KR-102963869-B1 - Pouch-type battery cell and battery module including the same

KR102963869B1KR 102963869 B1KR102963869 B1KR 102963869B1KR-102963869-B1

Abstract

A pouch-type battery cell according to the present invention comprises: an electrode assembly in which a positive plate and a negative plate are repeatedly arranged to face each other with a separator in between; a pouch outer material that seals and houses the electrode assembly; and an electrode lead that is connected to an electrode tab bundle extending from the electrode assembly inside the pouch outer material and protrudes to the outside of the pouch outer material, wherein the electrode lead comprises a first electrode lead and a second electrode lead that face each other, extend in the same direction, and have the same polarity, and between the first electrode lead and the second electrode lead, a rupture sealing member having one surface bonded to the first electrode lead and the other surface bonded to the second electrode lead.

Inventors

박정훈
정혜미
김수열

Assignees

주식회사 엘지에너지솔루션

Dates

Publication Date: 20260512
Application Date: 20230320
Priority Date: 20221205

Claims (10)

An electrode assembly in which positive and negative plates are repeatedly arranged facing each other with a separator in between; A pouch outer material for sealing and housing the above electrode assembly; and It includes an electrode lead that is connected to an electrode tab bundle extending from the electrode assembly inside the pouch outer material and protrudes to the outside of the pouch outer material. The above electrode leads are provided with a first electrode lead and a second electrode lead that face each other, extend in the same direction, and have the same polarity. The electrode tab bundle is divided into two bundles and includes a first electrode tab bundle and a second electrode tab bundle, the first electrode tab bundle is connected to the first electrode lead, and the second electrode tab bundle is connected to the second electrode lead. Between the first electrode lead and the second electrode lead, a rupture sealing member is included, wherein one side is bonded to the first electrode lead and the other side is bonded to the second electrode lead. The above pouch outer material includes a sealing portion formed by heat-fusion of the edges, and A pouch-type battery cell characterized in that the first electrode lead and the second electrode lead are overlapped to contact each other on the outer side of the sealing portion or bonded with a conductive adhesive to function as a single electrode terminal.
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In paragraph 1, A pouch-type battery cell characterized in that, inside the pouch outer material, the first electrode lead and the second electrode lead are separated from each other.
In paragraph 1, A pouch-type battery cell characterized in that the sealing portion comprises a first lead film for bonding the first electrode lead and the pouch outer material, and a second lead film for bonding the second electrode lead and the pouch outer material.
In paragraph 4, A pouch-type battery cell characterized in that the bonding force of the rupture sealing member is provided to be weaker than the bonding force of the first lead film or the second lead film.
In paragraph 4, The above-mentioned rupture sealing member is, A pouch-type battery cell characterized by extending to the outside of the pouch outer material together with the first electrode lead and the second electrode lead.
In paragraph 6, The above-mentioned rupture sealing member is, A pouch-type battery cell characterized by being made of a material that undergoes thermal deformation and is lost at a temperature above a predetermined temperature.
In paragraph 6, A pouch-type battery cell characterized in that the first electrode lead and the second electrode lead are bonded with a conductive adhesive on the outside of the pouch outer material.
In paragraph 8, A pouch-type battery cell characterized in that the above-described rupture sealing member includes a through hole through which the conductive adhesive can pass.
A battery module characterized by including a pouch-type battery cell according to any one of claims 1 and 3 through 9.

Description

Pouch-type battery cell and battery module including the same The present invention relates to a secondary battery, and more specifically, to a pouch-type battery cell having low heat generation and excellent safety against thermal events under high-speed charging or high-output conditions, and a battery module including the same. With the significant increase in technological development and demand for various mobile devices, electric vehicles, and energy storage systems (ESS), interest in and demand for secondary batteries as an energy source are rapidly rising. While nickel-cadmium and nickel-hydrogen batteries were conventionally widely used as secondary batteries, lithium-ion batteries are now being widely utilized. Compared to nickel-based batteries, lithium-ion batteries exhibit almost no memory effect, allowing for free charging and discharging, have a very low self-discharge rate, and possess high energy density. Lithium secondary batteries primarily use lithium-based oxides and carbon materials as positive and negative active materials, respectively. A lithium secondary battery comprises an electrode assembly in which a positive plate and a negative plate, each coated with these positive and negative active materials, are arranged with a separator in between, and an outer casing, namely a battery case, that seals and houses the electrode assembly together with an electrolyte. Lithium secondary batteries can be classified according to the shape of the casing into can-type secondary batteries, in which the electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which the electrode assembly is housed in a pouch made of aluminum laminate sheets. These secondary batteries can generally be manufactured through a process in which an electrolyte is injected while the electrode assembly is housed in the casing, and the casing is sealed. Pouch-type rechargeable batteries are highly preferred for the production of medium to large battery modules because, compared to other types of rechargeable batteries, they are easy to stack, lightweight, and have a high energy density relative to volume. Referring to FIGS. 1 and 2, such a pouch-type secondary battery (1) may include an electrode assembly, electrode tabs, electrode leads, and a pouch outer casing. The electrode tabs may include positive tabs extending from the positive plates of the electrode assembly and negative tabs extending from the negative plates of the electrode assembly. The positive tabs and negative tabs may converge in a certain direction and then be joined to the corresponding electrode leads by methods such as resistance welding, ultrasonic welding, or laser welding. The electrode leads may be exposed to the outside of the pouch outer casing and function as electrode terminals of the pouch-type secondary battery. Meanwhile, in conventional pouch-type secondary batteries, as shown in FIG. 2, the electrode tabs are collectively connected to a single electrode lead. This structure, in which multiple electrode tabs (positive tabs or negative tabs) are connected to a single electrode lead, causes a bottleneck in current flow, which hinders high-speed charging and increases heat generation in high-output situations. Furthermore, when gas is generated inside the pouch-type battery cell during a thermal runaway, and the internal pressure of the pouch-type battery cell reaches a level exceeding the limit pressure that the sealing part (S) can withstand, the sealing part (S) may open, causing high-temperature gas and particles to be explosively ejected all at once due to the high pressure. (Here, particles refer to electrode fragments or active materials detached from the electrode assembly.) The high-pressure, high-temperature gas and particles ejected from the pouch-type battery cell in this manner can cause significant thermal damage to adjacent pouch-type battery cells or the surrounding environment. Therefore, there is a need to develop a pouch-type battery cell capable of preventing explosions in the event of a thermal event. The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a schematic perspective view illustrating a pouch-type battery cell according to the prior art. FIG. 2 is a schematic cross-sectional view of a pouch-type battery cell according to the prior art. FIG. 3 is a schematic perspective view of a pouch-type battery cell according to one embodiment of the present invention. FIG. 4 is a schematic diagram showing the bonding structure of an electrode lead and an electrode tab according to one embodiment of the present invention. Figure 5 is a schematic p