The ongoing demand for high-performance solar panels at a reasonable cost makes solar companies experiment with the structure of solar cells and tweak the module design. To improve the efficiency of the overall module, solar manufacturers optimize not just the solar cell but its entire cell design. One of such modifications or new innovations is incorporating multiple busbars on a panel.

What is the busbar?

In the solar cell, there is a thin rectangular strip printed on front and backside of the solar cell to conduct electricity, that strip is called a busbar. The purpose of the busbar is simple yet crucial as it separates the cells to conduct direct current from the photons and transfer it to the solar inverter to convert the current into alternating current. The busbars are generally made of copper plated with silver(Ag) paste to enhance the current conductivity in the front side and to minimize the oxidation at the backside. Similarly, multiple busbars are used to wire solar cells together to generate high voltage electricity.

A panel with multiple busbars ensures high cost-saving potential as the metallization process will need less amount of silver coating on the front side. Metallization plays a significant role in the fabrication of PV solar cells because the silver coating for deposition of fingers and buses is one of the most expensive steps in cell fabrication. Multi busbar can aid in decreasing the total series resistance of the interconnected solar cells.

Perpendicular to busbars is the metallic and thin grid finger. The fingers aid in the collection of generated current to the busbars. The cumulative power collected by all the busbars with the parallel tab wired cell strings (ribbons) is then delivered to the junction box. A solar cell grid consists of these thin current-collecting/current-delivering fingers and the current-conducting busbars. The key to efficient solar panel design is to strike an optimum balance between the busbar and the resistance/ shading/ reflection losses of fingers.

How do multiple busbars work?

Nowadays, multi busbar cells have become standard in solar panel design. The minimum number of busbars has increased to 9BB from conventional 2BB. Several manufacturers have intensified their efforts a step further and designing 10BB to 12BB panels. They are focusing on designing panels using PERC (Passivated Emitter Rear Contact) cells with a maximum number of busbars in frontside contacts. Multi busbars aid in the reduction of internal resistance losses, which occur due to the shorter distance between the busbars.

In a typical solar cell, the metallization pattern usually has thin silver fingers that are responsible for current collection and transportation to the thick busbars. These busbars are then connected to the ribbons (cell strings coated with copper wires) in the photovoltaic module design. The increase in the number of busbars minimizes the current in each ribbon and hence lessens the resistive losses.

Additionally, the distance that the current has to travel from collection fingers to the busbar is plummeted further reducing the resistance of the solar cell and consequently the losses. This allows curtailing the usage of silver paste – as it is the costliest consumables for a silicon wafer.

The usage of multiple numbers of busbars also saves the panel from microcracking. Micro-cracks generally happen between busbars, the effect of these cracks is thus diminished towards smaller affected cell slices between two busbars. Therefore, if we compare the conventional counterpart modules with 2BB and 3BB cells, the long-term durability and reliability of multi-bus bars in case of micro-cracks are commonly higher.

Dash-line pattern busbars

Solar manufacturers never stop researching and innovating new module designs to cut the production costs and to increase efficiency. One of such recent inventions is panels with dash-line pattern busbars, it reduces the usage of expensive silver paste. These modules are available with 3-dash, 5-dash, 6-dash and even 8-dash busbars.

Studies have shown that these panels are more sensitive, meaning they are prone to cracking and power degradation. Increased number of dash lines cause the accumulation of thermal stress in the panel which result in cracking at the corners of the busbar.

All things considered

In conclusion, the goal of using multi busbar cells is to reduce the resistive losses by minimizing the flow of current in both fingers and the busbars. It has the potential to decrease the silver paste usage by 50-80%, less amount of silver also helps in eliminating the finger shading as well. It also enhances the efficiency of cell performance.

What is BIPV?

Traditionally, solar is mounted on a building’s roof, referred to as building-applied PV. But more architects are learning how to also incorporate solar cells and modules into things like curtain walls, roof tiles and railings known as building integrated photovoltaics (BIPV).

A BIPV system consists of solar cells or modules that are integrated in building elements or material as part of the building structure. This way, they replace a conventional building element, rather than attaching to one. BIPV modules not only generate electricity, they can also provide added functionality to the building. For example, they can provide sun protection, thermal insulation, noise protection or safety.

Where can BIPV be installed?

BIPV provides several benefits when compared to traditional solar panels. First, there are more available surfaces for integrating the solar cells or modules — BIPV is not limited to roof integration. Solar modules can also be integrated into the building’s facade, skylights, railings and more. BIPV also adds to the aesthetics of the building. For example, the materials used for BIPV allow architects to play around with transparency and color. When integrated in ventilated facades, semi-transparent skylights or windows, BIPV can help keep the building cool.

What are the costs associated with BIPV?

In general, BIPV is more expensive than traditional PV systems used for solar power plants. There is some logic to this since the BIPV system has more functions than only delivering electrical power. However, because BIPV serves multiple functions in a building besides producing power, it may save material and installation cost.

What technologies are involved with BIPV?

The main solar cell technologies for BIPV are crystalline silicon solar cells, thin-film silicon solar cells and other thin-film technologies like organic solar cells (OPV) and dye sensitized solar cells (DSC). Crystalline silicon solar is the most mature technology, though thin-film technologies are grabbing a lot of attention because of their flexible character, ease of integration and better response to indirect light.

Organic solar cells are a relatively new technology that is still in the development phase. However, advantages of OPV can be that it’s a light-weight semi-transparent material, it can be coated inexpensively onto curved surfaces and onto glass, and it can be made in various colors or just color neutral. It also has a superior sensitivity to low light intensities, making the technology fit for maritime climates. Also, the technology is less dependent on the incident sunlight angle, which makes it ideal for aspects such as facade integration.

What is the outlook for the BIPV market?

BIPV is still a niche market, but architects are starting to use BIPV elements more frequently in the design of new public and office buildings. New net-zero energy buildings will help drive BIPV demand.

1. What is Electroluminescence(El) testing?
When current passes through solar PV cells, light emission occurs. This phenomenon is called Electroluminescence(EL). Testing of modules using this phenomenon can detect hidden defects in the structure of PV cells. This method makes the current distribution visible in the solar PV module and helps detect defects.

With the help of an EL test, a PV manufacturer can evaluate the structural quality of the PV cells or any other defects generated while handling.

Defects that can be found from EL are as given below:

• Microcracks
• Cell cracks
• Soldering defects
• PID defects
• Diode failure
• Dead cell
• Backsheet scratches
• Wafer defects

2. Defects & Impact of defects in a module identified by EL Image
A brief description on important of EL defects which may lead to performance failure is given as below

a) Microcracks
Microcracks can create an electrical separation, resulting in inactive cell part. Determining the power loss caused by microcracks is difficult. It can have varying to no effect at all. Microcracks in silicon wafers are minute cracks that appear as a result of damage during manufacture, shipping, installation, or operation.

How to prevent microcracks
To prevent solar microcracks, three areas must be addressed namely manufacturing, transportation, and environment. A solar panel manufacturer must acknowledge this preventive area.

The supplier should have the following:

• A well-defined supply chain
• A testing procedure that ensures each module receives EL testing
• A strong reputation

How do microcracks occur
A major cause of microcracks is manufacturing defects. However, there are some natural environmental causes as well that cause microcracks, such as:

• Thermal cycling (variation of temperature between night and day)
• Humidity and freezing
• Cyclic (or dynamic) pressure loads and wind loading
• Heavy snowfall
• Hail

Microcracks can occur during installation as well, due to variety of reasons, such as:

• Stepping on modules or resting other equipment on modules
• Bumping or dropping modules as they are lifted onto the roof
• Installation on a nonplanar surface, which may cause twisting of the mounting frame and place stress on the module

Figure 1: Sample module with multiple micro-cracks

b) What are cell cracks?
Cell cracks cause isolation of region of cells. Cell cracks seem to be more severe, as current doesn’t pass through this area, and these may cause hot spots or thermal dissipations. When current passes through these hotspots, it heats the PV panel and starts damaging the panel. Hence it is necessary to identify these hotspots before they completely damage the panel.

Figure 2: Sample module with cell crack

c) Soldering defects
When the temperature during the soldering process isn’t high enough, cold soldering happens. The cold soldering interferes with the connection between the cell ribbon and the cell tab, preventing electricity from flowing and resulting in a loss of power production.

Due to its importance, solar module manufacturers frequently undertake EL testing twice during the manufacturing process.

If left unchecked, cold soldering can develop into hot spots, lowering the module’s power and causing a fire risk.

Figure 3: Sample module with soldering defects

d) Bypass Diode failure
When a bypass diode fails during the functioning of a module, one of the three cell strings is normally switched off. The outcome is a one-third reduction in output. Within the yield curve of a string, with good radiation conditions, a fall in yield of this magnitude and in numerous modules is frequently found. The essential interface for conducting electricity to the outside is a junction box at the back of a solar panel.

Figure 4: Sample module with diode failure

The bypass diodes inside the junction box enclosure can become short-circuited and burn out if water or dust penetrates the enclosure.

A burned bypass diode or connector might cause the panel to become an open circuit, preventing energy from being transferred forth. The bypass diode failure can be detected with help of EL. These modules should be replaced immediately to avoid junction-box burn or energy yield loss in the plant.

e) Potential Induced Degradation (PID)
Solar panels are typically connected in long series to generate a high system voltage, often exceeding 1000 V, which is used to power solar inverters.

Figure 5: Sample module with PID

The large voltage difference between the grounded frames and solar cells may be too much for low-quality solar cells to manage, causing them to fail. These defects can be identified with help of EL imaging.

f) Dead cells
Dead cells occur when a particular cell stops conducting current. Dead cells may be caused due to mechanical stress, which may have previously caused a cell crack in that area.

Figure 6: Sample module with Dead cell

3. When should a module get inspected for EL?
Now when someone is aware of the defects it is important to know when a module shall get inspected for EL.

a) During production, to check the cell quality of cells and module, and replace whenever required

Why this is important?

• This will help the manufacturers to identify defects in the very first stage and avoid future loss due to batch rejection or warranty claims.
• Benefits to manufacturer: Avoid rejection of batch supply

b) Third-party inspection by portable EL before dispatch.
This will prevent the dispatch of bad quality modules and reject batches before it reaches field.

Why this is important?

• This will give confidence to the asset owners that the modules supplied are of good quality and future problems of module replacement due to manufacturing defects can be avoided.
• Benefits to asset owners: Avoid rejection of batches or modules

c) Pre-installation EL test:
To check transportation and shipping damages. As we know, transportation on Indian roads can be a veritable roller-coaster. As solar modules are made of cells which are up to 100- 500µm, if modules are not handled properly during transportation or modules are not transported properly this may cause micro-cracks or cracks. It is also possible that the transport truck may get meet an accident in the way of transport, in this condition there is a high risk of broken and damaged modules.

Why this is important?

• To claim transport insurance and get the damaged modules replaced.

d) After installation EL test:
Handling at the site may cause module failures during installation. If the modules are not handled properly while fixing or transporting within sites this may cause micro-cracks or module frame damages. Modules can also be dropped accidentally while movement within the site. These may cause cracks or micro-cracks or even breakage of modules. These defects can be identified from EL.

Why this is important?

• EPC contractor may be held responsible for the damages and the modules might get replaced

e) To claim insurance from natural calamities like hailstorms, cyclones, heavy rains, floods etc. The expense of field EL testing is covered by insurance, and it allows you to protect yourself against future losses as a result of this incidence. While you wait for the power loss or hot spots caused by microcracks in the modules to occur, either the micro cracked modules will be replaced or the money will be kept in escrow.

Most crucially, without EL test data, it would be impossible to claim micro cracked PV modules later when power loss or hot patches become apparent. The window of opportunity for asset owners who wait a few years after the incident has occurred closes: Insurance policies specify a specific timeframe for reporting damage caused by force majeure events.

f) Before buying an Asset, before signing on an O&M contract, and for lenders before disbursement

• Before buying an asset knowing the performance of the plant is important. An EL can help in identifying the defects and protecting new owners from potential revenue loss.
• An O&M contractor can always mitigate the risks by knowing the plant and module health and bidding for a PR suitably, so that performance loss LD, due to a factor not under their control, is avoided.
• For lenders, it is important to know the module health before investing. Hence an EL image of the module can predict the current quality of modules at the site.

4. Impact of Defects if not detected?
It is known that the power of the solar panel decreases with an increase in temperature. The crack in a module caused power dissipation at the inactive cell area, as it limits the current passage through the inactive area thus causing higher temperature at the impacted area. In the Indian climate where the module temperature ranges from 35 degrees to 45 degrees Celsius on average, a higher temperature at an inactive area will further cause a reduction in output.

Consider the following possible scenario of a 100MW plant with 350 Wp with 285714 panels in the field.

• Scenario A: Degradation of 5% panel is 1.18% instead of 0.7% due to inactive area in cells (dead cell)
• Scenario B: Degradation of 10% panel is 0.9% instead of 0.7% due to cracks or inactive area due to soldering defects.
• Scenario C: 10% of panels are affected with PID with approximately 5% degradation instead of 0.7%
• In the above scenario, a 100 MW plant will produce only 99.51 MW if few EL defects are left unnoticed.
• There would be a loss of 8.48 lakhs unit loss in a year which may cost around Rs 40 lakhs loss per annum.
• If the above defects are detected, one can claim for warranty, based on defects, and consider the defects in Energy yield calculation to minimize PR guarantee loss.
• If the defects are not identified this may cause further damage to panels and loss may increase every year.

5) Conclusion
In this paper, the types of defects in a solar module, the requirement of the EL test, and the impact of the EL test if not done were discussed. It was described that cracks, micro-cracks, dead cells can cause hotspots in a module which may further degrade the module and may constrain the pre-mature aging of solar plants. This paper described that what is the potential gain of performing an EL test at different stages of the module life cycle and a brief description with all perspectives was given. The impact on energy loss due to undetected EL failure was discussed.

A solar carport is a photon-capturing canopy covering a parking area. While they have some things in common with traditional carports and ground-mounted solar arrays, solar carports have distinct advantages over both.

Any PV contractors looking to expand their reach and grow their operations should consider adding solar carports to their list of installation services. The market is already huge. And with PV panel prices trending downwards and electric vehicle (EV) sales on the rise, demand for solar carports will only increase in the years to come.

This article explains what solar carports are, how they work and why they’re becoming more popular.

What Is A Solar Carport?

A solar carport is a covered parking area with a canopy made from PV panels. Sometimes these carports are designed for a single parking spot – like in residential driveways. Other times, they might be strung together in a series to cover entire commercial parking lots.

Either way, solar carport owners benefit from cheaper and cleaner electricity, while also providing shade and protection for their vehicles.

How Does A Solar Carport Work?

Unlike with traditional PV installations attached to rooftops, ground-mounted PV systems rely on tilted panels installed several feet off the ground.

Solar carport structures use a ground-mounted model – except that the PV panels are installed even higher off the ground to provide enough clearance for parked vehicles. Many solar carports also come with in-built electric vehicle (EV) charging stations so that drivers can top up their batteries when not using their cars.

How Much Does A Solar Carport Cost?

A standard solar carport system costs about $3.45 per watt, with the bulk of these expenses going to:

• The panels themselves, which range from $16,000 to $18,000 on average for a 5kW system
• The solar carport structure used to support the PV panels costs around $2,500
• The labor, wiring and other components that round out the system

While these are rough averages, there are several different factors that might influence the total cost of a solar panel carport. For example, commercial installations tend to be somewhat cheaper per watt due to economies of scale. With current PV panel prices, for example, a business owner should budget closer to $3.45 per watt. By contrast, residential solar carports hover closer to the $4 per watt range on average.

Either way, solar carports are technically more expensive than their rooftop counterparts are, with a traditional residential PV system costing as little as $2.81 per watt to install. However, not every home or commercial property is suited for rooftop solar due to any number of factors, including:

• Excessive shading
• Chimneys, vents, and gables
• Limited rooftop space
• Incorrect orientation

For those with large enough yards, ground-mounted solar is often an attractive option, with prices hovering in the $3.11 per watt range.

Despite their higher costs, however, solar panel carports provide a host of advantages over rooftop and ground-mounted PV systems.

The Benefits Of Solar Carports

Below are just some of the reasons commercial and residential solar carports are increasingly in demand.

1. Reduced Energy Expenses

Solar canopies represent an easy way to turn unused surface areas into mini power plants. Just as with rooftop and ground-mounted solar installations, clients can generate their own clean electricity on-site instead of buying power from the utility company. As a result, solar carport owners benefit from monthly savings – not to mention smaller carbon footprints. Better still, their energy costs stay constant since sunshine remains the same price forever (free).

With enough installed capacity, users can even sell excess solar energy back to their utility providers under incentive programs like net energy metering.

2. More Efficient Use Of Space

Ground-mounted solar installations take up valuable real estate, with the space underneath not providing much benefit. Similarly, the average parking lot isn’t terribly productive (even when cars are parked there).

Solar carports offer the best of both worlds – allowing users to optimize limited real estate by transforming unproductive parking spots into renewable energy-generation machines.

3. Protection From The Elements

In addition to generating cheaper and cleaner electricity for their owners, solar carports also provide protection from the elements:

• On the hottest days of the year, solar carports help shade vehicles – resulting in more comfortable commutes for their drivers
• Solar carports provide protection from rain, sleet, and snow – helping to prolong the useful lifetimes of the vehicles underneath

4. EV-Charging

This is a relatively recent benefit. But solar carports can be integrated with EV-charging solutions:

• Homeowners enjoy peace of mind in knowing that their electric vehicles have fuller batteries whenever they leave their houses
• Business owners who install solar carports with chargers give EV drivers another reason to walk through the door

5. More Power Generation

Although solar carports carry a higher price tag, they are simpler to manipulate and optimize than traditional rooftop PV systems. It’s much easier to reorient a parking spot than it is to reposition an entire roof. And this allows installers to orient their clients’ carports in the optimal direction to maximize sun capture – and by extension, solar power generation, carbon offsets, and monthly savings.

Is A Solar Panel Carport Right For Your Clients?

Solar carports aren’t for everyone. And your own clients may be better off with a conventional rooftop solar installation, provided their home or business has sufficient space and the right orientation.

However, solar carports are an increasingly affordable option that delivers many important benefits. And with demand on the rise, adding solar carports to your renewable energy services is a great way to attract more business and future-proof your operations.

When selecting solar lights for your deck, the first thing to consider is the type of lighting effect you wish to create. Solar lights are available in a variety of styles, from basic solar pathway lamps to decorative solar post cap lights and solar fairy string lamps that provide a warm atmosphere. If you need more functional lighting, you might prefer brighter options like LED solar flood lamp or spotlights that can light up larger areas.

Next, consider where you will place the lights. Since solar lights need direct sunlight to charge, ensure that the locations you choose receive plenty of sunlight during the day. For spots with limited sunlight, look for solar lights equipped with high-efficiency panels or those with longer battery life. Additionally, think about whether you want the lights mounted on walls, deck posts, or integrated into the deck itself. The flexibility of solar lights allows you to arrange them according to your design preferences.

Durability and weather resistance are also key factors to keep in mind. Deck are subject to outdoor elements like rain, wind, and temperature fluctuations, so it’s important to select solar lights that are waterproof and designed to endure various weather conditions. Look for lights with an IP65 rating or higher to ensure reliable performance in rainy or snowy weather. Materials like stainless steel, ABS, or rust-resistant coatings will also enhance the longevity of the lights.

To create a visually appealing and functional deck, it’s important to balance aesthetics with practicality. Choosing the right style and brightness will result in a beautifully lit space that enhances your outdoor environment. Whether you desire soft lighting for a cozy atmosphere or bright lights to illuminate the entire deck, solar lights provide an energy-efficient, eco-friendly option that is easy to install and maintain.

SLD, Solar Lights Do, is a company that specializes in producing and selling high-quality solar lights. We offer a diverse range of efficient and durable solar lighting solutions designed for outdoor use. If you’re interested, please visit us at www.solarlightsdo.com.

As urban areas expand and develop, the need for sustainable and efficient infrastructure solutions is at an all-time high. Solar lights are becoming a crucial element in this shift, providing a clean, cost-effective, and adaptable method for lighting urban environments. Whether in parks, walkways, public squares, or streets, solar lighting is changing the way cities manage energy use and environmental stewardship.

By capturing sunlight during the day, these solar powered LED lights are store energy in integrated batteries, ensuring consistent illumination throughout the night. This not only cuts down on energy expenses but also guarantees reliable lighting in areas that frequently experience power outages. For rapidly developing urban areas, solar lights present a practical solution to address infrastructure gaps.

In addition to their energy-saving capabilities, solar lights enhance safety and liveliness in urban settings. Well-lit public areas help deter crime, promote nighttime activities, and improve the overall living experience for residents. For instance, all in one solar street lamp and solar outdoor security light can be strategically installed in poorly lit neighborhoods, boosting visibility and security without the need for extensive wiring or upkeep.

Furthermore, solar lights support global sustainability initiatives. By decreasing dependence on fossil fuels and reducing carbon emissions, they assist cities in reaching their climate objectives. Many local governments are now incorporating solar lighting into their urban development plans, acknowledging its potential to foster greener, more resilient communities.

For cities aiming to adopt sustainable lighting options, Solar Lights Do provides a variety of high-quality solar lights tailored to meet different urban requirements. Our products merge advanced technology with durability, ensuring dependable performance in any setting. Please visit us at www.solarlightsdo.com to discover how solar lighting can revolutionize your city’s infrastructure.

Bring you a simplified explanation of how a solar system works:

When sunlight falls on the solar panels, the panels' cells absorb these photons, Within the solar panels, the conductor silicon converts the absorbed photons into electrons. This process is known as the photovoltaic effect.

The solar panels produce direct current (DC) electricity, which is a type of electrical current that flows in one direction.

The DC electricity generated by the panels is sent to an inverter. The inverter converts the DC electricity into alternating current (AC), which is the type of electricity used in homes and businesses.

The AC electricity produced by the inverter can now be used to power electrical devices and appliances, or it can be fed into the electrical grid for credit or sale to the utility company.

In some regions, homes and businesses with solar systems can take advantage of net metering. Net metering allows the excess electricity generated by the solar system to be sent back to the grid, and the owner receives credits for the electricity produced. These credits can be used when the solar system is not generating enough electricity, such as during nighttime or cloudy days.

Overall, a solar system allows individuals and businesses to harness the clean, renewable energy of the sun to offset their electricity consumption, reduce their carbon footprint, and save money on utility bills over time.

Electric vehicle charger interface instruction

Electric Vehicle (EV) charger have become increasingly essential as the adoption of electric vehicles continues to rise globally. However, one of the challenges in the widespread deployment of EV charging infrastructure is the difference in charging connectors and interfaces across countries. These differences have been shaped by regional standards, technological advancements, and local regulations.

In Europe, the most commonly used charging interface is the Type 2 connector, which is defined by the European standard IEC 62196. It supports both AC (alternating current) and DC (direct current) charging. Type 2 is preferred because of its fast charging capabilities and safety features, and it is mandated for all public charging stations in the EU. For fast charging, the CCS2 (Combined Charging System 2) connector is widely used, combining both AC and DC charging in a single system.

In the United States, the dominant standard is the SAE J1772 connector, used for AC charging. For DC fast charging, the CCS1 connector is employed, which, like CCS2, supports both AC and DC charging, but it is designed with different pin configurations. Tesla vehicles in the U.S. use a proprietary connector, though they also support the J1772 and CCS1 standards through adapters.

China has developed its own standard, the GB/T connector. The GB/T 20234 standard is used for both AC and DC charging, and it is the primary connector type in China. Unlike the international standards, the Chinese system is not fully compatible with European or U.S. systems, necessitating adapters or additional infrastructure for international users.

In conclusion, the diversity of EV charging connectors across the globe highlights the need for interoperability solutions, such as universal adapters or standardized charging protocols, to make cross-border EV travel seamless and efficient.

Mobile light towers are specialized pieces of equipment designed to provide powerful illumination in various outdoor settings. The towers are made from durable materials like steel and aluminum to hold up against harsh use and weather conditions. LED lamps are energy efficient, long lasting, and can light large outdoor areas easily. Portable light towers are lightweight and easy to transport across worksites. Ideal for outdoor events, roadwork projects, and construction sites.