KR-20260064556-A - NONAQUEOUS ELECTROLYTE SECONDARY BATTERY POROUS LAYER AND USE THEREOF

Abstract

A porous layer for a non-aqueous electrolyte secondary battery having excellent ion permeability when pressurized is provided. The porous layer for a non-aqueous electrolyte secondary battery according to the present disclosure has a product of the acid peak density Spd [1/㎛ 2 ] calculated from an image obtained by observing the surface of the porous layer for a non-aqueous electrolyte secondary battery by a laser microscope and the arithmetic mean curvature Spc [1/㎛] of the acid peaks being 40 [1/㎛ 3 ] or more.

Inventors

• 와타나베, 덴카이
• 오제키, 도모아키
• 마츠미네, 리쿠
• 이시이, 다이가

Assignees

• 스미또모 가가꾸 가부시키가이샤

Dates

Publication Date

20260507

Application Date

20251024

Priority Date

20241031

Claims (9)

1. It is a porous layer for a non-aqueous electrolyte secondary battery, and A porous layer for a non-aqueous electrolyte secondary battery, wherein the product of the acid peak density Spd [1/㎛ 2 ] calculated from an image obtained by observing the surface of the porous layer for the non-aqueous electrolyte secondary battery by a laser microscope and the arithmetic mean curvature Spc [1/㎛ 3] of the acid peaks is 40 [1/㎛ 3 ] or more.
2. A porous layer for a non-aqueous electrolyte secondary battery according to claim 1, wherein the peak density Spd of the acid is 5.0 [1/㎛ 2 ] or higher.
3. A porous layer for a non-aqueous electrolyte secondary battery according to claim 1, wherein the surface area increment Sdr calculated from an image obtained by observing the surface of the porous layer for a non-aqueous electrolyte secondary battery by a laser microscope is 0.10 or greater.
4. A porous layer for a non-aqueous electrolyte secondary battery according to claim 1, wherein the gradient increment Sdq calculated from an image obtained by observing the surface of the porous layer for a non-aqueous electrolyte secondary battery by a laser microscope is 0.5 or greater.
5. A porous layer for a non-aqueous electrolyte secondary battery according to claim 1, comprising at least one resin selected from the group consisting of acrylic resin, aromatic polyamide, polyimide, polyamideimide, and polyvinylidene fluoride.
6. A laminate for a non-aqueous electrolyte secondary battery having a porous layer for a non-aqueous electrolyte secondary battery described in claim 1, and a particle layer provided on at least one side of the porous layer for a non-aqueous electrolyte secondary battery.
7. Polyolefin porous film and, A laminated separator for a non-aqueous electrolyte secondary battery, comprising a porous layer for a non-aqueous electrolyte secondary battery described in any one of claims 1 to 5 or a laminate for a non-aqueous electrolyte secondary battery described in claim 6, laminated on at least one side of the above-mentioned polyolefin porous film.
8. A non-aqueous electrolyte secondary battery member having a positive electrode, a stacked separator for a non-aqueous electrolyte secondary battery described in claim 7, and a negative electrode stacked in this order.
9. A non-aqueous electrolyte secondary battery having a stacked separator for a non-aqueous electrolyte secondary battery as described in claim 7.

Description

Porous layer for non-aqueous electrolyte secondary battery and use thereof The present invention relates to a porous layer for a non-aqueous electrolyte secondary battery, a laminate for a non-aqueous electrolyte secondary battery, a laminated separator for a non-aqueous electrolyte secondary battery, a member for a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery. Non-aqueous electrolyte secondary batteries, especially lithium-ion secondary batteries, are widely used as batteries for personal computers, mobile phones, portable information terminals, and vehicles because they have a high energy density. Lithium-ion secondary batteries generally have a separator between a positive electrode and a negative electrode. For example, Patent Document 1 discloses a separator for a non-aqueous secondary battery comprising a heat-resistant porous layer containing an aromatic resin and inorganic particles, and an adhesive layer containing adhesive resin particles containing a phenyl group-containing acrylic resin. FIG. 1 is a schematic diagram illustrating the schematic structure of a stacked separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention. FIG. 2 is a schematic diagram illustrating the schematic structure of a stacked separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention. FIG. 3 is a schematic diagram illustrating the schematic structure of a stacked separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention. FIG. 4 is a schematic diagram illustrating the schematic structure of a stacked separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention. FIG. 5 is a schematic diagram illustrating the schematic structure of a stacked separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention. One embodiment of the present invention is described below, but the present invention is not limited thereto. Furthermore, unless otherwise specified in this specification, "A to B" indicating a numerical range means "A or more, B or less." [1. Porous layer for non-aqueous electrolyte secondary batteries] A porous layer for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention has a product of the acid peak density Spd [1/㎛ 2 ] calculated from an image obtained by observing the surface of the porous layer for a non-aqueous electrolyte secondary battery by a laser microscope and the arithmetic mean curvature Spc [1/㎛] of the acid peaks of 40 [1/㎛ 3 ] or more. Hereinafter, the porous layer for a non-aqueous electrolyte secondary battery is also simply referred to as a porous layer. Spd is defined in ISO 25178 and represents the number of peaks per unit area. A large Spd indicates a high number of contact points between the surface of the porous layer and other objects. Spc is also defined in ISO 25178 and represents the average curvature of the peaks. A large Spc indicates that the shape of the contact points with other objects on the surface of the porous layer is sharp. A small Spc indicates that the shape of the contact points with other objects on the surface of the porous layer is rounded. Spd and Spc can be measured using a laser microscope. More specific measurement methods are described in the examples. During the charging and discharging of a non-aqueous electrolyte secondary battery, the electrode expands, and the separator may be compressed as a result. When a porous layer and, if necessary, a particle layer exist on the separator, there is a risk that the pores of the porous layer may be crushed by compression, and/or that the particles contained in the particle layer may be crushed by compression, thereby blocking the pores of the porous layer, which may increase the air permeability, i.e., worsen the ion permeability. The inventors, through repeated research, discovered that ion permeability under pressurization can be improved by controlling the product of Spd and Spc to be 40 [1/ ㎛³ ] or more. Improving ion permeability under pressurization means, for example, that the increase in air permeability after pressurization is reduced. If the product of Spd and Spc is 40 [1/ ㎛³ ] or greater, it indicates that there are many convex parts (peaks) on the surface of the porous layer and that the shape of the convex parts on the surface of the porous layer is pointed. In this state, the surface area of the porous layer increases, so it is difficult for the pores on the surface of the porous layer to become clogged even when compressed, and even if a particle layer is present, it is difficult for the pores to be covered by the particles. Therefore, it is thought that ion permeability is unlikely to deteriorate even when pressurized. The product of Spd and Spc may be 45 [1/ ㎛³ ] or