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AssigneeGM Global Technology Operations LLC
InventorsAnil K. Sachdev, Mark W. Verbrugge, Xingcheng Xiao, Peter Maxwell Sarosi
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The gravimetric and volumetric efficiency of lithium ion batteries may be increased if high capacity materials like tin and silicon may be employed as the lithium-accepting host in the negative electrode of the battery. But both tin and silicon, when fully charged with lithium, undergo expansions of up to 300% and generate appreciable internal stresses which have potential to spall off material from the electrode on each discharge-charge cycle, resulting in a progressive reduction in battery capacity, also known as battery fade. A method of reinforcing such electrode materials by incorporating within them fiber reinforcements or shaped, elongated reinforcements fabricated of shape memory alloy is described. Electrode materials incorporating such reinforcements are less prone to damage under applied stress and so less prone to battery fade.
A reinforced negative electrode for a lithium ion battery, the electrode comprising a current collector carrying, on a surface, a shaped deposit of reinforced electrode material of predetermined thickness, the reinforced shaped electrode material deposit consisting of a metallic, lithium-accepting composition incorporating a layer of randomly-oriented, electrically-conducting, superelastic shape memory alloy reinforcement fibers or elongated-structures arranged as a tangled stack, the fiber or elongated-structure reinforcement layer having crevices and interstices, the lithium-accepting composition being deposited as a monolithic body which engages the reinforcement fibers or elongated-structures and at least partially occupies the crevices and interstices in the current collector surface-carried reinforcement layer to embed the reinforcement fibers or elongated-structures in the lithium-accepting composition;
A lithium ion battery comprising a reinforced negative electrode, the electrode comprising a current collector carrying, on a surface, a shaped deposit of reinforced electrode material of predetermined thickness consisting of a monolithic, metallic, lithium-accepting composition incorporating a reinforcement layer of randomly-oriented, fiber or elongated-structure-shaped, electrically-conducting, superelastic shape memory alloy reinforcements arranged as a tangled stack, the reinforcement layer having crevices and interstices, the reinforcement layer being filled with the monolithic, metallic, lithium-accepting, composition which engages the reinforcements and at least partially occupies the crevices and interstices in the current collector surface-carried reinforcement layer to embed the reinforcements in the monolithic, metallic, lithium-accepting composition;
A lithium ion battery comprising a reinforced negative electrode, the electrode comprising a current collector carrying, on a surface, a shaped deposit of reinforced electrode material of predetermined thickness, the reinforced shaped electrode material deposit consisting of a monolithic, metallic, lithium-accepting composition incorporating a layer, of between 10 micrometer and 50 micrometers thick, of randomly-oriented, electrically-conducting, superelastic shape memory alloy reinforcement fibers or elongated-structures arranged as a tangled stack, the fiber or elongated-structure layer having crevices and interstices, the crevices and interstices of the layer being at least partially filled with a coextensive layer of the monolithic, metallic, lithium-accepting, composition which engages the reinforcement fibers or elongated-structures in the current collector surface-carried reinforcement layer to embed the reinforcements in the electrode material;
Dependencies are inferred from the claim text.