Battery design for achieving end-of-life indication during electrical discharge

An electrochemical cell comprising:

• a) an anode means provided as a first continuous sheet comprising lithium;
• b) a cathode means comprising cathode active material, wherein the cathode means is provided as a second continuous sheet having at least two cathode portions, each cathode portion having a different thickness and a combined surface area substantially similar to and facing the lithium anode means and wherein the anode means and the cathode means are operatively associated with respect to each other in a jellyroll configuration;
• and
• c) an electrolyte operatively associated with the anode means and the cathode means to generate an output voltage in an external electrical circuit connected to the cell during an electrochemical reaction, wherein the cathode portion having the lesser thickness is rendered electrochemically unreactive prior to the other cathode portion having the greater thickness to produce a step change in the output voltage from a higher output voltage to a lower output voltage.

An electrochemical cell comprising:

• a) first electrode means comprising a first electrode active material and having at least a first and a second major surfaces of dissimilar surface areas prior to cell discharge;
• b) a second electrode means comprising a second electrode active material, wherein the second electrode means has at least two second electrode portions, each second electrode portion having a substantially similar thickness and having dissimilar surface areas facing a similarly sized surface area of a respective one of the first and second major surfaces of the first electrode means prior to cell discharge;
• and
• c) an electrolyte operatively associated with the first and second electrode means to generate an output voltage in an external electrical circuit connected to the cell during an electrochemical reaction, wherein the one second electrode portion having the lesser surface area is rendered electrochemically unreactive prior to the other second electrode portion having the greater surface area to produce a step change in the output voltage from a higher output voltage to a lower output voltage.

An electrochemical cell comprising:

• a) a first electrode means comprising a first electrode active material, wherein the first electrode means has at least a first and a second major surfaces;
• b) a second electrode means comprising a second electrode active material, wherein the second electrode means has at least two second electrode portions, each second electrode portion including a known ratio of the second electrode active material mixed with non-electrode active material and positioned facing respective ones of the first and second major surfaces of the first electrode means, wherein one of the second electrode portions comprises a lesser ratio of the second electrode active material to the non-electrode active material than the other second electrode portion comprising the second electrode means;
• and
• c) an electrolyte operatively associated with the first and second electrode means to generate an output voltage in an external electrical circuit connected to the cell during an electrochemical reaction, wherein the one second electrode portion having the lesser ratio of the second electrode active material to the non-electrode active material is rendered electrochemically unreactive prior to the other second electrode portion having the greater ratio of the second electrode active material to the non-electrode active material resulting in a step change in the output voltage from a higher output voltage to a lower output voltage.

An electrochemical cell comprising:

• a) an anode means comprising an alkali metal and having at least a first and a second major surfaces;
• b) a cathode means operatively associated with the anode means and comprising cathode active material formed into at least two cathode portions, each cathode portion having a known ratio of the cathode active material mixed with non-cathode active material and positioned facing respective ones of the major surfaces of the anode means, wherein one of the cathode portions comprises a lesser ratio of the cathode active material to the non-cathode active material than the other cathode portion having a greater ratio of the cathode active material to the non-cathode active material;
• and
• c) an electrolyte operatively associated with the anode means and the cathode means to generate an output voltage in an external electrical circuit connected to the cell during an electrochemical reaction, wherein the one cathode portion having the lesser ratio of cathode active material to the non-cathode active material is rendered electrochemically unreactive by saturating intercalation of the anode active material prior to the other of the cathode portions having the greater ratio of the cathode active material to the non-cathode active material resulting in a proportionate reduction in the interelectrode working capacity by a factor related to the total quantity of the cathode active material comprising the cathode means contributed by the one cathode portion having the lesser ratio.

An electrochemical cell comprising:

• a) a lithium anode having at least a first and second major surfaces;
• b) a cathode means operatively associated with the anode and consisting of cathode active material formed into at least two cathode portions, each having a known ratio of the cathode active material mixed with non-cathode active material and positioned facing respective ones of the major surfaces of the lithium anode, wherein one of the cathode portions comprises a lesser ratio of the cathode active material than the other cathode portion having a greater ratio of the cathode active material to the non-cathode active material;
• and
• c) an electrolyte operatively associated with the anode and the cathode means to generate an output voltage in an external electrical circuit connected to the cell during an electrochemical reaction, wherein the one cathode portion having the lesser ratio of cathode active material to the non-cathode active material is rendered electrochemically unreactive by saturating intercalation of the anode active material prior to the other cathode portion having the greater ratio of the cathode active material to the non-cathode active material resulting in a proportionate reduction in the interelectrode working capacity by a factor related to the total quantity of the cathode active material comprising the cathode means contributed by the cathode portion having the lesser percentage.

A secondary electrochemical cell comprising:

• a) a cathode means capable of intercalating and deintercalating an alkali metal;
• b) an anode means comprising at least two anode portions, each anode portion capable of intercalating and deintercalating the alkali metal, wherein the two anode portions are positioned facing opposed portions of the cathode means with one of the anode portions having a lesser capacity to intercalate and deintercalate the alkali metal than the other anode portion having a greater capacity;
• and
• c) an electrolyte operatively associated with the cathode means and anode means to generate an output voltage in an external electrical circuit connected to the cell during an electrochemical reaction, wherein when the cell is in a charged condition and during electrical discharge, the one anode portion having the lesser capacity is rendered electrochemically unreactive by deintercalation of alkali metal ions moving through the electrolyte to the cathode means prior to the other anode portion having the greater capacity resulting in a step change in the output voltage from a higher output voltage to a lower output voltage and wherein the secondary electrochemical cell is rechargeable with the alkali metal ions intercalated into the cathode means being transferrable back to the anode means to reintercalate therein.