Solar cell and grid line structure thereof
By adopting a double-layer gate wire structure in solar cells and using the combination of chromium or chromium alloy layer and metal layer, the adhesion and contact resistance problems between the metal gate wire and the battery body are solved, and the low-cost industrialization of stacked batteries is realized.
Patent Information
- Application Number
- CN202421686347.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-16
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-07-16
AI Technical Summary
In the prior art, the adhesion and contact resistance between the metal gate line and the solar cell body are insufficient, resulting in limited industrialization of stacked batteries and high costs.
A double-layer gate wire structure is adopted, wherein the first gate wire layer is a chromium or chromium alloy layer and the second gate wire layer is a metal layer. It is prepared by physical deposition and printing method to improve adhesion and reduce contact resistance.
High adhesion and low contact resistance between the metal gate line and the battery body are achieved, production costs are reduced, and the industrialization of stacked batteries is conducive to the industrialization of stacked batteries.
Smart Images
Figure CN223142408U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of solar cells, and particularly relates to a grid line structure of a solar cell and a solar cell. Background Art
[0002] The efficiency of perovskite / crystalline silicon tandem cells can currently reach up to 33.9%, far exceeding 27.09% of the mainstream crystalline silicon single-junction cells in the market. Based on the industrial advantages of existing crystalline silicon cells, perovskite / crystalline silicon tandem can better iterate the industry. Coupled with the rich perovskite raw materials, simple preparation and low cost, it is considered the next-generation disruptive photovoltaic technology. The metal grid lines on the front side in solar tandem cells are the key technology for preparing high-efficiency and stable tandem cells.
[0003] Currently, metal grid lines are usually prepared by single-layer thermal evaporation of metallic silver or screen printing of silver. The metallic silver grid lines prepared by thermal evaporation and the transparent electrode at the bottom of the solar cell have a low contact resistance. However, in order to achieve a low line resistance, relatively thick grid lines usually need to be prepared. However, the material utilization rate of thermal evaporation is low, so the realized cost is relatively high. In addition, the adhesion between the metallic silver prepared by thermal evaporation and the transparent electrode is poor, which is not conducive to the industrialization of tandem cells. During the process of screen printing, since the temperature that perovskite can withstand is generally low, this will lead to a high contact resistance between the silver grid lines prepared by screen printing and the transparent electrode, and at the same time, the adhesion between the two is also poor, which limits the application of screen printing in tandem cells. That is to say, single-layer thermal evaporation silver grid lines or printed silver grid lines cannot simultaneously meet the requirements of low line resistance, low contact resistance and high adhesion.
[0004] In order to solve the above problems existing in the prior art, there is an urgent need in the art for an improved grid line technology of solar cells, which can improve the adhesion between the metal grid lines and the battery body, ensure a low contact resistance between the metal grid lines and the battery body, and its cost is controllable, which is conducive to the industrialization of tandem cells. Summary of the Utility Model
[0005] The following gives a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of all aspects nor to attempt to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description to follow.
[0006] In order to overcome the above-mentioned defects existing in the prior art, the present utility model provides a grid line structure of a solar cell and a solar cell, which can improve the adhesion between the metal grid line and the battery body, ensure a low contact resistance between the metal grid line and the battery body, and have controllable costs, which is beneficial to the industrialization of stacked cells.
[0007] Specifically, the grid line structure of the solar cell provided according to the first aspect of the present utility model includes: a first grid line layer located on the surface of the battery body, and the first grid line layer includes chromium; and a second grid line layer located on the upper layer of the first grid line layer, and the second grid line layer is a metal layer.
[0008] Further, in some embodiments of the present utility model, the first grid line layer is a chromium layer or a chromium alloy layer, wherein the chromium alloy layer includes a binary alloy, and the binary alloy includes one of silver-chromium alloy, copper-chromium alloy, and aluminum-chromium alloy.
[0009] Further, in some embodiments of the present utility model, the chromium alloy layer includes a ternary alloy, and the ternary alloy includes one of silver-copper-chromium alloy, aluminum-silver-chromium alloy, and copper-aluminum-chromium alloy.
[0010] Further, in some embodiments of the present utility model, the thickness range of the chromium alloy layer is from 0.1 nm to 1000 nm.
[0011] Further, in some embodiments of the present utility model, the metal layer includes one of silver, copper, aluminum, silver-coated copper, and silver-coated aluminum.
[0012] Further, in some embodiments of the present utility model, the bottom of the back surface of the battery body is a transparent electrode layer, and the first grid line layer is in contact with the transparent electrode layer.
[0013] In addition, the above-mentioned solar cell provided according to the second aspect of the present utility model includes: a battery body, the bottom of the back surface of which includes a transparent electrode layer; and the above-mentioned grid line structure provided according to the first aspect of the present utility model.
[0014] Further, in some embodiments of the present utility model, the battery body includes a perovskite / crystalline silicon stacked cell with perovskite as the top cell and crystalline silicon as the bottom cell.
[0015] Further, in some embodiments of the present utility model, the bottom cell includes a P-type silicon substrate or an N-type silicon substrate, wherein the P-type silicon substrate includes a PERC cell, and the N-type silicon substrate includes any one of a TOPCon cell, an HJT cell, and an IBC cell.
[0016] Further, in some embodiments of the present invention, the chemical general formula of the perovskite of the top cell is ABX3, where A is a monovalent cation or a mixture of monovalent cations, B is a divalent cation or a mixture of divalent cations, and X is a monovalent anion or a mixture of monovalent anions.
[0017] Further, in some embodiments of the present invention, the thickness range of the perovskite of the top cell is 10 nm to 100 μm, and its bandgap range is 0.9 eV to 3.0 eV. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] After reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above features and advantages of the present invention can be better understood. In the drawings, the components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.
[0019] Figure 1 Shows a structural block diagram of a solar cell provided according to some embodiments of the present invention.
[0020] Reference Numerals:
[0021] 100 Solar cell;
[0022] 110 Grid line structure;
[0023] 111 First grid line layer;
[0024] 112 Second grid line layer;
[0025] 120 Cell body;
[0026] 121 Transparent electrode layer;
[0027] 1221 p-type microcrystalline silicon;
[0028] 123 Intrinsic amorphous silicon;
[0029] 124 Crystalline silicon;
[0030] 1222 n-type microcrystalline silicon;
[0031] 1251 Back electrode;
[0032] 1252 Composite layer;
[0033] 126 Hole transport layer;
[0034] 127 Active layer;
[0035] 128 Electron transport layer;
[0036] 129 Buffer layer; and
[0037] 130 electrode. Specific embodiments
[0038] The following specific embodiments illustrate the implementation manners of the present utility model. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. Although the description of the present utility model will be introduced in combination with preferred embodiments, this does not mean that the features of this utility model are limited to this implementation manner. On the contrary, the purpose of introducing the utility model in combination with the implementation manner is to cover other alternatives or modifications that may be extended based on the claims of the present utility model. In order to provide a deep understanding of the present utility model, many specific details will be included in the following description. The present utility model can also be implemented without using these details. In addition, in order to avoid confusing or obscuring the key points of the present utility model, some specific details will be omitted in the description.
[0039] In the description of the present utility model, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.
[0040] In addition, the "upper", "lower", "left", "right", "top", "bottom", "horizontal", and "vertical" used in the following description should be understood as the orientations shown in this section and the related drawings. This relative term is only for the convenience of description and does not mean that the device described needs to be manufactured or operated in a specific orientation. Therefore, it should not be understood as a limitation to the present utility model.
[0041] It can be understood that although the terms "first", "second", "third", etc. can be used here to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first component, region, layer, and / or part discussed below can be referred to as the second component, region, layer, and / or part without departing from some embodiments of the present utility model.
[0042] As described above, the metal silver grid lines prepared by thermal evaporation and the transparent electrode at the bottom of the solar cell have a low contact resistance. However, in order to achieve a low line resistance, it is usually necessary to prepare relatively thick grid lines. However, the material utilization rate of thermal evaporation is low, so the cost of implementation is relatively high. In addition, the adhesion between the metal silver prepared by thermal evaporation and the transparent electrode is poor, which is not conducive to the industrialization of tandem cells. During screen printing, since the temperature that perovskite can withstand is generally low, this will result in a high contact resistance between the silver grid lines and the transparent electrode prepared by screen printing, and the adhesion between the two is also poor, which limits the application of screen printing in tandem cells. That is to say, a single-layer thermally evaporated silver grid line or a printed silver grid line cannot simultaneously meet the requirements of low line resistance, low contact resistance, and high adhesion.
[0043] In order to solve the above problems existing in the prior art, the present utility model provides a grid line structure for a solar cell and a solar cell, which can improve the adhesion between the metal grid line and the cell body, ensure a low contact resistance between the metal grid line and the cell body, and its cost is controllable, which is conducive to the industrialization of tandem cells.
[0044] In some non-limiting embodiments, the above grid line structure of the solar cell provided by the first aspect of the present utility model can be applied to the above solar cell provided by the second aspect of the present utility model.
[0045] The working principle of the above grid line structure of the solar cell will be described below in conjunction with some embodiments of the solar cell. Those skilled in the art can understand that these embodiments of the solar cell are only some non-limiting implementation manners provided by the present utility model, aiming to clearly show the main concept of the present utility model and provide some specific solutions convenient for the public to implement, rather than limiting all the functions of the grid line structure of the solar cell. Similarly, the grid line structure of the solar cell is also only a non-limiting implementation manner provided by the present utility model, and does not limit all the functions of these solar cells.
[0046] Please refer to Figure 1 , Figure 1 which shows a structural block diagram of a solar cell provided according to some embodiments of the present utility model.
[0047] As Figure 1 shown, in some embodiments of the present utility model, the solar cell 100 may include: a cell body 120 and a grid line structure 110. The grid line structure 110 may include a first grid line layer 111 and a second grid line layer 112. The first grid line layer 111 may be located on the surface of the cell body 120, and the first grid line layer 111 includes chromium. The second grid line layer 112 may be located on the upper layer of the first grid line layer 111, and the second grid line layer 112 may be a metal layer.
[0048] Optionally, the first gate line layer 111 can be prepared by physical deposition methods, for example, including but not limited to any one of thin film preparation methods such as vacuum evaporation, magnetron sputtering, arc ion plating, and reactive plasma deposition. The second gate line layer 112 can be prepared by printing.
[0049] Continuing as Figure 1 shown, the bottom of the back surface of the battery body 120 can include a transparent electrode layer 121 for improving the light transmittance of sunlight. The material of the transparent electrode layer 121 can be indium zinc oxide (IZO). The first gate line layer 111 in the gate line structure 110 can be disposed on the upper surface of the transparent electrode layer 121 and in contact with the transparent electrode layer 121. The upper surface here can be understood as the outer layer of the transparent electrode layer 121, and is not limited to the up and down orientation in the figure.
[0050] Since the first gate line layer 111 includes chromium, and the binding of chromium to other metals and the transparent electrode layer 121 is relatively large, which can play an intermediate bonding role, therefore, the adhesion between the gate line structure 110 and the transparent electrode layer 121 can be effectively improved.
[0051] Furthermore, in some alternative embodiments, the first gate line layer 111 can be a chromium layer or a chromium alloy layer. Among them, the chromium alloy layer can include a binary alloy, and the binary alloy can include one of silver chromium (Ag-Cr) alloy, copper chromium (Cu-Cr) alloy, and aluminum chromium (Al-Cr) alloy. By adding a certain amount of silver element to the first gate line layer 111, the corrosion resistance effect of the gate line structure 110 can be improved. By adding a certain amount of copper element to the first gate line layer 111, the density of the gate line structure 110 can be increased, and the contact resistance of the gate line structure 110 can be reduced. By adding a certain amount of aluminum element to the first gate line layer 111, the contact property between the gate line structure 110 and the PN junction of the solar cell can be improved.
[0052] In some other preferred embodiments, the chromium alloy layer of the first gate line layer 111 can further include a ternary alloy, and the ternary alloy can include one of silver copper chromium (Ag-Cu-Cr) alloy, aluminum silver chromium (Al-Ag-Cr) alloy, and copper aluminum chromium (Cu-Al-Cr) alloy.
[0053] Furthermore, the thickness range of the chromium alloy layer of the first gate line layer 111 can preferably be in the range of 0.1 nm to 1000 nm. If the thickness of the first gate line layer 111 is less than 0.1 nm, it will not be able to play the role of improving adhesion, while if the thickness of the first gate line layer 111 is greater than 1000 nm, its commercial price is relatively high.
[0054] Continuing as Figure 1As shown, the metal layer of the second gate line layer 112 in the gate line structure 110 may include one of silver, copper, aluminum, silver-coated copper, and silver-coated aluminum. Moreover, the thickness range of the printed second gate line layer 112 may be between 1 μm and 50 μm. By screen-printing the second gate line layer 112 (e.g., silver gate lines), a lower sheet resistance of the gate lines can be ensured.
[0055] In an embodiment of the present invention, the double-layer gate line structure 110 composed of the chromium alloy first gate line layer 111 and the metal second gate line layer 112 can not only keep the gate line structure 110 having a lower sheet resistance, but also maintain a lower contact resistance between the gate line structure 110 and the transparent electrode layer 121, thereby reducing electrical losses, and can also improve the adhesion between the gate line structure 110 and the transparent electrode layer 121.
[0056] In some embodiments of the present invention, the cell body 120 in the solar cell 100 may include a perovskite / crystalline silicon tandem cell with a perovskite as the top cell and a crystalline silicon as the bottom cell.
[0057] The chemical general formula of the perovskite in the top cell of the cell body 120 may be ABX3, where A is a monovalent cation, including but not limited to cesium (Cs), rubidium (Rb), methylammonium (CH3NH3), formamidinium (CH2(NH2)2), or a mixture of several monovalent cations; B is a divalent cation, including but not limited to lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn), calcium (Ca), or a mixture of several divalent cations; and X is a monovalent anion, including but not limited to iodine (I), bromine (Br), chlorine (Cl), fluorine (F), and thiocyanate ion (SCN), or a mixture of monovalent anions.
[0058] Optionally, the preparation method of the perovskite layer may include but not limited to one or more of spin coating, blade coating, evaporation coating, printing, spraying, spray pyrolysis, and slot die coating. The thickness range of the perovskite layer may be from 10 nm to 100 μm, and its bandgap range may be from 0.9 eV to 3.0 eV.
[0059] The bottom cell in the cell body 120 may include a P-type silicon substrate or an N-type silicon substrate. Among them, the P-type silicon substrate may include but not limited to PERC cells, and the N-type silicon substrate may include but not limited to any one of TOPCon cells, HJT cells, and IBC cells.
[0060] To better introduce a solar cell 100 and its gate line structure 110 provided by the present invention, the following will introduce a preparation method of a perovskite / crystalline silicon tandem solar cell.
[0061] As Figure 1As shown, in some embodiments, N-type (n-type) crystalline silicon 124 (c-Si) with a resistivity of 2 Ω·cm can be selected as the substrate light absorption region, i.e., the bottom cell. The thickness of the crystalline silicon 124 can be 300 μm. Since there are many defects on the surface of the crystalline silicon 124 (c-Si), Plasma Enhanced Chemical Vapor Deposition (PECVD) technology can be used to deposit intrinsic amorphous silicon 123 (i-a-Si) with a thickness of 5 nm on both the front and back surfaces of the crystalline silicon 124 to better passivate the surface of the crystalline silicon 124 (c-Si).
[0062] Continue to use the PECVD technology to deposit n-type microcrystalline silicon 125 (n-uc-Si) on the front surface of the intrinsic amorphous silicon 123 (i-a-Si), and deposit p-type microcrystalline silicon 1221 (p-uc-Si) on the back surface of the intrinsic amorphous silicon 123 as the carrier selective layer. Further, in order to prepare the tunneling layer, p-type microcrystalline silicon 1221 (p-uc-Si) can also be deposited on the upper layer of the n-type microcrystalline silicon 1222 (n-uc-Si) to improve the fill factor of the battery.
[0063] After that, magnetron sputtering can be used to deposit 80 nm of indium tin oxide (ITO) on the surface of the p-type microcrystalline silicon 1221 (p-uc-Si) on the back as the back electrode 1251, and deposit 20 nm of indium tin oxide (ITO) on the surface of the p-type microcrystalline silicon 1221 (p-uc-Si) on the front as the composite layer 1252. In this embodiment, the back of the battery body 120 must include indium tin oxide (ITO) or a similar transparent conductive material as the back electrode 1251, otherwise current collection cannot be achieved. If the indium tin oxide composite layer 1252 in the middle is removed, the fill factor of the battery will decrease.
[0064] After that, 20 nm of nickel oxide can be deposited on the upper layer of the composite layer 1252 by magnetron sputtering as the hole transport layer 126 to improve the hole transport rate in the device. Slot coating is used to prepare perovskite as the active layer 127 (Perovskite) to effectively convert the absorbed light energy into electrical energy in the solar cell 100. The thickness of the active layer 127 can be 1000 nm. And, 30 nm of C60 is thermally evaporated and set as the electron transport layer 128 above the active layer 127.
[0065] Further, preferably, above the electron transport layer 128, tin dioxide (SnO2) with a thickness of 20 nm can also be prepared by Atomic Layer Deposition (ALD) technology as the buffer layer 129 to reduce the sputtering damage to the active layer 127 (perovskite) during the preparation process of the subsequent transparent electrode layer 121.
[0066] Above the buffer layer 129, indium zinc oxide (IZO) with a thickness of 100 nm can be prepared by magnetron sputtering as the transparent electrode layer 121. On the upper surface of the transparent electrode layer 121, a silver-chromium (Ag-Cr) alloy with a thickness of 100 nm can be prepared by magnetron sputtering as the first gate line layer 111 to improve the adhesion with the transparent electrode layer 121 and ensure a low contact resistance between the gate line structure 110 and the transparent electrode layer 121. Then, a front metal silver gate line can be prepared on the first gate line layer 111 by screen printing as the second gate line layer 112 to ensure that the gate line structure 110 has a low line resistance. Similarly, a back metal silver electrode 130 can also be made on the back of the battery body 120 by screen printing.
[0067] Those skilled in the art can understand that the chromium alloy material selected for the first gate line layer 111 and the metal material of the second gate line layer 112 are only a non-limiting implementation manner provided by the present utility model, aiming to clearly show the main concept of the present utility model and provide a specific solution convenient for the public to implement, rather than limiting the protection scope of the present utility model.
[0068] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions that are illustrated and described herein or not illustrated and described herein but are understandable to those skilled in the art.
[0069] In summary, the present utility model provides a gate line structure of a solar cell and a solar cell, which can improve the adhesion between the metal gate line and the battery body, ensure a low contact resistance between the metal gate line and the battery body, and have controllable cost, which is beneficial to the industrialization of the tandem battery.
[0070] The previous description of the present disclosure is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A grid line structure of a solar cell, characterized in that, Comprising: A first grid line layer, located on the surface of the battery body, and the first grid line layer includes chromium; and A second grid line layer, located above the first grid line layer, and the second grid line layer is a metal layer.
2. The gate line structure according to claim 1, wherein The first grid line layer is a chromium layer or a chromium alloy layer, wherein the chromium alloy layer includes a binary alloy, and the binary alloy includes one of silver chromium alloy, copper chromium alloy, and aluminum chromium alloy.
3. The gate line structure according to claim 2, wherein The chromium alloy layer includes a ternary alloy, and the ternary alloy includes one of silver copper chromium alloy, aluminum silver chromium alloy, and copper aluminum chromium alloy.
4. The gate line structure according to claim 2, wherein The thickness range of the chromium alloy layer is from 0.1 nm to 1000 nm.
5. The gate line structure according to claim 1, wherein, The metal layer includes one of silver, copper, aluminum, silver-coated copper, and silver-coated aluminum.
6. The gate line structure according to claim 1, wherein The bottom of the back surface of the battery body is a transparent electrode layer, and the first grid line layer is in contact with the transparent electrode layer.
7. A solar cell, characterized in that, Comprising: A battery body, the bottom of the back surface of which includes a transparent electrode layer; and The grid line structure according to any one of claims 1 to 6.
8. The solar cell according to claim 7, characterized in that, The battery body includes a perovskite / crystalline silicon tandem battery with perovskite as the top cell and crystalline silicon as the bottom cell.
9. The solar cell according to claim 8, wherein, The bottom cell includes a P-type silicon substrate or an N-type silicon substrate, wherein the P-type silicon substrate includes a PERC cell, and the N-type silicon substrate includes any one of a TOPCon cell, an HJT cell, and an IBC cell.
10. The solar cell according to claim 8, characterized in that, The chemical general formula of the perovskite of the top cell is ABX3, wherein A is a monovalent cation or a mixture of monovalent cations, B is a divalent cation or a mixture of divalent cations, and X is a monovalent anion or a mixture of monovalent anions.
11. The solar cell according to claim 8, characterized in that, The thickness range of the perovskite of the top cell is from 10 nm to 100 μm, and its band gap range is from 0.9 eV to 3.0 eV.