Electric vehicle battery system including real time clock

Abstract

The present disclosure relates to an electric vehicle battery system, including: a high voltage system HV system having a plurality of connected rechargeable battery cells; a low voltage system LV system having an operating voltage lower than the operating voltage of the HV system, wherein the LV system supplies power to a battery system manager BSM; a real-time clock RTC configured to provide a system time to the BSM; and a battery disconnect unit BDU, including a BDU relay that can switchably open or close an HV line of the HV system and a BDU control unit adapted to control the BDU relay, wherein the BDU is adapted to exchange data with the BSM via a communication interface. The RTC is integrated into the BDU, and the BDU is adapted so that the RTC is at least temporarily powered by the HV system.

Description

Technical Field

[0001] The present invention relates to an electric vehicle battery system comprising a real-time clock (RTC). The present invention also relates to an electric vehicle comprising the electric vehicle battery system. Background Art

[0002] In recent years, vehicles for the transportation of goods and people have been developed using electricity as a source of motion. Such electric vehicles are cars driven by electric motors using energy stored in rechargeable batteries. Electric vehicles can be powered by batteries alone, or can be in the form of hybrid vehicles powered, for example, by gasoline generators. In addition, the vehicle can include a combination of an electric motor and a traditional internal combustion engine. In general, an electric vehicle battery EVB or traction battery is a battery for powering the propulsion of a battery electric vehicle BEV. Electric vehicle batteries are different from starting, lighting and ignition batteries because they are designed to give power for a sustained period of time. Rechargeable or secondary batteries are different from primary batteries in that they can be repeatedly charged and discharged, while the latter only provides irreversible conversion of chemical energy to electrical energy. Low-capacity rechargeable batteries are used as power sources for small electronic devices (such as cellular phones, notebook computers and video cameras), while high-capacity rechargeable batteries are used as power sources for hybrid vehicles, etc.

[0003] In general, a rechargeable battery includes an electrode assembly including a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode, a housing containing the electrode assembly, and electrode terminals electrically connected to the electrode assembly. An electrolyte solution is injected into the housing to enable charging and discharging of the battery via an electrochemical reaction of the positive electrode, the negative electrode, and the electrolyte solution. The shape of the housing, such as cylindrical or rectangular, depends on the intended use of the battery. Lithium-ion (and similar lithium polymer) batteries, which are widely known through their use in laptops and consumer electronic devices, dominate the development of recent electric vehicle groups.

[0004] The rechargeable battery can be used as a battery module formed by a plurality of unit battery cells coupled in series and / or in parallel, thereby providing high energy density in particular for the motor drive of a hybrid vehicle. That is, the rechargeable battery forms a battery module by interconnecting electrode terminals of a plurality of unit battery cells depending on the amount of power required and in order to achieve high power.

[0005] The battery module can be constructed in a block design or in a modular design. In the block design, each battery is coupled to a common current collector structure and a common battery management system, and its units are arranged in a housing. In a modular design, multiple battery cells are connected to form a submodule, and several submodules are connected to form a battery module. In automotive applications, the battery system is typically composed of multiple battery modules connected in series to provide the desired voltage. Among them, the battery module may include a submodule having a plurality of stacked battery cells, each stack including a plurality of parallel cells (XpYs) connected in series or a plurality of series cells (XsYp) connected in parallel.

[0006] A battery pack is a collection of any number of (preferably identical) battery modules. They can be configured in series, in parallel, or in a mix of both to deliver the desired voltage, capacity, or power density. The components of a battery pack include the individual battery modules and the interconnects that provide electrical conductivity between them.

[0007] To meet the dynamic power requirements of various electrical consumers connected to the battery system, static control of battery power output and charging is insufficient. Therefore, a stable exchange of information between the battery system and the controller of the electrical consumer is required. This information includes the actual charging state, SoC, potential electrical performance, charging capacity and internal resistance of the battery system, and the actual or predicted power demand or surplus of the consumer. Therefore, the battery system generally includes a battery system manager BSM, and further includes a plurality of battery module managers BMM, which are used to obtain and process such information at the system level. The BMM is part of the battery module of the system and obtains and processes relevant information at the system level. In particular, the BSM generally measures the system voltage, the system current, the local temperature at different locations inside the system housing, and the insulation resistance between the live components and the system housing. In addition, the BMM generally measures the voltage of each cell and the temperature of the battery module.

[0008] In the event of an abnormal operating state, the battery pack should generally be disconnected from the load connected to the terminals of the battery pack. Therefore, the battery system further includes a battery disconnect unit BDU electrically connected between the battery module and the battery system terminals. Therefore, the BDU is the main interface between the battery pack and the electrical system of the vehicle. The BDU includes an electromechanical switch that opens or closes the high current path between the battery pack and the electrical system. The BDU provides feedback, such as voltage and current measurements, to a battery control unit BCU accompanying the battery module. The BCU controls the switches in the BDU using a low current path based on the feedback received from the BDU. The main functions of the BDU may therefore include controlling the current flow and current sensing between the battery pack and the electrical system. The BDU may further manage additional functions like external charging and pre-charging.

[0009] Various control and communication processes regarding the BSM, its components or electrical consumers are time-dependent processes. Monitoring and controlling the charging of battery cells may require, for example, the determination of the rate of change of the charge state. In addition, during idle periods of the electrical consumers, i.e. periods of minimum load, various parameters, such as battery voltage and internal resistance, must be periodically controlled during wake-up periods to avoid system failures, e.g. due to thermal runaway or short circuits of individual cells. In order to provide, for example, a time scale for wake-up, the electronic control device of the battery system, i.e. the BSM, includes a real-time clock RTC.

[0010] The RTC is usually provided as an integrated circuit IC and may include a crystal oscillator or may use the power line frequency for deriving the time stamp. The RTC must be continuously energized to keep track of the running time, and the RTC may further include volatile or non-volatile memory to save information about the time such as the calendar date. For safety reasons, an alternative power source may be provided in addition to the main power supply, such as a lithium button cell battery or a capacitor.

[0011] In the battery system of the BEV of the prior art, the 12V / 24V board net provides the RTC. However, if there is a loss in this domain, there is also a loss in time. In addition, low drop regulators LDO are frequently used to power the RTC, for example because the 12V domain has a very wide input range starting from low volts (about 3V) up to a load dump voltage of more than 30V. LDO is an active linear voltage regulator that dissipates power to regulate the output voltage. Therefore, the power consumption of LDO is very high. This is particularly disadvantageous with respect to the extended idle time of electric vehicles. In addition, the purchase cost of commercial LDO is very high.

[0012] Therefore, the object of the present invention is to provide an alternative power supply for an RTC of a battery system. Thus, the power supply should reduce the power consumption of the battery system, in particular during idle periods, while ensuring a safe power supply for the RTC during all operating states of the battery system and / or the RTC. In addition, the production costs of the battery system should be reduced. Summary of the invention

[0013] The present disclosure can avoid or at least reduce one or more disadvantages of the prior art. Specifically, the present disclosure relates to an electric vehicle battery system, including:

[0014] A high voltage system HV system having a plurality of connected rechargeable battery cells;

[0015] a low voltage system (LV system) having an operating voltage lower than that of the HV system, wherein the LV system supplies power to a battery system manager (BSM); and

[0016] Configure the real-time clock (RTC) used to provide system time to the BSM.

[0017] The RTC is located in the LV system and is at least temporarily powered by the HV system.

[0018] The electric vehicle battery system may further include a battery disconnect unit BDU including a BDU relay switchably opening or closing an HV line of the HV system and a BDU control unit adapted to control the BDU relay, wherein the BDU is adapted to exchange data with the BSM via the communication interface.

[0019] The RTC is integrated into the BDU.

[0020] The BDU may include a high voltage part HV part including a BDU relay and a low voltage part LV part including a BDU control unit; and the RTC may be arranged on the LV part of the BDU. The LV part and the HV part may be separated from each other by galvanic isolation.

[0021] The BDU may further include an RTC voltage supply unit configured to receive an input voltage from the HV system and provide a supply voltage at an output of the RTC voltage supply unit, wherein the RTC is electrically connected to and configured to draw power from the output of the RTC voltage supply unit.

[0022] The BDU control unit may be configured to operate the RTC voltage supply unit such that the RTC voltage supply unit is inactive in a first operating state of the battery system and is active in a second operating state of the battery system.

[0023] The RTC may be further configured to receive a supply voltage from the LV system or the RTC voltage supply unit, wherein the RTC is powered by the LV system in a first operating state of the battery system and is powered by the HV system in a second operating state of the battery system.

[0024] The RTC voltage supply unit may include a voltage divider configured to convert an input voltage from the HV system into a supply voltage.

[0025] According to another aspect of the present disclosure, an electric vehicle including the above-mentioned electric vehicle battery system is provided.

[0026] Further aspects of the invention are disclosed in the dependent claims or in the following description of the figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Features will become apparent to those skilled in the art by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

[0028] Figure 1 A battery system according to an embodiment of the present disclosure is schematically illustrated. DETAILED DESCRIPTION

[0029] Reference will now be made in detail to embodiments, examples of which are shown in the accompanying drawings. The effects and features of the exemplary embodiments and methods of implementing the same will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same originals, and redundant descriptions are omitted. However, the present invention may be embodied in a variety of different forms and should not be considered to be limited to the embodiments illustrated herein. Rather, these embodiments are provided as examples so that the present disclosure will be comprehensive and complete, and will fully convey the aspects and features of the present invention to those skilled in the art.

[0030] Therefore, processes, elements, and techniques that are not considered necessary for one of ordinary skill in the art to fully understand the aspects and features of the present invention may not be described.In the drawings, relative sizes of elements, layers, and regions may be exaggerated for clarity.

[0031] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, the use of "may" when describing embodiments of the present invention refers to "one or more embodiments of the present invention." In the following description of embodiments of the present invention, terms in the singular may include plural forms unless the context clearly indicates an exception.

[0032] It will be understood that although the terms "first" and "second" can be used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element without departing from the scope of the present invention. As used herein, the term "and / or" includes any and all combinations of one or more of the items listed in the association. For example, an expression of "at least one" when preceding a list of elements modifies the entire list of elements without modifying a single element of the list.

[0033] As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that one of ordinary skill in the art would recognize. Additionally, if the term "substantially" is used in combination with a feature that can be expressed using a numerical value, the term "substantially" means a range of + / - 5% of a value centered on that value.

[0034] Figure 1 1 is a top view illustrating an electric vehicle battery system 10 according to an embodiment, which is further referred to as a battery system 10 for readability. Note that Figure 1It is intended to provide a better understandability of the battery system 10 of the present disclosure, in particular a better understandability of the electrical connections between the battery modules 20, the battery disconnect unit BDU 50 and the battery system manager BSM 100 of the battery system 10. The battery system 10 is used in an electric vehicle.

[0035] The battery system 10 includes a battery pack 12 including a housing 14. The housing 14 can be assembled from several parts, such as a bottom plate including side walls and a top cover and an outer shell. The housing 14 is used to accommodate various components of the battery pack 12. These components may include parts of a cooling system, sensors for detecting the temperature and other operating conditions of the battery pack 12, at least one battery module 20, and a control unit for controlling the operating conditions of the battery pack 12. For the sake of simplicity, the following description is limited to those components of the battery pack 12 that are necessary for the present disclosure.

[0036] Basically, the battery system 10 includes a high voltage system HV system and a low voltage system LV system. In the HV system, there is a voltage higher than the voltage in the LV system. Specifically, the HV system includes a battery module 20 as a voltage source, and all conductive components of the battery pack 12 connected to the battery module 20 up to the positive and negative system terminals 16, 17. The electric motor for propulsion of the electric vehicle including the battery pack 12 will be connected to the system terminals 16, 17.

[0037] The HV system includes a battery module 20 as a high voltage source. Figure 1 As shown in the exemplary embodiment, the battery module 20 has ten aligned battery cells 22 stacked in a stacking direction with their wide side surfaces facing each other. The battery cells 22 of the battery module 20 are connected to each other via busbars 24 in a series configuration. Therefore, each busbar 24 connects one positive cell terminal 26 and one negative cell terminal 27 to each other. The plurality of battery cells 22 are interconnected by the respective busbars 24 between the positive and negative module terminals 30 and 31. Typically, the battery pack 12 for an electric vehicle includes a plurality of battery modules, but for illustrative purposes, the exemplary embodiment includes only one battery module 20.

[0038] The battery modules 20 are connected to the BDU 50 via high voltage lines 32, 33. Each battery module 20 may further include a battery module manager BMM 70 for obtaining and processing information such as cell voltage (voltage measurement device not shown) and cell temperature (e.g. measured via temperature sensor 72) of the battery cells 22. The BMM 70 may also allow balancing the charging of the individual battery cells 22 of the battery module 20.

[0039] In the event of an abnormal operating state, the battery pack 12 should generally be disconnected from the load connected to the system terminals 16, 17. Therefore, the battery system 10 further includes a battery disconnect unit BDU 50 electrically connected between the battery module 20 and the battery system terminals 16, 17. Therefore, the BDU 50 is the main interface between the battery pack and the electrical system of the vehicle. The BDU 50 includes BDU relays 52, 53, specifically an electromechanical switch that opens or closes the high current path between the battery pack 12 and the electrical system. Such an electromechanical switch may include a solid-state relay SSR. Therefore, the high voltage lines 32, 33 of the battery module 20 are switchably connected to the system terminals 16, 17 via the BDU relays 52, 53. The BDU 50 may further include safety circuits and electronic components similar to fuses. In the specific design of the BDU 50 and its components, those skilled in the art can adapt themselves to the prior art.

[0040] According to an exemplary embodiment, the BDU control unit 56 is connected to the BDU relays 52, 53 via a low current line to allow switching of the BDU relays 52, 53. The BDU control unit 56 is further connected to the BMM 70 via a low current line. In addition, the BDU 50 includes a communication interface 54 (e.g., a serial peripheral interface, SPI) for synchronous communication between the BDU control unit 56 and the BSM 100.

[0041] Here, the BDU 50 provides feedback, such as voltage and current measurements, to the BMM 70 that accompanies the battery module 20. The BMM 70 may control electromechanical switches in the BDU 50 via the BDU control unit 56. The primary functions of the BDU may thus include controlling current flow and current sensing between the battery pack 12 and the electrical system.

[0042] The BDU 50 may further manage additional functions such as external charging and pre-charging that may be initiated by the BSM 100. In particular, the BDU control unit 56 is configured to receive a signal indicating a fault in the battery system 10 and / or indicating a need to disconnect the battery module 20 from the load. In response to receiving such a signal, the BDU control unit 56 is further configured to control additional BDU relays 52, 53 to disconnect the battery module 20 from the corresponding system terminals 16, 17 (and thus from the downstream load). In other words, the BDU 50 is electrically connected to and selectively closes the electrical path between the module terminals 30, 31 and the battery system terminals 16, 17. Therefore, the BDU 50 may be adapted to exchange data with the BSM 100 via the communication interface 54. For example, in the event that the BSM 100 determines the presence of an abnormal condition in the battery system 10, the BSM 100 may execute or control the execution of at least one countermeasure associated with the determined abnormal condition, such as sending an alarm signal to the driver of the vehicle. In particular, the BSM 100 may send a disconnect signal to the BDU control unit 56 , which, in response to receiving the disconnect signal, controls the BDU relays 52 , 53 to disconnect the system terminals 16 , 17 from the module terminals 30 , 31 , respectively.

[0043] The LV system is used to supply power to connected low voltage consumer components, including the control unit of the electric vehicle, such as the BMS 100 and the BDU control unit 56. The LV system may further include signal lines or other low voltage wiring of the battery system 10. The LV system may include the low voltage battery 120 of the electric vehicle as a voltage source and may be part of the onboard power supply.

[0044] The BDU components of the HV system are provided in the HV portion 60 of the BDU 50, whereas the BDU components of the LV system are arranged in the LV portion 62. The HV portion 60 and the LV portion 62 are divided by galvanic isolation indicated by dashed line 64. The communication interface 54 and the BDU control unit 56 are part of the LV portion 62.

[0045] Various control and communication processes about the BSM 100, its components or electrical consumption devices are time-dependent processes. Monitoring and controlling the charging of the battery cells 22 may require, for example, determining the rate of change of the charge state. In addition, in the idle period of the electrical consumption device, that is, the period of minimum load, various parameters, such as battery voltage and internal resistance, must be periodically controlled during the wake-up period to avoid system failures, such as due to thermal runaway or short circuits of individual battery cells 22. In order to provide, for example, a time stamp for wake-up, the electronic control device of the battery system 10, that is, the BSM 100, includes a real-time clock RTC 80. Here, the RTC 80 is provided on the LV part 62 of the BDU 50, and a time signal can be sent to the BSM100 via the communication interface 54, that is, the RTC 80 provides the system time to the BSM 100. The RTC 80 can be an integrated circuit that provides the functionality of a general RTC. Therefore, the RTC 80 is integrated into the BDU 50, wherein the RTC 80 is arranged on the LV part 62 of the BDU 50. The RTC 80 can provide the system time to the BSM 100 via the communication interface 54 of the BDU 50 .

[0046] The BDU 50 is further adapted so that the RTC 80 is at least temporarily powered by the HV system. Therefore, the BDU 50 may include an RTC voltage supply unit 82 configured to receive an input voltage from the HV system and provide a supply voltage at the output of the RTC voltage supply unit 82. The RTC 80 is electrically connected to and configured to draw power from the output of the RTC voltage supply unit 82. Thus, a safe power supply of the RTC 80 is guaranteed during all operating states of the battery system 10.

[0047] Specifically, the BDU control unit 56 may be configured to operate the RTC voltage supply unit 82 so that the RTC voltage supply unit 82 is inactive in a first operating state of the battery system 10 and is active in a second operating state of the battery system 10. The RTC 80 may be further configured to receive a supply voltage from the LV system or the RTC voltage supply unit 82, wherein the RTC 80 is powered by the LV system in the first operating state of the battery system 10 and is powered by the HV system in the second operating state of the battery system 10. The RTC voltage supply unit 82 may include a voltage divider configured to convert an input voltage from the HV system into a supply voltage.

[0048] In other words, the RTC voltage supply unit 82 is configured to be inactive in a first operating state of the battery system 10 and active in a second operating state of the battery system 10. The second operating state of the battery system 10 is an idle or sleep mode of the battery system 10, whereas the first operating state is an active state of the battery system 10. The active state of the battery system 10 may occur during charging or when power is provided to a load. The active state is characterized in that the LV system provides a supply voltage to the RTC 80. Therefore, the RTC 80 is able to draw power, for example, via the BSM 100, in the first operating state.

[0049] In the second operating state, the RTC 80 can draw power from the HV system via the RTC voltage supply unit 82. Therefore, the power requirements of the RTC 80 can be met in both operating states even without active switching in the power circuit of the RTC 80. When the battery system 10 returns to the first operating state, the RTC 80 will be able to provide continuous system time to the BSM 100.

[0050] In order to adapt the input voltage of the HV system to a supply voltage that is a lower limit value according to the power demand of the RTC 80, the RTC voltage supply unit 82 may include a voltage divider (not shown in the figure). Such a voltage divider may be configured to convert the input voltage from the module terminals 30, 31 into a supply voltage for the RTC 80. For example, passive components may be used to adapt the output input voltage of the RTC voltage supply unit 82. Specifically, an ohmic resistor and / or a diode may be used to reduce the input voltage from the battery module 20. Due to the small current drawn by the RTC 80, the voltage drop on these passive components may be set to a minimum.

[0051] The RTC 80 draws power from the LV system of the battery system 10 in the first operating state, and draws power from the HV system via the RTC voltage supply unit 82 during the second operating state. Thus, the power requirements of the RTC 80 can be met in both operating states.

[0052] The electronic or electrical devices and / or any other related devices or components according to the embodiments of the present invention described herein can be implemented using any appropriate hardware, firmware (e.g., ASIC), software, or a combination of software, firmware, and hardware. In addition, the various components of these devices can be implemented on flexible printed circuit films, tape carrier packages (TCPs), printed circuit boards (PCBs), or formed on a substrate. The electrical connections or interconnections described herein can be implemented by wires or conductive elements on, for example, PCBs or another circuit carrier. The conductive elements can include metallization, such as surface metallization and / or pins, and / or can include conductive polymers or ceramics. In addition, electrical energy can be sent via wireless connections, such as using electromagnetic radiation and / or light.

[0053] In addition, the various components of these devices can be processes or threads running on one or more processors in one or more computing devices that execute computer program instructions and interact with other system components to perform the various functions described herein. Computer program instructions are stored in a memory implemented in a computing device that can use standard memory devices (e.g., random access memory (RAM)). Computer program instructions can also be stored in other non-transient computer readable media, such as CD-ROMs, flash drives, etc.

[0054] Furthermore, those skilled in the art will recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or that the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the scope of the exemplary embodiments of the present invention.

Claims

1. An electric vehicle battery system, comprising: A high voltage HV system having a plurality of connected rechargeable battery cells; a low voltage LV system having an operating voltage lower than that of the HV system, the LV system being powered by a low voltage power source separate from the rechargeable battery cells of the HV system, wherein the LV system supplies power to a battery system manager BSM; and A real-time clock RTC, configured to provide system time to the BSM; Wherein, the RTC is located in the LV system and is at least temporarily powered by the HV system.

2. The electric vehicle battery system of claim 1, further comprising: a battery disconnect unit BDU comprising a BDU relay switchably opening or closing an HV line of the HV system and a BDU control unit adapted to control the BDU relay, wherein the BDU is adapted to exchange data with the BSM via a communication interface, Wherein, the RTC is integrated into the BDU.

3. The electric vehicle battery system according to claim 2, wherein: The BDU comprises a high voltage HV part and a low voltage LV part, the HV part comprises the BDU relay, and the LV part comprises the BDU control unit; and Wherein, the RTC is arranged on the LV part of the BDU.

4. The electric vehicle battery system according to claim 3, wherein: The LV part and the HV part are separated from each other by galvanic isolation.

5. The electric vehicle battery system according to claim 2, wherein: The BDU comprises an RTC voltage supply unit configured to receive an input voltage from the HV system and to provide a supply voltage at an output of the RTC voltage supply unit, and wherein the RTC is electrically connected to and configured to draw power from the output of the RTC voltage supply unit.

6. The electric vehicle battery system according to claim 5, wherein: The BDU control unit is configured to operate the RTC voltage supply unit such that the RTC voltage supply unit is inactive in a first operating state of the battery system and is active in a second operating state of the battery system.

7. The electric vehicle battery system according to claim 6, wherein: The RTC is further configured to receive a supply voltage from the LV system or the RTC voltage supply unit, and The RTC is powered by the LV system in a first operating state of the battery system, and is powered by the HV system in a second operating state of the battery system.

8. The electric vehicle battery system according to claim 5, wherein: The RTC voltage supply unit includes a voltage divider configured to convert an input voltage from the HV system into the supply voltage.

9. An electric vehicle comprising the electric vehicle battery system of claim 1.

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