Disclosure of Invention
The technical problem to be solved by the embodiment of the invention is to provide a combined printing method of a battery piece and the battery piece, and solve the problems of overlarge height difference between a main grid and an auxiliary grid and low current transmission efficiency while improving the aspect ratio of the auxiliary grid.
In order to solve the above problem, an embodiment of the present invention provides a method for printing a combination of battery pieces, including: providing a battery piece substrate; printing a plurality of main grids on the battery piece substrate, wherein the main grids are parallel to each other, and a plurality of first notches arranged at intervals are arranged on two sides of each main grid in the extending direction of the main grids; and then printing on the battery piece substrate to form a plurality of auxiliary grids, wherein the extension direction of each auxiliary grid is perpendicular to the extension direction of each main grid, the height of each auxiliary grid is greater than that of each main grid in the direction perpendicular to the battery piece substrate, each auxiliary grid is at least positioned between every two adjacent main grids, and two ends of each auxiliary grid are respectively filled with one first notch of every two adjacent main grids.
In addition, the step of printing and forming a plurality of main grids on the battery piece substrate comprises the following steps: adopt first screen printing figure to form the main grid, first screen printing figure includes a plurality of edges the first rectangular form figure that the first direction of battery piece base plate extends, rectangular form figure is parallel to each other, just the both sides of rectangular form figure all have a plurality of second breachs that set up at an interval each other, the second breach is used for printing on the battery piece base plate first breach.
In addition, the auxiliary grid comprises a bottom layer auxiliary grid and a top layer auxiliary grid; the step of printing a plurality of secondary grids on the battery piece substrate comprises the following steps: forming the bottom layer secondary grid by adopting a second screen printing pattern, wherein the second screen printing pattern comprises a plurality of second long strip patterns extending along a second direction of the battery sheet substrate, the second direction is perpendicular to the first direction, the second long strip patterns are arranged in a regular array manner, and the orthographic projection of the second long strip patterns on the battery sheet substrate covers the orthographic projection of the second gaps on the battery sheet substrate; and adopting a third screen printing pattern to form the top layer auxiliary grid on one side of the bottom layer auxiliary grid far away from the battery sheet substrate, wherein the third screen printing pattern comprises a plurality of third long strip patterns extending along the second direction, the third long strip patterns are arranged in a regular array manner, and the orthographic projection of the third long strip patterns on the battery sheet substrate is positioned in the orthographic projection of the second long strip patterns on the battery sheet substrate.
In addition, in the first direction, the width of the second long stripe pattern is greater than the width of the second notch, and the width of the third long stripe pattern is less than the width of the second long stripe pattern; in the second direction, the length of the second long strip pattern is greater than the interval between the adjacent second notches of the adjacent first long strip pattern, and the length of the third long strip pattern is less than the length of the second long strip pattern.
In addition, the bottom layer auxiliary grid is formed by adopting burn-through type slurry printing.
In addition, the main grid and the top-layer auxiliary grid are formed by adopting non-burning-through type slurry printing.
Correspondingly, the embodiment of the invention also provides a battery piece, which comprises: the battery piece substrate, a plurality of main bars and with a plurality of vice bars of main bar overlap joint, main bar with the vice bar all is located on the battery piece substrate, a plurality of main bars are parallel to each other, the extending direction perpendicular to of vice bar the extending direction of main bar, just the both sides of main bar with a plurality of the overlap joint of vice bar has first breach, the both ends of vice bar are embedded in two adjacent one of main bar respectively first breach.
In addition, the bottom layer auxiliary grid is made of fire-through type slurry, and the top layer auxiliary grid and the main grid are made of non-fire-through type slurry.
In addition, in the extending direction perpendicular to the bottom layer auxiliary grid, the width of the bottom layer auxiliary grid is greater than that of the first notch, and the width of the top layer auxiliary grid is smaller than that of the bottom layer auxiliary grid; in the extending direction of the bottom-layer auxiliary grid, the length of the bottom-layer auxiliary grid is greater than the interval between the adjacent first gaps of the adjacent main grids, and the length of the top-layer auxiliary grid is less than that of the bottom-layer auxiliary grid; in the direction perpendicular to the battery piece substrate, the height of the bottom layer auxiliary grid is greater than that of the main grid.
Compared with the prior art, the technical scheme provided by the embodiment of the invention has the following advantages:
the main grid and the auxiliary grid are printed on the battery piece substrate step by step, the height of the main grid can be reduced, the height of the auxiliary grid can be increased on the premise of not changing the width of the main grid and the auxiliary grid, the height-width ratio of the auxiliary grid can be improved, the transmission resistance of the auxiliary grid can be reduced, and the conversion efficiency of the battery piece can be improved. In addition, in the extending direction of the main gates, a plurality of first gaps which are arranged at intervals are arranged on two sides of each main gate, and two ends of each auxiliary gate are filled with one first gap of two adjacent main gates, so that on one hand, the contact area between the main gates and the auxiliary gates is increased, and the current transmission efficiency between the main gates and the auxiliary gates is improved; on the other hand, the end part of the auxiliary grid is positioned in the first notch of the main grid, and the auxiliary grid with partial height is overlapped with the main grid at the overlapping and overlapping position of the main grid and the auxiliary grid in the height direction of the main grid, so that the height difference between the auxiliary grid and the main grid is favorably reduced, and the welding yield between the battery piece and the battery piece is improved.
In addition, at present, due to the restriction of slurry rheological property, the height of the auxiliary grid is further increased, the width of the auxiliary grid is also increased, and the increase of the width of the auxiliary grid reduces the effective light receiving area of the cell. In the embodiment of the invention, the auxiliary grid comprises a bottom layer auxiliary grid and a top layer auxiliary grid, the bottom layer auxiliary grid and the top layer auxiliary grid are sequentially printed on the battery piece substrate, and the top layer auxiliary grid is positioned on one side of the bottom layer auxiliary grid, which is far away from the battery piece substrate. The secondary grid overlapping is beneficial to further improving the height of the secondary grid on the premise of not increasing the width of the secondary grid, so that the height-width ratio of the secondary grid is improved to reduce the transmission resistance of the secondary grid, and the conversion efficiency of the battery piece is improved.
Detailed Description
It is known from the background art that the prior art faces the problems of too large height difference between the main gate and the auxiliary gate and low current transmission efficiency while improving the aspect ratio of the auxiliary gate.
In order to improve the height-width ratio of the auxiliary grid, when the height of the main grid is lowered, the height of the auxiliary grid can be raised, but the excessive height difference between the main grid and the auxiliary grid can cause the insufficient soldering phenomenon between the battery pieces, thus the conductivity between the battery pieces is influenced, and the welding yield is low. In addition, the contact area between the main grid and the auxiliary grid is reduced due to the reduction of the height of the main grid, so that the current transmission efficiency between the main grid and the auxiliary grid is reduced, the current collection efficiency of the main grid to the auxiliary grid is further reduced, namely, the main grid with the reduced height is not beneficial to effectively collecting the current collected by the auxiliary grid with the increased height, and the conversion efficiency of the cell is low.
In order to solve the above problems, embodiments of the present invention provide a method for printing a battery piece in combination, where a main grid and an auxiliary grid are printed on a substrate of the battery piece step by step, in an extending direction of the main grid, two sides of each main grid are provided with a plurality of first gaps arranged at intervals, and two ends of each auxiliary grid are filled with one first gap of two adjacent main grids, so that on one hand, it is beneficial to increase a contact area between the main grid and the auxiliary grid to improve a current transmission efficiency between the main grid and the auxiliary grid, thereby improving a conversion efficiency of the battery piece; on the other hand, the height difference between the main grid and the auxiliary grid is favorably reduced, so that the welding yield between the battery pieces is improved.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that in various embodiments of the invention, numerous technical details are set forth in order to provide a better understanding of the present application. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments.
Fig. 1 is a schematic top view of a battery sheet after a main grid is formed on a battery sheet substrate in a battery sheet combination printing method according to a first embodiment of the present invention; FIG. 2 is a schematic top view of a first screen printed pattern used for printing a main grid according to the first embodiment of the present invention; fig. 3 is a schematic top view of a battery sheet after forming a primary grid and a secondary grid on a battery sheet substrate in a battery sheet combination printing method according to a first embodiment of the present invention; FIG. 4 is a schematic cross-sectional view taken along AA1 of FIG. 3; fig. 5 is another schematic top view of a battery sheet after forming a primary grid and a secondary grid on a battery sheet substrate in a battery sheet combination printing method according to a first embodiment of the invention; fig. 6 is a schematic cross-sectional view along the BB1 direction shown in fig. 5.
Referring to fig. 1, a battery sheet substrate 100 is provided, and a plurality of main grids 101 are formed on the battery sheet substrate 100 by printing, wherein the main grids 101 are parallel to each other, and in the extending direction of the main grids 101, both sides of each main grid 101 are provided with a plurality of first notches 111 arranged at intervals.
The first notch 111 facilitates a subsequently formed sub-gate to overlap the main gate 101 at this point.
Specifically, the step of printing and forming the plurality of main grids 101 on the battery sheet substrate 100 includes:
referring to fig. 2, the main grid 101 is formed using a first screen printing pattern including a plurality of first elongated patterns 121 extending in a first direction I of the battery sheet substrate 100, the elongated patterns 121 being parallel to each other, and both sides of the elongated patterns 121 having a plurality of second notches 131 spaced apart from each other, the second notches 131 being used to print the first notches 111 on the battery sheet substrate 100.
The first screen printing pattern enables two sides of the main grid 101 formed by printing to be provided with a plurality of first notches 111 arranged at intervals, so that the subsequently formed auxiliary grid can be embedded into the main grid 101 through the first notches 111, the contact area between the main grid 101 and the subsequently formed auxiliary grid is increased, and the current transmission efficiency between the main grid 101 and the subsequently formed auxiliary grid is improved.
Referring to fig. 3, a plurality of sub-grids 102 are printed on the battery sheet substrate 100, the extending direction of the sub-grids 102 is perpendicular to the extending direction of the main grids 101, the height of the sub-grids 102 is greater than that of the main grids 101 in the direction perpendicular to the battery sheet substrate 100, the sub-grids 102 are at least located between two adjacent main grids 101, and two ends of the sub-grids 102 respectively fill one first notch 111 of two adjacent main grids 101.
In this embodiment, referring to fig. 3 and 4 in combination, the two first notches 111 on both sides of one main grid 101 are filled with the end portions of two sub-grids 102, respectively, and since the height of the sub-grid 102 is greater than that of the main grid 101, a part of the sub-grid 102 overlaps the surface of the main grid 101. On one hand, the auxiliary grid 102 is positioned in the first notch 111, which is beneficial to increasing the contact area between the main grid 101 and the auxiliary grid 102, so that the current transmission efficiency between the main grid 101 and the auxiliary grid 102 is improved, and the conversion efficiency of the battery piece is improved; on the other hand, due to the existence of the first notch 111, in the process of forming the auxiliary grid 102, at the position where the main grid 101 and the auxiliary grid 102 coincide with each other, due to the existence of the first notch 111, the slurry flows into the first notch 111, fills the first notch 111 completely, and then flows into the surface of the main grid 101, compared with the case without the first notch 111, the slurry is directly accumulated on the surface of the main grid 101 at the coinciding position of the main grid 101 and the auxiliary grid 102 to form a higher auxiliary grid 102, and the two ends of the auxiliary grid 102 are respectively filled with one first notch 111 of two adjacent main grids 101, which is beneficial to reducing the height difference between the main grid 101 and the auxiliary grid 102, improving the welding yield between the battery piece and the battery piece, and thus improving the conductivity between the battery piece and the battery piece.
In addition, the sub-grids 102 are arranged intermittently along the second direction II (perpendicular to the first direction I) of the battery piece substrate 100, which is beneficial to reducing the consumption of the slurry for preparing the sub-grids 102, and thus reducing the cost for preparing the sub-grids 102.
In other embodiments, referring to fig. 5 and 6 in combination, the sub-grid 102 may also be a through type along the second direction II of the battery cell substrate 100, which may further increase the contact area between the main grid 101 and the sub-grid 102, and may also reduce the height difference between the main grid 101 and the sub-grid 102.
The second embodiment of the present invention further provides a battery sheet combination printing method, which is substantially the same as the previous embodiment, and the main differences include: the auxiliary grid comprises a bottom layer auxiliary grid and a top layer auxiliary grid which are sequentially printed. The method for printing a battery piece assembly according to the second embodiment of the present invention will be described in detail below with reference to the accompanying drawings, and the same or corresponding portions as those in the previous embodiment can be referred to the description of the previous embodiment, and will not be described in detail below.
Fig. 7 is a schematic top view of a battery sheet after a primary grid and a secondary grid are formed on a battery sheet substrate in a battery sheet combination printing method according to a second embodiment of the invention; FIG. 8 is a schematic top view of a second screen printed pattern used to print an underlying subgrid in accordance with a second embodiment of the invention; fig. 9 is a schematic top view of a third screen printed pattern for printing the top-layer sub-grid according to the second embodiment of the present invention. Referring to fig. 7, the sub-gate 202 includes a bottom sub-gate 212 and a top sub-gate 222; the step of printing a plurality of sub-grids 202 on the battery sheet substrate 200 includes:
with reference to fig. 8, the bottom sub-grid 212 is formed by using a second screen printing pattern, the second screen printing pattern includes a plurality of second long stripe patterns 232 extending along the second direction II of the battery sheet substrate 200, the second direction II is perpendicular to the first direction I, the plurality of second long stripe patterns 232 are arranged in a regular array, and an orthogonal projection of the second long stripe patterns 232 on the battery sheet substrate 200 covers an orthogonal projection of the second gaps 131 (refer to fig. 2) in the first long stripe patterns used for forming the main grid on the battery sheet substrate 200, that is, an orthogonal projection of the second long stripe patterns 232 on the battery sheet substrate 200 covers an orthogonal projection of the first gaps of the main grid on the battery sheet substrate 200.
With combined reference to fig. 9, a third screen printing pattern is used to form the top layer sub-grid 222 on the side of the bottom layer sub-grid 212 away from the battery sheet substrate 200, the third screen printing pattern includes a plurality of third strip patterns 242 extending along the second direction II, the plurality of third strip patterns 242 are arranged in a regular array, and an orthographic projection of the third strip patterns 242 on the battery sheet substrate 200 is located in an orthographic projection of the second strip patterns 232 on the battery sheet substrate 200.
In this embodiment, the sub-grid 202 is formed by overlapping, and the top-layer sub-grid 222 is formed on the basis of forming the bottom-layer sub-grid 212, which is beneficial to further improving the height of the sub-grid 202 on the basis of not increasing the width of the sub-grid 202, i.e. on the premise of not affecting the effective light receiving area of the battery piece, thereby improving the aspect ratio of the sub-grid 202 and the conversion efficiency of the battery, and when the printed and formed bottom-layer sub-grid 212 has a printing defect, such as a broken grid, during the subsequent formation of the top-layer sub-grid 222, the slurry can fill the broken grid of the bottom-layer sub-grid 212, which is beneficial to improving the problem of broken grid of the sub-grid 202.
In addition, the orthographic projection of the second elongated pattern 232 on the battery sheet substrate 200 covers the orthographic projection of the second notch 131 (refer to fig. 2) of the first elongated pattern used for forming the main grid on the battery sheet substrate 200, so that the two ends of the bottom layer auxiliary grid 212 formed by printing the second screen printing pattern can be ensured to be respectively filled in one first notch 211 of two adjacent main grids 201.
In addition, since the shape of the second long stripe patterns 232 is not greatly different from that of the third long stripe patterns 242, a screen having the same specification can be adopted, and different screen printing patterns can be designed on the screen without changing the specification of the screen, which is beneficial to reducing the cost of forming the sub-grid 202 by printing.
In the present embodiment, the width of the second stripe pattern 232 is greater than the width of the second notch 131 of the first stripe pattern used for forming the main gate in the first direction I.
Since the second long stripe pattern 232 corresponds to the subsequently formed bottom layer sub-gate 222 and the second notch 131 of the first long stripe pattern for forming the main gate corresponds to the first notch 211 at two sides of the subsequently formed main gate 201, the width of the second long stripe pattern 232 is greater than the width of the second notch 131 of the first long stripe pattern for forming the main gate, that is, the width of the bottom layer sub-gate 212 is greater than the width of the first notch 211, which is beneficial for completely filling the first notch 211 with the slurry in the process of forming the bottom layer sub-gate 212, thereby being beneficial for improving the contact area between the bottom layer sub-gate 212 and the first notch 211 and improving the current transmission efficiency between the bottom layer sub-gate 212 and the main gate 201.
In addition, in the second direction II, the length of the second long bar pattern 232 is greater than the interval between adjacent second gaps 131 (refer to fig. 2) of adjacent first long bar patterns 121 (refer to fig. 2) for forming the main gate.
Because the first strip patterns 121 correspond to the formed main gates 201, when the length of the second strip patterns 232 is greater than the interval between the adjacent second gaps 131 of the adjacent first strip patterns 121 for forming the main gates, it is beneficial to ensure that the paste not only flows into the first gaps 211 but also covers the surface of the main gates 201 under the influence of printing alignment errors and paste fluidity, thereby ensuring the stability of the lap joint between the main gates 201 and the bottom layer sub-gates 212 and further improving the current transmission efficiency between the bottom layer sub-gates 212 and the main gates 201.
Further, in the first direction I, the width of the third long bar patterns 242 is smaller than the width of the second long bar patterns 232; in the second direction II, the length of the third bar patterns 242 is less than the length of the second bar patterns 232.
Because the third strip patterns 242 correspond to the top-layer sub-gates 222 to be formed subsequently, when the width of the third strip patterns 242 is smaller than the width of the second strip patterns 232 and the length of the third strip patterns 242 is smaller than the length of the second strip patterns 232, the width of the top-layer sub-gates 222 is also smaller than the width of the bottom-layer sub-gates 212, and the length of the top-layer sub-gates 222 is also smaller than the length of the bottom-layer sub-gates 212, therefore, on the premise that the overall sub-gates 202 have a high aspect ratio, the consumption of the paste for preparing the sub-gates 202 is reduced, and the cost for preparing the sub-gates 202 is reduced.
In this embodiment, the bottom-layer sub-grid 212 may be formed by printing through-fire type paste, which can ensure that the bottom-layer sub-grid 212 is through-fired through the passivation layer of the cell substrate 200, so that the bottom-layer sub-grid 212 forms ohmic contact with the silicon substrate under the passivation layer to collect current.
In addition, the present embodiment may use non-fire through type paste printing to form the main gate 201 and the top sub-gate 222. Because the main gate 201 and the bottom layer auxiliary gate 212 are in contact with each other at the first notch 211 to realize ohmic contact, ohmic contact between the main gate 201 and the silicon substrate is not required, and therefore, non-fire-through type slurry with lower cost can be selected, and the cost of the slurry is favorably controlled. The top layer sub-gate 222 is in direct contact with the bottom layer sub-gate 212 to achieve ohmic contact, and a lower cost non-fire through type paste may be selected to control the cost of the paste.
In this embodiment, the bottom-layer sub-grid 212 and the top-layer sub-grid 222 are both discontinuously arranged along the second direction II of the battery cell substrate 200, which is beneficial to reducing the consumption of the slurry for preparing the sub-grid 202, thereby reducing the cost for preparing the sub-grid 202.
In other embodiments, the bottom layer secondary grid and the top layer secondary grid can also be of a penetrating type along the second direction II of the cell substrate, so that the contact area between the main grid and the bottom layer secondary grid can be further increased, and the height difference between the main grid and the secondary grid can also be reduced.
In this embodiment, the contact area between the main grid 201 and the bottom-layer auxiliary grid 212 can be increased by the auxiliary grid 202 in a superposition manner, so that the current transmission efficiency between the main grid 201 and the bottom-layer auxiliary grid 212 is improved, the conversion efficiency of the battery piece is improved, the height difference between the main grid 201 and the bottom-layer auxiliary grid 212 is reduced, the welding yield between the battery piece and the battery piece is improved, and the height of the auxiliary grid 202 is further improved and the problem of grid breakage of the auxiliary grid 202 is solved on the premise that the effective light receiving area of the battery piece is not changed.
Correspondingly, the embodiment of the invention also provides a battery piece, which comprises: the battery piece substrate, a plurality of main bars and a plurality of auxiliary bars lapped with the main bars, wherein the main bars and the auxiliary bars are both positioned on the battery piece substrate, the main bars are parallel to each other, the extending direction of the auxiliary bars is perpendicular to the extending direction of the main bars, first notches are arranged at the lapping positions of the two sides of each main bar and the auxiliary bars, and the two ends of each auxiliary bar are embedded in the first notches of the two adjacent main bars respectively.
The main grids are provided with the first notches, and the two ends of the auxiliary grids are respectively embedded into one first notch of each two adjacent main grids, so that on one hand, the contact area between the main grids and the auxiliary grids is increased, the current transmission efficiency between the main grids and the auxiliary grids is improved, and the conversion efficiency of the battery piece is improved; on the other hand, the height difference between the main grid 101 and the auxiliary grid is reduced, the welding yield between the battery pieces is improved, and therefore the conductivity between the battery pieces is improved.
Referring to fig. 7 and 10 together, fig. 10 is a schematic cross-sectional view taken along CC1 shown in fig. 7. The secondary grid 202 includes a bottom layer secondary grid 212 and a top layer secondary grid 222 that are sequentially stacked in a direction perpendicular to the cell substrate 200.
Preferably, the bottom-layer auxiliary grid 212 is made of fire-through type slurry, and the top-layer auxiliary grid 222 and the main grid 201 are made of non-fire-through type slurry, which is beneficial to reducing the cost for preparing the main grid 201 and the auxiliary grid 202.
In addition, in another preferred embodiment, in the direction perpendicular to the extension direction of the bottom-layer sub-gate 212, the width of the bottom-layer sub-gate 212 is greater than the width of the first notch 211, and the width of the top-layer sub-gate 222 is smaller than the width of the bottom-layer sub-gate 212; in the extending direction of the bottom-layer secondary grid 212, the length of the bottom-layer secondary grid 212 is greater than the interval between the adjacent first notches 211 of the adjacent main grids 201, and the length of the top-layer secondary grid 222 is less than that of the bottom-layer secondary grid 212; the height of the bottom layer secondary grid 212 is greater than the height of the primary grid 201 in a direction perpendicular to the cell substrate 200.
The width of the bottom-layer auxiliary grid 212 is greater than the width of the first notch 211, the length of the bottom-layer auxiliary grid 212 is greater than the interval between the adjacent first notches 211 of the adjacent main grids 201, and the height of the bottom-layer auxiliary grid 212 is greater than the height of the main grid 201, so that the bottom-layer auxiliary grid 212 can be further ensured to fill the first notch 211 of the main grid 201, the bottom-layer auxiliary grid 212 is also positioned on the surface of the main grid 201, and a sufficiently large contact area between the main grid 201 and the bottom-layer auxiliary grid 212 is ensured, thereby ensuring a good current transmission effect between the main grid 201 and the bottom-layer auxiliary grid 212.
The width of the top-layer sub-grid 222 is smaller than the width of the bottom-layer sub-grid 212, and the length of the top-layer sub-grid 222 is smaller than the length of the bottom-layer sub-grid 212, which is beneficial to reducing the consumption of slurry for preparing the sub-grid 202 on the premise of ensuring that the whole sub-grid 202 has a high aspect ratio, thereby reducing the cost for preparing the sub-grid 202.
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.