Molicel 21700 P45B 4500mAh 45A Battery
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strong energy density. 45A Continuous Discharge 4500mAh Typical Capacity 16.2Wh Typical Energy 13.5A Max Charge 3.6V Nominal Voltage Unprotected Flat Top 45AContinuous Discharge, 80°C Cut-Off 4500mAhTypical Capacity 4300mAhMinimum Capacity 7mΩTypical AC Impedance 13.5AMaximum Charge, 70°C Cut-Off 21.55 × 70.15mmMax Cell Envelope Molicel 21700 P45B 4500mAh 45A Battery The Molicel P45B is a low-impedance 21700 power cell built for high-drain applications where a standard energy cell would experience too much voltage sag or heat rise. It improves on the classic 21700 power-cell category by pairing a 4500mAh typical capacity with a 45A continuous discharge rating and high fast-charge capability. The 45A continuous discharge rating is specified with an 80°C cut-off, and the 13.5A maximum charge current is specified with a 70°C cut-off. Final pack current should be validated under the actual cooling, enclosure, busbar, BMS, and load conditions. Brand / Model Molicel INR-21700-P45B Cell Series Molicel low-impedance power cell Cell Type 21700 cylindrical lithium-ion rechargeable cell Typical Capacity 4500mAh / 16.2Wh Minimum Capacity 4300mAh / 15.5Wh Nominal Voltage 3.6V Charge Voltage 4.20V Discharge Cut-Off Voltage 2.50V Standard Charge Current 4.5A Maximum Charge Current 13.5A with 70°C cut-off Thermal control required Standard Charge Time 1.5 hours Continuous Discharge Current 45A with 80°C cut-off Typical Impedance 7mΩ AC at 30% SOC; 15mΩ DC at 50% SOC Charge Temperature 0°C to 60°C Discharge Temperature -40°C to 60°C Energy Density 643Wh/L volumetric; 242Wh/kg gravimetric Dimensions 21.55mm max diameter × 70.15mm max height Weight 70g max Protection No — unprotected flat-top cell Electrical operating envelope at a glance. These quick-reference visuals summarize the P45B’s current capability, voltage window, energy translation, and C-rate interpretation. 1. Current Capability Stack Key current reference points for standard charge, maximum charge, data-sheet discharge curves, and continuous discharge rating. 45A 30A 20A 13.5A 4.5A Continuous discharge High-rate curve ref. Medium-rate ref. Max charge Standard charge Current (A) 2. Voltage Operating Window Basic per-cell voltage limits used for charger, BMS, and pack design. 2.5V 4.2V Usable operating band Discharge cut-off Charge cut-off Nominal cell voltage: 3.6V 3. Capacity and Energy Translation The data sheet lists 16.2Wh typical energy; nominal-voltage math gives a close planning estimate. Capacity 4.5Ah Voltage 3.6V Energy ≈16.2Wh Matches data-sheet typical energy × = 4. C-Rate Conversion For a 4500mAh cell, 1C equals approximately 4.5A. 0.9A ≈0.2C low-rate reference 4.5A 1C standard charge and cycle reference 10A ≈2.2C cycle / discharge reference 13.5A 3C maximum charge current with thermal cut-off 30A ≈6.7C high-rate discharge curve reference 45A 10C continuous discharge rating with 80°C cut-off High-current output should be evaluated with voltage sag, heat rise, and pack resistance in mind. The P45B data sheet includes discharge-rate curves at 0.2C, 1C, 10A, 20A, 30A, and 45A. The cell is rated for 45A continuous discharge, but the highest-current condition uses an 80°C thermal cut-off, so pack design must manage heat as much as current. The simplified discharge-curve graph below visualizes voltage versus delivered capacity under light, medium, high, and maximum-current conditions. It is not a digitized manufacturer graph; it is a product-page visualization designed to explain voltage sag and cutoff-limited capacity at higher current. Discharge-rate references 0.2C / 1C Low-rate and 1C curves shown in the data sheet 10A / 20A Medium-load discharge curve references 30A High-load data-sheet curve reference 45A Maximum continuous discharge curve reference with thermal cut-off condition Design takeaway For high-current packs, validate voltage sag and cell temperature under the actual enclosure, BMS, weld, and busbar design. 5. Simplified Discharge-Curve Graph Voltage vs. capacity illustration for 4.5A, 20A, 30A, and 45A operation. Simplified for product-page visualization. 4.2V 3.9V 3.6V 3.3V 3.0V 2.7V 2.5V 0 1000 2000 3000 4500 Capacity delivered, mAh Cell voltage 4.5A reference 20A high load 30A data curve 45A max cont. 6. Estimated IR Voltage Drop Planning reference using Molicel’s typical AC and DC impedance values. Real pack sag includes cells plus interconnects. V_drop ≈ I × R At 20A and 7mΩ AC reference: ≈0.14V estimated drop At 45A and 7mΩ AC reference: ≈0.32V estimated drop At 45A and 15mΩ DC reference: ≈0.68V estimated transient drop Welds, nickel, busbars, holders, wiring, fuses, BMS MOSFETs, temperature, age, and SOC all influence real voltage sag. Charge, discharge, and thermal behavior should be treated as one system. Molicel’s data sheet includes charge curves, discharge-rate curves, discharge-temperature curves, and cycle-characteristics curves. These visuals are condensed into customer-friendly diagrams below. 7. Charge Profile Reference Standard charge: 4.5A to 4.2V with 50mA cut-off. The data sheet also shows 2C and 3C charge characteristics. 4.5A standard CC stage CV hold @ 4.2V 50mA termination 13.5A max charge requires thermal control Voltage / current Charge time progression 8. Thermal Operating Envelope Published charge and discharge temperature ranges. Charge: 0°C to 60°C Discharge: -40°C to 60°C Upper charge limit Upper discharge limit High-current pack design should include temperature sensing and current derating. 9. Discharge Rate Characterization Customer-friendly summary of the data-sheet discharge-rate curve families. 0.2C / 1C 10A 20A / 30A 45A Capacity delivered Voltage 10. Discharge Temperature Characterization The data sheet charts 4.5A discharge behavior from -40°C through 60°C. -40°C -30°C -20°C 0°C 23°C 45°C 60°C Higher Lower Relative delivered capacity Test temperature 11. Cycle-Life Visualization Data-sheet cycle characteristics are shown for 4.5A, 10A, and 100W discharge at 23°C. 4.5A discharge 10A discharge 100W discharge 0 100 200 300 400 500 100% 80% 60% 40% Cycle count Capacity retention 12. Energy Density Summary Data-sheet energy density values for design comparison. Typical Energy 16.2Wh Minimum Energy 15.5Wh Volumetric Energy Density 643Wh/L Gravimetric Energy Density 242Wh/kg Design implication Strong energy for a high-power 21700, with low impedance and fast-charge support. 21700 dimensional envelope for holders, sleds, weld fixtures, and pack CAD. 13. Cell Dimension Diagram Mechanical envelope based on Molicel maximum dimensions. 70.15mm max 21.55mm max 21700 cylindrical steel-can cell with maximum envelope shown Confirm fit in holders, chargers, sleds, welded modules, and insulated pack fixtures. 14. Pack Scaling Formulas Quick math for series/parallel planning. Validate current limits thermally and electrically. Pack Voltage ≈ Series Count × 3.6V Pack Capacity ≈ Parallel Count × 4.5Ah Pack Energy ≈ S × P × 16.2Wh Cell-Level Current Capability ≈ Parallel Count × 45A 15. Example Parallel Scaling Approximate scaling using cell-level continuous discharge rating, not a finished-pack guarantee. 1P 4.5Ah, 16.2Wh, 45A cell-level current reference 2P 9.0Ah, 32.4Wh, 90A cell-level current reference 3P 13.5Ah, 48.6Wh, 135A cell-level current reference 4P 18.0Ah, 64.8Wh, 180A cell-level current reference 5P 22.5Ah, 81.0Wh, 225A cell-level current reference 16. Common Series Voltage Examples Nominal voltage examples only. Full-charge and cut-off pack voltages scale separately. 1S 3.6V nominal / 4.2V full / 2.5V cut-off 3S 10.8V nominal / 12.6V full / 7.5V cut-off 4S 14.4V nominal / 16.8V full / 10.0V cut-off 5S 18.0V nominal / 21.0V full / 12.5V cut-off 10S 36.0V nominal / 42.0V full / 25.0V cut-off 13S 46.8V nominal / 54.6V full / 32.5V cut-off Use the P45B inside a controlled electrical and thermal system. This is an unprotected high-power cell. Safe implementation requires a charger, BMS, fuse strategy, interconnect design, and thermal-management plan that respect the cell’s limits. 17. Suggested Control Threshold Map System-level control guidance derived from the live listing and Molicel data-sheet values. Charge upper limit 4.20V per cell Discharge floor 2.50V per cell Charge temperature gate 0°C to 60°C Discharge temperature gate -40°C to 60°C Standard charge 4.5A CC-CV to 4.2V, 50mA termination Maximum charge 13.5A with 70°C cut-off; validate thermally before use Continuous current 45A with 80°C cut-off, subject to system-level thermal and interconnect validation 18. Risk-Control Checklist Recommended pack-building and use practices. Use only in devices or packs designed for lithium-ion 21700 cylindrical cells. Use a BMS or controller that monitors voltage, current, and temperature. Do not charge above 4.20V or discharge below 2.50V per cell. Validate high-current operation under the actual enclosure, cooling, and load profile. Never carry loose cells with conductive objects such as keys, coins, tools, or metal cases. Spot weld for pack assembly; do not solder directly to the cell body. Inspect wraps and top insulator rings before use. Size busbars, nickel, fuses, wiring, and BMS MOSFETs for both electrical resistance and heat rise. Best suited for high-drain systems that need both power and usable capacity. Power Tools Strong option for tool packs requiring high current per cell. Low impedance helps reduce voltage sag under heavy tool loads. EV / Micro-Mobility Suitable for performance mobility packs with the correct BMS, fusing, and cooling. Parallel count should be based on measured current, voltage sag, and heat rise. Drones / eVTOL Useful for high-power airborne systems where current density matters. Thermal validation is essential under peak discharge profiles. Robotics / RC Supports high motor current and compact pack geometry. Useful where power response and moderate energy density are both important. High-Output Lighting Good fit for demanding LED systems that pull high current from each cell. Use only in devices designed for unprotected 21700 flat-top cells. Custom Battery Packs Designed for experienced builders and integrators who can manage current sharing and heat. Requires matched cells, correct welding, insulation, protection electronics, and pack-level testing. 19. Selection Bias: Power vs. Runtime Product-page positioning for shoppers comparing high-power and high-energy cells. More runtime per cell → More power / current → Molicel P45B High-power 21700 with strong energy density Higher-capacity energy cells typically sit further right 20. Application Suitability Matrix Simple product-page fit guidance. Power tools Strong fit Drones / eVTOL / RC Strong fit Performance mobility packs Strong fit with validation Runtime-focused electronics Good, but may be more power than needed Maximum runtime per cell Consider higher-capacity energy cells Unmanaged consumer devices Not recommended Safety, Handling & Compatibility Notice This product is an unprotected lithium-ion cell. It should only be used by customers who understand lithium-ion cell safety and who are using the battery in compatible hardware, managed packs, or professionally designed assemblies. Improper use can lead to overheating, venting, fire, or explosion. Charge only with lithium-ion chargers or managed battery systems designed for the correct chemistry and cell count. Never short circuit, crush, puncture, incinerate, or expose the cell to water. Do not use cells with damaged wraps, dented cans, or missing top insulator rings. Do not mix with cells of different age, capacity, model, or state of charge in the same pack. For assembly, use spot welding rather than direct soldering to reduce heat damage risk. Store and transport in non-conductive cases; never carry loose cells in pockets or bags. Keep away from children and from applications for which the product is not specified. Not for e-cigarette, vape, or similar use. Common technical questions about the Molicel P45B. What is the capacity of the Molicel P45B? The P45B has a typical capacity of 4500mAh and a minimum capacity of 4300mAh. The data sheet lists typical energy as 16.2Wh and minimum energy as 15.5Wh. What is the discharge rating? The P45B is specified for 45A continuous discharge with an 80°C cut-off condition. Finished pack current should still be limited by thermal design, busbar/weld resistance, BMS ratings, fusing, and device requirements. Is this a protected battery? No. This is an unprotected flat-top 21700 cell and should be used only in equipment or packs with appropriate electrical and thermal protection. What charger should be used? Use a lithium-ion charger or battery-management system that uses a CC-CV profile to 4.20V per cell. The standard charge current listed by Molicel is 4.5A. Can the P45B fast charge? Yes. The data sheet lists 13.5A maximum charge current with a 70°C cut-off condition. Applications using high charge current should include temperature sensing, derating, and validation for cycle life and safety. What is the correct discharge cut-off voltage? The data sheet states a 2.50V discharge cut-off voltage per cell. Many pack designers choose a higher system cut-off to reduce stress and improve service life. Can the P45B be used in battery packs? Yes. It is a strong candidate for high-power custom battery packs when cell matching, spot welding, BMS sizing, fusing, insulation, and thermal validation are properly engineered. Can I solder wires directly to this cell? Direct soldering is not recommended. Spot welding is the preferred pack-assembly method because it reduces the risk of heat damage to the cell. What are the cell dimensions? Molicel lists the maximum cell envelope as 21.55mm diameter and 70.15mm height, with a maximum weight of 70g. Always confirm physical fit in the actual device or holder. What temperature range is allowed? The P45B data sheet lists 0°C to 60°C for charging and -40°C to 60°C for discharging. High-current use should include temperature monitoring and derating. Is the P45B better for power or runtime? It is a power cell with strong energy density. Choose it when the design needs high current and useful runtime in a 21700 format. If maximum runtime per cell is the only priority, compare it with higher-capacity energy-focused cells. What does 7mΩ AC impedance mean? It indicates very low cell impedance, which helps support higher current delivery and reduced voltage sag. Real pack resistance also includes welds, nickel, busbars, wiring, holders, fuses, and BMS components. How many cycles should I expect? The product listing uses a general 300+ cycle-life description, while the data sheet shows cycle-characteristics curves at 4.5A, 10A, and 100W discharge. Actual cycle life depends on temperature, charge current, discharge current, depth of discharge, and pack design. Can I carry this battery loose? No. Loose transport is unsafe because conductive objects can short the terminals. Always use a non-conductive battery case.
