JP7632228B2 - Vehicle battery unit - Google Patents

Description

The present invention relates to a battery unit for a vehicle.

Battery cells in vehicle battery units tend to have higher energy density, which results in greater heat generation and temperature rise in the battery cells, making it necessary to cool the battery cells from the perspective of safety and maintaining their lifespan. An effective way to efficiently cool battery cells is to use a cooling method in which a refrigerant passage member that passes through a liquid refrigerant comes into direct contact with the battery cells.

Patent document 1 describes the placement of corrugated cooling tubes, through which a refrigerant flows, between battery cell rows, each of which consists of a number of cylindrical battery cells lined up, in such a way that they weave between the battery cells of adjacent rows. The same document also describes the placement of a thermally conductive medium between the cooling tubes and the battery cells.

JP 2010-528406 A

However, with the above cooling method, there is a concern that refrigerant leakage due to deterioration of refrigerant passage components such as cooling tubes over time or damage due to impact may cause the battery cells to short circuit (liquid junction). In other words, if refrigerant leaks from the refrigerant passage components and accumulates on the refrigerant passage components, the refrigerant may come into contact with the electrode terminals of the battery cells, causing a short circuit.

Therefore, the objective of the present invention is to prevent battery cells from shorting out even if liquid refrigerant leaks from the refrigerant passage members.

To solve the above problem, the present invention makes it possible to discharge leaking refrigerant from above the refrigerant passage member to below the refrigerant passage member.

The vehicle battery unit disclosed herein includes a plurality of battery cells and a refrigerant passage member having a refrigerant passage through which a liquid refrigerant for cooling the battery cells passes;
the refrigerant passage member is provided so that the refrigerant flows laterally along bottom surfaces or side surfaces of the plurality of battery cells,
The refrigerant passage member is characterized in that it includes a plurality of leaking refrigerant discharge pipe portions which vertically penetrate the refrigerant passage member and discharge refrigerant leaking from the refrigerant passage member from above the refrigerant passage member to below the refrigerant passage member.

This prevents leaking refrigerant from accumulating on the refrigerant passage members, preventing short circuits in the battery cells caused by leaking refrigerant.

In one embodiment, a case that accommodates the plurality of battery cells and the refrigerant passage member;
a plate that is disposed within the case with a gap between it and a bottom surface of the case and supports the plurality of battery cells;
the plate has a through hole that vertically penetrates the plate and guides the leaking refrigerant discharged downward from the leaking refrigerant discharge pipe portion to a bottom surface of the case,
An outlet for discharging the leaked refrigerant is opened in the bottom surface of the case.

With this, the leaked refrigerant discharged below the refrigerant passage member by the leaked refrigerant discharge pipe is guided through the through hole in the plate to the bottom of the case. Because there is a gap between the plate and the bottom of the case, this gap serves as a discharge path for the leaked refrigerant, and therefore the leaked refrigerant is smoothly discharged from the discharge port that opens into the bottom of the case without stagnation.

In one embodiment, each of the plurality of battery cells has a flat rectangular parallelepiped shape with upper and lower surfaces wider than the side surfaces, and is provided with an electrode terminal and a safety valve on one side surface of the battery cell,
The refrigerant passage member is placed on the plate, and the multiple battery cells are arranged side by side and placed on the plate via the refrigerant passage member so that the refrigerant flows laterally along the undersides of the multiple battery cells.

Therefore, each battery cell can be cooled from its underside by the refrigerant in the refrigerant passage member. Even if the refrigerant leaks from the refrigerant passage member, it can be discharged from above the refrigerant passage member to below by the leaking refrigerant discharge pipe section, so the refrigerant does not accumulate on the refrigerant passage member and short-circuiting of the battery cells is prevented.

In a configuration in which the multiple battery cells are arranged side by side and placed on the plate via the refrigerant passage member, the refrigerant passage member is preferably formed of a flexible silicone resin containing a thermally conductive filler, and its surface is covered with a gel that softens when it absorbs the refrigerant, forming a flat rectangular parallelepiped.

Therefore, when the refrigerant is not leaking, the refrigerant passage member has a flat upper surface, supporting multiple battery cells over a wide surface and cooling them from the underside. When refrigerant leaks from the refrigerant passage member, the parts of the refrigerant passage member that are wet with the refrigerant soften and collapse (depress) as the gel on the surface absorbs the refrigerant. This makes it easier for the leaked refrigerant to flow toward the leaked refrigerant discharge pipe, making it easier to discharge.

In one embodiment, each of the plurality of battery cells has a rectangular parallelepiped shape in which a pair of opposing side surfaces are wider than the other side surfaces, the top surface, and the bottom surface, and is provided with an electrode terminal and a safety valve on the top surface of the battery cell.
The plurality of battery cells are arranged side by side with the broad side surfaces facing each other,
The refrigerant passage member is arranged so that the refrigerant flows laterally along four side surfaces of each of the plurality of battery cells, and the leaking refrigerant discharge pipe portion is disposed around each of the plurality of battery cells.

Therefore, each battery cell can be cooled from its surroundings (sides) by the refrigerant in the refrigerant passage member. Even if refrigerant leaks from the refrigerant passage member, it can be discharged from above the refrigerant passage member to below by the leaking refrigerant discharge pipe section, so the refrigerant does not accumulate on the refrigerant passage member and short-circuiting of the battery cells is prevented.

In one embodiment, each of the plurality of battery cells has a rectangular parallelepiped shape in which a pair of opposing side surfaces are wider than the other side surfaces, the top surface, and the bottom surface, and is provided with an electrode terminal and a safety valve on the top surface of the battery cell.
The plurality of battery cells are arranged side by side with the broad side surfaces facing each other,
the refrigerant passage members extend on both sides of the plurality of juxtaposed battery cells in a direction in which the battery cells are arranged,
a thermally conductive material is provided between the refrigerant passage member and the battery cell and between adjacent battery cells, the thermally conductive material between the refrigerant passage member and the battery cell and the thermally conductive material between adjacent battery cells are continuous,
The height of the heat conductive material is greater than the height of the refrigerant passage member, and the upper end of the heat conductive material is greater than the upper end of the refrigerant passage member.

As a result, each battery cell can be cooled by the refrigerant in the refrigerant passage member through heat transfer from the thermally conductive material. Because thermally conductive material is provided between the battery cells instead of cooling passage members, this configuration is advantageous for shortening the length of the battery unit in the direction in which the battery cells are arranged side by side. Because the upper end of the thermally conductive material between the battery cells is higher than the upper end of the refrigerant passage member, it is possible to prevent leaking refrigerant from entering between the battery cells.

In one embodiment, the leaking refrigerant discharge pipe section located at the center of the arrangement direction of the plurality of battery cells has a larger inner diameter than the leaking refrigerant discharge pipe sections located at both ends.

The battery cells in the center of the battery cell arrangement are more likely to heat up than the battery cells at either end, so by increasing the inner diameter of the leaking refrigerant exhaust pipe in the center, the risk of short circuiting in the center is reduced, which is advantageous in improving safety.

According to the present invention, the refrigerant passage member is provided with multiple leaking refrigerant discharge pipe sections that discharge the refrigerant from above the refrigerant passage member to below the refrigerant passage member, which prevents leaking refrigerant from accumulating above the refrigerant passage member and is advantageous in preventing short circuits of battery cells due to leaking refrigerant.

FIG. 2 is a vertical cross-sectional view of the battery unit according to the first embodiment. FIG. 2 is a perspective view showing a refrigerant passage member, a support plate, and a case according to the first embodiment. 4 is a vertical cross-sectional view showing a leakage refrigerant discharge route when a refrigerant passage member of the battery unit according to the first embodiment is broken. FIG. FIG. 11 is a cross-sectional view of a battery unit according to a second embodiment. Cross-sectional view of line VV in Figure 4. FIG. 11 is a cross-sectional view of a battery unit according to a third embodiment. Cross-sectional view of line VV in Figure 6. FIG. 11 is a cross-sectional view of a battery unit according to a fourth embodiment. 9 is a cross-sectional view taken along line IX-IX in FIG. 8, with the thermal conductive material omitted.

The following describes the embodiments of the present invention with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

<Embodiment 1>
The vehicle battery unit 1 shown in Figure 1 comprises a case 2 housing a battery module 3, a refrigerant passage member 4, and a support plate 5. The battery module 3 comprises a plurality of chargeable and dischargeable battery cells 6. Each battery cell 6 has a flattened rectangular parallelepiped shape with the areas of its upper and lower faces larger than those of its side faces, i.e., a thin thickness in the vertical direction, and is provided with positive and negative electrode terminals 7 and a safety valve 8 on one side. The plurality of battery cells 6 are electrically connected in series by bus bars (not shown).

In the battery module 3 of this example, multiple battery cells 6 are stacked in the thickness direction in a flat stacked state, and multiple stacked battery cells 6 are arranged side by side, that is, arranged side by side in the horizontal direction. In the stacked cell of this example, two battery cells 6 are stacked, but the number of stacked battery cells is arbitrary. A thermally conductive material 9 is interposed between adjacent battery cells 6. The top and side surfaces of the battery module 3 (excluding the side surface having the electrode terminals 7 and safety valve 8) are also covered with the thermally conductive material 9. For example, a silicone resin mixed with a thermally conductive filler such as silica fine powder can be used as the thermally conductive material 9.

In the battery unit 1, the refrigerant passage member 4 is placed on the support plate 5, and the battery module 3 is placed on the support plate 5 via the refrigerant passage member 4.

As shown in Figure 2, the support plate 5 is made up of multiple plate materials 12 stretched across two parallel support bars 11 that extend horizontally. Between adjacent plate materials 12 of the support plate 5, there are open through holes 13 that pass vertically through the support plate 5. The support plate 5 supported by these support bars 11 is placed on the bottom surface of the rectangular case 2. As shown in Figure 1, there is a gap 14 between the support plate 5 and the bottom surface of the case 2 that corresponds to the height of the support bars 11.

As shown in FIG. 2, the refrigerant passage member 4 has a flat rectangular shape with a height smaller than its width, and extends in the direction in which the battery cells 6 are arranged side by side (hereinafter referred to as the "cell arrangement direction"). A refrigerant passage 15 is formed in the refrigerant passage member 4, through which a liquid refrigerant such as water passes. A refrigerant inlet 15a and an outlet 15b open at one end of the refrigerant passage member 4. The refrigerant passage 15 extends from the inlet 15a in the cell arrangement direction, turns back at the other end of the refrigerant passage member 4, and reaches the outlet 15b. An inlet 2a and an outlet 2b corresponding to the inlet 15a and the outlet 15b of the refrigerant passage member 4 open at one end of the case 2.

The refrigerant passage member 4 is provided with a plurality of leaking refrigerant discharge pipe sections 16a, 16b spaced apart in the direction of cell arrangement. The leaking refrigerant discharge pipe sections 16a, 16b penetrate the refrigerant passage member 4 from top to bottom, and discharge the refrigerant that has leaked from the refrigerant passage 15 onto the refrigerant passage member 4 below the refrigerant passage member 4. The leaking refrigerant discharge pipe sections 16a, 16b are tubular and extend vertically connecting the upper and lower walls of the refrigerant passage member 4, so that the refrigerant does not leak from the refrigerant passage 15 into the leaking refrigerant discharge pipe section 16. The leaking refrigerant discharge pipe section 16b located at the center in the direction of cell arrangement has a larger inner diameter than the leaking refrigerant discharge pipe sections 16a located at both ends in the direction of arrangement.

The holes of the leaking refrigerant discharge pipes 16a and 16b are located directly below the center between the positive and negative electrode terminals 7 of the battery cell 6. The holes of the leaking refrigerant discharge pipes 16a and 16b correspond vertically to the through holes 13 of the support plate 5, and the holes are smaller than the through holes 13. In other words, the through holes 13 of the support plate 5 are positioned so that the support plate 5 does not block the holes of the leaking refrigerant discharge pipes 16a and 16b. A leaking refrigerant discharge hole 17 is opened in the bottom surface of the case 2.

The refrigerant passage member 4 is made of a flexible silicone resin containing a thermally conductive filler such as silica powder, and its surface is covered with a gel that softens when it absorbs the refrigerant, giving it a flat rectangular shape. For example, a silicone hydrogel, in which silicone is bound to a hydrophilic gel, can be used as such a gel. Polyvinylpyrrolidone, polyvinyl chloride thermoplastic elastomer, etc. are used as the hydrophilic component.

In the battery unit 1, the battery cells 6 are placed on the refrigerant passage member 4, so that the refrigerant flows laterally along the underside of the lower battery cells 6 stacked flat, cooling the battery cells 6 from below. The upper battery cells 6 are cooled by the refrigerant flowing through the refrigerant passages 15 of the refrigerant passage member 4 through heat transfer via the thermally conductive material 9.

As shown in FIG. 3, a damaged portion 18 occurs in the refrigerant passage member 4, and the refrigerant flowing through the refrigerant passage 15 leaks from the damaged portion 18 and comes out onto the refrigerant passage member 4. As shown by the arrow, the leaked refrigerant passes through the leaked refrigerant discharge pipes 16a and 16b from the top surface of the refrigerant passage member 4, passes through the through hole 13 in the support plate 5, and is discharged into the gap between the support plate 5 and the bottom surface of the case 2, and then travels along the bottom surface of the case 2 and is discharged from the discharge hole 17.

When there is no refrigerant leakage, the refrigerant passage member 4 has a flat upper surface, supporting the battery cells with a wide surface and cooling them from the underside. When refrigerant leaks from the refrigerant passage member 4, the parts of the refrigerant passage member 4 that are wet with the refrigerant soften and collapse as the gel on the surface absorbs the refrigerant, i.e., the surface becomes concave. This makes it easier for the leaking refrigerant to flow from above the refrigerant passage member 4 toward the leaking refrigerant discharge pipe sections 16a, 16b, making it easier for it to be discharged.

The leaking refrigerant flows along the upper surface of the refrigerant passage member 4 toward the leaking refrigerant discharge pipes 16a, 16b, but because the leaking refrigerant discharge pipes 16a, 16b open between the positive and negative electrode terminals 7 of the battery cell 6, it is possible to prevent the leaking refrigerant from causing a short circuit. In addition, the leaking refrigerant discharge pipes 16a, 16b are positioned above the through holes 13 of the support plate 5, and the pipe holes are not blocked by the support plate 5, so the leaking refrigerant is also discharged smoothly from the leaking refrigerant discharge pipes 16a, 16b to the through holes 13.

Furthermore, since the surface on which the electrode terminal 7 and safety valve 8 of the battery cell 6 are provided does not need to be covered with a waterproof material to prevent short circuits, there is no impediment to the release of gas generated in the event of an internal short circuit in the battery cell 6 from the safety valve 8.

<Embodiment 2>
This embodiment will be described with reference to Figures 4 and 5. The battery unit 1 comprises a battery module 3 made up of a plurality of chargeable and dischargeable battery cells 6, a refrigerant passage member 4 having a refrigerant passage through which a liquid refrigerant passes, and a support plate 5 housed in a case 2.

The battery cells 6 have a rectangular parallelepiped shape with a pair of opposing side surfaces that are wider and flatter in the vertical direction than the other side surfaces, top surface, and bottom surface, and are provided with positive and negative electrode terminals 7 and a safety valve 8 on their top surfaces. In the battery module 3 of this embodiment, the multiple battery cells 6 are arranged side by side with their wide sides facing each other. The multiple battery cells 6 are electrically connected in series by bus bars (not shown).

The refrigerant passage member 4 is arranged so that liquid refrigerant flows laterally along the four side surfaces of each of the multiple battery cells. That is, the cooling passage member 4 has refrigerant passage sections 15a that extend on both sides of the battery module 3 in the direction in which the battery cells 6 are arranged side by side, and refrigerant passage sections 15b that connect the refrigerant passage sections 15a on both sides at both ends of the battery module 3 and between adjacent battery cells 6. A refrigerant inlet 15c and an outlet 15d are opened at both ends of the refrigerant passage member 4 in the cell arrangement direction. The upper end of the refrigerant passage member 4 is lower than the upper surface of the battery cells 6.

A leaking refrigerant discharge pipe section 16 for discharging leaking refrigerant is disposed around each battery cell 6 in the cooling passage member 4. The leaking refrigerant discharge pipe section 16 is a tube extending vertically connecting the upper and lower walls of the refrigerant passage member 4, and penetrates the refrigerant passage member 4 vertically to discharge refrigerant that has leaked from the refrigerant passage sections 15a and 15b onto the refrigerant passage member 4 below the refrigerant passage member 4.

The battery module 3 and the refrigerant passage member 4 are supported on the bottom surface of the case 2 by a support plate 5 similar to that of the first embodiment. Therefore, the support plate 5 has a through hole 13, similar to that of the first embodiment, and a gap 14 is provided between the support plate 5 and the bottom surface of the case 2. A leaking refrigerant discharge hole 17 is opened in the bottom surface of the case 2.

The pipe hole of the leaking refrigerant discharge pipe section 16 and the through hole 13 of the support plate 5 correspond vertically, and the pipe hole is smaller than the through hole 13. In other words, the through hole 13 of the support plate 5 is positioned so that the support plate 5 does not block the pipe hole of the leaking refrigerant discharge pipe section 16.

In this embodiment, when the refrigerant is passed through the refrigerant passage member 4, the refrigerant flows laterally along the periphery (side surface) of each battery cell 6, and the battery cell 6 is cooled by the refrigerant from its periphery.

The following describes a case where a damaged portion 18 occurs in the refrigerant passage member 4, and the refrigerant flowing through the refrigerant passage 15 leaks from the damaged portion 18 and comes out onto the refrigerant passage member 4. As shown by the arrow in the discharge route 19, the leaked refrigerant passes from the top surface of the refrigerant passage member 4 through the leaked refrigerant discharge pipe section 16, passes through the through hole 13 of the support plate 5, and is discharged into the gap between the support plate 5 and the bottom surface of the case 2, and is discharged from the discharge hole 17 along the bottom surface of the case 2. The leaked refrigerant discharge pipe section 16 is disposed above the through hole 13 of the support plate 5, and the pipe hole is not blocked by the support plate 5, so that the leaked refrigerant is discharged smoothly from the leaked refrigerant discharge pipe section 16 to the through hole 13.

Furthermore, since the surface on which the electrode terminal 7 and safety valve 8 of the battery cell 6 are provided does not need to be covered with a waterproof material to prevent short circuits, there is no impediment to the release of gas generated in the event of an internal short circuit in the battery cell 6 from the safety valve 8.

<Embodiment 3>
This embodiment will be described with reference to Figures 6 and 7. The battery unit 1 comprises a battery module 3 made up of a plurality of chargeable and dischargeable battery cells 6, a refrigerant passage member 4 having a refrigerant passage through which a liquid refrigerant passes, and a support plate 5 housed in a case 2.

The battery cells 6 have a rectangular parallelepiped shape that is flattened vertically, as in the second embodiment, and are provided with positive and negative electrode terminals 7 and a safety valve 8 on their upper surfaces. In this embodiment, the battery module 3 also has multiple battery cells 6 arranged side by side with their wide sides facing each other, and the multiple battery cells 6 are electrically connected in series by bus bars.

The refrigerant passage member 4 has a refrigerant passage section 15a that extends on both sides of the battery module 3 in the direction in which the battery cells 6 are arranged side by side, and a refrigerant passage section 15b that connects the refrigerant passage sections 15a on both sides at both ends of the battery module 3. A refrigerant inlet 15c and an outlet 15d are opened at both ends of the refrigerant passage member 4 in the cell arrangement direction. The upper end of the refrigerant passage member 4 is lower than the upper surface of the battery cells 6.

Thermal conductive material 9 is provided between the refrigerant passage portion 15a of the refrigerant passage member 4 and the battery cell 6, and between adjacent battery cells 6. The thermal conductive material 9 between the refrigerant passage member 4 and the battery cell 6 and the thermal conductive material 9 between the battery cells 6 are continuous. The height of the thermal conductive material 9 is higher than the height of the refrigerant passage member 4, and the upper end of the thermal conductive material 9 is higher than the upper end of the refrigerant passage member 4.

The cooling passage member 4 is provided with leaking refrigerant discharge pipes 16a, 16b on both sides of the battery module 3 (refrigerant passage section 15a) and on both ends of the battery module 3 (refrigerant passage section 15b). The leaking refrigerant discharge pipes 16a, 16b are tubular and extend vertically connecting the upper and lower walls of the refrigerant passage member 4, and discharge the refrigerant that has leaked from the refrigerant passage sections 15a, 15b onto the refrigerant passage member 4 below the refrigerant passage member 4.

On both sides of the battery module 3 (refrigerant passage section 15a), multiple leaking refrigerant discharge pipe sections 16a, 16b are arranged at intervals in the cell arrangement direction, and the leaking refrigerant discharge pipe section 16b located at the center of the arrangement direction has a larger inner diameter than the leaking refrigerant discharge pipe sections 16a located at both ends of the arrangement direction.

The battery module 3 and the refrigerant passage member 4 are supported on the bottom surface of the case 2 by a support plate 5 similar to that of the first embodiment. Therefore, the support plate 5 has a through hole 13, similar to that of the first embodiment, and a gap 14 is provided between the support plate 5 and the bottom surface of the case 2. A leaking refrigerant discharge hole 17 is opened in the bottom surface of the case 2.

The pipe holes of the leaking refrigerant discharge pipes 16a and 16b correspond vertically to the through holes 13 of the support plate 5, and the pipe holes are smaller than the through holes 13. In other words, the through holes 13 of the support plate 5 are positioned so that the support plate 5 does not block the pipe holes of the leaking refrigerant discharge pipes 16a and 16b.

When the refrigerant is passed through the refrigerant passage member 4, the refrigerant flows laterally along both side surfaces and both end surfaces of the battery module 3, thereby cooling the battery cells 6. Because the thermally conductive material 9 between the battery cells 6 is connected to the thermally conductive material 9 on both side surfaces of the battery module 3, heat is transferred from between the battery cells 6 through the thermally conductive material 9 and dissipated to both sides of the battery module. Therefore, heat does not build up between the battery cells 6.

If a damaged portion 18 occurs in the refrigerant passage member 4 and the refrigerant leaks onto the refrigerant passage member 4, the leaked refrigerant is discharged in the same manner as in embodiment 2. That is, the leaked refrigerant passes through the leaked refrigerant discharge pipes 16a and 16b from the top surface of the refrigerant passage member 4, passes through the through hole 13 of the support plate 5, and is discharged into the gap between the support plate 5 and the bottom surface of the case 2, as shown by the discharge route 19 with an arrow, and is discharged from the discharge hole 17 along the bottom surface of the case 2. The leaked refrigerant discharge pipes 16a and 16b are disposed above the through hole 13 of the support plate 5, and the pipe holes are not blocked by the support plate 5, so that the leaked refrigerant is discharged smoothly from the leaked refrigerant discharge pipes 16a and 16b to the through hole 13.

The battery cells 6 in the center of the battery module 3 in the cell arrangement direction are more likely to rise in temperature than the battery cells 6 at either end. By increasing the inner diameter of the leaking refrigerant discharge pipe section 16b in the center, the risk of a short circuit in the center is reduced, which is advantageous in improving safety.

The surface of the battery cell 6 on which the electrode terminal 7 and safety valve 8 are provided does not need to be covered with a waterproof material to prevent short circuits, so there is no impediment to the release of gas generated in the event of an internal short circuit in the battery cell 6 from the safety valve 8.

In this embodiment, since heat conductive material 9 is provided between the battery cells 6 instead of cooling passage members, this is advantageous for shortening the length of the battery module in the direction in which the battery cells are arranged side by side. Since the upper end of the heat conductive material 9 between the battery cells 6 is higher than the upper end of the refrigerant passage member 4, it is possible to prevent leaking refrigerant from entering between the battery cells 6.

<Embodiment 4>
This embodiment will be described with reference to Figures 8 and 9. The battery unit 1 comprises a battery module 3 made up of a plurality of chargeable and dischargeable battery cells 6, a refrigerant passage member 4 having a refrigerant passage through which a liquid refrigerant passes, and a support plate 5 housed in a case 2.

The battery cells 6 are cylindrical and stand upright, with a positive electrode terminal 7 equipped with a safety valve on the top surface. The battery module 3 is made up of multiple battery cells 6 arranged side by side in a zigzag pattern. The multiple battery cells 6 are electrically connected in series by bus bars.

The refrigerant passage member 4 extends in a zigzag shape in the direction in which the cells are arranged, weaving between the multiple battery cells 6 of the battery module 3. A refrigerant passage 15 is formed in this refrigerant passage member 4, through which liquid refrigerant passes. A refrigerant inlet 15a and outlet 15b open at one end of the refrigerant passage member 4. The upper end of the refrigerant passage member 4 is lower than the upper surfaces of the battery cells 6. A thermally conductive material 9 is provided between the inner wall of the case 2 and the refrigerant passage member 4, so as to encase the battery cells 6.

The refrigerant passage member 4 is provided with a plurality of leaking refrigerant discharge pipe sections 16 spaced apart in the direction in which the cells are arranged side by side. The leaking refrigerant discharge pipe sections 16 penetrate the refrigerant passage member 4 from top to bottom, and discharge the refrigerant that has leaked from the refrigerant passage 15 onto the refrigerant passage member 4 below the refrigerant passage member 4. The leaking refrigerant discharge pipe sections 16 are tubular and extend vertically connecting the upper and lower walls of the refrigerant passage member 4, so that the refrigerant does not leak from the refrigerant passage 15 into the leaking refrigerant discharge pipe sections 16.

The battery module 3 and the refrigerant passage member 4 are supported on the bottom surface of the case 2 by a support plate 5 similar to that of the first embodiment. Therefore, the support plate 5 has a through hole 13, similar to that of the first embodiment, and a gap 14 is provided between the support plate 5 and the bottom surface of the case 2. A leaking refrigerant discharge hole 17 is opened in the bottom surface of the case 2.

The pipe hole of the leaking refrigerant discharge pipe section 16 and the through hole 13 of the support plate 5 correspond vertically, and the pipe hole is smaller than the through hole 13. In other words, the through hole 13 of the support plate 5 is positioned so that the support plate 5 does not block the pipe hole of the leaking refrigerant discharge pipe section 16.

When the refrigerant is passed through the refrigerant passage member 4, the refrigerant flows laterally along the side of the battery cell 6, and the battery cell 6 is cooled by the refrigerant in the refrigerant passage member 4, which absorbs heat from the battery cell 6 via the thermally conductive material 9.

When a damaged portion 18 occurs in the refrigerant passage member 4 and the refrigerant leaks onto the refrigerant passage member 4, the leaking refrigerant passes through the leaking refrigerant discharge pipe section 16 from the top surface of the refrigerant passage member 4, passes through the through hole 13 of the support plate 5, is discharged into the gap between the support plate 5 and the bottom surface of the case 2, and is discharged from the discharge hole 17 along the bottom surface of the case 2, as shown by the discharge route 19 by the arrow. The leaking refrigerant discharge pipe section 16 is disposed above the through hole 13 of the support plate 5, and the pipe hole is not blocked by the support plate 5, so that the leaking refrigerant is discharged smoothly from the leaking refrigerant discharge pipe section 16 to the through hole 13.

The surface of the battery cell 6 on which the electrode terminal 7 and safety valve 8 are provided does not need to be covered with a waterproof material to prevent short circuits, so there is no impediment to the release of gas generated in the event of an internal short circuit in the battery cell 6 from the safety valve 8.

＜Other＞
In embodiments 1 and 3, the inner diameter of the leaking refrigerant discharge pipe section 16b at the center of the cell arrangement direction is increased, but in other embodiments, the inner diameter of the leaking refrigerant discharge pipe section 16b at the center of the cell arrangement direction can be similarly increased.

REFERENCE SIGNS LIST 1 battery unit 2 case 3 battery module 4 refrigerant passage member 5 support plate 6 battery cell 7 electrode terminal 8 safety valve 9 thermally conductive material 13 through hole 14 gap 15 refrigerant passage 15a refrigerant passage section 15b communication passage section 15c inlet 15d outlet 16 leaking refrigerant discharge pipe section 16a, 16b leaking refrigerant discharge pipe section 17 leaking refrigerant discharge hole 18 damaged location 19 discharge route

Claims (7)

A vehicle battery unit including a plurality of battery cells and a refrigerant passage member having a refrigerant passage through which a liquid refrigerant for cooling the battery cells passes,
the refrigerant passage member is provided so that the refrigerant flows laterally along bottom surfaces or side surfaces of the plurality of battery cells,
the refrigerant passage member includes a plurality of leaking refrigerant discharge pipe portions that vertically penetrate the refrigerant passage member and discharge refrigerant that has leaked from the refrigerant passage member from above the refrigerant passage member to below the refrigerant passage member. In claim 1,
a case that houses the plurality of battery cells and the refrigerant passage member;
a plate that is disposed within the case with a gap between it and a bottom surface of the case and supports the plurality of battery cells;
the plate has a through hole that vertically penetrates the plate and guides the leaking refrigerant discharged downward from the leaking refrigerant discharge pipe portion to a bottom surface of the case,
A vehicle battery unit, characterized in that a discharge port for discharging the leaked refrigerant is opened in a bottom surface of the case. In claim 2,
Each of the plurality of battery cells has a flat rectangular parallelepiped shape with upper and lower surfaces that are wider than the side surfaces, and is provided with an electrode terminal and a safety valve on one side surface of the battery cell;
the refrigerant passage member is placed on the plate so that the refrigerant flows laterally along undersides of the plurality of battery cells, and the plurality of battery cells are arranged side-by-side and placed on the plate via the refrigerant passage member. In claim 3,
The vehicle battery unit is characterized in that the refrigerant passage member is formed from a flexible silicone resin containing a thermally conductive filler, and its surface is covered with a gel that softens when it absorbs the refrigerant, giving it a flattened rectangular shape. In claim 2,
each of the plurality of battery cells has a rectangular parallelepiped shape in which a pair of opposing side surfaces are wider than the other side surfaces, the top surface, and the bottom surface, and is provided with an electrode terminal and a safety valve on its top surface;
The plurality of battery cells are arranged side by side with the broad side surfaces facing each other,
the refrigerant passage member is arranged so that the refrigerant flows laterally along four side surfaces of each of the plurality of battery cells, and the leaking refrigerant discharge pipe portion is disposed around each of the plurality of battery cells. In claim 2,
each of the plurality of battery cells has a rectangular parallelepiped shape in which a pair of opposing side surfaces are wider than the other side surfaces, the top surface, and the bottom surface, and is provided with an electrode terminal and a safety valve on its top surface;
The plurality of battery cells are arranged side by side with the broad side surfaces facing each other,
the refrigerant passage members extend on both sides of the plurality of juxtaposed battery cells in the juxtaposed direction of the battery cells,
a thermally conductive material is provided between the refrigerant passage member and the battery cell and between adjacent battery cells, the thermally conductive material between the refrigerant passage member and the battery cell and the thermally conductive material between adjacent battery cells are continuous,
a height of the heat conductive material is greater than a height of the refrigerant passage member, and an upper end of the heat conductive material is greater than an upper end of the refrigerant passage member. In any one of claims 3 to 6,
a leakage refrigerant discharge pipe portion located at a center of a direction in which the plurality of battery cells are arranged side by side has an inner diameter larger than the leakage refrigerant discharge pipe portions located at both ends.