Power storage device

Abstract

To provide a power storage device capable of more accurately detecting a state of a power storage element.SOLUTION: The energy storage apparatus includes an energy storage device (20), a sensor (81) attached to the energy storage device, a holding member (17) disposed on the energy storage device and configured to hold the sensor in a state where a detection surface of the sensor is exposed toward the energy storage device, and an exterior body configured to house the energy storage device, the sensor and the holding member, wherein an adhesive layer (79) configured to bond the holding member and the energy storage device is interposed between the holding member and the energy storage device.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device including a sensor attached to an electricity storage element. [Background technology]

[0002] Conventionally, there has been known an electric storage device including an electric storage element, an exterior body that houses the electric storage element, and a holding member that is housed in the exterior body and holds a bus bar connected to the electric storage element. Such an electric storage device is provided with a sensor (thermistor) for detecting the state of the electric storage element, and this sensor is fixed in a state in which it is pressed against the electric storage element by the holding member (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-152161 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned energy storage device employs a structure in which the sensor is held and pressed against the energy storage element, but in recent years, methods of adhering the sensor to the energy storage element with an adhesive have been considered to simplify this structure. However, when the sensor is adhered to the energy storage element with an adhesive, there is a risk that the state of the energy storage element cannot be accurately detected due to the adhesive.

[0005] An object of the present invention is to provide an electricity storage device that can more accurately detect the state of an electricity storage element. [Means for solving the problem]

[0006] An energy storage device according to one aspect of the present invention comprises an energy storage element, a sensor attached to the energy storage element, a holding member arranged on the energy storage element and holding the sensor with the detection surface of the sensor exposed toward the energy storage element, and an exterior body that houses the energy storage element, the sensor, and the holding member, an adhesive layer that joins the holding member and the energy storage element is interposed between the holding member and the energy storage element, and the adhesive layer is arranged in a position that does not overlap the detection surface of the sensor in a planar view, the energy storage element comprises a container and a terminal that protrudes outward from the container, the container comprises a container body having an opening formed therein and a lid that closes the opening and on which the terminal is arranged, and the sensor is attached to the lid.

[0007] An energy storage device according to one embodiment of the present invention comprises an energy storage element, a sensor attached to the energy storage element, a holding member arranged on the energy storage element and holding the sensor with the detection surface of the sensor exposed toward the energy storage element, and an exterior body housing the energy storage element, the sensor, and the holding member, wherein an adhesive layer that joins the holding member and the energy storage element is interposed between the holding member and the energy storage element, and the adhesive layer is arranged in a position that does not overlap the detection surface of the sensor in a planar view, and the sensor comprises a sensor main body, an attachment member that houses the sensor main body, and a heat conduction sheet arranged on the outer bottom surface of the attachment member, and the heat conduction sheet is in contact with the energy storage element.

[0008] An energy storage device according to one embodiment of the present invention comprises an energy storage element, a sensor attached to the energy storage element, a holding member arranged on the energy storage element and holding the sensor with the detection surface of the sensor exposed toward the energy storage element, and an exterior body that houses the energy storage element, the sensor, and the holding member, wherein an adhesive layer that bonds the holding member and the energy storage element is interposed between the holding member and the energy storage element, and a thermally conductive adhesive layer that bonds the sensor and the energy storage element is interposed between the detection surface of the sensor and the energy storage element, and the thermal conductivity of the thermally conductive adhesive layer is higher than the thermal conductivity of the adhesive layer. [Effects of the Invention]

[0009] According to the electricity storage device of the present invention, the state of the electricity storage element can be detected more accurately. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing each component of the electricity storage device according to the embodiment. [Figure 3] FIG. 3 is a perspective view showing the appearance of the energy storage device according to the embodiment. [Figure 4] FIG. 4 is a perspective view showing a bus bar frame according to the embodiment. [Figure 5] FIG. 5 is a plan view showing a bus bar frame according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing an assembly structure of a bus bar frame and a sensor according to an embodiment. [Figure 7] FIG. 7 is a plan view of a part of the electricity storage device during a bonding step according to the embodiment. [Figure 8] FIG. 8 is a plan view of a part of the electricity storage device during a bonding step according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The inventors of the present application have found that there are two reasons why the state of an energy storage element cannot be accurately detected when a sensor is attached to the energy storage element with an adhesive. The first is that the presence of adhesive between the sensor and the energy storage element causes the sensor to be subjected to buoyancy from the adhesive, making it impossible to accurately detect the state of the energy storage element. The second is that the presence of adhesive between the sensor and the energy storage element reduces thermal conductivity, making it impossible to accurately detect the state of the energy storage element.

[0012] An energy storage device according to one embodiment of the present invention comprises an energy storage element, a sensor attached to the energy storage element, a holding member arranged on the energy storage element and holding the sensor with the detection surface of the sensor exposed toward the energy storage element, and an exterior body that houses the energy storage element, the sensor, and the holding member, wherein an adhesive layer that bonds the holding member and the energy storage element is interposed between the holding member and the energy storage element, and the adhesive layer is arranged in a position that does not overlap the detection surface of the sensor in a planar view.

[0013] In this way, the adhesive layer that joins the holding member and the energy storage element is positioned so as not to overlap the detection surface of the sensor in a plan view, which prevents the sensor from being subjected to buoyancy from the adhesive that forms the adhesive layer. Therefore, the sensor can be more tightly attached to the energy storage element without the need for a biasing member or the like to press down on the sensor.

[0014] The adhesive layer is positioned so that it does not overlap the detection surface of the sensor in a plan view, so that the adhesive layer is not interposed in the heat conduction path connecting the energy storage element to the detection surface of the sensor, and a decrease in thermal conductivity due to the adhesive layer is unlikely to occur. In this way, the state of the energy storage element can be detected more accurately by improving contact and suppressing a decrease in thermal conductivity.

[0015] The detection surface of the sensor protrudes from the holding member toward the energy storage element, and the amount of protrusion of the detection surface from the holding member may be equal to or greater than the thickness of the adhesive layer.

[0016] With this, the amount by which the detection surface of the sensor protrudes from the holding member is greater than or equal to the thickness of the adhesive layer, so that even if the holding member is subjected to buoyancy from the adhesive and tends to float from its designated position, the detection surface can more reliably abut against the storage element.

[0017] An opening may be formed on the surface of the holding member facing the adhesive layer, the opening being located outward from the detection surface of the sensor.

[0018] The adhesive layer is formed by applying adhesive to the energy storage element or the holding member, and then pressing the energy storage element and the holding member close together. When pressed together, the adhesive spreads between the energy storage element and the holding member. Because an opening is formed in the holding member outside the detection surface, the adhesive that spreads and approaches the detection surface enters the opening. This prevents the adhesive from spreading near the detection surface. In other words, it is possible to more reliably prevent the sensor from being subjected to buoyancy caused by the adhesive.

[0019] The holding member may hold a bus bar connected to the energy storage element, the bus bar being arranged at an end of the holding member, and the sensor being arranged in a central portion of the holding member.

[0020] It is desirable to firmly fix the holding member to the energy storage element in the vicinity of the bus bar. Therefore, it is necessary to apply a sufficient amount of adhesive to the end of the holding member where the bus bar is located. On the other hand, since the center of the holding member is separated from the bus bar, it is possible to reduce the amount of adhesive applied. Because the sensor is located in the center of the holding member, even if the adhesive layer is positioned away from the periphery of the sensor's detection surface, it does not significantly affect the fixation of the holding member. Therefore, it is possible to improve the contact of the sensor with the energy storage element while firmly fixing the vicinity of the bus bar in the holding member.

[0021] The sensor may have a pair of support parts sandwiching the detection surface, and the support parts may be supported by a holding member.

[0022] With this, the sensor is supported by the holding member by a pair of support parts that sandwich the detection surface, making it difficult for the sensor to float even when subjected to buoyancy from the adhesive, and therefore the detection surface can be more reliably abutted against the energy storage element.

[0023] The adhesive layer may be disposed so as to avoid the periphery of the detection surface.

[0024] In this way, since the adhesive layer is arranged to avoid the periphery of the detection surface, the adhesive forming the adhesive layer is less likely to wet and spread onto the detection surface, which more reliably prevents the sensor from being subjected to buoyancy caused by the adhesive.

[0025] A storage device according to one embodiment of the present invention comprises a storage element, a sensor attached to the storage element, a holding member arranged on the storage element and holding the sensor with the detection surface of the sensor exposed toward the storage element, and an exterior body that houses the storage element, the sensor, and the holding member, and a thermally conductive adhesive layer that joins the sensor and the storage element is interposed between the detection surface of the sensor and the storage element.

[0026] According to this, a thermally conductive adhesive layer that bonds the sensor and the energy storage element is interposed between the detection surface of the sensor and the energy storage element, which prevents a decrease in the thermal conductivity of the heat conduction path connecting the energy storage element to the detection surface of the sensor, thereby enabling more accurate detection of the state of the energy storage element.

[0027] Hereinafter, a description will be given of an energy storage device according to an embodiment of the present invention with reference to the drawings. The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated.

[0028] In the following description and drawings, the X-axis direction is defined as the arrangement direction of the energy storage elements, the direction in which the long sides of the containers of the energy storage elements face each other, or the thickness direction of the container. The Y-axis direction is defined as the arrangement direction of the electrode terminals of one energy storage element, or the direction in which the short sides of the containers of the energy storage elements face each other. The Z-axis direction is defined as the arrangement direction of the main body and the outer lid in the exterior body of the energy storage device, or the up-down direction. The Z-axis direction is also the insertion direction when multiple energy storage elements are inserted into the main body opening of the main body. The X-axis direction, Y-axis direction, and Z-axis direction intersect each other (orthogonal in the following embodiments). Depending on the usage mode, the Z-axis direction may not be the up-down direction; however, for convenience of explanation, the Z-axis direction will be described below as the up-down direction. In the following description, for example, the positive side of the X-axis direction refers to the side in the direction of the arrow on the X-axis, and the negative side of the X-axis direction refers to the side opposite to the positive side of the X-axis. The same applies to the Y-axis direction and the Z-axis direction. Furthermore, expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where they are not strictly the same direction or attitude. For example, two directions being orthogonal does not only mean that the two directions are completely orthogonal, but also means that the two directions are substantially orthogonal, i.e., that there is a difference of, for example, a few percent.

[0029] [General explanation of the power storage device] An overall description of a power storage device 1 according to an embodiment will be given with reference to Figures 1 and 2. Figure 1 is a perspective view showing the appearance of the power storage device 1 according to an embodiment. Figure 2 is an exploded perspective view showing each component of the power storage device 1 according to an embodiment.

[0030] The power storage device 1 is a device that can be charged with electricity from an external source and can discharge electricity to the outside, and in this embodiment has a substantially rectangular parallelepiped shape. The power storage device 1 is a battery module (battery assembly) used for power storage, power supply, or the like. Specifically, the power storage device 1 is used as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a gasoline-powered automobile. Examples of the electric railway vehicle include a train, a monorail, and a linear motor car. The power storage device 1 can also be used as a stationary battery for home use or for a power generator, etc.

[0031] 1 and 2, the energy storage device 1 includes an energy storage element 20 and an exterior body 10 that houses the plurality of energy storage elements 20. The exterior body 10 includes a main body 11 that houses the plurality of energy storage elements 20, a bus bar frame 17 that is disposed above the plurality of energy storage elements 20, and an outer lid 12 that covers the bus bar frame 17 from above.

[0032] The exterior body 10 is a rectangular (box-shaped) container (module case) that constitutes the exterior body of the energy storage device 1. In other words, the exterior body 10 is a member that fixes the plurality of energy storage elements 20, the bus bar frame 17, etc. in predetermined positions and protects these elements from impacts and the like.

[0033] The main body 11 is a rectangular cylindrical member with a bottom and an open top, and the open portion is a main body opening 111. The main body opening 111 is substantially rectangular in shape in a plan view. In addition to the plurality of energy storage elements 20 and the bus bar frame 17, the main body opening 111 of the main body 11 also accommodates the plurality of bus bars 33 held by the bus bar frame 17, a connection unit 80 including a control circuit and the like, and a pair of end plates 39.

[0034] The outer lid 12 is a rectangular member that closes the main body opening 111 of the main body 11. The outer lid 12 is joined to the main body 11 while covering the main body opening 111 of the main body 11. The outer lid 12 has a positive electrode external terminal 91 and a negative electrode external terminal 92. The external terminals 91 and 92 are electrically connected to the multiple energy storage elements 20 via the connection unit 80 and the bus bar 33, and the energy storage device 1 charges with electricity from the outside and discharges electricity to the outside via these external terminals 91 and 92. The external terminals 91 and 92 are formed of a conductive metal member such as a copper alloy such as brass, copper, aluminum, or an aluminum alloy.

[0035] The main body 11 and outer lid 12 of the exterior housing 10 are formed from insulating materials such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or composite materials thereof, or from metals or the like with an insulating coating. This prevents the energy storage device 20 and the like from coming into contact with external metal members or the like. The exterior housing 10 may be formed from a conductive material such as metal as long as the electrical insulation of the energy storage device 20 and the like is maintained.

[0036] The energy storage element 20 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The energy storage element 20 has a flattened rectangular parallelepiped (rectangular) shape, and in this embodiment, eight energy storage elements 20 are arranged in the X-axis direction. The shape of the energy storage element 20 and the number of energy storage elements 20 arranged are not limited. The energy storage element 20 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, a capacitor, or a primary battery that allows stored electricity to be used without the user having to charge it. The energy storage element 20 may also be a solid electrolyte battery.

[0037] FIG. 3 is a perspective view showing the appearance of an energy storage element 20 according to an embodiment. As shown in FIG. 3, the energy storage element 20 includes a container 21 and a pair of electrode terminals (a positive electrode terminal 221 and a negative electrode terminal 222). The container 21 contains an electrode assembly, a pair of current collectors (positive electrode side and negative electrode side), an electrolyte (non-aqueous electrolyte), and the like, but these are not shown in the figure. The type of electrolyte is not particularly limited as long as it does not impair the performance of the energy storage element 20, and various types can be selected. Gaskets and the like are disposed between the container 21 and the pair of electrode terminals and the pair of current collectors to improve insulation and airtightness, but these are also not shown. In addition to the above components, spacers disposed on the sides or below the electrode assembly, insulating films encasing the electrode assembly, and the like may also be disposed.

[0038] The container 21 is a rectangular parallelepiped (square or box-shaped) case having a container body 210 with an opening formed therein and a lid 220 that closes the opening of the container body 210. With this configuration, the container 21 has a structure in which the interior can be sealed by accommodating an electrode assembly and the like inside the container body 210 and then joining the container body 210 and the lid 220 by welding or the like. The material of the container 21 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, an aluminum alloy, iron, or plated steel sheet.

[0039] The container body 210 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 21, and has an opening formed on the positive side in the Z axis direction. That is, as shown in Fig. 3, the container body 210 has a pair of long side surfaces 211 on both sides in the X axis direction, a pair of short side surfaces 212 on both sides in the Y axis direction, and a bottom surface 213 on the negative side in the Z axis direction.

[0040] Lid 220 is a rectangular plate-like member that constitutes the lid of container 21, and is disposed extending in the Y-axis direction on the positive side of the Z-axis direction of container body 210. Lid 220 is provided with a liquid injection section (not shown) for injecting the electrolyte, a gas exhaust valve 29 for releasing the pressure by discharging gas when the pressure inside container 21 increases, and the like.

[0041] The positive electrode terminal 221 and the negative electrode terminal 222 are formed of a conductive member such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy, and are provided on the lid 220. Specifically, the positive electrode terminal 221 and the negative electrode terminal 222 are electrode terminals arranged to protrude from the lid 220 of the container 21 toward the bus bar frame 17 (upward, that is, toward the positive side in the Z-axis direction). The positive electrode terminal 221 and the negative electrode terminal 222 are connected to external terminals 91, 92 via at least one bus bar 33 and the connection unit 80, so that the energy storage device 1 can be charged with electricity from the outside and can discharge electricity to the outside.

[0042] The electrode assembly is an electricity storage element (power generating element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is formed by forming a positive electrode active material layer on a positive electrode substrate layer, which is a current collecting foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is formed by forming a negative electrode active material layer on a negative electrode substrate layer, which is a current collecting foil made of a metal such as copper or a copper alloy. As the active material used in the positive electrode active material layer and the negative electrode active material layer, any known material can be used as long as it is capable of absorbing and releasing lithium ions. The electrode assembly may be of any shape, such as a wound electrode assembly formed by winding electrode plates (positive electrode plate and negative electrode plate), a stacked electrode assembly formed by stacking multiple flat electrode plates, or a bellows-shaped electrode assembly formed by folding electrode plates in a bellows shape.

[0043] The current collectors are members (positive electrode current collector and negative electrode current collector) that are electrically connected to the electrode terminals (positive electrode terminal 221 and negative electrode terminal 222) and the electrode body, and have conductivity and rigidity. The positive electrode current collector is made of aluminum or an aluminum alloy, etc., like the positive electrode substrate layer of the positive electrode plate, and the negative electrode current collector is made of copper or a copper alloy, etc., like the negative electrode substrate layer of the negative electrode plate.

[0044] The bus bar 33 is a rectangular plate-like member that is held by the bus bar frame 17 and placed on at least two energy storage elements 20, electrically connecting the positive electrode terminals 221 and the negative electrode terminals 222 of the at least two energy storage elements 20. The bus bar 33 is formed of a conductive member made of metal such as copper, a copper alloy, aluminum, an aluminum alloy, nickel, or a clad material. In this embodiment, five bus bars 33 are used to connect two energy storage elements 20 in parallel to form four sets of energy storage element groups, and the four sets of energy storage element groups are connected in series.

[0045] The connection unit 80 is a unit including a plurality of bus bars and a control board, and connects a group of eight energy storage elements 20 to external terminals 91 and 92. The control board included in the connection unit 80 includes a plurality of electrical components, which form a detection circuit for detecting the state of each energy storage element 20 and a control circuit for controlling charging and discharging. The connection unit 80 is provided with a connector 89 for the detection circuit or control circuit. In this embodiment, the connection unit 80 is fixed to the bus bar frame 17. The detection circuit and the control circuit may be formed on separate boards. The connection unit 80 does not need to include a control board. In this case, a control device disposed outside the energy storage device 1 may control charging and discharging of each energy storage element 20. A sensor 81 (see FIG. 4 ) attached to the energy storage element 20 is electrically connected to the detection circuit. The sensor 81 detects the state of the energy storage element 20. Specifically, examples of the sensor 81 include a temperature sensor (thermistor) that detects the temperature of the power storage element 20, and a voltage sensor that detects the voltage of the power storage element 20.

[0046] The bus bar frame 17 is an example of a holding member arranged above the plurality of energy storage elements 20 (on the side where the positive electrode terminals 221 and the negative electrode terminals 222 are arranged), and in this embodiment, is a member that holds the bus bars 33 and the sensors 81 attached to the energy storage elements 20. More specifically, the bus bar frame 17 is a member that holds the plurality of bus bars 33, the connection unit 80, the sensors 81, and other wiring (not shown), and can regulate the positions of these components. The bus bar frame 17 is provided with a plurality of bus bar openings 17a that hold the plurality of bus bars 33 and expose a portion of each of the plurality of bus bars 33 toward the plurality of energy storage elements 20. The bus bar frame 17 is fixed to the main body 11, and therefore also serves to regulate the upward movement of the plurality of energy storage elements 20 (toward the positive side in the Z-axis direction).

[0047] Bus bar frame 17 arranged above multiple energy storage elements 20 may also be called a "bus bar plate," "internal lid," etc. Bus bar frame 17 is made of an insulating material such as PC, PP, PE, PS, PPS, PPE (including modified PPE), PET, PBT, PEEK, PFA, PTFE, PES, ABS resin, or a composite material thereof, or a metal with an insulating coating.

[0048] The pair of end plates 39 are rectangular plates arranged in the main body 11 at positions that sandwich the plurality of energy storage elements 20 together. Specifically, the pair of end plates 39 are arranged in positions that sandwich the plurality of energy storage elements 20 in the X-axis direction, with an orientation parallel to the YZ plane. In other words, the pair of end plates 39 are arranged so as to overlap the long side surfaces 211 of the containers 21 of the outermost energy storage elements 20. The end plates 39 are formed from metal or the like that is coated with an insulating coating.

[0049] [Busbar frame and sensor assembly structure] Next, the assembly structure of the bus bar frame 17 and the sensor 81 will be described. Fig. 4 is a perspective view showing the bus bar frame 17 according to the embodiment. Specifically, Fig. 4 is a perspective view of the bus bar frame 17 as seen from below. Fig. 5 is a plan view of the bus bar frame 17 according to the embodiment, showing the state before adhesive is applied. Specifically, Fig. 5 is a view of the outer cover 12 and the bus bar frame 17 as seen from below, showing the state after adhesive has been applied. Fig. 6 is a cross-sectional view showing the assembly structure of the bus bar frame 17 and the sensor 81 according to the embodiment. Specifically, Fig. 6 is a cross-sectional view of a cross section including line VV in Fig. 5.

[0050] First, a detailed description will be given of the bus bar frame 17. As shown in Figures 4 and 5, the bus bar frame 17 has a gas path portion 71, an adhesive portion 72, and a bus bar installation portion 73, which are partitioned by multiple pairs of ribs 751-753.

[0051] Gas path portion 71 is disposed in the center of bus bar frame 17 in the Y-axis direction and extends in the X-axis direction. Gas path portion 71 is a path for gas discharged from gas discharge valve 29 of energy storage element 20.

[0052] The adhesive portion 72 is a pair of portions sandwiching the gas path portion 71 in the Y-axis direction, and each extending in the X-axis direction. The adhesive portion 72 includes an adhesive region 721 and a sensor region 722. An adhesive layer 79 (shown by dotted hatching in FIG. 5 ) that bonds the bus bar frame 17 and the plurality of energy storage elements 20 is laminated (applied) on the adhesive region 721. In other words, the surface of the adhesive portion 72 faces the adhesive layer 79.

[0053] The sensor area 722 is an area where the detection surface 87 of the sensor 81 is exposed. In FIG. 5 , the sensor area 722 is indicated by a dashed rectangle. When the overall length of the bus bar frame 17 in the Y axis direction is L, the sensor area 722 is disposed closer to the center than L / 4 from the end of the bus bar frame 17 on the negative side in the Y axis direction. Two sensor areas 722 are provided for the adhesive portion 72 on the negative side in the Y axis direction out of the pair of adhesive portions 72. One sensor area 722 corresponds to the energy storage element 20 located furthest to the negative side in the X axis direction, and the other sensor area 722 corresponds to the fourth energy storage element 20 from the end on the positive side in the X axis direction. In other words, the two sensor areas 722 are spaced apart in the X axis direction in which the multiple energy storage elements 20 are arranged. The sensor area 722 is provided with a first opening 723 that exposes the detection surface 87 of the sensor 81 and multiple second openings 724 that are arranged around the first opening 723. The sensor region 722 includes the entire first opening 723 and the entire second openings 724. Within the sensor region 722, the first opening 723 is disposed in the center, and the multiple second openings 724 are disposed near the boundaries of the sensor region 722.

[0054] 5, the two sensor areas 722 are disposed in the adhesive portion 72 on the negative Y-axis direction side of the gas path portion 71. In other words, the two sensor areas 722 are disposed on the negative Y-axis direction side of the center of the bus bar frame 17 in the Y-axis direction.

[0055] 2, a connector portion 89 of a detection circuit or control circuit included in the connection unit 80 is disposed on the negative side of the center of the connection unit 80 in the Y-axis direction. Wiring (not shown) extending from the sensor 81 (sensor main body 82) disposed in the sensor area 722 is electrically connected to this connector portion 89. Specifically, the connector portion 89 is disposed in a position where a terminal portion to which the wiring of the sensor 81 is connected faces the negative side of the Y-axis direction. The connection unit 80 is disposed approximately in the center of the bus bar frame 17 when viewed in the Z-axis direction, and the connector portion 89 is disposed approximately in the center of the bus bar frame 17 in the X-axis direction.

[0056] The connector portion 89 and the sensor area 722 of the connection unit 80 are both aligned on the negative side of the Y axis direction from the center of the bus bar frame 17 in the Y axis direction. This allows the wiring (not shown) leading out from the sensor 81 (sensor main body 82) to be located on the negative side of the Y axis direction, the same as the connector portion 89. Therefore, there is no need to route extra wiring leading out from the sensor 81. In other words, the wiring can be easily connected to the detection circuit of the connection unit 80 while preventing the wiring from becoming too long.

[0057] 5, in this embodiment, sensor region 722 is not provided in adhesive portion 72 on the positive side in the Y-axis direction of gas path portion 71. Therefore, adhesive layer 79 is provided over the entire area of ​​adhesive portion 72 on the positive side in the Y-axis direction of gas path portion 71, from one end side to the other end side in the X-axis direction.

[0058] The first opening 723 has an opening shape that corresponds to the shape of the detection surface 87 in a plan view. The second opening 724 has an opening shape that is smaller than the first opening 723. The second opening 724 is arranged around the first opening 723. Specifically, as shown in FIG. 6 , the second opening 724 is arranged near the first opening 723 at a distance that is shorter than the length of the first opening 723 in the Y-axis direction. More preferably, the second opening 724 is arranged near the first opening 723 at a distance that is shorter than the length of the second opening 724 in the Y-axis direction.

[0059] 4 and 5, the busbar installation portions 73 are a pair of portions sandwiching the gas path portion 71 and the pair of adhesive portions 72 in the Y-axis direction, and each extends in the X-axis direction. The busbar installation portions 73 are arranged within a range of L / 4 from both ends of the busbar frame 17 in the Y-axis direction. The busbar installation portions 73 are locations where multiple busbars 33 are installed. The busbar installation portions 73 are formed with multiple busbar openings 17a that expose the portions of each busbar 33 that are connected to the energy storage elements 20.

[0060] Pairs of ribs 751 to 753 stand upright from the inner surface of bus bar frame 17 and extend in the X-axis direction. Tips of pairs of ribs 751 to 753 each abut against lid 220 of container 21 of energy storage device 20. Pairs of ribs 751 to 753 function to improve the strength of bus bar frame 17. In the present embodiment, pair of ribs 751 and pair of ribs 752 also function as portions that regulate the position of adhesive layer 79. Specifically, as shown in FIGS. 4 and 5 , pair of ribs 751 are arranged on bus bar frame 17 at positions that sandwich gas path portion 71 in the Y-axis direction. Pairs of ribs 752 are each arranged on bus bar frame 17 at positions that sandwich adhesive portion 72 together with pair of ribs 751. As a result, the adhesive portion 72 is sandwiched between the ribs 751 and 752, and the adhesive (adhesive layer 79) applied to the adhesive portion 72 is restricted by the ribs 751 and 752.

[0061] On the bus bar frame 17, each of the pair of ribs 753 is arranged at a position where the pair of ribs 753 and the pair of ribs 752 sandwich the bus bar installation portion 73. In other words, one of the pair of ribs 753 is arranged at the end of the bus bar frame 17 on the negative side in the Y axis direction, and the other of the pair of ribs 753 is arranged at the end of the bus bar frame 17 on the positive side in the Y axis direction.

[0062] The plurality of pairs of ribs 751 to 753 are provided with a plurality of recesses 754. The recesses 754 are provided at positions corresponding to the edges of each energy storage element 20. An insulating film may be wrapped around the energy storage element 20 to insulate it from adjacent energy storage elements 20. When wrapped around the container 21 of the energy storage element 20, a portion of the insulating film may protrude from the upper end of the container 21. The recesses 754 of each of the ribs 751 to 753 accommodate the portion of the insulating film protruding from the upper end of the container 21, thereby suppressing interference between the insulating film and the bus bar frame 17.

[0063] Next, a detailed description will be given of the sensor 81. As shown in FIG.

[0064] The sensor main body 82 is a part that detects the state of the energy storage element 20. The sensor main body 82 is formed in a rectangular shape in a plan view, and its outer surface is a detection surface 821. The sensor main body 82 is provided with wiring (not shown) that is connected to a detection circuit of the connection unit 80.

[0065] The sensor main body 82 has a generally rectangular parallelepiped shape that is elongated in the X-axis direction. That is, the sensor main body 82 is disposed so that the X-axis direction is its longitudinal direction. The wiring that is led out from the end of the sensor main body 82 in the X-axis direction is led along the X-axis direction. As described above, the sensor main body 82 is disposed in each sensor area 722 shown in FIG. 2 . The wiring that is led out from the end of the sensor main body 82 in the X-axis direction is directed toward the connector portion 89 disposed in the center of the bus bar frame 17 and connected to the connector portion 89 in a state that is aligned along the X-axis direction. This eliminates the need to route extra wiring, and allows for easy connection to the detection circuit of the connection unit 80.

[0066] As shown in FIG. 6 , the mounting member 83 is a member for mounting the sensor main body 82 to the bus bar frame 17. The mounting member 83 is preferably made of a thermally conductive material with relatively high thermal conductivity. The mounting member 83 can be formed by bending a metal plate. The mounting member 83 integrally includes an accommodation portion 84 and a pair of support portions 85, and is approximately the same size as the sensor main body 82 in the X-axis direction. The accommodation portion 84 is a portion for accommodating the sensor main body 82 and is formed in a substantially U-shape when viewed in the X-axis direction. The detection surface 821 of the sensor main body 82 abuts against the inner bottom surface of the accommodation portion 84. Meanwhile, a heat conduction sheet 88 with relatively high thermal conductivity is laminated on the outer bottom surface of the accommodation portion 84. The outer surface of the heat conduction sheet 88 abuts against the lid 220 of the energy storage element 20. This allows heat from the energy storage element 20 to be reliably transferred to the detection surface 821 of the sensor main body 82 via the heat conduction sheet 88 and the mounting member 83. In other words, the outer surface of the thermally conductive sheet 88 can be said to be the detection surface 87 of the sensor 81. The thermally conductive sheet 88 may be made of resin or metal as long as it has insulating properties. The thermally conductive sheet 88 is not in contact with the adhesive layer 79 and is separated from the adhesive layer 79 in the plane in the X-axis and Y-axis directions. When viewed in the X-axis direction, the adhesive layer 79 is disposed between the sensor main body 82 and the energy storage element 20.

[0067] The pair of support portions 85 extend outward along the Y-axis direction from both end portions of the accommodation portion 84. The pair of support portions 85 are each supported by the bus bar frame 17. Specifically, the pair of support portions 85 are fixed to the upper portion of the bus bar frame 17 by adhesive bonding, welding, mechanical joining, or the like.

[0068] When the mounting member 83 is attached to the bus bar frame 17, the entire detection surface 87 of the sensor 81 (the outer surface of the thermally conductive sheet 88) is exposed by the first opening 723 of the sensor area 722. Specifically, as shown in FIG. 6, the detection surface 87 protrudes from the sensor area 722 of the bus bar frame 17 toward the energy storage element 20. A protrusion amount H1 of the detection surface 87 from the bus bar frame 17 (amount of discharge from the surface of the sensor area 722) is equal to or greater than a thickness t1 of the adhesive layer 79. In this state, the detection surface 87 of the sensor 81 abuts against the surface of the lid body 220 of the energy storage element 20. As shown in FIG. 5, the adhesive layer 79 is disposed at a position that does not overlap the detection surface 87 in a plan view, avoiding the detection surface 87 and the periphery of the detection surface 87. The plan view refers to a view from the normal direction (Z-axis direction) of the surface of the lid body 220 to which the adhesive layer 79 is attached.

[0069] In the present embodiment, the case where the sensor 81 includes the heat conduction sheet 88 has been exemplified, but the sensor 81 does not have to include the heat conduction sheet 88. In this case, the outer bottom surface of the housing portion 84 of the mounting member 83 can be used as the detection surface of the sensor 81. If the sensor main body 82 penetrates the housing portion 84 of the mounting member 83 and the detection surface 821 of the sensor main body 82 protrudes from the outer bottom surface of the housing portion 84, the detection surface 821 can also be used as the detection surface of the sensor 81.

[0070] [Bonding process between bus bar frame and energy storage element] Next, a bonding step of bonding bus bar frame 17 and energy storage elements 20 together when manufacturing energy storage device 1 will be described.

[0071] 7 and 8 are plan views of a portion of the energy storage device 1 during the bonding step according to the embodiment. Specifically, Fig. 7 is a plan view showing the inside of the main body 11 of the exterior body 10 in which the plurality of energy storage elements 20 are housed. Fig. 8 is a plan view showing the state in which the bus bar frame 17 is bonded onto the plurality of energy storage elements 20. In Fig. 7, the adhesive layer 79 is shown by dot hatching, and in Fig. 8, the outline of the adhesive layer 79 is shown by a dashed line.

[0072] As shown in FIG. 7 , a plurality of energy storage elements 20 are housed in a state sandwiched between a pair of end plates 39 within the main body opening 111 of the main body 11. The plurality of energy storage elements 20 are fixed with an adhesive between a bottom surface 213 of the container 21, which is on the opposite side of the lid 220 of the container 21 in the Z-axis direction, and an inner surface of the main body 11 facing the bottom surface 213 of the container 21 in the Z-axis direction. In this state, the bonding process is performed. That is, the plurality of energy storage elements 20 are fixed to the main body 11 with an adhesive, and are also fixed to the bus bar frame 17 with an adhesive. The plurality of energy storage elements 20 have adhesive layers sandwiched between the main body 11 and the bus bar frame 17.

[0073] Specifically, in the bonding process, an adhesive is applied to the lid 220 of each container 21 of the multiple energy storage elements 20 using a dispenser or the like to form an adhesive layer 79. Examples of the adhesive include a silicone-based adhesive. When applying the adhesive, the adhesive is applied so as to avoid areas corresponding to each sensor area 722 (shown as dashed rectangles in FIG. 7). These areas are referred to as non-application areas R10. This non-application area R10 allows the adhesive to be applied while avoiding the first opening 723 in the center of each sensor area 722, i.e., the detection surface 87 of the sensor 81.

[0074] On the other hand, the multiple bus bars 33 and the bus bar frame 17 are attached such that the multiple bus bars 33 are assembled to the bus bar frame 17 and integrated with the multiple energy storage elements 20, with the adhesive layer 79 sandwiched between them (see FIGS. 6 and 8). At this time, the bus bar frame 17 is pressed against the adhesive layer 79 on the multiple energy storage elements 20. During this pressing, the adhesive layer 79 is pressed by the bus bar frame 17, and is therefore spread out more than it was in immediately after application.

[0075] At this time, the adhesive layer 79 is restricted from further spreading by the ribs 751 and 752. As the adhesive layer 79 spreads, it also enters the non-application region R10, but is unlikely to reach the detection surface 87 (first opening 723) of the sensor 81 located in the center thereof (see FIG. 6). In particular, since a plurality of second openings 724 are provided around the first opening 723, the adhesive layer 79 that has entered the non-application region R10 enters the second openings 724, making it even more unlikely for the adhesive layer 79 to reach the detection surface 87. In this state, the adhesive layer 79 is positioned so as not to overlap the detection surface 87 of the sensor 81 in a planar view, thereby preventing the sensor 81 from being subjected to buoyancy from the adhesive that forms the adhesive layer 79.

[0076] After the bus bar frame 17 is attached onto the plurality of energy storage elements 20, the adhesive layer 79 is cured while applying a pressing force to the bus bar frame 17 toward the plurality of energy storage elements 20. During curing, the pressing force also acts on the sensor 81, so that the detection surface 87 of the sensor 81 can be more reliably prevented from lifting off the energy storage elements 20.

[0077] As described above, the strength of bus bar frame 17 is increased by the multiple pairs of ribs 751 to 753. Therefore, bus bar frame 17 is less likely to deform even when a pressing force acts on bus bar frame 17. In other words, the deformation of bus bar frame 17 also prevents sensor 81 from floating above energy storage elements 20.

[0078] 6 illustrates a case where, after curing, the protrusion amount H1 of the detection surface 87 and the thickness t1 of the adhesive layer 79 are equal. However, because the adhesive layer 79 is not present around the periphery of the detection surface 87, i.e., around the first opening 723, the bus bar frame 17 is able to elastically deform around the first opening 723. As a result, if the protrusion amount H1 of the detection surface 87 is greater than the thickness t1 of the adhesive layer 79, the bus bar frame 17 can elastically deform to absorb the difference. Furthermore, after elastic deformation, the restoring force of the bus bar frame 17 acts on the detection surface 87, allowing the detection surface 87 to abut against the energy storage element 20 more reliably.

[0079] In the bonding step according to the present embodiment, an example has been given in which adhesive is applied to lid body 220 of each container 21 of a plurality of energy storage elements 20 to form adhesive layer 79. However, in the bonding step, adhesive may be applied to bus bar frame 17 to form adhesive layer 79.

[0080] Thereafter, the positive electrode terminals 221 and negative electrode terminals 222 of the plurality of energy storage elements 20 are connected to the plurality of bus bars 33 by a welding method such as laser welding, and an outer edge portion of the bus bar frame 17 at a different position spaced apart from the adhesive layer 79 is fixed to the main body 11 by thermal caulking. Next, the connection unit 80 is arranged on the positive side of the bus bar frame 17 in the Z axis direction. At this time, wiring for measuring temperature of the sensor 81 and wiring for measuring voltage connected to the plurality of bus bars 33 are connected to a connector portion 89 of the connection unit 80. Next, a portion of the outer lid 12 made of resin and a portion of the main body 11 also made of resin are melted by heat, and the melted portions are pressed against each other, thereby assembling the outer lid 12 to the main body 11.

[0081] [Effects, etc.] As described above, the energy storage device 1 of this embodiment includes an energy storage element 20, a sensor 81 attached to the energy storage element 20, a bus bar frame 17 (holding member) arranged on the energy storage element 20 and holding the sensor 81 with the detection surface 87 of the sensor 81 exposed toward the energy storage element 20, and an exterior body 10 that houses the energy storage element 20, the sensor 81, and the bus bar frame 17, and an adhesive layer 79 that bonds the bus bar frame 17 and the energy storage element 20 is interposed between the bus bar frame 17 and the energy storage element 20, and the adhesive layer 79 is arranged in a position that does not overlap the detection surface 87 of the sensor 81 in a planar view.

[0082] With this, adhesive layer 79 that joins bus bar frame 17 and energy storage element 20 is disposed at a position that does not overlap detection surface 87 of sensor 81 in a plan view, which prevents sensor 81 from being directly subjected to buoyancy from the adhesive that forms adhesive layer 79. Therefore, the abutment of sensor 81 with energy storage element 20 can be improved even without a biasing portion or the like for pressing down sensor 81. In this way, the abutment of sensor 81 with energy storage element 20 can be improved with a simple structure.

[0083] In particular, because adhesive layer 79 is disposed so as to avoid the periphery of detection surface 87, the adhesive forming adhesive layer 79 is less likely to wet and spread to detection surface 87. This more reliably prevents sensor 81 from being subjected to the buoyancy caused by the adhesive.

[0084] Furthermore, since the adhesive layer 79 is disposed at a position that does not overlap the detection surface 87 of the sensor 81 in a plan view, the adhesive layer 79 is not interposed in the heat conduction path connecting the energy storage element 20 to the detection surface of the sensor 81, and a decrease in thermal conductivity due to the adhesive layer 79 is unlikely to occur. In this way, the state of the energy storage element 20 can be detected more accurately by improving contact and suppressing a decrease in thermal conductivity.

[0085] The detection surface 87 of the sensor 81 protrudes from the bus bar frame 17 toward the energy storage device 20, and the amount H1 of protrusion of the detection surface 87 from the bus bar frame 17 is equal to or greater than the thickness t1 of the adhesive layer 79.

[0086] As a result, the protrusion amount H1 of the detection surface 87 of the sensor 81 from the bus bar frame 17 is greater than or equal to the thickness t1 of the adhesive layer 79, so that even if the bus bar frame 17 is subjected to buoyancy from the adhesive and tends to float from its predetermined position, the detection surface 87 can be more reliably abutted against the storage element 20.

[0087] A second opening 724 (opening) is formed on the surface of the bus bar frame 17 facing the adhesive layer 79, and is located outward from the detection surface 87 of the sensor 81.

[0088] The adhesive layer 79 is formed by applying an adhesive to the energy storage element 20 or the bus bar frame 17, and then pressing the energy storage element 20 and the bus bar frame 17 close to each other. When pressed together, the adhesive spreads between the energy storage element 20 and the bus bar frame 17. Since the bus bar frame 17 has a second opening 724 formed outward of the detection surface 87, the adhesive that spreads and approaches the detection surface 87 enters the second opening 724. This makes it possible to prevent the adhesive from spreading near the detection surface 87. In other words, it is possible to more reliably prevent the sensor 81 from being subjected to the buoyancy force caused by the adhesive.

[0089] The bus bar frame 17 holds the bus bar 33 connected to the energy storage element 20, the bus bar 33 being arranged at the end of the bus bar frame 17, and the sensor 81 being arranged in the center of the bus bar frame 17.

[0090] It is desirable to firmly fix the bus bar frame 17 to the energy storage elements 20 in the vicinity of the bus bar 33. For this reason, it is necessary to apply a sufficient amount of adhesive to the end of the bus bar frame 17 where the bus bar 33 is arranged. On the other hand, since the central portion of the holding member is separated from the bus bar 33, it is possible to reduce the amount of adhesive applied. Since the sensor 81 is arranged in the central portion of the bus bar frame 17, even if the adhesive layer 79 is arranged around the periphery of the detection surface 87 of the sensor 81, this does not significantly affect the fixation of the bus bar frame 17. Therefore, it is possible to improve the contact of the sensor 81 with the energy storage elements 20 while firmly fixing the vicinity of the bus bar 33 in the bus bar frame 17.

[0091] In particular, in this embodiment, the sensor area 722 is arranged closer to the center than L / 4 from the end on the negative side in the Y-axis direction of the bus bar frame 17, and the bus bar installation section 73 is arranged within a range of L / 4 from both ends of the bus bar frame 17 in the Y-axis direction. As a result, simply by arranging the sensor 81 in the sensor area 722, the sensor 81 can be reliably arranged in the center of the bus bar frame 17, and simply by installing the bus bar 33 in the bus bar installation section 73, the bus bar 33 can be reliably arranged at the end of the bus bar frame 17.

[0092] The sensor 81 has a pair of support parts 85 that sandwich a detection surface 87 , and the support parts 85 are supported by the bus bar frame 17 .

[0093] With this, sensor 81 is supported on bus bar frame 17 by a pair of support parts 85 that sandwich detection surface 87, making it difficult for sensor 81 to float even when subjected to buoyancy from the adhesive. Therefore, detection surface 87 can be more reliably brought into contact with energy storage element 20.

[0094] [others] Although the power storage device according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. In other words, the embodiment disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0095] For example, in the above embodiment, bus bar frame 17 is given as an example of a holding member that holds sensor 81. However, a member other than bus bar frame 17 may be used as the holding member as long as the member holds sensor 81 with detection surface 87 of sensor 81 exposed toward energy storage device 20.

[0096] In the above embodiment, the adhesive layer 79 is disposed so as to avoid the periphery of the detection surface 87 of the sensor 81, but the adhesive layer 79 may be disposed in a position that does not overlap the detection surface 87 in a plan view. In other words, the adhesive layer 79 may be disposed so as to avoid only the detection surface 87.

[0097] In the above embodiment, the adhesive layer 79 is disposed so as to avoid the periphery of the detection surface 87 of the sensor 81. However, a thermally conductive adhesive layer may be interposed between the detection surface 87 of the sensor 81 and the energy storage element 20. Specifically, this can be achieved by, for example, replacing the thermally conductive sheet 88 shown in FIG. 6 with a thermally conductive adhesive layer. In this case, the thermally conductive adhesive layer is not included in the sensor 81 but serves as a portion that joins the sensor 81 and the energy storage element 20. The thermally conductive adhesive layer is formed of an adhesive having a thermal conductivity higher than that of the adhesive layer 79. The thermally conductive adhesive layer may be formed of an adhesive having a thermal conductivity equal to or greater than that of the mounting member 83. Alternatively, the thermally conductive adhesive layer may be formed of an adhesive having a thermal conductivity equal to or greater than that of the container 21 of the energy storage element 20.

[0098] In this way, a thermally conductive adhesive layer that bonds the sensor 81 and the energy storage element 20 is interposed between the detection surface 87 of the sensor 81 and the energy storage element 20, which prevents a decrease in the thermal conductivity of the heat conduction path that connects the energy storage element 20 to the detection surface 87 of the sensor 81. This allows the state of the energy storage element 20 to be detected more accurately.

[0099] When a thermally conductive adhesive layer is interposed between detection surface 87 of sensor 81 and power storage element 20, adhesive layer 79 may be omitted.

[0100] In the above embodiment, a case where a plurality of second openings 724 are provided around first opening 723 has been exemplified, but there may be only one second opening 724, or there may be no second openings 724 at all.

[0101] In the above embodiment, the case where the sensor 81 is disposed in the center of the bus bar frame 17 has been exemplified, but it may also be disposed at an end of the bus bar frame 17.

[0102] In the above embodiment, the sensor 81 has been exemplified as having a pair of support parts 85. However, it is sufficient that the sensor 81 is provided with at least one support part 85.

[0103] In the above embodiment, the energy storage device 1 having a plurality of energy storage elements 20 has been exemplified, but the energy storage device may also be one having one energy storage element.

[0104] Any combination of the components included in the above embodiments is also included within the scope of the present invention. [Industrial Applicability]

[0105] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0106] 1. Energy storage device 10. Exterior body 11 Main body 12 Outer lid 17 Busbar frame 17a Busbar opening 20 Energy storage element 21 Container 29 Gas exhaust valve 33 Busbar 39 End Plate 71 Gas path section 72 Adhesive part 73 Busbar installation section 79 Adhesive layer 80 connection units 81 Sensors 82 Sensor body 83 Mounting material 84 Storage unit 85 Support part 87 Detection surface 88 Thermal Conduction Sheet 89 Connector part 91, 92 External terminals 111 Main body opening 210 Container body 211 Long side 212 short side 213 bottom 220 Lid 221 Positive terminal 222 Negative terminal 721 Adhesive area 722 Sensor Area 723 First opening 724 Second opening (opening) 751, 752, 753 Ribs 754 recess 821 detection surface H1 protrusion amount R10 Uncoated area t1 thickness

Claims

1. A storage element; a sensor attached to the power storage element; a holding member that is disposed on the power storage element and holds the sensor with a detection surface of the sensor exposed toward the power storage element; an exterior body that houses the storage element, the sensor, and the holding member, an adhesive layer that bonds the holding member and the energy storage element is interposed between the holding member and the energy storage element; the adhesive layer is disposed at a position not overlapping the detection surface of the sensor in a plan view, the energy storage element includes a container and a terminal protruding outward from the container; the container includes a container body having an opening formed therein, and a lid body that closes the opening and on which the terminal is disposed, The sensor is attached to the lid. Energy storage device.

2. A storage element; a sensor attached to the power storage element; a holding member that is disposed on the power storage element and holds the sensor with a detection surface of the sensor exposed toward the power storage element; an exterior body that houses the storage element, the sensor, and the holding member, an adhesive layer that bonds the holding member and the energy storage element is interposed between the holding member and the energy storage element; the adhesive layer is disposed at a position not overlapping the detection surface of the sensor in a plan view, The sensor includes a sensor body, a mounting member that houses the sensor body, and a heat-conductive sheet that is disposed on an outer bottom surface of the mounting member; The thermally conductive sheet is in contact with the power storage element. Energy storage device.

3. A storage element; a sensor attached to the power storage element; a holding member that is disposed on the power storage element and holds the sensor with a detection surface of the sensor exposed toward the power storage element; an exterior body that houses the storage element, the sensor, and the holding member, an adhesive layer that bonds the holding member and the energy storage element is interposed between the holding member and the energy storage element, and a thermally conductive adhesive layer that bonds the sensor and the energy storage element is interposed between the detection surface of the sensor and the energy storage element; The thermal conductivity of the thermally conductive adhesive layer is higher than the thermal conductivity of the adhesive layer. Energy storage device.

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