Application of 0.01mm PI Composite Copper Foil in Photovoltaic Modules for New Energy Vehicles

Flexible circuit board is a highly reliable and excellent flexible printed circuit board made of polyimide or polyester film as the substrate. Soft board, also known as FPC, has the characteristics of high wiring density, light weight, and thin thickness. In order to provide sufficient support strength for soldering or inserting connectors on flexible circuit boards, it is often necessary to bond reinforcement at local locations as support bodies to improve the strength of the insertion area and facilitate the overall composition of the product.

At present, reinforcement plates mainly include stainless steel reinforcement plates, aluminum foil reinforcement plates, polyester reinforcement plates, polyimide reinforcement plates, glass fiber reinforcement plates, polytetrafluoroethylene reinforcement plates, and polycarbonate reinforcement plates, which are used inflexible circuit boardThe main reinforcement materials used are polyester reinforcement plate and polyimide reinforcement plate (PI reinforcement plate). PI reinforcement plate can generally be divided into single-layer thick plate and composite PI reinforcement plate. Composite reinforcement plate,

The polyimide reinforcement board consists of an ink layer, a polyimide composite film layer, and an adhesive layer that adheres the polyimide composite film to the printed circuit board, resulting in improved heat dissipation performance. The high reflectivity white PI composite film prepared by Advanced Institute Technology includes a white ink layer, PI film layer, adhesive layer, and release paper. The prepared composite reinforcement board has high gloss and high brightness effects. However, the current research focus of PI composite reinforcement film is mostly on heat resistance and aging resistance, and there is insufficient research on impact resistance and magnetic interference resistance.

The thickness of the PI film layer is 23-27 μ m, the thickness of the halogen-free white ink layer is 16-20 μ m, and the thickness of the halogen-free epoxy adhesive layer is 23-27 μ m,Copper foilThe thickness is 7-8 μ m. Preferably, the surface of the copper foil in contact with the halogen-free epoxy adhesive layer is provided with irregular texture patterns.

Compared with existing technology, the beneficial effects of this product are:

1. Halogen free white ink layer, 2. PI film layer, 3. Halogen free epoxy adhesive layer, 4. Copper foil layer.

Copper foil PI composite white reinforcement board, from top to bottom, includes a halogen-free white ink layer 1 with a thickness of 18 μ m, a PI film layer 2 with a thickness of 25 μ m, a halogen-free epoxy adhesive layer 3 with a thickness of 25 μ m, and a copper foil layer 4 with a thickness of 7 μ m; First, coat the pre configured halogen-free white ink prepared from epoxy resin modified acrylic resin on the upper surface of PI film layer 2, dry it at a temperature of 160 ℃, coat the pre configured halogen-free epoxy adhesive layer 3 on the lower surface of PI film layer 2, dry it at a temperature of 160 ℃, and then roll press it on a three roll rolling machine at a pressure of 5kgf/cm. Then, press the composite film with irregular texture copper foil surface 4 at a temperature of 160 ℃ and a pressure of 10kgf/cm for 15 minutes, followed by constant temperature of 160 ℃, a pressure of 25kgf/cm, a pressure of 45min, and finally cool it down to room temperature with a pressure of 5kgf/cm./cm, pressing time of 30 minutes, winding, to obtain the finished product.

The COF scheme mainly uses a mixture of polyimide (PI film) materials, with a thickness of only 50-100um and a line width and spacing of less than 20um. COF packaging is produced using automated roll to roll equipment, which is continuously heated to 400 degrees Celsius during the production process. Due to the need for heating during the COF roll to roll production process, and the thermal expansion coefficient of PI film being 16um/m/C, compared to the chip's 2.49um/m/C, the thermal stability is poor, thus requiring high equipment accuracy and process requirements.

The use of FPC is generally made by bonding copper foil and PI film material to form a flexible copper foil substrate (FCCL), and materials such as cover layer, reinforcement plate, and anti-static layer are used to make the flexible board. The thickness of PI film can be mainly divided into 0.5mil, 1mil, 2mil, 3mil, and thick film (even products above 10mil). Advanced or advanced soft boards require thinner (0.3mil) and more stable PI film in terms of size stability. The general covering film mainly uses PI film with a thickness of 0.5mil, while thicker PI film is mainly used for reinforcing plates and other purposes.