Fabrication method of HJT negative-pitch series battery module, HJT negative-pitch series battery module

Abstract

This invention relates to semiconductor battery modules, specifically to a method for fabricating a HJT negative-pitch series battery module and the HJT negative-pitch series battery module itself. This invention addresses the shortcomings of traditional battery module fabrication, where a certain distance must be maintained between battery cells to avoid mutual shading, leading to a reduction in effective light-absorbing area and overall module efficiency. The HJT negative-pitch series battery module is fabricated by constructing a transition layer on a heterojunction battery substrate, then using a vacuum hot-pressing process to fix the front and back coated metal wires of multiple heterojunction battery substrates in one step to obtain a battery string. The coated metal wires are then cut to separate the battery strings into individual sheets, and combined with a negative-pitch series connection method to complete the fabrication of the HJT negative-pitch module. The negative-pitch series connection method reduces space loss, increases the effective light-absorbing area of ​​the battery module, and thus improves the overall efficiency of the battery module.

Description

Technical Field

[0001] This invention relates to semiconductor battery modules, specifically to a method for fabricating an HJT negative-pitch series battery module and the HJT negative-pitch series battery module. Background Technology

[0002] Heterojunction (HJT) solar cells, with their higher bifaciality, open-circuit voltage, and efficiency, are considered the next-generation mainstream technology. Metal electrodes are a key step in the fabrication of HJT solar cells. However, the high consumption and cost of the low-temperature silver paste used in current HJT solar cells significantly increase their manufacturing costs, hindering their marketization.

[0003] Chinese patent CN115832071A discloses a metallization scheme that does not require silver paste. This scheme solves the problem of current extraction by welding coated metal wires onto a transparent conductive oxide (TCO) film through a seed layer. However, it does not mention how to fabricate the battery module. In traditional battery module manufacturing, a certain distance needs to be left between the cells to avoid mutual shading, but this reduces the effective light-absorbing area and lowers the overall efficiency of the battery module. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of traditional battery module manufacturing, where a certain distance needs to be left between battery cells to avoid mutual shading, which leads to a reduction in effective light absorption area and a decrease in the overall efficiency of the battery module. The invention provides a method for preparing an HJT negative spacing series battery module and an HJT negative spacing series battery module.

[0005] To address the shortcomings of the existing technology, the present invention provides the following technical solution:

[0006] A method for fabricating an HJT negative-pitch series battery module, characterized by the following steps:

[0007] Step 1: Set a transition layer on both the front and back TCO films of the heterojunction solar cell substrate;

[0008] Step 2: On the front and back sides of the A heterojunction battery substrates that are arranged side by side and parallel to each other after being processed in Step 1, multiple parallel coated metal wires are set by hot pressing welding. Each coated metal wire contacts the transition layer of the A heterojunction battery substrates in sequence; A is a positive integer greater than 1.

[0009] Step 3: Cut off all the coated metal wires on the side adjacent to each heterojunction battery substrate that protrude 0-1mm from the edge of the heterojunction battery substrate.

[0010] Step 4: Remove the transition layer not covered by the coated metal wires by chemical etching to obtain the battery unit;

[0011] Step 5: Sorting the battery cells obtained in Step 4;

[0012] Step 6: Connect the battery cells obtained in step 5 in series using a negative-pitch series connection method;

[0013] Step 6.1: Set an overlapping area with a width of 0.1 to 1 mm on the front side of the previous battery cell near the edge of the next battery cell and on the back side of the next battery cell near the edge of the previous battery cell;

[0014] Step 6.2: Apply conductive material to the overlapping area and the surface of the plated metal wire in the overlapping area, and then press the two adjacent overlapping areas together so that the plated metal wires in the two overlapping areas are in contact.

[0015] Step 6.3: Weld the plated metal wires on the back of the first battery cell and the front of the Ath battery cell to the busbar to complete the fabrication of the HJT negative-pitch series battery module.

[0016] Furthermore, step 2 specifically includes:

[0017] Step 2.1: Arrange multiple coated metal wires in parallel and with both ends taut to complete the placement of the lower coated metal wires;

[0018] Step 2.2: Place A heterojunction battery substrates that have been processed in Step 1 and are parallel to each other on the lower layer of coated metal wires. The spacing between adjacent heterojunction battery substrates is 0-1mm. Make each coated metal wire contact the transition layer on the back of the A heterojunction battery substrates in sequence, and make both ends protrude 1-10mm from the first heterojunction battery substrate and the A heterojunction battery substrate, respectively.

[0019] Step 2.3: Above the A heterojunction battery substrates in Step 2.2, arrange multiple coated metal wires in parallel and with both ends taut. Make each coated metal wire contact the transition layer on the front side of the A heterojunction battery substrates in sequence, with both ends protruding 1-10mm from the first heterojunction battery substrate and the A heterojunction battery substrate respectively, thus completing the placement of the upper coated metal wires.

[0020] Step 2.4: Cover the entire structure obtained in Step 2.3 with a high-temperature resistant film, then draw a vacuum, and press multiple coated metal wires onto the front and back sides of the A heterojunction battery substrate by hot pressing. Then, melt the coating on the surface of the coated metal wires by heating to complete the hot pressing welding.

[0021] Further, step 2.4 specifically involves covering the entire structure obtained in step 2.3 with a high-temperature resistant film, then evacuating to 0.2–80 kPa, pressing multiple coated metal wires onto the front and back sides of the A heterojunction battery substrates at 100–300°C, and melting the coating on the surface of the coated metal wires at 130–250°C to complete the hot-press welding.

[0022] Further, in step 2, the coating on the surface of the coated metal wire contains one or more of tin, lead, bismuth, indium, and zinc, and the coating thickness is 1 to 5 μm;

[0023] The diameter of the coated metal wire is 0.05 to 0.2 μm, the spacing between adjacent parallel coated metal wires is 0.5 to 3.5 mm, and the outermost coated metal wire is 0.5 to 3.5 mm away from the edge of the heterojunction solar cell substrate.

[0024] Furthermore, in step 1, the transition layer is a single-layer or multi-layer structure with a thickness of 10–500 nm; the transition layer is prepared using one or more of copper, zinc, lead, aluminum, nickel, tin, and chromium; when the transition layer is a multi-layer structure, the materials of each layer can be the same or different.

[0025] Furthermore, in step 3, the severance is performed by mechanical cutting or laser cutting.

[0026] Furthermore, in step 6.2, the conductive material is a conductive adhesive or a conductive paste.

[0027] Meanwhile, the present invention also provides an HJT negative-pitch series battery module, which is prepared using the above-mentioned method for preparing an HJT negative-pitch series battery module, and its special feature is:

[0028] It includes A battery cells connected in series. Each battery cell includes a heterojunction battery substrate. The front and back sides of the heterojunction battery substrate are sequentially provided with a TCO film, a transition layer and a metal layer.

[0029] The transition layer includes multiple conductors arranged parallel to each other on the surface of the TCO film, and the metal layer includes multiple coated metal wires respectively disposed on the front side of the multiple first conductors, with the distance between the two ends of each coated metal wire and the edge of the heterojunction battery substrate being 0 to 0.1 mm.

[0030] An overlapping area with a width of 0.1 to 1 mm is provided on the front of the previous battery cell near the edge of the next battery cell and on the back of the next battery cell near the edge of the previous battery cell. Conductive material is provided in the overlapping area and on the surface of the plated metal wire of the overlapping area. Adjacent overlapping areas are pressed together.

[0031] The plated metal wires on the back of the first battery cell and the front of the Ath battery cell are respectively welded to the busbar to draw out the current.

[0032] Furthermore, the coating on the surface of the coated metal wire contains one or more of tin, lead, bismuth, indium, and zinc, and the coating thickness is 1 to 5 μm;

[0033] The diameter of the coated metal wire is 0.05 to 0.2 μm, the spacing between adjacent parallel coated metal wires is 0.5 to 2.5 mm, and the outermost coated metal wire is 0.5 to 3.5 mm away from the edge of the heterojunction solar cell substrate.

[0034] Furthermore, the transition layer is a single-layer or multi-layer structure with a thickness of 10–500 nm; the transition layer is prepared using one or more of copper, zinc, lead, aluminum, nickel, tin, and chromium; when the transition layer is a multi-layer structure, the materials of each layer can be the same or different.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] (1) The method for preparing the HJT negative spacing series battery module of the present invention involves constructing a transition layer on a heterojunction battery substrate, and then using a vacuum hot pressing process to fix the front and back coated metal wires of multiple heterojunction battery substrates in one go to obtain a battery string; then cutting the coated metal wires to make the battery string independent sheets, and then combining the negative spacing series method to complete the fabrication of the HJT negative spacing module; wherein the negative spacing series method can reduce space loss, increase the effective light absorption area of ​​the battery module, and thus improve the overall efficiency of the battery module.

[0037] (2) The method for preparing the HJT negative spacing series battery module of the present invention arranges multiple coated metal wires at the same time and uses a single hot-press welding to fix the coated metal wires on the front and back of multiple heterojunction battery substrates. Compared with conventional string welding process, it has higher welding efficiency, and since the coated metal wires are still in a stretched state during welding, the position of the coated metal wires is guaranteed to be accurate.

[0038] (3) In the preparation method of HJT negative spacing series battery module of the present invention, multiple coated metal wires are first set by hot pressing welding, and then the coated metal wires are cut to make the battery string independent, which facilitates the subsequent removal of the transition layer and sorting.

[0039] (4) In the preparation method of the HJT negative spacing series battery module of the present invention, the current is directly led out by the metal wire plated on the surface of the battery cell at both ends, without the need to use a busbar on the surface of the battery cell, thus reducing shading and processes. Attached Figure Description

[0040] Figure 1This is a flowchart of the preparation method of the HJT negative-pitch series battery module of the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of the upper and lower coated metal wires after hot-press welding is completed in step 2.4 of this embodiment of the invention.

[0042] Figure 3 This is a schematic diagram of the battery cell structure in step 4 of an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of step 6.2 of an embodiment of the present invention, in which the coated metal wires of the two overlapping areas are brought into contact (the coated metal wires on the back of the previous battery cell and the front of the next battery cell are not shown);

[0044] Figure 5 This is a schematic diagram of the HJT negative-pitch series battery module obtained in step 6.3 of an embodiment of the present invention.

[0045] The reference numerals in the attached figures are explained as follows: 1-Heterojunction solar cell substrate, 11-Previous solar cell, 12-Next solar cell; 2-Coated metal wire, 21-Lower coated metal wire, 22-Upper coated metal wire; 3-Transition layer; 4-Conductive material; 5-Busbar; 6-Overlapping area; 7-Edge of heterojunction solar cell substrate; 8-TCO film. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0047] Reference Figure 1 A method for fabricating an HJT negative-pitch series battery module includes the following steps:

[0048] Step 1: A transition layer 3 is set on the TCO film 8 on both the front and back sides of the heterojunction solar cell substrate 1;

[0049] The transition layer 3 is a single-layer or multi-layer structure with a thickness of 10–500 nm; the transition layer 3 is prepared using one or more of copper, zinc, lead, aluminum, nickel, tin, and chromium; when the transition layer 3 is a multi-layer structure, the materials of each layer can be the same or different.

[0050] The transition layer 3 is used to reduce the contact resistance between the coated metal wire 2 and the TCO film 8, and to provide welding sites for the coated metal wire 2. After subsequent heating, the coating on the surface of the coated metal wire 2 melts and forms an alloy with the transition layer 3, so that the coated metal wire 2 can be fixed on the battery surface while completing the coating electrical contact between the TCO film 8 and the metal wire.

[0051] Step 2: On the front and back sides of the A heterojunction battery substrates 1 that have been processed in Step 1 and are parallel to each other, multiple parallel coated metal wires 2 are set by hot pressing welding. Each coated metal wire 2 contacts the transition layer 3 of the A heterojunction battery substrates 1 in sequence; A is a positive integer greater than 1.

[0052] The coating on the surface of the coated metal wire 2 contains one or more of tin, lead, bismuth, indium, and zinc, and the coating thickness is 1 to 5 μm.

[0053] The diameter of the coated metal wire 2 is 0.05 to 0.2 μm, the spacing between adjacent parallel coated metal wires 2 is 0.5 to 3.5 mm, and the minimum distance between the coated metal wire 2 perpendicular to its extension direction and the edge 7 of the heterojunction battery substrate is 0.5 to 3.5 mm.

[0054] Step 2.1: Arrange multiple coated metal wires 2 in parallel and with both ends taut to complete the placement of the lower coated metal wires 21;

[0055] Step 2.2: Place A heterojunction battery substrates 1 that have been processed in Step 1 and are parallel to each other above the lower layer metal wire 21. The spacing between adjacent heterojunction battery substrates 1 is 0-1mm. Make each metal wire 2 contact the transition layer 3 on the back of the A heterojunction battery substrates 1 in sequence, and make both ends protrude 11-10mm from the first heterojunction battery substrate 1 and the A heterojunction battery substrate 1, respectively.

[0056] Step 2.3: On the A heterojunction battery substrates 1 of step 2.2, multiple coated metal wires 2 are arranged in parallel and tensioned at both ends, and each coated metal wire 2 is sequentially contacted with the transition layer 3 on the front side of the A heterojunction battery substrates 1, with both ends protruding 11-10mm from the first heterojunction battery substrate 1 and the A heterojunction battery substrate 1, respectively, thus completing the placement of the upper coated metal wires 22;

[0057] Step 2.4: Cover the entire structure obtained in step 2.3 with a high-temperature resistant film, then evacuate to 0.2-80 kPa, press multiple coated metal wires 2 on the front and back sides of A heterojunction battery substrates at 100-300°C, and melt the coating on the surface of the coated metal wires 2 at 130-250°C to complete the hot-press welding.

[0058] The above-mentioned high-temperature resistant film is covered and then vacuumed to ensure that uniform pressure is applied to the coated metal wire 2, so that it is completely attached to the battery surface. After subsequent heating, the entire coated metal wire 2 forms electrical contact with the transition layer 3.

[0059] like Figure 2As shown, the present invention can simultaneously fix the upper plating metal wire 22 and the lower plating metal wire 21. Since the arrangement density of the upper plating metal wire 22 and the lower plating metal wire 21 may be different depending on the heterojunction battery substrate 1 in order to obtain the best electrical performance, the upper plating metal wire 22 and the lower plating metal wire 21 may be aligned or misaligned.

[0060] Step 3: Cut off all the coated metal wires 2 on the side adjacent to each heterojunction battery substrate 1 at a point 70-1mm beyond the edge of the heterojunction battery substrate.

[0061] The plated metal wire 2 on the back of the first battery cell and the front of the Ath battery cell is left uncut, so that in step 6.3 the metal wire can be directly welded to the bus bar 5 to complete the current lead-out;

[0062] The above-mentioned cutting is carried out by mechanical cutting or laser cutting. When mechanical cutting is used, in order to ensure that the ends of the coated metal wires 2 at the edge of the battery will not short-circuit the heterojunction battery substrate 1 after cutting, the spacing between adjacent heterojunction battery substrates 1 should be as small as possible or arranged without spacing. When laser cutting is used, the laser heat energy can be used to retract the ends of the coated metal wires 2, so there can be a 1mm spacing between adjacent heterojunction battery substrates 1.

[0063] Step 4: Remove the transition layer 3 not covered by the coated metal wire 2 using a chemical etching method to obtain the battery cell, such as... Figure 3 As shown;

[0064] Step 5: Sorting the battery cells obtained in Step 4;

[0065] Step 6: Connect the battery cells obtained in step 5 in series using a negative-pitch series connection method;

[0066] Step 6.1: An overlapping area 6 with a width of 0.1 to 1 mm is provided on the front side of the previous battery cell 11 near the edge of the next battery cell 12 and on the back side of the next battery cell 12 near the edge of the previous battery cell 11; this width is to ensure sufficient contact area for conductivity.

[0067] Step 6.2: Apply conductive material 4 to the overlapping area 6 and the surface of the plated metal wire 2 in the overlapping area 6. Then press the two adjacent overlapping areas 6 together so that the plated metal wires 2 in the two overlapping areas 6 are in contact. Figure 4 As shown;

[0068] Considering that the plated metal wire 2 may not be able to make complete contact, in addition to using the plated metal wire 2 for contact, it is necessary to add an additional conductive material 4, such as conductive adhesive or conductive paste, to ensure complete electrical connection.

[0069] Step 6.3: Weld the plated metal wires 2 on the back of the first battery cell and the front of the Ath battery cell to the busbar 5 respectively to draw out the current, thus completing the fabrication of the HJT negative-pitch series battery module. Figure 5 As shown, this eliminates the need to print the main grid and weld the busbars 5 on the surface of the battery cell, reducing light shading on the battery surface and saving processing steps.

[0070] Based on the above-mentioned method for preparing HJT negative-pitch series battery modules, this invention discloses an HJT negative-pitch series battery module, comprising A battery cells connected in series.

[0071] Reference Figure 3 Each battery cell includes a heterojunction battery substrate 1. The front and back sides of the heterojunction battery substrate 1 are sequentially provided with a TCO film 8, a transition layer 3 and a metal layer. The transition layer 3 includes a plurality of parallel conductors. The metal layer includes a plurality of plated metal wires 2 respectively disposed on the front sides of the plurality of first conductors. The distance between the two ends of each plated metal wire 2 and the edge of the heterojunction battery substrate 1 is 0 to 0.1 mm.

[0072] An overlapping area 6 with a width of 0.1 to 1 mm is provided on the front side of the previous battery unit 11 near the edge of the next battery unit 12, and on the back side of the next battery unit 12 near the edge of the previous battery unit 11. A conductive material 4 is provided on the overlapping area 6 and the surface of the plated metal wire 2 of the overlapping area 6. The two adjacent overlapping areas 6 are pressed together.

[0073] The plated metal wires 2 on the back of the first battery cell and the front of the Ath battery cell are welded to the busbar 5 to draw out the current.

Claims

1. A method for fabricating an HJT negative-pitch series battery module, characterized in that, Includes the following steps: Step 1: A transition layer (3) is provided on the TCO film (8) on both the front and back sides of the heterojunction solar cell substrate (1); the transition layer (3) is a single layer or a multilayer structure with a thickness of 10~500 nm; the transition layer (3) is prepared using one or more of copper, zinc, lead, aluminum, nickel, tin and chromium; when the transition layer (3) is a multilayer structure, the materials of each layer can be the same or different. Step 2: On the front and back sides of the A heterojunction battery substrates (1) that have been processed in Step 1 and are arranged side by side and parallel to each other, multiple parallel coated metal wires (2) are set by hot pressing welding. Each coated metal wire (2) contacts the transition layer (3) of the A heterojunction battery substrates (1) in sequence; A is a positive integer greater than 1. Step 3: Cut off all the coated metal wires (2) of each heterojunction battery substrate (1) at a distance of 0-1 mm from the edge (7) of the heterojunction battery substrate (1) adjacent to other heterojunction battery substrates (1); Step 4: Remove the transition layer (3) not covered by the coated metal wire (2) by chemical etching to obtain the battery cell; Step 5: Sorting the battery cells obtained in Step 4; Step 6: Connect the battery cells obtained in step 5 in series using a negative-pitch series connection method; Step 6.1: Set an overlapping area (6) with a width of 0.1~1mm on the front edge of the previous battery cell (11) near the edge of the next battery cell (12) and on the back edge of the next battery cell (12) near the edge of the previous battery cell (11); Step 6.2: Apply conductive material (4) to the overlapping area (6) and the surface of the plated metal wire (2) in the overlapping area (6), and then press the two adjacent overlapping areas (6) together so that the plated metal wire (2) in the two overlapping areas (6) come into contact. Step 6.3: Weld the plated metal wires (2) on the back of the first battery unit and the front of the Ath battery unit to the busbar (5) respectively to complete the fabrication of the HJT negative pitch series battery module.

2. The method for preparing an HJT negative-pitch series battery module according to claim 1, characterized in that, Step 2 specifically involves: Step 2.1: Arrange multiple coated metal wires (2) in parallel and with both ends taut to complete the placement of the lower coated metal wire (21); Step 2.2: Place A heterojunction battery substrates (1) that have been processed in step 1 and are parallel to each other on the lower layer metal wire (21). The spacing between adjacent heterojunction battery substrates (1) is 0~1 mm. Make each metal wire (2) contact the transition layer (3) on the back of the A heterojunction battery substrates (1) in sequence, and make both ends protrude 1~10 mm from the first heterojunction battery substrate (1) and the Ath heterojunction battery substrate (1) respectively. Step 2.3: Above the A heterojunction battery substrates (1) in step 2.2, arrange multiple coated metal wires (2) in parallel and in a state of tension at both ends, and make each coated metal wire (2) contact the transition layer (3) on the front side of the A heterojunction battery substrates (1) in sequence, with both ends protruding 1~10 mm from the first heterojunction battery substrate (1) and the A heterojunction battery substrate (1) respectively, to complete the placement of the upper coated metal wires (22); Step 2.4: Cover the entire structure obtained in step 2.3 with a high-temperature resistant film, then draw a vacuum, and press multiple coated metal wires (2) onto the front and back sides of A heterojunction battery substrates (1) by hot pressing. Then, melt the coating on the surface of the coated metal wires (2) by heating to complete the hot pressing welding.

3. The method for preparing an HJT negative-pitch series battery module according to claim 2, characterized in that: Step 2.4 specifically involves covering the entire structure obtained in step 2.3 with a high-temperature resistant film, then evacuating to 0.2~80 kPa, pressing multiple coated metal wires (2) onto the front and back sides of A heterojunction battery substrates (1) at 100~300 ℃, and melting the coating on the surface of the coated metal wires (2) at 130~250 ℃ to complete the hot-press welding.

4. The method for preparing an HJT negative-pitch series battery module according to claim 1, characterized in that: In step 2, the coating on the surface of the coated metal wire (2) contains one or more of tin, lead, bismuth, indium, and zinc, and the coating thickness is 1~5 μm; The spacing between adjacent parallel coated metal wires (2) is 0.5~3.5 mm, and the outermost coated metal wire (2) is 0.5~3.5 mm away from the edge (7) of the heterojunction battery substrate.

5. The method for preparing an HJT negative-pitch series battery module according to claim 1, characterized in that: In step 3, the severance is performed by mechanical cutting or laser cutting.

6. The method for preparing an HJT negative-pitch series battery module according to claim 1, characterized in that: In step 6.2, the conductive material (4) is a conductive adhesive or a conductive paste.

7. An HJT negative-pitch series battery module, prepared using the preparation method of the HJT negative-pitch series battery module according to claim 1, characterized in that: It includes A battery cells connected in series. Each battery cell includes a heterojunction battery substrate (1). The front and back sides of the heterojunction battery substrate (1) are respectively provided with a TCO film (8), a transition layer (3) and a metal layer. The transition layer (3) includes multiple conductors arranged parallel to each other on the surface of the TCO film (8), and the metal layer includes multiple coated metal wires (2) respectively disposed on the front side of the multiple conductors. The distance between the two ends of each coated metal wire (2) and the edge of the heterojunction battery substrate (1) is 0~0.1 mm. The transition layer (3) is a single-layer or multi-layer structure with a thickness of 10~500 nm. The transition layer (3) is prepared using one or more of copper, zinc, lead, aluminum, nickel, tin, and chromium. When the transition layer (3) is a multi-layer structure, the materials of each layer can be the same or different. An overlapping area (6) with a width of 0.1~1mm is provided on the front edge of the previous battery cell (11) near the edge of the next battery cell (12) and on the back edge of the next battery cell (12) near the edge of the previous battery cell (11). A conductive material (4) is provided on the overlapping area (6) and the surface of the plated metal wire (2) of the overlapping area (6). The two adjacent overlapping areas (6) are pressed together. The plated metal wires (2) on the back of the first battery cell and the front of the Ath battery cell are respectively welded to the busbar (5) to draw out the current.

8. The HJT negative-pitch series battery module according to claim 7, characterized in that: The coating on the surface of the coated metal wire (2) contains one or more of tin, lead, bismuth, indium, and zinc, and the coating thickness is 1~5 μm; The spacing between adjacent parallel coated metal wires (2) is 0.5~3.5 mm, and the outermost coated metal wire (2) is 0.5~3.5 mm away from the edge (7) of the heterojunction battery substrate.

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