With the rise of the solar industry during the past decade, demand for PV systems and their components has increased drastically. Best termed as the Balance of System (BoS), these solar system components are becoming significant and integrated part of the PV industry. The technological advancement in making of each component and constant innovative approach of the solar manufacturers for filling the market with more advanced parts has made it one of the most dynamic in the nation. Off all the solar PV components, Junction Boxes have received a great deal of manufacturer’s attention and utilization in the solar industry, and have now formed a large scaled segment with the majority of solar junction box manufacturers being based in China and India. The solar energy is converted into the electricity by using a lot of components including the solar panels, PV junction box, the solar cell array, the cables, etc. The solar junction box is one of the components which play predominated roles in the solar PV system.
It is an enclosure on the module where the PV strings are electrically connected. Junction box is attached to the back of the solar panel (TPT) with silicon adhesive. It wires the (usually) 4 connectors together and is the output interface of the solar panel. Solar Panel manufacturers install junction boxes directly on to the back of every PV panel and serve as the interface between conductor ribbons on the panel and the DC input and output cables. They contain bypass diodes to protect the PV panel from reverse current during hours of darkness, if the panels are in shade or if covered by debris such as leaves, for instance. The photovoltaic junction box has the advantages of UV ray prevention, high temperature resistance, water prevention (IP67 rated), ozone resistance, long service life, strong short time overload capacity, wear resistance, corrosion resistance, oil resistance, etc. A good junction box keeps corrosion at the terminals to a minimum, as it will exclude water coming in. These advantages allow the Junction Box to be widely used in the fields of solar panel installations.
Is the junction box at the back of the panel important?
An important component in the construction of solar panels is the junction box. Attached to the rear of the solar panel, it serves several important functions. The solar junction box can greatly optimize the electric power so as to improve the whole efficiency of the solar system. It allows the power supply from the solar electricity generation system to be stable and safe for the users to use. Besides, the use of the J-boxes optimizes the whole performance of the solar system so that the solar system can convert the renewable and inexhaustible solar energy into electricity more efficiently to solve the problem of energy shortage.
Considering the bright prospect that the photovoltaic junction box is going to achieve in the near future, it is of great importance for us to know the application status and characteristics of solar junction box. It prevents those wirings and electrical components from directly being exposed in the air. According to different applications, PV junction boxes are classified in four types: silicon junction box, non-silicon junction box, curtain junction box and explosionproof junction box. It is worth noting that the application of PV junction box is wider than other conventional junction boxes. The solar energy has been considered the cleanest energy in the world, the technology of using solar energy has been improved to allow solar PV junction box to work more efficiently in a photovoltaic system. An advanced type of PV junction box is the BIPV junction box; it allows the junction box become part of the building such as solar roof and solar window. It works as an actual roof while absorbing the sunlight and converting it into electrical power.
Standards and Safety Issue
The production of PV junction box involves strict examination procedure to guarantee its quality. The most powerful method of this kind of inspection is the TUL&UL, and every qualified PV junction box is supposed to have the certification of TUL&UL. The solar PV junction box must pass TUV&UL authorizations because the solar energy is so widely used all over the world, and the performance of the solar J-boxes must meet the requirements from the TUV&UL authorizations. The UL has the full name of Underwriters Laboratories which can test the solar PV junction box to make sure if it can meet safety standards.
The TUV has the full German name of TechnischerUberwachungsVerein which is a German organization that can test and certify the solar PV junction box for safety. Once the photovoltaic junction box passes the TUV&UL authorizations, it can be safely used all over the world. TÜV Rheinland audits and issue certificates for the manufacturers of photovoltaic components based on relevant international norms, guidelines and quality requirements, such as IEC 62109, IEC 62093, EN 50521, EN 50548, IP67, as well as national standards such as MNRE guidelines.
Not all solar PV junction box manufacturing enterprises can have the opportunity to be authorized by the TUV&UL. The enterprises should have certain scale that means the production line is reliable and stable and the products are abundant in variety. The PV junction box manufacturing enterprises should have the export entitlement for Germany and America that means the junction box products produced by the enterprises can pass the national safety standard at first. The TUV&UL marks on the PV junction boxes are the passports for the manufacturing enterprises to explore the global market. The PV junction box has taken place of other junction boxes due to its strong competitive strength; it utilizes the clean and limitless solar energy for power supplies.
Equally important are the machine friendly packaging aspects of components. Parts must meet the customer’s particular requirements so they can be presented to the pick-and-place machines without further repacking.Securing and sealing of the junction box on the PV module can be completed, as before, with silicone, which must be applied prior to mounting. Alternatively, to facilitate automated assembly of the box to the PV panel, adhesive double sided tape can also be pre-assembled by Molex so that only the protective foil needs to be removed prior to mounting. This eliminates the time-consuming application of silicone and especially the time required for the silicone to cure.
According to manufacturers, to select the most appropriate type of solar junction box, it is important to place considerable emphasis on the application status of junction box. The reason for this is that different types of junction boxes are quite different from each other in the aspect of specific application. For instance, solar junction box is mainly used for the electrical interconnection between different solar apparatuses such as solar panels and solar cells, etc. Waterproof junction box, on the other hand, is mainly used in those environments which have very strict requirements for waterproof level. Hence, it’s necessary for you to get to know the specific application of the particular type of junction box and make sure that it suits you perfectly.
Back in 2009, the global market size for solar junction boxes was $750 million. In 2014, the figure reached an over-estimated value of $2.3 trillion, twice the size of the $1.4 trillion expectation. And now, due to high demand for solar power systems and the PV components, solar junction box market is expected to witness drastic growth in the coming years.As the Indian market ramps up with cumulative solar capacity of 9 GW, it is expected that the PV components, including solar junction box will become a key pillar for demand growth. Rising electricity demand, high irradiation levels, favorable government policies, and huge investments are supporting growth in the solar industry. 2017 will be a bumper year for the sector in India, as the nation gears up to take the total solar power generation capacity to 15-17 GW by March 2017. This growth in solar sector is sure to forge ahead the demand for PV components and solar junction box in India.
The competition has been tough for Indian electrical component manufacturers, as several companies from China, Taiwan, Malaysia and Thailand continue to sell PV components in India well below their costs, which of course pose a problem for fair competition. However, the advantage for the domestic manufacturers is their local presence clubbed with high quality product offering, which has always been appreciated by the customers. As India pushes to become global manufacturing hub under Make in India initiative, it is projected that the volume of manufacturing by the domestic industry will increase in India- and once this happens, the country would see great opportunities for the good quality-conscious homegrown component manufacturers.
With the increasing demand for the adaptation of solar in the country, it is pretty convincing that the market for the smarter and more efficient junction box will be wide open in the coming years. Indeed, the production of PV junction boxes involves exceedingly strict quality inspection. To be specific, PV junction boxes have to be TUV & UL certificated. As time goes on, the production technology of PV junction box will surely be improved a lot. On the other hand, even more consumers will come to realize the advantages of solar junction box in the future. Thus, we are fully convinced that there will be a bright future for PV junction box.