What Solar Panel Features Improve Cloud Performance | Low Light, Output Stability

Half-piece technology and bypass diodes can make cloudy day weak light power generation amount elevate 15%.

Add install micro inverter independently optimize single board, can prevent local shadow cause whole column cut power, ensure output stable.

Low Light

Pick N-type piece

In 1,000W/m²'s test environment under P-type and N-type cell's photoelectric conversion efficiency both fall in the 22% to 23% range, when the sky cloud layer becomes thick, making the light illumination radiation degree drop to 200W/m², P-type PERC module's absolute efficiency will slide down 4% to 5% to arrive at 18.5% level.

Adopt N-type HJT heterojunction technology's module in the same's 200W/m² light illumination inside can maintain 730mV to 750mV's open circuit voltage, its conversion efficiency still maintains at 21.2% height. Morning 6 half light illumination intensity only has 100W/m² time, one piece nominal power 430W's N-type TOPCon panel actual output power reaches 32W, compare same specification P-type panel's 25W output produced 28% power difference amount.

Take one set installed capacity being 10 kW's home use system as an example, in continuous 15 days' cloudy weather inside, N-type panel total extra emit out 120 degrees electricity. According to every degree of electricity, 0.15 dollars' grid connection electricity price calculate, single month bill extra out 18 dollars' economic profit. N-type cell first year power attenuation rate controlled at 1%, following 29 years, inside every year's attenuation rate is only 0.4%, arrived at number 30 year end time still retain 87.4% output power, ordinary P-type module at number 25 year time's retain power usually only has 84.8%.

· 60 piece layout type's panel under 200W/m² illuminance, short circuit current from 10.5A falls to 2.1A.

· 1500V system voltage under, N-type module's leakage current number value maintains at 0.05mA within.

· Light intensity from 1,000 W/m² weakens to 200 W/m²'s process usually needs 0.5 seconds' inverter response time.

· Two square meters area's module under weak light condition's effective power generation region proportion as high as 98.5%.

Can catch scattered light

Thick heavy cloud layer blocks environment inside 60% to 80% of light rays, all belong to diffuse reflection's scattered light, photons hit panel's incident angle distributes in a 15-degree to 85-degree broad range inside.

The manufacture link uses an alkaline solution at the silicon wafer surface to corrode out height located at 2 micrometers to 4 micrometers between, bottom width 3 micrometers to 5 micrometers' micro pyramid structure. When one beam of diffuse reflection light ray using 60 degrees angle hit one seat 3 micrometers high's pyramid incline plane, physical geometry forms forces photons at adjacent's two pyramids between continuous rebound 2 times to 3 times. Cover at silicon wafer surface that one layer refractive index being 2.05, thickness precisely controlled at 130 nanometers' silicon nitride anti-reflection film, take 400 nm to 1000 nm wavelength range inside's surface overall reflectivity down to 1.2%.

In 150W/m²'s low illuminance scattered light environment inside, carry 3 micrometers pyramid textured surface's panel compared to 7 micrometers conventional textured surface's panel extra capture 12% photons, short circuit current increase 0.4A to 0.5A's number value. One piece rated 420W's panel relies on micro structure in cloudy's afternoon to take actual working current from 2.1A pull up to 2.5A, continuous output 35V's stable voltage, let inverter's continuous run time extend whole whole 50 minutes.

· Environment illuminance at 80W/m² to 150W/m² fluctuates over time, monocrystalline silicon original silicon wafer's reflectivity as high as 35%.

· Through 130 nanometers thickness's coating treatment, wavelength 600nm's visible light transmittance elevated 98.5%.

· Under 25 degrees Celsius working temperature, 0.5A's extra current let the whole piece module's instant output power rise up to 17.5W.

· Towards incident angle deflect 45 degrees' light ray, micro textured surface structure takes internal photon's absorption probability from 72% to 89%.

Look accurate wavelength

Sky inside's cumulonimbus cloud like a physical filter block live 400nm to 700nm visible light frequency band inside 40% to 50%'s energy, 700nm to 1100nm wavelength range's infrared photon penetrate cloud layer's probability high out 35%. Ordinary monocrystalline silicon cell at 800 nm wavelength place's responsivity indicator is 0.3 A/W, upgraded after's IBC back contact cell takes same frequency band's responsivity data pull high to 0.5 A/W.

Take silicon wafer thickness from traditional's 170 micrometers to 130 micrometers, wavelength reach 1150 nm's infrared photon able to penetrate silicon wafer and at distance back surface electrode only 15 micrometers' position produce electron hole pair. Located in a 250W/m² cloudy environment and infrared light proportion reaches 65% of the time, towards the 800nm to 1100nm wave band optimized's panel actual measure power output is 45W, ordinary panel under the same spectrum distribution's output power stays at 38W.

In one complete 12-month observation cycle, statistics obtained 120 cloudy weather's accumulate data, towards longer than 750 nm wavelength sensitive's module brought 8.5% annual power generation amount increase amplitude, for one set of 8 kW scale's roof array extra increased 950 degrees electricity's output.

· Single piece 54 layout type's panel in 250W/m² environment inside every hour collects 12000 joules' infrared heat energy.

· Back plate on 2 millimeters thickness's fluorine film takes 700 nm wavelength's light ray and does second time reflection's probability elevate to 15%.

· 95%'s infrared photon penetrates 100 micrometers depth's silicon base bottom layer time was converted to 0.6V's electric potential energy.

· Absorb 900 nm wave band light ray after, module back plate's local temperature rise amplitude controlled at 1.2 degrees Celsius.

Resistance value must be high

Light illumination radiation degree falls to 100W/m²'s dark moment, cell piece inside produced's photo-generated current will shrink to 1,000W/m² standard condition under's one tenth, number value roughly hovers at 1.3A nearby. Cell's parallel resistance number value decided this 1.3A weak current inside has how much will leak away from the edge, parallel resistance only has 500 ohms' cell will happen 0.2A's internal current leakage.

Adopt wavelength 532 nm's laser equipment at silicon wafer edge cut out one strip width being 50 micrometers' insulation trench, making cell's parallel resistance number value jump rise to 3000 ohms above. Under 3000 ohms' resistance value, 100W/m² illuminance time's leakage current shrinks to 0.03A, 97.6% of electrons get to retain and transport to the external circuit.

By 3000 ohms cell piece encapsulate made's 400W module, in 200W/m² environment inside's fill factor still maintains at 74%'s level, use 500 ohms cell piece's module under same's 200W/m² condition fill factor will slide down to 62%. Maintain 74% fill factor equals every piece panel extra emit out 15W's power, by 20 pieces panel form's 8kW array in as long as 6 hours' cloudy day inside can obtain 300W's power advantage, every day accumulate extra produce 1.8 degrees electricity's energy.

· The environment humidity reaches 85% time, insulation trench inside's leakage current still controlled at 0.04A's lower limit.

· Use 0.2 millimeters wire diameter's soldering ribbon to take cell piece series connect, let module internal resistance drop to 12 milliohms.

· Under 400 W/m² illuminance, 3000 ohms parallel resistance brings conversion efficiency elevation to 1.5%.

· Cell piece edge experience 120 degrees high temperature roast 4 hours after, parallel resistance's variance converges at 50 ohms within.

Control temperature coefficient

Cloudy weather's air temperature is usually 15 degrees Celsius to 20 degrees Celsius between wander, panel surface's actual working temperature from sunny day exposure time's 65 degrees Celsius drop temperature to 25 degrees Celsius.

Standard P-type module's temperature coefficient marked as negative 0.35%/℃, temperature every deviates 25℃ standard value 1℃, power will produce 0.35% fluctuation. N-type module's temperature coefficient shrinks to negative 0.25%/℃, under 15℃'s partial low environment temperature run time, compared to 25℃'s standard test condition, output power will reverse direction increase 2.5%. One set total installed capacity being 15kW's system, in light illumination only being 300W/m², and panel temperature at 18℃'s cloudy morning, P-type system output 1.4kW's power, N-type system relies on 0.1%'s temperature coefficient difference value to take actual output power to 1.52kW.

Every day, from 8 o'clock to 10 o'clock, this two-hour low temperature weak light time period, 0.12 kW's power difference amount can accumulate to produce 0.24 degrees electricity's gap. In as long as 15 years' run cycle inside, low illuminance under's temperature coefficient advantage take inverter's direct current input electricity amount elevate 4.2%, let average return rate from every year's 8% rise up to 8.3%.

· Array inside 15%'s module locate at 15℃ low temperature time, MPPT tracker's scan frequency elevates to every second 20 times.

· 450W micro inverter under 18℃ environment's direct current to alternating current efficiency stable at 96.5%.

· In as long as 30 days' cloudy environment inside, 0.25%/℃'s temperature coefficient takes system's average no fault run time extend 400 hours.

· When wind speed reaches every second 5 meters, panel back surface's heat dissipation speed rate elevates 40%, working temperature further drops 3 degrees Celsius.

Output Stability

One hundred and eighty-two millimeters multiply 182 millimeters' complete silicon wafer at leave factory before was laser cut into 182 millimeters multiply 91 millimeters' two equal portions, module internal's circuit connect way from traditional's 60 pieces full series connect change to 120 pieces half piece series parallel connect structure. Sky on cloud drift pass leading to local region's light illumination intensity from 800W/m² sudden drop to 150W/m² time, half piece structure take working current from 13.1A physical cut off to 6.55A.

Joule's law clearly shows that half the current will make the internal circuit's resistance heat loss proportional shrink 75%, under 35V's output voltage, system temperature rise amplitude from 4 degrees Celsius fall back to 1 degree Celsius. Traditional full piece module in suffer cloud layer edge block bottom 30% area time, overall output current will instantly fall to 0.5A below, leading to rated 400W's panel actual power violent drop to 15W.

Half-piece technology relies on up-down independent two parallel circuits. When the bottom array's cumulonimbus cloud's shadow covers produce high impedance time, the upper half part 60 half pieces can still locate at 300W/m²'s diffuse reflection light illumination inside, maintain 3.2A's stable current, and continuously towards inverter transport 110W's power. Every day, from 3 o'clock to 5 o'clock, the cloud amount increases, the 50% independent power generation mechanism takes system power's fluctuation variance from 280W to 120W, single piece panel every day extra pull back 0.15 degrees electricity's loss.

182 millimeters specification's cell piece physical cut after, 6.55A's low current run state let 50%'s local block only cause 50%'s power loss, completely avoided whole piece panel instant cliff style drop power to 0W's extreme fluctuation.

Extra pave copper wire

Cell piece surface's main busbar quantity from early period's 5 strips increase to 16 strips, even 18 strips, adopt diameter only being 0.25 millimeters' round tin plated copper wire replace originally 0.6 millimeters wide's flat soldering ribbon. Light illumination environment under cloudy weather using every second 50W/m²'s speed rate happens fast violent change, 16 strips main busbar take adjacent two strips collect circuit's physical distance from 30 millimeters large amplitude shorten to 10 millimeters.

When a photon hits a silicon wafer produced's 1.5A weak current needs at silicon base bottom inside move time, 10 millimeters' short distance transmission takes internal series resistance's resistance value down to 15 milliohms, current transmission's along route loss rate was controlled at 0.2%'s extreme low water level. Multi main busbar's dense layout in encounter because of temperature frequent at 15℃ to 40℃ between fluctuate and produced's tiny thermal expansion contraction crack time, possess extreme high's fault tolerance rate.

Even if the cell piece surface appears width being 2 micrometers, length reach 15 millimeters' hidden crack, dense's round soldering ribbon still can provide 85% above's backup conduct pathway, guarantee this region 0.8A's current smoothly flow out, panel's overall output power attenuation was limited at 0.5% within.

In as long as 30 days, the daily average light illumination radiation degree is only 250 W/m², plum rain season, 0.25 millimeters round wire's diffuse reflection effect still can take incident angle being 70 degrees' side direction light ray refract back cell internal, make overall photon utilization rate elevate 1.8%, one set 5 kW's array single month output therefore increased 22 degrees electricity.

Diameter 0.25 millimeters' round soldering ribbon takes the electron transmission path to shorten to 10 millimeters within, in 150W/m²'s light illumination low valley period, 16 strips main busbar can take 1.5A's weak current collect rate stable at 98.2%.

Bypass block

400W level's panel back surface junction box inside standard equipped with 3 rated current being 20A, reverse withstand voltage as high as 45V's Schottky bypass diode. Cloud layer move produced's move shadow using every second 0.5 meters' speed slide pass photovoltaic array surface, was shadow cover's that contain 20 pieces cell's series group, its equivalent resistance will in 0.1 seconds inside from 2 ohms soar to 1000 ohms above.

If there is no bypass channel, this 1000 ohms' high impedance will take the whole panel's 22A's short circuit current dead dead block live, even trigger local temperature as high as 85℃'s hot spot effect. Schottky diode detects abnormal voltage bias after, in 0.05 seconds' extreme short time window inside rapid conduction, bearing 0.4V forward voltage drop's price, guide 6.5A's working current bypass that 33.3%'s fault region. This kind of physical shunt mechanism lets the remaining 66.7% locate at 300 W/m² light illumination under's cell piece continue normal work, maintain 26 V's output voltage and 170 W's power output.

When cloudy weather inside a cloud cluster in 5 minutes after scatter away, local illuminance recovers to 800 W/m², diode at reverse bias voltage reaches 15 V, time instant cut off bypass recovers normal series connect, current recovers to 12 A, output power in one second inside climbs to 380 W. Rely on this 3 tiny's semiconductor module, system under cloudy day environment's average no fault run time extends 1500 hours.

Rated 20A's Schottky diode in 0.05 seconds inside conduct form bypass, bear 0.4V forward voltage drop's price, preserve remaining 66.7% not suffer block region as high as 170W's continuous power output.

Wide voltage input

Light illumination intensity at 200W/m² and 900W/m² between present periodicity being 3 minutes' high frequency oscillation, inverter direct current input terminal's voltage median value will be in a wide range of 300V to 450V's violent up and down swing move. System configured's micro inverter possesses 16V to 60V's extreme wide MPPT working voltage range, able to in early morning light illumination only has 50W/m² time, at panel voltage reach 22V's low threshold instant then start inverter program.

MPPT algorithm controller using every second 50 times, namely 20 milliseconds' scan frequency, continuous detect and lock current's highest electric potential point, even if under input current sudden high sudden low produce 30%'s fluctuation's bad working condition, still can maintain 99.8%'s static tracking precision. In as long as 8 hours' cloudy observation window period, carry wide voltage tracking algorithm's inverter take whole column cell panel's output voltage deviation range strictly control at positive negative 1.5V within, system overall's off grid drop line probability large amplitude lower to 0.05%.

In one day, inside experience 20 times thick cloud block's process inside, wide voltage input's fast response characteristic let originally possible was waste's every time as long as 45 seconds' voltage climb slope period convert to effective's power generation time, on one set rated installed 12kW's roof equipment, every day accumulate pull back about 1.2 degrees electricity's usable energy. According to the 0.2 dollars' unit price, every year on rainy days, the electricity fee profit reaches 85 dollars.