Battery pack

Abstract

The present invention relates to a battery pack comprising: a battery pack case accommodating a cell stack assembly, the cell stack assembly comprising a plurality of cells, the battery pack case comprising: a bottom plate for supporting the bottom of the cell stack assembly; a side wall coupled to an edge of the base plate to support a side portion of the cell stack assembly; and a partition wall interposed between any one pair of adjacent cell stack assemblies so as to be coupled to the bottom plate, in which the partition wall includes a hollow portion and a truss girder inserted so as to divide the hollow portion therein.

Description

Technical Field

[0001] The present disclosure relates to a battery pack. The battery pack of the present disclosure is characterized in that it has a structure capable of minimizing heat transfer caused by conduction, convection and radiation due to thermal runaway of a battery cell accommodated therein by using a partition wall including a truss beam having a hollow portion inside and inserted to divide the hollow portion.

[0002] This application claims priority to Korean Patent Application No. 10-2023-0015814 filed on February 6, 2023, which is incorporated herein by reference in its entirety. Background Art

[0003] The types of secondary batteries widely used at present 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 (in other words, a unit battery cell) is about 2.5V to 4.5V. Therefore, if a higher output voltage than this is required, a plurality of such battery cells can be connected in series to form a battery pack. In addition, a battery pack can be configured by connecting a plurality of battery cells in parallel according to the required charge and discharge capacity of the battery pack. Therefore, the number of battery cells included in the battery pack can vary according to the required output voltage or charge and discharge capacity.

[0004] When a battery pack is constructed by connecting a plurality of battery cells in series / parallel, a battery module including at least one battery cell is generally first constructed, and the battery pack is constructed by adding other components using such at least one battery module.

[0005] A conventional battery module generally includes at least one cell stack containing battery cells and a housing structure made of a metal material in the form of a box that accommodates such at least one cell stack, in other words, a module frame or the like.

[0006] In addition, in order to solve the problem that the energy density of the entire battery pack is reduced and the weight of the entire battery pack is increased due to the weight or volume of the module frame itself, a cell stack assembly other than the module frame composition that wraps and protects the cell stack is used as a substitute for the conventional battery module.

[0007] Figure 1 A battery pack case included in a conventional battery pack is shown, and Figure 2 is included in Figure 1 A cross-sectional perspective view of one of the partition walls in a battery pack housing.

[0008] Conventional battery packs that house battery modules or cell stack assemblies have Figure 1In other words, the conventional battery pack includes a pack case 10 having a bottom plate 20 corresponding to a bottom and side walls 30 coupled to edges of the bottom plate 20 , and a plurality of partition walls 40 coupled to the bottom plate 20 to partition the inside of the pack case 10 .

[0009] Conventionally, a hollow type partition wall 40 has been used to reduce the weight of the partition wall 40 while preventing heat from being conducted to the other side through the partition wall 40. However, since the above-mentioned hollow type partition wall 40 has weak mechanical strength, it is difficult to protect the normal battery cell stack assembly from the high explosion pressure when thermal runaway occurs in the battery cell stack assembly.

[0010] Therefore, in order to solve the above mechanical strength problem, the following Figure 2 The partition wall 40 shown has the reinforcing rib 50 , but when the thickness of the reinforcing rib 50 is increased to increase the mechanical strength, there is a problem of difficulty in reducing the weight of the partition wall 40 , and a new problem of not being able to prevent heat conduction through the mass of the reinforcing rib 50 arises.

[0011] On the other hand, there is a problem that if the thickness of the reinforcing rib 50 is reduced, it is difficult to achieve the original purpose of achieving desired mechanical strength.

[0012] Generally, heat is transferred in the form of radiation, convection, and conduction, and there is a need to develop a battery pack including the partition wall 40 having excellent mechanical strength while being able to effectively prevent heat from moving inside the battery pack in various forms as described above.

[0013] [Prior art literature]

[0014] Korean Patent Publication No.10-2022-0014027 Summary of the invention

[0015] Technical issues

[0016] Therefore, the present disclosure is invented to solve the above-mentioned problems and aims to provide a battery pack having a structure capable of preventing heat from being transferred to other battery cells in the case where thermal runaway of any one battery cell leads to series thermal runaway.

[0017] The present disclosure is also directed to providing a battery pack having a partition wall capable of withstanding explosion pressure accompanying thermal runaway of a battery cell in the event of thermal runaway of the battery cell.

[0018] The present disclosure is also directed to providing a battery pack that is lightweight.

[0019] Other objects and advantages of the present disclosure will be understood from the following description, which will become more apparent from the embodiments of the present disclosure, and it will be easily understood that the objects and advantages of the present disclosure can be achieved by the means disclosed in the claims of the patent and their combinations.

[0020] Technical Solution

[0021] The present disclosure provides a battery pack, which includes a battery pack housing for accommodating a cell stack assembly, wherein the cell stack assembly includes a plurality of battery cells, wherein the battery pack housing includes: a bottom plate, which supports a lower portion of the cell stack assembly; a side wall, which is connected to an edge of the bottom plate to support a side portion of the cell stack assembly; and a partition wall, which is inserted between a pair of adjacent cell stack assemblies and connected to the bottom plate, wherein the battery pack housing also includes a hollow portion within the partition wall and a truss beam inserted to divide the hollow portion.

[0022] The inner surface of the partition wall may be coated with a metal film.

[0023] The truss beam may include a plurality of bent portions, and the partition wall may be supported by the bent portions.

[0024] The truss beams may be curved along the length of the partition wall.

[0025] The truss beam may be formed to extend along a height direction of the partition wall.

[0026] A metal film may be coated on the surface of the truss beam.

[0027] The truss beams may comprise any of plastic, aluminum and steel.

[0028] The battery pack case may further include a hollow portion located inside the bottom plate and a lower truss beam inserted to divide the hollow portion.

[0029] The lower truss beam may include a plurality of bent portions, and the bottom plate may be supported by the bent portions.

[0030] The lower truss beam can be bent in the horizontal direction.

[0031] A highly reflective metal film may be coated on the surface of the lower truss beam.

[0032] The lower truss beam may comprise any of plastic and steel.

[0033] Beneficial Effects

[0034] According to the battery pack of the present disclosure, the risk of explosion can be reduced by minimizing internal heat transfer.

[0035] In addition, according to the battery pack of the present disclosure, the energy density can be improved due to its light weight.

[0036] Furthermore, according to the battery pack of the present disclosure, the mechanical strength of the internal frame may be increased to improve stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a perspective view of a battery pack case included in a conventional battery pack.

[0038] Figure 2 is included in Figure 1 A cross-sectional perspective view of any one partition wall in a battery pack housing.

[0039] Figure 3 is a perspective view of a battery pack case included in a battery pack according to a first embodiment of the present disclosure.

[0040] Figure 4 is included in Figure 3 A perspective view of at least one partition wall in a battery pack housing.

[0041] Figure 5 yes Figure 4 Horizontal cross-section of a partition wall.

[0042] Figure 6 yes Figure 5 Floor plan of the dividing wall.

[0043] Figure 7 The dividing wall is shown without the truss beams.

[0044] Figure 8 The process of inserting a truss beam into a partition wall is shown.

[0045] Fig. 9 The direction of force distribution in the truss beam is shown.

[0046] Fig.10 This is an enlarged view of a truss beam portion.

[0047] Fig.11 The cell stack assembly and the partition walls are shown arranged adjacent to each other in a battery housing.

[0048] Fig.12 is a plan view of a partition wall and a cut partition wall of a battery pack according to a second embodiment of the present disclosure.

[0049] Fig.13 is a plan view of a partition wall and a cut partition wall of a battery pack according to a third embodiment of the present disclosure.

[0050] Fig.14is a plan view of a partition wall and a cut partition wall of a battery pack according to a fourth embodiment of the present disclosure.

[0051] Fig.15 is a partial cross-sectional view of a pack case included in a battery pack and a bottom plate included in the pack case according to a fifth embodiment of the present disclosure. DETAILED DESCRIPTION

[0052] The present disclosure will now be described in detail with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. It should be understood that the terms and words used in the specification and claims should not be interpreted in their ordinary or dictionary meanings, but rather, based on the principle that the inventor can define the concept of the term as he or she deems appropriate to best describe the present disclosure, with the meaning and concept consistent with the technical concept of the present disclosure.

[0053] However, it should be understood that the present disclosure is not limited to the specific embodiments, and includes all modifications, equivalents, or substitutes within the spirit and technical scope of the present disclosure.

[0054] Furthermore, in describing the present disclosure, when a detailed description of the configuration or function of the related disclosure is considered to obscure the subject matter of the present disclosure, the detailed description is omitted.

[0055] The present disclosure is shown in the embodiments to explain the present disclosure more comprehensively to those skilled in the art, and therefore, for the sake of clarity, the shapes and sizes of the components in the drawings may be exaggerated, omitted or schematically shown. Therefore, the size or ratio of each component does not necessarily indicate its actual size or ratio.

[0056] The present disclosure relates to a battery pack. The battery pack of the present disclosure is characterized in that it has a structure capable of minimizing heat transfer by conduction, convection, and radiation due to thermal runaway of battery cells accommodated therein by using a partition wall including an inner hollow portion and a truss beam inserted to divide the hollow portion.

[0057] Figures 3 to 11 Respectively relate to a battery pack according to a first embodiment of the present disclosure, and Figures 12 to 15 Respectively relate to battery packs according to second to fifth embodiments of the present disclosure.

[0058] Hereinafter, a battery pack of the present disclosure will be described with reference to the various drawings.

[0059] (First Embodiment)

[0060] Figure 3 is a perspective view of a battery pack case 100 included in a battery pack according to a first embodiment of the present disclosure.

[0061] The battery pack of the present disclosure includes a battery pack case 100 accommodating a battery cell stack assembly A including a plurality of battery cells.

[0062] The cell stack assembly A accommodated in the battery pack of the present disclosure includes a plurality of cells stacked in a first direction and electrically connected to each cell stack assembly A to transfer electric energy from each cell stack assembly A to the outside.

[0063] Each battery cell has a pair of electrode leads with different polarities extending from one or both sides thereof.

[0064] The cell stack assembly A includes a bus bar frame having a bus bar electrically connected to each electrode lead of a plurality of stacked cells, and an end plate coupled to cover the bus bar frame.

[0065] In addition, a module frame may be included that surrounds and covers the periphery of the battery cell stack to protect the plurality of battery cells when necessary.

[0066] like Figure 3 As shown, the battery pack housing 100 includes a bottom plate 110 , a side wall 120 , and a partition wall 130 .

[0067] The bottom plate 110 is used to support the lower part of the battery cell stack assembly A.

[0068] The sidewalls 120 are coupled to edges of the bottom plate 110 to support sides of each battery cell stack assembly A placed on the bottom plate 110 .

[0069] The partition wall 130 is interposed between any pair of adjacently disposed cell stack assemblies A and is coupled to the bottom plate 110. Therefore, the partition wall 130 is used to separate each cell stack assembly A, and also serves as protection to withstand the explosive pressure of the cell stack assembly A accompanying thermal runaway in the event that any one of the cell stack assemblies A expands due to thermal runaway.

[0070] The partition wall 130 of the present disclosure is characterized in that a hollow portion 131 is included therein to achieve light weight, and mechanical strength that may be weakened by the hollow portion 131 is supplemented by a truss beam 140 inserted therein.

[0071] Figure 4 is included in Figure 3 A perspective view of any one of the partition walls 130 in the battery pack housing 100, Figure 5 yes Figure 4 A horizontal cross-sectional view of the partition wall 130, Figure 6 yes Figure 5 A plan view of the partition wall 130, and Figure 7 This is a diagram of the partition wall 130 without the truss beam 140 .

[0072] The partition wall 130 is hollow inside to form a Figure 7 The hollow portion 131 is shown.

[0073] The interior of the hollow portion 131 is in vacuum or filled with air, and is characterized in that heat transfer by conduction, convection, and the like is minimized.

[0074] Although not shown, the partition wall 130 of the present disclosure is also characterized by adding a metal film component to limit heat transfer in the form of radiation through the inner hollow portion 131 .

[0075] In other words, the inner surface of the partition wall 130 may be coated with a metal thin film having high reflectivity to radiant heat.

[0076] The metal film is used to prevent heat from being transferred in the form of radiation through the hollow portion 131 of the partition wall 130. In this case, the metal film may be, for example, aluminum foil, silver foil, and the like.

[0077] In the partition wall 130, a truss beam 140 is included, which is inserted to divide the hollow portion 131, such as Figure 5 and Figure 6 shown.

[0078] The truss beam 140 includes a plurality of bent portions 141 , and serves to support the partition wall 130 using the bent portions 141 .

[0079] like Figure 6 As shown, the truss beam 140 included in the partition wall 130 of the battery pack according to the first embodiment of the present disclosure is extended through a plurality of bent portions 141 to form an equilateral triangle or a regular triangle.

[0080] In other words, the truss beam 140 is characterized in that it has a Warren truss structure. Specifically, the truss beam 140 is formed by a bent portion 141 and an extension of two supporting portions 142 extending in opposite directions from the bent portion 141. In this case, each supporting portion 142 is diagonal and connects one side of the partition wall 130 of the hollow portion 131 to the other side.

[0081] The truss beam 140 extends along the length direction of the partition wall 130. Figure 6 As shown, a plurality of bent portions 141 are formed and extend along the height direction of the partition wall 130. Figure 5 As shown, keep Figure 6 sectional shape to fill all hollow portions 131 inside the partition wall 130 .

[0082] Figure 8 A process of inserting the truss beam 140 widely formed in the length direction and the height direction of the partition wall 130 into the partition wall 130 is shown.

[0083] Thus, the truss beam 140 may be inserted to fill all of the hollow portions 131 (eg, Figure 8 ), to support the partition wall 130 from the inside.

[0084] Fig. 9 The force distribution process of the truss beam 140 in the partition wall 130 when the external force F is applied is shown.

[0085] In addition, according to Fig. 9 , the external force F transmitted from one side is first distributed and transmitted to each curved portion 141 of the truss beam 140, and from one curved portion 141, the force is again distributed in two directions and transmitted to the opposite curved portion 141. In addition, the external force F passing through the truss beam 140 inside the partition wall 130 can be temporarily dispersed and weakened, and thus only half of the force is transmitted to the opposite side of the partition wall 130.

[0086] The above-mentioned features of the truss beam 140 can also be applied to heat transfer, in other words, the high temperature heat transferred with the external force F can be dispersed through the truss beam 140 and weakened as it moves. In addition, the heat moving through the truss beam 140 can be partially cooled by the air in the hollow portion 131, etc.

[0087] Although not shown, the surface of the truss beam 140 may be coated with a highly reflective metal film, and the inner surface of the partition wall 130 may also be coated with a highly reflective metal film. In other words, the heat radiated into the hollow portion 131 may be reflected by the surface of the truss beam 140 (the truss beam 140 divides the space inside the hollow portion 131) and may not move to the other side.

[0088] The truss beam 140 may be made of any one of reinforced plastic, aluminum, and steel. However, it is preferred that the truss beam 140 is made of the same material as the partition wall 130 (which is made of metal). This is because coupling via welding between the same materials is the best way to fix the truss beam 140 to the inside of the partition wall 130. In this case, welding is performed between the bent portion 141 of the truss beam 140 and the inner surface of the partition wall 130 that contacts the bent portion 141.

[0089] Fig.10 It is an enlarged view of a portion of the truss beam 140 .

[0090] like Fig.10 As shown, it can be seen that the outer end of the bent portion 141 is formed to be planar so as to be engaged with the inner surface of the partition wall 130 .

[0091] Fig.11A pair of cell stack assemblies A are shown disposed adjacent to each other in a battery pack housing 100 and a partition wall 130 interposed therebetween. (For ease of understanding, the top of the partition wall 130 is shown as being cut away.)

[0092] The partition wall 130 supports two battery cell stack assemblies A in close contact with each other on both sides of the partition wall 130, such as Fig.11 In the event that any of the cell stack assemblies A undergoes thermal runaway, expands, and releases high-temperature heat and gas, the truss beams 140 and the hollow portion 131 within the partition wall 130 prevent or reduce the generated explosion pressure and heat transfer to the cell stack assembly A on the opposite side.

[0093] The battery pack of the present disclosure may further include an upper case (not shown) coupled to the pack case 100 to cover an upper portion of the cell stack assembly A accommodated in the pack case 100 .

[0094] The upper portion of the housing is not an essential feature of the present disclosure and will not be described further.

[0095] (Second Embodiment)

[0096] Fig.12 1 is a plan view of a partition wall 130 of a battery pack according to a second embodiment of the present disclosure and a cut partition wall 130 .

[0097] The truss beam 140 includes Fig.12 A plurality of bent portions 141 are shown, and are used to support the partition wall 130 using the bent portions 141 .

[0098] The truss beam 140 is formed as an extension of a bent portion 141 and two supporting portions 142 oppositely extending from the bent portion 141. In this case, each supporting portion 142 has alternating vertical lines and diagonal lines, and connects one side of the partition wall 130 of the hollow portion 131 to the other side.

[0099] Specifically, any one of the support portions 142 extending from the bent portion 141 vertically connects one side and the other side of the partition wall 130 , and the other support portion 142 diagonally connects one side and the other side of the partition wall 130 .

[0100] By changing the length of the support portion 142 included in the truss beam 140 in this manner, it is possible to aim to transfer force and heat direction unevenly.

[0101] (Third Embodiment)

[0102] Fig.13 1 is a plan view of a partition wall 130 of a battery pack according to a third embodiment of the present disclosure and a cut partition wall 130 .

[0103] The truss beam 140 includes Fig.13 A plurality of bent portions 141 are shown, and are used to support the partition wall 130 using the bent portions 141 .

[0104] The truss beam 140 is formed as an extension of a bent portion 141 and two supporting portions 142 extending in opposite directions from the bent portion 141. In this case, each supporting portion 142 has alternating vertical lines and diagonal lines and connects one side of the partition wall 130 of the hollow portion 131 to the other side.

[0105] Specifically, any one of the support portions 142 extending from the bent portion 141 vertically connects one side and the other side of the partition wall 130 , and the other support portion 142 diagonally connects one side and the other side of the partition wall 130 .

[0106] By changing the length of the support portion 142 included in the truss beam 140 in this manner, it is possible to aim to transfer force and heat direction unevenly.

[0107] (Fourth Embodiment)

[0108] Fig.14 2 is a plan view of a partition wall 130 of a battery pack according to a fourth embodiment of the present disclosure and a cut partition wall 130 .

[0109] The truss beam 140 includes Fig.14 A plurality of bent portions 141 are shown, and are used to support the partition wall 130 using the bent portions 141 .

[0110] The truss beam 140 is formed as an extension of a bent portion 141 and two supporting portions 142 extending in opposite directions from the bent portion 141. In this case, one bent portion 141 is connected to a pair of supporting portions 142 extending diagonally, and the supporting portions 142 connected to the other bent portion 141 are alternately vertical and diagonal, thereby connecting one side of the partition wall 130 of the hollow portion 131 with the other side.

[0111] The truss beam 140 of this structure is intended to distribute force and pressure toward both ends centered on a bent portion 141 connected to two diagonally shaped support portions 142 .

[0112] (Fifth Embodiment)

[0113] Fig.15 is a partial cross-sectional view of a pack case included in a battery pack according to a fifth embodiment of the present disclosure and a bottom plate included in the pack case.

[0114] In the same manner as the partition wall 130 , the bottom plate 110 has a hollow structure, in other words, includes a lower hollow portion therein, and the battery pack case 100 of the present disclosure further includes a lower truss beam 150 inserted to partition the lower hollow portion of the bottom plate 110 .

[0115] Reference Fig.15 The lower truss beam 150 includes a plurality of bent portions 141 , and supports the bottom plate 110 using the bent portions 141 .

[0116] The lower truss girder 150 is disposed inside the lower hollow portion of the bottom plate 110 in a configuration in which the truss girder 140 applied to the partition wall 130 is inverted, in other words, the lower truss girder 150 is bent in a horizontal direction.

[0117] The inner surface of the bottom plate 110 may be coated with a highly reflective metal film, and the metal film may also be coated on the surface of the lower truss beam 150 .

[0118] The lower truss beam 150 may include any one of plastic and steel. Preferably, the lower truss beam 150 is the same material as the bottom plate 110 to facilitate joining and the like.

[0119] like Fig.15 As shown, the lower truss beam 150 supports the weight of the battery cell stack assembly A located on the upper portion of the bottom plate 110. In particular, when one of the battery cell stack assemblies A expands or explodes due to thermal runaway, the explosion pressure can be distributed. In addition, it absorbs and cools the high temperature heat generated by the thermal runaway.

[0120] As described above, the present invention has been described in more detail through the drawings and embodiments. However, since the configuration described in the drawings or embodiments described herein is only an embodiment of the present invention and does not represent the entire technical spirit of the present invention, it should be understood that the present invention covers various equivalents, modifications and substitutions when submitting this application.

[0121] [Explanation of Reference Numbers]

[0122] 10: (Conventional technology) battery pack housing

[0123] 20: (Conventional technology) bottom plate

[0124] 30: (Conventional technology) side wall

[0125] 40: (Conventional Technology) Partition Wall

[0126] 50: (Conventional technology) Strengthening ribs

[0127] 100: Battery pack housing

[0128] 110: Base plate

[0129] 120: Sidewall

[0130] 130: Partition wall

[0131] 131: Hollow part

[0132] 140: Truss beam

[0133] 141: Bending part

[0134] 142: Support

[0135] 150: Lower truss beam

[0136] A: Battery stack assembly

[0137] F: External force

Claims

1. A battery pack, comprising a battery pack housing for accommodating a battery cell stack assembly, wherein the battery cell stack assembly comprises a plurality of battery cells, in, The battery pack housing comprises: A bottom plate, the bottom plate supporting the lower portion of the battery cell stack assembly; a side wall coupled to an edge of the bottom plate to support a side of the battery cell stack assembly; and a partition wall interposed between any pair of adjacent battery cell stack assemblies and coupled to the bottom plate, The battery pack housing further includes a hollow portion within the partition wall and a truss beam inserted to divide the hollow portion.

2. The battery pack according to claim 1, wherein: The inner surface of the partition wall is coated with a metal film.

3. The battery pack according to claim 1, wherein: The truss beam includes a plurality of bent portions, and the partition wall is supported by the bent portions.

4. The battery pack according to claim 1, wherein: The truss beam is bent along the length direction of the partition wall.

5. The battery pack according to claim 1, wherein: The truss beam is formed to extend in a height direction of the partition wall.

6. The battery pack according to claim 1, wherein: A metal film is coated on the surface of the truss beam.

7. The battery pack according to claim 1, wherein: The truss beam includes any one of plastic, aluminum and steel.

8. The battery pack according to claim 1, wherein: The battery pack case further includes a hollow portion inside the bottom plate and a lower truss beam inserted to divide the hollow portion.

9. The battery pack according to claim 8, wherein: The lower truss beam includes a plurality of bent portions, and supports the bottom plate using the bent portions.

10. The battery pack according to claim 8, wherein: The lower truss beam is bent in a horizontal direction.

11. The battery pack according to claim 8, wherein: A highly reflective metal film is coated on the surface of the lower truss beam.

12. The battery pack according to claim 8, wherein: The lower truss beam comprises any one of plastic and steel.

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