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CN-122025530-A - Pole piece, manufacturing method thereof, secondary battery and power utilization device

CN122025530ACN 122025530 ACN122025530 ACN 122025530ACN-122025530-A

Abstract

The application discloses a pole piece, a manufacturing method thereof, a secondary battery and an electric device, wherein the pole piece comprises a current collector, an active material layer, a conductive member and an insulating layer, the current collector comprises a first part and a second part which are adjacently arranged along a first direction, the active material layer is arranged on the first part, the active material layer comprises a first covering part and a second covering part which are sequentially arranged along the first direction, the thickness of the second covering part is smaller than that of the first covering part along the thickness direction of the current collector, the conductive member is connected to the second part, and the insulating layer is arranged on the second part, at least part of the conductive member is far away from the surface of the current collector and at least part of the second covering part is far away from the surface of the current collector. Compared with the existing pole piece, the pole piece with the structure can reduce the risk of thicker thickness at the edge of the active material layer caused by the fact that the insulating layer is coated on the active material layer in the manufacturing process, and is beneficial to improving the energy density of the secondary battery.

Inventors

  • YAN JIAXIAO
  • QU CHANGMING

Assignees

  • 宁德新能源科技有限公司

Dates

Publication Date
20260512
Application Date
20240510

Claims (16)

  1. 1. A pole piece, comprising: A current collector including a first portion and a second portion disposed adjacently along a first direction; An active material layer disposed on the first portion, the active material layer including a first cover portion and a second cover portion disposed in the first direction, the second cover portion having a thickness smaller than a thickness of the first cover portion in a thickness direction of the current collector; A conductive member connected to the second portion; and the insulating layer is arranged on the surface of the second part and at least part of the second covering part, which is far away from the current collector, and the first direction is perpendicular to the thickness direction of the current collector.
  2. 2. The pole piece of claim 1, wherein a difference between a thickness of the first covering portion and a thickness of the second covering portion along a thickness direction of the current collector is t 1 , satisfying 10 μm < t 1 ∈50 μm.
  3. 3. The pole piece of claim 1, wherein the second cover has a width d 1 along the first direction that satisfies 1mm < d 1 ∈2mm.
  4. 4. A pole piece according to claim 3, characterized in that 1mm < d 1 < 1.5mm.
  5. 5. The pole piece of claim 1, wherein the insulating layer comprises a first insulating portion overlapping the first cover portion, the first insulating portion having a width d 2 along the first direction that satisfies 0.1mm < d 2 +.1.6 mm.
  6. 6. The pole piece of claim 5, wherein 0.1mm < d 2 is less than or equal to 1mm.
  7. 7. The pole piece of claim 1, wherein the insulating layer comprises a first insulating portion, a second insulating portion, and a third insulating portion, the first insulating portion, the second insulating portion, and the third insulating portion being sequentially disposed along the first direction, the first insulating portion overlapping the first covering portion, the third insulating portion covering a surface of the conductive member facing away from the current collector, the second insulating portion having a thickness t 2 in a thickness direction of the current collector, the thickness t 2 being 10 μm < 50 μm; And/or, in the first direction, the insulating layer has a width d 3 , satisfying 1.2mm < d 3 <5mm.
  8. 8. The pole piece of claim 1, wherein the conductive member and the second portion are connected by roll welding and form a weld, the weld having a dimension d 4 in the first direction that satisfies 1mm < d 4 <5mm.
  9. 9. A pole piece according to claim 1, characterized in that at least part of the surface of the conductive member remote from the current collector is provided with the insulating layer comprising an inorganic ceramic or a non-conductive organic polymer layer.
  10. 10. The pole piece of any of claims 1-9, further comprising an undercoat layer disposed between the first portion and the active material layer in a thickness direction of the current collector.
  11. 11. The pole piece of claim 10, wherein the active material layer comprises a first active material layer and a second active material layer, the primer layer comprising a first primer layer and a second primer layer; The current collector comprises a base layer, a first conductive layer and a second conductive layer, wherein the first conductive layer is arranged on one surface of the base layer, the second conductive layer is arranged on the other surface of the base layer, a first base coat and a first active material layer are sequentially arranged on one end face, deviating from the base layer, of the first conductive layer, a second base coat and a second active material layer are sequentially arranged on one end face, deviating from the base layer, of the second conductive layer, and the base layer is a high polymer layer.
  12. 12. The pole piece of claim 11, wherein the conductive member comprises a first conductive member and a second conductive member, the first conductive member being connected to the first conductive layer and the second conductive member being connected to the second conductive layer.
  13. 13. A secondary battery comprising a pole piece according to any one of claims 1-12.
  14. 14. An electric device comprising the secondary battery according to claim 13.
  15. 15. A method of manufacturing a pole piece for use in the manufacture of a pole piece according to any one of claims 1 to 12, the method comprising: Providing the current collector and a conductive piece, wherein the current collector comprises a coated area and an uncoated area; Coating an active material on a coating region of the current collector and forming an active material layer, wherein the active material layer comprises a first covering part and a second covering part, and the thickness of the first covering part is unequal; Step three, the conductive piece is connected to an uncoated area of the current collector in a conductive way; And fourthly, coating an insulating material on the surface of the second part, at least part of the conductive piece far away from the current collector and at least part of the second covering part far away from the current collector to form the insulating layer.
  16. 16. The method of manufacturing a pole piece of claim 15, wherein the conductive member is attached to the uncoated region of the current collector by roll welding.

Description

Pole piece, manufacturing method thereof, secondary battery and power utilization device Technical Field The embodiment of the invention relates to the field of secondary batteries, in particular to a pole piece, a manufacturing method thereof, a secondary battery and an electric device. Background A secondary battery is a device capable of repeatedly charging and discharging, and is generally composed of a case, an electrode assembly provided in the case, and a tab connected to the electrode assembly, the tab being connectable to an electric device. The electrode assembly comprises pole pieces with different polarities and isolating films, the isolating films are arranged between two adjacent pole pieces with different polarities, each pole piece comprises a current collector and an active substance layer arranged on the surface of the current collector, and the current collector can be a conventional current collector or a composite current collector. At present, the space for installing the secondary battery by the electric equipment is limited, and in the set space, the higher the capacity of the secondary battery is, the more favorable for the cruising of the electric device, so that the improvement of the energy density of the secondary battery is more and more important. Disclosure of Invention In order to solve the technical problems, the embodiment of the application provides a pole piece, a secondary battery and an electricity utilization device, wherein the pole piece, the secondary battery and the electricity utilization device can improve energy density in the thickness direction. The technical scheme adopted by the embodiment of the application for solving the technical problems is as follows: the pole piece comprises a current collector, an active material layer, a conductive piece and an insulating layer, wherein the current collector comprises a first part and a second part which are adjacently arranged along a first direction, the active material layer is arranged on the first part, the active material layer comprises a first covering part and a second covering part which are sequentially arranged along the first direction, the thickness of the second covering part is smaller than that of the first covering part along the thickness direction of the current collector, the conductive piece is connected to the second part, the insulating layer is arranged on the second part, at least part of the conductive piece is far away from the surface of the current collector and at least part of the second covering part is far away from the surface of the current collector, and the first direction is perpendicular to the thickness direction of the current collector. Thus, when the insulating layer covers the active material layer, the space obtained by the thickness difference between the second cover part and the first cover part in the active material layer can be utilized, the thickness of the overlapping part of the insulating layer and the active material layer is reduced, the risk of thicker thickness of the overlapping part of the active material layer and the insulating layer caused by the application of the insulating layer to the edge of the active material layer is reduced, and the energy density of the secondary battery is improved. Meanwhile, the insulating layer can reduce the exposed risk of burrs of the conductive piece and burrs of the second part, the risk of pole piece short circuit caused by the fact that the secondary battery manufactured by the pole piece pierces the isolating film due to the burrs is reduced, and the safety of the secondary battery is improved. Optionally, along the thickness direction of the current collector, the difference between the thickness of the first covering portion and the thickness of the second covering portion is t 1, satisfying 10 μm < t 1≤50 μm. When t 1 is less than 10 mu m, the risk that the thickness of the part is thicker exists when the insulating layer covers the second covering part, the insulating layer is coated when t1 is more than 50 mu m, the smaller the supporting force of the conductive piece is, the conductive piece is easy to droop, and the region where the conductive piece is located is easy to crumple and fold when the pole piece is rolled or released in the manufacturing process. When the thickness of the pole piece is more than 10 mu m and less than or equal to 50 mu m, the thickness of the pole piece at the second covering part is more suitable, the risk of wrinkling and folding when the pole piece is rolled or released in the manufacturing process is reduced, and the risk of reducing the capacity of the secondary battery caused by the loss of active substances is reduced. Optionally, the width of the second cover portion is d 1 along the first direction, satisfying 1mm < d 1 +.2 mm. In this way, the width of the second covering portion in the first direction is suitable, and since the area of the second covering portion of t