Custom Battery Pack Design

Start with the design inputs

Good pack design begins with the load, not the cell catalogue. The inputs we work from are: the device and application; the available space, ideally with a drawing or a sample of the current pack; the target voltage; the capacity, derived from your load current and the runtime you need; continuous and peak discharge current; the operating environment, including temperature range and sealing needs; and the target market, which decides which product documents the finished model needs. If some inputs are still open, send what you have — the evaluation step works through the rest with you.

Cell selection and configuration

With the inputs set, we select the cell format and chemistry that fit: 18650 or 21700 cylindrical cells for most equipment packs, pouch cells where shape freedom matters, LiFePO4 where thermal stability and cyclic service come first. Cells can be selected from established cell makers: Panasonic, Samsung, LG, Molicel, Murata, EVE and BAK for lithium-ion, and EVE and Great Power for LiFePO4. Series count sets the pack voltage, parallel count sets capacity, and both are checked against the current profile and the physical space before the specification is written.

BMS and protection design

Every pack design includes its protection and management circuitry. The BMS is matched to the configuration and the charge/discharge profile: over-charge, over-discharge and short-circuit protection as the baseline, with charge/discharge management and SOC/SOH monitoring where the application calls for it. Where the host system needs data from the pack, communication options — Bluetooth, WiFi, CAN bus and RS485 among them — are evaluated per project and confirmed in the specification. The design step is where these choices are fixed, because changing them after tooling or enclosure work starts is what makes projects slow.

Enclosure, leads and connectors

Mechanical design covers the enclosure form — soft-pack structures, heat-shrink covering or injection-molded housings — plus lead length, connector type and labelling. These details go on the confirmed drawing, so the sample you approve is the pack that production repeats.

Samples and verification

Samples are developed after the specification and drawings are confirmed. They are verified against the agreed test items, and the documentation needed for your target market is checked at the same stage: UN38.3, IEC 62133 and MSDS documents can be confirmed and provided for specific models. After sample approval, production, packaging, quantities, delivery and acceptance conditions are confirmed for the order. If you already have a pack design, we can also review it against its specification and test items as part of a project evaluation — send the design file and tell us what is not performing as expected.

Frequently Asked Questions

What design inputs do you need: voltage, current, size, runtime?

Those four, plus the device context. Voltage comes from your equipment; current means both continuous and peak discharge; size means the real available space, including connector clearance; runtime combines with load current to set capacity. The spec guide shows how each input is used.

How do you select cells and design the BMS?

Cells are selected on format, capacity, discharge capability and sourcing stability, then arranged in the series/parallel configuration your voltage and capacity require. The BMS is designed around that configuration and your charge/discharge profile, with protection functions as the baseline and monitoring or communication added where the application needs them.

Can you review our existing pack design?

Yes. Send the existing specification or design file and a note on the problem — short runtime, overheating, early failures, a compliance gap — and we will review the design against its specification and test items as part of the project evaluation, then propose a revised specification if the design needs to change.