Your device sits inside a water meter on a street corner. It transmits a reading every hour, endures -55 °C winters and +85 °C summers, and cannot be touched for a decade. You get one battery choice — get it wrong and the whole installation needs a costly service visit.
This is exactly the problem lithium thionyl chloride (Li-SOCl₂) batteries were engineered to solve. Once engineers understand why, most never specify another chemistry for long-life, low-drain industrial power. This guide explains what a Li-SOCl2 battery is, how it works, where it wins, and how to choose and ship it — so you can source with confidence.
A lithium thionyl chloride (Li-SOCl₂) battery is a primary (single-use, non-rechargeable) lithium cell that pairs a lithium metal anode with thionyl chloride (SOCl₂), which acts as both the cathode material and the liquid electrolyte. It delivers a nominal voltage of 3.6 V — among the highest of any commercial primary battery — with a flat discharge plateau of roughly 3.0–3.6 V across most of its capacity.
Because it is hermetically sealed, low-maintenance and built for very long standby life, it is the default power source for equipment that must run unattended for a decade or more: smart meters, remote sensors, asset trackers and other field devices where replacing a battery is difficult or expensive.
At discharge, lithium metal is oxidised at the anode while thionyl chloride is reduced at the cathode, producing lithium chloride (LiCl), sulfur and sulfur dioxide. The high cell potential comes from this vigorous reaction, so a single cell can power a 3.6 V circuit without series stacking.
A key behaviour is passivation. When the cell is idle, a thin lithium chloride film forms on the lithium anode. This film protects the anode from internal corrosion and is exactly what gives Li-SOCl₂ its famously low self-discharge. The same film explains a brief voltage delay when a cell is first placed under load after long storage — a design consideration for high-pulse applications covered in Section 5.
Li-SOCl₂ delivers roughly 500–730 Wh/kg by weight and up to about 1,300–1,420 Wh/L by volume — around three times that of alkaline cells and clearly above lithium manganese dioxide. A smaller, lighter cell can power a device far longer.
What this means for your business: smaller cells deliver the same service life, which shrinks housing size, shipping weight and per-unit bill of materials. For OEMs producing at volume, the savings compound quickly.
The nominal 3.6 V output stays almost constant across discharge, dropping only near end of life. Many competing chemistries show a gradual voltage taper.
What this means for your business: voltage-sensitive electronics behave predictably from first use to last — fewer field complaints, fewer low-voltage firmware edge cases, lower aftersales support cost.
Self-discharge is typically below 1% per year (some grades reach about 0.7%). A cell manufactured today retains usable capacity well into the next decade.
What this means for your business: you can hold inventory and pre-assembled devices in a warehouse for months without degradation, simplifying supply-chain planning and reducing warranty exposure.
Standard bobbin cells operate from -55 °C to +85 °C, and high-temperature grades reach +125 °C to +150 °C — ideal for outdoor infrastructure, down-hole sensors and harsh industrial heat.
What this means for your business: one battery SKU covers deployments across climates and geographies — qualify one cell, ship globally without regional variants.
The stainless-steel case and glass-to-metal hermetic seal mean Li-SOCl₂ cells do not leak under normal operating conditions.
What this means for your business: battery leakage is a leading cause of field failures and warranty claims in battery-powered hardware. Hermetic sealing removes that failure mode and protects your brand in the field.
A 10–15 year service life is not just a specification — it is a commercial argument. Every battery replacement means a field visit: labour, scheduling, travel and device downtime.
What this means for your business: specifying Li-SOCl₂ converts a recurring operational expense into a one-time capital cost — the most significant TCO advantage the chemistry offers for large metering or IoT fleets.
The table below compares Li-SOCl₂ with the two most common alternatives in long-life primary applications. Figures are typical manufacturer values and should be confirmed against the specific datasheet.
| Chemistry | Voltage | Energy density (Wh/kg) | Operating temp. | Self-discharge / yr | Typical life |
| Li-SOCl₂ | 3.6 V | 500–700 | -55 to +85 °C (HT to 150 °C) | <1% | 10–20 years |
| Li-MnO₂ | 3.0 V | 280–300 | -20 to +60 °C | 1–2% | 5–10 years |
| Alkaline | 1.5 V | 80–150 | 0 to +50 °C | 2–3% | 2–5 years |
Bottom line: where a decade-plus, maintenance-free life and low self-discharge matter more than cost per cell, Li-SOCl₂ is usually the right chemistry.
Li-SOCl₂ cells come in two primary constructions. Choose based on your discharge profile.
| Bobbin-type (ER) | Spiral-wound (ERM) | |
| Construction | Cylindrical carbon cathode, lithium anode lining | Tightly wound anode/cathode strips |
| Continuous current | Low (typically ≤100 mA) | High (up to ~2 A) |
| Pulse current | Moderate | Excellent |
| Energy density | Higher | Slightly lower |
| Typical use | Smart meters, wireless sensors, asset trackers | Alarms, beacons, GPS, cellular IoT bursts |
Bobbin cells dominate metering and IoT because of their high energy density and low self-discharge. Spiral cells suit applications that demand occasional high-current pulses — for example, a cellular module that wakes, connects, transmits and sleeps. Where a device combines a very low average drain with high pulses, a hybrid design pairs a bobbin cell with a supercapacitor that absorbs the pulse load.
- Smart metering: electricity, water and gas meters that must run 10–15 years with low-maintenance wireless communication (LoRaWAN, NB-IoT, Sigfox). This is the single largest application globally.
- Industrial IoT and wireless sensing: remote pressure, temperature, humidity and vibration sensors, predictive-maintenance systems and pipeline telemetry where battery replacement is costly.
- Asset tracking and GPS telematics: long standby life keeps trackers powered between infrequent location reports.
- Medical and safety-critical devices: for example, automatic external defibrillators (AEDs) that must remain ready for years.
- Industrial and security systems: memory backup and alarm circuits that need reliable power during outages.
- Define the load profile: a low continuous drain suits a bobbin cell; a device that transmits in high pulses needs a spiral cell sized for that surge.
- Fix capacity and size: decide the required capacity, physical size (AA, C or custom packs) and terminal type.
- Map the temperature envelope: confirm the minimum and maximum temperatures the cell will face in deployment.
- State the required life and storage: how long the device must run and how long it may sit in inventory before commissioning.
- Demand compliance documents: ask for the UN38.3 test report, MSDS/SDS and transport certificates before committing.
- Validate with the manufacturer: work with a supplier that will confirm cell selection against your real load profile rather than selling a one-size-all cell.
Because Li-SOCl₂ cells contain lithium metal, they are regulated as dangerous goods for transport. The UN Manual of Tests and Criteria prescribes eight UN38.3 tests — altitude simulation, thermal cycling, vibration, mechanical shock, external short circuit, impact, overcharge and forced discharge. Every cell offered for transport must pass these tests, and the manufacturer should provide the test report.
IEC 60086-4:2025 (6th edition) tightened definitions for leakage and venting and revised over-discharge test criteria for cells such as the ER14505, so they remain stable even when accidentally drained in series.
For classification and labelling, Li-SOCl₂ batteries are shipped under UN3090 (lithium metal batteries) or UN3091 (lithium metal batteries contained in or packed with equipment) and are assigned to Class 9 miscellaneous dangerous goods. For air freight, the IATA Dangerous Goods Regulations (2025, 66th edition) apply Packing Instruction 968 to lithium metal batteries, which are shipped as Cargo Aircraft Only (CAO) and are forbidden on passenger aircraft.
Handling best practice: store cells in a cool, dry place (ideally below 30 °C), protect terminals from short circuit during transport, avoid crushing or piercing the casing, and never attempt to recharge a primary cell.
Your supplier should provide the MSDS/SDS, UN38.3 report and transport certificates so your forwarder and customs broker can clear the shipment without delay.
Teerbo (Dongguan, China) engineers and supplies primary lithium batteries — including Li-SOCl₂, NiMH and soft-pack lithium — for OEM and industrial customers worldwide. We support you from selection through prototyping, and provide compliance documentation including UN38.3 test reports and MSDS/SDS with your shipment.
Share your load profile and operating conditions with our team and we will recommend the right cell for your product. Request a quote for your project.
No. Lithium thionyl chloride is a primary chemistry and is not designed for recharging. Its role is long-life, maintenance-free single-use power.
Typical field life is 10–20 years in low-drain applications, and some premium grades are rated longer. Actual life depends on the load profile and temperature.
Standard cells operate down to -55 °C, with low-temperature variants available for even colder deployments.
Use Li-SOCl₂ for the longest life, lowest self-discharge and widest temperature range. Choose Li-MnO₂ when you need higher pulse current and simpler handling of moderate drains.
Evaluate production experience, quality control, technical support, customisation and capacity, and demand traceable documents — UN38.3 test reports, MSDS/SDS and relevant certifications — before ordering.
You will normally need the UN38.3 test report, MSDS/SDS and transport certificates. Your supplier should provide these; they are essential for air freight under IATA Packing Instruction 968.
Standard bobbin cells are low-rate. For high pulse loads, choose a spiral-wound cell or a hybrid bobbin-plus-supercapacitor design so the cell is not overloaded.
Lithium thionyl chloride batteries remain the benchmark for long-life primary power in smart metering, industrial IoT and field instrumentation. Their 3.6 V output, ultra-high energy density, wide temperature range and minimal self-discharge make them the engineering choice wherever replacement is impractical. Sourcing from a manufacturer that backs the cell with verified UN38.3, MSDS and IATA documentation keeps your supply chain simple.
Thinking of using Li-SOCl₂ in your next product? Contact Teerbo today with your load profile and we will help you select, qualify and ship the right battery.
