Battery and battery pack

Abstract

The utility model relates to a battery and a battery pack. The battery comprises two shells arranged in a covering manner and a battery cell arranged between the two shells, each shell comprises a polypropylene layer and a steel layer, and the two shells are connected in a sealed mode through the respective polypropylene layers. 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, and more internal space is provided for the capacity design of the battery. 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. Meanwhile, the covering structure is utilized, sealing of the polypropylene layer is combined, the assembling space formed by the covering structure can more flexibly accommodate the battery cell, the space layout is optimized, the energy density of the battery is improved, the battery is easy to assemble and produce, and the manufacturing difficulty and cost are reduced.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery and a 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, comprising two housings disposed in a cover configuration and a battery cell disposed between the two housings.

[0005] Each of the housings comprises a polypropylene layer and a steel layer, and the two housings are sealed together by their respective polypropylene layers.

[0006] In one embodiment of this application, the connection structure of the polypropylene layers of the two shells may specifically employ thermo-press sealing or adhesive sealing.

[0007] In one embodiment of this application, the two housings are vertically fitted together, one of the housings includes an inner polypropylene layer and an outer steel layer, and the other housing includes an inner steel layer and an outer polypropylene layer.

[0008] The inner side of the polypropylene layer of the inner layer of one of the housings is sealed to the outer side of the polypropylene layer of the outer layer of the other housing.

[0009] In one embodiment of this application, the two shells are square half-shells, and the length and width of one shell are both greater than the length and width of the other shell.

[0010] Alternatively, both shells may be cylindrical half-shells, with the diameter of one shell being larger than the diameter of the other shell.

[0011] In one embodiment of this application, when the two housings are closed, the steel layer of each of the two housings is used for magnetic conduction, and the polypropylene layer of each of the two housings is heat-pressed sealed.

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

[0013] In one embodiment of this application, one of the positive and negative tabs is welded to the inner top wall of the steel layer of the shell of one of the tabs, and the other is welded to the inner bottom wall of the steel layer of the shell of the other.

[0014] In one embodiment of this application, the two housings are stamped.

[0015] In one embodiment of this application, the two housings are configured without injection holes.

[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, this application does not use welding for sealing, but instead uses the polypropylene layers of the two shells to seal and connect them, thereby avoiding the problems of weld explosion and leakage caused by welding the steel shell.

[0020] Meanwhile, in order to accelerate production efficiency, this application also utilizes a cover structure combined with the sealing of a polypropylene layer. The assembly space formed by this cover structure can more flexibly accommodate battery cells, optimize spatial layout, improve battery energy density, and is easy to assemble and produce, reducing manufacturing difficulty and cost. 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] Attached diagram: 1-shell, 11-polypropylene layer, 12-steel layer, 2-cell, 21-positive tab, 22-negative tab. Detailed Implementation

[0024] 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.

[0025] 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.

[0026] 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.

[0027] To better understand the inventive concept of this utility model, let's first describe the problems encountered in practice.

[0028] Since the existing battery casing 1 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.

[0029] Therefore, please refer to Figure 1 and Figure 2 The present invention discloses a battery, which specifically includes two housings 1 that are covered together and a battery cell 2 disposed between the two housings 1. Each housing 1 includes a polypropylene layer 11 and a steel layer 12. The two housings 1 are sealed together by their respective polypropylene layers 11.

[0030] Therefore, the battery casing 1 has only two layers: a polypropylene layer 11 and a steel layer 12, replacing the existing three-layer structure of the aluminum-plastic film (nylon layer, aluminum foil layer, and polypropylene film layer). This is equivalent to reducing the nylon layer of the existing aluminum-plastic film structure and directly using the steel layer 12 as the outer shell, which can effectively increase the usable space inside the battery, providing more internal space for battery capacity design. Furthermore, the steel layer 12, specifically a steel foil layer, has higher impact resistance and stronger protection against external damage and deformation.

[0031] The polypropylene layer 11 and the steel layer 12 of the shell 1 can be bonded together with an adhesive.

[0032] After designing the battery casing 1, which has a polypropylene layer 11 and a steel layer 12, it was found during welding that the casing 1 is relatively thin, which can easily lead to weld explosion during welding.

[0033] Therefore, this application does not employ welding for sealing, but instead uses the polypropylene layers 11 of each of the two housings 1 to seal and connect them, thus avoiding the problems of weld explosion and leakage caused by welding thin steel shells. Furthermore, the polypropylene layers 11 of each of the two housings 1 effectively prevent moisture and air from entering the assembly space, protecting the battery cell 2.

[0034] After sealing the two casings 1 together using their respective polypropylene layers 11, it was found that, in order to accelerate production efficiency, this application also utilizes a capping structure, combined with the sealing of the polypropylene layers 11, to provide good physical protection for the cell 2 and reduce the impact of external damage on the cell 2. More importantly, the assembly space formed by this capping structure can more flexibly accommodate the cell 2, optimize the spatial layout, and improve the energy density of the battery. Furthermore, the capping structure is relatively simple, easy to assemble and produce, and reduces manufacturing difficulty and cost.

[0035] Specifically, the connection structure of the polypropylene layers 11 of the two shells 1 can be sealed by hot pressing or by using adhesive, which can avoid the problems caused by welding thin steel shells and has a lower process cost.

[0036] In actual research and development, since the shell 1 includes a polypropylene layer 11 and a steel layer 12, in-depth design was carried out on how to assemble the polypropylene layer 11 and the steel layer 12 of the two shells 1 respectively.

[0037] For example, specifically, two housings 1 are vertically fitted together, one housing 1 includes an inner polypropylene layer 11 and an outer steel layer 12, and the other housing 1 includes an inner steel layer 12 and an outer polypropylene layer 11; the inner side of the inner polypropylene layer 11 of one housing 1 is sealed to the outer side of the outer polypropylene layer 11 of the other housing 1.

[0038] When the two housings 1 are closed, the inner surface of the inner polypropylene layer 11 of one housing 1 is in close contact with the outer surface of the outer polypropylene layer 11 of the other housing 1. Due to the good plasticity and sealing properties of polypropylene, a tight seal is formed between the two polypropylene layers 11 under appropriate pressure and temperature conditions. This seal effectively prevents external moisture, air, and impurities from entering the battery, protecting the battery cell 2 from external environmental influences and ensuring the normal operation and lifespan of the battery. Furthermore, the two housings 1 adopt a combination structure of steel layer 12 and polypropylene layer 11. When the steel layer 12 is located on the outer layer, it provides high strength and rigidity, protecting the battery cell 2 from external mechanical impacts and compression. When the polypropylene layer 11 is located on the inner layer, it forms a seal with the polypropylene layer 11 of the other housing 1 and also acts as insulation and buffer, reducing the risk of short circuits and damage that may occur inside the battery.

[0039] Specifically, the shell 1 comprising one of the inner polypropylene layer 11 and the outer steel layer 12 is the upper shell, and the other shell 1 comprising the inner steel layer 12 and the outer polypropylene layer 11 is the lower shell. In actual assembly, the opening of the upper shell is set downwards, and the opening of the lower shell is set upwards, with the upper shell covering the lower shell.

[0040] Of course, in other embodiments, the shell 1 including one of the inner polypropylene layer 11 and the outer steel layer 12 can be the lower shell, and the other shell 1 including the inner steel layer 12 and the outer polypropylene layer 11 can be the upper shell. In actual assembly, the shell opening of the upper shell is set downwards, the shell opening of the lower shell is set upwards, and the upper shell covers the lower shell.

[0041] In actual research and development, the shape of the shell 1 has several different structures. For example, specifically, the two shells 1 are square half-shells, and the length and width of one shell 1 are greater than the length and width of the other shell 1.

[0042] In this way, the larger shell 1 can be regarded as an outer cover, and the smaller shell 1 can be nested inside the larger shell 1. When the two shells 1 are closed, the edges of the smaller shell 1 are wrapped by the larger shell 1, forming a nesting doll-like structure. During the closing process, the inner surface of the larger shell 1 is in close contact with the outer surface of the smaller shell 1, especially in the polypropylene layer 11 of each shell 1, achieving a sealed connection through its good plasticity and sealing properties. This sealed connection can prevent external moisture, air, and impurities from entering the battery, protecting the internal battery cell 2. Furthermore, the size difference design allows the two shells 1 to form a relatively stable structure after closing. The support and fixation of the larger shell 1 on the smaller shell 1 enhances the battery's impact and compression resistance, reducing deformation and damage to the shells 1 caused by external forces during transportation and use. At the same time, the square shell 1 provides more internal space for the battery, which can accommodate larger battery cells 2 or other components, which helps to improve the battery's energy density and capacity, meeting the needs of different application scenarios.

[0043] For example, specifically, the two housings 1 are cylindrical half-shells, with the diameter of one housing 1 being larger than that of the other. This design, where the larger-diameter half-shell encloses the smaller-diameter half-shell, increases the sealing contact area and improves sealing reliability. This nested cylindrical structure better prevents the penetration of moisture, air, and impurities, extending battery life. Furthermore, the nested structure makes the connection between the two half-shells tighter, enhancing the overall structural strength of the battery. When subjected to external pressure, impact, or vibration, the larger-diameter half-shell can effectively disperse external forces, protecting the internal battery cells 2 and other components. Simultaneously, the cylindrical half-shell shape offers high space utilization, allowing more battery cell 2 material to be accommodated within a limited volume, thereby increasing the battery's energy density and capacity.

[0044] Specifically, when the two housings 1 are closed, the steel layer 12 of each housing 1 is used for magnetic conduction, and the polypropylene layer 11 of each housing 1 is heat-pressed to seal.

[0045] In this way, when the two shells 1 are closed, their respective steel layers 12 are magnetic. Under the influence of an external magnetic field, the steel layers 12 are magnetized, generating a certain magnetic attraction between the two shells 1. This magnetic force helps to tightly bond the two shells 1 together. At this time, the polypropylene layers 11 of the two shells 1 are sealed by hot pressing. Furthermore, the magnetic properties of the steel layers 12 can simplify the battery assembly process to a certain extent and improve production efficiency. For example, the magnetic force can be used to assist in the positioning and joining of the shells 1, reducing the difficulty and time of manual operation. At the same time, hot pressing sealing is a relatively simple and efficient sealing process. Hot pressing sealing does not require complex equipment and processes, and can quickly and accurately achieve sealing, thereby reducing manufacturing costs.

[0046] Specifically, the battery cell 2 has a positive tab 21 and a negative tab 22, which are welded one-to-one to the steel layers 12 of the two housings 1. During assembly, the positive and negative tabs 21 and 22 serve as bridges connecting the positive and negative active materials inside the battery cell 2 to the external circuit. When the battery cell 2 needs to be encapsulated in two housings 1, the positive and negative tabs 21 and 22 are welded to the steel layers 12 of the two housings 1 respectively. This configuration allows for a low-resistance current transmission path by welding the tabs to the steel layers 12, reducing energy loss during transmission. The high conductivity of the steel layers 12 ensures fast and stable current transmission from the battery cell 2 to the external circuit, improving the battery's charging and discharging efficiency and power output. Furthermore, welding the tabs to the steel layers 12 simplifies the battery manufacturing process. Compared to other connection methods, welding can be completed in a single operation, reducing assembly steps and process complexity, and improving production efficiency.

[0047] Specifically, one of the positive tab 21 and the negative tab 22 is welded to the inner top wall of the steel layer 12 of one of the housings 1, and the other is welded to the inner bottom wall of the steel layer 12 of the other housing 1. This arrangement, welding the tabs to the inner top and bottom walls of the steel layer 12 of the housing 1 respectively, makes full use of the internal space of the housing 1. This layout avoids a cluttered distribution of tabs inside the housing 1, making the battery structure more compact and facilitating higher energy density within a limited space. Furthermore, this clearly defined tab welding position design makes battery assembly more convenient and faster, allowing workers to accurately weld the tabs to the designated positions, reducing operational complexity and errors, and improving production efficiency and product quality.

[0048] It should be noted that, since the positive electrode tab 21 and the negative electrode tab 22 need to be welded to the steel layer 12 of each of the two shells 1 in a one-to-one correspondence, and since one shell 1 includes an inner polypropylene layer 11 and an outer steel layer 12, and the other shell 1 includes an inner steel layer 12 and an outer polypropylene layer 11, for the shell 1 with an inner polypropylene layer 11, the polypropylene layer 11 can be removed at the welding position by laser to form a welding area with a hollow area for welding.

[0049] Specifically, two shells 1 are stamped together. Stamping is a highly efficient forming method that can process sheet metal into the required shell 1 shape in a short time. Compared with other manufacturing methods, stamping has a faster production speed and can meet the needs of large-scale production.

[0050] Optionally, the two housings 1 can be designed without electrolyte injection holes. During battery assembly, a specific process can be used to pre-encapsulate the electrolyte inside the cell 2, or the electrolyte can be integrated with other components before the housing 1 is formed. This eliminates the need for subsequent electrolyte injection after battery assembly. Specifically, during the cell 2 manufacturing stage, a special process can be used to fully impregnate the electrode material with an appropriate amount of electrolyte. Then, the electrolyte-containing cell 2 is placed in the lower housing 1, and the housing 1 is then closed for sealing. Alternatively, advanced manufacturing technologies can be used, such as simultaneously wrapping the electrolyte around the cell 2 in a specific manner during the housing 1 forming process, achieving integrated electrolyte with other battery components. It should be noted that the design of the two housings 1 without electrolyte injection holes does not mean that electrolyte injection is unnecessary; it simply means that electrolyte is not injected through injection holes. Specifically, electrolyte can be injected into the housing before the lid is closed.

[0051] This design, eliminating the need for an electrolyte filling hole, reduces a potential weak point in the seal. Traditional batteries require additional sealing of the electrolyte filling hole, and regardless of the sealing method used, there is always a risk of leakage. The hole-less structure significantly improves the overall sealing performance of the battery, effectively preventing electrolyte leakage and the entry of external moisture, air, and other impurities into the battery, thereby extending battery life and improving its reliability and stability.

[0052] This utility model also discloses a battery pack, including the aforementioned battery. Therefore, the battery in this battery pack is not sealed by welding, but rather sealed together using the polypropylene layers 11 of each of the two housings 1, thus avoiding the problems of weld explosions and leaks caused by welding steel housings. Furthermore, the polypropylene layers 11 of each of the two housings 1 effectively prevent moisture and air from entering the assembly space, protecting the battery cell 2. Simultaneously, this application utilizes a cover structure, combined with the sealing of the polypropylene layers 11, to provide good physical protection for the battery cell 2, reducing the impact of external damage on the battery cell 2. More importantly, the assembly space formed by this cover structure can more flexibly accommodate the battery cell 2, optimizing the spatial layout and improving the battery's energy density. Moreover, the cover structure is relatively simple, easy to assemble and produce, reducing manufacturing difficulty and cost.

[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 two housings (1) that are covered together and a battery cell (2) disposed between the two housings (1); Each of the housings (1) comprises a polypropylene layer (11) and a steel layer (12), and the two housings (1) are sealed together by their respective polypropylene layers (11).

2. The battery according to claim 1, characterized in that, The connection structure of the polypropylene layers (11) of the two shells (1) can be specifically achieved by thermo-press sealing or adhesive sealing.

3. A battery according to claim 1 or 2, characterized in that, The two housings (1) are vertically fitted together, one of the housings (1) includes an inner polypropylene layer (11) and an outer steel layer (12), and the other housing (1) includes an inner steel layer (12) and an outer polypropylene layer (11). The inner side of the inner polypropylene layer (11) of one of the housings (1) is sealed to the outer side of the outer polypropylene layer (11) of the other housing (1).

4. A battery according to claim 1 or 2, characterized in that, The two shells (1) are square half-shells, and the length and width of one of the shells (1) are greater than the length and width of the other shell (1); Alternatively, the two shells (1) are cylindrical half-shells, with the diameter of one shell (1) being larger than the diameter of the other shell (1).

5. A battery according to claim 1 or 2, characterized in that, When the two housings (1) are closed, the steel layer (12) of each of the two housings (1) is used for magnetic conduction, and the polypropylene layer (11) of each of the two housings (1) is heat-sealed.

6. A battery according to claim 1 or 2, characterized in that, The battery cell (2) has a positive electrode tab (21) and a negative electrode tab (22), and the positive electrode tab (21) and the negative electrode tab (22) are welded to the steel layers (12) of the two shells (1) respectively.

7. A battery according to claim 6, characterized in that, One of the positive electrode tabs (21) and the negative electrode tab (22) is welded to the inner top wall of the steel layer (12) of the shell (1) of one of them, and the other is welded to the inner bottom wall of the steel layer (12) of the shell (1) of the other.

8. A battery according to claim 1 or 2, characterized in that, The two housings (1) are stamped.

9. A battery according to claim 1 or 2, characterized in that, The two housings (1) are designed without injection holes.

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

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