Electrical Energy Storage Technology

Cell Assembly

Continuous improvement of existing battery concepts (e.g. lithium-ion batteries) and the development of novel technologies (e.g. lithium-air or zinc-air) require a testing setup for assessing single battery components (e.g. electrodes, separators, electrolyte, etc.) or complete cells. Special testing and measuring cells, also referred to as analytical cells, and coin cells are used to enable testing setups which simulate real operation conditions including different test scenarios (e.g. cyclization, electrochemical impedance spectroscopy (EIS), cyclic voltammetry, etc.).

The assembly of coin and analytical cells must to be performed in a special environment (e.g. glovebox) to protect single components against air, water and nitrogen. In addition, specialized tools (e.g. coin cell press) are needed. Subsequent cyclization and analysis are performed using special hardware (e.g. Neware, Ivium, Zahner).

The obtained results enable predictions for scaling the components to larger battery formats as well as a better understanding of the electrochemical processes that occur. Furthermore, different battery models can be parameterized (e.g. in COMSOL), optimizing the utilization of batteries and battery systems


Technische Universität Berlin
Electrical Energy Storage Technology
Institute of Energy and Automation Technology
Faculty IV
Office code EMH 2
Einsteinufer 11
D-10587 Berlin

Coin cells

Coin cells are compact batteries that are often used where space is limited or power consumption is low. According to IEC 62281, coin cells are defined as "small round cells whose overall height is smaller than their diameter." Typical fields of application are car keys, wristwatches and calculators. Due to their simple structure, the small amount of material used, and the possibility of manual production, coin cells allow a cost-effective investigation of innovative or optimized battery materials in the field of research and development. Designations for coin cells (for example CR2032) generally contain information about the cell chemistry used (C: lithium manganese dioxide), the diameter (20: ⌀20mm) and the total height (32: 3.2mm). Type 2032 coin cells, which are the most common coin cell format for experimental investigations, are composed of electrodes, the electrolyte, a separator and a spring as well as at least one spacer. Depending on the materials used and the quality characteristics examined, the construction sequence of the cell components may vary.


Building EMH
Room EMH 255

Test cells

Test cells are available in both coin cell and pouch cell formats. One possibility to examine cell materials in the coin cell format is the ECC-Ref test cell from EL-CELL. Unlike the coin cell, the casing is not pressed but rather screwed together. This allows multiple use. Additionally, special spacers within the cell and a separator carrier, which forces alignment of the electrodes, ensure a higher reproducibility compared to coin cells. These separator carriers may also be equipped with reference electrodes to enable three-electrode measurements. In lithium-ion batteries, lithium reference electrodes can be used to separately measure the anode and cathode potentials and thus better identify decharge processes. This anode potential can be used to detect the potential drop to 0V vs. lithium to determine the critical point of metallic lithium deposition causing lithium plating. The three-electrode measurements can also be used to perform separate EIS measurements for anodes and cathodes.