# US 5,348,813 A · Battery charge indicator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,348,813 A - Document ID: US5348813A - Status: Granted - Kind: A - Application number: 07/760,200 - Filed: 1991-09-16 - Granted: 1994-09-20 - Earliest claimed: 1991-06-04 - Assignees: Display Matrix Corporation - Inventors: William Bohmer; Clark F. Bow - Web page: https://patentgrep.com/patent/US5348813A ## CPC - H01M 10/488: {Cells or batteries combined with indicating means for external visualization of the condition, e.g. by change of colour or of light density} - H01M 6/5044: {Cells or batteries structurally combined with cell condition indicating means} - H01M 6/505: {Cells combined with indicating means for external visualization of the condition, e.g. by change of colour or of light intensity} - H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) - H01M 50/213: adapted for cells having curved cross-section, e.g. round or elliptic (H01M50/209, H01M50/216 take precedence) - H01M 50/569: Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals (battery terminal connectors with integrated measuring arrangements G01R31/364) - Y02E 60/10: Energy storage using batteries - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A battery charge indicator is permanently incorporated into a battery to indicate the state of charge. In one embodiment, the indicator includes a compressible chamber which is filled with a viscous gel and which is exposed to the expandable cathode of the battery. As the battery discharges, the cathode expands thus causing the gel within the chamber to be extruded out through an outlet into a viewing channel in an overlying disk. The amount of gel flowing into the viewing channel is proportional to the amount of expansion of the cathode and, thus, indicates the amount of discharge and, conversely, the remaining life of the battery. In a second embodiment, a piston assembly is caused to move with a deformable end wall of the battery and indicia on the side wall of the piston assembly is viewed through a lens as a measure of the remaining amount of expect expansion of the cathode. ## Claims ### Claim 1 In combination, an alkaline battery including a housing having a closed end wall and a deformable end wall, an internally contained chemical cathode in said housing and an internally contained anode for generating an electrical current with said cathode while causing said cathode to expand against said deformable end wall; first means in contact with said deformable end wall for movement therewith; and second means for measuring the amount of movement of said first means to provide a visual indication of the remaining amount of expected expansion of said cathode. ### Claim 2 (depends on 1) The combination as set forth in claim 1 wherein said first means is a piston assembly aligned with a longitudinal axis of said housing. ### Claim 3 (depends on 2) The combination as set forth in claim 2 wherein said piston assembly includes a guide pin in contact with and extending longitudinally from said deformable end wall, and an annular disc mounted on said pin for movement therewith. ### Claim 4 (depends on 3) The combination as set forth in claim 3 wherein second includes a reflector having a central bore slidably receiving said disc of said piston assembly, a lens for viewing a reflection of a side face of said disc from said reflector, and a cover having at least one aperture overlying said lens for viewing said reflection. ### Claim 5 (depends on 4) The combination as set forth in claim 4 wherein said lens has a central bore slidably receiving said guide pin. ### Claim 6 (depends on 4) The combination as set forth in claim 4 wherein said disc has a flat peripheral wall, and said reflector is of annular shape to receive said disc with said peripheral wall recessed therein and with a reflective surface for reflecting an image of said peripheral wall during movement of said disc from within said reflector. ### Claim 7 (depends on 6) The combination as set forth in claim 6 wherein said lens is of annular shape and said cover has a plurality of circumferentially spaced apertures overlying said lens for viewing a reflection of said peripheral wall of said disc. ### Claim 8 (depends on 7) The combination as set forth in claim 7 wherein said peripheral wall has indicia to provide a visual reflected image corresponding the remaining amount of expected expansion of said cathode. ### Claim 9 (depends on 8) The combination as set forth in claim 8 wherein said indicia is a band of color. ### Claim 10 (depends on 9) The combination as set forth in claim 9 wherein said band is of non-uniform width about said peripheral wall. ### Claim 11 (depends on 6) The combination as set forth in claim 6 which further comprises a plurality of splines on said peripheral wall of said disc at uneven spacings and in contact with said reflector to impose a variable friction force on said disc to effect movement of said disc at an angle to said housing axis. ### Claim 12 (depends on 6) The combination as set forth in claim 6 wherein said peripheral wall of said disc is of varying length. ### Claim 13 (depends on 3) The combination as set forth in claim 3 wherein said guide pin has a face eccentric of said housing axis and in contact with said deformable end wall. ### Claim 14 (depends on 8) The combination as set forth in claim 8 wherein said indicia is a plurality of bands of color of different color from each other. ### Claim 15 In combination, an alkaline battery including a housing having an internally contained chemical cathode and anode for generating an electrical current with said cathode expanding in an amount proportional to the total current generated; first means defining a compressible chamber within said housing and having an outlet therefrom, said chamber being exposed to said cathode for compression thereby in response to and expansion of said cathode, the first means including a elongated flexible tube disposed in the housing, the elongated flexible tube having a transverse cross-section, a vicous gel in said chamber for expelling through said outlet in proportional response to compression of said chamber; and second means defining a viewing channel in communication with said outlet to receive said gel expelled from said chamber. ### Claim 16 (depends on 15) The combination as set forth in claim 15 wherein the transverse cross-section of the flexible tube is an asymmetrical transverse cross-section.