Battery pack and vehicle including the battery pack

Abstract

A battery pack according to an embodiment of the present invention comprises: a module stack comprising a plurality of battery modules stacked together; a battery pack housing comprising a lower housing arranged on the lower side of the module stack to support the module stack and an upper housing connected to the lower housing from above the module stack; and a plurality of shift plates connected to the inner side of each of the lower housing and the upper housing to elastically press the module stack.

Description

Technical Field

[0001] The present disclosure relates to a battery pack with an improved connection structure and a vehicle including the battery pack, and more specifically, to a battery pack and a vehicle including the battery pack: the battery pack can increase connection reliability and reduce costs by fastening a module stack and a battery pack case together using bolts, and also has a structure in which the battery pack case can maintain a state of pressing the battery module to provide improved stability when vibration occurs in the battery pack. Background Art

[0002] Secondary batteries, which are easily applicable to various product groups and have electrical characteristics such as high energy density, are widely used not only in portable devices but also in electric vehicles (EV) or hybrid electric vehicles (HEV) driven by electric drive sources. Such secondary batteries have attracted attention as new energy sources for environmental friendliness and improved energy efficiency because they do not produce byproducts in energy use and have the main advantage of significantly reducing the use of fossil fuels.

[0003] The types of secondary batteries currently widely used in the art include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. The operating voltage of such a unit secondary battery cell (i.e., unit battery cell) is about 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack can be constructed by connecting a plurality of battery cells in series. In addition, a battery pack can be constructed by connecting a plurality of battery cells in parallel according to the charge / discharge capacity required for the battery pack. Therefore, the number of battery cells included in the battery pack can be set in various ways according to the required output voltage or charge / discharge capacity.

[0004] Meanwhile, when a battery pack is constructed by connecting a plurality of battery cells in series / parallel, generally, a battery module including a plurality of battery cells is first constructed, and a module stack formed by stacking a plurality of such battery modules is accommodated in a pack case to construct the battery pack.

[0005] Therefore, it is necessary to reduce component costs and improve structural reliability by developing a battery pack having a structure in which connections between multiple battery modules and between a module stack and a battery pack housing can be made as simple as possible. In addition, since the battery pack may vibrate, it is necessary to develop a battery pack with improved structural stability. Summary of the invention

[0006] Technical issues

[0007] The present disclosure is intended to solve the problems of the related art, and thus the present disclosure is intended to allow fastening between a plurality of battery modules and between a module stack formed by stacking a plurality of battery modules and a battery pack case to be as simple as possible, and also to improve structural stability.

[0008] However, the technical problems to be solved by the present disclosure are not limited to the above problems, and those skilled in the art will clearly understand other problems not mentioned herein through the following description.

[0009] Technical Solution

[0010] In one aspect of the present disclosure, a battery pack is provided, comprising: a module stack in which a plurality of battery modules are stacked; a battery pack housing having a lower housing configured to support the module stack on its lower side and an upper housing connected to the lower housing from the upper side of the module stack; and a plurality of shift plates, respectively connected to the inner side of the lower housing and the inner side of the upper housing to elastically press the module stack.

[0011] The shift plate may include: a pair of pressing plates configured to face inner surfaces of side walls of the battery pack case; and a connecting plate configured to connect the pair of pressing plates to each other and disposed to face a bottom surface of the battery pack case.

[0012] The pressing plate may include: a supporting portion, which is arranged parallel to the inner surface and contacts the inner surface of the side wall of the battery pack shell; an inclined portion, which is bent to extend from one end of the supporting portion toward the interior of the battery pack shell; and an elastic pressing portion, which is constructed to extend parallel to the supporting portion from one end of the inclined portion away from the supporting portion, and is constructed to press the module stack by an elastic restoring force, and the connecting plate can connect a pair of elastic pressing portions to each other.

[0013] Each of the lower case and the upper case may include a support edge configured to protrude from inner surfaces of the lower case and the upper case to face an inner surface of the elastic pressing portion in a spaced-apart state.

[0014] A curved region between the inclined portion and the elastic pressing portion may have a circular shape.

[0015] The battery pack may further include: a plurality of fastening bolts provided to penetrate the battery pack case and the module stack; and a plurality of welding nuts fixed to a lower surface of the lower case and coupled with the fastening bolts.

[0016] The battery pack may further include a gas-tight plate assembly attached to a lower surface of the lower case and configured to provide an accommodation space for the welding nut.

[0017] The airtight plate assembly may include a gasket configured to cover the welding nut; and a gastight plate configured to press the gasket and be attached to a lower surface of the lower case.

[0018] The airtight plate may have a double-step structure that provides a space for accommodating a gasket and a space for accommodating a weld nut.

[0019] An attaching groove may be formed at a lower surface of the lower case so that the airtight plate assembly is attached to the attaching groove.

[0020] The depth of the attachment groove may be equal to or greater than the height of the step of the airtight plate.

[0021] The head of the fastening bolt may be coated with a sealing member.

[0022] Meanwhile, in another aspect of the present disclosure, a vehicle including the battery pack according to the embodiment of the present disclosure is also provided.

[0023] Technical Effects

[0024] According to an embodiment of the present disclosure, fastening between a plurality of battery modules and between a module stack formed by stacking a plurality of battery modules and a battery pack case can be made as simple as possible, and structural stability of the battery pack can be improved when vibration / impact is applied thereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are used to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not interpreted as being limited to the accompanying drawings.

[0026] Figure 1 is a perspective view showing a battery pack according to an embodiment of the present disclosure.

[0027] Figure 2 It shows Figure 1 An exploded perspective view of a battery pack.

[0028] Figure 3 is an exploded perspective view showing a lower case employed at a battery pack case applied to the present disclosure.

[0029] Figure 4 is an exploded perspective view showing an upper case employed at a battery pack case applied to the present disclosure.

[0030] Figure 5 is shown along Figure 1 A partial enlarged view of the cross section taken along line XX.

[0031] Figure 6 is a diagram showing a lower surface of a lower case applied to a battery pack according to an embodiment of the present disclosure.

[0032] Figure 7 It shows Figure 6Diagram of the internal structure of region A.

[0033] Figure 8 It shows Figure 6 An exploded perspective view of the lower housing.

[0034] Fig. 9 is shown along Figure 1 A diagram of a cross section taken along line YY.

[0035] Fig.10 It shows Fig. 9 A partial enlarged view of area B.

[0036] Fig.11 is a diagram of a fastening bolt applied to the present disclosure. DETAILED DESCRIPTION

[0037] Hereinafter, the preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general and dictionary meanings, but should be interpreted based on the meaning and concept corresponding to the technical solution of the present disclosure on the basis of the principle that the inventor is allowed to appropriately define the terms to obtain the best interpretation. Therefore, the description proposed herein is only a preferred example for illustrative purposes and is not intended to limit the scope of the present disclosure, and it should be understood that other equivalent substitutions and modifications may be made without departing from the scope of the present disclosure.

[0038] First, refer to Figures 1 to 4 A schematic structure of a battery pack 1 according to an embodiment of the present disclosure is described.

[0039] Reference Figures 1 to 4 , the battery pack 1 according to the embodiment of the present disclosure includes a module stack body M, a pack case 200 , a plurality of fastening bolts 300 , and a plurality of shift plates 400 .

[0040] like Figure 2 As shown, the module stack M has a form in which a plurality of battery modules 100 are stacked. Although not specifically shown in the figure, each battery module 100 may include a plurality of battery cells electrically connected to each other, and may further include a plurality of BMSs for grouping the plurality of battery cells and managing charge and discharge of each group.

[0041] like Figure 2 As shown, the battery pack case 200 includes a lower case 210 for supporting a lower portion of the module stack M and an upper case 220 for covering an upper portion of the module stack M and coupled to the lower case 210 .

[0042] like Figure 1 and Figure 2As shown, the plurality of fastening bolts 300 have a long bolt shape and may sequentially pass through the upper case 220, the module stack M, and the lower case 210 so as to fix the module stack M to the battery pack case 200. In addition, the fastening bolts 300 may be used to fasten the plurality of battery modules 100 to each other.

[0043] The shift plate 400 is coupled to the inner sides of the lower housing 210 and the upper housing 220. When the module stack M is inserted into the battery pack housing 200, the shift plate 400 can elastically press the module stack M to minimize the movement of the module stack M within the battery pack housing 200. Considering the function of the shift plate 400, the shift plate 400 can be moved along the longitudinal direction of the battery pack 1 (parallel to the longitudinal direction of the battery pack 1). Figure 1 and Figure 2 A plurality of fixing members are provided (in the direction of the X-axis) to stably fix the module stack M.

[0044] The following will refer to Figure 5 Together with Figures 1 to 4 A more specific structure and function of the shift plate 400 are described in detail.

[0045] Reference Figures 1 to 5 , the shift plate 400 includes a pair of pressing plates 410 configured to face the inner surface of the side wall of the battery pack case 200 and a connecting plate 420 configured to connect the pair of pressing plates 410 to each other and face the bottom surface of the battery pack case 200. The pair of pressing plates 410 are in contact with both side surfaces of the module stack M to press the module stack M, and the connecting plate 420 is fixed to the bottom surface of the battery pack case 200 by welding and / or bolting to restrict the movement of the module stack M.

[0046] Here, the bottom surface of the battery pack housing 200 refers to a portion parallel to the Figure 1 and Figure 2 The surface of the XY plane, and refers to a surface facing the lower surface of the module stack M among the inner surfaces of the lower shell 210 and a surface facing the upper surface of the module stack M among the inner surfaces of the upper shell 220.

[0047] Reference Figure 5 The pressing plate 410 includes a supporting portion 411, an inclined portion 412, and an elastic pressing portion 413 connected to each other as one body. The supporting portion 411 contacts the inner surface of the side wall of the battery pack housing 200 and is arranged parallel to the inner surface. The inclined portion 412 is bent to extend from one end of the supporting portion 411 toward the inside of the battery pack housing 200. The elastic pressing portion 413 extends from one end of the inclined portion 412 away from the supporting portion 411 in parallel with the supporting portion 411 and presses the module stack M by elastic restoring force.

[0048] Due to the inclined portion 412, a gap is generated between the elastic pressing portion 413 and the inner surface of the side wall of the battery pack case 200, and this gap can bend the elastic pressing portion 413 when the module stack M is inserted. This bending of the elastic pressing portion 413 generates an elastic restoring force, so the pair of elastic pressing portions 413 located on both sides of the module stack M presses the module stack M toward the center of the battery pack 1.

[0049] In order to realize the elastic pressing action of the elastic pressing portion 413, the width between the pair of elastic pressing portions 413 facing each other is preferably equal to or slightly smaller than the width of the module stack M (in the direction parallel to the Figure 1 and Figure 2 In addition, considering the ease of insertion of the module stack M, the width between the pair of supporting portions 411 facing each other is preferably slightly larger than the width of the module stack M.

[0050] In addition, the curved area between the inclined portion 412 and the elastic pressing portion 413 may have a circular shape. In this case, when inserting the module stack M, the risk of damaging the module stack M caused by the contact between the module stack M and the pressing plate 410 can be minimized, and smoother insertion is possible.

[0051] Meanwhile, the battery pack housing 200 may include a plurality of support beads 211, 221 protruding from the inner surface of one side thereof. Specifically, the lower housing 210 includes a plurality of first support beads 211 protruding from the inner surface thereof and facing the inner surface of the elastic pressing portion 413 in a spaced-apart state. Similarly, the upper housing 220 includes a plurality of second support beads 221 protruding from the inner surface thereof and facing the inner surface of the elastic pressing portion 413 in a spaced-apart state.

[0052] The support edges 211 and 221 are provided to prevent the elastic pressing portion 413 from being excessively deformed. The battery pack for a vehicle is often exposed to continuous vibration and impact during use. When such vibration and impact occur, the elastic pressing portion 413 of the shift plate 400 causes bending deformation to serve as a buffer member to mitigate the impact applied to the module stack M.

[0053] The distance d between the supporting edges 211, 221 and the elastic pressing portion 413 after insertion into the module stack M may be determined in consideration of the weight and size of the battery pack 1 and the expected maximum vibration to be applied to the application. That is, the height of the supporting edges 211, 221 and / or the bending angle of the inclined portion 412 may be determined in consideration of these factors.

[0054] Next, we will refer to Figures 6 to 11 A gastight structure that may be selectively applied to the battery pack 1 according to an embodiment of the present disclosure is described.

[0055] The battery pack 1 according to the embodiment of the present disclosure may include a weld nut 500 and an airtight plate assembly 600 in addition to the above-mentioned components, and may further include a sealing member S coated on the fastening bolt 300 .

[0056] like Figure 7 As shown, the weld nut 500 is attached to the lower housing 210 by welding (see Figure 2 and Figure 3 ) on the bottom surface of the lower case 210. The welding nut 500 is attached at a position corresponding to the through hole formed in the bottom surface of the lower case 210 to be coupled with the fastening bolt 300. In addition, the welding nut 500 is located inside the gasket 610 and the airtight plate 620 attached to the lower case 210. The welding nut 500 is located inside the gasket 610 and the airtight plate 620 as above to prevent external foreign matter or moisture from penetrating into the inside of the battery pack case 200 due to the through hole formed in the lower case 210, thereby shortening the life of the battery pack 1 or deteriorating the performance of the battery pack 1.

[0057] The airtight plate assembly 600 is inserted into the attachment groove 210a formed at the lower surface of the lower shell 210, and is fixed to the inner bottom surface of the attachment groove 210a by welding or the like. The airtight plate assembly 600 includes a gasket 610 and an airtight plate 620. The gasket 610 surrounds the outer periphery of the welding nut 500 attached to the lower surface of the lower shell 210 by welding, and is interposed between the welding nut 500 and the airtight plate 620 to prevent foreign matter or moisture from penetrating into the gap between the welding nut 500 and the bottom surface of the lower shell 210. The airtight plate 620 covers the gasket 610 and the welding nut 500 in the attachment groove 210a, and is fixed to the bottom surface of the lower shell 210 by welding or the like to mainly prevent foreign matter and / or moisture from penetrating.

[0058] The airtight plate 620 presses the gasket 610 and is attached to the lower surface of the lower housing 210. In addition, the airtight plate 620 may have a double-step structure in which a space in which the gasket 610 can be accommodated and a space in which the welding nut 500 can be accommodated are provided. However, according to the double-step structure, the depth of the attachment groove 210a is preferably equal to or greater than the height of the airtight plate 620. This is to prevent energy density loss caused by forming the airtight plate 620.

[0059] At the same time, refer to Fig.11 , the fastening bolt 300 may have a sealing member S coated on the surface of the head thereof to minimize foreign matter and / or moisture infiltrating through a hole formed on the upper portion of the battery pack case 200 (i.e., a through hole formed in the upper case 220). The sealing member S may adopt a material having elasticity, such as a polyurethane material.

[0060] As described above, in the case of the battery pack 1 according to the embodiment of the present disclosure, if vibration and / or impact is applied to the battery pack 1, the shift plate 400 installed at the battery pack case 200 can place the module stack M in the hole to be well fixed in the battery pack case 200 without impact. Therefore, the battery pack 1 according to the embodiment of the present disclosure can have a robustness that is not easily damaged or defective even by vibration and / or impact.

[0061] In addition, since the battery pack 1 according to an embodiment of the present disclosure has a structure in which each component of the module stack M is fastened together with the battery pack housing 200 by using a welding nut 500 pre-fixed to the outside of the battery pack housing 200 and a fastening bolt 300 fastened to the welding nut 500 through the battery pack housing 200 and the module stack M at one time, the fastening reliability can be improved and the manufacturing cost can be reduced.

[0062] In addition, since the battery pack 1 according to an embodiment of the present disclosure has a structure that prevents external foreign matter and / or moisture from penetrating through holes formed on the outside of the pack case 200 , concerns about performance degradation during use of the battery pack may be reduced.

[0063] Meanwhile, a vehicle according to an embodiment of the present disclosure includes the battery pack according to the embodiment of the present disclosure as described above.

[0064] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present disclosure, are given by way of example only, since various changes and modifications within the scope of the present disclosure will be apparent to those skilled in the art from this detailed description.

[0065] This application claims priority from Korean Patent Application No. 10-2020-0000995 filed in Korea on January 3, 2020, the disclosure of which is incorporated herein by reference.

Claims

1. A battery pack, comprising: a module stack in which a plurality of battery modules are stacked; a battery pack case having a lower case for supporting a lower portion of the module stack and an upper case for covering an upper portion of the module stack and coupled to the lower case; and a plurality of shift plates respectively coupled to the inner side of the lower housing and the inner side of the upper housing to elastically press the module stack, wherein each of the lower shell and the upper shell comprises a plurality of support edges configured to protrude from an inner surface of each of the lower shell and the upper shell to prevent the shift plate from being excessively deformed, Wherein, the shift plate comprises: a pair of pressing plates configured to face inner surfaces of the side walls of the battery pack case; and a connecting plate configured to connect the pair of pressing plates to each other and disposed to face the bottom surface of the battery pack case, Wherein, the pressing plate comprises: a support portion, the support portion being arranged parallel to the inner surface and in contact with the inner surface of the side wall of the battery pack housing; an inclined portion bent to extend from one end of the support portion toward the inside of the battery pack case; and an elastic pressing portion configured to extend parallel to the support portion from an end of the inclined portion away from the support portion and configured to press the module stack by an elastic restoring force, The connecting plate connects a pair of elastic pressing parts facing each other.

2. The battery pack according to claim 1, in, The plurality of supporting edges are configured to face the inner surface of the elastic pressing portion in a spaced-apart state.

3. The battery pack according to claim 1, in, A curved area between the inclined portion and the elastic pressing portion has a circular shape.

4. The battery pack according to claim 1, further comprising: a plurality of fastening bolts, the plurality of fastening bolts being arranged to penetrate the battery pack housing and the module stack; as well as A plurality of welding nuts are fixed to the lower surface of the lower housing and coupled with the fastening bolts.

5. The battery pack according to claim 4, further comprising: A gas-tight plate assembly is attached to the lower surface of the lower housing and is configured to provide an accommodation space for the weld nut.

6. The battery pack according to claim 5, in, The airtight plate assembly comprises: a washer configured to surround an outer circumference of the weld nut; and An airtight plate is configured to press the gasket and be attached to the lower surface of the lower case.

7. The battery pack according to claim 6, in, The airtight plate has a double-step structure provided with a space for accommodating the gasket and a space for accommodating the welding nut.

8. The battery pack according to claim 7, in, An attaching groove is formed at the lower surface of the lower case so that the airtight plate assembly is attached to the attaching groove.

9. The battery pack according to claim 8, in, The washer is interposed between the weld nut and the airtight plate, and the airtight plate covers the washer and the weld nut in the attachment groove.

10. The battery pack according to claim 8, in, The depth of the attachment groove is equal to or greater than the height of the step of the airtight plate.

11. The battery pack according to claim 4, in, The head of the fastening bolt is coated with a sealing member.

12. A vehicle comprising a battery pack according to any one of claims 1 to 11.

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