Rechargeable battery deep-discharge device for the deep discharging of rechargeable batteries

Abstract

The invention relates to a rechargeable battery deep-discharge device (10) for the deep-discharging of rechargeable batteries (12) with a first rechargeable battery connection (14.1), which has a first primary rechargeable battery connection pole (16.1) and a second primary rechargeable battery connection pole (18.1) for connecting a rechargeable battery (12.1), a second rechargeable battery connection (14.2) for connecting a second rechargeable battery (12.2) and at least a third rechargeable battery connection (14.3) for connecting a third rechargeable battery (12.3), a load connection(22) for a load for dissipating an electrical output during discharging of the rechargeable batteries (12.1, 12.2, 12.3) and a discharge circuit (20), by means of which the first rechargeable battery connection (14) can be switched into a discharge switching state, in which the rechargeable battery (12.1) connected at the first rechargeable battery connection (14.1) is connected to the load connection (22), and a standby switching state, in which the rechargeable battery (12.1) connected at the first rechargeable battery connection (14.1) is not connected to the load connection (22) and the poles (16.1, 18.1) are not short-circuited, wherein the discharge circuit (20) is configured in such a way that, for each rechargeable battery connection (14.1, 14.2, 14.3) in its discharge switching state, the rechargeable battery (12.1, 12.2, 12.3) connected at the rechargeable battery connection (14.1, 14.2, 14.3) is connected in series to the rechargeable batteries (12.1, 12.2, 12.3) that are connected at the other rechargeable battery connections (14.j) in the discharge switching state, and discharge circuit (20) is configured to automatically and repeatedly switch the first rechargeable battery connection between the discharge switching state and the standby switching state such that a discharge current of the first rechargeable battery can be reduced.

Description

[0001] Accumulator deep discharge device for deep discharging of accumulators

[0002] The invention relates to a rechargeable battery deep discharge device for discharging, in particular deep discharging, rechargeable batteries, with (a) at least one rechargeable battery terminal which has a first rechargeable battery terminal pole and a second first rechargeable battery terminal pole for connecting a rechargeable battery, (b) a load terminal for a load for discharging an electrical power when discharging the rechargeable battery, (c) a discharge circuit by means of which the rechargeable battery terminal can be switched (i) into a discharge state in which the rechargeable battery connected to the rechargeable battery terminal is connected to the load terminal, and (ii) a standby state in which the rechargeable battery connected to the rechargeable battery terminal is not connected to the load terminal and the poles are not short-circuited.

[0003] DE 10 2020 118 418 or US 2023 / 0268758 A1 describe such a device which is used to discharge accumulators before recycling.

[0004] EP 4 333 158 A1 describes a method and a device for discharging individual accumulators, in which the discharge current can be limited, for example, with a controllable electronic load.

[0005] A battery deep discharge device with the highest possible productivity is desirable, meaning it can discharge as many batteries as possible per unit of time. However, it has been shown that discharging batteries too quickly can lead to thermal runaway. In a thermal runaway, part of the battery heats up so much that the separator of a galvanic cell in the battery loses its function, resulting in a rapid reaction of the components of the respective galvanic element. The resulting temperature increase leads to the destruction of other galvanic cells, with a further temperature increase. Thermal runaway is thus an uncontrolled chain reaction that usually results in the battery catching fire.

[0006] The invention is based on the object of reducing disadvantages in the prior art, in particular of improving the productivity of the accumulator deep discharge device without compromising safety.

[0007] The invention solves the problem by means of a generic accumulator deep discharge device in which the discharge circuit is designed for repeated automatic switching between discharge switching state and standby switching state so that a discharge current of the accumulator can be reduced, in particular so that the discharge current of the accumulator is permanently reduced.

[0008] An advantage of the invention is that the discharge current with which the accumulator connected to the load terminal is discharged can be reduced in a controlled manner. This is particularly advantageous when there is a risk of the accumulator overheating or when the electrical energy released during the discharge of at least one accumulator cannot be effectively dissipated.

[0009] The advantage is that in this way the battery can usually be discharged gently, so that the subsequent recycling can be carried out more easily and / or more efficiently and / or more safely.

[0010] It is particularly advantageous that, for example, the first discharge current of the first rechargeable battery can be reduced in such a way that the discharge current of another rechargeable battery connected to a different battery terminal is not dependent on the first discharge current. In particular, the discharge current of a battery terminal depends only on the properties of the rechargeable battery connected to the battery terminal. This advantage is particularly pronounced when—according to a preferred embodiment—a plurality of rechargeable batteries with different charge states and / or different battery voltages and / or different aging states are discharged simultaneously.

[0011] It is also advantageous that with the accumulator deep discharge device according to the invention, three different types of discharge, which could also be called phases of discharge, can be set, namely (i) discharging with the current that occurs when discharging the respective accumulator when the battery connection is in the discharge switching state, in particular the maximum possible current, (ii) discharging with reduced current, by switching between the discharge switching state and the standby switching state and (iii) short-circuiting.

[0012] In the context of the present description, deep discharge is understood to mean discharging to a cell voltage that corresponds at most to a final cell voltage at which the accumulator is damaged, in particular irreversibly damaged, due to the discharge. In particular, the accumulator deep discharge device is designed to discharge the accumulator to a cell voltage of at most one-fifth of the nominal voltage, in particular at most one-tenth of the nominal voltage. In other words, the final cell voltage is preferably at most one-fifth of the nominal voltage, in particular at most one-tenth of the nominal voltage. For example, the accumulator deep discharge device is designed to discharge the at least one accumulator to a final battery voltage that is at most 1 V, in particular at most 0.5 V, for example at most 0.2 V, in particular at most 0.1 V, for example 0 V.

[0013] A battery deep discharge device is understood, in particular, to be a device designed to deeply discharge a battery. In other words, there is no device for preventing the deep discharge of the batteries.

[0014] Repeated automatic switching between the discharge switching state and the standby switching state is understood in particular to mean that a rechargeable battery is switched from the discharge switching state to the standby switching state and back at least ten times, in particular at least one hundred times. In particular, the switching from the discharge switching state to the standby switching state and back occurs to reduce the discharge current.

[0015] The feature that the discharge current of the accumulator is permanently reduced is understood in particular to mean that the discharge current of the accumulator is reduced by the automatic switching between the discharge switching state and the standby switching state for at least one second, in particular at least one minute, and specifically by at least 5%, in particular at least 10%, in particular at least 15%.

[0016] The feature that the discharge circuit is designed for automatic switching between the discharge switching state and the standby switching state at the switching frequency is understood in particular to mean that the discharge circuit can be controlled such that the switching frequency can be achieved. It is possible, but not necessary, for this switching frequency to be reached or exceeded during the entire discharge process. In particular, it is sufficient if, within the scope of a method according to the invention, the switching frequency is reached or exceeded for at least 1 second, in particular at least 10 seconds, in particular at least 1 minute, particularly preferably at least 10 minutes.

[0017] The switching frequency is defined as the quotient of the number of transitions from the discharge switching state to the standby switching state or vice versa (the numerator) and the time unit within which these transitions occur (the denominator). The time unit is, for example, 1 second. Thus, 500 transitions from the charge state to the standby switching state and 500 transitions from the standby switching state to the discharge switching state per second result in a switching frequency of around 1 kHz. It is possible, but not necessary, that the time between a transition from the discharge switching state to the standby switching state or vice versa be the same. The switching frequency is preferably at least 1 Hz and / or at most 1000 Hz, in particular at most 100 Hz.

[0018] The standby switching state and a short-circuit switching state can be realized even if no battery is connected to the battery terminal. The switching state of the battery terminal refers to the state of the battery terminal, regardless of whether a battery is connected to the corresponding battery terminal or not. In the discharging switching state, the connected battery releases electrical energy, which is discharged via the load terminal.

[0019] The standby state is the state of the battery terminal in which a battery connected to the battery terminal is neither connected to the load terminal nor has short-circuited poles. The standby state can also be entered without a battery connected to the battery terminal. In the standby state, the battery does not deliver any electrical energy.

[0020] The discharge circuit preferably has a first switching element and a second switching element for each battery terminal. The first switching element is preferably a first semiconductor switch, but this is not required. When reference is made to the first semiconductor switch below, a switching element is always meant in a very general way. The second switching element is preferably a second semiconductor switch, but this is not required. When reference is made to the second semiconductor switch below, a switching element is always meant in a very general way.

[0021] The switching elements are preferably connected in such a way that the corresponding battery terminal is in the standby state when the second switching element is open.

[0022] The switching elements are preferably connected in such a way that the corresponding battery terminal is in the short-circuit state when both switching elements are closed.

[0023] The switching elements are preferably connected in such a way that the corresponding battery terminal is in the energy extraction state when the second switching element is closed and the first switching element is open.

[0024] Preferably, for each second switching element, regardless of the switching state of the first switching element, the accumulator connected to the corresponding battery terminal can only be discharged if the second switching element is closed.

[0025] An accumulator is understood, in particular, to be a galvanic cell or a battery consisting of several galvanic cells. It is possible for the individual galvanic cells to be connected to one another in a series circuit. Alternatively or additionally, at least some of the galvanic elements are connected in parallel. In particular, the accumulator deep discharge device is suitable for accumulators in which groups of series-connected galvanic elements are connected in parallel. In other words, the accumulator can be a (battery) module or a (battery) system. It is advantageous if the accumulator deep discharge device has at least two, in particular at least three, battery terminals. In this case, the discharge circuit is designed to switch the battery terminals to the discharge switching state and the standby switching state.It is possible that the battery deep discharge device has more than two terminals, wherein one or more battery terminals cannot be switched to the discharge switching state and / or the standby switching state.

[0026] The only important thing is that at least one, in particular at least two, preferably at least three, battery terminals can be switched into the discharge switching state and the standby switching state as specified.

[0027] It is advantageous if the switching frequency is a multiple of 50 Hz or 60 Hz, but this is not necessary.

[0028] Preferably, the switching occurs at a predetermined switching frequency. For example, the switching frequency is at least 1 hertz, in particular at least 10 hertz, in particular at least 100 hertz, in particular at least 1 kHz, in particular at least 10 kHz, particularly preferably at least 100 kHz. Alternatively or additionally, the discharge circuit is designed for automatic continuous switching between the discharge switching state and the standby switching state.

[0029] According to a preferred embodiment, the rechargeable battery deep discharge device has a second battery terminal for connecting a second rechargeable battery and at least one third battery terminal for connecting a third rechargeable battery. The discharge circuit is preferably designed such that, for the second and third battery terminals, in particular for each battery terminal in the discharge switching state, the rechargeable battery connected to the rechargeable battery terminal is connected in series with the rechargeable batteries connected to the other battery terminals in the discharge switching state.

[0030] It should be noted, however, that the rechargeable batteries do not have to be part of the rechargeable battery discharge device. In other words, preferably at least three rechargeable batteries can be discharged simultaneously using the rechargeable battery deep discharge device. The voltages of these rechargeable batteries add up because they are connected in series. It is advantageous if the discharge current for the second rechargeable battery terminal can be reduced independently of the first rechargeable battery terminal. In this way, the discharge current for the connected rechargeable batteries can be individually reduced and thus, in particular, optimized. It is advantageous if the discharge current for the third rechargeable battery terminal can be reduced independently of the first rechargeable battery terminal and the second rechargeable battery terminal.

[0031] It is also possible for the discharge circuit to be configured to automatically and repeatedly switch the second or third battery terminal, or—if present—additional battery terminals, between the discharge switching state and the standby switching state, so that the discharge current of the battery connected to the respective battery terminal can be reduced. The remaining battery terminals in the discharge state are automatically connected in series.

[0032] Preferably, the number of battery connections is at least 10, in particular at least 20.

[0033] According to one embodiment, the discharge circuit is designed to automatically and repeatedly switch the second battery terminal and / or the third battery terminal between the discharge switching state and the standby switching state, so that a discharge current of the second battery can be reduced independently of the discharge current of the first battery. In particular, the discharge circuit is designed to reduce the discharge currents of a plurality of the battery terminals, in particular all battery terminals, independently of the discharge current of a plurality of the other battery terminals, in particular all other battery terminals. This has the advantage that several batteries can be discharged with the discharge current most suitable for them. This, in turn, maximizes the productivity of the battery deep discharge device and minimizes the risk of battery failures during discharging.

[0034] In particular, it is possible that a second switching frequency with which the second battery terminal is switched from the discharge switching state to the standby switching state and back differs from the first switching frequency with which the first battery terminal is switched from the discharge switching state to the standby switching state and back.

[0035] According to one embodiment, the switching operations during the automatic, repeated switching between the discharge switching state and the standby switching state of two battery terminals are independent of each other. In other words, the switching of a battery terminal from the discharge switching state to the standby switching state, or vice versa, does not depend on whether another battery terminal is switched.

[0036] In particular, the battery deep discharge device is designed so that batteries connected to different battery terminals can be discharged with different discharge currents, in particular adjustable ones and / or limited to a target discharge current, when the electrical energy of the batteries is dissipated via the inverter or the DC-DC voltage converter. This applies in particular below the final discharge voltage.

[0037] Preferably, the discharge circuit is designed to automatically and continuously detect a battery terminal voltage of at least one battery terminal. Preferably, the discharge circuit is designed to automatically reduce the discharge current to a target discharge current when the battery terminal voltage is below a first predetermined voltage, in particular a final discharge voltage of the accumulator connected to the battery terminal, by repeatedly switching between the discharge switching state and the standby switching state.

[0038] The probability of a battery experiencing thermal runaway, i.e., the uncontrolled discharge of its stored electrical energy, increases significantly below the cut-off voltage. It is therefore advantageous to reduce the discharge current to mitigate this risk.

[0039] Above the end-of-discharge voltage, the probability of thermal runaway depends almost entirely on the battery voltage. It is therefore unnecessary, and according to a preferred embodiment, that above the end-of-discharge voltage, the discharge current is not limited to a target discharge current by repeatedly switching between the discharge switching state and the standby switching state, in particular not to a target discharge current that is less than 0.7 times the discharge current that would flow without limitation.

[0040] It is possible to discharge below the first predetermined voltage, in particular the final discharge voltage, using an ohmic resistor. However, it has been found that it is advantageous to discharge below the predetermined voltage and above the minimum voltage using an inverter or DC-DC voltage converter connected to the load connection. This allows more of the electrical energy stored in the battery to be used and also reduces the equipment required, since an ohmic resistor and, if applicable, devices for dissipating the resulting heat are no longer necessary. The target discharge current is understood to be an electrical current that is not exceeded during discharging by switching to the standby state sufficiently frequently and for a long time. However, it is possible that the actual discharge current is lower than the target discharge current.

[0041] According to one embodiment, a target discharge current function is stored in the battery discharge device, for example in the processor, which assigns a target discharge current to each of two or more battery voltages U12 or cell voltages. This ensures that the discharge current is always so small that the risk of thermal runaway of a battery is sufficiently small, yet discharge can still be carried out at the maximum discharge rate. The respective target discharge current is the upper limit of the discharge current that a battery can deliver before the discharge circuit limits the discharge current by switching between the discharge switching state and the standby switching state. Smaller discharge currents are always possible.

[0042] This target discharge current function preferably contains at least one target discharge current for a battery voltage above the end-of-discharge voltage. The target discharge current function preferably contains at least one (preferably 2, 3, or more) target discharge current for a battery voltage that is at most the end-of-discharge voltage. The target discharge current function can be specified, for example, by a mathematical formula. Alternatively, the target discharge current function can be stored by linking battery voltages to the respective target discharge currents.

[0043] A discharge circuit configured to automatically perform a method comprising the steps of (a) detecting a waiting state time portion, (b) switching to the waiting state, (c) remaining in the waiting state for a waiting state interval time, (d) switching from the waiting state, and (e) remaining outside the waiting state for a discharge state interval time, wherein (f) the waiting state interval time and the discharge state interval time are selected such that, averaged over a predetermined averaging time, the quotient of the waiting state interval time as the numerator and the averaging time as the denominator corresponds to the waiting state time portion. The waiting state time portion could also be referred to as the target waiting state time portion.

[0044] The detection of the waiting switching state time component can also be a detection of the (target) discharge current and / or the (target) waiting switching state time component.

[0045] Detecting the waiting switching state time portion means, in particular, that the corresponding numerical value or a code of this numerical value is read or received by a computing unit or read by an input device. An input device is a device into which an operator can enter a numerical value.

[0046] For example, an operator can use the input device to increase the waiting time (and thus reduce the discharge current) if there is concern that a smaller waiting time (and thus a higher discharge current) would lead to excessive heating of the corresponding battery. Furthermore, the operator can change the waiting time depending on the battery's contacting. For example, if a battery can only be connected using a terminal, the discharge current should not be too high. However, if the battery can be contacted over a large area, the discharge current can be selected to be high, thus keeping the waiting time low.

[0047] The waiting time is preferably recorded separately for each battery connection. This makes it possible to specify the discharge rate for each individual battery. The waiting time ranges from 0 (discharge at the maximum discharge rate) to 1 (no discharge at all).

[0048] Preferably, the discharge circuit is designed to automatically carry out a method comprising the steps of (a) detecting a battery state parameter of a rechargeable battery connected to a battery terminal and (b) discharging with a standby switching state component which depends on the battery state parameter.

[0049] The battery condition parameter is a parameter that describes the extent to which the battery has aged or the battery's current condition. The battery condition parameter can be acquired via an input device. Alternatively or additionally, the battery condition parameter can be measured by the discharge circuit.

[0050] The battery condition parameter is, for example, the internal resistance, the impedance or the conductance of the battery, the capacity of the battery relative to its nominal capacity, the number of charge and discharge cycles, the age of the battery and / or the total electrical energy charged and discharged during the lifetime of the battery.

[0051] According to a preferred embodiment, the discharge circuit is designed to measure the battery state parameter, in particular the internal resistance, the impedance, or the conductance. In particular, the discharge circuit is designed to apply a voltage with at least two, in particular several, test frequencies and to detect the impedance of the accumulator as a function of the test frequency. Preferably, the discharge circuit is designed to calculate the battery state parameter from the impedances thus measured. For this purpose, the discharge circuit preferably has a digital memory in which the dependence of the battery state parameter on the impedances at different test frequencies is stored.

[0052] According to one embodiment, the rechargeable battery deep discharge device has at least one temperature gauge for measuring the temperature of rechargeable batteries connected to a battery terminal. It is possible for the temperature gauge to measure the temperature of one, two, three, or more rechargeable batteries simultaneously.

[0053] Preferably, the discharge circuit is designed to automatically carry out a method comprising the steps of (a) detecting the battery temperature of at least one battery connected to a battery terminal and (b) discharging with a waiting switching state time portion that depends on the battery temperature. For example, the waiting switching state time portion is increased if the battery temperature exceeds a predetermined temperature threshold. As described above, thermal runaway of batteries is a risk during discharge. The higher the temperature of the battery, the higher the risk of thermal runaway. By monitoring the temperature of the at least one battery and adapting the waiting switching state time portion to its temperature, the risk of thermal runaway is minimized and / or the discharge rate is optimized.

[0054] For example, the temperature sensor is a thermocouple. It is possible that the temperature sensor is attached to a clamping device used to fix the batteries relative to the battery deep discharge device.

[0055] According to one embodiment, the temperature measuring device is a thermal camera, which can also be referred to as an IR camera, and which is positioned such that at least one, in particular at least two, and particularly preferably at least three, rechargeable batteries, each connected to a battery terminal, are within the field of view of the thermal camera. Thermal cameras have the advantage of being able to measure with spatial resolution. Therefore, if a galvanic element in a spatially large rechargeable battery becomes too hot, this can be detected by a thermal camera, whereas a thermal sensor arranged at a distance would not detect this heating or would only detect it very late.

[0056] Alternatively or additionally, the temperature sensor comprises at least one contact temperature sensor for thermally contacting at least one accumulator connected to a battery terminal. Such a contact temperature sensor may, for example, be a thermocouple.

[0057] Preferably, the discharge circuit is designed to automatically reduce the discharge current of a rechargeable battery connected to a battery terminal and for which the temperature sensor detects a rechargeable battery temperature that is above an alarm temperature and / or above an alarm temperature change rate. In particular, the discharge current is reduced to zero.

[0058] In other words, the discharge circuit for each battery terminal uses the temperature sensor to measure the battery temperature of a battery connected to the respective battery terminal and compares it with the specified alarm temperature. Alternatively or additionally, a temperature change rate is calculated from two or more temperature measurements. If the alarm temperature and / or the alarm temperature change rate is exceeded, the risk of thermal runaway is so great that battery discharge is reduced by reducing the discharge current through repeated switching between the discharge switching state and the standby switching state, in particular by interrupting the discharge by switching the battery terminal to the standby switching state. The battery connected to the battery terminal then no longer emits electrical energy.

[0059] Preferably, each battery terminal is assigned a voltmeter. This allows the discharge level of the connected battery to be measured at any time.

[0060] Preferably, the discharge circuit is designed such that each battery terminal can be switched to a short-circuit state in which the two poles are short-circuited. If the battery voltage is sufficiently low, the energy content remaining in the battery is so small that extracting the remaining electrical energy is no longer economically viable. In order to fully discharge the battery, particularly to protect operating personnel, it is advantageous to short-circuit the poles of the battery. This means, in particular, that the ohmic resistance of the connection between the poles of the battery is less than 5 ohms, in particular less than 1 ohm. In the short-circuited state, an electrical current flows, but hardly any electrical power, since the battery voltage is low.

[0061] Preferably, the discharge circuit is configured to automatically perform a method comprising the steps of (i) detecting the battery voltages for each battery terminal to which a rechargeable battery is connected, and (ii) switching the battery terminal to the short-circuit state if the battery voltage or a cell voltage of galvanic cells of the rechargeable battery does not exceed a predetermined minimum voltage. In this way, a rechargeable battery is quickly and completely discharged. Preferably, the discharge circuit is configured such that a battery terminal is not switched to the short-circuit state if the battery voltage is above the minimum voltage.

[0062] The cell voltage is calculated as the quotient of the battery voltage as the numerator and the number of series-connected galvanic cells in the battery as the denominator. The number of series-connected galvanic cells is read, for example, from an input device. The input device is designed to capture an input from an operator, who can enter the number of series-connected galvanic cells for each battery terminal. This number is the number of series-connected galvanic cells for the battery connected to the battery terminal. The voltmeter is part of the battery deep discharge device.

[0063] The minimum voltage is preferably selected such that a short-circuit current in the short-circuit switching state corresponds to the discharge current delivered by the accumulator connected to the battery terminal immediately before switching to the short-circuit state. The feature that the short-circuit current corresponds to the discharge current is understood in particular to mean that the two currents can be equal; however, a deviation of, for example, a factor of 2, preferably a factor of 1.5, is possible.

[0064] The rechargeable battery deep discharge device preferably has an ammeter configured to measure the current for each battery terminal. It is possible for the rechargeable battery deep discharge device to have an ammeter for each battery terminal. However, it is also possible for at least one ammeter to be connected to measure the current at two or more battery terminals.

[0065] Preferably, the minimum voltage, when referring to the cell voltage, is lower than the end-of-discharge voltage, especially so low that reaching the minimum voltage causes irreversible damage to the battery. Discharging to a battery voltage lower than the end-of-discharge voltage is considered deep discharge.

[0066] The end-of-discharge voltage is the voltage below which the nominal capacity is 0%. The end-of-discharge voltage is specified by the manufacturer and is known for each rechargeable battery. The minimum voltage, when it relates to the cell voltage, is preferably at most 2.5 V, in particular at most 1.5 V, in particular at most 1 V, in particular at most 0.5 V, in particular at most 0.2 V, for example at most 0.1 V, in particular at most -0.1 V. The enable short-circuit current is preferably less than 120 A, in particular less than 70 A and / or greater than 1 A, in particular greater than 5 A. According to one embodiment, the discharge circuit is designed to automatically output an enable message, in particular by means of a status display, when at least one rechargeable battery terminal is in the short-circuit switching state and / or a short-circuit current corresponds at most to a predetermined enable short-circuit current.When the accumulator is sufficiently discharged, it can be de-contacted and removed from the accumulator deep discharge device, allowing a new accumulator to be discharged to be connected to the corresponding battery terminal. To trigger these sequences, the release message is advantageous. The release message can be a human-perceptible message, in particular acoustic, optical, or other, for example, haptic, and encode the fact that the corresponding accumulator can be removed from its battery terminal. However, the release message can also be, in particular exclusively, machine-readable and can be, for example, a wired or wireless, electrical or optical signal.

[0067] Preferably, the release message is only issued if the temperature of the corresponding accumulator is below a specified release temperature.

[0068] Preferably, the discharge circuit has a processor, which may preferably have a digital memory.

[0069] According to one embodiment, the discharge circuit is designed to automatically carry out a method comprising the steps of (i) detecting whether a rechargeable battery is connected to a rechargeable battery terminal and (ii) if negative, suppressing the switching of the rechargeable battery terminal to the discharge switching state or switching the rechargeable battery terminal to the standby switching state. If positive, the suppression of the switching of the rechargeable battery terminal to the discharge switching state is not suppressed. In other words, the discharge circuit, in particular the processor, detects whether a rechargeable battery is connected, for example by detecting whether a plug is inserted into the rechargeable battery terminal or by measuring the electrical resistance between the connection poles of the rechargeable battery terminal. If this is not the case, the rechargeable battery terminal is not switched to the discharge switching state, even if it would be switched to the discharge switching state if a rechargeable battery were connected.In this way, a rechargeable battery can be safely connected to the battery terminal. The rechargeable battery deep discharge device preferably has at least one reverse polarity protection circuit, in particular one for each battery terminal, by means of which the battery voltage of a rechargeable battery connected with the wrong polarity to the corresponding battery terminal is reversed, in particular automatically. A rechargeable battery is considered to be connected with the wrong polarity if it is connected with a polarity opposite to the correct polarity. Instead of "incorrect polarity," it could also be referred to as "reverse polarity."

[0070] The rechargeable battery deep discharge device preferably comprises at least one signature voltage source, wherein the signature voltage source is connected to the first rechargeable battery terminal for applying a signature voltage between the first primary battery terminal pole and the second primary battery terminal pole. The signature voltage source is preferably designed such that the signature voltage is present between the primary battery terminal poles when no rechargeable battery is connected to the first rechargeable battery terminal. The signature voltage source is preferably designed such that a voltage different from the signature voltage is present between the primary battery terminal poles when a rechargeable battery is connected to the first rechargeable battery terminal. The signature voltage differs from the rechargeable battery voltage, in particular when no rechargeable battery is connected to the primary battery terminal poles.According to one embodiment, the discharge circuit is designed to automatically carry out a method comprising the steps of (i) detecting the voltage between the first battery terminal poles and (ii) if the voltage corresponds to the signature voltage, switching the first battery terminal into the standby state or suppressing the switching of the first battery terminal from the standby state.

[0071] According to the invention, a battery deep discharge device for deep discharging batteries is also provided, with

[0072] (a) a first battery terminal having a first primary battery terminal and a second primary battery terminal for connecting a battery,

[0073] (b) a second battery terminal for connecting a second battery and

[0074] (c) at least one third battery terminal for connecting a third battery,

[0075] (d) a load terminal for a load for discharging an electrical power when discharging the accumulator and (e) a discharge circuit by means of which the first accumulator terminal (i) can be switched into a discharge switching state in which the accumulator connected to the first accumulator terminal is connected to the load terminal, and (ii) a standby switching state in which the accumulator connected to the accumulator terminal is not connected to the load terminal and the poles are not short-circuited, and

[0076] (f) at least one signature voltage source connected to the first battery terminal for applying a signature voltage between the first primary battery terminal pole and the second primary battery terminal pole.

[0077] The signature voltage source is preferably configured such that the signature voltage is present between the first battery terminal poles when no battery is connected to the first battery terminal. The signature voltage source is preferably configured such that a voltage different from the signature voltage is present between the first battery terminal poles when a battery is connected to the first battery terminal. The signature voltage differs from the battery voltage, particularly when no battery is connected to the first battery terminal poles.According to one embodiment, the discharge circuit is designed to automatically carry out a method comprising the steps of (i) detecting the voltage between the first battery terminal poles and (ii) if the voltage corresponds to the signature voltage, switching the first battery terminal into the standby state or suppressing the switching of the first battery terminal from the standby state.

[0078] Preferably, the voltmeter is arranged to measure the voltage between the primary battery connection poles.

[0079] The advantage of this is that it is easy to detect whether or not a rechargeable battery is connected to the first battery connection. If it is detected that no rechargeable battery is connected, the first battery connection is switched to the standby state or held there. In the standby state, the first battery connection poles are not connected to the load connection and are not short-circuited. If a rechargeable battery is now connected to the first battery connection, the rechargeable battery cannot short-circuit, which would be the case if the battery connection were in the short-circuit state. In addition, a voltage can be present at the battery connection, which would be the case if the battery connection were in the discharge state. The feature that the signature voltage is applied between the first battery connection poles is understood in particular to mean that the signature voltage is applied in such a way that it is measured using the voltmeter, which is preferably present.If the battery deep discharge device has a reverse polarity protection circuit, the signature voltage source is preferably arranged so that the signature voltage is not reversed when the battery voltage is reversed by means of the reverse polarity protection circuit.

[0080] The feature that a voltage different from the signature voltage is present between the terminals of the first battery connection when a battery is connected to the first battery connection is understood in particular to mean that the signature voltage and the battery voltage have a detectably different magnitude and / or a detectably different frequency and / or a detectably different polarity. Since the battery voltage is always a direct voltage, any signature voltage that is an alternating voltage is different from the battery voltage.

[0081] Suppressing the switching of the first battery terminal from the standby state means that the first battery terminal is not switched from the standby state, even if this would be required by another rule. If the measured voltage no longer corresponds to the signature voltage, the switching of the first battery terminal from the standby state is no longer suppressed.

[0082] The voltage between the terminals of the primary battery connection is preferably measured regularly. This means, in particular, that the voltage is measured so frequently that the time between two measurements is so short that a discharged battery is not removed from the primary battery connection and a charged battery is not connected to the primary battery connection. Preferably, the voltage is measured at least once per minute, at least once every 10 seconds, at least once every 3 seconds, and preferably at least once per second.

[0083] According to one embodiment, the discharge circuit is designed to automatically carry out a method comprising the step: if the first battery terminal is in the short-circuit switching state, regularly switching the battery terminal briefly from the short-circuit switching state, in particular into the standby switching state.

[0084] A short-term switching operation is understood to mean, for example, a switching operation lasting a maximum of 5 seconds, in particular a maximum of 1 second. The shorter the switching time, the more favorable it is as a rule. For example, a switching time of 5 milliseconds can be advantageous. Preferably, the short-term switching operation

[0085] Regular switching is understood, in particular, to mean switching at least once per minute, at least once every 10 seconds, and especially at least once every 3 seconds. Preferably, regular switching occurs at a frequency that corresponds to the frequency when detecting the voltage between the primary battery terminal poles, since signature voltage can be detected / checked when the battery terminal is not in a short-circuit state.

[0086] If the battery terminal is in a short-circuit state, the following applies: If no battery is connected, the signature voltages are measured during a brief switch to the standby state, and switching the battery terminal from the standby state is suppressed, thus keeping the battery terminal in the standby state. If a battery is connected, a voltage different from the signature voltage is measured, for example, due to the high internal resistance of the signature voltage source, and the system switches back to the short-circuit state. This makes it possible to detect whether a discharged and therefore short-circuited battery has been removed from the battery terminal.

[0087] If the battery connector is in the energy extraction state, a battery is always connected to the battery connector. The battery voltage is measured, which does not correspond to the signature voltage.

[0088] If the battery connection is in the standby state, the following applies: If no battery is connected, the signature voltage is measured and the standby state is maintained. If a battery is connected, the measured voltage is the signature voltage, not the signature voltage, for example, due to a sufficiently high internal resistance of the signature voltage source. The standby state is not maintained, and the battery connection can be switched to the energy extraction state, for example. The signature voltage source is preferably an AC voltage source. Batteries always emit a DC voltage, so an AC voltage is particularly easy to identify as a signature voltage source.

[0089] According to one embodiment, the signature voltage source outputs a signature voltage that has a different polarity than a battery or a reverse polarity circuit terminal of a reverse polarity protection circuit. Alternatively or additionally, the signature voltage is greater than the battery voltage.

[0090] It is advantageous if the signature voltage source has an internal resistance selected so that the voltage between the primary battery terminals decreases in magnitude when a battery is connected to the primary battery terminals. For example, the internal resistance is at least 100 kiloohms, in particular at least 1 megaohm.

[0091] But it is also possible if the internal resistance is less than 100 kiloohms.

[0092] The switching state can then also be detected. However, the signature voltage source then delivers a high electrical current, which reduces the efficiency of the battery deep discharge device.

[0093] According to one embodiment, the rechargeable battery deep discharge device comprises a battery handling device configured to automatically disconnect a rechargeable battery from the battery terminal to which it is connected, particularly when a release message is present for the rechargeable battery or the battery terminal. The battery handling device is, for example, a robot.

[0094] Preferably, the battery handling device is designed to move the battery away from the battery terminal to which it was previously connected. For example, the battery is transported to a warehouse or recycling facility.

[0095] Preferably, the battery handling device is designed to automatically move a rechargeable battery to be discharged to an unoccupied battery port. Rechargeable batteries can be quite heavy, so it is advantageous if the battery is transported automatically. Preferably, the battery handling device is designed to connect the rechargeable battery to the battery port or, alternatively, to output a connection request message that encodes that this rechargeable battery must be connected to the battery port, particularly by an operator.

[0096] According to one embodiment, the accumulator deep discharge device comprises an ammeter for detecting the electrical current flowing through the series circuit. This ammeter is present alternatively or in addition to the at least one ammeter for measuring the current flowing through at least one battery terminal.

[0097] The discharge circuit is preferably designed to automatically detect a target discharge current for at least one battery terminal, in particular for a plurality of battery terminals, in particular for all battery terminals. This is done, for example, by determining the battery condition parameter, in particular the battery temperature, and by reading a database in which a target discharge current is assigned to each battery condition parameter. Alternatively, the target discharge current is detected via an input device into which a user enters the corresponding target discharge current and / or the battery condition parameter.

[0098] It is advantageous if the discharge circuit is designed to switch between the discharge switching state and the standby switching state with a switching frequency selected such that a time-averaged actual discharge current corresponds to the target discharge current. The averaged actual discharge current is averaged over a predetermined averaging time. This is generally freely selectable, but is preferably at least 1 second and / or at most 10 minutes. In this way, the accumulator is discharged with the optimal discharge current for it.

[0099] Preferably, the accumulator deep discharge device has the above-mentioned input device for entering the desired discharge current and / or the battery state parameter for at least one accumulator connection, in particular for at least one group of accumulator connections.

[0100] For rapid switching, the discharge circuit preferably has a semiconductor switch, in particular a bipolar transistor with an insulated gate electrode and / or a MOSFET, for switching into the discharge switching state or the standby switching state.

[0101] Preferably, the discharge circuit is designed to automatically carry out a method comprising the steps of (a) detecting a target power output of the accumulator deep discharge device and (b) if an actual power output is greater than the target power output, increasing the standby switching state time portion for at least one battery terminal. One advantage of the accumulator deep discharge device is that it makes useful use of the electrical energy stored in the accumulators to be discharged. If stored energy cannot be used, the power output of the accumulator discharge device can be throttled by increasing the standby switching state time portion of at least one battery terminal.

[0102] Preferably, the battery deep discharge device has an inverter for supplying alternating current at a specified frequency and voltage and / or a DC-DC voltage converter for supplying a DC voltage at a specified voltage. The inverter or DC-DC voltage converter is connected to the load terminal. In this way, the electrical energy from the batteries can be effectively utilized.

[0103] According to a preferred embodiment, the inverter has a chopper frequency at which the alternating current is generated from the direct current from the batteries. It is advantageous if the switching frequency for switching between the discharge switching state and the standby switching state is higher than the chopper frequency, preferably by at least a factor of 2. Thus, reducing the discharge current does not affect the inverter.

[0104] According to the invention, there is also a method for discharging, in particular deep discharging, rechargeable batteries, comprising the steps of (i) connecting a rechargeable battery to a rechargeable battery terminal of a rechargeable battery discharging device according to one of the preceding claims and (ii) discharging the rechargeable battery and interrupting the discharge of the rechargeable battery, wherein alternating between discharging and non-discharging is carried out at least temporarily with a switching frequency of at least 1 kilohertz. The discharge circuit can thus preferably switch the rechargeable battery terminals either to the discharge switching state or the standby switching state. In the standby switching state, the connected rechargeable battery does not emit any electrical energy. In the discharge switching state, the connected rechargeable battery emits electrical energy.

[0105] The discharge switching state is either the short-circuit switching state, in which the battery terminals are short-circuited, or an energy extraction state, in which the battery delivers electrical energy to the load terminal. The discharge circuit can preferably switch the battery terminals to all three switching states (short-circuit switching state, energy extraction state, standby switching state).

[0106] The process is preferably part of a recycling process for rechargeable batteries. The aim of the process is, in particular, to at least largely minimize the energy content of the rechargeable battery. This facilitates the subsequent recycling steps.

[0107] Preferably, the method comprises the following step: continuously detecting a battery terminal voltage that drops across the respective battery terminal for at least a plurality of the battery terminals of the battery discharge device.

[0108] If the battery terminal voltage is below a first predetermined voltage, in particular a final discharge voltage at the respective battery terminal, the discharge current is preferably reduced to a target discharge current. This reduces the likelihood of thermal self-destruction of a battery. Furthermore, the energy contained in the battery is utilized even below the first predetermined voltage, preferably by means of the inverter and / or the DC-DC voltage converter.

[0109] If the battery terminal voltage Ui4j is below a specified minimum voltage Umin,i2.j, which is lower than the final discharge voltage (UES), short-circuit the respective battery terminal. In other words, it is advantageous if the battery is only short-circuited when virtually all of its electrical energy has been drawn and / or the remaining energy is so low that a sudden release of the remaining energy no longer poses any danger, such as burning, melting cables, or arcing.

[0110] Preferably, the method comprises the step of inverting the connection voltage applied to the load connection of the accumulator discharge device to an alternating voltage with a predetermined frequency and voltage and / or voltage converting the connection voltage to a direct voltage.

[0111] The invention also solves the problem by a method for deep discharging rechargeable batteries, in particular within the framework of a recycling process, comprising the following steps: (a) connecting at least one rechargeable battery to a first rechargeable battery terminal and a second first rechargeable battery terminal of a first rechargeable battery terminal of a rechargeable battery deep discharge device, (b) applying a signature voltage between the first rechargeable battery terminal and the second first rechargeable battery terminal by means of a signature voltage source, which is designed such that (i) the signature voltage is applied between the first rechargeable battery terminal poles when no rechargeable battery is connected to the first rechargeable battery terminal, and (ii) a voltage different from the signature voltage is applied between the first rechargeable battery terminal poles when a rechargeable battery is connected to the first rechargeable battery terminal, wherein the signature voltage differs from the rechargeable battery voltage,(c) detecting the voltage between the first battery terminal poles and (d) if the voltage corresponds to the signature voltage, switching the first battery terminal into the standby state or suppressing the switching of the first battery terminal from the standby state.

[0112] Preferred embodiments of this method include steps described above as steps that the discharge circuit can perform.

[0113] The invention is explained in more detail below with reference to the accompanying drawings.

[0114] Figure 1 is a schematic circuit diagram of a battery deep discharge device according to the invention,

[0115] Figure 2 shows the accumulator deep discharge device according to Figure 1, in which two accumulator terminals are in the discharge switching state, one accumulator terminal is in the standby switching state and one accumulator terminal is in the short-circuit switching state and

[0116] Figure 3 is a schematic circuit diagram of a rechargeable battery deep discharge device according to the invention in accordance with a second embodiment.

[0117] Figure 1 shows an inventive rechargeable battery deep discharge device 10 for discharging rechargeable batteries 12.i (i = 1, 2,...), with a first rechargeable battery connection 14.1. In Figure 1, several rechargeable battery connections 14.j (j = 1, 2, ... J; here J = 4) are shown, although only one rechargeable battery connection 14.1 is necessary. The first rechargeable battery connection 14.1 has a first pole 16.1, which is called the first primary rechargeable battery connection pole, and a second pole 18.1, which is called the second primary rechargeable battery connection pole. Correspondingly, the second rechargeable battery connection 14.2 has a first pole 16.2, which is called the first secondary rechargeable battery connection pole, and a second pole 18.2, which is called the second secondary rechargeable battery connection pole. The first rechargeable battery 12.1 is connected to the first rechargeable battery connection 14.1.

[0118] The battery deep discharge device 10 has a discharge circuit 20 having a load terminal 22. The discharge circuit 20 can have a connecting switching element 24.1, for example in the form of a first semiconductor switch, a short-circuit switching element 26.1, for example in the form of a second semiconductor switch, a voltmeter 28.1, and / or an ammeter 30.1 for the first battery terminal 14.1.

[0119] It is possible for the voltmeter 28.1 to be wired in such a way that it can successively measure the voltage present at one or more additional battery terminals 14.2, 14.3, ..., provided the accumulator deep discharge device 10 has them, which is possible but not necessary. For the sake of simplicity, a corresponding voltmeter 28.i is shown in Figure 1 for each battery terminal 14.j. It is also possible for the optional ammeter 30.1 to be wired in such a way that it can successively measure the current flowing through one or more additional battery terminals 14.2, 14.3, ..., provided the accumulator deep discharge device 10 has them.

[0120] Figure 1 shows that the accumulator deep discharge device 10 can, but need not, have a reverse polarity protection circuit 32.j for each battery terminal 14.j. If the respective accumulator 12.i is connected with the wrong polarity to its battery terminal 14.j, this is detected by the voltmeter 28.j, and the reverse polarity protection circuit 32.j changes the polarity. As a result, the battery voltage with the correct polarity is always present at a reverse polarity circuit terminal 33.j of the reverse polarity protection circuit 32.j. After reversing the battery voltage, the battery voltage with the reversed polarity is present at the reverse polarity circuit terminal 33.j.

[0121] The accumulator deep discharge device 10 can have a processor 34, which is connected to the switching elements, in particular in the form of the semiconductor switches 24.j, 26.j, and can control them to close and / or open. In particular, the processor controls the switching elements such that for each accumulator 12.i, the respective discharge current Ii2.i does not exceed a possibly predetermined target discharge current Ii2.i,soii. The target discharge current Ii2.i,soii can be individually defined for each battery terminal 14.i, so that at least two target discharge currents Ii2.i,soii, Ii2.j,soii (i + j) can differ from one another. The processor 34 is connected to all voltmeters 28.j and reverse polarity protection circuits 32.j.

[0122] The processor may also be connected to an input device 36 via which a user 38 can enter data, for example a target discharge current Isoiij or a battery state parameter Pj for each at least one battery terminal 12.j.

[0123] A fuse 25.j can be arranged between the first semiconductor switch 24.j and the associated battery terminal 14.j.

[0124] Figure 2 schematically shows the state in which the connecting switching element 24.1, in the form of the first semiconductor switch, is closed, whereas the short-circuiting switching element 26.1, in the form of the second semiconductor switch, is open. In this case, the accumulator 12.1 is connected to the load terminal 22. If electrical power is drawn at the load terminal 22, the accumulator 12.1 contributes to this power. The accumulator terminal 14.1 is thus in the energy draw state.

[0125] The first semiconductor switch 24.2 of the second battery terminal 14.2 is also closed, and the second semiconductor switch 26.2 of the second battery terminal 14.2 is also open. This connects the batteries 12.1 and 12.2 in series. The first semiconductor switch 24.3 of the third battery terminal 12.3 is open, and the second semiconductor switch 26.3 of the third battery terminal 12.3 is closed. The third battery terminal 12.3 is thus in the standby state.

[0126] The first semiconductor switch 24.4 of the fourth battery terminal 12.4 and the second semiconductor switch 26.4 of the fourth battery terminal 12.4 are closed. The battery 12.4 is thus short-circuited. The fourth battery terminal 12.4 is thus in the short-circuit state.

[0127] Depending on the battery voltage U12.1 applied to the terminals of battery 12.1 and the power drawn at load terminal 22, a discharge current I12.1 is produced by battery 12.1. This discharge current corresponds to a total discharge current Iges flowing through the entire series circuit. A total ammeter 40 may be present to measure this total discharge current Iges. The battery voltage U12.1 corresponds to the battery terminal voltage Ui4..j of the battery terminal 14.j to which battery 12.i is connected.

[0128] If the discharge current delivered by the rechargeable battery 12.1 is greater than the target discharge current Isoii,i2.i , which was detected, for example, by the input device 36, the processor 34 can control the switching elements 24.1, 26.1 in the form of semiconductor switches so that they switch back and forth between the discharge switching state and the standby switching state. The changes between the discharge switching state and the standby switching state correspond to a switching frequency f. The greater the proportion of time in which the rechargeable battery connection 14.1 is in the discharge switching state, the greater the average discharge current l. The average discharge current is, for example, averaged over an averaging time T of, for example, T = 1 second. In other words, the switching elements 24.1, 26.1 in the form of semiconductor switches are pulse width controlled.

[0129] In order to minimize voltage and current fluctuations caused by switching back and forth, the switching frequency can be f = 1 kHz or more.

[0130] Switching frequencies of at most 1 kHz, in particular at most 100 Hz, are preferred. Alternatively, the switching frequency f can be 1 kHz or more, for example above 100 kHz, in particular above 1 MHz.

[0131] Figure 1 shows that the accumulator deep discharge device 10 can have a temperature sensor 42, for example in the form of a thermal camera. The accumulators 12.j are located in the field of view G of the thermal camera. The temperature sensor 42 records the temperatures Ti2j of the accumulators connected to the respective accumulator terminal 14.j and transmits them to the discharge circuit 20, in particular to the processor 34. If one of the temperatures Ti2 exceeds a predetermined alarm temperature TAiarm, the discharge circuit 20 reduces the waiting switching state time component Aw for the accumulator terminal 14.j to which the accumulator 12.j whose temperature is too high is connected. As a result, the discharge current Ii2j of the accumulator 12.j decreases, and the temperature drops.

[0132] It is also possible that the temperatures Ti2 are measured continuously and, based on a digitally stored table, the suitable target discharge current Ii2.j,soii is determined and set by the discharge circuit 20.

[0133] It is also possible for the operator 38 to enter the respective battery status parameter Pj for the accumulator connected to the battery terminal 14.j via the input device 36.

[0134] Figure 1 shows that an inverter 43 can be connected to load terminal 22. A connection voltage U22, which is a direct current, is present at load terminal 22. Inverter 43 converts the connection voltage U22 into a grid voltage with a predetermined grid voltage U44 and a predetermined grid frequency f44. This inverter can, for example, be connected to a public power grid 44. Alternatively or additionally, the load terminal can be connected to a DC-to-DC voltage converter 46, which supplies a battery buffer 48 or a DC voltage consumer with electrical energy.

[0135] If a voltmeter 28.j detects that the battery voltage U12 of one of the accumulators 12.j has fallen below a minimum voltage Umin, which corresponds, for example, to a cell voltage of 0.2 V, the corresponding accumulator 12.j is short-circuited. If the resulting short-circuit current IKS,I2J falls below a predetermined enable short-circuit current IKS.FG,SO, the processor 34, for example, issues a release message that can be perceived visually or acoustically. Alternatively, the release message is machine-readable, and an optional robot 50 disconnects the accumulator 12.j from the accumulator deep discharge device 10 upon receiving the release message.

[0136] The processor 34 is connected to at least one voltmeter 28.j and continuously records the voltage U28.j measured by the voltmeter 28.j. The voltage U28.j is the battery terminal voltage Ui4 of the battery terminal 14.j and the battery voltage Ui2.i of the battery 12.i, which is connected to the battery terminal 14.j.

[0137] If the measured voltage U28.1, i.e. the battery connection voltage Ui4 of a battery connection 14.j, falls below a first predetermined voltage UES, in particular a final discharge voltage UES, the processor 34 controls the switching elements 24.j, 26.j such that the discharge current I12J of the battery 12.I, which is connected to the battery connection 14.j, is reduced to a predetermined target discharge current Isoii,i2.i.

[0138] In the accumulator discharge device, for example in the processor, a target discharge current function can be stored which assigns to two or more battery voltages U12 or cell voltages, in particular those above and / or below the final discharge voltage, respective reduced target discharge currents lsoii,i2.i(Ui2.i).

[0139] If the measured voltage U28.1 falls below a predetermined minimum voltage Umin 12.1 , which was entered, for example, by the user 38 using the input device 36, the processor 34 controls the switching elements 24.j, 26.j such that the battery terminal 14.j is switched to the short-circuit state. The battery 12.j can then be safely de-contacted and removed.

[0140] Figure 1 shows that the rechargeable battery deep discharge device 10, in particular the discharge circuit 20, can have a first signature voltage source 52.1. The signature voltage source 52.1 is connected between the first primary battery connection terminal 16.1 and the second primary battery connection terminal 16.2 to apply a signature voltage Us. In the present case, the signature voltage source 52.1 is connected to the reverse polarity protection circuit terminal 33.1 to apply the signature voltage Us. The signature voltage source 52.1 can have an internal resistance R52.1 selected to be large enough that the voltage U28.1 measured by the voltmeter 28.1 between the primary battery connection terminals 16.1, 18.1 drops significantly when the rechargeable battery 12.1 is connected to the first battery connection 14.1. For example, the internal resistance is at least R52.1 = 100 kiloohms, in particular at least 1 megaohm. Signature voltage source 52.1 can have an internal resistance element 54.1 for this purpose.

[0141] It is advantageous if at least two battery terminals, in particular at least three battery terminals, preferably a majority of the battery terminals, in particular all battery terminals, are assigned a signature voltage source 52.j. The feature that a signature voltage source is assigned to a battery terminal is understood in particular to mean that for each battery terminal there is a signature voltage source that is connected to this battery terminal to apply the signature voltage. It is possible for a signature voltage source to be designed to be connected, in particular successively, to several battery terminals. Alternatively, a battery terminal can be connected to a signature voltage source that applies the signature voltage exclusively to this battery terminal.

[0142] The discharge circuit 20, in particular the processor 34, is connected to the at least one voltmeter 28.j and detects the voltage U28J between the respective poles 16.j, 18.j of the respective battery terminal 14.j. If the voltage U28J corresponds to the signature voltage Us, it can be ruled out that a battery is connected to the battery terminal 14.j. The processor 34 then controls the switching elements 24.j, 26.j such that the battery terminal 14.j is switched to the standby state. This ensures that the battery terminal 14.j is not short-circuited, so that connecting a charged battery could lead to an arc. The fact that the corresponding battery terminal 14.j is in the standby state can be indicated by a status indicator 56.j.

[0143] If a battery terminal 14.j is in the short-circuit state, the voltage U28 is lower than the signature voltage Us, since the voltage of the signature voltage source 52.j drops almost entirely across the internal resistance element 54.j. Therefore, the voltage U28J cannot be used to determine whether a rechargeable battery 12.j is connected to the battery terminal 12.j or not. Therefore, the discharge circuit 20, in particular the processor 34, can be configured to regularly and briefly switch the battery terminal 14.j from the short-circuit state to the standby state. If no rechargeable battery 12.j is connected, the voltage U28 rises to the signature voltage Us, and the battery terminal 12.j is maintained in the standby state.

[0144] Figure 3 shows an alternative embodiment of a rechargeable battery deep discharge device according to the invention, in which the connection switching elements 24.j and the short-circuit switching elements 26.j are designed as relays or other mechanical switching elements.

[0145] List of reference symbols

[0146] 10 Accumulator deep discharge device 44 Power grid 46 DC-DC

[0147] 12 accumulator voltage converter

[0148] 14 Battery connector 48 Battery buffer

[0149] 16 first pole

[0150] 16.1 first battery connection pole 50 robot

[0151] 18 second pole 52 signature voltage source

[0152] 18.1 second primary battery connection pole 54 internal resistance element

[0153] 56 Status display

[0154] 20 Discharge circuit

[0155] 22 Load connection T averaging time

[0156] 24 Switching element, first f switching frequency

[0157] Semiconductor switch G field of view

[0158] 25 Fuse i Running index (accumulator)

[0159] 26 Short-circuit switching element, twoI discharge current ter semiconductor switch Isoii target discharge current

[0160] 28 Voltmeter IKS short-circuit current j running index (battery connection)

[0161] 30 ammeter J Number of battery terminals

[0162] 32 Reverse polarity protection circuit Pj Battery status parameters

[0163] 33 Reverse polarity circuit connection Ui2.i battery voltage

[0164] 34 Processor Ui4.j Battery Connector Voltage

[0165] 36 Input device Umin,i2.j Minimum voltage

[0166] 38 User U22 Connection voltage

[0167] UES first specified voltage,

[0168] 40 Total ammeter discharge voltage

[0169] 42 Temperature meter Us signature voltage

[0170] 43 inverters

Claims

Patent claims 1. Accumulator deep discharge device (10) for deep discharging accumulators (12), with (a) a first battery connection (14.1) having a first primary battery connection terminal (16.1) and a second primary battery connection terminal (18.1) for connecting a battery (12.1), (b) a second battery connection (14.2) for connecting a second battery (12.2) and (c) at least one third battery terminal (14.3) for connecting a third battery (12.3), (d) a load connection (22) for a load for discharging an electrical power when discharging the accumulators (12.1, 12.2, 12.3) and (e) a discharge circuit (20) by means of which the first battery terminal (14.1) (i) into a discharge switching state in which the accumulator (12.1) connected to the first accumulator terminal (14.1) is connected to the load terminal (22), and (ii) a standby switching state in which the accumulator (12.1) connected to the accumulator connection (14.1) is not connected to the load connection (22) and the poles (16.1, 18.1) are not short-circuited, is switchable, characterized in that (f) the discharge circuit (20) is designed such that for each battery terminal (14.1, 14.2, 14.3) in its discharge switching state, the accumulator (12.1, 12.2, 12.3) connected to the battery terminal (14.1, 14.2, 14.3) is in a series circuit with the accumulators (12.1, 12.2, 12.3) which are connected to the other battery terminals (14.j) in the discharge switching state and (g) the discharge circuit (20) is designed to automatically and repeatedly switch the first battery terminal between the discharge switching state and the standby switching state, so that a discharge current of the first battery can be reduced.

2. Accumulator deep discharge device (10) according to claim 1, characterized in that the discharge circuit (20) is designed for automatically repeatedly switching the second accumulator terminal and / or the third accumulator terminal between discharge switching state and standby switching state, so that a discharge current (I12.2) of the second accumulator can be reduced independently of the discharge current (I12.1) of the first accumulator.

3. Accumulator deep discharge device (10) according to one of the preceding claims, characterized by an inverter for outputting alternating voltage of a predetermined frequency and voltage and / or a direct current-to-direct current voltage converter for outputting a direct current of a predetermined voltage, which is connected to the load terminal.

4. Accumulator deep discharge device (10) according to one of the preceding claims, characterized in that the discharge circuit (20) is designed to automatically carry out a method with the steps (i) continuously detecting a battery terminal voltage (Ui4 ) of at least one battery terminal (14.j), (ii) if the battery terminal voltage (Ui4 ) is below a first predetermined voltage (UES ), in particular a discharge end voltage, reducing the discharge current to a target discharge current (I so ii,i2.i) by repeatedly switching between discharge switching state and standby switching state, (iii) where for a battery terminal voltage (Ui4 ) above the first predetermined voltage, the discharge current is not reduced by repeated Switching between discharge switching state and standby switching state is reduced.

5. Accumulator deep discharge device (10) according to one of the preceding claims, characterized in that the discharge circuit (20) is designed to automatically carry out a method with the steps (a) Detecting a waiting switching state time portion, (b) Switching to the standby state, (c) Remaining in the standby state for a standby state interval time, (d) Switching from the standby state and (e) Remaining outside the standby switching state for a discharge switching state interval time, (f) wherein the waiting switching state interval time and the discharging switching state interval time are selected such that, averaged over a predetermined averaging time (?), the quotient of the waiting switching state interval times as numerator and the averaging time (?) as denominator corresponds to the waiting switching state time component.

6. Accumulator deep discharge device (10) according to one of the preceding claims, characterized in that the discharge circuit (20) is designed to automatically carry out a method with the steps (a) detecting a battery condition parameter (Pj) of a battery (12) connected to a battery terminal (14) and (b) Discharging with a waiting state time component that depends on the battery state parameter (Pj).

7. Accumulator deep discharge device (10) according to one of the preceding claims, characterized by (i) at least one temperature gauge (42) for measuring a battery temperature of batteries (12) connected to a battery terminal (14), (ii) wherein the discharge circuit (20) is designed to automatically carry out a method comprising the steps (a) detecting the accumulator temperature of at least one accumulator (12) connected to a battery terminal (14) and (b) Discharge with a waiting time component that depends on the battery temperature.

8. Accumulator deep discharge device (10) according to claim 7, characterized in that the temperature gauge (42) (a) is a thermal camera which is positioned such that at least one, in particular at least two, accumulators (12), each connected to a battery terminal (14), are located in a field of view (G) of the thermal camera and / or (b) at least one contact temperature gauge (42) for thermally contacting at least one accumulator (12) connected to a battery terminal (14).

9. Accumulator deep discharge device (10) according to one of the preceding claims, characterized in that (a) each battery terminal (14.j) is assigned a voltmeter (28.j), (b) the discharge circuit (20) is designed such that each battery terminal (14.j) can be switched into a short-circuit state in which the two poles (16.j, 18.j) are short-circuited and (c) the discharge circuit (20) is designed to automatically carry out a method comprising the steps (i) for each battery terminal (14.j) to which a battery (12.i) is connected, detecting a battery voltage (Ui2j) and (ii) Switching the battery terminal (14.j) into the short-circuit state when the battery voltage (Ui 21) or a cell voltage (Ui2.i, zeiie) of galvanic cells of the accumulator (12.i) exceeds a predetermined minimum voltage (u min ,i2.j) does not exceed.

10. Accumulator deep discharge device (10) according to one of the preceding claims, characterized in that the discharge circuit is designed to automatically carry out a method with the steps (i) detecting whether a battery is connected to a battery terminal (14) and (ii) if negative, suppressing the switching of the battery terminal (14) into the discharge switching state or switching the battery terminal (14) out of the discharge switching state. 11 . Accumulator deep discharge device (10) according to one of the preceding claims, characterized in that (a) the first battery terminal (14.1) is connected to a signature voltage source for applying a signature voltage between the first primary battery terminal pole (16.1) and the second primary battery terminal pole (18.1), (b) the signature voltage source is designed such that (i) the signature voltage is present between the first battery terminal poles (16.1, 18.1) when no battery (12.1) is connected to the first battery terminal (14.1), and (ii) a voltage different from the signature voltage is present between the first battery terminal poles (16.1, 18.1) when a battery (12.1) is connected to the first battery terminal (14.1), (c) the signature voltage differs from the battery voltage, and (d) the discharge circuit (20) is designed to automatically carry out a method comprising the steps (i) Determine the voltage between the first battery terminals (16.1 ,18.1 ) and (ii) if the voltage corresponds to the signature voltage, switching the first battery terminal to the standby state or Suppress switching of the first battery terminal from the standby state.

12. Accumulator deep discharge device (10) according to one of the preceding claims, characterized in that the discharge circuit (20) is designed to automatically carry out a method with the step: if the first battery terminal (14) is in the short-circuit switching state, regular short-time switching of the battery terminal (14) from the short-circuit switching state and back.

13. Accumulator deep discharge device (10) according to one of the preceding claims, characterized by (a) an ammeter (30) for detecting an electric current flowing through the series circuit, and / or at least one ammeter (30) for at least one battery terminal (14) connected to measure a short-circuit current (IKS) when the battery terminal (14) is in the short-circuit state, (b) wherein the discharge circuit (20) is designed to automatically detect a desired discharge current (Isoii) for a rechargeable battery (12) connected to the rechargeable battery terminal (14), in particular based on its rechargeable battery temperature and / or its battery state parameter (Pj), for at least one rechargeable battery terminal (14) and (c) Switching between discharge switching state and standby switching state with a switching frequency (f) selected such that a time-averaged actual discharge current corresponds to the desired discharge current (Isoii).

14. Method for deep discharging accumulators (12), comprising the steps (i) connecting a battery (12) to a battery terminal (14) of a battery discharge device according to one of the preceding claims and (ii) discharging the accumulator (12) and interrupting the discharge of the accumulator (12), wherein alternating between discharging and non-discharging takes place at least temporarily with a switching frequency (f) of at least 1 Hertz.

15. Method according to claim 14, characterized by the steps (i) continuously detecting a battery terminal voltage (Ui4) which drops across the respective battery terminal (14.j) at least for a plurality of the battery terminals (14.j) of the battery discharge device (20), (ii) if the battery terminal voltage (Ui4) is below a first predetermined voltage (UESJ), in particular a final discharge voltage of the respective battery terminal (14.j), reducing the discharge current to a target discharge current (I so n,i2.i), (iii) if the battery terminal voltage (Ui4 ) is below a predetermined minimum voltage (Umin,i2.j), which is lower than the final discharge voltage voltage (UES), short-circuit the respective battery terminal (14.j) and (iv) Inverting the connection voltage (U22) applied to the load connection of the accumulator discharge device (20) to an alternating voltage with a predetermined frequency (f44) and voltage (II44) and / or voltage conversion of the connection voltage (U22) to a direct voltage.