solar panel

Abstract

Solar module (1) consisting of several series- and parallel-connected solar cell strings, wherein a first U-shaped, single-row solar cell string (21) is arranged in a first half (A) of the solar module with its start and end contacts pointing towards the module center, wherein a second, single-row solar cell string (22) is arranged in a second half (B) of the solar module in a mirror image of the first solar cell string, wherein the start contact of the first solar cell string (21) is connected to a start contact of the second solar cell string (22) via a first center connector (31) located in a central region (MB), wherein the end contacts of the first and second solar cell strings (21, 22) are connected via a second center connector (32) located in the central region (MB) to an initial contact of a third, double-row and U-shaped solar cell string (23) which is arranged in the first module half (A), wherein the end contact of the third solar cell string (23) is connected to a third center connector (33) arranged in the center region (MB) with the initial contact of a fourth, double-row, U-shaped solar cell string (24) arranged in the second module half (B), wherein the end contact of the fourth solar cell string (24) is contacted with a fourth center connector (34) arranged in the center region (MB), and wherein the fourth center connector (34) is arranged at least partially parallel to, electrically insulated from, the second center connector (32) and next to or above the second center connector (32).

Description

[0001] The present invention relates to a solar module consisting of several solar cell strings connected in series and in parallel, wherein center connectors are also installed to connect the solar cell strings.

[0002] Photovoltaics is recognized as one of the technologies contributing to the transition from fossil fuels to renewable energies. It is important that solar modules are manufactured in an energetically and economically efficient manner. The specific arrangement of individual components such as the solar cells, the electrical center connectors, the junction boxes, the bridging elements, and the connecting cables also plays an important role. This arrangement influences not only the manufacturing costs but also the electrical efficiency of the solar module.

[0003] Solar modules are often manufactured using solar cell strings consisting of solar cells connected in series. These are also referred to as "solar cell strings." Solar cell strings or solar cell substrings are connected in series and / or parallel using electrical center connectors to form a solar cell array, which forms the basis for the module's electrical design.

[0004] Solar modules also consist of a front-side protection element and a back-side protection element. At least on the light-exposed side, this element is made of a light-transparent material such as glass. On the opposite side, the light-exposed side, this element can also be made of an opaque material such as a polymer film. The electrically active solar cells are also often embedded with a polymer material between the front-side and back-side protection elements.

[0005] The solar module's electrical power is typically routed through the back protection element via a positive and negative electrical connector on the back side, away from the light incidence. These electrical connectors are connected to external connecting cables in one or more junction boxes mounted on the outside of the back protection element. Bridging elements can also be connected to the electrical connectors.

[0006] To prevent harmful local overheating in the event of partial shading, bridging elements must be provided after a certain number of solar cells connected in series. These are often implemented using high-current diodes and are commonly referred to as "bypass diodes." Alternatively, electronic switching elements can also be used. Due to the mechanical size of the bridging elements, it is advantageous to house them outside the assembly of front-side protection element, solar cells, and rear-side protection element in the junction boxes.

[0007] Due to the size of solar cells used today, for example, with a side length greater than 156 mm, it can be advantageous to divide individual solar cells into sub-cells. This reduces ohmic losses in contact wires used to electrically connect solar cells to neighboring solar cells. At the same time, however, the number of solar cells in a solar module is doubled while maintaining a similar output power. To avoid doubling the output voltage of a solar module made with half-cells, it is therefore necessary to connect the solar cells or solar cell strings, at least partially, in parallel.

[0008] European patent DE202013005357U1 discloses various arrangements in which solar cells are connected in series and parallel in multiple solar cell strings. Connecting the solar cells requires a plurality of parallel electrical center connectors and / or a large number of junction boxes. These lead to significant manufacturing costs for the modules, with disadvantages in terms of the processing time required and high material costs.

[0009] The object of the present invention is to provide a solar module that can be produced cost-effectively and has a high electrical efficiency by means of a favorable arrangement of the solar cells, the solar cell strings, the electrical center connectors and the connection boxes.

[0010] The object is achieved by a solar module which consists of several solar cell strings connected in series and in parallel, wherein a first U-shaped, single-row solar cell string is arranged in a first half of the solar module with its starting and end contact pointing towards the module center, wherein a second, single-row solar cell string is arranged in a second half of the solar module as a mirror image of the first solar cell string, wherein the starting contact of the first solar cell string is connected to a starting contact of the second solar cell string via a first center connector located in a center region, wherein the end contacts of the first and second solar cell strings are connected to a starting contact of a third, double-row and U-shaped solar cell string, which is arranged in the first module half, via a second center connector located in the center region,wherein the end contact of the third solar cell string is connected to a third center connector arranged in the center region with the starting contact of a fourth, two-row, U-shaped solar cell string arranged in the second module half, wherein the end contact of the fourth solar cell string is contacted to a fourth center connector arranged in the center region, wherein the fourth center connector is arranged at least partially parallel, electrically insulated from each other, next to each other or one above the other to the second center connector.

[0011] The present invention enables a particularly cost-effective production of a solar module through a favorable arrangement of the solar cells, the solar cell strings composed of them, using electrical connectors, and the arrangement of the junction boxes. The aim is to produce a solar module with high electrical efficiency while avoiding losses due to the high complexity of connecting the solar cells and the junction boxes. Furthermore, the clever interconnection of the solar cells and solar cell strings, as well as the arrangement of the connectors, should avoid an unnecessarily large module surface area.

[0012] The invention is particularly suitable for applications where a large number of solar cells, for example, more than 60, are interconnected in a solar module. For large solar cells, for example, with an edge length greater than 125 mm or even greater than 156 mm, ohmic losses during contacting can be reduced by dividing them into solar sub-cells. With serial interconnection along the shorter edge of the solar cell, ohmic losses can be reduced by shortening the length of the interconnection contacts. Therefore, it is sensible to connect individual solar cells in a solar module in series to increase the module voltage and in parallel to increase the current in the module. The invention is also particularly suitable for interconnecting solar sub-cells, such as half, third, or quarter cells, but can also be used for full cells.

[0013] Another design feature is that, for safe operation of a solar module in the event of partial shading of the module, bridging elements must be provided after a certain number of series-connected solar cells, for example, after approximately 20 solar cells. These bridging elements prevent local overheating in the area where a solar cell or solar cell region generates less current than the rest of the solar module due to shading. These bridging elements must therefore be connected between a starting contact and an end contact of a certain number of series-connected solar cells.

[0014] For an efficient module design, the optimal positioning of the junction boxes must also be considered. A favorable compromise must be found between the size, number, and positioning of the junction boxes.

[0015] The invention shows a favorable solution for the tasks described above through a special arrangement of the solar cells and solar cell strings, the connectors connecting the solar cell strings, the connection boxes and the bridging elements.

[0016] In the solar module according to the invention, a first U-shaped, single-row solar cell string is arranged in a first half A of the solar module with its start and end contact (or the top of the U) towards the center of the module. Single-row means that individual solar cells or solar sub-cells are contacted by means of electrical connectors in a series connection. A first half of the string is arranged running in one direction and a second half of the solar cell string is connected in an opposite direction, parallel to the first half. The two halves of the solar cell string are electrically connected in their center, at a reversal point, with an external connector. Running in one direction means that the photovoltage in a solar module illuminated by sunlight increases or decreases by one solar cell voltage after each solar cell in the series connection. If, for example,If the first center contact is the negative pole of a solar module made up of 120 silicon heterojunction solar half-cells, then the voltage in the first halves of the first and second solar cell string increases from the middle to the outer solar half-cell by approximately 0.75 V per solar half-cell, so that a voltage of approximately 7.5 V is applied to each of the first and second outer connectors. After the second half of the first and second strings, a voltage of approximately 15 V is applied to the second center connector.

[0017] Mirroring the first solar cell string, the second, single-row and U-shaped solar cell string is arranged in a second half of the solar module.

[0018] The initial contact of the first solar cell string is connected to an initial contact of the second solar cell string via a first center connector located in a central region. The second solar cell string is also electrically connected to an outer connector at a reversal point.

[0019] This means that individual solar cells in the first and second single-row solar cell strings are electrically connected in series. The first and second center connectors electrically connect the first and second solar cell strings in parallel.

[0020] The center line separates the first half of the solar module from the second half. This statement refers to the top view of the solar module, looking in the direction of the incident light. The center area is a strip-shaped area in which the center line also lies. The center area extends over an upper distance from the center line, which lies in the first (or upper) half of the module, and also over a lower distance, which lies in the second (or lower) half of the module. The distance from the center line can range from 5 mm to 40 mm.

[0021] The end contacts of the first and second solar cell strings are connected via a second center connector located in the center of the solar module to a start contact of a third, two-row, U-shaped solar cell string arranged in the first module half A. A two-row, U-shaped arrangement means that in a first half, two solar cell sub-strings are connected in series, parallel to one another, in one direction, and in a second half, two solar cell sub-strings are connected in series, parallel to one another, in a second direction, opposite to the first direction. The first two-row half and the second two-row half are connected at a reversal point with an electrical external connector. The two solar cell sub-strings of the third two-row solar cell string are also electrically connected in parallel via the second center connector, the first two-row external connector, and the third center connector.(The third double-row solar cell string is the third solar cell string described and is therefore labeled “third.”)

[0022] Furthermore, the end contact of the third two-row solar cell string is connected to the starting contact of a fourth, two-row, U-shaped solar cell string via a third center connector located in the center of the solar module. The fourth solar cell string is arranged in the second module half B, rotated 180 degrees relative to the third solar cell string. The U-shaped solar cell string is electrically connected at its reversal point to a second two-row outer connector.

[0023] The end contact of the fourth solar cell string is contacted with a fourth center connector arranged in the center of the solar module.

[0024] The two solar cell substrings of the fourth solar cell string are connected in parallel to the third center connector, the second two-row outer connector, and the fourth center connector. The structure of the fourth solar cell string is similar to that of the third solar cell string.

[0025] The fourth center connector is arranged at least partially parallel to the second center connector in the center region. The fourth center connector and the second center connector are electrically insulated from each other and, in plan view, are arranged either side by side or one above the other. The fourth center connector can, for example, be arranged parallel to the second center connector at a certain distance.

[0026] Alternatively, the fourth center connector can be arranged above or below the second center connector, outside the viewing plane, and at least partially overlapping it. To ensure electrical insulation, an insulating material can be applied between the connectors. Alternatively or additionally, the electrical insulation can be achieved by an insulating coating on at least one of the connectors. This coating can be applied at least in the area where the connectors overlap.

[0027] All center connectors are arranged in a center region MB of the solar module. The center region MB can be larger than the distance between the solar cell strings and the center line MM of the solar module. The center connectors can also be arranged, at least in part, below a solar cell string.

[0028] The initial contact of the solar module can be formed by the first center connector. The first center connector can be electrically connected to a first contact element in a first connection box. The final contact of the solar module can be formed by the fourth center connector. The fourth center connector can be contacted to a fifth contact element in a second connection box.

[0029] The second center connector can be electrically contacted with a second contact element in a first connection box and electrically contacted with a third contact element in a second connection box.

[0030] The third center connector may be electrically connected to a fourth contact element in a second junction box.

[0031] This arrangement has the effect that, on the one hand, the solar module structure is simple with only two junction boxes and, on the other hand, overlapping of junction boxes and solar cells can be avoided by using several small junction boxes.

[0032] A first bridging element can be electrically connected between the first center connector and the second center connector.

[0033] A second bridging element can be connected between the second center connector and the third center connector.

[0034] A third bridging element can be connected between the third center connector and the fourth center connector.

[0035] The first bridging element can be arranged in the first connection box and be electrically contacted with the first and second contact elements.

[0036] The second bridging element can be arranged in the second connection box and can be electrically contacted or connected to the third and fourth contact elements.

[0037] The third bridging element can be arranged in the second connection box and be electrically contacted with the fourth and fifth contact elements.

[0038] The bridging elements can be made of diodes or electronic switching elements. They serve to provide electrical bridging in the event of partial shading of a solar cell string.

[0039] Each of the center connectors can consist of a single, continuous electrical conductor or be composed of multiple electrical conductors. The mechanical and electrical connection can be established by soldering, welding, or crimping.

[0040] To contact the contact elements, the center connectors can be passed through one or two openings in the rear protection element. Description of the characters Fig. 1 shows a solar module 1 according to the invention from the front. Fig. 2 shows a solar module 1 according to the invention viewed from its rear side. Fig. 3 shows the first connection box and the second connection box with the contact elements contained therein. Fig. 4 shows a section of a solar module according to the invention in a section at a connection box. Fig. 5 shows a possible division of a solar cell.

[0041] Fig. Figure 1 shows an embodiment of a solar module 1 according to the invention with a first and a second single-row solar cell string 21, 22, as well as a third and a fourth double-row solar cell string 23, 24, which are electrically contacted via the center connectors 31, 32, 33 and 34. The center connectors are arranged in a center region MB of the solar module. The center region MB is a strip-shaped area that extends on both sides of the one-dimensional center line MM. In this embodiment, the solar cell strings consist of series-connected solar partial cells 81, 82, which here are solar half-cells, as shown in Fig. 5. In other embodiments not shown, the solar cells are not divided or are divided into smaller parts than halves. The single-row first solar cell strings 21, 22 are connected in parallel at a first center connector 31 and a second center connector 32 at the end of the respective solar cell string.

[0042] Within the two double-row solar cell strings, namely the third double-row solar cell string 23 and the fourth double-row solar cell string 24, two solar cell substrings are each connected in parallel. In the third solar cell string 23 with a double-row solar cell arrangement, the two solar cell substrings are connected in parallel via the second center connector 32, the first double-row outer connector 321, and the third center connector 33. In the fourth solar cell string 24, the two solar cell substrings are connected in parallel via the third center connector 33, the second outer connector 322, and the fourth center connector 34. The third solar cell string 23 and the fourth solar cell string 24 are electrically connected in series and in series via the third center connector 33. The solar cell substrings consist of solar subcells 81, 82 connected in series.

[0043] Fig. 2 outlines the solar module of the invention by Fig. 1 shows the rear side of the first connection box 51 and the second connection box 52, as well as the bridging elements 41, 42, and 43 arranged in the connection boxes, which are diodes in the illustrated embodiment. The center connectors 31, 32, 33, 34 are electrically connected to contact elements in the connection boxes.

[0044] Fig. Figure 3 shows details of the first and second connection boxes 51, 52 in the presented embodiment. Contact elements 61, 62, 63, 64, 65 are mounted in the connection boxes, each of which is contacted by one of the electrical center connectors 31, 32, 33, or 34. The first contact element 61 and the fifth contact element 65 are also contacted by external connecting lines 91, 92.

[0045] Fig. 4 outlines a section of a detail of the presented embodiment of the solar module according to the invention at the connection box 51 with the center connector 32 and the contact element 62 electrically contacted therewith.

[0046] Fig. 5 outlines the division of a whole pseudo-square solar cell 80 into two solar sub-cells 81, 82 or, in this case, into solar half-cells. Reference symbol 1 solar module 21 First single-row solar cell string 22 Second, single-row solar cell string 23 Third, double-row solar cell string 24 Fourth, double-row solar cell string 31, 32, 33, 34 First, second, third and fourth center connectors 311, 312 First and second outer connectors of single-row solar cell strings 321, 322 First and second outer connectors of two-row solar cell strings 41, 42, 43 Bridging elements 51, 52 First and second connection box 61, 62, 63, 64, 65 First, second, third, fourth and fifth contact elements 71 Front protective element 72 Rear protective element 8 solar cells 81, 82 solar subcells 91, 92 connecting cables MM center line MB midrange QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 202013005357U1

[0008]

Claims

[1] Solar module (1) consisting of several solar cell strings connected in series and in parallel, wherein a first U-shaped, single-row solar cell string (21) is arranged in a first half (A) of the solar module with its starting and end contact pointing towards the module centre, wherein a second, single-row solar cell string (22) is arranged in a second half (B) of the solar module in a mirror image of the first solar cell string, wherein the starting contact of the first solar cell string (21) is connected to a starting contact of the second solar cell string (22) via a first centre connector (31) located in a centre region (MB), wherein the end contacts of the first and second solar cell strings (21, 22) are connected via a second center connector (32) located in the center region (MB) to a starting contact of a third, two-row and U-shaped solar cell string (23) arranged in the first module half (A), wherein the end contact of the third solar cell string (23) is connected to a third center connector (33) arranged in the center region (MB) with the start contact of a fourth, two-row, U-shaped solar cell string (24) arranged in the second module half (B), wherein the end contact of the fourth solar cell string (24) is contacted to a fourth center connector (34) arranged in the center region (MB), and wherein the fourth center connector (34) is arranged at least partially parallel, electrically insulated from each other, next to each other or one above the other to the second center connector (32). [2] Solar module according to claim 1, characterized in that the first center connector (31) is contacted to a first pole of the solar module with a first contact element (61) in a first connection box (51) and the fourth center connector (34) is contacted to a second pole of the solar module with a fifth contact element (65) in a second connection box (52). [3] Solar module according to claim 1 or 2, characterized in that the second center connector (32) is electrically contacted with a second contact element (62) in a first connection box (51) and is electrically contacted with a third contact element (63) in a second connection box (52). [4] Solar module according to claim 1, 2 or 3, characterized in that the third center connector (33) is electrically contacted with a fourth contact element (64) in a second connection box (52). [5] Solar module according to claim 1, 2, 3 or 4, characterized in that a first bridging element (41) located in a first connection box is connected between the first contact element (61) and the second contact element (62), a second bridging element (42) located in a second connection box is connected between the third contact element (63) and the fourth contact element (64) and a third bridging element (43) located in the second connection box is connected between the fourth contact element (64) and the fifth contact element (65). [6] Solar module according to at least one of claims 1 to 5, characterized in that at least one of the center connectors (31, 32, 33, 34) consists of one piece or is composed of several connector parts and is electrically contacted with the contact elements in the connection box. [7] Solar module according to at least one of claims 1 to 6, characterized in that the solar cell strings consist of partial cells connected in series.

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