CN118315371A - Back contact battery and photovoltaic module - Google Patents

Abstract

The embodiment of the application relates to the technical field of photovoltaics, and provides a back contact battery and a photovoltaic module, wherein the back contact battery comprises: the battery comprises a battery body, wherein a first surface of the battery body is provided with a plurality of fine grids and a plurality of main grids, and the fine grids comprise a first fine grid and a second fine grid; the plurality of main grids comprise first main grids and second main grids, each first main grid is electrically connected with the plurality of first thin grids, each second main grid is electrically connected with the plurality of second thin grids, and each main grid is correspondingly provided with a plurality of bonding pads which are arranged at intervals along the second direction; at least one first main grid is a first test main grid, at least one second main grid is a second test main grid, and in the second direction, the size of a first test pad in the first test main grid is larger than that of a first conventional pad, and the size of a second test pad in the second test main grid is larger than that of a second conventional pad. The back contact battery and the photovoltaic module provided by the embodiment of the application are at least beneficial to improving the testing accuracy of the back contact battery.

Description

Back contact battery and photovoltaic module

Technical Field

The embodiment of the application relates to the technical field of photovoltaics, in particular to a back contact battery and a photovoltaic module.

Background

In the solar photovoltaic technology, the back contact (INTERDIGITATED BACK CONTACT, IBC) battery has the most remarkable characteristics that PN junction and contact metal are both positioned on the back of the IBC battery, and the front of the IBC battery thoroughly avoids shielding of a metal grid electrode, can furthest utilize incident light, reduces optical loss and has higher short-circuit current.

The IBC battery needs to be subjected to performance test before leaving the factory, and when the IBC battery is subjected to performance test, a probe of the test equipment needs to be electrically connected with contact metal on the back surface of the IBC battery. The test process generally adopts modes such as negative pressure adsorption or compaction to enable the IBC battery piece to be in contact with the probe, so that the performance test of the IBC battery can be successfully completed.

How to accurately test the performance parameters of IBC batteries is a technical problem that needs to be solved by those skilled in the art.

Disclosure of Invention

The embodiment of the application provides a back contact battery and a photovoltaic module, which are at least beneficial to improving the testing precision of the back contact battery.

According to some embodiments of the present application, an aspect of an embodiment of the present application provides a back contact battery, including: the battery body is provided with a first surface and a second surface which are opposite; the thin grids are positioned on the first surface, the thin grids comprise first thin grids and second thin grids which extend along the first direction, the first thin grids and the second thin grids are alternately arranged along the second direction, and the polarity of the first thin grids is different from that of the second thin grids; the first main grids and the second main grids are alternately arranged along the first direction, each first main grid is electrically connected with the plurality of first thin grids along the second direction, each second main grid is electrically connected with the plurality of second thin grids, and each main grid is correspondingly provided with a plurality of bonding pads arranged at intervals along the second direction; at least one first main gate is a first test main gate, at least one bonding pad in a plurality of bonding pads corresponding to the first test main gate is a first test bonding pad, the rest bonding pads are first conventional bonding pads, at least one first conventional bonding pad is respectively arranged on two sides of the first test bonding pad along the second direction, and the size of the first test bonding pad is larger than that of the first conventional bonding pad along the second direction; at least one second main grid is a second test main grid, at least one bonding pad in a plurality of bonding pads corresponding to the second test main grid is a second test bonding pad, the rest bonding pads are second conventional bonding pads, at least one second conventional bonding pad is respectively arranged on two sides of the second test bonding pad along the second direction, and the size of the second test bonding pad along the second direction is larger than that of the second conventional bonding pad.

In some embodiments, the first test main gate is disposed adjacent to the second test main gate in a first direction.

In some embodiments, the first test pad is at least partially aligned with the second test pad in a first direction.

In some embodiments, the first test pad includes a first portion aligned with the pad of an adjacent main gate in a second direction and a second portion located at least on one side of the first portion in the second direction, the first portion for soldering with the solder strip, the second portion for contacting with the probe; the second test pad includes a third portion aligned in the second direction and aligned with the pad of the adjacent main gate in the first direction, and a fourth portion located at least on one side of the third portion in the second direction, the third portion for soldering with the solder strip, the fourth portion for contacting with the probe.

In some embodiments, the first regular pad has a size of a first size A1 in the second direction, and the size B of the first test pad satisfies the following relationship: b is more than or equal to 2×A1 and less than or equal to 0.2 and less than or equal to 2×A+0.2; in the second direction, the second normal pad has a second dimension A2, and the second test pad has a dimension C satisfying the following relationship: 2 xA2-0.2.ltoreq.C.ltoreq.2xA2+0.2.

In some embodiments, the first test pad has a size equal to the size of the first regular pad and the second test pad has a size equal to the size of the second regular pad in the first direction.

In some embodiments, a difference between the number of first regular pads located on one side of the first test pad and the number of first regular pads located on the other side of the first test pad in the second direction is less than or equal to 10; the difference between the number of second normal pads on one side of the second test pad and the number of second normal pads on the other side of the second test pad is less than or equal to 10.

In some embodiments, the first or last pad at one end of the first main gate in the second direction is a first connection pad, and the size of the first connection pad in the second direction is larger than the size of the first normal pad; the first or last pad at one end of the second main gate in the second direction is a second connection pad, and the size of the second connection pad in the second direction is larger than that of the second normal pad.

In some embodiments, the first regular pad has a size of a first size A1 in the second direction, and the size D of the first connection pad satisfies the following relationship: A1+0.2.ltoreq.D.ltoreq.A1+0.5; in the second direction, the size of the second regular pad is the first size A2, and the size E of the second connection pad satisfies the following relation: A2+0.2.ltoreq.E.ltoreq.A2+0.5.

According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a photovoltaic module, including: a battery string including a plurality of back contact batteries as in any one of the embodiments described above connected in sequence; the packaging layer covers the surface of the battery string; and the cover plate covers the surface of the packaging layer far away from the battery strings.

The technical scheme provided by the embodiment of the application has at least the following advantages:

In the back contact battery provided by the embodiment of the application, the first surface of the battery body is provided with a plurality of fine grids for collecting and transmitting photo-generated carriers so as to realize the electric energy conversion of the back contact battery, wherein the fine grids comprise a first fine grid and a second fine grid, the first fine grid is one of an anode and a cathode, and the second fine grid is the other of the anode and the cathode; the first surface is also provided with a plurality of main grids, wherein the main grids comprise a first main grid and a second main grid, the first main grid is connected with the plurality of first fine grids, the second main grid is connected with the plurality of second fine grids, the first main grid is used for collecting carriers corresponding to the first fine grids, and the second main grid is used for collecting carriers corresponding to the second fine grids. Each main grid is correspondingly provided with a plurality of bonding pads, the bonding pads can be used for welding the main grids and other connecting parts, at least one first main grid is a first test main grid, at least one second main grid is a second test main grid, the first test main grid and the second test main grid are connected with probes in the process of back contact battery testing, at least one bonding pad in the plurality of bonding pads corresponding to the first test main grid is a first test bonding pad, the size of the first test bonding pad is larger than that of other first conventional bonding pads, at least one bonding pad in the plurality of bonding pads corresponding to the second test main grid is a second test bonding pad, and the size of the second test bonding pad is larger than that of the second conventional bonding pad. In addition, because the size of the first test pad and the size of the second test pad are larger, when the back contact battery is subjected to current test and voltage test, the current test probes and the voltage test probes can share the same group of the first test pad and the second test pad to form a corresponding current test loop and a corresponding voltage test loop respectively, so that the test efficiency of the back contact battery is improved.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise; in order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the drawings required for the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

Fig. 1 is a top view corresponding to a first surface of a back contact battery according to an embodiment of the present application;

fig. 2 is a top view corresponding to a first surface of another back contact battery according to an embodiment of the present application;

fig. 3 is a schematic cross-sectional structure of the back contact cell in fig. 1 or fig. 2 along the SS1 direction;

FIG. 4 is a schematic diagram of a partial enlarged structure of two first test pads and adjacent pads according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a partial enlarged structure of a first test pad and a first conventional pad according to an embodiment of the present application;

Fig. 6 is a corresponding top view of a first side of a back contact battery according to another embodiment of the present application.

Detailed Description

In the process of testing the IBC battery, as the probe is arranged on the back of the IBC battery, the contact condition of the back probe and the back main grid line of the IBC battery cannot be observed intuitively, and the alignment condition of the back probe and the back main grid line cannot be determined accurately. Because of the special structure of the IBC battery, if the probe row cannot be aligned with the main grid line, it is highly likely that the probe row will press against the adjacent thin grid line, and the adjacent thin grid line has both the positive thin grid line and the negative thin grid line, which may cause an abnormality to the test.

The embodiment of the application provides a back contact battery and a photovoltaic module, wherein in the back contact battery, a plurality of thin grids are arranged on a first surface of a battery body and used for collecting and transmitting photo-generated carriers so as to realize electric energy conversion of the back contact battery, wherein the thin grids comprise a first thin grid and a second thin grid, the first thin grid is one of an anode and a cathode, and the second thin grid is the other of the anode and the cathode; the first surface is also provided with a plurality of main grids, wherein the main grids comprise a first main grid and a second main grid, the first main grid is connected with the plurality of first fine grids, the second main grid is connected with the plurality of second fine grids, the first main grid is used for collecting carriers corresponding to the first fine grids, and the second main grid is used for collecting carriers corresponding to the second fine grids. Each main grid is correspondingly provided with a plurality of bonding pads, the bonding pads can be used for welding the main grids and other connecting parts, at least one first main grid is a first test main grid, at least one second main grid is a second test main grid, the first test main grid and the second test main grid are connected with probes in the process of back contact battery testing, at least one bonding pad in the plurality of bonding pads corresponding to the first test main grid is a first test bonding pad, the size of the first test bonding pad is larger than that of other first conventional bonding pads, at least one bonding pad in the plurality of bonding pads corresponding to the second test main grid is a second test bonding pad, and the size of the second test bonding pad is larger than that of the second conventional bonding pad. In addition, because the size of the first test pad and the size of the second test pad are larger, when the back contact battery is subjected to current test and voltage test, the current test probes and the voltage test probes can share the same group of the first test pad and the second test pad to form a corresponding current test loop and a corresponding voltage test loop respectively, so that the test efficiency of the back contact battery is improved.

In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the positional or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "dimension", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the positional or positional relationship shown in the drawings, and are merely for convenience of description and simplification of the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore are not to be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like should be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to specific circumstances.

In the drawings corresponding to the embodiments of the present application, thicknesses and areas of layers are exaggerated for better understanding and convenience of description. When an element (e.g., a layer, film, region, or substrate) is referred to as being "on" or "on" another element, it can be "directly on" the other element or be present between the two elements. Conversely, when it is described that one component is formed on or provided with another component surface, then it is meant that there is no third component between the two components. Further, when it is described that one component is "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a partial edge of the entire surface.

In the description of embodiments of the present application, when a certain component "includes" another component, the other component is not excluded unless otherwise stated, and the other component may be further included. In addition, when an element such as a layer, film, region, or panel is referred to as being "on/on" another element, it can be "directly on" the other element (i.e., no other element is present between the two surfaces of the other element), or another element can be present therebetween. In addition, when a layer, film, region, plate, etc., is "directly on" another element, or when a layer, film, region, plate, etc., is on the surface of another element, it means that no other element is located therebetween.

The terminology used in the description of the various described embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the components" are also intended to include the plural forms unless the context clearly indicates otherwise. Wherein the components include layers, films, regions, or plates.

Embodiments of the present application will be described in detail below with reference to the attached drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the present application. The claimed application may be practiced without these specific details and with various changes and modifications based on the following embodiments.

Fig. 1 is a top view corresponding to a first surface of a back contact battery according to an embodiment of the present application; fig. 2 is a top view corresponding to a first surface of another back contact battery according to an embodiment of the present application; fig. 3 is a schematic cross-sectional structure of the back contact cell in fig. 1 or fig. 2 along the SS1 direction.

Referring to fig. 1 to 3, the back contact battery includes: a battery body 100, a plurality of fine grids 200, and a plurality of main grids 300, the battery body 100 having opposite first and second faces 101 and 102; the plurality of fine grids 200 and the plurality of main grids 300 are located on the first face 101 of the battery body 100. The plurality of fine gratings 200 include first fine gratings 201 and second fine gratings 202 each extending in a first direction X, the first fine gratings 201 and the second fine gratings 202 being alternately arranged in a second direction Y, and a polarity of the first fine gratings 201 being different from a polarity of the second fine gratings 202. The plurality of main grids 300 include first main grids 301 and second main grids 302 each extending along a second direction Y, the first main grids 301 and the second main grids 302 being alternately arranged along the first direction X, each first main grid 301 being electrically connected to the plurality of first thin grids 201 along the second direction Y, each second main grid 302 being electrically connected to the plurality of second thin grids 202, each main grid 300 corresponding to having a plurality of pads 303 arranged at intervals along the second direction Y. At least one first main gate 301 is a first test main gate 311, at least one pad 303 of the plurality of pads 303 corresponding to the first test main gate 311 is a first test pad 313, the remaining pads 303 are first regular pads 323, at least one first regular pad 323 is respectively disposed on two sides of the first test pad 313 along the second direction Y, and a size of the first test pad 313 along the second direction Y is larger than a size of the first regular pad 323. At least one second main gate 302 is a second test main gate 312, at least one pad 303 of the plurality of pads 303 corresponding to the second test main gate 312 is a second test pad 333, the rest of pads 303 are second regular pads 343, at least one second regular pad 343 is respectively arranged on two sides of the second test pad 333 along the second direction Y, and the size of the second test pad 333 is larger than that of the second regular pad 343 along the second direction Y.

In the back contact battery provided by the embodiment of the application, the first surface 101 of the battery body 100 is provided with a plurality of thin grids 200 for collecting and transmitting photo-generated carriers, so as to realize the electric energy conversion of the back contact battery, wherein the thin grids 200 comprise a first thin grid 201 and a second thin grid 202, the first thin grid 201 is one of positive electrode and negative electrode, and the second thin grid 202 is the other of positive electrode and negative electrode; the first surface 101 is further provided with a plurality of main grids 300, wherein the main grids 300 comprise a first main grid 301 and a second main grid 302, the first main grid 301 is connected with the plurality of first fine grids 201, the second main grid 302 is connected with the plurality of second fine grids 202, the first main grid 301 is used for collecting corresponding carriers on the first fine grids 201, and the second main grid 302 is used for collecting corresponding carriers on the second fine grids 202. Each main gate 300 is correspondingly provided with a plurality of bonding pads 303, the bonding pads 303 can be used for welding the main gate 300 and other connecting components, at least one first main gate 301 is a first testing main gate 311, at least one second main gate 302 is a second testing main gate 312, the first testing main gate 311 and the second testing main gate 312 are connected with probes in the process of back contact battery testing, at least one bonding pad 303 in the plurality of bonding pads 303 corresponding to the first testing main gate 311 is a first testing bonding pad 313, the size of the first testing bonding pad 313 is larger than that of other first conventional bonding pads 323, at least one bonding pad 303 in the plurality of bonding pads 303 corresponding to the second testing main gate 312 is a second testing bonding pad 333, and the size of the second testing bonding pad 333 is larger than that of the second conventional bonding pad 343, so that the probes can form a testing loop through electric contact with the first testing bonding pad 313 and the second testing bonding pad 333, and the accuracy of alignment of the probes with the first testing bonding pad 313 and the second testing bonding pad 333 is improved. In addition, since the sizes of the first test pad 313 and the second test pad 333 are larger, when the back contact battery is subjected to the current test and the voltage test, the current test probe and the voltage test probe can share the same group of the first test pad 313 and the second test pad 333 to form a corresponding current test loop and a corresponding voltage test loop, respectively, thereby being beneficial to improving the test efficiency of the back contact battery.

In some embodiments, referring to fig. 3, the battery body 100 may include a substrate 110, a first passivation layer 111 and a second passivation layer 112, the first passivation layer 111 being located at one side surface of the substrate 110, the second passivation layer 112 being located at a surface of the substrate 110 remote from the first passivation layer 111, the surface of the first passivation layer 111 remote from the substrate 110 being the first face 101, and the surface of the second passivation layer 112 remote from the substrate 110 being the second face 102. The first passivation layer 111 and the substrate 110 further include a first doped layer 113 and a second doped layer 114 disposed at intervals, the first thin gate 201 is in electrical contact with the first doped layer 113 through the first passivation layer 111, and the second thin gate 202 is in electrical contact with the second doped layer 114 through the first passivation layer 111, and the conductivity type of the doping ions in the first doped layer 113 is different from the conductivity type of the doping ions in the second doped layer 114.

In some embodiments, the material of the substrate 110 may be an elemental semiconductor material. For example, the elemental semiconductor material may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

In some embodiments, the substrate 110 may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which may be any of v group elements such As phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element, and arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, and the P-type doped element may be any one of group iii elements such as boron (B) element, aluminum (Al) element, gallium (Ga) element, and indium (In) element.

In some embodiments, the surface of the substrate 110 contacting the second passivation layer 112 may have a textured structure, such as a pyramid structure, so that the textured structure may enhance the absorption and utilization of the incident light by the substrate 110, thereby advantageously improving the light conversion efficiency of the back contact cell.

In some embodiments, the second surface is used as a light receiving surface for receiving incident light, and the first surface is used as a backlight surface. In some embodiments, the first surface and the second surface may both be light-receiving surfaces, and both may be used to receive incident light.

In some embodiments, the conductivity type of the doped ions in the first doped layer 113 is the same as the conductivity type of the doped ions in the substrate 110, and the conductivity type of the doped ions in the second doped layer 114 is different from the conductivity type of the doped ions in the substrate 110, so that the second doped layer 114 and the substrate 110 form a PN junction to effectively shunt carriers. In some embodiments, the conductivity type of the doped ions in the first doped layer 113 may be different from the conductivity type of the doped ions in the substrate 110, and the conductivity type of the doped ions in the second doped layer 114 may be the same as the conductivity type of the doped ions in the substrate 110, so that the first doped layer 113 and the substrate 110 form a PN junction to effectively shunt carriers.

In fig. 3, the first doped layer 113 and the second doped layer 114 are both located on the surface of the substrate 110. In some embodiments, when the conductivity type of the doping ions in the first doping layer 113 is the same as the conductivity type of the doping ions in the substrate 110, the first doping layer 113 may also be located in the substrate 110; or the second doped layer 114 may also be located within the substrate 110 when the conductivity type of the dopant ions within the second doped layer 114 is the same as the conductivity type of the dopant ions within the substrate 110.

In some embodiments, the material of the first passivation layer 111 may include at least one of aluminum oxide, silicon nitride, or silicon oxynitride. The first passivation layer 111 may have a single-layer structure or a stacked-layer structure, and for example, the single-layer structure may be a single-layer aluminum oxide film layer, a single-layer silicon nitride film layer, or a single-layer silicon oxynitride film layer; the laminated structure can be formed by laminating at least two layers of aluminum oxide film layers, silicon nitride film layers or silicon oxynitride film layers.

In some embodiments, the material of the second passivation layer 112 may include at least one of aluminum oxide, silicon nitride, or silicon oxynitride. The second passivation layer 112 may have a single-layer structure or a stacked-layer structure, for example, a single-layer aluminum oxide film layer, a single-layer silicon nitride film layer, or a single-layer silicon oxynitride film layer; the laminated structure can be formed by laminating at least two layers of aluminum oxide film layers, silicon nitride film layers or silicon oxynitride film layers.

In some embodiments, the material of the main gate 300 may include one or more of aluminum, silver, gold, nickel, molybdenum, or copper.

In some embodiments, the material of the fine gate 200 may include one or more of aluminum, silver, gold, nickel, molybdenum, or copper.

In some embodiments, the material of the pads 303 may include one or more of aluminum, silver, gold, nickel, molybdenum, or copper.

In some embodiments, referring to fig. 1, in the first direction X, the pads 303 corresponding to the adjacent main gates 300 may be disposed offset from each other; alternatively, referring to fig. 2, the pads 303 corresponding to adjacent main gates 300 may be disposed in alignment with each other in the first direction X. It is understood that the positions and the number of the pads 303 may be set according to the positions and the number of the main gates 300 and the corresponding thin gates 200, so as to avoid the problem of electric leakage between the main gates 300 and the thin gates 200 with different polarities.

In some embodiments, the first test main gate 311 is disposed adjacent to the second test main gate 321 in the first direction X. It will be appreciated that when there are other main gates 300 between the first and second main gates 311 and 321, carriers in the back contact cell need to move between the first and second main gates 311 and 321 across the corresponding regions of the other main gates 300 in the substrate 110, so that the potential difference between the first and second main gates 311 and 321 as measured may be divided due to the self-resistance in the substrate 110. When the first test main gate 311 and the second test main gate 321 are adjacently disposed, the potential difference between the first test main gate 311 and the second test main gate 321 is closer to the potential difference between the positive electrode and the negative electrode in the whole back contact battery, so that the test accuracy of the back contact battery can be improved.

In some embodiments, the first test pad 313 is at least partially aligned with the second test pad 333 in the first direction X. When the back contact battery is tested, the positive electrode probe and the negative electrode probe are both positioned on the back surface of the back contact battery, and the position deviation of the probes easily causes that the probes cannot contact the corresponding bonding pads 303 or contact the thin grids 200 with opposite polarities, so that the test is abnormal. When the first test pad 313 and the second test pad 333 are at least partially aligned along the first direction X, the corresponding positive electrode probe and negative electrode probe can be aligned along the first direction X, which is favorable for aligning the relative positions of the positive electrode probe and the negative electrode probe, and further, the probe and the corresponding pad 303 are more convenient to align, which is favorable for improving the accuracy of the contact position of the probe and the pad 303, so as to improve the accuracy and efficiency of the back contact battery test.

Fig. 4 is a schematic diagram of a partial enlarged structure of two first test pads and adjacent pads according to an embodiment of the application. In fig. 4, only the main gate is shown, and the thin gate is not shown for convenience of explanation.

In some embodiments, referring to fig. 4, the first test pad 313 may include a first portion 314 aligned with the pad 303 of the adjacent second main gate 302 along the second direction Y and a second portion 315 aligned with the first portion 314 along the first direction X, the second portion 315 being located at least on one side of the first portion 314 along the second direction Y, the first portion 314 being for soldering with a solder ribbon, the second portion 315 being for contact with a probe. During the test, the probe needs to be abutted against the first test pad 313 to facilitate the current transmission, however, the probe may cause local deformation of the first test pad 313 during the abutment, for example, a hole or a recess is generated on the surface of the first test pad 313, so that in the subsequent process of welding the solder strip, the problem of bubbles in the solder strip is caused after the solder strip covers the first test pad 313, and the bubbles between the solder strip and the first test pad 313 easily cause an increase in the transmission resistance between the first test main grid 311 and the solder strip, thereby reducing the efficiency of the back contact battery. By dividing the first test pad 313 into the first portion 314 and the second portion 315, it is beneficial to keep the surface of the first portion 314 free from the influence of the probe, so as to keep the first portion 314 and the solder paste to have a complete contact area, avoid the problem of increasing the contact resistance between the first test pad 313 and the solder strip due to air bubbles, and be beneficial to keeping the back contact battery to have better performance after testing.

In some embodiments, referring to (a) in fig. 4, the second portion 315 may be located only on one side of the first portion 314 in the second direction Y; or referring to (b) of fig. 4, the second portion 315 may be located at both sides of the first portion 314 in the second direction Y.

Similarly, in some embodiments, the second test pad may include a third portion aligned with the pad of an adjacent first main gate in the first direction and a fourth portion located at least on one side of the third portion in the second direction, the third portion for soldering with the solder strip, the fourth portion for contacting with the probe. In the test process, the probe needs to be abutted against the second test pad so as to facilitate current transmission, however, the probe may cause local deformation of the second test pad in the abutting process, for example, holes or pits are formed on the surface of the second test pad, so that in the subsequent process of welding the solder strip, bubbles are formed in the solder strip after the solder strip covers the second test pad, and the bubbles between the solder strip and the second test pad easily cause an increase in transmission resistance between the second test main grid and the solder strip, thereby reducing the efficiency of the back contact battery. The second test pad is divided into the third part and the fourth part, so that the surface of the third part is not influenced by the probe, the third part and the solder paste are kept to have complete contact area, the problem of contact resistance increase between the second test pad and the solder strip caused by air bubbles is avoided, and the back contact battery is kept to have better performance after testing.

In some embodiments, the third portion may be located only on one side of the fourth portion in the second direction; or the third portion may be located on both sides of the fourth portion in the second direction.

Fig. 5 is a schematic diagram of a partial enlarged structure of a first test pad and a first conventional pad according to an embodiment of the present application.

In some embodiments, referring to fig. 5, in the second direction Y, the size of the first conventional pad 323 is a first size A1, and the size B of the first test pad 313 satisfies the following relationship: 2×a1-0.2.ltoreq.b.ltoreq.2× a1+0.2, for example, the size B of the first test pad 313 may be 2×a1-0.2, 2×a1-0.1, 2×a1, 2×a1+0.1, or 2×a1+0.2. It will be appreciated that the size of the first test pad 313 is larger than the size of the first regular pad 323, so that the first test pad 313 has enough area for contact with the probe, and the size difference between the size of the first test pad 313 and the size difference between the first regular pad 323 should be within a proper range, so as to avoid the problem that the size of the first test pad 313 is oversized and the adjacent second fine grid 202 leaks, and also to be beneficial to saving the use cost of the slurry.

In some embodiments, the first conventional pad 323 may have a size of 0.3mm to 1.1mm in the second direction Y, for example, the first size A1 may be 0.3mm, 0.4mm, 0.5mm, 0.7mm, 0.8mm, 1mm, 1.1mm, or the like.

In some embodiments, in the second direction Y, the size of the second regular pad 343 is a second size A2, and the size C of the second test pad 333 satisfies the following relationship: 2×A2-0.2.ltoreq.C.ltoreq.2× A2+0.2, for example, the size C of the second test pad 333 may be 2×A1-0.2, 2×A1-0.1, 2×A1, 2×A1+0.1, or 2×A1+0.2. It will be appreciated that the size of the second test pad 333 is larger than the size of the second conventional pad 343, so that the second test pad 333 may have enough area for contact with the probe, and the size difference between the second test pad 333 and the second conventional pad 343 needs to be within a proper range to avoid the problem that the second test pad 333 is oversized and the adjacent first fine grid 201 leaks, and also to facilitate saving of the use cost of the slurry.

In some embodiments, the second test pad 333 may have a size of 0.3mm to 1.1mm in the second direction Y by the second size A2, for example, the second size A2 may be 0.3mm, 0.4mm, 0.5mm, 0.7mm, 0.8mm, 1mm, 1.1mm, or the like.

In some embodiments, the size of the first regular pad 323 is equal to the size of the second regular pad 343 in the second direction Y, so that screen printing may be facilitated, and a problem of non-uniform filling of the first regular pad 323 or the second regular pad 343 during printing due to a difference in size between the first regular pad 323 and the second regular pad 343 may be avoided.

In some embodiments, the size of the first conventional pad 323 and the size of the second conventional pad 343 may also be unequal in the second direction Y.

In some embodiments, in the second direction Y, the size of the first regular pad 323 is equal to the size of the second regular pad 343, and the size of the pad 303 corresponding to the other first and second main gates 301 and 302 is equal. That is, of all the pads 303, only the first test pad 313 and the second test pad 333 have a size larger than that of the other pads 303 in the second direction Y, which may be advantageous for screen printing, avoiding the problem of non-uniform printing of the pads 303 due to excessive variation in the size of the pads 303.

In some embodiments, the size of the first regular pad 323 may be unequal to the size of the corresponding pad 303 of the other first and second main gates 301 and 302 in the second direction Y. In some embodiments, the second regular pad 343 may have a size not equal to the size of the corresponding pad 303 of the other first and second main gates 301 and 302 in the second direction Y.

In some embodiments, the size of the first test pad 313 is equal to the size of the second test pad 333 in the second direction Y, which may be advantageous for screen printing, so as to avoid the problem of uneven filling of the first test pad 313 or the second test pad 333 during printing due to the size difference between the first test pad 313 and the second test pad 333.

In some embodiments, the size of the first test pad 313 and the size of the second test pad 333 may also be unequal in the second direction Y.

In some embodiments, the size of the first test pad 313 is equal to the size of the first regular pad 323 in the first direction X. That is, the first test pad 313 is lengthened only in the second direction Y, and the dimension in the first direction X is unchanged compared with the first conventional pad 323, so that the problem of leakage between the first test pad 313 and the adjacent second fine gate 202 can be avoided, which is beneficial to improving the stability of the back contact battery.

In some embodiments, the size of the first test pad 313 may be different from the size of the first conventional pad 323 in the first direction X.

In some embodiments, the size of the second test pad 333 is equal to the size of the second regular pad 343 in the first direction X. That is, the second test pad 333 is lengthened only in the second direction Y, and the dimension in the first direction X is unchanged compared to the second conventional pad 343, so that the problem of leakage between the second test pad 333 and the adjacent first fine gate 201 can be avoided, which is beneficial to improving the stability of the back contact battery.

In some embodiments, the size of the second test pad 333 may be different from the size of the second regular pad 343 in the first direction X.

In some embodiments, the size of the first regular pad 323 is equal to the size of the second regular pad 343 in the first direction X, and the size of the pad 303 corresponding to the other first and second main gates 301 and 302 is equal. That is, of all the pads 303, only the first test pad 313 and the second test pad 333 are increased in size in the second direction Y, so that it is possible to facilitate screen design and printing, and to avoid the problem of non-uniform printing of the pads 303 due to excessive variation in the size of the pads 303.

In some embodiments, the size of the first regular pad 323 may be unequal to the size of the corresponding pad 303 of the other first and second main gates 301 and 302 in the first direction X. In some embodiments, the size of the second regular pad 343 may not be equal to the size of the corresponding pads 303 of the other first and second main gates 301 and 302 in the first direction X.

In fig. 1 and 2, the number of the corresponding first test pads 313 on the first test main gate 311 is 1, and the number of the corresponding second test pads 333 on the second test main gate 321 is 1. In some embodiments, the number of corresponding first test pads 313 on the first test main gate 311 may be 2,3, or 5. In some embodiments, the number of corresponding second test pads 333 on the second test main gate 321 may be 2,3, or 5.

In fig. 1 and 2, the number of the first test main gates 311 on a single back contact cell is taken as one, and the number of the second test main gates 321 is taken as one as an example. In some embodiments, the number of first test main gates 311 on a single back contact cell may also be 2,4, 7, etc. In some embodiments, the number of second test masters 321 may be 2,4, 7, or the like. The number of the first test main gates 311 and the number of the second test main gates 321 may be equal or unequal.

In some embodiments, the difference between the number of the first regular pads 323 located at one side of the first test pad 313 and the number of the first regular pads 323 located at the other side of the first test pad 313 in the second direction Y is less than or equal to 10, for example, may be 10, 8, 7, 5, 4, 2, or 1, etc. That is, for the plurality of pads 303 of the first test main gate 311 aligned along the second direction Y, the first test pad 313 is located at a position relatively centered in the length direction of the first test main gate 311, so that distances from the first test pad 313 to two ends of the first test main gate 311 are similar, so that carriers at two ends of the first test main gate 311 can reach the first test pad 313 as soon as possible and be collected by the probe, thereby being beneficial to reducing test errors.

In some embodiments, the difference between the number of second normal pads 343 located at one side of the second test pad 333 and the number of second normal pads 343 located at the other side of the second test pad 333 in the second direction Y is less than or equal to 10, for example, may be 10, 8, 7, 5, 4, 2, or 1, etc. That is, for the plurality of pads 303 of the second test main gate 321 aligned along the second direction Y, the second test pad 333 is located at a position relatively centered in the length direction of the second test main gate 321, so that the distances from the second test pad 333 to the two ends of the second test main gate 321 are similar, which is beneficial for carriers at the two ends of the second test main gate 321 to reach the second test pad 333 and be collected by the probe as soon as possible, thereby being beneficial for reducing test errors.

Fig. 6 is a corresponding top view of a first side of a back contact battery according to another embodiment of the present application.

In some embodiments, the first or last pad 303 at one end of the first main gate 301 in the second direction Y is a first connection pad 351, and the size of the first connection pad 351 is larger than the size of the first regular pad 323 in the second direction Y; the first or last pad 303 at one end of the second main gate 302 in the second direction Y is a second connection pad 352, and the size of the second connection pad 352 in the second direction Y is larger than that of the second normal pad 343.

The first connection pads 351 are used for converging the plurality of first main grids 301, the second connection pads 352 are used for converging the plurality of second main grids 302, for example, the plurality of first converging probes can be respectively electrically contacted with the first connection pads 351 positioned at the end parts of the first main grids 301, and carriers in the plurality of first main grids 301 are converged into the first test pads 313 corresponding to the first test main grids 311; the plurality of second bus probes are respectively in electrical contact with the second connection pads 352 positioned at the end parts of the second main grids 302, carriers in the plurality of second main grids 302 are converged into the second test pads 333 corresponding to the second test main grids 321, the first test pads 313 and the second test pads 333 are connected into corresponding test loops through the test probes for testing, and the first connection pads 351 are larger in size and positioned at the end parts of the first main grids 301, and the second connection pads 352 are larger in size and positioned at the end parts of the second main grids 302, so that alignment of the first bus probes and the second bus probes can be facilitated, and the test precision is improved.

In some embodiments, the size of the first regular pad 323 is the first size A1 in the second direction Y, and the size D of the first connection pad 351 satisfies the following relationship: a1+0.2.ltoreq.d.ltoreq.a1+0.5, for example, the size D of the first connection pad 351 may be a1+0.2, a1+0.3, a1+0.4, a1+0.5, or the like.

In some embodiments, the second regular pad 343 has a size of the first size A2 in the second direction Y, and the size E of the second connection pad 352 satisfies the following relationship: a2+0.2.ltoreq.e.ltoreq.a2+0.5, for example, the size E of the second connection pad 352 may be a1+0.2, a1+0.3, a1+0.4, a1+0.5, or the like.

It will be appreciated that the size of the first connection pad 351 is larger than the size of the first regular pad 323, so that the first connection pad 351 has enough area for contact with the probe, and the size difference between the first connection pad 351 and the first regular pad 323 needs to be within a proper range to avoid the problem of the oversized first connection pad 351 and the leakage of the adjacent second fine grid 202, and also to facilitate the saving of the use cost of the slurry. Similarly, the difference in the size of the second connection pad 352 and the second conventional pad 343 needs to be within a proper range so that the second connection pad 352 has a sufficient area for contact with the probe while avoiding the problem of the second connection pad 352 being oversized and leakage from the adjacent first fine gate 201 and saving the use cost of the paste.

In the back contact battery provided by the embodiment of the application, the first surface 101 of the battery body 100 is provided with a plurality of thin grids 200 for collecting and transmitting photo-generated carriers, so as to realize the electric energy conversion of the back contact battery, wherein the thin grids 200 comprise a first thin grid 201 and a second thin grid 202, the first thin grid 201 is one of positive electrode and negative electrode, and the second thin grid 202 is the other of positive electrode and negative electrode; the first surface 101 is further provided with a plurality of main grids 300, wherein the main grids 300 comprise a first main grid 301 and a second main grid 302, the first main grid 301 is connected with the plurality of first fine grids 201, the second main grid 302 is connected with the plurality of second fine grids 202, the first main grid 301 is used for collecting corresponding carriers on the first fine grids 201, and the second main grid 302 is used for collecting corresponding carriers on the second fine grids 202. Each main gate 300 is correspondingly provided with a plurality of bonding pads 303, the bonding pads 303 can be used for welding the main gate 300 and other connecting components, at least one first main gate 301 is a first testing main gate 311, at least one second main gate 302 is a second testing main gate 312, the first testing main gate 311 and the second testing main gate 312 are connected with probes in the process of back contact battery testing, at least one bonding pad 303 in the plurality of bonding pads 303 corresponding to the first testing main gate 311 is a first testing bonding pad 313, the size of the first testing bonding pad 313 is larger than that of other first conventional bonding pads 323, at least one bonding pad 303 in the plurality of bonding pads 303 corresponding to the second testing main gate 312 is a second testing bonding pad 333, and the size of the second testing bonding pad 333 is larger than that of the second conventional bonding pad 343, so that the probes can form a testing loop through electric contact with the first testing bonding pad 313 and the second testing bonding pad 333, and the accuracy of alignment of the probes with the first testing bonding pad 313 and the second testing bonding pad 333 is improved. In addition, since the sizes of the first test pad 313 and the second test pad 333 are larger, when the back contact battery is subjected to the current test and the voltage test, the current test probe and the voltage test probe can share the same group of the first test pad 313 and the second test pad 333 to form a corresponding current test loop and a corresponding voltage test loop, respectively, thereby being beneficial to improving the test efficiency of the back contact battery.

Correspondingly, another embodiment of the present application further provides a photovoltaic module, including: a battery string including a plurality of back contact batteries as in any one of the embodiments described above connected in sequence; the packaging layer covers the surface of the battery string; and the cover plate covers the surface of the packaging layer far away from the battery strings. The same or corresponding parts as those of the previous embodiment may be referred to for corresponding description of the previous embodiment, and detailed description thereof will be omitted.

In some embodiments, adjacent back contact cells may be connected by a first solder strip and a second solder strip, for example, for one back contact cell, a first main grid of the back contact cell is connected by a first solder strip to a second main grid of another back contact cell on an adjacent side, and the second main grid of the back contact cell is connected by a second solder strip to a first main grid of another back contact cell on an adjacent side, such that a plurality of back contact cells are serially connected in sequence.

In some embodiments, the material of the encapsulation layer may be an organic encapsulation film such as an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film, or a polyvinyl butyral (PVB) film.

In some embodiments, the cover plate may be a glass cover plate, a plastic cover plate, or the like having a light transmitting function. In some embodiments, the surface of the cover plate facing the encapsulation layer may be a concave-convex surface, thereby increasing the utilization of incident light.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the application and that various changes in form and details may be made therein without departing from the spirit and scope of the application. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the application, and the scope of the application should be assessed accordingly to that of the appended claims.

Claims (10)

1. A back contact battery, comprising:

A battery body having opposing first and second faces;

The thin grids are positioned on the first surface, the thin grids comprise a first thin grid and a second thin grid which extend along a first direction, the first thin grid and the second thin grid are alternately arranged along a second direction, and the polarity of the first thin grid is different from that of the second thin grid;

A plurality of main grids positioned on the first surface, wherein the plurality of main grids comprise a first main grid and a second main grid which extend along the second direction, the first main grid and the second main grid are alternately arranged along the first direction, each first main grid is electrically connected with a plurality of first thin grids along the second direction, each second main grid is electrically connected with a plurality of second thin grids, and each main grid is correspondingly provided with a plurality of bonding pads which are arranged along the second direction at intervals;

At least one first main gate is a first test main gate, at least one bonding pad of the plurality of bonding pads corresponding to the first test main gate is a first test bonding pad, the rest bonding pads are first conventional bonding pads, at least one first conventional bonding pad is respectively arranged on two sides of the first test bonding pad along the second direction, and the size of the first test bonding pad is larger than that of the first conventional bonding pad along the second direction;

At least one second main gate is a second test main gate, at least one of the plurality of bonding pads corresponding to the second test main gate is a second test bonding pad, the rest bonding pads are second conventional bonding pads, at least one second conventional bonding pad is respectively arranged on two sides of the second test bonding pad along the second direction, and the size of the second test bonding pad is larger than that of the second conventional bonding pad along the second direction.

2. The back contact battery of claim 1, wherein the first test main gate is disposed adjacent to the second test main gate in the first direction.

3. The back contact battery of claim 2, wherein the first test pad is at least partially aligned with the second test pad in the first direction.

4. The back contact battery of claim 1, wherein the back contact battery is configured to provide a back contact,

The first test pad includes a first portion aligned with the pad adjacent to the main gate in the first direction and a second portion located at least on one side of the first portion in the second direction, the first portion for soldering with a solder strip, the second portion for contacting with a probe;

the second test pad includes a third portion aligned with the pad adjacent to the main gate in the second direction and a fourth portion at least on one side of the third portion in the second direction for soldering with the solder strip, the fourth portion for contacting with the probe.

5. The back contact battery of claim 1, wherein the first regular pad has a first dimension A1 in the second direction, and the first test pad has a dimension B satisfying the following relationship: b is more than or equal to 2×A1 and less than or equal to 0.2 and less than or equal to 2×A+0.2; in the second direction, the second normal pad has a second size A2, and the second test pad has a size C satisfying the following relationship: 2 xA2-0.2.ltoreq.C.ltoreq.2xA2+0.2.

6. The back contact battery of claim 1, wherein the first test pad has a size equal to the size of the first regular pad and the second test pad has a size equal to the size of the second regular pad in the first direction.

7. The back contact battery of claim 1, wherein a difference between the number of the first regular pads located on one side of the first test pad and the number of the first regular pads located on the other side of the first test pad in the second direction is less than or equal to 10; the difference between the number of the second normal pads located at one side of the second test pad and the number of the second normal pads located at the other side of the second test pad is less than or equal to 10.

8. The back contact battery of claim 1, wherein the back contact battery is configured to provide a back contact,

A first or last one of the pads at one end of the first main gate in the second direction is a first connection pad, and the size of the first connection pad in the second direction is larger than that of the first regular pad; the first or last one of the pads at one end of the second main gate in the second direction is a second connection pad, and the second connection pad has a size larger than that of the second normal pad in the second direction.

9. The back contact battery of claim 8, wherein the first regular pad has a first dimension A1 in the second direction, and the first connection pad has a dimension D satisfying the following relationship: A1+0.2.ltoreq.D.ltoreq.A1+0.5; in the second direction, the second normal pad has a size of a first size A2, and the second connection pad has a size E satisfying the following relation: A2+0.2.ltoreq.E.ltoreq.A2+0.5.

10. A photovoltaic module, comprising:

A battery string comprising a plurality of back-contact batteries according to any one of claims 1 to 9 connected in sequence;

an encapsulation layer covering a surface of the battery string;

and the cover plate covers the surface of the packaging layer far away from the battery string.