Battery cell support for battery module

Abstract

Described is among other things a battery cell support for a plurality of battery cells comprising a support (30, 32) comprising a plurality of cavities (31) Each cavity is shaped to receive and hold a battery cell (20) in a fixed position, and wherein connectors are provided in the support.

Description

[0001] Battery cell support for battery module

[0002] Technical field

[0003] The present invention relates to a battery module. In particular the present invention relates to a battery cell support and a battery cell support assembly suitable for use in a battery module optimized for liquid immersion cooling of battery cells, and to a battery module.

[0004] Background

[0005] There is an increased use of heat generating devices such as electric components and rechargeable batteries. Applications include for example, energy storage, energy transformation to powering electric equipment and vehicles or as a power back up in stationary applications. During operation, the heat generating components generate heat which needs to be dissipated effectively to allow safe functioning of the components and prevent failure of the module in which such heat generating components are housed. The performance of the heat generating component is to a large extent limited by the available thermal management techniques for keeping the component within an appropriate temperature range.

[0006] In for example battery applications, it is known to have thermal management systems employed within the battery module to control the operational temperature of the battery cells within an optimal temperature range.

[0007] Increased energy storage capacity and reduced charging times have led to a strive for more efficient thermal management in general, and dissipation of generated heat in particular. One commonly employed thermal management method is known as immersion cooling, which also referred to as liquid submersion cooling. This is the practice of submerging components, such as e.g., battery cells, in a thermally conductive but electrically isolating liquid. Thus, the heat may be transferred directly from the heat source, e.g., battery cell, electronics, printed circuit board, to the working fluid and dissipated through a heat exchanger located elsewhere.With the ever-increasing performance requirements regarding storage capacity and strive for more space efficient systems, there is a need for improved and more efficient thermal management techniques and production of systems for thermal management.

[0008] There is a constant desire to improve the efficiency of batteries and the cost for production of batteries. Hence there is a need for an improved battery and battery module.

[0009] Summary

[0010] It is an object of the present invention to at least partly overcome the above problems, and to provide an improved battery module with liquid cooling. In particular a liquid cooled battery module where the battery cells of the battery are immersed in the liquid.

[0011] This object and I or other is obtained by the battery cell support, the battery cell support assembly and the battery module as set out in the appended claims.

[0012] In accordance with the invention a battery cell support for a plurality of battery cells is provided. The battery cell support comprises a support comprising a plurality of cavities, each cavity shaped to receive and hold a battery cell in a fixed position. The battery cell support comprises a plurality of connections for connecting a restricting member. Hereby a battery cell support assembly can be easily assembled that has restricting members in the spaces between the individual battery cells of a battery. The connectors can advantageously be formed by cavities or a projection in the structure between the cavities. Hereby restricting members provided with a projection (or a cavity) can simply be inserted into the cavities to provide a fast assembly of the battery support assembly.

[0013] In accordance with some embodiments, flow channels can be provided in the support, the flow channels extend from a top side of the support to a bottom side of the support.Hereby an increased flow can be provided in a battery module when the battery cell support ids used to hold battery cells in an immersed battery module.

[0014] In accordance with some embodiments at least some, and in particular all, flow channels are arranged along the side walls of the cavities. Hereby the increased flow will be led along the sides of the battery cells, thereby increasing heat transfer from the battery cells to the circulating liquid.

[0015] In accordance with one embodiment, the flow channels have a semi-circular cross section as seen in the direction from the topside of the battery cell support. Hereby heat transfer from the battery cells can be improved.

[0016] In accordance with one embodiment, the number of cavities can advantageously be 10 or more for one single support and the battery cell support can formed as one monolithic structure for example as a plastics mould.

[0017] In accordance with one embodiment, the battery cell support comprises a plurality of connections for connecting a restricting member. Hereby a battery cell support assembly can be easily assembled that has restricting members in the spaces between the individual battery cells of a battery. The connectors can advantageously be formed by holes in the structure between the cavities. Hereby the restricting members can simply be inserted into the holes to provide a fast assembly.

[0018] The invention also extends to a battery cell support assembly comprising two battery cell supports, at least one of the battery cell supports being a battery cell support according to the above and where the two battery cell supports are interconnected by restricting members.

[0019] The invention further extends to a battery module comprising a battery, the battery comprising a number of battery cells, the battery cells being fixed by a battery cell support according to the above or a battery cell support assembly according to the above where the restricting members are located between the battery cells.Brief

[0020]

[0021] of the

[0022]

[0023] The invention will now be explained more closely by the description of different embodiments of the invention and with reference to the appended figures.

[0024] Fig. 1 schematically illustrates a battery module in accordance with a first embodiment, Fig. 2 schematically illustrates a part of a battery module in accordance with a second embodiment,

[0025] Fig. 3 is a view in perspective of a battery,

[0026] Fig. 4 is a bottom view of a battery,

[0027] Fig. 5 illustrates a battery cell support assembly in a disassembled state,

[0028] Fig. 6 illustrates a battery cell support assembly,

[0029] Fig. 7 shows the support assembly in a side view, and

[0030] Fig. 8, shows the support assembly in a cress-sectional view.

[0031] Detailed

[0032]

[0033] Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. It is to be understood that the drawings illustrate exemplary embodiments and that components can be added or omitted from the shown embodiments to meet specific implementation needs. Like numbers in the drawings refer to like elements throughout the description.

[0034] In Fig. 1, a battery module 10 is depicted. The battery module 10 comprises a battery 12 located in a liquid tight container 14. The battery 12 can for example be formed by a single or multiple battery cells to form a battery pack such as round or prismatic battery cells. Between the battery cells is a space where a liquid can flow freely. The battery can be of different types, for example lithium, zinc, sodium -based. Also including LFP, NMC, LTO as well as from second life battery modules or packs.

[0035] The battery module further comprises a liquid 18. The liquid 18 is used for temperature control of the battery 12. The liquid 18 can in accordance with some embodiments becirculated inside liquid tight container 14. The liquid 18 can advantageously be a dielectric liquid. The battery cells of the battery are typically immersed in the liquid 18.

[0036] In order for the liquid 18 to circulate inside the liquid tight container 14, a pump can be provided or the liquid 18 can circulate by natural convection. Thus, the flow inside the liquid tight container 14 can be driven by Buoyancy convection. Buoyancy-driven convection denotes a type of heat transfer in a fluid, in which the fluid flow is driven solely by a density difference due to a temperature gradient in a volume and the acting gravity force, here the volume defined by the liquid tight container 14.

[0037] When the liquid is circulated, it can be advantageous to provide a space below the battery 12 such that the liquid can flow between individual battery cells to a space between the bottom side of the battery 12 and the bottom side of the liquid tight container 14. The space can be formed by locating spacers 16 on the inside of the bottom side of the liquid tight container 14.

[0038] The battery module 10 can comprise enlargements on its outer and / or inner walls. Hereby the surface of the battery module can be increased so as to increase the area for heat dissipation. This can improve the performance of the battery module 10. For example, fins 15 or similar enlargements can be provided on the outer surface of the liquid tight container 14. Enlargements can also be provided on the inside wall of the liquid tight container 14. For example, inner enlargements such as projections can be formed on the inside wall of the liquid tight container 14.

[0039] Further, enlargements on the outer and / or inner wall also improves a Buoyancy driven flow of the liquid inside the liquid tight container by introducing a larger density difference between hot and cold liquid inside the liquid tight container 14.

[0040] In Fig. 2, a battery module 10 in accordance with another embodiment is depicted. The battery module 10 in the embodiment shown in Fig. 2 is similar to the embodimentshown in Fig.1. In the embodiment of Fig. 2, the battery module comprises flow control plate(s) 27 on one or more of the sides of the battery 12. The flow control plates are arranged in a direction from the bottom to the top of the liquid tight container 14. Hereby, flow circulation can be improved. Cold liquid will go in a downwards direction at the outside of the flow control plate as indicated by the arrow and warm liquid will go upwards also indicated by arrows.

[0041] The flow control plate 27 can be formed by a vertical plate as seen in in Fig. 2 along the side of the battery 12. The flow control plate 27 can also have an inclined top section 27a to enhance circulation. As a result, more flow (and heat) is forced in an upwards direction whereby more heat is driven to the top side of the liquid tight container 14 so as to increase the convection since the temperature difference between the top side and the bottom side of the liquid tight container will be increased. Also, cooling of the battery cells can be improved by controlling the flow in an upwards direction along the battery cells as seen in Fig. 2.

[0042] Further, an elastic member 28 can be placed inside the liquid tight container 14. The elastic member can for example be small blade springs. The elastic member configured to place a predetermined pressure to the battery 12, to keep the battery in place inside the liquid tight container. Thus, the elastic member 28 can act as a holder to hold the battery 12 by friction force.

[0043] Further, a spacer element 16 can be provided at the bottom of the battery 12. The spacer element provides for a more or less free flow of liquid in under the battery 12 such that liquid freely can flow from the bottom side of the liquid tight container 14 up in between individual battery cells of the battery 12.

[0044] In accordance with some embodiments the liquid tight container 14 is filled with a liquid, but for a relatively small volume, such that a small volume about 10 % or even less is unfilled. By not filling the volume completely thermal expansion can be handled. In accordance with some other embodiment, the liquid tight module is completely filled with liquid, in such an embodiment, some kind of expansion device is advantageously provided. The expansion device can be any device allowing for thermal expansion of the liquid. The expansion device can be external to the liquid tight container. Inaccordance with some embodiments, the expansion device is placed inside the liquid tight container. In such an embodiment, the expansion device can be a compressible member such as a rubber body or a partially gas filled bag or some other member suitable for allowing for thermal expansion / contraction of the liquid inside the liquid tight container 14.

[0045] In Fig. 3, a view in perspective of a battery 12 is depicted. The battery 12 is made up of a number of battery cells 20, The battery cells 20 can be of different types. In this exemplary embodiment, the battery cells are of prism type. The battery cells 20 are fixed in a support 30. The support 30 can advantageously be set to fix the battery cells 20 at the lower or bottom part of the battery cells 20. In addition, a second support 32 can be provided to fix the battery cells 20 of the battery 12. In the embodiment shown in Fig. 3, the battery cells 20 are fixed at the bottom part thereof by the support 30 and at the top part of the battery cells 20 by the second support 32.

[0046] The supports 30, 32 fixing the battery cells 20 at its bottom and top part can be identical.

[0047] In Fig. 4, a bottom view of the battery 12 of Fig. 3 is shown. When the supports 30 and 32 are identical a top view of the battery 12 would be similar. The support 30 is a single structure configured to hold and fix a plurality of battery cells 20. The support can be formed as a moulded plastics structure as one monolithic part. The support can have cavities sized to receive individual battery cells 12. The number of cavities can be large, typically 10 or more cavities can be formed in one single support. In accordance with some embodiments the cavities are formed as holes in particular through holes. In accordance with other embodiments, the support has a bottom part onto which the battery cells can rest when placed in the support 30. The support can advantageously be formed as a grid with walls delimiting the cavities. The support 30 has channels 35 formed therein. The channels extend from the top part of the support 30 to the bottom part of the battery module 10 such that a fluid in the can flow through the support from top to bottom of the battery module. The channels can have a suitable shape such assemi-circular cross section. The cross section can also be rectangular, triangular circular or have some other shape. Thus, the support 30 will have cavities formed therein. The side surfaces delimiting the cavities in the support 30 will typically have channels formed therein.

[0048] It can be advantageous to locate the channels 35 such that the channels are in direct contact with a battery cell placed in the support as is shown in Fig. 4. Hereby cooling of the battery cells 20 can be increased in that the liquid 18 of the battery module 10 is in direct contact with the side surfaces of the battery cells 20 so as to increase heat transfer from the battery cells 20 to the liquid 18.

[0049] In Fig. 5, different parts of a support assembly 40 when disassembled is shown. The support assembly 40 comprises a bottom support 30 and a top support 32. In the embodiment of Fig. 5, the supports 30 and 32 are designed for cylindrical battery cells 12. The supports 30, 32 are shaped as grids having cavities 31 delimited by walls on the sides. The cavities 31 are formed on one surface, here termed cavity side 39, of the supports 30, 32. The cavities can in some embodiments be through holes through the supports 30, 32 as shown in Fig.5. The surface of the cavity side 39 can in some embodiments be generally flat.

[0050] The delimiting walls 33 are formed by the structure of the support 30, 32. The support assembly 40 can also comprise restricting members 36. Advantageously the restricting members 36 are pin shaped. The restricting members are configured to be located in the spaces between the battery cells when the battery cells are placed in the support assembly 40. The restricting members 36 can be connected to the support 30 and 32 via connectors. The connectors are typically formed on the cavity side 39. In the embodiment shown in Fig. 5 this is the topside surface of the lower support 30 and on the bottom side surface of the upper support 32. The connectors can for example be a groove 37 in the support 30. The groove 37 can cooperate with a corresponding projection 38 in the restricting member 36 for assembly of the support assembly 40. Other types of connectors can be envisaged such as a snap fit or similar. In another embodiment the connectors can be a projection in the support 30, 32 that cooperateswith a corresponding groove in the restricting member 36. In one exemplary embodiment one of the supports 30, 32 has a connector formed as grooves whereas the other support 30, 32 has a connector formed as a projection. In such an embodiment, the restricting member 36 will have a projection in one end and a groove in the opposite end. Hereby an easy assembly of the support assembly can be obtained. The restricting members 36 can serve to better distribute liquid in the battery module as described in PCT / SE2022 / 050435.

[0051] The grooves 37 and the projections 38 can have a generally polygonal shape in a cross section in the plane of the cavity surface 39. In particular the grooves 37 and projections 38 can have a generally triangular cross section in the plane of the surface of the support 30 as seen in Fig. 5. However other shapes can be envisaged such as circular or oval cross sections.

[0052] In Fig. 6, the support assembly 40 is shown in a perspective view when assembled.

[0053] In Fig 7, the support assembly 40 is shown in a side view.

[0054] In Fig. 8, the support assembly 40 is shown in a cress-sectional view along the line A-A in Fig 7. In Fig. 8, the restricting members 36 are shaped with a generally triangular cross section in the cross section shown in Fig. 8 (i.e. in a plane perpendicular the direction in which the pin shaped restricting member extends). This can be particularly advantageous when the battery cells are cylindrical. The restricting members 36 act to reduce the area of the channel formed between the battery cells. The restricting members can have curved side walls to better match with the battery cells. This is particularly so when the battery cells are cylindrically shaped. Depending on the application the restricting members 36 can be pin shaped with a suitable cross-sectional shape such as triangular or round, in particular circular. The restricting members can be made from a material compatible with the dielectric fluid in the liquid tight container. For example, the restricting members 36 can be made of a plastics material, a ceramic material, textile material, metal material or similar.

Claims

Claims1. A battery cell support for a plurality of battery cells comprising:a support (30, 32) comprising a plurality of cavities (31) formed at a cavity side (39) of the support, each cavity shaped to receive and hold a battery cell (20) in a fixed position, and wherein the battery cell support comprises a plurality of connections (37) on the cavity side (39) for connecting a restricting member (36).

2. The battery cell support according to claim 1, wherein flow channels (35) are provided in the support, the flow channels extending from a top side of the support to a bottom side of the support.

3. The battery cell support according to claim 2, wherein at least some flow channels (35) are arranged along the side walls (33) of the cavities.

4. The battery cell support according to claim 3, wherein all flow channels are arranged along the side walls of the cavities.

5. The battery cell support according to claim 3 - 4, wherein the flow channels have a semi-circular cross section as seen in the direction from the topside of the battery cell support.

6. The battery cell support according to any one of claims 1 - 5, wherein the number of cavities is 10 or more.

7. The battery cell support according to any one of claims 1 - 6, wherein the battery cell support (30, 32) is formed as one monolithic structure.

8. The battery cell support according to any one of claims 1 - 7, wherein the connectors are formed by grooves (37) and I or projections on the surface of the support between the cavities.

9. The battery cell support according to claim 8, wherein the grooves (37) and / or projections have a polygonal cross section in the plane of the surface of the support (30) on which the connectors are formed.

10. A battery cell support assembly (40) comprising two battery cell supports (30, 32), at least one of the battery cell supports being a battery cell support according to any one of claims 1 -9, and where the two battery cell supports are interconnected by restricting members (36) connected to the connectors of the battery cell supports (30, 32).

11. The battery cell support assembly (40) according to claim 10, wherein the restricting members (36) are pin shaped.

12. The battery cell support assembly (40) according to claim 11, wherein the restricting members (36) have a generally triangular cross section in a plane perpendicular to the direction in which the restricting members extend.

13. The battery cell support assembly (40) according to claim 12, wherein the restricting members have curved side walls.

14. A battery module (10) comprising a liquid tight container (14), a battery (12) immersed in a liquid, the battery comprising a number of battery cells (20), the battery cells being fixed by a battery cell support (30, 32) according to claim 1 - 9 or a battery cell support assembly (40) according to any of claims 10 - 13 where the restricting members (36) are located between the battery cells (20).

Images