Preparation method of thin film type integrated busbar and thin film type integrated busbar

Abstract

The invention provides a preparation method of a thin film type integrated busbar, which sequentially comprises the following steps: a film pasting step: pasting a UV thin film containing a UV curing adhesive layer on one or more battery module assemblies to form a thin film assembly to be processed; a cold pressing step: performing cold pressing treatment on the to-be-treated thin film assembly in a normal temperature environment so as to enable the UV thin film to be tightly attached to the battery module assembly; and a UV light curing step: carrying out UV light irradiation treatment on the thin film assembly subjected to cold pressing treatment so as to cure the UV curing adhesive layer, so that the UV thin film and the battery module assembly are bonded into a whole. Through a combined process of'cold pressing first and then UV curing ', the UV film and the surface of the component are ensured to be fully infiltrated and in close contact through cold pressing, and then a glue layer is initiated to be subjected to polymerization reaction through UV light curing to form firm chemical bonding, so that the bonding strength far higher than that of an existing visbreaking process is realized, the problems of layering, falling off and the like of a product are effectively avoided, and the product quality is improved. And the long-term reliability of the product is improved.

Description

Technical Field

[0001] This invention belongs to the field of battery module manufacturing technology, specifically relating to a method for preparing a thin-film integrated busbar and a thin-film integrated busbar. Background Technology

[0002] The CCS (Integrated Busbar) is mainly composed of FPC (Flexible Printed Circuit) and aluminum busbars. It is a multi-functional integrated component that integrates electrical connection, signal acquisition, structural fixation, and insulation protection, featuring high energy density, high safety, and high reliability. As one of the core components of power batteries for new energy vehicles, the integrated busbar integrates multiple functions such as electrical connection, signal acquisition, structural fixation, and insulation protection. Currently, the mainstream integrated busbar processing technologies mainly include hot pressing of polyester film and thermoforming and hot riveting. The hot pressing process uses high temperature and high pressure to press the upper and lower film layers with the internal battery module components; the thermoforming and hot riveting process uses rivets on a thermoforming plate to pass through the components and perform hot-melt riveting. However, these two traditional processes generally suffer from problems such as large equipment investment, high mold costs, long production cycles, and high energy consumption, making it difficult to meet the growing demand for cost reduction and efficiency improvement.

[0003] To simplify the process, one technical solution proposes using a special ultraviolet (UV) photosensitive film to integrate the modules. The principle is as follows: the battery module is attached to a UV-sensitive adhesive film, and then UV light irradiation causes the areas of the film not covered by the module to lose their adhesiveness, thus completing the encapsulation of the module. However, this process, which relies on the "anti-adhesion" principle, focuses on eliminating excess adhesive areas. This often results in insufficient adhesion between the film and the module body, leading to the risk of delamination or detachment during long-term use, thus affecting the final reliability of the product. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing a thin-film integrated busbar, comprising the following steps:

[0005] Film application step: Apply a UV film containing a UV-curable adhesive layer to one or more battery module components to form a film component to be processed;

[0006] Cold pressing step: The film assembly to be processed is subjected to cold pressing at room temperature so that the UV film is tightly bonded to the battery module assembly;

[0007] UV curing step: The film assembly that has undergone cold pressing is subjected to UV light irradiation to cure the UV curing adhesive layer, thereby bonding the UV film to the battery module assembly as one unit.

[0008] Preferably, the cold pressing step is performed at a pressure of 0.2 MPa to 0.3 MPa, and the pressure holding time is 25 to 35 seconds.

[0009] Preferably, the cold pressing step is performed at a pressure of 0.2 MPa.

[0010] Preferably, the UV curing step uses a light source with a wavelength of 365nm for irradiation, and the irradiation time is 7-9 seconds.

[0011] Preferably, the irradiation time is 8 seconds.

[0012] Preferably, at least one of the UV film and the mold for carrying the battery module assembly is provided with positioning holes for alignment.

[0013] Preferably, the UV curing step is achieved by an online UV curing oven set on a conveyor chain.

[0014] Preferably, after the thin film assembly is treated with UV light, the adhesion between the UV film and the battery module assembly increases.

[0015] The present invention also provides a thin-film integrated busbar prepared by the above preparation method, comprising:

[0016] One or more battery module components; and

[0017] A UV film is bonded to one or more battery module components via a UV-cured adhesive layer thereon.

[0018] Preferably, the adhesive force between the UV film and the battery module assembly is greater than or equal to 0.7 kgf / cm.

[0019] Compared with existing technologies, this invention has the following advantages: Through a combined process of "cold pressing followed by UV curing," cold pressing first ensures full wetting and close contact between the UV film and the component surface. Then, UV curing initiates a polymerization reaction in the adhesive layer, forming a strong chemical bond. This achieves a bond strength far exceeding that of existing anti-adhesion processes, effectively avoiding problems such as product delamination and detachment, and improving the long-term reliability of the product. Furthermore, this invention uses room-temperature rapid cold pressing and online UV curing, replacing the traditional time-consuming and energy-intensive hot pressing process, significantly shortening the production cycle, reducing energy consumption and equipment costs, and improving production efficiency. Moreover, since the entire process is carried out at room temperature, damage to the product caused by high temperatures is completely avoided. Therefore, this method is compatible with precision components integrating thermistor electronic components such as battery management systems, and has broad application prospects. Attached Figure Description

[0020] The above and other objects, features, and advantages of the invention will become clearer through a more detailed description of the preferred embodiments illustrated in the accompanying drawings. The same reference numerals denote the same parts throughout the drawings, and the drawings are not intentionally drawn to scale with actual dimensions; the focus is on illustrating the gist of the invention.

[0021] Figure 1 A process flow diagram of a method for preparing a thin-film integrated busbar provided in this application embodiment;

[0022] Figure 2 This is an exploded view of an integrated busbar provided in an embodiment of this application;

[0023] Figure 3 This is a schematic diagram of an automated production line provided in an embodiment of this application. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0025] Example 1

[0026] This embodiment provides a basic fabrication method for thin-film integrated busbars, demonstrating how combining "cold pressing and UV curing" processes can achieve high-strength, high-reliability encapsulation of battery module components. In one embodiment of this application, the process flow corresponds to... Figure 1 The overall process shown includes a film application step S10, a cold pressing step S20, and a UV curing step S30.

[0027] Material preparation is required before the process begins. (Refer to...) Figure 2The integrated busbar prepared in this embodiment mainly consists of a UV film 1 and a battery module assembly 2. The battery module assembly 2 serves as the main body of the integrated busbar, integrating aluminum or copper busbars for electrical connections, a flexible printed circuit board for signal acquisition, and other structural support components. Specifically, in this embodiment, the overall dimensions of the battery module assembly 2 are 300mm x 200mm, with a maximum thickness of 5mm. The selected UV film 1 is a composite film, its structure consisting of a transparent polyethylene terephthalate carrier film, a UV-curable adhesive layer, and a blue release film for protecting the adhesive layer. The UV-curable adhesive layer is an acrylate photosensitive polymer, possessing a certain initial tack to facilitate adhesion when not exposed to UV light; however, upon receiving UV light energy of a specific wavelength, the photoinitiator within it decomposes to generate active free radicals or cations, thereby triggering the polymerization and cross-linking reactions of monomers and prepolymers, ultimately forming a three-dimensional network structure cured material with high cohesive strength and high adhesive strength.

[0028] In step S10, the operator places the pre-prepared battery module assembly 2 onto a dedicated tooling mold. To ensure the accuracy of subsequent film application, the tooling mold is equipped with several positioning pins (e.g., four), whose positions precisely match the pre-drilled holes on the battery module assembly 2, thereby firmly and accurately fixing the battery module assembly 2 in the predetermined position on the mold. Next, a UV film 1, pre-cut according to the outline of the battery module assembly 2, is carefully peeled off from one corner and completely removed to expose the UV-cured adhesive layer with initial tack. Alternatively, the edges of the UV film 1 are also machined with positioning holes that match the positioning pins on the tooling mold. The operator aligns the positioning holes on the UV film 1 with the positioning pins on the mold and smoothly covers the battery module assembly 2 with the UV film 1. Due to the initial tack of the UV-cured adhesive layer, the UV film 1 initially adheres to the surface of the battery module assembly 2. By gently pressing the film from the center outwards using a soft scraper or roller, the UV film 1 can be ensured to be flatly adhered to the surface of the component, and any air that may exist between the film and the component can be eliminated as much as possible, thus forming a film component to be processed.

[0029] Next, the cold pressing step S20 is performed. The tooling mold carrying the aforementioned thin film assembly to be processed is fed into the worktable of a room-temperature cold press. This cold press does not require heating, and the entire pressing process is carried out at room temperature (e.g., 15°C to 30°C). The process parameters of the cold press are set as follows: pressing pressure 0.2 MPa, holding time 30 seconds. After starting the cold press, the upper pressure plate descends, applying uniform pressure to the thin film assembly. Under this pressure, the UV-curable adhesive layer with a certain degree of fluidity further wets the surface microstructure of the battery module assembly 2, filling the tiny unevenness and gaps on its surface, thereby achieving a tighter and gapless physical bond between the UV film 1 and the battery module assembly 2. This step helps to eliminate residual micro-air bubbles and ensure the integrity of the final bonding interface. Correspondingly, this pressure also enables the adhesive layer molecules to be initially activated, creating ideal initial conditions for the subsequent UV curing reaction. After the 30-second holding time, the press automatically releases pressure, and the upper pressure plate rises back.

[0030] Finally, UV curing step S30 is performed. The cold-pressed thin-film assembly is removed from the cold press and fed into an inline UV curing oven via a conveyor chain. This UV curing oven has a tunnel-type structure, with a high-intensity UV light-emitting diode (LED) light source array mounted at the top. The process parameters of the UV curing oven are set so that the center wavelength of the light source is 365nm, which efficiently matches the absorption peak of the photoinitiator in the UV-curable adhesive layer. By adjusting the light source power, the light intensity irradiated onto the component surface reaches 810mW / cm². And by precisely controlling the speed of the conveyor chain, the effective illumination time of the thin-film assembly in the irradiated area is ensured to be 8 seconds. As the thin-film assembly passes through the irradiated area, high-energy UV light penetrates the transparent carrier film and directly acts on the UV-curable adhesive layer. The adhesive layer absorbs sufficient photon energy in a short time, rapidly undergoing polymerization and cross-linking reactions, transforming from a fluid gel into a tough solid. This chemical process is irreversible, forming a strong and permanent chemical bond between the UV thin film 1 and the battery module assembly 2. Understandably, not only the adhesive layer in contact with the battery module component 2 is cured, but the adhesive layer on the UV film 1 in the area not covered by the component is also cured. After curing, the adhesive layer surface in these areas will lose its stickiness and become dry, making it easy for subsequent operation and use, and it will not stick to dust or debris.

[0031] After the above steps, a finished thin-film integrated busbar is prepared. To verify its performance, an adhesive force test was conducted on the finished product. The test method was as follows: a typical bonding area between the UV film 1 and the battery module assembly 2 was selected on the finished product, a sample with a width of 10 mm was cut, and a tensile testing machine was used to perform a 90-degree peel test at a specific speed, and the peel force was recorded. After multiple measurements and averaging, the adhesive force between the UV film 1 and the battery module assembly 2 in the integrated busbar prepared in this embodiment was found to be as high as 1.45 kgf / cm. This value far exceeds the design requirement of 0.7 kgf / cm, indicating that the method provided in this application can achieve an extremely strong bonding effect, which can effectively avoid the risk of delamination, detachment and other failures that may occur under harsh working conditions such as vibration and high and low temperature cycling, and the product has high reliability. At the same time, the entire production process has a fast cycle time and low energy consumption, which verifies the beneficial effects of this application.

[0032] Example 2

[0033] The overall process flow of this embodiment is the same as that of Embodiment 1, which also includes the film application step S10, the cold pressing step S20 and the UV curing step S30. The main difference is in the specific parameter settings of the cold pressing step S20 and the UV curing step S30.

[0034] The material preparation and film application steps S10 are exactly the same as in Example 1. Prepare the same battery module assembly 2 and UV film 1, and use a tooling mold with positioning pins to accurately apply the UV film 1 onto the battery module assembly 2 through the positioning holes to form the film assembly to be processed.

[0035] In the cold pressing step S20, this embodiment uses a relatively high pressure. The component with the film attached is fed into a room temperature cold press, and the pressing pressure is set to 0.3 MPa, which is the upper limit of a preferred pressure range. The higher pressure helps to handle battery module components 2 with more complex surface contours or slightly poor flatness, ensuring that the UV film 1 can achieve a tight, seamless adhesion to the component surface under various conditions. The holding time is still set to 30 seconds, which is within the preferred time range of 25 to 35 seconds, sufficient to ensure sufficient wetting of the adhesive layer.

[0036] In the UV curing step S30, this embodiment uses a different type of light source and a shorter irradiation time. The cold-pressed film assembly is fed into the UV curing oven. It should be noted that in this embodiment, a high-pressure mercury lamp is installed in the curing oven as the light source. The high-pressure mercury lamp is a traditional and mature ultraviolet light source. Although its emission spectrum is multi-lined, its main peak wavelength also covers 365nm, belonging to the UVA band. Therefore, it can also effectively activate the UV-curable adhesive layer used in this embodiment. By adjusting the power of the high-pressure mercury lamp and the speed of the conveyor chain, the effective light intensity on the surface of the assembly is made comparable to that in Example 1, but the effective irradiation time is adjusted to 7 seconds. This time is the lower limit of a preferred irradiation time range of 7 to 9 seconds, designed to verify the adequacy of curing under a shorter irradiation time.

[0037] After completing all the steps, the adhesive strength of the finished integrated busbar was tested. The test results showed that the adhesive strength of the finished product was 1.38 kgf / cm, which was slightly lower than the result of Example 1, but still much higher than the design standard of 0.7 kgf / cm, fully meeting the requirements for high-strength bonding.

[0038] The results of this embodiment demonstrate that the preparation method provided in this application has a wide process window. Excellent-performing finished products can be obtained when the pressure of the cold pressing step is in the range of 0.2 MPa to 0.3 MPa, and the irradiation time of the UV curing step is in the range of 7 to 9 seconds. This proves the stability and industrial applicability of the technical solution of this application, and its ability to adapt to fluctuations in process parameters caused by different equipment and different products.

[0039] Example 3

[0040] In this embodiment, the preferred solution of "online UV curing" is specifically demonstrated.

[0041] Reference Figure 3 This embodiment constructs an automated production line. The core of this automated production line is a conveyor chain 110. Along the travel direction of the conveyor chain 110, a film application station 120, a cold press 130, and an online UV curing oven 140 are arranged in sequence.

[0042] In the film application station 120, UV film 1 is applied to the battery module assembly 2. After application, the film assembly continues to move forward with the conveyor chain 110 and automatically enters the cold press 130. The inlet and outlet of the cold press 130 are designed to allow the conveyor chain 110 to pass directly through. When the sensor detects that the mold has fully entered the pressing area, the conveyor chain 110 pauses, and the cold press 130 automatically performs pressing and holding pressure actions. In this embodiment, the cold pressing parameters are set to 0.25 MPa (within the preferred range of 0.2 MPa to 0.3 MPa) and 30 seconds. After pressing is completed, the press is lifted, and the conveyor chain 110 restarts.

[0043] Next, the cold-pressed film assembly enters an inline UV curing oven 140. This curing oven 140 also allows the conveyor chain 110 to pass through it. Finally, the fully cured finished integrated busbar exits the UV curing oven 140 along with the conveyor chain 110.

[0044] The automated production line layout in this embodiment significantly reduces the labor and time costs per unit product compared to the traditional hot pressing process, fully demonstrating its beneficial effect of "high efficiency".

[0045] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a thin-film integrated busbar, characterized in that, The steps are as follows: Film application step: Apply a UV film containing a UV-curable adhesive layer to one or more battery module components to form a film component to be processed; Cold pressing step: The film assembly to be processed is subjected to cold pressing at room temperature so that the UV film is tightly bonded to the battery module assembly; UV curing step: The film assembly that has undergone cold pressing is subjected to UV light irradiation to cure the UV curing adhesive layer, thereby bonding the UV film to the battery module assembly as one unit.

2. The method for preparing a thin-film integrated busbar according to claim 1, characterized in that, The cold pressing step is carried out under a pressure of 0.2 MPa to 0.3 MPa, and the pressure holding time is 25 to 35 seconds.

3. The method for preparing a thin-film integrated busbar according to claim 1, characterized in that, The cold pressing step is carried out at a pressure of 0.2 MPa.

4. The method for preparing a thin-film integrated busbar according to claim 1, characterized in that, The UV curing step uses a light source with a wavelength of 365nm for irradiation, and the irradiation time is 7-9 seconds.

5. The method for preparing a thin-film integrated busbar according to claim 1, characterized in that, The irradiation time is 8 seconds.

6. The method for preparing a thin-film integrated busbar according to claim 1, characterized in that, At least one of the UV film and the mold for carrying the battery module assembly is provided with positioning holes for alignment.

7. The method for preparing a thin-film integrated busbar according to claim 1, characterized in that, The UV curing step is achieved through an online UV curing oven set on a conveyor chain.

8. The method for preparing a thin-film integrated busbar according to claim 1, characterized in that, After the thin film assembly is treated with UV light, the adhesion between the UV film and the battery module assembly increases.

9. The thin-film integrated busbar prepared by the preparation method according to any one of claims 1-8, characterized in that, include: One or more battery module components; as well as A UV film is bonded to one or more battery module components via a UV-cured adhesive layer thereon.

10. The thin-film integrated busbar according to claim 9, characterized in that, The adhesion force between the UV film and the battery module assembly is greater than or equal to 0.7 kgf / cm.

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