Test circuit, test device and test tool

Abstract

The application discloses a test circuit, a test device and a test tool, and relates to the technical field of battery testing, wherein the test circuit comprises a first test loop, a second test loop, an isolation module, a switching module and a control module; the first test loop is used for connecting a first test module and each to-be-tested component respectively; the second test loop has a first line and a second line, and the isolation module is arranged in series in the second line; in a first mode, the first test module is connected to each to-be-tested component through the first test loop; in a second mode, the first line is connected to each to-be-tested component through the first test loop; the control module controls the isolation module to be in an isolation state and the switching module to work in the first mode in response to a high-voltage test instruction, and controls the isolation module to be in a conduction state and the switching module to work in the second mode in response to a low-voltage test instruction. The application aims to optimize the topological design of the test circuit, so as to reduce the redundancy of the hardware structure.

Description

Technical Field

[0001] This application relates to the field of battery testing technology, and in particular to a test circuit, test device and test fixture. Background Technology

[0002] Some test circuits, especially those used to test the insulation resistance between battery modules, have complex circuit designs and require a large number of high-voltage relays, high-voltage silicone wires, and detection probes, resulting in redundancy in the overall hardware structure. Summary of the Invention

[0003] The main objective of this application is to provide a test circuit, test device, and test fixture, which aims to optimize the topology design of the test circuit to reduce redundancy in the hardware structure.

[0004] To achieve the above objectives, in a first aspect, this application proposes a test circuit for testing multiple devices under test (DUTs). The test circuit includes a first test circuit, a second test circuit, an isolation module, a switching module, and a control module. The first test circuit connects the first test module and each DUT. The second test circuit has a first line and a second line. The first end of the first line connects to the first test terminal of the second test module, and the second end of the first line connects to each DUT through the first test circuit. The first end of the second line connects to the second test terminal of the second test module, and the second end of the second line connects to each DUT. The switching module can switch between a first mode and a second mode. In the first mode, the first test module connects to each DUT through the first test circuit, and the first line is disconnected from each DUT. In the second mode, the first test module is disconnected from each DUT, and the first line connects to each DUT through the first test circuit. The isolation module is connected in series in the second line and can switch between a conducting state and an isolated state.

[0005] It is understood that the test circuit in this embodiment, through the switching module and the topology design of the first and second test circuits, allows the second test circuit to reuse the first test circuit, achieving path multiplexing of the low-voltage test signal to the high-voltage main transmission channel and avoiding the resource waste caused by independent high- and low-voltage wiring. Simultaneously, the introduction of a mechanically based isolation module utilizes the physical separation of probes and contacts to construct an air insulation barrier, directly replacing the high-voltage relays that must be connected in series on each acquisition channel in the prior art to protect low-voltage instruments. Therefore, this test circuit reduces the number of hardware components and optimizes the overall wiring space, thereby reducing structural redundancy in the test circuit.

[0006] In some embodiments, the plurality of test devices (DDTs) include a plurality of first DDTs and a plurality of second DDTs arranged in an alternating manner; the first test circuit has a third line and a fourth line, the first end of the third line is used to connect to the positive test terminal of the first test module, and the second end of the third line is used to connect to the plurality of first DDTs; the first end of the fourth line is used to connect to the negative test terminal of the first test module, and the second end of the fourth line is used to connect to the plurality of second DDTs; the second end of the first line is used to connect to each of the first DDTs through the third line, and to connect to each of the second DDTs through the fourth line; in a first mode, the switching module connects the positive test terminal of the first test module to the first polarity terminal of the plurality of first DDTs through the third line, and connects the negative test terminal of the first test module to the second polarity terminal of the plurality of second DDTs through the fourth line, and disconnects the first line from each of the first DDTs and each of the second DDTs; in a second mode, the first test module is disconnected from each of the first DDTs and each of the second DDTs, and the first line connects to each of the first DDTs through the third line or connects to each of the second DDTs through the fourth line.

[0007] Understandably, by utilizing a topology combining interleaved grouping and line multiplexing, the insulation performance between various devices under test (DUTs) can be tested through a single high-voltage load, improving testing efficiency. Furthermore, by controlling the switching module, low-voltage test signals can be transmitted via the high-voltage transmission trunk line, eliminating the need for a separate, complex low-voltage acquisition harness for the large battery array. This simplifies wiring, reduces the number of relays used, and ultimately reduces structural redundancy in the test circuitry.

[0008] In one embodiment, the second end of the third line is used to connect to the first polarity end of a plurality of first test devices, and the second end of the fourth line is used to connect to the second polarity end of a plurality of second test devices, wherein one of the first polarity end and the second polarity end is a positive electrode and the other is a negative electrode.

[0009] Understandably, by creating a voltage gradient between adjacent test pieces to break the equipotential state, this embodiment can excite minute insulation defects into testable leakage currents, thereby effectively eliminating the blind spots that may be caused by same-polarity testing.

[0010] In some embodiments, the second end of the second line is used to connect the first polarity terminal of each first device under test and the second polarity terminal of each second device under test, respectively.

[0011] It is understood that the contact test in this embodiment is performed only on a single pole, and the test circuit is always at the same potential, with no voltage difference. Since no cross-polarity connection is involved, a short circuit cannot be physically formed. In this way, the risk of short circuit is eliminated at the source, providing a safety guarantee.

[0012] In some embodiments, in the first mode, the first test terminal of the first test module is connected to the first device under test (DUT) via the third line, and the second test terminal of the first test module is connected to the second DUT via the fourth line, while the first line is disconnected from each DUT. The second mode includes a first execution segment and a second execution segment. In the first execution segment, the first test module is disconnected from each DUT, and the first line is connected to the first polarity terminal of each first DUT via the third line. In the second execution segment, the first test module is disconnected from each DUT, and the first line is connected to the second polarity terminal of each second DUT via the fourth line.

[0013] It is understandable that this embodiment achieves low-voltage testing for single-pole devices by subdividing the low-voltage test mode into independent execution segments for different groups of devices under test, and reuses the transmission path of the first test circuit. In this way, the low-voltage detection signal can be transmitted in segments using the existing high-voltage transmission trunk line, without the need to lay separate low-voltage acquisition lines for multiple devices under test, thus reducing the redundancy of the hardware structure and the complexity of wiring.

[0014] In some embodiments, the test circuit further includes a control module configured to: in response to the low-voltage test command, control the isolation module to be in a conducting state and control the switching module to operate in the first execution segment and the second execution segment respectively; in response to the high-voltage test command, control the isolation module to be in an isolated state and control the switching module to operate in the first mode.

[0015] Understandably, the control module can control the switching module and the isolation module to switch between each other. In response to the low-voltage test command, the control module determines the connection continuity between each of the first test devices and the third line, and the connection continuity between each of the second test devices and the fourth line. In response to the high-voltage test command, the control module determines the insulation resistance between each pair of adjacent test devices through the first test module, thus realizing automatic detection.

[0016] In some embodiments, the first test circuit further includes a fifth line, one end of which is connected to the second test terminal of the first test module, and the other end of which is used to connect to the packaging shell of a plurality of devices under test.

[0017] Understandably, this fifth line allows for testing of the insulation resistance between all charged cells as a whole and the packaged casing, thereby eliminating the possibility of short circuits to ground or damage to the insulation layer inside the module in one go.

[0018] In some embodiments, the switching module can switch between a first mode, a second mode, and a third mode. In the first mode, the first test terminal of the first test module is connected to the first device under test (DUT) via the third line, and the second test terminal of the first test module is connected to the second DUT via the fourth line. The first line is disconnected from each DUT. The second mode includes a first execution segment and a second execution segment. In the first execution segment, the first test module is disconnected from each DUT, and the first line is connected to the first polarity terminal of each first DUT via the third line. In the second execution segment, the first test module is disconnected from each DUT, and the first line is connected to the second polarity terminal of each second DUT via the fourth line. In the third mode, the first terminal of the fourth line is connected to the third line, the first test terminal of the first test module is connected to each DUT via the third and fourth lines, the fifth line is connected to the second test terminal of the first test module, and the first line is disconnected from each DUT.

[0019] Understandably, during the switching operation of the switching module, the second test circuit and the fifth line can be connected to each device under test (DUT) through the first test circuit. In this way, line reuse simplifies the structural redundancy of the test circuit, achieving efficient and reliable automated testing.

[0020] In some embodiments, the test circuit further includes a control module, which is further configured to: in response to the low-voltage test command, control the isolation module to be in a conducting state and control the switching module to operate in the first execution segment and the second execution segment respectively; in response to the first high-voltage test command, control the isolation module to be in an isolated state and control the switching module to operate in the first mode; and in response to the second high-voltage test command, control the isolation module to be in an isolated state and control the switching module to operate in the third mode.

[0021] Understandably, the control module can control the switching module and the isolation module to switch between each other. In response to the low-voltage test command, the control module determines the connection continuity between each of the first devices under test (DUTs) and the third line, and the connection continuity between each of the second DUTs and the fourth line. Furthermore, in response to the first high-voltage test command, the control module determines the insulation resistance between each pair of adjacent DUTs through the first test module, thus achieving automatic detection. Additionally, in response to the second high-voltage test command, the control module determines the insulation resistance between each DUT and the package housing through the first test module, thus achieving automatic detection.

[0022] In some embodiments, the switching module includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch; the first switch is connected in series in the third circuit, with a first end for connecting to the positive test terminal of the first test module and a second end for connecting to the first polarity terminals of a plurality of first test devices; the second switch is connected in series in the fourth circuit, with a first end for connecting to the negative test terminal of the first test module and a second end for connecting to the second polarity terminals of a plurality of second test devices; the third switch is connected between the second ends of the first switch and the second ends of the second switch; the fourth switch is connected between the first circuit and the first end of the first switch; the fifth switch is connected between the first circuit and the first end of the second switch; and the sixth switch is connected in series in the fifth circuit.

[0023] It is understandable that this embodiment achieves the switching of three different circuit configurations on the same physical wiring harness through a specific connection combination of six switches. Compared to the existing test circuits that require more than three hundred relays, this solution uses only six relays, which greatly simplifies the hardware wiring and hardware requirements of the test circuit and reduces the redundancy of the hardware structure.

[0024] In some embodiments, the isolation module includes a driving unit, a first connection module, and a second connection module. The first connection module and the second connection module are connected in series on the second line. The driving unit is driven to at least one of the first connection module and the second connection module. The driving unit is configured to: drive the first connection module and the second connection module to abut against each other to conduct the second line; and drive the first connection module and the second connection module to separate from each other to disconnect the second line.

[0025] In some embodiments, the first connection module has a plurality of first electrical connectors, and the second connection module has a plurality of second electrical connectors; the first ends of the plurality of first electrical connectors are used to connect one-to-one with a plurality of devices under test, the second ends of the plurality of first electrical connectors are used to connect one-to-one with the first ends of the plurality of second electrical connectors, and the second ends of the plurality of second electrical connectors are used to connect to the second test terminal of the second test module; the driving unit is capable of driving the plurality of first electrical connectors and the plurality of second electrical connectors to connect one-to-one, entering a conduction state to conduct the second line; and is capable of driving the plurality of first electrical connectors and the plurality of second electrical connectors to move away from each other, entering an isolation state to disconnect the second line.

[0026] Understandably, by using isolation modules, the use of relays can be reduced. This not only reduces the material cost and PCB wiring space of the system and the structural redundancy of the test circuit, but also completely eliminates the risk of high-voltage breakdown that may be caused by oxidation or adhesion of relay contacts.

[0027] Secondly, this application also provides a testing device, which includes the testing circuit described above.

[0028] In some embodiments, the testing apparatus further includes a probe module, which has a first probe group and a second probe group, each having a plurality of test probes; the first ends of the plurality of test probes in the first probe group are used to connect to the first test circuit, and the second ends of the plurality of test probes in the first probe group are used to connect one-to-one with a plurality of devices under test; the first ends of the plurality of test probes in the second probe group are used to connect to the isolation module, and the second ends of the plurality of test probes in the second probe group are used to connect one-to-one with a plurality of devices under test.

[0029] It is understood that this embodiment constructs a high-pressure loading channel and a low-pressure sampling channel by configuring independent first probe groups and second probe groups respectively.

[0030] In some embodiments, the testing apparatus further includes a parallel module connected between the first test circuit and the first probe group; the parallel module is used to connect the first ends of each test probe in the first probe group to the first test circuit in parallel.

[0031] Understandably, by connecting the probe modules in parallel, the testing device does not need to run hundreds of high-voltage cables from the control cabinet to connect each probe separately. Instead, it only needs to run the main line to connect to the parallel module.

[0032] Thirdly, this application also provides a test fixture, which includes the test circuit as described above, or the test device as described above. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 A schematic diagram of a first embodiment of the test circuit provided in this application;

[0035] Figure 2 A schematic diagram of a second embodiment of the test circuit provided in this application;

[0036] Figure 3 A schematic diagram of a third embodiment of the test circuit provided in this application;

[0037] Figure 4 A schematic diagram of a fourth embodiment of the test circuit provided in this application;

[0038] Figure 5 A schematic diagram of the fifth embodiment of the test circuit provided in this application;

[0039] Figure 6 This is a schematic diagram of the first embodiment of the test fixture provided in this application.

[0040] Explanation of icon numbers:

[0041] 10. Test circuit; 100. First test loop; 110. Third line; 120. Fourth line; 130. Fifth line; 200. Second test loop; 210. First line; 220. Second line; 300. Isolation module; 310. Drive unit; 320. First connection module; 330. Second connection module; 400. Switching module; 500. Control module; 20. Device under test; 21. First device under test; 22. Second device under test; 31. First test module; 32. Second test module; 41. Encapsulation shell; 50. Test fixture; 60. Parallel module;

[0042] K1, First switch; K2, Second switch; K3, Third switch; K4, Fourth switch; K5, Fifth switch; K6, Sixth switch; K7, Seventh switch; K8, Eighth switch.

[0043] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0046] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more (including two), unless otherwise explicitly defined.

[0047] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0049] With the rapid development of electric vehicles, power tools, drones, and energy storage devices, battery modules, as one of the core components of these devices, are seeing their application scenarios continuously expand. Battery modules consist of multiple battery cells arranged and fixed together, providing higher energy density and more stable performance to meet the needs of various applications.

[0050] In some embodiments, battery modules can be applied to electric vehicles such as electric bicycles, electric motorcycles, and electric cars. A battery module integrates multiple battery cells into a unified energy source to power the vehicle. This increases the overall energy density of the battery, simplifies the design and maintenance of the battery management system (BMS), and improves the vehicle's range and safety.

[0051] In some embodiments, battery modules can be used in portable devices such as power tools and drones. Due to their high energy density and small size, battery modules are ideal for applications requiring high power output and long operating times. For example, in power tools, battery modules can provide continuous and stable power, ensuring efficient operation in various working environments; in drones, battery modules can provide sufficient flight time and payload capacity to meet diverse needs such as aerial photography and logistics delivery.

[0052] In some embodiments, battery modules can be integrated into energy storage devices, such as energy storage containers or energy storage cabinets. Energy storage devices are commonly used in grid energy storage, distributed energy storage, and emergency power supplies. Through modular design, battery modules can be flexibly configured with capacity according to actual needs, meeting energy storage requirements of different scales. Furthermore, battery modules can be combined with renewable energy systems such as solar and wind power to achieve the effective storage and utilization of clean energy.

[0053] In some embodiments, the battery module can be integrated into the vehicle chassis structure. For example, a portion of the battery module can be part of the vehicle's floor, crossbeams, or longitudinal beams, thereby optimizing the vehicle's space utilization and overall structural strength. This design not only improves the vehicle's safety and stability but also reduces the need for additional installation space, further enhancing the overall performance of the vehicle.

[0054] In some embodiments, the battery cells in the battery module can be of various types, including but not limited to lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc. The specific shape of the battery cells can also vary, such as cylindrical battery cells, prismatic battery cells, pouch battery cells, or other shapes of battery cells. For example, a prismatic battery cell can be a prismatic battery cell, a blade-shaped battery cell, or a multi-prism battery (such as a hexagonal prism battery) to meet different application requirements.

[0055] In summary, battery modules, with their flexibility, high efficiency, and reliability, are widely used in electric vehicles, portable devices, energy storage devices, and other fields, driving technological progress and development across various industries. Through continuous optimization of battery module design and manufacturing processes, their performance and application scope will be further improved in the future to meet the growing market demand.

[0056] It is important to note that battery modules typically integrate a large number of cells. To ensure the safety of battery modules in the aforementioned high-voltage, high-energy-density application scenarios, the reliability of electrical connections and insulation performance within the battery module must be tested. For example, multiple cells are usually closely arranged, requiring testing of the insulation resistance between each adjacent cell or cell group to prevent short circuits or thermal runaway caused by internal insulation failure. Simultaneously, battery modules typically have a metal enclosure, such as an aluminum alloy case or tray. To prevent leakage accidents and ensure user safety, the insulation resistance and withstand voltage performance between each cell and the enclosure must also be tested individually. Furthermore, before conducting the aforementioned high-voltage tests, a low-voltage test is usually required to check the contact connection between the test probes and the cell terminals to prevent misjudgments or no-load testing due to loose probe connections or poor contact.

[0057] However, existing test circuits are complex, and their hardware architecture suffers from significant redundancy. According to current technical solutions, to accommodate both low-voltage contact testing and high-voltage insulation testing within the same test circuit, the test loop is typically designed with a shared measurement channel for both high and low voltage. This necessitates the use of a large number of relays for signal isolation and function switching. For example, a test circuit for a battery module requires more than 360 relays and a large number of test probes, with the accompanying high-voltage silicone wiring harnesses reaching lengths of several kilometers, resulting in overall hardware redundancy.

[0058] For the test circuits mentioned above that require a large number of relays, the specific topology is as follows: each polarity terminal of each device under test (i.e., each probe channel) must be connected in series with at least one independent high-voltage relay. The signal lines of all probes converge to a common test bus via these relays, and then are switched via the bus to either a low-voltage acquisition instrument or a high-voltage test module. Since high-voltage insulation testing and low-voltage contact detection share the same physical transmission line, in order to physically disconnect the low-voltage instrument's path during high-voltage testing to prevent breakdown, and simultaneously to achieve individual selection of hundreds or thousands of cells during low-voltage testing, the system is forced to deploy high-voltage relays at each sampling node. This single-point, single-control topology results in a rigid proportional relationship between the number of relays and the number of probes (for example, 360 probes require more than 360 relays).

[0059] Therefore, in order to reduce the structural redundancy of the test circuit 10, this application proposes a test circuit 10, in one embodiment, such as... Figure 1 As shown, the test circuit 10 includes a first test loop 100, a second test loop 200, an isolation module 300, and a switching module 400.

[0060] This test circuit 10 is used to test multiple devices under test (DUTs) 20. The specific form of the DUT 20 can be flexibly adjusted according to actual testing needs; it can be a single cell or a battery pack consisting of multiple cells connected in series and parallel. It is understood that when the DUT 20 is a single cell, this test circuit 10 can test the insulation resistance between every two adjacent cells through the first test loop 100; when the DUT 20 consists of multiple cells, this test circuit 10 can test the insulation resistance between every two adjacent battery packs. Of course, the DUT 20 can also be other types of energy storage elements or power generation components besides cells, such as supercapacitors, fuel cell stacks, and photovoltaic modules; specific details are not limited here.

[0061] In this embodiment, as Figure 1 As shown, the test circuit includes a first test circuit 100 and a second test circuit 200. The first test circuit 100 is used to connect the first test module 31 and each device under test 20, respectively. The second test circuit 200 has a first line 210 and a second line 220. The first end of the first line 210 is used to connect to the first test terminal of the second test module 32, and the second end of the first line 210 is used to connect to each device under test 20 through the first test circuit 100. The first end of the second line 220 is used to connect to the second test terminal of the second test module 32, and the second end of the second line 220 is used to connect to each device under test 20.

[0062] It is understood that the connection in this embodiment can be made through a switch in electrical terms; that is, the connection in this embodiment can represent two situations: the line is not connected (switch is on) or the line is connected (switch is closed).

[0063] In the second test circuit 200, one of the first test terminal and the second test terminal is the positive terminal, and the other is the negative terminal.

[0064] Optionally, the first test module 31 is configured as a high-voltage test module, such as an insulation withstand voltage tester, for outputting a high-voltage signal to perform insulation performance testing; the second test module 32 is specifically configured as a low-voltage test module, such as a multi-channel resistance tester, for outputting a low-voltage / low-current signal to perform continuity or contact resistance testing.

[0065] The first test circuit 100 and the first test module 31 are configured to perform high-voltage tests, while the second test circuit 200 and the second test module 32 are configured to perform low-voltage tests. Further details will not be provided below.

[0066] The first test circuit 100 forms the transmission channel between the first test module 31 and each device under test (DUT) 20. Both ends of the first test circuit 100 are directly connected to the output of the first test module 31 and each DUT 20, respectively. In high-voltage test mode, the first test circuit 100 undertakes the task of transmitting high-voltage signals, ensuring that the first test module 31 can directly apply high voltage to each DUT 20, thus forming a complete high-voltage test circuit. The second test circuit 200 can be understood as employing a multiplexed connection architecture, specifically composed of a first line 210 and a second line 220. The first line 210 connects the second test module 32 and the first test circuit 100, and is configured to indirectly access each DUT 20 through the first test circuit 100. This means that the first line 210 utilizes the existing cable of the first test circuit 100 as a transmission medium to inject low-voltage signals into the DUT 20 side. The second line 220 itself is independently connected to each DUT 20, serving as a return path for low-voltage signals and ensuring the closure of the low-voltage test circuit. Thus, this test circuit 10 can perform various testing functions by utilizing the cooperation of the first test circuit 100 and the second line 220 without adding extra probes and wiring harnesses. For example, it can perform high-voltage insulation testing as well as low-voltage line continuity testing or probe contact resistance testing, achieving an organic integration of high and low voltage testing functions and maximizing the utilization of line resources.

[0067] In this embodiment, as Figure 1 As shown, the isolation module 300 is connected in series in the second line 220 and has both a conducting state and an isolated state.

[0068] The isolation module 300 is configured as a mechanically driven physical connection and separation device. This isolation module 300 can consist of a drive unit 310 (such as a cylinder, linear motor, or electric actuator), and probe modules and contact modules connected in series in the second circuit 220. Its working principle is to control the circuit's on / off state using mechanical displacement: when the drive unit 310 initiates the connection between the probe module and the contact module, they form a physical contact and establish electrical continuity, thereby connecting the second circuit 220. This allows the second test terminal of the second test module 32 to connect with each device under test (DUT) 20, putting the system in a conductive state for low-voltage testing. When the drive unit 310 drives the two modules to separate, a physical air gap is formed between the probe module and the contact module, thereby cutting off the second circuit 220 and putting the system in an isolated state. Air insulation is used to block the high-voltage signal from the first test circuit 100 from entering the second test module 32.

[0069] Optionally, the isolation module 300 also has a parallel bus function. For example, the probe module is positioned close to the second test module 32, and the contact module is positioned close to each device under test (DUT) 20. In this case, the contact module can be designed as a busbar or a PCB board with internal conductive lines. It has multiple discrete contact terminals on the side facing the DUT 20, each connected one-to-one to one of the DUTs 20. These discrete contact terminals are short-circuited and busbed within the contact module. Thus, when the probe module comes into contact with the contact module, it can be understood as physically connecting the polarity terminals of multiple DUTs 20 in parallel, and then uniformly connecting them to the second test module 32 through the second line 220. This eliminates the need for additional wires to connect the DUTs 20 in parallel; instead, the parallel bus function is directly achieved using the contact module of the isolation module 300, greatly simplifying the wiring structure of the test circuit 10.

[0070] It is understandable that the isolation module 300 can reduce or even completely eliminate the use of high-voltage relays in the low-voltage acquisition circuit. In existing solutions, to prevent signal backflow during high-voltage insulation testing from damaging the low-voltage resistance tester, a high-voltage relay is typically connected in series on each low-voltage acquisition line connecting the device under test (DUT) 20. For example, for a large battery module containing hundreds of cells (DUT 20), this means hundreds of relays are required, resulting in extremely high hardware costs and complex control logic. In this embodiment, the air gap created by the mechanical action of the isolation module 300 directly replaces the contact disconnection function of the traditional relay. This not only reduces the material cost and PCB wiring space of the system and reduces the structural redundancy of the test circuit 10, but also completely eliminates the risk of high-voltage breakdown caused by relay contact oxidation or adhesion.

[0071] In this embodiment, the switching module 400 can switch between a first mode and a second mode. In the first mode, the first test module 31 connects each device under test 20 through the first test circuit 100, and the first line 210 is disconnected from each device under test 20. In the second mode, the first test module 31 is disconnected from each device under test 20, and the first line 210 connects each device under test 20 through the first test circuit 100.

[0072] Understandably, in the first mode, the switching module 400 connects the main path of the first test circuit 100, allowing the high-voltage signal output by the first test module 31 to be applied to each device under test (DUT) 20. Importantly, at this time, the switching module 400 disconnects the first line 210 from the first test circuit 100, effectively blocking the path of the high-voltage signal to the second test module 32, thus protecting the second test module 32 from high-voltage breakdown. In the second mode, the switching module 400, on the one hand, cuts off the high-voltage output path of the first test module 31, and on the other hand, connects the first line 210 to each DUT 20 at one end of the first test circuit 100. Through this switching module 400, the low-voltage test signal output by the second test module 32 can be injected into the first test circuit 100 via the first line 210, and reach each DUT 20 along the high-voltage cable of the first test circuit 100, simplifying wiring and avoiding the need to lay separate wiring for each DUT 20.

[0073] Optionally, the switching module 400 can be implemented using relays. Unlike existing distributed control schemes that connect relays in series on each test channel, this embodiment employs centralized line switching logic. A few relays are sufficient to control the entire test circuit's mode switching between high-voltage and low-voltage testing, and a mechanical isolation module 300 completes the specific channel selection. In other words, the high-low voltage isolation and channel switching tasks that originally required a large number of relays can now be accomplished with only a few relays to achieve bus-level path switching.

[0074] Optionally, this test circuit may further include a control module 500, which is configured to, in response to a high-voltage test command, control the isolation module 300 to be in an isolated state and control the switching module 400 to operate in a first mode; and, in response to a low-voltage test command, control the isolation module 300 to be in a conducting state and control the switching module 400 to operate in a second mode. The high-voltage test command corresponds to the insulation test procedure between each device under test (DUT) 20. This high-voltage test command aims to control the first test module 31 to apply a high-voltage test signal to each DUT 20 through the first test circuit 100 to test the insulation resistance between every two adjacent DUTs or a specific number of DUTs, thereby determining whether there is a short circuit or insulation failure between each DUT 20; simultaneously, it controls the isolation module 300 to be in an isolated state to prevent the high-voltage signal from entering the second test circuit 200 by physically disconnecting it. The low-voltage test command corresponds to testing the continuity of the connection between each device under test (DUT) 20 and the first test loop 100. At this time, the second test module 32 outputs a test signal and, using the continuity status of the isolation module 300, tests the resistance or continuity of the loops formed by the first line 210 and the second line 220 and each DUT 20. This determines whether the physical connection between the test circuit 10 and each DUT 20 is in place, ensuring the accuracy of subsequent high-voltage tests. The first test module 31 and the second test module 32 can be manually triggered or automatically triggered; the specific method is not limited here. The important point is that they cooperate with the control module 500 to achieve loop switching.

[0075] Understandably, the second end of the first test circuit 100 can branch into multiple test branches to connect to each of the devices under test (DUTs) 20, thus forming a multi-parallel measurement architecture. Under this architecture, the first test module 31 tests the parallel equivalent insulation resistance of all DUT paths. Based on the characteristics of parallel circuits, if the insulation between any adjacent DUTs 20 fails (i.e., a short circuit or low impedance occurs), the total insulation resistance of the entire circuit will decrease. Therefore, by simply determining whether the measured resistance value is lower than a preset safety threshold, i.e., whether an abnormally low resistance value has appeared, it is possible to quickly determine if the current insulation status is incorrect, thereby prompting the operator to troubleshoot the problem.

[0076] Furthermore, the architecture of this test circuit 10 reduces the number of fuses used. In existing test schemes, a four-wire sampling structure is typically used to achieve micro-ohm contact resistance testing. This means that each probe contact point requires two independent cables for driving and sensing, and each cable needs an independent fuse to prevent reverse short circuits caused by battery energy, resulting in twice the number of fuses as the number of sampling points. This application, however, uses a unique line multiplexing design to merge the low-voltage test signal injection path with the high-voltage test path, allowing each probe contact point to meet multiple testing requirements with only one physical cable. Therefore, compared to traditional solutions, this application reduces the number of fuses required.

[0077] It is important to note that the battery cell terminals should only be insulated from each other before they are soldered together by the busbar. If the busbar has already been soldered, the positive and negative terminals will be conductive, resulting in a short circuit and making it impossible to test insulation. Therefore, this test circuit 10 is used to apply high voltage to each component under test 20 before the module is soldered, testing whether an internal short circuit has occurred between them due to damage to the encapsulation insulation layer, thereby intercepting risky products with insulation failure in an early process.

[0078] In one feasible embodiment, the overall workflow of the test circuit 10 is as follows: First, it enters the low-voltage contact test stage. Responding to the low-voltage test command, the control module 500 prioritizes driving the isolation module 300 to perform a connection action, causing the probe module and contact module to physically contact each other, thereby connecting the second line 220; simultaneously, the control switching module 400 switches to the second mode. At this time, the low-voltage test signal output by the second test module 32 is injected into the first test circuit 100 via the first line 210, flows through the polarity terminals of each device under test 20, and then returns to the second test module 32 through the conducting isolation module 300 and the second line 220. The control module 500 determines whether the contact between the first test circuit 100 and each device under test 20 is good based on the feedback resistance value. If the resistance value is within a preset range, it is determined that the connection is in place. Subsequently, based on the confirmation of reliable physical connection, it enters the high-voltage insulation test stage. In response to a high-voltage test command, the control module 500 drives the isolation module 300 to perform a separation action, causing the probe module and contact module to separate, physically cutting off the second line 220 to form an air isolation gap, thereby protecting the second test module 32. Simultaneously, the control switching module 400 switches to the first mode. At this time, the first line 210 is disconnected from the device under test (DUT) 20, and the first test module 31 is directly connected to each DUT 20 through the first test circuit 100. Immediately afterwards, the control module 500 controls the first test module 31 to output a high-voltage signal to test the insulation resistance between each adjacent DUT 20, thereby completing the insulation performance evaluation of the battery module while ensuring safety.

[0079] Optionally, such as Figure 1 As shown, the switching module 400 may include a seventh switch K7 and an eighth switch K8. The eighth switch K8 is connected in series in the first test circuit 100. One end of the seventh switch K7 is connected to the first line 210, and the other end of the seventh switch K7 is connected to the end of the eighth switch K8 near the device under test 20. In the first mode, the eighth switch K8 is closed and the seventh switch K7 is open; in the second mode, the eighth switch K8 is open and the seventh switch K7 is closed.

[0080] In summary, the test circuit 10 of this embodiment, through the topology design of the switching module 400, the first test circuit 100, and the second test circuit 200, achieves path multiplexing of the low-voltage test signal to the high-voltage main transmission channel, avoiding the resource waste caused by independent high- and low-voltage wiring. Simultaneously, the introduction of a mechanically based isolation module 300 utilizes the physical separation of the probe and contact to construct an air insulation barrier, directly replacing the high-voltage relays that must be connected in series on each acquisition channel in the prior art to protect low-voltage instruments. Therefore, this test circuit 10 reduces the number of hardware components and optimizes the overall wiring space, thereby reducing structural redundancy.

[0081] In one embodiment, such as Figure 2 As shown, the plurality of test devices 20 include a plurality of first test devices 21 and a plurality of second test devices 22 arranged in an alternating manner; the first test circuit 100 has a third line 110 and a fourth line 120, the first end of the third line 110 is used to connect to the positive test terminal of the first test module 31, and the second end of the third line 110 is used to connect to the plurality of first test devices 21; the first end of the fourth line 120 is used to connect to the negative test terminal of the first test module 31, and the second end of the fourth line 120 is used to connect to the plurality of second test devices 22; the second end of the first line 210 is used to connect to each of the first test devices 21 through the third line 110, and to connect to each of the second test devices 22 through the fourth line 120.

[0082] In the first mode, the positive test terminal of the first test module 31 is connected to the first polarity terminal of a plurality of first test devices 21 through the third line 110, and the negative test terminal of the first test module 31 is connected to the second polarity terminal of a plurality of second test devices 22 through the fourth line 120. The first line 210 is disconnected from each of the first test devices 21 and each of the second test devices 22. In the second mode, the first test module 31 is disconnected from each of the first test devices 21 and each of the second test devices 22. The first line 210 is connected to each of the first test devices 21 through the third line 110 or to each of the second test devices 22 through the fourth line 120.

[0083] In this arrangement, multiple test pieces 20 are physically arrayed, comprising multiple columns extending longitudinally and / or multiple rows extending laterally. To achieve comprehensive testing of the insulation performance of adjacent test pieces 20, multiple first test pieces 21 and multiple second test pieces 22 are arranged in an alternating configuration within the array. For example, the alternating configuration can be an alternating arrangement longitudinally, where the test pieces 20 are arranged sequentially in the longitudinal direction in the order of "first test piece 21 - second test piece 22 - first test piece 21," ensuring that a potential difference is formed between each pair of longitudinally adjacent test pieces 20 through the first test circuit 100, thereby enabling insulation testing. Alternatively, the alternating configuration can also be an alternating arrangement laterally.

[0084] Based on this, the third line 110 is connected in parallel to all the first devices under test (DUTs) 21 as the first bus trunk, and the fourth line 120 is connected in parallel to all the second DUTs 22 as the second bus trunk. The first line 210 serves as the low-voltage signal injection channel, and its output is configured to selectively connect to the third line 110 and the fourth line 120 via the switching module 400. Thus, during low-voltage testing, the first line 210 can use either the third line 110 or the fourth line 120 as a transmission medium to time-division multiplex the corresponding DUT 20 to achieve signal injection.

[0085] Understandably, the first test module 31 can simultaneously connect the third line 110 and the fourth line 120, establishing a high-voltage potential difference between the interleaved first test device 21 and second test device 22 to test the insulation resistance between all adjacent first test devices 21 and second test devices 22 at once. The second test module 32 can utilize the first line 210 to connect two lines in the first test circuit 100 respectively, that is, it can connect the third line 110 or the fourth line 120 respectively, to test the probe contact resistance or circuit continuity of the first test device 21 and the second test device 22 respectively. This ensures that the physical connection between the first test circuit 100 and each test device 20 is reliable before performing high-voltage insulation testing, thereby avoiding the risk of misjudgment or arcing damage caused by loose probe connections.

[0086] In one feasible embodiment, the control logic of the test circuit 10 is configured to perform the following test steps: First, a low-voltage contact test phase is performed, controlling the isolation module 300 to enter the conduction state and controlling the switching module 400 to operate in the second mode. The first line 210 performs time-division scanning logic. First, the first line 210 is connected to the third line 110. At this time, the second test module 32 is used to test whether the test probe connection of all first test devices 21 is good. Then, the first line 210 is disconnected from the third line 110, and the fourth line 120 is connected. At this time, the second test module 32 is used to test the loop resistance of all second test devices 22 to confirm whether the test probe connection on the second test device 22 side is good. When the resistance values ​​tested in the above two steps are both within the preset qualified range, the current physical connection is determined to be reliable, and the high-voltage insulation test phase is performed; otherwise, an error is reported. During the high-voltage insulation test, the isolation module 300 enters isolation mode, and the switching module 400 switches to the first mode. The first line 210 is disconnected from each device under test (DUT) 20. Simultaneously, the positive test terminal of the first test module 31 is connected to all first DUTs 21 via the third line 110, and the negative test terminal is connected to all second DUTs 22 via the fourth line 120. Immediately afterwards, the first test module 31 outputs a high-voltage signal. Since the first DUTs 21 and second DUTs 22 are physically arranged in an alternating manner, this operation effectively establishes a high-voltage potential difference between each first DUT 21 and its adjacent second DUT 22. Therefore, the system only needs to read the total insulation resistance value fed back by the first test module 31 to determine whether there is insulation failure or short circuit between adjacent cells in the entire array, thus achieving efficient and comprehensive insulation performance evaluation.

[0087] In summary, by utilizing a topology combining interleaved grouping and line multiplexing, the insulation performance between each device under test (DUT) 20 is tested through a single high-voltage loading, improving testing efficiency. Furthermore, by controlling the switching module 400, low-voltage test signals can be transmitted via the high-voltage transmission trunk line, eliminating the need for a separate, complex low-voltage acquisition harness for the large battery array. This simplifies wiring, reduces the number of relays used, and ultimately reduces structural redundancy in the test circuit 10.

[0088] In one embodiment, such as Figure 3 As shown, the second end of the third line 110 is used to connect to the first polarity end of a plurality of first test devices 21, and the second end of the fourth line 120 is used to connect to the second polarity end of a plurality of second test devices 22. One of the first polarity end and the second polarity end is the positive terminal and the other is the negative terminal.

[0089] In this embodiment, as Figure 3As shown, the first polarity terminal is the positive terminal, and the second polarity terminal is the negative terminal. By connecting the first polarity terminal of the first device under test 21 to the third line 110, and connecting the second polarity terminal of the second device under test 22 to the fourth line 120, this embodiment establishes a clear high-voltage potential difference between two physically adjacent devices under test 20.

[0090] Understandably, the physical basis of insulation testing lies in applying a sufficient voltage difference across the insulating medium being tested. If adjacent test pieces 20 are all connected to the same polarity, they are at the same potential. In this case, even if there is damage or physical contact in the insulation layer between adjacent test pieces 20, no leakage current will be generated due to the lack of voltage drive, thus preventing the test circuit 10 from effectively testing. However, in this embodiment, by connecting the first test piece 21 to the positive terminal and the second test piece 22 to the negative terminal, a full high-voltage electric field is constructed between each test piece 20 and the physical gap between adjacent test pieces 20. Thus, given the potential difference, even minute insulation defects can be excited into a testable leakage current, ensuring the effectiveness of the insulation test.

[0091] Optionally, at least one third device under test (DUT) (not shown in the figure) may also be physically present between the first DUT 21 and the second DUT 22. In this configuration, the third DUT is electrically suspended, i.e., not directly connected to the first test circuit 100. When the first test module 31 applies a voltage between the first DUT 21 and the second DUT 22, the third DUT acts as an intermediate potential conductor, so that the test circuit covers the first insulation path between the first DUT 21 and the third DUT, as well as the second insulation path between the third DUT and the second DUT 22. It is understood that the first test module 31 tests the series equivalent insulation resistance of the aforementioned first and second insulation paths. Thus, the overall insulation performance between the third DUT and the live components on both sides can be verified incidentally by utilizing the penetrability of the high-voltage electric field, further simplifying the wiring harness arrangement.

[0092] It is understandable that multiple test devices 20 are arranged in series, that is, along the current transmission direction, the first polarity terminal (e.g., positive terminal) of the previous test device 20 is electrically connected to the second polarity terminal (e.g., negative terminal) of the adjacent test device 20, and the multiple test devices 20 are connected end to end in sequence.

[0093] In one embodiment, such as Figure 3 As shown, the second end of the second line 220 is used to connect the first polarity end of each first test piece 21 and the second polarity end of each second test piece 22, respectively.

[0094] Understandably, the third line 110 and the second line 220 are physically connected to the same polarity terminal of the device under test (DUT) 20, and the fourth line 120 and the second line 220 are also physically connected to the same polarity terminal of the DUT 20, achieving the effect of single-pole testing. In effect, a closed-loop test circuit is constructed at the contact point between the probe and the pole. This enables in-situ contact self-testing of the test probe, allowing the low-voltage test signal to originate from either the third line 110 or the fourth line 120, pass through the pole surface, and directly return via the second line 220. This means that the measured resistance value directly reflects the contact thermal resistance between the high-voltage probe and the pole. If this resistance value is within acceptable limits, it proves that the first test circuit 100 has been reliably connected to the corresponding pole.

[0095] In some exemplary technologies, a bipolar voltage test method is used to confirm the probe contact status, that is, by measuring the open-circuit voltage between the positive and negative terminals of the device under test to infer whether the probe is making good contact. However, this method requires extremely high precision of the measuring equipment, and in order to meet the production line cycle time, multiple 6.5-digit high-precision multimeters need to be configured for parallel data acquisition. In contrast, this embodiment uses a unipolar loop resistance test method, which, by testing the closed-loop resistance formed by the high-voltage and low-voltage lines on the same pole, can more directly and stably reflect the contact status, no longer relying on the voltage state of the battery itself. In this way, the test circuit 10 only needs one general-purpose resistance testing device (i.e., the second test module 32) to cooperate with the switching module 400 to complete the contact testing task of all channels, thereby improving the production line testing efficiency, reducing the equipment requirements, and lowering costs. In addition, using a unipolar arrangement of dual probes to test the resistance value effectively avoids the risk of short circuits. Traditional voltage testing methods require a pair of test probes to simultaneously contact the positive and negative terminals of the battery to form a measurement circuit. Under abnormal conditions such as mechanical vibration or probe slippage, the positive and negative terminals can easily become unintentionally connected through the test circuit, causing a short circuit and damaging the battery or the test probes. In contrast, the contact test in this embodiment is performed on only a single terminal, and the test circuit remains at the same potential throughout, eliminating any voltage difference. Since no cross-polarity connection is involved, a short circuit cannot be physically formed. Thus, the risk of short circuits is eliminated at the source, providing a safety guarantee.

[0096] In one embodiment, in the first mode, the first test terminal of the first test module 31 is connected to the first device under test 21 via the third line 110, and the second test terminal of the first test module 31 is connected to the second device under test 22 via the fourth line 120. The first line 210 is disconnected from each device under test 20. In the second mode, there are a first execution segment and a second execution segment. In the first execution segment, the first test module 31 is disconnected from each device under test 20, and the first line 210 is connected to the first polarity terminal of each first device under test 21 via the third line 110. In the second execution segment, the first test module 31 is disconnected from each device under test 20, and the first line 210 is connected to the second polarity terminal of each second device under test 22 via the fourth line 120.

[0097] The execution segments work in the first and second execution segments respectively. It can be either the first execution segment first and then the second execution segment, or the second execution segment first and then the first execution segment.

[0098] Optionally, the test circuit 10 further includes a control module 500, which is configured to: in response to a low-voltage test command, control the isolation module 300 to be in a conducting state, and control the switching module 400 to operate in a first execution segment and a second execution segment respectively, so as to determine the connection conduction state between each first test piece 21 and the third line 110, and the connection conduction state between each second test piece 22 and the fourth line 120 respectively; in response to a high-voltage test command, control the isolation module 300 to be in an isolated state, and control the switching module 400 to operate in a first mode, so as to determine the insulation resistance between each pair of adjacent test pieces 20 by the first test module 31.

[0099] In this embodiment, when the switching module 400 is in the first mode, the positive and negative test terminals of the first test module 31 are connected to the positive terminal of the first device under test 21 and the negative terminal of the second device under test 22 through the third line 110 and the fourth line 120, respectively, thereby constructing a high-voltage electric field across adjacent devices under test 20, that is, a high-voltage electric field between each first device under test 21 and each second device under test 22; at the same time, the first line 210 is disconnected from each device under test 20 to protect the second test module 32. Correspondingly, the second mode is subdivided into a first execution segment and a second execution segment. In the first execution segment, the switching module 400 connects the first line 210 only to the third line 110 to test the continuity between the third line 110 and each group of first devices under test 21; while in the second execution segment, the switching module 400 switches to connect the first line 210 only to the fourth line 120 to test the continuity between the fourth line 120 and each group of second devices under test 22. Based on the aforementioned hardware logic, in response to a low-voltage test command, the control module 500 prioritizes driving the isolation module 300 into a physical conduction state. Subsequently, it controls the switching module 400 to execute the first and second execution stages sequentially. This allows for the determination of the connection conduction status between each first device under test (DUT) 21 and the third line 110, and between each second DUT 22 and the fourth line 120. Once the test results of both execution stages are confirmed to be correct, the physical connection is deemed reliable. Subsequently, in response to a high-voltage test command, the control module 500 controls the isolation module 300 to enter an isolation state, using a physical gap to disconnect the low-voltage circuit; immediately afterward, it controls the switching module 400 to enter the first mode. At this time, the first test module 31 outputs high voltage, enabling the determination of the insulation resistance between each pair of adjacent DUTs 20 (i.e., the first DUT 21 and the second DUT 22) in a single operation.

[0100] Thus, this embodiment achieves low-voltage testing for single-pole mode and multiplexing the transmission path of the first test circuit 100 by subdividing the low-voltage test mode into 20 independent execution segments for different test devices.

[0101] In one embodiment, such as Figure 4 As shown, the first test circuit 100 also includes a fifth line 130. One end of the fifth line 130 is connected to the second test terminal of the first test module 31, and the other end of the fifth line 130 is used to connect to the packaging shell 41 of multiple devices under test 20.

[0102] The fifth line 130 can be an extension of the third line 110 or the fourth line 120, or a dedicated ground line independently connected to the second test terminal of the first test module 31. The fifth line 130 is equipped with contact components for establishing an electrical connection with the housing, such as a magnetic probe, grounding clamp, or threaded terminal, thereby bringing the battery module's encapsulation housing 41 to a reference potential terminal, such as the negative terminal or ground terminal.

[0103] The encapsulation housing 41 refers to the external conductive structural component used to house, fix, and protect multiple test pieces 20, such as an aluminum alloy casing, a stainless steel base, a metal side plate, or a top cover. In a battery module, the encapsulation housing 41 typically serves as the main mechanical support for the module and the grounding reference for electrical safety regulations. Under normal circumstances, the encapsulation housing 41 must maintain strict electrical isolation from the individual cell terminals inside; if insulation failure occurs between the two, it will not only lead to power leakage but may also cause electric shock accidents when a person comes into contact with the housing.

[0104] This embodiment utilizes the fifth line 130 to test the overall insulation performance of the battery module to ground. The specific testing method is as follows: the control module 500 controls the switching module 400 to operate in full parallel mode, internally shorting and combining the third line 110 and the fourth line 120, and connecting them uniformly to the high-voltage output terminal (e.g., positive terminal) of the first test module 31, ensuring that all first test components 21 and second test components 22 are at the same potential. Simultaneously, the fifth line 130 connects the encapsulation shell 41 to the return terminal (e.g., negative terminal) of the first test module 31. Subsequently, the first test module 31 outputs a high voltage to test the insulation resistance between all charged cells as a whole and the encapsulation shell 41.

[0105] In one embodiment, in the first mode, the switching module 400 connects the first test terminal of the first test module 31 to the first device under test 21 via the third line 110, and the second test terminal of the first test module 31 to the second device under test 22 via the fourth line 120. The first line 210 is disconnected from each device under test 20. In the second mode, which includes a first execution segment and a second execution segment, the switching module 400 disconnects the first test module 31 from each device under test 20 in the first execution segment, and the first line 210 connects the first polarity of each first device under test 21 via the third line 110. In the second execution phase, the switching module 400 disconnects the first test module 31 from each device under test 20, and the first line 210 connects to the second polarity terminal of each second device under test 22 through the fourth line 120. In the third mode, the first end of the fourth line 120 is connected to the third line 110, the first test terminal of the first test module 31 connects to each device under test 20 through the third line 110 and the fourth line 120, the fifth line 130 connects to the second test terminal of the first test module 31, and the first line 210 is disconnected from each device under test 20.

[0106] Optionally, the test circuit 10 further includes a control module 500, which is configured to: in response to a low-voltage test command, control the isolation module 300 to be in a conducting state, and control the switching module 400 to operate in a first execution segment and a second execution segment respectively, so as to determine the connection conduction state between each first test device 21 and the third line 110, and the connection conduction state between each second test device 22 and the fourth line 120 respectively; in response to a first high-voltage test command, control the isolation module 300 to be in an isolated state, and control the switching module 400 to operate in a first mode, so as to determine the insulation resistance between each two adjacent test devices 20 through the first test module 31; in response to a second high-voltage test command, control the isolation module 300 to be in an isolated state, and control the switching module 400 to operate in a third mode, so as to determine the insulation resistance between each test device 20 and the package housing 41 through the first test module 31.

[0107] The execution segments work in the first and second execution segments respectively. It can be either the first execution segment first and then the second execution segment, or the second execution segment first and then the first execution segment.

[0108] In one feasible implementation, in response to a low-voltage test command, the control module 500 controls the isolation module 300 to perform a mechanical closing action, causing the probe module and contact module of the isolation module 300 to physically contact each other, thereby connecting the second line 220 to form a low-voltage signal return path. Subsequently, the control module 500 drives the switching module 400 to execute time-division scanning logic: firstly, entering the first execution stage, the first line 210 is connected to each of the first devices under test 21 via the third line 110. At this time, the low-voltage test signal is emitted by the second test module 32, injected into the third line 110 via the first line 210, flows through the terminal contact points of all the first devices under test 21, and finally returns through the second line 220; then, entering the second execution stage, the first line 210 is connected to each of the second devices under test 22 via the fourth line 120, and the loop resistance of all the second devices under test 22 is tested along the same path. In this way, the low-voltage signal is used to confirm whether the physical connection between the first test loop 100 and each device under test 20 is reliable, and the resistance value is used to determine whether there is a loose connection.

[0109] In one feasible implementation, in response to a first high-voltage test command, the insulation resistance test between the various test components 20 begins. The control module 500 first controls the isolation module 300 to perform a mechanical separation action, disconnecting the second line 220 to form an air insulation gap, cutting off the path of the first test module 31, and protecting the second test module 32. Subsequently, the control module 500 drives the switching module 400 to switch to the first mode. The first line 210 is disconnected, and the positive terminal of the first test module 31 is applied to each of the first test components 21 via the third line 110, while the negative terminal is applied to each of the second test components 22 via the fourth line 120. At this time, the test signal path is: positive terminal of the first test module 31 → third line 110 → first test component 21 → second test component 22 → fourth line 120 → negative terminal of the first test module 31. Since the two sets of test pieces 20 are physically adjacent to each other, a high-voltage electric field stress is established at both ends of the insulation gap of each pair of adjacent test pieces 20. This not only allows for testing of insulation resistance, but also for verifying the dielectric strength between adjacent cells by monitoring leakage current. This allows for a one-time screening of whether there is a risk of electrical breakdown or micro-short circuit in the array due to insufficient withstand voltage.

[0110] In one feasible implementation, in response to a second high-voltage test command, an insulation withstand voltage test is initiated between each device under test (DUT) 20 and the package housing 41. The control module 500 controls the isolation module 300 to be in an isolated state to protect the second test module 32, and drives the switching module 400 to switch to a third mode. At this time, the third line 110 and the fourth line 120 are short-circuited and connected to the positive terminal of the first test module 31; simultaneously, the fifth line 130 connecting the package housing 41 is connected to the negative terminal of the first test module 31. At this point, all first DUTs 21 and second DUTs 22 are forced to the same high potential, forming an equipotential conductor. The test signal path is: positive terminal of the first test module 31 → third line 110 and fourth line 120 → all DUTs 20 → package housing 41 → fifth line 130 → negative terminal of the high-voltage source. This verifies the insulation withstand voltage performance between each DUT 20 and the package housing, and checks for potential safety hazards such as ground leakage or damage to the package insulation layer.

[0111] Through the above embodiments, this embodiment achieves contact reliability verification, insulation withstand voltage assessment between devices under test (DUTs) 20, and insulation withstand voltage assessment of DUTs 20 to ground by coordinating the three operating modes of the switching module 400 with the timing of the control module 500. In this way, the structural redundancy of the test circuit 10 is simplified through line reuse, achieving efficient, low-cost, and highly reliable automated testing.

[0112] In one embodiment, such as Figure 4 As shown, the switching module 400 includes a first switch K1, a second switch K2, a third switch K3, a fourth switch K4, a fifth switch K5, and a sixth switch K6. The first switch K1 is connected in series in the third line 110. The first end of the first switch K1 is used to connect to the positive test terminal of the first test module 31, and the second end of the first switch K1 is used to connect to the first polarity terminal of multiple first test devices 21. The second switch K2 is connected in series in the fourth line 120. The first end of the second switch K2 is used to connect to the negative test terminal of the first test module 31, and the second end of the second switch K2 is used to connect to the second polarity terminal of multiple second test devices 22. The third switch K3 is connected between the second end of the first switch K1 and the second end of the second switch K2. The fourth switch K4 is connected between the first line 210 and the first end of the first switch K1. The fifth switch K5 is connected between the first line 210 and the first end of the second switch K2. The sixth switch K6 is connected in series in the fifth line 130.

[0113] It is understandable that the first switch K1, the second switch K2, the third switch K3, the fourth switch K4, the fifth switch K5, and the sixth switch K6 can all be relay switches, or other types of switches, which are not limited here. Each switch can be uniformly controlled by the control module 500. However, considering that the test circuit needs to withstand high-voltage insulation testing, the first to sixth switches K6 can be high-voltage relays or high-voltage reed switches. The control module 500 controls the opening and closing of each switch by outputting IO control signals or drive current.

[0114] In one feasible implementation, the control module 500 responds to a low-voltage test command by executing time-division control logic to confirm probe connection. In the first execution phase, the control module 500 controls the fourth switch K4 and the first switch K1 to close, and places the second switch K2, the third switch K3, the fifth switch K5, and the sixth switch K6 all in the open state. At this time, the low-voltage signal originates from the first line 210, enters the first terminal of the first switch K1 via the fourth switch K4, passes through the first switch K1, and reaches the third line 110 and the first device under test (DUT) 21, testing the contact with each of the first DUTs 21. Subsequently, in the second execution phase, the control module 500 controls the fifth switch K5 and the second switch K2 to close, and places the first switch K1, the third switch K3, the fourth switch K4, and the sixth switch K6 all in the open state. At this time, the low-voltage signal is directly injected into the first terminal of the second switch K2 via the fifth switch K5, thereby testing the probe connection status of each of the second DUTs 22.

[0115] In one feasible embodiment, the control module 500, in response to a first high-voltage test command, controls the first switch K1 and the second switch K2 to close, and puts the third switch K3, the fourth switch K4, the fifth switch K5, and the sixth switch K6 all in the open state. In this state, the positive test terminal of the first test module 31 transmits power losslessly to each of the first test devices 21 through the closed first switch K1, and the negative test terminal transmits power to each of the second test devices 22 through the closed second switch K2. This topology allows the high-voltage power supply to be directly applied between the staggered adjacent first test devices 21 and second test devices 22, thereby determining their internal insulation resistance.

[0116] In one feasible implementation, the control module 500 responds to a second high-voltage test command by closing the first switch K1, the third switch K3, and the sixth switch K6, while simultaneously opening the second switch K2, the fourth switch K4, and the fifth switch K5. The logic is as follows: the first switch K1 introduces the high-voltage positive electrode into the third line 110; the closed third switch K3 short-circuits the third line 110 and the fourth line 120 on the side of the device under test 20, thereby bringing the second device under test 22 to the high-voltage positive electrode as well; simultaneously, the closed sixth switch K6 connects the fifth line 130 to the negative electrode of the tester. At this time, all devices under test 20 are at a high potential, while the encapsulation shell 41 is at a low potential, thus achieving the test of the overall insulation withstand voltage performance of the battery module.

[0117] It should be noted that the layout of the first switch K1 to the sixth switch K6 in other embodiments may differ from that in this application, and may have different implementation methods. However, their purpose is to cooperate with each other to achieve various tests. Therefore, it is sufficient to switch each test by means of the first switch K1 to the sixth switch K6.

[0118] In summary, this embodiment achieves the switching of three different circuit configurations on the same physical wiring harness through a specific connection combination of six switches. Compared to the existing test circuit 10, which requires more than 300 relays, this solution uses only 6 relays, simplifying the hardware wiring and hardware requirements of the test circuit 10 and reducing hardware redundancy.

[0119] In one embodiment, such as Figure 5 As shown, the isolation module 300 includes a drive unit 310, a first connection module 320, and a second connection module 330. The first connection module 320 and the second connection module 330 are connected in series on the second line 220. The drive unit 310 is driven to at least one of the first connection module 320 and the second connection module 330. The drive unit 310 is configured to: drive the first connection module 320 and the second connection module 330 to abut against each other to conduct the second line 220; and drive the first connection module 320 and the second connection module 330 to separate from each other to disconnect the second line 220.

[0120] The drive unit 310 can be a linear actuator such as a cylinder, linear motor, or electromagnetic push rod; the first connecting module 320 and the second connecting module 330 can be mutually cooperating conductive contacts, probes, and contact electrodes. For example, the first connecting module 320 is fixed to the stationary end, and the second connecting module 330 is mounted on the output shaft of the drive unit 310. When the drive unit 310 operates, it can drive the second connecting module 330 to move, thereby achieving mechanical contact with the first connecting module 320 to enter a conductive state, or mechanical separation to enter an isolated state. Alternatively, the first connecting module 320 can be mounted on the drive unit 310, and the second connecting module can be fixed; or both the first connecting module 320 and the second connecting module 330 can be mounted on the drive unit 310. The specific configuration is not limited here, as long as mutual displacement between the first and second connecting modules can be achieved.

[0121] Understandably, this design utilizes the high impedance characteristics of an air-insulated gap. When the drive unit 310 drives the two connection modules to separate, the second line 220 is physically severed, creating a sufficiently long air gap at the break point. Because air has an extremely high breakdown voltage under standard atmospheric pressure and does not exhibit the leakage current phenomenon commonly seen in semiconductor devices, this physical isolation method ensures that during high-voltage insulation testing, high-voltage signals absolutely cannot be introduced into the second test module 32 through the second line 220.

[0122] More importantly, this isolation module 300 replaces all existing relay isolation protection schemes. In traditional designs, to prevent high-voltage test signals from damaging the low-voltage acquisition instrument (second test module 32), a withstand voltage relay is usually connected in series on the low-voltage return line, increasing hardware costs and the complexity of the control system. In contrast, this embodiment can construct an electrical performance isolation barrier without relying on any electronic switching devices. This reduces the structural redundancy of the test circuit 10.

[0123] In one embodiment, the first connection module 320 has a plurality of first electrical connectors, and the second connection module 330 has a plurality of second electrical connectors; the first ends of the plurality of first electrical connectors are used to connect one-to-one with a plurality of devices under test 20, the second ends of the plurality of first electrical connectors are used to connect one-to-one with the first ends of the plurality of second electrical connectors, and the second ends of the plurality of second electrical connectors are used to connect to the second test end of the second test module 32; the driving unit 310 can drive the plurality of first electrical connectors and the plurality of second electrical connectors to connect one-to-one and enter a conducting state to conduct the second line 220; and can drive the plurality of first electrical connectors and the plurality of second electrical connectors to move away from each other and enter an isolation state to disconnect the second line 220.

[0124] In this embodiment, the first electrical connector essentially constitutes a front-end probe assembly connecting the device under test (DUT) 20, and its number corresponds one-to-one with the number of DUTs 20; while the second electrical connector constitutes a rear-end adapter assembly connecting the second test module 32. These two connectors are physically designed as male and female terminals or contact points that can mate with each other.

[0125] Understandably, when low-voltage testing is required, the drive unit 310 drives the second connection module 330 to move towards the first connection module 320, causing multiple pairs of first and second electrical connectors to make physical contact simultaneously. At this time, all low-voltage sampling signals from the device under test (DUT) 20 are seamlessly transmitted to their respective second electrical connectors through their first electrical connectors and ultimately converge into the second test module 32, achieving parallel conduction of multi-channel signals. Conversely, when switching to high-voltage testing, the drive unit 310 drives the second connection module 330 to move in the opposite direction, causing all first and second electrical connectors to separate. At this time, a physical breakpoint is formed on each low-voltage sampling channel, thereby isolating all front-end probes connected to the DUT 20 from the rear-end second test module 32.

[0126] This application also provides a testing apparatus, which includes the testing circuit 10 as described above.

[0127] It should be noted that the specific embodiment of the test circuit 10 is described above. Since this test device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0128] In one embodiment, the testing device further includes a probe module, which has a first probe group and a second probe group, each having multiple test probes; the first ends of the multiple test probes in the first probe group are used to connect to the first test circuit 100, and the second ends of the multiple test probes in the first probe group are used to connect one-to-one with multiple devices under test 20; the first ends of the multiple test probes in the second probe group are used to connect to the isolation module 300, and the second ends of the multiple test probes in the second probe group are used to connect one-to-one with multiple devices under test 20.

[0129] Optionally, the number of test probes in the first and second probe groups is not limited and depends on the actual testing requirements. When a full-coverage test of the insulation performance between each pair of adjacent test pieces 20 is required, the number of test probes in the first probe group and the number of test probes in the second probe group should at least maintain a one-to-one correspondence with the number of test pieces 20. This ensures that each polarity terminal of each test piece 20 is assigned at least one test probe from the first probe group and one test probe from the second probe group, thus providing a complete hardware contact interface for implementing dual-loop parallel testing for each single pole, guaranteeing test integrity. However, in scenarios where it is not necessary to test every adjacent unit, but only to test the insulation condition between every two groups of test pieces 20 (a group of test pieces 20 may include multiple independent test pieces 20), the number of test probes in each probe group can be reduced accordingly.

[0130] The first probe group is the high-voltage loading probe used in the first test circuit 100, used to carry high voltage or high current; the second probe group is the low-voltage sampling probe used in the second test circuit 200, used to transmit test signals. Therefore, the low-voltage test described above actually tests the contact between the first probe group and each device under test (DUT) 20 by testing the loop resistance between the second probe group and the first probe group. Only when the first probe group has stably contacted the electrode can the subsequent first test module 31 apply the high-voltage excitation signal to each DUT 20 through the first probe group, thereby avoiding arcing accidents caused by the high-voltage probes being suspended.

[0131] Understandably, since the first device under test (DUT) 21 and the second DUT 22 are alternately arranged, and the first test circuit 100 includes a third line 110 and a fourth line 120, the first probe group can logically be divided into two probe subgroups. One end of the first probe subgroup is used to connect all the first DUTs 21, and the other end is connected to the second end of the third line 110; while one end of the second probe subgroup is used to connect all the second DUTs 22, and the other end is connected to the second end of the fourth line 120.

[0132] In one embodiment, the testing device further includes a parallel module 60, which is connected between the first test circuit 100 and the first probe group; the parallel module 60 is used to connect the first ends of each test probe in the first probe group to the first test circuit 100 in parallel.

[0133] The parallel module 60 can be a PCB adapter board or copper busbar integrated on the back of the probe module. Its internal circuit layout can include two isolated conductive networks, namely the bus area corresponding to the third line 110 and the bus area corresponding to the fourth line 120. In this way, the parallel module 60 can connect the third line 110 and the fourth line 120 from the first test circuit 100 in a one-to-many manner at the probe end, thereby distributing the electrical signal in parallel to each specific test probe in the first probe group.

[0134] Understandably, by connecting the probe modules in parallel nearby, the testing device does not need to run hundreds of high-voltage cables from the control cabinet to connect each probe separately, but only needs to run the main line to connect to the parallel module 60.

[0135] Importantly, this application achieves a wire-harness-free design for the test circuit by physically integrating the isolation module 300 and the parallel module 60 onto a bracket. Compared to traditional solutions where each probe requires an independent lead to the control cabinet, this embodiment only utilizes the main cable for power supply, and high-voltage fan-out is achieved at the probe board end using PCB printed circuits or copper busbars. This reduces the amount of high-voltage silicone wire used, lowering the structural redundancy of the test circuit 10 and even the test device. Simultaneously, this design, which integrates low-voltage sampling and high-voltage loading circuits into the same compact structure, eliminates complex flying wire interference, greatly improving the system's anti-interference capability and operational reliability.

[0136] This application also provides a test fixture 50, which includes the test circuit 10 as described above, or the test device as described above.

[0137] It should be noted that the specific embodiments of the test circuit 10 and the test device are described above. Since this test fixture 50 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0138] In one embodiment, such as Figure 6 As shown, Figure 6 This is a simplified schematic diagram of the test fixture 50, which includes a support frame that serves as the skeleton of the entire fixture. The support frame houses the aforementioned probe module, parallel module 60, etc. Optionally, the support frame has at least two independent mounting positions along the vertical or horizontal direction: the first mounting position is used to mount the isolation module 300; the second mounting position is used to fix the parallel module 60.

[0139] Optionally, to improve assembly efficiency and ease of maintenance, a U-shaped groove quick-connect structure is used between the pressing cylinder of the isolation module 300 (i.e., one embodiment of the drive unit 310) and the overall mechanism of the isolation module 300. The piston rod or mounting bracket of the cylinder is connected to the actuator via a sliding U-shaped groove, allowing for quick positioning and locking of the cylinder without completely removing the bolts, thus shortening replacement time. In conjunction with this, a clamping fixing structure is used between the low-voltage inlet adapter plate and the mounting base plate. Using pressure plates, clips, or quick clamps, operators can quickly assemble and disassemble the adapter plate by hand or with only simple tools, improving equipment maintainability and reducing the time cost of production line downtime for equipment repairs.

[0140] Optionally, the isolation module 300 adopts an integrated design, integrating key components such as quick-connect connectors, test probes, and overcurrent protection fuses onto the same circuit board. This design not only reduces the physical size of the module but also effectively reduces the number of solder joints between discrete components, improving system integration. Optionally, the positive and negative circuit areas on the isolation module 300 employ physical board isolation or slotted isolation design to ensure that a minimum 5mm air insulation gap is always maintained between the two circuit boards.

[0141] Optionally, the isolation module 300 can be connected to the bracket using insulating fasteners such as nylon bolts, which cuts off the creepage path and improves the overall insulation withstand voltage performance and stability.

[0142] Optionally, considering the potential presence of metal dust or electrolyte volatiles in battery production workshops, the output terminals of the isolation module 300 can be equipped with a sealing structure, such as a gland, to achieve a waterproof and dustproof seal at the cable penetration point by tightening the nut and compressing the internal rubber ring. Simultaneously, the probe and contact pressing mechanism of the isolation module 300 adopts a fully enclosed cavity design, using sealing gaskets or a labyrinth seal structure to isolate the contacts from the external environment. This prevents conductive dust from entering the contact gap and causing micro-short circuits or insulation degradation, thus improving the reliability of the isolation module 300.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no technical conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A test circuit, characterized in that, Used for testing multiple devices under test (DUTs), wherein the multiple DUTs include multiple first DUTs and multiple second DUTs arranged in an alternating manner; The test circuit includes: The first test circuit has a third line and a fourth line. The first end of the third line is used to connect to the positive test terminal of the first test module, and the second end of the third line is used to connect to the first polarity terminal of a plurality of first test devices. The first end of the fourth line is used to connect to the negative test terminal of the first test module, and the second end of the fourth line is used to connect to the second polarity terminal of a plurality of second test devices. One of the first polarity terminal and the second polarity terminal is positive and the other is negative. The second test circuit has a first line and a second line. The first end of the first line is used to connect to the first test end of the second test module, and the second end of the first line is used to connect to each first device under test (DUT) through the third line and to connect to each second DUT through the fourth line. The first end of the second line is used to connect to the second test end of the second test module, and the second end of the second line is used to connect to each DUT. The first test module is a high-voltage test module, and the second test module is a low-voltage test module. The switching module can switch between a first mode and a second mode. In the first mode, the positive test terminal of the first test module is connected to the first polarity terminal of a plurality of first devices under test (DUTs) through the third line, and the negative test terminal of the first test module is connected to the second polarity terminal of a plurality of second DUTs through the fourth line. The first line is disconnected from each of the first DUTs and each of the second DUTs. In the second mode, the first test module is disconnected from each of the first DUTs and each of the second DUTs. The first line is connected to each of the first DUTs through the third line or to each of the second DUTs through the fourth line. An isolation module, connected in series in the second line, can switch between a conductive state and a mechanically isolated state.

2. The test circuit as described in claim 1, characterized in that, The second end of the second line is used to connect the first polarity terminal of each first device under test and the second polarity terminal of each second device under test, respectively.

3. The test circuit as described in claim 2, characterized in that, In the first mode, the first test terminal of the first test module is connected to the first device under test (DUT) through the third line, and the second test terminal of the first test module is connected to the second DUT through the fourth line. The first line is disconnected from each DUT. The second mode includes a first execution segment and a second execution segment. In the first execution segment, the switching module disconnects the first test module from each device under test (DUT), and the first line connects to the first polarity terminal of each first DUT through the third line. In the second execution segment, the switching module disconnects the first test module from each DUT, and the first line connects to the second polarity terminal of each second DUT through the fourth line.

4. The test circuit as described in claim 3, characterized in that, The test circuit also includes a control module, which is configured to: In response to a low-voltage test command, the isolation module is controlled to be in the conducting state, and the switching module is controlled to operate in the first execution segment and the second execution segment respectively; In response to a high-voltage test command, the isolation module is controlled to be in an isolated state, and the switching module is controlled to operate in the first mode.

5. The test circuit as described in claim 2, characterized in that, The first test circuit also includes a fifth line, one end of which is connected to the second test terminal of the first test module, and the other end of which is used to connect to the packaging shell of multiple devices under test.

6. The test circuit as described in claim 5, characterized in that, The switching module can switch between a first mode, a second mode, and a third mode; In the first mode, the first test terminal of the first test module is connected to the first device under test (DUT) through the third line, and the second test terminal of the first test module is connected to the second DUT through the fourth line. The first line is disconnected from each DUT. The second mode includes a first execution segment and a second execution segment. In the first execution segment, the switching module is disconnected from each device under test (DUT), and the first line is connected to the first polarity terminal of each first DUT through the third line. In the second execution segment, the switching module is disconnected from each DUT, and the first line is connected to the second polarity terminal of each second DUT through the fourth line. In the third mode, the switching module connects the first end of the fourth line to the third line, the first test end of the first test module connects to each device under test through the third and fourth lines, the fifth line connects to the second test end of the first test module, and the first line disconnects from each device under test.

7. The test circuit as described in claim 6, characterized in that, The test circuit also includes a control module, which is further configured to: In response to a low-voltage test command, the isolation module is controlled to be in the conducting state, and the switching module is controlled to operate in the first execution segment and the second execution segment respectively; In response to the first high-voltage test command, the isolation module is controlled to be in an isolated state, and the switching module is controlled to operate in the first mode; In response to the second high-voltage test command, the isolation module is controlled to be in an isolated state, and the switching module is controlled to operate in the third mode.

8. The test circuit as described in any one of claims 5 to 7, characterized in that, The switching module includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch; The first switch is connected in series in the third circuit. The first end of the first switch is used to connect to the positive test terminal of the first test module, and the second end of the first switch is used to connect to the first polarity terminal of a plurality of first test devices. The second switch is connected in series in the fourth circuit. The first end of the second switch is used to connect to the negative test terminal of the first test module, and the second end of the second switch is used to connect to the second polarity terminal of a plurality of second test devices. The third switch is connected between the second end of the first switch and the second end of the second switch; the fourth switch is connected between the first line and the first end of the first switch; the fifth switch is connected between the first line and the first end of the second switch; and the sixth switch is connected in series in the fifth line.

9. The test circuit as described in claim 1, characterized in that, The isolation module includes a driving unit, a first connection module, and a second connection module. The first connection module and the second connection module are connected in series on the second line. The driving unit is driven to at least one of the first connection module and the second connection module. The driving unit is configured to drive the first connection module and the second connection module to abut against each other to conduct the second line; And it can drive the first connection module and the second connection module to separate from each other to disconnect the second line.

10. The test circuit as described in claim 9, characterized in that, The first connection module has multiple first electrical connectors, and the second connection module has multiple second electrical connectors; The first ends of the plurality of first electrical connectors are used to connect one-to-one with the plurality of devices under test, the second ends of the plurality of first electrical connectors are used to connect one-to-one with the first ends of the plurality of second electrical connectors, and the second ends of the plurality of second electrical connectors are used to connect to the second test end of the second test module; The driving unit can drive multiple first electrical connectors and multiple second electrical connectors to connect one-to-one and enter a conducting state to conduct the second line. And capable of driving multiple first electrical connectors and multiple second electrical connectors to move away from each other, entering an isolation state to disconnect the second line.

11. A testing apparatus, characterized in that, The testing apparatus includes the testing circuit as described in any one of claims 1 to 10.

12. The testing apparatus as described in claim 11, characterized in that, The testing device further includes a probe module, which has a first probe group and a second probe group, each of which has multiple test probes. The first ends of the multiple test probes in the first probe group are all used to connect to the first test circuit, and the second ends of the multiple test probes in the first probe group are used to connect to multiple devices under test one-to-one. The first ends of the multiple test probes in the second probe group are all used to connect to the isolation module, and the second ends of the multiple test probes in the second probe group are used to connect one-to-one with multiple devices under test.

13. The testing apparatus as described in claim 12, characterized in that, The testing device further includes a parallel module, which is connected between the first test circuit and the first probe group; the parallel module is used to connect the first ends of each test probe in the first probe group to the first test circuit in parallel.

14. A testing fixture, characterized in that, The test fixture includes a test circuit as described in any one of claims 1 to 10, or a test device as described in any one of claims 12 to 13.

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