WO2023214870A1

WO2023214870A1 - An improved battery management system

Info

Publication number: WO2023214870A1
Application number: PCT/NL2023/050236
Authority: WO
Inventors: Ralf Arnoldus Antonius ADAMS; Hendricus Johannes Bernardus WIJNANS; Cornelis Gerardus Henricus Maria VAN DE WIEL; Eric Coenraad HUIJDING
Original assignee: Total Safety Solutions B.V.
Priority date: 2022-05-02
Filing date: 2023-05-02
Publication date: 2023-11-09
Also published as: NL2031755B1

Abstract

A battery management system for monitoring a rechargeable battery, comprising a controller for regulating charging of the rechargeable battery, at least one sensor communicatively connected to the controller for measuring current, voltage, temperature, pressure or leakage current, on the rechargeable battery, and wherein the system comprises a communication device for communicating externally about the measurement when the measurement of the at least one sensor is outside a predetermined operating range, characterized in that the system comprises an emergency electrical source independent of the rechargeable battery arranged to supply the controller with electrical energy, and wherein the controller is arranged to draw energy exclusively from the emergency source for external communication when the rechargeable battery moves outside the predetermined operating range.

Description

An improved battery management system

The present invention relates to battery management systems.

According to Barsukov, Yevgen; Qian, Jinrong (May 2013) , ISBN 9781608074914 A battery management system (BMS) is any electronic control device that monitors and regulates a rechargeable battery (cell or battery pack) in use. For example, a BMS is implemented to protect the battery from being used outside of a safe range of operations. To this end, the BMS may be configured to monitor battery status, calculate secondary data, and/or balance battery charging and discharging. The BMS is often equipped with sensors for measuring voltage, temperature and current. Voltage can be seen on the total voltage across the battery, that of individual cells or groups of cells. The BMS then allows the battery to operate only within a certain voltage range. Temperature can mean the temperature of the battery or specific individual cells. The BMS is then arranged to shut down the battery when the temperature exceeds a predetermined boundary value. Current can refer to the electric current being supplied to or taken from the battery. For example, the BMS limits the current input and output to prevent battery damage. Battery management systems are mainly used for batteries with a relatively high energy density, such as lithium-ion batteries .

The BMS can thus protect its battery by preventing it from operating outside its safe range of operations, such as:

- Overcurrent, it may differ in charging and discharging mode ;

- Overvoltage, such as during charging, especially important for lead-acid and Li-ion cells;

- Undervoltage, such as during discharge;

- Over-temperature

- Under-temperature

- Overpressure, for example with NiMH batteries;

- Earth leakage or leakage current detection, this allows the BMS to check if a high voltage battery is electrically disconnected from any conductive object touchable for use, such as the body of a vehicle. The BMS can prevent operation outside the safe working range of the battery by means of an internal switch, such as a relay, that opens if the battery is used outside the safe working range. This is a way to turn off the battery. In modern battery packs, the BMS can even communicate with attached devices, telling them to, for example, reduce or even terminate battery usage. This is also known from the electric vehicle industry. In some cases, the BMS has even been designed to actively manage the battery environment by controlling heating, fans, air conditioning or liquid cooling.

BMS topologies fall into three categories:

- Centralized: a single controller is connected to the battery cells of a rechargeable battery through a plurality of electrical wires or cables;

- Distributed: each cell is equipped with a locally installed controller, with only a single communicative link between the battery and an end controller for the local controllers; and

- Modular: a plurality of controllers, each controlling a certain number of cells, with mutual communication between the controllers.

The controller of a BMS communicates internally with its cell-level hardware, or externally with high-level hardware such as laptops or an HMI .

A problem with Lithium-ion (Li-ion) batteries in particular is that damaged batteries pose a risk of ignition, even when such a battery is switched off by a BMS connected to it. In the event of a leak or damage, an unwanted electrochemical (side) reaction can cause the temperature of the battery to rise, a so- called 'thermal runaway' . The BMS no longer has any significant control over the battery during the occurrence of such a thermal runaway. An unfavorable side effect is that the BMS will put a strain on the already damaged battery for external communication .

In the case of critical damage, such a load on the battery is either not possible or otherwise highly undesirable. In practice, this means that the BMS will turn itself off or fail due to an inadequate electrical supply. It is then not under all possible circumstances to send an external signal about a risk situation, such as thermal runaway.

The present invention seeks to provide a solution in the aforementioned situation and to provide a battery management system that is able to continue to communicate externally in the event of critical damage to the battery without burdening the damaged battery through active communication, and to support it communicatively where otherwise the BMS would no longer be active .

External communication can occur via serial communication; CAN bus communication, widely used in automotive environments; and wireless communication. The system according to the invention is particularly effective for external wireless communication, since such communication is energy intensive.

According to a first aspect of the invention, a battery management system for monitoring a rechargeable battery, such as a battery pack of an electric vehicle, is provided. The system comprises a controller for regulating charging of the rechargeable battery, and at least one sensor communicatively connected to the controller for measuring current, voltage, temperature, pressure or leakage current at the rechargeable battery. The controller comprises a communication device for communicating externally about the measurement when the measurement of the at least one sensor is outside a predetermined operating range. The system is characterized by an electrical emergency source arranged independently from the rechargeable battery for supplying electrical energy to the controller, and the controller being arranged to, for external communication, draw electrical energy exclusively from the emergency source when the rechargeable battery moves out of the predetermined operating range. The system can herein, also apart from this example, be designed to switch from the rechargeable battery to the emergency source when the rechargeable battery moves outside the predetermined operating range. The emergency source may be designed to provide direct current with a voltage of 3-20 V, preferably 12 V. In an example, this system is connected to at least one rechargeable battery, said at least one rechargeable battery forming part of a high-voltage battery bank in an electric vehicle. In such an example, the back-up source is configured not to serve as an auxiliary battery for auxiliary systems on board the vehicle. An auxiliary battery is usually a 12 V battery for auxiliary systems on board a vehicle, such as central locking, lighting and the infotainment system.

When the rechargeable battery, often a high voltage series of smaller batteries, is switched off, only a limited amount of electrical power is available to allow the system to measure and communicate. To extend the duration of the system's operation, the system is optionally configured, such as pre-programmed, to perform periodic repeat measurements on the rechargeable battery and to communicate these measurements externally. Such measurements are then carried out, for example, only when the controller is exclusively dependent on the electrical energy of the emergency source. This solution is particularly useful in situations where battery damages have latent consequences. Because of this the BMS will also still be active when latent effects occur, and may timely warn of thermal runaway.

In a more advantageous embodiment, the periodic repeat measurements are divided between a first period and a second period following the first period, and wherein the frequency of repeat measurement and/or communication of repeat measurements is lower over the second period than over the first period. Optionally, the first period can then be 1-48 hours, and the second period 1-21 days. The frequency of the first period can vary between 1 millisecond - 15 minutes and between 1 second - 1 hour. As a result, shortly after a so-called 'shut down event' of a rechargeable battery the battery is closely monitored. If there is no catastrophic failure of the battery within the first period, then the rest of the available electrical energy is rationed over a longer period to still be able to detect latent problems. A shut down event is moreover a situation in which the controller prevents the rechargeable battery from being used for charging or discharging electrical energy. A system's controller may be configured to disconnect the battery when the battery moves outside the safe operating range. Optionally, the at least one sensor comprises a temperature sensor for measuring temperature at the rechargeable battery. The controller is arranged to extract electrical energy exclusively from the emergency source for external communication when the measured temperature is outside a predetermined operating range, in particular above a predetermined limit temperature.

This limit temperature is, for example, an upper limit temperature between 50-90 degrees Celsius and/or a lower limit temperature between 5 and -30 degrees Celsius. The BMS normally draws energy from the rechargeable battery for its own functioning in such situations. The system according to the invention prevents this unnecessary load and can for instance be designed to extract energy from the rechargeable battery again when the at least one sensor indicates that the battery has again moved to within the boundary values. In addition, the system can be arranged to also prevent this return to the drawing of energy from the rechargeable battery if the boundary value has been exceeded by more than a predetermined amount or percentage. For example, the rechargeable battery may be irreparably damaged above or below certain temperatures. A return to a relatively normal temperature can then be an unreliable indication that the battery could again be reliably burdened .

Optionally, the external communication device is a wireless communication device, such as telephone 2G, 3G, 4G, 5G, Wifi, Bluetooth, etc. , in which emergency source is designed as a battery and is connected to incoming electrical communication lines and/or pilot lines, such as a proximity pilot or control pilot line. Alternatively, the emergency source can be designed as a capacitor. The wireless communication device is preferably adapted in terms of electrical consumption in terms of capacity to the emergency source in such a way that the system can send real-time information about the measurements for at least 24 hours. Real time refers to sending measurements with a frequency no lower than 10s. This functional ratio prevents the system from becoming unnecessarily heavy. The emergency source may be designed as part of a block or regulator communicatively connected to the controller, wherein the corresponding communicative connection between block and controller being separate from the electrical communication lines. The charging lines can also serve as so-called mail supply, these are lines over which the controller can both receive electrical energy from a source other than the rechargeable battery and

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6 communicate electrically. The block includes the communication device. Block here is a term for building block, and simply refers to a printed circuit board.

In one example, the emergency source is a non-rechargeable battery, which may be of a replaceably arranged, with a passive lifespan of at least 10 years. This means that the capacity, also called energy content, of the non-rechargeable battery has been chosen in such a way that the battery is able to function for at least a period of two weeks, whereby the period can be divided into a first and a second period, with mutually different frequencies of communication and/or measurement.

In situations where a battery threatens to undergo a critical failure, it is of great importance that the battery is identified as quickly as possible. A battery that is part of an e-bike is hard to find when the bike is parked in a crowded storage. The same applies to a vehicle when it is parked between other electric vehicles, especially when they are of the same type. When several electric vehicles or battery carriers are near each other, a so-called domino effect can occur in the event of a critical failure. In an example from 2021, the fire of an electric vehicle resulted in the fire of a vehicle parked next to it .

The Washington Post published the following article about this : Because the percentage of electric vehicles and therefore high- voltage and high-capacity battery carriers is increasing, the number of incidents is increasing. A single thermal runaway can therefore have major consequences. Especially in parking lots, the damage is often incalculable. For this purpose, the system may be equipped with a GPS. The system is further designed to provide external communication about the measurements with information about the location of the system. This allows a user of, for example, an external device such as a telephone, tablet, laptop, or plug to identify the failing battery more quickly in a busy parking lot based on the external communication.

In garages, which often consist of several floors, it can also be difficult to find the vehicle immediately based on a GPS location. The system can therefore be designed, read preprogrammed, to form a communicative network with other systems. That is to say that the system is arranged, for instance by means of the communication device, to generate a wireless warning signal in the event of or preventively of thermal runaway. The system is then also designed to receive and pass on warning signals from other systems within a predetermined distance, for example to a central server or to an external device, such as a telephone, tablet or laptop.

This allows owners of neighboring vehicles to move their vehicle in a timely manner in response to the transmitted signal. Alternatively, the system is arranged to communicate with the autopilot of the vehicle to automatically move the vehicle to a safe distance in response to the received signal. To this end, the controller be configured to communicate with the vehicle's CPU via the CAN bus where the CPU, in response to a command from the system, invokes the vehicle's autopilot to increase the distance between the vehicle and the source of the signal. To this end, the system may be configured to communicate the change in relative signal strength to the vehicle's CPU, with the autopilot configured to control the vehicle so that the relative signal strength is reduced below a predetermined value, whereupon the pilot activates parking mode and automatically parks at the new location.

According to a further embodiment, the system may be configured to be communicatively connected to a pilot line, such as a proximity pilot line or control pilot line, and a CAN bus, the system being configured to respond to a first command signal over the pilot line to send a second command signal over the CAN bus. This adaptation allows emergency services to feed instruction signals to deeper systems in the vehicle that would otherwise be inaccessible or difficult to access through the charging port. The pilot line terminates at the charging port. Optionally, a charging port, or an OBD port elsewhere external to the vehicle can be provided. It is common for the OBD port in vehicles to be connected to the vehicle's CPU, or at least already provides direct access to the CAN bus itself.

Currently, however, OBD ports are difficult to access in the event of an accident, such as within the cabin. The first and second instruction signal may be the same signal in terms of information content. Optionally, the communication device may be arranged to detect the instruction signal, such as the first or second signal if they are not the same, as a superimposed signal on a pilot signal.

According to a second aspect of the invention, a method is provided, comprising the steps: i) providing a system according to the first aspect of the invention; ii) making a measurement of at least one of a current, voltage, temperature, pressure or leakage current at the rechargeable battery; iii) determining whether the measurement is outside a corresponding operating range; iv) switching to exclusive use of the emergency electrical source for external communications; v) performing repeat measurements on the rechargeable battery for externally communicating information about the repeat measurements and/or communicating a warning signal.

Optionally, the system comprises the use of a central server, the external communication being wireless with this central server, and the method comprising the step of: vi) communicating a warning signal to a portable telecommunication device over a mobile network based on measurements outside the operating range.

It is also possible for the step of contacting emergency services to provide a warning about thermal runaway and the location of the system.

Possibly, contacting takes place by telephone via the server by means of a robot voice, and the server being configured to automatically navigate a selection menu of an emergency services, such as 112. This is just a notable example. Alternative contact steps are also possible. This is merely a single example.

The invention is further discussed in reference to the following figures:

- Fig. 1 schematically shows a system according to the invention; - Fig. 2 schematically shows a network of systems according to the invention; and

- Fig. 3 schematically shows an alternative network of systems according to the invention.

Figure 1 shows a battery management system 1, also called BMS, for monitoring a rechargeable battery 2, comprising a controller 3 for regulating the charging of the rechargeable battery. The battery in this example can be a high-voltage battery pack, such as that of an electric vehicle. In this example, the controller 3 is already designed as a conventional BMS and is communicatively connected to at least one sensor 4. In this example, this sensor is a temperature sensor for measuring temperature on the rechargeable battery. The controller 3 has a communication device 5 for communicating externally about the measurement when the measurement of the at least one sensor 4 lies outside a predetermined operating range. The communication device is communicatively connected to the controller and in this example implemented on a separate building block B.B. , such as a separate printed circuit board. However, this is not necessary. The communication device can also be integrated with the controller. The system 1 is further provided with an electrical emergency source 6 independent from the rechargeable battery. Independent here refers to the fact that the emergency source can be used separately from the rechargeable battery by the system for supplying electrical energy to its components. The emergency source in this example is a non-rechargeable battery. The controller 3 is also arranged to extract electrical energy exclusively from the emergency source for external communication when the rechargeable battery goes outside the predetermined operating range. In this example, the communication device 5 is a transponder for wireless communication over a mobile network 1, such as a telephone network. The emergency source 6 is connected to incoming and outgoing electrical communication lines 7. The corresponding communicative link 8 between block B.B. and the controller is further designed separately from the electrical communication lines 7 which are addressed by the emergency source in order to supply the controller 3 communication device 5 with electrical energy. The block may further be provided with a GPS (not shown, but customary) .

In the system according to the example of Figure 1, the controller 3 itself is implemented as a battery management system with a centralized topology for a high-voltage rechargeable battery, as according to https : / / web . archive . org/ web/ 20220502094621 /https : / / www . ionener gy .co/ resources /blogs /hv-batt ery-management- systems / .

High-voltage being 400 V and above. Alternatively, the controller is implemented as a battery management system terminal controller, also called Master BMS, communicatively connected to a plurality of local controllers, also called Slave BMS, in a distributed battery management system. The system according to the invention can therefore serve as a central emergency facility for a decentralized control system.

Figure 2 shows the systems 1 of three different vehicles or devices in a communicative network 100, where the systems communicate with each other via the wireless network to send out a warning signal ! . This is especially useful in car parks where certain vehicles are parked in such a way that mobile communication is not possible. In this example, the outgoing signal i with warning is received by an external device EA with a human interface, such as a telephone, tablet, laptop.

Figure 3 shows a network of systems according to Figure 1, in which communication takes place via a distant central server

Claims

1. A battery management system (1) for the protection of a rechargeable battery (2) , comprising a controller (3) for the regulating the charging of the rechargeable battery, at least one sensor (4) communicatively connected to the controller for measuring of current, voltage, temperature, pressure or leakage current, at the rechargeable battery, and wherein the system comprises a communication device (5) for communicating externally about the measurement when the measurement of the at least one sensor is outside a predetermined operating range, characterized in that the system comprises an emergency electrical source (6) which is arranged independent of the rechargeable battery to supply the controller with electrical energy, and wherein the controller (3) is adapted to extract electrical energy for external communication exclusively from the emergency source when the rechargeable battery moves outside the predetermined operating range.

2. The system according to claim 1, characterized in that the controller (3) is pre-programmed to detect, preferably pre-emptively detect, thermal runaway on the basis of the measurements of the at least one sensor (4) , and wherein the communication device (5) is configured to send a warning signal in response to such detection.

3. The system according to claim 1 or 2, characterized in that the system is arranged to perform periodic repeat measurements on the rechargeable battery for external communication when the controller is exclusively dependent on the electrical energy of the emergency source.

4. The system according to claim 1, 2 or 3, characterized in that the at least one sensor comprises a temperature sensor for measuring temperature at the rechargeable battery, and wherein the controller is adapted to extract electrical energy exclusively from the emergency source for external communication when the measured temperature is outside a predetermined operating range, in particular above a predetermined limit temperature.

5. The system according to any one of claims 1-4, comprising the characterized in that the external communication device (5) is a wireless communication device, and in which the emergency source is a battery and is connected to incoming electrical communication lines (7) .

6. The system according to claim 5, characterized in that the wireless communication device, in terms of electrical consumption and emergency source in terms of capacity, are matched in such that the system is able send real-time information about the measurements for at least 24 hours.

7. The system according to claim 5 or 6, characterized in that the emergency source is designed as part of a block (B.B) or regulator connected communicatively to the controller, and wherein the corresponding communicative connection (8) is formed separately from the electrical communication lines (7) which are addressed by the emergency source to supply the controller (3) communication device (5) with electrical energy.

8. The system according to any of claims 1-7, characterized in that the emergency source comprises a non- rechargeable battery, optionally replaceable arranged, with a passive lifespan of at least 10 years.

9. The system of any one of claims 1-8, comprising a GPS, wherein the system is configured to provide external communication about the measurements with information about the location of the system.

10. The system of any one of claims 1-9, configured to be communicatively connected to a) a pilot line, such as a proximity pilot line or control pilot line, and a CAN bus, where the system is configured to transfer an instruction signal over the pilot line to the CAN bus ; or b) an OBD port accessible externally to a vehicle, where the system is arranged to propagate an instruction signal on the OBD port over a CAN bus .

11. The system according to claim 10, wherein the controller (3) or the communication device (5) is configured to detect the instruction signal as a superimposed signal on a pilot signal .

12. The system according to any of claims 1-11, wherein a) the controller (3) itself is designed as a battery management system with a centralized topology or b) the controller (3) itself is desgined as a battery management system terminal controller communicatively connected to a plurality of local controllers in a distributed battery management system.

13. A computer-implemented method comprising the steps : i) providing a system according to any of claims 1- 12; ii) making a measurement of at least one of a current, voltage, temperature, pressure or leakage current on the rechargeable battery; iii) determining whether the measurement is outside a corresponding operating range; iv) switching to exclusive use of the emergency electrical source for external communications; v) performing repeat measurements on the rechargeable battery for externally communicating information about the repeat measurements and/or communicating a warning signal.

14. The method according to claim 13, characterized in that the system according to at least claim 4 or 5 is provided, and a central server (10) , the external communication with a central server being wireless, and wherein the method comprises the step of: vi) communicating a warning signal to a portable telecommunication device over a mobile network based on measurements outside the operating range.

15. The method of claim 14, comprising the step of contacting emergency services to provide a warning about thermal runaway and the location of the system.

16. The method of claim 15, wherein said contacting occurs by telephone through the server by robotic voice, and wherein the server is configured to automatically navigate an emergency services selection menu, such as 112.