An explosion-proof battery, battery pack and electric device

Abstract

The application discloses an explosion-proof battery, which comprises a battery shell, a battery cell and a wrapping layer, the battery cell is contained in the battery shell, and the wrapping layer is wrapped on the surface of the battery cell; the wrapping layer comprises a sealed shell, the sealed shell is provided with a sandwich cavity, and the sandwich cavity is filled with viscous insulating liquid; the application further discloses a battery pack and a power utilization equipment; the explosion-proof battery can effectively prevent the short circuit of the battery and eliminate the risk of self-ignition of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of secondary batteries, in particular to an explosion-proof battery, a battery pack and an electric device. BACKGROUND

[0002] The needle puncture test is a very effective and harsh method in the test of power batteries, which is used to simulate the process that the electric vehicle causes internal short circuit of the power battery due to the intrusion of foreign matter into the internal part of the power battery caused by collision during driving, and then the place of internal short circuit produces heat accumulation and self-ignition. After the steel needle just penetrates the battery, the internal part of the battery has a severe swelling phenomenon. Then, the battery monomer explodes instantaneously, accompanied by a fire phenomenon, and the battery starts to burn fiercely. For the battery, if the vehicle-mounted battery pack is pierced by a steel needle, it is very likely to cause a thermal runaway condition.

[0003] To reduce such situations, relevant personnel have been researching how to improve the safety performance of the battery to meet the requirements of the needle puncture test. For example, a high-strength polymer lithium ion battery with puncture resistance is disclosed in CN216793780U, which adopts a high-strength polymer outer box, so that the overall battery structure has excellent puncture resistance. A puncture-resistant battery pack metal shell structure is disclosed in CN208674191U, which effectively protects the battery pack metal shell by using the high-strength characteristics of carbon fiber and the high-toughness characteristics of glass fiber to prevent the battery pack from being punctured. However, in these solutions, although the protection and safety measures of the battery have been improved, the safety performance of the battery itself cannot be improved due to excessive reliance on external protection measures. SUMMARY

[0004] The technical problem to be solved by the present application is to provide an explosion-proof battery which can effectively prevent short circuit of the battery and eliminate the risk of self-ignition of the battery.

[0005] To solve the above technical problems, the present application provides the following technical solutions:

[0006] The present application provides an explosion-proof battery in a first aspect, comprising:

[0007] a battery shell,

[0008] a battery cell accommodated in the battery shell; and

[0009] a wrapping layer covering the surface of the battery cell, the wrapping layer comprising a sealed shell having a sandwich cavity in the sealed shell, the sandwich cavity being filled with a viscous insulating liquid.

[0010] In an optional embodiment, the viscous insulating liquid comprises, by weight parts, 107 silicone rubber 100 parts, gum rosin tackifier 5-8 parts, TOTM 1-3 parts, diphenylsilanediol 1.5 parts.

[0011] In an optional embodiment, the viscous insulating liquid has a viscosity of 1500-2000 mPa·s at 25°C.

[0012] In an optional embodiment, the sealed shell is a sealed bag body.

[0013] In an optional embodiment, the sealed bag body is a polytetrafluoroethylene bag body.

[0014] In an optional embodiment, the wrapping layer at least covers the top surface, bottom surface and side surface of the battery cell.

[0015] In an optional embodiment, the battery cell is a plurality of battery cells, and the plurality of battery cells are arranged in a stack to form an integrated body; and the wrapping layer covers the surface of the integrated body.

[0016] In an optional embodiment, the battery cell is a plurality of battery cells, and the wrapping layer covers the surface of each battery cell.

[0017] The second aspect of the present application provides a battery pack comprising a plurality of the explosion-proof battery.

[0018] The third aspect of the present application provides a power-using device comprising the battery pack.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. The explosion-proof battery of the present application has a wrapping layer arranged on the outside of the battery cell, and the wrapping layer is filled with a viscous and insulating viscous insulating liquid. When an external object penetrates into the battery, the viscous insulating liquid can easily wrap the surface of the penetrating object due to its good viscosity, and its excellent insulation can block the path formed by the contact between the metal penetrating object and the inside of the battery cell, thereby avoiding short circuit and thermal runaway of the battery, and eliminating the risk of self-ignition of the battery.

[0021] 2. The explosion-proof battery of the present application can meet the requirements of the needle penetration test.

[0022] 3. The explosion-proof battery of the present application has a simple structure, low cost and is easy to mass-produce.

[0023] 4. The explosion-proof battery of the present application has good high-temperature resistance and low-temperature resistance, can be used in a wide working range, and can be applied to complex environments. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The wrapping mode of the battery cell in the first embodiment of the present application;

[0025] Figure 2 The wrapping mode of the battery cell in the second embodiment of the present application;

[0026] 1. battery cell; 2. wrapping layer. DETAILED DESCRIPTION

[0027] The present application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0029] In order to improve the safety performance of the battery to meet the requirements of the needle test, the existing scheme is to set a high-strength metal or polymer shell outside the battery, prevent foreign objects from penetrating by strengthening the shell, and achieve the purpose of explosion-proof. However, this way leads to high cost and heavy weight of the battery, and loading into a vehicle or other electrical equipment will increase the weight of the equipment, and the protection effect under heavy impact still needs to be verified in practice.

[0030] The present application provides a new solution, focusing on the internal part of the battery as the starting point, and blocking the short circuit by using viscous insulating liquid, which fundamentally eliminates the risk of self-ignition of the battery.

[0031] Specifically, please refer to Figures 1-2 The present application provides an explosion-proof battery, which comprises a battery shell (not shown in the figure), a battery cell 1 and a wrapping layer 2. The battery cell is contained in the battery shell, and the wrapping layer is wrapped on the surface of the battery cell. The wrapping layer comprises a sealed shell, the sealed shell has a sandwich cavity, and the sandwich cavity is filled with viscous insulating liquid.

[0032] Figure 1A schematic diagram of an explosion-proof battery according to an embodiment of the present application is shown. As can be seen from the diagram, the battery cell is covered by a wrapping layer filled with viscous insulating liquid inside, so that the metal piercing object will first pierce the wrapping layer before piercing the battery cell in the needle penetration test or in the actual collision process. Since the viscous insulating liquid inside the wrapping layer has good adhesion, it will adhere to and wrap around the surface of the metal piercing object to form a covering layer; meanwhile, the viscous insulating liquid also has good insulation, so it will block the path formed by the metal piercing object and the inside of the battery cell, avoiding short circuit in the battery cell, thus eliminating the occurrence of thermal runaway and combustion of the battery.

[0033] In the present application, the viscous insulating liquid needs to have a certain viscosity. The presence of viscosity makes the viscous insulating liquid exhibit good adhesion to different substrates, ensuring that the viscous insulating liquid can adhere to the surface of the piercing object and form a complete covering layer when the piercing object pierces. If the viscosity of the viscous insulating liquid is too small, the viscous insulating liquid cannot adhere well to the surface of the metal piercing object during the piercing process, thus it cannot form a good insulating covering layer, and the effect of blocking the path formed by the metal piercing object and the inside of the battery cell is not good. In some embodiments of the present application, the viscosity of the viscous insulating liquid at 25°C is at least 1000 mPa·s, for example, at least 1000 mPa·s, at least 1100 mPa·s, at least 1200 mPa·s, at least 1300 mPa·s, at least 1400 mPa·s, at least 1500 mPa·s, at least 1600 mPa·s, at least 1700 mPa·s, at least 1800 mPa·s, etc. However, the viscosity of the viscous insulating liquid cannot be too large, on the one hand, the viscous insulating liquid cannot be injected into the interlayer cavity of the sealed shell; on the other hand, the viscous insulating liquid is also difficult to distribute uniformly in the interlayer cavity. Therefore, in general, the viscosity of the viscous insulating liquid at 25°C needs to be controlled to be no more than 2000 mPa·s.

[0034] In the present application, the viscous insulating liquid also needs to have a certain insulation. Sufficient insulation can make the viscous insulating liquid adhered to the surface of the piercing object to form a covering layer effectively isolate the piercing object from the battery cell, thus avoiding short circuit in the battery cell. If the insulation of the viscous insulating liquid is too poor, the covering layer formed by the viscous insulating liquid may be electrically broken down, resulting in insulation failure. In some embodiments of the present application, the volume resistivity of the viscous insulating liquid is at least 1.0×10 14 Ω·cm, for example, at least 1.0×10 14 Ω·cm, at least 2.0×10 14 Ω·cm, at least 3.0×10 14 Ω·cm, at least 4.0×10 14at least 5.0 x 10-4 14 at least 6.0 x 10-4 14 at least 7.0 x 10-4 14 at least 8.0 x 10-4 14 at least 9.0 x 10-4 14 at least 1.0 x 10-4 15 at least 2.0 x 10-4 15 at least 3.0 x 10-4 15 at least 4.0 x 10-4 15 at least 5.0 x 10-4 15 at least 5.0 x 10-4

[0035] In the present application, the viscous insulating liquid preferably comprises the following components by weight: 107 silicone rubber 100 parts, gum rosin tackifier 5-8 parts, TOTM 1-3 parts, diphenyl silicone diol 1.5 parts. Among them, 107 rubber is in liquid state at room temperature, which has good adhesion and insulation, so it is suitable as the main component of the viscous insulating liquid. Gum rosin tackifier is also a liquid at room temperature, which can increase the adhesion of the composition as a tackifier, so that the composition can be well attached to the surface of various piercing objects. The role of TOTM is plasticizer, which can adjust the viscosity of the composition. Diphenyl silicone diol is a structure control agent, which can improve the processing performance of the rubber. Through the use of the above several components, not only does the composition have suitable viscosity and insulation, so that when the piercing object pierces the battery cell, it can form an isolation layer on the surface of the piercing object; moreover, the composition has excellent high temperature and low temperature resistance, which can meet the requirements of the battery in various scenes; in addition, the properties of the composition are very stable and do not react with the electrolyte.

[0036] The viscous insulating liquid composition provided above has a viscosity range of 1500-2000 mPa·s at 25℃, a volume resistivity of up to 10 15 Ω·cm, a breakdown strength of up to 20 kV / mm, an operating temperature of -60℃ to +200℃, and very excellent performance.

[0037] In some embodiments of the present application, the wrapping layer at least covers the top surface, the bottom surface and the side surface of the battery cell, so as to completely wrap the entire battery cell therein. Of course, the wrapping layer can also wrap other parts that need protection, wherein the other parts that need protection refer to components that may cause short circuit after contacting with the metal piercing object, such as the positive electrode, the adapter plate, the negative electrode adapter plate, etc.

[0038] In this invention, the sealing shell of the encapsulation layer can be either a rigid shell or a flexible shell. Compared with a rigid shell, a flexible shell can better adapt to the shape of the battery cell and has a better encapsulation effect on the battery cell.

[0039] In this invention, the sealing shell needs to have a good sealing effect to ensure that the built-in viscous insulating liquid will not leak when no penetrating object enters the battery cell. The material used to prepare the sealing shell needs to have good weather resistance and stability, and be able to withstand high and low temperatures during normal use, while not reacting with the electrolyte.

[0040] In a preferred embodiment of the present invention, the sealing shell is a flexible bag. The material of the flexible bag includes, but is not limited to, polytetrafluoroethylene (PTFE), preferably PTFE. PTFE has excellent heat and cold resistance, and can be used for extended periods at temperatures ranging from -180 to 260°C; furthermore, PTFE is resistant to acids, alkalis, and various organic solvents, exhibiting excellent stability and not reacting with various electrolytes. In addition, PTFE has good processability and can be easily fabricated into bags. Therefore, PTFE is very suitable as a material for preparing flexible bags.

[0041] In this invention, the amount of viscous insulating liquid inside the sealed housing must be appropriate to ensure that the viscous insulating liquid is distributed throughout the sealed housing covering all parts of the battery cell, thereby providing comprehensive protection for the battery cell. Furthermore, it is necessary to ensure that the viscous insulating liquid inside the sealed housing is sufficient to adhere to and coat the surface of any object that may pierce the casing. If the amount of viscous insulating liquid is insufficient, on the one hand, some areas within the interlayer cavity of the sealed housing will lack viscous insulating liquid distribution; on the other hand, when an object pierces the protective layer, the internal viscous insulating liquid will be insufficient to adhere to and coat the surface of the object, thus failing to achieve a good protective effect.

[0042] In this invention, the battery cell inside the battery casing can be one or more (two or more). When there are two or more cells, they can be encapsulated in two ways. In the first encapsulation method, multiple cells are first stacked and arranged to form a whole, and then a wrapping material containing a viscous insulating liquid (such as a polytetrafluoroethylene bag) is wrapped around the outer surface of the whole, as shown in the attached figure. Figure 1 As shown.

[0043] In the second coating method, during the process of stacking and arranging the individual cells to form a whole, a wrapping material containing an embedded viscous insulating liquid is first placed between the individual cells to separate them. Then, the wrapping material is used to coat the outer surface of the entire cell assembly, as detailed in the attached diagram. Figure 2The advantages of the coating method are that the battery cells are separated from each other, so that when a single battery cell is punctured, the other battery cells can be protected from being affected. Meanwhile, the wrapping material placed between the battery cells can act as a buffer during external impact on the battery, thereby protecting the battery cells.

[0044] It should be noted that the coating method of the battery cells in the present application includes but is not limited to the above two methods, for example, the wrapping material can be first coated on the surface of a single battery cell, and then stacked to form a whole.

[0045] Compared with the existing explosion-proof battery, the explosion-proof battery of the present application only needs to coat a wrapping layer with a built-in viscous insulating liquid on the surface of the battery cell, so that a good short-circuit prevention and explosion-proof effect can be achieved, and the effect is reliable. The explosion-proof device (i.e. the wrapping layer) of the explosion-proof battery has a simple structure and low cost, and is easy to mass-produce. In the process of producing the battery, the wrapping layer can be directly integrated into the preparation process of the battery, so that the production process can be integrated.

[0046] The present application further provides a battery pack comprising a plurality of the above-mentioned explosion-proof batteries. It can be understood that the battery pack also has the corresponding short-circuit prevention and explosion-proof effect. Preferably, a plurality of the above-mentioned explosion-proof batteries can be divided into a matrix form of multiple rows, multiple columns and multiple layers according to a certain rule, and then arranged in the battery pack, so that the internal space of the battery pack can be fully utilized, and the layout and direction of the busbars, wire harnesses and the like in the battery pack can be optimized, and the battery cells have stronger stability and safety and higher energy density in the battery pack.

[0047] The present application also provides an electric device comprising the above-mentioned battery pack. The electric device includes but is not limited to an electric vehicle, an electric motorcycle, a power storage device, an energy storage device and the like.

[0048] The present application will be further described in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it. However, the embodiments are not intended to limit the present application.

[0049] In the following examples, the experimental methods are conventional methods unless otherwise specified, and the materials, reagents and the like used are commercially available unless otherwise specified.

[0050] Example 1

[0051] The present embodiment provides an explosion-proof battery comprising a battery shell and a battery cell accommodated in the battery shell, and the entire surface of the battery cell is coated with a wrapping layer. The wrapping layer is obtained by filling viscous liquid rubber into a polytetrafluoroethylene bag and sealing the bag.

[0052] The components of the viscous liquid rubber are: 107 silicone rubber 500g, liquid cumarone tackifier 25g, TOTM 5g, diphenylsilanediol 7.5g. Stir and mix in a mixer until uniform.

[0053] Example 2

[0054] Example 2 differs from Example 1 in that the components of the viscous liquid rubber are: liquid 107 silicone rubber 500g, liquid cumarone tackifier 30g, TOTM 10g, diphenylsilanediol 7.5g. Stir and mix in a mixer until uniform.

[0055] Example 3

[0056] Example 3 differs from Example 1 in that the components of the viscous liquid rubber are: liquid 107 silicone rubber 500g, liquid cumarone tackifier 40g, TOTM 15g, diphenylsilanediol 7.5g. Stir and mix in a mixer until uniform.

[0057] Puncture test

[0058] The battery sample is clamped in a fixed clamp, and the movable clamp with a puncture needle is moved at a set speed (50mm / min, 100mm / min, 150mm / min, 200mm / min, 250mm / min, 300mm / min, 500mm / min, seven test speeds) to the sample, and the sample is pierced. Whether the battery has electric breakdown and thermal breakdown is observed by a Leica microscope, and the results are shown in Table 1.

[0059] Table 1

[0060]

[0061] As can be seen from Table 1, the explosion-proof battery of Examples 1-3 did not have the phenomenon of electric breakdown and thermal breakdown when the puncture test was carried out at -60℃-200℃, which shows that in Examples 1-3, the viscous liquid rubber coated around the battery cell can block the path formed by the contact of the puncture needle with the inside of the battery cell, and avoid short circuit and thermal runaway of the battery, so the phenomenon of electric breakdown and thermal breakdown does not occur during the puncture process.

[0062] In summary, the explosion-proof battery provided by the present application can effectively prevent the battery from short circuiting and eliminate the risk of self-ignition of the battery.

[0063] The above examples are only preferred examples for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation made by those skilled in the art on the basis of the present application is within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. An explosion-proof battery, characterized by comprising: The battery comprises: a battery shell, a battery cell accommodated in the battery shell; and a wrapping layer covering the surface of the battery cell, the wrapping layer comprising a sealed shell having a sandwich cavity filled with viscous insulating liquid. The viscous insulating liquid comprises the following components by weight: 107 silicone rubber 100 parts, gum rosin tackifier 5-8 parts, TOTM 1-3 parts, diphenylsilanediol 1.5 parts. The viscosity of the viscous insulating liquid at 25°C is 1500-2000 mPa·s. The viscous insulating liquid has a viscosity of 1000 to 2000 mPa-s at 25°C, and the viscous insulating liquid has a volume resistivity of at least 1.0 x 10 14 Ω-cm.

2. The explosion-proof battery according to claim 1, characterized in that The sealed shell is a sealed bag body.

3. The explosion-proof battery of claim 1, wherein The sealed bag body is a polytetrafluoroethylene bag body.

4. The explosion-proof battery according to claim 3, wherein The wrapping layer covers at least the top surface, bottom surface and side surface of the battery cell.

5. The explosion-proof battery of claim 1, wherein The battery cell is a plurality of battery cells, and the plurality of battery cells are arranged in a stack to form an integrated body; the wrapping layer covers the surface of the integrated body.

6. The explosion-proof battery of claim 1, wherein The battery cell is a plurality of battery cells, and the wrapping layer covers the surface of each battery cell.

7. The explosion-proof battery of claim 1, wherein The battery comprises a plurality of the explosion-proof battery according to any one of claims 1-7.

8. A battery pack, characterized by, The battery pack comprises the battery according to claim 8.

9. An electric device, characterized by ​

Images