Sealed cell
Cells sealed by means of a valve to maintain a predetermined pressure within the cell.

Sealing compound
Material, haven an asphaltic base. Is used to seal batteries manufactured in >> Ebonite respectively >> hard rubber containers.

Secondary battery
Rechargeable battery. >> Accumulator.

Secondary cell
>> Cell, secondary.

Sediment
>> Mud.

Self-discharging
Self-discharging is a temperature-dependent permanent chemical reaction process at a cell's or battery's electrodes, without connection to a consumer.

Separation
A separator is fitted between the positive and negative electrodes in order to isolate the latter from each other electrically.

Separator
A device used for the physical separation and electrical isolation of electrodes of opposing polarities. In certain cases, the separator can also be used for absorbing superfluous
electrolyte (microglass mat AGM). The separator for acid electrolytes generally consists of a porous PP/PE foil, while the separator for alkaline systems generally consists
of PP/PE mats. >> Leaf type separators, made from PVC, rubber or epoxy coated paper are still used for the production of SLI batteries in third world countries, from small battery
manufacturers or for special products, e.g. deep cycle batteries.

Series connection
Connection of the positive terminal of a cell/battery to the negative terminal of the next cell/battery. This increases the voltage of the battery network while keeping the capacity constant.

Service life
The length of satisfactory performance measured in years or charging /discharging cycles.

Service life, cyclical
The number of cycles a battery lasts before its capacity falls below the acceptable value.

Service life, useful
The useful service life of an accumulator expressed as the period of time prior to its capacity falling to a specified component of the rated value.

Shock-resistant
Battery protection against vibration achieved through design measures (e.g. fixing a plate block in position using hot-melt adhesive).

Short circuit, inner
The cells can also experience an inner short circuit in the case of fine short circuits (>> Tree formation). This will generally result in high self-discharging and will be reflected
in a sharp reduction in capacity.

Short circuit, outer
Low-impedance electrical contact between the battery poles. High temperatures can result in the battery being destroyed.

Short circuit tester
Machine for automatic testing of battery cells for short circuits, used in several areas of the >> battery assembly line.

Shrink holes
Casting defects, i.e. holes, hollows or depressions in the castings.

Sinter plate
An alkaline accumulator plate, whose support is formed from sintered metallic powder and which contains the active mass.

Sleeve
Used for industrial batteries, manufactured from industrial Polyethylene separator in endless tubes, cut into pieces and put over the positive plate.

Sleeving machine
Machine which automatically produces >> sleeves and put it over the plate. In state of the are machines a separator with a little bit more than the double width of the plate is used
and sealed alongside with a pair of >> crimping wheels. Very often combined with stacking machines to add the complementary plates for forming finished tractionary or stationary cells.

SLI battery
Abbreviation for Starting, Lightning and Ignition battery

Sludge
1. Waste from battery paste during pasting.
2. Exhausted positive mass during the aging process.
>> Sludging.

Sludging
Chemical process that takes place during discharging and charging onto the positive plates and results in the irreversible loss of positive mass.

Specific gravity
Weight per unit volume of a substance relative to that of water.

Spine casting machine
>> Die-casting machine

Sponge lead
Lead which is deposited electrochemically on the negative electrode; it has a sponge-like structure with high inner surface.

Stacker
>> Stacking machine.

Stacking
Procedure during cell mounting in which plates and separators are stacked alternately in a box before the connecting strap is cast. >> Connecting strap. >> Cast-on-Strap

Stacking robot
Robot used at the end of the >> battery assembly line or at the end of a >> finishing line for the automatic palletising of finished batteries.

Standard capacity
>> Capacity, nom.

Standard charging
Charging current that can be maintained indefinitely without the need for special cells or switchable battery chargers. Under normal circumstances, cells can be charged
overnight in 12 to 14 hours, in modern methods even down to 4-6 hours.

Starved cell
>> Cell, starved.

Stibine (antimony hydride SbH3)
Gaseous compound that forms on negative plates of lead-antimony cells, particularly when charging quickly or overcharging excessively.

Storage battery
A rechargeable battery. >> Secondary battery.

Sulphatation
The formation of lead sulphate at the electrodes of a lead accumulator by re-crystallization when the battery remains unused for a long time in deep discharge state.
A coarse grained lead sulphate is produced which can only be recharged with difficulty.

Sulphuric acid
Used in diluted form as an electrolyte in lead-acid batteries.

Switchback, temperature-dependent
Method for switching the charging current of a battery from highest-speed charging current to conservation charging current by means of a control circuit in the charger
which is triggered by the battery temperature.

Synthetic separator
Separator made of plastics and rubberlike materials.