Description of Invention

Embodiments of the present invention relate to battery controller communication systems, a battery system, and a vehicle.

Microcontrollers may be provided in relation to batteries and battery arrays. These microcontrollers may perform a number of different tasks including monitoring battery voltage and/or providing battery balancing in an array of batteries.

There is a desire to reduce the component cost of implementing microcontroller monitoring and/or control, improve reliability, reduce the electrical power drain through the use of such microcontrollers, and/or to improve communication speed in relation to these microcontrollers.

Accordingly, embodiments seek to alleviate one or more problems associated with the prior art.

An aspect of the present invention provides a battery controller communication system for providing communication between a parent and a child controller of a battery system including at least one battery, the battery controller communication system including: an input configured to receive information from the parent controller as an input signal; an output configured to provide the information to the child controller as an output signal; and a switch circuit configured to detect the input signal, to turn on electrical power to the child controller on detection of the input signal, and turn off electrical power to the child controller after the input signal ceases. The switch circuit may be further configured to turn off electrical power to the child controller a predetermined period after the input signal ceases.

The switch circuit may include a timer circuit which is configured to control the provision electrical power to the child controller after the input signal ceases.

The timer circuit may include a charge storage device which is charged by the input signal and the discharge of which controls when electrical power to the child controller is turned off.

The communication system may further include one or more switch devices coupled to the timer circuit and which are configured to actuated by the timer circuit to control the provision of electrical power to the child controller. The switch circuit may be further configured to control the provision of the input signal to the output.

The communication system may further include an optocoupler in a communication pathway between the input and the output.

The communication system may further include an optocoupler driver circuit configured to drive operation of the optocoupler; and an input voltage filter coupled to an output of the optocoupler and an input of the switch circuit, wherein the input voltage filter and optocoupler driver circuit are configured to limit a voltage range of the output from the optocoupler.

The input voltage filter may include a comparator which is configured to compare the output of the optocoupler with a voltage which is dependent on and less than a voltage of the battery. The optocoupler driver circuit may be configured to drive a light emitter of the optocoupler based on the input signal and a reference voltage to compensate for voltage variations from the battery. An aspect provides a battery controller communication system for providing communication between a parent and a child controller of a battery system including at least one battery, the battery controller communication system including: an input configured to receive information from the parent controller as an input signal; an output configured to provide the information to the child controller as an output signal; an optocoupler in a communication pathway between the input and the output; an optocoupler driver circuit configured to drive operation of the optocoupler; and an input voltage filter coupled to an output of the optocoupler and an input of the switch circuit, wherein the input voltage filter and the optocoupler driver circuit are configured to limit a voltage range of the output from the optocoupler.

The input voltage filter may include a comparator which is configured to compare the output of the optocoupler with a voltage which is dependent on and less than a voltage of the battery.

The optocoupler driver circuit may be configured to drive a light emitter of the optocoupler based on the input signal and a reference voltage to compensate for voltage variations from the battery. Another aspect provides a battery system including the communication system as above and the at least one battery, wherein the child controller is configured to be powered by the at least one battery.

Another aspect provides a vehicle including a communication system as above or a battery system as above. Embodiments are described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a battery system according to some embodiments;

Figure 2 shows a communication system of some embodiments;

Figure 3 shows an optocoupler of some embodiments; Figure 4 shows an optocoupler driver circuit of some embodiments;

Figure 5 shows a switch circuit of some embodiments; and

Figure 6 shows a return communication circuit of some embodiments.

With reference to figure 1 , there may be provided a battery system 1. The battery system 1 may include one or more batteries 11 which each may comprise one or more cells. As such, the term“battery” as used herein may be a reference to a single battery cell or to an array of battery cells. If a plurality of batteries 11 is provided as part of the battery system 1 , then the plurality of batteries 11 may form an array of batteries (which may, therefore, be an array of battery cells).

The battery system 1 may include one or more controllers 12 which will herein be referred to as one or more child controllers 12. The or each controller 12 may be a respective microcontroller 12 (i.e. a respective child microcontroller 12).

The battery system 1 may include one or more further controllers 13 which will herein be referred to as one or more parent controllers 13. The or each further controller 13 may be a respective microcontroller 13 (i.e. a respective parent microcontroller 13).

The or each child controller 12 may be associated with a respective battery 11 of the one or more batteries 11. In some embodiments, the or each child controller 12 is associated with a plurality of batteries 11 of the one or more batteries 11 (which, therefore, comprise a plurality of batteries 11 ). The or each child controller 12 may be configured to collect information regarding the operation of the or each associated battery 1 1. The or each child controller 12 may be configured to communicate collected information about the operation of the or each associated battery 11 to an associated parent controller 13 of the one or more parent controllers 13.

The or each child controller 12 may be configured to control one or more aspects of the operation of the associated battery 11 or batteries 11. This may include, for example, controlling the power delivered by the or each associated battery 11 to equipment to be powered by the battery system 1 and/or controlling the power delivered to the or each associated battery 11 from a charging system for the battery system 1.

The or each parent controller 13 may be configured to collect information provided by the or each associated child controller 12. The or each parent controller 13 may be configured, for example, to use the collected information to control one or more aspects of the operation of the or each associated child controller 12 - e.g. controlling how the or each associated child controller 12 controls one or more aspects of the operation of the associated battery 11 or batteries 11.

The or each child controller 12 may, therefore, be configured to receive one or more control instructions from the or each parent controller 13. In other words, the or each child and parent controllers 12,13 may provide a control and monitoring hierarchy for the or each battery 11 of the battery system 1. The or each child controller 12 may be configured to receive electrical power for its operation from the or each associated battery 11. In this respect, the or each child controller 12 may be substantially permanently connected to terminals of the associated battery 11 or batteries 11 (e.g. via one or more part of embodiments described herein). This may be referred to, for example, as the child controller 12 being hardwired to the or each associated battery 11.

In a conventional battery system, such an arrangement may cause problems as controllers, such as the child controller(s) 12, may fail - e.g. by crashing. This may then require the controller 12 to be reset or otherwise disconnected from the power source (e.g. the associated battery 11 or batteries 11 ). This, in turn, requires the ability to be able to identify such failures - such as watchdog circuits. In addition, reset mechanisms must also be provided for automated or manual actuation in the event of a failure. Therefore, a conventional battery system attempting to implement such a design may require, for example, additional sequential logic and/or other hardware components. Furthermore, failure of a controller can cause a significant risk of damage to the battery 11 or batteries 11 and/or equipment powered by the battery 11 or batteries and/or other property. The or each child controller 12 of some embodiments may need to be galvanically isolated from at least one other of the child controllers 12 and/or may have a different ground thereto. The or each child controller 12 may be galvanically isolated, and/or have a different ground, from the or each parent controller 13. With reference to figure 2, in some embodiments, there may be provided a communication system 2 for use in a battery system 1 such as the system 1 described herein. The communication system 22 may be part of the battery system 1. The communication system 22 may be configured to provide a communicative coupling between at least one of the or each child controllers 12 and at least one of the or each parent controllers 13. The description will refer to the coupling of one child controller 12 to one parent controller 13 for the sake of simplicity but is to be understood to encompass, in some embodiments, other arrangements. Likewise embodiments may be used to connect, communicatively, another form of source and destination device.

In figure 2, the parent controller 13 is also referenced as“BA” or the source of information to be communicated. The child controller 12 is also referenced as “AD” or the destination for the information to be communicated (e.g. from the parent controller 13). Embodiments may be applied in different situations and so, in some embodiments, the source of information may not be a controller or even the parent controller 13. Likewise, the destination of the information may not be a controller or even the child controller 12. Likewise, bi-directional communication may be provided in some embodiments - which may be initiated by the source (e.g. the parent controller 13).

The communication system 2 may include one or more components forming a communication channel or pathway between the destination controller 13 and the child controller 12 (or other source and destination).

The communication channel may be a wired communication channel and the communication protocol could take a number of different forms. In some embodiments, the communication channel is a serial communication channel configured for asynchronous communication. In some embodiments, the communication channel may be a UART channel. The one or more components of the communication system 2 may include an optocoupler 22 (also referenced as“AB”). The optocoupler 22 may, therefore, provide galvanic isolation between the child controller 12 and the parent controller 13.

An example optocoupler 22 is shown in figure 3. The optocoupler 22 may include a light emitting element (such as a light emitting diode) located relative to a light receiving element (such as a phototransistor), for example. The optocoupler 22 may be configured to receive an electrical signal (e.g. at N3), to convert the electrical signal into a light signal and then back into an electrical signal which is then output (e.g. at N4).

The one or more components of the communication system 2 may include an optocoupler driver circuit 23 (also referenced as “BB”). An example optocoupler driver circuit 23 is shown in figure 4. The optocoupler driver circuit 23 may be configured to receive a digital signal input (e.g. at N1 ) representing the information to be communicated over the optocoupler 22 (i.e. an input signal). An analog signal (the optocoupler driver signal) is then generated and output by the optocoupler driver circuit 23 to drive operation of the optocoupler 22 (and, in particular, the light emitting element thereof). The output by the optocoupler driver circuit 23 may be output on N3, for example.

The optocoupler driver circuit 23 is configured to generate the optocoupler drive signal based at least in part on a reference voltage. In particular, an electrical current of the optocoupler drive signal may be based at least in part on the reference voltage and at least in part on the digital input signal (e.g. as provided at N1 ). The reference voltage may be provided to compensate for variations in the voltage of the or each battery 11 with which the child controller 12 is associated. The reference voltage (e.g. at N2) may be provided by the source (e.g. the parent controller 13). The reference voltage may vary during communication between the source and destination. The reference voltage may be set according to a plurality of different modes of reference voltage selection. In a first mode, a plurality of different predetermined reference voltages may be used sequentially. Between each of the plurality of reference voltages, the source (e.g. the parent controller 13) or another circuit may determine whether or not there is a response from the destination (e.g. the child controller 12). If a response is received, then the last predetermined reference voltage may be set as an initial reference voltage and the sequential application of different reference voltages may be discontinued. The application of the sequence of reference voltages may be a discovery mode. The application of the initial reference voltage may be an initial mode. The discovery mode and the initial mode may be followed by a feedback mode. In the feedback mode, the reference voltage may be determined based on information received from the destination (e.g. the child controller 12). This information may include, for example, a voltage of the or each associated battery 11. This information be provided by a digital to analog converter provided in the source (e.g. the parent controller 13). During the feedback mode, the reference voltage may track the voltage of the or each associated battery 11.

These one or more components may include a switch circuit 21 (also referenced as “AC”). The switch circuit 21 may be configured to control electrical power selectively to the destination for the information, which may be the child controller 12. This selective control may enable the turning on and off of the destination for the information (e.g. the child controller 12). The switch circuit 21 may also or alternatively open or close the communication pathway between the source and destination (e.g. between the parent and child controllers 12,13). The electrical power which is selectively controlled may include the electrical power which is used by the child controller 12 to perform its operations. The electrical power which is selectively switched may, however, be provided by the one or more batteries 11 with which the child controller 12 (or other destination) is associated.

In some embodiments, the switch circuit 21 may be a timed switch circuit 21. The timed switch circuit 21 may be configured to provide electrical power to the child controller 12 (or other destination), e.g. from the or each associated battery 11 , during communication from the source of the information (e.g. the parent controller 13) and for a predetermined period after communication from the source of the information (e.g. the parent controller 13) has ended. The timed switch circuit 21 may be configured to discontinue or otherwise stop the provision of electrical power to the child controller 12 (or other destination), e.g. from the or each associated battery 11 , after the predetermined period.

The switch circuit 21 could take a number of different forms and an example is shown in figure 5. The switch circuit 21 includes an input voltage filter 211. The input voltage filter 211 may be configured to filter the output from the optocoupler 22 and to reduce noise on that output, to generate a filtered signal (the voltage range of which is determined by the voltage of the electrical power supply to the input voltage filter 211 which may be provided by the or each associated battery 11 ). The input voltage filter 211 may form part of a input voltage range limiter which is configured to reduce the voltage range over which the optocoupler 22 is permitted to operate. This, in turn, operates to negate the effects of slew rates on communication speed and allows for faster communication of the information over (i.e. through) the optocoupler 22. The optocoupler driver circuit 23 may also form part of the input voltage range limiter. In particular, the use of the reference voltage by that optocoupler driver circuit 23 (e.g. at N2) (and the switch Q8) may form a function of the input voltage range limiter and may be a part thereof.

The input voltage filter 211 is configured to receive the output (e.g. from N4) of the optocoupler 22 and a reference voltage (e.g. at N5). The reference voltage is based at least in part on the voltage of the one or more batteries 11 with which the destination (e.g. the child controller 12) is associated. The input voltage filter 211 may be configured to output the filtered signal which is based on the output from the optocoupler 22 and the reference voltage. This filtered signal may be within a range determined by the voltage of the or each battery 11 (at P1 ). The input voltage filter 211 may include, therefore, a comparator with the reference voltage as an input to an inverting input and the output from the optocoupler 22 as an input to an inverting input, with the comparator powered by the or each associated battery 11. The reference voltage may be generated using a potential divider coupled to the or each associated battery 11.

The switch circuit 21 may include a timer circuit 212. The timer circuit 212 may be configured to turn on the electrical power to the destination (e.g. the child controller 12) - that power being provided by the or each associated battery 11 - on receipt of a signal from the source (e.g. the parent controller 12) and, in particular, on receipt of a signal from the optocoupler 22 indicating such communication is occurring (which may come using the input voltage range limiter (i.e. as the filtered signal) or not). When the signal from the optocoupler 22 (however received) ceases, then the timer circuit 212 may be configured keep electrical power to the destination (e.g. the child controller 12) turned on for a predetermined period before causing that electrical power to be turned off. The signal from the source (e.g. the parent controller 13) may be the signal conveying the information to be communicated to the destination (e.g. to the child controller 12). The timer circuit 212 may include a capacitor (C1 ) or other charge storage circuit 213 which is configured to be charged when the signal from the source (e.g. the parent controller 12) is received, to remain charged whilst that signal is being received, and to discharge once the signal ceases. The charge storage circuit 213 may be coupled to a switch sub-circuit of the switch circuit 21 to cause the switching of the delivery of electrical power to the destination (e.g. the child controller 12). The speed of discharge of the charge storage circuit may, therefore, provide the predetermined period before the electrical power is turned off. The timer circuit 212 may include one or more resistors and/or other components (such as Q1 and Q2) which are configured to provide the required charge and discharge characteristics for the charge storage circuit 213. The may include the resistors depicted as R1 and R2. In some embodiments, R2 has a higher resistance than R1. In some embodiments, R2 has a resistance of around 1000 times that of R1. This may allow the relatively fast charging of the charge storage circuit 213 compared to its discharge - discharge being through R2 for example.

The switch sub-circuit may include one or more switch elements which may include one or more transistors which may be MOSFETs, for example. The switch elements of the switch circuit may include Q3, Q4, Q5, and Q6.

In particular, the charge state of the charge storage circuit 213 may control the operation of a first switch device (Q3), which may cause the turning on of electrical power to the destination (e.g. the child controller 12) and may cause the signal from the optocoupler 22 (using the input voltage range limiter or otherwise) to be provided to the destination (e.g. the child controller 12). The first switch device (Q3) may cause this operation using one or more further switch devices (Q4, Q5, and Q6). In particular, the state of a second switch device (Q3) may control the state of a third switch device (Q4) which may turn on (or off) the electrical power to the destination (e.g. the child controller 12) - i.e. using P2 for the delivery of power to the destination (e.g. the child controller 12). This may, in turn, control the state of a fourth switch device (Q5) and of a fifth switch device (Q6) which determine whether the output from the optocoupler 22 (using the input voltage range limiter or otherwise) is communicated to the output of the switch circuit 21 which is the input to the destination (e.g. the child controller 12) - e.g. as an output signal from the communication system 2.

Therefore, in other words, the switch circuit 21 may include a timer circuit 212 which is configured to receive the output from the optocoupler 22 (directly or using the input voltage range limiter). The timer circuit 212 (e.g. using the charge storage circuit 213) is configured to control one or more switch devices (such as Q3 and Q4) which cause the turning on or off of the electrical power to the destination (e.g. the child controller 12) (e.g. at P2). This includes the turning on when a signal is received and the turning off a predetermined period after the signal ceases, as described herein. One or more other switch devices (such as Q5 and Q6) control the provision of the signal also to the destination (e.g. to the child controller 12).

In some embodiments, the input voltage range limiter need not be provided and, as such, the optocoupler driver circuit 23 is also not provided. In such embodiments, the output from the optocoupler 22 (e.g. N4) is connected to the input of the timer circuit 212 (e.g. N6). In such embodiments, the transmission of information across the optocoupler 22 may be slower than with these components. However, the drain of electrical power when the source (e.g. the parent controller 13) is not transmitting to the destination (e.g. the child controller 12) may be lower.

As depicted in figure 2, for example, the communication system 2 may include the optocoupler 22 located in series between the source and the destination (e.g. between the parent controller 13 and the child controller 12). The optocoupler driver circuit 23 may be communicatively coupled between the source and the destination (e.g. between the parent controller 12 and the child controller 12).

The information to be sent from the source (e.g. the parent controller 13) to the destination (e.g. the child controller 12) may be received as an input signal to the communication system 2. This signal may be communicated through the communication pathway and output as an output signal. As will be appreciated, the input signal may be detected and this used to determine whether or not to provide electrical power to the destination (e.g. to the child controller 13). Therefore, the destination (e.g. the child controller 13) may only be on when it is required and this may reduce the risk of failure.

Embodiments may be used in relation to battery systems 1 used in vehicles, for example, and this may include electric cars, trucks, lorries, motorcycles, bicycles, boats, ships, and the like.

With reference to figure 6, some embodiments include a return communication circuit 3. The return communication circuit 3 is configured to enable communication from the destination (e.g. the child controller 12) to the source (e.g. the parent controller 13). As will be understood, this communication circuit 3 may be used once the destination (e.g. the child controller 12) has been turned on as described herein.

With reference to figure 6, an output from the destination (e.g. the child controller 12) may be provided at, for example, N8. U3 may represent a constant voltage source. A predetermined voltage may be applied at N9.

N10 and N11 may be connectable to open-collector outputs of the source (e.g. the parent controller 13). This the part of the return communication circuit 3 may adapts the signal coming from the optocoupler 22 to compensate for battery voltage variation from the one or more associated batteries 11. N12 may be a listening communications port of the source (e.g. the parent controller 13). The return communication circuit 3 may include a comparator (e.g. U4).

As will be understood, the return communication circuit 3 may be very similar the circuits described in relation to the other communication pathway (which might be referred to as the initiating communication path, for example); however, in the return communication circuit 3 the active tuning elements may be kept on the source (e.g. parent controller 13) side so that the source (e.g. parent controller 13) has control over the send and receive. This may reduce cost and complexity as it may mean the (relatively larger number of) destinations (e.g. child controllers 12) do not need the management complexity.

As will be appreciated, in relation to the return pathway, the references to the source and destination have been retained from the initiating communication path described herein - for consistency. However, for the return communication pathway, information is sent from the destination (e.g. from the child controller 12) to the source (e.g. to the parent controller 13). When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.