Battery cell expansion measurement

• Long-term observation of expansion during charging and discharging cycles
• Measurement of forces that occur, with monitoring of temperatures
• Optimization of pressure distribution and service life

Description

Due to the charging and discharging cycles, the age and the resulting temperature fluctuations, disturbing gases are produced in the battery cell, which expands as a result. This places a high load on the housing and cell surroundings. Stresses vary depending on the design and on the formulation of the chemical compounds.

Specific requirements

• Precise measurement of the forces – i.e. expansion with temperature – during cell charging and discharging
• Accurate assessment of long-term behavior and the aging process

A critical look at the details is necessary for exact reproducible recording. Precisely defined pretensioning forces can be applied by the fine pitch of the mounting screws. Uniformly applied tightening torques, if possible, generate an even distribution of forces (preload).

The gases produced during use and the resulting expansion of the flexible pouch cell generate a force on the receptacle surface. The resulting force depends on the chemistry, cell structure, shape, temperature and number of charging and discharging cycles.

Solution

A precise investigation of the temperature/force curve during various charging and discharging cycles provides key insights into the relationship between the chemical constituents and structural variants. This question is becoming more urgent with ever-increasing packing densities, which are usually achieved by cascading many cells.

With the precise investigation of the expansion, the composition of the battery and the design of the housing can be optimally adapted. This knowledge of the maximum thermal and mechanical load under extreme conditions thus helps to define a precisely specified requirement for the environment in order to guarantee protection and safety time.

Video Application