Three-electrode battery

Abstract

The utility model provides a three-electrode battery which comprises a shell, an electrode assembly and an upper cover assembly, the shell is connected with the upper cover assembly in an insulating manner, a terminal assembly is arranged on the upper cover assembly, and the terminal assembly is respectively connected with the shell and the upper cover assembly in an insulating manner; the electrode assembly is located in the shell, the electrode assembly comprises a positive plate, a diaphragm and a negative plate which are sequentially stacked, a reference electrode is arranged on the surface of the side, away from the negative plate, of the diaphragm, the reference electrode comprises a connecting part and a main body part, the main body part is fixed to the surface of the diaphragm, and the connecting part is connected with the main body part. The connecting part is provided with an auxiliary soldering lug, and the auxiliary soldering lug is used for connecting the terminal assembly. By optimizing the structure and the layout position of the reference electrode, the equivalence of the potential of the reference electrode to the potential of the negative electrode of the battery is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery manufacturing, and relates to a three-electrode battery. Background Art

[0002] Lithium-ion batteries have the advantages of high energy density, small size, long cycle life, high open-circuit voltage, and low self-discharge rate, and are widely used in various fields such as electronic products, electric vehicles, and energy storage. In order to better study the performance of the positive and negative electrodes and the cycle performance of the battery, a reference electrode for stabilizing the working electrode is usually introduced on the basis of a conventional two-electrode system. The introduction of the reference electrode provides a new method for non-destructive electrochemical analysis of the battery, can dynamically reflect the electrochemical reaction state of the battery, and helps to analyze and determine the changes of each electrode in the reaction process, and still has great potential in future research and even practical applications.

[0003] At present, the reference electrode in a large-size battery is usually placed at a local position of the battery, and can only represent the potential state of this local position, which has certain limitations. When manufacturing a three-electrode battery, a method of drilling holes in the cover plate or metal shell is adopted to form a path for the reference electrode to lead out from the inside of the battery to the outside. However, the above method is easy to damage the integrity of the battery, and the operation process is relatively complicated.

[0004] Therefore, it is very important to improve the equivalence of the reference electrode potential in the three-electrode battery during the battery research process and avoid damaging the battery shell at the same time. Summary of the Utility Model

[0005] Aiming at the deficiencies of the existing technology, the purpose of the utility model is to provide a three-electrode battery, which improves the equivalence of the reference electrode potential to the negative electrode potential of the battery by optimizing the structure and layout position of the reference electrode, has high stability and convenience in the application of large batteries, does not need to damage the battery shell structure, and avoids the problem of battery leakage that is prone to occur in the traditional reference electrode lead-out path.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] The utility model provides a three-electrode battery, which includes a shell, an electrode assembly and an upper cover assembly. The shell is insulated and connected to the upper cover assembly. A terminal assembly is arranged on the upper cover assembly, and the terminal assembly is insulated and connected to the shell and the upper cover assembly respectively. The electrode assembly is located inside the shell, and the electrode assembly includes a positive electrode sheet, a separator and a negative electrode sheet which are stacked in sequence. A reference electrode is arranged on the surface of the separator away from the negative electrode sheet. The reference electrode includes a connecting part and a main body part. The main body part is fixed on the surface of the separator, and an auxiliary solder pad is arranged on the connecting part. The auxiliary solder pad is used to connect the terminal assembly.

[0008] As a preferred technical solution of the present utility model, the connecting part includes a first conductive wire; the main body part includes at least one second conductive wire connecting the connecting part; the second conductive wire is in a curved shape or a straight shape.

[0009] In order to improve the equivalence of the reference electrode potential, the present utility model adjusts the shape and quantity of the second conductive wires constituting the main body part, so that the main body part covers the diaphragm surface to the greatest extent.

[0010] As a preferred technical solution of the present utility model, the second conductive wire is bonded and fixed on the diaphragm surface.

[0011] The present utility model fixes the reference electrode on the diaphragm surface to form a prefabricated reference electrode, enabling it to be completed synchronously with the fabrication of the electrode assembly. There is no need to disassemble the fixing tape of the electrode assembly and then insert the reference electrode, reducing the impact on the structure of the electrode assembly during the implantation process of the reference electrode and simplifying the battery preparation process.

[0012] As a preferred technical solution of the present utility model, the first conductive wire and the second conductive wire are independently copper wire, gold wire, platinum wire, silver wire or Li-Sn alloy wire respectively.

[0013] As a preferred technical solution of the present utility model, the diameters of the first conductive wire and the second conductive wire are independently 0.03 - 0.1 mm respectively.

[0014] As a preferred technical solution of the present utility model, the terminal assembly includes an embedded terminal, and the embedded terminal penetrates through the upper cover assembly and is partially located inside the housing.

[0015] An upper insulating layer and a lower insulating layer are arranged on the outer periphery of the embedded terminal.

[0016] The upper insulating layer is sleeved on the outer peripheral wall of the embedded terminal.

[0017] The lower insulating layer is located on the side of the upper cover assembly close to the electrode assembly and extends to the inner cavity wall of the housing.

[0018] The present utility model uses the upper insulating layer to achieve good insulation and sealing between the electrode terminal and the upper cover assembly, and the lower insulating layer to achieve effective insulation between the terminal assembly, the housing and the upper cover assembly, avoiding the problem of short circuit inside the battery.

[0019] As a preferred technical solution of the present utility model, the surface of the side of the embedded terminal close to the electrode assembly includes an insulating area and an electrode area, and the electrode area is connected to the auxiliary solder pad.

[0020] A side patch layer is further provided on the outer periphery of the electrode assembly, and the side patch layer covers at least the insulation area.

[0021] As a preferred technical solution of the present invention, the terminal assembly further includes an electrode pin, one end of the electrode pin is connected to the embedded terminal, and the other end is connected to the auxiliary solder pad.

[0022] A side patch layer is further provided on the outer periphery of the electrode assembly, and the side patch layer covers at least one side surface of the electrode pin and the embedded terminal close to the electrode assembly respectively.

[0023] By providing the side patch layer, the present invention realizes effective isolation between the electrode assembly, the housing and the electrode terminal.

[0024] As a preferred technical solution of the present invention, the reference electrode and the auxiliary solder pad are integrally formed.

[0025] In the present invention, the reference electrode and the auxiliary solder pad adopt an integrally formed structure, which improves the connection strength and stability, prevents the auxiliary solder pad from falling off when connected to the electrode terminal assembly, affects the electrical connection between the reference electrode and the terminal, and has a smooth transition at the connection, avoiding the problem of poor charge flow.

[0026] As a preferred technical solution of the present invention, an explosion-proof valve is further provided on the surface of the upper cover assembly.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] A three-electrode battery provided by the present invention uses the auxiliary solder pad on the reference electrode to reserve a welding part for connecting the terminal assembly, shortens the reserved length of the reference electrode, and can complete the connection between the reference electrode and the external circuit without damaging the battery housing or the upper cover assembly. It not only avoids the problem of liquid leakage, but also is conducive to simplifying the preparation process of the three-electrode battery. In addition, the reference electrode is arranged on the surface of the diaphragm, which improves the equivalence of the reference electrode potential to the negative electrode potential of the battery, avoids the situation of using a local position to represent the whole of a large battery in a traditional battery, and is more conducive to the evaluation of the negative electrode potential of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a top view of the reference electrode provided by a specific embodiment of the present invention;

[0030] Figure 2 is Figure 1 the front view of the reference electrode in

[0031] Figure 3 is a top view of the reference electrode provided by a specific embodiment of the present invention;

[0032] Figure 4 is Figure 3 the front view of the reference electrode in

[0033] Figure 5 the top view of the upper cover assembly provided by a specific embodiment of the present utility model;

[0034] Figure 6 the bottom view of the upper cover assembly provided by a specific embodiment of the present utility model;

[0035] Figure 7 the front view of the upper cover assembly provided by a specific embodiment of the present utility model;

[0036] Figure 8 is Figure 7 the enlarged partial view at position B in

[0037] Figure 9 the top view of the upper cover assembly provided by a specific embodiment of the present utility model;

[0038] Figure 10 the bottom view of the upper cover assembly provided by a specific embodiment of the present utility model;

[0039] Figure 11 the front view of the upper cover assembly provided by a specific embodiment of the present utility model;

[0040] Figure 12 is Figure 11 the enlarged partial view at position A in

[0041] Among them, 100 - upper cover assembly; 200 - diaphragm; 1 - reference electrode; 2 - auxiliary solder pad; 3 - embedded terminal; 4 - upper insulating layer; 5 - lower insulating layer; 6 - side patch layer; 7 - explosion-proof valve; 8 - electrode pin. Specific Embodiment

[0042] It should be understood that in the description of the present utility model, the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0043] It should be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0044] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0045] In a specific embodiment, the present invention provides a three-electrode battery, including a shell, an electrode assembly and an upper cover assembly 100, wherein the shell is insulated and connected to the upper cover assembly 100, and a terminal assembly is provided on the upper cover assembly 100, and the terminal assembly is insulated and connected to the shell and the upper cover assembly 100. The electrode assembly is located inside the shell, and the electrode assembly includes a positive electrode sheet, a separator 200 and a negative electrode sheet stacked in sequence. Figure 1 and Figure 2 As shown, a reference electrode 1 is provided on the surface of the side of the diaphragm 200 away from the negative electrode sheet. The reference electrode 1 includes a connecting portion and a main body portion. The main body portion is fixed on the surface of the diaphragm 200. An auxiliary welding piece 2 is provided on the connecting portion. The auxiliary welding piece 2 is used to connect the terminal assembly.

[0046] The shell is an open structure, and the upper cover assembly 100 is arranged at the open end of the shell and is insulated. The electrode assembly can be a stacked structure or a wound structure. When a stacked structure electrode assembly is adopted, the positive electrode sheet, the diaphragm 200 and the negative electrode sheet are stacked in sequence; when a wound structure electrode assembly is adopted, the positive electrode sheet, the diaphragm 200 and the negative electrode sheet are stacked in sequence and then wound and folded. The present invention does not make special requirements on the material and shape of the shell and the upper cover assembly 100. Any commonly used materials and selections in the field can be used. For example, the shell can be a square aluminum shell, and the upper cover assembly 100 can be a rectangular aluminum cover plate that matches the square aluminum shell; the shell can also be a cylindrical aluminum shell, and the upper cover assembly 100 can be a circular cover plate that matches the cylindrical aluminum shell.

[0047] It should be noted that the three-electrode battery also includes the necessary positive and negative terminal assemblies disposed on the upper cover assembly 100. The positive terminal assembly is electrically connected to the positive electrode sheet and is insulated from the housing and the upper cover assembly 100; the negative terminal assembly is electrically connected to the negative electrode sheet and is insulated from the housing and the upper cover assembly 100. However, the above content does not constitute the main improvement of the present invention. Those skilled in the art can adjust the specific structure and connection method based on the specific battery selection. The present invention does not impose any special requirements or specific limitations on this.

[0048] During the preparation process of the present invention, the connection portion of the reference electrode 1 is first connected to the auxiliary welding piece 2 to form a combined component. Then, the shape of the reference electrode 1 is prefabricated on the surface of the diaphragm 200 according to the design style requirements and fixed. Finally, the electrode assembly is made using the positive electrode sheet, the diaphragm 200 with the reference electrode 1, and the negative electrode sheet. The reference electrode 1 and the electrode assembly can be made simultaneously without disassembling the fixing tape of the electrode assembly and then inserting the reference electrode 1, thereby minimizing the adverse effects of inserting the reference electrode 1 on the structure of the electrode assembly. By prefabricating the reference electrode 1, the present invention no longer needs to destroy the battery shell structure, thus avoiding the corrosion of the glue by the electrolyte or poor sealing when the glue is used to seal the holes, thereby avoiding the occurrence of battery leakage and the like. At the same time, there is no need to protect the external reference electrode 1 in the subsequent processes of the battery, which reduces the influence of the lead wire of the reference electrode 1 on the subsequent processes.

[0049] In some embodiments, the connecting portion includes a first conductive wire; the main body includes at least one second conductive wire connected to the connecting portion; the second conductive wire is curved or straight. In order to improve the equivalence of the potential of the reference electrode 1, the present invention adjusts the shape and number of the second conductive wires constituting the main body so that the main body covers the surface of the diaphragm 200 to the greatest extent. In order to help those skilled in the art better understand the overall technical solution and working process of the present invention, the present invention exemplarily provides the following specific shape styles of the main body: (1) Figure 1 and Figure 2 As shown in FIG, the main body is formed by winding a single long conductive wire in an S-shaped circuitous manner, and the end of the long conductive wire is connected to the first conductive wire. By increasing the number of windings and reducing the winding spacing, the coverage area of the main body is increased; (2) as Figure 3 and Figure 4As shown, the main body is composed of multiple straight or curved second conductive filaments. The multiple second conductive filaments are arranged side by side on both sides of the first conductive filament, so that the ends of the second conductive filaments are connected to the first conductive filaments. By increasing the number of second conductive filaments and reducing the distance between two adjacent second conductive filaments, the coverage area of the main body is increased. It should be noted that the above description of the shape and style of the main body does not constitute a further limitation on the scope of protection of the utility model. That is, other shapes and styles disclosed in the prior art or not disclosed in the new technology can be used in the utility model, and are not limited to the specific shapes described above.

[0050] In addition, the present invention does not specifically limit the connection method between the first conductive wire and the auxiliary welding piece 2. Laser welding, ultrasonic welding or arc welding known to those skilled in the art can be used, or local melting (or refining) followed by stretching can be used.

[0051] In some embodiments, the second conductive filament is bonded to the surface of the separator 200. The conductive filament in the present invention is fixed to the surface of the separator 200 using insulating paper or tape. This not only improves the stability of the reference electrode 1 but also insulates the reference electrode 1 from the positive electrode sheet, thereby enhancing battery safety. The paper or tape is made of materials commonly used by those skilled in the art, and this is not a specific requirement for this invention.

[0052] Specifically, the first conductive wire and the second conductive wire are independently copper wire, gold wire, platinum wire, silver wire or Li-Sn alloy wire.

[0053] Furthermore, the diameters of the first conductive thread and the second conductive thread are independently 0.03 to 0.1 mm, for example, they can be 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm or 0.1 mm. The numerical range described in the present invention includes not only the point values listed above, but also any point values between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range.

[0054] In some embodiments, as Figures 5 - 8 and Figures 9 - 12As shown, the terminal assembly includes an embedded terminal 3, which passes through the upper cover assembly 100 and is partially located inside the shell. An upper insulating layer 4 and a lower insulating layer 5 are provided on the periphery of the embedded terminal 3. The upper insulating layer 4 is sleeved on the outer peripheral wall of the embedded terminal 3 and is used for insulation and sealing between the side wall surface of the electrode terminal and the upper cover assembly 100. The lower insulating layer 5 is located on the side of the upper cover assembly 100 close to the electrode assembly and extends to the inner cavity wall of the shell, which is used for effective insulation between the terminal assembly, the shell and the upper cover assembly 100. In addition, the terminal assembly is also insulated from the adjacent positive terminal assembly and / or negative terminal assembly respectively by the lower insulating layer 5. The present utility model does not specifically limit the material of the upper insulating layer 4 and the lower insulating layer 5. Insulating materials familiar to those skilled in the art can be used, including but not limited to polypropylene, polyethylene, polyamide, polycarbonate and modified polycyclopropane.

[0055] The present invention provides the following two connection schemes for the terminal assembly and the auxiliary soldering piece 2 according to the specific composition and structure of the terminal assembly:

[0056] (1) Figure 7 and Figure 8 As shown, the surface of one side of the embedded terminal 3 close to the electrode assembly includes an insulating area and an electrode area, the electrode area is connected to the auxiliary welding piece 2, and a side patch layer 6 is also provided on the periphery of the electrode assembly, and the side patch layer 6 at least covers the insulating area to achieve effective insulation of the electrode assembly from the shell and the terminal assembly respectively.

[0057] (2) Figure 11 and Figure 12 As shown, the terminal assembly also includes an electrode pin 8, one end of the electrode pin 8 is connected to the embedded terminal 3, and the other end is connected to the auxiliary welding piece 2. A side patch layer 6 is also provided on the periphery of the electrode assembly, and the side patch layer 6 at least covers the electrode pin 8 and the embedded terminal 3 on one side surface close to the electrode assembly, thereby realizing effective insulation of the electrode assembly from the shell and the terminal assembly respectively.

[0058] It should also be noted that when the necessary positive terminal assembly and negative terminal assembly are provided on the upper cover assembly 100, the positive terminal assembly and the negative terminal assembly also use the upper insulating layer 4 to achieve good insulation and sealing between each of them and the upper cover assembly 100, and through the lower insulating layer 5 and the side patch layer 6, effective insulation is achieved between the electrode assembly, the shell, the positive terminal assembly and the negative terminal assembly.

[0059] The present invention does not specifically limit the material of the side patch layer 6 , and insulating materials well known to those skilled in the art may be used, including but not limited to polypropylene, polyethylene, polyamide, polycarbonate, and modified polycyclopropane.

[0060] In some embodiments, the reference electrode 1 and the auxiliary solder pad 2 are integrally formed. The present utility model adopts a process of local melting (or refining) and then stretching to obtain an integrated component of the reference electrode 1 and the auxiliary solder pad 2, complete the prefabrication of the reference electrode 1, and then fix it on the separator 200 to fabricate the electrode assembly, effectively shortening the battery manufacturing process.

[0061] In some embodiments, an explosion-proof valve 7 is further provided on the surface of the upper cover assembly 100. When the battery temperature changes or other external impact forces cause a change in the internal air pressure of the battery, the explosion-proof valve 7 can produce a corresponding deformation to offset the change in the internal air pressure of the battery, so as to avoid the problem of the battery housing bursting.

[0062] The applicant declares that the above description is only the specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of within the technical scope disclosed by the present utility model fall within the protection scope and the disclosure scope of the present utility model.

Claims

1. A three - electrode battery, characterized in that, It includes a housing, an electrode assembly and an upper cover assembly. The housing is insulated and connected to the upper cover assembly. A terminal assembly is provided on the upper cover assembly, and the terminal assembly is insulated and connected to the housing and the upper cover assembly respectively; The electrode assembly is located inside the housing. The electrode assembly includes a positive electrode sheet, a separator and a negative electrode sheet stacked in sequence. A reference electrode is provided on a surface of the separator away from the negative electrode sheet. The reference electrode includes a connecting portion and a main body portion. The main body portion is fixed on the surface of the separator, and an auxiliary solder pad is provided on the connecting portion. The auxiliary solder pad is used to connect the terminal assembly.

2. The three-electrode battery according to claim 1, characterized in that, The connecting portion includes a first conductive wire; The main body portion includes at least one second conductive wire connecting the connecting portion; The second conductive wire is curved or straight.

3. The three-electrode battery according to claim 2, wherein, The second conductive wire is bonded and fixed on the surface of the separator.

4. The three-electrode battery according to claim 2, characterized in that, The first conductive wire and the second conductive wire are independently copper wire, gold, platinum wire, silver wire or Li-Sn alloy wire.

5. The three-electrode battery according to claim 2, characterized in that, The diameters of the first conductive wire and the second conductive wire are independently 0.03 to 0.1 mm.

6. The three-electrode battery according to claim 1, wherein The terminal assembly includes an embedded terminal. The embedded terminal penetrates through the upper cover assembly and is partially located inside the housing; An upper insulating layer and a lower insulating layer are provided on the outer periphery of the embedded terminal; The upper insulating layer is sleeved on the outer peripheral wall of the embedded terminal; The lower insulating layer is located on a side of the upper cover assembly close to the electrode assembly and extends to the inner cavity wall of the housing.

7. The three-electrode battery according to claim 6, characterized in that, A surface of the embedded terminal close to the electrode assembly includes an insulating area and an electrode area. The electrode area is connected to the auxiliary solder pad; A side patch layer is further provided on the outer periphery of the electrode assembly. The side patch layer at least covers the insulating area.

8. The three-electrode battery according to claim 6, wherein The terminal assembly further includes an electrode pin. One end of the electrode pin is connected to the embedded terminal, and the other end is connected to the auxiliary solder pad; A side patch layer is further provided on the outer periphery of the electrode assembly. The side patch layer at least covers the electrode pin and a surface of the embedded terminal close to the electrode assembly respectively.

9. The three-electrode battery according to claim 1, wherein The reference electrode and the auxiliary solder pad are integrally formed.

10. The three-electrode battery according to claim 1, characterized in that, An explosion-proof valve is further provided on the surface of the upper cover assembly.

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