News

Sonnenschein Lithium GmbH
Sonnenschein Lithium was founded in 1984, with plant facilities at Büdingen near Frankfurt, Germany. The creation of the company was preceded by transfer of knowledge from prestigious partner firms and several years of market experience as their distributor. Today, the company is the leading manufacturer in the European market for lithium thionyl chloride batteries.

Research and Development has been a decisive factor in establishing the company's leadership position. Environment-friendly manufacturing processes, continuous improvement and constant enhancement of the battery system as well as the specialization in lithium batteries help to strengthen the competitive edge of Sonnenschein Lithium's customers in their respective markets
and ensure the availability of reliable power supplies for their electronic products, today and in the future.

Sonnenschein Lithium was one of the first battery manufacturers to obtain ISO 9001 certification of the quality management system in 1993.

Close co-operation with our customers during the design phase is part of the company's basic phi-losophy. Sonnenschein Lithium offers comprehensive support from experienced specialists, and is committed to securing its position as a market leader and a competent, reliable technology partner.

The Lithium/Thionyt Chtoride Battery
The Sonnenschein Lithium/thionyl chloride inorganic electrolyte battery is a power source that is suited to the requirements of the new generation in microelectronics. For example, CMOS memories as well as utility meters require a lightweight power source to provide a safe and reliable performance over a wide range of environmental conditions, for long periods of time.

The Sonnenschein Lithium battery is a component that can be permanently connected to a circuit and, in many cases, will last the entire lifetime of the equipment.

Battery Characteristics
The major advantages of the Sonnenschein Lithium battery are:

High cell voltage.
The battery has a nominal voltage of 3.6 Volts, which is considerably higher than any other commercially available primary cell.

Wide temperature range.
The batteries are capable of operating in a wide temperature range normally from -55°C to +85°C. One series, however, has an extended temperature range of up to 130°C.

High Energy Density.
The electrochemical system offers the highest energy densitiy of any available primary battery: up to 650 Wh/kg and 1280 Wh/dm3.

Superior shelf life and reliability.
The Sonnenschein Lithium battery has an outstandingly long shelf life. Tests have shown that storage for ten years at room temperature results in a capacity loss of less than 1% per year.

Sonnenschein Lithium batteries are also extremely reliable and failure rates in memory back-up applications were found to be below 200 FIT (FIT: Failures in Time. 1 FIT = 1 failure in 109 component hours)

Safe design.
The battery's design has a major influence on its safety characteristics.

In the bobbin version, the cathode is cylindrical in shape. The anode is swaged against the inner wall of the battery case. This offers several advantages in terms of safety. In the event of an unintentional short-circuit, the discharge currents do not become very strong. The heat generated, primarily at the contact surface between the anode and cathode, can easily be channelled to the outside. This design leads to a safe battery that needs no additional rupture vent.

In the flat battery versions, the anode is pressed onto the bottom of the case, and the cathode is disk-shaped. Flat batteries are wider than they are high. They are just as safe as the Bobbin type batteries.

Hermetically seated case.
The hermetically sealed case is essential for the long shelf life and inherent safety of the devices in which the batteries are used. The cover is welded to the can. A glass-to-metal seal is used to insulate the positive terminal.

The PulsesPlus™ battery
Some applications require high current pulses of up to several Amperes in addition to low background current. Bobbin-type lithium batteries have high capacity and energy density, but low current capability due to their low rate design. To overcome this, PulsesPlus™ was developed, a hybrid battery that combines a bobbin-type cell with a patented high rate, low impedance HLC (hybrid layer capacitor). This hybrid system delivers extremely high currents with an excellent safety margin.

The Hybrid Layer Capacitor is charged by the battery. It has low output impedance and thus can
readily deliver the pulses. It is recharged by the battery in advance of the next pulse, thus eliminating passivation effects.

High pulse applications involve low-background currents, and brief periods of high-current pulses over an extended period of time. These applications include automotive emergency roadside assistance systems, traffic telematics, GPS tracking devices, GSM modems, oceanographic devices, RFID transponders, automatic meter reading, security devices, emergency equipment, wire-
less sensors, defibrillators and other medical devices.

Figure 1	Cross sectional view of a ½ AA size cell (bobbin-design)

Safety

The chemical reaction
The battery consists of a lithium (Li) anode, a carbon (C) cathode, and a non-aqueous electrolyte (a solution of lithium
tetra-chloroaluminate in thionyl chloride). This solution performs a dual task: as the electrolyte for ion transport, and as an active depolarizer. The Teflon™-bonded carbon cathode serves as a catalyst for cathodic reduction. The generally accepted reaction mechanisms are as follows:

Anodic reaction:
4 Li 4 Li+ + 4 e-
Cathodic reaction:
2 SOC52 + 4 e-
SO2 + S + 4 C5-
Overa55 reaction:
4 Li + 2 SOC52
S + 4 LiC5 + SO2

Most of the sulphur dioxide generated during discharge dissolves in the electrolyte, preventing pressure bui5d-up within the battery.

Long-term behaviour
The long shelf life of the Sonnenschein Lithium batteries is a result of the fact that a thin protective 5ayer of LiC5 forms on the anode as soon as the lithium first comes into contact with the electrolyte. This 5ayer prevents further reaction or loss of capacity on stand. The problem of anode corrosion, as occurs in aqueous systems, is thus eliminated. On the other hand, the protective layer on the anode may cause a delay in the voltage build-up if relatively high loads are applied, or after extended storage at elevated temperatures. This voltage delay is not experienced at all in microampere applications, such as in typical CMOS circuits.

Standards
Genera5 safety recommendations for lithium batteries have been published in the standards UL 1642 and IEC 60086-4.

UL-Recognition
Sonnenschein Lithium Batteries are recognized by UL under file MH 12827. The following text or a modified version thereof appears on each battery:

WARNING: Fire, explosion, and severe burn hazard. Do not recharge, disassemble, heat above 100°C, incinerate, or expose contents to water.

Protection against charging

Whenever lithium batteries are not the single power source in a circuit the following measures are recommended by the Underwriters Laboratories:

Figure 2 Comparison of different battery systems. The curves represent typical best values of commercial cylindrical cells when discharged at 25 °C at the 1000 hour rate. The area under the curves corresponds to the energy density listed below. The list also gives a note of the sealing method 1 Li/SOC52 1280 Wh/dm3 hermetically welded 2 Li/SO2 430 Wh/dm3 hermetically welded 3 Li/CFx 550 Wh/dm3 crimped elastomer seal 4 Li/MnO2 580 Wh/dm3 crimped elastomer seal or hermetically welded 5 Li/FeS2 450 Wh/dm3 crimped elastomer seal 6 A5ka5ine 280 Wh/dm3 crimped elastomer seal

Protection against charging
Whenever lithium batteries are not the single power source in a circuit the following measures are recommended by the Underwriters Laboratories:

The battery should not be connected in series with an electrical power source that would increase the forward current through the battery.

The circuit shall include one of the following:

A. Two suitable diodes in series with the battery to prevent any reverse (charging) current. The second diode provides protection if the other one fails.

B. A blocking diode or the equivalent to prevent any reverse (charging) current and a resistor to limit current in case of a diode failure. The resistor should be sized to limit the reverse (charging) current to the maximums IR, max shown below.
In addition to this UL requirement, which gives the safety limits, Sonnenschein Lithium recommend to limit the reverse (charging) current to values below 10 µA. This will ensure that service life is not affected.

Figure 3	Safety wiring for memory back-up representing case B of UL recommendsations.

Protection against forced discharge
Forced discharge of a cell can occur when it is connected in series with other cells and when it is not protected with a by-pass diode. In these cases the maximum continuous discharge currents have to be reduced to the following values:

Glossary

Features and attributes of the various series

SL-300 series
Keywords: standard use and sand-by

• Excellent shelf life (10 years)
• Extremely low selfdischarge (1 % or less per year)
• Suited for long-term use with low current
• For operation at low current levels with long stands
• Intermittent discharge with medium current level provided the average is not below the active current level
• Temperature range from -55 °C to +85 °C (flat cells up to +75 °C)
  

Bobbin-type or flat cells

SL-500 series
Keyword: extended temperature range

• Extension of temperature range up to +130 °C
• Somewhat smaller capacity
• Otherwise like the SL-300 series
  

SL-700 series
Keyword: enhanced start

• Major improvement of voltage delay at the start of discharge at medium
  current levels (TMV)
• Intermittent discharge at medium current levels
• Best results if used after no more than 3 years of storage
• Otherwise like the SL-300 series

Computer batteries

• Supplied with plastic outer case, cable and connector
• Classified by UL as "user-replaceable"
• Some versions with current and/or voltage limitation
• Some versions contain two or more cells
• Otherwise like the SL-300 series

Customer Benefits

Sonnenschein Lithium has focused its ongoing efforts on promoting the understanding and further development of lithium batteries. This determination offers to the customer a number of decisive benefits such as:

• Access to over twenty-five years of experience in research and development,
  production and marketing
• Adaptability and reliability in meeting rapidly evolving customer needs
• Detailed technical support in terms of design and application - before, during and after the purchase
• Highly qualified experts available for support on short notice
• Customized production of single and multi-cell batteries to meet specific requirements
• Reliable delivery, secured by contractual agreements and second sourcing.
  

For successful use of a battery, the co-operation between the customer and the supplier must commence at the earliest possible point: at times it is simply more economical to design a circuit for the characteristics of the best suitable energy supply, rather than having to forgo its advantages because it is too late for changes.

Active current level
Discharge current of approx. 2 µA/cm2 of anode surface. If a battery is operated at a constant current level that is higher than the active current, then its pulse current capability remains intact over its entire life.

Anode surface area
The anode surface area provides an indication of the current capability and design of a battery.

Available capacity
The diagrams showing available capacity give an indication of the confidence
range of expected capacities at different current levels depending on ambient temperature.

Current drain ranges
This term stands for the actual load of the battery. The load is correlated with the duration of discharge to be expected on continuous current and an operating voltage above 3 Volts.

Low current drain:
Duration of discharge greater than 2000 hours

Medium current drain:
Duration of discharge between 20 and 2000 hours

High current drain:
Duration of discharge less than 20 hours

End voltage
The discharge curves shown in this catalogue assume that discharge continues until the voltage drops to 2 Volts. In most applications, this does not yield any major differences from the capacity achievable with higher end voltages (e.g. 3 Volts), since it is not usual for discharge to occur continuously at high or medium current levels.

Internal resistance
Internal resistance is defined as voltage drop divided by current. The value changes during the discharge. From the start, it drops to a steady state value. Before the end voltage is reached, internal resistance rises due to the chemical and physical processes in the cell.

Internal resistance also depends on temperature, storage, and current levels involved.

Maximum continuous discharge current
Current yielding approximately 30 % to 60% of the nominal capacity.

Nominal capacity
The average capacity of a battery type under favorable conditions (load, ambient temperature). In the diagrams showing "Available Capacity", the nominal capacity is marked with a dot.

Nominal current
Current level at which the nominal capacity can be obtained.

Nominal voltage
The nominal voltage characterizes the electrochemical system (in this case, Li/SOCl2). It results during discharge at low current drain levels.

Operating voltage
The average voltage during discharge at a given load and temperature.

Orientation effect
A reduction of available capacity observed on cells of size C and larger when discharged upside down at low and ambient temperature.

Pulse current capability
Current level yielding approximately 30 % to 60% nominal capacity when a 1s pulse is applied once a minute.

TMV, transient minimum voltage
The minimum voltage experienced during the voltage delay when a battery is first connected to a load.

Transport Regulations

Lithium Batteries are dangerous goods, UN 3090. Therefore they are generally subject to transport regulations depending on the transport mode. The table on this page gives a brief summary. However, Sonnenschein Lithium Batteries in this catalogue having not more capacity than 3 AA cells are exempted from dangerous goods regulations because they meet the provisions listed
hereafter:

• Cells contain no more than 1 g of lithium.
• Batteries contain no more than 2 g of lithium.
• They have passed the tests required by the UN manual of tests and criteria. Therefore special
  provision 188 applies and they are not subject to the regulations, provided the following general rules are observed:
• Batteries are separated from each other in the packaging so as to prevent shorting.
• Batteries are packed in strong outside packaging (except when installed in electronic devices) with a
  gross weight not exceeding 30 kg per package.
• Each package is capable of withstanding a 1.2 m drop test in any orientation without damage
  to cells or batteries contained therein, without shifting of the contents so as to allow battery to
  battery (or cell to cell) contact and without release of contents; and
• The package and the shipping documents are marked with a notice indicating that it contains
  lithium batteries and shall - if damaged - be quarantined, inspected and repacked.

A Technical notice with more detailed information is available upon request.

Table Transport regulations for Sonnenschein Lithium Batteries with more than 2g lithium content. It is necessary to refer to the listed regulations and instructions for detailed information. They are reviewed on a regular basis. The table is based on the 2003 revisions. The applicable documents are: ADR: European Agreement concerning the International Carriage of Dangerous Goods by Road, IATA DGR: International Air Transport Association, Dangerous Goods Regulations ICAO: International Civil Aviation Organization, Technical Instructions for the Safe Transport of Dangerous Goods by Air. IMDG Code: International Maritime Dangerous Goods Code RID: International Statutory Order on the Conveyance of Dangerous Goods by Rail UN: United Nations Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria Class 9 label, reduced size, black and white Handling Label for Cargo Aircraft Only, reduced size, black and orange