Battery cell and battery pack

Abstract

The application relates to the technical field of lithium batteries, and provides a battery cell and a battery pack. The battery cell comprises a shell containing a pole group, a cover plate connected to the shell, and a lithium precipitation detection structure. The lithium precipitation detection structure comprises a reference column arranged on the cover plate and a reference pole electrically connected to the reference column through a conductive assembly. The conductive assembly is insulated from the pole group and the cover plate, and the reference pole is fixed to a position close to a negative electrode lug of a negative electrode sheet on the outermost layer of the pole group. The battery cell provided by the application not only does not damage the original sealing structure and internal structure of the battery cell, but also is beneficial to realizing real-time lithium precipitation detection while guaranteeing the basic performance of the battery cell. Moreover, the reference pole is arranged at the position close to the negative electrode lug of the negative electrode sheet on the outermost layer of the pole group, so that the lithium precipitation characteristic signal can be captured when the lithium precipitation is in an early stage, thereby the lithium precipitation hidden danger can be found earlier, the lithium precipitation detection sensitivity is improved, and early warning is realized.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, and in particular to a battery cell. This application also relates to a battery pack incorporating the aforementioned battery cell. Background Technology

[0002] As a core component of new energy vehicles and energy storage systems, lithium-ion power batteries are experiencing a continuous increase in demand for high energy density and fast charging. However, under low-temperature or high-rate charging conditions, lithium ions are prone to irreversibly depositing on the negative electrode surface, forming lithium dendrites (i.e., lithium plating). Thermal runaway is directly related to lithium plating in battery cells—lithium dendrites not only accelerate capacity decay but may also puncture the separator, causing internal short circuits and seriously threatening the safety of the battery system.

[0003] Current lithium plating detection methods mainly rely on electrochemical model back-calculation or material characterization after disassembly. However, the former suffers from high accuracy due to interference from operating conditions, while the latter requires damaging the cell structure and cannot be monitored in real time. The response delay of traditional lithium plating detection methods leads to a significant lag in lithium plating early warning. Utility Model Content

[0004] In view of this, this application aims to propose a battery cell that facilitates real-time lithium plating detection and enables early warning.

[0005] To achieve the above objectives, the technical solution of this application is implemented as follows: A battery cell includes a housing containing an electrode assembly, a cover plate connected to the housing, and a lithium plating detection structure; The lithium plating detection structure includes a reference post disposed on the cover plate and a reference electrode electrically connected to the reference post through a conductive component. The conductive component is insulated from the electrode group and from the cover plate. The reference electrode is fixed to the outermost negative electrode sheet of the electrode group near the negative electrode tab.

[0006] Furthermore, the reference post is located between the positive and negative posts on the cover plate and is positioned close to the negative post, and the material of the reference post is the same as that of the negative post; and / or, the reference post is riveted to the cover plate and is insulated from the cover plate.

[0007] Furthermore, the conductive component includes a conductive element and an electronic insulating layer covering the outer peripheral surface of the conductive element, wherein the conductive element is made of one of copper, aluminum, and silver.

[0008] Furthermore, the reference electrode is columnar and has a first metal base, a first active material layer, and a first electronic insulating layer arranged sequentially from the inside to the outside; the first metal base is electrically connected to the conductive component, the first active material layer covers the outer surface of the first metal base, and the first electronic insulating layer covers the outer surface of the first active material layer.

[0009] Furthermore, the diameter D of the first metal substrate is between 10 μm and 50 μm; and / or, the axial dimension L of the first active material layer on the first metal substrate is between 0.5 cm and 1.0 cm.

[0010] Furthermore, the reference electrode is sheet-shaped and has a second metal base, a second active material layer, and a second electronic insulating layer; the second metal base is electrically connected to the conductive component, the second active material layer covers the outer peripheral surface of the second metal base, and the second electronic insulating layer covers the outer surface of the second active material layer.

[0011] Furthermore, the thickness of the second metal substrate is between 5 μm and 30 μm.

[0012] Furthermore, the reference electrode includes a mesh metal base, a third active material layer, and a third electronic insulating layer; the mesh metal base is electrically connected to the conductive component, the third active material layer covers the outer peripheral surface of the mesh metal base, and the third electronic insulating layer covers the outer peripheral surface of the third active material layer.

[0013] Furthermore, the thickness of the mesh metal substrate is between 10μm and 30μm, and the mesh size of the mesh metal substrate is between 50 mesh and 200 mesh.

[0014] Compared with related technologies, this application has the following advantages: (1) The battery cell described in this application, through the lithium plating detection structure, has a reference post in the lithium plating detection structure placed on the cover plate, and a reference electrode placed near the negative electrode tab of the outermost negative electrode sheet of the electrode group, and the reference post and the reference electrode are electrically connected through a conductive component. In this way, on the one hand, the reference post is integrated into the cover plate without damaging the original sealing structure and internal structure of the battery cell, and while ensuring the basic performance of the battery cell, it is conducive to realizing real-time lithium plating detection. On the other hand, the conductive component is insulated from the electrode group and the cover plate, which can avoid the reference electrode from being electrically connected to other conductive components inside the battery cell (such as the positive electrode and the shell) to form a short circuit.

[0015] Meanwhile, since the outermost negative electrode sheet of the electrode assembly is located near the negative electrode tab, where electrons accumulate significantly during the cell charging process, it is the weakest point for lithium plating. Setting the reference electrode at this location allows for the capture of lithium plating characteristic signals in the early stages of lithium plating, thereby enabling earlier detection of potential lithium plating problems. This improves the sensitivity of lithium plating detection and facilitates early warning.

[0016] (2) Setting the reference post close to the negative electrode post can shorten the electrical path between the conductive component and the negative electrode tab, which helps to ensure the stability of the detection signal; setting the reference post and the cover plate to be riveted and fixed together helps to ensure the reliability of the connection between the reference post and the cover plate. At the same time, the insulation between the reference post and the cover plate can prevent the reference post and the cover plate from forming a conductive path.

[0017] (3) The conductive component includes a conductive element and an electronic insulating layer covering the outer periphery of the conductive element. The conductive element is made of one of copper, aluminum and silver, which not only provides good insulation between the conductive component and the electrode group to avoid short circuits, but also gives the conductive element excellent conductivity.

[0018] (4) The reference electrode adopts a columnar structure, so that the bottom of the first metal base is electrically connected to the conductive component for conducting the detection circuit. The first active material layer can reflect the lithium ion concentration and potential change near the negative electrode tab. The first electronic insulating layer can prevent the reference electrode from directly conducting with the negative electrode sheet and prevent electrons from passing through the negative electrode tab.

[0019] (5) Limiting the diameter of the first metal substrate can not only prevent it from being too thin and easy to break and difficult to process, but also prevent the electrode assembly from being damaged due to being too thick. Limiting the axial dimension of the first active material layer in the first metal substrate can not only ensure that the reference electrode has sufficient active area, but also avoid the large volume affecting the use of the electrode assembly.

[0020] (6) The reference electrode adopts a sheet structure, which makes the bottom of the second metal base electrically connected to the conductive component for conducting the detection circuit. The second active material layer can reflect the lithium ion concentration and potential changes near the negative electrode tab. The second electronic insulating layer can also prevent the reference electrode from directly conducting with the negative electrode sheet and prevent electrons from passing through the negative electrode tab. Moreover, the sheet structure is conducive to increasing the contact area, better capturing lithium plating characteristic signals, and improving the lithium plating detection sensitivity.

[0021] (7) Limiting the thickness of the second metal substrate can prevent the electrode from being difficult to form due to insufficient thickness or damaging the electrode due to excessive thickness when implanted into the electrode assembly.

[0022] (8) The reference electrode adopts a mesh metal base, a third active material layer and a third electronic insulating layer, so that the mesh metal base is electrically connected to the conductive component for conducting the detection circuit. The third active material layer can reflect the lithium ion concentration and potential change near the negative electrode tab. The third electronic insulating layer can also prevent the reference electrode from directly conducting with the negative electrode sheet and prevent electrons from passing through the negative electrode tab.

[0023] (9) Limiting the thickness of the mesh metal substrate and the mesh size allows for the loading of more active materials, improving service life and ensuring the structural strength of the reference electrode. Furthermore, limiting the porosity allows for a balance between the amount of active material used and the volume occupied.

[0024] This application also proposes a battery pack in which the battery cells described above are provided.

[0025] The battery pack described in this application, by using the aforementioned cells, can achieve real-time lithium plating detection without damaging the original sealing structure and internal structure of the cells, ensuring the basic performance of the cells. Furthermore, it can capture lithium plating characteristic signals when lithium plating is in its early stages, thereby enabling earlier detection of potential lithium plating hazards, facilitating early warning, and ultimately improving the safety of the battery system. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the battery cell structure described in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the cover plate and the lithium plating detection structure in the embodiment of this application. Figure 3 This is a schematic diagram of the electrode assembly and lithium plating detection structure in cooperation with each other, as described in the embodiments of this application. Figure 4 This is a schematic diagram of the first structure of the lithium plating detection structure described in the embodiments of this application; Figure 5 This is a schematic diagram of the second structure of the lithium plating detection structure described in the embodiments of this application; Figure 6 This is a schematic diagram of the third structure of the lithium plating detection structure described in the embodiments of this application; Figure 7 This is a schematic diagram of the structure of the bottom of the mesh metal substrate described in the embodiments of this application; Explanation of reference numerals in the attached figures: 2. Cover plate; 3. Electrode assembly; 4. Lithium plating detection structure; 201, Positive terminal; 202, Negative terminal; 203, Injection port; 204, Explosion-proof valve; 301, Positive tab; 302, Negative tab; 401, Reference terminal; 402, Conductive component; 403, Reference electrode; 4021, Conductive component; 4022, Electronic insulating layer; 4031, First metal substrate base; 4032, First active material layer; 4033, First electronic insulating layer; 4034, Second metal substrate base; 4035, Second active material layer; 4036, Second electronic insulating layer; 4037, Mesh metal substrate base; 4038, Third electronic insulating layer. Detailed Implementation

[0027] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0029] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0031] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0033] An embodiment of the first aspect of this application provides a battery cell that facilitates real-time lithium plating detection and enables early warning.

[0034] In related technologies, under low-temperature or high-rate charging scenarios, lithium ions are prone to irreversibly depositing on the surface of the negative electrode to form lithium dendrites (i.e., lithium plating). Thermal runaway is directly related to lithium plating in the battery cell—lithium dendrites not only accelerate capacity decay but may also puncture the separator, causing internal short circuits and seriously threatening the safety of the battery system.

[0035] Current lithium plating detection methods mainly rely on electrochemical model back-calculation or material characterization after disassembly. However, the former suffers from high accuracy due to interference from operating conditions, while the latter requires damaging the cell structure and cannot be monitored in real time. The response delay of traditional lithium plating detection methods leads to a significant lag in lithium plating early warning.

[0036] In the existing square cell structure, only the positive and negative terminals are set on the cell cover. During the operation of the cell, it is impossible to observe the internal lithium plating state by disassembly. Therefore, it can only be judged non-destructively. However, the accuracy of judging lithium plating by voltage, time and capacity information is not high. Parameter abnormalities often appear only after a large-scale lithium plating, which makes it impossible to quickly judge the lithium plating problem of the cell.

[0037] In view of this, in order to overcome the shortcomings of related technologies, the battery cell in this embodiment incorporates... Figures 1 to 7 As shown, the overall design includes a housing containing the electrode assembly 3, a cover plate 2 connected to the housing, and a lithium plating detection structure 4.

[0038] The lithium plating detection structure 4 includes a reference post 401 disposed on the cover plate 2, and a reference electrode 403 electrically connected to the reference post 401 via a conductive component 402. The conductive component 402 is insulated from the electrode assembly 3, and from the cover plate 2. The reference electrode 403 is fixed to the outermost negative electrode sheet of the electrode assembly 3, near the negative electrode tab 302.

[0039] Therefore, by incorporating the lithium plating detection structure 4 within the battery cell, the reference post 401 is integrated onto the cover plate 2, without compromising the original sealing and internal structure of the battery cell. This ensures the basic performance of the battery cell while facilitating real-time lithium plating detection. Furthermore, the conductive component 402 is insulated from the electrode assembly 3 and the cover plate 2, preventing the reference post 403 from short-circuiting with other conductive components within the battery cell (such as the positive electrode and the casing).

[0040] Meanwhile, since the outermost negative electrode sheet of electrode group 3 is located near the negative electrode tab 302, which is the location where electrons accumulate significantly during the charging process of the battery cell and is the weakest point for lithium plating, setting the reference electrode 403 at this location can capture the lithium plating characteristic signal in the early stage of lithium plating. This allows for earlier detection of potential lithium plating problems, thereby improving the sensitivity of lithium plating detection and facilitating early warning.

[0041] Based on the above overview, specifically, let's continue to combine... Figures 1 to 7 As shown, typically, the cover plate 2 is provided with a positive terminal 201 and a negative terminal 202, which are located at both ends along the length of the cover plate 2. The cover plate 2 is also provided with an injection hole 203 and an explosion-proof valve 204. The electrode assembly 3 has a positive electrode tab 301 and a negative electrode tab 302, which are electrically connected to the positive terminal 201 and the negative terminal 202 respectively.

[0042] In some exemplary embodiments, for example, the reference post 401 is located between the positive post 201 and the negative post 202 on the cover plate 2, and is positioned close to the negative post 202. The reference post 401 is made of the same material as the negative post 202. This can shorten the electrical path, that is, shorten the overall length of the conductive component 402, which helps to ensure the stability of the detection signal.

[0043] In some exemplary embodiments, the reference post 401 is riveted to the cover plate 2, and the reference post 401 and the cover plate 2 are insulated from each other. This not only helps ensure the reliability of the connection between the reference post 401 and the cover plate 2, but also avoids the formation of a conductive path between the reference post 401 and the cover plate 2. In specific implementations, the reference post 401 can be a columnar structure or a rectangular structure, and the reference post 401 can be riveted to the cover plate 2 in the same way as the positive post 201 or negative post 202 in the prior art. In addition, it is worth noting that, while ensuring the reliability of the connection with external devices such as voltmeters, the contact area between the reference post 401 and the cover plate 2 can be set smaller than the contact area between the negative post 202 and the cover plate 2 to save space on the cover plate 2.

[0044] Combination Figures 4 to 6As shown, in some exemplary embodiments, the conductive component 402 includes, for example, a conductive element 4021 and an electronic insulating layer 4022 covering the outer peripheral surface of the conductive element 4021. The electronic insulating layer 4022 can be, for example, a lithium salt-containing polymer or a membrane. The lithium-containing polymer can be coated and dried, or subjected to in-situ polymerization initiated by ultraviolet light or heat. The membrane is made of conventional polyethylene or polypropylene material, wrapping the conductive element 4021. This provides good insulation between the conductive component 402 and the unit, preventing short circuits. The conductive element 4021 is made of one of copper, aluminum, and silver. In specific embodiments, the conductive element 4021 is, for example, made of metal wire. These materials give the conductive element 4021 excellent conductivity.

[0045] Reference Figure 4 As shown, in some exemplary embodiments, the reference electrode 403 is, for example, columnar and has a first metal base 4031, a first active material layer 4032, and a first electronic insulating layer 4033 arranged sequentially from the inside out. The first metal base 4031 is electrically connected to the conductive component 402, the first active material layer 4032 covers the outer surface of the first metal base 4031, and the first electronic insulating layer 4033 covers the outer surface of the first active material layer 4032.

[0046] The reference electrode 403 adopts a columnar structure, which makes the bottom of the first metal base 4031 electrically connected to the conductive component 402 for conducting the detection circuit. The first active material layer 4032 can reflect the lithium ion concentration and potential changes near the negative electrode tab 302. The first electronic insulating layer 4033 can prevent the reference electrode 403 from directly conducting with the negative electrode sheet and prevent electrons from passing through the negative electrode tab 302.

[0047] In specific implementation, the material of the first metal base 4031 can be the same as that of the conductive element 4021 in the conductive component 402. The first metal base 4031 can be made into a separate component and then connected to the conductive element 4021. Of course, it can be understood that the first metal base 4031 can be the part of the conductive element 4021 away from the reference post 401.

[0048] The first active material layer 4032, for example, adopts the negative electrode active material on the negative electrode sheet in the prior art, which includes, for example, a negative electrode active material, a binder and a conductive agent, wherein, for example, the mass percentage of the negative electrode active material is 60-90%, the mass percentage of the binder is 5-20%, and the mass percentage of the conductive agent is 5-20%, and the negative electrode active material is preferably lithium titanate.

[0049] The first electronic insulating layer 4033 is, for example, the same as the electronic insulating layer 4022 wrapped around the conductive element 4021 in the conductive component 402. It can be a lithium salt-containing polymer or a diaphragm. The coating method of the lithium-containing polymer can be coating and drying, ultraviolet-initiated or heat-initiated in-situ polymerization. The diaphragm is made of conventional polyethylene or polypropylene material and wraps around the conductive element 4021. This can make the conductive component 402 and the unit better insulated to avoid short circuit.

[0050] In some exemplary embodiments, the first metal substrate 4031 is filamentous, with a diameter D, for example, between 10 μm and 50 μm. Furthermore, the axial dimension L of the first active material layer 4032 on the first metal substrate 4031 is between 0.5 cm and 1.0 cm. Limiting the diameter of the first metal substrate 4031 not only prevents breakage due to excessively thin diameter, making processing difficult, but also prevents damage to the electrode assembly 3 due to excessively large diameter. Limiting the axial dimension of the first active material layer 4032 on the first metal substrate 4031 not only ensures that the reference electrode 403 has sufficient active area, but also avoids excessive volume that could affect the use of the electrode assembly 3.

[0051] In specific implementations, the diameter D of the first metal substrate 4031 is set to, for example, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm. The axial dimension L of the first active material layer 4032 of the first metal substrate 4031 is set to, for example, 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, or 1.0 cm.

[0052] Reference Figure 5 As shown, in some exemplary embodiments, the reference electrode 403 is, for example, sheet-like and has a second metal substrate 4034, a second active material layer 4035, and a second electronic insulating layer 4036. The second metal substrate 4034 is electrically connected to the conductive component 402, the second active material layer 4035 covers the outer peripheral surface of the second metal substrate 4034, and the second electronic insulating layer 4036 covers the outer surface of the second active material layer 4035.

[0053] At this point, the reference electrode 403 adopts a sheet-like structure, allowing the bottom 4034 of the second metal substrate to be electrically connected to the conductive component 402 for conducting the detection circuit. The second active material layer 4035 can reflect the lithium ion concentration and potential changes near the negative electrode tab 302, and the second electronic insulating layer 4036 can also prevent the reference electrode 403 from directly conducting with the negative electrode sheet, preventing electrons from passing through the negative electrode tab 302. Moreover, the sheet-like structure is beneficial for increasing the contact area, better capturing lithium plating characteristic signals, and improving the lithium plating detection sensitivity. Furthermore, the sheet-like structure of the reference electrode 403 can also increase the area of ​​the second active material layer 4035, which is beneficial for improving its service life.

[0054] In some exemplary embodiments, the thickness of the second metal substrate 4034 is between 5 μm and 30 μm. Limiting the thickness of the second metal substrate 4034 here prevents difficulties in fabrication due to insufficient thickness or damage to the electrode sheet due to excessive thickness during implantation into the electrode assembly 3. In specific embodiments, the thickness of the second metal substrate 4034 can be set to, for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, or 30 μm.

[0055] Combination Figure 6 and Figure 7 As shown, in some exemplary embodiments, the reference electrode 403 may also have the following structure: for example, the reference electrode 403 includes a mesh metal substrate 4037, a third active material layer, and a third electronic insulating layer 4038. The mesh metal substrate 4037 is electrically connected to the conductive component 402, the third active material layer covers the outer peripheral surface of the mesh metal substrate 4037, and the third electronic insulating layer 4038 covers the outer peripheral surface of the third active material layer.

[0056] Here, the reference electrode 403 adopts a structure consisting of a mesh metal base 4037, a third active material layer, and a third electronic insulating layer 4038. The mesh metal base 4037 is electrically connected to the conductive component 402 for conducting the detection circuit. The third active material layer reflects the lithium-ion concentration and potential changes near the negative electrode tab 302, and the third electronic insulating layer 4038 prevents direct conduction between the reference electrode 403 and the negative electrode sheet, preventing electrons from passing through the negative electrode tab 302. Furthermore, this structure, compared to a columnar structure, can load more active material, increasing its lifespan; compared to a sheet structure, it occupies less volume, reducing the amount of active material used.

[0057] In some exemplary embodiments, the thickness of the mesh metal substrate 4037 is, for example, set between 10 μm and 30 μm, and the mesh size of the mesh metal substrate 4037 is between 50 mesh and 200 mesh. In this case, the limited thickness of the mesh metal substrate 4037 and the limited mesh size allow for the loading of more active material, improving service life, while also ensuring the structural strength of the reference electrode 403. Furthermore, the limited porosity balances the amount of active material used and the volume occupied.

[0058] In specific implementations, the thickness of the mesh metal substrate 4037 can be set to, for example, 10μm, 15μm, 20μm, 25μm, or 30μm. The mesh size of the mesh metal substrate 4037 can be set to, for example, 50 mesh, 100 mesh, 150 mesh, or 200 mesh.

[0059] It is worth noting that the second metal substrate 4034 is made of the same material as the first metal substrate 4031, which is also the same material as the conductive element 4021. The second metal substrate 4034 can be made of, for example, copper, aluminum, or silver. The mesh metal substrate 4037 is also made of the same material as the first metal substrate 4031 and the conductive element 4021. The mesh metal substrate 4037 is, for example, composed of multiple interwoven metal wires forming a mesh. The second active material layer 4035 and the third active material layer are the same as the first active material layer 4032, all using the negative electrode active material from the negative electrode sheet. The second electronic insulating layer 4036 and the third electronic insulating layer 4038 are the same as the first electronic insulating layer 4033, and can be made of lithium salt-containing polymers or a separator.

[0060] Additionally, it is worth noting that the reference electrode 403 can be implanted in the outermost negative electrode sheet of the electrode assembly 3 near the negative electrode tab 302 during the preparation of the electrode assembly 3. Specifically, after the lamination is completed, the reference electrode 403 is placed in the outermost negative electrode sheet near the negative electrode tab 302, and a diaphragm is provided on both the outer side of the reference electrode 403 and the outer side of the outermost negative electrode sheet. Then, for example, hot pressing is used to solidify the electrode, thereby implanting the reference electrode 403 into the electrode assembly 3.

[0061] Furthermore, it is worth noting that, regarding this embodiment, based on the above exemplary implementations, in specific implementations, as a preferred embodiment, it is still […]. Figures 1 to 7As shown, it includes a housing, a cover plate 2, and a lithium plating detection structure 4. The housing contains an electrode assembly 3, and the cover plate 2 is fixed to the housing, for example, by welding. The lithium plating structure includes a reference post 401 and a reference electrode 403, which are electrically connected via a conductive component 402. The reference post 401 is fixed to the cover plate 2 by riveting and is insulated from the cover plate 2. The reference electrode 403 is fixed to the outermost negative electrode sheet of the electrode assembly 3 near the negative electrode tab 302.

[0062] The reference post 401 is located between the positive post 201 and the negative post 202 on the cover plate 2, and is positioned close to the negative post 202. The reference post 401 is made of the same material as the negative post 202. Furthermore, the conductive component 402 includes a conductive element 4021 and an electronic insulating layer 4022 covering the outer periphery of the conductive element 4021. The conductive element 4021 is made of one of copper, aluminum, or silver.

[0063] The reference electrode 403 is columnar and has a first metal base 4031, a first active material layer 4032, and a first electronic insulating layer 4033 arranged sequentially from the inside out. The first metal base 4031 is electrically connected to the conductive component 402. The first active material layer 4032 and the first electronic insulating layer 4033 cover the outer surface of the first metal base 4031. The diameter D of the first metal base 4031 is between 10 μm and 50 μm, and the axial dimension L of the first active material layer 4032 of the first metal base 4031 is between 0.5 cm and 1.0 cm.

[0064] The reference electrode 403 is sheet-shaped and has a second metal substrate 4034, a second active material layer 4035, and a second electronic insulating layer 4036. The second metal substrate 4034 is electrically connected to the conductive component 402. The second active material layer 4035 covers the outer peripheral surface of the second metal substrate 4034, and the second electronic insulating layer 4036 covers the outer surface of the second active material layer 4035. Furthermore, the thickness of the second metal substrate 4034 is between 5 μm and 30 μm.

[0065] The reference electrode 403 includes a mesh metal substrate 4037, a third active material layer, and a third electronic insulating layer 4038. The mesh metal substrate 4037 is electrically connected to the conductive component 402. The third active material layer covers the outer peripheral surface of the mesh metal substrate 4037, and the third electronic insulating layer 4038 covers the outer peripheral surface of the third active material layer. Furthermore, the thickness of the mesh metal substrate 4037 is between 10 μm and 30 μm, and the mesh size of the mesh metal substrate 4037 is between 50 mesh and 200 mesh.

[0066] In this embodiment, during specific testing, the battery cell is used to determine whether lithium plating has occurred inside the cell by measuring the voltage between the reference post 403 and the negative post 202 using a voltmeter. When the voltage is less than zero, it is determined that lithium plating has occurred.

[0067] In the above preferred embodiments, the specific setting and arrangement of the reference electrode 403, its structural shape, material, etc., can still be referred to the descriptions in the above exemplary embodiments. Furthermore, in this preferred embodiment, the beneficial effects brought about by the design of the reference electrode 403, its structural shape, material, etc., can also be referred to the descriptions in the above exemplary embodiments.

[0068] The battery cell in this embodiment adopts the above design. The lithium plating detection structure 4 not only preserves the original sealing and internal structure of the battery cell, but also facilitates real-time lithium plating detection while maintaining the cell's basic performance. Furthermore, by placing the reference electrode 403 near the negative electrode tab 302 on the outermost negative electrode sheet of the electrode group 3, lithium plating characteristic signals can be captured in the early stages of lithium plating. This allows for earlier detection of potential lithium plating problems, improving detection sensitivity and enabling early warning.

[0069] An embodiment of the second aspect of this application provides a battery pack having cells as described above.

[0070] The battery pack of this embodiment, by using the aforementioned cells, can achieve real-time lithium plating detection without damaging the original sealing structure and internal structure of the cells, ensuring the basic performance of the cells. Furthermore, it can capture lithium plating characteristic signals when lithium plating is in its early stages, thereby enabling earlier detection of potential lithium plating hazards, facilitating early warning, and ultimately improving the safety of the battery system.

[0071] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A battery cell, characterized in that: It includes a housing containing an electrode assembly, a cover plate connected to the housing, and a lithium plating detection structure; The lithium plating detection structure includes a reference post disposed on the cover plate and a reference electrode electrically connected to the reference post through a conductive component. The conductive component is insulated from the electrode group and from the cover plate. The reference electrode is fixed to the outermost negative electrode sheet of the electrode group near the negative electrode tab.

2. The battery cell according to claim 1, characterized in that: The reference post is located between the positive and negative posts on the cover plate, and is positioned close to the negative post; and the material of the reference post is the same as that of the negative post; and / or, The reference post is riveted and fixed to the cover plate, and the reference post and the cover plate are insulated from each other.

3. The battery cell according to claim 1, characterized in that: The conductive component includes a conductive element and an electronic insulating layer covering the outer peripheral surface of the conductive element. The conductive element is made of one of copper, aluminum, and silver.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The reference electrode is columnar and has a first metal base, a first active material layer and a first electronic insulating layer arranged sequentially from the inside to the outside. The first metal base is electrically connected to the conductive component, the first active material layer covers the outer surface of the first metal base, and the first electronic insulating layer covers the outer surface of the first active material layer.

5. The battery cell according to claim 4, characterized in that: The diameter D of the first metal substrate is between 10 μm and 50 μm; and / or, The axial dimension L of the first active material layer on the first metal substrate is between 0.5 cm and 1.0 cm.

6. The battery cell according to any one of claims 1 to 3, characterized in that: The reference electrode is sheet-shaped and has a second metal substrate, a second active material layer, and a second electronic insulating layer. The second metal base is electrically connected to the conductive component, the second active material layer covers the outer peripheral surface of the second metal base, and the second electronic insulating layer covers the outer surface of the second active material layer.

7. The battery cell according to claim 6, characterized in that: The thickness of the second metal substrate is between 5 μm and 30 μm.

8. The battery cell according to any one of claims 1 to 3, characterized in that: The reference electrode includes a mesh metal substrate bottom, a third active material layer, and a third electronic insulating layer; The bottom of the mesh metal base is electrically connected to the conductive component, the third active material layer covers the outer peripheral surface of the bottom of the mesh metal base, and the third electronic insulating layer covers the outer peripheral surface of the third active material layer.

9. The battery cell according to claim 8, characterized in that: The thickness of the mesh metal substrate is between 10μm and 30μm, and the mesh size of the mesh metal substrate is between 50 mesh and 200 mesh.

10. A battery pack, characterized in that: The battery pack includes the battery cell as described in any one of claims 1 to 9.

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