Flame-retardant disassembling agent of polyurethane adhesive and lossless disassembling method of power battery pack

Abstract

The invention discloses a flame-retardant disassembling agent of polyurethane glue and a lossless disassembling method of a power battery pack. The flame-retardant disassembling agent consists of a solvent, a catalyst, a cocatalyst and a de-crosslinking agent, wherein the solvent is a flame-retardant or incombustible halogenated hydrocarbon liquid having affinity with polyurethane, and the catalyst is an antimony or organic alkali catalyst capable of catalyzing transesterification. According to the flame-retardant polyurethane adhesive disclosed by the invention, through the synergistic effect of all the components, efficient debonding and degradation of the polyurethane adhesive can be realized, and the flame-retardant polyurethane adhesive has excellent flame-retardant property, so that safety accidents possibly caused by inflammability of a conventional solvent are avoided, and the fire risk in practical application is effectively reduced. The flame-retardant disassembling agent can be used for separating a battery cell from a polyurethane adhesive in a power battery pack, realizes rapid and lossless disassembly of the battery pack under a mild condition, and has a large-scale application prospect.

Description

Technical Field

[0001] This invention belongs to the field of power battery recycling technology, and specifically relates to a flame-retardant dismantling agent for polyurethane adhesive and a non-destructive dismantling method for power battery packs. Background Technology

[0002] Currently, the main types of power batteries on the market are lithium batteries. To improve energy density, reduce weight, and lower costs, most power batteries use polyurethane structural adhesive to bond and fix the cells to each other and to the casing, and polyurethane thermally conductive adhesive to improve heat dissipation. While this design meets the structural strength and heat dissipation requirements of the battery pack during its service life, it presents significant challenges for the recycling and dismantling of retired batteries. During battery recycling, the bonded cells and structural components must be separated without damage or with minimal damage in order to allow for the testing, sorting, and reuse of valuable cells.

[0003] Existing methods for recycling and dismantling power batteries mainly include the following: 1) Mechanical dismantling: This method uses physical means such as cutting and prying to separate the battery cells from the polyurethane structural adhesive and structural components. However, this method easily damages the battery cells, leading to internal short circuits and even thermal runaway, posing safety risks. 2) Freezing dismantling: This method involves freezing the battery pack to below -30°C to embrittle the polyurethane adhesive before hammering. This method is energy-intensive, inefficient, and the rapid temperature change can cause irreversible damage to the battery cells, hindering their reuse. 3) Chemical dismantling: This method involves immersing the battery pack in a dismantling agent composed of organic solvents and catalysts. Under relatively mild conditions, the chemical structure of the polyurethane adhesive is destroyed, causing it to lose its adhesive strength, thus achieving non-destructive separation of the battery pack components. This method can non-destructively separate the battery cells from the structural components, enabling the reuse of the battery cells.

[0004] However, current chemical dismantling methods pose significant safety risks. This is because retired power batteries themselves carry a risk of fire due to thermal runaway during dismantling. Commonly used organic solvents are flammable, thus creating safety hazards. For example, CN 118970262 A discloses a method for removing the sealing structural adhesive from the surface of blade batteries in a power battery pack. This method uses N,N-dimethylformamide and N-methylpyrrolidone at specific concentrations to prepare a de-adhesive agent. The polyurethane structural adhesive in the battery pack is then immersed in the de-adhesive agent, and the blade batteries can be separated after several hours. The solvents in this de-adhesive agent are mostly flammable or combustible liquids with low flash points and high volatility. During dismantling, high-temperature open flames generated by battery thermal runaway, or static sparks generated during operation, can easily ignite these flammable solvents.

[0005] Existing chemical dismantling technologies pose safety hazards. Developing a flame-retardant dismantling agent that possesses both high-efficiency dismantling capabilities and is inherently non-flammable or even non-flammable has become a key technological bottleneck in promoting the safe and green recycling industry of power batteries. Therefore, there is an urgent need in this field for a dismantling solution that can fundamentally address the safety hazards of battery dismantling. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a flame-retardant dismantling agent for polyurethane adhesives and a non-destructive dismantling method for power battery packs. This flame-retardant dismantling agent not only achieves efficient degradation of polyurethane adhesives under mild conditions but also possesses flame retardancy and good safety, thus eliminating safety hazards caused by flammable solvents. Furthermore, this flame-retardant dismantling agent can be recycled and reused, showing promise for large-scale practical application.

[0007] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution:

[0008] The first objective of this invention is to provide a flame-retardant disintegrating agent for polyurethane adhesives, wherein, by weight, the flame-retardant disintegrating agent comprises 100 parts solvent, 0.1-15 parts catalyst, 0.1-15 parts co-catalyst, and 0.1-30 parts de-crosslinking agent;

[0009] The solvent is a flame-retardant or non-flammable halogenated hydrocarbon liquid with affinity for polyurethane polymers. Its core function is to rapidly wet and swell the polyurethane crosslinking network, providing a pathway for subsequent chemical reactions, and it is non-flammable.

[0010] The catalyst is an antimony-based or organic base catalyst used for polyurethane polymerization / degradation reactions. It is used to catalyze the breaking of urethane bonds in polyurethane molecules, effectively reducing the molecular weight of the polymer and depolymerizing it from a highly crosslinked state.

[0011] The cocatalyst is a urea- or guanidine-containing cocatalyst for polyurethane polymerization / degradation. It can form intermolecular hydrogen bonds with the amine groups in the catalyst to form a synergistic catalytic system, or form intermolecular hydrogen bonds with the ester groups or amide groups in the polyurethane to promote transesterification reaction, reduce the adhesion between polyurethane and the battery cell and structural components, and significantly accelerate the degradation reaction through a multi-action mechanism.

[0012] The decrosslinking agent is a reagent that destroys the three-dimensional crosslinked network of the polymer. It mainly degrades the urethane bonds in the polyurethane network through alcoholysis, ammonolysis, or transesterification reactions, thereby destroying its three-dimensional crosslinked structure.

[0013] The flame-retardant dismantling agent of the polyurethane adhesive also includes 0-10 parts of flame retardant, which is a phosphorus-based flame retardant, further improving the overall fire safety level of the system.

[0014] The technical solution described in this invention constitutes an ordered, synergistic, and functionally complementary disassembly system through the aforementioned components: the solvent first physically swells the polyurethane crosslinked network, opening channels for the entry of the catalyst, co-catalyst, and de-crosslinking agent; the catalyst and co-catalyst synergistically catalyze the debonding and depolymerization of the polyurethane chains, greatly accelerating the debonding and degradation process; the de-crosslinking agent depolymerizes the polyurethane, destroying crosslinking points; and the flame retardant further improves the flame retardant performance of the entire system, ensuring the safety and reliability of the disassembly process. This synergistic effect makes the disassembly process both efficient and safe.

[0015] In one embodiment of the present invention, the solvent includes one or more of 1,1,2-trichloroethane, tetrachloroethane, tetrachloroethylene, carbon tetrachloride, trichloromethane, and dichloromethane.

[0016] In one embodiment of the present invention, the catalyst comprises one or more of antimony trioxide, antimony acetate, antimony glycolate, 4-dimethylaminopyridine, imidazole, 1-methylimidazolium, 1,2,4-triazole, N,N-carbonyldiimidazole, 1,5,7-triazabicyclo[4,4,0]dec-5-ene, 4-pyrrolylpyridine, 1,4-diazabicyclo[2.2.2]octane, and 1,5-diazabicyclo[4.3.0]non-5-ene.

[0017] In one embodiment of the present invention, the co-catalyst includes one or more of urea, thiourea, diphenylguanidine, 1-o-tolyl biguanide, and tetramethylguanidine.

[0018] In one embodiment of the present invention, the decrosslinking agent includes one or more of methanol, ethanol, propanol, ethanolamine, diethanolamine, ethylenediamine, diethylenetriamine, ethyl acetate, butyl acetate, amyl acetate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, dimethyl sulfate, diphenyl sulfate, and diphenyl phosphate.

[0019] In one embodiment of the present invention, the flame retardant includes one or more of triethyl phosphate, triphenyl phosphate, dimethyl methylphosphonate, and diethyl ethylphosphonate.

[0020] The second objective of this invention is to provide a non-destructive disassembly method for a power battery pack, comprising the following steps: immersing the polyurethane structural adhesive bonding components of the power battery pack in the flame-retardant disassembly agent, and then removing them non-destructively after immersion disassembly.

[0021] In one embodiment of the present invention, the volume ratio of the flame-retardant dismantling agent to the polyurethane structural adhesive in the power battery pack is 2:1 to 100:1.

[0022] In one embodiment of the present invention, the disassembly temperature is 20 ℃ to 50 ℃.

[0023] In one embodiment of the present invention, the disassembly process also includes the recovery of a flame-retardant disassembly agent through filtration and distillation.

[0024] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0025] This invention provides a flame-retardant dismantling agent for polyurethane adhesives and a non-destructive dismantling method for power battery packs. Through the synergistic effect of solvents, catalysts, co-catalysts, and de-crosslinking agents, this invention achieves efficient debonding and degradation of polyurethane adhesives under mild conditions. By selecting flame-retardant / non-flammable solvents and compounding flame retardants, the dismantling agent is endowed with excellent flame-retardant properties, effectively solving the fire hazard during power battery dismantling. The flame-retardant high-efficiency dismantling agent provided by this invention is suitable for the debonding and degradation of polyurethane structural adhesives in various power battery packs, and this flame-retardant high-efficiency dismantling agent can be recycled and reused, showing promise for large-scale practical application. Attached Figure Description

[0026] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0027] Figure 1 This is a schematic diagram of a simulated battery pack after polyurethane bonding and curing in Embodiment 1 of the present invention;

[0028] Figure 2 This is a schematic diagram of a simulated battery pack after being immersed in polyurethane adhesive and cured using a flame-retardant dismantling agent in Embodiment 1 of the present invention;

[0029] Figure 3 This is a schematic diagram illustrating the simulated battery pack disassembly effect in Embodiment 1 of the present invention;

[0030] Figure 4 These are actual photographs of the flammability test in Embodiment 1 of the present invention;

[0031] Figure 5 A schematic diagram of the formulation of the polyurethane adhesive flame retardant dismantling agent provided by the present invention;

[0032] Figure 6 This is an actual photograph of the battery pack used in Embodiment 10 of the present invention. The bottom of the battery cell is adhered to the water cooling plate by polyurethane structural adhesive.

[0033] Figure 7 This is an actual photograph of the battery pack disassembly using a flame-retardant high-efficiency disassembly agent in Embodiment 10 of the present invention. The polyurethane structural adhesive at the bottom of the battery pack is immersed in the disassembly liquid.

[0034] Figure 8 This is a diagram showing the effect of disassembling the battery pack in Embodiment 10 of the present invention. The left side shows the disassembled battery cell, and the right side shows the water cooling plate after the battery cell has been disassembled. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.

[0037] To enable the disassembly fluid developed in this invention to be used for disassembling power battery packs, the polyurethane adhesive used in this embodiment is a structural adhesive commonly used in power batteries, namely Debon PU-2020 produced by Yantai Debon Technology Co., Ltd. Two circular aluminum sheets are bonded and cured with polyurethane structural adhesive to simulate the battery pack structure. The simulated battery pack is then immersed in the aforementioned flame-retardant high-efficiency disassembly agent, ensuring the bonding surface formed by the polyurethane adhesive is submerged in the flame-retardant high-efficiency disassembly fluid. After immersion for a certain period, the aluminum sheets can be separated with little or no external force. This process is repeated three times, and the average value is taken. The high-efficiency flame-retardant disassembly agent is then tested in the disassembly of an actual battery pack. The embodiments or accompanying drawings are merely conventional methods. The simulated battery pack only illustrates the effect on the disassembly rate. The disassembly rate of the actual battery pack is affected by factors such as the volume of the polyurethane adhesive in the battery pack, the contact area, and the disassembly temperature, and will be lower than the disassembly rate of the simulated battery pack, manifesting as an increase in disassembly time.

[0038] Example 1

[0039] This embodiment provides a flame-retardant dismantling agent, the specific method of which is as follows:

[0040] By weight, 100 parts of solvent 1,1,2-trichloroethane, 1 part of catalyst N,N-carbonyldiimidazole, 1 part of co-catalyst diphenylguanidine, and 5 parts of decrosslinking agent methanol are mixed to obtain a flame-retardant dismantling agent; a simulated battery pack (such as...) is then used... Figure 1 (As shown) completely submerged in flame-retardant dismantling agent (such as Figure 2 As shown), the volume ratio of flame-retardant dismantling agent to polyurethane adhesive was 50:1. After being kept at a constant temperature of 50 °C for 6 hours, the simulated battery pack was completely dismantled (as shown). Figure 3 (As shown).

[0041] The flammability of the flame-retardant dismantling agent in this embodiment was tested. 5 mL of the agent was placed in a 5 cm diameter combustion dish, and an igniter was used to attempt ignition at a distance of 0.5 cm above the liquid surface for 30 seconds. The agent failed to ignite (e.g., ...). Figure 4 (As shown).

[0042] Example 2

[0043] This embodiment provides a flame-retardant dismantling agent (formulation diagram shown below). Figure 5 (As shown), the specific method is as follows:

[0044] By weight, 100 parts of solvent 1,1,2-trichloroethane, 1 part of catalyst N,N-carbonyldiimidazole, 1 part of co-catalyst diphenylguanidine, 5 parts of de-crosslinking agent methanol and 5 parts of flame retardant triethyl phosphate were mixed to obtain a flame-retardant dismantling agent; the simulated battery pack was completely immersed in the flame-retardant dismantling agent and kept at a constant temperature of 50 °C for 6 hours, after which the simulated battery pack was completely dismantled.

[0045] The flammability of the flame-retardant dismantling agent in this embodiment was tested. 5 mL of the flame-retardant dismantling agent was placed in a combustion dish with a diameter of 5 cm. An igniter was used to attempt to ignite it 0.5 cm above the liquid surface for 30 seconds. It could not be ignited.

[0046] Compared with Example 1, the above results show that the addition of the flame retardant triethyl phosphate has little effect on the debonding and depolymerization of the polyurethane adhesive.

[0047] Example 3

[0048] This embodiment provides a flame-retardant dismantling agent, the specific method of which is as follows:

[0049] By weight, 100 parts of solvent 1,1,2-trichloroethane, 10 parts of catalyst N,N-carbonyldiimidazole, 10 parts of co-catalyst diphenylguanidine, 5 parts of de-crosslinking agent methanol and 5 parts of flame retardant triethyl phosphate were mixed to obtain a flame-retardant dismantling agent; the simulated battery pack was completely immersed in the flame-retardant dismantling agent and kept at a constant temperature of 40 °C for 10 hours to achieve complete dismantling of the simulated battery pack.

[0050] Example 4

[0051] This embodiment provides a flame-retardant dismantling agent, the specific method of which is as follows:

[0052] By weight, 100 parts of solvent 1,1,2-trichloroethane, 5 parts of catalyst 4-dimethylaminopyridine, 10 parts of co-catalyst diphenylguanidine, 20 parts of de-crosslinking agent methanol and 5 parts of flame retardant triethyl phosphate were mixed to obtain a flame-retardant dismantling agent; the simulated battery pack was completely immersed in the flame-retardant dismantling agent and kept at a constant temperature of 50 °C for 8 hours, after which the simulated battery pack was completely dismantled.

[0053] Example 5

[0054] This embodiment provides a flame-retardant dismantling agent, the specific method of which is as follows:

[0055] By weight, 100 parts of solvent 1,1,2-trichloroethane, 1 part of catalyst 1-methylimidazole, 1 part of co-catalyst 1-o-tolylbiguanide, 5 parts of de-crosslinking agent ethanol and 10 parts of flame retardant triethyl phosphate were mixed to obtain a flame-retardant dismantling agent; the simulated battery pack was completely immersed in the flame-retardant dismantling agent and kept at a constant temperature of 50 °C for 8 hours, after which the simulated battery pack was completely dismantled.

[0056] Example 6

[0057] This embodiment provides a flame-retardant dismantling agent, the specific method of which is as follows:

[0058] By weight, 100 parts of solvent 1,1,2-trichloroethane, 1 part of catalyst imidazole, 1 part of co-catalyst diphenylguanidine, 10 parts of de-crosslinking agent dimethyl carbonate and 5 parts of flame retardant triethyl phosphate were mixed to obtain a flame-retardant dismantling agent; the simulated battery pack was completely immersed in the flame-retardant dismantling agent and kept at a constant temperature of 50 °C for 7 hours, after which the simulated battery pack was completely dismantled.

[0059] Example 7

[0060] This embodiment provides a flame-retardant dismantling agent, the specific method of which is as follows:

[0061] By weight, 100 parts of solvent tetrachloroethane, 1 part of N,N-carbonyldiimidazole, 1 part of co-catalyst diphenylguanidine, 5 parts of de-crosslinking agent diphenyl phosphate and 5 parts of flame retardant triethyl phosphate were mixed to obtain a flame-retardant disassembly agent; the simulated battery pack was completely immersed in the flame-retardant disassembly agent and kept at a constant temperature of 50 °C for 10 hours to achieve complete disassembly of the simulated battery pack.

[0062] Example 8

[0063] This embodiment provides a flame-retardant dismantling agent, the specific method of which is as follows:

[0064] By weight, 100 parts of solvent dichloromethane, 5 parts of 4-dimethylaminopyridine, 10 parts of co-catalyst diphenylguanidine, 5 parts of de-crosslinking agent methanol and 5 parts of flame retardant triphenyl phosphate were mixed to obtain a flame-retardant dismantling agent; the simulated battery pack was completely immersed in the flame-retardant dismantling agent and kept at a constant temperature of 30 °C for 6 hours to achieve complete dismantling of the simulated battery pack.

[0065] Example 9

[0066] This embodiment provides a flame-retardant dismantling agent, the specific method of which is as follows:

[0067] By weight, 100 parts of solvent tetrachloroethylene, 1 part of 4-dimethylaminopyridine, 11 parts of co-catalyst diphenylguanidine, 15 parts of de-crosslinking agent diphenyl carbonate and 5 parts of flame retardant triphenyl phosphate were mixed to obtain a flame-retardant dismantling agent; the simulated battery pack was completely immersed in the flame-retardant dismantling agent and kept at a constant temperature of 50 °C for 8 hours to achieve complete dismantling of the simulated battery pack.

[0068] Example 10

[0069] This embodiment provides a method for non-destructive disassembly of a battery pack using a flame-retardant disassembly agent. The battery pack used is as follows: Figure 6 As shown, the specific method is as follows:

[0070] A flame-retardant dismantling agent was prepared using the method described in Example 2. The battery cell and water-cooled plate, bonded with polyurethane adhesive, were placed in a dismantling solution, with the polyurethane bonding surfaces completely submerged in the dismantling agent. Figure 7 As shown, after maintaining a constant temperature of 50°C for 20 hours, the battery pack was completely disassembled. The battery cells can then be directly removed, thus separating them from the water-cooling plate, as shown below. Figure 8 As shown.

[0071] Comparative Example 1

[0072] This comparative example provides a flame-retardant dismantling agent without a de-crosslinking agent, similar to Example 1, except that methanol, the de-crosslinking agent, is not added; details are as follows:

[0073] By weight, 100 parts of solvent 1,1,2-trichloroethane, 1 part of catalyst N,N-carbonyldiimidazole and 1 part of co-catalyst diphenylguanidine were mixed to obtain a disassembly agent; the simulated battery pack was completely immersed in the disassembly agent and kept at a constant temperature of 50 °C for 10 hours to achieve complete disassembly of the simulated battery pack.

[0074] Compared with Example 1, the above results show that the decrosslinking agent helps to de-adhere and depolymerize the polyurethane adhesive. The lack of the decrosslinking agent will significantly prolong the disassembly time and make it impossible to achieve efficient disassembly.

[0075] Comparative Example 2

[0076] This comparative example provides a flame-retardant dismantling agent without a co-catalyst, similar to Example 1, except that it does not contain the co-catalyst diphenylguanidine; details are as follows:

[0077] By weight, 100 parts of solvent 1,1,2-trichloroethane, 1 part of catalyst N,N-carbonyldiimidazole, and 5 parts of decrosslinking agent methanol were mixed to obtain a disassembly agent; the simulated battery pack was completely immersed in the disassembly agent and kept at a constant temperature of 50 °C for 12 hours to achieve complete disassembly of the simulated battery pack.

[0078] Compared with Example 1, the above results show that the co-catalyst helps the polyurethane adhesive to de-adhede and depolymerize. The lack of the co-catalyst will significantly prolong the disassembly time and make it impossible to achieve efficient disassembly.

[0079] Comparative Example 3

[0080] This comparative example provides a catalyst-free flame-retardant dismantling agent, similar to Example 1, except that it does not contain the catalyst N,N-carbonyldiimidazole; details are as follows:

[0081] By weight, 100 parts of solvent 1,1,2-trichloroethane, 1 part of co-catalyst diphenylguanidine, and 5 parts of de-crosslinking agent methanol were mixed to obtain a disassembly agent; the simulated battery pack was completely immersed in the disassembly agent and kept at a constant temperature of 50 °C for 13 hours to achieve complete disassembly of the simulated battery pack.

[0082] Compared with Example 1, the above results show that the catalyst helps the polyurethane adhesive to depolymerize and de-adhede. The lack of catalyst will significantly prolong the disassembly time and make it impossible to achieve efficient disassembly.

[0083] Comparative Example 4

[0084] This comparative example provides a flame-retardant dismantling agent without catalyst and co-catalyst, similar to Example 1, except that it does not contain the catalyst N,N-carbonyldiimidazole and the co-catalyst diphenylguanidine; details are as follows:

[0085] By weight, 100 parts of solvent 1,1,2-trichloroethane and 5 parts of de-crosslinking agent methanol were mixed to obtain a disassembly agent; the simulated battery pack was completely immersed in the disassembly agent and kept at a constant temperature of 50 °C for 20 hours to achieve complete disassembly of the simulated battery pack.

[0086] Compared with Example 1, the above results show that the catalyst and co-catalyst help the polyurethane adhesive to depolymerize and depolymerize.

[0087] Comparative Example 5

[0088] This comparative example provides a flame-retardant dismantling agent that does not contain a catalyst, co-catalyst, or de-crosslinking agent, similar to Example 1, except that it does not contain the catalyst N,N-carbonyldiimidazole, the co-catalyst diphenylguanidine, or the de-crosslinking agent methanol; details are as follows:

[0089] The simulated battery pack was completely immersed in the solvent 1,1,2-trichloroethane and kept at a constant temperature of 50 °C for 24 hours. After that, the simulated battery pack could not be completely disassembled.

[0090] Compared with Example 1, the above results show that the catalyst, co-catalyst and de-crosslinking agent help to de-adhere and depolymerize the polyurethane adhesive.

[0091] Comparative Example 6

[0092] This comparative example provides a flame-retardant dismantling agent, similar to Example 2, except that the solvent 1,1,2-trichloroethane is replaced with trichloroethanol; specifically as follows:

[0093] By weight, 100 parts of solvent trichloroethanol, 1 part of catalyst N,N-carbonyldiimidazole, 1 part of co-catalyst diphenylguanidine, 5 parts of de-crosslinking agent methanol and 5 parts of flame retardant triethyl phosphate were mixed to obtain a disassembly agent; the simulated battery pack was completely immersed in the disassembly agent and kept at a constant temperature of 50 °C for 24 hours to achieve complete disassembly of the simulated battery pack.

[0094] Compared with Example 2, the above results show that the choice of solvent has a significant impact on the debonding and depolymerization of polyurethane adhesive.

[0095] Comparative Example 7

[0096] This comparative example provides a flame-retardant dismantling agent, similar to Example 2, except that the solvent 1,1,2-trichloroethane is replaced with HFE7300 (a fluorinated liquid manufactured by 3M Novec, USA); details are as follows:

[0097] By weight, 100 parts of solvent HFE7300, 1 part of catalyst N,N-carbonyldiimidazole, 1 part of co-catalyst diphenylguanidine, 5 parts of de-crosslinking agent methanol and 5 parts of flame retardant triethyl phosphate were mixed to obtain a disassembly agent; the simulated battery pack was completely immersed in the disassembly agent and kept at a constant temperature of 50 °C for 30 hours. After that, the simulated battery pack could not be completely disassembled.

[0098] Comparative Example 8

[0099] This comparative example provides a flame-retardant dismantling agent, similar to Example 2, except that the solvent 1,1,2-trichloroethane is replaced with chlorodiethylene glycol; specifically as follows:

[0100] By weight, 100 parts of solvent dichlorodiethylene glycol, 1 part of catalyst N,N-carbonyldiimidazole, 1 part of co-catalyst diphenylguanidine, 5 parts of de-crosslinking agent methanol and 5 parts of flame retardant triethyl phosphate were mixed to obtain a disassembly agent; the simulated battery pack was completely immersed in the disassembly agent and kept at a constant temperature of 50 °C for 30 hours, after which the simulated battery pack could not be completely disassembled.

[0101] Comparative Example 9

[0102] This comparative example provides a polyurethane disintegrating agent, and the specific method is as follows:

[0103] The solvent N,N-dimethylformamide and the catalyst 1,5,7-triazabicyclo[4,4,0]dec-5-ene were mixed at a mass ratio of 100:1 to obtain the disassembly agent; the simulated battery pack was completely immersed in the disassembly agent and kept at a constant temperature of 50 °C for 24 hours, after which the simulated battery pack was completely disassembled.

[0104] The solvent N,N-dimethylformamide in this comparative example is a flammable liquid. Under the constant temperature of 50 °C during the disassembly of the power battery, it is easy to volatilize and form flammable vapors. If it comes into contact with a source of ignition, it may cause a fire or even an explosion, posing a safety hazard. Moreover, its disassembly time is as long as 24 hours, which is 4 times that of Example 1.

[0105] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A flame-retardant disassembling agent for polyurethane glue, characterized by comprising: By weight, the flame-retardant dismantling agent comprises 100 parts solvent, 0.1-15 parts catalyst, 0.1-15 parts co-catalyst, and 0.1-30 parts de-crosslinking agent; The solvent is a halogenated hydrocarbon solvent that has an affinity for polyurethane; The catalyst is an antimony-based or organic base catalyst used for polyurethane polymerization / degradation; The cocatalyst is a urea- or guanidine-containing cocatalyst used for polyurethane polymerization / degradation. The decrosslinking agent is a reagent that disrupts the three-dimensional crosslinked network of the polymer.

2. The flame-retardant disassembling agent according to claim 1, characterized by, The solvent includes one or more of 1,1,2-trichloroethane, tetrachloroethane, tetrachloroethylene, carbon tetrachloride, chloroform, and dichloromethane.

3. The flame-retardant dismantling agent according to claim 1, characterized in that, The catalyst comprises one or more of the following: antimony trioxide, antimony acetate, antimony glycol, 4-dimethylaminopyridine, imidazole, 1-methylimidazolium, 1,2,4-triazole, N,N-carbonyldiimidazole, 1,5,7-triazabicyclo[4,4,0]dec-5-ene, 4-pyrrolylpyridine, 1,4-diazabicyclo[2.2.2]octane, and 1,5-diazabicyclo[4.3.0]non-5-ene.

4. The flame-retardant dismantling agent according to claim 1, characterized in that, The co-catalyst includes one or more of urea, thiourea, diphenylguanidine, 1-o-tolyl biguanide, and tetramethylguanidine.

5. The flame-retardant dismantling agent according to claim 1, characterized in that, The decrosslinking agent includes one or more of methanol, ethanol, propanol, ethanolamine, diethanolamine, ethylenediamine, diethylenetriamine, ethyl acetate, butyl acetate, amyl acetate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, dimethyl sulfate, diphenyl sulfate, and diphenyl phosphate.

6. The flame-retardant dismantling agent according to claim 1, characterized in that, The flame-retardant dismantling agent further includes 0-10 parts of flame retardant; the flame retardant includes one or more of triethyl phosphate, triphenyl phosphate, dimethyl methylphosphonate and diethyl ethylphosphonate.

7. A non-destructive disassembly method for a power battery pack, characterized in that, Includes the following steps: The polyurethane structural adhesive bonding components of the power battery pack are immersed in the flame-retardant dismantling agent as described in any one of claims 1-6, and after soaking and dismantling, they are removed without damage.

8. The non-destructive disassembly method according to claim 7, characterized in that, The volume ratio of the flame-retardant dismantling agent to the polyurethane structural adhesive in the power battery pack is 2:1 to 100:

1.

9. The non-destructive disassembly method according to claim 7, characterized in that, The disassembly temperature is 20 ℃ to 50 ℃.

10. The non-destructive disassembly method according to claim 7, characterized in that, After dismantling, flame-retardant dismantling agents are recovered through filtration and distillation.

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