DE102016215337A1 - METHOD FOR PRODUCING AN ELECTRODE FOR AN ELECTROCHEMICAL ENERGY STORAGE CELL, ELECTROCHEMICAL ENERGY STORAGE CELL AND VEHICLE - Google Patents

Abstract

The invention relates to a method for producing an electrode for an electrochemical energy storage cell, in particular lithium-ion cell, an electrochemical energy storage cell and a vehicle. In the method according to the invention, a, in particular plastically deformable, composite is produced, which comprises the following components: carboxymethylcellulose, styrene-butadiene rubber, polytetrafluoroethylene, active material and carrier liquid, wherein the proportion of the carrier liquid in the composite is at most 20% by weight. The composite is applied to a metallic collector layer and dried by removing the carrier liquid.

Description

The invention relates to a method for producing an electrode for an electrochemical energy storage cell, in particular a lithium-ion cell, an electrochemical energy storage cell and a vehicle having an electrochemical energy storage cell.

The storage of electrical energy plays a central role, for example, in smartphones, power tool applications, laptops or in electromobility. In order to make the corresponding means of communication or vehicles more efficient and efficient, energy stores with high energy density or specific energy are required. A promising approach is lithium-ion batteries, which have a relatively high energy density and specific energy and reliability.

Such an electrochemical energy storage device essentially comprises two electrodes, which are separated by a separator, and an electrolyte for transporting lithium ions between the electrodes. In processes for producing the electrodes, collector films are coated with so-called slurries (coating composition) in which an active material, carbon black and electrode binder are dispersed in a solvent, and then dried in a complicated process. Depending on the nature of the binder and carrier solvent, this may be, for example, dissolved (e.g., PVdF in NMP) or suspended (e.g., SBR in water).

It is an object of the invention to specify a method for the simple and reliable production of an electrode for electrochemical energy storage cells, a corresponding electrochemical energy storage cell and a vehicle having such electrochemical energy storage cells.

This object is achieved by the method for producing an electrode for an electrochemical energy storage cell and the electrochemical energy storage cell according to the independent claims and a vehicle having such electrochemical energy storage cells.

A method for producing an electrode for an electrochemical energy storage cell, in particular a lithium-ion cell, according to one aspect of the invention comprises the following steps: producing a, in particular plastically deformable, composite comprising the following components: carboxymethyl cellulose (CMC), styrene-butadiene Rubber (SBR), polytetrafluoroethylene (PTFE), active material and carrier liquid, the proportion of carrier liquid in the composite, ie based on the composite coating composition, at least 0.5% by weight and at most 20% by weight, applying the composite to a metallic collector layer and removing the carrier liquid from the composite.

An electrochemical energy storage cell, in particular a lithium-ion cell, according to another aspect of the invention comprises a metallic collector layer and a dry composite applied to the metallic collector layer, which is obtainable by mixing carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR ), Polytetrafluoroethylene (PTFE), active material and carrier liquid, wherein the proportion of the carrier liquid to the composite is at most 20% by weight, and removing the carrier liquid from the composite after the composite has been applied to the metallic collector layer.

A vehicle according to the invention, in particular a motor vehicle, has a large number of electrochemical energy storage cells according to the invention, in particular lithium-ion cells.

However, the use of electrodes or energy storage cells according to the invention is not restricted to electromobility. The invention therefore also relates to a mobile device, in particular for telecommunications, and / or a stationary storage for electrical energy with one or more such electrodes and / or energy storage cells.

One aspect of the invention is based on the batch, carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR) and polytetrafluoroethylene (PTFE), which act as binders and are also referred to below as "binder components", with addition and / or in the presence of a small amount of carrier liquid with an active material, which preferably contains Leitruß, to mix into a composite, wherein the proportion of the carrier liquid in the total mass of the composite is not more than 20% by weight. Due to the small amount of carrier liquid in comparison to conventional methods of the prior art, the carrier liquid is to some extent an aid for uniform distribution of the materials in the composite. The wet composite is applied to a metallic collector layer and then dried by removing the carrier liquid (e.g., by heat and / or vacuum).

For example, one or more of the binders, such as SBR and / or PTFE, may already be suspended in carrier liquid or dissolved (eg, CMC) before being mixed with the remainder of the recipe components. Alternatively or additionally, at least one binder, such as CMC, is present in the dry state and is first dissolved or dissolved in carrier liquid before it is mixed with the rest Components is mixed. However, it is also possible to add the carrier liquid only after all other components have been present in dry form in a mixer and preferably mixed as homogeneously as possible.

By mixing said binder components with the active material in the presence of a comparatively small amount of carrier liquid is - compared with dry mixtures or known suspensions - easily homogenizable or homogeneous and, especially at relatively low temperatures, plastically deformable and thus easy to handle composite obtained , which can be applied to the metallic collector layer in a simple and safe manner. Since comparatively little carrier liquid is used in the production process, the time and energy required for removing the carrier liquid after the application of the composite to the collector layer is significantly reduced in comparison to known suspensions. Not least due to the significantly solvent-reduced mixing of binders, Leitruß and active material possible segregation or sediment formation is virtually prevented in conventional suspensions, whereby quality and life of the electrodes or the cell itself are advantageously increased.

Overall, the invention enables a simple, cost-reduced, environmentally friendly and safe or more reliable production of electrodes for electrochemical energy storage cells.

In the context of the present invention, the terms "lithium-ion battery" and "lithium-ion secondary battery" are used interchangeably. The terms also include the terms "lithium battery", "lithium ion secondary battery" and "lithium ion cell" and all lithium alloy batteries. Thus, the term "lithium ion battery" is used as a generic term for the conventional terms used in the prior art. In particular, a "battery" in the context of the present invention also includes a single "electrochemical cell".

Preferably, at least one of the binders, i. CMC, SBR and / or PTFE, and / or the active material, optionally including electrical Leitadditive, dissolved in powder or in carrier liquid or before or when they are mixed together to form the composite. For example, CMC can be thickened with water. Alternatively or additionally, CMC or PTFE can be applied as a suspension. By "powdery" or "powder" is meant a substantially dry granular solid of a plurality of particles. Depending on the size, size distribution, agglomeration and / or shape of the particles, a powder may optionally also be a powder or granules.

The carrier liquid preferably has at least one aprotic-polar solvent, in particular acetone, N-methyl-2-pyrrolidone (NMP) or N-ethyl-2-pyrrolidone (NEP), or a protic-polar solvent, in particular alcohol or water. The resulting composite can be processed particularly easily and safely into a homogeneous coating composition, applied to the collector layer and allowed to dry.

It is further preferred that a dispersant is added as a further component in the manufacture of the composite. As a result, a particularly good homogeneous mixing of the other components is promoted and stabilized. Polyvinylpyrrolidone (PVP) is preferably used as the dispersant. Thus, the mixing process can be realized faster and with less waste.

The proportion of the carrier liquid in the composite is preferably at most 15% by weight, particularly preferably at most 10% by weight. This results in a composite with particularly high and consistent homogeneity, which nevertheless can be easily and safely processed, applied to the collector layer and allowed to dry.

The proportion of the carrier fluid in the composite is preferably at least 1% by weight, more preferably at least 2% by weight, in particular at least 4% by weight.

Preferably, the composite is made by mixing the components at a temperature which is above the glass transition temperature of one or more of the binders, ie, CMC, SBR, and PTFE. The glass transition temperature, which is also referred to as the softening temperature, is the temperature above which an amorphous or partially crystalline solid, eg pulverulent CMC or SBR, changes from a hard-elastic state to a soft-elastic or liquid state and a rubber-like to viscous melt is obtained , Depending on the type of binder used, typical glass transition or softening temperatures are between about 60 and 130 ° C. Preferably, below the glass or softening temperature of a binder or of the binder mixture, the Vicat softening temperature (VST, Vicat softening temperature) is VST / A50, VST / A120, VST / B50 or VST / B120 DIN EN ISO 306 to understand. By the existing carrier liquid, the glass transition temperature or softening temperature of the binder or the binder can be reduced.

In a preferred embodiment, the mixing of the components is carried out at a temperature which is between the glass transition temperature and the melting temperature of one or more of the binders, ie CMC, SBR and PTFE. Above the melting temperature, crystalline or partially crystalline components change from the solid to the liquid state of aggregation. As a result, on the one hand a plastic deformability of the binder or of the binder and thus of the composite is ensured, and on the other hand, at least partial liquefaction of the binder or the binder, which would make a more complex curing process necessary avoided. In particular, the binder or the binders are converted into a, preferably viscous, melt, which can be processed particularly easily and safely (further). Due to the carrier liquid present in small amounts, such a viscous melt can be obtained at lower temperatures than when mixing without carrier liquid. The carrier liquid thus also has the function of a plasticizer or plasticizer in this case.

Preferably, at least one of the binders is present at the beginning of the process as a solid or dissolved in carrier liquid or suspended and is softened by heating to a temperature above the glass transition temperature, in particular plastically deformable and correspondingly easy to process. As a result, the handling, in particular the dosage, of the binder mixture or of the at least one component of the binder mixture becomes particularly simple.

The heating of the components, in particular of the at least one binder, can take place at different times or in different time periods, for example even before mixing the at least one binder with the active material and / or the carrier liquid after an initial mixing of the not yet softened binder the active material and / or the carrier liquid, or during the mixing of the at least one binder with the active material and / or the carrier liquid.

Due to the presence of relatively small amounts of carrier liquid in combination with a heating above the respective softening temperature, the resulting composite can be processed particularly easily and safely or applied to the metallic collector layer. The use of the electrodes obtained in this way significantly increases the lifetime of electrochemical energy storage cells.

The temperature between the glass transition temperature and the melting temperature depends on the molecular parameters of the at least one binder, in particular on the polymer used, its side groups and / or its chain length. Preferably, the temperature or at least the temperature range between the glass transition temperature and the melting temperature can be determined by means of differential scanning calorimetry on the at least one binder. This ensures that the at least one binder is heated on reaching the determined temperature in such a way that the first solid, preferably pulverulent, at least one binder has been converted into a melt, which is a simple and safe mixing with the active material and a simple and safe application of the composite allowed on the metallic collector layer. This advantageous effect is further enhanced by the presence of small amounts of carrier liquid, since a lower glass transition or softening temperature or a correspondingly lower temperature range for glass transition or softening is generally obtained by the carrier liquid, i. the carrier liquid has the function of a plasticizer (plasticizer).

In a further preferred embodiment, the binder components are mixed in the presence of the carrier liquid with the active material by kneading, preferably in a kneader or extruder. Preferably, the kneader or extruder is heatable. In particular, the kneader or extruder is heated during the mixing process. Preferably, the composite is kneaded such that caused shear forces substantially disappear or at least remain small, preferably at a shear gradient of below 10 s ^-1 , more preferably below 1 s ^-1 , in particular at substantially 0.1 s ^-1 . As a result, the binder components are mixed particularly gently with the active material, so that a homogeneous composite is obtained in which the polymers or molecular chains contained therein are not significantly impaired by the mixing. The mixing container is preferably designed double-walled, so that it can be cooled and heated during the mixing process in order to keep the processing temperature in the range of the glass transition temperature as constant as possible.

Advantageously, at least two of the binder components may also be premixed prior to mixing with the active material and / or conductive carbon black, in particular by kneading, preferably in a pre-kneader or pre-extruder. The premixed binder component mixture can then be mixed particularly well with the active material and optionally with at least one further binder component, so that the composite produced is particularly homogeneous.

During dosing or mixing carrier liquid can be added or present. Preferably, the mixer or kneader can be heated in order to bring or to hold the components to be mixed or the composite at the respectively required temperature. In order to prevent carrier liquid from escaping during the process, the metering and / or mixing is preferably carried out in a closed container.

The temperature in the kneading region of the kneader or extruder, if appropriate also of the pre-kneader or extruder, is preferably adjustable such that the binder components to be mixed and / or the active material can be heated to a temperature above the glass transition temperature or softening temperature. Preferably, the kneader or extruder, if appropriate also the pre-kneader or extruder, is double-walled, so that the set temperature in the kneading region remains substantially constant even when one or more binder components and / or the active material are refilled. This reliably ensures that a homogeneous and soft, in particular plastically deformable and processable composite is produced.

In a further preferred embodiment, the application of the composite to the metallic collector layer takes place by lamination. In this thermal joining process, the composite and the collector layer, preferably without auxiliary materials, materially and interfacially connected. As a result, the composite, in particular the binder mixture of CMC, SBR and PTFE contained in the composite, adheres particularly reliably and permanently to the metallic collector layer.

In a preferred embodiment, prior to lamination, the coating composition, i. the composite, onto a carrier sheet, e.g. of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), applied, freed from the carrier liquid and laminated to the collector layer. The plastic carrier film can then be removed. With sufficient mechanical stability of the composite, alternatively, a so-called free-standing film can be produced, which can then be laminated to the collector layer without a carrier film.

By laminating on the metallic collector layer, electrodes with composite layers of more than 100 μm thickness can preferably be produced, wherein the composite reliably adheres to the metallic collector layer even under mechanical loads.

In another preferred embodiment, the negative electrode active material contains a lithium intercalating material, i. a material that can store lithium or lithium ions. The lithium intercalating material preferably comprises carbon, in particular graphite, and / or silicon. As a result, it is particularly easy to produce porous, in particular negative, electrodes.

In a further preferred embodiment, the active material additionally contains an electrically conductive material, in particular so-called conductive carbon black, conductive graphite, graphene, carbon nanotube (CNT) or a mixture of two or more of these materials. As a result, the electrical conductivity of the composite is advantageously increased, so that electrons released during the oxidation are transported particularly well from the reaction site on the surface of the electrode to the metallic collector foil or for the reduction of electrons from the metallic collector foil to the reaction site on the surface of the electrode can be. The use of carbon nanotubes in the composite electrode increases the electrical conductivity of the composite while at the same time reducing the volume fraction or proportion by weight of the carbon nanotubes in comparison with carbon black and / or graphite.

In a further preferred embodiment, the proportion of binder components in the composite is between 1 and 15% by weight. On the one hand good adhesion properties, in particular on the metallic collector foil, for example a copper layer, and / or good mechanical film properties, in particular high flexibility, of the composite (composite electrode) are achieved, and on the other hand it is avoided that too high a fraction of the Binder mixture on the composite reduces the electrical conductivity of the electrode produced.

In a further preferred embodiment, the proportion of carboxymethylcellulose (CMC) in the entirety of the binder components is between 1 and 35% by weight and / or the proportion of styrene-butadiene rubber (SBR) in the entirety of the binder components is between 1 and 70% by weight and / or the proportion of polytetrafluoroethylene (PTFE) in the total of the binder components is between 1 and 50% by weight. As a result, the composite, in particular with regard to its adhesion properties and / or its mechanical properties, for example with regard to pressing or cutting a so-called mother roll, can be tuned particularly well. Preferably, the processing, in particular the kneading, the binder components and / or the mixing of the binder components with the active material, can also be advantageously influenced thereby.

Preferably, by these mixing ratios of CMC, SBR and PTFE, a composite can be produced in which the combination of CMC and SBR causes a strong adhesion between the composite and the metallic collector layer. The advantageous interaction of the binder mixture of CMC and SBR leads to a homogeneous distribution of the composite on the collector layer. At the same time, the composite remains mechanically highly loadable due to the proportion of PTFE, without embrittlement and / or flaking off of the composite occurring in the further processing process, in particular during cutting, punching and / or winding, and / or during operation of the electrode. In particular, the ductile properties of PTFE result in a homogeneous, uniformly flat and smooth surface of the electrode produced, whereby the discharge of micro-, submicron- or nanoparticles from the electrode, in particular during their production, further processing or operation, is avoided. At the same time, a homogeneous surface of the electrode produced leads to a more uniform pressure distribution in the electrochemical energy store and thus increased reliability or service life of the cell itself. In addition, PTFE advantageously influences the wetting of the electrode produced by fluorinated organic electrolytes and polymer electrolytes. Overall, the manufacturing method and / or the operation of the electrode on the one hand particularly reliable and simple and on the other hand advantageously increases the life of the electrodes produced.

In particular, due to the mentioned mixing ratios of CMC, SBR and PTFE, any disadvantages of using binders or binder mixtures from some of these components, e.g. PTFE as a binder or CMC / SBR as a binder mixture, avoided or at least significantly reduced.

In a further preferred embodiment, the collector layer is heated before or during the application of the composite to a temperature which is above the glass transition temperature of at least one of the binder components in the presence of the carrier liquid. In particular, the collector layer is heated to a temperature which is between the glass transition temperature and the melting temperature of the at least one binder component in the presence of the carrier liquid. This reliably prevents the composite, when applied to the metallic collector layer, from cooling off by the release of heat to the metallic collector layer, before the composite reliably adheres to the metallic collector layer, in particular by lamination.

In a further preferred embodiment, the collector layer is heated by passing it over at least one heated roller roller whose temperature is above the glass transition temperature of the at least one binder component in the presence of the carrier liquid. As a result, the collector layer is heated particularly reliably. Preferably, the at least one heated roller is also adapted to bring the collector layer to the composite, in particular to an outlet opening of a kneader or extruder, from which the mixed composite emerges, for example an outlet nozzle, and preferably for further processing, in particular for cutting, punching and / or winding, transporting away. As a result, the manufacturing process is kept very simple.

In a further preferred embodiment, the composite is applied to the metallic collector layer by means of a template, by means of which the composite is brought into a predetermined shape and / or layer thickness, and / or by applying a pressure, in particular a contact pressure, by pressing the composite onto the collector layer applied. As a result, the electrode to be produced can be impressed on a given shape and / or thickness in a particularly simple manner. In addition, the composite adheres to the metallic collector layer under pressure (optionally by heat input) particularly reliable and durable.

In a further preferred embodiment, the collector foil is etched and / or roughened before the application of the composite and / or coated, in particular with a bonding agent. By etching, the surface of the collector foil is activated and / or roughened and thereby advantageously increases the adhesion forces between the composite and the collector foil. Etching cleans and activates the surface of the collector; this improves in particular the adhesion between electrode and collector foil. Likewise, a coating, in particular with a bonding agent, increases the adhesion between the composite and the collector film particularly reliably. If an electrically conductive additive is added to the adhesion promoter, the contact resistance between electrode and collector can also be reduced. The layer thickness, in particular of the adhesion promoter, is preferably a fraction of the layer thickness of the collector layer, preferably 40%, particularly preferably 20%, in particular substantially 5-15%, of the layer thickness of the collector layer.

Other features, advantages and applications of the invention will become apparent from the following description taken in conjunction with a figure. It shows:

1 an example of an apparatus for producing a composite and applying the Composites on a collector foil in a highly schematic representation.

1 shows an example of a device 1 with a mixer 2 for making a composite 8th , a first roller 3 for transporting a metallic collector layer 4 to the mixer 2 and a second roller 3. ' for applying in the mixer 8th produced composites 8th on the collector layer 4 ,

The mixer 2 is in several areas 5 to 7 divided up. In a catchment area 5 become a binder mixture 9 , an active material 10 and a carrier liquid 18 dosed and in a mixing area 6 to the composite 8th finally mixed in a discharge area 7 on the metallic collector layer 4 is applied.

At the beginning of the process are the binder components of the binder mixture 9 and / or the active material 10 preferably as a powder, suspension or concentrated solution. This allows a simple dosage, for example by weighing or pipetting of the individual components, and mixing.

Before the components of the composite 8th in the mixing area 6 of the mixer 2 are mixed, the binder mixture 9 first in a pre-mixer 11 produced. The premixer 11 is preferably heatable, so that in powder form, as a suspension or solution in the premixer 11 metered introduced binder components of the binder mixture 9 are heated to a temperature above their respective glass transition temperature. This causes the binder components of the binder mixture to go 9 , which are carboxymethylcellulose 12 (CMC), styrene-butadiene rubber 13 (SBR) and polytetrafluoroethylene 14 (PTFE), in a viscous melt or mass over.

The binder mix 9 is then dosed into the mixing area 6 transferred where it is with the active material 10 and the carrier liquid 18 to the, preferably plastically deformable, composite 8th mixed, in particular kneaded, is.

The supplied or in the composite 8th contained amount of carrier liquid 18 is comparatively low and is preferably at most 20% by weight of the composite 8th , The carrier liquid is, for example, acetone, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), alcohol or water.

Optionally, as a further component, a dispersant (not shown), such as polyvinylpyrrolidone (PVP), are added, through which a particularly good mixing of the components 9 respectively. 12 - 14 . 10 and 18 promoted and stabilized.

In the supplied active material 10 which preferably comprises a lithium intercalating material such as carbon, graphite and / or silicon, may optionally contain an electroconductive additive such as conductive black or conductive graphite. Alternatively, an electrical conductive additive may also be separately (not shown) to the mixing area 6 be supplied.

To the binder mixture 9 or the composite 8th It is also possible to process well in the mixing area 6 preferably heated, so that in the mixing area 6 a temperature prevails which is above the glass transition temperature or softening temperature of the binder components or of the binder mixture 9 lies. Preferably, the glass transition or softening temperature by the added or in the mixing area 6 carrier liquid present 18 opposite the glass transition or softening temperature of the individual binder components 12 - 14 or the binder mixture 9 reduced.

The produced composite 8th will be in the discharge area 7 on the metallic collector layer 4 applied. The discharge area 7 points to an outlet nozzle 15 on, over which the composite 8th the mixer 2 leaves. The emerging composite 8th gets through the second roller 3. ' , preferably under a predetermined pressure, on the collector layer 4 laminated. The discharge area 7 , in particular the second roller 3. ' and / or the outlet nozzle 15 , is preferably also heatable, so that the composite 8th also when passing through the discharge area 7 or the outlet nozzle 15 , in particular when applied to the collector layer 4 through the second roller 3. ' , is maintained at a temperature above the glass transition temperature of the binder components 12 - 14 or the binder mixture 9 lies. Preferably, this temperature is also high enough to the composite 8th through the outlet nozzle 15 and / or the second roller 3. ' on the collector layer 4 to apply.

For a uniform application of the composite 8th on the collector layer 4 ensure the collector layer 4 through the first roller 3 to the outlet nozzle 15 on or past this. Here, the rotational speed of the first roller 3 and thus the transport speed of the collector layer 4 to the dosage of the composite 8th through the outlet nozzle 15 adjusted so that a desired amount of the composite 8th on the collector layer 4 is applied. Thereby and / or by adjusting the distance of the second roller 3. ' can the layer thickness of the composite 8th be set.

In another embodiment, the second roller 3. ' not part of the discharge area 7 , In particular, the second roller 3. ' along with the first roller 3 Part of a transport system for the collector layer 4 be.

The first roller 3 is preferably also heated, so that via the roller 3 running collector layer 4 is heated to a temperature above the glass transition temperature of the binder components 12 - 14 or the binder mixture 9 lies. This will be at the location of the outlet nozzle 15 the temperature conditions for laminating the composite 8th on the collector layer 4 Fulfills. In particular, this reliably prevents the composite 8th when hitting the collector layer 4 cools too much and no longer on the collector layer 4 can be laminated.

Preferably, the metallic collector layer 4 before applying the composite 8th pretreated. In the example shown, with the aid of a pretreatment nozzle 16 a layer of a bonding agent 17 For example, a thermoplastic film of a co-polyolefin, co-polyamide, co-polyester or polyurethane, PVdF, PVdF-HFP, acrylate polymer on the collector layer 4 applied. Here is the dosage of the mediator 17 through the pre-treatment nozzle 16 on the rotational speed of the first roller 3 adjusted so that the layer thickness of the mediator 17 a fraction of the following through the outlet nozzle 15 and / or second roller 3. ' certain layer thickness of the composite 8th is, for example, 50%, 25% or 20% of the layer thickness of the composite 8th , This will increase the adhesion of the composite 8th on the collector layer 4 advantageously increased.

Alternatively or additionally to the application of the adhesion promoter 17 can the pretreatment nozzle 16 also be designed to the metallic collector layer 4 to etch. By roughening, cleaning or activating the surface of the collector layer caused thereby 4 becomes the adhesion of the composite 8th on the collector layer 4 also advantageously increased.

During application and / or after application of the composite 8th on the collector layer 4 becomes the composite 8th removed the carrier liquid contained therein. Due to the comparatively small proportion of the carrier liquid in the total mass of the composite 8th For example, it is possible by heating the first and / or second roller 3 respectively. 3. ' and / or the collector foil 4 an evaporation or evaporation of the carrier liquid from the composite 8th already during the order to effect or promote. Alternatively or additionally, after the application of the composite, the carrier liquid can also be removed by heating the collector-composite composite and / or generating a negative pressure.

The device described enables a low-solvent and thus safe, environmentally friendly and reliable production of the composite 8th or the electrode.

A negative electrode with very good mechanical properties in the further processing, for example by punching, cutting and winding, as well as in operation, for example, obtained by a composite 8th from 3% by weight binder mixture 9 (CMC, SBR and PTFE), 87% by weight of active material 10 (of which 86% by weight of lithium intercalating material and 1% by weight of electrically conductive material) and 10% by weight of demineralized water, preferably at a temperature above the glass transition temperature of the binder mixture 9 or the binder components 12 - 14 , mixed and the resulting plastically deformable mass is laminated to a 12 micron thick copper foil, which is coated with a 2 micron thick adhesion promoter.

Based on the total weight of the dried composite 8th (ie after removal of the carrier liquid), this preferably contains 1% by weight of carboxymethylcellulose 12 (CMC), 1% by weight of styrene-butadiene rubber 13 (SBR), 1% by weight polytetrafluoroethylene 14 (PTFE), 96% by weight artificial porous graphite (eg Hitachi SMG A3) and 1% by weight conductive black (Super C45, Imerys).

LIST OF REFERENCE NUMBERS

1

contraption

2

mixer

3, 3 '

roll

4

metallic collector layer

5

catchment area

6

mixing area

7

discharge area

8th

composite

9

binder mixture

10

active material

11

premixer

12

Carboxymethylcellulose (CMC)

13

Styrene butadiene rubber (SBR)

14

Polytetrafluoroethylene (PTFE)

15

exhaust nozzle

16

Vorbehandlungsdüse

17

bonding agent

18

carrier fluid

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• DIN EN ISO 306 [0020]

Claims (14)

Method for producing an electrode for an electrochemical energy storage cell, in particular a lithium-ion cell, comprising the following steps: - producing a, in particular plastically deformable, composite ( 8th ) which comprises the following components: carboxymethylcellulose ( 12 ), Styrene-butadiene rubber ( 13 ), Polytetrafluoroethylene ( 14 ), Active material ( 10 ) and carrier liquid ( 18 ), wherein the proportion of the carrier liquid ( 18 ) on the composite ( 8th ) is not more than 20% by weight, - application of the composite ( 8th ) on a metallic collector layer ( 4 ) and - removing the carrier liquid ( 18 ) from the composite ( 8th ). Process according to claim 1, wherein the carrier liquid ( 18 ) at least one aprotic-polar solvent, in particular acetone, N-methyl-2-pyrrolidone (NMP) or N-ethyl-2-pyrrolidone (NEP), or a protic-polar solvent, in particular ethanol or water. Method according to one of the preceding claims, wherein the proportion of the carrier liquid ( 18 ) on the composite ( 8th ) at most 15% by weight, in particular at most 10% by weight. Method according to one of the preceding claims, wherein the production of the composite ( 8th ) by mixing the components ( 10 . 12 - 14 . 18 ) at a temperature above the glass transition temperature of one or more of the following binder components ( 12 - 14 ): carboxymethylcellulose ( 12 ), Styrene-butadiene rubber ( 13 ) and polytetrafluoroethylene ( 14 ). Method according to claim 4, wherein the mixing of the components ( 10 . 12 - 14 . 18 ) is carried out at a temperature which is between the glass transition temperature and the melting temperature of the binder components ( 12 - 14 ) lies. Method according to one of the preceding claims, wherein the components ( 10 . 12 - 14 . 18 ) are mixed by kneading. Method according to one of the preceding claims, wherein the application of the composite ( 8th ) on the metallic collector layer ( 4 ) by direct coating of the collector layer ( 4 ) with the composite ( 8th ) or lamination takes place. Method according to one of the preceding claims, wherein the active material ( 10 ) - contains a lithium intercalating material which contains carbon, in particular graphite, and / or silicon and / or - an electrically conductive material, in particular carbon black, graphite, other carbon-based materials, carbon nanotubes or a mixture thereof. Method according to one of the preceding claims, wherein the proportion of carboxymethylcellulose ( 12 ), Styrene-butadiene rubber ( 13 ) and polytetrafluoroethylene ( 14 ) together on the composite ( 8th ) is between 1 and 15% by weight. Method according to one of the preceding claims, wherein - the proportion of carboxymethylcellulose ( 12 ) on the binder components ( 12 - 14 ) is between 1 and 35% by weight and / or the proportion of styrene-butadiene rubber ( 13 ) on the binder components ( 12 - 14 ) is between 1 and 70% by weight and / or - the proportion of polytetrafluoroethylene ( 14 ) on the binder components ( 12 - 14 ) is between 1 and 50% by weight. Method according to one of the preceding claims, wherein the collector layer ( 4 ) before or during the application of the composite ( 8th ) is heated to a temperature which is above the glass transition temperature of one or more of the binder components ( 12 - 14 ), and / or the collector layer ( 4 ) is heated by these at least one heated roller ( 3 ) whose temperature is above the glass transition temperature of one or more of the binder components ( 12 - 14 ) lies. Method according to one of the preceding claims, wherein - the composite ( 8th ) by means of a template through which the composite ( 8th ) is brought into a predetermined shape and / or layer thickness, and / or by exerting a pressure on the metallic collector layer ( 4 ) is applied, and / or - the collector foil ( 4 ) before applying the composite ( 8th ) etched and / or, in particular with a bonding agent ( 17 ), is coated. Electrochemical energy storage cell, in particular a lithium-ion cell, having at least one electrode, comprising: a metallic collector layer ( 4 ) and - a dry composite applied to the metallic collector layer ( 8th ), which is obtainable by mixing carboxymethylcellulose ( 12 ), Styrene-butadiene rubber ( 13 ), Polytetrafluoroethylene ( 14 ), Active material ( 10 ) and carrier liquid ( 18 ), wherein the proportion of the carrier liquid ( 18 ) on the composite ( 8th ) is at most 20% by weight, and removal of the carrier liquid ( 18 ) from the composite ( 8th ) after the composite ( 8th ) has been applied to the metallic collector layer. Vehicle, in particular motor vehicle, with electrochemical energy storage cells according to claim 13.

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