CN219303736U

CN219303736U - Battery and terminal equipment

Info

Publication number: CN219303736U
Application number: CN202223000856.8U
Authority: CN
Inventors: 胡心雨; 罗文辉
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Mobile Software Co Ltd
Priority date: 2022-11-10
Filing date: 2022-11-10
Publication date: 2023-07-04
Anticipated expiration: 2032-11-10

Abstract

The application discloses a battery and terminal equipment belongs to battery design technical field. The battery comprises a bare cell and a shell, wherein the bare cell comprises a first current collector, a second current collector, a diaphragm, a plurality of first active material layers and a plurality of second active material layers; the first active material layers are sequentially distributed on the surface of the first current collector along the length direction of the first current collector, a first gap is formed between every two adjacent first active material layers, the second active material layers are sequentially distributed on the surface of the second current collector along the length direction of the second current collector, and a second gap is formed between every two adjacent second active material layers; the first current collector, the diaphragm and the second current collector are stacked layer by layer and wound to form the bare cell, wherein the first gap and the second gap are located on two opposite sides of the bare cell. By adopting the scheme, smaller radians can be formed at two sides when the bare cell is wound, even planes are formed, and the bare cell and the shell are favorably attached to each other, so that the energy density of the battery is improved.

Description

Battery and terminal equipment

Technical Field

The application relates to the technical field of battery design, in particular to a battery and terminal equipment.

Background

Batteries have been widely used in portable electronic devices (e.g., mobile phones, tablet computers, notebook computers, etc.), electric vehicles, energy storage, etc. since they have been successfully commercialized.

Batteries are typically composed of a bare cell and a housing having a square receiving cavity within which the bare cell is located. Currently, a bare cell in a battery mostly adopts a winding structure, namely, a pole piece and a diaphragm in the bare cell are wound around a winding needle, and the winding needle is pulled out after winding is completed, so that the bare cell is formed. Wherein the pole piece is typically composed of an active material layer and a current collector, and the thickness of the active material layer is typically greater than the thickness of the current collector.

The both sides of the naked electric core that the coiling formed are arc, and this just makes naked electric core unable and square inner wall that holds the chamber laminating mutually, leads to the energy density of battery low.

Disclosure of Invention

The embodiment of the application provides a battery and terminal equipment, which can solve the problem of low battery energy density in the related technology. The technical proposal is as follows:

in a first aspect, the present application provides a battery comprising a bare cell including a first current collector, a second current collector, a separator, a plurality of first active material layers, and a plurality of second active material layers, and a housing;

the plurality of first active material layers are sequentially distributed on the surface of the first current collector along the length direction of the first current collector, first gaps are formed between the adjacent first active material layers, the plurality of second active material layers are sequentially distributed on the surface of the second current collector along the length direction of the second current collector, and second gaps are formed between the adjacent second active material layers;

the first current collector, the diaphragm and the second current collector are stacked layer by layer and are wound to form the bare cell, wherein the first gap and the second gap are located at two opposite sides of winding bending.

In one possible implementation, the inner surface of the housing conforms to the outer surface of the bare cell.

In one possible implementation, the first gap and the second gap are located on opposite sides of the bare cell in a width direction intersecting a direction in which the plurality of first active material layers and the plurality of second active material layers are stacked.

In one possible implementation manner, in the thickness direction of the bare cell, the width of the first active material layer close to the surface of the bare cell is greater than the width of the first active material layer far from the surface of the bare cell, the width of the second active material layer close to the surface of the bare cell is greater than the width of the second active material layer far from the surface of the bare cell, and the width direction of the first active material layer and the width direction of the second active material layer are both the same as the width direction of the bare cell.

In one possible implementation, the first active material layer is a negative electrode active material layer, the second active material layer is a positive electrode active material layer, and the width of the negative electrode active material layer is greater than the width of the positive electrode active material layer adjacent thereto.

In one possible implementation, the bare cell further includes: a plurality of third active material layers and a plurality of fourth active material layers;

the plurality of third active material layers are positioned on the surface of the first current collector and respectively positioned in the plurality of first gaps, and gaps are reserved between the third active material layers and the first active material layers adjacent to the third active material layers;

the fourth active material layers are positioned on the surface of the second current collector and respectively positioned in the second gaps, and gaps are reserved between the fourth active material layers and the second active material layers adjacent to the fourth active material layers.

In one possible implementation, the width of the gap on both sides of the third active material layer is the same and/or the width of the gap on both sides of the fourth active material layer is the same.

In one possible implementation manner, in the width direction of the bare cell, the width of the third active material layer close to the surface of the bare cell is greater than the width of the first active material layer far away from the surface of the bare cell, the width of the fourth active material layer close to the surface of the bare cell is greater than the width of the fourth active material layer far away from the surface of the bare cell, and the width direction of the third active material layer and the width direction of the fourth active material layer are both the same as the thickness direction of the bare cell.

In one possible implementation manner, the bare cell further includes a first tab and a second tab, wherein the first tab is connected with the first current collector, and the second tab is connected with the second current collector.

In a second aspect, the present application provides a terminal device comprising a battery as described in any one of the first aspect and its possible implementation forms.

The beneficial effects that technical scheme that this application embodiment provided brought are:

in the scheme provided by the embodiment of the application, the battery comprises a shell and a bare cell, wherein the bare cell comprises a first current collector, a second current collector, a diaphragm, a plurality of first active material layers and a plurality of second active material layers. The first active material layers are positioned on the surfaces of the first current collectors, first gaps are reserved between the adjacent first current collectors, the second active material layers are positioned on the surfaces of the second current collectors, and second gaps are reserved between the adjacent second current collectors. When the first current collector, the second current collector and the diaphragm are wound, the first gap and the second gap are positioned on two opposite sides of the wound bare cell. By adopting the scheme, as the first gap and the second gap are concentrated on two opposite sides of the bare cell, current collectors on two sides are thinner, smaller radian can be formed on two sides during winding, curvature is smaller, even a plane is formed, the bare cell is favorably attached to the inner wall of the shell, the vacant space in the shell is reduced, and the energy density of the battery is favorably increased.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural view of a battery according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a bare cell according to an embodiment of the present application;

fig. 3 is a schematic structural view of a current collector according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of a bare cell according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a current collector according to an embodiment of the present application.

Description of the drawings

1. A first current collector; 2. a second current collector; 3. a diaphragm; 4. a first active material; 5. a second active material; 6. a third active material; 7. a fourth active material; 8. a first tab; 9. a second lug;

l1, the length direction of the first current collector; l2, the length direction of the second current collector; w, the width direction of the bare cell; w1, width direction of the first active material layer; w2, the width direction of the second active material layer; t, the thickness direction of the bare cell; w3, the width direction of the third active material layer; w4, the width direction of the fourth active material layer;

10. a bare cell; 20. a housing.

Detailed Description

Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The terms "first," "second," "third," and the like in the description and in the claims, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Likewise, the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, is intended to mean that elements or items that are present in front of "comprising" or "comprising" are included in the word "comprising" or "comprising", and equivalents thereof, without excluding other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to denote relative positional relationships, which may also change accordingly when the absolute position of the object to be described changes.

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Batteries are typically composed of a bare cell and a housing having a square receiving cavity within which the bare cell is located. The bare cell adopts a winding structure, namely, a pole piece and a diaphragm in the bare cell are stacked and placed, then are wound around a winding needle, and the winding needle is pulled out after winding is completed, so that the bare cell is formed. In the related art, the electrode sheet is generally composed of an active material layer and a current collector, the thickness of the active material layer is generally greater than that of the current collector, and the tensile strength of the active material layer is also greater than that of the current collector.

In the winding process of the pole piece, as the active material layer has stronger tensile capacity, the two sides of the bare cell are in an arc structure generally, and the radian of the arc structure is larger, so that the two sides of the bare cell cannot be attached to the side wall of the square accommodating cavity, more vacant space exists between the two sides of the bare cell and the square accommodating cavity, and the energy density of the battery is low.

The embodiment of the application provides a battery, and this battery includes casing and naked electric core, and the arc structure of this naked electric core both sides compares the arc structure in the correlation technique and has less radian, is favorable to making naked electric core and the square inner wall that holds the chamber of casing laminate mutually, reduces the vacant space to be favorable to increasing the energy density of battery. Next, a battery provided in the embodiment of the present application will be described in detail.

Fig. 1 is a schematic structural view of a battery according to an embodiment of the present application. As shown in fig. 1, the battery includes a bare cell 10 and a case 20, the bare cell 10 is located in the case 20, and an outer surface of the bare cell 10 is attached to an inner surface of the case 20.

As an example, the case 20 may be a steel case having higher strength, and thus, the steel case is generally thinner in the case of satisfying specified rigidity requirements, so that the volume of the battery may be reduced, which is advantageous in improving the energy density of the battery.

Alternatively, the housing 20 may be an aluminum plastic film, and the structure of the aluminum plastic film is not described herein.

The bare cell 10 provided in the embodiment of the present application is described in detail below.

Fig. 2 is a schematic structural diagram of a bare cell according to an embodiment of the present application. As shown in fig. 2, the bare cell 10 includes: a first current collector 1, a second current collector 2, a separator 3, a plurality of first active material layers 4, and a plurality of second active material layers 5.

Fig. 3 is a schematic structural diagram of a current collector according to an embodiment of the present application. As shown in fig. 3, a plurality of first active material layers 4 are sequentially distributed on the surface of the first current collector 1 along the length direction L1 of the first current collector 1, and a first gap is formed between adjacent first active material layers 4; the plurality of second active material layers 5 are sequentially distributed on the surface of the second current collector 2 along the length direction L2 of the second current collector 2, and a second gap is formed between adjacent second active material layers 5.

Referring to fig. 2, the first current collector 1, the separator 3, the second current collector 2, and the separator 3 are stacked in this order, and then wound to form the bare cell 10, so that the first gap and the second gap are located at opposite sides of the winding bend, that is, the first gap and the second gap are located at opposite sides of the bare cell 10. As an example, when the battery is a block battery, the wound bare cell 10 may be approximately regarded as a square block structure.

In some examples, as shown in fig. 2, the first and second gaps are located on opposite sides of the bare cell 10 in the width direction W, and the plurality of first active material layers 4 and the plurality of second active material layers 5 are stacked in the thickness direction T of the bare cell 10, wherein the width direction W intersects (e.g., is perpendicular to, etc.) the thickness direction T in the above-described bare cell 10.

Alternatively, the first and second gaps may be located at opposite sides of the bare cell 10 in the thickness direction T, and the plurality of first active material layers 4 and the plurality of second active material layers 5 may be stacked in the width direction W of the bare cell 10.

By adopting the scheme, in the wound bare cell 10 (namely, the wound bare cell 10), the first gap and the second gap are concentrated at two opposite sides of the bare cell 10, and the current collector is thinner, and the tensile strength is smaller (namely, the current collector is easy to bend), so that smaller radian can be formed at two sides of the bare cell 10 during winding, the curvature is smaller, even a plane is formed, the bare cell 10 is favorably attached to the inner wall of the square accommodating cavity, and the vacant space in the square accommodating cavity is reduced, thereby being favorable for increasing the energy density of the battery.

As an example, as shown in fig. 2, in the thickness direction T of the bare cell 10, the width d1 of the first active material layer 4 near the surface of the bare cell 10 is larger than the width d2 of the first active material layer 4 far from the surface of the bare cell 10, the width d3 of the second active material layer 5 near the surface of the bare cell 10 is larger than the width d4 of the second active material layer 5 far from the surface of the bare cell 10, and the width direction W1 of the first active material layer 4 and the width direction W2 of the second active material layer 5 are both the same as the width direction W of the bare cell 10.

By sampling this, the space in the width direction W of the bare cell 10 can be utilized as much as possible, which is advantageous for further increasing the energy density of the battery.

In some examples, the first current collector 1 is a copper foil, the first active material layer 4 is a negative electrode active material layer, the second current collector 2 is an aluminum foil, and the second active material layer 5 is a positive electrode active material layer. Among the adjacent anode active material layers and cathode active material layers, the width of the anode active material layer is greater than or equal to the width of the cathode active material layer in the thickness direction T of the bare cell 10, as shown in fig. 2. By adopting the scheme, the positive electrode material can be ensured to fully participate in the reaction in the charge and discharge process, the working efficiency of the battery is improved, and the stability of the battery during working is ensured.

The negative electrode active material is prepared by mixing a negative electrode active material carbon material or non-carbon material with a binder and an additive. Examples of the negative electrode material include carbon negative electrode materials, alloy negative electrode materials, tin-based negative electrode materials, lithium-containing transition metal nitride negative electrode materials, nanoscale materials, and nanoscale negative electrode materials. The material of the anode active material is not limited in this application.

The positive electrode active material may be a sheet made of one or more of lithium cobaltate, lithium manganate, lithium iron phosphate and lithium nickel cobalt manganate (also referred to as ternary materials) which are common in the art, and the material of the positive electrode active material is not limited in this application.

Alternatively, the first current collector 1 is an aluminum foil, the first active material layer 4 is a positive electrode active material layer, the second current collector 2 is a copper foil, and the second active material layer 5 is a negative electrode active material layer.

The separator 3 may be a polyolefin film mainly composed of a polyethylene film or a polypropylene film, so as to ensure ion insulation of the separator 3, thereby mechanically isolating the first active material layer 4 from the second active material layer 5 and preventing short circuit. The separator 3 may also have a number of holes or pores to reduce the internal resistance of the bare cell 10 and to increase the ionic conductivity.

Fig. 4 is a schematic structural diagram of a bare cell provided in an embodiment of the present application, and fig. 5 is a schematic structural diagram of a current collector provided in an embodiment of the present application. As shown in fig. 4 and 5, the bare cell 10 may further include: a plurality of third active material layers 6 and a plurality of fourth active material layers 7. The plurality of third active material layers 6 are positioned on the surface of the first current collector 1 and respectively positioned in the first gaps formed by the plurality of first active material layers 1, and gaps are formed between the third active material layers 6 and the adjacent first active material layers 4; the fourth active material layers 7 are located on the surface of the second current collector 2 and are respectively located in the second gaps formed by the second active material layers 5, and gaps are formed between the fourth active material layers 7 and the adjacent second active material layers 5.

With this configuration, a gap is provided between the third active material layer 6 and the first active material layer 4, and a gap is also provided between the fourth active material layer 7 and the second active material layer 5, so that when winding is performed, a bare cell 10 having active material layers in four directions, i.e., up, down, left, and right, as shown in fig. 4 can be formed. Moreover, the four vertex angles shown in fig. 4 can form right angles or form an arc structure with an arc smaller than 90 degrees, so that the bare cell 10 can form a smaller arc in the four directions, and even form a plane, which is beneficial to attaching the side surface of the bare cell 10 to the inner wall of the square accommodating cavity, fully utilizes the space on the left side and the right side of the bare cell 10 in fig. 4, and is beneficial to improving the energy density of the battery.

In some examples, the width of the gap on both sides of the third active material layer 6 is the same, as is the width of the gap on both sides of the fourth active material layer 7. By adopting the scheme, the same deformation of the two sides of the third active material layer 6 and the two sides of the fourth active material layer 7 in the winding process can be ensured, and the shape of the wound bare cell 10 can be ensured.

As an example, as shown in fig. 4, in the width direction W of the bare cell 10, the width d5 of the third active material layer 6 near the surface of the bare cell 10 is larger than the width d5 of the first active material layer 4 far from the surface of the bare cell 10, the width d7 of the fourth active material layer 7 near the surface of the bare cell 10 is larger than the width d8 of the fourth active material layer 7 far from the surface of the bare cell 10, and the width direction W3 of the third active material layer 6 and the width direction W4 of the fourth active material layer 7 are both the same as the bare cell 10 in the thickness direction T.

The third active material layer 6 has the same material composition as the first active material layer 4, and the fourth active material layer 7 has the same material composition as the second active material layer 5. Among them, as shown in fig. 4, in the width direction W of the bare cell 10, the width of the anode active material layer is greater than or equal to the width of the cathode active material layer among the adjacent anode active material layer and cathode active material layer.

In some examples, the first current collector is a copper foil, the third active material layer 6 is a negative electrode active material layer, the second current collector 2 is an aluminum foil, and the fourth active material layer 7 is a positive electrode active material layer.

Alternatively, the first current collector 1 is an aluminum foil, the third active material layer 6 is a positive electrode active material layer, the second current collector 1 is a copper foil, and the fourth active material layer 7 is a negative electrode active material layer.

As an example, as shown in fig. 2, the bare cell 10 further includes a first tab 8 and a second tab 9, where the first tab 8 and the second tab 9 are located at the same end of the bare cell 10, and the first tab 8 is connected to the first current collector 1, the second tab 9 is connected to the second current collector 2, and the first tab 8 and the second tab 9 are used to connect to an external circuit. The first tab 8 and the first current collector 1 may be integrally formed, or may be fixedly connected by welding or the like; the second lug 9 and the second current collector 2 may be integrally formed, or may be fixedly connected by welding or the like.

Based on the same technical concept, the embodiment of the present application provides a terminal device, which includes any of the bare cells 10 provided in the embodiment of the present application, or includes any of the batteries provided in the embodiment of the present application. By adopting the scheme, in the terminal equipment, the bare cell 10 formed by winding is attached to the inner wall of the square accommodating cavity of the shell 20, so that the energy density of the battery is increased, and the cruising ability and the stability of the battery of the terminal equipment are improved.

The foregoing description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the utility model, since it is intended that all modifications, equivalents, improvements, etc. that fall within the spirit and scope of the utility model.

Claims

1. A battery, characterized in that the battery comprises a bare cell (10) and a housing (20), the bare cell (10) comprising a first current collector (1), a second current collector (2), a separator (3), a plurality of first active material layers (4) and a plurality of second active material layers (5);

the plurality of first active material layers (4) are sequentially distributed on the surface of the first current collector (1) along the length direction (L1) of the first current collector (1), first gaps are formed between the adjacent first active material layers (4), the plurality of second active material layers (5) are sequentially distributed on the surface of the second current collector (2) along the length direction (L2) of the second current collector (2), and second gaps are formed between the adjacent second active material layers (5);

the first current collector (1), the diaphragm (3) and the second current collector (2) are stacked layer by layer and are wound to form the bare cell (10), wherein the first gap and the second gap are positioned at two opposite sides of winding bending;

in the thickness direction (T) of the bare cell (10), the width of the first active material layer (4) close to the surface of the bare cell (10) is larger than the width of the first active material layer (4) far away from the surface of the bare cell (10), and the width of the second active material layer (5) close to the surface of the bare cell (10) is larger than the width of the second active material layer (5) far away from the surface of the bare cell (10).

2. The battery according to claim 1, wherein an inner surface of the case (20) is fitted to an outer surface of the bare cell (10).

3. The battery according to claim 1 or 2, characterized in that the first gap and the second gap are each located on opposite sides of the bare cell (10) in a width direction (W) intersecting a direction in which the plurality of first active material layers (4) and the plurality of second active material layers (5) are stacked.

4. A battery according to claim 3, characterized in that the width direction (W1) of the first active material layer (4) and the width direction (W2) of the second active material layer (5) are both the same as the width direction (W) of the bare cell (10).

5. The battery according to any one of claims 1, 2, 4, wherein the first active material layer (4) is a negative electrode active material layer, the second active material layer (5) is a positive electrode active material layer, and the width of the negative electrode active material layer is larger than the width of the positive electrode active material layer adjacent thereto.

6. The battery of any one of claims 1, 2, 4, wherein the bare cell further comprises: a plurality of third active material layers (6) and a plurality of fourth active material layers (7);

the plurality of third active material layers (6) are positioned on the surface of the first current collector (1) and are respectively positioned in the plurality of first gaps, and gaps are reserved between the third active material layers (6) and the first active material layers (4) adjacent to the third active material layers;

the fourth active material layers (7) are positioned on the surface of the second current collector (2) and are respectively positioned in the second gaps, and gaps are reserved between the fourth active material layers (7) and the second active material layers (5) adjacent to the fourth active material layers.

7. The battery according to claim 6, characterized in that the widths of the gaps on both sides of the third active material layer (6) are the same and/or the widths of the gaps on both sides of the fourth active material layer (7) are the same.

8. The battery according to claim 6, characterized in that in the width direction (W) of the bare cell (10), the width of the third active material layer (6) close to the surface of the bare cell (10) is larger than the width of the first active material layer (4) away from the surface of the bare cell (10), the width of the fourth active material layer (7) close to the surface of the bare cell (10) is larger than the width of the fourth active material layer (7) away from the surface of the bare cell (10), and the width direction (W3) of the third active material layer (6) and the width direction (W4) of the fourth active material layer (7) are both the same as the thickness direction (T) of the bare cell (10).

9. The battery according to any one of claims 1, 2, 4, 7, 8, wherein the bare cell (10) further comprises a first tab (8) and a second tab (9), the first tab (8) being connected to the first current collector (1), the second tab (9) being connected to the second current collector (2).

10. A terminal device, characterized in that it comprises a battery according to any of claims 1-9.