Battery cell, battery and power utilization device

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a battery cell which comprises a first pole piece, a diaphragm and a second pole piece which are sequentially wound, and the diaphragm is arranged between the first pole piece and the second pole piece; the areas of the second bending positions of the first pole piece and the second pole piece are of a single-face coating structure, and insulating gummed paper is adhered to the second bending positions, corresponding to the diaphragm, of the first pole piece and the second pole piece. According to the utility model, the insulating gummed paper is adhered to the second bending part of the first pole piece and the second pole piece corresponding to the diaphragm, so that the positive electrode and the negative electrode in the area are in a separated state and cannot react, the active material layer cannot expand to reduce the stress on the position, the risk of breakage of the pole pieces is reduced, and the safety performance of the battery cell is improved. In addition, the utility model also discloses a battery comprising the battery cell and an electric device.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery production and manufacturing, and specifically relates to an electric core, a battery and an electric device. Background Art

[0002] Nowadays, with the development of modern society and the enhancement of people's environmental awareness, more and more devices choose lithium-ion batteries as power sources, such as mobile phones, laptops, power tools and electric vehicles, which provides a broad space for the application and development of lithium-ion batteries.

[0003] Among them, the battery cell can be divided into a laminated battery cell and a wound battery cell. In the field of power lithium batteries, the wound battery cell is a common battery cell structure. However, the existing wound battery cell generates large internal stress during the cycle process. After the cycle, the electrode sheet is easy to break at the second fold, causing the battery cell to have a short circuit risk. Therefore, it is urgent to propose a new technical solution to solve the above problems. Utility Model Content

[0004] One of the purposes of the utility model is to provide a battery cell to address the deficiencies of the prior art, which prevents the electrode pieces from breaking by pasting insulating tape on the second bends of the first electrode piece and the second electrode piece corresponding to the diaphragm.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A battery cell comprises a first pole piece, a diaphragm and a second pole piece which are wound in sequence, wherein the diaphragm is arranged between the first pole piece and the second pole piece; the area of ​​the first pole piece and the second pole piece corresponding to the second bend is a single-sided coating structure, and the second bend of the first pole piece and the second pole piece corresponding to the diaphragm is pasted with insulating tape; as an improvement of the battery cell described in the utility model, the second bend of the first pole piece and the second pole piece corresponding to the diaphragm is an improved area, and the insulating tape is pasted on a side of the improved area close to the first pole piece; and / or, the insulating tape is pasted on a side of the improved area close to the second pole piece.

[0007] The first electrode sheet is a positive electrode sheet or a negative electrode sheet, and the second electrode sheet is a corresponding negative electrode sheet or a positive electrode sheet. The insulating tape can isolate the first electrode sheet and the second electrode sheet at the corresponding position from reacting, thereby preventing the active material from expanding, thereby reducing the stress on the first electrode sheet or the second electrode sheet, reducing the possibility of electrode sheet breakage, and increasing the safety of the battery cell.

[0008] As an improvement of the battery cell described in the utility model, the insulating tape is located in the middle area of ​​the improved area, and the distances from the two side edges of the insulating tape to the corresponding two side edges of the improved area are the same, that is, the insulating tape is in the middle of the improved area, ensuring that the insulating tape can block the movement of lithium ions and prevent positive and negative reactions.

[0009] As an improvement of the battery core described in the utility model, the thickness of the insulating tape is 1-80 μm.

[0010] As an improvement of the battery core described in the utility model, the width of the insulating tape in the first direction is 1-50 mm.

[0011] As an improvement of the battery cell described in the utility model, the length of the insulating tape in the second direction is the same as the width of the diaphragm in the first direction, and the first direction is perpendicular to the second direction; that is, the length of the insulating tape is equal to the first pole piece and the second pole piece.

[0012] As an improvement of the battery cell described in the utility model, the first pole piece includes a first metal foil and a first active material coated on the first metal foil, the first pole piece corresponding to the improved area is a first single-sided area, the first single-sided area is coated with the first active material facing the improved area, and the first single-sided area is a hollow foil structure on one side away from the improved area.

[0013] As an improvement of the battery cell described in the utility model, the second pole piece includes a second metal foil and a second active material coated on the second metal foil, the second pole piece corresponding to the improved area is a second single-sided area, the second single-sided area is coated with the second active material facing the improved area, and the side of the second single-sided area away from the improved area is a hollow foil structure.

[0014] The second purpose of the present utility model is to provide a battery, comprising the battery cell as described above.

[0015] The third object of the present utility model is to provide an electrical device comprising the battery as described above.

[0016] The beneficial effect of the utility model is that the battery cell of the utility model comprises a first pole piece, a diaphragm and a second pole piece which are wound in sequence, and the diaphragm is arranged between the first pole piece and the second pole piece; the area of ​​the first pole piece and the second pole piece corresponding to the second bend is a single-sided coating structure, and the second bend of the first pole piece and the second pole piece corresponding to the diaphragm is pasted with insulating adhesive tape. Since the first pole piece and the second pole piece are a single-sided coating structure at the second bend, during the cycle, the positive and negative electrodes react to cause the active material to expand, and the stress at the bend is large, causing the pole piece to be easily broken. The utility model blocks the movement of lithium ions between the positive and negative electrodes in this area by pasting insulating adhesive tape on one or both sides of the second bend of the first pole piece and the second pole piece corresponding to the diaphragm, thereby preventing the reaction between the pole pieces and preventing the expansion of the active material, thereby reducing the stress, reducing the possibility of breakage, and increasing the safety performance of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0018] Figure 1 It is a schematic diagram of a part of the structure of the battery cell in the first embodiment of the utility model.

[0019] Figure 2 It is a schematic diagram of the expanded structure of a part of the battery cell in the second embodiment of the present utility model.

[0020] Figure 3 It is a schematic diagram of the expanded structure of a part of the battery cell in the third embodiment of the present utility model.

[0021] The reference numerals are described as follows:

[0022] 1-first pole piece; 11-first metal foil; 12-first active material;

[0023] 2- diaphragm;

[0024] 3-second pole piece; 31-second metal foil; 32-second active material;

[0025] 4-Insulation tape;

[0026] 5-Vacancy;

[0027] A-first direction; B-second direction. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0030] Reference to "embodiment" in this application means that a particular feature, structure or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0031] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0032] In the embodiments of the present application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments.

[0033] The term "plurality" used in the present application refers to two or more (including two).

[0034] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0035] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode collector. The negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer. The negative electrode collector not coated with the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon, etc. In order to ensure that a large current can pass without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a winding structure or a laminated structure, and the embodiments of the present application are not limited thereto.

[0036] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety must also be considered.

[0037] For battery cells, the main safety hazard comes from the charging and discharging process. The charging and discharging process is mainly the movement of lithium ions. The inventors found that in most battery structures, the positive and negative electrodes corresponding to the second bend are single-sided coated structures. During charging and discharging, the positive and negative electrodes react and the active materials expand. Since they are at the bend, the stress they receive will be greater, causing the electrode sheets at this location to break easily. In view of this, the embodiment of the present application provides a technical solution, by pasting insulating tape on one or both sides of the diaphragm at the breakable location, a lithium ion broken bridge is formed to prevent the active material from expanding and reduce the possibility of electrode sheet breakage.

[0038] The following is combined with Figure 1-3 The utility model is further described in detail with specific implementation modes, but is not intended to limit the utility model.

[0039] Implementation Method 1

[0040] like Figure 1As shown, a battery cell comprises a first pole piece 1, a diaphragm 2 and a second pole piece 3 which are wound in sequence, the diaphragm 2 is arranged between the first pole piece 1 and the second pole piece 3, the second bending part of the first pole piece 1 and the second pole piece 3 corresponding to the diaphragm 2 is an improved area, the first pole piece 1 comprises a first metal foil 11 and a first active material 12 coated on the first metal foil 11, the improved area corresponding to the first pole piece 1 is a first single-sided area, the first single-sided area is coated with the first active material 12 facing the improved area, and the side of the first single-sided area away from the improved area is a hollow foil structure, the second pole piece 3 comprises a second metal foil 31 and a second active material 32 coated on the second metal foil 31, the improved area corresponding to the second pole piece 3 is a second single-sided area, the second single-sided area is coated with the second active material 32 facing the improved area, and the side of the second single-sided area away from the improved area is a hollow foil structure, and the improved area of ​​the diaphragm 2 is pasted with insulating tape 4.

[0041] In this embodiment, the first pole piece 1 is a positive pole piece and the second pole piece 3 is a negative pole piece. It can be understood that this selection is only for the convenience of explanation. In other embodiments, it can also be set that the first pole piece 1 is a negative pole piece and the second pole piece 3 is a positive pole piece. The principle is the same and no other corresponding changes are required.

[0042] The insulating tape 4 is used to prevent the movement of lithium ions at the corresponding battery cell, thereby preventing the active material of the first pole piece 1 at the second bend from expanding, reducing the stress it receives, preventing the pole piece from breaking, and increasing the safety of the battery cell.

[0043] Preferably, insulating tape 4 is pasted on both sides of the improved area close to the first pole piece 1 and close to the second pole piece 3; it can be understood that in some other embodiments, the side of the improved area close to the first pole piece 1 is pasted with insulating tape 4, or the side of the improved area close to the second pole piece 3 is pasted with insulating tape 4, which can also play the effect of isolating the movement of lithium ions, but the structure with insulating tape 4 pasted on both sides of the improved area is safer.

[0044] Preferably, the insulating tape 4 is located in the middle area of ​​the improved zone, and the distances from the two side edges of the insulating tape 4 to the corresponding two side edges of the improved zone are the same, that is, the insulating tape 4 is located in the middle of the improved zone; the thickness of the insulating tape 4 is 1-80μm, the width of the insulating tape 4 in the first direction A is 1-50mm, the length of the insulating tape 4 in the second direction B is the same as the width of the diaphragm 2 in the first direction A, the first direction A is perpendicular to the second direction B, and the setting of the position and size of the insulating tape 4 can further ensure the formation of the lithium ion broken bridge.

[0045] Implementation Method 2

[0046] like Figure 2As shown, what is different from the first embodiment is that in this embodiment, the insulating tape 4 is pasted on the second bending part of the second pole piece 3, which can more directly block the movement of lithium ions at the second bending part of the battery cell, further ensuring that no reaction occurs between the positive and negative electrodes, preventing the active material of the first pole piece 1 from expanding, reducing the possibility of the first pole piece 1 breaking, and increasing the safety performance of the battery cell.

[0047] It is understandable that, in some other embodiments, the insulating tape 4 is pasted on the second bend of the first pole piece 1, which can also prevent the movement of lithium ions at the second bend of the battery cell.

[0048] The other structures and functions are the same as those in the first embodiment and will not be described in detail here.

[0049] Implementation Method 3

[0050] like Figure 3 As shown, the difference from the first embodiment is that: the present embodiment does not have an insulating tape 4, and a vacancy 5 is provided at the second bending portion of the second pole piece 3, which directly causes it to lack a source of lithium ions, further ensuring the possibility of lithium ion bridge formation, thereby preventing the first pole piece 1 from breaking.

[0051] It is understandable that in some other embodiments, a vacancy 5 is provided at the second bending portion of the first pole piece 1, which can also ensure the formation of a lithium ion thermal break bridge.

[0052] The other structures and functions are the same as those in the first embodiment and will not be described in detail here.

[0053] Battery

[0054] A battery comprises the above-mentioned battery cell, and the battery can be a lithium ion battery, a sodium ion battery, a magnesium ion battery, etc.

[0055] Electrical devices

[0056] An electrical device, comprising the above-mentioned battery, wherein the electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0057] According to the disclosure and teaching of the above description, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by the technicians in this field on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and do not constitute any limitation to the utility model.

Claims

1. A battery cell, characterized in that: It comprises a first pole piece (1), a diaphragm (2) and a second pole piece (3) which are wound in sequence, wherein the diaphragm (2) is arranged between the first pole piece (1) and the second pole piece (3); The area at the second bending of the first pole piece (1) and the second pole piece (3) is a single-sided coating structure, and the second bending of the first pole piece (1) and the second pole piece (3) corresponding to the diaphragm (2) is pasted with insulating tape (4).

2. The battery cell according to claim 1, characterized in that: The second bending point of the first pole piece (1) and the second pole piece (3) corresponding to the diaphragm (2) is an improved area, and the insulating adhesive tape (4) is pasted on one side of the improved area close to the first pole piece (1); And / or, the insulating tape (4) is adhered to a surface of the improved area close to the second pole piece (3).

3. The battery cell according to claim 2, characterized in that: The insulating tape (4) is located in the middle area of ​​the improved area, and the distances from the two side edges of the insulating tape (4) to the corresponding two side edges of the improved area are the same.

4. The battery cell according to claim 1, characterized in that: The thickness of the insulating tape (4) is 1-80 μm.

5. The battery cell according to claim 1, characterized in that: The width of the insulating tape (4) in the first direction (A) is 1-50 mm.

6. The battery cell according to claim 5, characterized in that: The length of the insulating tape (4) in the second direction (B) is the same as the width of the diaphragm (2) in the first direction (A), and the first direction (A) is perpendicular to the second direction (B).

7. The battery cell according to claim 2, characterized in that: The first pole piece (1) comprises a first metal foil (11) and a first active material (12) coated on the first metal foil (11); the first pole piece (1) is a first single-sided area corresponding to the improved area; the first single-sided area is coated with the first active material (12) facing the improved area; and a side of the first single-sided area away from the improved area is a hollow foil structure.

8. The battery cell according to claim 2, characterized in that: The second pole piece (3) comprises a second metal foil (31) and a second active material (32) coated on the second metal foil (31); the second pole piece (3) is a second single-sided area corresponding to the improved area; the second single-sided area is coated with the second active material (32) facing the improved area; and the second single-sided area is a hollow foil structure on a side away from the improved area.

9. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 8.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 9.

Images