Sensors for battery protection

Abstract

The battery assembly includes a housing, an outgassing sensor within the housing, a pressure relief device within the housing, the pressure relief sensor within the housing, and a processor within the housing. The outgassing sensor is configured to sense an outgassing event of one or more battery cells within the housing and output a first sensing signal. The pressure relief device is configured to release gas pressure from the housing in response to pressure within the housing exceeding a threshold. The pressure relief sensor is configured to sense a pressure relief event caused by the pressure relief device and output a second sensing signal. The processor is configured to receive the first sensing signal and the second sensing signal and transmit information related to the first and second sensing signals to a system external to the housing.

Description

[Technical Field]

[0001]

[0001] The present disclosure relates generally to battery technology, and more particularly to sensors for the protection of battery packs. [Background technology]

[0002]

[0002] Lithium-ion batteries, or Li-ion batteries, are a type of rechargeable battery that has a high energy density and generally has no memory effect. Batteries can be used individually or in groups packaged together in battery packs. Li-ion batteries and battery packs are commonly used in, for example, portable electronic devices (e.g., cell phones), electric vehicles, and consumer cordless power tools. Li-ion batteries are also used in military and aerospace applications.

[0003] Lithium-ion cells provide electrical current when lithium ions move from the negative electrode to the positive electrode through an electrolyte. Lithium ions move in the reverse direction when the cell is charged. In some examples, the positive electrode includes lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), or lithium manganese oxide (LiMn2O4 or Li2MnO3). The negative electrode typically includes graphite. The electrolyte may be a mixture of an organic carbonate and a lithium ion complex. For example, the electrolyte may include ethylene carbonate or diethyl carbonate. Lithium-ion cells can have a variety of form factors, including cylindrical, flat, pouch, and hard plastic cases with threaded terminals. In one example, a cylindrical lithium-ion cell typically includes a metal container that provides the primary structure to the cell and functions as the negative electrode. The container can be made of aluminum or steel. The electrode assembly includes current collector sheets separated by a porous membrane rolled into a cylindrical shape. The electrode assembly is disposed within the container and functions as an electrical energy storage element. The current collector may comprise copper or aluminum foil coated with an active material, and the porous membrane may be polymeric or ceramic. An electrolyte fills the remaining volume of the container and permeates the active material on the current collector and separator. A cap, which serves as the positive electrode, is crimped into place on top of the can to complete the cell and enclose the electrode assembly within the container. Several important questions remain regarding the operation of lithium-ion battery packs. [Brief explanation of the drawings]

[0004] [Figure 1]

[0004] Figure 1 illustrates a battery assembly having a plurality of battery cells within a housing, the battery assembly further including, according to an embodiment of the present disclosure, (i) an outgassing sensor within the housing, the outgassing sensor configured to sense an outgassing event of one or more battery cells and output a first sensing signal; (ii) a pressure relief device within the housing, the pressure relief device configured to release gas pressure from the housing in response to the pressure within the housing exceeding a threshold; (iii) a pressure relief sensor configured to sense a pressure relief event caused by the pressure relief device and output a second sensing signal; and (iv) a processor within the housing configured to receive the first sensing signal and the second sensing signal and transmit information related to the first and second sensing signals to a system external to the housing. [Figure 2A]

[0005] FIG. 2A illustrates a plot depicting a sensing signal output by an outgassing sensor of the battery assembly of FIG. 1 according to an embodiment of the present disclosure. [Figure 2B]

[0006] FIG. 2B illustrates a plot depicting a sensing signal output by a pressure release sensor of the battery assembly of FIG. 1 according to an embodiment of the present disclosure. [Figure 3]

[0007] FIG. 3 illustrates details of communication between the processor of the battery assembly of FIG. 1 and a system external to the housing, according to an embodiment of the present disclosure. [Figure 4A]

[0008] FIG. 4A illustrates the battery assembly of FIG. 1 along with operation of a switch within the battery assembly housing, the switch operable to disconnect the plurality of battery cells from a load external to the housing in response to detection of an outgassing event and / or a pressure relief event, in accordance with an embodiment of the present disclosure. [Figure 4B] FIG. 4B illustrates the battery assembly of FIG. 1 with operation of a switch within the battery assembly housing, the switch operable to disconnect the plurality of battery cells from a load external to the housing in response to detection of an outgassing event and / or a pressure relief event, in accordance with an embodiment of the present disclosure. [Figure 5A]

[0009] FIG. 5A illustrates a flowchart depicting a method for operating the battery assembly of FIGS. 1, 3, 4A, and 4B according to an embodiment of the present disclosure, wherein switches for connecting and disconnecting the plurality of battery cells to a load are controlled by a processor located within the housing. [Figure 5B]

[0010] FIG. 5B illustrates a flowchart depicting a method for operating the battery assembly of FIGS. 1, 3, 4A, and 4B according to an embodiment of the present disclosure, wherein switches for connecting and disconnecting the plurality of battery cells to a load are controlled by a system external to the housing.

[0005]

[0011] The figures depict various embodiments of the present disclosure for purposes of illustration only and are not necessarily drawn to scale. Numerous variations, configurations and other embodiments will become apparent from the following detailed description. DETAILED DESCRIPTION OF THE INVENTION

[0006]

[0012] Methods and structures for mitigating the propagation of thermal runaway in a battery assembly, such as a lithium-ion battery assembly, are disclosed. According to some exemplary embodiments, the battery assembly includes a housing and a plurality of battery cells within the housing. A pressure relief device (such as a burst disk device) is within the housing, and the pressure relief device is configured to release gas pressure from the housing (e.g., by rupturing a diaphragm of the burst disk) in response to gas pressure exceeding a threshold value due to outgassing of one or more battery cells within the housing during a fault condition of one or more battery cells. A pressure relief sensor within the housing is configured to output a pressure relief sensing signal indicative of such a pressure relief event. The outgassing sensor within the housing is configured to sense any outgassing within the housing due, for example, to a fault condition of one or more battery cells, and the outgassing sensor is configured to output an outgassing sensing signal indicative of any outgassing event.

[0007]

[0013] In some embodiments, a processor within the housing is configured to receive the pressure release sensing signal and the outgassing sensing signal. In some such embodiments, the processor may forward the pressure release sensing signal and the outgassing sensing signal to a control system external to the housing, where the forwarded pressure release sensing signal and the outgassing sensing signal may be, for example, analog discrete signals. In some such embodiments, the processor may also send information associated with the pressure release sensing signal and the outgassing sensing signal to the control system, where the information is forwarded as a digital signal including an indication of the outgassing event and / or the pressure release event, and may also include other relevant information, such as a timestamp of such event, a measurement of the gas pressure, and / or the concentration of the gas detected by the outgassing sensor.

[0008]

[0014] In some examples, the housing also includes a switch for selectively coupling the plurality of battery cells to a load external to the housing. The switch may be controlled by a system external to the housing and / or by a processor within the housing. In some such examples, during normal operation of the battery assembly (e.g., when no outgassing or pressure relief event is detected), the switch is in a closed state, coupling the battery cells to the load. However, in response to detection of an outgassing or pressure relief event, the switch transitions to an open state, disconnecting the battery cells from the load. Thus, upon detection of an outgassing or pressure relief event, the battery is not loaded, thereby reducing the possibility of thermal runaway and, as a result, reducing the risk of fire. Numerous variations and embodiments will become apparent in light of this disclosure.

[0009] General Overview

[0015] As discussed above, several significant issues remain regarding the operation of lithium-ion battery packs. One challenge with lithium-ion battery technology is thermal management. The potential for thermal runaway during the use, handling, and / or transportation of lithium-ion batteries is a current concern. Thermal runaway occurs when a series of self-sustaining exothermic side reactions leads to complete cell failure and, potentially, fire and / or explosion. A battery cell experiencing thermal runaway can emit hot gases, flames, and high-velocity jets of molten particulate matter called ejecta. Lithium-ion batteries have the potential to experience thermal runaway due to the chemistry of lithium-ion technology. While significant progress has been made over time to improve cell performance (e.g., reducing capacity fade, increasing available power, etc.), challenges with thermal runaway and its propagation remain. For example, the materials and structure of individual battery cells or battery packs can result in localized hot spots or heating that can lead to cell failure. Additionally, over-constraining battery cells can result in large pressure gradients that can lead to failure of mechanical components such as plates and fasteners around the battery cell. Similarly, the failure to vent the ejection can lead to the momentary formation of localized hot spots that can trigger thermal runaway in nearby battery cells. Therefore, there is a need for structures and methods to mitigate the propagation of thermal runaway in lithium-ion battery packs.

[0010]

[0016] Accordingly, techniques are described herein for forming battery assemblies in which battery failure is detected at an early stage and mitigating action is taken in response to such detection, thereby preventing or at least reducing the chance of thermal runaway and any resulting fire hazard in the battery assembly.

[0011]

[0017] In some embodiments, the battery assembly includes a substantially airtight housing and a plurality of battery cells within the housing. In some examples, the battery cells may be lithium-ion battery cells, although other types of battery cells (such as lead-acid or hydrogen cells) may also benefit from the techniques described herein.

[0012]

[0018] During fault operation of a battery cell, gas may be released by the battery cell (referred to herein as "outgassing" of the battery cell); examples of such released gas are described herein below. Such released gas can increase gas pressure within the battery housing, potentially contributing to thermal runaway and fire hazards, and potentially causing structural damage to the housing. In one embodiment, a pressure relief device is mounted within the housing. In one example, the pressure relief device is a burst disk device, although other types of pressure relief devices could alternatively be used. The pressure relief device is configured to release gas pressure from the housing, for example, by rupturing a diaphragm of a burst disk, in response to gas pressure exceeding a threshold value due to outgassing of one or more battery cells during a fault condition.

[0013]

[0019] In some embodiments, the pressure relief sensor in the housing is configured to output a pressure relief sense signal indicative of such a pressure relief event. For example, the pressure relief sense signal may change from a first voltage level to a second voltage level in response to the pressure relief device releasing gas (e.g., by rupturing a diaphragm of a burst disk or by another suitable method).

[0014]

[0020] In some embodiments, an outgassing sensor in the housing is configured to sense any outgassing in the housing, for example, due to a fault condition in one or more battery cells. The outgassing sensor is configured to output an outgassing sensing signal, which can change from one voltage level to another voltage level in response to the outgassing sensor detecting at least a threshold amount of outgassing in the housing. The outgassing detected by the outgassing sensor can include gases released by the battery cells during malfunction of the battery cells, examples of which are described herein below.

[0015]

[0021] In some embodiments, a processor within the housing is configured to receive the pressure release sensing signal and the outgassing sensing signal. In some such embodiments, the processor may forward the pressure release sensing signal and the outgassing sensing signal to a control system external to the housing, where the forwarded pressure release sensing signal and the outgassing sensing signal may be, for example, an analog discrete signal. In some such embodiments, the processor may also send information related to the pressure release sensing signal and the outgassing sensing signal to the control system, where the information is forwarded as a digital signal including an indication of the outgassing event and / or the pressure release event and may also include other relevant information, such as a timestamp of such event, a measurement of the gas pressure, and / or the concentration of the gas detected by the outgassing sensor. The processor may transmit the information related to the pressure release sensing signal and the outgassing sensing signal to the external system via a first communication link, such as a controller area network (CAN) bus. The processor may also transmit the discrete pressure release sensing signal and the outgassing sensing signal via a second communication link different from the first communication link.

[0016]

[0022] In some examples, the housing also includes a switch for selectively coupling the plurality of battery cells to a load external to the housing. In some examples, the switch may be a contactor. The switch may be controlled by a system external to the housing and / or by a processor within the housing. For example, the system and / or processor may generate one or more control signals to control operation of the switch.

[0017]

[0023] During normal operation of the battery assembly (eg, when no outgassing or pressure relief event is detected), the switch is in a closed state, coupling the battery cell to the load.

[0018]

[0024] However, in response to detecting an outgassing event or a pressure relief event, the switch transitions to an open state, disconnecting the battery cell from the load. For example, in response to detecting an outgassing event or a pressure relief event, a control signal generated by the system and / or processor instructs the switch to transition to an open state. Thus, upon detection of an outgassing event or a pressure relief event, the battery is unloaded (by the switch transitioning to the open state), thereby reducing the possibility of thermal runaway and, as a result, reducing the risk of fire.

[0019]

[0025] According to some embodiments of the present disclosure, these various approaches can be used individually or together to reduce or eliminate thermal runaway propagation within a battery pack assembly. Numerous variations and embodiments will become apparent in light of the present disclosure.

[0020]

[0026] As used in the discussion and claims herein, the term "about" indicates that the recited value may be varied somewhat as long as the variation does not result in process or device incompatibility. For example, for some elements, the term "about" may refer to a variation of +-0.1%, while for other elements, the term "about" may refer to a variation of +-1% or +-10%, or any point therein. Also, as used herein, terms defined in the singular are intended to include terms defined in the plural, and vice versa.

[0021]

[0027] Reference herein to any range of values ​​expressly includes each value (including fractions and integers) subsumed within that range. By way of example, reference herein to a range of "at least 50" or "at least about 50" includes integers such as 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, etc., and fractions such as 50.1, 50.2, 50.3, 50.4, 50.5, 50.6, 50.7, 50.8, 50.9, etc. In further illustration, references herein to ranges of "less than 50" or "less than about 50" include integers such as 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, etc., and fractions such as 49.9, 49.8, 49.7, 49.6, 49.5, 49.4, 49.3, 49.2, 49.1, 49.0, etc.

[0022]

[0028] As used herein, the terms "substantially" or "substantial" are equally applicable when used in the negative sense to refer to the complete or nearly complete absence of an action, characteristic, property, state, structure, item, or result. For example, a surface that is "substantially" flat is either completely flat or so nearly flat that the effect is the same as if it were completely flat.

[0023] architecture

[0029] FIG. 1 illustrates a battery assembly 100 having a plurality of battery cells 102a, ..., 102n within a housing 101, the battery assembly 100 further including, according to an embodiment of the present disclosure, (i) an outgassing sensor 116 within the housing 101, the outgassing sensor 116 configured to sense an outgassing event of one or more of the battery cells 102 and output a first sensing signal 117; (ii) a pressure relief device 108 within the housing 101, the pressure relief device 108 configured to release gas pressure from the housing 101 in response to the pressure within the housing 101 exceeding a threshold; (iii) a pressure relief sensor 112 configured to sense a pressure relief event caused by the pressure relief device 108 and output a second sensing signal 113; and (iv) a processor configured to receive the first sensing signal 117 and the second sensing signal 113 and transmit information related to the first and second sensing signals 113, 117 to a system 180 external to the housing 101.

[0024]

[0030] In one example, the housing 101 is substantially airtight. In one example, the housing 101 is completely airtight or sealed. In another example, the housing 101 may be substantially sealed and have slight gas leaks through the housing 101. However, even if there is a slight gas leak through the housing 101, such gas leaks may not be significant and may not relieve or vent high gas pressures generated within the housing 101 due to the failure of one or more battery cells 102. In one example, such gas pressures may instead be vented through a pressure relief device 108, as described in more detail herein. In some examples, the walls of the housing 101 comprise a metal, and in some other examples, the walls of the housing 101 comprise a non-metal. In one example, the walls of the housing 101 comprise a combination of a metal and a non-metal.

[0025]

[0031] In one embodiment, the individual battery cells 102 may comprise any suitable type of battery cell. For example, the individual battery cells 102 may comprise lithium-ion battery cells, although the battery cells 102 may also be of another suitable type, such as lead-acid battery cells or hydrogen cells. In one example, the multiple battery cells 102 a, ..., 102 n may be coupled in a series and / or parallel connection. In one example, the battery cells 102 a, ..., 102 n may be of any suitable size and may have any suitable shape or form factor. In one embodiment, each battery cell 102 includes an electrolyte in a corresponding container, although the electrolyte and containers of the battery cells 102 are not shown in FIG. 1 .

[0026]

[0032] In one example, a battery cell 102 may fail due to, for example, overcharging, overheating, over-discharging, or another suitable reason. In one example, battery cell outgassing (sometimes referred to as off-gassing) may occur during the early stages of battery failure. When battery cell outgassing occurs, if no action is taken to remedy the cause of the failure, the battery cell may progress to thermal runaway and even explode, resulting in a fire. In an example, outgassing may result from, for example, vaporization of the battery cell electrolyte and / or other gases generated within the battery cell due to a fault condition within the battery cell. In such an example, such vapors and / or gases may be released from the battery cell. Examples of gases released from lithium-ion battery cells include hydrogen, methane, ethane, methylene, propylene, carbon monoxide, carbon dioxide, and / or organic carbonates, and the gases released from the battery cell may depend on the electrolyte and / or other materials used within the battery cell.

[0027]

[0033] In one embodiment, the outgassing sensor 116 is configured to detect an outgassing event in one or more of the plurality of battery cells 102 a, ..., 102 n. For example, the outgassing sensor 116 is mounted proximate to the battery cell 103, and the outgassing sensor 116 monitors the gas space inside the housing 101. The gases monitored by the outgassing sensor 116 can be based on the type of battery cell 102 used in the assembly 100. For example, if the battery cell 102 comprises a lithium-ion battery cell, the outgassing sensor 116 can monitor lithium-ion battery electrolyte vapor and / or other gases potentially produced by the battery cell during a fault condition. The outgassing sensor 116 can detect gases from the battery cell 103, for example, at a detection threshold at the parts per million (ppm) level.

[0028]

[0034] In one embodiment, the outgassing sensor 116 outputs a sensing signal 117. When the outgassing sensor 116 detects a gas leak from one or more battery cells 102 (e.g., detects an outgassing event), the sensing signal 117 indicates such detection. For example, upon detecting an outgassing event, the sensing signal 117 changes from a first signal level to a second signal level. FIG. 2A illustrates a plot depicting the sensing signal 117 output by the outgassing sensor 116 of the battery assembly 100 of FIG. 1 according to one embodiment of the present disclosure. The X-axis of the plot in FIG. 2A represents time, and the Y-axis of the plot represents the sensing signal 117. For example, when no outgassing event is detected, the outgassing sensor 116 may output the sensing signal 117 at a first voltage V1 (e.g., 0.50 V DC (direct current)). Upon detecting an outgassing event, the outgassing sensor 116 may output the sensing signal 117 at a second voltage level V2 (e.g., 3.0 V DC). Thus, the sensing signal 117 provides an indication of an outgassing event.

[0029]

[0035] In one embodiment, during an outgassing event, gas pressure within the enclosure 101 increases due to, for example, evaporation of electrolyte in one or more of the battery cells 102a, ..., 102n due to a fault condition in one or more of the battery cells. In one example, the outgassing sensor 116 detects such an outgassing event and indicates such detection via the sensing signal 117 (e.g., by increasing the sensing signal 117 from voltage V1 to voltage V2, see FIG. 2A ). As described in further detail herein, preventative action can be taken (e.g., by the processor 104 and / or the system 180) to remedy the conditions causing the outgassing event (e.g., by shutting down the battery cells 102a, ..., 102n). However, in one example, the outgassing detection and / or such corrective action may not be sufficient or timely, and the gas pressure within the enclosure 101 may increase. Such an increase in gas pressure may cause thermal runaway, a fire hazard, and / or structural damage to the enclosure 101.

[0030]

[0036] Thus, in one embodiment, the pressure relief device 108 within the housing 101 releases gas pressure from the housing 101, for example, in response to gas pressure within the housing 101 exceeding a threshold value. In one example, the pressure relief device 108 is a burst or rupture disk attached to a wall of the housing 101. The burst or rupture disk is a pressure relief safety device that protects the system 100 from over-pressurization and the resulting fire hazard and / or structural damage. For example, the pressure relief device 108 has a non-reclosing sacrificial portion that is a disposable membrane or diaphragm. The diaphragm breaks or ruptures above a predetermined pressure differential between the interior of the housing 101 and the ambient. For example, when the gas pressure within the housing 101 exceeds a threshold pressure, the diaphragm breaks or ruptures (referred to herein as a pressure relief event), thereby rapidly releasing gas from within the housing 101 and thereby relieving or reducing the gas pressure within the housing 101. For example, when pressure relief device 108 is actuated or ruptured, it reduces the pressure within housing 101 in a relatively short period of time (e.g., a few seconds or milliseconds or microseconds). In one example, if the diaphragm ruptures, it may not reseal and pressure relief device 108 may become inoperable until the diaphragm is repaired or replaced.

[0031]

[0037] In one embodiment, pressure relief sensor 112 senses a pressure relief event caused by pressure relief device 108. For example, pressure relief sensor 112 outputs a sensing signal 113 indicative of a pressure relief event. In one example, pressure relief sensor 112 may be integrated with pressure relief device 108. For example, rupture of a diaphragm of pressure relief device 108 may be detected by pressure relief sensor 112.

[0032]

[0038] 2B illustrates a plot depicting the sensing signal 113 output by the pressure relief sensor 112 of the battery assembly 100 of FIG. 1 , according to one embodiment of the present disclosure. The X-axis of the plot represents time, and the Y-axis of the plot represents the sensing signal 113. For example, when no pressure relief event is detected, the pressure relief sensor 112 may output the sensing signal 113 at a first voltage Va (e.g., 0.50 V DC). Upon detecting a pressure relief event, the pressure relief sensor 112 may output the sensing signal 113 at a second voltage level Vb (e.g., 3.0 V DC). Thus, the sensing signal 113 provides an indication of the pressure relief event.

[0033]

[0039] In one embodiment, the sense signals 113 and 117 may be received by a processor 104, also located within the housing 101. In an example, the processor 104 is a microcontroller. While not shown, in one example, the processor 104 is coupled to a communications chip, for example, to communicate with the sensors 116, 112 and / or to communicate with the system 180. In one embodiment, the processor 104 is coupled to a computer-readable storage medium 105, such as a memory 105 or a data storage device 105, also located within the housing 101. In one embodiment, the computer-readable storage medium 105 stores instructions or code that, when executed by the processor 104, cause the processor 104 to perform operations to protect the battery assembly 100 from various hazards, as described herein.

[0034]

[0040] In one embodiment, the processor 104 and / or memory 105 are on a printed circuit board (PCB), and the PCB is mounted within the housing 101. In one example, the PCB is mounted to a wall of the housing 101 that is as far away as possible from another wall on which the pressure relief device 108 is located (e.g., to prevent the processor 104 and / or memory 105 from being damaged during a pressure relief event). For example, as shown in FIG. 1 , the housing 101 has a first wall and an opposing second wall, and the PCB including the processor 104 and / or memory 105 is mounted to the first wall and the pressure relief device 108 is mounted to the second wall.

[0035]

[0041] In one embodiment, the processor 104 receives the sensed signals 113 , 117 and transmits the sensed signals 113 , 117 and / or information associated therewith to a system 180 external to the housing 101 via a communication link 184 .

[0036]

[0042] 3 illustrates further details of communication between the processor 104 of the battery assembly 100 and a system 180 external to the housing 101, according to one embodiment of the present disclosure. In the example of FIG. 3, the processor 104 transmits the sensing signals 113, 117 over a first communication link 184a. For example, the processor 104 does not modify or process the sensing signals 113, 117 but simply retransmits or forwards the sensing signals 113, 117 received from the sensors 112, 116, respectively, to the system 180 over the communication link 184a. In one example, the retransmission of the sensing signals 113, 117 may be performed by the processor 104 or by a dedicated hardware circuit (not shown) coupled to the processor 104 that receives and retransmits the sensing signals 113, 117. In one example, the sensing signals 113, 117 transmitted over the communication link 184a comprise discrete signals (e.g., having two states, such as an on state and an off state, or a "0" state and a "1" state, or V1 and V2, or Va and Vb, see FIGS. 2A, 2B). In one example, the sensing signals 113, 117 transmitted over the communication link 184a comprise analog signals.

[0037]

[0043] In one example, the processor 104 can also transmit information 204, 208 associated with the sensing signals 113, 117, respectively, to the system 180, for example, via communication link 184b, as shown in FIG. 3. In one example, the communication link 184b is a controller area network (CAN) bus. For example, the processor 104 processes the sensing signals 113, 117 and generates information 204, 208, respectively. The processor transmits the information 204, 208 to the system 180 via communication link 184b. For example, the information 204, 208 can include bits of data indicative of an outgassing event and / or a pressure release event, if such an event occurs.

[0038]

[0044] In one example, the information 204, 208 may further include any other suitable information. For example, the information 204, 208 may include a timestamp of the associated event. In another example, if the sensing signal 117 provides a concentration level (e.g., in ppm) and / or type of gas detected by the outgas sensor 116, the information 204 may include such information.

[0039]

[0045] Thus, in one example, the sensed signals 113, 117 transmitted over the communication link may be analog and / or discrete signals generated by the sensors 112, 116, respectively, and retransmitted by the processor 104. In contrast, the information 204, 208 associated with the sensed signals 113, 117, respectively, may be digital data generated by the processor 104 based on the sensed signals 113, 117.

[0040]

[0046] 4A and 4B illustrate the battery assembly 100 of FIG. 1 along with the operation of a switch 304 within the housing 101 of the battery assembly 100, the switch 304 operable to disconnect the plurality of battery cells 102a, ..., 102n from a load 350 external to the housing 101 in response to detecting an outgassing event and / or a pressure relief event, in accordance with one embodiment of the present disclosure.

[0041]

[0047] 4A and 4B, the switch 304 couples the battery cells 102a, ..., 102n to an external load 350 that is external to the housing 101. In one example, the switch 304 is a contactor, e.g., a device for opening and closing an electrical circuit. The load 350 may be any suitable type of load that receives DC power from the battery cells 102a, ..., 102n.

[0042]

[0048] 4A and 4B, the battery cells 102a, ..., 102n are shown in series with the load 350, but this need not be the case. For example, a first battery cell may be in parallel with a second battery cell, and the parallel combination may be in series with a third battery cell. Any other suitable series / parallel combination of the battery cells 102a, ..., 102n may also be possible.

[0043]

[0049] The connection between the battery cells 102a, ..., 102n and the load 350 is via the switch 304. Thus, when the switch 304 is closed (as in FIG. 4A ), the load 350 is coupled to the battery cells 102a, ..., 102n. When the switch 304 is open (as in FIG. 4B ), the load 350 is disconnected from the battery cells 102a, ..., 102n. Thus, FIG. 4A illustrates a closed state of the switch 304 when no outgassing event and / or pressure relief event is detected, such as during normal operation of the battery assembly 100. FIG. 4B illustrates an open state of the switch 304 when, for example, an outgassing event and / or pressure relief event is detected.

[0044]

[0050] In one embodiment, the switch 304 is controlled by one or more of the control signals 308, 312, 316. While Figure 4A illustrates three control signals 308, 312, 316, the battery assembly 100 may have any single control signal, any two control signals, or all three control signals 308, 312, 316 based on the implementation of the battery assembly 100.

[0045]

[0051] In one example, the control signal 308 is generated by the system 180 and transmitted to the switch 304, for example, bypassing the processor 104. Thus, the control signal 308 may be transmitted from the system 180 to the enclosure 101 and the switch 304 using a communication link different from the communication links 184, 184a, 184b described with respect to Figures 1 and 3.

[0046]

[0052] 1 and 3, system 180 may receive sensing signals 113, 117 and / or may receive (e.g., via communication link 184) information 204, 208 related to sensing signals 113, 117, respectively. During normal operation of battery assembly 100 (e.g., when no outgassing or pressure relief event is detected), control signal 308 may indicate a closed state for switch 304, as seen in FIG. 4A, such that load 350 receives power from battery cells 102a, ..., 102n via switch 304.

[0047]

[0053] In one embodiment, in response to the sensing signals 113, 117 and / or the information 204, 208 indicative of the outgassing event and / or pressure relief event, the system 180 may change the state of the control signal 308, for example, to indicate the switch 304 to switch from a closed state to an open state, as seen in FIG. 4B . In the open state of operation of the switch 304, the load 350 is disconnected from the battery cells 102 a, ..., 102 n by the switch 304. Because the battery cells 102 a, ..., 102 n are now disconnected from the load 350, the battery cells 102 a, ..., 102 n are now unloaded, which eliminates or reduces the possibility of thermal runaway and fire hazards from the reasons that caused the detected outgassing event and / or pressure relief event.

[0048]

[0054] In one example, the control signal 312 is generated by the system 180 and transmitted to the switch 304 via the processor 104. Thus, the control signal 308 is transmitted by the system 180 directly to the switch 304 (e.g., by bypassing the processor 104), while the control signal 312 is transmitted by the system 180 to the switch 304 via the processor 104. For example, the control signal 312 is transmitted by the system 180 to the processor 104 via the communication link 184 described with respect to FIG. 1 , and the processor 104 then transmits the control signal 312 to the switch 304. In one example, the system 180 transmits either the control signal 308 or the control signal 312 to the switch 304.

[0049]

[0055] In one example, the control signal 316 is generated by the processor 104 and transmitted to the switch 304, for example, based on the processor 104 receiving and analyzing the sensed signals 113, 117. The operation of the control signal 316 may be at least partially similar to the operation of the control signal 308 described above.

[0050]

[0056] Thus, either the processor 104 or the system 180, or both, can control the switch 304, for example, using one or more of the control signals 308, 312, or 316. In one embodiment, as described above, the system 180 can automatically control the switch 304 via the control signals 308 and / or 312. In another example, the user 301 may interact with the system 180, for example, to be notified of the sensed signals 113, 117 and / or the associated information 204, 208. In one embodiment, there may be a manual override that can be used by the user 301 to override the automatic control of the switch 304, and the user 301 may manually control the switch 304, for example, through the system 180.

[0051]

[0057] In one example, the battery assembly 100 may be installed in a vehicle such as a hybrid electric vehicle (HEV) or battery electric vehicle (BEV), including a personal vehicle such as a scooter, car, motorcycle, or truck, or a commercial vehicle such as a truck or bus, a marine vehicle such as a boat, an unmanned underwater vehicle (UUV) or submarine, or a military vehicle such as a tank, self-propelled artillery, or troop carrier. In one example, the battery assembly 100 may be installed in an aircraft such as an airplane or helicopter, an unmanned aerial vehicle (UAV), a missile system, a spacecraft, or another powered air vehicle.

[0052]

[0058] For example, if the battery assembly 100 is installed in a vehicle (such as an aircraft), the battery assembly 100 must comply with various strict standards applicable to such sensitive installations. Such installations of the battery assembly 100 may require a low probability of thermal runaway of the battery assembly 100 and a low probability of a resulting fire hazard. In one embodiment, the use of the outgassing sensor 116, as well as the pressure relief device 108 and the pressure relief sensor 112, may ensure that an outgassing event and / or a pressure relief event is detected in a timely manner, for example, prior to the occurrence of thermal runaway. The sensing signals 113, 117 may be used to deliver a warning well in advance of thermal runaway and take automatic action, such as opening the switch 304, thereby preventing or reducing the probability of a thermal runaway event and the resulting potential fire hazard in the battery assembly 100.

[0053]

[0059] 5A illustrates a flowchart depicting a method 500 for operating the battery assembly 100 of FIGS. 1, 3, 4A, and 4B according to one embodiment of the present disclosure, wherein a switch 304 for connecting and disconnecting the plurality of battery cells 102 a, ..., 102 n to a load 350 is controlled by a processor 104 within the housing 101. At 504 of the method 500, power is supplied from the plurality of battery cells 102 a, ..., 102 n within the housing 101 to the load 350 outside the housing 101 via the switch 304, as illustrated in FIG. 4A , for example. For example, in FIG. 4A , the switch 304 is in a closed state, thereby supplying power from the plurality of battery cells 102 a, ..., 102 n to the load 350.

[0054]

[0060] Method 500 continues from 504 to 508 and 512. At 508, an outgassing sensor 116 within the housing 101 outputs a sensing signal 117 in response to monitoring a concentration of one or more gases released from one or more of the battery cells 102a, ..., 102n. For example, the one or more gases include electrolyte vapor within the battery cell and / or other gases produced by the battery cell during a fault condition that may be released from the battery cell during a fault condition within the battery cell. If the gas concentration exceeds a threshold level, the outgassing sensor 116 detects an outgassing event and provides an indication of the outgassing event via the sensing signal 117, for example, as described with respect to FIG. 2A .

[0055]

[0061] At 512, a pressure relief sensor 112 within the housing 101 outputs a sensing signal 113 in response to monitoring the operation of a pressure relief device 108 within the housing 101. For example, if the gas pressure within the housing 101 exceeds a threshold, the pressure relief device 108 (e.g., a burst disk in one example) releases gas, for example, by rupturing a diaphragm or disk of the burst disk device. In response to such a pressure relief event, the pressure relief sensor 112 provides an indication of the pressure relief event via the sensing signal 113, for example, as described with respect to FIG. 2B .

[0056]

[0062] Method 500 proceeds from 508 and 512 to 516, where processor 104, also within housing 101, (i) transmits information related to sensing signals 113, 117 to system 180 external to housing 101 via communication link 184b, and (ii) transmits sensing signals 113, 117 to system 180 via communication link 184a, for example, as described in further detail with respect to FIG. 3.

[0057]

[0063] Method 500 proceeds from 516 to 520, where processor 104 and / or system 180 detects whether an outgassing event and / or pressure relief event has occurred, for example, based on sensing signals 113, 117 and / or information associated with sensing signals 113, 117. If "No" at 520 (e.g., an outgassing event and / or pressure relief event has not been detected), method 500 loops back at 520, where processor 104 and / or system 180 continues to perform detection. It should be noted that operations at 504, 508, 512, 516, and 520 occur continuously during normal or standard operation of battery assembly 100, for example, until a positive detection is made at process 520.

[0058]

[0064] If 520 returns "yes" (e.g., an outgassing event and / or a pressure relief event is detected), method 500 proceeds from 520 to 524. At 524, processor 104 issues a command (e.g., using control signal 316) to transition switch 304 from its current closed state to an open state. For example, control signal 316 transitions from one voltage level to another voltage level, indicating switch 304 should transition to the open state.

[0059]

[0065] The method 500 proceeds from 524 to 528, where the switch 304 transitions to an open state, disconnecting the plurality of battery cells 102 a, ..., 102 n from the load 350, based on a command received via the control signal 316 from the processor 104 (see process 524 of method 500), for example, as also described herein above with respect to FIG. 4B.

[0060]

[0066] Thus, disconnecting the load 350 from the battery cells 102a, ..., 102n in response to detecting an outgassing event and / or a pressure relief event prevents or reduces the chance of thermal runaway in one or more battery cells, thereby preventing or reducing the chance of a fire hazard in the battery assembly 100.

[0061]

[0067] FIG. 5B illustrates a flowchart depicting a method 500b for operating the battery assembly 100 of FIGS. 1, 3, 4A, and 4B, according to one embodiment of the present disclosure, wherein the switch 304 for connecting and disconnecting the plurality of battery cells 102a, ..., 102n to the load 304 is controlled by a system 180 external to the housing 101.

[0062]

[0068] Various processes of method 500b of Figure 5B are similar to corresponding processes in method 500 of Figure 5A, and similar processes in both methods are labeled using the same labels. However, process 524 in method 500 of Figure 5A was performed by processor 104 within housing 101. In contrast, in method 500b of Figure 5B, corresponding process 524b may be performed by system 180 external to housing 101.

[0063]

[0069] For example, after an outgassing event and / or a pressure relief event is detected at 520, method 500b of Figure 5B proceeds to 524b. At 524b, system 180 issues a command (e.g., using control signal 308 or 312, see Figure 3) to transition switch 304 from its currently closed state to an open state. For example, control signal 308 or 312 transitions from one voltage level to another, indicating switch 304 to transition to the open state. From 524b, method 500b proceeds to 528, as described with respect to Figure 5A.

[0064]

[0070] Thus, in one example, the processor 104 or the system 180 can automatically control the switch 304 via the control signals 308, 312, or 316, as described above with respect to 524 of Figure 5A and 524b of Figure 5B. In another example, both the processor 104 and the system 180 can each issue a command to the switch 304 to transition to an open state, which is, for example, a combination of processes 524 and 524b of Figures 5A and 5B.

[0065]

[0071] In yet another example, in addition to or instead of processor 104 and / or system 180 automatically controlling switch 304, user 301 (see FIG. 3 ) may manually control switch 304. For example, user 301 may interact with system 180 and / or processor 104, for example, to be notified of sensed signals 113, 117 and / or associated information 204, 208. In one embodiment, there may be a manual override that can be used by user 301 to override the automatic control of switch 304 by processor 104 and / or system 180, and user 301 may manually control switch 304, for example, through system 180 and / or processor 104.

[0066] Further Exemplary Embodiments

[0072] The following examples relate to further embodiments, from which numerous permutations and configurations will become apparent.

[0067]

[0073] Example 1: A battery assembly comprising: a housing; an outgassing sensor within the housing, the outgassing sensor configured to sense an outgassing event of one or more battery cells within the housing and output a first sensing signal; a pressure relief device within the housing, the pressure relief device configured to release gas pressure from the housing in response to pressure within the housing exceeding a threshold; a pressure relief sensor within the housing, the pressure relief sensor configured to sense a pressure relief event caused by the pressure relief device and output a second sensing signal; and a processor within the housing, the processor configured to receive the first sensing signal and the second sensing signal and to transmit information related to the first and second sensing signals to a system external to the housing.

[0068]

[0074] Example 2: The battery assembly of Example 1, wherein the pressure release device is a burst disk, and wherein the pressure release event is a burst disk event in which a disk of the burst disk ruptures, and wherein the pressure release sensor is a burst disk sensor configured to provide an indication of the burst disk event within the second sense signal.

[0069]

[0075] Example 3: The battery assembly of Example 1 or 2, further comprising: a plurality of battery cells within the housing including the one or more battery cells; and a switch within the housing, wherein the plurality of battery cells are coupled to a circuit external to the housing via the switch, and wherein the switch is configured to disconnect the plurality of battery cells from the circuit external to the housing in response to receiving a control signal generated in response to the first sensing signal indicative of the outgassing event and / or the second sensing signal indicative of the pressure release event.

[0070]

[0076] Example 4. The battery assembly of example 3, wherein the control signal is generated by the processor.

[0071]

[0077] Example 5. The battery assembly of Example 3, wherein the control signal is generated by the system external to the housing and transmitted to the switch via the processor.

[0072]

[0078] Example 6. The battery assembly of Example 3, wherein the control signal is generated by the system external to the housing and transmitted to the switch, bypassing the processor.

[0073]

[0079] Example 7. The battery assembly of any one of Examples 1 to 6, wherein the processor is further configured to forward the first and second sensing signals to the external system in addition to transmitting information associated with the first and second sensing signals to the external system.

[0074]

[0080] Example 8. The battery assembly of Example 7, wherein the first and second sensing signals forwarded by the processor to the external system are analog discrete signals, and the information related to the first and second sensing signals transmitted by the processor to the external system comprises a digital signal.

[0075]

[0081] Example 9. The battery assembly of any one of Examples 1 to 8, wherein the information associated with the first sensing signal comprises an indication of the outgassing event and the information associated with the second sensing signal comprises an indication of the pressure release event.

[0076]

[0082] Example 10. The battery assembly of any one of Examples 1 to 9, wherein the information associated with the first sensing signal comprises a sensed concentration of the outgassing and a timestamp of the outgassing event.

[0077]

[0083] Example 11. The battery assembly of any one of Examples 1 to 10, wherein the outgassing sensor senses the outgassing event in response to detecting at least a threshold level of one or more gases emitted by the one or more battery cells.

[0078]

[0084] Example 12. The battery assembly of Example 11, wherein the one or more gases include vapor of a lithium ion battery electrolyte solvent.

[0079]

[0085] Example 13. The battery assembly of any one of Examples 1 to 12, wherein the one or more battery cells include one or more lithium ion battery cells.

[0080]

[0086] Example 14. The battery assembly of any one of Examples 1 to 13, wherein the housing has a first wall and an opposing second wall, the processor is on a printed circuit board (PCB) attached to the first wall, and the pressure relief device is attached to the second wall such that, during the pressure release event, pressure is released through an opening in the pressure relief device.

[0081]

[0087] Example 15. A method of operating a battery assembly, the method comprising: outputting, by an outgassing sensor within a housing, a first sensing signal in response to monitoring a concentration of one or more gases from one or more battery cells within the housing; outputting, by a pressure relief sensor within the housing, a second sensing signal in response to monitoring operation of a pressure relief device within the housing; and transmitting, by a processor within the housing, information related to the first and second sensing signals to a system external to the housing.

[0082]

[0088] Example 16. The method of Example 15, further comprising: connecting a plurality of battery cells to a load external to the housing via a switch located within the housing, the plurality of battery cells being within the housing and including the one or more battery cells; and disconnecting the plurality of battery cells from the load by the switch in response to receiving a control signal generated in response to the first sensing signal indicative of an outgassing event and / or the second sensing signal indicative of a pressure release event.

[0083]

[0089] Example 17. The method of Example 16, further comprising generating the control signal based on monitoring, by the system external to the housing and / or by the processor system within the housing, the first and second signals and / or the information related to the first and second sensed signals.

[0084]

[0090] Example 18: A battery assembly comprising: a housing; a plurality of battery cells within the housing; one or more sensors configured to monitor one or more events associated with the plurality of battery cells; and a processor within the housing, wherein the processor is configured to (i) receive the one or more sensed signals from the one or more sensors; (ii) transmit information associated with the one or more sensed signals to a system external to the housing via a first communication link; and (iii) forward the one or more sensed signals to the system external to the housing via a second communication link different from the first communication link.

[0085]

[0091] Example 19: The battery assembly of Example 18, wherein the one or more sensors comprise: (i) an outgassing sensor configured to sense an outgassing event of one or more battery cells among the plurality of battery cells; and (ii) a pressure release sensor configured to sense a pressure release event caused by a pressure release device located within the housing.

[0086]

[0092] Example 20: The battery assembly of Example 18 or 19, wherein the information associated with the one or more sensed signals comprises digital signals transmitted to the system via a controller area network (CAN) bus, and the one or more sensed signals transferred to the system comprise analog discrete signals transmitted over a bus different from the CAN bus.

[0087]

[0093] The foregoing description of exemplary embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the disclosure be limited not by this detailed description, but rather by the claims appended hereto. Future applications claiming priority to this application may claim the disclosed subject matter differently and may generally include any set of one or more limitations as variously disclosed or otherwise demonstrated herein.

Claims

1. 1. A battery assembly comprising: The housing and an outgassing sensor within the housing, the outgassing sensor configured to sense an outgassing event of one or more battery cells within the housing and output a first sensing signal; a pressure relief device within the housing, the pressure relief device configured to release gas pressure from the housing in response to pressure within the housing exceeding a threshold; a pressure relief sensor within the housing, the pressure relief sensor configured to sense a pressure relief event caused by the pressure relief device and output a second sensing signal; a processor within the housing, the processor configured to receive the first sensing signal and the second sensing signal and to transmit information related to the first and second sensing signals to a system external to the housing.

2. 2. The battery assembly of claim 1, wherein the pressure relief device is a burst disc, and wherein the pressure relief event is a burst disc event in which a disc of the burst disc ruptures, and wherein the pressure relief sensor is a burst disc sensor configured to provide an indication of the burst disc event within the second sensed signal.

3. a plurality of battery cells within the housing, including the one or more battery cells; a switch within the housing, wherein the plurality of battery cells are coupled to a circuit external to the housing via the switch; 2. The battery assembly of claim 1, wherein the switch is configured to disconnect the plurality of battery cells from the circuit outside the housing in response to receiving a control signal generated in response to the first sensing signal indicating the outgassing event and / or the second sensing signal indicating the pressure release event.

4. The battery assembly of claim 3 , wherein the control signal is generated by the processor.

5. The battery assembly of claim 3 , wherein the control signal is generated by the system external to the housing and transmitted to the switch via the processor.

6. 4. The battery assembly of claim 3, wherein the control signal is generated by the system external to the housing and transmitted to the switch, bypassing the processor.

7. 10. The battery assembly of claim 1, wherein the processor is further configured to transfer the first and second sensing signals to an external system in addition to transmitting information associated with the first and second sensing signals to the external system.

8. the first and second sensed signals forwarded by the processor to the external system are analog discrete signals; 8. The battery assembly of claim 7, wherein the information related to the first and second sensed signals transmitted by the processor to the external system comprises a digital signal.

9. 2. The battery assembly of claim 1, wherein the information associated with the first sensing signal comprises an indication of the outgassing event, and the information associated with the second sensing signal comprises an indication of the pressure release event.

10. 10. The battery assembly of claim 1, wherein the information associated with the first sensing signal comprises a sensed concentration of outgassing and a timestamp of the outgassing event.

11. 10. The battery assembly of claim 1, wherein the outgassing sensor senses the outgassing event in response to detecting at least a threshold level of one or more gases emitted by the one or more battery cells.

12. 12. The battery assembly of claim 11, wherein the one or more gases comprise lithium ion battery electrolyte solvent vapor.

13. The battery assembly of claim 1 , wherein the one or more battery cells include one or more lithium ion battery cells.

14. the housing has a first wall and an opposing second wall; the processor is on a printed circuit board (PCB) mounted to the first wall; 10. The battery assembly of claim 1, wherein the pressure relief device is attached to the second wall such that, during the pressure relief event, pressure is released through an opening in the pressure relief device.

15. 1. A method of operating a battery assembly, the method comprising: outputting, by an outgassing sensor within the enclosure, a first sensing signal in response to monitoring a concentration of one or more gases from one or more battery cells within the enclosure; outputting, by a pressure relief sensor within the housing, a second sensed signal in response to monitoring operation of a pressure relief device within the housing; transmitting, by a processor within the housing, information related to the first and second sensed signals to a system external to the housing.

16. connecting a plurality of battery cells to a load external to the housing via a switch located within the housing, the plurality of battery cells being located within the housing and including the one or more battery cells; 16. The method of claim 15, further comprising: disconnecting, by the switch, the plurality of battery cells from the load in response to receiving a control signal generated in response to the first sensing signal indicative of an outgassing event and / or the second sensing signal indicative of a pressure relief event.

17. 17. The method of claim 16, further comprising generating the control signal based on monitoring first and second signals and / or the information related to the first and second sensed signals by the system external to the housing and / or by a processor system within the housing.

18. 1. A battery assembly comprising: The housing and a plurality of battery cells within the housing; one or more sensors configured to monitor one or more events associated with the plurality of battery cells; a processor within the housing, the processor configured to (i) receive the one or more sensed signals from the one or more sensors, (ii) transmit information related to the one or more sensed signals to a system external to the housing via a first communication link, and (iii) forward the one or more sensed signals to the system external to the housing via a second communication link different from the first communication link.

19. 20. The battery assembly of claim 18, wherein the one or more sensors comprise: (i) an outgassing sensor configured to sense an outgassing event of one or more battery cells among the plurality of battery cells; and (ii) a pressure release sensor configured to sense a pressure release event caused by a pressure release device located within the housing.

20. the information related to the one or more sensed signals comprises a digital signal transmitted to the system via a Controller Area Network (CAN) bus; 20. The battery assembly of claim 18, wherein the one or more sensed signals transferred to the system comprise analog discrete signals transmitted over a bus different from the CAN bus.

Images