Button Cell Battery Guide: CR2450 CR2477 CR3032 & A312 A675 Hearing Aid Battery

Button Cell Battery Guide: CR2450 CR2477 CR3032 & A312 A675 Hearing Aid Battery

1. What is a Button / Coin Cell Battery Button cell (also known as coin cell) is a flat, disc-shaped primary battery, widely used for low-current, long-standby electronic equipment.

The naming rule: Prefix = chemistry system, numbers = dimension. First two digits = diameter (mm), last two digits = thickness (0.1 mm). For example: CR2477 means 24.5 mm diameter, 7.7 mm thickness, lithium manganese dioxide chemistry.

2. Main Chemistry Types & Core Specs Performance, open-circuit voltage and shelf life depend on internal chemistry. Mixing different battery types is a common procurement mistake.

Lithium Manganese Dioxide (CR) Voltage: 3.0V Capacity: CR2450:550mAh, CR2477:1000mAh, CR3032:550mAh Shelf Life: 5–10 years Feature: Ultra low self-discharge, wide temperature range Models: CR2450, CR2477, CR3032

Unlike rechargeable cylindrical lithium cells such as 18650, most coin cells are non-rechargeable primary cells. They are designed for micro low-power loads instead of high continuous discharge applications. NACCON’s main CR product line includes CR2450, CR2477, CR3032, which are large-size high-capacity 3V lithium coin cells. Meanwhile, zinc-air types A312 and A675 are specially made for hearing aids.

Zinc Air (PR / A series) A312 Voltage:1.45V, A675 Voltage:1.4V Capacity: A312:155mAh, A675:155mAh Feature: High capacity for hearing aid, air-activated Shelf Life: Short once activated after opening Models: A312, A675

Important reminder: CR series is 3V lithium coin cell, zinc-air A series is 1.4/1.45V. They cannot replace each other directly. Wrong voltage will burn out your PCB and circuits. Zinc-air batteries start working once the sealing tab is peeled off, their service life begins counting after opening.

3. How To Read Button Cell Model Code

4. Prefix: CR = Li-MnO₂ Lithium; A/PR = Zinc Air

5. Number sequence: Diameter + Thickness

   • CR2450: Dia 24.5 mm, Thickness 5.0 mm

   • CR2477: Dia 24.5 mm, Thickness 7.7 mm

   • CR3032: Dia 30.0 mm, Thickness 3.2 mm

6. A-series code: A312 = PR41; A675 = PR44, industry standard hearing aid battery size code

7. Capacity & Discharge Current The capacity unit of coin cells is mAh. Larger volume usually brings higher capacity. CR2477 is the highest-capacity option in this NACCON lineup, around 1000mAh.

Key knowledge All CR and zinc-air coin cells are low-rate discharge cells. They only support tiny continuous current and short pulse current. Do not select coin cells for heavy continuous loads; otherwise voltage will drop rapidly and the device cannot work normally. Energy calculation formula: Wh = V × Ah, used to compare energy between different batteries.

5. Button Cell Pack Configuration S&P rule is the same as lithium battery packs:

• S = Series: Raise total voltage, capacity unchanged Example: 2S CR2450 → 6.0V

• P = Parallel: Raise total discharge capacity and current, voltage unchanged Example: 2P CR2477 → 3.0V, 2000mAh

Special notes for coin cell packs

1. Coin cell internal resistance is relatively high. Cells must be matched by OCV and internal resistance before assembly. Mismatched cells cause early failure.

2. Standard CR / zinc-air packs usually do not come with BMS. Add protection circuit and NTC temperature sensor if multi-series design is required.

3. Soldering temperature control is critical. Excessive heat will damage sealing and cause leakage.

4. Charging Reminder CR lithium manganese dioxide coin cells and A-series zinc-air batteries are primary disposable batteries. NOT rechargeable. Trying to charge them will lead to leakage, swelling or even explosion. Only LIR series (such as LIR2032) are rechargeable coin cells. It is an independent product line and cannot replace CR cells.

5. Typical Application Scenarios

• CR2450 / CR2477 / CR3032 (3V Li-MnO₂): Smart door locks, remote controls, industrial sensors, car key fobs, water meters, circuit board backup power, medical monitoring equipment

• A312 / A675 Zinc Air: Digital hearing aids, cochlear implants

8. Safety, Compliance & Export Certification Coin cells are strictly controlled goods for cross-border shipment. Different chemistries belong to different UN classes:

9. CR lithium coin cell: UN3090 Lithium metal cell, comply with IATA air shipping regulations

10. Zinc-air hearing aid battery: Non-dangerous goods, but need to follow EU Battery Regulation EU 2023/1542 and US child-safe packaging standard 16 CFR 1263

11. Safety risks: Risk of ingestion by children, short circuit, extrusion and high temperature. Isolate single cells during storage to avoid short circuit. Warning labels are mandatory for USA and EU markets.

12. How to Select The Right Button Battery

13. Confirm device rated voltage → choose 3.0V CR or 1.4/1.45V zinc air

14. Confirm housing space, confirm diameter and thickness

15. Confirm load type: long standby low power or pulse signal transmission

16. Confirm storage requirement: long shelf life choose CR (low self-discharge)

17. Confirm destination country, prepare certification, warning label and child-safe packaging

18. Confirm customization: solder tabs, leads, terminals or assembled battery packs

19. FAQ Q1: Can CR2450 replace CR2477? A: No, same 3V voltage but different thickness and capacity, they cannot fit the same battery holder.

Q2: Can I use CR lithium coin cell to replace A675 hearing aid battery? A: Not allowed. Voltage, discharge curve and internal resistance do not match, it will damage hearing aid.

Q3: Can I make high-voltage packs with CR coin cells? A: Technically yes, but coin cells are not suitable for high-current loads, only recommended for low-power backup applications.

Q4: What is the shelf life of NACCON CR series? A: Up to 10 years under proper storage, annual self-discharge rate below 1%.

Conclusion Coin cells are compact and reliable power sources for micro electronics. Selection cannot depend only on appearance size. Chemistry, discharge performance, compliance and safety risks are all critical factors for buyers. NACCON supplies a full portfolio including large-capacity CR coin cells and mercury-free zinc-air hearing aid batteries, supporting OEM custom tabs, wires and battery packs for global customers.