A coin cell on a PCB can be held by a snap-in holder, attached with a pre-welded solder tab, or mounted directly through reflow. Each option has a different total cost (cell + assembly + service), and the right choice depends on whether the device is opened over its life.
Option 1: Snap-in holder
A plastic-or-metal socket that the coin cell drops into. Standard part numbers like Keystone 1066 (CR2032 holder) or Linx BAT-HLD-001. The cell can be replaced by the end user.
Pros: Standard part, $0.10 to $0.40 per holder. End user can swap the cell. Through-hole or SMD versions available. Survives reflow without the cell installed (cell goes in after assembly).
Cons: Higher contact resistance (typically 5 to 30 mΩ vs < 1 mΩ for welded). Vibration can disengage the cell unless the holder is keyed or retained. Adds 2 to 4 mm of board height. The holder's own quiescent leakage is small but not zero.
Use when: The end user is expected to replace the cell; the device is opened during normal life; service centres need to swap cells without rework equipment.
Option 2: Pre-welded solder tab
The coin cell ships with two nickel or copper tabs spot-welded to the can. The tabs are then soldered to the PCB in a pre-production assembly step. Common in legacy designs.
Pros: Low contact resistance (< 1 mΩ). Cell is mechanically retained against the board. No socket cost.
Cons: Cell cannot be replaced without rework. Increases assembly cost (manual hand-soldering after main reflow, or selective wave soldering). Tab fatigue in vibration environments unless the tab is supported.
Use when: The device is sealed, but reflow-mounting is impossible (LIR cells, or product has heat-sensitive components nearby); a single hand-solder station in production is acceptable.
See our coin cell tab welding guide for the full process, materials and reliability data.
Option 3: SMD reflow mount
The coin cell (ML2032 or ML2430 only — LIR cannot reflow) goes through the standard SMT line as a pick-and-place component. Pads on the PCB; cell on a tape-and-reel feeder; through reflow oven once.
Pros: Lowest assembly cost — no separate manual step. Lowest contact resistance (< 0.5 mΩ). Tightest mechanical retention. Smallest board area (no holder body).
Cons: Cell must survive 260 °C peak reflow — only ML cells qualify. Cell cannot be replaced, period. One reflow pass per cell only (no double-sided board with cell on the second side). Higher cell cost (ML at $0.80 to $2.20 vs holder + CR/LIR at $0.40 to $0.90 combined).
Use when: The device is sealed for life and the cell capacity is enough for 5+ year operation; high-volume program where assembly cost dominates BoM.
See our reflow profile guide for the J-STD-020 envelope ML cells tolerate.
Decision matrix
| Question | Holder | Solder tab | SMD |
|---|---|---|---|
| Does the user replace the cell? | ✓ Yes | ✗ No | ✗ No |
| Is the device sealed for life? | ✗ No | ✓ Yes | ✓ Yes |
| Can ML chemistry meet runtime? | n/a | n/a | Required |
| Vibration / shock environment? | Holder must be keyed | Tab support needed | ✓ Best |
| Lowest assembly cost? | Mid | Highest | Lowest |
| Highest production volume? | OK | Avoid | ✓ Best |
| Service / repair needed? | ✓ Easy | Difficult | Impossible |
The two patterns we ship most often
Holder + LIR2032: smart accessory devices where the user might replace the cell once over the device's life (typical: smart card with battery, BLE tracker with USB-C charge, smart pen). Holder cost is justified by occasional service swap.
SMD + ML2032: sealed-for-life products with 5+ year battery target (typical: BLE beacon, RTC backup on industrial PCB, smart-meter calibration retention). Lowest total cost when you amortise assembly cost across the production run.