锂离子电池

Abstract

本实用新型提供了一种锂离子电池。锂离子电池包括电芯，电芯包括隔膜和极片，该锂离子电池的群裕度为γ，单位为％，隔膜和极片之间的间距定义为dgap；其中，γ和dgap满足关系式：1μm≤dgap / γ≤3μm。本实用新型在设计隔膜结构时，控制γ和dgap之间的特定比例关系等参数，实现了在电池制造过程中隔膜的精确控制，从而不但可以有效提升电芯的保液浸润能力，还能够避免电芯入壳不良的风险，同时，提高生产的一致性和良率。

Claims

1. A lithium-ion battery comprising a cell, the cell comprising a separator and a pole piece, the lithium-ion battery having a population margin, γ, in percent, characterized in that, The distance between the separator and the pole piece is defined as d gap ; wherein the γ and the d gap satisfy the relationship: 1 μm ≤ d gap / γ ≤ 3 μm.

2. The lithium-ion battery of claim 1, wherein, The diaphragm is a first diaphragm, which includes a base film (1) and a first base coating (2) that is at least stacked on a first surface of the base film (1) along the thickness direction of the base film (1). The first base coating (2) includes first organic polymer particles (3) that protrude from the surface of the first base coating (2). The thickness of the base film (1) is d, the thickness of the first base coating (2) is d1, and the particle size of the first organic polymer particles (3) is d2. When the base film (1) has only one first base coating layer (2) on its surface, the d gap =d2-d1; When the other surface opposite the first surface of the base film (1) also has a first base coating (2), the d gap = 2 x (d2 - d1); The d1 and the d2 satisfy: 1 <d2 / d1≤3。 3. The lithium-ion battery of claim 1, wherein, The diaphragm is a second diaphragm, which includes a base film (1) and a second base coating (4) that is at least stacked on a first surface of the base film (1) along the thickness direction of the base film (1). A second organic coating (5) is stacked on the surface of the second base coating (4) away from the base film (1). The thickness of the base film (1) is d, the thickness of the second base coating (4) is d1, and the thickness of the second organic coating (5) is d3; when the base film (1) surface has only one of the second base coating layers (4), the d gap = d3; When the other surface opposite the first surface of the base film (1) also has a second base coating (4), the d gap = 2 x d3; The d1 and the d3 satisfy: 0 <d3 / d1≤2。 4. The lithium-ion battery of any one of claims 1 to 3, wherein, The γ value is 90%–98%.

5. The lithium-ion battery of any one of claims 1 to 4, wherein, The d gap is 0.5-4.0 μm.

6. The lithium-ion battery of claim 2 or 3, wherein, The d is 5 to 15 μm, and / or the base membrane (1) is a polyolefin membrane, the base membrane (1) is a polyethylene membrane and / or a polypropylene membrane.

7. The lithium-ion battery of any one of claims 2 to 6, wherein, The d1 is 1 to 5 μm.

8. The lithium-ion battery of any one of claims 2 to 7, wherein, The first base coat (2) and the second base coat (4) are each independently an inorganic particle-binder layer, wherein the inorganic particle-binder layer is selected from any one or more of the following: silica-polyacrylate layer, titanium dioxide-polyacrylate layer, and zinc oxide-polyacrylate layer.

9. The lithium-ion battery of any one of claims 2 to 8, wherein, The d3 is 0.5 to 4.0 μm, and / or the coverage of the second organic coating (5) on the second base coating (4) is 10 to 90%; and / or the second organic coating (5) is a second organic polymer particle-binder layer, and / or the second organic polymer particle-binder layer is a polyvinylidene fluoride particle-polyacrylate layer and / or a polytetrafluoroethylene particle-polyacrylate layer.

10. The lithium-ion battery of any one of claims 2 to 9, wherein, The first organic polymer particle (3) is a styrene-acrylate polymer particle.

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