ELECTRIC OR HYBRID MOTOR VEHICLE FEATURING A BATTERY CELL THERMAL PROTECTION DEVICE

Abstract

The invention relates to an electric or hybrid motor vehicle, comprising at least one battery pack comprising at least one electrical module itself comprising at least one battery cell (12), and comprising at least one thermal protection device (2) for the thermal protection of the battery cell, characterized in that said thermal protection device (2) comprises at least one electrostatic particle filter (20), implanted in said electrical module, or in said battery cell (12), and which is arranged to capture particles (7) emanating from said battery cell (12) during a thermal runaway event, in order to prevent the diffusion of said particles (7) from the interior of said cell (12) to the rest of said motor vehicle. Figure 3

Description

Title of the invention: ELECTRIC OR HYBRID MOTOR VEHICLE COMPRISING A BATTERY CELL THERMAL PROTECTION DEVICE

[0001] The invention relates to an electric or hybrid motor vehicle, comprising at least one battery pack comprising at least one electrical module itself comprising at least one battery cell, and comprising at least one thermal protection device for the thermal protection of the battery cell.

[0002] The invention relates to the field of electric traction for automobiles, and in particular to electric traction batteries, as well as to appropriate safety devices for the prevention and treatment of thermal runaway which may occur in the life cycle of the vehicle.

[0003] It is known in the prior art that battery pack thermal protectors, which are fixed under the pack cover, are designed to resist thermal runaway of the battery pack following a shock, thermal event, or other incident. While this solution addresses the issue of thermal protection for occupants, it does not provide adequate protection during a thermal runaway, particularly regarding the diffusion of dust and particles present in the battery pack into the rest of the vehicle.

[0004] This problem of the presence of volatile particles is important because particles can cause malfunctions on other elements, particularly electrical ones, present in or near the battery pack.

[0005] The objective of the present invention is to remedy these drawbacks by proposing a simple and effective prevention solution, by adding a complementary device to be implanted on the battery cells, or even the complete cell module, for treatment at the source of the problem.

[0006] To achieve this objective, the invention proposes an electric or hybrid motor vehicle, comprising at least one battery pack comprising at least one electrical module itself comprising at least one battery cell, and comprising at least one thermal protection device for the thermal protection of the battery cell.

[0007] According to the invention, said thermal protection device comprises at least one particle electrostatic precipitator, implanted in said electrical module, or in said battery cell, and which is arranged to capture particles emanating from said battery cell during a thermal runaway event, in order to prevent the diffusion of said particles from the interior of said cell to the rest of said motor vehicle.

[0008] Thus the invention protects the vehicle's components, and in particular the electrical or electronic components, against a flow of particles from a battery cell during a thermal runaway.

[0009] Advantageously, at least one of said cells comprises a vent, which is an overpressure vent, arranged to open when the pressure in said cell exceeds a predetermined threshold and when the temperature in said cell exceeds a predetermined threshold, during a thermal runaway, said vent being arranged so that, in its open position, it allows passage of said particles expelled by said cell under high temperature and pressure characteristic of said thermal runaway, towards a mica cone, which is comprised of said thermal protection device at the outlet of said vent and which is arranged to resist the temperature rise and to concentrate a primary jet of gas and particles in the same axial direction towards an outlet stack, and said particle electrostatic precipitator comprises, on the one hand, upstream of said stack, a negatively charged grid arranged in said mica cone frontally with respect to said primary jet,and which is arranged to allow passage of gases and said particles and to negatively charge them, and on the other hand, downstream of said mica cone, a positive pole arranged in the upper part of said chimney, opposite said cell, and which is arranged to peripherally deflect said particles from an axial gas flow.

[0010] The electrostatic filter ensuring the capture of particles is reliable, it ensures effective safety at a low or moderate cost.

[0011] Advantageously, said cell is surrounded by a cell housing, in which said vent is pre-cut.

[0012] Thus the arrangement of the vent is inexpensive, and does not require a complex mechanism for its opening.

[0013] Advantageously, said mica cone is surrounded externally by a chamber forming a reservoir, closed on the side of said cell and open on the side of said chimney at the outlet of said mica cone, and comprising a deflector penetrating into said chimney and arranged to separate a secondary axial flow of gas and a peripheral flow of said particles.

[0014] This prevents recirculation of the particles by isolating them after their ejection from the battery cell.

[0015] Advantageously, said chamber is internally delimited by an internal partition, contiguous or merging with said mica cone, and an external partition, which also forms an upper exit structure of said chimney, opposite said cell.

[0016] The inner partition of the chamber can thus be formed from the exterior of the mica cone, and does not require any additional component; similarly the partition

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[0024] externally forms a chimney bell, and the thermal protection device can be limited to six components: the vent, the grid and the positive pole together forming the electrostatic filter, the mica cone, the chimney, and the deflector. Advantageously, said motor vehicle includes at least one automatic extinguishing device using inert gas or inhibitory agents, to treat and extinguish the flames of a secondary axial flow of gas exiting said chimney. The treatment of flaming gases is thus carried out after the capture of incandescent particles. Advantageously, said motor vehicle includes said thermal protection device comprising said electro-particle filter, opposite each said vent of each said cell comprising said battery pack. The moderate cost of the thermal protection device according to the invention makes it preferable to install it on each battery cell. Advantageously, said motor vehicle includes said thermal protection device comprising said electro-particle filter, is arranged to protect bus bars comprising said battery pack. Since the bus bars are the components closest to the battery cells, they are well protected against a flow of particles during a thermal runaway. The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.1] schematically illustrates a motor vehicle according to the invention, comprising a battery pack with several electrical modules, each comprising a battery cell, and a thermal protection device for the latter; - [Fig.2] schematically illustrates such an electrical module, comprising a battery cell, and a thermal protection device, in a thermal runaway configuration; - [Fig.3] schematically illustrates the details of this protective device thermal, in the configuration of [Fig.2]; a flow of burning gases and particles exits the battery cell through a vent made for this purpose, is guided into a mica cone which concentrates it in an axial direction, passes through a negatively charged grid which includes a particle electrofilter, before joining a chimney in which a positive pole, which also includes this same particle electrofilter, attracts them, and a deflector channels the particles as they fall back into a reservoir, in which the particles remain enclosed. A 1000 electric motor vehicle is schematically illustrated in [Fig. 1] or hybrid, comprising at least one battery pack 100, comprising at least one electrical module 10 itself comprising at least one battery cell 12, and comprising at least one thermal protection device 2 for the thermal protection of the battery cell. The battery pack 100 generally comprises several electrical modules 10, often grouped in columns, and each electrical module 10 generally comprises several cells 12.

[0025] According to the invention, and as shown in [Fig. 2] and [Fig. 3], this thermal protection device 2 comprises at least one particle electrostatic precipitator 20, implanted in such an electrical module 10, or in such a battery cell 12, and which is arranged to capture particles 7 emanating from at least one battery cell 12 during a thermal runaway event, in order to prevent the diffusion of such particles 7 from inside a cell 12 to the rest of the vehicle 1000, in particular to its electrical circuits and any fuel circuits. Such a thermal runaway event is exceptional in the life of a vehicle, and is most often linked to an accident such as a collision, but protective means must be permanently installed, even if never activated, such as automatic fire suppression systems using inert gas or inhibitory agents, or other devices.

[0026] At least one cell 12, and more particularly each cell 12, includes a vent 11. More particularly, the cell 12 is surrounded by a cell housing 121, in which this vent 11 is pre-cut. This vent 11 is an overpressure vent, which is arranged to open when the pressure in the cell 12 exceeds a predetermined threshold, which is the case when the temperature in the cell 12 exceeds a predetermined threshold, during a thermal runaway.

[0027] When vent 11 is open, it allows the passage of numerous particles 7 expelled from cell 12 under high temperature and pressure. These particles may consist of metallic elements or metallic alloys, in particular copper, aluminum, or other, anode debris, or other materials; these particles may cause electrical and / or thermal malfunctions, particularly with electrical bus bars 6 included in the electrical module 10 and / or the battery pack 100.

[0028] The thermal protection device 2 is preferably fixed directly to the vent outlet of the cell 12, or to the vent outlet of the electrical module 10, as applicable. Arranging the thermal protection device 2 at the vent outlet of the cell 12 logically provides the best efficiency, with immediate responsiveness, and is described in more detail below.

[0029] During a thermal runaway of the cell 12, the film of the cell 12 opens, and through the vent 11 exits a flow of flames and particles 7 driven by the pressure.

[0030] The thermal protection device 2 comprises a mica cone 5, which is arranged in outlet of vent 11, and is arranged to resist the temperature rise and to concentrate a primary jet 9 of gas and particles 7 along the same axial direction.

[0031] The particle electrofilter 20 comprises a negatively charged grid 8 arranged in the mica cone 5 frontally to the outgoing flow of the cell 12. The gases and particles 7 then pass through this negatively charged grid 8.

[0032] The mica cone 5 is surrounded externally by a chamber 25 forming a reservoir, closed on the side of the cell 12 and open on the side of a chimney 41 at the outlet of the mica cone 5. This chamber 25 is delimited internally by an inner partition 22, in particular contiguous with or coinciding with the mica cone 5, and an outer partition 21, which also forms an upper outlet structure of the chimney 41, opposite the cell 12. The chamber 25 includes a deflector 4 penetrating the chimney 41, this deflector 4 being arranged to separate an axial flow of gas and a peripheral flow of particles 7.

[0033] The negatively charged particles 7 are drawn into the chimney 8 by a positive pole 3, which comprises the particle electrofilter 20, and which is arranged in the upper part of the chimney 41, opposite the cell 12, and when they fall back down, the deflector 4 then channels them into the reservoir of the chamber 25, in which the particles 7 remain enclosed. Thus, a maximum of particles 7 are captured as soon as they exit by this particle electrofilter 20, which protects the passage of the omnibus bars 6. A secondary flow 1 of gas, less loaded with particles than the primary jet 9, or even clean, leaves axially the chimney, opposite the cell 12. It is then possible to intervene at least one conventional automatic extinguishing device with inert gas or inhibitor agents, which is included in the vehicle 1000, to treat the flames and extinguish them, without damage to the installations of the vehicle 1000.

[0034] More specifically, opposite each vent 11 of each battery cell 12, such a filtering device for particles emitted by polarization of walls constituting an electrostatic filter is installed. It is understood that this is a thermal protection device for the vehicle's components against particles originating from inside the battery compartment, and not the other way around.

[0035] The use of an electrostatic precipitator to protect vehicle components from particles originating in the battery pack is novel, as such an electrostatic precipitator is generally used for filtering gases, for example, chimney gases or exhaust gases from an internal combustion engine. Prior art involves collecting gases from battery pack cells through an ordinary filter, but this filter is not electrostatic and therefore cannot have any particular effect on the particles.

[0036] Such an electrostatic filter can either be specific to each cell as described above, or be common to several cells or even to all the cells in the pack battery. No prior art provision suggests the use of an electrostatic filter to protect vehicle components from particles originating from inside the battery pack.

[0037] In summary, the invention allows for an efficient treatment of the problem at its source. The proposed solution can be processed column by column, for treatment of the entire module. The particles are stored outside of any surrounding electrical circuit.

[0038] The invention represents a real advance over any regulation relating to the treatment of dust and fumes during a vehicle thermal runaway.

Claims

Claims

1. An electric or hybrid motor vehicle (1000), comprising at least one battery pack (100) comprising at least one electrical module (10) itself comprising at least one battery cell (12), and comprising at least one thermal protection device (2) for thermal protection of the battery cell, characterized in that said thermal protection device (2) comprises at least one particle electrostatic precipitator (20), installed in a said electrical module (10), or in such a said battery cell (12), and which is arranged to capture particles (7) emanating from a said battery cell (12) during a thermal runaway phenomenon, to prevent the diffusion of said particles (7) from the interior of said cell (12) towards the rest of said motor vehicle (1000).

2. Motor vehicle (1000) according to claim 1 characterized in that at least one said cell (12) comprises a vent (11), which is an overpressure vent, arranged to open when the pressure in said cell (12) exceeds a predetermined threshold and when the temperature in said cell (12) exceeds a predetermined threshold, during thermal runaway, said vent (11) being arranged to, in its open position, allow passage to said particles (7) expelled by said cell (12) under high temperature and pressure characteristic of said thermal runaway, towards a mica cone (5), which comprises said thermal protection device (2) at the outlet of said vent (11) and which is arranged to resist the rise in temperature and to concentrate a primary jet (9) of gas and particles (7) in the same axial direction towards an outlet chimney (41), and in that said particulate electrostatic precipitator (20) comprises, of a part,upstream of said chimney (41), a negatively charged grid (8) arranged in said mica cone (5) frontally with respect to said primary jet (9), and which is arranged to be crossed by the gases and said particles (7) and to charge them negatively, and on the other hand, downstream of said mica cone (5), a positive pole (3) arranged in the upper part of said chimney (41), opposite said cell (12), and which is arranged to peripherally separate said particles (7) from an axial gas flow.,

3. Motor vehicle (1000) according to claim 2 characterized in that said cell (12) is surrounded by a cell housing (121), in which said vent (11) is pre-cut.

4. Motor vehicle (1000) according to claim 2 or 3 characterized in that said mica cone (5) is surrounded externally by a chamber (25) forming a reservoir, closed on the side of said cell (12) and open on the side of said chimney (41) at the outlet of said mica cone (5), and comprising a deflector (4) penetrating into said chimney (41) and arranged to separate a secondary axial flow (1) of gas and a peripheral flow of said particles (7).

5. Motor vehicle (1000) according to claim 4 characterized in that said chamber (25) is delimited internally by an internal partition (22), adjoining or merging with said mica cone (5), and an external partition (21), which also forms an upper outlet structure of said chimney (41), opposite said cell (12).

6. Motor vehicle (1000) according to one of claims 2 to 5, characterized in that said motor vehicle (1000) comprises at least one automatic extinguishing device using inert gas or inhibiting agents, for treating the flames of a secondary axial flow (1) of gas leaving said chimney (41) and extinguishing them.

7. Motor vehicle (1000) according to one of claims 2 to 6 characterized in that said motor vehicle (1000) comprises a said thermal protection device (2) comprising a said particle electrofilter (20), opposite each said vent (11) of each said cell (12) which said battery pack (100) comprises.

8. Motor vehicle (1000) according to one of claims 1 to 6 characterized in that said motor vehicle (1000) comprises a said thermal protection device (2) comprising a said particle electrostatic precipitator (20), is arranged to protect bus bars (6) which comprise said battery pack (100).

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