Battery electrode for an electrochemical battery cell

Abstract

To provide an appropriate battery cell for an electrochemical battery cell.SOLUTION: The present invention relates to a battery electrode 2' for an electrochemical battery cell, the battery electrode including a metal current conductor 4 and a primary layer 6 provided in the current conductor. The primer layer 6 includes a conductive additive 8 and an electrochemically active silicon-based nano active material 10. The silicon-based active material layer 14 is applied on the primer layer 6.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a battery electrode for an electrochemical battery cell, comprising a metal current conductor and a primer layer provided on the current conductor. Furthermore, the present invention relates to an electrochemical battery cell having such a battery electrode.

Background Art

[0002] A vehicle with a prime mover driven or drivable electrically or by an electric motor, such as an electric vehicle or a hybrid vehicle, typically includes an electric motor capable of driving one vehicle axle or both vehicle axles. The electric motor is usually connected to a (high-voltage) battery inside the vehicle as an electrical energy storage unit to supply electrical energy.

[0003] In particular, an electrochemical battery cell can be understood here and hereinafter as a secondary battery of a so-called vehicle with a prime mover. In such a (secondary) vehicle battery, the chemical energy consumed can be repeatedly generated using an electrical charging process. Such a vehicle battery is configured, for example, as an electrochemical storage battery, particularly a lithium-ion storage battery.

[0004] Such a vehicle battery typically includes at least one battery module (battery cell module) in order to generate and provide a sufficiently large operating voltage. In the battery module, a plurality of individual battery cells are wired in a modular manner. Alternatively, a so-called Cell2Pack design is possible in which the battery cells are directly interconnected to the vehicle battery, particularly in parallel connection, and are not grouped into modules in advance.

[0005] The battery cell is configured, for example, as an electrochemical (thin) layer cell. The thin layer cell has a stacked structure having a cathode layer (cathode), an anode layer (anode), and a separator layer (separator) provided therebetween. Here, the anode and the cathode typically each comprise a current conductor (current collector, current collecting device, current collector, current arrester) provided with an active material (electrode material), particularly in the form of a film, and the active material can insert (store) lithium ions and can desorb (extract) lithium ions from the active material. The components are penetrated, for example, by a liquid electrolyte (electrolyte solution), which creates an ionic conductive bond or charge balancing of the components. To increase the energy density of the lithium-ion battery, silicon-based (Si-based) active materials are increasingly being used for the electrode layers, particularly for the anode.

[0006] Furthermore, it is desirable for the lithium-ion battery to have as long a lifespan as possible and as high a rapid chargeability as possible. In order to enable or improve the adhesion of the electrode coating in the current conductor and thereby improve the rapid chargeability, a copper film is used as the current conductor having a so-called primer layer or primer coating (English: Primer interlayer), particularly in the anode. The primer layer typically consists of conductive carbon (e.g., conductive soot) and a binder polymer that enables adhesion in the current conductor. The primer layer usually has a large roughness in order to improve the adhesion of the active material layer provided thereon.

[0007] However, such a primer layer has the drawback of reducing the energy density of the battery cell. This is because the primer layer contains an inert material (e.g., binder) and does not contain an Si-based material. Therefore, usually, the primer layer is applied as thinly as possible, i.e., with as small a layer thickness as possible, so that the negative impact on the energy density is reduced. Summary of the Invention

Problems to be Solved by the Invention

[0008] The problem underlying the present invention is to provide a battery electrode, in particular a particularly suitable one, for an electrochemical battery cell. Furthermore, the problem underlying the present invention is to provide a battery cell, in particular a particularly suitable one.

Means for Solving the Problems

[0009] According to the present invention, the above problems are solved with respect to the battery electrode by the features of claim 1 and with respect to the battery cell by the features of claim 10. Advantageous configurations and developments are the subject of the dependent claims. The advantages and configurations described with respect to the battery electrode are likewise transferable to the battery cell, and vice versa.

[0010] The battery electrode according to the present invention is provided for and is suitable and configured for an electrochemical battery cell. Here, the battery electrode comprises a metal, in particular film-shaped, current conductor (current collector, current collecting device, current collector, current arrester) and a primer layer provided thereon. The primer layer comprises, as components, a conductive additive and an electrochemically active silicon-based nanoactive material. Thereby, a particularly suitable battery electrode is realized.

[0011] Therefore, according to the present invention, a Si-based nanoactive material is additionally introduced into the primer layer together. The Si-based nanoactive material is electrochemically active and thus contributes to the capacity of the battery electrode, thereby increasing the energy density of the battery cell. Since the Si-based nanoactive material is introduced directly into the primer layer, good adhesion of the Si-based active material over the life of the battery cell is further ensured.

[0012] Here, the nano-active material can be understood as an active material in the form of nanoscopic materials or particles. The nano-active material is formed, for example, of nanoparticles or nanotubes or nanowires or mixtures thereof.

[0013] The battery electrode is particularly the anode, and the nano-active material can correspondingly be understood as the nano-anode active material. As the conductive additive, typically, for example, conductive additives used in battery anodes or primer layers such as conductive soot, carbon black, ketjen black, nanotubes, etc. are used.

[0014] At this time, the primer layer may not be coated. In other words, the battery electrode can be formed by a primed current conductor. However, preferably, an active material layer, particularly a silicon-based active material layer, is provided (coated) on the primer layer. Therefore, since, for example, an anode active material is provided (coated) on the primer layer, the battery electrode can be used as an anode in a battery cell. The conductivity and adhesiveness of the paste or active material layer in the battery electrode are improved by the primer layer.

[0015] Even by the addition of the nano-active material, the primer layer has only a slight influence on the energy density of the battery cell. In an advantageous configuration, in order to further reduce the influence, the primer layer has a layer thickness of only 100 nm (nanometers) to 5 μm (micrometers). In particular, a layer thickness of 500 nm to 1.5 μm is set.

[0016] Accordingly, in a suitable configuration, the nanoactive material, i.e., the nanoscopic material or particles, has an average size of 50 to 500 nm, particularly 50 to 250 nm. In other words, the primer layer has a layer thickness from several nanoactive material layers to a single layer. Thereby, the life of the battery electrode is advantageously extended. This is because so-called particle cracking and particle detachment are avoided. Accordingly, further, the formation of an unfavorable intermediate phase (SEI) is also advantageously avoided.

[0017] In one possible form, the nanoactive material is pure silicon (Si), silicon oxide (SiOx) or a silicon alloy (Si-alloy). For example, the nanoactive material is formed of Si nanoparticles, Si nanotubes, Si nanowires or SiOx nanomaterials doped with lithium (Li) or magnesium (Mg).

[0018] In a useful development form, the primer layer has a ratio of 99:1 to 1:99 for the mass percentage (wt%) of the conductive additive with respect to the nanoactive material. Preferably, the mass percentage ratio of the conductive additive with respect to the nanoactive material is set to 75:25 to 50:50.

[0019] The primer layer can be configured without a binder, i.e., without having a binder. As a coating method for such a primer layer without a binder, for example, Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), sputtering or Atomic Layer Deposition (ALD) is used.

[0020] However, the primer layer can also be composed with an additional binder. In such a configuration, the primer layer has a binder ratio of 2 to 40% by mass. Here, as the binder, for example, typical polymer binders known in battery anodes or primer layers (such as CMC, SBR, PAA, PVdF, PTFE...) are used. For the primer layer having a binder, as a coating method, for example, slot-die coating, doctor blade coating, or utilization of self-assembly of particle superstructures during a mixing process can be used. At this time, the coating process can be performed in a water-based or solvent-based manner. Alternatively, a dry coating method can also be considered.

[0021] According to a preferred embodiment, the current conductor is configured as a copper film. Preferably, the current conductor or the copper film has a layer thickness (film thickness) of 1 to 20 μm, particularly 4.5 to 10 μm, for example 6 μm.

[0022] The electrochemical battery cell according to the present invention includes the above-described battery electrodes. Here, the battery electrode is housed in the cell stack of the battery cell as an anode. Thereby, a particularly suitable battery cell having a particularly high energy density is ensured.

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0025] In all the figures, corresponding parts or sizes are denoted by the same reference numerals.

[0026] The battery electrode 2 shown in FIG. 1 is provided for and suitable and configured for an electrochemical battery cell (not shown). Here, the battery electrode 2 comprises a metallic, in particular film-shaped, current conductor (current collector, current collection device, current collector, current arrester) 4 and a primer layer 6 provided thereon.

[0027] The current conductor 4 is preferably configured as a copper film. At this time, the current conductor 4 has a layer thickness (film thickness) of 1 to 20 μm, in particular 4.5 to 10 μm, for example 6 μm.

[0028] The primer layer 6 has a layer thickness of 100 nm to 5 μm. In particular, the layer thickness is dimensioned between 500 nm and 1.5 μm. The primer layer 6 comprises a conductive additive 8 and an electrochemically active silicon-based nanoactive material 10. The conductive additive 8 is, for example, conductive soot, carbon black, ketjen black, nanotubes or a mixture thereof. The nanoactive material 10 is, for example, pure silicon (Si), silicon oxide (SiOx) or a silicon alloy (Si-alloy). For example, the nanoactive material is formed of Si nanoparticles, Si nanotubes, Si nanowires or SiOx nanomaterials doped with lithium (Li) or magnesium (Mg) or a mixture thereof. At this time, the nanoactive material 10 has an average size of 50 to 500 nm, in particular 50 to 250 nm.

[0029] The ratio (mass percent) of the conductive additive 8 to the nanoactive material 10 in the primer layer 6 is 99:1 to 1:99. Preferably, the ratio of the conductive additive 8 to the nanoactive material 10 is set to 75:25 to 50:50.

[0030] The primer layer 6 can be configured without a binder, that is, without having the binder 12. As a coating method for such a primer layer without a binder, for example, Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), sputtering, or Atomic Layer Deposition (ALD) is used.

[0031] However, the primer layer 6 can optionally also be configured with the binder 12. In such a configuration, the primer layer 6 has a binder ratio of 2 to 40% by mass. Here, as the binder 12, for example, typical polymer binders known in battery anodes or primer layers (such as CMC, SBR, PAA, PVdF, PTFE...) or mixtures are used. For the primer layer 6 having the binder 12, as a coating method, for example, slot-die coating, doctor blade coating, or utilization of self-assembly of particle superstructures during a mixing process can be used. At this time, the coating process can be carried out in a water-based or solvent-based manner. Instead of this, a dry coating method is also conceivable.

[0032] FIG. 2 shows a battery electrode 2' configured as an anode, in which the primer layer 6 acts as an adhesive layer for the silicon-based active material layer 14. Therefore, since the anode active material is applied as the active material layer 14 to the primer layer 6, the battery electrode 2' can be used as an anode in a battery cell.

[0033] The claimed invention is not limited to the above-described embodiments. Rather, other aspects of the present invention can be derived by those skilled in the art within the scope of the disclosed claims without departing from the subject matter of the claimed invention. Also, in particular, all individual features in the disclosed claims described in connection with the above embodiments can be combined in other aspects without departing from the subject matter of the claimed invention. The present invention may also include the following aspects: 1. A battery electrode (2, 2') for an electrochemical battery cell, comprising a metal current conductor (4) and a primer layer (6) provided on the current conductor, wherein the primer layer (6) comprises a conductive additive (8) and an electrochemically active silicon-based nanoactive material (10). 2. The battery electrode (2') according to 1. above, wherein a silicon-based active material layer (14) is coated on the primer layer (6). 3. The battery electrode (2, 2') according to 1. or 2. above, wherein the primer layer (6) has a layer thickness of 100 nm to 5 μm, particularly 500 nm to 1.5 μm. 4. The battery electrode (2, 2') according to any one of 1. to 3. above, wherein the nanoactive material (10) has an average size of 50 nm to 500 nm, particularly 50 nm to 250 nm. 5. The battery electrode (2, 2') according to any one of 1. to 4. above, wherein the nanoactive material (10) is pure silicon, silicon oxide or a silicon alloy. 6. The battery electrode (2, 2') according to any one of 1. to 5. above, wherein the primer layer (6) has a mass percentage ratio of the conductive additive (8) to the nanoactive material (10) of 99:1 to 1:99, particularly 75:20 to 50:50. 7. The battery electrode (2, 2') according to any one of 1. to 6. above, wherein the primer layer (6) further comprises a binder (12) having 2 to 40% by mass. 8. The battery electrode (2, 2') according to any one of 1. to 7. above, wherein the current conductor (4) is configured as a copper film. 9. The battery electrode (2, 2') according to any one of 1. to 8. above, wherein the current conductor (4) has a layer thickness of 1 to 20 μm, particularly 4.5 to 10 μm. 10. An electrochemical battery cell comprising the battery electrode (2, 2') according to any one of 1. to 9. above.

Explanation of Reference Numerals

[0034] 2,2’ battery electrode 4 current conductor 6 primer layer 8 conductive additive 10 nano active material 12 binder 14 active material layer

Claims

1. A battery electrode (2, 2') for an electrochemical battery cell, comprising a metal current conductor (4) and a primer layer (6) provided on the current conductor, wherein the primer layer (6) comprises a conductive additive (8) and an electrochemically active silicon-based nanoactive material (10), the nanoactive material (10) has an average size of 50 nm to 500 nm, and the primer layer (6) is configured without a binder.

2. The battery electrode (2') according to claim 1, wherein a silicon-based active material layer (14) is coated on the primer layer (6).

3. The battery electrode (2, 2') according to claim 1 or 2, wherein the primer layer (6) has a layer thickness of 100 nm to 5 μm.

4. The battery electrode (2, 2') according to claim 1 or 2, wherein the nanoactive material (10) is pure silicon, silicon oxide or a silicon alloy.

5. The battery electrode (2, 2') according to claim 1 or 2, wherein the primer layer (6) has a mass percentage ratio of the conductive additive (8) to the nanoactive material (10) of 99:1 to 1:

99.

6. The battery electrode (2, 2') according to claim 1 or 2, wherein the current conductor (4) is configured as a copper film.

7. The battery electrode (2, 2') according to claim 1 or 2, wherein the current conductor (4) has a layer thickness of 1 to 20 μm.

8. An electrochemical battery cell comprising the battery electrode (2, 2') according to claim 1 or 2.

Images