PROTECTION SYSTEM FOR A BATTERY SYSTEM DESIGNED TO DELIVER POWER TO A LOAD, AND METHOD FOR OPERATING THE PROTECTION SYSTEM

Abstract

Protection system (144) for a battery system (104) designed to supply power to a load (216), wherein the protection system (144) comprises: a battery control module (136) configured to open at least one contactor (208) for isolating the battery system (104) from the load (216) only when a detected current (i) is greater than a first threshold and (ii) is within a first current range; at least one fuse (212) connected between a first terminal (232) and a second terminal (236) of the battery system (104), wherein the at least one fuse (212) is configured to open in response to the detected current (i) being greater than a second threshold which is greater than the first threshold, and (ii) being in a second current range which is greater than and offset from the first current range, isolating the battery system (104) from the load (216); and an auxiliary protection module (244) configured to form a short circuit between the first terminal (232) and the second terminal (236) in response to the detected current being (i) greater than the first threshold, (ii) less than the second threshold, and (iii) within a coverage gap range defined by a current lower limit and a current upper limit between the first current range and the second current range; where the lower current limit is equal to the upper end of the first current range.

Description

INTRODUCTION

[0001] The present invention relates to vehicles and in particular to a protection system for a battery system designed to deliver power to a load, and to a method for operating the protection system.

[0002] A protection system for a battery system, designed to supply power to a load for the protection of the battery system, is described, for example, in DE 10 2006 054 354 A1. Further prior art is described in US 2013 / 0 308 356 A1 and DE 11 2014 000 548 T5.

[0003] Some types of vehicles contain only an internal combustion engine that generates drive torque. Pure electric vehicles contain a battery system and an electric motor. Hybrid vehicles contain both an internal combustion engine and one or more electric motors and may include a battery system. The battery system contains one or more batteries or one or more battery modules. Each battery module contains one or more battery cells. SUMMARY

[0004] According to the invention, a protection system for a battery system designed to deliver power to a load is presented, wherein the protection system is characterized by the features of claim 1.

[0005] According to further characteristics, the at least one contactor contains a first contactor connected to the first terminal and a second contactor connected to the second terminal.

[0006] According to further characteristics, the load comprises multiple loads.

[0007] According to further features, the protection system also includes at least one current sensor, wherein the auxiliary protection module receives the detected current from the at least one current sensor.

[0008] According to further features, the auxiliary protection module is configured to selectively form the short circuit based on the detected current, a lower current limit and a higher current limit.

[0009] According to further characteristics, the current limit is less than or equal to the second threshold.

[0010] According to further features, the auxiliary protection module contains a gate control circuit and a switch, and the gate control circuit is configured to selectively close the switch to form the short circuit based on the detected current, the lower current limit and the upper current limit.

[0011] According to further characteristics, the switch is a controlled silicon rectifier and is an output of the gate control circuit connected to a gate of the controlled silicon rectifier.

[0012] According to further features, the gate control circuit includes a first comparator that takes the detected current and the current upper limit, a second comparator that takes the detected current and the current lower limit, and an AND gate that takes the outputs of the first comparator and the second comparator.

[0013] According to further features, the auxiliary protection module contains a resistor that is connected in series with the switch.

[0014] According to further characteristics, a vehicle contains the protection system.

[0015] Furthermore, according to the invention, a method for operating a protection system for a battery system designed to deliver power to a load is presented, wherein the method is characterized by the features of claim 8.

[0016] According to further features, the method also includes controlling a switch based on the detected current, the lower current limit and the upper current limit to form the short circuit.

[0017] According to further characteristics, the switch is a controlled silicon rectifier.

[0018] Further features include controlling the switch using a gate control circuit configured as a window comparator, responding to the detected current, the current lower limit, and the current upper limit.

[0019] Further applications of the present invention will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples serve only for illustration. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be more fully understood from the detailed description and the accompanying drawings; these show: Fig. 1 a functional block diagram of an example vehicle system according to the present invention; Fig. 2A and Fig. 2B Functional block diagrams of an example battery system and protection system according to the present invention; Fig. 2C an example auxiliary protection module according to the present invention; Fig. 2D an example gate control circuit of the auxiliary protection module and Fig. 3 steps of an example procedure for operating the auxiliary protection module.

[0021] Reference symbols can be used multiple times in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0022] Electric or hybrid electric vehicles typically contain one or more rechargeable batteries or battery modules, each containing multiple battery cells (arranged, for example, in one or more battery assemblies). In some examples, an electric vehicle includes a high-voltage battery assembly (HV battery assembly) configured to supply electrical power to a motor via an inverter. A protection system may be configured to selectively isolate the battery assembly from other vehicle components, such as the inverter, a DC-DC converter, the motor, and other vehicle loads. For example, the protection system may include one or more contactors and one or more fuses, each configured independently to isolate the battery assembly in response to the detection of a fault condition, such as a current spike.

[0023] In certain examples, the contactors and fuses may have a coverage gap. For instance, the contactors may be configured to respond to relatively lower detected currents (e.g., currents exceeding an initial threshold and within a first current range) and have a relatively shorter (i.e., faster) response time. The contactors may include two contactors configured to open synchronously in response to a detected current exceeding the first threshold.

[0024] Conversely, the fuses can be configured to respond to relatively larger currents (e.g., currents that exceed a second threshold, which is larger than the first threshold, and the first current range, and are within a second current range). The second current range is larger than and separated from the first current range. A gap between the first and second current ranges is called a coverage gap range. For example, under certain conditions, one or more contactors may not need to open quickly enough in response to a current spike that (i) exceeds the first threshold and the first current range, but (ii) has not yet exceeded the second threshold. In other words, the current may increase in a way that, for a period while the current is within the coverage gap range (e.g., a coverage gap period), does not cause either the contactors or the fuses to open.

[0025] Battery management systems and methods according to the present invention implement a secondary or auxiliary protection module that responds to currents in the cover gap region. For example, the auxiliary protection module is configured to detect currents in the cover gap region and selectively trip one or more of the fuses (e.g., to open or blow them). In one example, the auxiliary protection module is configured to create a short circuit to trip the fuse using a clamping circuit arrangement (e.g., a clamping circuit arrangement based on a controlled silicon rectifier (SCR)). The auxiliary protection module is specifically configured to respond to currents in the cover gap region.

[0026] Although the principles of the present invention are described here in relation to vehicle batteries (e.g. rechargeable batteries for electric or hybrid vehicles), they can be applied to batteries used in non-vehicle applications.

[0027] With reference to Fig. Figure 1 shows a functional block diagram of an example vehicle system 100, which includes a battery assembly or battery system 104 according to the present invention. The vehicle system 100 can correspond to an autonomous or a non-autonomous vehicle. The vehicle can be an electric vehicle (as shown). According to further examples, the principles of the present invention can be implemented in a hybrid electric vehicle or a non-vehicle application.

[0028] A vehicle control module 112 controls various operations of the vehicle system 100 (e.g., acceleration, braking, etc.). The vehicle control module 112 can communicate with a transmission control module 116 to coordinate, for example, gear changes in a transmission 120. The vehicle control module 112 can communicate with the battery system 104 to coordinate, for example, the operation of an electric motor 128. While the example of one electric motor is provided, multiple electric motors can be implemented. The electric motor 128 can be a permanent magnet electric motor, an induction motor, or another suitable type of electric motor that outputs a voltage based on an electromagnetic counterforce (EMF) when freely rotating, such as a direct current electric motor (a DC electric motor) or an electric synchronous motor.In various implementations, different functions of the vehicle control module 112 and the transmission control module 116 can be integrated into one or more modules.

[0029] Electrical power is applied from the battery system 104 to the electric motor 128 to cause the electric motor 128 to output positive torque. For example, the vehicle control module 112 may include an inverter or inverter module (not shown) to apply electrical power from the battery system 104 to the electric motor 128. The electric motor 128 can output torque, for example, to an input shaft of the transmission 120, to a drive shaft of the transmission 120, or to another component. A clutch 132 may be implemented to couple the electric motor 128 to the transmission 120 and to decouple the electric motor 128 from the transmission 120.One or more transmission devices can be implemented between an output of the electric motor 128 and an input of the gearbox 120 to provide one or more predetermined transmission ratios between a rotation of the electric motor 128 and a rotation of the input of the gearbox 120.

[0030] A battery control module (including, for example, a vehicle or battery management system) 136 is configured to control functions of the battery system 104, which include controlling the switching of individual battery modules or cells of the battery system 104, monitoring operating parameters, diagnosing faults, etc. The battery control module 136 can also be configured to communicate with a telematics module 140.

[0031] A protection system 144 is located between the battery system 104 and the motor 128 and other loads (which are in Fig. (not shown in Figure 1) of the vehicle system 100 is provided. The protection system 144 is configured to selectively isolate the battery system 104 from the motor 128 and other loads. For example, the protection system 144 includes one or more contactors (e.g., a response to the battery control module 136), one or more fuses, etc., each configured to isolate or disconnect the battery system 104 in response to the detection of a fault condition, such as the detection that a current output by the battery system 104 exceeds a predetermined threshold. The protection system 144 according to the present invention is further configured (e.g., using an auxiliary protection module or APM) to detect and respond to a current in a cover gap area between the contactors and the fuses.

[0032] Fig. 2A and Fig. Figure 3B shows an example implementation of the battery system 104, the battery control module 136, and the protection system 144 according to the present invention. The battery system 104 contains several battery modules 200. In certain examples, each of the battery modules 200 can consist of several individual battery cells.

[0033] Each of the battery modules 200 can contain a corresponding management module (MM) 204. Each management module 204 is configured to monitor the operating characteristics (e.g., voltage, current, temperature, etc.) of its respective battery module 200. The management modules 204 communicate data specifying the monitored operating characteristics to the battery control module 136 (e.g., via a wireless communication interface). In some examples, the management modules 204 communicate with a master management module (not shown), which in turn communicates with the battery control module 136.

[0034] The protection system 144 includes contactors 208 (e.g., a first and a second contactor 208-1 and 208-2, respectively) and one or more fuses 212. When the contactors 208 are closed, current is supplied from the battery system 104 to loads 216, such as one or more motor generator units (MGUs) 220, a DC converter 224, and / or other loads 228. For example, the battery control module 136 controls the opening and closing of the contactors 208.

[0035] In one example, the battery control module 136 is configured to open the contactors 208 in response to a detected current exceeding a first threshold and being within a first current range, thus isolating the battery system 104 from the loads 216. For example, the detected current corresponds to a current flowing from a first terminal 232 of the battery system 104 through contactor 208-1, the loads 216, and contactor 208-2 to a second terminal 236 of the battery system 104, and being detected by a first current sensor 240. Conversely, the fuses 212 are configured to open (i.e., trip) in response to a current flowing from the battery system 104 that exceeds a second threshold, which is greater than the first threshold, and is within a second current range.

[0036] An auxiliary protection module (APM) 244 according to the present invention is configured to disconnect the battery system 104 in response to detected currents in a coverage gap region between the first current range and the second current range. In other words, the APM 244 responds to a current that is greater than the first threshold and the first current range, but not greater than the second threshold. For example, as shown, the APM 244 is connected between the first terminal 232 and the second terminal 236 (e.g., in parallel with the loads 216 and in series with one or more fuses 212). A second current sensor 248 detects current flowing between the first terminal 232 and the second terminal 236 and through one or more of the loads 216 and the respective fuses 212. As shown in Fig. As shown in Figure 2B, the APM 244 and the second current sensor 248 are connected to a main fuse 252, which is connected between the loads 216 and the second terminal 236.

[0037] The APM 244 is configured to selectively create a short circuit between the first terminal 232 and the second terminal 236 to blow one or more of the fuses 212 (or the main fuse 252 in Fig. 2B) in response to the fact that the current detected by the second current sensor 248 is in the coverage gap region. For example, the APM 244 includes a clamping circuit arrangement (e.g., a clamping circuit arrangement based on a controlled silicon rectifier (SCR)) that forms the short circuit. Although it is in Fig. The APM 244 is shown connected only to fuse 212, which corresponds to MGU 220. The APM 244 can be connected to multiple fuses 212, two or more APMs 244 can be connected to their respective fuses 212, and so on.

[0038] Fig. Section 2C shows an example of the APM 244 in more detail. The APM 244 contains a clamping resistor (R). crowbarThe second current sensor 248 and the main fuse 252 are connected in series between the first terminal 232 and the second terminal 236. The terminal resistor 256 is configured to act as a current-limiting resistor to limit the current through the main fuse 252. In other words, when the APM 244 closes the switch 260 to create a short circuit between the first terminal 232 and the second terminal 236, the terminal resistor 256 is configured to reduce the overall resistance between the first terminal 232 and the second terminal 236, allowing sufficient current to flow to trip the main fuse 252 without exceeding a desired current limit. According to other examples, the switch 260 can be configured to limit current, and the terminal resistor 256 can be omitted.

[0039] As shown, switch 260 is a controlled silicon rectifier (SCR), but other suitable switches can be used. In this example, the current detected by the second current sensor 248 is supplied to a gate control circuit 264. An output from the gate control circuit 264 (e.g., a gate control signal) is supplied to a gate of switch 260. The gate control circuit 264 is configured to close (i.e., short-circuit) switch 260 in response to the detected current being within a predetermined current range corresponding to the coverage gap range.

[0040] Fig. Figure 2D shows an example implementation of the gate control circuit 264. In this example, the gate control circuit 264 is configured as a window comparator. The gate control circuit 264 includes a first comparator 268, a second comparator 272, and an AND gate 276. The first comparator 268 takes the current passing through the second current sensor 248 (I sense ) is recorded, and a current limit (I upper ) (e.g., at an inverting terminal or a non-inverting terminal). The second comparator 272 records the current detected by the second current sensor 248 and a lower current limit (I). lower ) (e.g., in the case of a non-inverting or an inverting connection). The AND gate 276 outputs the gate control signal based on the outputs of the first comparator 268 and the second comparator 272.

[0041] The lower and upper current limits correspond to the lower and upper limits of the coverage gap range. For example, the lower current limit is chosen to be greater than or greater than any possible output current of the battery system 104 during normal (i.e., non-fault) operation. As an example, the lower current limit is to be greater than the first threshold at which the contactors 208 are configured to open, and greater than the first current range covered by the contactors 208. For example, the lower current limit is located at or above the upper end of the first current range. Conversely, the upper current limit is chosen to be less than or equal to the second current range at which the main fuse 252 (and / or the fuses 212) are configured to open. For example, the upper current limit is less than or equal to the second threshold at which the fuses 212 and / or the main fuse 252 are configured to open.

[0042] Accordingly, the gate control circuit 264 is configured to close the switch 260 to form the short circuit only when the detected current is within the coverage gap range. In other words, when the detected current is greater than the first threshold and less than the current lower limit (i.e., within the first current range), the gate control circuit 264 does not control the switch 260 to form the short circuit and instead allows the contactors 208 to open to disconnect the battery system 104. Conversely, when the detected current is greater than the current upper limit and the second threshold (i.e., within the second current range), the gate control circuit 264 allows the fuses 212 and / or the main fuse 252 to trip to disconnect the battery system 104.

[0043] Fig.Figure 3 shows an example procedure 300 for operating the protection system 144. In Figure 304, the procedure 300 (e.g., the second current sensor 248) detects the current output by the battery system and flowing between the first terminal 232 and the second terminal 236. In Figure 308, the procedure 300 (e.g., the battery control module 136 and / or the APM 244) determines whether the detected current is greater than the first threshold. If so, the procedure continues to Figure 312. If not, the procedure 300 continues to Figure 304.

[0044] In 312, procedure 300 (e.g., the battery control module 136 and / or the APM 244) determines whether the detected current is outside the first current range (i.e., greater than it). For example, procedure 300 determines whether the detected current is greater than the current lower limit of the APM 244 and therefore outside the first current range of the contactors 208. If yes, procedure 300 continues to 316. If no, procedure 300 continues to 320. In 320, procedure 300 (e.g., the battery control module 136) opens the contactors to isolate the battery system 104 from the loads 216.

[0045] In section 316, procedure 300 (e.g., APM 244) determines whether the detected current is greater than the current limit. In other words, procedure 300 determines whether the detected current in the coverage gap area is outside the second current range of the fuses (e.g., fuses 212 and / or the main fuse 252) (i.e., less than it). If the detected current is greater than the current limit, procedure 300 continues to 324. If not, procedure 300 continues to 328. In 328, the method 300 (e.g., the APM 244) forms a short circuit across the first terminal 232 and the second terminal 236. For example, the APM 244 actuates the switch 260 to allow a current sufficient to trip the main fuse 252 to flow between the first terminal 232 and the second terminal 236.

[0046] In 324, the method 300 allows the main fuse 252 (and / or the fuses 212) to trip without closing the switch 260 to create the short circuit. In other words, since the detected current is in the second current range (i.e., a coverage area of ​​the fuses), the fuses trip to isolate the battery system 104 from the loads 216.

Claims

[1] Protection system (144) for a battery system (104) designed to supply power to a load (216), the protection system (144) comprising: a battery control module (136) configured to open at least one contactor (208) for isolating the battery system (104) from the load (216) only when a detected current (i) is greater than a first threshold and (ii) is within a first current range; at least one fuse (212) connected between a first terminal (232) and a second terminal (236) of the battery system (104), wherein the at least one fuse (212) is configured to open in response to the detected current (i) being greater than a second threshold which is greater than the first threshold, and (ii) being in a second current range which is greater than and offset from the first current range, isolating the battery system (104) from the load (216); and an auxiliary protection module (244) configured to form a short circuit between the first terminal (232) and the second terminal (236) in response to the detected current being (i) greater than the first threshold, (ii) less than the second threshold, and (iii) within a coverage gap range defined by a current lower limit and a current upper limit between the first current range and the second current range; where the lower current limit is equal to the upper end of the first current range. [2] Protection system (144) according to claim 1, wherein the at least one contactor (208) comprises a first contactor (208-1) connected to the first terminal (232) and a second contactor (208-2) connected to the second terminal (236). [3] Protection system (144) according to claim 1, which further comprises at least one current sensor (240, 248), wherein the auxiliary protection module (244) receives the detected current from the at least one current sensor (240, 248). [4] Protection system (144) according to claim 3, wherein the auxiliary protection module (244) is configured to form the short circuit based on the detected current, the lower current limit and the upper current limit. [5] Protection system (144) according to claim 1, wherein the current limit is less than or equal to the second threshold. [6] Protection system (144) according to claim 3, wherein the auxiliary protection module (244) includes a gate control circuit (264) and a switch (260) and wherein the gate control circuit (264) is configured to close the switch (260) to form the short circuit based on the detected current, the lower current limit and the upper current limit. [7] Protection system (144) according to claim 6, wherein the switch (260) is a controlled silicon rectifier and an output of the gate control circuit (264) is connected to a gate of the controlled silicon rectifier and / or the gate control circuit (264) includes a first comparator (268) that receives the detected current and the current upper limit, a second comparator (272) that receives the detected current and the current lower limit, and an AND gate (276) that receives outputs of the first comparator (268) and the second comparator (272), and / or the auxiliary protection module (244) includes a resistor (256) that is connected in series with the switch (260). [8] Method for operating a protection system (144) for a battery system (104) designed to supply power to a load (216), the method comprising: Opening at least one contactor (208) to isolate the battery system (104) from the load (216) only if a detected current (i) is greater than a first threshold and (ii) is within a first current range; Trip at least one fuse (212) connected between a first terminal (232) and a second terminal (236) of the battery system (104) in response to the detected current (i) being greater than a second threshold which is greater than the first threshold, and (ii) being in a second current range which is greater than and offset from the first current range, isolating the battery system (104) from the load (216); and Forming a short circuit between the first terminal (232) and the second terminal (236) in response to the detected current being (i) greater than the first threshold, (ii) less than the second threshold, and (iii) within a coverage gap region defined by a current lower limit and a current upper limit between the first current range and the second current range, wherein the current lower limit is greater than or equal to an upper limit of the first current range and the current upper limit is less than or equal to the second threshold.

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