Method for monitoring a battery pack, battery with a monitoring module and a motor vehicle with a corresponding battery

Abstract

A method is used for monitoring a battery pack to check claims under guarantee that could possibly be invalid due to incorrect opening of the battery pack. The battery pack includes at least one electrochemical cell. When the battery pack is monitored, whether the battery pack has been opened is detected and any details relating to an event of opening are recorded in a non-erasable storage medium.

Claims

1. A method for monitoring a battery pack having at least one electrochemical cell, the method comprising: detecting and recording an opening of the battery pack, wherein detecting the opening includes monitoring a signal from a hardware switching inhibitor using a battery control unit, and wherein the hardware switching inhibitor comprises a high voltage interlock loop, and wherein the battery pack has a locking mechanism which is controlled by the battery control unit, and wherein the battery control unit is configured to unlock the locking mechanism based on a result of an authorization check.

2. The method as claimed in claim 1, further comprising: storing details about the opening in a storage medium.

3. The method as claimed in claim 2, wherein the storage medium is a ring memory.

4. The method as claimed in claim 1, wherein: the battery control unit is in a quiescent mode during phases, and the hardware switching inhibitor is active during the phases.

5. A battery, comprising: a battery pack having at least one electrochemical cell; a high voltage interlock loop that generates a signal indicative of a state of a high voltage connection of the at least one electrochemical cell; a module configured to monitor the signal a battery pack having at least one electrochemical cell; and a battery control unit, wherein the module is configured such that an opening of the battery pack is detected and recorded in memory when the signal indicates that the high voltage connection is not connected detectable and recordable, wherein the battery pack has a locking mechanism which is controlled by the battery control unit, and wherein the battery control unit is configured to unlock the locking mechanism based on a result of an authorization check.

6. A motor vehicle, comprising: an electric drive motor configured to drive the motor vehicle; and a battery connected to or connectable to the electric drive motor, the battery including: a battery pack having at least one electrochemical cell; a high voltage interlock loop that generates a signal indicative of a state of a high voltage connection of the at least one electrochemical cell; a module configured to monitor the signal a battery pack having at least one electrochemical cell; and a battery control unit, wherein the module is configured such that an opening of the battery pack is detected and recorded in memory when the signal indicates that the high voltage connection is not connected detectable and recordable, wherein the battery pack has a locking mechanism which is controlled by the battery control unit, and wherein the battery control unit is configured to unlock the locking mechanism based on a result of an authorization check.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the disclosure are explained in more detail with reference to the drawings and the description that follows. In the drawings:

(2) FIG. 1 shows an illustration of exemplary memory management for storing details that document opening, and

(3) FIG. 2 shows an illustration of a dialog from an exemplary authorization check.

(4) FIG. 3 is a block diagram that schematically depicts components of the battery management system including the battery pack, high voltage interlock loop, battery control unit and memory.

DETAILED DESCRIPTION

(5) The disclosure is described below with reference to two exemplary embodiments. An important aspect of the disclosure is that of equipping a battery pack with a monitoring mechanism. In addition, a further embodiment has provision for the battery pack to be equipped with a closure mechanism. In this case, the monitoring and closure mechanisms may each be provided alone or jointly in combination. One preferred embodiment in this case provides for the scope of functions of the BCU to be used for controlling the monitoring and/or closure mechanism.

(6) Monitoring Mechanism:

(7) Referring to FIG. 3, when used as a monitoring device, the BCU 202 monitors opening of the battery pack 200. This is achieved by virtue of an already present hardware switching inhibitor of the battery management system (BMS) being used. By way of example, a high voltage monitoring loop (HVIL) 201 can be used as such a hardware switching inhibitor. A hardware switching inhibitor allows the ascertainment of unconnected standalone contacts in order to prevent people from coming into contact with lines carrying high voltage. This hardware switching inhibitor comprises a PWM (pulse width modulation) signal generator of the BMS, which PWM signal generator applies its signals to a series of loop contacts. When the high voltage connection is not connected, the chain is interrupted. An interrupted chain of this kind is recognized by the hardware switching inhibitor of the BMS, which in this case no longer receives a PWM signal. In this case, the BMS immediately isolates all contacts. Furthermore, all other active components that are capable of emitting high voltage to the bus are likewise prevented from outputting high voltage to the bus. Hence, the hardware switching inhibitor ensures that the battery pack cannot be opened without the BCU 202 being informed of the opening of the battery pack. In order to prevent the BCU software from being constantly active, a quiescent mode can be provided for the BCU 202 when the ignition is switched off. The BCU software can be woken again by an HVIL event. Such a quiescent mode helps to save energy.

(8) This mechanism allows the BCU to capture and record any opening of the battery pack. The BCU monitors the signals from the hardware switching inhibitor (HVIL signals) and is thus provided with a pulse when the battery pack is opened. After it has received the pulse, the BCU stores data that describe the event, such as date 102, time 104, odometer reading 106, an examiner identifier 108 or the like, in its inerasable memory. Preferably, these data should not be able to be erased, not even by an OEM examiner.

(9) In the exemplary embodiment, the BCU ensures that every open battery pack event is detected and the relevant data are stored in the inerasable memory. In order to optimize memory use, the BCU provides a ring memory 100 of prescribed length. When new entries are stored in the ring memory 100, the entries that are already stored are shifted onward, as illustrated in FIG. 1 by the reference symbol 110. When the ring memory 100 is full, the older entries are erased (cf. FIG. 1).

(10) When an OEM now sends a defective battery pack to the supplier, the supplier can check whether or not the battery pack has been opened by anyone. If the battery pack has been opened, the date 102 and the time 104 of the opening can be read from the BCU. These details can be used by the supplier to establish whether the guarantee claims are legitimate.

(11) Since it may occur that the BCU is in the quiescent mode when the battery pack is opened by someone, one preferred embodiment provides for opening to prompt a wake signal to be sent.

(12) Closure and Monitoring Mechanism:

(13) Although the monitoring mechanism described in the preceding paragraph ensures that the BCU 202 always recognizes when the battery pack has been opened, and documents these events, this method cannot be used to prevent the battery pack from being opened by unauthorized persons.

(14) In order to prevent such unauthorized opening, a second exemplary embodiment has provision for closure for the battery pack. The closure prevents the battery pack from being able to be opened without adequate authentication. The closure is controlled and monitored by the BCU 202. Accordingly, opening is allowed only for authorized persons, such as an authorized examiner 204.

(15) To allow opening, the relevant person sends a sequence of commands, such as commands from a unified diagnostic service, to the BCU 202. Using these commands, the BCU 202 makes a decision about the authorization of the person and takes this decision as a basis for allowing access and disengages the closure of the battery pack. Preferably, this is a magnetic closure.

(16) An exemplary command sequence is described with reference to FIG. 2:

(17) The examiner 204 sends the UDS command 206 Security accessRequest seed to the BCU 202.

(18) The BCU 202 responds by sending 208 a seed.

(19) The examiner 204 uses this seed and calculates a key in step 210 by using a security algorithm. The key generated in this manner is sent to the BCU 202 with the UDS command 212 Security accessSend key.

(20) The BCU 202 uses the same seed and authenticates the key in step 214. For this the BCU 202 generates the check key with an algorithm within the memory. Next, the BCU 202 compares the key received from the examiner 204 with the check key. If the keys match the BCU 202 sends a message 216 in order to provide the examiner 204 with the authorization to input further commands. In the event of failed authentication, the message 216 that the BCU 202 sends after the authentication may also contain notification that access is denied.

(21) The examiner 204 sends various details 218 identifying him to the BCU 202, such as an examiner identifier 108, an examiner type or the like. In step 220 the BCU 202 stores these details 218 in an inerasable memory.

(22) The BCU 202 sends a report 222 in order to signal the successful storage of the details 218 to the examiner 204.

(23) Next, the examiner 204 sends the UDS command 224 for opening the battery pack to the BCU 202 in order to open the magnetic closure by sending the UDS command 224 Routine Control.

(24) Following receipt of this UDS command 224, the BCU 202 disengages the magnetic closure in step 226 and signals this to the examiner 204 by sending a report 228.

(25) A similar command sequence can be used in order to lock the magnetic closure.

(26) For security reasons, one exemplary embodiment provides for the BCU 202 to open the closure without any request from an examiner 204 when the BCU 202 establishes a hazard situation. In another exemplary embodiment, provision is also made for the magnetic closure to be able to be opened even without authorization, for example by using mechanical force. In the case of a magnetic closure, this could be achieved by choosing the magnet force accordingly. Such a closure that can be opened by force would render unauthorized opening apparent without preventing opening in any case, which is of particular importance for hazard situations.

(27) The use of the disclosure ensures that the battery pack cannot be opened without authorization being proved. Furthermore, the BCU 202 records whether the battery pack has been opened, and details about time 104, date 102 and/or odometer reading 106 are stored in the cases of opening. In addition, information about persons who open the battery pack with authorization is stored. This approach allows the guarantee claims of an OEM to be rated.

(28) The form of implementation of the disclosure is not limited to the preferred exemplary embodiments indicated above. On the contrary, a number of variants are conceivable that make use of the method according to the disclosure, the battery according to the disclosure and the motor vehicle according to the disclosure even with embodiments of a fundamentally different nature.