Device for adjusting the self-discharge rate of at least one electrochemical energy storage cell of a plurality of electrochemical energy storage cells of an electrochemical energy storage system

Abstract

Device for adjusting the self-discharge rate of at least one electrochemical energy storage cell of a plurality of electrochemical energy storage cells of an electrochemical energy storage device.

Description

[0001] The invention is based on a device for adjusting a self-discharge rate of at least one electrochemical energy storage cell of a plurality of electrochemical energy storage cells of an electrochemical energy storage device, a method for operating the device and a use of the device according to the preamble of the independent claims. State of the art

[0002] Manufacturing influences and different rates of aging of battery cells affect, among other things, the internal resistance and self-discharge rate of the battery cells.

[0003] Within a battery pack, this can lead to different charge levels of the battery cells. These differences must be compensated for by battery cell balancing in order to store more energy in the battery pack.

[0004] According to the current state of the art, passive balancing is used for battery cell balancing, in which fuller battery cells are discharged via balancing resistors, and the excess energy is converted into heat. These balancing resistors are typically located in a (sub-)control unit.

[0005] This battery cell balancing is necessary, but passive balancing leads to energy waste because excess electrical energy is converted into waste heat.

[0006] The document KR 2013 / 0100523 A discloses a system for balancing battery modules.

[0007] Document US 2013 / 307480 A1 discloses a system and method for providing energy management and maintenance of a high-energy battery pack through the use of self-discharge functions and processes. A battery pack is configured with self-discharging components that selectively discharge energy from the battery pack without the battery pack supplying operating power.

[0008] The object of the present invention is to further improve the state of the art. This object is achieved by the features of the independent claims. Disclosure of the inventionAdvantages of the invention

[0009] The procedure according to the invention with the characterizing features of the independent claims has the advantage that the device for adjusting a self-discharge rate of at least one electrochemical energy storage cell of a plurality of electrochemical energy storage cells of an electrochemical energy storage device comprises: - a plurality of electrical resistors, wherein the electrical resistors can be connected in parallel to the electrochemical energy storage cells by means of switches in order to convert electrical energy into heat; - a plurality of heat conducting devices for heat transfer of the generated heat by means of heat conduction, wherein the heat conducting devices are thermally coupled to the electrical resistors and the electrochemical energy storage cells; whereby a higher thermal load of the at least one electrochemical energy storage cell is achieved and the self-discharge rate of the at least one electrochemical energy storage cell is adjusted.

[0010] Advantageously, excess waste heat generated when balancing the charge states is used for energy purposes and does not have to be dissipated through, for example, complex housing concepts.

[0011] Further advantageous embodiments are the subject of the subclaims.

[0012] Equalizing the self-discharge rate of the at least one electrochemical energy storage cell represents increasing the self-discharge rate to a substantially equal self-discharge rate of other electrochemical energy storage cells of the plurality of electrochemical energy storage cells.

[0013] Advantageously, the device according to the invention achieves a substantially equal self-discharge rate of the electrochemical energy storage cells, thereby reducing the need for equalizing the charge states of the electrochemical energy storage cells.

[0014] The electrical resistors are arranged in close proximity to the electrochemical energy storage cells and / or spatially separated, preferably on a flexible circuit board

[0015] The electrical resistors include ohmic resistors, preferably heating resistors or electrically conductive foils with a predetermined resistance.

[0016] The heat conducting devices comprise at least partially a material with high thermal conductivity, preferably made of a metal with low electrical resistance, in particular copper or aluminum, and / or low electrical conductivity, in particular heat conducting foils, heat conducting paste and / or heat conducting adhesive.

[0017] A method according to the invention for adjusting a self-discharge rate of at least one electrochemical energy storage cell of a plurality of electrochemical energy storage cells of an electrochemical energy storage device comprises the following steps: a) detecting voltage quantities which represent an electrical voltage of the electrochemical energy storage cells at a substantially identical point in time; b) comparing the recorded voltage values; c) controlling at least one switch depending on the comparison in order to convert electrical energy into heat by means of at least one electrical resistor and to actively adjust the self-discharge rate for the at least one electrochemical energy storage cell by means of a higher thermal load.

[0018] A control device according to the invention comprises means for carrying out the method according to the invention for adjusting a self-discharge rate of at least one electrochemical energy storage cell of a plurality of electrochemical energy storage cells of an electrochemical energy storage device.

[0019] According to an advantageous embodiment of the invention, a computer program is provided, comprising instructions which cause the device for adjusting a self-discharge rate of at least one electrochemical energy storage cell of a plurality of electrochemical energy storage cells of an electrochemical energy storage device to carry out the method steps according to the invention.

[0020] Furthermore, a machine-readable storage medium is provided on which the computer program is stored.

[0021] The device according to the invention and / or the method according to the invention are advantageously used in electrical energy storage devices for electric vehicles, fuel cell vehicles, hybrid vehicles, plug-in hybrid vehicles, aircraft, pedelecs or e-bikes, for portable devices for telecommunications or data processing, for electrical hand tools or kitchen appliances, as well as in stationary storage devices for storing, in particular, electrical energy generated from renewable sources. Short description of the characters

[0022] Embodiments of the invention are illustrated in the drawing and explained in more detail in the following description.

[0023] They show: Fig. 1 is a schematic representation of a first embodiment of a device according to the invention; and Fig. 2 is a schematic representation of a second embodiment of a device according to the invention; and Fig. 3 a schematic representation of a third embodiment of a device according to the invention. Detailed description of the implementation examples

[0024] The same reference numerals denote the same device components in all figures.

[0025] Fig. 1 shows a schematic representation of a first embodiment of a device 102 according to the invention. An electrochemical energy storage device 100 comprises a plurality of electrochemical energy storage cells 101. Each electrochemical energy storage cell 101 is thermally coupled to an electrical resistor 103 by means of a heat-conducting device 104. The electrical resistors 103 are arranged, for example, on one side of the electrochemical energy storage cells 101 and / or on a top side of the electrochemical energy storage cells 101, preferably on a flexible printed circuit board.

[0026] The electrical resistors 103 can be connected in parallel to the electrochemical energy storage cells by means of a switch 107 to convert electrical energy into heat. Advantageously, the electrical voltage of the electrochemical energy storage cells 101 can be actively limited to a predeterminable electrical voltage, for example, a final charging voltage or another predeterminable electrical voltage.

[0027] In the embodiment shown, the electrochemical energy storage cell 105 has a lower self-discharge rate than the other electrochemical energy storage cells 101. As a result, the electrochemical energy storage cell 105 reaches the end-of-charge voltage or a predeterminable electrical voltage more quickly during a charging process with a predetermined charging current and has the highest electrical voltage and the highest state of charge of the electrochemical energy storage cells 101. The switch 108 is closed, causing electrical current to flow through the electrical resistor 103 and electrical energy to be converted into heat.

[0028] This heat is supplied to the electrochemical energy storage cell 105 via heat conduction devices 104, thereby subjecting it to thermal stress. This thermal stress leads to a higher self-discharge rate of the electrochemical energy storage cell 105.

[0029] As a result, the self-discharge rate of the electrochemical energy storage cell 105 approximates to a higher level of a self-discharge rate of the electrochemical energy storage cells 101.

[0030] In an embodiment not shown, the electrical resistors 103 can each be electrically connected in parallel with the electrochemical energy storage cells 101. Adjusting the state of charge of the electrochemical energy storage cell 105 leads to a higher self-discharge rate due to a higher thermal load, thereby reducing the frequency of adjusting the state of charge.

[0031] Advantageously, the substantially equal self-discharge rates reduce the need to equalize charge states of electrochemical energy storage cells 101 of the electrochemical energy storage device 100.

[0032] Ideally, cooling is turned off during the process of adjusting a self-discharge rate of the electrochemical energy storage cell 105 to enhance an effect of the thermal stress and increase efficiency.

[0033] Fig. Figure 2 shows a schematic representation of a second embodiment of a device 202 according to the invention. An electrochemical energy storage device 200 comprises a plurality of electrochemical energy storage cells 201. Each electrochemical energy storage cell 201 comprises a heat-conducting device 204 and an electrical resistor 203 within the electrochemical energy storage cell 201. The electrical resistors 203 are thermally coupled to the electrochemical energy storage cells 201 by means of the heat-conducting devices 204. The efficiency can be advantageously increased by the arrangement within the electrochemical energy storage cell 201.

[0034] The electrical resistors 203 can be switched in parallel to the electrochemical energy storage cells by means of switch 207 in order to convert electrical energy into heat.

[0035] In the embodiment shown, the electrochemical energy storage cell 205 has a lower self-discharge rate than the other electrochemical energy storage cells 201. As a result, the electrochemical energy storage cell 205 reaches the end-of-charge voltage more quickly during a charging process with a predetermined charging current and has the highest state of charge of the electrochemical energy storage cells 201. The switch 208 is closed, causing electrical current to flow through the electrical resistor 203 and electrical energy to be converted into heat.

[0036] This heat is supplied to the electrochemical energy storage cell 205 via heat conduction devices 204, thereby subjecting it to thermal stress. This thermal stress leads to a higher self-discharge rate of the electrochemical energy storage cell 205.

[0037] As a result, the self-discharge rate of the electrochemical energy storage cell 205 approximates to a higher level of a self-discharge rate of the electrochemical energy storage cells 201.

[0038] In an embodiment not shown, the electrical resistors 203 can each be electrically connected in parallel with the electrochemical energy storage cells 201. Adjusting the state of charge of the electrochemical energy storage cell 205 leads to a higher self-discharge rate due to a higher thermal load, thereby reducing the need for adjustment of the state of charge.

[0039] Advantageously, the substantially equal self-discharge rates reduce the need to equalize charge states of electrochemical energy storage cells 201 of the electrochemical energy storage device 200.

[0040] Fig.Figure 3 shows a schematic representation of a third embodiment of a device 302 according to the invention. An electrochemical energy storage device 300 comprises a plurality of electrochemical energy storage cells 301. Each electrochemical energy storage cell 301 is thermally coupled to an electrical resistor 303, in this embodiment an electrically conductive film with a predetermined ohmic resistance, by means of a heat-conducting device 304. In the embodiment shown, the electrically conductive film 303 essentially completely encompasses a housing of the electrochemical energy storage cell 301, thereby advantageously ensuring particularly uniform heat distribution and heat input.

[0041] The electrical resistors 303 can be switched in parallel to the electrochemical energy storage cells by means of switch 307 in order to convert electrical energy into heat.

[0042] In the embodiment shown, the electrochemical energy storage cell 305 has a lower self-discharge rate than the other electrochemical energy storage cells 301. As a result, the electrochemical energy storage cell 305 reaches the end-of-charge voltage more quickly during a charging process with a predetermined charging current and has the highest state of charge of the electrochemical energy storage cells 301. The switch 308 is closed, causing electrical current to flow through the electrical resistor 303 and electrical energy to be converted into heat.

[0043] This heat is supplied to the electrochemical energy storage cell 305 via heat conduction devices 304, thereby subjecting it to thermal stress. This thermal stress leads to a higher self-discharge rate of the electrochemical energy storage cell 305.

[0044] As a result, the self-discharge rate of the electrochemical energy storage cell 305 approximates to a higher level of a self-discharge rate of the electrochemical energy storage cells 301.

[0045] In an embodiment not shown, the electrical resistors 303 can each be electrically connected in parallel with the electrochemical energy storage cells 301. Adjusting the state of charge of the electrochemical energy storage cell 305 leads to a higher self-discharge rate due to a higher thermal load, thereby reducing adjustment of the state of charge.

[0046] Advantageously, the substantially equal self-discharge rates reduce the need to equalize charge states of electrochemical energy storage cells 301 of the electrochemical energy storage device 300. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] KR 2013 / 0100523 A

[0006] US 2013 / 307480 A1

[0007]

Claims

[1] Device (102, 202, 302) for adjusting a self-discharge rate of at least one electrochemical energy storage cell (105, 205, 305) of a plurality of electrochemical energy storage cells (101, 201, 301) of an electrochemical energy storage device (100, 200, 300), comprising: - a plurality of electrical resistors (103, 203, 303), wherein the electrical resistors (103, 203, 303) can be electrically connected in parallel to the electrochemical energy storage cells (101, 201, 301) by means of switches (107, 207, 307) in order to convert electrical energy into heat; - a plurality of heat conduction devices (104, 204, 304) for heat transfer of the generated heat by means of heat conduction, wherein the heat conduction devices (104, 204, 304) are thermally coupled to the electrical resistors (103, 203, 303) and the electrochemical energy storage cells (101, 201, 301); whereby a higher thermal load of the at least one electrochemical energy storage cell (105, 205, 305) is achieved and the self-discharge rate of the at least one electrochemical energy storage cell (105, 205, 305) is adjusted. [2] A device (102, 202, 302) for adjusting a self-discharge rate of at least one electrochemical energy storage cell (105, 205, 305) of a plurality of electrochemical energy storage cells (101, 201, 301) of an electrochemical energy storage device (100, 200, 300) according to claim 1, wherein adjusting the self-discharge rate represents increasing the self-discharge rate to a substantially equal self-discharge rate of other electrochemical energy storage cells (101, 201, 301) of the plurality of electrochemical energy storage cells (101, 201, 301); [3] Device (102, 202, 302) for adjusting a self-discharge rate of at least one electrochemical energy storage cell (105, 205, 305) of a plurality of electrochemical energy storage cells (101, 201, 301) of an electrochemical energy storage device (100, 200, 300) according to one of the preceding claims, wherein the electrical resistors (103, 203, 303) are arranged in the immediate spatial proximity to the electrochemical energy storage cells (101, 201, 301) and / or spatially separated, preferably on a flexible printed circuit board. [4] Device (102, 202, 302) for adjusting a self-discharge rate of at least one electrochemical energy storage cell (105, 205, 305) of a plurality of electrochemical energy storage cells (101, 201, 301) of an electrochemical energy storage device (100, 200, 300) according to one of the preceding claims, wherein the electrical resistors (103, 203, 303) comprise ohmic resistors, preferably heating resistors or electrically conductive foils with a predetermined resistance. [5] Device (102, 202, 302) for adjusting a self-discharge rate of at least one electrochemical energy storage cell (105, 205, 305) of a plurality of electrochemical energy storage cells (101, 201, 301) of an electrochemical energy storage device (100, 200, 300) according to one of the preceding claims, wherein the heat-conducting devices (104, 204, 304) at least partially comprise a material with high thermal conductivity, preferably made of a metal with low electrical resistance, in particular copper or aluminum, and / or low electrical conductivity, in particular heat-conducting foils, heat-conducting paste and / or heat-conducting adhesive. [6] Method for adjusting a self-discharge rate of at least one electrochemical energy storage cell (105, 205, 305) of a plurality of electrochemical energy storage cells (101, 201, 301) of an electrochemical energy storage device (100, 200, 300), comprising the following steps: a) detecting voltage quantities which represent an electrical voltage of the electrochemical energy storage cells (101, 201, 301) at a substantially identical point in time; b) comparing the recorded voltage values; c) controlling at least one switch (107, 207, 307) as a function of the comparison in order to convert electrical energy into heat by means of at least one electrical resistor (103, 203, 303) and to actively adjust the self-discharge rate for the at least one electrochemical energy storage cell (105, 205, 305) by means of a higher thermal load. [7] Control device comprising means for carrying out a method according to claim 6. [8] Computer program comprising instructions which cause the control device according to claim 7 to carry out the method steps according to claim 6. [9] A machine-readable storage medium on which the computer program according to claim 8 is stored. [10] Use of a device (102, 202, 302) according to one of claims 1 to 5 and / or a method according to claim 6 in electrical energy storage devices (100, 200, 300) for electric vehicles, fuel cell vehicles, hybrid vehicles, plug-in hybrid vehicles, aircraft, pedelecs or e-bikes, for portable devices for telecommunications or data processing, for electrical hand tools or kitchen appliances, as well as in stationary storage devices for storing, in particular, electrical energy obtained from renewable sources.

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