Film capacitor adaptation: EV capacitor busbar performance improvement tips

According to the China Association of Automobile Manufacturers, China's new energy vehicle (NEV) sales reached 6.8 million units in H1 2025, up 35% year-on-year. Film capacitors are key for NEV power systems, but their performance depends on matching EV capacitor busbar. This article explores core tips to improve busbar performance, effect verification, adaptation notes, application fields, and Xiamen APOLLO's solutions.

 

 

1. Optimize Conductive Material Selection​

A busbar for power capacitor should use 99.99% oxygen-free copper. This material has conductivity ≥98.5% IACS, 5% higher than ordinary copper. It reduces current loss during transmission, ensuring film capacitors output stable power.​

 

2. Design Low-Inductance Structure​

A capacitor laminating bus bar adopts a layered layout (copper foil + insulation film). Control layer spacing at 0.1-0.2mm and use symmetric routing. This lowers inductance to ≤6nH, avoiding voltage spikes that damage film capacitors.​

 

3. Strengthen Insulation Protection​

Coat the busbar surface with modified epoxy resin (thickness 0.3-0.5mm) that meets GB/T 11022 standards. The coating resists breakdown voltage ≥40kV/mm, preventing short circuits between the busbar and film capacitor terminals.

 

 

1. Conductive resistance test: Measure EV capacitor busbar resistance under 25℃. A value ≤0.03mΩ/m means the busbar has low current loss-consistent with film capacitor's high-efficiency requirements. Test method refers to GB/T 3048.4-2023.​

 

2. Vibration durability test: Fix automotive power busbar with film capacitors on a vibration platform. Apply 10-2000Hz sine wave vibration for 10,000 cycles. No loose connections or insulation damage proves stable performance in NEV driving.​

 

3. Temperature cycle test: Cycle the busbar between -40℃ (low temperature) and 125℃ (high temperature) for 2000 times. Each cycle lasts 30 minutes. No performance degradation shows it adapts to NEV's harsh temperature changes.

 

 

Such busbars and matching film capacitors are widely used in NEV power systems. In NEV drive inverters, automotive power busbar transmits 300-600A current, ensuring inverters convert DC to AC stably. In NEV battery management systems (BMS), a busbar for power capacitor balances battery cell voltages, protecting film capacitors from overvoltage damage. In industrial frequency converters (used in EV manufacturing lines), capacitor laminating bus bar adapts to high-power film capacitors, improving converter's load capacity. These fields all rely on optimized busbar performance.

 

 

Xiamen APOLLO's EV capacitor busbar uses 99.99% oxygen-free copper and imported epoxy insulation. It has inductance ≤5nH and resistance ≤0.025mΩ/m-15% better than industry averages. It passes conductive resistance, vibration, and temperature cycle tests, meeting ISO9001-2015, IATF16949, ROHS, REACH, as well as GB and UL standards. Our product range covers capacitor laminating bus bar and automotive battery terminal bus bar to fit different film capacitor models.​

 

We offer custom services: adjust busbar size (length 50-1200mm, width 10-80mm), terminal pitch (5-50mm), and insulation thickness for NEV or industrial scenarios. Our global logistics includes air (3-5 days to Asia), land (7-15 days to neighboring regions), and sea (15-20 days to Europe/America). Our 24-hour after-sales team provides on-site adaptation guidance and performance testing, ensuring perfect matching with film capacitors.