Composite safety current collector

Abstract

The utility model provides a kind of composite safety current collector, structure includes release layer;First PPTC film layer is located one side of the release layer;Second PPTC film layer is located the other side of the release layer;On the first PPTC film layer, it is first copper metal layer, first adhesive layer, second copper metal layer outward in turn;On the second PPTC film layer, it is first aluminum metal layer, second adhesive layer, second aluminum metal layer outward in turn.The utility model composite current collector has lightweight and high safety characteristics, device structure is compact, realizes the negative feedback protection of battery internal overcurrent overtemperature.

Description

Technical Field

[0001] This utility model relates to the field of functional materials technology, and in particular to current collector components for battery cells. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the capacity and cycle performance of power batteries are constantly improving, leading to increasingly higher requirements for lightweighting and safety. Composite current collectors with a metal layer / polymer layer / metal layer structure possess excellent characteristics of lightweighting and high safety. They can effectively prevent puncture-induced fires while significantly reducing metal thickness. However, traditional intermediate polymer layers are prone to defects such as wrinkles after coating and during winding. Furthermore, battery safety failures are often related to overcurrent and overtemperature. Components made of PPTC material, connected in series in electronic circuits, can maintain continuity under normal operating temperature and rated current conditions. Under overtemperature or high current conditions, the resistance increases sharply, causing the circuit to shut down. After fault resolution, the circuit can automatically recover to a low-resistance state, providing self-recovery protection. However, PPTC is typically applied using a separate, lengthy coating process when used in current collectors or composite current collectors. Therefore, structural and process optimization for lightweighting and safety of power battery current collectors is essential. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a composite safety current collector and its manufacturing method, so as to solve the problems of lightweighting and safety of power batteries in the prior art.

[0004] To achieve the above and other related objectives, this utility model provides a composite safety current collector, comprising the following structure: Release layer; The first PPTC film layer is located on one side of the release layer; The second PPTC film layer is located on the other side of the release layer; On the first PPTC film layer, outwardly there are a first copper metal layer, a first adhesive layer, and a second copper metal layer; On the second PPTC film layer, from the outside outwards are the first aluminum metal layer, the second adhesive layer, and the second aluminum metal layer.

[0005] Optionally, the release layer includes a PI film or a PET film, with a release force of 3~12gf / 25mm.

[0006] Optionally, the adhesive layer is one of epoxy adhesive layer, acrylic adhesive layer, and polyurethane adhesive layer, with a thickness of 10~20μm.

[0007] Optionally, the thickness of the copper metal layer is 0.1 μm to 5 μm; the thickness of the aluminum metal layer is 0.5 μm to 10 μm.

[0008] Optionally, the PPTC film layer has a thickness of 1μm to 5μm and is composed of a polymer substrate and a conductive filler; the polymer substrate includes one or a mixture of PVDF, P(VDF-HFP), and P(VDF-HFP-TrFE); the conductive filler is one of carbon black, graphene, metal carbide particles, and metal boride particles; the room temperature conductivity is greater than 1S / cm, and the PTC transition temperature is 60~100℃.

[0009] The composite safety current collector of this utility model is applied to lithium-ion power batteries. The release layer is rolled out and peeled off from both sides and applied to the positive and negative electrodes of the lithium-ion battery.

[0010] As described above, the composite safety current collector and its manufacturing method of this utility model have the following beneficial effects: This utility model forms a "PPTC / metal / adhesive layer / metal" structure on both sides of the release film, which is applied to the positive and negative electrodes of a columnar power battery, respectively. After winding, the chemically inert PPTC layer faces outwards, providing overcurrent and overtemperature protection. This composite current collector features lightweight design and high safety, with a compact device structure, achieving negative feedback protection against internal overcurrent and overtemperature in the battery. Attached Figure Description

[0011] Figure 1 The diagram shown is a structural schematic of a composite safety current collector according to this utility model.

[0012] Figure 2 The diagram shown is a schematic of a composite safety current collector used in the winding of a lithium-ion power battery according to this utility model.

[0013] Component designation explanation: 1. Release layer 21 First PPTC film layer 22 Second PPTC film layer 31 First copper metal layer 32 Second copper metal layer 41 First adhesive layer 42 Second adhesive layer 51 First aluminum metal layer 52 First aluminum metal layer Detailed Implementation

[0014] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0015] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. The illustrations only show the components related to this utility model and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0016] This embodiment provides a composite safety current collector, such as Figure 1 As shown, the composite safety current collector structure includes; Release layer 1; Release layer 1 can be PI film or PET film, with a release force of 3~12gf / 25mm.

[0017] The first PPTC film layer 21 is located on one side of the release layer 1; the second PPTC film layer 22 is located on the other side of the release layer 1; the PPTC film layer has a thickness of 1μm~5μm and is composed of a polymer substrate and a conductive filler; the polymer substrate includes one of PVDF, P(VDF-HFP), and P(VDF-HFP-TrFE) or a mixture thereof; the conductive filler is one of carbon black, graphene, metal carbide particles, and metal boride particles; the room temperature conductivity is greater than 1S / cm, and the PTC transition temperature is 60~100℃.

[0018] On the first PPTC film layer 21, outwardly arranged are a first copper metal layer 31, a first adhesive layer 41, and a second copper metal layer 32; on the second PPTC film layer 22, outwardly arranged are a first aluminum metal layer 51, a second adhesive layer 42, and a second aluminum metal layer 52. The copper metal layer has a thickness of 0.1μm to 5μm; the adhesive layer is one of epoxy adhesive, acrylic adhesive, or polyurethane adhesive, with a thickness of 10 to 20μm; the aluminum metal layer has a thickness of 0.5μm to 10μm.

[0019] like Figure 2 As shown, the composite safety current collector is used in lithium-ion power batteries. The release layer 1 is rolled out and peeled off from both sides. The copper layer side and the aluminum layer side are used as the negative electrode and positive electrode of the lithium-ion battery, respectively.

[0020] In summary, this invention provides a composite safety current collector and its manufacturing method. The invention forms a "PPTC / metal / adhesive layer / metal" structure on both sides of a release film, which is applied to the positive and negative electrodes of a cylindrical power battery, respectively. After winding, the chemically inert PPTC layer faces outwards, providing overcurrent and overtemperature protection. This composite current collector is lightweight and highly safe, with a compact structure, achieving negative feedback protection against internal overcurrent and overtemperature in the battery. Therefore, this invention effectively overcomes the shortcomings of existing technologies and possesses high industrial value.

[0021] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A composite safety current collector, characterized in that: Includes structure: Release layer; The first PPTC film layer is located on one side of the release layer; The second PPTC film layer is located on the other side of the release layer; On the first PPTC film layer, outwardly there are a first copper metal layer, a first adhesive layer, and a second copper metal layer; On the second PPTC film layer, from the outside outwards are the first aluminum metal layer, the second adhesive layer, and the second aluminum metal layer.

2. The composite safety current collector according to claim 1, characterized in that: The release layer includes PI film and PET film, with a release force of 3~12gf / 25mm.

3. The composite safety current collector according to claim 1, characterized in that: The adhesive layer is one of epoxy adhesive layer, acrylic adhesive layer, and polyurethane adhesive layer, with a thickness of 10~20μm.

4. The composite safety current collector according to claim 1, characterized in that: The thickness of the copper metal layer is 0.1μm to 5μm; the thickness of the aluminum metal layer is 0.5μm to 10μm.

5. The composite safety current collector according to claim 1, characterized in that: The PPTC film has a thickness of 1μm to 5μm, a room temperature conductivity greater than 1S / cm, and a PTC transition temperature of 60 to 100℃.

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