METHOD AND DEVICE FOR TRACTING THE ORIGIN OF A BATTERY CELL COMPONENT

Description

[0001] The invention relates to a method and a device for tracing the origin of a battery cell component.

[0002] Component manufacturers have a strong interest in having the most comprehensive knowledge possible about the origin of their manufactured components, extending beyond the manufacturing process itself. This involves more than simply tracing the origin of a component on the market back to its manufacturer. Rather, it is also in the manufacturers' interest to possess knowledge of the manufacturing factors associated with each individual component, such as the materials used, their origins, and the machinery employed. This knowledge not only ensures the quality of the component but also allows for the identification of other components that are likely to be similarly defective due to a subsequently discovered flaw in one component on the market, for example, because they are affected by the same material or manufacturing defect.This allows manufacturers to selectively recall only those components that were manufactured under the same conditions and where the discovered defect is also expected. Therefore, a unique marking of the component for traceability can prevent the need to recall all components.

[0003] However, not all components can be marked accordingly without impairing their overall visual appearance.

[0004] An example of a composite workpiece for which a permanent marking is proposed that should not affect the overall visual appearance is known from WO 2018 046357 A1. The marking there is achieved by bonding a metallic and a non-metallic top layer together, with the metallic top layer having a marking profile on the side facing the non-metallic top layer. Thus, the marking remains undetectable from the outside but can be detected by means of a suitable detection device.

[0005] Document US 2021 00175553 A1 describes an acoustic signal-based analysis of batteries.

[0006] Furthermore, there are components that, for technical reasons, cannot be marked at all or only with great difficulty without impairing their function. The use of conventional markings has proven particularly challenging in the field of battery cell components. Battery cell components often exhibit various physical surface properties that complicate marking. Moreover, their intermediate products are sometimes wound into reels in very large batches exceeding 1000 meters in length, and only the reels themselves are marked.

[0007] The invention therefore aims to develop a method and a device which enables the tracing of the origin for a larger number of component types without impairing the function and overall optical impression of the components.

[0008] The above problem is solved by a method and a device according to the independent claims. Preferred embodiments are the subject of the respective dependent claims.

[0009] A first aspect of the invention relates to a method for tracing the origin of a battery cell component. The method comprises the following steps: Capturing a first footprint indicative of an individual and unique surface structure of a first intermediate product of a battery cell component to be manufactured, using a first sensor unit, and determining the origin of a battery cell component to be checked using the first footprint and a second footprint indicative of an individual and unique surface structure of the battery cell component to be checked.

[0010] The invention is based on the insight that each manufactured intermediate product of a battery cell component has an individual and unique surface structure that can be traced along the manufacturing process chain to the final product. According to the invention, this uniqueness of the surface structures is represented in a characteristic footprint. During the manufacturing of a battery cell component, various footprints for the individual intermediate products can be recorded along its process chain. By comparing a first footprint of a first intermediate product of a battery cell component with a second footprint of a later intermediate or final product of the battery cell component along the process chain, it is possible to determine whether the intermediate or final product of the battery cell component to be examined can be attributed to the first intermediate product or not.In other words, comparing the two footprints allows the origin of a battery cell component to be traced back to the intermediate product in the manufacturing process without affecting the intermediate or final product. In particular, no structural modification of the intermediate or final product, such as by burning or printing a mark, is required.

[0011] The footprints used for comparison can naturally contain different levels of information. This is because the first intermediate product is often produced in a very large batch and is divided into numerous smaller intermediate or final products during the manufacturing process. Therefore, the first footprint can contain information about the surface structure of many smaller subsequent intermediate and final products. Similarly, the second footprint contains information about a surface structure that may only correspond to a small section of the first footprint.

[0012] Preferably, the respective footprints are indicative of the surface structure and a near-surface structure of the respective intermediate and / or final product. For example, the near-surface structure comprises a region of 0.5 mm, preferably 0.25 mm, and particularly preferably 0.1 mm below the surface structure of the respective intermediate and / or final product. By additionally scanning the near-surface structure, the information depth of the footprints can be increased and the reliability of the traceability improved.

[0013] In a preferred embodiment, the battery cell component is an electrode. The first intermediate product preferably comprises a carrier film coated with electrodes. For example, the carrier film is a metal foil made of copper and / or aluminum. The length of the electrode-coated carrier film can be at least 10 m, preferably at least 100 m, and particularly preferably at least 1000 m. It is also preferably the case that the electrode-coated carrier film is rolled into a roll.

[0014] Alternatively, the battery cell component can be a separator. The first intermediate product is preferably a separator film comprising a multitude of separators.

[0015] In a further preferred embodiment, a plurality of footprints are detected by means of the first sensor unit, wherein the footprints are indicative of a surface structure of a first intermediate product from a plurality of battery cell components, and the origin of the battery cell component to be inspected is determined using the plurality of footprints. In other words, preferably a footprint for the first intermediate product of a plurality of battery cell components, in particular for each battery cell component, is detected and preferably stored in a database. The database then serves as the basis for a virtual marking of the battery cell components. A database completely populated for every manufactured battery cell component can, for example, be used in liability cases to clarify the origin of the battery cell component.Furthermore, such a database offers the advantage that dealers, processors, and consumers can record a digital footprint (the second digital footprint) of the battery cell component on the market and, by querying the database, determine whether it is a genuine battery cell component from the manufacturer or not. In this way, counterfeit protection for battery cell components can be achieved.

[0016] In a further preferred embodiment, the first sensor unit comprises a first ultrasonic transmitter and a first ultrasonic receiver for detecting the first footprint. Ultrasonic sensors are cost-effective and detect not only surface structures but also near-surface structures. The advantages of information about near-surface structures have already been explained above. In this preferred embodiment, the first footprint is based on an ultrasonic spectrum of the surface and near-surface structure of the first intermediate of the battery cell component to be manufactured, and the second footprint is based on an ultrasonic spectrum of the surface and near-surface structure of the battery cell component to be inspected.

[0017] Preferably, the first ultrasound receiver and the first ultrasound transmitter are arranged on the same side or, alternatively, on opposite sides of the first intermediate product. The arrangement of the ultrasound receiver and transmitter determines whether primarily ultrasound reflection signals or transmission signals are detected. Arranging the ultrasound receiver and transmitter on the same side of the intermediate product is easier to integrate into a manufacturing plant and is therefore particularly preferred.

[0018] Alternatively or additionally, the first sensor unit can comprise an optical and / or electromagnetic sensor for capturing the first footprint. Accordingly, the footprints can comprise optical or electromagnetic spectra of the surface structure of the battery cell components. Optical sensors are cost-effective and ideally suited for capturing surface structures, while electromagnetic sensors can also capture information about the material properties of the battery cell components. Material properties can include, for example, the density and / or material composition of the battery cell component. Therefore, the footprints can also be indicative of a material property of the battery cell component to be manufactured, particularly in the case of an electromagnetic sensor. Preferably, the first sensor unit can comprise any combination of the sensors described above.By combining different sensor types, the information depth of the footprints can be increased and / or redundancy can be created, thereby improving the reliability of the tracking.

[0019] In a further preferred embodiment, the procedure also comprises the following steps: After capturing the first footprint using the first sensor unit, a process step is carried out to transfer the first intermediate product into a second intermediate product and to capture a third footprint, which is indicative of a surface structure of the second intermediate product of the battery cell component to be manufactured, using a second sensor unit, wherein the origin of the battery cell component to be checked is further determined using the third footprint.

[0020] In the production of battery cell components, the intermediate products along the process chain are fundamentally changed from one process step to the next. For the sake of clarity, only one process step will be referred to below. Of course, the teaching disclosed herein can also be applied to several process steps, and the advantages of the invention can be achieved analogously.

[0021] In this preferred embodiment, the first intermediate product is transformed into a second intermediate product by the change induced in the process step. The second intermediate product is therefore identical to the first, differing only in that it has undergone a change due to the process step. This change can influence the surface structure of the first intermediate product, thus altering the surface structure of the second intermediate product accordingly. Therefore, in this preferred embodiment, the surface structure of the second intermediate product is captured by a third footprint using a second sensor unit. Preferably, the third footprint is stored in the database along with information corresponding to the first footprint.Using corresponding information regarding the first and third footprints, it is therefore possible to infer the surface structure of the first intermediate product from the surface structure of the second intermediate product.

[0022] Exemplary process steps include calendering, drying, and splitting the first intermediate. Calendering and drying, in particular, can significantly influence the surface structure of the (first) intermediate. Preferably, the first intermediate is a roll of electrode-coated film, and the second intermediate is a calendered roll, a split calendered roll, or a detached electrode awaiting drying. Alternatively, the first intermediate can be a calendered roll of electrode-coated film, with the second intermediate then being a split calendered roll or a detached electrode awaiting drying.Furthermore, the first intermediate product can be a split calendered roll of an electrode-coated film, with the second intermediate product then being a separated electrode that still needs to be dried.

[0023] With the third footprint and the corresponding information relating to the first footprint, the changes in the surface structure of the first intermediate product caused by process steps along the process chain, which are also reflected in the final product, i.e. the battery cell component to be tested, can be taken into account and the origin can be traced more reliably.

[0024] Preferably, the second footprint is compared with the third footprint. Based on the result of this comparison, the origin of the battery cell component under inspection is then determined. If a match is found between the second and third footprints, the origin of the battery cell component under inspection can be traced back to the first intermediate product using the corresponding information between the first and third footprints.

[0025] In a further preferred embodiment, the first sensor unit comprises a neural network trained using training data and / or the second sensor unit comprises a second ultrasound transmitter and a second ultrasound receiver for capturing the third footprint. This allows the first footprint to be captured using the trained neural network. A suitably trained neural network has the advantage of acting as a virtual sensor, potentially eliminating the need for a physical sensor. This simplifies the capture of the first footprint and saves on the cost of additional sensors.

[0026] The training data preferably comprises a multitude of training footprints and a multitude of modified training footprints, where the training footprints are indicative of a surface structure of a first intermediate from a multitude of battery cell components, and the modified training footprints are indicative of a surface structure of a second intermediate from the multitude of battery cell components. Such structured training data can improve the performance of the neural network, enabling it to reconstruct a first footprint with a sufficiently small error.

[0027] Another aspect of the invention relates to a device for tracing the origin of a battery cell component. The device comprises a first sensor unit for detecting a first footprint, which is indicative of an individual and unique surface structure of a first intermediate product of a battery cell component to be manufactured, and a control unit configured to carry out the above method, in particular to determine the origin of a battery cell component to be inspected using the first footprint and a second footprint, which is indicative of an individual and unique surface structure of the battery cell component to be inspected. The features and advantages described in connection with the method can be applied analogously to the device. Therefore, a repetitive description is essentially omitted.

[0028] In a preferred embodiment, the first sensor unit comprises a first ultrasound transmitter and a first ultrasound receiver for detecting the first footprint.

[0029] In a further preferred embodiment, the device comprises a processing unit for carrying out a process step to convert the first intermediate product into a second intermediate product and a second sensor unit for detecting a third footprint that is indicative of a surface structure of the second intermediate product of the battery cell component to be manufactured, wherein the control unit is further configured to determine the origin of the battery cell component to be checked using the third footprint.

[0030] Preferably, the control unit is configured to compare the second footprint with the third footprint and, based on the result of the comparison, to determine the origin of the battery cell component to be checked.

[0031] Preferably, the first sensor unit includes a neural network trained using training data to detect the first footprint and / or the second sensor unit includes a second ultrasound transmitter and a second ultrasound receiver to detect the third footprint.

[0032] In a further preferred embodiment, the device has a storage unit on which the training data are stored, wherein the training data comprise a plurality of training footprints and a plurality of modified training footprints, wherein the training footprints are indicative of a surface structure of a first intermediate product of a plurality of battery cell components and the modified training footprints are indicative of a surface structure of a second intermediate product of the plurality of battery cell components.

[0033] In a further preferred embodiment, the first sensor unit has a third sensor for detecting a material property of the battery cell component to be manufactured, and the first footprint is also indicative of the material property of the battery cell component to be manufactured.

[0034] Further preferred embodiments of the invention result from the other features mentioned in the dependent claims.

[0035] Unless otherwise stated in individual cases, the various embodiments of the invention mentioned in this application can be advantageously combined with one another.

[0036] The invention is explained below using exemplary embodiments with reference to the accompanying drawings. These show: Figure 1 is a schematic representation of a method according to the invention according to an implementation form; and Figure 2 is a schematic representation of a method according to the invention according to an implementation form using a neural network.

[0037] Figure 1Figure 1 shows a schematic representation of a method according to the invention for tracing the origin of a battery cell component according to a specific embodiment. With this method, the origin of a battery cell component, such as an electrode or a separator, can be traced without having to structurally modify the battery cell component for marking purposes. The method and the device according to the invention are described below using an electrode as an example of a battery cell component and in relation to an electrode manufacturing process chain. First, the process chain is described in order to then explain the method and the device according to the invention in relation to it.

[0038] Figure 1The upper half of the figure schematically shows a process chain for producing a variety of electrodes that can be used as electrode-separator-electrode pairs in the manufacture of accumulators. In a first step, a roll 38, consisting of a rolled-up metal foil made of copper and / or aluminum, is provided, and the metal foil of the roll 38 is coated with a variety of electrodes. This process is also known as slurry coating. The resulting roll of coated metal foil represents a first intermediate product 12 along the process chain. The first intermediate product 12 is then processed, for example, in a further process step using a calender to produce a second intermediate product 30.Since the surface structure of the first intermediate product 12 is altered by calendering, the second intermediate product 30 has a surface structure that differs from that of the first intermediate product 12. The second intermediate product 30 is therefore a calendered, coated roll. In a further process step, this is transformed into a third intermediate product 40, 42. Here, the calendered coated roll is, for example, divided into two cut, calendered, coated rolls. The numerous electrodes are then manufactured from these rolls.

[0039] The inventive method will be explained by way of example using three electrodes from the plurality of manufactured electrodes. The three electrodes are battery cell components 18, 20, 22 to be tested. Figure 1The electrode-separator-electrode pairs used for the production of accumulators are shown as battery cell components 14 to be manufactured.

[0040] In the method according to the invention, a first footprint 10, which is indicative of a surface structure of the first intermediate product 12 of the battery cell component 14 to be manufactured, is first detected by means of a first sensor unit 16. The first footprint depicts the unique surface structure of the first intermediate product 12 and serves as a basis for tracing the origin of the battery cell component 18, 20, 22 to be inspected. For detecting further footprints of intermediate and / or end products, a second sensor unit 34 and a third sensor unit 36 ​​are available by way of example.

[0041] The third sensor unit 36 ​​detects a second footprint 24, 26, 28 for each battery cell component 18, 20, 22 to be inspected, which is indicative of a surface structure of the respective battery cell component 18, 20, 22. The second sensor unit 34, on the other hand, detects a third footprint 32, which is indicative of a surface structure of the second intermediate product 30 of the battery cell component 14 to be manufactured. The footprints can be stored in a memory (not shown). Furthermore, a correspondingly configured control unit (not shown) can be provided to detect the respective footprints 10, 24, 26, 28, 32 using the sensor units 16, 34, 36.

[0042] The in Figure 1The depicted footprints 10, 24, 26, 28, and 32 each show an ultrasound spectrum of reflected ultrasound signals from the corresponding surface structures and near-surface structures of the respective intermediate products 12, 18, 20, 22, and 30. The ordinate represents the strength (magnitude) of the ultrasound signal, while the abscissa represents spatial information along the surface structure of the respective intermediate products 12, 18, 20, 22, and 30. Since the metal foils used in the rolls 38 are, for example, 1000 m long, a range of values ​​from 0 to 1000 m is indicated on the abscissa of the first and third footprints 10 and 32.

[0043] To determine the origin of the battery cell component 18, 20, 22 under inspection, the first footprint 10 is compared with the second footprint 24, 26, 28. This can be done using a dedicated control unit. If the respective ultrasound spectra of the first footprint 10 and the second footprint 24, 26, 28 match, the unique surface structures depicted in the footprints allow the conclusion that the battery cell component 18, 20, 22 under inspection originated from the first intermediate product 12. It is irrelevant whether the electrodes, as the battery cell component 18, 20, 22 under inspection, come directly from production or are already on the market, as long as the electrodes are not subject to significant structural changes, such as mechanical or thermal damage, that substantially alter the surface structure.

[0044] Looking at the ultrasound spectra of the first and third footprints 10, 32, the mechanical change in the surface structure caused by the calendering process is noticeable in the ultrasound spectra. For example, the change in the surface structure is clearly indicated by a low intensity of the recorded ultrasound spectrum. Such changes can lead to the origin of the battery cell component 18, 20, 22 being tested no longer being reliably determined.

[0045] However, the mechanical and thermal changes along the process chain depend on the manufacturing conditions and are therefore characteristic, i.e., predictable to a certain extent. In this respect, process-related changes in the surface structure of the intermediate products 12, 30 can be taken into account by recording a footprint 10 before and a footprint 32 after the process steps that alter the surface structure, and a correlation between the corresponding footprints 10, 32 can be determined.

[0046] As exemplified in Figure 1As shown, the second footprint 24, 26, 28 each corresponds to a section of the third footprint 32. Therefore, by comparing the second footprint 24, 26, 28 with the third footprint 32, it can be determined whether the battery cell component 18, 20, 22 under test originated from the second intermediate product 30. Using the known correlation between the first and third footprints 10, 32 described above, a conclusion can then be drawn from the battery cell component 18, 20, 22 under test to the first intermediate product 12. In other words, the origin of the battery cell component 18, 20, 22 under test can thus be determined.

[0047] Numerous drying steps can occur during electrode manufacturing, which may also alter the surface structure of the intermediate products. For example, the manufactured batch of electrodes may be subjected to a further processing step in the form of a drying step. Although such a drying step in Figure 1 Although not shown, this factor should not be disregarded, as it can cause a change in the surface structure of the electrodes. However, thermally induced changes in the surface structure can be taken into account analogously using the correlation determination approach described above.

[0048] Figure 2Figure 1 shows a schematic representation of a method according to the invention according to one embodiment using a neural network 44. Using a neural network 44, a physical sensor can be omitted. For the purpose of illustrating the operating principle of the neural network 44, the method is shown only in part. Figure 2 The descriptions are presented as follows. Therefore, a repetitive description of already described features is omitted.

[0049] The second footprint 26 belonging to the battery cell component 20 under inspection is also compared with the third footprint 32 in this implementation, and its origin for the second intermediate product 30 is determined. Since no real sensor is available in this implementation to detect the exemplary first footprint 10, the first footprint 10 is replaced by a virtually detected first footprint 10'. The virtually detected first footprint 10' is calculated from the third footprint 32 by a neural network 44 trained using supervised learning. This is possible for each individual production line because the changes in the surface structures are deterministically determined by the manufacturing factors of each production line.

[0050] The neural network 44 was trained with training data specific to the specific manufacturing facility. The training data comprise a variety of training footprints and a variety of modified training footprints, where the training footprints are indicative of each surface structure of the first intermediate 12 of a variety of battery cell components, and the modified training footprints are indicative of each surface structure of the second intermediate 30 of the variety of battery cell components.

[0051] The first footprint 10' virtually captured by the neural network 44 can thus be assigned to the first intermediate product 12 and the origin of the battery cell component 20 to be checked can be traced back to the first intermediate product 12. Reference symbol list

[0052] 10, 10'first footprint 12first intermediate 14battery cell component to be manufactured 16first sensor unit 18-22battery cell component to be checked 24-28second footprint 30second intermediate 32third footprint 34second sensor unit 36third sensor unit 38roll 40, 42third intermediate

Claims

1. Method for tracing a source of a battery cell component, comprising the following steps: detecting a first footprint (10, 10'), which is indicative of an individual and unique surface structure of a first intermediate product (12) of a battery cell component (14) to be manufactured, by means of a first sensor unit (16) and determining a source of a battery cell component (18, 20, 22) to be tested, using the first footprint (10, 10') and a second footprint (24, 26, 28), which is indicative of an individual and unique surface structure of the battery cell component (18, 20, 22) to be tested.

2. Method according to Claim 1, characterized in that the battery cell component is an electrode or a separator.

3. Method according to either one of the preceding claims, characterized in that a plurality of footprints are detected by means of the first sensor unit (16), wherein the footprints are indicative of each surface structure of a first intermediate product (12) of a plurality of battery cell components and the source of the battery cell component (18, 20, 22) to be tested is determined using the plurality of footprints.

4. Method according to any one of the preceding claims, characterized in that the first sensor unit (16) comprises a first ultrasonic transmitter and a first ultrasonic receiver for detecting the first footprint (10, 10').

5. Method according to any one of the preceding claims, further characterized by the following steps: after detecting the first footprint (10, 10') by means of the first sensor unit (16), performing a process step for transforming the first intermediate product (12) into a second intermediate product (30), detecting a third footprint (32), which is indicative of a surface structure of the second intermediate product (30) of the battery cell component (14) to be manufactured, by means of a second sensor unit (34), wherein the source of the battery cell component (18, 20, 22) to be tested is furthermore determined using the third footprint (32).

6. Method according to Claim 5, characterized in that the second footprint (24, 26, 28) is compared with the third footprint (32) and the source of the battery cell component (18, 20, 22) to be tested is determined based on a result of the comparison.

7. Method according to Claim 5 or 6, characterized in that the first sensor unit (16) comprises a neural network (44) trained by means of training data and / or the second sensor unit (34) comprises a second ultrasonic transmitter and a second ultrasonic receiver for detecting the third footprint (32).

8. Method according to Claim 7, characterized in that the training data include a plurality of training footprints and a plurality of modified training footprints, wherein the training footprints are indicative of each surface structure of a first intermediate product (12) of a plurality of battery cell components and the modified training footprints are indicative of each surface structure of a second intermediate product (30) of the plurality of battery cell components.

9. Device for tracing a source of a battery cell component, comprising: a first sensor unit (16) for detecting a first footprint (10, 10'), which is indicative of an individual and unique surface structure of a first intermediate product (12) of a battery cell component (14) to be manufactured, and a control unit, which is set up to perform the method according to any one of the preceding claims.

10. Device according to Claim 9, characterized in that the first sensor unit (12) comprises a first ultrasonic transmitter and a first ultrasonic receiver for detecting the first footprint (10, 10').

11. Device according to Claim 9 or 10, characterized by: a processing unit for performing a process step for transforming the first intermediate product (12) into a second intermediate product (30) and a second sensor unit (34) for detecting a third footprint (32), which is indicative of a surface structure of the second intermediate product (30) of the battery cell component (14) to be manufactured, wherein the control unit is furthermore set up to determine the source of the battery cell component (18, 20, 22) to be tested using the third footprint (32).

12. Device according to Claim 11, characterized in that the control unit is set up to compare the second footprint (24, 26, 28) with the third footprint (32) and to determine the source of the battery cell component (18, 20, 22) to be tested based on a result of the comparison.

13. Device according to Claim 11 or 12, characterized in that the first sensor unit (12) comprises a neural network (44) trained by means of training data for detecting the first footprint (10, 10') and / or the second sensor unit (34) comprises a second ultrasonic transmitter and a second ultrasonic receiver for detecting the third footprint (32).

14. Device according to Claim 13, characterized by a storage unit on which the training data are stored, wherein the training data include a plurality of training footprints and a plurality of modified training footprints, wherein the training footprints are indicative of each surface structure of a first intermediate product (12) of a plurality of battery cell components and the modified training footprints are indicative of each surface structure of a second intermediate product (30) of the plurality of battery cell components.

15. Device according to any one of Claims 9 to 14, characterized in that the first sensor unit (12) comprises a third sensor for detecting a material property of the battery cell component (14) to be manufactured and the first footprint (10, 10') is further indicative of the material property of the battery cell component (14) to be manufactured.