JP2023063820A - Battery unit gas discharge structure - Google Patents

Abstract

To lower the temperature of exhaust gas emitted from battery cells 2.SOLUTION: An exhaust gas duct 4 is provided through which exhaust gas emitted from battery cells 2 of a battery module flows and is discharged to the outside. The exhaust gas duct 4 includes an exhaust gas inlet 9, a tapered passage 14 through which the exhaust gas that has flowed in from the inlet 9 passes, and a shielding wall 15 that interrupts the forward movement of the exhaust gas that has passed through the tapered passage 14 and deflects the exhaust gas laterally, thereby generating a swirling flow in the exhaust gas at an adjacent portion across the passage wall of the tapered passage 14, and an exhaust gas discharge port 8 is opened so as to face the part where the exhaust gas vortex is generated.SELECTED DRAWING: Figure 3

Description

The present invention relates to a gas discharge structure for a battery unit having a plurality of battery cells arranged side by side.

The battery cell has a gas discharge valve that opens when gas is generated inside due to abnormal heat generation and the internal pressure rises. The battery unit is provided with an exhaust gas duct for leading the exhaust gas to the outside so that the exhaust gas emitted from the battery cells does not damage the surrounding battery cells. When the temperature of the exhaust gas discharged from the exhaust gas duct is high, there is concern that the exhaust gas may damage equipment around the battery unit. Therefore, it is desirable to allow the temperature of the exhaust gas to drop while passing through the exhaust gas duct.

Patent Literature 1 describes that a plurality of flat plate portions are provided in an exhaust gas duct to change the flow direction of exhaust gas in a zigzag pattern multiple times. The method is to lengthen the stroke of the exhaust gas to promote heat exchange between the exhaust gas and the exhaust gas duct, thereby lowering the temperature of the exhaust gas.

International Publication No. WO2016/136193

In the method of lengthening the stroke of the exhaust gas passage, it is necessary to provide a large number of flat plate portions in the exhaust gas duct in order to lower the temperature of the exhaust gas. This complicates the duct structure and increases the product cost.

Accordingly, an object of the present invention is to reduce the temperature of exhaust gas emitted from a battery cell without complicating the exhaust gas duct structure.

In order to solve the above problems, the present invention positively utilizes turbulent heat transfer to lower the exhaust gas temperature.

In the battery unit gas discharge structure disclosed herein, a battery module having a plurality of battery cells arranged side by side is provided with an exhaust gas duct for introducing exhaust gas emitted from the battery cells and discharging it to the outside,
The exhaust gas duct includes an inlet for the exhaust gas, a tapered passage in which the width of the passage through which the exhaust gas that has flowed in from the inlet becomes narrower as it goes forward, and an advance of the exhaust gas that has passed through the tapered passage is interrupted. a shielding wall that deflects the exhaust gas laterally to generate a swirl in the exhaust gas at an adjacent portion separated from the passage wall of the tapered passage, and the exhaust gas flows out to the outside so as to face the portion that causes the swirl of the exhaust gas. It is characterized in that a discharge port for letting out is opened.

According to this, the flow velocity of the exhaust gas increases as it passes through the tapered passage and collides with the shielding wall in that state, causing the flow direction to deviate laterally, thereby generating a strong exhaust gas swirl. Therefore, the temperature gradient of the exhaust gas increases in the vicinity of the shield wall where the exhaust gas collides, and new exhaust gas is caught in the swirling flow generated in the portion adjacent to the tapered passage, thereby increasing the temperature gradient of the exhaust gas in the vicinity of the passage wall. Therefore, the heat transfer coefficient from the exhaust gas to the shield wall and passage wall increases. In addition, the generation of the vortex increases the time during which the exhaust gas is flowing inside the exhaust gas duct. As described above, the heat transfer coefficient from the exhaust gas to the shield wall or the passage wall increases, and the flowing time of the exhaust gas increases, resulting in a large decrease in the temperature of the exhaust gas up to the exhaust port of the exhaust gas duct.

In one embodiment, the exhaust gas duct includes the inlet and the outlet for each battery cell,
For each battery cell, a pair of tapered passages extending in the same direction along the line are arranged symmetrically with respect to the line on both sides of the line connecting the inlet and the outlet of the battery cell,
The shielding wall widens in front of the pair of tapered passages so as to block the advance of the exhaust gas that has passed through each tapered passage.

According to this, the exhaust gases passing through the tapered passages on both sides of the line connecting the inflow port and the exhaust port are blocked by the shield walls, and collide with each other as they flow along the shield walls. As a result, two strong vortices are generated symmetrically on both sides of the line between the tapering passages. Therefore, the heat transfer from the exhaust gas to both tapered passage walls is facilitated, so that the temperature of the exhaust gas is greatly reduced.

In one embodiment, each of the plurality of battery cells has a rectangular shape in a plan view, is arranged side by side in the short side direction of the rectangular shape, and has internally generated gas at the center of each upper surface in the long side direction. A gas exhaust valve is provided to release
The inlet of the exhaust gas duct opens so as to correspond to the gas discharge valve at the center of the battery cell in the long side direction, and the outlet of the exhaust gas duct is the end side of the battery cell in the long side direction. open to accommodate
Each of the tapered passages on both sides of the line connecting the inflow port and the discharge port is slanted away from the line as the passage wall on the side closer to the line goes forward, and is aligned in the direction in which the battery cells are arranged side by side. The aisle width is tapered.

According to this, the gas emitted from each battery cell can be cooled by the exhaust gas duct and discharged from the inlet corresponding to each gas discharge valve. Thus, in this embodiment, in the tapered passages on both sides of the line connecting the inlet and the outlet, the passage walls on the side closer to the line are inclined, and the width of the passage in the direction in which the battery cells are arranged is tapered. there is Therefore, the inclined passage wall serves as a guide to promote the inflow of the exhaust gas into the tapered passage, and contributes to the formation of a vortex of the exhaust gas that is blocked by the shield wall and reversed. Therefore, the temperature drop of the exhaust gas up to the exhaust port of the exhaust gas duct increases.

In one embodiment, the tapered passage provided for one of the adjacent battery cells and positioned closer to the other battery cell, and the tapered passage provided for the other battery cell and closer to the one battery cell The tapered passages are arranged at intervals in the direction in which the battery cells are arranged side by side, and a gap is provided between the tip of the passage wall on the far side from the line of each of the tapered passages and the shield wall. It is

The fact that the tapered passage provided in one of the adjacent battery cells and the tapered passage provided in the other of the adjacent battery cells are spaced apart in the direction in which the battery cells are arranged side by side means that both of the tapered passages are separated from the line. This means that the passage walls on the far side are separately provided without sharing the passage walls on the far side. Therefore, the amount of heat transferred from the exhaust gas to the passage wall is increased. Since a gap is formed between the tip of the passage wall on the far side from the line and the shielding wall, the exhaust gas flowing between the tapered passages also passes through the tapered passage through the gap. join the exhaust gas. Therefore, the exhaust gas flowing between the two tapered passages is also caught in the vortex and is deprived of heat by the shield wall and the passage wall, which is advantageous for lowering the temperature of the exhaust gas exiting the exhaust port.

In one embodiment, the tip of the tapered passage wall farther from the line protrudes forward than the tip of the passage wall closer to the line. According to this, a large amount of the exhaust gas that has passed through the tapered passage flows into the portion adjacent to the tapered passage on the line side, which is advantageous for enhancing the vortex formation in the adjacent portion.

According to the present invention, the exhaust gas is passed through the tapered passage, the advance of the exhaust gas that has passed through the passage is blocked by the shielding wall, and the exhaust gas is deflected laterally, so that the exhaust gas passes through the adjacent portion separated by the passage wall of the tapered passage. Since the vortex is generated, the heat transfer coefficient from the exhaust gas to the shield wall or the passage wall is increased, and the temperature of the exhaust gas flowing into the exhaust gas duct and reaching the discharge port is increased.

The perspective view of a battery unit. The perspective view of a battery cell. The top view which shows the internal structure of an exhaust gas duct. FIG. 6 is a streamline diagram of exhaust gas in an exhaust gas duct (a streamline diagram along line BB in FIG. 6). A detailed streamline diagram of the exhaust gas in a part of the exhaust gas duct. FIG. 5 is a streamline diagram along line A-A in FIG. The top view which shows the internal structure of the waste gas duct of a comparative example. Graph diagram showing non-stationary calculation results of outlet gas temperatures in Examples, Comparative Examples, and without ribs. FIG. 5 is a graph showing unsteady calculation results of the heat transfer coefficient from the exhaust gas to the rib in each of the examples and the comparative examples. FIG. 5 is a graph showing unsteady calculation results of the amount of heat transferred from the exhaust gas to the rib in each of the examples and the comparative examples. FIG. 4 is a plan view similar to FIG. 3, according to another embodiment;

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on drawing. The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications or uses.

<Battery unit>
A battery unit 1 shown in FIG. 1 is for a vehicle and includes a battery module 3 in which a plurality of chargeable/dischargeable battery cells 2 are arranged side by side, and an exhaust gas duct 4 is provided on the battery module 3. .

As shown in FIG. 2, the battery cell 2 has a rectangular parallelepiped shape in which the opposing side surfaces are wider than the other side surfaces, top surface and bottom surface. A gas discharge valve 5 for discharging gas generated inside the battery cell 2 is provided in the center of the rectangular upper surface of the battery cell 2 in plan view, and positive and negative electrode terminals 6 and 7 are provided at both ends of the upper surface. is provided.

As shown in FIG. 1, the plurality of battery cells 2 are arranged side by side so as to overlap each other in the short side direction of the upper surface, that is, so that their wide side surfaces face each other. Although not shown, coolant passage members are interposed between adjacent battery cells 3 .

<Structure of Exhaust Gas Duct>
The exhaust gas duct 4 is a square duct that discharges the exhaust gas discharged from the gas discharge valve 5 of the battery cell 2 to the outside. The exhaust gas duct 4 extends above the battery modules 3 in the direction in which the battery cells 2 are arranged side by side (hereinafter referred to as the "cell parallel direction"). A plurality of discharge ports 8 are opened at intervals in the cell arrangement direction at both side edges of the upper surface of the exhaust gas duct 4 .

As shown in FIG. 3 , an exhaust gas inlet 9 is opened in the bottom surface of the central portion in the duct width direction of one end of the exhaust gas duct 4 . Inside the exhaust gas duct 4, a tapered passage 14 and a vortex generating portion 16 are formed by a plurality of horizontal ribs 11 extending in the duct width direction and a plurality of inclined ribs 12 and 13 inclined with respect to the duct width direction. The transverse ribs 11 and the oblique ribs 12, 13 constitute the passage walls of the tapered passage 14. As shown in FIG. A specific description will be given below.

The exhaust gas inlet 9 is opened at a position corresponding to the gas discharge valve 5 of the battery cell 2 at the end of the module, which can be a trigger cell for thermal runaway of the battery module 3 due to a vehicle collision or the like. The exhaust gas outlets 8 are opened one by one at positions corresponding to both ends in the long-side direction of the upper surface of the battery cells 2 other than the trigger cell.

The horizontal rib 11 and the inclined ribs 12 and 13 are plate-shaped ribs rising from the bottom surface of the exhaust gas duct 4 . The slanted rib 12 and the slanted rib 13 are slanted in opposite directions. Inside the exhaust gas duct 4 , four horizontal ribs 11 , two inclined ribs 12 and two inclined ribs 13 are provided corresponding to each of the other battery cells 2 .

Specifically, two horizontal ribs 11 and two slanted ribs 12 and 13 are provided inside the exhaust gas duct 4 at a portion corresponding to one end of the upper surface of each battery cell 2 (near one end in the width direction of the duct). are placed. The two lateral ribs 11 are arranged so as to face each other in the short side direction (cell parallel direction) of the upper surface of the battery cell 2 with the outlet 8 interposed therebetween. Between the two lateral ribs 11, an inclined rib 12 inclined so as to approach one lateral rib 11 closer to the inflow port 9 toward the end in the duct width direction, and A slanted rib 13 is arranged so as to approach the other lateral rib 11 far from the inlet 9 .

Two horizontal ribs 11 and two slanted ribs 12 and 13 are arranged inside the exhaust gas duct 4 at a portion corresponding to the other end of the upper surface of each battery cell 2 (closer to the other end in the width direction of the duct). It is As in the case near one end, the two lateral ribs 11 are arranged so as to face each other in the short-side direction (cell parallel direction) of the upper surface of the battery cell 2 with the outlet 8 interposed therebetween. Between the two horizontal ribs 11, an inclined rib 13 inclined so as to approach one of the horizontal ribs 11 closer to the inlet 9 as it goes toward the end in the duct width direction, and A slanted rib 12 is arranged so as to approach the other lateral rib 11 far from the inlet 9 .

Since the slanted rib 12 is slanted so as to approach one of the horizontal ribs 11 as it goes to the end side in the duct width direction, the width of the passage in the direction in which the cells are arranged side by side is reduced by the slanted rib 11 and the slanted rib 12 in the duct width direction. A tapered passage 14 is formed which is gradually narrowed toward the end of the tube. Similarly, the inclined rib 13 is inclined so as to approach the other horizontal rib 11 as it goes toward the end in the duct width direction. A tapered passage 14 is formed which is gradually narrowed toward the end side in the duct width direction.

Side walls of the exhaust gas duct 4 stand in front of the one tapered passage 14 close to the inlet 9 and the other tapered passage 14 far from the inlet 9 . This side wall constitutes a shielding wall 15 that widens so as to block the forward movement of the exhaust gas that has passed through each tapered passage 14 . Exhaust gas that has passed through the tapered passage 14 is blocked from advancing by the shielding wall 15 and deviates laterally. Thus, the slanted ribs 12, 13 of the tapered passage 14 and the shielding wall 15 form a vortex generator 16, which will be described in detail later.

In this example, a tapered passage 14 provided for one of the adjacent battery cells 2 and positioned closer to the other battery cell 2, and a tapered passage 14 provided for the other battery cell 2 and positioned for the one battery cell 2 The tapered passage 14 positioned closer is spaced apart in the cell arrangement direction. That is, the tapered passages 14 do not share the horizontal ribs 11, but are formed by using separate horizontal ribs 11 to form the tapered passages. A gap is provided between the end of the inclined rib 12 on the center side in the duct width direction and the end of the inclined rib 13 on the center side in the duct width direction.

When the line L connecting the two outlets 8 facing each other in the duct width direction is used as a reference, the one tapered passage 14 and the other tapered passage 14 are arranged symmetrically with respect to the reference line L. extending in the same direction along the Also, in the pair of tapered passages 14 provided on both sides of the reference line L, the slanted ribs 12 and 13, which are passage walls on the side closer to each reference line L, are inclined so as to move away from the line L as it goes forward in the passage. As a result, it can be said that the passage width in the direction in which the cells are arranged is tapered.

When the center line extending in the longitudinal direction of the exhaust gas duct 4 is used as a reference, the tapered passage 14 on one side in the width direction of the duct and the tapered passage 14 on the opposite side are arranged symmetrically with respect to the line.

The discharge port 8 opens at a position facing the vortex generator 16 laterally displaced from the front position of the tapered passage 14 .

The lateral rib 11 and the slanted rib 12 or 13 forming each tapered passage 14 are such that the tip of the lateral rib 11 constituting the passage wall far from the reference line L, which faces the shielding wall 15, forms the passage wall closer to the reference line L. It protrudes forward beyond the tip of the inclined rib 12 or 13 that constitutes it. A gap 17 is provided between the tip of each lateral rib 11 and the shielding wall 15, through which the exhaust gas can pass.

<Flow of Exhaust Gas in Exhaust Gas Duct>
Next, the flow of exhaust gas in the exhaust gas duct 4 will be described with reference to the streamline analysis results of the exhaust gas in the exhaust gas duct 4 shown in FIGS.

As shown in FIG. 4, between one end wall 10 in the longitudinal direction of the duct where the inlet 9 of the exhaust gas duct 4 exists and the two lateral ribs 11 closest to the inlet 9, exhaust gas flows as follows. A vortex is generated. Gas flows in from the inlet 9, is blocked by the wall 10 at one end of the duct, flows toward both side walls (shielding walls 15) of the duct, and flows from each of the side walls toward the center in the duct width direction along the lateral ribs 11 near the ends. producing a flow. Then, this gas flow collides with the gas flow that advances directly from the inlet 9 toward between the two lateral ribs 11 near the end, resulting in a gap between the inlet 9 and the two lateral ribs 12 near the end. A vortex 18 is generated in the

Exhaust gas that escapes between the two lateral ribs 12 near the ends enters two tapered passages 14 on the battery cell, as shown in FIG. The two flows of the exhaust gas, which have passed through the two tapered passages 14 and have increased in flow velocity, are blocked by the shielding wall 15 from advancing forward, become opposing flows, collide with each other, and flow between the two tapered passages 14, i.e., , a vortex 19 is generated in the vortex generator 16 .

As described above, the vortex flow of the exhaust gas is generated in the vortex generator 16, and as shown in FIG.

As described above, the exhaust gas flowing in from the inlet 9 generates the vortex 18 between the inlet 9 and the lateral rib 11 near the end, and further, after passing through the tapered passage 14, the vortex 19 is generated in the vortex generator 16. . Therefore, the exhaust gas flows for a longer period of time inside the exhaust gas duct 4, so that the heat transfer from the exhaust gas to the duct wall and the ribs 11 to 13 constituting the exhaust gas duct 4 progresses, and the temperature of the exhaust gas decreases.

Further, the occurrence of vortex flow in the exhaust gas means that the turbulence of the exhaust gas flow is increased. Therefore, the temperature gradient of the exhaust gas increases in the vicinity of the main body wall surface of the exhaust gas duct 4 and in the vicinity of the wall surfaces of the ribs 11 to 13 . That is, the heat transfer coefficient from the exhaust gas to the wall of the duct body and the ribs 11 to 13 is increased, and the temperature of the exhaust gas is efficiently lowered.

Here, in the swirl generation section 16, the flow velocity of the exhaust gas is increased by the tapered passage 14, and in this state, the flow of the exhaust gas collides with the shielding wall 15 and is deflected laterally, so that a strong swirl is likely to be generated. In addition, since the tip of the lateral rib 11 farther from the reference line L is closer to the shielding wall 15 than the inclined ribs 12 and 13 closer to the reference line L, the exhaust gas passing through the tapered passage 14 flows toward the reference line L, that is, toward the reference line L. , easily flows toward the vortex generator 16 . This works advantageously to strengthen the vortex of the exhaust gas in the vortex generator 16 . Furthermore, since the gap 17 is provided between the tip of the horizontal rib 11 and the shielding wall 16, the exhaust gas flowing from between the horizontal ribs 11 facing in the cell arrangement direction toward the shielding wall 15 also passes through the gap 17 and tapers off. Joins the exhaust gas that has passed through the passage 14 . This also works to strengthen the vortex of the exhaust gas in the vortex generator 16 .

<Performance evaluation of exhaust gas duct>
A ribbed exhaust gas duct 4 (hereinafter referred to as “comparative example”) and a ribless exhaust gas duct (hereinafter referred to as “ribless”) according to the comparative example shown in FIG. 7 were manufactured. The performance of the comparative example, the rib-free exhaust gas duct 4 according to the above-described embodiment (hereinafter referred to as "example") was examined.

As shown in FIG. 7, the comparative example is an exhaust gas duct in which a plurality of vertical ribs 21 extending in the duct longitudinal direction are arranged at intervals in the duct width direction and longitudinal direction on the duct body similar to the example. The non-ribbed duct is formed only by a duct body similar to that of the embodiment, and has no ribs. The shape and size of the duct body, and the size and arrangement of each of the exhaust gas inlet 9 and outlet 8 are the same in the example, the comparative example, and without ribs. The number of ribs and the total surface area of the ribs in the Examples and Comparative Examples are the same.

The outlet gas temperature, that is, the temperature of the exhaust gas discharged from the outlet 8 closest to the inlet 9, was determined by unsteady analysis for the above examples, comparative examples, and without ribs. The results are shown in FIG.

The comparative example with longitudinal ribs has a lower outlet gas temperature than without ribs, but the outlet gas temperature at peak time temporarily exceeds the ignition point of 300° C. of the electrolyte contained in the gas released from the battery cell. has exceeded On the other hand, in the example, the peak temperature is about 150° C. lower than in the comparative example, and it is expected that the safety will be significantly improved.

9 and 10 show the calculation results of the heat transfer coefficient α and the heat transfer amount Q from the exhaust gas to the ribs for the above examples and comparative examples. In the example, the heat transfer coefficient α is larger and the heat transfer amount Q is larger than in the comparative example. This is the effect of generating a strong swirl of the exhaust gas in the duct as described above.

<Another embodiment>
In the previous embodiment, the inlet 9 of the exhaust gas duct 4 was provided only at the location corresponding to the trigger cell. As shown in FIG. 11, in the exhaust gas duct 4 according to this embodiment, an inlet 9 is provided for each battery cell 2 of the battery module.

That is, an inlet 9 is opened corresponding to the gas discharge valve 5 of each battery cell 2 on the bottom surface of the central portion of the exhaust gas duct 4 in the duct width direction. The outlet 8 is also provided for each battery cell 2 . Regarding the arrangement of the horizontal ribs 11 and the inclined ribs 12, 13, the arrangement of the horizontal ribs 11 and the inclined ribs 12, 13 provided corresponding to each battery cell 2 other than the trigger cell in the previous embodiment is basically the same. is the same as

However, at a portion of the exhaust gas duct 4 corresponding to the battery cell 2 at the end of the battery module, the wall 10 at one end of the duct is substituted for the lateral rib 11 . That is, a tapered passageway 14 is formed by the wall 10 at one end of the duct and the inclined ribs 12 and 13, respectively. In place of the horizontal ribs 11, flat plate ribs 22 and 23 rising from the bottom surface of the exhaust gas duct 4 are combined in a V-shape at portions corresponding to the second and third battery cells 2 from the end of the battery module. It is used for the V rib 24.

The base ends of the flat plate ribs 22 and 23 that constitute the V-rib 24 are joined to each other so as not to allow the exhaust gas to pass therethrough, and the distance between them increases toward the ends in the duct width direction. Inclined. The tips of the flat plate ribs 22 and 23 are in contact with the side wall of the duct, that is, the shielding wall 15, so that the inside of the V-rib 24 is prevented from entering the exhaust gas.

At a portion of the exhaust gas duct 4 where the V-rib 24 is provided, the tapered passage 14 is formed by the flat plate rib 22 and the slanted rib 12 that constitute the V-rib 24, and the tapered passage 14 is formed by the flat plate rib 23 and the slanted rib 13. .

Therefore, in this embodiment, a pair of tapered passages 14 are provided symmetrically with respect to the reference line L on both sides of the reference line L connecting the inlet 9 and the outlet 8 provided corresponding to each electrical facility cell 2. . A vortex generating portion 16 is formed between the inclined ribs 12 and 13 of each of the pair of tapered passages 14 .

In this embodiment, when the gas is discharged from the gas discharge valve 5 of each battery cell 2 , the exhaust gas flows into the exhaust gas duct 4 from the inlet 9 directly above the gas discharge valve 5 . Most of the gas passes through the tapered passages 14 arranged on both sides of the reference line L, is blocked by the shielding wall 15 and deviates to the reference line L side, and generates a gas vortex in the vortex generator 16. Therefore, as in the previous embodiment, the temperature of the gas is significantly lowered before it is discharged from the discharge port 8 .

Where the exhaust gas duct 4 is provided with the V rib 24, the exhaust gas cannot enter inside the V rib 24, so much exhaust gas flows into the tapered passage 14 whose passage wall is the V rib 24. - 特許庁Therefore, it is advantageous for strengthening the vortex in the vortex generator 16 . Moreover, since the flat plate ribs 22 and 23 forming the V-rib 24 are in contact with the shielding wall 15 , all of the exhaust gas that has passed through the tapered passage 14 is directed toward the vortex generating portion 16 . Therefore, a strong vortex can be generated in the vortex generator 16 .

Note that the V-ribs 24 can be used instead of the other lateral ribs 11, and the lateral ribs 11 can be used instead of the V-ribs 24.

1 Battery Unit 2 Battery Cell 3 Battery Module 4 Exhaust Gas Duct 5 Gas Discharge Valve 6 Electrode Terminal 7 Electrode Terminal 8 Discharge Port 9 Inlet 11 Horizontal Rib 12 Inclined Rib 13 Inclined Rib 14 Tapered Passage 15 Shielding Wall 16 Eddy Current Generating Section 17 Gap 19 swirl

Claims (5)

A gas discharge structure for a battery unit, in which a battery module having a plurality of battery cells arranged side by side is provided with an exhaust gas duct for allowing exhaust gas emitted from the battery cells to flow in and to be discharged to the outside,
The exhaust gas duct includes an inlet for the exhaust gas, a tapered passage in which the width of the passage through which the exhaust gas that has flowed in from the inlet becomes narrower as it goes forward, and an advance of the exhaust gas that has passed through the tapered passage is interrupted. a shielding wall that deflects the exhaust gas laterally to generate a swirl in the exhaust gas at an adjacent portion separated from the passage wall of the tapered passage, and the exhaust gas flows out to the outside so as to face the portion that causes the swirl of the exhaust gas. A gas discharge structure for a battery unit, characterized in that a discharge port for discharging gas is open. In claim 1,
The exhaust gas duct has the inlet and the outlet for each battery cell,
For each battery cell, a pair of tapered passages extending in the same direction along the line are arranged symmetrically with respect to the line on both sides of the line connecting the inlet and the outlet of the battery cell,
The gas discharge structure for a battery unit, wherein the shielding wall widens in front of the pair of tapered passages so as to block the forward movement of the exhaust gas that has passed through each of the tapered passages. In claim 2,
Each of the plurality of battery cells has a rectangular shape in a plan view, and is arranged side by side in a short side direction of the rectangular shape, and a gas discharge valve for discharging internally generated gas at the center of each upper surface in a long side direction. is provided,
The inlet of the exhaust gas duct opens so as to correspond to the gas discharge valve at the center of the battery cell in the long side direction, and the outlet of the exhaust gas duct is the end side of the battery cell in the long side direction. open to accommodate
Each of the tapered passages on both sides of the line connecting the inflow port and the discharge port is slanted away from the line as the passage wall on the side closer to the line goes forward, and is aligned in the direction in which the battery cells are arranged side by side. A gas discharge structure for a battery unit, characterized in that the passage width is tapered. In claim 3,
The tapered passage provided for one of the adjacent battery cells and positioned closer to the other battery cell, and the tapered passage provided for the other battery cell and positioned closer to the one battery cell. means that the tapered passages are arranged at intervals in the direction in which the battery cells are arranged side by side, and that a gap is provided between the tip of the passage wall on the far side from the line of each of the tapered passages and the shield wall. A gas discharge structure of a battery unit characterized by: In claim 4,
A gas discharge structure for a battery unit, wherein a tip of the tapered passage wall farther from the line protrudes forward than a tip of the passage wall closer to the line.

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