Electric battery pack with battery cells in direct contact with a flow of a thermoregulating liquid, with optimised distribution of the thermoregulating liquid and porous separator panels between the cells

Abstract

An electric battery pack (100) comprises a plurality of battery cell stacks (101) arranged within a container (4). Each stack (101) includes an array of battery cells (2), arranged parallel to each other and spaced apart from each other, along a first horizontal direction (X). The stacks (101) are arranged in one or more rows parallel to each other along a second horizontal direction (Y) orthogonal to the first horizontal direction (X). The cells (2) of all the stacks (101) are in direct contact with a flow of a thermoregulating liquid which flows through the container (4), for the purpose of maintaining the battery pack within a specified temperature range. In each stack (101) the thermoregulating liquid flows from an inlet collector chamber (13A) that extends below the cells (2), through the spaces between the cells (2), and up to an outlet collector chamber (13B) above the cells (2). The cells (2) of each stack (101) are separated from each other by panels (30) made of porous material, for example consisting of one or more layers of a mesh made of stainless steel, or steel coated with an insulating layer, or one or more layers of a mesh made of polymeric material, preferably a superpolymer, for example PEEK. In one example, the porous panels (30) include rigid inserts (40) tending to prevent a swelling of the cells (2) during the use.

Description

[0001] “Electric battery pack with battery cells in direct contact with a flow of a thermoregulating liquid, with optimised distribution of the thermoregulating liquid and porous separator panels between the cells”

[0002] ****

[0003] Field of the invention

[0004] The present invention relates to an electric battery pack, of the type comprising:

[0005] - a container of the battery pack,

[0006] - a plurality of battery cell stacks arranged within the container of the battery pack and each including an array of battery cells,

[0007] - wherein the cells of each battery cell stack are arranged parallel to each other and spaced apart from each other, along a first horizontal direction,

[0008] - wherein the battery cell stacks are arranged in one or more rows parallel to each other along a second horizontal direction orthogonal to the first horizontal direction,

[0009] - wherein the battery cells of each pair of battery cells adjacent to each other have main surfaces facing each other, between which spacer elements are interposed, so as to define a space between the cells,

[0010] - wherein all the battery cells of all the battery cell stacks are in direct contact with a flow of a thermoregulating liquid which flows through the container of the battery pack, for the purpose of maintaining the battery pack within a specified temperature range.

[0011] Prior art

[0012] Electric battery packs having the above features have been known and used for some time.

[0013] Figures 1-4 of the attached drawings refer to a single battery module of a known type.

[0014] Figure 1 is a schematic perspective view of a known battery module, of the type provided with a thermoregulating system using a thermoregulating liquid in direct contact with the cells. The battery module of Figure 1 , indicated as a whole with the reference number 1 , includes a plurality of prismatic cells 2, arranged aligned along a direction X inside a container 4 and immersed in a flow of a thermoregulating liquid which flows through the container 4.

[0015] In this description, and in the attached drawings, the construction details relating to the supply circuit of the thermoregulating liquid and to the control of the temperature of the thermoregulating liquid are not illustrated, since they can be made in any known way and also since such details, taken separately, do not fall within the scope of the present invention. In general, the thermoregulating liquid supply system may include a pump to activate the circulation of the liquid and one or more heat exchangers to maintain the thermoregulating liquid at a desired temperature. The thermoregulating liquid (for example a dielectric oil) may perform both a cooling function, when the temperature of the battery module tends to exceed a predetermined maximum threshold value, and a refrigeration function, when the temperature of the battery module tends to fall below a predetermined minimum threshold value. The thermoregulating liquid supply system is preferably electronically controlled on the basis of signals emitted by one or more sensors arranged in the battery module. Again, all the above details are not illustrated here, both because they can be made in any known way, and because they do not fall, taken individually, within the scope of the invention, and also because their removal from the drawings makes the latter simpler and easier to understand.

[0016] Figure 2 is an enlarged perspective view of a prismatic battery cell 2, comprising an upper surface 2A, two opposite main surfaces 2B, which inside the container 4 are arranged orthogonally to the cell alignment direction X, two side walls 2c and a lower wall 2d. In the example illustrated in figure 2, the positive pole 3P and the negative pole 3N of the battery cell 2 protrude from the upper wall 2A. However, it is also possible that the two poles 3P, 3N, are arranged on one of the lateral faces 2C of the cell 2.

[0017] According to a technique known in itself, all the positive poles 3P and all the negative poles 3N of the cells 2 are electrically connected to each other and to the two respective poles P and N protruding, in the example illustrated, from an end wall of the container 4 (see figure 1 ).

[0018] Figure 3 is a schematic sectional view in the median vertical plane of the battery module of Figure 1 . With reference to this figure, the container 4 includes an inlet opening 5A for the thermoregulating liquid, communicating with an inlet collector chamber 5 arranged below the array of battery cells

[0019] 2. The container 4 also includes an outlet opening 6A for the thermoregulating liquid, communicating with an outlet collector chamber 6, arranged above the array of battery cells 2. Again with reference to figure

[0020] 3, the battery cells 2 are arranged spaced from each other in such a way as to define a plurality of spaces 7 which put the inlet collector chamber 5 in hydraulic communication with the outlet collector chamber 6. In general, this is achieved by interposing spacer frames between the cells. The set of spacer frame cells is held in an assembled condition by applying a compressive force along the longitudinal direction X (figure 1 ) by means of any known type, for example by tie rods (not illustrated). The size of the spaces 7 between the cells 2 has been exaggerated for clarity of figure 3. In practice, the distance between two adjacent cells may be for example in the order of a few millimeters (e.g. about 2 mm).

[0021] Figure 4 is a partially sectioned perspective view of a battery module of the known type described above, in which one of the cells 2 has been removed to illustrate a portion of a spacer frame, comprising a lower horizontal strip 8, which extends along the lower edge of a cell 2, across the width of the cell 2 (i.e. in the direction Y of figure 1 ).

[0022] Figure 5 illustrates a further example of a spacer frame 8, configured to be mounted astride each battery cell, including a plurality of vertical strips 80 intended to be arranged on the two sides of a cell, to separate the cell from adjacent cells.

[0023] Figure 6 of the attached drawings shows a battery pack of a known type, of the type including a plurality of battery modules 1 , each with its own container 4 having a respective input 5A for the thermoregulating liquid.

[0024] Figure 7 instead shows a solution in which multiple stacks 101 of battery cells 2 are arranged within a single container 4. A similar arrangement is also illustrated in the scheme in figure 8, which shows a battery pack 100 comprising a container 4 intended to be crossed by the flow of thermoregulating liquid, inside which multiple stacks of battery cells 101 are arranged, each including an array of battery cells 2. In figure 8, the spaces between the stacks 101 and the spaces between the stacks 101 and the container have been exaggerated for clarity. The battery cells 2 of each stack 101 are arranged aligned in the direction X shown in figure 6. The various stacks 101 are in turn arranged aligned along two rows in the direction Y of figure 8.

[0025] In known solutions such as those illustrated in figure 8, typically at the two opposite ends of the container 4 two additional spaces 9 are provided, both for safety reasons and to contain additional components, such as a pump 102 to activate the circulation of the thermoregulating liquid through the container 4.

[0026] The arrangement of figure 7 is particularly advantageous, as it allows to maximize the volumetric energy density of the battery pack, minimizing the empty spaces within the container 4. In both the case of figure 7 and figure 8, the container has a single inlet for the thermoregulating liquid (not shown in these figures).

[0027] The solution in figure 6, with modules 1 independent of each other, has a lower volumetric energy density than the case in figures 7, 8.

[0028] Figures 9, 10 show the different layouts of the thermoregulating liquid circuit in two battery packs with independent modules 1 (figure 9) and with cell stacks 101 contained in a common container to which a single circuit for the thermoregulating liquid is associated (figure 10). In the case of figure 10, battery separators are arranged between the different cell stacks.

[0029] Technical problem

[0030] In a battery pack of the known type illustrated in figures 7 and 8, with multiple stacks of battery cells arranged within a common container that is passed through by the flow of thermoregulating liquid, there is the problem of obtaining correct thermoregulation of all the cells of all the stacks of battery cells by promoting a substantially uniform flow rate of the thermoregulating liquid in the different stacks of battery cells and between the different cells of each stack.

[0031] The Applicant has already proposed various solutions (see Italian patent applications IT102023000022704, IT102023000022698, IT102023000022692, still secret at the priority date of the present invention), aimed at achieving a uniform distribution of the flow of the thermoregulating liquid between the different spaces between the cells of a single battery module, and in order to make the flow of the thermoregulating liquid uniform in each space between two cells, for the entire width of the cells.

[0032] However, in a battery pack having the arrangement of figure 8, there is the additional problem, for the reasons that will be explained in detail here below, of making the flow of the thermoregulating liquid uniform between the different stacks of battery cells.

[0033] A second technical problem is that of the “swelling”, or increase in volume, of the battery cells, both due to aging and heating: there are always countermeasures that tend to limit this phenomenon. These countermeasures must not be in conflict with the solutions aimed at ensuring the uniform distribution of the flow of the thermoregulating liquid.

[0034] A battery pack having the features indicated in the preamble of claim 1 is known from document FR 3 140 214 A1. This document illustrates a battery pack with prismatic cells in which a spacer frame in the form of a frame is placed between each cell, the lower portion of which has slits defining restricted passages designed to create sufficient resistance to the passage of the thermoregulating liquid to discourage a tendency for the thermoregulating liquid to flow more in some spaces between the cells rather than in others. Said document also illustrates a battery pack with cylindrical cells, in which the restricted passages are defined by holes in shells arranged below and above the cylindrical cells. Finally, said document also illustrates a battery pack with pouch-type cells, in which the restricted passages are defined by holes in a plate arranged below the cells, and in which spacer frames in the form of corrugated sheet metal panels are placed between each cell, defining a plurality of separate paths for the thermoregulating liquid, which do not favor a uniform and homogeneous distribution of the thermoregulating liquid across the entire width of each cell.

[0035] Object of the invention

[0036] The object of the present invention is to solve said technical problems.

[0037] In particular, the invention has as its object the provision of an electric battery pack of the type indicated at the beginning of the present description, in which the temperature of the cells is maintained within a specified range in any operating condition, thanks to the high efficiency of the heat exchange with the thermoregulating liquid.

[0038] In even more detail, the main object of the invention is to optimize the heat exchange between the cells and the thermoregulating liquid thanks to a uniform distribution of the thermoregulating liquid between the different modules of the battery pack and between the different spaces between the cells of each module

[0039] Summary of the invention

[0040] In view of achieving one or more of said aims, the invention has as its object an electric battery pack having the features indicated in the attached claim 1 .

[0041] Further advantageous features of the invention are indicated in the dependent claims.

[0042] Detailed description of the invention

[0043] Further features and advantages of the invention will be apparent from the following description with reference to the attached drawings, provided purely by way of non-limiting example, in which:

[0044] Figure 1 is a perspective view of a battery module according to the prior art,

[0045] Figure 2 is a perspective view of a prismatic type battery cell,

[0046] Figure 3 is a schematic sectional view of the battery module of Figure 1 ,

[0047] Figure 4 is a schematic perspective view of an array of battery cells in a battery module according to the prior art,

[0048] Figure 5 is a perspective view of a further example of a spacer frame, used to space the battery cells of the same battery module from each other,

[0049] Figure 6 is a perspective view of a battery pack of the prior art type with a plurality of modules having independent containers each provided with a respective circuit for the thermoregulating liquid,

[0050] Figure 7 is a perspective view of a battery pack of a type to which the present invention is applicable, with a plurality of battery cell stacks arranged within a common container,

[0051] Figure 8 is a schematic plan view of a battery pack of the type of figure 7,

[0052] Figures 9, 10 show the different layouts of the circuit of the thermoregulating liquid in the case of a battery pack with independent modules and a battery pack with a plurality of battery cell stacks immersed in a single circuit for the thermoregulating liquid,

[0053] Figure 11 illustrates the flows of the thermoregulating liquid through the battery pack of the invention as solid parts,

[0054] Figure 12 is a plan view showing the flow of the thermoregulating liquid associated with a battery cell stack forming part of a battery pack according to the invention,

[0055] Figure 13 is a perspective view illustrating a single battery cell of a battery cell stack, and the ribs made of non-conductive material used to support the battery cells of the same stack,

[0056] Figure 14 is an enlarged perspective view of a detail of the figure 13, which shows an example of an embodiment of the invention,

[0057] Figure 15 is a schematic and plan view of the support structure at the base of a stack in the battery pack according to the invention,

[0058] Figure 16 is a schematic plan view of part of the circuit of the thermoregulating liquid, in a battery pack according to a preferred embodiment of the invention,

[0059] Figure 17 is a schematic perspective view of a battery cell forming part of a preferred embodiment of the invention, and

[0060] Figure 18 is a perspective view of a battery pack with cylindrical cells, which does not form part of the present invention.

[0061] Figures 1 -10, already described above, show known arrangements of battery modules and battery packs with modules having independent circuits for the thermoregulating liquid and battery packs of the type to which the present invention refers, i.e. with stacks of cells contained in a common container and immersed in a common circuit for the thermoregulating liquid.

[0062] The battery pack of the invention may be of the same type illustrated in figure 7 and schematized in figure 8, with a container 4 within which two rows of stacks 101 are arranged, along directions parallel to the direction Y, with the cells 2 of each stack 101 arranged side by side in the direction X. Figure 8 is purely schematic, so it does not show the spaces between the cells 2, nor does it show the construction details of the battery pack 100. Furthermore, in figure 8, as already indicated, the spaces between the stacks 101 and the spaces between the stacks 101 and the container 4 have been exaggerated for clarity. In fact, such spaces are kept as small as possible, to increase the volumetric energy density of the battery pack.

[0063] Of course, the invention is also applicable to different configurations, with a different number of rows of stacks 101 , with a different number of stacks along each row and with a different number of cells in each stack.

[0064] Figure 11 of the accompanying drawings illustrates, as solid parts, the flows of the thermoregulating liquid through the battery pack according to the invention (only one half of the battery pack is illustrated, with the row of stacks 101 that are on one side of the median longitudinal axis 11 of the pack of figure 8).

[0065] The container of the battery pack is configured so that in each stack 101 the thermoregulating liquid flows from an inlet collector chamber 13A that extends below the cells 2 of the stack, through the spaces between the cells and up to an outlet collector chamber 13B that extends above the cells of the stack. In figure 11 , for simplicity of illustration, for each stack the flows of the thermoregulating liquid through only three of the spaces between the cells of the stack have been illustrated as solid parts: the two spaces at the ends of the stack and the space halfway along the length of the stack.

[0066] The container 4 is also configured to define a distribution conduit 10 for the thermoregulating liquid entering the container 4, extending below the stacks 101 along the direction Y, from an inlet 12, at a first end 4A of the container 4 to a second end 4B of the container 4, and configured to distribute the thermoregulating liquid to the inlet collector chambers 13A of the different battery cell stack 101.

[0067] The container 4 is also configured to define an outlet collector conduit 14 of the thermoregulating liquid, that extends above the stacks 101 , along the direction Y, from said second end 4B of the container 4 toward said first end 4A of the container 4, up to an outlet 15. The outlet collector conduit 14 is configured to collect the flow of the thermoregulating liquid from the outlet collector chambers 13B of the different stacks 101 , and to carry it to the outlet 15.

[0068] As a result of the arrangement described above, the thermoregulating liquid from the distribution conduit 10, pushed by the feed pump 10, tends to have a stagnation zone, with higher pressure and lower speed, in the inlet collector chamber 13A of the stack 101 closest to the end 4B of the container 4, i.e. the stack 101 which is furthest from the inlet 12.

[0069] For this reason, the thermoregulating liquid may tend to accumulate at the end 4B of the container 4, thus preventing efficient thermoregulation of said cell stack and making the distribution of the thermoregulating liquid uneven between the different cell stacks and also making the distribution of the flow uneven in the inlet collector chamber 13A of the stack 101 adjacent to the end 4B of the container 4.

[0070] To solve said problem, the preferred embodiment of the invention provides the arrangement described below.

[0071] In the battery pack, the cells 2 of each battery cell stack 101 (see figure 13) are supported on a plurality of straight ribs 300 of electrically insulating material, parallel and spaced apart from each other, extending in the longitudinal direction X of each battery cell stack 101 . The ribs 300 are immersed in the inlet collector chamber 13A of each battery stack, located below the battery cells 2.

[0072] Preferably, in order to reduce as much as possible a tendency of the thermoregulating liquid to increase in pressure adjacent to the end 4B of the container 4, each rib 300 is provided with a series of upper notches 400, spaced apart from each other, distributed along the entire length of each rib 300, and each positioned where a respective cell 2 rests on the rib 300 (see figure 14).

[0073] In this way, a uniform distribution of the thermoregulating liquid from the distribution conduit 10 is promoted across the entire width (along the direction Y) of the inlet collector chamber 13A of the stack 101 adjacent to the end 4B of the container 4.

[0074] According to a further preferred feature, with reference to figure 15, the supporting ribs 300 that are closer to said second end 4B of the container 4 have notches 400 of greater length. Preferably, in the stack 101 that is closer to the second end 4B of the container 4, the supporting ribs 300 have notches 400 of length L that progressively increases as the distance of the rib 300 from the second end 4B of the container 4 decreases. Furthermore, always preferably, as illustrated in figure 15, the notches 400 are in such positions as to encourage a circulatory motion in a horizontal plane of the thermoregulating liquid.

[0075] With reference to figure 16, in a preferred embodiment of the invention, in order to counteract a tendency of the thermoregulating liquid to increase excessively in pressure at the inlet collector chamber 13A of the stack 101 closest to the end 4B of the container 4, the end of the conduit 10 for distributing the thermoregulating liquid communicates with the inlet collector chamber 13A of said stack 101 through a labyrinth passage defined by a septum 10A that prevents direct communication between the end of the conduit 10 and the inlet collector chamber 13A of said stack 101 . The septum 10A is conformed in such a way that the flow of the thermoregulating liquid reaches up to dead end of the conduit 10, where it increases in pressure, but then returns up to a passage 10B from which it starts to flow again to the inlet collector chamber 13A below the cells 2 of said stack. 101 .

[0076] The labyrinth passage can also be provided at the other stacks, in the part of the conduit 10 adjacent to the side of each stack furthest from the inlet 12 (figure 11 ). The labyrinth passage has the function of uncoupling the main flow that flows in the conduit 10 from the fluid that, bending 90°, enters the different stacks. The septum that defines the labyrinth passage can be of different lengths depending on the distance of each stack from the inlet 12: at the last stack (i.e. in the stack furthest from the inlet 12) it can have an axial length equal to at least 1 / 3 of the size of the stack in the direction Y (always with reference to figure 11 ). In the stack immediately upstream, the extension of the septum defining the labyrinth passage may be at least a quarter of the size of the stack in the direction Y. In the stack still upstream, the size in the direction Y of the labyrinth passage may be at least a fifth.

[0077] In a variant that is not the subject of the present invention, the expedient consisting of providing one or more labyrinth passages of the type described above may also be provided in a battery pack in which, instead of stacks of prismatic cells, stacks of cylindrical cells are used. In this case, the battery cell stacks are defined by a single continuous assembly of cylindrical cells 2 arranged with their axes vertical and in contact with each other, so that the spaces between the cylindrical cells connect the inlet collector chamber located below the cells with the outlet collector chamber located above the cells (figure 18), one or more labyrinth passages being associated with groups of cylindrical cells that are further away from the inlet for the thermoregulating liquid in the container.

[0078] With reference to figure 17, according to the main feature of the invention, the cells 2 of each stack 101 are separated from each other, instead of by frames of the type illustrated in figure 5, by panels 30 of porous material. For example, each panel 30 comprises one or more layers of a mesh 30A made of wires of a material chosen based on the need to electrically isolate the cells: in the case of a low risk of short circuit between the cells (perhaps because they are already sufficiently protected), a stainless steel is the best choice, with mesh wire diameters of approximately 0.2 mm. On the contrary, in the case of cells with reduced protection, adequate electrical insulation is required and therefore preferably a steel coated with insulating paint or other protective coating can be used, or even a superpolymer such as polyether ether ketone (PEEK), resistant to high temperatures: in this case the mesh could be made by 3D printing or by winding in multiple layers. Another advantage of superpolymers is that they would thermally insulate the cells from each other in the event of uncontrolled thermal runaway, since the softening temperature of superpolymers exceeds 200 °C.

[0079] Studies and experiments of the Applicant have shown that the use of panels made of porous material of the type of panel 30 of figure 17 as spacer elements between the cells allows for a much more homogeneous and uniform flow of the thermoregulating liquid in the spaces between the cells.

[0080] In order not to compromise the anti-swelling function (which tends to prevent a swelling of the cells during use) performed by rigid spacer frames of the type of that of figure 5, the panel 30 made of porous material can include a plurality of rigid inserts 40 made of plastic material, for example.

[0081] The panels 30 are used in combination with the provision of spacer elements 8, for example of the type illustrated in figure 4, defining one or more restricted passages for the communication of the inlet collector chamber 13A located under the cells 2 with the spaces between the cells. As already indicated in the solutions previously proposed by the same Applicant, said restricted passages have the purpose of creating a resistance to the passage of the thermoregulating liquid sufficient to discourage a tendency of the thermoregulating liquid to flow more into the spaces between the cells that are closer to the inlet and / or outlet of the thermoregulating liquid in and from the container 4.

[0082] With reference to figure 17, the space between each cell and the other is occupied in a lower part thereof by the lower spacer element 8, in which said restricted passages are formed (for example in the form of slits), and in an upper part thereof by a respective panel 30 made of porous material, comprising one or more layers of mesh.

[0083] The provision of one or more mesh layers has the inevitable consequence of defining a random tangle of passages, which facilitates the uniform and homogeneous distribution of the flow of the thermoregulating liquid across the entire width of the cell.

[0084] Of course, notwithstanding the principle of the invention, the construction details and the embodiments may vary widely with respect to what is described and illustrated purely by way of example, without thereby departing from the scope of the present invention, as defined in the attached claims.

Claims

CLAIMS1. Electric battery pack, comprising:- a container (4) of the battery pack,- a plurality of stacks (101 ) of battery cells (2) arranged within the container (4) of the battery pack and each including an array of battery cells (2),- wherein the cells (2) of each battery cell stack (101 ) are arranged parallel to each other, and spaced apart from each other along a first horizontal direction (X),- wherein the battery cell stacks (101 ) are arranged in one or more rows parallel to each other along a second horizontal direction (Y) orthogonal to the first horizontal direction (X),- wherein the battery cells (2) of each pair of battery cells (2) adjacent to each other have main surfaces (2P) facing to each other, between which spacer elements (8, 80, 30) are interposed, so as to define a space between the cells,- wherein all the battery cells (2) of all the battery cell stacks (101 ) are in direct contact with a flow of a thermoregulating liquid which flows through the container (4) of the battery pack, for the purpose of maintaining the battery pack within a specified temperature range,- wherein the container (4) of the battery pack is configured so that in each stack (101 ) the thermoregulating liquid flows from an inlet collector chamber (13A) that extends below the cell stack, through the spaces between the cells (2) and up to an outlet collector chamber (13B) that extends above the cells (2) of the stack (101 ), wherein the container (4) is also configured to define:- an inlet distribution conduit (10) for distributing the thermoregulating liquid entering the container (4), extending below the battery cell stacks (101 ) along said second direction (Y), from a first end (4A) of the container (4) to a second end (4B) of the container (4), and configured to distribute the thermoregulating liquid to the inlet collector chambers (13A) of the various battery cell stacks (101 ), and- an outlet collector conduit (14) of the thermoregulating liquid, extending above the battery cell stacks (101 ), along said second direction(Y), from said second end (4B) of the container (4) toward said first end (4A) of the container (4), and configured to collect the flow of the thermoregulating liquid from the outlet collector chambers (13B) of the different stacks (101 ), wherein the spacer elements (8, 80, 30) interposed between the cells define one or more restricted passages for the communication of the inlet collector chamber (13A) located under the cells (2) with the spaces between the cells (2), said restricted passages being configured to create a resistance to the passage of the thermoregulating liquid sufficient to discourage a tendency of the thermoregulating liquid to flow more into the spaces between the cells which are closest to an inlet and / or an outlet for the thermoregulating liquid which are provided in the container (4) said battery pack being characterized in that the space between each cell (2) and the other is occupied in a lower part thereof by a lower spacer element (8) in which said restricted passages are formed, and in an upper part thereof by a respective panel of porous material (30) comprising one or more layers of a mesh (30A) made of stainless steel, or steel coated with an insulating layer, or one or more layers of a mesh made of polymeric material, preferably a superpolymer, even more preferably PEEK.

2. Battery pack according to claim 1 , characterized in that the panels (30) of porous material comprise a plurality of rigid inserts (40) having the function of tending to prevent a swelling of the battery cells (2) during their use.

3. Battery pack according to claim 1 , characterized in that:- the cells (2) of each battery cell stack (101 ) are supported on a plurality of parallel and spaced apart ribs (300), extending in said first direction (X),- each of said supporting ribs (300) having a plurality of upper notches (400), distributed along the respective rib (300) and each located in a portion of the rib (300) above which a battery cell (2) is supported, so as to establish communication between different portions of the input collector chamber (13A) below the cells (2) of each stack (101 ).

4. Battery pack according to claim 3, characterized in that the supporting ribs (300) that are closer to said second end (4B) of the container (4) have notches (300) of greater length.

5. Battery pack according to claim 3, characterized in that in the battery cell stack (101 ) which is closest to the second end (4B) of the container (4) the supporting ribs (300) have notches (400) of progressively greater length as the distance of the rib (300) from the second end (4B) of the container (4) decreases, the notches (400) being preferably arranged in such positions as to encourage a circulatory motion in the horizontal plane of the thermoregulating liquid.

6. Battery pack according to claim 1 , characterized in that the end of the inlet distribution conduit (10) for the thermoregulating liquid (10) communicates with the inlet collector chamber (13A) of the stack (101 ) that is closer to said second end (4B) of the container (4) via a labyrinth passage defined by a septum (10A) that prevents direct communication between the end of the inlet distribution conduit (10) of the thermoregulating liquid and the inlet collector chamber (13A) of said stack (101 ), said septum (10A) being conformed in such a way that the flow of the thermoregulating liquid reaches up to dead end of the inlet distribution conduit of the thermoregulating liquid (10), where it increases in pressure, but then returns up to a passage (10B) from which it flows again to the inlet collector chamber (13A) below the cells (2) of said stack (101 ).

Images