阅读说明：本技术 一种钝化接触电池的电极金属化方法及电池、组件和系统 (Electrode metallization method for passivated contact battery, assembly and system ) 是由 陆俊宇 杜哲仁 沈承焕 陈嘉 于 2021-07-26 设计创作，主要内容包括：本发明公开了一种钝化接触电池的电极金属化方法及电池、组件和系统；该电极金属化方法：丝网印刷正面电极浆料后单独烧结,使正面电极的接触性达到最佳；而制备背面电极时,激光刻蚀部分掺杂多晶硅层,以精确控制接触窗口的深度和宽度,以免穿透隧穿氧化层而导致背面电极的接触复合变大、接触性能降低,再制备种子金属层以修补接触窗口的形貌缺陷,提供良好的导电层,使廉金属层分布更完整、均匀,优化接触性能,再配合电镀廉金属层及光诱导镀银,能获得更精细化的背面电极,减少背面遮光,且无需高温处理,不影响正面电极的接触性能,还能优化背面电极的接触复合及接触电阻。如此,能进一步优化电极接触性能,提高钝化接触电池的电池效率。(The invention discloses a method for metallizing an electrode of a passivated contact battery, a component and a system; the electrode metallization method comprises the following steps: screen printing front electrode slurry and then independently sintering to enable the contact of the front electrode to reach the best; when the back electrode is prepared, the laser etching part of the doped polycrystalline silicon layer is used for accurately controlling the depth and the width of the contact window so as to avoid the penetration of the tunneling oxide layer to cause the contact recombination of the back electrode to be enlarged and the contact performance to be reduced, then the seed metal layer is prepared to repair the shape defect of the contact window, a good conductive layer is provided, the distribution of the cheap metal layer is more complete and uniform, the contact performance is optimized, and then the electroplating of the cheap metal layer and the light-induced silver plating are matched, so that the more refined back electrode can be obtained, the back shading is reduced, the high-temperature treatment is not needed, the contact performance of the front electrode is not influenced, and the contact recombination and the contact resistance of the back electrode can be optimized. Thus, the electrode contact performance can be further optimized, and the cell efficiency of the passivated contact cell is improved.)

1. A method for metallizing an electrode of a passivated contact cell, comprising the steps of:

step 1, screen printing electrode slurry on a passivation anti-reflection layer on the front side of a battery with a passivation contact structure, and then sintering to enable the electrode slurry to burn through the passivation anti-reflection layer to form a front electrode contacting an emitter;

step 2, preparing a back electrode:

step 21, laser etching the antireflection film and part of the doped polycrystalline silicon layer on the back of the battery to form a contact window exposing the part of the etched doped polycrystalline silicon layer;

step 22, placing the battery in an acid solution containing a seed metal salt to prepare a seed metal layer at the contact window;

step 23, electroplating a base metal layer: placing the battery in electroplating solution, and forming a cheap metal layer on a contact window after the seed metal layer is prepared in an electroplating mode;

step 24, light-induced silver plating: the battery is placed in a silver salt solution, a front electrode of the battery is connected with a silver rod, the front electrode is used as a cathode, the silver rod is used as an anode, and photoproduction current is generated under illumination to drive silver to be deposited on the cheap metal layer, so that a back electrode is obtained.

2. A method of metallizing an electrode for passivating a contact cell according to claim 1, further comprising, prior to step 23, electroless nickel plating: and placing the battery in a solution containing nickel salt and a reducing agent, and sequentially performing oxidation-reduction reaction and low-temperature sintering on a contact window after the seed metal layer is prepared to obtain a nickel layer forming ohmic contact with the doped polycrystalline silicon layer.

3. The method of claim 2, wherein said low temperature sintering is: in N₂Sintering in atmosphere at 400 deg.C and 300-10 min.

4. The method of claim 1 or 2, wherein in step 23, the metal layer is made of copper;

the step of electroplating the metal layer of the base metal comprises the following steps:

light-induced copper plating: the cell is placed in a copper salt solution, a front electrode of the cell is connected with a copper source, the front electrode is used as a cathode, the copper source is used as an anode, photoproduction current is generated under the illumination condition, and copper is driven to deposit on a nickel layer to prepare the copper electrode.

5. A method of metallizing an electrode for passivating a contact cell according to claim 1 or 4, wherein an external power source is added during said light induction process to increase the deposition rate of light-induced plating.

6. A passivated contact cell characterized by a front electrode and a back electrode made by the method of electrode metallization of a passivated contact cell according to any of claims 1-5; the passivated contact cell comprises a silicon substrate, an emitter, a passivated antireflection layer and a front electrode, wherein the emitter, the passivated antireflection layer and the front electrode are sequentially arranged on the front surface of the silicon substrate, contact with the emitter and extend to the outside of the passivated antireflection layer; the antireflection film is provided with a contact window, the contact window is provided with a back electrode which extends into the doped polycrystalline silicon layer and extends out of the antireflection film, and the back electrode comprises a seed metal layer, a base metal layer and a silver layer which are sequentially arranged on the contact window.

7. A passivated contact cell according to claim 6 wherein the contact window has a width of 10-30 um.

8. A passivated contact cell according to claim 6 wherein the seed metal layer is a lead seed layer.

9. A passivated contact cell according to claim 6 wherein a nickel layer is further provided between the seed metal layer and the base metal layer, the base metal layer being a copper electrode provided between the nickel layer and the silver layer.

10. A passivated contact cell according to claim 9 wherein the copper electrode is located behind the nickel layer and extends beyond the antireflective coating and the silver layer overlies the surface of the copper electrode exposed beyond the antireflective coating.

11. A passivated contact cell according to claim 6 wherein the back electrode has a width of 10-40um and a height of 8-20 um.

12. The utility model provides a solar module, includes front material layer, front packaging layer, battery, back packaging layer and the back material layer that from top to bottom sets gradually, its characterized in that: the battery is a passivated contact battery according to any of claims 6 to 11.

13. A solar cell system comprising one or more solar cell modules, characterized in that: the solar cell module is one of the solar cell modules of claim 12.

Technical Field

The invention relates to the technical field of photovoltaic cells, in particular to an electrode metallization method of a passivated contact cell, a component and a system.

Background

The cell structure of the passivation contact cell (such as a TOPCon cell) comprises an ultrathin tunneling oxide layer and a doped polycrystalline silicon layer, so that the cell structure can obviously reduce metal contact recombination, has good contact performance and can greatly improve the efficiency of a photovoltaic cell. The cell structure has theoretical ultimate efficiency (namely 29.43%) closest to that of a crystalline silicon solar cell, and not only represents the highest technical level in the field of crystalline silicon cells at the present stage, but also is the development direction of next-generation crystalline silicon cells.

At present, the industrialization of the N-type double-sided TOPCon battery is realized, and the traditional electrode metallization method comprises the following steps: 1) printing paste (such as silver paste) on the anti-reflection film on the back surface of the battery by screen printing, and 2) co-sintering the paste on the back surface and the paste (such as silver-aluminum paste) printed on the front surface by screen printing in a belt sintering furnace, so that the paste is respectively contacted with the doped polycrystalline silicon layer and the emitter after burning through the anti-reflection film and the passivated anti-reflection layer, and the metallization process of the back electrode and the front electrode is completed. The conventional electrode metallization of such a double-sided TOPCon cell has the following disadvantages:

(a) the contact window is opened by etching the glass frit of the slurry at high temperature in the sintering process, the depth and the width of the etching cannot be accurately controlled, and an ideal window is difficult to obtain: insufficient sintering, insufficient opening of the window of contact, and thus poor contact; after sintering, the tunneling oxide layer of the passivated contact battery is only 1-2nm thick and is easily penetrated, so that contact recombination is increased, and the contact performance is reduced.

(b) Series resistance is one of the key parameters affecting cell efficiency, and is related to metallization, including the gold-half contact resistance of the electrode-to-cell substrate contact and the line resistance of the current flow through the electrode grid lines. In the traditional metallization mode, the burn-through performance of the slurry on the anti-reflection film on the back and a part of the n + doped polycrystalline silicon layer is considered, and the line resistance of the back electrode can not be considered, so that the efficiency of the battery is influenced.

(c) The front electrode and the back electrode have respective optimal sintering process curves, and the front electrode and the back electrode adopt a co-sintering mode, so that the respective optimal sintering temperatures of the front electrode and the back electrode cannot be taken into consideration, further the optimal contact resistance cannot be obtained, and the efficiency of the battery is influenced.

(d) Most of the components of the back electrode slurry are precious silver paste, so the cost is high.

(e) Limited by the screen printing technology, the height and width of the grid line of the electrode formed by the traditional metallization mode are difficult to control, a better grid line appearance cannot be obtained, the width of the grid line is usually greater than 30um, and the wider grid line can shield light, so that the back efficiency of the double-sided TOPCon battery is influenced.

In the prior art, for example, application No. CN201810090750.0 discloses a method for preparing a selective emitter black silicon polycrystalline PERC cell structure, which discloses an electrode metallization method as follows: laser windowing, screen printing and sintering are carried out on the back of the battery to prepare an aluminum back surface field, and after laser doping is carried out on the front of the battery to form a grid line, light-induced electroplating is carried out to form a front electrode. This method of electrode metallization suffers from the following drawbacks: the screen printing-sintering technology of the front electrode is not mature, and the cost performance is low; moreover, the electrode metallization method is not suitable for passivation contact cells, and even if the light-induced electroplating technology of the method is applied to the preparation of the back electrode of the passivation contact cell, it is difficult to prepare an ideal back electrode on the back of the passivation contact cell, and thus the contact performance of the passivation contact cell cannot be further optimized.

Disclosure of Invention

One of the objectives of the present invention is to provide an electrode metallization method for a passivated contact cell, which can make the passivated contact cell obtain ideal front and back electrodes to further optimize the contact performance, thereby improving the cell efficiency of the passivated contact cell and reducing the electrode cost, in view of the shortcomings of the electrode metallization method of the existing cell.

It is a further object of the present invention to provide a passivated contact cell with improved electrode contact performance, higher cell efficiency, and lower electrode cost.

The invention also aims to provide a solar cell module.

The fourth objective of the present invention is to provide a solar cell system.

Based on the above, the invention discloses an electrode metallization method for a passivated contact battery, which comprises the following preparation steps:

step 1, screen printing electrode slurry on a passivation anti-reflection layer on the front side of a battery with a passivation contact structure, and then sintering to enable the electrode slurry to burn through the passivation anti-reflection layer to form a front electrode contacting an emitter;

step 2, preparing a back electrode:

step 21, laser etching the antireflection film and part of the doped polycrystalline silicon layer on the back of the battery to form a contact window exposing the part of the etched doped polycrystalline silicon layer;

step 22, placing the battery in an acid solution containing a seed metal salt to prepare a seed metal layer at the contact window;

step 23, electroplating a base metal layer: placing the battery in electroplating solution, and forming a cheap metal layer on a contact window after the seed metal layer is prepared in an electroplating mode;

step 24, light-induced silver plating: the battery is placed in a silver salt solution, a front electrode of the battery is connected with a silver rod, the front electrode is used as a cathode, the silver rod is used as an anode, and photoproduction current is generated under illumination to drive silver to be deposited on the cheap metal layer, so that a back electrode is obtained.

Preferably, before step 23, electroless nickel plating is further included: and placing the battery in a solution containing nickel salt and a reducing agent, and sequentially performing oxidation-reduction reaction and low-temperature sintering on a contact window after the seed metal layer is prepared to obtain a nickel layer forming ohmic contact with the doped polycrystalline silicon layer.

Further preferably, the reaction temperature of the oxidation-reduction reaction is 25-80 ℃ and the reaction time is 1-5 min.

Further preferably, the low-temperature sintering is: in N₂Sintering in atmosphere, wherein the sintering temperature is 300-400 ℃, preferably 330-360 ℃, more preferably 350 ℃, and the sintering time is 3-10min, preferably 5 min.

Preferably, in step 23, the material of the metal layer is copper;

the step of electroplating the metal layer of the base metal comprises the following steps:

light-induced copper plating: the cell is placed in a copper salt solution, a front electrode of the cell is connected with a copper source, the front electrode is used as a cathode, the copper source is used as an anode, photoproduction current is generated under the illumination condition, and copper is driven to deposit on a nickel layer to prepare the copper electrode.

Further preferably, in step 232, the time for photo-induced copper plating is 15-40min, and the photo-generated current generated by illumination is 100-300 mA.

Preferably, in step 24, the light-induced silver plating time is 1-5min, and the photogenerated current generated by the light irradiation is 50-300 mA.

Wherein, in step 24, an external power source is added to accelerate the deposition rate of the light-induced silver plating; and/or, in step 232, increasing the external power source to accelerate the deposition rate of the photo-induced copper plating.

The invention also discloses a passivated contact cell, wherein the front electrode and the back electrode are prepared according to the electrode metallization method of the passivated contact cell; the passivated contact cell comprises a silicon substrate, an emitter, a passivated antireflection layer and a front electrode, wherein the emitter, the passivated antireflection layer and the front electrode are sequentially arranged on the front surface of the silicon substrate, contact with the emitter and extend to the outside of the passivated antireflection layer; the antireflection film is provided with a contact window, the contact window is provided with a back electrode which extends into the doped polycrystalline silicon layer and extends out of the antireflection film, and the back electrode comprises a seed metal layer, a base metal layer and a silver layer which are sequentially arranged on the contact window.

Preferably, the width of the contact window is 10-30um, preferably 18 um.

Preferably, the seed metal layer is a lead seed layer.

Preferably, a nickel layer is further disposed between the seed metal layer and the metal layer, and the metal layer is a copper electrode disposed between the nickel layer and the silver layer.

Further preferably, the copper electrode is arranged on the back of the nickel layer and extends out of the antireflection film, and the silver layer is arranged on the surface of the copper electrode exposed out of the antireflection film in a covering manner.

Preferably, the width of the back electrode is 10-40um, preferably 20um, and the height of the back electrode is 8-20um, more preferably 15 um.

The invention also discloses a solar cell module which comprises a front material layer, a front packaging layer, a cell, a back packaging layer and a back material layer which are sequentially arranged from top to bottom, wherein the cell is the passivated contact cell.

The invention also discloses a solar cell system which comprises one or more than one solar cell module, wherein the solar cell module is the solar cell module.

Compared with the prior art, the invention at least comprises the following beneficial effects:

1. according to the invention, the front electrode slurry is printed by screen printing and then sintered independently, so that the front electrode can reach an optimal sintering process curve, the front electrode slurry is burnt through the passivation anti-reflection layer and then contacts the emitter, and the contact performance of the front electrode is optimal; in addition, in the preparation process of the back electrode, the laser etching antireflection film and part of the doped polysilicon layer can accurately control the depth and the width of the contact window, so as to avoid the penetration of the doped polysilicon layer and the tunneling oxide layer to cause the contact recombination of the back electrode to be enlarged and the contact performance to be reduced, and before electroplating the metal layer, the seed metal layer can repair the shape defect of the contact window to provide a good conductive layer for the metal layer, so that the distribution of the metal layer is more complete and uniform, the contact performance of the back electrode is optimized, and the back electrode with narrower width and height can be obtained by matching with the electroplating of the metal layer and the light-induced silver plating, the shading of the back is reduced, and the electroplated metal layer and the photoinduction silver plating do not need high-temperature treatment, so that the contact performance of the front electrode is not influenced, and the contact recombination and the contact resistance of the back electrode of the passivated contact battery can be further optimized. Therefore, the passivated contact cell can simultaneously obtain ideal front electrodes and back electrodes so as to further optimize the contact performance of the passivated contact cell and further improve the cell efficiency of the passivated contact cell.

2. Compared with the screen printing-sintering technology for preparing the back electrode, the screen printing-sintering technology for the front electrode is relatively mature, and the cost performance is higher.

3. The main material of the back electrode is a cheap metal, high silver paste is replaced, and the cost of the electrode is reduced.

Drawings

Fig. 1 is a schematic structural diagram after step S1 in the method for metallizing an electrode of a passivated contact battery according to this embodiment.

Fig. 2 is a schematic structural diagram after step S2 in the method for metallizing an electrode of a passivated contact battery according to this embodiment.

Fig. 3 is a schematic structural diagram after step S3 in the method for metallizing an electrode of a passivated contact battery according to this embodiment.

Fig. 4 is a schematic structural diagram after step S4 in the method for metallizing an electrode of a passivated contact battery according to this embodiment.

Fig. 5 is a schematic structural diagram after step S5 in the method for metallizing an electrode of a passivated contact battery according to this embodiment.

Fig. 6 is a schematic structural diagram after step S6 in the method for metallizing an electrode of a passivated contact battery according to this embodiment.

Fig. 7 is a schematic structural diagram after step S7 in the method for metallizing an electrode of a passivated contact battery according to this embodiment.

The reference numbers illustrate: the solar cell comprises a silicon substrate 1, an emitter 2, a passivation antireflection layer 3, a front electrode 4, a tunneling oxide layer 5, a doped polycrystalline silicon layer 6, an antireflection film 7, a contact window 8, a back electrode 9, a seed metal layer 10, a nickel layer 11, a copper electrode 12 and a silver layer 13.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Examples

A method for passivating electrode metallization of a contact cell of the present embodiment, see fig. 1-7, includes the following preparation steps:

in step S1, a battery prepared by the conventional process is prepared without electrode metallization and with a passivated contact structure, the structure of which is shown in fig. 1.

Step S2, screen printing electrode paste on the passivation anti-reflective layer 3 on the front surface of the battery, and then sintering the electrode paste to burn through the passivation anti-reflective layer 3 at a high temperature to form the front electrode 4 contacting the emitter 2, which has the structure shown in fig. 2. Wherein, the electrode slurry of the front electrode 4 is silver slurry; since the screen printing-sintering technique for passivating the front electrode 4 of the contact cell is a conventional technique, it is not described in detail.

In step S3, the laser etching is used to etch the anti-reflection film 7 and part of the doped polysilicon layer 6 on the back of the cell to form a contact window 8, so as to expose the contact area of the partially etched doped polysilicon layer 6 at the contact window 8, while the other area on the back of the cell is still covered by the anti-reflection film 7, and the structure is shown in fig. 3.

Step S4, the battery is placed in an acid solution containing a seed metal salt to prepare a seed metal layer 10 at the contact window 8, the structure of which is shown in fig. 4.

In an example of this embodiment, the acidic solution containing the seed metal salt is a mixed solution of a seed metal chloride salt, HF, and HCl, and after the seed metal layer 10 is prepared, N is used₂And (5) drying the atmosphere.

Step S5, chemical nickel plating: placing the cell in a nickel-containing salt (e.g., NiSO)₄) And a reducing agent, and performing low-temperature sintering after the contact window 8 after the seed metal layer 10 is prepared is subjected to oxidation reduction reaction, so as to prepare a nickel layer 11 which forms ohmic contact with the doped polycrystalline silicon layer 6, wherein the structure of the nickel layer is shown in figure 5. The nickel layer 11 can be efficiently and rapidly prepared by chemical plating. It should be noted that, in the chemical nickel plating, nickel salt and solution are oxidized and reduced to deposit nickel, so that the nickel covers the surface of the seed metal layer 10, and the deposited nickel is sintered and doped at low temperatureThe polycrystalline silicon layer 6 forms nickel-silicon alloy of ohmic contact, namely a nickel layer 11, and at the moment, the seed metal layer 10 only exists at the shape defect of the contact window 8, so that the nickel layer 11 is distributed more completely and uniformly.

Wherein the reaction temperature of the oxidation-reduction reaction is 25-80 ℃, and the reaction time is 1-5 min. The conditions of the low-temperature sintering are as follows: in N₂Sintering in atmosphere, wherein the sintering temperature is 300-400 ℃, preferably 330-360 ℃, more preferably 350 ℃, and the sintering time is 3-10min, preferably 5 min.

Step S6 is to form a metal layer on the surface of nickel layer 11 by electroplating. The material of the metal layer is preferably copper, and the plating method of copper is preferably light-induced plating. The method comprises the following specific steps:

light-induced copper plating: the cell is placed in a copper salt (e.g. CuSO)₄) In the solution, the front electrode 4 of the cell is connected to a copper source (e.g., a copper rod), the front electrode 4 is used as a cathode, the copper source is used as an anode, and photo-generated current is generated under the illumination condition to drive copper to deposit on the nickel layer 11 to obtain a copper electrode 12, which has a structure shown in fig. 6. Wherein, the time of light-induced copper plating is 15-40min, and the photo-generated current generated by illumination is 100-300 mA.

Step S7, light-induced silver plating: the cell is placed in a silver salt solution, a front electrode 4 of the cell is connected with a silver rod, the front electrode 4 is used as a cathode, the silver rod is used as an anode, and photoproduction current is generated under illumination to drive silver to be deposited on a cheap metal layer, namely a back electrode 9, wherein the structure of the back electrode is shown in fig. 7. Wherein, the time of light induction silvering is 1-5min, and the photoproduction current generated by illumination is 50-300 mA.

The effect of the method for metallizing an electrode of a passivated contact cell in this embodiment is as follows:

the front electrode 4 slurry is independently sintered after being screen-printed, so that the front electrode 4 can reach an optimal sintering process curve, the front electrode 4 slurry is burnt through the passivation anti-reflection layer 3 and then contacts the emitter 2, and the contact performance of the front electrode 4 is optimal; moreover, in the preparation process of the back electrode 9, the laser etching antireflection film 7 and part of the doped polysilicon layer 6 can accurately control the depth and the width of the contact window 8, so as to prevent the doped polysilicon layer 6 and the tunnel oxide layer 5 from penetrating to cause the contact recombination of the back electrode 9 to be enlarged and the contact performance to be reduced, and before electroplating the metal layer, the seed metal layer 10 is prepared to repair the shape defect of the contact window 8, provide a good conductive layer for the metal layer, so that the distribution of the electroplated metal layer is more complete and uniform, the contact performance of the back electrode 9 is optimized, and the back electrode 9 with narrower width and height can be obtained by matching with the electroplated metal layer and the light-induced silver plating, the shading of the back is reduced, and the electroplating of the metal layer and the light-induced silver plating do not need high-temperature treatment, so that the contact performance of the front electrode 4 is not influenced, and the contact recombination and the contact resistance of the back electrode 9 of the passivated contact battery can be further optimized. Thus, the passivated contact cell can simultaneously obtain the ideal front electrode 4 and back electrode 9 to further optimize the contact performance of the passivated contact cell, and further improve the cell efficiency of the passivated contact cell.

Moreover, compared with the screen printing-sintering process for preparing the back electrode 9, the screen printing-sintering process for preparing the front electrode 4 is relatively mature, and therefore, the front electrode 4 prepared by the present embodiment has higher cost performance.

In a passivated contact cell of this embodiment, the front electrode 4 and the back electrode 9 are formed according to the electrode metallization method of steps S1-S7 described above; as shown in fig. 1-7, the passivated contact cell includes a silicon substrate 1, an emitter 2, a passivated antireflection layer 3, and a front electrode 4 contacting the emitter 2 and extending to the outside of the passivated antireflection layer 3, which are sequentially disposed on the front surface of the silicon substrate 1, a tunneling oxide layer 5, a doped polysilicon layer 6, and an antireflection film 7, which are sequentially disposed on the back surface of the silicon substrate 1; the antireflection film 7 is provided with a contact window 8, the contact window 8 is provided with a back electrode 9 which extends into the doped polycrystalline silicon layer 6 and extends out of the antireflection film 7, and the back electrode 9 comprises a seed metal layer 10, a base metal layer and a silver layer 13 which are sequentially arranged on the contact window 8.

To further ensure the quality and cell efficiency of the passivated contact cell, the passivated contact cell is preferably an N-type double-sided TOPCon cell, the silicon substrate 1 is preferably an N-type crystalline silicon, the emitter 2 is a doped p + emitter, the doped polysilicon layer 6 is an N + doped polysilicon layer, the antireflective film 7 is preferably a SiNx antireflective film, the passivated antireflective layer 3 is preferably an AlOx/SiNx stacked passivated antireflective layer, i.e. the passivated antireflective layer 3 comprises an AlOx film and a SiNx film sequentially arranged on the emitter 2.

The width of the contact window 8 is 10-30um, preferably 15-25um, more preferably 18um, so that the narrower contact window 8 and the back electrode 9 can be obtained on the premise of not influencing the contact performance of the back electrode 9, so as to reduce back shading and further improve the battery efficiency of the passivated contact battery. The height of the contact window 8 is based on the height required for the back electrode 9 to extend into the doped polysilicon layer 6 (without penetrating the doped polysilicon layer 6) and extend to the outside of the anti-reflection film 7, so as to prevent the back electrode 9 from penetrating the doped polysilicon layer 6 and the tunnel oxide layer 5 to cause the contact recombination to be enlarged and the contact performance to be reduced.

Wherein, a nickel layer 11 is also arranged between the seed metal layer 10 and the base metal layer. The seed metal layer 10 is preferably a lead seed layer, which can repair the shape defects of the contact window 8, provide a good conductive layer for the nickel layer 11 and the metal layer, so that the nickel layer 11 and the metal layer are distributed more completely and uniformly, optimize the contact performance of the front electrode 4, and the lead seed layer has low price, and can reduce the cost of the back electrode 9.

Wherein the metal layer is a copper electrode 12 arranged between the nickel layer 11 and the silver layer 13. The nickel layer 11 can better form ohmic contact with the doped polysilicon layer 6, and can prevent the copper electrode 12 from polluting the silicon substrate 1 to influence contact recombination, and the copper electrode 12 is used as a main material of the back electrode 9, so that high silver paste can be replaced, and the electrode cost is greatly reduced.

Preferably, the copper electrode 12 is disposed on the back of the nickel layer 11 and extends to the outside of the antireflective coating 7, and the silver layer 13 covers the surface of the copper electrode 12 exposed to the outside of the antireflective coating 7, so that the silver layer 13 can better protect the copper electrode 12 from being oxidized, and the silver layer 13 can also be responsible for being connected with a solder strip during later manufacturing of the solar cell module.

Wherein, the width of the back electrode 9 is 10-40um, preferably 15-30um, more preferably 20um, and the height of the back electrode 9 is 8-20um, preferably 10-15um, more preferably 15 um; thus, the width of the back electrode 9 is narrow, and back light shielding can be reduced.

The passivated contact cell of the embodiment can prepare the ideal back electrode 9 on the passivated contact structure so as to further optimize the contact recombination and contact performance of the back electrode 9 and further improve the cell efficiency of the passivated contact cell.

Tests show that the open-circuit voltage of a conventional passivated contact cell obtained by using the electrode metallization of the traditional screen-printed co-sintered front electrode and back electrode is 703mV, and the short-circuit current density is 40.78mA/cm²The fill factor was 82.75%, the cell efficiency was 23.72%, and the double-sided rate was 80.23%. In contrast, a passivated contact cell made in this example had an open circuit voltage of 709mV and a short circuit current density of 40.98mA/cm²The filling factor is 83.38%, the battery efficiency is improved to 24.23%, and the double-sided rate is up to 84.42%. Therefore, the contact performance, the battery efficiency and the double-sided rate of the passivated contact battery prepared by the embodiment are obviously improved.

While preferred embodiments of the present invention have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.

The technical solutions provided by the present invention are described in detail above, and the principle and the implementation of the present invention are explained in this document by applying specific examples, and the descriptions of the above examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.