WO2019076592A1

WO2019076592A1 - Method for producing a battery cell and battery cell

Info

Publication number: WO2019076592A1
Application number: PCT/EP2018/076047
Authority: WO
Inventors: Martin Scherner; Johannes Proell
Original assignee: Robert Bosch Gmbh
Priority date: 2017-10-17
Filing date: 2018-09-26
Publication date: 2019-04-25
Also published as: DE102017218495A1

Abstract

The invention relates to a method for producing a battery cell (60) and to a battery cell (60). In order to produce a contact tab (14), an electrode material (8) is cut with a laser. The electrode material (8) comprises a foil material (10) and an active material (12) applied thereon. The foil material (10) is cut in a single pass cut (18) whereas the active material (12) is cut in a multiple pass cutting process (30). For the cutting process, a high-performance continuous wave laser is used.

Description

Description title

Method of manufacturing a battery cell and battery cell Technical field

The invention relates to a field for manufacturing a battery cell and to a battery cell, which are used in batteries for electric vehicles, hybrid vehicles and plug-in hybrid vehicles.

State of the art

JP 2012 221912 relates to a method for producing an electrode by means of a laser. A laser head that emits laser beams is moved along a predetermined cutting path at a predetermined cutting path

Movement speed operated. The laser power and the laser radiation are stored and specified corresponding to the change in the respective cutting region of the ribbon-like electrode material. The storage and setting of the laser light to a corresponding energy is made taking into account the elapsed time that has elapsed since the laser head has set in motion.

KR 2008 0101725 relates to a manufacturing method of an electrode of a lithium secondary battery. For this purpose, a pulsed laser is used, which produces minimal burr formation and minimal electrode dust formation, in particular in the cutting region, so that desired different

Dimensions of electrodes can be manufactured with only one cutting process.

In the mass production of lithium-ion batteries manufacturing is flags in correspondingly high quality, especially what the Cutting edges, still a technical challenge. The contact lugs are usually made during the advancing movement of band-shaped materials, so that high demands on the

Flexibility and fast mobility of the cutting tools, which are usually laser. Active materials, for example for the production of cathodes, for example, have a relatively high basis weight of more than 30 mg / cm ² and a relatively high film thickness, which is in the order of 200 μηη and more. To manufacture, for example, as cathodes formed electrodes, which at

Feed rates of> 0.5 m / s, high laser ablation rates are required. So far, only multiple cutting strategies have one

satisfactory cut quality and a satisfactory removal rate. Cathodes that are to be processed may have complex geometries between an active material and a contact tab transition zone. When producing contact lugs from the electrode material, radii of <3 mm must also be observed. These requirements for the

Production of tabs requires highly dynamic laser scanning techniques to represent the required small radii at high feed rates of film-like cathode material.

The active material of a cathode comprises lithiated transition metal oxides (NCA, i.e. LiNiCoAlO 2 or NCM, i.e. LiNiCoMnO 2, carbon black and a binder) The active material may lithiate up to 90% by weight and more

Transition metal oxides such as the NCA and NCM mentioned above, which presents a challenge to the processing. The laser processing of NCA and NCM containing active material on the cathode side produced on the re-solidified active material, particles and ridges on the cutting edges, which can penetrate a separator material and the

Failure of a battery cell may result due to forming short circuits. The cutting out of tabs must be done in part within the active material on the cathode side so as not to lose battery cell volume and to maintain the energy density. In contrast to laser cutting active material, cutting aluminum foil material is relatively easy; however, the cutting of the active material may increase lead to a significant reduction of the cutting speed and to a drastic reduction in the cut edge quality.

Presentation of the invention

According to the invention, a method for producing a battery cell is proposed in which at least the following method steps are performed:

Cutting an electrode material with a laser to produce a contact lug,

wherein the electrode material comprises a foil material and an active material applied thereto,

Cutting the foil material in a single cut and cutting the

Active material in a multi-section, and

whereby a continuous wave laser is used for the cutting.

By the solution proposed by the invention, relatively high cutting speeds can be realized because very high laser powers can be transferred to the active material of the electrode material. The

Multiple cutting by means of a laser realizes a relatively short

Laser material interaction. These periods of this interaction are quite comparable with pulsed laser systems, with which both high cutting speeds and a very high quality of the

make trained cutting edges realize. When inventively proposed multiple section of the active material of the thermal influence on the active material is significantly reduced, so that a

achieve excellent cut edge quality.

In a further development of the method proposed according to the invention, both the single cut of the film material and the multiple cut of the active material of the electrode material take place during the movement of the

Electrode material in the feed direction. As a result, a highly dynamic cutting process can be represented, while, on the one hand, a single cut in the relatively thin foil material of the electrode material and, on the other hand, a Multiple cut partially or completely in the active material of the electrode material can be made, and on the one hand the quality of the cut edges is very high and is ensured during the cutting process and on the other hand, the application rate is at a high level.

Following the method proposed according to the invention, the film material used in the electrode material is aluminum.

On the cathode side, steel foils or nickel foils could also be used. In the electrode material, there is used an active material containing lithiated transition metal oxides (NCA, i.e., LiNiCoAlO 2), NCM (LiNiCoMnO 2), carbon black, and a polymer binder. In addition, the active material may contain LiMn204, LiFePO4, LiNiO2, LiMnO2, LiCoO2, lithium-sulfur (Li2S), or even conversion materials. The multi-section of the electrode material advantageously comprises a first cut, a second cut and a further, third cut. The first cut occurs completely or partially within the active material of the electrode material, while the second cut occurs within the framework of the multiple cut within the active material. The multi-section third cut is made entirely or partially within the active material of the electrode material.

In the context of the method proposed according to the invention, the first cut and the third cut occur opposite to the advancing direction of the electrode material in the multiple cut, while the second cut takes place in the feed direction of the electrode material in the context of the multiple cut. This procedure saves process time. When driving against the feed direction, the scan speed can be reduced to introduce the same path energy (power / scan speed) into the material as moving in the feed direction. In addition, advantageously a process fine adjustment can take place in such a way that, for example, scanning or cutting can take place at the same speed, and thus the effective

Range energy could be minimally increased, which in turn leads to a gentler material removal.

The single cut of the sheet material of the electrode material may be part of the first cut or the third cut of the multiple cut. The A single cut of the sheet material is always both part of the first and part of the third cut, wherein both in the first cut and in the third cut each time an area is cut in the active material. Optionally, the upper horizontal cut in the sheet material may be part of the first or third cut to separate the electrode sheet from the electrode tape at precisely the upper edge of the electrode tape not equal to the upper horizontal edge of the cut edge electrode tab.

The single cut in the film material takes place in accordance with the invention

proposed method opposite to the feed direction of

Electrode material. The electrode material in roll form is in

Feed direction with a feed speed> 0.5 m / s moves.

The electrode material to be processed within the scope of the method proposed according to the invention has a thickness of> 200 μm, the basis weight of the electrode material being> 30 mg / cm ² and the cathodic active material> 90% by weight of lithiated transition metal oxides (NCA, NCM, LiMn204, LiFePO 4, LiNiO 2, LiMnO 2, LiCoO 2, lithium sulfur (Li 2S)) or conversion materials.

Furthermore, a battery cell is proposed which at least one

Electrode ensemble, comprising an electrode stack, which after the

According to the invention proposed method is prepared.

A battery cell according to the invention advantageously finds use in an electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV) or in a consumer electronics product. Under consumer electronics product are in particular mobile phones, tablet PCs or notebooks to understand.

Advantages of the invention

By inventively proposed solution can during the

Movement of the cathode material in the feed direction a cathode-side contact lug are generated, wherein a combined cutting strategy for Use comes in which the sheet material of the electrode material is processed in a single cut, while the active material is subjected to a multiple cut. Since the active material on the cathode side a relatively high

Has basis weight, can by the proposed method according to the invention in the multiple section of the active material a short

Laser beam material interaction can be achieved. The achievable

Interaction times are comparable to the interaction times that occur when using a pulsed laser. Another advantage is that cutting can be done faster than with pulsed systems, and even better edge qualities can be achieved with this cutting strategy compared to pulsed nanosecond systems typically used here. Due to the fact that a multiple cut is made in the active material of the electrode material, reduced thermal stresses occur, which act on the active material, whereby a very high cut edge quality is achieved. By the proposed method according to the invention a combination of a single cut with a multi-section, usually occur in laser cutting process re-solidified lots of active material, the occurrence of particles and electrode dust are avoided, which reduce the cut edge geometry of contact flags in terms of their quality so that it penetrates

Separator foils can come, which can lead to a short circuit of a battery cell in the worst case.

An application of the proposed method according to the invention avoids excessive thermal loads on the active material when cutting by means of a laser, so that the required cutting edge qualities in the production of the contact lugs during the advancement of the electrode material is achieved.

By the method proposed according to the invention, the cutting time is minimized and the movement of the electrode material within the period of the cut minimized, so that a highly effective combined

Achieve cutting strategy.

Furthermore, by the method proposed according to the invention, a region to be scanned can be minimized, since the effective cutting time is minimized becomes using highly dynamic scanner systems. It is possible to use fast and highly dynamic scanners which are suitable for high cutting speeds and have a relatively high scanning rate and can run off the smallest radii that are at the contact lugs at the transition point of

Active material in the actual contact lug are required. By the method proposed according to the invention, smaller laser spot sizes can be achieved, which have a relatively high energy density on the upper side of the material, so that a highly efficient laser cut is obtained.

In general, electrode bands are also inspected for imperfections in the material during processing, which is done via on-line image processing systems. Should such a faulty area be detected in the electrode band, then the cutting laser for this contact lug processing can also directly attach a laser mark on the contact lug in order to exclude this damaged electrode later from the process. Furthermore, there is the possibility that one and the same laser scanner system, due to its inherent dynamics marked each electrode on the AI surface, so as to ensure a clear assignment of the parts in a battery cell.

Brief description of the drawings

With reference to the drawing, the invention will be discussed in more detail below

described.

It shows:

Figure 1 is a plan view of an electrode material of the one

cathode-side contact lug is cut and which is transported in the feed direction,

Figure 2 is a view of the present invention proposed cutting strategy of single cut and multiple cut and a battery cell. variants

The illustration according to FIG. 1 shows the plan view of an electrode material 8 which contains a foil material 10 and an active material 12. The foil material 10 is in particular an aluminum foil, but steel foils or nickel foils could also be used. The active material 12 is lithiated transition metal oxides NCA, i. LiNiCoAlO 2), NCM (LiNiCoMnO 2), carbon black, and a polymer binder. Further, the active material 12 may include LiMn204, LiFePO 4, LiNiO 2, LiMnO 2, LiCoO 2, lithium sulfur (Li 2S), and generally also

Conversion materials included.

The electrode material 8 has a thickness of> 200 μηη. The

Basis weight of the electrode material 8 according to the plan view in Figure 1 is> 30 mg / cm ² , while the active material 12, which is used,> 90 wt .-% of lithiated transition metal oxides (NCA, NCM).

Reference numeral 14 denotes a contact lug, which is made of the

Electrode material 8, from film material 10 and active material 12 according to the dashed line in Figure 1 is cut out. From Figure 1 it can be seen that with respect to the edges 22, 24 of the active material 12, the film material 10 projects on both sides by a projection 16 with respect to the active material 12. This means that the film material 10 of the electrode material 8 is wider than the active material 12.

The electrode material 8 according to FIG. 1 is conveyed in the feed direction 20. The feed rate in the feed direction 20 of the electrode material 8 is> 0.5 m / s,

An outer edge of the sheet material 10 of the electrode material 8 is identified by reference numeral 26. At the transition point in the region of the first edge 22 of the active material 12, a cutting radius 28 is executed. The cutting radius is less than 3 mm. The representation of FIG. 2 essentially corresponds to the illustration of the electrode material 8 according to FIG. 1, but FIG. 2 schematically shows the cutting method proposed according to the invention

Single cut 18 and multiple cut 30 indicated. For explanation, it should be noted that the arrows shown in Figure 2 only the courses of the single section

18 and sections 40, 42, 44 of the multi-section 30 show. The

Driving through the single or multiple cuts 18, 30 also takes place along the line in dashed lines in FIG. 2 within the active material 12 and the film material 10 of the electrode material 8.

From FIG. 2 it can be seen that the electrode material 8 is moved in the feed direction 20. A contact lug 14 produced by a continuous wave laser essentially lies in the foil material 10 of the electrode material 8. The foil material 10 is, for example, a very thin foil of aluminum. The contact lug 14 as shown in Figure 2 is defined by a horizontal edge 34, a first vertical edge 36 and a second

Vertical edge 38 defined. In the region of the first edge 22 of the active material 12 is the cutting radius 28, which is <3 mm. Following the method proposed according to the invention, the first takes place

Section 40 of the multi-section 30 completely in the active material 12 and completely in the film material 10. In the first cut of the multi-section 30, the active material 12 either completely within this or partially along the first edge 22, the first vertical edge 36, the

Horizontal edge 34, the second vertical edge 38 and the cutting radius 28, which in the context of the first cut 40 again a cut in

Active material 12 sets along the dashed line. The single cut 18 along the horizontal edge 34 is part of the first cut 40 of the

Multiple cuts 30.

The second section 42 of the multi-section 30 always takes place through the

Active material 12, while the third section 44 is always completely within the active material 12 and completely within the sheet material 10.

According to the cutting strategy proposed according to the invention, there are always three cuts 40, 42, 44 in the context of the multiple cut 30 in the active material to achieve a very high cut edge quality on the one hand and on the other hand only a single cut 18 in the film material 10 instead. The first cut 40 and the third cut 44 always take place completely in the film material 10 as well as completely in the active material 12. From the perspective of the active material 12, however, this undergoes a total of three cuts. Due to the highly dynamic

traversed movements of the laser, its movement is comparable to a ship swinging motion.

The fact that the multiple section 30 comprises three sections 40, 42, 44, a very short laser beam material interaction can be achieved. These

Interaction times are quite comparable to the interaction times that can be achieved using pulsed lasers and have two beneficial effects, namely high cutting speeds and very high

Cutting edge quality. This is due to the fact that the active material is not thermally stressed so high, resulting in a high

Achieve cut edge quality. During the first cut 40 of the

Multiple section 30 counter to the feed direction 20 of the

The third cut 44 of the multiple cut 30 takes place counter to the feed direction 20 of the electrode material 8, so that during the advance of the electrode material 8 in the feed direction 20, the contact lug 14 is continuously formed, while the electrode material 8 is conveyed in a conveying plane and is usually unwound continuously from a reel supply received on a roll. The

Movement speed at which the electrode material 8 in

Feed direction 20 is promoted, is> 0.5 m / s.

The illustration according to FIG. 3 shows a battery cell 60. The battery cell 60 comprises a negative terminal 62 and a positive terminal 64. A voltage provided by the battery cell 60 can be tapped off via the terminals 62, 64. Furthermore, the battery cell 60 can be charged via the terminals 62, 64. The battery cell 60 includes a housing 66 and the housing 66 of the battery cell 60 is an electrode unit

arranged, which is designed as an electrode stack 68. The electrode stack 68 has a negative electrode, which is referred to as anode 70 and a positive electrode, referred to as cathode 72, on. The anode 70 and the cathode 72 are each made like a foil and separated by a separator 74. The separator 74 is ionically conductive, that is permeable to lithium ions, but electrically insulating.

The anode 70 comprises an anodic active material and an anodic current collector. The anodic current collector is made electrically conductive and made of a metal, for example copper. From the anodic current collector protrude tabs 76 of the anode 70 away. The tabs 76 of the anode 70 are connected to a negative collector element 78, which is connected to the negative terminal 62. Thus, the anodic

Current conductor electrically connected to the negative terminal 62 of the battery cell 60.

The cathode 72 includes the cathodic active material 12 and a

cathodic current collector. The cathodic current conductor is designed to be electrically conductive and made of a metal, for example aluminum. From the cathodic current collector contact tabs 14 project away from the cathode 72. The contact lugs 14 of the cathode 72 are positive

Collector element 80 is connected, which is connected to the positive terminal 64. Thus, the cathodic current collector is electrically connected to the positive terminal 64 of the battery cell 60.

The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, within the scope given by the claims a variety of modifications are possible, which are within the scope of expert action.

Claims

claims

1. Method for producing a battery cell (60) with the following method steps:

1.1 cutting an electrode material (8) with a laser for producing contact lugs (14),

1.2 wherein the electrode material (8) comprises a foil material (10) and an active material (12) applied thereto,

1.3 cutting the film material (10) in a single cut (18) and cutting the active material (12) in a multi-section (30),

1.4 using a high performance continuous wave laser for cutting.

2. The method according to claim 1, characterized in that the

Single cut (18) and the multiple cut (30) during the movement of the electrode material (8) in the feed direction (20) are made.

3. The method according to claim 1, characterized in that the

Foil material (10) is aluminum, steel or nickel.

4. The method according to claim 1, characterized in that a

Active material (12) is used, which lithiated

Transition metal oxides NCA (LiNiCoAlO 2), NCM (LiNiCoMnO 2), carbon black, a polymer binder, LiMn 2 O 4, LiFePO 4, LiNiO 2, LiMnO 2, LiCoO 2, lithium sulfur (Li 2S), and / or

Contains conversion materials. Method according to claim 1, characterized in that the multiple cut (30) according to method step 1.3 comprises a first cut (40), a second cut (42) and a further, third cut (44).

A method according to claim 5, characterized in that the first cut (40) is made entirely both within the active material (12) and completely within the film material (10).

A method according to claim 5, characterized in that the second cut (42) takes place within the active material (12).

A method according to claim 5, characterized in that the third cut (44) is made entirely both within the active material (12) and completely within the film material (10).

Method according to claim 5, characterized in that the first cut (40) and the third cut (44) are opposite to

Feed direction (20) of the electrode material (8) take place.

A method according to claim 5, characterized in that the second cut (2) in the feed direction (20) of the electrode material (8).

Method according to claims 1 and 5, characterized in that the single cut (18) according to method step 1.3 is part of the first cut (40) or the third cut (44) of the multiple cut (30).

A method according to claim 1, characterized in that the single cut (18) in the film material (10) opposite to

Feed direction (20) of the electrode material (8).

A method according to claim 1, characterized in that the electrode material (8) has a thickness of> 200 μηη.

14. The method according to claim 1, characterized in that the basis weight of the electrode material (8)> 30 mg / cm ² .

15. The method according to claim 1, characterized in that the

Active material (12)> 90% by weight of lithiated transition metal oxides (NCA, NCM).

16. Battery cell (60) comprising at least one electrode stack (68) produced by a method according to one of the preceding claims.

17. Use of a battery cell (60) according to claim 16 in one

Electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV) or a consumer electronics product.