Sodium-Ion Battery for Aluminum Extrusion Plant: Smoothing the Press, Holding the Line
Sodium-Ion Battery for Aluminum Extrusion Plant: Smoothing the Press, Holding the Line
An extrusion plant has one of the least forgiving electrical profiles in light industry. The press draws a sharp, repetitive peak every cycle, the billet heater adds a large steady block of demand on top, and the handling equipment in between is sensitive to any disturbance in the supply. Most operators first look at storage because of the demand charge those peaks generate, and then discover that the same bank quietly solves the outage problem as well. A sodium ion battery system suits this duty: high cycle counts at partial depth of discharge, stable behaviour in a hot hall, and a cost structure that works at industrial scale.
What an Extrusion Press Does to a Supply
The press cycle is short, sharp, and repeated hundreds of times a day. Hydraulic pumps ramp hard, hold, then drop away, and the supply sees a sawtooth that never settles. That profile is expensive twice over. It sets the monthly demand charge, because the utility bills on the highest interval in the period rather than on average consumption, and it stresses the upstream transformer and switchgear. It also makes any voltage dip worse, because equipment is already operating near its limits when the disturbance arrives. Measuring the cycle properly, with a logger fast enough to catch the ramp, is the first step in sizing anything.
Where the Money Actually Comes From
Peak shaving is usually the headline saving, and it is real: clip the top of each press cycle and the highest interval in the month drops, sometimes by enough to change the tariff band. But the second source of value is often larger and far less visible. A press that stalls mid-stroke can leave a billet solidifying in the container, and removing it is a manual, slow, and occasionally damaging job. Backing up the pump controls, the billet handling, the runout table, and the quench system means a disturbance costs a pause rather than a teardown.
Extrusion Plant Support Options
| Attribute | Sodium-Ion Bank | Lithium LFP Bank | Flywheel UPS |
|---|---|---|---|
| Cycle life at partial depth | Very high | High | Very high, seconds only |
| Peak shaving capability | Yes, minutes of discharge | Yes | No practical energy |
| Behaviour in a hot hall | Stable over wide range | Derate, needs cooling | Tolerant, mechanical |
| Footprint at industrial scale | Moderate | Compact | Large for energy |
| Upfront cost per kWh | Lower | Higher | High for the duty |
Cold Starts, Hot Halls, and Siting
Extrusion halls are hot, and the temperature near a billet heater or a ageing oven is hotter still. Sodium-ion chemistry holds its performance across a wider band than lithium-ion in that environment, which reduces the cooling burden and removes one more system that has to work. The flip side is energy density: a sodium bank will occupy more floor area for the same energy, so plan the siting early rather than trying to find room after the press has been commissioned. Keep it out of the direct radiant path of the heater, away from the quench water, and accessible for inspection.
What to Ask a Supplier
Ask how the control system decides when to discharge, because a peak-shaving controller that reacts too slowly will miss the ramp entirely and deliver none of the saving. Ask for the round-trip efficiency at the actual discharge rate you will use, not at a gentle laboratory rate. Confirm the cycle-life warranty at partial depth of discharge rather than at full cycles, and ask what happens to the warranty if the bank is called on for outage support as well as daily shaving.
People Also Ask
Can storage really cut the demand charge on a press? Yes, if the controller is fast enough to catch the ramp and the bank is sized for the peak rather than the average. Model it against a year of interval data before committing.
What happens to a billet if the press stops mid-stroke? It cools and solidifies in the container. Removing it is slow manual work and can damage the liner, which is why ride-through is worth specifying.
Why choose sodium over lithium in a hot plant? Sodium cells hold performance across a wider temperature band, so the cooling and derating burden is lower, and the cost per kilowatt-hour is generally better at industrial scale.
How much floor space does an industrial bank need? More than an equivalent lithium system, because sodium cells are less energy dense. Decide the location during layout, not after commissioning.
Written by Karl at China Battery Technology. Request a quote.
