Cylindrical battery shell and cylindrical battery

Abstract

The utility model provides a cylindrical battery shell and a cylindrical battery, and relates to the technical field of batteries, the cylindrical battery shell comprises a metal shell and an elastic layer arranged on the inner wall of the metal shell, and the elastic layer is configured to generate plastic deformation when being punctured and tightly wrap a punctured object so as to seal a gap between the punctured object and the metal shell. By arranging the elastic layer on the inner wall of the metal shell, the elastic layer can deform and tightly wrap a puncture object due to the elasticity and plasticity of the elastic layer under the needling condition, so that high-temperature and high-pressure gas in the battery is prevented from being sprayed out from a puncture hole at a high speed, and the risk that the gas brings out flames or high-temperature substances is reduced; and high-pressure gas in the cylindrical battery is directionally discharged from the anti-explosion valve. According to the structure arrangement, the possibility of battery combustion is reduced, particularly in a multi-battery module, the heat spreading risk caused by failure of one battery can be reduced, and the overall safety performance of the cylindrical battery is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cylindrical battery casing and a cylindrical battery. Background Technology

[0002] Cylindrical lithium-ion batteries are widely used in electric vehicles, energy storage systems, and medical devices due to their advantages such as small size, high energy density, and long cycle life. Currently, the casing of cylindrical batteries typically uses a single- or double-through rigid pure aluminum or pure steel ring structure, with the positive and negative electrode sheets arranged in a ring-wound manner inside. However, this structure has significant defects in safety testing, such as the nail penetration test.

[0003] First, because the internal electrodes are curved and wound together, the probability of a short circuit during a needle puncture is much higher than in a square battery with a planar structure. The short circuit point generates severe localized heat, easily leading to thermal runaway. Second, the rigid casing is prone to cracking or gaps after being punctured, preventing the high-temperature, high-pressure gas inside the battery from being released through the designed safety relief channels (such as the explosion-proof valve on the cover). Instead, the gas escapes from the puncture site. Due to the extremely high temperature at the puncture point, the ejected gas often ignites, causing the battery to burn.

[0004] More seriously, in module applications, the needle-piercing flame from a single cylindrical battery can directly ignite adjacent batteries, causing heat spread and threatening the safety of the entire battery system. Utility Model Content

[0005] In view of this, the present invention proposes a cylindrical battery casing and a cylindrical battery to solve the problems of uncontrollable pressure relief path and easy emission of high-temperature gas from the puncture hole during the needle puncture of existing cylindrical batteries, which leads to the spread of combustion.

[0006] The technical solution of this utility model is implemented as follows:

[0007] On the one hand, the present invention provides a cylindrical battery casing, including a metal outer shell and an elastic layer disposed on the inner wall of the metal outer shell. The elastic layer is configured to undergo plastic deformation and tightly wrap the punctured object when punctured, so as to seal the gap between the punctured object and the metal outer shell.

[0008] Based on the above technical solution, preferably, the elastic layer is made of silicone rubber, fluororubber, or thermoplastic polyurethane elastomer material.

[0009] Based on the above technical solution, preferably, the melting point of the elastic layer is not lower than 250°C.

[0010] Based on the above technical solution, preferably, the elastic layer and the metal shell are further provided with a connecting layer, and the elastic layer is fixed to the inner wall of the metal shell through the connecting layer.

[0011] Based on the above technical solution, preferably, the connecting layer is a high-temperature resistant adhesive layer, and the melting point of the connecting layer is higher than that of the elastic layer.

[0012] Based on the above technical solution, preferably, the high-temperature resistant adhesive layer is at least one of modified epoxy resin adhesive, polyimide adhesive, and inorganic-organic hybrid adhesive.

[0013] Based on the above technical solution, preferably, the connecting layer contains 5-15 wt% of nano-ceramic filler, and the particle size of the nano-ceramic filler is 20-100 nm.

[0014] Based on the above technical solution, preferably, the thickness of the connecting layer is 0.01 to 0.5 mm, and the thickness of the elastic layer is 0.1 to 2 mm.

[0015] Based on the above technical solution, preferably, the material of the metal shell is aluminum, copper, stainless steel or alloy steel.

[0016] Secondly, this utility model also discloses a cylindrical battery, including the cylindrical battery casing described in the first aspect.

[0017] The present invention has the following advantages over the prior art:

[0018] (1) By setting an elastic layer on the inner wall of the metal casing, in the event of a needle puncture, the elastic layer deforms due to its elasticity and plasticity, tightly wrapping the punctured object and preventing high-temperature, high-pressure gas inside the battery from being ejected at high speed from the puncture hole. This reduces the risk of gas carrying out flames or high-temperature substances, allowing the high-pressure gas inside the cylindrical battery to leak out directionally from the explosion-proof valve. This structural design reduces the possibility of battery combustion, especially in multi-battery modules, reducing the risk of heat spread caused by the failure of a single battery and improving the overall safety performance of the cylindrical battery.

[0019] (2) By setting a high-temperature resistant adhesive layer between the metal shell and the elastic layer, it is possible to ensure that the bonding strength can be maintained under thermal runaway conditions, and to avoid the peeling of the elastic layer and the metal shell.

[0020] (3) By adding nano-ceramic fillers to the connecting layer, more physical and chemical bonds can be formed between the connecting layer and the substrate, improving the interfacial bonding force and enhancing the overall structure’s robustness and stability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a three-dimensional structural diagram of the cylindrical battery casing disclosed in this utility model;

[0023] Figure 2 This is a schematic diagram of the planar structure of the cylindrical battery casing disclosed in this utility model;

[0024] Figure label:

[0025] 1. Metal outer shell; 2. Elastic layer; 3. Connecting layer. Detailed Implementation

[0026] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0027] like Figure 1 As shown, combined with Figure 2 This utility model discloses a cylindrical battery casing, including a metal outer shell 1 and an elastic layer 2.

[0028] The metal casing 1 is the main structural component of the cylindrical battery, providing mechanical strength and basic protection. In some embodiments, the metal casing 1 is made of aluminum, copper, stainless steel or alloy steel to ensure the robustness and durability of the casing.

[0029] The elastic layer 2 is located on the inner wall of the metal casing 1. The material selected is usually a material with a certain elasticity and plastic deformation ability. The function of the elastic layer 2 is that when the cylindrical battery is punctured by a needle and the puncture object pierces the elastic layer 2, the elastic layer 2 will deform due to its elasticity and plasticity and tightly wrap the puncture object to seal the gap between the puncture object and the metal casing 1, so as to prevent the internal short circuit of the battery from causing thermal runaway and the high temperature and high pressure gas generated from leaking through the puncture hole.

[0030] The sealing effect of the elastic layer 2 prevents internal gas from being ejected at high speed from the puncture hole in the event of a needle puncture, thus reducing the risk of gas carrying flames or high-temperature substances. This allows the high-pressure gas inside the cylindrical battery to leak out directionally through the explosion-proof valve. This structural design reduces the possibility of battery combustion, especially in multi-cell modules, reducing the risk of heat spread caused by the failure of a single cell and improving the overall safety performance of the cylindrical battery.

[0031] In some embodiments, the elastic layer 2 is made of silicone rubber, fluororubber, or thermoplastic polyurethane elastomer material.

[0032] Silicone rubber possesses excellent high-temperature stability, chemical corrosion resistance, and electrical insulation. This allows it to withstand high-temperature environments during battery operation while remaining resistant to corrosion by electrolytes or other chemicals. The flexibility and elasticity of silicone rubber enable it to effectively deform and seal the puncture site when the battery is punctured, ensuring a tight fit with the metal casing and preventing internal gas leakage.

[0033] Fluororubber possesses extremely high chemical resistance and high-temperature resistance, enabling it to maintain its physical properties in harsh environments. Its oil and fuel resistance makes it particularly suitable for battery environments containing organic solvents, ensuring effective sealing of the puncture site even in the event of a puncture.

[0034] Thermoplastic polyurethane elastomers have good mechanical properties, including high abrasion resistance, high elasticity and good tear resistance, which enables them to quickly recover and seal the puncture site when the battery is punctured.

[0035] In some implementations, the melting point of the elastic layer 2 is not lower than 250°C. By setting the melting point of the elastic layer 2, it is ensured that the elastic layer 2 remains solid within the normal operating temperature range of the battery, and sufficient thermal stability can also be provided when the temperature is between 150°C and 250°C due to internal thermal runaway caused by a needle puncture in the cylindrical battery.

[0036] In some implementations, in order to fix the elastic layer 2 and the inner wall of the metal shell 1, this embodiment also provides a connecting layer 3 between the elastic layer 2 and the metal shell 1.

[0037] In some embodiments, the connecting layer 3 is a high-temperature resistant adhesive layer, and the melting point of the connecting layer 3 is higher than that of the elastic layer 2. In this embodiment, the melting point of the connecting layer 3 should be higher than 300°C to ensure that the bonding strength can be maintained in the event of thermal runaway.

[0038] As some embodiments, the high-temperature resistant adhesive layer is at least one of modified epoxy resin adhesive, polyimide adhesive, and inorganic-organic hybrid adhesive.

[0039] Modified epoxy resin, polyimide, or inorganic-organic hybrid adhesives are used. These materials themselves possess excellent high-temperature resistance, enabling the battery casing to operate without failure in high-temperature environments, ensuring battery safety and performance stability. These adhesives all have good bonding strength, ensuring a firm bond between the various parts of the battery casing and preventing delamination or detachment due to mechanical vibration or thermal cycling during use.

[0040] These adhesives can be used alone or in combination, and can be optimized according to specific application requirements to achieve the best overall performance. For example, in some extreme environments, using a combination of multiple adhesives can simultaneously meet the requirements of high heat resistance and high bond strength.

[0041] In some embodiments, the connecting layer 3 comprises 5-15 wt% nano-ceramic filler with a particle size of 20-100 nm. The addition of nano-ceramic filler can significantly improve the mechanical properties of the connecting layer 3, including tensile strength, compressive strength, and toughness. Ceramic materials themselves have high strength and high hardness, and nano-scale fillers can effectively fill defects in the matrix material, enhancing the overall strength and toughness of the structure.

[0042] The addition of nano-ceramic fillers significantly improves the mechanical properties of the connecting layer 3, including tensile strength, compressive strength, and toughness. Ceramic materials themselves possess high strength and hardness, and nano-scale fillers can effectively fill defects in the matrix material, enhancing the overall strength and toughness of the structure. Due to their high specific surface area and surface energy, nano-ceramic fillers can form more physical and chemical bonds between the connecting layer 3 and the substrate, improving interfacial adhesion and enhancing the overall structural robustness and stability.

[0043] In some implementations, the thickness of the connecting layer 3 is 0.01–0.5 mm. This range ensures that the connecting layer 3 provides sufficient adhesive strength and stability without significantly increasing the overall thickness or weight of the battery casing. The thickness of the elastic layer 2 is 0.1–2 mm. This range provides sufficient cushioning and elasticity to cope with the mechanical stress and deformation generated during battery use.

[0044] This invention also provides a cylindrical battery, including the cylindrical battery casing disclosed in the above embodiments. By using the cylindrical battery casing disclosed in the above embodiments, when the cylindrical battery is punctured, the elastic layer 2 can wrap around the puncturing object, preventing the internal gas of the battery from being ejected at high speed from the puncture hole, thereby reducing the risk of the gas carrying out flames or high-temperature substances, and allowing the high-pressure gas inside the cylindrical battery to be released directionally from the explosion-proof valve. This structural design reduces the possibility of battery combustion, especially in multi-battery modules, reducing the risk of heat spread caused by the failure of one battery, and improving the safety of the cylindrical battery and battery module.

[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A cylindrical battery case characterized by: The metal shell (1) and the elastic layer (2) arranged on the inner wall of the metal shell (1), the elastic layer (2) is configured to plastically deform and tightly wrap the puncture object when being punctured to seal the gap between the puncture object and the metal shell (1).

2. The cylindrical battery case according to claim 1, wherein: The elastic layer (2) is made of silicone rubber, fluororubber or thermoplastic polyurethane elastomer material.

3. The cylindrical battery case according to claim 1, wherein: The melting point of the elastic layer (2) is not less than 250 DEG C.

4. The cylindrical battery case according to claim 1, wherein: The elastic layer (2) and the metal shell (1) are further provided with a connecting layer (3), and the elastic layer (2) is fixed to the inner wall of the metal shell (1) through the connecting layer (3).

5. The cylindrical battery case according to claim 4, wherein: The connecting layer (3) is a high-temperature-resistant adhesive layer, and the melting point of the connecting layer (3) is higher than that of the elastic layer (2).

6. The cylindrical battery case according to claim 5, wherein: The high-temperature-resistant adhesive layer is at least one of modified epoxy resin adhesive, polyimide adhesive and inorganic-organic hybrid adhesive.

7. The cylindrical battery case according to claim 5, wherein: The connecting layer (3) contains 5-15 wt% of nano ceramic filler, and the particle size of the nano ceramic filler is 20-100 nm.

8. The cylindrical battery case according to claim 4, wherein: The thickness of the connecting layer (3) is 0.01-0.5 mm, and the thickness of the elastic layer (2) is 0.1-2 mm.

9. The cylindrical battery case according to claim 1, wherein: The metal shell (1) is made of aluminum, copper, stainless steel or alloy steel.

10. A cylindrical battery characterized by comprising: The cylindrical battery shell comprises the cylindrical battery shell according to any one of claims 1-9.

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