DE102013204513A1 - Method and device for increasing the safety when using battery modules - Google Patents

Abstract

The invention is based on a method for bringing about a safe state of a battery module of a vehicle, wherein the current state of the battery module is continuously checked and evaluated and the safe state of the battery module that is to be brought about is such a state, in the effects of a defective battery module are reduced or the probability of damage to the battery module is reduced, the induction of the safe state being carried out as a function of a parameter which suggests an internal short circuit of the battery module.

Description

Field of the invention

The present invention relates to a method and a device for increasing the safety in the use of battery modules according to the preamble of the independent claims.

State of the art

Safety concepts for intrinsically safe battery modules are known from the prior art. The state of the art includes, for example, fuses and measures which prevent or counteract excessive currents and voltages in the region of the battery modules. For example, in the DE 10 2011 113 798 A1 discloses a modular battery in which to avoid battery-related dangers individual series and parallel circuits of the battery module can be switched on and off.

Disclosure of the invention

The invention is based on a method for establishing a safe state of a battery module of a vehicle, wherein the current state of the battery module is continuously tested and evaluated and the safe state of the battery module to be brought about is such a state in the effects of a defective battery module be reduced and / or the probability of damage to a battery module is reduced.

The gist of the invention is that the establishment of the safe state according to the characterizing features of the independent claims is performed in dependence on a characteristic that suggests an internal termination of the battery module.

The background of the invention is to increase the safety in handling battery modules and to reduce the likelihood of damaging a battery module and / or to reduce the impact of defective battery modules on the environment. A successful execution of the safe state of the battery module in response to a characteristic that suggests an internal end of the battery module leads to safe operation of the battery module in the event of an internal end of the battery module and to the transfer of the battery module in a safe state, thereby any Dangers that can be caused by an internal termination of the battery module are avoided as far as possible.

According to the invention, a controller for an intrinsically safe battery module is also provided. The controller is suitable for establishing a safe state of the battery module, wherein the current state of the battery module is continuously checked and evaluated, and the safe state of the battery module to be created is such a state in which effects of a defective battery module are reduced and / or the probability of damage to a battery module is reduced, wherein means are provided for bringing about the safe state, in particular as a function of a characteristic which suggests an internal termination of the battery module.

Further, an intrinsically safe battery module is provided according to the invention, wherein the intrinsically safe battery module can be controlled.

Further advantageous embodiments of the present invention are the subject of the dependent claims.

According to an advantageous embodiment of the invention, the parameter indicative of an internal short circuit of the battery module is a temporal change of a quiescent voltage between the terminals of the battery module. The quiescent voltage considered is the quiescent voltage between the terminals of the battery module in a phase in which the battery module is not beschlagt with charging or discharging. Occurs in a battery module within such a phase, a self-discharge, this self-discharge can be detected by an untypical change in the rest voltage. For functioning lithium-ion battery cells, the typical change in the quiescent voltage is on the order of 1% to 3% of the quiescent voltage per month.

The rest voltage, as well as the time course of the rest voltage, represent physical state variables of the battery module. The use of these state variables leads to the advantage of being able to determine them precisely on the basis of physical parameters and to be able to indicate them quantitatively.

In accordance with another advantageous embodiment of the invention, the parameter indicative of an internal short circuit of the battery module is determined on the basis of other information, in particular information from vehicle information systems.

The use in particular of information from vehicle information systems means that it is possible to fall back on an already existing sensor system for the determination of current and voltage as well as the temporal courses of current and voltage. This recourse leads to the advantage of at least supplementing or checking state variables which have been determined by means of a sensor system provided specifically for the realization of an intrinsically safe battery module. The current is a current flowing through the electrochemical part of the battery module; the voltage is a voltage applied to the terminals of the battery module.

According to a further preferred embodiment of the invention, to achieve the safe state of the battery module, a comparison of the characteristic, which can be concluded that an internal short circuit of the battery module, completed with a threshold value. Depending on the comparison with the threshold and depending on the state of charge of the battery module and / or the pressure inside the battery module and / or the temperature inside the battery module is an actuators (A1, A2), in particular a device for laying a current bypass or a Discharge device or a quick discharge device controlled, so that the battery module is not charged further or as soon as possible and largely discharged.

According to an advantageous embodiment of the invention, in the case of a low state of charge of the battery module, for example, at a state of charge below 40% to 80% of the regular state of charge, a discharging device is activated and the battery module as a function of the temperature of the battery module and / or the time course of the temperature of the battery module. In the case of a high state of charge, for example, in a state of charge between 80% to 100% of the regular state of charge, and a regular pressure inside the at least one battery cell of the battery module, the discharge device is also activated and the battery module depending on the temperature of the battery module and / or the time course of the temperature of the battery module discharged. In the case of a high state of charge, for example, in a state of charge between 80% to 100% of the regular state of charge, and a high pressure inside the at least one battery cell, however, a fast discharge is activated and the battery module depending on the temperature of the battery module and / or the Over time, the temperature of the battery module discharged. An exemplary threshold for excessive pressure inside the battery module can be between 2 bar and 8 bar, in particular between 3 bar and 7 bar.

The reason for the procedure modified in the case of a high pressure inside the battery module is the fact that, for example by means of a temperature sensor, no appreciable increase in the temperature in the cells of the battery module can be detected yet. However, since the increased pressure inside the battery module can indicate that electrolyte decomposition takes place as a result of local heating of a cell, the battery module must be converted into an energetically more favorable state as quickly as possible. The fastest possible transfer to the energetically favorable state is done by means of a discharge of the battery module.

According to a further advantageous embodiment of the invention, if the battery module is almost completely discharged, the discharge device is deactivated and / or the quick discharge device is deactivated after the discharge; the power bypass remains activated.

In accordance with a further advantageous embodiment of the invention, at least one sensor system (S) for detecting physical variables of the battery module is provided for the intrinsically safe battery module for determining the current state of the battery module.

Advantageously, at least the method or the device or the control described above or an intrinsically safe battery module is used at least in vehicle technology or in power engineering.

Brief description of the drawings

In the following section, the invention will be explained with reference to embodiments, from which further inventive features may arise, but to which the invention is not limited in scope. The embodiments are shown in the drawings.

It shows:

1 a schematic representation of an intrinsically safe battery module;

2 a schematic representation of the method for increasing the safety when using intrinsically safe battery modules as a function of a characteristic that suggests an internal end of the battery module, and

3 a basic circuit diagram of an intrinsically safe battery module, which leads to the achievement of a safe state of the battery module as a function of a characteristic that on an internal battery Close the battery module close, is suitable.

Embodiments of the invention

In 1 an intrinsically safe battery module EB is shown schematically. In the case of an intrinsically safe battery module EB, the current state of the battery module is continuously checked and evaluated and a safe state of the battery module is brought about. The safe state of the battery module to be brought about is one in which the effects of a defective battery module are reduced and / or the likelihood of damage to a battery module is reduced. For this purpose, the intrinsically safe battery module EB has, for example, a suitable sensor and actuator concept for realizing intrinsic safety.

The intrinsically safe battery module EB contains at least one cell module Z, which contains at least one battery cell BZ. The at least one battery cell BZ is composed of mechanical components and at least one electrochemical component. The electrochemical component is also referred to as the chemistry system of the intrinsically safe battery module EB. By way of example, the at least one battery cell BZ is a lithium-ion battery cell.

Preferably, a sensor S is further included, with which at least the voltage of the intrinsically safe battery module EB or the current with which the intrinsically safe battery module EB can be discharged or loaded, can be determined. Furthermore, at least one component BEP for battery state detection or for prediction of battery states of the intrinsically safe battery module EB or for the detection or prediction of battery state variables of the intrinsically safe battery module EB is preferably included. Preferably, an actuator A1 is included for establishing a safe state of the intrinsically safe battery module EB; with the actuator A1 preferably at least one unrepresented current bypass between electrical connections of the intrinsically safe battery module EB connected or unloading device, not shown, in particular a Discharge Device, or a fast discharge device, not shown, in particular an Ultrafast Discharge Device, in the field of intrinsically safe battery module EB for use to be brought. For the purpose of the application, the discharge device or the quick discharge device is electrically connected to the terminals of the intrinsically safe battery module EB.

If the current bypass is connected between the electrical connections of the intrinsically safe battery module EB, an electric current can flow between the electrical connections of the intrinsically safe battery module EB without this current flowing through the electrochemical component of the at least one battery cell BZ of the intrinsically safe battery module EB. The current bypass can also be connected between the terminals of the at least one battery cell BZ.

Preferably, an actuator A2 is further included; With the actuator A2, the output voltage of the intrinsically safe battery module EB can at least be controlled or varied in height.

In 2 a method for increasing the safety when using intrinsically safe battery modules EB is shown schematically. By process step 11 the procedure is initiated. In a subsequent threshold comparison step 22 It is checked whether a parameter reaches or exceeds a threshold value.

The characteristic value and the threshold value are preferably a pressure in the interior of the intrinsically safe battery module EB or a temporal change of a pressure in the interior of the intrinsically safe battery module EB. An exemplary threshold for excessive pressure inside the battery module can be between 2 bar and 8 bar, in particular between 3 bar and 7 bar. If the parameter neither reaches nor exceeds the threshold, then the threshold comparison step 22 repeated.

When the parameter reaches or exceeds the threshold, it becomes in a subsequent stream bypass step 33 a power bypass in the range of the intrinsically safe battery module EB is activated so that the intrinsically safe battery module EB is not discharged uncontrollably. Subsequently, in pressure test step 44 Checked if the pressure inside the intrinsically safe battery module EB is too high. If the pressure inside the intrinsically safe battery module EB is too high, it will go into the fast discharge device step 55 a fast discharge device, in particular an Ultrafast Discharge Device, activated, so that the intrinsically safe battery module EB is discharged as far as possible and as quickly as possible. In the following final step 66 the procedure is completed.

On the other hand, if the pressure inside the intrinsically safe battery module EB is not too high, it will be in the discharging step 77 a discharge device, in particular a Discharge Device, activated, so that the intrinsically safe battery module EB is largely discharged. In the subsequent final step 66 the procedure is completed.

Preferably, all state variables of the intrinsically safe battery module EB listed in the method steps described above are determined, for example, with the aid of the sensor system S. The examination and evaluation of the state variables is preferably carried out by the component BEP for battery state detection. The actuator processes carried out in the method steps are carried out, for example, by means of the actuators A1, A2.

As an alternative to the sensor system S, which is part of the intrinsically safe battery module EB, further sensors existing outside the intrinsically safe battery module EB can be used to determine state variables of the intrinsically safe battery module EB. For example, these may be sensors that belong to the equipment of a vehicle in which the intrinsically safe battery module EB is used. By way of example, these may be sensors for determining electrical variables such as current or voltage.

The use of an intrinsically safe battery module EB is possible in vehicle technology and also in power engineering.

In 3 a basic circuit diagram of an intrinsically safe battery module EB is shown.

The basic circuit diagram shows a cell module Z, a cell monitoring electronics CSC and a module monitoring electronics MSC.

The cell module Z contains at least one battery cell BZ. By way of example, the at least one battery cell BZ is a lithium-ion battery cell.

The cell monitoring electronics CSC contains the in the description too 1 said sensor S for detecting a state of the at least one battery cell BZ. The cell monitoring electronics CSC serves to monitor the at least one battery cell BZ within the cell module Z.

The module monitoring electronics MSC communicates with the cell monitoring electronics CSC. The communication between cell monitoring electronics CSC and module monitoring electronics MSC can be wireless or wired via a communication line KL. As part of the communication between the module monitoring electronics MSC and the cell monitoring electronics CSC data is transmitted via at least one battery cell BZ. Furthermore, the module monitoring electronics MSC has the sensors S for monitoring the cell module Z.

Depending on the state of the at least one battery cell BZ or of the cell module Z, the module monitoring electronics MSC can act. For this purpose, the module monitoring electronics MSC contains at least two semiconductor valves HV1 and HV2 which can be switched on and off and two diodes D1 and D2. Depending on a turn-off semiconductor valve and a diode form a half-bridge arrangement. An upper half-bridge arrangement comprising HV1 and D1 is denoted H _o in the drawing, a lower half-bridge arrangement containing HV2 and D2 is H _u . The upper half-bridge arrangement and the lower half-bridge arrangement form a controllable power switch L.

In the normal case, for example, in the regular operating state of an intrinsically safe battery module EB, the upper half-bridge arrangement H _{o is} turned on, the lower half-bridge arrangement H _u is turned off. In this state, the cell monitoring electronics CSC carries out a charge equalization between at least two battery cells BZ.

If the module monitoring electronics MSC detects a current bypass in the region of the intrinsically safe battery module EB by means of a parameter indicative of an internal short circuit of the intrinsically safe battery module EB, the upper half-bridge arrangement H _{o is switched} off and the lower half-bridge arrangement H _{u is} switched on. The current flowing through the cell module Z then flows through the lower half-bridge arrangement H _u .

If the module monitoring electronics MSC recognizes an internal short-circuit of the intrinsically safe battery module EB that an unloading device or a fast discharge device in the area of the intrinsically safe battery module EB must be applied, the upper half-bridge arrangement H _o off and the lower half-bridge arrangement H _u switched on. The current flowing through the cell module Z then flows through the lower half-bridge arrangement H _u .

In addition to the in 3 shown monitoring the battery cells by means of cell monitoring electronics, a battery cell's own monitoring by one, the at least one battery cell BZ associated cell monitoring electronics CSC is possible. For this purpose, each battery cell BZ is assigned its own sub-cell monitoring electronics. These sub cell monitoring electronics communicate with a main cell monitoring electronics. The main cell monitoring electronics communicates with the module monitoring electronics MSC, which acts inter alia in dependence on the information communicated to the main cell monitoring electronics.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011113798 A1 [0002]

Claims (11)

A method for establishing a safe state of a battery module, wherein the current state of the battery module is continuously tested and evaluated and the safe state of the battery module to be brought about is such a state in which effects of a defective battery module are reduced and / or the probability of Damage to the battery module is reduced, characterized in that the establishment of the safe state in dependence on a characteristic that is indicative of an internal short circuit of the battery module is completed. A method according to claim 1, characterized in that it is the characteristic which can be concluded that an internal short circuit of the battery module is a temporal change of the rest voltage between the terminals of the battery module. A method according to claim 2, characterized in that the characteristic which is indicative of an internal short circuit of the battery module is determined on the basis of other information, in particular information from vehicle information systems. Method according to one of the preceding claims, characterized in that, in order to bring about the safe state of the battery module, a comparison of the parameter is performed with a threshold and depending on the state of charge of the battery module and / or the pressure inside the battery module and / or the temperature in Inside the battery module in the event that the parameter reaches or exceeds the threshold - a power bypass is permanently activated and / or the battery module is not charged and / or the battery module as a function of the state of charge as soon as possible and completely discharged. A method according to claim 4, characterized in that, in the case of a low state of charge, for example, in a state of charge under 40% to 80% of the regular state of charge of the battery module activates a discharging device and the battery module as a function of the temperature of the battery module and / or the temporal History of the temperature of the battery module is discharged and in the case of a high state of charge, for example, at a state of charge between 80% to 100% of the regular state of charge, and a regular pressure inside the at least one battery cell of the battery module, the discharger is activated and the battery module in dependence Temperature of the battery module and / or the time course of the temperature of the battery module is discharged and in the case of a high state of charge, for example, in a state of charge between 80% to 100% of the regular state of charge, and a high pressure inside the at least one Batteriez elle, wherein an exemplary threshold for excessive pressure in the interior of the battery module between 2 bar and 8 bar, in particular between 3 bar and 7 bar may be a quick discharge enabled and the battery module as a function of the temperature of the battery module and / or the time course the temperature of the battery module is discharged. A method according to claim 4 or 5, characterized in that, if the battery module is almost completely discharged, the unloading device is deactivated and / or the quick discharge device is deactivated and / or the current bypass remains activated. Control for an intrinsically safe battery module (EB), suitable for establishing a safe state of the battery module, wherein the current state of the battery module is continuously tested and evaluated and the safe state of the battery module to be brought about is such a state in which the effects of a defective one Battery module can be reduced and / or the likelihood of damage to the battery module is reduced, characterized in that means are provided for bringing about the safe state depending on a characteristic indicative of an internal short circuit of the battery module, in particular by performing a method according to one of the preceding claims. Intrinsically safe battery module (EB), characterized in that a controller is provided according to claim 7. Intrinsically safe battery module (EB) according to claim 8, characterized in that for determining the current state of the battery module at least one sensor (S) for detecting physical quantities of the battery module, is provided. Intrinsically safe battery module (EB) according to claim 8, characterized in that for bringing about the safe state of the battery module at least one device for laying a current bypass and a discharging device, in particular a Discharge Device, and a Quick discharge device, in particular an Ultrafast Discharge Device, are provided. Use of a method according to one of claims 1 to 5 and / or a device according to one of claims 7 to 10 and / or a controller according to claim 7 and / or an intrinsically safe battery module (EB) according to one of claims 8 to 10 in the vehicle technology and / or in power engineering.

Images