Wireless system for battery management and corresponding method

Abstract

A wireless system (1) for battery management comprises slave management modules (3) which are coupled one-to-one to battery modules (2), and a master management module (5) paired with the slave management modules (3). The master management module (5) comprises a computer (6) configured to operate in an active mode and in a standby mode, and a control device (7) configured to communicate wirelessly with each slave management module (3). The control device (7) is configured to calculate a value of the time elapsed during the standby mode of the computer (6).

Description

[0001] TITLE: Wireless Battery Management System and Associated Method

[0002] Technical field

[0003] The invention relates to the technical field of power batteries for electric or hybrid traction vehicles, and in particular to systems for managing such batteries, in particular wireless management systems.

[0004] Previous techniques

[0005] Electric or hybrid traction vehicles use traction batteries to store the electrical energy needed for their operation.

[0006] Battery management systems are commonly used to monitor the condition of the batteries in these vehicles. Typically, these management systems require a significant amount of electrical connection cables to connect to the batteries. The use of cables increases the weight and cost of vehicles and imposes constraints related to the reliability of connections and battery design.

[0007] Wireless management systems have been developed to avoid the inconvenience of using cables.

[0008] Battery management systems are configured to make estimates of the calendar aging of batteries, for example, estimates of capacity loss and internal resistance increase based on the time since first use.

[0009] To get the elapsed time, there are mainly two methods.

[0010] A first method consists of integrating a dedicated electronic component into the battery management system, such as a real-time clock (RTC), which provides real time. This solution generates a significant cost.

[0011] A second method consists of obtaining the real time from a computer equipped with an RTC and which transmits this information at regular intervals to the battery management system via a CAN bus or "Controller Area Network" in English. However, any delay in the transmission of this information to the management system can cause malfunctions. Furthermore, this solution can cause significant excess consumption of electrical energy, because it is necessary to wake up the computer equipped with the RTC to obtain the real time and because transmission via CAN bus automatically wakes up all the computers connected to this bus.

[0012] Statement of the invention

[0013] The invention aims to provide a battery management system capable of determining the time elapsed since first use, which is economical in electrical energy and without using dedicated electronic components such as RTCs.

[0014] To this end, the invention relates to a wireless battery management system comprising slave management modules coupled in a one-to-one manner to battery modules, and a master management module associated with the slave management modules.

[0015] The master management module includes a computer configured to operate in an active mode and in a standby mode, and a controller configured to communicate wirelessly with each slave management module.

[0016] The controller is configured to calculate a value of the elapsed time in the computer's sleep mode.

[0017] Advantageously, the control device is provided with a logic output to which the computer is connected, so as to allow the computer to switch from a standby mode to an active mode when a voltage level of said logic output is set to a predetermined high voltage value.

[0018] For example, the voltage level of the logic output is set to the predetermined high voltage value when the elapsed time value exceeds a first predetermined time value. According to one feature, the computer and the control device are configured to communicate with each other through a serial type link.

[0019] Preferably, each battery module is configured to allow balancing of the electrical voltage across the terminals of the cells of the modules, based on a control signal from the control device when the value of the elapsed time exceeds a second predetermined time value.

[0020] According to another aspect, the invention relates to a battery management method comprising steps of:

[0021] - transmitting a reference time value from a calculator of the wireless battery management system corresponding to the time of transition to a standby mode of said calculator, storing the reference time value, and calculating a value of the time elapsed since the calculator entered standby mode based on a difference between a current time value and the stored reference time value.

[0022] For example, the method comprises an additional step of controlling the computer to switch to an active mode carried out when said value of the elapsed time exceeds a first predetermined time value.

[0023] Advantageously, the method comprises an additional step of updating the value of the reference time of the calculator carried out at the time of switching to an active mode of the calculator as a function of said value of the elapsed time.

[0024] Preferably, the method comprises an additional step of controlling the balancing of the voltage of at least one battery module, carried out when the value of the elapsed time exceeds a second predetermined time value.

[0025] According to another aspect, the invention relates to a hybrid or electric vehicle comprising a wireless battery management system or implementing a battery management method as described above.

[0026] Brief description of the drawings

[0027] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0028] [Fig 1] is a schematic view of a wireless battery management system according to one embodiment of the invention; and

[0029] [Fig 2] is a flowchart of a battery management method according to one embodiment of the invention.

[0030] Detailed description of at least one embodiment

[0031] Figure 1 is a schematic view of a wireless battery management system 1 according to one embodiment of the invention.

[0032] The wireless battery management system 1 comprises slave management modules 3 coupled in a one-to-one manner to battery modules 2. In other words, each slave management module 3 corresponds to a single battery module 2 and each battery module 2 corresponds to a single slave management module 3. Each battery module 2 comprises one or more electric accumulators (not shown), the battery modules 2 being connected in series and / or in parallel to form a battery 4. The battery 4 constitutes a source of electrical energy capable, for example, of powering an electric motor which at least partially provides traction for a vehicle. The use of the invention is not limited to the traction of electric vehicles and is also conceivable in the case of stationary applications.

[0033] Each slave management module 3 is configured to communicate with its associated battery module 2. This communication is carried out by wired means.

[0034] The slave management modules 3 are adapted for receiving data relating to the electrical voltage and / or the temperature of the associated electrical modules 2. Each battery module 2 is configured to allow balancing of the electrical voltage. The balancing of the electrical voltage is preferably done by dissipation through an electrical resistor (not shown) associated with each battery module 2, so as to balance the electrical voltages between the different battery modules 2.

[0035] System 1 also includes a master management module

[0036] 5 associated with the slave management modules 3. The master management module 5 monitors the state of the battery 4 in particular in relation to the voltage and / or temperature values ​​of each battery module 2.

[0037] The master management module 5 comprises a computer 6 and a control device 7. The control device 7 and the computer

[0038] 6 are configured to communicate with each other through a serial type 8 link.

[0039] The control device 7 is configured to control each slave management module 3. Preferably, the control is carried out wirelessly. The slave management modules 3 are also suitable for transmitting control signals from the device

[0040] 7 to the battery modules 2. Thus, the control device 7 is configured to control each battery module 2 through the associated slave management module 3.

[0041] The control device 7 comprises a computing module 7a, a memory module 7b and a wireless communication module 7c.

[0042] The computer 6 makes estimates of the aging of the battery 4, in particular in terms of loss of capacity and increase in internal resistance. To make these estimates, the computer uses the time elapsed since a reference time, for example the time elapsed since a first start-up or a first use of the system 1. This reference time is known and stored in a memory of the computer 6. The reference time is periodically updated to take into account the passage of calendar time.

[0043] The battery 4 provides the electrical power supply to the system 1. In order to preserve the autonomy of the battery 4, the computer 6 is configured to operate in an active mode and in a standby mode. The active mode is a mode that consumes electrical power in which the computer 6 is activated. The standby mode is a mode that consumes little electrical power in which the computer 6 is deactivated. The computer 6 is configured to switch from an active mode to a standby mode when it receives an instruction from a high-level control unit (not referenced).

[0044] The computer 6 comprises a stopwatch 6a. When the computer 6 operates in an active mode, the stopwatch 6a measures the passage of calendar time and the computer 6 updates the reference time according to the time value measured by the stopwatch 6a. The periodicity of the update in an active mode of the computer 6 has a predetermined value and is for example equal to one minute.

[0045] When the computer 6 is operating in a sleep mode, the stopwatch 6a is deactivated and cannot be used for updating the reference time.

[0046] The control device 7 is configured to calculate a value of the time elapsed since the computer 6 went into standby mode. For this purpose, the calculation module 7a is adapted to determine a current time value. The calculation module 7a increments a counter (or “timestamp” in English), for example by increasing it by 1 every millisecond.

[0047] The control device 7 is provided with a logic output 9 to which the computer 6 is connected, so as to allow the computer 6 to switch from a standby mode to an active mode when a voltage level of the logic output is set to a predetermined high voltage value.

[0048] The control device 7 is configured to set the voltage level of the logic output 9 to the predetermined high voltage value when the value of the elapsed time exceeds a first predetermined time value. With such a battery management system, it is therefore possible to control the waking up of the computer 6 through the device 7. In other words, it becomes possible to program in advance the waking up of the computer 6 by limiting the time spent in standby mode, via the device 7.

[0049] As indicated previously, it is advantageous to take advantage of these wake-up phases to update the balancing instructions in the device 7 and thus, each battery module 2 is configured to allow balancing of the electrical voltage.

[0050] The control device 7 is configured to control a balancing of the electrical voltage of the battery modules 2 by a control signal emitted when the value of the elapsed time exceeds a second predetermined time value. With such a battery management system, it becomes possible to control the balancing of the electrical voltage of the cells of the battery 2 via the device 7 even when the computer 6 is operating in a standby mode.

[0051] For example, the first time value may take a value between 6 a.m. and 8 a.m. Preferably, the second predetermined time value is less than the first. For example, the second predetermined time value may take a value between 2 and 4 hours. However, it is still possible for the second predetermined time value to be equal to the first.

[0052] Figure 2 is a flowchart of a battery management method according to one embodiment of the invention.

[0053] The method begins with a preliminary step 10 of detecting an instruction to switch to standby mode of a computer 6 of a wireless system 1 for managing a battery 4.

[0054] Following this instruction, the computer 6 transmits to the device 7 the value of the reference time corresponding to the moment of transition to a standby mode (step 1 1 ).

[0055] The method continues with a step 12 of storing the value of the reference time in the memory module 7b of the control device 7.

[0056] The calculation module 7a then calculates a value of the time elapsed since the computer 6 went into standby mode. The calculation is carried out as a function of the difference between a current time value determined by the calculation module 7a and the value of the reference time available from the memory module 7b (step 13). For example, the value of the reference time may come from a real-time clock connected to the control device 7.

[0057] The method continues with a step 13 of controlling the balancing of the voltage of at least one battery module 2. The balancing control step 13 is carried out when the value of the elapsed time exceeds a second predetermined time value.

[0058] The control device 7 sets the voltage level of the logic output 9 to the predetermined high voltage value when the value of the elapsed time exceeds a first predetermined time value, so as to cause the computer 6 to switch to an active mode (step 14).

[0059] In the next update step 15, the computer 6 updates the value of the reference time as a function of the value of the elapsed time. Thus, the value of the reference time is updated by adding the value of the reference time previously stored in a memory of the computer 6 and the value of the elapsed time calculated by the device 7.

[0060] It should be noted that the update step 15 is carried out after the computer 6 has switched to an active mode, also called wake-up, but that it is not necessary for this wake-up to be controlled by the device 7. For example, it is possible to carry out the update step 15 after a wake-up of the computer 6 controlled by a high-level control unit following a start-up carried out by a user.

[0061] In a possible variant embodiment, the method does not include a balancing control step 13 and the step 14 of controlling the computer to switch to an active mode is carried out directly after the storage step 12.

Claims

CLAIMS 1. Wireless battery management system (1) comprising slave management modules (3) coupled one-to-one to battery modules (2), and a master management module (5) associated with said slave management modules (3), said master management module (5) comprising a computer (6) configured to operate in an active mode and in a standby mode, and a control device (7) configured to communicate wirelessly with each slave management module (3), characterized in that said control device (7) is configured to calculate a value of the time elapsed in the standby mode of said computer (6).

2. System according to claim 1, wherein said control device (7) is provided with a logic output (9) to which said computer (6) is connected, so as to allow the computer (6) to switch from a standby mode to an active mode when a voltage level of said logic output (9) is set to a predetermined high voltage value.

3. The system of claim 2, wherein the voltage level of the logic output (9) is set to the predetermined high voltage value when the elapsed time value exceeds a first predetermined time value.

4. System according to any one of claims 1 to 3, wherein said computer (6) and said control device (7) are configured to communicate with each other via a serial type link (8).

5. System according to any one of claims 1 to 4, in which each battery module (2) is configured to allow balancing of the electrical voltage at the terminals of the cells of said modules, as a function of a control signal from the control device (7) when the value of the elapsed time exceeds a second predetermined time value.

6. Battery management method implemented by a system according to any one of claims 1 to 5, comprising steps of: - transmission of a reference time value from a computer (6) of the wireless battery management system (1) corresponding to the time of transition to a standby mode of said computer (6), storage of the reference time value, and calculation of a value of the time elapsed since transition to standby mode of said computer as a function of a difference between a current time value and the stored reference time value.

7. Method according to claim 6, comprising an additional step of controlling the computer (6) to switch to an active mode carried out when said value of the elapsed time exceeds a first predetermined time value.

8. Method according to claim 6 or 7, comprising an additional step of updating the value of the reference time of the computer (6) carried out at the time of switching to an active mode of the computer (6) as a function of said value of the elapsed time.

9. Method according to claim 6, comprising an additional step of controlling the balancing of the voltage of at least one battery module (2), carried out when the value of the elapsed time exceeds a second predetermined time value.

10. Hybrid or electric vehicle comprising a wireless battery management system according to any one of claims 1 to 5 or implementing a method according to any one of claims 6 to 9.

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