A capacitor module

Abstract

The invention relates to a capacitor module (10) for a vehicle, wherein the module comprises a capacitor (12) comprising a plurality of capacitor units operatively connected to each other, a first port (14) for connection to a power supply device (4), a second port (16) for connection to an electric machine (8) for starting an internal combustion engine, and a third port (18) for grounding. The capacitor module (10) comprises a first electronic device (22) connected between the first port (14) and the capacitor (12), and the first electronic device is adapted to allow a current flow from the capacitor module via the first port (14) for supplying at least one load in case of a sudden voltage drop in the power supply from the power supply device (4) during operation.

Description

Technical Field

[0001] The present invention relates to a capacitor module for a vehicle, and more specifically, to a system in which the capacitor module is arranged for connection to an electric motor for starting an internal combustion engine. Background Technology

[0002] Vehicles with internal combustion engines have a starter. The starter includes an electric motor adapted to rotate the crankshaft of the internal combustion engine to start it. The electrical energy required to drive the motor is obtained from an energy storage device, which may be a battery.

[0003] The starting power or energy required to start an internal combustion engine depends on the engine's temperature. At low temperatures, due to higher static friction and greater oil viscosity, the required starting energy is greater than that required at higher temperatures. Furthermore, the maximum available discharge current is reduced, especially in partially charged or aged batteries. Therefore, the starting reliability of conventional vehicles decreases at low temperatures.

[0004] To increase starting reliability, it is known to use an energy storage device in the form of a capacitor, operably connected to the motor. The capacitor is charged before starting the internal combustion engine. The capacitor has a lower internal resistance than a battery, and therefore can provide a large discharge current during starting operation almost independently of temperature. Furthermore, the capacitor has the advantage of being able to be recharged quickly.

[0005] Furthermore, the vehicle has multiple loads in the form of auxiliary devices (which can be engine electrical systems and lighting devices such as lights, audio systems, heaters, air conditioning, etc.). These auxiliary devices can also be powered by electrical energy storage devices. In addition, electrical systems including capacitors and batteries for supplying power to the consumable devices are also known. During operation, there may be conflicting power demands from the consumable devices, and transient situations may occur, which under certain operating conditions may lead to insufficient power to some consumable devices. Summary of the Invention

[0006] One object of the present invention is to provide a capacitor module that enables improved performance of electrical systems in vehicles.

[0007] This objective is achieved by a capacitor module for a vehicle. The module includes: a capacitor comprising a plurality of capacitor cells operatively connected to each other; a first port for connection to a power supply device; a second port for connection to a motor for starting an internal combustion engine; and a third port for grounding. The capacitor module is characterized in that it includes a first electronic device connected between the first port and the capacitor, and the first electronic device is adapted to allow current to flow out of the capacitor module via the first port for supplying power to at least one load during operation in the event of a sudden voltage drop in the power supply from the power supply device.

[0008] The capacitor may be referred to as a supercapacitor or a supercapacitor.

[0009] Therefore, if a current transient occurs in the electrical system, resulting in a sudden voltage drop, the capacitor is arranged to provide a relatively high current and maintain voltage stability. This helps avoid certain undesirable consequences for the driver, such as jolts and operational interruptions. More specifically, the capacitor module is adapted to provide high power to the first port for a short duration.

[0010] More specifically, the capacitor module enables reliable operation of the motor (starter motor) at any speed without the risk of negatively impacting the system voltage. Furthermore, the capacitor module allows for simultaneous current support of the system in the event of a sudden voltage drop.

[0011] In modern vehicles, there are load / consumption devices, such as power steering and / or brake boosters, that may require a significant amount of power under certain operating conditions, potentially exceeding the power supplied by the electrical equipment. This necessitates providing this additional power. A 12V battery can be installed to provide power under such operating conditions; however, there may be situations where the battery cannot provide the required power, such as if it is low in charge or malfunctions for other reasons.

[0012] The capacitor module described above, specifically designed for operation of a motor (starter motor) via the second port, is also adapted to allow current to flow out of the capacitor module via the first port for supplying power to the at least one load during operation in the event of a sudden voltage drop in the power supply from the power source. Therefore, the capacitor module is adapted to automatically supply power to the load (auxiliary device) in the event of a sudden voltage drop (transient) in the power supply from the voltage source (DC / DC) to the load.

[0013] According to one example, a first port is operatively connected to a capacitor, a second port is operatively connected to a capacitor, and a third port is operatively connected to a capacitor.

[0014] According to one embodiment, the first electronic device is arranged to provide low resistance relative to the current in one direction and high resistance in another direction. More specifically, the first electronic device is ideally arranged to provide infinite resistance relative to the current in the other direction. The first electronic device may be arranged such that it provides low resistance relative to the current in the direction toward the first port.

[0015] According to another embodiment, the first electronic device forms a switch, which is adapted to be automatically controlled according to parameters indicating voltage or current.

[0016] According to a further improvement of the last mentioned embodiment, the first electronic device is adapted to perform automatic control based on the relationship between the system voltage and the voltage on the supercapacitor.

[0017] According to a further improvement of the last mentioned embodiment, the first electronic device is adapted to automatically turn on when the system voltage is lower than the voltage on the supercapacitor, and automatically turn off when the voltage on the supercapacitor is lower than the system voltage.

[0018] According to an alternative further improved above, the first electronic device is adapted to automatically disconnect if the surge current to the capacitor exceeds a predetermined threshold, but allows any discharge current from the capacitor to the electrical system.

[0019] According to a further improvement of the last mentioned embodiment, the first electronic device includes a diode. Due to the structure and function of the diode, it forms a suitable electrical component for providing low (ideally zero) resistance relative to current in one direction and high (ideally infinite) resistance in another direction. A diode can be defined as a two-terminal electronic component that conducts primarily in one direction (asymmetric conductance).

[0020] According to a further improvement of the last mentioned embodiment, the first electronic device includes a metal-oxide-semiconductor field-effect transistor (MOSFET). Due to the structure and function of the MOSFET, it forms a suitable electronic component for providing low (ideally zero) resistance relative to current in one direction and high (infinite) resistance in the other direction.

[0021] According to another embodiment, the capacitor module includes a second electronic device connected between the first port and the capacitor, wherein the second electronic device is adapted to open and close the electrical connection between the first port and the capacitor in response to a control signal. More specifically, the second electronic device forms a switch.

[0022] According to a further improvement of the last mentioned embodiment, the second electronic device is connected between the first electronic device and the capacitor.

[0023] According to a further improvement of the last mentioned embodiment, the second electronic device includes two metal-oxide-semiconductor field-effect transistors (MOSFETs) arranged back-to-back. Due to the structure and function of the two MOSFETs arranged back-to-back, such an arrangement forms suitable electrical components for providing switching functions.

[0024] According to another embodiment, the capacitor module includes a third electronic device connected between the first port and the capacitor, and the third electronic device is adapted to limit the current flowing into the first port to a predetermined level.

[0025] According to another aspect of the invention, a further object is to provide an electrical system for a vehicle that creates conditions for improved performance.

[0026] The aforementioned objective is achieved by an electrical system for a vehicle. The system includes: a power supply device; at least one load operably connected to the power supply device; an electric motor adapted to start an internal combustion engine; and a capacitor module according to any of the foregoing embodiments, wherein the capacitor module is operably connected to the power supply device via a first port for supplying power to the at least one load during operation in the event of a sudden voltage drop in the power supply from the power supply device, and wherein the capacitor module is operably connected to the electric motor via a second port.

[0027] According to one embodiment, the system includes a low-voltage energy storage device operably connected to the at least one load to supply power to the at least one load. The low-voltage energy storage device may be formed of a battery, such as a 12V lead-acid battery. The capacitor module may be arranged to provide redundancy to the 12V battery.

[0028] According to another aspect of the invention, the present invention relates to a vehicle comprising the electrical system described above.

[0029] According to another aspect of the invention, a further object is to provide a method for operating an electrical system for a vehicle, which creates conditions for improved performance.

[0030] This objective is achieved through the following steps: maintaining the connection between the capacitor and the first port during operation, thereby allowing current to flow out of the capacitor module via the first port, and supplying power to the at least one load in the event of a sudden voltage drop in the power supply from the power supply device during operation.

[0031] According to one embodiment, the method includes the step of establishing a connection between a capacitor and a first port when the vehicle is started. For example, the control unit may be adapted to close a switch in the capacitor module when the vehicle is started, thereby establishing the connection, wherein the capacitor can be charged at the same voltage level as the board net.

[0032] Further advantages and advantageous features of the invention will be disclosed in the following description and in the dependent claims. Attached Figure Description

[0033] Referring to the accompanying drawings, embodiments of the present invention, which are cited as examples, will now be described in more detail. In the attached diagram: Figure 1 is a schematic diagram of an electrical system according to an exemplary embodiment of the present invention. Figure 2 is a schematic diagram of a capacitor module according to an exemplary embodiment of the present invention, which forms part of the electrical system shown in Figure 1, and Figure 3 is a schematic diagram of a vehicle including the electrical system shown in Figure 1 according to an exemplary embodiment of the present invention. Detailed Implementation

[0034] Figure 1 is a schematic diagram of an electrical system 2 including a power supply device 4 in the form of a DC / DC converter.

[0035] The electrical system 2 also includes at least one load 6 operably connected to the power supply equipment 4. The load may be formed by auxiliary devices, such as circuitry for engine control, braking, and steering. Furthermore, the load may be formed by lighting fixtures such as lamps, audio systems, heaters, air conditioners, compressors, etc.

[0036] Electrical system 2 also includes an electric motor 8 suitable for starting the internal combustion engine 102, see Figure 3. The electric motor 8 may be formed from a starter motor having gears that mesh with an engine starter gear (ring gear) that is rotatably and rigidly connected to the crankshaft of the engine. See also... Figure 2 The motor 8 is powered by the capacitor 12, which will be described below, and forms a starter motor for driving or rotating the crankshaft when the engine is started. According to an alternative, the starter and the generator connected to the engine crankshaft are formed by the same unit, becoming a single integrated starter-generator.

[0037] Electrical system 2 also includes capacitor module 10, which is shown in more detail in Figure 2. Capacitor module 10 includes capacitor 12, which includes a plurality of capacitor cells operatively connected to each other.

[0038] Capacitor 12 is an electrical energy storage device installed as a dedicated power supply for a starter motor. Capacitor 12 can be formed from an electric double-layer capacitor (eDLC), which has large capacitance and excellent characteristics in terms of rapid charging and discharging performance. For example, this capacitor can be formed by connecting six double-layer capacitors with a rated voltage of 2.5V. According to an alternative scheme, the number of capacitor cells can be less than or greater than six, and the rated voltage of each cell can be different from 2.5V. Therefore, the capacitor can be charged to 15V (= 2.5V). 6). Capacitor 12 can be formed by connecting multiple units in series and / or parallel.

[0039] The capacitor module 10 also includes a first port 14 for connection to the power supply device 4, a second port 16 for connection to the motor 8 for starting the internal combustion engine, and a third port 18 for connection to the ground 20. The ground 20 may be formed from the underside of the chassis in the vehicle.

[0040] Furthermore, the capacitor module 10 includes a first electronic device 22 connected between the first port 14 and the capacitor 12. The first electronic device 22 is adapted to allow current to flow out of the capacitor module 10 via the first port 14 for supplying power to at least one load 6 during operation in the event of a sudden voltage drop in the power supply of the self-powered device 4. The first electronic device 22 is arranged to provide low (ideally zero) resistance relative to the current in one direction and high (ideally infinite) resistance in another direction. According to one example, the first electronic device includes a diode. According to one example, the first electronic device includes a metal-oxide-semiconductor field-effect transistor (MOSFET). Therefore, in other words, the first electronic device forms a power MOSFET.

[0041] More specifically, the first electronic device 22 forms a switch adapted for automatic control based on the relationship between the system voltage and the voltage across the supercapacitor 12. More specifically, the first electronic device 22 automatically turns on when the system voltage (via port 14) is lower than the voltage across the supercapacitor 12. Furthermore, the first electronic device 22 automatically turns off when the voltage across the supercapacitor 12 is lower than the system voltage.

[0042] The automatic disconnection feature can also be triggered by current measurement, rather than by measuring and comparing the voltage across the electrical system and supercapacitor 12. For example, if the surge current exceeds a predetermined threshold, the connection between supercapacitor 12 and the electrical system is disconnected, but any discharge current from supercapacitor 12 to the electrical system is allowed. This can be achieved by using a commonly used shunt and voltage comparator together.

[0043] The capacitor module 10 is operatively connected to the power supply device 4 via a first port 14 to provide power to at least one load 6 in the event of a sudden voltage drop in the power supply from the power supply device 4 during operation, and wherein the capacitor module is operatively connected to the motor 8 via a second port 16.

[0044] Furthermore, the capacitor module 10 includes a second electronic device 24 connected between the first input 14 and the capacitor 12. The second electronic device 24 is adapted to turn the electrical connection between the first input 14 and the capacitor 12 on and off in response to a control signal. Therefore, the second electronic device 24 forms a switch. As shown by dashed line 34, the switch 24 is controlled via a control signal from the control unit 32. The second electronic device 24 is connected between the first electronic device 22 and the capacitor 12. According to one example, the second electronic device 24 includes two metal-oxide-semiconductor field-effect transistors (MOSFETs) arranged back-to-back.

[0045] Furthermore, the control unit 32 is also adapted to perform analog voltage measurements directly on the capacitor 12 for diagnostic purposes, as shown by dashed line 36. A ground connection is established through the ground connection of the control unit 32.

[0046] Furthermore, capacitor module 10 includes a third electronic device 26 connected between first input 14 and capacitor 12, the third electronic device 26 being adapted to limit the current flowing into the first port to a predetermined level. In other words, the third electronic device 26 forms a charging current limiting circuit. For example, the third electronic device 26 may include a DC / DC buck converter (not shown) for limiting the current flowing into the first port to a predetermined level. First electronic device 22 is arranged in parallel with charging current limiting circuit 26. Alternatively, first electronic device 22 may form part of charging current limiting circuit 26.

[0047] In addition, capacitor module 10 includes a cell balancing unit 46 operatively connected to capacitor 12. This cell balancing unit 46 is adapted to ensure that the capacitor cells maintain the same voltage level to prevent premature aging of individual capacitor cells.

[0048] Electrical system 2 also includes a low-voltage energy storage device 28 in the form of a battery, operably connected to at least one load 6 to provide power to the at least one load. Battery 28 may be a rechargeable 12V battery, arranged to power auxiliary equipment other than the starter motor 8. For example, a lead-acid battery may be used. In other words, according to... Figure 1 The power supply system shown uses a 12V battery to power the 12V system load, while a capacitor powers the starter. The capacitor module 10 and the 12V battery 28 are connected to a DC / DC converter 4 via a DC branch harness 30. The DC / DC converter 4 is adapted to convert several hundred volts from a high-voltage circuit to 12V.

[0049] Electrical system 2 also includes a starter relay 38, which is connected to the starter motor solenoid 40. Referring to dashed line 44, engine control unit 42 is adapted to control the starter relay.

[0050] The DC / DC converter 4 performs two main functions: converting 400 V DC power from the associated high-voltage system 48 to 12 V DC power, and converting the AC voltage generated by the motor (not shown) from the high-voltage system 48 to 400 V DC power. When the vehicle is in electric mode, a 400 V high-voltage energy storage device, such as a lithium-ion battery pack (not shown), supplies power to the DC / DC converter 4 to supply the 12 V load and simultaneously to the motor that drives the vehicle forward. When the engine is started, the motor generates power to both the 400 V battery and the DC / DC converter 4.

[0051] Now let's turn to an example of how electrical system 2 operates.

[0052] When switch 24 is closed during operation, current can flow through first port 14 in either direction. The current flowing into first port 14 will be limited to 50A by DC / DC buck converter 26. The current flowing out of first port 14 is not actively limited and will help stabilize the board net voltage.

[0053] If a current transient occurs (e.g., from the power steering system and / or brake booster), and the DC / DC converter 4 (or the alternator in a conventional vehicle) cannot maintain a stable voltage, the capacitor 12 is capable of acting as redundancy for the 12 V lead-acid battery 28, providing the grid with more than 300A and maintaining a stable voltage.

[0054] When the vehicle is started, the control unit 32 closes the switch 24, and the capacitor 12 charges at the same voltage level as the grid. Charging automatically stops when the predetermined voltage level has been reached.

[0055] If the voltage on capacitor 12 exceeds a specific threshold, 12V starting is permitted. During 12V starting, engine control unit 42 shuts off starter relay 38, which in turn shuts off starter motor solenoid 40. The current supplied to starter motor 8 is provided solely by capacitor 12 through second port 16, thus eliminating the possibility of grid voltage instability. When the voltage on capacitor 12 drops, charging operation automatically begins, drawing a maximum of 50A from the grid.

[0056] If a fault occurs that causes capacitor 12 to draw more than 50A from the grid, an internal fuse (not shown) will prevent any further use of capacitor 12 and starter motor 8 until they are replaced at the factory.

[0057] Switch 24 will remain closed when the vehicle is in driving mode or if an external charger (not shown) is connected to the vehicle. When the vehicle is stationary (and no charger is connected), the switch will be open.

[0058] Each of the control units 32 and 42 may include one or more microprocessors and / or one or more memory devices or any other components for executing computer programs to control the electrical system and perform the methods of the present invention. Therefore, the control unit is preferably provided with a computer program for operating the system and performing the steps of the methods described above. Furthermore, the control unit may be part of a controller that can also be used for other functions of the electrical system and / or any other functions of the vehicle, or may be provided as a separate unit.

[0059] Figure 3 This is a schematic diagram of a vehicle 100 according to an exemplary embodiment of the present invention, wherein the vehicle 100 includes Figure 1 The electrical system 2 shown is included in the vehicle. The vehicle includes an internal combustion engine 102. An electric motor 8 is adapted to start the internal combustion engine 102. Furthermore, the crankshaft of the engine 102 is drivably connected to the transmission 104, and the output shaft of the transmission is drivably connected to the left and right wheels via a differential gear 106.

[0060] It should be understood that the present invention is not limited to the embodiments shown above and in the accompanying drawings, and those skilled in the art will recognize that many changes and modifications can be made within the scope of the appended claims.

[0061] Therefore, the above system relates to vehicles with internal combustion engines. The internal combustion engine can be adapted to provide prime mover power for traction via a mechanical transmission system. This system can also be applied to hybrid vehicles, which are vehicles with two or more power sources such as internal combustion engines and electric sources. Furthermore, the internal combustion engine can be dedicated to charging the electric source.

[0062] The vehicle described above is a passenger car, but it can also be a truck, bus, surface vessel, ship, or aircraft.

Claims

1. A capacitor module (10) for a vehicle, wherein, The module includes: - Capacitor (12), said capacitor (12) comprising a plurality of capacitor cells operatively connected to each other; - First port (14) for connecting to power supply equipment (4); - A second port (16) for connecting to the motor (8) used to start the internal combustion engine; and - Third port (18) for grounding The capacitor module (10) includes a first electronic device (22) connected between the first port (14) and the capacitor (12). The first electronic device is adapted to allow current to flow out of the capacitor module via the first port (14) to supply power to at least one load during operation in the event of a sudden voltage drop in the power supply from the power supply device (4). The first electronic device (22) is arranged to provide low resistance relative to the current in one direction and high resistance in the other direction. The capacitor module (10) includes a second electronic device (24) connected in series with the first electronic device (22) between the first port (14) and the capacitor (12), and wherein the second electronic device is adapted to open and close the electrical connection between the first port (14) and the capacitor (12) in response to a control signal. The capacitor module (10) further includes a third electronic device (26) connected between the first port (14) and the capacitor and in parallel with the first electronic device (22), wherein the third electronic device is adapted to limit the current flowing into the first port to a predetermined level, and The third electronic device (26) includes a DC / DC buck converter.

2. The capacitor module for a vehicle according to claim 1, wherein, The first electronic device (22) forms a switch, which is adapted to be automatically controlled based on parameters indicating voltage or current.

3. The capacitor module for a vehicle according to claim 2, wherein, The first electronic device (22) is adapted to be automatically controlled based on the relationship between the system voltage and the voltage on the supercapacitor (12).

4. The capacitor module for a vehicle according to claim 3, wherein, The first electronic device (22) is adapted to automatically turn on when the system voltage is lower than the voltage on the supercapacitor (12) and automatically turn off when the voltage on the supercapacitor (12) is lower than the system voltage.

5. The capacitor module for a vehicle according to claim 2, wherein, The first electronic device (22) is adapted to automatically disconnect if the surge current flowing to the capacitor (12) exceeds a predetermined threshold, but allows any discharge current from the capacitor to flow to the electrical system.

6. The capacitor module for a vehicle according to any one of the preceding claims, wherein, The first electronic device (22) includes a diode.

7. The capacitor module for a vehicle according to any one of the preceding claims, wherein, The first electronic device (22) includes a metal-oxide-semiconductor field-effect transistor.

8. The capacitor module for a vehicle according to claim 1, wherein, The second electronic device (24) is connected between the first electronic device (22) and the capacitor (12).

9. The capacitor module for a vehicle according to claim 7 or 8, wherein, The second electronic device (24) includes two metal-oxide-semiconductor field-effect transistors arranged back-to-back.

10. An electrical system (2) for a vehicle, wherein, The system includes: -Power supply equipment (4); - At least one load (6) that can be operatively connected to the power supply equipment. - An electric motor (8) suitable for starting an internal combustion engine; and - A capacitor module (10) according to any one of the preceding claims, wherein the capacitor module is operatively connected to the power supply device (4) via the first port (14) for supplying power to the at least one load (6) in the event of a sudden voltage drop in the power supply from the power supply device (4) during operation, and wherein the capacitor module is operatively connected to the motor via the second port.

11. The electrical system according to claim 10, wherein, The system includes a low-voltage energy storage device (28) operably connected to the at least one load for supplying power to the at least one load.

12. The electrical system of claim 11 further includes a high-voltage system (48), wherein the power supply device (4) is a high-voltage DC / DC converter (4), wherein the high-voltage DC / DC converter (4) is adapted to convert high voltage from the high-voltage system (48) into low voltage of the low-voltage energy storage device (28).

13. The electrical system according to claim 12, wherein, The high-voltage system (48) includes a high-voltage energy storage device configured to provide power to the high-voltage DC / DC converter (4) for supplying power to the at least one low-voltage load (6) and simultaneously supply power to the motor (8) to drive the vehicle forward.

14. A vehicle comprising an electrical system according to any one of claims 10-13.

15. A method for operating an electrical system according to any one of claims 10-13, wherein, The method includes the following steps: During operation, the connection between the capacitor (12) and the first port (14) is maintained, so that current can flow out of the capacitor module via the first port, and in the event of a sudden voltage drop in the power supply from the power supply device during operation, the current can supply power to the at least one load (6).

16. The method according to claim 15, wherein, The method includes the step of establishing a connection between the capacitor (12) and the first port (14) when the vehicle is started.

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