Battery cell and battery

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a battery cell, which comprises a pole piece and a diaphragm which are sequentially wound, and is characterized in that the pole piece comprises a straight area, a first corner area and a second corner area which are mutually connected, and the first corner area and the second corner area are respectively positioned at two ends of the straight area; the length of the first corner area is greater than that of the second corner area; the first corner area is divided into a coating area and an empty foil area, the coating area and the empty foil area are arranged in a staggered manner, and at least part of the empty foil area extends out of the first corner area to be used as a tab. According to the utility model, the empty foil in the second corner area extends to serve as the tab, so that the flatness of the battery cell can be improved while the energy density of the battery cell is not influenced, and the possibility of failure of the battery cell due to deformation is further reduced. In addition, the utility model also discloses a battery comprising the battery cell.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery production and manufacturing, and specifically relates to an electric core and a battery. 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 stacked battery cell and a wound battery cell. In the field of power lithium batteries, the wound battery cell is more common and practical. At present, in the conventional winding structure, the conventional structure, the middle-positioned pole ear structure and the multi-pole ear structure, the pole piece surface needs to be designed with pole ears, and the pole piece surface and the corresponding pole piece position need to be pasted with adhesive tape. In addition, empty foil needs to be reserved next to and at the bottom of the pole ear, resulting in the existence of pole ear areas, empty foil adhesive tape areas, and material areas on the pole piece surface, which leads to the unevenness of the pole piece layer where the pole ear exists, so that the battery cell is prone to deformation, resulting in battery cell failure. 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 in view of the deficiencies of the prior art, which can maintain flatness by extending the empty foil in the first turning area as a pole ear, thereby reducing the possibility of battery cell failure due to battery cell deformation.

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

[0006] A battery cell, comprising a pole piece and a separator wound in sequence, wherein the pole piece comprises a straight region, a first corner region and a second corner region connected to each other, the first corner region and the second corner region are respectively connected to the straight region, and the length of the first corner region is greater than the length of the second corner region;

[0007] The first corner area is divided into a coating area and an empty foil area, the coating area and the empty foil area are arranged alternately, and at least a part of the empty foil area extends out of the first corner area to be used as a pole ear.

[0008] As an improvement of the battery cell described in the utility model, the length L1 of the first corner area and the length L2 of the pole piece structure satisfy the following relationship: L1 / L2=a, a is an adjustment constant, 1 / 3<a<2 / 3; when the number of layers of the battery cell is ≤20, 1 / 3<a<1 / 2; when the number of layers of the battery cell is >20, 1 / 2≤a<2 / 3. Since the second corner area is provided with the empty foil area, when the value of a is larger, the battery cell will lose more energy density, and when the value of a is smaller, the internal resistance of the battery cell will be larger. By limiting the value of a by the number of battery cell layers, the length of the first corner area is within a reasonable range of values, thereby ensuring the normal use of the battery cell.

[0009] As an improvement of the battery cell described in the utility model, the straight area and the second corner area have the same structure, both including metal foil and active material coated on the metal foil, and the active material coated in the straight area and the second corner area can make up for the loss of energy density caused by the empty foil area.

[0010] As an improvement of the battery cell described in the utility model, the pole piece is divided into a first pole piece and a second pole piece with opposite polarities, the direction in which the empty foil area in the first pole piece extends is opposite to the direction in which the empty foil area in the second pole piece extends, the first pole piece and the second pole piece are respectively extended with a first pole ear and a second pole ear, and the first pole ear and the second pole ear are both extended parts of the empty foil area.

[0011] As an improvement of the battery cell of the utility model, the first pole tab and the second pole tab are respectively arranged at two ends of the battery cell in the height direction and at two sides of the battery cell in the width direction.

[0012] As an improvement of the battery cell of the utility model, the first pole lug and the second pole lug are respectively arranged at two ends of the battery cell in the height direction and are respectively arranged on the same side of the battery cell in the width direction.

[0013] As an improvement to the battery cell described in the utility model, the first pole ear and the second pole ear are arranged at both ends of the battery cell in the height direction, and are respectively arranged on both sides of the battery cell in the width direction, avoiding the occurrence of a structure in which the first pole ear and the second pole ear are arranged on the same end and the same side, thereby preventing the battery cell from short-circuiting.

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

[0015] The beneficial effect of the utility model is that the battery cell of the utility model comprises a pole piece and a diaphragm wound in sequence, the pole piece comprises a straight area, a first corner area and a second corner area connected to each other, the first corner area and the second corner area are respectively connected to the straight area, the length of the first corner area is greater than the length of the second corner area; the first corner area is divided into a coating area and an empty foil area, the coating area and the empty foil area are arranged alternately, and at least part of the empty foil area extends out of the first corner area to serve as a pole ear. In the utility model, by extending the empty foil area as a pole ear, the flatness of the battery cell is ensured, and the failure of the battery cell due to deformation is prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0017] Figure 1 It is a schematic diagram of the structure of the first pole piece in the utility model.

[0018] Figure 2 It is a cross-sectional schematic diagram of the first pole piece in the utility model.

[0019] Figure 3 It is a structural schematic diagram of the second pole piece in the utility model.

[0020] Figure 4 This is one of the structural schematic diagrams of the battery cell in the utility model.

[0021] Figure 5 This is the second structural schematic diagram of the battery cell in the utility model.

[0022] Figure 6 This is the third structural schematic diagram of the battery cell in the utility model.

[0023] The reference numerals are described as follows:

[0024] 1-straight area; 21-coating area; 22-empty foil area; 3-second corner area; 4-metal foil;

[0025] 100-first pole piece; 101-first pole ear;

[0026] 200 - second pole piece; 201 - second pole ear;

[0027] H-height direction; W-width 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] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0033] In the present application, the battery cell may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, etc., and the embodiments of the present application are not limited thereto. The battery cell may be cylindrical, flat, rectangular or in other shapes, etc., and the embodiments of the present application are not limited thereto.

[0034] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. The battery generally includes a box for encapsulating one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[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 negative electrode current collector may be made of copper, and the negative electrode active material may be carbon or silicon. In order to ensure that a large current can pass without melting, the positive electrode tabs are multiple and stacked together, and the negative electrode tabs are multiple and stacked together. The material of the separator may be PP (polypropylene) or PE (polyethylene).

[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] The inventors found that in the existing battery cell structure, since the pole tabs are usually set in the middle of the pole piece or the head and tail of the pole piece, and need to be fixed by sticking the pole tab glue, the flatness of the wound battery cell is reduced. In view of this, the embodiment of the present application provides a technical solution, by setting an empty foil area at the bend of the battery cell and extending the empty foil area as a pole tab to ensure the flatness of the battery cell.

[0038] The following is combined with Figures 1 to 6 The utility model is further described in detail with specific implementation modes, but is not intended to limit the utility model.

[0039] A battery cell includes a pole piece and a diaphragm wound in sequence, the pole piece includes a straight area 1, a first corner area and a second corner area 3 connected to each other. It can be understood that the specific structure of the pole piece is: the straight area 1 is connected to the first corner area and / or the straight area 1 is connected to the second corner area 3; the length of the first corner area is greater than the length of the second corner area 3.

[0040] It should be noted that in this embodiment, the first corner area is the tail corner area of ​​the pole piece, and the second corner area 3 is the head corner area of ​​the pole piece. In the usual structure, the length of the head corner area is smaller than the length of the tail corner area. Therefore, in this embodiment, the structure of the first corner area is improved to further ensure the flatness of the battery cell.

[0041] Specifically, the first corner area is divided into a coating area 21 and an empty foil area 22, and the coating area 21 and the empty foil area 22 are arranged alternately. At least a portion of the empty foil area 22 extends out of the first corner area to serve as a pole ear. The straight area 1 has the same structure as the second corner area 3, both of which include a metal foil 4 and an active material coated on the metal foil 4. Compared with the conventional structure, the second corner area 3 and the straight area 1 in this embodiment do not need to reserve an empty foil structure for the welding of the pole ear, and the active material coated thereon can make up for the energy density loss caused by the setting of the empty foil area 22, so that the battery cell in this embodiment can improve the flatness without losing the energy density.

[0042] Specifically, the length L1 of the first corner area and the length L2 of the pole piece structure satisfy the following relationship: L1 / L2=a, a is an adjustment constant, 1 / 3<a<2 / 3, wherein, when the number of layers of the battery cell is ≤20, 1 / 3<a<1 / 2; when the number of layers of the battery cell is >20, 1 / 2≤a<2 / 3. Since the second corner area is provided with an empty foil area 22, when the value of a is larger, the battery cell will lose more energy density, and when the value of a is smaller, the internal resistance of the battery cell will be greater. By limiting the value of a by the number of battery cell layers, the length of the first corner area is within a reasonable range to ensure the normal use of the battery cell.

[0043] Specifically, the electrode piece is divided into a first electrode piece 100 and a second electrode piece 200 with opposite polarities. The direction in which the empty foil area 22 in the first electrode piece 100 extends is opposite to the direction in which the empty foil area 22 in the second electrode piece 200 extends. The first electrode piece 100 and the second electrode piece 200 are respectively extended with a first pole ear 101 and a second pole ear 201. It can be understood that the first pole ear 101 and the second pole ear 202 are both extended parts of the empty foil area 22.

[0044] In this embodiment, if Figure 4 As shown, the first electrode tab 101 and the second electrode tab 201 are respectively disposed at two ends of the height direction H of the battery cell, and are respectively disposed at two sides of the width direction W of the battery cell.

[0045] In some other embodiments, Figure 5 As shown, the first electrode tab 101 and the second electrode tab 201 are respectively disposed at two ends of the height direction H of the battery cell, and are respectively disposed on the same side of the width direction W of the battery cell.

[0046] In some other embodiments, Figure 6 As shown, the first electrode tab 101 and the second electrode tab 201 are arranged at the same end in the height direction H of the battery cell, and are respectively arranged on both sides in the width direction W of the battery cell.

[0047] It is understandable that, due to the limited length of the first turning area, the first pole lug 101 and the second pole lug 201 only need to be arranged at different ends and sides of the battery cell, thereby avoiding the occurrence of a short circuit in the battery cell.

[0048] Battery

[0049] 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.

[0050] Electrical devices

[0051] 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.

[0052] Obviously, compared with the hollow pole piece structure of the prior art, the pole piece of the present application is a complete circle, which can increase the pole piece area and improve the energy density of the laminated battery. In addition, a pole ear placement area is preset on the cylindrical shell, and the side wall of the shell where the pole ear is required is locally thinned. This structural setting not only reduces the weight of the shell, but also improves the space utilization of the cylindrical shell, thereby improving the energy density of the battery.

[0053] 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, comprising a pole piece and a separator wound in sequence, characterized in that: The pole piece comprises a straight region (1), a first corner region and a second corner region (3) which are connected to each other, the first corner region and the second corner region (3) are respectively connected to the straight region (1), and the length of the first corner region is greater than the length of the second corner region (3); The first corner area is divided into a coating area (21) and an empty foil area (22), the coating area (21) and the empty foil area (22) are arranged alternately, and at least a portion of the empty foil area (22) extends out of the first corner area to serve as a pole lug.

2. The battery cell according to claim 1, characterized in that: The length L1 of the first corner area and the length L2 of the pole piece structure satisfy the following relationship: L1 / L2=a, a is an adjustment constant, 1 / 3<a<2 / 3.

3. The battery cell according to claim 2, characterized in that: When the number of layers of the battery core is ≤20, 1 / 3<a<1 / 2.

4. The battery cell according to claim 2, characterized in that: When the number of layers of the battery core is greater than 20, 1 / 2≤a<2 / 3.

5. The battery cell according to claim 1, characterized in that: The straight area (1) and the second corner area (3) have the same structure, both comprising a metal foil (4) and an active material coated on the metal foil (4).

6. The battery cell according to claim 1, characterized in that: The pole piece is divided into a first pole piece (100) and a second pole piece (200) of opposite polarities; the direction in which the empty foil area (22) in the first pole piece (100) extends is opposite to the direction in which the empty foil area (22) in the second pole piece (200) extends; and the first pole piece (100) and the second pole piece (200) are respectively extended with a first pole ear (101) and a second pole ear (201).

7. The battery cell according to claim 6, characterized in that: The first pole tab (101) and the second pole tab (201) are respectively arranged at two ends of the battery cell in a height direction (H), and are respectively arranged at two sides of the battery cell in a width direction (W).

8. The battery cell according to claim 6, characterized in that: The first pole tab (101) and the second pole tab (201) are respectively arranged at two ends of the battery cell in a height direction (H), and are respectively arranged on the same side of the battery cell in a width direction (W).

9. The battery cell according to claim 6, characterized in that: The first pole tab (101) and the second pole tab (201) are arranged at two ends of the battery cell in a height direction (H), and are respectively arranged at two sides of the battery cell in a width direction (W).

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

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