IEEE 1725-2011 pdf download
IEEE 1725-2011 pdf download.IEEE Standard for Rechargeable Batteries for Cellular Telephones.
5.2.2 Electrode design criteria
Electrode design constituents for both the anode and the cathode shall be designed to assure performance, safety, and durability in the designated application. Design criteria shall specify material content, purity, and environmental factors that will enable the electrode material to support the manufacturing process and usage designated application.
5.2.3 Electrode capacity balance and electrode geometry
The charge capacity of the negative electrode shall he greater than the positive electrode. The reversible capacity of the negative electrode shall be greater by at least 0.1 % plus process tolerance.
The active area of the negative electrode shall completely cover the active areas of the positive electrode. The negative electrode shall be at least 0.1 mm wider (plus process margin) than the positive electrode on top and bottom of the cell unless process capability/stability is demonstrated to he less than 0.1 mm.
5.2.4 Electrode tabs (connection to cell terminals)
The manufacturer/supplier shall establish optimal exposed tab length and tab overhang. A single tab shall not overhang both sides of the electrodes. Figure 5(a) and Figure 5(b) illustrate this principal.
5.2.5 Tab insulation
This subclause includes requirements for tab insulation.
5.2.5.1 Application of insulation
The tab that has the opposite polarity as the enclosure shall be insulated where it exits the electrode assembly. Insulation shall continue until it reaches the point of attachment to the cell terminal. One embodiment of this principal is illustrated in Figure 5(c). Insulation may be accomplished through one or more insulating schemes. If a tab is located where there is only a one-layer separator to isolate the opposite electrode, additional insulation shall be used, which may be additional layers of separator material or tape.
5.2.5.2 Insulation characteristics
Insulation material shall have electrochemical, chemical, mechanical and thermal stability, and shall have good adhesion and puncture strength, over the temperature range, —40 °C to 150 °C.
5.2.6 Cell vent mechanism
Cells shall be designed to include a consistent vent design or mechanism, for example, foil, edge, seam, or score.
5.2.6.1 Retention of cell contents
The vent mechanism shall be designed to minimize projectiles and maximize retention of cell contents.
When subjected to this test, no part of an exploding cell shall penetrate the wire screen such that some or all of the cell protrudes through the screen.
5.2.7 Overcurrent protection device
The manufacturerisupplier may employ an oveicurrent protector [such as a positive temperature coefficient resistor (PTC) resistor or other protective measure] integrated or built into each cell to protect from hazards in the event of external short circuit andlor overcharge. If the cells are qualified per this standard using a PTC resistor or other protective measure, it shall be included in the cells used in the battery pack design and manufacture.
5.2.8 Maximum recommended voltage
The cell manufacturer shall provide a recommended maximum voltage for the appropriate pack overvoltage protection function.
5.3 General manufacturing considerations
5.3.1 Materials specifications
Materials specifications shall be developed to identify and limit impurities to levels below critical limits.
5.3.2 Impurity avoidance
All undesirable impurities in materials should be identified, specified, reduced to acceptable levels, and controlled throughout the manufacturing process.
5.3.3 Cleanliness of manufacturing operations
In the manufacturing environment, management of temperature, humidity, and impurity levels shall be specified, controlled, and monitored. Also, environmental management of materials, before and after the manufacturing process, shall be specified and monitored. The introduction of metal contamination from equipment or process shall be prevented.
5.3.4 Manufacturing traceability
The cell manufacturing process shall have a cell traceability plan. This plan should include methods by which traceability can be implemented at any date during product lifetime and after production to determine lot designation and performance data related to the cell. Use manufacturer’s/supplier’s specifications or documentation to ensure control of this criteria or process.
5.3.5 Uniform coating of active materials
Coating weight, thickness, and uniformity of electrodes for the positive electrode and negative electrode shall be controlled within the tolerance set by cell specification. Use manufacturer’s/supplier’s specifications or documentation to ensure control of this criteria or process.
