Internal power supply of energy storage modules for an energy storage device and energy storage device with such

Abstract

Energy storage module (3) for an energy storage device (1), comprising: an energy storage cell module (5) which has a storage cell series connection of at least two energy storage cells (5a, 5i, 5j, 5k, 5z); a coupling device (7) with a plurality of coupling elements (7a, 7b, 7c, 7d), which is designed to selectively connect or bypass the energy storage cell module (5) in an energy supply line (10a; 10b) of the energy storage device (1); and a driver module (11) designed to generate driver signals for the multitude of coupling elements (7a, 7b, 7c, 7d), wherein the driver module (11) has a first power supply connection (11a) and has a second power supply connection (11b), wherein the first power supply connection (11a) is connected via a first supply line (16a) to a first end connection (9a) of the energy storage cell module (5) and via a second supply line (16b) to a first node between two energy storage cells (5j, 5k) of the storage cell series connection, wherein the second power supply connection (11b) is connected via a third supply line (16c) to a second end connection (9b) of the energy storage cell module (5) and via a fourth supply line (16d) to a second node between two energy storage cells (5i, 5j) of the storage cell series connection, and where the second node lies between the first node and the first terminal (9a).

Description

[0001] The invention relates to an internal energy supply for an energy storage module for an energy storage device and an energy storage device with such an energy storage module, in particular in modularly constructed battery direct converter circuits or battery converter circuits, which are used, for example, in electric drive systems of electrically operated vehicles. State of the art

[0002] It is becoming clear that in the future, both in stationary applications, such as wind turbines or solar power plants, and in vehicles, such as hybrid or electric vehicles, electronic systems will increasingly be used that combine new energy storage technologies with electric drive technology.

[0003] To feed three-phase alternating current into an electric machine, a conventional inverter, specifically a pulse-width modulated inverter, converts the direct current (DC) supplied by a DC link into a three-phase alternating current (AC). The DC link is powered by a string of series-connected battery modules. To meet the power and energy requirements of a given application, several battery modules are often connected in series to form a traction battery. Such an energy storage system is frequently used, for example, in electric vehicles.

[0004] The publication DE 10 2010 041 040 A1 describes an energy storage module for an energy storage device, comprising: an energy storage cell module, which has a series connection of at least two energy storage cells; a coupling device with a plurality of coupling elements, which is designed to selectively connect the energy storage cell module to or bypass an energy supply line of the energy storage device; and a driver module, which is designed to generate driver signals for the plurality of coupling elements.

[0005] The publication DE 10 2011 077 264 A1 discloses a system for converting direct current supplied by energy storage modules into an n-phase alternating current.

[0006] The publication DE 10 2012 216 469 A1 discloses an energy supply system with an energy storage device comprising a plurality of energy storage modules connected in series in at least one energy supply branch, each of which comprises an energy storage cell module having at least one energy storage cell and a coupling device with coupling elements designed to selectively switch the energy storage cell module into or bypass the respective energy supply branch, and a plurality of driver devices, each of which is assigned to and coupled with one of the energy storage modules, and which are designed to control the coupling elements of the coupling devices according to a driver signal.

[0007] The publication describes a battery system with an integrated inverter function. Systems of this type are known as multilevel cascaded inverters or battery direct inverters (BDIs). Such systems comprise DC power sources in multiple energy storage module strings, which can be directly connected to an electric machine or an electrical grid. Single-phase or multi-phase supply voltages can be generated.The energy storage module strings have a plurality of energy storage modules connected in series, each energy storage module having at least one battery cell and an associated controllable coupling unit which allows, depending on control signals, the respective energy storage module string to be interrupted or the respective associated at least one battery cell to be bridged or the respective associated at least one battery cell to be connected to the respective energy storage module string.

[0008] As an alternative, publications DE 10 2010 027 857 A1 and DE 10 2010 027 861 A1 disclose modularly connected battery cells in energy storage devices that can be selectively connected to or disconnected from the string of serially connected battery cells via suitable control of coupling units. Systems of this type are known as Battery Direct Converters (BDCs). Such systems comprise DC sources in an energy storage module string that can be connected to a DC link for the electrical power supply of an electric machine or an electrical grid via a pulse inverter.

[0009] BDCs and BDIs typically exhibit higher efficiency and greater reliability compared to conventional systems. Reliability is ensured, among other things, by the ability to disconnect defective, failed, or underperforming battery cells from the power supply lines through appropriate bridging control of the coupling units.

[0010] The signal and power electronics for the battery cell coupling units can be powered by the battery cells themselves. However, a potential problem arises, for example, during charging, when an interruption occurs in the series connection of the battery cells. This can result in the signal and power electronics no longer receiving power, thus compromising the ability to shut down the coupling units. One solution in such cases is to provide a redundant power supply for the signal and power electronics using external power sources. However, this requires additional implementation effort when connecting the redundant power supply. Disclosure of the invention

[0011] According to one embodiment of the present invention, an energy storage module for an energy storage device comprises an energy storage cell module, which has a series connection of at least two energy storage cells, a coupling device with a plurality of coupling elements designed to selectively connect the energy storage cell module to or bypass the energy supply line of the energy storage device, and a driver module designed to generate driver signals for the plurality of coupling elements. The driver module has a first power supply connection and a second power supply connection.The first power supply connection is connected via a first supply line to a first end connection of the energy storage cell module and via a second supply line to a first node between two energy storage cells in the series connection. The second power supply connection is connected via a third supply line to a second end connection of the energy storage cell module and via a fourth supply line to a second node between two energy storage cells in the series connection. The second node is located between the first node and the first end connection.

[0012] According to a further embodiment, the present invention provides an energy storage device with at least one energy supply line which is coupled between two output terminals of the energy storage device, wherein the energy supply line comprises a plurality of energy storage modules according to the invention connected in series. Advantages of the invention

[0013] One aspect of the present invention is to equip energy storage modules in a series connection of energy storage modules in an energy storage device with modularly constructed power supply strings with a driver module for the coupling elements of the energy storage modules, which is powered by the respective energy storage module. For this purpose, two voltage tap points are provided within the series connection of the energy storage cells of the energy storage module, each of which supplies a power supply connection of the driver module. These voltage tap points represent alternative tap points to the tap points at the end terminals of the series connection of the energy storage cells, so that in the event of a fault within the series connection of the energy storage cells, at least some of the energy storage cells can still contribute to the power supply of the driver module.

[0014] This advantageously allows the driver module to implement safety measures, such as a safety shutdown of the energy storage module, even if there is a fault in the series connection of the energy storage cells.

[0015] On the other hand, the redundant power supply is provided by the energy storage module itself, eliminating the need for additional external power supply components. This saves costs, reduces the installation space, and increases the efficiency of the energy storage system. Furthermore, a significant advantage is the elimination of additional switching regulators for generating the redundant power supply, which in turn reduces manufacturing effort and power losses.

[0016] Secondary advantages of saving on additional redundant switching regulators include improved electromagnetic compatibility (EMC), the avoidance of additional voltage regulators, the elimination of the need for an additional energy source, and the removal of the need to galvanically isolate any additional energy source from the energy storage device.

[0017] According to one embodiment of the energy storage module according to the invention, the coupling devices can each have a plurality of coupling elements in a full bridge configuration. Alternatively, the coupling devices can each have a plurality of coupling elements in a half bridge configuration.

[0018] According to a further embodiment of the energy storage module according to the invention, the energy storage cells can each comprise lithium-ion batteries.

[0019] According to a further embodiment of the energy storage module according to the invention, the energy storage module can comprise a first diode which is arranged in the first supply line, and whose forward direction runs from the first end terminal to the first power supply terminal.

[0020] According to a further embodiment of the energy storage module according to the invention, the energy storage module can have a second diode which is arranged in the second supply line, and whose forward direction runs from the first node to the first power supply connection.

[0021] According to a further embodiment of the energy storage module according to the invention, the energy storage module can comprise a third diode, which is arranged in the fourth supply line, and whose forward direction runs from the second energy supply connection to the second node.

[0022] According to a further embodiment of the energy storage module according to the invention, the driver module can have a signal control circuit coupled between the power supply connections and a driver circuit connected in parallel to the signal control circuit, wherein the signal control circuit is designed to control the driver circuit to generate driver signals for the plurality of coupling elements.

[0023] Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings. Brief description of the drawings

[0024] They show: Fig. 1 a schematic representation of an energy storage device according to an embodiment of the present invention; Fig. 2 a schematic representation of an embodiment of an energy storage module of an energy storage device according to a further embodiment of the present invention; Fig. 3 a schematic representation of a further embodiment of an energy storage module of an energy storage device according to a further embodiment of the present invention; and Fig. 4 a schematic representation of a further energy storage device according to a further embodiment of the present invention;

[0025] Fig. Figure 1 shows an energy storage device 1 for providing a supply voltage by means of parallel-connected energy supply strands 10a, 10b between two output terminals 4a and 4b of the energy storage device 1. The energy supply strands 10a, 10b each have strand terminals 1a and 1b. The energy storage device 1 here has two parallel-connected energy supply strands 10a, 10b. By way of example, the number of energy supply strands 10a, 10b is Fig. 1 two, however any other larger number of energy supply strands 10a, 10b is equally possible. It is equally possible to connect only one energy supply strand 10a between the strand terminals 1a and 1b, which in this case form the output terminals 4a, 4b of the energy storage device 1.

[0026] The power supply lines 10a, 10b can each be coupled to the output terminal 4a of the energy storage device 1 via storage inductors 2a, 2b. The storage inductors 2a, 2b can be, for example, concentrated or distributed components. Alternatively, parasitic inductances of the power supply lines 10a, 10b can also be used as storage inductors 2a, 2b. The power supply lines 10a, 10b can be switchably coupled to the output terminal 4 via a switching coupling device 2c.

[0027] In the case of a single power supply line 10a, the storage inductors 2a or 2b and the switching coupling device 2c can also be omitted, so that the power supply line 10a is directly coupled between the output terminals 4a, 4b of the energy storage device 1.

[0028] Each of the energy supply strings 10a, 10b has at least two energy storage modules 3 connected in series. For example, the number of energy storage modules 3 per energy supply string is... Fig. 1. Two, but any other number of energy storage modules 3 is also possible. Preferably, each of the energy supply strings 10a, 10b comprises the same number of energy storage modules 3, but it is also possible to provide a different number of energy storage modules 3 for each energy supply string 10a, 10b. The energy storage modules 3 each have two output terminals 3a and 3b, via which an output voltage of the energy storage modules 3 can be provided.

[0029] Exemplary configurations of the energy storage modules 3 are shown in the Fig. 2 and Fig. Figure 3 shows in greater detail. The energy storage modules 3 each comprise a coupling device 7 with several coupling elements 7a and 7c, and optionally 7b and 7d. The energy storage modules 3 also each comprise an energy storage cell module 5 with one or more energy storage cells 5a, 5i, 5j, 5k, 5z connected in series.

[0030] The energy storage cell module 5 can, for example, comprise series-connected batteries 5a, 5i, 5j, 5k, 5z, such as lithium-ion batteries or accumulators. The number of energy storage cells 5a to 5k in the module is... Fig. The energy storage module 3 shown in 2 is five by way of example, but any other number of energy storage cells 5a, 5i, 5j, 5k, 5z greater than or equal to two is also possible.

[0031] The energy storage cell modules 5 are connected to input terminals of an associated coupling device 7. The coupling device 7 is in Fig. Figure 2 shows an example of a full bridge circuit with two coupling elements 7a, 7c and two coupling elements 7b, 7d. Each coupling element 7a, 7b, 7c, 7d can have an active switching element, for example a semiconductor switch, and a freewheeling diode connected in parallel. The semiconductor switches can be, for example, field-effect transistors (FETs) or insulated-gate bipolar transistors (IGBTs). In this case, the freewheeling diodes can also be integrated into the semiconductor switches.

[0032] The coupling elements 7a, 7b, 7c, 7d in Fig. 2 can be controlled in this way, for example using the control unit 6 in Fig. 1. The energy storage cell module 5 is selectively connected between the output terminals 3a and 3b, or the energy storage cell module 5 is bypassed or circumvented. By appropriately controlling the coupling devices 7, individual energy storage modules 3 can therefore be selectively integrated into the series connection of an energy supply line 10a, 10b.

[0033] With reference to Fig. 2. For example, the energy storage cell module 5 can be connected in the forward direction between the output terminals 3a and 3b by setting the active switching element of the coupling element 7d and the active switching element of the coupling element 7a to a closed state, while setting the two remaining active switching elements of the coupling elements 7b and 7c to an open state. In this case, a positive module voltage is present between the output terminals 3a and 3b of the coupling device 7. A bridging state can be set, for example, by setting the two active switching elements of the coupling elements 7a and 7b to a closed state, while keeping the two active switching elements of the coupling elements 7c and 7d in an open state.A second bridging state can be set, for example, by closing the two active switches of coupling elements 7c and 7d while keeping the active switching elements of coupling elements 7a and 7b open. In both bridging states, the voltage between the two output terminals 3a and 3b of coupling device 7 is zero. Similarly, the energy storage cell module 5 can be connected in reverse between the output terminals 3a and 3b of coupling device 7 by closing the active switching elements of coupling elements 7b and 7c while opening the active switching elements of coupling elements 7a and 7d. In this case, a negative module voltage is present between the two output terminals 3a and 3b of coupling device 7.

[0034] The total output voltage of a power supply string 10a, 10b can be set in steps, with the number of steps scaling with the number of energy storage modules 3. With n first and second energy storage modules 3, the total output voltage of the power supply string 10a, 10b can be set in 2n+1 steps.

[0035] The coupling elements 7a, 7b, 7c, 7d of an energy storage module 3 can also be controlled by pulsed control, for example in pulse width modulation (PWM), so that the energy storage module 3 delivers, on average over time, a module voltage which can have a value between zero and the maximum possible module voltage determined by the energy storage cells 5a to 5z. The control of the coupling elements 7a, 7b, 7c, 7d can be carried out, for example, by a control unit such as the control unit 6 in Fig. 1, which is designed to, for example, perform current control with a subordinate voltage control, so that individual energy storage modules 3 can be switched on or off in stages.

[0036] The energy storage cell module 5 serves not only to provide a module output voltage but also to supply a driver module 11 with energy from the energy storage cells 5a, 5i, 5j, 5k, 5z. For this purpose, the driver module 11 is connected to the output terminals 9a and 9b of the energy storage cell module 5 via power supply connections 11a and 11b, respectively. During normal operation of the energy storage module, the module output voltage is present between output terminals 9a and 9b of the energy storage cell module 5 and is supplied to the driver module 11 via a first supply line 16a and a third supply line 16c.

[0037] The driver module 11 can, for example, include a pre-stabilizer 12 and a stabilizer 13, which serve to stabilize the supply voltage for the driver module 11. The stabilizer 13 is connected to a parallel circuit consisting of a driver circuit 14 and a signal control circuit 15. The signal control circuit 15 is designed to control the driver circuit to generate control signals for the coupling elements 7a to 7d of the coupling device 7. The signal control circuit 15 can, for example, include a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable logic gate (FPGA), or another logic circuit.The pre-stabilizer 12 and the stabilizer 13 can, for example, include filter circuits or transformer circuits suitable for ensuring a suitably adapted and low-fluctuation supply voltage for the driver circuit 14 and the signal control circuit 15.

[0038] In addition to the first supply line 16a, the first power supply connection of the driver module 11 is connected via a second supply line 16b to a first node between two energy storage cells 5j and 5k of the series connection of energy storage cells 5a to 5z. Likewise, the second power supply connection 11b, in addition to the third supply line, is connected via a fourth supply line 16d to a second node between two energy storage cells 5i and 5j of the series connection of energy storage cells 5a to 5z. The second node is located between the first node and the first end connection 9a. In other words, the second and fourth supply lines 16b and 16d, respectively, serve as redundant supply lines to the first and third supply lines 16a and 16d, respectively.16c, if a fault should occur in the series circuit of energy storage cells 5a to 5z, for example if one of the energy storage cells 5a to 5z should fail.

[0039] The nodes divide the series connection of energy storage cells 5a to 5z into two sections, a lower and an upper section. Because the first node lies between the first termination 9a and the second node, the lower and upper sections formed by the (virtual) division each have overlapping areas, to which the same energy storage cells belong. In the example of the Fig. 2. Such an overlapping area is formed by the energy storage cell 5j, which lies between the first and second nodes. The overlapping area can, of course, also contain more than one energy storage cell 5j.

[0040] Within the non-overlapping subsections of the upper and lower sections, there are disjoint groups of energy storage cells. For example, the upper section contains energy storage cells 5a to 5i, which are distinct from energy storage cells 5k to 5z forming the lower section. The number of energy storage cells in these disjoint groups can range from one to any number adapted to the specific requirements.

[0041] Supply lines 16a, 16b, and 16d each have a diode 17a, 17b, and 17d, respectively. These diodes ensure that the correct polarity is present at the power supply terminals 11a and 11b of the driver module 11. A first diode 17a is arranged in the first supply line 16a, such that its forward direction runs from the first terminal 9a to the first power supply terminal 11a. Similarly, a second diode 17b is arranged in the second supply line 16b, such that its forward direction runs from the first node to the first power supply terminal 11a. Finally, the fourth supply line 16d has a third diode 17d, whose forward direction runs from the second power supply terminal 11b to the second node.

[0042] Under normal operating conditions, that is, without any fault or defect in the series-connected energy storage cells, the supply current for the driver module 11 always flows through the first diode 17a. However, if the current path is interrupted in the upper section of the series-connected energy storage cells formed by cells 5a to 5i, the driver module 11 is powered via the second diode 17b and the second supply line 16b. Conversely, if the current path is interrupted in the lower section of the series-connected energy storage cells formed by cells 5k to 5z, the driver module 11 is powered via a supply current through the third diode 17d and the fourth supply line 16d. If the current path between the two nodes is interrupted, the driver module 11 is powered by the section of energy storage cells with the higher nominal voltage.

[0043] In any case, the driver module 11 can always be supplied from at least some of the energy storage cells 5a to 5z, regardless of where a defect occurs in the series connection of the storage cells. The generation of the supply voltage can be started in a conventional manner via a wake-up mechanism.

[0044] Fig. Figure 3 shows another exemplary embodiment of an energy storage module 3. The one in Fig. The energy storage module shown in Figure 3 differs from the one in Figure 3. Fig. The energy storage module 3 shown in Figure 2 differs only in that the coupling device 7 has two coupling elements instead of four, which are connected in a half-bridge circuit instead of a full-bridge circuit.

[0045] In the illustrated embodiments, the active switching elements can be implemented as power semiconductor switches, for example in the form of IGBTs (Insulated Gate Bipolar Transistors), JFETs (Junction Field-Effect Transistors), or MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors). The driver circuit 14 can be a gate driver circuit for generating gate signals for the power semiconductor switches. Because the driver circuit 14 is always supplied with energy from at least some of the energy storage cells 5a to 5z in the energy storage cell module 5, even in the event of a fault, the bypass switches of a respective half-bridge can be opened in the event of a fault to divert the current around the energy storage cell module 5 and prevent overloading of the energy storage cell module 5 or the coupling elements 7a, 7b, 7c, 7d of an energy storage module 3.This can be done, for example, during the charging operation of the energy storage module 3, in order to eliminate the risk of fire in the energy storage device 1 in the event of uncontrolled input of charging current into a defective energy storage cell module 5.

[0046] Fig. Figure 4 shows an electric drive system 100 with an additional energy storage device 1 for converting the DC voltage provided by energy storage modules 3 into an n-phase AC voltage. The energy storage device 1 comprises energy storage modules 3, which are connected in series in power supply strings 10a, 10b, 10c. Examples are shown in Fig. Figure 4 shows three power supply strands 10a, 10b, 10c, which are suitable for generating a three-phase alternating voltage, for example for a three-phase machine. However, it is clear that any other number of power supply strands is also possible. The energy storage device 1 has an output connection 4d, 4e, 4f on each power supply strand.

[0047] The energy supply strings 10a, 10b, 10c are each connected at their ends to output terminals, which in turn can be connected, for example, to a reference potential 4. The energy storage modules 3 of the energy storage device 1 in Fig. 4 can in particular according to one of the embodiments of the Fig. 2 and Fig. 3 be designed so that the energy supply strings 10a, 10b, 10c can be modularly configured from a series connection of similar energy storage modules 3. The control of the coupling devices 7 can be similar to that in Fig. 1 thereby operate a control device 6 of the energy storage device 1.

[0048] The energy storage device 1 has integrated inverter functionality, so that the output terminals 4d, 4e and 4f can be directly connected to phase lines 8a, 8b, 8c of the three-phase electric machine 8. The energy storage device serves as an example in Fig. 4 for supplying a three-phase electric machine 8 with respective machine chokes 8d, which are connected to each other, for example, at a star point. However, it can also be provided that the energy storage device 1 is used to generate electrical current for a power supply network. Alternatively, the electric machine 8 can also be a synchronous or asynchronous machine, a reluctance machine, or a brushless DC motor (BLDC). It may also be possible to use the energy storage device 1 in stationary systems, for example, in power plants, in electrical energy generation plants such as wind turbines, photovoltaic systems, or combined heat and power plants, in energy storage systems such as compressed air energy storage plants, battery storage plants, flywheel energy storage systems, pumped storage plants, or similar systems. Another possible application of the drive system 100 in Fig.4 are passenger or goods transport vehicles designed to move on or under water, for example ships, motorboats or the like.

Claims

[1] Energy storage module (3) for an energy storage device (1), comprising: an energy storage cell module (5) which has a storage cell series connection of at least two energy storage cells (5a, 5i, 5j, 5k, 5z); a coupling device (7) with a plurality of coupling elements (7a, 7b, 7c, 7d), which is designed to selectively connect or bypass the energy storage cell module (5) in an energy supply line (10a; 10b) of the energy storage device (1); and a driver module (11) designed to generate driver signals for the multitude of coupling elements (7a, 7b, 7c, 7d), wherein the driver module (11) has a first power supply connection (11a) and has a second power supply connection (11b), wherein the first power supply connection (11a) is connected via a first supply line (16a) to a first end connection (9a) of the energy storage cell module (5) and via a second supply line (16b) to a first node between two energy storage cells (5j, 5k) of the storage cell series connection, wherein the second power supply connection (11b) is connected via a third supply line (16c) to a second end connection (9b) of the energy storage cell module (5) and via a fourth supply line (16d) to a second node between two energy storage cells (5i, 5j) of the storage cell series connection, and where the second node lies between the first node and the first terminal (9a). [2] Energy storage module (3) according to claim 1, wherein the coupling devices (7) each have a plurality of coupling elements (7a, 7b, 7c, 7d) in full bridge configuration. [3] Energy storage module (3) according to claim 1, wherein the coupling devices (7) each have a plurality of coupling elements (7a, 7c) in a half-bridge circuit. [4] Energy storage module (3) according to any one of claims 1 to 3, wherein the energy storage cells (5a, 5i, 5j, 5k, 5z) each comprise lithium-ion batteries. [5] Energy storage module (3) according to any one of claims 1 to 4, further comprising: a first diode (17a) which is arranged in the first supply line (16a) and whose forward direction runs from the first end terminal (9a) to the first power supply terminal (11a). [6] Energy storage module (3) according to any one of claims 1 to 5, further comprising: a second diode (17b) which is arranged in the second supply line (16b) and whose forward direction runs from the first node to the first power supply connection (11a). [7] Energy storage module (3) according to any one of claims 1 to 6, further comprising: a third diode (17d) which is arranged in the fourth supply line (16d) and whose forward direction runs from the second power supply connection (11b) to the second node. [8] Energy storage module (3) according to any one of claims 1 to 7, wherein the driver module (11) has a signal control circuit (15) coupled between the power supply terminals (11a; 11b) and a driver circuit (14) connected in parallel to the signal control circuit (15), wherein the signal control circuit (15) is designed to control the driver circuit (14) to generate driver signals for the plurality of coupling elements (7a, 7b, 7c, 7d). [9] Energy storage device (1), comprising: at least one power supply line (10a; 10b) which is coupled between two output terminals (4a, 4b; 4d, 4e, 4f) of the energy storage device (1), wherein the power supply line (10a; 10b) comprises a plurality of series-connected energy storage modules (3) according to one of claims 1 to 8.

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