In energy storage component sourcing, the biggest savings often come from how a part is made — not from negotiating the price of the part you were handed.
A client came to me with a clear request: source this energy storage connection terminal from China, and get me the best price you can. Attached was a drawing of the terminal they’d been using for years — a proven, older design they trusted.
Most sourcing jobs begin and end there. You take the drawing, shop it to qualified suppliers, push on price and report back. I didn’t stop there, because the part the client asked me to buy was costing them money in a place no amount of negotiation could reach.
Why the legacy terminal cost too much
The legacy design: a copper conductor CNC-machined from solid bar. Proven, but machining-heavy.
The problem wasn’t the supplier, and it wasn’t the negotiation — it was the part itself. The older design was machined from solid stock: the copper conductor was cut from bar, turned on a CNC lathe for its outer diameter and steps, then drilled, tapped for the internal thread, milled for its flats and side holes, chamfered, deburred, surface-treated and assembled — eight operations in all, with roughly five minutes of machining per piece. A good share of that copper bar ended up as chips on the floor. Every unit carried those machining minutes, and that wasted metal, before it ever left the line.
You can negotiate a machined part down a few percent. You cannot negotiate away the operations the design forces onto the shop floor. The client wasn’t overpaying because they’d picked a bad supplier; they were overpaying because the part was expensive to make — and quote-shopping doesn’t change that.
A functionally identical terminal, made a smarter way
The replacement: a formed copper busbar — flat bar cut, punched, bent and press-riveted. Same job, far less machining.
There was a better option: a newer terminal, functionally equivalent for the client’s application, built as a formed copper busbar rather than a machined part. Instead of carving the conductor out of solid bar, this design starts from flat copper stock that is cut to length, punched, bent to shape and finished with a press-riveted nut. Fewer demanding operations, far less machining and almost none of the copper lost as scrap.
Instead of simply quoting the old part, I brought the client the alternative. Per-piece production time dropped from around five minutes to about two — roughly 60% — and because machining time was the main cost driver, the unit cost fell with it, by about 30%. Less copper is wasted, and the simpler process scales more easily.
One clarification, because it’s what buyers worry about most: this was not “cheaper because it’s worse.” The electrical and mechanical performance the application requires is fully met. What changed was the manufacturing route — not the quality.
Lean manufacturing, applied to sourcing
What happened here is textbook lean production — the discipline the Toyota Production System built around eliminating muda, the waste that adds no value: over-processing, unnecessary operations, long setups, excess motion and scrap. The legacy terminal had that waste designed into it. The newer one was designed to be made efficiently from the start.
So the cheapest part isn’t the one you negotiate hardest on. It’s the one engineered to be produced without waste in the first place. Price negotiation works at the margin; process and design work on the whole cost.
The blind spot in most component sourcing
Here’s the gap many storage companies fall into. When you hand a supplier a drawing and ask for a quote, you learn exactly one thing: what that part costs. You don’t learn whether a smarter part exists — and the supplier has no reason to talk you out of an order you’re already placing.
That blind spot — between quoting what you asked for and knowing what you should be asking for — is where the real sourcing value lives. The job isn’t relaying a drawing and forwarding a number back. It’s looking at the spec, the bill of materials and the way the part is actually built, and asking whether you’re buying the right thing at all. In this case, that single question saved the client real money on every unit, for the life of the program — far more than haggling over the original part ever could have.
For anyone sourcing ESS components — terminals, busbars, brackets, enclosures — the practical takeaway fits in three questions. Ask your supplier what the process route is, not just the price. Ask whether the same function can be achieved with a formed, stamped or extruded part instead of a machined one. And when a quote comes back high, ask where the cost actually lives — material, machine time or waste — before assuming the answer is a harder negotiation.
The drawing you send out defines the ceiling of your savings. Sometimes the best sourcing decision is to question the drawing itself.
Quanyu Qiu is the founder of Canton Qwen, a buyer-side China sourcing firm based in Guangzhou. He helps overseas buyers with factory visits and order-based China sourcing across a broad range of product categories, with his strongest hands-on experience in energy storage, solar PV and pig-farm equipment. He studied operations and supply chain management at the University of South Carolina’s Darla Moore School of Business and is trained in Lean Six Sigma methods.