Obtaining to the base of TOPCon destruction– pv publication International

From pv publication 09/23

Technical innovation proceeds apace, in a solar sector that might include 400 GW of generation ability in 2023. This year might be as critical as 2016, when passivated emitter back ccontact (PERC) solar batteries replaced back surface area area innovation. TOPCon solar batteries are the front jogger to come to be the brand-new mainstream solar method as well as are obtaining on PERC market share. Heterojunction (HJT) as well as back-contact cells are likewise climbing in appeal.

Recalling

In 2016, after PERC had actually currently made substantial invasions, scientists as well as examination laboratories familiarized destruction concerns. They saw that the innovation was specifically vulnerable to: light-induced destruction (COVER) as well as light as well as elevated-temperature caused destruction (LeTID).

Once the origin was determined, cell as well as component makers promptly took on reduction techniques in their manufacturing procedures, guaranteeing PERC cells ought to not experience too much cover as well as LeTID prices.

In mid-2023, scientists as well as screening as well as qualification lab experts started alerting TOPCon components could be a lot more conscious particular destruction devices. The concern is whether the concerns flagged are a measure of fundamental troubles of TOPCon innovation or are an outcome of the products or procedure manufacturing specifications of these very early components not having actually been totally adjusted to the particular requirements of the innovation.

Deterioration monitoring

The alarm system was very first increased by Paul M. Sommeling as well as his partners from Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO). The group from the Dutch research study body carried out wet warmth examinations to research the moisture-induced destruction influence of various encapsulation products on efficiency in bifacial PV components. It discovered that the front-side metallization of adversely doped, “n-type” TOPCon cells seemed a lot more vulnerable to acid- or moisture-induced destruction than favorably doped, “p-type” matchings.

The most recent yearly “PV Component Index record,” released in Might by the Renewable Resource Examination Facility, a third-party screening laboratory, suggested that n-type TOPCon cells might have greater vulnerability to ultraviolet-induced destruction (UVID).

In June, Asier Ukar, supervisor of screening body PI Berlin Spain, articulated worries that makers were not totally knowledgeable about various destruction devices when switching over from PERC to TOPCon cell manufacturing.

pv publication has actually come close to researchers as well as qualification experts at leading institutes to inquire concerning TOPCon destruction concerns. Producers have actually likewise detailed the reduction actions they’re taking.

Key resources

In this very first component of a two-part collection, we intend to take into consideration any type of legitimate worries for TOPCon makers.

Dealing with these facets will certainly call for the sector to execute ideal procedures in order to alleviate the harmful impacts that greater destruction level of sensitivity might involve. It is apparent that TOPCon components ought to not show greater destruction degrees than today’s market leading PERC components reveal over a 30-year life expectancy under real operating problems– occasionally in instead requiring ecological problems.

Any type of fundamental higher-sensitivity connected with the shift from PERC to TOPCon innovation ought to be plainly differentiated from any type of “teething discomforts” in freshly launched TOPCon components that have actually been mounted over the previous 18 months. The term “teething discomforts” would certainly define high quality concerns that develop when brand-new innovations are presented to the marketplace in “variation 1.0” or maybe also in a “variation 0.9.” Such troubles do not always mirror a TOPCon-specific problem yet instead highlight the truth that particular procedures or products, as an example the encapsulants, have yet to be totally enhanced as well as fine-tuned to the particular requirements of TOPCon cell innovation.

Innovation concerns with brand-new items are not special to the solar sector. Some makers might just be a little extremely enthusiastic to bring an item to market, probably at once when the complete credentials as well as optimization actions of all pertinent procedure specifications in manufacturing have actually not been totally finished. Such a strategy efficiently makes clients “beta testers” of the freshly launched items. While this could be a practical growth choice for software application, we consider it harmful for solar items. A “pest repair” for solar components commonly can not be applied by downloading and install a more recent variation, as is popular for software application items. If there is an actual problem after that, typically, the components currently mounted in the area will certainly need to be traded, which is extremely expensive as well as time extensive.

As constantly, a great track record is conveniently tainted. It is difficult as well as lengthy to need to attempt to bring back lost count on. It is difficult to clients that the “teething difficulties” presently being observed with some TOPCon providers are not troubles fundamental in the innovation yet because of an absence of readiness for some makers.

Equally as a chef can not prepare a three-star dish at their 2nd or very first effort only due to the fact that they have actually picked the most effective active ingredients, it shows up rational that it is difficult to release a brand-new cell kind onto market that satisfies all high quality demands without going through a specific understanding contour. Keeping in mind below, obviously, that the called for life expectancy is thirty years as well as even more.

The required optimization regular corresponds to tweaking some procedure specifications as well as recognizing sensible procedure home windows. Such fine-tuning can truly just be attained within a structure of experimentation also if the producer has years of experience in PERC manufacturing as well as was privileged sufficient to have actually chosen the proper expense of products (BoM) from the beginning– which is an art by itself.

The PV sector remains to be under incredible rate as well as expense stress so manufacturers constantly need to consider just how they assemble the BoM for their components; just choosing to constantly take the most effective elements readily available is not financially sensible. Extremely mindful factor to consider has to be provided to any type of decision-making procedure in which top quality “active ingredients” are considered definitely crucial to produce components that will certainly meet efficiency assumptions over 30, 40, or also 50 years. It is required to recognize the factors at which inexpensive options might suffice without threatening this objective.

In regards to the research study carried out by TNO in the Netherlands right into level of sensitivity to particular kinds of destruction in TOPCon cells, the scientists’ cautions fixate 3 locations:

1. Are TOPCon components a lot more conscious water vapor than PERC panels?

We understand that some makers have actually certainly taken added safety measures relative to this destruction device, specifying that they associate this greater level of sensitivity to the rust of the finely-porous glass that is the “glass-frit” in components. The rust apparently happens because of chain reactions in between moisture/acetic acid as well as the silver-aluminum paste as well as glass frit.

Christos Monokroussos, from the screening laboratory TÜV Rheinland Shanghai, differs. “The level of sensitivity of PV components to water vapor access is predominately managed by their encapsulation, as well as to a much minimal level by the cell innovation,” he claims. “We do not anticipate TOPCon components to act substantially various from traditional PV components when it involves water vapor access.”

As a takeaway, one can end that the chain reaction that eventually results in rust, as well as hence destruction, is currently popular. One would certainly consequently presume that makers have actually taken this element right into account from the beginning as well as have actually dealt with it via the correct selection of encapsulant.

2. Are TOPCon components a lot more vulnerable to UV destruction?

To this concern, Monokroussos claims, “Yes, TOPCon innovations show an enhanced level of sensitivity to UV radiation. The destruction is credited to [issues with] surface area passivation, which weakens after being subjected to UV light. TÜV Rheinland is, consequently, creating an inner requirement to resolve UV-induced destruction of TOPCon PV components. Throughout this examination, both faces of a PV component are subjected to an enhanced UV dosage (10 times greater than obtained in IEC 61215 as well as IEC 61730 [standard testing conditions]), which are taken into consideration enough to examine the vulnerability to UV-induced destruction.”

Monokroussos wraps up that makers need to consequently pay unique focus to the proper selection of encapsulant. “Both the front glass as well as the encapsulant act as a UV filter for the solar batteries,” he claims. “Yet given that TOPCon cells are naturally a lot more conscious UV destruction, as well as the UV filtering system capacities of the encapsulant reduces with time as the component is completely being subjected to UV radiation, a much more UV immune encapsulant needs to be picked as well as, commonly, a thicker layer of encapsulant is being taken into consideration.”

3. PI Berlin’s Ukar claims that TOPCon components are a lot more conscious potential-induced destruction polarization (PID-p). Is this sight shared by various other specialists?

” Yes, n-type innovations, as a whole, are a lot more vulnerable to PID-polarization,” validates Monokroussos. “The destruction setting is usually viewed as relatively easy to fix in the area as long as the component’s rear end is subjected to UV light. Typically talking, in many application settings, PV components would certainly obtain some UV light from the back in the area yet there might be various other application situations eg. roof-mounted installments, where the back side does not obtain enough UV irradiation, hence making these components a lot more vulnerable to serious power losses developing from PID-p. Presently, the IEC [International Electrotechnical Commission] functioning team 2, which is the standardization team concentrating on PV, is dealing with a treatment which would certainly enable to recognize the level of sensitivity of PV components to PID-p.”

To sum up the 3 locations of issue, in all situations there are technical reasons that makers ought to pay added focus to these destruction courses. At the very same time, there are likewise options readily available today that do not involve the substantial added expense to have these concerns.

If there are sets of TOPCon components mounted in the area that currently show troubles, it is a lot more a measure of a maker launching their item too soon than an indication of a total issue connected with TOPCon innovation.

It could be alluring to ask yourself as well as take a bleak expectation how much time it will certainly take till all TOPCon makers have actually at some point changed their BoMs as well as manufacturing procedures to suit these existing destruction hazards. We obtained one item of responses from the research study area that we think a lot far better sums up the expectation for the PV sector as it stands on the edge of transitioning from p-type wafers to n-type wafers.

Radovan Kopecek, from International Solar Power Proving Ground Konstanz, mentions that while higher-efficiency cells can be vulnerable to all kinds of destruction, n-type has fundamental benefits.

” N-type product is much less conscious contaminations as well as consequently breaks down much less in the area– if you comprehend what you are carrying out in the procedure,” claims Kopecek. “If you have the procedure in control as well as pick a great BoM (as an example, dual glass as well as POE [polyolefin elastomer encapsulant]), brand-new n-type component innovations will certainly be a lot more secure.

” However, when innovation adjustments take place also promptly, items can be presented to the marketplace also promptly,” Kopecek includes. “The rate stress in the sector is huge as well as presently the overcapacities produced by the quick developments [of production fabs] is not extremely useful. The sector has to find out to play a worldwide PV harmony as well as emphasis much less on solo mastery.”

In the 2nd installation of this collection, we will certainly contrast as well as highlight the various methods being taken by the leading TOPCon makers to resolve these obstacles.