Battery pack

Abstract

The invention relates to a battery pack. A battery pack (11) is provided with a battery cell group (800) in which a plurality of battery cells (701) are arranged, a duct (234) extending along the battery cell group (800), and a bottom surface section (35b) of the duct (234), the bottom surface section (35b) facing the battery cell group and constituting a flow path (780) in combination with the duct (234), the flow path (780) guiding a gas discharged from at least one of the plurality of battery cells (701), and the flow path (780) guiding the gas discharged from at least one of the plurality of battery cells (701). The duct (234) is pressed against the battery cell group (800) across the bottom surface section (35b).

Description

Technical Field

[0001] The present invention relates to batteries. Background Art

[0002] When a secondary battery is used as a power source for an electric vehicle or the like, a plurality of secondary batteries are generally stacked to form a battery pack. The battery pack is loaded into a battery pack for vehicle use. Regarding such a battery pack, for example, the content described in Patent Document 1 is known. [Prior art literature] [Patent Document]

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-4803 Summary of the invention Technical problem to be solved by the invention

[0004] In existing battery packs, the battery cells have exhaust valves that exhaust gas generated from the inside of the battery due to heat. The battery pack has a pipe that is used to guide the gas exhausted from the exhaust valve to the outside of the vehicle cabin, etc. However, in existing battery packs, there is still room for improvement in the airtightness of the pipe. This trend is more obvious when the battery capacity is increased as the performance of electric vehicles improves.

[0005] An object of the present invention is to provide a battery pack which can ensure the airtightness of a gas passage even when gas is exhausted from a battery cell. Technical means of solving problems

[0006] In order to achieve the above-mentioned purpose, the battery pack of the present invention is a battery pack having a battery cell group formed by arranging a plurality of battery cells, the battery pack comprising: a pipe extending along the battery cell group; and a bottom portion of the pipe, the bottom portion facing the battery cell group and combined with the pipe to form a flow path, the flow path guiding the gas discharged from at least one of the plurality of battery cells, the pipe being pressed against the battery cell across the bottom portion. Effects of the Invention

[0007] According to the present invention, it is possible to provide a battery pack capable of maintaining the airtightness of a gas duct even when gas is exhausted from a battery cell. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a three-dimensional view of a battery pack that houses a battery pack. Figure 2 This is an exploded perspective view of the battery pack. Figure 3 This is a perspective view of one embodiment of a battery cell constituting a battery pack. Figure 4It is a perspective view of the appearance of one embodiment of a battery pack. Figure 5 yes Figure 4 An exploded perspective view of a battery pack. Figure 6 It is a perspective view of the assembly structure of the gas duct - first sealing member - bus bar case (bottom portion) - second sealing member - battery cell group. Figure 7 This is a perspective view of one embodiment of a bus bar case (bottom portion). Figure 8 is a perspective view of one embodiment of a gas pipeline. Fig. 9 is a perspective view of a cross section of a first main portion of a battery pack. Fig.10 is a perspective view of a cross section of a second main portion of the battery pack. DETAILED DESCRIPTION

[0009] The embodiments of the present invention are described with reference to the accompanying drawings. In order to facilitate understanding of the embodiments, the sizes and proportions of the components are exaggerated in the accompanying drawings. The same symbols are marked on the same structure. The stacking direction X, width direction Y and height direction Z of the battery pack are indicated by arrows. These directions represent relative positional relationships. That is, when the battery pack is rotated 180 degrees so that the upper surface and the lower surface are reversed, or when the battery pack is rotated 90 degrees so that the upper surface is configured as a side surface, etc., these directions will change.

[0010] The battery pack is formed by fixing a battery cell group formed by arranging a plurality of battery cells on a support body made of metal or the like. A battery cell is also called a single cell. A battery cell is composed of a secondary battery. The battery pack is housed and fixed in a frame to form a battery pack. The battery pack is mounted on a hybrid vehicle driven by an internal combustion engine and an electric motor or an electric vehicle driven by an electric motor, for example, and is used as a power source for the electric motor. Figure 1 It is a perspective view of a battery pack 1 including a battery assembly. Figure 2 It is an exploded perspective view of the battery pack 1 .

[0011] The battery pack 1 is formed by accommodating one or more battery groups 11 ( 11 a , 11 b ) in a hollow box-shaped metal frame 12 . Figure 2 The structure in which two battery packs 11a and 11b are integrated and housed in a frame 12 is shown. The frame 12 includes a metal frame body 12b with a bottom and a flat metal cover 12a. An insertion hole 21a for a cooling pipe 41 is opened near the outer peripheral edge of the cover 12a. The insertion hole 21a is used to insert a cooling pipe 41 for heat dissipation, and the cooling pipe 41 is provided in a fixing member 41a that fixes the battery packs 11a and 11b.

[0012] By providing the insertion hole 21a of the cooling duct 41 in the cover 12a, when the cover 12a is closed with the battery pack 11 (11a, 11b) accommodated in the interior of the frame body 12b, the cover 12a can close the open end of the frame body 12b without interfering with the cooling duct 41. Thus, the interior of the frame 12 can be sealed.

[0013] In the battery pack 1, the frame 12 and the battery pack 11 are fixed to each other by various metal fixing members such as conductive bolts and washers. A hole 220 for inserting a bolt (not shown) is provided at the bottom of the frame body 12b, and the bolt is used to assemble the battery packs 11a and 11b to the frame body 12b in the Z direction.

[0014] The frame 12 is provided with an insulating cover 13. The insulating cover 13 is a rectangular cylindrical resin container with a bottom having insulating properties. The insulating cover 13 is inserted into the frame body 12b in a manner of being in close contact with the inner surface of the frame body 12b. As a result, most of the inner surface of the bottom of the frame 12 is insulated. A rectangular opening 310 for inserting a bolt is formed on the bottom surface of the insulating cover 13, and the rectangular opening 310 is used to fix the battery pack 11 on the bottom surface of the frame body 12b.

[0015] An exhaust port (341a, 341b) is provided near one end of an exhaust duct (243a, 243b) of a battery pack (11a, 11b). An exhaust pipe 201 is connected to each of the exhaust ports (341a, 341b). The exhaust port (341a, 341b) and the exhaust pipe 201 are connected, for example, by a joint made of resin.

[0016] The exhaust pipe 201 and the exhaust duct (243a, 243b) together complete the task of exhausting the gas generated inside each secondary battery described later to the outside of the vehicle cabin. Therefore, the exhaust pipe 201 reaches the battery pack 11 side via the insulating cover 13 and the insertion holes 203, 203a pre-set in the frame body 12b. The end of the exhaust pipe 201 on the opposite side of the battery pack 11 extends to the outside of the frame 12 and is connected to the exhaust hole (not shown) that connects the inside and outside of the vehicle cabin.

[0017] Gas generated in at least one of the plurality of battery cells constituting the battery pack (11a, 11b) passes through the interior of the exhaust duct (243a, 243b) to reach the exhaust port (341a, 341b), and further passes through the interior of the exhaust pipe 201 to be discharged outside the vehicle cabin.

[0018] The following is an explanation of the implementation of the battery pack 11. Figure 3The battery cell 701 constituting the battery pack 11 is described. The battery cell 701 includes a battery can 702, a battery cover 703, a positive terminal 704, a negative terminal 705, a vent valve 706, a liquid injection plug 707, an electrolyte solution (not shown), a charge and discharge element, and an insulating cover. The vent valve 706 is provided at the center of the battery cover 703 in the Y direction. A rechargeable secondary battery such as a lithium ion secondary battery is used as the battery cell 701.

[0019] The battery can 702 has a rectangular parallelepiped shape with one end of the internal space open, and is made of aluminum or aluminum alloy. The battery can 702 has a pair of opposing side plates 702a with a larger area, a pair of opposing side plates 702b with a smaller area, and a bottom plate 702c on the opposite side of the opening. In the internal space of the battery can 702, the charge and discharge element is accommodated in a state covered by an insulating cover, and the electrolyte is injected into the internal space of the battery can 702. The positive electrode of the charge and discharge element is connected to the positive terminal 704, and the negative electrode of the charge and discharge element is connected to the negative terminal 705.

[0020] The battery cover 703 has a rectangular flat plate shape similar to the bottom plate 702c, is made of aluminum or aluminum alloy, and closes the opening of the battery can 702. The battery cover 703 is joined to the opening of the battery can 702 by a joining means such as laser welding. A through injection hole (not shown) is formed in the battery cover 703, and the electrolyte is injected from the injection hole, and the injection hole is closed by an injection plug 707.

[0021] A vent valve 706 is provided at the center of the battery cover 703. When the battery cell 701 generates heat and gas due to an abnormality such as overcharging, and the pressure inside the battery can 702 rises and reaches a specified pressure, the vent valve 706 is opened to discharge gas from the container, thereby reducing the pressure inside the battery can 702.

[0022] In addition, through holes (not shown) are formed at one end and the other end of the battery cover 703, and a positive terminal 704 and a negative terminal 705 are installed. The portions of the positive terminal 704 and the negative terminal 705 exposed to the outside from the battery cover 703 are each formed into a rectangular parallelepiped and have a flat top surface. The power generated by the battery cell 701 is supplied to an external device via the positive terminal 704 and the negative terminal 705, or the power generated externally is supplied to the charging and discharging element via the positive terminal 704 and the negative terminal 705 for charging.

[0023] Next, the battery pack 11 will be described. Figure 4 This is a three-dimensional diagram of the appearance of the battery pack. Figure 5 This is an exploded perspective view of the battery pack. Figure 4As shown, the battery pack 11 includes a block assembly 1100 and a busbar housing assembly 1200. The block assembly 1100 includes a collection of multiple battery cells (battery cell group) 800 and a reinforcing member 800a of the battery cell group. The battery cell group 800 is an integrated structure reinforced by the reinforcing member 800a. The battery cell group can also be expressed as a laminate or stack.

[0024] The battery cell group 800 is formed by connecting a plurality of battery cells 701 to a side plate 702a ( Figure 3 ) are opposite to each other, and the bottom plate 702c is used as the bottom, and the spacers 721 are sandwiched between the battery cells and arranged in one direction (stacking direction X). A first end spacer 23 is installed on one end side of the battery cell group 800, and a second end spacer 22 is installed on the other end side.

[0025] The spacer 721 is made of a synthetic resin having insulating properties. The spacer 721 has recesses on both sides thereof corresponding to the shape of the battery cell 701, and the recesses are used to hold the battery cell 701 and restrict the Y direction and the Z direction. In addition, as described later, a claw portion 324 ( Fig.10 ), designed to be connected to the hook 343 ( Figure 8 ) snap into place.

[0026] The first end spacer 23 has insulating properties and is made of a synthetic resin harder than the spacer 721, and is arranged to be adjacent to the battery cell 701 located at the end of one direction side in the stacking direction. The first end spacer 23 has a recess corresponding to the battery cell 701 on the opposite surface facing the battery cell 701, and the battery cell 701 is held by the recess and the Y direction and the Z direction are restricted. A fixing bolt hole 23a, a positive electrode connection terminal 23b, and a fixing hole 23d for the exhaust duct are formed on the side of the first end spacer 23 facing the end plate 26.

[0027] The second end spacer 22 is insulating and made of a synthetic resin harder than the spacer 721, and is arranged to be opposite to the battery cell 701 at the end on the other side of the stacking direction. The second end spacer 22 has a recess corresponding to the shape of the battery cell 701 on the opposite surface opposite to the battery cell 701, and the battery cell 701 is held by the recess and the Y direction and Z direction are restricted. In addition, a fixing bolt hole (not shown) and a negative electrode connection terminal 22b are provided on the side of the second end spacer 22 opposite to the end plate. In addition, a fixing bolt hole 22d for fixing each component is formed in the upper part of the second end spacer 22 in the Z direction.

[0028] The reinforcing member 800a includes a pair of side rails 24 and 25, a pair of end plates 26 (the end plate on the second end spacer 22 side is not shown), and a plurality of bolts 28. The side rail 24 is formed of a metal material, and includes a rail body 24c extending in the X direction and bent portions 24b bent in the Y direction and facing each other at both ends of the rail body 24c, and each bent portion 24b is provided with a fixing hole 24a penetrating in the X direction. The bent portion 24b is arranged to face the second end spacer 22 and the first end spacer 23 from the outside in the stacking direction, and covers a portion of the second end spacer 22 and a portion of the first end spacer 23.

[0029] The side rails 24 press the second end spacer 22, the plurality of battery cells 701, the plurality of spacers 721, and the first end spacer 23 in the stacking direction and hold and fasten them in this state. Bolts 28 are inserted through the fixing holes 24a of the bent portions 24b, and the side rails 24 are fixed to the end plates 26 (the end plates on the second end spacer 22 side are not shown in the figure).

[0030] The side rail 25 is formed of the same metal material as the side rail 24 and has the same function as the side rail 24. The side rail 25 is arranged to face the side rail 24 in the Y direction with the stacked battery cells 701 interposed therebetween, and includes a rail body 25c extending in the X direction, and bent portions 25b bent in the Y direction and facing each other at both ends of the rail body 25c. The bent portion 25b has a fixing hole 25a through which a bolt 28 is inserted.

[0031] The end plate 26 is formed of a plate-shaped metal material, that is, a metal sheet, and is arranged adjacent to the first end spacer 23. The end plate 26 has a flat portion 26a and a fixing portion 26b, the flat portion 26a having a through hole formed therein for positioning the first end spacer 23, and a fixing portion 26b for fixing the side rails 24 and 25. The fixing portion 26b has a fixing hole 26c through which a bolt 28 is inserted. The fixing portion 26b has a drop that is recessed in the stacking direction relative to the flat portion 26a, and is configured so that when the bent portions 24b and 25b of the side rails 24 and 25 are tightened by the bolt 28, the head of the bolt does not protrude from the surface of the flat portion 26a. A nut is mounted on the fixing portion 26b. The second end spacer 22 side is configured in the same manner.

[0032] The end plate on the second end spacer 22 side is formed similarly to the end plate 26 and is disposed adjacent to the second end spacer 22. The end plate, the side rail 24, and the bent portions 24b and 25b of the side rail 25 are fastened by bolts 28.

[0033] The busbar housing assembly 1200 includes a busbar 31, a wiring harness, an exhaust duct 234, a plurality of covers 34, and a busbar housing 35. The busbar housing assembly 1200 has functions such as electrically connecting the terminals of the battery cells 701 and the controller, monitoring voltage and temperature, and exhausting gas.

[0034] The bus bar 31 includes an inter-cell bus bar 31a, a negative bus bar 31b, or a positive bus bar 31c, and is housed in a bus bar case 35. The inter-cell bus bar 31a electrically connects the positive terminal 704 and the negative terminal 705 of the battery cell 701. The negative bus bar 31b is connected to the first end spacer 23, and the positive bus bar 31c is connected to the second end spacer 22.

[0035] The bus bar housing 35 is made of insulating resin. The bus bar housing 35 has a plurality of frames 35a arranged side by side on both sides in the width direction along the stacking direction of the battery cells 701, and the inter-cell bus bar 31a, the negative bus bar 31b, and the positive bus bar 31c are accommodated in the frames. A substrate portion 35b mounted on the battery cell group 800 is formed on the surface of the bus bar housing 35 on the battery cell group 800 side.

[0036] The exhaust duct 234 is a duct described in the technical solution, made of resin, facing the battery cell group 800, and extending above the battery cell group in the X direction and having a certain length. The exhaust duct 234 is fixed to the second end spacer 22 and the nut of the first end spacer 23 by bolts arranged at both ends in the X direction. The multiple covers 34 have the function of insulating and protecting the components of the busbar housing assembly 1200, and are configured to cover the busbar 31 and the wiring harness. Each cover 34 is fitted into the busbar housing 35 and fixed.

[0037] The exhaust duct 234 is extended in the X direction and has a tunnel shape with the battery cell group 800 side open along the X direction. Figure 6 As shown, the exhaust duct 234 is combined with the substrate portion 35b so that the open portion of the exhaust duct 234 is covered by the busbar housing 35 (substrate portion 35b) on the plane of the battery cell group 800. That is, the flange portion (234f, 234g) of the periphery of the exhaust duct 234 is supported by the periphery of the substrate portion 35b, and as a result, a tunnel-shaped isolated space oriented in the X direction is formed. This is the gas flow path 780 ( Fig. 9 , Fig.10 The substrate portion 35b is a surface facing the battery cell group 800 and is an example of the bottom surface described in the claims.

[0038] The exhaust duct 234 isolates and collects the gas exhausted from the exhaust valve 706 of at least one battery cell 701 of the battery cell group 800 at the center in the width direction (Y direction), guides the gas in the X direction in the gas flow path 780 , and exhausts the gas from the exhaust port 233 .

[0039] The base plate portion 35b serves as the bottom portion of the exhaust duct 234 and supports the exhaust duct 234 along the X direction relative to the battery cell group 800. Figure 3 As shown, the gas flow path 780 has a width WT that can cover the exhaust valve 706 in the Y direction, and is extended along the X direction. The exhaust valve 706 of each battery cell 701 in the battery cell group 800 is connected to the exhaust flow path 780 .

[0040] In order to improve the airtightness of the gas flow path 780, the exhaust duct 234 is pressed against the battery cell group 800 via the substrate portion 35b in the X direction and connected. As a result, the first sealing member 245 ( Figure 6 ) is compressed, thereby improving the sealing performance and suppressing the gas leakage from the exhaust flow path 780. In addition, the second sealing member 246 ( Figure 6 ) is strongly compressed, thereby preventing the gas discharged from the exhaust valve 706 from bypassing the exhaust flow path 780.

[0041] The exhaust duct 234 and the substrate portion 35b are pressed against the battery cell group 800, thereby improving the rigidity of the gas flow path 780. Even if the battery pack 11 is subjected to physical stress such as vibration and shaking when the vehicle is running, deformation such as displacement and looseness of the exhaust flow path 780 can be suppressed, and the sealing performance against gas leakage can be improved by combining with the sealing component. As one way of pressing, the exhaust duct 234 is engaged toward the battery cell group 800 via the substrate portion 35b. One way of the structure for engagement is as follows.

[0042] The spacer 721 and the end spacers 22 and 23 of the battery cell group 800 each have a pair of claws (hooks) 342 ( Fig.10 ).like Figure 8 As shown, the exhaust duct 234 is provided with hooks 343, 343a as the engaged portion on the side surface 234t in the X direction. A plurality of hooks 343 are arranged on the side surface 234t of the exhaust duct 234 at a certain interval in the X direction, so that the plurality of hooks 343 are opposite to each claw portion 342 of the plurality of spacers 721, 22, 23. Each hook 343a at both ends of the side surface 234t in the X direction corresponds to each claw portion of the end spacers 22, 23.

[0043] When the exhaust duct 234 is pressed against the battery pack 800, the pair of claws 342 of the spacers 721, 22, 23 engage with the hooks 343, 343a of the exhaust duct 234. As a result, the exhaust duct 234 is supported by the base plate 35b and is strongly pressed against the battery cell pack 800 via the base plate 35b in the X direction for fixation.

[0044] like Fig.10 As shown, the claws 342 protrude at right angles from the end faces of the spacers 721, 22, and 23 in the Z direction. A pair of claws 342 are symmetrically provided at the center of the spacers in the Y direction. The claws 342 may be provided on all the spacers 721 and / or the end spacers 22 and 23. A plurality of hooks 343 are provided in the exhaust duct 234 to match the number and position of the claws of the spacers. Figure 8 As shown, each of the plurality of hooks 343 is bent from the lower end of the exhaust duct 234 in the Z direction and is protruded toward the battery cell group 800. The hook 343 is composed of a substantially U-shaped arm 343d. Figure 8 and Fig.10 As shown, the claw portion 342 is fitted into the recess 343c on the inner side of the arm and engages with the lower end 343b of the arm.

[0045] In order to make multiple fixing means composed of claws 342 (engaging elements) and hooks 343 (engaged elements) equally present on each side of the battery cell group 800 in the Y direction, the exhaust duct 234 and the base plate 35b are pressed against the battery cell group 800, so that the exhaust flow path 780 can be constructed with high rigidity in the X direction. It should be noted that although the claws are used as the engaging elements and the hooks are used as the engaged elements, they can also be called the reverse.

[0046] The spacers provided with the claws 342 may be part of all the spacers. In the case where a part of the spacers are provided with claws, the spacers that should have claws are selected in the X direction of the battery cell group 800 so that the positions and numbers of the claws on both sides of the Y direction are symmetrical. By providing the claws 342 in the end spacers 22 and 23, the gas flow path 780 can withstand the high pressure caused by the turbulence at both ends of the gas flow path 780 in the X direction.

[0047] The base plate portion 35b is provided with a plurality of openings 35c facing each exhaust valve 706 of the plurality of battery cells 701 so as not to interfere with the exhaust valve 706 ( Figure 6 , 7 , 9, 10). The opening 35c is formed to be larger than the area of ​​the exhaust valve 706 ( Figure 3 , 9 ) so as not to hinder the gas from flowing out of the exhaust valve 706 to the gas flow path 780.

[0048] The periphery of the substrate portion 35b of the exhaust duct 234 at both ends in the Y direction is provided with flanges 234f bent at right angles along the X direction, and the periphery of the substrate portion 35b of the exhaust duct 234 at both ends in the X direction is provided with flanges 234g bent at right angles along the Y direction. Figure 6 , 8 , 10). At the joint surface between the flanges 234f, 234g and the base plate portion 35b, the first sealing member 245 is compressed, clamped and fixed ( Figure 6 , 10 ). The first sealing member 254 extends in the X direction along the exhaust duct 234. Therefore, leakage of gas from the entire circumference of the joining surface of the gas flow path 780 to the outside of the gas flow path 780 is suppressed.

[0049] like Fig. 9 As shown, the substrate portion 35b has a recessed portion 344 on the battery cell group 800 (battery cell 701) side, and the second sealing member 246 ( Figure 6 When the substrate portion 35b is pressed against the battery cell group 800, the second sealing member 246 is compressed in the recess 344 and is sandwiched and fixed between the substrate portion 35b and the battery cell group 800. Therefore, the second sealing member 246 around the exhaust valve 706 seals the exhaust valve 706 except for the gas flow path 780.

[0050] In order to sandwich the second sealing member 246 between the substrate portion 35b and the battery cell group 800, the second sealing member 246 has an opening 246c ( Figure 6 ). In order to align the two openings 35c and 246c, the second sealing member 246 is embedded in the recess 344 on the battery cell group 800 side of the substrate portion 35b. With the first sealing member 245 and the second sealing member, the gas exhausted from the exhaust valve 706 is guided along the gas flow path 780 without leaking from the gas flow path 780.

[0051] The sealing components 245 and 246 may be compressible resin elastomers such as polyurethane, polypropylene, EPDM, rubber, etc. The sealing components are bonded and fixed to the opposing surface by double-sided tape, adhesive material, etc. Since the sealing components are compressed and fixed to the opposing surface, the rigidity of the sealing portion can be improved. With the rigidity of the sealing portion and the engagement between the claw portion 342 and the hook 343, the rigidity of the gas flow path is improved. As a result, even if the battery pack is subjected to stress due to the movement of the vehicle, etc., the occurrence of deviation and looseness of the gas flow path can be suppressed, thereby maintaining the sealing performance.

[0052] like Fig.10As shown, in the width direction (Y direction) of the exhaust duct 234, compared with the lower end 343b ( Figure 8 ) engagement position, the position where the first sealing member 245 is clamped between the exhaust duct 234 and the substrate portion 35b is closer to the center of the width direction (Y direction) of the battery cell 701. Furthermore, in the height direction (Z direction) of the exhaust duct 234, compared with the position where the first sealing member 245 is clamped between the exhaust duct 234 and the substrate portion 35b, the claw portion 342 and the lower end 343b ( Figure 8 ) is closer to the battery cell 701. As a result, after the first sealing member 245 is positioned, even when a plurality of claws 342 and hooks 343 must be engaged with each other in order to engage the claws 342 with the hooks 343, the battery pack 11 can accurately engage each one without deviation.

[0053] As the first sealing member 245 and the second sealing member 246, polyurethane foam (PORON (trademark)) with a fine and uniform cell structure is preferred. It has very small compression residual strain, excellent sealing performance, and excellent energy absorption. Even if stress is applied to the sealing portion, the risk of impairing the sealing performance is low due to the high rigidity of the sealing portion.

[0054] According to the above embodiment, the following battery pack is provided. The first battery pack 11 is characterized in that it includes a battery cell group 800 in which a plurality of battery cells 701 are arranged, and further includes a duct 234 extending along the battery cell group 800 and a bottom portion 35b of the duct 234, the bottom portion 35b facing the battery cell group 800 and forming a flow path 780 in combination with the duct 234, the flow path 780 guiding gas exhausted from at least one of the plurality of battery cells 701, and the duct 234 being pressed against the battery cell group 800 via the bottom portion 35b.

[0055] According to the first battery pack, the first sealing member 245 can be provided on the joint surface between the duct 234 and the bottom surface portion 35b, and the bottom surface portion 35b is arranged on the battery cell group 800 via the second sealing member 246. Therefore, the rigidity of the sealing surface involved in the flow path 780 for guiding the gas is improved along the battery cell group 800, and the sealing performance of the flow path 780 is improved by the second sealing member 246 in addition to the first sealing member 245, so that a battery pack without the risk of leakage of gas discharged from the battery cell can be provided.

[0056] The second battery pack is characterized in that, in the first battery pack, the bottom surface portion 35b is the surface of the bus bar case 35 facing the battery cell group 800. According to the second battery pack, the bus bar case 35 is used, thereby providing a battery pack without the risk of gas leakage from the battery cells.

[0057] The third battery pack is characterized in that, in the first battery pack, the duct 234 engages with the battery cell group 800 via the bottom surface 35b. According to the third battery pack, the duct 234 engages with the battery cell group 800 while being supported by the bottom surface 35b, so that the rigidity of the sealing portion of the flow path 780 can be further improved.

[0058] The fourth battery pack is characterized in that, in the third battery pack, each of the plurality of battery cells 701 of the battery cell group 800 is stacked on top of each other via a spacer 721, the spacer 721 includes an engagement portion 342 protruding toward the duct 234, and the engagement portion 342 engages with the duct 234. According to the fourth battery pack, the duct 234 is strongly pressed against the battery cell group 800.

[0059] The fifth battery pack is characterized in that, in the fourth battery pack, the engaging portion 342 is provided in all the spacers 721 arranged between the plurality of battery cells of the battery cell group 800. According to the fifth battery pack, the rigidity and sealing property of the flow path 780 are improved along the entire length of the flow path 780.

[0060] The sixth battery pack is characterized in that, in the fourth battery pack, the battery cell group 800 has end spacers 22 and 23 at the ends in the direction in which the plurality of battery cells 701 are stacked, and the end spacers have a snap-fitting portion. According to the sixth battery pack, the sealing property can be improved for gas turbulence that may occur at the ends of the flow path 780 in the longitudinal direction.

[0061] The seventh battery pack is characterized in that, in the first battery pack, the duct 234 and the bottom surface 35b form a joint surface at their respective peripheral portions, and the first sealing member 245 is compressed and clamped by the duct 234 and the bottom surface 35b. According to the seventh battery pack, the sealing performance of the flow path 780 can be improved over the entire circle.

[0062] The eighth battery pack is characterized in that, in the first battery pack, each of the plurality of battery cells 701 of the battery cell group 800 has an exhaust valve 706, and the bottom portion 35b and the second sealing member 246 respectively have openings 35c and 246c ( Figure 6), the second sealing member 246 is compressed and clamped by the substrate portion 35b and the battery cell 701 at the portion other than the opening. According to the eighth battery pack, the outflow of gas from the opening to the flow path 780 can be improved while the sealing of the flow path 780 is improved. The size of the opening 35c, 246c is larger than the area of ​​the exhaust valve 706, or when the opening is reduced for reasons such as improving the rigidity of the structure, the size of the opening 35c, 246c is at least 80% of the area of ​​the exhaust valve 706.

[0063] The ninth battery pack is characterized in that, in the fourth invention, in the width direction of the pipe 234, the position where the first sealing part 245 is clamped between the pipe 234 and the bottom surface part 35b is closer to the center of the battery cell 701 than the position where the clamping part 342 is clamped with the pipe 234. The tenth battery pack is characterized in that, in the fourth invention, in the height direction of the pipe 234, the position where the clamping part 342 is clamped with the pipe 234 is closer to the battery cell 701 than the position where the first sealing part 245 is clamped between the pipe 234 and the bottom surface part 35b.

[0064] Therefore, after the first sealing member 245 is positioned, even when a plurality of claws 342 and hooks 343 must be engaged with each other in order to fit the claws 342 into the hooks 343 , the battery pack 11 can accurately perform each engagement without deviation.

[0065] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and various design changes can be made as long as they do not deviate from the technical ideas of the present invention recorded in the claims. For example, in order to understand the present invention in a simple and easy way, the above embodiments are described in detail, but they are not necessarily limited to having all the above structures. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and the structure of other embodiments can also be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can be added, deleted or replaced. Description of Reference Numerals

[0066] 11: battery pack; 35b: bottom portion; 234: duct; 245: first sealing member; 246: second sealing member; 701: battery cell; 780: flow path; 800: battery cell pack.

Claims

1. A battery pack comprising a battery cell group formed by arranging a plurality of battery cells, characterized in that: have: A pipe extending along the battery cell group; and The bottom surface of the duct faces the battery cell group and is combined with the duct to form a flow path, the flow path guiding the gas exhausted from at least one of the plurality of battery cells. The duct is pressed against the battery cell group via the bottom surface portion.

2. The battery pack according to claim 1, characterized in that: The first sealing member is arranged on the joint surface between the pipe and the bottom surface portion. The bottom surface portion is disposed on the battery cell group via a second sealing member.

3. The battery pack according to claim 1, characterized in that: The bottom surface portion is a surface of the bus bar case that faces the battery cell group.

4. The battery pack according to claim 1, characterized in that: The duct is engaged with the battery cell group via the bottom surface portion.

5. The battery pack according to claim 4, characterized in that: Each of the plurality of battery cells of the battery cell group is stacked on top of each other via a spacer, The spacer includes a locking portion that protrudes toward the pipe. The engaging portion is engaged with the pipeline.

6. The battery pack according to claim 5, characterized in that: The engaging portion is provided on all of the spacers arranged between the plurality of battery cells of the battery cell group.

7. The battery pack according to claim 5, characterized in that: The battery cell group includes an end spacer at an end portion in a direction in which the plurality of battery cells are stacked, and the end spacer has the engaging portion.

8. The battery pack according to claim 1, characterized in that: The pipe and the bottom surface portion form the joining surface at their respective peripheral edges. The first sealing member is compressed and held by the pipe and the bottom surface portion.

9. The battery pack according to claim 1, characterized in that: Each of the plurality of battery cells in the battery cell group includes a gas exhaust valve. The bottom surface portion and the second sealing member each have an opening that does not hinder the outflow of gas from the exhaust valve. The second sealing member is compressed and sandwiched by the bottom surface portion and the battery cell at a portion other than the opening.

10. The battery pack according to claim 5, characterized in that: In the width direction of the duct, a position where the first sealing member is sandwiched between the duct and the bottom surface portion is closer to the center of the battery cell than a position where the engaging portion engages with the duct.

11. The battery pack according to claim 5, characterized in that: In the height direction of the duct, a position where the engaging portion engages with the duct is closer to the battery cell than a position where the first sealing member is sandwiched between the duct and the bottom surface portion.

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