Specifications of lithium ion cells

Nominal capacity- The nominal capacity (or rated capacity) of a Storage Component is the amount of energy that can be withdrawn from it at a particular constant current, starting from a fully charged state. The current used to rate batteries varies from one manufacturer to another, but it is typically either the 10-hour, 20-hour, or 100-hour rate. The 10-hour rate (C10) drains the Storage Component after 10 hours.

Maximum Capacity- The maximum capacity (or theoretical capacity) of a Storage Component is the total amount of energy it contains when fully charged. It is not possible to extract all this energy at any finite discharge current (it would take an infinite amount of time to extract it all), so Storage Component sizes are not typically given in terms of maximum capacity

DIMENSIONS CHANGE IN BATTERY

Primarily there are specified fixed values for the battery positive and negative terminal which can get affected by dust, crack, dislocation, deep scratch, or leakage which may adversely affect the commercial value of the cell can cause dimension errors.

During cycles, the battery thickness changes for the three reasons

(i) expansion and contraction of host materials due to lithium intercalation

(ii) electrode volume increase caused by irreversible reaction deposits

(iii) dead volume and pressure changes within the cell case depending on battery structure and construction.

CHANGE IN WEIGHT IN BATTERY 

Weight of the cell is usually affected by an overcharge of the battery, which causes a chemical reaction between the electrodes and the electrolyte, resulting in the release of heat and gases that expand inside the battery which can be physically seen as that causes a visible bump in the battery and sometimes there is manufacture defect which causes the battery to swell up.

Poor cell quality and design with low anode to cathode stoichiometric ratios, particulate contamination

Mechanical damage to electrodes induced either during cell assembly or from the product application

Excessive temperatures (Do not leave your cell phone inside your car)

Deep discharge of cells:  In a lithium-ion battery both the anode and cathode have ‘cubbyholes’ for the lithium-ion to shuttle back and forth.  When the battery is deep discharged, the protective passivation layer on the anode called the Solid Electrolyte Interphase (SEI) layer decomposes, with a new electrode and electrolyte surfaces coming in contact and new SEI layer is formed. All of these reactions lead to gas formation.

MECHANICAL TESTING AND STANDARDS

MECHANICAL TESTING:

1) DROP TEST: In this test, the battery is dropped from 3 different positions from a specific height, in 2 cases the battery is dropped from the terminals so both the terminals hit the ground first and sideway drop is done so the outer shell hits the ground first and observations are made accordingly for leakage and temperature rise.

2) VIBRATION TEST: The cells are vibrated for a specific amount of time in this case for 90 mins, vibrations are done at all 3 mutually perpendicular axes (x,y,z). Frequency range from 10-55 Hz and sweep of 1Hz change per min and observations are made for any leakage.

3) IMPACT TEST: Cells are impacted from the longitudinal axis parallel to the flat surface and perpendicular to the longitudinal axis and observations are made for an explosion or fire.

4) CRUSH TEST: Cells are crushed from their longitudinal axis parallel to the flat surface of the crushing apparatus.

5) Heating test: cells are charged as per the mentioned by the manufacturer, and heated in a circulating air oven at a rate of 5ºC per minute to 130ºC. At 130ºC, the oven is to remain for 10 minutes before the test is discontinued.

STANDARD TEST CONDITIONS:

STANDARD CHARGE: In this case, the cell is charged in a constant current specified in the datasheet, and then it is charged in a constant voltage while tapering the charge current. For testing purposes, the charging is done at a specific temperature range.

STANDARD DISCHARGE: In this case, the cell is discharged at a constant current and this is also done at a specific temperature range which is usually mentioned in the datasheet.

High Drain rate Charge/discharge condition: cells are charged at a constant current to a specified end current, and is discharged at a constant current. Cells are rested 10 mins after charge and 20 mins after discharge.  

DISPOSE PROCEDURE:

If they\'re alkaline batteries, you can throw them away or recycle them, unless your local government requires them to be disposed of at a designated facility. If they\'re rechargeable batteries or lithium-ion batteries, bring them to a recycling center so they can be properly disposed of.

1)The easiest way to dispose of batteries and electronics/electrical equipment is to return them to any store that sells them.

2)Consumers can also dispose of their used primary and rechargeable batteries, within the collection network which generally includes drop-off facilities at municipal depots, businesses, institutions, etc.

3)Call recycler who has been authorized by State Pollution Control Board
for processing & recycling of such used batteries.

4)Collect all used batteries in strong cardboard or wooden box. When
the box is full, close / seal it properly. Clearly label the box with “Used
batteries for disposal”.

5)Call recycler/disposal agency that has been authorized by State
Pollution Control Board for processing, recycling and/or disposal of such
used batteries.

Prepping single-use batteries for recycling:

• Place a piece of non-conductive clear tape over the ends to prevent any current transfer. You can also bag each battery individually instead of taping the ends.
• Store the batteries in a plastic or cardboard container that doesn’t conduct electricity in case there is a spark.

Prepping rechargeable batteries for recycling:

• Remove batteries from their electronics. Dead laptops must be recycled separately from dead laptop batteries. This is not required for small electronics like cellphones or iPods, which can be accepted by most battery recyclers.
• Cover the terminals with non-conductive tape clear tape.