AU2020100837A4

AU2020100837A4 - Switching of several variables in the transport mode

Info

Publication number: AU2020100837A4
Application number: AU2020100837A
Authority: AU
Inventors: Michael Sternad; Markus Thannhuber
Original assignee: Einhell Germany AG
Current assignee: Einhell Germany AG
Priority date: 2019-05-27
Filing date: 2020-05-26
Publication date: 2020-07-02
Anticipated expiration: 2028-05-26
Also published as: AT17064U1; AU2020100837B4; DE202019102988U1; FR3096835B3; FR3096835A3

Abstract

: The use of an energy storage for an electric appliance shall be rendered safer and more comfortable. Therefore an energy storage (1) is provided for an electric appliance, which includes a switching device (2) for switching the energy storage (1) from a normal operating mode into a transport mode or vice versa. At least two variables of the energy storage (1) are changed when switching. 1/1 3 2 4 Fig.1 4 4 Fig.2

Description

1/1

3

2 4

Fig.1

4 4

Fig.2

Switching of several variables in the transport mode

FIELD:

The present invention relates to an energy storage for an electric tool and a corresponding electric tool.

BACKGROUND:

Energy storage for electric appliances may be realized as so-called battery packs. Such battery packs may be manufactured with lithium ion cell technology and represent a potent source of energy for electric appliances. Basically, an energy storage, however, may also be a single cell and/or be based on a different cell technology. In the following the term "battery pack" is also used to represent other energy storages.

By the energy storage electric appliances and in particular electric tools, gardening tools, household appliances, and the like are operated. In principle, however, by the energy storage also means of transport may be operated.

Commonly, for each electric appliance a normal operation is envisaged. As a rule this is characterized by several parameters, such as maximum charging end voltage, minimum discharge voltage, maximum cell temperature, maximum operating current etc. The energy storage, however, is not always in operation or in normal operation. Before starting operation or between two operating phases an energy storage is frequently transported or stored. It then is not in a normal operating phase but rather in a transport phase. For the transport of energy storages mostly particular transport regulations apply.

Lithium-ion battery packs are to be regarded as a particular safety hazard since for example the organic solvent as electrolytic medium already taken per se is combustible and thus represents a potential fire load. The greatest risk potential involved with lithium-ion cells, however, is the electrically or chemically stored energy, which may

12386549_1 (GHMatters) P113667.AU abruptly discharge in the case of internal and external short circuits and thus may trigger thermal, as well as chemical, subsequent reactions. Due to numerous incidents with lithium-ion cells during charging, during operation, during transport and storage therefore particular caution is imperative. As a rule corresponding measures are undertaken by sophisticated battery management systems monitoring the battery pack during charging, discharging, but also during transport or storage, and may take it out of operation at any time.

On the part of the legislator there are dedicated regulations for transport overland, by sea, and by air, for instance according to the guidelines UN 3480 and UN 3481. According thereto, presently all lithium-ion batteries, to start with, are subject to generally defined dangerous goods regulations ensuring safe transport. Accordingly, these are classified in Class 9 as dangerous good and accordingly are subject to accordingly applicable guidelines. Under certain conditions special provisions apply to the lithium-ion battery packs in equipments, which render the handling of the batteries in the case of transport easier. This is in particular the case for the present exemption according to special provision 188 in road and maritime traffic as well as the parts II of the packaging regulations 965 and 970 in air traffic, which may then become effective if a battery comprising lithium ions has a nominal energy in watt-hours of a maximum of 100 Wh. The extemal housing of the battery is labelled with the nominal energy in watt hours. Similar problems arise in connection with the storage of energy storages, however, without any binding provisions under public law presently existing therefor.

The energy content of a battery pack is influenced by a plurality of technical parameters, which are specifically optimized during developing or during designing the battery pack. For instance the materials and dimensions of anode and cathode as well as for instance also the used electrolyte influence an energy of the battery pack storable due to the construction design. The plurality of the technical parameters all have a certain influence on the energy or amount of energy providable by the battery pack, which ultimately also becomes manifest as nominal capacity. The development of such battery packs is concerned with balancing several contrary requirements as optimally as possible. For instance size and weight of the battery packs are to be minimized as

12386549_1 (GHMatters) P113667.AU much as possible, whilst at the same time, however, the energy to be provided by battery packs is to be maximized. Moreover, with regard to a transport of battery packs it is desirable that these do not have an excessively large energy content, however, on the other hand, the battery packs during their use should be capable of providing as much energy as possible or for as long as possible. Particularly desirable is also a long service life.

SUMMARY:

An embodiment of the present invention renders the use of an energy storage for an electric appliance safer and more comfortable.

According to the invention, there is provided an energy storage for an electric appliance, comprising: a switching device for switching the energy storage from a normal operating mode into a transport mode or vice versa, wherein at least two variables of the energy storage are changed when switching.

According to the present invention thus an energy storage for an electric appliance (in particular an electric tool, gardening tool, household appliance) is provided, which comprises a switching device for switching the energy storage from a normal operation mode into a transport mode or vice versa. Thus, for the energy storage there are defined two different modes: A normal operating mode and a transport mode. This does not rule out that also further operating modes may be envisaged. For the normal operation, i. e. when the electric appliance is to be operated in the intended way, the energy storage is in the normal operating mode. In this normal operating mode it provides for instance the desired maximum power or energy. In the normal operating mode commonly also the intended operating limits such as maximum temperature during charging and discharging, maximum discharge current etc. are observed. The transport mode, by contrast, differs from the normal operating mode in that different limits or provisions are observed. The transport mode consequently is described by different parameters/variables than the normal operating mode. In the present case it is

12386549_1 (GHMatters) P113667.AU envisaged that the two modes differ in at least two different parameters. This means that the respective parameters are variable and may attain a corresponding value for each mode. These variable parameters in the present document are referred to in short as variables.

When switching from the normal operating mode into the transport mode or vice versa, here at least two variables of the energy storage are changed. If each mode is for instance described by the variables such as maximum energy content and maximum cell temperature, the maximum energy content and the maximum cell temperature each may be higher in the normal operating mode than in the transport mode. In the transport mode the energy storage consequently must not store as much energy as in the normal operating mode and moreover the maximum cell temperature in the transport mode must also be smaller than in the normal operating mode. The respective mode, however, can also be characterized by three, four, or more variables. These variables are changed correspondingly when changing the modes for control.

In one embodiment of the energy storage the switching device comprises a manually operable switch. This means that the energy storage may be switched manually from the normal operating mode into the transport mode or vice versa. The switch may be a mechanical switch such as for instance a sliding or press switch. Alternatively, the switch may also be realized electronically. For instance the energy storage comprises a small touch screen by which a manual operation may be registered.

Moreover, it may be envisaged that the switching device comprises a sensor unit and depending on a sensor signal of the sensor unit is automatically switched from the normal operating mode into the transport mode or vice versa. This means that the energy storage receives a switch signal for instance from the electric appliance and due to this signal switches from one mode into the other. In this case thus the switching device detects for example the voltage level of a switch signal received externally and switches the mode accordingly. Alternatively, the energy storage, however, may also comprise for instance an acceleration sensor or the like, by which the energy storage itself may detect a transport phase or a transport state. Due to such sensor signal the

12386549_1 (GHMatters) P113667.AU energy storage then switches into the transport mode, if applicable. Possibly the acceleration sensor detects an extended resting phase, which is indicative of the energy storage or electric appliance being stored so that possibly also the switching into the transport mode is appropriate.

In a special embodiment the sensor unit of the switching device may be configured to receive a radio signal, in particular a GPS signal, a mobile radio signal, or a time signal, and to generate the sensor signal therefrom. From the radio signal the energy storage may for instance determine a change of location. This is in particular possible if the radio signal is a localization signal or a signal containing a location information. The switching device in this case may analyze the corresponding sensor signal and may possibly determine a change of location, which indicates a transport phase. In an alternative embodiment the sensor unit of the switching device is capable of receiving and analyzing a time signal. If the energy storage then for instance crosses a time zone, this in turn may be indicative of the energy storage being in a transport phase. Again, the energy storage then should be switched into the transport mode.

According to another embodiment of the energy storage it may be envisaged that the switching device is configured to recognize by the sensor unit an initial commissioning and in the case of having recognized an initial commissioning to switch the energy storage automatically into the transport mode. Commonly, after manufacture namely a quality test takes place, in which the energy storage needs to be initially commissioned. The switching device may then at the beginning of the initial commissioning or after the initial commissioning (e.g. a predetermined period of time thereafter) switch the energy storage automatically into the transport mode. The storage or subsequent transport taking place after the quality test thus may be safely performed.

In a further embodiment of the energy storage a charging end voltage may be one of the at least two variables, wherein same in the transport mode is smaller than in the normal operation mode. Also, in the transport mode it may be envisaged that the energy storage needs to be charged. This may for instance be the case during storage in order to avoid that the overall voltage or cell voltage of the energy storage remains

12386549_1 (GHMatters) P113667.AU below a bottom limit, whereby a damage or shortening of the service life of the energy storage can be avoided. On the other hand, the energy storage may also be used in a transport phase for the operation of an electric appliance if for instance a mobile radio device is operated when travelling in a vehicle. Also in this case tightened transport regulations apply and the energy storage must be operated in the transport mode. The fact that the charging end voltage in the transport mode is smaller than in the normal operating mode is due to the fact that during the transport the energy content of the energy storage is to be smaller than in the normal operating mode. The charging of the energy storage up to a reduced charging end voltage ensures such a reduced energy content for the transport. Especially in the case of lithium-ion batteries the reduction of the charging end voltage to for instance below 3.9 V reduces the cathode potential against lithium/lithium+ and avoids high oxidative potentials on the cathode. Also in the fully charged state the cell chemistry thus is less exploited, whereby the cell is desensitized against mechanical loads, shocks, and vibrations. In the normal operating mode the charging end voltage lies typically above 4 V.

Similarly, it may also be envisaged that a discharge voltage is one of the at least two variables and in the transport mode is larger than in the normal operating mode. In this way it may be ensured that also in a storage or transport phase the cell chemistry is spared as much as possible. Thus, for instance the discharging end voltage in the transport mode may be set to a voltage larger than 3.35 V. This avoids that the anode potential against lithium/lithium+ even in the discharged state rises excessively and the cells thus run the risk of being damaged due to erosion of the anode cover layer. This measure reduces in particular the danger of an increase in pressure within the cell (electrolyte decomposition) as well as the possibility of the corrosion of the copper current collector and internal short cuts (,,Hard Shorts") triggered thereby. The discharging end voltage in the normal operating mode typically lies at 2.5 V.

In a further embodiment of the energy storage it is envisaged that an internal pressure of the energy storage is one of the at least two variables, and in the transport mode it is smaller than in the normal operating mode. The internal pressure may be the pressure in the interior of an external sleeve of a cell pack or the internal pressure in a cell. Since

12386549_1 (GHMatters) P113667.AU the state of the energy storage during transport generally is maintained longer than is the case in a normal operation, during transport or during storage it is beneficial to avoid peak pressures that may be allowed briefly during normal operation. In this way it can be ensured that mechanical loads, shocks, and vibrations do not lead to any leakages of the energy storage.

According to a further embodiment of the energy storage a temperature, in particular a maximum temperature and/or minimal temperature, during charging or discharging of the energy storage is one of the at least two variables, and in the transport mode it is or they are different than in the normal operating mode. For instance the minimum temperature during charging in the transport mode should be larger than 100C. This reduces the danger of lithium plating during charging. By contrast, for transport or storage the maximum temperature during charging should be for example 40 °C. This protects the cell against thermal stress in the charging process. Moreover the minimum temperature during discharging should be about 5 °C. This protects the cells against a rise of the anode potential against lithium/lithium+. Further, the maximum temperature during discharging should be for instance 65 °C. This protects the cells against thermal damage and Solid Electrolyte Interface (SEI) degeneration during discharging. In the normal operating mode these minimum temperatures are generally smaller and the maximum temperatures are generally higher.

In a further embodiment a maximum admissible integral over a discharge current of the energy storage in a predetermined time interval is one of the at least two variables, and in the transport mode it is smaller than in the normal operating mode. This means that a current peak in the transport mode must be less pronounced than in the normal operating mode. Whilst in the normal operating mode a current peak may also be caused by an extremely high consumption, this is not possible or unlikely in the transport mode. A current peak in the transport mode thus is rather indicative of a short circuit, which is to be avoided as far as possible.

Further, a maximum admissible edge steepness of a discharge current of the energy storage may be one of the at least two variables, wherein the maximum admissible

12386549_1 (GHMatters) P113667.AU edge steepness in the transport mode is smaller than in the normal operating mode. The edge steepness may be an indication of a short circuit of the energy storage. Current limits tightened in this way lead to a very fast detection of short circuits and undesired discharge states of any kind. This is advantageous in particular in unpredicted situations during transport and storage.

In a particularly preferred embodiment a maximum storable amount of energy or amount of charge of the energy storage is one of the at least two variables, wherein this is smaller in the transport mode than in the normal operating mode. In this case a control device of the energy storage may be configured to limit an energy that is storable due to the construction design by the battery pack or energy storage to a predeterminable reduced energy value. Moreover, the control device may be configured to remove the limitation only if by the control device at least one predetermined unlock signal has been received so that after a corresponding charging process the energy of the battery pack that is storable due to the construction design may be provided again. Thus, the control device may automatically activate or cause a kind of protective mode, as a consequence of which the energy that is storable by the battery pack is automatically limited to the predeterminable reduced energy value. Via a sensor system for instance information about voltages, temperatures, and the like of the battery cells may be provided and monitored. The automatic limitation may for instance also be effected via a cloud-based service, via an Internet of Things (loT) application, or the like.

In a further embodiment of the energy storage according to the invention it may be envisaged that a re-start condition, which contains in particular a time duration after an overcurrent event, of the energy storage is one of the at least two variables, and in the transport mode it is different than in the normal operating mode. This means, when switching from the normal operating mode into the transport mode or vice versa, the re start condition (failure recovery) is changed. In particular these re-start conditions in the transport mode may be designed in a more conservative way. Thus, for instance after a steep current peak in the transport mode a minimum waiting time of 30 s may be set, whereas the minimum waiting time in the normal operating mode for instance amounts

12386549_1 (GHMatters) P113667.AU to only 10 s. Moreover, in the transport mode it may be envisaged that in the case of ten peak current incidents within 10 minutes a permanent deactivation of the energy storage until the next recharging is effected. Such permanent deactivation possibly is not envisaged in the normal operating mode, for which reason consequently the re-start condition changes when switching between transport mode and normal operating mode. Such tightened failure recovery scenarios protect the battery pack, in particular in the context of unpredicted discharge conditions, for instance also during transport and storage.

According to a further advantageous embodiment of the energy storage the switching device is configured to facilitate the switching of the energy storage from a normal operating mode into a transport mode or vice versa only on the basis of an unlock signal. Preferably, the unlock signal of the switching device is only provided if a predetermined unlock code is provided (e. g. at a user interface by corresponding input). In this way the switching may be consciously performed only in such a way that it cannot be triggered inadvertently, accidentally, or unintentionally, for instance by shocks or exertion of destructive influence. The energy storage or the battery pack consequently can only be switched from the one mode into the other if the user performs this as a conscious action and thereby confirms his or her intention. This may be effected consciously by the user e. g. after the battery pack has arrived at its destination. The conversion of the battery pack therein is preferably effected by transfer of a key information effecting the transition in the firm ware and programmatically reconfigures the battery pack. This key information may for instance be effected by Bluetooth, WiFi, or Extended WAN, or else by plugging for instance a component or by input of a dedicated key combination. The transfer of the key to the battery management system therein equals a confirmation of the user to the effect that the transport or storage process is completed and the battery pack has reached its destination and the user now would like to use the battery pack with a different power configuration and a different energy content. Preferably, the battery pack with new expanded energy content or configuration for normal operation is available to the user only after transfer of the key information and subsequent charging.

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The battery pack may acknowledge the changeover for instance by changing the LED colour from green to red.

According to the invention, there is also provided an electric tool with an energy storage of the above-named kind. Depending on the setting of the energy storage into the transport mode or the normal operation mode then also the electric appliance may only be operated in the corresponding mode. This means that the energy storage for the electric appliance possibly provides the energy only in the way allowed by the current mode.

BRIEF DESCRIPTION OF DRAWINGS:

The present invention is explained in more detail by reference to the enclosed drawings. These show in:

Fig. 1 a schematic view of an energy storage comprising a switching device for an electric appliance; and

Fig. 2 a schematic representation of a data storage of an energy storage in the normal operating mode and in the transport mode.

DETAILED DESCRIPTION OF EMBODIMENTS OF INVENTION:

The embodiments explained in more detail in the following represent preferred embodiments of the present invention.

According to the example of Fig. 1 an energy storage 1 is to be provided for an electric appliance, which is not shown in further detail. The energy storage is preferably a battery pack and specifically a lithium-ion battery pack. The electric appliance may be an electric tool, a gardening tool, a household appliance, or the like. The energy storage 1 supplies electric energy for the operation of the electric appliance.

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The energy storage 1 is to be operated in at least two different modes. These include a normal operating mode, in which the energy storage is employed in the intended operation. In this connection the energy storage supplies electric energy to the electric appliance in an intended way. The energy storage, however, may also be operated in the transport mode. In this case the energy storage is also configured for transport or storage.

Each mode is characterized by at least two specific values of operating parameters, i. e. variables, which represent the configuration of the energy storage or the configuration of its battery management system. The energy storage 1 for this purpose comprises possibly integrated in the battery management system - a switching device 2, which receives a signal from an input device 3, due to which it is switched from the normal operating mode into the transport mode or vice versa. The input device 3 may comprise a manual switch, by which it may be manually switched into the respective mode. Alternatively or additionally, the input device 3 may comprise a sensor in order to automatically generate the signal for the switching device. Thus, the energy storage 1 or the battery management system is in a position to automatically change the operating mode. The input device 3 may for instance comprise a radio interface, by which a radio signal, in particular a GPS signal, a mobile radio signal, or a time signal may be received and optionally preprocessed.

Possibly the input device also comprises an encoding unit, by which key information must be received in order to cause the switching unit 2 to switch the respective mode. Also this key information may be wirelessly transmitted by radio (e. g. Bluetooth, WiFi, etc.) Alternatively, the key information, of course, may also be input by a specific plug system or a specific key combination. For instance, the energy storage may be configured in such a way that the energy storage or battery pack is only available to the user in the new mode (e.g. with expanded energy content) after transfer of the key information and subsequent charging. The battery pack acknowledges the changeover for instance by changing the LED colour from green to red. After the changeover possibly a higher power or a higher energy content is available. If the user at a later stage possibly would like to work more cycle-consciously again, i. e. attaches

12386549_1 (GHMatters) P113667.AU importance to a longer service life again, or would like to prepare the battery pack for a transport, by application of the key the user is provided with the option of reconverting the battery into the original configuration. By employing the key the user for instance is allowed to exclusively change between these two safe product configurations.

After storage and transport in the transport mode, at the destination the user may switch the battery pack into the normal operating mode. In this way the switching from one mode into the other is effected exclusively consciously. A battery pack in the normal operating mode according to current provisions may for instance only be passed as cargo of hazardous goods class 9 with corresponding documentation and packaging as well as in observation of the procedural guidelines to freight carriers, logistics companies, or the postal service. If the battery pack, by contrast, is switched into the transport mode and thus is preferably charged with reduced energy, e. g. according to the current special provision 188 ADr it may be dispatched under easier conditions overland.

When switching the mode by the switching device 2, at least two variables, i. e. parameters, are changed. This means that the normal operating mode differs in at least two variables from the transport mode. These variables may for instance concern the charging end voltage, the discharging end voltage, the intemal pressure, the temperature, the discharge current (in particular an integral over the discharge current or an edge steepness of the discharge current), a maximum storable amount of energy or amount of charge, a re-start condition, and the like. The values for the corresponding variables are changed by the switching device 2 for instance in a data storage 4 of the battery pack or battery management system, which equals a switching.

Fig. 2 schematically shows the storage content of the data storage 4 in a normal operating mode (index n) and in a transport mode (index t). In the present example for the two modes a plurality of variables is provided, of which only six in each case are drawn in concrete terms in Fig. 2. Thus, the normal operating mode is characterized by the variable values V1n, V2n to V6n. By contrast, the transport mode is characterized by the variable values V1it, V2t to V6t. When switching from the normal operating mode into

12386549_1 (GHMatters) P113667.AU the transport mode consequently for instance the variables V1 to V6 are changed. In concrete terms, instead of the values V1n to V6n they get the values V1it to V6. Of course, the normal operating mode may differ from the transport mode also by a different number of variables. However, it is invariably at least two variables, which are characteristic of each mode. Possibly, however, when switching the mode also more than six variables may be switched.

When switching back from the transport mode into the normal operating mode, in the data storage 4 then the variable values V1n to V6n are stored again instead of the variable values V1itto V6t.

By switching from the normal operating mode into the transport mode a safe transport and a safe storage of the energy storage is possible. The, at times, fast movements in transport situations, whether by ship, airplane, train, or truck, are thus less dangerous. In particular traffic-related accelerations, vibrations, shocks etc., to which the battery packs are exposed unattended and in which, unlike in operation, it is not possible to intervene observantly as desired or at any time, represent less hazard to the battery packs. This is beneficial in typical transport situations, in which in the majority of cases several, if not many (pallets, Eurotainer) batteries are stowed densely packed on means of transport. A single battery pack thus is not directly accessible and in cases of thermal damage adjacent battery packs may be affected. Besides, in the case of transport an invariably remaining risk of accident, overturn, or unplanned exposure to media (for instance fire-fighting water, rainwater, seawater, etc.) exists, which even in the case of lithium-ion battery packs must not lead immediately to uncontrolled short circuits, fires, or explosions as a consequence. All these situations may be eased by the switching of a battery pack into the transport mode.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

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It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

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LIST OF REFERENCE SIGNS:

1 energy storage 2 switching device 3 input device 4 data storage V1n to V6n variable values in the normal operating mode Vit to V6t variable values in the transport mode

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Claims

CLAIMS:

1. An energy storage for an electric appliance, comprising: a switching device for switching the energy storage from a normal operating mode into a transport mode or vice versa, wherein at least two variables of the energy storage are changed when switching.

2. An energy storage according to claim 1, wherein the switching device comprises a sensor unit and depending on a sensor signal of the sensor unit automatically switches from the normal operating mode into the transport mode or vice versa.

3. An energy storage according to any one of the preceding claims, wherein a charging end voltage is one of the at least two variables and in the transport mode is smaller than in the normal operating mode, or a discharging end voltage is one of the at least two variables and in the transport mode is larger than in the normal operating mode.

4. An energy storage according to any one of the preceding claims, wherein a temperature, in particular a maximum temperature and/or minimum temperature, during charging or discharging the energy storage or a re-start condition, containing in particular a time duration after an overcurrent event, of the energy storage is one of the at least two variables and in the transport mode is different than in the normal operating mode.

5. An energy storage according to any one of the preceding claims, wherein a maximum admissible integral over a discharge current of the energy storage in a predetermined time interval or a maximum admissible edge steepness of a discharge current of the energy storage or a maximum storable amount of

12386549_1 (GHMatters) P113667.AU energy or amount of charge of the energy storage or an internal pressure of the energy storage is one of the at least two variables and in the transport mode is smaller than in the normal operating mode.

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