Test apparatus and test method

Abstract

The application provides a test device and a test method. The test device comprises a first branch, a second branch and a fifth resistance element. The first branch comprises a first resistance element and a second resistance element, and the common end of the first resistance element and the second resistance element is a first node. The second branch comprises a third resistance element and a fourth resistance element, and the common end of the third resistance element and the fourth resistance element is a second node. One end of the fifth resistance element is electrically connected to the first node, and the other end is electrically connected to the second node. The test device can evaluate the degree of black spot phenomenon and lithium precipitation phenomenon of the battery as the use time increases when the battery is applied to an electronic device, and provide a reference basis for reducing the probability and degree of black spot phenomenon and lithium precipitation phenomenon of the battery as the use time increases when the battery is applied to an electronic device.

Description

Technical Field

[0001] This application relates to the field of testing technology, and in particular to a testing apparatus and a testing method applied to the testing apparatus. Background Technology

[0002] Currently, charging systems used in electronic terminals include processing circuits and batteries. The processing circuits process the charging voltage and current received from the outside and then provide them to the battery. The battery stores electrical energy based on the charging voltage and current. Specifically, the battery includes cells and tabs. The tabs include positive and negative tabs, which provide charging and discharging paths for the cells.

[0003] With the increasing demand for fast charging of batteries, tri-tab batteries have emerged. Compared to bi-tab batteries, tri-tab batteries can form two charging paths and two discharging paths, and can alleviate the heat dissipation pressure on each charging and discharging path, thus possessing stronger fast charging capabilities. However, during use, existing tri-tab batteries are prone to black spots and lithium plating on the surface of their cells. Summary of the Invention

[0004] In view of this, this application provides a testing apparatus and a testing method to evaluate the degree of black spot phenomenon and lithium plating phenomenon that occurs when battery cells are used in electronic devices with increasing usage time. This provides a reference for reducing the probability and extent of black spot phenomenon and lithium plating phenomenon when battery cells are used in electronic devices with increasing usage time. The disclosed technical solution is as follows:

[0005] In a first aspect, this application provides a testing apparatus, comprising:

[0006] Base plate:

[0007] A first branch fixed on the base plate includes a first resistor element and a second resistor element connected in series. The end of the first resistor element away from the second resistor element is electrically connected to a first port of the test device, and the end of the second resistor element away from the first resistor element is electrically connected to a second port of the test device. The common terminal of the first resistor element and the second resistor element is a first node.

[0008] A second branch is fixed on the base plate. The second branch includes a third resistor element and a fourth resistor element connected in series. The end of the third resistor element away from the fourth resistor element is electrically connected to the third port of the test device. The end of the fourth resistor element away from the third resistor element is electrically connected to the fourth port of the test device. The common terminal of the third resistor element and the fourth resistor element is the second node.

[0009] A fifth resistive element is fixed on the base plate, with one end of the fifth resistive element electrically connected to the first node and the other end electrically connected to the second node;

[0010] The first and third ports of the testing device are used for electrical connection with the battery cells, the second and fourth ports of the testing device are used for electrical connection with the power supply, and the second, fourth and fifth resistive elements are adjustable resistive elements.

[0011] The testing apparatus provided in this application, by using different impedance combinations of the second, fourth, and fifth resistive elements, performs a preset number of charge-discharge cycles on different battery cells using a power supply, and then observes the degree of black spots and lithium plating on the surface of each battery cell. Based on the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles on different battery cells with different impedance combinations, it can assess the risk of bias current in the battery cells when they are actually used in electronic devices, especially when the motherboard uses the adjusted impedance combination.

[0012] In one implementation, the impedance range of the second resistive element is 0mΩ to 300mΩ with an accuracy of 0.01mΩ; the impedance range of the fourth resistive element is 0mΩ to 300mΩ with an accuracy of 0.01mΩ; and the impedance range of the fifth resistive element is 0mΩ to 300mΩ with an accuracy of 0.01mΩ. This allows for a large adjustment range and high adjustment accuracy for the second, fourth, and fifth resistive elements, facilitating the selection of the optimal impedance value on the motherboard. This minimizes the probability of black spots and lithium plating appearing on the surface of the battery cell due to improper impedance settings on the motherboard after its application in electronic devices, which could occur with increasing usage time.

[0013] In another implementation, the first resistive element and the third resistive element are adjustable resistive elements, and the testing device further includes:

[0014] A control switch is fixed on the base plate and located between the first resistive element and the first node. One end of the control switch is electrically connected to the end of the first resistive element near the second resistive element, and the other end is electrically connected to the first node. The open end of the first resistive element and the control switch is the third node.

[0015] The third node is electrically connected to the fifth port of the test device, and the second node is also electrically connected to the sixth port of the test device. The fifth port and the sixth port are used for electrical connection to the power supply.

[0016] The testing device provided in this application embodiment can control the control switch to be in the off state, and when the first and third resistive elements are used with different impedance values, it can observe the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles using the power supply. Based on the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles using the power supply under different impedance value combinations, it can assess the risk of bias current in the battery cells when they are actually used in electronic devices and the battery protection board uses the adjusted impedance value combination.

[0017] In another implementation, the control switch is a single-pole single-throw switch to reduce the cost of the control switch.

[0018] In another implementation, the impedance range of the first resistive element is 0mΩ to 300mΩ, with an accuracy of 0.01mΩ; the impedance range of the third resistive element is 0mΩ to 300mΩ, with an accuracy of 0.01mΩ. This allows for a larger resistance adjustment range and higher adjustment accuracy for both the first and second resistive elements, facilitating the selection of the optimal impedance values ​​for the first and second charge / discharge links on the battery protection board. This minimizes the probability of black spots and lithium plating appearing on the battery cell surface due to unreasonable impedance settings of the first and second charge / discharge links on the battery protection board after the cell is actually used in electronic devices, which could occur with increasing usage time.

[0019] Secondly, embodiments of this application also provide a testing method applied to the testing apparatus described in any of the above claims, the method comprising:

[0020] Connect the positive terminal of the battery cell to the first port of the testing device, connect the negative terminal of the battery cell to the third port of the testing device, connect the positive terminal of the power supply to the second port of the testing device, and connect the negative terminal of the power supply to the fourth port of the testing device.

[0021] Adjust the impedance value of at least one of the second, fourth, and fifth resistive elements. Under different combinations of impedance values, perform a preset number of charge-discharge cycles on different cells using a power supply, and then observe the degree of black spots and lithium plating on the surface of each cell.

[0022] The testing apparatus provided in this application, by using different impedance combinations of the second, fourth, and fifth resistive elements, performs a preset number of charge-discharge cycles on different battery cells using a power supply, and then observes the degree of black spots and lithium plating on the surface of each battery cell. Based on the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles on different battery cells with different impedance combinations, it can assess the risk of bias current in the battery cells when they are actually used in electronic devices, especially when the motherboard uses the adjusted impedance combination.

[0023] In one implementation, the method further includes:

[0024] Based on different impedance combinations, the degree of black spots and lithium plating on the surface of each battery cell was determined after performing a preset number of charge-discharge cycles using a power supply. The impedance combination with the least degree of black spots and lithium plating on the battery cell surface after performing a preset number of charge-discharge cycles was selected. This provides the best choice for setting and adjusting the impedance value on the motherboard when the battery cell is actually used in electronic devices, thereby reducing the probability of black spots and lithium plating appearing on the surface of the battery cell as the usage time increases.

[0025] In another implementation, the first resistive element and the third resistive element are adjustable resistive elements, and the test device further includes: a control switch fixed on the base plate and located between the first resistive element and the first node, one end of the control switch being electrically connected to the end of the first resistive element near the second resistive element, and the other end being electrically connected to the first node, wherein the open end of the first resistive element and the control switch is the third node;

[0026] The method also includes:

[0027] Turn on the control switch to put it in the off state;

[0028] Connect the positive terminal of the battery cell to the first port of the testing device, connect the negative terminal of the battery cell to the third port of the testing device, connect the positive terminal of the power supply to the fifth port of the testing device, and connect the negative terminal of the power supply to the sixth port of the testing device.

[0029] Adjust the impedance values ​​of the first and third resistors. Under different impedance value combinations, use the power supply to perform a preset number of charge-discharge cycles on different cells, and observe the degree of black spots and lithium plating on the surface of each cell.

[0030] The testing device provided in this application embodiment can control the control switch to be in the off state, and when the first and third resistive elements are used with different impedance values, it can observe the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles using the power supply. Based on the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles using the power supply under different impedance value combinations, it can assess the risk of bias current in the battery cells when they are actually used in electronic devices and the battery protection board uses the adjusted impedance value combination.

[0031] In another implementation, the method further includes:

[0032] Based on different impedance combinations, the degree of black spots and lithium plating on the surface of each battery cell was determined after performing a preset number of charge-discharge cycles using a power supply. The impedance combination with the lowest degree of black spots and lithium plating on the battery cell surface after performing a preset number of charge-discharge cycles was selected as the first impedance combination. This provides a basis for setting the impedance values ​​of the first and second charge-discharge links on the battery protection board when assembling the cells into a battery. This reduces the probability of black spots and lithium plating appearing on the battery cell surface due to unreasonable impedance values ​​of the first and second charge-discharge links on the battery protection board, which can occur with increasing usage time after the cells are actually used in electronic devices.

[0033] In another implementation, when the control switch is closed, the method further includes:

[0034] Based on the first impedance value combination, the impedance values ​​of the first resistive element and the third resistive element are set.

[0035] The testing apparatus provided in this application embodiment can, under the premise that the first and third resistive elements adopt optimal impedance values, observe the degree of black spots and lithium plating on the surface of each battery cell after performing a preset number of charge-discharge cycles on different battery cells using a power supply when the second, fourth, and fifth resistive elements adopt different impedance value combinations. Thus, based on the degree of black spots and lithium plating on the surface of each battery cell after performing a preset number of charge-discharge cycles on different battery cells using a power supply under different impedance value combinations, the risk of bias current in the battery cell when it is actually applied to electronic devices and the motherboard adopts the adjusted impedance value combination can be assessed.

[0036] In another implementation, the testing method also includes:

[0037] Connect the positive terminal of the battery cell to the first port of the test device, connect the negative terminal of the battery cell to the third port of the test device, connect the positive terminal of the power supply to the second port of the test device, and connect the negative terminal of the power supply to the fourth port of the test device.

[0038] The impedance values ​​of the first resistive element, the second resistive element, the third resistive element, the fourth resistive element, and the fifth resistive element are fixed.

[0039] By using different charging and discharging currents and performing a preset number of charge and discharge cycles on different cells using a power supply, the degree of black spots and lithium plating on the surface of each cell was observed.

[0040] The testing device provided in this application embodiment can also evaluate the risk of bias current in the battery cell during use under different charging and discharging currents, thereby providing a basis for setting the charging and discharging current when the battery cell is actually applied to electronic devices.

[0041] In another implementation, the method further includes:

[0042] Based on the degree of black spots and lithium plating on the surface of each battery cell, the charge-discharge current with the least degree of black spots and lithium plating on the surface of the battery cell after performing a preset number of charge-discharge cycles is selected as the charge-discharge current for subsequent application of the battery cell in electronic devices. This reduces the probability of black spots and lithium plating appearing on the surface of the battery cell as the usage time increases after the battery cell is actually used in electronic devices.

[0043] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of an application scenario for electronic terminals;

[0046] Figure 2 This is a schematic diagram of the structure of a three-pole battery;

[0047] Figure 3 This is a schematic diagram showing the unfolded negative electrode plate in a three-tab battery;

[0048] Figure 4 This is a schematic diagram showing the unfolded positive electrode plate in a three-tab battery;

[0049] Figure 5 This is a schematic diagram of the link impedance when a battery is used in an electronic terminal;

[0050] Figure 6 This is a schematic diagram of the structure of a testing device provided in one embodiment of this application;

[0051] Figure 7 This is a flowchart of a testing method provided in one embodiment of this application;

[0052] Figure 8 This is a flowchart of a testing method provided in another embodiment of this application;

[0053] Figure 9 This is a flowchart of a testing method provided in yet another embodiment of this application;

[0054] Figure 10 This is a schematic diagram of the structure of a testing device provided in another embodiment of this application;

[0055] Figure 11 This is a flowchart of a testing method provided in another embodiment of this application;

[0056] Figure 12 This is a flowchart of a testing method provided in yet another embodiment of this application;

[0057] Figure 13 This is a flowchart of a testing method provided in another embodiment of this application;

[0058] Figure 14 This is a flowchart of a testing method provided in yet another embodiment of this application;

[0059] Figure 15 This is a schematic diagram of the structure of a testing device provided in another embodiment of this application;

[0060] Figure 16 This is a flowchart of a testing method provided in another embodiment of this application;

[0061] Figure 17 This is a flowchart of a testing method provided in yet another embodiment of this application;

[0062] Figure 18 This is a flowchart of a testing method provided in another embodiment of this application. Detailed Implementation

[0063] The terms "first," "second," and "third," etc., used in this application specification, claims, and drawings are used to distinguish different objects, not to limit a specific order.

[0064] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0065] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the related technologies is given first:

[0066] like Figure 1 As shown, Figure 1 This diagram illustrates an application scenario for electronic devices. In daily life, users frequently use their phones, whether commuting or during leisure time, to watch videos, browse the web, play games, and so on. During this process, the device needs to constantly update its display to update images and / or text to meet the user's viewing needs. However, this constant updating consumes a significant amount of power; therefore, the battery performance of an electronic device directly impacts the user experience.

[0067] like Figures 2-4 As shown, Figure 2 This is a schematic diagram of a three-tab battery. Figure 3 This is a schematic diagram showing the unfolded negative electrode plate in a three-tab battery. Figure 4 This is a schematic diagram showing the unfolded positive electrode plate in a three-tab battery. Figures 2-4As can be seen, a three-tab battery consists of a cell and three tabs. The cell is formed by winding a positive electrode and a negative electrode. The first tab, with positive polarity, is located in the uncoated edge area of ​​the positive electrode. The second tab, also with positive polarity, is located in the uncoated center area of ​​the positive electrode. The third tab is located in the uncoated center area of ​​the negative electrode. During operation, the first and third tabs form the first charge / discharge link, and the second and third tabs form the second charge / discharge link. Due to the different positions of the first and second tabs, their impedances differ, resulting in inconsistent charging / discharging currents between the first and second charging / discharging links during cyclic charging and discharging. This long-term inconsistency in charging / discharging currents between the first and second charging / discharging links creates a voltage difference between the first and second tabs, leading to black spots and lithium plating on the cell surface.

[0068] The applicant's research found that when batteries are used in electronic terminals, the impedance of the first charge-discharge link and the second charge-discharge link can be adjusted by setting an adjustable impedance on the motherboard that is electrically connected to the battery. This reduces the difference in impedance between the first charge-discharge link and the second charge-discharge link, thereby alleviating the current bias phenomenon in the tab battery and further alleviating the black spots and lithium plating phenomena that occur in the tab battery during cyclic charging and discharging.

[0069] It should be noted that in practical applications, batteries also include battery protection boards, such as... Figure 5 As shown, Figure 5 This diagram illustrates the link impedance when a battery is used in an electronic terminal. R1 represents the first charge / discharge link impedance on the battery cell, R2 represents the second charge / discharge link impedance on the battery cell, R3 represents the first charge / discharge circuit impedance on the battery protection board, R4 represents the second charge / discharge link impedance on the battery protection board, and R5, R6, and R7 are the adjustment impedances on the main board. Specifically, R5 is the adjustment impedance on the main board used to adjust the first charge / discharge link impedance, R6 is the adjustment impedance on the main board used to adjust the second charge / discharge link impedance, and R7 is the adjustment impedance used to balance the voltages of the first and second charge / discharge links. R1, R2, R3, and R4 are the initial impedance values ​​of the battery at the factory, which can be obtained from the battery manufacturer's instructions. The values ​​of R5, R6, and R7 can be calculated based on the values ​​of R1, R2, R3, and R4.

[0070] While the above methods can alleviate the black spots and lithium plating phenomena in three-tab batteries to some extent, the values ​​of impedances R5, R6, and R7 on the main board are set based on the initial impedance values ​​of the battery cells and battery protection board at the time of manufacture. However, after the battery has been used for a period of time, the resistance values ​​of the first charge / discharge link impedance R1 and the second charge / discharge link impedance R2 in the battery cells will increase with the increase of battery charge / discharge cycles. Moreover, the increase in resistance value ΔR1 of the first charge / discharge link impedance R1 and the increase in resistance value ΔR2 of the second charge / discharge link impedance R2 are different, i.e., ΔR1 ≠ ΔR2. As a result, the resistance values ​​of the first charge / discharge link impedance R5 and the second charge / discharge link impedance R6 on the main board cannot match the required adjustment impedance of the first charge / discharge link and the second charge / discharge link on the battery cell. This causes the battery to experience a current bias phenomenon again during charge and discharge, resulting in black spots and lithium plating on the surface of the battery cells.

[0071] In view of this, embodiments of this application provide a testing apparatus and a testing method applied to the testing apparatus to evaluate the probability and degree of black spot phenomenon and lithium plating phenomenon when battery cells are used in electronic devices, as the usage time increases. This provides a reference for reducing the probability of black spot phenomenon and lithium plating phenomenon when battery cells are used in electronic devices, as the usage time increases. Specifically, as... Figure 6 As shown, the testing apparatus includes:

[0072] Optionally, the base plate 10 is an insulating base plate, meaning that the base plate 10 is made of a non-conductive material.

[0073] A first branch 20 is fixed on the base plate 10. The first branch 20 includes a first resistor element R10 and a second resistor element R20 connected in series. The end of the first resistor element R10 away from the second resistor element R20 is electrically connected to the first port D1 of the test device. The end of the second resistor element R20 away from the first resistor element R10 is electrically connected to the second port D2 of the test device. The common terminal of the first resistor element R10 and the second resistor element R20 is the first node A.

[0074] A second branch 30 is fixed on the base plate 10. The second branch 30 includes a third resistor element R30 and a fourth resistor element R40 connected in series. The end of the third resistor element R30 away from the fourth resistor element R40 is electrically connected to the third port D3 of the test device, and the end of the fourth resistor element R40 away from the third resistor element R30 is electrically connected to the fourth port D4 of the test device. The common terminal of the third resistor element R30 and the fourth resistor element R40 is the second node B.

[0075] A fifth resistor element R50 is fixed on the base plate 10. One end of the fifth resistor element R50 is electrically connected to the first node A, and the other end is electrically connected to the second node B.

[0076] The first port D1 and the third port D3 of the test device are used to electrically connect to the battery cells, the second port D2 and the fourth port D4 of the test device are used to electrically connect to the power supply, and the second resistor R20, the fourth resistor R40 and the fifth resistor R50 are adjustable resistors.

[0077] It should be noted that, in this embodiment, the impedance value of the first resistive element is the impedance value of the first charge-discharge link on the battery protection board in the battery, and the impedance value of the third resistive element is the impedance value of the second charge-discharge link on the battery protection board in the battery.

[0078] Specifically, in one embodiment of this application, the first port of the testing device is electrically connected to the positive terminal of the battery cell, the third port is electrically connected to the negative terminal of the battery cell, the second port is electrically connected to the positive terminal of the power supply, and the fourth port is electrically connected to the negative terminal of the power supply; in another embodiment of this application, the first port of the testing device is electrically connected to the negative terminal of the battery cell, the third port is electrically connected to the positive terminal of the battery cell, the second port is electrically connected to the negative terminal of the power supply, and the fourth port is electrically connected to the positive terminal of the power supply. This application does not limit the specific configuration, but rather depends on the specific circumstances.

[0079] The following description uses an example where the first port of the test device is electrically connected to the positive terminal of the battery cell, the third port is electrically connected to the negative terminal of the battery cell, the second port is electrically connected to the positive terminal of the power supply, and the fourth port is electrically connected to the negative terminal of the power supply to illustrate the test device provided in this application.

[0080] In specific work, such as Figure 7 As shown, in this embodiment, the test method for assessing the bias current risk of a battery cell using this test device includes:

[0081] S101: Connect the positive terminal of the battery cell to the first port of the test device, connect the negative terminal of the battery cell to the third port of the test device, connect the positive terminal of the power supply to the second port of the test device, and connect the negative terminal of the power supply to the fourth port of the test device.

[0082] S102: Adjust the impedance values ​​of the second, fourth, and fifth resistive elements. Under different impedance value combinations, after performing a preset number of charge-discharge cycles on different cells using the power supply, observe the degree of black spots and lithium plating on the surface of each cell. This allows for the assessment of the risk of bias current in the cell under the impedance value combination based on the degree of black spots and lithium plating on the cell surface.

[0083] Optionally, in one embodiment of this application, the following continues... Figure 7 As shown, the method also includes:

[0084] S103: Based on the degree of black spot phenomenon and lithium plating phenomenon on the surface of each cell, assess the risk of bias current of the cell under this impedance value combination.

[0085] Therefore, the testing device provided in this application embodiment, by using different impedance combinations of the second, fourth, and fifth resistive elements and performing a preset number of charge-discharge cycles on different battery cells using a power supply, observes the degree of black spots and lithium plating on the surface of each battery cell. Based on the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles on different battery cells using a power supply under different impedance combinations, it can assess the risk of bias current in the battery cells when they are actually used in electronic devices and the motherboard uses the adjusted impedance combination.

[0086] Specifically, in one embodiment of this application, the power source is a charge and discharge test cabinet, but this application does not limit it and it depends on the specific circumstances.

[0087] Optionally, in one embodiment of this application, such as Figure 8 As shown, the test method also includes:

[0088] S104: Based on different impedance combinations, after performing a preset number of charge-discharge cycles on different battery cells using a power supply, the degree of black spots and lithium plating on the surface of each battery cell is determined. The impedance combination with the least degree of black spots and lithium plating on the surface of the battery cell after performing a preset number of charge-discharge cycles is selected. This provides the best choice for setting and adjusting the impedance value on the motherboard when the battery cell is actually used in electronic devices, thereby reducing the probability of black spots and lithium plating appearing on the surface of the battery cell as the usage time increases.

[0089] Specifically, based on the above embodiments, in one embodiment of this application, such as Figure 9 As shown, the test method includes:

[0090] S111: Fix the impedance value of the first resistor element to the impedance value of the first charge-discharge link on the battery protection board, fix the third resistor element to the impedance value of the second charge-discharge link on the battery protection board, and connect the positive terminal of the power supply to the second port of the test device and the negative terminal of the power supply to the fourth port of the test device.

[0091] S112: Take a battery cell, denoted as the first battery cell, connect the positive terminal of the first battery cell to the first port of the test device, connect the negative terminal of the first battery cell to the third port of the test device, and adjust the impedance value of the second resistor element to the first preset impedance value, the impedance value of the fourth resistor element to the second preset impedance value, and the impedance value of the fifth resistor element to the third preset impedance value.

[0092] S113: Turn on the power, and after performing a preset number of charge and discharge cycles on the first cell, remove the first cell and observe the degree of black spots and lithium plating on the surface of the first cell.

[0093] S114: Take a new battery cell, designated as the second battery cell, connect the positive terminal of the second battery cell to the first port of the test device, connect the negative terminal of the second battery cell to the third port of the test device, and adjust the impedance value of at least one of the second, fourth, and fifth resistive elements to a first amplitude along the first direction. Turn on the power supply and use the power supply to perform a preset number of charge-discharge cycles on the second battery cell. Then, remove the second battery cell and observe the degree of black spots and lithium plating on the surface of the second battery cell.

[0094] S115: If the degree of black spots and lithium plating on the surface of the second cell is less than that on the surface of the first cell, the current second cell is treated as the first cell, and S114 is executed again until the degree of black spots and lithium plating on the surface of the second cell is more severe than that on the surface of the first cell. When the degree of black spots and lithium plating on the surface of the cell is determined to be the least severe, the impedance values ​​corresponding to the second, fourth, and fifth resistor elements are used as the impedance value combination with the least severe black spots and lithium plating on the surface of the cell after performing a preset number of charge-discharge cycles on the cell. Otherwise, S116 is executed.

[0095] S116: Take a new battery cell, designated as the third battery cell, connect the positive terminal of the third battery cell to the first port of the test device, connect the negative terminal of the third battery cell to the third port of the test device, and adjust the impedance value of at least one of the second, fourth, and fifth resistive elements to a first amplitude along the second direction. Turn on the power supply and use the power supply to perform a preset number of charge-discharge cycles on the third battery cell. After that, remove the third battery cell and observe the degree of black spots and lithium plating on the surface of the third battery cell. The second direction is opposite to the first direction.

[0096] S117: If the degree of black spots and lithium plating on the surface of the third cell is less than that on the surface of the first cell, the current third cell is treated as the first cell, and S116 is executed again until the degree of black spots and lithium plating on the surface of the third cell is more severe than that on the surface of the first cell. When the degree of black spots and lithium plating on the surface of the cell is determined to be the least severe, the impedance values ​​corresponding to the second, fourth, and fifth resistor elements are used as the impedance value combination with the least severe black spots and lithium plating on the surface of the cell after performing a preset number of charge-discharge cycles on the cell. If the degree of black spots and lithium plating on the surface of the third cell is more severe than that on the surface of the first cell, the first, second, and third preset impedance values ​​are determined as the impedance value combination with the least severe black spots and lithium plating on the surface of the cell after performing a preset number of charge-discharge cycles on the cell.

[0097] It should be noted that, in practical applications, the motherboard is equipped with a control circuit for controlling the charging and discharging process of the battery. Optionally, in this embodiment, the first preset impedance value, the second preset impedance value, and the third preset impedance value are determined based on the impedance of the control circuit on the motherboard. However, this application does not limit this, and it depends on the specific circumstances.

[0098] It should also be noted that when the first direction is increasing, the second direction is decreasing, and when the first direction is decreasing, the second direction is increasing. Furthermore, the embodiments of this application do not limit the first magnitude; it depends on the specific circumstances.

[0099] Specifically, in one embodiment of this application, the impedance value of the second resistive element is in the range of 0mΩ to 300mΩ with an accuracy of 0.01mΩ; the impedance value of the fourth resistive element is in the range of 0mΩ to 300mΩ with an accuracy of 0.01mΩ; and the impedance value of the fifth resistive element is in the range of 0mΩ to 300mΩ with an accuracy of 0.01mΩ. This allows for a large adjustment range and high adjustment accuracy for the second, fourth, and fifth resistive elements, facilitating the selection of the optimal impedance value on the motherboard. This minimizes the probability of black spots and lithium plating appearing on the surface of the battery cell due to improper impedance settings on the motherboard after its actual application in electronic devices, which could occur with increasing usage time.

[0100] It should be noted that the test environment temperature range of the test device provided in this application embodiment is -20 to 65°C, which can be applied to the bias current risk assessment of the battery cell under various ambient temperatures.

[0101] It should also be noted that in practical applications, in addition to the impedance setting on the motherboard affecting the probability and degree of black spots and lithium plating on the cell surface, the first charge / discharge link impedance value and the second charge / discharge link impedance value on the battery protection board also affect the probability and degree of black spots and lithium plating on the cell surface.

[0102] Based on this, in one embodiment of this application, in addition to any of the above embodiments, the first resistive element and the third resistive element are also adjustable resistive elements. Optionally, in this embodiment, as shown... Figure 10 As shown, the testing apparatus further includes:

[0103] A control switch 40 is fixed on the base plate 10 and located between the first resistive element R10 and the first node A. One end of the control switch 40 is electrically connected to the end of the first resistive element R10 near the second resistive element R20, and the other end is electrically connected to the first node A. The exposed ends of the first resistive element R10 and the control switch 40 are the third node C. It should be noted that, in this embodiment, the third node C is electrically connected to the fifth port D5 of the testing device, and the second node B is also electrically connected to the sixth port D6 of the testing device. The fifth port D5 and the sixth port D6 are used for electrical connection to a power supply. Optionally, the control switch is a single-pole single-throw switch to reduce the cost of the control switch, but this application does not limit it and the specific choice depends on the situation.

[0104] Specifically, based on the above embodiments, in one embodiment of this application, the fifth port is used to be electrically connected to the positive terminal of the power supply, and the sixth port is used to be electrically connected to the negative terminal of the power supply. In another embodiment of this application, the fifth port is used to be electrically connected to the negative terminal of the power supply, and the sixth port is used to be electrically connected to the positive terminal of the power supply. This application does not limit this, and it depends on the specific circumstances.

[0105] The following description uses the example of the fifth port being used for electrical connection to the positive terminal of the power supply and the sixth port being used for electrical connection to the negative terminal of the power supply to illustrate the testing device provided in the embodiments of this application.

[0106] like Figure 11 As shown, in this embodiment, the test method for assessing the bias current risk of a battery cell using this test device includes:

[0107] S201: Continue as follows Figure 10 As shown, turn the control switch on, so that the control switch is in the off state;

[0108] S202: Connect the positive terminal of the battery cell to the first port of the test device, the negative terminal of the battery cell to the third port of the test device, the positive terminal of the power supply to the fifth port of the test device, and the negative terminal of the power supply to the sixth port of the test device.

[0109] S203: Adjust the impedance values ​​of the first and third resistors. Under different impedance value combinations, after performing a preset number of charge-discharge cycles on different cells using the power supply, observe the degree of black spots and lithium plating on the surface of each cell. Based on the degree of black spots and lithium plating on the surface of each cell, assess the risk of bias current in the cell under the impedance value combination.

[0110] Optionally, in one embodiment of this application, the following continues... Figure 11 As shown, the method also includes:

[0111] S204: Based on the degree of black spot phenomenon and lithium plating phenomenon on the surface of each cell, assess the risk of bias current of the cell under this impedance value combination.

[0112] Therefore, the testing device provided in this application embodiment can, by controlling the control switch to be in the off state, and using different impedance combinations of the first and third resistive elements, observe the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles using the power supply on different battery cells. Based on the degree of black spots and lithium plating on the surface of the battery cells after performing a preset number of charge-discharge cycles using the power supply under different impedance combinations, the risk of bias current in the battery cells when they are actually used in electronic devices can be assessed.

[0113] Optionally, in one embodiment of this application, such as Figure 12 As shown, the test method also includes:

[0114] S205: Based on the degree of black spot phenomenon and lithium plating on the surface of each cell under different impedance value combinations, the impedance value combination with the mildest degree of black spot phenomenon and lithium plating on the cell surface after performing a preset number of charge-discharge cycles is selected as the first impedance value combination. This provides a basis for setting the impedance values ​​of the first charge-discharge link and the second charge-discharge link on the battery protection board when the cells are subsequently assembled into a battery. This reduces the probability of black spot phenomenon and lithium plating on the cell surface due to unreasonable impedance values ​​of the first charge-discharge link and the second charge-discharge link on the battery protection board after the cells are actually used in electronic devices, which would occur with increasing usage time.

[0115] Specifically, in one embodiment of this application, such as Figure 13As shown, the test method includes:

[0116] S211: Connect the positive terminal of the power supply to the fifth port D5 of the test device, and connect the negative terminal of the power supply to the sixth port D6 of the test device.

[0117] S212: Take a battery cell, denoted as the fourth battery cell, connect the positive terminal of the fourth battery cell to the first port D1 of the test device, connect the negative terminal of the fourth battery cell to the third port D3 of the test device, and adjust the impedance value of the first resistor R10 to the fourth preset impedance value and the impedance value of the third resistor R30 to the fifth preset impedance value.

[0118] S213: Turn on the power and use the power to perform a preset number of charge and discharge cycles on the fourth cell. Then, remove the fourth cell and observe the degree of black spots and lithium plating on the surface of the fourth cell.

[0119] S214: Take a new battery cell, designated as the fifth battery cell, connect the positive terminal of the fifth battery cell to the first port D1 of the test device, connect the negative terminal of the fifth battery cell to the third port D3 of the test device, and adjust the impedance value of at least one of the first resistor element R10 and the third resistor element R30 to a second amplitude along the first direction. Turn on the power supply and use the power supply to perform a preset number of charge and discharge cycles on the fifth battery cell. After that, remove the fifth battery cell and observe the degree of black spots and lithium plating on the surface of the fifth battery cell.

[0120] S215: If the degree of black spots and lithium plating on the surface of the fifth cell is less than that on the surface of the fourth cell, the current fifth cell is treated as the fourth cell, and S214 is executed again until the degree of black spots and lithium plating on the surface of the fifth cell is more severe than that on the surface of the first cell. When the degree of black spots and lithium plating on the surface of the cell is determined to be the least severe, the impedance values ​​corresponding to the first and third resistor elements are used as the impedance value combination with the least severe black spots and lithium plating on the surface of the cell after performing a preset number of charge and discharge cycles on the cell. Otherwise, S216 is executed.

[0121] S216: Take a new battery cell, denoted as the sixth battery cell, connect the positive terminal of the sixth battery cell to the first port of the test device, connect the negative terminal of the sixth battery cell to the third port of the test device, and adjust the impedance value of at least one of the first and third resistive elements to a second amplitude along the second direction. Turn on the power supply and use the power supply to perform a preset number of charge and discharge cycles on the sixth battery cell. After that, remove the sixth battery cell and observe the degree of black spot phenomenon and lithium plating phenomenon on the surface of the sixth battery cell. The second direction is opposite to the first direction.

[0122] S217: If the degree of black spots and lithium plating on the surface of the sixth cell is less than that on the surface of the fourth cell, the current sixth cell is treated as the fourth cell, and S216 is executed again until the degree of black spots and lithium plating on the surface of the sixth cell is more severe than that on the surface of the fourth cell. When the degree of black spots and lithium plating on the cell surface is determined to be the least severe, the impedance values ​​corresponding to the first and third resistor elements are used as the impedance value combination with the least severe black spots and lithium plating on the cell surface after performing a preset number of charge-discharge cycles on the cell. If the degree of black spots and lithium plating on the surface of the sixth cell is more severe than that on the surface of the fourth cell, the fourth and fifth preset impedance values ​​are determined as the impedance value combination with the least severe black spots and lithium plating on the cell surface after performing a preset number of charge-discharge cycles on the cell.

[0123] It should be noted that in practical applications, the battery protection board is equipped with a protection circuit to prevent overcharging, over-discharging, or short circuits during the charging and discharging process of the battery. Optionally, the fourth preset impedance value and the fifth preset impedance value are determined based on the impedance value of the protection circuit on the battery protection board. However, this application does not limit this, and it depends on the specific circumstances.

[0124] It should also be noted that when the first direction is increasing, the second direction is decreasing, and when the first direction is decreasing, the second direction is increasing. Furthermore, the embodiments of this application do not limit the second magnitude; it depends on the specific circumstances.

[0125] Specifically, in one embodiment of this application, the impedance value of the first resistive element is in the range of 0mΩ to 300mΩ, with an accuracy of 0.01mΩ; the impedance value of the third resistive element is in the range of 0mΩ to 300mΩ, with an accuracy of 0.01mΩ. This allows for a large adjustment range and high adjustment accuracy for the first and second resistive elements, facilitating the selection of the optimal impedance values ​​for the first and second charge / discharge links on the battery protection board. This minimizes the probability of black spots and lithium plating appearing on the surface of the battery cell due to unreasonable settings of the impedance values ​​of the first and second charge / discharge links on the battery protection board after the cell is actually used in electronic devices, which could lead to increased usage time.

[0126] Based on the above embodiments, in one embodiment of this application, such as Figure 14 As shown, the method also includes:

[0127] S301: As Figure 15As shown, when the control switch 40 is closed, the closed switch is in the conducting state, maintaining the positive terminal of the battery cell electrically connected to the first port of the test device, the negative terminal of the battery cell electrically connected to the third port of the test device, and then the positive terminal of the power supply is electrically connected to the second port of the test device, no longer electrically connected to the fifth port, and the negative terminal of the power supply is electrically connected to the fourth port of the test device, no longer electrically connected to the sixth port.

[0128] S302: Based on the first impedance value combination, set the impedance values ​​of the first resistive element and the third resistive element;

[0129] S303: Adjust the impedance values ​​of the second, fourth, and fifth resistive elements. Under different impedance value combinations, after performing a preset number of charge-discharge cycles on different cells using the power supply, observe the degree of black spots and lithium plating on the surface of each cell. Based on the degree of black spots and lithium plating on the surface of each cell, assess the risk of bias current in the cell under the impedance value combination.

[0130] Optionally, in one embodiment of this application, the following continues... Figure 14 As shown, the method also includes:

[0131] S304: Based on the degree of black spot phenomenon and lithium plating phenomenon on the surface of each cell, assess the risk of bias current of the cell under this impedance value combination.

[0132] Therefore, the testing device provided in this application embodiment can, under the premise that the first and third resistive elements adopt optimal impedance values, observe the degree of black spots and lithium plating on the surface of each battery cell after performing a preset number of charge-discharge cycles on different battery cells using power supply when the second, fourth, and fifth resistive elements adopt different impedance value combinations. Thus, based on the degree of black spots and lithium plating on the surface of each battery cell after performing a preset number of charge-discharge cycles on different battery cells using power supply under different impedance value combinations, the risk of bias current in the battery cell when it is actually applied to electronic devices and the motherboard adopts the adjusted impedance value combination can be assessed.

[0133] Optionally, in one embodiment of this application, such as Figure 16 As shown, the test method also includes:

[0134] S305: Based on different impedance value combinations, after performing a preset number of charge-discharge cycles on different battery cells using a power supply, the degree of black spots and lithium plating on the surface of each battery cell is determined. The impedance value combination with the least degree of black spots and lithium plating on the surface of the battery cell after performing a preset number of charge-discharge cycles is selected as the second impedance value combination. This provides the best choice for setting and adjusting the impedance value on the motherboard when the battery cell is actually used in electronic devices, thereby reducing the probability of black spots and lithium plating appearing on the surface of the battery cell as the usage time increases.

[0135] Specifically, in one embodiment of this application, the impedance value of the second resistive element is in the range of 0mΩ to 300mΩ with an accuracy of 0.01mΩ; the impedance value of the fourth resistive element is in the range of 0mΩ to 300mΩ with an accuracy of 0.01mΩ; and the impedance value of the fifth resistive element is in the range of 0mΩ to 300mΩ with an accuracy of 0.01mΩ. This allows for a large adjustment range and high adjustment accuracy for the second, fourth, and fifth resistive elements, facilitating the selection of the optimal impedance value on the motherboard. This minimizes the probability of black spots and lithium plating appearing on the surface of the battery cell due to improper impedance settings on the motherboard after its actual application in electronic devices, which could occur with increasing usage time.

[0136] It should be noted that in practical applications, in addition to the settings of the adjustable impedance value on the motherboard and the first and second charge / discharge link impedance values ​​on the battery protection board affecting the probability and degree of black spots and lithium plating on the cell surface, the magnitude of the battery's charge / discharge current also affects the probability and degree of black spots and lithium plating on the cell surface.

[0137] Based on this, and on any of the above embodiments, such as Figure 17 As shown, the test method also includes:

[0138] S401: Connect the positive terminal of the battery cell to the first port of the test device, connect the negative terminal of the battery cell to the third port of the test device, connect the positive terminal of the power supply to the second port of the test device, and connect the negative terminal of the power supply to the fourth port of the test device.

[0139] S402: Fix the impedance values ​​of the first resistive element, the second resistive element, the third resistive element, the fourth resistive element, and the fifth resistive element.

[0140] S403: Using different charge and discharge currents, after performing a preset number of charge and discharge cycles on different cells using the power supply, observe the degree of black spots and lithium plating on the surface of each cell, so as to assess the risk of bias current of the cell under the charge and discharge current based on the degree of black spots and lithium plating on the surface of each cell.

[0141] Optionally, in one embodiment of this application, the following continues... Figure 17 As shown, the method also includes:

[0142] S404: Based on the degree of black spot phenomenon and lithium plating phenomenon on the surface of each cell, assess the risk of bias current of the cell under this charge and discharge current.

[0143] Therefore, the testing device provided in this application embodiment can also evaluate the risk of bias current in the battery cell during use under different charging and discharging currents, thereby providing a basis for setting the charging and discharging current when the battery cell is actually used in electronic devices.

[0144] Optionally, in one embodiment of this application, such as Figure 18 As shown, the test method also includes:

[0145] Based on the degree of black spots and lithium plating on the surface of each battery cell, the charge-discharge current with the least degree of black spots and lithium plating on the surface of the battery cell after performing a preset number of charge-discharge cycles is selected as the charge-discharge current for subsequent application of the battery cell in electronic devices. This reduces the probability of black spots and lithium plating appearing on the surface of the battery cell as the usage time increases after the battery cell is actually used in electronic devices.

[0146] The following describes, with reference to a specific embodiment, the process of selecting the charge-discharge current with the least degree of black spot phenomenon and lithium plating phenomenon on the surface of the battery cell after performing a preset number of charge-discharge cycles on the battery cell in the test method provided in this application embodiment.

[0147] Specifically, in one embodiment of this application, the saturation voltage of the battery cell is 4.45V, and the test method includes:

[0148] S501: Connect the positive terminal of the battery cell to the first port of the test device, connect the negative terminal of the battery cell to the third port of the test device, connect the positive terminal of the power supply to the second port of the test device, and connect the negative terminal of the power supply to the fourth port of the test device.

[0149] S502: Charge the battery cell with a constant current of 3C until the battery cell voltage reaches 4.1V, then charge the battery cell with a constant current of 2C until the battery cell voltage reaches 4.2V, then charge the battery cell with a constant current of 1.5C until the battery cell voltage reaches 4.3V, then charge the battery cell with a constant current of 0.7C until the battery cell voltage reaches 4.45V, and finally charge the battery cell with a constant voltage of 4.45V until the battery cell charging current drops to 0.025C, completing the charging process. Then discharge the battery cell with a constant current of 0.7C until the battery cell voltage drops to 3.0V, completing one charge-discharge cycle.

[0150] S503: Execute S502 a preset number of times, remove the battery cell, and observe the degree of black spots and lithium plating on the surface of the battery cell;

[0151] S504: Maintain the positive terminal of the power supply connected to the second port of the test device, and the negative terminal of the power supply connected to the fourth port of the test device. Take a new battery cell, connect the positive terminal of the battery cell to the first port of the test device, and the negative terminal of the battery cell to the third port of the test device.

[0152] S505: Charge the battery cell with a constant current of 2.7C until the battery cell voltage reaches 4.1V or less. Then charge the battery cell with a constant current of 1.8C until the battery cell voltage reaches 4.2V or less. Then charge the battery cell with a constant current of 1.3C until the battery cell voltage reaches 4.3V or less. Then charge the battery cell with a constant current of 0.7C until the battery cell voltage reaches 4.45V. Finally, charge the battery cell with a constant voltage of 4.45V until the battery cell charging current drops to 0.025C, and the charging is complete. Then discharge the battery cell with a constant current of 0.7C or less until the battery cell voltage drops to 3.0V, and the discharge is complete, completing one charge-discharge cycle.

[0153] S506: Execute S505 a preset number of times, remove the battery cell, and observe the degree of black spots and lithium plating on the surface of the battery cell;

[0154] S507: Compare the degree of black spots and lithium plating on the cell surface in S503 with the degree of black spots and lithium plating on the cell surface in S505. If the degree of black spots and lithium plating on the cell surface in S505 is less severe than that in S503, keep the positive terminal of the power supply connected to the second port of the test device and the negative terminal of the power supply connected to the fourth port of the test device. Take a new cell, connect the positive terminal of the cell to the first port of the test device and the negative terminal of the cell to the third port of the test device, and execute S508. Otherwise, execute S511.

[0155] S508: Charge the battery cell with a constant current of 2.6C until the battery cell voltage reaches 4.1V or less. Then charge the battery cell with a constant current of 1.6C until the battery cell voltage reaches 4.2V or less. Then charge the battery cell with a constant current of 1.1C until the battery cell voltage reaches 4.3V or less. Then charge the battery cell with a constant current of 0.7C until the battery cell voltage reaches 4.45V. Finally charge the battery cell with a constant voltage of 4.45V until the battery cell charging current drops to 0.025C, and the charging is complete. Then discharge the battery cell with a constant current of 0.7C or less until the battery cell voltage drops to 3.0V, and the discharge is complete, completing one charge-discharge cycle.

[0156] S509: Repeat S508 a preset number of times, remove the battery cell, and observe the degree of black spots and lithium plating on the surface of the battery cell;

[0157] S510: Compare the degree of black spots and lithium plating on the surface of the cells in S505 and S509. If the degree of black spots and lithium plating on the surface of the cells in S509 is less severe than that in S505, maintain the positive terminal of the power supply connected to the second port of the test device and the negative terminal connected to the fourth port of the test device. Take a new cell, connect its positive terminal to the first port of the test device, and its negative terminal to the fourth port of the test device. The third port is set, and the charging current and / or discharging current of the cell are further reduced. The new cell is subjected to a preset number of charge-discharge cycles. The degree of black spot phenomenon and lithium plating phenomenon on the surface of the cell are observed. This process is repeated until the charging current and discharging current corresponding to the lightest degree of black spot phenomenon and lithium plating phenomenon on the surface of the cell are found after performing a preset number of charge-discharge cycles on the cell. These currents are then used as the charging and discharging currents for the subsequent application of the cell in electronic devices. This reduces the probability of black spot phenomenon and lithium plating phenomenon appearing on the surface of the cell as the usage time increases after the cell is actually applied to electronic devices.

[0158] S511: Charge the battery cell with a constant current of 3.2C until the battery cell voltage reaches 4.1V or greater. Then charge the battery cell with a constant current of 2.2C until the battery cell voltage reaches 4.2V or greater. Then charge the battery cell with a constant current of 1.7C until the battery cell voltage reaches 4.3V or greater. Then charge the battery cell with a constant current of 0.7C until the battery cell voltage reaches 4.45V. Finally, charge the battery cell with a constant voltage of 4.45V until the battery cell charging current drops to 0.025C, and the charging is complete. Then discharge the battery cell with a constant current of 0.7C or greater until the battery cell voltage drops to 3.0V, and the discharge is complete, completing one charge-discharge cycle.

[0159] S512: Execute S511 a preset number of times, remove the battery cell, and observe the degree of black spots and lithium plating on the surface of the battery cell;

[0160] S513: Compare the degree of black spots and lithium plating on the cell surface in S505 with the degree of black spots and lithium plating on the cell surface in S512. If the degree of black spots and lithium plating on the cell surface in S512 is less severe than that in S505, maintain the positive terminal of the power supply connected to the second port of the test device and the negative terminal connected to the fourth port of the test device. Take a new cell, connect its positive terminal to the first port of the test device and its negative terminal to the third port of the test device, and continue to increase the charging current and / or discharging current of the cell. Perform a preset number of charge-discharge cycles on the new cell and observe the degree of black spots and lithium plating on the cell surface. Similarly, this process continues until the charging and discharging currents corresponding to the mildest degree of black spots and lithium plating on the cell surface are found after performing a preset number of charge-discharge cycles on the cell. These currents are then used as the charging and discharging currents for subsequent applications of the cell in electronic devices. This reduces the probability of black spots and lithium plating appearing on the cell surface as usage time increases after the cell is actually used in the electronic device. If the degree of black spots and lithium plating on the cell surface in S512 is more severe than that in S505, then the charging and discharging current in S505 is determined as the charging and discharging current for subsequent applications of the cell in electronic devices. This further reduces the probability of black spots and lithium plating appearing on the cell surface as usage time increases after the cell is actually used in the electronic device.

[0161] It should be noted that in the above embodiments, the increase or decrease of the charging current is merely an example. In actual use, it can be set according to the actual situation. This application does not limit it. Similarly, the increase or decrease of the discharge current is also merely an example. In actual use, it can be set according to the actual situation. This application does not limit it.

[0162] Based on any of the above embodiments, in one embodiment of this application, when evaluating the probability and degree of black spot phenomenon and lithium plating phenomenon when the battery cell is applied to an electronic device and the usage time increases, using the testing device in a normal temperature environment (e.g., 25°C), the preset number of times is 800 times; when evaluating the probability and degree of black spot phenomenon and lithium plating phenomenon when the battery cell is applied to an electronic device and the usage time increases, using the testing device in a high temperature environment (e.g., 45°C), the preset number of times is 400 times; when evaluating the probability and degree of black spot phenomenon and lithium plating phenomenon when the battery cell is applied to an electronic device and the usage time increases, using the testing device in a low temperature environment (e.g., 12°C), the preset number of times is 300 times. However, this application does not limit this, and it depends on the specific situation.

[0163] It should be noted that since the performance of battery cells is higher in low-temperature or high-temperature environments than in normal-temperature environments, in an optional embodiment of this application, the testing device and testing method provided in this application are preferably evaluated in a normal-temperature environment to assess the probability and degree of black spot phenomenon and lithium plating phenomenon when the battery cell is used in electronic devices as the usage time increases. However, this application does not limit this and it depends on the specific circumstances.

[0164] In summary, the testing apparatus and method provided in this application can evaluate the probability and degree of black spot phenomenon and lithium plating phenomenon when the battery cell is applied to electronic devices as the usage time increases, providing a reference for reducing the probability of black spot phenomenon and lithium plating phenomenon when the battery cell is applied to electronic devices as the usage time increases.

[0165] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0166] In the several embodiments provided in this example, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0167] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0168] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0169] Through the above description of the embodiments, those skilled in the art will clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0170] In the several embodiments provided in this example, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0171] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0172] Furthermore, in each embodiment of this invention, the functional units can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0173] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments. The aforementioned storage medium includes various media capable of storing program code, such as flash memory, portable hard disk, read-only memory, random access memory, magnetic disk, or optical disk.

[0174] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A testing device, characterized in that, include: Base plate: A first branch fixed on the base plate includes a first resistor element and a second resistor element connected in series. The end of the first resistor element away from the second resistor element is electrically connected to a first port of the test device, and the end of the second resistor element away from the first resistor element is electrically connected to a second port of the test device. The common terminal of the first resistor element and the second resistor element is a first node. A second branch is fixed on the base plate. The second branch includes a third resistor element and a fourth resistor element connected in series. The end of the third resistor element away from the fourth resistor element is electrically connected to the third port of the test device. The end of the fourth resistor element away from the third resistor element is electrically connected to the fourth port of the test device. The common terminal of the third resistor element and the fourth resistor element is the second node. A fifth resistive element is fixed on the base plate, with one end of the fifth resistive element electrically connected to the first node and the other end electrically connected to the second node; The first and third ports of the testing device are used for electrical connection with the battery cells, the second and fourth ports of the testing device are used for electrical connection with the power supply, and the second, fourth and fifth resistive elements are adjustable resistive elements.

2. The testing apparatus according to claim 1, characterized in that, The impedance of the second resistor element ranges from 0mΩ to 300mΩ, with an accuracy of 0.01mΩ; the impedance of the fourth resistor element ranges from 0mΩ to 300mΩ, with an accuracy of 0.01mΩ; and the impedance of the fifth resistor element ranges from 0mΩ to 300mΩ, with an accuracy of 0.01mΩ.

3. The testing apparatus according to claim 1, characterized in that, The first and third resistive elements are adjustable resistive elements, and the testing device further includes: A control switch is fixed on the base plate and located between the first resistive element and the first node. One end of the control switch is electrically connected to the end of the first resistive element near the second resistive element, and the other end is electrically connected to the first node. The open end of the first resistive element and the control switch is the third node. The third node is electrically connected to the fifth port of the test device, and the second node is also electrically connected to the sixth port of the test device. The fifth port and the sixth port are used for electrical connection to the power supply.

4. The testing apparatus according to claim 3, characterized in that, The control switch is a single-pole single-throw switch.

5. The testing apparatus according to claim 3, characterized in that, The impedance of the first resistive element ranges from 0mΩ to 300mΩ, with an accuracy of 0.01mΩ; the impedance of the third resistive element ranges from 0mΩ to 300mΩ, with an accuracy of 0.01mΩ.

6. A testing method, characterized in that, Applied to the testing apparatus according to any one of claims 1-5, the method comprises: Connect the positive terminal of the battery cell to the first port of the testing device, connect the negative terminal of the battery cell to the third port of the testing device, connect the positive terminal of the power supply to the second port of the testing device, and connect the negative terminal of the power supply to the fourth port of the testing device. Adjust the impedance value of at least one of the second, fourth, and fifth resistive elements. Under different combinations of impedance values, perform a preset number of charge-discharge cycles on different cells using a power supply, and then observe the degree of black spots and lithium plating on the surface of each cell.

7. The test method according to claim 6, characterized in that, The method also includes: Based on different impedance combinations, the degree of black spots and lithium plating on the surface of each battery cell was determined after performing a preset number of charge-discharge cycles on different battery cells using a power supply. The impedance combination with the least degree of black spots and lithium plating on the surface of the battery cell after performing a preset number of charge-discharge cycles was then selected.

8. The test method according to claim 6, characterized in that, The first resistive element and the third resistive element are adjustable resistive elements. The testing device further includes: a control switch fixed on the base plate and located between the first resistive element and the first node. One end of the control switch is electrically connected to the end of the first resistive element near the second resistive element, and the other end is electrically connected to the first node. The open end of the first resistive element and the control switch is the third node. The method also includes: Turn on the control switch to put it in the off state; Connect the positive terminal of the battery cell to the first port of the testing device, connect the negative terminal of the battery cell to the third port of the testing device, connect the positive terminal of the power supply to the fifth port of the testing device, and connect the negative terminal of the power supply to the sixth port of the testing device. Adjust the impedance values ​​of the first and third resistors. Under different impedance value combinations, perform a preset number of charge-discharge cycles on different cells using a power supply, and then observe the degree of black spots and lithium plating on the surface of each cell.

9. The test method according to claim 8, characterized in that, The method also includes: Based on different impedance value combinations, after performing a preset number of charge-discharge cycles on different battery cells using a power supply, the degree of black spots and lithium plating on the surface of each battery cell is determined. The impedance value combination with the least degree of black spots and lithium plating on the surface of the battery cell after performing a preset number of charge-discharge cycles is selected as the first impedance value combination.

10. The test method according to claim 9, characterized in that, When the control switch is closed, the method further includes: Based on the first impedance value combination, the impedance values ​​of the first resistive element and the third resistive element are set.

11. The test method according to claim 6, characterized in that, The testing method also includes: Connect the positive terminal of the battery cell to the first port of the test device, connect the negative terminal of the battery cell to the third port of the test device, connect the positive terminal of the power supply to the second port of the test device, and connect the negative terminal of the power supply to the fourth port of the test device. The impedance values ​​of the first resistive element, the second resistive element, the third resistive element, the fourth resistive element, and the fifth resistive element are fixed. By using different charging and discharging currents and performing a preset number of charge and discharge cycles on different cells using a power supply, the degree of black spots and lithium plating on the surface of each cell was observed.

12. The test method according to claim 11, characterized in that, The method also includes: Based on the degree of black spots and lithium plating on the surface of each cell, the charge / discharge current that produces the least degree of black spots and lithium plating on the cell surface after performing a preset number of charge / discharge cycles is selected.

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