1-Slot 21700 Lithium-Ion Battery Holder (SMD / Surface Mount)

Specifications

• Battery Compatibility: 1x 21700 Cylindrical Cell

• Mounting Style: Surface Mount Device (SMD / SMT)

• Contact Material: Nickel-Plated Steel / Phosphor Bronze

• Housing Material: High-Temperature Resistant Plastic

• Negative Contact: Spring tension with 9-dimple grip pattern

• Positive Contact: Solid plate with circular contact node

• Output Voltage: 3.7V (Nominal)

Key Applications and Projects

• Custom Power Banks: Designing a high-capacity, single-cell emergency phone charger PCB.

• High-Drain Flashlights: Creating a custom driver board for extreme-output LEDs that require the massive current delivery of a 21700 cell.

• IoT Sensor Nodes: Powering remote, solar-recharged environmental monitors where a single 21700 cell provides months of standby time.

Unlock New Capabilities (Project Evolution) The Hot-Swappable Drone Base Station: Don't limit your projects to built-in, non-replaceable batteries! Design a custom PCB that utilizes four of these SMD holders wired in a 4S (series) configuration. Because the holders are SMD, the back of your PCB remains perfectly flat, allowing it to be mounted flush against a drone charging station chassis. You now have a high-power, hot-swappable battery management system where depleted 21700 cells can be popped out and replaced instantly to keep your equipment running continuously!

PACKAGE INCLUDED

• 1 x 1-Slot 21700 Cell Lithium Ion Battery Holder (SMT/SMD)

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What specific battery size does this holder accept? It is engineered exclusively for standard 21700 cylindrical lithium-ion cells.

2. What do the numbers "21700" mean? They represent the physical dimensions of the battery: approximately 21mm in diameter and 70mm in length.

3. Can I use an 18650 battery in this holder? No, an 18650 battery (18mm diameter, 65mm length) is too short and too narrow; it will not make electrical contact or be held securely.

4. How does this attach to a circuit board? It uses Surface Mount Technology (SMD). You apply solder paste to pads on your PCB and solder the flat metal tabs that extend from the bottom of the holder.

5. Are there any through-hole pins on the bottom? No, the bottom of the contacts are completely flat tabs designed exclusively for surface mounting.

6. Will this hold protected 21700 cells? Usually no. Protected 21700 cells have an internal protection circuit that adds 3-5mm to their length. This holder is strictly dimensioned for standard, unprotected 70mm cells.

7. Can this holder withstand reflow soldering temperatures? Yes, SMD battery holders are typically molded from high-temperature plastics (like LCP or PPS) designed to survive standard reflow oven temperature profiles.

8. Why are there dots on the negative contact? The negative spring contact has a grid of dimples to increase physical friction and penetrate any minor oxidation on the battery terminal, ensuring a low-resistance connection.

9. How do I identify the positive end? The positive end features a flat metal plate with a single, pronounced circular protrusion designed to touch the positive cap of the battery.

10. Can I wire these in series or parallel? The holder itself is just a physical socket. You configure series or parallel connections by routing the copper traces on your custom printed circuit board.

11. Is there a bottom to the plastic housing? The bottom is mostly open, featuring a large cut-out slot. This saves space, allows the battery to sit closer to the PCB, and aids in heat dissipation.

12. Does this holder provide battery protection? No, this is a purely mechanical and electrical pass-through component. Over-charge and over-discharge protection must be handled by an external BMS chip on your PCB.

13. What voltage will this holder output? It will output whatever voltage the inserted battery provides, which is typically 3.7V nominal (4.2V fully charged) for a standard Li-ion cell.

14. What is the maximum current rating? While the exact rating depends on the PCB trace width and solder joint quality, standard SMD 21700 holders with these types of contacts typically support 5A to 10A of continuous current.

15. Is it safe for high-vibration applications like RC cars? Surface mount solder joints can be stressed by heavy vibration. For high-impact applications, it is recommended to add a strap or enclosure to secure the heavy 21700 battery, taking physical stress off the solder tabs.

16. Can I use LiFePO4 21700 cells in this? Yes, physically it will hold any 21700-sized cell perfectly, regardless of the internal chemistry (Li-ion, LiFePO4, etc.).

17. Do I need to buy batteries separately? Yes, this listing is for the plastic and metal holder only. Batteries are not included.

18. How do I remove a battery from the holder? Simply push the battery against the dimpled negative spring contact to compress it, then lift the positive end out of the open top.

19. What does the text on the side say? The side molding indicates "SMT/THM FOR 21700X1", confirming its intended use for a single 21700 battery.

20. Can I hand-solder this instead of using a reflow oven? Yes. Because the SMD tabs extend slightly outward from the plastic body, they are accessible with a standard soldering iron tip, making hand-soldering onto PCB pads very straightforward.