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

Abstract

Method for monitoring a battery pack, wherein the battery pack comprises at least one electrochemical cell, characterized in that The battery pack is detected and recorded when it is opened, the battery pack having a locking mechanism, and the locking mechanism is unlocked depending on the result of an authorization query.

Description

[0001] The present invention relates to a method for monitoring a battery pack, a battery with a monitoring module and a motor vehicle with a corresponding battery, which can be used in particular to check warranty claims that may have been voided by unauthorized opening of the battery pack. State of the art

[0002] The battery is one of the most important and expensive components of an electric or hybrid vehicle. For this reason, most original equipment manufacturers (OEMs) require battery pack suppliers to provide a warranty for their batteries. In addition to OEM requirements, such warranties are also mandated by legislation for zero-emission vehicles (ZEVs). The warranty period is typically between five and ten years. Another important factor is cost. Battery packs cost several thousand euros, and replacing a used battery with a new one when it is returned by the OEM to the supplier is extremely expensive.

[0003] Since the warranty period and the cost of batteries are not comparable to those of other vehicle parts, it is important for battery suppliers to ensure, through special measures, that the battery has not been handled (improperly) by an unauthorized person.

[0004] Inappropriate treatments can be caused, for example, by... - due to incorrect charging / discharging of the battery and / or - on replacing a faultless battery with a faulty or old battery.

[0005] According to current technology, improper charging / discharging can detect incorrect handling by using a battery data recording device. This device records the current supplied to and drawn from the battery during charging and discharging and stores the state of charge in a storage medium, such as an electrically erasable programmable read-only memory (EEPROM) or a flash EEPROM. These records can then be evaluated later, off-board, for analysis or to verify warranty claims.

[0006] A method for identifying a hand-held power tool is known from publication DE 10 2007 007 506 A1. There, it is proposed that, in order to prove whether a damaged tool is an original part, the housing of the hand-held power tool should be manufactured at least partially from a plastic to which an indicator component has been added.

[0007] Document DE 10 2011 002 718 A1 discloses an accumulator with at least one tamper sensor designed to detect abnormal operating parameters of the accumulator, a reservoir containing substances to suppress unwanted chemical reactions in the accumulator, and a control device designed to initiate the release of the substances in the reservoir depending on an output signal from the at least one tamper sensor.

[0008] Document JP 2008 204 878 A discloses a battery and a device for detecting unauthorized opening of the battery.

[0009] Document US 7 084 361 B1 discloses a device comprising a connector and a cover to prevent contact with the battery contacts and to de-energize the high-voltage network when necessary.

[0010] No procedure is currently known for proving that a functional battery has been replaced with a faulty or old one. Disclosure of the invention

[0011] A particular advantage of the invention is that unauthorized access to a battery system, especially the replacement of a functional battery with a defective one or the replacement of electrochemical cells within the battery system, can be detected. This is achieved by monitoring battery packs according to the invention, with any opening of the battery pack being detected and recorded. A battery pack comprises at least one electrochemical cell, but preferably a plurality of electrochemical cells, wherein the electrochemical cells are connected in series. In a preferred embodiment of the method according to the invention, at least one opening of the battery pack by unauthorized persons, but preferably every opening, is documented in a non-erasable storage medium.For this purpose, it proves advantageous if at least information about the date and time of the opening event, the mileage at the time of opening, the identifier of the person opening the vehicle, or similar data is captured and recorded. This has the advantage that, with the help of this information, the circumstances relevant to the assessment of warranty claims can be evaluated more precisely. A preferred embodiment of the invention provides for the use of a ring buffer as the storage medium. This optimizes storage utilization, since only a storage space of a predetermined size is used, as older entries are "pushed out" of the memory when a new entry is stored and the memory is full. Preferably, at least the detection and / or recording of the data is performed automatically.

[0012] The battery pack advantageously has a locking mechanism. Such a locking mechanism prevents the battery pack from being opened by unauthorized persons or from being opened unnoticed by unauthorized persons. It is advantageous if the locking mechanism is designed as a magnetic, preferably electromagnetic, closure.

[0013] A preferred embodiment provides that, to determine whether a person is authorized to open the device, an authorization query is performed before opening. Preferably, the authorization query is performed by the BCU. Particularly preferably, the query takes the form of a dialogue between the person and the BCU, whereby commands from a Unified Diagnostic Service (UDS) are preferably sent at least partially within the dialogue.

[0014] It is also advantageous if the locking mechanism of the battery pack can be locked by an authorized person. Preferably, the authorization check for this is carried out in a manner analogous to the authorization check for opening the battery pack.

[0015] Another preferred embodiment provides that the battery pack can also be opened without authorization. This is particularly advantageous in emergency situations. It proves beneficial if, in predefined cases, the locking mechanism is (automatically) released by the BCU so that the battery pack can be opened without damage. Alternatively or in parallel, it can be provided that the locking mechanism can also be forcibly released without authorization, allowing the battery pack to be opened. For this purpose, for example, it can be provided that a seal or predetermined breaking point is damaged during such forcible opening in order to document the opening. In addition, the opening can also be documented by writing information about the opening event to a preferably non-erasable storage medium, in a manner comparable to the documentation of the opening in the monitoring procedure described above.

[0016] In a preferred embodiment of the invention, monitoring is performed by a battery control unit (BCU). In this case, existing software and hardware can be used, thus minimizing the effort required to implement the invention. It is advantageous if the BCU includes a hardware interlock, such as a high-voltage interlock loop (HVIL), and if the monitoring includes an evaluation of the signals provided by the hardware interlock. However, it can also be advantageous if the monitoring is independent of the BCU. Hardware and / or software components can be provided for this purpose.

[0017] In another preferred embodiment, phases are provided in which the battery control unit is in a sleep mode to minimize energy consumption. However, monitoring remains active even while the battery control unit is in sleep mode. In particular, the HVIL remains active even during the BCU's sleep mode phases.

[0018] Another aspect of the invention relates to a battery with a module for monitoring a battery pack, wherein the module is configured such that a method for monitoring the battery pack is feasible, the battery pack comprising at least one electrochemical cell, and wherein an opening of the battery pack is detected and recorded. Preferably, the battery is a lithium-ion battery or the battery comprises electrochemical cells configured as lithium-ion battery cells.

[0019] Another aspect of the invention relates to a motor vehicle with an electric drive motor for propelling the motor vehicle and a battery connected or connectable to the electric drive motor, as described in the preceding paragraph. However, the battery is not limited to such an application but can also be used in other electrical systems.

[0020] The invention presents a method which ensures that battery packs returned to the supplier by an OEM (after a fault report) have not actually been mishandled by a repair shop, gas station or other unauthorized bodies or persons.

[0021] The invention has the particular advantage that Unlike current technology, the BCU has the capability to determine whether the battery pack has been opened by an unauthorized person. Recording this information enables the OEM to verify warranty claims. - The invention further ensures that no unauthorized person can open the battery pack.

[0022] Advantageous embodiments of the invention are specified in the dependent claims and described in the description. Drawings

[0023] Exemplary embodiments of the invention are explained in more detail with reference to the drawings and the following description. The drawings show: Fig. 1. An illustration of an exemplary memory management system for saving information documenting an opening, and Fig. 2. An illustration of a dialogue of an exemplary authorization query. Embodiments of the invention

[0024] The invention is described below with reference to two exemplary embodiments. An important aspect of the invention is to equip a battery pack with a monitoring mechanism. In a further embodiment, the battery pack is additionally equipped with a locking mechanism. The monitoring and locking mechanisms can be provided individually or together in combination. A preferred embodiment provides for the use of the BCU's functionality to control the monitoring and / or locking mechanism. Monitoring mechanism:

[0025] When used as a monitoring device, the BCU monitors for opening of the battery pack. This is achieved by utilizing an existing hardware interlock feature of the battery management system (BMS). A high-voltage monitoring circuit (HVIL) can be used as such a hardware interlock. A hardware interlock detects unconnected, isolated contacts to prevent people from coming into contact with high-voltage wires. This hardware interlock includes a PWM signal generator (PWM = pulse-width modulation) of the BMS, which applies its signals to a series of loop contacts. If the high-voltage connection is not connected, the circuit is broken. Such a broken circuit is detected by the BMS hardware interlock, which then no longer receives a PWM signal. In this case, the BMS immediately disconnects all contacts.Furthermore, all other active components capable of supplying high voltage to the bus are also prevented from doing so. Thus, the hardware interlock ensures that the battery pack cannot be opened without the BCU being notified. To prevent the BCU software from being constantly active, a sleep mode can be implemented for the BCU when the ignition is off. The BCU software can then be reactivated by an HVIL event. Such a sleep mode helps to conserve energy.

[0026] This mechanism allows the BCU to detect and record every time the battery pack is opened. The BCU monitors the signals from the hardware interlock (HVIL signals) and receives a pulse when the battery pack is opened. After receiving the pulse, the BCU stores data describing the event, such as date (102), time (104), mileage (106), a tester ID (108), or similar information, in its non-erasable memory. Ideally, this data should not be erasable, even by an OEM tester.

[0027] In the exemplary embodiment, the BCU ensures that every "Open Battery Pack" event is detected and the corresponding data is stored in the non-erasable memory. To optimize memory usage, the BCU provides a ring buffer 100 of a predefined length. When new entries are stored in the ring buffer 100, the already stored entries are shifted forward, as described in Fig. This is illustrated by the reference symbol 110. When the ring buffer 100 is full, the older entries are deleted (see below). Fig. 1).

[0028] If an OEM sends a defective battery pack to the supplier, the supplier can check whether the battery pack has been opened. If it has been opened, the date (102) and time (104) of the opening can be read from the BCU. Using this information, the supplier can determine whether the warranty claims are valid.

[0029] Since it is possible that the BCU is in sleep mode when the battery pack is opened by someone, a preferred embodiment provides that a wake-up signal is sent when the battery pack is opened. Locking and monitoring mechanism:

[0030] Although the monitoring mechanism described in the preceding section ensures that the BCU 202 always detects when the battery pack has been opened and documents these events, this procedure cannot prevent the battery pack from being opened by unauthorized persons.

[0031] To prevent such unauthorized opening, a second embodiment provides a lock for the battery pack. The lock prevents the battery pack from being opened without sufficient authentication. The lock is controlled and monitored by the BCU 202. Opening is therefore only permitted for authorized persons, such as an authorized inspector 204.

[0032] To open the battery pack, the user sends a sequence of commands, such as those from a unified diagnostic service, to the BCU 202. Based on these commands, the BCU 202 determines the user's authorization and, depending on this decision, grants access and releases the battery pack's lock. Preferably, this lock is magnetic.

[0033] Based on Fig. Section 2 describes an example command sequence: The inspector 204 sends the UDS command 206 “Security access - Request seed” to the BCU 202.

[0034] The BCU 202 responds by sending a seed (208).

[0035] The inspector 204 uses this seed and, in step 210, calculates a key using a security algorithm. The key generated in this way is sent to the BCU 202 with the UDS command 212 "Security access - Send key".

[0036] The BCU 202 uses the same seed and authenticates the key in step 214. For this, the BCU 202 generates the verification key using an algorithm within its memory. The BCU 202 then compares the key received from the verifier 204 with the verification key. If the keys match, the BCU 202 grants the verifier 204 permission to enter further commands by sending message 216. Message 216, which the BCU 202 sends after authentication, can also contain a message indicating that access is denied if authentication fails.

[0037] The tester 204 sends various pieces of information 218, which identify it, to the BCU 202, such as a tester ID 108, a tester type or the like. In step 220, the BCU 202 stores these pieces of information 218 in a non-erasable memory.

[0038] The BCU 202 signals to the tester 204 by sending a message 222 that the data 218 has been successfully saved.

[0039] The tester 204 then sends the UDS command 224 to open the battery pack to the BCU 202 in order to open the magnetic closure by sending the UDS command 224 “Routine Control”.

[0040] Upon receiving this UDS command 224, the BCU 202 releases the magnetic lock in step 226 and signals this to the tester 204 by sending a message 228.

[0041] An analog command sequence can be used to lock the magnetic closure.

[0042] For safety reasons, one exemplary embodiment provides that the BCU 202 opens the closure without requiring a checker 204 if the BCU 202 detects a hazardous situation. Another exemplary embodiment further provides that the magnetic closure can also be opened without authorization, for example, by applying mechanical force. With a magnetic closure, this can be achieved by selecting the magnetic force accordingly. Such a closure that can be opened by force would make unauthorized opening obvious without preventing opening in every case, which is particularly important in hazardous situations.

[0043] The invention ensures that the battery pack cannot be opened without proven authorization. Furthermore, the BCU 202 records whether the battery pack has been opened, and in cases of opening, data such as time 104, date 102, and / or mileage 106 are stored. Information about persons authorized to open the battery pack is also stored. This procedure enables the OEM to assess warranty claims.

[0044] The invention is not limited in its embodiment to the preferred embodiments specified above. Rather, a number of variants are conceivable that make use of the inventive method, the inventive battery, and the inventive motor vehicle, even in fundamentally different designs.

Claims

[1] Method for monitoring a battery pack, wherein the battery pack comprises at least one electrochemical cell, characterized by , that The battery pack is detected and recorded when it is opened, the battery pack having a locking mechanism, and the locking mechanism being unlocked depending on the result of an authorization query. [2] Method according to claim 1, wherein the detection is carried out by a battery control unit (202). [3] Method according to claim 1 or 2, wherein a signal from a hardware interlock is monitored to detect the opening. [4] Method according to one of the preceding claims, wherein, upon detection of an opening of the battery pack, information about the event of the opening is stored in a storage medium. [5] Method according to claim 4, wherein the storage medium is a ring buffer (100). [6] Method according to any one of claims 3 to 5 above, wherein phases are provided in which the battery control unit (202) is in a sleep mode, and wherein the hardware switching lock is active during the sleep mode phases. [7] Battery with a module for monitoring a battery pack, wherein the module is configured such that a method for monitoring a battery pack according to any one of claims 1 to 6 is feasible. [8] Motor vehicle comprising an electric drive motor for propelling the motor vehicle and a battery connected or connectable to the electric drive motor according to claim 7.

Images