Centre National De La Recherche Scientifique

Batscap

University of Hawai'i

Blue Solutions

Matthieu Dubarry

Marc Deschamps

Dominique Guyomard

Joël Gaubicher

Benoit Morel

Arnaud Devie

Philippe Moreau

In one aspect, an embodiment of this invention comprises an apparatus for updating an active fuel gauge of a battery cell. The apparatus comprises a memory, a sensor, and a processor. The memory stores data regarding an active fuel gauge of the battery cell based on a first voltage and state of charge (SOC) relationship. The processor receives first, second, and third resting voltage measurements at different times. The processor calculates differences in capacity between pairs of the resting voltage measurements based on the first voltage and state of charge (SOC) relationship. When the differences are equal the reference capacity difference, the processor identifies an estimate of a remaining capacity of the battery cell corresponding with the active fuel gauge. When the differences are not equal to the reference capacity difference, the processor updates the active fuel gauge based on an identified second voltage and SOC relationship.

Methods and apparatus for updating a fuel gauge and estimating state of health of an energy storage cell

The invention relates to a lithium vanadium oxide which corresponds to the formula LiVO(0.1&#x2266;&#x3b1;&#x2266;0.25). It is composed of agglomerates of small needles having a length l from 400 to 1000 nm, a width w such that 10&#x3c;l/w&#x3c;100 and a thickness t such that 10&#x3c;l/t&#x3c;100. It is obtained by a process consisting in preparing a precursor gel by bringing &#x3b1;-VOand a Li precursor into contact in amounts such that the ratio of the concentrations [VO]/[Li] is between 1.15 and 1.5 and in subjecting the gel to a heat treatment comprising a first stage at 80&#xb0; C.-150&#xb0; C. for 3 h to 15 days and a second stage between 250&#xb0; C. and 350&#xb0; C. for 4 min to 1 hour, under a nitrogen or argon atmosphere. It is useful as an active material of a positive electrode.

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The invention relates to a method for preparing a lithium and vanadium oxide and the thus obtained products. The method comprises preparing a precursor gel by reacting hydrogen peroxide with &#x3b1;-VOin an aqueous medium in the presence of a lithium precursor and exposing the gel to a heat treatment in an oxidant atmosphere at a temperature ranging from 260&#xb0; C. to 580&#xb0; C. A compound of a formula LiVO, (0.1&#x3c;x&#x3c;0.25) comprises needle-shaped grains having a bimodal distibution, wherein the length (L) of the first distribution needles ranges from 10 to 50 &#x3bc;m and the length (L) of the second distribution needles ranges from 1 to 10 &#x3bc;m.

The invention relates to the preparation of an optionally carbonaceous &#x3b3;-LiVOmaterial. The process consists in preparing a composition formed of carbon and of precursors of Li and of V and in subjecting it to a heat treatment. The composition is prepared by bringing carbon, &#x3b1;-VOand a Li precursor into contact in amounts such that the ratio of the [VO]/[Li] concentrations is between 0.95 and 1.05 and the carbon is in excess of at least 25% with respect to the stoichiometry. The heat treatment is carried out in two stages: a first stage at a temperature between 90&#xb0; C. and 150&#xb0; C. for a time of 1 to 12 hours and a second stage at a temperature between 420&#xb0; C. and 500&#xb0; C. for a time of between 10 min and 1 hour, under a nitrogen or argon atmosphere or under vacuum. Applications: positive electrode active material.

The invention relates to a nanostructured material. The material is a nanostructured carbonaceous material composed of agglomerates of small needles of LiVOand of &#x3b2;-LiVO(0.1&#x2266;&#x3b1;&#x2266;0.25 and 0.03&#x2266;x&#x2266;0.667) surrounded by a noncontinuous layer of spherical carbon particles. It is obtained by a process consisting in preparing a carbonaceous precursor gel by bringing carbon, &#x3b1;-VOand a Li precursor into contact in amounts such that the ratio of the [VO]/[Li] concentrations is between 1.15 and 1.5 and that the (carbon)/(carbon+VO+Li precursor) ratio by weight is from 10 to 15 and in subjecting the gel to a heat treatment comprising a 1st stage at 80&#xb0; C.-150&#xb0; C. for 3-12 h and a 2nd stage between 300&#xb0; C. and 350&#xb0; C. for 10 min to 1 hour, under an nitrogen or argon atmosphere. Applications: positive electrode active material.

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Honolulu, HI, United States of America

Matthieu Dubarry