Positive battery terminal antenna ground plane

Patent metadata

Field	Value
Publication number	US-11031686-B2
Application number	US-201916687205-A
Country	US
Kind code	B2
Filing date	Nov 18, 2019
Priority date	Nov 1, 2016
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A positive terminal of a battery may act as an antenna ground plane for communicating battery status information. The positive terminal of the battery may include a first electrically conductive external surface with a first surface area. The negative terminal of the battery may include a second electrically conductive external surface with a second surface area less than the first surface area. An antenna impedance matching circuit may be electrically connected between a communication circuit, an antenna, and the positive terminal of the battery. Thus the positive terminal of the battery may act as a ground plane for the antenna.

First claim

What is claimed is:

1. An apparatus, comprising:
a positive terminal of a battery as a ground plane of an antenna, comprising a first electrically conductive external surface with a first surface area;
a negative terminal of the battery, comprising a second electrically conductive external surface with a second surface area;
an antenna impedance matching circuit, electrically connected between a communication circuit, an antenna, and the first electrically conductive external surface of the battery;
wherein the first surface area is greater than the second surface area.

2. The apparatus of claim 1 , wherein the first electrically conductive external surface electrically connects to a cathode of the battery, and the second electrically conductive external surface electrically connects to an anode of the battery.

3. The apparatus of claim 1 , wherein a ground plane of the communication circuit electrically connects to the negative terminal of the battery.

4. The apparatus of claim 1 , wherein the antenna impedance matching circuit comprises a balun configured to convert, for a first communication frequency, an input impedance of the impedance matching circuit to an output impedance of the impedance matching circuit.

5. The apparatus of claim 1 , wherein an electrical length of the first electrically conductive external surface is greater than 0.25 of a wavelength of a signal transmitted by the communication circuit into the antenna impedance matching circuit, and
wherein the electrical length of the first electrically conductive external surface is a physical length of the first electrically conductive external surface multiplied by the ratio of (i) the propagation time of the signal through the first electrically conductive external surface to (ii) the propagation time of the signal in free space over a distance equal to the physical length of the first electrically conductive external surface.

6. The apparatus of claim 5 , wherein the electrical length of the first electrically conductive external surface is configured to minimize a reflected power from the antenna back into the antenna impedance matching circuit as a result of the communication circuit transmitting the signal.

7. The apparatus of claim 4 , wherein the balun comprises a first winding and a second winding around a magnetic ferrite, wherein a first end of the first winding is electrically connected to the antenna, and a second end of the first winding is electrically connected to the positive terminal of the battery.

8. The apparatus of claim 7 , wherein a first end of the second winding is electrically connected to the communication circuit, and wherein a second end of the second winding is electrically connected to the antenna.

9. The apparatus of claim 1 , wherein the antenna impedance matching circuit comprises at least one of (i) a capacitor and (ii) an inductor, and wherein at least one of (i) the capacitor and (ii) the inductor are electrically connected between the communication circuit and the positive terminal of the battery.

10. The apparatus of claim 1 , wherein the battery is a primary alkaline battery.

11. A method, comprising:
providing a positive terminal of a battery as a ground plane of an antenna, comprising a first electrically conductive external surface with a first surface area;
providing a negative terminal of the battery, comprising a second electrically conductive external surface with a second surface area less than the first surface area;
providing an antenna impedance matching circuit; and
electrically connecting the antenna impedance matching circuit between the positive terminal of the battery, a communication circuit, and the antenna.

12. The method of claim 11 , comprising electrically connecting a ground plane of the communication circuit to the negative terminal of the battery.

13. The method of claim 11 , comprising providing a balun configured to convert an input impedance encountered by a signal transmitted by the communication circuit into the impedance matching circuit to an output impedance.

14. The method of claim 11 , comprising providing the first electrically conductive external surface with an electrical length greater than 0.25 of a wavelength of a signal transmitted by the communication circuit into the antenna impedance matching circuit.

15. The method of claim 14 , comprising providing the first electrically conductive external surface with an electrical length that minimizes a reflected power from the antenna back into the antenna impedance matching circuit as a result of the communication circuit transmitting the signal.

16. The method of claim 11 , wherein providing the antenna impedance matching circuit comprises providing at least one of (i) a capacitor and (ii) an inductor, and electrically connecting at least one of (i) the capacitor and (ii) the inductor between a communication circuit and the positive terminal of the battery.

17. The method of claim 11 , wherein:
the battery is a primary alkaline battery comprising a cathode connected to a metal battery can; and
electrically connecting the antenna impedance matching circuit between the positive terminal of the battery, the communication circuit, and the antenna comprises:
electrically connecting the antenna impedance matching circuit between the cathode of the primary alkaline battery, the communication circuit, and the antenna.

18. The method of claim 11 , wherein providing the antenna impedance matching circuit comprises:
providing a balun comprising a first winding and a second winding around a magnetic ferrite such that an output impedance of the balun approximates an input impedance of the antenna;
electrically connecting a first end of the first winding to the antenna; and
electrically connecting a second end of the first winding to the positive terminal of the battery.

19. The method of claim 18 , further comprising:
electrically connecting a first end of the second winding to the communication circuit; and
electrically connecting a second end of the second winding to the antenna.

Assignees

• Duracell Us Operations Inc

Inventors

• Bourilkov Jordan
• Riemer Joern
• Pavlinsky Robert
• Specht Steven J
• Turco George
• Coronado Sergio

Classifications

• H01M10/48

  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) · CPC title

• H01M10/425

  Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00) · CPC title

• H01M10/4264

  with capacitors · CPC title

• H01M2010/4271

  Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing · CPC title

• H01M2010/4278

  Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller · CPC title