DE-102024132649-A1 - Method for measuring a reference body for a battery electrode stack

Abstract

Method for measuring a reference body (1) for a battery electrode stack (2), wherein the reference body (1) has a sequence (23) of directly successive and alternating reference layers K R (12) and reference layers A R (13), each of which has at least one reference outer edge (3, 4), where K R stands for cathode and A R for anode, wherein the method has - Measuring the reference bodies (1), in particular measuring them using a computed tomography method and obtaining a computed tomography reference measurement image (5a-5f) of the selected reference measurement area (S3), and - Distances (d AKR ) between the reference outer edges (3, 4) of the reference layers K R (12) and A R (13) are determined from a measurement result of the reference measurement method (S2) - the reference outer edges (3, 4) of the reference layers K R (12) and A R (13) are identified in the computed tomographic reference measurement image (5a-5f) using the distances between the reference outer edges (3, 4) of the reference layers K R (12) and A R (13) obtained from the measurement result of the reference measurement method (S4), - Based on the identified reference outer edges (3, 4) of the reference layers K R (12) and A R (13), reference measurement artifacts (6a, 6b, 6c) in the area of the reference outer edges (3, 4) of the reference layers K R (12) and A R (13) are identified in the computed tomographic reference measurement image (5a-5f) (S5).

Inventors

• Steffen Masuch

Assignees

• POWERCO SE

Dates

Publication Date

20260513

Application Date

20241108

Claims (14)

1. Method for measuring a reference body (1) for a battery electrode stack (2), wherein the reference body (1) has a sequence (23) of directly successive and alternating reference layers K _R (12) and reference layers A_R (13), each of which has at least one reference outer edge (3, 4), where K_R is the cathode and A _R is the anode, wherein the method comprises: - measuring the reference body (1) in at least one selected reference measurement area using a reference measurement method (S1); - determining distances (d _AKR ) between the reference outer edges (3, 4) of the reference layers K _R (12) and A_R (13) from a measurement result of the reference measurement method (S2); - measuring the reference body (1) in the at least one selected reference measurement area using a computed tomography method and obtaining a computed tomography reference measurement image (5a-5f) of the selected reference measurement area (S3); - the Reference outer edges (3, 4) of the reference layers K R (12) and A R (13) are identified in the computed tomography reference measurement image (5a-5f) using the distances between the reference outer edges (3, 4) of the reference layers K R (12) and A R (13) obtained from the measurement result of the reference measurement method (S4), - based on the identified reference outer edges (3, 4) of the reference layers K R (12) and A R (13) reference measurement artifacts (6a, 6b, 6c) in the area of the reference outer edges (3, 4) of the reference layers K R (12) and A R (13) are identified in the computed tomography reference measurement image (5a-5f) (S5).
2. Method for testing a battery electrode stack (2), wherein the battery electrode stack (2) comprises a sequence of alternating test layers K_P (14) and test layers A_P (15), each of which has at least one test outer edge (16, 17), wherein separator layers (8) may also be present in the battery electrode stack (2), where K_P represents cathode and A_P represents anode, wherein the method comprises: - measuring the battery electrode stack (2) in at least one selected test measurement area using a computed tomography method (S6) and obtaining a computed tomography test measurement image of the selected test measurement area, wherein the method further comprises: - identifying the test outer edges (16, 17) of the test layers K_P (14) and A _P (15) in the computed tomography test measurement image of the selected test measurement area (S7), wherein the identification of the test outer edges (16, 17) by a Comparison with a computed tomographic reference measurement image (5a-5f) is carried out, which is obtained according to a method for measuring a reference body (1) according to Claim 1 was obtained and in which reference outer edges (3, 4) of the reference layers K R (12) and A R (13) were identified, and/or - test measurement artifacts in the area of the test outer edges (16, 17) of the test layers K P (14) and A P (15) are identified in the computed tomographic test measurement image of the selected test measurement area (S8), wherein the identification of the test measurement artifacts is carried out by comparison with a computed tomographic reference measurement image (5a-5f) which was obtained according to a method for measuring a reference body (1) according to Claim 1 was obtained and in which reference measurement artifacts (6a, 6b, 6c) of the reference layers K R (12) and A R (13) were identified.
3. Method for testing a battery electrode stack (2) according to Claim 2 , comprising determining distances (S9) between the test outer edges (16, 17) of the test layers K P (14) and A P (15).
4. Method for testing a battery electrode stack (2) according to Claim 2 or 3 , comprising determining (S10) a pose of the test outer edge (16) of the test layer K P (14) relative to a predefined cathode placement surface (9).
5. Method for testing a battery electrode stack (2) according to one of the Claims 2 - 4 , comprising determining (S11) a pose of the test outer edge (17) of the test layer A P (15) relative to a predefined anode placement surface (10).
6. Method for testing a battery electrode stack (2) according to one of the Claims 2 - 5 , comprising determining (S12) a pose of the test outer edge (17) of the test layer A P (15) and the test outer edge (16) of the test layer K P (14) relative to a support (11) of the battery electrode stack (2).
7. Method for validating a test measurement method, which is particularly intended for testing a battery electrode stack, wherein the method uses a reference body (1) having a sequence (23) of directly successive and alternating reference layers K R (12) and reference layers A R (13), each having at least one reference outer edge (3, 4), where K R stands for cathode and A R for anode, and the method comprises: - the reference body (1) is measured at a first time point using the test measurement method (S13) and a first test measurement result is obtained, - the reference body (1) is then used at a second time point, The measurement is repeated at a later time using the test measurement method (S14) and a second test measurement result is obtained - it is determined (S15) whether there is a deviation between the second test measurement result and the first test measurement result.
8. Procedure according to Claim 7 , where the test measurement method is a method in which the reference body is irradiated with radiation.
9. Procedure according to Claim 7 or 8 , whereby the test measurement method is used to determine at least partially the relative position of the reference layers K R (12) and reference layers A R (13) to each other.
10. Procedure according to one of the Claims 7 - 9 , parallel to those in Claim 7 - 9 exhibiting the described activities with any frequency: - the reference body (1) is measured in at least one selected reference measurement area using a reference measurement method (S16) and the relative position of the reference layers K R (12) and reference layers A R (13) is determined at least partially, - the measurement (S17) and the determination of the relative position of the reference layers K R (12) and reference layers A R (13) is repeated at a later time, - it is determined (S18) whether the relative position of the reference layers K R (12) and the reference layers A R (13) has changed.
11. Reference body (1) for testing battery cells or validating a test measurement method, comprising a sequence (23) of directly successive, alternating reference layers K R (12) and A R (13), wherein K R stands for cathode and A R for anode, wherein no separator layer (8) is arranged between the reference layers K R (12) and A R (13).
12. Reference body (1) according to Claim 11 , comprising a holder (7) in which the sequence (23) of directly successive, alternating reference layers K R (12) and A R (13) is fixed, and in which the alternating reference layers K R (12) and A R (13) are fixed relative to each other.
13. Method for producing a reference body (1) for testing battery cells or validating a test measurement method, comprising: arranging reference layers K R (12) and A R (13), wherein K R stands for cathode and A R for anode, in an alternating sequence (23), wherein no separator layer (8) is arranged between the reference layers K R (12) and A R (13) and the reference layers K R (12) and A R (13) follow each other directly.
14. Use of a sequence (23) of directly successive, alternating reference layers K R (12) and A R (12), where K R stands for cathode and A R for anode, - as reference bodies (1) for identifying anode outer edges and cathode outer edges in a battery electrode stack (2) - for identifying measurement artifacts in the region of the anode outer edges in a battery electrode stack (2), and/or for validating a test measurement method.

Description

The present invention relates to a method for measuring a reference body for a battery electrode stack, a method for measuring a battery electrode stack, a method for validating a test measurement method, a reference body, a method for manufacturing the reference body and the use of the reference body. Battery cells feature an electrode-separator (ESV) stack. The ESV stack is manufactured in a single process during battery cell production. Depending on the process technology, the stack is either wound or stacked as individual sheets. The same criteria and requirements apply to both. The electrode placement accuracy and component tolerances influence the electrode position. The placement accuracy of the electrode layers (also called electrode sheets) within the ESV stack is the quality criterion for the process capability of the stacking process. Position is a safety- and function-relevant product characteristic of the ESV, necessitating 100% inspection during series production. These systems must be certified and require a test standard. Within the stack, it is crucial that all electrode corners maintain a defined distance from each other and fall within a defined tolerance range. The electrochemical performance of a battery cell deteriorates more rapidly during operation with reduced electrode coverage. Furthermore, a short circuit and battery cell failure can result from direct contact between the anode and cathode due to incorrect placement. Currently, the anode (negative) in an ESV (electrostatic discharge lamp) is, for example, 1.5 mm larger than the cathode (positive) to ensure complete overlap of the anode and cathode despite placement inaccuracies. Current efforts aim to reduce this 1.5 mm anode overhang to save material. The electrodes are therefore an internal feature and must be inspected using radiographic testing during series production. Currently, there is no test standard to implement acceptance testing according to VDA 5 or MSA. For the acceptance of test procedures and equipment in series production, the capability of a system must be demonstrated. Standard procedures are defined by MSA or VDA 5. These procedures require the existence of a test standard. A test standard, also known as a reference standard or, in this invention, a "reference body," is a known measure or value used for the validation of measuring instruments and measuring systems. In measurement system analysis (MSA), the test standard serves to determine and compare the accuracy and reliability of the measuring instrument or measuring system. The requirement for the test standard is that it reflects the properties of a subsequent test object, which is usually a product, in the manufacturing process "as accurately as possible." In this invention, the test object/product is also referred to as the "battery electrode stack," which represents the test object/product. Thus, an ideal test standard would be a real product that, however, does not change in its characteristic expression and can be measured using a reference measurement. In the mass production of battery cells, a radiographic test is used to check the position of the anodes and cathodes in the assembly. The DE 10 2018 102 412 A1 describes a method for determining calibration parameters of a measuring device for measuring an object with invasive radiation, in particular a measuring device for computed tomographic measurement of an object, which has a radiation source, a detector unit and a positioning device for recording and positioning an object in the beam path between the radiation source and the detector unit. Computed tomography (CT) is an imaging and measurement technique that calculates three-dimensional image information of the interior of an object or body through a series of radiographic images. This allows for the inspection and highly accurate measurement of internal features of the test object using CT data. Establishing a reference measurement for comparison of these internal features is very difficult, as the accuracy of the comparison measurement should be at least ten times higher. Since CT scans require large examination areas with very high resolution for inspecting internal features, it is not possible to obtain comparative measurements with another CT scan, as no CT scanner offers ten times the resolution of the systems used in the series. Therefore, a product cannot simply be made long-term stable and used as a test standard, as a system for performing the reference measurement is lacking. Creating a test standard for radiographic testing, such as computed tomography, is thus extremely challenging. A reference part made of aluminum or materials with the same properties and structure as the battery cell (comb structure, etc.) has the disadvantage that the battery cell properties cannot be identically replicated. This is because the battery cell is a multi-material composite with different layers. The purpose of the invention was to provide a solu