Back-contact battery and photovoltaic module

Abstract

The present invention provides a back-contact battery and a photovoltaic module. The back-contact battery includes a battery body having opposite first and second surfaces; a first electrode and a second electrode disposed on the first surface of the battery body, the first electrode and the second electrode are alternately arranged at intervals in a first direction and extend in a second direction; a connecting conductor disposed on the first surface and extending in the first direction, the connecting conductor is connected to one of the first electrode and the second electrode, and an insulating block is provided between the connecting conductor and the other; wherein the connecting conductor includes a first portion disposed on the insulating block and a second portion disposed outside the insulating block, and a first width of the first portion in the second direction is smaller than a second width of the second portion in the second direction.

Description

Technical Field

[0001] At least one embodiment of the present invention relates to the field of photovoltaic technology, and in particular, to a back-contact battery and a photovoltaic module. Background Art

[0002] In a back-contact battery, a positive secondary grid and a negative secondary grid are respectively arranged on different doping regions of the backlight surface of the battery body, and then the current generated by the battery body is collected by connecting to the main grid of the same polarity. In addition to connecting to the secondary grid, the main grid also needs to be connected to an external electrical connector to form a battery string by connecting multiple back-contact batteries in series. Therefore, the connection strength between the main grid and the secondary grid and between the main grid and the electrical connector is of great significance to the reliability of the back-contact battery and the photovoltaic module formed by the back-contact battery.

[0003] Since the main grid and the secondary grid are arranged in different directions, the main grid will cross the secondary grids of different polarities while connecting to the secondary grid of the same polarity. To prevent short circuits caused by the main grid connecting the secondary grids of different polarities, an insulating block needs to be arranged between the main grid and the secondary grids of different polarities. Usually, the connection strength between the main grid and the insulating block is poorer than the connection strength between the main grid and the battery body. Therefore, the reliability of the connection between the main grid and the secondary grid is limited. Summary of the Invention

[0004] To solve at least one of the above and other technical problems in the prior art, the present invention provides a back-contact battery and a photovoltaic module, which are beneficial to improving the reliability of the connection between the connecting conductor and the electrode and the external electrical connector.

[0005] An embodiment of the present invention provides a back-contact battery, including a battery body having opposite first and second surfaces; a first electrode and a second electrode arranged on the first surface of the battery body, the first electrode and the second electrode are alternately arranged at intervals in a first direction in sequence and extend in a second direction perpendicular to the first direction; a connecting conductor arranged on the first surface and extending in the first direction, the connecting conductor is connected to one of the first electrode and the second electrode, and an insulating block is arranged between the connecting conductor and the other; wherein, the connecting conductor includes a first part arranged on the insulating block and a second part arranged outside the insulating block, and a first width of the first part in the second direction is smaller than a second width of the second part in the second direction.

[0006] In the case of adopting the above-described implementation scheme, the wider second part is used to connect to the first electrode or the second electrode. This makes the part of the connecting conductor connecting the electrodes wider in the second direction and have a larger bonding area with the battery body, effectively improving the connection reliability between the connecting conductor and the electrodes; and when the second part is connected to an external electrical connector, since the area of the second part is larger, a bonding part with a larger area can be formed between it and the electrical connector, which is beneficial to improving the tensile force between the connecting conductor and the electrical connector. Moreover, even if the bonding part shifts along the second direction, at least a part of the bonding part can be arranged on the second part to shorten the current collection path and improve the current collection efficiency.

[0007] In some exemplary embodiments, the two ends of the second part along the second direction protrude from the first part, and the part of each end of the second part protruding from the first part has a width between 80 and 250 micrometers along the second direction.

[0008] In some exemplary embodiments, the first width is between 0.5 and 1.5 millimeters.

[0009] In the case of adopting the above-described implementation scheme, when the connecting conductor designed based on the above dimensions is joined to the electrical connector, it is beneficial to increase the specific surface area of the joint part and improve the tensile force between the connecting conductor and the electrical connector.

[0010] In some exemplary embodiments, the battery body has a first side extending along the second direction, the connecting conductor includes a first connecting conductor, the first connecting conductor is connected to the first electrode, and an insulating block is arranged between it and the second electrode. The second part of the first connecting conductor closest to the first side is formed between two adjacent insulating blocks along the first direction.

[0011] In the case of adopting the above-described implementation scheme, based on the arrangement of the first electrode on the battery body, the first connecting conductor is correspondingly configured to collect the current collected by the first electrode. The second part between the insulating blocks is wider than the first part, which is beneficial to dispersing the stress between the second part and the first surface. In this way, not only the connection between the connecting conductor and the electrode is more firm, but also it is beneficial to prevent the connecting conductor from warping.

[0012] In some exemplary embodiments, the connecting conductor includes a second connecting conductor, the second connecting conductor is connected to the second electrode, and an insulating block is arranged between it and the first electrode; the second part of the second connecting conductor closest to the first side is formed between the first side and the insulating block adjacent to the first side.

[0013] In the case of adopting the above-mentioned implementation scheme, based on the arrangement of the second electrode on the battery body, the corresponding second connection conductor is configured to collect the current collected by the second electrode. The second part located between the insulating blocks is wider than the first part, which is beneficial to dispersing the stress between the second part and the second surface. In this way, not only the connection between the connection conductor and the electrode is made more firm, but also it is beneficial to prevent the connection conductor from warping. Moreover, the second part of the second connection conductor located between the first side and the insulating block is also beneficial to shortening the transmission path of the carriers along the second direction, so as to collect the edge current of the battery body more fully.

[0014] In some exemplary embodiments, the first distance between the end of the first connection conductor adjacent to the first side and the first side is greater than the second distance between the end of the second connection conductor adjacent to the first side and the first side.

[0015] In some exemplary embodiments, the first distance is between 1 and 3 millimeters.

[0016] In some exemplary embodiments, the second distance is between 0.5 and 1.5 millimeters.

[0017] In the case of adopting the above-mentioned implementation scheme, for the first connection conductor configured with the first distance, both ends of the first connection conductor along the first direction can be located between the second electrode closest to the first side and the first electrode second closest to the first side. In this way, not only the first connection conductor extends to the insulating block at the outermost edge of the battery body, thus maintaining the connection reliability between the first connection conductor and the first electrode at the edge of the battery body, but also the material used for printing the first connection conductor is saved. The second connection conductor configured with the second distance can effectively collect the edge current of the battery body.

[0018] In some exemplary embodiments, the ratio of the thickness of the second part to the thickness of the first part is between 4 and 10.

[0019] In the case of adopting the above-mentioned implementation manner, the thickness of the first part and the thickness of the second part are related. If it is too thin, it is not conducive to the transmission of current. If it is too thick, it will lead to waste of materials.

[0020] In some exemplary embodiments, the thickness of the second part is greater than or equal to 25 micrometers.

[0021] In the case of adopting the above-mentioned implementation manner, setting the second part thicker is beneficial to maintaining the reliability in the welding state with the external electrical connector, reducing the risk of poor welding, and under the condition of unchanged width, it can also increase the cross-sectional area of the connection conductor to reduce the resistance of the connection conductor.

[0022] In some illustrative embodiments, the thickness of the first part is between 5 micrometers and 15 micrometers.

[0023] In the case of adopting the above implementation, when the thickness of the second part is greater than or equal to 25 micrometers, the first part should be set to an appropriate thickness. If it is set too thin, such as corresponding to the upper limit value of the thickness ratio of 10, it is not conducive to the current transmission between two adjacent fine grids; while if it is set too thick, such as corresponding to the lower limit value of the thickness ratio of 4, it not only wastes the material of the connecting conductor, but also has a small improvement in electrical conduction, and may cause the connecting conductor to extend in the width direction during printing, and then cause short circuit due to overlapping with the opposite fine grid.

[0024] In some illustrative embodiments, along a third direction that is orthogonal to both the first direction and the second direction, the top surface of the first part protrudes from the top surface of the second part.

[0025] In the case of adopting the above implementation, due to the smooth surface of the insulating block, the first part formed on the insulating block is not only thinner than the second part, but also not easy to form an effective connection with the insulating block. For this reason, the second part is the main connection point for effectively connecting the connecting conductor and the electrical connector. On this basis, setting the first part higher than the second part in the third direction can, on the basis of saving materials, ensure that the second part can form a good electrical connection, and at the same time ensure that the first part can form a connecting part connecting two adjacent second parts to prevent broken grids.

[0026] In some illustrative embodiments, the material of the connecting conductor includes silver and copper.

[0027] In the case of adopting the above implementation, the connecting conductor prepared with silver and copper reduces the usage amount of silver paste, which not only reduces the corresponding process cost, but also takes into account the high electrical conductivity and corrosion resistance of the connecting conductor.

[0028] In some illustrative embodiments, the connecting conductor is arranged at the edge of at least one of the two opposite first sides close to the battery body.

[0029] That is, only the connecting conductor at the end is retained, and the connecting conductor is not arranged at the main gridless structure in the middle, so as to achieve the reliability of the end solder strip connection and reduce the material usage amount of the connecting conductor at the same time.

[0030] An embodiment of the present invention further provides a photovoltaic module, including a back contact battery; and an electrical connector electrically connecting the connecting conductors of at least two of the above back contact batteries.

[0031] In the case of adopting the above-mentioned embodiment, a single electrical connector connects the connection conductor of one polarity of one back-contact battery, and at the same time connects the connection conductor of the other polarity of an adjacent back-contact battery, so that multiple back-contact batteries can be connected in series to form a battery string.

[0032] In some schematic embodiments, a plurality of bonding portions are arranged at intervals in a first direction between the above-mentioned electrical connector and the above-mentioned connection conductor, and at least a part of the plurality of bonding portions is arranged on the second portion of the above-mentioned connection conductor.

[0033] In the case of adopting the above-mentioned embodiment, the second portion of the connection conductor serves as the main bonding point for connecting with the first electrode or the second electrode and the electrical connector. By arranging the bonding portion on this second portion, it can have a larger bonding area to effectively and firmly connect the connection conductor and the electrical connector together.

[0034] In some schematic embodiments, the number of the above-mentioned bonding portions arranged on the same connection conductor is between 15 and 24.

[0035] In the case of adopting the above-mentioned embodiment, configuring the bonding portions in this number can provide appropriate tensile force to reliably connect the connection conductor and the electrical connector, and can also prevent waste of the material for preparing the bonding portions.

[0036] In some schematic embodiments, the third distance between the end of the above-mentioned electrical connector located inside the battery body of the back-contact battery and the first side of the adjacent battery body is between 5 and 7 millimeters.

[0037] In the case of adopting the above-mentioned embodiment, keeping a preset third distance between the electrical connector and the edge of the battery body can prevent the hidden crack of the battery body caused by the end of the electrical connector being too close to the edge of the battery body. Description of the Drawings

[0038] Figure 1 is a schematic diagram of a back-contact battery from a top view perspective according to a schematic embodiment of the present invention;

[0039] Figure 2 is Figure 1 a partial enlarged view of part A of the shown schematic embodiment;

[0040] Figure 3 is a schematic diagram of a connection conductor of another schematic embodiment;

[0041] Figure 4 is Figure 1 a partial cross-sectional view of the B1-B2 section of the shown schematic embodiment;

[0042] Figure 5It is a schematic diagram of a photovoltaic module from a top-down perspective according to an exemplary embodiment of the present invention;

[0043] Figure 6 is Figure 5 A partial cross-sectional view of the photovoltaic module of the illustrated exemplary embodiment along a first direction;

[0044] Figure 7 It is a schematic diagram of a back-contact battery from a top-down perspective according to an exemplary embodiment of the present invention.

[0045] In the said drawings, the meanings of the reference numerals are specifically as follows:

[0046] 1. Battery body;

[0047] 2. First electrode;

[0048] 3. Second electrode;

[0049] 4. Connecting conductor;

[0050] 41. First connecting conductor;

[0051] 42. Second connecting conductor;

[0052] 43. Second part;

[0053] 44. First part;

[0054] 45. Protrusion;

[0055] 5. Insulating block;

[0056] 6. Joint part;

[0057] 7. Electrical connector. Detailed implementation manners

[0058] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0059] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0060] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0061] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc. In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.

[0062] The different doping regions on the backlight side of a back contact cell (i.e., BC cell) are alternately distributed in sequence. Correspondingly, the sub-gates arranged on different doping regions are also alternately distributed and have different conduction types. To collect the current collected by the sub-gates, some back contact cells are also provided with a main gate (i.e., Busbar) that intersects with the sub-gates. In addition to connecting to the sub-gates of the same polarity, the arranged main gate also needs to cross the sub-gates of different polarities. Therefore, it is necessary to electrically isolate the main gate from the sub-gates of different polarities.

[0063] Currently, there are mainly two ways to electrically isolate the main gate from the sub-gates of different polarities. One is to set the sub-gate into a discontinuous structure so that the main gate passes through the disconnection part formed by the sub-gates of different polarities. In this way, the main gate is connected to the surfaces of the sub-gate and the battery body. The other is to use a sub-gate with a continuous structure and an insulating block is provided between the overlapping parts of the main gate and the sub-gates of different polarities. In this way, the main gate is connected to the sub-gate and the insulating block.

[0064] The latter method mentioned above can more effectively avoid the electrical contact between the sub-gates of different polarities than the former method, which is beneficial to reducing the short-circuit current and leakage current. However, based on the material characteristics of the insulating block (such as insulating glue, silicon oxide, silicon nitride, or other materials), the surface of the insulating block is smooth and the middle part is more convex than the two sides. In this way, it is not conducive to forming an effective connection with the part of the main gate located on the insulating block. Compared with the former method, the reliability of the connection between the main gate and the sub-gate is lower. And the part of the main gate located on the insulating block often also forms a roughly arched structure following the shape of the insulating block, which is also not conducive to forming an effective connection with the external interconnection bar.

[0065] In view of this, how to provide a back contact cell and a photovoltaic module that are conducive to effectively connecting the main gate and the sub-gate, as well as the external interconnection bar, has become an urgent technical problem to be solved.

[0066] Figure 1It is a schematic diagram of a back-contact battery from a top-down perspective according to an exemplary embodiment of the present invention. Figure 2 is Figure 1 a partial enlarged view of part A of the illustrated exemplary embodiment.

[0067] The back-contact battery provided according to the present invention, as Figure 1 and Figure 2 shown, the back-contact battery of the present invention can be a traditional IBC battery (interdigitated back-contact battery), or a TBC battery (TOPCon back-contact battery), an HBC battery (heterojunction back-contact battery), or a hybrid back-contact battery (i.e., the PN passivation therein is different passivation materials, for example, it can be a combination of polysilicon passivation and amorphous / microcrystalline passivation).

[0068] The above-mentioned back-contact battery includes a battery body 1, and the battery body 1 at least includes a substrate and a doped layer on the substrate. The substrate has a rectangular or square structure, and the length of its first side (such as Figure 1 the long side shown) or the second side (such as Figure 1 the short side shown) is between 182 and 240 mm. Preferably, it can be (182±2)*(191±2) mm, (182±2)*(210±2) mm, (210±2)*(210±2) mm.

[0069] The battery body 1 of the above-mentioned IBC battery (interdigitated back-contact battery) includes a first doped semiconductor part and a second doped semiconductor part that are alternately arranged at intervals along a first direction on the substrate to form an interdigitated doped part structure. One of the first doped semiconductor part and the second doped semiconductor part is n-type doped, and the other is p-type doped. Electrode structures are respectively arranged at intervals in the first doped semiconductor part and the second doped semiconductor part.

[0070] The battery body 1 of the above-mentioned TBC battery (TOPCon back-contact battery) includes a tunneling oxide layer provided on the substrate, and a first doped semiconductor part and a second doped semiconductor part formed by a doped polysilicon layer. Among them, the TOPCon structure formed by the stacked tunneling oxide layer and the doped polysilicon layer can provide higher carrier lifetime and lower surface recombination compared with the IBC battery, which is beneficial to improving the photoelectric conversion efficiency of the TBC battery.

[0071] The cell body 1 of the above-mentioned HBC cell (heterojunction back contact cell) includes an n-type doped layer and a p-type doped layer stacked on a substrate to form a heterojunction structure. Among them, the n-type doped layer includes, but is not limited to, microcrystalline silicon or amorphous silicon (to provide electrons), and the p-type doped layer can also use microcrystalline silicon or amorphous silicon (such as using boron as a dopant to provide holes). The HBC cell helps to improve the carrier lifetime and reduce surface recombination. Further, a transparent conductive oxide layer (i.e., TCO) can also be provided between the surfaces of the n-type doped layer and the p-type doped layer and the electrodes, which is beneficial to collecting carriers in the doped region and can also play a certain antireflection role.

[0072] The cell body 1 of the above-mentioned hybrid back contact cell can adopt a layer structure similar to that of an IBC cell or a TBC cell, and a corresponding passivation layer structure is configured on this basis, such as a combination of at least two of polysilicon passivation, amorphous silicon passivation, and microcrystalline silicon passivation.

[0073] Based on the back contact cell of any of the above embodiments, such as Figure 1 and Figure 2 As shown, the above-mentioned back contact cell further includes a first electrode 2 and a second electrode 3 provided on the first surface of the cell body 1 (such as the backlight surface of the cell body 1, that is, Figure 1 the surface facing the viewing angle shown, and the corresponding second surface is the light-receiving surface). The first electrode 2 and the second electrode 3 (which can also be called fine grids, collector grid lines, sub-grids, etc., and the first electrode 2 and the second electrode 3 have different polarities and are respectively used to extract the majority carriers or minority carriers of different doped regions) are alternately arranged at intervals along the first direction (such as Figure 1 the up-down direction shown) and extend along the second direction (such as Figure 1 the left-right direction shown). A connecting conductor 4 is provided on the first surface and extends along the first direction (such as Figure 1 the up-down direction shown). The connecting conductor 4 is connected to one of the first electrode 2 and the second electrode 3, and an insulating block 5 is provided between it and the other.

[0074] Among them, the connecting conductor 4 (which can be called the main grid in some cases and is used to aggregate the current collected by the first electrode 2 or the second electrode 3) includes a first part 44 provided on the insulating block 5 and a second part 43 provided outside the insulating block 5. The first width of the first part 44 along the second direction is smaller than the second width of the second part 43 along the second direction.

[0075] Among them, a plurality of insulating blocks 5 are discretely distributed on the first electrode 2 or the third electrode 3.

[0076] In such an embodiment, the second part 43, which is wider than the first part 44, is used to connect to the first electrode 2 or the second electrode 3. In this way, the part of the connecting conductor 4 that connects the electrodes (i.e., the first electrode 2 or the second electrode 3) in the second direction is wider, and has a larger bonding area with the battery body 1, which can effectively improve the connection reliability between the connecting conductor 4 and the electrodes; and when the second part 43 is connected to the external electrical connector 7, since the width of the second part 43 is larger, it also has a larger area than the first part 44. Therefore, a joint part 6 with a larger area can be formed between it and the electrical connector 7, which is beneficial to improving the tensile force between the connecting conductor 4 and the electrical connector 7.

[0077] The back-contact battery schematically shown in the present invention can also be a battery structure without a main grid (i.e., 0BB). Specifically, the first electrode 2 and the second electrode 3 (which can also be called fine grids, collector grid lines, sub-grids, etc. on the first surface of the battery body 1, and the first electrode 2 and the second electrode 3 have different polarities and are respectively used to extract the majority carriers or minority carriers of different doped regions) are directly connected to the external electrical connector 7 (which can also be called a solder strip or an interconnection bar and is used to connect at least two back-contact batteries in series) without passing through the main grid. At this time, the connecting conductor 4 can be regarded as the joint part 6 connecting the solder strip or can also be regarded as the main grid structure connecting the first electrode 2 or the second electrode 3.

[0078] On this basis, the connecting conductor 4 is arranged between the first electrode 2 or the second electrode 3 and the electrical connector 7, and it can be used as a joint part (which can be solder, solder paste, such as solder, for welding the sub-grid and the solder strip; or it can be a conductive adhesive layer, such as conductive silver paste, conductive glue, etc., for conducting bonding between the sub-grid and the solder strip), so as to form a good welding relationship between the electrode (i.e., the first electrode 2 or the second electrode 3) and the electrical connector 7.

[0079] Furthermore, in this embodiment, the connecting conductor 4 is prefabricated at a specific position on the battery body 1. Furthermore, during the process of welding the electrode to the electrical connector, the electrical connector has a joint part, and this joint part melts and is joined and mutually dissolved with the connecting conductor 4 to form an intermetallic compound (i.e., IMC).

[0080] In a schematic embodiment, as Figure 1 shown, the insulating block 5 includes but is not limited to insulating small blocks configured to be generally rectangular. Specifically, the width of the insulating small block should be configured to be greater than the width of the connecting conductor 4 (should be greater than the second width), so that the part of the connecting conductor 4 that coincides with the first electrode 2 in the orthographic projection direction of the battery body 1 is completely covered to electrically isolate the connecting conductor 4 and the first electrode 2. The insulating block 5 can be made of inorganic materials, such as silicon oxide, silicon nitride, etc., or can also be made of organic materials, such as insulating glue, etc.

[0081] In a schematic embodiment, as Figure 1 shown, a plurality of insulating blocks (i.e., insulating block 5) are provided on the first electrode 2. Specifically, the plurality of insulating blocks on each first electrode 2 are arranged at intervals along the first direction (such as Figure 1 the up-down direction shown).

[0082] In a schematic embodiment, taking the battery body 1 with an n-type silicon substrate as an example, the first electrode 2 is disposed on the n-type doped region, and the corresponding second electrode 3 is disposed on the p-type doped region. Corresponding to the respective doped regions, the first electrode 2 serves as the positive electrode of the back contact battery, and the second electrode 3 serves as the negative electrode of the back contact battery. Similarly, the first electrode 2 can also be disposed on the p-type doped region to serve as the negative electrode, and the second electrode 3 can also be disposed on the n-type doped region to serve as the positive electrode.

[0083] According to an embodiment of the present invention, as Figure 1 shown, the battery body 1 includes two opposite first sides (such as Figure 1 the long sides shown, i.e., the upper side and the lower side) and two opposite second sides (such as Figure 1 the short sides shown, i.e., the left side and the right side). Among them, the connecting conductor 4 includes a first connecting conductor 41. The first connecting conductor 41 is connected to the first electrode 2, and an insulating block 5 is provided between the first connecting conductor 41 and the second electrode 3. The second part 43 of the first connecting conductor 41 closest to the first side is formed between two adjacent insulating blocks 5 along the first direction.

[0084] According to an embodiment of the present invention, as Figure 1 shown, the connecting conductor 4 includes a second connecting conductor 42. The second connecting conductor 42 is connected to the second electrode 3, and an insulating block 5 is provided between the second connecting conductor 42 and the first electrode 2. The battery body 1 has a first side extending in the second direction, and the second part 43 of the second connecting conductor 42 closest to the first side is formed between the first side and the insulating block 5 adjacent to the first side.

[0085] In a schematic embodiment, as Figure 1 shown, the electrodes closest to the two first sides are both the second electrodes 3. Further, the second part 43 of the second connecting conductor 42 closest to the first side is located between the first side and the insulating block 5 adjacent thereto, while the second part 43 of the second connecting conductor 42 located in the middle is located between two adjacent insulating blocks along the first direction (such as Figure 1 the up-down direction shown). Correspondingly, the second parts 43 of the first connecting conductor 41 are all located between adjacent insulating blocks along the first direction.

[0086] In such an embodiment, based on the arrangement of the first electrode 2 and the second electrode 3 on the battery body 1, the corresponding connecting conductors 4 (i.e., the first connecting conductor 41 and the second connecting conductor 42) are configured to collect the current collected by the first electrode 2 or the second electrode 3 respectively. The second part 43 of the connecting conductor 4 is wider than the first part 44, which can form a larger cross-sectional area, is beneficial to reducing the series resistance between the electrodes, and correspondingly improving the fill factor and output power of the back contact battery. Moreover, since the second part 43 of the connecting conductor 4 connected to the electrode occupies a larger area in the first surface than the first part 44, it is also beneficial to disperse the stress between the second part 43 and the first surface. In this way, not only the connection between the connecting conductor and the electrode is more firm, but also it is beneficial to prevent the connecting conductor from warping. In addition, the second part 43 of the second connecting conductor 42 located between the first side and the insulating block 5 is also beneficial to shortening the transmission path of the carriers along the second direction, and can collect the edge current of the battery body more fully.

[0087] According to an embodiment of the present invention, as Figure 1 shown, the first distance between the end of the first connecting conductor 41 adjacent to the first side and the first side is greater than the second distance between the end of the second connecting conductor 42 adjacent to the first side and the first side.

[0088] According to an embodiment of the present invention, as Figure 1 shown, the first distance is between 1 and 3 millimeters.

[0089] According to an embodiment of the present invention, as Figure 1 shown, the second distance is between 0.5 and 1.5 millimeters.

[0090] In such an embodiment, in the orthographic projection along the thickness direction (i.e., the following third direction) of the battery body 1, both ends of the first connecting conductor 41 along the first direction (such as Figure 1 the upper end and the lower end shown) are located between the second electrode 3 closest to the first side and the first electrode 2 next closest to the first side, that is, the end of the first connecting conductor 41 extends to the insulating block 5 and does not exceed the second electrode 3 covered by the insulating block 5. In this way, not only the first connecting conductor 41 extends to the insulating block 5 at the outermost edge of the battery body 1 to maintain the connection reliability between the first connecting conductor 41 and the first electrode at the edge of the battery body 1, but also the material used for printing the first connecting conductor 41 is saved. And the second connecting conductor 42 configured with the above second distance adaptively shortens the transmission distance of the carriers in the first direction and the second direction, and can effectively collect the edge current of the battery body. Especially when the second electrode 3 is a negative electrode, the second connecting conductor 42 can reduce the surface recombination of minority carriers, thereby effectively collecting the minority carriers.

[0091] According to an embodiment of the present invention, asFigure 2 As shown, both ends of the second part 43 protrude from the first part 44 along the second direction. The portions of each end of the second part 43 that protrude from the first part 44 have a width along the second direction that is between 80 and 250 micrometers.

[0092] According to an embodiment of the present invention, as Figure 2 shown, the first width is between 0.5 and 1.5 millimeters.

[0093] In a schematic embodiment, as Figure 1 and Figure 2 shown, the connecting conductor 4 can be regarded as having a main body portion extending along the first direction (forming a substantially rectangular structure), and a plurality of protruding portions protruding to both sides along the second direction (such as the up and down direction shown in Figure 1 shown) are uniformly arranged on the main body portion along the first direction (such as the left and right direction shown in Figure 1 shown). That is, the semi-circular or semi-elliptical portions shown in Figure 2 shown. Among them, the first width of the first part 44 (that is, W1 shown in Figure 2 shown) can be regarded as the width of the main body portion; while the second width of the second part 43 (that is, W2 shown in Figure 2 shown) can be regarded as the sum of the widths of the two protruding portions (that is, W3 shown in Figure 2 shown) and the width of the main body portion (that is, W2 = W1 + 2×W3). In addition, in other embodiments, along the second direction, the widths of the left and right protruding portions can be different.

[0094] In a schematic embodiment, as Figure 2 shown, the first width of the first part 44 includes but is not limited to being configured to be 0.5 to 1.5 millimeters (that is, W1 = 0.5 mm to 1.5 mm). Correspondingly, the width of the protruding portion includes but is not limited to being configured to be 80 to 250 micrometers (that is, W3 = 80 μm to 250 μm), that is, the second width of the second part 43 includes but is not limited to being configured to be 0.66 to 2.0 millimeters (that is, W2 = 0.66 mm to 2.0 mm). In a preferred embodiment, the first width of the first part 44 includes but is not limited to being configured to be 1 millimeter, the width of the protruding portion includes but is not limited to being configured to be 100 micrometers, and the second width of the second part 43 is correspondingly configured to be 1.2 millimeters.

[0095] In such an embodiment, when the connecting conductor 4 with the above-mentioned size design is engaged with the electrical connector 7, it is beneficial to increase the specific surface area of the engaging portion 6, thereby improving the tensile force between the connecting conductor and the electrical connector.

[0096] In a schematic embodiment, as Figure 2As shown, the protruding portions are arranged at intervals along the first direction on the main body portion to form a second portion 43 similar to a runway shape; correspondingly, the first portion 44 located between two adjacent second portions 43 forms a substantially rectangular structure.

[0097] Figure 3 It is a schematic diagram of a connecting conductor of another exemplary embodiment.

[0098] In another exemplary embodiment, as Figure 3 shown, the protruding portions are arranged continuously along the first direction on the main body portion, so that the edge of the connecting conductor 4 forms a continuous wavy structure. Wherein, the first width is the maximum width of the overlapping portion of the connecting conductor 4 and the insulating block 5. It should be understood that the embodiments of the present invention are not limited thereto.

[0099] For example, the second portion can also be configured as an ellipse, a rectangle, a polygon or other shapes suitable for connecting the electrode and the electrical connector 7 and forming a reliable connection.

[0100] Figure 4 is Figure 1 a partial cross-sectional view of the B1-B2 cross-section of the exemplary embodiment shown.

[0101] In an exemplary embodiment, as Figure 4 shown, the small insulating block (i.e., the insulating block) located above the first electrode 2 often forms a substantially arched cross-sectional shape (i.e., the middle part on the first electrode 2 as shown in Figure 4 protrudes upward, and the edge portions on both sides of the middle part are thinner). Further, the connecting conductor 4 extends along the first direction (such as the left-right direction as shown in Figure 4 ), that is, the first portion 44 located on the insulating block 5 and the second portion 43 formed between adjacent insulating blocks 5 are formed. Among them, Figure 4 only shows schematically that the connecting conductor 4 straddles two insulating blocks 5. It should be understood that the connecting conductor 4 can straddle each insulating block 5 arranged along the first direction.

[0102] According to the embodiment of the present invention, as Figure 4 shown, the ratio of the thickness of the second portion 43 to the thickness of the first portion 44 is between 4 and 10.

[0103] In such an embodiment, the thickness of the second portion 43 and the thickness of the first portion 44 are related. If it is too thin, it is not conducive to current transmission. If it is too thick, it will cause waste of materials.

[0104] According to the embodiment of the present invention, as Figure 4 shown, the thickness of the second portion 43 is greater than or equal to 25 microns.

[0105] In such an embodiment, setting the second portion 43 thicker is beneficial to maintaining the reliability of the second portion 43 with the external electrical connector in the welding state, reducing the risk of poor welding, and under the condition that the width remains unchanged, the cross-sectional area of the connecting conductor can be increased to reduce the resistance of the connecting conductor.

[0106] According to an embodiment of the present invention, Figure 2 As shown, the thickness of the first portion 44 is 5 micrometers to 15 micrometers.

[0107] In such an embodiment, for the thickness of the second portion 43 being greater than or equal to 25 microns, the first portion 44 should be set to a suitable thickness. If it is set too thin, such as the upper limit value corresponding to the thickness ratio of 10, it is not conducive to the current transmission of two adjacent fine grids; and if it is set too thick, such as the lower limit value corresponding to the thickness ratio of 4, it not only wastes the material of the connecting conductor, but also has little improvement on the electrical conduction, and may cause the connecting conductor to extend in the width direction during printing, and then cause overlap with another opposite fine grid to cause a short circuit.

[0108] According to an embodiment of the present invention, Figure 4 As shown, along the first direction (such as Figure 4 left and right directions as shown) and a second direction (as shown Figure 1 The third direction (such as Figure 4 In the up-down direction shown in FIG. 4 , the top surface of the first portion 44 protrudes from the top surface of the second portion 43.

[0109] In an exemplary embodiment, the surface of the first portion 44 facing away from the battery body 1 (eg Figure 4 The upper surface shown in FIG. 4 is more protruding than the second portion 43. In this way, on the basis of saving the amount of slurry used for the connecting conductor, it is helpful to improve the bonding force between the electrical connector 7 and the connecting conductor 4, and increase the contact area to increase the pulling force between the electrical connector 7 and the connecting conductor 4, while reducing the contact resistance.

[0110] In an illustrative embodiment, Figure 4 As shown, the surfaces of the first portion 44 and the second portion 43 facing away from the battery body 1 (such as Figure 4 The upper surface of the second portion 43 is formed with non-uniform protrusions 45. The protrusions on the second portion 43 may be more protruding than the protrusions on the first portion 44, so that the roughness of the surface of the second portion 43 is greater than the roughness of the surface of the first portion 44 (the roughness may be considered as the average roughness of the curved surface).

[0111] In such an embodiment, the protrusion 45 provided on the second part 43 protrudes more than the first part 44, which can make the surface of the second part 43 rougher. In this way, when the connecting conductor 4 is connected to the external electrical connector 7 and the joint 6, a larger contact area can be formed, so as to increase the tensile force between the electrical connector 7 and the connecting conductor 4 and effectively reduce the contact resistance. The relatively smooth first part 44 can avoid the situation that the protrusion of the protrusion 45 is too large and pierces the insulating block.

[0112] According to an embodiment of the present invention, the material of the connecting conductor 4 includes but is not limited to silver and copper.

[0113] In a schematic embodiment, as Figure 4 shown, the width of the first electrode 2 (i.e., W4 as shown in Figure 4 the figure) includes but is not limited to being configured to be between 30 micrometers and 100 micrometers. And / or, the width of the second electrode 3 (i.e., W5 as shown in Figure 4 the figure) includes but is not limited to being configured to be between 30 micrometers and 100 micrometers.

[0114] In such an embodiment, setting the widths of the first electrode 2 and the second electrode 3 to be relatively narrow helps to improve the fill factor and output power of the back-contact battery, and helps to optimize the current flow path to reduce current congestion and potential loss points.

[0115] In a schematic embodiment, the first electrode 2 and the second electrode 3 can be formed by printing methods such as screen printing, as Figure 4 shown. At this time, the widths of both the first electrode 2 and the second electrode 3 can be between 30 micrometers and 100 micrometers. Specifically, the first electrode 2 is disposed on the majority-carrier doped region, and the second electrode 3 is disposed on the minority-carrier doped layer. Further, the width of the first electrode 2 (i.e., W4) is configured to be less than the width of the second electrode 3 (i.e., W5), that is, 30μm ≤ W4 ≤ 100μm, 30μm ≤ W5 ≤ 100μm, and W4 < W5. Further, the thickness (i.e., height) of the first electrode 2 and the second electrode 3 includes but is not limited to being configured to be between 8 and 15 micrometers, and preferably can be configured to be about 10 micrometers.

[0116] In such an embodiment, taking a battery body with an n-type silicon wafer as a substrate as an example, electrons are the majority carriers and holes are the minority carriers. Correspondingly, the p-type doped region serves as the minority carrier region for collecting minority carriers, that is, holes; correspondingly, the n-type doped region serves as the majority carrier region for collecting majority carriers, that is, electrons. Based on the characteristics of the back-contact battery, when collecting minority carriers through the second electrode 3, holes will also laterally transport in the substrate. During this process, holes are prone to carrier recombination with the majority carriers in the majority carrier region. Therefore, setting the second electrode 3 located in the minority carrier doped region wider can more effectively improve the collection efficiency of the second electrode 3 for minority carriers.

[0117] In a schematic embodiment, the first electrode 2 and the second electrode 3 can be directly electrically connected to the corresponding doped regions, or a transparent conductive oxide (such as TCO) layer can be provided between the electrodes (i.e., the first electrode 2 and the second electrode 3) and the corresponding doped regions. Based on the above-mentioned collection efficiency for minority carriers, the minority carrier doped region and / or the transparent conductive oxide layer located on the minority carrier doped region can also be designed wider to further improve the collection efficiency of minority carriers. Among them, the first electrode 2 and / or the second electrode 3 are formed on the battery body 1 by, but not limited to, electroplating, evaporation, chemical vapor deposition, etc.

[0118] Similarly, taking a battery body with a p-type silicon wafer as a substrate as an example, electrons are the minority carriers and holes are the majority carriers. Therefore, the electrode located on the minority carrier doped region should also be set wider, and the specific effects will not be elaborated here. It should be understood that the embodiments of the present invention are not limited thereto.

[0119] For example, the widths of the first electrode 2 and the second electrode 3 can be set to be approximately equal.

[0120] Again, the width of the first electrode 2 can be set to be greater than the width of the second electrode 3. Specifically, it should be appropriate to meet the collection requirements of the corresponding photo-generated carriers, which will not be elaborated here.

[0121] In a schematic embodiment, as Figure 4 shown, a separation region is formed between the first electrode 2 and the second electrode 3 along the first direction. Specifically, the insulating block 5 extends from the upper part of the first electrode 2 to this separation region and is spaced from the second electrode 3. The part between the insulating block 5 and the second electrode is covered by the connecting conductor 4 (the covered part is only the region within the width range of the connecting conductor 4) to maintain the insulation effect between the first electrode 2 and the second electrode 3 (and the connecting conductor 4), and at the same time reserve enough width to ensure that the connecting conductor can be in full contact with the second electrode.

[0122] In another exemplary embodiment, not shown in the figures, the first electrode 2 and the second electrode 3 may be formed by a deposition process such as electroplating. In this case, the width of the first electrode 2 is 300 micrometers to 600 micrometers. And / or, the width of the second electrode 3 is 300 micrometers to 600 micrometers.

[0123] In an exemplary embodiment, the widths of both the first electrode 2 and the second electrode 3 can be 300 micrometers to 600 micrometers. Specifically, the first electrode 2 is disposed on a majority-carrier doped region, and the second electrode 3 is disposed on a minority-carrier doped layer. Further, the width of the first electrode 2 (i.e., W4) is configured to be less than the width of the second electrode 3 (i.e., W5), that is, 300μm ≤ W4 ≤ 600μm, 300μm ≤ W5 ≤ 600μm, and W4 < W5. Further, the sum of the areas of the first electrode 2 and the second electrode 3 on the first surface includes but is not limited to 50% or more of the total area of the first surface.

[0124] In this embodiment, by setting the width of the second electrode 3 wider, the technical effects generated are similar to those of the Figure 4 embodiment shown above. That is, the electrode (i.e., the second electrode 3) located on the minority-carrier doped region is set wider, so as to improve the collection effect of minority carriers. Therefore, it will not be elaborated here.

[0125] In such an embodiment, the first surface is the backlight surface of the back-contact battery. Therefore, there is no need to consider its light-shielding loss. On this basis, by increasing the widths of the first electrode 2 and the second electrode 3 and the area ratio they occupy on the first surface, the current collection efficiency can be effectively improved, especially the collection efficiency of minority carriers on the minority-carrier doped region. And setting electrodes with a larger width can also increase their cross-sectional areas, which can effectively reduce the series resistance. In addition, the wider first electrode 2 and second electrode 3 can also distribute the electric field more evenly and provide support for the battery body 1, which is still beneficial to improving the structural strength of the battery body.

[0126] Based on the above embodiments, a portion of the battery body 1 located between adjacent first electrodes 2 and second electrodes 3 forms an isolation region. The insulating block 5 covers the isolation region and extends onto the second electrode 3.

[0127] On the premise that the width of the battery body 1 is limited, if the widths of the first electrode 2 and the second electrode 3 are set wider, the distance between the first electrode 2 and the second electrode 3 in the first direction will be smaller. Therefore, the insulating block 5 is used to cover the entire isolation region and extend onto the second electrode 3, which can not only maintain the insulation between the first electrode 2 and the second electrode 3 in the first direction, but also prevent the connecting conductor 4 from entering the isolation region to avoid leakage caused by excessive electric field strength in the isolation region.

[0128] In a schematic embodiment, the connecting conductor 4 is made by, but not limited to, the silver-coated copper method. Specifically, the connecting conductor 4 is printed with a copper-based paste for the inner layer; after sintering it, a silver-based paste is then used to print the outer layer, and sintering is carried out again to melt the silver particles and combine them with the copper main grid, forming a main grid with a silver-coated copper structure.

[0129] In such an embodiment, the connecting conductor 4 made of silver and copper reduces the amount of silver-based paste used, thereby reducing the corresponding process cost. Moreover, it also takes into account the high conductivity and corrosion resistance of the connecting conductor. It should be understood that the embodiments of the present disclosure are not limited to this.

[0130] For example, the connecting conductor 4 can also be made only of silver; for example, the connecting conductor 4 can also be made of other base metals, such as pure copper, pure aluminum, etc.; or the connecting conductor 4 can also be made of other alloy materials.

[0131] Figure 5 It is a schematic diagram of a top view of a photovoltaic module according to a schematic embodiment of the present invention.

[0132] Based on the same inventive concept, the present invention also provides a photovoltaic module, as Figure 5 shown, including a back contact cell and an electrical connector 7 (which can also be called a solder ribbon or an interconnection bar for connecting at least two back contact cells in series). The electrical connector 7 electrically connects the connecting conductors 4 of at least two back contact cells. A joint portion 6 is provided between the electrical connector 7 and the connecting conductor 4.

[0133] In a schematic embodiment, the joint portion 6 can use solder, which can also be called solder paste, such as solder. Further, before welding the connecting conductor 4 to the electrical connector 7, the solder should be preset on the second part 43 of the connecting conductor 4. Since the second part 43 has a larger area, when welding the connecting conductor 4 to the electrical connector 7, the solder can form a larger specific surface area when melting, so as to improve the welding tensile force.

[0134] In another schematic embodiment, the joint portion 6 can use a conductive adhesive, such as conductive glue, solder paste, etc. Further, in the embodiment of connecting the connecting conductor 4 to the electrical connector 7 using gray glue, the electrical connector 7, the gray glue, and the connecting conductor are stacked. In a preferred embodiment, the thickness (i.e., height) of the electrical connector 7 is configured to be, but not limited to, between 100 and 250 microns (such as 200 microns), the thickness (i.e., height) of the gray glue is configured to be, but not limited to, between 10 and 50 microns (such as 25 microns), and the thickness (i.e., height) of the connecting conductor 4 is configured to be, but not limited to, between 20 and 60 microns (such as 40 microns).

[0135] In such an embodiment, the electrical connector 7 is used to connect the connection conductors 4 of different back-contact batteries, and the connection conductors 4 of adjacent back-contact batteries have opposite polarities, so that multiple back-contact batteries can be connected in series to form a battery string. Figure 6 is Figure 5 A partial cross-sectional view of a photovoltaic module along a first direction of the schematic embodiment shown.

[0136] In an embodiment according to the present invention, as Figure 5 and Figure 6 shown, a plurality of joint portions 6 are arranged at intervals in the first direction between the electrical connector 7 and the connection conductor 4, and at least a part of the plurality of joint portions 6 is arranged on the second portion 43 of the connection conductor 4. In a schematic embodiment, as Figure 5 and shown in 6, the joint portion 6 is arranged on a part of the second portion 43 arranged at intervals, that is, the first of two adjacent second portions 43 is provided with the joint portion 6. Specifically, in the positive projection along the third direction (such as Figure 5 the direction of the viewing angle shown), the joint portion 6 can coincide with the projection of the electrode (that is, the first electrode 2 or the second electrode 3), or can be misaligned with the projection of the electrode (that is, the first electrode 2 or the second electrode 3). Such a setting can save the use of joint portion materials, and at the same time can achieve an electrical interconnection effect similar to that of a continuous joint portion. Further, the joint portions 6 are preferably arranged at equal intervals in the first direction (such as Figure 5 the up and down direction shown). It should be understood that the embodiments of the present invention are not limited thereto.

[0137] For example, the joint portion 6 can be arranged on each second portion 43 of the connection conductor 4. In such an embodiment, the second portion 43 of the connection conductor 4 serves as a main joint point for connecting with the first electrode 2 or the second electrode 3 and the electrical connector 7. By arranging the joint portion 6 on the second portion 43, it can have a larger joint area to effectively and firmly connect the connection conductor 4 and the electrical connector 7, and the equally spaced joint portions 6 are beneficial to reducing the risk of crack during series soldering.

[0138] According to an embodiment of the present invention, the joint portion 6 is preferably completely arranged on the second portion 43 with a larger width, which can shorten the current transmission path; and makes the joint portion 6 and the connection conductor 4 have a larger joint area.

[0139] In an embodiment according to the present invention, not shown in the figure, the number of joint portions 6 provided on the same connection conductor 4 is between 15 and 24.

[0140] In a schematic embodiment, the number of engaging portions 6 provided on the connecting conductor 4 is preferably configured to be any number between 18 and 21. Further, the spacing between adjacent engaging portions 6 is preferably configured to be between 3.8 and 4.2 millimeters, such as 3.9 millimeters. It should be understood that the embodiments of the present invention are not limited thereto.

[0141] For example, the number of engaging portions 5 can also be configured to be 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26 or any other number, preferably adapted to the length of the connecting conductor 4 and the spacing requirements between adjacent engaging portions 6. Among them, the length of the connecting conductor 4 includes but is not limited to being configured to be between 90 and 110 millimeters.

[0142] In a schematic embodiment, the length of the connecting conductor 4 (i.e., the spacing between the two ends along the first direction) includes but is not limited to being configured to be between 90 and 110 millimeters. Further, the number of engaging portions 6 provided on the connecting conductor 4 is preferably configured to be any number between 18 and 21.

[0143] In such an embodiment, the engaging portions 6 of the above-mentioned number can provide a tensile force of more than 1 N (i.e., Newton) for the connecting conductor 4 and the electrical connector 7. Correspondingly, as the number of engaging portions 6 increases, the tensile force between the connecting conductor 4 and the electrical connector 7 gradually increases, but the increase in its number and tensile force is non-linear. Therefore, if the number of engaging portions 6 is too large, the tensile force between the connecting conductor 4 and the electrical connector 7 cannot be significantly increased, and it will also cause waste of the material for preparing the engaging portions 6. Therefore, configuring the engaging portions to this number can provide a suitable tensile force to reliably connect the connecting conductor 4 and the electrical connector 7, and prevent waste of the material for preparing the engaging portions 6.

[0144] According to an embodiment of the present invention, as Figure 5 shown, the end portion of the electrical connector 7 located in the battery body 1 of the back-contact battery (such as Figure 5 the upper end of the electrical connector located on the left as shown) and the first side of the adjacent battery body 1 (such as Figure 5 the upper side as shown) the third spacing (i.e., as Figure 5 shown S3) is between 1 and 5 millimeters (i.e., 1mm ≤ S3 ≤ 5mm). In a preferred embodiment, the third spacing can be configured to be about 4.0 millimeters.

[0145] According to an embodiment of the present invention, the third spacing S3 is greater than the second spacing S2, and the third spacing S3 is greater than the first spacing S1. This can prevent the solder tape from protruding from the battery body 1 and causing a short circuit.

[0146] Based on the structural characteristics of the back-contact battery, the part closer to the edge of the battery body is more likely to generate hidden cracks under stress. Therefore, in the above-described embodiment, a preset third spacing is maintained between the electrical connector 7 and the edge of the battery body 1, which can prevent the hidden cracks that occur in the battery body 1 when the electrical connector 7 interconnecting strip is connected to the connecting conductor 4 (such as welding or bonding).

[0147] Figure 7 It is a schematic diagram of a back-contact battery from a top-down perspective according to an exemplary embodiment of the present invention.

[0148] According to an embodiment of the present invention, the connecting conductor 4 is disposed at the edge of at least one of the two opposite first sides of the battery body 1 close to the battery body 1. As Figure 7 shown, a main grid is disposed at the edge of the first side of the battery body 1 close to the battery body 1 (area A), and no main grid is disposed in the area away from the first side of the battery body 1 (area B).

[0149] According to an embodiment of the present invention, due to the limitations of the solder ribbon preparation process and equipment, it is difficult to form the solder ribbon at the edge of the back surface of the back-contact battery (the solder ribbon formed on the back edge is likely to cause a short circuit), so it is difficult to collect the current on the fine grid at the back edge of the back-contact battery. By forming the first connecting conductor 41 and the second connecting conductor 42 at the edge of the back surface of the back-contact solar cell, it is more conducive to collecting the carriers at the back edge and improving the efficiency of the battery.

[0150] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", etc., are only for reference to the drawings and are not used to limit the protection scope of the present invention. Throughout the drawings, the same elements are denoted by the same or similar reference numerals. When it may cause confusion in the understanding of the present invention, the conventional structures or configurations will be omitted.

[0151] The embodiments of the present invention have been described above. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present invention. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present invention.

Claims

1. A back-contact battery, characterized in that, Comprising: A battery body (1) having opposite first and second surfaces; A first electrode (2) and a second electrode (3) disposed on the first surface of the battery body (1), the first electrode (2) and the second electrode (3) being alternately arranged at intervals in a first direction in sequence and extending in a second direction perpendicular to the first direction; A connecting conductor (4) disposed on the first surface and extending in the first direction, the connecting conductor (4) being connected to one of the first electrode (2) and the second electrode (3), and an insulating block (5) being provided between the connecting conductor (4) and the other; Wherein, the connecting conductor (4) includes a first portion (44) disposed on the insulating block (5) and a second portion (43) disposed outside the insulating block (5), a first width of the first portion (44) in the second direction being smaller than a second width of the second portion (43) in the second direction, and the first portion (44) and the second portion (43) being integral.

2. The back-contact battery according to claim 1, wherein Both ends of the second portion (43) in the second direction protrude from the first portion (44), and a width of a portion of each end of the second portion (43) protruding from the first portion (44) in the second direction is between 80 and 250 microns.

3. The back-contact battery according to claim 1, characterized in that, The first width is between 0.5 and 1.5 millimeters.

4. The back-contact battery according to claim 1, characterized in that, The battery body (1) has a first side extending in the second direction; The connecting conductor (4) includes a first connecting conductor (41), the first connecting conductor (41) being connected to the first electrode (2), and the insulating block (5) being provided between the first connecting conductor (41) and the second electrode (3), and the second portion (43) of the first connecting conductor (41) closest to the first side being formed between two adjacent insulating blocks (5) in the first direction.

5. The back contact battery according to claim 4, characterized in that, The connecting conductor (4) includes a second connecting conductor (42), the second connecting conductor (42) being connected to the second electrode (3), and the insulating block (5) being provided between the second connecting conductor (42) and the first electrode (2); The second portion (43) of the second connecting conductor (42) closest to the first side is formed between the first side and the insulating block (5) adjacent to the first side.

6. The back-contact battery according to claim 5, wherein, A first distance between an end of the first connecting conductor (41) adjacent to the first side and the first side is greater than a second distance between an end of the second connecting conductor (42) adjacent to the first side and the first side.

7. The back-contact battery according to claim 6, wherein The first distance is between 1 and 3 millimeters.

8. The back-contact battery according to claim 6, characterized in that, The second distance is between 0.5 and 1.5 millimeters.

9. The back-contact battery according to claim 1, characterized in that, A ratio of a thickness of the second portion (43) to a thickness of the first portion (44) is between 4 and 10.

10. The back-contact battery according to claim 9, wherein, The thickness of the first portion (44) is between 5 microns and 15 microns.

11. The back-contact battery according to claim 9, wherein, The thickness of the second portion (43) is greater than or equal to 25 microns.

12. The back-contact battery according to claim 1, wherein, In a third direction orthogonal to both the first direction and the second direction, a top surface of the first portion (44) is higher than a top surface of the second portion (43).

13. The back-contact battery according to claim 1, characterized in that, The material of the connecting conductor (4) includes silver and copper.

14. The back-contact battery according to claim 5, characterized in that, The connecting conductor (4) is disposed at the edge of at least one of the two opposite first sides close to the battery body (1).

15. A photovoltaic module, characterized in that, Comprising: The back-contact battery according to any one of claims 1 to 14; An electrical connector (7) electrically connecting the connecting conductors (4) of at least two of the back-contact batteries.

16. The photovoltaic module according to claim 15, characterized in that, A plurality of joints (6) are spaced along a first direction between the electrical connector (7) and the connecting conductor (4), and at least a part of the plurality of joints (6) is disposed on the second part (43) of the connecting conductor (4).

17. The photovoltaic module according to claim 16, wherein The number of the joints (6) provided on the same connecting conductor (4) is between 15 and 24.

18. The photovoltaic module according to claim 15, wherein The third spacing between the end of the electrical connector (7) located within the battery body (1) of the back-contact battery and the first side of the adjacent battery body (1) is between 1 and 5 millimeters.

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