Search

EP-4396459-B1 - ELASTOCALORIC ELEMENT FOR A TEMPERATURE CONTROL SYSTEM

EP4396459B1EP 4396459 B1EP4396459 B1EP 4396459B1EP-4396459-B1

Inventors

  • Schneck, Christian
  • OLFE, Jürgen

Dates

Publication Date
20260513
Application Date
20220719

Claims (10)

  1. Elastocaloric element (1) for a temperature control system (4), wherein the elastocaloric element (1) has an elastic carrier (2) and a coating (3) applied to the carrier (2), wherein the carrier (2) is at least partially made of a plastics material and the coating (3) is at least partially made of an elastocaloric material.
  2. Element (1) according to claim 1, wherein the coating (3) has a layer thickness of up to 200 µm.
  3. Element (1) according to claim 1 or claim 2, wherein the coating (3) has a layer thickness in the range of 5 µm to 100 µm.
  4. Element (1) according to any of the preceding claims, wherein the carrier (2) is reversibly stretchable up to a yield strength of at least 2%.
  5. Element (1) according to any of the preceding claims, wherein the elastocaloric material is a shape-memory alloy.
  6. Element (1) according to any of the preceding claims, wherein the carrier (2) is in the form of a carrier body having a cross section that is at least predominantly constant.
  7. Element (1) according to any of the preceding claims, wherein the carrier (2) has an annular, star-shaped or cross-shaped cross section.
  8. Element (1) according to any of the preceding claims, wherein the carrier (2) is in the form of a spring.
  9. Temperature control system (4) comprising an elastocaloric element (1) according to any of the preceding claims.
  10. Motor vehicle (5) comprising a temperature control system (4) according to claim 9.

Description

The invention relates to an elastocaloric element for a temperature control system, a temperature control system and a motor vehicle with a temperature control system. The elastocaloric effect, which typically causes a reversible temperature change through cyclic deformation of an elastocaloric material in the strain range of 1%–5% (compression or tension), can be used technically for temperature control. The elastocaloric material heats up when compressed and cools back down to its original temperature when subsequently stretched. By cyclically dissipating the heat from the elastocaloric material, this effect can be used for temperature control, particularly air conditioning in the form of cooling or heating. Elastocaloric materials are metal alloys with an elastocaloric effect, which naturally have a high modulus of elasticity and are therefore relatively stiff, which is why large forces, moments or electrical currents usually have to be applied to achieve a technically usable effect in the form of sufficiently high thermal power. To achieve high thermal performance with minimal use of elastocaloric material, the surface area of the elastocaloric material should be as large as possible to dissipate heat to the environment as quickly as possible. If the heat is dissipated quickly, the system frequency of the temperature control system can be set high. Known solutions for the cyclic operation of the elastocaloric material exist for tensile and compressive loads. In the case of operating the elastocaloric material under tensile stress, solutions exist with thin wires as elastocaloric elements, which are made from the elastocaloric material. Such a solution is used, for example, in US 2020/0088449 A1 described. The wires can be designed to ensure sufficiently rapid heat dissipation, requiring very small wire diameters of 200 µm. The wires are typically operated at system frequencies of less than 1 Hz and achieve in Current prototypes achieve a thermal output of approximately 250 with a material quantity of 50 g. To achieve a cooling/heating capacity of 5 kW and more, as required particularly in automotive applications, a correspondingly large number of wires (> 1000) is needed. Further disadvantages include the low durability of the wires and their limited robustness against tolerances, vibrations, and temperature fluctuations. In the case of operating the elastocaloric material under compressive stress, prior art solutions exist using hollow rods as elastocaloric elements, manufactured from the elastocaloric material. Due to the compressive stress, this offers the advantage of increased durability. At the same time, the elastocaloric material must be used not only for heat generation but also for the stabilizing shape, so the rods must have a sufficiently thick wall to prevent buckling under compressive stress. The greater wall thickness compared to the wire solution results in slower heat dissipation from the elastocaloric material, meaning that higher frequencies can only be achieved with reduced efficiency. Consequently, the material requirement for this variant is higher. Out of WO 2019/166251 A1 A hybrid approach for an elastocaloric element is known. The elastocaloric element described there consists of three layers, with a middle layer being designed as a spring sheet and the layers surrounding the middle layer being made of different elastocaloric materials with a layer thickness of 225 µm each. Furthermore, the document states US2011/0049130 A1 Another elastocaloric element for a temperature control system is known. In one embodiment, it consists of an elastomer that encloses a heating element and is in contact with a layer of a shape-memory alloy material. Furthermore, the document states DE 100 65 550 A1 a composite body with a thermoelastic polymer is known. The object of the present invention is to reduce the disadvantages of the elastocaloric elements known from the prior art, in particular to provide an elastocaloric element which has a high durability under cyclic loading, offers an increased operating frequency and improved heat transfer when used in a temperature control system, and has a low requirement for elastocaloric material. The aforementioned problem is solved by the subject matter of the patent claims, in particular by an elastocaloric material according to claim 1, a temperature control system according to claim 9. and a motor vehicle according to claim 10. Further advantages and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details disclosed in connection with the elastocaloric material according to the invention naturally also apply in connection with the temperature control system and the motor vehicle according to the invention, and vice versa, so that the disclosures relating to the individual aspects of the invention are always, or can always be, mutually referenced. According to a first aspect, the