JP2024065463A - Battery cooling heat sink - Google Patents

Abstract

[Problem] To configure a battery cooling heat sink that can maintain a uniform temperature for each battery even when cooling multiple batteries. [Solution] The heat sink has a cooling main body 2 that removes heat from the battery B via a heat exchange wall 21 that contacts the battery B when a cooling fluid L is supplied from an inlet, and a discharge section that discharges the cooling fluid L supplied to the cooling main body 2, the cooling main body 2 has a partition plate 25 that forms multiple cooling flow paths F by dividing an area in the width direction perpendicular to the flow direction of the cooling fluid into multiple parts on the inner surface side of the heat exchange wall 21, and the cooling main body 2 has a leak allowance section C that allows leakage of the cooling fluid between adjacent cooling flow paths F with the partition plate 25 in between. [Selected Figure] Figure 3

Description

The present invention relates to a heat sink for cooling batteries.

Patent document 1 describes a configuration that uses a battery cooling heat sink in which multiple single cells are arranged at a predetermined interval inside a box-shaped secondary battery module, and a refrigerant is passed through the inside of a cooling mechanism that contacts the secondary battery module, making it possible to cool the multiple single cells inside the secondary battery module.

This patent document describes a configuration in which multiple parallel paths are formed inside the cooling mechanism, and refrigerant flows in opposite directions through adjacent paths, making it possible to equalize the temperature distribution within the secondary battery module (see Figures 2A and 2B).

JP 2015-82353 A

For example, if a case-shaped cooling mechanism placed in contact with the battery to cool the battery is a simple duct-shaped heat sink with a cooling fluid flowing inside, as described as an issue in Patent Document 1, the cooling performance will be reduced downstream compared to the upstream side of the refrigerant flow, and the required cooling cannot be performed sufficiently downstream.

To address this issue, as described in Patent Document 1, multiple parallel flow paths (called paths in the document) are formed inside the heat sink, and the refrigerant flows in opposite directions through adjacent flow paths. However, even with a configuration in which the refrigerant flows in opposite directions through adjacent flow paths, there is a concern that the temperature distribution in the areas of the heat sink that come into contact with each battery is not constant, and heat from the batteries cannot be removed evenly.

For these reasons, when cooling multiple batteries, a heat sink for cooling batteries is required that can maintain each battery at a uniform temperature.

The characteristic configuration of the heat sink for cooling a battery according to the present invention is that it has an inlet section into which a cooling fluid flows, a cooling main body section that removes heat from the battery by supplying the cooling fluid from the inlet section, and a discharge section that discharges the cooling fluid supplied to the cooling main body section, the cooling main body section has a partition plate that forms a plurality of cooling flow paths by dividing a region in a width direction perpendicular to the flow direction of the cooling fluid into a plurality of parts, and the cooling main body section has a leak tolerance section that allows the cooling fluid to leak between the cooling flow paths adjacent to each other across the partition plate.

For example, even if the cross-sectional area of each of the multiple cooling flow paths is equal, there is a partition plate in each cooling flow path, and cooling fluid does not usually flow through the partition plate portion, so there is variation in the amount of heat removed from the battery in the width direction (longitudinal direction) of each battery. Furthermore, when cooling multiple batteries, the amount of heat removed from the batteries by the cooling fluid flowing through each of the multiple cooling flow paths may differ depending on the relative positions of the multiple batteries close to the outer surface of the cooling main body. When differences in the temperature of the cooling fluid flowing through the multiple cooling flow paths occur in this way, the temperature distribution on the outer surface of the cooling main body becomes uneven, making it difficult to remove heat from the batteries evenly.

In contrast, this configuration has a leak-permitting portion that allows some of the cooling fluid to leak between adjacent cooling flow paths, so even if the temperatures of the cooling fluid flowing through adjacent cooling flow paths are different, the temperature difference can be reduced by the leakage of the cooling fluid, and the temperature of the outer surface of the heat sink in contact with the batteries can be uniformly reduced, making it possible to remove heat from the batteries. In addition, because the leak-permitting portion allows the cooling fluid to flow through the partition plate portion, the amount of heat removed from the batteries can be uniform across the width of each battery. Therefore, a battery cooling heat sink has been configured that can maintain each battery at a uniform temperature even when cooling multiple batteries.

As another configuration, the cooling body may have the cooling fluid flow in the same direction in multiple cooling flow paths partitioned by the partition plate.

This allows the cooling fluid to flow in the same direction through multiple cooling flow paths, which not only simplifies the structure, but also increases the heat exchange efficiency of the cooling fluid by flowing it linearly through multiple cooling flow paths, thereby improving cooling performance.

As another configuration, the thickness of the partition plates may be thinner downstream of the cooling flow passage than upstream, and the width of the downstream side of the cooling flow passage may be wider than the width of the upstream side of the cooling flow passage in the parallel direction in which the cooling flow passages are arranged.

This allows the heat exchange area where the cooling flow path removes heat from the battery on the downstream side to be larger than the heat exchange area where the cooling flow path removes heat from the battery on the upstream side. For this reason, when the cooling fluid flows from the upstream side to the downstream side, the amount of heat that the cooling fluid removes from the battery on the upstream side is suppressed, and the temperature of the cooling fluid does not rise significantly. Also, when the cooling fluid reaches from the upstream side to the downstream side, the downstream side can remove heat from the battery over a larger heat exchange surface than the upstream side, which reduces the temperature difference of the cooling fluid between the upstream and downstream sides and makes it possible to equalize the temperature of each battery.

As another configuration, the cooling body may have a heat exchange wall adjacent to the battery and a bottom wall facing the heat exchange wall, and the partition plate may be supported in such a manner that one end of the partition plate in the plate height direction corresponding to the space between the heat exchange wall and the bottom wall is connected and fixed to the inner surface of the bottom wall without any gaps, and the other end of the partition plate in the plate height direction forms a gap on the inner surface of the heat exchange wall as the leak-permitting portion.

With this, the cooling fluid does not leak into the adjacent cooling flow passage at the fixed portion on the bottom wall side of one end of the partition plate in the plate height direction, but the heat medium is allowed to leak into the adjacent cooling flow passage in the gap formed as a leak-permitting portion on the heat exchange wall side of the other end of the partition plate in the plate height direction. In this configuration, the cooling fluid leaks between the respective cooling flow passages on the inner surface of the heat exchange wall adjacent to the battery, thereby reducing the temperature difference between the cooling flow passages adjacent to each other across the partition plate, making it possible to uniform the temperature distribution of the heat exchange wall.

As another configuration, one end of the partition plate in the plate height direction may be fixed to the bottom wall by welding, and the other end of the partition plate may be disposed inside a recess formed in the heat exchange wall.

With this, one end of the partition plate in the plate height direction is firmly fixed to the bottom wall, and the other end of the partition plate in the plate height direction allows leakage of cooling fluid between the inside of the recess in the heat exchange wall. With this configuration, only one end of the partition plate in the plate height direction is welded and fixed, which reduces the number of welding points and reduces manufacturing costs.

FIG. 2 is an overall view of a heat sink for cooling a battery. 4 is a cross-sectional view showing the configuration of an inlet portion, a cooling main body portion, and an outlet portion. FIG. 4 is a cross-sectional view showing the positional relationship between a cooling main body and a partition plate. FIG. 5 is an enlarged cross-sectional view showing the positional relationship between an extended end portion of a partition plate and a leak allowance portion. FIG. FIG. 4 is a cross-sectional view showing the plate thickness of a partition plate. FIG. 11 is a cross-sectional view showing the configuration of a leak allowing portion according to another embodiment (a). 13 is a cross-sectional view showing the configuration of a leak allowance portion of another embodiment (b). FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Basic configuration]
As shown in Figures 1 and 2, a battery cooling heat sink A is configured to have a cylindrical inlet section 1 into which cooling fluid L flows, a duct-shaped cooling main body section 2 to which the cooling fluid L is supplied from the inlet section 1, and a cylindrical outlet section 3 from which the cooling fluid L supplied to the cooling main body section 2 is discharged, and also has a cooling fluid pump 4 which supplies the cooling fluid L to the inlet section 1, and a heat dissipation section 5 which dissipates heat from the cooling fluid L discharged from the outlet section 3.

The battery cooling heat sink A circulates the cooling fluid L along the arrangement direction of multiple batteries B (four in FIG. 2) by driving the cooling fluid pump 4, removing heat from the batteries B and suppressing the temperature rise of the batteries B. The cooling main body 2 has a heat exchange wall 21 that is placed close to a specific surface of the battery B in a state in which a heat transfer sheet 20 is sandwiched between the battery B. The heat transfer sheet 20 is made of a resin material that has good thermal conductivity and can be flexibly deformed, and achieves good thermal conduction by being in close contact with the specific surface of the battery B and the outer surface of the heat exchange wall 21. The number of multiple batteries B is not particularly limited, and is set appropriately according to the cooling performance of the battery cooling heat sink A.

In this battery cooling heat sink A, the cooling fluid L is a cooling water such as long-life coolant (LLC) containing ethylene glycol or propylene glycol, insulating oil such as paraffin, or a refrigerant such as hydrofluorocarbon (HFC) or hydrofluoroolefin (HFO).

The battery cooling heat sink A, in an EV vehicle that runs on power supplied from battery B, removes heat from battery B and suppresses the rise in temperature of battery B. It is assumed that battery B will be a rechargeable secondary battery such as a lithium-ion battery.

[Cooling main body]
3, the cooling body 2 is formed into a duct shape having a rectangular cross section. The cooling body 2 includes a heat exchange wall 21 adjacent to the outer surface of the battery B, a bottom wall 22 disposed opposite the heat exchange wall 21, and a pair of side walls 23 integrally formed with the bottom wall 22. The cooling body 2 includes a plurality of partition plates 25 inside the cooling body 22 that divide the internal space into a plurality of cooling flow paths F. The heat exchange wall 21, the bottom wall 22, the side walls 23, and the partition plates 25 are made of aluminum.

The horizontal direction of the cooling body 2 shown in FIG. 3 is sometimes referred to as the width direction (the direction perpendicular to the flow direction of the cooling fluid L), and the vertical direction shown in FIG. 3 is sometimes referred to as the height direction. Also, the partition plate 25 along the height direction of the cooling body 2 is sometimes referred to as the plate height direction, and the thickness of the partition plate 25 along the width direction of the cooling body 2 when viewed in the direction shown in FIG. 3 is sometimes referred to as the plate thickness.

By dividing the internal space of the cooling body 2 with multiple partition plates 25 in this manner, multiple cooling flow paths F are formed as shown in Figures 2 and 3, and the cooling fluid L supplied from the inlet 1 flows in the direction shown by the arrows in Figure 2 in the multiple cooling flow paths F.

As shown in FIG. 5, the multiple partition plates 25 are set so that the upstream end plate thickness T1, which is the end on the upstream side of the flow of the cooling fluid L, is thicker than the downstream end plate thickness T2, which is the end on the downstream side (see also FIG. 2). As a result, the partition plates 25 are formed in a tapered shape overall in the plate thickness direction, and as shown in FIGS. 2 and 5, the flow path width of the multiple cooling flow paths F becomes wider toward the downstream side. Note that instead of forming the partition plates 25 in a tapered shape, a step may be provided in the partition plates 25 to set the upstream end plate thickness T1 thicker than the downstream end plate thickness T2.

As shown in FIG. 3, the heat exchange wall 21 is a flat plate, and is formed into a cylindrical shape by welding the ends of the heat exchange wall 21 in the width direction to the ends of a pair of side walls 23 using a technique such as laser welding.

The partition plate 25 is welded and fixed by a technique such as laser welding with the base end facing the bottom wall 22 in the plate height direction in contact with the bottom wall 22. As shown in Figs. 3 and 4, the extension end 25a facing the heat exchange wall 21 in the plate height direction of the partition plate 25 is disposed inside the recess 21g formed on the inner surface side (opposite the battery B) of the heat exchange wall 21. It is also possible to form a small gap between the partition plate 25 and the inner surface side of the heat exchange wall 21 without forming the recess 21g, with the extension end 25a as a free end. It is also possible to provide the recess 21g only on the downstream side of the inner surface side of the heat exchange wall 21, and not provide a gap between the partition plate 25 and the inner surface side of the heat exchange wall 21 on the upstream side. It is preferable that the area where the gap is provided between the partition plate 25 and the inner surface side of the heat exchange wall 21 is at least downstream of the center of the heat exchange wall 21.

In this way, by arranging the extended end portion 25a of the partition plate 25 inside the recess 21g, a leak-permitting portion C is formed that allows the cooling fluid L to leak between the cooling flow paths F located adjacent to each other across the partition plate 25.

As a specific configuration of the leak-permitting portion C, a pair of guide portions 21a are formed along the flow direction of the cooling fluid L at a position on the inner surface side of the heat exchange wall 21 corresponding to the partition plate 25, and a groove-shaped recess 21g is formed between the pair of guide portions 21a. In particular, in the leak-permitting portion C, the extending end portion 25a of the partition plate 25 is arranged at a position that forms a gap between each of the pair of guide portions 21a and the inner surface side of the heat exchange wall 21. The recess 21g may be formed by processing to form a groove on the inner surface side of the heat exchange wall 21.

As a result, the cooling fluid L does not flow between adjacent cooling flow paths F at the welded points between the partition plate 25 and the bottom wall 22, and leakage of the cooling fluid L is permitted in the gap between the extension end 25a of the partition plate 25 that faces the heat exchange wall 21 in the plate height direction and the recess 21g.

[Effects of the embodiment]
With this configuration, the cooling fluid L flows linearly in the same direction in the multiple cooling flow paths F, thereby accelerating the flow rate of the cooling fluid L and improving the heat exchange efficiency of the cooling fluid L, thereby making it possible to efficiently remove heat from the battery B. In addition, since the cooling fluid L flows in parallel along the multiple cooling flow paths F, it is possible to suppress, for example, the inconvenience of the cooling fluid L stagnation near the side wall 23, and to uniformly remove heat from the battery B.

Because the leak-permitting portion C allows some of the cooling fluid L to leak between adjacent cooling flow paths F separated by the partition plate 25, even if the temperatures of the cooling fluid L flowing through adjacent cooling flow paths F are different, the temperature difference between the cooling fluid L flowing through adjacent cooling flow paths F is reduced by the leakage of the cooling fluid L, making it possible to more uniformly remove heat from the batteries B that are in contact with the outer surface of the heat exchange wall 21 in the width direction.

In addition, one end of the partition plate 25 in the plate height direction is welded to the bottom wall 22, and the other end in the plate height direction is not welded, which reduces manufacturing costs.

The leak-permitting portion C creates a gap between the inner surface of the heat exchange wall 21 and the extending end 25a of the partition plate 25. For this reason, the extending end 25a of the partition plate 25 is disposed in a groove-shaped recess 21g between a pair of guide portions 21a, which suppresses misalignment of the partition plate 25 while also allowing the cooling fluid L to actively leak between adjacent cooling flow paths F.

Furthermore, the upstream end plate thickness T1 of the multiple partition plates 25, which is the upstream end of the flow of the cooling fluid L, is set to be thicker than the downstream end plate thickness T2, which is the downstream end. As a result, the flow path width of the multiple cooling flow paths F is wider downstream than upstream, and the heat exchange area that removes heat from the battery B downstream of the cooling flow paths F is wider than the heat exchange area that removes heat from the battery B upstream of each of the multiple cooling flow paths F.

Therefore, when the cooling fluid L flows from the upstream side to the downstream side, the amount of heat that the cooling fluid L removes from the battery B is suppressed on the upstream side, and the temperature of the cooling fluid L that flows in contact with the inner surface of the heat exchange wall 21 is not significantly increased. In addition, when the cooling fluid L reaches the downstream side from the upstream side, the downstream side can remove heat from the battery B with a wider heat exchange surface than the upstream side, so the temperature difference between the battery B on the upstream and downstream sides of the heat exchange wall 21 is reduced, making it possible to equalize the temperature of each battery B.

[Another embodiment]
The present invention may be configured as follows in addition to the above-described embodiment (common numbers and symbols as in the embodiment are used to designate components having the same functions as in the embodiment).

(a) As shown in FIG. 6, the configuration of the leak-permitting portion C is such that the extending end 25a of the partition plate 25 is inclined toward the base end side (bottom wall 22 side) of the partition plate 25 so that the distance between the end (extending end 25a) closest to the heat exchange wall 21 in the plate height direction and the heat exchange wall 21 increases toward the downstream side in the flow direction of the cooling fluid L. This increases the amount of leakage of the cooling fluid L between the cooling flow paths F at the position sandwiching the partition plate 25 toward the downstream side of the multiple cooling flow paths F.

(b) As a configuration of the leak-permitting portion C, as shown in FIG. 7, a plurality of cutout portions 21b are formed by cutting out a part of the protruding end (lower side in FIG. 7) of the guide portion 21a of the heat exchange wall 21 on the downstream side in the flow direction of the cooling fluid L. This allows an increase in the amount of leakage of the cooling fluid L between the cooling flow paths F at a position sandwiching the partition plate 25 on the downstream side of the plurality of cooling flow paths F.

(c) As a configuration of the leak-permitting portion C, a through hole is formed in a part of the partition plate 25 on the downstream side of the multiple cooling flow paths F. This allows the cooling fluid L to leak through the through hole between the cooling flow paths F at a position sandwiching the partition plate 25 on the downstream side of the multiple cooling flow paths F. It is also possible to enlarge the diameter of the through hole the further downstream in the flow direction of the cooling fluid L.

It is assumed that the temperature of the cooling fluid L has risen to a certain degree downstream of the cooling flow path F, and the heat of the battery B cannot be efficiently removed. In contrast, by increasing the amount of leakage of the cooling fluid L between the cooling flow paths F at the position where the partition plate 25 is sandwiched downstream of the cooling flow path F as in the alternative embodiments (a), (b), and (c), for example, even in a situation where the temperature of the cooling fluid L flowing through some of the cooling flow paths F rises, the temperature difference in the width direction of the heat exchange wall 21 downstream in the flow direction of the cooling fluid L is reduced, enabling efficient cooling. As a result, the heat exchange efficiency of the cooling fluid L can be increased downstream of the cooling flow path F, which is prone to high temperatures.

(d) The heat sink A for cooling a battery may have multiple configurations each having an inlet section 1, a cooling main body section 2, and an outlet section 3, and multiple cooling main body sections 2 may be distributed and arranged on the bottom and side surfaces of the battery B, or multiple cooling main body sections 2 may be arranged in three locations: on the bottom surface and a pair of side surfaces of the battery B.

(e) In the above-described embodiment, a gap is provided between the heat exchange wall 21 and the partition plate 25, but a gap may also be provided between the bottom wall 22 of the cooling main body 2 and the partition plate 25. In this case, the heat exchange wall 21 and the partition plate 25 are welded and fixed by laser welding or the like. Also, the partition plate 25 is provided so that the cooling fluid L flows linearly in the same direction in the multiple cooling flow paths F, but the partition plate 25 may be provided so that the multiple cooling flow paths F meander.

(f) When a fluid such as hydrofluorocarbon (HFC) or hydrofluoroolefin (HFO) is used as the cooling fluid L, the property of changing from a liquid phase to a gas phase by removing heat from the battery B is utilized, enabling efficient cooling by latent heat.

The configurations disclosed in the above embodiment (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided no contradictions arise. Furthermore, the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these embodiments. Appropriate modifications can be made without departing from the scope of the present invention.

The present invention can be used in heat sinks for cooling batteries.

Reference Signs List 1 Inlet section 2 Cooling body section 3 Discharge section 21 Heat exchange wall 21g Recess 22 Bottom wall 25 Partition plate C Leak allowance section F Cooling flow path L Cooling fluid

Claims (5)

the cooling fluid is supplied from the inlet portion to the cooling body portion, and the cooling fluid is supplied from the inlet portion to the cooling body portion to remove heat from the battery; and the cooling fluid is supplied from the inlet portion to the cooling body portion to the cooling body portion.
the cooling body includes a partition plate that divides a region in a width direction perpendicular to a flow direction of the cooling fluid into a plurality of regions to form a plurality of cooling flow paths,
The cooling body has a leak allowing portion that allows leakage of the cooling fluid between adjacent cooling flow paths sandwiching the partition plate. The heat sink for cooling a battery according to claim 1, wherein the cooling fluid flows in the same direction in the multiple cooling flow paths divided by the partition plate in the cooling main body. The thickness of each of the partition plates is thinner on a downstream side of the cooling flow passage than on an upstream side of the cooling flow passage,
3 . The heat sink for cooling a battery according to claim 1 , wherein a width of the cooling flow passage on a downstream side is set wider than a width of the cooling flow passage on an upstream side in a parallel direction in which the plurality of cooling flow passages are arranged. the cooling body has a heat exchange wall adjacent to the battery and a bottom wall facing the heat exchange wall;
The heat sink for cooling a battery as described in claim 1 or 2, wherein one end of the partition plate in the plate height direction corresponding to the space between the heat exchange wall and the bottom wall is connected and fixed without any gaps to the inner surface of the bottom wall, and the other end of the partition plate in the plate height direction is supported in a form that creates a gap on the inner surface of the heat exchange wall as the leak tolerance portion. The battery cooling heat sink according to claim 4, wherein one end of the partition plate in the plate height direction is fixed to the bottom wall by welding, and the other end of the partition plate is disposed inside a recess formed in the heat exchange wall.

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