In the cold winter, the battery level of mobile phones drops "cliff-like", and in the hot summer, the charging speed of electric vehicles slows down inexplicably - temperature is the culprit behind the scenes. Lithium batteries are as sensitive to temperature as human skin. In severe cold and heat, they may "strike" or "self-destruct". This article will dismantle how temperature destroys batteries at the molecular level and provide scientific response strategies.
I. The "frozen seal" of low temperature on batteries
1. How does low temperature "paralyze" batteries?
- Electrolyte viscosity soars: Below 0°C, the fluidity of the electrolyte drops sharply, the migration of lithium ions is like being stuck in a quagmire, and the internal resistance increases sharply.
- Capacity "shrinks": At -20°C, the capacity of lithium batteries is only about 30% (data source: Argonne National Laboratory, USA).
- Voltage dive: iPhone may automatically shut down at -5°C, which is actually a protection mechanism triggered by low voltage.
2. Fatal risks of low-temperature charging
- Lithium dendrite growth: When charging at low temperatures, lithium ions easily form dendrites on the surface of the negative electrode, piercing the diaphragm and causing a short circuit.
- Case: In 2018, a Norwegian Tesla owner used supercharging at -30°C, and the battery pack was permanently damaged.
3. Who is more vulnerable in low temperatures?
- Lithium iron phosphate (LFP): -10°C capacity retention rate ≈50%, inferior to ternary lithium (NCM) ≈70%.
- Lead-acid battery: -20°C capacity ≈40%, and the electrolyte may freeze and expand to damage the shell.
II. High temperature "chronic murder" of batteries
1. How does high temperature "cook" batteries?
- Electrolyte decomposition: When >40°C, the electrolyte begins to vaporize, and the internal pressure increases, causing bulging.
- Uncontrolled growth of SEI film: High temperature accelerates the thickening of SEI film on the surface of the negative electrode, permanently locking active lithium ions.
- Permanent capacity decay: After 3 months of storage at 45°C, the capacity loss of lithium batteries is ≈20% (Battery University data).
2. Instant fatal injury of high temperature: thermal runaway
- Chain reaction: local short circuit → temperature surge → electrolyte combustion → explosion.
- Typical case: In 2021, the battery pack of NIO caught fire due to continuous fast charging in summer.
3. "Differential attack" under high temperature
- Ternary lithium (NCM/NCA): Nickel accelerates oxygen evolution at ＞60°C and has poor thermal stability.
- Solid-state battery: significant high temperature resistance advantage (can withstand 150°C in the test).
III. Extreme temperature response guide
1. Low temperature survival rules
- Preheat before use:
Electric vehicle: remotely turn on battery preheating through the APP before departure (such as Tesla's "depart on time" function).
Mobile phone: store close to the body or use a heated mobile phone case (such as OtterBox ThermSeries).
- Slow charging: charge with a low current of ≤0.2C at low temperatures (such as a 5V1A adapter).
- Refuse "freezing charging": charge the battery after it returns to a temperature above 0°C.
2. High temperature protection strategy
- Physical heat dissipation:
Mobile phone: remove the protective case to avoid playing games while fast charging.
Electric vehicle: delay charging after parking (wait for the battery to cool down), or choose a liquid cooling system (such as Xiaopeng G9).
- Avoid exposure to the sun:
The temperature of the car's center console can reach 80°C in summer, so do not place power banks or electronic devices.
- Charging temperature limit:
Most devices automatically suspend charging when the temperature is greater than 45°C (such as the high temperature warning prompt of iPad).
3. Temperature management for long-term storage
- Ideal environment: 15°C-25°C, humidity <50%.
- Do not store at full charge: disconnect the power after charging to 50%-60%, and recharge regularly (once every 3 months).
IV. The "black technology game" between temperature and battery
1. Self-heating battery
Principle: The battery is integrated with an electric heating film, which heats up in extreme cold (such as the all-weather battery of CATL that can be used at -30°C).
2. Phase change material (PCM)
Application: Tesla battery packs are filled with paraffin-based PCM, which absorbs heat and melts at high temperatures, and solidifies and releases heat at low temperatures.
3. Heat pump temperature control system
Advantages: 50% energy saving compared to traditional PTC heating (such as the heat pump system of BYD Dolphin).
V. "Sequelae" of temperature damage
1. Irreversible damage
- "Sequelae" of low temperature: lithium dendrites may cause micro-short circuits after lurking for several months.
- "Branding" of high temperature: excessive growth of SEI film leads to permanent capacity decay.
2. "Temperature trap" of warranty terms
- Most manufacturers do not provide warranty for battery damage at extreme temperatures (such as Apple's specified operating temperature of 0°C-35°C).
Conclusion: Reconcile with temperature and extend battery life
Batteries are not "immortal", but scientific management can delay aging. Remember three key words: avoid extremes, keep warm, and maintain frequently. When you hold your warm phone tightly in the cold winter, or enjoy the cool cabin of an electric car in the hot summer, don't forget that the battery behind you is experiencing a temperature battle.
Action Guide:
- Download battery health monitoring apps (such as AccuBattery) and check the loss regularly.
- Enable device temperature protection in extreme weather (such as iPhone low power mode).
- Choose a temperature-resistant model when replacing the battery (such as liquid-cooled battery packs for electric vehicles).
