Battery module case and battery module containing the same

Abstract

The battery module case according to the embodiment of the present invention has a stepped structure to improve welding defects, thereby increasing the bonding strength between the components of the case and improving the yield of the battery module.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0065689 filed on May 27, 2022 and Korean Patent Application No. 10-2023-0062507 filed on May 15, 2023, and all the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference in their entirety.

[0002] The present invention relates to a battery module case and a battery module including the same.

Background Art

[0003] Generally, types of secondary batteries include nickel cadmium batteries, nickel metal hydride batteries, lithium ion batteries, and lithium ion polymer batteries. Such secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, and electric bicycles, but also in large products that require high power such as electric vehicles and hybrid vehicles, as well as in power storage devices for storing surplus generated power and new / renewable energy, and backup power storage devices.

[0004] To manufacture such secondary batteries, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, and these are laminated on both sides of a separator to form an electrode assembly having a predetermined shape. Also, the electrode assembly is housed in a battery case, electrolyte is injected, and then sealed.

[0005] In this way, a battery cell is manufactured by housing an electrode assembly in a battery case and injecting an electrolyte. Multiple battery cells are then housed in a frame-type case, while connected to each other, to protect them from external shocks, heat, and vibrations. This completes the production of a battery module, and subsequently, a control system such as a BMS (Battery Management System) is added to the battery module to complete the battery pack.

[0006] During the process of housing battery cells in a battery module case and welding the battery module case, welding defects can occur, resulting in a low battery module yield. Therefore, there is a need for a battery module case with a structure that facilitates welding and increases the strength of the welded joint. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] One problem that this invention aims to solve is to provide a battery module case that improves welding defects. [Means for solving the problem]

[0008] A battery module case according to an embodiment of the present invention includes a main body including a bottom plate and a pair of side plates connected to both sides of the bottom plate; an end plate that covers the front and rear surfaces of the main body located in front of and behind the longitudinal direction of the bottom plate and is connected to the main body; and a cover plate that covers one surface of the main body parallel to the longitudinal direction of the bottom plate and is connected to the main body, wherein one side of the bottom plate connected to the end plate can be formed in a stepped shape.

[0009] The bottom plate may include a main body portion and stepped portions formed in a stepped manner at both ends of the main body portion.

[0010] The end plate can be coupled and connected to the stepped portion.

[0011] The end plate may include a joint portion that is recessed to correspond to the shape of the stepped portion.

[0012] Based on the view of the side plate, the connecting portion includes a first surface that is connected to the lower surface of the end plate and perpendicular to the lower surface, and a second surface that is connected to the first surface and perpendicular to the first surface, and the stepped portion connects with the first surface and the second surface, thereby enabling the end plate and the main body to be joined to each other.

[0013] Based on the view of the side plate, the stepped portion is formed in a stepped shape from both sides of the main body portion toward the center of the main body portion, and the front and rear surfaces can be formed via the stepped portion and the side plate.

[0014] The thickness of the stepped portion can be greater than the thickness of the main body portion.

[0015] The thickness of the stepped portion can be 1.2 mm or more. [Effects of the Invention]

[0016] According to a preferred embodiment of the present invention, by improving welding defects, the bonding strength between each component of the case can be increased, thereby improving the yield of the battery module.

[0017] In addition, the present invention may include effects that can be easily predicted by those skilled in the art from the configuration of preferred embodiments. [Brief explanation of the drawing]

[0018] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention to be described later. The present invention should not be construed as being limited only to the matters described in such drawings.

[0019] [Figure 1] It is a perspective view of a battery module case according to an embodiment of the present invention. [Figure 2] It is an exploded view of a battery module case according to an embodiment of the present invention. [Figure 3] It is a perspective view of a main body according to an embodiment of the present invention. [Figure 4] It is a cross-sectional view of the battery module case with respect to the AA' cross-section of FIG. 1.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, referring to the attached drawings, preferred embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be realized in various different forms and is not limited or restricted by the following embodiments.

[0021] In order to clearly explain the present invention, detailed descriptions of parts not related to the explanation or of related known technologies that may obscure the gist of the present invention are omitted. When attaching reference numerals to the components of each drawing in this specification, the same or similar reference numerals are attached to the same or similar components throughout the specification.

[0022] Also, the terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings. The inventors should interpret them in accordance with the meanings and concepts that conform to the technical idea of the present invention in accordance with the principle that they can appropriately define the concept of the terms in order to explain their invention in the best way.

[0023] FIG. 1 is a perspective view of a battery module case 10 according to an embodiment of the present invention.

[0024] Referring to FIG. 1, the battery module case 10 can accommodate a cell assembly described later by forming an accommodation space inside. By accommodating the cell assembly, the battery module case 10 can protect the cell assembly from external environments such as external impacts and heat. Also, the battery module case 10 can be manufactured by accommodating the cell assembly inside in a state where one side is open and assembling and welding the open part. For example, the battery module case 10 can be manufactured by covering and welding the front surface M1 and the rear surface M2 in a hexagonal frame where the front surface M1 and the rear surface M2 are open. In the process of welding the battery module case 10, due to a stepped structure of a part of the battery module case 10, the battery module case 10 can be welded more firmly. Specifically, by adjusting the thickness of each part to be welded, the bonding force between the components of the battery module case 10 can be further increased.

[0025] FIG. 2 is an exploded view of the battery module case 10 according to an embodiment of the present invention.

[0026] Referring to FIG. 2, the battery module case 10 can include a main body 100, an end plate 101, and a cover plate 102.

[0027] The main body 100 can serve as the reference frame when manufacturing the battery module case 10. In other words, the main body 100 is a frame with one side open, forming a housing space, and can be assembled with the end plate 101 and cover plate 102 described later. Specifically, the main body 100 has a longitudinal direction and can include a hexagonal structure with the front M1 and rear M2 open in the longitudinal direction. The main body 100 can also include a structure with one side M3 parallel to the longitudinal direction open. With such a structure, the main body 100 can have a hexagonal shape with three open sides.

[0028] Figure 3 is a perspective view of the main body 100 according to an embodiment of the present invention.

[0029] Referring to Figure 3, the main body 100 may include a bottom plate 1000 and side plates 1001. For example, the bottom plate 1000 can constitute the bottom surface of the main body 100. With the bottom plate 1000 forming the bottom surface of the main body 100, the side plates 1001 can be connected to both sides of the bottom plate 1000. In other words, the side plates 1001 can be connected in pairs to both sides of the bottom plate 1000, with respect to its longitudinal direction. In this case, the side plates 1001 can be connected perpendicularly to the bottom plate 1000. As a result, a front surface M1 and a rear surface M2 can be formed, consisting of one side of the bottom plate 1000 and one side of a pair of side plates 1001.

[0030] The bottom plate 1000 can be formed in a stepped shape in part. For example, the bottom plate 1000 can include a main body portion 1000a and a stepped portion 1000b. The main body portion 1000a is located in the central part of the bottom plate 1000 and can have a plate shape with a constant thickness. The stepped portion 1000b is a portion connected to both ends of the main body portion 1000a and can include a stepped shape. Specifically, the stepped portion 1000b can be connected to both ends of the main body portion 1000a that are connected to the end plate 101, rather than to both ends of the main body portion 1000a that are connected to the side plate 1001. In other words, the stepped portion 1000b can be connected to both ends of the main body portion 1000a that constitute the front M1 and rear M2 described above. That is, the front M1 and rear M2 can be formed via the stepped portion 1000b and the side plate 1001.

[0031] More specifically, with reference to the view of the side plate 1001, the stepped portion 1000b can be formed in a stepped manner from both sides of the main body portion 1000a toward the center of the main body portion 1000a. Furthermore, the thickness of the stepped portion 1000b can be greater than the thickness of the main body portion 1000a. In other words, with reference to the view of the side plate 1001, the bottom plate 1000 can have a structure in which, with the main body portion 1000a positioned in the center, the stepped portions 1000b are formed to protrude upward from both sides of the main body portion 1000a.

[0032] The end plates 101 can be connected to the main body 100 so as to cover the front M1 and rear M2 of the main body 100. In other words, the end plates 101 can be configured in pairs and positioned in front of and behind the main body 100, and can be connected to the main body 100.

[0033] Figure 4 is a cross-sectional view of the battery module case relative to the AA' section in Figure 1.

[0034] Referring to Figure 4, the end plate 101 can be joined and connected to the stepped portion 1000b. Specifically, the end plate 101 may include a recessed connecting portion 1010 that corresponds to the shape of the stepped portion 1000b. For example, with reference to the view of the side plate 1001, the connecting portion 1010 may include a first surface 1010a, a second surface 1010b, and a third surface 1010c.

[0035] The first surface 1010a is connected to the lower surface 101a of the end plate 101 and can be made perpendicular to the lower surface 101a. Similarly, the second surface 1010b is connected to the first surface 1010a and can be made perpendicular to the first surface 1010a. Finally, the third surface 1010c is connected to the second surface 1010b and can be made perpendicular to the second surface 1010b. In this case, with the extension line of the lower surface 101a of the end plate 101 and the extension line of the lower surface of the stepped portion 1000b coincide, the stepped portion 1000b is inserted toward the first surface 1010a and joined to the first surface 1010a and the second surface 1010b, and welded, thereby joining the end plate 101 and the main body 100 to each other.

[0036] The following describes the experimental procedure and results for measuring the weldability between the main body 100 and the end plate 101. Specifically, the length of the welding defect that occurs during the welding process between the stepped portion 1000b and the end plate 101 is measured.

[0037] More specifically, a drain hole is formed in the center of the stepped portion 1000b, and welded portions are formed on both sides of the drain hole in the stepped portion 1000b. In this case, the length of the welded portion on one side is 85 mm. In the experiment, when welding the welded portion on one side, the length of the welding defect that occurs is measured according to the thickness L1 of the stepped portion 1000b.

[0038] The results of measuring the length of welding defects that occur according to the thickness L1 of the stepped portion 1000b are shown in Table 1 below.

[0039] [Table 1]

[0040] Referring to Table 1, it can be seen that when the thickness L1 of the stepped portion 1000b is 1.1 mm or more, the length of the welding defect is reliably reduced. Therefore, the thickness L1 of the stepped portion 1000b can be 1.1 mm or more. Preferably, the thickness L1 of the stepped portion 1000b can be 1.2 mm or more. When the thickness L1 of the stepped portion 1000b is 1.2 mm or more, it can be seen that the length of the welding defect is significantly reduced.

[0041] Furthermore, considering the thickness of the joint portion of the end plate 101, the thickness L1 of the stepped portion 1000b can be 1.5 mm or less. Based on the cross-section shown in Figure 4, the sum of the thicknesses of the stepped portion 1000b and the end plate 101 can be 3 mm. In other words, the thicker the stepped portion 1000b, the thinner the end plate 101 can be.

[0042] If the thickness L1 of the stepped portion 1000b exceeds 1.5 mm, the thickness of the end plate 101 decreases, and due to the properties of penetration, melting, and bonding from the stepped portion 1000b to the end plate 101, a problem may arise in which the weldability is actually reduced. In other words, in order to ensure sufficient welding depth, the thickness L1 of the stepped portion 1000b should not be greater than the thickness of the end plate 101.

[0043] As a result, when the thickness L1 of the stepped portion 1000b of the bottom plate 1000 is designed to be 1.2 mm to 1.5 mm according to the embodiment of the present invention, the weldability between the bottom plate 1000 and the end plate 101 can be greatly improved.

[0044] In this way, by adjusting the thickness of the stepped portion 1000b relative to the main body portion 1000a, the main body 100 and the end plate 101 can be welded with a stronger bonding force. This stronger bonding force prevents the battery module case 10 from being damaged, and significantly increases the yield of the battery module.

[0045] The cover plate 102 can be connected to the main body 100 so as to cover one surface M3 of the main body 100 parallel to the longitudinal direction of the bottom plate 1000. For example, here, the surface M3 can mean the top surface M3. In this case, the cover plate 102 can be connected to the main body 100 so as to cover the open top surface M3 of the main body 100.

[0046] The following describes the battery module manufactured in the battery module case 10 described above. When describing the battery module according to the embodiment of the present invention, redundant information regarding the battery module case 10 described above will be omitted below.

[0047] A battery module according to an embodiment of the present invention includes a cell assembly structure housed inside a battery module case 10, which can store electrical energy and output the stored electrical energy to the outside via connecting terminals.

[0048] For example, a cell assembly can be manufactured by injecting an electrolyte solution into an electrode assembly that already contains an electrode assembly inside, thereby composing multiple activated electrode cells. In other words, a cell assembly can consist of multiple battery assemblies.

[0049] The battery module case 10 can house such a cell assembly internally, weld it in place, and protect the cell assembly from external factors such as shock and heat by isolating the cell assembly from contact with the external space.

[0050] Specifically, the battery module case 10 may include a main body 100, an end plate 101, and a cover plate 102. The main body 100 may also include a bottom plate 1000 and a side plate 1001, and the bottom plate 1000 may include a main body portion 1000a and a stepped portion 1000b.

[0051] As described above, by adjusting the thickness of the stepped portion 1000b, the length of the welding defect between the main body 100 and the end plate 101 can be reduced, and the bonding strength between the main body 100 and the end plate 101 can be increased. As a result, the possibility of damage to the battery module is reduced, and the yield of the battery module can be increased in the manufacturing process of the battery module.

[0052] The above description is merely illustrative of the technical concept of the present invention, and any person with ordinary skill in the art to which the present invention belongs can make various modifications and alterations without departing from the essential characteristics of the present invention.

[0053] Therefore, the embodiments disclosed in this invention are for illustrative purposes only, and not to limit the technical concept of the invention, and the scope of the technical concept of the invention is not limited by such embodiments.

[0054] The scope of protection of this invention shall be interpreted in accordance with the following claims, and all technical ideas within an equivalent scope shall be interpreted as being included within the scope of the rights of this invention. [Explanation of symbols]

[0055] 10 Battery Module Case 100 Main Unit 101 End Plate 102 Cover Plate 1000 Bottom Plate 1001 Side Plate 1000a Main body part 1000b Step section 1010 Joining part 1010a 1st page 1010b 2nd side 1010c 3rd page 101a Underside of end plate M1 front M2 rear M3 one side Thickness of the L1 step section Thickness of the L2 main body

Claims

1. A main body including a bottom plate and a pair of side plates connected to both sides of the bottom plate, An end plate that covers the front and rear surfaces of the main body, located in front of and behind the longitudinal direction of the bottom plate, and is connected to the main body, Includes a cover plate that covers one side of the main body parallel to the longitudinal direction of the bottom plate and is connected to the main body, The bottom plate is, The main body portion in the center of the bottom plate, The bottom plate includes stepped portions provided at both ends and protruding beyond the upper surface of the main body portion, In a longitudinal cross-sectional view of the battery module case, the stepped portion includes a first surface connected to the lower surface of the end plate and perpendicular to the lower surface of the end plate, and a second surface connected to the first surface and perpendicular to the first surface. The end plate includes a third surface perpendicular to the lower surface of the bottom plate, formed to correspond to the shape of the stepped portion, and a fourth surface connected to the third surface and perpendicular to the third surface. The longitudinal length of the second surface of the stepped portion is longer than the longitudinal length of the fourth surface of the end plate. Battery module case.

2. The battery module case according to claim 1, wherein the end plate is coupled and connected to the stepped portion.

3. The battery module case according to claim 2, wherein the end plate includes a joint portion that is recessed to correspond to the shape of the stepped portion.

4. The battery module case according to claim 3, wherein the stepped portion connects with the third surface and the fourth surface, thereby connecting the end plate and the main body to each other.

5. The battery module case according to claim 1, wherein the front and rear surfaces are formed via the stepped portion and the side plate.

6. The battery module case according to claim 5, wherein the thickness of the stepped portion is greater than the thickness of the main body portion.

7. The battery module case according to claim 6, wherein the thickness of the stepped portion is 1.2 mm or more.

8. A battery module case according to any one of claims 1 to 7, A battery module, including a cell assembly housed inside the aforementioned battery module case.

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