Low-consumption silver paste solar cell

Abstract

The invention provides a low-consumption silver paste solar cell which comprises a cell substrate, a first conductive layer, a second conductive layer and a welding wire which are electrically connected in sequence are arranged on the cell substrate, and the first conductive layer is a grid line and is used for collecting and transmitting current; the used paste has two forms, one form is that the whole paste comprises one or more metal alloys of aluminum, copper, nickel, tin and lead, the other form is that part of the paste comprises one or more metal alloys of aluminum, copper, nickel, tin and lead, and the rest of the paste is silver paste; the second conductive layer is blocky, is made of silver paste and is used for transmitting current and enhancing the bonding strength of the welding wire and the battery; and the welding wire is used for leading out current. The first conductive layer and the second conductive layer are made of paste with different components, so that the use amount of silver paste is reduced under the condition that the performance of the solar cell is kept stable, and the cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of solar cells, in particular to a low-consumption silver paste solar cell sheet. Background Art

[0002] Silver paste accounts for more than 20% of the material cost of solar cells, resulting in high costs and insufficient competitiveness. Therefore, Chinese patent CN113410316A discloses a low-silver consumption solar cell and a manufacturing method thereof, which uses fine copper grid lines on the back to replace the fine silver paste grids on the back, effectively reducing the amount of silver paste used.

[0003] However, in the above-mentioned patent, the amount of silver paste used in the main grid is still relatively high. Therefore, how to further reduce the amount of silver paste while ensuring that the performance of the battery cell remains stable has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] In order to solve the technical problems in the background technology, the present invention discloses a low-consumption silver paste solar cell.

[0005] The present invention provides a low-consumption silver paste solar cell sheet, comprising a battery substrate, on which a first conductive layer, a second conductive layer and a welding wire which are electrically connected in sequence are arranged:

[0006] The first conductive layer is a grid line, which is used to collect and transmit current; the paste used therein has two forms, one of which is a paste that contains one or several metal alloys among aluminum, copper, nickel, tin, and lead, and the other is a paste that contains one or several metal alloys among aluminum, copper, nickel, tin, and lead, and the rest of the paste is silver paste;

[0007] The second conductive layer is in block shape and is made of silver paste, which is used for current transmission and enhances the bonding strength between the welding wire and the battery.

[0008] The welding wire is used to conduct the electric current.

[0009] The first conductive layer and the second conductive layer use pastes with different compositions, which reduces the amount of silver paste used while ensuring that the performance of the solar cell remains stable, thereby reducing costs.

[0010] The grid line has two structures. The first structure is: the grid line is composed of stacked lower grid and upper grid. The lower grid is located at the bottom layer and connected to the battery substrate. The paste used for the lower grid is one or more metal alloys including aluminum, copper, nickel, tin, and lead. The paste used for the upper grid is silver paste. This structure has the following three technical effects: 1. It ensures good ohmic contact between the first conductive layer and the battery body; 2. It can obtain a higher aspect ratio of the first conductive layer; 3. The lower grid does not contain silver paste, which can reduce the amount of silver paste.

[0011] The second type of grid line structure is a single-layer structure, and the paste used is one or more metal alloys including aluminum, copper, nickel, tin, and lead; this structure not only has good electrical conductivity, but also can reduce the amount of silver paste used. The single-layer structure grid line has the following two forms: one is that the grid line is composed of a main grid and a fine grid, and the second conductive layer is evenly and spacedly distributed at the upper end of the connection between the main grid and the fine grid; the other is that the grid line is only composed of a fine grid, and the second conductive layer is evenly and spacedly distributed at the upper end of the fine grid.

[0012] The gate line is composed of a main gate and a fine gate, and a groove is provided at the connection between the fine gate and the main gate; the second conductive layer is clamped in the groove. The provision of the groove not only realizes the positioning of the second conductive layer, but also increases the contact area between the second conductive layer and the first conductive layer, and the ohmic contact performance is better.

[0013] The groove has the following two structures, one of which is: the depth of the groove is less than the height of the grid line; the second conductive layer protrudes from the grid line in the direction away from the battery base. The second is: the groove runs through the grid line, dividing the fine grid and the main grid into multiple sections; the second conductive layer is covered with the groove and is flush with the top of the grid line; the welding wire contacts both the first conductive layer and the second conductive layer, replacing the structure in which the first conductive layer, the second conductive layer and the welding wire are electrically connected in sequence. The function of the second structure is to increase the welding bonding strength between the welding wire and the conductive layer; the reason is: in order to reduce optical loss, the width of the first conductive layer will be made narrower, and in order to reduce the amount of silver paste, the first conductive layer uses a paste that does not contain silver, and the solderability of the first conductive layer will be relatively poor. Therefore, this structure can increase solderability, and the second conductive layer uses a paste containing silver, which can not only ensure the good current transmission performance of the second conductive layer, but also ensure its good solderability.

[0014] The gate line is only composed of thin gates; the thin gates are provided with grooves; the second conductive layer is clamped in the grooves. The provision of the grooves not only realizes the positioning of the second conductive layer, but also increases the contact area between the second conductive layer and the first conductive layer, and the ohmic contact performance is better.

[0015] The groove has the following two structures, one of which is: the depth of the groove is less than the height of the grid line; the second conductive layer protrudes from the grid line in the direction away from the battery substrate. The second is: the groove runs through the grid line, dividing the fine grid into multiple sections; the second conductive layer is covered with the groove and is flush with the top of the grid line; the welding wire contacts both the first conductive layer and the second conductive layer, replacing the structure in which the first conductive layer, the second conductive layer and the welding wire are electrically connected in sequence. The function of the second structure is to increase the welding strength between the welding wire and the conductive layer; the reason is: in order to reduce optical loss, the width of the first conductive layer will be made narrower, and in order to reduce the amount of silver paste, the first conductive layer uses a paste that does not contain silver, and the solderability of the first conductive layer will be relatively poor. Therefore, this structure can increase solderability, and the second conductive layer uses a paste containing silver, which can not only ensure the good current transmission performance of the second conductive layer, but also ensure its good solderability.

[0016] The beneficial effect of the present invention is that the first conductive layer and the second conductive layer use slurries with different components, which reduces the amount of silver paste used while ensuring that the performance of the solar cell remains stable, thereby reducing the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0018] Figure 1 It is a schematic diagram of the structure of the present invention;

[0019] Figure 2 is a front view of the present invention, wherein the grid line is composed of an upper grid and a lower grid;

[0020] Figure 3 is a front view of the present invention, wherein the gate line is a single-layer structure;

[0021] Figure 4 is a front view of the present invention, wherein the first conductive layer is provided with a groove;

[0022] Figure 5 is a front view of the present invention, wherein the first conductive layer is provided with grooves of another structure;

[0023] Figure 6 is a right view of the present invention; wherein the first conductive layer is not provided with a groove, or is provided with Figure 4 The groove in the

[0024] Figure 7 is a right view of the present invention; wherein the first conductive layer is provided with Figure 5 Grooves in

[0025] Figure 8 is a top view of the present invention;

[0026] In the figure: 1, battery substrate; 2, first conductive layer; 3, second conductive layer; 4, welding wire; 21, main grid; 22, fine grid; 23, groove; 24, lower grid; 25, upper grid. DETAILED DESCRIPTION

[0027] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0028] Embodiment 1:

[0029] like Figure 1 , Figure 3 and Figure 6As shown, the present invention discloses a low-silver paste solar cell sheet, comprising a cell substrate 1, on which a first conductive layer 2, a second conductive layer and a welding wire 4 which are electrically connected in sequence in a stacked manner are arranged.

[0030] The battery body except the electrodes is the battery substrate 1, and any type of battery such as PERC, TOPcon, heterojunction, etc. can be used.

[0031] The first conductive layer 2 is a grid line for collecting and transmitting current; it is composed of a main grid 21 and a fine grid 22. The first conductive layer 2 is an integrated single-layer structure, and the slurry used contains one or more metal alloys of aluminum, copper, nickel, tin, and lead. The first conductive layer 2 is sintered into one with the battery substrate 1, and its function is to collect the photogenerated carriers generated by the battery substrate 1 when exposed to light and transmit them to the second conductive layer 3.

[0032] The second conductive layer 3 is block-shaped and evenly and spacedly distributed at the upper end of the connection between the main grid 21 and the fine grid 22, and is used for current transmission to enhance the bonding strength between the welding wire 4 and the battery.

[0033] The welding wire 4 is located directly above the main grid 21 and is parallel to the main grid 21. The welding wire 4 transmits the photovoltaic current of the battery. The welding wire 4 can be round or flat, and is a copper wire plated with solder. The copper wire has good electrical conductivity. The copper wire is plated with solder to improve its solderability. The solder can be tin, tin-lead, tin-lead-indium, tin-lead-silver, tin-bismuth, tin-lead-bismuth, tin-bismuth-silver, etc.

[0034] The first conductive layer 2 and the second conductive layer 3 use slurries with different compositions, which reduces the amount of silver paste used while ensuring that the performance of the solar cell remains stable, thereby reducing costs. In addition, the second conductive layer 3 is located directly above the first conductive layer 2. The first conductive layer 2 is continuous, and the second conductive layer 3 is distributed in sections. It is only necessary to arrange a few points at intervals directly below the welding wire 4 to ensure a good bonding strength between the welding wire 4 and the battery, thereby further reducing the amount of silver-containing slurry used and achieving the purpose of reducing the cost of silver slurry.

[0035] Embodiment 2:

[0036] Compared with the first embodiment, the difference is: Figure 2 As shown, the grid line is composed of stacked lower grid 24 and upper grid 25, the lower grid 24 is located at the lower layer and connected to the battery substrate 1; the paste used for the lower grid 24 is one or more metal alloys including aluminum, copper, nickel, tin, and lead; the paste used for the upper grid 25 is silver paste. This structure has the following three technical effects: 1. It ensures good ohmic contact between the first conductive layer 2 and the battery body; 2. It can obtain a higher aspect ratio of the first conductive layer 2; 3. The lower grid 24 does not contain silver paste, which can reduce the amount of silver paste.

[0037] Embodiment three:

[0038] Compared with the first embodiment, the difference is: Figure 4 As shown, a groove 23 is provided at the connection between the fine gate 22 and the main gate 21; the second conductive layer 3 is clamped in the groove 23. The provision of the groove 23 not only realizes the positioning of the second conductive layer 3, but also increases the contact area between the second conductive layer 3 and the first conductive layer 2, and the ohmic contact performance is better.

[0039] The depth of the groove 23 is smaller than the height of the gate line; the second conductive layer 3 protrudes from the gate line in a direction away from the battery substrate 1 .

[0040] Embodiment 4:

[0041] Compared with the third embodiment, the difference is: Figure 5 As shown, the groove 23 runs through the grid line, dividing the fine grid 22 and the main grid 21 into multiple sections; the second conductive layer 3 is covered with the groove 23 and is flush with the top of the grid line; the welding wire 4 is in contact with both the first conductive layer 2 and the second conductive layer 3, replacing the structure in which the first conductive layer 2, the second conductive layer and the welding wire 4 are electrically connected in sequence. The welding wire 4 is in contact with the first conductive layer 2 through solder. The purpose of such a setting is to increase the welding bonding strength between the welding wire 4 and the conductive layer; the reason is: in order to reduce optical loss, the width of the first conductive layer 2 will be made relatively narrow, and in order to reduce the amount of silver paste, the first conductive layer 2 uses a paste that does not contain silver, and the solderability of the first conductive layer 2 will be relatively poor. Therefore, the use of this structure can increase solderability, and the second conductive layer 3 uses a silver-containing paste, which can be a silver paste, or a silver-containing alloy paste such as tin-silver, tin-lead-silver, tin-silver-copper, etc., which can not only ensure the good current transmission performance of the second conductive layer 3, but also ensure its good solderability.

[0042] Embodiment five:

[0043] Compared with the first embodiment, the difference is: Figure 6 , Figure 8 and Figure 3 As shown, the grid line is only composed of the thin grid 22, and the second conductive layer 3 is evenly and spacedly distributed on the upper end of the thin grid 22. The welding wire 4 is perpendicular to the thin grid 22.

[0044] Embodiment six:

[0045] Compared with the fifth embodiment, the difference is: Figure 2As shown, the grid line is composed of stacked lower grid 24 and upper grid 25, the lower grid 24 is located at the lower layer and connected to the battery substrate 1; the paste used for the lower grid 24 is one or more metal alloys including aluminum, copper, nickel, tin, and lead; the paste used for the upper grid 25 is silver paste. This structure has the following three technical effects: 1. It ensures good ohmic contact between the first conductive layer 2 and the battery body; 2. It can obtain a higher aspect ratio of the first conductive layer 2; 3. The lower grid 24 does not contain silver paste, which can reduce the amount of silver paste.

[0046] Embodiment seven:

[0047] Compared with the fifth embodiment, the difference is: Figure 4 As shown, the fine grid 22 is provided with a groove 23; the second conductive layer 3 is clamped in the groove 23. The provision of the groove 23 not only realizes the positioning of the second conductive layer 3, but also increases the contact area between the second conductive layer 3 and the first conductive layer 2, and the ohmic contact performance is better.

[0048] The depth of the groove 23 is smaller than the height of the gate line; the second conductive layer 3 protrudes from the gate line in a direction away from the battery substrate 1 .

[0049] Embodiment eight:

[0050] Compared with the seventh embodiment, the difference is: Figure 5 and Figure 7 As shown, the groove 23 penetrates the fine grid 22, dividing the fine grid 22 into multiple sections; the second conductive layer 3 is covered with the groove 23 and is flush with the top of the fine grid 22; the welding wire 4 is in contact with both the first conductive layer 2 and the second conductive layer 3, replacing the structure in which the first conductive layer 2, the second conductive layer and the welding wire 4 are electrically connected in sequence. The welding wire 4 is in contact with the first conductive layer 2 through the solder. The purpose of such a setting is to increase the welding bonding strength between the welding wire 4 and the conductive layer; the reason is: in order to reduce optical loss, the width of the first conductive layer 2 will be made narrower, and in order to reduce the amount of silver paste, the first conductive layer 2 uses a paste that does not contain silver, and the solderability of the first conductive layer 2 will be relatively poor. Therefore, the use of this structure can increase solderability, and the second conductive layer 3 uses a paste containing silver, which can not only ensure the good current transmission performance of the second conductive layer 3, but also ensure its good solderability.

[0051] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A low-consumption silver paste solar cell, comprising a cell substrate (1), characterized in that: The battery substrate (1) is provided with a first conductive layer (2), a second conductive layer (3) and a welding wire (4) which are electrically connected in sequence: The first conductive layer (2) is a grid line for collecting and transmitting current; the paste used therein has two forms, one of which is a paste that contains one or more metal alloys of aluminum, copper, nickel, tin, and lead, and the other is a paste that contains one or more metal alloys of aluminum, copper, nickel, tin, and lead, and the rest of the paste is silver paste; The second conductive layer (3) is in block shape and is made of silver paste, which is used for current transmission and enhances the bonding strength between the welding wire (4) and the battery; The welding wire (4) is used to conduct electric current.

2. A low-consumption silver paste solar cell according to claim 1, characterized in that: The grid line is composed of a stacked lower grid (24) and an upper grid (25), wherein the lower grid (24) is located at the lower layer and connected to the battery substrate (1); The paste used for the lower grid (24) is a metal alloy containing one or more of aluminum, copper, nickel, tin and lead; The paste used for the upper grid (25) is silver paste.

3. The low-consumption silver paste solar cell according to claim 1, characterized in that: The grid line is a single-layer structure, consisting of a main grid (21) and a fine grid (22); The slurry used for the gate line is a metal alloy containing one or more of aluminum, copper, nickel, tin and lead; The second conductive layer (3) is evenly and spacedly distributed on the upper end of the connection between the main grid (21) and the fine grid (22).

4. The low-consumption silver paste solar cell according to claim 3, characterized in that: A groove (23) is provided at the connection between the fine grid (22) and the main grid (21); The second conductive layer (3) is snapped into the groove (23).

5. The low-consumption silver paste solar cell according to claim 4, characterized in that: The depth of the groove (23) is less than the height of the grid line; The second conductive layer (3) has grid lines protruding in a direction away from the battery substrate (1).

6. The low-consumption silver paste solar cell according to claim 4, characterized in that: The groove (23) penetrates the gate line, dividing the fine gate (22) and the main gate (21) into multiple sections; The second conductive layer (3) covers the entire groove (23) and is flush with the top of the gate line; The welding wire (4) contacts both the first conductive layer (2) and the second conductive layer (3), replacing a structure in which the first conductive layer (2), the second conductive layer (3) and the welding wire (4) are electrically connected in sequence.

7. The low-consumption silver paste solar cell according to claim 1, characterized in that: The grid line is a single-layer structure, consisting only of fine grids (22); The slurry used for the gate line is a metal alloy containing one or more of aluminum, copper, nickel, tin and lead; The second conductive layer (3) is evenly and spacedly distributed on the upper end of the fine grid (22).

8. The low-consumption silver paste solar cell according to claim 7, characterized in that: The fine grid (22) is provided with a groove (23); The second conductive layer (3) is snapped into the groove (23).

9. The low-consumption silver paste solar cell according to claim 8, characterized in that: The depth of the groove (23) is less than the height of the grid line; the second conductive layer (3) protrudes from the grid line in a direction away from the battery substrate (1).

10. The low-consumption silver paste solar cell according to claim 8, characterized in that: The groove (23) penetrates the grid line, dividing the fine grid (22) into multiple sections; the second conductive layer (3) covers the groove (23) and is flush with the top of the grid line; the welding wire (4) contacts both the first conductive layer (2) and the second conductive layer (3), replacing the structure in which the first conductive layer (2), the second conductive layer (3) and the welding wire (4) are electrically connected in sequence.

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