Main-grid-free back contact battery

Abstract

The invention discloses a main-grid-free back contact battery which is formed by connecting a plurality of battery assemblies in series, each battery assembly comprises a plurality of first auxiliary grid groups, a plurality of second auxiliary grid groups, at least one first welding strip and at least one second welding strip, the first welding strips are connected with the first auxiliary grid groups and are insulated from the second auxiliary grid groups, and the second welding strips are connected with the second auxiliary grid groups. The first welding strips and the second welding strips of two adjacent battery assemblies are connected, all the first welding strips of the battery assembly at one end are connected to serve as the positive electrode of the main-grid-free back contact battery, and all the second welding strips of the battery assembly at the other end serve as the negative electrode of the main-grid-free back contact battery. And all the second welding strips of the battery assembly at the other end are connected to serve as the negative electrode of the main-grid-free back contact battery. The main-grid-free back contact battery is free of the main grid, the silver consumption of the battery is reduced, the battery cost is reduced, and the problem that in the prior art, due to the fact that the main grid is arranged, an auxiliary grid opposite to the auxiliary grid in polarity needs to be subjected to insulation treatment near the main grid, and short circuit may occur due to poor treatment is effectively solved.

Description

Technical Field

[0001] The invention relates to a main grid-free back contact battery, belonging to the field of solar cells. Background Art

[0002] With the development of high-efficiency battery technology, there is an urgent need to reduce costs and increase efficiency. In the production cost of crystalline silicon batteries, silicon materials account for about 60-70% of the material cost, and the amount of silver paste accounts for about 20-30% of the material cost. The back-contact battery electrodes are all distributed on the back, with the main grid and the auxiliary grid positive and negative poles arranged in a staggered manner. Although the front grid line has been cancelled, the back also faces the problem of high consumption of electrode silver paste and high cost.

[0003] The back-contact cell is a cell in which both the PN junction and the metal contact are located on the back of the solar cell. The front of the cell uses a double-layer SiNx / SiOx anti-reflection passivation film, without any metal electrode obstruction, which maximizes the use of incident light and improves conversion efficiency. The back is staggered with the main grid and the sub-grid in which the positive and negative electrodes are arranged. In order to avoid short circuits caused by contact between the positive and negative electrodes, insulation operations are often performed between the sub-grids of different polarities, so that the main grids on the back are the same electrode in turn, and form electrical contact with the welding strip. Although there are no grid lines on the front, the grid lines on the back are denser, the silver paste cost is higher, and the sub-grid insulation process is more complicated. Since the existing back-contact cell is provided with a main grid, in addition to insulation between the main grids and between the sub-grids, the main grid and the sub-grid need to be insulated, the process is complicated and the manufacturing cost is high. Summary of the invention

[0004] The purpose of the present invention is to provide a main grid-free back contact battery to solve the technical defects of the prior art that the back contact battery uses a high amount of silver, resulting in high overall manufacturing cost of the battery and complex manufacturing process.

[0005] To solve the above problems, the technical solution adopted by the present invention is: a main grid-free back contact battery, which is composed of multiple battery assemblies connected in series, the battery assembly includes multiple first sub-grid groups, multiple second sub-grid groups, at least one first welding strip and at least one second welding strip, the first sub-grid group and the second sub-grid group are arranged at intervals in front and behind and fixed on the battery sheet of the battery assembly, the first welding strip is connected to the first sub-grid group and is insulated from the second sub-grid group, the second welding strip is connected to the second sub-grid group and is insulated from the first sub-grid group, the first welding strip and the second welding strip serve as the positive and negative electrodes of the battery assembly respectively, the first welding strips of two adjacent battery assemblies are connected to the second welding strips, wherein all the first welding strips of the battery assembly at one end are connected as the positive electrode of the main grid-free back contact battery, and all the second welding strips of the battery assembly at the other end are connected as the negative electrode of the main grid-free back contact battery. The back contact battery of the present invention has no main grid, which reduces the amount of silver used in the battery, thereby reducing the manufacturing cost of the battery. Since the present invention has no main grid, there is no need to perform insulation treatment between the main grid and the auxiliary grid, which simplifies the process and improves the efficiency and yield of the battery. Since the present invention has no main grid, the transmission resistance of the battery itself can be reduced.

[0006] As a further improvement of the present invention, the first sub-grid group includes N first sub-grid units, which are arranged at intervals along the horizontal direction, the N first sub-grid units are collinear, and a first interval of equal width is formed between two adjacent first sub-grid units, and the first intervals of multiple first sub-grid groups correspond front to back, the second sub-grid group includes N second sub-grid units, which are arranged at intervals along the horizontal direction, the N second sub-grid units are collinear, and a second interval of equal width is formed between two adjacent second sub-grid units, the second intervals of multiple second sub-grid groups correspond front to back, the width of the second interval is equal to the width of the first interval, and the second interval is staggered with the first interval left to right, the first sub-grid units on both sides of the first interval are respectively connected by a first welding strip, and the second sub-grid units on both sides of the second interval are respectively connected by a second welding strip, wherein N is an integer greater than 1. The present invention sets a first interval between the first auxiliary grid units, and the first auxiliary grid unit can insulate the first welding strip from the second auxiliary grid unit, and the second interval on the second auxiliary grid unit, and the second auxiliary grid unit can insulate the second welding strip from the first auxiliary grid unit, thereby effectively isolating the first auxiliary grid unit from the second auxiliary grid unit to prevent a short circuit in the battery.

[0007] As a further improvement of the present invention, a second welding strip is arranged in the corresponding first interval of the first auxiliary grid group, the second welding strip crosses and connects with the second auxiliary grid unit, the second welding strip does not contact with the first auxiliary grid unit or is separated by an insulating member, and a first welding strip is arranged in the corresponding second interval of the second auxiliary grid group, the first welding strip crosses and connects with the first auxiliary grid unit, the first welding strip does not contact with the second auxiliary grid unit or is separated by an insulating member. The present invention has good insulation between the positive and negative electrodes and a simple structure.

[0008] As a further improvement of the present invention, the leftmost end of the first sub-grid group is located to the left of the leftmost end of the second sub-grid group, the rightmost end of the second sub-grid group is located to the right of the rightmost end of the first sub-grid group, the left end of the leftmost first sub-grid unit is connected by a third sub-grid unit in the front-to-back direction, and the right end of the rightmost second sub-grid unit is connected by a fourth sub-grid unit in the front-to-back direction. In the present invention, the first sub-grid unit located on the left is connected by the third sub-grid unit, and the second sub-grid unit located on the right is connected by the fourth sub-grid unit, so that the utilization rate of the first sub-grid unit and the second sub-grid unit is higher.

[0009] As a further improvement of the present invention, the rear end of the first welding strip extends backwards to be connected to the front end of the second welding strip of the adjacent battery assembly, and the front end of the second welding strip extends forwards to be connected to the rear end of the first welding strip of the adjacent battery assembly. The structure of the first welding strip and the second welding strip in the present invention makes it easier to connect two adjacent battery assemblies.

[0010] As a further improvement of the present invention, the first welding strip is fixed to the first auxiliary grid group by glue dispensing or coating, and the second welding strip is fixed to the second auxiliary grid group by glue dispensing or coating. The present invention facilitates the fixing of the first auxiliary grid group and the second auxiliary grid group to the first welding strip and the second welding strip.

[0011] In summary, the beneficial effects of the present invention are as follows: the busbar-free back-contact battery of the present invention has no busbar, which reduces the amount of silver used in the battery and reduces the battery cost. The present invention effectively avoids the problem in the prior art that, due to the setting of the main grid, the auxiliary grid with the opposite polarity needs to be insulated near the main grid, which may cause a short circuit if not properly treated. The present invention simplifies the process and improves the efficiency and yield of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the distribution of the first sub-grid group and the second sub-grid group in the present invention.

[0013] Figure 2 It is a schematic diagram of the internal polarity distribution of the battery in the present invention.

[0014] Figure 3 It is another schematic diagram of polarity distribution inside the battery of the present invention.

[0015] Figure 4 It is a schematic diagram of the structure of the battery assembly in the present invention.

[0016] Figure 5 It is a structural schematic diagram of the present invention.

[0017] Among them: 1. battery assembly; 2. first welding strip; 3. second welding strip; 4. first sub-grid unit; 5. first interval; 6. second sub-grid unit; 7. second interval; 8. third sub-grid unit; 9. fourth sub-grid unit. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings.

[0019] The main grid-free back contact battery of the present invention is as follows Figure 5 As shown, it is composed of multiple battery components 1 connected in series, wherein Figure 5 Two battery assemblies 1 are shown, and the battery assemblies 1 include multiple first sub-grid groups, multiple second sub-grid groups, at least one first welding strip 2 and at least one second welding strip 3. The first sub-grid groups and the second sub-grid groups are staggered and arranged at equal intervals front and back and fixed on the battery sheet (not shown in the figure) of the battery assembly 1, that is, the second sub-grid group is between two adjacent first sub-grid groups, and the first sub-grid group is between two adjacent second sub-grid groups. The first welding strip 2 is connected to the first sub-grid group and is insulated from the second sub-grid group, the second welding strip 3 is connected to the second sub-grid group and is insulated from the first sub-grid group, the first welding strip 2 and the second welding strip 3 serve as the positive electrode and negative electrode of the battery assembly 1 respectively, and the first welding strip 2 of two adjacent battery assemblies 1 is connected to the second welding strip 3, wherein all the first welding strips 2 of the battery assembly 1 at one end are connected as the positive electrode of the battery without main grid back contact, and all the second welding strips 3 of the battery assembly 1 at the other end are connected as the negative electrode of the battery without main grid back contact.

[0020] like Figure 1As shown, the first auxiliary grid group in the present invention includes N first auxiliary grid units 4, the N first auxiliary grid units 4 are arranged at intervals in the horizontal direction, the N first auxiliary grid units 4 are collinear, and a first interval 5 of equal width is formed between two adjacent first auxiliary grid units 4, the width of the first interval 5 is greater than the width of the second welding strip 3, the first intervals 5 of the plurality of first auxiliary grid groups correspond to each other front and back, and N-1 first intervals 5 are formed between the N first auxiliary grid units 4 of the first auxiliary grid group, and the second auxiliary grid group includes N second auxiliary grid units 6, the N second auxiliary grid units 6 are arranged at intervals in the horizontal direction, the N second auxiliary grid units 6 are collinear, and a first interval 5 of equal width is formed between two adjacent second auxiliary grid units 6. The second grid units 7 are formed into equal widths, the width of the second grid units 7 is greater than the width of the first welding strip 2, the second grid units 7 of the plurality of second grid groups correspond to each other front to back, N-1 second grid units 7 are formed between the N second grid units 6 of the second grid group, the width of the second grid units 7 is equal to the width of the first grid units 5, and the second grid units 7 are staggered with the first grid units 5 left and right, the first grid units 4 on both sides of the first grid units 5 are respectively connected by a first welding strip 2, and the second grid units 6 on both sides of the second grid units 7 are respectively connected by a second welding strip 3 of one pole, N in the present invention is an integer greater than 1, and the polarity distribution formed by the first grid unit 4 and the second grid unit 6 in the present invention is as follows: Figure 2 or Figure 3 shown.

[0021] like Figure 4 As shown, in the present invention, a second welding strip 3 is arranged in the first interval 5 corresponding to the front and back of the first auxiliary grid group, and the second welding strip 3 is cross-connected with the second auxiliary grid unit 6 and connected, and the second welding strip 3 is not in contact with the first auxiliary grid unit 4 or is separated by an insulating member. The best embodiment of the present invention wraps an insulating member on the second welding strip 3 to be insulated and separated from the first auxiliary grid unit 4, and the second auxiliary grid unit 6 is electrically connected to the second welding strip 3 through the insulating member on the second welding strip 3. A first welding strip 2 is arranged in the second interval 7 corresponding to the front and back of the second auxiliary grid group, and the first welding strip 2 is cross-connected with the first auxiliary grid unit 4 and connected, and the first welding strip 2 is not in contact with the second auxiliary grid unit 6 or is separated by an insulating member. The present invention wraps an insulating member on the first welding strip 2 to be insulated and separated from the second auxiliary grid unit 4, and the first auxiliary grid unit 4 is electrically connected to the first welding strip 2 through the insulating member on the first welding strip 2. The insulating member in the present invention is a prior art and will not be described in detail in the present invention.

[0022] like Figure 1 As shown, the leftmost end of the first sub-grid group in the present invention is located on the left side of the leftmost end of the second sub-grid group, and the rightmost end of the second sub-grid group is located on the right side of the rightmost end of the first sub-grid group, so that the first interval 5 and the second interval 7 are staggered left and right, and the left end of the leftmost first sub-grid unit 4 is connected by a third sub-grid unit 8 in the front-to-back direction, and the right end of the rightmost second sub-grid unit 6 is connected by a fourth sub-grid unit 9 in the front-to-back direction.

[0023] like Figure 4 As shown, the rear end of the first welding strip 2 in the present invention extends backwards to be connected to the front end of the second welding strip 3 of the battery assembly 1 adjacent to its rear, and the front end of the second welding strip 3 extends forwards to be connected to the rear end of the first welding strip 2 of the battery assembly 1 adjacent to its front. When connecting two battery assemblies 1, the present invention first places one battery assembly 1, and then takes another battery assembly 1 and rotates it 180 degrees forward and backward to connect it to the aforementioned battery assembly 1.

[0024] The first welding strip 2 in the present invention is fixed to the first sub-grid group by dispensing or coating, and the second welding strip 3 is fixed to the second sub-grid group by dispensing or coating. The first welding strip 2 and the second welding strip 3 in the present invention are respectively fixed to the first sub-grid group and the second sub-grid group by dispensing.

[0025] The parts not specifically described in the above description are all prior art, or can be implemented by prior art. Moreover, the specific implementation cases described in the present invention are only preferred implementation cases of the present invention, and are not used to limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made according to the content of the patent scope of the present invention should be regarded as the technical scope of the present invention.

Claims

1. A busbar-free back contact battery, which is composed of multiple battery modules connected in series, characterized by: The battery assembly includes multiple first sub-grid groups, multiple second sub-grid groups, at least one first welding strip and at least one second welding strip. The first sub-grid groups and the second sub-grid groups are arranged at intervals in front and back and fixed on the battery cells of the battery assembly. The first welding strip is connected to the first sub-grid group and is insulated from the second sub-grid group. The second welding strip is connected to the second sub-grid group and is insulated from the first sub-grid group. The first welding strip and the second welding strip serve as the positive electrode and negative electrode of the battery assembly respectively. The first welding strip of two adjacent battery assemblies is connected to the second welding strip, wherein all the first welding strips of the battery assembly at one end are connected as the positive electrode of the battery without main grid back contact, and all the second welding strips of the battery assembly at the other end are connected as the negative electrode of the battery without main grid back contact.

2. The busbar-free back contact cell according to claim 1, characterized in that: The first sub-grid group includes N first sub-grid units, which are arranged at intervals along the horizontal direction, the N first sub-grid units are collinear, and a first interval of equal width is formed between two adjacent first sub-grid units, and the first intervals of the plurality of first sub-grid groups correspond front to back. The second sub-grid group includes N second sub-grid units, which are arranged at intervals along the horizontal direction, the N second sub-grid units are collinear, and a second interval of equal width is formed between two adjacent second sub-grid units, and the second intervals of the plurality of second sub-grid groups correspond front to back, the width of the second interval is equal to the width of the first interval, and the second interval is staggered with the first interval left to right, the first sub-grid units on both sides of the first interval are respectively connected by a first welding strip, and the second sub-grid units on both sides of the second interval are respectively connected by a second welding strip, wherein N is an integer greater than 1.

3. The busbar-free back contact cell according to claim 2, characterized in that: A second welding strip is arranged in the corresponding first interval of the first auxiliary grid group, and the second welding strip crosses and is connected to the second auxiliary grid unit. The second welding strip does not contact the first auxiliary grid unit or is separated by an insulating member. A first welding strip is arranged in the corresponding second interval of the second auxiliary grid group, and the first welding strip crosses and is connected to the first auxiliary grid unit. The first welding strip does not contact the second auxiliary grid unit or is separated by an insulating member.

4. The main grid back contact battery according to claim 2, characterized in that: The leftmost end of the first sub-grid group is located to the left of the leftmost end of the second sub-grid group, the rightmost end of the second sub-grid group is located to the right of the rightmost end of the first sub-grid group, the left end of the leftmost first sub-grid unit is connected by a third sub-grid unit in the front-to-back direction, and the right end of the rightmost second sub-grid unit is connected by a fourth sub-grid unit in the front-to-back direction.

5. The main grid back contact battery according to claim 2, characterized in that: The rear end of the first welding strip extends backwards to be connected to the front end of the second welding strip of the adjacent battery assembly, and the front end of the second welding strip extends forwards to be connected to the rear end of the first welding strip of the adjacent battery assembly.

6. The main grid back contact battery according to any one of claims 1 to 5, characterized in that: The first welding strip is fixed to the first auxiliary grid group by means of glue dispensing or film coating, and the second welding strip is fixed to the second auxiliary grid group by means of glue dispensing or film coating.

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