A back-contact battery heat-prevention structure
By introducing gaps between the doped layers of the back contact cell, an open conductive channel structure is formed, which solves the problems of leakage and hot spot effect in the back contact cell, and achieves higher optical performance and lower leakage loss.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HENGDIAN GRP DMEGC MAGNETICS CO LTD
- Filing Date
- 2025-04-28
- Publication Date
- 2026-05-26
AI Technical Summary
Existing back-contact battery heat-prevention structures suffer from excessive leakage current loss and excessive localized overheating.
Gap is introduced between the doped layers of the back contact cell to form an open conductive channel structure. The width of the gap is optimized to avoid leakage risk and reduce parasitic absorption. Polished or pyramidal textured surfaces are used to improve optical performance.
It effectively reduces the risk of hot spot effect at the module end, reduces leakage current loss, and improves the optical performance of photovoltaic modules.
Smart Images
Figure CN224290517U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the photovoltaic field, and in particular to a back-contact battery heat-preventing structure. Background Technology
[0002] Back-contact solar cells are a technology that places both the positive and negative metal contacts of a solar cell on the back of the cell. This unobstructed front structure increases the effective light-receiving area of the module, improving its conversion efficiency. Back-contact solar cell technology has attracted significant attention in the photovoltaic industry due to its high efficiency and aesthetically pleasing front appearance.
[0003] From the perspective of the back contact cell, a cell typically consists of two doped semiconductor layers with opposite conductivity types, arranged in an interdigitated pattern and separated by a gap to suppress forward leakage. This allows the back contact cell to achieve high photoelectric conversion efficiency in the forward voltage region. To separate the two doped semiconductor layers with opposite conductivity types, existing technologies typically create a groove between them, with the bottom of the groove being a semiconductor substrate. However, in practical applications, when the surface of a photovoltaic module made using a back contact cell is covered by obstructions such as leaves, dust, or snow, it can cause hot spots, affecting the module's performance.
[0004] A common hot spot prevention structure for back-contact batteries (patents CN 118825109 A, CN 118472069 B): The thickness of the first doped semiconductor layer in the first region and the thickness of the second doped semiconductor layer in the second region are both greater than the thickness of the conductive channel, meaning there is an empty area above the conductive channel. This empty area serves as insulation, preventing leakage and thus controlling leakage. Furthermore, the conductive channel, with a thickness smaller than the thickness of the first doped semiconductor layer in the first region and the second doped semiconductor layer in the second region, allows current to be transmitted through the first doped semiconductor layer, the conductive channel, and the second doped semiconductor layer when the back-contact battery is blocked, ensuring normal operation of the battery. At this time, the conductive channel can not only reduce the reverse voltage across the back contact battery and effectively reduce the hot spot effect of the back contact battery, but also prevent the shaded back contact battery from becoming a load that consumes the energy generated by other illuminated battery cells, further reducing the risk of hot spots. When the conductive channel includes a co-doped semiconductor layer, the higher doping concentration and lower resistance of the co-doped semiconductor layer facilitates current flow and makes it easier to achieve conduction, ensuring the hot spot prevention effect.
[0005] However, most of the existing back-contact battery heat-prevention structures suffer from excessive leakage current loss and excessive localized overheating. Utility Model Content
[0006] To address the aforementioned technical problems, this invention provides a back-contact battery anti-hotspot structure. This back-contact battery anti-hotspot structure not only reduces the risk of hotspot effects at the module end but also effectively reduces leakage current loss.
[0007] The specific technical solution of this utility model includes:
[0008] In a first aspect, a back-contact battery heat-prevention structure is provided, comprising:
[0009] A silicon substrate has alternating first and second doped regions on its back side, with an isolation region between the first and second doped regions.
[0010] The first doped layer is disposed on the first doped region;
[0011] The second doped layer is disposed on the second doped region;
[0012] At least one first extended doped layer is disposed on the isolation region, connected to the first doped layer, extending toward the second doped layer, and a gap A is provided between it and the second doped layer;
[0013] A conductive channel is disposed at the bottom of the first doped layer, the second doped layer, the first extended doped layer, and the gap A.
[0014] In the above-mentioned back contact battery anti-hot spot structure of this utility model, the first extended doped layer and the second doped layer are disconnected through gap A (the conventional anti-hot spot structure is connected and continuous, that is, without gap, and the extended first / second doped layer is directly connected to the second / first doped layer on the opposite side); wherein the first diffusion layer and the second diffusion layer together form a conductive channel, which is located inside the silicon substrate (formed by boron / phosphorus atoms diffusing into the silicon substrate and diffusing to the surrounding area). This design can avoid the generation of larger conduction leakage.
[0015] In one embodiment, the conductive channel is formed by connecting a first diffusion layer and a second diffusion layer; a first diffusion layer is provided at the bottom of the first doped layer and the first extended doped layer; a second diffusion layer is provided at the bottom of the second doped layer; and a first diffusion layer and / or a second diffusion layer is provided at the bottom of the gap A.
[0016] In one embodiment, the back contact battery heat spot protection structure further includes at least one second extended doped layer disposed on the isolation region, connected to the second doped layer, extending towards the first doped layer and having a gap B between it and the first doped layer; a second diffusion layer is disposed at the bottom of the second extended doped layer; and a first diffusion layer and / or a second diffusion layer are disposed at the bottom of the gap B.
[0017] Based on the design of the first extended doped layer, this utility model further designs a second extended doped layer, which can achieve similar technical effects as the first extended doped layer.
[0018] In one implementation, the width of gap A and / or gap B is 1 / 10 to 4 / 5 of the total width of the isolation zone.
[0019] This invention optimizes the width of the gap (i.e., the lateral dimension, the distance between the first / second extended doped layer and the opposite second / first doped layer, respectively). If the lateral dimension is too small, the risk of leakage will be too high; conversely, if the lateral dimension is too large, conduction cannot be formed.
[0020] In one implementation, the gap A and / or gap B are polished surfaces or pyramidal textured surfaces.
[0021] By using gaps (polished or pyramidal textured surfaces) to disconnect the first / second extended doped layer from the second / first doped layer, this design reduces parasitic absorption and, compared to conventional hot spot prevention designs, is beneficial for achieving higher optical performance.
[0022] In one implementation, the surface of the non-extended doped layer of the isolation region, the area containing non-gap A and / or non-gap B, is a pyramidal textured surface.
[0023] In one embodiment, a tunneling oxide layer is provided between the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer and the conductive channel.
[0024] Secondly, another back-contact battery heat-spot protection structure is provided, which includes:
[0025] A silicon substrate has alternating first and second doped regions on its back side, with an isolation region between the first and second doped regions.
[0026] The first doped layer is disposed on the first doped region;
[0027] The second doped layer is disposed on the second doped region;
[0028] At least one first extended doped layer is disposed on the isolation region, connected to the first doped layer, extending toward the second doped layer but not in contact with the second doped layer;
[0029] At least one second extended doped layer is disposed on the isolation region, connected to the second doped layer, extending towards the first doped layer but not in contact with the first doped layer; a gap C is provided between the first extended doped layer and the second extended doped layer.
[0030] A conductive channel is disposed at the bottom of the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer, and the gap C.
[0031] In the above-mentioned hot spot prevention structure, a gap C is designed between the first extended doped layer and the second extended doped layer, which can achieve a similar technical effect as gaps A and B.
[0032] In one embodiment, the conductive channel is formed by connecting a first diffusion layer and a second diffusion layer; a first diffusion layer is provided at the bottom of the first doped layer and the first extended doped layer, and a second diffusion layer is provided at the bottom of the second doped layer and the first extended doped layer; a first diffusion layer and / or a second diffusion layer is provided at the bottom of the gap C.
[0033] In one implementation, the width of the gap C is 1 / 10 to 4 / 5 of the total width of the isolation zone.
[0034] This invention optimizes the width of the gap (i.e., the lateral dimension, the distance between the first / second extended doped layer and the opposite second / first doped layer, respectively). If the lateral dimension is too small, the risk of leakage will be too high; conversely, if the lateral dimension is too large, conduction cannot be formed.
[0035] In one implementation, the gap C is a polished surface or a pyramidal velvet surface.
[0036] By using gaps (polished or pyramidal textured surfaces) to disconnect the first / second extended doped layer from the second / first doped layer, this design reduces parasitic absorption and, compared to conventional hot spot prevention designs, is beneficial for achieving higher optical performance.
[0037] In one implementation, the surface of the non-first extended doped layer, the non-second extended doped layer, and the region where the gap C is located in the isolation region is a pyramidal textured surface.
[0038] In one embodiment, a tunneling oxide layer is provided between the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer and the conductive channel.
[0039] Thirdly, a back contact battery is provided, characterized in that it includes the aforementioned back contact battery anti-heat spot structure.
[0040] In one embodiment, electrodes are provided on the surfaces of the first doped layer and the second doped layer.
[0041] Compared with the prior art, the beneficial effects of this utility model are:
[0042] (1) This utility model provides a variety of different back contact battery anti-hot spot structures. Their common feature is that the first / second extended doped layer is disconnected from the second / first doped layer through a gap (the conventional anti-hot spot structure is connected and continuous, that is, without gap, the extended first / second doped layer is directly connected to the opposite second / first doped layer); wherein the first diffusion layer and the second diffusion layer together form a conductive channel, which is located inside the silicon substrate (formed by boron / phosphorus atoms diffusing into the silicon substrate and diffusing to the surrounding area). This design can avoid the generation of larger conduction leakage.
[0043] (2) The present invention optimizes the lateral dimension of the gap. If the lateral dimension is too small, the risk of leakage will be too high. Conversely, if the lateral dimension is too large, it will be impossible to form a conductor.
[0044] (3) The present invention disconnects the first / second extended doped layer from the second / first doped layer through gaps (polished surface or pyramid textured surface). This design can reduce parasitic absorption and is more conducive to obtaining higher optical performance compared with conventional hot spot protection design. Attached Figure Description
[0045] Figure 1 This is a cross-sectional schematic diagram of the heat-prevention structure of the back contact battery in Example 1.
[0046] Figure 2 for Figure 1 Top view.
[0047] Figure 3 for Figure 1 A magnified view of a portion of the central isolation zone.
[0048] Figure 4 This is a cross-sectional schematic diagram of the heat-prevention structure of the back contact battery in Example 3.
[0049] Figure 5 for Figure 4 Top view.
[0050] Figure 6 This is a top view of the heat-resistant structure of the back contact battery in Example 5.
[0051] Figure 7 This is a top view of the heat-resistant structure of the back contact battery in Example 7.
[0052] The attached figures are labeled as follows: silicon substrate 1, tunneling oxide layer 2, second doped layer 3, first doped layer 4, pyramid textured surface 5, electrode 6, first diffusion layer 7, second diffusion layer 8, first extended doped layer 9, second extended doped layer 10, gap A 11, gap B 12, gap C 13, first doped region 14, second doped region 15, isolation region 16, conductive channel 17. Detailed Implementation
[0053] The present invention will be further described below with reference to the embodiments.
[0054] General Implementation Examples
[0055] A back-contact battery heat-prevention structure includes:
[0056] A silicon substrate has alternating first and second doped regions on its back side, with an isolation region between the first and second doped regions.
[0057] The first doped layer is disposed on the first doped region;
[0058] The second doped layer is disposed on the second doped region;
[0059] At least one first extended doped layer is disposed on the isolation region, connected to the first doped layer, extending toward the second doped layer, and a gap A is provided between it and the second doped layer;
[0060] A conductive channel is disposed at the bottom of the first doped layer, the second doped layer, the first extended doped layer, and the gap A.
[0061] In one embodiment, the conductive channel is formed by connecting a first diffusion layer and a second diffusion layer; a first diffusion layer is provided at the bottom of the first doped layer and the first extended doped layer; a second diffusion layer is provided at the bottom of the second doped layer; and a first diffusion layer and / or a second diffusion layer is provided at the bottom of the gap A.
[0062] In one embodiment, the back contact battery heat spot protection structure further includes at least one second extended doped layer disposed on the isolation region, connected to the second doped layer, extending towards the first doped layer and having a gap B between it and the first doped layer; a second diffusion layer is disposed at the bottom of the second extended doped layer; and a first diffusion layer and / or a second diffusion layer are disposed at the bottom of the gap B.
[0063] In one implementation, the width of gap A and / or gap B is 1 / 10 to 4 / 5 of the total width of the isolation zone.
[0064] In one implementation, the gap A and / or gap B are polished surfaces or pyramidal textured surfaces.
[0065] In one implementation, the surface of the non-extended doped layer of the isolation region, the area containing non-gap A and / or non-gap B, is a pyramidal textured surface.
[0066] In one embodiment, a tunneling oxide layer is provided between the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer and the conductive channel.
[0067] Another back-contact battery heat-spot protection structure includes:
[0068] A silicon substrate has alternating first and second doped regions on its back side, with an isolation region between the first and second doped regions.
[0069] The first doped layer is disposed on the first doped region;
[0070] The second doped layer is disposed on the second doped region;
[0071] At least one first extended doped layer is disposed on the isolation region, connected to the first doped layer, extending toward the second doped layer but not in contact with the second doped layer;
[0072] At least one second extended doped layer is disposed on the isolation region, connected to the second doped layer, extending towards the first doped layer but not in contact with the first doped layer; a gap C is provided between the first extended doped layer and the second extended doped layer.
[0073] A conductive channel is disposed at the bottom of the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer, and the gap C.
[0074] In one embodiment, the conductive channel is formed by connecting a first diffusion layer and a second diffusion layer; a first diffusion layer is provided at the bottom of the first doped layer and the first extended doped layer, and a second diffusion layer is provided at the bottom of the second doped layer and the first extended doped layer; a first diffusion layer and / or a second diffusion layer is provided at the bottom of the gap C.
[0075] In one implementation, the width of the gap C is 1 / 10 to 4 / 5 of the total width of the isolation zone.
[0076] In one implementation, the gap C is a polished surface or a pyramidal velvet surface.
[0077] In one implementation, the surface of the non-first extended doped layer, the non-second extended doped layer, and the region where the gap C is located in the isolation region is a pyramidal textured surface.
[0078] In one embodiment, a tunneling oxide layer is provided between the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer and the conductive channel.
[0079] A back contact battery, characterized in that it contains the above-mentioned back contact battery heat spot prevention structure.
[0080] In one embodiment, electrodes are provided on the surfaces of the first doped layer and the second doped layer. Specific Implementation
[0082] Example 1
[0083] A back-contact battery heat-spot protection structure, such as Figure 1 and Figure 2As shown (in this embodiment, the first doped region 14 is a p-region, the second doped region 15 is an n-region, the first doped layer 4 is a boron doped layer, the second doped layer 3 is a phosphorus doped layer, the first diffusion layer 7 is a boron diffusion layer, the second diffusion layer 8 is a phosphorus diffusion layer, and the first extended doped layer 9 is an extended boron doped layer), it includes:
[0084] A silicon substrate 1 has alternating p-regions and n-regions on its back side, with an isolation region 16 between the p-regions and n-regions;
[0085] The surface of the p-region is sequentially provided with a tunneling oxide layer 2, a boron doped layer, and an electrode 6;
[0086] The surface of the n-region is sequentially provided with a tunneling oxide layer 2, a phosphorus doped layer, and an electrode 6.
[0087] Specifically, the surface of the isolation region has an extended boron-doped layer that connects to the boron-doped layer and extends towards the phosphorus-doped layer. A gap A 11 is provided between the extended boron-doped layer and the phosphorus-doped layer. This gap A is a polished surface (its lateral width is 1 / 2 of the total width of the isolation region). For example... Figure 3 As shown, a boron diffusion layer is provided at the bottom of the tunneling oxide layer in the p-region, and a tunneling oxide layer 2 and a boron diffusion layer are sequentially provided at the bottom of the extended boron doped layer. A boron diffusion layer is provided at the bottom of the polished surface. A phosphorus diffusion layer is provided at the bottom of the tunneling oxide layer in the n-region. The boron diffusion layer and the phosphorus diffusion layer are connected to form a conductive channel 17. The remaining surfaces of the isolation region are all pyramid textured surfaces 5.
[0088] In this embodiment, the extended boron-doped layer and the phosphorus-doped layer are disconnected by gap A (conventional hot spot prevention structures are continuous, i.e., without gaps, with the extended boron-doped layer directly connected to the opposite phosphorus-doped layer); the boron and phosphorus diffusion layers together form a conductive channel located inside the silicon substrate (formed by boron / phosphorus atoms diffusing into the silicon substrate and spreading outwards). This design avoids larger conduction leakage. Furthermore, disconnecting the extended boron-doped layer and the phosphorus-doped layer by gap A also reduces parasitic absorption, which is beneficial for achieving higher optical performance compared to conventional hot spot prevention designs.
[0089] In one embodiment, the alternating distribution of the first doped region and the second doped region can be in a cross-shaped pattern, or in a back-shaped pattern, a ring-shaped pattern, or the like.
[0090] In one embodiment, a boron diffusion layer and a phosphorus diffusion layer may be provided at the bottom of the polished surface. The boron diffusion layer and the phosphorus diffusion layer are connected at the bottom of the polished surface to form a conductive channel. When the back contact battery is blocked, the current can be transmitted through the conductive channel.
[0091] Example 2
[0092] The difference between Example 2 and Example 1 is that the gap A 11 in Example 2 is a pyramid velvet surface, that is, the polished surface is replaced with a pyramid velvet surface.
[0093] The technical effects of Example 2 are similar to those of Example 1.
[0094] Example 3
[0095] A back-contact battery heat-spot protection structure, such as Figure 4 and Figure 5 As shown (in this embodiment, the first doped region 14 is an n-region, the second doped region 15 is a p-region, the second doped layer 4 is a boron doped layer, the first doped layer 3 is a phosphorus doped layer, the second diffusion layer 7 is a boron diffusion layer, the first diffusion layer 8 is a phosphorus diffusion layer, and the first extended doped layer 9 is an extended phosphorus doped layer), it includes:
[0096] A silicon substrate 1 has p-regions and n-regions arranged alternately in an interdigitated pattern on the back side of the silicon substrate, with an isolation region 16 between the p-regions and n-regions;
[0097] The surface of the p-region is sequentially provided with a tunneling oxide layer 2, a boron doped layer, and an electrode 6;
[0098] The surface of the n-region is sequentially provided with a tunneling oxide layer 2, a phosphorus doped layer, and an electrode 6.
[0099] Specifically, the surface of the isolation region has an extended phosphorus-doped layer connected to the phosphorus-doped layer and extending towards the boron-doped layer. A gap A 11 is provided between the extended phosphorus-doped layer and the boron-doped layer. This gap A is a polished surface (its lateral width is 1 / 2 of the total width of the isolation region). A phosphorus diffusion layer is provided at the bottom of the tunneling oxide layer in the n-region. A tunneling oxide layer 2 and a phosphorus diffusion layer are sequentially provided at the bottom of the extended phosphorus-doped layer; a phosphorus diffusion layer is provided at the bottom of the polished surface; a boron diffusion layer is provided at the bottom of the tunneling oxide layer in the p-region. The connection between the boron diffusion layer and the phosphorus diffusion layer forms a conductive channel 17. The remaining surfaces of the isolation region are all pyramidal textured surfaces 5.
[0100] In this embodiment, the extended phosphorus-doped layer and the boron-doped layer are disconnected by gap A. The boron and phosphorus diffusion layers together form a conductive channel located inside the silicon substrate (formed by boron / phosphorus atoms diffusing into the silicon substrate and outwards). This design avoids larger conduction leakage. Furthermore, disconnecting the extended phosphorus-doped layer and the boron-doped layer by gap A also reduces parasitic absorption, which is beneficial for achieving higher optical performance compared to conventional hotspot prevention designs.
[0101] Example 4
[0102] The difference between Example 3 and Example 1 is that the gap A 11 in Example 4 is a pyramid velvet surface, that is, the polished surface is replaced with a pyramid velvet surface.
[0103] The technical effects of Example 4 are similar to those of Example 3.
[0104] Example 5
[0105] A back-contact battery heat-spot protection structure, such as Figure 6 As shown (in this embodiment, the first doped region 14 is a p-region, the second doped region 15 is an n-region, the first doped layer 4 is a boron doped layer, the second doped layer 3 is a phosphorus doped layer, the first diffusion layer 7 is a boron diffusion layer, the second diffusion layer 8 is a phosphorus diffusion layer, the first extended doped layer 9 is an extended boron doped layer, and the second extended doped layer 10 is an extended phosphorus doped layer), it includes:
[0106] A silicon substrate 1 has p-regions and n-regions arranged in an interdigitated pattern on the back side of the silicon substrate, with an isolation region 16 between the p-regions and the n-regions;
[0107] The surface of the p-region is sequentially provided with a tunneling oxide layer 2, a boron doped layer, and an electrode 6;
[0108] The surface of the n-region is sequentially provided with a tunneling oxide layer 2, a phosphorus doped layer, and an electrode 6.
[0109] Specifically, the surface of the isolation region has an extended boron-doped layer connected to the boron-doped layer and extending towards the phosphorus-doped layer. A gap A11 is provided between the extended boron-doped layer and the phosphorus-doped layer. This gap A is a polished surface (the width of which is 1 / 2 of the total width of the isolation region). A boron diffusion layer is provided at the bottom of the tunneling oxide layer in the p-region. A tunneling oxide layer 2 and a boron diffusion layer are sequentially provided at the bottom of the extended boron-doped layer. A boron diffusion layer is provided at the bottom of the polished surface. A phosphorus diffusion layer is provided at the bottom of the tunneling oxide layer in the n-region.
[0110] The surface of the isolation region also has an extended phosphorus-doped layer that connects to the phosphorus-doped layer and extends towards the boron-doped layer. A gap B12 is provided between the extended phosphorus-doped layer and the boron-doped layer. This gap B is a polished surface (the width of which is 1 / 2 of the total width of the isolation region). A phosphorus diffusion layer is provided at the bottom of the tunneling oxide layer in the n-region. A tunneling oxide layer 2 and a phosphorus diffusion layer are sequentially provided at the bottom of the extended phosphorus-doped layer. A phosphorus diffusion layer is provided at the bottom of the polished surface. A boron diffusion layer is provided at the bottom of the tunneling oxide layer in the p-region.
[0111] The above-mentioned boron diffusion layer and phosphorus diffusion layer are connected to form a conductive channel 17.
[0112] The remaining surfaces of the isolation zone are all pyramid-patterned velvet.
[0113] In this embodiment, gaps A and B disconnect the extended boron / phosphorus doped layer from the phosphorus / boron doped layer, respectively. The boron and phosphorus diffusion layers together form a conductive channel located within the silicon substrate (formed by boron / phosphorus atoms diffusing into the silicon substrate and outwards). This design prevents larger leakage currents. Furthermore, disconnecting the extended boron / phosphorus doped layer from the phosphorus / boron doped layer via gaps A and B reduces parasitic absorption, resulting in higher optical performance compared to conventional hotspot prevention designs.
[0114] Example 6
[0115] The difference between Example 6 and Example 5 is that gaps A 11 and B 12 in Example 6 are both pyramid velvet surfaces, that is, the polished surface is replaced with a pyramid velvet surface.
[0116] The technical effects of Example 6 are similar to those of Example 5.
[0117] Example 7
[0118] A back-contact battery heat-spot protection structure, such as Figure 7 As shown (in this embodiment, the first doped region 14 is a p-region, the second doped region 15 is an n-region, the first doped layer 4 is a boron doped layer, the second doped layer 3 is a phosphorus doped layer, the first diffusion layer 7 is a boron diffusion layer, the second diffusion layer 8 is a phosphorus diffusion layer, the first extended doped layer 9 is an extended boron doped layer, and the second extended doped layer 10 is an extended phosphorus doped layer), it includes:
[0119] A silicon substrate 1 has p-regions and n-regions arranged alternately in an interdigitated pattern on the back side of the silicon substrate, with an isolation region 16 between the p-regions and n-regions;
[0120] The surface of the p-region is sequentially provided with a tunneling oxide layer 2, a boron doped layer, and an electrode 6;
[0121] The surface of the n-region is sequentially provided with a tunneling oxide layer 2, a phosphorus doped layer, and an electrode 6.
[0122] Specifically, the surface of the isolation region is provided with an extended phosphorus doped layer (not in contact with the boron doped layer) connected to the phosphorus doped layer and extending towards the phosphorus doped layer, and an extended boron doped layer (not in contact with the phosphorus doped layer) connected to the boron doped layer and extending towards the phosphorus doped layer. A gap C13 is provided between adjacent extended phosphorus doped layers and extended boron doped layers. The gap C is a polished surface (the width of which is 1 / 2 of the total width of the isolation region).
[0123] A boron diffusion layer is provided at the bottom of the tunneling oxide layer in the p region, a phosphorus diffusion layer is provided at the bottom of the tunneling oxide layer in the n region, and a tunneling oxide layer 2 and a boron diffusion layer are sequentially provided at the bottom of the extended boron doped layer; a tunneling oxide layer 2 and a phosphorus diffusion layer are sequentially provided at the bottom of the extended phosphorus doped layer; a boron diffusion layer is provided at the bottom of the polished surface; the boron diffusion layer and the phosphorus diffusion layer are connected to form a conductive channel 17.
[0124] The remaining surfaces of the isolation zone are all pyramid-patterned velvet.
[0125] The technical effects of Example 7 are similar to those of Example 5.
[0126] Example 8
[0127] The difference between Example 8 and Example 7 is that the gap C 13 in Example 8 is a pyramid velvet surface, that is, the polished surface is replaced with a pyramid velvet surface.
[0128] The technical effects of Example 8 are similar to those of Example 5.
[0129] Example 9
[0130] A back-contact battery heat-spot prevention structure (in this embodiment, the first doped region 14 is a p-region, the second doped region 15 is an n-region, the first doped layer 4 is a boron-doped layer, the second doped layer 3 is a phosphorus-doped layer, the first diffusion layer 7 is a boron diffusion layer, the second diffusion layer 8 is a phosphorus diffusion layer, the first extended doped layer 9 is an extended boron-doped layer, and the second extended doped layer 10 is an extended phosphorus-doped layer), comprising:
[0131] A silicon substrate 1 has p-regions (i.e., the first doped region) and n-regions (i.e., the second doped region) distributed in an interdigitated pattern on the back side of the silicon substrate, and an isolation region 16 is formed between the p-regions and the n-regions;
[0132] The surface of the p-region is sequentially provided with a tunneling oxide layer 2, a boron doped layer, and an electrode 6;
[0133] The surface of the n-region is sequentially provided with a tunneling oxide layer 2, a phosphorus doped layer, and an electrode 6.
[0134] Specifically, the surface of the isolation region is provided with an extended phosphorus doped layer connected to the phosphorus doped layer and extending into the boron doped layer, and an extended boron doped layer connected to the boron doped layer and extending into the phosphorus doped layer. A gap C13 is provided between adjacent extended phosphorus doped layers and extended boron doped layers. The gap C is a polished surface (the width of which is 1 / 2 of the total width of the isolation region).
[0135] A boron diffusion layer is provided at the bottom of the tunneling oxide layer in the p-region, a phosphorus diffusion layer is provided at the bottom of the tunneling oxide layer in the n-region, and a tunneling oxide layer 2 and a boron diffusion layer are sequentially provided at the bottom of the extended boron doped layer; a tunneling oxide layer 2 and a phosphorus diffusion layer are sequentially provided at the bottom of the extended phosphorus doped layer; and a phosphorus diffusion layer is provided at the bottom of the polished surface.
[0136] The above-mentioned boron diffusion layer and phosphorus diffusion layer are connected to form a conductive channel 17.
[0137] The remaining surfaces of the isolation zone are all pyramid-patterned velvet.
[0138] The technical effect of Example 9 is similar to that of Example 5.
[0139] Example 10
[0140] The difference between Example 10 and Example 9 is that the gap C 13 in Example 10 is a pyramid velvet surface, that is, the polished surface is replaced with a pyramid velvet surface.
[0141] The technical effects of Example 10 are similar to those of Example 5.
[0142] In summary, this utility model provides a variety of different back-contact battery heat-prevention structures. Their common feature is that the first doped layer and the second doped layer are disconnected through a gap. The first diffusion layer and the second diffusion layer together form a conductive channel, which is located inside the silicon substrate (formed by boron / phosphorus atoms diffusing into the silicon substrate and spreading outwards. This design can avoid the generation of larger conduction leakage current).
[0143] Unless otherwise specified, the raw materials and equipment used in this utility model are all commonly used in the field; unless otherwise specified, the methods used in this utility model are all conventional methods in the field.
[0144] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the present utility model. Any simple modifications, alterations, or equivalent transformations made to the above embodiments based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model.
Claims
1. A back contact cell hot spot prevention structure, characterized by include: A silicon substrate has alternating first and second doped regions on its back side, with an isolation region between the first and second doped regions. The first doped layer is disposed on the first doped region; The second doped layer is disposed on the second doped region; At least one first extended doped layer is disposed on the isolation region, connected to the first doped layer, extending toward the second doped layer, and a gap A is provided between it and the second doped layer; A conductive channel is disposed at the bottom of the first doped layer, the second doped layer, the first extended doped layer, and the gap A.
2. The back contact battery heat-prevention structure according to claim 1, characterized in that: The conductive channel is formed by connecting a first diffusion layer and a second diffusion layer; A first diffusion layer is provided at the bottom of the first doped layer and the first extended doped layer; A second diffusion layer is provided at the bottom of the second doped layer; The bottom of the gap A is provided with a first diffusion layer and / or a second diffusion layer.
3. The back contact cell anti-hot spot structure of claim 2, wherein: It also includes at least one second extended doped layer, disposed on the isolation region, connected to the second doped layer, extending toward the first doped layer and having a gap B between it and the first doped layer; A second diffusion layer is provided at the bottom of the second extended doped layer; The bottom of the gap B is provided with a first diffusion layer and / or a second diffusion layer.
4. The back contact battery heat-prevention structure according to any one of claims 1-3, characterized in that: The width of gap A and / or gap B is 1 / 10 to 4 / 5 of the total width of the isolation zone; and / or The gap A and / or gap B are polished surfaces or pyramidal textured surfaces; and / or The surface of the non-extended doped layer in the isolation region, where non-gap A and / or non-gap B are located, is a pyramidal textured surface.
5. The back contact cell anti-hot spot structure of claim 3, wherein: A tunneling oxide layer is provided between the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer and the conductive channel.
6. A back contact cell anti-hot spot structure, characterized by include: A silicon substrate with alternating first and second doped regions, and an isolation region on the back side; The first doped layer is disposed on the first doped region; The second doped layer is disposed on the second doped region; At least one first extended doped layer is disposed on the isolation region, connected to the first doped layer and not in contact with the second doped layer; At least one second extended doped layer is disposed on the isolation region, connected to the second doped layer but not in contact with the first doped layer; a gap C is provided between the first extended doped layer and the second extended doped layer. A conductive channel is disposed at the bottom of the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer, and the gap C.
7. The back contact battery heat-prevention structure according to claim 6, characterized in that: The conductive channel is formed by connecting a first diffusion layer and a second diffusion layer; A first diffusion layer is provided at the bottom of the first doped layer and the first extended doped layer. A second diffusion layer is provided at the bottom of the second doped layer and the first extended doped layer; The bottom of the gap C is provided with a first diffusion layer and / or a second diffusion layer.
8. The back contact battery heat-prevention structure according to claim 6 or 7, characterized in that: The width of the gap C is 1 / 10 to 4 / 5 of the total width of the isolation zone; and / or The gap C is a polished surface or a pyramidal textured surface; and / or The surface of the non-first extended doped layer, the non-second extended doped layer, and the region where the gap C is located in the isolation region is a pyramidal textured surface.
9. The back contact battery heat-prevention structure according to claim 6 or 7, characterized in that: A tunneling oxide layer is provided between the first doped layer, the second doped layer, the first extended doped layer, the second extended doped layer and the conductive channel.
10. A back contact cell characterized by: The back contact battery includes the heat-preventing structure as described in any one of claims 1-9.