An ultrasonic-assisted crystalline silicon cell glass separation and EVA recovery method

Abstract

The present invention discloses an ultrasonic-assisted crystalline silicon cell glass separation and EVA recovery method, comprising the following steps: removing and fixing the aluminum frame and junction box of the photovoltaic panel; using an ultra-low temperature ethanol solution to embrittle the EVA packaging material on the lower surface of the glass, using ultrasonic vibration to remove the embrittled EVA, and separating the glass and the ethanol solution containing EVA powder; heating and distilling the separated ethanol solution, collecting and recovering the pure ethanol after distillation, and obtaining the remaining pure EVA. The present invention adopts a combined method of low-temperature embrittlement and ultrasonic vibration, replacing traditional chemical reagent immersion and heat treatment methods, avoiding the discharge of waste liquid and gaseous pollutants, and is beneficial to environmental protection.

Description

Technical Field

[0001] The invention relates to the classification and recycling of solar cell panel resources, and in particular to an ultrasonic-assisted crystalline silicon cell glass separation and EVA recycling method. Background Art

[0002] Solar energy is a green renewable resource that helps achieve the dual carbon goals. With the development of the solar photovoltaic industry, the amount of scrapped photovoltaic modules has also increased dramatically. It is predicted that by 2050, my country's discarded photovoltaic modules will reach 20 million tons. Crystalline silicon solar panels contain abundant renewable resources and have high recycling value. How to recycle and reuse discarded crystalline silicon solar panels is imminent.

[0003] At present, the main recycling methods of photovoltaic modules are: physical separation, organic solvent dissolution method, heat treatment method, etc. Physical separation first removes the aluminum frame and junction box, then crushes the frameless module, separates the solder strip and glass particles, and then grinds the remaining part to obtain metal, silicon powder, backplane particles and EVA particles by electrostatic separation method. This method is not perfect and fails to achieve the separation of a single component. The organic solvent dissolution method refers to the use of organic solvents to dissolve the packaging material EVA to achieve the purpose of separating the battery cell, EVA, glass and backplane. This method takes a long time, and the battery cell breaks after the EVA expands, and there are problems such as difficulty in treating organic waste liquid. The heat treatment method is to put the photovoltaic module into an incinerator or a muffle furnace, burn it to remove the packaging material EVA, and after the incineration is completed, the battery, glass and frame are manually separated. This method does not burn completely and is prone to produce more gaseous pollutants. In addition, the current photovoltaic module recycling method mainly considers the removal of the packaging material EVA, and rarely involves the recycling of EVA. From 2013 to 2019, the growth rate of EVA supply in China was around 11%, which was slower than the growth rate of photovoltaic modules, and the growth rate of photovoltaic-grade EVA supply was even lower. Therefore, the mismatch between EVA supply and demand for many consecutive years has led to a continuous rise in EVA prices.

[0004] The impact absorption energy of the material decreases as the temperature decreases. When the test temperature is lower than the critical transition temperature of toughness and brittleness, the impact absorption energy decreases significantly, and the material changes from a tough state to a brittle state. This phenomenon is called low-temperature brittleness. The brittle temperature of the packaging material EVA is about -70°C, which is higher than tempered glass and crystalline silicon. Ultrasonic vibration utilizes the positive and negative pressure alternation cycle that exists during the transmission of ultrasonic waves. In the positive phase, it squeezes the medium molecules and increases the original density of the medium; in the negative phase, the medium molecules are sparse and discrete, and the medium density decreases. Summary of the invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the background technology, the present invention discloses an ultrasonic-assisted crystalline silicon cell glass separation and EVA recovery method.

[0006] Technical solution: The ultrasonic-assisted crystalline silicon cell glass separation and EVA recovery method disclosed in the present invention comprises the following steps:

[0007] S1. Remove the aluminum frame and junction box of the photovoltaic panel and fix them;

[0008] S2, using an ultra-low temperature ethanol solution to embrittle the EVA packaging material on the lower surface of the glass, using ultrasonic vibration to remove the embrittled EVA, and separating the glass and the ethanol solution containing EVA powder;

[0009] S3, heating and distilling the separated ethanol solution, collecting and recovering the pure ethanol after distillation, and obtaining the remaining pure EVA at the same time.

[0010] Among them, in S1, a vacuum adsorption plate is used to adsorb and fix the back plate of the photovoltaic panel.

[0011] Furthermore, the ultra-low temperature ethanol solution used in S2 is -70°C to -80°C.

[0012] Furthermore, 25KHZ to 35KHZ ultrasonic vibration is used in S2.

[0013] Furthermore, in S2, ethanol embrittlement and ultrasonic vibration are performed simultaneously, or ethanol embrittlement is performed first and then ultrasonic vibration.

[0014] Furthermore, distillation is carried out by heating at 80°C in S3.

[0015] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0016] 1. The combined method of low-temperature embrittlement and ultrasonic vibration is used to replace traditional chemical reagent immersion and heat treatment methods, avoiding the discharge of waste liquid and gaseous pollutants, which is beneficial to environmental protection;

[0017] 2. The present invention adopts a heating distillation method to separate pure ethanol and EVA, thereby realizing resource recycling;

[0018] 3. Low-temperature embrittlement and ultrasonic vibration are achieved through ultra-low-temperature ethanol and ultrasonic generator respectively. The separation and recovery process is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a technical flow chart of the present invention;

[0020] Figure 2 This is a structural diagram of the ultrasonic vibrator and the ultra-low temperature ethanol injection pipe of the present invention;

[0021] Figure 3 It is a structural diagram of the collecting tank of the present invention. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] Example 1

[0024] like Figure 1 The ultrasonic-assisted crystalline silicon cell glass separation and EVA recovery method shown comprises the following steps:

[0025] S1. Remove the aluminum frame and junction box of the photovoltaic panel, and use a vacuum adsorption plate to adsorb and fix the back plate of the photovoltaic panel. The diameter of the vacuum adsorption plate is 0.2 times the width of the photovoltaic panel and is distributed diagonally on the back plate.

[0026] S2, using -80°C ultra-low temperature ethanol solution to embrittle the EVA packaging material on the lower surface of the glass, using 35KHZ ultrasonic vibration to remove the embrittled EVA, and separating the glass and the ethanol solution containing EVA powder;

[0027] like Figure 2 As shown, an ultrasonic vibrator 1 and an ultra-low temperature ethanol injection pipe 2 are connected in parallel to an ultrasonic generator 3 and a low temperature ethanol storage tank 4 respectively. A speed regulating valve 5 is provided on the ultrasonic vibrator 1 and the ultra-low temperature ethanol injection pipe 2. The ultrasonic vibrator 1 and the ultra-low temperature ethanol injection pipe 2 are held by a handle 6 to spray simultaneously.

[0028] like Figure 3 As shown, the ethanol solution containing EVA powder is collected by two baffles 8 with a collecting tank 7 in the middle.

[0029] S3, heating the separated ethanol solution to 80°C for distillation, collecting and recovering the pure ethanol after distillation, and obtaining the remaining pure EVA.

[0030] Example 2

[0031] S1. Remove the aluminum frame and junction box of the photovoltaic panel and fix them.

[0032] S2. The EVA packaging material on the lower surface of the glass is embrittled by using an ultra-low temperature ethanol solution at -70°C for 2 minutes, and then the embrittled EVA is removed by 25KHZ ultrasonic vibration to separate the glass and the ethanol solution containing EVA powder.

[0033] S3, heating the separated ethanol solution to 80°C for distillation, collecting and recovering the pure ethanol after distillation, and obtaining the remaining pure EVA.

Claims

1. An ultrasonic-assisted crystalline silicon cell glass separation and EVA recovery method, characterized in that: The following steps are involved: S1. Remove the aluminum frame and junction box of the photovoltaic panel and fix them; S2, using an ultra-low temperature ethanol solution to embrittle the EVA packaging material on the lower surface of the glass, using ultrasonic vibration to remove the embrittled EVA, and separating the glass and the ethanol solution containing EVA powder; S3, heating and distilling the separated ethanol solution, collecting and recovering the pure ethanol after distillation, and obtaining the remaining pure EVA; Among them, in S1, a vacuum adsorption plate is used to adsorb and fix the back plate of the photovoltaic panel; The ultra-low temperature ethanol solution used in S2 is -70℃~-80℃; ethanol embrittlement and ultrasonic vibration are carried out simultaneously, or ethanol embrittlement is carried out first and then ultrasonic vibration; 25KHZ~35KHZ ultrasonic vibration is used; S2 is realized by an ultrasonic vibrator (1) and an ultra-low temperature ethanol injection pipe (2) connected in parallel, which are respectively connected to an ultrasonic generator (3) and a low temperature ethanol storage tank (4). The ultrasonic vibrator (1) and the ultra-low temperature ethanol injection pipe (2) are both provided with a speed regulating valve (5) which is controlled by a handle (6).

2. The ultrasonic-assisted crystalline silicon cell glass separation and EVA recovery method according to claim 1, characterized in that: In S3, distillation was carried out by heating at 80°C.

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