Back contact cell edge connection grid line structure

Abstract

The utility model relates to the photovoltaic field, and discloses a back contact cell edge connection grid line structure, which comprises an edge main grid region, a first auxiliary grid region, a PAD point region and a connection grid line region, the edge main gate region and the PAD point region are located on the two transverse sides of the connecting gate line region and are connected through the connecting gate line region. The two first auxiliary gate regions are symmetrically arranged on the two longitudinal sides of the connecting gate line region; a second corrosive slurry layer is arranged on the surface of the central area of the connecting grid line area; non-corrosive slurry layers are arranged on the surfaces of the non-central area of the connecting grid line area, the edge main grid area and the PAD point area; a second non-corrosive slurry layer is arranged on the surface of the second corrosive slurry layer connected with the grid line area; the surface of the first auxiliary grid region is provided with a first corrosive slurry layer. The second corrosive slurry layer and the second non-corrosive slurry layer are successively arranged on the surface of the central area of the connecting grid line area, so that on one hand, the line resistance of the whole connecting grid line can be reduced, and the edge main grid current is fully led out; and on the other hand, gold / semi-compounding caused by corrosive slurry can be reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic field especially, relate to a kind of back contact cell edge connection grid line structure. BACKGROUND

[0002] ‌The PAD point of back contact cell refers to the metal contact point located on the back of the cell, which is used to connect with the solder strip to realize the conduction of current. In the back contact cell, the edge PAD point position often does not directly intersect with the main grid line, and the main purpose is to prevent the solder strip from directly contacting the edge position of the cell during the subsequent component welding process (the solder strip needs to be welded at the PAD point position), thereby causing the generation of cell fragments (for example, CN 202210168681.7).

[0003] Therefore, the edge PAD point of the back contact cell often needs to be connected with the edge main grid with the aid of the connection grid line. In order to maximize the extraction of the current at the main line position, the connection grid line at the edge PAD point and the edge main grid position needs to be relatively thick (generally the same width as the main grid), so as to reduce the line resistance of the grid line. However, after thickening, the grid line will face a new problem. If non-corrosive paste (generally main grid and PAD point paste) is used, it will cause the same polarity paste (for example, p-type paste) at the two sides of the connection grid line to be unable to form p-n-p-n cross ohmic contact with the opposite polarity paste (for example, n-type paste) of the connection grid line, thereby causing EL blackening phenomenon. If corrosive paste is used, although p-n-p-n cross ohmic contact can be formed, due to the thickening of the grid line, the gold / half recombination rate at this position is large, and the EL is also black. SUMMARY

[0004] In order to solve the above technical problems, the utility model provides a kind of back contact cell edge connection grid line structure. The surface of the center area of the connection grid line area is printed with a second corrosive paste layer and a second non-corrosive paste layer in sequence. This structure can reduce the line resistance of the entire connection grid line on the one hand, and fully extract the current of the edge main grid. On the other hand, it can also reduce the gold / half recombination caused by corrosive paste.

[0005] The specific technical scheme of the utility model is as follows: a kind of back contact cell edge connection grid line structure, which includes edge main grid area (second doped type semiconductor), two first auxiliary grid areas (first doped type semiconductor), PAD point area (second doped type semiconductor) and connection grid line area. Specifically:

[0006] The edge main grid area and the PAD point area are located on the transverse two sides of the connection grid line area and are connected through the connection grid line area. The two first auxiliary grid areas are symmetrically arranged on the longitudinal two sides of the connection grid line area. The first auxiliary grid area is provided with a gap between the edge main grid area, the PAD point area and the connection grid line area.

[0007] The surface of the central area of the connection grid line area is provided with a transverse second corrosive paste layer; the surface of the non-central area of the connection grid line area, the central area of the edge main grid area and the PAD point area is provided with a non-corrosive paste layer; and the surface of the second corrosive paste layer of the connection grid line area is covered with a second non-corrosive paste layer with a larger area.

[0008] The surface of the first auxiliary grid area is provided with a first corrosive paste layer.

[0009] In the above-mentioned edge connection grid line structure of the back contact battery, the greatest feature is that the surface of the central area of the connection grid line area is successively printed with a second corrosive paste layer and a second non-corrosive paste layer. The structure design can reduce the line resistance of the entire connection grid line, fully draw the edge main grid current, and reduce the gold / half composite caused by the corrosive paste.

[0010] In addition, the design of the above-mentioned second non-corrosive paste layer can fill the gap between the second corrosive paste layer and the non-corrosive paste layer in the connection grid line area, make the entire connection grid line more dense, and the area of the printed second non-corrosive paste layer meeting the above-mentioned size requirement is smaller than that of the non-corrosive paste layer, so that the grid line at the position of the connection grid line can form a "triangular" structure from the cross section, which helps more incident light to enter the battery, and improves the optical performance of the battery.

[0011] Preferably, each of the first auxiliary grid areas extends longitudinally to the connection grid line area to form a longitudinal extension section at one end of the first auxiliary grid area close to the edge main grid area in the transverse direction, and the longitudinal extension section extends transversely to the PAD point area to form a transverse extension section; the longitudinal extension section and the transverse extension section form a hook-shaped pattern; and the longitudinal extension section and the transverse extension section are both provided with a first corrosive paste layer.

[0012] Preferably, in the transverse dimension, the surface of the first corrosive paste layer of the transverse extension section is less than the surface of the second corrosive paste layer of the central area of the connection grid line area, which is less than the distance from one end (i.e. the left side) of the surface of the non-corrosive paste layer of the PAD point area to one end (i.e. the left side) of the surface of the non-corrosive paste layer of the edge main grid area.

[0013] The principle and technical effect of limiting the above transverse size relationship are: firstly, in order to ensure the symmetry of the carrier transmission path, the grid line (i.e. the paste layer) of the first auxiliary grid area and the grid line of the main grid area are required to be kept equal in the transverse length, so that the hole and electron transmission in the silicon body are equal in distance to the respective grid lines, and the corresponding current matching is good. In view of this, the second corrosive paste layer connecting the center area of the grid line area is required to be greater than the first corrosive paste layer of the lateral extension segment on the transverse size, so as to fully ensure that the carrier collection probability of the grid line at the lateral extension segment is not decreased. In addition, in order to make the transverse size of the second corrosive paste layer not too large (if it is too large, the gold / half contact composite area is also large), and at the same time, the subsequent second non-corrosive paste layer is also taken into account, the line resistance of the whole is reduced, so that the transverse size of the second corrosive paste layer connecting the center area of the grid line should be less than or equal to the distance from the end (i.e. the left side) of the lateral extension segment on the surface of the non-corrosive paste layer of the PAD point area to the end (i.e. the left side) of the non-corrosive paste layer on the edge of the main grid area.

[0014] Preferably, in the longitudinal size, the first corrosive paste layer on the surface of the lateral extension segment is less than or equal to the second corrosive paste layer on the surface of the center area of the connecting grid line area, which is less than or equal to the second non-corrosive paste layer on the surface of the connecting grid line area.

[0015] The principle and technical effect of limiting the above transverse size relationship are: firstly, in order to ensure the symmetry of the carrier transmission path, the grid line (i.e. the paste layer) of the first auxiliary grid area and the grid line of the main grid area are required to be kept equal in the transverse length, so that the hole and electron transmission in the silicon body are equal in distance to the respective grid lines, and the corresponding current matching is good. In view of this, the second corrosive paste layer connecting the center area of the grid line area is required to be greater than the first corrosive paste layer of the lateral extension segment on the transverse size, so as to fully ensure that the carrier collection probability of the grid line at the lateral extension segment is not decreased. In addition, in order to make the transverse size of the second corrosive paste layer not too large (if it is too large, the gold / half contact composite area is also large), and at the same time, the subsequent second non-corrosive paste layer is also taken into account, the line resistance of the whole is reduced, so that the transverse size of the second corrosive paste layer connecting the center area of the grid line should be less than or equal to the distance from the end (i.e. the left side) of the lateral extension segment on the surface of the non-corrosive paste layer of the PAD point area to the end (i.e. the left side) of the non-corrosive paste layer on the edge of the main grid area.

[0016] Preferably, in the longitudinal size, the first corrosive paste layer on the surface of the lateral extension segment is less than or equal to the second corrosive paste layer on the surface of the center area of the connecting grid line area, which is less than or equal to the second non-corrosive paste layer on the surface of the connecting grid line area.

[0017] The principle and technical effect of limiting the above transverse / longitudinal size relationship are: on the one hand, the gap between the second corrosive paste layer and the non-corrosive paste layer is filled, so that the whole connection grid line is more dense; on the other hand, the area of the printed second non-corrosive paste layer is small, so that the grid line in the connection grid line area can form a similar "triangular" structure, which helps more incident light to enter the inside of the battery and improves the optical performance of the battery. The transverse size of the second non-corrosive paste layer on the surface of the central area of the connection grid line area is greater than or equal to the second corrosive paste layer in the central area of the connection grid line, but less than or equal to the distance from the end (i.e. the left side) of the transversely extending section on the surface of the non-corrosive paste layer in the PAD point area to the end (i.e. the left side) of the non-corrosive paste layer on the edge main grid area. Similarly, in terms of the longitudinal size of the second non-corrosive paste layer, it should be greater than or equal to the second corrosive paste layer in the central area of the connection grid line, but less than or equal to the non-corrosive paste layer on the surface of the connection grid line area.

[0018] Preferably, the non-corrosive paste layer on the surface of the edge main grid area is divided into two independent and symmetrical parts along the longitudinal direction, and each part is connected to the connection grid line area at one end.

[0019] The utility model discloses a cleverly design independent and symmetrical two parts of the traditional non-corrosive paste layer on the surface of the edge main grid area, which can shorten the carrier transport distance of the edge main grid current gathered to the PAD point and reduce current loss on the one hand, and reduce the amount of paste required for the edge main grid on the other hand, thereby reducing costs.

[0020] Preferably, the area of the edge main grid area, the first auxiliary grid area, the PAD point area and the connection grid line area is greater than the area of the respective surface paste layer.

[0021] Compared with the prior art, the utility model has the beneficial effects that:

[0022] (1) The utility model discloses that the second corrosive paste layer and the second non-corrosive paste layer are printed on the surface of the central area of the connection grid line area. This structure can reduce the line resistance of the whole connection grid line and fully lead out the edge main grid current on the one hand, and can also reduce the gold / half composite caused by corrosive paste on the other hand.

[0023] (2) By further limiting the transverse / longitudinal size of the second corrosive paste layer and the second non-corrosive paste layer on the surface of the connection grid line area, the current matching property can be guaranteed, the carrier collection probability of the first corrosive paste layer of the two transversely extending sections does not decrease, the gold / half composite is avoided from being intensified, and the grid line in the connection grid line area can form a similar "triangular" structure, which helps more incident light to enter the inside of the battery and improves the optical performance of the battery.

[0024] (3) The utility model discloses the corrosionless slurry layer of the surface of the edge main grid area is designed two independent and symmetrical parts, on one hand, the carrier transport distance of the edge main grid current gathering to the PAD point is shortened, and the current loss is less, on the other hand, the slurry consumption of the edge main grid is also less, which helps to reduce the cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a kind of plan view (print second corrosive slurry layer, second corrosionless slurry layer before) of the edge connecting grid line structure of back contact battery of the utility model embodiment 1.

[0026] Figure 2 It is a kind of plan view (print second corrosive slurry layer after, print second corrosionless slurry layer before) of the edge connecting grid line structure of back contact battery of the utility model embodiment 1.

[0027] Figure 3 It is a kind of plan view of the edge connecting grid line structure finished product of back contact battery of the utility model embodiment 1.

[0028] Figure 4 It is Figure 3 It is a kind of local enlarged schematic view and lateral section view of connecting grid line area.

[0029] Figure 5 It is a kind of plan view (print second corrosive slurry layer after, print second corrosionless slurry layer before) of the edge connecting grid line structure of back contact battery of the utility model embodiment 2.

[0030] Figure 6 It is a kind of plan view of the edge connecting grid line structure finished product of back contact battery of the utility model embodiment 2.

[0031] The figure mark is: edge main grid area 1, first auxiliary grid area 2, second auxiliary grid area 3, PAD point area 4, connecting grid line area 5, first corrosive slurry 6, second corrosive slurry 7, corrosionless slurry 8, second corrosionless slurry 9, longitudinal extension section 10, transverse extension section 11;

[0032] A1 is the lateral dimension of the first etching slurry layer on the surface of the lateral extension section, A is the lateral dimension of the second etching slurry layer on the surface of the central region connecting the grid line regions, A2 is the lateral distance from the end of the first etching slurry layer on the surface of the PAD point region to the end of the non-etching slurry layer on the surface of the edge main grid region, B1 is the longitudinal dimension of the first etching slurry layer on the surface of the lateral extension section, B is the longitudinal dimension of the second etching slurry layer on the surface of the connecting grid line region, E is the lateral dimension of the second non-etching slurry layer on the surface of the central region of the connecting grid line region, D is the longitudinal dimension of the second non-etching slurry layer on the surface of the central region of the connecting grid line region, and D1 is the longitudinal dimension of the non-etching slurry layer on the surface of the connecting grid line region. DETAILED DESCRIPTION

[0033] The utility model will be further described below in combination with the embodiments. In the present application, the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal" and the like indicate the orientation or positional relationship shown in the drawings of the specification, which are merely for the convenience of simplifying the description and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore the above terms cannot be understood as limiting the present application.

[0034] OVERALL EMBODIMENT

[0035] A back contact cell edge connection grid line structure includes an edge main grid region (second doped type semiconductor), two first auxiliary grid regions (first doped type semiconductor), a PAD point region (second doped type semiconductor) and a connecting grid line region. Specifically:

[0036] The edge main grid region and the PAD point region are located on the lateral two sides of the connecting grid line region and are connected through the connecting grid line region; the two first auxiliary grid regions are symmetrically arranged on the longitudinal two sides of the connecting grid line region; and a gap is provided between the first auxiliary grid region and the edge main grid region, the PAD point region and the connecting grid line region.

[0037] The central region of the connecting grid line region is provided with a second etching slurry layer in the lateral direction; the non-central region of the connecting grid line region, the edge main grid region and the central region of the PAD point region are provided with a non-etching slurry layer on the surface; and the second etching slurry layer on the surface of the connecting grid line region is covered with a second non-etching slurry layer with a larger area.

[0038] The first auxiliary grid region is provided with a first etching slurry layer on the surface.

[0039] In some specific embodiments, the longitudinal two sides of the PAD point area are also respectively provided with a transverse second auxiliary grid area (second doped type semiconductor), the first auxiliary grid area and the second auxiliary grid area are in an interdigital distribution, and the surface of the second auxiliary grid area is provided with a second corrosive paste layer, and the second corrosive paste layer on the surface of the second auxiliary grid area is respectively connected with the longitudinal two sides of the PAD point area without the corrosive paste layer.

[0040] In some specific embodiments, each of the first auxiliary grid areas extends longitudinally to form a longitudinal extension section near one end of the edge main grid area in the transverse direction to the connecting grid line area, and then extends transversely to form a transverse extension section to the PAD point area; the longitudinal extension section and the transverse extension section constitute a hook-shaped pattern; and the longitudinal extension section and the transverse extension section are both provided with a first corrosive paste layer.

[0041] In some specific embodiments, in the transverse dimension, the transverse dimension of the first corrosive paste layer on the surface of the transverse extension section ≤ the transverse dimension of the second corrosive paste layer on the surface of the central area of the connecting grid line area ≤ the transverse distance from one end (i.e. the left side) of the transverse extension section on the surface of the PAD point area without the corrosive paste layer to one end (i.e. the left side) of the edge main grid area without the corrosive paste layer.

[0042] In some specific embodiments, in the longitudinal dimension, the longitudinal dimension of the first corrosive paste layer on the surface of the transverse extension section ≤ the longitudinal dimension of the second corrosive paste layer on the surface of the central area of the connecting grid line area ≤ the longitudinal dimension of the surface of the connecting grid line area without the corrosive paste layer.

[0043] In some specific embodiments, in the transverse dimension, the transverse dimension of the second corrosive paste layer on the surface of the central area of the connecting grid line area ≤ the transverse dimension of the second non-corrosive paste layer on the surface of the central area of the connecting grid line area ≤ the transverse distance from one end of the transverse extension section on the surface of the PAD point area without the corrosive paste layer to one end of the edge main grid area without the corrosive paste layer. Preferably, in the longitudinal dimension, the longitudinal dimension of the second corrosive paste layer on the surface of the central area of the connecting grid line area ≤ the longitudinal dimension of the second non-corrosive paste layer on the surface of the central area of the connecting grid line area ≤ the longitudinal dimension of the surface of the connecting grid line area without the corrosive paste layer.

[0044] In some specific embodiments, the surface of the edge main grid area without the corrosive paste layer is longitudinally divided into two independent and symmetrical parts, and each part is connected to the connecting grid line area near one end.

[0045] In some specific embodiments, the areas of the edge main grid area, the first auxiliary grid area, the second auxiliary grid area, the PAD point area and the connecting grid line area are greater than the areas of the paste layers on the respective surfaces.

[0046] In some embodiments, the resistivity of the non-corrosive paste layer and the second non-corrosive paste layer in contact with silicon is ≥ 10 mΩ·cm 2 , and the polarity of the non-corrosive paste layer and the second non-corrosive paste layer is the same. The non-corrosive paste comprises: (1) dispersible latex powder or modified resin (as a bonding phase); (2) silver powder without aluminum (or low aluminum content), (3) solvent selected from ethylenediaminetetraacetic acid disodium, stearic acid, etc.

[0047] In some embodiments, the resistivity of the first corrosive paste layer and the second corrosive paste layer in contact with silicon is < 10 mΩ·cm 2 , and the polarity of the first corrosive paste layer and the second corrosive paste layer is opposite. The corrosive paste comprises: (1) strong active glass powder containing lead, bismuth, etc. (as a bonding phase); (2) high aluminum-doped silver powder (aluminum has high activity); (3) solvent selected from terpineol, methyl formate, etc. Specific embodiments

[0049] Example 1

[0050] A back contact cell edge connection gate line structure, which includes an edge main gate area 1 (p region), two first auxiliary gate areas 2 (n region), two second auxiliary gate areas 3 (p region), a PAD point area 4 (p region), and a connection gate line area 5 in the edge area of the back surface of the back contact cell. Among them:

[0051] The edge main gate area and the PAD point area are located on the transverse two sides (i.e. left and right sides in Figures 1-3 ) of the connection gate line area and are connected through the connection gate line area; the two first auxiliary gate areas are symmetrically arranged on the longitudinal two sides (i.e. upper and lower sides in Figures 1-3 ) of the connection gate line area; the transverse second auxiliary gate area is arranged on the longitudinal two sides of the PAD point area, and the first auxiliary gate area and the second auxiliary gate area are distributed in an interdigital manner. A gap (i.e. an isolation area) is provided between the first auxiliary gate area and the edge main gate area, the PAD point area, and the connection gate line area.

[0052] A transverse second corrosive paste layer 7 (p-type polarity) is provided on the surface of the central area of the connection gate line area; a non-corrosive paste layer 8 (p-type polarity) is provided on the surface of the non-central area of the connection gate line area, the edge main gate area, and the central area of the PAD point area; a second non-corrosive paste layer 9 (p-type polarity) with a larger area is covered on the surface of the second corrosive paste layer of the connection gate line area. The second auxiliary gate area is provided with a second corrosive paste layer 7 (p-type polarity) on its surface, and the second corrosive paste layers on the surfaces of the second auxiliary gate areas are respectively connected to the longitudinal two sides of the non-corrosive paste layer of the PAD point area.

[0053] The surface of the first sub-gate area is provided with a first corrosive slurry layer 6 (with n-type polarity). More specifically, each of the first sub-gate areas extends longitudinally towards the connecting gate line area from one end near the edge of the main gate area in the lateral direction to form a longitudinal extension segment 10, and the longitudinal extension segment extends laterally towards the PAD point area to form a lateral extension segment 11; the longitudinal extension segment and the lateral extension segment form a hook-shaped pattern; both the longitudinal extension segment and the lateral extension segment are provided with the first corrosive slurry layer 6 (with n-type polarity).

[0054] In the above structure, the areas of the edge main gate area, the first sub-gate area, the second sub-gate area, the PAD point area, and the connecting gate line area are larger than the area of ​​the slurry layer on their respective surfaces.

[0055] Regarding size:

[0056] In the horizontal direction ( Figure 2 In terms of dimensions (left and right direction), the lateral dimension A1 of the first corrosive slurry layer on the surface of the lateral extension section is equal to the lateral dimension A of the second corrosive slurry layer on the surface of the central area connecting the grid line area, which is less than the distance A2 from one end of the lateral extension section to one end of the edge of the non-corrosive slurry layer on the surface of the PAD point area.

[0057] In the longitudinal direction ( Figure 2 In terms of dimensions (vertical direction), the longitudinal dimension B1 of the first corrosive slurry layer on the surface of the transverse extension section is equal to the longitudinal dimension B of the second corrosive slurry layer on the surface of the central region connecting the gate line area, which is less than the longitudinal dimension D1 of the non-corrosive slurry layer on the surface of the connecting gate line area.

[0058] In the horizontal direction ( Figure 3 In terms of dimensions (left and right direction), the lateral dimension A of the second corrosive slurry layer on the surface of the central area of ​​the connecting gate line region is equal to the lateral dimension E of the second non-corrosive slurry layer on the surface of the central area of ​​the connecting gate line region, which is less than the lateral distance A2 from one end of the non-corrosive slurry layer on the surface of the PAD point area near the lateral extension to one end of the non-corrosive slurry layer on the edge of the main gate area near the edge.

[0059] In the longitudinal direction ( Figure 3 In terms of dimensions (up and down direction), the longitudinal dimension B of the second corrosive slurry layer on the surface of the central region of the connecting gate area is equal to the longitudinal dimension D of the second non-corrosive slurry layer on the surface of the central region of the connecting gate area, which is less than the longitudinal dimension D1 of the non-corrosive slurry layer on the surface of the connecting gate area.

[0060] Under the above size constraints, such as Figure 4 As shown, when viewed from the side, the grid lines (with a non-corrosive slurry layer at the bottom and a second non-corrosive slurry layer at the top) can form a triangular structure, which helps more incident light to enter the battery and improves the battery's optical performance.

[0061] In addition, the resistivity of the non-corrosive paste layer and the second non-corrosive paste layer in contact with silicon is ≥ 10 mΩ·cm 2 The non-corrosive paste uses aluminum-free silver powder as the conductive metal powder, dispersible latex powder as the adhesive phase, and disodium ethylenediaminetetraacetate as the solvent. The resistivity of the first corrosive paste layer and the second corrosive paste layer in contact with silicon is < 10 mΩ·cm 2 The corrosive paste uses aluminum-doped silver powder (aluminum content of 1 wt%) as the conductive metal powder, lead-containing glass powder (lead content of 0.5 wt%) as the adhesive phase, and terpineol as the solvent.

[0062] Example 2

[0063] Example 2 differs from Example 1 only in that the non-corrosive paste layer on the surface of the edge main grid region is divided into two independent and symmetrical parts along the longitudinal direction, and each part is connected to the connection grid line region near one end of the connection grid line region. The specific structure is as follows:

[0064] A back contact cell edge connection grid line structure, which includes an edge main grid region (p region), two first auxiliary grid regions (n region), two second auxiliary grid regions (p region), a PAD point region (p region), and a connection grid line region in the edge region of the back surface of the back contact cell. Among them:

[0065] The edge main grid region and the PAD point region are located on the transverse sides of the connection grid line region and are connected through the connection grid line region; the two first auxiliary grid regions are symmetrically arranged on the longitudinal sides of the connection grid line region; the transverse second auxiliary grid regions are arranged on the longitudinal sides of the PAD point region, and the first auxiliary grid regions and the second auxiliary grid regions are distributed in an interdigital manner. A gap (i.e., an isolation region) is provided between the first auxiliary grid region and the edge main grid region, the PAD point region, and the connection grid line region.

[0066] A transverse second corrosive paste layer (p-type polarity) is provided on the surface of the central region of the connection grid line region; a non-corrosive paste layer (p-type polarity) is provided on the surface of the non-central region of the connection grid line region, the edge main grid region, and the central region of the PAD point region; a second non-corrosive paste layer (p-type polarity) with a larger area is provided on the surface of the second corrosive paste layer of the connection grid line region. The second auxiliary grid region has a second corrosive paste layer (p-type polarity) on its surface, and the second corrosive paste layers on the surfaces of the second auxiliary grid regions are respectively connected to the longitudinal sides of the non-corrosive paste layer of the PAD point region. In addition, as shown in Figure 5 and Figure 6 the non-corrosive paste layer on the surface of the edge main grid region is divided into two independent and symmetrical parts along the longitudinal direction, and each part is connected to the connection grid line region near one end of the connection grid line region.

[0067] The first sub-grid region surface is provided with a first corrosive slurry layer (polarity n type). More specifically, each of the first sub-grid region extends longitudinally to the connecting grid line region to form a longitudinal extension at one end of the edge main grid region close to the edge in the lateral direction, and then extends laterally to the PAD point region to form a lateral extension; the longitudinal extension and the lateral extension form a hook-shaped pattern; the longitudinal extension and the lateral extension are both provided with a first corrosive slurry layer (polarity n type).

[0068] In the above structure, the area of the edge main grid region, the first sub-grid region, the second sub-grid region, the PAD point region and the connecting grid line region is greater than the area of the slurry layer on the respective surface.

[0069] In terms of size:

[0070] In the lateral dimension, the lateral dimension A1 of the first corrosive slurry layer on the surface of the lateral extension = the lateral dimension A of the second corrosive slurry layer on the surface of the central region of the connecting grid line region < the distance A2 from the end of the lateral extension on the surface of the non-corrosive slurry layer on the PAD point region to the end close to the edge on the surface of the non-corrosive slurry layer on the edge main grid region.

[0071] In the longitudinal dimension, the longitudinal dimension B1 of the first corrosive slurry layer on the surface of the lateral extension = the longitudinal dimension B of the second corrosive slurry layer on the surface of the central region of the connecting grid line region < the longitudinal dimension D1 of the non-corrosive slurry layer on the surface of the connecting grid line region.

[0072] In the lateral dimension, the lateral dimension A of the second corrosive slurry layer on the surface of the central region of the connecting grid line region = the lateral dimension E of the second non-corrosive slurry layer on the surface of the central region of the connecting grid line region < the lateral distance A2 from the end of the lateral extension on the surface of the non-corrosive slurry layer on the PAD point region to the end close to the edge on the surface of the non-corrosive slurry layer on the edge main grid region.

[0073] In the longitudinal dimension, the longitudinal dimension B of the second corrosive slurry layer on the surface of the central region of the connecting grid line region = the longitudinal dimension D of the second non-corrosive slurry layer on the surface of the central region of the connecting grid line region < the longitudinal dimension D1 of the non-corrosive slurry layer on the surface of the connecting grid line region.

[0074] Under the above size limitation, the grid line at the connecting grid line position (the bottom is the non-corrosive slurry layer and the top is the second non-corrosive slurry layer) forms a "triangular" structure from the side, which helps more incident light to enter the cell and improves the optical performance of the cell.

[0075] In addition, the resistivity of the non-corrosive slurry layer and the second non-corrosive slurry layer in contact with silicon is ≥ 10 mΩ·cm 2The non-corrosive paste uses aluminum-free silver powder as the conductive metal powder, dispersible latex powder as the adhesive phase, and disodium ethylenediaminetetraacetate as the solvent. 2 The corrosive paste uses aluminum-doped silver powder (aluminum content: 0.5 wt%) as the conductive metal powder, lead-containing glass powder (lead content: 1 wt%) as the adhesive phase, and terpineol as the solvent.

[0076] In the embodiment 2, the traditional non-corrosive paste layer on the surface of the edge main grid region is ingeniously designed into two independent and symmetrical parts, so that the carrier transmission distance of the edge main grid current collected to the PAD point is shortened, the current loss is less, and the paste consumption of the edge main grid is less, which helps to reduce the cost.

[0077] In the utility model, the raw materials and equipment are the common raw materials and equipment in the field, if no special description; the method used in the utility model is the conventional method in the field, if no special description.

[0078] The above is only the preferred embodiment of the utility model, and does not limit the utility model, and any simple modification, change and equivalent transformation according to the technical essence of the utility model to the above embodiment still belong to the protection scope of the utility model technical scheme.

Claims

1. A back contact cell edge termination grid line structure, characterized by: The edge main grid area, two first auxiliary grid areas, a PAD point area and a connecting grid line area are included. The edge main grid area and the PAD point area are located on the transverse two sides of the connecting grid line area and are connected through the connecting grid line area. The surface of the first auxiliary grid area is provided with a first corrosive slurry layer. The surface of the central area of the connecting grid line area is sequentially provided with a transverse second corrosive slurry layer and a second non-corrosive slurry layer with a larger area.

2. The back contact cell edge termination grid line structure of claim 1, wherein: The surface of the non-central area of the connecting grid line area, the edge main grid area and the PAD point area is provided with a non-corrosive slurry layer.

3. The back contact cell edge termination grid line structure of claim 2, wherein: Each of the first auxiliary grid areas extends longitudinally to form a longitudinal extension section near one end of the edge main grid area, and then extends transversely to form a transverse extension section towards the PAD point area.

4. The back contact cell edge termination grid line structure of claim 2 or 3, wherein: In the transverse dimension, the first corrosive slurry layer on the surface of the transverse extension section is less than the second corrosive slurry layer on the surface of the connecting grid line area, which is less than the non-corrosive slurry layer on the surface of the PAD point area from one end of the transverse extension section to one end of the edge main grid area.

5. The back contact cell edge termination grid line structure of claim 3, wherein: In the longitudinal dimension, the first corrosive slurry layer on the surface of the transverse extension section is less than the second corrosive slurry layer on the surface of the connecting grid line area, which is less than the non-corrosive slurry layer on the surface of the connecting grid line area.

6. The back contact cell edge termination grid line structure of claim 5, wherein: In the transverse dimension, the first corrosive slurry layer on the surface of the connecting grid line area is less than the second non-corrosive slurry layer on the surface of the connecting grid line area, which is less than the non-corrosive slurry layer on the surface of the PAD point area from one end of the transverse extension section to one end of the edge main grid area.

7. The back contact cell edge termination grid line structure of claim 1, wherein: In the longitudinal dimension, the second corrosive slurry layer on the surface of the connecting grid line area is less than the second non-corrosive slurry layer on the surface of the connecting grid line area, which is less than the non-corrosive slurry layer on the surface of the connecting grid line area.

8. The back contact cell edge termination grid line structure of claim 1, wherein: The non-corrosive slurry layer on the surface of the edge main grid area is divided into two independent and symmetrical parts along the longitudinal direction, and each part is connected to the connecting grid line area near one end. The areas of the edge main grid area, the first auxiliary grid area, the PAD point area and the connecting grid line area are greater than the areas of the non-corrosive slurry layer, the second non-corrosive slurry layer, the first corrosive slurry layer or the second corrosive slurry layer on their respective surfaces.

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