Battery Packs

Battery packs are constructed from a range of cells whose hook up, capacity and performance are selected for the application.

All cells, whatever the chemistry, secondary or primary have working voltage ranges and temperature operating constraints aside from discharge and charge (secondary only) rates.

The terminology for a multi cell battery pack is “n”S”n”P cells connected in series and in parallel. For example a 4S2P has 4 series connected by 2 parallel, making 8 cells.

The energy, in Watt Hours, attributable to a battery pack is the [capacity *nominal sum of connected series voltage]. So for a lithium ion pack 4S2P constructed with 2.6AH cells whose nominal average cell voltage is 3.6V then the energy is (3.6*4)(2.6*2) watt hours(WH) =75WH.  The allowable rate for discharge and charge is a function of the specific chemistry and construction make up.

Packs are provided as “soft” or “hard”. Soft packs are where  the cells are encased in shrink wrapping, suitable for an enclosed assembly only. These soft packs, will as a minimum, include a safety protector circuit. Hard packs are generally custom form factor in flame retardant ABS. The TBS smart battery pack  is supplied in a hard case and is a standard product available up to 97WH (3S3P), 88WH(4S2P or 2S4P) 100mm*75mm*50mm external dimension.

All battery packs will incorporate a Battery Management System (BMS) which in its simplest form will be a safety protector but more usually incorporates an energy manager such as in your lap top battery. Capacity display can be push button or direct via digital interface to the host equipment, like lap top

BMS discussion

TBSPP-Li-PowerPak Series

BMS data sheet

TBS provides it’s own series of standard battery packs to enable small volume applications and for quick turn applications. These are fully featured packs providing primary and secondary protection, coulomb SMBUS Fuel Gauge, press on demand state of charge (SOC) via a five segment LED display.

Comparison of the major rechargeable chemistries:

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