Photovoltaic module battery pack, welding process and packaging glass structure

Abstract

The present invention discloses a photovoltaic module battery group, a welding process and a packaging glass structure, wherein the photovoltaic module battery group includes several columns of battery cells, each column of battery cells includes a plurality of battery cells arranged in a stepped shape from low to high, and the battery cells are provided with a front main grid and a back electrode, and the front main grid and the back electrode are both connected with welding strips and the welding strips are all in a flat state, and two adjacent battery cells are displaced by a height difference to achieve a zero distance effect in the horizontal direction, thereby reducing the non-power generation area in the photovoltaic cell and improving the power generation efficiency per unit area of ​​the photovoltaic cell. The present invention also provides a welding process for the above-mentioned photovoltaic module battery group and a packaging glass structure for installing the photovoltaic module battery group. When the photovoltaic module battery group is welded, the welding strip does not bend, and the battery cell will not be squeezed, thereby avoiding the problem of hidden cracks in the battery cell. The packaging glass structure achieves a zero spacing arrangement between two adjacent columns of battery cells through the height difference of each group of stepped glass platforms.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cell modules, and in particular to a photovoltaic module battery group, a welding process and a packaging glass structure. Background Art

[0002] Conventional photovoltaic modules on the market today, whether traditional PERC or the current mainstream TOPCon and HJT double-glass modules, all use an assembly structure of front glass, film, battery pack, film, and back glass. Among them, the battery pack needs to use interconnection strips to weld the main grids on the front and back of each battery cell, so that all the battery cells are connected in series or parallel to form a battery pack.

[0003] Regarding the welding of battery cells in series, the mainstream method on the market is "Z" type welding, such as Figure 1 As shown, on a flat welding table A, the battery cell C is connected through sections of welding ribbon B. In order to connect the positive and negative electrodes of two batteries, the welding ribbon needs to pass from the front of one battery to the back of the other battery. Therefore, the middle of the welding ribbon needs to be bent and flattened, and the entire welding ribbon presents a "Z" shape. Although the technology is still being improved, its two core problems have never been solved. Problem 1: The welding ribbon exists in a Z shape between the two battery cells. No matter how the diameter of the welding ribbon is reduced, the gap between the two battery cells is still 0.8-2.0mm. Problem 2: In addition to the gap, the welding ribbon is made of hard metal, while the battery cell is made of fragile silicon. When the folded welding ribbon extends from the upper surface edge of one battery to the back surface of another battery, the edges of the two batteries are easily squeezed by the welding ribbon, causing the battery cell "eight" hidden crack problem. Summary of the invention

[0004] Purpose of the invention: In view of the above shortcomings, the present invention provides a photovoltaic module battery group, welding process and packaging glass structure, which can remove the gap between battery cells, achieve micro gaps or even zero gaps, and solve the problem of hidden cracks on the edges of battery cells.

[0005] Technical solution: To solve the above problems, the present invention adopts a photovoltaic module battery group, including several columns of battery cells, each column of battery cells includes a first battery cell, a second battery cell, ... an Nth battery cell arranged in a stepped manner from low to high, and a front main grid and a back electrode are provided on the battery cell, and the front main grid and the back electrode are connected with welding strips and the welding strips are all in a flat state; the front main grid of the n-1th battery cell is connected to the back electrode of the nth battery cell through the same welding strip, N≥n≥2; the projection of an edge of one end of the nth battery cell close to the n-1th battery cell on the n-1th battery cell intersects with the edge of the n-1th battery cell close to the nth battery cell.

[0006] Furthermore, the battery cells are divided into two groups, each group of battery cells includes a first column of battery cells, ... Mth column of battery cells, the N'th battery cell in the first column of battery cells, the N'th battery cell in the second column of battery cells, ... the N'th battery cell in the Mth column of battery cells are arranged in a stepped manner from low to high; the edge of one end of the N'th battery cell in the mth column of battery cells close to the N'th battery cell in the m-1th column of battery cells is projected on the m-1th column of battery cells and the edge of the N'th battery cell on the m-1th column of battery cells close to the N'th battery cell in the m-1th column of battery cells intersects; wherein, M≥m≥2, N' is (1, ..., N); the battery cells in the first column of the two groups of battery cells are located at the same height, and the battery cells in the mth column of the two groups of battery cells are located at the same height; and there is a gap between the battery cells in the first column of the two groups of battery cells.

[0007] Furthermore, a first welding strip is connected to the back electrode of the first battery cell, an N+1 welding strip is connected to the positive main grid of the Nth battery cell, and one end of the first welding strip and the N+1 welding strip is connected to a bus bar.

[0008] The present invention also provides a welding process for making the above photovoltaic module battery group, providing a welding platform, the welding platform is in a stepped shape, including a first platform, a second platform, ..., an N-1th platform, and an Nth platform arranged in sequence from low to high, the upper surfaces of each platform are parallel to each other, and the connecting surface between the upper surfaces of each platform is perpendicular to the upper surface of each platform, wherein the width of the second platform, ..., and the N-1th platform is equal to the width of the battery cell placed on the platform, and the welding process comprises the following steps:

[0009] Step 1, cutting a plurality of first welding strips;

[0010] Step 2, laying a plurality of first welding strips in parallel on the first platform;

[0011] Step 3, laying the first battery cell on the first welding strip, with one side of the first battery cell against the connection surface, and the back electrode of the first battery cell pressed on the first welding strip;

[0012] Step 4, cutting a number of second welding strips;

[0013] Step 5, laying a plurality of second welding strips in parallel on the positive main grid of the first battery cell and the second platform;

[0014] Step 6: Use welding tools to press and fix the first battery cell, the first welding ribbon, and the second welding ribbon;

[0015] Step 7, laying the second battery cell on the second welding strip on the second platform, with one side of the second battery cell against the connection surface, and the back electrode of the second battery cell pressed on the second welding strip;

[0016] Step 8, cutting a number of third welding strips;

[0017] Step 9, laying a plurality of third welding strips in parallel on the positive main grid of the second battery cell and the third platform;

[0018] Step 10: Use welding tools to press and fix the second battery cell, the second welding ribbon, and the third welding ribbon;

[0019] Step 11, repeat steps 7-10 until the Nth battery sheet is laid and fixed;

[0020] Step 12: welding the photovoltaic module battery group obtained in step 11 at a preset welding temperature.

[0021] Furthermore, the number of welding strips connected to the front of each battery cell is equal to the number of positive main grids of the battery cell, the number of welding strips connected to the back of each battery cell is equal to the number of back electrodes of the battery cell, and the number of back electrodes of each battery cell is equal to the number of positive main grids of the battery cell.

[0022] Furthermore, when laying the welding strips, each welding strip is entirely on the same plane without bending.

[0023] Furthermore, an N+1th welding strip is laid in the positive main grid of the Nth battery cell, the length of the N+1th welding strip is equal to the length of the first welding strip, the length of the second welding strip is equal to the length of the third welding strip, and the length of the first welding strip is less than the second welding strip and the third welding strip.

[0024] The present invention also provides a packaging glass structure for installing the above-mentioned photovoltaic module battery group, comprising front glass and back glass, wherein the upper end surface of the back glass is provided with a plurality of stepped glass platforms; the stepped glass platforms are used to install the photovoltaic module battery group, each group of stepped glass platforms is provided with a plurality of battery installation platforms distributed in a step manner and a busbar installation platform connected to the highest battery installation platform, a battery cell is installed on each battery installation platform, and there is a height difference between two adjacent groups of stepped glass platforms; when the photovoltaic module battery group is installed on the stepped glass platform, the photovoltaic module battery group is fitted with the upper surface of the stepped glass platform, and the projections of the two adjacent groups of photovoltaic battery groups in the horizontal direction intersect in a straight line; the shape of the lower end surface of the front glass matches the stepped glass platform.

[0025] Furthermore, the plurality of groups of stepped glass platforms are symmetrically distributed, the heights of the stepped glass platforms gradually decrease from the outside to the inside, and the heights of the two groups of stepped glass platforms close to both sides of the symmetry axis are equal.

[0026] Furthermore, the thickness of the front glass and the back glass at the thickest part is H, 2.5mm≥H≥3.5mm, and the thickness of the front glass and the back glass at the thinnest part is h, h≥0.5mm.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) the photovoltaic module battery group achieves the effect of zero horizontal distance between battery cells through a stepped arrangement of battery cells, thereby reducing the non-power generation area in the photovoltaic cell and improving the power generation efficiency per unit area of ​​the photovoltaic cell; (2) when the photovoltaic module battery group is welded, the welding ribbon will not bend and will not squeeze the battery cell, thus avoiding the problem of hidden cracks in the battery cell; (3) a packaging glass structure for installing the photovoltaic module battery group is also designed, and the zero spacing arrangement between two adjacent columns of battery cells is achieved through the height difference of each group of stepped glass platforms, thereby further reducing the non-power generation area in the photovoltaic cell and improving the power generation efficiency per unit area of ​​the photovoltaic cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the existing 'Z'-shaped welding;

[0029] Figure 2 It is a schematic diagram of the structure of the welding platform and photovoltaic module battery group of the present invention;

[0030] Figure 3 A top view of the encapsulated glass structure of the present invention;

[0031] Figure 4 It is a side view of the packaged glass structure of the present invention after being disassembled;

[0032] Figure 5 It is a schematic diagram of the partial structure of the back glass of the present invention;

[0033] Figure 6 It is a schematic diagram of the structure of the photovoltaic module battery group of the present invention installed on the back glass. DETAILED DESCRIPTION

[0034] like Figure 2 As shown, a photovoltaic module battery group and its welding process in this embodiment, the welding process needs to use a welding platform that is overall stepped, including a first platform 1, a second platform 2...a sixth platform arranged in order from low to high, and the number of platforms can be determined according to the number of cells set in the photovoltaic cell, and the number of platforms N is generally 8-15. In this embodiment, the width of the second platform to the fifth platform is equal to the width of the cell, and the width of the first and sixth platforms is greater than the width of the cell. Figure 2 To avoid duplication, the structure is simplified into three platforms, omitting several platforms with the same width in the middle. The upper surfaces of each platform are parallel to each other, and the connecting surface 4 between the upper surfaces of each platform is perpendicular to the upper surfaces of each platform. The height difference between two adjacent platforms is equal, and the height difference is adjusted according to the thickness of the battery cell and the thickness of the welding strip, generally 200-300μm, and the width of each platform is adjusted according to the width of the battery cell, generally 182-210mm.

[0035] The welding process using the above welding platform specifically includes the following steps:

[0036] Step 1: Use a robot to intercept a number of first welding ribbons 5. The number of first welding ribbons 5 is equal to the number of back electrodes on the first battery cell. In this embodiment, the number of back electrodes on each battery cell is 10.

[0037] Step 2: Lay a plurality of first welding tapes 5 on the first platform, wherein the laying positions of the first welding tapes 5 correspond to the positions of the back electrodes of the first battery cells 6 .

[0038] Step 3, laying the first battery cell 6 on the first welding ribbon 5 , with one side of the first battery cell 6 against the connecting surface 4 of the first platform 1 and the second platform 2 , and the back electrode of the first battery cell 6 pressed against the first welding ribbon 5 .

[0039] Step 4: Use a robot to intercept several second welding ribbons 7. The number of second welding ribbons 7 is equal to the number of positive main grids 61 of the first battery cell, and is also equal to the number of back electrodes of the second battery cell. The length of the second welding ribbon 7 can cover the positive main grid of the first battery cell and the back electrode of the second battery cell.

[0040] Step 5: Lay a plurality of second welding strips 7 on the positive main grid 61 of the first battery cell and the second platform 2. A second welding strip 7 is laid on the positive main grid of each battery cell. Due to the stepped design of the welding platform, the height difference between the platforms is adjusted according to the thickness of the battery cell and the welding strip, so that the part of the second welding strip laid on the first battery cell and the part laid on the second platform 2 are on the same plane without bending.

[0041] Step 6: Use welding tools to press and fix the first battery cell, the first welding ribbon, and the second welding ribbon.

[0042] Step 7, lay the second battery cell 8 on the second welding ribbon 7 located on the second platform 2, with one side of the second battery cell 8 against the connecting surface 4 between the third platform and the second platform, and the back electrode of the second battery cell 8 pressed on the second welding ribbon 7.

[0043] Step 8: using a robot to intercept a number of third welding strips 9.

[0044] Step 9: Lay a plurality of third welding strips 9 on the positive main grid of the second battery cell 8 and the third platform 3 .

[0045] Step 10: Use welding tools to press and fix the second battery cell 8, the second welding ribbon 7 and the third welding ribbon 9.

[0046] Step 11: Repeat steps 7-10 until the sixth battery cell is laid and fixed.

[0047] Step 12: weld the row of cells obtained in step 11 at a preset welding temperature. A conveyor belt is provided on the welding platform, and the conveyor belt is horizontally driven to move the row of cells obtained in step 11 to the infrared heating lamp, and irradiate at the preset welding temperature for several seconds to complete the welding of the row of cells. Repeat the above steps to complete the welding of twelve rows of cells.

[0048] In the above welding process, a seventh welding strip is laid on the sixth battery cell positive electrode main grid, and the length of the seventh welding strip is equal to that of the first welding strip. The first welding strip and the seventh welding strip are only connected to one battery cell, and the side not connected to the battery cell is used to connect the bus bar 10. The second welding strip, the third welding strip ... the sixth welding strip are all connected to two battery cells, and their lengths are equal, and the length of the first welding strip is less than that of the second welding strip and the third welding strip.

[0049] The horizontal projections of adjacent cells in a row of cells produced by the above welding process intersect in a straight line, and the welding strips are all flat and not bent. The cells are staggered by height difference, eliminating the horizontal spacing of the cells, achieving the effect of zero spacing between the two cells, reducing the non-power generation area of ​​the photovoltaic cell, and improving the power generation efficiency.

[0050] like Figures 3 to 6 As shown, in order to install the photovoltaic module battery group processed by the above welding process, a packaging glass structure with a special shape is required, including front glass 11 and back glass 12. The shape of the lower end surface of the front glass 11 matches the shape of the upper end surface of the back glass 12, and the battery cell is installed between the front glass 11 and the back glass 12. The thickness of the thickest part of the front glass 11 and the back glass 12 is H, 2.5mm≥H≥3.5mm, and the thickness of the thinnest part of the front glass 11 and the back glass 12 is h, h≥0.5mm. Twelve groups of stepped glass platforms 13 are provided on the upper end surface of the back glass 12, and each group of stepped glass platforms 13 is provided with six stepped battery installation platforms 131, and each battery installation platform 131 is installed with a battery cell. A busbar installation platform 132 is provided on one side of the highest battery installation platform, and the busbar installation platform 132 and the battery installation platform are also stepped, and the height difference is equal to the height difference of each battery installation platform. The battery installation platform with the lowest height is relatively wide. One of the busbars on both sides of the photovoltaic module battery group is installed on the busbar installation platform 132, and the other is installed on the battery installation platform with the lowest height. The size and number of the stepped glass platform 13 are adjusted according to the specific situation of the photovoltaic module battery group. Except for the battery installation platform with the lowest height, the size of each battery installation platform in the middle is consistent with the size of the battery cell. The photovoltaic module battery group that has been welded is installed on the stepped glass platform. When the photovoltaic module battery group is installed on the stepped glass platform, the photovoltaic module battery group fits with the upper surface of the stepped glass platform.

[0051] The twelve groups of stepped glass platforms 13 are symmetrically arranged, six groups each on the upper and lower sides, and the height of each group of stepped glass platforms gradually decreases from the outside to the inside, and the heights of the two groups of stepped glass platforms close to the two sides of the symmetry axis are equal. When the photovoltaic module battery group is installed on the stepped glass platform, the battery cells are divided into two groups, each group of battery cells includes the first column of battery cells, ... the sixth column of battery cells, the N'th battery cell in the first column of battery cells, the N'th battery cell in the second column of battery cells, ... the N'th battery cell in the sixth column of battery cells are arranged in a stepped manner from low to high; the N'th battery cell in the mth column of battery cells is close to the N'th battery cell in the m-1th column. The projection of the N'th battery cell on the m-1th column of battery cells intersects with the edge of the N'th battery cell on the m-1th column of battery cells close to the N'th battery cell in the mth column of battery cells; wherein, 6≥m≥2, N' is (1, ..., 6). The two groups of battery cells are symmetrically arranged, and there is a gap between the first column of battery cells in the two groups of battery cells. The two first-row cells at the same height need to be spaced a certain distance apart to avoid short circuits caused by contact between the two photovoltaic module cell groups. The height differences of the other columns of cells are set to avoid short circuits caused by contact between two adjacent columns of cells. There is no need to consider the horizontal spacing. The horizontal projections of two adjacent columns of cells intersect in a straight line, achieving the effect of zero spacing between two adjacent columns of cells.

[0052] The present invention achieves the effect of zero spacing between the horizontal distances between the cells by arranging the cells in a stepped manner, thereby reducing the non-power generation area in the photovoltaic cell and improving the power generation efficiency per unit area of ​​the photovoltaic cell. At the same time, when welding the photovoltaic module battery group, the welding ribbon does not bend, nor does it squeeze the cells, thereby avoiding the problem of hidden cracks in the cell. The present invention also designs a packaging glass structure for installing the photovoltaic module battery group, and realizes the zero spacing arrangement between two adjacent columns of cells by the height difference of each group of stepped glass platforms, further reducing the non-power generation area in the photovoltaic cell and improving the power generation efficiency per unit area of ​​the photovoltaic cell.

Claims

1. A photovoltaic module battery pack, characterized in that: The invention comprises a plurality of columns of battery cells, each column of battery cells comprises a first battery cell, a second battery cell, ... an Nth battery cell arranged in order from low to high in a ladder shape, a front main grid and a back electrode are provided on the battery cell, and the front main grid and the back electrode are both connected with welding strips and the welding strips are all in a flat state; the front main grid of the n-1th battery cell is connected to the back electrode of the nth battery cell through the same welding strip, N≥n≥2; the projection of an edge of the nth battery cell close to the n-1th battery cell on the n-1th battery cell intersects with the edge of the n-1th battery cell close to the nth battery cell; The battery cells are divided into two groups, each group of battery cells includes battery cells in the first column, ... battery cells in the Mth column, the N'th battery cell in the first column, the N'th battery cell in the second column, ... the N'th battery cell in the Mth column are arranged in a stepped manner from low to high; the edge of one end of the N'th battery cell in the mth column close to the N'th battery cell in the m-1th column is projected on the m-1th column and the edge of the N'th battery cell on the m-1th column close to the N'th battery cell in the m-1th column intersects; wherein, M≥m≥2, N' is (1, ..., N); the battery cells in the first column of the two groups of battery cells are located at the same height, and the battery cells in the mth column of the two groups of battery cells are located at the same height; and there is a gap between the battery cells in the first column of the two groups of battery cells.

2. The photovoltaic module battery pack according to claim 1, characterized in that: A first welding strip is connected to the back electrode of the first battery cell, an N+1 welding strip is connected to the positive main grid of the Nth battery cell, and one end of the first welding strip and the N+1 welding strip is connected to a bus bar.

3. A welding process for manufacturing a photovoltaic module battery group according to any one of claims 1-2, characterized in that: A welding platform is provided, wherein the welding platform is in a stepped shape, including a first platform, a second platform, ..., an N-1th platform, and an Nth platform arranged in order from low to high, the upper surfaces of the platforms are parallel to each other, and the connecting surfaces between the upper surfaces of the platforms are perpendicular to the upper surfaces of the platforms, wherein the widths of the second platform, ..., and the N-1th platform are equal to the widths of the battery cells placed on the platforms, and the welding process comprises the following steps: Step 1, cutting a plurality of first welding strips; Step 2, laying a plurality of first welding strips in parallel on the first platform; Step 3, laying the first battery cell on the first welding strip, with one side of the first battery cell against the connection surface, and the back electrode of the first battery cell pressed on the first welding strip; Step 4, cutting a number of second welding strips; Step 5, laying a plurality of second welding strips in parallel on the positive main grid of the first battery cell and the second platform; Step 6: Use welding tools to press and fix the first battery cell, the first welding ribbon, and the second welding ribbon; Step 7, laying the second battery cell on the second welding strip on the second platform, with one side of the second battery cell against the connection surface, and the back electrode of the second battery cell pressed on the second welding strip; Step 8, cutting a number of third welding strips; Step 9, laying a plurality of third welding strips in parallel on the positive main grid of the second battery cell and the third platform; Step 10: Use welding tools to press and fix the second battery cell, the second welding ribbon, and the third welding ribbon; Step 11, repeat steps 7-10 until the Nth battery sheet is laid and fixed; Step 12: welding the photovoltaic module battery group obtained in step 11 at a preset welding temperature.

4. The welding process according to claim 3, characterized in that: The number of welding strips connected to the front of each battery cell is equal to the number of positive main grids of the battery cell, the number of welding strips connected to the back of each battery cell is equal to the number of back electrodes of the battery cell, and the number of back electrodes of each battery cell is equal to the number of positive main grids of the battery cell.

5. The welding process according to claim 4, characterized in that: When laying the welding tape, each welding tape is in the same plane as a whole without bending.

6. The welding process according to claim 5, characterized in that: The N+1th welding strip is laid in the positive main grid of the Nth battery cell, the length of the N+1th welding strip is equal to the length of the first welding strip, the length of the second welding strip is equal to the length of the third welding strip, and the length of the first welding strip is less than the second welding strip and the third welding strip.

7. A packaging glass structure for installing the photovoltaic module battery group according to any one of claims 1-2, characterized in that: It comprises front glass and back glass, wherein the upper end face of the back glass is provided with a plurality of stepped glass platforms; the stepped glass platforms are used to install photovoltaic module battery groups, each group of stepped glass platforms is provided with a plurality of battery installation platforms distributed in a step manner and a busbar installation platform connected to the highest battery installation platform, a battery cell is installed on each battery installation platform, and there is a height difference between two adjacent groups of stepped glass platforms; when the photovoltaic module battery group is installed on the stepped glass platform, the photovoltaic module battery group fits with the upper surface of the stepped glass platform, and the projections of the two adjacent groups of photovoltaic battery groups in the horizontal direction intersect in a straight line; the shape of the lower end face of the front glass matches the stepped glass platform.

8. The encapsulated glass structure according to claim 7, wherein: The plurality of groups of stepped glass platforms are symmetrically distributed, and the heights of the stepped glass platforms gradually decrease from the outside to the inside. The heights of the two groups of stepped glass platforms close to the two sides of the symmetry axis are equal.

9. The encapsulated glass structure according to claim 8, characterized in that: The thickness of the front glass and the back glass at the thickest part is H, 2.5mm≥H≥3.5mm, and the thickness of the front glass and the back glass at the thinnest part is h, h≥0.5mm.

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