Photovoltaic junction boxes: The world of supporting roles in power stations

China's newly installed photovoltaic capacity has ranked first in the world for four consecutive years. During the process of continuous expansion in scale, the cost has also been continuously decreasing. Over the past decade, the cost per kilowatt-hour of photovoltaic power has dropped from 3 yuan to 0.7 yuan now. The era of grid parity is approaching, and the "low-profit era" is approaching. The refined management of power stations has become a consensus in the industry. Besides the "main characters" such as photovoltaic modules and photovoltaic inverters, the "supporting roles" like photovoltaic backsheets and photovoltaic junction boxes cannot be ignored.

Photovoltaic junction boxes are small components in photovoltaic power stations. Currently, their market price is approximately 20 to 25 yuan each, accounting for only about 2.7% of the cost of photovoltaic modules and less than 1% of the entire power station system. It is precisely such a small component that plays a significant role in the safety of photovoltaic power stations. If there is a problem with the product quality, the power station will face the risk of being burned to ashes.

Every industry is a world of its own, and the small junction box is also a microcosm of the photovoltaic industry. After going through the trials of "land-grabbing", "price wars" and "technological iterations", where will the junction box industry go in the future?

The "bodyguard" of photovoltaic modules

The photovoltaic junction box mainly has two functions: the basic function is to connect the photovoltaic module and the load, and to conduct the electrical energy generated by the photovoltaic module through the cable. The additional function is to protect the component, which serves as a bypass protection when the hot spot effect occurs. Therefore, photovoltaic junction boxes are also known as the bodyguards of photovoltaic modules.

However, surveys show that among all power station failures and accidents, those caused by junction boxes and connectors account for over 30%, and diode breakdown in junction boxes makes up more than 65% of all junction box and connector accidents, making it a high-incidence area for faults. This has also led to some users' complaints about the quality of the junction box.

Wang Yu, the executive vice president of Zhejiang Fushalang Energy Co., LTD., which has been dedicated to the junction box industry for many years, believes that most users have misunderstandings about junction boxes. The diode is an important component of the junction box. Under normal circumstances, the diode is in the cut-off state. Only when hot spots appear on the component will the diode conduct.

Wang Yu further explained that in the structure of photovoltaic modules, individual cells work in series. Once one of the battery cells is blocked, the affected battery no longer functions as a power source but becomes an energy consumer. The other unblocked cells will continue to conduct current through them, causing high energy loss, and "hot spots" will appear. When the hot spot effect reaches a certain level, it will reduce the power output of the component and even lead to its scrapping, seriously shortening the service life of the component and posing a hidden danger to the safety of power generation in power stations.

To avoid this problem, bypass diodes are connected in parallel to one or several batteries that are connected in series. The bypass current will go around the blocked battery cells and be transmitted through the diode. This ensures that the photovoltaic power station can continue to generate electricity. When a diode is overwhelmed and punctured, it has "sacrificed" itself to protect the components.

Products for cost reduction and efficiency improvement are seeking intelligence

In 2017, it was the second year of China's 13th Five-Year Plan and also a crucial year for China's photovoltaic industry to move towards grid parity. "Cost reduction and efficiency improvement" has become the main theme of the photovoltaic industry chain.

As for the small component of the photovoltaic junction box, the key to cost reduction and efficiency improvement lies in its core component - the diode.

The classification criteria for junction boxes in the market vary. Fusarang's classification of junction box types based on diodes is widely recognized. Wang Yu introduced that the first-generation product was an axial diode and the second-generation product was a surface mount diode, which is also the most widely used type in the current market. The third generation is module diodes, and the fourth generation is intelligent products.

Generally speaking, for enterprises to reduce costs and increase efficiency, there are two steps. The first step is to reduce the initial investment. When comparing the second and third generation junction box products, the surface mount diode junction box is composed of three diodes and four copper sheets, while the module diode is made up of a single module, reducing material costs and manual soldering costs. With the expansion of production scale, the cost advantage of the third-generation product will become more prominent. Wang Yu predicted that modular diode products would be the main models in 2017-2018.

After the cost gradually bottoms out, deliberately cutting corners to reduce costs will cause harm to the 25-year operation of photovoltaic power stations. At this point, more enterprises have begun to take the path of "efficiency improvement", developing new products through technological innovation. Although this increases the initial cost, by enhancing the power generation capacity of the power station in the later stage, the cost per kilowatt-hour can ultimately be reduced.

The fourth-generation intelligent junction box product of Fushalang is the secret weapon for "increasing efficiency". According to Wang Yu, this intelligent junction box product has added an intelligent chip inside, which can monitor the operating status of each component, meet the requirements of component-level monitoring, detect problems in advance, reduce power generation loss, and increase power generation overall. When the increased power generation offsets or even exceeds the initial cost, the economies of scale will be manifested.

With the continuous development of photovoltaic intelligence, intelligent junction boxes will be the major trend in the future development of junction boxes. Wang Yu predicts that the fourth-generation products will become the mainstream products from 2018 to 2020. After 2020, energy Internet junction box products based on smart grids will witness development.

The industry may witness another reshuffle, with brand effects becoming more evident.

Homogeneous low-price competition seems to have become an inevitable path for the development of all industries in our country. The same is true in the photovoltaic industry. Whether it is photovoltaic modules, photovoltaic inverters or brackets, product homogenization has become a common phenomenon, and the photovoltaic junction box niche market is no exception.

According to Wang Yu's recollection, in 2007-2008, the price of German brand junction boxes was around 200 yuan, and they were at the height of their popularity. It is precisely because of the temptation of the huge niche market and the low technical threshold that domestic small and medium-sized enterprises have flocked in to seize the market. In 2011, there were approximately over 100 enterprises in the market, and then the number soared to more than 200. This was accompanied by low-price competition. In 2009, the price of photovoltaic junction boxes was about 100 to 150 yuan. By 2011, it had dropped to around 50 yuan. In 2013, the price of junction boxes fell to 30 to 40 yuan. Now, the product price has dropped to around 20 yuan.

When homogeneous low-price competition reaches a certain level, a reshuffle is inevitable. A few years ago, the photovoltaic industry was hit by a cold spell. After the market's survival of the fittest, some enterprises gradually lost their competitiveness and withdrew, while some new enterprises with technology, capital and channels squeezed into the market and gained a certain share.

For power station owners, the cost proportion of junction boxes in photovoltaic power stations is relatively low. Generally, products that meet the design requirements of the power station functionally and have guaranteed quality are more favored. This is undoubtedly a strong competitive edge for enterprises that have been engaged in the production of photovoltaic junction boxes for a long time and have already achieved a certain scale and brand effect.

It is understood that there are currently less than 100 photovoltaic junction box enterprises in the market. The industry reshuffle, which is like the winnowing of the sand by the waves, indicates that the junction box industry is moving towards a more rational direction. At present, leading enterprises such as Renhe, Zhonghuan and Fushalang have emerged in the industry, and the trend of branding is gradually showing.

Wang Yu believes that the photovoltaic junction box industry will undergo another reshuffle in the future, and the number of junction box enterprises will remain at around 50 at that time. These enterprises can roughly be divided into two categories. One category has good channels, while the other relies on high-quality products and services to capture the market.