Power storage pack

Abstract

To properly press a thermistor against a power storage cell even when the position of the thermistor varies in the direction in which a branch portion extends.SOLUTION: A power storage pack includes a plurality of storage cells 11, a frame 30 arranged on the plurality of storage cells 11, a flexible printed circuit board 40 arranged on the frame 30, and a cover that covers at least a portion of the flexible printed circuit board 40. The frame 30 has an opening 32 at a location corresponding to a predetermined position above a predetermined storage cell 11. The flexible printed circuit board 40 has branch portions 47 that branch off from a main body 41 and extend toward the opening 32, and a thermistor 51 arranged at the tip of the branch portion 47. The cover includes a pressing member that presses the thermistor 51 against the top of the predetermined storage cell 11. The longitudinal direction of the thermistor 51 coincides with the direction in which the branch portions 47 extend.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an electricity storage pack. [Background technology]

[0002] JP 2022-097919 A ​​discloses an energy storage module including a laminate, a resin plate, a flexible printed circuit board, a thermistor element, and a cover member. The laminate has a plurality of stacked energy storage cells. The resin plate is placed on the laminate. The flexible printed circuit board is placed on the resin plate and has an electric circuit electrically connected to the plurality of energy storage cells. The thermistor element is provided on the electric circuit and contacts one of the plurality of energy storage cells to detect the temperature of the energy storage cell. The cover member is provided on the resin plate and covers the flexible printed circuit board. The resin plate has an opening at a position where the thermistor element and the energy storage cell contact each other. The flexible printed circuit board has an extension piece extending over the opening of the resin plate and a base portion adjacent to the extension piece and wider than the extension piece. The thermistor element is disposed on the extension piece. The cover member has a protruding portion that protrudes toward the resin plate and bends the extending piece portion to press the thermistor element against the energy storage cell. The base portion is fixed to the resin plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-097919 Summary of the Invention [Problem to be solved by the invention]

[0004] The position of the thermistor is likely to vary in the direction in which the branch portions extend. This variation in the position of the thermistor in the direction in which the branch portions extend may result in the pressing member being unable to properly press the thermistor against the energy storage cell. [Means for solving the problem]

[0005] The energy storage pack disclosed herein includes a plurality of energy storage cells arranged in a predetermined arrangement, a frame body disposed on the plurality of energy storage cells, a flexible printed circuit board disposed on the frame body, and a cover disposed on the frame body and covering at least a portion of the flexible printed circuit board. The frame body has an opening at a location corresponding to a predetermined position above a predetermined energy storage cell. The flexible printed circuit board has a main body, branch portions branching from the main body and extending toward the opening of the frame body, and a thermistor disposed at the tip of the branch portion. The thermistor is disposed at a predetermined position above the predetermined energy storage cell through the opening. The cover includes a pressing member above the opening for pressing the thermistor against the upper portion of the predetermined energy storage cell. The longitudinal direction of the thermistor coincides with the direction in which the branch portions extend.

[0006] In the electricity storage pack disclosed herein, the longitudinal direction of the thermistor coincides with the direction in which the branches extend, so even if the position of the thermistor varies in the direction in which the branches extend, the pressing member can press at least a portion of the thermistor, thereby making it possible to more appropriately press the thermistor against the electricity storage cell even if the position of the thermistor varies in the direction in which the branches extend. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view schematically showing an electricity storage pack. [Figure 2] FIG. 2 is a perspective view schematically showing the electricity storage module. [Figure 3] FIG. 3 is a perspective view schematically showing an electricity storage cell. [Figure 4] FIG. 4 is a side view that schematically shows the energy storage module in a state in which a wiring module is placed on a plurality of energy storage cells. [Figure 5]FIG. 5 is a plan view schematically showing a wiring module placed on a plurality of power storage cells. [Figure 6] FIG. 6 is a plan view schematically showing the tip of a branch portion of a flexible printed circuit board according to a reference example. [Figure 7] FIG. 7 is a side cross-sectional view schematically showing the tip of a branch portion of a flexible printed circuit board according to one embodiment. [Figure 8] FIG. 8 is a side cross-sectional view that schematically shows an example of the tip of the branch when the position of the thermistor is shifted. [Figure 9] FIG. 9 is a plan view schematically showing the tip of a branch portion of a flexible printed circuit board according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the technology disclosed herein will be described below with reference to the drawings. The embodiments described herein are, of course, not intended to limit the present invention. The drawings are schematic and do not necessarily reflect the actual product. Components and parts that perform the same function are appropriately designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. The notation "A to B" indicating a numerical range means "A or greater and B or less" unless otherwise specified. In the following description, the symbols X, Y, and Z in the drawings represent the thickness direction, the width direction perpendicular to the thickness direction, and the height direction perpendicular to the thickness and width directions, respectively. However, these directions are merely provided for convenience of explanation and do not limit the installation form of the electricity storage pack 1 in any way.

[0009] FIG. 1 is a perspective view schematically showing an electricity storage pack 1. The electricity storage pack 1 includes a pack case 5 and a plurality of electricity storage modules 10. The electricity storage pack 1 of this embodiment is an electricity storage pack with a cell-module-pack structure in which a plurality of electricity storage modules 10 are housed inside the pack case 5. Note that the electricity storage pack 1 may also be an electricity storage pack with a cell-to-pack structure in which a plurality of electricity storage cells are housed directly inside the pack case 5. The plurality of electricity storage modules 10 are arranged in a predetermined arrangement inside the pack case 5. In this embodiment, the plurality of electricity storage modules 10 are arranged in the Y direction. Note that while FIG. 1 shows a diagram in which four electricity storage modules 10 are arranged, the number of electricity storage modules 10 included in the electricity storage pack 1 is not particularly limited.

[0010] FIG. 2 is a perspective view that schematically shows the energy storage module 10. The energy storage module 10 includes a plurality of energy storage cells 11 and a restraining member 20. The plurality of energy storage cells 11 are arranged in a predetermined arrangement. In this embodiment, the plurality of energy storage cells 11 are arranged in the X direction. Note that while FIG. 1 shows a diagram in which 12 energy storage cells 11 are arranged in one energy storage module 10, the number of energy storage cells 11 included in one energy storage module 10 is not limited to this. Furthermore, a separator that has heat insulating and electrical insulating properties may be provided between adjacent energy storage cells 11.

[0011] FIG. 3 is a perspective view schematically illustrating the energy storage cell 11. The energy storage cell 11 includes a housing 13, an electrode terminal 15, and a gas release valve 17. The housing 13 is formed in a substantially rectangular parallelepiped shape. An electrode assembly (not shown) is housed inside the housing 13. A pair of electrode terminals 15 are provided at both ends of the upper part of the housing 13 in the Y direction. The electrode terminals 15 are electrically connected to an electrode assembly having a positive electrode and a negative electrode inside the housing 13. One of the pair of electrode terminals 15 is a positive electrode terminal electrically connected to the positive electrode, and the other is a negative electrode terminal electrically connected to the negative electrode. The gas release valve 17 is provided at the center of the upper part of the housing 13 in the Y direction. The gas release valve 17 breaks when the pressure inside the housing 13 reaches or exceeds a predetermined value. As a result, when the pressure inside the housing 13 reaches or exceeds the predetermined value, gas inside the housing 13 is released to the outside of the housing 13.

[0012] In this specification, the term "energy storage cell" refers to the smallest unit of an energy storage device. The term "energy storage device" refers to a device capable of charging and discharging. In this specification, the term "energy storage device" includes batteries generally referred to as lithium ion batteries and lithium secondary batteries, as well as batteries such as lithium polymer batteries. A secondary battery generally refers to a battery capable of repeated charging and discharging through the movement of charge carriers between the positive and negative electrodes. Furthermore, in this specification, the term "energy storage device" also includes capacitors such as lithium ion capacitors and electric double layer capacitors. An energy storage device may use a liquid electrolyte or a solid electrolyte. For example, the secondary battery may be a secondary battery using a so-called liquid electrolyte, or a so-called all-solid-state battery using a solid electrolyte.

[0013] The restraining member 20 shown in FIG. 2 is a member that restrains the multiple energy storage cells 11 arranged in the X direction. The restraining member 20 is configured to apply a required restraining pressure to the multiple energy storage cells 11 arranged in the X direction. The restraining member 20 includes a pair of end plates 22, a pair of side plates 24, and multiple screws. Note that the screws are not shown in FIG. 2. The end plates 22 are arranged at both ends of the multiple energy storage cells 11 in the X direction. The end plates 22 sandwich the multiple energy storage cells 11 in the X direction. The side plates 24 are arranged at both ends of the energy storage cells 11 in the Y direction. The side plates 24 are fastened to the end plates 22 with multiple screws so that a required restraining pressure is applied to the energy storage cells 11. The materials of the end plates 22 and the side plates 24 are not particularly limited. For example, the end plates 22 and the side plates 24 may be made of an aluminum alloy. Note that the configuration of the restraining member 20 is not limited thereto, and a configuration used in an energy storage module may be adopted.

[0014] The energy storage module 10 includes a wiring module 25 placed on the plurality of energy storage cells 11. The wiring module 25 electrically connects the plurality of energy storage cells 11 and is provided to detect the temperature and the like of the energy storage cells 11. The wiring module 25 includes a bus bar 28, a frame 30, a flexible printed circuit board 40, and a cover 60. The wiring module 25 may include other members, but a description thereof will be omitted here.

[0015] Fig. 4 is a side view that schematically shows the energy storage module 10 in a state in which the wiring module 25 is placed on the plurality of energy storage cells 11. Fig. 5 is a plan view that schematically shows the wiring module 25 placed on the plurality of energy storage cells 11. Note that Fig. 5 shows a part of the wiring module 25. Fig. 5 shows the wiring module 25 in a state in which the cover 60 is removed.

[0016] 5 is a member that connects the electrode terminals 15 of adjacent energy storage cells 11. The bus bar 28 is made of a highly electrically conductive material such as aluminum or copper, thereby electrically connecting the multiple energy storage cells 11 to one another.

[0017] As shown in Fig. 4, the frame 30 is disposed on top of the plurality of energy storage cells 11. The frame 30 is made of a resin material that is electrically insulating and heat resistant. The outer shape of the frame 30 is not particularly limited, but in this embodiment, it is formed into a substantially rectangular parallelepiped shape. As shown in Fig. 5, the frame 30 has openings 32 and 34.

[0018] The opening 32 is formed in a portion corresponding to a predetermined position on the top of a predetermined storage cell 11. In this embodiment, the opening 32 is formed above the storage cell 11 located at the end in the X direction. In this embodiment, the opening 32 is formed at a position overlapping with the storage cell 11 located at the end in the X direction when viewed from above. The opening 32 is formed between the electrode terminal 15 and the gas release valve 17 in the Y direction. The opening 32 is provided to bring the flexible printed circuit board 40 into contact with the top of the predetermined storage cell 11.

[0019] The openings 34 are formed above the electrode terminals 15 of each of the plurality of storage cells 11. The openings 34 are formed at positions that overlap the electrode terminals 15 and the bus bars 28 when viewed from above. The openings 34 are provided to allow the bus bars 28 to come into contact with the flexible printed circuit board 40.

[0020] The flexible printed circuit board 40 is a substrate in which an electrical circuit is formed on a substrate made of an insulating base film and a conductive metal foil. The base film is made of, for example, a polyimide film or a polyester film. The conductive metal foil is made of, for example, a copper foil. The flexible printed circuit board 40 is flexible and has the property of maintaining its electrical properties even when deformed.

[0021] As shown in Fig. 4, the flexible printed circuit board 40 is disposed on the frame body 30. As shown in Fig. 5, the flexible printed circuit board 40 includes a main body portion 41, a displacement absorbing portion 43, a busbar joint portion 45, and branch portions 47.

[0022] The shape of the main body 41 is not particularly limited. In this embodiment, the main body 41 is formed in a rectangular shape. The displacement absorbing portion 43 is formed branching off from the main body 41. The displacement absorbing portion 43 is formed by forming a part of the flexible printed circuit board 40 into a substantially U-shape to facilitate deformation. The busbar joint 45 is provided at the tip of the displacement absorbing portion 43. The position of the busbar joint 45 can be adjusted by deforming the displacement absorbing portion 43. The busbar joint 45 is joined to the busbar 28 through the opening 34. As a result, the electrical circuit formed on the flexible printed circuit board 40 is electrically connected to the energy storage cell 11, and the flexible printed circuit board 40 is fixed to the energy storage cell 11.

[0023] The branch portion 47 branches off from the main body portion 41 and extends toward the opening 32 of the frame body 30. In this embodiment, the branch portion 47 extends in the same direction as the direction in which the multiple storage cells 11 are arranged. In other words, the branch portion 47 branches off from the main body portion 41 and extends in the X direction.

[0024] 6 is a plan view schematically showing the tip of the branch 47 of the flexible printed circuit board 40 according to the reference example, in which the cover 60 is removed.

[0025] The flexible printed circuit board 40 further includes a temperature sensor unit 50, a detection line 55, and a ground line 56. The temperature sensor unit 50 includes a thermistor 51 and a capacitor 52. The thermistor 51, the capacitor 52, the detection line 55, and the ground line 56 form part of an electric circuit formed on the flexible printed circuit board 40. The thermistor 51 and the capacitor 52 are connected to the detection line 55 and the ground line 56, respectively.

[0026] The thermistor 51 is an element that detects the temperature of a predetermined storage cell 11. The type of thermistor 51 is not particularly limited, and an NTC thermistor, for example, can be used. The thermistor 51 is disposed at the tip of the branch portion 47. The thermistor 51 is disposed at a predetermined position above the predetermined storage cell 11 through the opening 32. In this example, the thermistor 51 is disposed above the storage cell 11 located at the end in the X direction, and measures the temperature of the storage cell 11 located at the end in the X direction. The thermistor 51 is disposed between the electrode terminal 15 and the gas release valve 17 in the Y direction. The thermistor 51 is formed in a rectangular parallelepiped shape and has a longitudinal direction and a lateral direction when viewed from above.

[0027] Capacitor 52 is electrically connected in parallel with thermistor 51. Capacitor 52 is arranged at the tip of branch portion 47. Capacitor 52 is arranged at a predetermined position above a predetermined storage cell 11 through opening 32. Here, capacitor 52 is arranged above storage cell 11 located at the end in the X direction, and is arranged between electrode terminal 15 and gas release valve 17 in the Y direction. Capacitor 52 is placed at the tip of branch portion 47, lined up with thermistor 51 in the Y direction. Capacitor 52 is formed in a rectangular parallelepiped shape, and has a longitudinal direction and a lateral direction when viewed from above.

[0028] 6, in the electricity storage pack of the reference example, thermistor 51 is mounted on the tip of branch 47 so that its short side direction coincides with the X direction. Therefore, the short side direction of thermistor 51 coincides with the direction in which branch 47 extends. Similarly to thermistor 51, capacitor 52 is mounted on the tip of branch 47 so that its short side direction coincides with the X direction. Therefore, the short side direction of capacitor 52 coincides with the direction in which branch 47 extends. When thermistor 51 and capacitor 52 are arranged in this manner, detection line 55 and ground line 56 can be easily formed in a straight line, and the handling of detection line 55 and ground line 56 is excellent.

[0029] FIG. 7 is a side cross-sectional view schematically showing the tip of a branch portion 47 of the flexible printed circuit board 40. FIG. 7 illustrates the tip of the branch portion 47 with the cover 60 attached. The flexible printed circuit board 40 includes a plate-like member 49. The plate-like member 49 is provided below the tip of the branch portion 47. The plate-like member 49 is provided at a position overlapping the thermistor 51 when viewed from above. The plate-like member 49 is provided to improve thermal conductivity between the thermistor 51 and the energy storage cell 11 and to facilitate mounting of the thermistor 51 on the flexible printed circuit board 40. The plate-like member 49 is preferably made of a material with high thermal conductivity. The plate-like member 49 may be made of aluminum, for example.

[0030] As shown in FIG. 5, the cover 60 is disposed on the frame 30. The cover 60 is provided so as to cover at least a portion of the flexible printed circuit board 40. As shown in FIG. 7, the cover 60 includes a main body 61 and a pressing member 63. The main body 61 is formed in a plate shape. The main body 61 is disposed above the flexible printed circuit board 40 and covers at least a portion of the flexible printed circuit board 40. The material of the cover 60 is not particularly limited, but in this embodiment it is made of a resin material.

[0031] The pressing member 63 is a member for pressing the thermistor 51 against the upper part of a predetermined storage cell 11. In this embodiment, the pressing member 63 presses the thermistor 51 against the upper part of the storage cell 11 located at the end in the X direction. The pressing member 63 bends the branch portion 47 to press the thermistor 51 against the storage cell 11. By pressing the thermistor 51 against the storage cell 11 with the pressing member 63, the thermistor 51 can easily measure the temperature of the storage cell 11 accurately. The pressing member 63 protrudes downward from the main body 61. The pressing member 63 is disposed above the opening 32 and is disposed at a position overlapping with the opening 32 when viewed from above. The pressing member 63 may be formed integrally with the main body 61 as a single member, or may be formed as separate members. If the pressing member 63 is formed as a separate member from the main body 61, the pressing member 63 may be bonded to the main body 61 using an adhesive or the like. The configuration of the pressing member 63 is not particularly limited, but in this embodiment, the pressing member 63 includes a sponge 64 and a holder 65.

[0032] The sponge 64 is a part that comes into contact with the thermistor 51 and presses the thermistor 51 against the energy storage cell 11. The sponge 64 is preferably made of a flexible material. In this embodiment, the sponge 64 is made of a foamed resin material. The shape of the sponge 64 is not particularly limited, but is formed in a rectangular parallelepiped shape.

[0033] The holder 65 is disposed between the sponge 64 and the main body 61. The holder 65 has a holding portion 66 that holds the sponge 64. The holding portion 66 forms the lower portion of the holder 65. There are no particular limitations on the shape of the holding portion 66, but in this embodiment, it is a recess formed in the lower portion of the holder 65. By holding the sponge 64 in the holding portion 66, it is easy to position the sponge 64 and to properly press the thermistor 51 against the storage cell 11. The sponge 64 may be adhered to the holder 65 with an adhesive or the like.

[0034] As described above, the flexible printed circuit board 40 has excellent flexibility. Therefore, when the flexible printed circuit board 40 is pressed against the energy storage cells 11 by the pressing members 63, the degree to which the branch portions 47 are pressed and bent tends to vary.

[0035] Fig. 8 is a side cross-sectional view that schematically shows an example of the tip of the branch 47 when the position of the thermistor 51 is displaced. As shown in Fig. 8, when the degree of bending of the branch 47 varies, the position of the thermistor 51 varies in the direction in which the branch 47 extends. Therefore, when the thermistor 51 is arranged so that the short side direction of the thermistor 51 coincides with the direction in which the branch 47 extends, as in the case of the electricity storage pack 1 shown in Fig. 6, it is likely that the pressing member 63 will not be able to properly press the thermistor 51 against the electricity storage cell 11.

[0036] Furthermore, the energy storage pack 1 configured by arranging a plurality of energy storage cells 11 is prone to large tolerances due to assembly errors and manufacturing dimensional errors of the energy storage cells 11. In particular, the tolerance in the direction in which the plurality of energy storage cells 11 are arranged tends to be large overall because the tolerances of the plurality of energy storage cells 11 are accumulated. In this embodiment, the plurality of energy storage cells 11 are arranged in the X direction, so the tolerance in the X direction tends to be large. Therefore, the positional relationship between the pressing member 63 and the thermistor 51 is likely to be misaligned in the X direction, and there may be cases in which the pressing member 63 is unable to properly press the thermistor 51 against the energy storage cells 11.

[0037] For the reasons described above, when assembling the energy storage pack 1 shown in FIG. 6, the positional relationship in the X direction between the thermistor 51 and the pressing member 63 is left to chance, and it is likely that the pressing member 63 will not be able to properly press the thermistor 51 against the energy storage cell 11.

[0038] FIG. 9 is a plan view schematically illustrating the tip of a branch portion 47 of a flexible printed circuit board 40 of this embodiment. FIG. 9 illustrates the tip of the branch portion 47 with the cover 60 removed. As shown in FIG. 9, in the electricity storage pack 1 of this embodiment, the thermistor 51 is placed on the tip of the branch portion 47 so that its longitudinal direction coincides with the X direction. Therefore, the longitudinal direction of the thermistor 51 coincides with the direction in which the branch portion 47 extends, and coincides with the direction in which the multiple electricity storage cells 11 are arranged. Similarly to the thermistor 51, the capacitor 52 is placed on the tip of the branch portion 47 so that its longitudinal direction coincides with the X direction. Therefore, the longitudinal direction of the capacitor 52 coincides with the direction in which the branch portion 47 extends.

[0039] 9 , in this embodiment, the thermistor 51 is disposed at the tip of the branch 47 so that the longitudinal direction of the thermistor 51 coincides with the extending direction of the branch 47. This makes it easier for at least a portion of the thermistor 51 to overlap with the pressing member 63 when viewed from above, even if the positional relationship between the thermistor 51 and the pressing member 63 is misaligned in the X direction. Therefore, the pressing member 63 can more appropriately press the thermistor 51 against the energy storage cell 11, compared to when the thermistor 51 is disposed so that the lateral direction of the thermistor 51 coincides with the extending direction of the branch 47.

[0040] According to this embodiment, the flexible printed circuit board 40 includes a capacitor 52 connected in parallel to the thermistor 51. This makes it possible to remove noise during temperature detection, thereby improving the accuracy of temperature measurement.

[0041] According to the present embodiment, the longitudinal direction of the thermistor 51 coincides with the X direction, which is the direction in which the energy storage cells 11 are arranged. This allows the pressing member 63 to appropriately press the thermistor 51 against the energy storage cells 11, compared to when the thermistor 51 is arranged so that the lateral direction of the thermistor 51 coincides with the direction in which the energy storage cells 11 are arranged.

[0042] Here, the thermistor 51 is configured to measure the temperature of the energy storage cell 11 located at the end in the X direction, but the thermistor 51 may be configured to measure the temperatures of the other energy storage cells 11. Furthermore, the thermistors 51 may be arranged in two or more energy storage cells 11, respectively, and configured to measure the temperatures of the two or more energy storage cells 11. The opening 32, the branch 47, the pressing member 63, and the like may be arranged above the energy storage cell 11 whose temperature is to be measured. If the energy storage cell 11 whose temperature is to be measured is changed, the arrangement of the opening 32, the branch 47, the pressing member 63, and the like may also be changed as appropriate.

[0043] The technology disclosed herein has been described in various ways. Unless otherwise specified, the embodiments and the like described herein do not limit the present invention. Furthermore, the technology disclosed herein can be modified in various ways, and as long as no particular problems arise, each component and each process described herein can be omitted or combined as appropriate. Furthermore, this specification includes the disclosures described in the following sections.

[0044] Section 1: a plurality of storage cells arranged in a predetermined arrangement; a frame disposed on the plurality of energy storage cells; a flexible printed circuit board disposed on the frame; a cover disposed on the frame and covering at least a portion of the flexible printed circuit board; the frame has an opening at a portion corresponding to a predetermined position above a predetermined storage cell, The flexible printed circuit board is a main body; a branch portion branching from the main body portion and extending toward the opening of the frame body; a thermistor disposed at the tip of the branch portion, the thermistor is disposed at a predetermined position above the predetermined storage cell through the opening, the cover includes a pressing member above the opening for pressing the thermistor against an upper portion of the predetermined storage cell, The longitudinal direction of the thermistor coincides with the direction in which the branch portions extend.

[0045] Section 2: Item 2. The electricity storage pack according to item 1, wherein the flexible printed circuit board includes a capacitor connected in parallel with the thermistor.

[0046] Section 3: the capacitor is disposed at a predetermined position above the predetermined storage cell through the opening; Item 3. The electricity storage pack according to item 2, wherein the longitudinal direction of the capacitor coincides with the direction in which the branch portions extend.

[0047] Section 4: Item 4. The electricity storage pack according to any one of items 1 to 3, wherein the direction in which the plurality of electricity storage cells are arranged coincides with the longitudinal direction of the thermistor. [Explanation of symbols]

[0048] 1 Energy storage pack 10 Energy storage module 11 Energy storage cells 30 Frame 32 Opening 40 Flexible printed circuit board 41 Main body 47 Branch 50 Thermistor 52 Capacitor 60 Cover 63 Pressing member

Claims

1. a plurality of storage cells arranged in a predetermined arrangement; a frame disposed on the plurality of energy storage cells; a flexible printed circuit board disposed on the frame; a cover disposed on the frame and covering at least a portion of the flexible printed circuit board; the frame has an opening at a portion corresponding to a predetermined position above a predetermined storage cell, The flexible printed circuit board is a main body; a branch portion branching from the main body portion and extending toward the opening of the frame body; a thermistor disposed at the tip of the branch portion, the thermistor is disposed at a predetermined position above the predetermined storage cell through the opening, the cover includes a pressing member above the opening for pressing the thermistor against an upper portion of the predetermined storage cell, The longitudinal direction of the thermistor coincides with the direction in which the branch portions extend.

2. The electricity storage pack according to claim 1 , wherein the flexible printed circuit board has a capacitor connected in parallel with the thermistor.

3. the capacitor is disposed at a predetermined position above the predetermined storage cell through the opening; The electricity storage pack according to claim 2 , wherein a longitudinal direction of the capacitor coincides with a direction in which the branch portions extend.

4. The electricity storage pack according to claim 1 , wherein a direction in which the plurality of electricity storage cells are arranged coincides with a longitudinal direction of the thermistor.

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