The intention of this glossary is to explain certain technical terms and their use in this brochure. The definitions are not necessarily identical to terms that are standardized in a different context.

Active Current Level
Discharge current of approximately 2 µA/cm2 of anode surface. This current level is sufficient to prevent passivation of a battery under most circumstances.

Active Material
The material in the electrodes of a battery which takes part in the electrochemical reactions of charge or discharge.

Anode
The electrode in an electrochemical cell where oxidation takes place. In primary batteries it is always the negative electrode. In lithium batteries, the active material of the anode is lithium.

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

Available Capacity
The total capacity that will be obtained from a battery at defined discharge rates and other specified operating conditions. In the Sonnenschein Lithium Product Data Catalogue, the diagrams showing available capacity give an indication of the confidence range of expected capacities at different current levels depending on ambient temperature.

Battery
An electrochemical power source comprising one or more cells. Cells can be electrically connected in a series and/or parallel assembly. Battery Pack

Battery Pack
An assembly of electrochemical cells electrically interconnected in an appropriate series/parallel
arrangement to provide the required operating voltage and current level. A battery pack most often
includes an additional jacket and wires/connectors. In this documentation, the term "battery" is used instead of battery pack unless exclusion of a single cell without the cable and connector is intended.

Bobbin
A cylindrical electrode (usually the positive) pressed from a mixture of the active material, a conductive material, such as carbon black, the electrolyte and/or binder with a centrally located conductive rod or other means for a current collector.

Capacity
The total quantity of electricity in ampere-hours (Ah) that can be withdrawn from a fully charged battery under specified conditions of discharge. Available capacity, Nominal capacity.

Capacity Retention
The fraction of the full capacity available from a battery under specified conditions of discharge after it has been stored for a period of time.

Cathode
The electrode in an electrochemical cell where reduction takes place. In primary batteries it is always the positive electrode.

Catholyte
Coined word that is used for the active cathodic material of liquid cathode systems indicating that it is contained in the electrolyte.

Cell
The basic electrochemical unit used to generate or store electrical energy. In this documentation, the term "cell" is used only to emphasize this basic unit. Otherwise the term "battery" is used.

Closed-Circuit Voltage (CCV)
The voltage of a battery during discharge.

Cut-off Voltage
Minimum voltage level when a battery is considered no longer usable in a given application.

Current

Drain

Current Collector
An inert part of high electrical conductivity used to conduct current from or to an electrode during discharge.

Current Density
The current per unit electrode surface area.

Depassivation
A procedure that prepares a battery for operation when otherwise initial passivation would cause a
voltage drop below the cut-off voltage.

Depth of Discharge (DOD)
The ratio of the capacity delivered by a battery at time t during discharge to its total capacity available under specified conditions.

Diffusion
The movement of species under the influence of a concentration gradient.

Discharge
The conversion of the chemical energy of a battery into electrical energy and withdrawal of the electrical energy into a load.

Discharge Efficiency (Yield)
Percentage of the nominal capacity delivered during a given duty.

Discharge Rate
The rate, usually expressed in amperes, at which electrical current is taken from the battery.

DOD

Depth of discharge

Drain
Discharge current from a battery. Expressed in amperes (A). With respect to Sonnenschein Lithium
Batteries, the following regimes are distinguished:

High Current Drain
Duration of discharge less than 20 hours

Medium Current Drain
Duration of discharge between 20 and 2000 hours

Low Current Drain
Duration of discharge greater than 2000 hours

Duty Cycle
With respect to periodic current pulses, the term is used to denote the ratio between on- and off time.

Efficiency

Discharge efficiency

Electrode
A part of the cell where electrochemical processes take place. Anode or cathode.

Electrolyte
The medium which provides the ion transport mechanism between the positive and negative electrodes of a cell.

End Voltage

Cut-off voltage

Energy
The energy of a battery is obtained from the product of capacity and operating voltage. It is measured in Watt-hours (Wh).

Energy Density
The ratio of the energy available from a battery to its volume (Wh/dm3).

Energy, specific
The ratio of the energy available from a battery to its weight (Wh/kg).

Flat Construction
A cell design in which the electrodes are arranged in layers.

Forced Discharge
Discharging a cell or battery, with an external battery or other power source, below zero Volts into voltage reversal.

Internal Resistance
Internal resistance is defined as voltage drop divided by current change: Ri = U / I. The value changes during discharge.
See figure 2-13.

Jelly Roll

Spirally wound construction

Liquid Cathode
Thionyl chloride is an example for a liquid cathode. Catholyte

Maximum Continuous Discharge Current
The highest current at which a battery will still provide more than 15 % of its nominal capacity. This
value is given to help decide on possible applications.

Maximum Pulse Current
It is an indication of the pulse current capability. The values given in the Sonnenschein Lithium Product Data Catalogue refer to 6 pulses of 0.5 s each per hour at 25 °C at a current level of approximately 10 mA/cm2.

Midpoint Voltage
The voltage of a battery midway in the discharge between the fully charged state and the end voltage.

Nominal Capacity
The average capacity of a battery type under favourable conditions (load, ambient temperature). In the diagrams of the Sonnenschein Lithium Product Data Catalogue showing "Available Capacity", the nominal capacity is marked with a dot to give an idea of the actual capacity values that can be expected under practical conditions.

Nominal Voltage
The nominal voltage characterizes the electrochemical system. It is observed during discharge at low current drain levels.

Open Circuit Voltage (OCV)
The voltage between the terminals of a cell or voltage when the circuit is open (off-load condition).

Operating Voltage
The average voltage during discharge at a given load and temperature over the entire duration of discharge until the end voltage is reached.

Overdischarge

Forced discharge

Parallel Assembly
A battery assembly where all cell terminals of equal polarity are connected together. Capacity and current capability are multiplied. Voltage is invariant. series assembly

Passivation
The phenomenon by which a metal, although in conditions of thermodynamic instability, is protected due to the formation of a surface layer.

Primary Battery
Non-rechargeable battery. secondary battery

Positive Temperature Coefficient Resistor (PTC)
Equivalent to a resettable fuse connected in series with a battery pack. It undergoes a large and abrupt increase in resistance at a predetermined current and temperature.

Safety Vent
A normally sealed mechanism which allows for the controlled escape of gases from within a cell.
Secondary Battery Rechargeable battery. primary battery

Self-Discharge
Loss of useful energy at rest or during discharge because of internal chemical reactions.

Separator
An ionically-permeable but electronically non-conductive material installed between the cell anode
and cathode. It prevents any electronic contact between them.

Series Assembly
A battery assembly in which the positive terminal of one cell is connected to the negative terminal of the next cell and so forth. Voltage is multiplied, capacity and current capability are invariant.

parallel assembly

Service Life
The period of useful life of a primary battery before a predetermined end voltage is reached.

Shelf Life
The duration of storage under specified conditions at the end of which a battery still retains the ability to deliver a specified performance.

Short-Circuit Current (SCC)
The initial value of the current obtained from a battery in a circuit of negligible resistance. In a broader sense it is the current evolving during short-circuit of a battery.

Specific Energy

Energy, specific

Spirally Wound Construction
Refers to the arrangement of electrodes in a cylindrical cell. It is made by winding the electrodes and separator like a jelly-roll. As opposed to bobbin construction.

Stand-by Battery
A battery designed to sustain certain functions of a circuit in the event of a main power failure.

Storage Life

Shelf Life

Transient Minimum Voltage (TMV)
The minimum voltage experienced during the voltage delay when a battery is first connected to a load.

Vent

Safety vent

Voltage Delay
Time delay for a battery to recover to the required output voltage after being connected to a load.