| JP2005093144 | BATTERY-COOLING SYSTEM, AND POWER SUPPLY DEVICE AND MOTOR VEHICLE EQUIPPED WITH THE SYSTEM |
| JP2011238374 | BATTERY PACK |
| JP2008186595 | SECONDARY BATTERY |
KOLASA, Magnus (Skarpbrunnavägen 195, Norsborg, S-145 64, SE)
| Claims 1. A cooling and warming system for a device, which system comprises a cooling unit, a warming unit, a temperature sensor adapted to detecting the temperature of the device and to delivering to a control unit a temperature signal based on temperatures 5 detected, and a pipe system arranged to convey a medium for cooling and warming so that the device is respectively cooled and warmed, c h a r a c t er i s ed in that the system further comprises a reversible pump situated close to the pipe system and adapted to moving the medium in the pipe system in a first direction or in a second direction which is opposite to the first 0 direction, depending on control signals from the control unit, a number of one-way valves situated close to the respective cooling unit and warming unit in such a way that the flow through the one-way valves passes either the cooling unit or the warming unit, depending on the respective pump direction, the control unit being adapted to delivering to the pump, on the basis of the temperature S signal, control signals to pump the medium in a first direction if the device is to be cooled and in a second direction if the device is to be warmed. 2. A system according to claim 1, in which the control unit comprises a comparison unit adapted to comparing the temperature indicated by the temperature signal0 with a settable first temperature level T 1 , and if the temperature signal exceeds the first temperature level a first control signal is delivered to the pump to pump in the direction causing the one-way valve of the cooling unit to let medium through, while the one-way valve of the warming unit prevents medium from passing, with the result that the device is cooled. 5 3. A system according to claim 2, in which the comparison unit is further adapted to comparing the temperature indicated by the temperature signal with a settable second temperature level T2 which is lower than or equal to the first temperature level Tl , and if the temperature is below the settable second temperature level, a second control0 signal is delivered to the pump to pump in the second direction, causing the one-way valve of the warming unit to let medium through, while the one-way valve of the cooling unit prevents medium from passing, with the result that the device is warmed. 4. A system according to claim 3, in which the first temperature level is in the range 30-60°C and the second temperature level is in the range 0-30°C. 5. A system according to any one of the foregoing claims, in which the oneway valves are integrated in the respective cooling and warming units. 6. A system according to claim 3 or 4, in which a third temperature level T3 is inserted between T2 and Tl , such that temperatures lower than T2 are in a range A, the range between T2 and T3 is called range B, the range between T3 and Tl is called range C, and temperatures higher than Tl are in a range D. 7. A system according to claim 6, in which T3 is placed at the optimum working temperature of the device. 8. A system according to claim 6 or 7, in which differentiated warming and cooling are respectively effected in ranges B and C by the pump in range B running slower than in range A, and by the pump in range C running slower than in range D. 9. A system according to any one of the foregoing claims, in which the device is a battery. 10. A hybrid vehicle or electric vehicle which has a cooling and warming system according to any one of the foregoing claims. |
Cooling and warming system Field of the invention
The present invention relates to a cooling and wanning system according to the preamble of the independent claim.
Background to the invention
For batteries in, for example, hybrid vehicles and electric vehicles to achieve optimum performance and service life, they need to be allowed to operate within an optimum temperature range. This usually entails having to provide both cooling and warming for these units. To minimise losses in the cooling and warming system, it is desirable that the cooling medium should only pass through the components which are in operation.
Cooling involves using, for example, a waterborne system with a radiator or an AC evaporator, and wanning involves using, for example, an electric water heater. Altering the route of the cooling medium may be by means of an electrically controlled valve which chooses loops in the cooling system. Using electrically controlled valves entails extra control outputs from a suitable control unit, increasing the cost and complexity of the cooling and warming system, the electrical system and the control unit.
US 5,215,834 refers to a control system for effecting cooling or warming of a battery according to the battery's temperature and charge status. The battery is cooled by air supplied to it by a reversible fan capable of providing air flow in two directions. US 2004/0061480 refers to a battery with a system for cooling and warming the battery according to temperature by using a medium, e.g. air, which a fan causes to pass through and past the battery. Valve devices are used to control the air flow, and the direction of flow may likewise be altered by reversing the fan. WO 2009/046269 refers to a temperature management system for an energy source, e.g. a fuel cell or a battery, comprising inter alia a temperature sensor for detecting the temperature of the energy source, and a pump which pumps a medium past, in order to warm or cool, the energy source. A valve may be set to cause warming or cooling by controlling the flow past the energy source from a cooling unit or a warming unit.
Cooling and warming systems according to the state of the art require in certain cases active control to effect cooling and warming. This entails a more complex system which is more expensive and often more complicated to make.
The object of the present invention is to propose a cooling and warming system which is robust, of less complexity than present-day systems, and simple and therefore inexpensive to make.
Summary of the invention
The above object is achieved by the invention as defined by the independent claims.
Preferred embodiments are defined by the dependent claims.
The invention thus relates to a cooling and warming system for a device, e.g. a battery, which system comprises a cooling unit, a warming unit, a temperature sensor adapted to detecting the temperature of the device and to delivering to a control unit a temperature signal based on temperatures detected, and a pipe system arranged to convey a medium for cooling and warming so that the device is respectively cooled and warmed. The system further comprises a reversible pump situated close to the pipe system and adapted to moving the medium in the pipe system in a first direction or in a second direction which is opposite to the first direction, depending on control signals from the control unit. A number of one-way valves are situated close to the respective cooling unit and warming unit in such a way that the flow through the one-way valves passes either the cooling unit or the warming unit, depending on the respective pump direction. The control unit is adapted to delivering to the pump, on the basis of the temperature signal, control signals to pump the medium in a first direction if the device is to be cooled and in a second direction if the device is to be warmed.
The invention achieves the same functionality as in a system which comprises an electrically controlled three-way valve. Preferably, two one-way valves are provided, one of them close to the cooling unit, the other close to the warming unit. The valves are so arranged that the flow is allowed in opposite directions in the respective cooling and warming circuits. Choice of circuit is then by reversing the direction of flow through the battery, i.e. by reversing the direction of the pump.
According to the present invention there is no need for active control of valves. A complex and expensive component is replaced by two simpler and less expensive components. One or both of the one-way valves may be preferably be integrated in other components, further reducing the complexity of the system. The pressure drop becomes the lowest possible during operation in that no active component hinders the flow.
Brief description of drawings
Figure 1 is a schematic block diagram illustrating the present invention.
Figure 2 is a schematic block diagram illustrating the present invention during cooling of a device.
Figure 3 is a schematic block diagram illustrating the present invention during warming of a device.
Figure 4 is a graph of various temperature ranges to illustrate the present invention.
Detailed description of preferred embodiments of the invention
The invention is described below in detail with reference to the drawings. Figure I is a schematic block diagram of a cooling and wanning system for a device, which system comprises a cooling unit, a warming unit, a temperature sensor adapted to detecting the temperature of the device and to delivering to a control unit a temperature signal on the basis of temperatures detected. The device, the cooling unit and the warming unit are connected together by a pipe system which is arranged to convey to the device a medium for cooling and warming so that the device is respectively cooled and warmed. The pipe system is represented in the drawings by bold lines.
The device to be warmed or cooled is, according to an embodiment, a battery or a number of batteries, situated for example in a hybrid vehicle, e.g. a bus, truck or passenger car. The cooling and warming system according to the present invention may also be used to cool and warm other devices, e.g. DC/DC converters, other power electronics converters, electric motors etc., i.e. the cooling and warming system may be used to cool and warm any device which has a temperature range for optimum function.
The cooling unit may for example take the form of an evaporator or a heat exchanger which is cooled by the draught caused by the vehicle being in motion.
The warming unit may take for example the form of an electric heater, a heat exchanger connected to a vehicle's exhaust system in order to utilise the heat therefrom, or connected to a vehicle's cooling system which is intended to cool the vehicle's engine.
The temperature sensor may for example be a resistive temperature pickup in the form of a component which changes resistance with temperature.
The system further comprises a reversible pump situated close to the pipe system and adapted to moving the medium in the pipe system in a first direction or in a second direction which is opposite to the first direction, depending on control signals from the control unit.
A number of one-way valves are situated close to the respective cooling unit and warming unit in such a way that the flow through the one-way valves passes either the cooling unit or the warming unit depending on the respective pump direction. Preferably, one of the one-way valves is situated close to the cooling unit, and the other close to the warming unit.
The control unit is adapted to delivering to the pump, on the basis of the temperature signal, control signals to pump the medium in a first direction if the device is to be cooled and in a second direction if the device is to be warmed. This is illustrated in Figures 2 and 3, and the arrows in Figure 2 indicate the direction of flow when the device is to be cooled and the medium can pass the cooling unit but is prevented, by the respective one-way valve, from passing the warming unit. Similarly, Figure 3 shows the system adapted to warming the device in that the direction of flow indicated by the arrows is such that the medium can pass the warming unit but is prevented, by the respective one-way valve, from passing the cooling unit.
The control unit comprises a comparison unit (not depicted in the drawings) adapted to comparing the temperature indicated by the temperature signal with a settable first temperature level, and if the temperature signal exceeds the first temperature level a first control signal is delivered to the pump to pump in the direction causing the one-way valve of the cooling unit to let medium through, while the one-way valve of the warming unit prevents medium from passing, with the result that the device is cooled. This is illustrated in Figure 2.
The comparison unit is further adapted to comparing the temperature indicated by the temperature signal with a settable second temperature level which is lower than or equal to the first temperature level, and if the temperature is below the settable second temperature level, a second control signal is delivered to the pump to pump in the second direction, causing the one-way valve of the warming unit to let medium through, while the one-way valve of the cooling unit prevents medium from passing, with the result that the device is warmed. This is illustrated in Figure 3. Figure 4 is a graph illustrating a temperature range between - 10 and 60°C. The first and second temperature levels are marked Tl and T2 respectively. A third temperature level T3 is also marked, as too are four temperature ranges A, B, C and D, A comprising temperatures lower than T2, B the range between T2 and T3, C the range between T3 and Tl , and D temperatures higher than Tl .
An example of an application of the cooling and warming system according to the present invention is described next with reference to Figure 4.
In this example, the device is a battery in a hybrid vehicle, with an optimum working temperature in the range 10-50 degrees.
At temperatures lower than T2, the control unit will cause the pump to pump in the direction indicated in Figure 3, i.e. the direction, causing warming of the battery. If the temperature exceeds Tl, the control unit will instead cause the pump to pump in the direction indicated in Figure 2, i.e. the direction, causing cooling of the battery.
Further temperature levels may be used to further improve the temperature control. For example, a third temperature level T3 may be inserted between T2 and T 1. The object of T3 may be to place it at the most optimum working temperature for the battery and to insert differentiated warming and cooling respectively in ranges B and C. This means that in range B the pump runs slower, resulting in less warming effect than in range A.
Similarly, in range C the pump runs slower, resulting in less cooling effect than in range D.
The temperature levels may also be used to completely disconnect the battery, i.e. to prevent energy offtake, if the temperature is outside an acceptable range. If for example the temperature is below T2, the system will warm the battery, but the battery will not be connected until the temperature exceeds T2. In range B, the warming may continue with full power, with less power or none at all, depending on what is chosen by the operator or is determined by a chosen regulating strategy.
When the temperature exceeds T3, the pump may instead begin to pump in the opposite direction in order to provide cooling. It may do so with full power or with less power. If the temperature exceeds Tl, the battery is disconnected in whole or in part, and only cooling with full power takes place until the temperature is again in range C.
According to an embodiment, the first temperature level Tl is in the range 30-60°C, e.g. 50°C, as illustrated in Figure 4, and the second temperature level T2 is in the range 0- 30°C, e.g. 10°C, as also illustrated in Figure 4.
The third temperature level T3 in the example in Figure 4 is placed at about 25°C. The one-way valves used are preferably simple mechanical valves, comprising for example a ball which rests in a seat, is held therein by a spring, allows liquid to move in one direction, against the force of the spring, and prevents liquid movement in the other Ί
direction. Another alternative is a simple spring-loaded pivotable damper which can be pivoted in a direction against the spring force and which seals in the other direction.
The one-way valves may be separate units or be integrated in the respective cooling and warming units.
The present invention also comprises a hybrid vehicle or an electric vehicle which is provided with a cooling and warming system as described above. The present invention is not confined to the preferred embodiments described above.
Sundry alternatives, modifications and equivalents may be used. The above embodiments are therefore not to be regarded as limiting the invention's protective scope which is defined by the attached claims.