Seal, battery cap and battery

Abstract

A seal designed for insulating sealing of a gap between a cap (2) and a housing (3) of a battery, comprising a body (1) which includes a first sub-body (11) located between the housing (3) and the cap (2); wherein the melting point of at least a part of the first sub-body (11) is greater than the temperature in the enclosed space of the housing (3) when the battery is in its maximum discharge state.

Description

TECHNICAL FIELDThe present application relates to the technical field of batteries, specifically a gasket, a battery cap, and a battery.PRIOR ARTIn related technologies, a seal ring is used to seal the space between a steel case and a cap of a battery, which results in the internal temperature of the battery being too high during the high power discharge process of the battery.DISCLOSURE OF THE INVENTIONA high internal temperature of the battery causes the part of the sealing ring located between the steel housing and the cap of the battery to melt. On the basis of this, the part of the steel case and the cap of the battery are in direct contact, which leads to the risk of a short circuit in the battery.According to a first aspect, the present application provides a gasket configured to insulatively seal a gap between a cap and a case of a battery, and comprising a body including a first sub-body located between the case and the cap; wherein the melting point of at least a part of the first sub-body is higher than the temperature in the closed space of the case when the battery is in the maximum discharge state.In a second aspect, the present application provides a battery cap including a seal.In a third aspect, the present application provides a battery comprising a battery cap.Advantageous Effects:In the embodiment of the present application, by making the melting point of at least a part of the first sub-body higher than the temperature in the closed space of the case when the battery is in the maximum discharge state, that is, the first sub-body does not melt or partially melt when the battery is in the maximum discharge state, and thus the cap and the case can still be separated from each other by the first sub-body when the battery is in the maximum discharge state, the problem of the short circuit in the battery due to contact between the case and the cap is avoided.SUMMARY OF THE INVENTIONFIG. 1 is a schematic diagram of the assembly of the sealing ring of PBT in related technology; FIG. 2 is a schematic structural diagram of melting in FIG. 1 at the surface temperature of the battery in the range of A; FIG. 3 is a schematic diagram showing the structure of the gasket of the present application at the surface temperature of the battery in the A range; FIG. 4 is a schematic diagram showing the structure of the gasket provided in the present application; FIG. 5 is a schematic sectional diagram of the battery cap provided in the present application; FIG. 6 is a schematic sectional diagram of the battery provided in this application.Description of the Reference Numerals100. Seal; 1. body; 11. first sub-body; 12. second sub-body; 2. cap; 2A. first side; 3. housing.EMBODIMENTS OF THE INVENTIONIn the present application, the terms "connected to each other", "connecting", "fastening" or the like are intended to be understood in the broader sense unless expressly stated otherwise. Thus, for example, this can be a fixed, a releasable or a one-piece connection as well as a mechanical and also an electrical connection. In addition, direct connections, indirect connections or connections produced via an intermediate piece, as well as internal connections of two elements or interactions of two elements are also conceivable. One of ordinary skill in the art can be based on the subject to determine what meaning the terms mentioned according to the present application are intended to have.In the present invention, a first feature disposed "above" or "below" a second feature may be, unless expressly stated and defined otherwise, the case where the first feature directly contacts the second feature or the first and second features are in contact without direct contact via another feature interposed therebetween. Moreover, in the case of the first feature, which is arranged "on", "above" the second feature and "above" the second feature, it may be the case, inter alia, that the first feature lies directly above and obliquely above the second feature, or that the horizontal height position of the first feature is higher than that of the second feature. In the case of the first feature, which is arranged "under" the second feature and "below" the second feature, it may be the case, inter alia, that the first feature lies directly under and obliquely under the second feature, or that the horizontal height position of the first feature lies lower than that of the second feature.In the description of the present embodiment, the terms "upper", "lower", "left", "right", "front", "rear", etc. are used with reference to the illustrated orientation or positional relationship in each figure to describe only the operation and facilitate the description as appropriate. In other words, these terms are used to indicate neither in-depth nor explicitly the positioning and the configuration and operation of the relevant device or of the relevant element in a predetermined positioning, and therefore there is also no restriction of the application here. Moreover, the terms "first" and "second" having no particular meaning are used only to achieve distinction in the description.The present application provides a gasket, a battery cap and a battery, and FIGS. 1 to 6 show some embodiments of the present application.Reference is made to FIGS. 3 to 6. In some embodiments of the application, the gasket 100 is configured to insulatively seal a gap between a cap 2 and a case 3 of a battery. The gasket 100 comprises a body 1 comprising a first sub-body 11 located between the case 3 and the cap 2; wherein the melting point of at least a part of the first sub-body 11 is higher than the temperature in the closed space of the case 3 when the battery is in the maximum discharge state.In the embodiment of the present application, by making the melting point of at least a part of the first sub-body 11 higher than the temperature in the closed space of the case 3 when the battery is in the maximum discharge state, that is, the first sub-body 11 does not melt or partially melt when the battery is in the maximum discharge state, and thus the cap 2 and the case 3 can still be separated from each other by the first sub-body 11 when the battery is in the maximum discharge state, the problem of the short circuit in the battery due to contact between the case 3 and the cap 2 is avoided.It should be added that since the heat generated inside the case 3 of the battery and near the end of the battery is the greatest in the actual application of the battery, the melting point of at least a part of the first sub-body 11 is higher than the temperature in the closed space of the case 3 when the battery is in the maximum discharge state; In the case where the temperature in the closed space of the case 3 also includes the space portion where the end portion of the battery is enclosed by the case 3, it is necessary to avoid melting of the gasket 100 interposed between the case 3 and the cap 2 and to cause direct contact between the case 3 and the cap 2 to cause direct contact between the case 3 of the battery and the cap 2, i.e., the heat resistance of the gasket 100 interposed between the case 3 and the cap 2 of the battery must be improved, so that the first sub-body 11 having a melting point higher than the temperature in the closed space of the case 3 when the battery is in the maximum discharge state is provided.In some embodiments of the application, the cap 2 further includes a first side 2A facing the housing 3 in the axial direction of the housing 3, and the melting point of at least the part of the first sub-body 11 located between the first side 2A and the housing 3 is higher than the temperature in the closed space of the housing 3 when the battery is in the maximum discharge state. That is, in this embodiment, since the part of the first sub-bodies 11 located between the first side 2A and the case 3 tends to melt when the battery is in the maximum discharge state, it is necessary to ensure that the first sub-body 11 located between the first side 2A and the case 3 does not melt or partially melts when the battery is in the maximum discharge state, in order to avoid the short circuit of the battery caused by the contact between the case 3 and the cap 2.Note that the seal ring between the battery steel case and the cap in related technology is made of polybutylene terephthalate; in some embodiments of the present application, the surface temperature of the case 3 is detected when the battery is in the maximum discharge state, and the surface temperature of the case 3 is measured as A; Here, A satisfies 120°C≤A≤140°C See FIGS. 1 to 2, i.e., when the surface temperature of the case 3 is in the range of 120° C.≤A≤140, the battery seal ring made of polybutylene terephthalate in the related technology melts at the position of the corresponding battery case 3 and the cap 2. The melting point of the first sub-body 11 in the embodiment of the present application is higher than the temperature in the closed space of the case 3 when the battery is in the maximum discharge state, i.e., the melting point of at least a part of the first sub-bodies 11 is higher than the melting point of polybutylene terephthalate. When the battery is in the maximum discharge state, it does not melt or only partially melts to avoid direct contact between the housing 3 and the cap and to cause a short circuit of the battery.The material of the first sub-body 11 comprises at least one of soluble polytetrafluoroethylene and polyphenylene sulfide. That is, in one embodiment, the material of the first sub-body 11 is soluble polytetrafluoroethylene (PFA); in another embodiment, the material of the first sub-body 11 is polyphenylene sulfide (PPS); in another embodiment, the material of the first sub-body 11 may also be soluble polytetrafluoroalkoxy (PFA) mixed with polyphenylene sulfide (PPS). When the battery is discharged with high power, the first sub-body 11 located between the case 3 and the cap 2 of the battery does not melt or only partially melts to avoid contact between the case 3 of the battery and the cap 2 and cause a short circuit of the battery.It should be noted that the melting point of soluble polytetrafluoroalkoxy (PFA) is between 290° C. and 312° C., the melting point of polyphenylene sulfide (PPS) is between 280° C. and 290° C., and the melting point of polybutylephthalate (PBT) is between 220° C. and 230° C. The melting points of soluble PTFE and polyphenylene sulfide are higher than that of polybutylene terephthalate to avoid the risk of melting the first lower body 11 when the battery is discharged with high power.The temperature of the enclosed space inside the housings 3 is positively correlated with the surface temperature of the housings 3, i.e., the temperature of the enclosed space inside the housings 3 rises and the surface temperature of the housings 3 also rises. In order to assist the experiment personnel in performing tests, in the embodiments of the present application, the temperature change in the inner space of the housing 3 is detected by measuring the surface temperature of the housing 3. Further, the state of the seal ring disposed between the cap 2 and the housing 3 is checked. A temperature detection device is used to detect the surface temperature of the battery. In an embodiment of the present application, the temperature sensing device includes a temperature sensing wire.It will be understood that when the battery is in the maximum discharge state, the surface temperature of the measured housings 3 is between 120° C. and 140° C., and the value of the inner housing temperature B of the housings 3 is between 220° C. and 280° C., i.e., when the battery is in the maximum discharge state, the inner housing temperature of the housing 3 is higher than the melting point of polybutylene terephthalate, which may lead to melting of the seal ring of polybutylene terephthalate in related technologies. The inner casing temperature of the casing 3 is lower than the melting point of soluble PTFE and polyphenylene sulfide, i.e., the first sub-body 11 made of at least one of soluble PTFE and polyphenylene sulfide in the present application is not melted.In some embodiments of the application, the first sub-body 11 has a first state in which the surface temperature of the housing 3 is lower than the A range and a second state in which the surface temperature of the housings 3 is in the A range; wherein the thickness of the first sub-body between the housing 3 and the cap 2 when the first sub-body 11 is in the first state is defined as D 1, and the thickness of the first sub-body between the housing 3 and the cap 2 when the first sub-body 11 is in the second state is defined as D 2; wherein D 1 and D 2 satisfy: D 2≥0.8D 1. That is, when the first sub-body 11 uses at least one of soluble polytetrafluoroethylene and polyphenylene sulfide as its main components and the first sub-body 11 is entirely made of soluble polytetrafluoroethylene or polyphenylene sulfide, the first sub-body 11 is not melted, that is, D2 is D1; When the first sub-body 11 is partly made of soluble polytetrafluoroethylene or polyphenylene sulfide, the first sub-body 11 is partly melted to ensure that the thickness of the first sub-body 11 after melting is still greater than 80% of the original thickness to maintain a sufficient safety margin between the case 3 and the cap 2 of the battery.Reference is made to FIG. 5. The body 1 further comprises a second sub-body 12 connected to the first sub-body 11, and the material of the second sub-body 12 is identical or not identical to the material of the first sub-body 11. At this time, the first sub-body 11 does not melt such that direct contact is caused between the case 3 of the battery and the cap 2 when the battery is in a high-power discharge state, i.e., in a high-temperature state, and the materials of other parts of the body 1 are not limited in this embodiment, and the body 1 further includes a second sub-body 12, and the first sub-body 11 may be connected to the second sub-body 12, that is, the first sub-body 11 and the second sub-body 12 are integrally formed. The material of the second sub-body 12 is not limited, and the melting point of the second sub-body 12 may be higher than the melting point of the first sub-body 11, or the melting point of the second sub-body 12 is equal to the melting point of the first sub-body 11, or the melting point of the second sub-body 12 is lower than the melting point of the first sub-body 11.In some embodiments of the application, the material of the second sub-body 12 includes at least one of soluble polytetrafluoroethylene, polyphenylene sulfide, and polybutylene terephthalate. That is, provided that the material of the first sub-body 11 is at least one of soluble polytetrafluoroethylene and polyphenylene sulfide, the material of the second sub-body 12 may be at least one of soluble polytetrafluoroethylene, polyphenylene sulfide and polybutylene terephthalate, or a mixture of at least two of them.In an embodiment of the present application, when the material of the second sub-body 12 is polybutylene terephthalate, the roughness of the first sub-body 11 is larger than that of the second sub-body 12, and when the material of the first sub-body 11 is at least one of soluble polytetrafluoroethylene and polyphenylene sulfide, the surface of the main body 1 needs to be coated with adhesive, and when the material of the first sub-body 11 is at least one of soluble polytetrafluoroethylene and polyphenylene sulfide, the adhesive is not easily adhered to the first sub-body 11 because it has the same material as the first sub-body 11, so that the surface of the first sub-body 11 needs to be treated to increase the roughness of the surface of the first sub-body 11 and thus improve the adsorption force of the surface of the first sub-body 11 for the adhesive. It is understood that the roughness of the first sub-body 11 is larger than that of the second sub-body 12, so that the adhesive can easily adhere to the surface of the body 1.Moreover, in an embodiment of the present application, the body 1 is formed hollow and ring-shaped, and the body 1 is arranged to be properly installed in the case 3 of the battery, and the body 1 has an internal cavity for installing the cap 2, an explosion-proof plate, and other parts.The application further provides a battery cap, the battery cap includes a gasket 100, and the gasket 100 is as described above, because the battery cap adopts all the technical solutions of all the above-mentioned embodiments, it has at least the advantageous effects caused by the technical solutions of the above embodiments, and repetition is omitted herein.The present application further proposes a battery including the above-described battery cap. Due to the use of all the technical configurations of all the above embodiments, the battery has at least all the advantageous effects achieved by the technical configurations of the above embodiments, and repeated description will be omitted here.Here, a cylindrical type battery 21700 is used as one of the embodiments of the present application to illustrate that the gasket 100 is incorporated into the cylindrical type battery 21700 (the following content will be briefly described with a battery), and the gasket 100 is disposed at the end position of the battery case 3 with the cap 2 located in the closed space of the gasket 100, and when the battery is assembled, the end of the battery case 3 is bent so that the part of the gasket 100 is interposed between the cap 2 and the case 3, and this part is the first sub-body 11. This part is the second sub-body 12, and the material of the first sub-body 11 comprises one of soluble polytetrafluoroethylene and polyphenylene sulfide. Thus, if the internal temperature of the battery is too high, the first sub-body 11 of soluble PTFE and polyphenylene sulfide will not melt or will only partially melt to avoid short circuit of the battery due to direct contact between the housing 3 and the cap 2. The environment in which the second sub-body 12 is located does not have the requirement for the high temperature resistance of the first sub-bodies 11, so that the material of the second sub-body 12 may be the same as that of the first sub-body 11, or it may be different from the first sub-body 11, i.e., the material of the second sub-body 12 is composed of at least one of soluble polytetrafluoroethylene, polyphenylene sulfide, and polybutylene terephthalate.

Claims

A gasket configured to insulatively seal a gap between a cap (2) and a case (3) of a battery, and comprising a body (1) comprising a first sub-body (11) located between the case (3) and the cap (2); wherein the melting point of at least a part of the first sub-body (11) is higher than the temperature in the closed space of the case (3) in case the battery is in the maximum discharge state.The gasket according to claim 1, wherein the surface temperature of the case (3) is defined as A in case the case (3) is in the maximum discharge state; wherein A satisfies: 120°C≤A≤140°C ; wherein the material of the first sub-body (11) comprises at least one of soluble polytetrafluoroethylene and polyphenylene sulfide.The gasket according to claim 2, wherein the temperature of the housing (3) is defined as B in case the housing (3) is in the maximum unloading state; wherein B satisfies: 220°C≤B≤280°C.The seal according to claim 2 or 3, wherein the first sub-body (11) has a first state and a second state, wherein in the first state the surface temperature of the housing (3) is lower than the A-range of values, and in the second state the surface temperature of the housings (3) is in the A-range of values; wherein the thickness of the first sub-body between the housing (3) and the cap (2) when the first sub-body (11) is in the first state is defined as D1 and the thickness of the first sub-body between the housing (3) and the cap (2) when the first sub-body (11) is in the second state is defined as D2; wherein D1 and D2 satisfy: D2≥0.8D1.The seal according to any one of claims 2 to 4, wherein the body (1) further comprises a second sub-body (12) connected to the first sub-body (11), and the material of the second sub-body (12) is identical or not identical to the material of the first sub-body (11).The gasket of claim 5, wherein the material of the second sub-body (12) comprises at least one of soluble polytetrafluoroethylene, polyphenylene sulfide and polybutylene terephthalate.The seal of claim 5, wherein the material of the second sub-body (12) is polybutylene terephthalate; wherein the roughness of the first sub-body (11) is greater than that of the second sub-body (12).The gasket according to any one of claims 1 to 7, wherein the cap (2) further comprises a first side (2A) facing the housing (3) in the axial direction of the housing (3), and the melting point of at least the part of the first sub-body (11) located between the first side (2A) and the housing (3) is higher than the temperature in the closed space of the housing (3) when the battery is in the maximum discharge state.Seal according to one of Claims 1 to 8, wherein the body (1) is of hollow and annular configuration.A battery cap comprising: the gasket (100) of any one of claims 1 to 9; and a cap (2); wherein the first sub-body (11) of the gasket (100) is located between the cap (2) and the housing (3) of the battery.A battery comprising: a case (3); and the battery cap according to claim 10, which is disposed at one end of the case (3) and is located in the closed space of the case (3).

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