Patent Publication Number: US-2022223934-A1

Title: Ess including superabsorbent sheet

Description:
TECHNICAL FIELD 
     The present disclosure relates to an ESS (Energy Storage System) including a superabsorbent sheet, and more particularly, to an ESS including a superabsorbent sheet, which is adapted for effective cooling just with a relatively small amount of cooling water when an abnormal temperature rise occurs due to heating of a battery module. 
     The present application claims priority to Korean Patent Application No. 10-2020-0024461 filed on Feb. 27, 2020 in the Republic of Korea, the disclosures of which are incorporated herein by reference. 
     BACKGROUND ART 
     In an ESS including a plurality of battery cells, if an abnormality such as a short circuit occurs in some battery cells, the temperature of the battery cells continuously rises. As a result, if the temperature of the battery cells exceeds a critical temperature, a thermal runaway phenomenon occurs. If a thermal runaway phenomenon occurs in some battery cells, safety issues may arise. 
     If a flame is generated in a battery module including the battery cell due to the thermal runaway phenomenon occurring in some battery cells, the temperature of neighboring battery modules rises rapidly, which may propagate the thermal runaway phenomenon to the entire ESS within a short time. 
     As a result, if the thermal runaway phenomenon occurring in some battery cells is not quickly handled, the damage caused by the thermal runaway may be expanded to the battery module, which is a battery unit with a larger capacity than the battery cell, or to a sub ESS including a plurality of battery modules. If the expansion of damage caused by the thermal runaway is not appropriately handled, this may lead to disasters such as ignition and explosion of the battery module and the sub ESS, which may cause not only property damage but also safety issues. 
     Therefore, when flame occurs due to thermal runaway in some battery cells inside the battery module, it is important to block the expansion of the flame generation range inside the sub ESS. In addition, if the flame is already expanded entirely inside one sub ESS, it is important to increase the efficiency of fire extinguishing and cooling so that the flame does not move to sub ESSs adjacent to the sub ESS where the flame is generated. 
     DISCLOSURE 
     Technical Problem 
     The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to performing proper extinguishing and cooling when the flame is expanded entirely inside one sub ESS, so that the flame does not move to sub ESSs adjacent to the sub ESS where the flame is generated. 
     In addition, the present disclosure is directed to performing proper extinguishing and cooling so that flame is not propagated to neighboring battery modules, when the flame is generated in some battery modules included in one sub ESS. 
     However, the technical object to be solved by the present disclosure is not limited to the above, and other objects not mentioned herein will be clearly understood by those skilled in the art from the following disclosure. 
     Technical Solution 
     In one aspect of the present disclosure, there is provided an ESS (Energy Storage System), comprising: a sub ESS stack including a plurality of sub ESSs, each having a plurality of battery modules and a battery rack for accommodating the plurality of battery modules; an ESS housing configured to accommodate the plurality of sub ESSs; a sensor installed in the ESS housing to sense at least one of temperature and smoke inside the ESS housing; a first blocking sheet interposed between the sub ESSs adjacent to each other; a fire extinguishing device configured to supply a fire extinguishing agent into the ESS housing; and a cooling device configured to supply a cooling water to the first blocking sheet. 
     The first blocking sheet may be a superabsorbent sheet. 
     The first blocking sheet may include a superabsorbent fiber capable of absorbing and containing 20 g to 200 g of cooling water per 1 g. 
     The battery module may include a cell stack formed by stacking a plurality of battery cells; and a module housing configured to accommodate the cell stack. 
     The plurality of battery modules may be stacked up and down inside the battery rack. 
     The ESS may further comprise at least one second blocking sheet interposed between the battery modules adjacent to each other along an upper and lower direction inside the battery rack. 
     The second blocking sheet may be disposed to penetrate through the battery rack and traverse from one side of the sub ESS stack in a stacking direction to the other side thereof. 
     The first blocking sheet may have a first coupling slit, and the second blocking sheet may be inserted into the first coupling slit and coupled to the first blocking sheet. 
     The second blocking sheet may have a second coupling slit, and the first blocking sheet may be inserted into the second coupling slit and coupled to the second blocking sheet. 
     The second blocking sheet may be a superabsorbent sheet. 
     The second blocking sheet may include a superabsorbent fiber capable of absorbing and containing 20 g to 200 g of cooling water per 1 g. 
     The superabsorbent fiber may include a superabsorbent resin containing at least one of a starch-based material, a cellulose-based material and a synthetic polymer-based material. 
     The ESS may further comprise a control device configured to control the operation of the fire extinguishing device and the cooling device by referring to at least one of the information about temperature and the information about smoke generation, sensed by the sensor. 
     Advantageous Effects 
     According to an embodiment of the present disclosure, it is possible to perform proper extinguishing and cooling when the flame is expanded entirely inside one sub ESS, so that the flame does not move to sub ESSs adjacent to the sub ESS where the flame is generated. 
     In addition, according to an embodiment of the present disclosure, it is possible to perform proper extinguishing and cooling so that flame is not propagated to neighboring battery modules, when the flame is generated in some battery modules included in one sub ESS. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The accompanying drawings illustrate a preferred embodiment of the present disclosure and together with the foregoing disclosure, serve to provide further understanding of the technical features of the present disclosure, and thus, the present disclosure is not construed as being limited to the drawing. 
         FIG. 1  is a diagram showing an ESS according to an embodiment of the present disclosure. 
         FIG. 2  is a diagram showing a sub ESS and a first blocking sheet, employed at the ESS according to an embodiment of the present disclosure. 
         FIG. 3  is a diagram showing a battery module according to the present disclosure. 
         FIG. 4  is a block diagram showing a control logic for automation of fire extinguishing and cooling of the ESS according to an embodiment of the present disclosure. 
         FIG. 5  is a diagram showing an ESS according to another embodiment of the present disclosure. 
         FIG. 6  is a diagram showing a sub ESS, a first blocking sheet and a second blocking sheet, employed at the ESS according to another embodiment of the present disclosure. 
         FIGS. 7 and 8  are diagrams showing a coupled configuration of the first blocking sheet and the second blocking sheet, employed at the ESS according to another embodiment of the present disclosure. 
     
    
    
     BEST MODE 
     Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Prior to the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the disclosure, so it should be understood that other equivalents and modifications could be made thereto without departing from the scope of the disclosure. 
     An ESS (Energy Storage System) according to an embodiment of the present disclosure will be described with reference to  FIGS. 1 to 4 . 
     First, referring to  FIGS. 1 and 2 , the ESS according to an embodiment of the present disclosure includes a plurality of sub ESSs  100 , an ESS housing  200 , a first blocking sheet  300 , a fire extinguishing device  400 , a cooling device  500  and a sensor  600 . 
     The sub ESS  100  includes a battery rack  110  and a plurality of battery modules  120  accommodated in the battery rack  110 . The battery rack  110  has open front and rear surfaces. The plurality of sub ESSs  100  are arranged side by side in a left and right directions so that the side surfaces of the battery racks  110  face each other, thereby forming one sub ESS stack. 
     Referring to  FIG. 2 , the plurality of battery modules  120  are stacked in an upper and lower direction inside the battery rack  110  to form one module stack. 
     Referring to  FIG. 3 , the battery module  120  includes a plurality of battery cells  121 , a bus bar frame  122 , a module housing  123 , an air inlet  124  and an air outlet  125 . 
     The battery cell  121  is provided in plural, and the plurality of battery cells  121  are stacked to form one cell stack. As the battery cell  121 , a pouch-type battery cell may be applied, as an example. The battery cell  121  includes a pair of electrode leads  121   a,  which are respectively drawn to both sides in a longitudinal direction. 
     The bus bar frame  122  is provided in a pair, and the pair of bus bar frames  122  cover one side and the other side of the cell stack in a width direction, respectively. The electrode lead  121   a  of the battery cell  121  is drawn out through a slit formed at the bus bar frame  122  and may be bent and electrically connected by the bus bar frame  122 . 
     The module housing  123  has a substantially rectangular parallelepiped shape and accommodates the cell stack therein. The air inlet  124  and the air outlet  125  are formed at one longitudinal side and the other longitudinal side of the module housing  123 . 
     The air inlet  124  is formed at one side of the cell stack in the stacking direction, namely at one longitudinal side of the battery module  120 , and is formed in the form of a hole through the module housing  123 . The air outlet  125  is formed at the other side of the cell stack in the stacking direction, namely at the other longitudinal side of the battery module  120 , and is formed in the form of a hole through the module housing  123 . 
     The air inlet  124  and the air outlet  125  are located at opposite sides diagonally along the longitudinal direction of the battery module  120 . 
     Meanwhile, an empty space is formed between the bus bar frame  122  and the module housing  123 . That is, an empty space is formed between one of six outer surfaces of the module housing  123 , which faces one longitudinal side and the other longitudinal side of the battery cell  121 , and the bus bar frame  122  so that air for cooling the battery cell  121  may flow therethrough. The empty space is formed at both sides of the battery module  120  in the width direction. 
     The air inlet  124  is formed at a position corresponding to the empty space formed at one side of the battery module  120  in the width direction, and the air outlet  125  is formed at a position corresponding to the empty space formed at the other side of the battery module  120  in the width direction. 
     In the battery module  120 , the air introduced into the battery module  120  through the air inlet  124  cools the battery cell  121  while moving from the empty space formed at one side of the battery module  120  in the width direction to the empty space formed at the other side of the battery module  120  in the width direction, and then is discharged through the air outlet  125 . That is, the battery module  120  corresponds to an air-cooled battery module. 
     Since the battery module  120  applied to the present disclosure has an air-cooled structure as described above, flame is likely to be ejected out of the module housing  123 . That is, if an abnormality occurs in some of the battery cells  121  included in the battery module  120  so that the temperature inside the battery cells  121  rises and thus gas is leaked out by venting, a flame may be generated. The generated flame may be ejected out of the module housing  123  through the air inlet  124  and the air outlet  125 , which are formed for air cooling. 
     Referring to  FIGS. 1 and 2 , when an abnormal temperature rise occurs and thus a flame is generated in some battery module  120  as described above, the first blocking sheet  300  prevents the flame from moving to sub ESSs  100  adjacent to the sub ESS  100  that includes the battery module  120  with the above problem. 
     To perform the above function, the first blocking sheet  300  is interposed between the sub ESSs  100  adjacent to each other. The first blocking sheet  300  is a super absorbent sheet. That is, the first blocking sheet  300  includes a super absorbent fiber, and the superabsorbent fiber may absorb and contain approximately 20 g to 200 g of cooling water per 1 g. The superabsorbent fiber may include, for example, a super absorbent resin (or a super absorbent polymer) including at least one of a starch-based material, a cellulose-based material or a synthetic polymer-based material. The superabsorbent fiber is obtained by spinning a superabsorbent resin into a net form. 
     If a cooling water supplied from the cooling device  500 , the first blocking sheet  300  may quickly absorb the cooling water, and the first blocking sheet  300  absorbing the cooling water may prevent the abnormal temperature rise and/or the flame occurring in some sub ESS  100  from being propagated to neighboring sub ESSs  100 . 
     The first blocking sheet  300  preferably has an area corresponding to the side surface of the sub ESS  100  in order to minimize the amount of used cooling water and maximize the cooling effect and the flame expansion blocking effect. However, a longitudinal end of the first blocking sheet  300  may be exposed to the top of the sub ESS stack in order to quickly absorb the cooling water supplied from the cooling device  500 . 
     Referring to  FIG. 1 , the fire extinguishing device  400  sprays the fire extinguishing agent into the ESS housing  200  when the internal temperature of the ESS housing  200  rises above a reference value and/or smoke is sensed, thereby preventing the occurrence of fire in advance or extinguishing the fire that has already occurred. As the fire extinguishing agent, for example, a clean fire extinguishing agent in the form of a gas such as Novec  1230  may be applied, and also, nitrogen and solid aerosol may be applied. 
     The fire extinguishing device  400  includes a fire extinguishing agent tank  410  installed at an outer side of the ESS housing  200  to store the fire extinguishing agent and an extinguishing agent injection tube  420  having one side connected to the fire extinguishing agent tank  410  and the other side penetrating the ESS housing  200 . 
     If the internal temperature of the ESS housing  200  rises above the reference value and/or smoke is sensed due to fire, the cooling device  500  sprays the cooling water into the ESS housing  200  to prevent the occurrence of fire in advance or extinguish the fire that has already occurred. 
     More specifically, the cooling device  500  sprays the cooling water directly onto the first blocking sheet  300 . The cooling device  500  includes a cooling water supply tube  520  connected to the cooling water tank  510  that stores the cooling water, and a plurality of cooling water injection tubes  530  branched at an end of the cooling water supply tube  520  and disposed at a position corresponding to each first blocking sheet  300 . 
     Even though the drawing of the present disclosure illustrate only the case where the cooling water supply tube  520  is located at the outer side of the ESS housing  200  and the cooling water injection tube  530  passes through the ESS housing  200 , the present disclosure is not limited thereto. That is, it is also possible that the cooling water supply tube  520  passes through the ESS housing  200  and the cooling water injection tube  530  is branched from the cooling water supply tube  520  inside the ESS housing  200 . 
     Referring to  FIG. 1 , the sensor  600  is installed inside the ESS housing  200  to sense at least one of temperature and smoke generation inside the ESS housing. That is, the sensor  600  corresponds to a temperature sensor and/or a smoke sensor. 
     Although not shown in the drawings, the information sensed by the sensor  600  and/or an alarm according to the sensed information may be displayed through a user interface disposed outside the module housing  200 . If a user judges through the sensed information and/or alarm that there is a risk of fire or that a fire has occurred, the user may operate the fire extinguishing device  400  and the cooling device  500  to extinguish or prevent the fire inside the ESS. 
     Meanwhile, referring to  FIG. 4 , the ESS according to an embodiment of the present disclosure may further include a control device  700 , in addition to the above-described components. The control device  700  controls the operation of the fire extinguishing device  400  and the cooling device  500  by referring to the information about temperature and/or the information about smoke generation sensed by the sensor  600 . 
     That is, the control device  700  is an element applied to achieve automation of fire extinguishing and/or cooling by allowing the fire extinguishing device  400  and the cooling device  500  to operate without user manipulation when certain conditions are satisfied. The reference temperatures for operating the fire extinguishing device  400  and the cooling device  500  may be determined in consideration of the number of the sub ESSs  100 , the number of battery modules  120  included in the sub ESS  100 , the number of battery cells  121  included in the battery module  120 , the capacity of the battery cell  121 , and the like. 
     Next, an ESS according to another embodiment of the present disclosure will be described with reference to  FIGS. 5 to 8 . 
     The ESS according to another embodiment of the present disclosure is different from the ESS of the former embodiment only in that a second blocking sheet  310  is additionally applied, and other components are substantially the same. Accordingly, in describing the ESS according to another embodiment of the present disclosure, the second blocking sheet  310  will be described in detail, and other components already described in the former embodiment will not be described in detail again. 
     Referring to  FIGS. 5 and 6 , the second blocking sheet  310  is interposed between the battery modules  120  adjacent to each other along the upper and lower direction inside the battery rack  110 . The second blocking sheet  310  is disposed to penetrate the side surface of the battery rack  110  and traverse from one side of the sub ESS  100  in the stacking direction to the other side thereof. 
     One second blocking sheet  310  or a plurality of second blocking sheets  310  may be provided. If only one second blocking sheet  310  is provided, it is efficient that the second blocking sheet  310  is disposed at the center of the battery rack  110  along the stacking direction of the battery module  120 . The material of the second blocking sheet  310  is the same as the first blocking sheet  300  described above. 
     Referring to  FIG. 7 , the first blocking sheet  300  and the second blocking sheet  310  may be coupled to each other by forming a first coupling slit  300   a  at each first blocking sheet  300  and inserting the second blocking sheet  310  into the first coupling slit  300   a.  In this case, the position and shape of the first coupling slit  300   a  formed at the first blocking sheet  300  correspond to a slit (not shown) formed at the side surface of the battery rack  110  for the passage of the second blocking sheet  310 . 
     Referring to  FIG. 8 , the first blocking sheet  300  and the second blocking sheet  310  may be coupled to each other by forming a second coupling slit  310   a  at the second blocking sheet  310  in a number corresponding to the first blocking sheets  300  and inserting the first blocking sheet  300  into the second coupling slit  310   a,  unlike that shown in  FIG. 7 . 
     As the first blocking sheet  300  and the second blocking sheet  310  are connected to each other in this way, the first blocking sheet  300  may absorb the cooling water supplied from the top of the first blocking sheet  300 , and the second blocking sheet  310  may absorb a part of the absorbed cooling water again, thereby preventing the thermal runaway phenomenon from expanding along the stacking direction of the sub ESS stacks and the stacking direction of the battery modules  120 . 
     The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description.