Lithium battery roll core and lithium battery

Abstract

The utility model discloses a lithium battery roll core and a lithium battery, the lithium battery roll core comprises a roll core body and at least one elastic piece, and the elastic piece is sleeved on the periphery of the roll core body. According to the technical scheme, at least one elastic piece is sleeved on the periphery of the roll core body, the elastic piece has elasticity, and when the roll core body expands, the elastic piece expands and deforms outwards along with the expansion of the roll core body, so that the stress generated by the expansion of the roll core body is released, the risk of breakage of the pole piece is reduced, and the service life of the pole piece is prolonged. The internal structure of the lithium battery is protected, and the service life of the lithium battery is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium ion batteries, in particular to a lithium battery coil and a lithium battery. Background Art

[0002] Lithium batteries are batteries that use lithium ions to move back and forth between positive and negative electrodes to store and release electrical energy. Lithium batteries have the advantages of high energy density, high power density, low self-discharge rate, and long life, and are widely used in various electronic devices. However, there are also some problems with lithium batteries during use, one of which is the expansion of the core (cell).

[0003] Core expansion refers to the phenomenon that during the charging and discharging process of lithium batteries, the core size increases and the shape deforms due to the volume change of the electrode material and the decomposition and gas production of the electrolyte. In order to prevent the core from expanding, the winding end of the current lithium battery core is generally fixed with adhesive tape or hot melt adhesive to maintain the stability of the core.

[0004] However, when the lithium battery core expands and deforms, the core cannot release internal stress because the adhesive tape restrains the core and prevents the expansion and deformation of the core, which causes the pole piece of the core to break. The breakage of the pole piece will damage the internal structure of the lithium battery, thereby reducing the battery life. Utility Model Content

[0005] The utility model provides a lithium battery winding core and a lithium battery, aiming to solve the technical problem that when the existing lithium battery winding core expands, the pole piece inside the winding core is easy to break.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0007] A lithium battery roll core, comprising:

[0008] core body;

[0009] At least one elastic member is sleeved on the outer circumference of the winding core body.

[0010] In some embodiments, the lithium battery roll core further includes a shell, the shell is configured with a cavity in which the roll core body can be placed, and the elastic member abuts against an inner wall of the cavity.

[0011] In some embodiments, a dimension of the elastic member in a height direction of the core body is less than or equal to a height of the core body.

[0012] In some embodiments, a plurality of the elastic members are provided, and the plurality of the elastic members are arranged at intervals along the height direction of the winding core body.

[0013] In some embodiments, the elastic member has a thickness of 0.05-0.5 mm.

[0014] In some embodiments, the elastic force of the elastic member satisfies the relationship: elastic force of the elastic member = elastic force coefficient of the elastic member * (initial area of ​​the core body * expansion coefficient of the core body). The initial area of ​​the core body refers to the bottom area of ​​the core body when it is not expanded, that is, the orthographic projection area of ​​the core body in the thickness direction when it is not expanded.

[0015] In some embodiments, the core body includes a positive electrode sheet, a separator, and a negative electrode sheet stacked in sequence, and the positive electrode sheet, the separator, and the negative electrode sheet are wound to form the core body.

[0016] In some embodiments, the winding end of the core body is a hollow foil area not coated with active material.

[0017] In some embodiments, the winding core body further includes two pole tabs, and the two pole tabs are respectively connected to the positive electrode sheet and the negative electrode sheet.

[0018] The embodiment of the utility model further provides a lithium battery, which includes the lithium battery core as described in the above embodiment.

[0019] In the technical solution of the utility model, at least one elastic member is sleeved on the outer periphery of the core body. The elastic member is elastic. When the core body expands, the elastic member expands and deforms outward along with the expansion of the core body, so that the stress generated by the expansion of the core body is released, thereby reducing the risk of electrode breakage, protecting the internal structure of the lithium battery, and increasing the life of the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a lithium battery roll core in one embodiment of the utility model;

[0021] Figure 2 A top view of a lithium battery roll core in one embodiment of the utility model;

[0022] Figure 3 for Figure 2 Sectional view at AA in the middle;

[0023] Figure 4 Schematic diagram of the structure of a lithium battery roll core in another embodiment of the present invention.

[0024] Description of Figure Numbers

[0025]

[0026]

[0027] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0028] In the present invention, the terms "disposed", "provided with", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] The orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or position relationship shown in the drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in this utility model can be understood according to specific circumstances.

[0032] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0033] The present invention provides a lithium battery roll core. Figure 1 , Figure 1 Schematic diagram of the structure of the battery roll core in this embodiment.

[0034] The lithium battery core of this embodiment includes:

[0035] Core body 1;

[0036] At least one elastic member 2 is sleeved on the outer circumference of the winding core body 1 .

[0037] In this embodiment, the core body 1 includes a positive electrode sheet, a separator and a negative electrode sheet, and the core body 1 is formed by stacking the positive electrode sheet, the separator and the negative electrode sheet in sequence and then winding them. Optionally, the positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence and then put into a winding machine for winding. The core body 1 of this embodiment can be a button-type core, a cylindrical core or a square core.

[0038] During the charge and discharge cycle of a lithium battery, the core body 1 will expand due to volume changes in the pole piece material, decomposition and gas production of the electrolyte, and other reasons. If the stress generated by the expansion is not released in time, it is easy to cause the pole piece of the core body 1 to break, thereby destroying the internal structure of the lithium battery. To this end, in this embodiment, at least one elastic member 2 is sleeved on the outer periphery of the core body 1. The material of the elastic member 2 can be a polymer material synthesized from copolymers such as polyethylene, styrene, and polypropylene. Optionally, the elastic member 2 is a ring with a length, that is, the elastic ring has a certain height in its axial direction. In one embodiment, the dimension of the elastic member 2 in the height direction of the core body 1 is less than or equal to the height of the core body 1. In this way, when the elastic member 2 is sleeved on the outer periphery of the core body 1, the elastic member 2 will not exceed the end face of the core body 1. The number of elastic members 2 is set to at least one. When a plurality of elastic members 2 are provided, such as Figure 4 As shown, Figure 4 A schematic structural diagram of a battery roll core in another embodiment is shown. In this embodiment, a plurality of elastic members 2 are arranged at intervals along the height direction of the roll core body 1 .

[0039] From the above, it can be seen that the embodiment of the utility model is provided with an elastic member 2 on the periphery of the core body 1. The elastic member 2 is elastic. When the core body 1 expands, the elastic member 2 expands and deforms outward along with the expansion of the core body 1, so that the stress generated by the expansion of the core body 1 is released, thereby reducing the risk of electrode breakage, protecting the internal structure of the lithium battery, and increasing the life of the lithium battery.

[0040] In some embodiments, please refer to Figure 1 The winding core body 1 further includes two tabs 11, and the two tabs 11 are connected to the positive electrode sheet and the negative electrode sheet respectively. Optionally, the two tabs 11 are connected to the positive electrode sheet and the negative electrode sheet respectively by ultrasonic welding. Optionally, the two tabs 11 can be welded to the outside of the winding core body 1 or welded to the inside of the winding core body 1.

[0041] In some embodiments, see Figure 2 and Figure 3 , Figure 2 : is a top view of the lithium battery roll core in this embodiment, Figure 3 for Figure 2 Cross-sectional view at AA in the middle.

[0042] The lithium battery roll core of the present embodiment further comprises a shell 3 , the shell 3 is configured with a cavity for placing the roll core body 1 , and the elastic member 2 abuts against the inner wall of the cavity.

[0043] In order to facilitate the assembly of the core into the shell, a certain gap is generally designed between the core and the shell. After the core and the shell are packaged, due to the gap between the core and the shell, relative displacement between the core and the shell is likely to occur during the subsequent testing process, thereby causing the tab 11 to break, increasing the risk of core failure.

[0044] To this end, an elastic member 2 is sleeved on the outer periphery of the core body 1 of the present embodiment. After the core body 1 is inserted into the cavity of the outer shell 3, the elastic member 2 abuts between the core body 1 and the inner wall of the cavity, eliminating the gap between the core body 1 and the inner wall of the outer shell 3. In this way, when the subsequent testing process is performed, relative displacement between the core body 1 and the outer shell 3 is avoided, thereby protecting the tab 11.

[0045] In some embodiments, the thickness of the elastic member 2 is 0.05-0.5 mm. Figure 1 and Figure 3 As shown, the dimensions of the elastic member 2 before and after being inserted into the shell 3 satisfy: 0≤D-D1≤0.3mm. Wherein, D represents the width dimension of the core body 1 and the elastic member 2 as a whole before being inserted into the shell, and D1 represents the width dimension of the core body 1 and the elastic member 2 as a whole after being inserted into the shell.

[0046] In some embodiments, the material of the elastic member 2 is selected according to the elastic force of the elastic member 2 and the expansion area of ​​the core body 1. Specifically, the elastic force of the elastic member 2 satisfies the relationship: elastic force of the elastic member = elastic force coefficient of the elastic member * (initial area of ​​the core body * expansion coefficient of the core body).

[0047] In some embodiments, the winding end of the core body 1 is an empty foil area without active material coating, such as copper foil or aluminum foil. In this embodiment, the core is finished with copper foil or aluminum foil after winding to keep the shape of the core stable.

[0048] The embodiment of the utility model further provides a lithium battery, which includes the lithium battery core as described in the above embodiment.

[0049] The specific structure of the lithium battery roll core refers to the above-mentioned embodiments. Since the lithium battery adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the technical effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0050] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A lithium battery core, characterized in that: include: core body; A plurality of elastic members are sleeved on the outer circumference of the winding core body, and the plurality of elastic members are arranged at intervals along the height direction of the winding core body.

2. The lithium battery roll core according to claim 1, characterized in that: It also includes a shell, which is configured with a cavity in which the winding core body can be placed, and the elastic member abuts against an inner wall of the cavity.

3. The lithium battery roll core according to claim 1, characterized in that: The dimension of the elastic member in the height direction of the core body is less than or equal to the height of the core body.

4. The lithium battery roll core according to claim 1, characterized in that: The thickness of the elastic member is 0.05-0.5 mm.

5. The lithium battery roll core according to claim 1, characterized in that: The elastic force of the elastic member satisfies the relationship: elastic force of the elastic member=elastic force coefficient of the elastic member*(initial area of ​​the winding core body*expansion coefficient of the winding core body).

6. The lithium battery roll core according to claim 1, characterized in that: The winding core body comprises a positive electrode sheet, a separator and a negative electrode sheet stacked in sequence, and the positive electrode sheet, the separator and the negative electrode sheet are wound to form the winding core body.

7. The lithium battery roll core according to claim 6, characterized in that: The winding end of the winding core body is an empty foil area which is not coated with active material.

8. The lithium battery roll core according to claim 6, characterized in that: The winding core body further includes two pole tabs, and the two pole tabs are respectively connected to the positive electrode sheet and the negative electrode sheet.

9. A lithium battery, characterized in that: Comprising a lithium battery roll core as described in any one of claims 1 to 8.

Images