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. A first opening and a second opening are formed in the two ends, in the length direction of the shell body, of the shell body respectively, and one end, in the width direction of the shell body, of the shell body is a first side wall. The first cover plate assembly covers the first opening. The first cover plate assembly comprises a positive electrode output terminal and a negative electrode output terminal. The second cover plate assembly covers the second opening and comprises a top cover and lower plastic, a riveting column is arranged on the end face, facing the inner cavity of the battery cell shell, of the top cover, a riveting hole is formed in the lower plastic in a penetrating mode, and the riveting column and the riveting hole are fixed in a riveting mode. The anti-explosion valve is arranged on the wall surface, except the first cover plate assembly, of the battery cell shell. 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 shell of the battery cell is helpful for preventing thermal runaway upgrading, and has higher safety.

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] The battery cell casing is typically equipped with a pressure relief mechanism, such as an explosion-proof valve. In the event of thermal runaway, the high-temperature mixture is discharged from the pressure relief mechanism at a specific point, preventing the cell from exploding. For thinner, long-blade batteries, positive and negative output terminals are typically located at either end of the cell casing. The explosion-proof valve is typically located at one end, meaning it is very close to the output terminals. When a cell's temperature control components malfunction, causing thermal runaway, the explosion-proof valve opens as the temperature and pressure inside the cell rise, rapidly discharging the high-temperature mixture. Furthermore, because the output terminals are located so close to the explosion-proof valve, the insulation components at the output terminals can easily melt and fail in high-temperature environments, causing a short circuit between the positive and negative electrodes. 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 escalation and improve the safety 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] A shell body, wherein the shell body has a first opening and a second opening at both ends along its length direction, and one end of the shell body along its width direction is a first side wall;

[0007] a first cover plate assembly, the first cover plate assembly being arranged to cover the first opening, the first cover plate assembly comprising a positive output terminal and a negative output terminal;

[0008] a second cover assembly, the second cover assembly being arranged to cover the second opening, the second cover assembly comprising a top cover and a lower plastic member, the top cover having a rivet post on an end surface facing the inner cavity of the battery cell housing, the lower plastic member having a rivet hole extending therethrough, the rivet post being fixed to the rivet hole by riveting;

[0009] An explosion-proof valve is provided on the wall surface of the battery cell housing except the first cover assembly.

[0010] Optionally, the explosion-proof valve is arranged on the first side wall and close to the second opening.

[0011] Optionally, a weight-reducing groove is provided on the end surface of the lower plastic facing the inner cavity of the battery cell housing, and the rivet hole is provided at the bottom of the weight-reducing groove.

[0012] Optionally, a reinforcing rib is provided on the bottom of the weight-reducing groove, and the reinforcing rib divides the weight-reducing groove into a plurality of sub-grooves.

[0013] Optionally, at least one rivet hole is provided at the bottom of each sub-slot.

[0014] Optionally, before riveting, the height h1 of the riveted column is greater than the thickness t1 of the bottom of the weight-reducing groove;

[0015] And / or, after riveting, the overall height h2 of the riveted column is less than the maximum thickness H1 of the lower plastic.

[0016] Optionally, before riveting, the height h1 of the riveting column is less than the maximum thickness H1 of the lower plastic.

[0017] Optionally, the cross section of the riveted column before riveting is circular, the cross section of the riveted hole is also circular, and the difference between the diameter of the riveted hole and the cross section of the riveted column before riveting is in the range of 0.1 mm to 0.5 mm.

[0018] Optionally, the thickness a of the top cover where the riveted column is not provided satisfies 1 mm ≤ a ≤ 4 mm;

[0019] And / or, the maximum thickness H1 of the lower plastic satisfies 1.5 mm ≤ H1 ≤ 4 mm.

[0020] Another object of the present invention is to provide a battery cell whose battery cell casing helps prevent thermal runaway escalation and has higher safety.

[0021] To achieve this object, the present invention adopts the following technical solutions:

[0022] Provided is a battery cell, comprising a pole group and the above-mentioned battery cell shell, wherein the pole group is arranged inside the battery cell shell.

[0023] Beneficial effects of the present invention:

[0024] The present invention provides a battery cell casing, comprising a casing body, an explosion-proof valve, a first cover plate assembly, and a second cover plate assembly. The casing body is provided with a first opening and a second opening at both ends along its length, and one end of the casing body along its width is a first side wall. The first cover plate assembly is provided to cover the first opening, and the first cover plate assembly includes a positive output terminal and a negative output terminal. The second cover plate assembly is provided to cover the second opening, and the second cover plate assembly includes a top cover and a lower plastic. The top cover has a rivet post on the end face facing the inner cavity of the battery cell casing, and the lower plastic is provided with a rivet hole, and the rivet post is fixed to the rivet hole by riveting. The explosion-proof valve is provided on the wall surface of the battery cell casing other than the first cover plate assembly. By providing the positive output terminal and the negative output terminal at one end of the battery cell casing and providing the explosion-proof valve on the other wall surface, the thermoelectric distance can be increased, which helps prevent the output terminal from being affected by a high-temperature mixture mixed with sparks during thermal runaway, and prevents the positive and negative short circuits from being aggravated due to the failure of the insulating parts at the output terminals, thereby preventing the thermal runaway from escalating. Therefore, the battery cell casing can help prevent the escalation of thermal runaway and improve the safety of the battery cell.

[0025] 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 inside the battery cell housing. The battery cell housing of the battery cell helps prevent thermal runaway escalation and has higher safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of a portion of the structure of a battery cell housing provided by an embodiment of the present invention;

[0027] Figure 2 is an exploded schematic diagram of a battery cell provided by an embodiment of the present invention;

[0028] Figure 3 is a structural schematic diagram of a second cover plate assembly provided in an embodiment of the present invention;

[0029] Figure 4 is a schematic structural diagram of a top cover provided by an embodiment of the present invention;

[0030] Figure 5 Schematic diagram of the structure of the lower plastic provided by an embodiment of the present invention;

[0031] Figure 6 is a cross-sectional view of the second cover plate assembly (before riveting) provided by an embodiment of the present invention;

[0032] Figure 7 It is a cross-sectional view of the second cover plate assembly (after riveting) provided in an embodiment of the present invention.

[0033] In the picture:

[0034] 1. Shell body; 11. First side wall;

[0035] 2. Explosion-proof valve;

[0036] 3. First cover plate assembly; 31. Positive output terminal; 32. Negative output terminal;

[0037] 4. Second cover assembly; 41. Top cover; 411. Riveted column; 42. Lower plastic; 421. Riveted hole; 422. Reinforcement rib; 423. Slot;

[0038] 5. First patch; 6. Second patch; 7. External insulating film;

[0039] 100. Battery cell casing; 200. Electrode group; 300. Internal insulating film. DETAILED DESCRIPTION

[0040] Before any embodiments of the present application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the foregoing drawings.

[0041] In this application, the terms "comprises," "includes," "has," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0042] In this application, the term "and / or" describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Additionally, the character " / " in this application generally indicates that the related objects are in an "and / or" relationship.

[0043] In this application, the terms "connect," "combine," "couple," and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without an intermediary, and an indirect connection refers to two parts or components being connected to at least one intermediary, with the two parts or components being connected via the intermediary. Furthermore, "connect" and "couple" are not limited to physical or mechanical connections or couplings and may include electrical connections or couplings.

[0044] In this application, it will be understood by those skilled in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerance caused by manufacturing, assembly, use, etc. associated with a specific value. Such terms should also be considered to disclose a range defined by the absolute values of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values that do not use relative terms should also be disclosed as specific values with tolerances. In addition, "substantially" may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) on the basis of the indicated angle when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular).

[0045] In this application, it will be understood by those skilled in the art that the function performed by an assembly can be performed by one assembly, multiple assemblies, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one assembly, or a combination of multiple parts.

[0046] In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to the other element "upper" or "lower", but also be indirectly connected to the other element "upper" or "lower" through an intermediate element. It should also be understood that directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, below can include directly below, lower left, lower right, lower front and lower back, etc.

[0047] The battery cell casing is typically equipped with a pressure relief mechanism, such as an explosion-proof valve. In the event of thermal runaway, the high-temperature mixture is discharged from the pressure relief mechanism at a specific point, preventing explosion. For thinner, long-blade batteries, positive and negative output terminals are typically located at either end of the casing. The explosion-proof valve is typically located at one end, meaning it is very close to the output terminals. When a cell's temperature control components malfunction, causing thermal runaway, the explosion-proof valve opens as the internal temperature and pressure rise, rapidly discharging the high-temperature mixture. Furthermore, because the output terminals are located so close to the explosion-proof valve, the insulation components of the output terminals can easily melt and fail in high-temperature environments, causing a short circuit between the positive and negative electrodes. This further exacerbates the severity of thermal runaway and can lead to safety accidents.

[0048] Therefore, this embodiment provides a battery cell casing 100 to solve the above problems. The battery cell casing 100 can help prevent the escalation of thermal runaway and improve the safety of the battery cell.

[0049] like Figure 1-Figure 7 As shown, the battery 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 housing body 1 is provided with a first opening and a second opening at both ends along its length direction, and one end of the housing body 1 along its width direction is a first side wall 11. The explosion-proof valve 2 is provided on the wall surface of the battery cell housing 100 other than the first cover assembly 3, that is, it can be provided on the second cover assembly 4, or on a side wall of the housing body 1. Optionally, the explosion-proof valve 2 is provided on the first side wall 11 and is provided close to the second opening. The first cover assembly 3 is provided to cover the first opening, and the first cover assembly 3 includes a positive output terminal 31 and a negative output terminal 32. The second cover assembly 4 is covered at the second opening. The second cover assembly 4 includes a top cover 41 and a lower plastic 42. The top cover 41 has a rivet column 411 on the end surface facing the inner cavity of the battery cell housing 100. The lower plastic 42 has a rivet hole 421 extending therethrough. The rivet column 411 is fixed to the rivet hole 421 by riveting.

[0050] By arranging the positive and negative output terminals 31 and 32 at one end of the cell housing 100 and disposing the explosion-proof valve 2 on the first sidewall 11, away from the positive and negative output terminals 31 and 32, the thermal and electrical distance can be increased, helping to prevent the output terminals from being affected by a high-temperature mixture containing sparks during thermal runaway. This can also prevent the failure of the insulation at the output terminals from exacerbating the positive and negative short circuits and escalating thermal runaway. Therefore, the cell housing 100 can help prevent the escalation of thermal runaway and improve the safety of the battery cell.

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

[0052] like Figure 3 and Figure 5 As shown, optionally, in order to reduce the weight of the lower plastic 42, a weight-reducing groove is provided on the end surface of the lower plastic 42 facing the inner cavity of the battery cell housing 100, and the rivet hole 421 is provided at the bottom of the weight-reducing groove. The portion of the rivet column 411 protruding from the rivet hole 421 can be accommodated in the weight-reducing groove, which helps to prevent the rivet column 411 from being conductive with the electrode group 200, thereby preventing the battery cell from short-circuiting.

[0053] Optionally, a reinforcing rib 422 is provided at the bottom of the weight-reducing groove, dividing the groove into a plurality of sub-grooves 423. The reinforcing rib 422 not only improves the structural strength of the lower plastic 42 and prevents deformation of the lower plastic 42, but also prevents the electrode assembly 200 from contacting the bottom of the weight-reducing groove, thereby preventing contact and conduction between the electrode assembly 200 and the rivet post 411.

[0054] Optionally, in this embodiment, two reinforcing ribs 422 are arranged crosswise, with the intersection located at the center of the lower plastic 42, to ensure more balanced structural strength across the lower plastic 42. In other embodiments, one, three, four, or more reinforcing ribs 422 may be provided. Multiple reinforcing ribs 422 may be arranged parallel to each other, intersecting perpendicularly, or partially parallel and partially intersecting perpendicularly. This arrangement can be adjusted based on the size and shape of the lower plastic 42.

[0055] Optionally, each sub-slot 423 has at least one rivet hole 421 at its bottom, ensuring a more even distribution of the rivet holes 421. Optionally, in this embodiment, each of the four sub-slots 423 has a rivet hole 421 at its bottom, for a total of four rivet holes 421. Accordingly, the top cover 41 has four rivet posts 411. In other embodiments, the number of rivet posts 411 and rivet holes 421 can be one, two, three, five, six, or more, depending on the size and shape of the lower plastic 42 and the size of the rivet posts 411.

[0056] like Figure 6 As shown, optionally, the height h1 of the rivet column 411 before riveting is greater than the thickness t1 of the bottom of the weight-reducing groove, that is, the rivet column 411 can pass through the rivet hole 421, and the end of the rivet column 411 is located above the bottom of the weight-reducing groove, which can facilitate riveting the rivet column 411 and ensure that the top cover 41 and the lower plastic 42 are firmly riveted.

[0057] like Figure 7 As shown, optionally, the overall height h2 of the riveted column 411 after riveting is less than the maximum thickness H1 of the lower plastic 42 to ensure that the end surface of the riveted column 411 is not easily in contact with the electrode group 200 after riveting.

[0058] Further optionally, as Figure 6 As shown, the height h1 of the rivet post 411 before riveting is less than the maximum thickness H1 of the lower plastic 42. That is, before riveting, when the lower plastic 42 does not have any extrusion deformation in the height direction, the rivet post 411 cannot abut against the electrode group 200. This can prevent the rivet post 411 from accidentally touching the electrode group 200 when the riveting is not in place or there is an assembly error, and can further improve the insulation safety of the battery cell housing 100.

[0059] Optionally, the cross-section of the rivet post 411 before riveting is circular, and the cross-section of the rivet hole 421 is also circular. The difference between the diameter of the rivet hole 421 and the diameter of the cross-section of the rivet post 411 before riveting is in the range of 0.1mm-0.5mm, that is, along the circumference of the rivet post 411, the distance between its side wall and the inner wall of the rivet hole 421 is 0.05mm-0.25mm. If the gap between the rivet post 411 and the rivet hole 421 is too small, due to processing errors and assembly errors, there may be interference during the actual assembly process, which may easily cause the lower plastic 42 near the rivet hole 421 to bend and deform after riveting, thereby reducing the process yield. However, if the gap between the rivet post 411 and the rivet hole 421 is too large, the insertion of the rivet post 411 into the rivet hole 421 cannot ensure accurate positioning between the top cover 41 and the lower plastic 42, and a large assembly error may occur between the top cover 41 and the lower plastic 42, resulting in the battery cell housing 100 not meeting the required dimensions. Therefore, the difference between the diameter of the rivet hole 421 and the diameter of the cross section of the rivet post 411 before riveting should be limited to within the range of 0.1mm-0.5mm. This can avoid large assembly errors between the top cover 41 and the lower plastic 42, ensure the normal dimensions of the battery cell housing 100, and ensure that the lower plastic 42 does not bend or deform even when there are certain processing and assembly errors, thereby improving the process yield of the battery cell housing 100.

[0060] like Figure 7 As shown, optionally, the thickness a of the top cover 41 where the rivet posts 411 are not provided satisfies the following condition: 1mm≤a≤4mm. The value of a cannot be less than 1mm to ensure that the structural strength of the top cover 41 meets the requirements. The value of a cannot be greater than 4mm to avoid excessive length space occupied by the battery cell. Optionally, in this embodiment, the top cover 41 is a plain aluminum sheet.

[0061] Optionally, the maximum thickness H1 of the lower plastic 42 satisfies 1.5mm≤H1≤4mm. Optionally, the height of the reinforcing rib 422 of the lower plastic 42 is consistent with the height of the side wall of the weight-reducing groove, that is, the end face of the reinforcing rib 422 and the end face of the edge of the weight-reducing groove are on the same plane, and the maximum thickness H1 of the lower plastic 42 is the overall thickness at the reinforcing rib 422, or the overall height of the outer side at the edge of the weight-reducing groove. When the maximum thickness H1 of the lower plastic 42 is less than 1.5mm, the structural strength of the lower plastic 42 cannot be guaranteed, and the weight-reducing groove is too shallow, which may cause the riveted column 411 to protrude from the end face of the reinforcing rib 422 after riveting, making the riveted column 411 easily conductive with the pole group 200, or the height of the hanging platform of the riveted column 411 needs to be lowered, the riveting strength cannot be guaranteed, and the lower plastic 42 and the top cover 41 are easily dislocated. If the maximum thickness H1 of the lower plastic 42 is greater than 4mm, the lower plastic 42 takes up too much space and weighs too much, hindering the improvement of the battery cell's energy density. Therefore, to balance the battery cell's energy density, the structural strength of the lower plastic 42, and the connection strength between the lower plastic 42 and the top cover 41, the maximum thickness H1 of the lower plastic 42 must meet the requirement of 1.5mm≤H1≤4mm.

[0062] 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 dimensional conditions, it can ensure the connection strength between the lower plastic 42 and the top cover 41, the flatness of the lower plastic 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. After the top cover 41 and the lower plastic 42 of the second cover plate assembly 4 of the battery cell housing 100 of the battery cell are riveted, it is tested whether the rivet column 411 contacts the electrode group 200, whether the lower plastic 42 is deformed, and whether the top cover 41 and the lower plastic 42 are aligned. After the overall assembly of the battery cell is completed, a thermal runaway test is performed on the battery cell to detect whether there is a phenomenon of thermal runaway escalation.

[0063] Among them, the similarities of the battery cell casings 100 of the ten groups of examples and the eight groups of comparative examples are: the explosion-proof valves 2 are all arranged on the first side wall 11, the thickness a of the top cover 41 where the rivet column 411 is not arranged satisfies 1mm≤a≤4mm, and the maximum thickness H1 of the lower plastic 42 also satisfies 1.5mm≤H1≤4mm.

[0064] Table 1

[0065]

[0066] Specifically, Table 1 above shows the various dimensional parameters of the battery cell casing 100 of the battery cells of ten groups of examples, and their dimensional parameters all meet the above-mentioned restrictions. For example, the height h1 of the riveted column 411 before riveting is greater than the thickness t1 of the bottom of the weight-reducing groove, the height h1 of the riveted column 411 before riveting is less than the maximum thickness H1 of the lower plastic 42, and the difference between the aperture of the riveted hole 421 and the diameter of the cross section of the riveted column 411 before riveting is in the range of 0.1mm-0.5mm. After testing, the battery cell casing 100 of the battery cells of these ten groups of examples can achieve effective thermal and electrical separation. When the battery cell thermal runaway occurs, the insulation component at the output terminal will not melt and fail due to the thermoelectric element being too close to the output terminal, resulting in a short circuit and further escalation of thermal runaway. Furthermore, after passing through the rivet holes 421, the rivet posts 411 of the cell casings 100 of these ten examples are lower than the reinforcing ribs 422 of the lower plastic 42 and the sidewalls of the weight-reducing groove. After riveting, the rivet posts 411 will not be higher than the reinforcing ribs 422 of the lower plastic 42 or the sidewalls of the weight-reducing groove. Furthermore, after the lower plastic 42 is compressed along its thickness, the rivet posts 411 will not contact the electrode group 200, eliminating the risk of insulation failure. Furthermore, the rivet posts 411 of the cell casings 100 of these ten examples protrude from the bottom of the weight-reducing groove before riveting, ensuring a smooth and secure riveting operation. There is no loosening between the top cover 41 and the lower plastic 42, thus meeting quality requirements. Furthermore, the difference between the diameter of the rivet hole 421 and the cross-sectional diameter of the rivet post 411 before rivet pressing is within a reasonable range, the top cover 41 and the lower plastic 42 are accurately positioned, and there is no interference between the rivet post 411 and the rivet hole 421. Therefore, the battery cells of these ten examples have a higher process yield.

[0067] As shown in Table 1 above, the height h1 of the riveted studs 411 of the cell housing 100 of the battery cells of Comparative Example 1 before riveting is greater than the maximum thickness H1 of the lower plastic 42, that is, before riveting, the riveted studs 411 protrude 0.2 mm above the reinforcing ribs 422 and edge end faces of the lower plastic 42. After testing, the riveted studs 411 of the cell housing 100 of this group of battery cells are still higher than the reinforcing ribs 422 and edge end faces of the lower plastic 42 after riveting. After assembling the pole group 200, it was found that there is a risk of insulation failure, resulting in a low yield rate for this group of battery cells. However, when this group of battery cells was subjected to a thermal runaway test after assembly, no thermal runaway escalation phenomenon occurred, that is, this group of battery cells can achieve effective thermoelectric separation, and when the battery cells are in thermal runaway, the insulation components at the output terminals will not melt and fail due to the proximity of the thermoelectric elements.

[0068] The height h1 of the riveted studs 411 of the cell housing 100 of the battery cells of Comparative Example 2 before riveting was also greater than the maximum thickness H1 of the lower plastic 42. That is, before riveting, the riveted studs 411 protruded 0.2 mm above the reinforcing ribs 422 and edge end faces of the lower plastic 42. Testing showed that the riveted studs 411 of the cell housing 100 of this group of battery cells remained higher than the reinforcing ribs 422 and edge end faces of the lower plastic 42 even after riveting. After assembling the electrode group 200, some of the battery cells were found to have insulation failure, resulting in a low yield for this group of battery cells. However, when this group of battery cells was subjected to a thermal runaway test after assembly, no thermal runaway escalation occurred. This indicates that this group of battery cells can achieve effective thermoelectric separation, and in the event of thermal runaway, the insulation components at the output terminals will not melt and fail due to the close proximity of the thermoelectric elements.

[0069] The height h1 of the riveted posts 411 of the cell housing 100 of the battery cell of Comparative Example 3 before riveting is less than the thickness t1 of the bottom of the weight-reducing groove, that is, before riveting, the end face of the riveted post 411 is located in the riveting hole 421, and the height difference between the end face of the riveted post 411 and the inner wall surface of the bottom of the weight-reducing groove is 0.1 mm. After testing, the riveted posts 411 of the cell housing 100 of this group of battery cells could not be effectively riveted, and the connection between the lower plastic 42 and the top cover 41 was not firm, resulting in a low yield rate for this group of battery cells. However, when this group of battery cells was subjected to a thermal runaway test after assembly, no thermal runaway escalation occurred, that is, this group of battery cells can achieve effective thermoelectric separation, and when the battery cells are in thermal runaway, the insulation components at the output terminals will not melt and fail due to the thermoelectric being too close.

[0070] The height h1 of the riveted posts 411 of the cell housing 100 of the battery cell of Comparative Example 4 before riveting is also less than the thickness t1 of the bottom of the weight-reducing groove, that is, before riveting, the end face of the riveted post 411 is located in the riveting hole 421, and the height difference between the end face of the riveted post 411 and the inner wall surface of the bottom of the weight-reducing groove is 0.1 mm. After testing, the riveted posts 411 of the cell housing 100 of this group of battery cells were also unable to be effectively riveted, and the connection between the lower plastic 42 and the top cover 41 was not firm, resulting in a low yield rate for this group of battery cells. However, when this group of battery cells was subjected to a thermal runaway test after assembly, no thermal runaway escalation occurred, that is, this group of battery cells can achieve effective thermoelectric separation, and when the battery cells are in thermal runaway, the insulation components at the output terminals will not melt and fail due to the thermoelectric being too close.

[0071] The diameter of the rivet hole 421 of the battery cell of Comparative Example 5 is consistent with the diameter of the cross section of the rivet post 411 before riveting, that is, the difference between the two is 0, which is less than the minimum value of the optimal value range of 0.1mm. After testing, there is interference between the rivet hole 421 and the rivet post 411 of this group of battery cells, and the lower plastic 42 is bent and deformed after riveting, resulting in a low yield rate for this group of battery cells. However, when this group of battery cells was subjected to a thermal runaway test after assembly, no thermal runaway escalation occurred, that is, this group of battery cells can achieve effective thermal and electrical separation, and when the battery cells thermally runaway, the insulation components at the output terminals will not melt and fail due to the close proximity of the thermoelectric element.

[0072] The difference between the diameter of the rivet hole 421 of the battery cell of Comparative Example 6 and the diameter of the cross section of the rivet post 411 before riveting is 0.05mm, which is still less than the minimum value of the more optimal value range of 0.1mm. After testing, there is also interference between the rivet hole 421 and the rivet post 411 of this group of battery cells, and the lower plastic 42 is also bent and deformed after riveting, but the degree of deformation is not as severe as the degree of deformation of the lower plastic 42 of the battery cell of Comparative Example 5. However, the yield of the battery cell of Comparative Example 6 is also low. However, when this group of battery cells was subjected to a thermal runaway test after assembly, no thermal runaway escalation phenomenon occurred, that is, this group of battery cells can achieve effective thermoelectric separation, and when the battery cell thermal runaway occurs, the insulation component at the output terminal will not melt and fail due to the close proximity of thermoelectric elements.

[0073] The difference between the diameter of the rivet hole 421 of the battery cell of Comparative Example 7 and the diameter of the cross section of the rivet post 411 before riveting is 1.0 mm, which is greater than the maximum value of the optimal value range of 0.5 mm. After testing, the gap between the rivet hole 421 and the rivet post 411 of this group of battery cells is too large, and the positioning will deviate during riveting, causing the size of the second cover plate assembly 4 after riveting to not meet the requirements, so the yield of this group of battery cells is also low. However, when this group of battery cells was subjected to a thermal runaway test after assembly, no thermal runaway escalation occurred, that is, this group of battery cells can achieve effective thermoelectric separation, and when the battery cells are in thermal runaway, the insulation assembly at the output terminal will not melt and fail due to the thermoelectric being too close.

[0074] The difference between the diameter of the rivet hole 421 of the battery cell of Comparative Example 8 and the diameter of the cross section of the rivet post 411 before riveting is 0.7mm, which is still greater than the maximum value of the optimal value range of 0.5mm. After testing, the gap between the rivet hole 421 and the rivet post 411 of this group of battery cells is still too large, and positioning deviation may still occur during riveting. The size of the second cover plate assembly 4 of some battery cells after riveting does not meet the requirements, so the yield of this group of battery cells is also low, but higher than the yield of the battery cells of Comparative Example 7. However, when this group of battery cells was subjected to a thermal runaway test after assembly, no thermal runaway escalation occurred, that is, this group of battery cells can achieve effective thermoelectric separation, and when the battery cells are in thermal runaway, the insulation assembly at the output terminal will not melt and fail due to the thermoelectric being too close.

[0075] It can be seen that if the height h1 of the riveted column 411 before riveting is greater than the thickness t1 of the bottom of the weight-reducing groove, the height h1 of the riveted column 411 before riveting is less than the maximum thickness H1 of the lower plastic 42, and the difference between the aperture of the riveted hole 421 and the diameter of the cross section of the riveted column 411 before riveting is in the range of 0.1mm-0.5mm, it can be ensured that there is no risk of insulation failure at the second cover plate assembly 4 while ensuring thermoelectric separation and no thermal runaway escalation, and that the connection between the top cover 41 and the lower plastic 42 is firm, and the relative position between the two is also in line with the product design, the process yield of the battery cell is high.

[0076] 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.

[0077] 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.

[0078] By arranging the positive output terminal 31 and the negative output terminal 32 at one end of the cell housing 100 and arranging the explosion-proof valve 2 on the first side wall 11, and away from the positive output terminal 31 and the negative output terminal 32, the thermal and electrical distance can be increased, which helps prevent the output terminals from being affected by a mixture of high temperature and sparks during thermal runaway, and prevents the positive and negative short circuits from being aggravated due to the failure of the insulation at the output terminals, thereby escalating the thermal runaway. Therefore, the cell housing 100 can help prevent the escalation of thermal runaway and improve the safety of the cell. In addition, conventional cover plate assemblies are generally fixed between the poles and the top cover 41 to lock the lower plastic 42, but the second cover plate assembly 4 of this embodiment does not have a pole, and the lower plastic 42 is fixed to the top cover 41 by riveting, which can ensure the connection strength between the lower plastic 42 and the top cover 41, thereby preventing the lower plastic 42 from being misaligned or deformed, resulting in insulation failure.

[0079] In addition, the height h1 of the riveted column 411 of the battery cell before riveting is greater than the thickness t1 of the bottom of the weight-reducing groove, and the height h1 of the riveted column 411 before riveting is less than the maximum thickness H1 of the lower plastic 42. The difference between the aperture of the riveted hole 421 and the diameter of the cross section of the riveted column 411 before riveting is in the range of 0.1mm-0.5mm, which can ensure that there is no risk of insulation failure at the second cover plate assembly 4 of the battery cell under the premise that there is no thermal runaway escalation in the thermoelectric separation of the battery cell, and can ensure that the connection between the top cover 41 and the lower plastic 42 is firm, and the relative position between the two is also in line with the product design, so the process yield of the battery cell is relatively high.

[0080] 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: A shell body (1), wherein the shell body (1) is provided with a first opening and a second opening at both ends along its length direction, and one end of the shell body (1) along its width direction is a first side wall (11); A first cover plate assembly (3), the first cover plate assembly (3) being arranged to cover the first opening, 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) is arranged to cover the second opening, the second cover plate assembly (4) comprises a top cover (41) and a lower plastic (42), the top cover (41) has a rivet post (411) on its end surface facing the inner cavity of the battery cell housing (100), the lower plastic (42) is provided with a rivet hole (421) extending therethrough, the rivet post (411) and the rivet hole (421) being fixed by riveting; An explosion-proof valve (2), the explosion-proof valve (2) being arranged on a wall surface of the battery cell housing other than the first cover plate assembly (3).

2. The battery cell casing according to claim 1, wherein: The explosion-proof valve (2) is arranged on the first side wall (11) and is close to the second opening.

3. The battery cell casing according to claim 1, wherein: A weight-reducing groove is provided on the end surface of the lower plastic (42) facing the inner cavity of the battery cell housing (100), and the rivet hole (421) is provided at the bottom of the weight-reducing groove.

4. The battery cell casing according to claim 3, characterized in that: A reinforcing rib (422) is convexly provided on the bottom of the weight-reducing groove, and the reinforcing rib (422) divides the weight-reducing groove into a plurality of sub-grooves (423).

5. The battery cell casing according to claim 4, characterized in that: At least one riveting hole (421) is provided at the bottom of each of the sub-slots (423).

6. The battery cell casing according to any one of claims 3 to 5, characterized in that: Before riveting, the height h1 of the riveting column (411) is greater than the thickness t1 of the bottom of the weight-reducing groove; And / or, after riveting, the overall height h2 of the riveted column (411) is less than the maximum thickness H1 of the lower plastic (42).

7. The battery cell casing according to claim 6, characterized in that: Before riveting, the height h1 of the riveting column (411) is smaller than the maximum thickness H1 of the lower plastic (42).

8. The battery cell casing according to any one of claims 1 to 5, characterized in that: The cross section of the riveted column (411) before riveting is circular, the cross section of the riveted hole (421) is also circular, and the difference between the diameter of the riveted hole (421) and the cross section of the riveted column (411) before riveting is in the range of 0.1 mm to 0.5 mm.

9. The battery cell casing according to any one of claims 1 to 5, characterized in that: The thickness a of the top cover (41) where the riveted column (411) is not provided satisfies 1mm≤a≤4mm; And / or, the maximum thickness H1 of the lower plastic (42) satisfies 1.5 mm ≤ H1 ≤ 4 mm.

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 inside the battery cell casing (100).

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