the last two years have seen an increase in cutting-edge manufacturers in the race for 'efficiency; we currently have several technologies that offer very similar W/m2 performance, in particular the HJT , TOPcon and HPBC ( Hybrid Passivated Back Contact ) technologies.
panels , always followed by competitors while remaining at the top, have seen themselves caught up, for the first time in decades, by another manufacturer, LONGi Solar , which has equaled the level of efficiency of the renowned Maxeon series. LONGi Solar is only the second manufacturer to release a module with 22.8% efficiency based on a unique hybrid IBC cell design that surprisingly relies on a P-type cell substrate.
The Tenka TKA455M-108 photovoltaic panel is the most efficient panel in the world with a record efficiency of 23.27% followed closely by Jinko JKM610N-72HL4R-V 23.06% , while in third place Jinko JKM595N-72HL4 with a result of 23.03% also surpasses it the threshold of 23%.
Separately we have SunPower Maxeon 440 W and Hi-Mo 6 Scientist 585 W which reach 22.8% and 22.6% respectively
Other high-efficiency panels are the models with N-type HJT cells from Canadian Solar, Meyer Burger and REC Solar while Panasonic (the pioneer of the technology, is out of the game having abandoned direct production at the end of 2022 ) .
Among other next-generation panels with multi-busbar (MBB) semi-cut N-type TOPCon cells from JA Solar, Jolywood and Qcells have helped increase panel efficiency above 22%.
The most efficient panels using N-type cells benefit from a lower rate of light-induced degradation, or LID, of just 0.25% power loss per year.
When calculated over the 25-year panel life, many of these high-efficiency panels are guaranteed to still generate 90% or more of their original rated capacity, depending on manufacturer warranty details.
|6||Canadian Solar||Canadian 445W HJT HiHERO CS6R||445W||22.8%|
|7||SunPower||Maxeon 6||440W||22.8 %|
|8||Longi Solar||Hi-Mo 6 Scientist||585W||22.6 %|
|9||Canadian Solar||CS6R-H-AG||440W||22.5 %|
|10||REC||Alpha Pure R||430W||22.3 %|
|11||SPIC||Andromeda 2.0||440W||22.3 %|
|13||JA Solar||Deep Blue 4.0X||435W||22.3 %|
|14||Jinko Solar||Tiger NEO 60 Cells||480W||22.24 %|
|15||Jollywood||Niwa Light||400W||22.0 %|
Temperature Factor: Which Solar Cell Resists Temperature Best
To evaluate the performance of a panel, however, it is not enough to refer only to the efficiency of the module, given by the ratio between power and surface area; in fact, in addition to the reflectivity and other properties of the glass, or the presence of other construction peculiarities such as the removal of the frame, which avoids the stagnation of water in the lower edge of the module, a solution patented by the manufacturer Dahai, the temperature coefficient Pmax must be evaluated , hot spot technologies, number of bas bars and so on; Since we cannot evaluate the performance of all the modules, we focus our analysis on the cell and precisely on its ability to resist high temperatures, a property measured precisely through the temperature coefficient Pmax . Here is the comparison between some panels:
|Photovoltaic Module Model||PMax coefficient (%/°C)|
|Rec Alpha Pure (HJT)||-0,24|
|CanadianSolar HiHERO CSR-435||-0,26|
|Huasun Himalaya G10 440W||-0,26|
|Longi Hi-Mo 6 Scientist/Explorer||-0,29|
|Sunpower Maxeon 6 (Maxeon Gen 6)||-0,29|
|Jinko Solar Tiger NEO (Type N)||-0,30|
|JaSolar JAM PERC (PERC)||-0,35|
|Tenka Solar (PERC)||– 0.43|
The ratio of the change in electrical performance when the PV panel (or string) temperature decreases or increases by multiples of 1°C, compared to its STC reference temperature (standard conditions) of 25°C.
For example, in the case of the REC, a temperature coefficient of 0.25% per oC means that for every 1oC change in temperature, the panel's voltage, current or power output will change by a quarter of one percent.
Annual Degradation Rate
The annual degradation rate is another important parameter declared by manufacturers to take into account (the lower value is the better):
|Photovoltaic Module Model||Max Annual Degradation Rate (%)|
|Rec Alpha Pure (HJT)||-0,25|
|Sunpower Maxeon 6 (Maxeon Gen 6)||-0,25|
|Jinko Solar Tiger NEO (Type N)||-0,40|
|JaSolar JAM PERC (PERC)||-0,55|
Obviously the product warranty is also important to keep in mind, as Rec Solar offers up to 25 years, Sun Power up to 40 years and others like Energetica up to 20 years, while the cheapest modules do not go beyond 12 years ( Jinko Solar, Ja Solar).
Furthermore, Sun Power has also equipped its Maxeon 6 with 350W Enphase microinverters, a choice which certainly presents undoubted advantages regarding more northern areas and in systems subject to shading and glass opacity, but which can limit the output especially in southern areas where the panel manages to express 100% of the power and sometimes even more. It is important to point out, however, that this "castration" effect of the panel is quite irrelevant to its performance, as the panel's nameplate data tells us that the nominal power of the panel is reached when the irradiation reaches 1000W/m2 in standard conditions, i.e. ideal conditions that occur for a few hours a year, especially in the absence of wind and temperatures around 25°.
Cell Architecture and Interconnection: Shingled Cells vs. Half Cells vs. Whole Cells
The photovoltaic panel market has seen an upgrade from the old whole cells to half-cut cells which have now represented the standard for some time and bring undoubted advantages especially in shading conditions.
The most notable difference between conventional solar cells and shingled solar cells in terms of composition and structure is their interconnection or arrangement.
Each solar panel contains different quantities of cells interconnected or arranged differently depending on the desired power.
In general, conventional modules can contain 32, 36, 48, 60, 72 and 96 cells. The cells are arranged in a rectangular or square shape with spaces between them. Then, using high soldering processes, these spaces are filled with busbars or copper strips that provide the interconnection between the solar cells. Furthermore, traditional cells are commonly connected in series. And in this case another important factor is represented by the number of busbars assigned to transport the current, a number which can vary between 9 and 16; obviously the higher the number, the better the cell performance will be.
On the other hand, shingled modules avoid the use of tape, busbars and soldering processes ; in fact the interconnection is achieved by cutting the cells (using laser technologies) into 3-6 strips which are subsequently assembled into strings by connecting the front edge of each strip to the rear edge of the adjacent one. In such a connection, a suitable electrically conductive adhesive is placed, resulting in no gaps between the strips.
Therefore, this process creates a continuous string of strips, which can be combined with others using tapes and busbars to obtain shingle modules. Furthermore, an important difference is that in this case the cell strings are connected in parallel.
Conventional solar panels commonly have their individual cells wired in series , so when a particular portion of the modules is shaded, a bypass diode will be activated turning off that side of the output and leaving the rest of the cells active, causing power loss.
Conversely, because shingled solar cells are wired in parallel, fewer cells will be affected by the shading effect in one section of the module. This translates into a substantial reduction in energy losses.
Additionally, the use of shingle panels greatly reduces ohmic losses as the current is lower (which also improves temperature performance) compared to traditional ribbon-connected strings due to the smaller “shingle” area.
Ultimately, once these technical aspects have been clarified, the main criterion of choice is always the quality/price ratio.
And you, which panel did you choose? If you haven't already done so, take a look in the photovoltaic modules of our shop!
Happy photovoltaic everyone!