Top-cooled battery pack

Abstract

To provide a battery pack, which may eliminate a risk caused by leakage of cooling water, improve an energy density, and improve the efficiency of an assembly process.SOLUTION: According to one embodiment, there is provided a battery pack which may include: a pack case having a pack tray configured to support a lower portion of battery modules, and a pack cover configured to cover the battery modules and contact a top surface of the battery modules; and a heatsink installed at an upper portion of the pack cover.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a battery pack, and more particularly to a cooling and assembly structure for a battery pack. This application claims priority to Korean Patent Application No. 10-2019-0096284, filed on August 7, 2019, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings. [Background technology]

[0002] Unlike primary batteries, which cannot be recharged, batteries that can be freely charged and discharged are called secondary batteries. These secondary batteries are used not only in small, cutting-edge electronic devices such as mobile phones, personal digital assistants (PDAs), and laptops, but also as power sources for energy storage systems (ESS), electric vehicles (EVs), and hybrid electric vehicles (HEVs).

[0003] Currently, secondary batteries such as lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, and nickel zinc batteries are widely used. The operating voltage of such unit secondary battery cells, i.e., unit battery cells, is about 2.5V to 4.2V. Therefore, when a higher output voltage and energy capacity is required, a battery module is formed by connecting a plurality of battery cells in series, or a battery pack is formed by connecting two or more battery modules in series or in parallel and adding other components. For example, a battery module refers to a device in which a plurality of secondary batteries are connected in series or in parallel, and a battery pack refers to a configuration in which battery modules are connected in series or in parallel to increase capacity and output.

[0004] In addition to the battery module, the battery pack may further include a cooling device for maintaining the temperature of the battery module at an appropriate temperature, a control device for monitoring the operating state of the battery module, and a pack case for packaging these.

[0005] Meanwhile, in the case of battery packs for electric vehicles, the installation space for the battery pack is limited due to the overall length and width of the electric vehicle, so it is important to increase the energy density by mounting components, including the battery module, as efficiently as possible inside the pack case.

[0006] Conventionally, when assembling a battery pack, as shown in Fig. 1, a battery module 2 is placed on the upper surface of a pack tray 1, which corresponds to the bottom surface of a pack case, and the battery module 2 is mechanically fixed to the pack tray 1 by fastening it with bolts. In general, the battery module 2 is fixed to the upper surface of the pack tray 1 by inserting long bolts into a total of four places, namely, the front and rear corners. In addition, for electrical connection between battery modules, a structure is often adopted in which both ends of an inter-bus bar 3 in the form of a metal bar are placed on the upper surfaces of the positive terminal 2a of one battery module 2 and the negative terminal 2b of the other battery module 2, and these are fixed using two bolts.

[0007] Furthermore, the cooling configuration for the battery pack often employs a configuration in which a heat sink 4 is provided on the bottom surface of the pack tray 1, a cooling water supply pipe is connected to it, and cooling water is circulated inside and outside the pack case.

[0008] However, in recent years, several problems have been pointed out with respect to the assembly structure of such a conventional battery pack, including inefficiency in the assembly process due to the excessive number of bolts used to fasten the battery modules and the interbus bars, increased costs, loss of space such as the area indicated by reference character "O" in FIG. 1, reduced energy density due to the provision of a heat sink, leakage of cooling water, and securing sealing reliability for pipes, cooling ports, etc.

[0009] Therefore, there is a need for the development of a battery pack having a cooling and assembly structure capable of solving the above problems. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in consideration of the above problems, and aims to provide a battery pack that can eliminate the dangers caused by cooling water leakage, improve energy density, and make the assembly process more efficient.

[0011] Other objects and advantages of the present invention can be understood from the following description and will become more apparent from the embodiments of the present invention. Also, the objects and advantages of the present invention can be realized by the means and combinations thereof as set forth in the claims. [Means for solving the problem]

[0012] According to one aspect of the present invention, there is provided a battery pack including a plurality of battery modules and a pack case in which the battery modules can be fixedly mounted, A battery pack is provided that includes a pack case having a pack tray that supports a lower portion of a battery module, a pack cover that covers the battery module and is arranged to contact an upper end surface of the battery module, and a heat sink attached to an upper portion of the pack cover.

[0013] The heat sink may be integral with the pack cover.

[0014] The heat sink may be provided so as to be pre-attached to a given external structure.

[0015] The pack cover may have terminal connection portions provided on an inner surface at an upper end thereof for electrically connecting the electrode terminals of the battery modules to each other.

[0016] When the battery modules are covered by the pack cover, the electrode terminals of one battery module and the electrode terminals of another adjacent battery module may be electrically connected to each other by being in contact with the terminal connection parts in the vertical direction.

[0017] Each of the battery modules may include a battery cell and a module case that houses the battery cell, and the electrode terminal may have a rectangular plate shape and be provided protruding from one side of the module case.

[0018] The module case may include a terminal support portion protruding from one side thereof to support a lower portion of the electrode terminal and having a through hole extending vertically therethrough.

[0019] The pack cover may further include a mounting nut on an inner surface at an upper end thereof, and each battery module may be fixed to the pack cover by a mounting bolt that is inserted into the through-hole of the terminal support portion and fastened perpendicularly to the mounting nut.

[0020] At least one of the mounting bolt and the mounting nut may be made of an insulating material.

[0021] The terminal connection portion may include an interbus bar that comes into surface contact with the electrode terminal and has a fastening hole through which a mounting bolt can pass, and a bracket member that supports the interbus bar and is fixed to the inner surface of the pack cover.

[0022] The bracket member may be form-fitted with a mounting nut and attached to an inner surface of the pack cover.

[0023] The multiple battery modules may be arranged in two rows such that the electrode terminals face each other with respect to the center of the pack case.

[0024] According to another aspect of the present invention, there is provided a vehicle including a battery pack as described above. The vehicle may include an electric vehicle (EV) or a hybrid electric vehicle (HEV). Effect of the Invention

[0025] According to one aspect of the present invention, by providing a heat sink outside the pack case, there is no risk of cooling water leaking, the assembly structure inside the pack case can be simplified, and the energy density can be improved.

[0026] According to another aspect of the present invention, the mechanical fixing structure and the electrical connection structure of the battery module inside the pack case are integrated, thereby making it possible to improve the efficiency of the assembly process.

[0027] Other advantages of the present invention can be understood from the following detailed description, and will become more apparent from the embodiments of the present invention. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of assembling a battery pack according to the prior art. [Diagram 2] 1 is a schematic perspective view of a battery pack according to an embodiment of the present invention; [Diagram 3] FIG. 3 is a partially exploded perspective view of the battery pack of FIG. 2. [Figure 4] 1 is a schematic perspective view of a battery module according to an embodiment of the present invention; [Diagram 5] FIG. 3 is a schematic cross-sectional view taken along II' in FIG. 2. [Figure 6] 3 is a schematic cross-sectional view taken along line II-II' of FIG. 2. [Figure 7] 3 is a schematic cross-sectional view taken along line III-III' of FIG. 2. [Figure 8] 2 is a schematic perspective view of a terminal connection and a mounting nut according to an embodiment of the present invention; FIG. [Figure 9] FIG. 9 is a cross-sectional view of FIG. [Figure 10] 4A to 4C are diagrams illustrating a fixing structure and an electrical connection structure of a battery module according to an embodiment of the present invention. [Figure 11] FIG. 8 corresponds to FIG. 7 and is a diagram illustrating another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms and words used in the present specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as being in accordance with the meaning and concept of the technical idea of ​​the present invention, in accordance with the principle that the inventor himself can appropriately define the concept of the term in order to best describe the invention. Therefore, it should be understood that the embodiment described in this specification and the configuration shown in the drawings are merely the most preferred embodiment of the present invention, and do not represent the entire technical idea of ​​the present invention, and therefore there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0030] FIG. 2 is a schematic perspective view of a battery pack according to one embodiment of the present invention, FIG. 3 is a partially exploded perspective view of the battery pack of FIG. 2, and FIG. 4 is a schematic perspective view of a battery module according to one embodiment of the present invention.

[0031] Referring to these drawings, a battery pack 10 according to one embodiment of the present invention includes a plurality of battery modules 100, a pack case 200 that houses the battery modules 100, and a heat sink 300 attached to an upper portion of the pack case 200.

[0032] 2 and 3, the pack case 200 includes a pack tray 210 and a pack cover 220 which are coupled to each other. The pack tray 210 is provided as a wide-area plate-like body to support the lower part of the battery module 100, and the pack cover 220 is provided to be coupled to the pack tray 210 to cover the entire battery module 100.

[0033] In particular, as will be described later, each battery cell 110 is electrically connected and mechanically fixed via a terminal connection portion 221 provided on the inner surface of the upper end of the pack cover 220.

[0034] Among the main components constituting the battery pack 10, the heat sink 300 corresponding to the cooling component will be described first, and then the internal assembly structure of the battery pack 10 will be described.

[0035] The heat sink 300 of this embodiment has a flow path (not shown) inside through which a coolant can circulate. The coolant flowing through the flow path is not particularly limited as long as it is a fluid that flows easily through the flow path and has excellent cooling properties.

[0036] The heat sink 300 is located on the outer surface of the upper end of the pack cover 220. That is, in the battery pack 10 of the present invention, the heat sink 300 is provided outside the pack case 200, so that the electrical elements and the cooling elements are separated. Therefore, there is no risk of cooling water leakage due to external impact, etc. In addition, since the heat sink 300 is removed from the inside of the pack case 200, the assembly structure can be simplified and the energy density can be increased.

[0037] One method of providing the heat sink 300 on the upper end of the pack cover 220 is to manufacture the heat sink 300 separately from the pack cover 220 and then place and secure it on the pack cover 220. In this case, however, due to the difference in surface roughness between the heat sink 300 and the pack cover 220, the thermal contact resistance increases, which may result in reduced cooling efficiency.

[0038] Therefore, in this embodiment, the pack cover 220 and the heat sink 300 are configured as an integral unit. For example, it can be said that the heat sink 300 is incorporated as part of the pack cover 220, thereby minimizing the thermal contact resistance and the thermal conduction path. By absorbing the heat inside the pack case 200 with this type of heat sink-integrated pack cover 220, the cooling performance does not decrease even if the heat sink 300 is located outside the pack case 200.

[0039] In an alternative embodiment, a thermal interface material (hereinafter referred to as "TIM") is placed on the upper outer surface of the pack cover 220, and the heat sink 300 is placed thereon. The TIM fills the gap between the pack cover 220 and the heat sink 300 to reduce thermal contact resistance. The TIM may be a thermal pad or resin with high thermal conductivity.

[0040] As shown in Figures 4 and 5, each of the battery modules 100 housed inside the pack case 200 includes a battery cell 110, a module case 120 for housing the battery cell 110 in an internal space, and electrode terminals 150a, 150b exposed to the outside of the module case 120.

[0041] The battery cell 110 is a pouch-type secondary battery cell that is widely known in the art. The pouch-type secondary battery cell can be stacked in the internal space of the module case 120, which is advantageous for improving the energy density. Of course, the battery cell 110 is not necessarily limited to a pouch-type secondary battery cell. For example, the battery cell 110 may be replaced with a cylindrical secondary battery cell or a rectangular secondary battery cell.

[0042] The module case 120 may include a base plate 121 and a top plate 122 that cover the lower and upper parts of the battery cells 110, respectively, a pair of side plates 123 that are disposed at the outermost parts in the arrangement direction of the battery cells 110, and a front cover 124 and a rear cover 125 that cover the front and rear parts of the battery cells 110, respectively.

[0043] The top plate 122 of the module case 120 may be provided so as to be in surface contact with the inner surface of the pack cover 220. A thermal pad may further be interposed between the top plate 122 and the inner surface of the pack cover 220.

[0044] The front cover 124 and the rear cover 125 are located at the front and rear of the battery cell 110 and prevent components such as an electrode lead or an interconnection board (ICB) of the battery cell 110 from being exposed to the outside. The electrode terminals 150a, 150b include a positive terminal (electrode terminal 150a) and a negative terminal (electrode terminal 150b), are located at the upper outer side of the front cover 124, are rectangular plate-shaped, have a wide surface placed horizontally, and are provided with holes into which bolts can be inserted in the vertical direction.

[0045] The electrode terminals 150a, 150b may be placed and supported on the terminal support 126. Here, the terminal support 126 is a portion protruding from the front cover 124, supports the lower portions of the electrode terminals 150a, 150b, and may be used as a place for fastening bolts of the battery module 100.

[0046] The terminal support part 126 extends along the width direction of the front cover 124, and a through hole into which a bolt can be inserted may be formed vertically at each of the locations where the positive terminal 150a and the negative terminal 150b are placed. Although not shown, the through holes may be formed to vertically coincide with the holes of the electrode terminals 150a and 150b.

[0047] For reference, the front cover 124 and the terminal support portion 126 have been described separately, but they may be manufactured as an integrated unit. In addition, although not shown, through holes may be provided in other locations where the electrode terminals 150a, 150b are not located so that the mounting bolts 201 can be inserted, and the mounting bolts 201 may be fastened to the pack cover 220.

[0048] The pair of side plates 123 may press and support the battery cells 110 at the outer sides of the outermost battery cells 110 in the arrangement direction of the battery cells 110 .

[0049] Next, the mechanical fixing structure and electrical connection structure of each battery module 100 inside the pack case 200 will be described in detail with reference to Figs.

[0050] In the present embodiment, the battery modules 100 may be eight in total, and may be housed in the pack case 200 in two rows of four each. In this case, the first row of battery modules 100 and the second row of battery modules 100 may be positioned such that their electrode terminals 150a, 150b face each other with respect to the center of the pack case 200 (see FIG. 3). Such an arrangement of the battery modules 100 is advantageous in minimizing the electrical connection distance between the battery modules 100. Of course, this arrangement of the battery modules 100 is merely an example, and the total number and arrangement structure of the battery modules 100 may be changed without being limited.

[0051] The eight battery modules 100 may be placed and supported on the bottom surface of the pack tray 210 and fixed by bolting to a terminal connection portion 221 provided on an inner surface of an upper end of the pack cover 220. Furthermore, the electrode terminals 150a, 150b of adjacent battery modules 100 may come into contact with the terminal connection portion 221 and be electrically connected to each other.

[0052] For example, when the upper part of the module case 120 is covered by the pack cover 220, the electrode terminals 150a, 150b of one battery module 100 and the electrode terminals 150a, 150b of another battery module 100 may be in contact with the terminal connection portion 221 in the vertical direction and electrically connected to each other.

[0053] 8 and 9, the pack cover 220 may further include a mounting nut 225 on an inner surface of its upper end. The mounting nut 225 may be pre-attached to the pack cover 220 by welding. The terminal connection portion 221 may be attached to the pack cover 220 by being form-fitted with the mounting nut 225.

[0054] The terminal connection portion 221 may include an inter-bus bar 221b in the form of a metal bar having a fastening hole 221c through which the mounting bolt 201 can pass and making face-to-face contact with the electrode terminals 150a, 150b of the battery module 100, and a bracket member 221a made of an insulating material that supports the inter-bus bar 221b and is fixed to the inner surface of the upper end of the pack cover 220.

[0055] The bracket member 221a is provided so that its rear surface matches the shape of the mounting nut 225. In addition, the front surface of the bracket member 221a is provided so that the inter-bus bar 221b can be detachably attached thereto so that the fastening holes 221c of the inter-bus bar 221b match the mounting nut 225 vertically.

[0056] The bracket member 221a can be easily attached to the pack cover 220 by attaching double-sided tape 221d to the rear surface thereof. Of course, the bracket member 221a may be attached in other ways, such as by using a combination of bolts and nuts.

[0057] 10, each battery module 100 can be fixed to the pack cover 220 by passing the mounting bolt 201 from the through hole of the terminal support part 126 through the holes of the electrode terminals 150a and 150b and the fastening hole 221c of the inter-bus bar 221b and fastening it to the mounting nut 225. At this time, the positive terminal 150a and the negative terminal 150b of the two adjacent battery modules 100 are in contact with the inter-bus bar 221b of the terminal connection part 221, respectively, so that they can be electrically connected to each other.

[0058] At least one of the mounting bolts 201 and the mounting nuts 225 may be insulating bolts or insulating nuts. By using insulating bolts or insulating nuts, even if the battery module 100 is mechanically fixed to and electrically connected to the pack cover 220 at the same time, a short circuit can be prevented.

[0059] As described above, the battery pack 10 of the present invention has a very easy assembly process since the mechanical fixing structure and the electrical connection structure of the battery modules 100 are integrated. Also, by fixing each battery module 100 to the pack cover 220 instead of fixing it to the pack tray 210 with bolts, the space utilization rate or flexibility of the pack tray 210 can be improved.

[0060] An example of assembling the battery pack 10 of the present invention will now be described briefly.

[0061] The battery pack 10 of the present invention is assembled differently from a general battery pack 10 in that the pack cover 220 is turned upside down, and then the battery module 100 is placed therein and fixed.

[0062] That is, the pack cover 220 is turned upside down, and each battery module 100 is positioned so that the electrode terminals 150a, 150b of the battery module 100 face the cooling pipe and the terminal connection portion 221 of the pack cover 220, respectively.

[0063] Then, the mounting bolts 201 can be fastened to the fastening portions between each battery module 100 and the pack cover 220. That is, by placing each battery module 100 in a predetermined position and fastening the mounting bolts 201, the mechanical fixing work of the battery modules 100 and the series and / or parallel connection work can be easily achieved simultaneously.

[0064] Thereafter, the uneven portion of the pack cover 220 is fitted onto the peripheral portion of the pack tray 210 via the O-ring 230, and the main assembly process is completed.

[0065] Hereinafter, a battery pack 10 according to another embodiment of the present invention will be briefly described with reference to FIG.

[0066] The battery pack 10 according to this embodiment has the same basic mechanical and electrical assembly structure as the battery pack 10 according to the above-described embodiment, but has a different cooling structure.

[0067] That is, in the above-described embodiment, the pack cover 220 and the heat sink 300 are integrated, but in this embodiment, the pack cover 220 and the heat sink 300 are provided as separate units.

[0068] The heat sink 300 may be provided so as to be attached to a predetermined external structure in advance. For example, an upper portion of the heat sink 300 is provided in a form that can be attached to the body 20 of the automobile, and a lower portion of the heat sink 300 is provided so as to face the upper surface of the pack cover 220. Then, after the heat sink 300 is first attached to the body 20 of the automobile, the pack case 200 housing the battery module 100 is attached below the heat sink 300. At this time, a TIM 400 may be further provided on the upper surface of the pack cover 220.

[0069] According to the present embodiment, the structure of each component can be further simplified since the electric energy components and the cooling components constituting the battery pack 10 are completely separated. In particular, since the heat sink 300 can be attached to the vehicle in advance, the work of connecting the cooling water piping required for the cooling structure and ensuring sealing performance can be easily performed.

[0070] Meanwhile, the battery pack according to the present invention may further include various devices for controlling charging and discharging of the battery module, such as a battery management system (BMS), a current sensor, a fuse, etc. The battery pack may be applied to automobiles such as electric vehicles and hybrid vehicles. Of course, the battery pack may also be applied to power storage devices or other IT products.

[0071] Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific preferred embodiments described above. Those skilled in the art can make various modifications without departing from the gist of the present invention as claimed in the claims, and it goes without saying that such modifications are within the scope of the claims.

[0072] Meanwhile, in this specification, terms indicating directions such as up, down, left, right, etc. are used, but such terms are used merely for convenience of explanation, and it will be obvious to those skilled in the art that such terms may change depending on the position of the observer, the position of the object, etc. [Explanation of symbols]

[0073] 100 Battery Module 200 pack case 210 Pack Tray 220 Pack Cover 300 Heatsink

Claims

1. A battery pack including a plurality of battery modules and a pack case in which the battery modules can be installed, the pack case includes a pack tray that supports a lower portion of the battery module, and a pack cover that is provided to cover the battery module, The battery pack further includes a heat sink located on an upper outer surface of the pack cover, the heat sink having a refrigerant therein; the electrode terminals of the battery module are provided to face the inner surface of the upper end of the pack cover; The battery pack, wherein the battery module includes a battery cell and a module case that houses the battery cell, the module case being arranged to contact an inner surface of an upper end of the pack cover.

2. The battery pack according to claim 1 , wherein the heat sink is integral with the pack cover.

3. The battery pack according to claim 1 , wherein the heat sink is attached to an external structure.

4. The battery pack according to claim 1 , wherein the pack cover has a terminal connection portion provided on an inner surface at an upper end thereof for electrically connecting electrode terminals of the battery modules to each other.

5. The battery module includes:

5. The battery pack according to claim 4, wherein, when an upper portion is covered by the pack cover, an electrode terminal of one of the battery modules and an electrode terminal of an adjacent one of the battery modules are in contact with and electrically connected to the terminal connection portion in a vertical direction, respectively.

6. A battery pack as described in claim 4, wherein the electrode terminal is a square plate-shaped terminal protruding from one side of the module case.

7. The battery pack of claim 6, wherein the module case includes a terminal support portion protruding from one side surface to support a lower portion of the electrode terminal and having a through hole extending vertically therethrough.

8. The pack cover further includes a mounting nut on an inner surface of an upper end thereof. The battery pack according to claim 7 , wherein each of the battery modules is fixed to the pack cover by a mounting bolt that is inserted into a through-hole of the terminal support portion and fastened perpendicularly to the mounting nut.

9. 9. The battery pack according to claim 8, wherein at least one of the mounting bolt and the mounting nut is made of an insulating material.

10. The terminal connection portion is an inter-bus bar that is in surface contact with the electrode terminal and has a fastening hole through which the mounting bolt can pass; a bracket member supporting the interbus bar and fixed to an inner surface of the pack cover; 9. The battery pack of claim 8, comprising:

11. The battery pack of claim 10 , wherein the bracket member is form-fitted with the mounting nut and attached to an inner surface of the pack cover.

12. A battery pack comprising a plurality of battery modules and a pack case in which the battery modules can be installed, the pack case includes a pack tray that supports a lower portion of the battery module, and a pack cover that is provided to cover the battery module, The battery pack further includes a heat sink located on an upper outer surface of the pack cover, the heat sink having a refrigerant therein; The battery module includes a battery cell and a module case that houses the battery cell, an electrode terminal of the battery module is provided to protrude from one side surface of the module case and face an inner surface of an upper end of the pack cover; The battery pack, wherein the plurality of battery modules are arranged in two rows, and electrode terminals of the battery modules in different rows are arranged to face each other with respect to a center of the pack case.

13. The battery pack according to claim 1 , wherein the heat sink has an internal flow path through which the coolant can circulate.

14. A battery pack as described in claim 1, wherein a thermal pad is disposed between the module case and the inner surface of the upper end of the pack cover.

15. 2. The battery pack according to claim 1, wherein a thermal pad or a thermally conductive resin is provided on an upper outer surface of the pack cover, and the heat sink is disposed on the thermal pad or the thermally conductive resin.

16. A motor vehicle comprising a battery pack according to any one of claims 1 to 15.

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