Back contact battery and photovoltaic module

Abstract

The invention discloses a back contact cell and a photovoltaic module, relates to the technical field of photovoltaic, and aims to change the transmission path of light in the surface, close to a spacer region, of a first region and / or a second region in the back contact cell through an island-shaped passivation structure and increase the double-sided rate of the back contact cell. The back contact battery comprises a semiconductor substrate, a first doped semiconductor layer, a second doped semiconductor layer and an island-shaped passivation structure. The first surface of the semiconductor substrate includes a first region, a second region and a spacer region. The first doped semiconductor layer has a first boundary proximate the spacer region. The conductive types of the second doped semiconductor layer and the first doped semiconductor layer are opposite, and the second doped semiconductor layer is provided with a second boundary close to the interval region. The island passivation structure is disposed on the semiconductor substrate. Wherein the at least one island-shaped passivation structure is at least partially located between the first boundary and the first side wall; and / or at least one island-shaped passivation structure is at least partially located between the second boundary and the second side wall.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular, to a back-contact battery and a photovoltaic module. Background Art

[0002] A back-contact battery refers to a solar cell in which the light-facing surface of the cell has no electrodes, and the positive and negative electrodes are both disposed on the backlight side of the cell, thereby reducing the shielding of the electrodes on the cell and increasing the short-circuit current of the cell, and improving the energy conversion efficiency of the cell.

[0003] However, the light utilization rate on the back side of the existing back-contact battery is relatively low, which is not conducive to improving the bifaciality of the back-contact battery. Summary of the Invention

[0004] The purpose of the present application is to provide a back-contact battery and a photovoltaic module, which are used to change the transmission path of light at the surface of the first region and / or the second region close to the spacer region in the back-contact battery through an island-shaped passivation structure, which is conducive to making more light refract into the battery from the first surface, improving the light utilization rate on the back side of the back-contact battery, and increasing the bifaciality of the back-contact battery.

[0005] To achieve the above object, in a first aspect, the present application provides a back-contact battery, which includes: a semiconductor substrate, a first doped semiconductor layer, a second doped semiconductor layer, and an island-shaped passivation structure. The semiconductor substrate has opposite first and second surfaces. The first surface includes an alternately spaced first region and a second region, and a spacer region located between the first region and the second region. Along the direction from the first surface to the second surface, the surface of the spacer region is recessed into the semiconductor substrate relative to the surface of the first region to form a groove structure. The groove structure has a first sidewall close to the first region and a second sidewall close to the second region. The first doped semiconductor layer is disposed on the first region, and the first doped semiconductor layer has a first boundary close to the spacer region. The second doped semiconductor layer is disposed on the second region, and the second doped semiconductor layer has a conductivity type opposite to that of the first doped semiconductor layer. The second doped semiconductor layer has a second boundary close to the spacer region. The island-shaped passivation structure is disposed on the semiconductor substrate. Wherein, at least one island-shaped passivation structure is at least partially located between the first boundary and the first sidewall; and / or, at least one island-shaped passivation structure is at least partially located between the second boundary and the second sidewall.

[0006] When the back-contact battery is in the working state, the first doped semiconductor layer and the second doped semiconductor layer can effectively shunt and collect carriers, which is beneficial to the formation of photocurrent. The island-shaped passivation structure has a passivation function, which can passivate the surface of the semiconductor substrate in the area with the island-shaped passivation structure, reduce the number of defects on the area surface, and reduce the carrier recombination rate. In addition, the island-shaped passivation structure can change the transmission path of incident light (such as increasing the reflection path of incident light), which is beneficial to more incident light refracting into the battery, increasing the absorption ratio of incident light, and increasing the bifaciality of the back-contact battery. The island-shaped passivation structure is not a part of the semiconductor substrate, and it is an additional passivation structure arranged on the semiconductor substrate and having an island shape. Taking the example that at least one island-shaped passivation structure is at least partially located between the first boundary and the first sidewall: there may be a certain height difference between the surface of the island-shaped passivation structure facing away from the semiconductor substrate and the local surface of the semiconductor substrate located between the first boundary and the first sidewall, or there are differences in materials between the island-shaped passivation structure and the semiconductor substrate, so that the island-shaped passivation structure can reflect or refract the incident light on the first side of the back-contact battery, change the transmission path of incident light (such as increasing the reflection path of incident light), which is beneficial to more incident light refracting into the battery, increasing the absorption ratio of incident light, and increasing the bifaciality of the back-contact battery.

[0007] As a possible implementation solution, the first boundary has a first sub-boundary located in the first region and spaced from the first sidewall along the width direction of the spacer region, and an island-shaped passivation structure is arranged between at least one first sub-boundary and the first sidewall. And / or, the second boundary has a second sub-boundary located in the second region and spaced from the second sidewall along the width direction of the spacer region, and an island-shaped passivation structure is arranged between at least one second sub-boundary and the second sidewall.

[0008] Taking the example where the first boundary has a first sub-boundary located within the first region and spaced from the first sidewall of the groove structure along the width direction of the spacer region for illustration: When the first boundary further includes the first sub-boundary, along the width direction of the spacer region, between the portion of the first doped semiconductor layer corresponding to the first sub-boundary and the second doped semiconductor layer, there is not only the spacer region, but also because the first sub-boundary is spaced from the first sidewall of the groove structure. In other words, the portion of the first doped semiconductor layer corresponding to the first sub-boundary is indented into the first region relative to the first sidewall of the groove structure. Therefore, the distance between part of the first doped semiconductor layer and the second doped semiconductor layer can be increased, further reducing the leakage risk between the two. Additionally, the island-shaped passivation structure is disposed on the portion of the first region not directly covered by the first doped semiconductor layer, which can reduce the quality and precision requirements for forming the conductive electrode on the first doped semiconductor layer due to the presence of the island-shaped passivation structure. At the same time, the presence of the island-shaped passivation structure can passivate the local surface in the first region of the semiconductor substrate where the surface defects not directly covered by the first doped semiconductor layer are relatively numerous and the passivation requirement is relatively high, facilitating the reduction of the carrier recombination rate on this local surface and improving the conversion efficiency of the back contact battery. The second boundary has a second sub-boundary located within the second region and spaced from the second sidewall along the width direction of the spacer region. An island-shaped passivation structure is provided between at least one second sub-boundary and the second sidewall. The functions and effects of the island-shaped passivation structure refer to those of the island-shaped passivation structure of the first sub-boundary and will not be elaborated here.

[0009] As a possible implementation solution, the portion in the first region close to the first sidewall and not directly covered by the first doped semiconductor layer is a platform region, and / or the portion in the second region close to the second sidewall and not directly covered by the second doped semiconductor layer is a platform region. Wherein, the platform region includes a plane substantially parallel to the first surface. At least one island-shaped passivation structure is disposed on the plane included in the platform region.

[0010] The platform region includes a plane substantially parallel to the first surface. At this time, the surface of the portion in the first region of the semiconductor substrate not directly covered by the first doped semiconductor layer and / or the portion in the second region not directly covered by the second doped semiconductor layer (i.e., the platform region) is relatively flat. On the one hand, as a transition region between the first region or the second region and the spacer region, it can effectively reduce the leakage risk. And by disposing at least one island-shaped passivation structure in part of the platform region, the surface of the platform region provided with the island-shaped passivation structure can be passivated, reducing the number of surface defects in the region and the carrier recombination rate. On the other hand, the plane of the platform region increases the light absorption area, promotes the diversification of the light absorption surface morphology, and by disposing at least one island-shaped passivation structure in part of the platform region, and the island-shaped passivation structure enhances the light absorption, comprehensively improving the light utilization rate of the back contact battery.

[0011] As a possible implementation, in the width direction of the spacer region, the width of the plane included in at least one platform region is less than or equal to 1 μm.

[0012] Taking the part in the first region that is close to the first sidewall and not directly covered by the first doped semiconductor layer as a platform region as an example for illustration: It can be understood that the larger the width of the plane included in the platform region, the larger the distance between the corresponding part of the first doped semiconductor layer in the platform region and the spacer region, and the smaller the area ratio of the first doped semiconductor layer on the first region. Therefore, when the width of the plane included in at least one platform region is within the above range, it is beneficial to improve the bifaciality and passivation effect of the back contact cell through the island-shaped passivation structure, while enabling the first doped semiconductor layer to have a larger area ratio on the first region, thereby facilitating the first doped semiconductor layer to have a higher field passivation effect and carrier collection ability, and further facilitating the back contact cell to have a higher conversion efficiency. The part in the second region that is close to the second sidewall and not directly covered by the second doped semiconductor layer is a platform region, and the functions and effects of the width of the plane included in at least one platform region being less than or equal to 1 μm refer to the functions and effects of the width of the plane included in the platform region in the first region being less than or equal to 1 μm, and will not be elaborated here.

[0013] As a possible implementation, when there is a platform region in the first region, at least one platform region further includes a third sidewall that is away from the first sidewall and continuous with the plane. And / or, when there is a platform region in the second region, at least one platform region further includes a third sidewall that is away from the second sidewall and continuous with the plane. Wherein, the third sidewall is perpendicularly arranged with respect to the plane, or the third sidewall is obliquely arranged with respect to the plane.

[0014] Taking the first region having a platform region and the platform region further including a third sidewall as an example for illustration: The platform region further including a third sidewall continuous with the plane indicates that along the direction from the first surface to the second surface, the plane is recessed into the semiconductor substrate with respect to the surface of the region directly covered by the first doped semiconductor layer in the first region, which can reduce the height change amplitude between the bottom surface of the groove structure and the surface of the region with a larger height in the first region, facilitate the formation quality and coating of the surface passivation layer at the junction of the first region and the spacer region, reduce the carrier recombination rate at the junction of the first region and the spacer region, enhance the diversity of the light absorption surface morphology, and improve the light utilization rate of the back contact cell. The application principle of the beneficial effects of the second region having a platform region and the platform region further including a third sidewall can refer to the application principle of the beneficial effects of the first region having a platform region and the platform region further including a third sidewall in the foregoing text, and will not be elaborated here.

[0015] As a possible implementation scheme, at least one island-shaped passivation structure also extends from the plane to at least a portion of the third side wall. In this case, it is beneficial to increase the passivation contact area of ​​the island-shaped passivation structure on the side of the first surface, and improve the passivation effect of the island-shaped passivation structure. In addition, it is also possible to increase the surface area of ​​the island-shaped passivation structure on the side away from the semiconductor substrate, which is beneficial to enhance the light trapping effect of the first surface provided with the island-shaped passivation structure.

[0016] As a possible implementation solution, along the thickness direction of the semiconductor substrate, the height of the third side wall is greater than or equal to 0.05 μm and less than or equal to 8 μm.

[0017] The height of the third sidewall is within the above range, which is conducive to preventing the height variation between the bottom surface of the groove structure and the surface of the area with a larger height in the first region (and / or the second region) from being large due to the small height of the third sidewall, and is conducive to further improving the passivation effect of the surface passivation layer at the junction of the first region and the spacing region, and / or at the junction of the second region and the spacing region. In addition, it can also prevent the etching amount of the part of the semiconductor substrate corresponding to the platform area from being large due to the large height of the second sidewall, which is conducive to making the part of the semiconductor substrate corresponding to the platform area have a larger light absorption depth, which is conducive to improving the light utilization rate of the semiconductor substrate, and further improving the conversion efficiency of the back contact battery.

[0018] As a possible implementation scheme, when the first region has a platform region, part of the first boundary also extends above the plane included in the platform region, and the first doped semiconductor layer and the island-shaped passivation structure are distributed at intervals. And / or, when the second region has a platform region, part of the second boundary also extends above the plane included in the platform region, and the second doped semiconductor layer and the island-shaped passivation structure are distributed at intervals.

[0019] Taking the example where the first region has a platform region and a part of the first boundary also extends above the plane included in the platform region: Although the distance between this part of the first boundary and the second doped semiconductor layer is relatively small, the part of the first doped semiconductor layer corresponding to this part of the first boundary can reflect some of the light emitted from the plane and / or reflected by the outer surface of the island-shaped passivation structure, so that some of the light can re-enter the semiconductor substrate, further improving the light utilization rate of the back contact battery. In addition, the first doped semiconductor layer and the island-shaped passivation structure are spaced apart, which is conducive to the transmission of light between the outer surface of the island-shaped passivation structure and the inner surface of the part of the first doped semiconductor layer extending above the plane, conducive to changing the transmission path of the incident light under the action of these two parts, conducive to more incident light refracting into the battery, increasing the absorption ratio of the incident light, and further improving the bifaciality of the back contact battery. Moreover, when the island-shaped passivation structure includes a doped semiconductor passivation part with a conductivity type opposite to that of the first doped semiconductor layer, the spaced distribution of the first doped semiconductor layer and the island-shaped passivation structure is also conducive to reducing the leakage risk between the two, and conducive to the back contact battery having a high conversion efficiency. The application principle of the beneficial effects of the second region having a platform region and a part of the second boundary also extending above the plane included in the platform region can refer to the application principle of the beneficial effects of the first region having a platform region and a part of the first boundary also extending above the plane included in the platform region described above, and will not be elaborated here.

[0020] As a possible implementation, when a part of the first boundary also extends above the plane included in the platform region, along the thickness direction of the semiconductor substrate, the distance between the first doped semiconductor layer and the island-shaped passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm. And / or, when a part of the second boundary also extends above the plane included in the platform region, along the thickness direction of the semiconductor substrate, the distance between the second doped semiconductor layer and the island-shaped passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm.

[0021] Taking the distance between the first doped semiconductor layer and the island-shaped passivation structure within the above range as an example for illustration: it is beneficial for light to be effectively transmitted between the outer surface of the island-shaped passivation structure and the inner surface of the part where the first doped semiconductor layer extends above the plane, enabling these two parts to effectively cooperate in changing the transmission path of the incident light and further increasing the absorption ratio of the incident light. Additionally, due to the same other factors, when the distance between the first doped semiconductor layer and the island-shaped passivation structure becomes larger, the etching amount of the part of the semiconductor substrate corresponding to the platform region is larger. Therefore, the distance between the first doped semiconductor layer and the island-shaped passivation structure within the above range can also make the part of the semiconductor substrate corresponding to the platform region have a larger absorption depth, improving the utilization rate of light by the semiconductor substrate. The application principle of the beneficial effects when the distance between the second doped semiconductor layer and the island-shaped passivation structure is within the above range can refer to the application principle of the beneficial effects when the distance between the first doped semiconductor layer and the island-shaped passivation structure is within the above range as described above, and will not be elaborated here.

[0022] As a possible implementation, when part of the first boundary also extends above the plane included in the platform region, along the width direction of the spacer region, the extension width of the first boundary relative to the third sidewall is less than or equal to 1 μm. And / or, when part of the second boundary also extends above the plane included in the platform region, along the width direction of the spacer region, the extension width of the second boundary relative to the third sidewall is less than or equal to 1 μm.

[0023] Taking the case where part of the first boundary also extends above the plane included in the platform region and the extension width is within the above range as an example for illustration: it can prevent the reflection effect of the extended part of the first doped semiconductor layer on light from being weak due to too small an extension width, which is beneficial for further improving the bifaciality of the back contact battery. The application principle of the beneficial effects when part of the second boundary also extends above the plane included in the platform region and the extension width is within the above range can refer to the application principle of the beneficial effects when part of the first boundary also extends above the plane included in the platform region and the extension width is within the above range as described above, and will not be elaborated here.

[0024] As a possible implementation, the area ratio of at least one island-shaped passivation structure in the platform region is greater than 50%. It is beneficial for the island-shaped passivation structure to have a larger area ratio in the platform region, which is conducive to enhancing the adjustment effect of the island-shaped passivation structure on the light transmission path, facilitating more incident light to be refracted into the battery, increasing the absorption ratio of the incident light, and further improving the bifaciality of the back contact battery.

[0025] As a possible implementation, the first boundary has a first concave-convex alternating structure, and at least part of the boundaries of the concave parts in the first concave-convex alternating structure are first sub-boundaries. And / or, the second boundary has a second concave-convex alternating structure, and at least part of the boundaries of the concave parts in the second concave-convex alternating structure are second sub-boundaries.

[0026] Taking the example where the first boundary has a first concave-convex alternating structure and the boundaries of at least some of the concave portions in the first concave-convex alternating structure are first sub-boundaries: The first doped semiconductor layer is disposed opposite to the first sub-boundary within the first region and at least some of the concave portions in the first concave-convex alternating structure, which is beneficial for making the concave-convex alternating structure presented by the first boundary more matched with the fluctuation change of the indented portion of the first doped semiconductor layer into the first region. It can reduce the etching amount of the semiconductor substrate for making the first boundary of the first doped semiconductor layer, which is beneficial for increasing the light absorption area of the semiconductor substrate and improving the conversion efficiency of the back contact battery. The application principle of the beneficial effect that the second boundary has a second concave-convex alternating structure and the boundaries of at least some of the concave portions in the second concave-convex alternating structure are second sub-boundaries can refer to the application principle of the beneficial effect that the first boundary has a first concave-convex alternating structure and the boundaries of at least some of the concave portions in the first concave-convex alternating structure are first sub-boundaries described above, and will not be elaborated here.

[0027] As a possible implementation, at least some of the convex portions in the first concave-convex alternating structure and / or the second concave-convex alternating structure extend above the groove structure along the width direction of the spacer region.

[0028] The portion of the first doped semiconductor layer and / or the second doped semiconductor layer corresponding to at least some of the convex portions is suspended above the groove structure, which is beneficial for reflecting some of the light emitted from the first surface of the semiconductor substrate back to the semiconductor substrate and being utilized by the semiconductor substrate again, thereby improving the light utilization rate of the back contact battery.

[0029] As a possible implementation, the extension width of at least one convex portion in the first concave-convex alternating structure above the groove structure relative to the first sidewall is less than or equal to 1 μm. And / or, the extension width of at least one convex portion in the second concave-convex alternating structure above the groove structure relative to the second sidewall is less than or equal to 1 μm. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect that in some cases, the first boundary also extends above the plane included in the platform region and the extension width of the first boundary relative to the third sidewall is less than or equal to 1 μm described above, and will not be elaborated here.

[0030] As a possible implementation, along the extension direction of the spacer region, the first sidewall has a third concave-convex alternating structure, and at least some of the convex portions in the third concave-convex alternating structure are staggered with the adjacent convex portions in the first concave-convex alternating structure. And / or, along the extension direction of the spacer region, the second sidewall has a fourth concave-convex alternating structure, and at least some of the convex portions in the fourth concave-convex alternating structure are staggered with the adjacent convex portions in the second concave-convex alternating structure.

[0031] Taking the example that at least some of the convex portions in the third concave-convex alternating structure are alternately distributed with the adjacent convex portions in the first concave-convex alternating structure for illustration: it is beneficial to arrange island-shaped passivation structures on the portions where the convex or concave portions of the third concave-convex alternating structure are alternately distributed with the concave or convex portions of the first concave-convex alternating structure respectively. While increasing the bifaciality rate of the battery by arranging the island-shaped passivation structures, a relatively large area ratio of the first doped semiconductor layer can be achieved on the first region, enhancing the field passivation effect and carrier collection ability of the first doped semiconductor layer. The application principle of the beneficial effects of the alternate distribution of at least some of the convex portions in the third concave-convex alternating structure with the adjacent convex portions in the second concave-convex alternating structure can refer to the application principle of the beneficial effects of the alternate distribution of at least some of the convex portions in the third concave-convex alternating structure with the adjacent convex portions in the first concave-convex alternating structure described above, which will not be elaborated here.

[0032] As a possible implementation, at least one island-shaped passivation structure includes a doped semiconductor passivation portion; and / or, at least one island-shaped passivation structure includes an interface passivation portion; and / or, at least one island-shaped passivation structure includes a doped semiconductor portion and a doped silicon glass portion provided on the side of the doped semiconductor portion away from the semiconductor substrate.

[0033] The island-shaped passivation structure can be formed by at least the doped semiconductor passivation portion, the interface passivation portion, and the doped silicon glass portion, which have good effects and are compatible with the battery manufacturing process. While enabling the island-shaped passivation structure to have a good passivation effect, the yield of the back-contact battery can also be improved. Additionally, the doped semiconductor passivation portion, the interface passivation portion, and the doped silicon glass portion are also materials for manufacturing the back-contact battery. At this time, the manufacturing of the island-shaped passivation structure can be achieved while manufacturing the corresponding structures in the back-contact battery, improving the manufacturing efficiency of the back-contact battery and simplifying the manufacturing process of the back-contact battery.

[0034] As a possible implementation, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material and conduction type of the doped semiconductor portion are the same as those of the second doped semiconductor layer respectively; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material and conduction type of the doped semiconductor portion are the same as those of the first doped semiconductor layer respectively.

[0035] When the material and conductivity type of the doped semiconductor part in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall are respectively the same as the material and conductivity type of the second doped semiconductor layer, the manufacturing of at least one island-shaped passivation structure disposed between the first boundary and the first sidewall can be realized while manufacturing the second doped semiconductor layer, thereby improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process of the back contact battery. The application principle of the beneficial effect of the material and conductivity type of the doped semiconductor part in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall being respectively the same as the material and conductivity type of the first doped semiconductor layer can be referred to in the previous text and will not be repeated here.

[0036] As a possible implementation scheme, the back contact battery also includes a first interface passivation layer arranged between the semiconductor substrate and the first doped semiconductor layer, and a second interface passivation layer arranged between the semiconductor substrate and the second doped semiconductor layer. Among them, in at least one island-shaped passivation structure arranged between the first boundary and the first sidewall, the material of the interface passivation part is the same as the material of the second interface passivation layer; and / or, in at least one island-shaped passivation structure arranged between the second boundary and the second sidewall, the material of the interface passivation part is the same as the material of the first interface passivation layer. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect of at least one island-shaped passivation structure arranged between the first boundary and the first sidewall, in which the material and conductivity type of the doped semiconductor part are respectively the same as the material and conductivity type of the second doped semiconductor layer, which will not be repeated here.

[0037] As a possible implementation scheme, the back contact cell also includes a first doped silicon glass layer disposed on the side of the first doped semiconductor layer away from the semiconductor substrate, and a second doped silicon glass layer disposed on the side of the second doped semiconductor layer away from the semiconductor substrate. The first doped silicon glass layer has the same conductivity type as the first doped semiconductor layer. The second doped silicon glass layer has the same conductivity type as the second doped semiconductor layer. Among them, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material and conductivity type of the doped silicon glass portion are respectively the same as the material and conductivity type of the second doped silicon glass layer; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material and conductivity type of the doped silicon glass portion are respectively the same as the material and conductivity type of the first doped silicon glass layer. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect of the at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, in which the material and conductivity type of the doped semiconductor portion are respectively the same as the material and conductivity type of the second doped semiconductor layer, and will not be repeated here.

[0038] Second aspect, the present application provides a photovoltaic module, which includes a battery string and a packaging layer. The battery string is formed by electrically connecting a plurality of back-contact batteries provided in the first aspect and its various implementation manners; the packaging layer covers the surface of the battery string.

[0039] For the beneficial effects of the second aspect and its various implementation manners in the present application, reference can be made to the analysis of the beneficial effects in the first aspect and its various implementation manners, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0041] Figure 1 is a longitudinal cross-sectional schematic view of the first structure of the back-contact battery provided by the embodiment of the present application;

[0042] Figure 2 is the SEM of the back-contact battery provided by the embodiment of the present application in a partial first boundary portion Figure 1 ;

[0043] Figure 3 is the SEM of the back-contact battery provided by the embodiment of the present application in a partial first boundary portion Figure 2 ;

[0044] Figure 4 is the SEM diagram of the back-contact battery provided by the embodiment of the present application in a partial second boundary portion;

[0045] Figure 5 is a longitudinal cross-sectional schematic view of the second structure of the back-contact battery provided by the embodiment of the present application;

[0046] Figure 6 is a longitudinal cross-sectional schematic view of the third structure of the back-contact battery provided by the embodiment of the present application;

[0047] Figure 7 is a longitudinal cross-sectional schematic view of the fourth structure of the back-contact battery provided by the embodiment of the present application;

[0048] Figure 8 is a longitudinal cross-sectional schematic view of the fifth structure of the back-contact battery provided by the embodiment of the present application;

[0049] Figure 9 is a longitudinal cross-sectional schematic view of the sixth structure of the back-contact battery provided by the embodiment of the present application;

[0050] Figure 10 is a longitudinal cross-sectional schematic view of the seventh structure of the back-contact battery provided by the embodiment of the present application;

[0051] Figure 11 It is a longitudinal sectional view of the eighth structure of the back contact battery provided by the embodiment of the present application;

[0052] Figure 12 It is a longitudinal sectional view of the ninth structure of the back contact battery provided by the embodiment of the present application;

[0053] Figure 13 It is a longitudinal sectional view of the tenth structure of the back contact battery provided by the embodiment of the present application;

[0054] Figure 14 It is a longitudinal sectional view of the eleventh structure of the back contact battery provided by the embodiment of the present application;

[0055] Figure 15 It is a longitudinal sectional view of the twelfth structure of the back contact battery provided by the embodiment of the present application;

[0056] Figure 16 It is a longitudinal sectional view of the thirteenth structure of the back contact battery provided by the embodiment of the present application;

[0057] Figure 17 It is a longitudinal sectional view of the fourteenth structure of the back contact battery provided by the embodiment of the present application;

[0058] Figure 18 It is a longitudinal sectional view of the fifteenth structure of the back contact battery provided by the embodiment of the present application;

[0059] Figure 19 It is an OM of a partial island-shaped passivation structure disposed in the first region or the second region of the back contact battery provided by the embodiment of the present application Figure 1 ;

[0060] Figure 20 It is an OM of a partial island-shaped passivation structure disposed in the first region or the second region of the back contact battery provided by the embodiment of the present application Figure 2 ;

[0061] Figure 21 It is a longitudinal sectional view of the sixteenth structure of the back contact battery provided by the embodiment of the present application;

[0062] Figure 22 It is a longitudinal sectional view of the seventeenth structure of the back contact battery provided by the embodiment of the present application.

[0063] Reference numerals: 11 is a semiconductor substrate, 12 is a first doped semiconductor layer, 13 is a second doped semiconductor layer, 14 is an island-shaped passivation structure, 15 is a first region, 16 is a second region, 17 is a spacer region, 18 is a groove structure, 19 is a first sidewall, 20 is a second sidewall, 21 is a first boundary, 22 is a second boundary, 23 is a platform region, 24 is a plane, 25 is a third sidewall, 26 is a first sub-boundary, 27 is a second sub-boundary, 28 is a first interface passivation layer, 29 is a second interface passivation layer, 30 is a first doped silicon glass layer, and 31 is a second doped silicon glass layer. Detailed implementation manners

[0064] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present application. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present application.

[0065] Schematic diagrams of various structures according to embodiments of the present application are shown in the accompanying drawings. These figures are not drawn to scale, where certain details are enlarged for clearer expression and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0066] In the context of the present application, when a layer / component is referred to as being "on" another layer / component, the layer / component can be directly on the other layer / component, or there can be an intermediate layer / component between them. Additionally, if a layer / component is "on" another layer / component in one orientation, then when the orientation is reversed, the layer / component can be "under" the other layer / component. To make the technical problems, technical solutions, and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely used to explain the present application and are not used to limit the present application.

[0067] Furthermore, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0068] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0069] A solar cell is a device that can convert the light energy of the sun into electrical energy. Specifically, when the solar cell is in a working state, sunlight shines on the semiconductor p-n junction of the solar cell, forming new hole-electron pairs. Under the action of the built-in electric field in the p-n junction, the photo-generated holes flow to the p region, and the photo-generated electrons flow to the n region. After connecting the circuit, an electric current can be generated. Among them, a solar cell with the positive electrode and the negative electrode both on the back of the cell is a back-contact cell. Compared with a double-sided contact solar cell, the front surface of this back-contact cell has no metal electrode blocking, so that the light-facing side of the back-contact cell has a higher light utilization rate. Therefore, the back-contact cell has a higher short-circuit current and photoelectric conversion efficiency, and is one of the technical directions for realizing high-efficiency crystalline silicon cells at present.

[0070] However, in order to improve the formation quality and field passivation effect of the doped semiconductor layer on the back side of the cell, the back surface of the existing back-contact cell is provided with a relatively flat surface. And the light trapping effect of the flat surface is poor, resulting in a low utilization rate of the incident light on the back side of the cell, which is not conducive to improving the bifaciality of the back-contact cell.

[0071] To solve the above technical problems, in a first aspect, an embodiment of the present application provides a back-contact cell. As Figures 1 to 4As shown, the back-contact battery includes: a semiconductor substrate 11, a first doped semiconductor layer 12, a second doped semiconductor layer 13, and an island-shaped passivation structure 14. The semiconductor substrate 11 has opposite first and second surfaces. The first surface includes alternately and spaced-apart first regions 15 and second regions 16, and a spacer region 17 located between the first regions 15 and the second regions 16. Along the direction from the first surface to the second surface, the surface of the spacer region 17 is recessed into the semiconductor substrate 11 relative to the surface of the first region 15 to form a groove structure 18. The groove structure 18 has a first sidewall 19 adjacent to the first region 15 and a second sidewall 20 adjacent to the second region 16. The first doped semiconductor layer 12 is disposed on the first region 15, and the first doped semiconductor layer 12 has a first boundary 21 adjacent to the spacer region 17. The second doped semiconductor layer 13 is disposed on the second region 16, and the second doped semiconductor layer 13 has a conductivity type opposite to that of the first doped semiconductor layer 12. The second doped semiconductor layer 13 has a second boundary 22 adjacent to the spacer region 17. The island-shaped passivation structure 14 is disposed on the semiconductor substrate 11. Wherein, at least one island-shaped passivation structure 14 is at least partially located between the first boundary 21 and the first sidewall 19; and / or, at least one island-shaped passivation structure 14 is at least partially located between the second boundary 22 and the second sidewall 20.

[0072] When the back-contact battery is in a working state, the first doped semiconductor layer and the second doped semiconductor layer can effectively shunt and collect carriers, which is beneficial to the formation of photocurrent. As Figures 1 to 4 shown, the island-shaped passivation structure 14 has a passivation function, which can passivate the surface of the region of the semiconductor substrate 11 where the island-shaped passivation structure 14 is formed, reduce the number of defects on the region surface, and reduce the carrier recombination rate. In addition, the island-shaped passivation structure 14 can change the transmission path of incident light (such as increasing the reflection path of incident light), which is beneficial to more incident light refracting into the battery, improving the incident light absorption ratio, and improving the bifaciality of the back-contact battery. The island-shaped passivation structure 14 does not belong to a part of the semiconductor substrate 11. It is an additional passivation structure disposed on the semiconductor substrate 11 and having an island shape. Taking the example that at least one island-shaped passivation structure 14 is at least partially located between the first boundary 21 and the first sidewall 19: there is a certain height difference between the surface of the island-shaped passivation structure 14 facing away from the semiconductor substrate 11 and the local surface of the semiconductor substrate 11 located between the first boundary 21 and the first sidewall 19, or there are differences in materials between the island-shaped passivation structure 14 and the semiconductor substrate 11, so that the side surface of the island-shaped passivation structure 14 can reflect or refract the incident light on the first surface side of the back-contact battery, change the transmission path of incident light (such as increasing the reflection path of incident light), which is beneficial to more incident light refracting into the battery, improving the incident light absorption ratio, and improving the bifaciality of the back-contact battery.

[0073] In the actual application process, the embodiments of the present application do not specifically limit the material and conductivity type of the semiconductor substrate. Exemplarily, the semiconductor substrate can be a silicon substrate. Alternatively, the semiconductor substrate can also be a substrate made of any semiconductor material such as a silicon-germanium substrate, a germanium substrate, or a gallium arsenide substrate. Secondly, the semiconductor substrate can be an N-type semiconductor substrate, a P-type semiconductor substrate, or an intrinsic semiconductor substrate.

[0074] Secondly, the semiconductor substrate includes opposite first and second surfaces. The first surface of the semiconductor substrate corresponds to the back surface of the back-contact battery, and the second surface of the semiconductor substrate corresponds to the front surface of the back-contact battery. Among them, the distribution of the first region, the second region, and the spacer region on the first surface can be determined according to the distribution of the first doped semiconductor layer and the second doped semiconductor layer formed on the first surface. Specifically, since at least part of the first doped semiconductor layer included in the back-contact battery is disposed on the first region, the distribution range of the first region on the first surface can be determined according to the distribution requirements of the first doped semiconductor layer in the actual application scenario and the anti-leakage requirements between the first doped semiconductor layer and the second doped semiconductor layer. Since the second doped semiconductor layer included in the back-contact battery is disposed on the second region of the first surface, the distribution range of the second region on the first surface can be determined according to the distribution requirements of the second doped semiconductor layer on the semiconductor substrate in the actual application scenario. As for the spacer region, after the distribution ranges of the first region and the second region are confirmed, the distribution range of the spacer region in the first surface is determined.

[0075] It can be understood that one of the first region and the second region generally corresponds to the emitter region, and the other corresponds to the back field region. In terms of the specific conductivity type, one of the first region and the second region generally corresponds to the P region, and the other generally corresponds to the N region.

[0076] As for the shapes of the first region and the second region, they can be set according to actual needs as long as they can be applied to the back-contact battery provided by the embodiments of the present application. For example: the first region and the second region can be alternately distributed in a strip shape, or can be alternately distributed in an interdigitated shape.

[0077] As for the shapes of the first region and the second region, they can be set according to actual needs as long as they can be applied to the back-contact battery provided by the embodiments of the present application. For example: the first region and the second region can be alternately distributed in a strip shape, or can be alternately distributed in an interdigitated shape.

[0078] In terms of the surface topography, as Figure 1 shown, the second surface of the semiconductor substrate 11 can be a polished surface. Alternatively, as Figure 5 shown, the second surface of the semiconductor substrate 11 can also be a textured surface to improve the light trapping effect of the second surface and improve the light utilization rate of the semiconductor substrate 11.

[0079] Regarding the topography of the first surface of the semiconductor substrate, the first surface can be a flat surface, which is conducive to improving the formation quality of the first doped semiconductor layer and the second doped semiconductor layer on the first surface and enhancing the field passivation effect of the two.

[0080] Alternatively, as Figure 5 shown, the surface of the spaced-apart region 17 included in the first surface can be a matte surface to improve the light trapping effect of the spaced-apart region 17 and increase the bifaciality of the back-contact battery.

[0081] In terms of surface height, the surface of the spaced-apart region is recessed into the semiconductor substrate relative to the surface of the first region. The depth of the groove structure in the spaced-apart region can be set according to actual requirements and is not specifically limited herein. In addition, the first sidewall and the second sidewall of the groove structure can be respectively perpendicular to the groove bottom surface or inclined relative to the groove bottom surface. The first sidewall and the second sidewall can be flat surfaces, or can also be matte surfaces formed with texture structures. When the first sidewall and / or the second sidewall is a matte surface, the types and sizes of the texture structures provided on the first sidewall and / or the second sidewall are not specifically limited in the embodiments of the present application.

[0082] Regarding the surface of the second region, the surface of the second region can be flush with the surface of the first region; or, as Figure 6 shown, along the direction from the first surface to the second surface, the surface of the second region 16 can also be recessed into the semiconductor substrate 11 relative to the surface of the first region 15 to reduce the residues remaining after patterning the first doped semiconductor layer 12 on the second region 16 with more patterns, reduce the leakage risk, and be conducive to improving the formation quality of the second doped semiconductor layer 13. In this case, the surface of the second region 16 can be flush with the surface of the spaced-apart region 17; or, as Figure 6 shown, the surface of the second region 16 can also be higher than the groove bottom surface of the spaced-apart region 17. Regarding the depth of the recess of the surface of the second region 16 into the semiconductor substrate 11, it can be set according to actual requirements and is not specifically limited herein.

[0083] In terms of the boundary topography, it is defined that the first sidewall included in the spaced-apart region has a third boundary, and the second sidewall has a fourth boundary. The topography of the third boundary and the fourth boundary can be determined according to the process method used to form the groove structure in the semiconductor substrate in the actual application scenario and is not specifically limited herein.

[0084] Exemplarily, along the extension direction of the spaced-apart region, the third boundary and / or the fourth boundary can be linear. Or, as Figure 2 and Figure 3 shown, the first sidewall 19 can also have a third concave-convex alternating structure, and / or, as Figure 4As shown, the second sidewall 20 may also have a fourth concave-convex alternating structure; the third concave-convex alternating structure and / or the fourth concave-convex alternating structure may be serrated, trapezoidal broken line-shaped, wavy, etc. The third concave-convex alternating structure and / or the fourth concave-convex alternating structure may be a periodic structure with a certain pattern, or an irregular aperiodic structure with microscopic fluctuations and macroscopic roughly concave-convex alternation. The dimensions of the concave and convex portions in the third concave-convex alternating structure and / or the fourth concave-convex alternating structure along the extension direction and the width direction of the interval region 17, as well as the morphologies of the two, can be set according to actual needs and are not specifically limited here.

[0085] For the first doped semiconductor layer and the second doped semiconductor layer, in terms of the conduction type, the present application embodiment does not specifically limit the conduction types of the first doped semiconductor layer and the second doped semiconductor layer, as long as the conduction types of the first doped semiconductor layer and the second doped semiconductor layer are opposite. Specifically, the conduction type of the first doped semiconductor layer may be N-type, and the conduction type of the second doped semiconductor layer is P-type. Or, the conduction type of the first doped semiconductor layer may also be P-type, and the conduction type of the second doped semiconductor layer is N-type.

[0086] In terms of materials, the materials of the first doped semiconductor layer and / or the second doped semiconductor layer may include any semiconductor material such as silicon, silicon-germanium, germanium, or gallium arsenide. In terms of the arrangement form of substances, the crystal phases of the first doped semiconductor layer and / or the second doped semiconductor layer may be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc.

[0087] The materials of the first doped semiconductor layer and the second doped semiconductor layer may be the same or different. For example: the materials of the first doped semiconductor layer and the second doped semiconductor layer may both be doped polysilicon or doped amorphous silicon. Another example: the material of one of the first doped semiconductor layer and the second doped semiconductor layer is doped polysilicon, and the material of the other is doped amorphous silicon.

[0088] In terms of the formation position, as Figure 6 shown, at least part of the first doped semiconductor layer 12 may be directly disposed on the first region 15. Or, as Figure 7As shown, the back-contact battery may further include a first interface passivation layer 28 located between the first doped semiconductor layer 12 and the semiconductor substrate 11. In this case, the passivation contact structure composed of the first interface passivation layer 28 and the first doped semiconductor layer 12 has excellent interface passivation effect, and can achieve selective collection of carriers, reduce the carrier recombination rate in the first region 15 on the first surface of the semiconductor substrate 11, and further improve the photoelectric conversion efficiency of the back-contact battery. The material and thickness of the first interface passivation layer 28 can be set according to the material of the first doped semiconductor layer 12 and actual requirements, and no specific limitation is made here. For example: when the material of the first doped semiconductor layer is doped polysilicon, the first interface passivation layer is a tunneling passivation layer. Another example: when the material of the first doped semiconductor layer includes at least one of doped amorphous silicon, doped microcrystalline silicon and doped nanocrystalline silicon, the first interface passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, an intrinsic nanocrystalline silicon layer or a mixed layer of the above three.

[0089] Regarding the second doped semiconductor layer, the second doped semiconductor layer can be directly disposed on the second region. Or, as Figure 7 As shown, the back-contact battery may further include a second interface passivation layer 29 located between the second doped semiconductor layer 13 and the semiconductor substrate 11. In this case, the passivation contact structure composed of the second interface passivation layer 29 and the second doped semiconductor layer 13 has excellent interface passivation effect, and can achieve selective collection of carriers, reduce the carrier recombination rate in the second region 16 on the first surface of the semiconductor substrate 11, and further improve the photoelectric conversion efficiency of the back-contact battery. The principle of setting the material and thickness of the second interface passivation layer 29 can refer to the principle of setting the material and thickness of the first interface passivation layer 28 described above, and will not be elaborated here.

[0090] In terms of the edge morphology, as Figures 1 to 7 shown, along the width direction of the spacer region 17, the morphology of the first boundary 21 of the first doped semiconductor layer 12 and / or the second boundary 22 of the second doped semiconductor layer 13 can be determined according to the process methods for manufacturing the first doped semiconductor layer 12 and the second doped semiconductor layer 13, and the distribution of the island-shaped passivation structure 14 included in the back-contact battery on the semiconductor substrate 11, and no specific limitation is made here.

[0091] Exemplarily, the first boundary and / or the second boundary can be linear. Or, as Figure 2 and Figure 3 shown, the first boundary 21 can also have a first concavo-convex alternating structure, and / or, as Figure 4As shown, the second boundary 22 can also be in a second concave-convex alternating structure; the first concave-convex alternating structure and / or the second concave-convex alternating structure can be serrated, trapezoidal broken line-shaped, wavy, etc. The first concave-convex alternating structure and / or the second concave-convex alternating structure can be a periodic structure with a certain pattern, or an irregular aperiodic structure with microscopic fluctuations and macroscopic rough concave-convex alternation. The sizes of the concave and convex parts in the first concave-convex alternating structure and / or the second concave-convex alternating structure in the extending direction and the width direction of the spacer region 17, as well as their morphologies, can be set according to actual needs and are not specifically limited here.

[0092] When the first sidewall is in a third concave-convex alternating structure along the extending direction of the spacer region, the corresponding relationship between the concave and convex parts in the first concave-convex alternating structure and the third concave-convex alternating structure can be determined according to the size of the island-shaped passivation structure and the anti-leakage requirements for the back contact battery in the actual application scenario, and is not specifically limited here.

[0093] Exemplarily, as Figure 2 and Figure 3 shown, at least some of the convex parts in the third concave-convex alternating structure are staggered with the adjacent convex parts in the first concave-convex alternating structure. This is beneficial for arranging the island-shaped passivation structure 14 on the parts where the convex or concave parts of the third concave-convex alternating structure are respectively staggered with the concave or convex parts of the first concave-convex alternating structure. While increasing the bifaciality rate of the battery by arranging the island-shaped passivation structure 14, it enables the first doped semiconductor layer 12 to have a large area ratio on the first region 15, enhancing the field passivation effect and carrier collection ability of the first doped semiconductor layer 12. The number and distribution of the convex parts in the third concave-convex alternating structure that are staggered with the adjacent convex parts in the first concave-convex alternating structure can be determined according to the size and distribution of the island-shaped passivation structure 14 located on the first region 15 in the actual application scenario and are not specifically limited here. Of course, there can also be at least some convex parts in the third concave-convex alternating structure that have the same protruding trend as the adjacent convex parts in the first concave-convex alternating structure.

[0094] Exemplarily, as Figure 4 shown, when the second sidewall 20 is in a fourth concave-convex alternating structure, at least some of the convex parts in the fourth concave-convex alternating structure can be staggered with the adjacent convex parts in the second concave-convex alternating structure. The application principle of the beneficial effects in this case can refer to the above text and will not be elaborated here. The number and distribution of the convex parts in the fourth concave-convex alternating structure that are staggered with the adjacent convex parts in the second concave-convex alternating structure can be determined according to the size and distribution of the island-shaped passivation structure 14 located on the second region 16 in the actual application scenario and are not specifically limited here. Of course, there can also be at least some convex parts in the fourth concave-convex alternating structure that have the same protruding trend as the adjacent convex parts in the second concave-convex alternating structure.

[0095] In some cases, such asFigure 2 and Figure 3 As shown in Figure 3 , the first boundary 21 may have a first sub-boundary 26 located within the first region 15 and spaced apart from the first sidewall 19 in the width direction of the spacer region 17. An island-shaped passivation structure 14 is provided between at least one first sub-boundary 26 and the first sidewall 19. And / or, as Figure 4 shown in Figure 4 , the second boundary 22 has a second sub-boundary 27 located within the second region 16 and spaced apart from the second sidewall 20 in the width direction of the spacer region 17. An island-shaped passivation structure 14 is provided between at least one second sub-boundary 27 and the second sidewall 20.

[0096] As Figure 2 and Figure 3 shown in Figure 2 and Figure 3 , taking the first boundary 21 having a first sub-boundary 26 located within the first region 15 and spaced apart from the first sidewall 19 of the groove structure 18 in the width direction of the spacer region 17 as an example: when the first boundary 21 further includes the first sub-boundary 26, in the width direction of the spacer region 17, between the portion of the first doped semiconductor layer 12 corresponding to the first sub-boundary 26 and the second doped semiconductor layer 13, there is not only the spacer region 17, but also because the first sub-boundary 26 is spaced apart from the first sidewall 19 of the groove structure 18, in other words, the portion of the first doped semiconductor layer 12 corresponding to the first sub-boundary 26 is indented into the first region 15 relative to the first sidewall 19 of the groove structure 18. Therefore, the distance between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 can be increased, further reducing the leakage risk between the two. In addition, the island-shaped passivation structure 14 is provided on the portion of the first region 15 that is not directly covered by the first doped semiconductor layer 12, which can reduce the quality and precision requirements for forming a conductive electrode on the first doped semiconductor layer 12 due to the presence of the island-shaped passivation structure 14. At the same time, the presence of the island-shaped passivation structure 14 can passivate the local surface in the first region 15 of the semiconductor substrate 11 where the number of surface defects not directly covered by the first doped semiconductor layer 12 is relatively large and the passivation requirement is relatively high, which is beneficial to reducing the carrier recombination rate of this local surface and improving the conversion efficiency of the back-contact battery.

[0097] The distribution range and position of the first sub-boundary and the second sub-boundary in the first boundary and the second boundary respectively can be determined according to the size and distribution of the island-shaped passivation structures located on the first region and the second region in the actual application scenario, and no specific limitation is made here.

[0098] Exemplarily, as Figure 2 and Figure 3 shown in Figure 2 and Figure 3 , when the first boundary 21 has a first concave-convex alternating structure, the boundary of at least some of the concave portions in the first concave-convex alternating structure may be the first sub-boundary 26; and / or, as Figure 4As shown, when the second boundary 22 has a second concave-convex alternating structure, the boundary of at least some of the concave portions in the second concave-convex alternating structure can be the second sub-boundary 27.

[0099] Taking the first boundary having a first concave-convex alternating structure and the boundary of at least some of the concave portions in the first concave-convex alternating structure being the first sub-boundary as an example: The first doped semiconductor layer is disposed opposite to the first sub-boundary within the first region and at least some of the concave portions in the first concave-convex alternating structure, which is beneficial for making the concave-convex alternating structure presented by the first boundary more matched with the fluctuation change of the indented part of the first doped semiconductor layer into the first region. It can reduce the etching amount of the semiconductor substrate to make the first boundary of the first doped semiconductor layer, which is beneficial for increasing the light absorption area of the semiconductor substrate and improving the conversion efficiency of the back contact battery.

[0100] In the actual application process, such as Figure 2 and Figure 3 As shown, it can be that only the boundaries of some of the concave portions in the first concave-convex alternating structure are the first sub-boundary 26. In this case, there are some concave portion boundaries aligned with the first sidewall 19 of the groove structure 18, or alternatively, there are some concave portion boundaries in the first concave-convex alternating structure extending above the groove structure 18; of course, it can also be that the boundaries of all the concave portions in the first concave-convex alternating structure are the first sub-boundary 26.

[0101] Such as Figure 2 and Figure 3 and Figure 12 As shown, as for the convex portions in the first concave-convex alternating structure, it can be that only at least some of the convex portions extend along the width direction of the spaced region above the groove structure; or, there are some convex portion boundaries in the first concave-convex alternating structure aligned with the first sidewall 19 of the groove structure; or, there are some convex portion boundaries in the first concave-convex alternating structure located within the first region (i.e., there are some convex portion boundaries that are the first sub-boundary 26); of course, it can also be that the boundaries of all the convex portions in the first concave-convex alternating structure extend above the groove structure along the width direction of the spaced region.

[0102] When at least a part of the first doped semiconductor layer corresponding to the convex portions is suspended above the groove structure, it is beneficial for reflecting part of the light emitted from the first surface of the semiconductor substrate back to the semiconductor substrate and being utilized by the semiconductor substrate again, improving the light utilization rate of the back contact battery.

[0103] As for the second concave-convex alternating structure, such as Figure 4As shown, only some of the concave boundaries in the second concave-convex alternating structure can be the second sub-boundaries 27. In this case, some of the concave boundaries are aligned with the second sidewall 20 of the groove structure. Or, some of the concave boundaries in the second concave-convex alternating structure extend above the groove structure. Of course, all of the concave boundaries in the second concave-convex alternating structure can also be the second sub-boundaries 27.

[0104] As Figure 4 shown, as for the convex parts in the second concave-convex alternating structure, at least some of the convex parts can only extend above the groove structure along the width direction of the interval region. Or, some of the convex boundaries in the second concave-convex alternating structure are aligned with the second sidewall 20 of the groove structure. Or, some of the convex boundaries in the second concave-convex alternating structure are located within the second region (that is, some of the convex boundaries are the second sub-boundaries 27). Of course, all of the convex boundaries in the second concave-convex alternating structure can also extend above the groove structure along the width direction of the interval region.

[0105] The application principle of the beneficial effect when at least a part of the second doped semiconductor layer corresponding to at least some convex parts is suspended above the groove structure can refer to the application principle of the beneficial effect when at least a part of the first doped semiconductor layer corresponding to at least some convex parts is suspended above the groove structure as described above, and will not be elaborated here.

[0106] As for the extension width of at least one convex part in the first concave-convex alternating structure relative to the first sidewall above the groove structure, and / or, the extension width of at least one convex part in the second concave-convex alternating structure relative to the second sidewall above the groove structure can be determined according to the requirements for the bifaciality and leakage risk of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0107] Exemplarily, the extension width of at least one convex part in the first concave-convex alternating structure relative to the first sidewall above the groove structure can be less than or equal to 1 μm. For example: the extension width of at least one convex part in the first concave-convex alternating structure relative to the first sidewall above the groove structure can be 5 nm, 10 nm, 100 nm, 200 nm, 300 nm, 500 nm, 800 nm or 1 μm, etc., so as to further improve the bifaciality of the back contact battery while making the back contact battery have a lower leakage risk.

[0108] Exemplarily, the extension width of at least one convex portion in the second concave-convex alternating structure relative to the second sidewall above the groove structure can be less than or equal to 1 μm. For example, the extension width of at least one convex portion in the first concave-convex alternating structure relative to the first sidewall above the groove structure can be 5 nm, 10 nm, 100 nm, 200 nm, 300 nm, 500 nm, 800 nm, or 1 μm, etc., so as to further improve the bifaciality of the back-contact battery while enabling the back-contact battery to have a lower leakage risk.

[0109] Exemplarily, as Figure 2 and Figure 3 shown, the portion in the first region 15 that is close to the first sidewall 19 and is not directly covered by the first doped semiconductor layer 12 is a platform region 23, and / or, as Figure 4 shown, the portion in the second region 16 that is close to the second sidewall 20 and is not directly covered by the second doped semiconductor layer 13 is a platform region 23. It should be noted that the platform region 23 has a broad meaning, specifically referring to a region, that is, the region in the first region 15 that is close to the first sidewall 19 and is not directly covered by the first doped semiconductor layer 12, and / or the region in the second region 16 that is close to the second sidewall 20 and is not directly covered by the second doped semiconductor layer 13.

[0110] As Figures 2 to 4 shown, the platform region 23 can include a plane 24 that is substantially parallel to the first surface. At this time, the surface of the portion in the first region 15 of the semiconductor substrate 11 that is not directly covered by the first doped semiconductor layer 12 and / or the portion in the second region 16 that is not directly covered by the second doped semiconductor layer 13 (i.e., the platform region 23) is relatively flat. On the one hand, as a transition region between the first region 15 or the second region 16 and the spacer region 17, it can effectively reduce the leakage risk, and by providing the island-shaped passivation structure 14 at least in part of the platform region 23, the surface of the platform region 23 provided with the island-shaped passivation structure 14 can be passivated, reducing the number of defects on the region surface and reducing the carrier recombination rate; on the other hand, the plane 24 of the platform region 23 increases the light absorption area, promotes the diversification of the light absorption surface morphology, and by providing the island-shaped passivation structure 14 at least in part of the platform region 23, and the island-shaped passivation structure 14 enhances the light absorption, comprehensively improving the light utilization rate of the back-contact battery. It should be noted that as long as the angle between the plane 24 included in the platform region 23 and the rest of the surface of the first surface is less than or equal to 5°, it can be considered that the plane 24 is substantially parallel to the first surface.

[0111] Alternatively, the platform region includes a plane that forms an angle (greater than 5° and less than the inclination angle of the first sidewall and / or the second sidewall relative to the bottom surface of the groove) with the first surface. Additionally, the surface included in the platform region can be a relatively flat plane or an uneven surface with structures such as a pyramid shape or a hole shape. The topography of the surface included in the platform region can be set according to actual requirements and will not be specifically limited here.

[0112] In terms of the distribution position, when the first boundary has a first concave-convex alternating structure and the first region has a platform region, the platform region can be disposed between at least some of the concave portions and the first sidewall in the first concave-convex alternating structure. Or, as Figure 2 and Figure 3 shown, the platform region 23 can be disposed below at least some of the convex portions in the first concave-convex alternating structure. Or, there is a platform region 23 between the concave portion and the first sidewall 19 in the first concave-convex alternating structure and also below at least some of the convex portions in the first concave-convex alternating structure. The specific distribution of the platform region 23 can be set according to actual requirements and will not be specifically limited here.

[0113] As for the case where the second boundary has a second concave-convex alternating structure and the second region has a platform region, the distribution of the platform region in the second region can refer to the distribution of the platform region in the case where the first boundary has a first concave-convex alternating structure and the first region has a platform region as described above, and will not be elaborated here.

[0114] As Figure 2 and Figure 4 shown, at least one island-shaped passivation structure 14 included in the back-contact battery can be at least partially disposed on the plane 24 included in the platform region 23. In this case, the size of the plane 24 included in the platform region 23 will affect the size of the island-shaped passivation structure 14. Therefore, the size and topography of the plane 24 included in the platform region 23 can be determined according to the size requirements of the island-shaped passivation structure 14 in the actual application scenario and will not be specifically limited here.

[0115] Exemplarily, in the width direction of the spacer region, the width of the plane included in at least one platform region is less than or equal to 1 μm. For example, the width of the plane included in at least one platform region can be 10 nm, 50 nm, 100 nm, 300 nm, 500 nm, 800 nm, 1 μm, etc. In this case, taking the part in the first region that is close to the first sidewall and not directly covered by the first doped semiconductor layer as the platform region as an example for illustration: It can be understood that the larger the width of the plane included in the platform region, the larger the distance between the corresponding part of the first doped semiconductor layer in the platform region and the spacer region, and the smaller the area ratio of the first doped semiconductor layer on the first region. Therefore, when the width of the plane included in at least one platform region is within the above range, it is beneficial to improve the bifaciality and passivation effect of the back contact cell through the island-shaped passivation structure, while enabling the first doped semiconductor layer to have a larger area ratio on the first region, thereby facilitating the first doped semiconductor layer to have a higher field passivation effect and carrier collection ability, and further facilitating the back contact cell to have a higher conversion efficiency.

[0116] In terms of surface height, as Figure 8 and Figure 13 shown, the plane 24 included in the platform region 23 can be flush with the first surface.

[0117] Alternatively, as Figures 9 to 11 and Figures 13 to 15 shown, when there is a platform region 23 in the first region 15, at least one platform region 23 further includes a third sidewall 25 that is away from the first sidewall 19 and continuous with the plane 24; and / or, when there is a platform region 23 in the second region 16, at least one platform region 23 further includes a third sidewall 25 that is away from the second sidewall 20 and continuous with the plane 24. Among them, the third sidewall 25 is perpendicularly arranged with respect to the plane 24, or the third sidewall 25 is inclinedly arranged with respect to the plane 24.

[0118] Taking the case where the first region has a platform region and the platform region further includes a third sidewall as an example for illustration: The platform region further includes a third sidewall that is continuous with the plane, indicating that along the direction from the first surface to the second surface, the plane is recessed into the semiconductor substrate relative to the surface of the region in the first region that is directly covered by the first doped semiconductor layer, which can reduce the height change amplitude between the bottom surface of the groove structure and the surface of the region with a larger height in the first region, facilitate the formation quality and coating of the surface passivation layer at the junction of the first region and the spacer region, reduce the carrier recombination rate at the junction of the first region and the spacer region, enhance the morphological diversity of the light absorption surface, and improve the light utilization rate of the back contact cell.

[0119] When the platform region further includes a third sidewall, as Figure 3 and Figure 4As shown, at least one island-shaped passivation structure 14 may be disposed only on the plane 24 of the platform region 23. Alternatively, as shown in FIG. Figure 2 As shown, at least one island-shaped passivation structure 14 can also extend from the plane 24 to at least a portion of the third side wall 25. In this case, it is beneficial to increase the passivation contact area of ​​the island-shaped passivation structure 14 on the side of the first surface, and improve the passivation effect of the island-shaped passivation structure 14. In addition, the surface area of ​​the island-shaped passivation structure 14 on the side away from the semiconductor substrate 11 can also be increased, which is beneficial to enhance the light trapping effect of the first surface provided with the island-shaped passivation structure 14. The extension range of the island-shaped passivation structure 14 on the third side wall 25 can be set according to actual needs, and is not specifically limited here.

[0120] In the case where the terrace region further includes a third sidewall, a portion of the sidewall of the first doped semiconductor layer and / or the second doped semiconductor layer may be aligned with the third sidewall of at least one adjacent terrace region. Figure 4 , Figures 9 to 11 ,as well as Figures 13 to 15 As shown, part of the first boundary 21 and / or the second boundary 22 can extend above the plane 24. In this case, when part of the sidewall of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 is aligned with the third sidewall 25 of at least one adjacent platform area 23, it is beneficial to increase the distance between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 to be relatively large, which is beneficial to further reduce the risk of leakage between the two. When part of the first boundary 21 and / or the second boundary 22 can extend above the plane 24, take the first region 15 having the platform area 23, and part of the first boundary 21 also extends above the plane 24 included in the platform area 23 as an example: although the distance between this part of the first boundary 21 and the second doped semiconductor layer 13 is relatively small, the part of the first doped semiconductor layer 12 corresponding to this part of the first boundary 21 can reflect part of the light emitted from the plane 24 and / or reflected by the outer surface of the island-shaped passivation structure 14, so that part of the light can re-enter the semiconductor substrate 11, further improving the light utilization rate of the back contact battery.

[0121] In addition, if Figure 3 and Figure 4As shown, the first doped semiconductor layer 12 and the island-shaped passivation structure 14 can be distributed at intervals, which is conducive to the transmission of light between the outer surface of the island-shaped passivation structure 14 and the inner surface of the part of the first doped semiconductor layer 12 extending above the plane 24. It is conducive to changing the transmission path of the incident light under the action of these two parts, and is conducive to refracting more incident light into the battery, improving the absorption ratio of the incident light, and further improving the bifaciality of the back contact battery. Moreover, when the island-shaped passivation structure 14 includes a doped semiconductor passivation part with a conductivity type opposite to that of the first doped semiconductor layer 12, the first doped semiconductor layer 12 and the island-shaped passivation structure 14 are distributed at intervals, which is also conducive to reducing the leakage risk between the two, and is conducive to the back contact battery having a high conversion efficiency. Secondly, when the second boundary 22 extends above the plane 24, the second doped semiconductor layer 13 and the island-shaped passivation structure 14 can also be distributed at intervals. The beneficial effects in this case can refer to the previous text and will not be elaborated here.

[0122] Of course, when the island-shaped passivation structure is provided in the first region, the side walls of the first doped semiconductor layer and the side walls of the island-shaped passivation structure can also be adjacent; and / or, when the island-shaped passivation structure is provided in the second region, the side walls of the second doped semiconductor layer and the side walls of the island-shaped passivation structure can also be adjacent.

[0123] Regarding the height of the above-mentioned third side wall, in the case where part of the first boundary and / or the second boundary also extends above the plane included in the platform region, the spacing between the corresponding doped semiconductor layer and the island-shaped passivation structure, and the extension width of the first boundary and / or the second boundary above the plane can be determined according to the requirements for the bifaciality and leakage risk of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0124] Exemplarily, along the thickness direction of the semiconductor substrate, the height of the third side wall is greater than or equal to 0.05 μm and less than or equal to 8 μm. For example: the height of the third side wall can be 0.05 μm, 0.1 μm, 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 7 μm or 8 μm, etc. When the height of the third side wall is within the above range, it is conducive to preventing a large height change amplitude between the bottom surface of the groove structure and the surface of the region with a larger height in the first region (and / or the second region) due to the small height of the third side wall, and is conducive to further improving the passivation effect at the junction of the first region and the spacer region, and / or at the junction of the second region and the spacer region. In addition, it can also prevent a large etching amount of the part of the semiconductor substrate corresponding to the platform region due to the large height of the second side wall, which is beneficial to making the part of the semiconductor substrate corresponding to the platform region have a large light absorption depth, conducive to improving the light utilization rate of the semiconductor substrate, and further improving the conversion efficiency of the back contact battery.

[0125] Exemplarily, when part of the first boundary also extends above the plane included in the platform region, along the thickness direction of the semiconductor substrate, the spacing between the first doped semiconductor layer and the island-shaped passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm. And / or, when part of the second boundary also extends above the plane included in the platform region, along the thickness direction of the semiconductor substrate, the spacing between the second doped semiconductor layer and the island-shaped passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm. Taking the spacing between the first doped semiconductor layer and the island-shaped passivation structure within the above range as an example for illustration: It is beneficial to the effective transmission of light between the outer surface of the island-shaped passivation structure and the inner surface of the part where the first doped semiconductor layer extends above the plane, enabling these two parts to effectively cooperate in changing the transmission path of the incident light, and further increasing the absorption ratio of the incident light. Additionally, due to other factors being the same, when the spacing between the first doped semiconductor layer and the island-shaped passivation structure becomes larger, the etching amount of the part of the semiconductor substrate corresponding to the platform region is larger. Therefore, the spacing between the first doped semiconductor layer and the island-shaped passivation structure within the above range can also enable the part of the semiconductor substrate corresponding to the platform region to have a larger absorption depth, improving the utilization rate of light by the semiconductor substrate.

[0126] Exemplarily, when part of the first boundary also extends above the plane included in the platform region, along the width direction of the spacer region, the extension width of the first boundary relative to the third sidewall is less than or equal to 1 μm. And / or, when part of the second boundary also extends above the plane included in the platform region, along the width direction of the spacer region, the extension width of the second boundary relative to the third sidewall is less than or equal to 1 μm. Taking the case where part of the first boundary also extends above the plane included in the platform region and the extension width is within the above range as an example for illustration: It can prevent the reflection effect of the extended part of the first doped semiconductor layer on light from being too weak due to an overly small extension width, which is beneficial to further improving the bifaciality of the back-contact battery.

[0127] Exemplarily, when part of the first boundary also extends above the plane included in the platform region, along the width direction of the spacer region, the extension width of the first boundary relative to the third sidewall can be greater than or equal to 10 nm. And / or, when part of the second boundary also extends above the plane included in the platform region, along the width direction of the spacer region, the extension width of the second boundary relative to the third sidewall can be greater than or equal to 10 nm. Taking the case where part of the first boundary also extends above the plane included in the platform region and the extension width is within the above range as an example for illustration: It can prevent the manufacturing process of the back-contact battery from being too difficult due to an overly large extension width, and the reduction in the leakage risk between the extended part of the first doped semiconductor layer and the second doped semiconductor layer is small, which is beneficial to further improving the conversion efficiency and yield of the contact battery.

[0128] For example, when a part of the first boundary also extends above the plane included in the platform region, in the width direction of the spacer region, the extension width of the first boundary relative to the third sidewall can be 10 nm, 20 nm, 50 nm, 100 nm, 200 nm, 500 nm, 800 nm, 1 μm, etc.

[0129] For example, when a part of the second boundary also extends above the plane included in the platform region, in the width direction of the spacer region, the extension width of the second boundary relative to the third sidewall can be 10 nm, 20 nm, 50 nm, 100 nm, 200 nm, 500 nm, 800 nm, 1 μm, etc.

[0130] For the island-shaped passivation structure, in terms of morphology, as Figure 20 shown, at least one island-shaped passivation structure 14 may include a plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner. In this case, it is beneficial to increase the specific surface area of a single island-shaped passivation structure 14, enhance the light trapping effect of the island-shaped passivation structure 14, and further improve the incident light absorption ratio and the bifaciality of the back-contact battery. In this case, the number of dot-shaped passivation parts included in a single island-shaped passivation structure 14, as well as the distribution and morphology of different dot-shaped passivation parts, can be set according to actual needs. The dot-shaped passivation parts can be in morphologies such as approximately regular hemispherical, circular / frustum-shaped, circular / prismatic, or mountain-shaped, or can be irregular shapes with uneven surfaces.

[0131] Alternatively, as Figures 2 to 4 shown, at least one island-shaped passivation structure 14 may also be an integral structure with continuous distribution in different regions of itself. This can provide another example of the morphology of the island-shaped passivation structure 14, improve the applicability of the back-contact battery provided in the embodiments of the present application in different application scenarios, and reduce the process difficulty of manufacturing the back-contact battery. In this case, the island-shaped passivation structure 14 may have a relatively flat surface (at this time, the morphology of the island-shaped passivation structure 14 can refer to the morphology of the dot-shaped passivation parts with regular shapes described above); alternatively, the surface of the island-shaped passivation structure 14 may also have a fluctuating morphology, and the direction, position, and size of the protrusion or depression of the fluctuating morphology can be set according to actual needs and are not specifically limited here. The application principle of the beneficial effects when at least one island-shaped passivation structure 14 has continuous distribution in different regions and the surface of the island-shaped passivation structure 14 has a fluctuating morphology can refer to the application principle of the beneficial effects of the island-shaped passivation structure 14 including a plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner described above. It should be noted that Figure 20 the black elliptical contour line in

[0132] In addition, the edges of at least one island-shaped passivation structure can be approximately regular in shape. For example, when the island-shaped passivation structure is semi-spherical, the edge of the island-shaped passivation structure is circular. Another example is that when the island-shaped passivation structure is a pyramid-like shape, the edge of the island-shaped passivation structure is a polygon-like shape. Or, as Figures 2 to 4 shown, the edges of at least one island-shaped passivation structure 14 are irregular in shape, which is beneficial for the island-shaped passivation structure 14 to have side surfaces arranged in different directions, so that light incident from different directions can be reflected or refracted, which is beneficial for more incident light to be refracted into the battery, further improving the absorption ratio of incident light and the bifaciality of the back-contact battery. In this case, the specific morphology of the irregular-shaped edges of the island-shaped passivation structure 14 can be determined according to the three-dimensional morphology of the island-shaped passivation structure 14 described above, and no specific limitation is made here.

[0133] It should be noted that when the island-shaped passivation structure includes a plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner, the edge of the island-shaped passivation structure refers to the edge of the area occupied by the plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner as a whole. When different regions of the island-shaped passivation structure are continuously distributed, the edge of the island-shaped passivation structure refers to the edge surrounded by the continuously distributed different regions.

[0134] In terms of size, the embodiments of the present application do not specifically limit the size of the island-shaped passivation structure, which can be determined according to the passivation effect requirements for the island-shaped passivation structure in the actual application scenario and the light trapping requirements for the island-shaped passivation structure.

[0135] Exemplarily, the area occupied by at least one island-shaped passivation structure can be greater than or equal to 1 μm 2 and less than or equal to 100 μm 2 . For example, the area occupied by at least one island-shaped passivation structure can be greater than or equal to 1 μm 2 , 10 μm 2 , 20 μm 2 , 30 μm 2 , 50 μm 2 , 80 μm 2 or 100 μm 2 etc. When the area occupied by at least one island-shaped passivation structure is within the above range, it is beneficial to prevent the passivation effect of the island-shaped passivation structure from being too low due to the too small area occupied by the island-shaped passivation structure, as well as the degree of the light trapping effect of the island-shaped passivation structure itself or improved due to the setting of the island-shaped passivation structure, which is beneficial for the back-contact battery to have a high bifaciality. In addition, it can also prevent the area occupied by the island-shaped passivation structure from being too large (the beneficial effects of preventing the area occupied by the island-shaped passivation structure from being too large can be referred to the above, and will not be elaborated here).

[0136] Exemplarily, the area of ​​at least one island-shaped passivation structure in the platform area accounts for more than 50%. For example, the area of ​​at least one island-shaped passivation structure in the platform area may account for 51%, 55%, 60%, 70%, 75%, 80%, 85% or 90%, etc. This is beneficial for the island-shaped passivation structure to have a larger area in the platform area, which is beneficial for enhancing the adjustment effect of the island-shaped passivation structure on the light transmission path, which is beneficial for more incident light to be refracted into the battery, increasing the incident light absorption ratio, and further improving the bifaciality of the back contact battery.

[0137] Exemplarily, the longest side dimension of at least one island-shaped passivation structure may be greater than or equal to 0.5 μm and less than or equal to 9 μm. For example, the longest side dimension of at least one island-shaped passivation structure may be 0.5 μm, 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 8 μm or 9 μm.

[0138] Exemplarily, the shortest side dimension of at least one island-shaped passivation structure may be less than or equal to 0.05 μm and less than or equal to 7.5 μm. For example, the shortest side dimension of at least one island-shaped passivation structure may be 0.05 μm, 0.1 μm, 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 6.5 μm, 7 μm or 7.5 μm, etc.

[0139] It should be noted that when the island-shaped passivation structure includes a plurality of point-shaped passivation parts that are not adjacent to each other and are distributed in a clustered manner, the area occupied by the island-shaped passivation structure refers to the area occupied by the plurality of point-shaped passivation parts that are not adjacent to each other and are distributed in a clustered manner as a whole. When different regions of the island-shaped passivation structure are distributed continuously, the area occupied by the island-shaped passivation structure refers to the area enclosed by the different regions that are distributed continuously.

[0140] From the structural aspect, the island passivation structure can be a single-layer structure or a stacked structure composed of different layers. The material of the island passivation structure can be any material with passivation effect as long as it can be applied to the back contact battery provided in the embodiment of the present application.

[0141] Exemplarily, at least one island-shaped passivation structure includes a doped semiconductor passivation portion; and / or, at least one island-shaped passivation structure includes an interface passivation portion; and / or, at least one island-shaped passivation structure includes a doped semiconductor portion, and a doped silicon glass portion arranged on a side of the doped semiconductor portion facing away from the semiconductor substrate.

[0142] The island-shaped passivation structure can be formed by at least three passivation parts, namely a doped semiconductor passivation part, an interface passivation part, and a doped silicon glass passivation part, which have good effects and are compatible with the battery manufacturing process. While making the island-shaped passivation structure have a good passivation effect, it can also improve the yield of the back-contact battery. In addition, the doped semiconductor passivation part, the interface passivation part, and the doped silicon glass passivation part are also materials for manufacturing the back-contact battery. At this time, the manufacturing of the island-shaped passivation structure can be achieved while manufacturing the corresponding structures in the back-contact battery, improving the manufacturing efficiency of the back-contact battery and simplifying the manufacturing process of the back-contact battery.

[0143] It should be noted that the island-shaped passivation structure can only include the doped semiconductor passivation part, or only include the interface passivation part, or the island-shaped passivation structure can include only the interface passivation part and the doped semiconductor passivation part (in this case, the doped semiconductor passivation part can be arranged on the side of the interface passivation part away from the semiconductor substrate), or the island-shaped passivation structure can only include the doped semiconductor passivation part and the doped silicon glass passivation part, or the island-shaped passivation structure can include the interface passivation part, the doped semiconductor passivation part, and the doped silicon glass passivation part at the same time (in this case, the interface passivation part, the doped semiconductor passivation part, and the doped silicon glass passivation part can be stacked in sequence along the direction away from the semiconductor substrate).

[0144] The materials, thicknesses of the doped semiconductor passivation part, the interface passivation part, and the doped silicon glass passivation part included in the island-shaped passivation structure, as well as the conduction types of the doped semiconductor passivation part and the doped silicon glass passivation part can be determined according to actual needs and are not specifically limited here.

[0145] Exemplarily, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material and conduction type of the doped semiconductor part are the same as the material and conduction type of the second doped semiconductor layer respectively; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material and conduction type of the doped semiconductor part are the same as the material and conduction type of the first doped semiconductor layer respectively.

[0146] When in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material and conduction type of the doped semiconductor part are the same as the material and conduction type of the second doped semiconductor layer respectively, the manufacturing of at least one island-shaped passivation structure disposed between the first boundary and the first sidewall can be achieved while manufacturing the second doped semiconductor layer, improving the manufacturing efficiency of the back-contact battery and simplifying the manufacturing process of the back-contact battery. The application principle of the beneficial effects that in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material and conduction type of the doped semiconductor part are the same as the material and conduction type of the first doped semiconductor layer respectively can refer to the previous text and will not be elaborated here.

[0147] Exemplarily, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the thickness of the doped semiconductor portion may be less than or equal to the thickness of the second doped semiconductor layer; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the thickness of the doped semiconductor portion may be less than or equal to the thickness of the first doped semiconductor layer.

[0148] Of course, the material and / or conduction type of the doped semiconductor passivation portion included in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall may also be different from the material and / or conduction type of the second doped semiconductor layer, respectively. At this time, the doped semiconductor passivation portion included in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, and the second doped semiconductor layer may be manufactured separately. The material and / or conduction type of the doped semiconductor passivation portion included in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall may also be different from the material and / or conduction type of the first doped semiconductor layer, respectively.

[0149] Regarding the interface passivation portion included in at least one island-shaped passivation structure, as described above, in the case where the back contact battery further includes a first interface passivation layer, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material of the interface passivation portion is the same as the material of the second interface passivation layer; which is beneficial to improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process of the back contact battery.

[0150] Exemplarily, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the thickness of the interface passivation portion is less than or equal to the thickness of the second interface passivation layer.

[0151] Exemplarily, in the case where the back contact battery further includes a second interface passivation layer, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material of the interface passivation portion is the same as the material of the first interface passivation layer. Which is beneficial to improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process of the back contact battery.

[0152] Exemplarily, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the thickness of the interface passivation portion is less than or equal to the thickness of the first interface passivation layer.

[0153] Of course, the material of the interface passivation portion of at least one island-shaped passivation structure disposed between the first boundary and the first sidewall may also be different from the material of the second interface passivation layer. At this time, the interface passivation portion of at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, and the second interface passivation layer may be manufactured separately. The material of the interface passivation portion of at least one island-shaped passivation structure disposed between the second boundary and the second sidewall may also be different from the material of the second interface passivation layer.

[0154] When the back contact cell does not include the first interface passivation layer and / or the second interface passivation layer, the material of the interface passivation portion included in the corresponding island passivation structure may include any interface passivation layer material such as silicon oxide, aluminum oxide and intrinsic silicon.

[0155] As for the doped silicon glass portion included in at least one island-shaped passivation structure, for example, Figure 16 As shown, the back contact cell may also include a first doped silicon glass layer 30 disposed on the side of the first doped semiconductor layer 12 away from the semiconductor substrate 11. The first doped silicon glass layer 30 has the same conductivity type as the first doped semiconductor layer 12. The first doped semiconductor layer 12 is passivated on the side away from the semiconductor substrate 11, and is used to prevent the first doped semiconductor layer 12 from being affected when the second doped semiconductor layer 13 is manufactured, which is beneficial for the first doped semiconductor layer 12 to have a higher carrier shunting and collection ability. The embodiment of the present application does not specifically limit the doping concentration and thickness of the impurities in the first doped silicon glass layer 30. In this case, in at least one island-shaped passivation structure 14 disposed between the second boundary 22 and the second sidewall 20, the material and conductivity type of the doped silicon glass part can be the same as the material and conductivity type of the first doped silicon glass layer 30, respectively. To improve the manufacturing efficiency of the back contact cell and simplify the manufacturing process of the back contact cell.

[0156] Exemplarily, in the at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the thickness of the doped silicon glass portion may be less than or equal to the thickness of the first doped silicon glass layer.

[0157] For example, Figure 16 As shown, the back contact cell may also include a second doped silicon glass layer 31 disposed on the side of the second doped semiconductor layer 13 away from the semiconductor substrate 11. The second doped silicon glass layer 31 has the same conductivity type as the second doped semiconductor layer 13. Passivating the side of the second doped semiconductor layer 13 away from the semiconductor substrate 11 is beneficial for the second doped semiconductor layer 13 to have a higher carrier shunting and collection capability. The embodiment of the present application does not specifically limit the doping concentration and thickness of the impurities in the second doped silicon glass layer 31. In this case, in at least one island-shaped passivation structure 14 disposed between the first boundary 21 and the first sidewall 19, the material and conductivity type of the doped silicon glass portion may be respectively the same as the material and conductivity type of the second doped silicon glass layer 31. This improves the manufacturing efficiency of the back contact cell and simplifies the manufacturing process of the back contact cell.

[0158] Exemplarily, in the at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the thickness of the doped silicon glass portion may be less than or equal to the thickness of the second doped silicon glass layer.

[0159] Of course, the material and / or conductivity type of the doped silicon glass portion of at least one island-shaped passivation structure disposed between the first boundary and the first sidewall may also be different from the material and / or conductivity type of the second doped silicon glass layer, respectively. In this case, the doped silicon glass portion of at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, and the second doped silicon glass layer may be manufactured separately. The material and / or conductivity type of the doped silicon glass portion of at least one island-shaped passivation structure disposed between the second boundary and the second sidewall may also be different from the material and / or conductivity type of the first doped silicon glass layer.

[0160] In terms of the formation position, the island-shaped passivation structures included in the back contact battery may be at least partially disposed only between the first boundary and the first sidewall, may be disposed only between the second boundary and the second sidewall, or may be disposed between the first boundary and the first sidewall and between the second boundary and the second sidewall at the same time. The embodiments of the present application do not specifically limit the formation position of the island-shaped passivation structure, which can be determined according to the actual application scenario and the actual manufacturing process.

[0161] In some examples, as Figures 17 to 20 shown, at least one island-shaped passivation structure 14 included in the back contact battery is disposed on the side of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 facing away from the semiconductor substrate 11, and / or the island-shaped passivation structure 14 is disposed between the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 and the semiconductor substrate 11. To passivate the surface of the region where the island-shaped passivation structure 14 is formed, reduce the number of defects on the region surface, and reduce the carrier recombination rate; on the other hand, it can change the transmission path of the incident light (such as increasing the reflection path of the incident light), which is beneficial to more incident light refracting into the battery, improving the incident light absorption ratio, and improving the bifaciality of the back contact battery. It should be noted that Figure 19 the black elliptical contour line in

[0162] is a line drawn to show the approximate position of the island-shaped passivation structure 14 and does not belong to a part of the battery structure. Figure 17 and Figure 21 shown, when the island-shaped passivation structure 14 is disposed on the side of the first doped semiconductor layer 12 facing away from the semiconductor substrate 11, the island-shaped passivation structure 14 does not belong to a part of the first doped semiconductor layer 12, and it is an additional passivation structure disposed on the side of the first doped semiconductor layer 12 facing away from the semiconductor substrate 11 and having an island shape. As Figure 18 and Figure 22 shown, when the island-shaped passivation structure 14 is disposed on the side of the second doped semiconductor layer 13 facing away from the semiconductor substrate 11, the island-shaped passivation structure 14 does not belong to a part of the second doped semiconductor layer 13 and is a passivation structure disposed outside the second doped semiconductor layer. As Figure 18As shown, when the island-shaped passivation structure 14 is disposed between the first doped semiconductor layer 12 and the semiconductor substrate 11, the island-shaped passivation structure 14 neither belongs to the first doped semiconductor layer 12 nor the semiconductor substrate 11, and is a passivation structure additionally disposed outside the second doped semiconductor layer. As Figure 17 and Figure 18 shown, when the island-shaped passivation structure 14 is disposed between the second doped semiconductor layer 13 and the semiconductor substrate 11, the island-shaped passivation structure 14 neither belongs to the second doped semiconductor layer 13 nor the semiconductor substrate 11, and is a passivation structure additionally disposed outside the second doped semiconductor layer.

[0163] The information such as the morphology, size, area, structure, and material of the island-shaped passivation structure disposed on the side of the first doped semiconductor layer and / or the second doped semiconductor layer facing away from the semiconductor substrate, and / or disposed between the first doped semiconductor layer and / or the second doped semiconductor layer and the semiconductor substrate can refer to the information such as the morphology, size, area, structure, and material of the island-shaped passivation structure disposed between the first boundary and the first sidewall, and / or disposed between the second boundary and the second sidewall, which will not be elaborated here.

[0164] In terms of distribution, the island-shaped passivation structures disposed in the first region and the second region in the back contact battery can be randomly distributed. Optionally, as Figure 19 and Figure 20 shown, among the island-shaped passivation structures disposed in the first region and the second region, at least some of the island-shaped passivation structures 14 can be regularly distributed. In this case, the distribution rule can be set according to the interaction characteristics between the incident light and the island-shaped passivation structure 14 to regularly reflect or refract the incident light on the first surface side of the back contact battery, and be combined with the self-irregular light trapping of the island-shaped passivation structure to maximize the utilization of the incident light, and is also beneficial to further improving the self-light trapping effect of the island-shaped passivation structure 14. Or because the island-shaped passivation structure 14 is disposed between the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 and the semiconductor substrate 11, the side of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 facing away from the semiconductor substrate 11 has a high light trapping effect, reducing the light shielding effect, and further increasing the incident light absorption ratio and the bifaciality of the back contact battery.

[0165] In the actual application process, in the back contact battery, which island-shaped passivation structures are regularly distributed can be determined according to the light trapping requirements of different regions on the back side of the battery, and no specific limitation is made here. As Figure 19 and Figure 20As shown, different island-shaped passivation structures 14 provided on one side of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 facing away from the semiconductor substrate 11 may be regularly distributed; alternatively, different island-shaped passivation structures 14 provided between the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 and the semiconductor substrate 11 may be regularly distributed; or all the island-shaped passivation structures 14 included in the back contact battery may be regularly distributed.

[0166] At least some of the island-shaped passivation structures being regularly distributed means that different island-shaped passivation structures among these island-shaped passivation structures are distributed in a regular pattern. For example: different island-shaped passivation structures are distributed along a fixed direction (such as being distributed in a matrix or concentric circle pattern, etc.). Another example: different island-shaped passivation structures are distributed at approximately the same spacing. Still another example: different island-shaped passivation structures are distributed in approximately the same pattern morphology.

[0167] In terms of the formation position, the island-shaped passivation structures included in the back contact battery may be provided only on one side of the first doped semiconductor layer facing away from the semiconductor substrate, may be provided only on one side of the second doped semiconductor layer facing away from the semiconductor substrate, may be provided only between the first doped semiconductor layer and the semiconductor substrate, may be provided only between the second doped semiconductor layer and the semiconductor substrate, or may be a combination of at least two of the above four cases. The embodiments of the present application do not specifically limit the formation position of the island-shaped passivation structures, which can be determined according to the actual application scenario and the actual manufacturing process.

[0168] Exemplarily, as Figure 17 shown, the island-shaped passivation structures 14 provided on the first region 15 may be located on one side of the first doped semiconductor layer 12 facing away from the semiconductor substrate 11, and the island-shaped passivation structures 14 provided on the second region 16 may be provided between the second doped semiconductor layer 13 and the semiconductor substrate 11.

[0169] Or, as Figure 22 shown, the island-shaped passivation structures 14 provided on the first region 15 are located between the first doped semiconductor layer 12 and the semiconductor substrate 11, and the island-shaped passivation structures 14 provided on the second region 16 are provided on one side of the second doped semiconductor layer 13 facing away from the semiconductor substrate 11.

[0170] It is worth noting that the first doped semiconductor layer and the second doped semiconductor layer included in the back contact battery are respectively formed on the local area of ​​the first surface in different operation steps. In addition, in the process of manufacturing the first doped semiconductor layer and the second doped semiconductor layer, the patterned first doped semiconductor layer and the second doped semiconductor layer are obtained by selectively etching the doped semiconductor layer set in the entire layer. Therefore, the island-shaped passivation structure arranged on the first area is located on the side of the first doped semiconductor layer away from the semiconductor substrate, and the island-shaped passivation structure arranged on the second area is arranged between the second doped semiconductor layer and the semiconductor substrate. For example, the first doped semiconductor layer can be manufactured first, and the island-shaped passivation structure arranged between the second doped semiconductor layer and the semiconductor substrate can be manufactured based on the part of the doped semiconductor material of the first doped semiconductor layer located in the second area. At the same time, after forming the first doped semiconductor layer and the island-shaped passivation structure arranged on the second area, the second doped semiconductor layer is manufactured, and the island-shaped passivation structure arranged on the side of the first doped semiconductor layer away from the semiconductor substrate can be manufactured based on the part of the doped semiconductor material of the second doped semiconductor layer located in the first area, which is conducive to improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process of the back contact battery.

[0171] In a second aspect, an embodiment of the present application provides a photovoltaic module, the photovoltaic module comprising: a battery string and an encapsulation layer. The battery string is formed by electrically connecting a plurality of back-contact batteries provided by the first aspect and various implementations thereof; and the encapsulation layer covers the surface of the battery string.

[0172] The beneficial effects of the second aspect and its various implementations in the embodiments of the present application can be analyzed by referring to the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0173] Unless there are technical obstacles or contradictions, the various technical features disclosed in this application can be freely combined to form additional embodiments, and these additional embodiments are all within the protection scope of this application.

[0174] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0175] The embodiments of the present application have been described above. However, these embodiments are merely for the purpose of illustration with greater clarity and not for limiting the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents. Without departing from the scope of the present application, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present application.

Claims

1. A back contact battery, characterized in that: include: A semiconductor substrate, a first doped semiconductor layer, a second doped semiconductor layer and an island passivation structure; The semiconductor substrate has a first surface and a second surface opposite to each other; The first surface includes first areas and second areas that are alternately spaced and a spacing area between the first areas and the second areas; Along the direction from the first surface to the second surface, the surface of the spacing region is concave toward the semiconductor substrate relative to the surface of the first region to form a groove structure; the groove structure has a first sidewall close to the first region and a second sidewall close to the second region; The first doped semiconductor layer is disposed on the first region, and the first doped semiconductor layer has a first boundary close to the spacing region; The second doped semiconductor layer is disposed on the second region, the second doped semiconductor layer and the first doped semiconductor layer have opposite conductivity types, and the second doped semiconductor layer has a second boundary close to the spacing region; The island-shaped passivation structure is disposed on the semiconductor substrate; wherein at least one of the island-shaped passivation structures is at least partially located between the first boundary and the first sidewall; And / or, at least one of the island-shaped passivation structures is at least partially located between the second boundary and the second sidewall.

2. The back contact cell according to claim 1, characterized in that: The first boundary has a first sub-boundary located in the first region and spaced apart from the first sidewall along the width direction of the spacing region, and the island passivation structure is disposed between at least one of the first sub-boundary and the first sidewall; And / or, the second boundary has a second sub-boundary located in the second region and spaced apart from the second sidewall along the width direction of the spacing region, and the island passivation structure is arranged between at least one of the second sub-boundary and the second sidewall.

3. The back contact battery according to claim 1, characterized in that: A portion of the first region close to the first sidewall and not directly covered by the first doped semiconductor layer is a platform region, and / or a portion of the second region close to the second sidewall and not directly covered by the second doped semiconductor layer is a platform region; The platform region includes a plane substantially parallel to the first surface; at least one island-shaped passivation structure is disposed on the plane included in the platform region.

4. The back contact cell according to claim 3, characterized in that: Along the width direction of the spacing region, the width of the plane included in at least one of the terrace regions is less than or equal to 1 μm.

5. The back contact battery according to claim 3, characterized in that: In the case where the first region has the platform area, at least one of the platform areas further includes a third sidewall that is away from the first sidewall and continuous with the plane; and / or, in the case where the second region has the platform area, at least one of the platform areas further includes a third sidewall that is away from the second sidewall and continuous with the plane; Wherein, the third side wall is vertically arranged relative to the plane, or the third side wall is inclined relative to the plane.

6. The back contact cell according to claim 5, characterized in that: At least one of the island-shaped passivation structures further extends from the plane to at least a portion of the third sidewall; And / or, along the thickness direction of the semiconductor substrate, the height of the third sidewall is greater than or equal to 0.05 μm and less than or equal to 8 μm.

7. The back contact battery according to claim 5, characterized in that: In the case where the first region has the platform area, part of the first boundary also extends above the plane included in the platform area, and the first doped semiconductor layer and the island-shaped passivation structure are distributed at intervals; And / or, in the case where the second region has the platform area, part of the second boundary also extends above the plane included in the platform area, and the second doped semiconductor layer and the island-shaped passivation structure are distributed at intervals.

8. The back contact battery according to claim 7, characterized in that: In the case where part of the first boundary also extends above the plane included in the platform area, along the thickness direction of the semiconductor substrate, a distance between the first doped semiconductor layer and the island-shaped passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm; And / or, in the case where part of the second boundary also extends above the plane included in the platform area, along the thickness direction of the semiconductor substrate, the distance between the second doped semiconductor layer and the island-shaped passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm.

9. The back contact cell according to claim 7, characterized in that: In the case where part of the first boundary also extends above the plane included in the platform area, along the width direction of the spacing area, the extension width of the first boundary relative to the third sidewall is less than or equal to 1 μm; And / or, in the case where part of the second boundary further extends above the plane included in the platform area, along the width direction of the spacing area, the extension width of the second boundary relative to the third sidewall is less than or equal to 1 μm.

10. The back contact battery according to claim 3, characterized in that: The area of ​​at least one of the island-shaped passivation structures in the platform region accounts for more than 50%.

11. The back contact cell according to claim 2, characterized in that: The first boundary is in a first concave-convex alternating structure, and the boundary of at least part of the concave parts in the first concave-convex alternating structure is the first sub-boundary; And / or, the second boundary is in a second concave-convex alternating structure, and boundaries of at least part of the concave portions in the second concave-convex alternating structure are the second sub-boundaries.

12. The back contact cell according to claim 11, characterized in that: At least part of the convex portions in the first concave-convex alternating structure and / or the second concave-convex alternating structure extends to above the concave groove structure along the width direction of the spacing area.

13. The back contact cell according to claim 12, characterized in that: The extension width of at least one of the convex portions in the first concave-convex alternating structure relative to the first side wall above the groove structure is less than or equal to 1 μm; And / or, an extension width of at least one of the convex portions in the second concave-convex alternating structure relative to the second side wall above the groove structure is less than or equal to 1 μm.

14. The back contact cell according to claim 11, characterized in that: Along the extension direction of the spacing area, the first side wall presents a third concave-convex alternating structure, and at least part of the convex portions in the third concave-convex alternating structure are staggered with adjacent convex portions in the first concave-convex alternating structure; And / or, along the extension direction of the spacing area, the second side wall presents a fourth concave-convex alternating structure, and at least part of the convex portions in the fourth concave-convex alternating structure are staggered with adjacent convex portions in the second concave-convex alternating structure.

15. The back contact cell according to claim 1, characterized in that: At least one of the island-shaped passivation structures comprises a doped semiconductor passivation portion; and / or, at least one of the island-shaped passivation structures comprises an interface passivation portion; And / or, at least one of the island-shaped passivation structures includes a doped semiconductor portion and a doped silicon glass portion disposed on a side of the doped semiconductor portion facing away from the semiconductor substrate.

16. The back contact cell according to claim 15, characterized in that In at least one of the island-shaped passivation structures disposed between the first boundary and the first sidewall, the material and conductivity type of the doped semiconductor portion are respectively the same as the material and conductivity type of the second doped semiconductor layer; And / or, in at least one of the island-shaped passivation structures disposed between the second boundary and the second sidewall, the material and the conductivity type of the doped semiconductor portion are respectively the same as the material and the conductivity type of the first doped semiconductor layer.

17. The back contact cell according to claim 15, characterized in that: The back contact cell further comprises a first interface passivation layer disposed between the semiconductor substrate and the first doped semiconductor layer, and a second interface passivation layer disposed between the semiconductor substrate and the second doped semiconductor layer; Wherein, in at least one of the island-shaped passivation structures disposed between the first boundary and the first sidewall, the material of the interface passivation portion is the same as the material of the second interface passivation layer; And / or, in at least one of the island-shaped passivation structures disposed between the second boundary and the second sidewall, a material of the interface passivation portion is the same as a material of the first interface passivation layer.

18. The back contact cell according to claim 15, characterized in that The back contact cell further comprises a first doped silicon glass layer disposed on a side of the first doped semiconductor layer away from the semiconductor substrate, and a second doped silicon glass layer disposed on a side of the second doped semiconductor layer away from the semiconductor substrate; The first doped silicon glass layer has the same conductivity type as the first doped semiconductor layer; the second doped silicon glass layer has the same conductivity type as the second doped semiconductor layer; Wherein, in at least one of the island-shaped passivation structures disposed between the first boundary and the first sidewall, the material and the conductivity type of the doped silicon glass portion are respectively the same as the material and the conductivity type of the second doped silicon glass layer; And / or, in at least one of the island-shaped passivation structures disposed between the second boundary and the second sidewall, the material and the conductivity type of the doped silicon glass portion are respectively the same as the material and the conductivity type of the first doped silicon glass layer.

19. A photovoltaic module, characterized in that: The photovoltaic module comprises: a battery string, the battery string being formed by electrically connecting a plurality of back-contact batteries according to any one of claims 1 to 18; and an encapsulation layer, wherein the encapsulation layer covers the surface of the battery string.

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