# US 2004/0072074 A1 · Electrode for a battery

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- Number: US 2004/0072074 A1
- Document ID: US20040072074A1
- Status: Published application
- Kind: A1
- Application number: 10/466,861
- Filed: 2003-09-05
- Published: 2004-04-15
- Earliest claimed: 2001-01-19
- Assignees: Atraverda Limited
- Inventors: Thomas John Partington
- Web page: https://patentgrep.com/patent/US20040072074A1

## CPC

- H01M 4/624: {Electric conductive fillers}
- H01M 4/0433: {Molding}
- H01M 4/16: Processes of manufacture
- H01M 4/20: of pasted electrodes
- H01M 4/48: of inorganic oxides or hydroxides
- H01M 4/68: for use in lead-acid accumulators
- H01M 4/82: Multi-step processes for manufacturing carriers for lead-acid accumulators
- H01M 10/4285: {Testing apparatus}
- H01M 4/668: {Composites of electroconductive material and synthetic resins}
- H01M 4/78: Shapes other than plane or cylindrical, e.g. helical
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An electrode for a bipolar cell or battery comprises a plate like body made of hardened resin containing particles of titanium suboxide or other electrically conductive particulate arranged to form electrical paths. A method of testing the body for porosity is also disclosed.

## Claims

### Claim 1

An electrode comprising a shaped substantially pore-free body of hardened resin and having electrical paths defined by contacting conductive particles.

### Claim 2 (depends on 1)

An electrode according to claim 1, wherein the conductive particles are oxides of a transition metal or of doped tin oxide.

### Claim 3 (depends on 1)

An electrode according to claim 1, wherein the conductive particles are titanium suboxide of the formula Tin02n−1 where n is 4 or greater.

### Claim 4 (depends on 3)

An electrode according to claim 3, wherein the titanium suboxide comprises Ti4O7 and/or Ti5O9.

### Claim 5

An electrode according to any preceding claim, wherein the particles have a mean particle size in the region of about 50 to about 300 micron.

### Claim 6

An electrode according to any preceding claim, wherein the particles have a particle size distribution with a standard deviation of less than the mean particle size.

### Claim 7

An electrode according to any one of the preceding claims, wherein there is a bimodal distribution of substantially uniform large particles and a proportion of smaller particles dimensioned to fit in the interstices between the large particles

### Claim 8 (depends on 1, 2, 3, 4, 5, 6)

An electrode according to any one of claims 1 to 6, wherein there is a polymodal distribution of a range of particle sizes ranging from large particles to successively smaller particles dimensioned to fit in the interstices between larger particles.

### Claim 9

An electrode according to any one of the preceding claims, wherein the particles have a particle size distribution with a variation of less than 50% of the mean particle size.

### Claim 10

An electrode according to any one of the preceding claims, wherein there is less than 50% (wt.) resin and hardener.

### Claim 11

An electrode according to any preceding claim, wherein the resin is resistant to battery acid electrolyte.

### Claim 12

An electrode according to any preceding claim, wherein the resin is a thermoset resin.

### Claim 13 (depends on 12)

An electrode according to claim 12, wherein the thermoset resin is an epoxy.

### Claim 14

An electrode according to any preceding claim, including high aspect and/or low aspect particles of the titanium suboxide to increase connectivity.

### Claim 15

An electrode according to any preceding claim, having an overall electrical conductivity greater than 0.5 S.cm−1.

### Claim 16 (depends on 15)

An electrode according to claim 15, having an orthogonal conductivity greater than 1.S.cm−1.

### Claim 17 (depends on 15, 16)

An electrode according to claim 15 or 16, having a leakage current of less than 1 A/m2.

### Claim 18

An electrode according to any preceding claim, in the form of a plate which is flat or has curvature.

### Claim 19

An electrode according to any preceding claim, which has a metallic layer applied to a surface thereof.

### Claim 20 (depends on 19)

An electrode according to claim 19, where the metallic layer has areas of differing corrosion rates.

### Claim 21 (depends on 19)

An electrode according to claim 19, where the metallic layer is replaced by a lead dioxide or doped tin dioxide layer.

### Claim 22 (depends on 18)

An electrode according to claim 18, comprising a plate having a flange whereby the plate electrode in a cell may be sealed to a casing.

### Claim 23 (depends on 22)

An electrode according to claim 22, wherein the plate electrode is sealed in a casing which is secured to the flange by adhesive or welding.

### Claim 24 (depends on 22, 23)

An electrode according to claim 22 or 23, wherein the flange is free of the particles of titanium suboxide.

### Claim 25 (depends on 22, 23, 24)

An electrode according to any one of claims 22, 23 or 24, wherein the plate is received in a slot in the casing therefor.

### Claim 26

An electrode according to any preceding claim, comprising a plate having a metal grid or mesh or sheet in the body thereof.

### Claim 27 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)

An electrode according to any of claims 1 to 26, comprising a plate having cooling channels in the body thereof.

### Claim 28

An electrode according to any preceding claim, wherein the surface of the electrode has surface deformation for receiving and retaining active paste material.

### Claim 29 (depends on 28)

An electrode according to claim 28, wherein the deformations are moulded in the surface.

### Claim 30 (depends on 28, 29)

An electrode according to claim 28 or 29, wherein the deformations are formed in the surface after the electrode has been moulded.

### Claim 31 (depends on 28, 29, 30)

An electrode according to any one of claims 28 to 30, wherein the deformations are dimensioned and shaped to receive different thicknesses of paste in different areas.

### Claim 32

A method of making an electrode, the method comprising mixing an unhardened resin, a hardener therefor, and conductive particles and pouring the mix into a mould therefor and moulding the mix to form a shaped substantially pore-free body electrode having electrical paths defined by the contacting conductive particles.

### Claim 33 (depends on 32)

A method according to claim 32, wherein up to 50% by weight of the mix comprises the resin and hardener.

### Claim 34 (depends on 32, 33)

A method according to claim 32 or claim 33, wherein the mix includes a bimodal distribution of substantially uniform large particles and a proportion of smaller particles dimensioned to fit in the interstices between the large particles.

### Claim 35 (depends on 32, 33)

A method according to claim 32 or claim 33, wherein the mix includes a polymodal distribution of a range of particle sizes ranging from large particles to successively smaller particles dimensioned to fit in the interstices between larger particles.

### Claim 36 (depends on 32, 33, 34, 35)

A method according to any one of claims 32 to 35, wherein the particles have a particle size distribution with a standard deviation of less than the mean particle size prior to moulding.

### Claim 37 (depends on 32, 33, 34, 35, 36)

A method according to any one of claims 32 to 36, wherein the particles have a particle size distribution with a variation of less than 50% of the mean particle size prior to moulding.

### Claim 38 (depends on 32, 33, 34, 35, 36, 37)

A method according to any one of claims 32 to 37, wherein the conductive particles of an oxide of a transition metal.

### Claim 39 (depends on 32, 33, 34, 35, 36, 37, 38, 39)

A method according to any one of claims 32 to 39, wherein the conductive particles are of titanium suboxide of the formula Tin02n−1 where n is 4 or greater.

### Claim 40 (depends on 30)

A method according to claim 30, wherein the titanium suboxide comprises Ti4O7 and/or Ti5O9.

### Claim 41 (depends on 39, 40)

A method according to claim 39 or 40, wherein the particles of the titanium suboxide are first contacted with a gas for a period to extend the conductivity thereof.

### Claim 42 (depends on 41)

A method according to claim 41, wherein the gas is helium or hydrogen.

### Claim 43 (depends on 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)

A method according to any of claims 32 to 42, wherein the resin is a thermoset resin.

### Claim 44 (depends on 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)

A method according to any of claims 32 to 43, wherein the resin has a viscosity of less than about 50 Pa.s at 25° C.

### Claim 45 (depends on 43, 44)

A method according to claim 43 or claim 44, wherein the resin is epoxy resin.

### Claim 46 (depends on 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)

A method according to any of claims 32 to 44, wherein the unhardened resin and hardener are mixed, and the conductive particles are added to form a dough which is then added to a preheated mould.

### Claim 47 (depends on 46)

A method according to claim 46, wherein the resin, hardener and particles are first formed into sheet moulding compound which is added to the mould.

### Claim 48 (depends on 47)

A method according to claim 47, including the step of applying foils of metal to one or both surfaces of the sheet moulding compound.

### Claim 49 (depends on 47, 48)

A method according to claim 47 or 48, including the step of placing the mould in a heated press and applying pressure.

### Claim 50 (depends on 49)

A method according to claim 49, wherein the pressure exceeds 2000 Pa.

### Claim 51 (depends on 49, 50)

A method according to claim 49 or 50, wherein the mould is heated to more than 35° C.

### Claim 52 (depends on 51)

A method according to claim 51, wherein the mould is heated to more than 70° C.

### Claim 53 (depends on 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)

A method according to any of claims 33 to 52, including the step of removing the shaped article from the mould and cleaning the surfaces.

### Claim 54 (depends on 53)

A method according to claim 53, wherein the method of cleaning includes grit blasting.

### Claim 55 (depends on 53)

A method according to claim 53, wherein the method of cleaning includes corona discharge treatment.

### Claim 56 (depends on 53)

A method according to claim 53, wherein the method of cleaning includes application of plasmas.

### Claim 57 (depends on 53)

A method according to claim 53, wherein the method of cleaning includes chemical etching.

### Claim 58 (depends on 53)

A method according to claim 53, wherein the method of cleaning includes solvent degreasing.

### Claim 59 (depends on 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58)

A method according to any of claims 32 to 58, wherein excess resin is ejected from the mould during pressing.

### Claim 60 (depends on 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59)

A method according to any of claims 32 to 59, including subsequently applying a battery paste to the electrode.

### Claim 61 (depends on 60)

A method according to claim 60, including the step of applying a thin layer of metal to the electrode before the paste is applied.

### Claim 62 (depends on 61)

A method according to claim 61, including the step of pressing a metal foil on to the surface of the electrode whilst in the moulding press while the resin is curing.

### Claim 63 (depends on 62)

A method according to claim 62, wherein the metal foil is up to 200 micron thick.

### Claim 64 (depends on 61)

A method according to claim 61, including applying the metal layer by electroplating and optionally adding dispersoids to the plating solution.

### Claim 65 (depends on 63)

A method according to claim 63, including treating the surface of the metal layer with a corona discharge or plasma.

### Claim 66 (depends on 59, 60, 61, 62, 63, 64)

A method according to any of claims 59 to 64, including adding a coupling and/or wetting agent to the paste.

### Claim 67 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65)

A battery including an electrode according to any of claims 1 to 31 or when made by a method according to any of claims 32 to 65.

### Claim 68 (depends on 67)

A battery according to claim 67, comprising a plurality of electrodes and an acid electrolyte.

### Claim 69

A method of testing an electrode to confirm the absence of invisible micropores through the electrode before pasting, the method comprising placing a test electrode in a simulated battery and measuring the flow of current over time.

### Claim 70 (depends on 69)

A method according to claim 69, including using an external power supply to adjust the electrical potential across the electrodes.

### Claim 71 (depends on 69, 70)

An electrode having a current leakage of less than 1 A/m2 for 28 days when tested by a method according to claim 69 or 70.