Radiation-proof solar cell and array
By setting alternating minority and majority carrier selection regions on the front and back of the solar cell, and using a high-resistivity monocrystalline silicon substrate and passivation layer, the problem of performance degradation of crystalline silicon solar cells under space irradiation was solved, and stable output of electrical performance was achieved.
Patent Information
- Application Number
- CN202511236782.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-01
- Publication Date
- 2025-12-09
AI Technical Summary
Existing crystalline silicon solar cells suffer severe performance degradation after being exposed to charged particle radiation in the space environment, especially the minority carrier diffusion length, which decreases sharply, leading to a decline in electrical performance. Existing methods, such as increasing the resistivity of silicon wafers or reducing the thickness of silicon wafers, suffer from high costs or poor reliability.
The solar cell has alternately arranged minority carrier selection regions and majority carrier selection regions on the front and back sides. The captured minority and majority carriers are output through the back and front electrodes to ensure that the current can still be effectively output after irradiation. High-resistivity monocrystalline silicon or intrinsic monocrystalline silicon is used as the cell substrate, and materials such as SiNx and SiOx are used as passivation layers to improve light absorption and protection.
It effectively reduces the requirement for minority carrier diffusion length of solar cells after irradiation, maintains stable output of electrical performance, improves radiation resistance, and reduces electrical performance degradation.
Smart Images
Figure CN121099786A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a solar cell and array, and more particularly to a radiation-resistant solar cell and array. Background Technology
[0002] With the launch of the mega-constellation project and the rise of private aerospace companies, my country's commercial aerospace industry is gradually emerging. Traditional satellite manufacturing costs are extremely high, often exceeding 100 million yuan. Among these costs, multi-junction gallium arsenide solar cells, serving as the energy source, account for more than a quarter of the total satellite cost, making them a core element in reducing costs for commercial aerospace. Based on this, most of SpaceX's Starlink satellites have adopted low-cost crystalline silicon solar cells as their energy source, reducing the cost of solar arrays by more than 90%, thus effectively supporting the low-cost manufacturing of tens of thousands of satellites.
[0003] In the space environment, influenced by solar activity, Earth's radiation, and galactic cosmic rays, there are a large number of charged particles such as protons and electrons. These charged particles, especially high-energy electrons, can cause extremely severe electrical performance degradation of crystalline silicon solar cells, exceeding 25%. Radiation resistance has become the most critical issue restricting the space application of low-cost silicon-based solar cells. The performance degradation of crystalline silicon solar cells caused by charged particle irradiation is mainly due to the sharp reduction in the minority carrier diffusion length of crystalline silicon. Intense charged particle irradiation can cause the minority carrier diffusion length of crystalline silicon solar cells to decrease from several thousand micrometers before irradiation to only a few micrometers after irradiation.
[0004] To reduce the decay caused by charged particle irradiation, previous researchers mainly focused on increasing the resistivity or reducing the thickness of silicon wafers. However, high-resistivity silicon wafers require zone melting, which is extremely costly; while reducing the thickness of the silicon wafer can lead to a sharp increase in the breakage rate during solar cell fabrication and also degrade the mechanical properties of the silicon wafer, affecting its reliability for on-orbit applications. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a radiation-resistant solar cell and array, which can effectively improve the radiation resistance of the solar cell and ensure the output electrical performance of the solar cell after degradation.
[0006] According to the technical solution provided by the present invention, a radiation-resistant solar cell is provided, the solar cell comprising:
[0007] Battery substrate;
[0008] The front cell, located on the front side of the battery substrate, includes at least a front minority carrier selection region covering the front side of the battery substrate and a front minority carrier electrode for leading out the front minority carrier selection region.
[0009] The back-side unit, located on the back side of the battery substrate, includes at least a plurality of back-side minority carrier domain groups and a plurality of back-side majority carrier domain groups, wherein...
[0010] The back minority carrier domain group includes several back minority carrier selection regions and back minority carrier electrodes for leading out the back minority carrier selection regions respectively;
[0011] The back-side majority carrier group includes several back-side majority carrier selection regions and back-side majority carrier electrodes for leading out the back-side majority carrier selection regions respectively;
[0012] The minority carrier selection region and the majority carrier selection region on the back side of the battery substrate are arranged alternately and isolated from each other, and the direction of the alternation is perpendicular to the thickness direction of the battery substrate.
[0013] After the battery substrate is irradiated, a back-side majority carrier selection region captures target majority carriers within the battery substrate and outputs the captured target majority carriers through the corresponding back-side majority carrier electrode. The target majority carriers are majority carriers within the capture range of the back-side majority carrier selection region.
[0014] The target minority carriers in the battery substrate are captured by a back minority carrier selection region and / or a front minority carrier selection region, and the captured target minority carriers are output through the corresponding back minority carrier electrode and front minority carrier electrode. The target minority carriers are the minority carriers within the capture range of the back minority carrier selection region and the front minority carrier selection region.
[0015] For any two adjacent back minority carrier selection regions and back majority carrier selection regions, when capturing target minority carriers in the battery substrate based on the front minority carrier selection region and the back minority carrier selection region, and capturing target majority carriers in the battery substrate based on the back majority carrier selection region, then:
[0016] A / a1 < B / b and A / a2 < B / b
[0017] Where A is the diffusion length of the target minority carrier in the battery substrate, B is the diffusion length of the target majority carrier in the battery substrate, a1 is the migration distance between the target minority carrier and the front minority carrier selection region, a2 is the migration distance between the target minority carrier and the back minority carrier selection region, and b is the distance between the majority carrier and the back majority carrier selection region.
[0018] The front unit cell also includes a front anti-reflection passivation layer, wherein...
[0019] The front minority carrier selection region fully covers the front side of the battery substrate, and the front anti-reflection passivation layer covers the front minority carrier selection region;
[0020] One or more front minority carrier electrodes are electrically connected to the front minority carrier selection region through the front anti-reflection passivation layer to bring out the front minority carrier selection region.
[0021] The front anti-reflection passivation layer includes one or more of SiNx, SiOx, SiNxOy, AlOx, ITO, SnO2, MgF2, TiOx, and ZnO.
[0022] The back-side unit body also includes a back-side protective passivation layer, wherein...
[0023] The back protection passivation layer covers the back minority carrier selection region, the back majority carrier selection region, and the back side of the battery substrate, and isolates the back minority carrier selection region from the adjacent back majority carrier selection region through the back protection passivation layer.
[0024] The back minority carrier electrode passes through the back protective passivation layer and is electrically connected to the corresponding back minority carrier selection region to bring out the back minority carrier selection region;
[0025] The back majority carrier electrode passes through the back protective passivation layer and is electrically connected to the corresponding back majority carrier selection region to bring out the back majority carrier selection region.
[0026] When setting a front minority carrier selection region, a back minority carrier selection region, or a back majority carrier selection region, the setting method includes forming it based on a doping process on the battery substrate, or forming it based on a passivated contact structure prepared on the battery substrate.
[0027] When a passivation contact structure is formed on a battery substrate, the passivation contact structure includes a tunneling layer in contact with the battery substrate and a polarity selection layer disposed on the tunneling layer, wherein...
[0028] The polarity selection layer includes one of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped metal oxide thin film;
[0029] When the polarity selection layer is a doped metal oxide thin film, the polarity selection layer includes one of MoOx thin film, WOx thin film, ZnO thin film or MgOx thin film;
[0030] The tunneling layer comprises one of intrinsic amorphous silicon, silicon oxide, aluminum oxide, and SnOx.
[0031] The battery substrate includes one of high-resistivity monocrystalline silicon, intrinsic monocrystalline silicon, polycrystalline silicon, perovskite, GaAs, CIGS, or CdTe.
[0032] When the battery substrate is high-resistivity monocrystalline silicon or intrinsic monocrystalline silicon, the resistivity of the battery substrate is not less than 10 Ω·cm.
[0033] A radiation-resistant solar cell array, the solar cell array comprising the solar cells described above.
[0034] The advantages of this invention are as follows: By setting a front minority carrier selection region on the front side of the battery substrate and a back minority carrier selection region on the back side of the battery substrate, minority carrier capture capability is achieved on both the front and back sides of the battery substrate. Thus, even after the solar cell decays, minority carriers within the battery substrate can still be effectively captured. Therefore, minority carriers can be output from the nearest back minority carrier selection region or front minority carrier selection region, which can reduce the requirement of the solar cell performance on the minority carrier diffusion length by half, thereby effectively ensuring the electrical output performance of the solar cell under low minority carrier lifetime conditions after decay. Attached Figure Description
[0035] Figure 1 This is a schematic diagram of the structure of one embodiment of the solar cell of the present invention.
[0036] Figure 2 This is a schematic diagram of an embodiment of an existing solar cell.
[0037] Figure 3 for Figure 1 , Figure 2 A comparative schematic diagram of an embodiment of the energy conversion efficiency of a solar cell.
[0038] Explanation of reference numerals in the attached figures: 1-battery substrate, 2-backside minority carrier selection region, 3-backside majority carrier selection region, 4-frontside minority carrier selection region, 5-backside protective passivation layer, 6-frontside anti-reflection passivation layer, 7-backside minority carrier electrode, 8-backside majority carrier electrode, 9-frontside minority carrier electrode, 10-battery substrate, 11-substrate backside majority carrier selection layer, 12-substrate frontside minority carrier selection layer, 13-substrate anti-reflection passivation layer, 14-substrate minority carrier electrode, 15-substrate protective passivation layer, 16-substrate minority carrier electrode. Detailed Implementation
[0039] The present invention will be further described below with reference to specific accompanying drawings and embodiments.
[0040] To effectively improve the radiation resistance of solar cells and ensure their output electrical performance after degradation, this invention provides a radiation-resistant solar cell, specifically, the solar cell comprising:
[0041] Battery substrate 1;
[0042] The front unit body, located on the front side of the battery substrate 1, includes at least a front minority carrier selection region 4 covering the front side of the battery substrate 1 and a front minority carrier electrode 9 for leading out the front minority carrier selection region 4.
[0043] The back-side unit, located on the back side of the battery substrate, includes at least a plurality of back-side minority carrier domain groups and a plurality of back-side majority carrier domain groups, wherein...
[0044] The back minority carrier domain group includes a plurality of back minority carrier selection regions 2 and back minority carrier electrodes 7 for leading out the back minority carrier selection regions respectively;
[0045] The back-side majority carrier group includes a plurality of back-side majority carrier selection regions 3 and back-side majority carrier electrodes 8 for leading out the back-side majority carrier selection regions 3 respectively.
[0046] The minority carrier selection region 2 and the majority carrier selection region 3 on the back side of the battery substrate 1 are arranged alternately and isolated from each other, and the direction of the alternation is perpendicular to the thickness direction of the battery substrate 1.
[0047] After the battery substrate 1 is irradiated, a back-side majority carrier selection region 3 captures the target majority carriers within the battery substrate 1 and outputs the captured target majority carriers through the corresponding back-side majority carrier electrode 8. The target majority carriers are the majority carriers within the capture range of the back-side majority carrier selection region 3.
[0048] The target minority carriers in the battery substrate 1 are captured by a back minority carrier selection region 2 and / or a front minority carrier selection region 4, and the captured target minority carriers are output through the corresponding back minority carrier electrode 7 and front minority carrier electrode 9. The target minority carriers are the minority carriers within the capture range of the back minority carrier selection region 2 and the front minority carrier selection region 4.
[0049] It should be noted that the solar cell of the present invention can be a single-junction solar cell or a tandem solar cell. Similar to existing solar cells, the solar cell of the present invention also includes a cell substrate 1. Specifically, the cell substrate 1 includes one of high-resistivity monocrystalline silicon, intrinsic monocrystalline silicon, polycrystalline silicon, perovskite, GaAs, CIGS, or CdTe. In addition, when the cell substrate 1 is high-resistivity monocrystalline silicon or intrinsic monocrystalline silicon, the resistivity of the cell substrate 1 is not less than 10 Ω·cm, so that the solar cell of the present invention can have better resistance to space charged particle irradiation.
[0050] Generally, the battery substrate 1 has two corresponding surfaces, namely the front surface and the back surface of the battery substrate 1. The use of two corresponding surfaces to form the front and back surfaces of the battery substrate 1 is consistent with the prior art and will not be described in detail here. In order to form a solar cell, a front unit should be provided on the front surface of the battery substrate 1 and a back unit should be provided on the back surface of the battery substrate 1. The specific details of providing the front and back units are described below.
[0051] In specific implementation, the front unit generally includes at least a front minority carrier selection region 4 and a front minority carrier electrode 9. The front minority carrier selection region 4 can capture minority carriers near the front of the battery substrate 1 and output them through the front minority carrier electrode 9. The minority carriers captured by the front minority carrier selection region 4 are the minority carriers in the battery substrate 1. It can be understood that the minority carriers in the battery substrate 1 are related to the conductivity type of the battery substrate 1. For example, when the conductivity type of the battery substrate 1 is P-type, the minority carriers in the battery substrate 1 are electrons, and the majority carriers in the battery substrate 1 are holes; when the conductivity type of the battery substrate 1 is N-type, the minority carriers in the battery substrate 1 are holes, and the majority carriers are electrons.
[0052] To improve radiation resistance and ensure the output electrical performance of solar cells after degradation, in one embodiment of the present invention, the back-side unit may include a back-side minority carrier domain group and a back-side majority carrier domain group. The back-side minority carrier domain group includes one or more back-side minority carrier selection regions 2. Each back-side minority carrier selection region 2 is connected to a corresponding back-side minority carrier selection region 2 via a back-side minority carrier electrode 7. Specifically, the back-side minority carrier electrode 7 corresponds one-to-one with the back-side minority carrier selection region 2. The back-side majority carrier domain group includes one or more back-side majority carrier selection regions 3. Similar to the back-side minority carrier domain group, each back-side majority carrier selection region 3 is provided with a back-side majority carrier electrode 8, which connects the corresponding back-side majority carrier selection region 3.
[0053] As can be seen from the above description, multiple back-side minority carrier selection regions 2 and multiple back-side majority carrier selection regions 3 are generally provided on the back side of the battery substrate 1. The back-side minority carrier selection regions 2 and the back-side majority carrier selection regions 3 are arranged alternately and isolated from each other on the back side of the battery substrate 1. Figure 1 The figure shows a cross-sectional view of an embodiment of a solar cell. As can be seen from the figure, the back minority carrier selection region 2 and the back majority carrier selection region 3 are located on the back side of the cell substrate 1. Figure 1 The battery substrates 1 shown are arranged alternately along their length direction, and the arrangement direction is perpendicular to the thickness direction of the battery substrates 1.
[0054] Generally, the minority carrier selection region 2 and the majority carrier selection region 3 on the back side of the battery substrate 1 are distributed in an elongated strip shape, that is, multiple strip-shaped minority carrier selection regions 2 and majority carrier selection regions 3 can be formed on the back side of the battery substrate 1. It can be understood that the minority carriers in the battery substrate 1 can be captured by the minority carrier selection region 2, and the captured minority carriers are output through the minority carrier electrode 7. The majority carriers in the battery substrate 1 can be captured by the majority carrier selection region 3, and the captured majority carriers are output through the majority carrier electrode 8. The specific capture method can be consistent with the prior art.
[0055] During operation, the battery substrate 1 is irradiated, generating majority and minority carriers. A back-side majority carrier selection region 3 then captures target majority carriers within the battery substrate 1 and outputs them via the corresponding back-side majority carrier electrode 8. As explained above, each back-side majority carrier selection region 3 is distributed at different locations within the battery substrate 1. Generally, the back-side majority carrier selection region 3 can capture majority carriers within its capture range, and the captured majority carriers form the target majority carriers.
[0056] For minority carriers in the battery substrate 1, target minority carriers in the battery substrate 1 are captured by a back minority carrier selection region 2 and / or a front minority carrier selection region 4, and the captured target minority carriers are output through the corresponding back minority carrier electrode 7 and front minority carrier electrode 9. Similar to target majority carriers, target minority carriers should be minority carriers within the capture range of the back minority carrier selection region 2 and the front minority carrier selection region 4.
[0057] As explained in the background technology, after a solar cell decays, the diffusion length of minority carriers decreases sharply. When a front minority carrier selection region 4 is set on the front side of the solar cell substrate 1 and a back minority carrier selection region 2 is set on the back side of the solar cell substrate 1, both the front and back sides of the solar cell substrate 1 have minority carrier capture capabilities. Thus, even after the solar cell decays, minority carriers in the solar cell substrate 1 can still be effectively captured. Therefore, minority carriers can be output from the nearest back minority carrier selection region 2 or front minority carrier selection region 4, which can reduce the requirement of the solar cell performance on the minority carrier diffusion length by half, thereby effectively ensuring the electrical output performance of the solar cell under the condition of low minority carrier lifetime after decay.
[0058] In one embodiment of the present invention, the front unit body further includes a front anti-reflection passivation layer 6, wherein,
[0059] The front minority carrier selection region 4 fully covers the front side of the battery substrate 1, and the front anti-reflection passivation layer 6 covers the front minority carrier selection region 4;
[0060] One or more front minority carrier electrodes 9 pass through the front anti-reflection passivation layer 6 and are electrically connected to the front minority carrier selection region 4 to bring out the front minority carrier selection region 4.
[0061] Depend on Figure 1 It can be seen that the front cell may also include a front anti-reflection passivation layer 6. The front anti-reflection passivation layer 6 can be used to achieve anti-reflection and passivation protection. Anti-reflection can improve the light absorption efficiency and photoelectric conversion efficiency of the battery substrate 1, and passivation protection can protect the front minority carrier selection region 4. As shown in the figure, the front anti-reflection passivation layer 6 should be disposed on the front minority carrier selection region 4, and multiple front minority carrier electrodes 9 pass through the front anti-reflection passivation layer 6 and are electrically connected to the front minority carrier selection region 4.
[0062] In specific implementation, the front anti-reflection passivation layer 6 includes one or more of SiNx, SiOx, SiNxOy, AlOx, ITO, SnO2, MgF2, TiOx, and ZnO; of course, the front anti-reflection passivation layer 6 can also be other material types, which can be selected according to needs, and the specific selection should meet the requirements of anti-reflection and passivation protection. It is understood that the type of front anti-reflection passivation layer 6 used here can be consistent with the existing technology, and will not be elaborated here. Other similar types can be referred to here.
[0063] In one embodiment of the present invention, the back-side unit body further includes a back-side protective passivation layer 5, wherein,
[0064] The back protection passivation layer 5 covers the back minority carrier selection region 2, the back majority carrier selection region 3 and the back side of the battery substrate 1, and isolates the back minority carrier selection region 2 from the adjacent back majority carrier selection region 3 through the back protection passivation layer 5.
[0065] The back minority carrier electrode 7 passes through the back protective passivation layer 5 and is electrically connected to the corresponding back minority carrier selection region 2 to bring out the back minority carrier selection region 2;
[0066] The back majority carrier electrode 8 passes through the back protective passivation layer 5 and is electrically connected to the corresponding back majority carrier selection region 3 to bring out the back majority carrier selection region 3.
[0067] In order to protect and isolate the minority carrier selection region 2 and the majority carrier selection region 3 on the back side, the back side unit body should also include a back side protective passivation layer 5. Figure 1 The diagram shows an embodiment in which the back passivation protection layer 5 is disposed on the back side of the battery substrate 1. The back passivation protection layer 5 can take the same form as the front anti-reflection passivation layer 6. For details, please refer to the description of the front anti-reflection passivation layer 6 above, which will not be repeated here.
[0068] In one embodiment of the present invention, when a front minority carrier selection region 4, a back minority carrier selection region 2, or a back majority carrier selection region 3 are provided, the method of providing the region includes forming it based on a doping process on a battery substrate 1, or forming it based on a passivated contact structure prepared on the battery substrate 1.
[0069] As can be seen from the above description, the front minority carrier selection region 4 and the back minority carrier selection region 2 are mainly used for capturing minority carriers, while the back majority carrier selection region 3 is mainly used for capturing majority carriers. Therefore, the front minority carrier selection region 4, the back minority carrier selection region 2, or the back majority carrier selection region 3 can be prepared or disposed on the battery substrate 1 in the same way. Of course, they can also be prepared / disposed on the battery substrate 1 in different ways. The preparation / disposition methods are described in detail below.
[0070] Specifically, a doping process can be performed on the battery substrate 1 to form a minority carrier selection region or a majority carrier selection region. If the conductivity type of the battery substrate 1 is P-type, boron ion implantation or boron thermal diffusion can be performed on the back side of the battery substrate 1 to form a back majority carrier selection region 3 in the battery substrate 1. Similarly, the back minority carrier selection region 2 and the front minority carrier selection region 4 can be formed by ion implantation or thermal diffusion. The specific process conditions, process methods and processes for forming the front minority carrier selection region 4, the back minority carrier selection region 2 or the back majority carrier selection region 3 through the doping process can be consistent with the prior art and will not be elaborated here.
[0071] In one embodiment of the present invention, when a passivation contact structure is formed on a battery substrate 1, the passivation contact structure includes a tunneling layer in contact with the battery substrate 1 and a polarity selection layer disposed on the tunneling layer, wherein,
[0072] The polarity selection layer includes one of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped metal oxide thin film;
[0073] When the polarity selection layer is a doped metal oxide thin film, the polarity selection layer includes one of MoOx thin film, WOx thin film, ZnO thin film or MgOx thin film;
[0074] The tunneling layer comprises one of intrinsic amorphous silicon, silicon oxide, aluminum oxide, and SnOx.
[0075] It should be understood that when the aforementioned front minority carrier selection region 4, back minority carrier selection region 2, or back majority carrier selection region 3 are prepared using a doping process, the front minority carrier selection region 4, back minority carrier selection region 2, or back majority carrier selection region 3 should be located within the battery substrate 1. When a passivation contact structure prepared on the battery substrate 1 is formed, the front minority carrier selection region 4 should be located on the front side of the battery substrate 1, while the back minority carrier selection region 2 or back majority carrier selection region 3 should be located on the back side of the battery substrate 1.
[0076] In specific implementation, the passivation contact structure includes at least a tunneling layer in contact with the battery substrate 1 and a polarity selection layer disposed on the tunneling layer. The polarity selection layer includes one of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and undoped metal oxide thin films. Of course, the conductivity type of the polarity selection layer should meet the conductivity type requirements of the majority carrier selection region or the minority carrier selection region. For example, if the conductivity type of the battery substrate 1 is P-type, the conductivity type of the polarity selection layer in the back majority carrier selection region 3 should also be P-type, while the conductivity type of the corresponding polarity selection layers in the front minority carrier selection region 4 and the back minority carrier selection region 2 should be N-type. Other cases can be referred to the explanation here, and will not be repeated here. Furthermore, the tunneling layer includes one of intrinsic amorphous silicon, silicon oxide, aluminum oxide, and SnOx.
[0077] In practice, the back minority carrier electrode 7, the back majority carrier electrode 8, and the front minority carrier electrode 9 can be achieved by screen printing and sintering, or by other methods such as electroplating and vapor deposition. The electrode materials used can be highly conductive materials such as Ag, Cu, Al, and Ni, or their stacked film structures. The method of preparing the back minority carrier electrode 7, the back majority carrier electrode 8, and the front minority carrier electrode 9 can be consistent with the existing technology, and can be selected according to the needs, which will not be elaborated here.
[0078] In one embodiment of the present invention, for any two adjacent back minority carrier selection regions 2 and back majority carrier selection regions 3, when the target minority carriers in the battery substrate 1 are captured based on the front minority carrier selection region 4 and the back minority carrier selection region 2, and the target majority carriers in the battery substrate 1 are captured based on the back majority carrier selection region 3, then:
[0079] A / a1 < B / b and A / a2 < B / b
[0080] Where A is the diffusion length of the target minority carrier in the battery substrate 1, B is the diffusion length of the target majority carrier in the battery substrate 1, a1 is the migration distance between the target minority carrier and the front minority carrier selection region 4, a2 is the migration distance between the target minority carrier and the back minority carrier selection region 2, and b is the distance between the majority carrier and the neighboring back majority carrier selection region 3.
[0081] For solar cells, depending on their carrier trapping interface, the majority carrier diffusion length is typically several to tens of times greater than the minority carrier diffusion length. Towards the end of a solar cell's lifespan, both the minority and majority carrier diffusion lengths decrease sharply, resulting in minority-majority carrier pairs within the cell substrate 1. The minority carrier diffusion length is A, which, under severe degradation, becomes less than the thickness of the cell substrate 1, while the majority carrier diffusion length is B. In practical implementation, the minority carrier diffusion length A and the majority carrier diffusion length B at the end of the solar cell's lifespan can be measured using techniques commonly used in this field.
[0082] Figure 1The figure illustrates an embodiment of generating minority carrier-majority carrier pairs within a battery substrate 1. In the figure, the migration distance of the generated minority carriers from the back minority carrier selection region 2 is a2, and the migration distance from the front minority carrier selection region 4 is a1. The distance of the generated majority carriers from the back majority carrier selection region 3 is b. To achieve radiation resistance, the width of the back minority carrier selection region 2, the width of the back majority carrier selection region 3, and the spacing between the back minority carrier selection region 2 and the back majority carrier selection region 3 need to be reduced specifically according to the carrier capture interface. This ensures that minority carrier recombination is a weak link in carrier recombination. At this time, it should be ensured that A / a1 < B / b and A / a2 < B / b. Therefore, the width of the back minority carrier selection region 2, the width of the back majority carrier selection region 3, and the spacing between the back minority carrier selection region 2 and the back majority carrier selection region 3 can be selected and set according to these conditions.
[0083] To verify the radiation resistance of the solar cell of this invention, the following will be performed. Figure 2 The diagram shows a comparison between existing solar cells and the solar cell of this invention. The following section compares them. Figure 2 The parameters of the solar cell in the present invention, as well as those of the solar cell in the comparative example, are illustrated by examples. Specifically:
[0084] Figure 2 The solar cell includes a substrate 10. A back-side majority carrier select layer 11 is disposed on the back side of the substrate 10, and a substrate protective passivation layer 15 is disposed on the back-side majority carrier select layer 11. Furthermore, the back-side majority carrier select layer 11 is electrically connected to a substrate majority carrier electrode 16. A front-side minority carrier select layer 12 is disposed on the front side of the substrate 10, and a substrate anti-reflection passivation layer 13 is disposed on the front-side minority carrier select layer 12. The front-side minority carrier select layer 12 is electrically connected to a substrate minority carrier electrode 14. In specific implementations, the substrate 10 can correspond to the battery substrate 1 of the present invention. For details, please refer to the description of the battery substrate 1 above. Furthermore, the back-side majority carrier select layer 11 and the front-side minority carrier select layer 12 can also be described in the corresponding description above, and will not be repeated here.
[0085] In comparison, the battery substrate 10 is a P-type monocrystalline silicon wafer with a resistivity of 10 Ω·cm and a thickness of 120 μm. In this case, the minority carriers of the solar cell are electrons and the majority carriers are holes. Both the majority carrier selection layer 11 on the back side of the substrate and the minority carrier selection layer 12 on the front side of the substrate adopt a passivated contact structure. The majority carrier selection layer 11 on the back side of the substrate uses ultrathin SiOx (silicon oxide) as a tunneling layer and boron-doped polycrystalline silicon as a polarity selection layer to achieve hole selectivity. The minority carrier selection layer 12 on the front side of the substrate uses ultrathin SiOx as a tunneling layer and phosphorus-doped polycrystalline silicon as a polarity selection layer to achieve electron selectivity. The substrate protective passivation layer 15 and the substrate anti-reflection passivation layer 13 are SiNx layers. The substrate minority carrier electrode 14 and the substrate majority carrier electrode 16 are obtained by screen printing and sintering with photovoltaic silver paste.
[0086] The battery substrate 1 of this invention is a p-type monocrystalline silicon wafer with a resistivity of 10 Ω·cm and a thickness of 120 μm. In this case, the minority carriers in the solar cell are electrons. The front minority carrier selection region 4 and the back minority carrier selection region 2 or the back majority carrier selection region 3 employ a passivated contact structure, as detailed in the description of existing solar cells above. The front anti-reflection passivation layer 6 and the back protective passivation layer 5 are Al2O3 / SiNx layers. The back minority carrier electrode 7, the back majority carrier electrode 8, and the front minority carrier electrode 9 are obtained by screen printing and sintering using photovoltaic silver paste.
[0087] Will Figure 2 The solar cell in the example is used as a comparative example, and the battery of the present invention using the above parameters is used as an application example. During the comparison, the comparative example and the application example are subjected to 1MeV electron irradiation treatment, and then subjected to 1E13, 5E13, 1E14, and 2E14e / cm. 2 The change in solar energy conversion efficiency after a dose of electron irradiation is as follows: Figure 3 As shown.
[0088] Depend on Figure 3 As can be seen, the application examples significantly reduce carrier migration paths, resulting in extremely low electron irradiation attenuation. After 2E14e / cm 2 The energy conversion efficiency of the comparative example after dose electron irradiation was 13.44%, a decrease of 36% compared to the initial level; after 2E14e / cm 2 After dose electron irradiation, the energy conversion efficiency of the application example was 15.33%, which was 29% lower than the initial level. That is, the energy conversion efficiency of the application example after decay was significantly higher than that of the control example, and the decay rate relative to the initial level was also significantly lower than that of the control example, demonstrating excellent resistance to electron irradiation.
[0089] Furthermore, a radiation-resistant solar cell array can also be obtained, the solar cell array comprising the solar cells described above.
[0090] Specifically, the solar cell array should include solar cells distributed in an array. The distribution of the solar cell array can be selected as needed, and will not be elaborated here.
Claims
1. A radiation-resistant solar cell, characterized in that, The solar cell includes: Battery substrate; The front cell, located on the front side of the battery substrate, includes at least a front minority carrier selection region covering the front side of the battery substrate and a front minority carrier electrode for leading out the front minority carrier selection region. The back-side unit, located on the back side of the battery substrate, includes at least a plurality of back-side minority carrier domain groups and a plurality of back-side majority carrier domain groups, wherein... The back minority carrier domain group includes several back minority carrier selection regions and back minority carrier electrodes for leading out the back minority carrier selection regions respectively; The back-side majority carrier group includes several back-side majority carrier selection regions and back-side majority carrier electrodes for leading out the back-side majority carrier selection regions respectively; The minority carrier selection region and the majority carrier selection region on the back side of the battery substrate are arranged alternately and isolated from each other, and the direction of the alternation is perpendicular to the thickness direction of the battery substrate. After the battery substrate is irradiated, a back-side majority carrier selection region captures target majority carriers within the battery substrate and outputs the captured target majority carriers through the corresponding back-side majority carrier electrode. The target majority carriers are majority carriers within the capture range of the back-side majority carrier selection region. The target minority carriers in the battery substrate are captured by a back minority carrier selection region and / or a front minority carrier selection region, and the captured target minority carriers are output through the corresponding back minority carrier electrode and front minority carrier electrode. The target minority carriers are the minority carriers within the capture range of the back minority carrier selection region and the front minority carrier selection region.
2. The radiation-resistant solar cell according to claim 1, characterized in that, For any two adjacent back minority carrier selection regions and back majority carrier selection regions, when capturing target minority carriers in the battery substrate based on the front minority carrier selection region and the back minority carrier selection region, and capturing target majority carriers in the battery substrate based on the back majority carrier selection region, then: A / a1 < B / b and A / a2 < B / b Where A is the diffusion length of the target minority carrier in the battery substrate, B is the diffusion length of the target majority carrier in the battery substrate, a1 is the migration distance between the target minority carrier and the front minority carrier selection region, a2 is the migration distance between the target minority carrier and the back minority carrier selection region, and b is the distance between the majority carrier and the back majority carrier selection region.
3. The radiation-resistant solar cell according to claim 1, characterized in that, The front unit cell also includes a front anti-reflection passivation layer, wherein... The front minority carrier selection region fully covers the front side of the battery substrate, and the front anti-reflection passivation layer covers the front minority carrier selection region; One or more front minority carrier electrodes are electrically connected to the front minority carrier selection region through the front anti-reflection passivation layer to bring out the front minority carrier selection region.
4. The radiation-resistant solar cell according to claim 3, characterized in that, The front anti-reflection passivation layer includes one or more of SiNx, SiOx, SiNxOy, AlOx, ITO, SnO2, MgF2, TiOx, and ZnO.
5. The radiation-resistant solar cell according to claim 1, characterized in that, The back-side unit body also includes a back-side protective passivation layer, wherein... The back protection passivation layer covers the back minority carrier selection region, the back majority carrier selection region, and the back side of the battery substrate, and isolates the back minority carrier selection region from the adjacent back majority carrier selection region through the back protection passivation layer. The back minority carrier electrode passes through the back protective passivation layer and is electrically connected to the corresponding back minority carrier selection region to bring out the back minority carrier selection region; The back majority carrier electrode passes through the back protective passivation layer and is electrically connected to the corresponding back majority carrier selection region to bring out the back majority carrier selection region.
6. The radiation-resistant solar cell according to any one of claims 1 to 5, characterized in that, When setting a front minority carrier selection region, a back minority carrier selection region, or a back majority carrier selection region, the setting method includes forming it based on a doping process on the battery substrate, or forming it based on a passivated contact structure prepared on the battery substrate.
7. The radiation-resistant solar cell according to claim 6, characterized in that, When a passivation contact structure is formed on a battery substrate, the passivation contact structure includes a tunneling layer in contact with the battery substrate and a polarity selection layer disposed on the tunneling layer, wherein... The polarity selection layer includes one of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped metal oxide thin film; When the polarity selection layer is a doped metal oxide thin film, the polarity selection layer includes one of MoOx thin film, WOx thin film, ZnO thin film or MgOx thin film; The tunneling layer comprises one of intrinsic amorphous silicon, silicon oxide, aluminum oxide, and SnOx.
8. The radiation-resistant solar cell according to any one of claims 1 to 5, characterized in that, The battery substrate includes one of high-resistivity monocrystalline silicon, intrinsic monocrystalline silicon, polycrystalline silicon, perovskite, GaAs, CIGS, or CdTe.
9. The radiation-resistant solar cell according to claim 8, characterized in that, When the battery substrate is high-resistivity monocrystalline silicon or intrinsic monocrystalline silicon, the resistivity of the battery substrate is not less than 10 Ω·cm.
10. A radiation-resistant solar cell array, characterized in that, The solar cell array comprises the solar cell according to any one of claims 1 to 9.