Safe top cover assembly and battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a safety type top cover assembly which comprises a top cover and a flame-retardant supporting piece which are overlapped, a plurality of pre-filling holes are formed in one surface, far away from the top cover, of the flame-retardant supporting piece, each pre-filling hole is filled with flame-retardant particles, and a first coating layer covers the plurality of pre-filling holes. The utility model has high space utilization rate, and can quickly block chain reaction to avoid thermal runaway caused by continuous rising of heat in the battery. In addition, the utility model also provides a battery.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and particularly relates to a safety top cover assembly and a battery. Background Art

[0002] The safety of batteries is not only related to the electrolyte, but also usually to the structure of the top cover. Since the electrolytes of current secondary batteries are mostly organic liquid electrolytes, their solvents have very low flash points and are extremely flammable. This makes it very easy for the battery to cause thermal runaway and lead to safety problems under abuse. If flame retardant additives are directly added to the electrolyte, it is easy to increase the viscosity of the electrolyte and reduce the conductivity of the electrolyte, thereby reducing the electrical performance and cycle performance of the battery cell. Therefore, in order to ensure the high quality of the battery and effectively improve the safety of the battery structure, a new top cover structure and battery are needed to solve the above problems. Utility Model Content

[0003] One of the purposes of the present invention is to address the deficiencies of the prior art and provide a safety top cover assembly that can quickly block chain reactions and prevent the heat in the battery from continuing to rise and causing thermal runaway.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A safety top cover assembly comprises a stacked top cover and a flame retardant support member, wherein a side of the flame retardant support member away from the top cover has a plurality of pre-filled pores, each of the pre-filled pores is filled with flame retardant particles, and a first coating layer covers the plurality of pre-filled pores.

[0006] As an improvement of the top cover assembly of the present invention, the porosity of a side of the flame retardant support member away from the top cover is at least 10% to 50%.

[0007] As an improvement of the top cover assembly of the present invention, the explosion-proof valve of the top cover corresponds to the reinforcement portion of the flame retardant support member, and the reinforcement portion is provided with a plurality of exhaust holes, and the plurality of exhaust holes are arranged evenly or unevenly. The reinforcement portion can improve the structural strength of the flame retardant support member corresponding to the explosion-proof valve position.

[0008] As an improvement of the top cover assembly of the present invention, the first covering layer is provided with through holes corresponding to the exhaust holes to ensure efficient exhaust of the exhaust holes.

[0009] As an improvement of the top cover assembly of the present invention, the reinforcement portion bulges in a direction away from the top cover to form an accommodating cavity, and the plurality of exhaust holes are arranged on one side of the accommodating cavity to effectively increase the volume and exhaust efficiency of the exhaust area.

[0010] As an improvement of the top cover assembly of the present invention, the inner wall of the reinforcement portion has a plurality of partitions, and the plurality of partitions divide the internal accommodating cavity of the reinforcement portion into a plurality of exhaust cavities, so as to more effectively improve the structural strength of the reinforcement portion.

[0011] As an improvement of the top cover assembly of the present invention, the melting point of the first coating layer is 85°C to 140°C, the melting point of the first coating layer is lower than the melting point of the flame-retardant support member, the first coating layer can be a coating film, and the first coating layer can separate the electrolyte of the battery and the flame-retardant particles filled in the flame-retardant support member during normal operation of the battery.

[0012] As an improvement of the top cover assembly of the present invention, the pre-filled pores are circular hole structures, and the pore diameter of the circular hole structure is 400 μm to 1000 μm.

[0013] As an improvement to the top cover assembly of the present invention, the plurality of pre-filled pores are arranged in a dot matrix or a grid.

[0014] As an improvement of the top cover assembly of the present invention, the explosion-proof valve and the reinforcement portion are both arranged in the center of the top cover assembly.

[0015] The second object of the present utility model is to provide a battery, comprising the top cover assembly as described above, wherein the battery may be a lithium ion battery, a sodium ion battery, a magnesium ion battery, etc.

[0016] The beneficial effects of the present invention are as follows: the present invention includes a stacked top cover and a flame-retardant support member, a side of the flame-retardant support member away from the top cover has a plurality of pre-filled pores, each pre-filled pore is filled with flame-retardant particles, a first coating layer covers the plurality of pre-filled pores, the first coating layer can play a role in coating and protecting the flame-retardant particles at a first preset temperature, and if the first coating layer melts at a second preset temperature, the flame-retardant particles are used to fall into the electrolyte in the battery when the second preset temperature is reached, so as to have an effective flame-retardant effect on the battery, which can effectively avoid thermal runaway of the battery and effectively improve the safety performance of the top cover assembly and the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an exploded schematic diagram of the top cover assembly of the present invention.

[0018] Figure 2 It is a three-dimensional structural diagram of the top cover assembly of the utility model.

[0019] Figure 3 It is a bottom view of the top cover assembly of the utility model.

[0020] Figure 4This is a bottom view of the top cover assembly of the present invention without being covered with the first covering layer.

[0021] Figure 5 This is a three-dimensional structural diagram of the flame-retardant support member of the present invention.

[0022] Among them: 1. Top cover; 11. Explosion-proof valve; 2. Flame-retardant support member; 21. Reinforcement part; 22. Exhaust hole; 3. First covering layer. DETAILED DESCRIPTION

[0023] If certain words are used in the specification and claims to refer to specific components, those skilled in the art should understand that manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of the components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". In the utility model, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two components. For those of ordinary skill in the art, the specific meanings of the above terms in the utility model can be understood according to the specific circumstances.

[0024] The following is combined with Figures 1 to 5 The present invention is further described in detail with reference to the following specific embodiments, but is not intended to limit the present invention.

[0025] Example 1

[0026] A safety top cover assembly, such as Figures 1-2 As shown, it includes a top cover 1 and a flame retardant support 2 stacked together. The side of the flame retardant support 2 away from the top cover 1 has a plurality of pre-filled pores, each of which is filled with flame retardant particles. The first coating layer 3 covers the plurality of pre-filled pores.

[0027] Among them, the flame retardant particles can be one or more of triphenyl phosphate (TPP), trifluoroethyl phosphite (TTFP), ammonium polyphosphate (APP), and magnesium hydroxide particles, or appropriate flame retardants can be selected as needed. The flame retardant support 2 can also contain flame retardant components itself. When the battery is running to the point of thermal runaway, the first coating layer 3 wrapping the flame retardant particles is heated and melted, and the electrolyte vapor dissolves the flame retardant particles to exert a flame retardant effect and block the potential thermal runaway hazards.

[0028] Specifically, the flame-retardant support member 2 can be made of a porous insulating material with a porous structure, such as ceramic or plastic with a melting point above 140°C. Installed beneath the top cover 1, the flame-retardant support member 2 serves as both a carrier for the flame-retardant additive and an insulating medium that prevents direct contact between the battery cell and the top cover 1, preventing a short circuit between the positive and negative electrodes. The first coating layer 3 can be attached to the surface of the flame-retardant support member 2, acting as a surface modification layer.

[0029] Among them, before the flame retardant support 2 and the top cover 1 are assembled, a plurality of pre-filled pores are formed on the side of the flame retardant support 2 away from the top cover 1. The flame retardant additive can be dissolved in a volatile solvent and then immersed in the pre-filled pores of the flame retardant support 2. The solvent is then evaporated to allow the flame retardant additive to remain in the pre-filled pores of the flame retardant support 2. Next, a layer of PE film is coated on the side of the flame retardant support 2 with the pre-filled pores to block subsequent electrolyte from entering the pores of the flame retardant support 2, thereby effectively preventing the flame retardant additive from dissolving during normal operation of the battery.

[0030] Preferably, see Figures 3 to 5 The explosion-proof valve 11 of the top cover 1 corresponds to the reinforced portion 21 of the protective support member 2. A plurality of exhaust holes 22 are defined on a side of the reinforced portion 21 facing away from the top cover 1. The first cladding layer 3 is provided with through holes corresponding to the exhaust holes 22. The plurality of exhaust holes 22 serve as gas passages after the explosion-proof valve 11 of the top cover 1 is opened. The apertures of the exhaust holes 22 may be equal or unequal, and the spacing between the exhaust holes 22 may be equal or unequal. The plurality of exhaust holes 22 are not blocked by the first cladding layer 3.

[0031] In some embodiments, the porosity of the side of the flame retardant support 2 away from the top cover 1 can be 15±5%, 30±5% or 45±5% to reasonably control the amount of flame retardant added, and the pre-filled pores can be a circular pore structure, and the pore size of the circular pore structure can be 400μm~600μm, 600μm~800μm, 800μm~1000μm.

[0032] Preferably, the plurality of pre-filled pores may be arranged in a lattice or a grid.

[0033] Furthermore, in some embodiments, the reinforcement portion 21 may bulge in a direction away from the top cover 1 to form an accommodating cavity, and the plurality of exhaust holes 22 are arranged on one side of the accommodating cavity.

[0034] Preferably, the inner wall of the reinforcement part 21 has multiple partitions, which divide the internal accommodating cavity of the reinforcement part 21 into multiple exhaust cavities. Through the synergistic effect of the explosion-proof valve 11, flame retardant particles and the reinforcement part 21, the battery can have both flame retardant properties and efficient pressure relief.

[0035] Preferably, the melting point of the first coating layer 3 is 85°C to 140°C, and the melting point of the first coating layer 3 is lower than the melting point of the flame retardant support 2, so that the first coating layer 3 melts and efficiently releases the flame retardant when thermal runaway occurs in the battery cell.

[0036] Example 2

[0037] A battery includes the top cover assembly of embodiment 1, and the battery can be a square shell battery.

[0038] Obviously, the present invention fills and coats the porous insulating material with flame retardants. Under normal use of the battery cell, the flame retardant will not leak into the electrolyte, thus avoiding adverse effects on the battery cell's electrical performance and cycle performance. Once the battery cell temperature exceeds 80-140°C, the coating layer covering the surface of the porous insulating material breaks and releases the flame retardant additive, which can quickly block the chain reaction and prevent the continued rise in heat from causing thermal runaway. In addition, the flame retardant additive is filled in the top cover assembly, making full use of the limited space inside the battery cell, allowing the flame retardant additive to be released in a timely manner, so as not to reduce the battery cell's electrical performance while improving the battery cell's safety performance under extreme abuse conditions, thus avoiding safety accidents and loss of life and property caused by abuse.

[0039] Based on the disclosure and teachings of the above description, those skilled in the art will be able to make changes and modifications to the above embodiments. Therefore, the utility model is not limited to the specific embodiments described above. Any obvious improvements, substitutions, or modifications made by those skilled in the art based on the present utility model fall within the scope of protection of the present utility model. In addition, although certain specific terms are used in this description, these terms are for convenience only and do not constitute any limitation on the present utility model.

Claims

1. A safety top cover assembly, characterized in that: include: A top cover (1) and a flame retardant support member (2) stacked together; The side of the flame retardant support (2) away from the top cover (1) has a plurality of pre-filled pores; Each of the pre-filled pores is filled with flame retardant particles, and a first coating layer (3) covers the plurality of pre-filled pores.

2. The safety top cover assembly according to claim 1, wherein: The porosity of the side of the flame-retardant support member (2) away from the top cover (1) is at least 10% to 50%.

3. The safety top cover assembly according to claim 1 or 2, characterized in that: The explosion-proof valve (11) of the top cover (1) corresponds to the reinforcement portion (21) of the flame-retardant support member (2), and the reinforcement portion (21) is provided with a plurality of exhaust holes (22).

4. The safety top cover assembly according to claim 3, wherein: The first coating layer (3) is provided with a through hole corresponding to the exhaust hole (22).

5. The safety top cover assembly according to claim 3, wherein: The reinforcement portion (21) bulges in a direction away from the top cover (1) to form an accommodating cavity, and a plurality of exhaust holes (22) are arranged on one side of the accommodating cavity.

6. The safety top cover assembly according to claim 5, wherein: The inner wall of the reinforcement part (21) has a plurality of partitions, and the plurality of partitions divide the internal accommodation cavity of the reinforcement part (21) into a plurality of exhaust cavities.

7. The safety top cover assembly according to claim 1 or 2, characterized in that: The melting point of the first coating layer (3) is 85°C to 140°C, and the melting point of the first coating layer (3) is lower than the melting point of the flame-retardant support member (2).

8. The safety top cover assembly according to claim 1 or 2, characterized in that: The pre-filled pores are circular pore structures, and the pore diameter of the circular pore structure is 400 μm to 1000 μm.

9. The safety top cover assembly according to claim 1 or 2, characterized in that: The plurality of pre-filled pores are arranged in a dot matrix or a grid.

10. A battery, characterized in that: The utility model comprises a top cover assembly according to any one of claims 1 to 9.

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