Bipolar battery construction

• US 5,618,641 A
• Filed: 12/03/1993
• Issued: 04/08/1997
• Est. Priority Date: 12/03/1993
• Status: Expired due to Fees

• Current Assignee: Bipolar Power Corporation
• Original Assignee: Bipolar Power Corporation
• Inventors: Arias, Jeffrey L.
• Primary Examiner(s): Fourson, George
• Assistant Examiner(s): EVERHART, CARIDAD
• Application Number:
  US08/161,970
• Time in Patent Office: 1,222 Days
• Field of Search: 429/210, 429/66, 429/204, 429/54, 429/152, 429/159, 29/623.2
• US Class Current: 429/210
• CPC Class Codes: H01M 10/0413 Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes
• CPC Class Codes: H01M 10/0418 with bipolar electrodes
• CPC Class Codes: H01M 10/0468 Compression means for stacks of electrodes and separators
• CPC Class Codes: H01M 10/12 Construction or manufacture
• CPC Class Codes: H01M 10/16 Suspending or supporting electrodes or groups of electrodes in the case
• CPC Class Codes: H01M 10/18 with bipolar electrodes
• CPC Class Codes: H01M 4/66 Selection of materials
• CPC Class Codes: H01M 50/186 characterised by the disposition of the sealing members
• CPC Class Codes: H01M 50/193 Organic material
• CPC Class Codes: H01M 50/325 comprising deformable valve members, e.g. elastic or flexible valve members
• CPC Class Codes: H01M 6/48 with bipolar electrodes
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/4911 including sealing

Abstract

The Bipolar Battery Construction disclosed and claimed above solves the problem of constructing a bipolar battery (11,12) with a desired, uniform, constant, pressure between each bipolar plate (20) and separator (30) in the battery cell stack (48). The provision of such a pressure dramatically increases battery life, and increases the power of the cell stack (48). Compressive force is provided by spring-loaded clamping internal to the battery (11,12). A sealed battery case (52) provides common confinement of gases and vapors from all cells (58), minimizing battery sealing requirements. An inhibitor device (80,81) is provided for minimizing or eliminating leakage current between adjacent battery cells (58) through electrolyte (32), avoiding self-discharge of the cells (58). Insulation (54) minimize temperature gradients in the cell stack (48) which assures uniform and stable performance.

Claims

1. A lead-acid battery apparatus for producing electrical energy, comprising:

a battery stack including a plurality of bipolar cells, said battery stack being bounded at one end by a first end plate current collector and an opposite end by a second end plate current collector, said second end plate current collector being of opposite polarity to said first end plate current collector;

each of said plurality of bipolar cells including two bipolar plates, each having an upper surface, a lower surface, peripheral edges, and a thickness;

said upper surface coated to an area adjacent said peripheral edges with a positive active material and said lower surface coated to adjacent said peripheral edges with a negative active material;

a separator including an absorbed electrolyte separating said positive active material from said negative active material, said peripheral edges defining an open cavity

each of said plurality of bipolar plates coated with an inhibitor which inhibits leakage current through said electrolyte bridging between any two of said plurality of bipolar cells generally adjacent;

a compression element having a plurality of threaded bolts, a plurality of calibrated springs and a plurality of threaded nuts, a head of each of said threaded bolts bearing on said first end plate and a grip of each one of said threaded bolts passing axially adjacent said battery stack and through one of said calibrated springs, a first end of said calibrated springs bearing on said second end plate in opposition to said head and each of said nuts being threaded against a second end of each of said calibrated springs, creating the pressure by compressing said calibrated springs;

said compression element being disposed internally in said lead-acid battery apparatus, operating to apply a substantially uniform pressure on each one of said plurality of bipolar places and each said separator in each of said plurality of bipolar cells; and

a container having a gas-tight case which prevents escape of gas, vapor and liquid, operating to confine said battery stack and said compression element.

2. An apparatus as claimed in claim 1 in which said inhibitor comprises a surface coating of tantalum disposed upon said upper surface, and upon said thickness (t) of each one of said plurality of bipolar plates.

3. An apparatus as claimed in claim 1 in which said inhibitor comprises a surface coating of zirconium disposed upon said upper surface, upon said lower surface and upon said thickness (t) of each one of said plurality of bipolar plates.

4. An apparatus as claimed in claim 1 in which said inhibitor comprises a hydrophobic surface coating (80a) disposed upon said plurality of peripheral edges and upon said thickness (t) of each one of said plurality of bipolar plates.

5. An apparatus as claimed in claim 1 in which said inhibitor comprises an electrolyte dam.

6. An apparatus as claimed in claim 4 in which said hydrophobic surface coating is Teflon™

.

7. An apparatus as claimed in claim 4 in which said hydrophobic surface coating is wax.

8. An apparatus as claimed in claim 4 in which said hydrophobic surface coating is a glassy metal oxide.

9. An apparatus as claimed in claim 4 in which said hydrophobic surface coating is polyethylene.

10. An apparatus as claimed in claim 5 in which said electrolyte dam comprises a continuous hydrophobic sponge disposed upon said plurality of peripheral edges of each one of said plurality of bipolar plates.

11. An apparatus as claimed in claim 5 in which said electrolyte dam comprises an upturned edge of each of said plurality of peripheral edges of each one of said plurality of bipolar plates.

12. An apparatus as claimed in claim 5 in which said electrolyte dam comprises a continuous rim disposed on each of said plurality of peripheral edges of each one of said plurality of bipolar plates.

13. An apparatus as claimed in claim 5 in which said electrolyte dam comprises a flexible, continuous hydrophobic bead, said flexible, continuous hydrophobic bead being affixed to each of said plurality of peripheral edges and said thickness (t) of each one of said plurality of bipolar plates.

14. A bipolar battery apparatus, comprising:

a housing, defining internal surfaces with a gas-tight chamber, said housing also defining a first electrode area and a second electrode area;

a stack of bipolar battery elements, said bipolar battery elements including a plurality of bipolar battery assemblies, each including a bipolar plate, a positive active material, a separator material and a negative active material, a first surface of said stack bounded by a non-movable member which defines said first terminal and is electrically connected to said first terminal, said non-movable member being fixed relative to said housing such that it cannot move relative to said housing; and

a second biasing element, defining a surface which biases a second, opposite side of said battery plates, said second biasing element including a compression element which allows said second element to move relative to said housing, said second element pressing against said second surface by a predetermined amount to press said second surface relative to said non movable member.

15. Apparatus as in claim 14 wherein said gas tight chamber includes a moving seal around said second electrode area, said moving seal allowing said second terminal to move relative to said case.

16. Apparatus as in claim 14 wherein said plate includes at least one spring element, pressing against a pressing surface, said pressing surface pressing against one of said positive active material and said negative active material.

17. A bipolar lead-acid battery comprising:

a housing having internal surfaces defining a closed chamber, having a gas-tight case which prevents escape of gas, vapor and liquid therefrom;

a plurality of bipolar battery cells;

said plurality of bipolar battery cells arranged in a battery stack in said housing;

each of said bipolar battery cells assembled in layers in said battery stack;

a first surface, coupled against a first surface of the battery stack, said first surface being immovable;

a fixed terminal connected to said first surface;

a second compression surface, including a bias surface biasing against said housing, said second surface being movable and pressing against a second surface of said battery stack; and

a movable terminal, connected to said second surface, said movable terminal further including a sliding gas type connection to prevent gas from escaping from said housing when said second surface is moved.