Test body for testing a test system for testing battery cells, procedures and systems

Abstract

The present invention relates to a test body (30) for testing a test system for testing battery cells. Furthermore, the invention relates to a method for testing a test system for testing battery cells using such a test body (30), as well as to a system.The test body (30) is designed such that the test body (30) can be introduced into the test system instead of a battery cell, wherein the test body (30) has a gas release device (40), wherein the gas release device (40) has a receiving device (41) for receiving a test liquid, wherein the test liquid comprises a liquid electrolyte solution (15) or one or more components of the electrolyte solution (15) that are detectable by a sensor device of the test system, wherein the gas release device (40) is designed such that when the test liquid received in the receiving device (41) evaporates or evaporates, the gases (43) produced during the evaporation or evaporation reach the environment outside the test body (30).

Description

[0001] The present invention relates to a test body for testing a test system for testing battery cells. Furthermore, the invention relates to a method for testing a test system for testing battery cells using such a test body, as well as to a system.

[0002] Battery cells, such as lithium-ion cells, are widely used and are manufactured in various shapes. The most common shapes currently are round cells, prismatic cells, and pouch cells.

[0003] Battery cells typically have an electrode stack or coil, which typically includes several cathode and anode layers, as well as separator layers arranged between the cathode and anode layers. These are enclosed by an outer shell, for example, a flexible outer shell for pouch cells or a structurally stable outer shell for prismatic cells. The interior space enclosed by the outer shell, in which the electrode stack or coil is housed, is filled with an electrolyte or electrolyte solution to enable ion flow. Dimethyl carbonate can be a component of such an electrolyte solution.

[0004] Battery cells are typically tested in a testing facility after production (end of line (EOL)), for example, prior to delivery or as part of an incoming goods inspection. Typically, at least an OCV (Open Current Voltage) test and a leak test of the outer shell are performed. Once the tests are completed and all tests have been successfully passed, the battery cells can be used. Battery cells assessed as defective are generally disposed of.

[0005] DE 103 16 332 A1 discloses a method for testing the leak tightness of products. DE 10 2020 111 464 A1 and CN 108 332 817 A disclose further prior art.

[0006] It is essential for such testing systems that faulty battery cells are correctly identified. To achieve this, the individual test devices must be checked for proper functioning.

[0007] DE 10 2021 107 055 A1 discloses a test body for testing a test system for testing battery cells, which has the features of the preamble of claim 1. Furthermore, DE 10 2021 107 055 A1 discloses a method for testing a test system and a system comprising a test system and a test body. EP 2 447 694 A1 and CN 1 15 248 098 A also disclose test bodies for testing a test system.

[0008] In highly automated test systems, testing all stations or test devices is problematic because access to individual test devices can be difficult and the test system may have to be stopped during operation in order to carry out testing on individual test devices.

[0009] There is therefore a need to simplify testing of a test system for testing battery cells so that reliable testing of individual or even all test devices in the test system can be carried out, particularly during ongoing operation of the test system.

[0010] This problem is solved by the subject matter of the independent claims. The dependent claims concern advantageous further training.

[0011] The invention proposes a test body for testing a test system for testing battery cells. The battery cells to be tested have an interior space enclosed by an outer shell, wherein the interior space contains a liquid electrolyte solution. The test system has at least one leak testing device for testing the tightness of the outer shell. The leak testing device has a sensor device configured to detect one or more components of the electrolyte solution, for example, present in gaseous form due to evaporation, in an environment outside the outer shell of the battery cells to be tested. The test body is designed such that the test body can be introduced into the test system instead of a battery cell. The test body has a gas release device. The gas release device has a receiving device for receiving a test liquid.wherein the test liquid comprises the liquid electrolyte solution or comprises one or more, in particular volatile, components of the electrolyte solution that are detectable by the sensor device, wherein the gas release device is designed such that upon evaporation or evaporation of the test liquid held in the receiving device, the gases produced during the evaporation or evaporation reach the environment outside the test body.

[0012] The sensor device of the leak testing device can be tested using the test body described above. The gas release device provided in the test body can cause the test fluid in the leak testing device to evaporate or vaporize. The resulting gases are released into the environment and thus reach the sensor device of the leak testing device. If the leak testing device is functioning properly, they should be detected by the sensor device. The test body is designed in such a way that it can be inserted into the test system instead of a battery cell, thus making it usable in the test system instead of a battery cell.This has the advantage that, for example, transport devices, such as a gripper attached to a robot arm, can handle the test specimen like a battery cell, for example, to insert the test specimen into the leak testing device during ongoing operation of the test system and / or remove it from it, just as would be done with a battery cell. This has the advantage that, particularly during series production or series testing of a large number of battery cells, the test specimen can be inserted into the test system instead of such a battery cell and thus during ongoing operation, so that it is not necessary to stop the test system in order to test the leak testing device and, if necessary, other test devices.

[0013] In order to improve handling of the test body corresponding to a battery cell in the test system, it is considered particularly advantageous if the test body has a housing, wherein an outer contour of the housing corresponds to an outer shape of the battery cells to be tested.

[0014] The battery cells can be, for example, prismatic cells, pouch cells (also known as coffee bag cells), or round cells. Accordingly, the test body can have the outer contour of a prismatic cell, the outer contour of a pouch cell, or the outer contour of a round cell.

[0015] In a particularly preferred embodiment, the gas discharge device comprises a heating device, wherein the heating device is configured to heat the test liquid held in the receiving device to evaporate the test liquid. By providing a heating device, in particular a controllable heating device, the test liquid can be evaporated or vaporized in a targeted manner in the test device, thereby preventing contamination of other areas of the test system with components or gases of the test liquid.

[0016] It is considered particularly advantageous if the heating device has an electrical heating element, wherein the test body has an electrical energy storage device for supplying the heating element with electrical energy.

[0017] The heating element can, for example, be a heating mat.

[0018] In conjunction with an electric heating element, it is considered particularly advantageous if the test body has a control device for activating the heating element. This allows, for example, the heating element to be specifically activated when the test body is in the leak testing device.

[0019] In an advantageous development, the receiving device comprises a receiving chamber, wherein a carrier body made of an absorbent material is accommodated in the receiving chamber, wherein the carrier body can be impregnated with the test fluid. The carrier body prevents the test fluid from leaking out of the test body during handling of the test body, for example, during transport of the test body through the testing system, which could lead to contamination of components of the testing system with test fluid.

[0020] Preferably, the carrier body is removable and / or replaceable. This allows the carrier body to be impregnated with the test fluid outside the test body, making it easier to introduce the test fluid into the carrier body and preventing unwanted contact of the test fluid with other surfaces of the carrier body.

[0021] In a particularly preferred embodiment, it is provided that the gas release device is formed within the housing, wherein the housing has one or more through-openings in the region of the gas release device or a cover of the gas release device, wherein the gases reach the environment outside the test body via the one or more through-openings.

[0022] In connection with the receiving device, it is considered particularly advantageous if the receiving device has a receiving space that can be closed with a lid, wherein the lid has one or more through-openings, for example in the form of a perforation, wherein the gases produced during evaporation or vaporization reach the environment and thus also the sensor device of the leak testing device via these through-openings.

[0023] It is provided that the test body has a voltage source and one or more external contacting elements, wherein the one or more contacting elements are connected to the voltage source, wherein the voltage source is configured to provide an open-circuit voltage (OCV) at the one or more contacting elements that corresponds to the open-circuit voltage of the battery cells to be tested. This is particularly advantageous if the test system has a voltage testing device, for example, to test an open-circuit voltage of the battery cells to be tested. This open-circuit voltage is preferably in the range of 2 volts to 5 volts.This design allows the test specimen to pass a voltage test performed by a voltage testing device in the test system, allowing the test specimen to be transported to subsequent stations, particularly the subsequent test devices, within the test system and not rejected as defective during the voltage test. This is particularly advantageous when the leak test device is located downstream of the voltage testing device.

[0024] Since voltage testing typically involves testing the open-circuit voltage, it is not necessary for the voltage source to be able to supply a continuous current, as is the case with real battery cells. Accordingly, it is not necessary for the test object's voltage source to store a large amount of electrical charge. It is only necessary that the voltage source delivers an appropriate open-circuit voltage corresponding to that of a proper battery cell, since no current or only a negligible current flow occurs during an open-circuit voltage test or check. Especially in light of this, it is considered particularly advantageous if the voltage source is a capacitor.

[0025] The method according to the invention is used to test a test system for testing battery cells. The battery cells to be tested have an interior space enclosed by an outer shell, wherein the interior space contains a liquid electrolyte solution. The test system has at least one leak testing device for testing the tightness of the outer shell. The leak testing device has a sensor device configured to detect one or more components of the electrolyte solution in an environment outside the outer shell of the battery cells to be tested. The method is carried out using a test body according to the invention, wherein the method comprises: - Introducing the test liquid into the receiving device of the gas release device of the test body, - Inserting the test body into the leak testing device instead of a battery cell.

[0026] In particular, given that the method is carried out using the test body described above, the statements regarding the advantages and advantageous developments of the test body described above apply accordingly to the method and vice versa.

[0027] In a particularly preferred embodiment, it is provided that the test system has at least one further test device, wherein one of the at least one further test device is a voltage test device, wherein the voltage test device has a measuring device with a first measuring contact for contacting a first cell terminal of the battery cell to be tested and with a second measuring contact for contacting a second cell terminal of the battery cell to be tested, wherein the measuring device is designed to measure an open circuit voltage between the first cell terminal and the second cell terminal, wherein the test body has a voltage source and a first contacting element and a second contacting element, wherein the first and the second contacting element are connected to the voltage source, wherein the voltage source is designed toto provide an open-circuit voltage between the first contacting element and the second contacting element which corresponds to the open-circuit voltage of the battery cells to be tested, wherein the first contacting element and the second contacting element can be contacted by the first measuring contact and the second measuring contact, corresponding to the first cell terminal and the second cell terminal of the battery cells to be tested, wherein the test body is introduced into the voltage testing device instead of a battery cell.

[0028] In a preferred development, it is provided that the testing system has at least one further testing device and a transport device, wherein the transport device is designed to transport a battery cell introduced into the testing system from the further testing device to the leak testing device or from the leak testing device to the further testing device, wherein the test body is designed such that the transport device transports the test body introduced instead of the battery cell instead of the battery cell.

[0029] The system according to the invention comprises a testing system for testing battery cells and further comprises the test body described above. The battery cells to be tested have an interior space enclosed by an outer shell, wherein the interior space contains a liquid electrolyte solution. The testing system has at least one leak testing device for testing the tightness of the outer shell. The leak testing device has a sensor device configured to detect one or more, in particular gaseous, constituents of the electrolyte solution in an environment outside the outer shell of the battery cells to be tested. The test body can be introduced into the testing system instead of a battery cell to be tested.

[0030] The statements regarding the above-described test body and its advantageous developments apply accordingly to the system according to the invention, and vice versa. The same applies to the method and system according to the invention.

[0031] The following figures illustrate the invention in more detail using exemplary embodiments without being limited to them. They show: Fig. 1 a test system for testing battery cells in a schematic representation, Fig. 2 a battery cell designed as a pouch cell in a schematic representation in a view according to the arrow II in Fig. 3, Fig. 3 the battery cell in a schematic representation in a view according to the arrow III in Fig. 2, Fig. 4 the battery cell in a schematic representation in a sectional view according to the line IV-IV in Fig. 2, Fig. 5 a test body with an outer shape of the pouch cell in a schematic representation in a view according to the arrow V in Fig. 6, Fig. 6 the test body in a schematic representation in a view according to the arrow VI in Fig. 5, Fig. 7 the test body in a schematic representation in a sectional view according to the arrow VII-VII in Fig. 5, Fig. 8 the test body in a schematic representation in a view according to the line VIII-VIII in Fig. 6, Fig. 9 a test body with an outer shape of a prismatic battery cell in a schematic representation in a side view, Fig. 10 a test body with an outer shape of a round cell in a schematic representation in a side view.

[0032] The Fig. Figure 1 shows a schematic representation of a test system 20 for testing battery cells 10, in this case lithium-ion cells. The battery cells 10 are pouch cells, also referred to as coffee bag cells.

[0033] The battery cells 10 to be tested have an interior space 13 enclosed by an outer shell 12. This interior space 13 contains an electrode arrangement 14, which is also filled with a liquid electrolyte solution 15 containing dimethyl carbonate (DMC). The electrode arrangement 14 comprises several cathode layers and several anode layers. The cathode layers are electrically connected to a first cell terminal 16, and the anode layers are electrically connected to a second cell terminal 17, as can be seen from the sectional view of the Fig. 4 can be seen.

[0034] The test system 20 has several testing devices. In this case, the test system 20 comprises a voltage testing device 21, an insulation testing device 22, and a leak testing device 23. The voltage testing device 21 has a measuring device 210 with a first measuring contact 211 for contacting the first cell terminal 16 of the battery cell 10 to be tested and with a second measuring contact 212 for contacting the second cell terminal 17 of the battery cell 10 to be tested. The measuring device 210 is configured to measure an open current voltage (OCV) between the first cell terminal 16 and the second cell terminal 17.

[0035] The insulation testing device 22 comprises a further measuring device 220 with a further first measuring contact 221 and a further second measuring contact 222 for contacting the outer shell 12 of the battery cell 10 with the further first measuring contact 221 and the second cell terminal 17 of the battery cell 10 with the further second measuring contact 222.

[0036] The leak testing device 23 serves to test the leak tightness of the outer shell 12. For this purpose, the leak testing device 23 has a sensor device 230. The sensor device 230 is configured to detect one or more components, particularly those present in gaseous form, of the electrolyte solution 15 in an environment or atmosphere outside the outer shell 12 of the battery cell 10 to be tested.

[0037] The testing system 20 further comprises two transport devices 24, wherein the transport devices 24 are configured to transport the battery cells 10 to be tested from one of the testing devices to the subsequent testing device. The respective transport device 24 can, for example, have a gripper for gripping the battery cell 10 at its outer shell 12, wherein the gripper is attached to a robot arm.

[0038] In order to test the test system 20, in particular the leak test device 23, for its correct function, the Fig. 5 to 8 can be used instead of a battery cell 10 in the test system 20. This test body 30 is designed with its external shape to correspond to the battery cells 10 to be tested. Accordingly, the test body 30 can be introduced into the test system 20 instead of a battery cell 10 and can also be handled by the transport devices 24 like a battery cell 10.

[0039] The test body 30 has a gas release device 40. The gas release device 40 has a receiving device 41 for receiving a test liquid. In this case, this test liquid is the liquid electrolyte solution 15. The gas release device 40 is designed such that when the electrolyte solution 15 held in the receiving device 41 evaporates or evaporates, the gases 43 produced during the evaporation or evaporation reach the environment outside the test body 30. If the test body 30 is now arranged in the leak testing device 23, the resulting gases 43 reach the detection range of the sensor device 230 and, if the sensor device 230 is functioning correctly, are detected by the sensor device 230. As a result, the leak testing device 23 evaluates the test body 30 as a defective battery cell 10.The leak testing device 23 can have an ejection device that ejects a battery cell 10 from the testing system upon detection of a defective battery cell 10. The same would also be done for the test body 30. If the sensor device 230 does not detect the gases 43 emitted by the test body, it can be concluded that the sensor device 230 is defective and thus that the leak testing device 23 is not functioning correctly.

[0040] In this case, the test body 30 has a housing 32, wherein an outer contour of the housing 32 corresponds to the outer shape of the battery cells 10 to be tested. The housing 32 can be flexible, especially if the battery cells 10 to be tested are pouch cells. However, it can also be rigid, especially if the battery cells 10 to be tested are prismatic cells.

[0041] As can be seen in particular from the sectional view of the Fig. As can be seen from Figure 8, the receiving device 41 has a receiving space 42, wherein a carrier body 45 is arranged in the receiving space 42. The carrier body 45 in this case consists of an absorbent material, for example a foam, wherein the carrier body 45 is impregnated with the electrolyte solution 15. The gas discharge device 40 has a heating device 44, wherein the heating device 44 is configured to heat the electrolyte solution 15 received in the receiving device 41 in order to evaporate the electrolyte solution 15. The heating device 44 is formed below the carrier body 45.

[0042] The gas release device 40 is presently formed within the housing 32, wherein the housing 32 has three through-openings 46 in the region of the gas release device 40, namely above the carrier body 45. The gases 43 produced during the evaporation of the electrolyte solution 15 can escape from the test body 30 into the environment via these through-openings 46, as shown schematically in the Fig. 8, and thus reach the sensor device 230.

[0043] The test body 30 further comprises a voltage source 50 and a first contacting element 51 and a second contacting element 52, wherein the first and second contacting elements 51, 52 are connected to the voltage source 50. The contacting elements 51, 52 are arranged on the outside of the carrier body 30, wherein the position and design of the contacting elements 51, 52 correspond to those of the cell terminals 16, 17 in a battery cell 10 to be tested, so that the measuring contacts 211, 212 of the measuring device 210 would contact the contacting elements 51, 52 when testing the open-circuit voltage if the test body 30 is arranged in the voltage testing device 21 instead of a battery cell 10. The voltage source 50 of the test body 30 is designed to provide an open-circuit voltage between the contacting elements 51, 52 which corresponds to the open-circuit voltage of a proper battery cell 10 to be tested.The voltage source 50 can, for example, be a capacitor.

[0044] By using a test body 30 instead of a battery cell 10, testing of the aforementioned three test devices, namely the voltage test device 21, the insulation test device 22, and the leak test device 23, can be performed during ongoing operation of the test system 20. This eliminates the need to stop the operation of the test system 20 for testing or to simply insert and remove a test body 30 from one of the aforementioned test devices for the purpose of testing this test device.

[0045] The Fig. 9 shows a second embodiment of the test body 30. This second embodiment differs from the embodiment according to the Fig. 5 to 8 essentially by its external shape. In the second embodiment, the external shape corresponds to that of a prismatic battery cell 10.

[0046] The Fig. Figure 10 shows a third embodiment of the test body 30. This third embodiment differs from the embodiment according to the Fig. 5 to 8 essentially by its external shape. In the third embodiment, the external shape corresponds to that of a round cell. List of reference symbols 10 battery cells 12 Outer shell 13 Interior 14 electrode stacks 15 Electrolyte solution 16 first cell terminal 17 second cell terminal 20 test system 21 Voltage testing device 22 Insulation testing device 23 Leak testing device 24 Transport device 30 test specimens 32 housings 40 Gas discharge device 41 Recording facility 42 Recording Room 44 Heating device 45 carrier bodies 50 voltage source 51 first contacting element 52 second contacting element 210 Measuring device 211 first measuring contact 212 second measuring contact 220 additional measuring devices 221 further first measuring contact 221 222 further second measuring contact 222 230 Sensor device

Claims

[1] Test body (30) for testing a test system (20) for testing battery cells (10), wherein the battery cells (10) to be tested have an interior space (13) enclosed by an outer shell (12), wherein the interior space (13) contains a liquid electrolyte solution (15), wherein the test system (20) has at least one leak testing device (23) for testing the tightness of the outer shell (12), wherein the leak testing device (23) has a sensor device (230) which is designed to detect one or more components of the electrolyte solution (15) in an environment outside the outer shell (12) of the battery cells (10) to be tested, wherein the test body (30) is designed such that the test body (30) can be introduced into the test system (20) instead of a battery cell (10), wherein the test body (30) has: - a gas release device (40), wherein the gas release device (40) has a receiving device (41) for receiving a test liquid, wherein the test liquid comprises the liquid electrolyte solution (15) or the one or more components of the electrolyte solution (15) that can be detected by the sensor device (230), wherein the gas release device (40) is designed such that when the test liquid received in the receiving device (41) evaporates or evaporates, the gases (43) produced during the evaporation or evaporation reach the environment outside the test body (30) characterized byin that the test body (30) has a voltage source (50) and one or more external contacting elements (51, 52), wherein the one or more contacting elements (51, 52) are connected to the voltage source (50), wherein the voltage source (50) is designed to provide an open-circuit voltage at the one or more contacting elements (51, 52) which corresponds to the open-circuit voltage of the battery cells (10) to be tested. [2] Test body (30) according to claim 1, wherein the test body (30) has a housing (32), wherein an outer contour of the housing (32) corresponds to an outer shape of the battery cells (10) to be tested. [3] Test body (30) according to claim 1 or 2, wherein the gas discharge device (40) has a heating device (44), wherein the heating device (44) is adapted to heat the test liquid received in the receiving device (41) to evaporate the test liquid. [4] Test body (30) according to one of claims 1 to 3, wherein the receiving device (41) has a receiving space (42), wherein a carrier body (45) made of an absorbent material is received in the receiving space (42), wherein the carrier body (45) can be impregnated with the test liquid. [5] Test body (30) according to claim 4, wherein the carrier body (45) is replaceable. [6] Test body (30) according to claim 2 or according to claim 2 and one of claims 3 to 5, wherein the gas discharge device (40) is formed within the housing (32), wherein the housing (32) in the region of the gas discharge device (40) or a cover of the gas discharge device (40) has one or more through openings (46), wherein the gases (43) pass through the one or more through openings (46) into the environment outside the test body (30). [7] A method for testing a test system (20) for testing battery cells (10), wherein the battery cells (10) to be tested have an interior space (13) enclosed by an outer shell (12), wherein the interior space (13) contains a liquid electrolyte solution (15), wherein the test system (20) has at least one leak testing device (23) for testing the tightness of the outer shell (12), wherein the leak testing device (23) has a sensor device (230) which is designed to detect one or more components of the electrolyte solution (15) in an environment outside the outer shell (12) of the battery cells (10) to be tested, wherein the method is carried out using a test body (30) according to one of the preceding claims, wherein the method comprises: - introducing the test liquid into the receiving device (41) of the gas discharge device (40) of the test body (30), - Inserting the test body (30) into the leak testing device (23) instead of a battery cell (10). [8] Method according to claim 7, wherein the testing system (20) has at least one further testing device and a transport device (24), wherein the transport device (24) is designed to transport a battery cell (10) introduced into the testing system (20) from the further testing device to the leak testing device (23) or to transport it from the leak testing device (23) to the further testing device, wherein the test body (30) is designed such that the transport device (24) transports the test body (30) instead of a battery cell (10). [9] System, a testing system (20) for testing battery cells (10) and comprising a test body (30) according to one of claims 1 to 6, wherein the battery cells (10) to be tested have an interior space (13) enclosed by an outer shell (12), wherein the interior space (13) contains a liquid electrolyte solution (15), wherein the testing system (20) has at least one leak testing device (23) for testing a leak tightness of the outer shell (12), wherein the leak testing device (23) has a sensor device (230) which is designed to detect one or more components of the electrolyte solution (15) in an environment outside the outer shell (12) of the battery cells (10) to be tested, wherein the test body (30) can be introduced into the testing system (20) instead of a battery cell (10) to be tested.

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