Protective sheet and battery cell

Abstract

The utility model provides a protective sheet and a battery cell, the protective sheet is arranged at a pressure relief hole of a battery cell shell corresponding to an explosion-proof valve, the protective sheet is provided with a thinning area corresponding to the pressure relief hole, the thinning area is formed by a groove arranged on the protective sheet, and the groove is arranged along the edge of the pressure relief hole. According to the protection sheet disclosed by the utility model, the thinning area corresponding to the pressure relief hole is arranged, and the thinning area is formed by the groove, so that when thermal runaway occurs in the battery cell, the opening of the explosion-proof valve is facilitated through the fusing of the thinning area, and high-temperature gas sprayed out of the explosion-proof valve can flow out through the protection sheet, so that the pressure relief effect of the explosion-proof valve can be ensured, and the service life of the explosion-proof valve is prolonged. And the safety of the battery cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and in particular to a protective sheet; at the same time, the utility model also relates to a battery core provided with the protective sheet, and a battery pack provided with the battery core. Background Art

[0002] As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of lithium-ion batteries are increasing. Lithium cells are the core components of battery pack safety and assembly, and their structural design is crucial to cell safety. The current cell structure mostly uses top patches, blue films, etc. to insulate the cells, and PET (short for polyethylene terephthalate) patches are attached to the cover explosion-proof valve for protection.

[0003] The explosion-proof valve in the prior art is covered inside the blue film, which will affect the normal opening of the explosion-proof valve and seriously affect the safety performance of the battery cell. The explosion-proof valve is directly opened to avoid the setting, so that the insulation and creepage distance of the exposed part of the battery cell shell cannot meet the safety requirements. Furthermore, when the battery cell has thermal runaway, the protective patch currently used has a high melting point and high bonding strength, and cannot be quickly melted and detached, thereby affecting the pressure relief of the explosion-proof valve and further affecting the safety of the battery cell. Utility Model Content

[0004] In view of this, the utility model aims to provide a protective sheet to improve the safety of thermal runaway of a battery cell.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] A protective sheet is arranged at a pressure relief hole of a battery cell shell corresponding to an explosion-proof valve, and the protective sheet has a thinning area arranged corresponding to the pressure relief hole, the thinning area is formed by a groove arranged on the protective sheet, and the groove is arranged along the edge of the pressure relief hole.

[0007] Furthermore, the thinned area separates the protective sheet into a main body portion located on the inner side and a connecting portion located on the outer side; the ratio of the area of ​​the main body portion to the area of ​​the protective sheet is 0.5-0.8.

[0008] Furthermore, the groove is arranged on a side of the protection sheet facing toward or facing away from the explosion-proof valve.

[0009] Furthermore, the depth L1 of the groove is between 0.03 mm and 0.1 mm; and / or the width L2 of the groove is between 0.5 mm and 4 mm.

[0010] Furthermore, the protective sheet is made of any one of polyvinyl acetate, polycaprolactone, soft polyvinyl chloride plastic, and low-density polyethylene.

[0011] Compared with the prior art, the utility model has the following advantages:

[0012] The protective sheet described in the utility model is provided with a thinning area corresponding to the pressure relief hole. The thinning area is formed by a groove provided on the protective sheet. The groove is provided along the edge of the pressure relief hole. When thermal runaway occurs inside the battery cell, the thinning area can be melted to facilitate the opening of the explosion-proof valve. The high-temperature gas ejected from the explosion-proof valve can flow out through the protective sheet, thereby ensuring the pressure relief effect of the explosion-proof valve and further improving the safety of the battery cell.

[0013] In addition, the setting of the area ratio range of the main body and the protective sheet is conducive to pressure relief in cooperation with the explosion-proof valve on the premise of meeting the protection requirements, and has good pressure relief efficiency. Setting the groove on the side of the protective sheet facing downward to the explosion-proof valve further facilitates the melting of the groove, and setting the groove on the side away from the explosion-proof valve also has the advantage of easy implementation. The setting of the groove depth and width range can facilitate the melting of the thinning area on the premise of meeting the strength requirements of the protective sheet. The selection of the material of the protective sheet is not only conducive to protecting the explosion-proof valve from external scratches and extrusion, but also can quickly melt in the event of thermal runaway, thereby facilitating the opening of the explosion-proof valve.

[0014] In addition, another object of the utility model is to provide a battery core, comprising a shell having a receiving cavity, a cover for sealing the receiving cavity, an explosion-proof valve provided on the shell, and the protective sheet as described above;

[0015] The shell is provided with a pressure relief hole, the explosion-proof valve is arranged in the accommodating cavity corresponding to the pressure relief hole, and the protection sheet is arranged outside the accommodating cavity corresponding to the explosion-proof valve.

[0016] Furthermore, the shell is provided with a protruding portion protruding out of the accommodating cavity, and the pressure relief hole is provided on the protruding portion.

[0017] Furthermore, the cover body includes two cover plates arranged at two opposite sides of the shell, and the two cover plates are respectively provided with a positive electrode column and a negative electrode column.

[0018] Furthermore, it also includes a pole group arranged in the accommodating cavity.

[0019] Furthermore, a protective plate corresponding to the explosion-proof valve is provided on the pole group; the protective plate has an abutting protrusion abutting against the shell, and a vent corresponding to the explosion-proof valve is provided on the protective plate.

[0020] The battery cell described in the utility model, by arranging the explosion-proof valve corresponding to the pressure relief hole in the accommodating cavity, and arranging the protective sheet corresponding to the explosion-proof valve outside the accommodating cavity, can facilitate the opening of the explosion-proof valve with the help of the setting of the thinned area, and the high-temperature gas ejected from the explosion-proof valve can flow out through the protective sheet, thereby ensuring the pressure relief effect of the explosion-proof valve, and further facilitating the improvement of the safety of the battery cell.

[0021] In addition, by setting the pressure relief hole on the protruding part of the shell, it is convenient to arrange the explosion-proof valve. The cover plates are arranged on the two opposite sides of the shell, and the positive pole and the negative pole are arranged on the two cover plates respectively, which is convenient to meet the use requirements of the battery cell. By setting a protective plate with abutting protrusions and a vent, it is convenient to discharge hot gas during thermal runaway while protecting the electrode group, which can further improve the safety of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0023] Figure 1 This is a schematic diagram of the structure of the protective sheet according to an embodiment of the utility model at one viewing angle;

[0024] Figure 2 for Figure 1 A cross-sectional view of the middle protective sheet;

[0025] Figure 3 This is a disassembled diagram of the battery cell housing structure described in an embodiment of the utility model;

[0026] Figure 4 This is a schematic diagram of the structure of the battery cell housing structure without an explosion-proof valve and a protective sheet according to an embodiment of the utility model;

[0027] Figure 5 It is a structural schematic diagram of the battery cell housing structure according to an embodiment of the utility model at one viewing angle;

[0028] Figure 6 for Figure 5 AA direction section view in.

[0029] Description of reference numerals:

[0030] 1. Shell; 2. Explosion-proof valve; 3. Protective sheet; 4. Protective plate; 5. Electrode group;

[0031] 101, pressure relief hole; 102, blue film; 103, cover plate; 104, protruding part;

[0032] 300, thinning area; 301, main body; 302, connecting part; 303, groove;

[0033] 401. abutment protrusion; 402. ventilation hole. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0035] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0036] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection", and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0038] Embodiment 1

[0039] This embodiment relates to a protective sheet 3, which is arranged at the pressure relief hole 101 of the battery cell housing 1 corresponding to the explosion-proof valve 2. The protective sheet 3 has a thinning area 300 arranged corresponding to the pressure relief hole 101, and the thinning area 300 is formed by a groove 303 arranged on the protective sheet 3, and the groove 303 is arranged along the edge of the pressure relief hole 101.

[0040] The protective sheet 3 described in this embodiment is provided with a thinning area 300 corresponding to the pressure relief hole 101. The thinning area 300 is formed by a groove 303 provided on the protective sheet 3. The groove 303 is provided along the edge of the pressure relief hole 101. When thermal runaway occurs inside the battery cell, the thinning area 300 can be melted to facilitate the opening of the explosion-proof valve 2. The high-temperature gas ejected from the explosion-proof valve 2 can flow out through the protective sheet 3, thereby ensuring the pressure relief effect of the explosion-proof valve 2 and further improving the safety of the battery cell.

[0041] In terms of specific structure, Figure 1 and Figure 2As shown in , the thinning area 300 separates the protective sheet 3 into a main body portion 301 located on the inside and a connecting portion 302 located on the outside; the ratio of the area of ​​the main body portion 301 to the area of ​​the protective sheet 3 is 0.5-0.8. Here, the setting of the area ratio range of the main body portion 301 and the protective sheet 3 is conducive to pressure relief with the explosion-proof valve 2 while meeting the protection requirements, and has a good pressure relief efficiency. In specific implementation, for example, the area ratio can be 0.5, 0.6, 0.7 or 0.8, etc.

[0042] The connection part 302 is used to connect with the housing 1. For example, the connection part 302 is bonded to the housing 1 at the circumferential edge of the pressure relief hole 101 by gluing. In this embodiment, the thickness at the groove 303 is the smallest, which is conducive to melting when the temperature rises. The groove 303 is arranged along the edge of the pressure relief hole 101, which is conducive to increasing the ventilation area on the protective sheet 3 and further improving the pressure relief efficiency.

[0043] As a preferred arrangement, Figure 6 As shown in , the groove 303 in this embodiment is arranged on the side of the protective sheet 3 facing the explosion-proof valve 2. Specifically, the arrangement of the groove 303 is conducive to increasing the contact area between the thinning area 300 and the hot gas, and can improve the fusing efficiency of the thinning area 300. When the hot gas blows onto the thinning area 300 after fusing, it is conducive to forming a vent on the protective sheet 3, and the area of ​​the vent can be larger, thereby improving the discharge efficiency of the hot gas during thermal runaway. Of course, it is also feasible to arrange the groove 303 on the side of the protective sheet 3 facing away from the explosion-proof valve 2, which is also conducive to the opening and pressure relief of the explosion-proof valve 2.

[0044] In this embodiment, the depth L1 of the groove 303 is between 0.03 mm and 0.1 mm, and the width L2 of the groove 303 is between 0.5 mm and 4 mm. The depth and width range of the groove 303 can be set to facilitate the fusing of the thinning area 300 while meeting the strength requirements of the protective sheet 3. In specific implementation, for example, the depth L1 of the groove 303 can be 0.03 mm, 0.06 mm, 0.09 mm or 0.1 mm, etc., and the width L2 of the groove 303 can be 0.5 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm or 4 mm, etc.

[0045] Among them, when the depth L1 of the groove 303 is less than 0.03mm, the thickness of the thinned area 300 will be too small, and the thinned area 300 will easily melt before the temperature of the battery cell is abnormal, thereby affecting the protective effect of the protective sheet 3. When the depth of the groove 303 is greater than 0.1mm, the thinned area 300 is not easy to melt during thermal runaway, thereby affecting the pressure relief efficiency of the explosion-proof valve 2, and further affecting the safety of the battery cell. In addition, when the width L2 of the groove 303 is less than 0.5mm, the contact area between the groove 303 and the airflow is small, making it difficult for the thinned area 300 to melt during thermal runaway. When the width L2 of the groove 303 is greater than 4mm, it will affect the structural strength of the protective sheet 3, thereby affecting the protective effect of the protective sheet 3.

[0046] In order to facilitate the fusing of the thinned area 300 on the protective sheet 3, the protective sheet 3 in this embodiment is preferably made of a material with a low melting point. For example, the melting temperature F of the thinned area 300 can be 30°C < F < 125°C, and the material is not limited to plastics and resins. The valve opening temperature of the battery cell thermal runaway is generally 130-140°C. The protective sheet 3 should protect the explosion-proof valve 2 from external scratches and extrusions under normal circumstances, and enable the thinned area 300 to fuse quickly when the battery cell thermal runaways, so that the explosion-proof valve 2 can open the valve without obstacles.

[0047] In specific implementation, as an optional implementation, the protective sheet 3 is made of any one of polyvinyl acetate, polycaprolactone, soft polyvinyl chloride plastic, and low-density polyethylene. The selection of the material of the protective sheet 3 is not only conducive to protecting the explosion-proof valve 2 from external scratches and extrusions, but also can be quickly melted in the event of thermal runaway, thereby facilitating the opening of the explosion-proof valve 2.

[0048] Embodiment 2

[0049] This embodiment relates to a battery cell, which overall comprises a housing 1 having a housing cavity, a cover for sealing the housing cavity, an explosion-proof valve 2 provided on the housing 1, and a protective sheet 3 as described in the first embodiment. A pressure relief hole 101 is provided on the housing 1, the explosion-proof valve 2 is provided in the housing cavity corresponding to the pressure relief hole 101, and the protective sheet 3 is provided outside the housing cavity corresponding to the explosion-proof valve 2.

[0050] Based on the above overall introduction, the structure of the battery cell described in this embodiment is as follows Figures 3 to 6 As shown in , the pressure relief hole 101 is arranged on one side of the thickness direction of the housing 1. Preferably, the pressure relief hole 101, the explosion-proof valve 2 and the protective sheet 3 in this embodiment are all in the shape of oblong holes, which is convenient for arrangement and implementation. Of course, the shapes of the pressure relief hole 101, the explosion-proof valve 2 and the protective sheet 3 can also be set according to the use requirements.

[0051] To facilitate the installation of the explosion-proof valve 2 in the accommodating chamber, Figure 3 and Figure 6As shown in , the housing 1 is provided with a protruding portion 104 protruding outward from the accommodating cavity, and the pressure relief hole 101 is provided on the protruding portion 104. By providing the pressure relief hole 101 on the protruding portion 104 of the housing 1, it is beneficial to increase the space where the explosion-proof valve 2 is installed. The explosion-proof valve 2 is located on the inner side of the pressure relief hole 101, and the edges around the explosion-proof valve 2 are connected to the inner side wall of the protruding portion 104. Such a setting is beneficial to the arrangement of the explosion-proof valve 2, and at the same time, it can also reduce the space occupied in the accommodating cavity.

[0052] like Figure 5 As shown in , in this embodiment, a blue film 102 with an insulating effect can also be set on the outer periphery of the housing 1, and a avoidance hole is opened on the blue film 102 corresponding to the explosion-proof valve 2, and the protruding part 104 extends out of the avoidance hole. Figure 1 As shown in the figure, the cover body in this embodiment includes two cover plates 103 arranged on two opposite sides of the housing 1, and the two cover plates 103 are respectively provided with a positive electrode column and a negative electrode column. The two cover plates 103 and the two cover plates 103 are respectively provided with a positive electrode column and a negative electrode column, which is conducive to meeting the use requirements of the battery cell.

[0053] The battery cell in this embodiment further includes a pole group 5 disposed in the accommodation cavity. As a preferred embodiment, Figure 6 As shown in FIG. 1 , a protective plate 4 corresponding to the explosion-proof valve 2 is provided on the pole group 5. The protective plate 4 has an abutting protrusion 401 abutting against the housing 1, and a vent corresponding to the explosion-proof valve 2 is provided on the protective plate 4.

[0054] Specifically, the protective plate 4 is connected to one side of the electrode group 5 in the thickness direction and is located between the explosion-proof valve 2 and the electrode group 5, so as to protect the explosion-proof valve 2. The abutment protrusions 401 are arranged on both sides of the protective plate 4 in the width direction and extend along the length direction of the protective plate 4, so as to ensure the abutment effect between the protective plate 4 and the housing 1, and further improve the installation stability of the electrode group 5 in the housing 1.

[0055] The ventilation part in this embodiment includes a plurality of ventilation holes 402 provided on the protective plate 4, so as to facilitate the hot air inside the battery core to flow into the explosion-proof valve 2 through the ventilation hole and release pressure through the explosion-proof valve 2. In addition, the protective plate 4 has a simple structure, is easy to arrange and implement, and has a good use effect.

[0056] The battery cell of this embodiment, by optimizing the structure of the protection sheet 3, can not only arrange the explosion-proof valve 2 on the battery cell housing 1, but also the thinned area 300 on the protection sheet 3 is melted in the event of thermal runaway, which is beneficial to the opening of the explosion-proof valve 2, thereby facilitating the safety of the battery cell in the event of thermal runaway.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A protective sheet, arranged at the pressure relief hole of the battery cell housing corresponding to the explosion-proof valve, characterized in that: The protection sheet has a thinning area arranged corresponding to the pressure relief hole, and the thinning area is formed by a groove arranged on the protection sheet, and the groove is arranged along the edge of the pressure relief hole.

2. The protective sheet according to claim 1, characterized in that: The thinned area divides the protective sheet into a main body portion located on the inner side and a connecting portion located on the outer side; The ratio of the area of ​​the main body portion to the area of ​​the protective sheet is 0.5-0.

8.

3. The protective sheet according to claim 2, characterized in that: The groove is arranged on a side of the protection sheet facing toward or facing away from the explosion-proof valve.

4. The protective sheet according to claim 2, characterized in that: The depth L1 of the groove is between 0.03 mm and 0.1 mm; and / or, The width L2 of the groove is between 0.5 mm and 4 mm.

5. The protective sheet according to claim 1, characterized in that: The protective sheet is made of any one of polyvinyl acetate, polycaprolactone, soft polyvinyl chloride plastic and low-density polyethylene.

6. A battery cell, characterized in that: It comprises a shell having a receiving cavity, a cover body for sealing the receiving cavity, an explosion-proof valve provided on the shell, and a protective sheet according to any one of claims 1 to 5; The shell is provided with a pressure relief hole, the explosion-proof valve is arranged in the accommodating cavity corresponding to the pressure relief hole, and the protection sheet is arranged outside the accommodating cavity corresponding to the explosion-proof valve.

7. The battery cell according to claim 6, characterized in that: The shell is provided with a protruding portion protruding out of the accommodating cavity, and the pressure relief hole is provided on the protruding portion.

8. The battery cell according to claim 6, characterized in that: The cover body comprises two cover plates arranged at two opposite sides of the shell, and the two cover plates are respectively provided with a positive pole column and a negative pole column.

9. The battery cell according to claim 6, characterized in that: It also includes a pole group arranged in the accommodating cavity.

10. The battery cell according to claim 9, characterized in that: The pole group is provided with a protective plate corresponding to the explosion-proof valve; The protection plate has an abutting protrusion abutting against the shell, and a vent portion corresponding to the explosion-proof valve is arranged on the protection plate.

Images