Patent Application
20190109463
The present invention relates to a device and a method for regulating a battery charging process, and to a system having such a device.
Rechargeable batteries, also known as secondary batteries and referred to hereafter simply as batteries, find applications in many fields of technology. An application example is their use in drivetrains in at least partially electrically driven vehicles. One example of such vehicles are electrically operated vehicles on scheduled routes. Electric drives are therefore advantageous for vehicles on scheduled routes because the travel times along the route are usually limited and separated by periods (driving breaks), in which the battery can be charged.
When charging batteries, especially when the battery to be charged has a low charge state at the start of the charging process, a high current amplitude can occur.
The charging power is determined in this case by the current battery voltage and the amplitude of the charging current.
To prevent the charging current that is produced from damaging the battery or other components, in the so-called CCCV charging process (CCCV stands for constant current constant voltage) the charging process is regulated by the charger such that in a first phase, a charging current of constant current amplitude is provided. This is achieved by accordingly regulating the current in the first phase.
The charging device can additionally or alternatively be configured to determine the current amplitude using a battery-side preferred charging current amplitude Ibev and/or a battery-side preferred charging voltage Ubev.
The battery and/or a battery management system can be designed accordingly, to determine the preferred charging current amplitude and/or the preferred charging voltage Ubev and also to signal them.
According to the invention, a device according to claim 1 and a method according to claim 11 for regulating a battery charging process are provided.
The device comprises an input for a signal connection, via which input a charging current amplitude Ibev preferred for charging can be signaled to the device, and an output for a further signal connection, via which output the device can signal a current amplitude Ianf which is required for charging.
The device is additionally designed to receive signaling of a charging current amplitude Iemf, received from the battery via the signal connection, and to use the received charging current amplitude Iemf together with the preferred charging current amplitude Ibev for determining the required current amplitude Ianf.
The method according to the invention comprises appropriate steps.
Since the received charging current amplitude Iemf is used together with the preferred charging current amplitude Ibev for the determination of the required current amplitude Ianf, the current amplitude Ianf can be determined in such a way that current amplitude losses between the charging device and the battery, which can be caused, for example, by consumers connected in parallel, can be compensated without direct knowledge about causes of the current amplitude losses.
In a preferred embodiment, a charging voltage Ubev preferred for charging the battery can also be signaled to the device, and the device is designed to signal to the charging device a charging voltage Uanf required to charge the battery.
This offers advanced control options for the device, by means of which the charging process can be better regulated.
In particular, the required charging voltage Uanf can be equal to the preferred charging voltage Ubev.
This will ensure that the charging device can charge the battery with the preferred charging voltage at the battery side.
The device can be configured in such a way that via a further signal connection, at least one charging voltage Uber supplied for charging the battery can be additionally signaled. The device can then be configured to determine the required current Ianf using the supplied charging voltage Uber.
The device is thereby upgraded to take into account the supplied charging voltage Uber during the charging regulation, resulting in an even more precise regulation.
The device is additionally configured such that in addition, at least one current amplitude Iber supplied for charging the battery can be signaled to said device. The device is then configured to determine the required current amplitude Ianf using the supplied current amplitude Iber.
The device is thereby upgraded to take into account the supplied charging current Iber during the charging regulation, resulting in an even more accurate regulation. In particular, it is then possible to determine whether the received current amplitude Iemf corresponds to the supplied current amplitude Iber.
The device can furthermore be designed to determine the output signal such that the required current amplitude Ianf compensates a difference between the preferred current amplitude Ibev and the received current amplitude Iemf.
Thus, current amplitude losses between the charging device and the battery, which can be caused, for example, by consumers connected in parallel, are compensated without direct knowledge about the causes of the current amplitude losses.
The device can be further designed to determine the output signal such that the required current amplitude Ianf is proportional to the difference between double the preferred charging current Ibev and the received current amplitude Iemf: Ianf˜2*Ibev−Iemf.
This is one form of the compensation. In particular, Ianf=2*Ibev−Iemf can apply.
According to the invention, a system according to claim 8 is also presented. The system comprises the device presented according to the invention and the battery. The battery comprises at least one voltage input, via which the battery can be charged by the charging device. The battery also comprises at least one output for the signal connection.
In a preferred embodiment the system further comprises the charging device, wherein the charging device comprises a voltage output connected to the voltage input of the battery for supplying a charging current for charging the battery with a current amplitude Iber, and an input for the other signal connection.
The system can be designed such that a preferred charging voltage Ubev for charging the battery can also be signaled to the device, and the device is designed to signal to the charging device a charging voltage Uanf required to charge the battery, wherein the charging device can then be configured to determine the current amplitude Iber using the required charging voltage Uanf and a supplied charging voltage Uber with which the charging current is supplied.
In a preferred embodiment the method according to the invention comprises determining a voltage Uerf required for further charging using the preferred current amplitude Ibev and transmitting the determined required voltage Uerf to the charging device.
The above-described properties, features and advantages of the present invention and the manner in which these are achieved will become clearer and more comprehensible in conjunction with the following description of the exemplary embodiments, which are explained in more detail in connection with the drawing. Shown is:
The charging device 200 is connected to the battery 400 via a voltage supply connection 700 for supplying a charging current. As an example, along the voltage supply connection 700 two consumers 500, 600, such as a heater and a ventilation system, are connected in parallel. The return connection is effected in the example shown via ground contacts.
In normal operation, when the battery 400 is not being charged by the charging device 200, the consumers 500, 600 are supplied with power by the battery 400 as necessary. In the charging operating mode, when the battery 400 is being charged by the charging device 200, the consumers 500, 600 are supplied with power by the charging device 200 as necessary.
The device 100 comprises a logical or physical input for a signal connection 403, 301, via which input the battery 400 signals a charging current amplitude Ibev preferred for charging.
The device 100 further comprises a logical or physical output for a further signal connection 102, via which the device 100 signals to the charging device 200 a current amplitude Ianf which is required for charging and, if appropriate, for supplying the auxiliary systems 500 and 600.
The device 100 comprises a further logical or physical input for a signal connection 201, via which the charging device 200 signals the supplied current amplitude Iber to the device 100. The signal connection 201 is optional and in a further embodiment comprises signaling of the supplied voltage Uber.
The device 100 additionally comprises a further logical or physical output for a further signal connection 103, via which the device 100 signals the supplied current amplitude Iber of the charging current to the battery 400. The signal connection 103 is optional and in a further embodiment comprises signaling of the supplied voltage Uber.
Signal connections 102, 201, 103, 301 and 403 can be implemented by a bus system. The bus system can also implement the voltage supply connection 700.
The device 100 also receives signaling of a charging current amplitude Iemf from the battery 400, via the signal connection 403, 301. The device 100 uses the received charging current amplitude Iemf together with the preferred charging current amplitude Ibev for the determination of the required current amplitude Ianf. In a further embodiment, the signal connection 403, 301 comprises signaling of a preferred charging voltage Ubev.
In the illustrated example, the signal connection 403, 301 comprises a battery management system 300, which receives via partial signal connection 403, from the battery 400, signaling of the received charging current amplitude Iemf and the preferred charging current amplitude Ibev, and which via partial signal connection 301 signals the received charging current amplitude Iemf and the preferred charging current amplitude Ibev to the device 100.
The device 100 is further designed to determine the output signal such that the required current amplitude Ianf compensates a difference between the preferred charging current amplitude Ibev and the received charging current amplitude Iemf.
In this way, current amplitude losses between the charging device 200 and the battery 400, which can be caused by consumers 500, 600 connected in parallel along the voltage supply connection 700, for example, a heater and a ventilation unit or an air-conditioning unit, are compensated without direct knowledge about the causes and the amount of the current amplitude losses.
The compensation can take place in different ways. The aim of the compensation is to minimize the difference between Ibev−Iemf for each point in time, in particular, such that Ibev−Iemf is always equal to zero.
In one exemplary embodiment the required current amplitude Ianf is proportional to the difference between double the preferred charging current Ibev and the received charging current amplitude Iemf:
Ianf˜2*Ibev−Iemf. In a specific embodiment of this example Ianf=2*Ibev−Iemf. If a difference exists between Ibev and Iemf, this will be immediately and fully compensated by the regulation. If, on the other hand, there is no difference, then Ianf=Ibev.
The device can also be upgraded to the effect that it also provides protection for the battery against being energized too highly during load shedding, in other words if a parallel-connected consumer is switched off during the charging process. This can be achieved if the device 100 is designed to determine, in addition to the required current amplitude Ianf, a voltage Uerf required for supplying the preferred current amplitude Ibev and to transfer it to the charging device. The preferred current amplitude Ibev is equivalent namely to a charging state of the battery and therefore to a voltage Uerf required for further charging, which is less than a final voltage Ufin, to which the charging process is fundamentally limited and with which an almost fully charged battery must be charged. If load shedding is taking place, this causes a voltage limitation on the required voltage Uerf, that the charging device only delivers the current amplitude to be required according to load shedding. In particular, an independent voltage limitation on the final voltage Ufin is unnecessary, since the required voltage Uerf asymptotically approaches the final voltage Ufin with increasing charge state of the battery.
In an exemplary embodiment of the method according to the invention, a charging process of a battery is regulated, wherein the charging process takes place by means of a charging device in accordance with a transmitted required current amplitude Ianf. To this end a current amplitude Ibev preferred for charging the battery is received, for example from the battery or from a control unit. In addition, a current amplitude Iemf received by the battery is received, for example from the battery or from the control unit. Then, a required current amplitude Ianf is determined using the received current amplitude Iemf and the preferred current amplitude Ibev. Finally, the determined required current amplitude Ianf is transmitted to the charging device.
The invention can be used, for example, for charging processes of at least partially electrically driven vehicles. The result achieved by the compensation is that the battery reaches a specific state of charge within a predetermined charging period, regardless of whether the additional consumers are operating or not. This is particularly advantageous for electric or hybrid powered vehicles on scheduled routes with charging periods that are limited by scheduled travel times.
Although the invention has been illustrated and described in greater detail by means of preferred exemplary embodiments, the invention is not restricted by the examples disclosed and other variations can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2016 205 360.4 | Mar 2016 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/054906 | 3/2/2017 | WO | 00 |
