As the traditional PERCP-type monocrystalline cells in photovoltaic cells are already approaching the ceiling of their efficiency, HJT cells are competing with TOPcon cells for the next-generation mainstream technology route.

PERC

The process flow of PERC battery is relatively simple and the equipment is mature, and the cost is the lowest. The PERC technology is mainly based on the deposition of the passivation layer on the backside and laser grooving. On this basis, the front-side SE laser and optical injection/electrical injection annealing and other processes are added when the process is improved and optimized.

HJT

The full name is crystalline silicon heterojunction solar cells. It is to deposit an amorphous silicon film on crystalline silicon, which combines the advantages of crystalline silicon cells and thin film cells, and has the advantages of high conversion efficiency, low process temperature, high stability, low decay rate, and double-sided power generation.

TOPCon

TOPCon (Tunnel Oxide Passivated Contact) technology is an upgraded technology of PERC. It adopts the composite structure of backside oxide layer + doped polysilicon to form a good passivation contact and comprehensively improve the performance of the battery. The TOPCon cell production line is compatible with most of the existing PERC/PERT production equipment. Adding LPCVD, B expansion and wrapping cleaning equipment can complete the production line upgrade, and the upgrade investment is small.

For the mainstream technical routes of PERC, TOPCon and HJT, we will compare the following aspects

TOPCon VS PERC

1. Advantages:

High efficiency: It is estimated that by the second half of 2023, TOPCon can reach 26.8%, the efficiency of PERC is about 23.5%, and the efficiency difference can reach 3.3 percentage points.

Low attenuation: On the one hand, the TOPCon battery will not drop gears, while the PERC battery will drop 1 to 2 gears after re-testing after a period of time; There is close to 8% power attenuation.

Good long-wave response: PERC only responds well to short-wave, and TOPCon responds well to both long-wave and short-wave.

2. Disadvantages:

High fixed investment: TOPCon equipment investment is 200 million yuan/GW, while PERC is 120 million yuan/GW.

Complex process: TOPCon process is 12 steps, while PERC is 11 steps, and the three new processes added by TOPCon are more complicated and difficult to control.

TOPCon VS HJT

1. Advantages:

Good compatibility: TOPCon's technology is relatively mature and has good compatibility. 8 of the 12 processes are exactly the same as PERC. In the newly added three processes, the designed operation, process window, parameter setting, etc. are the same as those of the original PERC. The approximation is very high.

Low workshop investment: TOPCon is about 200-250 million yuan; HJT investment is about 400-450 million yuan.

Good mass production: It can retain and utilize the traditional P-type battery equipment process to the maximum extent, and can be upgraded and transformed on traditional PERC equipment, and the single GW transformation cost is about 60-080 million yuan.

High efficiency: At present, the efficiency of TOPCon is 0.4pct higher than that of HJT, and it is expected that the efficiency difference may increase by 2023.

Low cost of non-silicon: TOPCon is 0.26-0.27 yuan, while HJT is currently 0.33 yuan.

No battery attenuation: TOPCon has no attenuation either at the battery terminal or the module, but the efficiency of HJT gradually attenuates due to the use of low-temperature gel.

2. Disadvantages:

Long process flow: TOPCon has 12 steps, while HJT has only 5 steps, which means that the corresponding personnel and process complexity of the equipment increase a lot.

Large workshop area: Due to the long process flow, a lot of equipment is required, and the land occupation area is large.