阅读说明：本技术 干式电极制造 (Dry electrode manufacture ) 是由 B.韦斯特法尔 于 2019-11-21 设计创作，主要内容包括：本发明涉及一种用于干式制造电极的工艺,所述工艺包括步骤：(1)提供基底,(2)将底漆材料分配到基底上以便在基底上提供底漆层,(3a)将电极材料分配到底漆层上并且(3b)借助压力和/或温度附接所述电极材料以便提供电极材料层。(The invention relates to a process for dry manufacturing an electrode, the process comprising the steps of: (1) providing a substrate, (2) dispensing a primer material onto the substrate so as to provide a primer layer on the substrate, (3a) dispensing an electrode material onto the primer layer and (3b) attaching the electrode material by means of pressure and/or temperature so as to provide a layer of electrode material.)

1. A process for dry manufacturing an electrode, the process comprising the steps of:

(1) a substrate is provided, and the substrate,

(2) dispensing a primer material onto the substrate to provide a primer layer on the substrate,

(3a) dispensing electrode material onto the primer layer and

(3b) the electrode material is attached by means of pressure and/or temperature in order to provide a layer of electrode material.

2. The process of claim 1, wherein the primer material is dispensed as solid particles by electrostatic deposition, preferably by deposition from capacitor plates or by electrostatic spraying.

3. A process according to claim 1 or 2, wherein the primer layer has a thickness of 10nm to 5 μm, preferably 0.05 μm to 1 μm.

4. The process of any one of claims 1 to 3, wherein said primer material is selected from the group consisting of graphite, carbon black, graphene, carbon nanotubes, fullerenes, first binder, and mixtures thereof.

5. The process according to any one of claims 1 to 4, wherein the primer material has an average particle size (D) of 1 to 500nm, preferably 10 to 300nm, more preferably 50 to 200nm₅₀)。

6. The process of any one of claims 1 to 5, wherein the electrode material comprises an active material, a second binder and/or an additive.

7. The process of any one of claims 1 to 6, wherein said electrode material layer has a thickness of 3.0 to 4.0g/cm³Preferably 3.2 to 3.8g/cm³The density of (c).

8. The process of any one of claims 1 to 7, wherein said layer of electrode material has a thickness of 50 to 200 μm.

9. The process according to any one of claims 1 to 8, wherein step (2) further comprises a step (2') of attaching the primer material to a substrate by means of pressure and/or temperature, preferably by rolling with a calender roll or a counter-press roll.

10. A process as claimed in any one of claims 1 to 9, wherein step (3b) comprises attaching the electrode material by means of a roll, preferably a calender roll or a counter-pressure roll.

11. A process according to any one of claims 1 to 10 wherein the substrate comprises first and second surfaces and the primer material is dispensed onto the first and second surfaces simultaneously or sequentially to obtain the first and second primer layers.

12. The process of claim 11, wherein,

(3a) dispensing the electrode material simultaneously onto the first and second primer layers, and

(3b) the electrode material is simultaneously attached to the first and second primer layers.

13. The process of any one of claims 1 to 12, wherein the substrate is an aluminum plate having a thickness of 5 to 30 μm.

14. An electrode obtainable by a process according to any one of claims 1 to 13.

15. An energy storage device comprising an electrode according to claim 14 obtainable by a process according to any one of claims 1 to 13.

Technical Field

The invention relates to a process for dry-type manufacturing of electrodes.

Background

The electrodes of prior art lithium ion batteries are fabricated by wet coating a conductive substrate with a slurry of active material. The preparation of electrodes by dry coating a substrate having a primer layer with an active material has also been studied. It is necessary, however, to coat the substrate with a primer layer to ensure adhesion of the dry-coated active material. The primer layer additionally improves conductivity and electrical resistance properties between the substrate and the active material and further also acts as a protective barrier for the substrate.

The primer layer includes conductive carbon materials, such as graphite and carbon black. The primer layer is prepared in a separate process by wet coating the substrate with a slurry that includes a primer material, a solvent, and a binder. The preparation of substrates with primer layers is known from US 6,627,252B 1.

However, the preparation of a substrate with a primer layer requires additional, separate process steps that are not compatible with the subsequent dry coating step of the active material, thus making it difficult to integrate the two process steps and the primer layer needs to be prepared separately.

The object of the present invention is therefore to provide an improved process for producing electrodes with thin primer layers, which is more efficient in terms of time and cost, is more environmentally friendly, requires less space and fewer process steps and can be integrated into an apparatus for dry coating active materials.

Disclosure of Invention

This technical problem has surprisingly been solved by a process for dry manufacturing an electrode according to the invention, comprising the steps of:

(1) a substrate is provided, and the substrate,

(2) dispensing a primer material onto the substrate to provide a primer layer on the substrate,

(3a) dispensing electrode material onto the primer layer and

(3b) the electrode material is attached by means of pressure and/or temperature in order to provide a layer of electrode material.

It has been surprisingly found that a primer layer can be formed by dispensing a primer material onto a substrate. This new process step does not in particular require first preparing a slurry of primer material, binder and solvent and then applying said slurry on one surface of the substrate board, drying the slurry by heating and then repeating these steps on the second surface of the substrate board.

The process of the present invention allows the steps of applying the primer material and applying the active material to be contained in one process unit. The prior art processes additionally require that the substrate with the primer layer be rolled up for transport to different process equipment and then unrolled. Thus, the process of the present invention is more efficient. Further, the process of the present invention is more environmentally friendly because no potentially harmful solvents are used, such as acetone or N-methyl-2-pyrrolidone (NMP).

In other embodiments, the invention relates to an electrode obtainable by the process of the invention.

In a further embodiment, the invention relates to an energy storage device comprising an electrode obtainable by the process of the invention.

Drawings

Fig. 1 shows an embodiment of the invention. The base plate (10) is moved in the direction of the arrow through different steps. First, a primer material (20) is deposited on the first substrate surface (12) by electrostatic deposition from the capacitor plates (18) to form a first primer layer (22). The substrate is diverted by a diverting roller (30) and a primer material is then deposited on the second substrate surface (14) to form a second primer layer (24). Thereupon the electrode material (40) is simultaneously dispensed onto and attached/fiberized onto the first and second primer layers (22, 24) by two pairs of calender rolls (32). Optionally, the layer of electrode material (40) is also pressed by an additional pair of counter-rotating calender rolls (34).

In fig. 2, a primer material (20) is deposited on the first substrate surface (12) by electrostatic deposition from a capacitor plate (18) and then pressed by a pair of calender rolls (36) to form a first primer layer (22). The substrate is diverted by a diverting roll (30) and a primer material (20) is then deposited on the second substrate surface (14) and then pressed by a pair of calender rolls (36) to form a second primer layer (24). Thereupon the electrode material (40) is simultaneously dispensed onto and attached/fiberized onto the first and second primer layers (22, 24) by two pairs of calender rolls (32). Optionally, the layer of electrode material (40) is also pressed by an additional pair of counter-rotating calender rolls (34).

Fig. 3 illustrates a process including electro-spray deposition. A primer material (20) is simultaneously deposited on the first substrate surface (12) and the second substrate surface (14) by an electrospray deposition device (16) and then optionally pressed by a pair of calender rolls (36) to form first and second primer layers (22, 24). Thereupon the electrode material (40) is simultaneously dispensed onto and attached/fiberized onto the first and second primer layers (22, 24) by two pairs of calender rolls (32). Optionally, the layer of electrode material (40) is also pressed by an additional pair of counter-rotating calender rolls (34).

Detailed Description

The following definitions are important in connection with embodiments of the present invention.

The substrate is a conductive material. Non-limiting examples of substrates are compositions comprising aluminum, copper, nickel and/or titanium. The substrate is preferably composed of aluminum because of its high strength and good conductivity. The substrate may have any shape, but is typically provided in the form of a plate or sheet. The substrate may also be in the form of a batting material or a foamed metal material. The thickness of these plates is about 4 to 30 μm. Flakes much thinner than 4 μm are fragile, difficult to manufacture and have elevated electrical resistance.

The term "comprising" is to be understood as encompassing all the specifically mentioned features as well as optional, additional, unspecified features, whereas the term "consisting of …" encompasses only those specified features. Thus, "comprising" includes the composition described by "consisting of …" as a matter of limitation.

The expression "dry manufacturing an electrode" as used herein relates to a process using dry coating to prepare a primer layer and an electrode material layer. Unlike wet coating, the relevant particles are not first dissolved or dispersed in a solvent, but are directly dispensed. Thus, dry manufacturing involves a process in which no or substantially no solvent is used. Nevertheless, it is understood that even during dry manufacturing of the electrode, the material may contain some residual solvent and/or moisture as impurities or adsorbates from the environment.

The expression "attaching by means of pressure and/or temperature" also includes laminating the substrate with the primer layer with the electrode material, wherein the electrode material is attached mainly by fibrillation of the second adhesive. In the context of the present application, the term "pressure" is understood to include shear forces.

The term "dispensing" and its modified terms as used herein are to be understood in a broad manner to include deposition, casting, coating, laminating, spraying, and like application methods.

The following definitions are in accordance with preferred embodiments of the present invention. The preferred embodiments are preferably used alone or in combination. Furthermore, it should be understood that the following preferred embodiments relate to all aspects of the invention, namely the process for preparing the electrode, the electrode obtainable by such a process and the energy storage device comprising said electrode.

In one embodiment, the primer material is dispensed as solid particles by electrostatic deposition, preferably by deposition from capacitor plates or by electrostatic spraying. In a particularly preferred embodiment, the primer material is dispensed by a corona dispensing device or a triboelectric dispensing device.

Electrostatic deposition is a technique for depositing thin layers of particles by ionization of the particles, for example by corona ionization or by triboelectric friction. The particles are then deposited on the substrate. Unlike, for example, Plasma Enhanced Chemical Vapor Deposition (PECVD), the particles are deposited in solid form. In a preferred embodiment, the deposition is achieved by Electrostatic Spray Deposition (ESD). ESD involves the formation of an electrically charged aerosol of primer material, which is then directed toward the substrate by an electric field.

In a more preferred embodiment, the deposition is from capacitor plates.

In one embodiment, the primer layer has a thickness of 10nm to 5 μm, preferably 0.05 μm to 1 μm. In principle, the primer layer thickness can be as small as one particle layer of the primer particles. In one embodiment, the layer thickness is 10nm to 5 μm, 10nm to 4 μm, 10nm to 3 μm, 10nm to 2 μm, 10nm to 1 μm, 10nm to 0.1 μm. In other embodiments, the layer thickness is 50nm to 5 μm, 0.1 μm to 5 μm, 1 μm to 5 μm. The layer thickness is preferably less than 5 μm. More preferably, the primer layer has a thickness of 10nm to 1 μm. In a particularly preferred embodiment, the primer layer has a thickness of 0.1 to 1 μm. It is to be noted that the thickness of the primer layer refers to the thickness of the obtained electrode.

In one embodiment, the primer material is selected from the group consisting of graphite, carbon black, graphene, carbon nanotubes, fullerenes, a first binder, and mixtures thereof. In a preferred embodiment, the primer material comprises graphite and/or carbon black. In one embodiment, the primer material includes 50 to 100 wt% of a carbon material selected from the group consisting of graphite, carbon black, graphene, carbon nanotubes, fullerenes and mixtures thereof and 0 to 50 wt% of a first binder. In a preferred embodiment, the primer material comprises 70 to 100% by weight of a carbon material selected from the group consisting of graphite, carbon black, graphene, carbon nanotubes, fullerenes and mixtures thereof and 0 to 30% by weight of a first binder. In other embodiments, the primer material does not comprise a binder.

The first binder comprises a polymeric binder. Suitable polymeric binders are Polyethylene (PE), methyl cellulose, fluoroelastomers, poly (vinyl acetate), polyurethane, poly (acrylic acid), poly (methacrylic acid) and mixtures thereof. Non-limiting examples of fluoroelastomers include polyvinylidene fluoride (PVdf), Polytetrafluoroethylene (PTFE), and polyhexafluoropropylene. The polymer may be a homopolymer or a copolymer. Copolymers include statistical copolymers, gradient copolymers, alternating copolymers, block copolymers, and branched copolymers. The first binder preferably comprises polyvinylidene fluoride and/or Polytetrafluoroethylene (PTFE). The first binder particularly preferably comprises polyvinylidene fluoride.

In one embodiment, the primer material has an average particle size (D) of 1 to 500nm, preferably 10 to 300nm, more preferably 50 to 200nm₅₀). In one embodiment, the primer material has a composition of 1 to 400nm,An average particle size (D) of 1 to 300nm, 1 to 200nm, 10 to 500nm, 10 to 400nm, 10 to 300nm, 10 to 200nm, 10 to 100nm, 50 to 500nm, 50 to 400nm, 50 to 300nm, or 50 to 200nm₅₀). The particle size is preferably from 50 to 200 nm. The particle size can be determined by means of laser diffraction, for example ISO 13320:2009, or dynamic light scattering. The particle size of the above primer material refers to the primary particle size. However, the primary particles may also form aggregates having a secondary particle size of not more than 2 μm.

In one embodiment, the electrode material comprises an active material, a second binder and/or an additive. In one embodiment, the electrode material includes 60 to 100 wt% of the active material and 0 to 30 wt% of the second binder and 0 to 10 wt% of the additive. In a preferred embodiment, the electrode material comprises 90 to 100% by weight of the active material and 0 to 10% by weight of the second binder.

Suitable active Materials are disclosed in "Principles and Applications of Lithium Batteries", j.park, first edition, 2012, Wiley-VCH press and "Handbook of Battery Materials", c.daniel, j.beenhard, second edition, 2011, Wiley-VCH press. The active material may be an anode or cathode active material. The active material is preferably a cathode active material.

The anode active material may be classified into an intercalation-based material such as graphite, a transformation reaction-based material, and an alloying reaction-based material.

The cathode active material may be classified into a layered structure compound, spinel and inverse spinel composite materials, olivine composite materials, vanadium composite materials, and mixtures thereof.

Non-limiting examples of layered structure compounds include LCO (LiCoO)₂)、LNO(LiNiO₂)、LMO(LiMnO₂)、LTO(Li_3-xM_xN；M＝Co、Ni or Cu、0.1<x<0.6)、LiFeO₂NMC (Ni-Mn-Co three-component system, e.g. Li [ Ni ]_xMn_xCo_1-2x]O₂、0<x<0.5, preferably LiNi_1/3Mn_1/3Co_1/3O₂(NMC 333) and NCA (Ni-Mn-Al three-component System, e.g. LiNi_0.8Co_0.15Al_0.05). Further, non-limiting examples of NMC include LiNi_8/10Mn_1/10Co_1/10O₂(NMC 811)、LiNi_9/10Mn_0.5/10Co_0.5/10O₂(NMC 9/0.5/0.5) and LiNi_6/10Mn_2/10Co_2/10O₂(NMC 622). In a preferred embodiment, the electrode active material comprises NMC 622.

Non-limiting examples of spinel and inverse spinel composites include LMO (LiMn)₂O₄)、LiTi₂O₄、LiV₂O₄And LiNiVO₄。

Non-limiting examples of olivine composites include LFP (LiFePO)₄) And LiFe_1-xM_xPO₄(0<x<1；M＝Mn、Co、Ni)。

Non-limiting examples of vanadium composites include V₂O₅、V₂O₃、VO₂、V₆O₁₃、V₄O₉、V₃O₇、Ag₂V₄O₁₁、AgVO₃、Li₃V₃O₅、δ-NH₄V₄O₁₀、Mn_0.8V₇O₁₆、LiV₃O₈、Cu_xV₂O₅(0<x<0.3) and Cr_xV₆O₁₃(0<x<0.1)。

In a preferred embodiment, the active material comprises NCA, LCO, LNO, NMC, LTO, LMO or mixtures thereof. A preferred mixture of the above composite materials is a NMC-LMO mixture.

The second binder comprises polyvinylidene fluoride (PVdf), polyhexafluoropropylene, polytetrafluoroethylene (PTFE;) Polyethylene (PE) or mixtures or copolymers thereof. In a preferred embodiment, the second binder is a polyTetrafluoroethylene.

The additive is conductive carbon. In a preferred embodiment, the additive consists of graphite, carbon black, carbon nanotubes, graphene, fullerenes and mixtures thereof. In a preferred embodiment, the additive comprises graphite and/or carbon black. In other embodiments, the electrode material layer has 3.0 to 4.0g/cm³Preferably 3.2 to 3.8g/cm³The density of (c).

In other embodiments, the electrode material layer has a thickness of 50 to 200 μm. In other embodiments, the electrode material layer has a thickness of 20 to 500 μm, 30 to 400 μm, or 40 to 300 μm. In a preferred embodiment, the electrode material layer has a thickness of 70 to 300 μm. In a particularly preferred embodiment, the layer of electrode material has a thickness of 70 to 150 μm. The above thicknesses also apply to the first and second electrode material layers, respectively, if present. It is to be noted that the thickness of the electrode material layer refers to the thickness in the obtained electrode.

In one embodiment, step (2) further comprises the step (2') of attaching the primer material to the substrate by means of pressure and/or temperature, preferably by rolling with a calender roll or a counter-pressure roll.

In one embodiment, step (3b) comprises attaching the electrode material by means of a roll, preferably a calender roll or a counter-roll.

In other embodiments, the substrate comprises first and second surfaces, and the primer material is dispensed onto the first and second surfaces simultaneously or sequentially so as to obtain first and second primer layers. The substrate is typically provided as a sheet, batting or expanded metal having first and second surfaces. The primer layer can be formed simultaneously on the first and second surfaces by the process according to the invention. However, it is also possible to form a first primer layer on the first surface and then sequentially form a second primer layer on the second surface.

The same applies to the formation of the electrode material layer. In one embodiment of the method of the present invention,

(3a) dispensing the electrode material simultaneously onto the first and second primer layers, and

(3b) the electrode material is simultaneously attached to the first and second primer layers.

Thereby forming a first electrode material layer and a second electrode material layer.

In one embodiment, the process comprises the steps of:

(3c) additionally compressing the electrode material layer(s). The additional pressing can be performed by a calender roll or a counter-pressure roll. The additional compaction step may ensure that an optimal electrode material layer density is achieved. 3.2 to 3.8g/cm as described above³Is preferred.

In one embodiment, steps (3a) and (3b) are performed sequentially or simultaneously. Dispensing the electrode material and attaching the electrode material may be performed simultaneously. However, it is also possible to first dispense a layer of electrode material on the primer layer and then attach the electrode material in sequence.

In one embodiment, the process is a continuous process. For efficiency purposes, all steps are preferably performed in a continuous manner.

In one embodiment, the substrate is an aluminum plate having a thickness of 5 to 30 μm. In a preferred embodiment, the substrate is an aluminum plate having a thickness of 8 to 15 μm.

In one embodiment, the electrode is an electrode of a lithium ion battery. In one embodiment, the electrode is a cathode. The electrode is preferably the cathode of a lithium ion battery.