Search

KR-20260065068-A - LITHIUM SECONDARY BATTERY

KR20260065068AKR 20260065068 AKR20260065068 AKR 20260065068AKR-20260065068-A

Abstract

A lithium secondary battery according to the present invention comprises a positive electrode; a negative electrode; a separator; and an electrolyte; and (DCIR_SOC5*DCIR_SOC20*DCIR_SOC50)/((DCIR_SOC10) 2 ) may satisfy a specific range.

Inventors

  • 김현진
  • 신동민
  • 이기승
  • 김완주
  • 박혜원
  • 김득수

Assignees

  • (주)포스코퓨처엠

Dates

Publication Date
20260508
Application Date
20241031

Claims (11)

  1. It includes an anode; a cathode; a separator; and an electrolyte, That which satisfies Equation 1 below, Lithium secondary battery: [Equation 1] 1.710Ω < (DCIR_SOC5*DCIR_SOC20*DCIR_SOC50)/((DCIR_SOC10) 2 ) < 2.250Ω (In Equation 1, The above DCIR_SOC5 refers to the DC internal resistance measured after setting the SOC (State Of Charge) to 5, and The above DCIR_SOC10 refers to the DC internal resistance measured after setting to SOC10, and The above DCIR_SOC20 refers to the DC internal resistance measured after setting to SOC20, and The above DCIR_SOC50 refers to the DC internal resistance measured after setting to SOC50.
  2. In paragraph 1, The above DCIR_SOC5 is in the range of 2.30 to 4.10Ω, Lithium secondary battery.
  3. In paragraph 1, The above DCIR_SOC10 is in the range of 1.70 to 2.50 Ω, Lithium secondary battery.
  4. In paragraph 1, The above DCIR_SOC20 is in the range of 1.40 to 2.00 Ω, Lithium secondary battery.
  5. In paragraph 1, The above DCIR_SOC50 is in the range of 1.30 to 1.90 Ω, Lithium secondary battery.
  6. In paragraph 1, The above lithium secondary battery is one in which the State of Charge (SOC) is set to 20% and the low-temperature output measured at -10℃ is 125.0 seconds or longer, Lithium secondary battery.
  7. In paragraph 6, The above low-temperature output is measured as the time to reach 2.0V by applying a constant output of 0.112W, Lithium secondary battery.
  8. In paragraph 1, The above anode is one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof, Lithium secondary battery.
  9. In paragraph 1, The positive active material included in the above lithium secondary battery is represented by the following chemical formula 1, Lithium secondary battery: [Chemical Formula 1] Li a [Ni x Co y Mn z M w ]O 2 In the above chemical formula 1, 0.8≤a≤1.2, 0.8≤x<1.0, 0<y≤0.1, 0<z≤0.1, 0≤w≤0.1, x+y+z+w=1, and M is one or more elements selected from the group consisting of Al, Zr, Y, B, Mg, Ti, Nb, W, Sc, Si, P, V, Fe, Mo, Ce, Hf, Ta, La and Sr.
  10. In paragraph 1, The above-mentioned cathode comprises one or more cathode active materials selected from the group consisting of artificial graphite, natural graphite, graphitized carbon fiber, amorphous carbon, Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, Al alloy, SiO β (0 < β ≤ 2), SnO 2 , vanadium oxide, lithium vanadium oxide, Si-C composite, Sn-C composite, and metallic lithium thin film. Lithium secondary battery.
  11. In paragraph 1, The separator is one or more selected from the group consisting of ethylene homopolymer, propylene homopolymer, ethylene/butene copolymer, ethylene/hexene copolymer and ethylene/methacrylate copolymer, high melting point glass fiber, and polyethylene terephthalate fiber. Lithium secondary battery.

Description

Lithium Secondary Battery These embodiments relate to lithium secondary batteries. Driven by the recent explosive demand for electric vehicles and the need for increased driving range, there is a demand for the development of lithium-ion batteries that possess high capacity and high energy density to meet these requirements, while simultaneously exhibiting stable output characteristics even in low-temperature environments. A lithium secondary battery generally consists of a positive electrode, a negative electrode, a separator, and an electrolyte, and the positive and negative electrodes include an active material capable of lithium ion intercalation and deintercalation. Lithium secondary batteries operate through the movement of electrons caused by the diffusion of lithium ions between the positive and negative electrodes via an electrolyte. However, when the external temperature drops below freezing, the temperature of the electrolyte inside the battery decreases, slowing down the diffusion rate of lithium ions. Consequently, the energy efficiency of the lithium secondary battery decreases, leading to a problem of reduced output. Accordingly, there is a need to develop lithium secondary batteries capable of solving the problem of reduced output at low temperatures. Terms such as first, second, and third are used to describe various parts, components, regions, layers, and/or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention. The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and/or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and/or components. When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined. Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %. In this specification, the term “combination(s) of these” described in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including any one or more selected from the group consisting of said components. Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. lithium secondary battery A lithium secondary battery according to one embodiment comprises a positive electrode; a negative electrode; a separator; and an electrolyte; and may satisfy the following formula 1. [Equation 1] 1.710Ω < (DCIR_SOC5*DCIR_SOC20*DCIR_SOC50)/((DCIR_SOC10) 2 ) < 2.250 Ω (In Equation 1, The above DCIR_SOC5 refers to the DC internal resistance measured after setting the SOC (State Of Charge) to 5, and The above DCIR_SOC10 refers to the DC internal resistance measured after setting to SOC10, and The above DCIR_SOC20 refers to the DC internal resistance measured after setting to SOC20, and The above DCIR_SOC50 refers to the DC internal resistance measured after setting to SOC50. More specifically, the above DC internal resistance may be measured as ‘(voltage before current application - voltage after current application for 60 seconds) / applied current’ after measuring the voltage value after applying a discharge current in a state charged to 4.2V. The above (DCIR_SOC5*DCIR_SOC20*DCIR_SOC50)/((DCIR_SOC10) 2 ) may be in the range of 1.710 to 2.250 Ω, preferably 1.710 Ω to 2.000 Ω, 1.710 Ω to 1.950 Ω, 1.715 Ω to 1.900 Ω, 1.720 to 1.880 Ω, 1.725 to 1.860 Ω, 1.730 to 1.840 Ω, 1.735 to 1.820 Ω, or 1.740 to 1.800 Ω. If the value exceeds or falls belo