EP-4742380-A1 - POUCH SHEET, POUCH-TYPE BATTERY CASE, AND METHOD FOR MANUFACTURING BATTERY CASE

EP4742380A1EP 4742380 A1EP4742380 A1EP 4742380A1EP-4742380-A1

Abstract

The present disclosure relates to a pouch sheet, a pouch-type battery case and a method for manufacturing a battery case, and the pouch sheet that is formed into a pouch-type battery case includes a first polymer layer located at an outermost side, a second polymer layer located at an opposite outermost side and a metal layer located between the first polymer layer and the second polymer layer, wherein the metal layer is located at a side of a neutral plane of the pouch sheet.

Inventors

LEE, WAN SOO
KANG, MIN HYEONG
YU, HYUNG KYUN
HWANG, SOO JI
SONG, DAE WOONG
SHIN, JI HYUN
KIM, Gi Woung

Assignees

LG Energy Solution, Ltd.

Dates

Publication Date: 20260513
Application Date: 20240906

Claims (11)

A pouch sheet that is formed into a pouch-type battery case, the pouch sheet comprising: a first polymer layer located at an outermost side; a second polymer layer located at an opposite outermost side; and a metal layer located between the first polymer layer and the second polymer layer, wherein the metal layer is located at a side of a neutral plane of the pouch sheet.
The pouch sheet according to claim 1, wherein the second polymer layer includes a plurality of layers that are separable from each other.
The pouch sheet according to claim 1, wherein the second polymer layer includes: a base layer; and a reinforcement layer covering the base layer at an outer side, and having a larger thickness than the base layer.
The pouch sheet according to claim 3, wherein the first polymer layer, the metal layer and the base layer are laminated together, and wherein the reinforcement layer is separably attached to the base layer.
The pouch sheet according to claim 3, wherein the neutral plane of the pouch sheet from which the reinforcement layer is removed passes through the metal layer.
The pouch sheet according to claim 1, wherein a thickness of the metal layer is larger than a thickness of the second polymer layer.
A pouch-type battery case having a recessed cup portion and a terrace portion disposed around the cup portion, wherein the cup portion and the terrace portion include: a first polymer layer located at an innermost side; a second polymer layer located at an outermost side; and a metal layer located between the first polymer layer and the second polymer layer, and wherein the metal layer is located at a more inward side than a neutral plane of the case.
A method for manufacturing a battery case, comprising: preparing a pouch sheet including a first polymer layer located at an innermost side, a second polymer layer located at an outermost side, and a metal layer located between the first polymer layer and the second polymer layer; and forming a recessed cup portion in the pouch sheet, wherein the metal layer is located at a more inward side than a neutral plane of the pouch sheet.
The method for manufacturing the battery case according to claim 8, wherein the second polymer layer includes: a base layer; and a reinforcement layer covering the base layer at an outer side, and having a larger thickness than the base layer.
The method for manufacturing the battery case according to claim 9, further comprising: removing the reinforcement layer after forming the cup portion.
The method for manufacturing the battery case according to claim 9, wherein preparing the pouch sheet comprises includes: preparing a laminated sheet of the first polymer layer, the metal layer and the base layer; and covering the base layer with the reinforcement layer at the outer side.

Description

TECHNICAL FIELD CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to Korean Patent Application No. 10-2023-0118632 filed on September 6, 2023 and Korean Patent Application No. 10-2024-0121124 filed on September 5, 2024 in the Republic of Korea, the disclosures of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to a pouch sheet, a pouch-type battery case and a method for manufacturing a battery case. BACKGROUND ART Recently, with rising prices of energy sources caused by depletion of fossil fuels and growing concerns about environmental pollution, the need for eco-friendly alternative energy sources is an essential factor for future life. In this circumstance, studies have been conducted on a variety of energy production technologies such as solar, wind and tidal energy, and energy storage devices such as batteries for using the produced electrical energy more efficiently are of great interest. Moreover, with technology development and increasing demand for electronic mobile devices and electric vehicles using batteries, the demand for batteries as an energy source is rapidly increasing, and accordingly many studies are being conducted on batteries that meet a variety of needs. Batteries are gaining much attention as an energy source in a broad range of products including mobile devices and electric vehicles. In particular, secondary batteries are seen as a superior energy resource that can replace the use of the existing products using fossil fuels, and because they do not produce by-products from the use of energy, attention is paid to secondary batteries as an eco-friendly energy source. On the other hand, secondary batteries are attracting attention as a power source for electric vehicles (EVs), hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (Plug-In HEVs) proposed as a solution to air pollution from gasoline vehicles and diesel vehicles using fossil fuels. That is, secondary batteries are used in the form of a battery pack including a plurality of battery modules. Secondary batteries, especially pouch-type secondary batteries undergo a process of forming a cup portion to manufacture a pouch battery case, and in this instance, stretching occurs in the case, in particular, a metal layer included in the case. In particular, bending of the metal layer occurs at the corner of the cup portion, and in this instance, the metal layer is subjected to additional tensile force by the bending and there is a risk of excessive stretching of the metal layer. As a consequence, it is impossible to form the pouch-type case more deeply. SUMMARY TECHNICAL PROBLEM The present disclosure is designed to solve the above-described problem, and therefore the present disclosure is directed to providing a pouch sheet in which a metal layer is located at a more inward side than a neutral plane of the pouch sheet to prevent excessive stretching of the metal layer and improve formability. The present disclosure is further directed to providing a pouch-type battery case manufactured using the pouch sheet and a method for manufacturing the same. TECHNICAL SOLUTION A pouch sheet according to an embodiment of the present disclosure may be formed into a pouch-type battery case. The pouch sheet may include a first polymer layer located at an outermost side; a second polymer layer located at an opposite outermost side; and a metal layer located between the first polymer layer and the second polymer layer, and the metal layer may be located at a side of a neutral plane of the pouch sheet. The second polymer layer may include a plurality of layers that is separable from each other. The second polymer layer may include a base layer; and a reinforcement layer covering the base layer at an outer side, and having a larger thickness than the base layer. The first polymer layer, the metal layer and the base layer may be laminated together, and the reinforcement layer may be separably attached to the base layer. The neutral plane of the pouch sheet from which the reinforcement layer is removed may pass through the metal layer. A thickness of the metal layer may be larger than a thickness of the second polymer layer. A pouch-type battery case according to an embodiment of the present disclosure may have a recessed cup portion and a terrace portion disposed around the cup portion. The cup portion and the terrace portion in the pouch-type case may include a first polymer layer located at an innermost side; a second polymer layer located at an outermost side; and a metal layer located between the first polymer layer and the second polymer layer, and the metal layer may be located at a more inward side than a neutral plane of the case. A method for manufacturing a battery case according to an embodiment of the present disclosure may include preparing a pouch sheet including a first polymer layer located at an innermost side, a second polymer layer located at an