BATTERY PACK INCLUDING BATTERY CELLS AND SOLENOID VALVES ON A LOWER COVER, VEHICLE AND PROCESS BASED ON SUCH A BATTERY PACK

Abstract

The invention relates to a battery pack comprising battery cells (C), receiving a cooling fluid (F), and comprising a lower cover (CI) including circulation channels for said fluid (F) carrying non-return solenoid valves. The battery pack includes at least one controller (M) connected to the solenoid valves (E), and to at least one means for evaluating the fluid level (F) in the battery pack. The controller (M) controls the opening or closing of each solenoid valve (E) if the fluid level (F) is respectively at a first or second threshold level above or below the level of said solenoid valve (E). The invention also relates to a vehicle and a method for manufacturing such a battery pack. Figure 2

Description

Title of the invention: BATTERY PACK COMPRISING BATTERY CELLS AND SOLENOID VALVES ON A BOTTOM COVER, VEHICLE AND METHOD BASED ON SUCH A BATTERY PACK

[0001] The invention relates to the field of cooling systems for motor vehicle battery cells, in particular cooling systems by spraying a dielectric fluid.

[0002] Certain prior art solutions illustrated in [Fig.l], propose using sprays of dielectric fluid F to cool and control the temperature of the cells of a battery pack. The fluid F is sprayed onto the top of the cells C and then flows along the large faces of the cells C mainly, in order to reach a partial immersion at the bottom of the pack.

[0003] The fluid supply and return functions are integrated into a lower cover CI via channels CA, as shown in [Fig.l]. The fluid leaving the pack will enter a cold loop external to the pack in which this fluid will be cooled via an exchanger. The fluid will be extracted from the pack via ports in the lower cover CL

[0004] The fluid F is distributed in this cold loop via a pump which risks losing its prime if the circuit is not completely filled with fluid F. However, the battery pack, integrally linked to the vehicle, will undergo inclinations and accelerations which could lose its prime this pump.

[0005] An objective of the present invention is to remedy the defects of the prior art, and in particular to propose a solution limiting the risk of the pump losing its prime when the circuit is not completely filled with fluid.

[0006] To achieve this objective, the invention proposes a battery pack comprising battery cells in a spatial reference frame comprising a longitudinal axis along a longitudinal direction of the battery pack; a lateral axis perpendicular to the longitudinal axis, and a vertical axis perpendicular to the longitudinal axis and to the lateral axis, the battery pack being configured to receive a cooling fluid, and comprising a lower cover arranged below the battery cells along the vertical axis, the lower cover comprising channels for circulation of said fluid, characterized in that the lower cover further comprises non-return solenoid valves on the channels; in that the battery pack comprises at least one controller connected to the solenoid valves, and configured to be connected to at least one means for evaluating the fluid level in the battery pack, and in that the controller controls the opening of each solenoid valve if the fluid level is at a first threshold level above said solenoid valve along the vertical axis; and the closing of said solenoid valve if the fluid level is at a second threshold level below said solenoid valve along the vertical axis.

[0007] Advantageously, the invention makes it possible to limit the risk of the pump losing its prime when the circuit is not completely filled with fluid.

[0008] According to a variant, the lower cover comprises four channels and four non-return solenoid valves on the channels.

[0009] This allows the solenoid valves to be arranged at four points spaced apart.

[0010] According to a variant, the means for evaluating the fluid level comprise at least one fluid level sensor of the battery pack and / or are coupled to at least one inclination sensor of the battery pack. In particular, it is a inclination sensor of a motor vehicle comprising said battery pack.

[0011] This makes it easy to assess which way the fluid in liquid form will move.

[0012] According to one variant, the battery pack comprises two fluid level sensors and a tilt sensor.

[0013] This provides complete information on the fluid level near the channel.

[0014] According to one variant, the battery pack comprises four fluid level sensors.

[0015] This makes it possible to precisely assess the fluid level near the channel.

[0016] The invention further relates to a motor vehicle comprising a battery pack according to the invention.

[0017] Another subject of the invention relates to a method of manufacturing a motor vehicle comprising a battery pack according to the invention, the manufacturing method comprising the following steps: - a step of installing the lower cover including the channels and the non-return solenoid valves; - a step of setting up the controller and connecting the controller to the solenoid valves; - a step of connecting the controller to said fluid level evaluation means.

[0018] The invention further relates to a method for controlling a battery pack according to the invention, comprising the following steps: - an evaluation step in which the fluid level in the battery pack is evaluated; - a control step in which the opening of each solenoid valve is controlled if the fluid level is at a first threshold level above said solenoid valve; and the closing of said solenoid valve if the fluid level is at a second threshold level below said solenoid valve.

[0019] The invention further relates to a computer program comprising program code instructions for executing the steps of the control method according to the invention, when said program operates on a computer.

[0020] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates a front view of a battery pack arrangement according to the prior art; - [Fig.2] schematically illustrates a front view of a battery pack arrangement according to the invention; - [Fig.3] schematically illustrates a view in space from above of a lower cover of a battery pack according to the invention; - [Fig.4] schematically illustrates a top view of a lower cover of a battery pack of the invention in a first configuration; and - [Fig.5] schematically illustrates the top view of the lower cover of [Fig.4] in a second configuration.

[0021] The invention relates to a battery pack suitable for a spray cooling solution, illustrated in Figures 2 to 5.

[0022] This solution proposes to use sprays of dielectric fluid F to cool and control the temperature of the cells of a battery pack. The fluid F is sprayed onto the top of the cells C and then flows along the large faces of the cells C mainly, in order to reach a partial immersion at the bottom of the pack.

[0023] The inventors have proposed a battery pack with a novel arrangement. The battery pack comprises battery cells C arranged next to each other in a spatial reference frame comprising a longitudinal axis X along a longitudinal direction of the battery pack; a lateral axis Y perpendicular to the longitudinal axis X, and a vertical axis Z perpendicular to the longitudinal axis X and to the lateral axis Y.

[0024] The fluid supply and return functions are integrated into a lower cover CI of the battery pack (via channels CA illustrated in [Fig.2]). The fluid F leaving the battery pack enters a cold loop external to the battery pack in which this fluid F will be cooled via a heat exchanger (not shown). The fluid F is extracted from the battery pack via orifices (channels CA) in the lower cover CL

[0025] The fluid F is distributed in this cold loop via a pump (not illustrated) which risks losing its prime if the circuit is not completely filled with fluid F. However, the battery pack, integrally linked to the vehicle, is subject to inclinations and accelerations which could lose its prime this pump.

[0026] To address this problem of possible loss of priming of the fluid circuit, we propose replacing these orifices CA with four controlled solenoid valves E distributed in the bottom of the battery pack which are only open when fluid F is present at a first threshold level above their surface, for example above 15 to 25% of the height of a cell C, preferably above 20% of the height of a cell C.

[0027] [Fig.3] shows an arrangement of these solenoid valves E at the bottom of the battery pack. When flat, the four solenoid valves have a sufficient quantity of fluid F on their surface. Depending on the movement of the battery pack, one or more solenoid valves E may no longer have sufficient fluid F on the surface and this must then be detected and closed to avoid any risk of the pump losing its prime.

[0028] The solenoid valves E can be closed when the fluid F drops to a second threshold level lower than the threshold level, for example below 5 to 15% of the height of a cell C, preferably below 10% of the height of a cell C.

[0029] The strategies of the invention for controlling these solenoid valves E are based on two possibilities: the use of a vehicle inclination sensor I or the use of fluid level sensors N.

[0030] The first possibility consists of using the vehicle inclination information to determine the solenoid valves E to open or close. Indeed, when the vehicle tilts in one direction, the battery pack follows the same inclination and it is possible to determine the solenoid valves E where there will be a drop in fluid F. Indeed, it is possible first of all to carry out simulations in order to determine these solenoid valves E, then validate these simulations by tests. In an illustrative example: either an inclination measured by the vehicle only around the X axis, depending on the sign of rotation (+x) or (-x) the strategy will consist either of opening the two valves on one side ([Fig.4]) or on the other ([Fig.5]).

[0031] Thus, in the case of [Fig.4] for example, all the fluid F will be present on the surface of the two solenoid valves on the high side which will be controlled in the open position, while the other two solenoid valves E will be closed to avoid depriming the pump. Depending on the vehicle inclination, one or more solenoid valves E will be open in order to circulate the fluid F, the others remaining closed.

[0032] The second possibility consists of using the fluid level sensors N which will be present in the battery pack, alone or coupled with the vehicle inclination information, to determine the solenoid valve(s) E to open. Here we can propose coupling each solenoid valve E to a fluid level sensor N in order to best estimate the level in all circumstances. This allows for simplified independent control of each solenoid valve E based on the measurement from the level sensor N. Indeed, in this configuration, it is sufficient to read the sensor information from level N for each solenoid valve E in order to control it in the open or closed position.

[0033] On the other hand, this solution leads to considering four level sensors N which can be optimized. We can imagine limiting ourselves to two level sensors instead of four, but in this case, it will possibly be necessary to couple with the vehicle inclination information to determine the solenoid valves E to leave open. Similarly, if we manage to use only one level sensor N, we will have to use mainly the vehicle inclination information to control the solenoid valves E.

[0034] In a variant, the invention comprises a system of four solenoid valves E controlled using one or more pieces of information (vehicle tilt sensor I and / or fluid level sensor(s) N in the battery pack) in order to ensure that fluid F will be present in the fluid return circuit, thus avoiding the risk of the pump losing its prime.

Claims

Claims

1. Battery pack comprising battery cells (C) in a spatial reference frame comprising a longitudinal axis (X) along a longitudinal direction of the battery pack; a lateral axis (Y) perpendicular to the longitudinal axis (X), and a vertical axis (Z) perpendicular to the longitudinal axis (X) and to the lateral axis (Y), the battery pack being configured to receive a cooling fluid (F), and comprising a lower cover (CI) arranged below the battery cells (C) along the vertical axis (Z), the lower cover (CI) comprising channels (CA) for circulation of said fluid (F), characterized in that the lower cover (CI) further comprises non-return solenoid valves on the channels (CA);in that the battery pack comprises at least one controller (M) connected to the solenoid valves (E), and configured to be connected to at least one means (N, I) for evaluating the fluid level (F) in the battery pack, and in that the controller (M) controls the opening of each solenoid valve (E) if the fluid level (F) is at a first threshold level above said solenoid valve (E) along the vertical axis (Z); and the closing of said solenoid valve (E) if the fluid level (F) is at a second threshold level below said solenoid valve (E) along the vertical axis (Z).;

2. Battery pack according to claim 1, characterized in that the lower cover (CI) comprises four channels (CA) and four non-return solenoid valves (E) on the channels (CA).

3. Battery pack according to any one of claims 1 to 2, characterized in that the means for evaluating the fluid level (N, I) comprise at least one fluid level sensor (N) of the battery pack and / or are coupled to at least one inclination sensor (I) of the battery pack.

4. Battery pack according to claim 3, characterized in that it comprises two fluid level sensors (N) and a tilt sensor (I).

5. Battery pack according to claim 3, characterized in that it comprises four fluid level sensors (N).

6. A motor vehicle comprising a battery pack according to any one of claims 1 to 5.

7. Method of manufacturing a motor vehicle comprising a pack battery according to any one of claims 1 to 5, the manufacturing method comprising the following steps: - a step of installing the lower cover (CI) including the channels (CA) and the non-return solenoid valves (E); - a step of setting up the controller (M) and a connection of the controller (M) to the solenoid valves (E); - a step of connecting the controller (M) to said fluid level evaluation means (N, I).

8. A method of controlling a battery pack according to any one of claims 1 to 5, comprising the following steps: - an evaluation step in which the fluid level (N, I) in the battery pack is evaluated; - a control step in which the opening of each solenoid valve (E) is controlled if the fluid level (F) is at a first threshold level above said solenoid valve (E); and the closing of said solenoid valve (E) if the fluid level (F) is at a second threshold level below said solenoid valve (E).

9. A computer program comprising program code instructions for executing the steps of the control method according to claim 8, when said program is running on a computer.

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