Lithium battery, high-temperature-resistant aluminum-plastic film and preparation method thereof

Abstract

The invention provides a lithium battery, a high-temperature-resistant aluminum plastic film and a preparation method of the high-temperature-resistant aluminum plastic film. The preparation method of the high-temperature-resistant aluminum plastic film comprises the following steps: obtaining the aluminum foil layer, the nylon layer and the CPP layer. And carrying out surface passivation treatment on the aluminum foil layer. And preparing the novel polyurethane adhesive. Carrying out first compounding treatment on the aluminum foil layer subjected to surface passivation treatment and a nylon layer by adopting the novel polyurethane binder to obtain a first composite film layer; and carrying out first curing treatment on the first composite film layer. And preparing the modified polyolefin binder. And performing second compounding treatment on the first composite film layer subjected to the first curing treatment and the CPP layer by adopting the modified polyolefin binder to obtain a second composite film layer. And carrying out second curing treatment on the second composite film layer to obtain the high-temperature-resistant aluminum-plastic film.

Description

Technical Field

[0001] The present disclosure relates to the field of lithium batteries, and in particular to a lithium battery, a high temperature resistant aluminum-plastic film and a preparation method thereof. Background Art

[0002] In recent years, soft-package lithium-ion batteries have become a widely used rechargeable battery. The main users include 3C electronic products, power batteries, and energy storage. The aluminum-plastic film of soft-package lithium-ion batteries is mainly composed of nylon, aluminum foil layer, CPP layer and glue layer. The aluminum-plastic film is used as the outer packaging material of the battery. In recent years, the performance requirements of the aluminum-plastic film have become more and more stringent for different application fields, especially in power and energy storage. The temperature resistance of the aluminum-plastic film is mainly affected by the temperature resistance of the CPP layer and the nylon layer of the aluminum-plastic film. Specifically, the high temperature resistance of the adhesive between the CPP layer and the aluminum foil layer is poor, and the high temperature resistance of the adhesive between the nylon layer and the aluminum foil layer is poor. When the aluminum-plastic film is molded and packaged, the adhesive is easily ineffective at high temperature, resulting in delamination, blistering, and poor heat sealing of the CPP layer, which leads to the risk of leakage of the battery, which seriously affects the use of the battery, wastes materials and causes losses.

[0003] Therefore, how to improve the temperature resistance of aluminum-plastic film is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a lithium battery, a high temperature resistant aluminum-plastic film and a preparation method thereof that can improve the temperature resistance of the aluminum-plastic film.

[0005] The purpose of this disclosure is achieved through the following technical solutions:

[0006] A method for preparing a high temperature resistant aluminum-plastic film comprises the following steps:

[0007] Obtaining aluminum foil layer, nylon layer and CPP layer;

[0008] Performing surface passivation treatment on the aluminum foil layer;

[0009] Preparation of new polyurethane adhesive;

[0010] The aluminum foil layer and the nylon layer having the surface passivated are subjected to a first composite treatment using the novel polyurethane adhesive to obtain a first composite film layer;

[0011] performing a first aging treatment on the first composite film layer;

[0012] preparing a modified polyolefin adhesive;

[0013] Using the modified polyolefin adhesive, the first composite film layer after the first aging treatment and the CPP layer are subjected to a second composite treatment to obtain a second composite film layer;

[0014] The second composite film layer is subjected to a second aging treatment to obtain a high temperature resistant aluminum-plastic film.

[0015] In one embodiment, the novel polyurethane adhesive comprises the following components in parts by weight:

[0016]

[0017] In one embodiment, the specific steps of preparing the novel polyurethane adhesive are:

[0018] The amine catalyst and the ethyl acetate are mixed and added into the reaction kettle to perform a first stirring operation;

[0019] Adding the polyhydroxy compound into the reactor to perform a second stirring operation;

[0020] The polyisocyanate compound and the ethyl acetate are mixed and added into the reaction kettle to perform a third stirring operation to obtain the novel polyurethane adhesive.

[0021] In one embodiment, the specific operation steps of using the novel polyurethane adhesive to perform a first composite treatment on the surface passivated aluminum foil layer and the nylon layer are as follows:

[0022] Applying the novel polyurethane adhesive on the nylon layer;

[0023] Aligning and laminating one side of the nylon layer with the novel polyurethane adhesive with one side of the aluminum foil layer to form a first composite film layer;

[0024] The first composite film layer is subjected to a first rolling operation by a rolling press.

[0025] In one embodiment, the modified polyolefin binder comprises the following components in parts by weight:

[0026]

[0027] In one embodiment, the specific steps of preparing the modified polyolefin binder are:

[0028] Adding the modified chloropropylene compound into the reactor to perform a fourth stirring operation;

[0029] The diisocyanate compound and the methylcyclohexane are mixed and added into the reactor to perform a fifth stirring operation;

[0030] The epoxy resin compound and the methylcyclohexane are mixed and added into the reaction kettle to perform a sixth stirring operation to obtain the modified polyolefin adhesive modified polyolefin glue.

[0031] In one embodiment, the specific operation steps of using the modified polyolefin adhesive to perform a second composite treatment on the first composite film layer after the first aging treatment and the CPP layer are:

[0032] coating the modified polyolefin adhesive on the CPP layer;

[0033] Aligning and laminating one side of the CPP layer with the modified polyolefin adhesive with the other side of the aluminum foil layer of the first composite film layer to form a second composite film layer;

[0034] The second composite film layer is subjected to a second rolling operation by the rolling machine.

[0035] In one embodiment, after the step of performing a second aging treatment on the second composite film layer, the method for preparing the high temperature resistant aluminum-plastic film further comprises the following steps:

[0036] The second composite film layer after the second aging treatment is cut to obtain a high temperature resistant aluminum-plastic film.

[0037] A high temperature resistant aluminum-plastic film is prepared by using the method for preparing the high temperature resistant aluminum-plastic film described in any one of the above embodiments.

[0038] A lithium battery comprises the high temperature resistant aluminum-plastic film described in the above embodiment.

[0039] Compared with the prior art, the present invention has at least the following advantages:

[0040] The passivated aluminum foil layer and the nylon layer are subjected to a first composite treatment by using a new polyurethane adhesive to ensure that the new polyurethane adhesive can cover the connecting surface between the aluminum foil layer and the nylon layer. The first composite film layer is subjected to a first aging treatment to allow the components in the new polyurethane adhesive to fully react, thereby forming an adhesive layer with strong bonding force and good temperature resistance, thereby effectively improving the bonding force between the aluminum foil layer and the nylon layer. The first composite film layer and the CPP layer are subjected to a second composite treatment by using a modified polyolefin adhesive to ensure that the modified polyolefin glue can cover the connecting surface between the passivated aluminum foil layer and the CPP layer, and the second composite film layer is subjected to a second aging treatment to allow the components in the modified polyolefin adhesive to fully react, thereby forming an adhesive layer with strong bonding force and good heat resistance, so that the bonding force between the aluminum foil layer and the CPP layer is effectively improved, so that the high-temperature resistant aluminum-plastic film is not prone to delamination, blistering, and poor heat sealing of the CPP layer when used in the lithium battery production process, thereby ensuring that the aluminum-plastic film has good protection performance and avoids battery leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 The present invention is a flow chart of a method for preparing a high temperature resistant aluminum-plastic film. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thoroughly and comprehensively understood.

[0044] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0046] The present disclosure provides a method for preparing a high temperature resistant aluminum-plastic film, comprising the following steps: obtaining an aluminum foil layer, a nylon layer and a CPP layer. Performing a surface passivation treatment on the aluminum foil layer. Preparing a novel polyurethane adhesive. Using the novel polyurethane adhesive, performing a first composite treatment on the aluminum foil layer and the nylon layer subjected to the surface passivation treatment to obtain a first composite film layer. Performing a first aging treatment on the first composite film layer. Preparing a modified polyolefin adhesive. Using the modified polyolefin adhesive, performing a second composite treatment on the first composite film layer and the CPP layer after the first aging treatment to obtain a second composite film layer. Performing a second aging treatment on the second composite film layer to obtain a high temperature resistant aluminum-plastic film.

[0047] The preparation method of the above-mentioned high-temperature resistant aluminum-plastic film is to perform a first composite treatment on the passivated aluminum foil layer and the nylon layer by using a new polyurethane adhesive to ensure that the new polyurethane adhesive can cover the connecting surface between the aluminum foil layer and the nylon layer, and then perform a first aging treatment on the first composite film layer so that the components in the new polyurethane adhesive are fully reacted to form an adhesive layer with strong bonding force and good temperature resistance, so that the bonding force between the aluminum foil layer and the nylon layer is effectively improved. The first composite film layer and the CPP layer are subjected to a second composite treatment by using a modified polyolefin adhesive to ensure that the modified polyolefin glue can cover the connecting surface between the passivated aluminum foil layer and the CPP layer, and the second composite film layer is subjected to a second aging treatment to allow the components in the modified polyolefin adhesive to fully react, thereby forming an adhesive layer with strong bonding force and good heat resistance, so that the bonding force between the aluminum foil layer and the CPP layer is effectively improved, so that the high-temperature resistant aluminum-plastic film is not prone to delamination, blistering, and poor heat sealing of the CPP layer when used in the lithium battery production process, thereby ensuring that the aluminum-plastic film has good protection performance and avoids battery leakage.

[0048] Please refer to the following, in order to better understand the preparation method of the high temperature resistant aluminum-plastic film disclosed in the present invention, the preparation method of the high temperature resistant aluminum-plastic film is further explained:

[0049] A method for preparing a high temperature resistant aluminum-plastic film according to one embodiment comprises the following steps:

[0050] S100, obtaining an aluminum foil layer, a nylon layer and a CPP layer.

[0051] In this example, the aluminum foil layer, nylon layer and CPP layer are cut to the required length for batch production according to production needs, so as to realize the continuous production of batch aluminum-plastic film.

[0052] S200, performing surface passivation treatment on the aluminum foil layer.

[0053] In this embodiment, a trivalent chromium passivator containing acrylate is used to passivate the surface of the aluminum foil, so that a corrosion-resistant passivation layer is formed on the surface of the aluminum foil layer, so that the corrosion resistance of the aluminum foil layer of the aluminum-plastic film is effectively improved, thereby effectively improving the corrosion resistance of the aluminum-plastic film.

[0054] Furthermore, in one embodiment, the flash point temperature of the passivation reaction of the surface passivation treatment is 180°C; the coating amount of the trivalent chromium passivator containing acrylate is 0.1 g / m 2 ~0.3g / m 2 It is understandable that the temperature needs to be controlled below 180°C during the surface passivation process to avoid safety accidents. At the same time, under this coating amount, a corrosion-resistant passivation layer can be formed on the surface of the aluminum foil layer, which greatly improves the corrosion resistance of the aluminum-plastic film.

[0055] S300, preparation of new polyurethane adhesive.

[0056] In this embodiment, a new type of polyurethane adhesive is prepared, and the new type of polyurethane adhesive has strong bonding properties and good high temperature resistance, so that the cured bonding layer has strong bonding force and still maintains a relatively stable bonding strength at high temperatures, thereby improving the temperature resistance of the aluminum-plastic film.

[0057] S400, using the novel polyurethane adhesive to perform a first composite treatment on the surface passivated aluminum foil layer and the nylon layer to obtain a first composite film layer.

[0058] In this embodiment, the passivated aluminum foil layer and the nylon layer are compounded together by a new polyurethane adhesive, ensuring that the new polyurethane adhesive covers the connecting surface between the aluminum foil layer and the nylon layer, thereby ensuring a strong bonding force between the aluminum foil layer and the nylon layer.

[0059] S500, performing a first aging treatment on the first composite film layer.

[0060] In this embodiment, by subjecting the first composite film layer to a aging treatment, the various components in the novel polyurethane adhesive are fully reacted to form an adhesive layer having a strong adhesive force and good heat resistance, thereby improving the adhesive force between the aluminum foil layer and the nylon layer, thereby effectively improving the heat resistance of the aluminum-plastic film.

[0061] Furthermore, in one embodiment, the temperature of the first aging treatment is 60°C to 85°C; the time of the first aging treatment is 3 days to 7 days. It can be understood that under the first aging treatment conditions, the components in the novel polyurethane adhesive fully react and solidify to form a novel polyurethane adhesive layer with good temperature resistance and strong bonding force, thereby effectively enhancing the bonding force between the aluminum foil layer and the nylon layer, and improving the high temperature resistance of the aluminum-plastic film.

[0062] S600, preparing a modified polyolefin adhesive.

[0063] In this embodiment, a modified polyolefin adhesive is prepared, and the modified polyolefin adhesive has strong bonding properties and good high temperature resistance, so that the adhesive layer after curing has strong bonding force and still maintains a relatively stable bonding strength at high temperatures, thereby improving the temperature resistance of the aluminum-plastic film.

[0064] S700, using the modified polyolefin adhesive to perform a second composite treatment on the first composite film layer after the first aging treatment and the CPP layer to obtain a second composite film layer.

[0065] In this embodiment, the passivated aluminum foil layer and the CPP layer are compounded together by a modified polyolefin adhesive, ensuring that the modified polyolefin adhesive covers the connecting surface between the aluminum foil layer and the CPP layer, thereby ensuring a strong bonding force between the aluminum foil layer and the CPP layer.

[0066] S800, performing a second aging treatment on the second composite film layer to obtain a high temperature resistant aluminum-plastic film.

[0067] In this embodiment, by performing a aging treatment on the second composite film layer, the components in the modified polyolefin adhesive are fully reacted to form a modified polyolefin adhesive layer with strong bonding force and good temperature resistance, thereby improving the bonding force between the aluminum foil layer and the CPP layer, thereby effectively improving the temperature resistance of the aluminum-plastic film, avoiding the situation where the heat sealing effect of the CPP layer is poor, and then effectively improving the sealing stability of the aluminum-plastic film.

[0068] Furthermore, in one embodiment, the temperature of the second aging treatment is 55°C to 70°C; and the time of the second aging treatment is 5 days to 7 days. It can be understood that under the second aging treatment conditions, the components in the modified polyolefin adhesive fully react and solidify to form a modified polyolefin adhesive layer with good temperature resistance and strong bonding force, thereby effectively enhancing the bonding force between the aluminum foil layer and the CPP layer, and improving the high temperature resistance of the aluminum-plastic film, further avoiding the situation where the heat sealing effect of the CPP layer is poor, so that the aluminum-plastic film has good sealing stability when applied to lithium batteries.

[0069] In one embodiment, the novel polyurethane adhesive comprises the following components in parts by weight:

[0070]

[0071] It should be noted that the polyhydroxy compound containing a hydroxyl end and the polyisocyanate compound generate a polyester-type branched three-dimensional cross-linked structure polymer under the catalysis of an amine catalyst. Specifically, when the isocyanate in the polyisocyanate compound contacts the active hydrogen in the polyhydroxy compound, an addition reaction occurs to generate a carbamate structure, so that the polyhydroxy compound and the polyisocyanate compound molecules are combined with each other, the molecular weight is multiplied, and a three-dimensional cross-linked structure with branches is generated, so that the new polyurethane adhesive has the characteristics of high and low temperature resistance, medium corrosion resistance, high bonding strength, etc., and the isocyanate group (-NCO, i.e. -N=C=O) or other active reactive groups in the polyisocyanate compound In addition to reacting with the active hydrogen in the polyol compound, the modified polyester polyurethane adhesive layer can also react with the active hydrogen in the surface material of the bonded material to generate chemical bonds, so that the adhesive molecules can simultaneously bridge the two bonded materials to generate stronger bonding force. The new polyurethane adhesive layer formed after full cross-linking and curing has a very high cohesive force. The new polyurethane adhesive layer is not only strong and soft, but also has good heat resistance and resistance to medium erosion. That is to say, the modified polyester polyurethane adhesive layer plays a bridging role between the aluminum foil layer and the nylon layer, improves the bonding force between the aluminum foil layer and the nylon layer, and can also make the aluminum-plastic film have good heat resistance and corrosion resistance.

[0072] In one embodiment, the specific steps of preparing the novel polyurethane adhesive are:

[0073] The amine catalyst and the ethyl acetate are mixed and added into the reaction kettle to perform a first stirring operation;

[0074] Adding the polyhydroxy compound into the reactor to perform a second stirring operation;

[0075] The polyisocyanate compound and the ethyl acetate are mixed and added into the reaction kettle to perform a third stirring operation to obtain the novel polyurethane adhesive.

[0076] It should be noted that, since both the amine catalyst and the polyisocyanate compound have a catalytic effect, when mixed with the polyhydroxy compound, there will be a situation where the reaction is uneven due to the excessive concentration of the polyisocyanate compound added instantly or the amine catalyst concentration is too high, forming a local accelerated curing reaction in the system, so that particles are formed in the novel polyurethane binder, which will affect the bonding strength and flatness of the novel polyurethane bonding layer when the aluminum-plastic film is made into a film. Therefore, in the present embodiment, the amine catalyst needs to be diluted 2 to 3 times with ethyl acetate before adding, and the amine catalyst and ethyl acetate are mixed and added to the reactor for the first stirring operation, and then the polyhydroxy compound is added to the reactor for the second stirring operation to avoid the situation of local curing. Similarly, the polyisocyanate compound needs to be diluted 2 to 3 times with ethyl acetate before adding, and the polyisocyanate compound and ethyl acetate are mixed and added to the reactor for the third stirring operation, so that the reaction in the system is more uniform, and the situation of local curing is avoided, so that each component in the system is evenly dispersed while fully reacting and crosslinking, and the formation of particles is avoided, and the bonding strength and flatness of the novel polyurethane bonding layer are improved.

[0077] It should be additionally explained that the first stirring operation, the second stirring operation and the third stirring operation start stirring at the same time when the materials are added, that is, stirring is performed while adding.

[0078] In one embodiment, the stirring speed of the first stirring operation is 200 r / min to 300 r / min, and the duration of the first stirring operation is 5 min.

[0079] In one embodiment, the stirring speed of the second stirring operation is 200 r / min to 300 r / min, and the duration of the second stirring operation is 15 min.

[0080] In one embodiment, the stirring speed of the third stirring operation is 300 r / min to 400 r / min, and the duration of the third stirring operation is 15 min.

[0081] In one embodiment, the polyol compound is a combination of one or more of ethylene glycol, propylene glycol, glycerol, 1,2,3-propanetriol, glyceryl stearate and polyol polyester.

[0082] In one embodiment, the polyisocyanate compound is a combination of one or more of hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, trimethylhexane diisocyanate and tetramethylphenylenediisocyanate.

[0083] In one embodiment, the amine catalyst is a combination of one or more of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine and N,N-dimethylbenzylamine.

[0084] In one embodiment, the specific operation steps of using the novel polyurethane adhesive to perform a first composite treatment on the surface passivated aluminum foil layer and the nylon layer are as follows:

[0085] Applying the novel polyurethane adhesive on the nylon layer;

[0086] Aligning and laminating one side of the nylon layer with the novel polyurethane adhesive with one side of the aluminum foil layer to form a first composite film layer;

[0087] The first composite film layer is subjected to a first rolling operation by a rolling press.

[0088] It should be noted that the new polyurethane adhesive is first evenly coated on the aluminum foil layer, and then one side of the nylon layer is aligned with the side of the aluminum foil layer coated with the new polyurethane adhesive and bonded together. The first composite film layer is then subjected to heat pressing treatment using a roller press to evenly disperse the new polyurethane adhesive on the connecting surface between the nylon layer and the aluminum foil layer. The new polyurethane adhesive fully reacts and cross-links with the nylon layer and the aluminum foil layer under heat pressing, thereby increasing the bonding strength between the nylon layer and the aluminum foil layer.

[0089] In one embodiment, the temperature of the first rolling operation is 85°C to 100°C; the rolling pressure of the first rolling operation is 0.4MPa to 0.5MPa. It can be understood that under this condition, the new polyurethane adhesive can be evenly dispersed on the connecting surface between the nylon layer and the aluminum foil layer, thereby effectively improving the bonding strength between the nylon layer and the aluminum foil layer.

[0090] In one embodiment, the modified polyolefin binder comprises the following components in parts by weight:

[0091]

[0092]

[0093] It should be noted that the modified polyolefin adhesive forms a diisocyanate film layer after reaction, and the diisocyanate film layer can react with the maleic anhydride of the CPP bonding layer to generate an imide ring with high heat resistance. The diisocyanate can also react with the dianhydride in the CPP bonding layer to produce a polyimide with high heat resistance, which can effectively improve the heat resistance of the modified polyolefin adhesive layer. The diisocyanate film layer reacts with the acrylate of the bright passivation layer to form a modified polyolefin adhesive layer with strong bonding force and strong resistance to electrolyte corrosion, which can effectively improve the temperature resistance, bonding strength and corrosion resistance of the aluminum-plastic film.

[0094] In one embodiment, the specific steps of preparing the modified polyolefin binder are:

[0095] Adding the modified allyl chloride compound into the reaction kettle to perform a fourth stirring operation;

[0096] adding the diisocyanate compound and the methylcyclohexane into the reaction kettle to perform a fifth stirring operation;

[0097] The epoxy resin compound and the methylcyclohexane are added into the reaction kettle to perform a sixth stirring operation to obtain the modified polyolefin adhesive.

[0098] It should be noted that, since both the diisocyanate compound and the epoxy resin compound have a catalytic effect, when mixed with the modified chloropropylene compound, there will be a situation where the reaction is uneven due to the diisocyanate compound concentration added instantly being too high or the epoxy resin compound concentration being too high, and a local accelerated curing reaction is formed in the system, so that particles are formed in the modified polyolefin adhesive, which will affect the bonding strength and flatness of the modified polyolefin adhesive layer when the aluminum-plastic film is made. Therefore, in this embodiment, the polyvalent hydroxy compound is first added to the reactor for the fourth stirring operation, and the diisocyanate compound needs to be diluted 2 to 3 times with methylcyclohexane before being added, and the diisocyanate compound and methylcyclohexane are mixed and added to the reactor for the fifth stirring operation to avoid the situation of local curing. Similarly, the epoxy resin compound needs to be diluted 2 to 3 times with methylcyclohexane before being added. After the epoxy resin compound and methylcyclohexane are mixed, they are added to the reactor for the sixth stirring operation to make the reaction in the system more uniform and avoid local curing. This allows the components in the system to fully react and cross-link while being evenly dispersed, avoiding the formation of particulate matter and improving the bonding strength and flatness of the modified polyolefin bonding layer.

[0099] In one embodiment, the stirring speed of the fourth stirring operation is 200 r / min to 300 r / min, and the duration of the fourth stirring operation is 5 min.

[0100] In one embodiment, the stirring speed of the fifth stirring operation is 200 r / min to 300 r / min, and the duration of the second stirring operation is 15 min.

[0101] In one embodiment, the stirring speed of the sixth stirring operation is 200 r / min to 300 r / min, and the duration of the first stirring operation is 25 min.

[0102] In one embodiment, the diisocyanate compound is a combination of one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate.

[0103] In one embodiment, the specific operation steps of using the modified polyolefin adhesive to perform a second composite treatment on the first composite film layer after the first aging treatment and the CPP layer are:

[0104] coating the modified polyolefin adhesive on the other side of the aluminum foil layer of the first composite film layer;

[0105] Aligning and laminating the side of the aluminum foil layer of the first composite film layer with the modified polyolefin adhesive with the CPP layer to form a second composite film layer;

[0106] The second composite film layer is subjected to a second rolling operation by the rolling machine.

[0107] It should be noted that the modified polyolefin adhesive is first evenly coated on the other side of the aluminum foil layer of the first composite film layer, and then the CPP layer and the other side of the aluminum foil layer of the first composite film layer coated with the modified polyolefin adhesive are aligned and bonded, and then the second composite film layer is subjected to heat pressing treatment by a roller press, so that the modified polyolefin adhesive is evenly dispersed on the connecting surface between the CPP layer and the aluminum foil layer, and the new polyurethane adhesive fully reacts and cross-links with the nylon layer and the aluminum foil layer under hot pressing, thereby increasing the bonding strength between the nylon layer and the aluminum foil layer.

[0108] In one embodiment, the temperature of the second rolling operation is 95°C to 105°C; the rolling pressure of the second rolling operation is 0.45MPa to 0.5MPa. It can be understood that under this condition, the modified polyolefin adhesive can be evenly dispersed on the connecting surface between the CPP layer and the aluminum foil layer, thereby effectively improving the bonding strength between the CPP layer and the aluminum foil layer.

[0109] In one embodiment, after the step of performing a second aging treatment on the second composite film layer, the method for preparing the high temperature resistant aluminum-plastic film further comprises the following steps:

[0110] The second composite film layer after the second aging treatment is cut to obtain a high temperature resistant aluminum-plastic film.

[0111] It can be understood that by cutting the second composite film layer, a plurality of high temperature resistant aluminum-plastic films can be obtained, thereby realizing mass production of high temperature resistant aluminum-plastic films.

[0112] The present disclosure also provides a high temperature resistant aluminum-plastic film, which is prepared by the method for preparing the high temperature resistant aluminum-plastic film described in any of the above embodiments.

[0113] In this example, the passivated aluminum foil layer and the nylon layer are subjected to a first composite treatment using a new polyurethane adhesive to ensure that the new polyurethane adhesive can cover the connecting surface between the aluminum foil layer and the nylon layer. The first composite film layer is subjected to a first aging treatment to allow the components in the new polyurethane adhesive to fully react, thereby forming an adhesive layer with strong bonding force and good temperature resistance, thereby effectively improving the bonding force between the aluminum foil layer and the nylon layer. The first composite film layer and the CPP layer are subjected to a second composite treatment by using a modified polyolefin adhesive to ensure that the modified polyolefin glue can cover the connecting surface between the passivated aluminum foil layer and the CPP layer, and the second composite film layer is subjected to a second aging treatment to allow the components in the modified polyolefin adhesive to fully react, thereby forming an adhesive layer with strong bonding force and good heat resistance, so that the bonding force between the aluminum foil layer and the CPP layer is effectively improved, so that the high-temperature resistant aluminum-plastic film is not prone to delamination, blistering, and poor heat sealing of the CPP layer when used in the lithium battery production process, thereby ensuring that the aluminum-plastic film has good protection performance and avoids battery leakage.

[0114] The present disclosure also provides a lithium battery, comprising the high temperature resistant aluminum-plastic film described in the above embodiment.

[0115] In this embodiment, the lithium battery prepared by using the high temperature resistant aluminum-plastic film disclosed in the present invention will not leak at high temperatures and has good safety performance.

[0116] Examples are listed below, but it should be noted that the following examples do not exhaust all possible situations, and the materials used in the following examples can be obtained from commercial channels unless otherwise specified.

[0117] Example 1

[0118] 1. Preparation of new polyurethane adhesive: 100 parts of polyhydroxy compound, 25 parts of polyisocyanate compound, 8 parts of amine catalyst, and 150 parts of ethyl acetate.

[0119] The production steps are as follows:

[0120] Step 1: Prepare the required materials according to the new polyurethane adhesive ratio table;

[0121] Step 2: Mix the amine catalyst and ethyl acetate and add them into the reactor, turn on the reactor stirrer, adjust the speed to 250r / min, and keep stirring for 5 minutes;

[0122] Step 3: Add the polyhydroxy compound into the reactor at a speed of 250 r / min and stir and mix thoroughly for 15 minutes;

[0123] Step 4: Mix the polyisocyanate compound and ethyl acetate and add them into the reactor, adjust the speed to 350 r / min, and stir and mix thoroughly for 15 minutes to obtain the desired new polyurethane adhesive.

[0124] 2. Preparation of modified polyolefin adhesive: 100 parts of modified propylene chloride compound, 4.5 parts of diisocyanate compound, 4.5 parts of epoxy resin compound, and 70 parts of methylcyclohexane.

[0125] The production steps are as follows:

[0126] Step 1: Prepare the required materials according to the modified polyolefin adhesive ratio table;

[0127] Step 2: Add the modified chloropropylene compound into the reactor, turn on the reactor stirrer, adjust the speed to 250r / min, and keep stirring for 5 minutes;

[0128] Step 3: Mix the diisocyanate compound and methylcyclohexane and add them into the reactor, adjust the speed to 250r / min, and the time is 15min;

[0129] Step 4: Mix the epoxy resin compound and methylcyclohexane and add them into the reactor, adjust the speed to 250 r / min, and stir and mix thoroughly for 25 minutes to obtain the desired new polyurethane adhesive.

[0130] 3. Making aluminum-plastic film:

[0131] Step 1: Perform surface passivation treatment on the aluminum foil layer of required thickness to make the aluminum foil layer corrosion-resistant;

[0132] Step 2: using a novel polyurethane adhesive to perform a first composite treatment on the surface passivated aluminum foil layer and the nylon layer to obtain a first composite film layer;

[0133] Step 3: performing a first aging treatment on the first composite film layer at a temperature of 85° C. for 4 days;

[0134] Step 4: using a modified polyolefin adhesive to perform a second composite treatment on the first composite film layer after the first aging treatment and the CPP layer to obtain a second composite film layer;

[0135] Step 5: Perform a second aging treatment on the second composite film layer at a temperature of 70° C. for 6 days to obtain an aluminum-plastic film.

[0136] Example 2

[0137] The difference from Example 1 is that the ratio of the new polyurethane adhesive is different. The new polyurethane adhesive is prepared by: 100 parts of polyhydroxy compound, 15 parts of polyisocyanate compound, 4 parts of amine catalyst, and 150 parts of ethyl acetate.

[0138] Example 3

[0139] The difference from Example 1 is that the modified polyolefin binder has a different ratio: the modified polyolefin binder is prepared by: 100 parts of modified propylene chloride compound, 2.5 parts of diisocyanate compound, 2.5 parts of epoxy resin compound, and 70 parts of methylcyclohexane.

[0140] Example 4

[0141] The difference from Example 1 is that the ratios of the new polyurethane binder and the modified polyolefin binder are different. The new polyurethane binder is prepared by: 100 parts of polyhydroxy compound, 15 parts of polyisocyanate compound, 4 parts of amine catalyst, and 150 parts of ethyl acetate;

[0142] Modified polyolefin adhesive preparation: 100 parts of modified propylene chloride compound, 2.5 parts of diisocyanate compound, 2.5 parts of epoxy resin compound, and 70 parts of methylcyclohexane.

[0143] Example 5

[0144] The difference from Example 1 is that the ratios of the new polyurethane binder and the modified polyolefin binder are different. The new polyurethane binder is prepared by: 100 parts of polyhydroxy compound, 20 parts of polyisocyanate compound, 5 parts of amine catalyst, and 150 parts of ethyl acetate;

[0145] Modified polyolefin adhesive preparation: 100 parts of modified propylene chloride compound, 3.5 parts of diisocyanate compound, 3.5 parts of epoxy resin compound, and 70 parts of methylcyclohexane.

[0146] Comparative Example 1

[0147] The difference from Example 1 is that a traditional adhesive is selected, and the preparation process of the aluminum-plastic film is consistent with that of Example 1.

[0148] Comparative Example 2

[0149] The difference from Example 1 is that the ratios of the new polyurethane binder and the modified polyolefin binder are different. The new polyurethane binder is prepared by: 100 parts of polyhydroxy compound, 20 parts of polyisocyanate compound, 5 parts of amine catalyst, and 150 parts of ethyl acetate;

[0150] Modified polyolefin adhesive preparation: 100 parts of modified propylene chloride compound, 3.5 parts of diisocyanate compound, 3.5 parts of epoxy resin compound, and 70 parts of methylcyclohexane.

[0151] The aluminum-plastic films of Examples 1-5 and Comparative Examples 1-2 were made into lithium batteries for high temperature resistance test. Specifically, the delamination of the aluminum-plastic films after being placed for 6 seconds by gradient heating was tested. The test results are shown in Table 1.

[0152] Table 1

[0153]

[0154] According to the group standard TCIAPS0005-2018 for aluminum-plastic composite films for lithium-ion batteries, peel strength tests and peel strength tests after electrolyte corrosion were performed on Examples 1-5 and Comparative Examples 1-2, where NY is the nylon layer, L is the aluminum foil layer, and CPP is the CPP laminating layer. The test results are shown in Table 2.

[0155] Table 2

[0156]

[0157] As can be seen from Table 1, the changes in the formula of the new polyurethane adhesive and the modified polyolefin adhesive have an impact on the high temperature resistance of the aluminum-plastic film. Among them, Examples 1-5 and Comparative Example 2 using the new polyurethane adhesive and the modified polyolefin adhesive are both improved to 195°C in high temperature resistance compared to the traditional adhesive in Comparative Example 1. As the formula of the new polyurethane adhesive and the modified polyolefin adhesive changes, the high temperature resistance is improved to a certain extent, and the high temperature resistance of Example 1 even reaches 230°C. It can be seen that Example 1 is the best embodiment, that is, the formula of the new polyurethane adhesive is preferably 100 parts of polyhydroxy compounds, 25 parts of polyisocyanate compounds, 8 parts of amine catalysts, and 150 parts of ethyl acetate, and the formula of the modified polyolefin adhesive is preferably 100 parts of modified chloropropylene compounds, 4.5 parts of diisocyanate compounds, 4.5 parts of epoxy resin compounds, and 70 parts of methylcyclohexane.

[0158] As can be seen from Table 2, the changes in the formula of the new polyurethane adhesive and the modified polyolefin adhesive have an impact on the peel strength between the nylon layer and the aluminum foil layer, the peel strength between the aluminum foil layer and the CPP layer, and the peel strength of the aluminum-plastic film after immersion in the electrolyte. Among them, the peel strength of the new polyurethane adhesive and the modified polyolefin adhesive is improved to a certain extent compared with the traditional adhesive, but the formulas of Example 4 and Example 5 are not much different from the traditional adhesive in improving the peel strength, and Example 1 has the best peel strength improvement effect, which greatly improves the peel strength and corrosion resistance between the film layers of the aluminum-plastic film. It can be seen that Example 1 is the best embodiment.

[0159] Further, by comparing Example 1 and Comparative Example 2, it is found that ethyl acetate plays a key role in the novel polyurethane binder system, can dilute amine catalysts and polyisocyanate compounds, avoid the situation of forming particles due to excessive concentration when amine catalysts and polyisocyanate compounds are added, and ensure that the novel polyurethane adhesive layer has good bonding strength and flatness. Similarly, methylcyclohexane plays a key role in the modified polyolefin binder system, can dilute diisocyanate compounds and epoxy resin compounds, avoid the situation of forming particles due to excessive concentration when amine diisocyanate compounds and epoxy resin compounds are added, and ensure that the modified polyolefin adhesive layer has good bonding strength and flatness. Thereby effectively improving the peel strength between each film layer in the aluminum-plastic film.

[0160] In summary, the aluminum-plastic film prepared by the preparation method of the high-temperature resistant aluminum-plastic film disclosed in the present invention not only has good high-temperature resistance, but also has good peel strength and good corrosion resistance, so that it has good protection performance when used in lithium-ion batteries and avoids battery leakage.

[0161] Compared with the prior art, the present invention has at least the following advantages:

[0162] The passivated aluminum foil layer and the nylon layer are subjected to a first composite treatment by using a new polyurethane adhesive to ensure that the new polyurethane adhesive can cover the connecting surface between the aluminum foil layer and the nylon layer. The first composite film layer is subjected to a first aging treatment to allow the components in the new polyurethane adhesive to fully react, thereby forming an adhesive layer with strong bonding force and good temperature resistance, thereby effectively improving the bonding force between the aluminum foil layer and the nylon layer. The first composite film layer and the CPP layer are subjected to a second composite treatment by using a modified polyolefin adhesive to ensure that the modified polyolefin glue can cover the connecting surface between the passivated aluminum foil layer and the CPP layer, and the second composite film layer is subjected to a second aging treatment to allow the components in the modified polyolefin adhesive to fully react, thereby forming an adhesive layer with strong bonding force and good heat resistance, so that the bonding force between the aluminum foil layer and the CPP layer is effectively improved, so that the high-temperature resistant aluminum-plastic film is not prone to delamination, blistering, and poor heat sealing of the CPP layer when used in the lithium battery production process, thereby ensuring that the aluminum-plastic film has good protection performance and avoids battery leakage.

[0163] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. A method for preparing a high temperature resistant aluminum-plastic film, characterized in that: The steps include: Obtaining aluminum foil layer, nylon layer and CPP layer; Performing surface passivation treatment on the aluminum foil layer; Preparation of new polyurethane adhesive; The aluminum foil layer and the nylon layer having the surface passivated are subjected to a first composite treatment using the novel polyurethane adhesive to obtain a first composite film layer; performing a first aging treatment on the first composite film layer; preparing a modified polyolefin adhesive; Using the modified polyolefin adhesive, the first composite film layer after the first aging treatment and the CPP layer are subjected to a second composite treatment to obtain a second composite film layer; The second composite film layer is subjected to a second aging treatment to obtain a high temperature resistant aluminum-plastic film.

2. The method for preparing a high temperature resistant aluminum-plastic film according to claim 1, characterized in that: The novel polyurethane adhesive comprises the following components in parts by mass:

3. The method for preparing the high temperature resistant aluminum-plastic film according to claim 2, characterized in that: The specific operation steps for preparing the novel polyurethane binder are: The amine catalyst and the ethyl acetate are mixed and added into the reaction kettle to perform a first stirring operation; Adding the polyhydroxy compound into the reactor to perform a second stirring operation; The polyisocyanate compound and the ethyl acetate are mixed and added into the reaction kettle to perform a third stirring operation to obtain the novel polyurethane adhesive.

4. The method for preparing a high temperature resistant aluminum-plastic film according to claim 1, characterized in that: The specific operation steps of using the novel polyurethane adhesive to perform the first composite treatment on the aluminum foil layer and the nylon layer after the surface passivation treatment are as follows: Applying the novel polyurethane adhesive on the nylon layer; Aligning and laminating one side of the nylon layer with the novel polyurethane adhesive with one side of the aluminum foil layer to form a first composite film layer; The first composite film layer is subjected to a first rolling operation by a rolling press.

5. The method for preparing a high temperature resistant aluminum-plastic film according to claim 1, characterized in that: The modified polyolefin adhesive comprises the following components in parts by mass:

6. The method for preparing the high temperature resistant aluminum-plastic film according to claim 5, characterized in that: The specific steps of preparing the modified polyolefin binder are: Adding the modified chloropropylene compound into the reactor to perform a fourth stirring operation; The diisocyanate compound and the methylcyclohexane are mixed and added into the reactor to perform a fifth stirring operation; The epoxy resin compound and the methylcyclohexane are mixed and added into the reaction kettle to perform a sixth stirring operation to obtain the modified polyolefin adhesive modified polyolefin glue.

7. The method for preparing a high temperature resistant aluminum-plastic film according to claim 1, characterized in that: The specific operation steps of using the modified polyolefin adhesive to perform a second composite treatment on the first composite film layer after the first aging treatment and the CPP layer are as follows: coating the modified polyolefin adhesive on the CPP layer; Aligning and laminating one side of the CPP layer with the modified polyolefin adhesive with the other side of the aluminum foil layer of the first composite film layer to form a second composite film layer; The second composite film layer is subjected to a second rolling operation by the rolling machine.

8. The method for preparing a high temperature resistant aluminum-plastic film according to claim 1, characterized in that: After the step of performing a second aging treatment on the second composite film layer, the method further includes the following steps: The second composite film layer after the second aging treatment is cut to obtain a high temperature resistant aluminum-plastic film.

9. A high temperature resistant aluminum-plastic film, characterized in that: The high temperature resistant aluminum-plastic film is prepared by the preparation method of any one of claims 1 to 8.

10. A lithium battery, characterized in that: It includes the high temperature resistant aluminum-plastic film as described in claim 9.

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