Shell of battery cell and battery cell comprising same

Abstract

The utility model provides a shell of a battery cell, which comprises a shell body provided with a through hole, the shell body is made of steel, the thickness direction of the shell body is a first direction, and in the first direction, the shell body comprises a first side and a second side which are opposite to each other; a positive terminal passing through the through hole; the upper insulating part is arranged between the positive terminal and the shell body, so that the positive terminal is insulated from the shell body; and the negative terminal comprises a first terminal layer and a second terminal layer which are arranged along the first direction, the first terminal layer is electrically connected with the second terminal layer, the second terminal layer is electrically connected with the first side, the second terminal layer is made of steel, and the material of the first terminal layer is different from that of the second terminal layer. The shell body is made of steel instead of aluminum alloy, so that the energy density of the manufactured battery cell can be improved. The negative electrode of the electrode assembly is led out through the shell body, the second terminal layer of the negative electrode terminal and the first terminal layer, so that parts required by the shell of the battery cell are reduced, the structure is simplified, and the cost is reduced.

Description

Technical Field

[0001] This utility model relates to a battery cell housing and a battery cell containing the housing. Background Technology

[0002] A prismatic battery cell generally includes at least a cell housing and an electrode assembly disposed inside the cell housing. Positive and negative electrodes are led out from the electrode assembly and then connected to the positive and negative terminals disposed on the surface of the cell housing. The cell housing is mostly made of aluminum alloy. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the defects of low energy density and high production and assembly costs of existing square-shell batteries, and to provide a battery cell casing and a battery cell containing the casing.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] A housing for a battery cell, comprising:

[0006] The shell body has a through hole. The shell body is made of steel. The thickness direction of the shell body is a first direction. In the first direction, the shell body includes a first side and a second side opposite to each other.

[0007] The positive terminal passes through the through hole;

[0008] An upper insulating element is disposed between the positive terminal and the housing body to insulate the positive terminal from the housing body;

[0009] The negative terminal includes a first terminal layer and a second terminal layer disposed along the first direction. The first terminal layer and the second terminal layer are electrically connected, and the second terminal layer is electrically connected to the first side. The material of the second terminal layer is steel, and the material of the first terminal layer is different from that of the second terminal layer.

[0010] The casing of this battery cell is made of steel instead of aluminum alloy, which can ensure structural strength while reducing the thickness, thereby improving the space utilization rate inside the battery cell casing and increasing the energy density of the manufactured battery cell.

[0011] The negative terminal of the housing comprises two parts: a first terminal layer and a second terminal layer. The second terminal layer is made of steel and is electrically connected to the first side of the housing body. The first terminal layer, made of a different material, is used to connect to external electrical connectors, leading the negative terminal of the electrode assembly of the battery cell housed within the housing body outwards via the second side of the housing body, the second terminal layer, and the first terminal layer of the negative terminal. This structural design reduces the number of components required for the battery cell housing, simplifies the structure, and reduces production and assembly costs.

[0012] Meanwhile, the steel shell carries a negative charge, which prevents the shell from corroding.

[0013] Preferably, the first side has a recessed portion that is recessed toward the second side, and at least a portion of the second terminal layer is accommodated within the recessed portion.

[0014] By providing a recessed portion that can partially accommodate the second terminal layer on the surface where the shell body is electrically connected to the second terminal layer, the recessed structure of the recessed portion can be used to position the second terminal layer and can also wrap the second terminal layer to improve the connection strength between the negative terminal including the second terminal layer and the shell body. On the other hand, it can also reduce the space occupied by the negative terminal including the second terminal layer on the first side of the shell body, thereby further improving the space utilization rate of the battery cell.

[0015] Preferably, the depth of the recess is greater than or equal to half the thickness of the shell body.

[0016] The recessed depth is at least greater than half the thickness of the shell body to ensure sufficient depth for accommodating and positioning the second terminal layer, thereby further improving the accuracy of positioning the second terminal layer and the strength of the connection. Furthermore, since the shell body is made of steel, its structural strength is relatively high, and machining a deep recess on the shell body surface will not affect the dimensional accuracy and surface flatness of the shell body.

[0017] Preferably, the recess depth of the recess is D, where 0.8mm ≤ D ≤ 2mm.

[0018] By ensuring the recess depth is greater than or equal to 0.8 mm, insufficient penetration and welding strength can be avoided when the second terminal layer of the negative electrode post is connected to the shell body via welding methods such as laser welding due to an excessively shallow recess. Simultaneously, by ensuring the recess depth is less than or equal to 2 mm, the strength of the rounded joint between the recessed and unrecessed portions, formed by material deformation, can be prevented from weakening due to excessively deep recesses, thus improving manufacturability.

[0019] Preferably, the second side has a protrusion corresponding to the position of the recess.

[0020] By providing a protrusion on the second side of the shell body corresponding to the recess, the processing difficulty can be reduced. That is, while processing the recess on the outside of the shell body, a protrusion is formed on the opposite side surface of the shell body. Furthermore, the surface that is more protruding than other surfaces of the shell body is also conducive to the connection of the negative electrode tab.

[0021] Preferably, both the positive and negative terminals are disposed on the first side of the shell body, and on the second side, the protrusion is at the same height as the positive terminal.

[0022] By using a structure where the protrusion is at the same height as the positive terminal, the positive tab of the electrode assembly for connecting the positive terminal and the negative tab for connecting the negative terminal can be kept in balance, avoiding the situation where one end is pulled and the connection becomes unstable. On the other hand, it also reduces the difficulty of connection.

[0023] Preferably, there is a gap between the inner peripheral side surface of the recess and the outer peripheral side surface of the second terminal layer, and the size of the gap is M, 0.1mm≤M≤0.2mm.

[0024] A gap is created between the inner peripheral side of the recess and the outer peripheral side of the second terminal layer to facilitate the installation of the negative terminal in the recess. The gap should be less than or equal to 0.2 mm to avoid affecting the positioning of the recess on the second terminal layer if the gap is too large. At the same time, the gap should be greater than or equal to 0.1 mm to avoid affecting the pre-installation of the second terminal layer relative to the recess if the gap is too small.

[0025] Preferably, on the first side, the surface of the second terminal layer is flush with the surface of the housing body; and / or,

[0026] On the first side, the surface of the first terminal layer protrudes from the surface of the shell body.

[0027] By aligning the outer surface of the second terminal layer with the first side of the housing body in the first direction, clamping and positioning during welding is facilitated. Simultaneously, the outer surface of the first terminal layer protrudes from the first side surface of the housing body, facilitating welding to external electrical connectors via the outer surface of the first terminal layer.

[0028] Preferably, along the first direction, the projection of the first terminal layer onto the surface of the second terminal layer is located within the range of the second terminal layer.

[0029] By positioning the projection of the first terminal layer onto the surface of the second terminal layer within the range of the second terminal layer, laser penetration welding can be performed on the portion of the second terminal layer surface that does not cover the first terminal layer, thereby welding the second terminal layer to the shell body via laser penetration welding.

[0030] Preferably, along the first direction, the area where the projection of the second terminal layer is not covered by the projection of the first terminal layer is an annular area formed along the edge of the projection of the second terminal layer.

[0031] The area on the second terminal layer not covered by the first terminal layer is annular. Laser penetration welding is performed on the second terminal layer through this annular area, which can improve the welding strength between the second terminal layer and the shell body.

[0032] Preferably, the minimum width dimension of the annular region is Nmin, where Nmin ≥ 0.4 mm;

[0033] And / or, the maximum width of the annular region is Nmax, where Nmax ≤ 0.8 mm.

[0034] The minimum width dimension Nmin of the annular region is set to be greater than or equal to 0.4 mm to avoid the annular region being too small and unable to provide sufficient space for laser penetration welding. At the same time, the maximum width dimension Nmax of the annular region is set to be less than or equal to 0.8 mm to avoid the annular region being too large and causing the area of ​​the first terminal layer to be too small, which would affect the welding with external electrical connectors.

[0035] Preferably, the housing further includes an annular seal fixed between the second terminal layer and a first side of the housing body.

[0036] When welding the negative electrode tab of the electrode assembly to the second side of the housing body, there is a possibility of welding through the housing body, causing a connection between the first and second sides of the housing body, allowing electrolyte located on the second side to leak into the first side. To address this issue, an annular seal is provided between the second terminal layer and the first side of the housing body to seal the area of ​​the first side surrounded by the annular seal. This ensures that when the negative electrode tab of the electrode assembly is welded to the housing body within the area surrounded by the annular seal, even if the housing body is welded through during the welding process, any electrolyte leakage to the first side of the housing body is contained within the area enclosed by the annular seal and cannot leak outwards.

[0037] Preferably, the welding area between the second terminal layer and the shell body is located on the outside of the annular seal.

[0038] The welding area between the second terminal layer and the shell body is located on the outside of the annular seal, meaning that the projection of the welding area between the second terminal layer and the shell body on the surface of the shell body is within the sealing range of the annular seal.

[0039] Specifically, when the second terminal layer of the negative terminal is welded to the first side of the casing, there is a possibility of weld penetration of the second terminal layer, causing the electrolyte on the first side of the casing to continue to leak outward through the weld-through second terminal layer. By placing the welding area between the second terminal layer and the casing on the outside of the annular seal, the continued leakage of electrolyte within the area surrounded by the annular seal is prevented.

[0040] Preferably, the surface of the second terminal layer facing the first side and / or the first side also has a sealing groove for accommodating the annular seal.

[0041] By providing a sealing groove on the first side surface of the second terminal layer or the shell body to accommodate the annular seal, the annular seal can be pre-positioned before the second terminal layer is connected to the shell body, thus avoiding positional displacement of the annular seal and affecting the sealing effect.

[0042] Preferably, in a second direction perpendicular to the first direction, one of the upper insulating member and the shell body has an outwardly protruding positioning portion, and the other has a receiving portion that mates with the positioning portion.

[0043] Because the shell body is made of steel and is relatively thin, it is not possible to create a deep recess on the surface of the shell body to accommodate the upper insulator and the positive terminal to prevent rotation. Therefore, a positioning part extending in the second direction is provided between the upper insulator and the shell body to cooperate with the receiving part, thereby improving the anti-rotation capability of the upper insulator relative to the shell body by providing additional contact area.

[0044] Preferably, the shell body includes a top cover and a side shell, the top cover and the side shell being electrically connected to an opening, and together forming an accommodating space.

[0045] The casing body forms a receiving space by combining a top cover and side shells to house the electrode assembly of the battery cell. The positive and negative terminals can be set on the top cover or side shell according to actual location requirements to bring out the positive and negative terminals of the electrode assembly housed in the casing body.

[0046] Preferably, both the shell body and the second terminal layer are made of 304 stainless steel; and / or,

[0047] In the first direction, the negative terminal is rectangular in shape, and rounded corners are provided at the four corners of the negative terminal; and / or,

[0048] On the first side, the positive terminal is at the same height as the first terminal layer; and / or,

[0049] The thickness of the second terminal layer is T1, 0.6mm ≤ T1 ≤ 1mm; and / or,

[0050] The thickness of the first terminal layer is T2, 0.6mm ≤ T2 ≤ 1mm; and / or,

[0051] The thickness of the shell body is T3, where 0.8mm ≤ T3 ≤ 1.2mm.

[0052] The shell body and the second terminal layer are made of 304 stainless steel to obtain relatively better structural strength and further improve corrosion resistance.

[0053] The negative terminal is rectangular in shape in the first direction to provide better anti-rotation capability. Rounded corners are provided at the four corners of the negative terminal to prevent sharp corner structures from damaging other components.

[0054] The thickness of the second terminal layer is greater than or equal to 0.6 mm to avoid insufficient strength due to excessive thickness and difficulty in connecting with other parts. At the same time, the thickness of the second terminal layer is less than or equal to 1 mm to minimize weight and cost while meeting the strength and connection requirements with other parts.

[0055] The thickness of the first terminal layer is greater than or equal to 0.6 mm to avoid insufficient strength due to excessive thickness and difficulty in connecting with other parts. At the same time, the thickness of the first terminal layer is less than or equal to 1 mm to minimize weight and cost while meeting the strength and connection requirements with other parts.

[0056] The shell body has a thickness of 0.8 mm or more to avoid affecting strength due to excessive thinness. At the same time, the shell body has a thickness of 1.2 mm or less to minimize weight and cost while meeting strength requirements.

[0057] A battery cell comprising:

[0058] The casing of the battery cell as described above.

[0059] The positive and progressive effects of this utility model are as follows:

[0060] (1) By replacing aluminum alloy with steel as the material used for the shell body, the structural strength can be ensured while reducing the thickness, improving the space utilization rate inside the shell of the battery cell and increasing the energy density of the battery cell.

[0061] (2) The negative terminal of the housing consists of two parts: a first terminal layer and a second terminal layer. The negative terminal of the electrode assembly is led outward through the housing body, the second terminal layer and the first terminal layer of the negative terminal to reduce the number of components required for the battery cell housing, simplify the structure and reduce production and assembly costs.

[0062] (3) The shell body is negatively charged, which can prevent the shell body from rusting. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the battery cell structure of Embodiment 1 of this utility model.

[0064] Figure 2 This is an exploded structural diagram of the battery cell in Embodiment 1 of this utility model.

[0065] Figure 3This is a schematic diagram of the top cover of Embodiment 1 of this utility model.

[0066] Figure 4 This is an exploded structural diagram of the top cover portion of the shell of Embodiment 1 of this utility model.

[0067] Figure 5 This is a top view of the top cover portion of the shell in Embodiment 1 of this utility model.

[0068] Figure 6 for Figure 5 A sectional view of the CC section.

[0069] Figure 7a for Figure 6 Sectional view of part D (I).

[0070] Figure 7b for Figure 6 Sectional view of part D (II).

[0071] Figure 8 This is an exploded structural diagram of the negative terminal and the top cover of Embodiment 1 of this utility model.

[0072] Figure 9 This is a schematic diagram of the top cover portion of the shell in Embodiment 1 of this utility model.

[0073] Figure 10 This is a schematic diagram of the layout of the welding sealing area on the surface of the recessed part of the top cover in Embodiment 1 of this utility model.

[0074] Figure 11 This is a schematic diagram of one side of the battery cell in Embodiment 2 of this utility model.

[0075] Figure 12 This is a schematic diagram of the other side of the battery cell in Embodiment 2 of this utility model.

[0076] Explanation of reference numerals in the attached figures:

[0077] 100 cells

[0078] Casing 10

[0079] Shell body

[0080] Top cover 1, first direction A, second direction B

[0081] Through hole 11, recessed portion 12, protruding portion 13, receiving portion 14, injection hole 15

[0082] Side shell 2, opening 21

[0083] Positive terminal 3, positive terminal rivet block 31, positive terminal post 32

[0084] Negative terminal 4, first terminal layer 41, second terminal layer 42, annular region 43, sealing groove 44

[0085] Upper insulating component 5, positioning part 51

[0086] Lower insulation component 6

[0087] Sealing ring 7

[0088] 8 ring seals

[0089] Electrode assembly 20, positive electrode tab 201, negative electrode tab 202

[0090] Insulating sheet 30 Detailed Implementation

[0091] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0092] Example 1

[0093] like Figure 1 and Figure 2 As shown, this utility model provides a housing 10 for a battery cell 100. The housing 10 includes a top cover 1 and a side shell 2. One end of the side shell 2 is open to form an opening 21, and the other end is closed. The top cover 1 closes the opening 21 of the side shell 2 to form a receiving space for accommodating the electrode assembly 20 of the battery cell 100. The positive terminal 3 and the negative terminal 4 are both disposed on the top cover 1 to lead out the positive and negative terminals of the electrode assembly 20 (that is, the top cover 1 in this embodiment is the shell body of the housing 10). The liquid injection hole 15 is disposed between the positive terminal 3 and the negative terminal 4. The explosion-proof port is disposed at the bottom of the side shell 2 (not shown in the figure).

[0094] The specific structure of cell 100 is described below: Figure 2 As shown, the battery cell 100 includes the aforementioned housing 10, electrode assembly 20, and insulating sheet 30. The insulating sheet 30 wraps around the electrode assembly 20 and is disposed together with the electrode assembly 20 within the housing space of the housing 10. The positive electrode tab 201 and negative electrode tab 202 of the electrode assembly 20 are led out through the positive terminal 3 and negative terminal 4 located on the housing body of the housing 10, respectively, and are connected to the electrical connectors outside the battery cell 100 through the positive terminal 3 and negative terminal 4 to transmit power to the outside.

[0095] specific Figure 3As shown, in this embodiment, a through hole 11 is provided on the top cover 1. The top cover 1 is made of steel, and its thickness direction is a first direction A. In the first direction A, the top cover 1 includes a first side a and a second side b. The side of the top cover 1 away from the electrode assembly 20 is the first side a, and the side closer to the electrode assembly 20 is the second side b. The top cover 1 of the battery cell 100 housing 10 is made of steel instead of aluminum alloy, which can ensure structural strength while reducing the thickness, thereby improving the space utilization rate within the battery cell 100 housing 10 composed of the top cover 1 and increasing the energy density of the manufactured battery cell 100. At the same time, in this embodiment, the side shell 2 connected to the top cover 1 is also made of steel to facilitate welding of the top cover 1 and the side shell 2. At the same time, the side shell 2 is also made of steel, which can also ensure structural strength while reducing the thickness, thereby improving the space utilization rate within the housing 10.

[0096] like Figure 4 As shown, the positive terminal 3 passes through the through hole 11 of the top cover 1, and the upper insulating member 5 is disposed between the positive terminal 3 and the first side a of the top cover 1 to insulate the positive terminal 3 from the shell body. The negative terminal 4 includes a first terminal layer 41 and a second terminal layer 42 disposed along the first direction A. The first terminal layer 41 and the second terminal layer 42 are electrically connected, and the second terminal layer 42 is electrically connected to the first side a. The second terminal layer 42 is made of steel, and the material of the first terminal layer 41 is different from that of the second terminal layer 42.

[0097] like Figure 7a and Figure 8 As shown, the negative terminal 4 of the housing 10 comprises two parts: a first terminal layer 41 and a second terminal layer 42. The second terminal layer 42 is made of steel and is electrically connected to the first side a of the top cover 1. The first terminal layer 41 is made of a different material than the second terminal layer 42 and is used to connect to external electrical connectors. The negative electrode tab 202 of the electrode assembly 20 of the battery cell 100 housed inside the top cover 1 is led outward through the second side b of the top cover 1, the second terminal layer 42 of the negative terminal 4, and the first terminal layer 41. This structural arrangement reduces the number of components required for the housing 10 of the battery cell 100, simplifies the structure, and reduces production and assembly costs. Simultaneously, the steel top cover 1 carries a negative charge, preventing corrosion of the housing body.

[0098] Specifically, in this embodiment, the first terminal layer 41 is made of aluminum alloy to accommodate an aluminum external electrical connector, which is reliably connected via welding. In other embodiments, the material of the first terminal layer 41 can be adjusted according to the material of the external electrical connector. Furthermore, in this embodiment, the first terminal layer 41 and the second terminal layer 42 are connected via a metal composite method. Of course, in other embodiments, the first terminal layer 41 and the second terminal layer 42 can also be connected using other methods existing in the prior art, such as riveting or welding. Additionally, in this embodiment, both the top cover 1 and the second terminal layer 42 of the negative terminal 4 are made of 304 stainless steel to achieve relatively better structural strength and corrosion resistance, significantly improving durability.

[0099] like Figure 3 , Figure 6 and Figure 7a As shown, the top cover 1 has a recessed portion 12 on the first side a, which is recessed towards the second side b, and the second terminal layer 42 is accommodated within the recessed portion 12. By providing the recessed portion 12 that can accommodate the second terminal layer 42 on the surface of the top cover 1 where it is electrically connected to the second terminal layer 42, the recessed structure of the recessed portion 12 can be used to position the second terminal layer 42, and can also wrap around the second terminal layer 42 to improve the connection strength between the negative terminal 4, including the second terminal layer 42, and the top cover 1. On the other hand, it can also reduce the space occupied by the negative terminal 4, including the second terminal layer 42, on the first side a of the top cover 1, further improving the space utilization of the battery cell 100. Specifically, in this embodiment, the recessed portion 12 can accommodate the entire second terminal layer 42 of the negative terminal 4, so that on the first side a of the top cover 1, the surface of the second terminal layer 42 is flush with the surface of the top cover 1, which facilitates clamping and positioning during the welding process. In other embodiments, the depth of the recess 12 may be set to accommodate only the second terminal layer 42 of the portion 14, such that the surface of the second terminal layer 42 protrudes relative to the first side a. Additionally, in this embodiment, the surface of the first terminal layer 41 protrudes from the surface of the top cover 1, facilitating soldering to external electrical connectors via the outer surface of the first terminal layer 41.

[0100] In addition, such as Figure 7aAs shown, corresponding to the position of the recess 12 on the first side a of the top cover 1, a protrusion 13 is provided on the second side b of the top cover 1. That is, while the recess 12 is machined on the outer side (first side a) of the top cover 1, a protrusion 13 is formed on the opposite surface of the top cover 1 to allow the negative electrode tab 202 of the electrode assembly 20 to be electrically connected. Furthermore, the surface that is more convex than other surfaces of the top cover 1 also facilitates the connection of the negative electrode tab 202. The protrusion 13 can be formed when the recess 12 is machined on the surface of the top cover 1 by means of stamping or the like. That is, by using a stamping process to simultaneously form both the protrusion and the recess on both sides of the top cover 1, the processing difficulty can be reduced. The protrusion 13 is used for connection of the negative electrode tab 202 of the electrode assembly 20, and the recess 12 is used for accommodating and positioning.

[0101] like Figure 6 As shown, in this embodiment, on the first side a of the top cover 1, both the positive terminal 3 and the negative terminal 4 protrude from the first side a to facilitate soldering with external electrical connectors. Since the negative terminal 4 is composed of a first terminal layer 41 and a second terminal layer 42 made of different materials, and most of the second terminal layer 42 is located within the recess 12 of the top cover 1, the positive terminal 3 is slightly higher than the first terminal layer 41 of the negative terminal 4. In other embodiments, the height of the positive terminal 3 can be made the same as the height of the first terminal layer 41 of the negative terminal 4 by thickening the negative terminal 4 or thinning the positive terminal 3, to further facilitate the connection of external electrical connectors.

[0102] In this embodiment, on the second side b of the top cover 1, both the protrusion 13 of the top cover 1 and the positive terminal 3 protrude from the second side b to facilitate electrical connection with the positive tab 201 and negative tab 202 of the electrode assembly 20. Since the protrusion 13, which is electrically connected to the negative tab 202, is formed by stamping in this embodiment, considering the thickness and machinability of the top cover 1, it cannot protrude as much as the positive terminal 3. Therefore, the positive terminal 3 is slightly higher than the protrusion 13 of the top cover 1. In other embodiments, the protrusion 13 can be made to protrude more relative to the second side b of the top cover 1 by changing the processing technology, so that the height of the protrusion 13 is the same as that of the positive terminal 3, making it easier to electrically connect with the positive tab 201 and negative tab 202 of the electrode assembly 20.

[0103] like Figure 7b As shown, the recessed depth of the recess 12 is D. The recessed depth D should be greater than or equal to half the thickness of the top cover 1 to ensure that the recessed portion 12 has sufficient depth to accommodate and position the second terminal layer 42, thereby further improving the accuracy of positioning the second terminal layer 42 and the strength of the connection with the second terminal layer 42. Furthermore, since the top cover 1 is made of steel, its structural strength is relatively high, and machining a deeper recess on the surface of the top cover 1 will not affect the dimensional accuracy and surface flatness of the shell body.

[0104] In addition, the recess depth D should be greater than or equal to 0.8 mm to avoid insufficient penetration and welding strength when the second terminal layer 42 of the negative electrode post is connected to the top cover 1 by welding methods such as laser welding if the recess is too shallow. At the same time, the recess depth D of the recessed part 12 should be less than or equal to 2 mm to avoid the strength of the rounded joint formed by the material extension deformation between the recessed part 12 and the non-recessed part of the top cover 1 weakened due to excessive recess, thus improving manufacturability.

[0105] like Figure 8 As shown, there is a gap between the inner peripheral side c of the recessed portion 12 of the top cover 1 and the outer peripheral side d of the second terminal layer 42 of the negative terminal 4 after assembly (see [reference]). Figure 7b This gap M is designed to facilitate the installation of the negative terminal 4 into the recess 12 of the top cover 1. The preferred size range for this gap M is 0.1mm ≤ M ≤ 0.2mm. The gap M should be less than or equal to 0.2mm to avoid excessively large gaps affecting the positioning of the recess 12 on the second terminal layer 42. Simultaneously, the gap M should be greater than or equal to 0.1mm to avoid excessively small gaps affecting the pre-installation of the second terminal layer 42 relative to the recess 12.

[0106] like Figure 7b As shown, the other dimensional parameters of the top cover 1 portion of the housing 10 also have a preferred range of size selection. The thickness of the second terminal layer 42 of the negative terminal 4 is T1, and the preferred size range of thickness T1 is 0.6mm ≤ T1 ≤ 1mm; the thickness of the first terminal layer 41 of the negative terminal 4 is T2, and the preferred size range of thickness T2 is 0.6mm ≤ T2 ≤ 1mm; while the thickness of the top cover 1 is T3, and the preferred size range of thickness T3 is 0.8mm ≤ T3 ≤ 1.2mm. The thickness of the top cover 1 is greater than or equal to 0.8mm to avoid affecting strength due to excessive thinness, while the thickness of the top cover 1 is less than or equal to 1.2mm to maximize weight and cost reduction while meeting strength requirements.

[0107] like Figure 7a and Figure 8 As shown, along the first direction A, the projection of the first terminal layer 41 of the negative terminal 4 onto the surface of the second terminal layer 42 lies within the range of the second terminal layer 42, so that a portion of the second terminal layer 42 is not covered by the first terminal layer 41. This allows for laser penetration welding of the portion of the second terminal layer 42 that is not covered by the first terminal layer 41, enabling a welded connection between the second terminal layer 42 and the top cover 1 via laser penetration welding. Compared to other welding methods, laser penetration welding provides a higher connection strength.

[0108] Specifically, such as Figure 8 and Figure 9As shown, in this embodiment, the area of ​​the projection of the second terminal layer 42 not covered by the projection of the first terminal layer 41 is an annular region 43 formed along the edge of the projection of the second terminal layer 42. That is, the first terminal layer 41 covers the central area of ​​the surface of the second terminal layer 42, while the peripheral edge area of ​​the second terminal layer 42 is not covered by the first terminal layer 41. The uncovered annular region 43 is used for laser penetration welding to penetrate the interior of the second terminal layer 42 and achieve a reliable connection with the top cover 1. Under this structural arrangement, the first terminal layer 41 has a complete and large area for welding with external point connectors, improving the reliability of the electrical connection.

[0109] like Figure 7b and Figure 8 As shown, the width N of the annular region 43 on the second terminal layer 42 that is not covered by the first terminal layer 41 should be set within a reasonable range. The minimum width Nmin of the annular region 43 should be greater than or equal to 0.4 mm to avoid the annular region 43 being too small and unable to provide sufficient space for laser penetration welding. At the same time, the maximum width Nmax of the annular region 43 should be less than or equal to 0.8 mm to avoid the annular region 43 being too large and causing the area of ​​the first terminal layer 41 to be too small, affecting the welding with external electrical connectors.

[0110] like Figure 2 As shown, since the top cover 1 is made of steel, its thickness T3 is thinner compared to other materials such as aluminum alloy, typically ranging from 0.8mm ≤ T3 ≤ 1.2mm. Therefore, when welding the negative electrode tab 202 of the electrode assembly 20 to the second side b of the top cover 1, there is a possibility of welding through the top cover 1, causing a connection between the first side a and the second side b of the top cover 1. In this case, after the problematic top cover 1 is assembled into the battery cell 100 and filled with electrolyte, the internal electrolyte may leak from the second side b of the top cover 1 to the first side a.

[0111] To address the aforementioned issues, in this embodiment, as follows: Figure 4 and Figure 7a As shown, the housing 10 also includes an annular seal 8, which is fixed between the first side a of the top cover 1 and the second terminal layer 42 of the negative terminal 4. The annular seal 8 is clamped and fixed by the connection between the second terminal layer 42 and the top cover 1. In this case, as long as the welding area between the second side b of the top cover 1 and the negative electrode tab 202 of the electrode assembly 20 is within the surrounding range of the annular seal 8, even if the top cover 1 is welded through during the welding process, the electrolyte leakage to the first side a of the top cover 1 will still be within the surrounding range of the annular seal 8 and will not be able to leak outward.

[0112] Specifically, such as Figure 10As shown, the sealing range of the annular seal 8 on the first side a of the top cover 1 is f, and the welding area between the negative electrode lug 202 of the motor assembly and the second side b of the top cover 1 is projected onto the first side a of the top cover 1, forming the projection area e. From Figure 10 As can be seen, on the surface of the top cover 1, the projected area e is located within the sealing range f. Therefore, even if the top cover 1 is welded through, the leaked electrolyte will be confined to the inside of the sealing range f where the annular seal 8 is located, and cannot continue to leak outward.

[0113] Meanwhile, when the second terminal layer 42 of the negative terminal 4 is welded to the first side a of the top cover 1, there is a possibility that the second terminal layer 42 may be burned through, causing the electrolyte located on the first side a of the top cover 1 to continue to leak outward through the burned-through second terminal layer 42. Therefore, in this embodiment, as Figure 10 As shown, the welding area g between the second terminal layer 42 of the negative terminal 4 and the top cover 1 on the first side a is located outside the sealing range f of the annular seal 8. That is, the welding area between the second terminal layer 42 and the top cover 1 is located outside the annular seal 8. This is to separate the welding area g of the negative terminal 4 relative to the top cover 1 on the first side a from the projection area e of the welding area e of the negative electrode tab 202 relative to the top cover 1 on the first side a by setting the annular seal 8, so as to prevent the electrolyte from continuing to leak out through the welded second terminal layer 42.

[0114] like Figure 7a As shown, in this embodiment, by forming a sealing groove 44 on the surface of the second terminal layer 42 of the negative terminal 4 facing the first side a of the top cover 1 to accommodate the annular seal 8, the annular seal 8 is pre-positioned before the negative terminal 4 and the top cover 1 are fully welded, thereby improving the sealing effect. Of course, in other embodiments, the sealing groove 44 can also be formed on the first side a of the top cover 1, or simultaneously on the second terminal layer 42 of the top cover 1 and the negative terminal 4 to accommodate the annular seal 8.

[0115] like Figure 4As shown, in this embodiment, the positive terminal 3 comprises two parts: a positive electrode riveting block 31 located on the first side a of the top cover 1 and a positive electrode post 32 located on the second side b of the top cover 1. The lower surface of the positive electrode post 32 is used for electrical connection with the positive electrode tab 201 of the electrode assembly 20. The upper end of the positive electrode post 32 extends through the through hole 11 of the top cover 1 and is connected to the positive electrode riveting block 31 by riveting. In addition, an upper insulating member 5 is disposed between the positive electrode riveting block 31 and the top cover 1 to achieve insulation between the positive electrode riveting block 31 and the top cover 1 and prevent short circuit. A lower insulating member 6 is disposed between the positive electrode post 32 and the top cover 1 to achieve insulation between the positive electrode post 32 and the top cover 1 and prevent short circuit. A sealing ring 7 is sleeved on the surface of the positive electrode post 32, and the outer surface of the sealing ring 7 contacts and seals the through hole 11 of the top cover 1 to prevent electrolyte leakage from the second side b of the top cover 1 through the through hole 11.

[0116] like Figure 9 As shown, in the first direction A, both the positive terminal 3 and the negative terminal 4 are rectangular in shape, and rounded corners are provided at the four corners of the positive terminal 3 and the negative terminal 4.

[0117] To achieve the anti-spinning objective of the positive extremum 3, such as Figure 4 As shown, a recess is provided on the first side a of the top cover 1 corresponding to the position of the upper insulating member 5 and the positive electrode riveting block 31 to accommodate the upper insulating member 5 and the positive electrode riveting block 31 and prevent the positive electrode riveting block 31 from rotating. However, since the top cover 1 is made of steel, its thickness can be thinner than that of aluminum alloy, so it is not possible to provide a recess that is too deep to accommodate the upper insulating member 5 and the positive electrode riveting block 31, resulting in limited anti-rotation capability. Therefore, in the second direction B perpendicular to the first direction A, the upper insulating member 5 has an outwardly protruding positioning part 51, and the surface of the first side a of the top cover 1 has a receiving part 14 that mates with the positioning part 51. By providing the additionally protruding positioning part 51 on the upper insulating member 5 within the receiving part 14 on the first side a of the top cover 1, the anti-rotation capability is improved by providing additional contact area. Of course, in other embodiments, the outwardly protruding positioning part 51 can also be provided on the surface of the first side a of the top cover 1, and a corresponding receiving part 14 can be provided on the upper insulating member 5 to achieve the same purpose of improving the anti-rotation effect.

[0118] like Figure 1 and Figure 2As shown, this utility model provides a battery cell 100 including the aforementioned housing 10. By replacing aluminum alloy with steel as the material used for the top cover 1 and side shell 2, structural strength can be ensured while reducing thickness, improving the space utilization within the housing 10 and increasing the energy density of the battery cell 100. Simultaneously, the negative electrode of the electrode assembly 20 of the battery cell 100 is led outwards via the top cover 1, the second terminal layer 42 of the negative terminal 4, and the first terminal layer 41, which reduces the number of components required for the battery cell 100, simplifies the structure, and reduces production and assembly costs. Furthermore, the top cover 1 and side shell 2 are negatively charged due to their connection with the negative electrode tab 202 of the electrode assembly 20, which prevents corrosion.

[0119] Example 2

[0120] This embodiment provides a housing 10 for a battery cell 100, the structure of which is roughly the same as that of the housing 10 provided in Embodiment 1. The difference is that in this embodiment, the housing 10 includes two top covers 1, and the positive terminal 3 and the negative terminal 4 are respectively disposed on the two top covers 1 (that is, the two top covers 1 in this embodiment are both shell bodies of the housing 10).

[0121] like Figure 11 and Figure 12 As shown, the side shell 2 of the housing 10 has two openings 21 extending through both sides, and the two top covers 1 respectively close the openings 21 on both sides of the side shell 2 to form a space for accommodating the electrode assembly 20. Figure 11 As shown, the positive terminal 3 is disposed on a top cover 1, and its structural arrangement is the same as that in Embodiment 1. Figure 12 As shown, the negative terminal 4 is disposed on another top cover 1, and its structural arrangement is the same as that in Embodiment 1, so that the top cover 1 is negatively charged.

[0122] Example 3

[0123] This embodiment provides a housing 10 for a battery cell 100, whose structure is largely the same as that of the housing 10 provided in Embodiment 1. The difference is that in this embodiment, the housing 10 includes a top cover 1 and a side cover 2. One end of the side cover 2 is open to form an opening 21, and the other end is closed. The top cover 1 closes the opening 21 of the side cover 2 to form a space for accommodating the electrode assembly 20. The positive terminal 3 is disposed on the side cover 2, and the negative terminal 4 is disposed on the top cover 1 (that is, in this embodiment, both the side cover 2 and the top cover 1 are the shell body of the housing 10). By leading the negative electrode tab 202 of the electrode assembly 20 outward through the second side b of the top cover 1, the second terminal layer 42 of the negative terminal 4, and the first terminal layer 41, the top cover 1 becomes negatively charged.

[0124] Example 4

[0125] This embodiment provides a housing 10 for a battery cell 100, whose structure is largely the same as that of the housing 10 provided in Embodiment 1. The difference is that in this embodiment, the housing 10 includes a top cover 1 and a side shell 2. One end of the side shell 2 is open to form an opening 21, and the other end is closed. The top cover 1 closes the opening 21 of the side shell 2 to form a space for accommodating the electrode assembly 20. The positive terminal 3 is disposed on the top cover 1, while the negative terminal 4 is disposed on the side shell 2 (that is, in this embodiment, both the side shell 2 and the top cover 1 are the shell body of the housing 10). Therefore, in this embodiment, the negative electrode tab 202 of the electrode assembly 20 is led outward through the side shell 2, the second terminal layer 42 of the negative terminal 4, and the first terminal layer 41, so that the side shell 2 is negatively charged.

[0126] Example 5

[0127] This embodiment provides a housing 10 for a battery cell 100, whose structure is largely the same as that of the housing 10 provided in Embodiment 1. The difference is that in this embodiment, the housing 10 includes a top cover 1 and a side shell 2. One end of the side shell 2 is open to form an opening 21, and the other end is closed. The top cover 1 closes the opening 21 of the side shell 2 to form a space for accommodating the electrode assembly 20. The positive terminal 3 and the negative terminal 4 are both disposed on the side shell (i.e., in this embodiment, the side shell 2 is the shell body of the housing 10). Therefore, in this embodiment, the negative electrode tab 202 of the electrode assembly 20 is led outward through the side shell 2, the second terminal layer 42 of the negative terminal 4, and the first terminal layer 41, so that the side shell 2 is negatively charged.

[0128] Of course, in other embodiments, the positive terminal 3 and the negative terminal 4 can be set on any part of the housing 10, such as the top cover 1 or the side shell 2, as needed, so that the positive electrode tab 201 of the electrode assembly 20 is led outward through the positive terminal 3 which is insulated from the housing 10, and the negative electrode tab 202 is led outward sequentially through the housing 10 and the negative terminal 4. The specific setting position of the positive terminal 3 and the negative terminal 4 can be set according to the actual design requirements.

[0129] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A housing for a battery cell, characterized in that, It includes: The shell body has a through hole. The shell body is made of steel. The thickness direction of the shell body is a first direction. In the first direction, the shell body includes a first side and a second side opposite to each other. The positive terminal passes through the through hole; An upper insulating element is disposed between the positive terminal and the housing body to insulate the positive terminal from the housing body; The negative terminal includes a first terminal layer and a second terminal layer disposed along the first direction. The first terminal layer and the second terminal layer are electrically connected, and the second terminal layer is electrically connected to the first side. The material of the second terminal layer is steel, and the material of the first terminal layer is different from that of the second terminal layer.

2. The housing of the battery cell as described in claim 1, characterized in that, The first side has a recessed portion that is recessed toward the second side, and at least a portion of the second terminal layer is accommodated within the recessed portion.

3. The housing of the battery cell as described in claim 2, characterized in that, The depth of the recess is greater than or equal to half the thickness of the shell body.

4. The housing of the battery cell as described in claim 2, characterized in that, The depth of the recess is D, where 0.8mm ≤ D ≤ 2mm.

5. The housing of the battery cell as described in claim 2, characterized in that, The second side has a protrusion corresponding to the position of the recess.

6. The housing of the battery cell as described in claim 5, characterized in that, Both the positive and negative terminals are located on the first side of the shell body, and on the second side, the protrusion is at the same height as the positive terminal.

7. The housing of the battery cell as described in claim 2, characterized in that, There is a gap between the inner peripheral side of the recess and the outer peripheral side of the second terminal layer, and the size of the gap is M, 0.1mm≤M≤0.2mm.

8. The housing of the battery cell as described in claim 2, characterized in that, On the first side, the surface of the second terminal layer is flush with the surface of the shell body; and / or, On the first side, the surface of the first terminal layer protrudes from the surface of the shell body.

9. The housing of the battery cell as described in claim 1, characterized in that, Along the first direction, the projection of the first terminal layer onto the surface of the second terminal layer lies within the range of the second terminal layer.

10. The housing of the battery cell as described in claim 9, characterized in that, Along the first direction, the area of ​​the projection of the second terminal layer that is not covered by the projection of the first terminal layer is an annular area set along the edge of the projection of the second terminal layer.

11. The housing of the battery cell as described in claim 10, characterized in that, The minimum width of the annular region is Nmin, where Nmin ≥ 0.4 mm; And / or, the maximum width of the annular region is Nmax, where Nmax ≤ 0.8 mm.

12. The housing of the battery cell as described in claim 1, characterized in that, The housing also includes an annular seal fixed between the second terminal layer and the first side of the housing body.

13. The housing of the battery cell as described in claim 12, characterized in that, The welding area between the second terminal layer and the shell body is located on the outside of the annular seal.

14. The housing of the battery cell as described in claim 13, characterized in that, The second terminal layer has a sealing groove on the surface facing the first side and / or the first side also has a sealing groove to accommodate the annular seal.

15. The casing of the battery cell as described in any one of claims 1-14, characterized in that, In a second direction perpendicular to the first direction, one of the upper insulating member and the shell body has an outwardly protruding positioning portion, and the other has a receiving portion that mates with the positioning portion.

16. The casing of the battery cell as described in any one of claims 1-14, characterized in that, The shell body includes a top cover and side shells. The top cover and the opening of the side shells are electrically connected and together form an accommodating space.

17. The casing of the battery cell as described in any one of claims 1-14, characterized in that, Both the shell body and the second terminal layer are made of 304 stainless steel; and / or, In the first direction, the negative terminal is rectangular in shape, and rounded corners are provided at the four corners of the negative terminal; and / or, On the first side, the positive terminal is at the same height as the first terminal layer; and / or, The thickness of the second terminal layer is T1, 0.6mm ≤ T1 ≤ 1mm; and / or, The thickness of the first terminal layer is T2, 0.6mm ≤ T2 ≤ 1mm; and / or, The thickness of the shell body is T3, where 0.8mm ≤ T3 ≤ 1.2mm.

18. A battery cell, characterized in that, It includes: The housing of the battery cell as described in any one of claims 1-17.

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