Vehicle battery unit

Abstract

To prevent a battery cell 6 from short-circuiting even when a liquid coolant leaks from a coolant passage member 4 of a vehicle battery unit 1.SOLUTION: A battery unit 1 includes a plurality of battery cells 6, and a refrigerant passage member 4 formed with a refrigerant passage 15 for passing a liquid refrigerant for cooling the battery cells. The refrigerant passage member 4 is provided such that the liquid refrigerant flows laterally along the bottom surfaces or side surfaces of the plurality of battery cells 6. The refrigerant passage member 4 includes a plurality of leaked refrigerant discharge pipe portions 16 that vertically penetrate the refrigerant passage member 4 and discharge the liquid refrigerant leaked above the refrigerant passage member 4 to the lower side of the refrigerant passage member 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery unit for a vehicle. [Background technology]

[0002] 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 a liquid refrigerant comes into direct contact with the battery cells.

[0003] Patent Document 1 describes the placement of corrugated cooling tubes, through which a refrigerant flows, between battery cell rows made up of multiple aligned cylindrical battery cells, in such a way that they thread between the battery cells in adjacent rows. It also describes the provision of a thermally conductive medium between the cooling tubes and the battery cells. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-528406 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the above cooling method, there is a concern that refrigerant leakage due to deterioration of refrigerant passage members such as cooling tubes over time or damage due to impact may cause a short circuit (liquid junction) in the battery cell. In other words, if refrigerant leaks from the refrigerant passage members and accumulates on the refrigerant passage members, the refrigerant may come into contact with the electrode terminals of the battery cells, causing a short circuit.

[0006] Therefore, an object of the present invention is to prevent short-circuiting of battery cells even if liquid refrigerant leaks from refrigerant passage members. [Means for solving the problem]

[0007] SUMMARY OF THE PRESENT DISCLOSURE In order to solve the above-mentioned problems, the present invention is capable of discharging leaked refrigerant from above a refrigerant passage member to below the refrigerant passage member.

[0008] 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.

[0009] This prevents leaking refrigerant from accumulating on the refrigerant passage members, thereby preventing short circuits in the battery cells due to leaking refrigerant.

[0010] 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.

[0011] 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. Since 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 opened in the bottom of the case without stagnation.

[0012] In one embodiment, each of the plurality of battery cells has a flattened rectangular parallelepiped shape with upper and lower surfaces wider than the side surfaces, and includes an electrode terminal and a safety valve on one side 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.

[0013] Therefore, each battery cell can be cooled from its underside by the refrigerant in the refrigerant passage member. Even if refrigerant leaks from the refrigerant passage member, it can be discharged downward from above the refrigerant passage member by the leaking refrigerant discharge pipe, so the refrigerant does not accumulate on the refrigerant passage member and short-circuiting of the battery cells is prevented.

[0014] 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 from a flexible silicone resin containing a thermally conductive filler, and has a flattened rectangular shape with its surface covered with a gel that softens when it absorbs the refrigerant.

[0015] Therefore, when the refrigerant is not leaking, the refrigerant passage member has a flat upper surface, supporting the multiple battery cells over a wide surface and cooling them from below. When the 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.

[0016] 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 provided 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.

[0017] Therefore, each battery cell can be cooled from its periphery (side surface) by the refrigerant in the refrigerant passage member. Even if refrigerant leaks from the refrigerant passage member, it can be discharged downward from above the refrigerant passage member by the leaking refrigerant discharge pipe, so the refrigerant does not accumulate on the refrigerant passage member and short-circuiting of the battery cells is prevented.

[0018] 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 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, 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.

[0019] Therefore, each battery cell can be cooled by the refrigerant in the refrigerant passage member through heat transfer by the thermally conductive material. Because a thermally conductive material is provided between the battery cells instead of a cooling passage member, 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.

[0020] In one embodiment, the leaking refrigerant discharge pipe section located at the center in the juxtaposition direction of the plurality of battery cells has a larger inner diameter than the leaking refrigerant discharge pipe sections located at both ends.

[0021] The battery cells in the center of the battery cell arrangement direction are more likely to rise in temperature than the battery cells at either end. By increasing the inner diameter of the leaking refrigerant discharge pipe section in the center, the risk of short circuiting in the center is reduced, which is advantageous in improving safety. Effect of the Invention

[0022] According to the present invention, the refrigerant passage member is provided with a plurality of leaking refrigerant discharge pipe sections that discharge the refrigerant from above the refrigerant passage member to below the refrigerant passage member. This prevents leaking refrigerant from accumulating above the refrigerant passage member, which is advantageous in preventing short-circuiting of battery cells due to leaking refrigerant. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is a vertical cross-sectional view of the battery unit according to the first embodiment. [Diagram 2] FIG. 2 is a perspective view showing a refrigerant passage member, a support plate, and a case according to the first embodiment. [Diagram 3] 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 damaged. FIG. [Figure 4] FIG. 6 is a cross-sectional view of a battery unit according to a second embodiment. [Diagram 5] Cross-sectional view of line VV in Figure 4. [Figure 6] FIG. 11 is a cross-sectional view of a battery unit according to a third embodiment. [Figure 7] Cross-sectional view of line VV in Figure 6. [Figure 8] FIG. 11 is a cross-sectional view of a battery unit according to a fourth embodiment. [Figure 9] 9 is a cross-sectional view taken along line IX-IX in FIG. 8, with the thermal conductive material omitted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its application, or its uses.

[0025] <Embodiment 1> The vehicle battery unit 1 shown in Fig. 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 battery cells 6 that are chargeable and dischargeable. Each battery cell 6 has a flattened rectangular parallelepiped shape in which the areas of its upper and lower faces are larger than the area of ​​its side faces, i.e., its thickness in the vertical direction is thin, and one of its sides is provided with positive and negative electrode terminals 7 and a safety valve 8. The plurality of battery cells 6 are electrically connected in series by bus bars (not shown).

[0026] In the battery module 3 of this example, a plurality of battery cells 6 are stacked in the thickness direction in a flat stacked state, and a plurality of these stacked battery cells 6 are arranged side by side, that is, arranged side by side in the horizontal direction. In the flat stacked cells of this example, two battery cells 6 are stacked, but the number of layers 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. As the thermally conductive material 9, for example, a silicone resin mixed with a thermally conductive filler such as silica fine powder can be used.

[0027] In the battery unit 1, the refrigerant passage member 4 is placed on a support plate 5, and the battery module 3 is placed on the support plate 5 with the refrigerant passage member 4 interposed therebetween.

[0028] As shown in Fig. 2, the support plate 5 is made up of multiple plate materials 12 stretched across two parallel support bars 11 extending laterally. 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 Fig. 1, between the support plate 5 and the bottom surface of the case 2, there is a gap 14 that corresponds to the height of the support bars 11.

[0029] As shown in Fig. 2, the refrigerant passage member 4 has a flattened rectangular parallelepiped shape with a height that is shorter 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 through which a liquid refrigerant such as water passes is formed in this refrigerant passage member 4. 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 outlet 15b of the refrigerant passage member 4 open at one end of the case 2.

[0030] The refrigerant passage member 4 is provided with a plurality of leaking refrigerant discharge pipe sections 16a, 16b spaced apart in the direction in which the cells are arranged side by side. The leaking refrigerant discharge pipe sections 16a, 16b vertically penetrate the refrigerant passage member 4 and discharge the refrigerant 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 in which the cells are arranged side by side has a larger inner diameter than the leaking refrigerant discharge pipe sections 16a located at both ends in the direction in which the cells are arranged side by side.

[0031] The pipe holes of the leaking refrigerant discharge pipe sections 16a, 16b are provided at a position corresponding to directly below the center between the positive and negative electrode terminals 7 of the battery cell 6. The pipe holes of the leaking refrigerant discharge pipe sections 16a, 16b and the through hole 13 of the support plate 5 correspond vertically, and the pipe holes are 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 holes of the leaking refrigerant discharge pipe sections 16a, 16b. A leaking refrigerant discharge hole 17 is opened in the bottom surface of the case 2.

[0032] The refrigerant passage member 4 is made of a soft 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, forming a flat rectangular parallelepiped shape. For example, a silicone hydrogel in which silicone is bound to a hydrophilic gel can be used as the gel. Polyvinylpyrrolidone, polyvinyl chloride thermoplastic elastomer, etc. are used as the hydrophilic component.

[0033] In the battery unit 1, the battery cells 6 are placed on the refrigerant passage members 4, so that the refrigerant flows laterally along the undersides of the lower battery cells 6 stacked flat, cooling the undersides of the battery cells 6. The upper battery cells 6 are cooled by the refrigerant flowing through the refrigerant passages 15 of the refrigerant passage members 4 through heat transfer via the thermally conductive material 9.

[0034] 3, a case will be described in which 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 upper surface of the refrigerant passage member 4 through the leaked refrigerant discharge pipe portions 16a, 16b, passes through the through hole 13 in the support plate 5, 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 to be discharged from the discharge hole 17.

[0035] When there is no refrigerant leaking, the refrigerant passage member 4 has a flat upper surface, supporting the battery cells over a wide surface and cooling them from below. When the refrigerant leaks from the refrigerant passage member 4, the portions 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 pipes 16a, 16b, making it easier for it to be discharged.

[0036] The leaking refrigerant flows along the upper surface of the refrigerant passage member 4 toward the leaking refrigerant discharge pipe sections 16a, 16b, but because the leaking refrigerant discharge pipe sections 16a, 16b open between the positive and negative electrode terminals 7 of the battery cells 6, it is possible to prevent the discharged leaking refrigerant from causing a short circuit. In addition, because the leaking refrigerant discharge pipe sections 16a, 16b are positioned above the through-holes 13 in the support plate 5 and the pipe holes are not blocked by the support plate 5, the leaking refrigerant is also smoothly discharged from the leaking refrigerant discharge pipe sections 16a, 16b to the through-hole 13.

[0037] 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.

[0038] <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 in which a refrigerant passage for passing a liquid refrigerant is formed, and a support plate 5 housed in a case 2.

[0039] Each battery cell 6 has 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 is provided with positive and negative electrode terminals 7 and a safety valve 8 on its top surface. In the battery module 3 of this embodiment, the multiple battery cells 6 are arranged side by side with their wider side surfaces facing each other. The multiple battery cells 6 are electrically connected in series by bus bars (not shown).

[0040] 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 open 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 top surfaces of the battery cells 6.

[0041] 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 tubular 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, 15b onto the refrigerant passage member 4 below the refrigerant passage member 4.

[0042] 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 embodiment 1. Thus, like embodiment 1, the support plate 5 is provided with a through hole 13, and a gap 14 is provided between the support plate 5 and the bottom surface of the case 2. A leaked refrigerant discharge hole 17 is opened in the bottom surface of the case 2.

[0043] The pipe hole of the leaking refrigerant discharge pipe section 16 and the through hole 13 of the support plate 5 correspond to each other 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 arranged so that the support plate 5 does not block the pipe hole of the leaking refrigerant discharge pipe section 16.

[0044] In this embodiment, when the coolant is caused to flow through the coolant passage member 4, the coolant flows laterally along the periphery (side surface) of each battery cell 6, and the battery cells 6 are cooled by the coolant from the periphery.

[0045] A case will be described 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 leaking refrigerant passes from the upper surface of the refrigerant passage member 4 through the leaking refrigerant discharge pipe portion 16, passes through the through hole 13 in 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. The leaking refrigerant discharge pipe portion 16 is disposed above the through hole 13 in the support plate 5, and the pipe hole is not blocked by the support plate 5, so that the leaking refrigerant is smoothly discharged from the leaking refrigerant discharge pipe portion 16 to the through hole 13.

[0046] 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.

[0047] <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 in which a refrigerant passage for passing a liquid refrigerant is formed, and a support plate 5 housed in a case 2.

[0048] Similar to the second embodiment, the battery cell 6 has a rectangular parallelepiped shape that is flattened in the vertical direction, and has positive and negative electrode terminals 7 and a safety valve 8 on its upper surface. In the present 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.

[0049] The refrigerant passage member 4 includes 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. A refrigerant inlet 15c and an outlet 15d open 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 top faces of the battery cells 6.

[0050] Thermally conductive materials 9 are provided between the refrigerant passage portions 15a of the refrigerant passage members 4 and the battery cells 6, and between adjacent battery cells 6. The thermally conductive materials 9 between the refrigerant passage members 4 and the battery cells 6 are continuous with the thermally conductive materials 9 between the battery cells 6. The height of the thermally conductive materials 9 is higher than the height of the refrigerant passage members 4, and the upper end of the thermally conductive materials 9 is higher than the upper end of the refrigerant passage members 4.

[0051] The cooling passage member 4 is provided with leaking refrigerant discharge pipes 16a, 16b on both sides (refrigerant passage section 15a) of the battery module 3 and on both ends (refrigerant passage section 15b) of the battery module 3. 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.

[0052] On both sides (refrigerant passage section 15a) of the battery module 3, multiple leaking refrigerant discharge pipe sections 16a, 16b are arranged at intervals in the cell juxtaposition direction, and the leaking refrigerant discharge pipe section 16b located at the center in the juxtaposition direction has a larger inner diameter than the leaking refrigerant discharge pipe sections 16a located at both ends in the juxtaposition direction.

[0053] 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 embodiment 1. Thus, like embodiment 1, the support plate 5 is provided with a through hole 13, and a gap 14 is provided between the support plate 5 and the bottom surface of the case 2. A leaked refrigerant discharge hole 17 is opened in the bottom surface of the case 2.

[0054] The pipe holes of the leaking refrigerant discharge pipe parts 16a, 16b and the through hole 13 of the support plate 5 correspond vertically, and the pipe holes are 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 holes of the leaking refrigerant discharge pipe parts 16a, 16b.

[0055] When a refrigerant is caused to flow through the refrigerant passage members 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 materials 9 between the battery cells 6 are connected to the thermally conductive materials 9 on both side surfaces of the battery module 3, heat is transferred from between the battery cells 6 through the thermally conductive materials 9 and dissipated to both sides of the battery module. Therefore, heat does not build up between the battery cells 6.

[0056] 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 the second embodiment. That is, as shown by the arrow in the discharge route 19, the leaked refrigerant passes from the upper surface of the refrigerant passage member 4 through the leaked refrigerant discharge pipe portions 16a, 16b, 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. The leaked refrigerant discharge pipe portions 16a, 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 smoothly discharged from the leaked refrigerant discharge pipe portions 16a, 16b to the through hole 13.

[0057] The battery cells 6 at the center of the cell arrangement direction of the battery module 3 are more likely to rise in temperature than the battery cells 6 at both ends. Therefore, by making the inner diameter of the leaking refrigerant discharge pipe section 16b at the center larger, the risk of short circuit at the center is reduced, which is advantageous in improving safety.

[0058] Since the surface on which the electrode terminals 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.

[0059] 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 ends of the heat conductive materials 9 between the battery cells 6 are higher than the upper ends of the refrigerant passage members 4, it is possible to prevent leaking refrigerant from entering between the battery cells 6.

[0060] <Embodiment 4> This embodiment will be described with reference to Figures 8 and 9. A battery unit 1 is configured by housing, in a case 2, a battery module 3 made up of a plurality of chargeable and dischargeable battery cells 6, a refrigerant passage member 4 in which a refrigerant passage through which a liquid refrigerant passes, and a support plate 5.

[0061] 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 formed by arranging multiple battery cells 6 side by side in a zigzag pattern in the horizontal direction. The multiple battery cells 6 are electrically connected in series by bus bars.

[0062] 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 for passing a liquid refrigerant is formed in this refrigerant passage member 4. 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.

[0063] The refrigerant passage member 4 is provided with a plurality of leaking refrigerant discharge pipe sections 16 provided at intervals in the direction in which the cells are arranged side by side. The leaking refrigerant discharge pipe sections 16 vertically penetrate the refrigerant passage member 4 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.

[0064] 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 embodiment 1. Thus, like embodiment 1, the support plate 5 is provided with a through hole 13, and a gap 14 is provided between the support plate 5 and the bottom surface of the case 2. A leaked refrigerant discharge hole 17 is opened in the bottom surface of the case 2.

[0065] The pipe hole of the leaking refrigerant discharge pipe section 16 and the through hole 13 of the support plate 5 correspond to each other 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 arranged so that the support plate 5 does not block the pipe hole of the leaking refrigerant discharge pipe section 16.

[0066] When the refrigerant is caused to flow through the refrigerant passage member 4, the refrigerant flows laterally along the side surfaces of the battery cells 6, and the battery cells 6 are cooled as heat is absorbed by the refrigerant in the refrigerant passage member 4 via the thermally conductive material 9.

[0067] 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 from the upper surface of the refrigerant passage member 4 through the leaking refrigerant discharge pipe section 16, passes through the through hole 13 in the support plate 5, 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 to be discharged from the discharge hole 17, as shown by the arrow in the discharge route 19. The leaking refrigerant discharge pipe section 16 is disposed above the through hole 13 in the support plate 5, and the pipe hole is not blocked by the support plate 5, so that the leaking refrigerant can be smoothly discharged from the leaking refrigerant discharge pipe section 16 to the through hole 13.

[0068] Since the surface on which the electrode terminals 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.

[0069] <Other> In the first and third embodiments, the inner diameter of the leaking refrigerant discharge pipe portion 16b at the center in the cell arrangement direction is increased, but in other embodiments, the inner diameter of the leaking refrigerant discharge pipe portion 16b at the center in the cell arrangement direction can be increased similarly. [Explanation of symbols]

[0070] 1 Battery unit 2 Cases 3 Battery Module 4 Refrigerant passage parts 5 Support Plate 6 Battery Cells 7 Electrode terminal 8. Safety valve 9. Thermal Conductive Materials 13 Through hole 14 Gap 15 Refrigerant passage 15a Refrigerant passage section 15b Connecting passage 15c entrance 15d exit 16 Leaking refrigerant discharge pipe 16a, 16b Leaking refrigerant discharge pipe section 17. Leaking refrigerant exhaust hole 18 Damaged area 19 Emission Route

Claims

1. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

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