Printing or spray deposition method for preparing a supported flexible electrode and manufacture of a lithium-ion battery

Patent metadata

Field	Value
Publication number	US-2016126554-A1
Application number	US-201414898889-A
Country	US
Kind code	A1
Filing date	Jun 23, 2014
Priority date	Jun 24, 2013
Publication date	May 5, 2016
Grant date	—

Abstract

The present invention relates to a printing or spray deposition method for preparing a supported flexible electrode and to a method for manufacturing a lithium-ion battery.

First claim

1 . Method for preparing a supported flexible electrode having at least one electrode active material, at least one binder and at least one flexible substrate, said method comprising at least the following steps:
i) a step of preparing an electrode ink by dispersing a mixture of solid particles in an aqueous phase, said mixture of solid particles comprising:
at least one electrode active material, in an amount in the range from 70 to 99.5 wt % relative to the total weight of the mixture of solid particles,
at least one binder comprising a lignocellulosic material, in an amount in the range from 0.5 to 30 wt % relative to the total weight of the mixture of solid particles,
said mixture of solid particles representing at least 25 wt % of the total weight of the electrode ink; ii) a step of transferring the electrode ink obtained above in step i) onto at least a portion of one of the faces of a flexible substrate by a printing or spray deposition technique, said flexible substrate being selected from the group consisting of a cellulosic substrate, a polymer film and a polymer membrane optionally reinforced with cellulose; and iii) a drying step to obtain a supported flexible electrode comprising the substrate and an electrode film deposited on at least a portion of one of the faces of said flexible substrate.

2 . Method according to claim 1 , wherein the lignocellulosic material is selected from the group consisting of cellulose fibres, refined cellulose fibres, cellulose microfibrils, cellulose nanofibrils and lignin.

3 . Method according to claim 1 , wherein the binder comprising a lignocellulosic material represents from 0.5 to 1.5 wt % relative to the total weight of the mixture of solid particles.

4 . Method according to claim 1 , wherein a fibre anti-flocculant is incorporated in the aqueous suspension in step i).

5 . Method according to claim 4 , wherein the anti-flocculant is selected from carboxymethylcellulose (CMC), starch, modified starch and a mixture thereof.

6 . Method according to claim 4 , wherein the fibre anti-flocculant represents from 0.5 to 2.5 wt % relative to the total weight of the mixture of solid particles.

7 . Method according to claim, wherein an agent generating electron conductivity is incorporated in the aqueous suspension in step i).

8 . Method according to claim 7 , wherein the agent generating electron conductivity is selected from the group consisting of carbon black, carbon SP, acetylene black, carbon fibres and nanofibres, carbon nanotubes, metal particles and fibres and a mixture thereof.

9 . Method according to claim 7 , wherein the agent generating electron conductivity represents from 25 to 35 wt % relative to the total weight of the mixture of solid particles.

10 . Method according claim 1 , wherein the concentration by weight of the mixture of solid particles in the electrode ink at the end of step i) varies from 28 to 42%.

11 . Method according to claim 1 , wherein the printing technique used is selected from the group consisting of screen printing, flexography and gravure printing.

12 . Method according to claim 4 to 11 , wherein dispersion of the mixture of solid particles in an aqueous phase in step i) is carried out according to the following substeps:
i-1) the anti-flocculant and the aqueous phase are mixed and dispersed using a mechanical blade dispersing machine, for a time ranging from 2 to 10 min at a speed ranging from 450 to 550 rev/min,
i-2) the binder comprising a lignocellulosic material is added to the mixture obtained above in step i-1), then the resultant mixture is dispersed for a time ranging from 5 to 20 min at a speed ranging from 450 to 550 rev/min,
i-3) the electrode active material and optionally the agent generating electron conductivity are added to the mixture obtained above in step i-2), then the resultant mixture is dispersed for a time ranging from 5 to 20 min at a speed ranging from 450 to 550 rev/min,
i-4) the mixture thus obtained in step i-3) is stirred mechanically using a mechanical blade dispersing machine for a time ranging from 10 to 25 min, at a speed ranging from 2500 to 3500 rev/min.

13 . Method according to claim 12 , wherein when an anode active material is used in step i-3), the mixture obtained in step i-3) is homogenized according to an additional substep in a three-roller mill for a time in the range from 5 to 10 minutes before carrying out step i-4).

14 . Method according to claim 1 , wherein the electrode film deposited on at least a portion of one of the faces of said substrate has a thickness ranging from 30 to 100 μm.

15 . Method according to claim 1 , wherein said method further comprises a step iv) of calendering the supported flexible electrode as obtained according to step iii).

16 . Method according to claim 1 , wherein the electrode active material used in step i) and making it possible to obtain a supported flexible positive electrode, is selected from Li x Mn y O 4 (0<x<2, 0<y<2 and x+y=3), LiCoO 2 , LiMPO 4 , (M=Fe, Mn, Co, Ni), LiAl x Co y Ni z O 2 (0<x<1, 0<y<1, 0<z<1 and x+y+z=1) and LiNi (1-y) Co y O 2 (0≦y≦1).

17 . Method according to claim 1 , wherein the electrode active material used in step i) and making it possible to obtain a supported flexible negative electrode is selected from: graphite, hard carbon, soft carbon and the metal alloys Li y M (1<y<5 and M=Mn, Sn, Pb, Si, In, Ti).

18 . Method for manufacturing a lithium-ion battery comprising:
a supported flexible positive electrode comprising a flexible substrate S1 and a cathode film F1 deposited on at least a portion of one of the faces of said flexible substrate S1, and a supported flexible negative electrode comprising a flexible substrate S2 and an anode film F2 deposited on at least a portion of one of the faces of said flexible substrate S2, a gel electrolyte or a liquid electrolyte placed between said electrodes, with said method comprising at least the following steps: a) a step of preparing a supported flexible positive electrode according to steps i), ii), iii) and optionally step iv) of the method as defined according to claim 1 , b) a step of preparing a supported flexible negative electrode according to steps i), ii), iii) and optionally step iv) of the method as defined according to claim 1 , c) a step of assembling the electrodes as obtained above in steps a) and b), so that said flexible substrates S1 and S2 are placed face to face in said battery, thus forming a separator S1-S2 between the cathode film F1 and the anode film F2, and one or other of the following steps: d-1) a step of impregnating the electrodes as assembled above in step c) with a liquid electrolyte, or d-2) a step of encapsulating the gel electrolyte in each of the flexible substrates S1 and S2, said encapsulation step taking place before steps a) and b) of preparing the electrodes.

19 . Method for manufacturing a lithium-ion battery comprising:
a supported flexible positive electrode comprising a flexible substrate S1 and a cathode film F1 deposited on at least a portion of one of the faces of said flexible substrate S1, and a supported flexible negative electrode comprising said flexible substrate S1 and an anode film F2 deposited on at least a portion of the other face of said flexible substrate S1, a gel electrolyte or a liquid electrolyte placed between said electrodes, with said method comprising at least the following steps: a) a step of preparing a supported flexible positive electrode according to steps i), ii), iii) and optionally step

Assignees

• Inst Polytechnique Grenoble
• Centre Nat Rech Scient

Inventors

• Beneventi Davide
• Chaussy Didier
• El Baradai Oussama
• Jabbour Lara
• Bongiovanni Roberta

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/0402

  Methods of deposition of the material · CPC title