Battery pack

Abstract

In one example, a battery pack includes a base plate, side plates coupled along edges of the base plate to form an accommodation space therein, a single cross beam coupled to the base plate to collectively partition the inner accommodation space of the base plate laterally, and a plurality of battery cell assemblies mounted in the accommodation space partitioned by the single cross beam, and a guide structure is interposed between the plurality of battery cell assemblies and the single cross beam to regulate the position of each battery cell assembly on an XY plane corresponding to the surface of the base plate.

Description

[Technical field]

[0001] The present invention relates to a battery pack, and more particularly to a battery pack in which a single cross beam is used to improve the structural rigidity and space utilization rate of a pack case, and which can facilitate installation of battery cell assemblies in the pack and ensure a firm fixed state.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0167141, filed December 2, 2022, and Korean Patent Application No. 10-2023-0036409, filed March 21, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference. [Background technology]

[0003] In order to improve the space utilization rate of a battery pack, a battery pack with a cell-to-pack structure has been proposed. The cell-to-pack structure has the advantage that it can improve the space utilization rate of a battery pack by directly assembling multiple battery cells into a battery pack without a structure for modularizing the battery cells.

[0004] In the cell-to-pack structure, since a separate module housing is omitted or simplified, it is important to ensure the rigidity of the battery pack. For example, a side frame may be coupled to a battery cell assembly (corresponding to a conventional battery module) in which multiple battery cells are assembled, and the side frame of the battery cell assembly housed in a pack case may be designed to function as a cross beam of the conventional battery pack.

[0005] However, when multiple battery cell assemblies are arranged in the width direction of the pack case in order to increase the capacity of the battery pack, the side frames of adjacent battery cell assemblies facing each other at the center of the battery pack in the width direction are not connected to each other, which causes a problem of weakening the structural rigidity of the battery pack.

[0006] To solve this problem, a structure can be designed in which a center beam is placed in the center of the battery pack in the longitudinal direction, and the side frames that were not connected to each other are connected and fixed to the center beam. However, this structure in which the side frames and center beam are combined causes problems such as a complicated battery pack assembly process, an increase in the weight of the battery pack due to an increase in the number of parts, and a decrease in the energy density of the battery pack due to a decrease in space utilization rate as in the past. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a battery pack having a cell-to-pack structure that can maintain good rigidity even with a simplified structure and can firmly regulate the position of the battery cell assemblies while simplifying the process of mounting a plurality of battery cell assemblies.

[0008] However, the technical problem that the present invention aims to solve is not limited to the above-mentioned problem, and other problems not mentioned can be clearly understood by a person skilled in the art from the description of the invention described below. [Means for solving the problem]

[0009] The present invention relates to a battery pack, and in one example, includes a base plate, side plates coupled along the edges of the base plate to form an accommodation space therein, a single cross beam coupled to the base plate to collectively partition the inner accommodation space of the base plate laterally, and a plurality of battery cell assemblies mounted in the accommodation space partitioned by the single cross beam, and a guide structure is interposed between the plurality of battery cell assemblies and the single cross beam to regulate the position of each battery cell assembly on an XY plane corresponding to the surface of the base plate.

[0010] In one embodiment, the battery cell assembly includes a plurality of cell stacks and a bus bar frame assembly that is mechanically and electrically coupled to the plurality of cell stacks at both lateral ends from which the leads of the cell stacks protrude, and the guide structure may include a guide slot that is concavely formed along the height direction of the single cross beam, and a guide rib that is provided on the bus bar frame assembly to be guided along the guide slot.

[0011] The guide structures may be provided at four corners of the battery cell assembly.

[0012] The guide slots may then be formed across the entire height of the single cross beam, and the guide ribs may be formed along at least a portion of the entire height along a side of the busbar frame assembly.

[0013] Meanwhile, in the battery pack of the present invention, a fixing structure that regulates the position of each battery cell assembly on the Z axis may be interposed between the plurality of battery cell assemblies and the single cross beam.

[0014] The fixing structure may be a first groove formed in a concave shape in a lower portion of the single cross beam, and a first hook provided on the bus bar frame assembly to engage with the first groove.

[0015] In one embodiment, the first hook is a resilient hook that operates resiliently, and the first groove and the first hook can form a snap-fit ​​joint.

[0016] The fixing structure may further include a second groove formed in a concave shape on an upper portion of the single cross beam, and a second hook provided on the bus bar frame assembly to contact a step of the second groove.

[0017] In one embodiment, the second groove may be an open groove that is open at the top, and the second hook may be a rigid hook that contacts a lower step of the second groove to support the battery cell assembly.

[0018] The first groove and the second groove may be disposed so as to be separated from each other on the inside and outside of the guide slot as a boundary.

[0019] For example, the first hook may be disposed closer to the outer periphery of the battery cell assembly than the second hook.

[0020] The first and second hooks may be disposed on a side surface of the bus bar frame assembly together with the guide rib. Effect of the Invention

[0021] In the battery pack of the present invention having the above-mentioned structure, the storage space inside the pack case is divided by a single cross beam, and the single cross beam is connected as one across the entire lateral direction of the pack case. Therefore, there is no center beam configuration, which simplifies the assembly process of the battery pack, reduces the number of parts, and reduces the weight of the battery pack. Space utilization rate is improved, while the single cross beam can maintain good rigidity of the pack case.

[0022] In addition, the guide structure and fixing structure interposed between the plurality of battery cell assemblies and the single cross beam accurately regulate the installation position of the plurality of battery cell assemblies when they are mounted between a pair of single cross beams.

[0023] However, the technical effects that can be obtained by the present invention are not limited to the effects described above, and other effects not mentioned can be clearly understood by those of ordinary skill in the art from the description of the invention described below.

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. [Brief description of the drawings]

[0025] [Figure 1] 1 is a diagram showing an overall internal structure of a battery pack according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing a structure in which a battery cell assembly is mounted in a pack case. [Diagram 3] 1 is an enlarged view showing a structure of a guide structure interposed between a battery cell assembly and a single cross beam; [Figure 4] 13 is a diagram showing a structure in which battery cell assemblies are coupled to a single cross beam via a guide structure. [Diagram 5] 13 is a diagram showing the structure of a fixing structure interposed between a battery cell assembly and a single cross beam; [Figure 6] 1 is a diagram showing a fixing structure provided in a battery cell assembly. [Figure 7] 1 is a diagram showing a fixed structure provided on a single cross beam. [Figure 8] 6 is a rear view of the structure of the fixed structure in FIG. 5. [Figure 9] 6 is a top view of the structure of the fixed structure in FIG. 5. [Figure 10] FIG. 9 is a cross-sectional view of part “A” in FIG. 8. [Figure 11] FIG. 9 is a cross-sectional view of part “B” in FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below.

[0027] However, this is not intended to limit the invention to any particular embodiment, but it should be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0028] In the present invention, terms such as "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and may be understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0029] In addition, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion in between. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion in between. In addition, in the present application, being "on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0030] The present invention relates to a battery pack, which in one example includes a base plate, side plates coupled along the edges of the base plate to form an accommodation space therein, a single cross beam coupled to the base plate to collectively partition the inner accommodation space of the base plate laterally, and a plurality of battery cell assemblies mounted in the accommodation space partitioned by the single cross beam, and a guide structure is interposed between the plurality of battery cell assemblies and the single cross beam to regulate the position of each battery cell assembly on an XY plane corresponding to the surface of the base plate.

[0031] In the battery pack of the present invention having such a structure, the storage space inside the pack case is divided by a single cross beam, and the single cross beam is connected as one across the entire lateral direction of the pack case. Therefore, there is no center beam configuration, which simplifies the assembly process of the battery pack, reduces the number of parts, and reduces the weight of the battery pack. Space utilization rate is improved, while the single cross beam can maintain good rigidity of the pack case.

[0032] In addition, the guide structure interposed between the plurality of battery cell assemblies and the single cross beam accurately regulates the installation position of the plurality of battery cell assemblies when they are mounted between a pair of single cross beams.

[0033] Hereinafter, a specific embodiment of the battery pack 10 according to the present invention will be described in detail with reference to the accompanying drawings. For reference, the directions of front / rear, up / down, left / right, and the like used in the following description to specify relative positions are intended to aid in understanding the invention, and unless otherwise specified, are based on the directions shown in the drawings.

[0034] (First embodiment) Fig. 1 is a diagram showing an overall internal structure of a battery pack 10 according to an embodiment of the present invention, and Fig. 2 is a diagram showing a structure in which battery cell assemblies 200 are mounted in a pack case 100. The battery pack 10 of the present invention includes a pack case 100 and a plurality of battery cell assemblies 200 mounted in the pack case 100.

[0035] The pack case 100 includes a base plate 110, side plates 120 that are connected along the edges of the base plate 110 to form an accommodation space therein, and a single cross beam 130 that is connected to the base plate 110 so as to horizontally and collectively partition the accommodation space inside the base plate 110. Here, the single cross beam 130 refers to a cross beam that is connected seamlessly across the entire width of the side plate 120 in the horizontal direction (X-axis direction in the drawing), and the single cross beam 130 ensures good rigidity against lateral loads even without an additional partition such as a center beam.

[0036] A plurality of battery cell assemblies 200 are mounted in the accommodation space partitioned horizontally by the single cross beam 130. As shown in the drawings, since there is no vertical partition such as a center beam inside the pack case 100 of the present invention, a space exists between adjacent battery cell assemblies 200. For example, when two battery cell assemblies 200 are arranged horizontally as in the illustrated embodiment, there is a surplus space in the central region of the pack case 100 to allow for electrical wiring and the like. Therefore, instead of the module housing or center beam provided in the conventional battery pack 10, a means for regulating the position between the battery cell assemblies 200 sharing the same accommodation space is required.

[0037] To this end, the battery pack 10 of the present invention includes a guide structure 300 interposed between the multiple battery cell assemblies 200 and the single cross beam 130, and the guide structure 300 regulates the position of each battery cell assembly 200 on the XY plane corresponding to the surface of the base plate 110.

[0038] FIG. 3 is an enlarged view showing the structure of the guide structure 300 interposed between the battery cell assembly 200 and the single cross beam 130, and shows the guide structures 300 provided on the battery cell assembly 200 and the single cross beam 130 separately.

[0039] 3, each battery cell assembly 200 includes a plurality of cell stacks 210 and a bus bar frame assembly 220 that is mechanically and electrically coupled to the plurality of cell stacks 210 at both lateral ends from which the leads 212 of the cell stacks 210 protrude. The guide structure 300 on the battery cell assembly 200 side is a protruding guide rib 320, which is provided, for example, on a side surface of the bus bar frame assembly 220. Correspondingly, the guide structure 300 on the single cross beam 130 side is provided as a guide slot 310 formed in a concave shape along the height direction (the Z-axis direction in the drawing).

[0040] For reference, in this specification, a secondary battery having a plurality of positive electrodes and negative electrodes, a separator layer between the positive electrodes and negative electrodes, and a lead 212 electrically connecting each electrode tab provided on the positive electrodes and negative electrodes is referred to as a cell stack 210. That is, the cell stack 210 refers to a completed secondary battery that can be repeatedly charged and discharged, and is not limited to a form such as a pouch-type battery or a square-type battery. The battery cell assembly 200 corresponds to the concept of a module in which a plurality of such cell stacks 210 are assembled, and a bundle of cell stacks 210 is mechanically restrained and electrically connected by bus bar frame assemblies 220 at both front and rear ends.

[0041] FIG. 4 is a diagram showing a structure in which a battery cell assembly 200 is coupled to a single cross beam 130 via a guide structure 300. The battery cell assembly 200 is mounted in the pack case 100 with both sides facing the single cross beam 130, in other words, with the bus bar frame assemblies 220 at both front and rear ends facing the vertical direction (Y direction in the drawing). The distance between the parallel single cross beams 130 corresponds to the overall width of the battery cell assembly 200. Thus, in order to insert the battery cell assembly 200 between a pair of single cross beams 130, the guide rib 320 of the battery cell assembly 200 must be aligned with the guide slot 310 of the single cross beam 130. Therefore, the mounting position of each battery cell assembly 200 with respect to the base plate 110 is accurately regulated.

[0042] In addition, since the guide slots 310 and the guide ribs 320 are formed along the Z-axis direction, the movement of the battery cell assemblies 200 on the XY plane defined by the base plate 110 is restricted. In other words, with the guide structure 300 interposed, the battery cell assemblies 200 can only move in the insertion direction and cannot move on the base plate 110. Therefore, the mounting position of each battery cell assembly 200 on the base plate 110 is firmly fixed by the guide structure 300.

[0043] In order to accurately and firmly regulate the position of the battery cell assembly 200, the guide structures 300 may be provided at the four corners of the battery cell assembly 200. The guide slots 310 may be formed over the entire height of the single cross beam 130, while the guide ribs 320 may be formed over at least a portion of the entire height along the side of the bus bar frame assembly 220. By forming the guide ribs 320 over a portion of the height of the bus bar frame assembly 220, good accessibility to the terminals 222 provided on the bus bar frame assembly 220 may be ensured. In this case, it is preferable that the guide ribs 320 extend from the lower end of the bus bar frame assembly 220, because this is advantageous in determining the initial insertion position of the single cross beam 130 into the guide slots 310.

[0044] Second embodiment The guide structure 300 according to the first embodiment effectively restricts the position of the battery cell assembly 200 on the XY plane relative to the pack case 100. In addition, in the second embodiment, an embodiment of a fixing structure 400 that can restrain the battery cell assembly 200 in the Z-axis direction will be described.

[0045] A fixing structure 400 for restricting the position of the battery cell assembly 200 in the Z-axis direction is also provided between the battery cell assembly 200 and the single cross beam 130. Fig. 5 is a view showing the structure of the fixing structure 400 interposed between the battery cell assembly 200 and the single cross beam 130, Fig. 6 is a view showing the fixing structure 400 provided on the battery cell assembly 200, and Fig. 7 is a view showing the fixing structure 400 provided on the single cross beam 130. As shown in the drawings, the fixing structure 400 includes a first groove 410 formed in a concave shape on the lower part of the single cross beam 130, and a first hook 412 provided on the bus bar frame assembly 220 to engage with the first groove 410.

[0046] In one embodiment of the present invention, the first hook 412 is an elastic hook that operates elastically, and the first groove 410 and the first hook 412 form a snap-fit ​​joint 414. That is, when the guide rib 320 of the battery cell assembly 200 is fitted into the guide slot 310 on the pair of single cross beams 130, the first hook 412, which is an elastic hook with a cantilever structure, slides on the surface of the single cross beam 130 in a slightly retreated state, and when the first hook 412 matches the first groove 410, it elastically returns to its original state, and a snap-fit ​​joint 414 is formed in which the wedge end of the first hook 412 is caught in the upper step of the first groove 410.

[0047] Fig. 8 is a rear view of the structure of the fixing structure 400 in Fig. 5, and Fig. 10 is a cross-sectional view of part "A" in Fig. 8, in which the first hook 412 is caught in the upper step of the first groove 410 by a snap-fit ​​action, and the movement of the battery cell assembly 200 in the (+)Z axis direction is restricted as shown in the figure. In other words, the first hook 412 and the first groove 410 prevent the battery cell assembly 200 mounted in the single cross beam 130 from coming off upward.

[0048] The fixing structure 400 may further include a second groove 420 formed in a concave shape on an upper portion of the single cross beam 130, and a second hook 422 provided on the bus bar frame assembly 220 to contact a step of the second groove 420. In the illustrated embodiment, the second groove 420 is an open groove that is open at the top, and the second hook 422 is configured as a rigid hook that contacts a lower step of the second groove 420 to support the battery cell assembly 200.

[0049] If the first hook 412 and the first groove 410 are intended to restrict movement of the battery cell assembly 200 in the (+)Z-axis direction, the second hook 422 and the second groove 420 are intended to restrict movement of the battery cell assembly 200 in the (-)Z-axis direction. Fig. 9 is a top view of the structure of the fixing structure 400 in Fig. 5, and Fig. 11 is a cross-sectional view of part "B" in Fig. 8, in which the inner surface of the wedge end of the second hook 422 is configured to hook onto the lower step of the second groove 420, and this hooking action prevents the battery cell assembly 200 from moving further downward, i.e., in the (-)Z-axis direction.

[0050] Even if downward pressure acts on the battery cell assembly 200, the second hook 422 and the second groove 420 prevent the battery cell assembly 200 from being pressed by the base plate 110. In particular, when the battery cell assembly 200 is mounted in the pack case 100 as a cell-to-pack structure without a separate module housing, there is no frame structure to protect the bottom surface of the battery cell assembly 200, so the second hook 422 and the second groove 420 are useful in preventing the bottom of the battery cell assembly 200 from being damaged by an external force.

[0051] In the illustrated embodiment, the second groove 420 is configured as an upward open groove and the second hook 422 is configured as a rigid hook, because this is more advantageous in enhancing the downward protection function of such a battery cell assembly 200, but the second hook 422 and the second groove 420 may also be configured as a snap-fit ​​joint if movement in the (-)Z axis direction can be limited.

[0052] 6 to 9, the first groove 410 and the second groove 420 may be arranged separately from each other on the inside and outside of the guide slot 310. The separated arrangement of the first groove 410 and the second groove 420 results in the corresponding separated arrangement of the first hook 412 and the second hook 422. Such a separated arrangement of the fixing structure 400 not only does not hinder the binding action of the first hook 412 and the second hook 422, but also distributes the points of application of force in the Z-axis direction, thereby more stably restricting the position of the battery cell assembly 200.

[0053] For example, the first hook 412 may be disposed closer to the outer periphery of the battery cell assembly 200 than the second hook 422. This is because it is more stable for the first hook 412, which is an elastic hook that undergoes deformation, to restrain the battery cell assembly 200 over as wide an area as possible. The first hook 412 and the second hook 422 may be disposed on the side of the bus bar frame assembly 220 together with the guide rib 320. As the guide structure 300 and the fixing structure 400 are disposed on the side of the bus bar frame assembly 220, the structural design of the bus bar frame assembly 220 is simplified, and the accessibility to the terminals 222 and various insulation and protection designs are improved.

[0054] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments, etc. in this specification are merely one embodiment of the present invention and do not fully represent the technical ideas of the present invention, and therefore there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0055] 10: Battery pack 100: Pack case 110: Base plate 120: Side plate 130: Single cross beam 200: Battery cell assembly 210: Cell stack 220: Busbar frame assembly 222: Terminal 300: Guide Structure 310: Guide slot 320: Guide rib 400: Fixed structure 410: 1st groove 412: First Hook 414: Snap fit joint 420:Second groove 422: 2nd hook

Claims

1. A base plate; a side plate coupled along an edge of the base plate, the side plate forming an accommodation space therein; a single cross beam coupled to the base plate so as to laterally and collectively divide an inner storage space of the base plate; a plurality of battery cell assemblies mounted in an accommodation space defined by the single cross beam; A battery pack, wherein a guide structure is interposed between the plurality of battery cell assemblies and the single cross beam, the guide structure regulating the position of each of the battery cell assemblies on an XY plane corresponding to the surface of the base plate.

2. The battery cell assembly includes: a bus bar frame assembly that mechanically and electrically couples the cell stacks to both lateral ends of the cell stacks from which the leads protrude, The guide structure includes:

2. The battery pack according to claim 1, further comprising: a guide slot formed concavely along a height direction of the single cross beam; and a guide rib provided on the bus bar frame assembly to be guided along the guide slot.

3. The guide structure includes: The battery pack according to claim 1 or 2, wherein the battery pack is provided at four corners of the battery cell assembly.

4. the guide slots are formed across the entire height of the single cross beam; The battery pack according to claim 2 , wherein the guide rib is formed along a side surface of the bus bar frame assembly over at least a portion of the overall height.

5. The battery pack according to claim 2 , wherein a fixed structure is interposed between the plurality of battery cell assemblies and the single cross beam, the fixed structure restricting the position of each of the battery cell assemblies on the Z axis.

6. The fixed structure includes: a first groove formed in a concave shape in a lower portion of the single cross beam; The battery pack according to claim 5 , further comprising a first hook provided on the bus bar frame assembly to engage with the first groove.

7. The first hook is an elastic hook that operates elastically, The battery pack of claim 6 , wherein the first groove and the first hook form a snap-fit ​​joint.

8. The fixed structure includes: a second groove formed in a concave shape on an upper portion of the single cross beam; The battery pack according to claim 6 , further comprising: a second hook provided on the bus bar frame assembly to contact a step of the second groove.

9. The second groove is an open groove having an upper portion open thereto, The battery pack according to claim 8 , wherein the second hook is a rigid hook that contacts a lower step of the second groove to support the battery cell assembly.

10. The battery pack according to claim 8 , wherein the first groove and the second groove are disposed separated from each other on an inside and an outside of the guide slot as a boundary.

11. The battery pack according to claim 10 , wherein the first hook is disposed closer to an outer periphery of the battery cell assembly than the second hook.

12. The battery pack according to claim 8 , wherein the first hook and the second hook are disposed on a side surface of the bus bar frame assembly together with the guide rib.

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