Method and apparatus for continuously mixing battery pastes

Patent metadata

Field	Value
Publication number	US-10177369-B2
Application number	US-81259807-A
Country	US
Kind code	B2
Filing date	Jun 20, 2007
Priority date	Jun 20, 2006
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A process and apparatus for continuously mixing and applying paste to battery grids for use in lead-acid battery systems, in which particulate lead oxide, water and sulphuric acid are reacted in an elongated mixer having a mixing to conveying ratio of about 65:35 to 80:20 with controlled reaction temperature for an exit product temperature in the range of above 60° C. to about 80° C. Additives including reinforcing fibers can be added in an amount up to 0.6 wt % of the lead oxide and carbon and graphite powder can be added in an amount up to 6 wt % of the lead oxide.

First claim

The invention claimed is:

1. A method for continuously producing battery paste for use in a process for continuous production of pasted battery plates comprising feeding particulate lead oxide to an elongated reactor mixer having a plurality of mixing paddles and conveying paddles in series wherein the mixing paddles are structurally distinct from the conveying paddles, continuously injecting water and sulphuric acid sequentially to the lead oxide in the reactor mixer, rapidly mixing and reacting the sulphuric acid with the wetted particulate lead oxide to form a mixture for passage through the elongated reactor mixer for a controlled retention time in the reactor mixer under predetermined mixing and conveying conditions whereby the mixture is subjected to a ratio of mixing paddles to conveying paddles in the reactor mixer of about 65:35 to 80:20, and controlling the temperature of the mixture of lead oxide, water and sulphuric acid as it passes through the elongated reactor along the length of the reactor mixer for a maximum exit temperature of a discharge product in the range of above 60° C. to about 80° C., discharging the battery paste from the elongated reactor mixer for application to battery grids in a state in which the size of tribasic lead sulphate crystals in the battery paste is 5 microns or less, whereby the rate of reaction of the sulphuric acid with the lead oxide for the production of lead sulphate and the particle size, homogeneity, consistency, density, plasticity and porosity of the reaction product are controlled, wherein the 5 micron or less tribasic lead sulphate crystals in the discharged battery paste are produced by the mixing and reacting of the sulphric acid with the wetted particulate lead oxide to grow the 5 micron or less tribasic lead sulphate crystals in the reactor mixer prior to the mixture being discharged from the reactor mixer and cured.

2. A method as claimed in claim 1 , in which the mixture is subjected to a ratio of mixing paddles to conveying paddles in the reactor mixer of about 75:25.

3. A method as claimed in claim 1 , in which the discharge product has a temperature in the range of about 68° C. to about 79° C.

4. A method as claimed in claim 3 , in which the controlled retention time in the reactor mixer is in the range of 30 to 45 seconds.

5. A method as claimed in claim 4 , in which the reactor mixer is operated in the range of about 100 to 150 RPM.

6. A method as claimed in claim 5 , in which reinforcing fibres having the characteristics of polymer fibres, polypropylene fibres, modacrylic fibres, glass fibres or cellulose fibres are added with the lead oxide in an amount above 0.15 wt % and up to 0.6 wt % of the lead oxide and uniformly dispersed within the paste, thereby enhancing paste strength and adhesion to grid metal.

7. A method as claimed in claim 6 , in which at least one of carbon powder, activated carbon powder, graphite powder, graphite flakes or graphite spheres is added in an amount above 2 wt % and up to 6 wt % of the lead oxide and uniformly dispersed within the paste.

8. A method as claimed in claim 7 , in which the temperature of the mixture as it passes through the reactor mixer is controlled to produce an exit temperature of the discharge product of about 79° C.

9. A method as claimed in claim 7 , additionally comprising seeding the particulate lead oxide feed with tetrabasic lead sulphate whereby the discharge product contains tetrabasic lead sulphate crystals.

10. A method as claimed in claim 5 , additionally comprising continuously applying the reaction battery paste product to battery grids.

11. A method as claimed in claim 7 , additionally comprising continuously applying the reaction battery paste product to battery grids.

12. A battery paste continuously produced by the method of claim 1 having a maximum particle size less than 1.52 mm and a lead sulphate crystal size in the range of 2 to 5 microns in substantially tribasic form.

13. A battery paste continuously produced by the method as claimed in claim 7 , in which the paste contains at least one of carbon powder, activated carbon powder, graphite powder, graphite flakes or graphite spheres in an amount up to 6 wt % of the lead oxide feed uniformly dispersed within the paste.

14. A battery paste continuously produced by the method as claimed in claim 6 , in which the paste contains polymer fibres, polypropylene fibres, modacrylic fibres, glass fibres or cellulose fibres in an amount up to about 0.6 wt % of the lead oxide feed uniformly dispersed within the paste.

15. A battery paste continuously produced by the method as claimed in claim 13 , in which the paste contains polymer fibres, polypropylene fibres, modacrylic fibres, glass fibres or cellulose fibres in an amount up to about 0.6 wt % of the lead oxide feed uniformly dispersed within the paste.

16. A method as claimed in claim 5 , in which the temperature is controlled to provide a maximum exit temperature of the discharge product of 68-69° C.

17. A method as claimed in claim 5 , in which the temperature is controlled to provide a maximum exit temperature of the discharge product above 70° C. for the formulation and growth of tetrabasic lead sulphate whereby the discharge product contains tetrabasic lead sulphate crystals.

18. A method as claimed in claim 17 , additionally comprising seeding the particulate lead oxide feed with tetrabasic lead sulphate.

19. A method as claimed in claim 17 , in which reinforcing fibres having the characteristics of polymer fibres, polypropylene fibres, modacrylic fibres, glass fibres or cellulose fibres are added with the lead oxide in an amount up to 0.6 wt % of the lead oxide for uniform dispersion of fibres within the paste, thereby enhancing paste strength and adhesion to grid metal.

20. A method as claimed in claim 16 , in which reinforcing fibres having the characteristics of polymer fibres, polypropylene fibres, modacrylic fibres, glass fibres or cellulose fibres are added with the lead oxide in an amount up to 0.6 wt % of the lead oxide and in which at least one of carbon powder, activated carbon powder, graphite powder, graphite flakes or graphite spheres is added in an amount up to 6 wt % of the lead oxide and uniformly dispersed within the paste.

21. A method as claimed in claim 19 , continuously applying the reaction battery paste product to battery grids.

22. A battery paste continuously produced by the method of claim 17 having a maximum particle size less than 1.52 mm and a lead sulphate crystal size in the range of 2 to 5 microns with a controlled amount of tetrabasic lead sulphate.

23. A battery paste continuously produced by the method of claim 19 having a maximum particle size less than 1.52 mm and a lead sulphate crystal size in the range of 2 to 5 microns with a controlled amount of tetrabasic lead sulphate.

24. A battery paste continuously produced by the method of claim 20 having a maximum particle size less than 1.52 mm and a lead sulphate crystal in tribasic form.

25. A lead acid battery having a plurality of battery electrodes pasted by the continuously produced battery paste claimed in claim 22 .

26. A method as claimed in claim 19 , providing a clearance between the elongated reactor mixer and the mixing paddles and the conveying paddles of not more than 1.52 mm whereby feed materials are reduced in size to smaller than 1.52 mm in size.

27. A method as

Assignees

• Vincze Albert M
• Clark Douglas G
• Saleh Victor Nasri
• Dewar Malcolm John
• Fritts Robert W
• Mitek Holdings Inc

Inventors

• Vincze Albert M
• Clark Douglas G
• Saleh Victor Nasri
• Dewar Malcolm John
• Fritts Robert W

Classifications

• H01M10/06

  Lead-acid accumulators (semi-lead accumulators H01M10/20) · CPC title

• H01M4/72

  Grids · CPC title

• H01M4/20 Primary

  of pasted electrodes · CPC title

• Y02P70/54

  Cross-Sectional Technologies · mapped topic

• Y02E60/126

  Cross-Sectional Technologies · mapped topic