Battery cell shell and battery cell

Abstract

The invention relates to the technical field of energy storage equipment, in particular to a battery cell shell and a battery cell, and the battery cell shell comprises a shell body, an anti-explosion valve, a first cover plate assembly and a second cover plate assembly. The explosion-proof valve is arranged at the position, close to the second cover plate assembly, of the first side wall of the shell body, the first cover plate assembly covers an opening in one end of the shell body, and the first cover plate assembly comprises a positive electrode output terminal and a negative electrode output terminal. The second cover plate assembly covers the opening in the other end of the shell body and comprises a top cover plate and an insulating part, the insulating part is attached to the first end face, facing the inner cavity of the battery cell shell, of the top cover plate, a hot melting groove is formed in the first end face, a hot melting protruding part is arranged on the insulating part in a protruding mode, the hot melting protruding part forms a limiting end through hot melting, and the limiting end is located in the hot melting groove; and the cross sectional area of the limiting end is larger than the area of a notch of the hot melting groove. The battery cell comprises a pole group and the battery cell shell, wherein the pole group is arranged in the battery cell shell. The battery cell can be helpful for preventing thermal runaway from being intensified, and has higher safety performance.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage equipment, and in particular to a battery cell casing and a battery cell. Background Art

[0002] To ensure the safety of battery cells, the cell casing is typically equipped with a pressure relief mechanism, such as an explosion-proof valve. In the event of thermal runaway, the explosion-proof valve ruptures to release the high-temperature mixture, preventing explosion and minimizing damage. For thin, long-blade batteries, the casing typically has positive and negative output terminals at either end. The explosion-proof valve is typically located at one end, placing it very close to the output terminals. If the cell's temperature control components malfunction and the cell heats up, causing thermal runaway, the explosion-proof valve ruptures, rapidly discharging the high-temperature mixture. Furthermore, the proximity of the output terminals to the explosion-proof valve makes the insulation at the output terminals susceptible to melting and failure in the localized high temperature environment, resulting in a short circuit between the positive and negative terminals. This further exacerbates the severity of thermal runaway and can lead to safety accidents. Summary of the Invention

[0003] An object of the present invention is to provide a battery cell casing that can help prevent thermal runaway from worsening and improve the safety performance of the battery cell.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] Provided is a battery cell casing, comprising:

[0006] Shell body;

[0007] a first cover plate assembly, the first cover plate assembly being arranged to cover an opening at one end of the shell body, the first cover plate assembly comprising a positive output terminal and a negative output terminal;

[0008] a second cover plate assembly, the second cover plate assembly being arranged to cover the opening at the other end of the shell body, the second cover plate assembly comprising a top cover plate and an insulating member, the insulating member being attached to a first end surface of the top cover plate facing the inner cavity of the battery cell shell, a hot melt groove being provided on the first end surface, a hot melt protrusion being protruded on the insulating member, the hot melt protrusion being hot-melted to form a limiting end, the limiting end being located in the hot melt groove, and the cross-sectional area of the limiting end being larger than the area of the notch of the hot melt groove;

[0009] An explosion-proof valve is provided on the first side wall of the shell body near the second cover plate assembly.

[0010] Optionally, a limiting groove is provided in an annular manner on the side wall of the hot melt groove, and the edge of the limiting end is located in the limiting groove.

[0011] Optionally, along a direction perpendicular to the plane where the top cover plate is located, a height h1 of the limiting groove satisfies 0.2 mm ≤ h1 ≤ 1 mm.

[0012] Optionally, the limiting groove is located at the bottom of the hot melt groove, and along the direction perpendicular to the plane where the top cover plate is located, the depth h2 of the hot melt groove and the height h1 of the limiting groove meet the following condition: 0.4mm≤h2-h1≤2.5mm.

[0013] Optionally, the hot melt groove is a cylindrical groove, the depth direction of the cylindrical groove is its own axial direction, and the limiting groove is also a cylindrical structure, satisfying:

[0014] The radius a of the notch of the hot melt groove satisfies 2mm≤a≤4mm;

[0015] And / or, the radius b of the bottom of the limiting groove satisfies 2.5 mm ≤ a ≤ 4.5 mm;

[0016] And / or, the radius b of the bottom of the limiting groove and the radius a of the notch of the hot melt groove meet the following conditions: 0.5 mm ≤ ba ≤ 1 mm.

[0017] Optionally, the hot melt protrusion and the limiting end are both cylindrical structures, satisfying:

[0018] The radius c of the cross section of the hot melt protrusion satisfies 2mm≤c≤4mm;

[0019] And / or, the radius d of the cross section of the limiting end satisfies 2.5 mm ≤ d ≤ 4.5 mm;

[0020] And / or, the radius c of the cross section of the hot melt protrusion and the radius d of the cross section of the limiting end satisfy 0.5mm≤dc≤1mm.

[0021] Optionally, the height e of the hot-melt protrusion before hot-melt meets the requirement of 0.8 mm ≤ e ≤ 4 mm.

[0022] Optionally, the thickness f of the thickest part of the top cover plate satisfies 1mm≤f≤4mm;

[0023] And / or, the wall thickness g of the bottom of the hot melt tank satisfies the following condition: 0.5 mm ≤ g ≤ 3.5 mm;

[0024] And / or, along a direction perpendicular to the plane where the top cover plate is located, the thickness h of the thickest part of the insulating member where the hot melt protrusion is not provided satisfies the condition of 2mm≤h≤10mm.

[0025] Optionally, the difference between the volume of the hot melt protrusion and the volume of the cavity in the hot melt groove is in the range of -0.15mm 3-0.15mm 3 .

[0026] Another object of the present invention is to provide a battery cell that can help prevent thermal runaway from worsening and has higher safety performance.

[0027] To achieve this object, the present invention adopts the following technical solutions:

[0028] Provided is a battery cell, comprising a pole group and the above-mentioned battery cell shell, wherein the pole group is arranged in the battery cell shell.

[0029] Beneficial effects of the present invention:

[0030] The present invention provides a battery cell housing, comprising a housing, an explosion-proof valve, a first cover assembly, and a second cover assembly. The explosion-proof valve is positioned on a first sidewall of the housing near the second cover assembly. The first cover assembly covers an opening at one end of the housing. The first cover assembly includes a positive output terminal and a negative output terminal. The second cover assembly covers the other opening at the housing. The second cover assembly includes a top cover plate and an insulating member. The insulating member is attached to a first end surface of the top cover plate facing the inner cavity of the battery cell housing. The first end surface is provided with a heat-melting groove. The insulating member is provided with a heat-melting protrusion. The heat-melting protrusion is heat-melted to form a stopper. The stopper is located within the heat-melting groove, and the cross-sectional area of the stopper is larger than the area of the notch of the heat-melting groove. By positioning the explosion-proof valve on the first sidewall of the housing near the second cover assembly, the distance between the explosion-proof valve and the positive and negative output terminals can be increased. This helps prevent the insulation assembly at the output terminal from melting, which could cause a positive and negative short circuit during thermal runaway. This prevents thermal runaway from worsening and improves the safety performance of the battery cell.

[0031] The present invention also provides a battery cell comprising a pole group and the above-mentioned battery cell housing, wherein the pole group is disposed within the battery cell housing. The battery cell can help prevent thermal runaway from worsening and has higher safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the battery cell housing provided by an embodiment of the present invention;

[0033] Figure 2 This is a partial structural decomposition diagram of a battery cell provided by an embodiment of the present invention;

[0034] Figure 3 is a structural schematic diagram of a second cover plate assembly provided in an embodiment of the present invention;

[0035] Figure 4 is a schematic structural diagram of a top cover plate provided by an embodiment of the present invention;

[0036] Figure 5 is a schematic structural diagram of an insulating member provided by an embodiment of the present invention;

[0037] Figure 6 is a cross-sectional view of a top cover plate provided by an embodiment of the present invention;

[0038] Figure 7 is a cross-sectional view of an insulating member (before hot melting) provided by an embodiment of the present invention;

[0039] Figure 8 It is a cross-sectional view of the second cover plate assembly (after hot melting) provided in an embodiment of the present invention.

[0040] In the picture:

[0041] 1. Shell body; 11. First side wall; 2. Explosion-proof valve;

[0042] 3. First cover assembly; 31. Positive output terminal; 32. Negative output terminal;

[0043] 4. Second cover plate assembly; 41. Top cover plate; 411. Hot melt groove; 4111. Limiting groove; 42. Insulation member; 421. Hot melt protrusion; 4211. Limiting end; 422. Weight reduction groove;

[0044] 5. First patch; 6. Second patch; 7. External insulating film;

[0045] 100. Battery cell casing; 200. Electrode group; 300. Internal insulating film. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only show portions relevant to the present invention, not all of them.

[0047] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed or detachable connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention.

[0048] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0049] like Figures 1-8 As shown, the cell housing 100 of this embodiment includes a housing body 1, an explosion-proof valve 2, a first cover assembly 3, and a second cover assembly 4. The explosion-proof valve 2 is disposed on a first sidewall 11 of the housing body 1, and the first cover assembly 3 is disposed over an opening at one end of the housing body 1. The first cover assembly 3 includes a positive output terminal 31 and a negative output terminal 32. The second cover plate assembly 4 is covered at the opening at the other end of the shell body 1. The second cover plate assembly 4 includes a top cover plate 41 and an insulating member 42. The insulating member 42 is attached to the first end surface of the top cover plate 41 facing the inner cavity of the battery cell shell 100. A hot melt groove 411 is provided on the first end surface. A hot melt protrusion 421 is protruded on the insulating member 42. The hot melt protrusion 421 is hot-melted to form a limiting end 4211. The limiting end 4211 is located in the hot melt groove 411, and the cross-sectional area of the limiting end 4211 is larger than the area of the notch of the hot melt groove 411, which can ensure that the hot melt protrusion 421 cannot be separated from the hot melt groove 411 after hot melting, so as to realize the connection and fixation of the insulating member 42 and the top cover plate 41.

[0050] By setting the position of the explosion-proof valve 2 on the first side wall 11 of the shell body 1 close to the second cover assembly 4, the distance between the explosion-proof valve 2 and the positive and negative output terminals 32 can be increased, which can help prevent the positive and negative poles from being short-circuited due to the melting of the insulating components at the output terminals during thermal runaway, thereby preventing the thermal runaway from worsening and improving the safety performance of the battery cell.

[0051] Moreover, conventional cover plate assemblies are provided with poles, and generally the insulating part 42 is locked by fixing the poles to the top cover plate 41. However, the second cover plate assembly 4 in this case does not have poles, and the insulating part 42 is fixed to the top cover plate 41 by hot melt connection, which can ensure the connection strength between the insulating part 42 and the top cover plate 41, thereby preventing the insulating part 42 from being misplaced or deformed, resulting in insulation failure.

[0052] Optionally, a limiting groove 4111 is annularly opened on the side wall of the hot melt groove 411, and the edge of the limiting end 4211 is located in the limiting groove 4111, so that the limiting end 4211 can be limited by the side wall of the limiting groove 4111 away from the bottom of the hot melt groove 411.

[0053] Optionally, along the direction perpendicular to the plane where the top cover plate 41 is located, the height h1 of the limit groove 4111 satisfies the condition of 0.2mm≤h1≤1mm. When the height h1 of the limit groove 4111 is less than 0.2mm, the height of the limit groove 4111 will limit the thickness of the limit end 4211. When the thickness of the limit end 4211 is insufficient, the structural strength of the limit end 4211 is insufficient, and the limit end 4211 will easily detach from the limit groove 4111. In this case, the tensile and lateral thrust resistance of the insulating member 42 cannot be guaranteed, and the insulating member 42 may still be misaligned or even detach from the top cover plate 41 due to the force. Since the overall thickness of the top cover plate 41 cannot be too large, when the height h1 of the limit groove 4111 is greater than 1mm, either the height of the remaining positions of the hot melt groove 411 is too low, or the wall thickness of the bottom of the hot melt groove 411 is too small. If the rest of the hot melt groove 411 is too low, the base of the hot melt protrusion 421 will be too low after hot melting, which is not conducive to heating the hot melt protrusion 421 and inconvenient to operate. A slight deviation in the heating height can easily cause the insulating member 42 to deform due to hot melting in the area where the hot melt protrusion 421 is not provided. If the wall thickness of the bottom of the hot melt groove 411 is too small, the structural strength of the top cover plate 41 at the hot melt groove 411 will be affected, resulting in local weakness of the top cover plate 41, which is not conducive to ensuring the quality of the battery cell. Moreover, machining errors may also cause the hot melt groove 411 to penetrate, posing risks such as leakage, which is not conducive to improving the process yield of the battery cell.

[0054] Optionally, the limiting groove 4111 is located at the bottom of the hot melt groove 411. In a direction perpendicular to the plane of the top cover plate 41, the depth h2 of the hot melt groove 411 and the height h1 of the limiting groove 411 satisfy the following relationship: 0.4 mm ≤ h2 - h1 ≤ 2.5 mm. Optionally, the hot melt protrusion 421 after hot melting includes a connected root portion and a limiting end 4211. The root portion is located in the area of the hot melt groove 411 near the notch, and the limiting end 4211 is located within the limiting groove 4111. Therefore, the difference between the depth h2 of the hot melt groove 411 and the height h1 of the limiting groove 4111 limits the size of the root portion. If the difference between the depth h2 of the hot melt groove 411 and the height h1 of the limiting groove 4111 is less than 0.4 mm, if the root portion of the hot melt protrusion 421 is entirely within the hot melt groove 411, the root portion height is too small, which is not conducive to heating the hot melt protrusion 421 and inconvenient to operate. A slight deviation in the heating height can easily cause the insulating member 42 to deform due to hot melting in the area where the hot melt protrusion 421 is not provided. Alternatively, if the root portion of the hot melt protrusion 421 is mostly located outside the hot melt groove 411, the root portion is likely to bend and deform when the insulating member 42 is subjected to a lateral thrust, causing relative misalignment between the insulating member 42 and the top cover plate 41. However, if the difference between the depth h2 of the hot melt groove 411 and the height h1 of the limit groove 4111 is greater than 2.5 mm, then when the thickness of the top cover plate 41 is constant, the wall thickness of the bottom of the hot melt groove 411 will be too small, which will affect the structural strength of the top cover plate 41 at the hot melt groove 411, causing local weakness of the top cover plate 41, which is not conducive to ensuring the quality of the battery cell. In addition, processing errors may also cause the hot melt groove 411 to be through, posing risks such as leakage, which is not conducive to improving the process yield of the battery cell.

[0055] Optionally, the hot melt groove 411 is a cylindrical groove, the depth of which is in the axial direction, i.e., the cylindrical groove is deep along its own axial direction. The limiting groove 4111 is also a cylindrical structure. Accordingly, the hot melt protrusion 421 and the limiting end 4211 are also cylindrical structures. It can be seen that the cylindrical structure makes the material flow more uniform during the hot melt pressurization process, and the hot melt protrusion 421 is more likely to form a regular cylindrical limiting end 4211 with consistent edges, which is conducive to ensuring the fixing strength.

[0056] like Figure 6 As shown, the radius a of the hot melt groove 411 satisfies the condition 2mm≤a≤4mm. When the radius a of the hot melt groove 411 is less than 2mm, the hot melt groove 411 is too narrow, which will limit the size of the hot melt protrusion 421. When the cross-section of the hot melt protrusion 421 is too small, the structural strength of the hot melt protrusion 421 is insufficient, and the hot melt protrusion 421 is easily broken when the insulating member 42 is subjected to force, the connection function of the hot melt structure fails, and the insulating member 42 is separated from the top cover plate 41. When the radius a of the hot melt groove 411 is greater than 4mm, the hot melt groove 411 is too wide, the structural strength of the top cover plate 41 at the hot melt groove 411 is insufficient, and the performance of the battery cell in resisting external forces is reduced.

[0057] Optionally, the radius b of the bottom of the limiting groove 4111 satisfies the condition of 2.5 mm ≤ a ≤ 4.5 mm. When the radius b of the bottom of the limiting groove 4111 is less than 2.5 mm, the limiting groove 4111 is too narrow, which will limit the size of the limiting end 4211. If the cross-section of the limiting end 4211 is too small, either the hanging area is too narrow, and the insulating member 42 and the top cover plate 41 will not be firmly fixed, or the hot melt protrusion 421 is too thin as a whole and the structural strength is insufficient, which makes it easy for the hot melt protrusion 421 to break when the insulating member 42 is subjected to force, and the connection function of the hot melt structure fails, causing the insulating member 42 to separate from the top cover plate 41. When the radius b of the bottom of the limiting groove 4111 is greater than 4.5 mm, the limiting groove 4111 is too wide, which will either cause the cross-section of the limiting end 4211 in the design to be much larger than the cross-section of the root, resulting in insufficient hot melt flow, and the limiting end 4211 cannot fill the limiting groove 4111. The contact area between the limiting end 4211 and the limiting groove 4111 is limited, which will still cause the insulating part 42 to easily separate from the top cover plate 41. Or the limiting end 4211 and the root are both thicker, resulting in the need to increase the radius of the hot melt groove 411 accordingly, then the structural strength of the top cover plate 41 at the hot melt groove 411 is insufficient, and the performance of the battery cell in resisting external forces is reduced.

[0058] Optionally, the radius b of the bottom of the limiting groove 4111 and the radius a of the notch of the hot melt groove 411 meet the following conditions: 0.5mm≤ba≤1mm. When the difference between the radius b of the bottom of the limiting groove 4111 and the radius a of the notch of the hot melt groove 411 is less than 0.5mm, the size of the hanging platform of the hot melt protrusion 421 will be limited. If the size of the hanging platform is too small, the connection strength between the insulating part 42 and the top cover plate 41 will be insufficient. When the difference between the radius b of the bottom of the limiting groove 4111 and the radius a of the notch of the hot melt groove 411 is greater than 1mm, the material of the hot melt protrusion 421 is not easy to fill the limiting groove 4111 during the hot melt pressure process, which easily causes a gap between the side wall of the limiting end 4211 and the side wall of the limiting groove 4111. The shape of the limiting end 4211 is irregular, resulting in the problem of insufficient local hanging platform.

[0059] It should be noted that the hot melt protrusion 421 is actually in the shape of a cone, which facilitates injection molding and demolding of the insulating part 42. However, due to the extremely small inclination angle, this case is explained as if the hot melt protrusion 421 is in a cylindrical shape, so the concept of the radius of the cross section of the hot melt protrusion 421 is directly proposed.

[0060] like Figure 7As shown, optionally, the radius c of the cross section of the hot melt protrusion 421 satisfies 2mm≤c≤4mm. When the radius c of the cross section of the hot melt protrusion 421 is less than 2mm, the cross section of the hot melt protrusion 421 is too small, the structural strength of the hot melt protrusion 421 is insufficient, and the hot melt protrusion 421 is prone to breakage when the insulating member 42 is subjected to force, the connection function of the hot melt structure fails, and the insulating member 42 is separated from the top cover plate 41. When the radius c of the cross section of the hot melt protrusion 421 is greater than 4mm, the hot melt groove 411 also needs to be set wider accordingly, which will affect the structural strength of the top cover plate 41 at the hot melt groove 411, and the performance of the battery cell in resisting external forces will be reduced.

[0061] Optionally, the radius d of the cross section of the limiting end 4211 satisfies 2.5mm≤d≤4.5mm. When the radius d of the cross section of the limiting end 4211 is less than 2.5mm, the cross section of the limiting end 4211 is too small, or the hanging platform area is too narrow, the insulating part 42 and the top cover plate 41 will not be firmly connected, or the root of the hot melt protrusion 421 is too thin and the structural strength is insufficient, and it is easy for the root of the hot melt protrusion 421 to break when the insulating part 42 is subjected to force, the connection function of the hot melt structure fails, and the insulating part 42 is separated from the top cover plate 41. When the radius d of the cross section of the limiting end 4211 is greater than 4.5mm, either the hanging platform size is too large, the hot melt extrusion is difficult, and the regularity of the limiting end 4211 is not easy to ensure, or the limiting end 4211 and the root are both thick, so that the radius of the hot melt groove 411 needs to be increased accordingly, then the structural strength of the top cover plate 41 at the hot melt groove 411 is insufficient, and the performance of the battery cell in resisting external forces is reduced.

[0062] Optionally, the radius c of the cross section of the hot melt protrusion 421 and the radius d of the cross section of the limiting end 4211 satisfy 0.5mm≤dc≤1mm. When the difference between the radius d of the cross section of the limiting end 4211 and the radius c of the cross section of the hot melt protrusion 421 is less than 0.5mm, the size of the hanging platform is too small, and the connection strength between the insulating member 42 and the top cover plate 41 is insufficient. When the difference between the radius d of the cross section of the limiting end 4211 and the radius c of the cross section of the hot melt protrusion 421 is greater than 1mm, it is difficult for the material to fill the limiting groove 4111 during the hot melt pressure process of the hot melt protrusion 421, which easily causes a gap between the side wall of the limiting end 4211 and the side wall of the limiting groove 4111, and the shape of the limiting end 4211 is irregular, resulting in the problem of insufficient local hanging platform.

[0063] like Figure 7As shown, optionally, the height e of the hot-melt protrusion 421 before hot-melt meets the requirement of 0.8mm≤e≤4mm. When the height e of the hot-melt protrusion 421 before hot-melt is less than 0.8mm, the height of the root and the limit end 4211 will be limited. A too small root height is not conducive to heating the hot-melt protrusion 421, making operation inconvenient. A slight deviation in the heating height can easily cause the area around the hot-melt protrusion 421 on the insulating member 42 to be hot-melted and deformed. When the height e of the hot-melt protrusion 421 before hot-melt is greater than 4mm, if the root of the hot-melt protrusion 421 is located within the hot-melt groove 411, the hot-melt groove 411 is too deep, and the structural strength of the hot-melt groove 411 on the top cover plate 41 is too low, which is not conducive to ensuring the performance of the battery cell in resisting external forces. If the root of the hot-melt protrusion 421 is mostly located outside the hot-melt groove 411 , the root is easily bent and deformed when the insulating member 42 is subjected to a lateral thrust, causing relative misalignment between the insulating member 42 and the top cover plate 41 .

[0064] like Figure 6 As shown, optionally, the thickness f at the thickest point of the top cover plate 41 satisfies 1mm≤f≤4mm. If the thickness f at the thickest point of the top cover plate 41 is less than 1mm, the structural strength of the top cover plate 41 will be insufficient, which is not conducive to ensuring the battery cell's ability to resist external forces. If the thickness f at the thickest point of the top cover plate 41 exceeds 4mm, the top cover plate 41 is too thick and takes up too much space, which is not conducive to improving the energy density of the battery cell.

[0065] Optionally, in this embodiment, the top cover plate 41 is a plain aluminum sheet. Of course, in other embodiments, the top cover plate 41 can also be configured as a plate-like structure made of other materials.

[0066] like Figure 6 As shown, optionally, the wall thickness g of the bottom of the hot melt groove 411 satisfies 0.5mm≤g≤3.5mm. If the wall thickness g of the bottom of the hot melt groove 411 is less than 0.5mm, the structural strength of the top cover plate 41 where the hot melt groove 411 is provided will be insufficient, which is not conducive to ensuring the local resistance of the battery cell to external forces. If the wall thickness g of the bottom of the hot melt groove 411 exceeds 3.5mm, if the thickness f of the thickest part of the top cover plate 41 remains unchanged, the hot melt groove 411 is too shallow and the hot melt connection strength is insufficient.

[0067] like Figure 7 As shown, optionally, along a direction perpendicular to the plane of the top cover plate 41, the thickness h of the thickest portion of the insulating member 42, where the hot melt protrusion 421 is not provided, satisfies the condition 2 mm ≤ h ≤ 10 mm. If the thickness h of the thickest portion of the insulating member 42, where the hot melt protrusion 421 is not provided, is less than 2 mm, the structural strength of the insulating member 42 is too low, and a large external force can easily penetrate the insulating member 42, causing insulation failure. If the thickness h of the thickest portion of the insulating member 42, where the hot melt protrusion 421 is not provided, exceeds 10 mm, it takes up too much space, which is not conducive to improving the energy density of the battery cell.

[0068] Optionally, in this embodiment, the insulating member 42 is made of plastic to facilitate processing and hot melting to form the limiting end 4211 .

[0069] Optionally, the hot melt protrusions 421 are all located in the hot melt groove 411 to prevent the hot melt protrusions 421 that are not in the hot melt groove 411 from bending and deforming. Optionally, the size of the base of the hot melt protrusions 421 is adapted to the size of the notch of the hot melt groove 411 so that the base of the hot melt protrusions 421 is just located in the hot melt groove 411.

[0070] Optionally, the difference between the volume of the hot melt protrusion 421 and the volume of the cavity in the hot melt groove 411 is in the range of -0.15mm 3 -0.15mm 3 When the difference between the volume of the hot melt protrusion 421 and the volume of the cavity in the hot melt groove 411 is less than -0.15mm 3 When the limit end 4211 cannot fill the limit groove 4111, there is a gap between the two, which easily leads to irregular structure of the limit end 4211, uneven size along the circumference, and the problem of insufficient local hanging platform. When the insulating part 42 is impacted by external force, it may cause the insulating part 42 to partially separate from the top cover plate 41 and rise. When the difference between the volume of the hot melt protrusion 421 and the volume of the cavity in the hot melt groove 411 is greater than 0.15mm 3 When hot-melting, there is too much excess material, which can easily cause part of the hot-melt protrusion 421 to be squeezed out of the hot-melt groove 411, causing the root to be easily bent and deformed, and the insulating part 42 cannot be well attached to the top cover plate 41. If the insulating part 42 is squeezed by the electrode group 200, the reverse side of the hot-melt protrusion 421 will bulge, and the insulating part 42 will be uneven, which will affect the yield of the battery cell.

[0071] In order to verify that the above-mentioned battery cell housing 100 can solve the problem of thermal runaway escalation caused by the close proximity of thermoelectric elements, and when meeting the above-mentioned more optimal size conditions, it can ensure the connection strength between the insulating member 42 and the top cover plate 41, the flatness of the insulating member 42, etc., thereby improving the process yield and safety performance of the battery cell, as shown in Table 1 below, this embodiment provides ten groups of examples and six groups of comparative examples of battery cells, and after the top cover plate 41 and the insulating member 42 of the second cover plate assembly 4 of the battery cell housing 100 of the battery cell are hot-melt pressed, the connection strength between the top cover plate 41 and the insulating member 42, whether the insulating member 42 is deformed, and whether the top cover plate 41 and the insulating member 42 are aligned are tested. After the overall assembly of the battery cell is completed, the battery cell is subjected to an abnormally heated thermal runaway test to detect whether there is a phenomenon of thermal runaway escalation.

[0072] Among them, the similarities between the battery cell casings 100 of the ten groups of examples and the eight groups of comparative examples are that: the hot melt groove 411 is a cylindrical structure where the limiting groove 4111 is not provided, and the limiting groove 4111 is also a cylindrical structure. Correspondingly, the hot melt protrusion 421 and the limiting end 4211 are also cylindrical structures, and the height h1 of the limiting groove 4111 satisfies 0.2mm≤h1≤1mm, the depth h2 of the hot melt groove 411 and the height h1 of the limiting groove 4111 satisfy 0.4mm≤h2-h1≤2.5mm, the radius a of the notch of the hot melt groove 411 satisfies 2mm≤a≤4mm, the radius b of the bottom of the limiting groove 4111 satisfies 2.5mm≤a≤4.5mm, and the radius b of the bottom of the limiting groove 4111 and the radius a of the notch of the hot melt groove 411 satisfy 0 .5mm≤ba≤1mm, the radius c of the cross section of the hot melt protrusion 421 satisfies 2mm≤c≤4mm, the height e of the hot melt protrusion 421 before hot melting satisfies 0.8mm≤e≤4mm, the thickness f of the thickest part of the top cover plate 41 satisfies 1mm≤f≤4mm, the wall thickness g of the bottom of the hot melt groove 411 satisfies 0.5mm≤g≤3.5mm, the thickness h of the thickest part of the insulating part 42 where the hot melt protrusion 421 is not set satisfies 2mm≤h≤10mm, and the size of the root of the hot melt protrusion 421 is adapted to the size of the notch of the hot melt groove 411, so that the root of the hot melt protrusion 421 is just located in the hot melt groove 411, and it can be considered that the radius a of the notch of the hot melt groove 411 is basically consistent with the radius c of the cross section of the hot melt protrusion 421.

[0073] Table 1

[0074]

[0075]

[0076] Specifically, Table 1 above shows the various dimensional parameters of the battery cell housing 100 of ten groups of battery cells of the example. The dimensional parameters all meet the above-mentioned restriction conditions, that is, the difference between the volume of the hot melt protrusion 421 and the volume of the cavity in the hot melt groove 411 is within -0.15mm. 3 -0.15mm 3 range. The connection strength between the top cover plate 41 and the insulating part 42 of the battery cell housing 100 of the ten groups of examples meets the technical requirements, the insulating part 42 is not deformed, the top cover plate 41 and the insulating part 42 can also be aligned, and the process yield of the battery cells of these ten groups of examples is relatively high. After the overall assembly of the battery cell is completed, the battery cell is subjected to a thermal runaway test with abnormal temperature increase, and no thermal runaway escalation phenomenon occurs. It can be seen that setting the explosion-proof valve 2 on the first side wall 11 of the shell body 1 close to the second cover plate assembly 4 and increasing the distance between the explosion-proof valve 2 and the positive and negative output terminals 32 can indeed prevent the insulating assembly at the output terminal from melting during thermal runaway, resulting in a short circuit between the positive and negative poles, and can effectively prevent the thermal runaway from worsening.

[0077] As shown in Table 1 above, the difference between the volume of the hot melt protrusion 421 and the volume of the cavity in the hot melt groove 411 of the battery cells of Comparative Examples 1 to 3 is greater than the maximum value of the optimal value range, that is, 0.15mm 3 Testing revealed excessive material in the hot-melt protrusions 421 of this group of cells. This caused overflow during hot-melt press-fitting, resulting in an uneven bottom and warping of the insulating member 42. The manufacturing yields for all three groups of cells were low. However, after the cells were fully assembled, no thermal runaway escalation was observed during abnormal temperature rise thermal runaway testing.

[0078] As shown in Table 1 above, the difference between the volume of the hot melt protrusion 421 and the volume of the cavity in the hot melt groove 411 of the battery cells of Comparative Examples 4 to 6 is less than the minimum value of the optimal value range, that is, -0.15mm 3 . Upon inspection, it was found that the hot-melt protrusion 421 of this group of battery cells had too little material, and the material could not be fully filled in the limiting groove 4111 during hot-melt pressing, resulting in an irregular structure of the limiting end 4211, and the contact area between the limiting end 4211 and the limiting groove 4111 was too small. The limiting end 4211 easily separated from the limiting groove 4111, resulting in insufficient connection strength between the insulating member 42 and the top cover plate 41, and the insulating member 42 easily fell off under stress. The process yield of these three groups of battery cells was low, and the process yield of Comparative Examples 6, 5, and 4 gradually increased. It can be seen that the closer the difference between the volume of the hot-melt protrusion 421 and the volume of the cavity in the hot-melt groove 411 is to the more optimal value range, the higher the process yield of the battery cell. However, after the overall assembly of the battery cell was completed, no thermal runaway escalation phenomenon occurred in the abnormal temperature rise thermal runaway test of the battery cell.

[0079] It can be seen that when the following conditions are met: the hot melt groove 411 is cylindrical in structure where the limiting groove 4111 is not provided, the limiting groove 4111 is also cylindrical in structure, and accordingly, the hot melt protrusion 421 and the limiting end 4211 are also cylindrical in structure, the height h1 of the limiting groove 4111 satisfies 0.2mm≤h1≤1mm, the depth h2 of the hot melt groove 411 and the height h1 of the limiting groove 4111 satisfy 0.4mm≤h2-h1≤2.5mm, the radius a of the notch of the hot melt groove 411 satisfies 2mm≤a≤4mm, the radius b of the bottom of the limiting groove 4111 satisfies 2.5mm≤a≤4.5mm, and the radius of the bottom of the limiting groove 4111 satisfies b and the radius a of the notch of the hot melt groove 411 satisfy 0.5mm≤ba≤1mm, the radius c of the cross section of the hot melt protrusion 421 satisfies 2mm≤c≤4mm, the height e of the hot melt protrusion 421 before hot melting satisfies 0.8mm≤e≤4mm, the thickness f of the thickest part of the top cover plate 41 satisfies 1mm≤f≤4mm, the wall thickness g of the groove bottom of the hot melt groove 411 satisfies 0.5mm≤g≤3.5mm, the thickness h of the thickest part of the insulating part 42 where the hot melt protrusion 421 is not provided satisfies 2mm≤h≤10mm, and the difference between the volume of the hot melt protrusion 421 and the volume of the cavity in the groove of the hot melt groove 411 is both within -0.15mm 3 -0.15mm 3 Within this range, it is possible to ensure that there is no risk of insulation failure at the second cover plate assembly 4 while ensuring thermal and electrical separation and no thermal runaway escalation, and to ensure that the top cover plate 41 and the insulating member 42 are firmly connected, and that the relative positions of the two are in line with the product design, and the process yield of the battery cell is high.

[0080] Optionally, the battery cell casing 100 also includes a first patch 5, a second patch 6 and an outer insulating film 7. The first patch 5 is attached to the outside of the first cover assembly 3 to ensure that the first cover assembly 3 is not conductive to the outside world. The second patch 6 is attached to the outside of the second cover assembly 4 to ensure that the second cover assembly 4 is not conductive to the outside world. The outer insulating film 7 is wrapped around the outside of the shell body 1 to ensure that the shell body 1 is not conductive to the outside world.

[0081] This embodiment further provides a battery cell, comprising an electrode group 200 and the aforementioned battery cell housing 100, wherein the electrode group 200 is disposed within the battery cell housing 100. Optionally, the battery cell further comprises an inner insulating film 300, which is wrapped around the electrode group 200 to ensure insulation between the electrode group 200 and the housing body 1.

[0082] This battery cell can help prevent the thermal runaway from worsening, has higher safety performance, and can ensure that there is no risk of insulation failure at the second cover plate assembly 4. The top cover plate 41 and the insulating part 42 are firmly connected, and the relative position between the two is also in line with the product design. The process yield of the battery cell is high.

[0083] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A battery cell casing, characterized in that: include: Shell body (1); a first cover plate assembly (3), the first cover plate assembly (3) being arranged to cover an opening at one end of the shell body (1), the first cover plate assembly (3) comprising a positive output terminal (31) and a negative output terminal (32); a second cover plate assembly (4), the second cover plate assembly (4) being arranged to cover the other end opening of the shell body (1), the second cover plate assembly (4) comprising a top cover plate (41) and an insulating member (42), the insulating member (42) being attached to a first end surface of the top cover plate (41) facing the inner cavity of the battery cell shell (100), a hot melt groove (411) being provided on the first end surface, a hot melt protrusion (421) being protruded from the insulating member (42), the hot melt protrusion (421) being hot-melted to form a limiting end (4211), the limiting end (4211) being located in the hot melt groove (411), and the cross-sectional area of the limiting end (4211) being larger than the area of the notch of the hot melt groove (411); An explosion-proof valve (2) is provided on the first side wall (11) of the shell body (1) near the second cover plate assembly (4).

2. The battery cell casing according to claim 1, wherein: A limiting groove (4111) is provided in an annular manner on the side wall of the hot melt groove (411), and the edge of the limiting end (4211) is located in the limiting groove (4111).

3. The battery cell casing according to claim 2, wherein: Along a direction perpendicular to the plane where the top cover plate (41) is located, the height h1 of the limiting groove (4111) satisfies 0.2mm≤h1≤1mm.

4. The battery cell casing according to claim 2, wherein: The limiting groove (4111) is located at the bottom of the hot melt groove (411), and along the direction perpendicular to the plane where the top cover plate (41) is located, the depth h2 of the hot melt groove (411) and the height h1 of the limiting groove (4111) meet the following conditions: 0.4mm≤h2-h1≤2.5mm.

5. The battery cell casing according to claim 2, characterized in that: The hot melt groove (411) is a cylindrical groove, the depth direction of the cylindrical groove is its own axial direction, and the limiting groove (4111) is also a cylindrical structure, satisfying: The radius a of the notch of the hot melt groove (411) satisfies 2mm≤a≤4mm; And / or, the radius b of the bottom of the limiting groove (4111) satisfies 2.5 mm ≤ a ≤ 4.5 mm; And / or, the radius b of the bottom of the limiting groove (4111) and the radius a of the slot opening of the hot melt groove (411) satisfy 0.5mm≤ba≤1mm.

6. The battery cell casing according to claim 1, characterized in that: The hot-melt protrusion (421) and the limiting end (4211) are both cylindrical structures, satisfying: The radius c of the cross section of the hot melt protrusion (421) satisfies 2mm≤c≤4mm; And / or, the radius d of the cross section of the limiting end (4211) satisfies 2.5 mm ≤ d ≤ 4.5 mm; And / or, the radius c of the cross section of the hot melt protrusion (421) and the radius d of the cross section of the limiting end (4211) satisfy 0.5mm≤dc≤1mm.

7. The battery cell casing according to claim 1, wherein: The height e of the hot-melt protrusion (421) before hot-melt meets the following condition: 0.8 mm ≤ e ≤ 4 mm.

8. The battery cell casing according to claim 1, wherein: The thickness f of the thickest part of the top cover plate (41) satisfies 1mm≤f≤4mm; And / or, the wall thickness g of the bottom of the hot melt groove (411) satisfies 0.5 mm ≤ g ≤ 3.5 mm; And / or, along a direction perpendicular to the plane where the top cover plate (41) is located, the thickness h of the thickest part of the insulating member (42) where the hot melt protrusion (421) is not provided satisfies 2mm≤h≤10mm.

9. The battery cell casing according to claim 1, wherein: The difference between the volume of the hot melt protrusion (421) and the volume of the cavity in the hot melt groove (411) is in the range of -0.15mm. 3 -0.15mm 3 .

10. A battery cell, characterized in that: The invention comprises a pole group (200) and a battery cell casing according to any one of claims 1 to 9, wherein the pole group (200) is arranged in the battery cell casing (100).

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