Single battery

Abstract

The utility model relates to the technical field of batteries, and discloses a single battery. The single battery can comprise a battery shell and a cover plate, the battery shell comprises a first metal shell and a second metal shell, the first metal shell and the second metal shell are stacked and fixedly connected, the material of the first metal shell is different from that of the second metal shell, the battery shell is provided with an opening part, and the first metal shell protrudes out of the second metal shell at the opening part; the size of the part, protruding out of the second metal shell, of the first metal shell is larger than or equal to 0.1 mm and smaller than or equal to 5 mm; the cover plate covers the opening part, the material of at least part of the cover plate is the same as that of the first metal shell, and the cover plate is connected with the first metal shell in a welded mode. According to the single battery, an intact welding connection part can be formed between the first metal shell and the cover plate, so that the welding effect between the first metal shell and the cover plate is ensured; and enough strength of the battery shell is ensured.

Description

Technical Field

[0001] The present disclosure relates to the technical field of batteries, and in particular to a single battery. Background Art

[0002] When the battery case is made of a single metal material, it is difficult to meet all the performance requirements of a single cell, and the cost of modifying the metal to meet all the performance requirements of a single cell is high; therefore, the battery case is set to a two-layer metal structure, but the two-layer metal structure of the battery case and the cover plate is difficult to weld.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Utility Model Content

[0004] The purpose of the present disclosure is to overcome the deficiencies of the above-mentioned related technologies and provide a single cell.

[0005] According to one aspect of the present disclosure, there is provided a single cell battery, comprising:

[0006] A battery case, comprising a first metal case and a second metal case, wherein the first metal case and the second metal case are stacked and fixedly connected, the material of the first metal case is different from the material of the second metal case, the battery case has an opening, the first metal case protrudes from the second metal case at the opening, so that the end surface of the opening is set as a step surface, and the dimension of the first metal case protruding from the second metal case is greater than or equal to 0.1 mm and less than or equal to 5 mm;

[0007] A cover plate is disposed on the opening, wherein at least a portion of the cover plate is made of the same material as the first metal shell, and the cover plate is connected to the first metal shell by welding.

[0008] The single cell battery disclosed in the present invention, on the one hand, by setting the first metal shell in the opening portion to protrude from the second metal shell, when the cover plate and the first metal shell are welded, only the portion where the cover plate and the first metal shell need to be connected needs to be melted, and the second metal shell will not be melted, so that a complete welding connection portion can be formed between the first metal shell and the cover plate, thereby ensuring the welding effect between the first metal shell and the cover plate, and further ensuring the connection strength between the first metal shell and the cover plate, and preventing a safety accident due to leakage of the battery shell; on the other hand, the dimension of the first metal shell protruding from the second metal shell is greater than or equal to 0.1 mm and less than or equal to 5 mm, which not only ensures that the battery shell has sufficient strength and the first metal shell will not be broken at the step, but also ensures that the welding of the first metal shell and the cover plate will not be affected.

[0009] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0011] Figure 1 It is a schematic structural diagram of a first exemplary embodiment of a single cell disclosed in the present invention.

[0012] Figure 2 It is a schematic structural diagram of a second exemplary embodiment of a single cell disclosed in the present invention.

[0013] Figure 3 It is a schematic structural diagram of a third exemplary embodiment of a single cell disclosed in the present invention.

[0014] Description of reference numerals:

[0015] 1. Battery housing; 11. First metal housing; 12. Second metal housing; 13. Opening; 14. Bottom wall plate; 15. Side plate;

[0016] 2. Cover plate; 3. Battery cell. DETAILED DESCRIPTION

[0017] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0018] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.

[0019] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0020] In this application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. "And / or" is just a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the previous and next associated objects are in an "or" relationship.

[0021] The exemplary embodiment of the present disclosure provides a single battery, referring to Figure 1-Figure 3 As shown, the single battery may include a battery shell 1 and a cover plate 2; the battery shell 1 may include a first metal shell 11 and a second metal shell 12, the first metal shell 11 and the second metal shell 12 are stacked and fixedly connected, the material of the first metal shell 11 is different from the material of the second metal shell 12, the battery shell 1 has an opening 13, the first metal shell 11 protrudes from the second metal shell 12 at the opening 13, so that the end surface of the opening 13 is set as a step surface, and the dimension of the first metal shell 11 protruding from the second metal shell 12 is greater than or equal to 0.1 mm and less than or equal to 5 mm; the cover plate 2 is covered on the opening 13, at least part of the material of the cover plate 2 is the same as the material of the first metal shell 11, and the cover plate 2 is welded to the first metal shell 11.

[0022] The single cell battery disclosed in the present invention, on the one hand, is configured such that the first metal shell 11 is protruding from the second metal shell 12 at the opening 13, so that when the cover plate 2 and the first metal shell 11 are welded, only the portion where the cover plate 2 and the first metal shell 11 need to be connected is melted, and the second metal shell 12 will not be melted, so that a complete welding connection portion can be formed between the first metal shell 11 and the cover plate 2, thereby ensuring the welding effect between the first metal shell 11 and the cover plate 2, and further ensuring the connection strength between the first metal shell 11 and the cover plate 2, and preventing a safety accident from being caused by leakage of the battery shell 1; on the other hand, the dimension of the first metal shell 11 protruding from the second metal shell 12 is greater than or equal to 0.1 mm and less than or equal to 5 mm, which not only ensures that the battery shell 1 is strong enough and the first metal shell 11 will not be broken at the step, but also ensures that the welding of the first metal shell 11 and the cover plate 2 will not be affected.

[0023] In this example embodiment, the single battery may be a quadrangular prism battery. Figure 1-Figure 3 As shown, the battery housing 1 of the quadrangular prism battery can be set to a rectangular parallelepiped structure. Specifically, the battery housing 1 may include five wall panels, which are a bottom wall panel 14 and four side panels 15. The four side panels 15 are arranged opposite to each other in pairs; the four side panels 15 are connected end to end in sequence to form a rectangular cylindrical shape. The bottom wall panel 14 is connected to one side of the four side panels 15, so that the bottom wall panel 14 and the four side panels 15 are surrounded to form a accommodating cavity. The cover plate 2 is connected to the other side of the four side panels 15, and the opening 13 of the battery housing 1 is sealed by the cover plate 2.

[0024] Of course, in some other example embodiments of the present disclosure, the bottom wall plate 14 and the cover plate 2 can be set to be circular, elliptical, trapezoidal, etc., and the side plate 15 can be set to one or more, and surround to form a circular, elliptical, trapezoidal, etc. shape, so that the battery housing 1 is formed into a cylindrical, elliptical column, prismatic, etc.

[0025] A battery cell 3 is arranged in the battery housing 1 .

[0026] In this example implementation, refer to Figure 1-Figure 3 As shown, the battery housing 1 may include a first metal housing 11 and a second metal housing 12 which are stacked, so that the bottom wall plate 14 and four side plates 15 of the battery housing 1 are both two-layer stacked structures including a first metal layer and a second metal layer.

[0027] In this example embodiment, the first metal shell 11 is fixedly connected to the second metal shell 12. For example, the first metal shell 11 and the second metal shell 12 can be an integrally formed structure, that is, the first metal shell 11 and the second metal shell 12 can be formed by an integrally formed process. For example, a second metal layer can be formed on the first metal layer, and then the first metal layer and the second metal layer are simultaneously subjected to a stamping process or a stretching process, so that the first metal layer and the second metal layer form a battery shell 1 with a receiving cavity, that is, the first metal layer forms the first metal shell 11, and the second metal layer forms the second metal shell 12. The integrally formed structure is not to firstly perform a stamping process or a stretching process on the first metal layer to form a first metal shell 11 with a receiving cavity, and then form the second metal shell 12 on the first metal shell 11. The integrally formed structure makes the connection between the first metal shell 11 and the second metal shell 12 tighter, and there is almost no gap between the first metal shell 11 and the second metal shell 12. Moreover, the preparation process is relatively simple, which is conducive to improving production efficiency.

[0028] Of course, in some other example embodiments of the present disclosure, the first metal shell 11 and the second metal shell 12 may not be an integrally formed structure, that is, the first metal layer may first be subjected to a stamping process or a stretching process to form a first metal shell 11 with a accommodating cavity, and then the second metal shell 12 may be formed on the first metal shell 11.

[0029] In this exemplary embodiment, the material of the first metal shell 11 is different from the material of the second metal shell 12. One of the first metal shell 11 and the second metal shell 12 is made of copper or steel, and the other is made of aluminum or aluminum alloy. Figure 2 As shown, when the second metal shell 12 is arranged on the outer surface of the first metal shell 11, that is, when the second metal shell 12 is the outer shell of the battery shell 1, and the first metal shell 11 is the inner shell of the battery shell 1, the material of the first metal shell 11 is copper or steel, and the material of the second metal shell 12 is aluminum or aluminum alloy, that is, the inner layer material of the battery shell 1 is copper or steel, and the outer layer material is aluminum or aluminum alloy.

[0030] Of course, in some other exemplary embodiments of the present disclosure, reference Figure 1 and Figure 3 As shown, when the first metal shell 11 is arranged on the outer surface of the second metal shell 12, that is, when the first metal shell 11 is the outer shell of the battery shell 1, and the second metal shell 12 is the inner shell of the battery shell 1, the material of the second metal shell 12 is copper or steel, and the material of the first metal shell 11 is aluminum or aluminum alloy, that is, the inner layer material of the battery shell 1 is copper or steel, and the outer layer material is aluminum or aluminum alloy.

[0031] Generally, the negative electrode sheet of the battery cell 3 exceeds the positive electrode sheet of the battery cell 3, and the negative electrode sheet of the battery cell 3 is arranged on the outside; the potential of the negative electrode sheet is relatively low, and the corrosion potential of aluminum or aluminum alloy is relatively low. If aluminum or aluminum alloy is used as the inner layer material of the battery shell 1, aluminum or aluminum alloy is easy to overlap with the negative electrode sheet to form lithium aluminum alloy, and the texture of lithium aluminum alloy is relatively brittle, thereby reducing the strength of the battery shell 1; copper has a lower corrosion risk, and steel has a higher corrosion potential. Even if it overlaps with the low-potential negative electrode sheet, it is difficult to be corroded by electricity. Therefore, setting the inner layer material of the battery shell 1 to copper or steel can reduce or even avoid electrical corrosion of the battery shell 1 to ensure the strength of the battery shell 1.

[0032] In addition, according to the different performances that the battery housing 1 needs to meet, the material of the first metal housing 11 and the material of the second metal housing 12 may also be set to other materials, which are not described here one by one.

[0033] In this example implementation, refer to Figure 1-Figure 3 As shown, the battery housing 1 has an opening 13, where the first metal housing 11 protrudes from the second metal housing 12, so that the end surface of the opening 13 is set as a stepped surface, that is, the end surface of the opening 13 is not a flat plane.

[0034] The cover plate 2 covers the opening 13 . The material of the cover plate 2 is the same as that of the first metal shell 11 . The cover plate 2 is connected to the first metal shell 11 by welding.

[0035] Since the material of the first metal shell 11 is different from that of the second metal shell 12, the melting point of the first metal shell 11 is different from that of the second metal shell 12. If the first metal shell 11 and the second metal shell 12 are set to be flush structures at the opening 13, when the cover plate 2 and the first metal shell 11 are welded, a part of the opening 13 of the second metal shell 12 will be melted, resulting in an uneven surface of the second metal shell 12; and since the heat generated by welding is limited, a part of the first metal shell 11 cannot be melted well, resulting in a failure to form a complete welding connection between the first metal shell 11 and the cover plate 2, affecting the welding effect between the first metal shell 11 and the cover plate 2, reducing the connection strength between the first metal shell 11 and the cover plate 2, and even worse, causing the battery shell 1 to leak and cause a safety accident. Of course, when the cover plate 2 is welded to the second metal shell 12, there may be a technical problem that a complete welding connection cannot be formed; when the cover plate 2 is welded to both the first metal shell 11 and the second metal shell 12, there is no suitable welding temperature, and there may also be a technical problem that a complete welding connection cannot be formed.

[0036] By setting the first metal shell 11 in the opening portion 13 to protrude from the second metal shell 12, when the cover plate 2 and the first metal shell 11 are welded, only the portion that needs to be connected between the cover plate 2 and the first metal shell 11 is melted, and the second metal shell 12 will not be melted, so that a complete welding connection can be formed between the first metal shell 11 and the cover plate 2, thereby ensuring the welding effect between the first metal shell 11 and the cover plate 2, and further ensuring the connection strength between the first metal shell 11 and the cover plate 2, and preventing a safety accident caused by leakage of the battery shell 1.

[0037] Moreover, refer to Figure 1 and Figure 2 As shown, the dimension H1 of the first metal shell 11 protruding from the second metal shell 12 is greater than or equal to 0.1 mm and less than or equal to 5 mm. For example, the dimension H1 of the first metal shell 11 protruding from the second metal shell 12 can be 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.7 mm, 2 mm, 2.3 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.7 mm, 4 mm, 4.3 mm, 4.5 mm, 4.8 mm, etc.

[0038] If the dimension H1 of the first metal shell 11 protruding from the second metal shell 12 is too large, the battery shell 1 will be provided with only one layer of the first metal shell 11, and the single-layer structure will be too large, resulting in relatively weak strength of the battery shell 1, especially at the step, the risk of the first metal shell 11 breaking is greater.

[0039] If the dimension H1 of the first metal shell 11 protruding from the second metal shell 12 is too small, the second metal shell 12 will still affect the welding between the first metal shell 11 and the cover plate 2 .

[0040] The above numerical range not only ensures that the battery housing 1 is strong enough and the first metal housing 11 will not break at the step, but also ensures that the welding between the first metal housing 11 and the cover plate 2 will not be affected.

[0041] The elastic modulus can be regarded as an indicator of the ease with which a material can produce elastic deformation. The larger its value, the greater the stress that causes a certain elastic deformation of the material, that is, the greater the material stiffness, that is, the smaller the elastic deformation under a certain stress. In this example embodiment, the elastic modulus of the first metal shell 11 is greater than the elastic modulus of the second metal shell 12, that is, the stiffness of the first metal shell 11 is greater than the stiffness of the second metal shell 12.

[0042] Moreover, the wall thickness of the first metal shell 11 is smaller than the wall thickness of the second metal shell 12. Specifically, the wall thickness of the first metal shell 11 is greater than or equal to 0.05 mm and less than or equal to 0.3 mm. For example, the wall thickness of the first metal shell 11 can be 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.28 mm, etc.

[0043] Of course, in some other exemplary embodiments of the present disclosure, the elastic modulus of the second metal shell 12 may be greater than the elastic modulus of the first metal shell 11, that is, the rigidity of the second metal shell 12 is greater than the rigidity of the first metal shell 11. Moreover, the wall thickness of the second metal shell 12 is less than the wall thickness of the first metal shell 11. Specifically, the wall thickness of the second metal shell 12 is greater than or equal to 0.05 mm and less than or equal to 0.3 mm. For example, the wall thickness of the second metal shell 12 may be 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.28 mm, and the like.

[0044] That is, setting the wall thickness of the shell with greater rigidity to be smaller can not only ensure the overall strength of the battery shell 1, but also increase the internal space of the battery shell 1, that is, increase the volume of the battery shell 1, which is beneficial to improve the energy density of the single battery.

[0045] In this example embodiment, the thermal conductivity of the first metal shell 11 is greater than the thermal conductivity of the second metal shell 12, and the ratio of the wall thickness of the first metal shell 11 to the wall thickness of the second metal shell 12 is greater than or equal to 1.2. For example, the ratio of the wall thickness of the first metal shell 11 to the wall thickness of the second metal shell 12 can be 1.5, 1.7, 2, 2.3, 2.5, 2.7, 3, 3.3, 3.5, 3.7, 4, etc. Setting the wall thickness of the first metal shell 11 with a larger thermal conductivity to be thicker can improve the overall thermal conductivity of the battery shell 1. Moreover, if the ratio of the wall thickness of the first metal shell 11 to the wall thickness of the second metal shell 12 is too small, the effect of increasing the overall thermal conductivity of the battery shell 1 is not significant.

[0046] Of course, in some other exemplary embodiments of the present disclosure, the thermal conductivity of the second metal shell 12 may be greater than the thermal conductivity of the first metal shell 11, and the ratio of the wall thickness of the second metal shell 12 to the wall thickness of the first metal shell 11 may be greater than or equal to 1.2. For example, the ratio of the wall thickness of the second metal shell 12 to the wall thickness of the first metal shell 11 may be 1.5, 1.7, 2, 2.3, 2.5, 2.7, 3, 3.3, 3.5, 3.7, 4, etc. Similarly, setting the wall thickness of the second metal shell 12 with a larger thermal conductivity to be thicker can improve the thermal conductivity of the battery shell 1 as a whole. Moreover, if the ratio of the wall thickness of the second metal shell 12 to the wall thickness of the first metal shell 11 is too small, the effect of increasing the thermal conductivity of the battery shell 1 as a whole is not significant.

[0047] In this example implementation, refer to Figure 1 and Figure 3 As shown, the first metal shell 11 can be arranged on the outer surface of the second metal shell 12, that is, the first metal shell 11 is the outer shell of the battery shell 1, and the second metal shell 12 is the inner shell of the battery shell 1; and because the first metal shell 11 protrudes from the second metal shell 12 at the opening 13, a step structure in which the outer shell protrudes from the inner shell is formed at the opening 13.

[0048] Reference Figure 1 As shown, the cover plate 2 can be mounted on the end face of the second metal shell 12 at the opening 13. Specifically, the edge of the cover plate 2 is mounted on the end face of the second metal shell 12, so that the second metal shell 12 can limit the cover plate 2. There is no need to set a limiting structure inside the battery shell 1 or on the cover plate 2 separately, and the strength of the battery shell 1 or the cover plate 2 will not be reduced due to the setting of the limiting structure. Therefore, limiting the cover plate 2 by the second metal shell 12 not only simplifies the preparation process of the battery shell 1 or the cover plate 2, but also does not affect the strength of the battery shell 1 or the cover plate 2. In this case, the cover plate 2 is welded to the inner surface of the first metal shell 11. For example, the cover plate 2 can be welded to the first metal shell 11 from the side of the cover plate 2 away from the second metal shell 12. The welding heat needs to pass through the cover plate 2 to reach the second metal shell 12. Therefore, it has a certain protective effect on the second metal shell 12.

[0049] The thickness of the cover plate 2 may be equal to the dimension H1 of the first metal shell 11 protruding from the second metal shell 12. Of course, the thickness of the cover plate 2 may also be slightly greater than or less than the dimension H1 of the first metal shell 11 protruding from the second metal shell 12.

[0050] It should be noted that the cover plate 2 is only mounted on the end surface of the second metal shell 12 , but is not connected to the second metal shell 12 .

[0051] Reference Figure 3As shown, the cover plate 2 can also be welded to the end surface of the first metal shell 11 at the opening 13. The cover plate 2 can be limited by the first metal shell 11. In this case, the outer peripheral surface of the cover plate 2 is substantially coplanar with the outer surface of the first metal shell 11, and the cover plate 2 and the first metal shell 11 can be welded from the outer peripheral surface of the cover plate 2 and the outer surface of the first metal shell 11.

[0052] In some example embodiments of the present disclosure, reference is made to Figure 2 As shown, the second metal shell 12 can be arranged on the outer surface of the first metal shell 11, that is, the second metal shell 12 is the outer shell of the battery shell 1, and the first metal shell 11 is the inner shell of the battery shell 1; and because the first metal shell 11 protrudes from the second metal shell 12 at the opening 13, a step structure is formed in which the inner shell protrudes from the outer shell at the opening 13. In this case, the cover plate 2 can also be welded to the end face of the first metal shell 11 at the opening 13. The outer peripheral surface of the cover plate 2 is substantially coplanar with the outer surface of the first metal shell 11, and the cover plate 2 and the first metal shell 11 can be welded from the outer peripheral surface of the cover plate 2 and the outer surface side of the first metal shell 11. The first metal shell 11 can limit the cover plate 2, and there is no need to set a limiting structure inside the battery shell 1 or on the cover plate 2 separately, and the strength of the battery shell 1 or the cover plate 2 will not be reduced due to the setting of the limiting structure. Therefore, limiting the cover plate 2 by the first metal shell 11 not only simplifies the preparation process of the battery shell 1 or the cover plate 2 , but also does not affect the strength of the battery shell 1 or the cover plate 2 .

[0053] Moreover, the dimension H1 of the first metal shell 11 protruding from the second metal shell 12 is greater than or equal to 0.1mm and less than or equal to 4.5mm. For example, the dimension H1 of the first metal shell 11 protruding from the second metal shell 12 can be 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.7mm, 2mm, 2.3mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.7mm, 4mm, 4.3mm, etc.

[0054] If the dimension H1 of the first metal shell 11 protruding from the second metal shell 12 is too large, resulting in a larger dimension of the step structure formed on the outside of the battery shell 1, the insulating film on the outside of the battery shell 1 is difficult to fit well with the battery shell 1 at the step structure; moreover, after the single cells are grouped, two adjacent single cells cannot contact each other at the step structure and a gap is formed, resulting in a slow heat transfer rate between the two adjacent single cells, affecting the heat dissipation effect of the entire battery pack.

[0055] In this exemplary embodiment, the melting point of the first metal shell 11 may be greater than the melting point of the second metal shell 12. Specifically, the difference between the melting point of the first metal shell 11 and the melting point of the second metal shell 12 is less than or equal to 900°C. For example, the difference between the melting point of the first metal shell 11 and the melting point of the second metal shell 12 may be 500°C, 520°C, 550°C, 570°C, 600°C, 630°C, 650°C, 680°C, 700°C, 720°C, 750°C, 770°C, 800°C, 830°C, 850°C, 880°C, etc. This arrangement avoids the excessively high melting point of the first metal shell 11, which may result in excessively high power required for welding the first metal shell 11, thereby causing the risk of cold welding of the cover plate 2; and avoids the risk of melting the second metal shell 12 due to excessively high temperature during welding, thereby causing poor surface flatness of the battery shell 1.

[0056] In some other exemplary embodiments of the present disclosure, the melting point of the first metal shell 11 may be lower than the melting point of the second metal shell 12. Specifically, the difference between the melting point of the second metal shell 12 and the melting point of the first metal shell 11 is greater than 400°C. For example, the difference between the melting point of the second metal shell 12 and the melting point of the first metal shell 11 may be 100°C, 120°C, 150°C, 170°C, 200°C, 230°C, 250°C, 280°C, 300°C, 320°C, 350°C, 370°C, etc. In this way, the melting point of the first metal shell 11 is prevented from being close to the melting point of the second metal shell 12. When the first metal shell 11 and the cover plate 2 are welded, the second metal shell 12 melts, resulting in poor surface flatness of the battery shell 1.

[0057] The material of at least part of the cover plate 2 is the same as the material of the first metal shell 11. For example, the material of the entire cover plate 2 may be the same as the material of the first metal shell 11. In this case, the cover plate 2 may be set to a single-layer structure. The material of the part of the cover plate 2 close to the first metal shell 11 may be the same as the material of the first metal shell 11, while the material of other parts is different from the material of the first metal shell 11. The cover plate 2 may be set to a two-layer or multi-layer structure.

[0058] In this exemplary embodiment, the thickness of the cover plate 2 is greater than the wall thickness of the first metal shell 11 , and the thickness of the cover plate 2 is greater than the wall thickness of the second metal shell 12 . Such an arrangement can ensure the strength of the cover plate 2 .

[0059] Of course, in some other exemplary embodiments of the present disclosure, the thickness of the cover plate 2 may be only greater than the wall thickness of the first metal shell 11 ; or the thickness of the cover plate 2 may be only greater than the wall thickness of the second metal shell 12 .

[0060] The "parallel" and "perpendicular" mentioned in this application can not only be completely parallel or perpendicular, but also can have a certain error; for example, if the angle between the two is greater than or equal to 0° and less than or equal to 5°, the two are considered to be parallel to each other; if the angle between the two is greater than or equal to 85° and less than or equal to 95°, the two are considered to be perpendicular to each other.

[0061] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the utility model disclosed herein. This application is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A single cell battery, characterized in that: include: A battery case, comprising a first metal case and a second metal case, wherein the first metal case and the second metal case are stacked and fixedly connected, the material of the first metal case is different from the material of the second metal case, the battery case has an opening, the first metal case protrudes from the second metal case at the opening, so that the end surface of the opening is set as a step surface, and the dimension of the first metal case protruding from the second metal case is greater than or equal to 0.1 mm and less than or equal to 5 mm; A cover plate is disposed on the opening, wherein at least a portion of the cover plate is made of the same material as the first metal shell, and the cover plate is connected to the first metal shell by welding.

2. The single cell according to claim 1, characterized in that: The elastic modulus of the first metal shell is greater than the elastic modulus of the second metal shell, and the wall thickness of the first metal shell is less than the wall thickness of the second metal shell; or, the elastic modulus of the second metal shell is greater than the elastic modulus of the first metal shell, and the wall thickness of the second metal shell is less than the wall thickness of the first metal shell.

3. The single cell according to claim 2, characterized in that: When the elastic modulus of the first metal shell is greater than the elastic modulus of the second metal shell, the wall thickness of the first metal shell is greater than or equal to 0.05 mm and less than or equal to 0.3 mm; or, when the elastic modulus of the second metal shell is greater than the elastic modulus of the first metal shell, the wall thickness of the second metal shell is greater than or equal to 0.05 mm and less than or equal to 0.3 mm.

4. The single cell according to claim 1, characterized in that: The thermal conductivity of the first metal shell is greater than the thermal conductivity of the second metal shell, and the ratio of the wall thickness of the first metal shell to the wall thickness of the second metal shell is greater than or equal to 1.2; or, the thermal conductivity of the second metal shell is greater than the thermal conductivity of the first metal shell, and the ratio of the wall thickness of the second metal shell to the wall thickness of the first metal shell is greater than or equal to 1.

2.

5. The single cell according to any one of claims 1 to 4, characterized in that: The first metal shell is arranged on the outer surface of the second metal shell, the cover plate is mounted on the end surface of the second metal shell at the opening, and the cover plate is welded to the inner surface of the first metal shell; or, the cover plate is welded to the end surface of the first metal shell at the opening.

6. The single cell according to any one of claims 1 to 4, characterized in that: The second metal shell is disposed on the outer surface of the first metal shell, the cover plate is welded to the end surface of the first metal shell at the opening, and the dimension of the first metal shell protruding from the second metal shell is greater than or equal to 0.1 mm and less than or equal to 4.5 mm.

7. The single cell according to any one of claims 1 to 4, characterized in that: The melting point of the first metal shell is greater than that of the second metal shell, and the difference between the melting points of the first metal shell and the second metal shell is less than or equal to 900°C; or, the melting point of the first metal shell is less than that of the second metal shell, and the difference between the melting points of the second metal shell and the first metal shell is greater than 400°C.

8. The single cell according to any one of claims 1 to 4, characterized in that: The second metal shell is arranged on the outer surface of the first metal shell, the material of the first metal shell is copper or steel, and the material of the second metal shell is aluminum or aluminum alloy; or, the first metal shell is arranged on the outer surface of the second metal shell, the material of the second metal shell is copper or steel, and the material of the first metal shell is aluminum or aluminum alloy.

9. The single cell according to any one of claims 1 to 4, characterized in that: The thickness of the cover plate is greater than the wall thickness of the first metal shell, and / or the thickness of the cover plate is greater than the wall thickness of the second metal shell.

10. The single cell according to any one of claims 1 to 4, characterized in that: The first metal shell and the second metal shell are an integrally formed structure.

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