Lithium battery open circuit protection valve and lithium battery

Abstract

The utility model discloses a lithium battery open circuit protection valve and a lithium battery. The protection valve is installed on the battery cover plate and comprises a sealing shell, the lower end face of the sealing shell can be broken when the temperature reaches the preset temperature, and the sealing shell is filled with chemical substances playing a role in circuit breaking protection of the interior of the lithium battery. The scheme provided by the utility model has no requirement on battery multiplying power and can be suitable for a high-multiplying-power battery. The protection valve can enable the interior of the battery to reach an open-circuit state when the temperature in the battery rises to a certain degree, charging and discharging are not continued, and continuous heating in the battery is avoided; in addition, even if the process fails, the pressure relief effect can be achieved when the internal pressure of the battery is too large, and therefore the purpose of protecting the battery is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery structures, and particularly relates to a lithium battery open-circuit protection valve and a lithium battery. Background Art

[0002] In the prior art, in order to prevent the battery from overheating and causing combustion and explosion, an FUSE is usually added to the battery cover, so that when the battery current is too large or the temperature is too high, it can play a role in protecting the battery. However, in the current development trend of high-rate batteries, the solution of adding an FUSE is no longer applicable to high-rate batteries due to the limitation of over-current capacity. Therefore, it is necessary to improve the related technology. Summary of the Utility Model

[0003] Aiming at the technical problem that the traditional technical solution of adding an FUSE to the battery cover to prevent the battery from overheating cannot be applied to high-rate batteries pointed out in the background art, the purpose of the utility model is to provide a lithium battery open-circuit protection valve and a lithium battery.

[0004] To achieve the purpose of the utility model, the technical solutions provided by the utility model are as follows:

[0005] First Aspect

[0006] The present application provides a lithium battery open-circuit protection valve, which is installed on the battery cover plate and includes a sealed housing that will rupture when the lower end face reaches a preset temperature. A chemical substance that plays an open-circuit protection role for the inside of the lithium battery is filled in the sealed housing.

[0007] Wherein, the protection valve is welded at the middle position of the battery cover plate.

[0008] Wherein, the sealed housing includes a protection valve upper cover, a protection valve valve wall, and a protection valve composite wall that are sequentially connected from top to bottom. The protection valve valve wall is annular, its upper end is connected to the protection valve upper cover, and its lower end is connected to the protection valve composite wall. The chemical substance is filled in the sealed cavity surrounded by the protection valve upper cover, the protection valve valve wall, and the protection valve composite wall.

[0009] Wherein, the protection valve composite wall is composed of two metal sheets with different thermal expansion coefficients through a laser welding method to form a composite material.

[0010] Wherein, the thickness of the composite material is 0.3 mm, and the thickness at the middle position is 0.05 ± 0.002 mm.

[0011] Wherein, the upper metal sheet is made of a material with a large expansion coefficient, and the lower metal sheet is made of a material with a low expansion coefficient.

[0012] Among them, the upper metal sheet is one of the following materials: iron-nickel-chromium, iron-manganese-nickel, manganese-copper-nickel, pure iron, brass; the upper metal sheet is one of the following materials: Ni36Fe, Ni39Fe, Ni40Fe, Ni42Fe, Ni50Fe.

[0013] Among them, the chemical substance is powdered phenolic resin.

[0014] Among them, the upper cover of the protection valve is an aluminum sheet with a notch.

[0015] Second aspect

[0016] This application provides a lithium battery, including the lithium battery open circuit protection valve described above.

[0017] Compared with the prior art, the beneficial effects of the present utility model are:

[0018] The solution provided by this application has no requirements for the battery rate and can be applied to high-rate batteries. When the internal temperature of the battery rises to a certain level, the protection valve can make the battery internal reach an open circuit state and no longer continue to charge and discharge, avoiding continuous heating inside the battery;

[0019] In addition, even if the above process fails, it can also achieve a pressure relief function when the internal pressure of the battery is too high, so as to achieve the purpose of protecting the battery. Description of the drawings

[0020] Figure 1 It is a schematic structural diagram of the protection valve provided by the embodiment of this application;

[0021] In the figure, the upper cover of the protection valve 2.1, the valve wall of the protection valve 2.2, the composite wall of the protection valve;

[0022] Figure 2 It is a schematic installation structure diagram of the protection valve provided by the embodiment of this application;

[0023] In the figure, the battery cover plate 1, the protection valve 2.

[0024] Figure 3 It is a schematic upper side structure diagram of the protection valve passed by the embodiment of this application;

[0025] Figure 4 It is a schematic lower side structure diagram of the protection valve provided by the embodiment of this application. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0027] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model 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 should not be construed as a limitation to the present utility model.

[0028] In the description of this patent, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "connection", "setting" should be understood in a broad sense. For example, it can be fixedly connected and set, or detachably connected and set, or integrally connected and set. It can refer to direct connection or indirect connection. For those of ordinary skill in the art, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0029] As Figures 1-4 shown, it is the structural diagram of the embodiment of this application.

[0030] Embodiment 1

[0031] This embodiment provides a lithium battery open circuit protection valve. The protection valve 2 is installed on the battery cover plate 1 and includes a sealing shell that will rupture when the lower end face reaches a preset temperature. A chemical substance that plays an open circuit protection role for the inside of the lithium battery is filled in the sealing shell. Preferably, the protection valve 2 is welded at the middle position of the battery cover plate 1.

[0032] It should be noted that the preset temperature can be 85°±5°.

[0033] Preferably, the sealing shell includes a protection valve upper cover 2.1, a protection valve valve wall 2.2, and a protection valve composite wall 2.3 that are connected in sequence from top to bottom. The protection valve valve wall 2.2 is annular, its upper end is connected to the protection valve upper cover 2.1, and its lower end is connected to the protection valve composite wall 2.3. The chemical substance is filled in the sealed cavity surrounded by the protection valve upper cover 2.1, the protection valve valve wall 2.2, and the protection valve composite wall 2.3.

[0034] It should be noted that the upper cover of the protection valve is welded to the battery cover plate. The area of the upper cover of the protection valve is larger than the area enclosed by the valve wall of the protection valve. Therefore, after the two are connected, the upper cover of the protection valve leaks out from the outside of the valve wall of the protection valve, and the edge of the upper cover of the protection valve can be welded to the battery cover plate.

[0035] It should be noted that both the upper cover 2.1 of the protection valve and the composite wall 2.3 of the protection valve are welded to the valve wall 2.2 of the protection valve.

[0036] It should be noted that the upper cover 2.1 of the protection valve is an aluminum sheet with a notch, which plays a role in sealing and pressure relief; the valve wall 2.2 of the protection valve plays a supporting role.

[0037] Preferably, the composite wall 2.3 of the protection valve is composed of two metal sheets with different coefficients of thermal expansion through laser welding to form a composite material. The thickness of the composite material is 0.3 mm, and the middle position is relatively weak, with a thickness of 0.05 ± 0.002 mm. The upper metal sheet is made of a material with a large coefficient of expansion, and the lower metal sheet is made of a material with a low coefficient of expansion.

[0038] Preferably, the material of the composite wall of the protection valve can be freely selected according to requirements. The upper metal sheet is one of the following materials: iron nickel chromium, iron manganese nickel, manganese copper nickel, pure iron, brass; the upper metal sheet is one of the following materials: Ni36Fe, Ni39FeNi40Fe, Ni42Fe, Ni50Fe.

[0039] Preferably, the chemical substance is powdered phenolic resin, which has insulation properties.

[0040] When the battery is working normally, with the change of temperature, the composite wall of the protection valve has a certain degree of freedom of deformation; when the temperature reaches 85° ± 5°, the middle position of the composite wall of the protection valve bends downward until the middle weak position breaks. At this time, the powdered phenolic resin inside the protection valve falls into the battery core and dissolves in the electrolyte; due to the insulation characteristics of phenolic resin, the electrolyte in which the phenolic resin is dissolved is insulated, preventing the possibility of continuous temperature rise, fire or even explosion during the continuous charging and discharging of the battery.

[0041] In addition, if the composite wall of the protection valve or the phenolic resin inside the protection valve fails, the upper cover of the protection valve can also burst when the battery pressure is too high, acting as an explosion-proof valve, that is, a pressure relief function.

[0042] Embodiment 2

[0043] This embodiment provides a lithium battery, including the above-mentioned lithium battery open circuit protection valve.

[0044] The basic principles, main features and advantages of the present utility model have been shown and described above. Those skilled in the art should understand that the present utility model is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present utility model and are not used to limit the present utility model. Without departing from the spirit and scope of the present utility model, the present utility model will have various changes and improvements, and these changes and improvements all fall within the scope of the present utility model claimed. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents.

Claims

1. A lithium battery open circuit protection valve, characterized in that, The protection valve (2) is installed on the battery cover plate (1), and it includes a sealing housing that will rupture when the lower end face reaches a preset temperature. A chemical substance that plays a role in open-circuit protection for the inside of the lithium battery is filled in the sealing housing.

2. The lithium battery open circuit protection valve according to claim 1, characterized in that, The protection valve (2) is welded at the middle position of the battery cover plate (1).

3. The lithium battery open circuit protection valve according to claim 1 or 2, characterized in that, The sealing housing includes a protection valve upper cover (2.1), a protection valve valve wall (2.2), and a protection valve composite wall (2.3) that are connected in sequence from top to bottom. The protection valve valve wall (2.2) is annular, its upper end is connected to the protection valve upper cover (2.1), and its lower end is connected to the protection valve composite wall (2.3). The chemical substance is filled in the sealed cavity formed by the protection valve upper cover (2.1), the protection valve valve wall (2.2), and the protection valve composite wall (2.3).

4. The lithium battery open circuit protection valve according to claim 3, characterized in that, The protection valve composite wall (2.3) is composed of two metal sheets with different coefficients of thermal expansion through laser welding to form a composite material.

5. The lithium battery open circuit protection valve according to claim 4, characterized in that, The thickness of the composite material is 0.3 mm, and the thickness at the middle position is 0.05 ± 0.002 mm.

6. The lithium battery open circuit protection valve according to claim 4, characterized in that, The upper metal sheet is made of a material with a large coefficient of thermal expansion, and the lower metal sheet is made of a material with a low coefficient of thermal expansion.

7. The lithium battery open circuit protection valve according to claim 6, wherein The upper metal sheet is one of the following materials: iron-nickel-chromium, iron-manganese-nickel, manganese-copper-nickel, pure iron, brass; the lower metal sheet is one of the following materials: Ni36Fe, Ni39FeNi40Fe, Ni42Fe, Ni50Fe.

8. The lithium battery open circuit protection valve according to claim 1 or 2, characterized in that, The chemical substance is powdered phenolic resin.

9. The lithium battery open circuit protection valve according to claim 6, characterized in that, The protection valve upper cover (2.1) is an aluminum sheet with a notch.

10. A lithium battery, characterized in that, A lithium battery open-circuit protection valve as described in any one of claims 1-9 is included.

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