High energy density rechargeable cell for medical device applications
OwnerEsther S. Takeuchi, Randolph Leisinginventors
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Abstract
A re-balanced lithium ion secondary cell, particularly one comprising LiCoO2 cathode active material, is described. The preferred anode material is carbonaceous, and the couple is balanced to a ratio of the cathode active material to the anode material of from about 1.35 to about 2.25. This significantly improves the energy density of the secondary cell over that known by the prior art by increasing the charge voltage to at least 4.4V.
Claims22
An electrochemical cell, which comprises:
- a) a negative electrode comprising an anode material capable of intercalating and de-intercalating an alkali metal;
- b) a positive electrode comprising a cathode active material capable of intercalating and de-intercalating the alkali metal;
- and
- c) an electrolyte activating the negative electrode and the positive electrode, wherein a ratio of the cathode active material to the anode material is from about 1.35 to about 2.25.
An electrochemical cell, which comprises:
- a) a negative electrode comprising a carbonaceous material capable of intercalating and de-intercalating lithium;
- b) a positive electrode comprising a lithiated cathode active material capable of intercalating and de-intercalating lithium;
- and
- c) an electrolyte activating the negative electrode and the positive electrode, wherein a ratio of the cathode active material to the anode material is from about 1.35 to about 2.25.
An electrochemical cell, which comprises:
- a) a negative electrode comprising a carbonaceous material capable of intercalating and de-intercalating lithium;
- b) a positive electrode comprising lithium cobalt oxide;
- and
- c) an electrolyte activating the negative electrode and the positive electrode, wherein a ratio of the cathode active material to the anode material provided a cathode capacity of from about 165 mAh/gram to about 225 mAh/gram at a rate of about C/5.
An electrochemical cell, which comprises:
- a) a negative electrode comprising a carbonaceous material capable of intercalating and de-intercalating lithium;
- b) a positive electrode comprising lithium cobalt oxide;
- and
- c) an electrolyte activating the negative electrode and the positive electrode, wherein a ratio of the cathode active material to the anode material provided a cathode capacity of from about 165 mAh/gram to about 245 mAh/gram at a rate of about C/50.
In an implantable medical device comprising an electrochemical cell which is capable of powering the device, the improvement in the cell which comprises:
- a) a negative electrode comprising a carbonaceous material capable of intercalating and de-intercalating lithium;
- b) a positive electrode comprising a lithiated cathode active material capable of intercalating and de-intercalating lithium;
- and
- c) an electrolyte activating the negative electrode and the positive electrode, wherein a ratio of the cathode active material to the anode material is from about 1.35 to about 2.25.
A method for providing electrical energy, comprising the steps of:
- a) providing an electrochemical cell comprising the steps of:
- i) providing a negative electrode comprising a carbonaceous material capable of intercalating and de-intercalating lithium;
- ii) providing a positive electrode comprising a lithiated cathode active material capable of intercalating and de-intercalating lithium;
- iii) housing the negative electrode and the positive electrode in a casing;
- and
- iv) activating the negative electrode and the positive electrode with an electrolyte;
- b) connecting the cell to an external load;
- and
- c) powering the load with the cell.
Dependencies are inferred from the claim text.