Polypropylene-based composite current collector, electrode plate and battery
By setting up a raised structure on the surface of the polypropylene-based film layer and setting up a metal reinforcement layer and a conductive metal layer up and down, the problem of easy falling off of the polypropylene-based composite liquid collector metal layer is solved, and the service life of the current collector is improved.
Patent Information
- Application Number
- CN202421439687.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-21
- Publication Date
- 2025-05-23
- Estimated Expiration
- 2034-06-21
AI Technical Summary
The metal layer on the polypropylene-based composite liquid collector is prone to fall off, resulting in a short life of the current collector.
A plurality of protrusions are distributed on the surface of the polypropylene base film layer, and a metal reinforcement layer is provided on both upper and lower surfaces to form a conductive metal layer and an oxidation-resistant layer to improve the adhesion of the metal layer.
The convex structure improves the viscosity of the polypropylene base film layer to the metal reinforcement layer and the conductive metal layer, prevents the metal layer from falling off, and extends the service life of the current collector.
Smart Images
Figure CN222896696U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of current collectors, and in particular to a polypropylene-based composite current collector, an electrode sheet, and a battery. Background Art
[0002] Lithium-ion batteries have been widely used in consumer electronics, electric vehicles and other fields. With the continuous development of the battery industry, current collectors with better performance are needed. Composite current collectors are a new type of current collector material, usually made of a polymer film substrate layer and a conductive metal layer plated on both sides of the polymer film substrate layer, forming a "sandwich structure". Compared with pure metal current collectors, the weight of composite current collectors can be reduced by 50% to 80%. At the same time, the thickness of the composite current collector is also reduced by 25%-40% compared to the thickness of the pure metal current collector, so that the space in the battery can be transferred to the electrode active material. The presence of the polymer substrate layer in the composite current collector can reduce the temperature rise of the battery and reduce the risk of thermal runaway of the battery.
[0003] However, the surface of the polymer film is very flat and smooth, and the reinforcement layer and the metal layer deposited on it are easy to fall off, especially for non-polar materials such as polypropylene. Adhesion is a big problem. The metal layer on the polypropylene-based composite current collector is easy to fall off, resulting in a short life of the current collector. Utility Model Content
[0004] The utility model discloses a polypropylene-based composite current collector with a simple structure, and aims to improve the problem that a metal layer on the polypropylene-based composite current collector is easy to fall off, resulting in a short service life of the current collector.
[0005] The utility model adopts the following scheme:
[0006] The present application provides a polypropylene-based composite current collector, comprising: a polypropylene-based film layer, wherein a plurality of protrusions are distributed on the surface of the polypropylene-based film layer; a metal reinforcement layer is arranged on both the upper and lower surfaces of the polypropylene-based film layer, a conductive metal layer is arranged on one side of the two metal reinforcement layers away from the polypropylene-based film layer, and an anti-oxidation layer is formed on one side of the two conductive metal layers away from the metal reinforcement layers.
[0007] Furthermore, the protrusions are distributed on the surface of the polypropylene-based film layer at uniform intervals or in repeated regional distributions.
[0008] Furthermore, the protrusion is arc-shaped or circular, with a diameter of ≤300 μm, and a height of the protrusion of ≤2 μm.
[0009] Furthermore, the two conductive metal layers are both made of copper or aluminum, or one of the conductive metal layers is copper and the other conductive metal layer is aluminum.
[0010] Furthermore, when the conductive metal layer is copper, the anti-oxidation layer is covered on a side of the conductive metal layer away from the metal reinforcement layer through a plating process; when the conductive metal layer is aluminum, the anti-oxidation layer is naturally formed aluminum oxide.
[0011] Furthermore, the thickness of the polypropylene-based film layer with protrusions is 1-15 μm; the thickness of each metal reinforcement layer is 0.001-0.08 μm; and the thickness of each conductive metal layer is 0.2-3 μm.
[0012] Furthermore, the polypropylene-based film layer with protrusions has a thickness of 3-10 μm; and the thickness of each conductive metal layer is 0.5-1.5 μm.
[0013] Furthermore, the metal reinforcement layer is one or more alloys of Ni, Ti, Cr, Zr, Nb, Al, and Cu, or an oxide of Ni, Ti, Cr, Zr, Nb, Al, and Cu.
[0014] The utility model also provides an electrode sheet, which is made by any one of the polypropylene-based composite current collectors described above.
[0015] The utility model also provides a battery, at least one of the positive electrode and the negative electrode of the battery adopts the electrode sheet.
[0016] Beneficial effects:
[0017] By arranging a plurality of arc-shaped or circular protrusions that are evenly or repeatedly arranged on the polypropylene base film layer, the adhesion of the surface of the polypropylene base film layer to the metal reinforcement layer and the conductive metal layer is improved, making it difficult for the metal reinforcement layer to fall off the polypropylene base film layer, thereby improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a schematic diagram of the hierarchical structure of a polypropylene-based composite current collector according to an embodiment of the utility model;
[0019] Figure 2 This is a schematic diagram of the protrusion distribution of a polypropylene-based composite current collector according to an embodiment of the utility model, in which the protrusions are distributed in a repeated regional manner;
[0020] Figure 3 This is a schematic diagram of the protrusion distribution of a polypropylene-based composite current collector in an embodiment of the utility model, in which the protrusions are distributed at uniform intervals;
[0021] Icon: polypropylene base film layer 1, metal reinforcement layer 2, conductive metal layer 3, anti-oxidation layer 4, protrusion 5. DETAILED DESCRIPTION
[0022] Example 1
[0023] This embodiment provides a battery, wherein at least one of the positive electrode and the negative electrode is an electrode sheet made of a polypropylene-based composite current collector.
[0024] Combination Figures 1 to 3 As shown, the polypropylene-based composite current collector includes: a polypropylene-based film layer 1, and a plurality of protrusions 5 are distributed on the surface of the polypropylene-based film layer 1; a metal reinforcement layer 2 is provided on the upper and lower surfaces of the polypropylene-based film layer 1, and a conductive metal layer 3 is provided on the side of the two metal reinforcement layers 2 away from the polypropylene-based film layer 1, and an anti-oxidation layer 4 is formed on the side of the two conductive metal layers 3 away from the metal reinforcement layer 2.
[0025] Combination Figure 2 and Figure 3 As shown, the protrusions 5 are evenly spaced or repetitively distributed in the region on the surface of the polypropylene base film layer 1. Here, the protrusions 5 are set to be arc-shaped or circular, and their diameter is ≤300μm. Several protrusions 5 can form a variety of repetitive patterns, and the height of the protrusions 5 is ≤2μm, preferably 0.2-1μm; the thickness of the protrusions 5 in the part with arc-shaped or circular protrusions 5 is 1-15μm, preferably 3-10μm; the bottom width of the protrusions 5 is 0.1-15μm, preferably 3-10μm. The bottom width here refers to the diameter of the circular protrusion. Here, when the protrusions 5 are evenly spaced, a rectangular distribution can be formed; when the protrusions 5 are repetitively distributed in the region, a circle can be formed by several protrusions 5, and the diameter of the circle is ≤300μm. The adhesion of the polypropylene base film layer 1 to the metal reinforcement layer 2 is improved by arranging multiple groups of the circles.
[0026] The metal reinforcement layer 2 is formed on the upper and lower sides of the polypropylene base film layer 1. The metal reinforcement layer 2 is one or more alloys of Ni, Ti, Cr, Zr, Nb, Al, and Cu, or oxides of Ni, Ti, Cr, Zr, Nb, Al, and Cu. It is formed on both sides of the polypropylene base film layer 1 by physical vapor deposition, and the thickness of each layer of the metal reinforcement layer 2 is 0.001-0.08 μm.
[0027] In this embodiment, the two conductive metal layers 3 are either copper or aluminum, or one of the conductive metal layers 3 is copper and the other conductive metal layer 3 is aluminum. When the conductive metal layer 3 is copper, the conductive metal layer 3 is prepared on the outer surface of the metal reinforcement layer 2 by physical vapor deposition or chemical deposition; when the conductive metal layer 3 is aluminum, the conductive metal layer 3 is prepared on the surface of the metal reinforcement layer 2 by physical vapor deposition. The thickness of the conductive metal layer 3 on each side is 0.2-3 μm, preferably 0.5-1.5 μm.
[0028] The anti-oxidation layer 4 is arranged on the outer surface of the conductive metal layer 3 to play a protective role. The anti-oxidation layer 4 is formed in different ways according to the different materials of the conductive metal layer 3. Specifically, when the conductive metal layer 3 is copper, the anti-oxidation layer 4 is prepared on both surfaces of the conductive metal layer 3 by contacting with an antioxidant and drying; when the conductive metal layer 3 is aluminum, the anti-oxidation layer 4 is formed by naturally formed aluminum oxide. The thickness of the anti-oxidation layer 4 here is 0.002-2μm, preferably 0.002-0.1μm.
[0029] Through this embodiment, the protrusion 5 is provided, and when the metal reinforcement layer 2 is formed on the polypropylene base film layer 1 and when the conductive metal layer 3 is formed on the metal reinforcement layer 2, the surface has the protrusion 5 structure, which improves the adhesion of the polypropylene base film layer 1 to the metal reinforcement layer 2 and the adhesion of the metal reinforcement layer 2 to the conductive metal layer 3, effectively prevents the problem of falling off between different layers, and improves product quality.
[0030] Example 2
[0031] This embodiment uses polypropylene with arc-shaped or circular protrusions 5 as the base film layer, the metal reinforcement layer 2 is deposited on the polypropylene base film layer 1 with a thickness of 0.01μm, the thickness of the polypropylene base film layer 1 is 4.5μm, the diameter of the arc-shaped or circular protrusion 5 is 90-110μm, the height of the protrusion 5 is 0.4-0.6μm, the bottom width of the protrusion 5 is 4.5-8.5μm, and the protrusions 5 are evenly spaced; the conductive metal layer 3 is copper with a thickness of 0.8μm, and the anti-oxidation layer is 40.003μm.
[0032] Example 3
[0033] This embodiment uses polypropylene with arc-shaped or circular protrusions 5 as the base film layer, the thickness of the metal reinforcement layer 2 deposited on the polypropylene base film layer 1 is 10nm, the thickness of the polypropylene base film layer 1 is 4.5μm, the diameter of the arc-shaped or circular protrusion 5 is 90-110μm, the height of the protrusion 5 is 0.4-0.6μm, the bottom width of the protrusion 5 is 4.5-8.5μm, the protrusion 5 is distributed in a repeated regional manner, the conductive metal layer 3 is aluminum with a thickness of 0.8μm, and the anti-oxidation layer is 40.003μm.
[0034] Example 4
[0035] Polypropylene with arc-shaped or circular protrusions 5 is used as the polypropylene base film layer 1, the thickness of the metal reinforcement layer 2 deposited on the polypropylene base film layer 1 is 15nm, the thickness of the polypropylene base film layer 1 is 6μm, the diameter of the arc-shaped or circular protrusion 5 is 80-100μm, the height of the protrusion 5 is 0.7-1μm, the bottom width of the protrusion 5 is 10.5-12.5μm, and the protrusions 5 are evenly distributed; the conductive metal layer 3 is aluminum with a thickness of 1μm, and the anti-oxidation layer is 40.002μm.
[0036] Example 5
[0037] Polypropylene with arc-shaped or circular protrusions 5 is used as the polypropylene base film layer 1, the thickness of the metal reinforcement layer 2 deposited on the polypropylene base film layer 1 is 20nm, the thickness of the polypropylene base film layer 1 is 6μm, the diameter of the arc-shaped or circular protrusion 5 is 80-100μm, the height of the protrusion 5 is 0.7-1μm, the bottom width of the protrusion 5 is 10.5-12.5μm, and the protrusions 5 are evenly distributed; the conductive metal layer 3 is copper with a thickness of 1.5μm, and the anti-oxidation layer is 40.003μm.
[0038] Comparative Example 1
[0039] Ordinary smooth-surfaced polypropylene is used as the polypropylene base film layer 1, the metal reinforcement layer 2 is deposited on the polypropylene base film layer 1 with a thickness of 10nm, the thickness of the polypropylene base film layer 1 is 4.5μm, the conductive metal layer 3 is copper with a thickness of 0.8μm, and the anti-oxidation layer is 40.003μm.
[0040] Comparative Example 2
[0041] Ordinary smooth-surfaced polypropylene is used as the polypropylene base film layer 1, the metal reinforcement layer 2 is deposited on the polypropylene base film layer 1 with a thickness of 15nm, the thickness of the polypropylene base film is 6μm, the conductive metal layer 3 is aluminum with a thickness of 1μm, and the anti-oxidation layer is 40.002μm.
[0042] Comparative Example 3
[0043] Ordinary smooth-surfaced polypropylene is used as the polypropylene base film layer 1, the metal reinforcement layer 2 is deposited on the polypropylene base film layer 1 with a thickness of 20nm, the thickness of the polypropylene base film is 6μm, the conductive metal layer 3 is copper with a thickness of 1.5μm, and the anti-oxidation layer is 40.003μm.
[0044] The above embodiments and comparative examples were subjected to a pull-off adhesion test to test the adhesion between the metal layer and the polypropylene base film:
[0045] sample Adhesion / MPa Example 2 3.75 Example 3 3.54 Example 4 3.66 Example 5 3.89 Comparative Example 1 0.89 Comparative Example 2 1.32 Comparative Example 3 1.10
[0046] It can be seen from the above adhesion test that the adhesion between the polypropylene base film layer 1 provided with the protrusions 5 and the metal reinforcement layer 2 is much greater than the adhesion between the ordinary polypropylene base film layer 1 and the metal reinforcement layer 2.
[0047] It should be understood that the above are only preferred implementations of the present utility model, and the protection scope of the present utility model is not limited to the above embodiments. All technical solutions under the concept of the present utility model belong to the protection scope of the present utility model.
[0048] The above description of the drawings used in the implementation manner only shows certain embodiments of the utility model and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.
Claims
1. A polypropylene-based composite current collector, characterized in that: include: A polypropylene base film layer, wherein a plurality of protrusions are distributed on the surface of the polypropylene base film layer; a metal reinforcement layer is arranged on both the upper and lower surfaces of the polypropylene base film layer, a conductive metal layer is arranged on one side of the two metal reinforcement layers away from the polypropylene base film layer, and an anti-oxidation layer is formed on one side of the two conductive metal layers away from the metal reinforcement layers.
2. The polypropylene-based composite current collector according to claim 1, characterized in that: The protrusions are distributed on the surface of the polypropylene base film layer in a uniform spacing or in a repeated regional distribution.
3. The polypropylene-based composite current collector according to claim 2, characterized in that: The height of the protrusion is ≤2 μm.
4. The polypropylene-based composite current collector according to claim 1, characterized in that: The two conductive metal layers are both made of copper or aluminum, or one of the conductive metal layers is copper and the other conductive metal layer is aluminum.
5. The polypropylene-based composite current collector according to claim 4, characterized in that: When the conductive metal layer is copper, the anti-oxidation layer is covered on a side of the conductive metal layer away from the metal reinforcement layer through a plating process; when the conductive metal layer is aluminum, the anti-oxidation layer is naturally formed aluminum oxide.
6. The polypropylene-based composite current collector according to claim 1, characterized in that: The thickness of the polypropylene-based film layer with protrusions is 1-15 μm; the thickness of each metal reinforcement layer is 0.001-0.08 μm; and the thickness of each conductive metal layer is 0.2-3 μm.
7. The polypropylene-based composite current collector according to claim 6, characterized in that: The thickness of the polypropylene-based film layer with protrusions is 3-10 μm; the thickness of each conductive metal layer is 0.5-1.5 μm.
8. The polypropylene-based composite current collector according to claim 1, characterized in that: The metal reinforcement layer is one or more alloys of Ni, Ti, Cr, Zr, Nb, Al, and Cu, or oxides of Ni, Ti, Cr, Zr, Nb, Al, and Cu.
9. An electrode sheet, characterized in that: The polypropylene-based composite current collector is made from any one of claims 1 to 8.
10. A battery, characterized in that: At least one of the positive electrode and the negative electrode adopts the electrode sheet according to claim 9.