Customer Need
A domestic energy storage system integrator (Company C) won a 2MWh commercial & industrial storage project requiring 20 outdoor storage cabinets. Each cabinet includes:
1. Sheet metal enclosure: 1800×800×800mm, 2.0mm galvanized steel, IP54, outdoor powder coating (RAL 7035).
2. Machined connectors: Silver‑plated T2 copper busbar terminals, 6061 aluminum battery module brackets (±0.05mm), Q235 steel inverter mounting base (black oxide).
Pain Points
Inconsistent bending angles from previous supplier → uneven gaps when cabinets were joined, affecting sealing and appearance.
Excessive contact resistance on copper terminals → local overheating, safety risk.
Hole misalignment between machined brackets and sheet metal cabinet → extensive on‑site rework, delaying installation.
Required 20 cabinets + components within 45 days – existing model could not meet the deadline.
Tightened bending tolerance on joining faces to ±0.2mm; added locating pin holes for alignment.
Optimised copper terminal design – increased contact area; precision turning + silver plating; contact resistance <0.1mΩ.
Unified datum; added slotted holes to absorb accumulated tolerance.
Sheet metal: Fibre laser cutting, press brakes with real‑time angle feedback, robotic MIG welding, post‑weld stress relief annealing.
Machined parts: Mill‑turn for copper terminals; 4‑axis machining for aluminum brackets.
Pre‑assembly: First cabinet assembled with all machined parts to verify hole fit and contact resistance.
Sheet metal: 100% inspection of joining face flatness, bend angles, coating thickness (80‑120μm), adhesion.
Copper terminals: 100% contact resistance (micro‑ohmmeter) and silver thickness (≥5μm).
Provided PPAP package (control plan, CPK report, material certificates).
Locked 8 hours/day dedicated laser cutting & press brake capacity for Project C.
Double shifts for machining workshop.
|
Metric |
Customer expectation |
Actual |
|
Lead time |
45 days |
38 days (7 days early) |
|
Cabinet joint gap |
≤2mm |
≤0.8mm – uniform |
|
Copper terminal contact resistance |
<0.15mΩ |
Avg. 0.08mΩ – no heating |
|
On‑site hole rework rate |
30% expected |
0% – direct fit |
|
IP rating |
IP54 |
Passed IPX5 rain test |
Company C passed customer acceptance ahead of schedule and received a project bonus.
Second phase (5MWh) directly renewed with double the order value.
Company C signed a blanket agreement with estimated annual spend of RMB 8‑10M.
Joint development of standardised storage cabinets – now C’s standard product.
We provide VMI consignment stock – C pays only when parts are consumed.
When machining and sheet metal are managed separately, mismatched lead times and hole misalignment are the biggest headaches. This supplier got involved from the design stage and treated both processes as one product. Delivering 20 cabinets in 38 days with zero on‑site rework is exceptional in the energy storage industry. They are now our strategic supplier.
OUR SERVICES
