Nickel-plated busbar: a key role in new energy hardware materials
Feb 08, 2025
product definition
Nickel-plated busbar refers to a composite conductive component in which a layer of metallic nickel is deposited on the surface of a copper or brass busbar through an electroplating or chemical plating process. Its core structure is a highly conductive copper matrix closely combined with a surface nickel layer, which not only retains the excellent current-carrying capacity of copper, but also greatly improves the busbar's corrosion resistance, wear resistance and oxidation resistance in high-temperature environments through the chemical inertness and high hardness of the nickel layer. Compared with tin-plated busbars, the outstanding advantage of nickel-plated busbars is that the nickel layer can withstand higher operating temperatures (long-term operating temperatures can reach over 250°C, while the tin layer will soften and oxidize when it exceeds 120°C). Therefore, it is particularly suitable for high-temperature working conditions or electronic assembly processes that require reflow soldering. In terms of product form, Nickel-Plated Bus Bar is a common name in the industry and is suitable for nickel-plated busbars of various cross-sectional shapes (rectangular, circular or special-shaped); Nickel Plated Copper Busbars emphasize that its material is a copper substrate, which can be clearly distinguished from nickel-plated aluminum busbars or stainless steel substrate products. In the field of power electronics and switching equipment, Nickel Plated Bus Bars are often used to connect power modules, capacitors and input and output terminals. The uniformity and denseness of the nickel layer directly determines the long-term stability of the contact resistance.
Application industry
Nickel-plated busbars have extensive and irreplaceable applications in high-end industrial fields such as new energy, power electronics, communication equipment, and aerospace. In the electric drive system of new energy vehicles, the power module (IGBT or SiC) in the motor controller generates a large amount of heat when working, and the ambient temperature of the busbar connection row may be as high as about 150°C. If tinned busbars are used, the tin layer will accelerate oxidation and even melt and flow at this temperature, causing the contact resistance to rise sharply. The nickel layer of Nickel Plated Copper Busbars remains stable at this temperature, and its surface oxidation rate is extremely slow, which can ensure the long-term reliability of the connection between the power module and the DC support capacitor. In addition, in on-board chargers (OBC) and DC-DC converters, busbars often need to be assembled with printed circuit boards through a reflow soldering process. The peak temperature of reflow soldering can reach 260°C. Only Nickel Plated Bus Bars can withstand this thermal shock without discoloration of the plating or loss of solderability.
In the field of power transmission and transformation, the ground busbars and main busbar connectors in gas-insulated metal-enclosed switchgear (GIS) and high-voltage switch cabinets have been in a sealed environment of high voltage, high current and a certain temperature for a long time. Nickel Plated Copper Flat Bus Bar relies on its excellent corrosion resistance and fretting resistance to effectively prevent coating wear and matrix corrosion on the contact surface under long-term vibration or thermal cycling. For the primary contacts of drawer-type switch cabinets that require frequent plugging and unplugging, Flat Bar Red Pure Copper Nickel Plating's hard nickel layer (hardness is about 5 to 8 times that of the tin layer) can withstand hundreds of plugging and unplugging without obvious signs of wear, ensuring the self-cleaning function and contact stability of the contacts. In the field of new energy storage, high-voltage connection rows and bus copper bars between battery clusters, because energy storage containers may be installed near coastal beaches or chemical industry parks, salt spray and corrosive gases in the air will cause serious corrosion to bare copper or tin-plated busbars. The nickel layer of Standard Nickel Plating Flat Busbar has high density and low porosity (typical value ≤ 1 pore/cm²), which can effectively block the penetration of corrosive media. The salt spray test can achieve neutral salt spray for more than 500 hours without red rust.
Manufacturing process
The manufacturing process of nickel-plated busbars can be divided into three main stages: busbar machining, surface pretreatment and nickel electroplating. The starting point of the process is the shaping of the busbar: copper strips or plates are processed into the shape specified by the customer through processes such as punching, sawing, bending, and drilling. At this stage, all edges must be chamfered or deburred (the chamfer radius is usually 0.5~1.5mm), because sharp edges will cause the coating to thicken abnormally due to the tip discharge effect during electroplating (forming "dog ear"-shaped nodules), and will become electric field concentration points in subsequent use, increasing the risk of partial discharge. The bending process must be completed before electroplating, because the nickel layer is brittle and bending will cause the plating to crack. After the mechanical processing is completed, the workpiece enters a strict pre-processing process. First, chemical degreasing is performed - soaking in a high-temperature alkaline solution for 10 to 20 minutes to remove stamping oil and fingerprints on the surface of the copper strip. Then rinse with pure water two to three times. The second step is pickling and activation - soaking in 5~10% dilute sulfuric acid solution for 30~60 seconds to remove the natural oxide film on the surface of the copper row and expose the fresh copper matrix. Pure water rinsing must be carried out immediately after pickling to prevent acid residue. For complex-shaped parts in Nickel-Plated Bus Bars (such as with deep holes or deep grooves), an ultrasonic cleaning step is required to remove contaminants in hidden areas.
FAQ
Q: Will the nickel layer of nickel-plated busbars fade?
A: Not under normal use. The nickel plating layer is a metallic nickel deposition layer, not a dye or pigment, and there is no concept of "fading". However, if exposed to a sulfide-containing environment for a long time (such as near rubber seals), a gray-black nickel sulfide film may form on the surface. This is chemical discoloration rather than shedding. It can be partially removed with a silver-wiping cloth without affecting the conductive properties.
Q: Why do some nickel-plated busbars have yellow-brown stripes on their surfaces?
A: This is the "color difference between high and low electric areas" caused by the uneven distribution of current density during electroplating - the current density is high at the edges and corners of the busbar, and the coating is thicker and brighter white; the current density is low at the center of the plane or in the pits, and the coating is thinner and lighter yellow. This is a normal phenomenon in the electroplating process. As long as the thickness of the coating reaches the standard and the bonding strength is up to standard, the color difference will not affect the product quality.
Q: Can nickel-plated busbars be used in outdoor exposed environments?
A: It's OK in the short term, but not recommended in the long term. Nickel coatings gradually lose their luster and may develop pitting corrosion when exposed to UV rays, rain, and temperature cycles for extended periods of time outdoors. For outdoor applications, it is recommended to add a layer of clear sealer to the nickel layer or to use stainless steel-clad copper busbars instead. If nickel-plated busbars must be used and a life span of more than 3 years is required, the thickness of the nickel layer should be no less than 12 μm and anti-rust oil should be applied regularly.
Q: How to store a nickel-plated busbar? How long is the shelf life?
A: Store in a dry, cool room without acid and alkali gases, relative humidity ≤60%, temperature -10℃~40℃. As long as the original moisture-proof packaging is not removed, the shelf life is 12 months. It should be used within 7 days after opening or should be resealed and stored. Products that have exceeded the shelf life should be subjected to solderability testing (if welding is required) or contact resistance spot checks before use.
contact us
Whether you need extra-long Nickel plated Copper Bus Bar, special-shaped bent parts, or have strict requirements on nickel layer thickness or salt spray resistance level, our team of electroplating engineers and mold technicians can provide plating solution design and quotation based on your drawings and application environment.
