A novel topcon cell and a novel solar module

Abstract

The utility model relates to solar cell technical field discloses a novel TOPCon battery and novel solar cell module. The novel TOPCon battery, including silicon wafer, the back surface of silicon wafer is equipped with passivation contact structure, the electrode contact area of passivation contact structure back surface is equipped with first finger electrode, the line width of first finger electrode is equal to or less than 12mu m, and first finger electrode includes the first titanium metal electrode, first aluminum metal electrode and first copper metal electrode that passivation contact structure is sequentially ohmic contact, the non electrode contact area of passivation contact structure back surface is equipped with first passivation antireflection film, and the back of first finger electrode extends first passivation antireflection film back surface. The novel TOPCon battery is matched with the above-mentioned narrow line width first finger electrode through passivation contact structure, can reduce shading loss, can improve passivation effect, reduces contact resistance, improves the conversion efficiency of battery, and first finger electrode adopts non-silver electrode material, and material cost is lower.

Description

Technical Field

[0001] This utility model relates to the field of solar cell technology, specifically to a novel TOPCon battery and a novel solar cell module. Background Technology

[0002] With the increasing demand for high-efficiency solar cells in the photovoltaic industry, TOPCon (Tunnel Oxide Passivated Contact) technology, with its excellent passivation contact performance and theoretical efficiency limit (>28%), has become one of the important directions for next-generation mainstream solar cell technologies. The core advantage of TOPCon cells lies in their passivation contact structure on the back (which includes a tunnel oxide layer + a doped polycrystalline silicon layer), but the metallization process of the front or back electrodes still faces limitations imposed by traditional screen printing technology.

[0003] 1. Light-blocking loss: The line width of silver grid lines in screen printing is usually 30-40μm, and the light-blocking area is large.

[0004] 2. High contact resistance: High-temperature sintering of electrodes (or grid lines) can easily damage the passivation layer and passivation contact structure, leading to increased carrier recombination and high contact resistance.

[0005] 3. High material costs: The production of electrodes (or grid lines) requires a large amount of silver paste, and the high price of silver paste will increase the production cost of solar cells; in practice, the cost of electrodes (or grid lines) accounts for 20-30% of the total cost of solar cells.

[0006] Therefore, in the electrode metallization process of TOPCon batteries, achieving a high-efficiency electrode structure with low resistance, low light loss, and low cost is one of the core challenges.

[0007] Existing electrode metallization technologies, such as those disclosed in CN117894856A and CN111769165A, provide a multi-finger technology based on Physical Vapor Deposition (PVD) to prepare solar cell electrodes (Poly Fingers technology, which refers to the deposition of multiple independent finger-like structures on silicon wafers using PVD methods in semiconductor manufacturing). Poly Fingers technology, through the deep integration of PVD processes and material interface engineering, can provide a high-precision, low-cost solution for solar cell electrode metallization processes. This helps resolve the efficiency and cost contradiction in solar cell electrode metallization, providing an important technological path for the photovoltaic industry to achieve the goal of "cost reduction and efficiency improvement," and is expected to accelerate the development of photovoltaic electrodes towards "silver-free" and "ultra-fine grid lines."

[0008] Although the fabrication of ultrafine, low-cost metal electrodes using PVD technology has become an important research direction, achieving low-damage, high-precision electrodes on doped polycrystalline silicon layers in TOPCon cells remains a pressing technical challenge. Utility Model Content

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a new type of TOPCon battery and a new type of solar cell module.

[0010] Based on this, the present invention discloses a novel TOPCon battery, including a silicon wafer, the back of which is provided with a passivation contact structure; the electrode contact area on the back of the passivation contact structure is provided with a first finger electrode, the linewidth of the first finger electrode is ≤12μm, and the first finger electrode includes a first titanium metal electrode, a first aluminum metal electrode and a first copper metal electrode with sequential ohmic contact passivation contact structure.

[0011] The non-electrode contact area on the back of the passivated contact structure is provided with a first passivation antireflection film, and the back of the first finger electrode extends out of the back of the first passivation antireflection film.

[0012] Preferably, the front side of the silicon wafer is further provided with an emitter, and the electrode contact area on the front side of the emitter is provided with a second finger electrode, the second finger electrode including a second titanium metal electrode, a second aluminum metal electrode and a second copper metal electrode that are in ohmic contact with the emitter in sequence;

[0013] The linewidths of both the first and second finger electrodes are ≤10μm.

[0014] More preferably, the thickness of the first titanium metal electrode and the second titanium metal electrode is 30-50 nm, the thickness of the first aluminum metal electrode and the second aluminum metal electrode is 100-200 nm, and the thickness of the first copper metal electrode and the second copper metal electrode is 1-2 μm.

[0015] More preferably, the thickness of the first titanium metal electrode and the second titanium metal electrode is 35-40 nm, the thickness of the first aluminum metal electrode and the second aluminum metal electrode is 111-120 nm, and the thickness of the first copper metal electrode and the second copper metal electrode is 1.1-1.2 μm.

[0016] More preferably, an interface passivation layer is provided between the first titanium metal electrode and the passivation contact structure, and / or between the second titanium metal electrode and the emitter; the interface passivation layer is titanium oxide, and its thickness is 15-25 nm.

[0017] More preferably, the emitter is a P+ emitter formed by diffusion, and the sheet resistance after diffusion is 300-400Ω / □.

[0018] More preferably, the non-electrode contact area on the front side of the emitter is provided with a second passivation antireflection film, and the outer end of the second finger electrode extends out of the front side of the second passivation antireflection film; the second passivation antireflection film includes a second passivation film and a second antireflection film sequentially disposed in the non-electrode contact area on the front side of the emitter.

[0019] The first passivation antireflection film includes a first passivation film and a first antireflection film sequentially disposed on the non-electrode contact area on the back side of the passivation contact structure;

[0020] Both the first passivation film and the second passivation film are aluminum oxide films with a thickness of 2-20 nm and a refractive index of 1.6-1.68, and both the first antireflection film and the second antireflection film are silicon nitride films with a thickness of 60-95 nm and a refractive index of 1.95-2.27.

[0021] Preferably, the passivation contact structure includes a tunneling oxide layer, a doped polysilicon layer and a heavily doped polysilicon layer sequentially disposed on the back side of the silicon wafer, wherein the heavily doped polysilicon is disposed on a patterned mask area on the back side of the doped polysilicon layer, and the electrode contact area on the back side of the heavily doped polysilicon ohmically contacts the first finger electrode.

[0022] The doped polycrystalline silicon layer is an N+ polycrystalline silicon layer with a thickness of 110-130 nm; the heavily doped polycrystalline silicon is N++ polycrystalline silicon.

[0023] Preferably, the silicon wafer is a texturized silicon wafer, which has a weight reduction of 0.3-0.7g and a reflectivity of 9-13%; the back side of the texturized silicon wafer is a polished surface, which has a weight reduction of 0.2-0.5g and a reflectivity of 35-60%.

[0024] This utility model also discloses a novel solar cell module, which includes the novel TOPCon battery described above.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] This novel TOPCon battery, through the combination of a passivated contact structure and a first finger electrode, wherein the linewidth of the first finger electrode is ≤12μm, and the first finger electrode comprises a first titanium metal electrode, a first aluminum metal electrode, and a first copper metal electrode with sequential ohmic contact passivation structures; firstly, the linewidth of the first finger electrode is reduced from the conventional 40μm to below 12μm (preferably below 10μm), which helps to reduce the light-shielding area of ​​the electrode, thereby reducing light-shielding loss; secondly, through the combination of the passivated contact structure and the aforementioned first finger electrode, the passivation effect and contact performance of the battery can be further improved, reducing thermal damage and carrier recombination, and the contact resistance of the battery can be reduced to 0.8mΩ·cm.2 This can improve the battery's conversion efficiency; thirdly, the first finger electrode uses non-silver electrode material, which greatly reduces the cost of electrode material and meets the requirements of mass production. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the cross-sectional structure of a novel TOPCon battery according to this embodiment.

[0028] Reference numerals: 1. Silicon wafer; 2. Tunneling oxide layer; 3. Doped polycrystalline silicon layer; 4. Heavily doped polycrystalline silicon; 5. First finger electrode; 51. First interface passivation layer; 52. First titanium metal electrode; 53. First aluminum metal electrode; 54. First copper metal electrode; 6. First passivation film; 7. First antireflection film; 8. Emitter; 9. Second finger electrode; 91. Second interface passivation layer; 92. Second titanium metal electrode; 93. Second aluminum metal electrode; 94. Second copper metal electrode; 10. Second passivation film; 11. Second antireflection film. Detailed Implementation

[0029] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Example

[0031] This embodiment describes a novel TOPCon battery, see [link to previous document]. Figure 1 This includes silicon wafer 1. In practice, silicon wafer 1 is a texturized silicon wafer 1, which reduces weight by 0.3-0.7g and has a reflectivity of 9-13%; thus, the front side of the texturized silicon wafer 1 is a textured surface. Furthermore, the back side of the texturized silicon wafer 1 is a polished surface, which reduces weight by 0.2-0.5g, and has a reflectivity of 35-60%. That is, the front side of silicon wafer 1 is a textured surface, while the back side of silicon wafer 1 is a polished surface.

[0032] In this novel TOPCon cell, a tunneling oxide layer 2 and a doped polycrystalline silicon layer 3 are sequentially disposed on the back side of the silicon wafer 1. A heavily doped polycrystalline silicon layer 4 is disposed on the patterned mask region on the back side of the doped polycrystalline silicon layer 3. Specifically, the doped polycrystalline silicon layer 3 is an N+ polycrystalline silicon layer with a thickness of 110-130 nm; the heavily doped polycrystalline silicon layer 4 is N++ polycrystalline silicon. That is, the passivation contact structure on the back side of this novel TOPCon cell includes a tunneling oxide layer 2, a doped polycrystalline silicon layer 3, and a heavily doped polycrystalline silicon layer 4.

[0033] Furthermore, an emitter 8 is provided on the front side of the silicon wafer 1. Specifically, the emitter 8 is a P+ emitter 8 formed by diffusion, and the sheet resistance after diffusion is 300-400Ω / □.

[0034] The electrode contact area on the back of the heavily doped polycrystalline silicon 4 with passivated contact structure is provided with a first finger electrode 5. The first finger electrode 5 includes a first titanium metal electrode 52, a first aluminum metal electrode 53 and a first copper metal electrode 54 that are in ohmic contact with the heavily doped polycrystalline silicon 4 in sequence.

[0035] Furthermore, the electrode contact area on the front side of the emitter 8 is provided with a second finger electrode 9, which includes a second titanium metal electrode 92, a second aluminum metal electrode 93, and a second copper metal electrode 94 that are in ohmic contact with the emitter 8 in sequence.

[0036] Specifically, the linewidths of the first finger electrode 5 and the second finger electrode 9 are both ≤12μm (preferably ≤10μm).

[0037] Specifically, the thickness of the first titanium metal electrode 52 and the second titanium metal electrode 92 is 30-50nm (preferably 35-40nm), the thickness of the first aluminum metal electrode 53 and the second aluminum metal electrode 93 is 100-200nm (preferably 111-120nm), and the thickness of the first copper metal electrode 54 and the second copper metal electrode 94 is 1-2μm (preferably 1.1-1.2μm).

[0038] Furthermore, an interface passivation layer is provided between the first titanium metal electrode 52 and the heavily doped polycrystalline silicon 4, and / or between the second titanium metal electrode 92 and the emitter 8. Preferably, a first interface passivation layer 51 is provided between the first titanium metal electrode 52 and the heavily doped polycrystalline silicon 4, and a second interface passivation layer 91 is provided between the second titanium metal electrode 92 and the emitter 8; both the first interface passivation layer 51 and the second interface passivation layer 91 are titanium oxide (TiOx) with a thickness of 15-25 nm (preferably 20 nm).

[0039] In practice, the first finger electrode 5 and the second finger electrode 9 are fabricated using a self-aligned patterned mask technique: laser etching or nanoimprinting is used to form specific patterned masks on both the back side of the passivated contact structure and the front side of the emitter 8. During PVD deposition, the electrode material can be automatically deposited directly according to the shape and position of the patterned mask to form high-precision patterned finger electrodes (i.e., the first finger electrode 5 and the second finger electrode 9). In this way, there is no need for the complex alignment steps required by traditional photolithography, avoiding the complexity and high cost of traditional photolithography. Moreover, PVD (such as magnetron sputtering or electron beam evaporation) is a low-temperature deposition process, which can deposit the first finger electrode 5 and the second finger electrode 9 at ≤200℃, avoiding thermal damage to the passivated contact structure and tunneling oxide layer 2 caused by high temperature. This is beneficial for reducing carrier recombination and improving the electrical performance of the battery.

[0040] The first finger electrode 5 and the second finger electrode 9 of this novel TOPCon battery both adopt a multi-layer stacked design: that is, the first finger electrode 5 and the second finger electrode 9 are both deposited with a gradient of metals Ti, Al and Cu, and combined with an interface passivation layer (such as TiOx), which can suppress the diffusion of metal to the passivation contact structure or the emitter 8, improve the contact performance and passivation efficiency of the battery, and improve the adhesion of the first finger electrode 5 and the second finger electrode 9.

[0041] This novel TOPCon battery, through PVD deposition and low-temperature annealing, sequentially forms a first interface passivation layer 51, a first titanium metal electrode 52, a first aluminum metal electrode 53, and a first copper metal electrode 54 on the electrode contact area on the back of a passivated contact structure (such as heavily doped polycrystalline silicon 4). This forms a first finger electrode 5 with a linewidth ≤10μm. The combination of the passivated contact structure and the first finger electrode 5 reduces contact resistance. Furthermore, the small linewidth of the first finger electrode 5 and the second finger electrode 9 reduces light-shielding loss. Both the first finger electrode 5 and the second finger electrode 9 use non-silver electrode materials, significantly reducing material costs.

[0042] The non-electrode contact area on the back of the passivated contact structure is provided with a first passivation antireflection film. The first passivation antireflection film includes a first passivation film 6 and a first antireflection film 7 disposed on the back of the first passivation film 6. The back of the first finger electrode 5 extends out of the back of the first antireflection film 7. The first passivation film 6 is disposed in the non-electrode contact area on the back of the heavily doped polysilicon 4 and the non-patterned mask area on the back of the doped polysilicon layer 3.

[0043] Furthermore, a second passivation antireflection film is provided in the non-electrode contact area on the front side of the emitter 8. The second passivation antireflection film includes a second passivation film 10 and a second antireflection film 11 sequentially disposed in the non-electrode contact area on the front side of the emitter 8; the outer end of the second finger electrode 9 extends out of the front side of the second antireflection film 11.

[0044] Specifically, both the first passivation film 6 and the second passivation film 10 are aluminum oxide films with a thickness of 2-20 nm and a refractive index of 1.6-1.68, and both the first antireflection film 7 and the second antireflection film 11 are silicon nitride films with a thickness of 60-95 nm and a refractive index of 1.95-2.27. Moreover, the thickness of the first passivation antireflection film is controlled at 80-100 nm.

[0045] In summary, this novel TOPCon battery, through the combination of a passivated contact structure and the first finger electrode 5, as well as the combination of the first finger electrode 5 and the second finger electrode 9, achieves two key benefits: First, the linewidth of the first finger electrode 5 and the second finger electrode 9 is reduced from the traditional 40 μm to below 10 μm, resulting in a 60% reduction in the electrode light-shielding area on the front of the battery, significantly reducing light-shielding loss. Second, the combination of the passivated contact structure and the first finger electrode 5 further enhances the passivation effect and contact performance of the battery, reducing thermal damage and carrier recombination, and lowering the battery's contact resistance to 0.8 mΩ·cm. 2 First, its fill factor is increased to over 84%, which helps to improve the conversion efficiency of the battery; second, both the first finger electrode 5 and the second finger electrode 9 use non-silver electrode materials, reducing the cost of electrode materials by 30-50%.

[0046] This embodiment provides a novel solar cell module, which includes the novel TOPCon cell described above.

[0047] Examples 1 and 2 illustrate a method for preparing a novel TOPCon battery as described above in this embodiment, as detailed below: Example 1

[0048] This example illustrates a novel method for fabricating a TOPCon battery. See [link to relevant documentation]. Figure 1 The preparation steps include the following:

[0049] Step 1, Texturing: Before texturing, silicon wafer 1 is first divided into equal pieces (i.e., finely divided silicon wafer 1 to ensure the consistency of silicon wafer 1); 1000 selected N-type silicon wafers 1 with resistivity of 0.4-1.6 Ω·cm are sequentially cleaned, texturized, acid-washed, water-washed, and dried to obtain texturized silicon wafer 1. In Step 1, the weight reduction of the texturized silicon wafer 1 is controlled to 0.5g, and the reflectivity is controlled to 11%.

[0050] Step 2, Boron diffusion: Boron diffusion and oxidation are performed on the texturized silicon wafer 1 to form a P+ emitter 8 on the front side of the silicon wafer 1. The sheet resistance after diffusion is 350Ω / □.

[0051] Step 3: Remove back borosilicate glass (BSG): Clean the back side of silicon wafer 1 with HF solution to remove the BSG formed on the back side of silicon wafer 1 during boron diffusion.

[0052] Step 4, Alkaline Etching and Polishing: The back side of silicon wafer 1 is etched and polished using a mixed alkaline solution of sodium hydroxide and additives (such as existing sodium silicate and surfactants) to form a polished surface on the back side of silicon wafer 1. In Step 4, the weight reduction from polishing is controlled at 0.25g, and the reflectivity of the polished surface is controlled at 40%.

[0053] Step 5: Deposit tunneling oxide layer 2 and N+ polysilicon layer: Using plasma-enhanced chemical vapor deposition (PECVD) technology, tunneling oxide layer 2 and 120nm thick N+ polysilicon layer (i.e. phosphorus-doped polysilicon layer 3) are sequentially deposited on the back side of the polished silicon wafer 1.

[0054] Step 6, Remove front-side phosphosilicate glass (PSG): Clean the silicon wafer 1 after step 5 with HF solution to remove the PSG formed on the front side of the emitter 8 during the PECVD deposition process.

[0055] Step 7: Forming a patterned mask: Using laser direct writing or nanoimprinting, a patterned mask is formed on both the back side of the N+ polysilicon layer and the front side of the emitter 8. The opening width of the patterned mask is controlled at 10μm. At the same time, during the formation of the patterned mask, the patterned mask area on the back side of the N+ polysilicon layer is transformed into N++ polysilicon due to laser phosphorus heavy doping.

[0056] Step 8, PVD Deposition: Using physical vapor deposition, electrode material is deposited on the patterned electrode contact area (i.e., the patterned opening area of ​​the patterned mask) of the patterned mask. Thus, a first titanium metal electrode 52 with a thickness of 35 nm, a first aluminum metal electrode 53 with a thickness of 120 nm, and a first copper metal electrode 54 with a thickness of 1.1 μm are sequentially deposited on the electrode contact area on the back side of the N++ polysilicon to obtain a first finger electrode 5 with a linewidth of 10 μm. On the electrode contact area on the front side of the P+ emitter 8, a second titanium metal electrode 92 with a thickness of 35 nm, a second aluminum metal electrode 93 with a thickness of 120 nm, and a second copper metal electrode 94 with a thickness of 1.1 μm are sequentially deposited to obtain a second finger electrode 9 with a linewidth of 10 μm.

[0057] Step 9, Annealing: The silicon wafer 1 from Step 8 is annealed at 185°C for 35 minutes to optimize the interface passivation contact, forming a first interface passivation layer 51 between the first titanium metal electrode 52 and the N++ polysilicon, and a second interface passivation layer 91 between the second titanium metal electrode 92 and the P+ emitter 8. In Step 9, both the first interface passivation layer 51 and the second interface passivation layer 91 are 20 nm thick titanium oxide (TiOx).

[0058] Step 10, Patterned Mask Stripping: The patterned mask material is removed by etching with HF solution to complete the fabrication of the finger electrodes.

[0059] Step 11, Alumina Film: Alumina with a thickness of 3 nm and a refractive index of 1.62 is deposited on both the back and front sides of the silicon wafer 1 after the treatment in Step 10, serving as the first passivation film 6 and the second passivation film 10, respectively. In Step 11, the first passivation film 6 is deposited on the non-electrode contact area on the back side of the N++ polysilicon layer and the non-patterned mask area on the back side of the N+ polysilicon layer; while the second passivation film 10 is deposited on the non-electrode contact area on the front side of the P+ emitter 8.

[0060] Step 12, Second Antireflection Coating 11: Using PECVD deposition technology, a 60nm thick silicon nitride film with a refractive index of 1.95 is deposited on the front side of the second passivation film 10 in step 11 as the second antireflection coating 11.

[0061] Step 13, First antireflection film 7: Using PECVD deposition technology, a 95nm thick silicon nitride film with a refractive index of 1.95 is deposited on the back side of the first passivation film 6 in step 11 as the first antireflection film 7.

[0062] After processing in step 13, the result is as follows: Figure 1 The example shown is a novel TOPCon battery.

[0063] Example 2

[0064] This example illustrates a novel method for fabricating a TOPCon battery. See [link to relevant documentation]. Figure 1 The specific preparation steps are the same as in Example 1, but the difference between Example 1 and Example 1 is:

[0065] In step 8 of this example, the thickness of the first titanium metal electrode 52 and the second titanium metal electrode 92 is 40 nm, the thickness of the first aluminum metal electrode 53 and the second aluminum metal electrode 93 is 111 nm, and the thickness of the first copper metal electrode 54 and the second copper metal electrode 94 is 1.2 μm.

[0066] In step 9 of this example, the annealing conditions are changed to: annealing at 190°C for 40 minutes.

[0067] Comparative Example 1

[0068] The preparation method of this comparative example of a novel TOPCon battery follows the same steps as in Example 1, but differs from Example 1 in that:

[0069] Steps 7-10 of Example 1 are omitted; after completing step 6 of Example 1, steps 11-13 of Example 1 are executed directly; after step 13 of Example 1, the following metallization process is also included:

[0070] The back electrode and the front electrode (to replace the first and second finger electrodes of Example 1, respectively) are prepared by using the existing screen printing and high-temperature sintering method; wherein the screen printing paste is silver paste and the high-temperature sintering temperature is 890°C.

[0071] Performance testing

[0072] The electrical performance of the TOPCon batteries prepared in Examples 1-2 and Comparative Example 1 was tested, and the test results are shown in Table 1 below:

[0073] Table 1

[0074]

[0075] In Table 1, Eta is the battery conversion efficiency, Uoc is the open-circuit voltage, Isc is the short-circuit current, FF is the fill factor, Rs is the series resistance, and Rsh is the parallel resistance.

[0076] Referring to Table 1, it can be seen that the novel TOPCon cells of Examples 1 and 2 in this embodiment, based on the passivated contact structure (which includes a tunneling oxide layer, a doped polycrystalline silicon layer, and heavily doped polycrystalline silicon), are equipped with finger electrodes with a linewidth of 10 μm (the finger electrodes include titanium metal electrodes, aluminum metal electrodes, and copper metal electrodes in sequence). Thus, compared with Comparative Example 1, the conversion efficiency, open-circuit voltage, short-circuit current, and fill factor of the novel TOPCon cells of Examples 1 and 2 are all improved; for example, the conversion efficiency of the novel TOPCon cell of Example 1 is as high as 26.75%, which is 0.2% higher than the conversion efficiency of 26.55% of the TOPCon cell prepared by the conventional screen printing process shown in Comparative Example 1. Moreover, compared with Comparative Example 1, the novel TOPCon cells of Examples 1 and 2 can also reduce contact resistance (i.e., lower series resistance), and have higher parallel resistance, and the leakage current inside the cell is significantly improved, thus effectively avoiding thermal damage and carrier recombination to the passivated contact structure.

[0077] In addition, the finger electrodes of the new TOPCon batteries in Examples 1 and 2 have small linewidths, which can greatly reduce the shading area and reduce shading loss. Moreover, the finger electrodes are silver-free electrodes, which are low in cost and meet the requirements of mass production.

[0078] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0079] The technical solution provided by this utility model has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A novel TOPCon battery, characterized in that, The device includes a silicon wafer, the back of which is provided with a passivation contact structure; the electrode contact area on the back of the passivation contact structure is provided with a first finger electrode, the linewidth of the first finger electrode is ≤12μm, and the first finger electrode includes a first titanium metal electrode, a first aluminum metal electrode and a first copper metal electrode with sequential ohmic contact passivation contact structures. The non-electrode contact area on the back of the passivated contact structure is provided with a first passivation antireflection film, and the back of the first finger electrode extends out of the back of the first passivation antireflection film.

2. The novel TOPCon battery according to claim 1, characterized in that, The silicon wafer is also provided with an emitter on the front side, and the electrode contact area on the front side of the emitter is provided with a second finger electrode. The second finger electrode includes a second titanium metal electrode, a second aluminum metal electrode, and a second copper metal electrode that are in ohmic contact with the emitter in sequence. The linewidths of both the first and second finger electrodes are ≤10μm.

3. The novel TOPCon battery according to claim 2, characterized in that, The thickness of the first titanium metal electrode and the second titanium metal electrode is 30-50 nm, the thickness of the first aluminum metal electrode and the second aluminum metal electrode is 100-200 nm, and the thickness of the first copper metal electrode and the second copper metal electrode is 1-2 μm.

4. A novel TOPCon battery according to claim 3, characterized in that, The thickness of the first titanium metal electrode and the second titanium metal electrode is 35-40 nm, the thickness of the first aluminum metal electrode and the second aluminum metal electrode is 111-120 nm, and the thickness of the first copper metal electrode and the second copper metal electrode is 1.1-1.2 μm.

5. A novel TOPCon battery according to claim 2, characterized in that, An interface passivation layer is provided between the first titanium metal electrode and the passivation contact structure, and / or between the second titanium metal electrode and the emitter; the interface passivation layer is titanium oxide, and its thickness is 15-25 nm.

6. A novel TOPCon battery according to claim 2, characterized in that, The emitter is a P+ emitter formed by diffusion, and the sheet resistance after diffusion is 300-400Ω / □.

7. A novel TOPCon battery according to claim 2, characterized in that, The non-electrode contact area on the front of the emitter is provided with a second passivation antireflection film, and the outer end of the second finger electrode extends out of the front of the second passivation antireflection film; the second passivation antireflection film includes a second passivation film and a second antireflection film sequentially disposed in the non-electrode contact area on the front of the emitter. The first passivation antireflection film includes a first passivation film and a first antireflection film sequentially disposed on the non-electrode contact area on the back side of the passivation contact structure; Both the first passivation film and the second passivation film are aluminum oxide films with a thickness of 2-20 nm and a refractive index of 1.6-1.68, and both the first antireflection film and the second antireflection film are silicon nitride films with a thickness of 60-95 nm and a refractive index of 1.95-2.

27.

8. A novel TOPCon battery according to claim 1, characterized in that, The passivation contact structure includes a tunneling oxide layer, a doped polysilicon layer, and a heavily doped polysilicon layer sequentially disposed on the back side of the silicon wafer. The heavily doped polysilicon is disposed on a patterned mask area on the back side of the doped polysilicon layer, and the electrode contact area on the back side of the heavily doped polysilicon has an ohmic contact with the first finger electrode. The doped polycrystalline silicon layer is an N+ polycrystalline silicon layer with a thickness of 110-130 nm; the heavily doped polycrystalline silicon is N++ polycrystalline silicon.

9. A novel TOPCon battery according to claim 1, characterized in that, The silicon wafer is a texturized silicon wafer, which reduces weight by 0.3-0.7g and has a reflectivity of 9-13%; the back of the texturized silicon wafer is a polished surface, which reduces weight by 0.2-0.5g and has a reflectivity of 35-60%.

10. A novel solar cell module, characterized in that, It includes a novel TOPCon battery as described in any one of claims 1-9.

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