Back contact cells, stacked cells and photovoltaic modules

Abstract

The present disclosure relates to the field of photovoltaics, and provides a back contact cell, a laminated cell and a photovoltaic module, which can at least improve the hot spot effect and improve the performance of the back contact cell. The back contact cell comprises a substrate, a first doped semiconductor layer, a second doped semiconductor layer, a first electrode and a second electrode. The substrate comprises opposite first and second surfaces, the first surface comprising first and second regions alternatingly distributed along a first direction; the first doped semiconductor layer is located on the first regions; the second doped semiconductor layer comprises a first crystallized portion and a second crystallized portion, the first crystallized portion being located on the first regions and on a side of the first doped semiconductor layer away from the substrate, and the second crystallized portion being located on the second regions and adjacent to the first crystallized portion; wherein the crystallization rate of the first crystallized portion is less than the crystallization rate of the second crystallized portion, and / or the grain size of the first crystallized portion is less than the grain size of the second crystallized portion.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and in particular to a back-contact battery, a tandem battery, and a photovoltaic module. Background Technology

[0002] As fossil fuels are gradually depleted, solar energy is becoming increasingly widely used as a new energy alternative. A solar cell is a device that converts sunlight into electrical energy. Solar cells utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient use of electrical energy.

[0003] Among them, back-contact solar cells are a type of solar cell where all the grid lines are located on the back of the cell. Back-contact solar cells have no metal grid electrodes obstructing the front, increasing light absorption efficiency and significantly improving short-circuit current. This effectively increases the conversion efficiency of back-contact solar cells, making them a promising technology for future development. Summary of the Invention

[0004] This disclosure provides a back-contact battery, a tandem battery, and a photovoltaic module, which can at least improve the hot spot effect and enhance the performance of the back-contact battery.

[0005] According to some embodiments of this disclosure, one aspect of this disclosure provides a back contact battery, the back contact battery comprising: a substrate, the substrate including a first surface and a second surface opposite to each other, the first surface including a first region and a second region alternately distributed along a first direction; a first doped semiconductor layer, the first doped semiconductor layer being located on the first region; a second doped semiconductor layer, the doping elements in the second doped semiconductor layer having a different conductivity type than the doping elements in the first doped semiconductor layer, the second doped semiconductor layer including a first crystallized portion and a second crystallized portion, the first crystallized portion being located on the first region and on the side of the first doped semiconductor layer opposite to the substrate, the second crystallized portion being located on the second region and adjacent to the first crystallized portion; wherein, the crystallinity of the first crystallized portion is less than the crystallinity of the second crystallized portion, and / or, the grain size of the first crystallized portion is smaller than the grain size of the second crystallized portion; a first electrode, the first electrode being located on the first region and electrically connected to the first doped semiconductor layer; and a second electrode, the second electrode being located on the second region and electrically connected to the second crystallized portion.

[0006] In some embodiments, the second crystallization portion includes: a first sub-crystallization portion located on the second region and also located on the sidewall of the first doped semiconductor layer facing the second region, and adjacent to the first crystallization portion; a second sub-crystallization portion located on the second region and adjacent to the first sub-crystallization portion, and the second sub-crystallization portion also electrically connected to the second electrode; wherein the crystallization rate of the first sub-crystallization portion is less than or equal to the crystallization rate of the second sub-crystallization portion, and / or the grain size of the first sub-crystallization portion is less than or equal to the grain size of the second sub-crystallization portion.

[0007] In some embodiments, the second doped semiconductor layer includes a plurality of first sub-crystallized portions spaced apart along a second direction.

[0008] In some embodiments, the second sub-crystallization portion extends along the second direction and is adjacent to a plurality of the first sub-crystallization portions, and the second sub-crystallization portion is also electrically connected to the second electrode.

[0009] In some embodiments, the second doped semiconductor layer includes a plurality of the first crystallized portions spaced apart along a second direction.

[0010] In some embodiments, the second doped semiconductor layer satisfies: 0.3≤W1 / D1≤0.9, where W1 is the width of the first crystallized portion along the second direction, and D1 is the distance between adjacent first crystallized portions along the second direction.

[0011] In some embodiments, along the second direction, the width of the first crystallized portion is 50 μm to 5000 μm, and the spacing between adjacent first crystallized portions is 20 μm to 5000 μm.

[0012] In some embodiments, the first crystallization portion has a first crystallization rate, and the second crystallization portion has a second crystallization rate, wherein 20% ≤ first crystallization rate < 70%, and 40% ≤ second crystallization rate ≤ 70%.

[0013] In some embodiments, the first crystallization portion has a first grain size, and the second crystallization portion has a second grain size, wherein 5nm ≤ first grain size < 200nm, and 5nm < second grain size ≤ 200nm.

[0014] In some embodiments, the second doped semiconductor layer further includes an amorphous portion located on the side of the first doped semiconductor layer away from the substrate and adjacent to the first crystallized portion.

[0015] In some embodiments, the back contact battery satisfies: L2 / L1≥0.15, where L1 is the sum of the length of the amorphous portion along the first direction and the length of the first crystallized portion along the first direction, and L2 is the length of the first crystallized portion along the first direction.

[0016] In some embodiments, 30μm≤L1≤150μm, 4.5μm≤L2≤150μm.

[0017] In some embodiments, the thickness of the second doped semiconductor layer is 15 nm to 40 nm.

[0018] In some embodiments, the back contact battery further includes a conductive layer located on the surface of the second crystallized portion away from the substrate and electrically connected to the second electrode.

[0019] According to some embodiments of this disclosure, another aspect of this disclosure also provides a stacked battery, the stacked battery including a bottom battery, the bottom battery being a back contact battery as described in any of the above embodiments; and a perovskite battery, the perovskite battery being located on one side of the bottom battery.

[0020] According to some embodiments of this disclosure, another aspect of this disclosure also provides a photovoltaic module, the photovoltaic module comprising: a battery string, which is formed by connecting a plurality of back-contact batteries as described in any of the above embodiments, or by connecting a plurality of stacked batteries as described in the above embodiments; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film away from the battery string.

[0021] The technical solutions provided in this disclosure have at least the following advantages:

[0022] In the technical solution of the back contact battery provided in this disclosure, the second doped semiconductor layer includes a first crystallized portion and a second crystallized portion. The first crystallized portion and the second crystallized portion are the crystallized parts of the second doped semiconductor layer. Compared with the uncrystallized portion, the first crystallized portion and the second crystallized portion have lower sheet resistance and stronger conductivity, which allows the back contact battery to form a leakage path when it is shaded or experiences localized abnormal heating. This prevents the current from being concentrated entirely in the shaded or abnormally heated area of ​​the back contact battery, thereby reducing the current density in the shaded or abnormally heated area and helping to reduce the heating power in the shaded or abnormally heated area, thus improving the hot spot effect of the back contact battery.

[0023] If the crystallinity of the first crystallized portion is less than that of the second crystallized portion, on the one hand, the larger crystallinity of the second crystallized portion results in a lower sheet resistance and stronger conductivity. Since the second crystallized portion is electrically connected to the second electrode, it can improve the efficiency of the second electrode in collecting charge carriers, thereby improving the performance of the back contact battery. On the other hand, the smaller crystallinity of the first crystallized portion results in a higher sheet resistance and weaker conductivity, which hinders current flow between the entire first and second doped semiconductor layers. This avoids excessive current in the leakage path between the first and second doped semiconductor layers, ensuring a high photoelectric conversion efficiency for the back contact battery. In other words, both of these aspects contribute to improving the performance of the back contact battery.

[0024] If the grain size of the first crystallized portion is smaller than that of the second crystallized portion, on the one hand, the smaller grain size of the second crystallized portion results in a lower sheet resistance and stronger conductivity. Since the second crystallized portion is electrically connected to the second electrode, the efficiency of the second electrode in collecting charge carriers can be improved, thereby enhancing the performance of the back contact battery. On the other hand, the smaller grain size of the first crystallized portion results in a higher sheet resistance and weaker conductivity, which hinders current flow between the entire first and second doped semiconductor layers. This prevents excessive current in the leakage path between the first and second doped semiconductor layers, ensuring a high photoelectric conversion efficiency for the back contact battery. In other words, both of these aspects contribute to improving the performance of the back contact battery.

[0025] Therefore, in the back contact battery provided in this disclosure, the crystallization rate of the first crystallization portion is less than that of the second crystallization portion, and / or the grain size of the first crystallization portion is less than that of the second crystallization portion, which can improve the performance of the back contact battery. Attached Figure Description

[0026] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of a back contact battery provided in an embodiment of this disclosure;

[0028] Figure 2This is a schematic diagram of another structure of the back contact battery provided in an embodiment of this disclosure;

[0029] Figure 3 A partial top view of the second doped semiconductor layer in a back contact battery provided in an embodiment of this disclosure;

[0030] Figure 4 This is a schematic diagram of a stacked battery provided in an embodiment of the present disclosure;

[0031] Figure 5 This is a partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in an embodiment of this disclosure;

[0032] Figure 6 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in an embodiment of this disclosure.

[0033] Explanation of reference numerals in the attached figures:

[0034] 100, Substrate; 110, First surface; 120, Second surface; 130, First region; 140, Second region; 101, First doped semiconductor layer; 102, Second doped semiconductor layer; 112, First crystallized portion; 122, Second crystallized portion; 1221, First sub-crystallized portion; 1222, Second sub-crystallized portion; 132, Amorphous portion; 103, First electrode; 104, Second electrode; 105, Conductive layer; 106, Conductive film; 107, First passivation layer; 108, Second passivation layer; 109, Third passivation layer; 200, Base cell; 201, Perovskite cell; 300, Back contact cell; 301, Encapsulating film; 302, Cover plate; 303, Solder ribbon. Detailed Implementation

[0035] Currently, when back-contact batteries are partially obstructed or malfunction, hot spots can occur on the back-contact batteries. Hot spots refer to the phenomenon where certain areas of the back-contact battery or module experience significantly higher temperatures than other parts due to localized overheating. This phenomenon is usually caused by uneven current distribution or excessively high local resistance, and can severely impact battery performance and lifespan. Therefore, it is necessary to improve the hot spot phenomenon in back-contact batteries.

[0036] In the back contact battery provided in this embodiment, the second doped semiconductor layer includes a first crystallized portion and a second crystallized portion. The first crystallized portion and the second crystallized portion are the crystallized parts of the second doped semiconductor layer. Compared with the uncrystallized portion, the first crystallized portion and the second crystallized portion have lower sheet resistance and stronger conductivity, which allows the back contact battery to form a leakage path when it is shaded or experiences localized abnormal heating. This prevents the current from being concentrated entirely in the shaded or abnormally heated area of ​​the back contact battery, thereby improving the hot spot effect of the back contact battery.

[0037] If the crystallinity of the first crystallized portion is less than that of the second crystallized portion, on the one hand, the larger crystallinity of the second crystallized portion results in a lower sheet resistance and stronger conductivity. Since the second crystallized portion is electrically connected to the second electrode, it can improve the efficiency of the second electrode in collecting charge carriers, thereby improving the performance of the back contact battery. On the other hand, the smaller crystallinity of the first crystallized portion results in a higher sheet resistance and weaker conductivity, which hinders current flow between the entire first and second doped semiconductor layers. This avoids excessive current in the leakage path between the first and second doped semiconductor layers, ensuring a high photoelectric conversion efficiency for the back contact battery. In other words, both of these aspects contribute to improving the performance of the back contact battery.

[0038] If the grain size of the first crystallized portion is smaller than that of the second crystallized portion, on the one hand, the smaller grain size of the second crystallized portion results in a lower sheet resistance and stronger conductivity. Since the second crystallized portion is electrically connected to the second electrode, the efficiency of the second electrode in collecting charge carriers can be improved, thereby enhancing the performance of the back contact battery. On the other hand, the smaller grain size of the first crystallized portion results in a higher sheet resistance and weaker conductivity, which hinders current flow between the entire first and second doped semiconductor layers. This prevents excessive current in the leakage path between the first and second doped semiconductor layers, ensuring a high photoelectric conversion efficiency for the back contact battery. In other words, both of these aspects contribute to improving the performance of the back contact battery.

[0039] Therefore, in the back contact battery provided in this disclosure, the crystallization rate of the first crystallization portion is less than that of the second crystallization portion, and / or the grain size of the first crystallization portion is less than that of the second crystallization portion, which can improve the performance of the back contact battery.

[0040] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0041] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0042] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0043] In the description of embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0044] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0045] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0046] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0047] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Additionally, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0048] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0049] Figure 1 A schematic diagram of a back contact battery provided in an embodiment of this disclosure; Figure 2 This is another schematic diagram of the back contact battery provided in an embodiment of this disclosure. Figure 1 and Figure 2 The difference is that, Figure 1 The second doped semiconductor layer does not contain an amorphous portion, while Figure 2 The second doped semiconductor layer contains an amorphous portion.

[0050] refer to Figure 1 and Figure 2The back contact battery includes: a substrate 100, a first doped semiconductor layer 101, a second doped semiconductor layer 102, a first electrode 103, and a second electrode 104. The substrate 100 includes opposing first surfaces 110 and 120. The first surface 110 includes alternating first regions 130 and 140 along a first direction X. The first doped semiconductor layer 101 is located on the first region 130. The doping elements in the second doped semiconductor layer 102 have different conductivity types than the doping elements in the first doped semiconductor layer 101. The second doped semiconductor layer 102 includes a first crystallized portion 112 and a second crystallized portion 122. The first crystallized portion 112 is located on the first region 130 and is located on the first doped semiconductor layer 104. The doped semiconductor layer 101 is located on the side opposite to the substrate 100. The second crystallized portion 122 is located on the second region 140 and is adjacent to the first crystallized portion 112. The crystallization rate of the first crystallized portion 112 is less than that of the second crystallized portion 122, and / or the grain size of the first crystallized portion 112 is less than that of the second crystallized portion 122. The first electrode 103 is located on the first region 130 and is electrically connected to the first doped semiconductor layer 101. The second electrode 104 is located on the second region 140 and is electrically connected to the second crystallized portion 122.

[0051] The substrate 100 is used to receive incident light and generate photogenerated carriers. In some embodiments, the substrate 100 may be a semiconductor substrate.

[0052] In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon.

[0053] In some embodiments, the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, copper indium selenide, etc.

[0054] The substrate 100 can also be a sapphire substrate, a silicon substrate on an insulator, or a germanium substrate on an insulator.

[0055] The substrate 100 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant element, which can be at least one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type dopant element, which can be at least one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0056] The substrate 100 has a first surface 110 and a second surface 120 facing each other. In some embodiments, the back contact battery is a single-sided battery, in which case the first surface 110 can serve as a light-receiving surface for receiving incident light, and the second surface 120 serves as a back-lighting surface. In some embodiments, the back contact battery is a double-sided battery, in which case both the first surface 110 and the second surface 120 can serve as light-receiving surfaces and can both be used to receive incident light. It is understood that the back-lighting surface referred to in the embodiments of this disclosure can also receive incident light, but the degree of reception of incident light is weaker than that of the light-receiving surface, and therefore it is defined as a back-lighting surface.

[0057] In some embodiments, a flocking process may be performed on at least one of the first surface 110 and the second surface 120 to form a flocked surface on at least one of the first surface 110 and the second surface 120, thereby enhancing the absorption and utilization rate of incident light by the first surface 110 and the second surface 120.

[0058] It should be noted that the first region 130 and the second region 140 are artificially defined regions. The first region 130 is the region where the first doped semiconductor layer 101 is projected onto the substrate 100, and the second region 140 is the region where the second crystallized portion 122 is projected onto the substrate 100.

[0059] The doping element in the first doped semiconductor layer 101 is either a P-type doping element or an N-type doping element, and the doping element in the second doped semiconductor layer 102 is either a P-type doping element or an N-type doping element.

[0060] In some embodiments, the first doped semiconductor layer 101 may be doped polysilicon, which has good electrical conductivity and can effectively transport charge carriers.

[0061] The second doped semiconductor layer 102 includes a first crystallized portion 112 and a second crystallized portion 122. The first crystallized portion 112 and the second crystallized portion 122 are the crystallized portions of the second doped semiconductor layer 102. The crystallization rate of both the first crystallized portion 112 and the second crystallized portion 122 is greater than 0.

[0062] The first crystallization portion 112 is located on the first region 130 and on the side of the first doped semiconductor layer 101 facing away from the substrate 100. When the back contact battery is shielded or experiences localized abnormal heating, the first crystallization portion 112 can form a leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, so that the current is not all concentrated in the shielded area or abnormally heated area of ​​the back contact battery, thereby reducing the current density in the shielded area or abnormally heated area, which helps to reduce the heating power in the shielded area or abnormally heated area, thereby improving the hot spot effect of the back contact battery.

[0063] The first crystallization portion 112 and the second crystallization portion 122 are the crystallized portions in the second doped semiconductor layer 102.

[0064] The crystallization process of the first crystallized portion 112 and the second crystallized portion 122 may include: providing an initial doped semiconductor layer, the initial doped semiconductor layer including an initial first crystallized portion and an initial second crystallized portion; irradiating the initial first crystallized portion and the initial second crystallized portion with a laser of wavelength of 355nm or 532nm, so that the initial first crystallized portion is transformed into the first crystallized portion 112 and the initial second crystallized portion is transformed into the second crystallized portion 122. During laser irradiation, the initial first crystallized portion and the initial second crystallized portion receive different laser irradiation energies per unit time, resulting in the crystallization rate of the first crystallized portion 112 being less than that of the second crystallized portion 122, and / or, the grain size of the first crystallized portion 112 being smaller than that of the second crystallized portion 122.

[0065] The material of the initial doped semiconductor layer can be amorphous silicon.

[0066] It should be noted that grain size refers to the diameter of the grains.

[0067] In some embodiments, the first crystallization portion 112 has a first crystallization rate, and the second crystallization portion 122 has a second crystallization rate, wherein 20% ≤ first crystallization rate < 70%, and 40% ≤ second crystallization rate ≤ 70%.

[0068] The first crystallinity can be 20%, 30%, 40%, 50%, 60%, 65%, or 69%. The first crystallinity is negatively correlated with the sheet resistance of the first crystallized portion 112. When the first crystallinity is within the above range, the first crystallinity is moderate. This avoids the first crystallinity being too small, resulting in an excessively large sheet resistance of the first crystallized portion 112, which would lead to an insufficient current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, making it difficult to effectively improve the hot spot effect. It also avoids the first crystallinity being too large, resulting in an excessively small sheet resistance of the first crystallized portion 112, which would lead to an excessively large current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, affecting the performance of the back contact battery.

[0069] The second crystallinity can be 40%, 50%, 55%, 60%, 65%, or 70%. Within the above range, a larger second crystallinity results in a smaller sheet resistance of the second crystallized portion 122, which can improve the efficiency of the second electrode 104 in collecting charge carriers, thereby improving the performance of the back contact battery.

[0070] It should be noted that the first crystallization rate of the first crystallization section 112 refers to the average crystallization rate of each region within the first crystallization section 112. In other words, the first crystallization rate reflects the average degree of crystallization of the first crystallization section 112. In some cases, the crystallization rate of each region within the first crystallization section 112 is within the range of the first crystallization rate; in other cases, the crystallization rate of most regions within the first crystallization section 112 is within the range of the first crystallization rate, while a small portion is outside this range, but the overall average crystallization rate of the first crystallization section 112 is still the first crystallization rate.

[0071] Similarly, the second crystallization rate of the second crystallization section 122 refers to the average crystallization rate of each region in the second crystallization section 122. In other words, the second crystallization rate reflects the average degree of crystallization of the second crystallization section 122. In some cases, the crystallization rate of each region in the second crystallization section 122 is within the range of the second crystallization rate; in other cases, the crystallization rate of most regions in the second crystallization section 122 is within the range of the second crystallization rate, while a small portion of the crystallization rate is outside the range of the second crystallization rate, but the overall average crystallization rate of the second crystallization section 122 is still the second crystallization rate.

[0072] The average crystallinity of the first crystallization section 112 can be measured by selecting several sampling points at different locations on the first crystallization section 112 and calculating the average crystallinity of these sampling points. In other words, the average crystallinity of the first crystallization section 112 can be measured using a sampling method. Similarly, the average crystallinity of the second crystallization section 122 can also be measured using a sampling method.

[0073] In addition, X-ray diffraction, differential scanning calorimetry, nuclear magnetic resonance, infrared spectroscopy and other methods can be used to measure the crystallization rate of the crystallized part.

[0074] In some embodiments, the first crystallization section 112 has a first grain size, and the second crystallization section 122 has a second grain size, wherein 5nm ≤ the first grain size < 200nm, and 5nm < the second grain size ≤ 200nm.

[0075] It is understandable that as grain size increases, grain boundaries decrease, carrier scattering within the grain decreases, mobility increases, and conductivity improves. In other words, grain size is positively correlated with conductivity.

[0076] The first grain size can be 5nm, 10nm, 30nm, 50nm, 80nm, 100nm, 130nm, 150nm, 190nm, or 199nm. A first grain size within the above range is moderate, avoiding situations where the first grain size is too small, resulting in poor conductivity of the first crystallized portion 112, leading to insufficient current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, making it difficult to effectively improve the hot spot effect. Conversely, an excessively large first grain size also avoids situations where the first crystallized portion 112 has overly excellent conductivity, resulting in excessive current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, affecting the performance of the back contact battery.

[0077] The second grain size can be 6nm, 10nm, 30nm, 50nm, 80nm, 100nm, 130nm, 150nm, 190nm, or 200nm. A larger second grain size within the above range results in superior conductivity of the second crystallized portion 122, improving the carrier collection efficiency of the second electrode 104 and thus enhancing the performance of the back contact battery.

[0078] It should be noted that the first grain size of the first crystallization section 112 refers to the average grain size of each region in the first crystallization section 112. In some cases, the grain size of each region in the first crystallization section 112 is within the range of the first grain size; in other cases, the grain size of most regions in the first crystallization section 112 is within the range of the first grain size, while a small portion of the grain size is outside the range of the first grain size, but the overall average grain size of the first crystallization section 112 is the first grain size. Similarly, the second grain size of the second crystallization section 122 refers to the average grain size of each region in the second crystallization section 122. In some cases, the grain size of each region in the second crystallization section 122 is within the range of the second grain size; in other cases, the grain size of most regions in the second crystallization section 122 is within the range of the second grain size, while a small portion of the grain size is outside the range of the second grain size, but the overall average grain size of the second crystallization section 122 is the second grain size.

[0079] It should also be noted that, compared to the entire back-contact cell / photovoltaic module, the grain size of the first crystallization section 112 is extremely small, and the number of grains in the first crystallization section 112 is extremely large. Therefore, it is impossible to exhaustively measure all grains in the entire first crystallization section 112. Instead, several sampling points are selected at different locations in the first crystallization section 112, and the average grain size of these sampling points is measured and calculated to obtain the average grain size of the first crystallization section 112. That is, the average grain size of the first crystallization section 112 can be measured using a sampling method. Similarly, the average grain size of the second crystallization section 122 can also be measured using a sampling method.

[0080] In addition, the grain size of the crystallized part can be measured using metallographic microscopes, scanning electron microscopes, transmission electron microscopes, X-ray diffractometers, and other methods.

[0081] In some embodiments, the second crystallization section 122 includes a first sub-crystallization section 1221 and a second sub-crystallization section 1222. The first sub-crystallization section 1221 is located on the second region 140 and also on the sidewall of the first doped semiconductor layer 101 facing the second region 140, and is adjacent to the first crystallization section 112; the second sub-crystallization section 1222 is located on the second region 140 and is adjacent to the first sub-crystallization section 1221, and the second sub-crystallization section 1222 is also electrically connected to the second electrode 104. The crystallinity of the first sub-crystallization section 1221 is less than or equal to the crystallinity of the second sub-crystallization section 1222, and / or the grain size of the first sub-crystallization section 1221 is less than or equal to the grain size of the second sub-crystallization section 1222.

[0082] The first sub-crystallization section 1221 includes a portion of the sidewall of the first doped semiconductor layer 101 facing the second region 140. This portion is used to form a leakage current channel when the back contact battery is abnormally heated or blocked, so as to improve the hot spot effect.

[0083] The second sub-crystallization section 1222 is used for electrical connection with the second electrode 104. Electrical connection between the second sub-crystallization section 1222 and the second electrode 104 actually means that both the second sub-crystallization section 1222 and the second electrode 104 are made of conductive materials, and the second sub-crystallization section 1222 and the second electrode 104 are directly contacted or connected via other conductive materials. Therefore, when the battery is in a power generation state, there is an electrical connection between the second sub-crystallization section 1222 and the second electrode 104.

[0084] When the crystallization rate of the first sub-crystallization section 1221 is equal to the crystallization rate of the second sub-crystallization section 1222, the first sub-crystallization section 1221 and the second sub-crystallization section 1222 can be crystallized by the same crystallization process, which is beneficial to improving the preparation efficiency of the back contact battery.

[0085] When the crystallinity of the first sub-crystallized portion 1221 is less than that of the second sub-crystallized portion 1222, the crystallinity of the second sub-crystallized portion 1222 is greater. This results in a lower sheet resistance and stronger conductivity for the second sub-crystallized portion 1222. Furthermore, since the second sub-crystallized portion 1222 is electrically connected to the second electrode 104, the efficiency of the second electrode 104 in collecting charge carriers can be improved, thereby enhancing the performance of the back contact battery. Conversely, the lower crystallinity of the first sub-crystallized portion 1221 results in a higher sheet resistance and weaker conductivity. This hinders current flow between the entire first doped semiconductor layer 101 and the entire second doped semiconductor layer 102, thus preventing excessive current in the leakage channel between the two layers and ensuring a high photoelectric conversion efficiency for the back contact battery.

[0086] When the grain size of the first sub-crystallization section 1221 is equal to the grain size of the second sub-crystallization section 1222, the first sub-crystallization section 1221 and the second sub-crystallization section 1222 can be crystallized by the same crystallization process, which is beneficial to improving the preparation efficiency of the back contact battery.

[0087] When the grain size of the first sub-crystallized portion 1221 is smaller than the grain size of the second sub-crystallized portion 1222, the grain size of the second sub-crystallized portion 1222 is larger. This results in a smaller sheet resistance and stronger conductivity for the second sub-crystallized portion 1222. Furthermore, since the second sub-crystallized portion 1222 is electrically connected to the second electrode 104, the efficiency of the second electrode 104 in collecting charge carriers can be improved, thereby enhancing the performance of the back contact battery. Conversely, the smaller grain size of the first sub-crystallized portion 1221 results in a larger sheet resistance and weaker conductivity. This hinders current flow between the entire first doped semiconductor layer 101 and the entire second doped semiconductor layer 102, thus preventing excessive current in the leakage channel between the two layers and ensuring a high photoelectric conversion efficiency for the back contact battery.

[0088] Figure 3 This is a partial top view of the second doped semiconductor layer in a back contact battery provided in an embodiment of this disclosure.

[0089] Reference Figures 1 to 3In some embodiments, the second doped semiconductor layer 102 includes a plurality of first sub-crystallized portions 1221 spaced apart along the second direction Y. Compared to a scheme in which the first sub-crystallized portions 1221 are arranged along the entire second direction Y, the plurality of first sub-crystallized portions 1221 spaced apart along the second direction Y results in a relatively small volume ratio between the first sub-crystallized portions 1221 and the second doped semiconductor layer 102. This avoids excessive current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102 due to an excessively large volume ratio between the first sub-crystallized portions 1221 and the second doped semiconductor layer 102, thereby ensuring that the back contact battery has a high photoelectric conversion efficiency.

[0090] It is understandable that the portion located between adjacent first sub-crystallized portions 1221 is the uncrystallized portion of the second doped semiconductor layer 102.

[0091] The first direction X is the alternating arrangement of the first zone 130 and the second zone 140, and the second direction Y can be perpendicular to the first direction X.

[0092] In some embodiments, the second sub-crystallized portion 1222 extends along the second direction Y and is adjacent to a plurality of first sub-crystallized portions 1221. The second sub-crystallized portion 1222 is also electrically connected to the second electrode 104. Thus, the second sub-crystallized portion 1222 is arranged along the entire second direction Y, such that the portion of the second doped semiconductor layer 102 that contacts the second electrode 104 consists entirely of second sub-crystallized portions 1222 with larger crystallinity and / or grain size, which is beneficial for improving the efficiency of the second electrode 104 in collecting charge carriers.

[0093] In some embodiments, the second doped semiconductor layer 102 includes a plurality of first crystallized portions 112 spaced apart along the second direction Y. Compared to a scheme in which the first crystallized portions 112 are arranged along the entire second direction Y, the plurality of first crystallized portions 112 spaced apart along the second direction Y results in a relatively small volume ratio of the first crystallized portions 112 to the second doped semiconductor layer 102. This avoids excessive current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102 due to an excessive volume ratio of the first crystallized portions 112 to the second doped semiconductor layer 102, thereby ensuring that the back contact battery has a high photoelectric conversion efficiency.

[0094] It is understandable that the portion located between adjacent first crystallized portions 112 is the uncrystallized portion of the second doped semiconductor layer 102.

[0095] In some embodiments, the second doped semiconductor layer 102 satisfies: 0.3 ≤ W1 / D1 ≤ 0.9, where W1 is the width of the first crystallized portion 112 along the second direction Y, and D1 is the distance between adjacent first crystallized portions 112 along the second direction Y. For example, W1 / D1 can be 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9. W1 / D1 is positively correlated with the volume ratio of the first crystallized portion 112 and the second doped semiconductor layer 102. When W1 / D1 is within the above range, it can prevent excessively large W1 / D1 from causing excessively large current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, affecting the performance of the back contact battery. It can also prevent excessively small W1 / D1 from causing excessively small current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, making it difficult to effectively improve the hot spot effect.

[0096] In some embodiments, the width W1 of the first crystallized portion 112 along the second direction Y is 50 μm to 5000 μm, for example, 50 μm, 100 μm, 500 μm, 1000 μm, 2000 μm, 3000 μm, 4000 μm, or 5000 μm. The width W1 of the first crystallized portion 112 being within the above range ensures that the leakage current of the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor is moderate, which can improve the hot spot effect and does not excessively affect the performance of the back contact battery.

[0097] The spacing D1 between adjacent first crystallized portions 112 is 20μm to 5000μm, for example, 20μm, 50μm, 100μm, 500μm, 1000μm, 2000μm, 3000μm, 4000μm, or 5000μm. When the spacing D1 between adjacent first crystallized portions 112 is within the above range, the leakage current of the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor is moderate, which can improve the hot spot effect and will not excessively affect the performance of the back contact battery.

[0098] In some embodiments, the width of the first sub-crystallized portion 1221 along the second direction Y is equal to the width of the first crystallized portion 112 along the second direction. The spacing between adjacent first sub-crystallized portions 1221 along the second direction Y is equal to the spacing between adjacent first crystallized portions 112 along the second direction Y.

[0099] In some embodiments, the second doped semiconductor layer 102 further includes an amorphous portion 132, which is located on the side of the first doped semiconductor layer 101 facing away from the substrate 100 and adjacent to the first crystallized portion 112. The amorphous portion 132 is the uncrystallized portion of the second doped semiconductor layer 102. Compared to the first crystallized portion 112 and the second crystallized portion 122, the amorphous portion 132 has a larger sheet resistance, which can impede the conduction of current between the entire first doped semiconductor layer 101 and the entire second doped semiconductor layer 102. This avoids excessive current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, thereby ensuring that the back contact battery has a high photoelectric conversion efficiency.

[0100] The crystallinity of the amorphous portion 132 can be 0%.

[0101] In some embodiments, the back contact battery satisfies: L2 / L1≥0.15, where L1 is the sum of the length of the amorphous portion 132 along the first direction X and the length of the first crystallized portion 112 along the first direction X, and L2 is the length of the first crystallized portion 112 along the first direction X.

[0102] Along the first direction X, L2 / L1 is the ratio of the length of the first crystallized portion 112 to the length of the second doped semiconductor layer 102 located on the first region 130, and L2 / L1 is positively correlated with the length of the first crystallized portion 112.

[0103] L2 / L1 can be 0.15, 0.2, 0.5, 0.7, 0.9, or 0.99. A ratio of L2 / L1 within the above range is considered appropriate. An excessively large L2 / L1 can prevent excessive current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, thus affecting the performance of the back contact battery. Conversely, an excessively small L2 / L1 can prevent insufficient current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, making it difficult to effectively improve the hot spot effect.

[0104] In some embodiments, 30μm≤L1≤150μm, 4.5μm≤L2≤150μm.

[0105] L1 can be 30μm, 50μm, 80μm, 100μm, 120μm or 150μm.

[0106] L2 can be 4.5μm, 5μm, 10μm, 30μm, 50μm, 80μm, 100μm, 120μm, or 150μm. A value within the above range indicates a suitable L2 size. An excessively large L2 can prevent excessive current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, thus affecting the performance of the back contact battery. Conversely, an excessively small L2 can prevent insufficient current in the leakage channel between the first doped semiconductor layer 101 and the second doped semiconductor layer 102, making it difficult to effectively improve the hot spot effect.

[0107] In some embodiments, the thickness of the second doped semiconductor layer 102 is 15 nm to 40 nm, for example, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, or 40 nm. The thickness of the second doped semiconductor layer 102 is within the above range, and the moderate thickness facilitates the second electrode 104 in collecting charge carriers through the second doped semiconductor layer 102.

[0108] In some embodiments, the back contact battery further includes a conductive layer 105, which is located on the surface of the second crystallization portion 122 away from the substrate 100 and is electrically connected to the second electrode 104.

[0109] The conductive layer 105 is used to reduce the contact resistance between the second electrode 104 and the second crystallization section 122, so as to improve the efficiency of the second electrode 104 in collecting charge carriers.

[0110] The material of the conductive layer 105 can be TCO (Transparent Conductive Oxide).

[0111] In some embodiments, the conductive layer 105 covers the second sub-crystallized portion 1222 and partially covers the first sub-crystallized portion 1221. Thus, the contact area between the conductive layer 105 and the second crystallized portion 122 is large, allowing the conductive layer 105 to effectively reduce the contact resistance between the second electrode 104 and the second crystallized portion 122, thereby improving the performance of the back contact battery.

[0112] In some embodiments, the second doped semiconductor layer 102 satisfies: 0.1≤L4 / L3≤0.9; where L3 is the length of the first sub-crystallized portion 1221 along the first direction X, and L4 is the length of the portion of the conductive layer 105 that is stacked with the first sub-crystallized portion 1221 along the first direction X.

[0113] L4 / L3 can be 0.1, 0.3, 0.5, 0.7 or 0.9.

[0114] In some embodiments, 5μm≤L3≤100μm, where L3 can be 5μm, 10μm, 30μm, 50μm, 80μm, or 100μm.

[0115] In some embodiments, the back contact battery further includes a conductive film 106, which is located on the surface of the first doped semiconductor layer 101 away from the substrate 100 and is electrically connected to the first electrode 103.

[0116] The conductive film 106 is used to reduce the contact resistance between the first electrode 103 and the first doped semiconductor layer 101, so as to improve the efficiency of the first electrode 103 in collecting charge carriers.

[0117] The first electrode 103 is electrically connected to the first doped semiconductor layer 101, and the first electrode 103 is electrically connected to the conductive film 106. The relevant explanations regarding the electrical connection between the second sub-crystallization section 1222 and the second electrode 104 mentioned above can be referred to, and will not be repeated here.

[0118] The material of conductive film 106 can also be TCO.

[0119] In some embodiments, the back contact battery further includes a first passivation layer 107 and a second passivation layer 108. The first passivation layer 107 is located between the first doped semiconductor layer 101 and the substrate 100; the second passivation layer 108 is located between the second doped semiconductor layer 102 and the substrate 100, and also between the second doped semiconductor layer 102 and the first doped semiconductor layer 101.

[0120] The first passivation layer 107 is used to saturate the dangling bonds of the second surface 120, reduce the defect state density of the second surface 120, reduce the recombination centers of the second surface 120 to reduce the carrier recombination rate, and also to form band bending to achieve selective carrier transport, thereby improving the efficiency of the first electrode 103 in collecting carriers.

[0121] The material of the first passivation layer 107 can be silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, magnesium fluoride, or hydrogenated amorphous silicon.

[0122] The second passivation layer 108 is used to saturate the dangling bonds of the second surface 120, reduce the defect state density of the second surface 120, reduce the recombination centers of the second surface 120 to reduce the carrier recombination rate, and also to form band bending to achieve selective carrier transport, thereby improving the efficiency of the second electrode 104 in collecting carriers.

[0123] The material of the second passivation layer 108 can be amorphous silicon, hydrogenated amorphous silicon, intrinsic amorphous silicon, doped amorphous silicon, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0124] The second passivation layer 108 includes a sidewall portion (not identified) located on the sidewall of the first doped semiconductor layer 101 facing the second region 140. A portion of the first sub-crystallized portion 1221 is located on the sidewall of the sidewall portion away from the first passivation layer 107.

[0125] In some embodiments, the back contact battery further includes a third passivation layer 109, which is located on the first surface 110.

[0126] The third passivation layer 109 is used to passivate defects on the first surface 110, reduce the defect state density of the first surface 110, and reduce the recombination of photogenerated carriers on the first surface 110, thereby improving the open-circuit voltage and efficiency of the back contact cell.

[0127] The material of the third passivation layer 109 can be one of silicon oxide, aluminum oxide, silicon nitride, and silicon oxynitride.

[0128] The third passivation layer 109 can be a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, the materials of different layers can be different from each other, or some layers can be made of the same material but different from the materials of other layers. For example, the third passivation layer 109 can be a multi-layer structure of silicon nitride and aluminum oxide layers.

[0129] Accordingly, this disclosure also provides a stacked battery including the back contact battery described in any of the above embodiments. It should be noted that the parts that are the same as or corresponding to the foregoing embodiments can be referred to the corresponding descriptions of the foregoing embodiments, and will not be repeated hereafter.

[0130] Figure 4 This is a schematic diagram of a stacked battery provided in an embodiment of the present disclosure.

[0131] refer to Figure 4 The stacked battery includes a bottom cell 200 and a perovskite cell 201. The bottom cell 200 is the back contact cell in the aforementioned embodiment; the perovskite cell 201 is located on one side of the bottom cell 200.

[0132] In some embodiments, the perovskite solar cell 201 may include: a first transport layer, a perovskite substrate, a second transport layer, a transparent conductive layer, and an antireflection layer stacked together. The first transport layer is directly opposite the base cell 200.

[0133] In some examples, the first transport layer can be one of an electron transport layer and a hole transport layer, and the second transport layer can be the other of an electron transport layer and a hole transport layer.

[0134] In some embodiments, the bandgap width of the perovskite cell 201 is wider than that of the base cell 200. Therefore, stacking the perovskite cell 201 on top of the base cell 200 can give the stacked cell a wider spectral response range, thereby maximizing the utilization of solar energy and improving the efficiency of the cell.

[0135] In some embodiments, the stacked cell may further include an intermediate connecting layer (not shown) connected between the bottom cell 200 and the perovskite cell 201.

[0136] In some embodiments, the intermediate connecting layer is generally a tunnel junction or a very thin metal or transparent electrode composite layer. Optionally, the intermediate connecting layer can be a transparent conductive oxide, which has good optoelectronic properties, high photon transmittance and high conductivity, thereby enabling the perovskite cell 201 and the bottom cell 200 to maintain good ohmic contact.

[0137] Accordingly, another aspect of this disclosure provides a photovoltaic module, which includes the back-contact cell or the tandem cell described in any of the above embodiments. It should be noted that the parts that are the same as or corresponding to the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated hereafter.

[0138] Figure 5 This is a partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in an embodiment of this disclosure; Figure 6 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in an embodiment of this disclosure.

[0139] refer to Figure 5 and Figure 6 The photovoltaic module includes: a battery string, an encapsulating film 301, and a cover plate 302, and is formed by connecting multiple back-contact batteries 300 as in any of the above embodiments, or by connecting multiple stacked batteries as in the above embodiments; the encapsulating film 301 is used to cover the surface of the battery string; the cover plate 302 is used to cover the surface of the encapsulating film 301 that is away from the battery string.

[0140] In some embodiments, the back contact battery 300 is electrically connected in a single piece or in multiple pieces to form multiple battery strings, and the multiple battery strings are electrically connected in series and / or parallel. The back contact battery 300 can be a single piece of battery or a piece of battery, and a piece of battery refers to a battery formed by cutting a complete single piece of battery.

[0141] Multiple back-contact batteries 300 can be electrically connected by solder strip 303.

[0142] In some embodiments, the encapsulating film 301 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the first and second surfaces of the back contact battery 300, and the second encapsulating layer covers the other of the first and second surfaces of the back contact battery 300. Specifically, at least one of the first and second encapsulating layers can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film; or, at least one of the first and second encapsulating layers can also be an EP film, EPE film, or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0143] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 301.

[0144] In some embodiments, the cover plate 302 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 302 facing the encapsulating film 301 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 302 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0145] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A back-contact battery, characterized in that, include: A substrate, the substrate comprising opposing first and second surfaces, the first surface comprising a first region and a second region alternately distributed along a first direction; A first doped semiconductor layer is located on the first region; The second doped semiconductor layer has a different conductivity type than the doped elements in the first doped semiconductor layer. The second doped semiconductor layer includes a first crystallized portion and a second crystallized portion. The first crystallized portion is located on the first region and on the side of the first doped semiconductor layer away from the substrate. The second crystallized portion is located on the second region and adjacent to the first crystallized portion. The second doped semiconductor layer includes a plurality of first crystallized portions spaced apart along a second direction. Wherein, the crystallization rate of the first crystallization part is less than the crystallization rate of the second crystallization part, and / or, the grain size of the first crystallization part is less than the grain size of the second crystallization part; A first electrode is located on the first region and is electrically connected to the first doped semiconductor layer. The second electrode is located on the second region and is electrically connected to the second crystallization part.

2. The back contact battery according to claim 1, characterized in that, The second crystallization section includes: The first sub-crystallization section is located on the second region, and is also located on the sidewall of the first doped semiconductor layer facing the second region, and is adjacent to the first crystallization section; The second sub-crystallization section is located on the second region and is adjacent to the first sub-crystallization section. The second sub-crystallization section is also electrically connected to the second electrode. Wherein, the crystallization rate of the first sub-crystallization part is less than or equal to the crystallization rate of the second sub-crystallization part, and / or, the grain size of the first sub-crystallization part is less than or equal to the grain size of the second sub-crystallization part.

3. The back contact battery according to claim 2, characterized in that, The second doped semiconductor layer includes a plurality of first sub-crystallized portions spaced apart along a second direction.

4. The back contact battery according to claim 3, characterized in that, The second sub-crystallization portion extends along the second direction and is adjacent to a plurality of the first sub-crystallization portions. The second sub-crystallization portion is also electrically connected to the second electrode.

5. The back contact battery according to claim 1, characterized in that, The second doped semiconductor layer satisfies: 0.3≤W1 / D1≤0.9, where W1 is the width of the first crystallized portion along the second direction, and D1 is the distance between adjacent first crystallized portions along the second direction.

6. The back contact battery according to claim 1, characterized in that, Along the second direction, the width of the first crystallized portion is 50μm to 5000μm, and the spacing between adjacent first crystallized portions is 20μm to 5000μm.

7. The back contact battery according to claim 1, characterized in that, The first crystallized portion has a first crystallization rate, and the second crystallized portion has a second crystallization rate, wherein 20% ≤ first crystallization rate < 70%, and 40% ≤ second crystallization rate ≤ 70%.

8. The back contact battery according to claim 1, characterized in that, The first crystallized part has a first grain size, and the second crystallized part has a second grain size, wherein 5nm ≤ first grain size < 200nm, and 5nm < second grain size ≤ 200nm.

9. The back contact battery according to claim 1, characterized in that, The second doped semiconductor layer further includes: The amorphous portion is located on the side of the first doped semiconductor layer away from the substrate and is adjacent to the first crystallized portion.

10. The back contact battery according to claim 9, characterized in that, The back contact battery satisfies: L2 / L1≥0.15, where L1 is the sum of the length of the amorphous portion along the first direction and the length of the first crystallized portion along the first direction, and L2 is the length of the first crystallized portion along the first direction.

11. The back contact battery according to claim 10, characterized in that, 30μm≤L1≤150μm, 4.5μm≤L2≤150μm.

12. The back contact battery according to claim 1, characterized in that, The thickness of the second doped semiconductor layer is 15nm~40nm.

13. The back contact battery according to claim 1, characterized in that, The back contact battery also includes: A conductive layer is located on the surface of the second crystallized portion away from the substrate and is electrically connected to the second electrode.

14. A stacked battery, characterized in that, include: The bottom battery is a back contact battery as described in any one of claims 1 to 13; A perovskite solar cell, wherein the perovskite solar cell is located on one side of the bottom solar cell.

15. A photovoltaic module, characterized in that, include: The battery string is formed by connecting a plurality of back-contact batteries as described in any one of claims 1 to 13, or by connecting a plurality of stacked batteries as described in claim 14; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

Images