WO2022141260A1

WO2022141260A1 - Composite foil, battery packaging shell, and battery

Info

Publication number: WO2022141260A1
Application number: PCT/CN2020/141670
Authority: WO
Inventors: 夏恒涛
Original assignee: 宁德新能源科技有限公司
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2022-07-07
Also published as: CN113728492A

Abstract

Disclosed in the present application are a composite foil, a battery packaging shell, and a battery, capable of reducing the probability of damage to the battery. The composite foil comprises: a substrate; and a first foil layer and a second foil layer respectively distributed in different areas of a first surface of the substrate, the hardness of the first foil layer being greater than the hardness of the second foil layer, and the difference of the hardness values of the first foil layer and the second foil layer being greater than or equal to HB300.

Description

Composite foils, battery packs, and batteries

technical field

The present application relates to the field of battery energy, in particular to a composite foil, a battery packaging case and a battery.

Background technique

Traditional batteries are very prone to damage. Once the battery is damaged, it will not only cause economic damage, but also the reaction solution inside the battery is likely to leak out, pollute the environment, and even cause a short circuit at the sharp corners, causing the battery to smoke, catch fire or even explode. Danger.

There is an urgent need to propose a new battery packaging foil to reduce the probability of battery breakage.

SUMMARY OF THE INVENTION

In view of this, the present application provides a composite foil, a battery packaging case and a battery, which can reduce the probability of damage to the battery.

A composite foil material provided by the present application includes: a base material; a first foil layer and a second foil layer, which are respectively distributed in different regions of the first surface of the base material, and the hardness of the first foil layer is greater than that of the first foil layer. hardness of the second foil layer, and the difference in hardness between the first foil layer and the second foil layer is greater than or equal to HB300.

By setting the first foil layer and the second foil layer with different hardness, the composite foil has different strengths in different regions, and the specific materials of the first foil layer and the second foil layer can be set as required, such as The second foil layer is made of aluminum film, and at this time, the hardness of the first foil layer is at least greater than that of the aluminum film.

A first material layer is disposed between the first foil layer and the second foil layer, and the first material layer includes at least one of a polypropylene layer, a polyethylene layer and a nylon layer. The polypropylene layer, the polyethylene layer and the nylon layer all have good absorption properties, which can absorb vibration, the stress between the first foil layer and the second foil layer, etc., play a buffering role, and further optimize the properties of composite foils.

The first foil layer includes at least one of a stainless steel layer, a titanium alloy layer, and an aluminum alloy layer, the second foil layer includes an aluminum layer, and the base material includes a polypropylene layer. Using these material layers as the first foil layer and the second foil layer can effectively improve the hardness requirements of the composite foil, and the composite foil can still be deformed, which is convenient for wrapping on the surface of the object, which can effectively improve the hardness of the composite foil. protection of objects.

The thickness of the stainless steel layer is in the range of 0.04mm-0.150mm, and the thickness of the aluminum layer is in the range of 0.05mm-0.180mm. In this thickness range, the composite foil can play a better protective effect. In fact, the thickness distribution of the stainless steel layer and the aluminum layer can also be set as required

The composite foil further includes a second material layer located at least between the first foil layer and the substrate, and at least between the second foil layer and the substrate. time, and the viscosity of the second material layer is greater than the first preset value. Using the second material layer, the first foil layer and the second foil layer can be well adhered to the surface of the substrate, preventing the first foil layer and the second foil layer from being opposed to each other. Displacement occurs on the substrate.

In addition, the second material layer may only be located between the first foil layer and the substrate, and between the second foil layer and the substrate, on the basis of satisfying the bonding requirements, also The usage amount of the second material layer is reduced, and the function of energy saving and environmental protection is played.

The material of the second material layer includes at least one of polyacrylated material and glue. In fact, when the material of the substrate is the polypropylene material, there is no need to additionally configure the polyacrylated material, but the substrate can be directly acidified to play the role of bonding and simplify the preparation. Processes required for the composite foil.

Since the hardness of the second foil layer is lower than that of the second foil layer, additional protection of the second foil layer by the third material layer is required. The third material layer is formed on the first surface of the second foil layer, and the material of the third material layer includes at least one of nylon material or resin material. In fact, other resistant materials, such as polyethylene materials, can also be selected as required.

The thickness of the first foil layer is greater than the thickness of the second foil layer, and the first surface of the third material layer is flush with the first surface of the first foil layer, so the first surface of the composite foil is One surface is flat, which is convenient for storage and stacking of the composite foil.

A plurality of first foil layers and a plurality of second foil layers are distributed on the first surface of the base material, so as to meet the requirement of separately protecting different regions of the object when the composite foil is wrapped on the surface of the object.

A battery packaging case provided by the present application includes: a case, which is prepared from the composite foil, and the second surface of the base material of the composite foil faces the inner side of the case.

A first material layer is disposed between the first foil layer and the second foil layer, and the first material layer includes at least one of a polypropylene layer, a polyethylene layer and a nylon layer.

The area where the first foil layer of the composite foil is located corresponds to at least the top surface and the bottom surface of the casing. When the battery cell is assembled into the battery packaging casing, the first foil layer can effectively protect the battery pack. The top and bottom surfaces of the core. The area where the second foil layer of the composite foil is located corresponds to at least the side wall of the case, which effectively reduces the weight of the battery packaging case and meets the requirements of bending and forging deformation between various surfaces of the battery packaging case.

A battery provided by the present application includes the battery packaging case and a battery cell, and the battery cell is arranged in the case.

The first surface of the battery core is opposite to a preset area on the inner surface of the casing, and the preset area is coated with a coating, the material of the coating includes hot melt adhesive, and the viscosity of the coating is greater than second preset value. By setting the preset area, the battery can have no slippage relative to the preset area on the inner surface of the casing, thereby effectively ensuring the first surface of the battery cell.

The preset area includes at least a first part opposite to the area where the first foil layer is located, and the area of the first part is greater than or equal to the area of the first surface of the cell, therefore, the first foil layer is located The area can completely protect the first surface of the battery cell and play a better protective role.

The composite foil, battery packaging case and battery of the present application use the first foil layer and the second foil layer with a hardness difference of at least HB300. Therefore, the minimum hardness of the first foil layer is HB300, which can effectively improve the composite foil and battery packaging. The hardness of the shell and the battery reduces the probability of damage to the battery, and because the hardness of the second foil layer is low, it can also simplify the processing of the composite foil, which is impacted and squeezed to the point of being deformed. Processing difficulty.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained from these drawings without creative effort.

FIG. 1 is a schematic structural diagram of the composite foil of the first embodiment;

FIG. 2 is a schematic structural diagram of the composite foil of the second embodiment;

FIG. 3 is a schematic structural diagram of the composite foil of the third embodiment;

4 is a schematic structural diagram of the battery packaging case in an embodiment;

FIG. 5 is a schematic structural diagram of the battery in one embodiment.

Detailed ways

The inventors have found that the reason why the battery is prone to damage in the prior art is that the battery usually uses an aluminum film as the packaging shell.

In addition, because the battery will generate heat and gas during use, and the aluminum film has low hardness and is prone to deformation, the battery is prone to bulge during use, causing short-circuiting at sharp corners, causing the battery to emit smoke, Fire or even explosion.

The inventor's research also found that if a single material with higher hardness such as a steel foil is used to prepare the battery packaging case, although the disadvantage of the lower hardness of the aluminum film can be overcome, due to the higher hardness of these materials, the production The battery packaging case has high processing difficulty, low output and high cost, and is very unsuitable for large-scale industrial production.

In order to overcome the above problems, the inventor proposes a composite foil, a battery packaging case and a battery. In order to make the objectives, technical solutions and advantages of the present application clearer, the composite foil, the battery packaging case and the battery will be further described below with reference to the embodiments and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of them. Based on the embodiments of the present application, the following embodiments and their technical features can be combined with each other without conflict.

Please refer to FIG. 1 , which is a schematic diagram of the structure of the composite foil in the first embodiment.

In the first embodiment, the composite foil 100 includes: a base material 101; The hardness of the first foil layer 102 is greater than the hardness of the second foil layer 103 , and the difference in hardness between the first foil layer 102 and the second foil layer 103 is greater than or equal to HB300.

Since the difference in hardness between the first foil layer 102 and the second foil layer 103 is greater than or equal to HB300, the hardness of the first foil layer 102 is greater than or equal to HB300. The range is HB50 to HB60), and there is a big difference in hardness. Therefore, when using the composite foil 100 to prepare the battery packaging case 400, it can play a stronger protective role and reduce the probability of battery damage.

Moreover, since the second foil layer 103 is also provided, the hardness is relatively small, so the difficulty of processing the composite foil 100 can be reduced by planning the specific distribution area of the second foil layer 103 .

In this first embodiment, the substrate 101 comprises a polypropylene layer. Polypropylene material has the following characteristics: colorless, odorless, non-toxic, and thermoplastic, and its chemical resistance, heat resistance, abrasion resistance and electrical insulation properties are good. Using the polypropylene material as the base material 101 can meet the deformation requirements of the composite foil 100 during application.

In the first embodiment, the first foil layer 102 is a stainless steel layer, and the stainless steel layer has high hardness, which can prevent the battery packaging case 400 from being damaged when the battery is dropped, and also has the characteristics of corrosion resistance, which can prolong the battery life. battery life.

The thickness of the stainless steel layer ranges from 0.04mm to 0.150mm. At this time, the distribution area of the first foil layer 102 of the battery packaging case 400 prepared from the composite foil 100 has a better protective effect on the battery cells 501, and due to the moderate thickness, it will not cause the weight of the battery packaging case 400. is too big.

In fact, other materials with higher hardness can also be selected as the first foil layer 102 as required, such as a stainless steel layer, a titanium alloy layer, an aluminum alloy layer, and the like. In some other embodiments, the first foil layer 102 includes any one of a stainless steel layer, a titanium alloy layer, and an aluminum alloy layer, or several of these material layers are perpendicular to the substrate 101100 . Sequential stacking in the direction of the first surface 1011 .

The second foil layer 103 includes an aluminum layer, and the aluminum layer has a certain degree of softness and is suitable for the situation that needs to be deformed. In addition, the aluminum layer has the characteristics of low density, high plasticity, good ductility, corrosion resistance, easy recycling, easy surface treatment, etc. When the composite foil 100 is used, the aluminum layer can follow the substrate 101 to deform, It can be extended, so that it can be easily wrapped on the surface of objects such as the battery core 501, and has a certain protective effect on these objects.

The thickness of the aluminum layer is in the range of 0.05mm-0.180mm. At this time, the battery packaging case 400 prepared by the composite foil 100 can also play a better role in protecting the battery core 501 in the distribution area of the second foil layer 103 . In fact, the thickness distribution of the stainless steel layer and the aluminum layer can also be set as required.

The hardness of the aluminum layer is in the range of HB62 to HB150, and the hardness of the stainless steel layer is in the range of HB600 to HB660. The hardness difference between the foil layers 103 meets the hardness requirements of the composite foil 100 for the first foil layer 102 and the second foil layer 103 .

The mixed use of the aluminum layer and the stainless steel layer helps to control the manufacturing price of the composite foil 100 , and reduces the processing difficulty of the composite foil 100 while ensuring the strength of the composite foil 100 .

The first foil layer 102 and the second foil layer 103 are distributed in different regions of the first surface 1011 of the substrate 101 , therefore, the specific details of the first foil layer 102 and the second foil layer 103 can be set as required Distribution area and distribution quantity, when the composite foil 100 is used to wrap objects of different shapes, the required composite foil 100 can be selected according to the shape characteristics of the objects.

For example, when the composite foil 100 is used to protect a triangular-conical object, since the four vertices of the triangular-conical object are very easily impacted and damaged when the triangular-conical object falls on the ground, the triangular-cone The top corners of shaped objects require additional focus protection. When the composite foil 100 is selected to be wrapped on the surface of the triangular pyramid object, the first foil layer 102 is distributed in at least four regions of the composite foil 100, and there are four distributions of the first foil layer The area of 102 covers the four top corners of the triangular pyramid object, so as to play a better protective effect.

In the first embodiment, a first material layer 104 is disposed between the first foil layer 102 and the second foil layer 103, and the first material layer 104 includes a polypropylene layer, a polyethylene layer and a nylon layer At least one of these material layers has better absorption performance, can absorb the energy generated by the impact, has corresponding absorption to the impact energy and vibration, and can absorb the first foil layer 102 and the second foil layer 103. The stress between them can also play a certain buffering role, which can further optimize the performance of the composite foil 100 .

In fact, the first foil layer 102 and the second foil layer 103 can also be directly adjacent to each other, which can reduce the structural complexity of the composite foil 100 , here can refer to FIG. 2 , which is described in the second embodiment. A schematic diagram of the structure of the composite foil 100 is shown.

In some other embodiments, although there is a gap between the first foil layer 102 and the second foil layer 103, the first material layer 104 is not filled. Please refer to FIG. 3, which is the third embodiment. Schematic diagram of the structure of the composite foil 100 described in . This can reduce the structural complexity of the composite foil 100 and at the same time reduce the self-weight of the composite foil 100 , so as to broaden the scope of application scenarios of the composite foil 100 .

The composite foil 100 further includes: a second material layer 106 for assembling the first foil layer 102 and the second foil layer 103 to the surface of the substrate 101, and the viscosity of the second material layer 106 greater than the first preset value. Using the second material layer 106, the first foil layer 102 and the second foil layer 103 can be well adhered to the surface of the substrate 101, preventing the first foil layer 102 and the The second foil layer 103 is displaced relative to the substrate 101 .

In the first embodiment shown in FIG. 1 , the second material layer 106 is located on the first surface 1011 of the substrate 101 to adhere the first foil layer 102 and the second foil layer 103 . In the first embodiment, a first material layer 104 is formed between the first foil layer 102 and the second foil layer 103 , and the first material layer 104 is also adhered to by the second material layer 106 the first surface of the substrate 101 .

Actually, the second material layer 106 can also be provided as required. When there is a gap between the first foil layer 102 and the second foil layer 103, the second material layer 106 is at least located between the first foil layer 102 and the substrate 101, and at least located between the first foil layer 102 and the substrate 101. Between the second foil layer 103 and the substrate 101

In the third embodiment shown in FIG. 3 , the second material layer 106 is only located between the first foil layer 102 and the substrate 101 , and the second foil layer 103 and the substrate 101 , the bonding requirements are met, and the usage amount of the second material layer 106 is also reduced, which has the advantages of reducing the manufacturing cost, saving energy and protecting the environment.

The material of the second material layer 106 includes at least one of polyacrylated material and glue. When the material of the base material 101 is the polypropylene material, the base material 101 can be directly acidified to obtain a polyacrylated material without additional configuration of the polyacrylated material, which can effectively simplify the preparation Processes required for the composite foil 100 .

In the first embodiment shown in FIG. 1 , the second material layer 106 is formed of a polyacrylated material, and the thickness of the second material layer 106 formed of the polyacrylated material ranges from 10um to 30um.

In some embodiments, the second material layer 106 is formed of glue having a weight of 2 to 3 g/m ² .

Since the hardness of the second foil layer 103 is smaller than the hardness of the second foil layer 103 , in this embodiment, a third material layer 105 is further provided to protect the second foil layer 103 . The third material layer 105 is formed on the first surface of the second foil layer 103 , and the first surface of the second foil layer 103 is opposite to the bonding surface of the second foil layer 103 and the substrate 101 . The third material layer 105 has high resistance, including corrosion resistance, abrasion resistance, etc., to prevent the second foil layer 103 from being worn when the composite foil 100 is used.

In some embodiments, the material of the third material layer 105 includes at least one of nylon material or resin material. In fact, other resistant materials, such as polyethylene materials, can also be selected as required.

In some other embodiments, the third material layer 105 may also cover the first surface of the first foil layer 102 , so as to simultaneously cover the first foil layer 102 and the second foil layer 103 Protective effects.

The third material layer 105 is bonded to the surfaces of the first foil layer 102 and the second foil layer 103 by glue or the like.

In this embodiment, the thickness of the first foil layer 102 is greater than the thickness of the second foil layer 103. In this case, the distribution area of the first foil layer 102 of the composite foil layer can provide sufficient protection strength, and at the same time It is also possible to reduce the amount of materials used for the preparation of the second foil layer 103 .

In order to make the first surface of the composite foil 100 flat, the first surface of the third material layer 105 is flush with the first surface of the first foil layer 102, the first foil layer 102 and the second The first surface of the first material layer 104 between the foil layers 103 is also flush with the first surface of the first foil layer 102 . The first surface of the composite foil 100 is flat, which facilitates the storage and stacking of the composite foil 100 .

In fact, referring to FIGS. 2 and 3 , the thickness of the first foil layer 102 can also be equal to the thickness of the second foil layer 103 , and the thickness of the first foil layer 102 is not greater than that of the second foil layer 103 thickness is limited.

When the thickness of the first foil layer 102 is equal to the thickness of the second foil layer 103, when the third material layer 105 is to be formed, the third material layer 105 may be covered to the first foil layer at the same time. The surfaces of the first foil layer 102 and the second foil layer 103 not only keep the first surface of the composite foil 100 flat, but also achieve surface protection for both the first foil layer 102 and the second foil layer 103 .

The embodiment of the present application also includes a battery packaging case 400 .

Please refer to FIG. 4 , which is a schematic structural diagram of the battery packaging case 400 in an embodiment. In this embodiment, the structure of the composite foil 100 used is shown in FIG. 2 .

In the embodiment shown in FIG. 4 , the battery packaging case 400 includes: a case 401 made of the composite foil 100 (refer to FIG. 2 ), and the base material 101 of the composite foil 100 is The second surface faces the inside of the casing 401 , and the second surface of the base material 101 of the composite foil 100 is opposite to the first surface 1011 (refer to FIG. 2 ) of the base material 101 of the composite foil 100 .

A first material layer 104 is disposed between the first foil layer 102 (refer to FIG. 2 ) and the second foil layer 103 (refer to FIG. 2 ), and the first material layer 104 includes a polypropylene layer, a polyethylene layer and at least one of the nylon layers, used as a buffer, which can not only buffer the external impact, but also buffer the stress between the first foil layer 102 and the second foil layer 103, so as to further optimize Properties of the composite foil 100 .

The area where the first foil layer 102 of the composite foil 100 is located corresponds to at least the top surface and the bottom surface of the casing 401 . This is because the bottom and top of the battery cell 501 are usually provided with structures such as electrodes. Once these structures are damaged or damaged, the battery will be directly damaged. The requirements for the protection strength of the packaging shell 400 are higher. When the battery cells 501 are assembled into the battery packaging case 400 , the first foil layer 102 can effectively protect the bottom and top of the battery cells 501 .

In order to reduce the overall quality of the battery packaging case 400, and to meet the requirements of impact forging and bending deformation when the composite foil 100 is formed into the battery packaging case 400, the composite foil 100 is formed into the battery packaging case 400. When the casing 401 is used, at least five bendings are required, so the area where the second foil layer 103 of the composite foil 100 is located corresponds to the side wall of the casing 401 , and the hardness of the second foil layer 103 is less than The hardness of the first foil layer 102 can meet the requirements of being impacted and deformed, thereby reducing the difficulty of preparing the battery packaging case 400 .

In the embodiment shown in FIG. 4 , since the edge regions of the top and bottom surfaces of the casing 401 need to receive impact and bend to form the casing 401 , the second foil layer 103 of the composite foil 100 It is also distributed to the edge regions of the top surface and the bottom surface of the casing 401 correspondingly, so as to meet the requirements of the composite foil 100 being impacted and deformed.

The utility model of the present application also includes a battery.

Please refer to FIG. 5 , which is a schematic diagram of the structure of the battery in one embodiment. In this embodiment, the structure of the battery packaging case 400 used is shown in FIG. 4 .

In the embodiment shown in FIG. 5 , the battery 500 includes the battery packaging case 400 (refer to FIG. 4 ) and a battery cell 501 , and the battery cell 501 is disposed in the casing 401 .

The battery cell 501 refers to an electrochemical cell 501 containing a positive electrode and a negative electrode, which is a power storage part in the battery, and can be directly used as a battery after being equipped with a protection circuit and a battery packaging case 400 .

The first surface of the battery cell 501 is opposite to a predetermined area 502 on the inner surface of the housing 401 . When the battery cell 501 is assembled into the housing 401 , the first surface and the Let the regions 502 be in contact. The preset area 502 is coated with a coating, the material of the coating includes hot melt adhesive, the viscosity of the coating is greater than the second preset value, and the battery core 501 can be adhered to the preset The surface of the area 502 prevents the cell 501 from slipping compared to the preset area 502 , thereby preventing the cell 501 from slipping and colliding with the casing 401 in the casing 401 , causing damage to the battery cell 501 and the casing 401 .

The preset area 502 at least includes a first part opposite to the area where the first foil layer 102 is located, the first part is not shown in FIG. 5 , and the area of the first part is greater than or equal to the cell 501 area of the first surface.

When the battery cell 501 is assembled into the casing 401 , the first surface of the battery cell 501 is completely in contact with the first part of the predetermined area 502 , and the first part is in the first part of the battery cell 501 . The projection on the first surface covers the first surface of the battery cell 501. Therefore, the first surface of the battery core 501 can be completely protected by the first foil layer 102, so as to obtain better protection. The possibility of damage to the battery is reduced.

The composite foil 100 , the battery packaging case 400 and the battery of the present application use the first foil layer 102 and the second foil layer 103 with different hardnesses, and the specific details of the first foil layer 102 and the second foil layer 103 can be configured as required. The hardness is improved, the hardness of the battery packaging case 400 is increased, the strength of the battery packaging case 400 is reduced, and the probability of damage to the battery is reduced, which is simple and convenient.

The above descriptions are only the embodiments of the present application, which are not intended to limit the scope of the patent of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, such as the interaction of technical features between the embodiments Combination, or direct or indirect application in other related technical fields, are equally included in the scope of patent protection of this application.

Claims

A composite foil, characterized in that, comprising:

substrate; and,

The first foil layer and the second foil layer are respectively distributed in different regions of the first surface of the substrate, the hardness of the first foil layer is greater than that of the second foil layer, and the first foil layer is The difference in hardness with the second foil layer is greater than or equal to HB300.
The composite foil according to claim 1, wherein a first material layer is disposed between the first foil layer and the second foil layer, and the first material layer comprises a polypropylene layer, a polyethylene layer and at least one of the nylon layers.
The composite foil material according to claim 1, wherein the first foil layer includes at least one of a stainless steel layer, a titanium alloy layer, and an aluminum alloy layer, the second foil layer includes an aluminum layer, and the The substrate includes a polypropylene layer.
The composite foil material according to claim 3, wherein the thickness of the stainless steel layer is in the range of 0.04mm-0.150mm, and the thickness of the aluminum layer is in the range of 0.05mm-0.180mm.
The composite foil of claim 1, further comprising: a second material layer located at least between the first foil layer and the substrate, and at least between the first foil layer and the substrate Between the second foil layer and the substrate, the viscosity of the second material layer is greater than the first preset value.
The composite foil material according to claim 5, wherein the material of the second material layer comprises at least one of polyacrylated material and glue.
The composite foil material according to claim 1, wherein a third material layer is formed on the first surface of the second foil layer, and the material of the third material layer comprises at least one of nylon material or resin material kind.
The composite foil according to claim 7, wherein a plurality of first foil layers and a plurality of second foil layers are distributed on the first surface of the base material, and the composite foil according to claim 7, It is characterized in that the thickness of the first foil layer is greater than the thickness of the second foil layer, and the first surface of the third material layer is flush with the first surface of the first foil layer.
The composite foil according to claim 1, wherein a plurality of first foil layers and a plurality of second foil layers are distributed in different regions of the first surface of the base material.
A battery packaging case, comprising:

A casing, prepared from the composite foil of claim 1, with the second surface of the substrate of the composite foil facing the inside of the casing.
The battery packaging case according to claim 10, wherein a first material layer is disposed between the first foil layer and the second foil layer, and the first material layer comprises a polypropylene layer, a polyethylene layer and at least one of the nylon layers.
The battery packaging case according to claim 10, wherein the area where the first foil layer of the composite foil material is located corresponds to at least the top surface and the bottom surface of the case; the second foil layer of the composite foil material The area at least corresponds to the side wall of the casing.
A battery, characterized in that, comprising:

The battery packaging case of claim 10;

The battery core is arranged in the casing.
The battery according to claim 13, wherein the first surface of the battery core is opposite to a predetermined area on the inner surface of the casing, and the predetermined area is coated with a coating, and the coating is The material includes hot melt adhesive, and the viscosity of the coating is greater than a second preset value.
The battery of claim 14, wherein the predetermined area includes at least a first portion opposite to the area where the first foil layer is located.