Secondary battery, battery pack and electric equipment

Abstract

The utility model relates to the technical field of batteries, in particular to a secondary battery, a battery pack and electric equipment. The secondary battery provided by the utility model comprises a shell and an electrode assembly accommodated in the shell, the electrode assembly comprises a positive pole piece, an isolating membrane and a negative pole piece, and the positive pole piece, the isolating membrane and the negative pole piece are sequentially stacked and wound; a hollow structure is formed in a center shaft of the electrode assembly, the hollow structure penetrates through the two axial ends of the electrode assembly, a fire extinguishing device is arranged in the hollow structure and comprises a shell, a cavity is formed in the shell, and a fire extinguishing agent is arranged in the cavity. When the battery has potential safety hazards, the shell of the fire extinguishing device can be broken, so that the fire extinguishing agent absorbs a large amount of heat or the temperature of a fire source is rapidly reduced, the interior of the battery is cooled or extinguished, the safety performance of the battery is improved, and the secondary battery is simple in structure and high in safety.

Description

Technical Field

[0001] The present disclosure relates to the field of battery technology, and in particular to a secondary battery, a battery pack and an electrical device. Background Art

[0002] As batteries are increasingly used in electric vehicles and grid energy storage, battery safety performance is receiving more and more attention. Battery safety issues are usually caused by thermal runaway.

[0003] When a battery experiences thermal runaway, the heat released by the active materials in the battery can reach several hundred joules per gram. The instantaneous heat generation can cause a violent redox reaction between the active materials and the electrolyte, producing a large amount of flammable gas. These gases cause the internal pressure of the battery to rise sharply, which may cause a fire, threatening the safety of the equipment and the personal safety of related personnel. Summary of the invention

[0004] The present disclosure provides a secondary battery, a battery pack and an electrical device to at least solve the above technical problems existing in the prior art.

[0005] A first aspect of the present disclosure provides a secondary battery, comprising: a housing and an electrode assembly accommodated in the housing;

[0006] The electrode assembly comprises a positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked and wound;

[0007] The central axis of the electrode assembly forms a hollow structure, and the hollow structure runs through both ends of the electrode assembly in an axial direction. A fire extinguishing device is arranged in the hollow structure, and the fire extinguishing device includes an outer shell, and the outer shell forms a cavity, and a fire extinguishing agent is arranged in the cavity.

[0008] Furthermore, the shell is made of a thermally decomposable material or a material that is soluble in acid or resistant to electrolyte corrosion and can be broken under pressure.

[0009] Furthermore, the fire extinguishing agent is perfluoroacetone.

[0010] Furthermore, the hollow structure is cylindrical, the outer shell is cylindrical, and the outer wall of the outer shell abuts against the inner wall of the hollow structure.

[0011] Furthermore, the outer wall of the shell is provided with notches.

[0012] Furthermore, there are multiple fire extinguishing devices, and the multiple fire extinguishing devices are arranged in sequence along the axial direction of the electrode assembly.

[0013] Furthermore, the secondary battery also includes a first limiter arranged in the hollow structure, the first limiter is located on the top of the fire extinguishing device, one end of the first limiter abuts against the fire extinguishing device, and the other end of the first limiter abuts against the shell.

[0014] Furthermore, the secondary battery also includes a second limiter arranged in the hollow structure, the second limiter is located at the bottom of the fire extinguishing device, one end of the second limiter abuts against the fire extinguishing device, and the other end of the second limiter abuts against the shell.

[0015] Furthermore, the thickness T of the shell satisfies: 0.1 mm≤T≤0.2 mm.

[0016] A second aspect of the present disclosure provides a battery pack, comprising the secondary battery described in the first aspect.

[0017] A third aspect of the present disclosure provides an electrical device, comprising the battery pack described in the second aspect.

[0018] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0019] The secondary battery provided by the embodiment of the present disclosure includes a shell and an electrode assembly contained in the shell; the electrode assembly includes a positive electrode sheet, a separator and a negative electrode sheet, which are sequentially stacked and wound; the central axis of the electrode assembly forms a hollow structure, the hollow structure runs through both ends of the electrode assembly in the axial direction, a fire extinguishing device is arranged in the hollow structure, the fire extinguishing device includes a shell, the shell forms a cavity, and a fire extinguishing agent is arranged in the cavity. When the battery has a safety hazard, the shell of the fire extinguishing device will rupture so that the fire extinguishing agent absorbs a large amount of heat or rapidly reduces the temperature of the fire source, so that the internal temperature of the battery is reduced or the fire is extinguished, thereby improving the safety performance of the battery. The secondary battery has a simple structure and high safety.

[0020] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other purposes, features and advantages of the exemplary embodiments of the present disclosure will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, in which:

[0022] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0023] Figure 1A schematic structural diagram of a secondary battery provided by an embodiment of the present disclosure is shown.

[0024] Explanation of the reference numerals in the figure: 1. Shell; 11. Hollow structure; 2. Fire extinguishing device; 3. Electrode assembly. DETAILED DESCRIPTION

[0025] In order to make the purpose, features, and advantages of the present disclosure more obvious and easy to understand, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0026] like Figure 1 As shown, the secondary battery provided by the embodiment of the present disclosure includes an electrode assembly 3 contained in the shell 1 and a shell 1; the electrode assembly 3 includes a positive electrode sheet, a separator and a negative electrode sheet, and the positive electrode sheet, the separator and the negative electrode sheet are stacked and wound in sequence; the positive electrode sheet is provided with a plurality of positive electrode ears, and the positive electrode ears are connected to the positive electrode, and the negative electrode sheet is provided with a plurality of negative electrode ears, and the negative electrode sheet is connected to the negative electrode. The central axis of the electrode assembly 3 forms a hollow structure 11, and the hollow structure 11 passes through both ends of the axial direction Z of the electrode assembly 3. A fire extinguishing device 2 is provided in the hollow structure 11, and the fire extinguishing device 2 includes a shell, and the shell forms a cavity, and a fire extinguishing agent is provided in the cavity. Optionally, when the electrode assembly 3 is wound, an installation space is reserved in the center to form the hollow structure 11, and then the fire extinguishing device 2 is inserted into the cavity of the hollow structure 11, which is simple to operate. When the battery has a safety hazard, the shell of the fire extinguishing device 2 will rupture, allowing the fire extinguishing agent to absorb a large amount of heat or rapidly reduce the temperature of the fire source, thereby cooling the inside of the battery or extinguishing the fire, thereby improving the safety performance of the battery. The secondary battery has a simple structure and high safety.

[0027] In other words, before the battery explodes, the fire extinguishing agent can be released from the outer shell in advance and enter the interior of the electrode assembly 3, thereby improving the safety performance of the battery.

[0028] The hollow structure 11 is the space left when the electrode assembly 3 is wound. The fire extinguishing device 2 utilizes the remaining space when the battery is sealed, thereby rationally utilizing the space inside the battery and improving the safety of the battery.

[0029] In the disclosed embodiment, the fire extinguishing device 2 is disposed at the center of the secondary battery, so that the heat inside the secondary battery can be consumed to avoid affecting the surrounding batteries during the fire extinguishing process.

[0030] In some specific embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer coated on the surface of the positive electrode current collector, and the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer coated on the surface of the negative electrode current collector. At the positive electrode of the electrode assembly 3, the tab is connected to the positive electrode sheet and extends from the electrode unit, and the tab can be directly cut from the positive electrode current collector; at the negative electrode of the electrode assembly 3, the tab is connected to the negative electrode sheet and extends from the electrode unit, and the tab can be directly cut from the negative electrode current collector.

[0031] In some specific embodiments, the housing is made of a thermally decomposable material or a material that is soluble in acid or resistant to corrosion by electrolyte and can be ruptured under pressure.

[0032] Thermally decomposable materials are materials with thermal decomposition properties. Thermally decomposable materials will decompose when a set temperature is reached. The set temperature can be 80°C, 100°C, 150°C or 200°C, etc. Acid-soluble materials can be materials that can decompose under acidic conditions. Pressure-resistant materials can rupture under a certain external pressure.

[0033] In some specific embodiments, when a battery poses a safety hazard, the temperature inside the battery will gradually increase. When the temperature rises to a certain level, the outer shell close to the electrode assembly 3 will rupture by itself, and the fire extinguishing agent will penetrate into the surface of the electrode assembly 3 through the rupture gap, thereby cooling the battery or extinguishing the fire, thereby controlling the battery to prevent fire and explosion.

[0034] In some specific embodiments, the outer shell is made of glass or other insulating materials. Under special battery conditions, the electrolyte may burn when it meets water, producing HF that dissolves in water to obtain hydrofluoric acid. One of the main components of glass is silicon dioxide, which reacts with hydrofluoric acid to produce silicon tetrafluoride and water. The glass outer shell will slightly melt with the hydrofluoric acid, thereby destroying the wall of the outer shell and releasing the fire extinguishing agent.

[0035] Optionally, the outer shell is cylindrical, and the pressure resistance of the cylindrical glass structure meets the internal pressure conditions of the battery. When designing, it is assumed that the pressure of the battery explosion-proof valve is 1.9MPa, and the glass column can be made to be 1.6MPa, or the explosion-proof valve opening pressure is greater than the bursting pressure of the outer shell of the fire extinguishing device 2 ≥ 1.2MPa. The fire extinguishing agent in the glass shell can be released into the battery in advance to cool down the inside of the battery or extinguish the fire, thereby improving the safety performance of the battery.

[0036] In some specific embodiments, the fire extinguishing agent is perfluoroacetone. Perfluoroacetone has the characteristics of high density, high heat capacity, high specific heat, etc. It can absorb a large amount of heat in a short time, so that the temperature of the fire source is rapidly reduced, thereby achieving the effect of extinguishing the fire. In addition, perfluoroacetone can also form an inert gas layer to prevent air from contacting the fire source, further suppressing the development of the fire. Perfluoroacetone has excellent insulation ability and will not cause short circuits. Perfluoroacetone has characteristics that are highly compatible with battery fire extinguishing, which can improve the fire extinguishing effect.

[0037] In some specific embodiments, the hollow structure 11 is cylindrical and the outer shell is cylindrical, which reasonably utilizes the space left when the electrode assembly 3 is wound. The outer wall of the outer shell abuts against the inner wall of the hollow structure 11, which improves the stability of the installation of the fire extinguishing device 2.

[0038] In some specific embodiments, the outer wall of the shell is provided with notches. When a potential safety hazard occurs in the battery, the shell of the fire extinguishing device 2 will be broken preferentially at the notches, so that the fire extinguishing agent absorbs a large amount of heat or rapidly reduces the temperature of the fire source, thereby cooling the inside of the battery or extinguishing the fire, thereby improving the safety performance of the battery. Optionally, the notches may be a concave structure, such as a groove.

[0039] In some specific embodiments, there are multiple fire extinguishing devices 2, and the multiple fire extinguishing devices 2 are sequentially arranged along the axial direction Z of the electrode assembly 3. When a potential safety hazard occurs in the battery, the safety of the battery can be improved as long as the shell of one of the fire extinguishing devices 2 is broken so that the fire extinguishing agent absorbs a large amount of heat or the temperature of the fire source is rapidly reduced.

[0040] In some specific embodiments, the secondary battery also includes a first limit member arranged in the hollow structure 11, the first limit member is located at the top of the fire extinguishing device 2, one end of the first limit member abuts against the fire extinguishing device 2, and the other end of the first limit member abuts against the outer shell, which can improve the installation stability of the fire extinguishing device 2 and reduce the possibility of shaking of the fire extinguishing device 2.

[0041] In some specific embodiments, the secondary battery also includes a second limit member arranged in the hollow structure 11, the second limit member is located at the bottom of the fire extinguishing device 2, one end of the second limit member abuts against the fire extinguishing device 2, and the other end of the second limit member abuts against the outer shell, which can improve the installation stability of the fire extinguishing device 2 and reduce the possibility of shaking of the fire extinguishing device 2.

[0042] The first limiting member and the second limiting member can both be plate-shaped or block-shaped, which can improve the installation stability of the fire extinguishing device 2 and reduce the possibility of shaking of the fire extinguishing device 2.

[0043] The first limiting member and the second limiting member are made of insulating material to avoid the occurrence of short circuit.

[0044] In some specific embodiments, the thickness T of the shell satisfies: 0.1mm≤T≤0.2mm. Before the explosion-proof valve explodes, the fire extinguishing agent in the shell can be released into the battery in advance to cool down the battery or extinguish the fire, thereby improving the safety performance of the battery.

[0045] The battery pack provided in the embodiment of the present disclosure includes the secondary battery provided in the embodiment of the present disclosure. The electric device provided in the embodiment of the present disclosure, which may be a vehicle or electronic device, includes the battery pack provided in the embodiment of the present disclosure. Since the electric device or battery pack provided in the embodiment of the present disclosure has the same advantages as the secondary battery provided in the embodiment of the present disclosure, they will not be described in detail here.

[0046] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved, and this document does not limit this.

[0047] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0048] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A secondary battery, characterized in that: include: A shell (1) and an electrode assembly (3) accommodated in the shell (1); The electrode assembly (3) comprises a positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked and wound; The central axis of the electrode assembly (3) forms a hollow structure (11), the hollow structure (11) passes through both ends of the electrode assembly (3) in an axial direction, a fire extinguishing device (2) is arranged in the hollow structure (11), and the fire extinguishing device (2) comprises an outer shell, the outer shell forms a cavity, and a fire extinguishing agent is arranged in the cavity.

2. The secondary battery according to claim 1, characterized in that: The shell is made of a thermally decomposable material or a material that is soluble in acid or resistant to electrolyte corrosion and can be broken under pressure.

3. The secondary battery according to claim 1, characterized in that: The fire extinguishing agent is perfluoroacetone.

4. The secondary battery according to claim 1, characterized in that: The hollow structure (11) is cylindrical, the outer shell is cylindrical, and the outer wall of the outer shell abuts against the inner wall of the hollow structure (11).

5. The secondary battery according to claim 1, characterized in that: The outer wall of the shell is provided with notches.

6. The secondary battery according to claim 1, characterized in that: The number of the fire extinguishing devices (2) is multiple, and the multiple fire extinguishing devices (2) are arranged in sequence along the axial direction of the electrode assembly (3).

7. The secondary battery according to claim 1, characterized in that: It also includes a first stopper arranged on the hollow structure (11), the first stopper being located at the top of the fire extinguishing device (2), one end of the first stopper abutting against the fire extinguishing device (2), and the other end of the first stopper abutting against the outer shell; And / or, it also includes a second limit member arranged on the hollow structure (11), the second limit member is located at the bottom of the fire extinguishing device (2), one end of the second limit member abuts against the fire extinguishing device (2), and the other end of the second limit member abuts against the outer shell.

8. The secondary battery according to claim 1, characterized in that: The thickness T of the shell satisfies: 0.1 mm≤T≤0.2 mm.

9. A battery pack, characterized in that: A secondary battery comprising the secondary battery according to any one of claims 1 to 8.

10. An electrical device, characterized in that: A battery pack comprising the battery pack of claim 9.

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