Investigation of Failure Processes in Porous Battery Substrates: Part I—Experimental Findings

Experimental findings are presented which demonstrate the coupled transport, mechanical and morphological changes in porous battery materials when they are cycled electrochemically. These materials, comprised of a mixture of powdered nickel and nickel fiber, act as substrates in nickel-metal hydride (NiMH) cells, and function as porous, conductive containment for positive-plate active material. They can offer substantial weight and cost savings over more traditional sintered or foam materials, provided they can be designed to produce good conductivity over many (>500) electrochemical cycles. This study represents an expansion of previous work by the authors, which had established some key differences in the behavior of substrate materials for a small number of cells. Here, these difference are validated with a greater variety and number of electrochemical/material experiments, along with a parallel study on morphological changes. In the second paper in this series (Cheng et al., 1999b), transport and mechanics models are presented to explain the observed differences, using microstructural models based on observations in this study.

Download Full-text

Recovery of Rare Earth Oxide from Waste NiMH Batteries by Simple Wet Chemical Valorization Process

Metals ◽

10.3390/met9111151 ◽

2019 ◽

Vol 9 (11) ◽

pp. 1151 ◽

Cited By ~ 3

Author(s):

Nak-Kyoon Ahn ◽

Basudev Swain ◽

Hyun-Woo Shim ◽

Dae-Weon Kim

Keyword(s):

Rare Earth ◽

Active Material ◽

Rare Earth Oxide ◽

Recovery Process ◽

Sulfate Solution ◽

Reaction Process ◽

Nickel Metal ◽

Nickel Metal Hydride ◽

Wet Chemical ◽

Almost All

Nickel metal hydride (NiMH) batteries contain a significant amount of rare earth metals (REMs) such as Ce, La, and Nd, which are critical to the supply chain. Recovery of these metals from waste NiMH batteries can be a potential secondary resource for REMs. In our current REM recovery process, REM oxide from waste NiMH batteries was recovered by a simple wet chemical valorization process. The process followed the chemical metallurgy process to recover REM oxides and included the following stages: (1) H2SO4 leaching; (2) selective separation of REM as sulfate salt from Ni/Co sulfate solution; (3) metathesis purification reaction process for the conversion REM sulfate to REM carbonate; and (4) recovery of REM oxide from REM carbonate by heat treatment. Through H2SO4 leaching optimization, almost all the metal from the electrode active material of waste NiMH batteries was leached out. From the filtered leach liquor managing pH (at pH 1.8) with 10 M NaOH, REM was precipitated as hydrated NaREE(SO4)2·H2O, which was then further valorized through the metathesis reaction process. From NaREE(SO4)2·H2O through carbocation, REM was purified as hydrated (REM)2CO3·H2O precipitate. From (REM)2CO3·H2O through calcination at 800 °C, (REM)2O3 could be recovered.

Download Full-text

Investigation of Failure Processes in Porous Battery Substrates: Part II—Simulation Results and Comparisons

Journal of Engineering Materials and Technology ◽

10.1115/1.2812409 ◽

1999 ◽

Vol 121 (4) ◽

pp. 514-523 ◽

Cited By ~ 16

Author(s):

X. Cheng ◽

C. Wang ◽

A. M. Sastry ◽

S. B. Choi

Keyword(s):

Mechanical Properties ◽

Morphological Changes ◽

Porous Fiber ◽

Nickel Metal ◽

Material Microstructure ◽

Nickel Metal Hydride ◽

Fiber Networks ◽

Real Material ◽

Nimh Battery ◽

Torsion Springs

Models are presented for the evolution of transport and mechanical properties of nickel-metal hydride (NiMH) battery substrates. In the first paper in this series (Wang et al., 1999), conductive losses and enhancement of mechanical properties in these materials were quantified experimentally. These were qualitatively shown to be related to observed morphological changes in the substrate materials. Here, an evolution hypothesis for changes in these structures is presented, along with a simplified approximation of the real material microstructure (porous fiber/powder nickel network) with a tractable simulation geometry (porous fiber networks). Transport and mechanics models are then compared with experimental results, with stochastically-arranged fibers approximated as conductive beams connected by elastic torsion springs. Both quantitative and qualitative agreement are found with the models. Limitations of the approaches proposed are also discussed, along with the consequences of the simplifications of geometry for analysis.

Download Full-text

Studies on hydride-forming alloys as the active material of a metal hydride electrode for a nickel metal hydride cell

The Twelfth Annual Battery Conference on Applications and Advances ◽

10.1109/bcaa.1997.574075 ◽

2002 ◽

Author(s):

N.S. Lim ◽

G.R. Zelter ◽

D.U. Allison ◽

J.J. Reilly ◽

S. Srinivasan ◽

...

Keyword(s):

Metal Hydride ◽

Active Material ◽

Nickel Metal ◽

Nickel Metal Hydride ◽

Metal Hydride Electrode

Download Full-text

Recovery of valuable metals from a spent nickel–metal hydride battery: Selective chlorination roasting of an anodic active material with CCl4 gas

Separation and Purification Technology ◽

10.1016/j.seppur.2013.08.008 ◽

2013 ◽

Vol 118 ◽

pp. 823-827 ◽

Cited By ~ 8

Author(s):

Toshihiro Kuzuya ◽

Shinji Hirai ◽

Vladimir V. Sokolov

Keyword(s):

Metal Hydride ◽

Active Material ◽

Nickel Metal ◽

Nickel Metal Hydride ◽

Selective Chlorination ◽

Valuable Metals ◽

Nickel Metal Hydride Battery ◽

Chlorination Roasting ◽

Hydride Battery

Download Full-text

Microstructural characterization of a cast RENi5-based alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151714 ◽

1993 ◽

Vol 51 ◽

pp. 1176-1177

Author(s):

G. M. Micha ◽

L. Zhang

Keyword(s):

Electron Microscopy ◽

Rare Earth ◽

Microstructural Characterization ◽

Binary Compound ◽

Nickel Metal ◽

Cast Material ◽

Nickel Metal Hydride ◽

Transmission Electron ◽

Cast Condition

RENi5 (RE: rare earth) based alloys have been extensively evaluated for use as an electrode material for nickel-metal hydride batteries. A variety of alloys have been developed from the prototype intermetallic compound LaNi5. The use of mischmetal as a source of rare earth combined with transition metal and Al substitutions for Ni has caused the evolution of the alloy from a binary compound to one containing eight or more elements. This study evaluated the microstructural features of a complex commercial RENi5 based alloy using scanning and transmission electron microscopy.The alloy was evaluated in the as-cast condition. Its chemistry in at. pct. determined by bulk techniques was 12.1 La, 3.2 Ce, 1.5 Pr, 4.9 Nd, 50.2 Ni, 10.4 Co, 5.3 Mn and 2.0 Al. The as-cast material was of low strength, very brittle and contained a multitude of internal cracks. TEM foils could only be prepared by first embedding pieces of the alloy in epoxy.

Download Full-text