We have the capability to design custom high temperature batteries in a range of shapes, sizes, and capacities to suit the specific needs of you and your equipment.

For continuous 85°C operation, the best battery for high temperature use is a cylindrical Li-ion cell — 18650 or 21700 format — with high-temperature electrolyte formulation. These outperform LFP (lithium iron phosphate) and polymer pouch cells in sustained heat environments. But cell chemistry is only half the answer. BMS configuration and thermal management determine whether performance holds after 500 cycles. A correctly engineered high temperature lithium battery pack retains 80% capacity after 500+ cycles at 85°C.

UN38.3 is mandatory for all international Li-ion shipments — a legal requirement under IATA (air freight) and IMDG (sea freight) regulations. EU market access additionally requires alignment with EU Battery Regulation 2023/1542 and CE marking where required by product category. US applications typically need UL listing or UN38.3 compliance, depending on application type. CMB maintains UN38.3 documentation for all standard configurations, available to qualified buyers on request.

If your operating temperature is higher than 85°C, our Chief Technology Officer will evaluate your specific needs and design a custom battery pack to meet your equipment’s operating requirements.

Temperature is the single largest driver of lithium battery high temperature degradation — more than charge cycles alone.

At 25°C (standard): 500–800 cycles to 80% capacity retention
At 60°C continuous: roughly 200–300 cycles
At 85°C, without high-temp design: as few as 50–100 cycles

CMB’s lithium ion battery high temperature packs sustain 500+ cycles at 85°C — matching standard-temperature performance at a 60°C higher operating point — through combined cell selection, electrolyte formulation, and BMS thermal limiting. A li-ion battery at high temperature doesn’t have to degrade fast. It has to be engineered not to.

For battery samples, if we have the desired battery or a compatible battery in stock, the delivery time is generally 4-7 days. If we don’t have the desired battery in stock, we require 2-3 weeks for production. Mass production generally takes 30 days (without stock). If there are enough batteries in stock, it will take about 1-2 weeks to fulfill an order.

This is the most underestimated failure mode in outdoor IoT deployments. A sealed enclosure in direct sunlight at 38°C ambient reaches 55–70°C internally within 30–60 minutes — because electronics generate heat with nowhere to go. A battery rated at 60°C is already at its ceiling before factoring in humidity, which independently accelerates electrolyte degradation.

The rule engineers miss: always specify battery operating temperature for the enclosure’s internal temperature — not the ambient air outside it. That gap is typically 15–25°C under real field conditions. A device “safe” at 38°C ambient may be running its battery at 63°C or more.

Technically possible — but a standard BMS rated −20°C to 60°C will trigger over-temperature shutdown before your application reaches operating conditions at 70–85°C. The cell isn’t the failure point. The BMS is.

A true 85°C pack needs three BMS requirements met simultaneously:
1. Adjusted cutoff thresholds (standard 60°C ceiling → configured 88–90°C)
2. Current tapering at elevated temperatures to protect cell longevity
3. Multi-point NTC temperature sensing across the pack

Without all three, even the best high temperature Li-ion battery will either shut down prematurely or degrade rapidly. This is why a cell swap alone won’t solve a high-temperature application problem.