Modern I-V curve measurement with LED Sun Simulator
The requirements for the inspection of solar modules in production are mainly:
- Fast cycle times
- Cost reduction
We have designed our LED units in such a way that the LEDs can theoretically no longer break during normal operation. This completely eliminates the need to replace bulbs, saves time and reduces costs in the long term.
How is this possible?
- Use of the highest quality LEDs from Japanese manufacturers
- All LEDs are operated well below the maximum current for continuous operation
- Limitation of duty cycle to ≤ 1% (e.g. max. pulse duration of 200 ms with 20 s cycle time)
- Optimal cooling to minimize the thermal load of the LEDs due to the design of the MBJ LED boards
Disadvantages of XENON sun simulators
- > 24.000 USD OPEX cost per year for replacement of degraded XENON lamps
- More maintenance and longer downtimes compared to MBJ LED Sun Simulator
- Significant degradation of the spectrum during life of flash bulb - increase in measurement uncertainty
- Limited suitability for new high efficiency cell concepts (HJT, TopCon,...) due to limited pulse duration < 100 ms
- Significantly worse measurement repeatability than MBJ LEDs - increase in measurement uncertainty
- Higher building/ infrastructure cost due to > 5 m high/ long tower/ tunnel
- Inferior optical performance (spectral match, non-uniformity and LTI) compared to MBJ LED Sun Simulator
- Very limited cost reduction and technology development potential as XENON is mature technology
Lifetime test of MBJ LED light source
To demonstrate excellent stability of MBJ LED light source accelerated lifetime test is carried out.
Conditions:
- cycle time 2.7 s
- flash duration 195 ms
- no adjustment of LED intensity
Preliminary results after 12 million flashes:
(corresponds to 8 to 11 years operation in module production)
- spectral match in all wavelengths very stable
- spectral match still very well within A+ conditions of -12% (blue line) to +12 % (red line).
Summary
1. Amortization of the investment in less than 3 years.
The higher investment cost of the MBJ LED sun simulator pays for itself in less than 3 years because there are no operating costs for flash tubes, maintenance is significantly lower, and measurement uncertainty is reduced.
2. Excellent lifetime
The lifetime ( > 12 million flashes, > 10 years of operation) and stability of the MBJ LED light source is ensured by the technical design and supported by a 5-year warranty for the LED boards.
3. Optical performance and stability
The MBJ LED sun simulator is much better than XENON sun simulators, resulting in lower measurement uncertainty.
MBJ LED sun simulator provides better quality with lower overall cost compared to XENON.