Lightweight laminated grid for lead acid-storage batteries

• US 4,286,362 A
• Filed: 01/28/1980
• Issued: 09/01/1981
• Est. Priority Date: 02/09/1979
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Hammar, Richard H., Harvey, Douglas J.
• Primary Examiner(s): Culver, Horace M.
• Application Number:
  US06/116,362
• Time in Patent Office: 582 Days
• Field of Search: 29/2, 29/6.1, 29/6.2, 429/234, 429/241, 429/243, 429/244
• US Class Current: 29/2
• CPC Class Codes: H01M 4/68 for use in lead-acid accumulators
• CPC Class Codes: H01M 4/745 Expanded metal
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/10 Battery-grid making

Abstract

Lightweight grids for lead-sulfuric acid type storage batteries are characterized by their laminated reticulated open meshed portions for retaining chemically active, lead-based paste materials. The laminated portions comprise a support layer of a rigid or semi-rigid plastic, an electrically conductive lead foil layer coextensive with the plastic layer, and a sulfuric acid resistant adhesive bonding layer between the plastic support and foil layers. In a preferred embodiment, the grid wires and nodes are twisted relative to the principal plane of the grid so that the lead foil layer is oriented to face the grid header portion and act as a ledge for retaining a desired battery paste. Such laminated grids may be rapidly and inexpensively formed by expanded metal processes of the type used to make battery grids made entirely of lead.

Claims

1. A method of making a lightweight laminated grid for a lead-acid storage battery comprising the steps of:

providing a trilaminate sheet comprising a support layer of a synthetic polymeric plastic bonded to a coextensive layer of lead or lead alloy foil by an interposed layer of adhesive;

forming a plurality of straight, parallel rows of intermittent slits through the thickness of said sheet, the spacing between said rows ultimately defining grid wire portions and the spacing between the slits of a said row ultimately defining node portions which interconnect said wire portions; and

stretching said sheet to open said slits and form an open mesh network of grid wire portions and interconnecting nodes, and twisting the network such that the foil layer forms ledges which face the grid header for holding battery paste.

2. A method of making a substantially flat lightweight paste-retaining grid for a lead-acid type storage battery comprising the steps of:

adhesively bonding a layer of lead or lead alloy foil to a coextensive supporting layer of a synthetic polymeric material to form a trilaminate sheet;

forming a plurality of straight parallel rows of intermittent slits through said trilaminate, the slit portions of said row being located opposite the unslit portions of an adjacent row;

expanding the slit trilaminate to form an open mesh network of grid wires interconnected by nodes;

flattening said expanded network into the plane of the grid, the continuous foil layer of said wires and nodes forming ledges oriented at an angle out of the plane and facing the grid header for retaining a battery paste.

3. A method of making a lightweight battery grid for a lead-acid type storage battery comprising the steps of:

adhesively bonding a layer of lead or lead alloy foil to a coextensive layer of a thermoplastic synthetic polymer to form a trilaminate;

forming a plurality of straight parallel rows of intermittent slits through said trilaminate;

heating said trilaminate to a temperature below its melting point whereat the elastic memory of the thermoplastic polymer is reduced;

spreading the slit trilaminate while substantially at said temperature to form an open mesh network of grid wires interconnected by nodes, said wires and nodes being twisted out of the principal plane of the trilaminate to form a plurality of electrically connected foil-lined ledges facing the grid header for retaining battery paste.