Secondary batteries, battery packs, and electronic devices

Abstract

The present invention provides a secondary battery, battery pack, and electronic device that can at least improve the yield rate and reduce production costs. [Solution] The present invention provides a secondary battery, a battery pack, and an electronic device. The secondary battery includes a case and an electrode assembly housed within the case, the electrode assembly being formed by laminating a first electrode plate, a separator, and a second electrode plate, the first electrode plate including a first current collector, a conductive layer and an insulating layer covering a portion of at least one surface of the first current collector in a predetermined direction, a first active material layer covering the conductive layer, the first active material layer at least partially covering the insulating layer, and where the thickness of the conductive layer is m and the thickness of the insulating layer is n, n ≤ m.

Claims

1. The case and The electrode assembly housed in the aforementioned case, Includes, The electrode assembly is formed by stacking a first electrode plate, a separator, and a second electrode plate. The first electrode plate includes a first current collector, and a conductive layer and an insulating layer are covered on a portion of at least one surface of the first current collector along a predetermined direction, wherein the predetermined direction is the length direction or the width direction of the first current collector. A first active material layer covers the conductive layer, and the first active material layer at least partially covers the insulating layer, and the orthographic projection of the insulating layer in the thickness direction of the first current collector is at least partially located other than the outer edge of the first active material layer. A secondary battery characterized in that, where the thickness of the conductive layer is m and the thickness of the insulating layer is n, n ≤ m.

2. The secondary battery according to claim 1, characterized in that 0.5 μm ≤ m < 1 μm.

3. The insulating layer comprises an inorganic insulating filler and a binder. Based on the mass of the insulating layer, the mass occupancy of the inorganic insulating filler is 70% to 90%, and the mass occupancy of the binder is 10% to 30%. If D50 is the particle size corresponding to the point when the cumulative particle size distribution volume percentage of the inorganic insulating filler reaches 50%, then the relationship between D50 and n of the inorganic insulating filler satisfies 2 ≤ n / D50 ≤ 5, and / or The secondary battery according to claim 2, characterized in that, when the cumulative particle size distribution volume percentage of the inorganic insulating filler reaches 90%, the particle size corresponding to that is D90, then the D90 of the inorganic insulating filler is less than 0.8 μm.

4. Along the predetermined direction, the insulating layer includes a first region not covered by the first active material layer and a second region covered by the first active material layer, the width of the first region being w1 and the width of the second region being w2. However, 3 mm ≤ w1 + w2 ≤ 20 mm, or The secondary battery according to claim 1, characterized in that 0.1 ≤ w1 / (w1 + w2) ≤ 1.

5. Along the predetermined direction, the first active material layer includes adjacent flat portions and thin portions, and the width of the thin portion is w3. The secondary battery according to claim 4, characterized in that 0 < w2 / w3 ≤ 1.

05.

6. The secondary battery according to claim 1, characterized in that the minimum distance between the insulating layer and the conductive layer along the predetermined direction is w4, provided that 0 ≤ w4 ≤ 1 mm.

7. The first electrode plate is a positive electrode plate, the first active material layer contains lithium iron phosphate, and / or The secondary battery further includes a cover plate assembly, the cover plate assembly covers the case and together with the case defines a housing cavity, the electrode assembly is housed within the housing cavity, and / or The aforementioned secondary battery is a prismatic battery, and / or, The secondary battery according to any one of claims 1 to 6, characterized in that the electrode assembly is a wound electrode assembly.

8. The case includes an annular side wall and an opening formed at one end of the side wall, the case further includes a crimping portion, the crimping portion is formed at one end of the side wall near the opening and is recessed toward the interior of the case, The aforementioned secondary battery is A cover plate attached to the opening, An insulating sealing component is provided on the periphery of the cover plate for insulating and sealing the cover plate and the case, The present invention further includes a current collector plate, which is placed between the electrode assembly and the cover plate and is electrically connected to the case, The connecting piece of the current collector plate is located on the side of the crimping portion facing the electrode assembly and is welded to the crimping portion. and / or, The secondary battery according to any one of claims 1 to 6, characterized in that the secondary battery is a cylindrical battery.

9. A battery pack characterized by including the secondary battery described in claim 1.

10. An electronic device characterized by including the battery pack described in claim 9.

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