EP3649680A1

EP3649680A1 - Master control device for a battery system

Info

Publication number: EP3649680A1
Application number: EP18738257.7A
Authority: EP
Inventors: Jan Salziger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-07-05
Filing date: 2018-07-02
Publication date: 2020-05-13
Also published as: WO2019007879A1; CN110832689A; DE102017211468A1

Abstract

The invention relates to a battery system (100) having a plurality of batteries (103, 104, 105, 106), which are connected to a CAN bus, wherein each of the plurality of batteries (103, 104, 105, 106) comprises a battery management system, which has at least one master component (214), which can act as a master control device, characterized in that one of the master components is intended to act as a central master control device, the central master control taking responsibility for communication between a vehicle control unit, the plurality of batteries, and a high-current bus.

Description

description

Master control unit for a battery system prior art

The invention relates to a master control device for a battery system.

Document DE 102012000585 A1 describes a battery assembly for a motor vehicle having a plurality of battery modules, each one

Battery module is coupled to a respective control unit and between each adjacent battery modules a high-voltage line to the electric

Coupling is provided, wherein the control units are each designed to exchange data via the high-voltage line.

Document DE 102014200111 A1 describes a battery management system for monitoring and regulating the operation of a rechargeable battery comprising a plurality of batteries, comprising a control unit

Separation unit for galvanic isolation of the battery from one

Consumer device, a plurality of at least one battery cell to be assigned each cell monitoring units and a communication system for transmitting and receiving data includes.

The object of the invention is to connect batteries with different voltage values to a high current bus.

Disclosure of the invention

A battery system has several batteries connected to a CAN bus

are connected. The several batteries each include one Battery management system, wherein the battery management system each has at least one master component that can act as a master control unit. According to the invention, one of the master components is intended to function as a central master control unit. The central

Master controller takes over a communication between a

Vehicle control unit, the multiple batteries and a high current bus.

The advantage here is that the different batteries are displayed relative to the vehicle control unit as a large battery, whereby the battery system does not have to be designed specifically for the interconnection of different batteries.

In a development, the multiple batteries have different

Voltage values.

The advantage here is that no separate matching circuit for connecting the batteries is needed on the high current bus.

In another embodiment, that battery performs the function of the central master control unit, which is physically connected as the first to the Can bus.

The advantage here is that the arrangement is simple.

In a further development, the voltage value of the battery, the

performs the function of the central master controller, approximately 0 V.

The advantage here is that even empty batteries can take over the function of the central master control unit.

In a further embodiment, the battery which performs the function of the central master control unit is not set up to switch on the high current bus. The advantage here is that even batteries that are not able to switch to the high current bus due to a restriction, can still take over the communication between the vehicle control unit, the multiple batteries and the high current bus.

In a development, the central master control unit is set up to switch the several batteries to the high current bus.

It is advantageous here that the data volume on the CAN bus is low.

An electric vehicle includes a battery system as described above. In a particularly advantageous embodiment, the electric vehicle is an electric two-wheeled vehicle, in particular a scooter. Further advantages will become apparent from the following description of

Embodiments or from the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described below with reference to preferred

Embodiments and attached drawings explained. Show it:

1 shows a battery system with two consumers, Figure 2 shows a detail of the battery system of Figure 1, and

3 shows a method for connecting a battery to a

Hochstrombus. 1 shows a battery system 100, a vehicle control unit 101, a Can

Bus 102, a high current bus 109 and two consumers, a motor 107 and a charger 108. That means the Can bus 102 and the high current bus 109 are parts of the vehicle system and connected to the battery system 100. The battery system 100 includes a plurality of batteries 103, 104, 105, and 106. There are exemplarily four batteries 103, 104, 105, and 106 here shown. The batteries 103, 104, 105 and 106 and the consumers 107 and 108 are physically connected to the vehicle control unit 101 via the Can bus 102. Thus, all Can signals can be sent to all connected batteries 103, 104, 105 and 106 and consumers 107 and 108. The batteries 103, 104, 105 and 106 are connected by means of relays 110, 111, 112 and 113 and / or Vorladeschaltung with the high-current bus 109. The

Vorladeschaltungen are each connected in parallel to the individual relays 110, 111, 112 and 113. The precharge circuits each include one

Series connection of a switch and a precharge resistor. The

High current bus in particular has a voltage of 48 V. To Can bus 102 and / or the high current bus 109 more consumers can be connected. In addition, regenerative components such as generators can also be connected.

FIG. 2 shows a battery system 200 and a vehicle control unit 201. The battery system 200 has a section of the vehicle

Battery system 100 of Figure 1 with three batteries 203, 204 and 205. The Can bus and the high current bus of Figure 1 are not shown, but in

Battery system 200 available. Each battery 203, 204 and 205 each has a battery management system. Each battery management system includes slave components 215, 216 and 217 that perform slave functions. The term slave functions are understood here as functions that determine the battery parameters of the respective battery, for example

State of charge, aging state, internal resistance and currently usable capacity. Each battery management system additionally has master components 214 that can execute or execute master functions. Introduces

Battery management system a master function off, this battery management system 215, 216 and 217 takes over the tasks of a

Master control unit for the high current bus. It is thus a central master control unit that is temporarily activated or virtual. The

Execution of the master function or master functions can be activated in each battery 203, 204 and 205, but not simultaneously. The role of the temporary master controller is preferably taken from the battery, which is temporally first available on the Can bus. In other words, the role of the master controller is merely the connection of the battery to the CAN bus dependent. Thus, even empty batteries or a battery that is unable to supply or remove power from the high current bus due to limitations may take on the role of master controller.

That is, during operation of the battery system 200, the vehicle control unit 201 only communicates with the temporary master controller. The temporary master control unit communicates with all the batteries connected to the Can bus 203, 204 and 205 and other consumers, such as electric motor or charger. All slave components of batteries 203, 204 and 205 communicate directly with the temporary master controller. In other words, the vehicle control unit 201 does not need to communicate directly with the individual batteries 203, 204 and 205 during operation. If additional consumers are present, the task of the temporary master control device can also be taken over by the control devices of the further consumers.

If the temporary master control unit fails during operation of the battery system, then the role of the temporary master control unit can be taken over by any other battery or any other control unit connected to the CAN bus, eg. B. also from the control units of the consumer.

The slave components and the master components can be implemented as software.

The temporary master control unit takes over various tasks in the battery system, for example, the Zuschaltfreigabe the batteries 203, 204 and 205, the high current bus or the determination of the permissible total current.

When Zuschaltfreigabe the temporary master control unit acts as a central master battery management system of different batteries and represents the different batteries compared to the vehicle control unit 201 as a single battery. The battery system 200 thus does not need to be designed specifically for the interconnection of different batteries. When determining or predicting the permissible total current, the temporary master control unit acquires the currents that are permissible at the current time and determines the permissible total current.

FIG. 3 shows a method 300 for connecting a battery to a battery

Hochstrombus. The method starts with a step 305 in which

Voltage values of the batteries arranged or connected to a CAN bus are detected by a temporary master control unit. For this purpose, the slave components of each battery management system send the

Voltage value of the respective or own battery to the temporary one

Master controller. In a following step 310, the operating mode of each battery connected to the CAN bus is determined by the temporary master controller. A distinction is made between the two operating modes "unloading" and "loading". If the voltage value of the individual battery is higher than a predefined threshold value, the operating mode of the respective battery is "discharged." If the voltage value of the individual battery is less than the predetermined threshold value, the operating mode of the respective battery is "charging". The operating mode or state or use "unloading" can be advantageously transmitted from the vehicle system to the battery system by the state "ignition key turned" is detected. The operating mode or the state or use "charging" can be determined by connecting the system to a charger, Charging or discharging can in principle also take place in the other operating states, however, the corresponding connection is advantageous on the basis of the pending use The states of all relays are detected by the temporary master control unit in a following step 315. The operating mode is evaluated in a following step 320. If the operating mode is "unloading", the relay position of the individual batteries is evaluated in a following step 325. Are all relays open, d. H. there is still no battery connected to the high current bus, so in a following step 330, a first battery, in particular via a precharge circuit, connected to the high current bus. It is the battery that is the largest

Voltage value. The term "first battery" is understood to mean the battery which, in terms of time, is the first to be connected to the high-current bus controllable current source, a series connection of a resistor and a controllable switch, or other suitable methods to charge a capacitor to a defined voltage which are connected in parallel with the relay of the zuzuschaltenden battery. In other words, the temporally first battery, which is switched to the high current bus, is switched to the high current bus via a precharge circuit, since the high current bus usually comprises high capacities. The precharge circuit charges the capacities of the battery to be connected, so that the voltage value of the

Hochstrombusses is brought to the same voltage value as the zuzuschaltende battery. Thus, high voltage differences are avoided to the high current bus when connecting the battery. Furthermore, high charging currents of the high current bus capacitance are avoided, thereby destroying the components, e.g. Capacitor and relay, is prevented and aging of the components is not accelerated. In a following step 335 it is checked whether the voltage difference between the

zuzuschaltenden battery and the high current bus is smaller than a suitable limit for the components. This can e.g. at 1V. If this is the case, in a following step 340, the relay of the zuzuschaltenden battery is closed, whereby the Vorladeschaltung is bridged. The battery system now supplies power that can be taken by the consumer. This reduces the state of charge of the first battery, d. H. the voltage of the first battery decreases.

If not all relays are opened in the evaluation of the states of the relays in step 325, ie at least one relay closed, the method continues with step 345, in which with the help of the temporary master control device in each case a voltage difference between each not yet switched battery, ie each switchable battery, and the high current bus is determined. Each switchable battery sends its voltage value by means of a slave component to the temporary master control unit. In other words, the charge state difference of the first battery already connected to the high current bus or the already connected batteries and the switchable batteries is determined. In a following step 350, the battery is determined, which is temporally switched as next battery to the high current bus. In this case, that battery is selected which has the lowest voltage difference to

Has high current bus or which has the voltage value of the first battery or already connected batteries. In other words, the voltage value of the already connected to the bus batteries reaches the

Voltage value of another battery not yet switched on, so this additional battery can be switched on in terms of time as the next on the high current bus, d. H. the battery with the next lower voltage value is declared or determined as the battery to be connected.

In a following step 355, the total current is determined in the already switched on the high-current bus batteries. In a following step 360, it is checked whether the voltage difference of the battery to be connected to the high current bus is less than 1 volt and whether the state of charge difference to the already switched batteries is less than a certain percentage, this can e.g. 5%, and the amount of total current is less than the product of 10 amperes times the number of batteries already connected. If this is the case, then in a following step 365, the zuzuschaltende battery is switched to the high current bus.

If the magnitude of the total current is greater than the product of 10 amps times the number of batteries already connected, a change-over-request command is sent to the can bus in a subsequent step 370. This command involves lowering the total current In a following step 375, it is detected whether the total current falls below a predefined threshold value, for example 10A times the number of batteries connected in. If so, in a following step 380 the battery to be connected can be switched to the

High current bus switched. In a following step 385, the lowering of the total current is ended. The method 300 continues with step 345, if not all batteries are switched on. In the "Discharge" operating mode, all batteries that have not yet been switched on can therefore be low in the order of high voltage value

Voltage value can be switched on.

If the operating mode is "load", it is checked whether all relays are open in step 390 following step 320. If this is the case, then in a following step 395 the first battery is switched to the high current bus via a precharge circuit In a following step 400, it is checked whether the voltage difference between the high current bus and the battery to be connected is smaller than 1 V. If this is the case, in a following step 405 the relay becomes The first battery is closed and the first battery is thus directly connected to the high current bus

Chargers, can supply power. This will increase the state of charge and the voltage or voltage level of the battery.

If at least one relay is closed in the evaluation of the relays in step 390, the method is continued with step 410, in which in each case the voltage difference between each not yet connected battery, d. H. each switchable battery and the high current bus is determined. In a following step 415, the battery to be connected is determined. In this case, the battery which has the lowest value is selected

Voltage difference to the high current bus has. In other words, the voltage value of the batteries already connected to the bus reaches the voltage value of another battery which has not yet been switched on, so that this additional battery can be switched on in terms of time as the next to the high current bus, ie. H. the battery with the next higher voltage value is declared or determined as the battery to be connected.

In a following step 420, the total current is determined in the already switched on the high current bus batteries. In a following step 425, it is checked whether the voltage difference of the zuzuschaltenden battery to the high-current bus is less than 1 volt and whether the state of charge difference to the already switched batteries is less than 5% and the amount of Total current is less than the product of 10 amperes times the number of already switched batteries. If this is the case, then in a following step 430 the zuzuschaltende battery is switched on the high current bus.

If this is not the case and the total current amount is greater than the product of 10 amperes times the number of batteries already connected, then in a following step 435 a change-over-request command is sent to the can bus The command comprises lowering the total current through the vehicle controller, thereby avoiding high currents, and in a following step 440, it is detected whether the total current is one

predefined threshold, for example, 10A times the number of already switched batteries. If this is the case, the battery to be connected can be switched to the high-current bus in a following step 445. In a following step 450, the reduction of the total current is terminated by the total allowable current of the system again fully based on the permissible currents of the batteries connected to the

Vehicle control unit is communicated.

In the operating mode "charge", all batteries that have not yet been connected can thus be switched to the highest in the sequence from the lowest voltage value

Voltage value can be switched on.

In one embodiment, which can be applied to both the "unload" operating mode and the "charge" operating mode, the temporary master control unit for precharging the high-current bus or its intermediate circuit may also use a plurality of the batteries not yet switched on by the precharging circuits of the individual batteries not yet

switched batteries are used. This is explained as an example for the operating mode "charging." The first battery, which plays the role of the battery to be connected, is the battery which is the lowest

Voltage value. The virtual master controller can now use the

Do precharge the DC link using a not yet switched battery, which has a much higher voltage than the zuzuschaltende battery. As a result, the voltage potential of the

Hochstrombusses faster on the voltage of zuzuschaltenden Battery brought, ie an early connection of zuzuschaltenden battery is possible. In addition, it is advantageous to use the energy for the precharge from a battery with a higher voltage value, since thus the voltage difference of the battery with the higher voltage value for

High current bus reduced and consequently can switch on this at a later date faster. If the voltage potentials of the battery to be connected and the high current bus are approximately the same, the temporary master control unit terminates the precharge.

If the precharge circuit of the zuzuschaltenden battery is overloaded or defective, the temporary master controller can determine another battery for pre-charging.

If the high current bus is already electrically charged during the precharge, e.g. by consumers that can not be switched off or not switched off, the selected precharge circuit can not regulate the high current bus to the same voltage level. This is because each precharge circuit is current limiting because the precharge circuit acts like a voltage divider with the already connected load. To increase the precharge current, the temporary master controller may precharge several precharge circuits of different batteries. This reduces the voltage difference between the zuzuschaltenden battery and the high-current bus.

Claims

claims

A battery system (100) having a plurality of batteries (103, 104, 105, 106) connected to a CAN bus, the plurality of batteries (103, 104, 105, 106) each including a battery management system

Battery management system each having at least one master component (214), which can act as a master control unit, characterized in that one of the master components is determined as a central

To act master control unit, wherein the central master control unit takes over a communication between a vehicle control unit, the plurality of batteries and a high current bus.

2. Battery system (100) according to claim 1, characterized in that the plurality of batteries (103, 104, 105, 106) have different voltage values.

3. Battery system (100) according to any one of claims 1 or 2, characterized

characterized in that the battery (103, 104, 105, 106) performs the function of the central master control device, which is physically first connected to the Can bus.

4. Battery system (100) according to any one of the preceding claims, characterized in that the voltage value of the battery (103, 104, 105, 106), which performs the function of the central master control unit, is approximately 0 V.

5. Battery system (100) according to any one of the preceding claims, characterized in that the battery, the function of the central

Master control unit is executed, is not set up to the Hochstrombus zuzuschalten.

6. Battery system (100) according to any one of the preceding claims, characterized in that the central master control unit is adapted to switch the plurality of batteries (103, 104, 105, 106) to the high current bus.

7. Electric vehicle with a battery system (100) according to one of the preceding claims.

8. Electrical vehicle, characterized in that the electric vehicle is a bicycle.

9. Electronically controllable precharge circuit, which is connected to a battery system according to one of claims 1 to 6, characterized in that the precharge circuit via a communication line from the central master control unit can be switched on and off as needed.