CN215220741U - Back electric field structure for improving efficiency of laminated assembly battery and battery - Google Patents

Abstract

The utility model discloses a promote back electric field structure and battery of shingle assembly battery efficiency belongs to brilliant silicon solar cell field. In the back electric field structure of the utility model, the main grid is provided with a plurality of inflection points along the length direction, and the protruding directions of any adjacent inflection points are opposite; the utility model provides a stack tile subassembly battery, its openly sets up the cutting passageway for guide cutting owner bars, make along the main bars after the cutting passageway cutting, the minimum distance that is located the silver electrode at the A flex point and is cut the limit apart from the main bars left side limit is less than the minimum distance that is located the silver electrode at the B flex point and is cut the limit apart from the main bars left side limit. The utility model discloses a transmission path of electric current is improved to the structure of optimal design shingling subassembly battery back electrode, reduces near the different regional current density difference of back main grid, reduces contact resistance, reduces the current loss to improve battery fill factor.

Description

Back electric field structure for improving efficiency of laminated assembly battery and battery

Technical Field

The utility model belongs to brilliant silicon solar cell field, more specifically say, relate to a promote back electric field structure and battery of shingle assembly battery efficiency.

Background

The shingle assembly can shorten the electronic movement distance, reduce the resistance and improve the power because of abandoning the welding strip interval connection conduction mode, thereby becoming a hotspot of the research and development of high-efficiency assembly technology. The laminated assembly is formed by directly connecting the positive electrode and the back electrode of the sliced battery with a conductive adhesive in a gapless manner, so that more battery pieces can be packaged under the condition of the same assembly area, and the power generation density of the assembly is improved. However, the bonding strength of the conductive adhesive is smaller than the welding strength of the welding strip, so the back electrode is usually designed into a multi-section staggered hollow structure to increase the bonding force of the positive electrode and the negative electrode and reduce the contact resistance.

At present, the back surface of a laminated assembly battery is composed of aluminum fine grids and main grids which are uniformly and parallelly distributed, and an auxiliary grid is vertically connected with the main grids. The auxiliary grid is formed by aluminum paste, and collected carriers are transmitted and gathered on the main grid in a current mode; the main grid is generally composed of a silver electrode and an aluminum electric field, and the current is finally led out by the silver electrode. The back electrode pattern of the conventional shingled assembly cell is generally designed as a straight-through type (see fig. 1) with a multi-segmented staggered arrangement, and when carriers are transferred from the fine grid 200 to the silver electrode 300, as shown in fig. 2, the distance difference between the left and right sides of the same region is large, resulting in a narrow region (L)₁) Has an excessively high carrier density and a wide region (L)₂) Too low a carrier density. The carrier density difference between the narrow region and the wide region can ensure that the carriers near the narrow region are not directly gathered to the silver electrode for exporting, but additionally increases a path which bypasses from the vicinity of the narrow region to the vicinity of the wide region and then reaches the silver electrode 300. And because the resistivity of aluminum is far greaterIn the resistivity of silver, the contact resistance caused by the transmission path along which carriers are transported is significantly increased, which causes current loss, thereby reducing the filling performance of the battery, resulting in efficiency reduction, and being not favorable for the development of high-power target of the laminated assembly.

In the current through type back electrode structure design of the laminated assembly battery, an optimized space exists in a current transmission path, contact resistance and a filling factor, and if a technical route of the laminated assembly battery is improved by adding grid lines, the problems of certain difficulty and assembly reliability need to be considered are solved. With the increase of the size of the silicon wafer, the problems of poor carrier collection effect, overhigh resistivity, component cutting and the like caused by the current design are further highlighted.

Aiming at the problems, how to improve the transmission path of current by optimizing the back electrode structure of the laminated assembly battery is to integrally reduce the resistivity and improve the filling factor of the battery, which is a difficult problem to be solved by the laminated assembly battery technology.

Disclosure of Invention

1. Problems to be solved

The problem to prior art exists, the utility model provides a promote back electric field structure of shingle assembly battery efficiency, main bars set up a plurality of flex points along length direction, and the protruding opposite direction of arbitrary adjacent flex point, and the structure through the electrode at the back of optimal design shingle assembly battery improves the transmission path of electric current, reduces near the different regional current density difference of main bars in the back, reduces contact resistance, reduces the current loss to improve battery fill factor.

Further, the utility model provides a stack tile subassembly battery, its openly sets up the cutting passageway for guide cutting owner bars, make along the main bars after the cutting passageway cutting, the minimum distance that is located the silver electrode at the A flex point and is cut the limit apart from the main bars left side is less than the minimum distance that is located the silver electrode at the B flex point and is cut the limit apart from the main bars left side, can realize best current transmission effect.

2. Technical scheme

In order to solve the above problem, the utility model discloses the technical scheme who adopts as follows:

the utility model provides a back electric field structure for improving the battery efficiency of a laminated tile assembly, which comprises at least two main grids, wherein the left side edge and the right side edge of each main grid are provided with a plurality of thin grids, any two thin grids are arranged in parallel, and any two adjacent main grids are communicated through the plurality of thin grids; a plurality of silver electrodes are arranged on the main grid along the length direction, and one side edge of the main grid is at least provided with an A inflection point protruding towards the A direction.

Preferably, any one side of the main grid has an a inflection point protruding towards the a direction and a B inflection point protruding towards the B direction, the a inflection point and the B inflection point are arranged in a staggered manner along the length direction of the channel, and the a direction is opposite to the B direction. Further, the side of the present invention is not necessarily a smooth curve, but also a similar smooth curve composed of a plurality of line segments. Preferably, the normals of the inflection points a of the two side edges are coincident, so that the whole back electrode is in an S shape to maintain the total area of the aluminum back field to be basically unchanged. Furthermore, the side of the main grid can be in a lug shape or a triangular shape, and two inflection points in opposite directions can be formed.

The design of the aluminum back field with the inflection point is adopted, the existing transverse and longitudinal current transmission mode is changed, the current collection path is effectively reduced, the current collection effect is improved, and the current loss caused by overlarge aluminum resistance is reduced. Under the same aluminum auxiliary grid design condition, the battery filling factor can be improved by 0.3%, and meanwhile, the photoelectric conversion efficiency of the PERC double-sided battery can be improved by more than 0.1%. Meanwhile, the S-shaped design of the main grid reduces the collection blank area, so that the carrier is more uniformly distributed in the transmission process

Preferably, any one of the main gates has the same width L, and the width L is 1-4 mm. More preferably 2.5 to 2.9 mm.

Preferably, the side of the main gate has a curvature K of not less than 0.5mm, the curvature K being a distance between a tangent line of any adjacent a inflection point and a tangent line of B inflection point on the same side.

Preferably, the main grid is provided with a left side and a right side, the silver electrode is arranged at the A inflection point and the B inflection point, and the distance between the silver electrode I positioned at the A inflection point and the right side is L₁Silver electrode at B inflection pointThe distance between the pole II and the right side edge is L₂，L₁And L₂Not equal.

Preferably, the distance between any two adjacent fine grids is 0.8-1.5 mm.

Preferably, the distance between the normal line of the inflection point A and the normal line of the inflection point B is J, and the distance J is in inverse proportion to the curvature K, namely, when the distance between the silver electrodes is increased, the curvature is correspondingly reduced, the aluminum consumption is reduced, and the processing cost is reduced.

Preferably, L₁0.2-0.8mm, and/or L₂0.4-1.2 mm. Further preferably, L₁0.55mm, and/or L₂＝0.65mm。

Preferably, silver electrode I all is located axle I, and silver electrode II all is located axle II, and axle I and axle II parallel arrangement.

The utility model further provides a laminated assembly battery, which is provided with a back electric field structure and a front electric field structure relative to the back electric field structure, wherein the back electric field structure adopts the back electric field structure for improving the efficiency of the laminated assembly battery; the front electric field structure is provided with a cutting channel which is arranged corresponding to the back electric field structure; the cutting channel is used for guiding and cutting the main grid, so that the minimum distance between the cut edge of the silver electrode at the A inflection point and the left side edge of the main grid on the main grid cut along the cutting channel is L₃The minimum distance between the cut edge of the silver electrode at the B inflection point and the left side edge of the main grid is L₄，L₃＞L₄。

Preferably, any side edge of the cutting channel is provided with a C inflection point protruding towards the C direction and a D inflection point protruding towards the D direction, the C inflection point and the D inflection point are arranged in a staggered mode along the length direction of the channel, and the C direction is opposite to the D direction.

Preferably, the width of the cutting channel is smaller than the width of the main grating, i.e. the main grating can accommodate the cutting channel when viewed from an angle perpendicular to the plane of the cutting channel.

Preferably, the inflection point C is arranged corresponding to the inflection point A, and the direction C is opposite to the direction A; the D inflection point and the B inflection point are correspondingly arranged, the D direction is opposite to the B direction, and the S-shaped cutting channel can achieve a better cutting effect.

Preferably, the curvature of the side of the cutting channel is smaller than the curvature of the side of the main grid.

Preferably, the normal of the C inflection point coincides with the normal of the a inflection point, and further, the normal of the D inflection point coincides with the normal of the B inflection point, so that the optimal cutting effect can be achieved.

3. Advantageous effects

Compared with the prior art, the utility model discloses the main grid sets up a plurality of flex points along length direction, and the protruding opposite direction of arbitrary adjacent flex point, can realize promoting by a wide margin of back electrode pair current carrier collection effect under the condition that does not have negative effects to performance such as back shading area, thick liquid consumption and assembly welding, realizes the promotion more than 0.1% of PERC battery piece photoelectric conversion efficiency. Moreover, the utility model discloses reduce the isolation between aluminium back of the body field and the silver-colored electrode by a wide margin and collect blank area, promote the improvement that back electrode pair current carrier was collected to the effect conversion efficiency of battery piece has been promoted, the design to the jumbo size battery is promoted and is provided bigger optimization space.

Drawings

FIG. 1 is a partially enlarged view of a back electrode of a conventional stack-tile assembly cell;

FIG. 2 is a schematic view of carrier transport in the back electrode region of a conventional stacked cell;

fig. 3 is a partial schematic view of a back structure of a battery in embodiment 1, wherein: 1-back surface electric field; 2-a back electrode;

FIG. 4 is a partial enlarged view (one) of the back electrode of the shingled cell in example 1;

FIG. 5 is a partial enlarged view of the back electrode of the shingled cell of example 1 (II);

FIG. 6 is an enlarged view of a portion of the back electrode of a shingled battery after cutting with a straight line;

fig. 7 is a partial enlarged view (iii) of the back electrode of the shingled cell in example 1.

In the figure:

100. a main grid; 200. fine grids; 300. and a silver electrode.

Detailed Description

The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration exemplary embodiments in which the invention may be practiced, and in which elements and features of the invention are identified by reference numerals. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to provide the best mode contemplated for carrying out the invention and to enable any person skilled in the art to practice the invention. It will, however, be understood that various modifications and changes may be made without departing from the scope of the invention as defined by the appended claims. The detailed description and drawings are to be regarded as illustrative rather than restrictive, and any such modifications and variations are intended to be included within the scope of the present invention as described herein. Furthermore, the background is intended to illustrate the present state of the art and the meaning of the present development and is not intended to limit the present invention or the present application and the field of application of the present invention.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present; as used herein, the terms "vertical," "horizontal," "left," "right," "inner," "outer," "a-direction," "B-direction," "C-direction," "D-direction," and the like are for purposes of description only.

Example 1

In this embodiment, as a specific implementation manner, the aluminum electrode mesh plate design is adopted to implement the preparation of the stacked assembly battery of this embodiment.

In this embodiment, as a specific implementation manner, the back electrode pattern is designed by using silver electrodes 300 distributed in a multi-segment staggered manner, and the aluminum back field is designed by using an S-shaped pattern (as shown in fig. 3), and the specific structure is as follows:

adopts a multi-main grid 100 structure with more than or equal to 6 strips, and a single main grid of the back electrodeThe silver electrode 300 on 100 adopts multiple segments, the number of the segments is 50, the width of the single silver electrode 300 is 1.2mm, the length is 2.0mm, and the silver electrodes are distributed in a left-right staggered manner. In this embodiment, the silver electrode 300 at the inflection point a is located on the axis i, the silver electrode 300 at the inflection point B is located on the axis ii, the axis i and the axis ii are arranged in parallel, and the distance between the axis i and the axis ii is smaller than the width of the silver electrode 300. Silver electrode 300 is sized and distributed in a manner that preserves the conventional shingle assembly cell back electrode design. Any side edge of the main grid 100 is provided with an A inflection point protruding towards the A direction and a B inflection point protruding towards the B direction, the A inflection point and the B inflection point are arranged in a staggered mode along the length direction of the channel, and the A direction is opposite to the B direction. In this embodiment, the side of the similar smooth curve composed of a plurality of line segments, that is, the inflection point may have a chamfer, so that the isolated collection blank area between the silver electrodes 300 on the side of the main gate 100 is more uniform, and the carrier distribution near the silver electrodes 300 is more uniform during the carrier transmission process. A smooth curve may also be used such that the entire back electrode is S-shaped to maintain the total aluminum back field area substantially constant. By uniformizing the distance from the aluminum fine grid 200 to the silver electrode 300, the collection capability of the back carrier is improved, so that the resistivity is reduced, and the photoelectric conversion efficiency is improved. Meanwhile, the distance between the normal line of the inflection point A and the normal line of the inflection point B is J, and the distance J is inversely proportional to the curvature K. Among them, as shown in fig. 4 and 5, it is preferable that the width L of the main grid 100 is 2.81mm, and the side of the main grid 100 has a curvature K of not less than 0.5 mm. The distance L between the silver electrode 300 at the inflection point A and the right side₁0.65mm, the distance L between the silver electrode 300 at the B-inflection point and the right side edge₂＝0.55mm。

The aluminum gate line also includes a second main gate and a fine gate 200 (fig. 3). Wherein, the fine grids 200 are distributed transversely and uniformly; the second main grids are distributed at equal intervals in the longitudinal direction, and the width of the aluminum main grid 100 is in a gradual change mode. The fine grid 200 is connected with the silicon substrate through laser grooving, so that the current in the substrate area is transversely collected, and then a part of the current is transmitted to the second main grid and is led out through the second main grid; a portion of the silver electrode 300 is transferred to the front electrode and then conducted to the front electrode.

The width of the fine gate 200 is 60-200 μm; the grid line spacing is 0.8-1.5 mm; the second main grid adopts gradual change, and the gradual change specification is 0.06-1.0 mm; preferably, the grade of the bamboo joint gradual change specification is 0.4mm/0.35mm/0.13 mm.

As a specific implementation manner, this embodiment further provides a back electrode preparation method, including:

s100, laser grooving and patterning: and adopting a divergent laser grooving pattern corresponding to the aluminum electrode to perform laser grooving at a position corresponding to the aluminum auxiliary grid region of the back electrode. The silver electrode 300 area is not laser grooved, and the specification of the non-grooved area is determined according to the design specification of the silver electrode 300. The utility model discloses under the preferred scheme, this non-fluting district preferred S type, width 2.81mm runs through whole battery piece.

S200, silver electrode 300 and pattern: and preparing silver electrodes 300 in staggered arrangement at corresponding positions on the back of the silicon wafer by adopting a screen printing mode.

S300, back electric field and preparation: adopt the utility model discloses back aluminium electric field pattern through screen printing mode preparation aluminium electric field, wherein adopts the high accuracy camera to snapshot laser MARK point mode and counterpoint, ensures the precision, preferentially chooses mesh number 360, 16 mu m of line footpath, sand thick 25 mu m, the thick 16 mu m's of membrane otter board for use.

As a specific implementation manner, this embodiment further provides a method for manufacturing a stack assembly cell, taking a single-crystal P-type silicon wafer as an example, which includes:

1. texturing: adopting a single crystal P-type silicon wafer, and using alkali to carry out front and back texturing to form a textured structure;

2. diffusion: reacting the silicon wafer after texturing with phosphorus oxychloride at high temperature to diffuse the front side to form a PN emitter junction; the sheet resistance of the front surface thin layer after diffusion is between 120 and 200 Ω/□, in this embodiment, the sheet resistance is 160 Ω/□;

3. laser SE: performing laser doping on the front surface of the diffused silicon wafer and the metalized area corresponding to the positive electrode grid line by using the diffused phosphorosilicate glass as a phosphorus source to form a heavily doped area, so that a structure of selecting an emitter is realized on the front surface of the silicon wafer, wherein the square resistance of the heavily doped area is between 80 and 90 omega/□, and in the embodiment, the square resistance is 85 omega/□;

4. thermal oxidation: introducing oxygen into the silicon wafer after the laser SE for oxidation;

5. removing PSG: removing the back surface and the peripheral PSG of the silicon wafer after thermal oxidation by using HF;

6. alkali polishing: polishing the back and the edge of the silicon wafer after the PSG is removed, and removing the PSG on the front;

7. oxidizing and annealing: carrying out oxidation and annealing treatment on the silicon wafer subjected to alkali polishing;

8. depositing a passivation film on the back: preparing a passivation film on the back of the annealed silicon wafer;

9. front side deposition of an antireflection film: preparing a passivation and antireflection layer on the front side of the silicon wafer;

10. back laser: according to the scheme, laser tapping is performed on the passivation film on the back of the silicon wafer;

11. preparing a back electrode: preparing a back silver electrode by adopting 6 main grids and 50 segmented electrode patterns (as shown in figure 3), selecting silver paste and adopting a screen printing mode; wherein, the width of the back silver is 1.6mm, and the length of the back silver is 2.1 mm; selecting aluminum paste for preparing the thin grid 200 on the silicon wafer with the back silver electrode; adopting a screen plate with 360 meshes, 16 mu m of wire diameter, 25 mu m of sand thickness and 16 mu m of film thickness to simultaneously print by a screen printing mode;

12. printing the positive electrode main grid 100 region: adopting front silver paste to prepare a front electrode on a silicon chip printed with a back electrode by screen printing;

13. and (3) sintering: co-sintering the silicon chip with the front electrode printed, wherein the sintering peak temperature is 720-;

14. electric injection: carrying out electric injection treatment on the sintered battery piece;

15. and (3) finished product: and testing, sorting, packaging and warehousing the product battery pieces.

Example 2

The basic contents of this embodiment are different from those of embodiment 1 in that: in this embodiment, based on the back electric field structure of embodiment 1, this embodiment further provides a cell with a stack module, which has a back electric field structure and a front electric field structure opposite to the back electric field structure, where the back electric field structure is the back electric field structure in embodiment 1 for improving the efficiency of the cell with the stack module; front surface electric field junctionA cutting channel is formed, and the cutting channel is arranged corresponding to the back surface electric field structure; as shown in fig. 6, the cutting path is used to guide the cutting of the main grid 100 such that the minimum distance L from the cut edge of the silver electrode 300 located at the a-inflection point to the left side of the main grid 100 is set at the cut edge of the main grid 100 after the cutting along the cutting path₃The minimum distance between the cut edge of the silver electrode 300 at the B inflection point and the left side of the main grid 100 is L₄，L₃＞L₄。

Example 3

The basic contents of this embodiment are different from those of embodiment 2 in that: any side edge of the cutting channel is provided with a C inflection point protruding towards the C direction and a D inflection point protruding towards the D direction, the C inflection point and the D inflection point are arranged in a staggered mode along the length direction of the channel, and the C direction is opposite to the D direction. The width of the cutting channel is smaller than that of the main grid 100, and the curvature of the side edge of the cutting channel is smaller than that of the side edge of the main grid 100, so that a better cutting effect is realized.

Furthermore, the inflection point C is arranged corresponding to the inflection point A, and the direction C is opposite to the direction A; the D inflection point and the B inflection point are correspondingly arranged, and the direction of the D inflection point is opposite to the direction of the B inflection point, so that after cutting, the distance from the cut edge of the silver electrode 300 at the B inflection point to the left side edge of the main grid 100 is L₄A minimum value may be reached. The normal of the C inflection point is coincident with the normal of the A inflection point, and the normal of the D inflection point is coincident with the normal of the B inflection point.

Example 4

The basic content of this embodiment is the same as that of embodiment 1, except that in this embodiment, one side of the main gate 100 is provided with an inflection point a, the other side is provided with an inflection point B, and the normals of the inflection point a and the inflection point B are not overlapped, so that two sides of the main gate 100 are arc-shaped with only one convex point. However, when the main gate 100 of the present embodiment is manufactured, the printed area is too large, and the processing cost is higher than that of embodiment 1.

Example 5

The basic content of this embodiment is the same as that of embodiment 1, except that, as shown in fig. 7, the side of the main grid 100 of this embodiment has only an a-inflection point of the a-direction protrusion, forming an ear-wrapping type side, and the side is formed by interleaving an arc protrusion and a straight line segment.

Example 6

The basic content of this embodiment is the same as that of embodiment 1, except that in this embodiment, the side of the main gate 100 is composed of a plurality of adjacent triangle sides, and the triangle side having the a-inflection point protruding in the a direction and the triangle side having the B-inflection point protruding in the B direction are staggered.

More specifically, although exemplary embodiments of the invention have been described herein, the invention is not limited to these embodiments, but includes any and all embodiments modified, omitted, such as combinations between various embodiments, adapted changes and/or substitutions as would be recognized by those skilled in the art from the foregoing detailed description. The limitations in the claims are to be interpreted broadly based the language employed in the claims and not limited to examples described in the foregoing detailed description or during the prosecution of the application, which examples are to be construed as non-exclusive. Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. The scope of the invention should, therefore, be determined only by the appended claims and their legal equivalents, rather than by the descriptions and examples given above.

Claims (17)

1. The utility model provides a promote back electric field structure of shingle assembly battery efficiency which characterized in that: comprises that

The left side and the right side of each main grid are provided with a plurality of fine grids, any two fine grids are arranged in parallel, and any two adjacent main grids are communicated through the plurality of fine grids;

a plurality of silver electrodes are arranged on the main grid along the length direction; one side edge of the main grid is at least provided with an A inflection point protruding towards the A direction.

2. The back surface electric field structure for improving the efficiency of a stack cell of claim 1, wherein: any side edge of the main grid is provided with an A inflection point protruding towards the A direction and a B inflection point protruding towards the B direction, the A inflection point and the B inflection point are arranged in a staggered mode along the length direction of the channel, and the A direction is opposite to the B direction.

3. The back surface electric field structure for improving the efficiency of a stack cell of claim 2, wherein: any position of the main grid has the same width L, and the width L is 1-4 mm.

4. The back surface electric field structure for improving the efficiency of a stack cell of claim 2, wherein: the side edge of the main grid is provided with a curvature K which is not less than 0.5mm, and the curvature K is the distance between any adjacent tangent line of the A inflection point and any adjacent tangent line of the B inflection point on the same side edge.

5. The back surface electric field structure for improving the efficiency of a stack cell of claim 2, wherein: the main grid is provided with a left side edge and a right side edge, the silver electrode is arranged at the A inflection point and the B inflection point, and the distance between the silver electrode I positioned at the A inflection point and the right side edge is L₁The distance between the silver electrode II at the inflection point B and the right side edge is L₂，L₁And L₂Not equal.

6. The back surface electric field structure for improving the efficiency of a stack cell of claim 2, wherein: the distance between any two adjacent fine grids is 0.8-1.5 mm.

7. The back surface electric field structure for improving the efficiency of a stack cell of claim 3, wherein: the width L is 2.5-2.9 mm.

8. The back surface electric field structure for improving the efficiency of a stack cell of claim 4, wherein: the distance between the normal line of the A inflection point and the normal line of the B inflection point is J, and the distance J is inversely proportional to the curvature K.

9. According to claim 5The back electric field structure for improving the efficiency of the laminated assembly battery is characterized in that: said L₁0.2-0.8mm, and/or said L₂＝0.4-1.2mm。

10. The back surface electric field structure for improving the efficiency of a stack cell of claim 5, wherein: silver-colored electrode I all is located axle I, silver-colored electrode II all is located axle II, axle I and II parallel arrangement of axle.

11. The back surface electric field structure for improving the efficiency of a stack cell of claim 9, wherein: said L₁0.55mm, and/or said L₂＝0.65mm。

12. A stack of tile assembly cells having a back electric field structure and a front electric field structure opposite the back electric field structure, comprising: the back surface electric field structure is used for improving the efficiency of the laminated assembly battery, and the back surface electric field structure is as claimed in any one of claims 1-11; the front electric field structure is provided with a cutting channel, and the cutting channel is arranged corresponding to the back electric field structure;

the cutting channel is used for guiding and cutting the main grid, so that the minimum distance between the cut edge of the silver electrode at the A inflection point and the left side edge of the main grid on the main grid cut along the cutting channel is L₃The minimum distance between the cut edge of the silver electrode at the B inflection point and the left side edge of the main grid is L₄，L₃＞L₄。

13. A stack-stack battery according to claim 12, wherein: any side edge of the cutting channel is provided with a C inflection point protruding towards the C direction and a D inflection point protruding towards the D direction, the C inflection point and the D inflection point are arranged in a staggered mode along the length direction of the channel, and the C direction is opposite to the D direction.

14. A stack-stack battery according to claim 12, wherein: the width of the cutting channel is smaller than that of the main grid.

15. A stack-stack battery according to claim 13, wherein: the inflection point C is arranged corresponding to the inflection point A, and the direction C is opposite to the direction A;

the D inflection point and the B inflection point are correspondingly arranged, and the direction of the D inflection point is opposite to the direction of the B inflection point.

16. A stack-stack battery according to claim 13, wherein: the curvature of the side of the cutting channel is smaller than that of the main grid side.

17. A stack-stack battery according to claim 15, wherein: the normal of the C inflection point is coincident with the normal of the A inflection point, and/or

And the normal line of the D inflection point is coincident with the normal line of the B inflection point.

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