DE4226781A1 - Heating circuit for inside of electric car - pumps fluid heated by driving motor with header tank and fan - Google Patents

Abstract

Heat from the driving motor and heat sinks of electronic control apparatus, is extracted. A fan can direct this either into the atmosphere or into the car's interior. The heating medium is pumped around the circuit which need not include the driving motor if a valve in a by-pass pipe is opened. A header tank is provided for the fluid and an immersion-type heater for additional heating if necessary. The battery temperature be raised to absorb short-term heat peaks from the motor, e.g. which can then be disseminated through the heating circuit with the help of a heat exchanger. ADVANTAGE - Uses waste heat.

Description

The invention relates to a heat transfer circuit Electric vehicle, the liquid heat transfer medium from the vehicle drive unit and / or from cooling the additional elements absorbs heat and in a cooling heat Meters to one in the vehicle interior and / or in releases air flowing into the environment. Furthermore be the invention meets an operating method for one of the like heat transfer circuit.

While from DE-OS 24 51 221 an air heater for a Electric vehicle is known that the waste heat of the driving direct drive unit for heating the vehicle Uses the interior, simulates a heat transfer circuit the preamble of claim 1 with a liquid heat medium at least internal state of the art. Such a heat transfer circuit with regard to To improve the heat balance of the individual components, is the object of the present invention.

To solve this problem it is provided that the heat transfer medium circuit via a battery heat exchanger which is inserted into a vehicle Fluid circuit flowing through the battery is integrated, and via a vehicle drive electric motor and / or  leads to the electric motor via a bypass and / or one Heat exchanger for the additional elements to be cooled flows.

A solution to the further task, an energetic one partial operating method for such heat To show carrier cycle is that the Tem temperature of the battery temporarily at least slightly above the normal battery operating temperature is raised, to thereby, if necessary, via the battery heat exchanger to heat the heat transfer medium. The other claims have advantageous further training to the content.

A component of the vehicle drive unit is next to a vehicle battery to the vehicle drive electric motor yelled. In particular, this battery is a sodium-sulfur battery, its optimal operation temperature is relatively high and by appropriate measure took at this temperature. Because of the heat Carrier cycle of the electric vehicle u. a. due to the high battery operating temperature this battery can be run is a separate, fluid circuit flowing through the battery is provided, which via a battery heat exchanger with the heat transfer circuit is in heat-transferring connection. There against can a vehicle drive electric motor directly from Heat transfer circuit to be cooled. However, it should after starting the electric vehicle, if one rapid heating of the vehicle interior is desirable is, the still cold electric motor is not from the heat transfer medium circuit are flowed through, on the one hand a high To achieve heating power and on the other hand the Elektromo not to heat the gate additionally. According to the invention a bypass to the electric motor is therefore provided. This Bypass can be switched easily or in the sense of an indi visual regulation by means of a volume distribution valve  can also be acted upon parallel to the electric motor. Around for a comfortable heating of the vehicle-in insufficient heat emission by the driver tool drive unit (especially battery) nevertheless one to have sufficient heating power available an additional electrical heater for the heat transfer medium be provided. In its simplest form, this can be done tion form similar to a immersion heater.

As already explained, exists for the vehicle battery an optimal operating temperature level. This Ni However, veau can be temporarily raised if foreseeable is that the temperature of the heat transfer circuit at for example for heating the vehicle interior in visible time must be raised or if in the warm Meträgerkreislauf temperature peak values occur. The like peak values result, for example, from a briefly increased heating of the vehicle drive Electric motor. With the increase in operating temperature Levels can thus peak in heat quantity in the battery can be saved and used later Time by lowering to the usual Be operating temperature level can be called up again. These then needed for example for the vehicle heating The amount of heat advantageously loads the electrical Energy balance of the battery is not. With the raising of the Battery operating temperature levels can be prevented that the heat stored in this way otherwise increases a foreseeable later date not for interior heating is available. Furthermore, this can Increase in the operating temperature level even during the battery is powered by the mains when the outside is low temperature can be set. In particular, the intermittent temperature increase of the battery by leg flow of heat transfer to the cooling heat exchanger and / or on the battery heat exchanger. In particular, one will  of the mass flows flowing through the heat exchanger in ge appropriately influenced. For example, it is possible Lich, the air flow through the cooling heat exchanger to Dros to reduce the cooling of the battery Fluid circuit and thus additional heating of the To achieve battery.

The attached schematic shows a preferred exemplary embodiment of the invention. An electric vehicle is a vehicle drive unit consisting, inter alia, of a vehicle battery 1 and a vehicle drive electric motor 2 . For cooling or temperature control of this vehicle drive unit, a heat carrier circuit, designated in its entirety by 3, is provided, which is conveyed by an electric motor-driven pump 4 and leads, inter alia, via a cooling heat exchanger 5 . By means of a bypass valve 6 , the heat transfer circuit 3 can be passed either via the electric motor 2 or via a bypass 7 . Further ele ments of the heat transfer circuit 3 are a compensation tank 8 , an immersion heater-like electrical heater 9 as well as additional elements 10 to be cooled or tempered, such as electrical auxiliary units or an electronic control unit.

The cooling heat exchanger 5 is arranged in an air duct 11 through which an air flow conveyed by a fan 12 flows. In the air duct 11 downstream of the Wärmetau shear 5 , a switching flap 13 is provided, which directs the exhaust air flow of the heat exchanger 5 either into the surroundings arrow ( 14 a) or into the vehicle interior arrows ( 14 b). At least one further switching flap 15 is provided for the individual distribution of the air flow entering the vehicle interior. At the same time via a bypass duct 16 to the air duct 11, an air flow also conveyed by the blower 12 , according to arrow 14 c, can get into the vehicle interior as a non-treated ventilation air flow.

If, for example, the shortest possible heating of the vehicle interior is desired after starting the electric vehicle, then the liquid heat transfer medium in the heat transfer circuit must be heated very quickly. This can be done with the help of the electrical heater 9 or - as already explained - by lowering the battery operating temperature from an elevated level to the usual level with the aid of a battery heat exchanger 18 . However, it is desirable to keep the electric motor 2 cooled by the previous standstill phase of the electric vehicle cool for as long as possible. Here, the bypass valve 6 is now switched so that the already heated heat transfer medium is passed completely through the bypass 7 . The electric motor 2 is thus only integrated into the heat transfer circuit 3 when it requires cooling. The bypass valve 6 can be designed as a simple changeover valve or as a volume flow distribution valve. In the latter case, a particularly individual temperature control is possible, while in the former case the bypass valve 6 can also be operated in a quasi-cycle operation.

If, on the other hand, there is a higher amount of heat on the electric motor 2 than is required to heat the vehicle interior, then - if a further heating requirement is foreseeable - the battery can be operated at a somewhat higher operating temperature level and thus this amount of heat in the vehicle battery 1 can be saved. This vehicle battery 1 is, in particular, a sodium-sulfur battery whose optimum operating temperature level is in the order of magnitude of 320 ° C. In order to keep the battery at this temperature level, a fluid circuit 17 flowing through the battery is provided in addition to an internal electrical battery heater (not shown), which runs via a battery heat exchanger 18 with the heat transfer circuit 3 in heat-transferring connection. It is thus possible to temper the vehicle battery 1 via the heat transfer circuit 3 and the fluid circuit 17 and via the internal electrical heating. If there is an additional amount of heat in the heat carrier circuit for a short time, it can be stored in the battery 1 . For this purpose, the battery 1 can be temporarily heated at least slightly above the usual battery operating temperature. At a later point in time, this amount of heat can be retrieved from the battery 1 and used in particular to heat the vehicle interior. The temporary temperature increase of the battery and of course the reverse process, ie the subsequent temperature reduction, can be done by ge suitable influencing the heat transfer at the cooling heat exchanger 5 and / or on the battery heat exchanger 18 . For example, to increase the temperature of the vehicle battery 1, the temperature level of the heat carrier circuit 3 can be increased by reducing the air flow passing through the cooling heat exchanger 5 . Alternatively, however, it is also possible to change the quantity of the heat carrier circuit 3 flowing through the battery heat exchanger 18 or the fluid circuit 17 . In addition, the battery operating temperature can be raised by means of the internal electric battery heater, especially when a battery is being charged, if sufficient electrical energy is available. Of course, further deviations from the embodiment shown are possible, which fall under the content of the claims.

Claims (5)

1. Heat transfer circuit of an electric vehicle, the liquid heat transfer medium from the vehicle drive unit ( 1 , 2 ) and / or to be cooled to add-on elements ( 10 ) absorbs heat and in a cooling heat exchanger ( 5 ) to one in the vehicle-in nenraum (arrow 14 b) and / or in the environment (arrow 14 a) emitted air flow, characterized in that the heat transfer circuit ( 3 ) via a battery heat exchanger ( 18 ) flowing into a vehicle battery ( 1 ) Fluid circuit ( 17 ) is integrated, and via a vehicle drive electric motor ( 2 ) and / or via a bypass ( 7 ) leads to the electric motor ( 2 ) and / or flows through a heat exchanger for the elements to be cooled ( 10 ). 2. Heat transfer circuit according to claim 1, characterized by a bypass valve ( 6 ) designed as a quantity distribution valve for the bypass ( 7 ). 3. Heat transfer circuit according to claim 1 or 2, characterized by an additional electrical heater ( 9 ) for the heat transfer medium. 4. Operating method for a heat transfer circuit according to one of claims 1 to 3, characterized in that the temperature of the bat terie ( 1 ) is temporarily raised at least slightly above the usual battery operating temperature, to thereby shear when necessary via the battery heat exchanger ( 18 ) to heat the heat transfer medium. 5. Operating method according to claim 4, characterized in that the temporary temperature increase of the battery ( 1 ) by influencing the heat transfer to the cooling heat exchanger ( 5 ) and / or on the battery heat exchanger ( 18 ).