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EP-4738476-A1 - ELECTRODE CURRENT COLLECTOR, LITHIUM SECONDARY BATTERY COMPRISING SAME, BATTERY MODULE, AND BATTERY PACK

EP4738476A1EP 4738476 A1EP4738476 A1EP 4738476A1EP-4738476-A1

Abstract

An electrode current collector according to the present invention includes a polymer resin layer; a first metal layer disposed on one surface of the polymer resin layer; and a second metal layer disposed on another surface of the polymer resin layer, wherein the first metal layer and the second metal layer include a shape memory alloy (SMA), and the shape memory alloy (SMA) is designed such that an external force is applied to the polymer resin layer through shape deformation when a temperature of the shape memory alloy (SMA) is greater than a predetermined temperature.

Inventors

  • KANG, GYUNG SOO
  • PARK, MIN SOO
  • YU, HYUNG KYUN

Assignees

  • LG Energy Solution, Ltd.

Dates

Publication Date
20260506
Application Date
20240821

Claims (10)

  1. An electrode current collector comprising: a polymer resin layer, a first metal layer disposed on one surface of the polymer resin layer, and a second metal layer disposed on another surface of the polymer resin layer, wherein the first metal layer and the second metal layer comprise a shape memory alloy (SMA), and the shape memory alloy (SMA) is designed such that an external force is applied to the polymer resin layer through shape deformation when a temperature of the shape memory alloy (SMA) is greater than a predetermined temperature.
  2. The electrode current collector of claim 1, wherein the shape memory alloy (SMA) comprises at least one of a copper-zinc alloy, a copper-tin alloy, a magnesium-copper alloy, a nickel-titanium alloy, and a copper-aluminum-nickel alloy.
  3. The electrode current collector of claim 1, wherein an amount of the shape memory alloy (SMA) is in a range of 20 wt% to 100 wt% based on a total weight of the metal layer.
  4. The electrode current collector of claim 1, wherein the polymer resin layer comprises at least one selected from the group consisting of a polyester-based resin, an epoxy-based resin, a phenol-based resin, a melamine-based resin, a urethane-based resin, a silicone-based resin, an EVA-based resin, a rubber-based resin, an acrylic-based resin, and a polyetherurethane-based resin.
  5. The electrode current collector of claim 1, wherein a thickness ratio of the polymer resin layer to the first metal layer or the second metal layer is in a range of 1:1 to 1:10.
  6. The electrode current collector of claim 1, wherein the polymer resin layer has a thickness of 3 µm to 18 µm.
  7. The electrode current collector of claim 1, wherein the first metal layer and the second metal layer each have a thickness of 10 µm to 30 µm.
  8. A lithium secondary battery comprising: an electrode assembly having a structure in which a plurality of electrodes and a plurality of separators are alternatingly stacked, wherein the electrodes each comprise an electrode current collector and an electrode active material layer disposed on the electrode current collector, and at least one of a plurality of electrode current collectors is the electrode current collector of any one of claims 1 to 7.
  9. A battery module comprising a plurality of the lithium secondary batteries of claim 8.
  10. A battery pack comprising a plurality of the battery modules of claim 9.

Description

TECHNICAL FIELD This application claims the benefit of priority from Korean Patent Application No. 10-2023-0110180, filed on August 22, 2023, the disclosure of which is incorporated by reference herein. The present invention relates to an electrode current collector, and a lithium secondary battery, a battery module, and a battery pack which include the same. BACKGROUND ART Demand for batteries as an energy source has been significantly increased as technology development and demand with respect to electric vehicles and energy storage systems (ESS) have increased, and accordingly, research is being conducted on batteries that may meet various needs. Particularly, in order to use the battery for a longer period of time on a single charge, it is necessary to increase capacity of the battery, and a technique for preparing a large-area electrode is essential for increasing the capacity. However, in a process of preparing the large-area electrode, performance of the electrode may be degraded, and there is concern about thermal propagation due to thermal runaway to other electrodes in case of fire. In a lithium secondary battery, a phenomenon may occur in which a temperature of an electrode is rapidly increased due to thermal and physical factors. The thermal factors include overcharging or overload due to misuse or malfunction of a charger, and, as the physical factors, the phenomenon of the rapid increase in the temperature of the electrode may occur when an internal short circuit occurs due to a contact between negative electrode and positive electrode materials which is caused by damage of a separator due to external impact. If the temperature of the electrode is rapidly increased in this way, the battery becomes very unstable due to a reaction between an electrolyte solution and lithium or generation of hydrogen and oxygen in the battery, a solvent of an electrolyte is decomposed to generate gas, and the decomposition gas of the solvent may ignite and lead to an explosion of the battery. A conventional lithium secondary battery includes only a single metal layer as an electrode current collector, wherein, specifically, an aluminum single metal layer has been used as a positive electrode current collector, and a copper single metal layer has been used as a negative electrode current collector. However, since these single metal layers have very high electrical conductivity and thermal conductivity, time to reach a high temperature instantaneously due to abnormal behavior of the battery is very short and there is a concern about thermal propagation due to thermal runaway. Thus, since a weight reduction in comparison to an electrode current collector formed of metal is possible by using an electrode current collector including a polymer resin layer that is disposed between two metal layers, instead of the conventional electrode current collector, energy density per weight may be significantly improved and safety may be improved by causing a short circuit between electrodes in case of fire. However, with respect to the electrode current collector including the polymer resin layer that is disposed between the two metal layers, mechanical safety against foreign matter, for example, nail penetration may be improved, but there is a need to improve safety against thermal propagation in case of actual fire. DISCLOSURE OF THE INVENTION TECHNICAL PROBLEM An aspect of the present invention provides an electrode current collector which may not only have excellent fire safety, heat resistance, and heat shielding effect, but may also be light-weighted to improve energy density, and an electrode assembly and a lithium secondary battery which include the same. TECHNICAL SOLUTION The present invention provides an electrode current collector in order to solve the above-described tasks. [1] The present invention provides an electrode current collector including a polymer resin layer; a first metal layer disposed on one surface of the polymer resin layer; and a second metal layer disposed on another surface of the polymer resin layer, wherein the first metal layer and the second metal layer include a shape memory alloy (SMA), and the shape memory alloy (SMA) is designed such that an external force is applied to the polymer resin layer through shape deformation when a temperature of the shape memory alloy (SMA) is greater than a predetermined temperature.[2] The present invention provides the electrode current collector of [1] above, wherein the shape memory alloy (SMA) includes at least one of a copper-zinc alloy, a copper-tin alloy, a magnesium-copper alloy, a nickel-titanium alloy, and a copper-aluminum-nickel alloy.[3] The present invention provides the electrode current collector of any one or more of [1] or [2] above, wherein an amount of the shape memory alloy (SMA) is in a range of 20 wt% to 100 wt% based on a total weight of the metal layer.[4] The present invention provides the electrode current collector of any one or mo