Self-discharge test fixture and system

Abstract

The present disclosure relates to the field of battery cell testing, and provides a self-discharge test fixture and system. The fixture includes a fixture body having a battery cell test site for receiving a battery cell under test; a limiting mechanism disposed on the fixture body for limiting the battery cell under test at the battery cell test site; at least one conductive mechanism disposed on the fixture body and having a first electrical connection end and a second electrical connection end in conductive connection; the first electrical connection end is in conductive connection with a self-discharge test device; and the conductive mechanism is configured to move to electrically contact the second electrical connection end with at least one electrode end of the battery cell under test in response to the battery cell under test being loaded at the battery cell test site, so as to conduct a discharge test signal path of the battery cell under test to the self-discharge test device. The embodiments of the present disclosure realize simultaneous linkage between loading and positioning of the battery cell under test and electrical connection of the electrode end, and the discharge test signal path is conducted after the battery cell under test is limited at the battery cell test site, which can improve the clamping efficiency of the battery cell during the self-discharge test.

Description

Technical Field

[0001] This disclosure relates to the field of battery cell testing, and in particular to self-discharge testing fixtures and systems. Background Technology

[0002] A battery cell is the electrochemical unit of a battery, a fundamental functional module for converting electrical energy into chemical energy, and an important component of a battery pack. During cell production, sorting, aging, and factory testing, self-discharge tests are typically performed to evaluate the cell's charge retention capability under static or other specified test conditions.

[0003] Existing self-discharge testing equipment typically includes a test fixture for carrying the battery cell under test, probes or conductive terminals connected to the battery cell's terminals, and testing instruments for acquiring voltage and current data. During testing, the battery cell under test is placed in the test fixture, and then the probe is moved to electrically connect the battery cell's terminals to the probe, thus forming a test signal path between the battery cell under test and the self-discharge testing device.

[0004] However, in existing test fixtures, the conductive terminals are usually fixed, requiring operators to perform additional crimping, clamping, or insertion operations after the battery cell under test is loaded to ensure that the probes or conductive terminals contact the electrode ends of the battery cell. The conductive terminals may obstruct the space for the battery cell to enter the test position during loading, requiring additional clearance operations and affecting the ease of handling the battery cell. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this disclosure is to provide a self-discharge test fixture and system to solve the problems in the related art.

[0006] The first aspect of this disclosure provides a self-discharge test fixture for use with a self-discharge test device to test a battery cell under test, comprising: a fixture body having a cell test position for accommodating the battery cell under test; a limiting mechanism disposed on the fixture body for limiting the battery cell under test to the cell test position; and at least one conductive mechanism disposed on the fixture body having a first electrical connection terminal and a second electrical connection terminal electrically connected; the first electrical connection terminal being electrically connected to the self-discharge test device; and the conductive mechanism being configured to move in response to the battery cell under test being loaded into the cell test position, such that the second electrical connection terminal electrically contacts at least one electrode of the battery cell under test, thereby conducting a discharge test signal path from the battery cell under test to the self-discharge test device.

[0007] In a first aspect embodiment, the conductive mechanism includes: a rotating shaft portion disposed on the fixture body; and a rotating member rotatably coupled to the rotating shaft portion, wherein a pressure-bearing portion and a second electrical connection terminal are respectively formed in two parts divided by the rotating shaft portion; wherein the pressure-bearing portion is disposed at the cell testing position and located on the movement path of the cell under test being loaded onto the cell testing position, so as to be pressed against the cell under test, causing the rotating member to rotate and bring the second electrical connection terminal closer to the electrode of the cell until contact.

[0008] In the first aspect of the embodiment, the conductive mechanism further includes: a reset elastic member, one end of which is connected to and fixed on the fixture body, and the other end of which is connected to and fixed on the conductive mechanism; the reset elastic member is used to apply a reset force to the conductive mechanism after the cell under test is displaced from the cell test displacement, so as to drive the conductive mechanism to rotate in the opposite direction around the rotating shaft, so as to cause the rotating member to rotate in a way that moves the second electrical connection terminal away from the electrode of the cell under test.

[0009] In an embodiment of the first aspect, the conductive mechanism and / or the rotating member are position-adjustable along the shaft portion to allow adjustment so that the electrode terminals of the battery cell under test are aligned in the rotational path of the second electrical connection terminal.

[0010] In an embodiment of the first aspect, at least one of the following is further included: (1) the conductive mechanism includes: a motor-driven transport mechanism configured to drive the conductive mechanism based on position adjustment information to cause the second electrical connection terminal to contact the electrode terminal in response to the cell under test being loaded onto the cell test position; (2) the limiting mechanism includes at least one adjustable limiting member for adjusting the position to change the size of the cell test position to fit the cell under test; (3) the limiting mechanism further includes a clamping component movable to cover or be removed from the cell test position for clamping the cell under test located on the cell test position.

[0011] The second aspect of this disclosure provides a self-discharge testing system for performing self-discharge testing on at least one battery cell under test (BUT) on a self-discharge testing fixture as described in the first aspect. The system includes: at least one fixture receiving cavity for accommodating at least one of the self-discharge testing fixtures; a temperature control component for acquiring sampling temperature values ​​of each of the BUTs, and for controlling the temperature of each BUT based on the deviation between the sampling temperature value of each BUT and a preset target test temperature; a self-discharge testing device electrically connected to a conductive mechanism on each of the self-discharge testing fixtures, the self-discharge testing device including a data acquisition unit, the data acquisition unit being configured to acquire self-discharge test data corresponding to the BUT in response to detecting that a second electrical connection terminal of any of the self-discharge testing fixtures is electrically connected to the electrode of the corresponding BUT and that the sampling temperature value of the BUT reaches the preset target test temperature; the self-discharge testing device further includes a data processing unit, the data processing unit being configured to process the self-discharge test data using preset self-discharge test evaluation rules to determine the self-discharge test result of the BUT.

[0012] In the second aspect of the embodiment, the self-discharge testing device provides an actual testing interface through deployed self-discharge testing software to receive test configuration parameters of each of the self-discharge testing fixtures, controls the acquisition unit and / or the temperature control component to perform tests based on the test configuration parameters, and displays the self-discharge test data acquired by the acquisition unit; wherein, the test configuration parameters include at least one of overcurrent threshold, overvoltage threshold, and undervoltage threshold, and the self-discharge test data includes at least one of self-discharge testing fixture identification, sampling time, open circuit voltage data, and self-discharge current data.

[0013] In the second aspect of the embodiment, the preset self-discharge test evaluation rule includes at least one of a self-discharge current evaluation rule, an open-circuit voltage decay rate evaluation rule, and a temperature validity evaluation rule; wherein, the current evaluation rule includes: determining the self-discharge test result of the cell under test based on the comparison result between multiple self-discharge current sampling values ​​collected within a preset test period and a preset self-discharge current threshold; the open-circuit voltage decay rate evaluation rule includes: acquiring the open-circuit voltage at the test start point and the open-circuit voltage at the test end point of the cell under test during the preset test period, determining the voltage decay rate of the cell under test based on the rate of voltage drop between the open-circuit voltage at the test start point and the open-circuit voltage at the test end point, and determining the self-discharge test result of the cell under test based on the comparison result between the value of the open-circuit voltage decay rate and the preset open-circuit voltage decay rate threshold; the temperature validity evaluation rule includes: acquiring multiple temperature sampling values ​​of the cell under test, determining the temperature fluctuation based on the multiple temperature sampling values, and determining whether the self-discharge test result of the cell under test is a valid test result based on the comparison result between the temperature fluctuation and the preset temperature fluctuation threshold.

[0014] In a second aspect embodiment, the self-discharge testing device is further configured to acquire the category information and state of charge information of the cell under test, determine the corresponding open-circuit voltage-temperature relationship function set based on the category information of the cell under test, and select a target open-circuit voltage-temperature relationship function corresponding to the state of charge interval from the open-circuit voltage-temperature relationship function set based on the state of charge information; wherein, the open-circuit voltage-temperature relationship function set includes multiple open-circuit voltage-temperature relationship functions respectively corresponding to the state of charge interval; the self-discharge testing device is further configured to acquire the sampled temperature value and open-circuit voltage of the self-discharge testing fixture within a preset time window during the temperature control process performed by the temperature control component on the self-discharge testing fixture. The data processing unit is further configured to obtain the actual temperature change within the preset time window based on the sampled temperature value within the preset time window, and determine the expected temperature change of the cell under test within the preset time window based on the target open-circuit voltage-temperature relationship function and the open-circuit voltage data; the data processing unit is further configured to determine the thermal conductivity matching state between the cell under test and the corresponding self-discharge test fixture based on the difference between the actual temperature change and the expected temperature change; the self-discharge test device is further configured to output abnormal heating state information corresponding to the self-discharge test fixture in response to the thermal conductivity matching state not meeting the preset thermal conductivity matching condition.

[0015] In the second aspect of the embodiment, the data processing unit is further configured to determine the representative temperature value of the current batch based on the sampling temperature values ​​collected by each of the tested cells within a preset test time window; the data processing unit is further configured to map the current temperature correction coefficient of the tested cell based on the category information of the tested cell and the sampling temperature value; the data processing unit is further configured to determine the temperature normalization coefficient corresponding to each tested cell based on the temperature deviation value between the current batch representative temperature value and the sampling temperature value of each tested cell, combined with the temperature correction coefficient of the tested cell; the data processing unit is further configured to normalize the self-discharge current value and open-circuit voltage decay rate in the self-discharge test data corresponding to each tested cell based on the temperature normalization coefficient, to obtain normalized self-discharge test data under the current batch representative temperature value, and to determine the self-discharge test result of each tested cell based on the normalized self-discharge test data.

[0016] As described above, this disclosure provides a self-discharge test fixture and system for cooperating with a self-discharge test device to test a battery cell under test. The fixture includes: a fixture body with a cell test position for accommodating the battery cell under test; a limiting mechanism disposed on the fixture body for limiting the battery cell under test to the cell test position; and at least one conductive mechanism disposed on the fixture body, having a first electrical connection terminal and a second electrical connection terminal electrically connected; the first electrical connection terminal is electrically connected to the self-discharge test device; and the conductive mechanism is configured to move in response to the battery cell under test being loaded into the cell test position, such that the second electrical connection terminal electrically contacts at least one electrode of the battery cell under test, thereby connecting the battery cell under test to the discharge test signal path of the self-discharge test device. This disclosure achieves simultaneous linkage between the loading and positioning of the battery cell under test and the electrical connection of the electrode terminals. After the battery cell under test is limited to the cell test position, the discharge test signal path is connected, which can improve the clamping efficiency of the battery cell during self-discharge testing. Attached Figure Description

[0017] Figure 1 A top view of a self-discharge test fixture according to an embodiment of the present disclosure is shown.

[0018] Figure 2 A side view of a self-discharge test fixture according to an embodiment of the present disclosure is shown.

[0019] Figure 3 A three-dimensional structural schematic diagram of the conductive mechanism in one embodiment of this disclosure is shown.

[0020] Figure 4 A schematic diagram of the structure of the motor drive control conductive mechanism is shown in one embodiment of this disclosure.

[0021] Figure 5A schematic diagram of the self-discharge test system in one embodiment of this disclosure is shown.

[0022] Figure 6 A schematic diagram of the self-discharge testing device in one embodiment of this disclosure is shown. Detailed Implementation

[0023] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the information disclosed herein. This disclosure can also be implemented or applied through other different specific embodiments, and various details in this disclosure can be modified or changed according to different viewpoints and application modules without departing from the spirit of this disclosure. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this disclosure can be combined with each other.

[0024] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings, so that those skilled in the art to which this disclosure pertains can readily implement it. This disclosure may be embodied in many different forms and is not limited to the embodiments described herein.

[0025] In this disclosure, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic represented in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. Furthermore, the specific features, structures, materials, or characteristics represented may be combined in any suitable manner in any one or a group of embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples represented in this disclosure, as well as the features of those different embodiments or examples.

[0026] Furthermore, the terms "first" and "second" are used for illustrative purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the representation of this disclosure, "a set" means two or more, unless otherwise explicitly specified.

[0027] For the purpose of clarity, devices unrelated to the description are omitted, and the same or similar components throughout the specification are given the same reference numerals.

[0028] Throughout this specification, when it is said that a device is "connected" to another device, this includes not only "direct connection" but also "indirect connection" by placing other components in between. Furthermore, when it is said that a device "comprises" a certain constituent element, unless otherwise stated otherwise, this does not exclude other constituent elements, but rather implies that other constituent elements may be included.

[0029] While the terms first, second, etc., are used in some examples herein to refer to various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, first interface and second interface, etc., are used. Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” indicate the presence of the stated feature, step, operation, element, module, item, kind, and / or group, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, modules, items, kinds, and / or groups. The terms “or” and “and / or” as used herein are interpreted as inclusive, or mean any one or any combination thereof. Thus, “A, B, or C” or “A, B, and / or C” means “any one of: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition will only occur if the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0030] The technical terms used herein are for reference only to specific embodiments and are not intended to limit the scope of this disclosure. The singular form used herein includes the plural form unless the statement explicitly indicates otherwise. The word "comprising" as used in this specification means to specify a particular characteristic, region, integer, step, operation, element, and / or component, and does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0031] Although not explicitly defined, all terms, including technical and scientific terms used herein, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms defined in commonly used dictionaries shall be further interpreted as having a meaning consistent with the relevant technical literature and the message of the present disclosure, and shall not be over-interpreted as having an ideal or overly formulaic meaning unless otherwise defined.

[0032] Currently, self-discharge testing equipment typically includes a test fixture for carrying the battery cell under test, probes or conductive terminals connected to the battery cell's terminals, and testing instruments for acquiring voltage and current data. During testing, the battery cell under test is placed in the test fixture, and then the probe is moved to electrically connect the battery cell's terminals to the probe, thus forming a test signal path between the battery cell under test and the self-discharge testing device.

[0033] However, in existing test fixtures, the conductive terminals are usually fixed, requiring operators to perform additional crimping, clamping, or insertion operations after the battery cell under test is loaded to ensure that the probes or conductive terminals contact the electrode ends of the battery cell. The conductive terminals may obstruct the space for the battery cell to enter the test position during loading, requiring additional clearance operations and affecting the ease of handling the battery cell.

[0034] In view of this, the present disclosure provides a self-discharge test fixture, which is used to establish an electrical connection between the conductive terminals on the self-discharge test fixture and the loading action of the battery cell under test during the loading of the battery cell under test at the battery cell test position, and to cooperate with the self-discharge test device to test the battery cell under test, so as to reduce additional crimping or plugging operations on the conductive terminals and improve the connection reliability of the test signal path between the battery cell under test and the self-discharge test device.

[0035] refer to Figure 1 , Figure 1 A top view of a self-discharge test fixture 1000 according to an embodiment of the present disclosure is shown. The self-discharge test fixture 1000 includes a fixture body 100, a limiting mechanism 200, and at least one conductive mechanism 300.

[0036] The fixture body 100 has a cell testing position for accommodating the cell to be tested 400.

[0037] The cell under test, 400, can be a lithium-ion cell, sodium-ion cell, solid-state cell, or other rechargeable battery cell. The cell test position is the location where the testing process for the cell under test, 400, takes place.

[0038] A limiting mechanism 200 is disposed on the fixture body 100. The limiting mechanism 200 is used to limit the battery cell 400 under test to the battery cell test position. Specifically, the limiting mechanism 200 can limit the length, width and / or thickness of the battery cell 400 under test, so that after the battery cell 400 under test is loaded into the battery cell test position, its terminals can be in a position that facilitates contact by the conductive mechanism 300. The limiting mechanism 200 may include a positioning block, a clamping assembly, a limiting boss, a limiting baffle, a limiting groove or other structures that can limit the movement of the battery cell 400 under test relative to the fixture body. The fixture body 100 and the limiting mechanism 200 are preferably made of bakelite, also known as phenolic resin, which has good insulation properties.

[0039] For example, the limiting mechanism 200 further includes a clamping component movable to cover or be removed from the cell test position for clamping the cell under test located at the cell test position. Figure 1 The limiting mechanism 200 shown includes a positioning block 210 and a clamping assembly 220. The positioning block 210 can be fixed to the fixture body 100 by bolts to limit the horizontal movement of the battery cell 400 under test in the battery cell test position. The clamping assembly 220 can also be fixed to the fixture body 100 by bolts to apply a clamping force to the battery cell 400 under test toward the battery cell test position to limit the movement of the battery cell 400 under test relative to the conductive mechanism 300. The clamping assembly 220 includes a clamping plate and a clamping adjustment member. The clamping adjustment member is used to adjust the clamping force applied by the clamping plate to the battery cell 400 under test to adapt to the battery cell 400 under test with different thicknesses. In addition, the clamping plate may also be provided with several buffer pads to prevent the clamping plate from damaging the battery cell.

[0040] In some embodiments, the limiting mechanism 200 includes at least one adjustable limiting member, which is slidably disposed in the limiting adjustment track of the clamp body 100, so as to adjust the effective size of the cell test position by changing the position of the adjustable limiting member relative to the clamp body 100, so that the cell test position can be adapted to the cell 400 under test of different sizes.

[0041] A conductive mechanism 300 is disposed on the fixture body 100. The conductive mechanism 300 has a first electrical connection terminal 311 and a second electrical connection terminal 312 that are electrically connected.

[0042] In some embodiments, reference Figure 2 As shown in the side view of a self-discharge test fixture in one embodiment of this disclosure, a first electrical connection terminal 311 is used for conductive connection to a self-discharge test device, and a second electrical connection terminal 312 is used for electrical contact with at least one electrode of the battery cell 400 under test. Thus, after the second electrical connection terminal 312 contacts the electrode of the battery cell 400 under test, the electrical signal of the battery cell 400 under test is transmitted to the self-discharge test device via the second electrical connection terminal 312, the conductive mechanism 300, and the first electrical connection terminal 311. The conductive mechanism 300 is configured to move to a position where the second electrical connection terminal 312 electrically contacts at least one electrode of the battery cell 400 under test in response to the battery cell 400 being loaded into the battery cell test position, thereby establishing a discharge test signal path from the battery cell 400 under test to the self-discharge test device. Therefore, the conductive mechanism 300 does not rely on the additional operation of pressing the probe to the electrode end, but can move in conjunction with the loading action of the battery cell 400 under test, so that the second electrical connection terminal 312 establishes electrical contact with the electrode end after the battery cell 400 under test is loaded into place.

[0043] In some embodiments, the number of conductive mechanisms 300 can be one or more. When the self-discharge test of the cell under test 400 requires simultaneous connection to both the positive and negative terminals, the self-discharge test fixture 1000 can be configured with two conductive mechanisms 300, which are respectively used to contact the positive and negative terminals of the cell under test 400. Thus, the two terminals of the cell under test 400 can be connected to the self-discharge test device, forming a test circuit between the cell under test 400 and the self-discharge test device. Exemplarily, the conductive mechanisms 300 are configured according to the location of the electrodes, such as... Figure 1 The electrodes of the battery cell shown are arranged on both sides of the battery cell, and the conductive mechanism can be set on both sides of the battery cell.

[0044] In some embodiments, reference Figure 3 A three-dimensional structural schematic diagram of the conductive mechanism in the embodiments of this disclosure is shown, and in conjunction with... Figure 2 A side view of the self-discharge test fixture shows that the conductive mechanism 300 includes a rotating shaft portion 320 disposed on the fixture body 100. Exemplarily, the rotating shaft portion 320 provides a hinged connection position between the rotating member 330 and the fixture body 100, and also serves as the rotation center of the rotating member 330. The rotating member 330 is rotatably connected to the rotating shaft portion 320. Two parts divided by the rotating shaft portion 320 respectively form a pressure-receiving portion 313 and a second electrical connection end 312. The pressure-receiving portion 313 is disposed at the cell test position and located on the movement path of the cell under test 400 being loaded onto the cell test position. When the cell under test 400 is loaded onto the cell test position, the pressure-receiving portion 313 receives pressure from the cell under test 400, with the pressure direction as shown by arrow A, causing the rotating member 330 to rotate around the rotating shaft portion 320, with the rotation direction as shown by arrow B, and driving the second electrical connection end 312 to approach and contact the electrode of the cell under test 400.

[0045] In some examples, the pivot portion 320 includes at least one of a hinge shaft, a pin, and a pivot rod. The rotating component 330 may include at least one of a hinge plate, a rotating block, and a probe mounting base. The pressure-bearing portion may include at least one of a pressure-bearing protrusion, a pressure-bearing plate, and a beveled guide portion. The second electrical connection end 312 may include at least one of a probe, a spring pin, a conductive terminal, and a metal contact. Figure 1As shown, the pivot 320 is implemented as a hinge shaft, and the rotating member 330 is implemented as a hinge plate. Specifically, the rotating member 330 can be constructed as a bent lever structure, with the pivot 320 serving as the fulcrum of the bent lever structure. The pressure-bearing part 313 and the second electrical connection end 312 are respectively formed on both sides of the pivot 320. When the pressure-bearing part 313 is pressed by the battery cell 400 under test, the rotating member 330 rotates around the pivot 320, causing the second electrical connection end 312 to move closer to the electrode of the battery cell 400 under test until contact is made. Thus, the discharge test signal path can be made open under different battery cell structures without affecting the loading action of the battery cell 400 under test.

[0046] In some embodiments, the conductive mechanism 300 and / or the rotating member 330 are adjustable along the rotating shaft portion 320 to allow adjustment so that the electrode terminals of the battery cell 400 under test are located in the rotation path of the second electrical connection terminal 312.

[0047] In some examples, the conductive mechanism 300 may be positionally adjustable relative to the clamp body 100 to allow for positional adjustment of the second electrical connection terminal 312 relative to the electrode end. Exemplarily, the clamp body 100 may be provided with a first guide structure along which the conductive mechanism 300 may move. The first guide structure may be a guide rail, guide groove, guide rod, etc. By adjusting the position of the conductive mechanism 300 on the first guide structure, the rotation path of the second electrical connection terminal 312 can be changed so that the electrode end of the battery cell is properly positioned within the rotation path of the second electrical connection terminal 312.

[0048] In other examples, the position of the second electrical connection end 312 in the rotating member 330 relative to the rotating shaft portion 320 is adjustable, thereby allowing the position of the second electrical connection end 312 relative to the electrode end to be adjustable. Exemplarily, the rotating member 330 may be provided with a second guide structure, which may be a guide opening, an elongated slot, a guide groove, etc. Figure 3 As can be seen, a locking adjustment member 340 may also be provided on the rotating member 330. The locking adjustment member 340 is used to lock or release the second electrical connection end 312. For example, the locking adjustment member 340 may include a locking bolt and a nut. When the locking adjustment member 340 is in the released state, the second electrical connection end 312 can move relative to the rotating shaft portion 320 along the second guide structure. The direction of movement may include... Figure 3The horizontal movement direction is indicated by arrow C1, and the vertical movement direction is indicated by arrow C2. The position of the second electrical connection terminal 312 can be adjusted according to the positional deviation between the second electrical connection terminal 312 and the electrode of the battery cell under test. The relative position between the second electrical connection terminal 312 and the rotating shaft 320 can be adjusted. After the second electrical connection terminal 312 is adjusted to the correct position, it can be locked onto the rotating member 330 by the locking adjustment member 340 to maintain its position. Therefore, after the position of the conductive mechanism 300 is determined, the position of the second electrical connection terminal 312 on the rotating member 330 can be further adjusted so that when the battery cell under test 400 is loaded into the battery cell test position, the rotating member 330 rotates to bring the second electrical connection terminal closer to the electrode of the battery cell until they make contact.

[0049] It can be seen that, through the cooperation of the first guide structure and the second guide structure, the overall position adjustment of the conductive mechanism 300 and the local position adjustment of the second electrical connection terminal 312 can be realized respectively, thereby improving the adaptability of the self-discharge test fixture to different sizes and different electrical end positions.

[0050] In some embodiments, the conductive mechanism 300 further includes a reset elastic element 341, which can be any one of a tension spring, torsion spring, compression spring, or elastic sheet. Figure 1 As can be seen, the example is a tension spring. One end of the reset elastic element 341 is connected to the fixed hook portion 110 fixed on the clamp body 100, and the other end is connected to the locking adjustment element 340 fixed on the conductive mechanism 300. For example, the bolt in the locking adjustment element 340 can be provided with a spring groove so that the spring hook can be fixed in the spring groove of the bolt. When the battery cell 400 under test is loaded into the battery cell test position and presses against the pressure portion, the rotating element 330 rotates around the rotating shaft portion 320, causing the reset elastic element 341 to undergo tensile deformation. After the battery cell 400 under test is displaced from the battery cell test position, the restoring force generated by the reset elastic element 341 acts on the rotating element 330 through the locking adjustment element 340, causing the rotating element 330 to rotate in the opposite direction around the rotating shaft portion 320, and driving the second electrical connection end 312 away from the electrode end of the battery cell 400 under test. There can be two reset elastic elements, symmetrically arranged on both sides of the conductive mechanism 300, for example... Figure 1 Another reset elastic element, symmetrical to the upper reset elastic element 341, is provided below. If it is a torsion spring, it can be sleeved on the rotating shaft.

[0051] In some embodiments, the position adjustment of the conductive mechanism 300 may include a manual adjustment mode and / or an automatic adjustment mode.

[0052] In manual adjustment mode, the conductive mechanism 300 can move relative to the fixture body 100 along a preset adjustment direction. The operator can manually move the conductive mechanism 300 to the target adjustment position according to the model of the battery cell 400 under test, the position of its electrodes, or the scale markings on the fixture body 100, and then fix the conductive mechanism 300 in the target adjustment position using a preset screw locking mechanism or locking mechanism. Thus, the position of the conductive mechanism 300 relative to the electrodes of the battery cell 400 under test can be adjusted through both manual adjustment and mechanical fixing to adapt to the positions of different electrodes on the battery cell.

[0053] In the automatic adjustment mode, the conductive mechanism 300 includes a transport mechanism driven by a motor. The transport mechanism is configured to move the conductive mechanism 300 to a target adjustment position based on position adjustment information in response to the battery cell 400 being loaded into the battery cell test position, so that the second electrical connection terminal 312 can contact the electrode of the battery cell 400 under test.

[0054] The position adjustment information is determined based on the first position information of the electrode in a unified coordinate system and the second position information of the conductive mechanism 300 in a unified coordinate system. The first position information is determined based on the cell structure information of the cell under test 400 and the reference position information of the cell under test 400 in a unified coordinate system. The second position information is determined based on the conductive mechanism in a unified coordinate system. The cell structure information includes: cell size information and the position information of the electrode on the cell.

[0055] In some embodiments, the unified coordinate system can be a planar coordinate system established with the cell test position as the reference. Specifically, the origin of the coordinate system can be any fixed point on the cell test position, and the length and width directions of the self-discharge test fixture can be used as the two coordinate axes of the unified coordinate system. The reference position information of the cell under test 400 in the unified coordinate system can be used to characterize the placement coordinates of the cell under test 400 in the unified coordinate system.

[0056] Specifically, the self-discharge testing device or other control terminal can acquire the cell structure information of the cell under test 400, and combine it with the reference position information of the reference position on the cell under test 400 in a unified coordinate system to determine the first position information of the electrode in the unified coordinate system and the second position information of the conductive mechanism 300 in the unified coordinate system. The cell structure information can be input by the operator through the actual testing interface, or it can be retrieved by the self-discharge testing device 2200 from a pre-stored cell database based on the model of the cell under test 400. The cell structure information may include at least one of the following: length, width, thickness, number of electrode terminals, position information of the electrode terminals relative to the cell under test 400, and electrode extension direction. The reference position information may include the coordinates of at least two reference points on the cell under test 400 in a unified coordinate system.

[0057] In some examples, the first position information can be determined based on visual recognition. For example, the self-discharge test device 2200 or other control terminal can acquire an image of the battery cell 400 under test installed at the battery cell test position through an image acquisition device, and identify the center position and the position of the battery terminal of the battery cell 400 under test, thereby converting the identified battery terminal positions into first position information in a unified coordinate system.

[0058] The self-discharge testing device or other control terminal can also generate position adjustment information based on the position deviation between the first position information and the second position information. This position adjustment information may include pulse signals. For example, when using a servo motor or stepper motor for control, the displacement of the conductive mechanism 300 can be controlled by the number of pulses in the pulse signal, and the displacement speed of the conductive mechanism 300 can be determined by the pulse frequency of the pulse signal. After receiving the position adjustment information, the transport mechanism can adjust the position of the conductive mechanism 300 via the motor, causing the second electrical connection terminal 312 to move into the rotation path where the electrode of the battery cell under test is located.

[0059] For example, Figure 4 A schematic diagram of the motor-driven control conductive mechanism according to an embodiment of the present disclosure is shown. The clamp body 100 may have a guide opening extending along the adjustment direction of the conductive mechanism 300. A transport mechanism 500 driven by a motor 510 may be provided on the bottom side of the clamp body 100. The transport mechanism 500 may include a motor 510, a connecting bracket 520, a movable seat 530, a lead screw 540, and a guide rod 550. The lead screw 540 is drive-connected to the motor 510, the movable seat 530 is drive-fitted to the lead screw 540, and the guide rod 550 is arranged along the extension direction of the lead screw 540 and slides in fit with the movable seat 530. For example, the guide rod 550 and the lead screw 540 are arranged front-to-back in the horizontal direction. When the motor 510 drives the lead screw 540 to rotate, the lead screw 540 drives the movable seat 530 to move along the guide rod 550. The guide rod 550 is used to limit the rotation of the movable seat 530 around the lead screw 540 and to limit the stable movement of the movable seat along a preset adjustment direction. The movable seat 530 is connected to the conductive mechanism 300 via the connecting bracket 520, so as to drive the conductive mechanism 300 to move as a whole relative to the fixture body 100.

[0060] In some embodiments, after the conductive mechanism 300 moves to the target adjustment position, it can be held in the target adjustment position by at least one of the following methods: lead screw self-locking, motor holding torque, and motor brake. Thus, the electrical control adjustment of the rotation path of the second electrical connection terminal 312 can be achieved without manual locking to adapt to the position of the electrodes on different types of battery cells.

[0061] In some embodiments, the conductive mechanism 300 may further include an electrically controlled drive. The electrically controlled drive is used to drive the second electrical connection terminal 312 to contact at least one electrode of the battery cell 400 under test in response to a test start command or a load-in signal, so that the second electrical connection terminal 312 makes electrical contact with the electrode of the battery cell 400 under test. The method by which the second electrical connection terminal 312 moves closer to and contacts the electrode of the battery cell 400 under test may include at least one of linear extension / retraction, lifting / lowering movement, swinging, and rotation.

[0062] In some embodiments, the self-discharge test fixture 1000 may be provided with a loading detection element, which is used to detect whether the battery cell 400 under test is confined to the battery cell test position. The loading detection element can be at least one of a position switch, a photoelectric sensor, a pressure sensor, and a proximity sensor. In response to the loading detection element detecting that the battery cell 400 under test has reached a preset loading position, the electronically controlled drive causes the second electrical connection terminal 312 to move toward the electrode of the battery cell 400 under test and make electrical contact with the electrode. Thus, after the position of the conductive mechanism 300 is adjusted, the contact action between the second electrical connection terminal 312 and the electrode can be completed electronically, thereby further improving the automation level of the self-discharge test fixture 1000.

[0063] This embodiment establishes an electrical connection between the electrode terminals and the self-discharge testing device by providing a conductive mechanism 300 on the fixture body 100 that rotates as the battery cell 400 under test is loaded. Furthermore, by adjusting the position of the conductive mechanism 300 and the partial position of the second electrical connection terminal 312, the adaptability of the self-discharge testing fixture 1000 to different battery cell structures is improved.

[0064] like Figure 5 The diagram shows a schematic of a self-discharge testing system according to an embodiment of the present disclosure. The self-discharge testing system is used to perform self-discharge testing on at least one cell under test on a self-discharge testing fixture.

[0065] At least one clamp receiving cavity 2100 is provided for accommodating the at least one self-discharge test clamp 1000.

[0066] A temperature control component is disposed on each of the self-discharge test fixtures 1000, and is used to collect the sampling temperature value of each of the test cells, and to perform temperature control on the test cells in each of the self-discharge test fixtures 1000 based on the deviation between the sampling temperature value of each test cell and the preset target test temperature.

[0067] In some embodiments, the temperature control instrument 2300, exemplarily, can be powered by a 42V power supply to collect the sampled temperature values ​​of multiple self-discharge test fixtures 1000 and send the sampled temperature values ​​to the self-discharge test device 2200.

[0068] In some examples, the temperature control component may be located on the fixture body 100 and make thermal contact with the cell under test, and be used to perform temperature control on the cell under test on the respective discharge test fixture 1000 in response to the cell under test being confined to the cell test position.

[0069] In some embodiments, the temperature control component includes a temperature acquisition element and a heating element.

[0070] The temperature acquisition element is used to make thermal contact with the battery cell under test to acquire the corresponding sampling temperature value of the battery cell. The temperature acquisition element can be at least one of a thermistor, thermocouple, platinum resistance temperature sensor, or thin-film temperature sensor. Exemplarily, the temperature acquisition element can be disposed on the bottom wall, side wall, clamping plate, thermally conductive contact plate, or other position that can form thermal contact with the battery cell under test at the battery cell test position.

[0071] The heating element is used to make thermal contact with the battery cell under test to perform heating and temperature control on the battery cell under test based on the deviation between the sampled temperature value and the preset target test temperature. The heating element may include an upper heating element and / or a lower heating element. For example, the lower heating element may be disposed on the base plate or bearing surface of the battery cell test position to heat the lower surface of the battery cell under test; the upper heating element may be disposed on the clamping plate or cover plate of the clamping assembly to form thermal contact with the upper surface of the battery cell under test when clamping the battery cell under test. For the battery cell under test with a thinner thickness, a single-sided heating element can be used for temperature control; for the battery cell under test with a thicker thickness, a double-sided heating method with both upper and lower heating elements can be used to improve the uniformity of the overall temperature distribution of the battery cell under test.

[0072] In some embodiments, the self-discharge testing device 2200 is electrically connected to the conductive mechanism on each of the self-discharge testing fixtures 1000, and is used to acquire the sampling temperature value and self-discharge test data corresponding to each self-discharge testing fixture 1000. The self-discharge testing device 2200 can be implemented as an industrial control computer. Exemplarily, the self-discharge testing device 2200 further includes a data acquisition unit 2210. Exemplarily, the data acquisition unit 2210 can be implemented as an independent electrical signal measuring instrument. The data acquisition unit 2210 is used to acquire the self-discharge test data of the corresponding battery cell in response to detecting that the second electrical connection terminal of any self-discharge testing fixture 1000 is electrically connected to the electrode of the corresponding battery cell under test and the sampling temperature value of the battery cell under test reaches a preset target test temperature.

[0073] The self-discharge testing device 2200 further includes a data processing unit, which is used to process the self-discharge test data using preset self-discharge test evaluation rules to determine the self-discharge test result of the cell under test.

[0074] In some embodiments, the self-discharge testing device 2200 may be equipped with self-discharge testing software. The self-discharge testing software provides a practical testing interface through which an operator can configure test configuration parameters for one or more cells under test within the self-discharge testing fixture 1000. The test configuration parameters can be used to define the acquisition conditions, protection conditions, and temperature control conditions during the self-discharge testing process. Exemplarily, the test configuration parameters include at least one of overcurrent threshold, overvoltage threshold, and undervoltage threshold, and may further include at least one of sampling period, test duration, target test temperature, allowable temperature fluctuation range, test channel number, fixture number, cell model information, and cell capacity information.

[0075] In some embodiments, the actual test interface may include a fixture selection area, a parameter configuration area, a test status display area, and a test data display area. The fixture selection area is used to select the self-discharge test fixture 1000 to be tested; the parameter configuration area is used to receive the test configuration parameters of the corresponding self-discharge test fixture 1000; the test status display area is used to display the connection status, temperature control status, acquisition status, and abnormal status of the corresponding self-discharge test fixture 1000; and the test data display area is used to display the self-discharge test data acquired by the acquisition unit.

[0076] In some embodiments, the self-discharge testing device 2200 can bind test configuration parameters to corresponding self-discharge testing fixtures 1000 based on the self-discharge testing fixture identifier. Thus, when multiple self-discharge testing fixtures 1000 are simultaneously connected to the self-discharge testing device 2200, different self-discharge testing fixtures 1000 can perform tests using different test configuration parameters (e.g., different overcurrent thresholds, different overvoltage thresholds) according to the cell model.

[0077] In some embodiments, after receiving a test start command, the self-discharge testing device 2200 can control the acquisition unit and / or temperature control component to perform the test based on the test configuration parameters. Specifically, the self-discharge testing device 2200 can control the temperature control component to control the temperature of the battery cell under test based on the target test temperature; after the sampling temperature value of the battery cell under test reaches the preset target test temperature or falls within the preset temperature allowable range, the self-discharge testing device 2200 controls the acquisition unit to acquire the open-circuit voltage data and / or self-discharge current data of the battery cell under test according to a preset sampling period.

[0078] In some embodiments, the self-discharge testing device 2200 can display the self-discharge test data collected by the acquisition unit on the actual test interface in real time during the test. The self-discharge test data may include at least one of the following: self-discharge test fixture identification, sampling time, open-circuit voltage data, and self-discharge current data; it may also include at least one of the following: sampling temperature value, test channel number, test status identifier, and abnormal prompt information. For example, the actual test interface can display the open-circuit voltage change, self-discharge current change, and temperature change corresponding to each discharge test fixture in the form of a list, graph, or channel card.

[0079] In some embodiments, the self-discharge testing device 2200 can monitor the collected self-discharge test data in real time based on overcurrent threshold, overvoltage threshold, and undervoltage threshold. When the self-discharge current data is greater than the overcurrent threshold, the self-discharge testing device 2200 can output an overcurrent abnormality warning message; when the open-circuit voltage data is greater than the overvoltage threshold, the self-discharge testing device 2200 can output an overvoltage abnormality warning message; when the open-circuit voltage data is less than the undervoltage threshold, the self-discharge testing device 2200 can output an undervoltage abnormality warning message. The abnormality warning messages can be displayed on the actual test interface and can be associated with the corresponding self-discharge test fixture identifier and sampling time, so that the operator can locate the abnormal cell or abnormal test position.

[0080] In some embodiments, the self-discharge testing software can also generate a test record after the test is completed. The test record may include at least one of the following: self-discharge test fixture identifier, cell identifier under test, test configuration parameters, self-discharge test data, abnormal prompt information, and self-discharge test results. This facilitates subsequent quality traceability of the cell under test.

[0081] In some embodiments, the preset self-discharge test evaluation rules include at least one of the following: self-discharge current evaluation rules, open-circuit voltage decay rate evaluation rules, and temperature effectiveness evaluation rules.

[0082] The current evaluation rule includes: determining the self-discharge test result of the cell under test based on the comparison results between multiple self-discharge current sampling values ​​collected within a preset test period and a preset self-discharge current threshold. For example, the self-discharge current sampling value is a microampere or milliampere-level current value collected by the self-discharge testing device 2200 within a preset test period at a preset sampling frequency. The data processing unit can perform mean calculation, peak value extraction, absolute value calculation, or outlier removal processing on multiple self-discharge current sampling values ​​to obtain a current evaluation value representing the self-discharge current level. When the current evaluation value is greater than the preset self-discharge current threshold, it can be determined that the cell under test has a risk of self-discharge abnormality; when the current evaluation value is less than or equal to the preset self-discharge current threshold, it can be determined that the cell under test meets the self-discharge current test requirements.

[0083] For example, if multiple self-discharge current samples are collected within a preset test period, the data processing unit can calculate the average value of these samples. When the average self-discharge current is greater than a preset self-discharge current threshold, a test result indicating an abnormal self-discharge current is output; when the average self-discharge current is less than the preset self-discharge current threshold, a test result indicating that the cell under test meets the self-discharge current condition is output.

[0084] The open-circuit voltage decay rate evaluation rule includes: obtaining the open-circuit voltage at the start of the test and the open-circuit voltage at the end of the test of the cell under test during a preset test period; determining the voltage decay rate of the cell under test based on the rate of voltage drop between the open-circuit voltage at the start of the test and the open-circuit voltage at the end of the test; and determining the self-discharge test result of the cell under test based on the comparison result between the value of the open-circuit voltage decay rate and the preset open-circuit voltage decay rate threshold.

[0085] For example, the test start-point open-circuit voltage is the open-circuit voltage value collected at the beginning of the preset test period, and the test end-point open-circuit voltage is the open-circuit voltage value collected at the end of the preset test period. The data processing unit can use the difference between the test start-point open-circuit voltage and the test end-point open-circuit voltage as the voltage drop, and divide the voltage drop by the duration of the preset test period to obtain the open-circuit voltage decay rate. The open-circuit voltage decay rate can be expressed as: .in, To determine the open-circuit voltage decay rate, the starting open-circuit voltage for the test is... The open-circuit voltage at the end of the test is The preset test period duration is T. When the open-circuit voltage decay rate is greater than the preset open-circuit voltage decay rate threshold, the voltage of the cell under test drops too quickly under static or test conditions, indicating that the cell under test has a risk of abnormal self-discharge; when the open-circuit voltage decay rate does not exceed the preset open-circuit voltage decay rate threshold, it can be determined that the cell under test meets the open-circuit voltage decay test requirements.

[0086] The temperature validity evaluation rules include: acquiring multiple temperature sampling values ​​of the cell under test, determining the temperature fluctuation based on the multiple temperature sampling values, and judging whether the self-discharge test result of the cell under test is a valid test result based on the comparison result between the temperature fluctuation and the preset temperature fluctuation threshold.

[0087] For example, the temperature fluctuation can be the difference between the maximum and minimum temperature values ​​of each cell under test among multiple temperature sampling values ​​during the current self-discharge test. Specifically, multiple temperature sampling values ​​are collected during the current self-discharge test. The data processing unit can determine the maximum and minimum temperature values ​​of each cell under test during the current self-discharge test, and use the difference between the maximum and minimum temperature values ​​as the temperature fluctuation of each cell under test. When the temperature fluctuation is greater than a preset temperature fluctuation threshold, it indicates that the temperature stability of the cell under test is insufficient during the test, and the data of the current self-discharge test may be affected by temperature fluctuations. The data processing unit can mark the current self-discharge test result as an invalid test result, a result to be retested, or a temperature abnormality result. When the temperature fluctuation is less than or equal to the preset temperature fluctuation threshold, it indicates that the cell under test is under relatively stable test temperature conditions, and the current self-discharge test result can be determined as a valid test result.

[0088] In some examples, the data processing unit can first determine whether the test data is valid based on temperature validity criteria. If the test data is valid, it can then determine whether the cell under test is qualified based on self-discharge current criteria and / or open-circuit voltage decay rate criteria. This avoids abnormal self-discharge current or open-circuit voltage decay caused by temperature fluctuations, thereby improving the reliability of self-discharge test results.

[0089] In some embodiments, the self-discharge testing device 2200 is further configured to acquire category information and state of charge information of the battery cell under test. The category information is used to determine the set of open-circuit voltage-temperature relationship functions corresponding to the battery cell under test, and the state of charge information is used to select a target open-circuit voltage-temperature relationship function for the corresponding state of charge range from the set of open-circuit voltage-temperature relationship functions.

[0090] Among them, the set of open-circuit voltage-temperature relationship functions can be obtained through pre-calibration. These functions correspond to multiple open-circuit voltage-temperature relationship functions for different states of charge intervals of the same type of battery cell, and are used to characterize the mapping relationship between the change in open-circuit voltage and the change in battery cell temperature under the corresponding state of charge interval.

[0091] Specifically, a calibration cell of the same model as the cell under test can be selected, and the calibration cell can be adjusted to multiple preset state of charge (SOC) ranges. Within each preset SOC range, the calibration cell can be controlled to be at multiple preset temperature points. Open-circuit voltage data of the calibration cell at each preset temperature point are collected, and based on the temperature change and open-circuit voltage change between adjacent preset temperature points, the open-circuit voltage-temperature relationship function under the corresponding SOC range is fitted.

[0092] The self-discharge testing device 2200 is also used to acquire the sampled temperature value and open-circuit voltage data of the self-discharge testing fixture 1000 within a preset time window during the temperature control process of the temperature control component on the self-discharge testing fixture 1000. The data processing unit determines the actual temperature change based on the sampled temperature value within the preset time window, and determines the expected temperature change of the battery cell under test within the preset time window based on the target open-circuit voltage-temperature relationship function and the open-circuit voltage data. When the difference between the actual temperature change and the expected temperature change of the battery cell exceeds a preset thermal conductivity difference threshold, it is determined that the thermal conductivity matching state between the battery cell under test and the corresponding self-discharge testing fixture 1000 is abnormal.

[0093] In some examples, when the actual temperature change is greater than the expected temperature change of the battery cell, an abnormal message indicating insufficient thermal response of the battery cell is output.

[0094] For example, if the preset thermal conductivity difference threshold is 3 degrees Celsius, and the temperature sampled by the temperature acquisition device is 25 degrees Celsius at the beginning of the preset time window and 35 degrees Celsius at the end of the preset time window, then the actual temperature change is 10 degrees Celsius. However, based on the open-circuit voltage change data within the same preset time window, the expected temperature change of the tested battery cell is calculated to be 2 degrees Celsius using the target open-circuit voltage-temperature relationship function. The difference between the two is 8 degrees Celsius, which is greater than the preset thermal conductivity difference threshold. In this case, it indicates that the self-discharge test fixture 1000 has generated a significant temperature rise, but the tested battery cell itself has not shown a corresponding temperature response. This may be due to abnormalities such as insufficient contact between the tested battery cell and the heating surface, failure of the thermal pad, misalignment of the tested battery cell, or insufficient clamping force of the clamping assembly.

[0095] In other examples, when the actual temperature change is less than the expected temperature change of the battery cell, an abnormal prompt may be output indicating abnormal temperature acquisition, abnormal local heat conduction, or abnormal open-circuit voltage data.

[0096] For example, if the preset thermal conductivity difference threshold is 3 degrees Celsius, and the temperature sampled by the temperature acquisition device rises from 25 degrees Celsius to 27 degrees Celsius within a preset time window, the actual temperature change is 2 degrees Celsius. However, based on the open-circuit voltage change data within the same preset time window, the expected temperature change of the tested cell is calculated to be 10 degrees Celsius using the target open-circuit voltage-temperature relationship function. The difference between the two is 8 degrees Celsius, which is greater than the preset thermal conductivity difference threshold. In this case, it indicates that the open-circuit voltage change of the tested cell reflects a large temperature change, but the temperature change collected by the self-discharge test fixture 1000 is small. This may be due to abnormalities such as poor thermal contact between the temperature acquisition device and the tested cell, the temperature acquisition device not covering the actual heated area, or uneven heating of the tested cell causing the temperature acquisition device to fail to collect the local temperature rise.

[0097] In some embodiments, the data processing unit is further configured to determine a representative temperature value for the current batch based on the sampled temperature values ​​collected by each cell under test within a preset test time window. The representative temperature value for the current batch is used to characterize the unified comparison temperature corresponding to multiple cells under test in the current batch. For example, the data processing unit may determine the representative temperature value for the current batch as the average, median, mode, or target test temperature of the sampled temperature values ​​of multiple cells under test in the current batch within the preset test time window.

[0098] The data processing unit also maps the current temperature correction coefficient of the battery cell under test (BUT) based on its category information and sampled temperature value. The category information can be determined according to the cell model. Different categories of BUT cells exhibit varying sensitivities to temperature changes in their self-discharge current and open-circuit voltage decay rates; therefore, a set of temperature correction parameters corresponding to different BUT cell categories can be pre-established. This set of temperature correction parameters may include a mapping table between temperature ranges and temperature correction coefficients, temperature correction curves, piecewise linear functions, or empirical fitting functions. The data processing unit can retrieve the corresponding temperature correction parameter set based on the BUT cell's category information and map the current temperature correction coefficient based on the sampled temperature value.

[0099] The data processing unit is also used to determine the temperature normalization coefficient corresponding to each battery cell under test based on the temperature deviation between the representative temperature value of the current batch and the sampling temperature value of each battery cell under test, combined with the current temperature correction coefficient of the battery cell under test. For example, if the representative temperature value of the current batch is... The sampling temperature value of a certain battery cell under test is The current temperature correction factor is Then it can be based on the representative temperature value of the current batch. With sampling temperature value Temperature deviation between and the current temperature correction factor The temperature normalization coefficient corresponding to the battery cell under test is determined to be: The temperature normalization coefficient is used to correct the self-discharge test data of the battery cell under test obtained at the actual sampling temperature to the normalized self-discharge test data at the representative temperature value of the current batch, using the temperature normalization formula. The temperature normalization formula can be expressed as follows: .

[0100] For example, the current batch includes a first cell under test, a second cell under test, and a third cell under test, whose sampling temperatures within a preset test time window are 64.5℃, 65℃, and 66℃, respectively. The data processing unit can take the average temperature of the sampling temperatures, 65.16℃, and determine it as the representative temperature value of the current batch.

[0101] A certain type of battery cell under test had a self-discharge current of 12μA at 64.5℃. Pre-calibrated tests showed that for every 1℃ increase in temperature above the representative temperature of the current batch, the self-discharge current increased by approximately 5% relative to that temperature. Therefore, the temperature correction factor can be obtained. The value is 0.05. This is because the representative temperature value of the current batch of the tested battery cell is... With sampling temperature value Temperature deviation between for The data processing unit can correct the 12μA to approximately 12.41μA based on the corresponding temperature normalization coefficient, which will be used as the normalized self-discharge current value at the representative temperature of 65.16℃. Similarly, the data processing unit can also correct the open-circuit voltage decay rate obtained for the tested cell at 64.5℃ to the normalized open-circuit voltage decay rate at the representative temperature of 65.16℃.

[0102] The data processing unit can also determine the self-discharge test results of each cell under test based on normalized self-discharge test data. For example, the data processing unit can compare the normalized self-discharge current value with a preset self-discharge current threshold and the normalized open-circuit voltage decay rate with a preset open-circuit voltage decay rate threshold. When the normalized self-discharge current value is greater than the preset self-discharge current threshold and / or the normalized open-circuit voltage decay rate is greater than the preset open-circuit voltage decay rate threshold, it can be determined that the corresponding cell under test has a risk of abnormal self-discharge. This avoids misjudgment of self-discharge test results due to temperature deviations of the self-discharge test fixture relative to other self-discharge test fixtures.

[0103] like Figure 6 The diagram shows a structural schematic of a self-discharge testing device according to an embodiment of the present disclosure.

[0104] The self-discharge testing device 2200 can be exemplified as a processing terminal, such as a server, desktop computer, laptop computer, tablet computer, industrial control computer, or other terminal.

[0105] The self-discharge testing device 2200 includes a bus 2201, a processor 2202, and a memory 2203. The processor 2202 and the memory 2203 can communicate via the bus 2201. The memory 2203 can store computer programs or instructions. The processor 2202 implements the method flow or function of the previous embodiments by running the computer program or instructions in the memory 2203, for example... Figure 1 .

[0106] Bus 2201 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, although only one thick line is used in the diagram, this does not indicate that there is only one bus or one type of bus.

[0107] In some embodiments, processor 2202 may be implemented as a central processing unit (CPU), microprocessor unit (MCU), system on chip (System on Chip), or field-programmable array (FPGA). Memory 2203 may include volatile memory for temporary data storage during program execution, such as random access memory (RAM).

[0108] The memory 2203 may also include non-volatile memory for data storage, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid-state disk (SSD).

[0109] In some embodiments, the self-discharge testing device 2200 may further include a communicator 2204. The communicator 2204 is used for communication with external devices. In specific examples, the communicator 2204 may include one or more wired and / or wireless communication circuit modules. For example, the communicator 2204 may include one or more of, such as a wired network card, a USB module, a serial interface module, etc. The wireless communication protocols followed by the wireless communication module include, for example, Nearfield communication (NFC) technology, Infrared (IR) technology, Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Time-Division Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), Bluetooth (BT), Global Navigation Satellite System (GNSS), etc., one or more of these.

[0110] This disclosure also provides a computer-readable storage medium storing a computer program or instructions, which, when run, implement the method flow or function of any of the previous embodiments.

[0111] That is, the method steps in the above embodiments are implemented as software or computer code that can be stored in a recording medium (such as CD ROM, RAM, floppy disk, hard disk or magneto-optical disk), or implemented as computer code that is originally stored in a remote recording medium or a non-transitory machine-readable medium and will be stored in a local recording medium after being downloaded via a network, so that the method represented herein can be stored in such software processing on a recording medium using a general-purpose computer, a special processor or programmable or special hardware (such as ASIC or FPGA).

[0112] This disclosure may also provide a computer program product, comprising one or more computer programs or instructions, which, when run, perform all or part of the processes or functions described in this disclosure. The computer program product includes one or more computer programs or instructions.

[0113] Computer programs or instructions can be stored in a readable storage medium or transferred from one readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The readable storage medium can be any available medium capable of access, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video optical disc; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be a volatile or non-volatile storage medium, or it can include both volatile and non-volatile types of storage media.

[0114] In summary, this disclosure provides a self-discharge testing fixture and system for use with a self-discharge testing device to test a battery cell under test. The fixture includes: a fixture body with a cell testing position for accommodating the battery cell under test; a limiting mechanism disposed on the fixture body for limiting the battery cell under test to the cell testing position; and at least one conductive mechanism disposed on the fixture body, having a first electrical connection terminal and a second electrical connection terminal for conductive connection. The first electrical connection terminal is conductively connected to the self-discharge testing device. Furthermore, the conductive mechanism is configured to move in response to the battery cell under test being loaded into the cell testing position, such that the second electrical connection terminal makes electrical contact with at least one electrode of the battery cell under test, thereby conducting a discharge test signal path from the battery cell under test to the self-discharge testing device. This disclosure achieves simultaneous linkage between the loading and positioning of the battery cell under test and the electrical connection of the electrode terminals. After the battery cell under test is limited to the cell testing position, the discharge test signal path is conducted, which can improve the clamping efficiency of the battery cell during the self-discharge testing process.

[0115] The above embodiments are merely illustrative of the principles and effects of this disclosure and are not intended to limit this disclosure. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this disclosure. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this disclosure should still be covered by the protection scope of this disclosure.

Claims

1. A self-discharge testing fixture, characterized in that, Used in conjunction with a self-discharge testing device to test the battery cell under test, including: The fixture body has a cell testing position for accommodating the battery cell under test; A limiting mechanism is provided on the fixture body to limit the battery cell to be tested to the battery cell test position; At least one conductive mechanism is disposed on the fixture body, having a first electrical connection terminal and a second electrical connection terminal that are electrically connected; the first electrical connection terminal is electrically connected to the self-discharge testing device; and the conductive mechanism is configured to move to allow the second electrical connection terminal to electrically contact at least one electrode of the battery cell under test in response to the battery cell being loaded in the battery cell test position, so as to conduct the discharge test signal path from the battery cell under test to the self-discharge testing device.

2. The self-discharge test fixture according to claim 1, characterized in that, The conductive mechanism includes: The pivot section is located on the main body of the clamp; A rotating component is rotatably coupled to the rotating shaft portion, and a pressure-receiving portion and a second electrical connection end are respectively formed in the two parts divided by the rotating shaft portion; The pressure-bearing part is located at the cell test position and on the movement path of the cell under test being loaded onto the cell test position, so as to be pressed on the cell under test to cause the rotating member to rotate so that the second electrical connection end moves closer to the electrical end of the cell until it makes contact.

3. The self-discharge test fixture according to claim 2, characterized in that, The conductive mechanism further includes a reset elastic element, one end of which is connected to and fixed on the clamp body, and the other end is connected to and fixed on the conductive mechanism. The reset elastic element is used to apply a reset force to the conductive mechanism after the cell under test is displaced from the cell test displacement, so as to drive the conductive mechanism to rotate in the opposite direction around the rotating shaft, causing the rotating element to rotate so that the second electrical connection terminal moves away from the electrical end of the cell under test.

4. The self-discharge test fixture according to claim 2, characterized in that, The conductive mechanism and / or the rotating member are adjustable along the shaft to allow adjustment so that the electrode terminals of the battery cell under test are located in the rotational path of the second electrical connection terminal.

5. The self-discharge test fixture according to claim 1, characterized in that, It also includes at least one of the following: (1) The conductive mechanism includes: a motor-driven transport mechanism, the transport mechanism being configured to drive the conductive mechanism to such that the second electrical connection terminal contacts the electrode end based on position adjustment information in response to the battery cell being loaded into the battery cell test position; (2) The limiting mechanism includes at least one adjustable limiting member for adjusting the position to change the size of the cell test position to fit the cell to be tested; (3) The limiting mechanism further includes a clamping component that can be moved to cover or removed from the cell test position for clamping the cell to be tested located at the cell test position.

6. A self-discharge testing system, characterized in that, A system for performing self-discharge testing on at least one cell under test on a self-discharge test fixture as described in any one of claims 1 to 5; the system comprises: At least one clamping cavity for accommodating at least one of the self-discharge test clamps; The temperature control component is used to collect the sampling temperature value of each of the cells under test, and to perform temperature control on each cell under test in the self-discharge test fixture based on the deviation between the sampling temperature value of each cell under test and the preset target test temperature. The self-discharge testing device is electrically connected to the conductive mechanism on each of the self-discharge testing fixtures. The self-discharge testing device includes a data acquisition unit. The data acquisition unit is used to acquire the self-discharge test data corresponding to the battery cell under test in response to detecting that the second electrical connection terminal of any of the self-discharge testing fixtures is electrically connected to the electrode of the corresponding battery cell under test and the sampling temperature value of the battery cell under test reaches the preset target test temperature. The self-discharge testing device further includes a data processing unit, which is used to process the self-discharge test data using preset self-discharge test evaluation rules to determine the self-discharge test result of the cell under test.

7. The self-discharge testing system according to claim 6, characterized in that, The self-discharge testing device provides an actual testing interface through the deployed self-discharge testing software to receive the test configuration parameters of each self-discharge testing fixture, control the acquisition unit and / or the temperature control component to perform the test based on the test configuration parameters, and display the self-discharge test data acquired by the acquisition unit. The test configuration parameters include at least one of overcurrent threshold, overvoltage threshold, and undervoltage threshold, and the self-discharge test data includes at least one of self-discharge test fixture identification, sampling time, open circuit voltage data, and self-discharge current data.

8. The self-discharge testing system according to claim 6, characterized in that, The preset self-discharge test evaluation rules include at least one of the following: self-discharge current evaluation rules, open-circuit voltage decay rate evaluation rules, and temperature effectiveness evaluation rules. The current evaluation rule includes: determining the self-discharge test result of the cell under test based on the comparison results between multiple self-discharge current sampling values ​​collected within a preset test period and a preset self-discharge current threshold. The open-circuit voltage decay rate evaluation rule includes: obtaining the open-circuit voltage at the test start point and the open-circuit voltage at the test end point of the test cell during a preset test period; determining the voltage decay rate of the test cell based on the rate of voltage drop between the open-circuit voltage at the test start point and the open-circuit voltage at the test end point; and determining the self-discharge test result of the test cell based on the comparison result between the value of the open-circuit voltage decay rate and the preset open-circuit voltage decay rate threshold. The temperature validity evaluation rule includes: acquiring multiple temperature sampling values ​​of the cell under test, determining the temperature fluctuation based on the multiple temperature sampling values, and determining whether the self-discharge test result of the cell under test is a valid test result based on the comparison result between the temperature fluctuation and the preset temperature fluctuation threshold.

9. The self-discharge testing system according to claim 6, characterized in that, The self-discharge testing device is further configured to acquire the category information and state of charge information of the cell under test, determine the corresponding open-circuit voltage-temperature relationship function set based on the category information of the cell under test, and select the target open-circuit voltage-temperature relationship function corresponding to the state of charge interval from the open-circuit voltage-temperature relationship function set based on the state of charge information; wherein, the open-circuit voltage-temperature relationship function set includes multiple open-circuit voltage-temperature relationship functions respectively corresponding to the state of charge interval; The self-discharge testing device is also used to acquire the sampled temperature value and open-circuit voltage data of the self-discharge testing fixture within a preset time window during the temperature control process performed by the temperature control component on the self-discharge testing fixture. The data processing unit is also used to obtain the actual temperature change within the preset time window based on the sampled temperature value within the preset time window, and to determine the expected temperature change of the cell under test within the preset time window based on the target open-circuit voltage-temperature relationship function and the open-circuit voltage data. The data processing unit is also used to determine the thermal conduction matching state between the battery cell under test and the corresponding self-discharge test fixture based on the difference between the actual temperature change and the expected temperature change of the battery cell. The self-discharge testing device is also used to output abnormal heating status information corresponding to the self-discharge testing fixture in response to the thermal conduction matching state not meeting the preset thermal conduction matching conditions.

10. The self-discharge testing system according to claim 6, characterized in that, The data processing unit is also used to determine the representative temperature value of the current batch based on the sampling temperature value collected by each of the cells under test within a preset test time window. The data processing unit is also used to map the current temperature correction coefficient of the battery cell under test based on the category information of the battery cell under test and the sampled temperature value. The data processing unit is further configured to determine the temperature normalization coefficient corresponding to each of the tested cells based on the temperature deviation between the representative temperature value of the current batch and the sampling temperature value of each tested cell, combined with the temperature correction coefficient of the tested cell. The data processing unit is further configured to normalize the self-discharge current value and open-circuit voltage decay rate in the self-discharge test data corresponding to each of the tested cells based on the temperature normalization coefficient, to obtain normalized self-discharge test data under the representative temperature value of the current batch, and to determine the self-discharge test result of each tested cell based on the normalized self-discharge test data.

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