Back contact solar cell, cell module and photovoltaic system

Abstract

The invention relates to the technical field of solar cells, and particularly discloses a back contact solar cell, a cell module and a photovoltaic system, and the cell comprises a silicon substrate which is provided with a light receiving surface and a backlight surface which are opposite to each other; a doping layer and an electrode layer are sequentially arranged on the backlight face in the direction away from the light receiving face, the doping layer comprises N-type doping layers and P-type doping layers which are alternately arranged at intervals, the electrode layer comprises N-type electrodes and P-type electrodes, the electrical conductivity of the silicon substrate, the electrical conductivity of the P-type doping layers and the electrical conductivity of the N-type doping layers are sequentially increased, and the electrical conductivity of the P-type doping layers and the electrical conductivity of the N-type doping layers are sequentially increased. When the silicon substrate is a P-type silicon substrate, the total length of all the N-type electrodes is greater than the total length of all the P-type electrodes; when the silicon substrate is an N-type silicon substrate, the total length of all the P-type electrodes is larger than the total length of all the N-type electrodes. Separation of photo-generated electron hole pairs and collection of current can be enhanced, series resistance can be effectively reduced, power loss in the cell is reduced, filling factors are improved, meanwhile, the effective power generation area of the silicon substrate is increased, more photo-generated carriers are generated, short-circuit current is improved, and the conversion efficiency of the cell is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a back-contact solar cell, a cell assembly and a photovoltaic system. Background Art

[0002] In current conventional solar cells, the front electrode and the back electrode are respectively arranged on the light-receiving side and the light-proof side of the substrate. The current transmission of carriers inside the battery is mainly longitudinal transmission. However, since the front electrode covers the light-receiving surface of the substrate, part of the incident light is reflected by the front electrode, which will cause optical loss and affect the energy conversion efficiency of the battery.

[0003] Compared with conventional solar cells, back-contact cells form alternating P-type doped regions and N-type doped regions on the backlit surface, with metal electrodes correspondingly covering the backlit surface. The current transmission of carriers inside the cell is mainly lateral transmission. Since there is no metal electrode blocking the light-receiving surface of the back-contact cell, shading losses can be avoided, which improves the conversion efficiency to a certain extent. However, due to the long lateral transmission distance, the lateral transmission of most carriers will cause significant series resistance loss, resulting in limited improvement in conversion efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a back-contact solar cell, a cell assembly and a photovoltaic system in view of the existing technical status.

[0005] The present invention can achieve a larger potential gradient between the P-type doped layer through the silicon substrate and then to the N-type doped layer, thereby strengthening the separation of photogenerated electron-hole pairs. The larger potential gradient is conducive to the rapid entry of electrons into the N-type doped layer and holes into the P-type doped layer, and the collected charges can be transmitted more quickly to the metal collection electrode corresponding to the metal grid line, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor. At the same time, the effective power generation area of ​​the silicon substrate is increased, more photogenerated carriers are generated, the short-circuit current is increased, and the battery conversion efficiency is effectively improved.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] First, the present invention provides a back-contact solar cell, comprising:

[0008] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0009] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0010] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0011] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer.

[0012] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0013] When the silicon substrate is a P-type silicon substrate, the total length of all the N-type electrodes is greater than the total length of all the P-type electrodes;

[0014] When the silicon substrate is an N-type silicon substrate, the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0015] In some embodiments:

[0016]

[0017] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0018] In some embodiments:

[0019]

[0020] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.01-1.15.

[0021] In some embodiments, when the silicon substrate is a P-type silicon substrate, a ratio a of the total length of all the N-type electrodes to the total length of all the P-type electrodes is 1<a≤1.5;

[0022] When the silicon substrate is an N-type silicon substrate, the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1<b≤1.5.

[0023] In some embodiments, when the silicon substrate is a P-type silicon substrate, a ratio a of a total length of all the N-type electrodes to a total length of all the P-type electrodes is 1.001≤a≤1.2;

[0024] When the silicon substrate is an N-type silicon substrate, a ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.001≤a≤1.2.

[0025] In some embodiments, the N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are arranged alternately and spaced along a second direction, and the first direction is arranged to intersect with the second direction.

[0026] The width of the first N-type doping region is greater than the width of the first P-type doping region.

[0027] In some embodiments, the N-type doping layer further includes a second N-type doping region, and a plurality of first N-type doping regions are arranged on the same second N-type doping region along the second direction; the P-type doping layer further includes a second P-type doping region, and a plurality of first P-type doping regions are arranged on the same second P-type doping region along the second direction; the length directions of the second N-type doping region and the second P-type doping region are arranged along the second direction, and between adjacent first N-type doping regions and first P-type doping regions, the second N-type doping regions and the second P-type doping regions are alternately arranged along the first direction;

[0028] The width of the second N-type doping region is greater than the width of the second P-type doping region.

[0029] In some embodiments, the N-type electrode includes a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region; the P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along the first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0030] In some embodiments, the N-type electrode includes a first N-type electrode and a second N-type electrode, the length direction of the first N-type electrode is set along the first direction, the length direction of the second N-type electrode is set along the second direction, the first N-type electrode is set outside the first N-type doping region, and the second N-type electrode is set outside the second N-type doping region; the P-type electrode includes a first P-type electrode and a second P-type electrode, the length direction of the first P-type electrode is set along the first direction, the length direction of the second P-type electrode is set along the second direction, the first P-type electrode is set outside the first P-type doping region, and the second P-type electrode is set outside the second P-type doping region.

[0031] In some embodiments, a ratio c of a width of the first N-type doping region to a width of the first P-type doping region is 1<c≤9.

[0032] In some embodiments, a ratio c of a width of the first N-type doping region to a width of the first P-type doping region is 1.4<c≤4.5.

[0033] In some embodiments, a width of the first P-type doping region is 100 μm to 900 μm.

[0034] In some embodiments, a width of the first P-type doping region is 200 μm to 500 μm.

[0035] In some embodiments, an isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate the two, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 0.3 mm to 3 mm.

[0036] In some embodiments, the sum of the widths of the single first N-type doping region, the two isolation regions, and the single first P-type doping region is 0.5 mm to 1.6 mm.

[0037] In some embodiments, the doping concentration of the silicon substrate is less than 5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0038] In some embodiments, a ratio between the conductivity of the P-type doping layer and the conductivity of the N-type doping layer is 1:2-6.5.

[0039] In some embodiments, the conductivity of the N-type doped layer is 600 ohm. -1 .cm -1 ~2800ohm -1 .cm -1 , the conductivity of the P-type doped layer is 150 ohm -1 .cm -1 ~580ohm -1 .cm -1 .

[0040] In some embodiments, the conductivity of the N-type doped layer is 1000 ohm. -1 .cm -1 ~1800ohm -1 .cm -1 , the conductivity of the P-type doped layer is 240ohm -1 .cm -1 ~450ohm -1 .cm-1 .

[0041] In some embodiments, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0042] In some embodiments, the square resistance of the P-type doped layer is 1.5 to 10 times the square resistance of the N-type doped layer.

[0043] In some embodiments, the sheet resistance of the N-type doped layer is 26 ohm / sq to 150 ohm / sq, and the sheet resistance of the P-type doped layer is 80 ohm / sq to 400 ohm / sq.

[0044] In some embodiments, the sheet resistance of the N-type doped layer is 35 ohm / sq to 120 ohm / sq, and the sheet resistance of the P-type doped layer is 90 ohm / sq to 350 ohm / sq.

[0045] In some embodiments, a passivation layer is further provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0046] Secondly, the present invention provides a battery assembly, including the above-mentioned back-contact solar cell.

[0047] Furthermore, the present invention provides a photovoltaic system, comprising the above-mentioned battery assembly.

[0048] The beneficial effects of the present invention are:

[0049] In the present invention, by controlling the conductivity of the N-type silicon substrate, the P-type doped layer and the N-type doped layer to increase in sequence, a larger potential gradient is achieved from the P-type doped layer through the silicon substrate to the N-type doped layer, thereby enhancing the separation of photogenerated electron-hole pairs. Among them, the one of the N-type doped layer and the P-type doped layer with the same polarity as the silicon substrate forms a high-low junction with the silicon substrate, and the one of the N-type doped layer and the P-type doped layer with a different polarity from the silicon substrate forms a pn junction with the silicon substrate. The larger potential gradient is conducive to the rapid entry of electrons into the N-type doped layer and the rapid entry of holes into the P-type doped layer, and the collected charges can be transmitted to the metal collection electrode corresponding to the metal gate line more quickly, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor; at the same time, by controlling the total length of the electrode corresponding to the one of the N-type doped layer and the P-type doped layer with a different polarity from the silicon substrate to be longer than the total length of the electrode corresponding to the one of the N-type doped layer and the P-type doped layer with the same polarity as the silicon substrate, the effective power generation area of ​​the silicon substrate is increased, more photogenerated carriers are generated, the short-circuit current is increased, and the battery conversion efficiency is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The figure is a schematic structural diagram of a back-contact solar cell of the present invention.

[0051] Figure 2 The present invention is a schematic structural diagram of a doping layer of a back contact solar cell.

[0052] Figure 3 Schematic diagram of the structure of the electrode layer of the present invention.

[0053] Figure 4 Another schematic diagram of the structure of a doping layer of a back contact solar cell of the present invention. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in further detail below.

[0055] First, see Figure 1 As shown, the present invention provides a back contact solar cell, comprising:

[0056] A silicon substrate 1, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0057] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0058] The doping layer includes an N-type doping layer 2 and a P-type doping layer 3 which are alternately arranged.

[0059] The electrode layer 5 includes an N-type electrode 51 and a P-type electrode 52, wherein the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same.

[0060] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0061] When the silicon substrate is a P-type silicon substrate, the total length of all the N-type electrodes is greater than the total length of all the P-type electrodes;

[0062] When the silicon substrate is an N-type silicon substrate, the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0063] In the present invention, by controlling the conductivity of the N-type silicon substrate, the P-type doped layer and the N-type doped layer to increase in sequence, a larger potential gradient is achieved from the P-type doped layer through the silicon substrate to the N-type doped layer, thereby enhancing the separation of photogenerated electron-hole pairs. Among them, the one of the N-type doped layer and the P-type doped layer with the same polarity as the silicon substrate forms a high-low junction with the silicon substrate, and the one of the N-type doped layer and the P-type doped layer with a different polarity from the silicon substrate forms a pn junction with the silicon substrate. The larger potential gradient is conducive to the rapid entry of electrons into the N-type doped layer and the rapid entry of holes into the P-type doped layer, and the collected charges can be transmitted to the metal collection electrode corresponding to the metal gate line more quickly, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor; at the same time, by controlling the total length of the electrode corresponding to the one of the N-type doped layer and the P-type doped layer with a different polarity from the silicon substrate to be longer than the total length of the electrode corresponding to the one of the N-type doped layer and the P-type doped layer with the same polarity as the silicon substrate, the effective power generation area of ​​the silicon substrate is increased, more photogenerated carriers are generated, the short-circuit current is increased, and the battery conversion efficiency is effectively improved.

[0064] Among them, the difference in conductivity between the N-type silicon substrate, the N-type doping layer and the P-type doping layer can be achieved by controlling the difference in doping concentrations of the N-type silicon substrate, the N-type dopant in the N-type doping layer and the P-type dopant in the P-type doping layer. The doping concentration is positively correlated with the conductivity. The P-type dopant in the P-type doping layer is mostly boron, and the N-type dopant in the N-type doping layer is mostly phosphorus. Highly doped phosphorus can maintain a good passivation effect and improve the battery conversion efficiency.

[0065] In some embodiments:

[0066]

[0067] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S Nis the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0068] When the silicon substrate is an N-type silicon substrate, the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes. In this case, the total contact area between all the P-type electrodes on the battery and the silicon substrate is greater than the total contact area between all the N-type electrodes on the battery and the silicon substrate. When the silicon substrate is a P-type silicon substrate, the total length of all the N-type electrodes is greater than the total length of all the P-type electrodes. In this case, the total contact area between all the N-type electrodes on the battery and the silicon substrate is greater than the total contact area between all the P-type electrodes on the battery and the silicon substrate. Furthermore, the total area of ​​the one of the N-type electrode and the P-type electrode with a different polarity from the silicon substrate is made greater than the total area of ​​the one of the N-type electrode and the P-type electrode with the same polarity as the silicon substrate, effectively improving the battery conversion efficiency.

[0069] In some embodiments:

[0070]

[0071] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.01-1.15.

[0072] Illustratively, k is 1.01, 1.02, 1.03, 1.04 or 1.05, but is not limited thereto.

[0073] When k is too small or too large, it is difficult to balance the collection of electron-hole pairs, affecting the battery conversion efficiency.

[0074] Wherein, when the silicon substrate is a P-type silicon substrate, the ratio a of the total length of all the N-type electrodes to the total length of all the P-type electrodes is 1<a≤1.5;

[0075] When the silicon substrate is an N-type silicon substrate, the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1<b≤1.5.

[0076] Exemplarily, when the silicon substrate is a P-type silicon substrate, the ratio a of the total length of all the N-type electrodes to the total length of all the P-type electrodes is 1.01, 1.05, 1.08, 1.1, 1.12, 1.15, 1.18, 1.2, 1.22, 1.25, 1.28, 1.3, 1.32, 1.35, 1.38, 1.4, 1.43, 1.45, 1.48 or 1.5, but is not limited to this.

[0077] Exemplarily, when the silicon substrate is an N-type silicon substrate, the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.01, 1.05, 1.08, 1.1, 1.12, 1.15, 1.18, 1.2, 1.22, 1.25, 1.28, 1.3, 1.32, 1.35, 1.38, 1.4, 1.43, 1.45, 1.48 or 1.5, but is not limited to this.

[0078] When a or b is too small, the effective power generation area is insufficient. When a or b is too large, it is difficult to balance the collection of electron-hole pairs, affecting the battery conversion efficiency.

[0079] Wherein, when the silicon substrate is a P-type silicon substrate, the ratio a of the total length of all the N-type electrodes to the total length of all the P-type electrodes is 1.001≤a≤1.2;

[0080] When the silicon substrate is an N-type silicon substrate, a ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.001≤a≤1.2.

[0081] Within this range, it is possible to better balance the collection of electron-hole pairs while ensuring sufficient effective power generation area.

[0082] Exemplarily, when the silicon substrate is a P-type silicon substrate, the ratio a of the total length of all the N-type electrodes to the total length of all the P-type electrodes is 1.001, 1.002, 1.005, 1.008, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19 or 1.2, but is not limited to this.

[0083] Exemplarily, when the silicon substrate is an N-type silicon substrate, the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.001, 1.002, 1.005, 1.008, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19 or 1.2, but is not limited to this.

[0084] The N-type doping layer includes a first N-type doping region 21, the P-type doping layer includes a first P-type doping region 31, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0085] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0086] The N-type doping layer further includes a second N-type doping region 22, and a plurality of first N-type doping regions are arranged on the same second N-type doping region along the second direction. The P-type doping layer further includes a second P-type doping region 32, and a plurality of first P-type doping regions are arranged on the same second P-type doping region along the second direction. The length directions of the second N-type doping region and the second P-type doping region are arranged along the second direction, and between adjacent first N-type doping regions and first P-type doping regions, the second N-type doping regions and the second P-type doping regions are alternately arranged along the first direction.

[0087] The width of the second N-type doping region is greater than the width of the second P-type doping region.

[0088] In a first specific embodiment, see Figures 2 to 3 As shown, the N-type doping layer and the P-type doping layer are rectangular structures. At this time, the N-type doping layer is the first N-type doping region, and the P-type doping layer is the first P-type doping region.

[0089] In a second specific embodiment, see Figure 4 As shown, the N-type doping layer and the P-type doping layer are comb-tooth structures. At this time, a single N-type doping layer is composed of a first N-type doping region and multiple second N-type doping regions, and multiple first N-type doping regions are arranged along the second direction on the same second N-type doping region. A single P-type doping layer is composed of a first P-type doping region and multiple second P-type doping regions, and multiple first P-type doping regions are arranged along the second direction on the same second P-type doping region.

[0090] Due to the high conductivity of the N-type doped layer compared to the P-type doped layer, the lateral transmission capacity of the N-type doped layer is stronger than that of the P-type doped layer, and the transmission distance is longer. Therefore, through the low-concentration doped silicon substrate, combined with the setting that the width of the N-type doped layer is greater than the width of the P-type doped layer, according to the corresponding lateral transmission capacity of the two, the carrier transmission distance is matched, and the current collection is balanced to obtain a smaller series resistance and a higher fill factor, further improving the conversion efficiency. At the same time, since the passivation characteristics of the highly doped N-type doped layer are better than those of the P-type doped layer, therefore, by reducing the width of the P-type doped layer and increasing the width of the N-type doped layer, the proportion of the passivation contact area of ​​the N-type polysilicon material layer is higher, which can make the overall comprehensive passivation level of the battery higher, the composite loss lower, and further improve the conversion efficiency.

[0091] When the N-type doping layer and the P-type doping layer are rectangular structures, the N-type electrode includes a first N-type electrode, and the P-type electrode includes a first P-type electrode.

[0092] Specifically, the N-type electrode includes a first N-type electrode 51, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0093] The P-type electrode includes a first P-type electrode 52 . The length direction of the first P-type electrode is arranged along a first direction. The first P-type electrode is arranged outside the first P-type doping region.

[0094] When the N-type doping layer and the P-type doping layer are in a comb-tooth structure, the N-type electrode includes a first N-type electrode and a second N-type electrode, and the P-type electrode includes a first P-type electrode and a second P-type electrode.

[0095] Specifically, the N-type electrode includes a first N-type electrode and a second N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, the length direction of the second N-type electrode is arranged along the second direction, the first N-type electrode is arranged outside the first N-type doping region, and the second N-type electrode is arranged outside the second N-type doping region;

[0096] The P-type electrode includes a first P-type electrode and a second P-type electrode, the length direction of the first P-type electrode is set along the first direction, the length direction of the second P-type electrode is set along the second direction, the first P-type electrode is set outside the first P-type doping region, and the second P-type electrode is set outside the second P-type doping region.

[0097] Wherein, a ratio c of a width of the first N-type doping region to a width of the first P-type doping region is 1<c≤9.

[0098] Illustratively, c is 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 or 9, but is not limited thereto.

[0099] When the ratio between the width of the first N-type doping region and the width of the first P-type doping region is too low, the improvement effect of the series resistance and the fill factor is not good. When the ratio between the width of the first N-type doping region and the width of the first P-type doping region is too high, the width of the first P-type doping region is too narrow and the short-circuit current is too low, which affects the conversion efficiency.

[0100] Wherein, a ratio c of a width of the first N-type doping region to a width of the first P-type doping region is 1.4<c≤4.5.

[0101] Illustratively, c is 1.4, 1.5, 1.8, 2, 2.2, 2.5, 2.7, 3, 3.3, 3.5, 3.8, 4, 4.2 or 4.5, but is not limited thereto.

[0102] Within this range, smaller series resistance and higher fill factor can be obtained.

[0103] Wherein, the width of the first P-type doping region is 100 μm to 900 μm.

[0104] When the width of the first P-type doping region is too large, the first N-type doping region needs to be set to a larger width, which leads to an increase in the total width of the N-type doping layer and the P-type doping layer, an increase in the lateral transport distance of the carriers, and an increase in the recombination loss during the transport process. The number of N-type doping layers and P-type doping layers that can be arranged in the same battery decreases, and the number of corresponding metal grid lines (electrode layers) set on the outside decreases accordingly, and the current collection capacity decreases, affecting the conversion efficiency.

[0105] Exemplarily, the width of the first P-type doping region is 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, 650μm, 700μm, 750μm, 800μm, 850μm or 900μm, but is not limited thereto.

[0106] Preferably, the width of the first P-type doping region is 200 μm to 500 μm. Within this range, a smaller series resistance and a higher fill factor can be obtained.

[0107] Wherein, an isolation region 6 for separating the adjacent first N-type doping region and the first P-type doping region is provided, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 0.3 mm to 3 mm, wherein the width of the isolation region is W G.

[0108] Illustratively, the cell width is 0.3 mm, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm or 3.0 mm, but is not limited thereto.

[0109] On the basis of controlling the width and total area ratio of the first N-type doping region and the first P-type doping region, the unit width can be further controlled to maximize charge collection. Within this unit width range, the lateral transport distance of carriers is further shortened, the series resistance is reduced, the fill factor is improved, and the battery conversion efficiency is effectively improved.

[0110] When the unit width is too small, the difficulty of preparation increases, and it is easy to cause the N-type doped layer and the P-type doped layer to overlap. At the same time, due to technical limitations, the isolation area has a narrowest width. When the unit width is too small, it is easy for the isolation area to occupy too large a proportion of the entire unit width, and the surface recombination loss of the isolation area increases, which will cause the battery conversion efficiency to decrease.

[0111] When the cell width is too large, the electric field strength between the N-type doped layer and the P-type doped layer is weakened, the lateral transport distance is extended, it is difficult to form effective carrier collection, and the battery conversion efficiency decreases.

[0112] Among them, the sum of the widths of a single first N-type doping region, two of the isolation regions and a single first P-type doping region is 0.5 mm to 1.6 mm. Within this range, the battery conversion efficiency is high and the preparation difficulty is relatively low, ensuring a higher production yield and better overall performance.

[0113] Exemplarily, the cell width is 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm or 1.6 mm, but is not limited thereto.

[0114] Wherein, the doping concentration of the silicon substrate is less than 5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0115] In the present invention, the silicon substrate is doped at a low concentration to form a silicon substrate with low conductivity, thereby forming a large conductivity difference between the silicon substrate and the N-type doped layer and the P-type doped layer. The N-type doped layer and the P-type doped layer are set with high conductivity compared to the silicon substrate. This high conductivity difference setting enables the N-type doped layer and the P-type doped layer to form a large potential gradient with the low-doped and low-conductivity silicon substrate, respectively, to enhance the electric field strength, to more effectively separate electrons and holes, and to strengthen the lateral transmission ability of carriers.

[0116] Among them, the ratio between the conductivity of the P-type doped layer and the N-type doped layer is 1:2~6.5, thereby forming a sufficiently large conductivity difference between the N-type doped layer and the P-type doped layer, which is conducive to forming a larger potential gradient between the P-type doped layer and the low-doped, low-conductivity silicon substrate.

[0117] Exemplarily, the ratio between the conductivity of the P-type doped layer and the N-type doped layer is 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6 or 1:6.5, but is not limited thereto.

[0118] Wherein, the conductivity of the N-type doped layer is 600 ohm -1 .cm -1 ~2800ohm -1 .cm -1 , the conductivity of the P-type doped layer is 150 ohm -1 .cm -1 ~580ohm -1 .cm -1 .

[0119] When the conductivity of the N-type doped layer or the conductivity of the P-type doped layer is too low, the current transmission efficiency is reduced, which can easily increase the surface recombination efficiency and the recombination loss during the transmission process, resulting in a decrease in conversion efficiency. When the conductivity of the N-type doped layer or the conductivity of the P-type doped layer is too high, the preparation difficulty increases, which can easily reduce the lattice quality and affect the conversion efficiency.

[0120] Exemplarily, the conductivity of the N-type doped layer is 600 ohm -1 .cm -1 、650ohm -1 .cm -1 、700ohm -1 .cm -1 、750ohm -1 .cm -1 、800ohm -1 .cm -1 、850ohm -1 .cm -1 、900ohm -1 .cm -1 、950ohm -1 .cm -1 、1000ohm - 1 .cm -1 、1050ohm -1 .cm -1 、1100ohm -1 .cm -1、1150ohm -1 .cm -1 、1200ohm -1 .cm -1 、1250ohm -1 .cm -1 、1300ohm -1 .cm -1 、1350ohm -1 .cm -1 、1400ohm -1 .cm -1 、1450ohm -1 .cm -1 、1500ohm -1 .cm -1 、1550ohm -1 .cm -1 、1600ohm -1 .cm -1 、1650ohm -1 .cm -1 、1700ohm -1 .cm -1 、1750ohm -1 .cm -1 、1800ohm -1 .cm -1 、1850ohm -1 .cm -1 、1900ohm -1 .cm -1 、1950ohm -1 .cm -1 、2000ohm -1 .cm -1 、2100ohm -1 .cm -1 、2150ohm -1 .cm -1 、2200ohm -1 .cm -1 、2250ohm -1 .cm -1 、2300ohm -1 .cm -1 、2350ohm -1 .cm -1 、2400ohm -1 .cm -1 、2450ohm -1 .cm -1 、2500ohm -1 .cm -1、2550ohm -1 .cm -1 、2600ohm -1 .cm -1 、2650ohm -1 .cm -1 、2700ohm -1 .cm -1 、2750ohm -1 .cm -1 or 2800ohm -1 .cm -1 , but not limited to this.

[0121] For example, the conductivity of the P-type doped layer is 150 ohm. -1 .cm -1 、180ohm -1 .cm -1 、200ohm -1 .cm -1 、220ohm -1 .cm -1 、250ohm -1 .cm -1 、280ohm -1 .cm -1 、300ohm -1 .cm -1 、320ohm -1 .cm -1 、350ohm -1 .cm -1 、380ohm -1 .cm -1 、400ohm -1 .cm -1 、420ohm -1 .cm -1 、450ohm -1 .cm -1 、480ohm -1 .cm -1 、500ohm -1 .cm -1 、520ohm -1 .cm -1 、550ohm -1 .cm -1 or 580ohm -1 .cm -1 , but not limited to this.

[0122] Wherein, the conductivity of the N-type doped layer is 1000 ohm -1 .cm -1~1800ohm -1 .cm -1 , the conductivity of the P-type doped layer is 240ohm -1 .cm -1 ~450ohm -1 .cm -1 .

[0123] For example, the conductivity of the N-type doped layer is 1000 hm -1 .cm -1 、1050ohm -1 .cm -1 、1100ohm - 1 .cm -1 、1120ohm -1 .cm -1 、1150ohm -1 .cm -1 、1180ohm -1 .cm -1 、1200ohm -1 .cm -1 、1230ohm -1 .cm -1 、1250ohm -1 .cm -1 、1280ohm -1 .cm -1 、1300ohm -1 .cm -1 、1320ohm -1 .cm -1 、1350ohm -1 .cm -1 、1380ohm -1 .cm -1 、1400ohm -1 .cm -1 、1420ohm -1 .cm -1 、1450ohm -1 .cm -1 、1480ohm -1 .cm -1 、1500ohm -1 .cm -1 、1520ohm -1 .cm -1 、1550ohm -1 .cm -1 、1580ohm -1 .cm -1 、1600ohm-1 .cm -1 、1620ohm -1 .cm -1 、1650ohm -1 .cm -1 、1680ohm -1 .cm -1 、1700ohm -1 .cm -1 、1720ohm -1 .cm -1 、1750ohm -1 .cm -1 、1780ohm -1 .cm -1 or 1800ohm -1 .cm -1 , but not limited to this.

[0124] For example, the conductivity of the P-type doped layer is 240 ohm. -1 .cm -1 、250ohm -1 .cm -1 、280ohm -1 .cm -1 、300ohm -1 .cm -1 、320ohm -1 .cm -1 、350ohm -1 .cm -1 、380ohm -1 .cm -1 、400ohm -1 .cm -1 、420ohm -1 .cm -1 or 450ohm -1 .cm -1 , but not limited to this.

[0125] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0126] The N-type doped layer has low square resistance and stronger lateral transport capability than the P-type doped layer. The width of the first N-type doped region can be set to be larger than the width of the first P-type doped region, thereby improving series resistance and fill factor while balancing current collection, thereby improving conversion efficiency.

[0127] The square resistance of the P-type doped layer is 1.5 to 10 times that of the N-type doped layer.

[0128] Exemplarily, the square resistance of the P-type doped layer is 1.5 times, 2.0 times, 2.5 times, 3.0 times, 3.5 times, 4.0 times, 4.5 times, 5.0 times, 5.5 times, 6.0 times, 6.5 times, 7.0 times, 7.5 times, 8.0 times, 8.5 times, 9.0 times, 9.5 times or 10 times the square resistance of the N-type doped layer, but is not limited to this.

[0129] The sheet resistance of the N-type doped layer is 26 ohm / sq to 150 ohm / sq, and the sheet resistance of the P-type doped layer is 80 ohm / sq to 400 ohm / sq.

[0130] Exemplarily, the square resistance of the N-type doped layer is 26ohm / sq, 30ohm / sq, 35ohm / sq, 40ohm / sq, 45ohm / sq, 50ohm / sq, 55ohm / sq, 60ohm / sq, 65ohm / sq, 70ohm / sq, 75ohm / sq, 80ohm / sq, 85ohm / sq, 90ohm / sq, 95ohm / sq, 100ohm / sq, 105ohm / sq, 110ohm / sq, 115ohm / sq, 120ohm / sq, 125ohm / sq, 130ohm / sq, 135ohm / sq, 140ohm / sq, 145ohm / sq or 150ohm / sq, but is not limited to this.

[0131] For example, the square resistance of the P-type doped layer is 80 ohm / sq, 90 ohm / sq, 100 ohm / sq, 110 ohm / sq, 120 ohm / sq, 130 ohm / sq, 140 ohm / sq, 150 ohm / sq, 160 ohm / sq, 170 ohm / sq, 180 ohm / sq, 190 ohm / sq, 200 ohm / sq, 210 ohm / sq, 220 ohm / sq, 230 ohm / sq, 240 ohm / sq, 250 ohm / sq, 260 ohm / sq, 270 ohm / sq, 280 ohm / sq, 290 ohm / sq, 300 ohm / sq, 310 ohm / sq, 320 ohm / sq, 330 ohm / sq, 340 ohm / sq, 350 ohm / sq, 360 ohm / sq, 370 ohm / sq, 380 ohm / sq, 390 ohm / sq, 400 ohm / sq, 410 ohm / sq, 420 ohm / sq, 430 ohm / sq, 440 ohm sq, 350ohm / sq, 360ohm / sq, 370ohm / sq, 380ohm / sq, 390ohm / sq or 400ohm / sq, but not limited to, 40ohm / sq, 250ohm / sq, 260ohm / sq, 270ohm / sq, 280ohm / sq, 290ohm / sq, 300ohm / sq, 310ohm / sq, 320ohm / sq, 330ohm / sq, 340ohm / sq, 350ohm / sq, 360ohm / sq, 370ohm / sq, 380ohm / sq, 390ohm / sq or 400ohm / sq.

[0132] The sheet resistance of the N-type doped layer is 35 ohm / sq to 120 ohm / sq, and the sheet resistance of the P-type doped layer is 90 ohm / sq to 350 ohm / sq.

[0133] Exemplarily, the square resistance of the N-type doped layer is 35ohm / sq, 40ohm / sq, 45ohm / sq, 50ohm / sq, 55ohm / sq, 60ohm / sq, 65ohm / sq, 70ohm / sq, 75ohm / sq, 80ohm / sq, 85ohm / sq, 90ohm / sq, 95ohm / sq, 100ohm / sq, 105ohm / sq, 110ohm / sq, 115ohm / sq or 120ohm / sq, but is not limited to this.

[0134] Exemplarily, the square resistance of the P-type doped layer is 90 ohm / sq, 100 ohm / sq, 110 ohm / sq, 120 ohm / sq, 130 ohm / sq, 140 ohm / sq, 150 ohm / sq, 160 ohm / sq, 170 ohm / sq, 180 ohm / sq, 190 ohm / sq, 200 ohm / sq, 210 ohm / sq, 220ohm / sq, 230ohm / sq, 240ohm / sq, 250ohm / sq, 260ohm / sq, 270ohm / sq, 280ohm / sq, 290ohm / sq, 300ohm / sq, 310ohm / sq, 320ohm / sq, 330ohm / sq, 340ohm / sq or 350ohm / sq, but not limited to these.

[0135] A passivation layer 4 is further provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0136] The passivation layer may be at least one of a silicon nitride material layer, a silicon oxide material layer, a silicon oxynitride material layer, and an intrinsic amorphous silicon material layer.

[0137] The passivation layer effectively reduces the recombination of minority carriers and surface states on the back of the battery, which helps to improve the photoelectric conversion efficiency of the battery.

[0138] Secondly, the present invention provides a battery assembly, including the above-mentioned back-contact solar cell.

[0139] Furthermore, the present invention provides a photovoltaic system, comprising the above-mentioned battery assembly.

[0140] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0141] Example 1

[0142] First, this embodiment discloses a back-contact solar cell, comprising:

[0143] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0144] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0145] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0146] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0147] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0148] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0149] in,

[0150] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0151] in,

[0152] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.05.

[0153] The silicon substrate is an N-type silicon substrate, and the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.002.

[0154] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0155] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0156] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0157] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0158] Wherein, a ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 4.5.

[0159] Wherein, the width of the first P-type doping region is 500 μm.

[0160] An isolation region for separating the adjacent first N-type doping region and the first P-type doping region is provided between the two adjacent first N-type doping regions, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 2.85 mm.

[0161] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0162] The ratio of the conductivity of the P-type doping layer to the conductivity of the N-type doping layer is 1:3.53.

[0163] Wherein, the conductivity of the N-type doped layer is 600 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 170 ohm -1 .cm -1 .

[0164] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0165] The square resistance of the P-type doped layer is 2.71 times that of the N-type doped layer.

[0166] The sheet resistance of the N-type doped layer is 140 ohm / sq, and the sheet resistance of the P-type doped layer is 380 ohm / sq.

[0167] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0168] Secondly, this embodiment discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0169] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.

[0170] Example 2

[0171] First, this embodiment discloses a back-contact solar cell, comprising:

[0172] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0173] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0174] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0175] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0176] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0177] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0178] in,

[0179] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0180] in,

[0181] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.1.

[0182] The silicon substrate is an N-type silicon substrate, and a ratio b of a total length of all the P-type electrodes to a total length of all the N-type electrodes is 1.05.

[0183] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0184] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0185] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0186] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0187] The ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 3.

[0188] Wherein, the width of the first P-type doping region is 300 μm.

[0189] An isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate the two, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 1.3 mm.

[0190] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0191] The ratio of the conductivity of the P-type doping layer to the conductivity of the N-type doping layer is 1:4.17.

[0192] Wherein, the conductivity of the N-type doped layer is 1000 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 240ohm -1 .cm -1 .

[0193] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0194] The square resistance of the P-type doped layer is 4.2 times that of the N-type doped layer.

[0195] The sheet resistance of the N-type doped layer is 50 ohm / sq, and the sheet resistance of the P-type doped layer is 210 ohm / sq.

[0196] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0197] Secondly, this embodiment discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0198] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.

[0199] Example 3

[0200] First, this embodiment discloses a back-contact solar cell, comprising:

[0201] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0202] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0203] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0204] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0205] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0206] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0207] in,

[0208] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0209] in,

[0210] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.1.

[0211] The silicon substrate is an N-type silicon substrate, and the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.05.

[0212] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0213] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0214] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0215] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0216] The ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 3.

[0217] Wherein, the width of the first P-type doping region is 300 μm.

[0218] An isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate the two, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 1.3 mm.

[0219] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0220] The ratio of the conductivity of the P-type doped layer to the conductivity of the N-type doped layer is 1:4.83.

[0221] Wherein, the conductivity of the N-type doped layer is 2800 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 580 ohm -1 .cm -1 .

[0222] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0223] The square resistance of the P-type doped layer is 2.81 times that of the N-type doped layer.

[0224] The sheet resistance of the N-type doped layer is 32 ohm / sq, and the sheet resistance of the P-type doped layer is 90 ohm / sq.

[0225] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0226] Secondly, this embodiment discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0227] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.

[0228] Example 4

[0229] First, this embodiment discloses a back-contact solar cell, comprising:

[0230] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0231] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0232] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0233] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0234] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0235] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0236] in,

[0237] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0238] in,

[0239] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.1.

[0240] The silicon substrate is an N-type silicon substrate, and a ratio b of a total length of all the P-type electrodes to a total length of all the N-type electrodes is 1.05.

[0241] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0242] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0243] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0244] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0245] The ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 3.

[0246] Wherein, the width of the first P-type doping region is 300 μm.

[0247] An isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate the two, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 1.3 mm.

[0248] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0249] Wherein, the ratio between the conductivity of the P-type doping layer and the conductivity of the N-type doping layer is 1:6.

[0250] Wherein, the conductivity of the N-type doped layer is 1800 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 300ohm -1 .cm -1 .

[0251] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0252] The square resistance of the P-type doped layer is 7.5 times that of the N-type doped layer.

[0253] The sheet resistance of the N-type doped layer is 28 ohm / sq, and the sheet resistance of the P-type doped layer is 21 ohm / sq.

[0254] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0255] Secondly, this embodiment discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0256] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.

[0257] Example 5

[0258] First, this embodiment discloses a back-contact solar cell, comprising:

[0259] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0260] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0261] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0262] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0263] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0264] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0265] in,

[0266] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0267] in,

[0268] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.1.

[0269] The silicon substrate is an N-type silicon substrate, and a ratio b of a total length of all the P-type electrodes to a total length of all the N-type electrodes is 1.05.

[0270] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0271] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0272] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0273] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0274] The ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 1.5.

[0275] Wherein, the width of the first P-type doping region is 900 μm.

[0276] An isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate the two, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 2.35 mm.

[0277] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0278] Wherein, the ratio between the conductivity of the P-type doping layer and the conductivity of the N-type doping layer is 1:4.

[0279] Wherein, the conductivity of the N-type doped layer is 1800 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 450ohm -1 .cm -1 .

[0280] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0281] The square resistance of the P-type doped layer is 5 times that of the N-type doped layer.

[0282] The sheet resistance of the N-type doped layer is 28 ohm / sq, and the sheet resistance of the P-type doped layer is 140 ohm / sq.

[0283] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0284] Secondly, this embodiment discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0285] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.

[0286] Example 6

[0287] First, this embodiment discloses a back-contact solar cell, comprising:

[0288] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0289] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0290] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0291] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0292] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0293] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0294] in,

[0295] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0296] in,

[0297] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.13.

[0298] The silicon substrate is an N-type silicon substrate, and the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.08.

[0299] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0300] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0301] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0302] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0303] Wherein, a ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 9.

[0304] Wherein, the width of the first P-type doping region is 100 μm.

[0305] An isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate the two, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 1.1 mm.

[0306] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0307] Wherein, the ratio between the conductivity of the P-type doping layer and the conductivity of the N-type doping layer is 1:4.

[0308] Wherein, the conductivity of the N-type doped layer is 1800 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 450ohm -1 .cm -1 .

[0309] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0310] The square resistance of the P-type doped layer is 5 times that of the N-type doped layer.

[0311] The sheet resistance of the N-type doped layer is 28 ohm / sq, and the sheet resistance of the P-type doped layer is 1400 ohm / sq.

[0312] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0313] Secondly, this embodiment discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0314] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.

[0315] Example 7

[0316] First, this embodiment discloses a back-contact solar cell, comprising:

[0317] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0318] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0319] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0320] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0321] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0322] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0323] in,

[0324] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0325] in,

[0326] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.15.

[0327] The silicon substrate is an N-type silicon substrate, and a ratio b of a total length of all the P-type electrodes to a total length of all the N-type electrodes is 1.1.

[0328] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0329] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0330] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0331] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0332] The ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 3.

[0333] Wherein, the width of the first P-type doping region is 300 μm.

[0334] An isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate the two, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 1.3 mm.

[0335] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0336] Wherein, the ratio between the conductivity of the P-type doping layer and the conductivity of the N-type doping layer is 1:6.

[0337] Wherein, the conductivity of the N-type doped layer is 1800 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 300ohm -1 .cm -1 .

[0338] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0339] The square resistance of the P-type doped layer is 7.5 times that of the N-type doped layer.

[0340] The sheet resistance of the N-type doped layer is 28 ohm / sq, and the sheet resistance of the P-type doped layer is 210 ohm / sq.

[0341] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0342] Secondly, this embodiment discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0343] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.

[0344] Example 8

[0345] First, this embodiment discloses a back-contact solar cell, comprising:

[0346] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0347] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0348] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0349] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0350] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0351] The silicon substrate is a P-type silicon substrate, and the total length of all the N-type electrodes is greater than the total length of all the P-type electrodes.

[0352] in,

[0353] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0354] in,

[0355] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.15.

[0356] The silicon substrate is a P-type silicon substrate, and the ratio a of the total length of all the N-type electrodes to the total length of all the P-type electrodes is 1.2.

[0357] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0358] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0359] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0360] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0361] Wherein, a ratio c of a width of the first N-type doping region to a width of the first P-type doping region is 1<c≤9.

[0362] Wherein, the width of the first P-type doping region is 300 μm.

[0363] An isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate the two, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 1.3 mm.

[0364] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0365] Wherein, the ratio between the conductivity of the P-type doping layer and the conductivity of the N-type doping layer is 1:6.

[0366] Wherein, the conductivity of the N-type doped layer is 1800 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 300ohm -1 .cm -1 .

[0367] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0368] The square resistance of the P-type doped layer is 7.5 times that of the N-type doped layer.

[0369] The sheet resistance of the N-type doped layer is 28 ohm / sq, and the sheet resistance of the P-type doped layer is 210 ohm / sq.

[0370] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0371] Secondly, this embodiment discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0372] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.

[0373] Comparative Example 1

[0374] First, this comparative example discloses a back-contact solar cell, comprising:

[0375] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0376] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0377] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0378] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0379] The electrical conductivities of the silicon substrate, the N-type doped layer, and the P-type doped layer increase in sequence.

[0380] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

[0381] in,

[0382] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

[0383] in,

[0384] Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.05.

[0385] The silicon substrate is an N-type silicon substrate, and the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.002.

[0386] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0387] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0388] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0389] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0390] Wherein, a ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 4.5.

[0391] Wherein, the width of the first P-type doping region is 500 μm.

[0392] An isolation region for separating the adjacent first N-type doping region and the first P-type doping region is provided between the two adjacent first N-type doping regions, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 2.85 mm.

[0393] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0394] The ratio of the conductivity of the P-type doping layer to the conductivity of the N-type doping layer is 1.93:1.

[0395] Wherein, the conductivity of the N-type doped layer is 300 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 580 ohm -1 .cm -1 .

[0396] The square resistance of the P-type doped layer is 0.53 times the square resistance of the N-type doped layer.

[0397] The sheet resistance of the N-type doped layer is 170 ohm / sq, and the sheet resistance of the P-type doped layer is 90 ohm / sq.

[0398] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0399] Secondly, this comparative example discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0400] Furthermore, this comparative example discloses a photovoltaic system, including the above-mentioned battery assembly.

[0401] Comparative Example 2

[0402] First, this embodiment discloses a back-contact solar cell, comprising:

[0403] A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other;

[0404] The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface.

[0405] The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged.

[0406] The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer, wherein the widths of the N-type electrode and the P-type electrode are the same,

[0407] The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence.

[0408] The silicon substrate is an N-type silicon substrate, and the total length of all the P-type electrodes is less than the total length of all the N-type electrodes.

[0409] Among them, S P ·k·S N

[0410] In the formula, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 0.85.

[0411] The silicon substrate is an N-type silicon substrate, and the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1:1.002.

[0412] The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction.

[0413] The width W of the first N-type doping region N Greater than the width W of the first P-type doping region P .

[0414] The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region;

[0415] The P-type electrode includes a first P-type electrode, the length direction of the first P-type electrode is arranged along a first direction, and the first P-type electrode is arranged outside the first P-type doping region.

[0416] Wherein, a ratio c of the width of the first N-type doping region to the width of the first P-type doping region is 4.5.

[0417] Wherein, the width of the first P-type doping region is 500 μm.

[0418] An isolation region for separating the adjacent first N-type doping region and the first P-type doping region is provided between the two adjacent first N-type doping regions, and the sum of the widths of a single first N-type doping region, two isolation regions, and a single first P-type doping region is 2.85 mm.

[0419] The doping concentration of the silicon substrate is 4.5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

[0420] The ratio of the conductivity of the P-type doping layer to the conductivity of the N-type doping layer is 1:3.53.

[0421] Wherein, the conductivity of the N-type doped layer is 600 ohm -1 .cm -1 , the conductivity of the P-type doped layer is 170 ohm -1 .cm -1 .

[0422] Wherein, the sheet resistance of the P-type doped layer is greater than the sheet resistance of the N-type doped layer.

[0423] The square resistance of the P-type doped layer is 2.71 times that of the N-type doped layer.

[0424] The sheet resistance of the N-type doped layer is 140 ohm / sq, and the sheet resistance of the P-type doped layer is 380 ohm / sq.

[0425] A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

[0426] Secondly, this comparative example discloses a battery assembly, including the above-mentioned back-contact solar cell.

[0427] Furthermore, this comparative example discloses a photovoltaic system, including the above-mentioned battery assembly.

[0428] The solar cells prepared in Examples 1 to 8 and Comparative Examples 1 to 2 were subjected to performance tests, and the test results are as follows:

[0429]

[0430] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the field can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A back contact solar cell, characterized in that: include: A silicon substrate, wherein the silicon substrate has a light-receiving surface and a backlight surface opposite to each other; The backlight surface is provided with a doping layer and an electrode layer in sequence in a direction away from the light receiving surface. The doping layer includes N-type doping layers and P-type doping layers that are alternately arranged. The electrode layer includes an N-type electrode and a P-type electrode, the N-type electrode is electrically connected to the N-type doped layer, and the P-type electrode is electrically connected to the P-type doped layer. The electrical conductivities of the silicon substrate, the P-type doped layer, and the N-type doped layer increase in sequence. When the silicon substrate is a P-type silicon substrate, the total length of all the N-type electrodes is greater than the total length of all the P-type electrodes; When the silicon substrate is an N-type silicon substrate, the total length of all the P-type electrodes is greater than the total length of all the N-type electrodes.

2. A back contact solar cell according to claim 1, characterized in that: Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P It is the total contact area between all the P-type electrodes on the battery and the silicon substrate.

3. A back contact solar cell according to claim 1, characterized in that: Where, L N is the total length of all the N-type electrodes, L P is the total length of all the P-type electrodes, S N is the total contact area between all the N-type electrodes on the battery and the silicon substrate, S P is the total contact area between all the P-type electrodes on the battery and the silicon substrate, k is a coefficient, and k is 1.01-1.

15.

4. A back contact solar cell according to claim 1, characterized in that: When the silicon substrate is a P-type silicon substrate, a ratio a of the total length of all the N-type electrodes to the total length of all the P-type electrodes is 1<a≤1.5; When the silicon substrate is an N-type silicon substrate, the ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1<b≤1.

5.

5. A back contact solar cell according to claim 4, characterized in that: When the silicon substrate is a P-type silicon substrate, a ratio a of the total length of all the N-type electrodes to the total length of all the P-type electrodes is 1.001≤a≤1.2; When the silicon substrate is an N-type silicon substrate, a ratio b of the total length of all the P-type electrodes to the total length of all the N-type electrodes is 1.001≤a≤1.

2.

6. A back contact solar cell according to claim 1, characterized in that: The N-type doping layer includes a first N-type doping region, the P-type doping layer includes a first P-type doping region, the length directions of the first N-type doping region and the first P-type doping region are both arranged along a first direction, the first N-type doping region and the first P-type doping region are alternately arranged along a second direction, and the first direction is arranged to intersect with the second direction, The width of the first N-type doping region is greater than the width of the first P-type doping region.

7. A back contact solar cell according to claim 6, characterized in that: The N-type doping layer further includes a second N-type doping region, and a plurality of first N-type doping regions are arranged on the same second N-type doping region along the second direction. The P-type doping layer further includes a second P-type doping region, and a plurality of first P-type doping regions are arranged on the same second P-type doping region along the second direction. The length directions of the second N-type doping region and the second P-type doping region are arranged along the second direction, and between adjacent first N-type doping regions and first P-type doping regions, the second N-type doping regions and the second P-type doping regions are alternately arranged along the first direction. The width of the second N-type doping region is greater than the width of the second P-type doping region.

8. A back contact solar cell according to claim 7, characterized in that: The N-type electrode comprises a first N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, and the first N-type electrode is arranged outside the first N-type doping region; the P-type electrode comprises a first P-type electrode, the length direction of the first P-type electrode is arranged along the first direction, and the first P-type electrode is arranged outside the first P-type doping region; Alternatively, the N-type electrode includes a first N-type electrode and a second N-type electrode, the length direction of the first N-type electrode is arranged along the first direction, the length direction of the second N-type electrode is arranged along the second direction, the first N-type electrode is arranged outside the first N-type doping region, and the second N-type electrode is arranged outside the second N-type doping region; the P-type electrode includes a first P-type electrode and a second P-type electrode, the length direction of the first P-type electrode is arranged along the first direction, the length direction of the second P-type electrode is arranged along the second direction, the first P-type electrode is arranged outside the first P-type doping region, and the second P-type electrode is arranged outside the second P-type doping region.

9. A back contact solar cell according to claim 6, characterized in that: A ratio c of a width of the first N-type doping region to a width of the first P-type doping region is 1<c≤9.

10. A back contact solar cell according to claim 9, characterized in that: A ratio c of a width of the first N-type doping region to a width of the first P-type doping region is 1.4<c≤4.

5.

11. A back contact solar cell according to claim 6, characterized in that: The width of the first P-type doping region is 100 μm to 900 μm.

12. A back contact solar cell according to claim 11, characterized in that: The width of the first P-type doping region is 200 μm to 500 μm.

13. A back contact solar cell according to claim 6, characterized in that: An isolation region is provided between adjacent first N-type doping regions and first P-type doping regions to separate them. The sum of the widths of a single first N-type doping region, two isolation regions and a single first P-type doping region is 0.3 mm to 3 mm.

14. A back contact solar cell according to claim 13, characterized in that: The sum of the widths of a single first N-type doping region, two of the isolation regions, and a single first P-type doping region is 0.5 mm to 1.6 mm.

15. The back contact solar cell according to claim 1, characterized in that: The doping concentration of the silicon substrate is less than 5×10 14 cm -3 , the electrical conductivity of the silicon substrate is less than 2S / cm.

16. A back contact solar cell according to claim 1, characterized in that: The ratio of the conductivity of the P-type doping layer to the conductivity of the N-type doping layer is 1:2 to 6.

5.

17. A back contact solar cell according to claim 1, characterized in that: The conductivity of the N-type doped layer is 600 ohm -1 .cm -1 ~2800ohm -1 .cm -1 , the conductivity of the P-type doped layer is 150 ohm -1 .cm -1 ~580ohm -1 .cm -1 .

18. A back contact solar cell according to claim 17, characterized in that: The conductivity of the N-type doped layer is 1000 ohm -1 .cm -1 ~1800ohm -1 .cm -1 , the conductivity of the P-type doped layer is 240ohm -1 .cm -1 ~450ohm - 1 .cm -1 .

19. The back contact solar cell according to claim 1, characterized in that: The sheet resistance of the P-type doping layer is greater than the sheet resistance of the N-type doping layer.

20. A back contact solar cell according to claim 19, characterized in that: The square resistance of the P-type doping layer is 1.5 to 10 times that of the N-type doping layer.

21. A back contact solar cell according to claim 19, characterized in that: The sheet resistance of the N-type doped layer is 26 ohm / sq to 150 ohm / sq, and the sheet resistance of the P-type doped layer is 80 ohm / sq to 400 ohm / sq.

22. A back contact solar cell according to claim 20, characterized in that: The sheet resistance of the N-type doped layer is 35 ohm / sq to 120 ohm / sq, and the sheet resistance of the P-type doped layer is 90 ohm / sq to 350 ohm / sq.

23. A back contact solar cell according to claim 1, characterized in that: A passivation layer is also provided on the backlight surface, and the passivation layer is provided on the side of the N-type doped layer and the P-type doped layer facing away from the silicon substrate, and the passivation layer is provided with a first window and a second window, the N-type electrode at least partially extends into the first window and contacts the N-type doped layer, and the P-type electrode at least partially extends into the second window and contacts the P-type doped layer.

24. A battery assembly, characterized in that: Comprising a back-contact solar cell according to any one of claims 1 to 23.

25. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 24.

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