Battery and battery pack

Abstract

The utility model relates to a battery and a battery pack. The battery comprises a battery cell and two shells, each shell comprises a polypropylene layer positioned on the inner layer and a steel layer positioned on the outer layer, and a sunken part is formed at the steel layer; the concave parts of the respective steel layers of the two shells are aligned, and the concave openings are opposite to each other, so that an assembly space for assembling the core is formed; the polypropylene layers of the two shells are oppositely arranged, the extension parts of the two shells are attached and sealed, and a resectable air bag is formed between the extension parts of the two shells. The shell of the battery is only provided with a two-layer structure, namely a polypropylene layer and a steel layer, so that the available space in the battery can be effectively improved. Moreover, welding sealing is not adopted, but the polypropylene layers of the two shells are used for sealing connection, so that the problems of explosion welding and welding omission caused by steel shell welding are avoided. And meanwhile, in the formation process, the gas bag can accommodate the generated gas, so that the damage of the gas to the battery structure is avoided.

Description

Technical Field

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

[0002] Currently, the aluminum-plastic film of batteries typically consists of an outer barrier layer, two adhesive layers, an aluminum foil layer, and a heat-sealing layer. The outer barrier layer is usually a nylon layer, which is used to protect the middle aluminum foil layer from scratches and prevent air penetration, as well as to ensure the thermal stability of the aluminum foil. The aluminum foil has a certain strength to protect the internal core of the battery cell and prevent moisture penetration. The heat-sealing layer is usually a polypropylene film, which is used for insulation and sealing.

[0003] However, the outer barrier layer and aluminum foil layer in the aluminum-plastic film of the battery can both prevent air or moisture, and their protective effects are redundant. In addition, they also limit the internal volume, reduce the internal space, and reduce the battery capacity. Furthermore, the battery casing is usually sealed by welding process. Welding thin steel casings can easily lead to problems such as casing explosion and leakage, which need to be improved. Utility Model Content

[0004] In order to overcome at least one of the defects described in the prior art, according to one aspect of the present invention, a battery is provided, including a cell and two housings; each housing includes a polypropylene layer located in an inner layer and a steel layer located in an outer layer, and a recess is formed in the steel layer, and the polypropylene layer has an inner layer portion fixed in the recess of the steel layer and an outer extension portion located outside the steel layer.

[0005] The recesses of the steel layers of the two housings are aligned and face each other to form an assembly space for assembling the power supply core.

[0006] The two shells have polypropylene layers facing each other, and their respective extension portions are fitted and sealed together, with the extension portions forming a removable air bag.

[0007] In one embodiment of this application, at least one outer side of the recessed portion of the steel layer of the shell is provided with an extension segment, the length L1 of which is ≥1mm;

[0008] Within the same housing, the extended portion of the polypropylene layer abuts against the extended portion of the steel layer.

[0009] In one embodiment of this application, the length L2 of the extended portion after the steel layer of the shell and the polypropylene layer are cut off is ≥0.1mm, and the extended portion is sealed.

[0010] In one embodiment of this application, the two housings are symmetrically arranged and cover each other.

[0011] In one embodiment of this application, the extended portions of the polypropylene layers of each of the two housings are thermo-sealed.

[0012] In one embodiment of this application, the battery cell has a positive tab and a negative tab, both of which are welded to the sidewalls of the steel layers of the two housings respectively.

[0013] In one embodiment of this application, the two housings are stamped.

[0014] In one embodiment of this application, the two shells are either square half-shells or cylindrical half-shells.

[0015] In one embodiment of this application, the polypropylene layer and the steel layer of the housing may be bonded together specifically by an adhesive.

[0016] According to another aspect of this application, a battery pack is provided, including one of the batteries described above.

[0017] In summary, the battery and battery pack provided by this utility model have the following technical effects:

[0018] The battery casing has only two layers: a polypropylene layer and a steel layer. This replaces the existing three-layer structure of aluminum-plastic film (nylon layer, aluminum foil layer, and polypropylene film layer) in batteries. This is equivalent to reducing the nylon layer of the existing aluminum-plastic film structure and directly using the steel layer as the outer shell, which can effectively increase the usable space inside the battery and provide more internal space for battery capacity design.

[0019] Furthermore, since the shell is made of one layer of polypropylene and one layer of steel, the shell is relatively thin. This application does not use welding for sealing, but uses the polypropylene layers of the two shells to seal and connect them, so as to avoid the problems of weld explosion and weld leakage caused by welding the steel shell.

[0020] Meanwhile, during the formation process, the gas bag can contain the generated gas, preventing it from damaging the battery structure. After formation, the gas bag can be removed, allowing for a more compact overall battery structure, reducing unnecessary space occupation, and increasing the battery's energy density. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a battery in an exploded state according to an embodiment of the present invention.

[0022] Figure 2 This is a cross-sectional view of the internal structure of a battery according to an embodiment of the present utility model;

[0023] Figure 3 This is a cross-sectional view of the internal structure of a battery after the outer extension of the steel layer and the outer extension of the polypropylene layer have been removed, according to an embodiment of the present invention.

[0024] Attached Figure: 1-Battery cell, 11-Positive tab, 12-Negative tab, 2-Shell, 21-Polypropylene layer, 211-Inner layer, 212-Outer layer, 22-Steel layer, 3-Air bag. Detailed Implementation

[0025] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0026] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0027] 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 invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0028] To better understand the inventive concept of this utility model, let's first describe the problems encountered in practice.

[0029] Since the existing battery casing 2 has an external barrier layer and an aluminum foil layer that can prevent air or moisture, the protective functions of the two are redundant. The presence of both will undoubtedly limit the internal volume, reduce the internal space, and reduce the battery capacity.

[0030] Therefore, please refer to Figures 1-3 This utility model discloses a battery, which specifically includes a cell 1 and two housings 2. Each housing 2 includes an inner polypropylene layer 21 and an outer steel layer 22, and a recess is formed in the steel layer 22. The polypropylene layer 21 has an inner layer portion 211 fixed in the recess of the steel layer 22 and an outer extension portion 212 located outside the steel layer 22. The recesses of the steel layers 22 of the two housings 2 are aligned and the notches face each other to form an assembly space for assembling the cell 1. The polypropylene layers 21 of the two housings 2 are arranged facing each other, and their respective outer extension portions 212 are fitted and sealed, and a severable air bag 3 is formed between the respective outer extension portions 212.

[0031] Therefore, the battery casing has only two layers: a polypropylene layer 21 and a steel layer 22. This replaces the existing three-layer structure of the aluminum-plastic film (nylon layer, aluminum foil layer, and polypropylene film layer) in batteries. This effectively reduces the nylon layer of the existing aluminum-plastic film structure, directly using the steel layer 22 as the outer shell. This significantly increases the usable internal space of the battery, providing more space for battery capacity design. Furthermore, the steel layer 22, specifically a steel foil layer, has higher impact resistance, providing stronger protection against external damage and deformation.

[0032] After designing the battery casing 2 with a polypropylene layer 21 and a steel layer 22, it was found during welding that the casing 2 was prone to weld failure due to its relatively thinness.

[0033] Therefore, this application does not employ welding for sealing, but instead utilizes the polypropylene layers 21 of each of the two housings 2 for sealing connection, thereby avoiding problems such as weld explosions and leaks caused by welding thin steel shells. Furthermore, the polypropylene layers 21 of each of the two housings 2 effectively prevent moisture and air from entering the assembly space, protecting the battery cell 1.

[0034] After sealing and connecting the two casings 2 using their respective polypropylene layers 21, it was discovered that a gas bag 3 was cleverly formed between the extended portions 212 of the polypropylene in each of the two casings 2 to facilitate venting during the subsequent formation process. This gas bag 3 was then removed after formation. During battery formation, some gases are generated and accumulate in the gas bag 3. After formation, the gas bag 3 is removed and then resealed to ensure a more compact and stable overall battery structure.

[0035] This design allows the gas bag 3 to contain the generated gases during the formation process, preventing damage to the battery structure. After formation, the gas bag 3 can be removed, resulting in a more compact battery structure, reduced unnecessary space occupation, and increased energy density. Furthermore, the presence of the gas bag 3 provides a specific emission area for the gases generated during formation, helping to control gas distribution and pressure, and improving the stability and safety of the formation process.

[0036] Specifically, the extended portions 212 of the polypropylene layers 21 of each of the two housings 2 are heat-sealed. This avoids problems caused by welding, reduces process costs, and lowers manufacturing costs.

[0037] Specifically, the two casings 2 are stamped together. Stamping is a highly efficient forming method that can process sheet metal into the required casing 2 shape in a short time. Compared with other manufacturing methods, stamping has a faster production speed, meeting the needs of large-scale production. Furthermore, stamping has high production efficiency, allowing for the rapid production of large quantities of casings 2 of the same specifications. This enables battery manufacturers to meet market demand for different battery models, improving the market competitiveness of their products.

[0038] Specifically, at least one outer side of the recessed portion of the steel layer 22 of the housing 2 has an extended section, the length of which L1 ≥ 1 mm. Within the same housing 2, the extended portion 212 of the polypropylene layer 21 abuts against the extended section of the steel layer 22. This arrangement ensures a tighter seal when the polypropylene layers 21 of the two housings 2 are sealed together. This abutment reduces gaps at the seal, preventing moisture, air, and other impurities from entering the battery, thus improving the battery's sealing performance and extending its lifespan. Furthermore, during manufacturing, the presence of the extended section of the steel layer 22 provides a clear positioning reference for the installation of the polypropylene layer 21, making installation easier and more accurate, improving production efficiency and product quality.

[0039] Specifically, the length L1 of the epitaxial segment can be 1mm ≤ L1 ≤ 2m. For example, the length L1 of the epitaxial segment can be 1mm, 50mm, 1m, 1.5m, or 2mm. Of course, the length L1 of the epitaxial segment can also be other values ​​within the range of 1mm ≤ L1 ≤ 2m. With this setting, the epitaxial segment within this size range can provide sufficient support for the epitaxial portion 212 of the polypropylene layer 21 for better sealing. At the same time, the length of the epitaxial segment of 1mm to 2m is relatively easy to control during manufacturing and assembly, so that it is neither too short and difficult to achieve effective support and sealing, nor too long and increases manufacturing difficulty and cost.

[0040] Specifically, the length L2 of the extended portion after the steel layer 22 of the shell 2 and the extended portion 212 of the polypropylene layer 21 are removed is ≥0.1mm, and the extended portion is sealed.

[0041] In the actual manufacturing process, since the steel layer 22 of the shell 2 has an extended section and the polypropylene layer 21 also has a corresponding extended portion 212, in a specific manufacturing or assembly stage, such as after formation, the gas will gather in the air bag 3 formed between the extended portions 212 of the polypropylene layers 21 of the two shells. At this time, the air bag 3 needs to be cut off. The specific structure to be cut off is the extended section of the steel layer 22 and the extended portion 212 of the polypropylene layer 21, but a certain length of extended portion will be retained, with a length L2≥0.1mm. This retained extended portion will be sealed in subsequent processes.

[0042] The sealing of the extended portion with a length of L2 can typically be achieved through methods such as thermoforming or bonding. These sealing methods isolate this extended portion from the external environment, ensuring the battery's internal airtightness.

[0043] Specifically, the length L2 of the extended portion after removal can be 0.1mm ≤ L2 ≤ 500m. For example, the length L2 of the extended portion after removal can be 0.1mm, 1mm, 10mm, 100mm, or 500m. Of course, the length L2 of the extended portion after removal can also be other values ​​within the range of 0.1mm ≤ L2 ≤ 500m. This size range allows for precise length control of the extended portion after removal, making the design of the battery casing 2 more flexible. It can be adjusted according to different application requirements and space constraints, allowing for the selection of a suitable L2 length to meet specific structural requirements, whether for small electronic devices or large energy storage systems. Furthermore, this size range facilitates operation and control during the production process, making it easier to achieve accurate removal lengths whether using mechanical cutting or other processing methods. At the same time, the sealing process can also be optimized based on the length of L2, improving production efficiency and product quality.

[0044] Specifically, the battery cell 1 has a positive tab 11 and a negative tab 12, which are welded one-to-one to the sidewalls of the steel layers 22 of the two housings 2.

[0045] In actual manufacturing, the positive tab 11 and negative tab 12 of the battery cell 1 are welded to the sidewalls of the steel layer 22 of each of the two housings 2. This welding connection ensures good electrical conductivity, allowing the electricity generated inside the battery cell 1 to be smoothly transmitted through the tabs to the steel layer 22 of the housing 2, and then further transmitted to the external circuit. This arrangement, welding the tabs to the sidewalls of the steel layer 22 of the housing 2, makes full use of the side space of the housing 2, avoiding a cluttered distribution of the tabs inside the housing 2, resulting in a more compact battery structure. This is particularly important for miniaturized and thinner electronic devices, enabling higher energy density within a limited space.

[0046] It should be noted that since the polypropylene layer 21 of the shell 2 is located in the inner layer and the steel layer 22 is located in the outer layer, the polypropylene layer 21 needs to be removed at the welding position to expose the steel layer 22 for welding. The removal can be done by melting with a laser, and then the tabs are welded.

[0047] Specifically, the two casings 2 are square half-shells. This design allows for efficient layout and assembly within a limited space. The size and internal structure of the square half-shells can be rationally designed according to the size and shape of the battery cell 1 to maximize space utilization. This optimized space utilization can improve the battery's energy density, meaning that more battery cell 1 material can be accommodated in the same volume, thereby increasing the battery's capacity and performance. Furthermore, the square half-shell structure is relatively simple, easy to manufacture and process, and can be produced using processes such as stamping and injection molding, improving production efficiency and reducing costs.

[0048] In other embodiments, the two shells 2 are cylindrical half-shells. This configuration results in a relatively simple cylindrical half-shell structure, which is easy to manufacture and process. The steel layer 22 can be efficiently produced using processes such as stamping and stretching, while the polypropylene layer 21 can be bonded to the steel layer 22 through injection molding, hot pressing, or other methods. This simplicity in manufacturing helps improve production efficiency and reduce production costs. Furthermore, the consistency of the cylindrical shape facilitates automated production and quality control.

[0049] Specifically, the two shells 2 are symmetrically arranged and fit together perfectly. This arrangement ensures that the two shells 2 are symmetrically designed in shape and size, allowing them to fit together seamlessly. Furthermore, the symmetrical design of the shells 2 simplifies and improves the manufacturing process. During manufacturing, the same molds and processes can be used to produce both shells 2, reducing production costs. Simultaneously, the symmetrical structure facilitates assembly; workers can more easily align and connect the two shells 2, improving production efficiency. In addition, the symmetrical design facilitates quality control, as the consistency of the two shells 2 is easier to guarantee, reducing assembly problems caused by dimensional deviations or asymmetry.

[0050] Specifically, the polypropylene layer 21 and the steel layer 22 of the shell 2 can be bonded together using an adhesive. During the manufacturing process of the shell 2, the polypropylene layer 21 and the steel layer 22 are connected using a specific adhesive. This arrangement, through the action of the adhesive, makes the bond between the polypropylene layer 21 and the steel layer 22 stronger, which improves the overall strength and stability of the shell 2, enabling it to better withstand external forces such as pressure, impact, and vibration.

[0051] The adhesive can be selected from hot melt adhesives, two-component polyurethane adhesives, acrylic adhesives, or epoxy adhesives, etc.

[0052] This utility model also discloses a battery pack, including the aforementioned battery. It is understood that the battery casing 2 of this battery pack has only two layers: a polypropylene layer 21 and a steel layer 22, replacing the existing three-layer structure of the aluminum-plastic film (nylon layer, aluminum foil layer, and polypropylene film layer). This effectively reduces the nylon layer of the existing aluminum-plastic film structure, directly using the steel layer 22 as the outer shell, thus effectively increasing the usable internal space of the battery and providing more internal space for battery capacity design. Simultaneously, instead of welding for sealing, the two casings 2 are sealed together using their respective polypropylene layers 21, avoiding the problems of weld explosions and leaks caused by steel shell welding. Furthermore, the two casings 2's respective polypropylene layers 21 effectively prevent moisture and air from entering the assembly space, protecting the battery cell 1. Moreover, after formation, the air bag 3 can be removed, making the overall battery structure more compact, reducing unnecessary space occupation, and increasing the battery's energy density. Furthermore, the presence of the gas bag 3 provides a specific emission area for the gas during the formation process, which helps to control the gas distribution and pressure, and improves the stability and safety of the formation process.

[0053] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A battery, characterized in that, It includes a battery cell (1) and two housings (2); each housing (2) includes an inner polypropylene layer (21) and an outer steel layer (22), and a recess is formed in the steel layer (22), and the polypropylene layer (21) has an inner portion (211) fixed in the recess of the steel layer (22) and an outer extension portion (212) located outside the steel layer (22); The recesses of the steel layers (22) of the two housings (2) are aligned and face each other to form an assembly space for assembling the power supply core (1); The polypropylene layers (21) of the two shells (2) are arranged facing each other, and their respective extension portions (212) are fitted and sealed together, and the extension portions (212) are used to form a removable air bag (3).

2. The battery according to claim 1, characterized in that, At least one outer side of the recess of the steel layer (22) of the shell (2) is provided with an extension segment, the length of the extension segment L1≥1mm; Within the same housing (2), the extended portion (212) of the polypropylene layer (21) abuts against the extended portion of the steel layer (22).

3. A battery according to claim 2, characterized in that, The length L2 of the extended portion after the steel layer (22) of the shell (2) and the extended portion (212) of the polypropylene layer (21) are removed is ≥0.1mm, and the extended portion is sealed.

4. A battery according to any one of claims 1-3, characterized in that, The two housings (2) are symmetrically arranged and cover each other.

5. A battery according to any one of claims 1-3, characterized in that, The extension portion (212) of the polypropylene layer (21) of each of the two housings (2) is thermo-sealed.

6. A battery according to any one of claims 1-3, characterized in that, The battery cell (1) has a positive tab (11) and a negative tab (12), and the positive tab (11) and the negative tab (12) are welded to the sidewalls of the steel layers (22) of the two housings (2) respectively.

7. A battery according to any one of claims 1-3, characterized in that, The two housings (2) are stamped together.

8. A battery according to any one of claims 1-3, characterized in that, The two shells (2) are either square half-shells or cylindrical half-shells.

9. A battery according to any one of claims 1-3, characterized in that, The polypropylene layer (21) and the steel layer (22) of the shell (2) can be bonded together by an adhesive.

10. A battery pack, characterized in that, Includes a battery according to any one of claims 1-9.

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