Battery pack

Abstract

This battery pack 11 comprises: a duct 234 that is provided with a battery cell group 800 in which a plurality of battery cells 701 are arranged, the duct 234 extending along the battery cell group 800; and a bottom-surface part 35b of the duct 234 that faces the battery cell group 800 and is combined with the duct 234 to constitute a flow path 780 via which a gas discharged from at least one of the plurality of battery cells 701 is guided, the duct 234 being pressed against the battery cell group 800 via the bottom-surface part 35b.

Description

Technical Field

[0001] The present invention relates to a battery pack.

Background Art

[0002] When a secondary battery is used as a power supply source for an electric vehicle or the like, it is common practice to stack a plurality of secondary batteries to form a battery pack. The battery pack is incorporated into a vehicle-mounted battery pack for use. Regarding such a battery pack, for example, the one described in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described battery pack, the battery cell has a gas discharge valve for discharging gas generated from inside the battery due to heat generation. The battery pack has a duct for guiding the gas discharged from the gas discharge valve to the outside, such as outside the vehicle compartment of an automobile. However, in the conventional battery pack, there is room for improvement in the airtightness of the duct. This tendency becomes more prominent when trying to increase the battery capacity in response to performance improvement of an electric vehicle or the like.

[0005] An object of the present invention is to provide a battery pack that can maintain the airtightness of a gas duct even when gas is discharged from a battery cell.

Means for Solving the Problems

[0006] To achieve the above objective, the present invention provides a battery pack comprising a group of battery cells arranged in a plurality of battery cells, the battery pack comprising: a duct extending along the group of battery cells; and a bottom surface of the duct facing the group of battery cells and, in combination with the duct, forming a flow path for guiding gas discharged from at least one of the plurality of battery cells, wherein the duct is pressed against the group of battery cells via the bottom surface. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a battery pack that can maintain the airtightness of the gas duct even when gas is discharged from the battery cells. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of a battery pack that houses a battery pack. [Figure 2] This is a perspective view of a disassembled battery pack. [Figure 3] This is a perspective view of one embodiment of a battery cell constituting a battery pack. [Figure 4] This is an external perspective view of one embodiment of a battery pack. [Figure 5] Figure 4 is a disassembled perspective view of the battery pack. [Figure 6] This is a perspective view relating to the assembly structure of the gas duct, the first sealing member, the busbar case (bottom surface), the second sealing member, and the battery cell group. [Figure 7] This is a perspective view of one embodiment of a bus case (bottom section). [Figure 8] This is a perspective view of one embodiment of a gas duct. [Figure 9] This is a perspective view of the first essential cross-section of the battery pack. [Figure 10] This is a perspective view of the cross-section of the second main part of the battery pack. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding of the embodiments, the size and proportions of the components may be exaggerated in the drawings. The same reference numerals are used for identical components. The stacking direction X, width direction Y, and height direction Z of the battery pack are indicated by arrows. These directions indicate the relative positional relationship. That is, these directions will change if the battery pack is rotated 180 degrees and the top and bottom surfaces are reversed, or if the battery pack is rotated 90 degrees and the top surface becomes the side surface.

[0010] A battery pack is constructed by fixing a group of battery cells, each arranged in a row, with a support made of metal or other material. A battery cell is also referred to as a single cell. A battery cell is made up of secondary batteries. The battery pack is housed and fixed in a casing to form a battery pack. Battery packs are installed, for example, in hybrid vehicles driven by an internal combustion engine and an electric motor, or in electric vehicles driven by an electric motor, and are used as a power source for the motor. Figure 1 is a perspective view of a battery pack 1 containing a battery pack. Figure 2 is an exploded perspective view of the battery pack 1.

[0011] The battery pack 1 is constructed by housing one or more battery packs 11 (11a, 11b) in a hollow, box-shaped metal housing 12. Figure 2 shows two battery packs 11a and 11b integrated and housed in the housing 12. The housing 12 comprises a bottomed, metal housing body 12b and a flat, metal lid 12a. An insertion hole 21a for a cooling duct 41 is opened near one edge of the outer circumference of the lid 12a. This insertion hole 21a is for inserting a heat dissipation cooling duct 41 installed on a fixing member 41a that secures the battery packs 11a and 11b.

[0012] Since the lid 12a is provided with an insertion hole 21a for the cooling duct 41, when the lid 12a is closed with the battery pack 11 (11a, 11b) housed inside the housing body 12b, the lid 12a can be closed without interfering with the cooling duct 41, thereby sealing the inside of the housing body 12.

[0013] In the battery pack 1, the housing 12 and the assembled battery 11 are fixed to each other by various metal fixing members such as bolts and washers having conductivity. A hole 220 through which a bolt (not shown) for assembling the assembled batteries 11a and 11b in the Z direction with respect to the housing body 12b is provided at the bottom of the housing body 12b.

[0014] The housing 12 includes an insulating case 13. The insulating case 13 is a resin container having a bottomed rectangular tube shape with insulation properties. The insulating case 13 is inserted into the housing body 12b so as to be in close contact with the inner surface of the housing body 12b. Thereby, most of the inner surface of the bottom of the housing 12 is insulated. A rectangular opening 310 through which a bolt for fixing the assembled battery 11 to the bottom surface of the housing body 12b is inserted is formed on the bottom surface of the insulating case 13.

[0015] Near one end of the gas discharge ducts (243a, 243b) of the assembled batteries (11a, 11b), gas discharge ports (341a, 341b) are provided. And a gas discharge tube 201 is connected to each of the gas discharge ports (341a, 341b). The gas discharge ports (341a, 341b) and the gas discharge tube 201 are connected by, for example, a joint made of resin.

[0016] The gas discharge tube 201, together with the gas discharge ducts (243a, 243b), serves to discharge the gas generated inside each secondary battery described later to the outside of the vehicle cabin. Therefore, the gas discharge tube 201 extends to the side of the assembled battery 11 through insertion holes 203 and 203a provided in advance in the insulating case 13 and the housing body 12b. The end of the gas discharge tube 201 opposite to the assembled battery 11 extends outside the housing 12 and is connected to a gas discharge hole (not shown) that communicates the inside and outside of the vehicle cabin.

[0017] The gas generated in at least one of the plurality of battery cells constituting the assembled batteries (11a, 11b) reaches the gas discharge ports (341a, 341b) through the inside of the gas discharge ducts (243a, 243b), and further passes through the inside of the gas discharge tube 201 and is discharged to the outside of the vehicle cabin.

[0018] Hereinafter, an embodiment of the assembled battery 11 will be described. First, the battery cell 701 constituting the assembled battery 11 will be described with reference to FIG. 3. The battery cell 701 has a battery can 702, a battery lid 703, a positive electrode terminal 704, a negative electrode terminal 705, a gas discharge valve 706, a liquid injection plug 707, an electrolyte (not shown), a charge / discharge element, and an insulating case. The gas discharge valve 706 is provided at the center of the battery lid 703 in the Y direction. A rechargeable secondary battery such as a lithium-ion secondary battery is used for 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 an aluminum alloy. The battery can 702 has a pair of opposing side plates 702a with a large area, a pair of opposing side plates �02b with a small area, and a bottom plate 702c on the side opposite to the opening. In the internal space of the battery can 2, the charge / discharge element is housed in a state covered by the insulating case, and the electrolyte is injected. The positive electrode of the charge / discharge element is connected to the positive electrode terminal <004, and the negative electrode of the charge / discharge element is connected to the negative electrode terminal 705.

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

[0021] A gas discharge valve 706 is provided at the central portion of the battery lid 703. The gas discharge valve 706 is opened when the battery cell 701 generates heat due to an abnormality such as overcharging and generates gas, and the pressure inside the battery can 702 rises to reach a predetermined pressure, and discharges the gas from the inside of the container to reduce the pressure inside the battery can 702.

[0022] Furthermore, 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 attached to them. The portions of the positive terminal 704 and the negative terminal 705 that are exposed to the outside from the battery cover 703 are each formed as rectangular parallelepipeds and have a flat top surface. Power generated by the battery cell 701 is supplied to external devices via the positive terminal 704 and the negative terminal 705, or power generated externally is supplied to the charging / discharging element via the positive terminal 704 and the negative terminal 705 to charge it.

[0023] Next, the battery pack 11 will be described. Figure 4 is a perspective view of the battery pack's appearance, and Figure 5 is an exploded perspective view of the battery pack. As shown in Figure 4, the battery pack 11 consists of a block assembly 1100 and a busbar case assembly 1200. The block assembly 1100 consists of a collection of multiple battery cells (battery cell group) 800 and a reinforcing member 800a for the battery cell group. The battery cell group 800 has an integrated structure reinforced by the reinforcing member 800a. The battery cell group may also be described as a laminate or stack.

[0024] The battery cell group 800 consists of multiple battery cells 701 arranged in one direction (stacking direction X) with their side plates 702a (Figure 3) facing each other and the bottom plate 702c at the bottom, with spacers 721 in between each battery cell. A first end spacer 23 is attached to one end of the battery cell group 800, and a second end spacer 22 is attached to the other end.

[0025] The spacer 721 is made of an insulating synthetic resin. The spacer 721 has recesses on both sides that correspond to the shape of the battery cell 701, and these recesses hold the battery cell 701 and restrict its movement in the Y and Z directions. Furthermore, as will be described later, the spacer 721 is provided with a claw portion 324 (Figure 10) on the upper part in the Z direction, which engages with a hook 343 (Figure 8) provided on the gas exhaust duct 234.

[0026] The first end spacer 23 is made of a synthetic resin that is insulating and harder than the spacer 721, and is positioned adjacent to the battery cell 701 located at the end on one side of the stacking direction. The first end spacer 23 has a recess on the opposing surface facing the battery cell 701 that corresponds to the battery cell 701, and the recess holds the battery cell 701 and restricts its movement in the Y and Z directions. On the side of the first end spacer 23 facing the end plate 26, there are fixing bolt holes 23a, a positive electrode connection terminal 23b, and a fixing hole 23d for a gas exhaust duct.

[0027] The second end spacer 22 is made of a synthetic resin that is insulating and harder than the spacer 721, and is positioned opposite the battery cell 701 located at the other end in the stacking direction. The second end spacer 22 has a recess on the opposing surface facing the battery cell 701 that corresponds to the shape of the battery cell 701, and the recess holds the battery cell 701 and restricts its movement in the Y and Z directions. 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 facing the end plate. Furthermore, a fixing bolt hole 22d for fixing each component is formed on 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 made of a metal material and has a rail body 24c extending in the X direction and bent portions 24b that are bent in the Y direction at both ends of the rail body 24c and face each other. Each bent portion 24b is provided with a fixing hole 24a that penetrates in the X direction. The bent portions 24b are positioned facing the second end spacer 22 and the first end spacer 23 from the outside in the stacking direction and cover a part of the second end spacer 22 and a part of the first end spacer 23.

[0029] The side rail 24 holds and secures the second end spacer 22, the multiple battery cells 701, the multiple spacers 721, and the first end spacer 23 in a state of being pressed in the stacking direction. The side rail 24 is fixed to the end plate 26 (the end plate on the second end spacer 22 side is not shown) by inserting a bolt 28 through the fixing hole 24a of the bent portion 24b.

[0030] The side rail 25 is made 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 positioned opposite the side rail 24 in the Y direction, with the stacked battery cells 701 in between, and has a rail body 25c that extends in the X direction and bent portions 25b that are bent in the Y direction at both ends of the rail body 25c and face each other. The bent portions 25b have fixing holes 25a through which bolts 28 are inserted.

[0031] The end plate 26 is made of a plate-shaped metal material, so-called sheet metal, and is positioned adjacent to the first end spacer 23. The end plate 26 has a flat portion 26a with a through hole for positioning relative to 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 step recessed in the stacking direction relative to the flat portion 26a, so that when the bent portions 24b and 25b of the side rails 24 and 25 are fastened with the bolt 28, the bolt head does not protrude from the surface of the flat portion 26a. A nut is attached to the fixing portion 26b. The second end spacer 22 is configured similarly.

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

[0033] The busbar case assembly 1200 comprises a busbar 31, a harness, a gas exhaust duct 234, a plurality of covers 34, and a busbar case 35. The busbar case assembly 1200 has functions such as electrical connection between the terminals of the battery cells 701 and to the controller, monitoring of voltage and temperature, and gas exhaust.

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

[0035] The busbar case 35 is made of insulating resin. The busbar case 35 has a series of frames 35a arranged on both sides in the width direction along the stacking direction of the battery cells 701, and the intercell busbars 31a, negative electrode busbars 31b, and positive electrode busbars 31c are housed within the frames, respectively. A base plate portion 35b is formed on the side of the busbar case 35 facing the battery cell group 800, and is placed on the battery cell group 800.

[0036] The gas exhaust duct 234, as described in the claim, is made of resin and extends over the battery cell group 800 with a length in the X direction, facing the battery cell group 800. The gas exhaust duct 234 is fixed to the female threads of the second end spacer 22 and the first end spacer 23 with screws located at both ends in the X direction. The multiple covers 34 have the function of insulating and protecting the components of the busbar case assembly 1200 and are arranged to cover the busbar 31 and harness. Each cover 34 is fitted and fixed to the busbar case 35.

[0037] The gas exhaust duct 234 extends in the X direction and has a tunnel-like shape with its side facing the battery cell group 800 open along the X direction. As shown in Figure 6, the gas exhaust duct 234 and the base plate portion 35b are combined such that the open portion of the gas exhaust duct 234 is covered by the busbar case 35 (base plate portion 35b) on the plane of the battery cell group 800. That is, the flange portions (234f, 234g) on ​​the periphery of the gas exhaust duct 234 are supported by the periphery of the base plate portion 35b, and as a result, a tunnel-like, isolated space oriented in the X direction is formed. This is the gas flow path 780 (Figures 9 and 10). The base plate portion 35b, which is the surface facing the battery cell group 800, is an example of the bottom surface portion described in the claim.

[0038] The gas discharge duct 234 isolates and collects the gas discharged from the gas discharge valve 706 of at least one battery cell 701 of the battery cell group 800 in the center in the width direction (Y direction), guides it in the X direction within the gas flow path 780, and discharges it from the gas outlet 233.

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

[0040] To improve the airtightness of the gas passage 780, the gas exhaust duct 234 is pressed against and connected to the battery cell group 800 via the base plate portion 35b along the X direction. As a result, the first sealing member 245 (Figure 6) at the joint (joint surface) between the gas exhaust duct 234 and the base plate portion 35b is compressed, improving the sealing performance and suppressing gas leakage from the exhaust gas passage 780. Furthermore, the second sealing member 246 (Figure 6) between the base plate portion 35b and the battery cell group 800 is strongly compressed, preventing the gas discharged from the gas exhaust valve 706 from flowing outside the exhaust gas passage 780.

[0041] The rigidity of the gas passage 780 is increased when the gas exhaust duct 234 and the base plate portion 35b are pressed against the battery cell group 800. Even when the battery pack 11 is subjected to physical stress such as vibrations and shaking during vehicle operation, deformation such as displacement and rattling of the exhaust gas passage 780 is suppressed, and in combination with the sealing member, the sealing performance against gas leakage is improved. As one form of pressing, the gas exhaust duct 234 may be engaged with the battery cell group 800 via the base plate portion 35b. One form of the structure for engagement is as follows.

[0042] The spacers 721 and end spacers 22 and 23 of the battery cell group 800 each have a pair of claws (hooks) 342 as engaging parts (Figure 10). As shown in Figure 8, the gas discharge duct 234 has hooks 343 and 343a as engaging parts on its X-direction side surface 234t. Multiple hooks 343 are arranged on the side surface 234t of the gas discharge duct 234 at a constant pitch in the X direction so that they face the claws 342 of each of the multiple spacers 721, 22, and 23. The hooks 343a at both ends of the side surface 234t in the X direction are for the end spacers 22 and 23, respectively.

[0043] When the gas exhaust duct 234 is pressed against the battery cell group 800, the pair of claws 342 of the spacers 721, 22, and 23 engage with the hooks 343 and 343a of the gas exhaust duct 234. As a result, the gas exhaust duct 234 is supported by the base plate portion 35b and is firmly pressed against and fixed to the battery cell group 800 along the X direction via the base plate portion 35b.

[0044] As shown in Figure 10, the claw portion 342 protrudes perpendicularly from the Z-direction end faces of the spacers 721, 22, and 23. A pair of claw portions 342 exist symmetrically at the Y-direction center of the spacer. Claw portions 342 may be provided on all spacers 721 and / or end spacers 22 and 23. The gas exhaust duct 234 has multiple hooks 343 corresponding to the number and position of the claw portions of the spacers. As shown in Figure 8, each of the multiple hooks 343 curves from the Z-direction lower end of the gas exhaust duct 234 and protrudes toward the battery cell group 800. The hook 343 consists of a substantially U-shaped arm 343d. As shown in Figures 8 and 10, the claw portion 342 fits into the inner recess 343c of the arm and engages with the lower end 343b of the arm.

[0045] Multiple fixing means, each consisting of a claw portion 342 (engaging element) and a hook 343 (engaged element), are evenly distributed along the X direction on both sides of the battery cell group 800 in the Y direction. As a result, the gas exhaust duct 234 and the base plate portion 35b are pressed against the battery cell group 800, and therefore the exhaust gas passage 780 can be constructed with high rigidity in the X direction. Note that although the claw portion is referred to as the engaging element and the hook as the engaged element, these terms may be reversed.

[0046] The spacers on which the claw portion 342 is provided may be only some of the spacers. When the claw portion is provided on some of the spacers, the spacers on which the claw portion should be provided are selected such that the position and number of claw portions on both sides of the Y direction are symmetrical in the X direction of the battery cell group 800. By providing the claw portion 342 on the end spacers 22 and 23, the gas flow path 780 can withstand the high pressure caused by turbulence at both ends in the X direction.

[0047] The base plate portion 35b is provided with multiple openings 35c facing the gas discharge valves 706 of each of the multiple battery cells 701, so as not to interfere with the gas discharge valves 706 (Figures 6, 7, 9, 10). The openings 35c are formed to be slightly larger than the area of ​​the gas discharge valves 706 so as not to obstruct the outflow of gas from the gas discharge valves 706 to the gas flow path 780 (Figures 3, 9).

[0048] The base plate portion 35b of the gas exhaust duct 234 is provided with flanges 243f bent at a right angle along the X direction at both ends in the Y direction, and flanges 243g bent at a right angle along the Y direction at both ends in the X direction of the base plate portion 35b of the gas exhaust duct 234 (Figures 6, 8, 10). The first sealing member 245 is compressed and clamped and fixed at the joint surface between these flanges 234f, 234g and the base plate portion 35b (Figures 6, 10). The first sealing member 254 extends along the gas exhaust duct 234 in the X direction. Therefore, leakage of gas from the joint surface around the entire circumference of the gas flow path 780 is suppressed.

[0049] As shown in Figure 9, the base plate portion 35b is provided with a recess 344 on the battery cell group 800 (battery cell 701) side into which the second sealing member 246 (Figure 6) is fitted. When the base plate portion 35b is pressed against the battery cell group 800, the second sealing member 246 is compressed within the recess 344 and is sandwiched and fixed between the base plate portion 35b and the battery cell group 800. Therefore, the second sealing member 246 around the gas discharge valve 706 seals the gas discharge valve 706 from all but the gas passage 780.

[0050] The second sealing member 246 is interposed between the base plate portion 35b and the battery cell group 800, and therefore has an opening 246c (Figure 6) that does not interfere with the gas discharge valve 706, similar to the opening 35c of the base plate portion 35b. In order to align the two openings 35c and 246c, the second sealing member 246 is fitted into the recess 344 on the battery cell group 800 side of the base plate portion 35b. The first sealing member 245 and the second sealing member guide the gas discharged from the gas discharge valve 706 along the gas flow path 780 without leakage from the gas flow path 780.

[0051] The sealing members 245 and 246 described above may be, for example, compressible resin elastic materials such as urethane, polypropylene, EPDM, or rubber. The sealing members are fixed to the opposing surfaces by adhesive using double-sided tape or other adhesives. Because the sealing members are compressed and fixed to the opposing surfaces, the rigidity of the sealing portion can be improved. As a result of the improved rigidity of the gas flow path due to the rigidity of the sealing portion and the engagement between the claw portion 342 and the hook 343 described above, even if stress is applied to the battery pack due to vehicle motion or the like, displacement and rattling of the gas flow path are suppressed, and sealing performance is maintained.

[0052] As shown in Figure 10, in the width direction (Y direction) of the gas exhaust duct 234, the position where the first sealing member 245 is sandwiched between the gas exhaust duct 234 and the base plate portion 35b is closer to the center of the battery cell 701 in the width direction (Y direction) than the position where the claw portion 342 engages with the lower end 343b (Figure 8) of the hook 343. Furthermore, in the height direction (Z direction) of the gas exhaust duct 234, the position where the claw portion 342 engages with the lower end 343b (Figure 8) of the hook 343 is closer to the battery cell 701 than the position where the first sealing member 245 is sandwiched between the gas exhaust duct 234 and the base plate portion 35b. As a result, even if multiple claw portions 342 must be engaged with each hook 343 in order to fit the claw portion 342 onto the hook 343 after the position of the first sealing member 245 has been determined, the battery pack 11 can accurately perform each engagement without misalignment.

[0053] For the first sealing member 245 and the second sealing member 246, a urethane foam (PORON®) with a fine and uniform cell structure is preferred. This is because it has very low compression residual strain, excellent sealing properties, and excellent energy absorption properties. Even if stress is applied to the sealing portion, the high rigidity of the sealing portion means that there is little risk of the sealing performance being impaired.

[0054] According to the embodiments described above, the following battery pack is provided. The first battery pack 11 comprises a battery cell group 800 in which a plurality of battery cells 701 are arranged in a row, a duct 234 extending along the battery cell group 800, and a bottom portion 35b of the duct 234 facing the battery cell group 800 and, in combination with the duct 234, forming a flow path 780 for guiding gas discharged from at least one of the plurality of battery cells 701, wherein the duct 234 is pressed against the battery cell group 800 via the bottom portion 35b.

[0055] According to the first battery pack, a first sealing member 245 is provided at the joint surface between the duct 234 and the bottom surface 35b, and the bottom surface 35b is arranged in the battery cell group 800 via a second sealing member 246. Therefore, the rigidity of the sealing surface related to the gas-guiding flow path 780 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, thereby providing a battery pack that is free from the risk of gas leakage from the battery cells.

[0056] The second battery pack is characterized in that, in the first battery pack, the bottom surface 35b is the surface of the busbar case 35 facing the battery cell group 800. According to the second battery pack, by utilizing the busbar case 35, it is possible to provide a battery pack that does not pose a 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 is engaged toward the battery cell group 800 via the bottom portion 35b. According to the third battery pack, the rigidity of the sealing portion of the flow path 780 can be further improved because the duct 234 is engaged toward the battery cell group 800 while being supported by the bottom portion 35b.

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

[0059] The fifth battery pack is characterized in that, in the fourth battery pack, engaging portions 342 are provided on all spacers 721 positioned between multiple battery cells of the battery cell group 800. According to the fifth battery pack, the rigidity and sealing performance 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 is provided with end spacers 22, 23 at the ends in the direction in which the plurality of battery cells 701 are stacked, and the end spacers have engaging portions. According to the sixth battery pack, the sealing performance can be improved against gas turbulence that may occur at the longitudinal ends of the flow path 780.

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

[0062] The eighth battery pack is characterized in that, in the first battery pack, each of the multiple battery cells 701 of the battery cell group 800 is equipped with a gas discharge valve 706, the bottom portion 35b and the second sealing member 246 are equipped with openings 35c and 246c (Figure 6) that do not obstruct the outflow of gas from the gas discharge valve 706, and the second sealing member 246 is compressed and sandwiched between the base plate portion 35b and the battery cell 701 in portions other than the openings. According to the eighth battery pack, the sealing performance of the flow path 780 can be improved while not obstructing the outflow of gas from the openings to the flow path 780. The openings 35c and 246c are sized to be larger than the area of ​​the gas discharge valve 706, or, if the openings are narrowed for reasons such as increasing the rigidity of the structure, they are sized to be at least 80% or larger.

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

[0064] Therefore, even if, after determining the position of the first sealing member 245, multiple claw portions 342 must be engaged with each hook 343 in order to fit the claw portion 342 onto the hook 343, the battery pack 11 can perform each engagement accurately and without misalignment.

[0065] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the technical concept of the present invention as described in the claims. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add a configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with other configurations. [Explanation of Symbols]

[0066] 11: Battery pack, 35b: Bottom surface, 234: Duct, 245: First sealing member, 246: Second sealing member, 701: Battery cell, 780: Flow path, 800: Battery cell group

Claims

1. A battery pack comprising a group of battery cells arranged in a row, A duct extending along the aforementioned battery cell group, The bottom surface of the duct faces the group of battery cells and, in combination with the duct, forms a flow path for guiding gas discharged from at least one of the plurality of battery cells, Equipped with, The duct is pressed against the battery cell group via the bottom portion. Each of the multiple battery cells in the aforementioned battery cell group is equipped with a gas discharge valve. The bottom surface is the surface of the bus case facing the battery cell group. A first sealing member is provided at the joint surface between the duct and the bottom surface. The duct and the bottom portion form the joint surface at their respective peripheral edges. The first sealing member is compressed and sandwiched between the duct and the bottom surface, The bottom portion is arranged in the battery cell group via a second sealing member. The bottom portion and the second sealing member are each provided with an opening that does not obstruct the outflow of gas from the gas discharge valve. The second sealing member is compressed and sandwiched between the bottom surface and the battery cell in portions other than the opening. The bottom portion has a recess on the battery cell group side into which the second sealing member is fitted. Battery pack.

2. The duct is engaged with the battery cell group via the bottom portion. The battery pack according to claim 1.

3. Each of the plurality of battery cells in the aforementioned battery cell group is stacked on top of each other with spacers in between. The spacer is provided with an engaging portion that protrudes toward the duct, The engagement portion engages with the duct. The battery pack according to claim 2.

4. The engaging portion is provided on all of the spacers that are arranged between the plurality of battery cells of the battery cell group. The battery pack according to claim 3.

5. The battery cell group is provided with end spacers at the ends in the direction in which the plurality of battery cells are stacked, and the end spacers have the engagement portion. The battery pack according to claim 4.

6. In the width direction of the duct, the position in which the first sealing member is sandwiched between the duct and the bottom surface is closer to the center of the battery cell than the position in which the engaging portion engages with the duct. The battery pack according to claim 1.

7. In the height direction of the duct, the position where the engaging portion engages with the duct is closer to the battery cell than the position where the first sealing member is sandwiched between the duct and the bottom surface. The battery pack according to claim 1.

Images