Battery cell casing and cover plate engagement structure, battery cell, and battery pack

Abstract

A battery cell casing (1) and cover plate (2) engagement structure, a battery cell, and a battery pack. Said engagement structure comprises an opening (11) formed in a battery cell casing (1). A cover plate (2) is provided with a boss (21), the root of the boss (21) being provided with a lap joint portion (22); the boss (21) extends into the battery cell casing (1) via the opening (11); the lap joint portion (22) overlaps the battery cell casing (1); the boss (21) is in near-zero-clearance fit with the opening (11); an outer end face of the lap joint portion (22) is flush with an outer side face of the battery cell casing (1); and the cover plate (2) is welded to the battery cell casing (1). The ratio K1 of the thickness L2 of the lap joint portion (22) to the thickness L1 of the cover plate (2) satisfies: 16.7%≤ K1≤ 80%; and the ratio K2 of the thickness Ln of the boss (21) to the thickness L1 of the cover plate (2) satisfies: 20%≤K2≤83.3%, and satisfies: K1+ K2=1. Said engagement structure can improve the fitting degree of the battery cell casing (1) and the cover plate (2), and can improve the welding strength and welding yield between the battery cell casing (1) and the cover plate (2), thereby ensuring post-welding sealing performance.

Description

Battery cell shell and cover matching structure, battery cell and battery pack

[0001] This disclosure claims priority to a patent application filed with the Patent Office of China on December 4, 2023, with application number 202311656248.9 and titled “Battery Cell Shell and Cover Matching Structure and Battery Cell,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of lithium battery technology, and more particularly to a cell housing and cover plate matching structure. The present disclosure also relates to a cell equipped with the cell housing and cover plate matching structure. The present disclosure also relates to a battery pack equipped with the cell. Background Art

[0003] Lithium-ion power batteries generally consist of an internal structure and an external structure. The internal structure primarily consists of the cell electrode group, while the external structure primarily consists of the cell cover and cell casing. The cell casing provides space for the cell electrode group. The cell cover and cell casing are welded together to form an enclosed space, thereby forming the complete lithium-ion battery structure.

[0004] In blade lithium-ion batteries, the cell housing is typically formed using high-frequency welding and laser welding processes. The housing features openings on both sides, facilitating welding with the cell cover. In existing technology, the cell electrode assembly is first installed inside the cell housing. The opening is then sealed with the cell cover, which is then slot-welded with a laser to seal the cell cover to the cell housing.

[0005] However, the above-mentioned sealing welding method does not restrict the matching size and structure of the battery cell shell and the cover plate, which leads to the welding connection between the battery cell cover plate and the battery cell shell being not strong enough, the welding yield is low, and the welding gap between the battery cell cover plate and the battery cell shell is prone to cracking and damage, which increases production costs and reduces production efficiency; especially when the battery generates gas during the charging and discharging process, the internal air pressure will form shear force at the welding gap, and the weld is prone to cracking. Its poor sealing leads to battery leakage, resulting in battery failure, and even serious safety accidents. Summary of the Invention

[0006] In view of this, the present disclosure aims to provide a matching structure of a battery cell housing and a cover plate, so as to improve the welding strength and welding yield rate between the battery cell housing and the cover plate.

[0007] To achieve the above objectives, the technical solution of the present disclosure is implemented as follows:

[0008] A cell shell and cover plate matching structure includes an opening formed on the cell shell;

[0009] The cover plate is provided with a boss protruding toward one side of the battery cell shell, and a lap joint is formed at the root of the boss; the boss extends from the opening into the battery cell shell, the lap joint overlaps the battery cell shell, the length and width of the boss are respectively set to correspond to the length and width of the opening, the outer end surface of the lap joint is flush with the outer side surface of the battery cell shell, and the cover plate is welded to the battery cell shell;

[0010] When the cover plate and the battery cell shell are assembled, the ratio K1 of the thickness L2 of the overlapping portion to the thickness L1 of the cover plate satisfies: K1=L2 / L1, 16.7%≤K1≤80%, the ratio K2 of the thickness Ln of the boss to the thickness L1 of the cover plate satisfies: K2=Ln / L1, 20%≤K2≤83.3%, and satisfies: K1+K2=1.

[0011] Furthermore, the thickness L1 of the cover plate satisfies: 1.5 mm ≤ L1 ≤ 3 mm.

[0012] Furthermore, the thickness L2 of the overlapping portion satisfies: 0.5 mm ≤ L2 ≤ 2.4 mm.

[0013] Furthermore, the thickness Ln of the boss satisfies: 0.6 mm ≤ Ln ≤ 2.5 mm.

[0014] Furthermore, the wall thickness h of the battery cell shell satisfies: 0.2 mm ≤ h ≤ 3 mm.

[0015] Furthermore, a guide inserting portion is provided on the boss.

[0016] Furthermore, the guide insert portion includes a chamfer formed on the end of the boss.

[0017] Furthermore, a distance L4 of the chamfer in the direction in which the boss extends into the battery cell housing is between 0.1 mm and 2 mm.

[0018] Furthermore, along the direction in which the boss extends into the cell housing, a ratio K3 of a size L3 of a contact portion between the boss and the cell housing and a thickness L1 of the cover plate satisfies: K3=L3 / L1, 16.7%≤K3≤80%.

[0019] Furthermore, a ratio K4 of the total value of the thickness L2 of the overlap portion and the dimension L3 of the contact portion between the boss and the cell housing to the thickness L1 of the cover plate satisfies: K4=(L2+L3) / L1, 33.3%≤K4≤96.7%.

[0020] Furthermore, a dimension L3 of the contact portion between the boss and the cell housing satisfies: 0.5 mm ≤ L3 ≤ 2.4 mm.

[0021] Compared with the prior art, the present disclosure has the following advantages:

[0022] The cell shell and cover plate matching structure disclosed in the present invention is a matching form in which the boss and the overlap portion are arranged on the cover plate, and the gap between the boss and the opening is close to zero. The overlap portion overlaps the end of the cell shell, and the outer end surface of the overlap portion is arranged flush with the outer side surface of the cell shell. At the same time, by setting the ratios K1 and K2 of the thickness of the overlap portion and the thickness of the boss to the thickness of the cover plate respectively, the matching degree of the cell shell and the cover plate can be improved, thereby improving the welding strength and welding yield between the cell shell and the cover plate, and further ensuring the sealing performance after welding.

[0023] Furthermore, setting the cover plate thickness between 1.5mm and 3mm balances low cost and high welding quality, avoiding the increased weight and structural cost of a thicker cover plate, as well as the increased welding difficulty and cracking caused by a thinner cover plate. Setting the overlap thickness between 0.6mm and 2.5mm avoids compromising weld strength due to smaller dimensions. The boss thickness ensures butt welding between the cell housing and the cover plate, ensuring a post-weld seal.

[0024] In addition, the guide plug-in portion on the boss can facilitate the boss to extend into the battery cell shell, which is convenient for the assembly of the cover plate and the battery cell shell. The guide plug-in portion adopts chamfering, which has the characteristics of simple structure, easy processing and manufacturing, and low cost. The setting of the ratio K3 and the ratio K4 can help to ensure the welding quality of the butt weld between the battery cell shell and the cover plate, and avoid the problem of unqualified welding quality due to too small size and waste caused by too large size. In the structure with the guide plug-in portion, the size of the contact part between the boss and the battery cell shell is between 0.5mm and 2.4mm, which can further ensure the quality of the butt weld between the battery cell shell and the cover plate, and can improve the yield rate of one-time welding.

[0025] Another object of the present disclosure is to provide a battery cell, in which the battery cell housing and cover plate matching structure as described above is provided.

[0026] Furthermore, a positive electrode cover plate and a negative electrode cover plate are respectively provided at both ends of the battery cell shell in the battery cell; the positive electrode cover plate and the battery cell shell are connected by the battery cell shell and cover plate matching structure.

[0027] Furthermore, a positive electrode cover plate and a negative electrode cover plate are respectively provided at both ends of the cell shell in the battery cell; the negative electrode cover plate and the cell shell are connected by the cell shell and cover plate matching structure.

[0028] The battery cell disclosed herein can improve the welding strength between the battery cell shell and the cover plate by adopting the above-mentioned battery cell shell and cover plate matching structure, and can also improve the welding yield rate between the battery cell shell and the cover plate, and has a good use effect.

[0029] Another object of the present disclosure is to provide a battery pack, in which the battery cell as described above is provided.

[0030] The battery pack disclosed herein, by adopting the above-mentioned battery cells, can improve the welding strength between the battery cell shell 1 and the cover plate 2, and can also improve the welding yield rate of the battery cell shell 1 and the cover plate 2, thereby helping to improve the quality and performance of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute part of this disclosure, are used to provide a further understanding of the disclosure. The exemplary embodiments of the disclosure and their descriptions are used to explain the disclosure and do not constitute an improper limitation of the disclosure. In the accompanying drawings:

[0032] FIG1 is a schematic structural diagram of the matching structure of a cell housing and a cover plate according to an embodiment of the present disclosure;

[0033] FIG2 is a schematic structural diagram of a cover plate according to an embodiment of the present disclosure;

[0034] FIG3 is a partial enlarged view of a battery cell casing according to an embodiment of the present disclosure;

[0035] FIG4 is a schematic structural diagram of a battery cell according to an embodiment of the present disclosure;

[0036] FIG5 is an enlarged view of the metallographic structure of the weld position after welding the battery cell housing of the embodiment of the present disclosure to a cover plate of another structural form (the left image is a defective product, and the right image is a qualified product);

[0037] Description of reference numerals:

[0038] 1. Battery cell housing; 11. Opening;

[0039] 2. Cover plate; 21. Boss; 22. Overlap; 211. Chamfer;

[0040] 3. Battery cell group. DETAILED DESCRIPTION

[0041] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

[0042] In the description of this disclosure, it should be noted that if terms such as "upper," "lower," "inner," and "outer" appear to indicate orientation or positional relationships, these are based on the orientation or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this disclosure and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this disclosure. Furthermore, if terms such as "first" and "second" appear, they are used solely for descriptive purposes and should not be construed as indicating or implying relative importance.

[0043] Furthermore, in the description of this disclosure, unless otherwise explicitly defined, the terms "mounted," "connected," "connect," and "connector" should be interpreted broadly. For example, these terms can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will appreciate the specific meanings of these terms in this disclosure based on the specific circumstances.

[0044] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Example 1

[0045] The embodiments of the present disclosure relate to a cell housing and cover plate matching structure, which can improve the welding strength and welding yield between the cell housing 1 and the cover plate 2.

[0046] In terms of overall structure, the cell housing and cover plate cooperation structure of this embodiment, as shown in FIG1 , includes an opening 11 formed on the cell housing 1 , and a cover plate 2 sealing the opening 11 . In addition, the cover plate 2 is provided with a boss 21 protruding toward one side of the battery cell shell, and a lap joint 22 is formed at the root of the boss 21; the boss 21 extends from the opening 11 into the battery cell shell 1, and the lap joint 22 overlaps the battery cell shell 1. The length and width of the boss 21 are respectively set to correspond to the length and width of the opening 11, and the outer end surface of the lap joint 22 is flush with the outer side surface of the battery cell shell 1, and the cover plate 2 is welded to the battery cell shell 1. In addition, when the cover plate and the battery cell shell are assembled, the ratio K1 of the thickness L2 of the lap joint to the thickness L1 of the cover plate satisfies: K1=L2 / L1, 16.7%≤K1≤80%, the ratio K2 of the thickness Ln of the boss to the thickness L1 of the cover plate satisfies: K3=Ln / L1, 20%≤K2≤83.3%, and satisfies: K1+K2=1.

[0047] At this time, the boss 21 extending into the battery cell shell 1 is matched with the opening 11 to be close to zero clearance, and the overlapping portion 22 is overlapped on the end of the battery cell shell 1, and the outer end surface of the overlapping portion is flush with the outer side surface of the battery cell shell. At the same time, by setting the ratios K1 and K2 of the thickness of the overlapping portion and the thickness of the boss to the thickness of the cover plate respectively, the fit between the battery cell shell 1 and the cover plate 2 can be improved, thereby improving the welding strength between the battery cell shell 1 and the cover plate 2, and also improving the welding yield rate of the battery cell shell 1 and the cover plate 2, thereby ensuring the sealing performance after welding.

[0048] Specifically, the cell housing 1 is a rectangular parallelepiped structure with a hollow interior forming a cavity for accommodating the cell electrode group 3. An opening 11 is provided at the top of the cell housing 1, or for the cell housing 1 of a blade battery, openings 11 are formed on two opposite sides thereof. The openings are rectangular, and the cover 2 is welded to the cell housing 1 to seal the openings 11.

[0049] In this embodiment, as shown in Figures 1 and 2, the cover plate 2 is provided with a boss 21 protruding toward one side thereof, and a lap joint 22 is formed at the base of the boss 21. The lap joint 22 overlaps the overlapped surface of the end of the cell housing 1, forming a step-like shape with the boss 21. In the assembled state, the boss 21 extends into the cell housing 1 through the opening 11, and the length of the boss 21 is approximately equal to the length of the opening 11, and the width of the boss 21 is approximately equal to the width of the opening 11. This allows the boss 21 to be effectively sealed at the opening 11 and provide a certain degree of support for the sidewalls of the cell housing 1, thereby improving the fit between the cell housing 1 and the cover plate 2, and enhancing the weld strength and weld yield rate. The lap joint 22 overlaps the cell housing 1, and the outer end surface of the lap joint 22 is flush with the outer side surface of the cell housing 1, which ensures a consistent appearance and also helps ensure sealing performance after welding.

[0050] It is worth noting that the length dimensions of the boss 21 and the opening 11 should be as equal as possible, and the width dimensions should also be as equal as possible. Due to processing errors during the manufacturing process, the tolerance range of the length and width dimensions of the opening 11 is ±0.1mm, and the tolerance range of the length and width dimensions of the boss 21 is ±0.05mm. In addition, it is also worth noting that a, b, A, and B in Figure 1 respectively indicate the width of the overlap portion 22, the width of the boss 21, the outer width of the battery cell housing 1, and the width of the opening 11.

[0051] In this embodiment, when the cover plate and the cell housing are assembled, the ratio K1 of the thickness L2 of the overlap portion to the thickness L1 of the cover plate satisfies the following conditions: K1 = L2 / L1, 16.7% ≤ K1 ≤ 80%. The ratio K2 of the thickness Ln of the boss to the thickness L1 of the cover plate satisfies the following conditions: K2 = Ln / L1, 20% ≤ K2 ≤ 83.3%, and K1 + K2 = 1. This arrangement helps reduce manufacturing costs while ensuring good welding quality.

[0052] As a preferred embodiment, in this example, the thickness L1 of the cover plate 2 satisfies the following conditions: 1.5 mm ≤ L1 ≤ 3 mm. This achieves a balance between low cost and high welding quality, avoiding the increased weight and structural cost of a thicker cover plate 2, as well as the increased welding difficulty and weld cracking caused by a thinner cover plate 2. In specific implementations, the thickness of the cover plate 2 can be set to, for example, 1.5 mm, 2.0 mm, 2.5 mm, or 3 mm, with 2 mm being the preferred setting.

[0053] Furthermore, in this embodiment, the thickness L2 of the overlapping portion 22 satisfies the following condition: 0.5 mm ≤ L2 ≤ 2.4 mm. Setting the thickness of the overlapping portion 22 can prevent the weld strength from being affected by its small size. In practice, the thickness of the overlapping portion 22 can be set to, for example, 0.5 mm, 0.75 mm, 0.95 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.75 mm, 1.95 mm, 2.15 mm, 2.25 mm, or 2.4 mm, and is preferably set to 0.75 mm.

[0054] In this embodiment, the thickness of the boss 21 satisfies the following conditions: 0.6mm ≤ Ln ≤ 2.5mm. This ensures the butt welding of the cell housing 1 and the cover plate 2, ensuring a seal after welding. In practice, the thickness of the boss 21 can be, for example, 0.6mm, 0.75mm, 0.95mm, 1.1mm, 1.3mm, 1.5mm, 1.75mm, 1.95mm, 2.15mm, 2.25mm, or 2.5mm.

[0055] As shown in Figures 1 and 3 , the wall thickness h of the cell casing 1 of this embodiment satisfies the following conditions: 0.2 mm ≤ h ≤ 3 mm. This ensures that the cell casing 1 has good structural strength and low manufacturing costs. In practice, the thickness h of the cell casing 1 can be set to values ​​such as 0.2 mm, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, or 3 mm (the casing thickness does not affect the post-weld welding effect). This is not specifically limited here.

[0056] As a preferred embodiment, in this embodiment, a guide insertion portion is provided on the boss 21. This guide insertion portion facilitates insertion of the boss 21 into the cell housing 1, facilitating assembly of the cover plate 2 and the cell housing 1. Specifically, as shown in Figures 1 and 2, the guide insertion portion includes a chamfer 211 formed on the end of the boss 21. The chamfer 211 in the guide insertion portion exhibits a simple structure, ease of fabrication, and low cost.

[0057] In this embodiment, a chamfer 211 is provided at the end of the boss 21. In this case, along the direction in which the boss 21 extends into the cell housing 1, the ratio K3 of the dimension L3 of the contact portion between the boss and the cell housing to the thickness L1 of the cover plate satisfies the following conditions: K3 = L3 / L1, with 16.7% ≤ K3 ≤ 80%. Furthermore, the ratio K4 of the combined thickness L2 of the overlap portion and the dimension L3 of the contact portion between the boss and the cell housing to the thickness L1 of the cover plate satisfies the following conditions: K4 = (L2 + L3) / L1, with 33.3% ≤ K4 ≤ 96.7%. These ratios K3 and K4 help ensure the quality of the butt weld between the cell housing and the cover plate, avoiding issues such as substandard welding due to undersize and waste due to oversize.

[0058] In specific implementations, the dimension L3 of the contact portion between the boss 21 and the cell housing 1 satisfies the following: 0.5mm ≤ L3 ≤ 2.4mm. Preferably, L3 is 0.95mm. This ensures smooth assembly of the boss 21 into the opening 11, further improves the quality of the butt weld between the cell housing 1 and the cover plate 2, and improves the yield rate of a single weld. In this case, the distance L4 of the chamfer 211 in the direction in which the boss 21 extends into the cell housing 1 is between 0.1mm and 2mm, and preferably 0.3mm.

[0059] In this embodiment, during the assembly and welding of the cell housing and the cover plate, the cover plate and the periphery of the cell housing are pre-spot welded prior to the welding process. This allows the cover plate to be pre-fixed to the cell housing, and the pre-welded spots cover the gap formed by the fit between the cover plate and the cell housing. Furthermore, the assembly gap between the cover plate and the cell housing is maintained within 0.15 mm. (A gap greater than 0.15 mm, i.e., a larger gap, results in poor laser pre-spot welding, resulting in low weld strength and a compressive strength below 1.2 MPa after laser periphery welding.) This gap ensures the effectiveness of the pre-spot welding, and thus ensures the post-weld strength of the periphery weld between the cell housing and the cell cover plate. The weld strength, i.e., the compressive strength, is greater than 1.2 MPa, and the helium leak rate of the battery after periphery welding is less than 1*10-7 Pa*m3 / s.

[0060] The following examples and comparative examples in Tables 1 and 2 demonstrate that the disclosed cell housing and cover plate matching structure can improve welding quality and airtightness. The cell housings 1 are of the same dimensions and are then assembled with covers of different dimensions (different L1, L2, L3, and L4) and then laser welded. The specific dimensions are shown in Tables 1 and 2:

[0061] Table 1

[0062]

[0063] Table 2

[0064]

[0065] The data in the table above shows that, compared with covers 2#, 4#, and 5#, all with a thickness of 1.5mm, the following results are obtained after welding to the shell: Cover L3 of cover 4# is 0.45mm, and cover L2 of cover 5# is 0.45mm, both of which are smaller. After laser welding, weld beads appear at the weld (L3 is small, and the beads are formed by the melting of the laser welding process). The shell strength, or compressive strength, after welding is lower than 1.2 MPa, even lower than 1.0 MPa. The helium leak rate after welding is higher than 1*10-7 Pa*m3 / s. Comparing covers 5#, 11#, and 12#, each with a smaller L2 of 0.45mm, weld beads appear at the weld, and the weld strength and helium leak rate do not meet the requirements.

[0066] Comparing 1#, 6#, and 7#, the cover thickness is all 2mm, and the effects after welding with the shell are as follows: the L3 size of the 7# cover is 0.45mm, which is smaller. Weld beads appear at the same welding position, and the welding strength and helium leak detection rate do not meet the requirements.

[0067] Comparing the 3#, 8#, 9#, and 10# cover plates, which all have a thickness of 3mm, the effects after welding with the shell are as follows: the L3 size of the 8# cover plate is 0.45mm, which is smaller. Weld beads appear at the welding position, and the welding strength and helium leak rate do not meet the requirements. The L3 size of the 10# cover plate is 0.5mm. No weld beads appear at the laser butt welding position, and the overall welding airtightness is good.

[0068] After laser welding the cover plates 2 of cells 1#, 2#, and 3# to the cell housing 1, no weld beads appeared at the seam welds, indicating good overall weld tightness. However, after laser welding the cover plate 4#, weld beads appeared at the welds, indicating poor overall weld tightness.

[0069] Referring to Figure 5, the left image shows a magnified view of the metallographic structure of the weld seam after welding the cell housing to a cover plate of another structural type, while the right image shows a magnified view of the metallographic structure of the weld seam after welding the cell housing to the cover plate of this embodiment. Comparing the left and right images in Figure 5 shows that weld beads appear after welding in the left image, indicating unacceptable weld quality, while weld beads do not appear in the right image, indicating good weld quality.

[0070] The above analysis shows that the L2 and L3 dimensions of the cover plate must be greater than 0.5mm. In the design, L2 is 0.75mm and L3 is 0.65mm to meet welding requirements. L4 can be set to be greater than 0.1mm (refer to the cover plate thickness setting). The minimum cover plate thickness can be 0.75mm + 0.65mm + 0.1mm = 1.5mm. Considering that the cover plate thickness affects the cover plate strength, the industry generally uses 2.0mm (which meets welding standards). Using a 3mm thick cover plate can better meet welding strength and sealing requirements, but it will increase material costs. Therefore, 1# cover plate 2 is the preferred matching size.

[0071] The cell housing and cover plate matching structure of this embodiment can increase the matching degree between the cell housing 1 and the cover plate 2 by constraining and limiting the matching dimensions of the cover plate 2 and the cell housing 1, improve the welding yield of the cell housing 1 and the cell cover plate 2, and also reduce material costs and improve production efficiency. Example 2

[0072] The embodiments of the present disclosure also relate to a battery cell, in which the battery cell shell and cover plate matching structure described in the first embodiment is provided.

[0073] As shown in Figure 4, in the battery cell of this embodiment, a positive electrode cover plate and a negative electrode cover plate are respectively provided at both ends of the battery cell housing 1. The positive electrode cover plate and the negative electrode cover plate are respectively welded to the ends of the battery cell housing 1. The battery cell housing and cover plate matching structure of the first embodiment is used to connect the positive electrode cover plate and the battery cell housing 1, and the negative electrode cover plate and the battery cell housing 1. That is, a boss 21 and a lap joint 22 are provided on each of the positive electrode cover plate 2 and the negative electrode cover plate 2. The boss 21 and lap joint 22 on the positive electrode cover plate 2, as well as the boss 21 and lap joint 22 on the negative electrode cover plate 2, respectively mate with the openings 11 at both ends of the battery cell housing 1.

[0074] It can be understood here that in addition to using the battery shell and cover plate matching structure of Example 1 to connect the positive cover plate and the battery cell shell 1, and between the negative cover plate and the battery cell shell 1, it is also possible to use the battery shell and cover plate matching structure of Example 1 only between the positive cover plate and the battery cell shell 1, or use the battery shell and cover plate matching structure of Example 1 only between the negative cover plate and the battery cell shell 1.

[0075] The battery cell of this embodiment, by adopting the battery cell shell and cover plate matching structure of Example 1, can improve the welding strength between the battery cell shell 1 and the cover plate 2, and can also improve the welding yield of the battery cell shell 1 and the cover plate 2, and has a good use effect. Example 3

[0076] The embodiments of the present disclosure also relate to a battery pack, which is provided with the battery cell of embodiment 2. In a specific implementation, multiple battery cells are stacked to form a battery module, which is housed in a housing of the battery pack.

[0077] The battery pack of this embodiment, by adopting the battery cell of the second embodiment, can improve the welding strength between the battery cell shell 1 and the cover plate 2, and can also improve the welding yield rate of the battery cell shell 1 and the cover plate 2, thereby helping to improve the quality and performance of the battery pack.

[0078] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A cell housing and cover plate matching structure, characterized in that: comprising an opening (11) formed on the battery cell housing (1); The cover plate (2) is provided with a boss (21) protruding toward one side of the battery cell shell (1), and a lap joint (22) is formed at the root of the boss (21); the boss (21) extends from the opening (11) into the battery cell shell (1), the lap joint (22) overlaps the battery cell shell (1), the length and width of the boss (21) are respectively arranged to correspond to the length and width of the opening (11), the outer end surface of the lap joint (22) is arranged flush with the outer side surface of the battery cell shell (1), and the cover plate (2) is welded to the battery cell shell (1); When the cover plate (2) and the cell housing (1) are in an assembled state, a ratio K1 of a thickness L2 of the overlap portion (22) to a thickness L1 of the cover plate (2) satisfies: K1=L2 / L1, 16.7%≤K1≤80%, a ratio K2 of a thickness Ln of the boss (21) to a thickness L1 of the cover plate (2) satisfies: K2=Ln / L1, 20%≤K2≤83.3%, and K1+K2=1.

2. The battery cell housing and cover plate matching structure according to claim 1, characterized in that: The thickness L1 of the cover plate (2) satisfies: 1.5 mm ≤ L1 ≤ 3 mm.

3. The battery cell housing and cover plate matching structure according to claim 1, characterized in that: The thickness L2 of the overlapping portion (22) satisfies: 0.5 mm ≤ L2 ≤ 2.4 mm.

4. The battery cell housing and cover plate matching structure according to claim 1, characterized in that: The thickness Ln of the boss (21) satisfies: 0.6 mm ≤ Ln ≤ 2.5 mm.

5. The battery cell housing and cover plate matching structure according to claim 1, characterized in that: The wall thickness h of the battery cell housing (1) satisfies: 0.2 mm ≤ h ≤ 3 mm.

6. The battery cell housing and cover plate matching structure according to any one of claims 1 to 5, characterized in that: The boss (21) is provided with a guide insertion portion.

7. The battery cell housing and cover plate matching structure according to claim 6, characterized in that: The guide insertion portion comprises a chamfer (211) formed on the end of the boss (21).

8. The battery cell housing and cover plate matching structure according to claim 7, characterized in that: The distance L4 of the chamfer (211) in the direction in which the boss (21) extends into the battery cell housing (1) is between 0.1 mm and 2 mm.

9. The battery cell housing and cover plate matching structure according to claim 7, characterized in that: Along the direction in which the boss (21) extends into the battery cell housing (1), a ratio K3 of a size L3 of a contact portion of the boss (21) with the battery cell housing (1) to a thickness L1 of the cover plate (2) satisfies: K3=L3 / L1, 16.7%≤K3≤80%.

10. The battery cell housing and cover plate matching structure according to claim 9, characterized in that: A ratio K4 of the total value of the thickness L2 of the overlapped portion (22) and the dimension L3 of the contact portion of the boss (21) with the battery cell housing (1) to the thickness L1 of the cover plate (2) satisfies: K4=(L2+L3) / L1, 33.3%≤K4≤96.7%.

11. The battery cell housing and cover plate matching structure according to claim 9, characterized in that: The dimension L3 of the contact portion between the boss (21) and the battery cell housing (1) satisfies the following: 0.5 mm ≤ L3 ≤ 2.4 mm.

12. A battery cell, characterized in that: The battery cell is provided with a battery cell housing and cover plate matching structure according to any one of claims 1 to 11.

13. The battery cell according to claim 12, characterized in that: The battery cell shell (1) in the battery cell is provided with a positive electrode cover plate and a negative electrode cover plate at both ends thereof respectively; The positive electrode cover plate and the battery cell shell (1) are connected by using the battery cell shell and cover plate matching structure.

14. The battery cell according to claim 12, characterized in that: The battery cell shell (1) in the battery cell is provided with a positive electrode cover plate and a negative electrode cover plate at both ends thereof respectively; The negative electrode cover plate and the battery cell shell (1) are connected by using the battery cell shell and cover plate matching structure.

15. A battery pack, characterized in that: The battery pack is provided with the battery cell according to any one of claims 12 to 14.

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