A cylindrical battery and its casing
By designing a cylindrical battery casing with gradually varying wall thickness, and using thickened sections and stepped structures to enhance the axial and circumferential constraints between the core and the casing, the problem of relative displacement between the core and the casing under mechanical impact is solved, thereby improving the safety and structural stability of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGSU TENPOWER LITHIUM
- Filing Date
- 2026-03-12
- Publication Date
- 2026-06-30
AI Technical Summary
In mechanical impact and drop tests, existing cylindrical lithium-ion batteries are prone to relative displacement between the core and the casing, leading to mechanical damage and safety hazards. Furthermore, the existing expansion tape has insufficient restraint and cannot effectively restrict the axial and circumferential movement of the core.
A cylindrical battery casing is designed, including a sidewall structure with gradually varying wall thickness, and first and second thickened sections and a stepped structure to enhance the axial and circumferential constraint force between the core and the casing. An expansion tape is used to increase the contact stress and limiting effect at the thickened sections.
In scenarios involving drops and vibrations, the insulation enhances the fixation between the core and the casing, effectively limiting the axial movement and circumferential rotation of the core, thereby improving the structural integrity and safety performance of the battery.
Smart Images
Figure CN121812845B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery technology, and more particularly to a cylindrical battery and its casing. Background Technology
[0002] With the widespread application of cylindrical lithium-ion batteries in electric vehicles, power tools, and energy storage systems, the operating environments they face are becoming increasingly complex and demanding, especially with ever-increasing safety requirements for resistance to mechanical shocks and drops. Industry-standard reliability tests, such as roller drop tests, aim to simulate the impacts and vibrations that batteries may experience during transportation, assembly, and use, and their testing standards are becoming increasingly stringent. In these tests, if relative displacement or loosening occurs between the battery's internal core and casing, it can easily lead to mechanical damage such as electrode tearing, separator damage, and internal short circuits, potentially triggering serious safety hazards such as thermal runaway.
[0003] Currently, the industry commonly uses a method of attaching a ring-shaped expansion tape or similar cushioning material between the core and the casing. The tape absorbs liquid and fills the gap, attempting to fix the core and buffer vibrations. However, this method has significant limitations: its main functionality relies on the combined effect of the gap between the core and the casing and the expansion of the tape to achieve reliability. In actual cell design, the casing outer diameter is determined by customer requirements, and the assembly gap is determined by the manufacturability of the cell manufacturing process. Simultaneously, cell development trends pursue high energy density. Under these defined boundary conditions, there is no room for independent design of the expansion tape thickness and the casing sidewall thickness. Given the limitations of traditional solutions, there is an urgent need to develop a more reliable, stable, and space-efficient core-casing fixing technology to improve the structural integrity and safety performance of cylindrical batteries under harsh mechanical loads.
[0004] In existing steel shell technology, the wall thickness of the sealing area is greater than that of the main body. However, the connection structure between the two is a smooth transition and there is no stepped structure, so it does not have axial limiting or restraining effects. Summary of the Invention
[0005] The inventors discovered that current cylindrical battery cells have certain boundary limitations on the outer diameter of the core to ensure smooth insertion into the steel shell during the manufacturing process. The assembly gap between the core and the steel shell is a design structural feature that satisfies the manufacturability of the battery cell. To prevent relative movement between the core and the steel shell under certain mechanical actions caused by the assembly gap, an expansion tape is designed to wrap the outer layer of the core structure. The expansion tape absorbs liquid and expands to fill the gap between the lithium-ion battery core and the steel shell. The friction mechanism between the expansion tape on the core and the steel shell prevents axial movement and circumferential displacement of the core and the steel shell in the battery cell under certain special service conditions.
[0006] For designs aimed at preventing axial movement of the battery cell relative to the steel shell, the constraint force of the expansion tape alone is insufficient due to the significant weight of the core. Therefore, another current measure to prevent axial movement of the core is to use a grooving structure placed horizontally above the core and upper gasket, physically isolating it to constrain larger-scale axial movement relative to the shell. However, the grooving structure's axial constraint on the core is insufficient for limiting smaller-scale axial movement. This is primarily because current mainstream cylindrical battery cell designs use a diaphragm-covered electrode, with the diaphragm wider than the electrode. To prevent the diaphragm from squeezing the electrode, a certain amount of redundant space needs to be designed for diaphragm compression. This inherent structure means that the current grooving structure cannot restrict small-range axial movement of the core. Therefore, given the insufficient friction from the expansion tape and the inadequacy of the grooving design for limiting small-scale movement, it is necessary to develop related structures and technologies to achieve more reliable axial constraint of the core relative to the steel shell.
[0007] For the circumferential rotational movement of the battery cell relative to the steel shell, such as in service environments like drum tests, the constraint force of the expansion tape depends on the amount of expansion tape on the core within a certain range. Given a limited gap between the inner diameter of the steel shell and the core, the more expansion tape wrapped around the core, the smaller the space available for electrode materials, which contradicts the current trend of high energy density in battery cell development. Therefore, a related structure or technology needs to be designed to increase the circumferential constraint force between the core and the steel shell to ensure that the core and steel shell do not undergo circumferential movement under certain special service environments.
[0008] In view of the shortcomings of the prior art, one object of this specification is to provide a cylindrical battery and its casing that can increase the circumferential constraint force between the core and the casing, and achieve more reliable axial constraint between the core and the casing.
[0009] To achieve the above objectives, this specification provides a cylindrical battery casing, comprising: a connected sidewall and a bottom wall, wherein the sidewall includes an opening segment, a first thickened segment, a main body segment and a bottom segment connected sequentially in the axial direction, the opening segment being away from the bottom wall, and the bottom segment being connected to the bottom wall; the main body segment extending along the axial direction;
[0010] The wall thickness of the opening section is greater than the wall thickness of the first thickened section, the wall thickness of the first thickened section is greater than the wall thickness of the main body section, and the wall thickness of the bottom section is greater than the wall thickness of the main body section.
[0011] A first step is provided between the opening section and the first thickened section to limit the movement of the core with the expansion tape.
[0012] In a preferred embodiment, the wall thickness of the opening segment is 1.1 to 2 times the wall thickness of the main body segment; the wall thickness of the first thickened segment is 1.1 to 1.8 times the wall thickness of the main body segment.
[0013] In a preferred embodiment, in the initial state, the angle between the opening segment and the axial direction is 0~10°, and the angle between the first thickened segment and the axial direction is 0~10°.
[0014] In a preferred embodiment, the first step and the first thickened section form a first angle, the first angle being in the range of 90° to 110°.
[0015] In a preferred embodiment, in the initial state, the first step and the opening segment extend outward toward the sidewall; after the opening narrows, the first step and the opening segment extend inward toward the sidewall.
[0016] In a preferred embodiment, a second step is provided between the main body segment and the bottom segment. The second step and the first step are used together to limit the core with the expansion tape.
[0017] In a preferred embodiment, a second thickened section is further included between the main body section and the bottom section, the wall thickness of the second thickened section being greater than the wall thickness of the main body section, and the wall thickness of the bottom section being greater than the wall thickness of the second thickened section; the second step is disposed between the second thickened section and the bottom section; both the second thickened section and the bottom section extend along the axial direction.
[0018] In a preferred embodiment, the wall thickness of the second thickened section is 1.1 to 1.8 times that of the main body section; and the wall thickness of the bottom section is 1.1 to 2 times that of the main body section.
[0019] In a preferred embodiment, the second step and the second thickened section form a second included angle, the second included angle being in the range of 90° to 110°.
[0020] This application also provides a cylindrical battery, comprising:
[0021] The housing as described in any of the above embodiments;
[0022] The core is disposed inside the housing and the core is wrapped with expansion tape; after the end is narrowed, the positive end of the expansion tape is limited by the first step of the housing;
[0023] A cap is disposed at the positive end of the core, and the cap is fixedly connected to the opening section of the housing. Beneficial effects
[0024] The cylindrical battery casing provided in this embodiment has a first thickened section with a wall thickness greater than that of the main body section. This first thickened section corresponds to the expansion tape at the positive end of the core. After the cylindrical battery is sealed and formed, the gap between the first thickened section and the core is reduced. After the expansion tape absorbs liquid and expands, the contact stress at the first thickened section increases. Therefore, in some application scenarios such as drops, vibrations, and rotations, the relative constraint force (circumferential constraint force) between the core and the casing can be further increased, and the casing and the core can be better fixed.
[0025] Meanwhile, a first step is set at the corresponding position of the opening section of the housing. After the battery cell is assembled, one end of the expansion tape outside the core can be limited by the first step, thereby preventing small axial movement between the core and the housing under service environments such as drops and vibrations, and achieving more reliable axial constraint between the core and the housing.
[0026] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.
[0027] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.
[0028] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 This is a schematic diagram of the structure of a shell provided in this embodiment;
[0031] Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure of the AA surface in the middle;
[0032] Figure 3 for Figure 2 Enlarged structural diagram at point B;
[0033] Figure 4 for Figure 3Enlarged structural diagram at point D;
[0034] Figure 5 for Figure 2 Enlarged structural diagram at point C;
[0035] Figure 6 for Figure 5 Enlarged structural diagram at point E;
[0036] Figure 7 for Figure 1 The diagram shows the structure after the core is inserted into the housing.
[0037] Figure 8 for Figure 7 A schematic diagram of the cross-sectional structure of the FF surface;
[0038] Figure 9 for Figure 8 A magnified structural diagram at point G in the middle;
[0039] Figure 10 for Figure 9 Enlarged structural diagram at point I;
[0040] Figure 11 for Figure 8 Enlarged structural diagram at point H;
[0041] Figure 12 for Figure 11 Enlarged structural diagram at point J;
[0042] Figure 13 for Figure 7 A schematic diagram of the structure after the necking process;
[0043] Figure 14 for Figure 13 A schematic diagram of the cross-sectional structure of the KK surface;
[0044] Figure 15 for Figure 14 Enlarged structural diagram at point M;
[0045] Figure 16 for Figure 15 A magnified structural diagram at point N;
[0046] Figure 17 This is a schematic diagram of the structure of a cylindrical battery provided in this embodiment;
[0047] Figure 18 for Figure 17 A schematic diagram of the cross-sectional structure of the PP surface;
[0048] Figure 19 for Figure 18 Enlarged structural diagram at point Q;
[0049] Figure 20 for Figure 19 Enlarged structural diagram at point S;
[0050] Figure 21 for Figure 18 Enlarged structural diagram at point R in the middle;
[0051] Figure 22 for Figure 21 A magnified structural diagram at point T.
[0052] Explanation of reference numerals in the attached figures:
[0053] 100. Cylindrical battery; 1. Casing; 11. Side wall; 111. Opening section; 112. First thickened section; 113. Main body section; 114. Second thickened section; 115. Bottom section; 116. First step; 117. Second step; 12. Bottom wall; 2. Core; 21. Expansion tape; 3. Cap; 4. Positive electrode gasket; 5. Negative electrode gasket;
[0054] α, First included angle; β, Second included angle; t, Wall thickness of the main body section; t1, Wall thickness of the first thickened section; t2, Wall thickness of the opening section; t3, Wall thickness of the second thickened section; t4, Wall thickness of the bottom section; L1, Distance from the first step to the top of the shell; L2, Distance from the intersection of the first thickened section and the main body section to the top of the shell; L3, Distance from the second step to the bottom of the shell; L4, Distance from the intersection of the second thickened section and the main body section to the bottom of the shell; L5, Distance between the positive end of the expansion tape and the upper edge of the positive electrode coating area; L6, Distance between the negative end of the expansion tape and the lower edge of the positive electrode coating area; L7, Spacing between the positive and negative edges of the expansion tape; L8, Spacing between the first step and the second step; X, Axial direction. Detailed Implementation
[0055] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.
[0056] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.
[0057] 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 in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0058] Please see Figures 1 to 6 This application provides a casing 1 for a cylindrical battery 100, including a connected side wall 11 and a bottom wall 12. This application does not impose a single limitation on the material of the casing 1, but it is preferably a steel casing.
[0059] The sidewall 11 includes an opening segment 111, a first thickened segment 112, a main body segment 113, and a bottom segment 115 connected sequentially along the axial direction X. The opening segment 111 is away from the bottom wall 12, and the bottom segment 115 is connected to the bottom wall 12. The main body segment 113 extends along the axial direction X. The wall thickness t2 of the opening segment 111 is greater than the wall thickness t1 of the first thickened segment 112, the wall thickness t1 of the first thickened segment 112 is greater than the wall thickness t of the main body segment 113, and the wall thickness t4 of the bottom segment 115 is greater than the wall thickness t of the main body segment 113. A first step 116 is provided between the opening segment 111 and the first thickened segment 112 to limit the movement of the core 2 with the expanding adhesive tape 21.
[0060] The cylindrical battery 100 housing 1 provided in this embodiment has a first thickened section 112 with a wall thickness greater than that of the main body section 113. The first thickened section 112 corresponds to the expansion tape 21 at the positive end of the core 2. After the cylindrical battery 100 is sealed and formed, the gap between the first thickened section 112 and the core 2 is reduced. After the expansion tape 21 absorbs liquid and expands, the contact stress at the first thickened section 112 increases. Therefore, in some application scenarios such as drops, vibrations, and rotations, the relative constraint force (circumferential constraint force) between the core 2 and the housing 1 can be further increased, and the housing 1 and the core 2 can be better fixed.
[0061] Meanwhile, the housing 1 has a first step 116 at the corresponding position of the opening section 111. After the battery cell is assembled, one end of the expansion tape 21 outside the core 2 can be limited by the first step 116, thereby preventing the core 2 and the housing 1 from moving slightly in the axial direction X under some service environments such as drops and vibrations, and achieving more reliable axial X constraint between the core 2 and the housing 1.
[0062] In this embodiment, such as Figure 3 As shown, the wall thickness t2 of the opening section 111 is 1.1 to 2 times the wall thickness t of the main body section 113. In the initial state, the angle between the opening section 111 and the axial direction X is 0 to 10°, meaning the opening section 111 can extend along the axial direction X or have an angle less than or equal to 10° with it. When the opening section 111 has an angle with the axial direction X, the distance between the opening section 111 and the central axis of the main body section 113 increases in the axial direction X, meaning the opening section 111 is in an open state, facilitating the insertion of the core 2 into the shell. In this application, "initial state" refers to the state before the necking process.
[0063] like Figure 3 As shown, the wall thickness t1 of the first thickened section 112 is 1.1 to 1.8 times the wall thickness t of the main body section 113. Initially, the angle between the first thickened section 112 and the axial direction X is 0 to 10°, meaning the first thickened section 112 can extend along the axial direction X or have an angle less than or equal to 10° with it. When the first thickened section 112 has an angle with the axial direction X, the distance between the first thickened section 112 and the central axis of the main body section 113 increases along the axial direction X, meaning the first thickened section 112 is in an open state, facilitating the insertion of the core 2 into the shell.
[0064] like Figure 4 As shown, the first step 116 and the first thickened section 112 form a first included angle α, which ranges from 90° to 110°. An excessively large α will result in poor limiting effect. Specifically, in the initial state, the first step 116 and the opening section 111 extend outwards from the side wall 11. Combined with the angle between the opening section 111 and the first thickened section 112 and the axial direction X, this facilitates the insertion of the core 2 into the shell. Figure 16 As shown, after the opening narrows, the first step 116 and the opening segment 111 extend inward toward the side wall 11.
[0065] In this embodiment, such as Figure 5 and Figure 6As shown, a second step 117 is provided between the main body section 113 and the bottom section 115. The second step 117 and the first step 116 are used together to limit the core 2 with the expansion tape 21. The housing 1 is provided with the first step 116 and the second step 117 at corresponding positions on the opening section 111 and the bottom section 115, respectively, and limits the distance L7 between the positive and negative edges of the expansion tape 21 to be less than or equal to the distance L8 between the first step 116 and the second step 117 (e.g., ...). Figure 14 As shown in the figure, after the battery cell is assembled, the expansion tape 21 absorbs liquid and expands, and is located between the first step 116 and the second step 117, thus forming an assembly structure that can prevent small axial movement between the core 2 and the housing 1.
[0066] like Figure 5 and Figure 6 As shown, a second thickened section 114 is also included between the main body section 113 and the bottom section 115. The wall thickness t3 of the second thickened section 114 is greater than the wall thickness t of the main body section 113, and the wall thickness t4 of the bottom section 115 is greater than the wall thickness t3 of the second thickened section 114. A second step 117 is disposed between the second thickened section 114 and the bottom section 115. Both the second thickened section 114 and the bottom section 115 extend along the axial direction X.
[0067] By setting a second thickened section 114 with a wall thickness greater than that of the main section 113, the second thickened section 114 corresponds to the expansion tape 21 at the negative end of the core 2. After the cylindrical battery 100 is sealed and formed, the gap between the second thickened section 114 and the core 2 is reduced. After the expansion tape 21 absorbs liquid and expands, the contact stress at the second thickened section 114 increases. Thus, in some application scenarios such as drops, vibrations, and rotations, the relative constraint force (circumferential constraint force) between the core 2 and the shell 1 can be further increased, and the shell 1 and the core 2 can be better fixed.
[0068] Specifically, such as Figure 5 and Figure 6 As shown, the wall thickness t3 of the second thickened section 114 is 1.1 to 1.8 times the wall thickness t of the main section 113. The wall thickness t4 of the bottom section 115 is 1.1 to 2 times the wall thickness t of the main section 113.
[0069] like Figure 6As shown, the second step 117 and the second thickened section 114 form a second included angle β, which ranges from 90° to 110°. An excessively large β will result in poor limiting effect. The bottom section 115 and the bottom wall 12 are connected by a rounded transition. The connections between the first thickened section 112 and the main body section 113, and between the second thickened section 114 and the main body section 113, are smooth transitions. Specifically, the wall thickness of the portion connecting the first thickened section 112 and the main body section 113 gradually decreases until it equals the wall thickness t of the main body section 113; similarly, the wall thickness of the portion connecting the second thickened section 114 and the main body section 113 gradually decreases until it equals the wall thickness t of the main body section 113.
[0070] like Figure 3 As shown, the distance from the first step 116 to the top of the shell 1 is L1, and the distance from the intersection of the first thickened section 112 and the main body section 113 to the top of the shell 1 is L2. L2-L1 is the axial length of the first thickened section 112, which is also the axial length of the extrusion reinforcement zone Z1 described below. Figure 5 As shown, the distance from the second step 117 to the bottom of the shell 1 is L3, and the distance from the intersection of the second thickened section 114 and the main body section 113 to the bottom of the shell 1 is L4. L4-L3 is the axial length of the second thickened section 114, which is also the axial length of the extrusion reinforcement zone Z2 described below.
[0071] Please see Figures 7 to 22 This application also provides a cylindrical battery 100, including: a casing 1, a winding core 2, and a cap 3.
[0072] The housing 1 can be any of the housing 1 described in the above embodiments. The core 2 is disposed inside the housing 1. The core 2 is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet. The core 2 is wrapped with an expansion tape 21. The expansion tape 21 can be a fully enclosed structure extending from the positive electrode side to the negative electrode side of the core 2, or it can be a separate structure with separate positive and negative electrode sides. After the opening is narrowed, the positive end of the expansion tape 21 is limited by the first step 116 of the housing 1. Further, as... Figure 14 As shown, after the opening is narrowed, the distance L7 between the positive and negative edges of the expansion tape 21 is less than or equal to the distance L8 between the first step 116 and the second step 117 of the housing 1. The cap 3 is located at the positive end of the core 2, and the cap 3 is fixedly connected to the opening section 111 of the housing 1.
[0073] like Figure 10 As shown, the distance between the positive terminal of the expansion tape 21 and the upper edge of the positive electrode coating area is L5, where L5 ≥ 0. That is, the upper edge of the positive electrode coating area extends beyond the positive terminal of the expansion tape 21, or is flush with it. Figure 12As shown, the distance between the negative end of the expansion tape 21 and the lower edge of the positive electrode coating area is L6, where L6≥0. That is, the lower edge of the positive electrode coating area extends beyond the negative end of the expansion tape 21, or is flush with the negative end of the expansion tape 21. Preferably, L5=L6, in which case the application of the expansion tape 21 is symmetrical.
[0074] like Figure 18 As shown, the cylindrical battery 100 also includes a positive electrode pad 4 disposed on the positive end face of the winding core 2 and a negative electrode pad 5 disposed on the negative end face of the winding core 2, which are used to protect the positive end face and the negative end face of the winding core 2, respectively. The positive electrode pad 4 is located between the winding core 2 and the cap 3, and the negative electrode pad 5 is located between the winding core 2 and the bottom wall 12 of the casing 1.
[0075] In a specific application scenario, the assembly process of the cylindrical battery 100 is as follows:
[0076] First, insert the core 2 into the housing 1 with its negative end facing the bottom wall 12. After assembly, the edge of the expansion tape 21 of the negative end of the core 2 forms a shape with the bottom section 115 of the side wall 11 of the housing 1. Figure 12 The mating structure is shown. After assembly, the distance between the expansion tape 21 on the core 2 and the outermost edge of the bottom wall 12 is equal to the distance between the second step 117 and the outermost edge of the bottom wall 12, both being L3.
[0077] Then, a necking process is performed on the opening of the cylindrical battery 100. After necking, the first step 116 forms a gap with the positive end expansion tape 21 of the core 2. Figure 16 The mating structure shown here, where the first thickened section 112 used for limiting undergoes plastic deformation, is formed by... Figure 10 The first thickened segment 112 shown extends outward and transforms into the shape of... Figure 16 The first thickened section 112 extends inward, at which point the distance L7 between the positive and negative edges of the expansion tape 21 is less than or equal to the distance L8 between the first step 116 and the second step 117.
[0078] After the cylindrical battery 100 is formed into a finished product, the expansion tape 21 absorbs liquid and expands fully to form the final shape as shown. Figures 18 to 22 As shown. The positive and negative edges of the expansion tape 21 are positioned between the first step 116 and the second step 117 to provide axial X-constraint for the core 2. Figure 19 and Figure 21 As shown, the expansion tape 21 forms a conventional circumferential constraint with the main body segment 113. (As indicated...) Figures 19 to 22 As shown, the first thickened section 112 and the second thickened section 114 of the shell 1 have increased wall thickness relative to the main body section 113, and the core 2 at both locations is compressed (the expansion tape 21 and the first thickened section 112 form a compression reinforcement zone Z1, and the expansion tape 21 and the second thickened section 114 form a compression reinforcement zone Z2), thus enhancing the circumferential constraint of the shell 1.
[0079] In the prior art, the first thickened section 112 and / or the second thickened section 114 are not provided; instead, the main body section 113 is still provided at the positions of the first thickened section 112 and the second thickened section 114. In this application, as analyzed above, the first thickened section 112 and the second thickened section 114 can form the extrusion reinforcement region Z1 and the extrusion reinforcement region Z2 to enhance the circumferential constraint of the shell 1.
[0080] However, this application does not designate the entire section between the first step 116 and the second step 117 as a thickened section capable of forming a compression-enhanced region. Instead, it retains a relatively thin main body section 113 between the first thickened section 112 and the second thickened section 114. This is because if the entire section were designed as a thickened section, it would be difficult to insert the core 2 into the casing. Furthermore, given that the outer diameter of the cylindrical battery 100 (e.g., 18650 and 21700 batteries) remains unchanged, and the current trend is to increase volumetric energy density and mass energy density, it is necessary to reduce the wall thickness of the casing 1 and increase the diameter of the core 2. Considering the technical problem to be solved by this application, only a partial thickened section can be provided (e.g., in this embodiment, the first thickened section 112 and the second thickened section 114 are provided on both sides of the main body section 113), rather than increasing the overall wall thickness of the casing 1. This contradicts the original design intention of increasing the volumetric energy density and mass energy density of the cylindrical battery.
[0081] It should be noted that in the description of this specification, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this specification, unless otherwise stated, "a plurality of" means two or more.
[0082] Any numerical values cited herein include all values ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values listed between the minimum and maximum values are explicitly described in this specification in a similar manner.
[0083] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.
[0084] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.
[0085] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.
[0086] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.
Claims
1. A casing for a cylindrical battery, characterized in that, include: The sidewalls and bottom wall are connected, the sidewalls comprising an opening segment, a first thickened segment, a main body segment and a bottom segment connected sequentially in the axial direction, the opening segment being away from the bottom wall, the bottom segment being connected to the bottom wall; the main body segment extending along the axial direction; The wall thickness of the opening section is greater than the wall thickness of the first thickened section, the wall thickness of the first thickened section is greater than the wall thickness of the main body section, and the wall thickness of the bottom section is greater than the wall thickness of the main body section. A first step is provided between the opening section and the first thickened section to limit the movement of the core with the expansion tape.
2. The housing according to claim 1, characterized in that, The wall thickness of the opening section is 1.1 to 2 times that of the main body section; the wall thickness of the first thickened section is 1.1 to 1.8 times that of the main body section.
3. The housing according to claim 1, characterized in that, In the initial state, the angle between the opening segment and the axis is 0~10°, and the angle between the first thickened segment and the axis is 0~10°.
4. The housing according to claim 1, characterized in that, The first step and the first thickened section form a first angle, the first angle being 90° to 110°.
5. The housing according to claim 1, characterized in that, In the initial state, the first step and the opening segment extend outward toward the sidewall; after the opening narrows, the first step and the opening segment extend inward toward the sidewall.
6. The housing according to claim 1, characterized in that, A second step is provided between the main body section and the bottom section. The second step and the first step are used together to limit the core with the expansion tape.
7. The housing according to claim 6, characterized in that, The main body segment and the bottom segment are further divided into a second thickened segment, the wall thickness of which is greater than that of the main body segment, and the wall thickness of the bottom segment is greater than that of the second thickened segment; the second step is disposed between the second thickened segment and the bottom segment; both the second thickened segment and the bottom segment extend along the axial direction.
8. The housing according to claim 7, characterized in that, The wall thickness of the second thickened section is 1.1 to 1.8 times that of the main body section; the wall thickness of the bottom section is 1.1 to 2 times that of the main body section.
9. The housing according to claim 7, characterized in that, The second step and the second thickened section form a second angle, which ranges from 90° to 110°.
10. A cylindrical battery, characterized in that, include: The housing as described in any one of claims 1 to 9; The core is disposed inside the housing and the core is wrapped with expansion tape; after the end is narrowed, the positive end of the expansion tape is limited by the first step of the housing; A cap is disposed at the positive end of the core, and the cap is fixedly connected to the opening section of the housing.