Energy storage apparatus and method for monitoring energy storage device

Abstract

To improve the quality of monitoring of a plurality of power storage elements and the accuracy of abnormality sign detection.SOLUTION: The power storage device 10 includes a plurality of power storage elements 30, a temperature adjusting member 40 that comes into contact with the plurality of power storage elements 30 to adjust the temperature of the power storage elements 30, and a thermal image camera 50. The thermal imaging camera captures a thermal image of the temperature adjusting member 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for detecting abnormalities or signs of abnormalities in an energy storage element. [Background technology]

[0002] Patent Document 1 discloses a technique for extracting high-temperature areas from an inspection target area of ​​a solar panel using an infrared camera. Patent Document 2 discloses a technique for predicting power conditioner failures using machine learning. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-104003 [Patent Document 2] Patent No. 7246803 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, a large number of energy storage elements have been used in mobile vehicles such as electric vehicles and stationary energy storage systems such as power storage stations. In many cases, the temperature of the energy storage elements is measured using a contact-type temperature sensor such as a thermistor.

[0005] Due to cost and space constraints, it is difficult to install contact temperature sensors on all storage elements. Therefore, conventionally, the temperature of only representative points among all storage elements is measured by contact temperature sensors. The conventional configuration in which the temperature is measured only at representative points with contact temperature sensors leaves room for improvement in terms of the quality of monitoring and the accuracy of anomaly detection.

[0006] An object of one embodiment of the present invention is to improve the quality of monitoring a plurality of power storage elements and the accuracy of detecting a sign of abnormality. [Means for solving the problem]

[0007] The power storage device includes a plurality of power storage elements, a temperature adjusting member that contacts the plurality of power storage elements to adjust the temperature of the power storage elements, and a thermal imaging camera that captures a thermal image of the temperature adjusting member. [Effects of the Invention]

[0008] The present invention can improve the quality of monitoring a plurality of storage elements and the accuracy of detecting signs of abnormality. [Brief explanation of the drawings]

[0009] [Figure 1] Side view of the power storage device [Figure 2] Plan view of the power storage device [Figure 3] Perspective view of the energy storage element [Figure 4] Diagram showing the shape of the cooling pipe [Figure 5] Diagram showing the internal structure of the battery panel [Figure 6A] Thermal image of the front end of the cooling pipe [Figure 6B] Thermal image of the front end of the cooling pipe [Figure 7] Energy storage system block diagram [Figure 8] Power generation system block diagram [Figure 9] Side view of the power storage device [Figure 10] Perspective view of a lead-acid battery [Figure 11] Perspective view of element block and energy storage module DETAILED DESCRIPTION OF THE INVENTION

[0010] An outline of the embodiment will be described below. (1) A power storage device includes a plurality of power storage elements, a temperature adjustment member that contacts the plurality of power storage elements to adjust the temperature of the power storage elements, and a thermal imaging camera. The thermal imaging camera captures a thermal image of the temperature adjustment member. The thermal image visualizes the surface temperature of an object.

[0011] According to the configuration (1) above, it is possible to detect a temperature change of the temperature adjustment member that is in contact with the plurality of energy storage elements from the thermal image of the thermal imaging camera. By detecting the temperature change of the temperature adjustment member, it is possible to detect, for example, a temperature change caused by an abnormality or a sign of an abnormality in one of the plurality of energy storage elements. As a result, it is possible to improve the quality of monitoring the energy storage elements and the accuracy of detecting signs of an abnormality.

[0012] (2) In the energy storage device described in (1) above, the plurality of energy storage elements may be arranged in a line along a long side or a short side of the temperature adjustment member with their bottom surfaces in contact with the temperature adjustment member. The temperature adjustment member may have an imaged portion that can be photographed by the thermal imaging camera at an end of the energy storage elements in the lined-up direction.

[0013] According to the configuration (2) above, when a temperature change occurs in any of the plurality of storage elements arranged in the long side direction (or short side direction) of the temperature adjustment member (for example, the storage element behind the foremost storage element), the temperature change appears in the thermal image as a temperature change in the imaged portion. Therefore, if only the imaged portion is imaged with the thermal imaging camera, it is possible to detect an abnormality or a sign of an abnormality in any of the plurality of storage elements arranged in the long side direction (or short side direction) of the temperature adjustment member.

[0014] (3) In the energy storage device described in (2), the temperature adjustment member may include a cooling plate on which the energy storage elements are placed, and a cooling pipe held inside the cooling plate and through which a liquid circulates. The imaged portion may be a part of the cooling pipe.

[0015] According to the configuration (3) above, if any of the multiple electric storage elements in contact with the temperature adjustment member becomes hot, heat is transferred from that electric storage element to the liquid inside via the cooling pipe. When the hot liquid circulates through the cooling pipe and moves to the imaged portion (part of the cooling pipe), the temperature of the imaged portion (part of the cooling pipe) rises, and a temperature change appears in the thermal image, making it possible to detect the temperature rise of the liquid. Therefore, if the thermal imaging camera captures only the imaged portion (part of the cooling pipe), it can detect an abnormality or a sign of an abnormality in any of the multiple electric storage elements in contact with the temperature adjustment member.

[0016] (4) The energy storage device according to any one of (1) to (3) above may further include a housing that houses a plurality of energy storage elements and a temperature adjusting member that contacts the plurality of energy storage elements to adjust the temperature of the energy storage elements. The thermal imaging camera may be installed inside the housing. If a thermal imaging camera is installed outside the housing, only the surface temperature of the housing can be obtained. However, if a thermal imaging camera is installed inside the housing, a thermal image of the object to be imaged can be captured.

[0017] The techniques described in (1) to (4) above can be applied to a method for monitoring an energy storage element.

[0018] <Embodiment> 1. Explanation of the structure of the energy storage device 1 is a side view of the power storage device 10, and FIG. 2 is a plan view of the power storage device 10. FIG. 3 is a perspective view of the power storage element. The power storage device 10 includes a power storage module 20 and a thermal imaging camera 50.

[0019] The energy storage module 20 includes a plurality of energy storage elements 30 and a temperature adjustment member 40. As shown in Fig. 3, the energy storage elements 30 are, for example, prismatic cells (specifically, lithium ion battery cells) having a hollow rectangular parallelepiped case 31, and have a top surface 31A, a bottom surface 31B, a short side surface 31C, and a long side surface 31D. The long side surface 31D is perpendicular to the short side surface 31C and has a larger area than the short side surface 31C.

[0020] An electrode assembly formed by laminating a positive electrode, a separator, and a negative electrode, and an electrolyte (electrolytic solution) are housed in case 31. Energy storage element 30 also has a pair of cell terminals 32, 33 with opposite polarities on top surface 31A.

[0021] As shown in Figures 1 and 2, the multiple storage elements 30 are arranged side by side in the long side direction of the temperature adjustment member 40 (X direction in Figures 1 and 2) with their long sides 31D facing each other and their bottom surfaces 31B in contact with the temperature adjustment member 40.

[0022] Pouch cells (laminate type cells) can be used instead of prismatic cells as energy storage elements 30. When pouch cells are used, the long sides of a plurality of pouch cells are also opposed to each other, and the energy storage elements 30 are arranged side by side in the long side direction (X direction) of temperature adjustment member 40 with bottom surfaces 31B in contact with temperature adjustment member 40.

[0023] The temperature adjustment member 40 is of a liquid-cooled type and includes a cooling frame 41 and cooling pipes 45. The cooling frame 41 is made of a metal material with high thermal conductivity, and is box-shaped with a top surface, a bottom surface, and four side surfaces.

[0024] 2, cooling frame 41 is rectangular in plan view with long sides 41A in the X direction and short sides 41B in the Y direction. As shown in FIG. 1, the upper surface of cooling frame 41 is a mounting surface for energy storage elements 30, and multiple energy storage elements 30 can be mounted on it while lined up in the X direction. A thermally conductive sheet 43 may be provided on the upper surface of cooling frame 41.

[0025] The cooling frame 41 supports cooling pipes 45 therein. The cooling pipes 45 are metal pipes with high thermal conductivity, and a liquid (cooling water or coolant liquid) is circulated inside the cooling pipes 45 by a driving device such as a pump.

[0026] The cooling pipes 45 extend in the X direction so as to intersect with the energy storage devices 30 arranged on the cooling frame 41. The shape of the cooling pipes 45 may be a square ring shape along the inner surface of the cooling frame 41 as shown in Fig. 2, or may be a U-shape as shown in Fig. 4.

[0027] 2, cell terminals of some of the energy storage elements 30 are omitted in order to show the shape of the cooling pipe 45. In FIG. 4, all of the energy storage elements 30 are omitted.

[0028] By exchanging heat with a coolant liquid or the like via cooling pipe 45, the temperature of each of energy storage elements 30 arranged on temperature adjustment member 40 can be adjusted.

[0029] 2, the front end 47 of the cooling pipe 45 protrudes from the front end surface 42 of the cooling frame 41. By allowing a part of the cooling pipe 45 (in this example, the front end 47) to protrude from the cooling frame 41, it becomes possible to photograph the cooling pipe 45 with the thermal imaging camera 50. The front end 47 of the cooling pipe 45 is an example of the "imaged portion" in the present invention.

[0030] The thermal imaging camera 50 is located in front of (on the left in FIG. 1 ) the power storage module 20. The imaging surface of the thermal imaging camera 50 faces the front end 47 of the cooling pipe 45 protruding from the cooling frame 41, and captures a thermal image G of the front end 47. The thermal image G is an image that visualizes the surface temperature of an object.

[0031] The thermal imaging camera 50 may be an infrared camera that visualizes infrared rays emitted from an object, or may be another camera that can capture a thermal image G. For example, it may be a camera that uses a temperature-sensitive liquid crystal display.

[0032] The thermal imaging camera 50 can be used by attaching it to a housing. The housing is a container that houses the power storage module 20. Figure 5 is a cross-sectional view of the battery panel 100, showing the arrangement of the power storage module 20 within the battery panel.

[0033] The battery panel 100 includes a housing 110 and a plurality of power storage modules 20. The plurality of power storage modules 20 are arranged in multiple stages in the vertical direction inside the housing 110. In this example, thermal imaging cameras 50 are installed on the inner surface of the front wall 120 of the housing 110, corresponding to the power storage modules 20 in each stage.

[0034] 2. Abnormality detection operation of the storage element 30 When any of the plurality of energy storage elements 30 in contact with the temperature adjustment member 40 becomes hot, the heat is transferred from the bottom surface 31B of the energy storage element 30 to the internal liquid via the cooling pipe 45. When the hot liquid circulates through the cooling pipe 45 and moves to the front end 47, the temperature of the front end 47 increases, and a temperature change appears in the thermal image G of the thermal imaging camera 50.

[0035] Fig. 6A is a thermal image G1 of the pipe front end 47 when all the energy storage elements 30 are normal, and Fig. 6B is a thermal image G2 of the pipe front end 47 when a high temperature abnormality occurs in some of the energy storage elements 30. The thermal image G2 in Fig. 6B has changed to a higher temperature than the thermal image G1 in Fig. 6A.

[0036] By monitoring only the thermal image G of the front end 47 of the cooling pipe 45 over time (time series), it is possible to detect abnormalities or signs of abnormalities in the multiple energy storage elements 30 in contact with the temperature adjustment member 40 from changes in the thermal image G.

[0037] The changes in the thermal image G may be displayed on a monitor 70 as shown in FIG. 1 and monitored visually by an observer, or the changes in the thermal image G may be automatically detected by a computer and an alarm may be issued.

[0038] The detection of changes in the thermal image G by the computer may be determined using a threshold value, or may be determined by collecting data on the thermal images G and using machine learning. For example, a machine learning model for determining abnormalities in the energy storage elements 30 may be created by machine learning data on thermal images G under normal conditions, and the abnormality determination may be performed using the machine learning model from input thermal images. The use of machine learning is expected to improve the accuracy of detecting abnormalities in the energy storage elements 30 and their signs.

[0039] 3. Application examples of the power storage device (battery panel 100) 7 is a perspective view of an energy storage system S. The energy storage system S is a system that is connected to a power grid and adjusts the supply and demand of power, and includes, for example, a plurality of battery panels 100 and a PCS panel 150 that are adjacently arranged outdoors. PCS is an abbreviation for Power Conditioning System.

[0040] This technology can also be applied to container-type power storage devices 210A, 210B, and 210C installed alongside a mega solar power generation facility 200A, a wind power generation facility 200B, or a thermal power generation facility 200C, as shown in Fig. 8. Reference numeral 230 denotes a PCS.

[0041] The container-type power storage devices 210A to 210C are power storage devices that house multiple power storage modules 20 and a thermal imaging camera 50 in a container. Furthermore, a thermal image G of the front end 47 of the cooling pipe 45 taken by the thermal imaging camera 50 may be transmitted to a monitoring center 250 via a network N, and the state of the power storage modules 20 of each of the power storage devices 210A to 210C may be remotely and centrally monitored.

[0042] 4.Effectiveness This technology makes it possible to detect temperature changes in each storage element 30 that comes into contact with the temperature adjustment member 40, thereby improving the quality of monitoring the storage module 20 and the accuracy of detecting signs of abnormalities compared to conventional structures that monitor the temperature of only representative points of the storage module 20.

[0043] As exemplified by the battery panel 100 in Fig. 5, the energy storage module 20 is often used while being housed in a space with a limited height. For this reason, it is difficult to capture a thermal image G of the upper surfaces of multiple energy storage elements 30 with a thermal imaging camera 50 from a position sufficiently distant in the height direction (Z direction). Furthermore, when capturing an image from the horizontal direction (when capturing an image from the left in Fig. 5), even if it is possible to capture a thermal image G of the long side surface 31D of the foremost energy storage element 30 (the energy storage element 30 at the left end in Fig. 5), the other energy storage elements 30 are in the shadow of the foremost energy storage element 30, making it difficult to capture a thermal image G of the long side surface 31D.

[0044] This technology solves these problems by focusing on the temperature adjustment member 40, and is advantageous in that it can detect abnormalities and signs of abnormalities not only in the frontmost storage element 30 but also in other storage elements 30 that come into contact with the temperature adjustment member 40, even when the temperature adjustment member 40 is housed in a space with limited height. Typically, among the multiple power storage modules 20 arranged in multiple stages on the battery panel 100, the higher the power storage module 20 arranged, the higher the temperature tends to be due to the heat rising from below. Therefore, the temperature of the temperature adjustment member 40 of the power storage module 20 of each stage may be monitored by a thermal imaging camera 50, and when the power storage module 20 of the upper stage is at a high temperature, it may be determined to be normal, and when the power storage module 20 of a stage below the upper stage is at a high temperature, it may be determined to be abnormal or a sign of abnormality, and an alarm may be issued. It is conceivable that the battery panel 100 incorporates a heat source other than the energy storage elements, and the plurality of energy storage modules 20 are affected by heat from the heat source differently (for example, an energy storage module 20 that is farther away from the heat source is less affected by heat from the heat source, and there is a temperature gradient among the plurality of energy storage modules 20). In such a case, when the temperature difference (for example, absolute value) between the temperature adjustment members 40 of adjacent energy storage modules 20 exceeds a threshold value, it may be determined that an abnormality or a sign of an abnormality has occurred, and an alarm may be issued.

[0045] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0046] (1) In the above embodiment, one thermal imaging camera 50 was used to monitor one energy storage module 20. However, as shown in FIG. 9, one thermal imaging camera 50 may be used to monitor multiple energy storage modules 20 (e.g., multiple energy storage modules 20 arranged at different heights).

[0047] (2) In the above embodiment, the energy storage element is a lithium-ion battery cell. The energy storage element may be a lead-acid battery 270 as shown in FIG. 10 . The lead-acid battery 270 may experience thermal runaway due to heat generation caused by an increase in internal resistance. Thermal runaway occurs when the battery temperature becomes very high due to heat generation during charging, causing the charging current to increase, further increasing the temperature, creating a vicious cycle. Applying this technology to the lead-acid battery 270 makes it possible to detect temperature abnormalities during charging and suppress thermal runaway in the lead-acid battery 270.

[0048] The lead-acid batteries 270 are heavy, and when they are housed in a battery panel for use, the shelf member on which the lead-acid batteries 270 are placed is often made of metal. The metal shelf member comes into contact with the bottom surfaces of the lead-acid batteries 270 and exchanges heat (adjusts temperature) with the lead-acid batteries 270. Therefore, it is conceivable to make the metal shelf member function as a temperature adjustment member. If there is sufficient vertical space within the battery panel or battery compartment that houses the lead-acid batteries 270, a thermal imaging camera disposed above the lead-acid batteries 270 may be used to detect temperature changes in the plurality of lead-acid batteries 270. That is, a method for monitoring a plurality of power storage elements may include taking thermal images of the plurality of power storage elements from above using a thermal imaging camera, and detecting abnormalities or signs of abnormalities in the power storage elements from the thermal images. Conventionally, the internal temperature of the battery panel or the ambient temperature of the battery compartment is measured, and the measured temperature is considered to be the temperature of multiple storage elements. In some cases, a thermistor is attached to a pilot cell (representative cell) to measure the temperature, and the measured temperature is considered to be the temperature of multiple storage elements. In contrast, a higher level of safety and security can be achieved by capturing the changes in the surface temperature of each energy storage element from above using a thermal imaging camera. The Arrhenius law (10°C / 2 times law) can also be applied to thermal images to determine the deterioration and estimate the lifespan of the energy storage elements. While conventionally, deterioration determination and lifespan estimation are performed based on the operational history of each energy storage element or on the measured internal resistance, a thermal imaging camera can be used as an alternative method. This method can be applied to monitoring not only lead-acid batteries 270 but also other energy storage elements such as lithium-ion batteries.

[0049] The above-described method for monitoring multiple storage elements is suitable for application to an emergency power supply such as a DC power supply or an uninterruptible power supply (UPS). The emergency power supply has multiple storage elements (multiple lithium-ion battery cells or multiple lead-acid batteries) in a housing (battery panel or power panel). It is desirable for an emergency power supply device to detect abnormalities or signs of abnormalities in the storage element during normal operation so that it can perform a predetermined discharge in an emergency such as a power outage. During normal operation, the storage element of the emergency power supply device is charged with a minute current (for example, float charging). Therefore, the temperature rise of conductive members such as bus bars due to charging is limited, and the temperature change of the storage element itself can be accurately detected using a temperature adjustment member and a thermal imaging camera.

[0050] (3) In the above embodiment, the temperature adjustment member 40 is configured by the cooling plate 41 and the cooling pipe 45. The temperature adjustment member 40 may have a different configuration as long as it can adjust the temperature of the plurality of energy storage elements 30, the surface temperature of which changes depending on the temperature of each energy storage element 30, and has an imaged portion that can be imaged by the thermal imaging camera 50. Furthermore, instead of a thermal imaging camera, the energy storage device may be provided with a detection unit such as the following. That is, the energy storage device may include a plurality of energy storage elements, a temperature adjustment member that contacts the plurality of energy storage elements to adjust the temperature of the energy storage elements, and a detection unit that detects a temperature change of the temperature adjustment member. For example, instead of detecting the temperature change of a metal shelf member (not shown) on which the lead-acid battery 270 shown in Fig. 10 is placed using a thermal imaging camera, the change may be detected using a detector such as a contact thermistor or a radiation thermometer. The change in the surface temperature of the cooling pipe 45 or the cooling frame 41 shown in Figs. 2 and 4 may also be detected by a detector.

[0051] (4) In the above embodiment, the thermal imaging camera 50 was placed in front of the power storage module 20 and photographed the front end 47 of the cooling pipe 45. The thermal imaging camera 50 may be placed behind the power storage module 20 and photograph the rear end of the cooling pipe 45. Furthermore, if temperature changes due to heat generation from the power storage elements 30 can be detected, the cooling frame 41 may be photographed by the thermal imaging camera 50 as the imaged part.

[0052] (5) The present technology can also be applied to a configuration in which a temperature adjustment member 340 is shared by multiple element blocks 330. The element block 330 is an element group made up of multiple energy storage elements 30 arranged in one direction. The energy storage module 320 shown in FIG. 11 has two element blocks 330A and 330B arranged on the temperature adjustment member 340. The energy storage module 320 also includes a module case 350 that houses the two element blocks 330A and 330B. The module case 350 may have a double structure made up of a resin case 360 ​​that insulates the energy storage elements 30 and a metal case 370 that covers the resin case 360 ​​and is stronger than the resin case 360.

[0053] Each of the element blocks 330A and 330B has a plurality of power storage elements 30 arranged in the short side direction (Y direction) of the temperature adjustment member 340, and the temperature adjustment member 340 has an imaged portion 347 disposed at the end of the short side direction (Y direction) corresponding to each of the element blocks 330A and 330B. When the temperature adjustment member 40 is liquid-cooled, the cooling pipe may be shared by the two element blocks 330A and 330B, or may be disposed separately. [Explanation of symbols]

[0054] 10, 210 Electricity storage device 20,320 Energy storage module 30 Energy storage element 40, 340 Temperature control material 41 Cooling Frame 45 Cooling pipe 47, 347 Front end (imaged part) 50 Thermal Imaging Camera

Claims

1. An electricity storage device, A plurality of storage elements; a temperature adjusting member that contacts the plurality of energy storage elements and adjusts the temperature of the energy storage elements; a thermal imaging camera; The thermal imaging camera captures a thermal image of the temperature adjustment member.

2. The power storage device according to claim 1, the plurality of electric storage elements are arranged side by side in a long side direction or a short side direction of the temperature adjustment member with their bottom surfaces in contact with the temperature adjustment member, The temperature adjustment member has an imaged portion that can be photographed by the thermal imaging camera at an end portion in an arrangement direction of the energy storage elements.

3. The power storage device according to claim 2, The temperature adjustment member is a cooling plate on which the plurality of energy storage elements are placed; a cooling pipe held inside the cooling plate and through which a liquid circulates; The imaged portion is a part of the cooling pipe.

4. The power storage device according to claim 1 or 2, a housing that houses a plurality of power storage elements and the temperature adjustment member; The thermal imaging camera is installed inside the housing.

5. A method for monitoring a plurality of energy storage elements in contact with a temperature adjustment member, comprising: taking a thermal image of the temperature adjustment member; A method for monitoring an electric storage element, comprising: detecting an abnormality or a sign of an abnormality in the electric storage element from a thermal image of the temperature adjustment member.

6. A method for monitoring a plurality of storage elements, comprising: taking a thermal image of the plurality of energy storage elements from above using a thermal imaging camera; A method for monitoring an energy storage element, comprising detecting an abnormality or a sign of an abnormality in the energy storage element from a thermal image.

7. An electricity storage device, A plurality of storage elements; a temperature adjusting member that contacts the plurality of energy storage elements and adjusts the temperature of the energy storage elements; a detector that detects a temperature change of the temperature adjustment member.

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