In Situ Investigation of the Volume Change in Li-ion Cell with Charging and Discharging

Abstract

Since battery performance is the main factor affecting on-orbit satellite operation, it is very important to understand the degradation mechanism of battery performance and operating conditions. In particular, a lithium ͑Li͒ ion cell used as a satellite power source may be subjected to high charge and discharge rates, and the cell volume change during the charge-discharge cycle might cause the mechanical degradation of the electrode. In this work, we used two in situ methods, load cell measurement and X-ray observation, to investigate the cell volume change of a commercial Li-ion polymer cell with charging and discharging An excess cell volume change that was delayed with respect to the change induced by the state of charge was observed at high charge and discharge rates. We attributed this phenomenon to the slow diffusion of Li ions in the electrode active materials and slow structural change in the outer region of the electrode particle. Furthermore, we deduced that the outer region of the electrode particle, rather than the inner region, was mainly responsible for the excess cell volume change.

Understanding Volume Change in Lithium-Ion Cells during Charging and Discharging Using In Situ Measurements

“…4 is that the strain decreases at the end of the charge as a function of the number of cycles at taper voltages above 4.05 V, in contrast to the strain increase observed at the end of the charge when using a taper voltage of 3.95 V. 15 In our previous paper, we attributed the strain increase at the end of the charge at a taper voltage of 3.95 V to slow lithium-ion diffusion in the electrode particles, which causes the lithium ions to be distributed heterogeneously within the electrode's active material, and ultimately causes the excess volume change. 19 The strain decrease at the end of the charge at taper voltages above 4.05 V may be explained by the schematic interpretation in Fig. 9a.…”

“…The cell-volume change may be explained by simultaneous volume expansion ͑contraction͒ of the graphite anode and LiCoO 2 cathode in the lithium-ion cell experiencing the charge ͑discharge͒ process, as described in our previous paper. 19 Figure 3 depicts the voltage trend at the end of the charge and discharge of five 50 Ah-class lithium-ion cells. The cycle-life testing was completed after 5170 cycles, corresponding to one year of LEO operation.…”

In Situ Stress Measurement Techniques on Li-ion Battery Electrodes: A Review

“…The variable thickness of a battery is commonly used to represent its dimensional change, the measurement of which can be obtained by using a linear voltage displacement transformer (LVDT) [3][4][5], a dilatometer [6], a thickness gauge [7], or X-ray observation [8]. In order to obtain three-dimensional changes of a cycling Li-ion battery, Leung et al [9] presented the application of three-dimensional digital image correlation for real-time displacement and strain analysis of a pouch-type battery.…”

Long-Term Operation of the Energy Storage System for Lunar and Planetary Missions

“…In the field of space technology, a number of current efforts are focused on applying them in spacecraft [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . One example is STENTOR, which attempted to demonstrate a SAFT 40 Ah lithium-ion battery system in a geo-stationary orbit [1][2][3][4][5][6][7][8][9][10][11] . The European piggy-back satellite 'PROBA' uses lithium-ion batteries produced by AEA using off-the-shelf lithium-ion cells from SONY 2) .…”

“…The same technology was also applied to European planetary missions such as the satellite 'Rosetta' and the 'Mars-Express' 2) . The Japan Aerospace Exploration Agency (JAXA) has been developing lithium-ion secondary cells for aerospace applications [5][6][7][8][9][10][11] . For scientific missions like interplanetary missions, lithium-ion secondary batteries have already been applied.…”