BATTERY BLOCK WITH COOLING MEANS

Abstract

One aspect of the invention relates to a battery block (1) comprising a plurality of rows (2) of cells, stringers (4) arranged between said rows (2) of cells, a receptacle (5) receiving said plurality of rows (2) of cells and said stringers (4), and means for cooling said cells.The cooling means (6) comprise: a circulation circuit (7) of a dielectric fluid disposed in a bottom (8) of said receptacle (5) and in a thickness of said stringers (4), means for spraying said dielectric fluid onto said rows (2) of cells, said spraying means (9) passing through an upper surface (10) of said stringers (4) and communicating with said circulation circuit (7), means for extracting said sprayed dielectric fluid passing through said upper surface (10) and opening into said circulation circuit (7), and a cooling circuit (12) of said dielectric fluid connected to said circulation circuit (7). Figure 1.

Description

Title of the invention: BATTERY PACK COMPRISING COOLING MEANS

[0001] The invention relates generally to the cooling of vehicle accumulator batteries. More particularly, the invention relates to a vehicle battery pack provided with cooling means.

[0002] A battery pack, also called a battery, is an assembly of electrochemical cells, also called electrical storage cells or cells, each of which is an elementary unit for converting chemical energy into electrical energy, and vice versa. The cells are connected in series and / or in parallel and must be in sufficient number to achieve the desired characteristics for the battery pack, in particular, in terms of voltage, current and energy storage capacity. The temperature of the cells must be maintained within an optimal temperature range, without ever exceeding high limits defined by the manufacturers, in order to guarantee its performance and durability.

[0003] In an electric or hybrid vehicle, the battery pack used for traction of the vehicle, for example a lithium-ion battery pack, heats up significantly during the charging and discharging phases thereof. Furthermore, the need to reduce the recharging time of the battery pack, particularly in high energy capacity electric vehicles, has led to the development of very high power recharging, known as "HPC or UFC" for "High Power Charging or Ultra Fast Charging" in English. HPC recharging imposes increased thermal constraints on the battery pack. Typically, during HPC recharging, the temperature of a lithium-ion battery must not exceed 50°C in order to guarantee operational safety and avoid premature aging thereof.

[0004] Air cooling systems can be used to ensure thermal conditioning of the battery pack. For example, document US-B2-10665915 discloses a cooling circuit for the battery pack formed through the structure of the battery pack, associated with outlets positioned facing the battery modules so as to inject air onto the faces of the battery modules.

[0005] Such an air cooling system does not allow the cells of a battery pack to be cooled effectively, particularly during a very high HPC power recharging phase.

[0006] The aim of the invention is to overcome the drawbacks of the prior art by proposing a battery pack comprising cooling means making it possible to effectively cool the cells of the battery pack, in particular during very high-speed recharging phases. high power.

[0007] In this context, the invention thus relates, in its broadest sense, to a battery pack comprising a plurality of rows of cells, side members arranged between the rows of cells, a receptacle receiving the plurality of rows of cells and the side members, and means for cooling the cells. The means for cooling the cells comprise: • a circuit for circulating a dielectric fluid placed in the bottom of the receptacle and in a thickness of the side members, • means for spraying the dielectric fluid onto the rows of cells, the spraying means passing through an upper surface of the side members and communicating with the circulation circuit, • means for extracting the sprayed dielectric fluid passing through the upper surface and opening into the circulation circuit, and • a dielectric fluid cooling circuit connected to the dielectric fluid circulation circuit.

[0008] Thanks to the invention, a dielectric fluid cooled by the cooling circuit is sprayed directly onto rows of cells. Thus, the cells of the battery pack are cooled efficiently and uniformly, including during a very high HPC power recharging phase.

[0009] Furthermore, the circulation circuit, the spraying means and the means for extracting the dielectric fluid are arranged in the structure of the battery pack, namely the bottom of the receptacle and the side members. This particular arrangement makes it possible to reduce the size of the battery pack.

[0010] In addition to the characteristics which have just been mentioned in the preceding paragraph, the battery pack according to one aspect of the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations.

[0011] According to one aspect of the invention, on a spar, the spraying means are aligned in a row.

[0012] According to one aspect of the invention, on a spar, the spraying means are arranged alternately in two rows.

[0013] According to one aspect of the invention, on a spar, each spraying means is arranged to spray the dielectric fluid onto one of the two rows of cells juxtaposed to the spar.

[0014] According to one aspect of the invention, on a spar, each spraying means is arranged to spray the dielectric fluid onto the two rows of cells juxtaposed to the spar.

[0015] According to one aspect of the invention, the spraying means are formed by: • holes made in the side members, • calibrated valves placed in the side members, or • adjustable nozzles.

[0016] According to one aspect of the invention, the extraction means are formed by one-way valves.

[0017] According to one aspect of the invention, the cooling circuit comprises a device for cooling the dielectric fluid and means for pressurizing the dielectric fluid, said pressurizing means comprising: • low pressure pressurization means arranged to pressurize the dielectric fluid at low pressure, and • high pressure pressurization means arranged to pressurize the dielectric fluid at high pressure.

[0018] According to one aspect of the invention, the high pressure pressurization means are arranged in the circulation circuit of the dielectric fluid.

[0019] Another aspect of the invention relates to a method for cooling a battery pack according to any one of the aforementioned aspects of the invention, the battery pack being arranged in a vehicle provided with means for measuring the temperature of the battery pack and a cooling management computer, the method comprising, when the temperature of the battery pack exceeds a threshold value, a step of triggering, via the cooling management computer, a high-pressure circulation of the dielectric fluid in the dielectric fluid circulation circuit so as to spray the dielectric fluid onto the rows of cells.

[0020] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0021] [fig. 1] schematically illustrates a battery pack according to a non-limiting aspect of the invention.

[0022] [fig.2] schematically represents a top view of the battery pack illustrated in [fig.l],

[0023] [fig.3] schematically illustrates a battery pack according to another aspect not limiting of the invention.

[0024] [fig.4] illustrates three examples of embodiments of spraying means which comprise a battery pack according to a non-limiting aspect of the invention.

[0025] [fig.5] schematically illustrates a method of cooling a battery pack according to a non-limiting aspect of the invention.

[0026] [Fig. 1] schematically illustrates a battery pack 1 according to a non-limiting aspect of the invention. [Fig. 2] illustrates a top view of the battery pack 1 illustrated in [Fig. 1].

[0027] For the remainder of the description, reference will be made to Figures 1 and 2.

[0028] The battery pack 1 is intended for use in an electric or hybrid vehicle.

[0029] The battery pack 1 comprises a plurality of rows 2 of cells 3. These cells 3 are electrical storage cells.

[0030] The battery block 1 also comprises longitudinal members 4 arranged between the rows 2 of cells 3. These longitudinal members 4 ensure in particular the maintenance of the rows 2 of cells 3.

[0031] The battery block 1 further comprises a receptacle 5 receiving in particular the rows 2 of cells 3 and the side members 4.

[0032] The battery pack 1 further comprises means 6 for cooling the cells 3.

[0033] These cooling means 6 comprise a circulation circuit 7 for a dielectric fluid. This circulation circuit 7 for a dielectric fluid is arranged in the bottom 8 of the receptacle 5 and in a thickness of the side members 4. In other words, in order to be able to accommodate dielectric fluid, the side members 4 are hollow.

[0034] It should be noted that the lower end of the cells 3 is positioned in the circulation circuit 7 of the dielectric fluid.

[0035] These cooling means 6 further comprise means 9 for spraying the dielectric fluid onto the rows 2 of cells 3. The spraying means 9 pass through an upper surface 10 of the side members 4 and communicate with the circulation circuit 7 of the dielectric fluid.

[0036] In this embodiment, the spraying means 9 are formed by orifices provided in the upper surface 10 of the side members 4.

[0037] In another exemplary embodiment not illustrated, the spraying means 9 are formed by calibrated valves arranged to spray the dielectric fluid when the pressure in the circulation circuit 7 exceeds a predetermined value.

[0038] In another exemplary embodiment not illustrated, the spraying means 9 are formed by orientable nozzles. The nozzles of a spar 4 can for example be arranged on an electrically orientable ramp.

[0039] These cooling means 6 further comprise means 11 for extracting the sprayed dielectric fluid. These extraction means 11 pass through the upper surface 10 of the side members 4 and open into the circulation circuit 7 of the dielectric fluid.

[0040] The extraction means 11 can for example be formed by one-way valves.

[0041] The cooling means 6 further comprise a cooling circuit 12 for the dielectric fluid.

[0042] The cooling circuit 12 is connected to the circulation circuit 7 of the dielectric fluid.

[0043] In a non-limiting exemplary embodiment, the cooling circuit 12 includes: • a device 13 for cooling the dielectric fluid, this cooling device 13 being able to be formed by a heat exchanger; • a reservoir 14 of dielectric liquid; • means 15, 16 for pressurizing the dielectric fluid, the pressurizing means 15, 16 comprise: • low pressure pressurization means 15 arranged to pressurize the dielectric fluid at low pressure, • high pressure pressurization means 16 arranged to pressurize the dielectric fluid at high pressure, and • bypass means 17 allowing the high pressure pressurization means 16 to be short-circuited.

[0044] In the example illustrated, the low pressure pressurization means 15 are formed by a low pressure pump and the high pressure pressurization means 16 are formed by a high pressure pump.

[0045] In an exemplary embodiment not illustrated, the pressurization means are formed by a two-stage pump, a first stage forming the low-pressure pressurization means and the other stage forming the high-pressure pressurization means.

[0046] [fig.3] illustrates another embodiment of the invention in which the high-pressure pressurization means 16 are arranged in the circulation circuit 7 of the dielectric fluid, in other words in the receptacle 5. Such an arrangement makes it possible to reduce the size of the battery pack 1.

[0047] Thus, during normal operating life situations of the battery pack 1, the cells 3 which are held by the side members 4 are semi-immersed in the circulation circuit of the dielectric fluid 7. The low-pressure pump 15 is activated and the bypass means 17 short-circuit the high-pressure pump 16 so as to circulate the dielectric fluid without spraying it. Thus, the lower parts of the cells 3, which are immersed in the dielectric fluid circulating in the circulation circuit 7, are cooled via direct contact with the dielectric fluid.

[0048] During life situations of high demand on the cells 3 with a request for rapid recharging or discharging, in extreme climatic conditions, when driving on the motorway or in the case where there is thermal runaway, the spray function is activated by means of the high pressure pump 16 which will pressurize the dielectric fluid at high pressure to spray it via the spraying means 9 of the side members 4 to spray the faces of the juxtaposed cells 3 and possibly the electrical bus bars for the electrical connection of the cells 3.

[0049] Thus, it is possible to quickly cool the battery pack 1 via direct spraying of the dielectric fluid onto the faces of the cells 3 without impacting the height of the battery pack 1 and also prevent the occurrence of thermal runaway phenomenon in battery 1.

[0050] [Fig.4] illustrates a top view of three side members 4a, 4b, 4c arranged between four rows 2a, 2b, 2c, 2d of cells.

[0051] More particularly, the rows 2a and 2b of cells are juxtaposed to the spar 4a, the rows 2b and 2c of cells are juxtaposed to the spar 4b and the rows 2c and 2d of cells are juxtaposed to the spar 4c.

[0052] In this exemplary embodiment, • the spraying means 9 of the spar 4a are aligned in a row rl, • the spraying means 9 of the spar 4b are aligned in a row rl, and • the spraying means 9 of the spar 4c are arranged alternately on two rows rl and r2.

[0053] On the spar 4a, each spraying means 9 is arranged to spray the dielectric fluid onto one of the two rows 2a, 2b of cells juxtaposed to the spar 4a. More particularly, the spraying means 9 are arranged to spray the dielectric fluid alternately onto one row 2a of cells then onto the other row 2b of cells.

[0054] On the spar 4b, each spraying means 9 is arranged to spray the dielectric fluid onto the two rows 2b, 2c of cells juxtaposed to the spar 4b.

[0055] On the spar 4c, each spraying means 9 is arranged to spray the dielectric fluid onto one of the two rows 2c, 2d of cells juxtaposed to the spar 4c. More particularly, each of the spraying means 9 is arranged to spray the dielectric fluid onto the furthest juxtaposed row of cells 2c, 2d.

[0056] [Fig. 5] illustrates a method 100 for cooling a battery pack 1 according to one of the aforementioned aspects of the invention. The battery pack 1 is arranged in a vehicle 18 provided with means 19 for measuring the temperature of the battery pack 1 and a cooling management computer 20.

[0057] The method 100 comprises, when the temperature of the battery pack 1 exceeds a threshold value, a step of triggering 101, via the cooling management computer 20, a high-pressure circulation of the dielectric fluid in the circulation circuit 7 of the dielectric fluid. Thus, the dielectric fluid is sprayed onto the rows 2 of cells 3. In other words, during this step 101, the high-pressure pump 16 is activated so as to increase the pressure in the circulation circuit 7 until the dielectric fluid is ejected via the spraying means 9 onto the rows 2 of cells 3.

[0058] It is understood that a person skilled in the art is able to make modifications, in particular with regard to the arrangement of the spraying means and extraction of the dielectric fluid.

Claims

Claims

1. Battery pack (1) comprising a plurality of rows (2) of cells (3), side members (4) arranged between said rows (2) of cells (3), a receptacle (5) receiving said plurality of rows (2) of cells (3) and said side members (4), and means (6) for cooling said cells (3), said battery pack (1) being characterized in that said means (6) for cooling said cells (3) comprise: - a circulation circuit (7) for a dielectric fluid arranged in a bottom (8) of said receptacle (5) and in a thickness of said side members (4), - means (9) for spraying said dielectric fluid onto said rows (2) of cells (3), said spraying means (9) passing through an upper surface (10) of said side members (4) and communicating with said circulation circuit (7),- extraction means (11) of said sprayed dielectric fluid passing through said upper surface (10) and opening into said circulation circuit (7), and - a cooling circuit (12) of said dielectric fluid connected to said circulation circuit (7).,

2. Battery pack (1) according to the preceding claim characterized in that, on a side member (4), the spraying means (9) are aligned in a row (rl).

3. Battery pack (1) according to claim 1 characterized in that, on a side member (4), the spraying means (9) are arranged alternately in two rows (rl, r2).

4. Battery pack (1) according to any one of the preceding claims, characterized in that, on a spar (4), each spraying means (9) is arranged to spray the dielectric fluid onto one of the two rows (2) of cells (3) juxtaposed to said spar (4).

5. Battery pack (1) according to any one of claims 1 to 3 characterized in that, on a spar (4), each spraying means (9) is arranged to spray the dielectric fluid onto two rows (2) of cells (3) juxtaposed to said spar (4).

6. Battery pack (1) according to any one of the preceding claims characterized in that the spraying means (9) are formed by: - ​​orifices provided in the side members (4), - calibrated valves arranged in the side members (4), or - adjustable nozzles.

7. Battery pack (1) according to any one of the preceding claims, characterized in that the extraction means (11) are formed by one-way valves.

8. Battery pack (1) according to any one of the preceding claims, characterized in that the cooling circuit (12) comprises a device (13) for cooling the dielectric fluid and means (15, 16) for pressurizing said dielectric fluid, said pressurizing means (15, 16) comprising: - low pressure pressurizing means (15) arranged to pressurize the dielectric fluid at low pressure, and - high pressure pressurizing means (16) arranged to pressurize the dielectric fluid at high pressure.

9. Battery pack (1) according to the preceding claim, characterized in that the high pressure pressurization means (16) are arranged in the circulation circuit (7).

10. Method (100) for cooling a battery pack (1) according to any one of the preceding claims, said battery pack (1) being arranged in a vehicle (18) provided with means (19) for measuring the temperature of the battery pack (1) and a cooling management computer (20), said method (100) comprising, when the temperature of the battery pack (1) exceeds a threshold value, a step of triggering (101), via said cooling management computer (20), a high-pressure circulation of the dielectric fluid in the circulation circuit (7) of the dielectric fluid so as to spray said dielectric fluid onto said rows (2) of cells (3).

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