CN219350610U

CN219350610U - Insulating film structure and battery

Info

Publication number: CN219350610U
Application number: CN202320345056.5U
Authority: CN
Inventors: 王海龙; 史童男; 丁佩岭; 胡玥; 杨超; 朱开鑫; 郭小森; 刘立淮
Original assignee: Svolt Energy Technology Co Ltd
Current assignee: Svolt Energy Technology Co Ltd
Priority date: 2023-02-28
Filing date: 2023-02-28
Publication date: 2023-07-14
Anticipated expiration: 2033-02-28

Abstract

The utility model relates to the technical field of batteries, in particular to an insulating film structure and a battery. The insulating film structure includes: the main body part comprises a side surface in sealing connection; the opening end is positioned at the upper end of the main body part, and the pole group is suitable for being installed in the main body part through the opening end; the main body part is made of microporous membrane, and the microporous membrane is suitable for passing electrolyte and is suitable for blocking particulate foreign matters. Through setting the upper end of main part to the open end to form one end open-ended bag column structure, be convenient for pack into the main part with the utmost point group from the open end in, and the airtight connection structure that the side of main part formed has the effect of blockking to the foreign matter granule that drops from the utmost point group, can prevent that the inside foreign matter granule of main part from migrating between insulating film structure and the battery casing along with electrolyte via the side, thereby avoid the battery casing to corrode phenomenon because of contacting the foreign matter granule, extension battery life.

Description

Insulating film structure and battery

Technical Field

The utility model relates to the technical field of batteries, in particular to an insulating film structure and a battery.

Background

After the assembly of the electrode group and the final welding of the electrode lug are completed, the lithium ion battery is generally wrapped with a layer of mylar film outside the electrode group to isolate the electrode group from the shell, so that the aim of improving the safety of the battery core is fulfilled. However, in the actual charge and discharge process of the lithium ion battery, the positive and negative electrode plates have certain expansion and contraction, and along with the expansion and contraction of the positive and negative electrode plates, electrolyte in the electrode plates and the diaphragm is inevitably extruded or absorbed, so that the circulating and reciprocating flow of free electrolyte and adsorbed electrolyte in the battery core is achieved. The conventional mylar film structure is characterized in that the film structure is directly wrapped on the outer side of the pole group, the bottom or the side edge of the film structure is not airtight, for example, round holes or cutting marks exist, in the charge and discharge process of a battery, the circulating reciprocating flow of electrolyte can drive particle foreign matters (such as positive and negative electrode main material particles which are not firmly bonded on pole pieces or particles which are easy to fall off in a die cutting position in the process of manufacturing the battery, and the like) to migrate, the particle foreign matters on pole pieces of the pole group inevitably migrate from the unsealed bottom or the side edge of the mylar film to the position between the mylar film and the shell, and then reach the position, close to the shell, of the bottom of the pole group, of the pole piece and the shell are caused to conduct electrons, and in addition, the naturally existing ion channels inside the battery core can generate corrosion of the lithium-embedded aluminum shell layer under proper conditions, so that the battery core fails.

Disclosure of Invention

Therefore, the technical problem to be solved by the utility model is to overcome the defect that the mylar film structure in the prior art cannot effectively block the migration of the particle foreign matters from the inside of the electrode group to the space between the mylar film and the shell along with the electrolyte, so as to provide an insulating film structure and a battery capable of blocking the migration of the foreign matters from the inside of the electrode group to the space between the mylar film and the shell along with the electrolyte.

In order to solve the above-described problems, the present utility model provides an insulating film structure including: a main body portion including a side surface to which a seal is attached; an open end located at an upper end of the body portion, the pole set being adapted to be received therein via the open end; the main body part is made of a microporous membrane, and the microporous membrane is suitable for passing electrolyte and is suitable for blocking particulate foreign matters.

Optionally, the main body part is cuboid.

Optionally, the height of the main body is greater than the height of the pole group, and the difference between the height of the main body and the height of the pole group is 0.5-4 mm.

Optionally, the width of the main body is greater than the width of the pole group, and the difference between the width of the main body and the width of the pole group is 0.5-4 mm.

Optionally, the length of the main body part is greater than the length of the pole group, and the difference between the length of the main body part and the length of the pole group is 0.5-4 mm.

Alternatively, the microporous membrane has a thickness of 10 to 100 μm.

Optionally, the microporous membrane comprises a substrate layer and a coating layer coated on at least one side of the substrate layer.

Optionally, the substrate layer is made of polypropylene or polyethylene, and/or the coating layer is made of a ceramic layer or a ceramic layer and an adhesive layer.

Optionally, the thickness of the coating is 0.5-5 um.

The present utility model also provides a battery including: the insulating film structure described above.

The utility model has the following advantages:

1. according to the insulating film structure provided by the utility model, the upper end of the main body part is set to be the open end, so that a bag-shaped structure with one end open is formed, the electrode group is conveniently arranged in the main body part from the open end, the airtight connection structure formed by the side surface of the main body part has a blocking effect on foreign particles falling from the electrode group, and the foreign particles in the main body part can be prevented from migrating between the insulating film structure and the battery shell along with electrolyte through the side surface, so that the phenomenon that the battery shell is corroded due to contact with the foreign particles is avoided, the service life of the battery is prolonged, and the production cost is reduced.

2. According to the insulating film structure provided by the utility model, the main body part is in a cuboid shape, the cuboid shape is simple to process, the insulating film structure can be attached to the shape of the pole group, and the use is convenient.

3. According to the insulating film structure provided by the utility model, the length, the width and the height of the insulating film structure are slightly larger than those of the electrode group, so that the insulating film can be ensured to effectively wrap the electrode group, the electrode is conveniently assembled into the insulating film structure, the working efficiency is improved, and then, in the battery production process, after the battery core baking process, the insulating film structure has obvious heat shrinkage, and the insulating film structure can be ensured to be tightly wrapped on the outer side of the electrode group, so that the insulating effect is achieved.

4. According to the insulating film structure provided by the utility model, the microporous film comprises the substrate layer and the coating, and the coating is coated on at least one side of the substrate layer, so that the strength and toughness of the insulating film can be improved, and the safety of a battery is improved.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present utility model, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

Fig. 1 shows a schematic structural view of an insulating film structure of an embodiment of the present utility model;

fig. 2 shows a schematic front view of the insulating film structure of fig. 1;

FIG. 3 shows a schematic side view of the insulating film structure of FIG. 1;

FIG. 4 shows a schematic top view of the insulating film structure of FIG. 1;

fig. 5 shows a schematic cross-sectional structure of an insulating film according to an embodiment of the present utility model.

Reference numerals illustrate:

10. a main body portion; 101. a base layer; 102. a coating; 11. a bottom surface; 121. a first side; 122. a second side; 20. an open end.

Detailed Description

The following description of the embodiments of the present utility model will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the utility model are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "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; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, the technical features of the different embodiments of the present utility model described below may be combined with each other as long as they do not collide with each other.

As shown in fig. 1 to 5, the insulating film structure provided in this embodiment includes: a main body 10 and an open end 20, the main body 10 including side surfaces connected in a sealed manner; an open end 20 is located at the upper end of the body portion 10, and a pole set is adapted to be fitted into the body portion 10 via the open end 20; the main body 10 is made of a microporous membrane, which is suitable for passing an electrolyte and for blocking particulate foreign matters. Wherein, the upper end refers to the end along the direction of the arrow in figure 1; the side surface comprises a bottom surface 11 opposite to the open end 20 and a circumferential surface between the bottom surface 11 and the open end 20, wherein the bottom surface 11 is located at one end of the main body 10 along the direction indicated by the arrow in fig. 1.

By using the insulating film structure of this embodiment, the upper end of the main body 10 is set to the open end 20, so as to form a bag-shaped structure with one open end, so that the electrode group is conveniently installed into the main body 10 from the open end 20, and the airtight connection structure formed by the side surface of the main body 10 has a blocking effect on foreign particles falling from the electrode group, so that the foreign particles in the main body 10 can be prevented from migrating between the insulating film structure and the battery case along with the electrolyte through the side surface, thereby avoiding the occurrence of corrosion of the battery case due to contact with the foreign particles, prolonging the service life of the battery, and reducing the production cost.

The insulating film structure and the electrode group are installed in the battery case, the material of the main body 10 is microporous film, the microporous film has insulativity, and due to the characteristics of the microporous film, electrolyte can pass through, but particulate foreign matters can not pass through, so that the particulate foreign matters falling from the pole piece can be blocked in the main body 10, wherein the main body 10 is in a bag shape with one open end, the inside of the main body 10 is suitable for accommodating the electrode group, and the electrode lugs of the electrode group extend out from the open end 20 and are connected with the upper cover of the battery case; during use of the battery, the open end 20 of the insulating film structure faces upward, and foreign particles are generally deposited downward, so that the foreign particles do not overflow from the open end 20 at the upper end; the pole group is a battery pole group, can be a single pole group or a plurality of pole groups stacked, and depends on the actual design of the battery.

In this embodiment, the main body 10 has a rectangular parallelepiped shape. An upper end surface of the rectangular parallelepiped is configured as the open end 20 without a solid portion, wherein the upper end surface refers to an end surface along a direction of an "upper" indicated by an arrow in fig. 1; the side surfaces of the main body 10 comprise a bottom surface 11 and a circumferential surface, the bottom surface 11 is rectangular, and the circumferential surface comprises two first side surfaces 121 and two second side surfaces 122 which are oppositely arranged. The cuboid is simple in shape processing, can be attached to the shape of the pole group, and is convenient to use.

Preferably, the main body 10 is integrally formed, so that there is no seam between the bottom 11 and the circumferential surface, and the sealing performance is good. It can be understood that the main body portion may be formed by splicing the bottom surface 11 and the circumferential surface, so that good connection tightness between the bottom surface 11 and the circumferential surface needs to be ensured, and no gap is formed, thereby achieving tightness between the bottom surface 11 and the circumferential surface.

In this embodiment, the height C of the main body 10 is greater than the height of the pole group, and the difference between the height C of the main body 10 and the height of the pole group is 0.5 to 4mm. By setting the height C of the main body 10 slightly higher than the pole group of the battery cell, the insulating film structure can effectively wrap the pole group in the height direction, and insulation between the pole group and the battery case is ensured. Wherein, height refers to the dimension along the "height direction" indicated by the arrow in fig. 1.

In this embodiment, the width of the main body 10 is greater than the width of the pole group, and the difference between the width of the main body 10 and the width of the pole group is 0.5 to 4mm. By providing the width D of the main body portion 10 slightly wider than the width of the pole group, the insulating film structure can effectively wrap the pole group in the width direction. Where width refers to the dimension along the "width direction" indicated by the arrow in fig. 1.

In this embodiment, the length of the main body 10 is greater than the length of the pole group, and the difference between the length of the main body 10 and the length of the pole group is 0.5 to 4mm. The insulation film structure can effectively wrap the pole group in the length direction by providing the length E of the main body part 10 to be slightly longer than the length of the pole group. Where length refers to the dimension along the "length direction" indicated by the arrow in fig. 1.

It should be noted that, through setting up the length, width, height that insulating film structure all slightly is greater than the length, width, height of utmost point group, guarantee that insulating film can effectively wrap up utmost point group to in the insulating film structure is assembled to the convenience, improve work efficiency, then, in battery production process, after electric core toasts the process, insulating film structure has obvious heat shrinkage, can guarantee that insulating film structure tightly wraps up in the utmost point group outside, plays insulating effect.

In this embodiment, the microporous membrane has a thickness of 10 to 100 μm, and can ensure insulation and at the same time can ensure smooth passage of ions in the electrolyte.

In this embodiment, the microporous membrane includes a base layer 101 and a coating layer 102, and the coating layer 102 is coated on at least one side of the base layer 101, so that the strength and toughness of the insulating film can be improved, thereby improving the safety of the battery. Preferably, the coating 102 is provided on both sides of the base layer 101, so that the strength and toughness of the insulating film are further improved.

In this embodiment, the base layer 101 is made of a polymer material such as polypropylene, polyethylene, or polyacrylic acid, and has mature technology and good stability. The material of the coating 102 is a ceramic layer, or the material of the coating 102 is a combination of a ceramic layer and a glue layer, specifically, when the coating 102 is disposed on both sides of the substrate layer 101, both the coating 102 may be a ceramic layer, or may be a combination of a ceramic layer and a glue layer, or one of the coating 102 is a combination of a ceramic layer and a glue layer. It should be noted that, the material and structure of the insulating film have the characteristics of microporous mechanism, so that the electrolyte can be effectively ensured to pass through, and meanwhile, foreign particles can be blocked from migrating between the main body 10 of the insulating film and the battery shell, so that the occurrence of an electronic path can be effectively prevented, and the traditional mylar film structure can be completely replaced.

In this embodiment, the thickness of the coating 102 is 0.5-5 um, which provides sufficient strength and toughness.

The present use novel still provides a battery, it includes: the insulating film structure described above. Specifically, the electrode group of the battery is mounted in the insulating film structure, and the insulating film structure and the electrode group are mounted in the battery case together. Preferably, the insulating film structure can be fixed on the inner wall of the battery shell through hot melting, so that the overall stability is improved, and the insulating film structure can be fixed on the inner wall of the battery shell instead of the inner wall of the battery shell, so that the battery shell is convenient to assemble.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the utility model.

Claims

1. An insulating film structure, characterized by comprising:

a main body portion including a side surface to which a seal is attached;

an open end located at an upper end of the body portion, the pole set being adapted to be received therein via the open end;

the main body part is made of a microporous membrane, and the microporous membrane is suitable for passing electrolyte and is suitable for blocking particulate foreign matters.

2. The insulating film structure according to claim 1, wherein the main body portion has a rectangular parallelepiped shape.

3. The insulating film structure according to claim 2, wherein the height of the main body portion is greater than the height of the pole group, and a difference between the height of the main body portion and the height of the pole group is 0.5 to 4mm.

4. The insulating film structure according to claim 2, wherein the width of the main body portion is larger than the width of the pole group, and a difference between the width of the main body portion and the width of the pole group is 0.5 to 4mm.

5. The insulating film structure according to claim 2, wherein the length of the main body portion is greater than the length of the pole group, and a difference between the length of the main body portion and the length of the pole group is 0.5 to 4mm.

6. The insulating film structure according to any one of claims 1 to 5, wherein the microporous film has a thickness of 10 to 100 μm.

7. The insulating film structure of any one of claims 1 to 5, wherein said microporous film comprises a base layer and a coating layer, said coating layer being coated on at least one side of said base layer.

8. The insulating film structure according to claim 7, wherein the base layer is made of polypropylene or polyethylene, and/or the coating layer is made of a ceramic layer or a ceramic layer and a glue layer.

9. The insulating film structure according to claim 7, wherein the thickness of the coating layer is 0.5 to 5um.

10. A battery, comprising: the insulating film structure of any one of claims 1 to 9.