Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
  • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
  • H02J7/04—Regulation of charging current or voltage
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
  • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
  • H02J7/0014—Circuits for equalisation of charge between batteries
  • H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
  • H02J7/0042—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries characterised by the mechanical construction

Definitions

• the invention relates to a charge balancing device being connectable to a battery.
• BMS battery management systems
• cell balancing or charge balancing systems are customarily applied.
• These systems consist of a central unit responsible for control, and subunits being connectable to the individual batteries.
• the central control unit is connected to the subunits via wireless connection.
• Such solutions are disclosed in US 2006/0152190 A1 , US 2008/0071483 A1 , US 2010/0196748 A1 , US 2012/0112685 A1 , US 2013/0017421 A1 , US 2013/0271072 A1 and WO 2013/139921 A2.
• the primary object of the invention is to provide a charge balancing device which is free of the disadvantages of prior art solutions to the greatest possible extent.
• a further object of the invention is to provide a charge balancing device which is adapted for managing heat generated by the transistors on the subunits of the system more effectively compared to known solutions.
• the objects according to the invention can be achieved by the device according to claim 1 .
• Preferred embodiments of the invention are defined in the dependent claims.
• Fig. 1 is a schematic side view illustrating the charge balancing device according to an embodiment of the invention
• Fig. 2 is a schematic top view illustrating the charge balancing device shown in Fig. 1 ,
• Fig. 3A is a schematic drawing illustrating series-connected batteries fitted with the charge balancing device according to the invention
• Fig. 3B is a schematic drawing illustrating a charge control module belonging to the arrangement shown in Fig. 3A,
• Fig. 4 is a schematic circuit diagram illustrating the charge balancing device according to the invention.
• Fig. 5 is a circuit diagram illustrating a detail of a further embodiment of the charge balancing device according to the invention.
• the invention relates to a charge balancing device for a battery.
• An embodiment of the device according to the invention is illustrated in Fig. 1.
• the charge balancing device according to the invention comprises a charge balancing structural element 10 being connectable to a negative terminal 1 1 a and to a positive terminal 11 b of a battery 24 and carrying a charge balancing circuit, and further comprises a transistor 14 forming a part of the charge balancing circuit and having a casing.
• the casing of the transistor is taken to comprise all parts of the transistor except the pins, for example particularly a mounting/carrier plate connected to an optionally comprised plastic cover.
• the charge balancing device further comprises a heat transfer element 12 being galvanically connectable to any of the terminals, in the present embodiment, to terminal 1 1 b, being galvanically connected to the charge balancing structural element 10 at the side thereof facing the battery 24, being electrically conductive, and being adapted for conducting off heat.
• the casing of the transistor 14 is arranged on the side of the charge balancing structural element 10 being opposite the heat transfer element 12, at least partly in the region defined by the heat transfer element 12, and is arranged to be in heat transfer connection with the heat transfer element, such that the heat transfer element 12 is able to efficiently carry off heat generated by the transistor 14.
• the region defined by the heat transfer element 12 is meant to refer to the region assignable on the charge balancing structural element where the heat transfer element 12 is either in contact with the charge balancing structural element 10 or is positioned close to it.
• the heat transfer element is configured as a rectangular plate comprising holes adapted to receive the terminals of the battery.
• the heat transfer element may be ring-shaped, in which case the terminals of the battery can be connected inside the ring.
• an appropriate heat transfer connection is ensured between the casing of the transistor and the heat transfer element, i.e. that heat is adequately transferred from the transistor casing to the heat transfer element, it is conceivable that another object (by way of example, a washer or a metal plate) is arranged between the casing of the transistor and the heat transfer element in addition to the charge balancing structural element.
• the charge balancing structural element is implemented as a printed circuit board, and the transistor is arranged on the reverse side of the printed circuit board opposite the heat transfer element.
• the charge balancing structural element can also be implemented as a cable.
• the transistor is disposed at the cable end proximate to the heat transfer element 12.
• the heat transfer element 12 is in contact with the charge balancing structural element 10, configured as a printed circuit board, through the conductive layer thereof, heat can be conducted off efficiently in the device according to the invention.
• the conductive layer of the charge balancing structural element 10 and the heat transfer element 12 are in contact over a sufficiently large surface area.
• the conductive layer of the charge balancing structural element 10 is constituted by the wiring of the printed circuit board.
• current flows in the conductive layer.
• the current of the charge balancing device also flows through the heat transfer element 12, hence it is required that the heat transfer element 12 is electrically conductive. This current is limited typically to a value about 10 A (ampere).
• an additional conductive layer is arranged on the side of the charge balancing structural element 0 (implemented as a printed circuit) which is opposite the heat transfer element 12. Applying the additional conductive layer a measurement path independent from the above high current (even as high as 10 A) can be established, which measurement path may for example be utilised for control measurement.
• the application of the heat transfer element 12 in a manner according to the invention is also particularly advantageous because thereby the heat generated during operation of the transistor 14 arranged on the charge balancing structural element 10 can be transferred to the heat transfer element 12.
• the heat transfer element 12 has high heat conductivity, and thus heat transferred to the heat transfer element 12 is carried off into the battery 24, that is, the battery 24 behaves as a heat absorber with high thermal inertia. With the application of the device according to the invention, therefore, no additional measures have to be taken in order to conduct off heat generated during operation of the charge balancing device; applying the heat transfer element 12 heat generation does not affect the operation of the battery.
• the heat transfer element 12 is preferably made from copper.
• the heat transfer element 12 is arranged between the charge balancing structural element 10 and the battery 24, and the width of the heat transfer element 12 between the charge balancing structural element 10 and the battery 24 is in the range of 3-30 mm to provide for the appropriate rigidity of the heat transfer element 12.
• the above mentioned width of the heat transfer element 12 is preferably in the range of 5-10 mm such that it may be preferably arranged on the terminals 11 a, 1 1 b of the battery 24 without overhanging to a too large extent with respect to the terminals 1 1a, 1 1 b of the battery 24.
• a plate having a width of 7-9 mm is applied as heat transfer element in case of the most widely applied battery dimensions, the thickness of the heat transfer element is, by way of example, 8 mm.
• the battery 24 is not part of the invention, the device according to the invention is illustrated in Fig. 1 and Fig. 2 connected to the battery 24. In Fig. 1 the battery 24 is shown schematically, with only the portions around the terminals 1 1 a, 1 1b being indicated in the drawing.
• a respective heat transfer element 12 is comprised in the charge balancing device for both terminals 1 1 a, 1 1b of the battery 24.
• the transistor 14 is arranged on the charge balancing structural element 10 at the terminal 1 1 b, i.e. in the right of the drawing.
• pins 15 of the transistor 14 are also shown. Due to the arrangement of the transistor 14 shown in the drawing, a significant amount of heat is generated by the operation of the transistor 14 at this terminal 11 b during operation of the charge balancing device. In the region of the heat transfer element 12 shown in the left of the drawing, however, i.e. at the terminal 11a, no significant heat is generated.
• the arrangement according to Fig. 1 i.e. arranging a respective heat transfer element 12 at both sides, is advantageous from the aspect of the optimisation of the manufacturing process.
• the charge balancing structural element 10 implemented as a printed circuit board, is expediently arranged parallel with the top edge of the battery 24, some kind of spacer element should be applied in any case to the terminal not located near the transistor 14. Accordingly, the charge balancing structural element 10 has to be raised by including some element, i.e. a spacer of some kind has to be applied at both of the terminals. It is not preferred to arrange a heat transfer plate as a spacer only at one of the terminals.
• the charge balancing structural element 10 is secured to the battery 24 applying a respective screw 16, 8 at each of the terminals.
• the screw 18 is included between the heat transfer element 12 and the battery 24.
• the charge balancing structural element 10 is attached to the heat transfer element 12 by screws 20 on both the left and right sides of the drawing.
• a circuit board 22 is also attached to the charge balancing structural element 0.
• Fig. 2 the embodiment of Fig. 1 is illustrated in top plan view. It is also illustrated in this figure that in an embodiment of the invention at least two transistors 14 being connected in parallel are applied, but three, four, or even more transistors may also be arranged. In the embodiment according to Fig. 2 two transistors 14 are arranged on the charge balancing structural element 10. The application of two or more transistors is advantageous because thereby more independent heat paths and independent current paths are established on the charge balancing structural element 10, which may have a positive effect on the service life of the device according to the invention. Furthermore, in the present embodiment the casings of the transistors 14 are arranged at the middle of the region defined by the heat transfer element 12.
• the transistors Since the components of the transistors that are subjected to heating are the casings, from the aspect of providing appropriate heat transfer the arrangement of the casing is important. It is expedient to arrange the transistors in such a way that their casings tend to heat are situated to the greatest possible extent in the region defined by the heat transfer element 12. Therefore, the transistors are preferably arranged near or at the middle of this region. In the embodiment shown in Fig. 1 and Fig. 2 field effect transistors 14 (FETs) are applied. For conducting off the heat generated by the transistor 14 it is expedient to arrange the transistor 14 in a manner shown in the drawing, i.e.
• n-type field-effect transistors are applied, with the transistor 14 being arranged at the positive terminal 1 1 b.
• p- type field-effect transistors are applied, arranged at the negative terminal 1 1a. It is more expedient to apply n-type transistors because most commercially available field-effect transistors are of the n-type.
• the screw joints of the n-type transistors are situated on the drain side of the transistors; and, as it is illustrated in Fig. 5, the drain electrode has to be connected to the positive terminal.
• a first temperature sensor 25b is disposed at the positive terminal 1 1b, and a second temperature sensor 25 is disposed at the negative terminal 1 1 a.
• the temperature sensors 25a and 25b are independent of each other.
• the positive terminal 1 1 b is heated up and the temperature sensor 25b is arranged at the terminal 1 1 b to provide means for limiting this heating if it becomes necessary.
• the heating of the transistor 14 occurs at terminal 1 1b, compared to this terminal the other terminal 1 a heats up only very slowly.
• the values measured by the temperature sensor 25a well represent the internal temperature of the battery 24.
• FIG. 3A a system of charge balancing devices 26 according to an embodiment of the invention comprising radio frequency modules 28 (in short: radio modules), and batteries 32 connected thereto is illustrated.
• radio frequency modules 28 in short: radio modules
• a battery 32 and a charge balancing device 26 may be added, and therefore the charge balancing device according to the invention can be applied for battery systems.
• Fig. 3B shows a central charge controller 34 comprising radio frequency modules 36.
• the charge balancing device 26 is controlled by a central charge controller 34 via a radio frequency module 28. Charge control of the batteries 32 shown in Fig. 3A, i.e.
• the temperature of the individual charge balancing devices 26 can be monitored applying a temperature sensor 30.
• the central charge controller 34 may issue other control signals, and may communicate with a display or monitoring system.
• radio frequency communication can operate at a frequency of 2.4 GHz with a transfer speed of 2 MBps.
• Appropriate scheduling is performed by the central charge controller 34.
• the duration of each polling cycle is approximately 100 ps, and a measurement should be performed for all of the battery cells in every second. Thereby, as many as 1000 series-connected cells can be managed at the same time. In case the battery is not operating, it is sufficient to carry out only one measurement every day.
• Fig. 4 the configuration of the charge balancing device 26 is illustrated by a block diagram.
• the charge balancing device 26 comprising a charge balancing structural element 27, on which, in addition to the radio frequency module 28, a microcontroller 40 and a measurement unit 42 are preferably arranged.
• the measurement unit 42 is a high-precision voltage-, current-, and temperature measurement unit.
• the charge balancing structural element 27 is controlled, by way of example, by a 32-bit microcontroller 40 which provides for transferring information arriving from the measurement unit 42 towards the central charge controller 34 via wireless communication. Additionally, the balancing current is also controlled by the microcontroller 40. In case more than one charge balancing device is applied, communication between the microcontrollers of the charge balancing devices may be implemented applying wireless data transfer which allows for the complete elimination of wiring.
• a big advantage of the charge control device according to the invention is that it can be fully integrated with the battery, and it may be even applied for monitoring a battery while it is out of operation.
• a transistor 38 which, similarly to other embodiments, is implemented as a field-effect transistor, is connected to the charge balancing structural element 27.
• Fig. 4 also shows the temperature sensor 30 and the battery 32.
• Fig. 5 is a circuit diagram illustrating the connections of transistors 44 and 46.
• a respective shunt resistor 48, 50 is connected to the source electrode of each transistor 44, 46.
• the source electrode of each field-effect transistor is connected to the ground through a fuse and a 22 mOhm shunt resistor.
• the control measurement signal is carried from the so-called hot points of the shunt resistors through a respective resistor.
• This resistor has much higher resistance than the shunt resistor, and thus essentially the entire current of the source flows through the shunt resistor.
• the inputs of the field-effect transistors are controlled from a PWM (pulse width modulator) driver.
• PWM pulse width modulator
• the drain electrode of each field-effect transistor is connected to the positive terminal of the battery.
• a current of 5A per field-effect transistor is calculated, i.e. according to the example a total current of 10A can be used for charge balancing.
• a passive balancing solution can be applied, since in that case excess energy is transformed into heat.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Charge And Discharge Circuits For Batteries Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=89991387

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (10)

• 2014
  • 2014-02-04 HU HU1400051A patent/HUP1400051A3/hu unknown
• 2015
  • 2015-01-26 WO PCT/HU2015/000006 patent/WO2015118364A1/en active Application Filing

Patent Citations (10)

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