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EP-4525127-B1 - ELECTRODE ASSEMBLY AND BATTERY

EP4525127B1EP 4525127 B1EP4525127 B1EP 4525127B1EP-4525127-B1

Inventors

  • BAI, YAN
  • ZHU, Xiuzhen
  • YANG, Changjian

Dates

Publication Date
20260506
Application Date
20231031

Claims (14)

  1. An electrode assembly, comprising a positive electrode piece, a separator and a negative electrode piece that are laminated in sequence and formed by winding, wherein the positive electrode piece comprises a positive electrode current collector (101) and a positive electrode tab (300), and the positive electrode tab (300) is divided into a first region (c) and a second region (d), with the first region (c) being connected to the positive electrode current collector (101) and the second region (d) extending outward from the first region (c) along a width direction of the positive electrode current collector (101) to an exterior of the positive electrode current collector (101); characterized in that the electrode assembly further comprising a first protective layer (500), wherein the first protective layer (500) has several holes to allow ions to pass through two surfaces of the first protective layer (500) that are parallel to each other; the first protective layer (500) is arranged on surfaces of the positive electrode piece and the negative electrode piece, and in a projection plane based on a length direction and a width direction of the electrode assembly, an orthographic projection of the first protective layer (500) in the projection plane covers an orthographic projection of the first region (c) in the projection plane.
  2. The electrode assembly according to claim 1, wherein the negative electrode piece comprises a negative electrode current collector (201) and a negative electrode tab (400) which is divided into a third region (g) and a fourth region (h), with the third region (g) being connected to the negative electrode current collector (201) and the fourth region (h) extending outward from the third region (g) along a width direction of the negative electrode current collector (201) to an exterior of the negative electrode current collector (201); the electrode assembly further comprising a second protective layer (600) capable of blocking ions from passing through two surfaces of the second protective layer (600) that are parallel to each other, wherein the second protective layer (600) is arranged on the surfaces of the positive electrode piece and the negative electrode piece, and an orthographic projection of the second protective layer (600) in the projection plane covers an orthographic projection of the third region (g) in the projection plane.
  3. The electrode assembly according to claim 2, wherein the orthographic projection of the second protective layer (600) arranged on the surface of the negative electrode piece in the projection plane is a first projection, and the orthographic projection of the second protective layer (600) arranged on the surface of the positive electrode piece in the projection plane is a second projection, with the first projection being located within the second projection.
  4. The electrode assembly according to claim 1, wherein the positive electrode current collector (101) comprises a first surface (a) and a second surface (b) that are parallel and opposite to each other, the first surface (a) is connected to the first region (c) of the positive electrode tab (300), the second surface (b) is provided with a positive electrode active material layer (102), and an orthographic projection of the positive electrode active material layer (102) on the positive electrode current collector (101) covers or does not cover an orthographic projection of the first region (c) on the positive electrode current collector (101); the first protective layer (500) is arranged on a surface of the first region (c) away from the positive electrode current collector (101) and a surface of the positive electrode active material layer (102) away from the positive electrode current collector (101).
  5. The electrode assembly according to claim 4, wherein the negative electrode piece comprises a negative electrode current collector (201) and a negative electrode active material layer (202) arranged on a surface of the negative electrode current collector (201), a surface of the negative electrode active material layer (202) away from the negative electrode current collector (201) is also provided with the first protective layer (500), and the first protective layer (500) arranged on the surface of the negative electrode active material layer (202) is opposite to the first protective layer (500) arranged on the surface of the positive electrode piece.
  6. The electrode assembly according to claim 2, wherein the negative electrode current collector (201) comprises a third surface (e) and a fourth surface (f) that are parallel and opposite to each other, with the third surface (e) being connected to the third region (g) of the negative electrode tab (400) and the fourth surface (f) being provided with a negative electrode active material layer (202), and an orthographic projection of the negative electrode active material layer (202) on the negative electrode current collector (201) does not cover an orthographic projection of the third region (g) on the negative electrode current collector (201); the second protective layer (600) is arranged on a surface of the third region (g) away from the negative electrode current collector (201) and on a surface of the negative electrode active material layer (202) away from the negative electrode current collector (201).
  7. The electrode assembly according to claim 6, wherein the positive electrode piece further comprises a positive electrode active material layer (102) arranged on a surface of the positive electrode current collector (101), and the second protective layer (600) is arranged on a surface of the positive electrode active material layer (102) away from the positive electrode current collector (101), with the second protective layer (600) arranged on the surface of the positive electrode active material layer (102) being opposite to the second protective layer (600) arranged on the surface of the negative electrode piece.
  8. The electrode assembly according to claim 2, wherein the negative electrode current collector (201) comprises a third surface (e) and a fourth surface (f) that are parallel and opposite to each other, with the third surface (e) being connected to the third region (g) of the negative electrode tab (400) and the fourth surface (f) being provided with a negative electrode active material layer (202), and an orthographic projection of the negative electrode active material layer (202) on the negative electrode current collector (201) covers an orthographic projection of the third region (g) on the negative electrode current collector (201); the first protective layer (500) is arranged on a surface of the negative electrode active material layer (202) away from the negative electrode current collector (201), and the second protective layer (600) is arranged on a surface of the third region (g) away from the negative electrode current collector (201).
  9. The electrode assembly according to claim 8, wherein the positive electrode piece further comprises a positive electrode active material layer (102) arranged on a surface of the positive electrode current collector (101), and a surface of the positive electrode active material layer (102) away from the positive electrode current collector (101) is provided with the first protective layer (500) and the second protective layer (600); the first protective layer (500) arranged on the surface of the positive electrode active material layer (102) is opposite to the first protective layer (500) arranged on the surface of the negative electrode piece, and the second protective layer (600) arranged on the surface of the positive electrode active material layer (102) is opposite to the second protective layer (600) arranged on the surface of the negative electrode piece.
  10. The electrode assembly according to any one of claims 1 to 9, wherein the positive electrode piece further comprises a positive electrode active material layer (102) arranged on a surface of the positive electrode current collector (101), and at least part of a surface of the positive electrode active material layer (102) close to a finishing point of winding is provided with a second protective layer (600) capable of blocking ions from passing through two surfaces of the second protective layer (600) that are parallel to each other, and the second protective layer (600) extends toward the finishing point of winding to the at least part of the surface of the positive electrode current collector (101).
  11. The electrode assembly according to any one of claims 1 to 10, wherein the first protective layer (500) comprises a glue layer (602), and the glue layer (602) comprises one of polystyrene, polyisobutylene, polypropylene, epoxidized polyisobutylene, polyphenylbutylene, or polybutylene cyanide.
  12. The electrode assembly according to claim 11, wherein the first protective layer (500) comprises a first glue layer (501) and a second glue layer (502) which are laminated in sequence, and a peel strength of the first glue layer (501) and a peel strength of the second glue layer (502) are the same or different.
  13. A battery, comprising the electrode assembly according to any one of claims 1 to 12.
  14. The battery according to claim 13, wherein the battery is a button battery and further comprises a housing (700) encapsulating the electrode assembly; the housing (700) comprises a first electrode piece (800) and a second electrode piece; and the first protective layer (500) is arranged between the first electrode piece (800) and the second electrode piece.

Description

The present application claims priority to Chinese Patent Application No. 202223267590.3, entitled "ELECTRODE ASSEMBLY AND BATTERY", and filed with the China National Intellectual Property Administration on December 05, 2022. TECHNICAL FIELD The present application relates to an electrode assembly and a battery, and relates to the technical field of batteries. BACKGROUND A battery is a device that can convert chemical energy into electrical energy, which includes an electrode assembly and a housing that encapsulates the electrode assembly. The electrode assembly usually includes a positive electrode piece, a negative electrode piece and a separator. Both the positive electrode piece and the negative electrode piece include an active material. The battery is energized by the electrochemical reaction between the positive active material and the negative active material. The separator is located between the positive electrode piece and the negative electrode piece to prevent the two from contacting and causing a short circuit. The positive electrode piece and the negative electrode piece are respectively connected with tabs to realize the connection between the positive and negative electrode pieces and the external circuit of the battery. In order to prevent the burrs on the tab from piercing the separator and causing a short circuit between the positive electrode piece and the negative electrode piece, the tab is generally provided with a protective layer. However, the commonly used protective layer also blocks the passage of ions, which results in the fact that the portion that the protective layer is attached to fails to undergo electrochemical reactions, affecting the energy of battery. CN115332469A relates to an electrode assembly which addresses the issue of large positional tolerance for protective layers on electrode pieces of different polarities by arranging the protective layer of second electrode piece on the surface of separator away from the first electrode piece and laminating the separator and the first electrode piece together, thereby achieving dual tab protection. WO2021227896A1 relates to a battery and an electronic device. The battery includes a first electrode sheet, a second electrode sheet and an insulation separator, where the insulation separator is located between the first electrode sheet and the second electrode sheet; the first electrode sheet includes a first current collector and a first tab, the first current collector includes a first surface and a second surface, and the first surface and the second surface are each provided with a first active material layer; the first active material layer is provided with a first groove and a second groove which are respectively located on the first surface and the second surface and have opposite positions; the first tab is welded in the first groove; and the first groove is covered with at least one insulation layer, and the second groove is covered with at least one insulation layer. EP3817123A1 relates to an electrode assembly, which includes a positive electrode sheet including a positive electrode active material portion, a positive electrode non-coating portion, and a positive tab arranged on the positive electrode non-coating portion; a negative electrode sheet including a negative electrode active material portion, a negative electrode non-coating portion, and a negative tab arranged on the negative electrode non-coating portion; and a separator configured to insulate the positive electrode sheet and the negative electrode sheet from each other. SUMMARY The present invention is set out in the appended set of claims. The present application provides an electrode assembly, including a positive electrode piece, a negative electrode piece, and a first protective layer arranged on surfaces of the positive electrode piece and the negative electrode piece. The first protective layer has several holes capable of allowing ions to pass through, which can take into account the energy of battery on the basis of protecting the burrs of the tab from piercing the separator. The present application further provides a battery including the above electrode assembly. A first aspect of the present application provides an electrode assembly, including a positive electrode piece and a negative electrode piece that are formed by winding, where the positive electrode piece includes a positive electrode current collector and a positive electrode tab, and the positive electrode tab is divided into a first region and a second region, with the first region being connected to the positive electrode current collector, the second region extending outward from the first region along a width direction of the positive electrode current collector to an exterior of the positive electrode current collector; the electrode assembly further includes a first protective layer, where the first protective layer has several holes to allow ions to pass through two surfaces o