EP3794660A1

EP3794660A1 - Device for the electrochemical processing of components of a battery cell, method for operating same and use thereof

Info

Publication number: EP3794660A1
Application number: EP19721594.0A
Authority: EP
Inventors: Ulrich Berner
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-05-16
Filing date: 2019-04-30
Publication date: 2021-03-24
Also published as: WO2019219380A1; DE102018207649A1

Abstract

The invention relates to a device for producing components for battery cells, in particular lithium-containing battery cells, having a holding device (12) for reversibly holding a substrate (14) to be coated, and having a coating device (16), wherein the coating device (16) comprises a cavity (20) carrying coating agent (18) and delimited by walls, and wherein at least some of the walls are at least partly formed by an electrically contacted electrode (26, 26a, 26b, 28).

Description

description

title

Device for electrochemical machining of components of a

Battery cell, method of operating the same and their use

The present invention relates to a device for

electrochemical machining of components of a battery cell and a method of operating the same and their use according to the preamble of the independent claims.

State of the art

Batteries are usually used to store electrical energy. With these one differentiates so-called primary batteries, which can be loaded only once and so-called secondary batteries, which are several times rechargeable. Typically, such batteries include a plurality of individual battery cells. In the area of secondary battery cells, too

Accumulators called, in particular so-called lithium-ion battery cells use. These are u. a. through a high

Energy density, good thermal stability and extremely low self-discharge. Accumulators based on lithium-ion battery cells thus find u. a. Application in motor vehicles such as in particular electric vehicles (EV), hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (PHEV).

Lithium-ion battery cells each include a cathode as positive

Electrode and an anode as a negative electrode. Both electrodes each comprise a metallic current collector, on or on which an electrochemical active material is applied, on the surface of which the electrical Electricity storage underlying electrochemical processes run off. For example, metal oxides are usually used as active material for cathodes. For anodes today usually carbonaceous active materials such as graphite or amorphous carbon (hard carbon) are used or silicon or a lithium titanate. If metallic lithium is used as the electrode material, then this serves as a current conductor geichzeitig.

Recent developments are aimed at the use of lithium metal as

Active material of the anode. As a separator such lithium metal-containing

Battery cells are used in particular solid electrolyte materials. These support in a deposition of lithium, for example, when charging the battery cell a flat level deposition of metallic lithium in the anode and prevent lithium grows up in the form of dendrites. For this purpose, predominantly rigid, in particular polymeric, solid electrolytes with a submicron or nanostructure are used. These are also included

Operating temperatures of such a battery cell in the range of about 80 ° C able to afford a corresponding mechanical support of the anode formed of lithium metal. Typical polymer electrolytes used, for example polyethylene oxide (PEO) based, are liquid at temperatures above these operating temperatures. However, starting from 180 ° C., lithium in metallic form is itself liquid and a separator which is likewise liquid in this area can not prevent the contact between the lithium used and a cathode of the battery cell. This would lead to safety-critical conditions in the battery cell.

Such solid electrolyte cells also have the advantage that on the

Use of organic solvents can be dispensed with. These represent a safety risk, especially at higher temperatures, since they tend to decompose in this area or are flammable. In addition, these tend to chemical reactions with electrodes containing metallic lithium.

The prerequisite is, however, that such solvents are sufficiently carefully removed after the preparation of the corresponding components of a battery cell. Usually, for such drying processes used elevated temperatures or a suppression. Furthermore, such components of a battery cell with a corresponding gas stream of a solvent-free gas can be applied to the

To increase the mass transfer coefficient between the battery cell component to be dried and the environment. When using this method, however, the effort to remove low residual concentration of solvents from the fabricated battery cell components increases disproportionately to the lower the loading of the battery cell components to be produced with residual solvent.

In this regard, from US 2016/344080 a metal-air battery is known in which the air supplied to the battery is cleaned before entering via a cleaning unit. The cleaning is done by the absorption of impurities. In this way, for example, water can be removed from the supplied air.

Furthermore, from US 2012/106017 a monitoring device in a motor vehicle battery is known, for example, determines the water content within the battery. In this way, safety-critical conditions can be avoided.

The production of battery cells, or of electrodes and separators of battery cells is usually carried out with the aid of solvents, for example, corresponding suspensions or slurries on a

applied appropriate substrate and then dried. However, the operation of such battery cells requires that only very small amounts of solvent residues and water exist in the interior of the same. Therefore, at the present time, the generated

Coatings partly undergo a complex drying process. An alternative to this is the use of solvent-free processes for the production of electrodes and separators for battery cells. For example, if a corresponding electrode by means of such

Dry prepared, for example, a mixture of a

Electrolytes with an electrode active material without using a

Solvent brought into a flowable state and then applied to a corresponding substrate. A similar procedure is also possible in the production of separators or solid electrolytes. In this case, the resulting electrodes or separators contain no solvent residues, but it can still be expected with small amounts of water, which are bound in the material of the electrode or the separator. These are ultimately difficult to remove.

Disclosure of the invention

According to the invention, an apparatus for producing components for battery cells, a method for operating the same and their use with the characterizing features of the independent claims

proposed.

Accordingly, an apparatus for the production of components for battery cells, in particular for lithium-containing battery cells, is provided, which in addition to a receiving device for reversibly receiving a

coating substrate further comprises a coating device. This comprises a cavity for guiding a coating agent. The cavity itself is limited by walls, wherein at least part of the walls is at least partially formed by an electrode. The electrode is electrically contacted, so that within the cavity in a simple manner, an electrochemical machining of the coating composition is possible.

Further advantageous embodiments of the present invention are

Subject of the dependent claims.

Thus, it is advantageous if the cavity provided within the coating device has two electrodes for guiding a coating agent, these at least partially being two

Form opposite walls of the cavity or are integrated into two corresponding opposite walls of the cavity. In this way it is ensured that a high proportion of a guided through the cavity coating agent can be subjected to an electrochemical treatment. It is particularly advantageous if those walls of the cavity, which contain an electrode, have a larger surface area in contact with a coating medium to be guided than walls of the cavity, which have no electrode. In particular, it is advantageous if the surface of walls containing electrodes is at least five times as large as the surface of walls which do not contain an electrode. In this way it is achieved that the distance of those walls to each other, the

Contain electrodes in proportion to the total cross section of the

Coating means leading cavity is relatively low and in this way a high conversion rate of an electrochemical treatment of the guided in the cavity coating agent is achieved.

Similarly, it is advantageous if the longitudinal extent of a

Coating agent leading cavity in the flow direction of the

Coating agent is greater than transverse to the flow direction of the

Coating means, as in this way a guided in the cavity

Coating agent over a longer period between electrodes of the walls of the cavity and thus a corresponding

electrochemical treatment is exposed.

According to a particularly advantageous embodiment of the present invention

According to the invention, the device comprises a means for translational movement of the receiving device and / or the coating agent, so that during a coating the receiving device and the coating agent can be guided relative to each other in the longitudinal direction of a substrate to be coated. In this way, a particularly uniform coating of a substrate to be coated within the device can be ensured.

According to a particularly advantageous embodiment of the present invention

The invention comprises the device for the production of components for

Battery cell control means for controlling a voltage source, by means of which a voltage to electrodes of the coating means of the

Device can be created. The control means comprises, for example, a memory for suitable voltage values or voltage profiles.

Furthermore, it is possible to stored or stored in a map Voltage values or voltage curves in correlation with in the

Coating to store existing or expected ingredients. In this way can be decomposed by applying a suitable voltage to the electrodes of the coating device, for example, by electrochemical means contained solvent residues or water. If it is already known in advance which solvent residues or whether water is to be expected in a corresponding coating agent, the control means can be used to apply an electrode to the electrodes

Coating applied voltage or a corresponding voltage curve can be selected accordingly in advance. It is also possible to address several ingredients of the coating agent in that successively different voltages or

Voltage curves are applied to electrodes of the coating device.

The invention further provides a method for producing components of battery cells, in particular lithium-containing battery cells. The method initially comprises the step of accommodating a substrate to be coated in a receiving device of a device for producing components for battery cells. In a second step, a suitable voltage is applied to electrodes of the coating device. Thereafter, a coating agent is passed through a cavity of the coating apparatus and brought into contact with the electrodes of the coating apparatus. Thereafter, a coating of the substrate with the

Coating agents.

This approach makes it possible, in an advantageous manner

electrochemical treatment of the coating composition, for example in the form of drying or removal of solvent residues to couple with the coating process itself and thus to be able to ensure an anhydrous coating, for example, a substrate in a simple manner.

The device according to the invention or the method for operating the same can be advantageously used for the production of components for Bateriezellen, especially for Baterien, which find application in mobile applications such as electric vehicles, hybrid vehicles and plug-in hybrid vehicles, in portable applications of telecommunications, home improvement or gardening equipment as well as in stationary Bateriesystemen example, for the storage of renewable electrical energy.

Brief description of the drawings

Advantageous embodiments of the present invention are in the

Drawing clarified and explained in more detail in the following description of the figures. It shows:

Figure 1 is a schematic sectional view of an apparatus for producing components for Bateriezellen according to a first

Embodiment of the present invention

FIG. 2 shows a schematic plan view of the device according to FIG. 1,

Figure 3 is a schematic plan view of an apparatus for the production of

Components for Bateriezellen according to a second embodiment of the present invention and

FIG. 4 shows a flow chart for the representation of an inventive device

Process for the production of components for battery cells.

FIG. 1 shows an apparatus for producing components for

Bateriezellen according to a first embodiment of the present invention shown. The device 10 comprises, for example, a receiving device 12 for receiving a coating to be coated within the device 10

Substrate 14. Furthermore, the device 10 comprises a

Coating device 16, by means of which the substrate 14 to be coated can be provided with a coating agent 18. In this case, the coating agent 18 passes through the coating device 16, for example, in the flow direction illustrated by an arrow 24. The

Coating device 16 comprises a coating medium supply 17 as well a cavity 20 and a coating nozzle 22. The

Coating agent supply 17, the cavity 20 and the coating nozzle 22 are passed through by the coating agent 18 in succession. In this case, the coating device 16 is designed, for example, as a so-called slot caster, in which the coating agent 18 already leaves the coating nozzle 22 in a layered form.

In walls of the cavity 20, for example, a first and a second electrode 26, 28 are integrated. Alternatively, walls of the cavity 20 are formed by the first and second electrodes 26, 28 at least partially or also over the entire surface. Surfaces of the first and second electrodes 26, 28 face the interior of the cavity 20 and are in contact with the interior of the cavity

Coating means 18. Furthermore, a voltage source 30 is provided, which is electrically conductively connected to the first and second electrodes 26, 28. By means of the voltage source 30, a voltage can be applied to the first and second electrodes 26, 28.

For controlling the voltage source 30, a control means 32 is provided, by means of which the voltage source 30 is given a corresponding voltage value. For this purpose, the control means 32 contains, for example, a memory or a map in which suitable voltage values or also voltage profiles are stored. In addition, it is possible to correlate corresponding voltage values or voltage profiles with actually contained or expected ingredients of the coating composition. If it is known, for example, that the coating agent contains water, a voltage value assigned to the ingredient water can be applied to the water via a corresponding characteristic field of the control means 32

Voltage source 30 transmitted and the corresponding voltage to the electrodes 26, 28 are applied. In this way it is possible, for example, to electrochemically decompose water contained in the operating medium 18 and thus to remove it from the coating agent 18.

Similarly, in existence or suspected existence of residues of a particular solvent in the coating agent 18 a the

Solvent assigned voltage value via the control means 32 the there stored map removed and a voltage applied to the electrodes 26, 28 voltage can be selected accordingly. In this way, solvent residues from the coating agent 18 can be removed oxidatively or reductively.

To the widest possible electrochemical treatment of

To ensure coating agent 18 within the cavity 20, the extent of walls defining the cavity 20 and containing one of the electrodes 26, 28, made larger than that of walls of the cavity 20, the none of the electrodes 26, 26 a, 26 b, 28 contain. If the electrodes 26, 28 are integrated, for example, in a bottom and a top surface of the cavity 20, the cavity 20 is designed, for example, such that the width of the cavity 20 is significantly greater than the height of the cavity 20. Thus, the width of the cavity 20 be in this case, for example, at least five times its height.

Furthermore, it is advantageous if the longitudinal extent of the cavity 20 in the flow direction 24 of the coating agent 18 is made larger, in particular at least twice as large as its width. In this way, the distance between the first and second electrodes 26, 28 is particularly low and yet a flow zone of the coating agent 18 between the

Electrodes 26, 28 particularly large. Both measures, individually or in combination, allow sufficiently good electrochemical treatment of the coating agent 18 within the coating device 16.

FIG. 2 shows the device according to FIG. 1 in a schematic plan view. Visible is the areal extent of the first electrode 26 and the embodiment of the coating device 16 in the form of a slot caster.

FIG. 3 shows a coating device 16 of a device 10 for

Production of components for battery cells according to a second

Embodiment of the present invention. Same reference numerals

denote the same component components as in FIGS. 1 and 2. In this embodiment of the device 10, the cavity 20 comprises a first electrode 26 in two-part form, comprising a first first electrode 26a and a second first electrode 26b and corresponding thereto and not shown in Figure 3, a first second electrode and a second second electrode. Correspondingly, two voltage sources 30a, 30b are provided, wherein a first voltage source 30a is electrically conductively connected to the first first electrode 26a and the first second electrode and the second voltage source 30b to the second first electrode 26b and the second second not shown in FIG Electrode.

The advantage of this embodiment is that the coating agent 18 when passing through the coating device 16 successively exposed to different electrochemical stresses and thus different electrochemical reactions within the

Coating agent can be triggered. In this way, for example, in the region of the first electrodes in the flow direction, a first electrochemical reaction such as, for example, a drying of the

Coating means 18 are carried out and in the region of the second electrodes subsequently a second electrochemical reaction as

for example, the removal of a solvent contained in the coating agent. This procedure can also be done in reverse order.

FIG. 4 schematically illustrates a method for producing components for battery cells by means of a device illustrated in FIGS. 1 to 3. Thus, in a first method step 40, for example, a substrate 14 is received in a receiving device 12 of the device 10.

In a second step 42, for example, a coating device 16 is brought into an initial position, in which a coating of the substrate 14 with a coating agent 18 can take place. Furthermore, in a third step 44, a voltage at electrodes 26, 26 a, 26 b, 28 of the

Coating device 16 applied. The third step 44 can also take place simultaneously with the step 42 or else in chronological order before it. In a fourth step 46, the substrate 14 is then coated with the coating agent 18. Preferably, a translational movement of the coating device 16 and the receiving device 12 takes place in such a way that the coating device 16 translates above the substrate 14 in the coating direction or longitudinal direction of the substrate 14 becomes. Finally, in a fifth step, the removal of the coated substrate 14 from the receiving device 12.

The device according to the invention or the method according to the invention for operating the same are preferably used for the production of

Battery cells for batteries in mobile applications, such as electric vehicles, hybrid vehicles or plug-in hybrid vehicles, for portable telecommunications applications, DIY or garden tools, as well as batteries in stationary energy storage, for example, for the storage of renewable electrical energy.

Claims

claims

1. Device for the production of components for battery cells,

in particular lithium-containing battery cells, with a receiving device (12) for reversibly receiving a substrate (14) to be coated and with a coating device (16), characterized in that the coating device (16) has a cavity (20) bounded by walls (20) ), wherein at least a part of the walls at least partially by an electrically

contacted electrode (26, 26 a, 26 b, 28) is formed.

2. Apparatus according to claim 1, characterized in that the

Coating device (16) has a cavity for guiding a

Coating means (18), wherein the two opposite

Walls each at least partially by an electrode (26, 26a, 26b, 28) is formed or in which an electrode (26, 26a, 26b, 28) is integrated.

3. A device according to claim 2, characterized in that an electrode (26, 26 a, 26 b, 28) comprising walls of the cavity (20) have a larger coating the surface (18) facing surface than the walls of the cavity (20) without electrode, In particular, the electrode-containing walls have at least five times as large

Area on like the walls without electrode.

4. Apparatus according to claim 2 or 3, characterized in that a longitudinal extent of the cavity (20) for guiding a

Coating means (18) in the flow direction of the coating means (18) is greater than the extent of the cavity (20) perpendicular to the flow direction of the coating means (18), in particular twice as large.

5. Device according to one of the preceding claims, characterized

characterized in that a translational means is provided to the Receiving device (12) and the coating device (16) relative to each other translationally in the longitudinal direction of a to be coated

Substrate (14) to move.

6. Device according to one of the preceding claims, characterized

in that a voltage source (30, 30a, 30b) for applying a voltage to electrodes (26, 26a, 26b, 28) of the

Coating device (16) is provided.

7. Apparatus according to claim 6, characterized in that a

Control means (32) for controlling the voltage source (30, 30a, 30b) is provided, wherein the control means (32) comprises a memory or a map, is provided in the voltage values or voltage waveforms in particular in correlation to in the coating means (18) contained ingredients ,

8. Method for the production of components of a battery cell,

in particular a lithium-containing battery cell, using a device according to one of the preceding claims, characterized in that in a first step (40), first to

coating substrate (14) is received by a receiving device (12) of the device for producing components for battery cells (10), in a second step (42) to a voltage

Electrodes (26, 26a, 26b, 28) of a coating device (16) is applied, in a third step (44) a coating agent (18) through a cavity (20) of the coating device (16) is guided, such that the coating agent ( 18) comes into contact with the electrodes (26, 26a, 26b, 28) of the coating device (16) and in a fourth step (46) is applied to a surface of the substrate (14) to form a coating.

9. The method according to claim 8, characterized in that temporally

consecutively different voltages or voltage profiles are applied to electrodes (26, 26a, 26b, 28) of the coating device (16).

10. Use of a device according to one of claims 1 to 7 or a method according to one of claims 8 to 9 for the production of

Battery cells for mobile applications such as batteries in electric vehicles, hybrid vehicles or plug-in hybrid vehicles, in batteries for

Home improvement applications, in batteries for gardening equipment, in batteries for portable applications of telecommunications or in batteries for storing in particular regeneratively generated electrical energy.