A battery impedance test tool set and test method

Abstract

The application relates to a battery impedance test tool set and a test method. The battery impedance test tool set comprises a first tool and a second tool. The first tool comprises a first upper shell, a first lower shell, a positive electrode current collecting structure and a negative electrode current collecting structure. The first upper shell and the first lower shell are combined to form a closed first mounting cavity. The positive electrode current collecting structure and the negative electrode current collecting structure are arranged to extend outward from the first mounting cavity. The second tool comprises a second upper shell, a second lower shell, two positive electrode current conducting structures and two negative electrode current conducting structures. The second upper shell and the second lower shell are combined to form a closed second mounting cavity. Each positive electrode current conducting structure and each negative electrode current conducting structure is arranged to extend outward from the second mounting cavity. When the battery impedance is tested by the application, the required test sample is greatly reduced, the material cost can be effectively reduced, the test amount can be reduced, the test period can be shortened, the test consistency is good, and the test result is more reliable.

Description

Technical Field

[0001] This invention relates to the field of battery testing technology, and specifically to a battery impedance testing fixture and testing method. Background Technology

[0002] Currently, the impedance of lithium-ion batteries is often tested and studied by fabricating symmetrical cells. The existing testing process is as follows: the finished battery is charged and discharged to adjust the cell to a certain SOC (State of Charge); the battery is disassembled in a glove box, and the positive and negative electrode sheets obtained from the disassembly are reassembled to create a positive electrode symmetrical cell and a negative electrode symmetrical cell at a certain SOC; then, the impedance of the positive and negative electrodes of the cell at that SOC is measured by an electrochemical workstation.

[0003] However, when performing impedance testing across the entire SOC range (0-100%) using the above method, multiple batteries are required. The cells of these batteries need to be adjusted to different SOCs before symmetrical battery fabrication and impedance testing are performed at the corresponding SOCs. This results in a large number of samples, high material costs, a large testing volume, and a long testing cycle. Furthermore, using multiple cells inevitably raises consistency issues, leading to reduced reliability of the test results. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art in which the economic and time costs of battery impedance testing through symmetrical batteries are high and the reliability of the test results is low, thereby providing a battery impedance testing fixture and testing method.

[0005] To address the above problems, the present invention provides a battery impedance testing fixture, comprising:

[0006] The first tooling includes a first upper shell, a first lower shell, a positive current collector structure and a negative current collector structure. The first upper shell and the first lower shell are fastened together to form a sealed first mounting cavity. The positive current collector structure and the negative current collector structure both extend outward from the first mounting cavity.

[0007] The second tooling includes a second upper shell, a second lower shell, two positive electrode guiding structures and two negative electrode guiding structures. The second upper shell and the second lower shell are interlocked to form a sealed second mounting cavity. Each positive electrode guiding structure and each negative electrode guiding structure extends outward from the second mounting cavity.

[0008] Optionally, a first positioning groove is provided on the inner side of the first lower housing, and a second positioning groove is provided on the inner side of the second lower housing. The shape and size of the first positioning groove and the second positioning groove are adapted to the battery cell.

[0009] Optionally, the positive current collector structure is located on the first side outside the first positioning groove, and the negative current collector structure is located on the second side outside the first positioning groove, with the first side and the second side outside the first positioning groove facing each other; both positive current guide structures are located on the first side outside the second positioning groove, and both negative current guide structures are located on the second side outside the second positioning groove, with the first side and the second side outside the second positioning groove facing each other.

[0010] Optionally, the positive current collector structure includes: a positive current collector plate and a first positive current connector, both located in the first mounting cavity and disposed opposite to each other; and a first positive current post, extending out of the first mounting cavity and connected to at least one of the positive current collector plate and the first positive current connector.

[0011] The negative current collector structure includes: a negative current collector plate and a first negative current crimping member, both located in the first mounting cavity and disposed opposite to each other; and a first negative current post, extending out of the first mounting cavity and connected to at least one of the negative current collector plate and the first negative current crimping member.

[0012] Optionally, two positive electrode guiding structures are arranged at intervals, each positive electrode guiding structure including: a positive electrode guiding plate and a second positive electrode crimping member, both located in the second mounting cavity and arranged opposite to each other; a second positive electrode post, extending out of the second mounting cavity and connected to at least one of the positive electrode guiding plate and the second positive electrode crimping member;

[0013] Two negative electrode guiding structures are arranged at intervals. Each negative electrode guiding structure includes: a negative electrode guiding plate and a second negative electrode crimping member, both located in the second mounting cavity and arranged opposite to each other; and a second negative electrode post, extending out of the second mounting cavity and connected to at least one of the negative electrode guiding plate and the second negative electrode crimping member.

[0014] Optionally, the first tooling further includes a first sealing ring, which is located between the first upper housing and the first lower housing and is disposed along the outer periphery of the first mounting cavity; the second tooling further includes a second sealing ring, which is located between the second upper housing and the second lower housing and is disposed along the outer periphery of the second mounting cavity.

[0015] This invention also provides a battery impedance testing method, which uses the battery impedance testing fixture set described above to perform battery impedance testing. The method includes the following steps:

[0016] S10, stacking positive and negative electrode sheets to form a cell, placing the cell in the first tooling, and adding electrolyte into the first mounting cavity to form a battery;

[0017] S20: Adjust the battery's SOC to the preset value and perform a full-cell impedance test;

[0018] S30, disassemble the battery and take two electrodes with the same polarity to re-stack them, place the stacked structure in the second tooling, and add electrolyte into the second mounting cavity to form a symmetrical battery;

[0019] S40, for impedance testing of symmetrical cells;

[0020] S50, disassemble the symmetrical battery and repeat the above steps until the impedance test is completed under all preset values.

[0021] Optionally, step S10 includes:

[0022] A first negative electrode is placed between two first positive electrode plates, and a first separator is placed between the first positive electrode plate and the first negative electrode plate to form a first cell. The first cell is placed in a first tooling and electrolyte is added to form a first battery.

[0023] A second positive electrode is placed between two second negative electrode plates, and a second separator is placed between the second positive electrode plate and the second negative electrode plate to form a second cell. The second cell is placed in another first tooling and electrolyte is added to form a second battery.

[0024] Optionally, step S30 includes:

[0025] The first battery is disassembled, and the two first positive electrode plates are stacked. The stacked structure is placed in a second tooling and electrolyte is added to form a positive symmetrical battery.

[0026] The second battery is disassembled, and the two second negative electrode plates are stacked. The stacked structure is placed in another second tooling and electrolyte is added to form a negative electrode symmetrical battery.

[0027] Optionally, step S20 includes:

[0028] S21, Activate and capacitate the battery after initial assembly;

[0029] S22, adjust the SOC of the battery to a preset value based on the battery's capacity setting result;

[0030] S23, perform impedance testing on the battery.

[0031] The present invention has the following advantages:

[0032] The positive and negative electrode sheets are stacked to form a battery cell. The battery cell is placed in a first fixture, with all positive electrode tabs connected to the positive current collector and all negative electrode tabs connected to the negative current collector. Electrolyte is then added to the first mounting cavity to form a battery. After obtaining the battery, the SOC of the battery is adjusted to a preset value, and a full-cell impedance test can be performed. Then, the battery is disassembled, and two electrodes of the same polarity are re-stacked to form a stacked structure. The stacked structure is placed in a second fixture, and electrolyte is added to the second mounting cavity to obtain a positive-symmetrical battery or a negative-symmetrical battery. Then, impedance tests can be performed on the positive-symmetrical battery and the negative-symmetrical battery respectively. By disassembling the symmetrical battery and repeating the above steps, impedance tests at other SOCs can be completed.

[0033] Overall, by using the battery impedance testing fixture provided by this invention, the State of Charge (SOC) of the same cell can be continuously adjusted, and then the battery impedance test can be performed at the corresponding SOC, thereby completing the impedance test across the entire SOC range. As a result, the number of samples required for the overall test is greatly reduced, which can effectively reduce material costs, reduce the amount of testing, shorten the testing cycle, and ensure good test consistency and more reliable test results. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific 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 from these drawings without creative effort.

[0035] Figure 1 This is a top-view three-dimensional structural diagram of the first fixture in the battery impedance testing fixture assembly provided in an embodiment of the present invention;

[0036] Figure 2 This is a bottom-view perspective view of the first fixture in the battery impedance testing fixture assembly provided in an embodiment of the present invention.

[0037] Figure 3 This is a top-view perspective view of the second fixture in the battery impedance testing fixture assembly provided in an embodiment of the present invention.

[0038] Figure 4 This is a bottom-view perspective view of the second fixture in the battery impedance testing fixture assembly provided in an embodiment of the present invention.

[0039] Figure 5 A flowchart of the battery impedance testing method provided in an embodiment of the present invention is shown;

[0040] Figure 6This diagram illustrates the stacking of the first battery cell provided in an embodiment of the present invention. Figure 1 ;

[0041] Figure 7 This diagram illustrates the stacking of the first battery cell provided in an embodiment of the present invention. Figure 2 ;

[0042] Figure 8 This diagram illustrates the stacking of the second battery cell provided in an embodiment of the present invention. Figure 1 ;

[0043] Figure 9 This diagram illustrates the stacking of the second battery cell provided in an embodiment of the present invention. Figure 2 ;

[0044] Figure 10 This diagram illustrates a stacked positive electrode symmetrical battery provided in an embodiment of the present invention. Figure 1 ;

[0045] Figure 11 This diagram illustrates a stacked positive electrode symmetrical battery provided in an embodiment of the present invention. Figure 2 ;

[0046] Figure 12 This diagram illustrates the stacking of a negative electrode symmetrical battery according to an embodiment of the present invention. Figure 1 ;

[0047] Figure 13 This diagram illustrates the stacking of a negative electrode symmetrical battery according to an embodiment of the present invention. Figure 2 .

[0048] Explanation of reference numerals in the attached figures:

[0049] 10. First tooling; 11. First upper housing; 12. First lower housing; 121. First positioning groove; 13. Positive current collector structure; 131. Positive current collector plate; 132. First positive current collector crimping piece; 133. First positive current collector post; 14. Negative current collector structure; 141. Negative current collector plate; 142. First negative current collector crimping piece; 143. First negative current collector post; 15. First sealing ring; 16. First ear plate; 161. First connecting hole;

[0050] 20. Second tooling; 21. Second upper housing; 22. Second lower housing; 221. Second positioning groove; 23. Positive electrode flow guiding structure; 231. Positive electrode flow guiding plate; 232. Second positive electrode crimping component; 233. Second positive electrode post; 24. Negative electrode flow guiding structure; 241. Negative electrode flow guiding plate; 242. Second negative electrode crimping component; 243. Second negative electrode post; 25. Second sealing ring; 26. Second ear plate; 261. Second connecting hole;

[0051] 100, First positive electrode plate; 101, First positive electrode tab; 200, First negative electrode plate; 201, First negative electrode tab; 300, First diaphragm; 400, Second positive electrode plate; 401, Second positive electrode tab; 500, Second negative electrode plate; 501, Second negative electrode tab; 600, Second diaphragm. Detailed Implementation

[0052] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0056] Example 1

[0057] This embodiment provides a battery impedance testing fixture set, which includes a first fixture 10 and a second fixture 20.

[0058] like Figure 1 and Figure 2As shown, the first fixture 10 includes a first upper housing 11, a first lower housing 12, a positive current collector structure 13, and a negative current collector structure 14. The first upper housing 11 and the first lower housing 12 are interlocked to form a sealed first mounting cavity, and both the positive current collector structure 13 and the negative current collector structure 14 extend outward from the first mounting cavity.

[0059] like Figure 3 and Figure 4 As shown, the second tooling 20 includes a second upper housing 21, a second lower housing 22, two positive electrode guiding structures 23, and two negative electrode guiding structures 24. The second upper housing 21 and the second lower housing 22 are interlocked to form a sealed second mounting cavity, and each positive electrode guiding structure 23 and each negative electrode guiding structure 24 are extended outward from the second mounting cavity.

[0060] This battery impedance testing fixture can be used for battery impedance testing and research. The specific process is as follows:

[0061] (1) Stack the positive electrode and the negative electrode to form a battery cell. Place the battery cell in the first tooling 10 so that all the positive electrode tabs in the battery cell are connected to the positive current collector 13 and all the negative electrode tabs in the battery cell are connected to the negative current collector 14. Then, add electrolyte into the first mounting cavity to form a battery.

[0062] In this embodiment, two types of batteries are used to study the positive and negative electrode symmetrical battery. The first type of battery includes two positive electrode plates and one negative electrode plate disposed between the two positive electrode plates; the second type of battery includes two negative electrode plates and one positive electrode plate disposed between the two negative electrode plates.

[0063] (2) After obtaining the battery, adjust the SOC of the battery to the preset value and perform a full battery impedance test.

[0064] As you can understand, SOC represents the ratio of a battery's remaining capacity to its capacity when fully charged, usually expressed as a percentage. A SOC of 0 indicates the battery is fully discharged, while a SOC of 100% indicates the battery is fully charged.

[0065] In this embodiment, the preset values ​​for SOC include: 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%. Before the first full-cell impedance test, the preset value of SOC is adjusted to 5%.

[0066] (3) After completing the full cell impedance test, disassemble the battery and take two electrodes with the same polarity to re-stack to form a stacked structure. Place the stacked structure in the second tooling 20.

[0067] Specifically, for the first type of battery, two positive electrode plates are re-stacked, the stacked structure is placed in a second tooling 20, and the tabs of the two positive electrode plates are connected to the two positive current-conducting structures 23 in a one-to-one correspondence; then, electrolyte is added into the second mounting cavity to form a positive symmetrical battery.

[0068] For the second type of battery, take two negative electrode plates and stack them again. Place the stacked structure in another second tooling 20 and connect the tabs of the two negative electrode plates to the two negative electrode current-conducting structures 24 one by one. Then, add electrolyte into the second mounting cavity to form a negative electrode symmetrical battery.

[0069] (4) Impedance tests were performed on the positive electrode symmetrical battery and the negative electrode symmetrical battery respectively.

[0070] In this embodiment, impedance testing is performed using an electrochemical workstation.

[0071] (5) Disassemble the symmetrical battery and repeat the above steps to adjust the SOC to another preset value and perform impedance testing until the impedance test under all preset values ​​is completed.

[0072] Overall, by using the aforementioned battery impedance testing fixture, the same battery cell can be adjusted to different states of charge (SOC) before undergoing impedance testing at the corresponding SOC. This eliminates the need to disassemble multiple batteries, significantly reducing the number of samples required for testing, saving material costs, reducing the amount of testing, and shortening the testing cycle. Furthermore, the good consistency of the tests improves the reliability of the results.

[0073] Next, the structure of the first tooling 10 will be further described.

[0074] like Figure 1 and Figure 2 As shown, the first upper shell 11 is a rectangular box-shaped structure with an open bottom, and the first lower shell 12 is a rectangular plate-shaped structure. Preferably, both the first upper shell 11 and the first lower shell 12 are made of PVDF (polyvinylidene difluoride).

[0075] See again Figure 1 A first positioning groove 121 is provided on the inner side of the first lower housing 12. The shape and size of the first positioning groove 121 are adapted to the battery cell. After the positive electrode and negative electrode are stacked to form the battery cell, the battery cell is placed in the first positioning groove 121 to achieve accurate positioning of the battery cell.

[0076] In this embodiment, the positive current collector 13 is located on the first side outside the first positioning groove 121, and the negative current collector 14 is located on the second side outside the first positioning groove 121, with the first and second sides outside the first positioning groove 121 facing each other. During stacking, refer to... Figure 6and Figure 7 , or refer to Figure 10 and Figure 11 The positive electrode tab (referred to as the positive electrode tab) and the negative electrode tab (referred to as the negative electrode tab) in the battery cell are respectively set on opposite sides of the battery cell. Then the battery cell is placed in the first positioning groove 121, so that the positive electrode tab is connected to the positive current collector 13 and the negative electrode tab is connected to the negative current collector 14, thereby enabling current conduction.

[0077] For the positive current collector structure 13, such as Figure 1 and Figure 2 As shown, it includes a positive current collector 131, a first positive electrode crimping member 132, and a first positive electrode post 133. The positive current collector 131 and the first positive electrode crimping member 132 are both located within a first mounting cavity and are arranged opposite to each other. The first positive electrode post 133 extends outward from the first mounting cavity and is connected to at least one of the positive current collector 131 and the first positive electrode crimping member 132. In this embodiment, the positive current collector 131 is fixed to the first lower housing 12, and a first positive electrode post 133 is connected to the lower side of the positive current collector 131. The first positive electrode crimping member 132 is fixed to the first upper housing 11 and located above the positive current collector 131, and a first positive electrode post 133 is connected to the upper side of the first positive electrode crimping member 132.

[0078] The negative current collector structure 14 includes a negative current collector plate 141, a first negative current crimping member 142, and a first negative current post 143. The negative current collector plate 141 and the first negative current crimping member 142 are both located within a first mounting cavity and are arranged opposite to each other. The first negative current post 143 extends outward from the first mounting cavity and is connected to at least one of the negative current collector plate 141 and the first negative current crimping member 142. In this embodiment, the negative current collector plate 141 is fixed to the first lower housing 12, and a first negative current post 143 is connected to the lower side of the negative current collector plate 141. The first negative current crimping member 142 is fixed to the first upper housing 11 and located above the negative current collector plate 141, and a first negative current post 143 is connected to the upper side of the first negative current crimping member 142.

[0079] With the above setup, after the battery cell is placed in the first mounting cavity, the positive electrode tab can be clamped and fixed by the positive current collector 131 and the first positive electrode crimping member 132, and the negative electrode tab can be clamped and fixed by the negative current collector 141 and the first negative electrode crimping member 142. Furthermore, after adding electrolyte to form a battery, the battery can be connected to external experimental equipment for testing by connecting the positive and negative terminals.

[0080] Overall, by applying the above-mentioned positive current collector structure 13 and negative current collector structure 14, the operation can be simplified and the stable and reliable current conduction can be guaranteed.

[0081] In this embodiment, as Figure 2 As shown, the first positive electrode crimping member 132 is an integrated structure, which includes two spaced-apart first positive electrode crimping posts and a first positive electrode adapter piece. The two first positive electrode crimping posts correspond one-to-one with the two positive electrode tabs in the aforementioned first type of battery, and the first positive electrode adapter piece is disposed between the two first positive electrode crimping posts and the first upper housing 11.

[0082] The first negative electrode crimping member 142 is also an integrated structure, which includes two spaced-apart first negative electrode crimping posts and a first negative electrode adapter piece. The two first negative electrode crimping posts correspond one-to-one with the two negative electrode tabs in the aforementioned first type of battery, and the first negative electrode adapter piece is disposed between the two first negative electrode crimping posts and the first upper housing 11.

[0083] In terms of materials, the positive current collector 131, the first positive electrode crimping member 132 and the first positive electrode post 133 are all made of aluminum, while the negative current collector 141, the first negative electrode crimping member 142 and the first negative electrode post 143 are all made of copper.

[0084] like Figure 1 As shown, the first tooling 10 also includes a first sealing ring 15, which is located between the first upper housing 11 and the first lower housing 12 and is disposed along the outer periphery of the first mounting cavity. Accordingly, after the first upper housing 11 and the first lower housing 12 are engaged, the first sealing ring 15 can seal the first mounting cavity to prevent electrolyte leakage. In this embodiment, the first sealing ring 15 has a rectangular structure and is fixed to the first lower housing 12.

[0085] In other aspects, to facilitate the connection between the first upper housing 11 and the first lower housing 12, such as Figure 1 As shown, multiple first ear plates 16 are provided on the exterior of both the first upper housing 11 and the first lower housing 12, and the first ear plates 16 on the first upper housing 11 and the first ear plates 16 on the first lower housing 12 correspond one-to-one. Each first ear plate 16 is provided with a first connecting hole 161, through which bolts can be installed, thereby achieving relative fixation between the first upper housing 11 and the first lower housing 12.

[0086] Finally, the structure of the second tooling 20 will be further described.

[0087] like Figure 3 and Figure 4 As shown, the second upper shell 21 is a rectangular box-shaped structure with an open bottom, and the second lower shell 22 is a rectangular plate-shaped structure. Preferably, both the second upper shell 21 and the second lower shell 22 are made of PVDF material.

[0088] See again Figure 3A second positioning groove 221 is provided on the inner side of the second lower housing 22. The shape and size of the second positioning groove 221 are adapted to the battery cell. In this embodiment, after disassembling the battery and re-stacking the two electrodes with the same polarity, the shape and size of the resulting stacked structure are basically the same as the original battery cell. Therefore, by placing the stacked structure in the second positioning groove 221, accurate positioning of the stacked structure can be achieved.

[0089] In this embodiment, both positive electrode guiding structures 23 are located on the first side outside the second positioning groove 221, and both negative electrode guiding structures 24 are located on the second side outside the second positioning groove 221. The first side and the second side outside the second positioning groove 221 are opposite to each other.

[0090] When stacking two positive electrode plates, refer to Figure 8 and Figure 9 By placing the two positive electrode tabs on the same side of the laminated structure and then placing the laminated structure in the second positioning groove 221, the two positive electrode tabs can be connected one-to-one with the two positive current-conducting structures 23, thereby enabling current conduction. Similarly, when laminating two negative electrode plates, refer to... Figure 12 and Figure 13 By placing the two negative electrode tabs on the same side of the laminated structure and then placing the laminated structure in the second positioning groove 221, the two negative electrode tabs can be connected one-to-one with the two negative current-conducting structures 24, thereby enabling current conduction.

[0091] For specific structural settings, refer to Figure 3 and Figure 4 Two positive electrode guiding structures 23 are spaced apart. Each positive electrode guiding structure 23 includes a positive electrode guiding plate 231, a second positive electrode crimping member 232, and a second positive electrode post 233. The positive electrode guiding plate 231 and the second positive electrode crimping member 232 are both located within the second mounting cavity and are arranged opposite to each other. The second positive electrode post 233 extends outward from the second mounting cavity and is connected to at least one of the positive electrode guiding plate 231 and the second positive electrode crimping member 232. In this embodiment, the positive electrode guiding plate 231 is fixed to the second lower housing 22, and a second positive electrode post 233 is connected to the lower side of the positive electrode guiding plate 231. The second positive electrode crimping member 232 is fixed to the second upper housing 21 and located above the positive electrode guiding plate 231, and a second positive electrode post 233 is connected to the upper side of the second positive electrode crimping member 232.

[0092] Two negative electrode guiding structures 24 are spaced apart. Each negative electrode guiding structure 24 includes a negative electrode guiding plate 241, a second negative electrode crimping member 242, and a second negative electrode post 243. The negative electrode guiding plate 241 and the second negative electrode crimping member 242 are both located within the second mounting cavity and are arranged opposite to each other. The second negative electrode post 243 extends from the second mounting cavity and is connected to at least one of the negative electrode guiding plate 241 and the second negative electrode crimping member 242. In this embodiment, the negative electrode guiding plate 241 is fixed to the second lower housing 22, and a second negative electrode post 243 is connected to the lower side of the negative electrode guiding plate 241. The second negative electrode crimping member 242 is fixed to the second upper housing 21 and located above the negative electrode guiding plate 241, and a second negative electrode post 243 is connected to the upper side of the second negative electrode crimping member 242.

[0093] When two positive electrode plates are stacked, after the stacked structure is placed in the first mounting cavity, one positive electrode tab can be clamped and fixed by the positive electrode guide plate 231 and the second positive electrode crimping member 232 in one positive electrode current guiding structure 23, and the other positive electrode tab can be clamped and fixed by the positive electrode guide plate 231 and the second positive electrode crimping member 232 in the other positive electrode current guiding structure 23. Furthermore, after adding electrolyte to form a positive electrode symmetrical battery, the positive electrode symmetrical battery can be connected to external experimental equipment for testing via the positive electrode terminal connection. Similarly, after two negative electrode plates are stacked to form a negative electrode symmetrical battery, the negative electrode symmetrical battery can be connected to external experimental equipment for testing via the negative electrode current guiding structure 24.

[0094] Overall, by applying the above-mentioned positive electrode current-conducting structure 23 and negative electrode current-conducting structure 24, the operation can be simplified and the stable and reliable current conduction can be guaranteed.

[0095] In terms of materials, the positive electrode guide plate 231, the second positive electrode crimping member 232, and the second positive electrode post 233 are all made of aluminum, while the negative electrode guide plate 241, the second negative electrode crimping member 242, and the second negative electrode post 243 are all made of copper.

[0096] like Figure 3 As shown, the second tooling 20 also includes a second sealing ring 25, which is located between the second upper housing 21 and the second lower housing 22 and is disposed along the outer periphery of the second mounting cavity. Accordingly, after the second upper housing 21 and the second lower housing 22 are engaged, the second sealing ring 25 can seal the second mounting cavity to prevent electrolyte leakage. In this embodiment, the second sealing ring 25 has a rectangular structure and is fixed to the second lower housing 22.

[0097] In other aspects, to facilitate the connection between the second upper housing 21 and the second lower housing 22, such as Figure 3As shown, multiple second ear plates 26 are provided on the exterior of both the second upper housing 21 and the second lower housing 22, and the second ear plates 26 on the second upper housing 21 and the second ear plates 26 on the second lower housing 22 correspond one-to-one. Each second ear plate 26 is provided with a second connecting hole 261, through which bolts can be installed, thereby achieving relative fixation between the second upper housing 21 and the second lower housing 22.

[0098] Example 2

[0099] This embodiment provides a battery impedance testing method, which uses the battery impedance testing fixture set described in Embodiment 1 to perform impedance testing on the battery cell. The battery impedance testing method includes the following steps:

[0100] S10, stacking positive and negative electrode sheets to form a battery cell, placing the battery cell in the first tooling 10, and adding electrolyte into the first mounting cavity to form a battery.

[0101] Specifically, in step S10, two types of batteries are manufactured.

[0102] The first type of battery is manufactured as follows:

[0103] (1)Reference Figure 6 and Figure 7 A first negative electrode 200 is disposed between two first positive electrode plates 100, and a first separator 300 is disposed between the first positive electrode plate 100 and the first negative electrode plate 200, thereby forming a first battery cell by stacking the plates. In this embodiment, before stacking, the positive and negative electrode plates are first treated with adhesive on one side to facilitate stacking.

[0104] (2) Then, the first cell is placed in a first tooling 10 and electrolyte is added to the first tooling 10 to form the first battery.

[0105] In this embodiment, a first positive electrode tab 101 is also provided on the first positive electrode plate 100, and a first negative electrode tab 201 is provided on the first negative electrode plate 200. The two first positive electrode tabs 101 are located on the same side, and the first negative electrode tab 201 is located on the side opposite to the first positive electrode tab 101.

[0106] The second type of battery is made as follows:

[0107] (1)Reference Figure 8 and Figure 9A second positive electrode 400 is placed between two second negative electrode plates 500, and a second separator 600 is placed between the second positive electrode plate 400 and the second negative electrode plate 500 to form a second cell. Similar to the manufacturing of the aforementioned battery, before stacking, the positive and negative electrode plates are first treated with adhesive on one side to facilitate stacking.

[0108] (2) Then, the second cell is placed in another first tooling 10 and electrolyte is added to the first tooling 10 to form a second battery.

[0109] In this embodiment, a second positive electrode tab 401 is also provided on the second positive electrode plate 400, and a second negative electrode tab 501 is provided on the second negative electrode plate 500. The two second negative electrode tabs 501 are located on the same side, and the second positive electrode tab 401 is located on the side opposite to the second negative electrode tab 501.

[0110] S20 adjusts the battery's SOC to a preset value and performs a full-cell impedance test.

[0111] Specifically, step S20 includes:

[0112] S21, Activate and capacitate the battery after initial assembly;

[0113] S22, adjust the SOC of the battery to a preset value based on the battery's capacity setting result;

[0114] S23, perform impedance testing on the battery.

[0115] Taking the first battery as an example, its activation and capacity determination process is as follows: the first cell is activated once at a rate of 0.05C (also known as one cycle), then two cycles are performed at a rate of 0.1C, and three cycles are performed at a rate of 0.33C to calibrate the actual capacity C1 of the first cell.

[0116] Then, based on the calibrated capacity C1, the first battery is charged, the SOC of the first battery is adjusted to 5%, and then the full battery impedance test is performed.

[0117] S30: Disassemble the battery and take two electrodes with the same polarity to re-stack. Place the stacked structure in the second tooling 20 and add electrolyte into the second mounting cavity to form a symmetrical battery.

[0118] In this embodiment, the first battery and the second battery need to be disassembled separately. The disassembly operation can be carried out in a glove box or a drying room.

[0119] After disassembling the first battery, press Figure 10 As shown, two first positive electrode plates 100 are stacked to obtain the following result: Figure 11The stacked structure shown can be placed in a second tooling 20 and filled with electrolyte to obtain a positive electrode symmetrical battery.

[0120] After disassembling the second battery, press Figure 12 As shown, two second negative electrode plates 500 are stacked to obtain the following result. Figure 13 The stacked structure shown can be placed in another second tooling 20 and filled with electrolyte to obtain a negative electrode symmetrical battery.

[0121] S40 is used to perform impedance testing on symmetrical cells.

[0122] Understandably, impedance tests should be performed separately for the positive electrode symmetrical cell and the negative electrode symmetrical cell.

[0123] S50, disassemble the symmetrical battery and repeat the above steps until the impedance test is completed under all preset values.

[0124] In this embodiment, the disassembly of the positive electrode symmetrical battery and the negative electrode symmetrical battery is still carried out in the glove box or drying room.

[0125] Taking a positive electrode symmetrical battery as an example, after disassembly, then press... Figure 6 and Figure 7 As shown, two first positive electrode plates 100 are stacked with the original first negative electrode plate 200 and first separator 300 to obtain a first battery cell. The first battery cell is then placed in the first fixture 10 to obtain a first battery. It should be noted that since this first battery is obtained from the second assembly, it is not necessary to reactivate or capacitate it.

[0126] Afterwards, the first battery is charged for a certain period of time, and its SOC is adjusted to 10%. Then, the full battery impedance test and the positive electrode symmetrical battery impedance test can be performed at this SOC level.

[0127] After completing the battery impedance test at a SOC of 10%, repeat the above steps to achieve battery impedance tests at SOCs of 20%, 30%, and other conditions.

[0128] In this embodiment, the preset values ​​for SOC include: 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%. For every 5 percentage point increase in SOC, an additional 9 minutes of charging is required. For example, increasing SOC from 5% to 10% requires 9 minutes of charging; increasing SOC from 10% to 20% requires 18 minutes of charging.

[0129] As for the negative electrode symmetrical battery, its disassembly and retesting process is similar to that of the positive electrode symmetrical battery, and will not be described in detail here.

[0130] Overall, by using the battery impedance testing method described above, the same battery cell can be adjusted to different states of charge (SOC) before conducting impedance tests at the corresponding SOC. This eliminates the need to disassemble multiple batteries, significantly reducing the number of samples required for overall testing, thus saving material costs, reducing the amount of testing, and shortening the testing cycle. Furthermore, the good consistency of the tests improves the reliability of the results.

[0131] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A battery impedance testing fixture, characterized in that, include: The first tooling (10) includes a first upper shell (11), a first lower shell (12), a positive current collector (13), and a negative current collector (14). The first upper shell (11) and the first lower shell (12) are engaged to form a sealed first mounting cavity. The positive current collector (13) and the negative current collector (14) both extend outward from the first mounting cavity. The second tooling (20) includes a second upper shell (21), a second lower shell (22), two positive electrode guiding structures (23) and two negative electrode guiding structures (24). The second upper shell (21) and the second lower shell (22) are engaged to form a sealed second mounting cavity. Each of the positive electrode guiding structures (23) and each of the negative electrode guiding structures (24) extends outward from the second mounting cavity. The positive current collector structure (13) includes: a positive current collector plate (131) and a first positive current crimping member (132), both located in the first mounting cavity and arranged opposite to each other; a first positive current post (133) extends out of the first mounting cavity and is connected to at least one of the positive current collector plate (131) and the first positive current crimping member (132); The negative current collector structure (14) includes: a negative current collector plate (141) and a first negative current crimping member (142), both located in the first mounting cavity and arranged opposite to each other; a first negative current post (143) extending out of the first mounting cavity and connected to at least one of the negative current collector plate (141) and the first negative current crimping member (142).

2. The battery impedance testing fixture according to claim 1, characterized in that, The inner side of the first lower housing (12) is provided with a first positioning groove (121), and the inner side of the second lower housing (22) is provided with a second positioning groove (221). The shape and size of the first positioning groove (121) and the second positioning groove (221) are adapted to the battery cell.

3. The battery impedance testing fixture according to claim 2, characterized in that, The positive current collector structure (13) is located on the first side outside the first positioning groove (121), and the negative current collector structure (14) is located on the second side outside the first positioning groove (121). The first side and the second side outside the first positioning groove (121) are opposite to each other. Both positive electrode guiding structures (23) are located on the first side outside the second positioning groove (221), and both negative electrode guiding structures (24) are located on the second side outside the second positioning groove (221). The first side and the second side outside the second positioning groove (221) are opposite to each other.

4. The battery impedance testing fixture according to claim 1, characterized in that, Two positive electrode guiding structures (23) are arranged at intervals. Each positive electrode guiding structure (23) includes: a positive electrode guiding plate (231) and a second positive electrode crimping member (232), both located in the second mounting cavity and arranged opposite to each other; a second positive electrode post (233) extends out of the second mounting cavity and is connected to at least one of the positive electrode guiding plate (231) and the second positive electrode crimping member (232); Two negative electrode guiding structures (24) are arranged at intervals. Each negative electrode guiding structure (24) includes: a negative electrode guiding plate (241) and a second negative electrode crimping member (242), both located in the second mounting cavity and arranged opposite to each other; a second negative electrode post (243) extends out of the second mounting cavity and is connected to at least one of the negative electrode guiding plate (241) and the second negative electrode crimping member (242).

5. The battery impedance testing fixture according to any one of claims 1-4, characterized in that, The first tooling (10) further includes a first sealing ring (15), which is located between the first upper housing (11) and the first lower housing (12) and is disposed along the outer periphery of the first mounting cavity; The second tooling (20) also includes a second sealing ring (25), which is located between the second upper housing (21) and the second lower housing (22) and is disposed along the outer periphery of the second mounting cavity.

6. A method for testing battery impedance, characterized in that, The battery impedance test is performed using the battery impedance test fixture as described in any one of claims 1-5, comprising the following steps: S10, stack the positive electrode and the negative electrode to form a cell, place the cell in the first tooling (10), and add electrolyte into the first mounting cavity to form a battery; S20, adjust the SOC of the battery to a preset value and perform a full battery impedance test; S30, disassemble the battery and take two electrodes with the same polarity to re-stack, place the stacked structure in the second tooling (20), and add electrolyte into the second mounting cavity to form a symmetrical battery; S40, perform impedance testing on the symmetrical battery; S50, disassemble the symmetrical battery and repeat the above steps until the impedance test under all preset values ​​is completed.

7. The battery impedance testing method according to claim 6, characterized in that, Step S10 includes: A first negative electrode (200) is disposed between two first positive electrode plates (100), and a first separator (300) is disposed between the first positive electrode plate (100) and the first negative electrode plate (200) to form a first cell. The first cell is placed in a first tooling (10) and electrolyte is added to form a first battery. A second positive electrode (400) is disposed between two second negative electrode plates (500), and a second separator (600) is disposed between the second positive electrode plate (400) and the second negative electrode plate (500) to form a second cell. The second cell is placed in another first tooling (10) and electrolyte is added to form a second battery.

8. The battery impedance testing method according to claim 7, characterized in that, Step S30 includes: The first battery is disassembled, and the two first positive electrode plates (100) are stacked. The stacked structure is placed in a second tooling (20) and electrolyte is added to form a positive electrode symmetrical battery. The second battery is disassembled, and the two second negative electrode plates (500) are stacked. The stacked structure is placed in another second tooling (20) and electrolyte is added to form a negative electrode symmetrical battery.

9. The battery impedance testing method according to any one of claims 6-8, characterized in that, Step S20 includes: S21, the battery that has been initially assembled is activated and its capacity is adjusted; S22, Adjust the SOC of the battery to a preset value according to the battery's capacity determination result; S23, perform an impedance test on the battery.

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