IBC solar module

Abstract

The invention relates to an IBC solar module (10) comprising - a plurality of IBC solar cells (12) connected in series, - wherein the IBC solar module (10) has a front side with an active surface which is designed to absorb solar radiation in the operating state, and a rear side opposite the front side, - a plurality of bridging elements (20) which are each designed to bridge an IBC solar cell (12) in the event of shade or a defect, - wherein for each of the IBC solar cells (12) at least one bridging element (20) is provided which is connected in parallel to the IBC solar cell (12).

Description

[0001] IBC solar module

[0002] The present invention relates to an IBC solar module.

[0003] Solar modules are available in various designs and make a significant contribution to energy generation from renewable energy sources. The widespread use of solar modules can therefore significantly reduce global CO2 emissions.

[0004] One specific type of solar module that has recently gained popularity is the IBC solar module (also known as interdigitated back contact solar module). IBC solar modules consist of multiple IBC solar cells, with electrical contacts located only on the back of the solar cells.

[0005] Typical IBC solar modules consist of several IBC solar cells connected in series. The maximum current flowing through a solar module is limited by the minimum current that can flow through a single solar cell. If one of the solar cells is shaded, the electrical power generated by that cell and the maximum current that can flow through it are reduced. Consequently, the current flowing through the remaining solar cells is also limited, significantly reducing the power generated by the entire solar module if a single solar cell is shaded.

[0006] One approach to reducing the undesirable effect described above is to connect several solar cells in series to form a string (sometimes also called a solar array) and protect the individual strings with bypass elements. Bypass diodes (also called bridging diodes) can be used as these bridging elements, bypassing a string if one or more solar cells within the string are shaded. This prevents the total current flowing through the remaining solar cells from being negatively affected by a single affected solar cell.

[0007] For example, an IBC solar module can have four strings, each comprising six IBC solar cells, with four bypass diodes to bridge individual strings when needed. However, if a single solar cell within a string is shaded, all solar cells within that affected string will no longer contribute to energy generation. In the example above, the output power of the IBC solar module therefore drops by 25% (one out of four strings is bypassed), even though only about 4% of the solar cells (one out of 24) are affected by the shading.

[0008] Based on the disadvantages described above, the object of the present invention is to provide an IBC solar module that enables the most efficient energy generation possible, even in the case of shading of individual solar cells.

[0009] To solve the aforementioned problem, the present invention proposes a shading-resistant IBC solar module comprising the following components: several IBC solar cells connected in series, wherein the IBC solar module has a front side with an active surface designed to absorb solar radiation in the operating state, and a rear side opposite the front side; several bridging elements, each designed to bridge an IBC solar cell in the event of shading or a defect, wherein at least one bridging element is provided for each of the IBC solar cells, which is connected in parallel to the IBC solar cell.

[0010] The IBC solar module according to the invention enables particularly efficient generation of electrical energy, with a reduced power loss in the event of shading of one or more IBC solar cells compared to IBC solar modules known from the prior art. This is achieved by providing a separate bridging element (also referred to as a bypass element) for each of the IBC solar cells. Therefore, if a single solar cell is switched off, this does not affect the electrical energy generated by the remaining solar cells. Thus, if, as in the example described in the introduction, a total of 24 solar cells are present in a solar module and one of these 24 solar cells is switched off, the output power generated by the solar module is reduced by only 1 / 24 (approximately 4%).

[0011] The front of the solar module can also be referred to as the first side, and the back of the solar module can also be referred to as the second side. The bypass elements can be designed, for example, as bypass diodes or transistors. These bypass elements are designed to bypass a solar cell when the current flowing through it falls below a predetermined threshold.

[0012] In the present invention, at least one bridging element can be arranged between two IBC solar cells. By arranging a bridging element in the space between two IBC solar cells, a particularly compact design of the solar module is enabled. This is especially advantageous because the IBC solar module according to the invention uses a larger number of bridging elements compared to the prior art. A further advantage of this embodiment of the invention is that the bridging element is mechanically protected in the space between two IBC solar cells, particularly when the thickness of the bridging element used is less than the thickness of the solar cells.

[0013] In particular, it can be arranged that all bridging elements are positioned between two IBC solar cells. This allows for a compact IBC solar module to be provided despite the relatively high number of bridging elements.

[0014] Furthermore, the present invention may provide that the IBC solar cells are interconnected by electrical conductors and that at least one bridging element is connected via a soldered, adhesive, or welded connection to a conductor section running between two IBC solar cells. Preferably, all bridging elements are connected via a soldered, adhesive, or welded connection to conductor sections of the electrical conductors that run between two IBC solar cells. Preferably, two conductors connect two adjacent solar cells, with the bridging element(s) then being arranged between the two conductors.

[0015] The IBC solar module according to the invention can also be provided with at least one bridging element arranged on the back side of an IBC solar cell. By arranging a bridging element on the back side of an IBC solar cell, this solar cell can be used as a heat sink. This allows the heat generated by the bridging element to be efficiently dissipated, thus cooling the bridging element without additional coolant. In particular, it can be provided that all bridging elements are arranged on the back side of an IBC solar cell. This reduces the circuit complexity and simplifies the assignment of the individual bridging elements to the respective solar cells. At the same time, the required amount of electrical wiring is reduced, thereby lowering manufacturing costs.In some preferred embodiments of the present invention, at least one bridging element may be received in a receiving groove located on the rear side of an IBC solar cell. This simplifies the positioning of the bridging elements and also avoids any mechanical stress on the bridging elements from adjacent layers. This can extend the service life of the IBC solar module. The receiving groove can, in particular, be cuboid in shape so that the bridging element can be inserted into the receiving groove from the rear side of the IBC solar cell.

[0016] Furthermore, in the present invention, it is preferably provided that at least one bridging element is connected to the back side of an IBC solar cell via a soldered connection, an adhesive bond, or a welded connection. In particular, the soldered and welded connections improve heat dissipation from the bridging element to the respective IBC solar cell. This leads to an increased service life of the bridging element and thus of the entire solar module. It is preferably provided that all of the bridging elements are connected to the back side of an IBC solar cell via soldered connections, adhesive bonds, or welded connections.

[0017] Furthermore, the IBC solar module according to the invention may be provided that at least two IBC solar cells are connected to each other by means of busbars (also referred to as current busbars or current collectors) or another type of electrical conductor, and that at least one bridging element is arranged between two busbars or two electrical conductors. The busbars or the electrical conductors may, in particular, be made of copper, aluminum, or an alloy. Preferably, it may be provided that all of the IBC solar cells are connected to each other by means of busbars and that all of the provided bridging elements are arranged between two busbars.

[0018] Furthermore, in the present invention, the IBC solar module can be designed as a laminated solar module, with the bridging elements arranged beneath the laminate. This protects the bridging elements from external influences such as moisture and mechanical stress. Preferably, the bridging elements are arranged between two busbars beneath the laminate.

[0019] According to some preferred embodiments of the present invention, particularly compact or thin bridging elements may be used. The use of compact bridging elements reduces the mechanical stress on the solar cells within the mounted solar module. Furthermore, it allows existing solar module frames to continue to be used and eliminates the need to replace them with new frames.

[0020] In particular, the present invention may provide that the IBC solar module has at least one bridging element configured as a bypass diode or bypass transistor, preferably as a MOSFET (metal-oxide-semiconductor field-effect transistor) or as a thin-film transistor. This allows for particularly compact bridging elements, thereby achieving the advantages of compact design and low mechanical stress on the solar cells described above.

[0021] Preferably, the bridging elements can be implemented as gate-controlled thin-film transistors (also known as TFTs). Thin-film transistors can be manufactured commercially at low costs and, due to their area definition, offer the possibility of directly adjusting the current. Furthermore, thin-film transistors have a lower area density, which allows for particularly compact bridging elements.

[0022] Finally, the present invention may provide for the IBC solar cells to be configured as monofacial or bifacial solar cells. In bifacial solar cells, the solar cells have two active surfaces designed to absorb solar radiation and convert it into electrical energy, whereas monofacial solar cells have only one active surface.

[0023] The present invention will now be explained in more detail with reference to the figures. The figures show

[0024] Fig. 1 shows a first example of a solar module according to the prior art, Fig. 2 shows a second example of a solar module according to the prior art, Fig. 3 shows a first embodiment of an IBC solar module according to the present invention.

[0025] Fig. 4 shows a second embodiment of an IBC solar module according to the present invention, and

[0026] Fig. 5 shows a third embodiment of an IBC solar module according to the present invention.

[0027] Figure 1 schematically illustrates a first example of a solar module 10, as known from the prior art. The solar module 10 comprises several solar cells 12 connected in series. During operation, each solar cell 12 absorbs sunlight, and the absorbed energy is converted into electrical energy. A voltage is generated at each solar cell 12, which sums due to the series connection of the solar cells 12. The solar module 10 has a first terminal 14 and a second terminal 16. A voltage is generated between these two terminals 14 and 16, which corresponds to the sum of the individual voltages at the solar cells 12. The terminals 14 and 16 can either be connected directly to a load or, alternatively, to an inverter, which converts the generated DC voltage into an AC voltage. In the example shown in Figure 1, the solar module 10 has a first terminal 14 and a second terminal 16.The problem arising with the solar module 10 shown in Figure 1 is that the current generated by the solar module 10 is limited, due to the series connection, by the minimum current that can flow through the individual solar cells 12. Therefore, if one of the solar cells 12 is shaded or defective, the current flowing through the other solar cells 12 is also reduced, thus significantly reducing the overall output power of the solar module 10. To address this problem, prior art proposes solar modules 10 as shown in Figure 2 below.

[0028] Figure 2 schematically illustrates a second example of a solar module 10 according to the prior art. The solar module 10 shown in this figure also has several solar cells 12 connected in series. These n solar cells 12 together form a string 18. The solar module 10 shown in Figure 2 has a total of three strings 18. Each string 18 can, for example, have six, eight, ten, or twelve solar cells 12. Each of the strings 18 is protected by a bridging element 20. The bridging element 20 can, for example, be a bridging diode (also called a bypass diode). The bridging elements 20 are usually arranged in a separate terminal box 22.For example, if a solar cell 12 within a string 18 is disconnected or defective, preventing current from flowing through it, the entire affected string 18 is bypassed by the bridging element 20. This offers the advantage that the affected solar cell 12 does not negatively impact the power generation by the solar cells 12 contained in the unaffected strings 18. On the other hand, a solar module 10 according to Fig. 2 has the disadvantage that if a solar cell 12 is shaded, the entire affected string 18 is bypassed, resulting in a loss of approximately 33% of the generated electrical power within the entire solar module 10 in the illustrated embodiment, since one of the three strings 18 can no longer contribute to energy generation.

[0029] Figure 3 schematically illustrates a first embodiment of an IBC solar module 10 according to the present invention. Unlike the prior art, the embodiment shown in Figure 3 provides a bridging element 20 for each solar cell 12. This offers the advantage that, in the case of a shaded or defective solar cell 12, only that single solar cell 12 is bridged by its associated bridging element 20. If a solar module 10 has, for example, 30 solar cells 12, the output power of the solar module 10 exhibits a power loss of only approximately 3% in the case of a shaded or defective solar cell 12 (one of the 30 solar cells is bridged). This significantly reduces the power loss compared to the solar module shown in Figure 2.As shown in the 3 excerpt example, the bridging of solar cells 12 can be limited to those solar cells 12 that are actually affected by shading or a defect, instead of bridging all solar cells 12 within a string.

[0030] Figure 4 schematically illustrates a second embodiment of an IBC solar module 10 according to the present invention. Figure 4(a) shows a side view, Figure 4(b) a rear view, and Figure 4(c) a top view of the IBC solar module 10. As can be seen in Figures 4(a) to (c), the solar cells 12 of the solar module 10 each have a front 24 and a back 26. Electrical conductors are provided on the back 26 of the solar cells 12, which are designed, for example, as connecting tabs 28, and which electrically connect the solar cells 12 to one another. In the embodiment shown in Figures 4(a) to (c), the bridging element 20, which can be designed, in particular, as a bypass diode, is arranged between two solar cells 12. In particular, the bridging element 20 can be connected to the connecting tab 28 via a soldered connection, an adhesive connection or a welded connection.Preferably, the bridging element 20 is arranged between two electrical conductors. One of the electrical conductors may protrude partially from below the solar cell 12. Figures 4(b) and (c) show that an extended connecting tab 30 is provided next to the connecting tab 28, which protrudes a portion from the solar cell 12, with the bridging element 20 arranged between the connecting tab 28 and the extended connecting tab 30. In particular, it is further preferred that the bridging element 20 has a smaller thickness than the solar cells 12. This allows the bridging elements 20 to be integrated into a solar module 10 without increasing the overall thickness of the solar module 10.Furthermore, this ensures that the bridging elements 20 are protected from mechanical influences, as they are integrated into the spaces between each pair of solar cells 12.

[0031] Figure 5 schematically illustrates a third embodiment of an IBC solar module 10 according to the present invention. Figure 5(a) shows a side view, Figure 5(b) a rear view, and Figure 5(c) a top view of the IBC solar module 10. In the embodiment shown in Figures 5(a) to 5(c), the solar module 10 has bridging elements 20 arranged on the rear side 26 of the solar cells 12. In particular, the bridging elements 20 can be arranged on the underside 26 of the solar cells between two electrical conductors designed as busbars or connecting tabs 28. The bridging elements 20 can be connected to the electrical conductors by means of a soldered connection, a welded connection, or an adhesive bond.The arrangement of the bridging elements 20 on the rear side of the solar cells 12 offers the particular advantage that the heat generated in the bridging elements 20 can be dissipated via the solar cells 12, thereby increasing the service life of the bridging elements 20 and consequently also the service life of the entire IBC solar module 10. Furthermore, this arrangement allows the spacing between the individual solar cells to be reduced, enabling a particularly compact solar module. This allows for the production of solar modules with a particularly high efficiency. In this embodiment, the bridging elements 20 can be designed as bypass transistors, preferably as MOSFETs or thin-film transistors. This allows for very compact bridging elements that do not significantly increase the thickness of the entire solar module 10.The use of very thin bridging elements 20 also reduces the mechanical stress on the bridging elements 20 and on the solar cells 12, thereby increasing the service life of the IBC solar module 10.

[0032] REFERENCE MARK LIST

[0033] solar panel

[0034] Solar cell first connection second connection

[0035] String

[0036] bridging element

[0037] Connection box

[0038] Front of a solar cell

[0039] back of a solar cell

[0040] Connecting tab extended connecting tab

Claims

REQUIREMENTS 1. IBC solar module (10) comprising several IBC solar cells (12) connected in series, wherein the IBC solar module (10) has a front side with an active surface designed to absorb solar radiation in the operating state, and a rear side opposite the front side, several bridging elements (20) each designed to bridge an IBC solar cell (12) in the event of shading or a defect, wherein at least one bridging element (20) is provided for each of the IBC solar cells (12) and is connected in parallel to the IBC solar cell (12).

2. IBC solar module (10) according to claim 1, characterized in that at least one bridging element (20) is arranged between two IBC solar cells (12).

3. IBC solar module (10) according to claim 2, characterized in that the IBC solar cells (12) are connected to each other by electrical conductors and that at least one bridging element (20) is connected via a soldered connection, an adhesive connection or a welded connection to a conductor section running between two IBC solar cells (12) of one of the electrical conductors.

4. IBC solar module (10) according to one of claims 1 to 3, characterized in that at least one bridging element (20) is arranged on a rear side (26) of an IBC solar cell (12).

5. IBC solar module (10) according to claim 4, characterized in that at least one bridging element (20) is located in a receiving groove which is mounted on is located on the back (26) of an IBC solar cell (12).

6. IBC solar module (10) according to one of claims 4 or 5, characterized in that at least one bridging element (20) is connected to the back (26) of an IBC solar cell (12) via a soldered connection, an adhesive connection or a welded connection.

7. IBC solar module (10) according to one of claims 1 to 6, characterized in that at least two IBC solar cells (12) are connected to each other by means of busbars and that at least one bridging element (20) is arranged between two busbars.

8. IBC solar module (10) according to one of claims 1 to 7, characterized in that the IBC solar module (10) is designed as a laminated solar module, wherein the bridging elements (20) are arranged below the laminate.

9. IBC solar module (10) according to one of claims 1 to 8, characterized in that the IBC solar module (10) has at least one bridging element (20) which is designed as a bypass diode or bypass transistor, preferably as a MOSFET or as a thin-film transistor.

10. IBC solar module (10) according to one of claims 1 to 9, characterized in that the IBC solar cells (12) are designed as monofacial or bifacial solar cells (12).

Images