Battery cell

Abstract

The utility model relates to the technical field of batteries, and discloses a battery monomer. The battery monomer comprises a composite shell, a cover plate and a binding connection structure, the composite shell comprises a shell metal layer and a shell insulating layer which are arranged in a stacked mode, the shell metal layer and the shell insulating layer are of an integrally-formed structure, the composite shell is provided with an opening part, the opening part is of a two-layer structure comprising the shell metal layer and the shell insulating layer, and the tensile strength of the shell metal layer is larger than or equal to 120 MPa and smaller than or equal to 200 MPa; the cover plate covers the opening part and is provided with an edge part; the binding connection structure is arranged on the edge part and the opening part. According to the single battery, the defects of hole explosion and the like caused by adopting a welding connection structure are avoided, so that the connection strength and the sealing effect between the cover plate and the composite shell are ensured.

Description

Technical Field

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

[0002] The existing composite shell includes a stacked shell metal layer and a shell insulation layer. However, since the melting point of the shell insulation layer is much lower than that of the shell metal layer, defects such as blowout holes are easily generated when the composite shell and the cover plate are welded, resulting in difficulty in welding the composite shell and the cover plate. Even if the composite shell and the cover plate are barely welded together, the welding connection is prone to sealing failure.

[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 battery cell.

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

[0006] A composite shell, comprising a shell metal layer and a shell insulating layer stacked together, the shell metal layer and the shell insulating layer being an integrally formed structure, the composite shell having an opening, the opening being a two-layer structure comprising the shell metal layer and the shell insulating layer, the tensile strength of the shell metal layer being greater than or equal to 120 MPa and less than or equal to 200 MPa;

[0007] A cover plate, covering the opening, and having an edge portion;

[0008] The rolled edge connection structure is arranged at the edge portion and the opening portion.

[0009] The battery cell disclosed in the present invention, on the one hand, connects the cover plate and the composite shell as a whole through a rolling connection structure, and makes the cover plate and the composite shell sealed, avoiding defects such as explosion holes caused by the use of a welding connection structure, so as to ensure the connection strength and sealing effect between the cover plate and the composite shell; on the other hand, the tensile strength of the metal layer of the shell is greater than or equal to 120MPa and less than or equal to 200Mpa, which not only ensures that the metal layer of the shell can be deformed to achieve the rolling connection structure connection between the composite shell and the cover plate, and ensures the sealing effect between the composite shell and the cover plate, but also ensures that the strength of the metal layer of the shell can support and protect the battery cell, and can effectively support the shell insulating layer, avoiding deformation and damage of the shell insulating layer, so as to ensure the insulating effect of the shell insulating layer.

[0010] 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

[0011] 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.

[0012] Figure 1 It is a schematic diagram of the three-dimensional structure of an exemplary embodiment of a battery cell disclosed in the present invention.

[0013] Figure 2 FIG. 1 is a cross-sectional schematic diagram of a first exemplary embodiment of a battery cell disclosed herein.

[0014] Figure 3 It is a cross-sectional schematic diagram of a second exemplary embodiment of a battery cell disclosed herein.

[0015] Figure 4 FIG. 1 is a schematic cross-sectional view of a third exemplary embodiment of a battery cell according to the present disclosure.

[0016] Figure 5 Schematic cross-sectional view of a fourth exemplary embodiment of a battery cell according to the present disclosure.

[0017] Description of reference numerals:

[0018] 1. Composite shell; 11. Shell metal layer; 12. Shell insulation layer; 13. Opening; 14. Limiting structure;

[0019] 2. Cover plate; 21. Edge;

[0020] 3. Rolling connection structure; 31. Shell flange portion; 311. Metal layer flange portion; 312. Insulation layer flange portion; 32. Cover plate flange portion;

[0021] 4. Seals;

[0022] 5. battery cell; 51. main body; 52. positive electrode ear; 53. negative electrode ear;

[0023] 6. Battery terminal. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The exemplary embodiment of the present disclosure provides a battery cell, referring to Figure 1-Figure 5As shown, the battery cell may include a composite shell 1, a cover plate 2 and a rolled edge connection structure 3; the composite shell 1 may include a stacked shell metal layer 11 and a shell insulating layer 12, the shell metal layer 11 and the shell insulating layer 12 are an integrally formed structure, the composite shell 1 has an opening portion 13, the opening portion 13 is arranged to be a two-layer structure including the shell metal layer 11 and the shell insulating layer 12, the tensile strength of the shell metal layer 11 is greater than or equal to 120MPa and less than or equal to 200MPa; the cover plate 2 covers the opening portion 13, and the cover plate 2 has an edge portion 21; the rolled edge connection structure 3 is arranged at the edge portion 21 and the opening portion 13.

[0029] The battery cell disclosed in the present invention, on the one hand, connects the cover plate 2 and the composite shell 1 as a whole through the rolling connection structure 3, and makes the cover plate 2 and the composite shell 1 sealed, avoiding defects such as explosion holes caused by the use of welding connection structure, so as to ensure the connection strength and sealing effect between the cover plate 2 and the composite shell 1; on the other hand, the tensile strength of the shell metal layer 11 is greater than or equal to 120MPa and less than or equal to 200Mpa, which not only ensures that the shell metal layer 11 can be deformed to realize the connection of the composite shell 1 and the cover plate 2 with the rolling connection structure 3, but also ensures the sealing effect between the composite shell 1 and the cover plate 2; and also ensures that the strength of the shell metal layer 11 can support and protect the battery cell 5, and can effectively support the shell insulating layer 12, avoiding deformation and damage of the shell insulating layer 12, so as to ensure the insulating effect of the shell insulating layer 12.

[0030] In this example implementation, refer to Figure 1-Figure 5 As shown, the battery cell can be a cylindrical battery, so the composite shell 1 can be set as a cylinder, that is, the composite shell 1 can include a bottom wall plate and a side plate, the bottom wall plate is set to be circular, and the side plate is set to be cylindrical. The bottom wall plate is connected to one end of the side plate, so that the other end of the composite shell 1 forms an opening 13, that is, the composite shell 1 has an opening 13. The bottom wall plate and the side plate surround the accommodating cavity of the battery cell. A cover plate 2 is connected to the other side of the side plate, that is, the cover plate 2 covers the opening 13, and the cover 2 is used to seal the opening 13 of the composite shell 1.

[0031] Of course, in some other example embodiments of the present disclosure, the battery cell may also be a quadrangular prism battery, an elliptical prism battery or other prismatic battery, the bottom wall plate and the cover plate 2 may be set to be rectangular, elliptical, other polygonal, etc., the side plate may be set to be one or more, and surrounded by a rectangular, elliptical, other polygonal cylinder, etc., so that the composite shell 1 is formed into a quadrangular prism, an elliptical prism or other prism, etc.

[0032] In this example embodiment, the composite housing 1 may include a housing metal layer 11 and a housing insulation layer 12 which are stacked, so that the bottom wall plate and the side plate of the composite housing 1 are both a stacked structure including two layers of a metal layer and an insulation layer.

[0033] The shell metal layer 11 and the shell insulating layer 12 can be an integrally formed structure, that is, the shell metal layer 11 and the shell insulating layer 12 can be formed by an integrally formed process. For example, an insulating layer can be formed on a metal plate by bonding, coating, hot melting and other processes, and then the metal plate formed with the insulating layer is subjected to a stamping process or a stretching process, so that the metal plate formed with the insulating layer forms a composite shell 1 with a accommodating cavity, that is, the metal plate forms the shell metal layer 11, and the insulating layer forms the shell insulating layer 12. The integrally formed structure does not first form the shell metal layer 11 with a accommodating cavity by a stamping process or a stretching process on the metal plate, and then form the shell insulating layer 12 on the shell metal layer 11 by bonding, coating, hot melting and other processes. The integrally formed structure makes the connection between the shell metal layer 11 and the shell insulating layer 12 tighter, and there is almost no gap between the shell metal layer 11 and the shell insulating layer 12. Moreover, the preparation process is relatively simple, which is conducive to improving efficiency.

[0034] The shell metal layer 11 may be an aluminum shell or an aluminum alloy shell, that is, the shell metal layer 11 may be made of aluminum or an aluminum alloy, etc. Of course, it may also be made of other materials, which will not be described one by one here.

[0035] The material of the shell insulating layer 12 may be a polymer or a resin. For example, the material of the shell insulating layer 12 may be polyethylene, polytetrafluoroethylene, polypropylene, polyimide, polyethylene terephthalate, polycarbonate, and the like.

[0036] The opening 13 is configured as a two-layer structure including a shell metal layer 11 and a shell insulating layer 12, that is, the shell metal layer 11 and the shell insulating layer 12 both extend to the end surface of the opening 13 of the composite shell 1. Generally, the cover plate 2 and the opening 13 of the composite shell 1 are connected as a whole through a welding process. However, since the shell insulating layer 12 may be made of a polymer or a resin, the melting point of the shell insulating layer 12 is much lower than that of the shell metal layer 11. When the composite shell 1 and the cover plate 2 are welded, the shell insulating layer 12 melts and flows first, which is prone to defects such as explosion holes, resulting in difficulty in welding the composite shell 1 and the cover plate 2. Moreover, even if the composite shell 1 and the cover plate 2 are welded together, the welded connection is prone to sealing failure.

[0037] In this example implementation, refer to Figure 2-Figure 5As shown, the cover plate 2 has an edge portion 21, and a circle of the cover plate 2 close to the outermost edge is the edge portion 21, and the edge portion 21 is arranged in a ring shape; the rolling connection structure 3 is arranged at the edge portion 21 and the opening portion 13, that is, the cover plate 2 and the composite shell 1 are connected as a whole through the rolling connection structure 3, and the cover plate 2 and the composite shell 1 are sealed to avoid defects such as explosion holes caused by the use of a welding connection structure, so as to ensure the connection strength and sealing effect between the cover plate 2 and the composite shell 1.

[0038] The tensile strength of the shell metal layer 11 is greater than or equal to 120 MPa and less than or equal to 200 MPa. For example, the tensile strength of the shell metal layer 11 can be 123 MPa, 125 MPa, 128 MPa, 130 MPa, 132 MPa, 135 MPa, 137 MPa, 140 MPa, 143 MPa, 145 MPa, 148 MPa, 150 MPa, 152 MPa, 155 MPa, 157 MPa, 160 MPa, 162 MPa, 165 MPa, 167 MPa, 170 MPa, 173 MPa, 175 MPa, 178 MPa, 180 MPa, 182 MPa, 185 MPa, 187 MPa, 190 MPa, 193 MPa, 195 MPa, 198 MPa and the like.

[0039] Tensile strength is the critical value of the transition of metal from uniform plastic deformation to local concentrated plastic deformation, and is also the maximum load-bearing capacity of metal under static tensile conditions. Tensile strength is the resistance to the maximum uniform plastic deformation of the material. Before the tensile specimen is subjected to the maximum tensile stress, the deformation is uniform, but after exceeding it, the metal begins to shrink, that is, concentrated deformation occurs.

[0040] If the tensile strength of the shell metal layer 11 is too large, the shell metal layer 11 is difficult to deform, and the composite shell 1 and the cover plate 2 are difficult to perform the rolling process. Even if the rolling process is barely achieved, the sealing effect between the composite shell 1 and the cover plate 2 is poor.

[0041] If the tensile strength of the shell metal layer 11 is too small, the shell metal layer 11 is easily deformed, resulting in the composite shell 1 being weak in strength and unable to support and protect the battery cell 5 , and unable to effectively support the shell insulating layer 12 , making the shell insulating layer 12 easily deformed and damaged, which can easily lead to insulation failure of the shell insulating layer 12 .

[0042] The above numerical range not only ensures that the shell metal layer 11 can be deformed to realize the connection between the composite shell 1 and the cover plate 2 by the rolled connection structure 3, but also ensures the sealing effect between the composite shell 1 and the cover plate 2; it also ensures that the strength of the shell metal layer 11 can support and protect the battery cell 5, and can effectively support the shell insulating layer 12 to avoid deformation and damage of the shell insulating layer 12, so as to ensure the insulation effect of the shell insulating layer 12.

[0043] Reference Figure 2 As shown, the roll-up connection structure 3 may include a shell flange portion 31 and a cover plate flange portion 32. The shell flange portion 31 may be formed by bending the opening portion 13 of the composite shell 1 toward the central axis of the battery cell by about 90°, and the cover plate flange portion 32 may be formed by bending the edge portion 21 of the cover plate 2 toward the central axis of the battery cell by about 180°. Moreover, the cover plate flange portion 32 is located on the side of the cover plate 2 away from the battery cell 5, and the shell flange portion 31 is located on the side of the cover plate flange portion 32 away from the battery cell 5. The shell flange portion 31 may include a metal layer flange portion 311 and an insulating layer flange portion 312. When the shell insulating layer 12 is provided on the inner surface of the shell metal layer 11, the metal layer flange portion 311 is located on the side of the insulating layer flange portion 312 away from the battery cell 5.

[0044] Reference Figure 3 and Figure 4 As shown, the roll-up connection structure 3 may only include the shell flange portion 31, but not the cover plate flange portion 32. The shell flange portion 31 may be formed by bending the opening portion 13 of the composite shell 1 toward the central axis of the battery cell by about 90°, and the cover plate flange portion 32 is located on the side of the edge portion 21 of the cover plate 2 away from the battery cell 5. The shell flange portion 31 may include a metal layer flange portion 311 and an insulating layer flange portion 312. When the shell insulating layer 12 is provided on the inner surface of the shell metal layer 11, the insulating layer flange portion 312 is located on the side of the metal layer flange portion 311 away from the battery cell 5; when the shell insulating layer 12 is provided on the inner surface of the shell metal layer 11, the metal layer flange portion 311 is located on the side of the insulating layer flange portion 312 away from the battery cell 5; when the shell insulating layer 12 is provided on the outer surface of the shell metal layer 11, the insulating layer flange portion 312 is located on the side of the metal layer flange portion 311 away from the battery cell 5.

[0045] Reference Figure 5 As shown, the roll-edge connection structure 3 may include a shell flange portion 31 and a cover flange portion 32. The shell flange portion 31 may be formed by bending the opening portion 13 of the composite shell 1 toward the outside of the composite shell 1 and downward by about 180°, and the cover flange portion 32 may be formed by bending the edge portion 21 of the cover plate 2 toward the outside of the composite shell 1 and downward by about 180°, so that the shell flange portion 31 and the cover flange portion 32 are folded on the outside of the composite shell 1, and the cover flange portion 32 is located on the side of the shell flange portion 31 away from the battery cell 5. In the case where the shell insulation layer 12 is provided on the outer surface of the shell metal layer 11, the insulation layer flange portion 312 is located on the side of the metal layer flange portion 311 close to the battery cell 5. Of course, in the case where the shell insulation layer 12 is provided on the inner surface of the shell metal layer 11, the insulation layer flange portion 312 is located on the side of the metal layer flange portion 311 away from the battery cell 5.

[0046] In this case, the outermost part of the edge portion 21 can be first wrapped around the opening portion 13 of the composite shell 1 through a rolling process, and then the opening portion 13 of the composite shell 1 and the edge portion 21 of the cover plate 2 can be rolled again, so that the edge portion 21 of the cover plate 2 forms a winding structure and the opening portion 13 of the composite shell 1 forms a shell flange portion 31, so as to increase the sealing between the composite shell 1 and the cover plate 2.

[0047] In this example implementation, refer to Figure 2-Figure 5 As shown, a battery core 5 is arranged in the receiving cavity of the composite shell 1 , and the battery core 5 is arranged as a cylinder that matches the composite shell 1 .

[0048] The battery cell 5 may include a main body 51, a positive electrode ear 52 and a negative electrode ear 53. The main body 51 may include a first electrode sheet, a separator and a second electrode sheet (not shown in the figure) arranged in layers, that is, the battery cell 5 may include a plurality of first and second electrode sheets arranged in layers, and a separator arranged between the first and second electrode sheets, and the battery cell 5 is a layered type. The battery cell 5 may also be a wound type, and the layered structure formed by the first electrode sheet, the separator and the second electrode sheet is wound to form a wound type battery cell 5. Different active materials are coated on the first and second electrode sheets.

[0049] The polarity of the first electrode is opposite to that of the second electrode. For example, the first electrode may be a positive electrode and the second electrode may be a negative electrode. Of course, the first electrode may be a negative electrode and the second electrode may be a positive electrode.

[0050] The positive electrode tab 52 and the negative electrode tab 53 may be disposed on a side of the first end surface away from the main body 51 , that is, the positive electrode tab 52 and the negative electrode tab 53 are led out from the same side of the main body 51 .

[0051] Specifically, the positive ear 52 is connected to the first pole piece, and the positive ear 52 is located on the side of the first end surface away from the main body 51; a part of the first pole piece may extend out of the main body 51 and be bent to the side of the first end surface away from the main body 51 to form the positive ear 52.

[0052] The negative electrode ear 53 is connected to the second electrode sheet and is located on the side of the first end surface away from the main body 51 . The negative electrode ear 53 may be formed by a portion of the second electrode sheet extending out of the main body 51 and being bent to the side of the first end surface away from the main body 51 .

[0053] Of course, the positive electrode tab 52 and the negative electrode tab 53 may also be disposed on opposite sides of the main body 51 .

[0054] It should be noted that the positive electrode tab 52 and the negative electrode tab 53 are conductive foil areas without active material coating, that is, no active material coating is applied to the positive electrode tab 52 and the negative electrode tab 53 , and they are current collecting layers for transmitting current.

[0055] In this example implementation, refer to Figure 3-Figure 5 As shown, the battery cell may further include a seal 4, which is disposed between the edge portion 21 and the opening portion 13, and the seal 4 may further ensure the sealing effect between the cover plate 2 and the composite shell 1. The seal 4 may be made of rubber, resin, etc., so that the seal 4 is an insulating material.

[0056] Reference Figure 3 and Figure 4 As shown, the seal 4 is arranged in a ring shape surrounding the edge portion 21, and a groove is arranged on the side of the seal 4 close to the edge portion 21, and the edge portion 21 can be embedded in the groove, so that the seal 4 can seal and insulate the outer peripheral surface of the edge portion 21, the side close to the battery cell 5, and the side away from the battery cell 5 from the composite shell 1.

[0057] Reference Figure 5 As shown, the seal 4 is provided as an annular film structure surrounding the inner side surface of the composite shell 1 and the end surface of the opening 13, and the seal 4 can have a certain overlap with the shell insulating layer 12 to ensure the sealing and insulation effect between the cover plate 2 and the composite shell 1. Of course, the seal 4 can also be butted with the shell insulating layer 12 without overlapping, and the sealing and insulation effect between the cover plate 2 and the composite shell 1 can also be ensured.

[0058] The compression rate of the seal 4 is greater than or equal to 12% and less than or equal to 38%. For example, the compression rate of the seal 4 can be 15%, 17%, 20%, 23%, 25%, 28%, 30%, 32%, 35%, 37% and so on.

[0059] Compression rate is also called compressive strain, which indicates the change of the original unit height of the specimen, expressed as a ratio of the same dimension. It can also be said that the compression rate is the increment of the original unit length of the gauge under the action of compressive stress (i.e. the rate of change of length), expressed as a percentage (%).

[0060] The compression rate test method is to apply a measurable load to the end surface of the sample along the main axis direction at a constant rate to compress the sample until the sample breaks, yields, or the sample deformation reaches a predetermined number. The sample and the test method are based on national standards. Specifically, the sample is placed between the surfaces of the two pressure plates, and the center line of the sample coincides with the center line connecting the two pressure plate surfaces. Ensure that the end face of the sample is parallel to the pressure plate surface, adjust the testing machine so that the pressure plate surface just contacts the end face of the sample, and locate the zero point of the test deformation at this time. Adjust the test speed according to the material regulations. If there is no regulation, adjust the speed to 1mm / min. Record the load and corresponding compression strain at the appropriate strain interval.

[0061] If the compression rate of the seal 4 is too small, the effective deformation of the seal 4 is too small, and the sealing effect of the seal 4 cannot be guaranteed. If the compression rate of the seal 4 is too large, the deformation of the seal 4 is too large, and the strength of the rolled edge connection structure 3 cannot be guaranteed.

[0062] The above numerical range not only ensures the sealing effect of the seal 4 , but also ensures the strength of the rolled edge connection structure 3 .

[0063] Reference Figure 4 As shown, in this exemplary embodiment, the shell insulating layer 12 can be arranged on the inner surface of the shell metal layer 11, that is, the shell insulating layer 12 is arranged closer to the battery cell 5 relative to the shell metal layer 11, so that the cover plate 2 and the shell metal layer 11 are already insulated and isolated by the shell insulating layer 12; the shell insulating layer 12 can increase the ability of the composite shell 1 to resist electrolyte corrosion, and increase the insulation effect between the composite shell 1 and the battery cell 5. In this case, the seal 4 is not arranged to exceed the roll edge connection structure 3, that is, the edge of the seal 4 can be flush with the edge of the roll edge connection structure 3, or the edge of the roll edge connection structure 3 can protrude from the edge of the seal 4. The seal 4 covers a smaller area of ​​the cover plate 2 to ensure the heat dissipation area of ​​the cover plate 2.

[0064] Of course, in some other exemplary embodiments of the present disclosure, reference Figure 3 As shown, the shell insulating layer 12 can be arranged on the outer surface of the shell metal layer 11, that is, the shell metal layer 11 is arranged closer to the battery cell 5 than the shell insulating layer 12, and the shell insulating layer 12 can increase the insulation effect between the composite shell 1 and other external components. In this case, since there is no insulation arrangement between the cover plate 2 and the shell metal layer 11, the seal 4 is arranged beyond the rolled edge connection structure 3, and the seal 4 not only plays a sealing effect between the cover plate 2 and the composite shell 1, but also plays an insulation effect between the cover plate 2 and the composite shell 1.

[0065] Reference Figure 3 and Figure 4 As shown, a limiting structure 14 is provided on the side of the composite shell 1 close to the battery cell 5, that is, a limiting structure 14 is provided on the inner side wall of the composite shell 1, and the limiting structure 14 and the composite shell 1 can be an integrally formed structure, that is, the limiting structure 14 is formed while the composite shell 1 is formed by a stretching or stamping process. The edge portion 21 is arranged on the limiting structure 14, that is, the edge portion 21 is arranged on the side of the limiting structure 14 away from the battery cell 5. The cover plate 2 can be limited by the limiting structure 14 to avoid movement of the cover plate 2 during the hemming process, avoid affecting the volume of the composite shell 1, and thus avoid affecting the energy density of the battery cell; and make the multiple battery cells produced maintain consistency.

[0066] Reference Figure 4As shown, in this exemplary embodiment, the housing insulating layer 12 can be arranged on the inner surface of the housing metal layer 11, that is, the housing insulating layer 12 is arranged closer to the battery cell 5 relative to the housing metal layer 11, so that the cover plate 2 and the housing metal layer 11 are insulated and isolated by the housing insulating layer 12; in this case, the seal 4 is arranged not to exceed the limiting structure 14, that is, the edge of the seal 4 can be flush with the edge of the limiting structure 14, or the edge of the limiting structure 14 can protrude from the edge of the seal 4. Similarly, the area covered by the seal 4 on the cover plate 2 can be made smaller to ensure the heat dissipation area of ​​the cover plate 2.

[0067] Of course, in some other exemplary embodiments of the present disclosure, reference Figure 3 As shown, the shell insulating layer 12 can be arranged on the outer surface of the shell metal layer 11, that is, the shell metal layer 11 is arranged closer to the battery cell 5 relative to the shell insulating layer 12, and the shell insulating layer 12 can increase the insulation effect between the composite shell 1 and other external components; in this case, since there is no insulation arrangement between the cover plate 2 and the shell metal layer 11, the seal 4 is arranged beyond the limiting structure 14, and the seal 4 not only has a sealing effect between the cover plate 2 and the composite shell 1, but also has an insulation effect between the cover plate 2 and the composite shell 1.

[0068] In this example implementation, refer to Figure 3 As shown, the sealing width K of the seal 4 is greater than or equal to 2 mm and less than or equal to 15 mm. For example, the sealing width K of the seal 4 can be 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, and the like.

[0069] If the sealing width K of the sealing member 4 is too small, the sealing member 4 will not be able to ensure the sealing effect between the cover plate 2 and the composite shell 1 .

[0070] If the sealing width K of the seal 4 is too large, the seal 4 covers a larger area of ​​the cover plate 2 and the heat dissipation area of ​​the cover plate 2 cannot be guaranteed. In addition, the seal 4 occupies a larger space in the composite shell 1, which is not conducive to improving the space utilization rate of the composite shell 1.

[0071] Within the above numerical range, the seal 4 can not only ensure the sealing effect between the cover plate 2 and the composite shell 1 , but also ensure the heat dissipation area of ​​the cover plate 2 and the space utilization of the composite shell 1 .

[0072] It should be noted that the seal 4 is provided in a ring shape, and the sealing width K of the seal 4 refers to the ring width of the seal 4 .

[0073] Of course, in some other exemplary embodiments of the present disclosure, reference Figure 2 As shown, the shell insulating layer 12 is arranged on the inner surface of the shell metal layer 11, that is, the shell insulating layer 12 is arranged closer to the battery cell 5 relative to the shell metal layer 11. In this case, the cover plate 2 and the shell insulating layer 12 can be directly contacted and connected, and the cover plate 2 and the shell metal layer 11 can be insulated and isolated by the shell insulating layer 12. There is no need to set up an additional insulating layer, nor is there any need to seal the cover plate 2 and the shell metal layer 11 through the seal 4. The shell insulating layer 12 can have a sealing effect.

[0074] In this example embodiment, the wall thickness H1 of the housing insulating layer 12 is less than or equal to 0.16 mm. For example, the wall thickness H1 of the housing insulating layer 12 may be 0.05 mm, 0.07 mm, 0.09 mm, 0.1 mm, 0.12 mm, 0.14 mm, etc.

[0075] If the wall thickness H1 of the shell insulating layer 12 is too thick, it is easy to cause the sealing between the cover plate 2 and the composite shell 1 to fail, and the shell insulating layer 12 occupies a large space inside the composite shell 1, which is not conducive to improving the space utilization of the composite shell 1, nor is it conducive to improving the energy density of the battery cell.

[0076] The above numerical range not only ensures the sealing effect between the cover plate 2 and the composite shell 1, but also helps to improve the space utilization of the composite shell 1 and the energy density of the battery cell.

[0077] The ratio of the thickness H2 of the cover plate 2 to the wall thickness H3 of the composite shell 1 is greater than or equal to 1.5 and less than or equal to 4. For example, the ratio of the thickness H2 of the cover plate 2 to the wall thickness H3 of the composite shell 1 can be 1.7, 2, 2.2, 2.5, 2.7, 3, 3.3, 3.5, 3.8, etc.

[0078] If the ratio of the thickness H2 of the cover plate 2 to the wall thickness H3 of the composite shell 1 is too large, resulting in the wall thickness H3 of the composite shell 1 being too small, the risk of deformation of the composite shell 1 is relatively high.

[0079] If the ratio of the thickness H2 of the cover plate 2 to the wall thickness H3 of the composite shell 1 is too small, resulting in the thickness H2 of the cover plate 2 being too small, the risk of deformation of the cover plate 2 is relatively high.

[0080] The above numerical range not only ensures that the deformation risk of the composite shell 1 is small, but also that the deformation risk of the cover plate 2 is small, so as to ensure the overall strength of the battery cell.

[0081] It should be noted that the thickness H2 of the cover plate 2 and the wall thickness H3 of the composite shell 1 both refer to the thickness of the solid part, and do not include the thickness of other protruding structures; for example, when a concave and convex reinforcement structure is provided on the cover plate, the thickness H2 of the cover plate 2 does not include the thickness of the reinforcement structure; when a limiting structure 14 is provided on the composite shell 1, the wall thickness H3 of the composite shell 1 does not include the height of the limiting structure 14.

[0082] Reference Figure 2 and Figure 5 As shown, in this exemplary embodiment, the cover plate 2 can be an output pole of the battery cell. For example, the cover plate 2 can be connected to the negative pole ear 53 of the battery cell 5, so that the cover plate 2 is the negative pole of the battery cell. Specifically, the cover plate 2 and the negative pole ear 53 of the battery cell 5 can be connected through a negative current collector. Of course, the cover plate 2 can be connected to the positive pole ear 52 of the battery cell 5. Specifically, the cover plate 2 and the positive pole ear 52 of the battery cell 5 can be connected through a positive current collector, so that the cover plate 2 is the positive pole of the battery cell.

[0083] Reference Figure 4 As shown, in some other exemplary embodiments of the present disclosure, an output pole of a battery cell is insulated and connected to the cover plate 2. For example, a through hole can be provided on the cover plate 2, and a battery pole 6 runs through the through hole. One end of the battery pole 6 can be connected to the positive pole ear 52 of the battery cell 5, so that the battery pole 6 is the positive pole of the battery cell. Of course, one end of the battery pole 6 can be connected to the negative pole ear 53 of the battery cell 5, so that the battery pole 6 is the negative pole of the battery cell.

[0084] In addition, in some other exemplary embodiments of the present disclosure, the cover plate 2 may be an output pole of the battery cell. For example, the cover plate 2 may be connected to the negative pole ear 53 of the battery cell 5, so that the cover plate 2 is the negative pole of the battery cell. Specifically, the cover plate 2 and the negative pole ear 53 of the battery cell 5 may be connected through a negative current collector. Moreover, an output pole of the battery cell is insulated and connected to the cover plate 2. For example, a through hole may be provided on the cover plate 2, and a battery pole 6 may be passed through the through hole. One end of the battery pole 6 may be connected to the positive pole ear 52 of the battery cell 5, so that the battery pole 6 is the positive pole of the battery cell.

[0085] 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.

[0086] 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 battery cell, characterized in that: include: A composite shell, comprising a stacked shell metal layer and a shell insulating layer, wherein the shell metal layer and the shell insulating layer are an integrally formed structure, the composite shell has an opening, and the opening is configured as a two-layer structure including the shell metal layer and the shell insulating layer, and the tensile strength of the shell metal layer is greater than or equal to 120 MPa and less than or equal to 200 MPa; A cover plate, covering the opening, wherein the cover plate has an edge portion; The rolled edge connection structure is arranged at the edge portion and the opening portion.

2. The battery cell according to claim 1, characterized in that: The battery cell further comprises: A sealing member is disposed between the edge portion and the opening portion.

3. The battery cell according to claim 2, characterized in that: The compression rate of the sealing element is greater than or equal to 12% and less than or equal to 38%.

4. The battery cell according to claim 2, characterized in that: The shell insulation layer is arranged on the inner surface of the shell metal layer, and the sealing component does not exceed the rolling connection structure; or, the shell insulation layer is arranged on the outer surface of the shell metal layer, and the sealing component exceeds the rolling connection structure.

5. The battery cell according to claim 2, characterized in that: A limiting structure is arranged on one side of the composite shell close to the battery core, and the edge portion is placed on the limiting structure.

6. The battery cell according to claim 5, characterized in that: The shell insulation layer is arranged on the inner surface of the shell metal layer, and the sealing component does not exceed the limiting structure; or, the shell insulation layer is arranged on the outer surface of the shell metal layer, and the sealing component exceeds the limiting structure.

7. The battery cell according to claim 2, characterized in that: The sealing width of the sealing member is greater than or equal to 2 mm and less than or equal to 15 mm.

8. The battery cell according to claim 1, characterized in that: The shell insulating layer is arranged on the inner surface of the shell metal layer, and the cover plate is directly in contact with and connected to the shell insulating layer.

9. The battery cell according to any one of claims 1 to 8, characterized in that: The wall thickness of the shell insulation layer is less than or equal to 0.16 mm.

10. The battery cell according to any one of claims 1 to 8, characterized in that: The ratio of the thickness of the cover plate to the wall thickness of the composite shell is greater than or equal to 1.5 and less than or equal to 4.

11. The battery cell according to any one of claims 1 to 8, characterized in that: The cover plate is an output pole of the battery cell, and / or an output pole of the battery cell is insulated and connected to the cover plate.

12. The battery cell according to any one of claims 1 to 8, characterized in that: The battery cell is a cylindrical battery.

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