A wide temperature lithium battery is a type of lithium battery specially designed in raw materials, electrolyte, and a separator to allow safe operation in the -40°C to 85 °C wide temperature range. It can support charging below 0°C by integrating smart charging IC to regulate the charging current according to different temperatures.

The wide temperature can be operated from  -40°C to 85 °C wide temperature range.

For normal temperature lithium batteries,  sub-zero charge is prohibited, which will cause the formation of lithium plating (lithium dendrites) on the surface of the anode as a result of safety risk or permanent damage to the battery.

 But a custom wide temperature battery allows charging below 0°C, due to the specially designed raw materials, electrolyte, and separator.

In cold environments, the electrolyte chemical and physical process of standard lithium batteries slows down and is unable to store energy, caused by an increase in their internal resistance and a reduction in the Ionic conductivity. Eventually, it presents a significant voltage drop and power failure.

Warning: Do not charge the standard lithium batteries in cold environments! 

The cold environment slows down the chemicals. The lithium ions move slowly to the graphite anode and start gathering on the anode surface as metallic lithium.

This process will generate dendrite formation. In a certain number of dendrites, it will pierce the separator and cause an internal short circuit. 

The wide temperature battery is specially engineered with advanced materials of low-viscosity electrolytes and anode modifications.

The low-viscosity electrolytes are filled with specific solvents (like methyl acetate) and additives that remain fluid and maintain high ionic conductivity even at -40°C.

To reduce the charge transfer resistance,the surface of the graphite anode is specially modified with soft carbon or carbon nanotubes, allowing the lithium ions to stay inside the anode during slow movement.

It uses specially designed low-viscosity electrolytes consisting of low-melting point solvents. In cold temperatures, the reduction of viscosity thickness improves the ionic conductivity. To prevent lithium plating formation, this electrolyte can help lithium ions shed their solvent shell more easily to enter the anode without gathering on the surface.

Yes. Wide temperature batteries are much safer than heating-board batteries. 

–The “Integrated Safety” of Wide-Temperature Batteries.

 The low-temperature performance is determined by cell quality. After abundant experimental tests, the specially-engineered materials and design, including advanced electrolytes and modified anode/ cathode material, truly prove the low-temperature resilience.

-The “Systemic Risks” of Heating Boards.

The external heating boards enable the battery to operate in a sub-zero environment. But it is failure-prone due to many factors.

• Physical Damage: Long-term thermal cycling and vibration will cause delamination or adhesive failure of the heating boards. This failure will result in poor thermal contact, reduced efficiency, and hot spot formation. The internal resistors or nickel foils on the boards are fragile to the external physical strength. During board application and battery installation, special care and strict thermal testing are required to avoid failure.

• Extra power consumption: The heating pads will continuously consume the battery energy and reduce its usable capacity.

• Non-uniform heating: For multi-cell battery packs, the major drawback is non-uniform heating and localized overheating. Due to the heating pad being improperly applied, the battery pack will suffer from cell inconsistency and ultimately compromise the safety, balance, and longevity.

 Poor maintainability in case of failure: In large battery packs, heating pads are often embedded between cells and integrated into the module structure. If a heating board fails, it is extremely difficult and labor-intensive to disassemble the pack to access and replace the faulty pads. More importantly, it is fundamentally unreasonable for an entire battery pack to be rendered inoperable due solely to the failure of a secondary component like a heating board.

There are three major technologies to improve the separator’s high-temperature resistance. But the Ceramic-Coated Separators are widely used in mass production due to cost-effectiveness and a mature process.

–Ceramic-Coated Separators: By coating nano-ceramic particles, Al₂O₃, SiO₂, ZrO₂, the polyethylene (PE) or polypropylene (PP) separator can not only improve mechanical strength to prevent internal short-circuits, but also enhance electrolyte wettability and retention to improve high temperature performance.

–Aramid-Coated Separators: Coating the poly-paraphenylene terephthalamide (aramid) fibers on the base membrane can offer exceptional thermal stability above 500°C, outstanding mechanical strength, and flame retardancy.

–Intrinsically High-Temperature Resistant Types: It contains three different types of Polyimide Separators, PBO Separators, Non-Woven / Glass Fiber Separators, replacing traditional polyolefins with inherently heat-resistant polymers.

PCB-controlled low-temperature charging is a type of hardware and software-coordinated battery management system to ensure safe charging in low temperatures. It uses temperature sensors attached to the battery body to monitor the battery temperature.If the measured temperature falls below 5°C, the microcontroller will activate the safe heating system(PTC, inverter, or internal) to warm the battery. When the battery reaches a safe temperature above 5°C, it starts to charge the battery normally. 

The PCB-controlled low-temperature charging can not only prevent lithium dendrite formation to improve safety, but also extend the battery lifespan. 

Extreme heat significantly accelerates the lithium-ion battery degradation, causing a sharply reduced cycle and calendar life. It will also critically elevate safety risks, including internal short circuits and thermal runaways.
The effects mainly occur in below factors.

• -Accelerated Parasitic Reactions: High temperature will not only accelerate the electrolyte and the SEI/anode reaction to cause SEI layer growth.
• -Material Breakdown: Under extreme heat, the electrolyte is decomposed, and the cathode crystal structure is degraded. Both points will cause permanent capacity loss.
• -Separator Shrink: Under 120-150°C high temperatures, polyolefin separators (PE/PP) begin to shrink or melt, causing an internal short circuit.

Warning: Storing a battery at 100% SOC in a hot environment is the worst case to degrade the battery at the fastest speed.

Based on the same conditions of 0.5C charge and 1C discharge, the cycle life varies with different temperature ranges.

• Under room temperature, the wide temperature lithium-ion battery can reach 1000+ times cycle life.
• Under high temperature 85°C, the battery lifespan will be shortened by around 500 times cycle life based on 0.5C charge and 1C discharge.

-Under low temperature -20°C, the battery lifespan can only be reached around 300 times cycle life based .

Yes.VTCBATT wide temperature batteries can continuously operate at 85°C. You can refer to the test curve below for the 85°C cycling.

High temperatures accelerate the battery’s internal chemical reaction even during storage. The electrolyte will react with the anode to thicken the SEI layer.SEI’s continuous growth will fade its capacity.
Under a high-temperature environment, the normal electrolyte reduces its ion transport capability. The electrode of cathode and anode materials gets corroded by the acidic environment, generating a weak capability to store lithium ions. 

The internal electron leakage, also named self-discharge, has increased greatly in hot environments. You can recharge the battery to recover a portion of its capacity, but mostly this is irreversible damage to the battery’s internal materials.

Yes. Wide temperature batteries are suitable for military and defense systems.

Because those systems are deployed in harsh environments that experience extreme temperatures, both hot and cold. Only wide-temperature batteries can operate stably and safely in extreme environments. 

Yes. Wide temperature batteries can be used in IoT and GPS trackers.

Some IOT and GPS trackers are installed remotely in extreme environments for agriculture, climate, mining, and oil field production. The wide temperature battery can operate reliably and stably under these scenarios.

Wide temperature lithium batteries are best for oil, gas, and mining environments.

The wide temperature lithium batteries are divided into non-rechargeable and rechargeable types.

 -Non-rechargeable battery type. The lithium thionyl chloride battery is the best for oil, gas, and mining environments. It has an ultra-wide temperature range from  -55°C to +85°C, and an ultra-long 10-year shelf life in a compact size.

 -Rechargeable battery type. Both the wide-temperature LiFePO4 battery and the wide-temperature lithium-ion battery can be best suited for oil, gas, and mining environments.

Even with the same operation temperature range from -40°C to +85°C, they have their own advantages and disadvantages. The wide-temperature lifepo4 battery has a longer cycle life, but lower energy density with less capacity. The wide-temperature lithium-ion battery has shorter cycle life, but higher energy density with more capacity.  

               Wide-temperature LiFePO4 battery vs. Wide-temperature lithium-ion battery

Yes. Wide temperature batteries are suitable for arctic applications. But you must use a proper sub-zero charging system to ensure a safe and reliable charge in arctic conditions. Otherwise, there are great safety risks of internal short circuits and thermal runaways.

Yes. Wide temperature lithium batteries can be customized for specific projects.
Most industrial and military projects have customized requirements for different temperature performance and structure design. Customization can be designed from the cell level to the system level, combining multiple factors of low-temperature charge and discharge, high-temperature cycle life, mechanical ruggedness, and form factors.