Method for manufacturing solar cell, solar cell, and solar cell module

A solar cell, comprising:

• a semiconductor substrate;
• an emitter layer formed on a surface of the semiconductor substrate, wherein a conductivity type of the semiconductor substrate is opposite to a conductivity type of the emitter layer, wherein the semiconductor substrate and the emitter layer form a PN junction;
• a passivation layer formed on the emitter layer;
• an insulating layer formed on the passivation layer;
• a plurality of busbars formed on the insulating layer, wherein the plurality of busbars extend in a first direction and are arranged at intervals in a second direction, the first direction being different from the second direction;
• and
• a plurality of fingers formed on the insulating layer, wherein the plurality of fingers extend in the second direction and are arranged at intervals in the first direction, wherein each of the plurality of busbars intersects with respective fingers of the plurality of fingers, and the plurality of fingers penetrate the passivation layer and the insulating layer to be connected to the emitter layer,
• wherein the plurality of busbars extend toward the emitter layer, wherein a depth of the plurality of busbars extending into the insulating layer is greater than 20% of a thickness of the insulating layer, a depth of the plurality of busbars extending into the passivation layer is no greater than 90% of a thickness of the passivation layer, wherein a depth direction, a thickness direction of the passivation layer, and a thickness direction of the insulating layer being consistent with a direction toward the semiconductor substrate, and
• wherein the thickness of the insulating layer is greater than or equal to 40 nm and less than or equal to 100 nm.

A string of solar cells, comprising a plurality of welding strips, and a plurality of solar cells, wherein each of the plurality of welding strips is connected to respective busbars of a plurality of busbars, wherein a solar cell of the plurality of solar cells comprises:

• a semiconductor substrate;
• an emitter layer formed on a surface of the semiconductor substrate, wherein a conductivity type of the semiconductor substrate is opposite to a conductivity type of the emitter layer, wherein the semiconductor substrate and the emitter layer form a PN junction;
• a passivation layer formed on the emitter layer;
• an insulating layer formed on the passivation layer;
• a plurality of busbars formed on the insulating layer, wherein the plurality of busbars extend in a first direction and are arranged at intervals in a second direction, the first direction being different from the second direction;
• and
• a plurality of fingers formed on the insulating layer, wherein the plurality of fingers extend in the second direction and are arranged at intervals in the first direction, wherein each of the plurality of busbars intersects with respective fingers of the plurality of fingers, and the plurality of fingers penetrate the passivation layer and the insulating layer to be connected to the emitter layer,
• wherein the plurality of busbars extend toward the emitter layer, wherein a depth of the plurality of busbars extending into the insulating layer is greater than 20% of a thickness of the insulating layer, a depth of the plurality of busbars extending into the passivation layer is no greater than 90% of a thickness of the passivation layer, wherein a depth direction, a thickness direction of the passivation layer, and a thickness direction of the insulating layer being consistent with a direction toward the semiconductor substrate, and
• wherein the thickness of the insulating layer is greater than or equal to 40 nm and less than or equal to 100 nm.