Electric vehicle battery thermal management device

1. A device for the thermal management of a battery of electric accumulators assembled within a rigid casing, said device comprising:

thermal storage means integrated with said battery, the thermal storage means including:

a chamber containing a phase-change material and having a volume for exchange of heat with said accumulators which is delimited by at least part of said rigid casing, the melting of the phase-change material being able to store heat, and the solidification of the phase-change material being able to release the heat previously stored, and

an expansion vessel, at a distal end of said chamber, able to absorb expansions of said phase-change material as the phase-change material changes phase,

wherein an upper wall made of a heat-conducting material, which is formed by said at least one part of said rigid casing, forms a first surface for exchange of heat with said accumulators,

wherein none of said accumulators are inside said chamber,

wherein the rigid casing and the upper wall of said chamber are between said accumulators and the volume for exchange of heat,

wherein said upper wall is entirely below the accumulators and supports a bottom face of the battery, and

wherein said first surface covers an entirety of the bottom face of the battery.

2. The device as claimed in claim 1 , wherein said expansion vessel is raised relative to said chamber and has an internal volume extending the volume for exchange of heat of said chamber from a lower end of said expansion vessel to an upper closed end of said expansion vessel, which is opposite said lower end.

3. The device as claimed in claim 1 , wherein an interior of said expansion vessel is in communication with an exterior by means of a channeling open to ambient air, said channeling being arranged in an upper part of said expansion vessel.

4. The device as claimed in claim 3 , wherein said channeling open to the ambient air is connected to a conduit able to raise a connection to the ambient air.

5. The device as claimed in claim 1 , wherein a lower wall made of a heat-conducting material is disposed opposite said upper wall so as to close the volume for exchange of heat, said lower wall forming a second surface for exchange of heat with an exterior of said battery.

6. The device as claimed in claim 5 , wherein said chamber includes heat exchange fins integrated on the first surface of said upper wall of said chamber and on the second surface of said lower wall of said chamber.

7. The device as claimed in claim 1 , further comprising an active cooling system including a cooling circuit installed in said battery, equipped with means for circulating a cooling fluid through said battery.

8. The device as claimed in claim 7 , wherein the active cooling system further includes control means, said control means controlling activation of said active cooling system when a temperature of said accumulators reaches a first temperature threshold (threshold 1 ) greater than a melting point of said phase-change material and able to control the stopping of said active cooling system when the temperature of said accumulators reaches a second temperature threshold (threshold 2 ) between the melting point of said phase-change material and said first threshold (threshold 1 ).

9. The device as claimed in claim 1 , wherein the melting point of said phase-change material is approximately 35° C.

10. The device as claimed in claim 1 , wherein said phase-change material is or includes paraffin.