Immersion module

Abstract

Described is among other things an immersion module (100). The immersion module can provide for more even cooling and dense packing of heat generation components (160) such as batteries.

Description

[0001] Immersion module

[0002] Technical field

[0003] The present invention relates to a temperature regulated module and devices related thereto. In particular the present invention relates to an immersion module for temperature control of heat generating components and arrangements used for immersion heat control of heat generating components in particular battery cells.

[0004] Background

[0005] The rapid advancement of climate friendly energy sources, fossil-free metal production, electric vehicles (EVs), and other battery-powered technologies has led to an increased demand for efficient and reliable battery modules. Critical challenges in battery module design are managing the heat generated during operation as well the cold surrounding in wintertime. Excessive heat or too low temperature can degrade battery performance, reduce lifespan, and pose safety risks.

[0006] A rapidly growing application area is efficient energy storage, for example to electricity grid support for more helping global transition to more the sustainable and climate friendly energy. Therefore, effective cooling methods are essential to maintain optimal battery performance and ensure safety.

[0007] Several approaches have been developed to cool battery cells within a module:

[0008] Air Cooling: This method involves circulating air around the battery cells to dissipate heat. While air cooling is relatively simple and cost-effective, it may not be sufficient for high-power applications due to its limited heat transfer capability.

[0009] Phase Change Materials (PCMs): PCMs absorb heat as they change from solid to liquid, providing a passive cooling solution. These materials can be integrated into the battery module to absorb excess heat during operation and release it slowly over time. PCMs are particularly useful for managing temperature spikes and maintaining a stable thermal environment. Heat Pipes: Heat pipes are highly efficient thermal conductors that transfer heat through the evaporation and condensation of a working fluid. They can be embedded within the battery module to rapidly transport heat away from the cells to a heat sink or external cooling system.

[0010] Thermal Management Systems (TMS): Advanced TMS combine multiple cooling methods, such as liquid cooling and heat pipes, with active control mechanisms to optimize thermal performance. These systems can dynamically adjust cooling based on real-time temperature data, ensuring efficient heat dissipation under varying operating conditions.

[0011] Liquid Cooling: Liquid cooling systems use a coolant, such as water or a glycol mixture, to absorb and transfer heat away from the battery cells. This method offers higher thermal conductivity compared to air cooling and is more effective for high- power applications. Liquid cooling can be implemented using cooling plates, tubes, or jackets that are in in-direct contact with the battery cells.

[0012] One particular type of liquid cooling is so called immersion cooling. In immersion cooling heat generating components such as battery cells are submerged in an electrically isolating liquid, which efficiently dissipates heat generated during operation. Thus, the heat generating components are submerged in a dielectric fluid. This fluid directly contacts the battery cells, providing heat transfer that typically exceeds traditional air or liquid cooling systems that rely on indirect contact through cooling plates or channels. The dielectric fluid used is electrically highly non-conductive, ensuring that it does not interfere with the electrical components of the battery.

[0013] Further, there are generally three major battery cell constructions cylindrical, prismatic and pouch cells. These constructions pose different problems related to thermal control. In the cylindrical cell the active battery cell material is contained inside a cylindrical enclosure that is mechanically stable and does not allow any expansion. In the prismatic cell the battery material is contained inside a rectangular enclosure and during charge / dis-charge cycles the active cell material will expand and increase the volume of the cell.

[0014] In the pouch cell the enclosure is soft and the active cell material is almost free to expand.

[0015] The expansion of the battery cell has a negative impact on electrical performance and life-time of the battery cell. It is therefore common practice to pre-load battery constructions with prismatic or pouch cells. The pre-load arrangement aims to counteract the expansion thus increase electrical performance and life-time. Pre-load constructions generally work on the largest surface of the battery cell and cells are pressed against each other. Thus, the major surface area of the cell become unavailable to heat transfer.

[0016] For prismatic and pouch battery cells, the pre-load construction is a major problem with immersion cooling designs because the major area of the battery cell will not be available for direct heat transfer to the cooling liquid.

[0017] There is a constant desire to improve efficiency, size and cost of immersion cooled modules and to thereby increase the performance of the heat generating components housed inside the module. Hence there is a need for an improved immersion cooled module and in particular an immersion cooled battery module.

[0018] It is an object of the present invention to at least partly overcome the above problems, and to provide an improved module with immersion cooling. In particular an immersion cooled battery module

[0019] This object and I or other is obtained by the immerse cooled battery module as set out in the appended claims. In accordance with the invention, an immersion module configured for thermal control of heat generating components is provided the immersion module comprises a liquid tight casing configured to withhold a non-pressurized liquid. The liquid tight casing comprises a top section a bottom section and a plurality of side walls. A plurality of heat generating components are located side by side inside the liquid tight casing. At least some of the heat generating components are laterally separated by distance members such that vertical flow channels are formed from the top of the heat generating component to the bottom of the heat generating components. The vertical flow channels provide flow paths along the sides of at least some of the heat generating components. The immersion module further comprises a flow restrictor configured to restrict the flow in at least one of the flow channels. Hereby an even flow for all flow channels can be provided whereby even cooling of a plurality of heat generating components can be obtained.

[0020] In accordance with some embodiments the immersion module comprises a top space between the top of the heat generating components and the top section, and a bottom space between the bottom of the heat generating components and the bottom section. Hereby an immersion module with an external pump can be provided.

[0021] In accordance with some embodiments, the immersion module comprises two compartments. Hereby the liquid can be pumped within the immersion cooled module by an internal pump.

[0022] In accordance with one embodiment, the flow restrictor is a flow distribution plate located at the bottom side of the heat generating components where the flow distribution plate comprises holes at the lower end of the flow channels. Hereby an easy to implement flow restrictor can be provided. The holes have can different sizes and different number of holes can be provided at different flow channel ends. Hereby the flow restriction can be implemented in an easy manner.

[0023] In accordance with some embodiments, a distance member is located between at least some of the heat generating components, and wherein the flow channels are formed inside the distance member. The distance member can comprise two plates separated by vertical bars. Hereby flow channels can be formed by an element that also can serve to electrically isolate heat generating components. The distance members can also provide pre-loading. The plates can for example be made of aluminium. The plates can be separated by a distance of less than 3 mm.

[0024] In accordance with some embodiments, the distance member it-self can comprise a flow restrictor. For example, the flow channels inside the grid elements can have having different width to control the flow in individual flow channels.

[0025] In accordance with some embodiments, at least one liquid inlet at a first level of the liquid tight casing, and at least one liquid outlet at a second level of the liquid tight casing, the second level being lower than the first level. The at least one liquid inlet is provided in the top space, and said at least one liquid outlet is provided in the bottom space. Hereby an immersion module with an external pump can be easily implemented.

[0026] Brief description of the drawings

[0027] The invention will now be explained more closely by the description of different embodiments of the invention and with reference to the appended figures.

[0028] Fig. 1 illustrates a battery module in a perspective view.

[0029] Fig. 2 illustrates a battery module in a perspective view with the lid removed

[0030] Fig. 3 is similar to Fig. 2 with the batteries removed,

[0031] Fig. 4 is a detailed view of a part of Fig. 3,

[0032] Fig. 5 is a view of a distance member used in the battery module,

[0033] Fig. 6 is a schematic cross-sectional view of an immersion module in accordance with a first embodiment,

[0034] Fig. 7 illustrates a flow distribution plate in a top view,

[0035] Fig. 8 illustrates a flow distribution plate in a perspective view, and

[0036] Fig. 9 is a schematic cross-sectional view of an immersion module in accordance with a second embodiment, Detailed description

[0037] Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. In the following description a liquid cooled module with heat generating components is described. The heat generating components are in some of the exemplary embodiments set out to be battery cells. However, the heat generating components can be other types of heat generating components such as motors, electrical components, micro-processors, printed circuit boards etc. Like numbers in the drawings refer to like elements throughout.

[0038] While the below description is related to cooling heat generating components, it is also envisaged that the same set-up for thermal control can be used to heat cool components in a cool environment, such as in space applications and similar applications.

[0039] Figure 1 shows an example of an immersion cooled module 100 in a perspective view. The immersion cooled module 100 is designed to provide cooling for heat generating components. The heat generating components can typically be batteries, but can also be other types of heat generating components or thermal sensitive components. Such other types of heat generating components can comprise motors, electrical components, micro-processors, printed circuit boards and the like.

[0040] The immersion cooled module 100 has a liquid tight casing 110 wherein a liquid can be circulated to cool or heat the heat generating components located inside the immersion cooled module 100. The liquid tight casing comprises a top section 120, a bottom section 130 and a plurality of side walls 140. In the embodiment shown in Fig.1 , the casing is formed as a rectangular box with four side walls 140 and a flat top section 120 and a flat bottom section. However, the liquid tight casing 110 can have other geometrical shapes to meet specific implementational needs. For example, the liquid tight casing 110 can have three or more side walls 140.

[0041] The liquid tight casing 110 in accordance with the embodiment of Fig. 1 comprises a liquid inlet 151. The liquid inlet 151 can preferably be located at an upper position on one of the side walls 140. In particular the liquid inlet can be located at a level above an upper maximum liquid level inside liquid tight casing 110. The liquid tight casing 110 can further comprise a liquid outlet 152. The liquid outlet can be located at a level below the liquid inlet 151. In particular the liquid outlet can be provided at a level below heat generating components located inside the liquid tight container 110. The liquid inlet 151 and liquid outlet can in accordance with some embodiments be provided on the same side wall 140. Hereby easy connection of a pump (not shown) to pump a liquid from the liquid outlet 152 to the liquid inlet 151 can be implemented. Also, more than one liquid inlet 151 and or more than one liquid outlet 152 can be provided in accordance with some embodiments.

[0042] In Fig. 2 a view of the immersion cooled module 100 similar to Fig. 1 is shown. In Fig. 2 the top section 120 is removed such that the inside of the liquid tight casing 1 10 is visible in a perspective view. Inside the liquid tight casing 110 a plurality of heat generating components 160 are located. The heat generating components 160 can be arranged, at least partly, side by side inside the liquid tight casing 110. In the exemplary embodiment of Fig. 2, the heat generating components 160 are all located side by side in a plurality of rows. The heat generating components 160 in Fig. 2 are prismatic battery cells. The heat generating components 160 can however be some other type of battery cells such as based on other chemistry or different shape such as for example pouch or cy lindric types of battery cells, or some other type of heat generating component as set out above.

[0043] At least some of the heat generating components 160 can be separated by some distance member 165 to allow for a liquid to pass from the topside of a heat generating component between two heat generating components to a location under the heat generating components as will be described in more detail below. The distance member can also advantageously be designed to allow for pre-load mechanism generally needed for some types of cells such as prismatic and pouch cells.

[0044] Fig. 3 is similar to Fig. 2. Fig. 3 shows the immersion cooled module 100 with the heat generating components removed. The distance member(s) 165 are located to laterally separate, at least some, of the heat generating components such that vertical flow channels are formed from the top of a heat generating component to the bottom of the heat generating component. Distance members 165 that allows such a vertical flow from a top space between the top of the heat generating components and the top section to a bottom space between the bottom of the heat generating components and the bottom section can be shaped in various ways. In the embodiment shown in Fig. 3, a grid of distance members 165 is formed such that each heat generating component has a distance member 165 on all sides of the heat generating component or at least each side facing another heat generating component.

[0045] In Fig. 4 a detail of the grid of distance members 165 as illustrated in Fig. 3 is shown. The distance members 165 in the exemplary embodiment shown in Fig. 4 comprises two cooling plates 166 and 167, respectively. The two cooling plates 166 and 167 face each other and are separated by a plurality of vertical bars 169. The two cooling plates and a pair of vertical bars 169 forms a vertical flow channel 170 where a liquid can pass from the top side of the two cooling plates 166, 167 to the bottom side of the two cooling plates 166, 167.

[0046] The cooling plates 166, 167 in the embodiment of Fig. 4 can act to increase the cooling of heat generating components. The cooling plates 166, 167 can be configured to press against the sides of the heat generating components 160 as can be seen in Fig. 2. Hereby heat from the heat generating components can dissipate via the cooling plates 166, 167. The cooling plates are in turn cooled by the liquid flowing in the flow channels 170 inside the distance members 165.

[0047] The distance members 165 can also be formed in other ways. For example, the distance members can be formed in U-, S- or various meander shapes depending on the design constraints of the battery system. For example, in accordance with some embodiments the distance members 165 can be triangular or hexagonal in shape. A primary function of the distance member 165 is the separate different heat generating components so as to allow the liquid to flow between two different heat generating components. The flow can be designed with an optimum flow distribution and optimum flow rate.

[0048] The distance member can also serve to keep the battery cells, here prismatic cells, electrically isolated from each other in that the distance member can be made from an electrically isolating material. In accordance with some embodiments, the distance members 165 can also serve as a pre-load means for applying a pressure counter acting expansion of battery cells. The cooling plates as described herein can serve such a function as a distance member.

[0049] In Fig. 5, a view in perspective of a distance member 165 in accordance with the embodiments of Fig. 3 and 4 is shown. The distance member165 can for example be made of aluminium. The distance member 165 can also be made of some other heat conducting material including composite materials. The cooling plates 166, 167 can have a thickness of about 0.2 - 2 mm. the length and width are determined by the application. The two cooling plates 166, 167 are separated by bars 169. The bars can have a hight separating the two cooling plates of about 1 - 5 mm. The width of the bars 169 can be about 1 - 10 mm. The bars 169 can be separated by a suitable distance to form the flow channels 170. Thus, depending on the application, at least one flow channel 170 is formed. In a typical application the bars 169 can be separated by about 3 - 50 mm.

[0050] In Fig. 6 a simplified cross-sectional view of the immersion cooled module 100 is shown. In Fig. 6 a liquid is pumped into the immersion cooled module 100 via the liquid inlet 151. The liquid level 225 is preferably kept at a level above the heat generating components 160 and below the liquid inlet 151 or at least below the top section 120 such that the liquid inside the immersion cooled module 100 is not pressurized. Thus, the immersion cooled module needs to be liquid tight but not pressure tight.

[0051] The liquid flows in the flow channels 170 between the heat generating components 160 to a flow distribution plate 200. The flow distribution plate 200 will be described in more detail below. The liquid passes through the flow distribution plate to a space 223 formed between the flow distribution plate 200 and the bottom section 130. The space 223 can be formed by placing spaces 240 between the flow distribution plate 200 and the bottom section 130 as will be described in more detail below. The liquid can then exit the immersion cooled module 100 via the liquid outlet 152 and be cooled outside the liquid cooled module and then pumped back into the liquid cooled module 100 via a pump 500. In this embodiment, the pump is a pump external to the immersion cooled module. In Fig. 7, the flow distribution plate 200 is shown in a perspective view from above. The flow distribution plate 200 comprises at least one hole 210 at the end section of each flow channel 170. The holes are configured to even out the liquid flow in the plurality of flow channels. By providing an even flow in the different flow channels 170, cooling of the plurality of heat generating components 110 can be made even such that all heat generating components are cooled equally or at least close to equally within some predetermined variation. By allowing for an equal cooling, temperature variation in the immersion module can be kept low such as for example under 3 degrees C temperature variation between the battery cells or even less such as under 2 degrees C temperature variation. This low temperature variation helps to improve the life time of the battery system because the battery cells operate balanced. If, on the other hand, there would be a large difference in temperature then the cells will deteriorate differently meaning that some battery cells will deteriorate faster than others, The battery system as a whole depends on all battery cells, thus failure of the system may occur prematurely if the cells are not in good balance.

[0052] Also, all heat generating components will have similar environmental situation, thereby enabling higher power and faster charging without destroying the battery cells with less efficient cooling, as well as faster and easier balancing between battery cells.

[0053] The flow in the flow channels 170 is evened by the flow distribution plate in the flow in the flow channels are restricted in a controlled manner. The control of the flow is provided by configuring the area of the holes under each flow channel differently for different flow channels. For example, the number of holes or the size of the holes can be configured for each flow channel or as in the exemplary embodiment shown in Fig 5 a set of flow channels associated with a distance member 165.

[0054] Thus, the distance member(s) can be located between at least some of the heat generating components, and flow channels can be formed inside the distance member. Hereby flow channels can be formed by an element that also can serve to electrically isolate heat generating components. The distance members can also provide pre- loading. All of this is particularly useful when the heat generating components are battery cells. Thus, as shown in Fig. 7, holes 210 closer to where the liquid outlet is located provide more flow restriction than the holes 220 far away from the liquid outlet. Hereby the flow in all flow channels can be made more equal in that without the flow distribution plate 200 the flow resistance from the liquid inlet to the liquid outlet is larger for the flow paths further away from the liquid outlet in the configuration in accordance with Fig. 2.

[0055] The flow distribution plate thus acts as a flow restrictor configured to restrict the flow in at least one of the flow channels. In other words, by restricting the liquid flow in some flow channels 170 more than in other, the flow resistance can be equalized when the flow resistance is different for different flow channels 170. Hereby the liquid flow for each flow channel or set of flow channels can be equalized so as to better distribute the cooling over the entire immersion cooled module 100.

[0056] In accordance with some embodiments the liquid outlet 152 can be located at a level above the distribution plate 200. In such an embodiment an opening 215 can be provided in the distribution plate 200. The opening 215 thus serves to provide a flow path from under the distribution plate 200 to the liquid outlet 152.

[0057] The flow distribution plate 200 can be secured to the bottom section 130 by some fastening means. For example, screws can be applied in screw holes 220.

[0058] In Fig. 8, the flow distribution plate 200 is shown in perspective. As can be seen in Fig. 8, the flow distribution plate 200 can be provided with spacers 240 at its bottom side. The spacers 240 can act to form a space between the bottom side of the flow distribution plate 200 and the top side of the bottom section 130. In the space formed between the flow distribution plate 200 and the bottom section 130 the liquid circulated in the immersion cooled module 100 can flow back towards the liquid outlet.

[0059] In Fig. 9 an immersion cooled module 300 in accordance with a second embodiment is depicted in a schematic view. The second embodiment is similar to the embodiment shown in Fig. 6. In the immersion cooled module 300, the liquid is pumped within the immersion cooled module by a pump 600. The module 300 comprises two compartments 350, 370. A first heat release compartment 350 where the liquid is cooled by releasing heat to the outside of the immersion cooled module 300 and a second cooling compartment 370 where the liquid cools the heat generating components. The heat release compartment 350 can be provided with cooling flanges 355 or similar cooling means to increase the cooling of the liquid in the heat release compartment 350. In the embodiment of Fig. 9 the two compartments 350 and 370 are arranged side by side separated by a wall 360. However, the two compartments can also be configured in other configurations such as placing the second compartment 370 inside the first compartment.

[0060] In the embodiment shown in Fig. 9, the immersion cooled module 300 is completely filled with liquid. Also, in a configuration as shown in Fig. 9, the liquid flow inside the flow channels 170 can be from the bottom-up as indicated by the flow arrows in Fig. 9. In a configuration as shown in Fig. 9, it can be advantageous to provide the flow distribution plate 200 at the top side of the heat generating components. Hence, depending on the configuration of the immersion cooled module the flow distribution plate can be located either on top of or below the heat generating components or at the top end or bottom end of the flow channels 170.

[0061] The pump 600 of the immersion cooled module 300 can be any suitable pump such as a mechanic, electrostatic, electromagnetic, centrifugal, capillary, piezoelectric or acoustic pump. In accordance with some embodiments the pump is an ultrasound actuator. Using such an ultra sound actuator as pump can increase vibration in the liquid whereby heat transfer can be increase. In yet another embodiment, the pump 600 is supplemented by an ultrasound actuator 390 whereby both a high flow and ultra sound vibrations can be provided.

[0062] The exemplary embodiments described herein mainly describe an immersion cooled module. However, it is to be understood the that the module can also be an immersion heated module. Thus, the description should be understood to describe an immersion module. The module can be used both for heating and cooling of heat generating components depending on the application.

Claims

Claims1. A immersion module (100, 300) configured for thermal control of heat generating components (160), the immersion module comprising:- a liquid tight casing (110) configured to withhold a non-pressurized liquid, the liquid tight casing comprising a top section (120), a bottom section (130) and a plurality of side walls (140),- a plurality of heat generating components (160) located side by side inside the liquid tight casing, wherein at least some of the heat generating components are laterally separated by distance members (165) such that vertical flow channels (170) are formed from the top of the heat generating component to the bottom of the heat generating components, wherein the vertical flow channels provide flow paths between the top space and the bottom space, and the immersion module further comprising a flow restrictor (200) configured to restrict the flow in at least one of the flow channels.

2. The immersion module (100, 300) according to claim 1 , wherein the flow restrictor is a flow distribution plate (200) located at the bottom side of the heat generating components, the flow distribution plate comprising holes at the lower end of the flow channels.

3. The immersion module (100, 300) according to claim 2, wherein the holes (210, 220) of the flow distribution plate of the have different sizes.

4. The immersion module (100, 300) according to claim 2 or 3, wherein different number of holes (210, 220) in the flow distribution plate are provided at different flow channel ends.

5. The immersion module (100, 300) according to any one of claims 1 - 4, wherein a distance member is located between at least some of the heat generating components, and wherein the flow channels are formed inside the distance member.

6. The immersion module (100, 300) according to claim 5, wherein the distance member comprises two plates (166, 167) separated by vertical bars (169).

7. The immersion module (100, 300) according to claim 5 or 6, wherein the plates are made of aluminium.

8. The immersion module (100, 300) according to any one of claims 5 - 7, wherein the plates are separated by a distance of less than 3 mm.

9. The immersion module (100, 300) according to any one of claims 5 - 8, wherein the distance member comprises a flow restrictor.

10. The immersion module (100, 300) according to claim 9, wherein the flow restrictor in the distance member is formed by flow channels having different width.

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