Anode cross-sectional characteristic gradient

Patent metadata

Field	Value
Publication number	US-2018261851-A1
Application number	US-201815896917-A
Country	US
Kind code	A1
Filing date	Feb 14, 2018
Priority date	Mar 10, 2017
Publication date	Sep 13, 2018
Grant date	—

Abstract

Various embodiments are directed to an electrochemical cell having a non-homogeneous anode. The electrochemical cell includes a container, a cathode forming a hollow cylinder within the container, an anode positioned within the hollow cylinder of the cathode, and a separator between the cathode and the anode. The anode defines a characteristic gradient between an interior portion of the anode and the outermost surface of the anode adjacent the separator. The characteristic gradient may be defined as, for example, an average active material particle size within the anode that changes as a function of the radial location within the anode or a surfactant concentration gradient that changes as a function of the radial location within the anode.

First claim

That which is claimed:

1 . An electrochemical cell comprising:
a container; a cathode forming a hollow cylinder and having a cathode outer surface adjacent an inner surface of the container and a cathode inner surface defining an interior portion of the cathode; an anode positioned within an interior portion of the cathode and formed of one or more materials, wherein the anode defines an anode outer surface adjacent the cathode inner surface and a central portion; a separator disposed between the anode outer surface and the cathode inner surface; and an electrolyte; wherein at least one of the materials of the anode defines a material characteristic that is gradient in a radial direction between a central portion of the anode and the anode outer surface.

2 . The electrochemical cell of claim 1 , wherein the characteristic gradient is continuous between the central portion of the anode and the anode outer surface.

3 . The electrochemical cell of claim 1 , wherein the characteristic gradient is defined by a first anode portion comprising the central portion of the anode and a second anode portion between the anode outer surface and the first anode portion, wherein the first anode portion comprises a first anode material composition defining a first anode characteristic and the second anode portion comprises a second anode material composition defining a second anode characteristic, and wherein the first anode material composition is different from the second anode material composition.

4 . The electrochemical cell of claim 1 , wherein the characteristic gradient is defined by a gradient in the average particle size of an active material between the central portion of the anode and the anode outer surface.

5 . The electrochemical cell of claim 4 , wherein the electrochemical cell is a primary alkaline electrochemical cell, and the active material comprises zinc.

6 . The electrochemical cell of claim 1 , wherein the characteristic gradient is defined by a gradient in an active material alloy between the central portion of the anode and the anode outer surface.

7 . The electrochemical cell of claim 6 , wherein the gradient in the active material alloy is defined between a first active material alloy in the central portion of the anode and a second active material alloy located in a portion of the anode adjacent the anode outer surface.

8 . The electrochemical cell of claim 1 , wherein the characteristic gradient is defined by a gradient in an active material concentration between the central portion of the anode and the anode outer surface.

9 . The electrochemical cell of claim 3 , wherein the first anode material composition comprises an active material having a first average particle size and the second anode composition comprises the active material having a second average particle size, wherein the first average particle size is different from the second average particle size.

10 . The electrochemical cell of claim 9 , wherein the first average particle size is smaller than the second average particle size.

11 . The electrochemical cell of claim 1 , where one of the anode materials comprises a surfactant, and wherein the characteristic gradient is defined by a concentration gradient of surfactant between the central portion of the anode and the anode outer surface.

12 . The electrochemical cell of claim 3 , where one of the anode materials comprises a surfactant, and wherein the first anode portion comprises a first concentration of the surfactant and the second anode portion comprises a second concentration of the surfactant, wherein the first concentration of the surfactant is different from the second concentration of the surfactant.

13 . The electrochemical cell of claim 11 , wherein the first concentration of the surfactant is lower than the second concentration of the surfactant.

14 . A method of forming an electrochemical cell, the method comprising:
providing a container; forming a cathode within the container, wherein the cathode is generally cylindrical and defining a cathode outer surface positioned adjacent an interior surface of the container and a cathode interior surface defining an inner portion of the cathode; positioning a separator within the inner portion of the cathode; and forming an anode comprising one or more material within the inner portion of the cathode on an opposite side of the separator, wherein the anode defines an anode outer surface adjacent the cathode inner surface and a central portion, wherein at least one of the materials of the anode defines a material characteristic that is gradient in a radial direction between the central portion and the outer surface.

15 . The method of claim 14 , wherein forming the first anode portion comprises extruding a first anode composition having a first average active material particle size into the inner portion of the cathode; and
forming the second anode portion comprises extruding a second anode composition having a second average active material particle size into the inner portion of the anode, wherein the second average active material particle size is smaller than the first average active material particle size.

16 . The method of claim 14 , wherein forming the first anode portion comprises extruding a first anode composition comprising a surfactant in a first concentration into the inner portion of the cathode; and
forming the second anode portion comprises extruding a second anode composition comprising the surfactant in a second concentration into the inner portion of the anode, wherein the first concentration is greater than the second concentration.

17 . The method of claim 14 , wherein forming the first anode portion and forming the second anode portion collectively comprise coextruding the first anode portion and the second anode portion.

18 . The method of claim 14 , wherein forming the first anode portion comprises:
extruding a first anode composition into the inner portion of the cathode; and extending a plunger into the inner portion of the cathode to mold the first anode portion to define the anode exterior surface and the anode interior surface; and forming the second anode portion comprises extruding the second anode portion into the inner portion of the anode.

Assignees

• Energizer Brands Llc

Inventors

• Huang Weiwei

Classifications

• H01M6/085 Primary

  of the reversed type, i.e. anode in the centre · CPC title

• H01M4/244

  Zinc electrodes · CPC title

• H01M4/364 Primary

  as mixtures · CPC title

• H01M6/045

  characterised by aqueous electrolyte · CPC title

• H01M4/9041

  Metals or alloys (H01M4/92 takes precedence) · CPC title