Patent Application
20240072348
The present invention relates to a battery pack.
More specifically, the present invention relates to the battery pack that can regulate movement of a plurality of battery modules in the height direction accommodated in the battery pack.
This application claims the benefit of a priority based on Korean Patent Application No. 10-2021-0143937, filed on Oct. 26, 2021, and the entire contents of the Korean patent application are incorporated herein by reference.
Recently, secondary batteries capable of charging and discharging have been widely used as energy sources of wireless mobile devices. Further, secondary batteries have been drawing attention as energy sources of electric vehicles, hybrid electric vehicles, and the like proposed as solutions to solve air pollution of existing gasoline vehicles using fossil fuels, diesel vehicles that use fossil fuels. Accordingly, kinds of applications using secondary batteries have diversified in many directions because of the advantages of secondary batteries, and in the future, secondary batteries are expected to be applied to even more fields and products.
In addition, as a power source of Electric Storage System (ESS) and electric vehicles, etc., the demand for the battery module that internally accommodates a plurality of secondary batteries that are electrically connected in series/parallel and the demand for the battery pack that is composed of such battery modules have been increasing.
Such battery module/battery pack has an outer housing made of a metal material in order to protect a plurality of secondary batteries from external shock or to store a plurality of secondary batteries.
The battery pack may be configured in various forms such as installing battery modules in a plurality of individual accommodating grooves separated by partition walls, or accommodating a plurality of battery modules at once in a single battery pack case, etc. The form of the battery pack can vary depending on the shape, size, and electrical connection structure of the battery module being accommodated.
When a plurality of battery modules is accommodated in a single battery pack case all at once, an adhesive resin may be applied to the bottom of the pack case in order to adhesively fixate the battery modules. In this case, because the adhesive resin is not evenly charged between the battery module and the pack case, the height of the battery modules may not be even. In the case of large battery modules accommodating a plurality of battery cells, because the strength of its own weight pressurizing adhesive resin layer is big, the problem of height unevenness mentioned above may not be significant. However, in the case where a battery pack accommodates small battery modules accommodating relatively small number of battery cells, it might be difficult to uniformly couple busbars between the modules due to the height unevenness mentioned above.
The present applicant formed a battery cell assembly by forming a longitudinal direction unit cell by arranging battery cells in series in the longitudinal direction, and stacking two or more rows of the longitudinal direction unit cell in the thickness direction of the battery cell. In addition, based on the shape of such battery cell assembly, a module case was manufactured to be extended in the longitudinal direction and was manufactured in a shape surrounding the battery cell assembly. Such battery module accommodates relatively small number of battery cells in each module case, and by stacking the battery modules in the longitudinal direction or thickness direction of the battery cell like Lego blocks, it can freely configure a battery pack considering the space where the battery module is installed or the space where the battery pack is installed. As such, because the battery module suggested by the present applicant can manufacture various types of battery packs depending on the stacking (designing) method, it can be referred to as an expandable battery module.
However, the expandable battery module 10 is relatively lightweight because it accommodates small number of battery cells. Therefore, when a pack case charged with adhesive resin layer is accommodating a plurality of battery modules 10, the height in the width direction (perpendicular to the longitudinal direction) of the battery module may not be uniform as shown in
For example, it is possible to assemble battery modules into a pack case with the same height without charging the adhesive resin layer, and even if it gets charged, the battery module 10 can be evenly pressurized and assembled into the pack case, eliminating the height unevenness during assembly as illustrated in
However, when a plurality of battery modules is used after being stacked and stored inside the battery pack, assembly deformation may occur due to swelling as the battery cell within the battery module goes through the charge-discharge process under the conditions of use. When a plurality of battery cells within the battery module experience swelling, the module case thereupon receives stress. Consequently, as illustrated in the bottom drawing in
Accordingly, when assembling a plurality of battery modules by layering inside the pack case, development of a battery module related technology is required that allows the height of each battery module to be even, and prevents assembly deformation in the battery module due to swelling when using the battery pack.
The present invention has been proposed to solve the above problems, and the present invention is directed to provide a battery pack capable of maintaining a uniform height of the battery modules even after assembling a plurality of battery modules in a pack case.
In addition, the present invention is directed to provide a battery pack with a coupling structure that can maximize an internal space utilization by stably fixing a battery module inside the pack by minimizing fastening points, and can improve the coupling rigidity between the battery module and the pack case.
The battery pack according to present invention that can solve the above problems includes: a plurality of battery modules, each battery module accommodating a plurality of battery cells; a pack case configured to accommodate the plurality of battery modules stacked in a horizontal direction; and a pair of retention bars extending along the stacking direction of the battery modules, the pair of retention bars being coupled to the pack case while pressing upper surfaces at opposite ends of the stacked battery modules.
As an example, wherein the plurality of battery cells of each battery module may be arranged as a battery cell assembly in which a plurality of longitudinal unit cells, each of which is composed of at least two battery cells of the plurality of battery cells arranged in a line in a longitudinal direction, are stacked in a thickness direction of the battery cells, and each battery module may have a cuboid shape elongated in the longitudinal direction to accommodate the battery cell assembly.
As a specific example, the longitudinal direction unit cells may be arranged in two rows in the longitudinal direction, a terminal busbar may be connected between the battery cells arranged in the longitudinal direction, and an end of the terminal busbar may be exposed at an upper portion of the battery module.
In addition, the battery pack may comprise a high voltage busbar extending in a width direction of the battery module and coupled to the terminal busbar of each battery module.
As an example, the battery pack may have a pack case that may include: an upper frame; a lower frame on which the battery modules are located and a front side frame, a rear side frame, a left side frame, and a right side frame are located between the upper frame and the lower frame, the front side frame, the rear side frame, the left side frame, and the right side frame surround the stacked battery modules.
Specifically, the lower frame, the front side frame, the rear side frame, the left side frame, and the right side frame may be integrally provided.
In addition, the pair of retention bars may be coupled to the left side frame and the right side frame.
As an example, each of the left side frame and the right side frame may have a coupling protrusion on an inner side facing the battery modules, and the pair of retention bars may be coupled to upper surfaces of the coupling protrusion to press the upper surface of at the opposite ends of the battery modules.
As a more specific example, each of the left side frame and the right side frame may include a fitting groove at an inner surface thereof, the fitting groove may be configured to receive one side of a corresponding retention bar of the pair of retention bars, the fitting groove being located above the coupling protrusion, the one side of the corresponding retention bar is fitted to the fitting groove, and the corresponding retention bar may be coupled to the upper surface of the coupling protrusion by a fastening member.
As another example, each retention bar of the pair of retention bars may be composed of an upper plate and a bending portion bent downward from the upper plate, and when the upper plate presses the upper surface at a corresponding opposite end of the battery modules, the bending portion may be located in a gap between an inner surface of the left side frame and the right side frame and the corresponding opposite end of the battery modules, the pair of retention bars may be coupled to the left side frame and the right side frame by a fastening member passing through the upper plate and the bending portion of a corresponding retention bar of the pair of retention bars to be coupled to the coupling protrusion.
In the example above, the inner surface of each of the left side frame and the right side frame may include a fitting groove above the coupling protrusion, and one side of the upper plate of the corresponding retention bar may be fitted to the fitting groove.
As an example, an adhesive resin layer may be filled between the battery modules and the lower frame.
In addition, an adhesive resin layer may be filled between the battery modules and the upper frame.
In the example above, a heat sink may be located between the upper frame and the adhesive resin layer filled between the battery modules and the upper frame. And an insulating member may be located between the upper frame and the heat sink.
According to the present invention, because the height of a plurality of battery modules can be maintained uniformly when being assembled into the pack case, it can make welding of an electronic components such as a busbar easier, and can prevent gap between the battery modules from occurring when a heat sink is installed in the upper part.
In addition, even after the battery module is assembled and accommodated into the pack case, it can prevent the height deformation due to swelling.
Moreover, when assembling a battery module into a pack, the present invention is directed to provide a battery pack with a coupling structure that can maximize an internal space utilization by stably fixing the battery module inside the pack by minimizing the fastening points, and can improve the coupling rigidity between the battery module and the pack case.
Hereinafter, the present invention will be described in detail. First, the terms and words used in this specification and claims should not be interpreted as limited to commonly used meanings or meanings in dictionaries, and should be interpreted with meanings and concepts which are consistent with the technological scope of the invention based on the principle that the inventors have appropriately defined concepts of terms in order to describe the invention in the best way.
The terms “comprise,” “include” and “have” used herein designate the presence of characteristics, numbers, steps, actions, components or elements described in the specification or a combination thereof, and it should be understood that the possibility of the presence or addition of one or more other characteristics, numbers, steps, actions, components, elements or a combination thereof is not excluded in advance.
In addition, when a part of a layer, a film, a region or a plate is disposed “on” another part, this includes not only a case in which one part is disposed “directly on” another part, but a case in which a third part is interposed therebetween. In contrast, when a part of a layer, a film, a region or a plate is disposed “under” another part, this includes not only a case in which one part is disposed “directly under” another part, but a case in which a third part is interposed therebetween. In addition, in this application, “on” may include not only a case of disposed on an upper part but also a case of disposed on a lower part.
The battery pack according to the present invention comprises: a battery module accommodating a plurality of battery cells; a pack case in which a plurality of battery modules are stacked in a horizontal direction and accommodated; a retention bar extended along the stacking direction of the battery module and is coupled to the pack case while pressing the upper surface of both sides of the stacked battery modules.
There is no limit to the shape, size, type, etc. of the battery module accommodated in the battery pack of the present invention. In addition, the number of battery cells accommodated in the battery module is not limited. However, as illustrated above, in the case of small battery modules that have a small number of battery cells, it has a greater need for a retention bar described below because the problem of height unevenness is big. Especially, because the expandable battery module proposed by the present applicant has a module case extended lengthwise in the longitudinal direction and has a battery module stacked and accommodated inside the pack case in one direction (horizontally or in the width direction perpendicular to the longitudinal direction of the battery module) as illustrated in
Hereinafter, the present invention will be described by referring to the battery module with such expandability.
As illustrated in
The battery cell assembly 11 of the battery module 10 illustrated in
The present invention also comprises a pack case 20 that accommodates the battery module.
In
The pack case 20 has an upper frame 20A, a lower frame 21 on which the battery modules 10 are stacked and settled, and side frames 22,23 that are positioned between the upper and the lower frames.
The side frames 22,23 are provided at four locations on the front, back, left, right sides.
In
An adhesive resin layer R may be applied to the lower pat frame 21, and when the battery modules 10 are stacked and arranged in the lower frame 21, this adhesive resin layer R serves to fix the battery modules.
When the battery module 10 is accommodated and fixed inside the lower pack case 20B, the upper frame 20A is coupled by covering the lower pack case 20B.
The adhesive resin layer R may be applied between the upper frame 20A and the battery module even after the battery module 10 is accommodated as occasion demands. When thermally conductive thermal resin is used as the adhesive resin layer R, aside from the adhesive fixing function, it can perform a heat dissipation function. A silicon-based resin, modified silicone resin, acrylic resin, etc. can be used as a thermally conductive thermal resin. If such thermally conductive thermal resin is charged between the battery module 10 and the upper frame 20A, or between the battery module 10 and the lower frame 21 of the lower pack case 20B, it can effectively absorb heat generated inside the battery pack 100. In addition, if a heat sink 40 is installed in the lower portion of the upper frame 20A, it can further improve heat dissipation efficiency by transferring heat from the thermally conductive thermal resin to the heat sink 40.
If necessary, an insulating member 50 can be installed between the upper frame 20A and heat sink 40.
As illustrated above, in a case where the a plurality of battery modules 10 are stacked and accommodated into a single pack case 20 in a specific direction, the height of the battery module 10 may not be kept the same inside the battery pack 100 depending on the charge state of the adhesive resin layer R formed between the battery module 10 and the pack case 20 (refer to
The retention bar in the present disclosure means a bar for stably fixating and maintaining the battery module 10 inside the pack case 20 by pressing the battery module 10 so as not to fluctuate in height as described above. Because the retention bar 30 is fixing and maintaining a plurality of battery modules 10, it extends along the stacking direction of the battery modules 10 and is coupled to the pack case. That is, when the battery modules 10 are stacked in the horizontal direction within the pack case, the retention bar 30 regulates the movement of the battery module 10 in the height direction (Z-direction) by being extended and installed in the stacked horizontal direction.
While the illustration of the battery module 10 was omitted and only the pack case was illustrated in
Specifically, the retention bar 30 regulates the movement of the battery module 10 by pressurizing upper surface of both sides of the battery module 10 and being coupled to the pack case 20. That is, two retention bars 30 are provided in pairs along the stacking direction of the battery module 10 in order to pressurize the upper surface of both sides of the battery module 10.
In addition, the retention bar 30 has a pressurizing portion that pressurizes the upper surface of the battery module 10 and the pressurizing portion is coupled to the pack case 20. Referring to
The shape of the retention bar 30 and its coupling structure with the pack case 20 are not restricted to the above, and may be available in other shapes. For example, as in the structure of inserting the retention bar 30 into the fitting groove of the side frames 22,23 of the pack case 20, it can couple the retention bar 30 to the pack case 20 without the fastening member B. However, if there is the fastening member B, the retention bar 30 can be more firmly coupled to the pack case 20. In addition, it is favorable to fasten with the fastening member B in order to increase the upper pressing force of the pack case 20. If the retention bar 30 is coupled to the pack case 20 without the fastening member B, the coupling process may be simplified. Accordingly, it becomes advantageous to automate the process of coupling the retention bar. However, even in the case of fastening with a fastening member, it is possible to fasten a plurality of fastening points by a robot or the like. Therefore, the battery pack assembly process can be automatized using the retention bar of the present invention, and thus it is convenient to apply to mass-production process.
Similar to
First, an adhesive resin layer R is applied to the lower pack case 20B which is made of a lower frame 21 and side frames 22,23. Alternatively, after accommodating the battery module 10 into the lower pack case 20B, the adhesive resin layer R can be charged between the battery module 10 and the lower pack case 20B through a predetermined injection hole.
Next, the expandable battery modules 10 are stacked and disposed in the horizontal direction inside the lower pack case 20B. Horizontal direction in the present embodiment is the longitudinal direction of the pack using the battery pack 100 as the reference, and it is the width direction of the module using the battery module 10 as the reference. In any case, the retention bar 30 needs to be installed to extend along the stacking direction of the battery module 10.
After the battery module 10 is arranged, a pair of left and right retention bars 30 are coupled to the left and right side frames 23 of the lower pack case 20B as illustrated in
When battery modules are installed at a uniform height inside the battery pack 100 by the retention bar 30, the battery modules can be electrically connected by connecting a high-voltage busbar BB to the terminal busbar T exposed on the battery module 10. Here, because the battery modules are disposed at a uniform height in a structure specific to the present invention, the high-voltage busbar BB may also be welded to the battery modules at a uniform height. In addition, it is possible to install and connect parts necessary for the battery pack, such as a low-voltage busbar and a sensing cable.
Although not illustrated in
Meanwhile, in the coupling structure of the present invention shown in
In addition, even after assembling the battery pack 100, when swelling as in
The embodiments disclosed in the present invention are considered in a descriptive sense only and not for purposes of limitation, and the scope of the invention is not limited by the embodiments. It should be interpreted that the scope of the invention is defined by the appended claims and encompasses all modifications and equivalents that fall within the scope of the appended claims.
Meanwhile, in the present specification, although the terms such as, upward, downward, left, right, forward, and rearward, which indicate directions, have been used, the terms are only for the sake of convenience in the description, and it is clear that the directions change according to a position of a target object or observer.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0143937 | Oct 2021 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2022/015524 | 10/13/2022 | WO |
