Process method for passivating and contacting auxiliary battery at component end

Abstract

The invention relates to the technical field of solar photovoltaic modules, and particularly discloses a process method for passivating and contacting an auxiliary battery at a module end. The process method comprises the following steps: after battery pieces are subjected to series welding, lamination and packaging to form a battery assembly, the battery assembly is placed in an environment box for illumination, the temperature is set to be 50-75 DEG C, the irradiance is 1000-1500 Wh / m < 2 >, the forward current is 2-5 A, and illumination is carried out for 1-4 h. Under the conditions of high irradiance, medium temperature and low current, the battery piece adopting the LECO technology has a good internal defect repairing effect, contact between a metal electrode and silicon can be optimized again, the FF value and the Voc value of the battery assembly are improved, and therefore the power of the battery assembly is remarkably increased; and the contact resistance and passivation effect can be optimized at the component end in an auxiliary manner, so that the component power is improved, novel equipment does not need to be added on a production line, and the production efficiency is not influenced.

Description

Technical Field

[0001] The invention relates to the technical field of solar photovoltaic modules, and particularly discloses a process for passivation and contact of auxiliary cells at module ends. Background Art

[0002] With the development of solar cell technology, the development of high-efficiency cells and high-efficiency modules has received increasing attention. n-Topcon cells have attracted much attention from researchers at home and abroad due to their low process temperature, high conversion efficiency, good cell stability and low temperature coefficient. How to further improve module power at the module manufacturing end has also become a focus of the industry.

[0003] Currently, LECO technology (laser-assisted sintering) has been added to the battery to increase cell efficiency. LECO technology uses a specialized silver paste (the original Topcon battery used a silver-aluminum paste on the front). Lasers precisely heat the silver paste, locally destroying the passivation layer. Under the influence of high temperature, the silver particles begin to react with silicon, locally forming a silver-silicon alloy. This alloy junction has a low contact resistance.

[0004] However, the battery end cannot optimize the contact resistance and passivation effect of the packaged components. To address this situation, Aikon first improved light injection and published patent CN114122197A, which mainly involves adding light injection after the lamination process. The light injection process is completed after lamination and before testing. The component has a temperature of 150°C after lamination. The light injection equipment is heated to a certain temperature to achieve the effect of light injection. After the light injection equipment is docked with the laminator, it has a certain temperature after lamination. On this basis, it will be better able to accept light injection when entering the light injection equipment, thereby achieving a better effect of improving power output. However, this method is only applicable to cells that did not have LECO technology before, and mainly acts on heterojunction cells. It also requires the addition of new equipment to the production line, which increases costs and affects production efficiency. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a process for assisting battery passivation and contact at the component end.

[0006] The present invention discloses a process for passivation and contacting of auxiliary cells at the module end, which adopts the following technical solutions:

[0007] A process for assisting battery passivation and contact at the component end. After the battery cells are serially welded, laminated, and packaged to form a battery assembly, the battery assembly is placed in an environmental chamber for light exposure, with a set temperature of 50°C to 75°C and an irradiance of 1000Wh / m 2 ~1500Wh / m 2 , the forward current is 2 to 5A, and the light exposure is 1 to 4 hours.

[0008] Preferably, the process is directed to a battery assembly composed of battery cells using LECO technology.

[0009] Preferably, the process is directed to a battery assembly composed of battery cells using LECO technology-specific silver paste.

[0010] Preferably, the battery assembly is placed in an environmental chamber with a temperature of 50°C and an irradiance of 1000Wh / m 2 , the forward current is 3A.

[0011] Preferably, the battery assembly is placed in an environmental chamber with a temperature of 60°C and an irradiance of 1000Wh / m 2 , the forward current is 2.5A.

[0012] Preferably, the battery assembly is placed in an environmental chamber with a temperature of 55°C and an irradiance of 1000Wh / m 2 , the forward current is 4A.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects:

[0014] 1. By having a good internal defect repair effect on cells using LECO technology under high irradiance, medium temperature and low current conditions, the cell passivation effect is improved. In addition, the contact between the metal electrode and silicon can be further optimized, and the FF value and Voc value of the battery module can be improved, thereby significantly increasing the power of the battery module;

[0015] 2. The process method of the present invention can assist in optimizing the contact resistance and passivation effect at the component end, thereby improving the component power without adding new equipment to the production line and without affecting production efficiency. DETAILED DESCRIPTION

[0016] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific embodiments.

[0017] After solar cell manufacturing and lamination, their electrical performance typically reaches its peak, after which it will begin to decline due to environmental factors and other factors. For existing LECO (laser-assisted sintering) cells, a special process is used at the module end to further enhance the cell passivation and contact quality, thereby increasing module power.

[0018] Example 1

[0019] This embodiment discloses a process for assisting the passivation and contacting of the battery at the module end. After the battery cells are serially soldered, laminated, and packaged to form a battery module, the battery module is subjected to a power test and then placed in an environmental chamber for light exposure, with the temperature set at 50°C and the irradiance at 1000Wh / m 2 , the forward current is 3A, and the light is on for 2 hours. After the light is on, the temperature is cooled down and the power test is performed after the component temperature drops to the standard test temperature.

[0020] Example 2

[0021] This embodiment discloses a process for assisting the passivation and contacting of the battery at the module end. After the battery cells are serially soldered, laminated, and packaged to form a battery module, the battery module is subjected to a power test and then placed in an environmental chamber for light exposure, with the temperature set at 60°C and the irradiance at 1000Wh / m 2 The forward current was 2.5A and the illumination was carried out for 2 hours. After the illumination, the temperature was cooled down and the power test was carried out after the component temperature dropped to the standard test temperature.

[0022] Example 3

[0023] This embodiment discloses a process for assisting the passivation and contacting of the battery at the module end. After the battery cells are serially soldered, laminated, and packaged to form a battery module, the battery module is subjected to a power test and then placed in an environmental chamber for light exposure, with the temperature set at 55°C and the irradiance at 1000Wh / m 2 The forward current was 4A and the illumination was 2 hours. After the illumination, the temperature was cooled down and the power test was performed after the component temperature dropped to the standard test temperature.

[0024] Performance testing:

[0025] Test 1: The process of the present invention is used to compare the power data of batteries that have undergone LECO technology and batteries that have not undergone LECO technology:

[0026] Table 1

[0027]

[0028] As shown in Table 1, it can be seen that after using LECO batteries, the module power increases by 3-5W, while the power of batteries without LECO technology remains basically unchanged.

[0029] Test 2: The process method of the present invention and the process method of the prior art were used on LECO battery modules to compare their power:

[0030] Table 2

[0031]

[0032] As shown in Table 2, it can be seen that the power of the battery assembly is relatively improved by adopting the process method of the present invention under the conditions of high irradiance, medium temperature and weak current, while the power of the battery assembly is relatively reduced by adopting the process method of the prior art under the conditions of ultra-high irradiance, high ambient temperature and strong current.

[0033] Test 3: Verify the impact of current changes on module power in the process of the present invention

[0034] Table 3

[0035]

[0036] As shown in Table 3, it can be seen that in the process method of the present invention, the current value during the light treatment should not be too large or too small. When the current value is 7A, the power only increases by less than 1W, and the improvement effect is not obvious. When the current value is 1A, the power basically does not change. Only under a weak current of 2 to 5A can the atoms with poor adhesion in the passivation layer escape, thereby better improving the passivation effect and achieving a better increase in the power of the battery component.

[0037] Under conditions of high irradiance, medium temperature, and low current, the process of this invention can, to a certain extent, better repair internal defects in cells using LECO technology, resulting in improved cell passivation. It can also further optimize the contact between the metal electrode and the silicon body, significantly improving the FF value of the cell module and slightly increasing Voc. This reduces the series resistance and increases the parallel resistance of the cells using LECO technology, thereby increasing the power of the cell module. This process also eliminates the need to add new equipment to the production line, which does not affect production efficiency.

[0038] On the one hand, although LECO technology can accurately destroy the passivation layer of the solar cell, the passivation layer will still be slightly damaged. Under appropriate environmental conditions, as the temperature gradually rises to the range of 50℃ to 75℃, and an appropriate weak current of 2 to 5A is added, the atoms that originally had poor adhesion in the passivation layer will escape, and the corresponding minority carrier lifetime of the silicon wafer will be slightly increased, the passivation effect will be enhanced, and Voc will be slightly improved;

[0039] On the other hand, LECO technology uses a special pure silver paste, which has better current transmission properties. Under high irradiance conditions, the contact resistance of the current generated by photons passing through the gate line will be reduced, so the FF value will be greatly improved.

[0040] The technical solution provided by the present invention is introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A process for assisting battery passivation and contact at the component end, characterized in that: After the battery cells are serially welded, laminated, and packaged to form a battery assembly, the battery assembly is placed in an environmental chamber for illumination, with the temperature set at 50°C to 75°C and the irradiance at 1000Wh / m 2 ~1500Wh / m 2 , the forward current is 2 to 5A, and the light exposure is 1 to 4 hours.

2. A process for passivation and contacting of auxiliary cells at the module end according to claim 1, characterized in that: This process is targeted at battery assemblies composed of battery cells using LECO technology.

3. A process for passivation and contacting of auxiliary cells at the module end according to claim 2, characterized in that: This process is targeted at battery assemblies composed of cells using LECO technology-specific silver paste.

4. The process for passivation and contacting of auxiliary cells at the module end according to claim 1, characterized in that: The battery assembly was placed in an environmental chamber with a temperature of 50°C and an irradiance of 1000Wh / m 2 , the forward current is 3A.

5. The process for passivation and contacting of auxiliary cells at the module end according to claim 1, characterized in that: The battery assembly was placed in an environmental chamber with a temperature of 60°C and an irradiance of 1000Wh / m 2 , the forward current is 2.5A.

6. The process for passivation and contacting of auxiliary cells at the module end according to claim 1, characterized in that: The battery assembly was placed in an environmental chamber with a temperature of 55°C and an irradiance of 1000Wh / m 2 , the forward current is 4A.

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