Battery protection system and battery

Abstract

Battery Protection System and Battery The present invention relates to a protection system (14) for a battery (10), the battery (10) comprising a plurality of modules (12) connected in parallel, the protection system (10) comprising: - a first disconnection device (28), the first disconnection device (28) comprising a contactor (32) having an open position in which the battery (10) is disconnected from all the modules (10) - a second disconnection device (30), the second disconnection device (30) being separate from the first disconnection device (28), the second disconnection device (30) comprising a switching element (40) specific to each module (12), each switching element (40) having an open position in which the module (12) is disconnected from the other modules (12) and from the battery (10). Figure for the abstract: Figure 2

Description

Title of the invention: Battery protection system and battery

[0001] The present invention relates to a battery protection system and a battery comprising such a protection system.

[0002] Typically, a battery comprises one or more current storage cells, also called electrochemical generators, cells, or elements. A battery is an electricity-producing device in which chemical energy is converted into electrical energy. The chemical energy comes from electrochemically active compounds deposited on at least one face of electrodes arranged in the battery. The electrical energy is produced by electrochemical reactions during a discharge of the battery. The electrodes, arranged in a container, are electrically connected to current output terminals that ensure electrical continuity between the electrodes and an electrical load to which the battery is connected.

[0003] To increase the electrical power delivered, several sealed accumulators can be connected together to form a battery. Thus, a battery can be divided into modules, each module being composed of one or more accumulators connected together in series and / or in parallel. For example, a battery may comprise one or more parallel branches of accumulators connected in series and / or one or more parallel branches of modules connected in series.

[0004] A charging circuit is generally provided to which the battery can be connected to recharge the accumulators.

[0005] Furthermore, an electronic management system comprising measurement sensors and an electronic control circuit, more or less sophisticated depending on the applications, can be associated with the battery.

[0006] Such a system makes it possible in particular to organize and control the charging and discharging of the battery, in order to balance the charging and discharging of the different accumulators of the battery with respect to each other.

[0007] In the event of battery malfunction, the management system also isolates the battery to prevent thermal runaway effects that could lead to a battery explosion.

[0008] For this purpose, the management system controls the opening and closing of a contactor positioned between the battery accumulators and the battery terminals.

[0009] However, this poses a safety problem since the contactor only opens if the control system commands it to do so. In particular, a failure of the control system can lead to a thermal runaway situation.

[0010] There is therefore a need for a protection system to protect the battery with improved safety.

[0011] For this purpose, the description relates to a battery protection system, the battery comprising a plurality of modules connected in parallel, the protection system comprising:

[0012] - a first disconnection device, the first disconnection device including a contactor with an open position in which the battery is disconnected from all modules,

[0013] - a second disconnection device, the second disconnection device being distinct from the first disconnection device, the second disconnection device comprising a cutting element specific to each module, each cutting element having an open position in which the module is disconnected from the other modules and the battery.

[0014] According to other advantageous aspects, the protection system includes one or more of the following characteristics, taken individually or according to all technically possible combinations: - each cutting element is capable of passing irreversibly from a closed position to an open position.

[0015] - each switching element is a pyrotechnic switch.

[0016] - the first disconnection device includes a controller for controlling the contactor position.

[0017] - the protection system further comprises a set of sensors specific to the battery, the controller controlling the position of the contactor based on measurements from the battery's own sensor set.

[0018] - the second disconnection device includes a control unit specific to check the position of each cutting element.

[0019] - for each switching element, the control unit is specific to control only the transition from the closed position to the open position.

[0020] - the protection system further comprises a set of its own sensors For each module, the control unit controls the position of each switching element based on measurements from the set of sensors specific to each module.

[0021] - the control unit is also suitable for controlling the position of the contactor.

[0022] - the control unit is designed to control only the transition of the position closed of the contactor to the open position of the contactor.

[0023] - the control unit is a set of logic components.

[0024] The description also relates to a battery comprising a protection system as previously described.

[0025] The description also relates to a vehicle comprising a battery as previously described, the vehicle being chosen from the list consisting of an aircraft, a means of rail transport, a means of road transport, a means of maritime or river transport.

[0026] In this description, the expression "specific to" means interchangeably "suitable for", "adapted to" or "configured for".

[0027] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0028] - [Fig. 1] [Fig. 1] is a schematic representation of a battery equipped with a protection system, and

[0029] - [Fig.2] [Fig.2] is a schematic representation of the protection system of the [Fig.l].

[0030] A battery 10 is shown in [Fig.1].

[0031] In a manner known per se, a battery comprises a plurality of modules 12 and a protection system 14.

[0032] Without being limiting, three modules 12 are represented on the [Fig.1].

[0033] Each module 12 can comprise one or more electrochemical elements in a series, parallel or more complex arrangement.

[0034] As explained previously, an electrochemical element is an electricity-producing device in which chemical energy is converted into electrical energy.

[0035] Each electrochemical element therefore delivers a current and a voltage between two terminals.

[0036] Due to the arrangement of the electrochemical element(s), the module 12 is thus configured to deliver a current and a voltage between a first terminal 16 and a second terminal 18.

[0037] The first terminals 16 are connected to a terminal 22 of the battery 10 while the second terminals are connected to another terminal 20 of the battery 10.

[0038] The modules 12 are thus connected in parallel.

[0039] Each module 12 is, in addition, equipped with a first set 24 of sensors.

[0040] The first set 24 is a local set in the sense that it is specific to a module 12.

[0041] For example, the sensors of the first set 24 are a temperature sensor of module 12, a voltage sensor between the first terminal 16 and the second terminal 18 and a sensor of the electric current delivered by module 12.

[0042] Battery 10 also includes a second set 26 of sensors.

[0043] The second set 26 is a global set in the sense that it is specific to the behavior of the entire battery 10.

[0044] For example, the sensors of the second set 26 are a temperature sensor of the battery 10, a voltage sensor between the two terminals 20 and 22 of the battery 10 and a sensor of the electric current delivered by the battery 10.

[0045] The second set 26 is therefore distinct from the first set 24.

[0046] According to a particular example, battery 10 is a power supply on board a vehicle.

[0047] According to one embodiment, the vehicle is chosen from the list consisting of an aircraft, a means of rail transport, a means of road transport, a means of maritime or river transport.

[0048] The protection system 14 is interposed between the terminals 20 and 22 of the battery 10 and the modules 12.

[0049] The protection system 14 has the role of protecting the battery 10, that is to say, securing it, in the presence of abnormal behavior of one or more of the modules 12.

[0050] In particular, the protection system 14 protects the battery 10 against overcharging, over-discharging, over-temperature and over-current.

[0051] The elements of the protection system 14 are visible more precisely on the [Fig.2],

[0052] The protection system 14 includes a first disconnection device 28 and a second disconnection device 30.

[0053] The first disconnection device 28 comprises a contactor 32 and a controller 34.

[0054] The contactor 32 is a controlled electronic component used to open or close a connection between two elements.

[0055] The contactor 32 thus has an open position and a closed position.

[0056] The contactor 32 is positioned between the second disconnecting device 30 and terminal 20 or 22 of battery 10.

[0057] In the open position, no current is delivered at the output of battery 10.

[0058] By way of example, the contactor 32 is a semiconductor contactor.

[0059] A semiconductor contactor is more often designated by the abbreviation SSR, which refers to the corresponding English term "solid-state relay," generally translated as contactor or static relay.

[0060] Such a contactor is a circuit allowing a connection between two elements to be opened or closed without the use of a mechanical or electromechanical element.

[0061] The contactor 32 is here formed of one or more transistors.

[0062] Here, the contactor 32 comprises two transistors mounted back-to-back.

[0063] In addition, each transistor is an insulated-gate field-effect transistor.

[0064] Such a transistor is more often called a MOSFET transistor.

[0065] The acronym MOSFET refers to the English name "metal-oxide-semiconductor field-effect transistor" which can be literally translated as "metal-oxide-semiconductor field-effect transistor".

[0066] In more elaborate variants, the first disconnection device 28 comprises several contactors.

[0067] The controller 34 is designed to control the position of the contactor 32.

[0068] For this purpose, the controller 34 sends a control law towards the contactor 32, schematically represented by an arrow 36 in dotted lines on [Fig.2].

[0069] The controller 34 determines the control law based on the measurements taken by the second set 26 of sensors (the one which relates to the battery 10 as a whole).

[0070] This means that the controller 34 obtains the measurement values ​​from the second set 26. This is schematically represented by three solid-lined arrows 38 in [Fig. 2]. The number three was chosen to illustrate the common case where the three measurements are temperature, voltage, and current.

[0071] As a simple illustration, the control law can correspond to a threshold, namely that when the value of a quantity exceeds a threshold, the switch to the open position is imposed on the contactor 32.

[0072] In the example described, the control law is reversible in the sense that if the condition is no longer met, the contactor 32 returns to the closed position.

[0073] The controller 34 is here an intelligent system in the sense that the controller 34 includes a processor.

[0074] For example, controller 34 is a microcontroller, the processor then being a microprocessor.

[0075] The second disconnection device 30 comprises a switching element 40 for each module and a control unit 42.

[0076] Each switching element 40 is thus connected at one end to a terminal of the contactor 32 and at the other end to the first terminal 16 of the module 12.

[0077] The cutting elements 40 are thus arranged in parallel.

[0078] According to the example in [Fig.2], each switching element 40 is a pyrotechnic switch.

[0079] A pyrotechnic switch is a switch that operates in two positions, an open position and a closed position.

[0080] In the open position, the associated module 12 is no longer connected to the contactor 32.

[0081] The pyrotechnic switch is irreversible, so that it can only move from the closed position to the open position. This opening is achieved by cutting the conductive material using a pyrotechnic device.

[0082] With reference to the corresponding English name, such a switching device 40 is often referred to as a pyro-switch.

[0083] The control unit 42 is a set of discrete logic and electronic components.

[0084] This is intended to limit the number of failures that may occur in the control unit 42.

[0085] Alternatively, the control unit 42 is implemented in the form of a programmable logic component, such as an FPGA (Field Programmable Gate Array).

[0086] The control unit 42 is designed to control the position of each of the cutting elements 40.

[0087] This control is shown by arrows 44.

[0088] In the described embodiment, the switching elements 40 irreversibly transition from the closed position to the open position. The control of the control unit 42 is therefore limited here solely to controlling the opening of each switching element 40, that is, the transition of each switching element 40 from the closed position to the open position.

[0089] The control can be individualized, so that only one of the cutting members 40 can change position while the others remain in the same position.

[0090] This makes it possible in particular to isolate a faulty module 12 from the other modules 12 that are still functional.

[0091] The control unit 42 is thus configured to provide local control.

[0092] To determine the appropriate position of the cutting element 40, the control unit 40 relies on measurements from the first set 24 of each module 12.

[0093] This is schematically represented on [Fig.2] by the three arrows 46, each corresponding to data from a first respective set 24.

[0094] The control unit 42 is also suitable for controlling the movement of the contactor 32 to the open position.

[0095] This control is schematically illustrated by arrow 48.

[0096] The control unit 32 operates independently of the controller 34 of the first disconnection device 28.

[0097] This means that the contactor 32 of the first disconnecting device 28 can be closed only if the control unit 42 does not request its opening and if the controller 34 requests its closing.

[0098] The control of the control unit 42 is thus a redundant control in relation to that already carried out by the controller 34, so that it provides additional security to the protection system 14.

[0099] This safety is reinforced by the fact that the control unit 42 has an irreversible operation, whether for the cutting elements 40 or for the contactor 32.

[0100] This irreversible operation results in the fact that the control unit 42 only controls the opening of the cutting elements 40 and the contactor 32.

[0101] The protection system just described thus makes it possible to obtain good safety for the battery 10 in particular thanks to the independence of the two disconnection devices 28 and 30.

[0102] This independence has two aspects.

[0103] According to a first aspect, the state of the first disconnecting device 28 (contactor 32 in open or closed position) and the state of the second disconnecting device 30 (switching elements 40 in open or closed position) are mainly controlled by a separate entity (the control unit 34 for the former and the controller 42 for the latter). The states of the two disconnecting devices 28 and 30 can therefore differ.

[0104] According to a second aspect, the first disconnection device 28 and the second disconnection device 30 operate independently, that is to say, it is sufficient for one of the two disconnection systems 28 and 30 to be in a disconnected state for the battery 10 to be disconnected.

[0105] In this case, this aspect is reinforced by the fact that the first disconnection device 28 and the second disconnection device 30 are connected in series.

[0106] In fact, the two disconnection devices 28 and 30 are mounted in series in such a way that the current flowing from the modules 12 to the terminals 20 and 22 of the battery 10 can be interrupted independently by either of the disconnection devices 28 or 30.

[0107] The protection system 14 allows the connection and disconnection of the battery 10 to be managed during operational phases, but also to protect the battery 10 and more particularly the modules 12 from internal short circuits, overcharges, overdischarges, over-temperatures and over-currents.

[0108] The protection system 14 achieves a high level of safety by providing good reliability and a low failure rate. Reliability is further enhanced by the presence of two control entities manufactured using different technologies.

[0109] The protection system 14 also makes it possible to do without fuses since each disconnection device 28 or 30 performs its own current measurement and can interrupt the current flow redundantly.

[0110] Other embodiments of the protection system 14 are conceivable.

[0111] According to a first example, the controller 34 is the computer of the battery management system 10.

[0112] Such a management system is more often designated BMS, the abbreviation referring to the corresponding English term "Battery Management System".

[0113] In such a case, the first disconnection device 28 is part of the management system.

[0114] As an alternative or in addition, the contactor 32 can be made according to a different technology.

[0115] Similarly, each cutting element 40 can be replaced by a cutting element of a reversible nature.

[0116] For example, each switching element 40 can be an SSR contactor or an electromechanical contactor.

[0117] The protection system 14 may also include additional components to add functionalities or to enhance the level of security it provides.

Claims

Demands

1. A protection system (14) for a battery (10), the battery (10) comprising a plurality of modules (12) connected in parallel, the protection system (10) comprising: - a first disconnection device (28), the first disconnection device (28) comprising a contactor (32) having an open position in which the battery (10) is disconnected from all the modules (10) - a second disconnection device (30), the second disconnection device (30) being separate from the first disconnection device (28), the second disconnection device (30) comprising a switching element (40) specific to each module (12), each switching element (40) having an open position in which the module (12) is disconnected from the other modules (12) and from the battery (10).

2. A protection system according to claim 1, wherein each cutting member (40) is adapted to pass irreversibly from a closed position to an open position.

3. Protection system according to claim 2, wherein each breaking member (40) is a pyrotechnic switch.

4. A protection system according to any one of claims 1 to 3, wherein the first disconnection device (28) includes a controller (34) for controlling the position of the contactor (32).

5. Protection system according to claim 4, wherein the protection system (14) further comprises a set (26) of sensors specific to the battery (10), the controller (34) controlling the position of the contactor (32) as a function of measurements from the set of sensors (26) specific to the battery (10).

6. A protection system according to any one of claims 1 to 5, wherein the second disconnecting device (30) comprises a control unit (42) adapted to control the position of each cutting member (40).

7. A protection system according to claim 6, wherein, for each cutting element (40), the control unit (42) is suitable for controlling only the transition from the closed position to the open position.

8. Protection system according to claim 6 or 7, wherein the protection system (14) further comprises a set (24) of sensors specific to each module (12), the control unit (42) controlling the position of each breaking element (40) according to measurements of the set (24) of sensors specific to each module (12).

9. A protection system according to any one of claims 6 to 8, wherein the control unit (42) is also suitable for controlling the position of the contactor (32).

10. Protection system according to claim 9, wherein the control unit (42) is adapted to control only the transition from the closed position of the contactor (32) to the open position of the contactor (32).

11. A protection system according to any one of claims 6 to 10, wherein the control unit (42) is a set of logic components.

12. Battery (10) comprising a protection system (14) according to any one of claims 1 to 11.

13. Vehicle comprising a battery (10) according to claim 12, the vehicle being selected from the list consisting of an aircraft, a means of rail transport, a means of road transport, a means of maritime or river transport.

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