Watertight marine battery

A marine battery system configured to provide energy to a marine vessel load is provided. The marine battery system includes a main enclosure body and an auxiliary enclosure body that is detachably coupled to the main enclosure body to define a sealed battery volume. The auxiliary enclosure body is configured to perform a pressure accommodation action responsive to an increase in a temperature within the sealed battery volume. The marine battery system further includes a battery disposed within the sealed battery volume.

FIELD

The present disclosure relates to battery systems for marine vessels, and particularly to systems and methods for detecting and mitigating adverse marine battery conditions.

BACKGROUND

U.S. Pat. No. 9,630,686 discloses a pressure tolerant energy system. The pressure tolerant energy system may comprise a pressure tolerant cavity and an energy system enclosed in the pressure tolerant cavity configured to provide electrical power to the vessel. The energy system may include one or more battery cells and a pressure tolerant, programmable management circuit. The pressure tolerant cavity may be filled with an electrically-inert liquid, such as mineral oil. In some embodiments, the electrically-inert liquid may be kept at a positive pressure relative to a pressure external to the pressure tolerant cavity. The energy system may further comprise a pressure venting system configured to maintain the pressure inside the pressure tolerant cavity within a range of pressures. The pressure tolerant cavity may be sealed to prevent water ingress.

U.S. Pat. No. 8,980,455 discloses a lithium-ion battery with a gas-releasing and explosion-proof safety valve, which comprises a casing and a battery core. The casing includes an opening that is sealed by a thermal cover, on which a safety valve is disposed. The safety valve comprises a safety cover and a pressure filter. A middle portion of the safety cover includes a through hole. The pressure filter is affixed to the middle portion of the safety cover and has numerous pores. The safety cover and thermal cover are hooked together. The present invention offers multiple advantages. Firstly, simplified structure without aging issue enhances the safety and reliability of the battery. Secondly, during operation, gas is ventilated when an internal pressure of the battery reaches a certain threshold value to avoid rupture of the battery casing. Thirdly, with enhanced performance of the battery, the cycle life of the battery is greatly increased.

U.S. Patent Application No. 2018/0013115 discloses a method for housing a battery used on a light-weight, motor powered watercraft includes the step of: providing a battery case having: a pod sized to house a marine battery, the pod having a cavity for the marine battery and an open top; a lid for at least water-resistant closure of the open top of the pod, the lid having a cavity and an open bottom, the lid is releasably attachable to the pod; and a floor releasably attached to the lid adjacent the open bottom, the floor adapted to hold controls for the light-weight, motor powered watercraft.

The above patents and patent publications are hereby incorporated by reference in their entireties.

SUMMARY

According to one implementation of the present disclosure, a marine battery system configured to provide energy to a marine vessel load is provided. The marine battery system includes a main enclosure body and an auxiliary enclosure body that is detachably coupled to the main enclosure body to define a sealed battery volume. The auxiliary enclosure body is configured to perform a pressure accommodation action responsive to an increase in temperature within the sealed battery volume.

According to another implementation of the present disclosure, a marine battery system for a marine vessel is provided. The marine battery system includes a battery, a main enclosure body, an auxiliary enclosure body that is detachably coupled to the main enclosure body, and a bladder that is disposed within the main enclosure body and the auxiliary enclosure body. The battery is fully encapsulated by the main enclosure body and the bladder within a sealed battery volume. An increase in a temperature within the sealed battery volume causes the bladder to expand within the auxiliary enclosure body to compensate for an increase in a pressure within the sealed battery volume.

According to another implementation of the present disclosure, a marine battery system for a marine vessel is provided. The marine battery system includes a battery, a main enclosure body, an auxiliary enclosure body that is detachably coupled to the main enclosure body, and a piston disposed within the auxiliary enclosure body. The battery is fully encapsulated by the main enclosure body and the auxiliary enclosure body within a sealed battery volume, and an increase in a temperature within the sealed battery volume causes the piston to slide within the auxiliary enclosure body and expand the sealed battery volume to compensate for an increase in a pressure within the sealed battery volume.

According to yet another implementation of the present disclosure, a method for operating a marine battery configured to provide energy to a marine vessel load is provided. The method includes receiving, at a battery management system for the marine battery, pressure information from a pressure sensor located in a sealed battery volume within a battery enclosure for the marine battery. The battery enclosure includes a main enclosure body and an auxiliary enclosure body. The method further includes receiving temperature information from a temperature sensor located in the sealed battery volume, comparing the pressure information and the temperature information, and determining whether an enclosure breach in the sealed battery volume has occurred based on a comparison of the pressure information and the temperature information.

DETAILED DESCRIPTION

In the present description, certain terms have been used for brevity, clearness and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes only and are intended to be broadly construed.

Vessel electrification and the application of electric propulsion systems and Lithium Ion battery technology for electrical energy storage creates a different set of hazards than traditional internal combustion engines and liquid fuel storage. Additional hazards are created when current technology Lithium Ion (Li-ion) batteries with liquid organic electrolyte come in contact with water. The inventor has recognized that particular issues may arise relating to battery conditions on marine vessels and other marine-related electrical energy storage with current technology lithium ion batteries because boaters may be on open water and/or not be able to reach a safe location in event of a battery fire or other hazardous battery event. In addition, Li-ion batteries in marine applications are at particular risk because the humid and salty environments are not conducive to long battery life. Thus, the inventor has recognized a need for a marine battery system with sealed battery compartments and monitoring methods that provide detection and mitigation of potential hazards of a battery electric drive system in a marine application. The innovative concepts are applicable to broad range of battery applications beyond the marine industry.

FIG.1depicts an embodiment of an electric marine propulsion system2powered by a storage system16, such as a Li-ion battery pack. In the depicted embodiment, the electric marine propulsion system2includes an outboard marine drive3having an electric motor4housed therein, such as housed within the cowl50of the outboard marine drive. A person of ordinary skill in the art will understand in view of the present disclosure that the marine propulsion system2may include other types of electric marine drives, such as inboard drives or stern drives. The electric marine drive3has an electric motor4configured to propel the marine vessel1by rotating a propeller10. The motor4may be, for example, a brushless electric motor, such as a brushless DC motor. In other embodiments, the electric motor may be a DC brushed motor, an AC brushless motor, a direct drive, a permanent magnet synchronous motor, an induction motor, or any other device that converts electric power to rotational motion. In certain embodiments, the electric motor4includes a rotor and a stator, as is well known in the relevant art.

The electric motor4is electrically connected to and powered by a power storage system16. The power storage system16stores energy for powering the electric motor4and is rechargeable, such as by connection to shore power when the electric motor4is not in use. Various power storage systems16are known in the art and are suitable for powering an electric marine drive, such as various Li-ion battery pack arrangements. In the depicted example, a bank or group of cell modules18is connected in series to provide a large voltage output. For example, the battery system may include multiple cell modules18, such as 4-7 cell modules, each being a 50 V storage unit, which may be arranged in series to provide a high voltage output. Each cell module18, or storage section, is comprised of multiple battery cells.

The power storage system16may further include a battery management system (BMS)60configured to monitor and/or control aspects of the power storage system16. For example, the BMS60may receive inputs from one or more sensors within or on the power storage system16, such as an integrated management module (IMM), one or more temperature sensors configured to sense temperature at location(s) within the battery pack enclosures (seeFIGS.2-4), one or more pack internal pressure sensors configured to sense pressure at location(s) within the enclosure, a water sensor configured to sense water ingress or to sense water on the exterior of the enclosure, a humidity sensor configured to sense humidity within the enclosure, and electrolysis gas sensors configured to sense the presence of gas (e.g., hydrogen gas) indicating that electrolysis is occurring. The system is configured to determine a battery state of health and to recognize a hazardous condition based on any one or more of the sensor measurements. The BMS60may further be configured to receive information from current, voltage, and/or other sensors within the power storage system16, such as to receive information about the voltage, current, and temperature of each battery cell and/or each cell module18within the power storage system16.

The central controller12, which in the depicted embodiment is a propulsion control module (PCM), communicates with the motor controller14via communication link34, such as a CAN bus. The controller also receives input from and/or communicates with one or more user interface devices in a user interface system35via the communication link, which in some embodiments may be the same communication link as utilized for communication between the controllers12,14,20or may be a separate communication link. The user interface devices in the exemplary embodiment include a throttle lever38and a display40. In various embodiments, the display40may be, for example, part of an onboard management system, such as the VesselView™ by Mercury Marine of Fond du Lac, Wisconsin. The user interface system35may also include a steering wheel36, which in some embodiments may also communicate with the controller12in order to effectuate steering control over the marine drive3, which is well-known and typically referred to as steer-by-wire arrangements. In the depicted embodiment, the steering wheel36is a manual steer arrangement where the steering wheel36is connected to a steering actuator that steers the marine drive3by a steering cable37.

Each electric motor4may be associated with a motor controller14configured to control power to the electric motor, such as to the stator winding thereof. The motor controller14is configured to control the function and output of the electric motor4, such as controlling the torque outputted by the motor, the rotational speed and direction of the motor4, as well as the input current, voltage, and power supplied to and utilized by the motor4. In one arrangement, the motor controller14controls the current delivered to the stator windings via the leads15, which input electrical energy to the electric motor to induce and control rotation of the rotor. Sensors may be configured to sense the power, including the current and voltage, delivered to the motor4. The motor controller14is configured to provide appropriate current and or voltage to meet the demand for controlling the motor4. For example, a demand input may be received at the motor controller14from the central controller12, such as based on an operator demand at a helm input device, such as the throttle lever38.

Turning now toFIG.2, a sealed battery enclosure200is depicted. The sealed battery enclosure200may be incorporated into any of the cell modules18depicted inFIG.1. The sealed battery enclosure200is shown to include an enclosure body202that defines the boundaries for a sealed battery volume204. In various embodiments, the enclosure body202may be fabricated from a metal (e.g., aluminum or aluminum alloy, steel), plastic, or composite material. The enclosure body202may further include various sealing gaskets and/or impermeable coatings in order to achieve a desired enclosure impermeability and provide a hermetic environment within the sealed battery volume204.

A battery cell or cells (not shown) may be positioned within the sealed battery volume204and may include all the typical components of a battery cell, namely, a cathode, an anode, an electrolyte, and a separator. In an exemplary implementation, the battery cell includes intercalated lithium compound utilized as the cathodic material and graphite utilized as the anodic material.

A temperature sensor206and a pressure sensor208are shown to be coupled to an upper wall of the battery enclosure200. The temperature sensor206is configured to detect temperature information (e.g., temperature measurements) within the sealed battery volume204. The temperature sensor206may be any suitable type of temperature sensor (e.g., a thermocouple, a resistance temperature detector (RTD), a thermistor, a semiconductor-based integrated circuit) and is not particularly limited. The pressure sensor208is configured to detect pressure information (e.g., pressure measurements) within the sealed battery volume204. The pressure sensor208may be any suitable type of pressure sensor and is not particularly limited. In an exemplary implementation, the pressure sensor208is configured to measure absolute pressure within the sealed battery volume204. As described in further detail below with reference toFIGS.5and6, the temperature sensor206and the pressure sensor208may be utilized in concert to detect breaches in the sealed battery volume204.

The battery enclosure200is further shown to include a desiccant210located within the sealed enclosure volume204. Although Li-ion batteries are generally manufactured in humidity-controlled settings, the presence of the desiccant210can ensure any water contamination introduced into the sealed enclosure volume204during the manufacturing process is absorbed and/or adsorbed. The desiccant210may be replaced any time the battery enclosure200is serviced or any time the sealed enclosure volume204is breached to remove any moisture that is introduced during these processes. The characteristics of the desiccant210are not particularly limited. For example, in various embodiments, the desiccant210may include silica gel, molecular sieves (zeolites), or activated alumina.

The battery enclosure200further includes a pressure relief valve212. The pressure relief valve212is configured to remain closed under nominal conditions and to open to vent air from within the sealed enclosure volume204if a pressure safety threshold within the sealed enclosure volume204is exceeded to prevent catastrophic housing failure. In some implementations, the pressure relief valve212includes a membrane that permits air to flow through the pressure relief valve212when it is in the opened position, but does not permit water to enter the sealed enclosure volume204through the pressure relief valve212. As described in further detail below with reference toFIG.6, based on the pressure information received from the pressure sensor208, the BMS60and/or the central controller12may be configured to detect if the pressure relief valve212is malfunctioning and to perform appropriate mitigation actions in the event of a detected malfunction.

Referring now toFIG.3, a sealed battery enclosure300with an expandable bladder system is depicted. The sealed battery enclosure300may be incorporated into any of the cell modules18depicted inFIG.1. In contrast to the enclosure200depicted inFIG.2, the sealed battery enclosure300is shown to include both a main enclosure body302and an auxiliary enclosure body314. The main enclosure body302defines a first battery volume304, and the auxiliary enclosure body314defines a second battery volume324. As described in further detail below, the maximum sealed volume available to a battery cell or cells disposed within the battery enclosure300is the sum of the first battery volume304and the second battery volume324.

In an exemplary implementation, the auxiliary enclosure body314is detachably coupled to the main enclosure body302. The coupling between the main and auxiliary enclosure bodies302,314may be achieved using a suitable sealed coupling mechanism, for example, a threaded connection, male and female mating connectors with o-ring seals, etc. In some implementations, the auxiliary enclosure body314may not be directly coupled to the main enclosure body302. Instead, the auxiliary enclosure body314may be located remotely from the main enclosure body302, and the bodies302,314may be connected by a tube or conduit. The present inventor has recognized that by permitting the auxiliary enclosure body314to be detached from the main enclosure body302, the serviceability of the sealed battery enclosure300is improved. For example, if an enclosure breach occurs, the auxiliary enclosure body314may be detached from the main enclosure body302in order to service the battery. The auxiliary enclosure body314can also be replaced with a new or repaired auxiliary enclosure body314. In this way, the battery system is serviceable and the lifespan of the sealed battery enclosure300may be extended.

An expandable bladder316is shown to be located at least partially within the auxiliary enclosure body314. In various implementations, the bladder316may extend into the main enclosure body302such that the battery cells disposed within the sealed battery enclosure300are encapsulated by the main enclosure body302and the bladder316. As shown inFIG.3, prior to operation of the battery cells and/or when the battery enclosure300is located in a cold or moderate temperature environment, the bladder316may be deflated or only partially inflated. However, as the battery cells positioned within the main sealed battery volume304heat up due to operation of the cells or an increase in environmental temperature, electrolysis gas318builds up within the main enclosure body302. This electrolysis gas318causes the bladder316to inflate within the auxiliary enclosure body314, up to a maximum volume represented by the second battery volume324. In other words, the bladder316may expand to substantially fill the entire volume324of the auxiliary enclosure body314. As the bladder316inflates within the auxiliary enclosure body314, the bladder316displaces air322located within the second battery volume324, which is forced out of the enclosure body314through a vent opening320. In an exemplary implementation, the vent opening320includes a membrane that permits air322to flow through the vent320, but does not permit water to enter the auxiliary enclosure body314.

The bladder316may be fabricated from any material that is sufficiently flexible to inflate due to the build up of electrolysis gas and sufficiently strong to resist failure due to breach.

The sealed battery enclosure300is further shown to include a temperature sensor306, a pressure sensor308, a desiccant310, and a pressure relief valve312. Each of these components may be identical or substantially similar to sensors206,208, desiccant210, and pressure relief valve212, depicted and described above with reference toFIG.2. Although the desiccant310is shown to be positioned within the main enclosure body302, in other implementations, the desiccant310may be located within the auxiliary enclosure body314. In still further implementations, both the main enclosure body302and the auxiliary enclosure body314include a desiccant310.

Turning now toFIG.4, a sealed battery enclosure400with a piston system is depicted. The sealed battery enclosure400may be incorporated into any of the cell modules18depicted inFIG.1. Similar to the enclosure300depicted inFIG.3, the sealed battery enclosure400is shown to include both a main enclosure body402that defines a first battery volume404and an auxiliary enclosure body414that defines a second battery volume424. The auxiliary enclosure body414is detachably coupled to the main enclosure body402using any suitable coupling mechanism. In this way, the auxiliary enclosure body414can be serviced or replaced in the event of an enclosure breach or component failure within the auxiliary enclosure body414.

The auxiliary enclosure body414is shown to include a slidable piston416that is configured to move horizontally as indicated by the arrow422. In an exemplary implementation, the piston416is generally disc-shaped, and an O-ring seal or gasket430may be situated around the circumference of the piston416to prevent the flow of air past the piston416and to provide a sealed volume for the battery cells. The piston416is coupled to a spring418that is configured to bias the piston416toward the main enclosure body402prior to operation of the battery cells and/or when the battery enclosure400is located in a cold or moderate temperature environment. As the cells heat up due to operation of the cells or an increase in environmental temperature, electrolysis gas426builds up within the main enclosure body402. The electrolysis gas426compresses the spring418, thus causing the piston416to slide outwardly and increase the sealed volume used to encapsulate the battery cells. Since the spring force provided by the spring418acts to bias the piston416toward the main enclosure body402and counteract the force exerted by the gas426on the piston416, the spring constant, or stiffness associated with the spring418can have a significant effect on the internal pressure of the sealed battery volume. In other words, a spring418with a relatively high spring constant requires a greater force to be exerted by the gas426upon the piston416to compress the spring418and expand the volume available to the battery cells as compared with a relatively low spring constant.

As the piston416moves outwardly within the auxiliary enclosure body414, the piston416displaces air428which is forced out of the enclosure body414through a vent opening420. In an exemplary implementation, the vent opening420includes a membrane that permits air428to flow through the vent opening420, but does not permit water to enter the auxiliary enclosure body414.

Similar to the battery enclosure300depicted inFIG.3, the sealed battery enclosure400is further shown to include a temperature sensor406, a pressure sensor408, a desiccant410, and a pressure relieve valve412. Each of these components may be identical or substantially similar to sensors206,208, desiccant210, and pressure relief valve212, depicted and described above with reference toFIG.2. Although the desiccant410is shown to be positioned within the auxiliary enclosure body414, in other implementations, the desiccant410may be located within the main enclosure body402. In still further implementations, both the main enclosure body402and the auxiliary enclosure body414include a desiccant410.

FIG.5depicts a plot500correlating ideal temperature and pressure data collected by the sensors (i.e., temperature sensors206,306,406, pressure sensors208,308,408) of the sealed battery enclosures200,300,400. The horizontal axis502is shown to depict the temperature inside the sealed portions of the enclosures in degrees Celsius, while the vertical axis504is shown to depict the pressure inside the sealed portions of the enclosures in pound-force per square inch (psi).

Line506depicts the behavior of the battery enclosure200, depicted inFIG.2. At a minimum temperature of −20° C. inside the enclosure, the pressure inside the enclosure is at a minimum of approximately 12.5 psi. The data506exhibits a linear relationship up to a maximum temperature of 100° C. and a maximum pressure of approximately 18.5 psi

Line segments508and510depict the behavior of the battery enclosure300with the bladder system, depicted inFIG.3. Specifically, line segment508depicts the behavior of the enclosure300as the bladder316inflates, and line segment510depicts the behavior once the bladder316has fully expanded. As shown, during the period of bladder inflation, even though the temperature inside the enclosure is increasing (i.e., from −20° C. to 40° C.), the pressure inside the battery does not correspondingly increase and remains at the minimum of 12.5 psi. This is due to the increase in volume provided by the bladder316accommodating the expansion of the electrolysis gases318that would otherwise increase the pressure in the enclosure300. However, once the bladder316has fully expanded, the electrolysis gases318continue to expand and increase the pressure within the enclosure300up to a maximum pressure of approximately 15.5 psi at the maximum temperature of 100° C.

As depicted inFIG.5, during the period of pressure increase (depicted as line segment510), the pressure within the enclosure300increases at approximately the same rate as the pressure within the enclosure200(depicted as line segment506). Notably, the maximum pressure of the enclosure300is less than the maximum experienced by the enclosure200, which does not include any pressure mitigation features. Detection of enclosure breaches within the enclosure300(described in further detail below with reference toFIG.6) may occur during the period of pressure increase (depicted as line segment510). For example, if a controller receiving pressure and temperature information from the sensors306,308within the enclosure300determines that the temperature is above 40° C. and the pressure has not correspondingly risen above 12.5 psi, the controller may perform an enclosure breach mitigation action that includes displaying a warning on the display40(depicted inFIG.1) and/or shutting the battery down.

Lines512and514depict the behavior of the battery enclosure with the piston system400, depicted inFIG.4. Specifically, line512depicts the battery enclosure400with a spring418having a relatively higher spring constant, and line514depicts the battery enclosure400with a spring418having a relatively lower spring constant. Accordingly, the enclosure400with the higher spring constant experiences a higher maximum pressure (approximately 16 psi), while the enclosure400with the lower spring constant experiences a lower maximum pressure (approximately 14 psi). Notably, both implementations of the enclosure400experience a lower maximum pressure than the enclosure200, which includes no pressure mitigation features. Furthermore, in contrast to the enclosure300with the bladder system, the enclosure400with the piston system permits the detection of enclosure breaches across the entire temperature spectrum due to the expected linear correlation between pressure and temperature through the complete temperature range.

Referring now toFIG.6, a process600is depicted for detecting enclosure breach or pressure relief valve fault conditions. According to an exemplary implementation of the present disclosure, process600may be performed at least in part by the BMS60or the central controller12, depicted inFIG.1. For the purposes of simplicity, process600will be described below exclusively with reference to the BMS60.

Process600is shown to commence with step602, in which the BMS60receives temperature information from a temperature sensor (e.g., temperature sensor206,306,406). At step604, the BMS60receives pressure information from a pressure sensor (e.g., pressure sensor208,308,408). In some implementations, the BMS60receives the temperature information and the pressure information at specified intervals of time (e.g., one temperature measurement from the temperature sensor206and one pressure measurement from the pressure sensor208every five seconds). In other implementations, the BMS60receives pressure and temperature measurements from the sensors in a generally continuous manner.

At step606, the BMS60determines whether an enclosure breach condition has occurred. As depicted inFIG.5, in most circumstances, there is a positive linear correlation between pressure and temperature measurements for a properly sealed battery enclosure. (Note: the exception to this positive correlation is depicted herein by line segment508for the sealed battery enclosure300, in which the period of inflation of the bladder316does not result in a corresponding increase in pressure during an increase in temperature.)

If, at step606, the BMS60determines that the temperature and pressure information indicates that an enclosure breach condition has occurred, process600may proceed to step608and the BMS60may perform an enclosure breach mitigation action. Because an enclosure breach can result in water intrusion, which can in turn lead to a thermal runaway event, the present inventor has recognized the advantages of alerting a user to the existence of an enclosure breach prior to water intrusion. In some implementations, the enclosure breach mitigation action may include the BMS60transmitting a message (e.g., to central controller12) to be displayed on a user device (e.g., display40) indicating a battery enclosure breach. This message may prompt the user to inspect and service the battery, if possible. For example, user inspection of the battery may reveal that the enclosure breach has occurred within an auxiliary enclosure body, prompting the user to detach the auxiliary enclosure body for repair or complete replacement In further implementations, the BMS60may disconnect the affected battery from the power storage system16. A severity of the enclosure breach may be determined based on an error between expected temperature and pressure values and the received temperature and pressure information. In some implementations, the BMS60performs both actions. Once the BMS60has performed the enclosure breach mitigation action or actions, process600reverts to step602.

Returning to step606, if the BMS60does not determine that the temperature and pressure information indicates that an enclosure breach condition has occurred, process600proceeds to step610. At step610, the BMS60determines whether a pressure safety threshold has been exceeded based on the pressure information received from the pressure sensor (e.g., pressure sensor208,308,408). If a pressure safety threshold is exceeded within the battery enclosure, this may indicate a fault in the pressure relief valve (e.g., pressure relief valve212,312,412), and the BMS60may perform a pressure relief valve fault mitigation action in step612. In some implementations, the fault mitigation action may include the BMS60transmitting a message to be displayed on a user device (e.g., display40) indicating a pressure relief valve fault. If the pressure information from the pressure sensor is sufficiently high to indicate imminent damage to the battery, the BMS60may disconnect the affected battery from the power storage system16. Once the BMS60has performed the pressure relief valve fault mitigation action or actions, process600concludes by reverting to step602, as the BMS60continues to receive pressure and temperature information from the temperature and pressure sensors.

Turning now toFIG.7, a process700is depicted for detecting enclosure breaches or pressure relief valve fault conditions. In some implementations, process700is performed during step606of process600depicted inFIG.6. According to an exemplary implementation of the present disclosure, process700may be performed at least in part by the BMS60or the central controller12, depicted inFIG.1. For the purposes of simplicity, process700will be described below exclusively with reference to the BMS60.

Process700commences with step702, in which the BMS60receives or retrieves an allowable pressure deviation. The allowable pressure deviation refers to amount in which a pressure measurement may deviate from an expected or ideal value for the given temperature (e.g., the data depicted in plot500ofFIG.5) before a fault is detected. The allowable pressure deviation may vary based on characteristics of the battery or may be configurable by an operator. In some implementations, the allowable pressure deviation is in the form of a pressure value, for example, ±0.5 psi or ±1.0 psi. In other implementations, the allowable pressure deviation is in the form of a percentage, for example, ±10% or ±15%.

At step704, the BMS60retrieves the expected pressure measurement for the measured temperature value. The measured temperature value may be received from the temperature sensor (e.g., temperature sensor206,306,406) at step602of process600. The expected pressure measurement is based on the ideal data. For example, referring toFIG.5, if the battery enclosure includes a bladder system (e.g., battery enclosure300), and the temperature sensor306indicates that the measured temperature is 60° C., the expected pressure value is 13.5 psi. Accordingly, if the allowable pressure deviation is ±10%, the allowable pressure range is 12.15 psi to 14.85 psi.

At step706, the BMS60determines whether the measured pressure is lower than the lower boundary of the expected range. The measured pressure value may be received from the pressure sensor (e.g., pressure sensor208,308,408) at step604of process600. Returning to the example above, step706is satisfied if the measured pressure value is less than 12.15 psi. Process700then proceeds to step708, as an enclosure breach condition is detected. As described above with reference to step608ofFIG.6, detection of an enclosure breach condition may prompt the BMS60to perform an enclosure breach mitigation action.

If, at step706, the BMS60determines that the measured pressure is not lower than the lower boundary of the pressure range, process700proceeds to step710, in which the BMS60determines whether the measured pressure is higher than the upper boundary of the expected range. Returning to the example above, step710is satisfied if the measured pressure value is greater than 14.85 psi. Process700then proceeds to step712, as a failure condition is detected. Examples of a fault condition in which a higher than expected measured pressure value is received may include a failure of the bladder316to properly inflate, or a failure of the piston416to slide within the auxiliary enclosure body414. Alternatively, the high pressure may be caused by another failure mode. In response to detection of the fault condition at step712, the BMS60may transmit a warning or failure alert message (e.g., to central controller12) to be displayed on a user device (e.g., display40) and/or may disconnect the affected battery from the power storage system16. However, if the BMS60determines at step710that the measured pressure is not higher than the upper boundary of the pressure range, then the measured pressure is within the expected pressure range, and process700terminates by reverting to step702.

In the present disclosure, certain terms have been used for brevity, clearness and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes only and are intended to be broadly construed. The different systems and methods described herein may be used alone or in combination with other systems and devices. Various equivalents, alternatives and modifications are possible within the scope of the appended claims.