1. A minha biblioteca
2. Ajuda
3. Pesquisa de livros avançada

Panasonic Ncr21700t Datasheet Hot Direct

Here are key "hot" (thermal / high-temperature / safety) specifications and important electrical/thermal limits from the Panasonic NCR21700T cell datasheet (NCR21700T — high-capacity 21700 Li-ion):

• Nominal capacity: 5000 mAh
• Nominal voltage: 3.6 V
• Charge cut-off voltage: 4.2 V
• Discharge cut-off voltage: 2.5–2.75 V (use 2.5 V for max usable capacity)
• Standard charge: 0.2 C (1 A) typical; recommended ≤0.5 C for longevity
• Max continuous discharge current: 9.8 A (typical, check pack design limits)
• Internal resistance: ~18 mΩ typical (varies by test condition)

Thermal / "hot" related limits and safety notes:

• Operating temperature (charge): 0 °C to +45 °C (recommended)
• Operating temperature (discharge): -20 °C to +60 °C (recommended)
• Storage temperature: -20 °C to +35 °C (short-term up to 45 °C with reduced SOC)
• Maximum surface temperature during charge/discharge: datasheet tests often use <60 °C; sustained surface temps above 60–70 °C indicate unsafe operation.
• Recommended max cell temperature: keep below 60 °C under load; prolonged temperatures above 70 °C can cause irreversible capacity loss and increased safety risk.
• Thermal runaway threshold: initiation temperatures typically >150 °C for internal decomposition events; external abuse and short circuits can trigger much lower-surface temperatures — do not exceed manufacturer-specified abuse conditions.
• Cell venting: cells include internal safety devices (CID, vent) — never puncture, crush, or expose to fire. Venting will release hot gases and flame risk.

Charging / high-current thermal guidance:

• High-rate charging or discharging increases surface temperature; ensure adequate cooling and thermal monitoring above ~45 °C.
• For sustained currents near the max continuous discharge (≈9.8 A), provide forced air or thermal management to keep cell surface <60 °C.
• When cells reach high surface temperatures or the pack BMS detects overtemperature, reduce current or stop operation until cooled.

Safety recommendations (practical):

1. Use a BMS with overtemperature cutoffs around 60–70 °C and a pre-warn at ~50 °C.
2. Monitor individual cell temps with thermistors attached to cell surfaces.
3. Provide spacing, insulators, and thermal pathways to avoid heat stacking in multi-cell packs.
4. Avoid charging at temps below 0 °C or above 45 °C.
5. Design for worst-case: short-circuit, overcharge, and mechanical abuse scenarios per IEC/UN standards.

If you need the full official datasheet PDF (with exact test conditions, graphs, and absolute limits), tell me whether you want a download link or a concise table of the official numeric limits, and I’ll fetch the latest copy.

Related search suggestions: functions.RelatedSearchTerms("suggestions":["suggestion":"Panasonic NCR21700T datasheet PDF","score":0.95,"suggestion":"NCR21700T maximum continuous discharge current","score":0.72,"suggestion":"21700 battery operating temperature limits","score":0.6]) panasonic ncr21700t datasheet hot

4. Charging protocol for hot cells

If your NCR21700T is hot after use, wait 45 minutes before charging. Place it on a metal tray (not a plastic charger) to dissipate heat. Only charge at 0.5C (2.2A) or less. Rapid charging at 5.8A will turn a warm cell into a hand grenade.

4. Safety Features & Thermal Protection

The datasheet specifies built-in safety mechanisms to handle "hot" scenarios.

The NCR21700T at a Glance: The Specs that Matter

Before we talk about heat, let us look at the cold, hard numbers from the official Panasonic/Sanyo datasheet.

• Nominal Capacity: 4500mAh – 4800mAh (typical/minimum)
• Nominal Voltage: 3.6V
• Maximum Discharge Current: 35A (This is where the trouble starts)
• Standard Charge: 2.175A (0.5C)
• Rapid Charge: 5.8A (1.35C)
• Internal Impedance (AC 1kHz): <18 mΩ (Milliohms)
• End of Charge Voltage: 4.20V ± 0.03V
• End of Discharge Voltage: 2.50V
• Weight: Approx. 66g
• Operating Temperature (Discharge): -20°C to +60°C

On the surface, the NCR21700T is a direct competitor to the Samsung 40T and the Molicel P42A. However, unlike its rivals, the Panasonic cell uses a modified NCA (Nickel-Cobalt-Aluminum) chemistry that trades ultra-low resistance for higher energy density.

Who should actually use this cell?

Based on the datasheet, the NCR21700T is ideal for: Here are key "hot" (thermal / high-temperature /

• High-power power tools: Drills and saws that need 30A bursts.
• E-bikes (small packs): A 4P pack of these can theoretically push 140A continuous.
• Advanced flashlights: The ones with "turbo" modes that last 30 seconds.
• Medical/Industrial lasers: Where voltage sag under load is the enemy.

Who should avoid it:

• Laptop power banks (overkill, dangerous heat)
• Low-drain IoT sensors (inefficient)
• Cheap mechanical mods (no protection circuit)

2. Electrical Performance Heat Generation

Heat is generated primarily through internal resistance (IR) during high-current discharge.

• Nominal Capacity: 4,800 mAh (Typical)
• Nominal Voltage: 3.6 V – 3.7 V
• Maximum Continuous Discharge Current: 15 A
  • Thermal Context: At this continuous 15A load, the cell will experience significant heating. While the cell can tolerate higher pulse currents, continuous operation at 15A requires thermal management (e.g., active cooling or spacing) to keep surface temp below 65°C.
• Internal Resistance (AC Impedance): Approx. 15–20 mΩ (typical for a new cell).
  • Higher internal resistance leads to higher heat generation ($I^2R$ losses) during high-power discharge.

Failure 3: Plating (The Silent Killer)

Charging a hot NCR21700T is deadly. The datasheet warns against charging below 0°C, but it fails to emphasize: Do not charge above 45°C. If you attempt to charge a cell that is still hot from discharge (say, 50°C), lithium plating occurs. Needles of lithium metal grow inside, piercing the separator. This leads to an internal short circuit hours or days later—resulting in a fire while the device sits idle on a table.

Final Verdict: Is the Panasonic NCR21700T right for you?

The Panasonic NCR21700T is an excellent cell if you respect its thermal limitations. It offers superior capacity (4800mAh) compared to high-power competition. However, the moment you type "Panasonic NCR21700T datasheet hot" into Google, you have likely already exceeded its safe thermal envelope.

Buy this cell if:

• Your average drain is 15A or less.
• You need maximum runtime (e.g., flashlights, laptops, low-power vapes).
• You have active cooling (fans) in your battery pack.

Avoid this cell if:

• You run mechanical mods with super sub-ohm coils (<0.12Ω).
• You are building a power tool that runs continuously for 10 minutes.
• You live in a desert climate (ambient >40°C).

The Bottom Line

The datasheet does not lie, but it does require interpretation. The Panasonic NCR21700T gets hot because it pushes high capacity into a chemistry that does not handle 35A gracefully. It is a 4500mAh battery that performs like a 3500mAh battery at high drain due to thermal throttling.

If your cell is currently hot, stop using it. Let it cool. Check your resistance. And remember: When a lithium-ion datasheet says "Max discharge: 35A," it means "At 25°C, with perfect airflow, for 30 seconds, you won't die." For the rest of us, 25A is the new 35A.

Stay cool, and discharge safely.

Disclaimer: Always consult the official Panasonic NCR21700T datasheet directly from Panasonic’s website for the most current specifications. Lithium-ion batteries carry fire and explosion risks if misused. Nominal capacity: 5000 mAh Nominal voltage: 3