Composite current collector

Abstract

The utility model provides a composite current collector. The composite current collector comprises a structure and a base film layer, the two metal film layers are located on the two faces of the base film layer respectively, and hole structures are evenly distributed on the metal film layers; and the PPTC film layers are respectively positioned on the metal film layers. The composite current collector provided by the utility model has the characteristics of light weight and high reliability, is compact in device structure, and realizes over-current and over-temperature negative feedback protection in the battery.

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, bringing significant challenges to safety performance. Composite current collectors with metal / polymer / metal layer structures have attracted widespread attention due to their lightweight and high safety characteristics. The bonding force between the metal film and polymer film layers in composite current collectors has always been a difficult problem to improve in composite current collector production technology and is also a common failure mode. On the other hand, battery safety failures are usually related to overcurrent and overtemperature. Components made of polymer PTC material (PPTC) connected in series in electronic circuits can maintain continuity under normal operating temperature and rated current conditions, but the resistance increases sharply under overtemperature or high current conditions, causing the circuit to shut down. After the fault is cleared, the circuit can automatically recover to a low-resistance state, playing a self-recovery protection role in the circuit. Existing technology connects a secondary PPTC protection between the negative electrode of the cell and the protection board, which plays a role in increasing resistance and maintaining temperature under overcurrent and external overtemperature conditions. However, its ability to indicate overtemperature inside the battery is limited, and it cannot directly cut off over-discharge inside the battery, providing protection without immediate detection. Therefore, the reliability, lightweighting, and safety of power battery current collectors are urgent problems to be solved. Utility Model Content

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

[0004] To achieve the above and other related objectives, this utility model provides a composite current collector, comprising the following structure:

[0005] Base film layer;

[0006] Two metal film layers are located on both sides of the base film layer, and the metal film layers have uniformly distributed porous structures.

[0007] PPTC films are located on the metal films.

[0008] Optionally, the base film layer includes one of polyimide (PI) film, polyetherimide (PEI) film, and polyethylene naphthalate (PEN) film, with a thickness of 10-20 μm.

[0009] Optionally, the metal film layer is either a copper film or an aluminum film, with a thickness of 0.5 μm to 5 μm.

[0010] Optionally, the polymer PTC film (PPTC film) layer has a thickness of 1μm to 5μm, is composed of a polymer substrate and conductive filler, has a room temperature conductivity greater than 1S / cm, and a PTC transition temperature of 60 to 100℃.

[0011] Optionally, the area of ​​the uniformly distributed hole structure accounts for 1 / 4 to 1 / 3 of the total area.

[0012] As described above, the composite current collector of this invention has the following beneficial effects: a chemically inert PPTC protective film is coated onto the metal film layer of a traditional composite current collector. Simultaneously, porous areas are uniformly distributed on the metal film, and the PPTC film adheres to the base film, acting as a anchoring effect on the overall structure and improving the adhesion strength between the metal film, the base film, and the PPTC film. This composite current collector is lightweight and highly reliable, with a compact device structure, achieving negative feedback protection against overcurrent and overtemperature within the battery. Attached Figure Description

[0013] Figure 1 The diagram shown is a flow chart of a composite current collector structure according to this utility model.

[0014] Figure 2 The diagram shows the structural schematics of each step in the manufacturing method of the composite current collector according to this utility model.

[0015] Component designation explanation:

[0016] 1. Base membrane

[0017] 2 metal film

[0018] 3 PPTC film layer

[0019] 5. Pores on the metal film Detailed Implementation

[0020] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can understand the invention from the details disclosed in this specification.

[0021] The contents of this specification make it easy to understand other advantages and effects of this utility model. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0022] See Figure 1 and 2 It should be noted that the illustrations provided in this embodiment are merely schematic representations of the basic principles of this utility model.

[0023] The illustrations only show components relevant to this invention and are not drawn according to the actual number, shape, and size of the components in the actual implementation. In the 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.

[0024] A composite current collector structure is as follows Figure 1 As shown: A base film layer 1 is provided, with metal layers 2 on both sides of the base film. Hole structures 5 are uniformly distributed on the metal film layers. The base film layer 1 can be one of a PI film, a PEI film, or a PEN film, with a thickness of 10–20 μm. The metal film layer 2 can be one of a copper film or an aluminum film, with a thickness of 0.5 μm–5 μm. The area of ​​the uniformly etched holes 5 on it accounts for 1 / 4–1 / 3 of the total area. A PPTC film layer 3 is located on the metal film layer 2, with a room temperature conductivity greater than 1 S / cm and a PTC transition temperature of 60–100℃.

[0025] In summary, this invention provides a composite current collector that coats a chemically inert PPTC protective film layer onto a conventional composite current collector's metal film layer. Simultaneously, porous areas are uniformly distributed on the metal film, and the PPTC film layer adheres to the base film, acting as a anchoring element for the overall structure and enhancing the adhesion strength between the metal film, the base film, and the PPTC film layer. This composite current collector is lightweight and highly reliable, with a compact device 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 significant industrial value.

[0026] 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 current collector, characterized in that: Includes structure: Base film layer; Two metal film layers are located on both sides of the base film layer, and the metal film layers have a uniformly distributed porous structure. Polymer PTC film layers are located on the outer side of the metal film layer.

2. The composite current collector according to claim 1, characterized in that: The base film layer includes one of PI polyimide film, PEI polyetherimide film, and polyethylene naphthalate film, with a thickness of 10-20 μm.

3. The composite current collector according to claim 1, characterized in that: The metal film layer is either a copper film or an aluminum film, and its thickness is 0.5μm to 5μm.

4. The composite current collector according to claim 1, characterized in that: The polymer PTC 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℃.

5. The composite current collector according to claim 1, characterized in that: The area of ​​the uniformly distributed hole structure accounts for 1 / 4 to 1 / 3 of the total area.

Images