Battery pack

Abstract

A battery pack is disclosed. The battery pack comprises a plurality of battery cells, each of the battery cells comprises a terminal part, and the terminal part comprises a first terminal and a second terminal; a side surface frame to which the plurality of battery cells are inserted in an insertion direction; a plurality of connection parts, each of which is fixed at a position between adjacent battery cells in the insertion direction among the plurality of battery cells; and a plurality of bus bars connected to the plurality of connection portions, each of the plurality of bus bars being electrically connected to a terminal portion of an adjacent battery cell.

Description

Technical Field

[0001] The present disclosure relates to a battery pack that does not require a holder for mounting a bus bar, does not cause deformation due to welding heat, and has improved durability. Background Art

[0002] Secondary batteries are also receiving attention as a main power source for electric vehicles, hybrid vehicles, plug-in hybrid vehicles, etc. Such vehicles are proposed as a substitute for conventional gasoline and diesel vehicles to solve various problems such as air pollution.

[0003] In electric vehicles and the like, a battery module is used in which a plurality of battery cells are stacked, and the battery cells are electrically connected in series and in parallel to provide a high-output and large-capacity battery.

[0004] In the battery module, terminals exposed at both ends of each battery cell are electrically connected by a bus bar to provide a high voltage in a case where a plurality of battery cells are inserted into the side surface frame.

[0005] In the battery module, a bus bar holder connected to a plurality of bus bars is installed to electrically connect a plurality of battery cells.

[0006] Since the bus bar holder is welded to the upper portion of the side surface frame, there is a problem in that durability is deteriorated due to deformation caused by welding heat during a bonding process. Summary of the invention

[0007] An embodiment of the present disclosure is to provide a battery pack that does not require a bus bar holder for electrical connection of a plurality of battery cells, does not generate deformation caused by welding heat, and improves durability.

[0008] A battery pack according to an embodiment of the present disclosure includes: a plurality of battery cells, each of the battery cells including a terminal portion, the terminal portion including a first terminal and a second terminal; a side surface frame, the plurality of battery cells are inserted into the side surface frame in an insertion direction; a plurality of connecting portions, each of the plurality of connecting portions being fixed at a position between adjacent battery cells along the insertion direction among the plurality of battery cells; and a plurality of bus bars connected to the plurality of connecting portions, each of the plurality of bus bars being electrically connected to the terminal portions of adjacent battery cells.

[0009] Each of the plurality of connection portions may include: a first connection portion fixed to a position between adjacent battery cells; a second connection portion fixed to a position between adjacent battery cells and connected to one of the plurality of bus bars at a position spaced apart from the first connection portion; and a buffer connection portion connecting the first connection portion and the second connection portion to each other with a variable length in a direction perpendicular to the insertion direction.

[0010] The first connection portion, the second connection portion, and the buffer connection portion may be connected in a direction perpendicular to the insertion direction.

[0011] The first connection portion may include: a first frame fixed at a position between adjacent battery cells; and a second frame coupled to a portion of an upper surface of the first frame and protruding from the upper surface of the first frame.

[0012] A first insertion protrusion inserted between adjacent battery cells may protrude from a lower portion of the first frame.

[0013] The second frame may be formed to have a length shorter than that of the first frame.

[0014] A supporting protrusion fixed to an upper surface of the first frame protrudes from a lower portion of the second frame.

[0015] The supporting protrusion may be fixed to the first frame by heat fusion.

[0016] The second connection portion may include a third frame disposed at a position between the adjacent battery cells at a position spaced apart from the first connection portion, and one of the bus bars is fixed to the third frame.

[0017] A second insertion protrusion interposed between adjacent battery cells may protrude from a lower portion of the third frame.

[0018] One of the bus bars may be fixed to the third frame by heat fusion.

[0019] A first end of the buffer connection portion may be connected to a side surface of the first frame, a second end of the buffer connection portion may be connected to a side surface of the third frame, and a bend portion may be formed between the first and second ends of the buffer connection portion, the bend portion having a variable length in a direction perpendicular to the insertion direction.

[0020] The bent portion may be bent upward below the adjacent battery cells.

[0021] Each of the bus bars may include: a first portion protruding from a first side of the third frame to be electrically connected to a terminal portion of a first battery cell among adjacent battery cells; and a second portion protruding from a second side of the third frame to be electrically connected to a terminal portion of a second battery cell among adjacent battery cells and formed to have a size different from that of the first portion.

[0022] The temperature sensor fixing portion may protrude from one side of one of the plurality of connecting portions.

[0023] The temperature sensor fixing part may include a sensor protrusion protruding from a side surface of the second frame of one connection part among the plurality of connection parts, and a sensor hole for mounting the temperature sensor is formed in the sensor protrusion.

[0024] The temperature sensor may be mounted in the sensor hole of the sensor protrusion and may be connected to a cable connected to the protection circuit module, the cable being connected to the protection circuit module.

[0025] An insulating sheet (eg, a mica sheet) may be attached to each of the plurality of battery cells.

[0026] According to an embodiment of the present disclosure, a bus bar can be electrically connected to a plurality of battery cells at an upper portion of a battery cell without using a conventional bus bar holder for mounting the bus bar. Therefore, there is no need to change the structure (such as bending a portion of a side frame constituting a side surface frame to connect a conventional holder), thereby being able to optimize the mounting configuration and reduce manufacturing costs.

[0027] According to an embodiment of the present disclosure, since the bus bar is fixed to the upper portion of the battery cell without using a conventional bus bar holder, the installation height of the battery pack may be reduced to optimize the installation configuration of the battery pack.

[0028] According to an embodiment of the present disclosure, a connection portion can be fixed to an upper portion of a battery cell without using welding, so that durability can be improved by preventing occurrence of deformation due to welding heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a perspective view schematically showing a battery pack according to a first embodiment of the present disclosure.

[0030] Figure 2 It is schematically shown Figure 1 A plan view of a state in which a pair of battery cells of a battery pack are electrically connected via a connecting portion and a bus bar.

[0031] Figure 3 It is along Figure 2 A cross-sectional view cut along line AA.

[0032] Figure 4 is a perspective view schematically showing a state in which the bus bar according to the first embodiment of the present disclosure is fixed to a connection portion.

[0033] Figure 5 is a schematic diagram showing the busbars fixed to Figure 4 A plan view of the state of the connection part.

[0034] Figure 6 is a schematic diagram showing the busbars fixed to Figure 4A side view of the state of the connecting portion.

[0035] Figure 7 It is along Figure 6 Cross-sectional view of the line BB cut.

[0036] Figure 8 1 is a main portion plan view schematically showing a state in which a temperature sensor mounted at a temperature sensor fixing portion according to the first embodiment of the present disclosure is connected to a cable.

[0037] Fig. 9 : is a main part perspective view schematically showing a state in which a temperature sensor fixing portion is formed at a connecting portion according to the first embodiment of the present disclosure.

[0038] Fig.10 yes Fig. 9 Side view of.

[0039] Fig.11 1 is a main part exploded perspective view schematically showing a state in which a connection portion formed with a temperature sensor fixing portion is separated from a battery cell according to the first embodiment of the present disclosure.

[0040] Fig.12 is a side view schematically showing a connecting portion of the second embodiment of the present disclosure. DETAILED DESCRIPTION

[0041] Embodiments of the present disclosure will be described more fully below with reference to the accompanying drawings so that those skilled in the art can easily implement the embodiments. The present disclosure may be modified in various ways without departing from the spirit or scope of the present disclosure. In order to clearly describe the present disclosure, parts or portions not related to the description are omitted in the accompanying drawings, and the same or similar components are represented by the same reference numerals throughout the specification.

[0042] Figure 1 is a perspective view schematically showing a battery pack according to a first embodiment of the present disclosure, Figure 2 It is schematically shown Figure 1 A plan view of a state in which a pair of battery cells of a battery pack are electrically connected through a connecting portion and a bus bar, and Figure 3 It is along Figure 2 A cross-sectional view cut along line AA.

[0043] like Figures 1 to 3As shown in , a battery pack 100 according to a first embodiment of the present disclosure may include: a plurality of battery cells 10, each battery cell 10 including a terminal portion 11, the terminal portion 11 including a first terminal 11a and a second terminal 11b; a side surface frame 20, a plurality of battery cells 10 are inserted into the side surface frame 20 in a first (insertion) direction (x-axis direction); a plurality of connecting portions 30, fixed at an upper portion of the side surface frame 20 to an upper position between the battery cells 10 along the first direction; and a bus bar 37, connected to the connecting portion 30 and electrically connected to the terminal portions of a pair of adjacent battery cells 10.

[0044] The side surface frame 20 may include: a first side frame 21, supporting one side surface of the plurality of battery cells 10; a second side frame 23, supporting the other side surface of the plurality of battery cells 10; a first end frame 25, having two ends connected to one end of each of the first side frame 21 and the second side frame 23; and a second end frame 27, having two ends connected to the other end of each of the first side frame 21 and the second side frame 23.

[0045] The first side frame 21 may be installed to support one side of the plurality of battery cells 10 .

[0046] The second side frame 23 may be installed to support the other side of the plurality of battery cells 10 .

[0047] The first end frame 25 may be installed to connect one end of the first side frame 21 and one end of the second side frame 23. In some embodiments, one end of the first end frame 25 may be connected to one end of the first side frame 21 by a fastening member, and the other end of the first end frame 25 may be connected to one end of the second side frame 23 by a fastening member.

[0048] The second end frame 27 may be installed to connect the other end of the first side frame 21 and the other end of the second side frame 23. In some embodiments, one end of the second end frame 27 may be connected to the other end of the first side frame 21 by a fastening member, and the other end of the second end frame 27 may be connected to the other end of the second side frame 23 by a fastening member.

[0049] The connection portion 30 and the bus bar 37 for electrically connecting the plurality of battery cells 10 to each other may be mounted at an upper portion of the side surface frame 20 .

[0050] The plurality of battery cells 10 may be inserted into the side surface frame 20 along the first direction, and when the plurality of connection parts 30 are provided at upper portions of the plurality of battery cells 10 , the plurality of connection parts 30 may be fixed at upper portions of the plurality of battery cells 10 .

[0051] The connection part 30 may not be directly fixed to the side surface frame 20. The connection part 30 may be fixed to the upper portions of the plurality of battery cells 10 without a separate fastening member.

[0052] Figure 4 is a perspective view schematically showing a state in which the bus bar of the first embodiment of the present disclosure is fixed to a connecting portion, Figure 5 is a schematic diagram showing the busbars fixed to Figure 4 A plan view of the state of the connection part, Figure 6 is a schematic diagram showing the busbars fixed to Figure 4 A side view of the state of the connection portion, and Figure 7 It is along Figure 6 Cross-sectional view of the line BB cut.

[0053] Reference Figures 4 to 7 , the connection part 30 may include a first connection part 31 fixed at a position between the battery cells 10 and a second connection part 35 fixed to a position between the battery cells 10 and connected to the bus bar 37 at a position spaced apart from the first connection part 31. The connection part may further include a buffer connection part 33 connecting the first connection part 31 and the second connection part 35 to each other with a variable length.

[0054] The first connection portion 31 , the second connection portion 35 , and the buffer connection portion 33 may be connected in a second direction (y-axis direction) perpendicular to the first direction, and may extend in the second direction at positions between the battery cells 10 .

[0055] In a state in which the first connection portion 31 is disposed at an upper portion between the battery cells 10 , a portion of a lower portion of the first connection portion 31 may be interposed between the battery cells 10 .

[0056] The first connection part 31 may include a first frame 311 fixed to a position between the battery cells 10 and having one side connected to one end of the buffer connection part 33 , and a second frame 313 coupled to a portion of an upper surface of the first frame 311 .

[0057] The first frame 311 may have an approximately rectangular parallelepiped shape and may be fixed without using a separate fastening member, etc., in a state where the first frame 311 is installed between the battery cells 10. The first frame 311 is not limited to the rectangular parallelepiped shape, and a portion of the first frame 311 may include a circular shape, a plate shape, etc.

[0058] One side of the first frame 311 may be disposed at an upper edge of the side surface frame 20 , and the other side of the first frame 311 may extend to be connected to one end of the buffer connection part 33 .

[0059] The first insertion protrusion 311a may protrude from a lower portion of the first frame 311. That is, the first insertion protrusion 311a may protrude from a lower surface of the first frame 311. The first insertion protrusion 311a may have a length corresponding to that of the first frame 311.

[0060] The first insertion protrusion 311a protrudes from the lower portion of the first frame 311 to be inserted into the lower portions of a pair of battery cells 10 positioned adjacent to each other. The first frame 311 may be stably disposed at the upper portion of the battery cell 10 by the position fixing action of the first insertion protrusion 311a.

[0061] In some embodiments, without using a conventional fastening member or retainer, the first frame 311 may be fixed at the upper portion of the battery cell 10 in a state of being disposed at the upper portion of the battery cell 10 by a fixing behavior in which the first insertion protrusion 311a protruding from the lower portion of the first frame 311 is inserted into a position between the battery cell 10 and an adjacent battery cell 10. For example, in the present embodiment, the configuration of a conventional retainer is unnecessary, thereby optimizing the mounting configuration.

[0062] The first frame 311 may be connected to the second frame 313 , and one end of the buffer connection part 33 may be connected to one side of the first frame 311 .

[0063] A portion of the second frame 313 along the length direction may be connected to the first frame 311 so that the second frame 313 is connected to the buffer connection portion 33 .

[0064] The second frame 313 may have a length shorter than that of the first frame 311 , and a lower surface of the second frame 313 may be connected to an upper surface of the first frame 311 .

[0065] The second frame 313 may be connected to the upper portion of the first frame 311 such that the second frame 313 protrudes from the first frame 311, and the second frame 313 may be fixed to the upper portion of the first frame 311 by heat fusion. In some embodiments, the second frame 313 may be fixed to the upper surface of the first frame 311 by heat fusion in a state where the lower portion of the second frame 313 contacts the upper surface of the first frame 311 without using a separate fastening member.

[0066] To this end, a support protrusion 313a for fixing the second frame 313 to the first frame 311 in a protruding state protrudes from a lower portion of the second frame 313. The support protrusion 313a can allow the second frame 313 to be disposed at a height corresponding to a height at which the bus bar 37 protrudes from an upper portion of the second connection portion 35. For example, the installation heights of the second frame 313 and the bus bar 37 may be the same or similar so that there is no step difference between the second frame 313 and the bus bar 37. Therefore, by preventing the occurrence of interference of the bus bar 37 with a predetermined component, durability can be improved.

[0067] The first frame 311 may be connected to the second frame 313 in a state where the first frame 311 is connected to the buffer connection portion 33. The buffer connection portion 33 allows a change in the distance or height at which the first frame 311 and the second frame 313 are connected to each other. Even if the distance or height between the battery cells 10 changes when expansion occurs due to an abnormality in the battery cells 10, the buffer connection portion 33 may achieve a stable electrical connection between the battery cells 10. For example, one end of the buffer connection portion 33 may be connected to a side surface of the first frame 311, the other end of the buffer connection portion 33 may be connected to a side surface of the second connection portion 35 (e.g., the third frame 35a of the second connection portion 35), and the connection length between the ends of the buffer connection portion 33 may be variable.

[0068] The buffer connection portion 33 may be formed to have a width smaller than that of the first frame 311 and the second frame 313 , may be made of a material that is the same as or similar to that of the first frame 311 and the second frame 313 , and may be connected to the first frame 311 by welding.

[0069] If expansion occurs due to an abnormality in the battery cell 10 so that the connection state between the first frame 311 and the second connection portion 35 (e.g., the third frame 35a of the second connection portion 35) changes, the bent portion 33a formed at the buffer connection portion 33 may compensate for the changed connection state. The bent portion 33a may be formed at one end and the other end of the buffer connection portion 33, and the bent portion 33a may be bent in a lower direction of the battery cell 10 (e.g., the opposite direction of the z-axis direction) to stably compensate for the changed state of the vertical positions of the first frame 311 and the second connection portion 35 (e.g., the third frame 35a of the second connection portion 35).

[0070] Although the bent portion 33 a is illustratively described as being bent in a single shape at a position between both ends of the buffer connection portion 33 , the present disclosure is not necessarily limited thereto, and the shape of the bent portion 33 a may be changed to a plurality of bent shapes.

[0071] The second connection part 35 may be connected to the other end of the buffer connection part 33 and may be installed to electrically connect the bus bar 37 to the battery cell 10 while being fixed to the upper portion of the battery cell 10 in a state where the second connection part 35 is disposed on the upper portion of the battery cell 10 .

[0072] The second connection portion 35 may include a third frame 35a, the third frame 35a is disposed at a position between the battery cells 10 at a position spaced apart from the first connection portion 31, and the bus bar 37 is fixed to the third frame 35a. The third frame 35a may be installed at a position between the battery cells 10 in a state extending in a second direction perpendicular to the first direction. In a state in which the third frame 35a is disposed at an upper portion between the battery cells 10, a portion of a lower portion of the second connection portion 35 may be interposed between the battery cells 10.

[0073] To this end, the second insertion protrusion 35b may protrude from the lower portion of the third frame 35a. That is, the second insertion protrusion 35b may protrude from the lower surface of the third frame 35a, and the second insertion protrusion 35b may have a length corresponding to the length of the third frame 35a. The second insertion protrusion 35b may protrude from the lower portion of the third frame 35a to be inserted between a pair of battery cells 10 adjacent to each other. The second connection portion 35 may be stably disposed at the upper portion of the battery cell 10 by the position fixing behavior of the second insertion protrusion 35b.

[0074] As described above, the second insertion protrusions 35b may protrude from the lower portion of the third frame 35a to be inserted into the lower portions of a pair of battery cells 10 adjacent to each other. Therefore, the third frame 35a may be stably disposed at the upper portion of the battery cell 10 by the position fixing action of the second insertion protrusions 35b.

[0075] In some embodiments, without using a conventional fastening member or retainer, the second connection portion 35 may be fixed at the upper portion of the battery cell 10 in a state of being disposed at the upper portion of the battery cell 10 by a fixing behavior in which the second insertion protrusion 35b protruding from the lower portion of the third frame 35a is inserted into a position between the battery cells 10. For example, in the present embodiment, the configuration of a conventional retainer may be unnecessary, thereby optimizing the mounting configuration.

[0076] As described above, the connection portion 30 may be fixed without using welding by inserting the first and second insertion protrusions 311a and 35b into positions between the battery cells 10. Therefore, it is possible to improve durability by preventing occurrence of deformation due to welding heat.

[0077] The bus bar 37 may be fixed to the third frame 35a and electrically connected to the terminal portion 11 of the battery cell 10. The bus bar 37 may be fixed to the third frame 35a by heat fusion, and the bus bar 37 may extend to both sides of the third frame 35a to be electrically connected to the terminal portion 11 of the adjacent battery cell 10. The bus bar 37 may include a first portion 37a and a second portion 37b, the first portion 37a protruding from one side of the third frame 35a to be electrically connected to the terminal portion 11 of the first battery cell 10, and the second portion 37b protruding from the other side of the third frame 35a to be electrically connected to the terminal portion 11 of the second battery cell 10 and formed to have a size different from that of the first portion 37a. The first portion 37a may be electrically connected to any one of the first terminal 11a and the second terminal 11b of one battery cell 10 in a pair of adjacent battery cells 10. The second portion 37b may be electrically connected to any one of the first terminal 11a and the second terminal 11b of the other battery cell 10 in a pair of adjacent battery cells 10. The first portion 37 a and the second portion 37 b of the bus bar 37 may be electrically connected to the terminal portion 11 by heat fusion.

[0078] Insulating sheet (e.g., mica sheet) 40 (see Fig. 9 ) may be attached to each side surface of the plurality of battery cells 10. In some embodiments, the insulating sheet 40 may be attached at a position between the battery cells 10 so that the battery cells 10 are stably mounted and insulated from each other in a state where the battery cells 10 are inserted into the side surface frame 20 along the first direction.

[0079] Temperature sensor fixing portion 50 (see Figure 8 ) may protrude from one side of any one of the plurality of connection parts 30. The temperature sensor fixing part 50 may protrude from a side surface of the second frame 313 constituting the connection part 30 to fix the temperature sensor 52.

[0080] Figure 8 is a main part plan view schematically showing a state in which a temperature sensor installed at a temperature sensor fixing portion according to a first embodiment of the present disclosure is connected to a cable, Fig. 9 is a main part perspective view schematically showing a state in which a temperature sensor fixing portion is formed at a connecting portion according to a first embodiment of the present disclosure, Fig.10 yes Fig. 9 A side view of Fig.11 1 is a main part exploded perspective view schematically showing a state in which a connection portion formed with a temperature sensor fixing portion is separated from a battery cell according to the first embodiment of the present disclosure.

[0081] Reference Figures 8 to 11The temperature sensor fixing part 50 may include a sensor protrusion 51 protruding from a side surface of the second frame 313. A sensor hole 53 is formed at a position where the temperature sensor 52 is installed. The sensor protrusion 51 may be formed by bending at a side surface of one end of the second frame 313, and the sensor hole 53 may be formed to penetrate the inside of the sensor protrusion 51.

[0082] The temperature sensor 52 may be connected to a cable 60 connected to the protection circuit module in a state where the temperature sensor 52 is installed in a sensor hole 53 formed at the sensor protrusion 51. One side of the cable 60 may be connected to the temperature sensor 52, and the other side of the cable 60 may be connected to the protection circuit module. The cable 60 is electrically connected to the temperature sensor 52 to transmit a measurement signal of the temperature sensor 52.

[0083] As described above, the battery pack 100 of the present embodiment can electrically connect the bus bar 37 to the plurality of battery cells 10 without using a conventional bus bar holder for mounting the bus bar. Therefore, there is no need to change the structure such as bending a portion of the side frame constituting the side surface frame 20 to connect the conventional bus bar holder, thereby being able to optimize the mounting configuration and reduce the manufacturing cost.

[0084] In some embodiments, since the bus bar 37 is fixed to the upper portion of the battery cell 10 without using a conventional bus bar holder, the installation height of the battery pack 100 may be reduced to optimize the installation configuration of the battery pack 100 .

[0085] Fig.12 2 is a side view schematically showing a connection portion of a second embodiment of the present disclosure. Figures 1 to 11 The same reference numerals in the drawings represent the same or similar components having the same or similar functions. Therefore, detailed descriptions of the same reference numerals are omitted.

[0086] like Fig.12 As shown in FIG. 1 , in the buffer connection part 133 of the battery pack 100 according to the second embodiment of the present disclosure, a plurality of bent parts 133a may connect the first connection part 31 and the second connection part 35. Even if the distance or height between the battery cells 10 changes when swelling occurs due to an abnormality in the battery cells 10, the buffer connection part 133 may achieve a stable electrical connection between the battery cells 10.

[0087] While the disclosure has been described in connection with what are presently considered to be practical embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the purview of the appended claims.

[0088] <Description of the symbol> 10: Battery Cell 11: Terminal 11a: First terminal 11b: Second terminal 20: Side surface frame 21: First side frame 23: Second side frame 25: First end frame 27: Second end frame 30: Connection 31: First connection part 311: First Frame 311a: first insertion protrusion 313: Second Frame 313a: Support protrusion 33, 133: Buffer connection 33a, 133a: curved part 35: Second connection part 35a: Third Frame 35b: Second insertion protrusion 37: Busbar 37a: Part I 37b: Part 2 40: Insulation sheet 50: Temperature sensor fixing part 51: Sensor protrusion 52: Temperature sensor 53: Sensor hole 60: Cable.

Claims

1. A battery pack, comprising: a plurality of battery cells, each of the battery cells comprising a terminal portion, the terminal portion comprising a first terminal and a second terminal; a side surface frame to which the plurality of battery cells are inserted in an insertion direction; a plurality of connection portions, each of the plurality of connection portions being fixed at a position between battery cells adjacent along the insertion direction among the plurality of battery cells; as well as A plurality of bus bars are connected to the plurality of connection portions, each of the plurality of bus bars being electrically connected to the terminal portion of the adjacent battery cells.

2. The battery pack according to claim 1, wherein: Each of the plurality of connecting parts comprises: A first connecting portion, fixed to a position between the adjacent battery cells; a second connection portion fixed to a position between the adjacent battery cells and connected to one of the plurality of bus bars at a position spaced apart from the first connection portion; and A buffer connection portion connects the first connection portion and the second connection portion to each other with a variable length in a direction perpendicular to the insertion direction.

3. The battery pack according to claim 2, wherein: The first connection portion, the second connection portion, and the buffer connection portion are connected in the direction perpendicular to the insertion direction.

4. The battery pack according to claim 3, wherein: The first connecting portion comprises: a first frame fixed at a position between the adjacent battery cells; and The second frame is coupled to a portion of an upper surface of the first frame and protrudes from the upper surface of the first frame.

5. The battery pack according to claim 4, wherein: A first insertion protrusion inserted between the adjacent battery cells protrudes from a lower portion of the first frame.

6. The battery pack according to claim 5, wherein: The second frame is formed to have a length shorter than that of the first frame.

7. The battery pack according to claim 5, wherein: A supporting protrusion fixed to an upper surface of the first frame protrudes from a lower portion of the second frame.

8. The battery pack according to claim 7, wherein: The supporting protrusion is fixed to the first frame by heat fusion.

9. The battery pack according to claim 5, wherein: The second connection portion includes a third frame that is disposed at a position between the adjacent battery cells at a position spaced apart from the first connection portion, and the one of the bus bars is fixed to the third frame.

10. The battery pack according to claim 9, wherein: A second insertion protrusion interposed between the adjacent battery cells protrudes from a lower portion of the third frame.

11. The battery pack according to claim 10, wherein: The one of the bus bars is fixed to the third frame by thermal fusion.

12. The battery pack according to claim 10, wherein: A first end of the buffer connection portion is connected to a side surface of the first frame, a second end of the buffer connection portion is connected to a side surface of the third frame, and a bent portion is formed between the first and second ends of the buffer connection portion, the bent portion having a variable length in the direction perpendicular to the insertion direction.

13. The battery pack according to claim 12, wherein: The bent portion is bent upward below the adjacent battery cells.

14. The battery pack according to claim 12, wherein: Each of the bus bars comprises: a first portion protruding from a first side of the third frame to be electrically connected to a terminal portion of a first battery cell among the adjacent battery cells; and A second portion protrudes from a second side of the third frame to be electrically connected to a terminal portion of a second battery cell among the adjacent battery cells and is formed to have a size different from that of the first portion.

15. The battery pack according to claim 12, wherein: The temperature sensor fixing portion protrudes from one side of one connection portion among the plurality of connection portions.

16. The battery pack according to claim 15, wherein: The temperature sensor fixing portion includes a sensor protrusion portion protruding from a side surface of the second frame of the one connection portion among the plurality of connection portions, and a sensor hole for mounting a temperature sensor is formed in the sensor protrusion portion.

17. The battery pack according to claim 16, wherein: The temperature sensor is installed in the sensor hole of the sensor protrusion and is connected to a cable connected to a protection circuit module.

18. The battery pack according to claim 1, wherein: An insulating sheet is attached to each of the plurality of battery cells.

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