Method for improving the ohmic contact behavior of a contact grid of a silicon solar cell and apparatus for carrying out the method
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- CE CELL ENG GMBH
- Filing Date
- 2024-07-25
- Publication Date
- 2026-06-03
AI Technical Summary
The existing methods for improving ohmic contact behavior of a silicon solar cell's contact grid are incomplete as they fail to fully illuminate the solar active area due to shading by contact devices, preventing optimal resistance and current flow.
A temporary second contact arrangement is set up after the first contact arrangement, allowing for complete lighting of the solar active side by adjusting the voltage direction via the first and second contact devices, ensuring full illumination and improved ohmic contact behavior.
This approach enables complete lighting of the solar active area, enhancing the ohmic contact behavior of the contact grid by allowing current flow across the entire illuminated surface, achieving optimal resistance and improved performance.
Smart Images
Figure DE2024100663_30012025_PF_FP_ABST
Abstract
Description
Method for improving the ohmic contact behavior of a contact grid of a silicon solar cell and device for carrying out the method
[0001] The invention relates to a method for improving the ohmic contact behavior of a contact grid of a silicon solar cell. The silicon solar cell is first provided with the contact grid, and the contact grid is contacted with a first contacting device electrically connected to a pole of a voltage source. A voltage directed counter to the forward direction of the silicon solar cell, which voltage is lower in magnitude than the breakdown voltage of the silicon solar cell, is applied with the voltage source. Upon application of this voltage, a point light source is guided over a solar-active region of the silicon solar cell. Furthermore, the invention relates to a device for carrying out the method.
[0002] In the prior art, DE 10 2018 001 057.1 proposes a method for improving the ohmic contact behavior of a contact grid of a silicon solar cell. Here, the front and back of the silicon solar cell are electrically biased against their forward direction. The electrically biased silicon solar cell is then scanned (at least in sections) on its solar-active region with a point light source. This induces a current flow, with this current flow having a current density of 200 A / cm² relative to the illuminated section. 2 up to 20,000 A / cm 2and acts on the partial area for 10 ns to 10 ms. This process compensates for faulty processing during the firing of the metal paste, so that the solar cells still achieve the optimal series resistance for their construction. To apply the voltage directed counter to its forward direction, the front of the silicon solar cell is electrically connected to one pole of a voltage source via a first contacting device, and the back of the silicon solar cell is electrically connected to the other pole of the voltage source via a second contacting device.
[0003] Such contacting devices typically have contact pins or contact bars located on the front or back of the silicon solar cell. Silicon solar cells have a contact grid with contact fingers on the front and busbars connecting these contact fingers. In the case of a monofacial silicon solar cell, the back is usually fully metallized. In the case of a bifacial silicon solar cell, contact fingers and busbars connecting these contact fingers are also formed on the back. Preferably, the contact pins or contact bars are positioned on the busbars. Since the busbars are usually not located at the edge of a silicon solar cell, the respective contact device partially shades the solar-active surface of the silicon solar cell. This results in certain areas being inaccessible when scanning the silicon solar cell with the point light source. This, in turn, prevents the ohmic contact behavior of the contact grid of the silicon solar cell from being improved across the entire surface.
[0004] The object of the invention is to further develop the method for improving the ohmic contact behavior of a contact grid of a silicon solar cell in such a way that complete illumination of the silicon solar cell is possible when scanning with the point light source.
[0005] This object is achieved by the methods having the features of claims 1 and 6. Advantageous embodiments of the method can be found in subclaims 2 to 5 and 7 to 9. Furthermore, the object is achieved by a device having the features of claim 10. Advantageous embodiments of the device can be found in subclaims 11 to 13.
[0006] According to the invention, a temporally staggered placement of the second contact arrangement after the first contact arrangement is provided. The first contact arrangement is already located on the contact grid before the second contact arrangement. This enables illumination of the second area, which will later be contacted by the second contact arrangement, wherein the voltage provided for the current flow and directed counter to the forward direction of the silicon solar cell is applied via the first contact arrangement. The illumination of the first area, which is shaded by the first contact arrangement, is then possible when the first contact arrangement is removed while the second contact arrangement is resting on the contact grid. The voltage provided for the current flow and directed counter to the forward direction of the silicon solar cell is then provided via the second contact arrangement.As a result, complete illumination of the solar-active side of the silicon solar cell is possible and thus a full-surface improvement of the ohmic contact behavior of the contact grid of the silicon solar cell can be achieved.
[0007] Exemplary embodiments of the invention are explained below with reference to the drawings. They show: Fig. 1a is a plan view of an embodiment of a device according to the invention for improving the ohmic contact behavior of a contact grid on a front side of a silicon solar cell with a first contact arrangement of a first contacting device placed thereon Fig. 1 b a side view of the device according to Fig. 1a Fig. 1c shows a further plan view of the device according to Fig. 1a with the attached first contact arrangement of the first contacting device and a attached second contact arrangement of the first contacting device Fig. 1d is a further plan view of the device according to Fig. 1a with the first contact arrangement of the first contacting device lifted off and the second contact arrangement of the first contacting device placed on top Fig. 2a a side view of a further embodiment of a device according to the invention for improving the ohmic contact behavior of a first contact grid on a front side of a bifacial silicon solar cell and / or a second contact grid on a rear side of a bifacial silicon solar cell with a mounted first contact arrangement of a first contacting device and a mounted first contact arrangement of a second contacting device Fig. 2b a side view of the device according to Fig. 2a with the attached first contact arrangements, an attached second contact arrangement of the first contacting device and an attached second contact arrangement of the second contacting device Fig. 2c a side view of the device according to Fig. 2a with the second contact arrangements attached and the first contact arrangement lifted off Fig. 3a, side views of a further embodiment of the device according to the invention Fig. 3b for improving the ohmic contact behavior of a first contact grid on a front side of a silicon solar cell Fig. 4a, side views of a further embodiment of the device according to the invention Fig. 4b for improving the ohmic contact behavior of a first contact grid on a front side of a silicon solar cell
[0008] Fig. 1a shows a plan view of a device 1 according to the invention for improving the ohmic contact behavior of a contact grid on a front side 2a of a monofacial silicon solar cell. The device 1 has a first contacting device 4, a second contacting device 5, a voltage source, and a point light source 3. The first contacting device 4 is electrically connected to one pole of a voltage source, and the second contacting device 5 is electrically connected to the other pole of the voltage source. The voltage source is not shown in the illustration. The voltage source is designed such that a voltage directed counter to the forward direction of the silicon solar cell 2, which voltage is lower in magnitude than the breakdown voltage of the silicon solar cell, can be applied via the two contacting devices.Furthermore, the point light source 3 is designed such that, when the voltage directed counter to the forward direction of the silicon solar cell 2 is applied, it can be guided over a solar-active region of the front side 2a of the silicon solar cell 2. Advantageously, the point light source 3 is a laser that can be guided over the solar-active region of the front side 2a of the silicon solar cell 2, for example, by means of a movable mirror. However, the invention is not limited to this. Likewise, the point light source 3 is not limited to a laser. For example, the point light source 3 can also be a focused white light source.
[0009] In the illustration in Fig. 1a, the front side 2a of the silicon solar cell 2 is visible, although the contact grid on the front side 2a is not shown. A rear side 2b of the silicon solar cell 2 is not visible in the illustration. The rear side 2b of a monofacial silicon solar cell 2 is usually metallized over its entire area and forms the rear electrical contact of the silicon solar cell. In the embodiment shown, the second contacting device 5 is formed by two contact bars that bear against the rear side 2b of the silicon solar cell 2. For this purpose, the contact bars can be brought against the rear side 2b of the silicon solar cell 2 or the silicon solar cell 2 can be brought with its rear side 2b against the contact bars. Secure contact of the contact bars against the rear side 2b of the silicon solar cell 2 is advantageously supported by suction between the contact bars and the rear side 2b of the silicon solar cell 2.
[0010] The first contacting device 4 is designed to contact the contact grid on the front side 2a of the silicon solar cell 2. For this purpose, the first contacting device 4 has a first contact arrangement 4a and a second contact arrangement 4b.
[0011] After the silicon solar cell 2 has been provided on the device 1, the first contact arrangement 4a is placed on a contact grid section of a first region 6a of the front side 2a. Likewise, before, during, or after the first contact arrangement is placed, the second contacting device 5 is placed on the rear side 2b of the silicon solar cell 2. After contacting the rear side 2b and contacting the contact grid section of the first region 6a of the front side 2a, the voltage directed counter to the forward direction of the silicon solar cell 2 is then provided by the voltage source, and the point light source 3 is subsequently guided over a second region of the front side 2a located outside the first region 6a. In the illustration, the path 7 of the light beam 8 emitted by the point light source 3 (Fig. 1b) on the front side 2a is shown as a dashed line.This is one possible path 7 of the point light source 3 on the second region of the front side 2a, without the invention being limited thereto. In principle, other paths 7 of the point light source 3 on the second region of the silicon solar cell 2 are also possible. When the light beam emitted by the point light source 3 is guided over the second region of the front side 2a of the silicon solar cell 2, a current flow is induced in the silicon solar cell 2 and in particular in the illuminated region of the silicon solar cell 2, which leads to an improvement in the ohmic contact behavior of the contact grid on the front side 2a of the monofacial silicon solar cell 2 (in particular in the illuminated region). Currents with a current intensity in the range of 1,000 A / cm are typically used. 2 up to 200,000 A / cm 2 relative to the illuminated area.
[0012] Fig. 1 b shows a side view of the device 1 according to Fig. 1 a. This illustration also shows the point light source 3, which is configured as a laser. The light beam 8 emitted by the point light source 3 is shown as a dashed line, with the position of the light beam 8 representing a snapshot.
[0013] The first contact arrangement 4a of the first contacting device 4 and the second contact arrangement 4b of the first contacting device 4 are designed as lever arms with electrically conductive contact pads, which can be placed on the associated contact grid section of the contact grid on the front side 2a of the silicon solar cell 2 by tilting the respective lever arm. In the process state shown, the first contact arrangement 4a is placed on the contact grid section of the first region 6a of the front side 2a of the silicon solar cell 2. The second contact arrangement 4b is lifted off the contact grid section of the second region 6b of the front side 2a of the silicon solar cell 2. Thus, the second region 6b of the front side 2a is in this state separated from the second contact arrangement 4b is not shaded and can therefore be illuminated by the point light source 3.
[0014] The two contact bars of the second contacting device 5 are integrated in a suction table, wherein for contacting the rear side 2b, this suction table with the contact bars is brought to the rear side 2b of the silicon solar cell 2 or the silicon solar cell 2 with its rear side 2b is brought to the suction table.
[0015] The voltage source of the device 1 is also not shown in the illustration according to Fig. 1 b.
[0016] Fig. 1c shows a further top view of the device 1 according to Fig. 1a after the illumination of the second region 6b of the front side 2a of the silicon solar cell. In addition to the first contact arrangement 4a of the first contacting device 4, the second contact arrangement 4b of the first contacting device 4 has now also contacted a contact grid section of the contact grid on the front side 2a of the silicon solar cell 2. For this purpose, the second contact arrangement 4b is placed on the contact grid section of the second region 6b of the front side 2a. After the second contact arrangement 4b has been placed, the point light source 3 is now guided over a third region 6c of the front side 2a located outside the first and second regions 6b.In this case, too, a current flow is induced in the silicon solar cell 2 and in particular in the illuminated area of the silicon solar cell 2, which leads to an improvement in the ohmic contact behavior of the contact grid on the front side 2a of the monofacial silicon solar cell 2 (in particular in the illuminated area).
[0017] Fig. 1d shows a further top view of the device 1 according to Fig. 1a after illuminating the third region 6c of the front side 2a of the silicon solar cell. The first contact arrangement is lifted from the contact grid section of the first region 6a of the front side 2a. The second contact arrangement 4b of the first contacting device 4 is still seated on the contact grid section of the second region 6b of the front side 2a. During this contacting of the contact grid, the point light source 3 is now guided over the first region 6a of the front side 2a.
[0018] To place the first contact arrangement 4a of the first contacting device 4 onto the contact grid on the front side 2, the lever arm of the first contact arrangement 4a is pivoted downwards. To remove the first contact arrangement 4a of the first To detach the contact device 4 from the contact grid on the front side 2, the lever arm of the first contact arrangement 4a is pivoted upward. To place the second contact arrangement 4b of the first contact device 4 onto the contact grid on the front side 2, the lever arm of the second contact arrangement 4b is pivoted downward. To remove the second contact arrangement 4b of the first contact device 4 from the contact grid on the front side 2, the lever arm of the second contact arrangement 4b is pivoted upward.
[0019] The previously described device 1 and the previously described method are equally applicable to a bifacial silicon solar cell 2. Instead of a flat back contact, bifacial silicon solar cells have a back contact that is also designed as a contact grid and thus have a first contact grid on the front side 2a and a second contact grid on the back side 2b. This results in solar-active regions on both the front side 2a and the back side 2b of a bifacial silicon solar cell 2.A bifacial silicon solar cell 2 can now be inserted into the previously described device 1 in such a way that either the first contact grid of the front side 2a is contacted by the first contacting device 4 and the second contact grid of the rear side 2b is contacted by the second contacting device 5, or the first contact grid of the front side 2a is contacted by the second contacting device 5 and the second contact grid of the rear side 2b is contacted by the first contacting device 4. Accordingly, in the first case, the front side 2a of the bifacial silicon solar cell 2 is illuminated with the point light source 3, and in the second case, the rear side 2b is illuminated. When processing a bifacial silicon solar cell 2 with the previously described device 1 and the previously described method, an improvement in the ohmic contact behavior of the contact grid on the front side 2a and the contact grid on the rear side 2b is achieved simultaneously.
[0020] Fig. 2a shows a side view of a further embodiment of a device 1 according to the invention for improving the ohmic contact behavior of a first contact grid on a front side 2a of a bifacial silicon solar cell 2 and / or a second contact grid on a rear side 2b of a bifacial silicon solar cell.
[0021] In contrast to the device 1 shown in Fig. 1a, in the embodiment of the device 1 according to the invention shown in Fig. 2a, the second contacting device 5 is now also designed with a first contact arrangement 5a and a second contact arrangement 5b that are movable during illumination, instead of the stationary contact bars. Device 1 is particularly suitable for bifacial silicon solar cells, but can also be used for monofacial silicon solar cells 2.
[0022] According to Fig. 2a, when placing the first contact arrangement 4a of the first contacting device 4 on the contact grid section of the first contact grid of the first region 6a of the front side 2a, a first contact arrangement 5b of the second contacting device 5 is also placed on a contact grid section of the second contact grid of a first region 6a of the rear side 2b and then the second region of the front side 2a of the bifacial silicon solar cell 2 is illuminated with the point light source 3.
[0023] According to Fig. 2b, when placing the second contact arrangement of the first contacting device 4 on the contact grid section of the first contact grid of the second region 6b of the front side 2a, a second contact arrangement 5b of the second contacting device 5 is placed on a contact grid section of the second contact grid of a second region 6b of the rear side 2b and then the third region 6c of the front side 2a of the bifacial silicon solar cell 2 is illuminated with the point light source 3.
[0024] According to Fig. 2c, when the first contact arrangement 4a of the first contacting device 4 is removed from the contact grid section of the first region 6a of the front side 2a, the first contact arrangement 5b of the second contacting device is also removed from the contact grid section of the first region 6a of the rear side 2b, and the first region of the front side 2a of the bifacial silicon solar cell 2 is subsequently illuminated with the point light source 3. However, removing the first contact arrangement 5b of the second contacting device from the contact grid section of the first region 6a of the rear side 2b is not mandatory, provided only the front side 2a of the bifacial silicon solar cell 2 is illuminated.
[0025] In the embodiment according to Fig. 2a to Fig. 2c, as an alternative to illuminating the front side 2a of the bifacial silicon solar cell 2, the rear side 2b of the bifacial silicon solar cell 2 can also be illuminated with the point light source 3. Simultaneous illumination of the front side 2a and the rear side 2b of the bifacial silicon solar cell 2 is also possible, whereby either a further point light source 3 is used for this purpose or, in the case of the already existing point light source 3, the emitted light is split by means of a beam splitter and guided to the front side 2a and rear side 2b via a mirror system. Here, it is advantageous if both the first contact arrangement 4a and the second contact arrangement 4b of the first contacting device 4 as well as the first contact arrangement 5a and the second contact arrangement 5b of the second contacting device 5 can be attached and removed from the first contact grid on the front side 2a or the second contact grid on the back side 2b of the silicon solar cell 2 during illumination in the areas 6a, 6b.
[0026] The first contact arrangement 5a of the second contacting device 5 and the second contact arrangement 5b of the second contacting device 5 are designed as lever arms with electrically conductive contact pads, which can be placed onto the associated contact grid section of the contact grid on the rear side 2b of the silicon solar cell 2 by tilting the respective lever arm. To place the first contact arrangement 5a onto the contact grid on the rear side 2, the lever arm of the first contact arrangement 5a is pivoted downwards. To remove the first contact arrangement 5a from the contact grid on the rear side 2, the lever arm of the first contact arrangement 5a is pivoted upwards. To place the second contact arrangement 5b onto the contact grid on the rear side 2, the lever arm of the second contact arrangement 5b is pivoted downwards.To remove the second contact arrangement 5b from the contact grid on the front side 2, the lever arm of the second contact arrangement 5b is pivoted upwards.
[0027] In the case of contact grids whose contact fingers are connected to one another via busbars, the contact arrangements are preferably placed on these busbars, although the invention is not limited thereto.
[0028] In the embodiment according to Fig. 3a and Fig. 3b, the device 1 for improving the ohmic contact behavior of a contact grid on a front side 2a of a silicon solar cell comprises the first contacting device 4, the second contacting device 5, the voltage source, and the point light source 3. The first contacting device 4 is electrically connected to one pole of a voltage source, and the second contacting device 5 is electrically connected to the other pole of the voltage source. The first contacting device 4 is designed to contact the contact grid, and the second contacting device 5 is designed to contact the back contact of the silicon solar cell 2. The voltage source is designed to apply a voltage that is directed counter to the forward direction of the silicon solar cell 2, wherein the voltage is lower in magnitude than the breakdown voltage of the silicon solar cell.The point light source 3 is designed to be guided over a solar-active region of the front side 2a of the silicon solar cell 2 when the voltage is applied counter to the forward direction of the silicon solar cell 2. The first. Contacting device 4 has a first contact arrangement 4a and a second contact arrangement 4b. The first contact arrangement 4a is configured such that it can be placed on and removed from a contact grid section of a first region 6a of the front side 2a. The second contact arrangement 4b is configured such that it can be placed on and removed from a contact grid section of a second region 6b of the front side 2a, which lies outside the first region 6a. The point light source 3 is designed such that it is guided over the second region 6b of the front side 2a while the first contact arrangement 4a is placed on the contact grid section of the first region 6a of the front side 2a and while the second contact arrangement 4b is removed from the contact grid section of the second region 6b of the front side 2a.The point light source 3 is further configured to be guided over the first region 6a of the front side 2a while the first contact arrangement 4a is removed from the contact grid section of the first region 6a of the front side 2a and while the second contact arrangement 4b is placed on the contact grid section of the second region 6b of the front side 2a.
[0029] In the illustrated embodiment, the second contacting device 5 is formed by two contact strips that rest against the rear side 2b of the silicon solar cell 2. For this purpose, the contact bars can be brought up to the rear side 2b of the silicon solar cell 2, or the rear side 2b of the silicon solar cell 2 can be brought up to the contact bars. Advantageously, the secure contact of the contact bars with the rear side 2b of the silicon solar cell 2 is supported by suction between the contact bars and the rear side 2b of the silicon solar cell 2. The first contact arrangement 4a of the first contacting device 4 and the second contact arrangement 4b of the first contacting device 4 are designed analogously to the embodiment according to Fig. 1b.
[0030] To contact the contact grid with the first contacting device 4, the first contact arrangement 4a of the first contacting device 4 is first placed onto a contact grid section of the first region 6a of the front side 2a, and after applying the voltage directed counter to the forward direction of the silicon solar cell 2, the point light source 3 is first guided over the second region 6b of the front side 2a, which lies outside the first region 6a. Subsequently, the second contact arrangement 4b of the first contacting device 4 is placed onto the contact grid section of the second region 6b of the front side 2a, and the point light source 3 is guided over the first region of the front side 2a, while the first contact arrangement 4a of the first contacting device 4 is removed from the contact grid section of the first region 6a of the front side 2a.
[0031] In contrast to the embodiment shown in Fig. 3a and Fig. 3b, the embodiment according to Fig. 3a and Fig. 3b has a modified second contacting device 5. The second contacting device 5 has a first contact arrangement 5a and a second contact arrangement 5b. The first contact arrangement 5a of the second contacting device 5 is designed to be deposited on a contact grid section of the first region 6a of the rear side 2b when the first contact arrangement 4a of the first contacting device 4 is deposited on the contact grid section of the first region 6a of the front side 2a. The first contact arrangement 5a of the second contacting device 5 is designed to be removed from the contact grid section of the first region 6a of the rear side 2b when the first contact arrangement 4a of the first contacting device 4 is removed from the contact grid section of the first region 6a of the front side 2a.The second contact arrangement 5b of the second contacting device 5 is designed such that it is deposited on a contact grid section of the second region 6b of the rear side 2b when the second contact arrangement 4b of the first contacting device 4 is arranged on the contact grid section of the second region 6b of the front side 2a. The second contact arrangement 5b of the second contacting device 5 is designed such that it is removed from the contact grid section of the second region 6b of the rear side 2b when the second contact arrangement 4b of the first contacting device 4 is removed from the contact grid section of the second region 6b of the front side 2a.
[0032] In addition to the method described in Fig. 3a and Fig. 3b, the method shown in Fig. 4a and Fig. 4b also comprises the following steps. When the first contact arrangement 4a of the first contacting device 4 is placed on the contact grid section of the first contact grid of the first region 6a of the front side 2a, the first contact arrangement 5b of the second contacting device 5 is placed on a contact grid section of the second contact grid of a first region 6a of the rear side 2b. When the second contact arrangement of the first contacting device 4 is placed on the contact grid section of the first contact grid of the second region 6b of the front side 2a, the second contact arrangement 5b of the second contacting device 5 is placed on a contact grid section of the second contact grid of the second region 6b of the rear side 2b.When the first contact arrangement 4a of the first contacting device 4 is removed from the contact grid section of the first region 6a of the front side 2a, the first contact arrangement 5b of the second contacting device is also removed from the contact grid section of the first region 6a of the rear side 2b. The first contact arrangement 4a of the first contacting device 4, the. second contact arrangement 4b of the first contacting device 4, the first contact arrangement 5a of the second contacting device 5 and the second contact arrangement 5b of the second contacting device 5 are designed analogously to the embodiment according to Fig. 2a.
[0033] Preferably, in the described embodiments, the first contact arrangement 4a of the first contacting device 4 and / or the second contact arrangement 4b of the first contacting device 4 and / or the first contact arrangement 5b of the second Contacting device 5 and / or the second contact arrangement 5b of the second Contacting device 5 can be moved electromotively or pneumatically relative to the silicon solar cell 2, so that the entire process can be automated. List of reference symbols 1 device 2 silicon solar cells 2a front 2b back 3 point light source 4 first contact device 4a first contact arrangement of the first contacting device 4 4b second contact arrangement of the first contacting device 4 5 second contacting device 5a first contact arrangement of the second contacting device 5 5b second contact arrangement of the second contacting device 5 6a first area 6b second area 6c third area 7 Path of the point light source 3 on the silicon solar cell 1 8 Light beam of the point light source 3
Claims
Patent claims 1. A method for improving the ohmic contact behavior of a first contact grid on a front side (2a) of a monofacial or bifacial silicon solar cell, wherein firstly the silicon solar cell (2) is provided with the first contact grid on the front side (2a) of the silicon solar cell (1) and a back contact on a back side (2b) of the silicon solar cell (1), and wherein the first contact grid is contacted with a first contacting device (4) electrically connected to one pole of a voltage source, and wherein the back contact is contacted with a second contacting device (5) electrically connected to the other pole of the voltage source, and wherein a voltage directed counter to the forward direction of the silicon solar cell (2), which voltage is lower in magnitude than the breakdown voltage of the silicon solar cell,is applied and wherein, when this voltage is applied, a point light source (3) is guided over a solar-active area of the front side (2a) of the silicon solar cell (2), characterized in thatthat, in order to contact the first contact grid with the first contacting device (4), first a first contact arrangement (4a) of the first contacting device (4) is placed on a section of the first contact grid in a first region (6a) of the front side (2a), and after the application of the voltage directed counter to the forward direction of the silicon solar cell (2), first the point light source (3) is guided over a second region (6b) of the front side (2a) located outside the first region (6a), and then a second contact arrangement (4b) of the first contacting device (4) is placed on a section of the first contact grid in the second region (6b) of the front side (2a), and the point light source (3) is guided over the first region (6a) of the front side (2a) after the first contact arrangement (4a) of the first contacting device (4) has been removed from the section of the first contact grid in the first region (6a) of the front side (2a).
2. Method according to claim 1, characterized in that the point light source (3) is guided over a third region (6c) of the front side (2a) which lies outside the first region (6b) and the second region (6b) after the point light source (3) has been guided over the first region of the front side (2a) and before the first contacting arrangement (4a) of the first contacting device (4) has been removed from the contact grid section of the first region (6a) of the front side (2a).
3. Method according to claim 1 or 2, characterized in that in the case of a bifacial solar cell, the back contact on the back side (2b) of the silicon solar cell (1) is a second contact grid.
4. Method according to claim 3, characterized in that when placing the first contact arrangement (4a) of the first contacting device (4) on the section of the first contact grid of the front side (2a) in the first region (6a), a first contact arrangement (5b) of the second contacting device (5) is placed on a section of the second contact grid of the rear side (2b) in the first region (6a), and in that when placing the second contact arrangement (4b) of the first contacting device (4) on the section of the first contact grid of the front side (2a) in the second region (6b), a second contact arrangement (5b) of the second contacting device (5) is placed on a section of the second contact grid of the rear side (2b) in the second region (6b).
5. Method according to claim 4, characterized in that when removing the first contact arrangement (4a) of the first contacting device (4) from the section of the first contact grid of the front side (2a) in the first region (6a), the first contact arrangement (5b) of the second contact device is also removed from the section of the second contact grid of the rear side (2b) in the first region (6a).
6. A method for improving the ohmic contact behavior of a first contact grid on a front side (2a) of a bifacial silicon solar cell (2) and / or a second contact grid on a rear side (2b) of a bifacial silicon solar cell, wherein the silicon solar cell (2) is first provided with the two contact grids and wherein the first contact grid is contacted with a first contacting device (4) electrically connected to one pole of a voltage source and wherein the second contact grid is contacted with a second contacting device (5) electrically connected to the other pole of the voltage source and wherein a voltage directed counter to the forward direction of the silicon solar cell (2) and having a magnitude lower than the breakdown voltage of the silicon solar cell is applied with the voltage source, characterized in thatthat for contacting the second contact grid with the second contacting device (5), first a first contact arrangement (5b) of the second contacting device (5) is placed on a section of the second contact grid in a first region (6a) of the rear side (2b) and after applying the opposite to the forward direction of the silicon solar cell, (2) directed voltage, the point light source (3) is first guided over a second region (6b) of the rear side (2b) lying outside the first region (6a), and then a second contact arrangement (5b) of the second contacting device (5) is placed on a section of the second contact grid of the rear side (2b) in the second region (6b), and then the point light source (3) is guided over the first region of the rear side (2b) of the silicon solar cell (2), while the first contact arrangement (5b) of the second contacting device (5) is removed from the section of the second contact grid of the rear side (2b) in the first region (6a).
7. Method according to claim 6, characterized in that after guiding the point light source (3) over the first region of the rear side (2b) and before removing the first contact arrangement (5a) of the second contacting device (5) from the section of the second contact grid in the first region (6a) of the rear side (2b), the point light source (3) is guided over a third region (6c) of the rear side (2b) lying outside the first and second regions (6b).
8. The method according to claim 7, characterized in that when placing the first contact arrangement (5b) of the second contacting device (5) on the section of the second contact grid in the first region (6a) of the rear side (2b), a first contact arrangement (4a) of the first contacting device (4) is placed on a section of the first contact grid of the front side (2a) in the first region (6a), and in that when placing the second contact arrangement (5b) of the second contacting device (5) on the section of the second contact grid of the rear side (2b) in the second region (6b), a second contact arrangement (4b) of the first contacting device (4) is placed on a section of the first contact grid of the front side (2a) in the second region (6b).
9. Method according to claim 8, characterized in that when removing the first contact arrangement (5b) of the second contacting device (5) from the section of the second contact grid of the rear side (2b) in the first region (6a), the first contact arrangement (4a) of the first contact device is also removed from the section of the first contact grid of the front side (2a) in the first region (6a).
10. Device (1) for improving the ohmic contact behavior of a contact grid on a front side (2a) of a silicon solar cell, wherein the device (1) comprises a first contacting device (4), a second contacting device (5), a Voltage source and a point light source (3), wherein the first contacting device (4) is electrically connected to one pole of a voltage source and wherein the second contacting device (5) is electrically connected to the other pole of the voltage source and wherein the first contacting device (4) is designed to contact the contact grid and the second contacting device (5) is designed to contact a back contact of the silicon solar cell (2) and wherein the voltage source is designed to apply a voltage directed counter to the forward direction of the silicon solar cell (2), which voltage is lower in magnitude than the breakdown voltage of the silicon solar cell, and wherein the point light source (3) is designed to be guided over a solar-active region of the front side (2a) of the silicon solar cell (2) when the voltage directed counter to the forward direction of the silicon solar cell (2) is applied, characterized inthat the first contacting device (4) has a first contact arrangement (4a) and a second contact arrangement (4b), and that the first contact arrangement (4a) can be placed on a section of the contact grid in a first region (6a) of the front side (2a) and can be removed from this section, and that the second contact arrangement (4b) can be placed on a section of the contact grid in a second region (6b) of the front side (2a) and can be removed from this section, and that the point light source (3) can be guided over the second region (6b) of the front side (2a) when the first contact arrangement (4a) of the first contacting device (4) is placed on the section of the contact grid in the first region (6a) of the front side (2a) and the second contact arrangement (4b) is removed from the section of the contact grid in the second region (6b) of the front side (2a), and that the point light source (3) can be guided over the first region (6a) of the front side (2a),when the first contact arrangement (4a) of the first contacting device (4) is removed from the section of the first area (6a) of the front side (2a) and the second contact arrangement (4b) of the first contacting device (4) is placed on the contact grid section of the second area (6b) of the front side (2a).
11. Device (1) according to claim 10, characterized in that the point light source (3) is designed to be guided over a third region (6c) of the front side (2a), while the first contact arrangement (4a) is arranged on the section of the contact grid in the first region (6a) of the front side (2a) and the second contact arrangement (4b) is arranged on the section of the contact grid in the second region (6b) of the front side (2a).
12. Device (1) according to claim 10 or 11, characterized in that the second contacting device (5) has a first contact arrangement (5a) and a second contact arrangement (5b), and in that the first contact arrangement (5a) of the second contacting device (5) is designed to be placed on a section of the rear side (2b) in the first region (6a) when the first contact arrangement (4a) of the first contacting device (4) is placed on the section of the contact grid of the front side (2a) in the first region (6a), and in that the first contact arrangement (5a) of the second contacting device (5) is designed to be removed from the section of the rear side (2b) in the first region (6a) when the first contact arrangement (4a) of the first contacting device (4) is removed from the section of the contact grid of the front side (2a) in the first region (6a),and that the second contact arrangement (5b) of the second contacting device (5) is designed to be placed on a section of the rear side (2b) in the second region (6b) when the second contact arrangement (4b) of the first contacting device (4) is placed on the section of the contact grid of the front side (2a) in the second region (6b), and that the second contact arrangement (5b) of the second contacting device (5) is designed to be removed from the section of the rear side (2b) in the second region (6b) when the second contact arrangement (4b) of the first contacting device (4) is removed from the section of the contact grid in the second region (6b).
13. Device (1) according to one of claims 10 to 12, characterized in that the first contact arrangement (4a) of the first contacting device (4) and / or the second contact arrangement (4b) of the first contacting device (4) and / or the first contact arrangement (5b) of the second contacting device (5) and / or the second contact arrangement (5b) of the second contacting device (5) are movable electromotively or pneumatically relative to the silicon solar cell (2).