Detailed explanation of copper outer cap product industry knowledge

 

The copper outer cap is a key structural component at both ends of the high-voltage fuse of electric vehicles. It is sealed and connected with the fuse ceramic tube body or metal end cap through welding to form a sealed cavity that accommodates the melt and arc-extinguishing medium. This component not only assumes the dual functions of mechanical support and electrical connection, but also helps maintain the integrity of the cavity structure when the fuse breaks fault current and prevents the leakage of high-temperature and high-pressure gas. Among cylindrical fuses, Copper End Caps Round is the most common structural form. Its inner and outer diameter dimensions and wall thickness need to be precisely matched with the ceramic tube body. For fuses that require soldering or silver soldering assembly, Copper End Cap Solder Fittings are copper end caps suitable for soldering assembly. There are solder grooves or soldering positioning features on the end face or inside to facilitate the accurate placement of the solder and the even flow after melting. For the welding fuse structure, the Welding Fuse Copper Pipe End Cap is the welding fuse copper pipe end cap. It is usually connected to the copper pipe or ceramic pipe body through resistance welding or laser welding. The end cap is required to have good welding adaptability and consistent wall thickness distribution.

 

Copper Cap High Pressure OEM is a customized copper outer cap product for high-voltage applications. It is specially used for electric vehicle fuses with higher rated voltage. The wall thickness and material hardness need to be specially designed to withstand higher arc pressure. Copper Outer End Cap for High Voltage Low Current EV Fuse is a copper outer cap for high voltage and low current electric vehicle fuses. It is a subdivided product that has appeared in recent years with the popularization of 800V high-voltage platforms. It is characterized by a relatively small outer diameter but needs to withstand high voltage stress. Copper Cap for BS (British Standard) Type Fuse is a copper cap for British Standard fuses, which must comply with the size and material requirements of the outer cap in the BS 88 or BS 1362 standards. Copper Cap for Cylindrical Fuses is a copper cap for cylindrical fuses, covering a variety of standard specifications from 5mm×20mm to 10mm×38mm. Copper Outer Cap for Eaton Bussmann Fuse is a copper outer cap adapted to Eaton Bussmann series fuses, which represents the industry's higher requirements for dimensional interchangeability and welding reliability. Copper Outer Cap for Industrial Power Fuse is a copper outer cap for industrial power fuses. It is usually larger in size and thicker in wall thickness to withstand higher short-circuit currents and more frequent operating impacts in industrial environments.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The material of the copper outer cap is copper (pure copper, generally T2 or C11000), and its copper content is not less than 99.9%. Copper has high electrical conductivity (up to 100% IACS or above), good thermal conductivity and excellent ductility. These characteristics make it an ideal material for fuse end caps. The high conductivity ensures that the end cap itself will not produce significant temperature rise when the fuse is operating normally; good thermal conductivity helps to quickly conduct the heat generated when the fuse melts, assisting the arc extinguishing process; the excellent ductility allows the copper outer cap to obtain a uniform wall thickness without cracking during stamping and deep drawing. For Copper End Caps Round and Copper Cap for Cylindrical Fuses, annealed (O-state) copper strips are usually used, which have lower hardness and higher elongation and are suitable for deep drawing forming. For Copper Cap High Pressure OEM and Copper Outer End Cap for High Voltage Low Current EV Fuse, due to the need to withstand higher arc pressure and thermal shock, semi-hard (1/2H) or copper materials with trace alloy elements added (such as silver-copper alloy) are sometimes selected to maintain high conductivity while improving creep resistance and softening resistance.

 

For Welding Fuse Copper Pipe End Cap, the material selection also needs to consider the welding compatibility with the pipe body material. When the pipe body is brass or stainless steel, the welding parameters of the copper end cap need to be adjusted accordingly to avoid the brittle phase produced by the welding of dissimilar metals. For Copper End Cap Solder Fittings, the end cap surface is usually pre-tinned or pre-fluxed to facilitate soldering assembly by downstream customers. In terms of surface treatment, the copper outer cap can be tin-plated, silver-plated or anti-oxidation passivated. The tin-plated layer can significantly improve the welding performance and prevent oxidation and discoloration of the copper substrate, while the silver-plated layer is used for high-end fuse products that require extremely high conductivity. For Copper Outer Cap for Industrial Power Fuse, considering the corrosive gases that may exist in the industrial environment, a sealing layer treatment is usually added after tin plating to pass the more stringent salt spray test requirements.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The manufacturing process of the copper outer cap is based on multi-pass deep drawing (Deep Drawing). The typical process flow is as follows: Step 1: Material preparation – Slit the copper strip (usually 0.5 mm- 2.0 mm thick) to the required width, and clean it to remove surface oil and oxides. For the mass production of Copper End Caps Round, automatic coil feeding is usually used to complete multiple processes in a continuous mold. Step 2: Blanking and drawing – The circular blank is punched out from the copper strip through a stamping die, and then multi-pass drawing is performed. Due to the limited elongation of copper, the amount of single stretching deformation cannot be too large (usually controlled at 40%-60%), so it is necessary to go through 3-6 stretching processes to gradually stretch the flat blank into a cylindrical part with a bottom. An intermediate annealing step may be required between each stretch to eliminate work hardening and restore material plasticity. For pipe caps with openings at both ends, such as Welding Fuse Copper Pipe End Cap, a bottom punching process is also required. Step 3: Trimming and shaping – There may be unevenness or burrs at the mouth of the stretched copper outer cap. The excess part needs to be cut off using a trimming mold and the mouth must be smooth. For Copper End Cap Solder Fittings, the shaping process also requires pressing out solder grooves or positioning steps on the inside or end face of the end cap to facilitate accurate positioning of the solder during subsequent assembly.

 

Step 4: Cleaning and deburring – Use ultrasonic cleaning or chemical degreasing to remove the stamping oil remaining during the stretching process, and remove tiny burrs through roller polishing or vibration grinding. For Copper Outer End Cap for High Voltage Low Current EV Fuse, a high-pressure water jet or electrolytic deburring process is often added as high-voltage applications are extremely sensitive to burrs. Step 5: Surface treatment – ​​tin plating, silver plating or anti-oxidation passivation treatment according to customer requirements. The thickness of the tin plating layer is usually controlled at 2-8 microns, and it is required to be uniform and dense, with no blistering and no missing plating. For Copper Cap for BS Type Fuse and Copper Outer Cap for Industrial Power Fuse, the coating needs to pass the neutral salt spray test for 48-96 hours. For Copper Outer Cap for Eaton Bussmann Fuse, the plating also needs to meet solderability test requirements - it should be fully wettable by solder at the specified temperature and time. Step Six: Inspection and Packaging – Conduct appearance inspection, dimensional measurement, coating thickness inspection and weldability spot inspection on the finished product. Automated optical screening equipment is used to fully inspect batches of products, and products with out-of-tolerance dimensions or surface defects are eliminated. Qualified products are packaged according to anti-collision requirements, usually using blister trays or anti-collision packaging.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The main application industries of copper outer caps are concentrated in electric vehicle manufacturing, fuse production and industrial power distribution. In the electric vehicle industry, Copper End Caps for EV Fuse is one of the core accessories of high-voltage fuses for new energy vehicles. The high-voltage battery pack of electric vehicles (voltage is usually 400V-800V, and some platforms have reached 1000V) requires fuses to quickly and reliably break DC current in the event of a short-circuit fault. As the end seal of the fuse, the copper outer cap not only bears the function of electrical connection, but also needs to withstand the impact of high-temperature and high-pressure gas generated during the breaking process. The high-voltage circuit of each electric vehicle usually contains 5-10 high-voltage fuses of different specifications, and accordingly requires the same number of copper outer caps. In the fuse manufacturing industry, Copper Outer Cap for Eaton Bussmann Fuse and Copper Outer Cap for Industrial Power Fuse represent the different requirements for copper outer caps of passenger car grade and industrial grade fuses, respectively - the former pays more attention to dimensional accuracy and surface cleanliness, while the latter pays more attention to mechanical strength and environmental corrosion resistance.

 

In the field of industrial power distribution, Copper Cap for BS Type Fuse and Copper Outer Cap for gG gL Fuse are widely used in factory distribution cabinets, building electrical systems, and mechanical equipment control cabinets. These scenarios require the copper outer cap to have good solderability and anti-oxidation ability under long-term use. In addition, Copper Cap for Cylindrical Fuses is also used in over-current protection of electronic equipment, power adapters and instruments. Its small size and large batch size put forward high requirements for production efficiency and size consistency. Copper Outer End Cap for High Voltage Low Current EV Fuse is an emerging demand that has emerged with the popularization of 800V high-voltage platform electric vehicles. Especially in high-end models that require fast charging, there are more stringent assessment standards for the voltage tolerance and long-term reliability of the fuse outer cap.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

We provide a one-stop service for Copper End Caps for EV Fuse from material selection, multi-pass deep drawing mold design, precision stamping to tin/silver plating surface treatment. The engineering team can quickly complete the solution design according to your assembly process and welding requirements. Welcome to submit drawings or samples for process evaluation and sample docking.