Hermetically sealed lithium-ion secondary electrochemical cell
AssigneeWilson Greatbatch Ltd.
InventorsDavid M. Spillman, Hong Gan, Esther S. Takeuchi
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Abstract
A rechargeable alkali metal electrochemical cell, and preferably a lithium-ion secondary cell, constructed of low magnetic susceptibility materials, is described. The non-magnetic characteristics enable the secondary cell to be used within the confines of a Magnetic Resonance Imaging system. The cell includes an electrolyte solution comprising ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate.
Claims27
A secondary electrochemical cell, which comprises:
- a) a casing;
- b) a negative electrode comprising a negative electrode active material which intercalates with an alkali metal;
- c) a positive electrode comprising a positive electrode active material which intercalates with the alkali metal, wherein the negative electrode and the positive electrode are electrochemically associated with each other housed in the casing, and wherein a periphery of the positive electrode is completely bounded by a periphery of the negative electrode to prevent alkali metal from plating as the cell is repeatedly cycled between a charged and a discharged condition;
- and
- d) an electrolyte solution activating the negative and positive electrodes, wherein the electrolyte comprises about 45% ethylene carbonate, about 22% dimethyl carbonate, about 24.8% ethylmethyl carbonate and about 8.2% diethyl carbonate, by volume.
An electrochemical cell, which comprises:
- a) a casing of a material having a magnetic susceptibility of at least about 182×106, or greater;
- b) a negative electrode which intercalates with lithium;
- c) a positive electrode comprising a lithiated electrode active material, wherein the negative electrode and the positive electrode are electrochemically associated with each other housed in the casing;
- and
- d) an electrolyte solution activating the negative and the positive electrodes, the electrolyte including a lithium metal salt dissolved in a quaternary, nonaqueous carbonate solvent mixture consisting of about 45% ethylene carbonate, 22% dimethyl carbonate, about 24.8% ethylmethyl carbonate and about 8.2% diethyl carbonate, by volume.
A method for providing a secondary electrochemical cell, comprising the steps of:
- e) providing a casing of a material having a magnetic susceptibility of at least about 182×106, or greater;
- f) providing a negative electrode which intercalates with an alkali metal;
- g) providing a positive electrode comprising a positive electrode active material which intercalates with the alkali metal;
- h) housing the negative and the positive electrodes inside the casing electrochemically associated with each other and wherein a periphery of the positive electrode is completely bounded by a periphery of the negative electrode to prevent alkali metal from plating as the cell is repeatedly cycled between a charged and a discharged condition;
- and
- i) activating the negative and positive electrodes with an electrolyte comprising about 45% ethylene carbonate, about 22% dimethyl carbonate, about 24.8% ethylmethyl carbonate and about 8.2% diethyl carbonate, by volume.
Dependencies are inferred from the claim text.