HBC battery, battery pack and photovoltaic system

Abstract

The utility model is applicable to the field of photovoltaic technology, and provides an HBC battery, a battery pack and a photovoltaic system, the HBC battery comprises a silicon substrate, the silicon substrate is provided with a backlight surface and a light facing surface which are oppositely arranged, the backlight surface of the silicon substrate is provided with a first area and a second area, the first area and the second area are alternately arranged, and the first area and the second area are not overlapped; an amorphous silicon layer is arranged in the first region, a polycrystalline silicon layer is arranged in the second region, the amorphous silicon layer and the polycrystalline silicon layer are shaped, and the refractive index of the amorphous silicon layer is larger than that of the polycrystalline silicon layer. And the parasitic absorption of light of the amorphous silicon layer is reduced, the optical utilization rate is improved, the unnecessary energy loss is reduced, and finally, the photoelectric conversion efficiency and the performance of the HBC battery are comprehensively improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to photovoltaic technical field especially relates to a kind of HBC battery, battery pack and photovoltaic system. BACKGROUND

[0002] In the existing HBC (heterojunction with back contact) battery, compared with BC (back contact) battery, significant progress has been made, but there are still some technical problems, which limit its further improvement of photoelectric conversion efficiency and reduce manufacturing cost.

[0003] HBC battery relies on heterojunction structure in design, which improves photoelectric conversion efficiency, and improper heterojunction processing can easily lead to the recombination of generated carriers before reaching the electrode, reducing the current that can be collected, resulting in increased recombination rate of carriers. And the lack of material density leads to poor etching resistance, especially during electrode manufacturing process, the electrode slurry used may cause damage or penetration to the material layer, affecting the matching between electrode and silicon layer, and further affecting the overall performance and stability of the battery. SUMMARY

[0004] The utility model provides a kind of HBC battery, to solve the problem of the recombination rate of carrier increase and the stability of insufficient in the existing HBC battery.

[0005] The utility model is realized as follows: a kind of HBC battery, comprising:

[0006] Silicon substrate, the silicon substrate has oppositely arranged back light surface and light surface, first area and second area are arranged on the back light surface of the silicon substrate, the first area and the second area are alternately arranged, the first area and the second area do not overlap;

[0007] Amorphous silicon layer is included in the first area, and polycrystalline silicon layer is included in the second area, the amorphous silicon layer and the polycrystalline silicon layer are different types, and the refractive index of the amorphous silicon layer is greater than the refractive index of the polycrystalline silicon layer.

[0008] Optionally, the ratio of the refractive index of the amorphous silicon layer to the refractive index of the polycrystalline silicon layer is greater than 1 and less than 1.2.

[0009] Optionally, the difference between the refractive index of the amorphous silicon layer and the refractive index of the polycrystalline silicon layer is greater than 0.01 and less than 0.5.

[0010] Optionally, it further includes isolation region, and the isolation region is placed between the first area and the second area.

[0011] Optionally, the thickness of the amorphous silicon layer is greater than 13nm and less than 17nm.

[0012] Optionally, the thickness of the polysilicon layer is greater than 280nm and less than 300nm.

[0013] Optionally, the extinction coefficient of the amorphous silicon layer is greater than the extinction coefficient of the polysilicon layer.

[0014] Optionally, the ratio of the extinction coefficient of the amorphous silicon layer to the extinction coefficient of the polysilicon layer is greater than 1.3 and less than 11.

[0015] Optionally, the difference between the extinction coefficient of the amorphous silicon layer and the extinction coefficient of the polysilicon layer is greater than 0.01 and less than 0.08.

[0016] Optionally, the amorphous silicon layer is a P-type amorphous silicon layer and the polysilicon layer is an N-type polysilicon layer.

[0017] The utility model also provides a battery pack comprising the HBC battery.

[0018] The utility model also provides a photovoltaic system comprising the battery pack.

[0019] The utility model reaches the beneficial effect that because the first area and the second area that do not overlap are arranged alternately on the back light surface of the silicon base, the refractive index of the amorphous silicon layer arranged in the first area is greater than the refractive index of the polysilicon layer arranged in the second area, the parasitic absorption of amorphous silicon layer light is reduced, the optical utilization rate is improved, unnecessary energy loss is reduced, and the photoelectric conversion efficiency and performance of the HBC battery are improved ultimately. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is the schematic diagram of solar cell structure provided by the utility model.

[0021] Mark explanation:

[0022] 100, HBC battery;110, first area;111, amorphous silicon layer;120, second area;121, polysilicon layer;130, isolation area;140, silicon base. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the utility model more clearly, the following will be further described in detail by combining with the drawings and examples. The examples of the examples are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The examples described below by referring to the drawings are exemplary and are only used to explain the utility model, and cannot be understood as limiting the utility model. In addition, it should be understood that the specific examples described herein are only used to explain the utility model, and are not used to limit the utility model.

[0024] In the description of the utility model, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as limiting the utility model.

[0025] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "multiple" is two or more than two, unless otherwise specifically limited.

[0026] In the description of the utility model, it should be noted that unless otherwise specifically specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the communication or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0027] In the utility model, unless another definite provision and limitation, first feature is "on" or "under" second feature, can include that first and second features are in direct contact, also can include that first and second features are not in direct contact but contact through other feature between them.Moreover, first feature "on", "above" and "on" second feature includes that first feature is directly above and obliquely above second feature, or only indicates that first feature horizontal height is higher than second feature.First feature "under", "below" and "under" second feature includes that first feature is directly below and obliquely below second feature, or only indicates that first feature horizontal height is less than second feature.

[0028] The disclosure below provides many different embodiments or examples for implementing different structures of the utility model. In order to simplify the disclosure of the utility model, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the utility model. In addition, the utility model can refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the utility model provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0029] The utility model in silicon substrate's back light surface alternately sets first area and second area not overlapping, the refractive index of amorphous silicon layer in first area is greater than the refractive index of polycrystalline silicon layer in second area, reduce the parasitic absorption of amorphous silicon layer light, improve optical utilization, reduce unnecessary energy loss, finally comprehensive come up HBC battery's photoelectric conversion efficiency and performance.

[0030] Example One

[0031] As Figure 1 The utility model provides a kind of HBC battery 100, comprising:

[0032] Silicon substrate 140, silicon substrate 140 has oppositely arranged back light surface and light surface, first area 110 and second area 120 are arranged on the back light surface of silicon substrate 140, first area 110 and second area 120 are alternately arranged, and first area 110 and second area 120 do not overlap.

[0033] Amorphous silicon layer 111 is included in first area 110, and polycrystalline silicon layer 121 is included in second area 120, and amorphous silicon layer 111 and polycrystalline silicon layer 121 are different types, and the refractive index of amorphous silicon layer 111 is greater than the refractive index of polycrystalline silicon layer 121.

[0034] The HBC cell 100 (Heterojunction with Back Contact solar cell) is a solar cell with a heterojunction structure and a back contact design. It combines the advantages of different materials to improve photoelectric conversion efficiency. The heterojunction, formed on the back of the cell by different types of silicon materials (typically amorphous silicon and polycrystalline silicon), enhances cell performance.

[0035] The silicon substrate 140 has two main surfaces, a light-facing surface and a backlight surface. The light-facing surface directly faces the sunlight, while the backlight surface is the other side. The two surfaces are arranged opposite each other.

[0036] Two distinct regions are arranged on the backlight surface of the silicon substrate 140: a first region 110 and a second region 120. The two regions are arranged alternately and do not overlap. The first region 110 and the second region 120 can be arranged adjacent to each other, or another region can be provided between the first region 110 and the second region 120.

[0037] The first region 110 includes an amorphous silicon layer 111. The atomic arrangement of this layer is disordered, lacking long-range order. The second region 120 includes a polycrystalline silicon layer 121. Polycrystalline silicon is composed of multiple small silicon crystals. These grains aggregate to form a larger structure, but with grain boundaries between them. The amorphous silicon layer 111 and the polycrystalline silicon layer 121 are of different types. That is, when the amorphous silicon layer 111 is P-type, the polycrystalline silicon layer 121 is N-type. When the amorphous silicon layer 111 is N-type, the polycrystalline silicon layer 121 is P-type. The N-type and P-type layers form a PN junction.

[0038] Parasitic absorption refers to the ineffective absorption of light in the cell structure. Specifically, it refers to the absorption of photons by other material layers before they reach the photoelectric conversion region (usually the light absorption layer), resulting in the ineffective conversion of the energy of these photons into electrical energy. In solar cells, parasitic absorption reduces the overall energy conversion efficiency. The amorphous silicon layer 111 with a high refractive index acts as a waveguide in the cell structure, guiding the incident light to reflect multiple times within the polysilicon layer 121 and the silicon substrate 140. Each reflection increases the propagation path of the photon, increasing the chance of effective absorption, further reducing the probability of parasitic absorption, and increasing the chance of light absorption, thereby increasing the probability of generating electron-hole pairs and improving light utilization.

[0039] Amorphous silicon and polycrystalline silicon form a heterojunction structure, and the interface characteristics of this structure determine the recombination rate of charge carriers. Amorphous silicon has a higher refractive index and good interface passivation properties, which reduces surface recombination losses, giving generated electrons and holes more opportunities to be collected and transferred to the battery electrodes.

[0040] In this embodiment, the first region 110 and the second region 120 are alternately arranged on the back surface of the silicon substrate 140 without overlapping, the refractive index of the amorphous silicon layer 111 in the first region 110 is greater than the refractive index of the polysilicon layer 121 in the second region 120, the parasitic absorption of light by the amorphous silicon layer 111 is reduced, the optical utilization rate is improved, unnecessary energy loss is reduced, and ultimately the photoelectric conversion efficiency and performance of the HBC cell 100 are improved.

[0041] Example Two

[0042] On the basis of Embodiment Seven, the ratio of the refractive index of the amorphous silicon layer 111 to the refractive index of the polysilicon layer 121 is greater than 1 and less than 1.2.

[0043] By precisely controlling the refractive index ratio of the amorphous silicon layer 111 and the polysilicon layer 121 to be between 1 and 1.2, the light propagation path can be precisely controlled to ensure effective transmission and absorption of light, maximizing optical utilization. This ratio range helps to achieve micro-optical matching between layers, reducing light reflection loss at the interface, thereby improving the light absorption efficiency of the cell.

[0044] Example Three

[0045] On the basis of Embodiment One, the difference between the refractive index of the amorphous silicon layer 111 and the refractive index of the polysilicon layer 121 is greater than 0.01 and less than 0.5.

[0046] Limiting the refractive index difference between the amorphous silicon layer 111 and the polysilicon layer 121 to between 0.01 and 0.5 minimizes light reflection between the two layers, thereby improving light absorption efficiency. This refractive index difference range helps to achieve multiple reflections and effective transmission of light within the cell, thereby increasing optical utilization.

[0047] Example Four

[0048] On the basis of Embodiment One, it further comprises an isolation region 130, which is disposed between the first region 110 and the second region 120.

[0049] The isolation region 130 can effectively separate the first region 110 and the second region 120, preventing mixing and recombination of charge carriers. In this way, charges can be more effectively separated and transmitted within their respective regions. The isolation region 130 reduces the opportunity for photo-generated carriers to migrate across regions, reducing the probability of carrier recombination, thereby improving the photoelectric conversion efficiency of the solar cell.

[0050] The isolation region 130 also helps to reduce interfacial defects between the amorphous silicon layer 111 and the poly-silicon layer 121. These defects are often the main source of carrier recombination, so by the provision of the isolation region 130, the passivation effect of the interface can be improved, thereby improving the performance of the cell. The presence of the isolation region 130 makes the interface between the amorphous silicon layer 111 and the poly-silicon layer 121 more stable, reducing the spread of defects caused by repeated stress and thermal cycling of the interface.

[0051] Example Five

[0052] On the basis of embodiment one, the thickness of the amorphous silicon layer 111 is greater than 13 nm and less than 17 nm.

[0053] The thickness of the amorphous silicon layer 111 in the range of 13 nm to 17 nm is conducive to more efficient charge separation. An amorphous silicon layer 111 that is too thick can increase the recombination rate of charges, while a layer that is too thin can not be sufficient to effectively separate photo-generated carriers. A reasonable thickness of the amorphous silicon layer 111 can provide a better charge transport path, reducing energy loss during charge transport, thereby improving the photoelectric conversion efficiency of the cell.

[0054] Example Six

[0055] On the basis of embodiment one, the thickness of the poly-silicon layer 121 is greater than 280 nm and less than 300 nm.

[0056] The thickness of the poly-silicon layer 121 in the range of 280 nm to 300 nm is conducive to efficient separation of photo-generated charges. This thickness range avoids the recombination of charges within the material, while providing sufficient volume to support efficient charge transport. A poly-silicon layer 121 with a thickness in this range can reduce resistance and increase the speed of carrier transport, thereby improving the fill factor and overall efficiency of the cell.

[0057] Example Seven

[0058] On the basis of embodiment one, the refractive index of the amorphous silicon layer 111 is greater than the refractive index of the poly-silicon layer 121.

[0059] The higher the extinction coefficient, the stronger the ability to absorb light, and the lower the extinction coefficient, the weaker the ability to absorb light. The extinction coefficient of the amorphous silicon layer 111 is greater than the extinction coefficient of the poly-silicon layer 121, so the ability of the amorphous silicon layer 111 to absorb light is greater than the ability of the poly-silicon layer 121 to absorb light.

[0060] At the same time, the smaller the extinction coefficient means that the material structure is more dense and uniform. The defects and voids inside the dense polysilicon layer 121 are fewer, which leads to the enhancement of its physical stability and mechanical strength. On the one hand, the polysilicon layer 121 has high density, and the structure is more stable and uniform, which can better resist the etching of the electrode slurry in the manufacturing process. This can ensure that the polysilicon layer 121 maintains its integrity during the electrode printing and sintering process, reducing the loss of electrical performance caused by etching. On the other hand, the high density of the polysilicon layer 121 can effectively passivate the surface, reduce the trap states on the surface and in the bulk, and thus reduce the recombination rate of electrons and holes on the back surface side.

[0061] Example Eight

[0062] On the basis of embodiment one, the ratio of the extinction coefficient of the amorphous silicon layer 111 to the extinction coefficient of the polysilicon layer 121 is greater than 1.3 and less than 11.

[0063] By selecting the amorphous silicon layer 111 and the polysilicon layer 121 with an extinction coefficient ratio between 1.3 and 11, efficient light absorption and optimized light management are achieved in the first region 110 and the second region 120. This is crucial for enhancing light capture and the generation of electron-hole pairs. The appropriate extinction coefficient ratio ensures good matching of the polysilicon layer 121 with the electrode slurry, reduces electrical contact resistance, enhances electrode adhesion, makes the polysilicon layer 121 have higher resistance to electrode slurry etching, and ensures the stability of the layer structure during printing and sintering. By precisely controlling the extinction coefficient ratio of the amorphous silicon layer 111 and the polysilicon layer 121, the surface is effectively passivated, the defects caused by disordered structures are reduced, and the carrier recombination rate is reduced. The field passivation effect is enhanced, which helps to improve the open-circuit voltage and fill factor of the battery, and ultimately improves the photoelectric conversion efficiency.

[0064] The extinction coefficient is reasonably selected to achieve the best balance between light absorption and electrical conductivity of the amorphous silicon layer 111 and the polysilicon layer 121. This improves the photoelectric conversion efficiency of the solar cell, prolongs the service life of the battery, and improves the output power and use stability.

[0065] Example Nine

[0066] On the basis of embodiment one, the difference between the extinction coefficient of the amorphous silicon layer 111 and the extinction coefficient of the polysilicon layer 121 is greater than 0.01 and less than 0.08.

[0067] Specifically, amorphous silicon has a higher extinction coefficient, more effectively absorbing high-energy photons, while the extinction coefficient of polycrystalline silicon is lower, but in this small difference range, it can more uniformly absorb photons, thereby improving the light absorption efficiency of the entire cell. Due to the difference between 0.01 and 0.08, the reflection and scattering effect of photons at the interface of the two materials is low, plus the appropriate anti-reflection layer design, which can further reduce light loss and optimize light capture.

[0068] Example Ten

[0069] On the basis of Embodiment One, the amorphous silicon layer 111 is a P-type amorphous silicon layer 111, and the polycrystalline silicon layer 121 is an N-type polycrystalline silicon layer 121.

[0070] Amorphous silicon has a higher defect state density, and these defects can capture electrons, resulting in lower electron mobility. However, holes move more smoothly in amorphous silicon, so amorphous silicon is more suitable as a P-type material. Amorphous silicon as a P-type material can also effectively passivate the interface with polycrystalline silicon or crystalline silicon substrate 140, reducing carrier recombination caused by interface defect states, thereby improving interface quality. And the long-term stability of amorphous silicon as a P-type layer is good, the process is mature, and the process parameters are relatively easy to control, meeting the requirements of large-scale industrial production.

[0071] N-type polycrystalline silicon has a large number of free electrons, high electron mobility, and can effectively improve the conductivity of the device and reduce resistance loss. The crystalline structure of polycrystalline silicon is better than that of amorphous silicon, with a lower defect state density, which makes polycrystalline silicon a better N-type material for conducting electrons.

[0072] Setting the amorphous silicon layer 111 as P-type and the polycrystalline silicon layer 121 as N-type makes full use of the advantages of each material, optimizes the transmission and separation efficiency of carriers, and improves the photoelectric conversion efficiency.

[0073] Example Eleven

[0074] The present embodiment provides a battery pack comprising the HBC cell 100 of the above-mentioned embodiments.

[0075] The battery pack of the present embodiment has the same beneficial effects as the HBC cell 100 described above, and will not be repeated here.

[0076] Example Twelve

[0077] The present embodiment provides a photovoltaic system comprising the battery pack of the above-mentioned embodiments.

[0078] The photovoltaic system of the present embodiment has the same beneficial effects as the battery pack described above, and will not be repeated here.

[0079] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An HBC battery, characterized in that: include: A silicon substrate having a backlight surface and a light-facing surface opposite to each other, wherein a first region and a second region are arranged on the backlight surface of the silicon substrate, the first region and the second region are arranged alternately, and the first region and the second region do not overlap; The first region includes an amorphous silicon layer, and the second region includes a polycrystalline silicon layer. The amorphous silicon layer and the polycrystalline silicon layer are of different types, and the refractive index of the amorphous silicon layer is greater than the refractive index of the polycrystalline silicon layer.

2. The HBC battery according to claim 1, wherein: The ratio of the refractive index of the amorphous silicon layer to the refractive index of the polysilicon layer is greater than 1 and less than 1.

2.

3. The HBC battery according to claim 1, wherein: The difference between the refractive index of the amorphous silicon layer and the refractive index of the polysilicon layer is greater than 0.01 and less than 0.

5.

4. The HBC battery according to claim 1, wherein: Also included is an isolation region disposed between the first region and the second region.

5. The HBC battery according to claim 1, wherein: The thickness of the amorphous silicon layer is greater than 13 nm and less than 17 nm.

6. The HBC battery according to claim 1, wherein: The thickness of the polysilicon layer is greater than 280 nm and less than 300 nm.

7. The HBC battery according to claim 1, wherein: The extinction coefficient of the amorphous silicon layer is greater than the extinction coefficient of the polysilicon layer.

8. The HBC battery according to claim 7, wherein: The ratio of the extinction coefficient of the amorphous silicon layer to the extinction coefficient of the polycrystalline silicon layer is greater than 1.3 and less than 11.

9. The HBC battery according to claim 1, wherein: The difference between the extinction coefficient of the amorphous silicon layer and the extinction coefficient of the polycrystalline silicon layer is greater than 0.01 and less than 0.

08.

10. The HBC battery according to claim 1, wherein: The amorphous silicon layer is a P-type amorphous silicon layer, and the polycrystalline silicon layer is an N-type polycrystalline silicon layer.

11. A battery pack, characterized in that: The HBC battery comprises the HBC battery according to any one of claims 1 to 10.

12. A photovoltaic system, characterized in that: A battery pack comprising the battery pack of claim 11.

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