Pole piece and preparation method and application thereof

Abstract

The present invention provides a pole piece and a preparation method and application thereof, the pole piece comprises: a current collector, the current collector comprises a coated region and an uncoated region, the coated region comprises an active material layer, a first insulation part and a second insulation part which are arranged along a preset direction on at least one surface of the current collector in the thickness direction and are sequentially and adjacently arranged; in the thickness direction of the current collector, the thickness of the first insulating part is greater than that of the second insulating part; the first insulating part comprises a first insulating layer and a second insulating layer coated on the first insulating layer; and the bottom coating layer is arranged between the active material layer and the current collector, and a preset distance exists between the bottom coating layer and the first insulating layer. According to the pole piece as well as the preparation method and the application thereof, mutual dissolution of the first insulation part and the active substance layer can be avoided on the premise of reducing wrinkles and folding of the uncoated area.

Claims

1. A pole piece, characterized in that: include: a current collector, the current collector comprising a coated region and an uncoated region, the coated region comprising an active material layer, a first insulating portion, and a second insulating portion disposed in sequence and adjacent to each other along a predetermined direction and disposed on at least one side of the current collector in a thickness direction; the first insulating portion being thicker than the second insulating portion in the thickness direction of the current collector; The first insulating portion includes a first insulating layer and a second insulating layer coated on the first insulating layer; A primer layer is disposed between the active material layer and the current collector, and a preset distance exists between the primer layer and the first insulating layer.

2. The pole piece according to claim 1, characterized in that: Along the preset direction, the second insulating portion and the first insulating layer are obtained by coating the same slurry at one time.

3. The pole piece according to claim 1, characterized in that: Along the preset direction, the preset spacing is G mm, the width of the first insulating portion is W1 mm, and 2≤W1 / G≤10 is satisfied; or, The value range of G is 0.5mm-4mm.

4. The pole piece according to claim 3, characterized in that: Along the preset direction, the width of the second insulating portion is W2 mm, the width of the uncoated area is W3 mm, and 1.5≤W3 / W1≤10, 1.6≤W3 / W2≤25 is satisfied; or, The value range of W3 is 9mm-36mm.

5. The pole piece according to claim 1, characterized in that: Along the preset direction, one end of the active material layer exceeds the base coating layer, and the exceeding width is smaller than the preset distance.

6. The pole piece according to claim 1, characterized in that: The first insulating layer includes a first binder and an inorganic insulating material, wherein the first binder includes at least one of polyacrylic acid, styrene-butadiene rubber, polyvinyl alcohol, polyacrylamide, methyl cellulose and salts thereof, chitosan and salts thereof, and alginic acid and salts thereof.

7. The pole piece according to claim 1, characterized in that: The second insulating layer includes a second binder and an inorganic insulating material, the second binder includes at least one of polyvinylidene fluoride or oily polyimide, and the oily polyimide includes at least one of homophenyl polyimide or biphenyl / ether anhydride polyimide; And / or, the median particle size of the inorganic insulating material in the second insulating layer is smaller than the median particle size of the inorganic insulating material in the first insulating layer.

8. The pole piece according to claim 1, characterized in that: The active material layer includes an active material, a third binder and a conductive agent, the third binder includes at least one of polyvinylidene fluoride, oily polyimide, polyvinylidene fluoride-hexafluoropropylene or polytetrafluoroethylene, and the oily polyimide includes at least one of homophenyl polyimide or biphenyl / ether anhydride polyimide.

9. The pole piece according to claim 1, characterized in that: The pole piece also includes a pole ear, which protrudes from the current collector body along the preset direction. The current collector body includes the active material layer covering area and a transition zone located between the active material layer and the pole ear. The transition zone extends from one end of the current collector to the other end perpendicular to the preset direction. The second insulating portion and part of the first insulating portion are located on the surface of the pole ear, and another part of the first insulating portion is located in the transition zone.

10. A method for preparing a pole piece, characterized in that: include: Pre-forming a first insulating layer and a primer layer arranged along a preset direction on at least one side of the current collector at a preset interval; The second binder and the inorganic insulating material are prepared into an insulating paste according to a mass ratio; The active material, the third binder and the conductive agent are prepared into an active slurry according to a mass ratio; The active slurry and the insulating slurry are simultaneously coated on the primer layer, the preset distance and a portion of the first insulating layer to obtain an active material layer and a second insulating layer; the active material layer and the second insulating layer are adjacently arranged, and the second insulating layer covers a portion of the preset distance and a portion of the first insulating layer.

11. A battery, characterized in that: At least: A shell having an upper opening; an electrode assembly disposed within the housing; as well as A cover plate assembly with a sealed upper opening, the cover plate assembly comprising a transition piece, wherein the width direction of the transition piece comprises a first tab welding portion and a second tab welding portion symmetrically arranged along the length direction of the transition piece; The electrode assembly is formed by stacking a positive electrode sheet, a separator, and a negative electrode sheet, and then winding or laminating them. The positive electrode sheet is the electrode sheet according to any one of claims 1 to 9 or the electrode sheet obtained by the preparation method according to claim 10. Along a preset direction, the electrode assembly includes a main body and a tab. The tab includes an uncoated area and a second insulating portion and a portion of the first insulating portion provided on the same side of the tab in the thickness direction. There are two groups of electrode assemblies. The tabs of one group of electrode assemblies and the tabs of the other group of electrode assemblies are bent relative to each other and then welded to the first tab welding portion and the second tab welding portion of the adapter sheet respectively.

12. The battery according to claim 11, characterized in that The electrode assembly includes a first tape, which is arranged on the side of the tab facing away from the cover plate assembly. The first tape includes a first adhesive area, a second adhesive area, and a non-adhesive area between the first adhesive area and the second adhesive area. The first adhesive area covers the main body, and the second adhesive area covers the uncoated area. In the thickness direction of the electrode assembly, the orthographic projections of the first insulating part and the second insulating part are completely located in the non-adhesive area.

13. An electronic device, characterized in that: A battery comprising the battery according to any one of claims 11 to 12.

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