Three-electrode battery and its preparation method

Abstract

This invention relates to the field of battery technology and proposes a three-electrode battery and its fabrication method. The three-electrode battery includes: a casing having two large surfaces opposite each other and four side surfaces surrounding it, the four side surfaces closing an opening between the two large surfaces; an opening on one of the large surfaces and / or one of the side surfaces; a core pack located inside the casing; a reference electrode inserted into the casing through an opening; the reference electrode includes a fixing film and a copper wire disposed on the fixing film, the fixing film being disposed inside the core pack; the copper wire includes a first extension section and a second extension section, the first extension section being located inside the core pack and connected to the core pack, the second extension section being connected to the first extension section, and at least a portion of the second extension section extending from the opening to the outside of the casing; an electrolyte placed inside the casing; and an insulating sealing structure covering at least a portion of the opening. This three-electrode battery has a simple fabrication process, a high success rate in reference electrode implantation, and allows for performance analysis throughout its entire life cycle.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a three-electrode battery and its preparation method. Background Technology

[0002] With the rapid development of new energy, more and more lithium batteries are being used in new energy vehicles and energy storage applications. Therefore, it is particularly important to quickly assess the charging capacity of batteries. Currently, most battery charging capacity assessments are conducted through methods such as single cell testing, production line manufacturing of three-electrode batteries, and complete battery disassembly with implantation of three electrodes. However, these methods are time-consuming.

[0003] Manufacturing three electrodes on a production line takes at least one month, resulting in high time and cost. Full disassembly and implantation of three electrodes is not only complex but also has a low success rate. Moreover, current common three-electrode battery manufacturing is for the battery's BOL state (production line manufacturing). Once the battery is mass-produced and in service, it is no longer possible to manufacture corresponding three-electrode batteries for performance analysis. Summary of the Invention

[0004] This invention provides a three-electrode battery and its preparation method. The preparation process of the three-electrode battery is simple, the success rate of reference electrode implantation is high, and performance analysis can be performed throughout its entire life cycle.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] According to a first aspect of the present invention, a three-electrode battery is provided, comprising:

[0007] The housing has two large surfaces arranged opposite each other and four side surfaces arranged around it, the four side surfaces closing the opening between the two large surfaces; an opening is provided on one of the large surfaces and / or one of the side surfaces.

[0008] A core package, wherein the core package is located within the outer casing;

[0009] A reference electrode is inserted into the housing through the opening. The reference electrode includes a fixing film and a copper wire disposed on the fixing film. The fixing film is disposed inside the core package. The copper wire includes a first extension section and a second extension section. The first extension section is located inside the core package and connected to the core package. The second extension section is connected to the first extension section, and at least a portion of the second extension section extends out of the opening to the outside of the housing.

[0010] Electrolyte, wherein the electrolyte is placed inside the outer casing;

[0011] An insulating sealing structure that covers at least a portion of the opening.

[0012] According to a second aspect of the present invention, a method for preparing a three-electrode battery is provided, comprising:

[0013] The core pack is assembled inside the casing, and electrolyte is injected to form the initial battery;

[0014] The initial battery is then formed into a three-electrode battery;

[0015] The method for forming the initial battery into a three-electrode battery includes:

[0016] An opening is formed in the housing, the opening being located on a large face and / or one of the side faces of the housing;

[0017] A reference electrode is inserted into the housing through the opening. The reference electrode includes a fixing film and a copper wire disposed on the fixing film. The fixing film is disposed inside the core package. The copper wire includes a first extension and a second extension. The first extension is located inside the core package and connected to the core package. The second extension is connected to the first extension, and at least a portion of the second extension extends out of the opening to the outside of the housing.

[0018] An insulating sealing structure is provided on the surface of the housing, the insulating sealing structure covering at least a portion of the opening.

[0019] The three-electrode battery provided in this application is formed by breaking the casing of the initial battery and inserting a reference electrode. The three-electrode implantation method provided in this application has a short production cycle from start to finish, approximately 2 people / 2 days / 20 batteries. It is characterized by short cycle time, low cost, simple process, easy promotion, strong practicality, and high accuracy. This three-electrode battery is not limited by production line resources and can be extended to fields such as R&D failure analysis, after-sales service, and competitor analysis. Using the three-electrode battery provided in this application, the charging performance of batteries throughout their entire life cycle and at any SOH (state of health) level can be analyzed, offering high flexibility. Moreover, the three-electrode battery provided in this application can solve the problem of accurately analyzing changes in charging performance after battery mass production, while also offering significant convenience and efficiency. Attached Figure Description

[0020] To better understand this disclosure, reference may be made to the embodiments shown in the following figures. Components in the figures are not necessarily to scale, and related elements may be omitted to emphasize and clearly illustrate the technical features of this disclosure. Additionally, related elements or components may have different arrangements as known in the art. Furthermore, in the figures, the same reference numerals denote the same or similar components in various figures. Wherein:

[0021] Figure 1A three-dimensional structural schematic diagram of a three-electrode battery provided in an embodiment of this application;

[0022] Figure 2 for Figure 1 A plan view of the structure;

[0023] Figure 3 for Figure 1 A plan view of the middle section structure;

[0024] Figure 4 for Figure 1 A second planar schematic diagram of the middle section structure;

[0025] Figure 5 for Figure 1 A third planar schematic diagram of the middle section structure;

[0026] Figure 6 for Figure 1 Another planar schematic diagram of the structure;

[0027] Figure 7 for Figure 1 Schematic diagram of the inner and outer shell structure;

[0028] Figure 8 A schematic flowchart illustrating the preparation method of the three-electrode battery provided in the embodiments of this application;

[0029] Figure 9 This is another schematic flowchart illustrating the preparation method of the three-electrode battery provided in the embodiments of this application;

[0030] Figure 10 A schematic diagram of the structure during the fabrication process of the three-electrode battery provided in the embodiments of this application;

[0031] Figure 11 A schematic diagram of the structure of the three-electrode battery preparation method provided in the embodiments of this application when an exhaust device is applied;

[0032] Figure 12 This is a schematic diagram of the three-electrode battery provided in the embodiments of this application during testing;

[0033] Figure 13 This is a potential diagram of a three-electrode battery during normal lithium plating.

[0034] Figure 14 A schematic diagram illustrating a successful case of lithium plating during charging of a three-electrode battery at room temperature;

[0035] Figure 15 This is a schematic diagram illustrating a failed case of lithium plating during charging of a three-electrode battery at room temperature.

[0036] The annotations in the attached figures are explained as follows:

[0037] 100. Outer shell; 110. Protective layer; 120. Aluminum layer; 130. PP layer; 200. Core package; 300. Reference electrode; 310. Fixing film; 320. Copper wire; 330. Adhesive component; 340. Reference electrode tab; 400. Insulating and sealing structure; 410. Insulating tape; 420. Insulating adhesive; 1. Positioning ruler; 2. Exhaust device; 21. First pressure plate; 22. Second pressure plate; 23. Locking bolt. Detailed Implementation

[0038] The technical solutions in the exemplary embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. The exemplary embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure. Therefore, it should be understood that various modifications and changes can be made to the exemplary embodiments without departing from the scope of protection of this disclosure.

[0039] In the description of this disclosure, unless otherwise expressly specified and limited, the terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term “multiple” refers to two or more; and the term “and / or” includes any and all combinations of one or more associated listed items. In particular, references to “the / described” object or “a” object are also intended to indicate one of a possible plurality of such objects.

[0040] Unless otherwise specified or stated, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0041] Furthermore, it should be understood that the directional terms such as "upper," "lower," "inner," and "outer" described in the exemplary embodiments of this disclosure are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the exemplary embodiments of this disclosure. It should also be understood that, in the context of a reference to an element or feature being connected to another element (one or more) "upper," "lower," "inner," or "outer," it can be directly connected to the other element (one or more) "upper," "lower," "inner," or "outer," or indirectly connected to the other element (one or more) "upper," "lower," "inner," or "outer" through an intermediate element.

[0042] Firstly, such as Figure 1 and Figure 2As shown, this application embodiment provides a three-electrode battery. The three-electrode battery includes: a casing 100, a core pack 200, a reference electrode 300, and an electrolyte. The casing 100 has two large surfaces opposite to each other and four side surfaces surrounding it, the four side surfaces closing the opening between the two large surfaces; one of the large surfaces has an opening (…). Figure 1 The dotted line in the diagram represents the cutting line, which forms the opening after cutting. The core package 200 is located inside the outer casing 100. The reference electrode 300 is inserted into the outer casing 100 through the opening. The reference electrode 300 includes a fixing film 310 and a copper wire 320 disposed on the fixing film 310. The fixing film 310 is disposed inside the core package 200. The copper wire 320 includes a first extension section and a second extension section. The first extension section is located inside the core package 200 and connects to the core package 200. The second extension section connects to the first extension section, and at least a portion of the second extension section extends from the opening to the outside of the outer casing 100. The electrolyte is placed inside the outer casing 100. An insulating sealing structure 400 covers at least a portion of the opening.

[0043] It is understandable that the opening can also be located on only one side. Alternatively, the opening can be located on both the main surface and the side. For example, the opening can be located on one main surface or one side simultaneously. Of course, depending on the design requirements, the opening can also be located on one main surface and two sides simultaneously, which will not be elaborated further. To reduce the complexity of packaging, it is preferable that the opening is located on only one main surface, such as... Figure 1 As shown, an exemplary embodiment of this application is illustrated with the opening located on a large surface.

[0044] It is worth noting that the three-electrode battery is formed by introducing a lithium metal reference electrode 300 as the third electrode into a complete battery. In the embodiments of this application, after the initial battery is formed, the battery casing 100 is broken, and a reference electrode 300 is added into the initial battery to form a three-electrode battery. This reference electrode 300 serves as the third electrode of the three-electrode battery. This third electrode works in conjunction with the positive and negative electrodes in the initial battery to facilitate the study of the electrochemical performance of lithium-ion batteries.

[0045] The three-electrode battery provided in this application embodiment is formed by breaking open the casing of the initially prepared battery and inserting a reference electrode 300. In related technologies, the fabrication of three electrodes requires tracking all processes from battery stacking to formation and capacity determination, resulting in a long cycle, high production line resource consumption, and high cost. The three-electrode implantation method provided in this application embodiment has a shorter cycle from start to finish, approximately 2 people / 2 days / 20 batteries. It is characterized by a short cycle, low cost, simple process, easy promotion, strong practicality, and high accuracy.

[0046] This three-electrode battery is not limited by production line resources and can be extended to fields such as R&D failure analysis, after-sales service, and competitor analysis. Using the three-electrode battery provided in this application embodiment, the charging performance of batteries throughout their entire life cycle and at any SOH (state of health) level can be analyzed, offering high flexibility. Furthermore, the three-electrode battery provided in this application embodiment can solve the problem of not being able to accurately analyze changes in charging performance after battery mass production, while also offering significant convenience and efficiency.

[0047] In one embodiment, the core package 200 is provided with a positive electrode tab and a negative electrode tab, at least a portion of which are located on the same side of the housing 100.

[0048] In one embodiment, such as Figure 3 As shown, at least a portion of the first extension section within the copper wire 320 is configured with multiple branches.

[0049] It should be noted that the three-electrode battery provided in this application embodiment has a multi-branched first extension section within the copper wire 320 to facilitate lithium plating. Specifically, by increasing the number of branches in the first extension section, the lithium plating surface area and the amount of lithium plating can be increased, thereby improving the lifespan of the three electrodes and enhancing the efficiency of related tests.

[0050] It is understandable that the number of forked segments within the first extension can be set according to the available quantities; for example, the number of forked segments can be two, three, or four. In a specific embodiment, the first extension includes three forked segments to avoid an excessive number of forked segments, which would increase the difficulty of assembly.

[0051] When the reference electrode 300 is formed using copper wire 320, the copper wire 320 is soaked in concentrated sulfuric acid and cleaned at least at the tip of the first extension section away from the second extension end.

[0052] In one embodiment, the three forked sections are exposed, and the remaining surface of the copper wire is covered with an enameled wire layer. It is understood that the enameled wire layer is grease-based, and the copper wire has an enameled wire layer except at the lithium-plated tip of the first extension section (which was removed by concentrated sulfuric acid).

[0053] It should be noted that this enameled wire layer can effectively protect the remaining areas of the copper wire 320. Specifically, the enameled wire layer at the second extension section can prevent the copper wire from reacting with air, preventing oxidation of the copper wire and thus avoiding a decrease in the conductivity of the copper wire.

[0054] In specific settings, such as Figure 3As shown, the shape of the fixation membrane 310 inside the reference battery can be varied. In one embodiment, the fixation membrane 310 is a square fixation membrane 310 to reduce the resistance of the reference battery entering the battery, thereby improving the convenience and feasibility of implantation.

[0055] It is worth noting that, in order to further reduce the resistance of the reference cell entering the battery, a guide portion can be provided on the side of the square fixing film 310 facing away from the opening. For example, the guide portion is as follows: Figure 4 The curved surface shown or as Figure 5 The inclined plane shown.

[0056] When using the fixing film 310, it can be cut to obtain the desired shape. After the fixing film 310 is cut, it needs to be vacuum dried in a vacuum environment for subsequent use.

[0057] It is worth noting that when fixing the fixing film 310 inside the outer casing 100, such as Figures 3 to 5 As shown, the fixed film 310 extends as far as possible from the edge of the electrode to near the geometric center of the electrode to ensure that the three bifurcated segments in the first extension section are located at the geometric center of the electrode, thereby reducing errors and facilitating the study of the electrochemical performance of lithium-ion batteries.

[0058] There are several possibilities when selecting the material for the fixing membrane 310. In one specific embodiment, the fixing membrane 310 is a separator to reduce the amount of material used to prepare the three-electrode battery and reduce assembly difficulty.

[0059] In one embodiment, such as Figure 3 As shown, the copper wire 320 is bonded to one side of the fixed film 310 by the adhesive 330 to improve the stability of the reference electrode 300 in the housing 100, thereby improving the stability of the prepared three-electrode battery and extending its service life.

[0060] The adhesive 330 needs to be resistant to electrolyte corrosion, high temperature, and have a certain degree of adhesion. For example, the adhesive 330 can be an extremely thin insulating tape, which can be a specially formulated tape. In one specific example, the insulating tape has a width of 5±1 mm and a moderate length.

[0061] When setting up the adhesive component 330, the number of the adhesive component 330 can be set according to requirements. For example, such as Figure 3 As shown, two pieces of insulating tape can be selected and spaced apart along the extension direction of the copper wire 320 to stably fix the copper wire 320 onto the fixing film 310.

[0062] In one embodiment, the insulating sealing structure 400 is at least one of insulating tape 410 or insulating adhesive 420.

[0063] In one specific embodiment, insulating tape 410 can be attached to the outer surface of the opening of the housing 100. Then, insulating adhesive 420 can be applied to the outer surface of the housing 100, and the insulating adhesive 420 covers the insulating tape 410 to prevent the insulating adhesive 420 from contacting the electrolyte inside the housing 100.

[0064] It is understandable that the aforementioned insulating tape 410 and insulating adhesive 420 both serve as insulating and sealing structures 400.

[0065] In one embodiment, the casing 100 is an aluminum-plastic film. It should be understood that, in this case, the three-electrode battery is a pouch battery, and the casing 100 is made of aluminum-plastic film.

[0066] like Figure 6 As shown, in this embodiment, the reference electrode 300 and the positive electrode tab are located on opposite sides of the housing 100. This structural arrangement prevents the problems of difficult packaging and overcrowding caused by placing too many components on the same side of the housing 100, thereby reducing the manufacturing difficulty and improving the stability of the resulting three-electrode battery.

[0067] like Figure 7 As shown, when the housing 100 is formed from an aluminum-plastic film, the housing 100 includes a multi-layer structure stacked together, such as a protective layer 110, an aluminum layer 120, and a PP layer 130.

[0068] Furthermore, it is worth noting that the opening of the outer casing 100 is very sharp and can easily cut the enameled wire around the copper wire 320. If the enameled wire of the copper wire 320 is damaged, it will cause the copper wire 320 to become conductive with the aluminum layer 120 in the aluminum-plastic film, resulting in lithium plating failure and thus manufacturing failure.

[0069] There are various protective measures that can be used when protecting copper wire 320.

[0070] Specifically, Method 1: Apply special adhesive tape to the opening of the outer casing 100, allowing the copper wire 320 to pass through the adhesive area, thus protecting the copper wire 320. Method 2: Apply special adhesive tape to the copper wire 320 at the intersection of the reference electrode 300 and the opening. Method 3: Apply adhesive to the copper wire 320 at the intersection of the reference electrode 300 and the opening.

[0071] Because the diameter of the copper wire 320 is too small, it is inconvenient to connect it directly to an external circuit. Therefore, in one embodiment, the three-electrode battery provided in this application also includes a reference tab 340 (e.g., Figure 12As shown in the diagram, the reference tab 340 is connected to the copper wire 320 outside the housing 100. This reference tab 340 provides a large and stable connection point for external circuits, thus facilitating the testing of the three-electrode battery.

[0072] In one specific embodiment, the reference tab 340 is formed of a conductive copper sheet, which is welded together with a copper wire 320.

[0073] In one embodiment, the core package 200 includes a positive electrode and a negative electrode, with a positive electrode tab leading out from the positive electrode and a negative electrode tab leading out from the negative electrode, and the positive and negative electrodes are alternately arranged, separated by a separator; a fixing membrane 310 is placed between one of the positive and negative electrodes and the separator, and a copper wire 320 is located on the side of the fixing membrane 310 facing the electrode.

[0074] Specifically, the core pack 200 includes a negative electrode sheet, a positive electrode sheet, and a separator, wherein the separator separates the positive and negative electrode sheets to prevent short circuits. Taking the negative electrode sheet as an example, the negative electrode sheet includes a foil and an active material coated on at least one side of the foil, with the uncoated portion of the foil forming tabs. During the formation of the core pack 200, multiple layers of tabs leading from the negative electrode sheet form the negative electrode tab portion, and similarly, multiple layers of tabs leading from the positive electrode sheet form the positive electrode tab portion.

[0075] Since the reference electrode 300 of the three-electrode battery needs to be a lithium electrode, the exposed copper wire 320 facilitates lithium plating after the battery is assembled. Compared with the positive and negative electrodes, the reference electrode 300 always serves as the cathode for electrodeposition of lithium metal. Lithium ions in the electrolyte can migrate through the separator and be reduced to lithium metal on the surface of the exposed copper wire 320, which is then deposited on the surface of the exposed copper wire 320 in the form of a plating layer. This allows the reference electrode 300 to serve as a reference for the potential value.

[0076] In one embodiment, please refer to... Figure 1 and Figure 2 The structure shown has an opening on a large surface; the large surface has two opposing first edges and two opposing second edges, the first edges and second edges being alternately arranged and connected; the opening extends along one first edge and at least one second edge. Specifically, the opening may extend along one first edge and one second edge, or it may extend along one first edge and two second edges.

[0077] When forming the opening, a sharp, insulated knife or similar tool can be used to cut the opening into the surface of the outer casing 100. It is worth noting that the position of the cut should ensure that the reference electrode 300 can be easily implanted, and that there is a certain distance between the cut and the side of the battery to ensure sufficient space for subsequent tape bonding and adhesive application.

[0078] When forming the opening, it can be cut along the bottom of the battery and one side edge, or, the opening can be cut along the bottom of the battery and both side edges, or, as... Figure 1 As shown by the dotted line inside, the smaller the cut area, the better, in principle.

[0079] Secondly, embodiments of this application provide a method for preparing a three-electrode battery. Please refer to... Figures 1 to 7 refer to Figure 8 and Figure 9 The method for preparing this three-electrode battery, as shown, includes:

[0080] Step S802: Assemble the core pack 200 inside the outer casing 100 and inject electrolyte to form the initial battery;

[0081] Step S804: Form the initial cell into a three-electrode cell;

[0082] Step S804: A method for forming a three-electrode cell from the initial cell, comprising:

[0083] Step S8042: An opening is formed in the outer casing 100, the opening being located on a large surface of the outer casing 100;

[0084] Step S8044: Insert a reference electrode 300 into the housing 100 through the opening. The reference electrode 300 includes a fixing film 310 and a copper wire 320 disposed on the fixing film 310. The fixing film 310 is disposed inside the core package 200. The copper wire 320 includes a first extension section and a second extension section. The first extension section is located inside the core package 200 and connected to the core package 200. The second extension section is connected to the first extension section, and at least a portion of the second extension section extends out of the opening to the outside of the housing 100.

[0085] Step S8046: An insulating sealing structure 400 is provided on the surface of the housing 100, the insulating sealing structure 400 covering at least a portion of the opening.

[0086] It is understandable that the opening can also be located on only one side. Alternatively, the opening can be located on both the main surface and the side. For example, the opening can be located on one main surface or one side simultaneously. Of course, depending on the design requirements, the opening can also be located on one main surface and two sides simultaneously, which will not be elaborated further. To reduce the complexity of packaging, it is preferable that the opening is located on only one main surface, such as... Figure 1 As shown, an exemplary embodiment of this application is illustrated with the opening located on a large surface.

[0087] It is worth noting that the three-electrode battery preparation method provided in this application embodiment is formed by introducing a lithium metal reference electrode 300 as a third electrode into a complete battery. After the initial battery is prepared, the battery casing 100 is broken, and the reference electrode 300 is added into the initial battery to form a three-electrode battery. This reference electrode 300 serves as the third electrode of the three-electrode battery. This third electrode works in conjunction with the positive and negative electrodes in the initial battery to facilitate the study of the electrochemical performance of lithium-ion batteries.

[0088] It should be noted that the three-electrode battery fabrication method provided in this application involves breaking the casing of the initially fabricated battery and inserting a reference electrode 300 into the broken-casing battery. In related technologies, the fabrication of three electrodes requires tracking all processes from battery stacking to formation and capacity determination, resulting in a long cycle, high production line resource consumption, and high cost. The three-electrode implantation fabrication method provided in this application has a shorter cycle from start to finish, approximately 2 people / 2 days / 20 batteries, with a short cycle, low cost, simple process, easy to promote, strong practicality, and high accuracy.

[0089] This three-electrode battery is not limited by production line resources and can be extended to fields such as R&D failure analysis, after-sales service, and competitor analysis. Using the three-electrode battery provided in this application embodiment, the charging performance of batteries throughout their entire life cycle and at any SOH (state of health) level can be analyzed, offering high flexibility. Furthermore, the three-electrode battery provided in this application embodiment can solve the problem of not being able to accurately analyze changes in charging performance after battery mass production, while also offering significant convenience and efficiency.

[0090] In one embodiment, before performing step S804, which forms the initial cell into a three-electrode cell, the preparation method further includes:

[0091] Discharge the initial battery to the specified discharge cutoff voltage.

[0092] It should be noted that during the preparation of the three-electrode battery, the initial battery needs to be discharged to the specified discharge cutoff voltage at the current specified by the battery manufacturer. The reason for discharging is to ensure the safety of the operators during the shell breaking process.

[0093] In one embodiment, before step S8044, when the reference electrode 300 is inserted into the housing 100 through the opening, the preparation method further includes: preparing the reference electrode 300; the method for preparing the reference electrode 300 includes:

[0094] The fixed membrane 310 was vacuum dried;

[0095] Immerse the tip of the 320 copper wire in concentrated sulfuric acid to remove the enameled wire layer;

[0096] The impregnated copper wire 320 is attached to the dried diaphragm to obtain the reference electrode 300.

[0097] For example, the diaphragm can be placed in a vacuum drying oven, vacuumed, and then dried.

[0098] Hereinafter, a specific method for preparing a three-electrode battery is provided. For example, a sharp, insulated knife or related tool is used to cut along the bottom and side edges of the battery (both located within a large surface). The cut should be made in a way that allows the reference electrode 300 to be easily implanted, and the cut should be made at a certain distance from the edge of the battery to ensure sufficient space for subsequent tape bonding and adhesive application.

[0099] Understandably, depending on the difficulty of implanting the reference electrode 300, one can choose to cut on both sides or three sides, and in principle, the smaller the cut area, the better.

[0100] The dried fixing film 310 is cut into a suitable size that can be easily inserted into the initial battery.

[0101] The three forked sections of the 320 copper wire and the welded joints of the copper strip were soaked in concentrated sulfuric acid and cleaned thoroughly. The remaining parts were coated with an enameled wire layer. Then, as... Figure 3 As shown, place the copper wire 320 at a suitable position on the fixing film 310; then select an extremely thin insulating tape (i.e., adhesive 330) that is resistant to electrolyte corrosion, high temperature, and has a certain degree of adhesion, cut it to a size with a width of 5±1mm and a suitable length, and then select two pieces of insulating tape 410 to fix the copper wire 320 on the fixing film 310.

[0102] In one embodiment, please combine Figure 1 refer to Figure 10 A method for inserting a reference electrode 300 into the housing 100 through an opening includes:

[0103] The reference electrode 300 is placed inside the core package 200 by positioning ruler 1, such that at least a portion of the second extension extends from the opening to the outside of the housing 100.

[0104] For example, after positioning the electrode in the appropriate location, a positioning ruler 1 can be inserted between the electrode and the separator, and then the electrode and the separator can be raised to a certain height to implant the reference electrode into the battery. It should be understood that the electrode can be a negative electrode or a positive electrode.

[0105] It should be noted that the positioning ruler 1 has a certain degree of hardness, which can facilitate the support of the electrode and the diaphragm, so as to facilitate the implantation of the reference electrode 300, thereby reducing the difficulty of preparation and improving the preparation efficiency.

[0106] In one specific embodiment, the positioning ruler 1 is an insulating and corrosion-resistant ruler with a rounded shape to prevent the positioning ruler 1 from scratching the inner electrode sheet of the core package 200, which can improve the yield of the prepared three-electrode battery, and can prevent the positioning ruler 1 from being corroded by the electrolyte, thereby improving the service life of the positioning ruler 1.

[0107] In one specific embodiment, the core package 200 includes a positive electrode sheet and a negative electrode sheet, which are separated by a separator; the reference electrode 300 is installed in the core package 200 between the 1 to 5 layers of negative electrode sheets near the inner surface of the outer shell 100 and their adjacent separators, and the first extension of the copper wire 320 contacts the negative electrode sheet.

[0108] Specifically, after opening the outer casing 100, any negative electrode plate of the battery cell can be located, preferably within the first 5 layers. The fewer the layers, the easier it is to insert the reference electrode 300, and the higher the success rate of its implantation. For example... Figure 10 As shown, after positioning the appropriate negative electrode, a 1-inch ultra-thin insulating and corrosion-resistant positioning ruler with an arc is inserted between the negative electrode and the separator; then the negative electrode and the separator are raised to a certain height, and then the reference electrode 300 is implanted into the battery.

[0109] Furthermore, it is understood that the electrode in contact with the copper wire 320 can be a negative electrode or a positive electrode. For example, the electrode is a negative electrode, that is, the reference electrode 300 is installed in the core package 200 between the 1 to 5 layers of negative electrode sheets near the inner surface of the outer shell 100 and its adjacent diaphragm.

[0110] Understandably, after the reference electrode 300 is embedded in the battery, it is necessary to confirm the path and position of the reference electrode 300 and perform related operations at the intersection of the reference electrode 300 and the opening. Method 1: Apply special adhesive tape to the opening of the casing 100, allowing the copper wire 320 to pass through the adhesive area, thus protecting the copper wire 320. Method 2: Apply special adhesive tape to the copper wire 320 at the intersection of the reference electrode 300 and the opening. Method 3: Apply adhesive to the copper wire 320 at the intersection of the reference electrode 300 and the opening.

[0111] In one embodiment, the method of forming an initial battery into a three-electrode battery further includes:

[0112] Before setting the insulating sealing structure 400 on the surface of the housing 100, by means of... Figure 2 The exhaust device 2 shown vents the gas that enters the outer casing 100 during the shell breaking process. This structural design ensures the safety of the manufactured three-electrode battery and the accuracy of testing.

[0113] In one embodiment, a method for venting the gas that enters the outer casing 100 during shell breakage via the venting device 2 includes:

[0114] Place the outer casing 100 with the exhaust device 2 into a vacuum drying oven and evacuate it until the air pressure inside the oven reaches -95 kPa to -90 kPa, for a duration of 10 to 20 seconds.

[0115] The above-mentioned venting method can maintain a good fit between the reference electrode 300 and the separator, while also removing trace amounts of air and moisture that enter the battery during implantation, thereby improving the structural performance of the prepared three-electrode battery and enhancing the accuracy of detection.

[0116] In one embodiment, such as Figure 11 As shown, the exhaust device 2 includes a first pressure plate 21, a second pressure plate 22, and connecting ears respectively disposed on the first pressure plate 21 and the second pressure plate 22 for connecting the first pressure plate 21 and the second pressure plate 22. A compression space for placing the outer casing 100 is formed between the first pressure plate 21 and the second pressure plate 22.

[0117] For example, the battery after the reference electrode 300 is assembled can be placed on the first pressure plate 21; then the second pressure plate 22 is placed on top, the size of the second pressure plate 22 should not touch the cut of the outer casing 100, then the exhaust device 2 is adjusted to a suitable force value to exhaust the gas that entered the outer casing 100 when the casing was broken, and then the battery is placed in a vacuum drying oven for vacuuming until the air pressure inside the oven reaches -95kpa to -90kpa, the duration is 10 to 20 seconds.

[0118] After completing the above steps, apply adhesive to the broken area (i.e., near the opening). Before applying adhesive, ensure the area is free of foreign objects and stains. Before applying adhesive, use an appropriate agent such as... Figure 1 The opening is sealed with a narrow insulating tape 410, and then an insulating adhesive 420 (such as...) is applied, which is resistant to high temperature and electrolyte corrosion, has strong adhesion and good airtightness. Figure 1 As shown, the insulating tape 410 and the surrounding area are coated. The insulating adhesive 420 (such as structural adhesive) should completely cover the tape area and ensure strong adhesion and airtightness.

[0119] In one embodiment, the connecting ears are connected via, for example... Figure 11 The locking bolt 23 shown adjusts the distance between the first pressure plate 21 and the second pressure plate 22. It should be understood that the distance between the connecting ears can also be adjusted using other structures, and this adjustment process can be manual, semi-automatic, or automatic, details of which will not be elaborated further.

[0120] In one embodiment, the preparation conditions for the three electrodes are: temperature 25℃±2℃ and dew point less than or equal to -30℃.

[0121] Operate in a room or glove box where the ambient temperature is controlled at 25℃±2℃ and the dew point is less than or equal to -30℃.

[0122] To prevent the copper wire 320 from shifting, in one embodiment, after the structural adhesive in the battery coating area has completely solidified, the method for forming the initial battery into a three-electrode battery further includes:

[0123] Copper sheets are welded to the exposed copper wire 320 outside the outer casing 100 to obtain the reference tab 340 (e.g. Figure 12 (As shown).

[0124] It should be noted that, because the diameter of the copper wire 320 is too small, it is inconvenient to directly connect it to an external circuit. Therefore, in one embodiment, the three-electrode battery provided in this application also includes a reference tab 340, which connects to the portion of the copper wire 320 located outside the housing 100. This reference tab 340 can provide a larger and more stable connection point for the external circuit, thereby facilitating the testing of the three-electrode battery.

[0125] In one specific embodiment, the reference tab 340 is formed of a conductive copper sheet, which is welded together with a copper wire 320.

[0126] In addition, after the three-electrode battery is manufactured, its success should be tested. For example, the following conditions should be considered to determine whether the three-electrode battery has been successfully manufactured:

[0127] First, test the resistance between the reference electrode 300 and the side of the battery casing. If the resistance is small (generally less than 5MΩ), it means that the reference electrode 300 is conducting with the casing, and the three-electrode battery manufacturing has failed. If the resistance is greater than 5MΩ, it means that the manufacturing is successful. If successful, the battery will be lithium plated.

[0128] Secondly, during the lithium plating process of a three-electrode battery, taking a plating current of 10μA as an example, the lithium potential change curve should be observed. After the charging voltage reaches the inflection point, the voltage should remain stable with minimal fluctuations, meeting the ideal threshold requirements. Figure 13 .

[0129] Thirdly: During the process of breaking open the battery casing, some batteries may inevitably be damaged or have sealing problems that allow air to enter, but some lithium plating may be normal. In this case, a boundary lithium plating test should be performed on the battery. The battery should be charged with the maximum rechargeable current specified by the manufacturer as the initial charging current. The initial current of the battery is defined as IMAX.

[0130] The test procedure is as follows: discharge the battery to empty at room temperature, and then charge the battery with IMAX current. Whenever the voltage of the three-electrode battery drops to 20mV, reduce the current by 1A and continue charging until the current drops to 0A or the charging voltage reaches the upper limit of the charging voltage specified by the manufacturer, then stop charging.

[0131] If successful, refer to Figure 14 By selecting the IMAX current to charge the battery, the charging SOC range of the IMAX current can be observed, abbreviated as SOCI1. Figure 14 As shown in the inner a interval. If the charging error of SOCI1 is less than the ideal threshold SOCx1, it indicates successful fabrication; at this point, it should also be observed that... Figure 14 If the error between current and charging SOC is less than the ideal value within the b-range, then the fabrication is successful.

[0132] Some examples of failures: Figure 15 As shown, SOCI1 has a large error, and the current-charging SOC correspondence also has a large error.

[0133] If the battery cell passes the edge resistance test, lithium plating test, and boundary lithium deposition test, it can be considered that the three-electrode battery with broken casing has been successfully manufactured; otherwise, it is considered a manufacturing failure.

[0134] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and exemplary embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

[0135] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of protection of this disclosure is limited only by the appended claims.

Claims

1. A three-electrode battery, characterized in that, include: The outer casing has two large surfaces arranged opposite each other and four side surfaces arranged around it, the four side surfaces closing the opening between the two large surfaces; A core package, wherein the core package is located within the outer casing; Electrolyte, wherein the electrolyte is placed inside the outer casing; The electrolyte, the core, and the outer casing form an initial battery, which is a battery with a full life cycle and in any healthy state. An opening is provided on one of the large faces and / or one of the side faces of the housing; the opening is located on the surface of the housing of the initial battery; A reference electrode is inserted into the housing through the opening. The reference electrode includes a fixing film and a copper wire disposed on the fixing film. The fixing film is disposed within the core package and is a square fixing film. The square fixing film has a guide portion on the side opposite to the opening, and the guide portion is an arc-shaped surface or a slope. The copper wire includes a first extension section and a second extension section. The first extension section is located within the core package and connected to the core package. At least a portion of the first extension section is multi-branched. The second extension section connects to the first extension section, and at least a portion of the second extension section extends from the opening to the outside of the housing. An insulating sealing structure that covers at least a portion of the opening.

2. The three-electrode battery according to claim 1, characterized in that, The first extension segment includes three bifurcated segments.

3. The three-electrode battery according to claim 2, characterized in that, The three forked segments are exposed, and the remaining portion of the copper wire has an enameled wire layer on its surface.

4. The three-electrode battery according to claim 1, characterized in that, The fixed membrane is a diaphragm.

5. The three-electrode battery according to any one of claims 1-3, characterized in that, The copper wire is bonded to one side of the fixed film using an adhesive.

6. The three-electrode battery according to any one of claims 1-3, characterized in that, The insulating sealing structure is at least one of insulating tape or insulating adhesive.

7. The three-electrode battery according to any one of claims 1-3, characterized in that, The outer shell is made of aluminum-plastic film.

8. The three-electrode battery according to claim 7, characterized in that, The core package has a positive electrode lug and a negative electrode lug, at least a portion of which are located on the same side of the outer casing. The reference electrode and the positive electrode lug are located on opposite sides of the outer casing.

9. The three-electrode battery according to claim 8, characterized in that, The core package includes a positive electrode and a negative electrode. The positive electrode tab extends from the positive electrode and the negative electrode tab extends from the negative electrode. The positive electrode and the negative electrode are alternately arranged and separated by a separator. The fixing membrane is placed between one of the positive and negative electrodes and the separator, and the copper wire is located on the side of the fixing membrane facing the electrode.

10. The three-electrode battery according to any one of claims 1-3, characterized in that, An opening is provided on one of the large surfaces; the large surface has two first edges and two second edges arranged opposite to each other, the first edges and the second edges being alternately arranged and connected; The opening extends along one of the first edges and at least one of the second edges.

11. A method for preparing a three-electrode battery, characterized in that, include: The core pack is assembled inside the casing, and electrolyte is injected to form the initial battery; The initial battery is a battery with a full life cycle and in any health state; The initial battery is then formed into a three-electrode battery; The method for forming the initial battery into a three-electrode battery includes: An opening is formed in the housing, the opening being located on a large face and / or a side face of the housing; A reference electrode is inserted into the housing through the opening. The reference electrode includes a fixing film and a copper wire disposed on the fixing film. The fixing film is disposed inside the core package. The fixing film is a square fixing film. The side of the square fixing film opposite to the opening has a guide portion. The guide portion is an arc-shaped surface or a bevel. The copper wire includes a first extension section and a second extension section. The first extension section is located inside the core package and connected to the core package. At least a portion of the first extension section is multi-branched. The second extension section is connected to the first extension section, and at least a portion of the second extension section extends from the opening to the outside of the housing. The protective layer is bonded to the surface of the copper wire, such that the protective layer is located at the intersection of the copper wire and the opening; An insulating sealing structure is provided on the surface of the housing, the insulating sealing structure covering at least a portion of the opening.

12. The method for preparing a three-electrode battery according to claim 11, characterized in that, Before forming the initial battery into a three-electrode battery, the preparation method further includes: Discharge the initial battery to the specified discharge cutoff voltage.

13. The method for preparing a three-electrode battery according to claim 12, characterized in that, Before the reference electrode is inserted into the housing through the opening, the preparation method further includes: preparing the reference electrode; the method for preparing the reference electrode includes: The fixed membrane is vacuum dried; Immerse the tip of the copper wire in concentrated sulfuric acid to remove the enameled wire layer; The impregnated copper wire is attached to the dried diaphragm to obtain the reference electrode.

14. The method for preparing a three-electrode battery according to any one of claims 11-13, characterized in that, A method for inserting a reference electrode into the housing through the opening includes: The reference electrode is placed inside the core package using a positioning ruler, such that at least a portion of the second extension extends from the opening to the outside of the housing.

15. The method for preparing a three-electrode battery according to claim 14, characterized in that, The positioning ruler is an insulated and corrosion-resistant ruler with a rounded shape.

16. The method for preparing a three-electrode battery according to claim 14, characterized in that, The core package includes a positive electrode and a negative electrode, which are separated by a separator. The reference electrode is installed between the 1st to 5th layers of the negative electrode and the adjacent separator inside the core package, near the inner surface of the outer shell. The first extension of the copper wire contacts the negative electrode.

17. The method for preparing a three-electrode battery according to any one of claims 11-13, characterized in that, The method for forming the initial battery into a three-electrode battery further includes: Before an insulating sealing structure is installed on the surface of the outer shell, the gas that enters the outer shell during the shell breaking is discharged through an exhaust device.

18. The method for preparing a three-electrode battery according to any one of claims 11-13, characterized in that, Methods for venting the gas that enters the outer shell during shell breaking using an exhaust device include: Place the outer casing with the exhaust device into a vacuum drying oven and evacuate it until the air pressure inside the oven reaches -95 kPa to -90 kPa, for a duration of 10 to 20 seconds.

19. The method for preparing a three-electrode battery according to claim 17, characterized in that, The exhaust device includes a first pressure plate, a second pressure plate, and connecting ears respectively disposed on the first pressure plate and the second pressure plate for connecting the first pressure plate and the second pressure plate. A compression space for placing the outer casing is formed between the first pressure plate and the second pressure plate.

20. The method for preparing a three-electrode battery according to claim 19, characterized in that, The distance between the first pressure plate and the second pressure plate is adjusted by locking bolts between the connecting ears.

21. The method for preparing a three-electrode battery according to any one of claims 11-13, characterized in that, The preparation conditions for the three electrodes are as follows: temperature 25℃±2℃, dew point less than or equal to -30℃.

22. The method for preparing a three-electrode battery according to any one of claims 11-13, characterized in that, The method for forming the initial battery into a three-electrode battery further includes: Copper sheets are welded to the exposed copper wires outside the housing to obtain a reference tab.

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