Lightweight and rigid battery module housing and battery pack including the same

Abstract

The present invention relates to a battery module housing including an accommodating portion in which a battery cell stack is mounted and which has a first side and a second side, a bolting portion for coupling between adjacent battery module housings, and a buffer portion for absorbing volumetric expansion of the battery cell stack, and includes a battery pack that can accommodate an increase in volume due to expansion of the battery cell stack, is reduced in weight, and has a minimized configuration.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2022-0057074 filed on May 10, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module housing and a battery pack including the same, particularly to a lightweight battery module housing with improved rigidity that relieves pressure caused by expansion of battery cells and enables connection between multiple battery modules, and a battery pack including the same. [Background technology]

[0003] Lithium secondary batteries, which are rechargeable and have high energy density, are attracting attention as a new energy source with environmentally friendly characteristics, as they can dramatically reduce the use of fossil fuels and do not produce by-products due to energy consumption.

[0004] Lithium secondary batteries have been attracting attention not only for wearable or portable devices but also as energy sources for devices with high power output and high energy density, such as electric vehicles.

[0005] In order to use the batteries as an energy source having such high output and high energy density, a plurality of lithium secondary batteries are housed in a housing to form a battery module or a battery pack.

[0006] In the lithium secondary battery, expansion and contraction of the active material layer occurs during charge and discharge, resulting in an increase and contraction of the volume of the battery cell. Such volume change of the battery cell may cause deformation of the battery module and the battery pack. Therefore, a structure for buffering the volume change of the battery cell is required.

[0007] Furthermore, in order to manufacture a battery pack with a high energy density, various structural improvements have been made to omit or replace components such as cross beams and a battery pack top plate that constitute conventional battery packs.

[0008] In this regard, Patent Document 1 discloses a battery module including a module housing formed in a rectangular tubular shape that defines an internal space for accommodating battery cells, and fastening flanges extending horizontally from upper regions on both sides of the module housing.

[0009] The battery module of Patent Document 1 discloses a configuration in which a shock absorber is attached to the outer surface of the side part of the module housing to protect the battery cells from external shocks. However, since the shock absorber is a separate component from the module housing, it is necessary to connect the shock absorber to the module housing, and when assembling it into a battery pack, components such as a rigid beam and a pack cover are provided.

[0010] Patent Document 2 discloses a battery module that includes a U-shaped frame with an open top that houses a battery cell stack, and an upper plate that covers the battery cell stack above the open U-shaped frame, with a recess formed in the side surface that recesses inward toward the battery cell stack.

[0011] In Patent Document 2, the recessed portion includes an elastic member that exerts an elastic force in the stacking direction of the battery cells, and therefore, it is possible to absorb pressure caused by expansion of the battery cells.

[0012] However, the battery module of Patent Document 2 does not provide a structure for connecting multiple battery modules, and includes a separate elastic member inside the frame to absorb the expansion of the battery cells, which results in a problem that the size of the battery module increases by the volume of the elastic member.

[0013] Therefore, there is a need for a structure that can increase energy density by manufacturing a battery pack with a minimum of components, without increasing the volume of the battery module even if it includes a component for buffering volume changes due to expansion of the battery cells. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Korean Patent Publication No. 2020-0112246 [Patent Document 2] Korean Patent Publication No. 2021-0053086 Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention has been made to solve the above problems, and aims to provide a battery module housing that absorbs volumetric expansion of battery cells, suppresses changes in size of the battery module, and stably connects a plurality of battery modules to form a battery pack, and a battery pack including the same. [Means for solving the problem]

[0016] To achieve this object, the present invention may include a receiving portion in which a battery cell stack is mounted and which includes a first side and a second side, a bolting portion for connecting adjacent battery module housings, and a buffer portion for absorbing volumetric expansion of the battery cell stack.

[0017] The bolting portions may be located at upper and lower ends of the first and second sides, respectively.

[0018] The bolting part may have a structure in which a through hole is formed in a fastening part extending perpendicularly to the first side and the second side.

[0019] The fastening portion may be formed in the overall length direction of the receiving portion.

[0020] The buffering portion may have a buffering structure that protrudes from at least one of the first side surface and the second side surface in a width direction parallel to an expansion direction of the battery cell stack.

[0021] The cushioning structure may include a cushion portion that is horseshoe-shaped in vertical cross section.

[0022] A guard may be further included on the outside of the cushion part.

[0023] The buffer structure may be formed in the overall length direction of the receiving portion.

[0024] The thickness of the first and second sides may decrease from the center toward the upper and lower ends.

[0025] The protruding height of the buffer portion may be equal to or smaller than the protruding height of the bolting portion.

[0026] The receiving part may further include an upper surface and a lower surface, and the upper surface and the lower surface may have a hollow interior.

[0027] The receiving portion, the bolting portion, and the buffer portion may have a shape manufactured by extruding a metal material.

[0028] The present invention provides a battery pack in which battery modules, each including the battery module housing, are connected in a horizontal direction.

[0029] The present invention can also be provided in various combinations of the above configurations. [Effects of the Invention]

[0030] As described above, the battery module housing according to the present invention can absorb the volume expansion of the battery cell stack by the buffer portion having a structure integrated with the accommodating portion.

[0031] In addition, the bolting portion, which is a connecting structure for connecting the battery module housings, and the buffer portion, which is a volume expansion buffer structure, are provided in a form that protrudes from the first and second sides, thereby minimizing the increase in volume of the battery module housing.

[0032] Furthermore, when constructing a battery pack, the battery module housing can replace the construction of the battery pack housing, thereby minimizing the number of battery pack components. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a perspective view of a battery module according to a first embodiment. [Figure 2] FIG. 2 is a front view of the battery module housing of FIG. [Figure 3] FIG. 10 is a perspective view of a battery module according to a second embodiment. [Figure 4] FIG. 4 is a front view of the battery module housing of FIG. 3. [Figure 5] FIG. 2 is a perspective view showing a state in which the battery modules of FIG. 1 are arranged side by side. [Figure 6] 1 is a perspective view of a battery pack according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that will enable a person skilled in the art to easily carry out the present invention. However, in describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations will be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0035] Furthermore, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only a direct connection but also an indirect connection via another element therebetween. Furthermore, unless otherwise specified, "including a certain element" does not mean that other elements are excluded, but that other elements may also be included.

[0036] Furthermore, descriptions that limit or add specific elements are applicable to all inventions and are not limited to a particular invention unless otherwise specified.

[0037] Furthermore, throughout the description of the present invention and the claims, the singular includes the plural unless otherwise stated.

[0038] Furthermore, throughout the description of the present invention and the claims, unless otherwise specified, "or" includes "and." Therefore, "including A or B" means the three cases of including A, including B, or including both A and B.

[0039] The invention will now be explained with reference to the drawings and in conjunction with detailed embodiments.

[0040] FIG. 1 is a perspective view of a battery module according to a first embodiment, and FIG. 2 is a front view of the battery module housing of FIG.

[0041] Referring to Figures 1 and 2, the battery module 100 accommodates a battery cell stack, in which multiple battery cells are arranged in close contact, inside a battery module housing, and the battery cell stack is arranged in a space formed between a first side 113 and a second side 114 of the accommodation portion.

[0042] The battery module housing includes a rectangular prism-shaped monoframe receiving portion having an upper surface 111, a lower surface 112, a first side surface 113, and a second side surface 114 whose outer surfaces intersect perpendicularly, a bolting portion 120 for connecting adjacent battery module housings, and a buffer portion 131 for absorbing volumetric expansion of the battery cell stack.

[0043] End plates 115 are attached to both ends of the receiving portion in the overall length direction y to seal the receiving portion, and module terminals 116 are positioned so as to protrude from the end plates 115 to the outside.

[0044] The bolting portion 120 is configured to allow screws 122 to be fastened when multiple battery modules are connected to each other while arranged side by side in the width direction x, and is located at the upper and lower ends of each of the first side 113 and the second side 114.

[0045] The bolting part 120 has a structure in which a through hole is formed in a fastening part 121 extending perpendicularly to the first side 113 and the second side 114, and the battery module can be connected by fastening a nut to a screw 122 inserted into the through hole.

[0046] Specifically, since it is difficult to fasten nuts when the battery modules are positioned adjacent to each other and the fastening portions overlap, the battery modules may be joined by first welding a nut to one of the battery modules that are positioned adjacent to each other and have overlapping fastening portions, and then fastening a bolt to the nut.

[0047] Alternatively, the battery modules may be fastened by inserting rivet studs / nuts into the through holes of the fastening portion, or by inserting flow drill screws into the through holes.

[0048] In the following description of the connection of the battery modules, the term "screw" includes screws and rivets inserted into the through-holes of the fastening portion 121, and the type thereof is not limited.

[0049] The fastening portion 121 is formed along the entire length direction y of the receiving portion. Fig. 1 shows a structure in which the fastening portion 121 is formed continuously along the entire length direction y. However, the fastening portion 121 may also be formed discontinuously along the entire length direction y.

[0050] The battery cell stack may be formed by closely arranging a plurality of pouch-type battery cells. The pouch-type battery cells may be arranged with their electrode planes parallel to the yz plane. Here, during charging and discharging of the battery module, the pouch-type battery cells expand and contract in volume along the width direction x.

[0051] Therefore, the present invention provides a buffering portion 131 as a means for alleviating pressure caused by volumetric expansion of the pouch-type battery cells. Specifically, the buffering portion 131 may have a shape including a buffering structure protruding in the width direction x from at least one of a first side surface 113 and a second side surface 114 that form outer surfaces at both ends of the width direction x of the battery module housing.

[0052] Therefore, in Figures 1 and 2, one buffer portion 131 is formed on each of the first side surface 113 and the second side surface 114, and the buffer portion 131 on the first side surface 113 and the buffer portion 131 on the second side surface 114 are located at different z-direction positions.

[0053] Therefore, when two or more battery modules are arranged and connected along the entire width direction x, the buffering portion 131 of the first side surface 113 and the buffering portion 131 of the second side surface 114 do not overlap each other and can be arranged at different positions.

[0054] The buffer structure includes a horseshoe-shaped cushion portion 132 in vertical cross section. Therefore, as shown in the lower part of Figure 2, when the battery module housings are joined by fastening screws 122 and the left battery module housing expands in the (+)x direction and the right battery module housing expands in the (-)x direction due to expansion of the battery cells, the buffer portion 131 is deformed such that its size in the x direction decreases and its size in the z direction increases. In other words, the buffer portion 131 can act as a cushion or spring that absorbs the volumetric expansion of the battery module housings.

[0055] The buffer structure is formed along the entire length direction y of the receiving part. Fig. 1 shows a structure in which the buffer part 131 is formed continuously along the entire length direction y. However, the buffer part 131 may be formed discontinuously along the entire length direction y.

[0056] In one specific example, the thickness of the first side surface 113 and the second side surface 114 may be configured to decrease from the center in the z direction toward the upper end and the lower end. Considering that deformation due to volume expansion of the battery module housing occurs in the x direction and deformation is greatest at the center in the z direction, forming the thickness at the center in the z direction relatively thicker can minimize deformation of the battery module housing.

[0057] The battery module housing according to the present invention has a bolting portion 120 formed on a first side surface 113 and a second side surface 114, and a buffer portion 131 provided on at least one of the first side surface 113 and the second side surface 114, and the bolting portion 120 and the buffer portion 131 are arranged so as not to overlap each other on the first side surface 113 and the second side surface 114. Therefore, a structure can be formed that minimizes an increase in the external size of the battery module housing even while including both a structure for connecting the battery modules and a structure for mitigating volumetric expansion.

[0058] Meanwhile, the length of the buffering part 131 in the x direction is smaller than the length of the bolting part 120 in the x direction. Therefore, when two or more battery module housings are combined and the battery cells are not expanded, the buffering part 131 does not contact the first side or the second side of the adjacent battery module housing but is spaced apart by a predetermined distance.

[0059] That is, when the battery cell is not expanded and the battery module housing is joined without any pressure being applied to the buffer portion 131, when the battery cell expands, the buffer portion and the first side or second side of the adjacent battery module housing begin to come into contact, and the buffer portion can soon be pressurized.

[0060] In addition, even if the first side 113 and the second side 114 expand by the length of the bolting part 120 in the x direction, when multiple battery modules are fastened and coupled to the bolting part 120 with screws, the size of the entire battery module in the overall width direction x can be prevented from increasing.

[0061] The battery module housing according to the present invention has a shape in which the interior of the upper surface 111 and the lower surface 112 is formed with a hollow 141, thereby reducing the weight of the battery module housing by the amount of the portion removed by forming the hollow 141. Furthermore, the upper surface 111 and the lower surface 112 are provided with partition walls 142 in the thickness direction z, and the hollow 141 is formed between the partition walls 142, thereby ensuring the rigidity of the battery module housing by the partition walls 142.

[0062] The battery module housing has an integral structure manufactured by extruding a metal material, and the accommodating section, bolting section, and buffer section are all configured as an integral structure.

[0063] The metallic material may include aluminum, carbon steel, stainless steel, and alloys thereof.

[0064] FIG. 3 is a perspective view of a battery module according to a second embodiment, and FIG. 4 is a front view of the battery module housing of FIG.

[0065] Referring to Figures 3 and 4, the battery module according to the second embodiment differs from the battery module housing according to the first embodiment in that the battery module housing further includes a guard 133 on the outside of the cushion portion 132, which is horseshoe-shaped in vertical cross section and forms the buffer portion 131.

[0066] 3 and 4 does not have a buffer portion 131 formed on the first side surface 113, but only on the second side surface 114. The buffer portion 131 formed only on the second side surface 114 includes two cushion portions 132 and a guard 133 that are horseshoe-shaped in vertical cross section, so that the entire buffer portion 131 and bolting portion 120, including the accommodating portion, cushion portions 132, and guards 133, have an integrated structure manufactured by extruding a metal material.

[0067] 4, when the two battery module housings are fastened and connected with screws 122, the second side surface 114 of the left battery module housing and the first side surface 113 of the right battery module housing are adjacent to each other and connected such that there is a gap between the guard 133 of the second side surface 114 of the left battery module housing and the first side surface 113 of the right battery module housing. Therefore, when the battery module housings expand in the x direction, the expanded volume can be accommodated within the buffer part 131 and the gap.

[0068] Additionally, the description of the battery module and battery module housing according to the first embodiment can be similarly applied to the description of the battery module and battery module housing according to the second embodiment.

[0069] FIG. 5 is a perspective view showing the battery modules of FIG. 1 arranged side by side.

[0070] 5, battery modules 100, each including a battery module housing, are arranged adjacent to each other in the horizontal direction x, and a battery pack in which a plurality of battery modules are connected can be manufactured by fastening the battery modules to bolting portions 120 of the battery module housings with screws. The battery modules 100 are connected such that a buffer portion 131 is disposed between a first side and a second side of the battery modules 100, so that the volume of the battery modules expanding in the x direction can be accommodated in the buffer portion 131.

[0071] FIG. 6 is a perspective view of a battery pack according to the present invention.

[0072] Referring to FIG. 6, the battery pack 200 has a structure in which the upper and lower surfaces of the battery module housings are exposed when a plurality of battery modules 100 are mounted in a battery pack frame 210.

[0073] The battery module housing according to the present invention has a structure with improved rigidity and strength against external impacts by forming partition walls and hollows on the top and bottom surfaces. Therefore, the battery module housing can replace the top plate and pack tray of the battery pack, eliminating the need for a separate top plate and pack tray during battery pack assembly. Furthermore, when the battery modules are connected via a buffer part consisting of a bolting part, a cushioning part, and a guard, the bolting part and buffer part can function as the cross beam of a conventional battery pack, so the cross beam can be omitted in the battery pack according to the present invention.

[0074] The battery pack frame 210 may be composed of a first member 211, a second member 212, a third member 213, and a fourth member 214 that are vertically connected to each other, and the first member 211, the second member 212, the third member 213, and the fourth member 214 may be composed of separate members that can be separated and connected to each other.

[0075] Meanwhile, a mounting portion 215 for mounting the battery pack to the device may be required. The mounting portion 215 may be provided at the bottom end of at least one of the first member 211, the second member 212, the third member 213, and the fourth member 214. Therefore, no additional parts are required for mounting the battery pack to the device.

[0076] In this way, when using the battery module housing according to the present invention, deformation due to expansion of the battery cell stack can be accommodated, multiple battery modules can be easily connected, and the number of components constituting the battery pack can be reduced, thereby reducing weight and improving rigidity.

[0077] Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above content. [Explanation of symbols]

[0078] 100 battery modules 111 Top surface 112 Bottom surface 113 First aspect 114 Second aspect 115 End Plate 116 Module terminal 120 Bolting Section 121 Fastening part 122 screws 131 Buffer section 132 Cushion part 133 Guard 141 Hollow 142 Bulkhead 200 battery packs 210 Battery pack frame 211 First member 212 Second member 213 Third member 214 Fourth member 215 Mounting part

Claims

1. a housing portion in which the battery cell stack is mounted and which includes a first side surface and a second side surface; a bolting portion for connecting adjacently arranged battery module housings; a buffer portion that is provided integrally with the housing portion and serves as a cushion or spring to absorb volume expansion of the battery cell stack; a battery module housing.

2. The battery module housing according to claim 1 , wherein the bolting portions are located at upper and lower ends of the first and second side surfaces, respectively.

3. The battery module housing of claim 2 , wherein the bolting portion has a structure in which a through hole is formed in a fastening portion extending perpendicularly to the first side surface and the second side surface.

4. The battery module housing according to claim 3 , wherein the fastening portion is formed in the overall length direction of the receiving portion.

5. The battery module housing according to claim 1 , wherein the buffer portion has a buffer structure that protrudes from at least one of the first side surface and the second side surface in a width direction parallel to an expansion direction of the battery cell stack.

6. The battery module housing according to claim 5 , wherein the buffer structure includes a cushion portion that is horseshoe-shaped in vertical cross section.

7. The battery module housing according to claim 6 , further comprising a guard on the outside of the cushion portion.

8. The battery module housing according to claim 5 , wherein the buffer structure is formed in the overall length direction of the receiving portion.

9. The battery module housing of claim 1 , wherein the thickness of the first and second sides decreases from the center toward the upper and lower ends.

10. The battery module housing of claim 1 , wherein the protruding height of the buffering portion is equal to or smaller than the protruding height of the bolting portion.

11. the housing further includes an upper surface and a lower surface; The battery module housing according to claim 1 , wherein the upper and lower surfaces have a hollow interior.

12. The battery module housing according to claim 1 , wherein the receiving portion, the bolting portion, and the buffer portion are manufactured by extrusion molding of a metal material.

13. A battery pack in which battery modules, each including the battery module housing according to any one of claims 1 to 12, are connected in a horizontal direction.

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