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9BB Half Cell Solar Panels (All You Need to Know)

If you’ve recently shopped for solar panels, you may have heard about 9BB solar panels or half-cut solar panels. Both of these cutting-edge PV technologies have fundamentally changed the way solar panels work.

Solar panels with 9BB half-cut cells are known to perform exceptionally well and have better intrinsic and extrinsic properties compared to full cells, low bus bar modules.

But what really are these technologies all about? Are there any other benefits to 9BB half-cut solar panels? Do they have any limitations? Should you buy 9BB half-cell solar panels today?

In this article, we’ll answer all these questions and discuss the complete details of 9BB half-cell solar panels.

What is a 9BB Half Cell Solar Panel?

The best way to grasp the concept of 9BB half-cell panels is to first get to know what bus bars and half cells are.

Busbar (BB)

A busbar is a thin metal strip that conducts electricity between cells. For most solar modules, the busbars are usually aluminum, copper, tin, or nickel. Silver used to be one of the most common busbar materials but is now being phased out due to its prohibitive cost.

If the number of busbars in a single cell is 9, then the module is referred to as a 9BB solar panel. There’re other busbar numbers such as 5BB, 4BB, and 3BB, but in this article, we’ll focus on 9BB half-cut solar panels.

In 9BB solar cells, the space between busbars is drastically reduced. This means short current length, which translates to reduced losses and better overall performance of the modules.

Half cells

Half cells or half-cut solar cells are silicon solar panels with cells that are cut in half for performance improvement.

Half cells solar panels offer the following benefits:

  • Enhanced module output efficiency
  • Better power production
  • Reduced installation area
  • Increased durability
  • Better adaptability to varying conditions

Thus, 9BB half cells are solar panels with cells cut into halves, which are then put into strings, each with 9 bus bars.

The result of combining half cell technology with 9BB design is solar panels with unparalleled performance.

9BB Half Cell Solar Modules Production Process

  1. The process begins with cutting the solar cells. A laser dicing machine is used to precisely cut the solar cells into halves.
  2. The half solar cells are welded together to form the desired size solar string. In a single string, the half solar cells are welded in series.
  3. The solar glass is laid on the solar strings, followed by the first layer of EVA.
  4. Solar strings are merged, ready for bussing. To maximize performance, half cell strings are welded in parallel.
  5. During bussing, 9 metal strips are welded on each solar cell to form 9BB half cells.
  6. Second EVA layer is added, followed by the second glass layer.
  7. Taping and laminating the solar panels are conducted to provide the modules with additional protection.
  8. The junction box is installed on the module. Usually, a split junction box is used to reduce the loss caused by occlusion.
  9. The quality of the modules is affirmed by doing tests as IV and insulation.
  10. Lastly, the 9BB half solar cells are cleaned and packed.

Characteristics of 9BB Half Cut Cells Solar Panels

Efficiency

One of the major limitations of solar panels is low efficiency, but 9BB half-cell panels prove otherwise.

Typically, these modules have a high power production efficiency of at least 20%. The best thing is, this efficiency is maintained throughout their lifetime.

Power production per footprint

Due to the outstanding performance of 9BB half-cut cell solar panels, the power production per unit area is increased tremendously.

Compared to 5BB solar modules, 9BB solar panels need 5% less installation area. So, if you don’t have much space for solar panel installation, these are the solar panels you should invest in.

Degradation

Microcracks

With 9 busbars in a single solar cell, microcracks issues are eliminated, thus assuring the longevity of the solar cells.

The half cell technology is responsible for reduced microcracks in these solar modules. It prevents the 9 bus bars on each cell from cracking when there’re disturbing external stresses.

PID

9BB half-cut solar panels have no potential induced degradation. With this outstanding feature, these solar panels are a top choice in the market today.

Degradation rate

9BB solar cells have a very low degradation rate since they suffer no residual stresses.

Potential losses

Half cells have half the current that flows in conventional full solar cells. Since power loss is proportional to the square of the current, 9BB half-cell solar panels have the losses reduced by a factor of 4.

While cutting solar cells into two has no effect on electrical resistance, it sure reduces internal losses by 75%.

Resistive losses

Resistive losses are power losses in solar cells that happen during current transport. Practically, they represent the power lost in the busbars.

The good thing about half-cut solar modules is that they reduce the amount of current flowing through them, enabling the remaining current to flow without resistance.

Busbar area

Since the busbars used in 9BB solar panels are thin, they take up less area on the solar panel surface. Compared to 5BB solar cells, the busbar area in 9BB solar cells is around 20% smaller.

Fill factor

As a general rule, the fill factor increases with the increasing number of busbars. Therefore, 9BB solar panels have one of the highest fill factors among most conventionally used busbars.

Shading tolerance

Solar panels with 9BB technology use circular welding strips to minimize shading effects on the solar panel. The split module structure of the cells also reduces shading effects.

The same can’t be said for conventional solar panels that use series wiring.

Note: The high number of solar cells and the increased number of rows in a single 9BB half-cut solar panel translate to minimal overall loss of power even if one of the cells is shaded.

9BB half-cut cells solar panels: Buyers’ Guide

Wattage rating

9BB half-cell solar panels come in a wide range of wattages, so there are a lot of options to choose from.

Most 9BB half-cell solar panels fall between 300 and 500 watts (330W, 340W, 350W, 360W, 365W, 370W, 380W, 420W, 430W, 440W, 445W, 450W), but you can also get some out of this range such as 220W, 550W, 1000W.

Number of cells

Most 9BB half-cell solar panels available on the market today have 120 cells (60×2) or 144 cells (72×2).

The latter produces more wattages, but you can choose any depending on the kind of output you want from your PV system.

Size

For 9BB solar cells, 166mm is the standard length. It is however possible for the module size to vary depending on how many solar cells are used.

Weight

9BB half-cell solar panels have workable weights, so you can be sure installation won’t be too difficult.

Here are a few examples:

  • ZNShine solar 365W, 120 cells 9BB half-cut solar panel weighs 19.5kgs.
  • Greensolar 350W- 380W, 120 cells perc mono half-cut solar panel weighs 20 kgs.
  • Greensolar 400W-450W, 144 cells solar panel weighs 24 kgs.
  • Hetechpower 390W, 144 half cells solar panel weighs 24.5kgs

Cell, glass, and frame type

The common cell types on 9BB solar panels are monocrystalline, perc monocrystalline, and polycrystalline. Perc monocrystalline solar cells offer the best overall performance.

Regardless of the brand, the glass on the solar panels you buy should always be tempered with high transmissivity. The anodized aluminum frame works perfectly for these solar panels.

Coating

A good coating for 9BB half-cell solar panels should be antireflective and sturdy enough to protect the module’s components.

A graphene coating improves the performance of 9BB solar panels and reduces the maintenance cost for these modules, hence is the best option.

Outdoor use compatibility

Solar panels are usually exposed to harsh outdoor conditions, so you should only buy panels that can withstand this.

Half-cut 9BB solar panels need to withstand various weather conditions and harsh environmental elements, such as snow loads and strong winds.

Price

The average cost of 9BB half-cell solar panels is $0.875 per watt. In this regard, a 400W, 144 cells 9BB half-cell solar panel should cost you around $350. Similarly, you may pay up to $400 for a 450 W module.

Warranty

In line with the standard lifespan, 9BB half-cell solar panels should have a warranty of 25 years. However, the product warranty may be as low as 10 years.

What’s included in a 9BB half-cut solar panels kit?

  • The modules- cells number and size should be as you ordered
  • Output cables- vary in size from brand to brand
  • Connectors- usually MC4 connectors

Pros of 9BB Half Cell Solar Panels

High performance

Half cells with 9BB solar panels are best known for their unmatched performance in producing solar power. This characteristic is a function of their larger cells size, enhanced charge flow, and reduced degradation/losses.

Whether you experience shading in your area or have limited space to install solar panels, you can never go wrong with 9BB half-cell solar panels.

Highly convenient reliable solar panels

9BB half-cell solar modules are among the most reliable solar panels available due to their high efficiency, low degradation, and excellent outdoor tolerance.

Furthermore, 9BB half-cut cells solar panels require very little maintenance. As long as they’re installed properly, they’ll continue to generate solar power for as long as they’re expected to last.

Very durable

Solar panels with 9BB half cells have a service life of at least 25 years. This great service life can be attributed to the reduced occurrence of issues such as PID, LID, microcracking, and minimal degradation over time.

Half-cut cells are also smaller in size, making them more physically durable than full-sized solar cells.

And it’s not just about long service life. These solar modules also maintain their rated power throughout their lifespan. The result is a better ROI and an assurance that investing in them is well worth it.

Cons of 9BB Half Cell Solar Panels

High price

9BB half-cell panels are pretty expensive (around $1 per watt of solar panels) and can be quite an investment, especially for small projects.

Though there is a hefty initial investment, the increased performance of these solar panels over their long service lives covers the cost.

Only a few modules can be stringed together

Solar panels with 9BB half cells have half the current flowing through them, which doubles the voltage.

Because of the high voltage, there is a limit to the number of solar panels that can be wired in a string and connected to the inverter.

Extra manufacturing steps and possible defects

Cutting solar cells is an extra step in the manufacturing step of 9BB half-cell solar panels. Sure this carries some benefits, but it also means a high cost of fabrication.

A lot of soldering is also done on 9BB half cells solar panels increasing the potential for bad contacts.

Frequently Asked Questions

Can 9BB half-cell solar panels produce more power?

9BB solar panels with half-cut solar cells boast high productivity, but there’s potential to optimize them even further. This can be achieved by using thinner busbars and large-sized solar cells.

What are the differences between standard 9BB panels and half-cut 9BB solar panels?

FactorStandard 9BB solar panelsHalf-cut 9BB solar panels
Temperature coefficient

Better temperature coefficient (can provide up to 10% more power output at extremely high temperatures)Large temperature fluctuations affect power production significantly
Productivity when shadedBetter performance due to improved intrinsic factorsProductivity is significantly reduced when some cells are shaded
Levelized Cost of Energy (LCOE)Around $0.05/kWhAround $0.06/kWh
Long-term performanceMaintain high power production through their useful life. These panels will produce at least 85% of their rated power after 25 years of usage  Performance degrades with time due to microcracks and localized heating. Produce 70-80% of their rated power at 25 years

Are 9BB solar panels better than 5BB solar panels?

In theory, the more the busbars in a solar cell, the better the performance of the solar module, given optimal conditions. Going with this general rule, 9BB solar panels are better than 5BB solar panels.

Other than the higher number of busbars, 9BB cells and modules are slightly larger than their 5BB counterparts, a factor that improves output performance significantly. Also, 9BB solar panels perform better under shade compared to 5BB solar panels.

Conclusion

9BB half cells solar panels are clearly a revolutionary solar PV technology that addresses the major problems of solar technology – poor performance and poor durability.

Yes, 9BB half-cell solar panels might be among the most expensive solar panels you can buy, but if you consider their long-term benefits, they’re definitely worth it. If you’re looking to install a solar PV system, 9BB half-cell solar modules will give you the best payback period for your investment.

9BB half-cell solar panels are perfect for both home and off-grid applications. Outdoors, these solar panels are perfect for RVs or boats.

Due to their superb performance, 9BB half-cell solar modules will be ideal for anyone facing shading and limited space issues.