Battery top cover assembly and secondary battery

Abstract

The utility model provides a battery top cover assembly and a secondary battery, and relates to the technical field of battery manufacturing. The battery top cover assembly comprises a top cover plate, an anti-explosion valve, a first protective cover and a second protective cover, the top cover plate is provided with an anti-explosion valve hole communicated with the inner side and the outer side. The anti-explosion valve is installed in the anti-explosion valve hole, the first protective cover is installed on the side, close to the outer side, of the anti-explosion valve, and the second protective cover is installed on the side, close to the inner side, of the anti-explosion valve. And meanwhile, the section size of the first through hole in the first protective cover is smaller than that of the second through hole in the second protective cover. The first protective cover and the second protective cover are respectively arranged on the inner side and the outer side of the anti-explosion valve, so that a larger second through hole in the second protective cover can meet the requirement of quickly discharging gas and heat in the battery, meanwhile, larger high-temperature particles are blocked, and smaller high-temperature particles are blocked by the first protective cover; therefore, most of high-temperature particulate matters can be prevented from being discharged under the condition that gas and heat are not prevented from being quickly discharged from the inside of the battery.

Description

Technical Field

[0001] The utility model relates to the technical field of battery manufacturing, in particular to a battery top cover assembly and a secondary battery. Background Art

[0002] Environmental and energy issues are global issues that concern human survival and development. Lithium-ion batteries are the new electrochemical energy with the greatest commercial value and are being widely used in new energy vehicles and energy storage. As people's demand for the range of new energy vehicles and the power of energy storage power stations continues to increase, the capacity, energy density and voltage of single cells are also increasing, which brings with it an increase in potential safety hazards of batteries. Therefore, how to ensure the safety of batteries while improving their energy density and electrical performance is a pain point and research hotspot in the industry.

[0003] At present, an explosion-proof valve is generally installed on the top cover of the battery. The principle of the explosion-proof valve is that when thermal runaway occurs inside the battery, gas and heat are generated, which increases the internal pressure of the battery. When the internal pressure of the battery is greater than the explosion threshold of the explosion-proof valve, the explosion-proof valve breaks toward the outside of the battery to release pressure and discharge the gas and heat generated inside the battery, thereby playing an explosion-proof role. However, when thermal runaway occurs inside the battery and causes the explosion-proof valve to break, the explosion-proof valve will not only discharge the gas and heat generated inside the battery, but also the flammable electrolyte and high-temperature particulate matter. After contacting with oxygen in the air outside the battery, the flammable electrolyte and flammable gas will ignite, causing the battery to catch fire. Therefore, currently a protective cover is provided on the inside of the explosion-proof valve for protection. However, if the through hole on the protective cover is large, although it can ensure that gas and heat can be quickly discharged when the battery valve ruptures, it can only block some larger high-temperature particles, but cannot effectively block the discharge of some smaller high-temperature particles, and there is still a certain fire risk. If the through hole on the protective cover is small, although it can effectively block the discharge of smaller high-temperature particles, it is not conducive to the rapid discharge of gas and heat when the battery valve ruptures, which is not conducive to the safety performance of the battery. Utility Model Content

[0004] The purpose of the utility model is to provide a battery top cover assembly, which can improve the technical problem of low safety performance in the prior art.

[0005] The utility model also aims to provide a secondary battery, which can improve the technical problem of low safety performance in the prior art.

[0006] The embodiments of the present invention can be implemented in the following ways:

[0007] A battery top cover assembly, the battery top cover assembly comprising:

[0008] A top cover plate, wherein the top cover plate has an inner side and an outer side opposite to each other, and an explosion-proof valve hole is provided on the top cover plate, wherein the explosion-proof valve hole communicates with the inner side and the outer side;

[0009] an explosion-proof valve installed in the explosion-proof valve hole; and

[0010] A first protective cover and a second protective cover, wherein the first protective cover and the second protective cover are respectively installed on both sides of the explosion-proof valve, and the first protective cover is located on the side of the explosion-proof valve close to the outer side, and the second protective cover is located on the side of the explosion-proof valve close to the inner side; a first through hole is arranged on the first protective cover, and a second through hole is arranged on the second protective cover, and a cross-sectional size of the first through hole is smaller than a cross-sectional size of the second through hole.

[0011] Optionally, a protruding structure is provided on the top cover plate, the protruding structure is located on the outer side, and the protruding structure is arranged around the explosion-proof valve hole; the first protective cover is provided with a flange, and the flange is sleeved outside the protruding structure.

[0012] Optionally, the inner circumferential surface of the flange has a draft angle, and the angle of the draft angle is θ, 45°≤θ≤90°.

[0013] Optionally, the battery top cover assembly further includes a pole mounted on the top cover plate, and a height of the protruding structure is less than or equal to a height of the pole on the outer side.

[0014] Optionally, the first through hole forms a first opening and a second opening on both sides of the first shield; the opening size of the first opening is larger or smaller than the opening size of the second opening.

[0015] Optionally, a longitudinal section of the first through hole is in a frustum shape.

[0016] Optionally, the size of the first through hole is 50 mesh to 200 mesh.

[0017] Optionally, the first shield is welded and fixed on the top cover plate.

[0018] Optionally, the first shield is snap-fitted and fixed on the top cover plate.

[0019] A secondary battery comprises the battery top cover assembly as described above.

[0020] The battery top cover assembly and the secondary battery provided by the embodiments of the utility model have the following beneficial effects:

[0021] The embodiment of the utility model provides a battery top cover assembly, which includes a top cover plate, an explosion-proof valve, a first shield and a second shield. The top cover plate has an inner side and an outer side opposite to each other, and an explosion-proof valve hole connecting the inner side and the outer side is provided on the top cover plate. The explosion-proof valve is installed in the explosion-proof valve hole, and the first shield is installed on the side of the explosion-proof valve close to the outer side, and the second shield is installed on the side of the explosion-proof valve close to the inner side. At the same time, a first through hole is provided on the first shield, and a second through hole is provided on the second shield, and the cross-sectional size of the first through hole is smaller than the cross-sectional size of the second through hole. By respectively providing the first shield and the second shield on the inner and outer sides of the explosion-proof valve, the larger second through hole on the second shield can meet the requirement that the gas and heat inside the battery are quickly discharged in the case of a battery valve rupture, and at the same time, a larger part of the high-temperature particles are blocked, and the smaller high-temperature particles that pass through the second shield smoothly are blocked by the first shield, thereby helping to block the discharge of most of the high-temperature particles without hindering the rapid discharge of gas and heat from the inside of the battery, and helping to improve safety performance.

[0022] The embodiment of the utility model also provides a secondary battery, which includes the battery top cover assembly. Since the secondary battery includes the battery top cover assembly, it also has the beneficial effect of blocking most of the high-temperature particles from being discharged without hindering the rapid discharge of gas and heat from the inside of the battery, which helps to improve safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0024] Figure 1 A schematic structural diagram of a battery top cover assembly provided according to one aspect of the utility model is shown;

[0025] Figure 2 A cross-sectional view of a battery top cover assembly provided according to one aspect of the utility model is shown;

[0026] Figure 3 A schematic diagram of the structure of a first shield after explosion in a battery top cover assembly provided according to one aspect of the utility model is shown;

[0027] Figure 4 A diagram showing a connection structure between a first shield and a top cover plate provided according to one aspect of the utility model is shown;

[0028] Figure 5 A schematic cross-sectional structure diagram of a first shield in a battery top cover assembly provided according to one aspect of the utility model is shown;

[0029] Figure 6 A diagram showing a connection structure between a first shield and a top cover plate provided according to another aspect of the utility model is shown;

[0030] Figure 7 A schematic cross-sectional structure diagram of a first shield in a battery top cover assembly provided according to another aspect of the utility model is shown.

[0031] Reference numerals:

[0032] 100-battery top cover assembly; 110-top cover plate; 111-upper side; 112-lower side; 113-explosion-proof valve hole; 114-raised structure; 115-first clamping part; 120-first protective cover; 121-flange; 122-first through hole; 123-first opening; 124-second opening; 125-second clamping part; 130-explosion-proof valve; 140-pole; 141-positive pole; 142-negative pole. DETAILED DESCRIPTION

[0033] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are only exemplary and should not be construed as limiting the scope of protection of the present invention.

[0034] In the description of the present utility model, it should be noted that if the terms "upper", "lower", "inside", "outside", "vertical" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the utility model product is usually placed when used, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model.

[0035] At the same time, it should be noted that the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified or limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, an integral connection, or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or the internal communication of two components, etc. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] Figure 1 This is a schematic diagram of the structure of the battery top cover assembly 100 provided in this embodiment. Figure 2 A cross-sectional view of the battery top cover assembly 100 provided in this embodiment, Figure 3 This is a schematic diagram of the structure of the first shield 120 in the battery top cover assembly 100 provided in this embodiment after explosion. Figure 4 for Figure 2 The enlarged schematic diagram of the local structure at A in the middle. Please refer to Figure 1-Figure 4 This embodiment provides a battery top cover assembly 100, and also provides a secondary battery (not shown).

[0038] The secondary battery includes a battery top cover assembly 100, and the secondary battery also includes a core pack (not shown) and a shell (not shown). The shell can be set as a box structure with an opening on one side. The battery top cover assembly 100 is installed at the opening of the shell, so as to form a closed battery cavity with the shell, and the core pack is installed in the battery cavity. In the description of this embodiment, the "inside" of the top cover plate 110 is the side of the top cover plate 110 located in the battery cavity, and the outside of the top cover plate 110 is the side of the top cover plate 110 that is away from the battery cavity and is located in the external environment.

[0039] The battery top cover assembly 100 includes a top cover plate 110, an explosion-proof valve 130, a first protective cover 120 and a second protective cover. The top cover plate 110 has an inner side and an outer side opposite to each other, and an explosion-proof valve hole 113 connecting the inner side and the outer side is provided on the top cover plate 110. The explosion-proof valve 130 is installed in the explosion-proof valve hole 113, and the first protective cover 120 is installed on the side of the explosion-proof valve 130 close to the outer side, and the second protective cover is installed on the side of the explosion-proof valve 130 close to the inner side. At the same time, a first through hole 122 is provided on the first protective cover 120, and a second through hole is provided on the second protective cover, and the cross-sectional size of the first through hole 122 is smaller than the cross-sectional size of the second through hole. By arranging the first protective cover 120 and the second protective cover on the inner and outer sides of the explosion-proof valve 130 respectively, the larger second through hole on the second protective cover can meet the requirement of rapid discharge of gas and heat inside the battery when the battery valve is broken, and at the same time block some larger high-temperature particles, and the small high-temperature particles that pass through the second protective cover smoothly are blocked by the first protective cover 120, thereby helping to block the discharge of most high-temperature particles without hindering the rapid discharge of gas and heat from the inside of the battery, thereby helping to improve safety performance.

[0040] The battery top cover assembly 100 provided in this embodiment is further described below:

[0041] Please continue to refer to Figure 1-Figure 4In this embodiment, the top cover plate 110 is a roughly square plate-shaped member, and its two side surfaces along the thickness direction are respectively an upper side surface 111 and a lower side surface 112. When the top cover plate 110 is installed on the housing, the lower side surface 112 is used to form a battery cavity, and the upper side surface 111 is located outside the battery cavity. Therefore, the upper side surface 111 can also be regarded as a side surface of the top cover plate 110 located on the outside, and the lower side surface 112 can also be regarded as a side surface of the top cover plate 110 located on the inside. The explosion-proof valve hole 113 passes through the upper side surface 111 and the lower side surface, thereby forming openings on the upper side surface 111 and the lower side surface 112 respectively. The first protective cover 120 is installed at the explosion-proof valve hole 113 and covers the opening formed by the explosion-proof valve hole 113 on the upper side 111, that is, the gas entering the explosion-proof valve hole 113 can only be discharged through the first through hole 122 on the first protective cover 120; similarly, the second protective cover covers the opening formed by the explosion-proof valve hole 113 on the lower side 112, that is, the gas generated in the battery cavity and some smaller high-temperature particles can only enter the explosion-proof valve hole 113 through the second through hole on the second protective cover.

[0042] It should be noted that the structure of the second protective shield is not illustrated in this embodiment. It can be understood that the second protective shield can be set to a structure with substantially the same structure as the first protective shield 120 but a different through hole size. Alternatively, in some other embodiments, the protective shield structure installed on the inner side of the explosion-proof valve hole 113 in the prior art can be used as the second protective shield.

[0043] Figure 5 The cross-sectional structure diagram of the first shield 120 in the battery top cover assembly 100 provided in this embodiment is shown. Figure 1-Figure 5 Optionally, a protruding structure 114 is provided on the top cover plate 110, and the protruding structure 114 is located on the outside, that is, the protruding structure 114 can be regarded as the upper side surface 111 protruding upward, and the protruding structure 114 is arranged around the explosion-proof valve hole 113. The first protective cover 120 is provided with a flange 121, and the flange 121 is sleeved outside the protruding structure 114, so that the first protective cover 120 covers the channel surrounded by the protruding structure 114, thereby achieving the sealing of the explosion-proof valve hole 113.

[0044] Furthermore, the battery top cover assembly 100 also includes a pole 140 installed on the top cover plate 110, and the height of the protruding structure 114 is less than or equal to the height of the pole 140 on the outside to prevent the setting of the protruding structure 114 from affecting the assembly.

[0045] Specifically, the top cover plate 110 is also provided with a pole hole, the pole 140 is installed in the pole hole, and one end of the pole 140 protrudes from the lower side 112 and is located on the inner side to be electrically connected to the core pack in the battery cavity, and the other end of the pole 140 protrudes from the upper side 111 and is located on the outer side to be electrically connected to the outside, so as to extract the electricity stored in the core pack. The height of the pole 140 on the outer side mentioned here can be regarded as the height of the pole 140 protruding from the upper side 111. Generally, the pole 140 includes a positive pole 141140 and a negative pole 142140. Accordingly, the pole hole opened on the top cover plate 110 includes a positive pole hole and a negative pole hole, and the positive pole hole and the negative pole hole are located on both sides of the explosion-proof valve hole 113.

[0046] Further, the inner circumference of the flange 121 has a draft angle, that is, the inner circumference of the flange 121 is a tapered surface. The angle of the draft angle is θ, 45°≤θ≤90°. Optionally, the draft angle θ can be set to 45°, 75° or 90°.

[0047] In this embodiment, the first shield 120 is fixedly connected to the top cover plate 110. Optionally, the first shield 120 and the top cover plate 110 may be connected by welding, that is, the first shield 120 is fixed to the top cover plate 110 by welding.

[0048] Specifically, the first shield 120 is welded to the protruding structure 114, that is, the welded portion between the protruding structure 114 and the first shield 120 can be regarded as a welding portion. It can be understood that in some other embodiments, other methods can also be used to achieve the connection between the first shield 120 and the top cover plate 110. As an example, Figure 6 Another connection structure diagram of the first shield 120 and the top cover plate 110 is shown, as shown in FIG. Figure 6 The first shield 120 is fixedly connected to the top cover plate 110 by clamping. Specifically, the protruding structure 114 is provided with a first clamping portion 115, and the flange 121 of the first shield 120 is provided with a second clamping portion 125. When the first shield 120 is covered on the protruding structure 114, the first shield 120 is fixedly installed on the top cover plate 110 by the clamping cooperation of the first clamping portion 115 and the second clamping portion 125. Alternatively, the first shield 120 can also be fixed to the top cover plate 110 by the combined action of welding and clamping.

[0049] The first shield 120 is provided with a plurality of first through holes 122, which penetrate the first shield 120, thereby forming a first opening 123 and a second opening 124 on both sides of the first shield 120. In this embodiment, the first shield 120 is arranged outside the explosion-proof valve 130. In the case of a battery valve rupture, high-temperature gas and smaller high-temperature particles enter the explosion-proof valve hole 113 through the second shield. The first shield 120 needs to block the smaller high-temperature particles from entering the outside while ensuring smooth passage of the high-temperature gas. Therefore, the opening size of the first opening 123 can be set to be larger than the opening size of the second opening 124 (such as Figure 5 Alternatively, the opening size of the first opening 123 may be set to be smaller than the opening size of the second opening 124 (as shown in FIG. Figure 7 As shown), that is, the openings at both ends of the first through hole 122 have different sizes, so that smaller high-temperature particles entering the explosion-proof valve hole 113 can be blocked by the small-sized opening, and the smooth discharge of gas can be ensured by having a larger opening.

[0050] Furthermore, the longitudinal section of the first through hole 122 is in the shape of a frustum, that is, the flow area of ​​the first through hole 122 changes uniformly from the first opening 123 to the second opening 124. Specifically, when the first through hole 122 is configured as follows Figure 5 In the structure shown in FIG. 1 , the first opening 123 is large and the second opening 124 is small. Then, the flow area of ​​the first through hole 122 decreases from the first opening 123 to the second opening 124. When the first through hole 122 is configured as follows Figure 6 In the structure shown, the first opening 123 is small and the second opening 124 is large, and the flow area of ​​the first through hole 122 increases from the first opening 123 to the second opening 124. Optionally, the inclination angle of the longitudinal section of the first through hole 122 can be set to 45° to 135°, and when the longitudinal section of the first through hole 122 is in the shape of a truncated cone, the inclination angle of the longitudinal section of the first through hole 122 should not be set to 90°.

[0051] Optionally, the size of the first through hole 122 is 50 mesh to 200 mesh. Specifically, the opening size of the larger end of the first through hole 122 should be less than or equal to 200 mesh, and the opening size of the smaller end of the first through hole 122 should be greater than or equal to 50 mesh. Figure 5 In the structure of the first through hole 122 shown, the size of the first opening 123 is set to 200 meshes, and the size of the second opening 124 is set to 50 meshes, or the size of the first opening 123 is set to 150 meshes, and the size of the second opening 124 is set to 100 meshes.

[0052] The battery top cover assembly 100 and the secondary battery provided by the embodiment of the utility model are provided with a first shield 120 and a second shield respectively on both sides of the explosion-proof valve 130, and the size of the first through hole 122 on the first shield 120 is set to be smaller than the size of the second through hole on the second shield, so that the larger second through hole on the second shield can meet the requirement of rapid discharge of gas and heat inside the battery in the case of battery valve rupture, and at the same time block the larger part of high-temperature particles, and the smaller high-temperature particles that pass through the second shield smoothly are blocked by the first shield 120, thereby helping to block the discharge of most of the high-temperature particles without hindering the rapid discharge of gas and heat from the inside of the battery, and helping to improve safety performance. At the same time, setting the first through hole 122 to a structure with a large opening at one end and a small opening at the other end helps to further capture high-temperature particles while guiding the gas flow direction to prevent overflow.

[0053] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technology in this field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention.

Claims

1. A battery top cover assembly, characterized in that: The battery top cover assembly comprises: A top cover plate, wherein the top cover plate has an inner side and an outer side opposite to each other, and an explosion-proof valve hole is provided on the top cover plate, wherein the explosion-proof valve hole communicates with the inner side and the outer side; an explosion-proof valve installed in the explosion-proof valve hole; and A first protective cover and a second protective cover, wherein the first protective cover and the second protective cover are respectively installed on both sides of the explosion-proof valve, and the first protective cover is located on the side of the explosion-proof valve close to the outer side, and the second protective cover is located on the side of the explosion-proof valve close to the inner side; a first through hole is arranged on the first protective cover, and a second through hole is arranged on the second protective cover, and a cross-sectional size of the first through hole is smaller than a cross-sectional size of the second through hole.

2. The battery top cover assembly according to claim 1, characterized in that: The top cover plate is provided with a protruding structure, the protruding structure is located at the outer side, and the protruding structure is arranged around the explosion-proof valve hole; the first protective cover is provided with a flange, and the flange is sleeved outside the protruding structure.

3. The battery top cover assembly according to claim 2, characterized in that: The inner peripheral surface of the flange has a draft angle, and the angle of the draft angle is θ, 45°≤θ≤90°.

4. The battery top cover assembly according to claim 2, characterized in that: The battery top cover assembly also includes a pole installed on the top cover plate, and the height of the protruding structure is less than or equal to the height of the pole on the outer side.

5. The battery top cover assembly according to claim 1, characterized in that: The first through hole forms a first opening and a second opening on both sides of the first shield; the opening size of the first opening is larger or smaller than the opening size of the second opening.

6. The battery top cover assembly according to claim 5, characterized in that: The longitudinal section of the first through hole is in a frustum shape.

7. The battery top cover assembly according to claim 1, characterized in that: The size of the first through hole is 50 mesh to 200 mesh.

8. The battery top cover assembly according to claim 1, characterized in that: The first shield is welded and fixed on the top cover plate.

9. The battery top cover assembly according to claim 1, characterized in that: The first shield is clamped and fixed on the top cover plate.

10. A secondary battery, characterized in that: The secondary battery comprises the battery top cover assembly as described in any one of claims 1-9.

Images