Title of Invention: Battery pack having improved fastening structure and automobile including same
technical field
[One]
The present invention relates to a battery pack having an improved fastening structure and an automobile including the same, and more particularly, by fastening a module stack and a pack housing with bolts at once to increase connection reliability and reduce costs, but It relates to a battery pack having a structure capable of preventing moisture penetration through a fastening portion, and an automobile including the same.
[2]
This application is a priority claim application for Korean Patent Application No. 10-2020-0000994 filed on January 3, 2020, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
background
[3]
Secondary batteries that are easy to apply according to product groups and have electrical characteristics such as high energy density are not only portable devices, but also electric vehicles (EVs) or hybrid vehicles (HEVs) driven by an electric drive source. It is universally applied. These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency in that not only the primary advantage of being able to dramatically reduce the use of fossil fuels, but also the fact that no by-products are generated from the use of energy.
[4]
The types of secondary batteries currently widely used include a lithium ion battery, a lithium polymer battery, a nickel cadmium battery, a nickel hydride battery, a nickel zinc battery, and the like. The unit secondary battery cell, that is, the operating voltage of the unit battery cell is about 2.5V ~ 4.5V. Accordingly, when a higher output voltage is required, a plurality of battery cells are connected in series to form a battery pack. In addition, a plurality of battery cells may be connected in parallel to form a battery pack according to the charge/discharge capacity required for the battery pack. Accordingly, the number of battery cells included in the battery pack may be variously set according to a required output voltage or charge/discharge capacity.
[5]
On the other hand, when configuring a battery pack by connecting a plurality of battery cells in series/parallel, a battery module including a plurality of battery cells is first configured, and a module stack formed by stacking a plurality of these battery modules is accommodated in the pack housing. It is common to configure the battery pack by
[6]
Accordingly, there is a need to reduce component costs and improve structural reliability through development of a battery pack having a structure in which fastening between a plurality of battery modules and fastening between the module stack and the pack housing can be made as simple as possible.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[7]
The present invention was created in consideration of the above-described technical problem, and by making the fastening between a plurality of battery modules and the fastening between the module stack and the pack housing formed by stacking the plurality of battery modules as simple as possible, the reduction of parts and the process An object of the present invention is to realize the simplification of
[8]
However, the technical problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.
means of solving the problem
[9]
A battery pack according to an embodiment of the present invention for solving the above-described problems, a plurality of battery modules are stacked module stack; a pack housing including a lower housing supporting the module stack from a lower portion and an upper housing coupled to the lower housing from an upper portion of the module stack; a plurality of weld nuts fixed to a lower surface of the lower housing; and a plurality of fastening bolts that pass through the pack housing and the module stack and are fastened to the weld nut. includes
[10]
The lower housing may include a lower housing body providing an accommodating space for the module stack; and an airtight plate assembly attached to a lower surface of the lower housing body and providing an accommodation space for the weld nut. may include
[11]
The airtight plate assembly may include: a gasket covering the weld nut; and an airtight plate that presses the gasket and is attached to a lower surface of the lower housing. may include.
[12]
The airtight plate may have a double step structure having an accommodation space in which the gasket can be accommodated and a space in which the weld nut can be accommodated.
[13]
An attachment groove to which the airtight plate assembly may be attached may be formed on a lower surface of the lower housing body.
[14]
The depth of the attachment groove may be equal to or deeper than the height of the step of the airtight plate.
[15]
A sealing member may be coated on the head portion of the fastening bolt.
[16]
The battery module may include: a unit module stack formed by combining a plurality of unit modules; and a BMS assembly coupled to one side in the longitudinal direction of the unit module stack. may include.
[17]
The BMS assembly includes a plurality of first fastening holes formed along a height direction, and the unit module includes a plurality of second fastening holes formed on one side in the longitudinal direction and a third fastening hole formed on the other side in the longitudinal direction. Hall may be provided.
[18]
Among the plurality of fastening bolts, a first fastening bolt simultaneously passes through the overlapping first through-hole and second through-hole, and a second fastening bolt simultaneously passes through the overlapping second through-hole and third through-hole to form a pack. The housing, the BMS assembly, and the unit module stack can be combined at once.
[19]
The unit module has a structure in which a plurality of cell groups including a plurality of battery cells arranged along a length direction of the unit module are arranged along a width direction of the unit module, and the third fastening hole includes adjacent cells. It may be formed in a dead space that is generated as the groups are staggered.
[20]
[21]
Meanwhile, a vehicle according to an embodiment of the present invention for solving the above-described problems includes the battery pack according to an embodiment of the present invention as described above.
Effects of the Invention
[22]
According to one aspect of the present invention, the reduction of parts and the simplification of the process are realized by making the fastening between the plurality of battery modules and the fastening between the module stacking and the pack housing formed by stacking the plurality of battery modules as simple as possible, and also It improves energy density and improves structural reliability.
Brief description of the drawing
[23]
The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the detailed description of the present invention to be described later, so that the present invention is described in such drawings should not be construed as being limited only to
[24]
1 is a complete perspective view of a battery pack according to an embodiment of the present invention.
[25]
FIG. 2 is an exploded perspective view of the battery pack shown in FIG. 1 ;
[26]
FIG. 3 is a view showing a lower surface of a pack housing applied to the battery pack shown in FIG. 1 well.
[27]
FIG. 4 is a view showing the internal structure of area A of FIG. 3 .
[28]
FIG. 5 is a view illustrating a state in which the module housing is removed from the battery module applied to the battery pack shown in FIG. 1 .
[29]
FIG. 6 is a view showing the battery cells accommodated in the cell housing in the battery module shown in FIG. 5 .
[30]
7 is an exploded perspective view of a lower housing constituting a pack housing applied to the present invention.
[31]
FIG. 8 is a view showing a cross-section taken along line XX of FIG. 1 .
[32]
FIG. 9 is an enlarged view of area B of FIG. 8 .
[33]
10 is a view showing a fastening bolt applied to the present invention.
Modes for carrying out the invention
[34]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention. Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that there may be equivalents and variations.
[35]
[36]
First, a schematic structure of the battery pack 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4 .
[37]
1 to 4 , a battery pack 1 according to an embodiment of the present invention includes a module stack M, a pack housing 200, a plurality of fastening bolts 300 and a plurality of weld nuts. nut) (400).
[38]
As shown in FIG. 2 , the module stack M has a form in which a plurality of battery modules 100 are stacked. A detailed structure of each battery module 100 will be described later in detail with reference to FIGS. 5 and 6 .
[39]
As shown in FIG. 2 , the pack housing 200 covers the lower housing 210 supporting the lower portion of the module stack M and the upper part of the module stack M and is attached to the lower housing 210 . It includes an upper housing 220 that is coupled. The lower housing 210 has a special structure on its lower surface. The special structure of the lower housing 210 will be described later in detail.
[40]
As shown in FIGS. 1 and 2 , the plurality of fastening bolts 300 have a long bolt shape, and include an upper housing 220 , a module stack body M and a lower housing 210 . It passes through in turn so that the module stack (M) can be fixed to the pack housing (200).
[41]
As shown in FIG. 4 , the weld nut 400 is attached to the bottom surface of the lower housing 210 (see FIGS. 2 and 3 ) by welding. The weld nut 400 is attached to a position corresponding to the through hole formed in the bottom surface of the lower housing 210 so as to be coupled to the fastening bolt 300 . In addition, the weld nut 400 is located inside the gasket 210a and the airtight plate 210b constituting the lower housing 210 . The weld nut 400 is positioned inside the gasket 210a and the airtight plate 210b as described above, so that external foreign substances or moisture due to the through hole formed in the lower housing 210 penetrate into the inside of the pack housing 200 . This is to prevent shortening of the lifespan of the battery pack 1 or causing deterioration in performance.
[42]
[43]
Next, with reference to FIGS. 5 and 6 along with FIG. 2 , the battery module 100 constituting the module stack M applied to the present invention will be described in detail.
[44]
The battery module 100 shown in FIG. 5 is a type in which the external cover, that is, the module housing, is removed from the battery module 100 shown in FIG. 2 . That is, the battery module 100 shown in FIG. 5 and the battery module 100 shown in FIG. 2 have the same reference numerals for convenience of description, although there is a difference in the presence/absence of the module housing.
[45]
5 and 6 , the battery module 100 includes a unit module stack 110 formed by combining a plurality of unit modules 111 and a longitudinal direction (in FIG. 5 ) of the unit module stack 110 and the end module stack 110 . It includes a BMS assembly 120 coupled to one end (in the direction parallel to the X-axis).
[46]
The unit module 111 includes a cell housing 111a and a plurality of battery cells 111b accommodated in the cell housing 111a and electrically connected to each other. As the battery cell 111b, for example, a cylindrical battery cell may be applied.
[47]
The BMS assembly 120 includes a plurality of battery management system (BMS) 121 and a BMS frame 122 surrounding and fixing the BMS 121 . Each BMS 121 is electrically connected to the unit module 111 and may act as a slave BMS. That is, the plurality of BMSs 121 may be connected to a separate master BMS (not shown).
[48]
The battery module 100 includes a plurality of fastening holes H1 to H3 through which the fastening bolt 300 (see FIGS. 1 and 2 ) can pass. Specifically, the BMS frame 122 includes a plurality of first fastening holes H1 formed to be spaced apart from each other along the width direction (parallel to the Y axis of FIG. 5 ) of the battery module 100 . In addition, the unit module 111 is formed at one end of the unit module 111 in the longitudinal direction (in a direction parallel to the X axis in FIG. 5 ) and in the width direction (parallel to the Y axis in FIG. 5 ) of the unit module 111 . direction) and a plurality of second fastening holes H2 formed to be spaced apart from each other. The second fastening hole H2 is formed in the cell housing 111a constituting the unit module 111 . That is, the second fastening hole H2 is formed in an excess space other than the accommodating space of the battery cell 111b in the cell housing 111a. When assembling the unit module stack 110 and the BMS assembly 120 for forming the battery module 100 , the first fastening hole H1 and the second fastening hole H2 overlap each other. Accordingly, the fastening bolt 300 passes through the first fastening hole H1 and the second fastening hole H2 at the same time, and thus the unit module stack 110 , the BMS assembly 120 , and the pack housing 200 . ) are combined together.
[49]
In addition, the unit module 111 is formed at the other end of the unit module 111 in the longitudinal direction (in a direction parallel to the X axis in FIG. 5 ) and in the width direction (parallel to the Y axis in FIG. 5 ) of the unit module 111 . direction) and a plurality of third fastening holes H3 formed to be spaced apart from each other. The third fastening hole H3 is formed in the cell housing 111a constituting the unit module 111 . That is, the third fastening hole H3 is formed in an excess space other than the accommodating space of the battery cell 111b in the cell housing 111a. When assembling the unit module 111 and the unit module 111 for forming the unit module stack 110 , the second fastening hole H2 and the third fastening hole H3 overlap each other. Accordingly, the fastening bolt 300 passes through the second fastening hole H2 and the third fastening hole H3 at the same time, whereby the unit module stack 110 and the pack housing 200 are coupled together at once. do.
[50]
On the other hand, referring to FIG. 6 , a third fastening hole ( In the case of H3), it is formed using a dead space generated by staggered arrangement of cell groups G adjacent to each other. That is, the unit module 111 includes a cell group G including a plurality of battery cells 111b arranged along the longitudinal direction of the unit module 111 (a direction parallel to the X-axis of FIG. 6 ). (111) has a structure arranged in plurality along the width direction (parallel to the Y-axis in FIG. 6), and the third fastening hole H3 is a dead space generated when adjacent cell groups G are alternately arranged. will be formed Since the third fastening hole H3 is formed using the dead space as described above, loss of energy density due to the formation of the third fastening hole H3 can be prevented.
[51]
[52]
Next, with reference to FIGS. 7 to 10 together with FIG. 4 , the hermetic plate assembly 212 , the fastening bolt 300 and the weld nut 400 applied to the battery pack 1 according to an embodiment of the present invention. The fastening structure using the , and the effect of improving fastening properties and improving airtightness accordingly will be described in detail.
[53]
First, referring to FIGS. 7 to 10 together with FIG. 4 , the lower housing 210 includes a lower housing body 211 and an airtight plate assembly 212 . The airtight plate assembly 212 is inserted into the attachment groove 211a formed on the lower surface of the lower housing body 211 and is fixed to the inner bottom surface of the attachment groove 211a by welding or the like.
[54]
The hermetic plate assembly 212 includes a gasket 212a and a hermetic plate 212b. The gasket 212a surrounds the periphery of the weld nut 400 attached to the lower surface of the lower housing body 211 by welding, and is interposed between the weld nut 400 and the airtight plate 212b. It prevents foreign substances and/or moisture from penetrating into the gap between the bottom surface of the lower housing body 211 and the lower housing body 211 . The airtight plate 212b is fixed to the bottom surface of the lower housing body 211 by welding or the like while covering the gasket 212a and the weld nut 400 within the attachment groove 211b to primarily contain foreign substances and/or moisture. to prevent penetration of
[55]
The airtight plate 212b presses the gasket 212a and is attached to the lower surface of the lower housing 210 , that is, the bottom surface of the housing body 211 . In addition, the airtight plate 212b may have a double step structure having an accommodating space in which the gasket 212a can be accommodated and an accommodating space in which the weld nut 400 can be accommodated. However, it is preferable that the depth of the attachment groove 211a is equal to or deeper than the height of the airtight plate 212b according to the double step structure. This is to prevent loss of energy density due to the formation of the airtight plate 212b.
[56]
On the other hand, referring to FIG. 10 , the fastening bolt 300 minimizes penetration of foreign substances and/or moisture through the through hole formed in the upper portion of the pack housing 200 , that is, the through hole formed in the upper housing 210 . For this, a sealing member (S) coated on the surface of the head may be provided. The sealing member S is preferably a material having elasticity, for example, a urethane material may be used.
[57]
[58]
As described above, the battery pack 1 according to an embodiment of the present invention includes the weld nut 400 fixed in advance to the pack housing 200 , and the pack housing 200 and the module stack M at once. Reliability of fastening by having a structure capable of fastening each component constituting the module stack M and the pack housing 200 at once using a fastening bolt 300 that penetrates and is fastened to the weld nut 400 improvement and cost savings.
[59]
In addition, the battery pack 1 according to an embodiment of the present invention has a structure capable of preventing the penetration of foreign substances and/or moisture through the hole formed on the outside of the pack housing 200 , It can reduce the concern of performance degradation in the process of use.
[60]
[61]
Meanwhile, a vehicle according to an embodiment of the present invention includes the battery pack according to an embodiment of the present invention, as described above.
[62]
[63]
In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and will be described below with the technical idea of ​​the present invention by those of ordinary skill in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims.
Claims
[Claim 1]
a module stack in which a plurality of battery modules are stacked; a pack housing including a lower housing supporting the module stack from a lower portion and an upper housing coupled to the lower housing from an upper portion of the module stack; a plurality of weld nuts fixed to a lower surface of the lower housing; and a plurality of fastening bolts that pass through the pack housing and the module stack and are fastened to the weld nut. A battery pack containing
[Claim 2]
The apparatus of claim 1 , wherein the lower housing comprises: a lower housing body providing an accommodating space for the module stack; and an airtight plate assembly attached to a lower surface of the lower housing body and providing an accommodation space for the weld nut. A battery pack comprising a.
[Claim 3]
3. The method of claim 2, wherein the airtight plate assembly comprises: a gasket covering the weld nut; and an airtight plate that presses the gasket and is attached to a lower surface of the lower housing. A battery pack comprising a.
[Claim 4]
The battery pack according to claim 3, wherein the airtight plate has a double step structure having an accommodating space in which the gasket can be accommodated and a space in which the weld nut can be accommodated.
[Claim 5]
The battery pack according to claim 4, wherein an attachment groove to which the airtight plate assembly can be attached is formed on a lower surface of the lower housing body.
[Claim 6]
The battery pack according to claim 5, wherein a depth of the attachment groove is equal to or deeper than a height of a step of the airtight plate.
[Claim 7]
The battery pack according to claim 1, wherein a sealing member is coated on the head of the fastening bolt.
[Claim 8]
The method of claim 1, wherein the battery module comprises: a unit module stack formed by combining a plurality of unit modules; and a BMS assembly coupled to one side in the longitudinal direction of the unit module stack. A battery pack comprising a.
[Claim 9]
The method according to claim 8, wherein the BMS assembly includes a plurality of first fastening holes formed along a height direction, and the unit module includes a plurality of second fastening holes formed on one side in the longitudinal direction and the other side in the longitudinal direction. A battery pack comprising a third fastening hole formed in the .
[Claim 10]
The method of claim 9, wherein, among the plurality of fastening bolts, a first fastening bolt simultaneously passes through the overlapping first through hole and the second through hole, and the second fastening bolt passes through the overlapping second through hole and the third through hole. A battery pack, characterized in that the pack housing, the BMS assembly, and the unit module stack are combined at once through the hole at the same time.
[Claim 11]
The method of claim 10, wherein the unit module has a structure in which a plurality of cell groups including a plurality of battery cells arranged along a length direction of the unit module are arranged along a width direction of the unit module, and the third fastening The hole is formed in a dead space generated when adjacent cell groups are alternately arranged.
[Claim 12]
12. A motor vehicle comprising a battery pack according to any one of claims 1 to 11.