To be competitive internationally, the photovoltaics (PV) industry needs to cut its module production costs and increase efficiency in the operation of PV systems.
One crucial factor in optimising manufacturing costs is the automation of production processes. However, conventional connection technology is not suitable for highly automated manufacture. Junction boxes as we know them – as ‘black boxes’ – by definition offer very limited opportunities for repowering or for the incorporation of new technologies that may become relevant in the future. New features may be demanded by the market or legislation, and may include performance optimisers and fire shutdown mechanisms.
To address the specific needs of this industry, Lapp Group and FPE Fischer collaborated on the development of the EPIC SOLAR MAP SET connection system, presented as a prototype at Intersolar Europe 2012. By adopting the guiding principle of ‘total design change’, this new approach aims to significantly reduce component, production and operating costs.
The system consists of several components, all made of high-quality, weather- and impact-resistant plastic, which can be individually combined as required to connect PV modules. The standardised components can be assembled and welded fully automatically, and customised solutions for different numbers of strings and different cable lengths can be produced on a single production line. The connection system is welded onto the ribbons that have previously been automatically stripped. The connection points are then sealed with diodes, which can also be done automatically.
Leaning heavily on the principle of flexible production platforms used in the automotive industry, the connection system is based on existing technologies and modular components. The injection moulded and stamped parts allow modular production, making it extremely easy to extend the product range.
Designed with future requirements in mind
In the future, there will be an increasing demand for modules to have the capacity to be upgraded with intelligent new technology to respond to the ongoing development of electronic components, such as power monitoring and power optimisers. Legal requirements for features such as shutdown in case of fire will create additional demand for smart connection technologies.
It makes sense, therefore, to design solar modules with repowering in mind. One must also assume that complex electronic circuits will need to be replaced at some stage during the standard service life of a solar system of around 25 years.
Conventional junction boxes limit the scope for repowering and connected boxes do not provide easy access to the internal workings, if any components have to be replaced. As a result, Lapp and FPE Fischer have eliminated the box and put the previously internal diodes on the outside.
This inside-out design enables the connection components to be flexibly configured with different diodes or electronic components, and also allows modifications or upgrades to the overall system at any time with minimal effort. There are no restrictions on the size and shape of new components, which are inevitable with conventional boxes.
A technological upgrade with performance optimisers (MPP trackers) is particularly interesting, as these optimisers are not always worthwhile for brand new modules, and their potential is only utilised once different levels of degradation of the cells has occurred. For complex electronic components, an additional advantage is that prices are constantly falling.
The EPIC SOLAR MAP SET provides an advantage for module manufacturers and PV system operators in that maintenance costs are considerably lower than with conventional junction boxes and new developments can be incorporated into an existing system at any time, ensuring that systems remain state of the art and deliver optimum performance.
Easy accessibility for PV integrated into buildings
For roof mounted, roof integrated and wall mounted systems, it is especially important for the internal workings of the boxes to be easily accessible. For this purpose, another product – the modular EPIC SOLAR RAZOR – is designed such that its interior can always be accessed without delay. The junction box also allows module manufacture to be optimised.
This aluminium junction box allows the functional components to be easily accessible from the front of the module and safely protected from environmental influences. Functional components such as electronic shutdown of individual modules, performance monitoring and performance optimisers can be replaced quickly when servicing is required, and MPP tracker and other new technologies can be easily retrofitted at a later date.
An additional advantage is that the PV modules can be individually assembled and upgraded ex works, by the dealer or even by the installer. This provides benefits to both module manufacturers and operators of PV systems.
The time and work required to attach conventional junction boxes with adhesive is a crucial cost factor, and the new technology provides advantages here too. As the front and rear halves of the box are secured mechanically, there is no need to wait for the adhesive to cure and work on the module can continue immediately. Automated welding through the solar module simplifies the contacting process.
The use of aluminium also reduces the thermal load and increases the service life many times over compared to conventional plastic junction boxes, particularly as the front section of the box is continuously exposed to direct UV radiation. The junction boxes are watertight in compliance with protection class IP67 to prevent corrosion on the contacts, meaning performance remains at a high level over a prolonged period of time and the risk of arcs is minimised.
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