WO2014020223A1 - Rechargeable electrical voltage supply system - Google Patents

Description

 RECHARGEABLE ELECTRIC VOLTAGE SUPPLY SYSTEM

The present invention relates to a rechargeable electric voltage supply system that optimizes energy utilization by non-resistive balancing of the system's battery cells.

Background of the invention

Rechargeable electric voltage supply systems are known, comprising a battery provided with a plurality of cells connected in series, a voltage output intended for a charge, a voltage input for recharging, a first converter module disposed between the battery and the output and sensors of physical variables of the battery that reflect its state of charge.

 This is the case of WO201 150191, which is considered to be the closest state of the art and in which a battery charging balancing device is provided provided with protection circuits against the reversal of battery cell polarity.

 In WO2011070517 an active balancing of the redistribution of energy provided with reactive elements, such as transformers or inductors, which transfer energy between cells is used. There is no disconnection or an output with voltage levels

staggered nor the converter control system from signals of the management device of said active elements.

 In IT2009VI0254 (WO201 1047741) and WO201 1042243, similar to the previous one, balancing devices by dissipative elements are described.

 However, all these devices use resistors arranged in parallel with the cell, with the energy losses that this entails.

Description of the invention

To overcome the aforementioned drawback of the technique, the present invention proposes a rechargeable electric voltage supply system, comprising:

 a battery provided with a plurality of cells connected in series;

 a voltage output intended for a load;

 a voltage input for recharging;

 a first converter module arranged between the battery and the output;

- sensors of physical variables of the battery that reflect its state of charge;

characterized by the fact that it comprises controlled by-pass circuits of the cells and a battery management device of the circuits that receive signals from the sensors, so that it is possible to balance the state of charge of the cells obtaining a variable voltage at the output of the battery that can be adapted to the voltage output through the first converter.

Preferably, the system comprises feedback loops and communication bus between the control device and the converter modules, so that they can know in advance the voltage variations and better adapt their operation to the variations in the battery voltage.

 Advantageously, the system comprises a second converter module arranged between the input and the battery, obtaining a variable voltage at the output of the battery that can be adapted to the input by means of the second converter.

 According to a variant of the system, each of the cell by-pass controlled circuits comprises a controlled cell switch, a controlled bypass switch and a diode arranged in parallel.

According to another variant, each of the cells controlled by-pass circuits comprises a controlled cell switch, and a diode arranged in parallel.

 More advantageously, the system comprises for each controlled circuit a drive driver circuit, which is controlled by the battery management device.

 Preferably, the system comprises for each controlled circuit a conditioning circuit of the signals coming from the physical variable sensors of the battery.

 Advantageously, the signals from the physical variable sensors of the battery are Voltage, Current and / or Temperature.

 Finally, the following components can be integrated into a single block:

 - Battery;

 the sensors;

 the controlled circuits;

 the first and / or the second converter module;

The invention also relates to a vehicle provided with a system according to any of the variants of the invention described.

Brief description of the figures

To better understand how much has been exposed, some drawings are attached in which, schematically and only by way of non-limiting example, a practical case of realization is represented. Figure 1 schematically represents a balancing circuit according to the invention. Figure 2 represents a simplified version of the balancing circuit.

Figure 3 represents the integration of the converter modules and the balancing system, with a feedback loop with the load.

Description of preferred embodiments

A typical electrical architecture of an electric vehicle is illustrated in Figure 1. In it you can distinguish the main modules:

 4: AC-DC converter module: this converter module charges the battery from the G power grid or any other type of electric power source, photovoltaic plate, fuel cell. Usually the AC-DC converter functions as an active corrector of the power factor (in English Power Factor Corrector, PFC). If the converter is bidirectional, it can also inject power into the mains.

3: Converter module: 1 ^to Option: DC-AC converter, this module is responsible for driving motor 2;

2 ^a Option: DC-DC converter, the converter guarantees a regulated DC voltage at the motor drive input. In both cases, if the converter is bidirectional, it can inject energy into the battery from the motor: operation as regenerative braking. 1: MAE Energy Storage Module: consisting of the battery or battery pack, or any energy storage technology that requires balancing, such as supercapacitors. In general, it also includes a battery management module 6 and an active or passive balancing system, such as those described in the background, for example.

As can be seen in Figure 1, the invention relates to a rechargeable electric voltage supply system, comprising: a battery 1.1 provided with a plurality of connected cells CA _X I, CA _X 2, ■■■ CA _XP serially;

a voltage output V ₀ destined for a load 2;

 a voltage input V | for recharging;

a first converter module 3 disposed between battery 1 and output V ₀ ; sensors 5 of physical variables of battery 1.1 that reflect its state of charge; Specifically, as seen in Figure 1, the system of the invention comprises circuits EM UA _X I, EM UA _X 2, ■■■ ΕΜ ΙΙΑ _ΧΠ controlled bypass of the cells CA _X I, CA _X 2 , ... CA _XP and a battery management device 6 of the circuits EM UA _X I, EM UA _X 2, ■■■ EMUAxn that receives signals from the sensors 5, so that it is possible to balance the state of _X charging CA I, CA _X 2 ■■■ CA _XH cells yielding a variable voltage Vf _n ta the battery output 1.1 can be adapted to the output voltage V ₀ by the first converter 3.

 It is emphasized that in the present description battery encompasses both the cells that supply voltage and the EM U circuits bypass the cells.

According to a particularly preferred embodiment, a second converter module 4 provided between the input V | and battery voltage 1.1 V , resulting in a variable _nt to 1.1 battery output that can be adapted to the input V | by the second converter 4.

A feedback loops C1, C2 and a communication bus between the control device 6 and the converter modules 3, 4, so that they can know beforehand the variations of Vf _nt and better adapt its operation is also made to Variations in battery voltage 1.1.

Each of the EMUA _X I, EM UA _X 2, ■■■ EM UAxn controlled by-pass circuits of the CA _X I, CA _X 2, ■■■ CA _XP circuits comprises an SDA _X I controlled cell switch, SDA _X 2, ■■■ SDA _XP , a controlled bypass switch SCA _X I, SCA _X 2, ■■■ SCA _XP and a diode DA _X I, DA _X 2, ■■■ DA _XP arranged in parallel.

As shown in Figure 2, the circuits EM UA _X I, EM UA _X 2, ■■■ EMUA _XP by-pass controlled cells CA _X I, CA _X 2, ■■■ CA _XP can be implemented with a controlled cell switch SDA _X I, SDA _X 2, ■■■ SDA _XP , and a diode DA _X I, DA _X 2, ■■■ DA _XP arranged in parallel.

As shown in Figure 1, each EM UA _X I, EM UA _X 2, ■■■ EM UA _XP controlled circuit comprises a GDUA _X I, GDUA _X 2 drive driver circuit, ■■■ GDUA _XP , which is controlled by the battery management device 6.

Likewise, for each circuit EM UA _X I, EM UA _X 2, ■■■ EM UA _XP controlled a conditioning circuit AUA _X I, AUA _X 2, ■■■ AUA _XP of the signals coming from the sensors 5 of variables Battery physics 1.1.

 The signals from the sensors 5 of physical variables of the battery 1.1 are of Voltage VCAXI, VCAX2, ■■■ VCAXH, Current ICAXI, ICAX2, ■■■ ICAXH and / or Temperature TCAXI, TCAX2, ... TCAXÜ-

Likewise, the SCA _XP and SDA _XP bypass controlled switches can be provided with a protection circuit to prevent overvoltages.

As shown schematically in Figure 3, the C blocks are integrated into following components:

 the battery 1.1;

 the sensors 5;

 the controlled circuits EM UAXI, EM UAX2, ■■■ EM UA ™;

 - the first 3 and / or the second 4 converter module;

so that the set C is externally appreciated as a battery that supplies a constant voltage.

MODES OF OPERATION OF THE PROPOSED SYSTEM (EXAMPLE OF

APPLICATION FOR ELECTRIC VEHICLE)

There are several modes of operation of the proposed balancing system that can be classified, in general, according to the sign of the battery current (ie if the battery is charging IBAT> 0 or if IBAT <0 is being discharged) and origin of the energy (ie if the energy comes from the motor, from the mains or from the battery itself). Taking these situations into account, four operating modes can be defined (table I):

 M1 mode: Balanced during battery charging through the mains M2 mode: Balanced during battery charging through the engine, regenerative braking

 M3 mode: Balanced during battery discharge, feeds the engine

 M4 mode: Balanced during battery discharge to inject power into the mains

 Table I: Operating modes of the balancing system

 Mode Mode

Battery Operating source operation

Mode Description

 Power Converter Bidirectional converter 4 Bidirectional 3

 Converter 3 no

Typical load works. In these networks from a moment the engine

M1> 0, load As AC-DC, PFC

 electric socket does not work, the vehicle current is stopped charging

Braking Converter 4 no

 Regenerative: works. In these AC-DC, i.e. the

M2> 0, Motor load the engine moments the engine power goes from the engine works as it works, the vehicle to the battery. generator. is on the move and

can't be connected to the socket

 of the power grid

 Converter 4 no

 The engine is

 works. In these

 feed

 moments the engine

 from DC-AC

<or, the vehicle works

 M3 battery battery a

 download is in motion and Drive through the

 can't be converter motor

 connected to the socket

 bidirectional 3

 of the power grid

 In this case it works

 as DC-AC, the right now

<or, the battery yields power goes from the port the engine does not work,

M4 battery

 Discharge the output network (DC) to the vehicle this input port stopped.

 (AC)

The balancing of the battery cells can be performed in any of the operating modes described in Table I. Figure 1 illustrates the generic balancing circuit that can operate in any of the 4 modes mentioned above. It is also possible, for reasons of cost, that the balancing is carried out in groups of 2 more cells, that is to say that the component referenced as C _Axn represents a set of two or more cells.

Operation of the converters in each operating mode:

M1- The battery is charged through the Bidirectional Converter 4. This converter acts as an AC-DC converter. The bidirectional converter can be an individual AC-DC converter or it can be the result of the interconnection of several modular converters, either through a cascade, parallel or other connection.

M2- The battery is charged through the Bidirectional Converter 3: operation of the electric machine as a generator This converter acts as an AC-DC converter. The bidirectional converter can be an individual AC-DC converter or it can be the result of the interconnection of several modular converters, either through a cascade connection, in parallel or other

M3- The battery is discharged through the bidirectional converter 3: operation of the electric machine as a motor. The bidirectional converter can be an individual DC-AC converter or it can be the result of the interconnection of several modular converters, either through a cascade, parallel or other connection.

M4- The battery is discharged through the Bidirectional Converter 4 (in this case the battery It supplies power to the power grid.

As can be seen from Figure 1, two communication buses C1 and C2 are provided. Through these buses the battery management module 6 sends information to the converter modules. For example, the battery management module 6 may notify the converter modules that a battery voltage disturbance will occur. In this way the converter modules can prepare the necessary control action to compensate for the voltage variation. At the same time the battery management module 6 can receive information from the converter modules informing that at any given moment it is not convenient to perform any balancing or the opposite, which at that time is the ideal time to do so. For example, it may be the case of a vehicle stopped at a traffic light.

SIMPLIFIED BALANCED MODE The simplest balancing mode is balancing in the download mode. This is because the EMU circuit only needs a two-way SDaxn switch and a Daxn diode. This is the easiest and most economical way to implement the proposed balancing system. Figure 2 illustrates the EMU circuit associated with this balancing mode. However, it can happen, for example, that one of the cells has degraded excessively reducing its capacity. In this sense, the state of full load would be reached at a different time than the rest. Thus, it is necessary to bypass this cell, during loading, opening SD and closing SC. This requires the switch SC of the variant illustrated in Figure 1.

The same would happen in the event that a damaged cell discharges much faster than the others, in this sense they would be disabled or bypassed during the battery discharge process. This maneuver can be done with both the full version and the simplified version.

Finally, a damaged cell should be able to be disconnected permanently by keeping SC closed and SD open indefinitely. In this case, the switch SC of the variant illustrated in figure 1 is needed. In summary, it can be seen that the generic circuit EM UA _XP of figure 1 although it has a greater number of elements would be the one that would provide better system performance even by providing a certain degree of fault tolerance when one or more cells were damaged. As illustrated in Figure 3, a total integration into the storage system of all converter modules of Figure 1 is provided. In this way, the assembly C would be viewed from the outside as a system with an input and an output With capacity to house a certain amount of energy. At the input the AC power grid or a DC bus could be connected and at the output, the load could be connected. The load could be direct current (motor electric drive input) or alternating current (assuming that the AC motor drive is also integrated in module C). Internally, the balancing of the battery cells by the invention would be ensured.

 In this case C, the motor drive can be integrated, hence it is necessary to provide the feedback loop C3 shown in Figure 3.

 In addition, the system would have the ability to receive and send the information of the load or the electrical network for the performance of certain tasks

An interesting alternative option would be the following:

 The system would have integrated the converter module 3, the battery, the balancing system and the converter module 4. The converter module 4 would be bi-directional and would allow the battery to be charged / discharged from / to the network. The converter module 3 would regulate the output voltage regardless of the disturbances introduced by the balancing system when bypassing cells. In this way the load would not distinguish between the output of a battery and the output of the converter module. The difference from the previous case lies in the fact that C does not include the converter that performs the motor drive.

Although reference has been made to a specific embodiment of the invention, it is apparent to one skilled in the art that the described system is susceptible of numerous variations and modifications, and that all the mentioned details can be replaced by other technically equivalent ones, without departing from the scope of protection defined by the appended claims.

Claims

1. Rechargeable electric voltage supply system, comprising: - a battery (1.1) provided with a plurality of cells (CA _X I, CA _X 2, ■■■ CA _XP ) connected in series; a voltage output (V ₀ ) intended for a load (2);  a voltage input (V |) for recharging; a first converter module (3) disposed between the battery (1.1) and the output (V ₀ ); sensors (5) of physical variables of the battery (1.1) that reflect its state of charge; characterized by the fact that it comprises circuits (EMUA _X I, EM UA _X 2, ■■■ ΕΜ ΙΙΑ _ΧΠ ) controlled by-pass cells (CA _X I, CA _X 2, ■■■ CA _XP ) and a battery management device (6) of the circuits (EM UA _X I, EM UA _X 2, ■■■ EM UAxn) that receives signals from the sensors (5), so that it is possible to balance the state of load cells (CA _X I, _X 2 CA, CA ■■■ _XP) to give a variable voltage (Vf _nt) at the output of the battery (1.1) which can be adapted to the output voltage (V ₀₎ by the first converter (3). 2. System according to claim 1, comprising feedback loops and communication bus between the battery management device (6) and the converter modules (3, 4), so that they can know in advance the variations of ( Vt _nt) and better adapt its operation to variations in the voltage of the battery (1). 3. System according to any of the preceding claims, comprising a second willing converter (4) between the input (V |) and battery (1.1) to give a variable voltage (Vf _nt) at the output of the battery (1.1 ) that can be adapted to the input (V |) by the second converter (4). 4. System according to any of the preceding claims, wherein each of the circuits (EM UAXI, EM UAX2, ■■■ EM UAxn) controlled by-pass cells (CAXI, CAX2, ■■■ CA _XP ) they comprise a controlled cell switch (SDA _X I, SDA _X 2, ■■■ SDA _XP ), a controlled bypass switch (SCAXI, SCAX2, ■■■ SCAXP) and a diode (DAXI, DAX2, ■■■ DAXP) arranged in parallel. 5. System according to any one of claims 1 to 3, wherein each of the circuits (EM UAXI, EM UAX2, ■■■ ΕΜ ΙΙΑΧΠ) controlled by-pass cells (CAXI, CAX2, ■■■ CA _XP ) comprise a controlled cell switch (SDA _X I, SDA _X 2, ■■■ SDA _XP ), and a diode (DA _X I, DA _X 2, ■■■ DA _XP ) arranged in parallel. 6. System according to any of the preceding claims, comprising for each circuit (EM UA _X I, EM UA _X 2, ■■■ EMUAxn) controlled a driver driver circuit (GDUA _X I, GDUA _X 2, ■■■ GDUAxn ), which is controlled by the battery management device (6). 7. System according to any of the preceding claims, comprising for each circuit (EM UA _X I, EM UA _X 2, ■■■ EMUAxn) controlled a conditioning circuit (AUA _X I, AUA _X 2, ■■■ ΑΙΙΑ _ΧΠ ) of the signals coming from the sensors (5) of physical variables of the battery (1.1). System according to any of the preceding claims, in which the signals from the sensors (5) of physical variables of the battery (1.1) are of Voltage (VCAXI, VCAX2, ... VCAXH), Current (ICAXI, ICAX2 , ... ICAXH) and / or Temperature (TCAXI, TCAX2, ... TCAXÜ). 9. System according to any of the preceding claims, wherein the following components are integrated into a single block (C):  the battery (1.1);  the sensors (5);  the controlled circuits (EM UAXI, EM UAX2, ■■■ EMUAxn);  - the first (3) and / or the second (4) converter module; 10. Vehicle provided with a system according to any of the preceding claims.