CN218919071U

CN218919071U - Battery cell

Info

Publication number: CN218919071U
Application number: CN202223095922.4U
Authority: CN
Inventors: 杨帆; 彭冲; 李俊义
Original assignee: Zhuhai Cosmx Battery Co Ltd
Current assignee: Zhuhai Cosmx Battery Co Ltd
Priority date: 2022-11-21
Filing date: 2022-11-21
Publication date: 2023-04-25
Anticipated expiration: 2032-11-21

Abstract

A battery comprises a battery core and an encapsulation shell for encapsulating the battery core, wherein a tab of the battery core is led out from one end or two ends of the encapsulation shell; the packaging shell comprises a metal shell with two open ends and a soft cladding arranged at the end part of the metal shell and used for closing the opening. The utility model adopts the composite packaging structure of the metal shell and the aluminum plastic soft coating, which not only utilizes the characteristics of high strength and good safety of the metal shell, but also can avoid the increase of the width caused by the package folding edge of the conventional aluminum plastic film by only using the soft coating package such as the aluminum plastic film at the two ends of the metal shell, thereby improving the energy density of the battery.

Description

Battery cell

Technical Field

The utility model belongs to the technical field of batteries, and particularly relates to a battery using a composite packaging shell.

Background

The lithium battery has the advantages of high energy density, small self-discharge, no memory effect and the like, and is widely applied in various fields. The lithium battery generally comprises a battery core and an encapsulation shell for encapsulating the battery core, the encapsulation shell of the lithium battery at present mainly comprises a hard shell and a soft shell, the hard shell is generally a metal shell such as a steel shell and an aluminum shell, and the soft shell is generally an aluminum plastic film. The metal shell has the advantages of high structural strength, deformation resistance and good safety performance, and is a main packaging form of the small battery. However, the metal case is heavy, which is disadvantageous in increasing the energy density of the battery. In addition, in order to ensure the safety performance, the metal shell is required to be provided with a pressure release valve and other parts, and the electrode lugs are required to be welded internally, so that the complexity of the preparation process is increased.

Disclosure of Invention

The utility model aims to provide a battery with a composite packaging shell, which can reduce the weight of the shell and simplify the preparation process.

A battery comprises a battery core and a packaging shell for packaging the battery core, wherein a tab of the battery core is led out from one end or two opposite ends of the packaging shell; the packaging shell comprises a metal shell with two open ends and a soft cladding arranged at the end part of the metal shell and used for closing the opening.

As described above, optionally, the end of the metal case is provided with a connection portion connected to the soft can, and the thickness of the connection portion is smaller than that of the metal case.

As described above, the thickness of the connecting portion is D, and the thickness of the metal case is D, and 0 < d.ltoreq.DX96%.

As described above, optionally, the end of the metal case is stepped, and a groove is formed at the end, where the groove is located at the periphery of the metal case or located at the inner wall of the metal case, and the soft can is matched with the groove and sleeved at the periphery of the connection part or embedded in the inner ring of the connection part.

As described above, optionally, the outer surface of the battery cell is provided with a foaming adhesive.

As described above, optionally, the thickness of the foam is not more than 1% of the thickness of the battery cell.

As described above, optionally, the end portion of the metal shell, from which the tab extends, is a tab-out end, the soft cladding for closing the tab-out end includes a first sub-shell and a second sub-shell, where the first sub-shell and the second sub-shell are disposed opposite to each other, and the tab-out end is wrapped, and the tab of the battery core extends out from the edge sealing portion of the first sub-shell and the second sub-shell.

The battery is characterized in that the electrode tab comprises a metal sheet connected with the electrode plate of the battery core and electrode tab glue arranged on the metal sheet, and the melting point of the electrode tab glue is 90-130 ℃.

The battery as described above, optionally, the junction of the metal case and the soft can is sealed by adhesive bonding or hot melt sealing; and/or the outer side of the joint of the soft cladding and the metal shell is stuck with a waterproof adhesive tape.

According to the technical scheme, the battery core is packaged by adopting the metal shell and soft-coated composite packaging structure, the end part of the metal shell is opened, and the tab outlet end of the metal shell is sealed by the soft-coated, so that the advantages of good safety, low thickness expansion and high energy density of the metal shell packaging structure are reserved, the end part of the metal shell is packaged by the soft-coated, the procedures of tab transfer welding, pressure relief valve setting and the like when the metal shell is packaged by a metal material can be omitted, the internal parts are reduced, the process is simplified, the battery structure is simple, and the production cost is low.

Drawings

In order to more clearly illustrate the embodiments of the present utility model, the following description will briefly explain the embodiments or the drawings required for the description of the prior art, it being obvious that the drawings in the following description are only some embodiments of the present utility model and that other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.

FIG. 1 is a schematic diagram of an exploded structure of an embodiment of the present utility model;

fig. 2 is a cross-sectional view of an embodiment of the present utility model.

The following describes the embodiments of the present utility model in further detail with reference to the drawings.

Detailed Description

In describing embodiments of the present utility model in detail, the drawings showing the structure of the device are not to scale locally for ease of illustration, and the schematic illustrations are merely examples, which should not limit the scope of the utility model. It should be noted that the drawings are in simplified form and are not to scale precisely, but rather are merely intended to facilitate and clearly illustrate the embodiments of the present utility model. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only to distinguish the description, and are not to be construed as indicating or implying relative importance or implying the number of technical features indicated; the terms "forward," "reverse," "bottom," "upper," "lower," and the like are used for convenience in describing and simplifying the description only, and do not denote or imply that the devices or elements being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the utility model.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, or can be communicated inside the two components, or can be connected wirelessly or in a wired way. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

As shown in fig. 1 and 2, the battery of the present embodiment includes a battery cell 1 and a package case 2 that encapsulates the battery cell 1, and the battery cell 1 is provided with a tab 3 protruding from one end thereof. The package 2 of the present embodiment includes a metal case 2-1 and a soft can. The battery of this embodiment is a single-ended tab structure, that is, the tab 3 extends only from one end of the package (battery), and in this embodiment, the end of the metal case 2-1 extending from the tab is defined as the top (first end), and the other end is the bottom (second end) of the metal case. The metal shell 2-1 has a cylindrical structure with two open ends, and the battery cell 1 is accommodated in the metal shell 2-1. The soft cover is used for closing the opening of the end part of the metal shell 2-1, and the soft cover of the embodiment comprises a first soft cover 2-2 and a second soft cover 2-3. The first soft cladding 2-2 and the second soft cladding 2-3 are respectively arranged at two ends of the metal shell 2-1, the first soft cladding 2-2 is arranged at the top (first end) of the metal shell 2-1 for closing the opening at the top of the metal shell 2-1, and the second soft cladding 2-3 is arranged at the bottom (second end) of the metal shell 2-2 for closing the opening at the bottom of the metal shell 2-1. The first soft cladding 2-2 and the second soft cladding 2-3 can be made of soft cladding materials such as aluminum plastic films and the like.

The metal shell 2-1 can be made of steel, aluminum, manganese, titanium, copper, magnesium, molybdenum or alloy materials thereof, and the metal material is used as a battery shell and has the characteristics of high hardness and good puncture resistance. The mass of the metal shell 2-1 is at least 90% of the total mass of the entire package 2. The inner side surface and/or the outer side surface of the metal shell 2-1 may be further subjected to a coating, plating, or the like to improve corrosion resistance, insulation, or the like. The metal shell 2-1 can be made by bending a metal sheet, and the joint of the metal sheet can be encapsulated by ultrasonic welding, laser welding, and the like. For small-sized battery cells, the metal shell 2-1 can also be manufactured by adopting a shell punching mode. When the metal shell is thicker or has a special shape, the metal shell can also be prepared by metal casting, cutting and the like. In order to avoid damage to the aluminum plastic film caused by burrs of the metal shell, polishing and cleaning are needed after the metal shell is manufactured. The edge sealing of the metal shell 2-1 can be subjected to secondary heat sealing connection after the battery is packaged, so that the battery cell is ensured not to leak liquid in the use process. Meanwhile, after the thermal lamination is finished, waterproof glue is stuck to the seal position, so that the thermal lamination area is prevented from being corroded by moisture. The metal shell 2-1 may not provide enough puncture strength when being too thin, the shell structure is easy to deform and the manufacturing process is difficult, while when the metal shell 2-1 is too thick, the large volume and the mass energy density are sacrificed, and according to the conclusion of practical experience, the thickness of the metal shell 2-1 can be 200-2000 mu m.

In order to maintain the flatness of the outer surface of the battery, as a preferred embodiment of the present utility model, connecting portions 2-1a connected to the soft can are provided at both ends of the metal case 2-1, and after the connecting portions 2-1a and the soft can are connected together by welding or the like, the thickness of the connecting portions 2-1a is smaller than that of the metal case 2-1, so that the end portion of the metal case 2-1 is stepped, a groove is formed at the end portion at the periphery of the metal case 2-1, and the first soft can 2-2 and the second soft can 2-3 are sleeved at the connecting portions 2-1 a. In this embodiment, the first soft cladding 2-2 and the second soft cladding 2-3 are both sleeved on the periphery of the connecting portion 2-1a, in other embodiments, a groove may be formed on the inner wall of the metal shell 2-1, and the soft cladding is disposed on the inner ring of the connecting portion 2-1a in an embedded manner. The thickness difference between the connecting portion 2-1a and the metal shell 2-1 can be equal to the thickness of the soft cladding, so that the soft cladding and the metal shell 2-1 can be kept flat at the connecting portion, the soft cladding cannot be excessively thick due to the introduction of the soft cladding, the soft cladding and the metal shell 2-1 can be kept flat at the connecting portion, and a certain protection effect can be achieved on the connecting portion when the battery falls, because if the thickness of the connecting portion is consistent with that of the metal shell, the thickness of the connecting portion of the soft cladding and the metal shell can be larger than that of other positions of the metal shell, and the positions with large thickness can be damaged more easily relative to other positions when the battery falls. Optionally, the thickness of the connecting part 2-1a is D, the thickness of the metal shell 2-1 is D, and D is more than 0 and less than or equal to D multiplied by 96%.

The joint of the metal shell 2-1 and the first soft cladding 2-2 and the second soft cladding 2-3 can be sealed in a cementing or hot melting connection mode, so that electrolyte is prevented from overflowing from the joint, or moisture is prevented from entering the battery from the joint, and the cycle performance and the safety performance of the battery are affected. When in use, the adhesive which has good adhesion capability to the polymer layer and the metal layer and is not easy to be dissolved by electrolyte is selected for bonding. When the two materials are connected through hot melting, the high polymer layer is compounded to the metal layer through high-temperature melting, so that the connection of the two materials is realized.

The battery cell 1 is accommodated in the metal case 2-1, and in order to facilitate the battery cell 1 being accommodated in the metal case 2-1, the outer dimension of the battery cell 1 should be smaller than the inner dimension of the metal case 2-1. Alternatively, in order to prevent the battery cell 1 from shaking in the metal case 2-1 and to ensure the reliability of the battery, a foaming adhesive 4 is provided on the outer surface of the battery cell 1, and the foaming adhesive 4 may be a commercially available hot melt foaming adhesive such as polyurethane foaming adhesive of sienna, silicone foaming adhesive of sienna, an Yitao-based flame retardant foaming adhesive, high temperature hot melt adhesive of germany, VA910 hot melt adhesive of korea music, 460 hot melt adhesive of dupont in the united states, WV1055 hot melt adhesive of thailand petrochemical industry, EA28150 hot melt adhesive of korean LG, or the like. The foaming adhesive 4 can be swelled at a certain temperature, so that the battery cell 1 is tightly connected with the inner wall of the metal shell 2-1 without shaking. The thickness of the foaming adhesive 4 is not more than 1% of the thickness of the battery cell 1.

The battery cell of the embodiment is of a structure with a single-ended tab, namely, the positive and negative tabs 3 extend out from the top of the battery cell 1. The electrode lug 3 is used for leading in/out current, the electrode lug 3 comprises a metal sheet and electrode lug glue, the metal sheet is connected with a pole piece of the battery cell, the metal sheet can be aluminum, steel, copper, nickel, titanium or alloy thereof, and the electrode lug glue can be made of polymer materials such as PP, PET and the like. The tab adhesive can be one or more layers and is used for being in hot melt connection with a polymer layer of the inner layer of the soft-package aluminum-plastic shell. The end part of the metal shell 2-1, which extends out of the tab, is a tab outlet end (top), and in order to facilitate the tab 3 to extend out, optionally, a first soft cladding 2-2, which encapsulates the tab outlet end of the metal shell 2-1, comprises a first sub-shell 2-2a and a second sub-shell 2-2b, the first sub-shell 2-2a and the second sub-shell 2-2b are oppositely arranged, the top of the metal shell 2-1 is wrapped, and the tab 3 extends out from the edge sealing part of the first sub-shell 2-2a and the second sub-shell 2-2 b. The first sub-case 2-2a and the second sub-case 2-2b are packaged and then subjected to conventional hemming processing. The tab 3 is encapsulated by an aluminum plastic film, and the tab is not required to be subjected to transfer welding operation according to the conventional preparation process of the steel shell battery.

According to the utility model, the soft cladding is used for sealing the two ends of the metal shell 2-1, and when the battery is in thermal runaway, overheated gas can be released from the connecting interface between the soft cladding and the metal shell or in a mode of film rupture and the like, so that the safety of the battery is ensured. Optionally, the melting point of the tab adhesive is lower than the melting point of the soft cladding heat seal, more specifically, the melting point of the tab adhesive is 90 ℃ -130 ℃ (which can contain an endpoint), therefore, when the battery is in thermal runaway, the interface adhesion between the tab adhesive and the aluminum plastic film is weakened when the temperature exceeds the melting point of the tab adhesive, after the battery cell produces gas, the gas is easier to break the top edge seal at the tab of the soft cladding, and the gas is flushed out from the connecting interface between the soft cladding and the metal shell to release, so that the safety of the battery can be better ensured, and the effect of the pressure release valve used with the metal shell is achieved.

The preparation process and structure of the battery of this example are further described below.

The battery package 2 of the present embodiment is composed of a metal case 2-1, a first soft can 2-2, and a second soft can 2-3. The metal shell 2-1 is formed by bending a thin steel sheet with the thickness of 300um, and the joint is sealed by ultrasonic welding. The metal shell 2-1 has a hollow rectangular parallelepiped shape, and its inner cavity has dimensions of 7×15×35mm. The thickness of the connecting portion 2-1a is 0.3mm. The metal shell 2-1 has a length of 35mm, the connection portion 2-1a connected to the first soft cover 2-2 has a length of 4mm, and the connection portion 2-1a connected to the second soft cover 2-3 has a length of 3mm.

The battery cell 1 is formed by winding a positive plate, a negative plate and a diaphragm, wherein the diaphragm is positioned between the positive plate and the negative plate and separates the positive plate from the negative plate. The positive electrode adopts lithium cobalt oxide as an active substance, and the negative electrode adopts graphite as an active substance. The battery cell 1 is hot-pressed after being wound, the pressure is 50MPa, the temperature is 95 ℃, the time is 3min, the size of the battery cell 1 after hot-pressing is 6.5X114.5X133 mm, and the hot-melt foaming adhesive 4 is arranged on the outer surface of the battery cell 1 after hot-pressing. The battery cell 1 can be placed into the metal shell 2-1 after hot pressing, the battery cell 1 can be attached to the inner wall of the metal shell 2-1 after free expansion, the metal shell 2-1 with the battery cell 1 is placed into a clamp with the temperature of 105 ℃ for hot pressing treatment, the foaming glue 4 is bonded after being heated in the metal shell 2-1, and the battery cell 1 and the metal shell 2-1 are connected and fixed together.

And punching the aluminum plastic film into a corresponding first soft cladding 2-2 and a corresponding second soft cladding 2-3 by adopting a die, wherein the thickness of the aluminum plastic film is 110um, the thickness of the PP layer is 40um, the thickness of the aluminum layer is 35um, and the thickness of the nylon layer is 35um. The punched second soft cladding 2-3 is sleeved at the bottom opening of the metal shell 2-1 in an interference fit mode, the second soft cladding 2-3 is connected with the connecting part 2-1a at the bottom of the metal shell 2-1 in an annular hot pressing mode, a waterproof adhesive tape is stuck on the outer side of the connecting part, and the thickness of the waterproof adhesive tape is 40 microns.

The first sub-shell 2-2a and the second sub-shell 2-2b are sleeved at the top opening of the metal shell 2-1, the first soft cladding 2-2 is connected with the connecting part 2-1a at the top of the metal shell 2-1 in an annular hot pressing mode, a waterproof adhesive tape is stuck on the outer side of the connecting part for a circle, and the thickness of the waterproof adhesive tape is 40um.

And injecting electrolyte from the top sealing area of the first soft cladding 2-2, and after the electrolyte injection is finished, carrying out hot-pressing compounding on the first soft cladding 2-2, wherein the tab glue of the tab 3 is also compounded at the edge sealing position, and the hot-pressing temperature is 115 ℃. And then performing processes such as formation, separation and the like to obtain the battery with the packaging structure of the semi-metal shell and the semi-aluminum plastic film package.

In the foregoing embodiment, the tab extends from one end of the battery to the outside of the metal case, and in other embodiments, the battery may have a structure in which the tab extends from two opposite ends of the package case (battery), that is, from two opposite ends of the metal case 2-1. When two ends of the soft shell are provided with the lugs, the second soft shell can also have the same structure as the first soft shell and consists of two opposite sub-shells.

The battery cell is arranged in the metal shell by adopting the composite packaging structure of the metal shell and the aluminum plastic soft coating, so that the characteristics of high strength and good safety of the metal shell can be utilized, meanwhile, the open end of the metal shell is packaged by adopting the soft coating shell such as the aluminum plastic film, the width increase caused by packaging folded edges when the conventional aluminum plastic film is used as a main packaging shell can be avoided, and the energy density of the battery is improved. In addition, compared with a hard shell battery, the lug end is encapsulated by the aluminum plastic film, the lug does not need to be welded in a rotating way, and meanwhile, a pressure release valve is not required to be arranged, so that the assembly process is simplified, when the battery core generates gas accidentally, gas can overflow from the edge sealing of the aluminum plastic film, and the safety performance of the battery is ensured. The battery has the advantages of high strength of the metal shell packaging structure and good safety, and has the advantages of simple aluminum plastic film packaging structure and low production cost.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present utility model is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery comprises a battery core and a packaging shell for packaging the battery core, wherein a tab of the battery core is led out from one end or two opposite ends of the packaging shell; the method is characterized in that:

the packaging shell comprises a metal shell with two open ends and a soft cladding arranged at the end part of the metal shell and used for closing the opening.

2. The battery of claim 1, wherein: the end part of the metal shell is provided with a connecting part connected with the soft cladding, and the thickness of the connecting part is smaller than that of the metal shell.

3. The battery of claim 2, wherein: the thickness of the connecting part is D, and the thickness of the metal shell is D, wherein D is more than 0 and less than or equal to D multiplied by 96 percent.

4. The battery of claim 2, wherein: the end part of the metal shell is in a step shape, a groove is formed at the end part, the groove is positioned at the periphery of the metal shell or positioned at the inner wall of the metal shell, the soft cladding is matched with the groove, and the soft cladding is sleeved at the periphery of the connecting part or embedded in the inner ring of the connecting part.

5. The battery of claim 1, wherein: the outer surface of the battery cell is provided with foaming glue.

6. The battery of claim 5, wherein: the thickness of the foaming adhesive is not more than 1% of the thickness of the battery cell.

7. The battery of claim 1, wherein: the end part of the metal shell, which extends out of the lug, is a lug outlet end, the soft cladding for closing the lug outlet end comprises a first sub-shell and a second sub-shell, the first sub-shell and the second sub-shell are oppositely arranged and wrap the lug outlet end, and the lug extends outwards from the edge sealing part of the first sub-shell and the second sub-shell.

8. The battery of claim 7, wherein: the electrode lug comprises a metal sheet connected with the electrode plate of the battery core and electrode lug glue arranged on the metal sheet, and the melting point of the electrode lug glue is lower than that of the soft cladding heat seal.

9. The battery of claim 8, wherein: the melting point of the tab adhesive is 90-130 ℃.

10. The battery of claim 1, wherein: the joint of the metal shell and the soft cladding is sealed by glue joint or hot melt; and/or the outer side of the joint of the soft cladding and the metal shell is stuck with a waterproof adhesive tape.