Method for measuring contact resistivity of heterojunction cell

Abstract

The invention provides a method for measuring the contact resistivity of a heterojunction cell, the heterojunction cell comprises a doped silicon layer, a transparent conductive layer located on the doped silicon layer, and a plurality of grid lines arranged on the transparent conductive layer at intervals, and the method comprises the following steps: scribing a cell to obtain a unit cell to be measured; measuring a first contact resistance (RA) between the gate line and the transparent conductive layer; removing the transparent conductive layer between the adjacent grid lines, and reserving the transparent conductive layer below the grid lines; measuring a total second contact resistance (RB) between the grid line and the transparent conductive layer and between the transparent conductive layer and the doped silicon layer; calculating a contact resistance (RC) between the transparent conductive layer and the doped silicon layer from the first contact resistance (RA) and the second contact resistance (RB); and calculating the contact resistivity (rho) between the transparent conductive layer and the doped silicon layer according to the contact resistance (RC), the effective transmission distance (LT), the width (W) of the unit cell to be measured and the width (d) of the grid line. According to the measuring method, special sample preparation is not needed in the process of measuring the contact resistivity, battery pieces in mass production are directly used, and therefore the measuring method has the advantage of being simple in testing process.

Description

Technical Field

[0001] The present application mainly relates to the field of photovoltaic technology, and in particular to a method for measuring the contact resistivity of a heterojunction battery. Background Art

[0002] Heterojunction cells (HJT) are facing the challenge of further improving efficiency. The main electrical parameter that restricts the further improvement of the conversion efficiency of heterojunction cells is the fill factor (FF), which is affected by the various resistance losses inside the cell, such as the line resistance of the gate line, the contact resistance between the gate line and the transparent conductive layer (TCO), the thin film resistance of the transparent conductive layer, the contact resistivity between the transparent conductive layer and doped amorphous silicon, and the resistance of doped amorphous silicon. Therefore, how to correctly decompose and evaluate the resistance of each part of the heterojunction cell is of great guiding significance for optimizing the efficiency of the heterojunction cell, especially the contact resistivity between the transparent conductive layer and the doped amorphous silicon, which is of great guiding significance for the selection of the work function matching of the transparent conductive layer material and the deposition process conditions, the conductivity of the doped amorphous silicon, and the film formation conditions. Therefore, how to simply measure the contact resistivity between the transparent conductive layer and the doped amorphous silicon / microcrystalline silicon is a hot topic in this field. Summary of the invention

[0003] The technical problem to be solved by the present application is to provide a method for measuring the contact resistivity of a heterojunction battery, which does not require special sample preparation and can simply measure the contact resistivity between a transparent conductive layer and a doped silicon layer.

[0004] In order to solve the above technical problems, the present application provides a method for measuring the contact resistivity of a heterojunction battery, wherein the heterojunction battery comprises a doped silicon layer, a transparent conductive layer located on the doped silicon layer, and a plurality of grid lines arranged at intervals on the transparent conductive layer, comprising: scribing a battery cell to obtain a unit battery cell to be tested; measuring a first contact resistance (R A ); removing the transparent conductive layer between adjacent gate lines and retaining the transparent conductive layer below the gate lines; measuring the total second contact resistance (R B ); According to the first contact resistance (R A ) and the second contact resistance (R B ) calculate the contact resistance (R) between the transparent conductive layer and the doped silicon layer C ); and according to the contact resistance (R C )、Effective transmission distance (L T ), the width (W) of the unit cell to be tested and the width (d) of the gate line are used to calculate the contact resistivity (ρ) between the transparent conductive layer and the doped silicon layer.

[0005] In one embodiment of the present application, according to the first contact resistance (R A ) and the second contact resistance (R B ) to calculate the contact resistance (R C ) step includes calculating the contact resistance (R C ):

[0006] R C =R B -R A .

[0007] In one embodiment of the present application, according to the contact resistance (R C )、Effective transmission distance (L T ), the step of calculating the contact resistivity (ρ) based on the width (W) of the unit cell to be tested and the width (d) of the gate line includes calculating the contact resistivity (ρ) based on the following formula:

[0008]

[0009] In one embodiment of the present application, the effective transmission distance (L) is calculated based on the following formula: T ):

[0010]

[0011] Among them, the R Sh represents the resistance of the transparent conductive layer.

[0012] In one embodiment of the present application, the resistance (R Sh ) method comprises: measuring the resistance between the gate lines with different spacings; drawing a scatter plot with the resistance between the gate lines with different spacings and the corresponding spacings as the ordinate and abscissa, performing linear fitting on the scatter plot to obtain a fitting curve, wherein the slope of the fitting curve is k, and the resistance (R Sh ) is equal to the slope (k) multiplied by the width (W) of the unit cell to be tested.

[0013] In one embodiment of the present application, the width (W) of the unit battery cell to be tested is 0.8-1.0 cm.

[0014] In an embodiment of the present application, a method for removing the transparent conductive layer between adjacent gate lines includes: removing using a solution containing hydrochloric acid, removing using a laser, or removing using an etching paste.

[0015] In an embodiment of the present application, the doped silicon layer includes doped amorphous silicon and / or doped microcrystalline silicon.

[0016] In one embodiment of the present application, the unit cell to be tested does not have a main grid.

[0017] In one embodiment of the present application, the first contact resistance (R A ) and the second contact resistance (R B ).

[0018] Compared with the prior art, the present application has the following advantages: the measurement method of the present application does not require special sample preparation during the contact resistivity measurement process and directly uses mass-produced battery cells, thus having the advantage of a simple testing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0020] Figure 1 This is a process intention of a method for measuring the contact resistivity of a heterojunction battery in one embodiment of the present application;

[0021] Figure 2 A schematic cross-sectional view of a unit cell to be tested during the process of measuring contact resistivity in one embodiment of the present application;

[0022] Figure 3 yes Figure 2 A schematic top view of a unit cell to be tested;

[0023] Figure 4 is a schematic cross-sectional view of a unit cell to be tested during the process of measuring contact resistivity in one embodiment of the present application;

[0024] Figure 5 It is a fitting curve in one embodiment of the present application.

[0025] Reference numerals

[0026] A silicon substrate 210 , an intrinsic amorphous silicon layer 220 , a doped silicon layer 230 , a transparent conductive layer 240 and a gate line 250 . DETAILED DESCRIPTION

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0028] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0030] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0031] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0032] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0033] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0034] Next, the method for measuring the contact resistivity of the heterojunction battery of the present application is described through examples.

[0035] refer to Figure 1 The process diagram of a method for measuring the contact resistivity of a heterojunction battery in an embodiment shown in the figure, the heterojunction battery includes a doped silicon layer, a transparent conductive layer located on the doped silicon layer, and a plurality of grid lines arranged at intervals on the transparent conductive layer, and the measuring method in this embodiment includes the following steps S110 to S160:

[0036] S110: Slicing the battery cell to obtain a unit battery cell to be tested;

[0037] S120: Measure the first contact resistance (R A);

[0038] S130: removing the transparent conductive layer between adjacent gate lines, and retaining the transparent conductive layer below the gate lines;

[0039] S140: Measure the total second contact resistance (R B );

[0040] S150: According to the first contact resistance (R A ) and the second contact resistance (R B ) Calculate the contact resistance (R) between the transparent conductive layer and the doped silicon layer C );

[0041] S160: According to the contact resistance (R C )、Effective transmission distance (L T ), the width of the unit cell to be tested (W) and the width of the gate line (d) are used to calculate the contact resistivity (ρ) between the transparent conductive layer and the doped silicon layer.

[0042] Next, steps S110 to S160 will be described in detail.

[0043] refer to Figure 2 and Figure 3 As shown, the heterojunction cell includes a silicon substrate 210, an intrinsic amorphous silicon layer 220, a doped silicon layer 230, a transparent conductive layer 240, and a plurality of gate lines 250. The intrinsic amorphous silicon layer 220, the doped silicon layer 230, and the transparent conductive layer 240 are stacked on the silicon substrate 210, and the plurality of gate lines 250 are arranged at intervals on the transparent conductive layer 240, and the gate lines 250 are electrically connected to the transparent conductive layer 240. The doped silicon layer 230 may include doped amorphous silicon and / or doped microcrystalline silicon, for example, the doped silicon layer 230 may be N-type doped or P-type doped.

[0044] In step S110, the battery cell is diced to obtain a unit battery cell to be tested. The battery cell may be from mass-produced battery cells, for example, a mass-produced battery cell is randomly selected for dicing to prepare a unit battery cell to be tested.

[0045] refer to Figure 3 As shown, in one embodiment, the width (W) of the unit cell to be tested is any value within the range of 0.8 to 1.0 cm, for example, the width (W) is 0.8 cm, 0.9 cm or 1.0 cm. The unit cell to be tested does not have a main grid. It should be noted that the cell may have a main grid, and the main grid on the cell may be removed before or after dicing to obtain a unit cell to be tested without a main grid.

[0046] In step S120, the first contact resistance (RA The first contact resistance (R A ).

[0047] In step S130, refer to Figure 2 and Figure 4 As shown, the transparent conductive layer 240 between adjacent gate lines 250 in the horizontal direction is removed, and the transparent conductive layer 240 below the gate lines 250 is retained. The transparent conductive layer 240 between adjacent gate lines 250 in the horizontal direction can be removed using a solution containing hydrochloric acid, or by laser removal or etching paste.

[0048] In step S140, the total second contact resistance (R B The second contact resistance (R B ). The second contact resistance (R B ) is equal to the first contact resistance (R A ) plus the contact resistance (R C ).

[0049] In step S150, according to the first contact resistance (R A ) and the second contact resistance (R B ) Calculate the contact resistance (R) between the transparent conductive layer 240 and the doped silicon layer 230 C In one embodiment, according to the first contact resistance (R A ) and the second contact resistance (R B ) Calculate the contact resistance (R C ) step includes calculating the contact resistance (R C ):

[0050] R C =R B -R A

[0051] The contact resistance (R C ).

[0052] In step S160, according to the contact resistance (R C )、Effective transmission distance (L T), the width (W) of the unit cell to be tested and the width (d) of the gate line are used to calculate the contact resistivity (ρ) between the transparent conductive layer 240 and the doped silicon layer 230. The contact resistivity (ρ) can be calculated based on the following formula:

[0053]

[0054] The relevant data obtained in step S160 is substituted into the above formula to calculate the contact resistivity (ρ).

[0055] In one embodiment, the effective transmission distance (L) can be calculated based on the following formula: T ):

[0056]

[0057] Among them, R Sh represents the resistance of the transparent conductive layer 240 .

[0058] In one embodiment, the resistance (R Sh ) includes the following steps S310 and S320:

[0059] Step S310: measuring the resistance between the gate lines 250 with different spacings. Figure 3 As shown, the unit cell to be tested has 5 grid lines 250 arranged at intervals, and the intervals between the first grid line 250 on the left are L1, L2, L3, L4 and L5. The resistance between the grid lines 250 with different intervals is measured to obtain the resistance R corresponding to the intervals L1, L2, L3, L4 and L5 respectively. T1 , R T2 , R T3 , R T4 and R T5 , it is understandable that R T2 represents the resistance between the first gate line 250 and the third gate line 250 from the left (the distance between the first gate line 250 and the third gate line 250 is L2), R T1 , R T3 , R T4 and R T5 The meaning of R T2 Similar, I will not elaborate on this.

[0060] Step S320: Draw a scatter plot with the resistance between the gate lines with different spacings and the corresponding spacings as the ordinate and abscissa, and perform linear fitting on the scatter plot to obtain a fitting curve. The slope of the fitting curve is k, and the resistance of the transparent conductive layer (R Sh ) is equal to the slope (k) multiplied by the width (W) of the cell under test. Figure 5 As shown, RT1 , R T2 , R T3 , R T4 As the ordinate, draw a scatter plot with L1, L2, L3, and L4 as the abscissa, and then fit the scatter plot to obtain Figure 5 The slope of the fitting curve is k, and the slope (k) is related to the resistance (R Sh The relationship between the width (W) of the cell to be tested is shown below:

[0061]

[0062] Therefore, the resistance of the transparent conductive layer (R Sh ) is equal to the slope (k) multiplied by the width (W) of the unit cell to be tested. In addition, the intercept of the fitting curve is 2R C .

[0063] The above method of the present application does not require special sample preparation during the process of measuring contact resistivity, and directly uses mass-produced battery cells, so it has the advantage of a simple testing process.

[0064] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0065] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0066] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more application embodiments, in the above description of the embodiments of this application, multiple features are sometimes merged into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0067] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0068] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A method for measuring the contact resistivity of a heterojunction battery, wherein the heterojunction battery comprises a doped silicon layer, a transparent conductive layer located on the doped silicon layer, and a plurality of grid lines arranged at intervals on the transparent conductive layer, characterized in that: include: Slicing the battery cell to obtain a unit battery cell to be tested; Measure the first contact resistance (R A ); removing the transparent conductive layer between adjacent gate lines and retaining the transparent conductive layer below the gate lines; The total second contact resistance (R B ); According to the first contact resistance (R A ) and the second contact resistance (R B ) calculate the contact resistance (R) between the transparent conductive layer and the doped silicon layer C );as well as According to the contact resistance (R C )、Effective transmission distance (L T ), the width (W) of the unit cell to be tested and the width (d) of the gate line are used to calculate the contact resistivity (ρ) between the transparent conductive layer and the doped silicon layer.

2. The measuring method according to claim 1, characterized in that: According to the first contact resistance (R A ) and the second contact resistance (R B ) to calculate the contact resistance (R C ) step includes calculating the contact resistance (R C ): R C =R B -T A 。 3. The measuring method according to claim 1, characterized in that: According to the contact resistance (R C )、Effective transmission distance (L T ), the step of calculating the contact resistivity (ρ) based on the width (W) of the unit cell to be tested and the width (d) of the gate line includes calculating the contact resistivity (ρ) based on the following formula:

4. The measuring method according to claim 1, characterized in that: The effective transmission distance (L) is calculated based on the following formula T ): Among them, the R Sh represents the resistance of the transparent conductive layer.

5. The measuring method according to claim 4, characterized in that: Obtain the resistance (R Sh ) methods include: Measure the resistance between grid lines with different spacing; A scatter plot is drawn with the resistance between the gate lines with different spacings and the corresponding spacings as the ordinate and abscissa, and a linear fit is performed on the scatter plot to obtain a fitting curve, wherein the slope of the fitting curve is k, and the resistance (R Sh ) is equal to the slope (k) multiplied by the width (W) of the unit cell to be tested.

6. The measuring method according to claim 1, characterized in that: The width (W) of the unit battery cell to be tested is 0.8-1.0 cm.

7. The measuring method according to claim 1, characterized in that: Methods for removing the transparent conductive layer between adjacent gate lines include: removing with a solution containing hydrochloric acid, removing with a laser, and removing with an etching paste.

8. The measuring method according to claim 1, characterized in that: The doped silicon layer includes doped amorphous silicon and / or doped microcrystalline silicon.

9. The measuring method according to claim 1, characterized in that: The unit cell to be tested does not have a main grid.

10. The measuring method according to claim 1, characterized in that: The first contact resistance (R A ) and the second contact resistance (R B ).

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