Solar cell module

Abstract

This solar cell module is provided with: a tab line (41) composed of a collector wiring part (411) provided parallel to each bus bar electrode (22) of a solar cell string (2) in plan view, and an extraction wiring part (412) that branches from the collector wiring part (411) in an intersecting direction and guides a current to the outside of the module, the collector wiring part (411) and the extraction wiring part (412) being integrated in a substantially T-shape in plan view; and connection wiring (42) composed of a bus bar corresponding part (421) which connects each bus bar electrode (22) and each collector wiring part (411), is disposed along the bus bar electrode (22), and is bonded to the bus bar electrode (22) so as to overlap the same in the upper-lower direction, a tab line corresponding part (422) which is disposed along each collector wiring part (411) and is bonded to the bus bar electrode (22) so as to overlap the same in the upper-lower direction, and a connecting part (423) connecting the bus bar corresponding part (421) and the tab line corresponding part (422), the bus bar corresponding part (421), the tab line corresponding part (422), and the connecting part (423) being integrated. In a region (A) including the branch position of the extraction wiring part (412) from the collector wiring part (411) in each tab line (41), the collector wiring part (411) and the tab line corresponding part (422) are not bonded.

Description

Solar cell module Cross-reference to related applications

[0001] The present application claims priority based on Japanese Patent Application No. 2025-055781, which is incorporated into the description of the present application by reference.

[0002] The present invention relates to a solar cell module configured by encapsulating a plurality of solar cells, and a method for manufacturing the same.

[0003] Conventionally, since solar cell modules output power at a design voltage per system unit, a string structure that forms a solar cell string by mutually connecting busbar electrodes of a plurality of solar cells is employed. Ladder wiring (wiring having a ladder-like shape in plan view) is attached to the busbar electrodes of the solar cell string in this string structure, this ladder wiring is further connected to a tab wire which is a wiring for extracting power to the outside, and the end of the tab wire is led to a terminal box for external connection (see Patent Document 1). In this solar cell module, encapsulation needs to be performed by a laminating step of heating and softening an encapsulant made of a thermoplastic resin.

[0004] Japanese Unexamined Patent Application Publication No. 2023-135212

[0005] In this laminating step, softening of the encapsulant causes flow of the resin constituting the encapsulant. The tab wire may be displaced under the stress during this flow. If this displacement is transmitted to the ladder wiring, and the ladder wiring is displaced and distorted relative to the solar cell string, a part of the busbar electrode may be exposed. The exposed state is, for example, a state where a part of the busbar electrode appears in an elongated triangular shape, and the apparent width of the busbar electrode looks as if it has suddenly expanded only in a part thereof. When this occurs, a part of the busbar electrode (which generally exhibits a silver color) becomes visible from outside the module, resulting in poor appearance, which may impair the external appearance of the module. In particular, when at least the appearance-exposed portion of the ladder wiring is colored in a dark color such as black, the visible busbar electrode becomes very conspicuous in appearance due to the contrast in color or brightness.

[0006] The present invention aims to provide a solar cell module that is less susceptible to damage in appearance.

[0007] The solar cell module of the present invention comprises a solar cell string formed by arranging a plurality of solar cells and having busbar electrodes at each end, a sealing material arranged on the front and back sides of the solar cell string, a current collection wiring section provided parallel to each busbar electrode in a plan view, and an extraction wiring section that branches from the current collection wiring section in a cross direction and leads current to the outside of the module through the back side of the solar cell string, and a tab wire in which the current collection wiring section and the extraction wiring section are integrated in a substantially T-shape in a plan view, and a connecting wiring that connects each busbar electrode and each current collection wiring section, wherein each busbar A solar cell module comprising: a busbar corresponding portion arranged along the electrodes and bonded to each busbar electrode so as to overlap in the front-back direction; a tab wire corresponding portion arranged along each current collection wiring portion and bonded to each busbar electrode so as to overlap in the front-back direction; and a connecting portion connecting the busbar corresponding portion and the tab wire corresponding portion, wherein the busbar corresponding portion, the tab wire corresponding portion and the connecting portion are integrated into a single connecting wiring; wherein in the region of each tab wire including the branching position of the extraction wiring portion from the current collection wiring portion, the current collection wiring portion and the tab wire corresponding portion are not bonded.

[0008] Furthermore, the connecting wiring may have a ladder-like shape in plan view, with one busbar-compatible portion and one tab-wire-compatible portion connected by a plurality of connecting portions.

[0009] Figure 1 is a plan view showing a part of the configuration of a solar cell module according to this embodiment. Figure 2 is a schematic cross-sectional view showing the configuration of the solar cell module in the front and back directions (the front (light-receiving surface) side is shown downwards, and the back side is shown upwards). Figure 3 is a plan view showing the ladder wiring used in the solar cell module as a single unit. Figure 4 is an enlarged view of the area enclosed by IV in Figure 1.

[0010] The embodiments of the present invention will be described below with reference to Figures 1 to 4.

[0011] As shown in Figures 1 and 2, the solar cell module 1 mainly consists of solar cell strings 2, a protective plate 3, a sealing material S, and wiring material 4. The sealing material S (light-receiving side sealing material S1, back side sealing material S2) is indicated by its position in Figures 2 and 4.

[0012] The solar cell string 2 is formed by arranging multiple solar cells 21...21 side by side. In this embodiment, each solar cell 21 is strip-shaped, with busbar electrodes formed at one end on the surface (light-receiving surface) in the shorter direction and the other end on the back side. Multiple finger electrodes (not shown), narrower than the busbar electrodes, are formed in a direction intersecting each busbar electrode. The front and back busbar electrodes are stacked facing each other and connected by a conductive adhesive paste (silver paste, etc.) to form a "singling connection" that constitutes the solar cell string 2. Therefore, in the solar cell string 2, each end in the direction in which the multiple solar cells 21...21 are arranged (longitudinal direction in this embodiment, vertical direction in Figure 1) has busbar electrodes 22, 22 for extracting power from the solar cell string 2, which are formed on the solar cells 21, 21 located at both ends in the parallel configuration. In the solar cell string 2, the busbar electrode 22 at one end (the upper end in Figure 1) is located on the module surface side, and the busbar electrode 22 at the other end (the lower end in Figure 1) is located on the module back side.

[0013] The protective plate 3 is a plate-shaped portion provided to protect the solar cell string 2 from the external environment of the module. The protective plate 3 is provided so as to sandwich the solar cell string 2 from the front and back sides. As the protective plate 3, a glass plate or a resin sheet (especially when placed on the back side) can be used. The protective plate 3 may be flat or curved. In addition, when the protective plate 3 is curved, adverse effects on the flow of the resin constituting the sealing material during the lamination process are more likely to occur, and therefore the effects of applying the present invention can be expected.

[0014] The sealing material is positioned on both the front and back sides of the solar cell string 2, and is located inward in the module thickness direction from the protective plate 3. In its raw state, the sealing material is a sheet-like body made of thermoplastic resin, and by heating during the lamination process in the manufacturing of the solar cell module, it softens and flows, thereby filling and sealing the gap between the front and back protective plates 3, 3 and the solar cell string 2. The sealing material may also be made of a polymer material, for example, a synthetic resin other than a thermoplastic resin, such as a thermosetting resin.

[0015] The wiring material 4 is made of a conductive material and consists of tab wires 41 and connecting wires 42. The tab wire 41 consists of a current collection wiring section 411 provided parallel to each busbar electrode 22 in a plan view, and an extraction wiring section 412 that branches off from the current collection wiring section 411 in a cross direction and leads current to the outside of the module through the back side of the solar cell string 2. The current collection wiring section 411 and the extraction wiring section 412 are integrally formed in a roughly T-shape in a plan view. As schematically shown in Figure 2, the current collection wiring section 411 and the extraction wiring section 412 are separate wiring materials, and the overlapping portions in the thickness direction are electrically connected to integrate them. The extraction wiring section 412 is usually introduced into a terminal box (not shown) provided on the back side of the solar cell module. Also, as shown in the schematic diagram Figure 2, an insulating sheet 5 made of resin or the like is placed between the solar cell string 2 and the extraction wiring section 412 to insulate them from each other.

[0016] The connecting wiring 42 is wiring that connects each busbar electrode 22 to each current collection wiring section 411. The connecting wiring 42 is attached to one end (upper end in Figure 1) and the other end (lower end in Figure 1) of each solar cell string 2. As shown in Figure 3, the connecting wiring 42 has a busbar corresponding section 421, a tab wire corresponding section 422, and a connecting section 423. The busbar corresponding section 421, the tab wire corresponding section 422, and the connecting section 423 are integrated. For example, solder-coated wiring can be used for the connecting wiring 42. The connecting wiring 42 has a ladder-like shape in plan view, with one busbar corresponding section 421 and one tab wire corresponding section 422 connected by multiple connecting sections 423...423. For this reason, the connecting wiring 42 is sometimes called "ladder wiring". In addition, at least the visible portion of the connecting wiring 42 can be made a dark color that is less conspicuous in relation to the color of the surface (light-receiving surface) of the solar cell 21. In this embodiment, the color is black.

[0017] The busbar-compatible portion 421 is positioned along each busbar electrode 22 and is bonded to each busbar electrode so as to overlap in the front-back direction (conductive bonding using solder or conductive adhesive paste, the same applies hereinafter). The tab wire-compatible portion 422 is positioned along each current collection wiring portion 411 and is bonded to each busbar electrode so as to overlap in the front-back direction with respect to a part of the current collection wiring portion 411 (the lower part in Figure 4). The connecting portion 423 connects the busbar-compatible portion 421 and the tab wire-compatible portion 422. Multiple connecting portions 423...423 are positioned at intervals between the busbar-compatible portion 421 and the tab wire-compatible portion 422. Current can be smoothly passed from the busbar electrode 22 to the tab wire 41 via the connecting wiring 42 having multiple connecting portions 423...423.

[0018] In the solar cell module 1 of this embodiment, in any range within region A (the region enclosed by the horizontally elongated rectangle with a dashed line in Figure 4), which includes the branching position of the output wiring portion 412 from the current collection wiring portion 411 in the tab wire 41, the current collection wiring portion 411 and the tab wire corresponding portion 422 in the connecting wiring (ladder wiring) 42 are not bonded. Outside of region A, the current collection wiring portion 411 and the tab wire corresponding portion 422 are bonded. By providing a portion where the current collection wiring portion 411 and the tab wire corresponding portion 422 are not bonded (non-bonded portion), even if the tab wire 41 is displaced within the module due to the flow of the sealing material during the lamination process in the manufacturing process of the solar cell module, the displacement is less likely to be transmitted to the busbar corresponding portion 421 in the connecting wiring 42. As a result, it is less likely that a portion of the busbar electrode 22 will be visible from outside the module (this occurs when the busbar corresponding portion 421 in the connecting wiring (ladder wiring) 42 moves to a position that does not cover the busbar electrode 22), thus preventing the busbar electrode 22 from being irregularly visible and resulting in the effect of not damaging the appearance of the module.

[0019] Incidentally, even if the countermeasures of this embodiment are taken, misalignment of the tab wire 41 itself will still occur. However, it can be said that misalignment of only the tab wire 41 does not affect the appearance. For example, the following can be given for this reason. That is, in the actual product of the solar cell module 1, a sheet is separately placed to conceal the tab wire 41 in the area where the tab wire 41 is located, so the misalignment of the tab wire 41 is hidden by the sheet and does not affect the appearance. Furthermore, even if the sheet is not placed, the length of the current collection wiring portion 411 in the longitudinal direction of the tab wire 41 is extremely long compared to the misalignment dimension, so the misalignment will be at a level that is not perceptible to the eye, and therefore does not affect the appearance.

[0020] Here, in the tab wire 41, the point where the output wiring section 412 branches off from the current collection wiring section 411 is roughly T-shaped in plan view, and is therefore more susceptible to stress P (indicated by arrows in Figure 4) from the flowing sealing material compared to other parts (straight parts). In this embodiment, by providing a non-adhesive section in this part to prevent the connecting wiring (ladder wiring) 42 from moving along with it, the busbar corresponding section 421 of the connecting wiring 42 can more easily maintain a stationary state relative to the busbar electrode 22, thus leading to the aforementioned effects and benefits.

[0021] The non-adhered portion in region A can be provided in a symmetrical area on Figure 4 in a plan view, with reference to the branching position of the output wiring portion 412 from the current collection wiring portion 411 on the tab wire 41. This makes it easier to balance the transmission of stress P related to preventing misalignment in the extension direction (left-right direction in the figure) of the current collection wiring portion 411 with respect to the action of interrupting the transmission between the tab wire 41 and the connecting wiring (ladder wiring) 42. In this embodiment, the adhesion between the current collection wiring portion 411 and the tab wire corresponding portion 422 outside of region A is performed intermittently in the direction in which the current collection wiring portion 411 extends.

[0022] Although embodiments of the present invention have been described above, the solar cell module 1 of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of one embodiment can be deleted.

[0023] For example, in the solar cell module 1 of the above embodiment, the surface (light-receiving surface) is more visible from the outside, so the non-adhesive portion only needed to be provided on the surface (light-receiving surface). However, it is not limited to this, and the non-adhesive portion may be provided on both the surface (light-receiving surface) and the back surface of the solar cell module 1.

[0024] The configuration and operation of the above embodiment are summarized below. The solar cell module of the present embodiment is formed by arranging a plurality of solar cells 21 and comprising a solar cell string 2 having busbar electrodes 22 at each end, a sealing material S arranged on the front and back sides of the solar cell string 2, a current collection wiring section 411 provided parallel to each busbar electrode 22 in a plan view, and an extraction wiring section 412 that branches from the current collection wiring section 411 in a cross direction and leads current to the outside of the module through the back side of the solar cell string 2, and a tab wire 41 in which the current collection wiring section 411 and the extraction wiring section 412 are integrated in a substantially T shape in a plan view, and a connecting wiring 42 that connects each busbar electrode 22 and each current collection wiring section 411, and each busbar electrode 22 The solar cell module 1 comprises a busbar corresponding portion 421 arranged along the busbar electrode 22 and bonded to each busbar electrode 22 so as to overlap in the front-back direction, a tab wire corresponding portion 422 arranged along the current collection wiring portion 411 and bonded to each current collection wiring portion 411 so as to overlap in the front-back direction, and a connecting portion 423 connecting the busbar corresponding portion 421 and the tab wire corresponding portion 422, and a connecting wiring 42 in which the busbar corresponding portion 421, the tab wire corresponding portion 422 and the connecting portion 423 are integrated, wherein in region A including the branching position of the output wiring portion 412 from the current collection wiring portion 411 in each tab wire 41, the current collection wiring portion 411 and the tab wire corresponding portion 422 are not bonded.

[0025] According to the above configuration, even if the tab wire 41 is displaced due to the flow of the sealing material S during the lamination process in the manufacturing process of the solar cell module 1, the displacement is less likely to be transmitted to the busbar corresponding portion 421 of the connecting wiring 42.

[0026] Furthermore, the connecting wiring 42 may have a ladder-like shape in plan view, with one busbar-compatible portion 421 and one tab wire-compatible portion 422 connected by a plurality of connecting portions 423.

[0027] According to the above configuration, current can be smoothly passed from the busbar electrode 22 to the tab wire 41 via the connecting wiring 42 having a plurality of connecting portions 423.

[0028] As described above, according to the present invention, in the lamination process, the displacement is less likely to be transmitted to the busbar corresponding portion 421 of the connecting wiring 42, so that a part of the busbar electrode 22 is less likely to be visible from outside the module, and thus the appearance of the module is less likely to be damaged.

[0029] 1...Solar cell module, 2...Solar cell string, 3...Protective plate, 4...Wiring material, 5...Insulating sheet, 21...Solar cell, 22...Busbar electrode, 41...Tab wire, 42...Connecting wiring, 411...Current collection wiring section, 412...Output wiring section, 421...Busbar corresponding section, 422...Tab wire corresponding section, 423...Connecting section, A...Region including branching position in tab wire, P...Stress from sealing material, S...Sealing material, S1...Sealing material on the light-receiving surface side, S2...Sealing material on the back side S2

Claims

1. A solar cell string formed by arranging multiple solar cells and having busbar electrodes at each end; a sealing material disposed on the front and back sides of the solar cell string; a tab wire comprising a current collection wiring section provided parallel to each busbar electrode in a plan view, and an extraction wiring section branching from the current collection wiring section in a cross direction and passing through the back side of the solar cell string to guide current to the outside of the module, wherein the current collection wiring section and the extraction wiring section are integrated in a substantially T-shape in a plan view; and a connecting wiring that connects each busbar electrode and each current collection wiring section, comprising a busbar corresponding section arranged along each busbar electrode and bonded to each busbar electrode so as to overlap in the front-back direction; a tab wire corresponding section arranged along each current collection wiring section and bonded to each current collection wiring section so as to overlap in the front-back direction; and a connecting section connecting the busbar corresponding section and the tab wire corresponding section, wherein the busbar corresponding section, the tab wire corresponding section and the connecting section are integrated into a single connecting wiring; A solar cell module in which, in the region including the branching position of the output wiring portion from the current collection wiring portion in each tab wire, the current collection wiring portion and the tab wire corresponding portion are not bonded together.

2. The solar cell module according to claim 1, wherein the connecting wiring has a ladder-like shape in plan view, with a plurality of connecting parts connecting one busbar-corresponding part and one tab-wire-corresponding part.

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