Photovoltaic cell, module and system

Abstract

The present disclosure relates to the technical field of solar cells, and specifically disclosed are a photovoltaic cell, module and system. The cell comprises a substrate, a doped layer disposed on a second surface of the substrate, and a TCO layer. The TCO layer comprises a main body portion and a micro leakage channel portion, wherein the main body portion is arranged on the side of the doped layer facing away from the substrate, and the micro leakage channel portion extends from at least part of an edge of the main body portion to the outer side of a side surface of the substrate.

Description

Photovoltaic cells, modules and systems

[0001] Priority information

[0002] This disclosure claims priority and benefits to patent application No. 202510378880.4, filed with the China National Intellectual Property Administration on March 27, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of solar cell technology, and in particular to a back-contact cell, a cell module, and a photovoltaic system. Background Technology

[0004] In the current photovoltaic technology field, back-contact solar cells, as a highly efficient and widely used solar cell structure, have always been a focus of research in terms of performance and stability. However, in actual operation, back-contact solar cells are often affected by the hot spot effect, especially in the edge areas of the cell, where this phenomenon is more pronounced. Due to the hot spot effect, the cell is prone to localized heating. This heating not only reduces the cell's conversion efficiency but may also cause localized overheating, thereby damaging the cell structure and even posing safety hazards.

[0005] Currently, to effectively mitigate the negative impact of hot spot effects on back-contact batteries, the main improvement approach focuses on modifying the structure of the doped layer. Specifically, this involves constructing specific structures between different doped regions to form micro-leakage channels, thereby mitigating the hot spot effect. These micro-leakage channels provide a low-impedance discharge path for the battery's internal charge, preventing localized overheating caused by charge accumulation. However, this design is not without limitations. Firstly, when using a doped layer as the micro-leakage channel structure, the inherent properties of semiconductor materials lead to significant selectivity in charge transport. If a pn junction is formed, its unidirectional conductivity prevents free discharge of charge under specific voltage biases, thus failing to achieve the intended function of the micro-leakage channel and hindering its effective formation. Secondly, existing improvement approaches often neglect the hot spot effect at the battery's edge regions, failing to specifically improve the edge regions' resistance to hot spot effects. Consequently, the reliability and safety of the battery in dealing with hot spot effects are significantly compromised, making it impossible to reliably guarantee normal operation and safe use. Summary of the Invention

[0006] The purpose of this disclosure is to provide a back contact battery, battery module and photovoltaic system in light of the existing technology.

[0007] The back-contact battery disclosed herein can reduce the hot spot effect, avoid local overheating caused by charge accumulation, and improve the overall reliability and safety of the battery.

[0008] To achieve the above objectives, the present disclosure adopts the following technical solution:

[0009] First, this disclosure provides a back-contact battery, comprising: a substrate having a first surface, a second surface and a plurality of side surfaces, the first surface and the second surface being disposed opposite to each other, and the side surfaces being connected to the first surface and the second surface respectively; a doped layer disposed on the second surface; and a TCO layer comprising a main body portion and a micro-leakage channel portion, the main body portion being disposed on the side of the doped layer facing away from the substrate, and the micro-leakage channel portion extending from at least a portion of the edge of the main body portion along a first direction to the outer side of the side surface, the first direction being the direction from the second surface toward the first surface.

[0010] In some embodiments, the thickness of the micro-leakage channel decreases along a first direction.

[0011] In some embodiments, the micro leakage channel portion includes a first end and a second end in a first direction, and the second end is the end of the micro leakage channel portion away from the main body portion, wherein the thickness of the first end is H, and the thickness h of the second end is 0 < h ≤ 10%H.

[0012] In some embodiments, H is 70nm to 90nm.

[0013] In some embodiments, a functional layer is further provided on the first surface, and the micro-leakage channel extends to the outside of the sidewall of the functional layer.

[0014] In some embodiments, the functional layer includes one or more of a passivation layer and an antireflection layer.

[0015] In some embodiments, the length of the micro-leakage channel portion along the first direction is L, where L satisfies the following relationship: 0.1×S≤L≤0.85×S.

[0016] In the formula, S is the relative distance in the first direction from the side of the functional layer facing away from the first surface to the end of the micro-leakage channel that is away from the first surface.

[0017] In some embodiments, the main body includes a transverse portion, the surface of which is parallel to the surface of the second surface, and the thickness of the transverse portion is greater than or equal to the thickness of the end of the micro-leakage channel portion away from the first surface.

[0018] In some embodiments, the side includes a first side, a second side, a third side, and a fourth side connected in sequence. The first side and the third side are arranged along a second direction, and the second side and the fourth side are arranged along a third direction. The second direction and the third direction are intersected. The micro leakage channel is located on the outside of at least one of the first side, the second side, the third side, and the fourth side.

[0019] In some embodiments, the second surface has a plurality of first regions and second regions arranged alternately along a second direction. The main body includes a first TCO segment disposed in the first region and a second TCO segment disposed in the second region. The first TCO segment and the second TCO segment extend along a third direction. The doped layer includes a first doped layer and a second doped layer with opposite polarities. At least a portion of the first TCO segment is electrically connected to the first doped layer, and at least a portion of the second TCO segment is electrically connected to the second doped layer.

[0020] In some embodiments, the main body includes a first edge region and a second edge region, the first edge region and the second edge region are respectively located at both ends of the main body in a second direction, and the portion of the main body located on the first edge region and the portion on the first edge region are each independently a first TCO segment or a second TCO segment, and the first edge region is located at one end of the main body near the first side.

[0021] The micro-leakage channel part satisfies at least one of the following:

[0022] The micro leakage channel includes at least one first unit disposed on the first side, and the at least one first unit is connected to the same first TCO segment or the same second TCO segment of the main body located in the first edge region;

[0023] The micro leakage channel includes at least one third unit disposed on the third side, and the at least one third unit is connected to the same first TCO segment or the same second TCO segment of the main body located in the second edge region.

[0024] In some embodiments, the micro-leakage channel portion satisfies at least one of the following:

[0025] The micro leakage current channel includes a second unit disposed on the second side, and the second unit includes at least one of a second unit A connected to the first TCO segment and a second unit B connected to the second TCO segment;

[0026] The micro leakage current channel includes a fourth unit disposed on the fourth side, the fourth unit including at least one of a fourth unit A connected to the first TCO segment and a fourth unit B connected to the second TCO segment.

[0027] In some embodiments, a first doped layer is disposed in a first region, and a second doped layer includes a first segment disposed in the first region and a second segment disposed in the second region;

[0028] The first segment is located on the side of the first doped layer facing away from the substrate, and an insulating protective layer is provided between the first doped layer and the second doped layer. The first segment and the insulating protective layer have a channel. The first TCO segment includes a contact portion located in the channel, which is in contact with the first doped layer. The second segment is in contact with the second TCO segment.

[0029] In some embodiments, the doped layer satisfies at least one of the following:

[0030] A first passivation layer is provided between the first doped layer and the substrate;

[0031] The second doped layer has a second passivation layer on the side facing the substrate. The second passivation layer includes a first portion disposed in the first region and a second portion extending to the second region. The first portion is disposed between the insulating protective layer and the second doped layer.

[0032] Secondly, this disclosure provides a battery assembly including the aforementioned back contact battery.

[0033] Thirdly, this disclosure provides a photovoltaic system including the aforementioned battery module.

[0034] The beneficial effects of this disclosure are as follows:

[0035] The TCO layer in this disclosure includes a main body portion disposed on the side of the doped layer facing away from the substrate and a micro-leakage channel portion extending from the edge of the main body portion along a first direction to the outer side of the side. This forms a micro-leakage path on the sidewall of the battery. Regardless of the polarity of the conductive region where the sidewall of the battery is located, when shading occurs, excess charge can recombine with the substrate charge through the micro-leakage channel portion, thereby reducing the hot spot effect and avoiding local overheating caused by charge accumulation. At the same time, compared with the structure of using a doped layer as the micro-leakage channel, this disclosure can avoid selective charge transport, ensure the reliability and safety of the battery in dealing with the hot spot effect, and effectively increase the anti-hot spot performance of the battery edge region, further improving the overall reliability and safety of the battery. Attached Figure Description

[0036] Figure 1 is a schematic diagram of the edge structure of a back contact battery in a second direction according to an embodiment of the present disclosure.

[0037] Figure 2 is a schematic diagram of another edge structure of a back contact battery in a second direction according to an embodiment of the present disclosure.

[0038] Figure 3 is a schematic diagram of the edge structure of a back contact battery along a third-direction cross-section according to an embodiment of the present disclosure.

[0039] Figure 4 is a schematic diagram of the other edge structure of the back contact battery along a third-direction cross-section according to an embodiment of the present disclosure.

[0040] Figure 5 is a top view of a back contact battery provided according to an embodiment of the present disclosure.

[0041] Figure 6 is a partial structural diagram of the micro leakage channel provided according to an embodiment of the present disclosure when there is a second unit A and a second unit B (with a gap between them).

[0042] Figure 7 is a partial structural diagram of the micro leakage channel provided according to an embodiment of the present disclosure when there is a second unit A and a second unit B (the two are in partial contact).

[0043] Figure 8 is a partial structural diagram of the micro leakage channel provided according to an embodiment of the present disclosure when a third unit A and a second unit B are present (with a gap between them).

[0044] Figure 9 is a partial structural diagram of the micro leakage channel provided according to an embodiment of the present disclosure when a third unit A and a second unit B are present (the two are in partial contact). Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this disclosure, and should not be construed as limiting this disclosure. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this disclosure and are not intended to limit this disclosure.

[0046] In the description of this disclosure, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of the stated features. In the description of this disclosure, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0047] In the description of this disclosure, unless otherwise expressly specified and limited, the term "above" or "below" the second feature may include direct contact between the first and second features, or contact between the first and second features not in direct contact but through another feature between them.

[0048] Referring to Figures 1, 2, and 5, this disclosure provides a back-contact battery, comprising: a substrate 1, a doped layer, and a TCO layer 2. The substrate 1 has a first surface 11, a second surface 12, and a side surface 13. The first surface 11 and the second surface 12 are disposed opposite to each other, and the side surface 13 is connected to the first surface 11 and the second surface 12, respectively. The doped layer 3 is disposed on the second surface 12. The TCO layer 2 includes a main body portion 21 and a micro-leakage channel portion 22. The main body portion 21 is disposed on the side of the doped layer 3 facing away from the substrate 1, and the micro-leakage channel portion 22 extends from at least a portion of the edge of the main body portion 21 along a first direction to the outer side of the side surface 13. The first direction is from the second surface 12 toward the first surface 11.

[0049] Understandably, the substrate 1 has a first surface 11 and a second surface 12 disposed opposite to each other, wherein one is the light-receiving surface (usually referred to as the front surface of the substrate 1) and the other is the back surface (usually referred to as the back surface of the substrate 1), and the sidewalls of the perimeter of the substrate 1 are the side surfaces 13. In this disclosure, the first surface 11 is the light-receiving surface and the second surface 12 is the back surface, wherein the light-receiving surface refers to the surface that receives light, and its surface may also be provided with a passivation layer, an anti-reflection layer, etc., but is not limited thereto. In some embodiments, the light-receiving surface may also be provided with a textured surface. It should be noted that in some embodiments, light incident through the back surface may also be absorbed, thereby generating a photocurrent. Furthermore, in practical applications, the embodiments of this disclosure do not specifically limit the material and conductivity type of the substrate 1. For example, the substrate 1 can be a silicon substrate, such as monocrystalline silicon, microcrystalline silicon, polycrystalline silicon or amorphous silicon, or a germanium silicon substrate, germanium substrate or gallium arsenide substrate, but is not limited thereto, and its conductivity type can be N-type or P-type.

[0050] Understandably, in conventional batteries, the area at the edge of the back of the battery is removed after the transparent conductive layer is deposited. In this disclosure, the edge of the main body 21 of the TCO layer 2 extends to the edge of the second surface 12 and extends along the first direction to the outside of the side 13 to form a micro-leakage channel.

[0051] The TCO layer 2 in this disclosure includes a main body portion 21 disposed on the side of the doped layer 3 facing away from the substrate 1, and a micro-leakage channel portion 22 extending from the edge of the main body portion 21 along a first direction to the outer side of the side 13. This forms a micro-leakage path on the sidewall of the battery. Regardless of the polarity of the conductive region where the sidewall of the battery is located, when shading occurs, excess charge can recombine with the charge in the substrate 1 through the micro-leakage channel portion 22, thereby reducing the hot spot effect and avoiding local overheating caused by charge accumulation. At the same time, compared with using the doped layer 3 as the micro-leakage channel, this disclosure can avoid selective charge transport, ensuring the reliability and safety of the battery when dealing with the hot spot effect, and effectively increasing the anti-hot spot performance of the battery edge area. According to tests, the hot spot effect temperature at the battery edge in this disclosure can be kept below 100°C, further improving the overall reliability and safety of the battery.

[0052] In some embodiments, the TCO layer 2, namely the transparent conductive oxide thin film layer, can be a single-layer material layer or a composite material layer composed of multiple single-layer material layers stacked together. The material of the single-layer material layer can be any one of ITO, IWO, and AZO.

[0053] In some embodiments, at least one of the first TCO segment 211 and the second TCO segment 212 may be a single-layer material layer or a composite TCO material layer composed of multiple layers of material stacked together.

[0054] In one embodiment, the thickness of the micro-leakage channel portion 22 remains relatively constant along the first direction.

[0055] In another embodiment, as shown in FIG1, the thickness of the micro-leakage channel portion 22 decreases along the first direction.

[0056] Understandably, in terms of the regularity of the decreasing trend, the decreasing trend of the thickness of the micro-leakage channel portion 22 can be linear or non-linear; in terms of the continuity of the decreasing trend, the decreasing trend of the thickness of the micro-leakage channel portion 22 can be continuous or discontinuous. For example, the sidewall contour of the side of the micro-leakage channel facing away from the side 13 of the substrate 1 can be an inclined straight line, a stepped shape, or an arc-shaped line, but is not limited to these.

[0057] When the micro-leakage channel 22 is in operation, charge is transferred from the edge of the main body 21 to the micro-leakage channel 22. The thickness of the micro-leakage channel 22 decreases along the first direction. The thicker initial end has higher conductivity, which is conducive to rapid charge transfer. As the thickness gradually decreases, the electric field distribution changes, forming a driving force that is conducive to charge transfer in a specific direction. This helps guide the charge to transfer along the first direction, thereby reducing the hot spot effect and avoiding local overheating caused by charge accumulation. At the same time, the decreasing thickness of the micro-leakage channel 22 is also conducive to reducing the amount of TCO material used, reducing material costs, and facilitating the industrial production of the product.

[0058] In some embodiments, referring to FIG2, the micro-leakage channel portion 22 includes a first end 221 and a second end 222 in a first direction, and the second end 222 is the end of the micro-leakage channel portion 22 away from the main body portion 21. The thickness of the first end 221 is H, and the thickness h of the second end 222 is 0 < h ≤ 10% H. Providing a smaller thickness for the second end 222 helps to reduce costs and facilitates the formation of sufficient driving force for charge transmission in a specific direction.

[0059] In some embodiments, H is 70nm to 90nm. For example, H is 70nm, 72nm, 75nm, 78nm, 80nm, 82nm, 85nm, 88nm or 90nm, but is not limited thereto.

[0060] In some embodiments, as shown in Figures 1 and 2, a functional layer 6 is further provided on the first surface 11, and the micro-leakage channel portion 22 extends to the outside of the sidewall of the functional layer 6.

[0061] In some embodiments, functional layer 6 includes one or more of a passivation layer and an antireflection layer.

[0062] When the functional layer 6 includes a passivation layer and an anti-reflection layer, the anti-reflection layer is disposed on the side of the passivation layer facing away from the substrate 1.

[0063] In some embodiments, referring to FIG2, the length of the micro-leakage channel portion 22 along the first direction is L, wherein 0.1×S≤L≤0.85×S.

[0064] In the formula, S is the relative distance in the first direction from the side of the functional layer 6 facing away from the first surface 11 to the end of the micro-leakage channel portion 22 away from the first surface 11.

[0065] The coverage of the micro leakage channel section 22 should not be too high, otherwise it will easily affect the conversion efficiency. The coverage of the micro leakage channel section 22 should not be too low, otherwise an effective leakage channel cannot be formed. When 0.1×S≤L≤0.85×S, it can have both high conversion efficiency and good anti-hot spot performance, and the overall performance is better.

[0066] In some embodiments, the main body 21 includes a transverse portion, the surface of which is parallel to the surface of the second surface 12, and the thickness of the transverse portion is greater than or equal to the thickness of the end of the micro-leakage channel portion 22 away from the first surface 11. A larger transverse portion results in higher conductivity, which is beneficial for carrier transport during normal battery operation.

[0067] In some embodiments, side 13 includes a first side 131, a second side 132, a third side 133, and a fourth side 134 connected in sequence. The first side 131 and the third side 133 are arranged along a second direction, and the second side 132 and the fourth side 134 are arranged along a third direction. The second direction and the third direction are intersected. The micro leakage channel portion 22 is disposed on the outside of at least one of the first side 131, the second side 132, the third side 133, and the fourth side 134.

[0068] Understandably, the micro leakage channel portion 22 can be provided on any one side 13 or on multiple sides 13, without limitation. Regardless of which side it is located on, the thickness of the micro leakage channel portion 22 can be set to decrease along the first direction, that is, each side is provided with a first end 221 and a second end 222.

[0069] In some embodiments, referring to Figures 1 and 2, the second surface 12 has a plurality of first regions and second regions arranged alternately along a second direction. The main body 21 includes a first TCO segment 211 disposed in the first region and a second TCO segment 212 disposed in the second region. The first TCO segment 211 and the second TCO segment 212 extend along a third direction. The doped layer 3 includes a first doped layer 31 and a second doped layer 32 with opposite polarities. At least a portion of the first TCO segment 211 is electrically connected to the first doped layer 31, and at least a portion of the second TCO segment 212 is electrically connected to the second doped layer 32.

[0070] Understandably, in terms of conductivity type, the polarity of the first doped layer 31 and the polarity of the second doped layer 32 can be the same as or opposite to the polarity of the substrate 1, as long as it is ensured that the polarity of the first doped layer 31 is opposite to the polarity of the second doped layer 32. One of the first doped layer 31 and the second doped layer 32 is made of monocrystalline silicon, polycrystalline silicon, or amorphous silicon doped with group III elements (e.g., B, Ga, or In), and the other is made of monocrystalline silicon, microcrystalline silicon, polycrystalline silicon, or amorphous silicon doped with group V elements (e.g., P, As, Sb).

[0071] Understandably, the first TCO segment 211 and the first doped layer 31 can be electrically connected through direct contact or indirect contact through a conductive material layer. This contact can be a partial or complete contact between the first TCO segment 211 and the first doped layer 31. Similarly, the second TCO segment 212 and the second doped layer 32 can be electrically connected through direct contact or indirect contact through a conductive material layer. This contact can be a partial or complete contact between the second TCO segment 212 and the second doped layer 32.

[0072] In some embodiments, referring to FIG1 and FIG2, the two end regions of the main body 21 located in the second direction are referred to as the first edge region 223 and the second edge region 224. The portion of the main body 21 located on the first edge region 223 and the first edge region 224 are each independently referred to as the first TCO segment 211 or the second TCO segment 212. The first edge region 223 is located at the end of the main body 21 near the first side 131.

[0073] The micro leakage channel section 22 includes a first unit 225 disposed on the first side 131. The first unit 225 is connected to the same first TCO segment 211 or the same second TCO segment 212 of the main body section 21 located in the first edge region 223.

[0074] Understandably, the first unit 225 can be a single unit or multiple units arranged at intervals. When there are multiple first units 225, the multiple first units 225 are connected to the same first TCO segment 211 or the same second TCO segment 212 of the main body 21 located in the first edge region 223.

[0075] In some embodiments, referring to FIG2, the micro leakage channel portion 22 includes a third unit 227 disposed on the third side 133, the third unit 227 being connected to the same first TCO segment 211 or the same second TCO segment 212 of the main body portion 21 located in the second edge region 224.

[0076] Understandably, the third unit 227 can be a single unit or multiple units arranged at intervals. When there are multiple third units 227, the multiple third units 227 are connected to the same first TCO segment 211 or the same second TCO segment 212 of the main body 21 located in the second edge region 224.

[0077] In some embodiments, as shown in Figures 4, 6 and 7, the micro leakage channel portion 22 includes a second unit 226 disposed on the second side 132. The second unit 226 includes at least one of a second unit A226A connected to the first TCO segment 211 and a second unit B226B connected to the second TCO segment 212.

[0078] Understandably, the second unit 226 on the second side 132 may only include the second unit A226A connected to the first TCO segment 211, or it may only include the second unit B226B connected to the second TCO segment 212, or it may include both the second unit A226A and the second unit B226B. When the second unit 226 on the second side 132 includes the second unit A226A and the second unit B226B, there may be a gap between the second unit A226A and the second unit B226B (as shown in Figure 6), or there may be no gap (as shown in Figure 7). When there is no gap between the second unit A226A and the second unit B226B, there is local contact between them, which can improve the anti-hot spot effect. The same applies to the fourth unit 228 below, which will not be described in detail here.

[0079] In some embodiments, referring to Figures 3, 8 and 9, the micro leakage channel portion 22 includes a fourth unit 228 disposed on the fourth side 134. The fourth unit 228 includes at least one of a fourth unit A228A connected to the first TCO segment 211 and a fourth unit B228B connected to the fourth TCO segment.

[0080] In some embodiments, the first doped layer 31 and the second doped layer 32 are arranged alternately along a second direction. In other embodiments, the second doped layer 32 may have a portion of its area stacked on a portion of the first doped layer 31. Referring to Figures 1 and 2, the first doped layer 31 is disposed in the first region, and the second doped layer 32 includes a first segment 321 disposed in the first region and a second segment 322 extending into the second region. The first segment 321 is disposed on the side of the first doped layer 31 facing away from the substrate 1, and an insulating protective layer 4 is provided between the first doped layer 31 and the second doped layer 32. The first segment 321 and the insulating protective layer 4 have channels. The first TCO segment 211 includes a contact portion disposed in the channel, which contacts the first doped layer 31. The second segment 322 contacts the second TCO segment 212.

[0081] In some embodiments, the insulating protective layer 4 may be made of PSG or SiN. x SiO x Any one of them.

[0082] In some embodiments, as shown in FIG1 and FIG2, a first passivation layer 51 is provided between the first doped layer 31 and the substrate 1.

[0083] In some embodiments, as shown in Figures 1 and 2, a second passivation layer 52 is provided on the side of the second doped layer 32 facing the substrate 1. The second passivation layer 52 includes a first portion disposed in the first region and a second portion extending to the second region. The first portion is disposed between the insulating protective layer 4 and the second doped layer 32.

[0084] By setting the first passivation layer 51 and the second passivation layer 52, the passivation effect and carrier transport effect are improved, which is beneficial to improving the conversion efficiency of the battery. For example, the first passivation layer 51 and the second passivation layer 52 can be intrinsic amorphous silicon layers or tunneling oxide layers (such as silicon oxide, titanium oxide, etc.), but are not limited to these.

[0085] Secondly, this disclosure provides a battery assembly including the aforementioned back contact battery.

[0086] Furthermore, this disclosure provides a photovoltaic system including the aforementioned battery module.

[0087] The photovoltaic system includes battery modules, which include the aforementioned solar cells. Multiple battery modules can be connected in series or parallel through a junction box to form a photovoltaic system. This photovoltaic system can be used in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings, but is not limited to these applications.

[0088] The present disclosure will be further explained below with reference to embodiments and comparative examples:

[0089] Example 1

[0090] The back-contact battery includes a substrate, a doped layer, and a TCO layer. The substrate has a first surface, a second surface, and a side surface. The first surface and the second surface are disposed opposite to each other, and the side surface is connected to the first surface and the second surface, respectively. The doped layer is disposed on the second surface. The TCO layer includes a main body and a micro-leakage channel. The main body is disposed on the side of the doped layer facing away from the substrate, and the micro-leakage channel extends from at least a portion of the edge of the main body along a first direction to the outer side of the side surface. The first direction is from the second surface toward the first surface. In this embodiment 1, the thickness of the micro-leakage channel decreases along the first direction.

[0091] Comparative Example 1

[0092] The difference between this embodiment and Embodiment 1 is that Comparative Example 1 does not have a micro-leakage channel.

[0093] Hot spot test

[0094] Hot spot tests were performed on the solar cells prepared in Example 1 and Comparative Example 1 to observe their temperature changes.

[0095] Test results:

[0096] Experimental results show that, compared with Comparative Example 1, the hot spot effect temperature at the edge of the battery in Example 1 of this disclosure can be kept below 100°C, resulting in better hot spot resistance and better battery reliability and stability.

[0097] In the description of this specification, references to terms such as "some embodiments," "exemplary," "example," or "for example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0098] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure in any way. Although this disclosure has been disclosed above with reference to preferred embodiments, it is not intended to limit this disclosure. Any person skilled in the art can make some modifications or alterations to the above-mentioned technical content to create equivalent embodiments without departing from the scope of the technical solution of this disclosure. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this disclosure without departing from the content of the technical solution of this disclosure shall still fall within the scope of this disclosure.

Claims

1. A back-contact battery, wherein, include: The substrate has a first surface, a second surface, and a plurality of side surfaces, wherein the first surface and the second surface are disposed opposite to each other, and the side surfaces are respectively connected to the first surface and the second surface; A doped layer is disposed on the second surface; The TCO layer includes a main body portion and a micro-leakage channel portion. The main body portion is disposed on the side of the doped layer opposite to the substrate. The micro-leakage channel portion extends from at least a portion of the edge of the main body portion along a first direction to the outer side of the side, where the first direction is from the second surface toward the first surface.

2. The back contact battery according to claim 1, wherein, The thickness of the micro-leakage channel decreases along the first direction.

3. The back contact battery according to claim 2, wherein, The micro-leakage channel portion includes a first end and a second end in the first direction, and the second end is the end of the micro-leakage channel portion away from the main body portion, wherein the thickness of the first end is H, and the thickness h of the second end is 0 < h ≤ 10% H.

4. The back contact battery according to claim 3, wherein, H is 70nm~90nm.

5. The back contact battery according to claim 1, wherein, The first surface is further provided with a functional layer, and the micro leakage channel extends to the outside of the sidewall of the functional layer.

6. The back contact battery according to claim 5, wherein, The functional layer includes one or more of a passivation layer and an anti-reflection layer.

7. The back contact battery according to claim 5, wherein, The length of the micro-leakage channel along the first direction is L, and L satisfies the following relationship: 0.1×S≤L≤0.85×S. In the formula, S is the relative distance in the first direction from the side of the functional layer facing away from the first surface to the end of the micro-leakage channel portion away from the first surface.

8. The back contact battery according to claim 1, wherein, The main body includes a transverse portion, the surface of which is parallel to the surface of the second surface, and the thickness of the transverse portion is greater than or equal to the thickness of the end of the micro-leakage channel portion away from the first surface.

9. The back contact battery according to claim 1, wherein, The side surface includes a first side surface, a second side surface, a third side surface, and a fourth side surface connected in sequence. The first side surface and the third side surface are arranged along a second direction, and the second side surface and the fourth side surface are arranged along a third direction. The second direction and the third direction are intersected. The micro leakage current channel is located on the outside of at least one of the first side surface, the second side surface, the third side surface, and the fourth side surface.

10. The back contact battery according to claim 9, wherein, The second surface has a plurality of first regions and second regions that are alternately arranged along the second direction; The main body includes a first TCO segment disposed in the first region and a second TCO segment disposed in the second region, wherein the first TCO segment and the second TCO segment extend along the third direction; The doped layer includes a first doped layer and a second doped layer with opposite polarities. At least a portion of the first TCO segment is electrically connected to the first doped layer, and at least a portion of the second TCO segment is electrically connected to the second doped layer.

11. The back contact battery according to claim 10, wherein, The main body includes a first edge region and a second edge region. The first edge region and the second edge region are respectively located at both ends of the main body in the second direction. The portion of the main body located in the first edge region and on the first edge region are each independently the first TCO segment or the second TCO segment. The first edge region is located at one end of the main body near the first side. The micro-leakage channel section satisfies at least one of the following: The micro leakage channel includes at least one first unit disposed on the first side, and the at least one first unit is connected to the same first TCO segment or the same second TCO segment of the main body located in the first edge region; The micro-leakage channel includes at least one third unit disposed on the third side, and the at least one third unit is connected to the same first TCO segment or the same second TCO segment of the main body located in the second edge region.

12. The back contact battery according to claim 10, wherein, The micro-leakage channel portion satisfies at least one of the following: The micro leakage channel includes a second unit disposed on the second side, the second unit including at least one of a second unit A connected to the first TCO segment and a second unit B connected to the second TCO segment; The micro-leakage channel includes a fourth unit disposed on the fourth side, the fourth unit including at least one of a fourth unit A connected to the first TCO segment and a fourth unit B connected to the second TCO segment.

13. The back contact battery according to claim 10, wherein, The first doped layer is disposed in the first region, and the second doped layer includes a first segment disposed in the first region and a second segment disposed in the second region; The first segment is located on the side of the first doped layer facing away from the substrate, and an insulating protective layer is provided between the first doped layer and the second doped layer. The first segment and the insulating protective layer have a channel. The first TCO segment includes a contact portion located in the channel. The contact portion is in contact with the first doped layer, and the second segment is in contact with the second TCO segment.

14. The back contact battery according to claim 13, wherein, The doped layer satisfies at least one of the following: A first passivation layer is provided between the first doped layer and the substrate; The second doped layer has a second passivation layer on the side facing the substrate. The second passivation layer includes a first portion disposed in the first region and a second portion extending to the second region. The first portion is disposed between the insulating protective layer and the second doped layer.

15. A battery assembly, wherein, Includes the back contact battery according to any one of claims 1 to 14.

16. A photovoltaic system, wherein, Includes the battery assembly as described in claim 15.

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