The structure of a solar cell:
1) Tempered glass serves to protect the main power generation components (such as solar cells). Its selection is subject to certain requirements regarding light transmittance: 1. High light transmittance (generally above 91%); 2. Ultra-clear tempered glass treatment.
2) EVA is used to bond and fix tempered glass and the main power generation components (such as solar cells). The quality of transparent EVA material directly affects the lifespan of the module. EVA exposed to air is prone to aging and yellowing, which affects the light transmittance of the module and thus the power generation quality of the module. In addition to the quality of the EVA itself, the lamination process of the module manufacturer also has a great impact. For example, if the EVA adhesiveness is not up to standard, or if the bonding strength between EVA and tempered glass and backsheet is insufficient, it will cause the EVA to age prematurely and affect the lifespan of the module.
3) The main function of solar cells is to generate electricity. The mainstream types in the market are crystalline silicon solar cells and thin-film solar cells, each with its own advantages and disadvantages. Crystalline silicon solar cells have relatively low equipment costs, but high consumption and cell costs. However, they also have high photoelectric conversion efficiency and are suitable for generating electricity outdoors under sunlight. Thin-film solar cells have relatively high equipment costs, but very low consumption and cell costs. Their photoelectric conversion efficiency is only slightly more than half that of crystalline silicon solar cells, but they have excellent low-light performance and can generate electricity even under ordinary light, such as the solar cells on calculators.
4) The function of EVA is as described above; it mainly bonds and encapsulates the power generation unit and the backsheet.
5) The backsheet serves to seal, insulate, and waterproof (generally, materials such as TPT and TPE are used, which must be resistant to aging. Most component manufacturers offer a 25-year warranty. Tempered glass and aluminum alloy are generally fine. The key is whether the backsheet and silicone can meet the requirements).
6) Aluminum alloy protective laminate, which provides a certain degree of sealing and support.
7) The junction box protects the entire power generation system, acting as a current relay station. If a module short-circuits, the junction box automatically disconnects the short-circuited battery string to prevent damage to the entire system. The most critical aspect of the junction box is the selection of diodes; different types of cells within the module require different diodes.
8) Silicone sealant is used to seal the junctions between components and aluminum alloy frames, and between components and junction boxes. Some companies use double-sided tape or foam as substitutes for silicone, but silicone is widely used in China because it is simple, convenient, easy to operate, and very low in cost.
The nominal lifespan of solar panels is generally 20 years or more, which of course requires that the materials and processes used in the panels meet the requirements.
Using batteries for heating is impractical. Consider this: a room that size would require around 10 horsepower for air conditioning alone. To use batteries, you'd probably need at least a 10-square-meter room to store the batteries.
Theoretically, standard solar panels have a lifespan of 20-25 years, but the actual lifespan is uncertain. The lifespan of those generic products with English labels sold on Taobao is even more unpredictable! They might break down in just a few months.
As for your suggestion of using solar energy for heating, it's extremely unreliable. First, solar panels have a very low photoelectric conversion rate; even if you covered your entire roof and walls with panels, it wouldn't be enough to heat a 120-square-meter room. The initial cost of the batteries, panels, and auxiliary equipment would be enough to cover your electricity bills for decades. Furthermore, batteries only last 2-3 years and need to be replaced, which is quite expensive.
Solar cells have a lifespan of about ten years and are easy to replace.
