Battery Testing

Battery Testing ResearchGamry provides several systems for battery testing and has included a number of unique features in our software that help to reduce acquisition and analysis time.

Gamry’s potentiostats are well suited for battery testing of materials to coin cells and all the way to large format cells.  We even have a system for stack testing.  All of our potentisotats are electrically isolated from earth-ground (aka floating) so they are ideal for testing of grounded cells or working in conjunction with large DC power supplies. 

Gamry Advantages

Gamry’s potentiostats are well suited for battery testing of materials to coin cells and all the way to large format cells.  We even have a system for stack testing.  Additionally, all of our potentisotats are electrically isolated from earth-ground (aka floating) so they are ideal for testing of grounded cells or working in conjunction with large DC power supplies.  

Our software has been optimized for battery testing needs.  We have many techniques available but the main selection of techniques for battery testing are revolve around electrochemical impedance spectroscopy, charging/discharging and pulsing techniques meant to mimic drive cycles, for example.  We also have ancillary techniques such as PITT/GITT.  

Gamry's EIS software also includes a powerful Autofit™ routine that takes the guesswork out of estimating initial parameter values in your battery model. You can view the video EIS of Lithium ion Battery.  This can be very valuable when processing EIS data.  Gamry's multisine techniques called OptiEIS and CombiEIS are not your standard multisine technique.  Gamry's multisine technique contains two unique algorithims for improving signal to noise ratio.  

Gamry Expertise

Gamry Instruments systems are used in a wide range of applications – from studying battery materials to partially assembled cells to full cells to stacks.  Below are several examples where people have studied anode or cathode failure mechanisms, generated general models for Li ion and lead acid batteries, investigated electrolytes and separators.  These are just a sampling of the type of work that you can do with our systems.  

Cycle aging of LiMn2O4-NMC/graphite – This electrochemical and physical characterization investigation shows that the most significant aging process was loss of lithium due to SEI-layer formation on the anode.  Layer formation is accelerated by transition metals coming from the cathode.  EIS reveals an increase in charge-transfer resistance of the cathode and serial resistance due to electrolyte decomposition. 

Link: http://dx.doi.org/10.1016/j.jpowsour.2013.11.080

Calendar aging of LiMn2O4-NMC/graphite – This is a partner paper to the one above.  In this investigation, researchers revealed that the most significant aging processes for cells aged at 4.2 V were loss of cycleable lithium, electrolyte decomposition and loss of active cathode material.  Cells aged at 4.0 V show less loss of lithium.  Interestingly, both anode and cathode showed decreases in charge transfer resistance. 

Link: http://dx.doi.org/10.1016/j.jpowsour.2014.02.019

Characterization of a novel separator material – In this investigations, researchers conformally coated a three-dimensional electrode using several diazonium salts.  These films shown to be pin-hole free through a series of redox-probe experiments and electrochemical impedance spectroscopy.  These results open a new class of diazonium salt monomers that will serve as useful building blocks for future exploration as separators in lithium batteries. 

Link: http://dx.doi.org/10.1021/cm501482h

Low-temperature charging of lithium ion cells – In this particular investigation, researchers studied low temperature charging of lithium ion cells in order to develop models for internal processing and prediction of aging effects using EIS.  The researchers then transformed these models into an on-board applicable form  for use in battery management systems in a second publication shown below this first one. 

Link One: http://dx.doi.org/10.1016/j.jpowsour.2013.12.022

Link Two: http://dx.doi.org/10.1016/j.jpowsour.2013.12.101

Development of a Generic Equivalent Circuit for High Power Lithium Ion Cells – Researchers used EIS measurements along with temperature and SOC to develop an equivalent circuit model that is then used to improve battery design and control algorithms. 

Link: http://dx.doi.org/10.1016/j.jpowsour.2010.12.107

State of Health (SOH) evaluation of lithium polymer batteries using EIS – In this particular paper, researchers used EIS to studies batteries in order to extract key parameters from an equivalent circuit that will allow them evaluate the SOH online or in service. 

Link: http://dx.doi.org/10.1016/j.energy.2015.05.148

Simplified equivalent circuit model for simulation of lead-acid batteries under load – Here researchers ran a series of EIS tests for four separate lead-acid batteries under load.  From these experiments researchers were able to derive a simplified equivalent circuit model for the lead-acid battery that allows them to understand degradation processes within the battery itself. 

Link: http://dx.doi.org/10.1016/j.enconman.2011.02.013

Testing of batteries in conjunction with supercapacitors for electrified vehicles – EIS was used to study supercapacitors that placed in parallel with either lithium ion or lead-acid batteries. 

Link: http://dx.doi.org/10.1016/j.jpowsour.2012.10.087

Recommended

Recommended setups

When testing materials and coin cells, the Interface 1000E is our recommended setup.  For increased capacities or current needs we recommend the Interface 5000P or 5000E or the Reference 3000.   For larger format cells we recommend the Reference 3000 or 3000AE in conjunction with our Reference 30K Booster.  When high-throughput battery testing is needed we recommend our multichannel setup.  Any of our potentiostats can be configured into a multichannel setup, giving you the greatest flexibility possible. 

We also have several small accessories available that can be very useful.  For materials testing we have both the Lithium Ion Battery Materials Cell and the Dr. Bob's Cell.  We also have two very useful battery holders that utilize four-probe contacts to give the best impedance result possible.  Four-probe connections are necessary to eliminate the effect of contact resistance when connecting the sense leads to your cells.  Not utilizing four-probe connections can significantly affect your results.  Our battery holders have also been designed to reduce mutual inductance between the current-carrying cables and the sense cables.