Energy storage system employing a suppression system and thermal runaway suppression method

Abstract

An energy storage system (ESS) comprises a cabinet; at least one battery string within the cabinet, the at least one battery string comprising a plurality of battery modules; and a suppression system within the cabinet configured to monitor a plurality of ESS conditions and to condition the ESS in a staged manner as monitored ESS conditions escalate as a result of a potential ESS failure event.

Description

ENERGY STORAGE SYSTEM EMPLOYING A SUPPRESSION SYSTEM AND THERMAL RUNAWAY SUPPRESSION METHODCross- Reference To Related ApplicationThe subject application claims the benefit of U.S. Provisional Application No. 63 / 558,926 filed on February 28, 2024, the entire content of which is incorporated herein by reference.Field of the Invention

[0001] The subject disclosure is directed to an energy storage system employing a suppression system and to a thermal runaway suppression method.Background

[0002] It is well documented that the transportation sector accounts for a quarter of global greenhouse gas (GHG) emissions, with forecasts trending upward. Left unmitigated, mobility-related GHG emissions could increase more rapidly than any other end-use energy sector, reaching around 12 Gt CO2eq / yr by 2050. Incentivized by climate change mitigation and an ever-growing need for sustainability, researchers, stakeholders, and policymakers have committed to significant electrification of the transportation industry.

[0003] Advances in electric vehicle (EV) technology are driven by the need for (i) increased battery capacities (higher range), (ii) increased battery voltages (higher power), and (iii) increased on-board and off-board charging power (higher charging rates). These advances aim to reduce charging times and extend the driving range of EVs to make them more competitive with internal combustion engine vehicles (ICEVs). However, gasoline refueling of ICEVs is estimated to provide ICEVs with 5000 kW of power, while the most advanced EV chargers to date provide EVs with only 500 kW of power. As will be appreciated, scaling the EV ecosystem to achieve charging rates comparable with ICEV gasoline refueling imposes significant thermal constraints on the batteries and chargers.

[0004] Moreover, redesigning infrastructure is critical to support the global transportation industry's electrification efforts. On the off-board charging front, condominiums in many high-density cities are required to include both level-2 and level- 3 charging (19.2 kW - >100 kW) in underground parking lots to supplement the lack ofcharging infrastructure currently available. To achieve this cost-effectively, energy storage systems will have to be deployed underground. However, deploying such energy storage systems underground poses a significant safety concern for many parties such as developers, city planners, contractors, civil engineers, provincial building code committees etc. This is due to the fact that Lithium-ion and other rare earth batteries can fail catastrophically and violently (commonly referred to as “runaway”), resulting in significant heat, flames, electrical shorting, and emission of toxic high- velocity gases. As a result, deploying energy storage systems in underground environments requires appropriate safety measures to combat thermal runaway should an energy storage system failure event occur.

[0005] Although fire protection systems for lithium-ion and other rare earth battery energy storage systems exist, improvements to inhibit thermal runaway are desired. It is therefore an object to provide a novel energy storage system employing a suppression system and a novel thermal runaway suppression method.

[0006] This background serves only to set a scene to allow a person skilled in the art to better appreciate the following brief and detailed descriptions. Therefore, none of the above discussion should necessarily be taken as an acknowledgement that this background discussion is part of the state of the art or is common general knowledge.Brief Description

[0007] It should be appreciated that this Brief Description is provided to introduce a selection of concepts in a simplified form that is further described below in the Detailed Description. This Brief Description is not intended to limit the scope of claimed subject matter.

[0008] Accordingly, in one aspect there is provided an energy storage system (ESS) comprising: a cabinet; at least one battery string within the cabinet, the at least one battery string comprising a plurality of battery modules; and a suppression system within the cabinet configured to monitor a plurality of ESS conditions and to condition the ESS in a staged manner as monitored ESS conditions escalate as a result of a potential ESS failure event.

[0009] In one or more embodiments, the suppression system is configured to: monitor ESS conditions at a cabinet level; monitor ESS conditions at a battery module level; or monitor ESS conditions at both cabinet and battery module levels.

[0010] In one or more embodiments, the ESS conditions monitored at the cabinet level comprise two or more of temperature, humidity, presence of smoke, presence of hydrogen, and presence of hydrocarbons.

[0011] In one or more embodiments, the ESS conditions monitored at the battery module level comprise temperature and voltage.

[0012] In one or more embodiments, the suppression system is configured to condition the ESS to an initial shutdown mode in response to at least one of a sensed temperature, humidity, or voltage reaching an initial threshold value. In one aspect, the sensed temperature is at least one of a sensed ambient temperature within the cabinet reaching the initial threshold value and a sensed temperature within a battery module reaching the initial threshold value. The initial threshold value is in the range of from about 45°C to about 80°C.

[0013] In one or more embodiments, the sensed humidity is a sensed relative humidity within the cabinet reaching the initial threshold value. In one aspect, the initial threshold value is 90% relative humidity or greater.

[0014] In one or more embodiments, the sensed voltage is a voltage within a battery module reaching the initial threshold value. In one aspect, the initial threshold value is in the range of 4.2V to 4.3V.

[0015] In one or more embodiments, in the initial shutdown mode, input power to and output power from the ESS is terminated.

[0016] In one or more embodiments, the suppression system is conditioned to an alarm mode in response to at least one of the sensed temperature or voltage reaching an upper threshold value above initial threshold value. In one aspect, the upper threshold value is a sensed temperature equal to or exceeding 80°C or a sensed voltage greater than or equal to 4.3V.

[0017] In one or more embodiments, the suppression system initiates a plurality of preventative actions in the alarm mode. In one aspect, in the alarm mode the suppression system is configured to at least one of: prime a suppressant agent delivery system configured to deliver a suppressant agent to the battery modules; activate visual and / or audio alarms; automatically initiate calls to local fire department(s) and / or key personnel; and disable the battery modules.

[0018] In one or more embodiments, the ESS further comprises the suppressant agent delivery system, wherein the suppressant agent delivery system comprises a conduit network connected to at least one pressurized suppression agent tank, theconduit network extending to each of the battery modules and comprising sprinkler heads extending into the battery modules.

[0019] In one or more embodiments, each sprinkler head is configured to automatically trigger to deliver suppression agent to an associated battery module when the temperature in the associated battery module reaches a critical threshold value.

[0020] According to another aspect there is provided a method of suppressing thermal runaway in an energy storage system (ESS) comprising at least one battery string have a plurality of battery modules and accommodated by a cabinet, the method comprising: monitoring, using sensors, a plurality of environmental conditions of the ESS; and in the event of a potential ESS failure event, take preventative actions in a predictive manner as monitored environmental conditions of the ESS signify escalation of the ESS failure event.

[0021] In one or more embodiments, the monitoring comprises monitoring environmental conditions of the ESS at a battery module level and at a cabinet level. In one aspect, the monitoring at the battery module level comprises monitoring battery module temperature and voltage. In another aspect, the monitoring at the cabinet level comprises monitoring at least one of temperature, relative humidity, presence of gas, and presence of smoke within the cabinet. The monitoring presence of gas within the housing may comprise monitoring for the presence of hydrogen and / or hydrocarbons.

[0022] In one or more embodiments, in the event of a potential ESS fire event, the method further comprises at least one of: priming a suppressant agent delivery system configured to deliver a suppressant agent to the battery modules; activating visual and / or audio alarms; automatically initiating calls to local fire department(s) and / or key personnel; and disabling the battery modules.Brief Description of the Drawings

[0023] Embodiments will now be described more fully with reference to the accompanying drawings in which:

[0024] Figures 1 and 2 are isometric views of an energy storage system (ESS) employing a suppression system in accordance with the subject disclosure;

[0025] Figure 3 is another isometric view of the ESS of Figures 1 and 2 with the ESS cabinet walls transparent to show the interior of the ESS cabinet;

[0026] Figure 4 is a fragmentary view of an ESS cabinet interior side wall showing a spring-loaded vent cover in a closed condition;

[0027] Figure 5 is a top plan view of the ESS of Figures 1 and 2 with the ESS cabinet top wall removed and with empty battery module support racks;

[0028] Figure 6 is a cross-sectional view of the ESS of Figure 5 taken along line 6-6;

[0029] Figure 7 is a cross-sectional view of the ESS of Figure 5 taken along line 7-7;

[0030] Figure 8 is a cross-sectional view of the ESS of Figure 5 taken along line 8-8;

[0031] Figures 9 and 10 are perspective views of an ESS battery module with the battery module casing walls transparent to show the interior of the battery module;

[0032] Figure 11 is a top plan view of the interior of the battery module of Figures 9 and 10;

[0033] Figure 12 is a perspective view of the battery module interior of Figure 11 ;

[0034] Figure 13 is a fragmentary view of the battery module interior of Figure 11 showing a thermistor mounted on an interconnect board;

[0035] Figure 14 is another fragmentary view of the battery module interior of Figure 11 showing battery management system (BMS) connectors;

[0036] Figure 15 is a partial perspective view of a battery module supported on one of the support racks and showing a branch line and dry sprinkler head of an ESS suppression system;

[0037] Figure 16 is an electrical schematic layout of ESS suppression system components; and

[0038] Figure 17 is a flow diagram showing logic of a thermal runaway suppression strategy employed by the ESS suppression system.Detailed Description

[0039] The foregoing summary and the following detailed description of certain examples will be better understood when read in conjunction with the appended drawings. As used herein, an element or feature introduced in the singular and preceded by the word "a" or "an" should not necessarily exclude the plural of the elements or features. Further, references to "one example" or “one embodiment” are not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the described elements or features. Moreover, unless explicitly stated to the contrary, examples or embodiments "comprising" or "having" or “including” an element or feature or a plurality of elements or features having a particular property may include additional elements or features not having that property. Also, it will be appreciated that the terms “comprises,” “has,” and “includes”means “including but not limited to,” and the terms “comprising,” “having,” and “including” have equivalent meanings.

[0040] As used herein, the term “and / or” can include any and all combinations of one or more of the associated listed elements or features.

[0041] It will be understood that when an element or feature is referred to as being “on,” “attached” to, “affixed” to, “connected” to, “coupled” with, “contacting,” etc., another element or feature, that element or feature can be directly on, attached to, connected to, coupled with, or contacting the other element or feature or intervening elements may also be present. In contrast, when an element or feature is referred to as being, for example, “directly on,” “directly attached” to, “directly affixed” to, “directly connected” to, “directly coupled” with, or “directly contacting” another element of feature, there are no intervening elements or features present.

[0042] It will be understood that spatially relative terms, such as “under,” “below,” “lower,” “over,” “above,” “upper,” “front,” “back,” and the like, may be used herein for ease of description to describe the relationship of an element or feature to another element or feature as illustrated in the figures. However, the spatially relative terms can encompass different orientations in use or operation in addition to the orientation depicted in the figures.

[0043] Reference herein to “example” means that one or more feature, structure, element, component, characteristic, and / or operational steps described in connection with the example is included in at least one embodiment and / or implementation of the subject matter according to the subject disclosure. Thus, the phrases “an example,” “another example,” and similar language throughout the subject disclosure may not necessarily refer to the same example. Further, the subject matter characterizing any example may, but does not necessarily, include the subject matter characterizing any other example.

[0044] Reference herein to “configured” denotes an actual state of configuration that fundamentally ties the element or feature to the physical characteristics of the element or feature preceding the phrase “configured to.”

[0045] Unless otherwise indicated, the terms “first,” “second,” etc., are used herein merely as labels and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of a lower-numbered item (e.g., a “first” item) and / or a higher-numbered item (e.g., a “third” item).

[0046] As used herein, “approximately,” “about,” substantially, etc., represent an amount close to the stated amount that still performs the desired function or achieves the desired result. For example, the terms “approximately,” “about,” “substantially,” etc. may refer to an amount that is within engineering tolerances that would be readily appreciated by a person skilled in the art.

[0047] In general, an energy storage system (ESS) is disclosed. The ESS comprises a cabinet and at least one battery string within the cabinet. The at least one battery string comprises a plurality of battery modules. A suppression system is provided within the cabinet and is configured to monitor a plurality of ESS conditions and to condition the ESS in a staged manner as monitored ESS conditions escalate as a result of a potential ESS failure event. Further specifics of the ESS and its suppression system will now be described with reference to the Figures 1 to 17.

[0048] Turning now to Figures 1 to 3, an energy storage system (ESS) is shown and is generally identified by reference numeral 100. In this embodiment, the ESS 100 comprises an outer cabinet or housing 102. The cabinet 102 in this example is generally rectangular in plan and includes top and bottom walls 104 and 106, opposed side walls 108, and a rear wall 110. The front wall 112 of the cabinet 102 is defined by a pair of doors 112a that can be opened to expose the interior of the cabinet 102. Those of skill in the art will appreciate that other cabinet configurations may be employed.

[0049] In this embodiment, each side wall 108 comprises a pair of side wall panels 108a. Each side wall panel 108a has a vent therein adjacent the cabinet top wall 104 that is covered by a spring-loaded vent panel 114 hingedly connected to the interior surface of the side wall panel 108a. As can be seen in Figure 4, spring mechanisms 116 that are fastened to the interior surfaces of the side wall panels 108a and to the vent panels 114 apply an outward bias on the vent panels 114. Releasable latch mechanisms 118 mounted to the interior surfaces of the side wall panels 108a retain the vent panels 114 in a closed condition against the bias.

[0050] T urning now to Figures 3 and 5 to 8, the interior of the cabinet 102 is better illustrated. In this embodiment, the cabinet 102 accommodates a plurality of battery module support racks configured to support arrays of battery modules. In particular, the cabinet 102 accommodates support racks 120 and 122 adjacent the opposite side walls 108 of the cabinet 102 and support racks 124 and 126 adjacent the front and rear walls 112 and 110 of the cabinet 102. Those of skill in the art will appreciate that dependingon the size of the cabinet 102, more or fewer support racks may be accommodated by the cabinet 102.

[0051] In this embodiment, the support rack 120 is configured to accommodate a first battery string 130, the support rack 122 is configured to accommodate a second battery string 132, and the support racks 124 and 126 are configured to accommodate a third battery string 134. Those of skill in the art will appreciate that that the cabinet 102 may be configured to accommodate more or fewer battery strings depending on the ESS power requirements and the size of the cabinet 102.

[0052] Each battery string 130, 132, and 134 comprises an array of battery modules 140 with the battery modules 140 of each battery string being electrically connected in series. In this example, each array of battery modules 140 is a 4x4 array and thus, comprises four (4) rows and four (4) columns of battery modules 140. Support racks 120 and 122 are sized to support the entire battery module array of battery strings 130 and 132. Support racks 124 and 126 are each sized to support half of the battery module array of battery string 134 and thus, each support rack 124 and 126 supports a 2x4 array of battery modules 140. Again, those of skill in the art will appreciate that that the battery strings may comprise more or fewer battery modules depending on the ESS power requirements and the size of the cabinet 102.

[0053] Turning now to Figures 9 to 14, one of the battery modules 140 is better illustrated. As can be seen in Figures 9 and 10, the battery module 140 comprises an outer casing 142 (shown as being transparent for ease of illustration) that houses a Lithium-ion cell array 143. The outer casing 142 in this embodiment is generally rectangular in plan and includes a removeable top wall 144, a bottom wall 146, opposed side walls 148, a rear wall 150, and a front wall 152. A pair of laterally spaced handles 154 are provided on each casing side wall 148 to facilitate carrying of the battery module 140 thereby to assist installation and removal of the battery module 140. The front wall 152 has a pair of laterally spaced vent holes 154 provided therein. A connector 156 that acts as the charging point for the battery module 140 is also provided on the front wall 152. A bumper 157 extends between the inside surface of the front wall 152 and the Lithium-ion cell array 143 and is retained by a bolt 157a. The rear wall 150 has a pair of openings therein through which male pins 158 of the battery module 140 pass. Although not shown, the connector pins 158 engage a conductive rail that is electrically coupled to conductive rails associated with other battery modules via connectors thereby toelectrically connect the battery module 140 to one or more other battery modules in series.

[0054] Figures 11 to 14 better illustrate the interior of the casing 142 and in particular, the Lithium-ion cell array 143. As can be seen, the Lithium-ion cell array 143 comprises a plurality of Lithium-ion cells 160. Although not shown and as will be appreciated by those of skill in the art, the Lithium-ion cells 160 are arranged in groups with the Lithium-ion cells of each group being electrically connected in parallel. The groups of Lithium-ion cells of the battery module 140 are electrically connected in series via electrical connectors 162 of an interconnect board 164 overlying the Lithium-ion cells 160.

[0055] Each battery module 140 further comprises sensors for monitoring conditions of the battery module 140 and that form part of an ESS suppression system as will be described. In this embodiment, the battery module sensors monitor temperature and voltage of the battery module 140.

[0056] In particular, in order to monitor temperature, the interconnect board 164 has a plurality of thermistors 170 mounted thereon. In this example, six (6) thermistors 170 are mounted on the interconnect board 164 at spaced locations with the probe side of each thermistor 170 being positioned between groups of Lithium-ion cells 160. In order to monitor voltage, the interconnect board 164 has a plurality of voltage sensors 172 mounted thereon. In particular, each group of Lithium-ion cells 160 as well as the positive and negative terminals of the battery module 140 have a voltage sensor 172 electrically connected thereto. A pair of connectors 174 is provided on the interconnect board 164 near the front wall 150 of the casing 142 to facilitate connection to a battery management system (BMS) 200 (see Figure 16) allowing the output of the thermistors 170 and voltage sensors 172 and hence, the temperature and voltage of the battery module 140 to be monitored. If desired, the interconnect board 164 can accommodate other sensors to allow other battery module parameters such as current, state of charge, cell capacity, efficiency etc. to be monitored by the BMS 200.

[0057] Those of skill in the art will appreciate that, although not shown for ease of illustration, the ESS 100 comprises a high voltage panel that is connected to an electrical grid via main connections. If the electrical grid is alternating current (AC), the high voltage panel comprises an AC to DC (direct current) converter and a step-down transformer allowing charging input power to be provided to the battery strings. TheESS 100 also comprises DC outputs that provide power to one or more electric vehicle (EV) charging stations.

[0058] As mentioned above, the ESS suppression system comprises temperature and voltage sensors in the battery modules 140 to monitor ESS conditions at the battery module level. In addition, the ESS suppression system comprises a plurality of other sensors positioned throughout the cabinet 102 to monitor a variety of ESS conditions at a cabinet level. In this embodiment, at the cabinet level the ESS suppression system monitors temperature and humidity within the cabinet 102, and for the presence of smoke and gas within the cabinet 102. In this particular example, two (2) gas sensors 210 and 212, two (2) smoke detectors 214, two (2) temperature sensors 216, and two (2) humidity sensors 218 are provided in the cabinet 102 (see Figure 5). Those of skill in the art will however appreciate that more or fewer sensors may be employed.

[0059] In this embodiment, the two gas sensors comprise a hydrogen (H2) sensor 210 configured to sense the concentration of hydrogen within the cabinet 102 and a hydrocarbon sensor 212 configured to sense the concentration of hydrocarbon gasses such as carbon monoxide, carbon dioxide, methane etc. within the cabinet 102. The H2 sensor 210 in this example is generally centrally positioned within the cabinet 102 and is mounted to the top wall 104 of the cabinet 102. The H2 sensor 210 can of course be positioned at other locations within the cabinet 102 although it is preferred that the H2 sensor 210 is mounted near the top wall 104 to ensure prompt sensing of hydrogen within the cabinet 102. The hydrocarbon sensor 212 in this example is also generally centrally positioned within the cabinet 102 and is mounted to the bottom wall 106 of the cabinet 102. The hydrocarbon sensor 212 can also of course be positioned at other locations within the cabinet 102 although it is preferred that the hydrocarbon sensor 212 is mounted near the bottom wall 106 of the cabinet 102 to ensure prompt sensing of hydrocarbon gases within the cabinet 102.

[0060] In this embodiment, the two smoke detectors 214 are mounted to the top wall 104 of the cabinet 102 adjacent the opposite sides 108 of the cabinet 102. The smoke detectors 214 can of course be positioned at other locations within the cabinet 102 although it is preferred that the smoke detectors 214 are mounted near the top wall 104 to ensure prompt sensing of smoke within the cabinet 102.

[0061] In this embodiment, the two temperature sensors 216 are mounted to the top wall 104 of the cabinet 102 adjacent diagonally opposite corners of the cabinet 102. The humidity sensors 218 are positioned adjacent the temperature sensors 216. Thehumidity sensors 218 may be standalone sensors or may be embedded within the temperature sensors 216. In this embodiment, the humidity sensors 218 are embedded within the temperature sensors 216. The temperature and humidity sensors can of course be positioned at other locations within the cabinet 102 although it is preferred that the temperature sensors 216 are mounted near the top wall 104.

[0062] In addition to the battery module level and cabinet level sensors, the ESS suppression system comprises a pressurized suppression agent tank 230 that contains a suppression agent used to mitigate battery module fires and inhibit thermal runaway. In this embodiment, the suppression agent is Fike Blue™ manufactured by the Fike Corporation of Blue Springs, Missouri or NovecTM 1230 manufactured by the 3M Corporation of Maplewood, Minnesota. Of course, those of skill in the art will appreciate that other suitable suppression agents may be employed.

[0063] A conduit network is connected to the suppression agent tank 230 via a solenoid valved inlet 232. The solenoid valved inlet 232 remains in a closed condition when powered and automatically opens when unpowered. The conduit network in this embodiment comprises a main delivery line 234 that extends throughout the cabinet 102 to each of the battery strings and branch lines 236 extending upwardly from the main delivery line 234. Each branch line 236 is associated with a respective column of battery modules 140. Dry sprinkler heads 238 extend generally horizontally from each branch line 236 at vertically spaced locations and pass into associated battery modules 140 via the vent holes 154 in the front walls 152 of the casings 142. Mounting brackets 240 fixed to the support racks support the dry sprinkler heads 238. In this embodiment, the main delivery line 234 and branch lines 236 are formed of stainless steel although one of ordinary skill in the art will appreciate that other suitable tubing material may be employed.

[0064] Figure 16 is a general electrical schematic showing the layout of the ESS suppression system. As illustrated, the BMS 200 is connected to and monitors the thermistors 170 and voltage sensors 172. The BMS 200 is also connected to a programmable logic controller (PLC) 250 or other suitable logic processing or computing device. The PLC 250 is connected to and monitors the smoke detectors 214, temperature sensors 216, humidity sensors 218, and gas sensors 210 and 212 and is connected to a dispatch module 252, an estop system 254, alarm and strobe lights 256 on the cabinet 102, the latch mechanisms 118, and the solenoid valved inlet 232 of the conduit network.

[0065] In general, by virtue of the various sensors employed, namely the thermistors 170, voltage sensors 172, gas sensors 210 and 212, smoke detectors 214, temperature sensors 216, and humidity sensors 218, the ESS suppression system is able to monitor a plurality of ESS conditions at both cabinet and battery module levels substantially simultaneously. In the event of a potential or actual ESS failure event, at least one and typically multiple sensors will trigger. This provides the ESS with multiple levels of failure redundancy and allows the ESS suppression system to take preventative actions in a predictive manner to inhibit the occurrence of a thermal runway event. When a trigger event happens signifying a potential or actual ESS failure event, depending on the activated sensor(s), the ESS suppression system conditions the ESS 100 based on the potential severity of the ESS failure event.

[0066] For example, if one or more thermistors 170, voltage sensors 172, temperature sensors 216, and humidity sensors 218 are triggered due to a potential ESS failure event in response to sensed temperatures, voltages, and / or humidity levels reaching an initial threshold value, the ESS suppression system isolates the ESS 100 thereby shutting down its input and output power. In this state, the thermistors 170, voltage sensors 172, and temperature sensors 216 are continued to be monitored to determine if the potential ESS failure event escalates or whether the potential ESS failure event stabilizes and the monitored conditions return to normal levels.

[0067] If the temperature sensed by any activated thermistor / temperature sensor and if the voltage sensed by any activated voltage sensor stabilize before reaching an upper threshold value, no further operational constraints are placed on the ESS 100.

[0068] If the temperature sensed by any activated thermistor / temperature sensor and / or if the voltage sensed by any activated voltage sensor reaches the upper threshold value, the ESS suppression system takes preventative actions to prepare the ESS 100 for a potential fire event. Similarly, if one or more of the gas sensors 210 and 212 or both smoke detectors 214 are triggered, the ESS suppression system takes preventative actions to prepare the ESS 100 for a potential fire event. The preventative actions include priming the delivery and branch lines 234 and 236 of the conduit network with suppression agent so that if a dry sprinkler head 238 is triggered due to a battery module 140 reaching a critical threshold temperature, suppression agent can be quickly and effectively delivered to the battery module 140 quenching any battery module fire before thermal runaway occurs. Further specifics of the ESS suppression system strategy will now be described with reference to Figure 17.

[0069] In this embodiment, if any of the thermistors 170 senses a temperature that exceeds an initial threshold temperature generally in the range of from about 45°C to about 80°C, the existence of a potential ESS failure event is determined. In this embodiment, the initial threshold temperature is 45°C. In this case, the BMS 200 responds to the thermistor 170 and conditions the ESS 100 to an initial shutdown mode 300.

[0070] In the initial shutdown mode, the BMS 200 signals a main BMS (not shown) causing the main BMS to shutdown the input to and output power from the ESS 100. Control power drawn from the battery strings of the ESS 100 is maintained. During the initial shutdown mode, the thermistors 170 are continually monitored to determine if a thermistor 170 senses a temperature that has reached an upper threshold temperature 302 above the initial threshold temperature. In this embodiment, the upper threshold temperature is at least 80°C.

[0071] During the initial shutdown mode, if the temperature sensed by the thermistors 170 stabilizes and remains below the upper threshold temperature, the BMS 200 does not escalate the mode setting of the ESS 100. When the temperature sensed by the thermistors 170 drops below the initial threshold temperature, the BMS 200 conditions the ESS 100 to reset 304 in an attempt to return the ESS 100 to normal operation 306.

[0072] When in the initial shutdown mode, if a thermistor 170 senses a temperature that exceeds the upper threshold temperature, the BMS 200 conditions the ESS 100 to an alarm mode signifying a potential fire event and signals the PLC 250. In response to the BMS signal, the PLC 250 takes a number of preventative actions to prepare the ESS 100 for the potential of fire event.

[0073] In particular, the PLC 250 activates the dispatch module 252. Upon activation of the dispatch module 252, one or more automatic calls are made by the ESS 100 to advise of the alarm mode. In this example, automatic calls are made to the local fire department 310 and to one or more designated individuals (“key personnel”), such as personnel of eCamion of Toronto, Ontario, assignee of the subject application 312. Automatic calls to the key personnel can be made in a sequenced priority order or the automatic calls to the key personnel can be made in parallel or randomly.

[0074] In addition to activating the dispatch module 252, the PLC 250 activates the strobe lights and / or alarm 256 mounted on the cabinet 102 to visually and audibly warn of the alarm mode and activates the estop system 254. Activation of the estop system254 causes each of the battery modules 140 to electrically isolate the Lithium-ion cells 160 therein thereby to completely shut down the ESS 100. The PLC 250 also signals the latch mechanisms 118 causing them to release the vent panels 114. As a result, the vent panels 114 swing outwardly under the bias of the spring mechanisms 116 thereby to open the vents in the side panels 108a. Furthermore, the PLC 250 disconnects the power supply to the solenoid valved inlet 232 of the conduit network causing it to open resulting in the delivery and branch lines 234 and 236 of the conduit network being primed with suppression agent from the tank 230.

[0075] At this stage, if the temperature within any of the battery modules 140 reaches a critical threshold temperature signifying a fire event, the seal on the dry sprinkler head 238 within that battery module 140 automatically breaks causing the dry sprinkler head 238 to trigger resulting in the suppression agent being dispersed within the battery module 140 thereby to extinguish any fire within the battery module 140 and inhibit thermal runaway. In this embodiment, the critical threshold temperature is at least 100°C. Those of skill in the art will appreciate that the critical threshold temperature may vary depending on the design of the dry sprinkler head 238 and the temperature at which its seal is configured to break. As will also be appreciated, since the delivery and branch lines of the conduit network are all primed with suppression agent in advance of any sprinkler head 238 triggering, once a sprinkler head is activated, suppression agent is dispersed substantially immediately into the battery module 140 allowing the total energy within the battery module to be dissipated without the suppression agent undergoing a temperature rise of more than 30°C.

[0076] In this embodiment, if any of the voltage sensors 172 senses a battery module voltage that reaches a threshold overvoltage generally in the range of 4.2V to 4.3V, the existence of a potential ESS failure event is also determined. In this embodiment, the threshold overvoltage is 4.2V. In this case, the BMS 200 responds to the voltage sensor 172 and conditions the ESS 100 to the initial shutdown mode 300. During the initial shutdown mode, the voltages of the battery modules 140 are continually monitored to determine whether a voltage sensor 172 senses a battery module voltage that exceeds an upper threshold overvoltage greater than or equal to 4.3V.

[0077] During the initial shutdown mode, if the voltages of the battery modules 140 sensed by the voltage sensors 172 stabilize and remain below the upper threshold overvoltage, the BMS 200 does not escalate the mode setting of the ESS 100. Whenthe voltages sensed by the voltage sensors drop below the initial threshold voltage, the BMS 200 conditions the ESS 100 to reset 304 in an attempt to return the ESS 100 to normal operation 306.

[0078] When in the initial shutdown mode, if a voltage sensor 172 senses a battery module voltage that exceeds the upper threshold overvoltage, the BMS 200 conditions the ESS 100 to the alarm mode. In response, the PLC 250 takes the preventative actions described above to prepare the ESS 100 for the potential fire event.

[0079] When either temperature sensor 216 senses a cabinet temperature reaching the initial threshold temperature, the PLC 250 responds and conditions the ESS 100 to the initial shutdown mode. If the temperature sensed by the temperature sensors 216 stabilizes and remains below the upper threshold temperature, the PLC 250 does not escalate the mode setting of the ESS 100. When the temperature sensed by the temperature sensors 216 drops below the initial threshold temperature, the PLC 250 conditions the ESS 100 to reset in an attempt to return the ESS to normal operation.

[0080] When in the initial shutdown mode, if either temperature sensor 216 senses a temperature that exceeds the upper threshold temperature, the PLC 250 conditions the ESS 100 to the alarm mode and the PLC 250 takes the preventative actions described above.

[0081] When either of the humidity sensors 218 senses a 90% or greater relative humidity level within the cabinet 102, the PLC 250 responds and conditions the ESS 100 to the initial shutdown mode 300. The voltages of the battery modules 140 are monitored to determine whether the voltage at any battery module 140 exceeds the upper threshold overvoltage.

[0082] In this case, if the voltages at the battery modules 140 sensed by the voltage sensors 172 stabilize and remain below the upper threshold overvoltage, the BMS 200 does not escalate the mode setting of the ESS 100. When the voltages sensed by the voltage sensors 172 drop below the initial threshold voltage, the BMS 200 conditions the ESS 100 to reset 304 in an attempt to return the ESS 100 to normal operation 306.

[0083] If, however, a voltage sensor 172 senses a battery module voltage that exceeds the upper threshold overvoltage, the BMS 200 conditions the ESS 100 to the alarm mode. In response, the PLC 250 takes the preventative actions described above to prepare the ESS 100 for the potential fire event.

[0084] The gas sensors, which sense the presence of hydrogen and / or hydrocarbons in the cabinet 102, are continually monitored by the PLC 250 to ensurethey are operating in an “on” state 330. If both gas sensors 210 and 212 are not operating in an “on” state, the PLC 250 sends an alert notice to the key personnel 322, and the ESS 100 is reset 304 in attempt to return the ESS 100 to normal operation 306.

[0085] If either of the gas sensors 210, 212 is activated, the PLC 250 immediately conditions the ESS 100 to the alarm mode and takes the preventative actions described above to prepare the ESS 100 for the potential fire event.

[0086] Likewise, if both of the smoke detectors 214 are activated, the PLC 250 immediately conditions the ESS 100 to the alarm mode and takes the preventative actions described above to prepare the ESS 100 for the potential fire event.

[0087] As will be appreciated, the ESS suppression system progresses through a series of stages depending on sensed ESS conditions allowing proactive safety steps to be taken as sensed ESS conditions escalate. This predictive operation allows suitable steps to be taken at various sensed ESS condition levels including runaway suppression thereby to ensure safe operation of the ESS 100.

[0088] Although embodiments have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the scope of the appended claims.

Claims

What is claimed is:

1. An energy storage system (ESS) comprising: a cabinet; at least one battery string within the cabinet, the at least one battery string comprising a plurality of battery modules; and a suppression system within the cabinet configured to monitor a plurality of ESS conditions and to condition the ESS in a staged manner as monitored ESS conditions escalate as a result of a potential ESS failure event.

2. The ESS of claim 1 , wherein the suppression system is configured to: monitor ESS conditions at a cabinet level; monitor ESS conditions at a battery module level; or monitor ESS conditions at both cabinet and battery module levels.

3. The ESS of claim 2, wherein the ESS conditions monitored at the cabinet level comprise two or more of temperature, humidity, presence of smoke, presence of hydrogen, and presence of hydrocarbons.

4. The ESS of claim 2, wherein the ESS conditions monitored at the cabinet level comprise temperature, humidity, presence of smoke, presence of hydrogen, and presence of hydrocarbons.

5. The ESS of any one of claims 2 to 4, wherein the ESS conditions monitored at the battery module level comprise temperature and voltage.

6. The ESS of any one of claims 1 to 5, wherein the suppression system is configured to condition the ESS to an initial shutdown mode in response to at least one of a sensed temperature, humidity, or voltage reaching an initial threshold value.

7. The ESS of claim 6, wherein the sensed temperature is at least one of a sensed ambient temperature within the cabinet reaching the initial threshold value and a sensed temperature within a battery module reaching the initial threshold value.

8. The ESS of claim 7, wherein the initial threshold value is in the range of from about 45°C to about 80°C.

9. The ESS of claim 7, wherein the sensed humidity is a sensed relative humidity within the cabinet reaching the initial threshold value.

10. The ESS of claim 9, wherein the initial threshold value is 90% relative humidity or greater.

11. The ESS of claim 7, wherein the sensed voltage is a voltage within a battery module reaching the initial threshold value.

12. The ESS of claim 11 , wherein the initial threshold value is in the range of 4.2V to 4.3V.

13. The ESS of claim 6, wherein in the initial shutdown mode input power to and output power from the ESS is terminated.

14. The ESS of claim 6, wherein the suppression system is conditioned to an alarm mode in response to at least one of the sensed temperature or sensed voltage reaching an upper threshold value above initial threshold value.

15. The ESS of claim 14, wherein the upper threshold value is a sensed temperature equal to or exceeding 80°C or a sensed voltage equal to or exceeding 4.3V.

16. The ESS of claim 14, wherein the suppression system is configured to initiate a plurality of preventative actions in the alarm mode.

17. The ESS of claim 16, wherein in the alarm mode the suppression system is configured to at least one of: prime a suppressant agent delivery system configured to deliver a suppressant agent to the battery modules; activate visual and / or audio alarms;automatically initiate calls to local fire department(s) and / or key personnel; and disable the battery modules.

18. The ESS of claim 16, wherein in the alarm mode the suppression system is configured to: prime a suppressant agent delivery system configured to deliver a suppressant agent to the battery modules; activate visual and / or audio alarms; automatically initiate calls to local fire department(s) and / or key personnel; and disable the battery modules.

19. The ESS of claim 18, further comprising the suppressant agent delivery system, wherein the suppressant agent delivery system comprises a conduit network connected to at least one pressurized suppression agent tank, the conduit network extending to each of the battery modules and comprising sprinkler heads extending into the battery modules.

20. The ESS of claim 19, wherein each sprinkler head is configured to automatically trigger to deliver suppression agent to an associated battery module when the temperature in the associated battery module reaches a critical threshold value.

21. A method of suppressing thermal runaway in an energy storage system (ESS) comprising at least one battery string have a plurality of battery modules and accommodated by a cabinet, the method comprising: monitoring, using sensors, a plurality of environmental conditions of the ESS; and in the event of a potential ESS failure event, take preventative actions in a predictive manner as monitored environmental conditions of the ESS signify escalation of the ESS failure event.

22. The method of claim 21 , wherein the monitoring comprises monitoring environmental conditions of the ESS at a battery module level and at a cabinet level.

23. The method of claim 22, wherein the monitoring at the battery module level comprises monitoring battery module temperature and voltage.

24. The method of claim 21 or 22, wherein the monitoring at the cabinet level comprises monitoring at least one of temperature, relative humidity, presence of gas, and presence of smoke within the cabinet.

25. The method of claim 21 or 22, wherein the monitoring comprises monitoring temperature, relative humidity, presence of gas, and presence of smoke within the housing.

26. The method of claim 24 or 25, wherein monitoring presence of gas within the housing comprises monitoring for the presence of hydrogen and / or hydrocarbons.

27. The method of any one of claims 21 to 26, wherein in the event of a potential ESS fire event, the method further comprises at least one of: priming a suppressant agent delivery system configured to deliver a suppressant agent to the battery modules; activating visual and / or audio alarms; automatically initiating calls to local fire department(s) and / or key personnel; and disabling the battery modules.

28. The method of any one of claims 21 to 26, wherein in the event of a potential ESS fire event, the method further comprises: priming a suppressant agent delivery system configured to deliver a suppressant agent to the battery modules; activating visual and / or audio alarms; automatically initiating calls to local fire department(s) and / or key personnel; and disabling the battery modules. event.

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