Solder strip suitable for main-grid-free back contact battery

Abstract

The invention discloses a welding strip suitable for a main-grid-free back contact battery, which comprises M rows of first auxiliary grids and M rows or (M + 1) rows of second auxiliary grids, each row of first auxiliary grids comprises N first auxiliary grid units, N-1 first intervals are formed between two adjacent first auxiliary grid units, each row of second auxiliary grids comprises N second auxiliary grid units, N is a positive integer, N is a positive integer, N is a positive integer, N is a positive integer, and N is a positive integer. N-1 second intervals are formed between every two adjacent second auxiliary grid units, the first welding strips penetrate through the first intervals in the front-back direction and are insulated from the first auxiliary grid units, the first welding strips and the second auxiliary grid units are crossed and electrically connected, and N-1 second intervals are formed between every two adjacent second auxiliary grid units. The second welding strips penetrate through the second intervals in the front-back direction and are insulated from the second auxiliary grid units, and the second welding strips and the first auxiliary grid units are crossed and electrically connected. The manufactured back contact battery is free of a main grid, the silver consumption for manufacturing the battery is reduced, and mutual contact of the first auxiliary grid and the second auxiliary grid is avoided by using insulating materials on the two sides of the welding strip.

Description

Technical Field

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

[0002] Back contact cells are cells that have both the PN junction and the metal contact on the back of the solar cell. The front of the cell uses a double-layer SiNx / SiOx anti-reflection passivation film, which is not blocked by metal electrodes. This maximizes the use of incident light, reduces optical losses, brings more effective power generation area, has high conversion efficiency, and is more beautiful in appearance. In order to reduce costs and increase efficiency, busbar-free cells can reduce the amount of silver paste used in the cell by eliminating the busbar, thereby achieving the purpose of reducing costs. However, the PN junction of busbar-free back contact cells is set on the back of the cell. Once the solder strip is too thick or offset, it will cause an internal short circuit in the cell. Therefore, there are still difficulties that need to be solved in the current production of busbar-free back contact cells.

[0003] The existing back-contact battery has a staggered arrangement of the main grid and the auxiliary grid, and the battery is made of low-temperature silver paste. Due to the existence of the main grid, a large amount of silver paste is used, which leads to a high manufacturing cost of the back-contact battery. In order to avoid the contact of the staggered positive and negative electrodes and cause an internal short circuit in the battery, insulation operations are often performed between the auxiliary grids of different polarities, so that the main grids on the back are the same electrode in turn, and then electrical contact is formed using welding strips. The back-contact main-grid-free battery has no back main grid, so the precision of the welding machine is required to be higher during string welding. Once the welding strip is too thick or offset, it will cause a short circuit. Summary of the invention

[0004] The purpose of the present invention is to provide a welding strip suitable for a main grid-free back contact battery, so as to solve the technical defects in the prior art that the battery has a main grid and a secondary grid at the same time, a large amount of silver paste is used during battery manufacturing, the overall manufacturing cost of the battery is high, and short circuits are prone to occur inside the battery, which affects the battery life.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is: a welding strip suitable for a busbar-free back contact battery, comprising M rows of first sub-grids and M rows or M+1 rows of second sub-grids, the first sub-grids and the second sub-grids are fixed on the back of the busbar-free back contact battery, the M rows of first sub-grids and the M rows or M+1 rows of second sub-grids are alternately arranged in a front-to-back direction, each row of the first sub-grids comprises N first sub-grid units, the N first sub-grid units are spaced in a left-to-right direction, and a total of N-1 first intervals are formed between two adjacent first sub-grid units, the first intervals on the M rows of the first sub-grids correspond to each other front-to-back, each row of the second sub-grids comprises N second sub-grid units, and the N first sub-grid units are spaced in a left-to-right direction. The second sub-grid units are spaced apart in the left-right direction, and a total of N-1 second intervals are formed between two adjacent second sub-grid units, wherein the second intervals are staggered with the first intervals in the left-right direction, and the second intervals on the M rows or M+1 rows of the second sub-grids correspond to each other front to back, wherein M and N are both integers greater than 1, and also include a first welding strip and a second welding strip, the first welding strip passes through the first interval in the front-to-back direction respectively and is insulated from the first sub-grid unit, the first welding strip crosses and is electrically connected to the second sub-grid unit, the second welding strip passes through the second interval in the front-to-back direction respectively and is insulated from the second sub-grid unit, and the second welding strip crosses and is electrically connected to the first sub-grid unit. The welding strip structure of the present invention makes the battery without a main grid, reduces the amount of silver paste used in battery manufacturing, and reduces the manufacturing cost of the battery. The first welding strip and the second welding strip in the present invention are only connected to the second sub-grid and the first sub-grid, respectively, so that the internal short circuit of the battery can be effectively avoided and the service life of the battery can be improved.

[0006] As a further improvement of the present invention, the first welding strip and the second welding strip both include a copper substrate, and a tin-lead low-temperature coating is provided on both the upper and lower sides of the copper substrate, and an insulating oxide is provided on both the left and right sides of the copper substrate, and the upper and lower ends of the insulating oxide are respectively connected to the tin-lead low-temperature coating on the upper and lower sides of the copper substrate, wherein the insulating oxide on both sides of the first welding strip is used to insulate the first auxiliary grid unit, and the end of the second auxiliary grid unit passes through the insulating oxide on both sides of the first welding strip and is connected to the copper substrate of the first welding strip, and the insulating oxide on both sides of the second welding strip is used to insulate the second auxiliary grid unit, and the end of the first auxiliary grid unit passes through the insulating oxide on both sides of the second welding strip and is connected to the copper substrate of the second welding strip. The copper substrate in the present invention is used for conducting electricity, and the insulating oxide can be used to separate the copper substrate from the first auxiliary grid unit or the second auxiliary grid unit, so as to separate the positive electrode from the negative electrode of the main grid back contactless battery, and avoid internal short circuit of the main grid back contactless battery.

[0007] As a further improvement of the present invention, the insulating oxide is an inorganic substance.

[0008] As a further improvement of the present invention, the insulating oxide is silicon dioxide.

[0009] As a further improvement of the present invention, the first and second auxiliary grids are fixed to the back of the busbar-free back contact battery by dispensing or coating. In the present invention, the first and second auxiliary grids are firmly and conveniently fixed to the busbar-free back contact battery.

[0010] As a further improvement of the present invention, the cross-sectional shape of the copper substrate is rectangular, wherein the cross-sectional shapes of the insulating oxide and the tin-lead low-temperature coating are both rectangular, and the insulating oxide and the tin-lead low-temperature coating are both in contact with the surface of the copper substrate. The shapes of the first welding strip and the second welding strip in the present invention enable them to be in contact with the back of the battery without a main grid back contact when in use, and the overall fixation is more secure.

[0011] As a further improvement of the present invention, the cross-sectional shape of the copper substrate is rectangular, wherein the insulating oxide and the tin-lead low-temperature coating are both in contact with the surface of the copper substrate, the surface of the insulating oxide and the tin-lead low-temperature coating away from the copper substrate is an arc surface, and the surface of the insulating oxide and the tin-lead low-temperature coating away from the copper substrate is located on the same cylindrical surface. The shape of the first welding strip and the second welding strip in the present invention increases the thickness in the middle of the copper substrate, thereby increasing the distance between the copper substrate and the back of the battery without main grid back contact.

[0012] In summary, the beneficial effects of the present invention are as follows: the back-contact battery made by the present invention has no main grid, which reduces the amount of silver used in manufacturing the battery and reduces the manufacturing cost of the battery. The welding strip and the auxiliary grid in the present invention have good insulation properties. By using insulating materials on both sides of the welding strip, the mutual contact between the first auxiliary grid and the second auxiliary grid is avoided, thereby increasing the welding fault tolerance of the main grid-free back-contact battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the arrangement of the first sub-grid and the second sub-grid in the present invention.

[0014] Figure 2 It is a structural schematic diagram of the present invention.

[0015] Figure 3 It is a schematic longitudinal cross-sectional view of the first welding strip or the second welding strip in Example 1 of the present invention.

[0016] Figure 4 It is a schematic longitudinal cross-sectional view of the first welding strip or the second welding strip in Example 2 of the present invention.

[0017] Among them: 1. first sub-gate unit; 2. first interval; 3. second sub-gate unit; 4. second interval; 5. first welding strip; 6. second welding strip; 7. copper substrate; 8. tin-lead low-temperature coating; 9. insulating oxide. DETAILED DESCRIPTION

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

[0019] Example 1

[0020] like Figure 1 and Figure 2 The welding strip suitable for a busbar-free back contact battery shown in the figure comprises M rows of first sub-grids and M rows or M+1 rows of second sub-grids, the first sub-grids and the second sub-grids are fixed on the back of the busbar-free back contact battery, and the first sub-grids and the second sub-grids in this embodiment are preferably fixed on the back of the busbar-free back contact battery by dispensing or laminating, wherein the busbar-free back contact battery is made of low-temperature silver paste, and its melting temperature is 110-160° C., M rows of first sub-grids and M rows or M+1 rows of second sub-grids are alternately arranged in the front-to-back direction, and each row of the first sub-grids comprises N horizontally arranged first sub-grid units 1, and the N first sub-grid units 1 are spaced and distributed in the left-right direction and are located on the same horizontal line, and between two adjacent N-1 first intervals 2 are formed between the first auxiliary grid units 1, and the widths of all the first intervals 2 are equal. The first intervals 2 on the M rows of the first auxiliary grids correspond to each other front to back. Each row of the second auxiliary grid includes N horizontally arranged second auxiliary grid units 3, and the N second auxiliary grid units 3 are spaced and distributed along the left and right directions and are located on the same horizontal line. N-1 second intervals 4 are formed between two adjacent second auxiliary grid units 3, and the widths of all the second intervals 2 are equal. The second intervals 4 are staggered with the first intervals 2 left and right, and the widths of the first intervals 2 and the fourth intervals 4 are equal. The second intervals 4 on the M rows or M+1 rows of the second auxiliary grids correspond to each other front to back, and M and N are both integers greater than 1. Figure 1 As shown, in this embodiment, the second auxiliary grid is preferably set to be equal to the first auxiliary grid, wherein Figure 2 Taking M9 as an example, in this embodiment, the distance between the adjacent first auxiliary gate unit 1 and the second auxiliary gate unit 3 is 0.8-2 mm, and the width of the first interval 2 and the second interval 4 is 0.5-1 mm.

[0021] like Figure 2As shown, in this embodiment, a first welding strip 5 and a second welding strip 6 are provided. The first welding strip 5 passes through the first interval 2 along the front-to-back direction and is insulated from the first auxiliary grid unit 1. In this embodiment, the first welding strip 5 is set to be not connected to the first auxiliary grid unit 1 to achieve insulation between the two, or an insulating member is set on the first welding strip 5 to achieve insulation from the first auxiliary grid unit 1. The first welding strip 5 crosses and electrically connects with the second auxiliary grid unit 3, that is, the first welding strip 5 is directly connected to the second auxiliary grid unit 3, and the second welding strip 6 passes through the second interval 4 along the front-to-back direction and is insulated from the second auxiliary grid unit 3. In this embodiment, the second welding strip 6 is not connected to the second interval 4. , so that the two are insulated, or an insulating member is arranged on the second welding strip 6 to achieve insulation between the two, the second welding strip 6 crosses the first auxiliary grid unit 1 and is directly connected, so that the second welding strip 6 is electrically connected to the first auxiliary grid unit 1, in this embodiment, the left end of the first auxiliary grid unit 1 is more to the left than the left end of the second auxiliary grid unit 3, and the right end of the second auxiliary grid unit 3 is more to the right than the right end of the first auxiliary grid unit 1, a second welding strip 6 is used to connect the leftmost end of the first auxiliary grid unit 1, and the second welding strip 6 is insulated from the second auxiliary grid unit 3, and a first welding strip 5 is used to connect the rightmost end of the second auxiliary grid unit 3, and the first welding strip 5 is insulated from the first auxiliary grid unit 1.

[0022] like Figure 2 and Figure 3 As shown, the first welding strip 5 and the second welding strip 6 in this embodiment have the same structure, both including a copper substrate 7, and tin-lead low-temperature coatings 8 are provided on the upper and lower sides of the copper substrate 7, wherein the tin-lead low-temperature coating 8 on the top of the copper substrate 7 is used to separate the copper substrate 7 from the main grid back contact battery, and insulating oxides 9 are provided on the left and right sides of the copper substrate 7, and the upper and lower ends of the insulating oxides 9 are respectively connected to the ends of the tin-lead low-temperature coatings 8 on the upper and lower sides of the copper substrate 7, wherein the insulating oxides 9 on both sides of the first welding strip 5 are used to separate the copper substrate 7 of the first welding strip 5 from the first auxiliary grid unit 1, so that the first welding strip 5 is insulated from the first auxiliary grid unit 1, and the end of the second auxiliary grid unit 3 is connected to the copper substrate 7 of the first welding strip 5 through the insulating oxides 9 on both sides of the first welding strip 5, and the insulating oxides 9 on both sides of the second welding strip 6 are used to separate the copper substrate 7 of the second welding strip 6 from the second auxiliary grid unit 3, so that the second welding strip 6 is insulated from the second auxiliary grid unit 3, and the end of the first auxiliary grid unit 1 is connected to the copper substrate 7 of the second welding strip 6 through the insulating oxides 9 on both sides of the second welding strip 6. The insulating oxide 9 in this embodiment is an inorganic substance, and the insulating oxide 9 in this embodiment is silicon dioxide.

[0023] like Figure 3 As shown, the longitudinal cross-section of the copper substrate 7 in this embodiment is a rectangle, wherein the longitudinal cross-sections of the insulating oxide 9 and the tin-lead low-temperature coating 8 are also rectangular, the insulating oxide 9 and the tin-lead low-temperature coating 8 are both in contact with the surface of the copper substrate 7, and the first welding strip 5 and the second welding strip 6 in this embodiment are both cuboid.

[0024] The first welding strip 5 of this embodiment serves as the positive electrode of the power supply, and the second welding strip 6 serves as the negative electrode of the power supply, wherein the front end of the first welding strip 5 extends forward, and the rear end of the second welding strip 6 extends backward. When in use, multiple embodiments of the present invention are connected in series, wherein the first welding strips 5 of two adjacent embodiments of the present invention are respectively connected to the second welding strips 6 to form a battery pack, and then all the first welding strips 5 of the battery pack are connected, and all the second welding strips 6 of the battery pack are connected, which serve as the positive and negative electrodes of the battery pack, respectively, for connecting a load and outputting electrical energy to the load.

[0025] Example 2

[0026] This embodiment is a further improvement made on the basis of the embodiment 1. Compared with the embodiment 1, the cross-sectional shape of the copper substrate 7 in this embodiment is rectangular, wherein the insulating oxide 9 and the tin-lead low-temperature coating 8 are both in contact with the surface of the copper substrate 7, and the surface of the insulating oxide 9 and the tin-lead low-temperature coating 8 away from the copper substrate 7 is an arc surface, and the surface of the insulating oxide 9 and the tin-lead low-temperature coating 8 away from the copper substrate 7 is located on the same cylindrical surface, so that the first welding strip 5 and the second welding strip 6 are both cylindrical, as shown in FIG. Figure 4 The remaining structures of this embodiment are the same as those of embodiment 1, and the details can be referred to embodiment 1, which will not be described in detail in this embodiment.

[0027] 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 welding strip suitable for a busbar-free back contact battery, comprising M rows of first sub-grids and M rows or M+1 rows of second sub-grids, wherein the first sub-grids and the second sub-grids are fixed on the back of the busbar-free back contact battery, wherein the M rows of first sub-grids and the M rows or M+1 rows of second sub-grids are alternately arranged in a front-to-back direction, wherein each row of the first sub-grids comprises N first sub-grid units, wherein the N first sub-grid units are spaced in a left-to-right direction, and a total of N-1 first intervals are formed between two adjacent first sub-grid units, wherein the first intervals on the M rows of the first sub-grids correspond to each other in a front-to-back direction, wherein each row of the second sub-grids comprises N second sub-grid units, wherein the N second sub-grid units are spaced in a left-to-right direction, and a total of N-1 second intervals are formed between two adjacent second sub-grid units, wherein the second intervals are staggered with the first intervals in a left-to-right direction, and the second intervals on the M rows or M+1 rows of the second sub-grids correspond to each other in a front-to-back direction, wherein both M and N are integers greater than 1, and wherein: It also includes a first welding strip and a second welding strip, the first welding strip passes through the first gap along the front-to-back direction and is insulated from the first auxiliary grid unit, the first welding strip crosses the second auxiliary grid unit and is electrically connected, the second welding strip passes through the second gap along the front-to-back direction and is insulated from the second auxiliary grid unit, the second welding strip crosses the first auxiliary grid unit and is electrically connected.

2. The welding strip suitable for a busbar-free back contact battery according to claim 1, characterized in that: The first welding strip and the second welding strip both include a copper substrate, tin-lead low-temperature coatings are provided on the upper and lower sides of the copper substrate, insulating oxides are provided on the left and right sides of the copper substrate, and the upper and lower ends of the insulating oxides are respectively connected to the tin-lead low-temperature coatings on the upper and lower sides of the copper substrate, wherein the insulating oxides on both sides of the first welding strip are used to insulate the first sub-grid unit, and the end of the second sub-grid unit passes through the insulating oxides on both sides of the first welding strip and is connected to the copper substrate of the first welding strip, and the insulating oxides on both sides of the second welding strip are used to insulate the second sub-grid unit, and the end of the first sub-grid unit passes through the insulating oxides on both sides of the second welding strip and is connected to the copper substrate of the second welding strip.

3. The welding strip suitable for a busbar-free back contact battery according to claim 2, characterized in that: Insulating oxides are inorganic substances.

4. The welding strip suitable for a busbar-free back contact battery according to claim 2, characterized in that: The insulating oxide is silicon dioxide.

5. The welding strip suitable for a busbar-free back contact battery according to claim 1, characterized in that: The first sub-grid and the second sub-grid are fixed on the back side of the main-grid-free back contact battery by means of glue dispensing or film coating.

6. The welding strip suitable for a busbar-free back contact battery according to claim 2, characterized in that: The cross-sectional shape of the copper substrate is rectangular, wherein the cross-sectional shapes of the insulating oxide and the tin-lead low-temperature coating are both rectangular, and the insulating oxide and the tin-lead low-temperature coating are both in contact with the surface of the copper substrate.

7. The welding strip suitable for a busbar-free back contact battery according to claim 2, characterized in that: The cross-sectional shape of the copper substrate is rectangular, wherein the insulating oxide and the tin-lead low-temperature coating are both in contact with the surface of the copper substrate, the surfaces of the insulating oxide and the tin-lead low-temperature coating away from the copper substrate are arc surfaces, and the surfaces of the insulating oxide and the tin-lead low-temperature coating away from the copper substrate are located on the same cylindrical surface.

Images