Reference electrode and lithium battery

Abstract

The application relates to the technical field of lithium batteries, and provides a reference electrode and a lithium battery. The reference electrode comprises a conductive layer and porous ion exchange membranes arranged on both sides of the conductive layer; the conductive layer comprises a plurality of wires arranged at intervals, the insulating layers at both ends of each wire are removed, and electrode insertion ends and electrode leading-out ends are respectively formed, the electrode insertion ends are arranged in a matrix, are fixed between the porous ion exchange membranes on both sides, and the electrode leading-out ends are led out from the same end of the porous ion exchange membranes on both sides and are gathered to a preset position. The reference electrode can utilize the plurality of electrode insertion ends arranged in a matrix and the corresponding electrode leading-out ends to form multi-channel multi-point potential measurement, so that the surface domain level potential distribution and measurement can be facilitated, and good use effect is achieved.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, and in particular to a reference electrode. This application also relates to a lithium battery having the aforementioned reference electrode. Background Technology

[0002] As is well known, the failure analysis and potential research of lithium-ion batteries cannot be separated from the "three-electrode" technology, which is an important means of measuring the reference electrode potential, used to analyze the lithium plating risk of high-current charging of batteries, and to study suitable fast charging safety strategies for vehicle charging.

[0003] Traditional reference electrodes typically involve removing the insulation from both ends of an insulating copper wire, leaving both ends as pure copper conductors. One end is embedded between the positive and negative electrodes inside the battery, while the other end is led out as a reference potential measurement lead. A small current is then used to charge the positive electrode and the reference, electroplating lithium ions from the positive electrode material onto the conductive end of the copper wire, thus completing the reference electrode with lithium metal as the reference potential. However, traditional reference electrodes can only perform single-point measurements and cannot achieve area-level potential distribution and measurement, necessitating further structural improvements. Utility Model Content

[0004] In view of this, this application aims to propose a reference electrode to facilitate the realization and measurement of potential distribution at the surface region level.

[0005] To achieve the above objectives, the technical solution of this application is implemented as follows: A reference electrode includes a conductive layer and a porous ion exchange membrane disposed on both sides of the conductive layer; The conductive layer includes multiple wires arranged at intervals. The insulating layer at both ends of each wire is removed to form an electrode insertion end and an electrode lead-out end, respectively. The electrode insertion ends are arranged in a matrix and fixed between the porous ion exchange membranes on both sides. The electrode lead-out ends are led out from the same end of the porous ion exchange membranes on both sides and converge to a preset position.

[0006] Furthermore, at least one side of the porous ion exchange membrane is provided with an adhesive coating, and the conductive layer is fixed to the porous ion exchange membrane by the adhesive coating.

[0007] Furthermore, the adhesive coating is made of polyvinylidene fluoride or polymethyl methacrylate.

[0008] Furthermore, the porous ion exchange membrane is made of PE or PP.

[0009] Furthermore, the porosity of the porous ion exchange membrane is between 20% and 70%.

[0010] Furthermore, the metal wire in the conductor is made of any one of copper, silver, nickel, gold, or platinum group metals.

[0011] Furthermore, the diameter of the metal wire is between 0.001 mm and 0.01 mm.

[0012] Furthermore, the portion of each wire located outside the porous ion exchange membrane is laid flat and fixed with adhesive tape.

[0013] Furthermore, the length L1 of the electrode insertion end is between 0.5mm and 10mm; and / or, the length L2 of the electrode lead-out end is between 0.5mm and 10mm.

[0014] Compared with related technologies, this application has the following advantages: (1) The reference electrode described in this application forms a three-layer integral structure through the conductive layer and the porous ion exchange membranes on both sides. The conductive layer includes multiple wires arranged at intervals. The electrode insertion ends of each wire are arranged in a matrix and implanted and fixed between the porous ion exchange membranes on both sides. The electrode lead-out ends of each wire are led out from the same end of the porous ion exchange membrane. This structure not only utilizes the porous ion exchange membranes arranged on both sides of the wire layer to improve the mechanical strength of the reference electrode, so that the reference electrode maintains a stable shape during use and ensures the stability of the reference electrode performance, but also allows the electrode lead-out ends to be led out from the same end of the porous ion exchange membranes on both sides and gathered to a preset position, which can facilitate connection with external circuits and improve the convenience of using the reference electrode. At the same time, the multiple electrode insertion ends and corresponding electrode lead-out ends arranged in a matrix can be used to form a multi-channel, multi-point potential measurement, which is conducive to realizing the potential distribution and measurement at the surface region level.

[0015] (2) An adhesive coating is provided on at least one side of the porous ion exchange membrane so that the conductive layer is bonded and fixed on the porous ion exchange membrane. This can improve the firmness of the bond between the conductive layer and the porous ion exchange membrane, prevent the conductive layer from shifting or falling off during use, and further enhance the structural stability of the reference electrode.

[0016] (3) The adhesive coating is made of polyvinylidene fluoride or polymethyl methacrylate. Both materials have good chemical stability and are not prone to reacting with the surrounding electrolyte or other chemicals, which can ensure the stability of the adhesive coating during long-term use, thereby ensuring the reliability of the connection between the conductive layer and the porous ion exchange membrane. At the same time, polyvinylidene fluoride or polymethyl methacrylate has appropriate adhesion, which can ensure that the conductive layer is firmly bonded to the porous ion exchange membrane and can ensure the ion transport performance of the ion exchange membrane.

[0017] (4) The porous ion exchange membrane is made of PE or PP, which can form a suitable pore structure, which is conducive to the diffusion and transport of ions.

[0018] (5) Limiting the porosity of porous ion exchange membranes not only provides sufficient space for ions to pass through, but also ensures that the ion exchange membrane has a certain mechanical strength and stability. At the same time, it can also avoid the mechanical strength of the ion exchange membrane being reduced due to excessively high porosity, and the ion transport efficiency being affected by excessively low porosity.

[0019] (6) The metal wire in the conductor is made of any one of copper, silver, nickel, gold and platinum group metals. These metals have good conductivity and chemical stability, which ensures the transmission efficiency of current in the conductor and also ensures the potential stability of the reference electrode during long-term use.

[0020] (7) Limiting the diameter of the metal wire can not only prevent the metal wire from breaking easily due to being too thin, but also prevent the electrode assembly from being damaged due to being too thick.

[0021] (8) The conductive parts located outside the porous ion exchange membrane are laid out flat and fixed with tape. This method can make the wires in this part neatly arranged and avoid the wires from getting tangled together, which is conducive to the normal operation of the reference electrode.

[0022] (9) Limiting the length of the electrode insertion end can ensure that the electrode insertion end has sufficient contact area, which is conducive to improving the measurement accuracy of the reference electrode; limiting the length of the electrode lead-out end can facilitate connection with external circuits on the one hand, and avoid wire management problems caused by excessively long lead-out ends on the other hand.

[0023] Another objective of this application is to provide a lithium battery in which a reference electrode is provided in the electrode assembly as described above, the reference electrode being located between the positive electrode and the negative electrode in the electrode assembly.

[0024] The lithium battery described in this application, by employing the aforementioned reference electrode, can utilize multiple electrode insertion ends and corresponding electrode lead-out ends arranged in a matrix to form a multi-channel, multi-point potential measurement, which is beneficial for realizing the potential distribution and measurement at the surface region level, and thus plays an important role in battery mechanism research and failure analysis. Attached Figure Description

[0025] 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 structure of the reference electrode described in the embodiments of this application; Figure 2This is a cross-sectional view of the reference electrode described in the embodiments of this application; Figure 3 This is a schematic diagram of the electrode insertion end as described in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of the electrode lead-out terminal described in the embodiment of this application; Figure 5 This is a schematic diagram of the application state of the reference electrode as described in the embodiments of this application; Figure 6 This is a cross-sectional view of the reference electrode application state as described in the embodiments of this application; Explanation of reference numerals in the attached figures: 1. Conductive layer; 2. Porous ion exchange membrane; 3. Adhesive tape; 4. Positive electrode; 5. Negative electrode; 100. Reference electrode; 101. Electrode insertion end; 102. Electrode lead-out end; 401. Positive electrode tab; 501. Negative electrode tab; 10. First conductor; 20. Second conductor; 30. Third conductor; 40. Fourth conductor; 50. Fifth conductor; 60. Sixth conductor; 70. Seventh conductor. Detailed Implementation

[0026] 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.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] An embodiment of the first aspect of this application provides a reference electrode that facilitates the realization and measurement of potential distribution at the surface region level.

[0033] In related technologies, the reference electrode is typically constructed by removing the insulation from both ends of a copper wire with an insulating layer, leaving both ends in a pure copper conductive state. One end is embedded between the positive and negative electrodes inside the battery, while the other end is led out of the battery as a reference potential measurement lead. A small current is then used to charge the positive electrode and the reference electrode, electroplating lithium ions from the positive electrode material onto the conductive end of the copper wire, ultimately completing the reference electrode with lithium metal as the reference potential.

[0034] However, traditional reference electrodes can only perform single-point measurements, and the implanted copper wires can move freely during battery manufacturing, making precise positioning impossible. Furthermore, the implanted copper wires are prone to breakage or snapping, resulting in poor reliability of the reference electrodes. Especially under the dynamic operation of large-size, high-rate batteries, they cannot meet the needs of research and development, and cannot achieve potential distribution and measurement at the surface region level.

[0035] In view of this, in order to overcome the shortcomings of the related technology, the reference electrode 100 in this embodiment is combined with Figures 1 to 6 As shown, the overall design includes a conductive layer 1 and a porous ion exchange membrane 2 disposed on both sides of the conductive layer 1.

[0036] The conductive layer 1 includes multiple wires arranged at intervals. The insulation layer at both ends of each wire is removed to form an electrode insertion end 101 and an electrode lead-out end 102, respectively. The electrode insertion ends 101 are arranged in a matrix and fixed between the porous ion exchange membranes 2 on both sides. The electrode lead-out ends 102 are led out from the same end of the porous ion exchange membranes 2 on both sides and are gathered to a preset position.

[0037] Thus, through the conductive layer 1 and the porous ion exchange membranes 2 on both sides, the reference electrode 100 forms a three-layer integral structure. The conductive layer 1 includes multiple wires arranged at intervals. The electrode insertion ends 101 of each wire are arranged in a matrix and implanted and fixed between the porous ion exchange membranes 2 on both sides. The electrode lead-out ends 102 of each wire are led out from the same end of the porous ion exchange membrane 2.

[0038] This structural design not only utilizes the porous ion exchange membranes 2 disposed on both sides of the conductor layer to improve the mechanical strength of the reference electrode 100, ensuring its stable shape during use and guaranteeing the stability of its performance, but also allows for convenient connection to external circuits by having the electrode leads 102 extended from the same end of the porous ion exchange membranes 2 on both sides and retracted to a preset position. This enhances the ease of use of the reference electrode 100. Furthermore, the matrix arrangement of multiple electrode insertion ends 101 and corresponding electrode leads 102 enables multi-channel, multi-point potential measurement, facilitating the realization of potential distribution and measurement at the surface region level.

[0039] Based on the above overview, specifically, refer to Figures 1 to 4 As shown, the reference electrode 100 in this embodiment includes a conductive layer 1 and a porous ion exchange membrane 2 disposed on both sides of the conductive layer 1. Figure 1 As shown, the conductive layer 1 includes multiple wires arranged at intervals, and the insulating layer at both ends of each wire is removed to form an electrode insertion end 101 and an electrode lead-out end 102, respectively.

[0040] For example, each wire includes multiple groups, and each group of wires includes a first wire 10, a second wire 20, a third wire 30, a fourth wire 40, a fifth wire 50, a sixth wire 60, and a seventh wire 70 of different lengths. The electrode insertion ends 101 of each wire are arranged in a matrix and fixed between the porous ion exchange membranes 2 on both sides, and the electrode lead-out ends 102 of each wire are led out from the same end of the porous ion exchange membranes 2 on both sides and brought together to a preset position.

[0041] It should be noted that, in addition to the seven wires of different lengths, each group of wires can also be configured with six, five, or other numbers of wires of different lengths. The specific configuration can be determined according to the battery size and actual needs; this embodiment does not impose any limitations on this. Furthermore, it should be noted that each electrode lead-out end 102 is retracted to a preset position. This preset position can be, for example, the end position along the length of the separator, or the middle position along the length of the separator. Figure 5 As shown, it is located in the middle of the positive electrode tab 401 and the negative electrode tab 501 of the electrode group.

[0042] To ensure the reliability of the conductive layer 1, in some exemplary embodiments, an adhesive coating is provided on at least one side of the porous ion exchange membrane 2, and the conductive layer 1 is fixed to the porous ion exchange membrane 2 by the adhesive coating. This bonding and fixing of the conductive layer 1 to the porous ion exchange membrane 2 improves the strength of the bond between the conductive layer 1 and the porous ion exchange membrane 2, prevents the conductive layer 1 from shifting or detaching during use, and further enhances the structural stability of the reference electrode 100.

[0043] In a specific implementation, as a preferred embodiment, an adhesive coating is provided on both sides of the porous ion exchange membrane 2, which can further improve the bonding strength between the conductive layer 1 and the porous ion exchange membrane 2, and further enhance the stability of the reference electrode 100.

[0044] In some exemplary embodiments, the adhesive coating is made of, for example, polyvinylidene fluoride (PVDF) or polymethyl methacrylate (PMMA). Alternatively, it can be made of PVDF with added ceramic powder, as is available in the prior art. This arrangement utilizes the appropriate adhesiveness of these materials to ensure a strong bond between the conductive layer 1 and the porous ion exchange membrane 2, thus guaranteeing the ion transport performance of the ion exchange membrane. Simultaneously, the excellent chemical stability of the materials themselves prevents them from reacting with the surrounding electrolyte or other chemicals, thereby ensuring the stability of the adhesive coating's performance during long-term use and ensuring the reliable connection between the conductive layer 1 and the porous ion exchange membrane 2.

[0045] In some exemplary embodiments, the porous ion exchange membrane 2 described above is made of materials such as PE or PP. These materials can form suitable pore structures that facilitate ion diffusion and transport.

[0046] In some exemplary embodiments, for example, the porosity of the porous ion exchange membrane 2 is between 20% and 70%. In specific embodiments, the porosity of the porous ion exchange membrane 2 can be set, for example, to 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%.

[0047] Here, limiting the porosity of the porous ion exchange membrane not only provides sufficient space for ions to pass through, but also ensures that the ion exchange membrane has a certain level of mechanical strength and stability. At the same time, it avoids the situation where excessively high porosity leads to a decrease in the mechanical strength of the ion exchange membrane, while excessively low porosity affects the ion transport efficiency.

[0048] Furthermore, in some exemplary embodiments, the metal wire in the aforementioned conductor is made of, for example, any one of copper, silver, nickel, gold, or platinum group metals. In this case, the good conductivity and chemical stability of these metals ensure the efficiency of current transmission in the conductor, while also guaranteeing the potential stability of the reference electrode 100 during long-term use. In specific implementations, copper wire is preferably used as the metal wire, as it possesses good conductivity and chemical stability while being relatively inexpensive.

[0049] Furthermore, in some exemplary embodiments, the diameter of the metal wire is, for example, between 0.001 mm and 0.01 mm. Specifically, the diameter of the metal wire can be set to, for example, 0.001 mm, 0.002 mm, 0.003 mm, 0.004 mm, 0.005 mm, 0.006 mm, 0.007 mm, 0.008 mm, 0.009 mm, or 0.01 mm. By limiting the diameter of the metal wire, not only can breakage due to an excessively thin wire be avoided, but damage to the electrode assembly due to an excessively thick wire can also be prevented during implantation.

[0050] Combination Figures 1 to 6 As shown, in some exemplary embodiments, for example, the portions of each wire located outside the porous ion exchange membrane 2 are laid flat and secured with tape 3. This method allows the wires in this portion to be neatly arranged, preventing them from tangling, and provides support and fixation, thereby facilitating the normal operation of the reference electrode 100.

[0051] Reference Figure 3 and Figure 4 As shown, in some exemplary embodiments, for example, the length L1 of the electrode insertion end 101 is between 0.5 mm and 10 mm, and the length L2 of the electrode lead-out end 102 is between 0.5 mm and 10 mm. Limiting the length of the electrode insertion end 101 ensures that it has sufficient contact area, which is beneficial for improving the measurement accuracy of the reference electrode 100. Limiting the length of the electrode lead-out end 102 facilitates connection to external circuits and avoids wire management problems caused by excessively long leads.

[0052] In specific implementations, the length L1 of the electrode insertion end 101 can be set to, for example, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, or 10mm. The length L2 of the electrode lead-out end 102 can also be set to, for example, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, or 10mm.

[0053] It is worth noting that, regarding the reference electrode 100 of this embodiment, based on the above exemplary embodiments, in specific implementation, as a preferred embodiment, it is still composed of... Figures 1 to 6 As shown, it may include, for example, a conductive layer 1 and porous ion exchange membranes 2 disposed on both sides of the conductive layer 1. The conductive layer 1 includes a plurality of spaced-apart wires, the insulating layers at both ends of each wire are removed to form an electrode insertion end 101 and an electrode lead-out end 102, respectively. The electrode insertion ends 101 are arranged in a matrix and fixed between the porous ion exchange membranes 2 on both sides, and the electrode lead-out ends 102 are led out from the same end of the porous ion exchange membranes 2 on both sides and converge to a predetermined position.

[0054] The porous ion exchange membrane 2 has an adhesive coating on at least one side, and the conductive layer 1 is fixed to the porous ion exchange membrane 2 by the adhesive coating. Preferably, the adhesive coating is made of polyvinylidene fluoride or polymethyl methacrylate.

[0055] The porous ion exchange membrane 2 is made of PE or PP, and its porosity is between 20% and 70%.

[0056] The metal wire in the conductor is made of any one of copper, silver, nickel, gold, or platinum group metals. Furthermore, the diameter of the metal wire is between 0.001 mm and 0.01 mm.

[0057] The portion of each wire located outside the porous ion exchange membrane 2 is laid flat and fixed with tape 3.

[0058] The length of the electrode insertion end 101 is between 0.5mm and 10mm, and the length of the electrode lead-out end 102 is between 0.5mm and 10mm.

[0059] In the specific fabrication of the reference electrode 100 in this embodiment, the insulation layers at both ends of multiple wires are first removed, and an electrode insertion end 101 and an electrode lead-out end 102 are formed respectively. The electrode insertion end 101 and the electrode lead-out end 102 are in a non-insulated state. The length of the wires is set differently according to the size of the battery and the measurement position.

[0060] Next, multiple wires are arranged in a certain order on one side of the porous ion exchange membrane 2, so that the electrode insertion ends 101 of each wire are arranged in a matrix and fixed by the adhesive coating on the porous ion exchange membrane 2 on that side. Then, the porous ion exchange membrane 2 on the other side is attached to the porous ion exchange membrane 2 with multiple wires implanted, forming a sandwich structure with wires in the middle and porous ion exchange membranes 2 on both sides. Then, the sandwich structure is bonded together by thermal bonding to form a sheet-like reference electrode 100.

[0061] In the above preferred embodiments, the specific settings and arrangements of the conductive layer 1, the porous ion exchange membrane 2, and the fixing method of the conductive layer 1 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 conductive layer 1, the porous ion exchange membrane 2, and the fixing method of the conductive layer 1 can also be referred to the descriptions in the above exemplary embodiments.

[0062] The reference electrode 100 in this embodiment adopts the above design, forming a three-layer integral structure through the conductive layer 1 and the porous ion exchange membranes 2 on both sides, with multiple wires arranged at intervals in the conductive layer 1.

[0063] An embodiment of the second aspect of this application provides a lithium battery, wherein the electrode assembly of the lithium battery is provided with a reference electrode 100 as described above, such as... Figure 5 and Figure 6 As shown, the reference electrode 100 is located between the positive electrode 4 and the negative electrode 5.

[0064] In practice, for example, the reference electrode 100 is placed between the required positive electrode 4 and negative electrode 5, and then thermo-pressed and cured using existing thermo-pressing processes, thus embedding the reference electrode 100 into the electrode assembly. After the battery is fabricated, lithium plating is performed according to conventional three-electrode measurement methods, and reference voltages at different locations are collected as needed.

[0065] In this embodiment, the battery, by employing the aforementioned reference electrode 100, can utilize multiple electrode insertion ends 101 arranged in a matrix and corresponding electrode lead-out ends 102 to form a multi-channel, multi-point potential measurement. This facilitates the realization of potential distribution and measurement at the surface region level, and thus plays an important role in battery mechanism research and failure analysis.

[0066] 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 reference electrode, characterized in that: It includes a conductive layer and a porous ion exchange membrane disposed on both sides of the conductive layer; The conductive layer includes multiple wires arranged at intervals. The insulating layer at both ends of each wire is removed to form an electrode insertion end and an electrode lead-out end, respectively. The electrode insertion ends are arranged in a matrix and fixed between the porous ion exchange membranes on both sides. The electrode lead-out ends are led out from the same end of the porous ion exchange membranes on both sides and converge to a preset position.

2. The reference electrode according to claim 1, characterized in that: An adhesive coating is provided on at least one side of the porous ion exchange membrane, and the conductive layer is fixed to the porous ion exchange membrane by the adhesive coating.

3. The reference electrode according to claim 2, characterized in that: The adhesive coating is made of polyvinylidene fluoride or polymethyl methacrylate.

4. The reference electrode according to claim 1, characterized in that: The porous ion exchange membrane is made of PE or PP.

5. The reference electrode according to claim 1, characterized in that: The porosity of the porous ion exchange membrane is between 20% and 70%.

6. The reference electrode according to claim 1, characterized in that: The metal wire in the conductor is made of any one of copper, silver, nickel, gold, or platinum group metals.

7. The reference electrode according to claim 6, characterized in that: The diameter of the metal wire is between 0.001 mm and 0.01 mm.

8. The reference electrode according to claim 1, characterized in that: The portion of each wire located outside the porous ion exchange membrane is laid flat and fixed with adhesive tape.

9. The reference electrode according to any one of claims 1 to 8, characterized in that: The length L1 of the electrode insertion end is between 0.5 mm and 10 mm; and / or, The length L2 of the electrode lead-out end is between 0.5mm and 10mm.

10. A lithium battery, characterized in that: The lithium battery electrode assembly includes a reference electrode as described in any one of claims 1 to 9, the reference electrode being located between the positive electrode and the negative electrode in the electrode assembly.

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