Selective Emitter Solar Cell and Fabrication Method Thereof
A fabrication method of a selective emitter solar cell, including: forming a selective emitter solar cell base having a buried grid electrode; forming an anti-reflection layer on the emitter surface of the solar cell base; forming a bus-bar on the anti-reflection layer; and connecting the buried grid electrode with the bus-bar in the traversing direction underneath through the anti-reflection layer. Accordingly, the invention provides a selective emitter solar cell. With the method of the invention, emitters and bus-bars are made separately, the width of the emitters can be reduced according to actual needs, the area that is unnecessarily taken may be reduced, the effective area for a solar cell panel to receive sunlight may be increased. The invention improves conversion efficiency of a selective emitter solar cell panel from 16.5% to 18% or more.
1 . A method for fabricating a selective emitter solar cell, comprising:
forming a selective emitter solar cell base having a buried grid electrode;
forming an anti-reflection layer on the emitter surface of the solar cell base;
forming a bus-bar on the anti-reflection layer; and
connecting the bus-bar with the buried grid electrode in the traversing direction underneath through the anti-reflection layer.
2 . The method for fabricating a selective emitter solar cell according to claim 1 , wherein the forming of a selective emitter solar cell base having a buried grid electrode comprises:
forming an emitter groove in a semiconductor substrate;
forming an emitter P-N junction near the emitter groove in the semiconductor substrate; and
forming a barrier layer, a conducting layer and a bond layer sequentially in the emitter groove, which form the buried grid electrode.
3 . The method for fabricating a selective emitter solar cell according to claim 2 , wherein the emitter groove has a width of 10-50 μm and a depth of 10-50 μm.
4 . The method for fabricating a selective emitter solar cell according to claim 1 , wherein the bus-bar has a width of 3000-5000 μm.
5 . The method for fabricating a selective emitter solar cell according to claim 2 , wherein the semiconductor substrate surface has a sheet resistance larger than 100 Ω/□.
6 . The method for fabricating a selective emitter solar cell according to claim 2 , wherein the emitter groove surface has a sheet resistance less than 30 Ω/□.
7 . The method for fabricating a selective emitter solar cell according to claim 2 , wherein the material of the barrier layer is nickel, the material of the conducting layer is copper, and the material of the bond layer is silver.
8 . The method for fabricating a selective emitter solar cell according to claim 2 , wherein the barrier layer has a thickness of 2˜20 μm, the conducting layer has a thickness of 5˜50 μm, the bond layer has a thickness of 5˜50 μm.
9 . The method for fabricating a selective emitter solar cell according to claim 1 , wherein the material of the bus-bar is silver.
10 . The method for fabricating a selective emitter solar cell according to claim 1 , wherein the bus-bar and the buried grid electrode are arranged perpendicularly to each other.
11 . The method for fabricating a selective emitter solar cell according to claim 10 , wherein the buried grid electrodes are arranged in parallel to each other with the same distance therebetween.
12 . The method for fabricating a selective emitter solar cell according to claim 10 , wherein the bus-bars are arranged in parallel to each other with the same distance therebetween.
13 . The method for fabricating a selective emitter solar cell according to claim 2 , wherein the forming of the selective emitter solar cell base comprises forming a sub-buried grid electrode.
14 . The method for fabricating a selective emitter solar cell according to claim 13 , wherein the sub-buried grid electrode and the buried grid electrode intersect perpendicularly in the same plane, and the sub-buried grid electrode lies right underneath the bus-bar and in parallel to the bus-bar.
15 . The method for fabricating a selective emitter solar cell according to claim 13 , wherein the solar cell base is co-fired so that the bus-bar is connected with the buried grid electrode in the traversing direction underneath through the anti-reflection layer.
16 . A selective emitter solar cell, comprising:
a selective emitter solar cell base having a buried grid electrode;
an anti-reflection layer formed on the emitter surface of the solar cell base; and
a bus-bar formed on the anti-reflection layer, which is connected with the buried grid electrode in the traversing direction underneath through the anti-reflection layer.
17 . The selective emitter solar cell according to claim 16 , wherein the selective emitter solar cell base having a buried grid electrode comprises:
a semiconductor substrate;
an emitter groove formed in the semiconductor substrate;
an emitter P-N junction formed near the emitter groove in the semiconductor substrate; and
a barrier layer, a conducting layer and a bond layer formed sequentially in the emitter groove.
18 . The selective emitter solar cell according to claim 17 , wherein the emitter groove has a width of 10˜50 μm and a depth of 10˜50 μm.
19 . The selective emitter solar cell according to claim 16 , wherein the bus-bar has a width of 3000˜5000 μm.
20 . The selective emitter solar cell according to claim 17 , wherein the semiconductor substrate surface has a sheet resistance larger than 100 Ω/□.
21 . The selective emitter solar cell according to claim 17 , wherein the emitter groove surface has a sheet resistance less than 30 Ω/□.
22 . The selective emitter solar cell according to claim 17 , wherein the material of the barrier layer is nickel, the material of the conducting layer is copper, and the material of the bond layer is silver.
23 . The selective emitter solar cell according to claim 17 , wherein the barrier layer has a thickness of 2˜20 μm, the conducting layer has a thickness of 5˜50 μm, the bond layer has a thickness of 5˜50 μm.
24 . The selective emitter solar cell according to claim 16 , wherein the material of the bus-bar is silver.
25 . The selective emitter solar cell according to claim 16 , wherein the bus-bar and the buried grid electrode are arranged perpendicularly to each other.
26 . The selective emitter solar cell according to claim 25 , wherein the buried grid electrodes are arranged in parallel to each other with the same distance therebetween.
27 . The selective emitter solar cell according to claim 25 , wherein the bus-bars are arranged in parallel to each other with the same distance therebetween.
28 . The selective emitter solar cell according to claim 17 , wherein a sub-buried grid electrode is formed in forming of the selective emitter solar cell base.
29 . The selective emitter solar cell according to claim 28 , wherein the sub-buried grid electrode and the buried grid electrode intersect perpendicularly in the same plane, and the sub-buried grid electrode lies right underneath the bus-bar and in parallel to the bus-bar.