The present invention relates to a battery and more particularly to a battery control method.
Batteries, in particular batteries which have a multiplicity of cell modules, are monitored with regard to electrical and physical states. This also includes monitoring thermal states, in particular detecting so-called thermal breakdown. To detect a thermal event (thermal runaway) in one or more cells of a battery or of a battery system, the pressure or the pressure curve is evaluated, the pressure increase as a result of a pressure relief valve being opened, as a result of which in the interior of a battery increases significantly in a short time. This pressure measurement is performed, for example, by a pressure sensor which can be arranged on the main board, for example, as part of the battery management system (BMS). Such a “thermal event” (thermal runaway) is a state in which the heating increases independently due to chemical processes without any further external influence, such as, for example, the current load, and wherein the chemical process is simultaneously accelerated.
Such an arrangement is shown by DE 10 2018 210 975 B4, for example, in which a thermal event is detected by a pressure sensor arranged on a main board of the battery control unit.
Accommodating the pressure sensor on the main board is disadvantageous because this main board has to be physically enlarged further for this purpose, thereby making it difficult to accommodate it in the battery and further complicating the verification of the data from the pressure sensor on the main board according to the ASIL standard.
It is the object of the present invention to propose improved pressure detection.
This object is achieved according to the invention by a battery according to the features of claim 1 and a method according to the features of claim 9. Advantageous configurations are specified in the respective, associated dependent claims.
The object is accordingly achieved by a battery which is in the form of a high-voltage battery (HV battery) and comprises the following battery elements:
In this case, a cell measurement board means a board which is arranged directly on or in a cell module and comprises microelectronic parts and components which are primarily used to control and evaluate the respective cell module and are connected to the main control unit and actuated by the latter. The secondary board is a further central board which is separate from the main control unit and/or the main board and which is likewise connected to the main control unit.
Instead of the term “switch box” used here, “s-box”, “switch-box” or “BJB” (battery junction box) is often also used. In somewhat rarer cases, the designation “e-box” may also be used for the same part.
In this case, “connected” is not to be understood in a restrictive sense and means both one or more connections for the voltage supply and current supply and also for the data-carrying communication. The communication can in particular be in the form of one of the customary bus technologies or serial interfaces, such as isoSPI, by way of separate individual cables or modulated on one or more current-carrying individual cables.
It is advantageous here if a pressure sensor is in each case arranged on a plurality of cell measurement boards, in particular if a pressure sensor is provided on each cell measurement board.
The big advantage of this solution is that a thermal event is detected directly in the vicinity of a specific cell module or group of cell modules. In particular, in the case of the arrangement of a plurality of pressure sensors, the source of the event can be narrowed down on the basis of the order of the detecting pressure sensors.
In an improved embodiment, a temperature sensor is provided on at least one of the cell measurement boards, which temperature sensor is arranged adjacent to the at least one pressure sensor on the same cell measurement board and/or on a cell measurement board of an adjacent cell module.
As a result, it is also possible to detect thermal events quickly and reliably using a small number of pressure and temperature sensors, and to furthermore narrow down these events with regard to the origin, that is to say the defective cell module or a group of cell modules.
In a further embodiment, the at least one pressure sensor is arranged on a central secondary board, wherein the secondary board is attached within the switch box, wherein an improvement to this is that at least one and in particular all the microelectronic high-voltage elements (HV elements) are arranged in the switch box, these elements being arranged either on the secondary board or on their own high-voltage board. The big advantage of transferring the microelectronic HV elements to a central secondary board is that the state detection and evaluation take place in the vicinity of the high-voltage lines (HV+, HV−) and of the cell modules and furthermore the shielding and protection of the data from these HV elements is improved in relation to the other microelectronic elements and parts on the main board and it becomes much easier to comply with the ASIL standard.
Since communication using the ASIL standard is required for the central secondary board in the present case and said communication is used for the pressure signal, advantageously no additional communication interface is necessary.
In this case, HV elements means in particular analog-to-digital converters (ADCs) in the form of galvanically isolated capacitive couplers, inductive couplers or optocouplers for transmitting data from the high-voltage range to a low-voltage range, and voltage measuring elements/chips.
Advantageously, a p secondary processor is arranged on the secondary board and/or the high-voltage board, which p secondary processor is primarily used to process the data and process the micro-parts arranged on the respective board and is connected to the main control unit and in particular the main microprocessor thereof.
Ideally, the battery has an outer battery housing, which is generally closed in a dust-tight and/or vapor-tight manner, and the battery elements are by and large arranged inside this battery housing. In this case, as one embodiment, a battery housing is also to be understood to mean a multi-part housing if the individual housing parts are combined with one another via a connecting channel or connecting space but continue to form a common battery space on the outside. In the present instance, this could be the case if the switch box is flange-mounted or screwed on or to a battery housing and an opening or a channel, which is closed to the atmosphere, is formed between the switch box and the interior of the battery housing. Connecting lines are usually laid in this channel or this opening.
In order to shield the interior of the battery, to shield against electromagnetic interference and in order to protect against soiling, it is advantageous if the switch box has its own box housing, which is at least partly closed, in particular completely closed. For the case in which electronics are installed in the box, it is advantageous if this box has or is formed of a metal housing. Greatly advantageous in this case is the easy handling and the possibility of prefabrication. A switch box consisting of many components can thus be produced externally as one structural unit and be connected to the HV battery in just a few steps to form one unit.
The invention also comprises a method for operating a battery, in particular a HV battery, which comprises a battery management system (BMS) with a main control unit and a main board and has a plurality of cell modules.
The essence of the inventive method is that at least one pressure sensor is provided in order to detect exceeding a thermal threshold value, generally referred to as a thermal event, in the interior of the battery and/or in the region of a cell compartment or the cell modules, which pressure sensor is arranged outside the main board.
Advantageously, the battery, in particular in the form of a HV battery, is provided in the form of a battery according to one of the variant embodiments described above. On the whole, high voltage (HV) in the present case largely means a voltage range from 60 V to 2000 V DC, in particular from 60 V to 1500 V DC, which relates in particular to the power requirements of e-vehicles, such as, for example, electrically driven passenger cars, trucks and buses.
Further details and advantages of the invention will now be explained in more detail on the basis of an exemplary embodiment illustrated in the drawings.
In the drawings:
The HV+ line 40 is routed into the switch box 20 and to the contactor 8 there, which is used to switch the line 40. Similarly, the HV− line 41 is likewise routed into the switch box 20 and to the contactor 9. Furthermore, there is provision for an auxiliary current path 42 on the HV+ line in the switch box 20 in order to operate the contactor 12, which acts as a precharging contactor. Furthermore, there is provision for a current sensor 24 in the switch box 20; other fuses, resistors or further components are not illustrated. The main board 11 is connected to the switch box 20 or individual components and parts in the switch box 20 via the line connection 44, this not having been distinguished in detail in the present case. The main board 11 comprises a plurality of microelectronic/electronic elements 5.1, 5.2, 5.3 and a main microprocessor 4. In the exemplary embodiment shown, the pressure sensor 6 according to the invention is arranged in the switch box 20 and connected to the main control unit 10, or the main board 11 thereof, via a separate line connection 45.
A temperature sensor 7 is mounted on the cell measurement board 32.2 and therefore in the immediate vicinity of the pressure sensor 6. In this case, the temperature sensor 7 is applied directly to the cell measurement board 32.2 as a surface-mounted device (SMD component). When the pressure sensor 6 detects a rapid increase in pressure, it is possible to ascertain whether the thermal event is originating from the level 35 or, because the temperature sensor 7 is not reporting increased values or is reporting them very late, the thermal event has to be originating from the level 36 of the cell compartment 30.
In the embodiment according to
The current sensor 24 on the HV− line is connected via its own line 47 to the secondary board 21 and/or the p secondary processor 23. This secondary board 21 itself, as a subordinate element in the BMS, is connected on the one hand to the main board 11 via the line 44 and to the components of the cell compartment via the line 46. All the components which monitor and process the HV functions are thus combined in a separate space, namely the switch box 20, and can be shielded and protected in an appropriate manner.
In the exemplary embodiment according to
Both alternatives allow a logical evaluation of whether a thermal event is originating from the cell module itself, an immediately adjacent cell module or a remotely arranged cell module.
Number | Date | Country | Kind |
---|---|---|---|
10 2021 114 090.0 | Jun 2021 | DE | national |
This application is a 35 U.S.C. § 371 National Stage Entry of International Application No. PCT/EP2022/064910 filed Jun. 1, 2022, which claims the priority benefit of German Patent Application Serial Number DE 10 2021 114 090.0 filed Jun. 1, 2021, all of which are incorporated herein by reference in their entirety for all purposes.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2022/064910 | 6/1/2022 | WO |