KR-20260066542-A - MANUFACTURING METHOD OF BATTERY SEPARATOR

KR20260066542AKR 20260066542 AKR20260066542 AKR 20260066542AKR-20260066542-A

Abstract

According to the present disclosure, a method for manufacturing a battery separator capable of reducing damage to a substrate layer and increasing the fixing strength of an adhesive layer may include: a first step of obtaining a structure comprising a substrate layer including a polyolefin-based film and a surface layer including polymer particles disposed on one or both sides of the substrate layer; and a second step of heating one side of the structure to set the temperature of one side of the structure to be at least 30°C higher than the temperature of the other side of the structure.

Inventors

이주성
김진우

Assignees

주식회사 엘지화학

Dates

Publication Date: 20260512
Application Date: 20241104

Claims (11)

A first step of obtaining a structure comprising a substrate layer including a polyolefin-based film and a surface layer disposed on one or both sides of the substrate layer and including polymer particles; and A second step of heating one side of the structure to set the temperature of one side of the structure to be at least 30°C higher than the temperature of the other side of the structure; A method for manufacturing a battery separator comprising
In Article 1, The melting point of the above polyolefin-based film is 137 ℃ or lower, and A method for manufacturing a battery separator in which the glass transition temperature of the polymer particles is 40°C or higher.
In Article 2, A method for manufacturing a battery separator in which the melting point of the polymer particles is 100°C or higher.
In Article 1, A method for manufacturing a battery separator comprising the above structure disposed between the surface layer and the substrate layer and further including an inner layer containing inorganic particles.
In Article 1, The above second step is a method for manufacturing a battery separator in which one side of the structure is contacted with a heating roll.
In Article 5, A method for manufacturing a battery separator, wherein the set temperature of the heating roll is within the range of 70 ℃ to 130 ℃.
In Article 5, The above second step is a method for manufacturing a battery separator carried out in an oven at a set temperature of 40°C or lower.
In Article 1, The above second step is a method for manufacturing a battery separator by discharging heated compressed air to one side of the structure using an air-turn bar.
In Article 9, A method for manufacturing a battery separator in which the structure is spaced apart from the air-turn bar in the second step above.
In Article 1, The above second step is a method for manufacturing a battery separator by heating one side of the structure with an infrared heater.
In Article 10, The above second step is a method for manufacturing a battery separator in which the other side of the structure is brought into contact with a cooling roll.

Description

Manufacturing Method of Battery Separator The present disclosure relates to a method for manufacturing a battery separator. The battery may include a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The separator may include a substrate layer and an adhesive layer disposed between one or both sides of the substrate layer. The separator may be attached to the positive electrode and/or the negative electrode through the adhesive layer. The adhesive layer may include an adhesive polymer component. The adhesive polymer component may be a polymer particle having a particle structure. If the polymer particle is well fixed to the separator, defects in the battery assembly process in which the separator is used can be reduced. There is a need to develop a technology that allows the polymer particle to be well fixed to the separator while simultaneously reducing electrical resistance. FIG. 1 shows a schematic diagram of a first embodiment of the present disclosure. FIG. 2 shows a schematic diagram of a second embodiment of the present disclosure. FIG. 3 shows a schematic diagram of a third embodiment of the present disclosure. The present disclosure is described in detail below with reference to the accompanying drawings. FIG. 1 shows a schematic diagram of a first embodiment of the present disclosure. FIG. 2 shows a schematic diagram of a second embodiment of the present disclosure. FIG. 3 shows a schematic diagram of a third embodiment of the present disclosure. One embodiment of the present disclosure relates to a method for manufacturing a battery separator. The above battery may include any device that performs an electrochemical reaction. The above battery may refer to any type of primary or secondary battery, fuel cell, solar cell, or capacitor, etc. In particular, the above battery may refer to a lithium secondary battery. The above lithium secondary battery may refer to a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery, etc. The above separator can be applied to a battery to prevent contact between electrodes (positive and negative electrodes). Additionally, the separator can allow a charge carrier (e.g., metal ions) to move between the electrodes. The battery may be a lithium-ion battery. The separator can allow lithium ions to move within the battery. The method of the present disclosure may include at least the step of obtaining a structure (SEP) of a specific structure (step 1) and the step of heating the structure (SEP) to increase the interlayer fixing force of the structure (SEP) (step 2). The method of the present disclosure can obtain a structure (SEP) comprising a substrate layer (SUB) and a surface layer (ORG) in the first step. The above substrate layer (SUB) may be porous. Fluid may move from one side of the substrate layer (SUB) to another side through the pores of the substrate layer (SUB). The above substrate layer (SUB) may include a porous polyolefin-based film. Here, a polyolefin-based porous film refers to a porous film containing a polyolefin resin as a main component. The above polyolefin-based porous film may contain the polyolefin-based resin in an amount of 50 volume% or more, 90 volume% or more, or 95 volume% or more of the total material constituting the polyolefin-based porous film. The weight average molecular weight of the component included in the polyolefin resin may be 3× 10⁵ to 25× 10⁶ . If the weight average molecular weight of the component included in the polyolefin resin is 1 million or more, the strength of the separator containing the polyolefin porous film may be improved. The above polyolefin resin may include a thermoplastic resin. The thermoplastic resin may include a homopolymer (e.g., polyethylene, polypropylene, polybutene) or copolymer (e.g., ethylene-propylene copolymer) formed by polymerizing monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and 1-hexene. The above polyolefin-based porous film may be a layer comprising the polyolefin-based resin alone, or a layer comprising two or more of the polyolefin-based resins. Among these, polyethylene and high molecular weight polyethylene having ethylene as a main backbone can stop (shut down) the flow of excessive current at a lower temperature. In addition, the polyolefin-based porous film may additionally include components other than the polyolefin-based resin that do not impair the function of the film. The surface layer (ORG) may be disposed on one or both sides of the substrate layer (SUB). The surface layer (ORG) may be an adhesive layer. The surface layer (ORG) may attach the separator to the electrode when the separator is applied to a battery. The surface layer (ORG) may include an adhesive polymer component. The type of adhesive polymer is not particularly limited. The adhesive polymer may include, for example, (me