Battery module

Abstract

The present invention describes a battery module comprising: an array of battery cells electrically coupled for providing power to a load; a cell space containing an array of battery cells, the cell space being arranged to receive a coolant fluid flowing through the battery cells; the battery cell is mounted on a base of the cell space, the base comprising one or more flow paths for a coolant fluid; one or more inlets for receiving coolant flowing into one of the cell space or the susceptor; one or more outlets for the coolant to flow out of the other of the cell space or the base; and one or more fluid flow couplings between the cell space and the base for directing a flow of a coolant fluid between the base and the cell space. The inlet, the outlet, and the fluid coupling may be arranged to provide counter flow cooling such that a flow of coolant in the base is opposite a flow direction of coolant in the cell space.

Description

TECHNICAL FIELD

[0001] The present invention relates to a battery module, and in particular to a battery module having an array of battery cells cooled by a fluid coolant. BACKGROUND

[0002] In vehicles, watercraft, small aircraft and other modes of transportation, as well as industrial applications such as mining vehicles and equipment, the power system commonly used to provide motive power consists of one or more battery modules. The flexibility of such systems also makes them attractive as mobile power sources for home and industrial use. One of the challenges faced by such battery-powered power systems is how to maintain the battery cells within an optimal operating temperature range. The optimal temperature range varies depending on the chemistry of the cells. Thus, for some chemistries and application scenarios, the cells can need to be heated, while more commonly the cells need to be cooled. Overheated batteries age more quickly than batteries that are optimally cooled, which reduces the range, power and efficiency of the vehicle. In extreme cases, overheated batteries can also present safety issues.

[0003] Attempts have been made to air cool battery cells, but as the demand for battery modules has increased, liquid cooling systems have emerged. However, existing liquid cooling systems have problems providing optimal cooling to all of the cells. It would be desirable to address these problems and limitations of the prior art. SUMMARY

[0004] The present invention provides a battery module in which an array of battery cells is cooled by a fluid coolant flowing through a base beneath the cells, and by coolant flowing through a cell space in which the cells are at least partially immersed, in generally opposite directions.

[0005] Accordingly, the present application provides a battery module comprising: an array of battery cells electrically coupled for providing electrical power to a load; a cell space housing the array of battery cells, the cell space being arranged for receiving a flow of coolant fluid through the battery cells; a base on which the battery cells are disposed or mounted, the base comprising one or more flow paths for the coolant fluid; one or more inlets for receiving coolant flowing into one of the cell space or the base; one or more outlets for allowing coolant to flow out of the other of the cell space or the base; one or more fluid flow couplings between the cell space and the base for directing the flow of coolant fluid between the base and the cell space. Preferably, the base cooling and the cooling of the at least partially submerged cells are counter-current to each other. For example, the same coolant fluid can flow through the base of the battery cells in a first general direction, and then through the (at least partially) submerged cells in the cell space in a second general direction, which is, for example, opposite to the first direction. The cell space can be formed in one housing or one or more components of a housing, and can be sealed around the (at least partially submerged) battery cells. The cell space can be a sealed cell space housing the array of battery cells.

[0006] The one or more inlets, the one or more outlets, and the one or more fluid couplings can be arranged to provide counter-current cooling. For example, the inlets and the one or more fluid couplings can be arranged at opposite ends of one of the base or the cell space, and provide a first general flow direction, while the one or more fluid couplings and the outlets can be arranged at opposite ends of the other of the base or the cell space, and provide a second general flow direction.

[0007] The one or more inlets and the one or more outlets can be arranged at the same end of the battery module, for example adjacent to each other.

[0008] The ends of the battery cells in the array of battery cells can extend outside the cell space, the ends of the battery cells including vents for releasing gas from the cells. The ends of the battery cells that are outside the cell space can be the tops (or end caps) of the cells, or the base. The electrodes at the tops of the battery cells can likewise extend outside the cell space, or be electrically sealed or insulated within the cell space, the electrodes being electrically connected to each other for providing electrical power to the load.

[0009] The one or more flow paths of the base can be located below the battery cells, for example, to provide axial cooling.

[0010] The one or more fluid flow couplings between the cell space and the base can be arranged for: directing coolant flow from the base to the cell space; or directing coolant flow from the cell space to the base.

[0011] The cell space and the base can form different chambers, each having one or more flow paths.

[0012] The one or more flow paths in the base can be unidirectional or multidirectional, such as serpentine.

[0013] The base can be formed by a plate sandwiched in a housing. The housing can form at least the base of the cell space. There can be one or more flow paths between the plate and the housing for the coolant fluid.

[0014] One or more ridges can be arranged on the plate and / or the housing to provide one or more flow paths in the base.

[0015] The one or more fluid flow couplings can include one or more liquid inlets or openings, such as into the housing. The one or more liquid inlets or openings can be arranged for coupling fluid between the base and the cell space. These couplings can be integrated in the battery module.

[0016] The one or more liquid inlets or openings can be arranged in an array at an end of the cell space and the base distal to the end having one or more inlets and one or more outlets. That is, the one or more liquid inlets or openings are oriented towards the opposite end of the cell space and the base compared to the end having one or more inlets and outlets.

[0017] The array of one or more liquid inlets or openings at the end of the cell space can be distributed across the cell space in a direction transverse to the overall coolant flow direction.

[0018] The one or more fluid flow couplings can include a plumbing or interface having one or more conduits, such as a delivery manifold, connected to the base and the cell space to couple fluid between the base and the cell space. In this arrangement, the coupling can be considered to be external to the base plate and / or the module housing.

[0019] The battery module can further include one or more mid-position injectors, which are one or more liquid inlets or openings arranged in an array at a mid-position of the cell space and the base between the end having one or more inlets and the end having one or more outlets. For example, the mid-position injectors can be arranged at approximately half the flow path within the base or the cell space.

[0020] The battery cells can be cylindrical, and the battery module can include one or more baffles arranged at an edge of the array of battery cells, such as along a wall of the cell space. The one or more baffles can have a scalloped shape to equalize the space between the edge of the array of battery cells and the wall of the cell space.

[0021] The battery module can also include a plurality of conduits converging at one or more of the outlets. For example, the plurality of conduits fan out to receive coolant fluid from the battery array at a plurality of distribution locations.

[0022] The battery module can include an upper cell holder and / or a lower cell holder. The tops of the battery cells of the battery cell array can protrude through the upper cell holder. The upper cell holder can include a top plate. The bottoms of the battery cells of the battery cell array can be located on or within the lower cell holder, and the upper cell holder and the lower cell holder can hold the battery cells in place in the array.

[0023] The present disclosure also provides a battery module system including a battery module as described herein, a heat exchanger for cooling the coolant fluid, and a coolant pump. The heat exchanger can be connected to supply coolant fluid cooled by the heat exchanger to the battery module and to receive heated coolant fluid from the battery module for cooling. The pump can be arranged to repeatedly circulate fluid coolant between the base and the cell space to achieve base cooling and immersion cooling, respectively. The battery module system can include a plurality of battery modules electrically connected in series or in parallel, for example forming a battery pack. The plurality of battery modules can be thermally connected in series or in parallel, for example, a coolant flow path can distribute coolant between the modules or flow coolant from one module to another in series.

[0024] The heat exchanger and the coolant pump can be arranged to flow cooled coolant fluid to the base of the battery module and to receive heated coolant fluid from the cell space.

[0025] The battery module system can be configured to provide a coolant flow rate of 1-10 liters per minute, for example 2-4 liters per minute.

[0026] The battery module system can have a heat dissipation of 0.1 to 2 kW, and an average heat transfer coefficient of the coolant of 5-300 W / m 2 / K.

[0027] The present disclosure also provides a battery module comprising: an array of battery cells electrically coupled to provide power to a load; a cell space housing the array of battery cells, the cell space arranged to receive a coolant fluid flowing through the battery cells; a base on which the battery cells are disposed or mounted, the base comprising one or more flow paths for the coolant fluid; one or more first coolant inlets to receive coolant flowing into the base and one or more first outlets to allow coolant to flow out of the base; and one or more second coolant inlets to receive coolant flowing into the cell space and one or more second outlets to allow coolant to flow out of the cell space. The battery module can be included in a battery module system that also includes a first heat exchanger, a first coolant pump, and a second heat exchanger and a second coolant pump, wherein the first heat exchanger and the first coolant pump are connected in a first flow circuit to provide and receive coolant fluid to and from the cell space, and the second heat exchanger and the second coolant pump are connected in a second flow circuit to provide and receive coolant fluid to and from the base of the battery module. Different types of coolant can be used in the first coolant circuit (including the first heat exchanger and the first coolant pump) compared to the second coolant circuit (including the second heat exchanger and the second coolant pump). For example, the coolant used for one flow circuit can be a dielectric fluid, while the coolant used for the other circuit can be water.

[0028] The one or more inlets, the one or more outlets, and the one or more fluid couplings can be arranged to flow coolant in the base in a direction opposite to the flow of coolant in the cell space.

[0029] The present disclosure also provides a battery module comprising: an array of battery cells; a sealed cell space in which a portion of each cell is housed, the sealed cell space arranged to receive a coolant fluid flowing through the battery cells, and each battery cell mounted within a top plate that seals around the cell to retain fluid in the cell space, a first end of each cell extending from the sealed cell space and having a vent for releasing gas from the cell. The first end can be an end cap or a base of the cell. Electrode connection points, which are electrically coupled to provide power to a load, can also extend outside the cell space, or can be electrically sealed or insulated within the cell space. The top plate can be part of a module housing or an upper battery deck. This arrangement can provide immersion cooling, featuring the same as the above-described combined base-immersion cooling, but without the base cooling features. BRIEF DESCRIPTION OF DRAWINGS

[0030] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0031] Figure 1A perspective view of a battery module configured for fluid cooling;

[0032] Figure 2 A perspective view of a battery module configured for fluid cooling, Figure 1 An exploded perspective view of a battery module;

[0033] Figure 3 A perspective view of a battery module configured for fluid cooling, Figure 1 A cross-sectional view of a battery module;

[0034] Figure 4a , Figure 4b and Figure 4c Schematic diagrams showing embodiments of flow paths through a battery module, Figure 4a showing a counterflow with integrated coupling, Figure 4b showing a counterflow with external coupling, Figure 4c showing another arrangement where coolant flows through the base and cell space in a counterflow manner, but without a communicating flow path;

[0035] Figures 5a-5c Perspective and plan CFD images of base cooling only, immersion cooling only, and a combination of base and immersion cooling, respectively;

[0036] Figure 6a , Figure 6b and Figure 6c Plan views of three base coolant flow path layouts;

[0037] Figure 7 Plan view of a cell space showing shaping or baffling along the cell space length (top insert and center) and bottom coupling or opening for receiving coolant fluid from the base (bottom insert and center);

[0038] Figure 8a and Figure 8b Plan and perspective views of an outlet manifold for directing coolant fluid flowing through the cell space to an outlet, respectively; and

[0039] Figure 9 Schematic block diagram of a battery module 100 with cooling system. DETAILED DESCRIPTION

[0040] Figure 1 A perspective view of a battery module 100 configured for fluid cooling, Figure 2 An exploded perspective view of a battery module 100. As shown in Figure 1 and Figure 2 , the battery module includes a plurality of battery cells 130 arranged in an array in a cell space of the battery module. The battery module 100 includes an inlet and an outlet for flowing coolant fluid through the battery module. A base having a flow path is formed below the cell space.Figure 1 and Figure 2 One or more fluid flow couplings between the base and the cell space are not shown in Figure 1 Battery cell contacts 150 that connect the battery cells together and bus bars 154a, 154b that are used to output power to a load are also shown. A battery module or cell monitoring unit 152 can also be seen.

[0041] Referring to Figure 2 we now describe various elements of the battery module of Figure 2 . Starting with the base in the figure, we see that the battery module includes a base plate 110 and a housing 120. The base plate 110 can be a flat plate type structure. The housing 120 can be a cast or machined tray-like component with sidewalls and a floor. Figure 3 A cross section of the battery module is shown in Figure 1 of the portion labeled "A" in Figure 3 . The base plate 110 is also shown in Figure 3 . The base plate 110 and the recesses 121 together form a base with channels that form flow paths therein. The base plate 110 and the housing 120 can also include tabs or extensions 113, 123 that extend from the basic outline of the component (e.g. a rectangular outline). The tab 113 of the base plate can be an extension of the plate. The tab 123 of the housing includes a continuation of the recesses 121 on its underside. An inlet, such as an inlet stub 102 or conduit, can be provided on the top side of the tab. One sidewall of the housing 120 can also include an outlet, such as an outlet stub 104 or conduit. The outlet is preferably arranged in the sidewall proximate to the inlet, such that the inlet and outlet are provided on the same side or face of the housing 120. In this way, coolant can be easily provided and returned from a chiller or heat exchanger to cool the coolant fluid. Other arrangements of the base plate 110 and / or the housing 120 are possible in which a base with flow channels is provided.

[0042] Figure 2A lower cell holder 122 is also shown, in which the battery cells 130 are held. The cell holder can be formed of a polymer, such as a thermoplastic polyurethane (TPU). The cell holder 122 can be molded with a plurality of recesses for accommodating the bases of a plurality of battery cells 130. The cells 130 can be cylindrical cells arranged in an array. The cells can be of the 21700 cell type, but other types can also be used. The cells can be secured in the lower cell holder by an adhesive 124, or a thermal interface material (TIM) can be used to provide good thermal contact with the cell bases. In the drawing, an upper cell holder 140 is shown above the cells 130. The upper cell holder holds the upper portions of the battery cells 130 and has holes through which portions of the cells protrude above the cell holder. The upper cell holder 140 can be arranged so that the size of the holes is such that the tops of the cylindrical cells protrude through or sit in the holes. The vents at the tops of the cells 130 are exposed to the environment so that they can vent gas from the cells. The electrodes at the tops of the cells also protrude through the holes. The upper cell holder seals the cells or seals around the cells, for example by an adhesive or sealant. Alternatively, a top plate can seal the cells or seal around the cells to seal and enclose the cell space. Laminated busbars 150 provide electrical contact to the cells. The cells are preferably arranged in a combination of series and parallel connections. For example, referring to Figure 2 , the cells can be connected in series in the shorter width direction of the battery module, connected by the first and second electrode arrays of the laminated busbars. The cells connected in series in rows are then connected in parallel by the other electrodes of the laminated busbars 150. The connections from the cells to the series busbars can be made by welding to the positive and negative terminals of the cells. In some embodiments, the metal packaging shell or casing of the cells can form a negative or ground terminal to which the negative electrode can be welded.

[0043] At the top of the battery module 100 are the main busbars 154a and 154b. These busbars connect the various other positive and negative connection busbars and provide the main electrical connection from the battery module to the load. Figure 2 Also shown in the middle is a cell monitoring unit (CMU) assembly 152, which can include, for example, sensors for monitoring one or more physical parameters of the cells, such as voltage, current, and temperature. The drawing also shows a number of fixings, such as screws, for assembling and combining the battery module.

[0044] As mentioned previously, Figure 3 is shown Figure 1A schematic cross-section of the battery module 100 is shown. The housing 120 and the base plate 110 together form a base that includes a flow path for coolant to flow through. Other configurations can be used to form a base with a flow path. For example, the base plate can be formed from sandwiched plates with ridges in between to provide spacing for the flow path. The sandwiched plates of the base plate can then be attached to a housing with sidewalls and can or can not include a floor. Other alternative configurations for providing a flow path in the base are possible. Figure 3 Battery cells 130 are also shown arranged in the battery module. The battery cells appear to be different sizes, but this is not the case. The cross-section is taken in one plane that shows one series of battery rows to be a larger portion of the other series of battery rows. As shown, the bottom or lower portion of the battery cells are in contact with or close to the base or floor of the housing such that the bottom of the cells are cooled by the coolant fluid flowing through the recesses 121 in the base or base plate.

[0045] Figure 4a Figure 4b and Figure 4c are schematic diagrams showing different embodiments of the flow path through the battery module 100. For Figure 4a the flow path can be summarized as a counterflow with integrated coupling. In more detail, one or more flow paths 202 are provided in the base of the battery module and the cell space 204. The cell space 204 provides one or more flow paths around the battery cells that are at least partially immersed in the coolant fluid in the cell space 204. The fluid inlet and outlet of the battery module are provided adjacent to one another such that the coolant fluid can be easily circulated through a heat exchanger or chiller and back to the battery module. In Figure 4a the arrangement, the coolant fluid first flows through the base to provide base cooling and then through the cell space to provide immersion cooling. The base cooling and immersion cooling are counterflowed with one another. As we will explain and demonstrate later, through the counterflow dual cooling method, improved and more uniform cooling of the array of battery cells can be achieved. As Figure 4a shown, the coupling from the base to the cell space is integrated within the battery module. The coupling can be achieved through one or more holes or openings in the base that allow the coolant fluid to flow from the base to the cell space. The arrangement of the one or more holes or openings will be further discussed in connection with FIG. 6. While we have described the coolant to first flow to the base for base cooling and then to the cell space for immersion cooling, this can be reversed such that the coolant first flows to the cell space and then to the base.

[0046] Figure 4b ​Another cooling arrangement is shown in which the coupling between the base and the cell space is achieved through an external component or interface, such as a tubing or manifold. For example, the tubing or manifold can allow greater design control over where the coolant fluid enters the cell space in the vertical direction. In Figure 4a embodiments, the coolant fluid enters from the bottom of the cell space, while in Figure 4b the coolant fluid can enter the cell space at about half way up the cell space. The external component that is the coupling can be one or more tubes or manifolds. Manifolds can be conveniently used for multiple coupling flow paths. In Figure 4a and Figure 4b there is a single cooling loop as the coolant fluid returns to a single heat exchanger or chiller.

[0047] Figure 4c Another alternative embodiment is shown in which coolant fluid flows through the base and the cell space but without a connecting counterflow path. The cell space and base can be on separate cooling loops. For example, a dual cooling loop can be provided in which a first cooling loop has coolant fluid flow through the base and a first heat exchanger and a second cooling loop has coolant fluid flow through the cell space and a second heat exchanger.

[0048] For all of the embodiments shown in Figure 4a , Figure 4b and Figure 4c a number of such battery modules can be required to provide sufficient power for automotive and the like applications. When multiple battery modules are required, for the arrangements of Figure 4a and Figure 4b the coolant loops can be connected in parallel with a single heat exchanger so that each battery module is uniformly cooled. Alternatively, if the number of battery modules is small, each module can be provided with its own heat exchanger and cooling loop. A combination of the two can also be used. For the embodiments of Figure 4c there are various possible arrangements of the cooling loops. For example, the arrangement of the cooling loops can be similar to Figure 4b . Alternatively, multiple battery modules can be connected together with the coolant first flowing through the bases of all the modules and then through the cell spaces of each module. In this arrangement, the coolant can flow through the module bases in parallel and then through the cell spaces in series or in parallel. Other series or parallel cooling arrangements for the bases and cell spaces can be used. Furthermore, depending on the cooling requirements of the particular application, some modules can be preferentially cooled over others. Implementations Figure 4cAnother option for embodiments of the application is to use two heat exchangers and cooling loops, one for the base and the other for the cell space of one or more battery modules. In this arrangement, different coolant fluids can be used for the two cooling loops. Water can be used for the base cooling, while a dielectric fluid can be used for the cell space. In all of these arrangements, counterflow of the coolant fluids between the base and the cell space is preferred.

[0049] Figures 5a-5c are thermal plots showing the improved cooling effect of combined base cooling and immersion cooling counterflow compared to base cooling only and immersion cooling only. These are simulation results, with an initial coolant inlet temperature of 50 °C and a heat dissipation of 0.53 W per cell in each case. In each figure, lighter areas represent cooler areas, and darker areas represent hotter areas. Each figure includes a perspective view showing the thermal distribution from the top to the bottom of the cells. The plan view and the perspective view in each figure show the heat distribution in the planar area of the battery module. In Figure 5a and Figure 5c the inlet and outlet are adjacent, but in Figure 5b the inlet and outlet are on opposite sides of the battery module.

[0050] Figure 5a shows the thermal distribution of a battery module using base cooling only. The flow path is a serpentine configuration of the battery module base. The serpentine flow is intended to provide balanced cooling throughout the module. In the perspective view, the battery cells in the corners of the module closest to the inlet and outlet are the coolest. This can also be seen in the plan view. The lower half of the battery cells in the corners near the inlet and outlet are also cooler than the top of the battery cells. However, base cooling alone is not very effective, with a large amount of dark shading indicating that a large portion, if not the entire, battery module is not being cooled well. Figure 5a the temperature range from coolest to hottest in

[0051] Figure 5b shows the thermal distribution of a battery module using immersion cooling only. The flow is directed from one side of the battery module, the inlet side, directly to the other side of the battery module, the outlet side. In Figure 5b the perspective view shows less variation from top to bottom of the battery cells. The cooling is also more effective than Figure 5a the base cooling. Many of the battery cells are well cooled, but as the coolant fluid temperature increases, the cooling near the outlet side weakens. The coolant flow is also poor at the corner of the outlet side, resulting in these corners being the hottest. The temperature range throughout the battery module is from about 50 °C near the inlet to about 54 °C at the corner of the outlet side. Thus, this arrangement of immersion cooling can be considered effective, but not balanced.

[0052] Figure 5cA thermal profile of a battery module employing a combination of base cooling and immersion cooling in a counterflow configuration is shown as Figure 2 and Figure 4a described. The coolant fluid enters the inlet and first flows through the base plate along a straight flow path to the other end of the battery module. The base cools the cells on the left side of the diagram first. After the base cooling, the coolant fluid is fed into the cell space via a series of openings or holes. The immersed cells are then cooled, and the coolant flows through the cell space in the opposite direction of the flow in the base. The thermal map shows that the counterflow combination cooling is effective for balanced cooling of the entire battery module. Figure 5c In the thermal map, the temperature range from the coldest to the hottest is about 50°C to 52°C. This is only a two-degree Celsius change. Balanced cooling is achieved at the inlet / outlet end of the battery module, which receives the coldest and hottest coolant since it receives the coldest coolant from the heat exchanger to the base, and also receives coolant that is heated by passing through most of the remaining portion of the battery module base and cell space. Figure 5c The right side of the battery module in the thermal map receives partially heated coolant and heats further. Thus, balanced cooling of the battery module is achieved.

[0053] Figure 5c The inset diagram shows a battery cell. Cooling of the battery cell can be considered radial or axial, and different cooling directions can have different thermal conductivities. For base cooling, the cooling is only axial. Thus, Figure 5a The arrangement of the base cooling has only axial cooling. For immersion cooling, the cooling is radial. Thus, Figure 5b The arrangement of the immersion cooling has only radial cooling. For Figure 5c The combination of base cooling and immersion cooling of the battery module of The combination of base cooling and immersion cooling of the battery module of

[0054] The combination of base cooling and immersion cooling of the battery module of Figure 6a , Figure 6b and Figure 6c show embodiments of base coolant flow path layouts. Regarding Figure 2 we describe a base consisting of a base plate 110 and a housing 120 with a flow path that causes coolant to flow from one end of the base to the other end. Figure 6a , Figure 6b and Figure 6c the layout shown can be considered a view of the channels machined or manufactured under the floor side of the housing 120, although as previously mentioned, other ways of manufacturing the channels are possible.

[0055] Figure 6a show a battery module with a combination of base cooling and immersion cooling in a counterflow configuration. Figure 5cuniform one-way arrangement of the simulation results. The inlet is provided on a tab or extension, where the coolant flows into the base. A series of ridges 304 are shown, which are left by machining away the recesses 306 of the base. The ridges are straight and extend along a substantial portion of the length of the base. For example, greater than 70% of the length of the internal flow cavity in the housing, such as about 80%. There is a distribution region at each end, which allows the coolant entering the flow space to split between the different flow paths provided by the ridges, and re-mix at the other end from the different flow paths. In Figure 6a embodiments, the ridges are straight and extend along a substantial portion of the length of the base. For example, greater than 70% of the length of the internal flow cavity in the housing, such as about 80%. There is a distribution region at each end, which allows the coolant entering the flow space to split between the different flow paths provided by the ridges, and re-mix at the other end from the different flow paths. In Figure 6a embodiments, five channels are shown, but other numbers of channels can be provided. Figure 6a One or more openings or holes are also shown, for coupling the coolant fluid into the space above the cells. In Figure 6a embodiments, six openings are shown, each comprising a hole, such as a circular hole. The size of the holes will be a factor in determining the speed of coolant flow through the base. The holes are evenly distributed across the width of the base, but the first and last holes can be introduced from the edges. Other numbers of holes, shapes of holes, and layouts of holes are possible. The geometry of the flow path controls the transition of the coolant fluid from the inlet to the immersed cell space.

[0056] Figure 6b Another scheme for the flow path in the base is shown. In this arrangement, a single flow path is provided with a serpentine path. The recess is machined to form a series of ridges extending transversely across the general flow direction. The ridges extend alternately from one side and then the other, leaving a gap at one end for the coolant to flow into the next part of the serpentine. In Figure 6b embodiments, the serpentine comprises eight changes of direction, two to the left and two to the right (from the inlet). Other numbers of changes of direction can be provided. Each end of the base comprises a space to allow the coolant fluid to flow into the desired region. At the inlet end, the coolant is spread across the width of the flow path. At the end of the coupling / hole close to the cell space, the distribution region is larger than Figure 6a the region at the inlet end, to allow the coolant fluid to spread evenly across the array of holes. A smaller distribution region can cause more flow through the holes closest to the end of the serpentine.

[0057] Figure 6c Another alternative flow scheme is shown. This scheme is similar to Figure 6a but allows for some variation in the flow direction. As with Figure 6aIn contrast, six unidirectional flow paths are included, rather than five. From the inlet, the flow paths in the middle of the base are wider than the flow paths at the edges. Also, the flow paths are separated by ridges. The outer ridges and flow paths extend to 70% or 80% of the length of the base. The center flow paths also have ridges, but these ridges are broken in the middle region. In this middle region, an array of another hole or opening 308 is provided for injecting coolant fluid from the base into the cell space. The breaking of the ridges provides a middle distribution region to allow five holes or openings 308 to be distributed in the space of four flow paths. Other numbers of middle region injector holes 308 and flow paths can be included, but by including a middle distribution region, more or fewer holes than the number of flow paths can be provided. In other embodiments, more arrays of holes or openings to the cell space can be included, such as a first array along one third of the length of the base, a second array along two thirds of the length of the base, and a third array at the end of the base.

[0058] Figure 7 、 Figure 8a and Figure 8b shows features of the cell space where cooling of the battery cells is by immersion cooling. Figure 7 shows the coupling or opening on the cell space floor or base for coolant fluid to flow from the base into the cell space (see center figure and lower inset). Figure 7 Also shown are baffles at the edge of the array (see center figure, upper inset, and line drawing). As shown, the couplings 302 can be aligned with the battery cell array. For example, the battery cells can be arranged in a hexagonal array with six battery cells at the vertices of the hexagon and a seventh cell positioned in the center of the hexagon. This configuration can be repeated throughout the array. The couplings or openings can be positioned to correspond to the positions of the battery cell array, but the position does not include a cell. Thus, as shown, six couplings or openings are included that align with the rows of battery cells in the array. This position provides a convenient and space-saving location for the openings. The geometry is integral with the floor of the housing. The openings control the transition of coolant fluid from the base to the immersion cavity. The number, size, and location of the openings or couplings can be different than shown. Figure 7 Figure 7

[0059] Figure 7 ​​A shaped portion or baffle is also shown disposed along the length of the cell space or long side corresponding to the general flow direction. The shape of the baffle controls the flow at the periphery of the cell space to balance the flow at the edge regions. Depending on the clearance to the cell, a simple rectangular or straight edge of the cell space can either promote or substantially block the flow at the edge. In the former case, excessive flow at the edge means reduced flow between the battery cells, reducing the cooling effect. In the latter case, blocking the flow at the edge can mean that the cells at the edge are not effectively cooled. The baffle or shaped portion at the edge of the cell space corresponds to the profile shape of the cell array. The shaped portion can therefore be a scalloped shape 310 comprising a series of circular arcs which can be centred on the battery cells at the end of the array but slightly larger than the battery cells. The spacing between the battery cells at the edge of the array and the baffle is preferably similar to the minimum spacing between the battery cells in the array. The addition of the baffle makes the flow rate at the edge of the array of battery cells substantially equal to the flow rate between the battery cells in the array. In embodiments where the cooling requirements at the edge of the array can be different to the array, the spacing between the baffle and the cells can be greater or less than the spacing in the array to make the temperature at the edge of the array equal to the temperature in the array.

[0060] Figure 8a and Figure 8b An outlet manifold 402 is shown configured to direct and collect the coolant fluid through the cell space as it moves to the outlet. Figure 8a A plan view of the outlet manifold, Figure 8b A perspective view of the outlet manifold. The battery cells are removed in both figures. The manifold can be integrally formed as part of the housing. The manifold comprises a plurality of ducts 404 which collect the coolant fluid from the entire width of the cell space to direct the coolant fluid to the outlet, for example to the outlet stub 104. In Figure 8a and Figure 8b In the plan view, from the outlet, the six ducts are spaced across the width of the cell space, fanning out from the outlet. The outer two ducts are angled to the general flow direction to direct the coolant fluid out from the edge of the cell space. The central four ducts are aligned to the general flow direction into the cell space. The ducts from one side of the cell space combine into a first main duct 405 connected to the outlet and the ducts from the other side of the cell space combine into a second main duct connected to the outlet. The outer ducts connect to one of the main ducts which can be aligned transverse to the general flow direction. The central four ducts connect to one of the main ducts at an angle of approximately 90°. Each duct extends from the top to the bottom of the cell space. The outlet stub can be configured to receive a tubing, for example a rubber or plastic tubing, for flowing the fluid coolant in a cooling circuit.

[0061] Figure 9is a schematic block diagram of a battery module 100 with a cooling system. The battery module 100 is connected at its coolant fluid outlet to a pump that circulates coolant fluid through the coolant system. Coolant from the pump enters a heat exchanger, which for automotive applications can be a radiator. The hot coolant passes through the radiator or heat exchanger 510 and cools. If a radiator is used, a fan can force ambient air through the radiator to cool the coolant. The cooled coolant exits the radiator or heat exchanger, flowing back to the battery module to cool the cells therein. As described above with respect to the embodiments of Figure 4c Other cooling systems including multiple cooling loops can be used.

[0062] In one embodiment of the invention, the battery cells are 21700 type cylindrical cells arranged in a 14S24P configuration. That is, the cells are arranged in 14 rows connected in series, with 14 cells in each row connected in parallel with the 14 cells of the other rows. There are 24 rows of cells connected in parallel, for a total of 336 cells. Other numbers and arrangements of cells are possible. As can be seen in the various figures, the rows of cells can not have the cells arranged in a straight line, but can be arranged in a zigzag or offset arrangement to match a hexagon-based array arrangement. The 21700 type cells are a lithium ion battery cell, typically designated as 21700 NMC to indicate a nickel, manganese, and cobalt cathode. The nominal output voltage of the 21700 type cell is approximately 3.7V, with a maximum of 4.2V when fully charged. The array of 336 cells provides an output of 35.0 to 58.8V, with a total energy capacity of 5.1 kWh. A battery module including these cells and arranged as in the embodiments described herein can have a length of approximately 670 mm, a width of approximately 330 mm, and a height of approximately 90-100 mm. The dry mass of the battery module is approximately 35 kg. The cooling medium of the battery module is preferably a dielectric fluid so as to effectively act as an insulator between the cells. For the embodiments shown in Figure 4a and Figure 6a The volume or capacity of the base for the embodiments shown is 2 to 4 liters, for example 2.5 to 3.0 liters, typically 2.9 liters. The cell space with immersion cooling has a much smaller coolant volume, for example less than 1 liter, for example less than 0.5 liters, typically 0.3 liters. Thus, the total typical coolant volume of the battery module can be 3.2 liters. The flow rate through the battery module can be 1-5 liters / minute, for example 2.5 to 3.5 liters / minute, and typically 2.9 liters / minute. In the arrangement shown, the total immersion volume of the cells is 5.7 liters, and the surface area of the base cooling cells is 0.2 m 2 . The total immersed cell surface area can be 1.1 m 2 .

[0063] Although specific embodiments of the application have been described in reference to the attached figures, those skilled in the art will recognize that changes and modifications can be made to these embodiments without departing from the scope of the application as defined by the claims. For example, although the embodiments shown in the figures include one inlet and one outlet, other numbers of inlets and outlets can be provided.

[0064] Another variation can be the use of different cell formats and arrangements. We have described that the top of the cell can extend outside of the sealed cell space to allow for gas to be vented from the cell and to connect to the electrical connections of the cell. In alternative embodiments, the connection to the electrical connections of the cell can be achieved in the sealed cell space, the electrical connections and the connection being sealed or insulated in the cell space.

[0065] Furthermore, in one embodiment, immersion cooling can be achieved without the need for base cooling. In this case, the coupling would be replaced by one or more inlets located at the opposite end of the cell space from the one or more outlets.

Claims

1. A battery module, comprising: A battery cell array, electrically coupled to provide power to a load; A cell space that accommodates the array of battery cells, the cell space being arranged to receive coolant fluid flowing through the battery cells; The battery cell is mounted on a base in the cell space, the base including one or more flow paths for the coolant fluid; One or more inlets for receiving coolant flowing into one of the cell spaces or the base; One or more outlets for allowing the coolant to flow out from the cell space or another in the base; One or more fluid flow couplings are located between the cell space and the base for guiding the flow of coolant fluid between the base and the cell space.

2. The battery module according to claim 1, wherein, The one or more inlets, the one or more outlets, and the one or more fluid couplings are arranged to provide countercurrent cooling, such that the flow of coolant in the base is opposite to the flow of coolant in the cell space.

3. The battery module according to claim 1 or 2, wherein, The one or more inlets and the one or more outlets are arranged at the same end of the module.

4. The battery module according to any one of the preceding claims, wherein, The top of the battery cells in the battery cell array extends outside the cell space, and the top of the battery cells includes vents for releasing gas from the cells.

5. The battery module according to any one of the preceding claims, wherein, The top of the battery cells in the battery cell array extends outside the cell space, and the electrodes at the top of the battery cells are electrically connected to supply power to the load.

6. The battery module according to any one of the preceding claims, wherein, One or more flow paths of the base are located below the battery cell.

7. The battery module according to any one of the preceding claims, wherein, One or more fluid flow couplings between the cell space and the base are arranged for: Guide the coolant to flow from the base to the cell space; or The coolant is guided to flow from the cell space to the base.

8. The battery module according to any one of the preceding claims, wherein, The cell space and the base form different chambers, each chamber having one or more flow paths.

9. The battery module according to any one of the preceding claims, wherein, One or more flow paths in the base are unidirectional or serpentine.

10. The battery module according to any one of the preceding claims, wherein, The base is formed by a plate sandwiched in a housing, the housing at least forming the base of the cell space, and there are one or more flow paths between the plate and the housing for the coolant fluid.

11. The battery module according to claim 10, wherein, One or more ridges are arranged on the plate and / or the housing to provide one or more flow paths in the base.

12. The battery module according to any one of the preceding claims, wherein, The one or more fluid flow coupling portions include one or more inlet holes or openings, which are arranged to couple fluid between the base and the cell space.

13. The battery module according to claim 12, wherein, The one or more inlet holes or openings are arranged in an array at the ends of the cell space and the base, the ends being located at the distal ends of the ends having the one or more inlets and one or more outlets.

14. The battery module according to claim 12, wherein, An array of one or more inlet holes or openings located at the end of the cell space is distributed in the cell space in a direction transverse to the overall coolant flow direction.

15. The battery module according to any one of claims 1 to 11, wherein, The one or more fluid flow couplings include a piping system or interface having one or more conduits connected to the base and the cell space to couple fluid between the base and the cell space.

16. The battery module according to any one of the preceding claims further includes one or more intermediate position injectors, said one or more intermediate position injectors being one or more liquid inlets or openings arranged in an array at an intermediate position between the cell space and the base, located between an end having one or more inlets and an end having one or more outlets.

17. The battery module according to any one of the preceding claims, wherein, The battery cell is cylindrical, and the battery module includes one or more baffles arranged at the edge of the cell space. The one or more baffles have a serrated shape to balance the space between the edge of the battery cell array and the wall of the cell space.

18. The battery module according to any one of the preceding claims further includes a plurality of converging pipes at one of the one or more outlets, the plurality of pipes fanning out to receive coolant fluid from the battery array at a plurality of distribution locations.

19. The battery module according to any one of the preceding claims, comprising an upper battery holder and a lower battery holder, wherein the top of the battery cells of the battery cell array protrudes through the upper battery holder, the bottom of the battery cells of the battery cell array is located on or inside the lower battery holder, and the upper battery holder and the lower battery holder hold the battery cells in proper position in the array.

20. A battery module system comprising a battery module as described in any of the preceding claims, a heat exchanger for cooling a coolant fluid, and a coolant pump, wherein, The heat exchanger is connected to supply coolant fluid cooled by the heat exchanger to the battery module and to receive heated coolant fluid from the battery module for cooling.

21. The battery module system according to claim 20, wherein, The heat exchanger and coolant pump are arranged to allow the cooled coolant fluid to flow to the base of the battery module and to receive the heated coolant fluid from the cell space.

22. The battery module system of claim 20 or 21, configured to provide a coolant flow rate of 1-10 liters per minute, for example 2-4 liters per minute.

23. A battery module, comprising: A battery cell array, electrically coupled to provide power to a load; A cell space that accommodates the array of battery cells, the cell space being arranged to receive coolant fluid flowing through the battery cells; The battery cell is disposed or mounted on a base in the cell space, the base including one or more flow paths for coolant fluid; One or more first coolant inlets for receiving coolant flowing into the base, and one or more first outlets for allowing the coolant to flow out of the base; as well as One or more second coolant inlets for receiving coolant flowing into the cell space, and one or more second outlets for allowing the coolant to flow out of the cell space.

24. A battery module system comprising a battery module according to claim 23, a first heat exchanger and a first coolant pump, and a second heat exchanger and a second coolant pump, wherein, The first heat exchanger and the first coolant pump are connected in a first flow loop to provide coolant fluid to and receive coolant fluid from the cell space, and the second heat exchanger and the second coolant pump are connected in a second flow loop to provide coolant fluid to and receive coolant fluid from the base of the battery module.

25. The battery module system according to claim 24, wherein, The inlet and outlet are arranged such that the coolant flows in the base in a direction opposite to the flow of the coolant in the cell space.

26. A battery module comprising: Battery cell array; A sealed cell space, a portion of each cell is housed within the sealed cell space, and the sealed cell space is arranged to receive coolant fluid flowing through the battery cell. Each battery cell is mounted inside a top plate that seals around the cell to retain fluid within the cell space. A first end of each cell extends from the sealed cell space and has a vent for releasing gas from the cell.

27. The battery module according to claim 26, wherein, Each cell, extending from the sealed cell space, also includes an electrode connection point at its first end that is electrically coupled to provide power to a load.

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