Protective structure and battery pack

Abstract

The utility model provides a protection structure and a battery pack. The protection structure comprises a protection main body, the protection main body is constructed to wrap the periphery of a roll core, the protection main body comprises a plurality of containing cavities, filler is arranged in at least part of the containing cavities, the filler is constructed to be decomposed at a preset temperature and generate non-combustible gas, and the non-combustible gas can be discharged from the containing cavities; the preset temperature is higher than the highest working temperature of the roll core and lower than the spontaneous combustion temperature of the roll core. The protection structure provided by the technical scheme of the utility model can solve the problem that the battery cell is easy to generate thermal runaway at high temperature.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and in particular to a protective structure and a battery pack. Background Art

[0002] With the development of electric vehicles and the improvement of electric vehicle performance, the performance of batteries as power is also constantly improving. Electric vehicles require batteries with short charging time, long driving range and long service life. Therefore, batteries must have high energy density, high-rate charge and discharge, and long life cycle. Then, when the battery capacity is increased and the charge and discharge current increases, it will easily lead to thermal runaway. The reason is that the high-rate charge and discharge of the battery will generate a lot of heat. If the heat is not dissipated in time, it will cause thermal runaway and bring safety hazards. Therefore, it is necessary to effectively deal with the heat generated during the operation of the battery to accelerate the dissipation or reduce the heat generation.

[0003] At present, the main method to accelerate heat dissipation is to monitor the surface temperature of the battery, and perform air cooling or water cooling when the temperature exceeds the standard to accelerate heat dissipation. However, this method does not significantly reduce the temperature of the battery cell. The battery cell temperature is high and thermal runaway is very likely to occur. Utility Model Content

[0004] The main purpose of the utility model is to provide a protective structure and a battery pack, which can solve the problem that the battery core is prone to thermal runaway at high temperatures.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the utility model, a protective structure is provided, including: a protective body, the protective body is constructed to be wrapped around the outer periphery of the winding core, the protective body includes a plurality of accommodating cavities, at least some of the accommodating cavities are provided with fillers, the fillers are constructed to decompose at a preset temperature and produce non-combustible gas, and the non-combustible gas can be discharged from the accommodating cavity, and the preset temperature is greater than the maximum working temperature of the winding core and lower than the auto-ignition temperature of the winding core.

[0006] Furthermore, the protective body comprises a first concave-convex protective body, the first concave-convex protective body is a wavy structure, the first concave-convex protective body comprises a plurality of first convex portions and a plurality of first concave portions, the plurality of first convex portions and the plurality of first concave portions are alternately arranged along a first direction, and each first convex portion can form a receiving cavity; and / or the filler (20) is one or more of ammonium bicarbonate, sodium bicarbonate, potassium bicarbonate, and ammonium chloride.

[0007] Furthermore, the protective body also includes a second concave-convex protective split body, which is a wavy structure. The second concave-convex protective split body includes multiple second convex portions and multiple second concave portions. The multiple second convex portions and the multiple second concave portions are alternately arranged along the first direction, and each second convex portion can form an accommodating cavity. The multiple first convex portions are arranged one-to-one with the multiple second convex portions, and the multiple first concave portions are arranged one-to-one with the multiple second concave portions, and the correspondingly arranged first concave portions and the second concave portions form an accommodating cavity.

[0008] Furthermore, the protective body also includes a corrugated paper structure, which includes a wavy installation body and a connecting structure. The connecting structure is arranged on one side of the wavy installation body and forms a plurality of accommodating cavities with the wavy installation body.

[0009] Furthermore, the wavy mounting body includes a plurality of wave crests and a plurality of wave troughs, and the plurality of wave crests and the plurality of wave troughs are alternately arranged along a first direction. The number of corrugated paper structures is two, and the wavy mounting bodies of the two corrugated paper structures are arranged opposite to each other. The plurality of wave crests of the two wavy mounting bodies are arranged one by one in correspondence, and the plurality of wave troughs of the two wavy mounting bodies are arranged one by one in correspondence, and the two corresponding wave crests are bonded and fixed, and the two corresponding wave troughs form a accommodating cavity.

[0010] Furthermore, the volume occupied by the filler is less than or equal to 30% of the volume of the accommodating cavity.

[0011] Furthermore, the protection body also includes a sealing structure, which is coated on the outer circumference of the protection body to seal the accommodating cavity.

[0012] Furthermore, the sealing structure is made of polyethylene or polypropylene material.

[0013] Furthermore, the thickness of the sealing structure ranges from 5 μm to 20 μm.

[0014] According to another aspect of the present invention, a battery pack is provided, comprising: a shell; a winding core installed in the shell; and the above-mentioned protective structure, the protective structure covering the outer periphery of the winding core.

[0015] By applying the technical solution of the utility model, the protective body is wrapped around the outer periphery of the core. When the temperature of the core is too high, the filler decomposes, and the decomposition process absorbs heat and can absorb part of the heat. At the same time, the filler decomposes to produce non-combustible gas, which can reduce the oxygen concentration inside the core. The non-combustible gas is discharged from the accommodating cavity. The discharge of the non-combustible gas can quickly take away the heat and reduce the temperature of the core. After the filler in the accommodating cavity decomposes, the protective body is a hollow structure, which can also delay the transfer of heat from the external environment to the inside of the core. Through the above-mentioned configuration, it is possible to prevent the temperature inside the core from continuing to rise and the occurrence of side reactions, and avoid thermal runaway of the core. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary 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 drawings:

[0017] Figure 1 A schematic diagram showing the structure of a protective structure of an embodiment of the utility model; and

[0018] Figure 2 A structural schematic diagram of a protective structure of another embodiment of the utility model is shown.

[0019] The above drawings include the following reference numerals:

[0020] 10. Protective body; 11. First concave-convex protective body; 111. First convex portion; 112. First concave portion; 12. Second concave-convex protective body; 121. Second convex portion; 122. Second concave portion; 13. Accommodating cavity; 14. Wave-shaped installation body; 15. Wave crest; 16. Wave trough; 17. Connection structure; 20. Filler; 30. Sealing structure. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] A lithium battery separator is disclosed in Chinese patent CN201310421424.0, which is composed of a base layer and an organic or inorganic hollow particle film layer arranged on one side of the base layer or on both sides of the base layer; the lithium battery separator is coated with the hollow particle film layer on the substrate, and after the separator is punctured, the hollow structure can reduce the overall heat conduction rate, so that the substrate can have more time to melt and close the pores, thereby playing a role of safety blocking. The lithium battery separator can ensure the safety of battery use. At the same time, compared with the multi-layer structure separator and the ceramic coating separator, the hollow particles can reduce the overall weight of the battery, and the battery capacity can be greatly improved. The above-mentioned lithium battery separator is applied to the inside of the battery cell, and it takes effect during puncture, and cannot achieve thermal protection of the battery cell.

[0023] Chinese patent CN201922147391.0 discloses a lithium battery thermal runaway protection pad, which, when used on the surface of lithium battery packaging, can effectively deal with the high temperature and heat on the surface of the packaging when the lithium battery thermal runaways. When the temperature of the top outer surface of the package reaches 120-200°C, the gel generates gas to cause the gel sheet to rupture and release the gel, and the gel spreads on the corrugated paper on the surface of the package to absorb heat and cool it down. The above-mentioned lithium battery thermal runaway protection pad is a surface packaging component used to deal with the high temperature and heat generated by thermal runaway of lithium batteries. It is a post-processing measure and cannot avoid the occurrence of thermal runaway of the battery cell.

[0024] In Chinese patent CN201910639056.4, a soft-pack shell of a lithium battery and a soft-pack lithium battery using the same are disclosed. A plurality of flexible protrusions are arranged on the inner side of the soft-pack shell facing the lithium battery core. The flexible protrusions are on the soft-pack shell itself or attached to the soft-pack shell by pasting or hot pressing. The flexible protrusions are hollow and filled with gas and / or solid fillers; the flexible protrusions can also be solid; the flexible protrusions are one or a combination of corrugated, strip-shaped, corrugated, lattice-shaped, dense cylindrical, and grid shapes; or, the flexible protrusions are a plurality of non-intersecting corrugated or strip-shaped or corrugated protrusions, and the corrugated protrusions, strip-shaped protrusions, and corrugated protrusions can be continuous or discontinuous. The above-mentioned soft-pack shell of the lithium battery can reduce shock and protect the battery from strong extrusion or tolerance to extrusion by arranging a plurality of flexible protrusions on the inner side facing the lithium battery core, but has no effect on thermal protection.

[0025] In order to solve the above problems, refer to Figure 1 and Figure 2 As shown, the utility model provides a protection structure, which includes: a protection body 10, the protection body 10 is constructed to be wrapped around the outer periphery of the winding core, the protection body 10 includes a plurality of accommodating cavities 13, at least some of the accommodating cavities 13 are provided with fillers 20, the fillers 20 are constructed to decompose at a preset temperature and generate non-flammable gas, and the non-flammable gas can be discharged from the accommodating cavities 13, the preset temperature is greater than the maximum working temperature of the winding core and lower than the auto-ignition temperature of the winding core.

[0026] In this embodiment, the protective body 10 is wrapped around the outer periphery of the core, and the initial form of the filler 20 is solid. When the core temperature is too high, the filler 20 decomposes, and the decomposition process absorbs heat and can absorb part of the heat. At the same time, the filler 20 decomposes to produce non-combustible gas, which can reduce the oxygen concentration inside the core. The non-combustible gas is discharged from the accommodating cavity 13. The discharge of the non-combustible gas can quickly take away the heat and reduce the core temperature. After the filler 20 in the accommodating cavity 13 decomposes, the protective body 10 is a hollow structure, which can also delay the transfer of heat from the external environment to the inside of the core. Through the above-mentioned settings, it is possible to prevent the temperature inside the core from rising and the occurrence of side reactions, and avoid thermal runaway of the core.

[0027] It should be noted that the protective body 10 is wrapped around the outer periphery of the roll core and together with the roll core, when the filler decomposes at a preset temperature to produce non-combustible gas, the non-combustible gas can be discharged in the following two ways. One is to open a plurality of exhaust channels connected to the accommodating cavity 13 on the protective body 10, and the non-combustible gas is discharged through the exhaust channels; alternatively, the entire roll core is broken, that is, the protective body 10 of the roll core is burst, and the non-combustible gas is directly discharged.

[0028] In one embodiment, the filler 20 is one or more of ammonium bicarbonate, sodium bicarbonate, potassium bicarbonate, and ammonium chloride. The above ammonium bicarbonate, sodium bicarbonate, potassium bicarbonate, and ammonium chloride are all soluble in water or solvents, and can be filled in the receiving cavity 13 by impregnating the protective body 10 and then drying the solvent to make the filler 20 in a solid form.

[0029] In one embodiment, the preset temperature ranges from 60°C to 150°C.

[0030] like Figure 1 As shown, in one embodiment of the utility model, the protective body 10 includes a first concave-convex protective body 11, the first concave-convex protective body 11 is a wavy structure, the first concave-convex protective body 11 includes a plurality of first convex portions 111 and a plurality of first concave portions 112, the plurality of first convex portions 111 and the plurality of first concave portions 112 are alternately arranged along a first direction, and each first convex portion 111 can form a accommodating cavity 13.

[0031] In this embodiment, each first protrusion 111 can form a accommodating cavity 13. When the protective body 10 is wrapped around the outer periphery of the winding core, the first protrusion 111 is facing the winding core. At this time, the first concave-convex protective body 11 can limit the filler 20 between the first protrusion 111 and the outer peripheral surface of the winding core, and the filler 20 is arranged in the accommodating cavity 13 formed by at least part of the first protrusion 111.

[0032] In one embodiment, the distance L between two adjacent first recesses 112 ranges from 3 mm to 15 mm.

[0033] In this embodiment, there is a certain distance between two adjacent first recesses 112 to provide space for installing the filler 20 .

[0034] like Figure 1 As shown, in one embodiment of the utility model, the protective body 10 also includes a second concave-convex protective body 12, the second concave-convex protective body 12 is a wavy structure, the second concave-convex protective body 12 includes a plurality of second convex portions 121 and a plurality of second concave portions 122, the plurality of second convex portions 121 and the plurality of second concave portions 122 are alternately arranged along the first direction, each second convex portion 121 can form an accommodating cavity 13, the plurality of first convex portions 111 and the plurality of second convex portions 121 are arranged one-to-one correspondingly, the plurality of first concave portions 112 and the plurality of second concave portions 122 are arranged one-to-one correspondingly, and the correspondingly arranged first concave portions 112 and the second concave portions 122 form an accommodating cavity 13.

[0035] In this embodiment, a plurality of first convex portions 111 and a plurality of second convex portions 121 are arranged one by one, and the correspondingly arranged first convex portions 111 and second convex portions 121 are bonded and fixed to connect the first concave-convex protection body 11 and the second concave-convex protection body 12 together. At this time, the correspondingly arranged first concave portions 112 and the second concave portions 122 form a closed accommodating cavity 13, which can be used to install the filler 20. At the same time, each second convex portion 121 can form an accommodating cavity 13, and when the protective body 10 is wrapped around the outer periphery of the winding core, the second convex portion 121 is directed toward the winding core. At this time, the second concave-convex protection body 12 can limit the filler 20 between the second convex portion 121 and the outer peripheral surface of the winding core.

[0036] In one embodiment, the cross section of the filler 20 is circular or triangular, or may be other irregular shapes.

[0037] like Figure 2 As shown, in one embodiment of the utility model, the protective body 10 also includes a corrugated paper structure, which includes a wavy mounting body 14 and a connecting structure 17. The connecting structure 17 is arranged on one side of the wavy mounting body 14 and surrounds a plurality of accommodating cavities 13 with the wavy mounting body 14.

[0038] In this embodiment, the connecting structure 17 is located on one side of the wavy mounting body 14 and is connected to the wavy mounting body 14. At this time, the wavy mounting body 14 can form a plurality of closed accommodating cavities 13 with the connecting structure 17, and at least part of the accommodating cavities 13 is provided with fillers 20. When the protective body 10 is wrapped around the outer periphery of the winding core, the side where the connecting structure 17 is located faces the winding core.

[0039] In one embodiment, the entire corrugated paper structure is made of polyethylene or polypropylene material, and may also be made of elastic material (such as rubber).

[0040] like Figure 2 As shown, in one embodiment of the utility model, the wavy mounting body 14 includes a plurality of crests 15 and a plurality of troughs 16, and the plurality of crests 15 and the plurality of troughs 16 are alternately arranged along a first direction. The number of corrugated paper structures is two, and the wavy mounting bodies 14 of the two corrugated paper structures are arranged opposite to each other. The plurality of crests 15 of the two wavy mounting bodies 14 are arranged one by one, and the plurality of troughs 16 of the two wavy mounting bodies 14 are arranged one by one, and the two corresponding crests 15 are bonded and fixed, and the two corresponding troughs 16 form a accommodating cavity 13.

[0041] In this embodiment, the two corrugated paper structures are bonded and fixedly connected as a whole through the correspondingly arranged wave peaks 15. The multiple wave peaks 15 and the connecting structure 17 can enclose a plurality of accommodating cavities 13. The two wave troughs 16 correspondingly arranged on the two corrugated paper structures can also form an accommodating cavity 13. At least one filler 20 is arranged in at least part of the accommodating cavity 13. When the temperature of the core is too high, the filler 20 decomposes to produce non-combustible gas, and the non-combustible gas is released from the accommodating cavity 13. The decomposition process of the filler 20 absorbs a large amount of heat, which can avoid the increase of the internal temperature of the core and the occurrence of side reactions, and avoid thermal runaway of the core.

[0042] In one embodiment of the present invention, the volume occupied by the filler 20 is less than or equal to 30% of the volume of the accommodating cavity 13 .

[0043] In this embodiment, the volume occupied by the filler 20 is less than or equal to 30% of the volume of the accommodating cavity 13 , so as to avoid excessive weight and reduced plasticity of the protective body 10 caused by excessive filler 20 .

[0044] like Figure 1 As shown, in one embodiment of the present invention, the protection body 10 further includes a sealing structure 30 , and the sealing structure 30 is coated on the outer periphery of the protection body 10 to seal the accommodating cavity 13 .

[0045] In this embodiment, the sealing structure 30 is coated on the outer periphery of the protective body 10, and can seal the accommodating cavity 13 to prevent the filler 20 in the accommodating cavity 13 from falling out. The winding core coated with the protective body 10 is placed in the housing, and the electrolyte is injected to form a battery pack. At this time, the setting of the sealing structure 30 can isolate the electrolyte and prevent the electrolyte from entering the accommodating cavity 13. When the temperature of the winding core is too high, the filler 20 decomposes to produce non-combustible gas, and the sealing structure 30 ruptures, so that the non-combustible gas can be discharged from the accommodating cavity 13.

[0046] In one embodiment of the present invention, the sealing structure 30 is made of polyethylene or polypropylene.

[0047] In this embodiment, the sealing structure 30 is made of polyethylene or polypropylene. Polypropylene has high heat resistance as well as high strength and rigidity. The sealing structure 30 is made of polypropylene material, which can not only ensure the structural strength of the sealing structure 30, but also ensure that the heat generated by the core during normal charging and discharging will not have a significant impact on the sealing structure 30. Polyethylene has high flexibility, ductility and a high melting point. The sealing structure 30 is made of polyethylene material, which makes the sealing structure 30 have high flexibility and ductility, and at the same time has a high melting point, ensuring that the heat generated by the core during normal charging and discharging will not have a significant impact on the sealing structure 30.

[0048] In one embodiment of the present invention, the thickness of the sealing structure 30 ranges from 5 μm to 20 μm.

[0049] Through the above arrangement, while ensuring the sealing effect of the sealing structure 30 on the accommodating cavity 13, the weight of the protective body 10 can be reduced and the cost can be saved.

[0050] The utility model also provides a battery pack, comprising: an outer shell; a winding core, the winding core is installed in the outer shell; and the above-mentioned protective structure, the protective structure is coated on the outer periphery of the winding core.

[0051] In this embodiment, the protection structure of the battery pack has all the technical solutions and all the technical effects of the above-mentioned protection structure, which will not be repeated here.

[0052] From the above description, it can be seen that the above-mentioned embodiments of the utility model achieve the following technical effects: the protective body is wrapped around the outer periphery of the core, and when the temperature of the core is too high, the filler decomposes, and the decomposition process absorbs heat and can absorb part of the heat. At the same time, the filler decomposes to produce non-combustible gas, which can reduce the oxygen concentration inside the core. The non-combustible gas is discharged from the accommodating cavity, and the discharge of the non-combustible gas can quickly take away the heat and reduce the temperature of the core. After the filler in the accommodating cavity decomposes, the protective body is a hollow structure, which can also delay the transfer of heat from the external environment to the inside of the core. Through the above-mentioned settings, it is possible to prevent the temperature inside the core from continuing to rise and the occurrence of side reactions, and avoid thermal runaway of the core.

[0053] Obviously, the embodiments described above are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0054] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0055] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A protective structure, It is characterized in that include: A protective body (10), wherein the protective body (10) is configured to be wrapped around the outer periphery of the winding core, the protective body (10) includes a plurality of accommodating cavities (13), at least some of the accommodating cavities (13) are provided with fillers (20), the fillers (20) are configured to decompose at a preset temperature and generate non-flammable gas, and the non-flammable gas can be discharged from the accommodating cavities (13), and the preset temperature is greater than the maximum working temperature of the winding core and lower than the auto-ignition temperature of the winding core.

2. The protective structure according to claim 1, It is characterized in that The protective body (10) comprises a first concave-convex protective body (11), the first concave-convex protective body (11) is a wave-shaped structure, the first concave-convex protective body (11) comprises a plurality of first convex portions (111) and a plurality of first concave portions (112), the plurality of first convex portions (111) and the plurality of first concave portions (112) are alternately arranged along a first direction, and each of the first convex portions (111) can form the accommodating cavity (13); and / or the filler (20) is one or more of ammonium bicarbonate, sodium bicarbonate, potassium bicarbonate, and ammonium chloride.

3. The protective structure according to claim 2, It is characterized in that The protective body (10) further comprises a second concave-convex protective body (12), the second concave-convex protective body (12) being a wave-shaped structure, the second concave-convex protective body (12) comprising a plurality of second convex portions (121) and a plurality of second concave portions (122), the plurality of second convex portions (121) and the plurality of second concave portions (122) being alternately arranged along the first direction, each second convex portion (121) being capable of forming the accommodating cavity (13), the plurality of first convex portions (111) and the plurality of second convex portions (121) being arranged in one-to-one correspondence, the plurality of first concave portions (112) and the plurality of second concave portions (122) being arranged in one-to-one correspondence, and the correspondingly arranged first concave portions (112) and the second concave portions (122) forming the accommodating cavity (13).

4. The protective structure according to claim 1, It is characterized in that The protective body (10) further comprises a corrugated paper structure, wherein the corrugated paper structure comprises a wavy installation body (14) and a connecting structure (17), wherein the connecting structure (17) is arranged on one side of the wavy installation body (14) and surrounds a plurality of the accommodating cavities (13) with the wavy installation body (14).

5. The protective structure according to claim 4, It is characterized in that The wavy installation body (14) comprises a plurality of wave crests (15) and a plurality of wave troughs (16), and the plurality of wave crests (15) and the plurality of wave troughs (16) are alternately arranged along a first direction. The number of the corrugated paper structures is two, and the wavy installation bodies (14) of the two corrugated paper structures are arranged opposite to each other. The plurality of wave crests (15) of the two wavy installation bodies (14) are arranged one-to-one, and the plurality of wave troughs (16) of the two wavy installation bodies (14) are arranged one-to-one, and the two correspondingly arranged wave crests (15) are bonded and fixed, and the two correspondingly arranged wave troughs (16) form the accommodating cavity (13).

6. The protective structure according to any one of claims 1 to 5, It is characterized in that The volume occupied by the filler (20) is less than or equal to 30% of the volume of the accommodating cavity (13).

7. The protective structure according to claim 2 or 3, It is characterized in that The protective body (10) further comprises a sealing structure (30), wherein the sealing structure (30) is coated on the outer periphery of the protective body (10) so as to seal the accommodating cavity (13).

8. The protective structure according to claim 7, It is characterized in that The sealing structure (30) is made of polyethylene or polypropylene material.

9. The protective structure according to claim 7, It is characterized in that The thickness of the sealing structure (30) ranges from 5 μm to 20 μm.

10. A battery pack, It is characterized in that include: shell; A winding core, the winding core being installed in the housing; as well as The protective structure according to any one of claims 1 to 9, wherein the protective structure is wrapped around the outer periphery of the winding core.

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