Back-contact battery cell and battery with stacked-gate structure

Abstract

A back-contact battery cell and battery with a stacked-gate structure. The back-contact battery cell with a stacked-gate structure comprises a battery cell, at least one positive electrode and at least one negative electrode, wherein the positive electrode and the negative electrode are distributed on a back face of the battery cell in a staggered manner; a stacked-gate structure is provided on the positive electrode and the negative electrode; and the stacked-gate structure comprises a current collection layer and electrically conductive wires, the current collection layer being arranged on the positive electrode and the negative electrode, and the electrically conductive wires covering the current collection layer in a stacked manner. There is no gate line on the back face of the battery cell, the stacked-gate structure is closely arranged to replace gate lines to perform current collection and transmission, and the thickness of the current collection layer is reduced; and a photo-generated current on a surface of the battery cell is collected by the current collection layer and is directly transmitted to the electrically conductive wires, thereby eliminating the transmission path of the current on auxiliary gates.

Description

Back contact stacked grid structure cell and battery Technical Field

[0001] The utility model belongs to the technical field of solar cells, in particular to a back-contact stacked-grid structure cell sheet and a battery. Background Art

[0002] The back contact battery transfers the front electrode to the back, with the positive and negative electrodes staggered on the back. There are auxiliary grids on the positive and negative electrodes. All positive auxiliary grids converge on the positive main grid, and all negative auxiliary grids converge on the negative main grid. The main grid and auxiliary grids are perpendicular, and the number of main grids is generally 2 to 20.

[0003] The gate wire material is mainly silver, accounting for about half of the non-silicon cost of the battery. The gate wire plays the role of collecting and transmitting current. In particular, the lateral current transmission path requires the smallest possible resistance. Therefore, the cross-sectional area of ​​the gate wire must be increased accordingly, and the corresponding silver consumption will increase significantly, resulting in high battery costs.

[0004] Since the back-contact battery transfers the front electrode to the back, the back shading increases significantly, so the battery bifaciality drops significantly. Currently, the bifaciality of the back-contact battery is about 50%, which is much lower than the 80% of the conventional double-sided electrode structure battery. Summary of the Invention

[0005] The purpose of the utility model is to provide a back-contact stacked grid structure cell and battery to solve the above-mentioned problems existing in the prior art.

[0006] Technical solution: A back-contact stacked-grid structure cell, comprising a cell, at least one positive electrode, and at least one negative electrode, wherein the positive electrode and the negative electrode are alternately distributed on the back of the cell;

[0007] A stacked grid structure is provided on the positive electrode and the negative electrode. The stacked grid structure includes a current collecting layer and a conductive wire. The current collecting layer is provided on the positive electrode and the negative electrode, and the conductive wire is superimposed and covered on the current collecting layer.

[0008] Preferably, the current collecting layer is a continuous or segmented grid line structure.

[0009] Preferably, the current collection layer has a width of 0.01 mm to 0.1 mm, a height of 1 μm to 20 μm, and a spacing of 0.5 mm to 2 mm.

[0010] Preferably, the width of the positive electrode and the negative electrode is 0.2 mm to 1 mm.

[0011] Preferably, the cross-sectional shape of the conductive wire is a plane geometric shape.

[0012] Preferably, a conductive connecting material is provided between the current collecting layer and the conductive filament.

[0013] Preferably, it further comprises a conductive connecting strip, wherein the conductive connecting strip is arranged on the back of the battery cell;

[0014] The conductive connecting strip connects the conductive threads connected to the same electrode in series and separates them from the conductive threads connected to another electrode by an insulating material.

[0015] The utility model also provides a back-contact stacked grid structure battery, comprising at least two battery cells as described above, wherein the positive electrodes and negative electrodes of two adjacent battery cells are connected by a conductive wire.

[0016] Preferably, a second conductive connecting bar is provided in the interval between two adjacent battery cells, and the second conductive connecting bar connects the conductive wires connected to the same electrode in series. Beneficial effects

[0017] In summary, the beneficial effects of the present invention are:

[0018] 1. There is no grid line on the back of the battery cell. The grid line is used to collect and transmit current through the dense stacked grid structure, and the thickness of the current collection layer is thinned, which greatly reduces silver consumption and reduces battery costs.

[0019] 2. The photogenerated current on the surface of the cell is collected by the current collection layer and directly transmitted to the conductive filament, eliminating the current transmission path on the secondary grid. The current transmission path is short, the resistance loss is low, and the battery efficiency is high.

[0020] 3. The cross-section of the conductive wire is a plane geometric shape with high reflectivity. It can reflect the light projected onto the conductive wire to the surface of the battery cell for use, reducing the actual shading on the back and improving the battery bifaciality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a schematic diagram of a back-contact stacked-grid structure cell provided by the present invention;

[0022] FIG2 is a back view of a back-contact stacked-grid structure cell provided by the present invention;

[0023] FIG3 is a schematic diagram of a back-contact stacked-grid structure battery provided by the present invention.

[0024] The figures are marked as follows: 1. battery cell; 2. current collecting layer; 3. conductive wire; 4. conductive connecting material; 5. first conductive connecting strip; 6. insulating material; 7. second conductive connecting strip. Modes for Carrying Out the Invention

[0025] DETAILED DESCRIPTION

[0026] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features known in the art are not described to avoid confusion with the present invention. Example 1

[0027] As shown in Figure 1, the back-contact stacked grid structure cell disclosed in this embodiment includes a cell 1, at least one positive electrode, and at least one negative electrode. The positive electrode and the negative electrode are alternately distributed on the back of the cell 1. A stacked grid structure is provided on the positive electrode and the negative electrode. The stacked grid structure includes a current collection layer 2 and a conductive wire 3. The current collection layer 2 is arranged on the positive electrode and the negative electrode, and the conductive wire 3 is superimposed and covered on the current collection layer 2. There is no grid line on the back of the cell 1. The grid line is abolished for current collection and transmission by the densely arranged stacked grid structure, and the thickness of the current collection layer 2 is thinned, which greatly reduces silver consumption and reduces battery cost. The photogenerated current on the surface of the cell 1 is collected by the current collection layer 2 and directly transmitted to the conductive wire 3, eliminating the current transmission path on the secondary grid. The current transmission path is short, the resistance loss is low, and the battery efficiency is high.

[0028] As shown in FIG1 , the current collection layer 2 is a continuous or segmented grid line structure. Both structures can realize current collection and transmission. When the current collection layer 2 adopts a segmented grid line structure, the silver consumption can be further reduced.

[0029] As shown in FIG1 , the current collecting layer 2 has a width of 0.01 mm to 0.1 mm, a height of 1 μm to 20 μm, and a spacing of 0.5 mm to 2 mm.

[0030] As shown in Figure 1, the width of the positive electrode and the negative electrode is 0.2mm~1mm.

[0031] As shown in Figure 1, the cross-sectional shape of the conductive wire 3 is a plane geometric shape. The cross-sectional shape of the conductive wire 3 can be a triangle, a circle, a semicircle, or a trapezoid. The cross-sectional shape of the conductive wire 3 is a plane geometric shape with high reflectivity. It can reflect the light projected onto the conductive wire 3 to the surface of the battery cell 1 for use, thereby reducing the actual shading on the back side and improving the battery bifaciality.

[0032] As shown in FIG1 , a conductive connecting material 4 is provided between the current collecting layer 2 and the conductive wire 3 to improve the stability of the connection between the current collecting layer 2 and the conductive wire 3 . Example 2

[0033] As shown in Figure 2, the difference from Example 1 is that the back-contact stacked grid structure cell disclosed in this embodiment also includes a first conductive connecting strip 5. The first conductive connecting strip 5 is arranged on the back of the cell 1. The first conductive connecting strip 5 connects the conductive wires 3 connected to the same electrode in series and is separated from the conductive wire 3 connected to the other electrode by an insulating material 6.

[0034] This is because each positive or negative electrode area is independent of each other, and the current on each conductive wire 3 is also independent of each other. There are certain differences in the photoelectric conversion capacity of each area in the battery cell 1, resulting in certain differences in the current between the conductive wires 3 and the inability to flow between them to achieve balance. When the battery cells 1 are connected in series, the current mismatch loss between the battery cells 1 will be greatly increased, thereby reducing the power generation efficiency of the battery cell 1.

[0035] Therefore, in this embodiment, the conductive wires 3 connected to the same electrode are connected in series through the first conductive connecting bar 5, so as to realize the free flow of current between the conductive wires 3, make the current on each conductive wire 3 consistent, reduce the current mismatch loss between the battery cells 1, and improve the power generation efficiency of the battery cell 1. At the same time, the first conductive connecting bar 5 is separated from the conductive wire 3 connected to the other electrode by the insulating material 6 to prevent short circuit. Example 3

[0036] As shown in FIG3 , the back-contact stacked-grid structure battery disclosed in this embodiment includes at least two battery cells 1 in Example 1, and the positive and negative electrodes of two adjacent battery cells 1 are connected by a conductive wire 3 .

[0037] As shown in FIG3 , a second conductive connecting bar 7 is provided in the interval between two adjacent battery cells 1 , and the second conductive connecting bar 7 connects the conductive wires 3 connected to the same electrode in series.

[0038] The second conductive connecting strip 7 in this embodiment plays the same role as the first conductive connecting strip 5 in the second embodiment.

[0039] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the scope of protection of the present invention.

Claims

1. A back-contact overlapping gate structure solar cell, characterized in that, It includes a solar cell (1), at least one positive electrode, and at least one negative electrode, and the positive and negative electrodes are staggered and distributed on the back of the solar cell (1). A stacked grid structure is provided on the positive and negative electrodes. The stacked grid structure includes a current collection layer (2) and conductive wires (3). The current collection layer (2) is provided on the positive and negative electrodes, and the conductive wires (3) are stacked and covered on the current collection layer (2).

2. The back-contact overlapping gate structure solar cell according to claim 1, wherein The current collection layer (2) is a continuous or segmented grid line structure.

3. The back-contact overlapping gate structure solar cell according to claim 1, wherein The width of the current collection layer (2) is 0.01 mm to 0.1 mm, the height is 1 μm to 20 μm, and the spacing is 0.5 mm to 2 mm.

4. The back-contact overlapping gate structure solar cell according to claim 1, wherein The width of the positive and negative electrodes is 0.2 mm to 1 mm.

5. The back-contact stacked gate structure solar cell according to claim 1, characterized in that, The cross-sectional shape of the conductive wire (3) is a planar geometric shape.

6. The back-contact overlapping gate structure solar cell according to claim 1, wherein A conductive connection material (4) is provided between the current collection layer (2) and the conductive wire (3).

7. The back-contact overlapping gate structure solar cell according to claim 1, wherein It further includes a first conductive connection bar (5), and the first conductive connection bar (5) is provided on the back of the solar cell (1). The first conductive connection bar (5) serially connects the conductive wires (3) connected to the same electrode and separates them from the conductive wires (3) connected to the other electrode by an insulating material (6).

8. A back-contact overlapping gate structure battery, characterized in that, It includes at least two solar cells (1) as described in any one of claims 1 to 7, and the positive and negative electrodes of adjacent two solar cells (1) are connected by conductive wires (3).

9. The back-contact stacked gate structure battery according to claim 8, wherein A second conductive connection bar (7) is provided in the spacing between adjacent two solar cells (1), and the second conductive connection bar (7) serially connects the conductive wires (3) connected to the same electrode.

Images