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EP-4564526-B1 - BATTERY SYSTEM WITH COOLING CIRCUIT

EP4564526B1EP 4564526 B1EP4564526 B1EP 4564526B1EP-4564526-B1

Inventors

  • Ipek, Eymen

Dates

Publication Date
20260506
Application Date
20231129

Claims (15)

  1. A battery system (100), comprising: a plurality of battery cells (10) accommodated in a housing (12); a cooling circuit (20) comprising a cooling channel (26) and configured to conduct a coolant through the cooling channel (26), wherein the coolant is in thermal contact with at least a portion of the plurality of battery cells (10) while flowing through the cooling channel (26); an eddy current heater (30) comprising a ferrous material (40), wherein the eddy current heater (30) is configured to heat the ferrous material (40) by inducing eddy currents in the ferrous material (40) and to transfer heat to the coolant in the cooling channel (26); characterized in that , the ferrous material (40) is disposed inside at least a portion of the cooling channel (26) and/or surrounds at least a portion of the cooling channel (26).
  2. The battery system (100) according to claim 1, wherein the ferrous material (40) comprises an inner ferrous coating (42) which is attached to at least a portion of an inner surface (28) of the cooling channel (26).
  3. The battery system (100) according to any one of the claims 1 to 2, wherein the ferrous material (40) comprises at least one inner ferrous hollow body (44) disposed inside the cooling channel (26) to cover an inner surface (28) of the cooling channel (26).
  4. The battery system (100) according to claim 3, wherein the inner ferrous hollow body (44) comprises at least one of an inner hollow cylinder (44a) and an inner ring (44b).
  5. The battery system (100) according to any one of the preceding claims 2 to 4, wherein the ferrous material (40) comprises a flat inner surface (41).
  6. The battery system (100) according to one of the claims 2 to 4, wherein the ferrous material (40) comprises a corrugated inner surface (49) configured to increase the surface area with the coolant.
  7. The battery system (100) according to claim 6, wherein the corrugated surface (49) comprises a plurality of ridges (43).
  8. The battery system (100) according to any one of the claims 1 to 7, wherein the ferrous material (40) comprises an outer ferrous coating (46) attached to at least a portion of an outer surface (29) of the cooling channel (26).
  9. The battery system (100) according to any one of the claims 1 to 8, wherein the ferrous material (40) comprises at least one outer ferrous hollow body (47) surrounding at least a portion of the cooling channel (26) to cover an outer surface (29) of the cooling channel (26).
  10. The battery system (100) according to one of the claims 1 to 9, wherein the ferrous material (40) is arranged at a coolant inlet (22) for the cooling channel (26) at a periphery of the housing (12) and/or is extending from the coolant inlet (22) along the cooling channel (26).
  11. The battery system (100) according to one of the claims 10, wherein the ferrous material (40) is arranged at a coolant outlet (24) of the cooling channel (26) at a periphery of the housing (12) and/or is extending to the coolant outlet (24) along the cooling channel (26).
  12. The battery system (100) according to any one of the preceding claims 1 to 11, wherein the cooling channel (26) is made of a non-ferrous material.
  13. The battery system (100) according to any one of the preceding claims 1 to 12, wherein the eddy current heater (30) comprises a heating coil (32) and a charging circuit (36) connected with the heating coil (32) through AC power lines (34) to cause, when being operated, the heating coil (32) to induce eddy currents in the ferrous material (40).
  14. A vehicle comprising the battery system (100) according to any one of the preceding claims 1 to 13.
  15. A method of heating a plurality of battery cells (10) of a battery system (100), wherein the method comprises the steps of: a) providing (S100) a battery system (100) as defined according to any of the claims 1 to 13; b) heating (S200) at least a portion of the plurality of battery cells (10) of the battery system (100) by inducing eddy currents in the ferrous material (40) through operating of the eddy current heater (30).

Description

Field of the Disclosure The present disclosure relates to a battery system with a coolant circuit. The present disclosure further deals with a vehicle comprising the battery system. In addition, the present disclosure refers to a method of heating battery cells of a battery system. Technological Background Recently, vehicles for transportation of goods and peoples have been developed that use electric power as a source for motion. Such an electric vehicle is an automobile that is propelled by an electric motor using energy stored in rechargeable batteries. An electric vehicle may be solely powered by batteries or may be a hybrid vehicle powered by for example, a gasoline generator or a hydrogen fuel power cell. A hybrid vehicle may include a combination of an electric motor and conventional combustion engine. Generally, an electric-vehicle battery (EVB, or traction battery) is a battery used to power the propulsion of battery electric vehicles (BEVs). Electric-vehicle batteries differ from starting, lighting, and ignition batteries in that they are designed to provide power for sustained periods of time. A rechargeable (or secondary) battery differs from a primary battery in that it is designed to be repeatedly charged and discharged, while the latter is designed to provide an irreversible conversion of chemical to electrical energy. Low-capacity rechargeable batteries are used as power supplies for small electronic devices, such as cellular phones, notebook computers and camcorders, while high-capacity rechargeable batteries are used as power supplies for electric and hybrid vehicles and the like. Battery modules can be constructed either in a block design or in a modular design. In the block design, each battery is coupled to a common current collector structure and a common battery management system and the unit thereof is arranged in a housing. In the modular design, pluralities of battery cells are connected together to form submodules, and several submodules are connected together to form the battery module. In automotive applications, battery systems generally include a plurality of battery modules connected together in series to provide a desired voltage. The battery modules may include submodules with a plurality of stacked battery cells, and each stack includes cells connected in parallel that are, in turn, connected in series (XpYs) or cells connected in series that are, in turn, connected in parallel (XsYp). To provide thermal control of the battery pack a thermal management system is required to safely use the at least one battery module by efficiently emitting, discharging, and/or dissipating heat generated from its rechargeable batteries. If the heat emission, discharge, and/or dissipation is not sufficiently performed, temperature deviations may occur between respective battery cells, such that the at least one battery module may no longer generate a desired (or designed) amount of power. In addition, an increase of the internal temperature can lead to abnormal reactions occurring therein and thus charging and discharging performance of the rechargeable battery deteriorates and the lifespan of the rechargeable battery is shortened. Thus, cell cooling for effectively dissipating heat from the battery cells is required. Usually, a battery system includes a cooling circuit for thermal management. The battery system, in particular for automotive applications, is sensitive to environmental conditions and in particular to temperature. Low temperatures of the battery cells for example during charging may lead to weak performance and reduced lifetime. Therefore, a pre-heating of the battery may be desirable to provide better performance for example during charging and extend lifetime. Despite of that an electrical current flow can increase a temperature of a battery, even with this additional heat said charging at cold temperatures still remains a critical problem. An additional heater is required to allow reliable a pre-heating of the battery. According to the state of the art, resistance heaters including a resistor with a voltage applied thereto are used either as foils between the cells or attached on the outside of a cooling plate. In such configuration heat has to be transferred from the resistance heaters to a coolant via the material of the cooling plate. This is however a slow form of heating which involves a lag time to reach a sufficient and desired temperature. The prior art CN 116 505 138 A discloses a battery using induction heating, wherein a hollow wire is provided on the battery and liquid cooling medium can flow through the hollow wire while being connected to a cooling system. The WO 2022/255099 A1 discloses a hollow coil for each battery cell through which a current passes through. The hollow coil is connected to a duct of the battery module by one end reaching into the duct so that cooling gas can be forcibly introduced to the inside of the hollow coil. In establishing an improv