Why does your lithium battery perform poorly in winter? In-depth analysis of the impact of cold weather on lithium battery performance.

When winter arrives, many people find that their phone batteries drain twice as fast as usual, the range of their electric vehicles drops drastically when the heater is on, and outdoor energy storage devices become less efficient. This isn't because your devices are broken; rather, a clear electrochemical principle governs all of this.

Interestingly, many users' first reaction is "the battery is old"-but that's not necessarily true. The vast majority of capacity loss at low temperatures is temporary and reversible . Once you understand the principle, the solution is actually not complicated.

This article will systematically break down the core mechanisms by which cold weather affects the performance of lithium batteries, provide quantitative data and horizontal comparisons of different chemical systems, and offer practical suggestions for users and designers.

1. The impact of cold weather on lithium batteries: What happened?

First, describe the phenomenon, then explain the reasons.

In low-temperature environments, the most typical effects of lithium-ion batteries are: reduced usable capacity, significantly increased internal resistance, and lower charging and discharging efficiency . Specifically, from a user's perspective, this manifests as: the battery percentage dropping rapidly (from 50% to 20%), devices suddenly shutting down but showing power when plugged in, and insufficient voltage during high-power usage.

Compared to lead-acid batteries, lithium-ion batteries do have a relative advantage at low temperatures-lead-acid batteries experience more severe performance degradation in extreme cold, often accompanied by permanent lifespan loss. However, "relatively better" does not mean "no problems," and the challenges that lithium batteries themselves face at low temperatures cannot be ignored.

The core changes can be summarized in three points:

During discharge, the actual usable energy decreases.

During charging, the battery's efficiency in accepting electrical energy decreases.

When using high current, the voltage drops more quickly, making it easier for the equipment to trigger protection shutdown.

The good news is that most of these changes are reversible. Once the temperature rises, the capacity usually recovers significantly- provided you didn't force-charge it at low temperatures .

2. Why does lithium battery capacity decrease in winter? Scientific explanation.

The effects of low temperature permeate the entire electrochemical reaction chain of lithium-ion batteries. Let's break it down layer by layer:

① Lithium ions "can't move anymore" - electrolyte viscosity increases

Inside a lithium battery, lithium ions need to shuttle back and forth in a liquid electrolyte to transport energy from the positive electrode to the negative electrode (charging) or vice versa (discharging). At lower temperatures, the electrolyte becomes thicker, significantly reducing the diffusion rate of lithium ions. You can think of it like swimming in syrup instead of water – the efficiency is naturally much lower.

The slower the ions reach the electrode surface, the more the entire electrochemical reaction is "stuck".

② The electrode material "doesn't want to move"-reaction kinetics deteriorate.

At low temperatures, the kinetics of lithium-ion insertion and extraction in cathode materials (such as NMC ternary lithium or LFP lithium iron phosphate) and anode materials (usually graphite) slow down significantly. Simply put, electrode materials are "sluggish" at low temperatures, reducing the number of lithium ions that can participate in effective chemical reactions, thus releasing less energy.

③ Internal resistance "soars" - triple resistance superimposed

Low temperatures simultaneously increase three types of resistance:

The electrolyte conductivity decreases (its conductivity deteriorates).

Increased interfacial charge transfer resistance (making it more difficult for lithium ions to "climb" onto the electrode surface)

The impedance of the SEI film (solid electrolyte interface film) increases (the ion-conducting ability of the negative electrode protective layer decreases at low temperatures).

The combined effect of these three resistances leads to a significant increase in the battery's internal resistance. Higher internal resistance results in a lower effective voltage during discharge, causing energy loss to be dissipated as heat, further reducing the actual usable energy.

④ The most dangerous situation – lithium deposition caused by low-temperature charging

This is the most alarming aspect. During low-temperature charging, lithium ions cannot be inserted into the graphite anode in time, and will precipitate on the anode surface in the form of metallic lithium , forming a lithium coating, which can develop into lithium dendrites in severe cases .

The dangers of lithium dendrites are: irreversible capacity loss; further increase in internal resistance; in the most severe cases, dendrites can pierce the separator, causing short circuits or even thermal runaway.

Therefore, charging below 0°C is absolutely forbidden, without exception.

3. How much capacity do lithium batteries lose in winter?

The magnitude of capacity loss depends on temperature, discharge current, battery chemistry, and the battery's aging condition. The following data is based on NREL test reports and AAA's winter range study for electric vehicles:

For electric vehicles, AAA's 2023 winter test report shows that in an environment of -7°C, the average driving range (without heating) decreases by about 12% , while with heating on, the decrease rises to about 41% . This indicates that while battery capacity loss is partly due to the battery itself, additional loads such as heating, defrosting, and cabin heating are the main reasons for the significant reduction in driving range in winter .

Two important reminders:

The battery percentage displayed by the device is often inflated at low temperatures , and the actual usable energy is lower than the displayed value. This is because the BMS (Battery Management System) cannot accurately reflect the low-temperature state after being calibrated at room temperature.

Capacity loss caused by low-temperature discharge can usually be recovered after the temperature rises; however, damage caused by lithium deposition due to low-temperature charging is permanent .

4. Which type of lithium battery performs better in cold weather?

This issue is actually quite controversial within the industry, and there's no simple "which is definitely better." There are too many variables that affect low-temperature performance, and chemical names are only one aspect.

NMC ternary lithium vs LFP lithium iron phosphate

The common view in the industry regarding the comparison of the two at low temperatures is:

NMC (ternary lithium) : At moderate low temperatures (around -10°C), it has relatively good energy density and capacity retention, which is one of the reasons why most consumer electronics and early electric vehicles chose NMC.

LFP (lithium iron phosphate) : It has better cycle life and safety at room temperature, but the capacity decay of standard formulations may be more significant at extremely low temperatures (below -20°C). However, in recent years, manufacturers such as BYD and CATL have made a lot of formulation optimizations for the low-temperature performance of LFP, and the gap is narrowing.

It is worth noting that, within the same chemical system, the differences in formulations between different manufacturers can be far greater than the differences between different chemical systems . When purchasing, prioritize looking at the manufacturer's published low-temperature discharge curve (discharge capacity retention rate at -20°C) and minimum charging temperature limit, which is more valuable than simply looking at "NMC or LFP".

Low-temperature optimized formulation: the real differentiator

Some battery manufacturers that focus on low-temperature applications will adopt:

Low-viscosity organic solvent electrolytes (such as formulations containing ether solvents).

Special SEI film-forming additives improve low-temperature interface properties

Thinner electrode coating shortens the lithium-ion diffusion path.

These formulation improvements are particularly effective in extremely cold conditions (below -30°C), but often come at the cost of sacrificing some room-temperature energy density.

Battery packs with built-in heating: the most immediate effect.

Regardless of the chemical composition, battery packs with integrated preheating and good thermal insulation structures perform far better than bare cells in frigid environments. This is currently the most decisive factor in the difference in winter performance between electric vehicles and outdoor energy storage devices, which will be discussed in detail in the design section later.

5. How to improve the performance of lithium batteries in winter?

The following recommendations are listed in order of importance to battery health. The first two are bottom-line principles, and the latter are for optimizing performance:

 First rule: Never charge below 0°C

This is not a suggestion, but a principle. Low-temperature charging is a direct cause of lithium deposition, and the resulting damage is irreversible. If your device runs out of power in a low-temperature outdoor environment, bring it back to room temperature for at least 30 minutes before connecting it to charge .

Second point: Preheat before use, retain warmth after use

Devices that support preheating (most modern electric vehicles have this feature): Preheating the battery indoors or via an app before setting off allows it to reach a higher temperature before use, which can significantly improve discharge capacity and charging acceptance.

For devices without a preheating function (mobile phones, flashlights, drones, etc.): warm them up in an inner pocket or insulated bag before use; the effect will be immediately visible.

 Article 3: Controlling high-current discharge in extremely cold environments

High-current discharge (such as rapid acceleration of electric vehicles or takeoff of drones) at low temperatures causes a more severe voltage drop due to internal resistance, resulting in not only low efficiency but also the potential to trigger over-discharge protection. Driving gently in winter will improve battery performance.

Article 4: Proper Storage

Batteries that have not been used for an extended period (more than 2 weeks):

Storage temperature: 10°C–25°C , dry and protected from light.

Remaining charge: Keep it between 30% and 60% (to avoid damaging the positive terminal by leaving it partially charged, and to avoid damaging the negative terminal by leaving it undercharged).

Check the battery status every 1–2 months and replenish it to the above range.

Article 5: Tips for managing electric vehicle energy consumption in winter

The core dilemma of driving in winter is that the heater consumes too much electricity, but it's too cold without it. Here are a few compromises:

Prioritize using heated seats and steering wheel ; these localized heating systems only require a few hundred watts, which is much more efficient than the air conditioning's heating.

Preheat the carriage when plugged in (heated by an external power source, without consuming batteries).

When parking, try to choose sheltered or indoor parking lots to reduce battery heat loss.

6. How we design lithium battery packs for cold-weather applications

The following content is based on our team's practical design experience in cryogenic energy storage and electric special vehicle battery pack projects, and is applicable to professional scenarios that require stable operation at -20°C to -40°C.

Thermal Management System (TMS): The Core of Cryogenic Design

For battery packs designed for extremely cold operating conditions, thermal management is not an "optional" feature, but a "standard feature." Our typical solutions include:

PTC self-regulating heating film : power density approximately 150–300 W/m², advantages include self-regulating characteristics for safety and reliability, and moderate cost; suitable for preheating requirements from -20°C to 0°C.

Liquid cooling + liquid heating integrated system : The same liquid circuit is used for heating in winter and cooling in summer. The system has a high degree of integration, but the cost and weight are also greater; suitable for automotive-grade projects with strict performance requirements across the entire temperature range.

Thermal insulation materials and cold bridge control : The outer shell is made of low thermal conductivity materials or an insulation layer is added (such as aerogel felt, with a thermal conductivity as low as 0.015 W/(m·K)). In the structural design, metal parts are avoided to run directly through the inside and outside to prevent cold bridge effects that cause localized low temperatures.

BMS Low Temperature Protection Strategy: Hard Logic First

A battery management system (BMS) must perform the following for low temperatures:

Low-temperature charging prohibited : When the cell temperature is below 5°C, charging commands are completely prohibited (configurable threshold depends on cell specifications).

Low-temperature current-limited discharge : When the temperature is between -10°C and 5°C, the maximum discharge current is limited to 30%–50% of the rated value to avoid frequent triggering of the voltage drop protection due to excessive internal resistance.

Real-time temperature monitoring : Each package is equipped with at least multiple temperature sensors to ensure uniform temperature sampling and prevent localized overcooling from being masked by the average value.

Cell selection and verification

Early in the project, we require cell suppliers to provide capacity retention curves for 0.2C discharge at -20°C , as well as a test report on charge acceptance capability at -10°C . Suppliers who can provide complete low-temperature test data are generally more reliable in terms of formulation and manufacturing consistency.

For extreme scenarios below -30°C (such as polar research equipment and high-altitude drones), the standard lithium-ion system is no longer sufficient. We will evaluate emerging technology routes such as lithium metal batteries or solid-state batteries, but these solutions are still in the mass production breakthrough stage.

System-level collaboration: Batteries are not isolated islands

Battery pack thermal management must be designed in conjunction with the overall system/vehicle system. A common mistake is that the battery thermal management is designed well, but the battery is immediately subjected to full load after the system is turned on. The battery is "brushed" by a large current before it has fully warmed up, rendering the thermal management ineffective.

Our experience is that setting up "cold start power ramp-up" logic at the system firmware level-automatically limiting the initial power output based on the cell temperature after power-on, and gradually releasing full power as the temperature rises-is almost imperceptible to the user, but has a very significant effect on protecting battery life.

7. Frequently Asked Questions (FAQ)

Q1: Can lithium batteries be discharged and used below zero degrees Celsius?

Yes, but performance will decrease. Discharging itself doesn't cause lithium deposition, it only reduces usable capacity and weakens power output. However, charging is absolutely not allowed -even at -1°C, there is a risk of lithium deposition. The principle for judgment is simple: discharging is acceptable, charging should wait for the temperature to recover.

Q2: Why does my electric car's range drop so much in winter?

Battery capacity reduction is only part of the reason, typically contributing 10%–20% to the range loss. The bigger culprit is the heating system – according to AAA tests, turning on the heater can result in a total range loss of over 40%. Other factors include increased rolling resistance due to lower tire pressure at low temperatures and decreased motor efficiency at low temperatures. It is recommended to prioritize seat heating instead of the vehicle's central heating system, as the energy savings are significant.

Q3: What is the optimal temperature and charge level for storing lithium batteries in winter?

Recommended temperature: 10°C–25°C , in a dry, dark environment. Recommended charge: 30%–60% . Do not store at full charge (this puts stress on the positive terminal), nor store at a low charge (this may cause over-discharge damage). Check and recharge to the above range every 1–2 months.

Q4: Is the damage caused by using batteries at low temperatures permanent?

It depends on the situation. Capacity loss due to simple low-temperature discharge is mostly temporary and recovers as the temperature rises. Lithium deposition caused by low-temperature charging is permanent damage , and as the deposition accumulates, the battery deteriorates, posing a safety hazard. Therefore, the answer to this question depends on whether you have ever charged your battery at low temperatures.

Q5: My phone suddenly shuts down in low temperatures. Is the battery faulty?

It's most likely not broken. At low temperatures, the battery voltage may drop to the phone's BMS (Battery Management System) protection threshold earlier, even though there may still be some charge remaining. Once back in a warmer environment, the phone will usually power on automatically and display the remaining battery level. This is a normal electrochemical phenomenon, not a malfunction. However, if this happens frequently even at room temperature, then battery aging should be considered.

Q6: Are there any lithium batteries recommended for use in extremely cold outdoor environments?

the minimum operating temperature and low-temperature discharge retention rate in the product specifications , rather than simply looking at the brand or chemical name. Currently, some battery packs on the market are optimized for low-temperature scenarios and will specify capacity retention rate data at -20°C or -30°C (such as reaching more than 80% of the rated capacity) in the specifications. These products provide a more reliable basis for selection.

Summary

Cold weather causes lithium batteries to "deteriorate," a result of the combined effects of three physicochemical mechanisms: thickening of the electrolyte, slowing of electrode kinetics, and increased internal resistance. In most cases, this deterioration is temporary and reversible-as long as you don't charge them at low temperatures.

For ordinary users, the two most important things are: do not charge below 0°C and preheat the battery pack as much as possible before use . For professional applications that require stable operation in extremely cold environments, the design quality of the thermal management system and BMS low-temperature protection strategy is the real watershed that determines the performance of the battery pack.

With the maturation of low-temperature optimized electrolyte technology and the gradual implementation of solid-state batteries, there is still significant room for improvement in the performance of lithium batteries in extremely cold environments. However, until then, understanding the principles and using them correctly remains the most economical and effective solution.