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EP-4742314-A1 - ELECTRODE ASSEMBLY AND RECHARGEABLE BATTERY WITH THE SAME

EP4742314A1EP 4742314 A1EP4742314 A1EP 4742314A1EP-4742314-A1

Abstract

An electrode assembly includes a separator, a positive electrode and a negative electrode positioned with the separator therebetween and wound together with the separator. The negative electrode includes a negative substrate, a first active material layer positioned on a first surface of the negative substrate, and a second active material layer positioned on a second surface of the negative substrate. A plurality of first grooves are formed in the first active material layer. A plurality of second grooves having a different pattern from the plurality of first grooves are formed in the second active material layer.

Inventors

  • MIN, JUNGKI
  • HONG, DAEHYUN
  • JI, Hyeongmin

Assignees

  • SAMSUNG SDI CO., LTD.

Dates

Publication Date
20260513
Application Date
20251104

Claims (15)

  1. An electrode assembly, comprising: a separator (30); and a positive electrode (10) and a negative electrode (20) positioned with the separator (30) therebetween and wound together with the separator (30), wherein the negative electrode (20) includes a negative substrate (21), a first active material layer (22) positioned on a first surface of the negative substrate (21), and a second active material layer (23) positioned on a second surface of the negative substrate (21), a plurality of first grooves (51) are formed in the first active material layer (22), and a plurality of second grooves (52) having a different pattern from the plurality of first grooves (51) are formed in the second active material layer (23).
  2. The electrode assembly as claimed in claim 1, wherein: the first surface faces the inside of the electrode assembly, and the plurality of first grooves (51) are positioned in a dot pattern.
  3. The electrode assembly as claimed in claim 2, wherein: the plurality of first grooves (51) are positioned in a circular dot pattern, and one or more of the plurality of first grooves (51) has a width that becomes smaller as a distance thereof from the negative substrate decreases.
  4. The electrode assembly as claimed in claim 2 or 3, wherein: the width of one or more of the plurality of first grooves (51) is in a range of approximately 20 µm to 60 µm, the depth of one or more of the plurality of first grooves (51) is in a range of approximately 30 µm to 70 µm, and the density of the plurality of first grooves (51) is in a range of approximately 100 EA/mm 2 to 450 EA/mm 2 .
  5. The electrode assembly as claimed in any one of the preceding claims, wherein: the second surface faces the outside of the electrode assembly, and the plurality of second grooves (52) are positioned in a line pattern.
  6. The electrode assembly as claimed in claim 5, wherein the plurality of second grooves (52) are positioned parallel to the width direction of the negative electrode (20) and at a distance from each other in the length direction of the negative electrode (20).
  7. The electrode assembly as claimed in claim 5 or 6, wherein: the width of one or more of the plurality of second grooves (52) is greater than the depth thereof, and one or more of the plurality of second grooves (52) has a substantially constant width in the thickness direction of the negative electrode (20).
  8. The electrode assembly as claimed in any one of the claims 5 to 7, wherein: the width of one or more of the plurality of second grooves (52) is in a range of approximately 40 µm to 70 µm, and the depth of one or more of the plurality of second grooves (52) is in a range of approximately 10 µm to 30 µm.
  9. An electrode assembly, comprising: a separator (30); and a positive electrode (10) and a negative electrode (20) positioned with the separator (30) therebetween and wound together with the separator (30), wherein the negative electrode (20) includes a negative substrate (21), a first active material layer (22) positioned on the inner surface of the negative substrate (21), and a second active material layer (23) positioned on the outer surface of the negative substrate (21), a plurality of first grooves (51) are formed in the first active material layer (22), a plurality of second grooves (52) having a different pattern from the plurality of first grooves (51) are formed in the second active material layer (23), and the surface area exposed by the plurality of second grooves (52) in the second active material layer (23) is larger than the surface area exposed by the plurality of first grooves (51) in the first active material layer (22).
  10. The electrode assembly as claimed in claim 9, wherein: the plurality of first grooves (51) are positioned in a dot pattern, and the plurality of second grooves (52) are positioned in a line pattern.
  11. The electrode assembly as claimed in claim 10, wherein the plurality of second grooves (52) are positioned in a line pattern parallel to the width direction of the negative electrode (20), and are spaced apart from each other in the length direction of the negative electrode (20).
  12. The electrode assembly as claimed in any one the claims 1 to 11, wherein: the negative electrode (20) comprises a flat portion and a bent portion (42), and the plurality of first grooves (51) and the plurality of second grooves (52) are positioned at least in the bent portion (42).
  13. The electrode assembly as claimed in claim 12, wherein the plurality of first grooves (51) and the plurality of second grooves (52) are positioned throughout the flat portion and the bent portion (42).
  14. A rechargeable battery, comprising: the electrode assembly according to any one of the claims 1 to 13; and a case (120) configured to accommodate and seal the electrode assembly and electrolyte in an internal space.
  15. The rechargeable battery as claimed in claim 14, wherein: the electrode assembly is wound around two rotation axes and comprises a central portion (41) and a pair of bent portions (42) positioned on both sides of the central portion (41), and the plurality of first grooves (51) and the plurality of second grooves (52) are positioned at least at one pair of bent portions (42).

Description

BACKGROUND OF THE DISCLOSURE (a) Field of the Disclosure The present disclosure relates to a rechargeable battery, and to a rechargeable battery having a wound-type electrode assembly. (b) Description of the Related Art Rechargeable batteries are used for a variety of purposes, including as a power source for small electronic devices such as, e.g., mobile phones and laptop computers, and as a power source for driving, e.g., motors of electric vehicles and hybrid vehicles. A rechargeable battery includes an electrode assembly and a case that accommodates and seals the electrode assembly and electrolyte in an internal space. The electrode assembly includes two electrodes (positive electrode and negative electrode) and a separator. In order to increase the output and capacity of rechargeable batteries, increasing the energy density and loading level of electrodes may be advantageous. However, electrodes developed in this way may have the unintended side effect of reducing the impregnability of the electrolyte. When the impregnability of the electrolyte in the electrode decreases, precipitation may begin in areas where the impregnability of the electrolyte is insufficient, which may reduce the life characteristics of the rechargeable battery. SUMMARY The present disclosure describes an electrode assembly and a rechargeable battery including the electrode assembly and capable of improving life characteristics by increasing the energy density and loading level of an electrode while improving the impregnability of an electrolyte. An electrode assembly according to an aspect includes a separator, a positive electrode and a negative electrode positioned with the separator therebetween and wound together with the separator. The negative electrode includes a negative substrate, a first active material layer positioned on a first surface of the negative substrate, and a second active material layer positioned on a second surface of the negative substrate. A plurality of first grooves are formed in the first active material layer. A plurality of second grooves having a different pattern from the plurality of first grooves are formed in the second active material layer. The first surface may face the inside of the electrode assembly, and the plurality of first grooves may be provided in a dot pattern. The plurality of first grooves may be provided in a circular dot pattern, and each of, or one or more of, the plurality of first grooves may have a width that becomes smaller as distance thereof from the negative substrate decreases. The width of each of, or one or more of, the plurality of first grooves may be in a range of approximately 20 µm to 60 µm. The depth of each of, or one or more of, the plurality of first grooves may be in a range of approximately 30 µm to 70 µm. The density of the plurality of first grooves may be in a range of approximately 100 EA/mm2 to 450 EA/mm2. The second surface may face the outside of the electrode assembly, and the plurality of second grooves may be positioned in a line pattern. The plurality of second grooves may be positioned parallel to the width direction of the negative electrode and spaced apart from each other in the length direction of the negative electrode. The width of each of, or one or more of, the plurality of second grooves may be greater than the depth of each of, or one or more of, the plurality of second grooves. Each of, or one or more of, the plurality of second grooves may have a constant width, or a substantially constant width, in the thickness direction of the negative electrode. The width of each of, or one or more of, the plurality of second grooves may be in a range of approximately 40 µm to 70 µm. The depth of each of, or one or more of, the plurality of second grooves may be in a range of approximately 10 µm to 30 µm. An electrode assembly according to another aspect includes a separator, and a positive electrode and a negative electrode positioned with the separator therebetween and wound together with the separator. The negative electrode includes a negative substrate, a first active material layer positioned on the inner surface of the negative substrate, and a second active material layer positioned on the outer surface of the negative substrate. The plurality of first grooves are formed in the first active material layer. The plurality of second grooves having a different pattern from the plurality of first grooves are formed in the second active material layer. The surface area exposed by the plurality of second grooves in the second active material layer is larger than the surface area exposed by the plurality of first grooves in the first active material layer. The plurality of first grooves may be positioned in a dot pattern, and the second plurality of grooves may be positioned in a line pattern. The plurality of first grooves may be positioned in a circular dot pattern, and each of, or one or more of, the plurality of first grooves may have a wid