Battery composite layer and TOPCon battery

Abstract

The utility model relates to the technical field of solar cells, in particular to a cell composite layer and a TOPCon cell. The composite layer covers at least part of the surface of the silicon substrate, the composite layer comprises metal electrodes and copper plating layers covering the surfaces of the metal electrodes, and the metal electrodes are uniformly distributed on at least part of the surface of the silicon substrate in a dotted manner; wherein the width of the copper plating layer is larger than that of the metal electrode; the copper plating layer is used for completely covering the metal electrode to form the copper-clad silver electrode structure, and the copper-clad silver electrode structure can replace part of the silver paste electrode structure, so that the usage amount of the silver paste in the TOPCon battery can be reduced to 2mg / cm < 2 >; in addition, the metal electrodes are uniformly distributed on at least one part of the surface of the silicon substrate in a dotted manner, so that the working efficiency of the TOPCon battery can be improved to 26.5% or above by using a copper-clad silver electrode structure.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a battery composite layer and a TOPCon battery. Background Art

[0002] Currently, N-type TOPCon (tunneling oxide passivation contact) technology has been widely used in the production of solar cells as the main means of passivation contact technology; among them, most of the paste used in N-type TOPCon cells is silver paste. In addition, with the rapid growth of photovoltaic production capacity, the demand for several materials required for solar cells may increase significantly. These materials include silver, aluminum, copper and even silicon, which makes photovoltaic manufacturing capacity affected by the supply of some scarce metals.

[0003] Although silver paste can be used on the back of the N-type TOPCon battery to ensure a higher bifacial rate, too much silver paste will increase the manufacturing cost of the battery. In addition, the working efficiency of the N-type TOPCom battery using silver paste is maintained at 20%, which is difficult to improve further. Summary of the invention

[0004] The present application provides a battery composite layer and a TOPCon battery to solve the following technical problem: how to reduce the amount of silver paste used in the TOPCon battery while improving the working efficiency of the TOPCon battery.

[0005] In a first aspect, the present application provides a battery composite layer, which covers at least a portion of the surface of a silicon substrate, and the composite layer includes a metal electrode and a copper coating covering the surface of the metal electrode, and the metal electrode is evenly distributed in a dot-like manner on at least a portion of the surface of the silicon substrate; wherein the width of the copper coating is greater than the width of the metal electrode.

[0006] Optionally, a width ratio between the copper plating layer and the metal electrode is 1.1 to 1.4.

[0007] Optionally, the copper plating layer has a width of 1 mm to 5 mm.

[0008] Optionally, the copper plating layer has a thickness of 0.2 mm to 0.5 mm.

[0009] Optionally, the composite layer further includes at least one silicon carbide anti-reflection layer and at least one aluminum oxide passivation layer, and the metal electrode is disposed through the silicon carbide anti-reflection layer and the aluminum oxide passivation layer.

[0010] Optionally, the composite layer also includes a P-type emitter, a tunneling oxide layer and a doped polysilicon layer; the P-type emitter is arranged on the front side of the silicon substrate, the aluminum oxide passivation layer is arranged on the front side of the P-type emitter, and the silicon carbide anti-reflection layer is arranged on the front side of the aluminum oxide passivation layer; the tunneling oxide layer is arranged on the back side of the silicon substrate, the doped polysilicon layer is arranged on the back side of the tunneling oxide layer, the aluminum oxide passivation layer is arranged on the back side of the doped polysilicon layer, and the silicon carbide anti-reflection layer is arranged on the back side of the aluminum oxide passivation layer.

[0011] Optionally, the metal electrode is arranged to penetrate the silicon carbide anti-reflection layer and the aluminum oxide passivation layer, and one end of the metal electrode is connected to the P-type emitter or the doped polysilicon layer.

[0012] Optionally, one end of the metal electrode is inserted into the doped polysilicon layer by means of ohmic contact.

[0013] In a second aspect, the present application provides a TOPCon battery, wherein the TOPCon battery comprises the composite layer described in the first aspect.

[0014] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0015] The present application provides a battery composite layer, the composite layer covers at least a portion of the surface of the silicon substrate, the composite layer includes a metal electrode and a copper coating covering the surface of the metal electrode, the metal electrode is evenly distributed on at least a portion of the surface of the silicon substrate in a dot-like manner; wherein the width of the copper coating is greater than the width of the metal electrode. The width of the copper coating can be greater than the width of the metal electrode, which can cause the copper coating to completely cover the metal electrode to form a copper-clad silver electrode structure, and the formed copper-clad silver structure can replace part of the silver paste electrode structure, which can reduce the coverage area of ​​the silver paste material on the surface of the silicon substrate, thereby reducing the amount of silver paste used in the TOPCon battery; in addition, the metal electrode is evenly distributed on at least a portion of the surface of the silicon substrate in a dot-like manner, which can cause the copper-clad silver electrode structure to first derive current through the contact between silver and the silicon substrate and then collect current through copper, thereby using the copper-clad silver electrode structure to improve the working efficiency of the TOPCon battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0018] Figure 1 A schematic diagram of a battery composite layer structure provided in an embodiment of the present application;

[0019] Figure 2 A schematic diagram of a TOPCon battery structure provided in an embodiment of the present application;

[0020] Among them, 1-silicon substrate, 2-metal electrode, 3-copper plating layer, 4-silicon carbide anti-reflection layer, 5-aluminum oxide passivation layer, 6-P-type emitter, 7-tunneling oxide layer, and 8-doped polysilicon layer. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] It should be noted that all directional indications such as up, down, left, right, front, back, etc. in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection, a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] Figure 1 A schematic diagram of a battery composite layer structure provided in an embodiment of the present application is exemplarily shown;

[0025] like Figure 1As shown, an embodiment of the present application provides a battery composite layer, the composite layer covers at least a portion of the surface of a silicon substrate 1, the composite layer includes a metal electrode 2 and a copper plating layer 3 covering the surface of the metal electrode 2, the metal electrode 2 is evenly distributed in a dot shape on at least a portion of the surface of the silicon substrate 1; wherein the width of the copper plating layer 3 is greater than the width of the metal electrode 2;

[0026] It should be noted that the metal electrode 2 is formed by brushing silver paste onto the surface of the silicon nitride anti-reflection layer of the silicon substrate 1 using screen printing. Therefore, by covering the surface of the metal electrode 2 with a copper plating layer 3, the screen printing method can be improved in a targeted manner to reduce the amount of silver paste in the area covered by the copper plating layer 3, thereby reducing the amount of silver paste used in the TOPCon battery.

[0027] In some optional embodiments, the width ratio of the copper plating layer 3 to the metal electrode 2 is 1.1 to 1.4;

[0028] In these embodiments, the width ratio of the copper plating layer 3 and the metal electrode 2 can be 1.1 to 1.4, which can enable the copper plating layer 3 to effectively cover the metal electrode 2 to form a copper-clad silver electrode structure. On the one hand, the copper plating layer 3 in the copper-clad silver electrode structure effectively reduces the coverage area of ​​the silver paste material on the surface of the silicon substrate 1, thereby reducing the amount of silver paste used in the TOPCon battery. On the other hand, the copper-clad silver electrode structure can be used to first conduct current through the contact between silver and the silicon substrate 1 and then collect the current through copper, thereby using the copper-clad silver electrode structure to improve the working efficiency of the TOPCon battery.

[0029] The width ratio of the copper plating layer 3 to the metal electrode 2 may be 1.1, 1.2, 1.3 or 1.4.

[0030] In some optional embodiments, the width of the copper plating layer 3 is 1 mm to 5 mm;

[0031] In these embodiments, the width of the copper plating layer 3 can be 1 mm to 5 mm, which can further enable the copper plating layer 3 to effectively cover the metal electrode 2 to form a copper-clad silver electrode structure of sufficient thickness. The copper-clad silver electrode structure of sufficient thickness can further reduce the amount of silver paste used in the TOPCon battery, and the copper-clad silver electrode structure can be further used to improve the working efficiency of the TOPCon battery.

[0032] The width of the copper plating layer 3 may be 1 mm, 2 mm, 3 mm, 4 mm or 5 mm.

[0033] In some optional embodiments, the copper plating layer 3 has a thickness of 0.2 mm to 0.5 mm;

[0034] In these embodiments, the thickness of the copper plating layer 3 can be 0.2 mm to 0.5 mm, which can ensure that the copper plating layer 3 has a sufficient thickness. The copper plating layer 3 of sufficient thickness can form a copper-clad silver electrode structure of sufficient thickness with the metal electrode 2, which can further improve the efficiency of silver in the copper-clad silver electrode structure in contact with the silicon substrate 1 to extract current and the efficiency of the copper plating layer 3 in collecting current, thereby effectively improving the working efficiency of the TOPCon battery.

[0035] The thickness of the copper plating layer 3 can be 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.

[0036] In some optional embodiments, the composite layer further includes at least one silicon carbide anti-reflection layer 4 and at least one aluminum oxide passivation layer 5, and the metal electrode 2 is disposed through the silicon carbide anti-reflection layer 4 and the aluminum oxide passivation layer 5;

[0037] In these embodiments, the composite layer may further include at least one silicon carbide anti-reflection layer 4 and at least one aluminum oxide passivation layer 5 , which may enable the composite layer to form a complete TOPCon cell matrix on the surface of the silicon substrate 1 .

[0038] In some optional embodiments, the composite layer further includes a P-type emitter 6, a tunneling oxide layer 7 and a doped polysilicon layer 8; the P-type emitter 6 is arranged on the front side of the silicon substrate 1, the aluminum oxide passivation layer 5 is arranged on the front side of the P-type emitter 6, and the silicon carbide anti-reflection layer 4 is arranged on the front side of the aluminum oxide passivation layer 5; the tunneling oxide layer 7 is arranged on the back side of the silicon substrate 1, the doped polysilicon layer 8 is arranged on the back side of the tunneling oxide layer, the aluminum oxide passivation layer 5 is arranged on the back side of the doped polysilicon layer 8, and the silicon carbide anti-reflection layer 4 is arranged on the back side of the aluminum oxide passivation layer 5;

[0039] In these embodiments, the composite layer may also include a P-type emitter 6, a tunneling oxide layer 7 and a doped polysilicon layer 8, which may cooperate with the copper-clad silver electrode structure formed by the metal electrode 2 and the copper plating layer 3 to form the base structure of the TOPCon battery.

[0040] In some optional embodiments, the metal electrode 2 is disposed through the silicon carbide anti-reflection layer 4 and the aluminum oxide passivation layer 5, and one end of the metal electrode 2 is connected to the P-type emitter 6 or the doped polysilicon layer 8;

[0041] In these embodiments, the metal electrode 2 can penetrate the silicon carbide anti-reflection layer 4 and the aluminum oxide passivation layer 5, and one end of the metal electrode 2 can be connected to the P-type emitter 6 or the doped polysilicon layer 8, which can further improve the efficiency of the silver in the copper-clad silver electrode structure to conduct current in contact with the silicon substrate 1 and the efficiency of the copper plating layer 3 to collect current, thereby effectively improving the working efficiency of the TOPCon battery.

[0042] In some optional embodiments, one end of the metal electrode 2 is inserted into the doped polysilicon layer 8 by means of ohmic contact.

[0043] In these embodiments, one end of the metal electrode 2 is inserted into the doped polysilicon layer 8 by means of ohmic contact, which can promote a firm bond between the metal electrode 2 and the doped polysilicon layer 8. The firmly bonded metal electrode 2 can further improve the efficiency of the silver contact doped polysilicon layer 8 in the copper-clad silver electrode structure in extracting current and the efficiency of the copper plating layer 3 in collecting current, thereby effectively improving the working efficiency of the TOPCon battery.

[0044] Figure 2 A schematic diagram of a TOPCon battery structure provided in an embodiment of the present application is exemplarily shown;

[0045] Based on a general inventive concept, such as Figure 2 As shown, an embodiment of the present application provides a TOPCon battery, and the TOPCon battery includes the composite layer.

[0046] The TOPCon battery is realized based on the above-mentioned composite layer. The specific structure of the composite layer can refer to the above-mentioned embodiment. Since the TOPCon battery adopts part or all of the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0047] It should be noted that in order to prepare the TOPCon battery, the preparation steps may include:

[0048] S1. Boron diffusion is performed on the front side of the silicon substrate 1 to obtain a first silicon substrate containing a P+ doped layer;

[0049] S2. performing back etching on the back side of the first silicon substrate, and then performing polishing to obtain a pretreated silicon substrate;

[0050] S3. Deposition of a tunneling oxide layer 7 and a polysilicon layer is performed on the surface of the pretreated silicon substrate, followed by phosphorus doping to obtain a second silicon substrate containing a tunneling oxide layer 7 and a doped polysilicon layer 8;

[0051] S4. removing the front surface coating of the second silicon substrate, and then depositing an aluminum oxide passivation layer 5 and a silicon carbide anti-reflection layer 4 to obtain a third silicon substrate containing an aluminum oxide passivation layer 5 and a silicon carbide anti-reflection layer 4;

[0052] S5. Screen printing is performed on the front or back of the third silicon substrate, and then sintering is performed to obtain a fourth silicon substrate containing a metal electrode 2;

[0053] S6. electroplating the fourth silicon substrate using a copper salt solution so that the surface of the metal electrode 2 is covered with a copper plating layer 3 to obtain a TOPCon battery;

[0054] Wherein, the electroplating temperature is 30°C to 80°C, and the electroplating time is 10min to 30min; and / or,

[0055] The copper salt solution comprises at least one of the following:

[0056] Copper sulfate and / or copper chloride.

[0057] It should be noted that the difference between the first silicon substrate, the second silicon substrate, the third silicon substrate and the fourth silicon substrate is only the layered structure of the silicon substrate surface, and the silicon substrate in the first silicon substrate, the second silicon substrate, the third silicon substrate and the fourth silicon substrate can all use n-type single crystal silicon substrates or n-type single crystal silicon substrates.

[0058] The present application is further described below in conjunction with specific examples. The experimental methods in the following examples that do not specify specific conditions are usually measured according to industry standards; if there are no corresponding industry standards, they are carried out according to common international standards, conventional conditions, or conditions recommended by the manufacturer.

[0059] Example 1

[0060] like Figure 1 As shown, a battery composite layer covers a portion of the surface of a silicon substrate 1. The composite layer includes a metal electrode 2 and a copper plating layer 3 covering the surface of the metal electrode 2. The metal electrode 2 is evenly distributed on the surface of the silicon substrate 1 in a dot shape; wherein the width of the copper plating layer 3 is greater than the width of the metal electrode 2.

[0061] The width ratio of the copper plating layer 3 to the metal electrode 2 is 1.2.

[0062] The width of the copper plating layer 3 is 4 mm.

[0063] The thickness of the copper plating layer 3 is 0.3 mm.

[0064] The composite layer further includes two silicon carbide anti-reflection layers 4 and two aluminum oxide passivation layers 5 , and the metal electrode 2 is arranged to penetrate the silicon carbide anti-reflection layers 4 and the aluminum oxide passivation layers 5 .

[0065] The composite layer also includes a P-type emitter 6, a tunneling oxide layer 7 and a doped polysilicon layer 8; the P-type emitter 6 is arranged on the front side of the silicon substrate 1, the aluminum oxide passivation layer 5 is arranged on the front side of the P-type emitter 6, and the silicon carbide anti-reflection layer 4 is arranged on the front side of the aluminum oxide passivation layer 5; the tunneling oxide layer 7 is arranged on the back side of the silicon substrate 1, the doped polysilicon layer 8 is arranged on the back side of the tunneling oxide layer, the aluminum oxide passivation layer 5 is arranged on the back side of the doped polysilicon layer 8, and the silicon carbide anti-reflection layer 4 is arranged on the back side of the aluminum oxide passivation layer 5.

[0066] The metal electrode 2 is disposed through the silicon carbide anti-reflection layer 4 and the aluminum oxide passivation layer 5 , and one end of the metal electrode 2 is connected to the P-type emitter 6 or the doped polysilicon layer 8 .

[0067] One end of the metal electrode 2 is inserted into the doped polysilicon layer 8 in an ohmic contact manner.

[0068] like Figure 2 As shown, a TOPCon battery comprises the composite layer.

[0069] Example 2

[0070] Based on the contents disclosed in Example 1, the following operations are further performed:

[0071] The width ratio of the copper plating layer 3 to the metal electrode 2 is 1.1.

[0072] The width of the copper plating layer 3 is 1 mm.

[0073] The thickness of the copper plating layer 3 is 0.2 mm.

[0074] Example 3

[0075] Based on the contents disclosed in Example 1, the following operations are further performed:

[0076] The width ratio of the copper plating layer 3 to the metal electrode 2 is 1.4.

[0077] The width of the copper plating layer 3 is 5 mm.

[0078] The thickness of the copper plating layer 3 is 0.5 mm.

[0079] Comparative Example 1

[0080] Based on the contents disclosed in Example 1, the following operations are further performed:

[0081] No copper plating layer 3 is used, and no electroplating is used in the manufacturing method.

[0082] Comparative Example 2

[0083] Based on the contents disclosed in Example 1, the following operations are further performed:

[0084] No copper plating layer 3 is used, and no electroplating is used in the manufacturing method.

[0085] The width ratio of the copper plating layer 3 to the metal electrode 2 is 1.0.

[0086] The width of the copper plating layer 3 is 0.9 mm.

[0087] The thickness of the copper plating layer 3 is 0.1 mm.

[0088] Comparative Example 3

[0089] Based on the contents disclosed in Example 1, the following operations are further performed:

[0090] The width ratio of the copper plating layer 3 to the metal electrode 2 is 2.0.

[0091] The width of the copper plating layer 3 is 5 mm.

[0092] The thickness of the copper plating layer 3 is 0.5 mm.

[0093] Related experiments and effect data:

[0094] The working efficiency test of the TOPCon batteries obtained in each embodiment and comparative example and the amount of silver paste used in the preparation process were statistically analyzed, and the results are shown in Table 1.

[0095] TOPCon battery working efficiency test method: After the battery is manufactured, it is tested by a solar cell tester to obtain parameters such as conversion efficiency, open circuit voltage, short circuit current, and fill factor.

[0096] Preparation process of TOPCon battery Silver paste usage test method: During the screen printing process of silicon wafers, weigh the weight of the silicon wafer itself on an analytical balance before printing, and then weigh it on an analytical balance after printing but before sintering. The difference between the two is the silver paste usage.

[0097] Table 1 TOPCon battery working efficiency of each embodiment and comparative example and the amount of silver paste used in the preparation process

[0098]

[0099] As can be seen from Table 1, a battery composite layer provided in an embodiment of the present application uses a copper plating layer 3 to completely cover the metal electrode 2 to form a copper-clad silver electrode structure, and the formed copper-clad silver structure can replace part of the silver paste electrode structure, which can reduce the coverage area of ​​the silver paste material on the surface of the silicon substrate 1, thereby reducing the amount of silver paste used in the TOPCon battery to 2 mg / cm 2 In addition, the metal electrodes 2 are evenly distributed in a dot shape on at least a portion of the surface of the silicon substrate 1, which can cause the copper-clad silver electrode structure to first conduct current through the contact between silver and the silicon substrate and then collect the current through copper, thereby using the copper-clad silver electrode structure to increase the working efficiency of the TOPCon battery to more than 26.5%.

[0100] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown in the present application, but will conform to the widest scope consistent with the principles and novel features applied for by the present application.

Claims

1. A battery composite layer, the composite layer covering at least part of the surface of a silicon substrate (1), characterized in that: The composite layer comprises a metal electrode (2) and a copper plating layer (3) covering the surface of the metal electrode (2); the metal electrode (2) is evenly distributed in a dotted manner on at least a portion of the surface of the silicon substrate (1); wherein the width of the copper plating layer (3) is greater than the width of the metal electrode (2).

2. The composite layer according to claim 1, characterized in that The width ratio of the copper plating layer (3) to the metal electrode (2) is 1.1 to 1.

4.

3. The composite layer according to claim 1 or 2, characterized in that: The width of the copper plating layer (3) is 1 mm to 5 mm.

4. The composite layer according to claim 1 or 2, characterized in that: The thickness of the copper plating layer (3) is 0.2 mm to 0.5 mm.

5. The composite layer according to claim 1, characterized in that The composite layer further comprises at least one silicon carbide anti-reflection layer (4) and at least one aluminum oxide passivation layer (5), and the metal electrode (2) is arranged to penetrate the silicon carbide anti-reflection layer (4) and the aluminum oxide passivation layer (5).

6. The composite layer according to claim 5, characterized in that The composite layer further comprises a P-type emitter (6), a tunneling oxide layer (7) and a doped polysilicon layer (8); the P-type emitter (6) is arranged on the front side of the silicon substrate (1), the aluminum oxide passivation layer (5) is arranged on the front side of the P-type emitter (6), and the silicon carbide anti-reflection layer (4) is arranged on the front side of the aluminum oxide passivation layer (5); the tunneling oxide layer (7) is arranged on the back side of the silicon substrate (1), the doped polysilicon layer (8) is arranged on the back side of the tunneling oxide layer, the aluminum oxide passivation layer (5) is arranged on the back side of the doped polysilicon layer (8), and the silicon carbide anti-reflection layer (4) is arranged on the back side of the aluminum oxide passivation layer (5).

7. The composite layer according to claim 6, characterized in that The metal electrode (2) is arranged to penetrate the silicon carbide anti-reflection layer (4) and the aluminum oxide passivation layer (5), and one end of the metal electrode (2) is connected to the P-type emitter (6) or the doped polysilicon layer (8).

8. The composite layer according to claim 7, characterized in that One end of the metal electrode (2) is inserted into the doped polysilicon layer (8) in an ohmic contact manner.

9. A TOPCon battery, characterized in that: The TOPCon cell comprises the composite layer according to any one of claims 1 to 7.

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