JP6379766B2 - Battery module - Google Patents

Description

  The present invention relates to a battery module in which a thermistor is attached to a battery cell.

A battery module having a plurality of battery cells is provided with a thermistor for detecting the temperature of the battery cells (see, for example, Patent Document 1).
In the secondary battery device described in Patent Document 1, a cell unit in which a plurality of battery cells are connected in parallel is housed in a center case. The thermistor is provided in the battery cell provided in the position where the temperature becomes highest among the plurality of battery cells and the battery cell provided in the position where the temperature becomes lowest. On the side wall of the center case, an elongated belt-like groove is formed on the inner surface of the side wall facing the battery cell to which the thermistor is attached. The thermistor is accommodated in the groove.

JP 2012-38468 A

  By the way, when the thermistor is not properly attached, such as when the thermistor is attached to the battery cell in a misaligned state, the temperature of the battery cell cannot be measured correctly. Further, when vibration is applied to the secondary battery device, the thermistor may come out of the groove. For this reason, when attaching a thermistor to a battery cell, it is desired to confirm the attachment state of the thermistor.

  The objective of this invention is providing the battery module which can confirm the attachment state of a thermistor.

  A battery module that solves the above problems includes a battery cell, a thermistor attached to the battery cell, a cover that is provided facing the attachment surface of the battery cell to which the thermistor is attached, and covers the attachment surface; The said cover has a visual recognition part which can visually recognize the said thermistor when the said cover is attached.

  According to this, after attaching a thermistor to a battery cell, the attachment state of a thermistor can be confirmed from a visual recognition part. Even if the thermistor is covered with a cover, the attachment state of the thermistor can be confirmed from the visual recognition part.If the thermistor is attached in a misaligned state, the cover should be removed and the thermistor attached again. it can. For this reason, it is suppressed that the thermistor is attached in a misaligned state, and the thermistor is unlikely to be detached from the battery cell.

  The battery module has a positioning surface with which the thermistor contacts and a battery holder that holds the battery cell, and the visual recognition portion is at a position where the contact portion between the positioning surface and the thermistor can be visually recognized. It is preferable to be provided. According to this, the attachment state of the thermistor can be confirmed by confirming the contact state between the positioning surface and the thermistor. For this reason, it is easy to confirm the attachment state of the thermistor.

  About the said battery module, it is preferable that the said visual recognition part is provided in the position facing the contact part of the said positioning surface and the thermistor. According to this, it is easy to confirm the attachment state of the thermistor.

  With respect to the battery module, the visual recognition part is a confirmation hole that penetrates the cover, and the battery holder has an engagement claw that engages with an edge of the confirmation hole to suppress the displacement of the cover. preferable. According to this, the positional deviation of the cover can be suppressed.

  With respect to the battery module, the visual recognition part is a confirmation hole that penetrates the cover, and the cover includes a flow path partition part that partitions a flow path of gas discharged from the battery cell, and a terminal of the battery cell. A storage area partition section that partitions the terminal storage area to be stored, wherein the thermistor is provided in a region between the flow path and the terminal storage area, and the confirmation hole is formed between the flow path partition section and the flow path partition section. It is preferable that it is provided between the storage area section.

  According to this, the confirmation hole does not communicate with the flow path and the terminal accommodating region. Therefore, the gas discharged from the battery cell leaks from the confirmation hole to the outside of the flow path, leaks from the confirmation hole to the outside of the flow path, or foreign matter enters the terminal accommodation area from the confirmation hole and the battery cell is short-circuited. Is suppressed.

  In the battery module, the cover is preferably provided with a pressing portion that presses the thermistor against the battery cell. According to this, the position shift of the thermistor can be suppressed by the cover.

  According to the present invention, the attachment state of the thermistor can be confirmed.

The perspective view which shows the battery module of embodiment. The 2-2 sectional view taken on the line of FIG. 1 which shows the battery module of embodiment. (A) is a perspective view which shows the 1st battery holder of embodiment, (b) is a perspective view which shows the 2nd battery holder of embodiment. The partially broken perspective view which expands and shows the latching claw of embodiment. The partially broken perspective view which expands and shows the guide member of embodiment. The perspective view which shows the cover of embodiment. The partially broken perspective view which shows the attachment aspect of the thermistor of embodiment. The figure which shows typically the positional relationship of the confirmation hole and thermistor of embodiment.

Hereinafter, an embodiment of the battery module will be described.
As shown in FIGS. 1 and 2, the battery module 10 has a plurality of battery cells 11. Each battery cell 11 is held by individual battery holders 20 and 40. In the present embodiment, the battery cells 11 held by the first battery holder 20 and the battery cells 11 held by the second battery holder 40 are alternately arranged in parallel. The plurality of battery cells 11 are sandwiched between end plates 18 and 19 provided on both sides of the battery cells 11 in the juxtaposed direction.

  The battery cell 11 (for example, a lithium ion secondary battery or a nickel metal hydride storage battery) has a case 12. An electrode assembly 13 is accommodated in the case 12. The case 12 includes a bottomed box-like case main body 14 that houses the electrode assembly 13 and a rectangular plate-like lid 15 that closes the opening of the case main body 14. The lid 15 is provided with two terminals 16 (a positive terminal and a negative terminal) protruding in the thickness direction of the lid 15. In the lid 15, a pressure release valve 17 that is opened when the internal pressure of the case 12 exceeds a specified pressure is provided between the two terminals 16. The “specified pressure” is set to a pressure at which the pressure release valve 17 is broken before the case 12 is damaged when the internal pressure of the case 12 increases.

Next, the first battery holder 20 and the second battery holder 40 will be described. First, the common part of the 1st battery holder 20 and the 2nd battery holder 40 is demonstrated.
As shown in FIGS. 3A and 3B, each battery holder 20, 40 has a first covering wall 21 having a rectangular flat plate shape. At both ends in the longitudinal direction of the first covering wall 21, a rectangular flat plate-like second covering wall 22 and a third covering wall 23 extending in the thickness direction of the first covering wall 21 are provided. A region surrounded by the first covering wall 21, the second covering wall 22, and the third covering wall 23 is a housing portion S in which the battery cell 11 is housed. The first longitudinal end portion 22a of the second covering wall 22 (the end opposite to the end portion on which the first covering wall 21 is provided) and the first longitudinal end portion 23a of the third covering wall 23 (the first end portion). A rectangular flat plate-like fourth covering wall 24 extending between the first ends 22c and 23c in the short direction of the respective covering walls 22 and 23 is provided at the end opposite to the end where the covering wall 21 is provided. Is provided. The thickness direction of the fourth covering wall 24 coincides with the short direction of the covering walls 22 and 23, and the longitudinal direction thereof coincides with the opposing direction of the second covering wall 22 and the third covering wall 23. The direction perpendicular to the thickness direction and the longitudinal direction of the fourth covering wall 24 is the short direction of the fourth covering wall 24.

  Further, a terminal accommodating portion 25 that is U-shaped on one end face in the short direction of the fourth covering wall 24 at both longitudinal ends of the fourth covering wall 24 and opens in the thickness direction of the fourth covering wall 24. Are provided, and each terminal accommodating portion 25 is connected to the second covering wall 22 and the third covering wall 23. A wall portion 25 a is erected from the periphery of the terminal accommodating portion 25.

  On one end surface in the short direction of the fourth covering wall 24, a quadrangular columnar first column member 26 is provided adjacent to the terminal accommodating portion 25 connected to the second covering wall 22. Further, on the one end face in the short direction of the fourth covering wall 24, a quadrangular columnar second column member 27 is provided adjacent to the terminal accommodating portion 25 connected to the third covering wall 23. The shafts of the column members 26 and 27 extend in the short direction of the covering walls 22 and 23. Each column member 26, 27 is provided with an insertion hole 26 a, 27 a penetrating in the axial direction of each column member 26, 27.

  The longitudinal direction first end portion 22a of the second covering wall 22 and the longitudinal direction first end portion 23a of the third covering wall 23 are connected to the covering walls 22 and 23, and the longitudinal direction of the covering walls 22 and 23 is provided. A projecting wall 28 having a rectangular flat plate shape extending in the direction is provided. Convex portions 29 projecting in the thickness direction of the projecting walls 28 are provided on the surfaces of the projecting walls 28 connected to the covering walls 22 and 23 facing each other.

  Square columnar legs 30 are provided at the second longitudinal end portion 22 b of the second covering wall 22 and the second longitudinal end portion 23 b of the third covering wall 23. The axis of the leg portion 30 extends in the short direction of the covering walls 22 and 23. The leg portion 30 is provided with an insertion hole 30 a penetrating in the axial direction of the leg portion 30.

Next, different parts of the battery holders 20 and 40 will be described.
As shown in FIG. 3A, the first battery holder 20 has locking claws 31 and 32 that protrude from the column members 26 and 27 in the direction opposite to the housing portion S. The locking claws 31 and 32 are provided on the first column member 26 and the second column member 27, respectively. The first locking claw 31 provided on the first column member 26 and the second locking claw 32 provided on the second column member 27 are located slightly shifted in the axial direction of the column members 26 and 27. ing.

  As shown in FIG. 4, the locking claws 31, 32 have a plate-like protruding portion 33 protruding from the column members 26, 27 and a return portion 34 provided at the tip of the protruding portion 33. The return portion 34 has a triangular plate shape, and tapers as it goes to the tip, in other words, as it gets away from the protruding portion 33.

As shown in FIG. 3 (b), the second battery holder 40 has a frame-shaped guide member 41. The guide member 41 extends from the fourth covering wall 24 along the first column member 26.
As shown in FIG. 5, the guide member 41 has a plate-like base portion 42 provided on the fourth covering wall 24. A plate-like first guide portion 43 extends from the base portion 42 along the first column member 26. The first guide portion 43 is L-shaped and is connected to the first column member 26. A plate-like second guide part 44 provided at a distance from the first guide part 43 extends in parallel with the first guide part 43 from the base part 42.

  As shown in FIG. 2, a thermistor 51 that detects the temperature of the battery cell 11 is attached to the outer surface of the battery cell 11. The thermistor 51 is attached to the surface of the lid 15 in the thickness direction. Therefore, the attachment surface 15 a to which the thermistor 51 of this embodiment is attached is a surface located outside the battery cell 11 among the surfaces in the thickness direction of the lid 15. The thermistor 51 is provided in the frame of the guide member 41. When the thermistor 51 is attached, positioning is performed by bringing the thermistor 51 into contact with the positioning surface 45 that is the surface of the base 42 that divides the frame of the guide member 41.

  As shown in FIG. 1, the battery module 10 has a cover 61. The cover 61 is provided for the purpose of adhering foreign matter to the terminals 16 of the battery cells 11, for example. The cover 61 is disposed between the protruding walls 28.

  As shown in FIG. 6, the cover 61 has a rectangular plate-shaped main body 62. Plate-like standing portions 63 that stand in the thickness direction of the main body 62 are provided at both ends in the short direction of the main body 62. The standing portion 63 extends over the entire length of the main body 62.

  Among the surfaces in the thickness direction of the main body 62, the first partition wall 64 and the second partition wall 65 having a rectangular flat plate shape are formed on the surface different from the surface on which the standing portion 63 is provided by the center in the short direction of the main body 62. And are provided. The partition walls 64 and 65 are provided with an interval in the short direction of the main body 62 and extend over the entire longitudinal direction of the main body 62.

  The main body 62 is provided with a plurality of locking holes 66 to 68 penetrating in the thickness direction along the first partition wall 64. Specifically, a first locking hole 66, a second locking hole 67, and a third locking hole 68 are provided along the first partition wall 64 at intervals in the longitudinal direction of the main body 62. The main body 62 is provided with a single locking hole 69 penetrating in the thickness direction along the second partition wall 65 and a plurality of confirmation holes 70 and 71 as visual recognition parts. Specifically, the fourth locking hole 69, the first confirmation hole 70, and the second confirmation hole 71 are provided along the second partition wall 65 at intervals in the longitudinal direction of the main body 62. Each of the locking holes 66 to 69 has a square shape. Each of the check holes 70 and 71 includes a lock portion 72 having the same shape as the lock holes 66 to 69, and a check portion 73 that is connected to the lock portion 72 and has a larger opening area than the lock portion 72. have. The first locking hole 66 and the fourth locking hole 69 are adjacent to each other in the lateral direction of the main body 62 with the partition walls 64 and 65 interposed therebetween. The second locking hole 67 and the first confirmation hole 70 are adjacent to each other in the lateral direction of the main body 62 with the partition walls 64 and 65 interposed therebetween. The third locking hole 68 and the second confirmation hole 71 are adjacent to each other in the lateral direction of the main body 62 with the partition walls 64 and 65 interposed therebetween. The first locking hole 66 and the fourth locking hole 69, the second locking hole 67 and the locking part 72 of the first confirmation hole 70, the third locking hole 68 and the locking part 72 of the second confirmation hole 71, Are provided with a slight shift in the longitudinal direction of the main body 62, and the shift width is the shift width between the first locking claw 31 and the second locking claw 32 provided on the column members 26 and 27, respectively. It is the same.

  Of the surface in the thickness direction of the main body 62, a projection portion 74 that protrudes in the thickness direction of the main body 62 is provided on the surface on which the partition walls 64 and 65 are provided. One protrusion 74 is provided around each of the confirmation holes 70 and 71. A rubber sponge 75 is provided at the tip of the protrusion 74.

  As shown in FIG. 2, the standing portion 63 of the cover 61 is provided along the protruding wall 28. A convex portion 29 is located at the tip of the standing portion 63 of the cover 61. The cover 61 faces the mounting surface 15a. The attachment surface 15 a is covered with the cover 61. The main body 62 of the cover 61 is supported by wall portions 25 a and column members 26 and 27 provided around the terminal accommodating portion 25. The locking claws 31 and 32 of the first battery holder 20 are locked to the edges of the locking portions 72 of the locking holes 66 to 69 and the confirmation holes 70 and 71, respectively.

  The tips of the partition walls 64 and 65 are in contact with the lid 15 of the battery cell 11. The partition walls 64 and 65 are provided so as to sandwich the pressure release valve 17, and thereby, the flow path 81 through which the gas discharged from the battery cell 11 flows by the partition walls 64 and 65, the lid 15, and the main body 62. Is partitioned. Therefore, the part between the partition walls 64 and 65 and the partition walls 64 and 65 in the main body 62 becomes a flow path partition part.

  Further, the terminal accommodating region 82 is defined by the main body 62 of the cover 61, the lid 15 of the battery cell 11, the respective coating walls 22 and 23, the terminal accommodating portion 25, the column members 26 and 27, and the wall portion 25 a. The terminal accommodating area 82 accommodates the terminal 16 of the battery cell 11. Accordingly, the portion of the main body 62 facing the terminal accommodating region 82 becomes the accommodating region partitioning portion.

  An electronic component 91 is placed on the cover 61. The electronic component 91 is, for example, a relay or a control device. A wall portion (not shown) protrudes from the main body 62 so that the latching claws 31 and 32 and the electronic component 91 do not come into contact with the cover 61, and the electronic component 91 is placed on the wall portion.

  The thermistor 51 is provided in a region between the flow path 81 and the terminal accommodating region 82. The thermistor 51 is positioned on the extension in the axial direction of the protrusion 74 provided on the main body 62 of the cover 61. Between the protrusion 74 and the thermistor 51, a rubber sponge 75 that is elastically deformed by the pressing force from the protrusion 74 is provided. The rubber sponge 75 presses the thermistor 51 toward the lid 15 of the battery cell 11. The protrusion 74 and the rubber sponge 75 are pressing parts that press the thermistor 51 against the battery cell 11.

  As shown in FIGS. 7 and 8, the cover 61 is provided at a position where the attachment state of the thermistor 51 can be visually recognized from the confirmation holes 70 and 71. In this embodiment, the attachment state of the thermistor 51 is confirmed by confirming the contact portion between the positioning surface 45 of the base portion 42 and the thermistor 51. For this reason, the confirmation part 73 of the confirmation holes 70 and 71 is provided in the position facing the contact part of the positioning surface 45 and the thermistor 51.

A detection line 52 extends from the thermistor 51, and this detection line 52 is connected to the control device. The control device monitors the temperature of the battery cell 11 with the thermistor 51.
Next, the battery module 10 of this embodiment will be described.

  When the thermistor 51 is attached to the battery module 10, the thermistor 51 is positioned by bringing the thermistor 51 into surface contact with the positioning surface 45, and then the cover 61 is attached to press the thermistor 51 by the protrusion 74 and the rubber sponge 75. At this time, the thermistor 51 may be displaced due to the attachment of the cover 61.

  By providing confirmation holes 70 and 71 in the cover 61 so that the contact portion between the positioning surface 45 and the thermistor 51 can be seen from the outside of the cover 61, when the thermistor 51 is displaced when the cover 61 is attached, I can confirm that. When the thermistor 51 is misaligned, the cover 61 is removed and the thermistor 51 is positioned again. When the thermistor 51 is not displaced, the electronic component 91 is placed on the cover 61. After the cover 61 is attached, the thermistor 51 is pressed by the protrusion 74 and the rubber sponge 75, so that the thermistor 51 is not likely to be misaligned. Even if the confirmation holes 70 and 71 are blocked by the electronic component 91, there is no problem. Few. For this reason, the electronic component 91 can be arranged without considering the positions of the confirmation holes 70 and 71.

  Further, when the gas is discharged from the pressure release valve 17 of the battery cell 11, the gas is discharged to the flow path 81. At this time, if the confirmation holes 70 and 71 and the flow path 81 communicate with each other, the gas leaks from the confirmation holes 70 and 71, and the electronic component 91 disposed on the cover 61 is exposed to the gas. This causes 91 failures. Similarly, if the confirmation holes 70 and 71 and the terminal accommodation region 82 communicate with each other, foreign matter may enter the terminal accommodation region 82 from the confirmation holes 70 and 71 and cause a short circuit.

  By providing the confirmation holes 70 and 71 so as not to communicate with the flow path 81 and the terminal accommodating region 82, gas leakage from the confirmation holes 70 and 71 is suppressed. Further, foreign matter is prevented from entering the terminal accommodating region 82 from the confirmation holes 70 and 71.

  Further, when the gas is discharged into the flow path 81, the internal pressure of the flow path 81 increases and the main body 62 tends to warp in the thickness direction, but the locking claws 31 and 32 are connected to the locking holes 66 to 69 and the confirmation holes 70, The main body 62 is hardly warped by being locked to the edge of the locking portion 72 of 71.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) Since the cover 61 is provided with the confirmation holes 70 and 71, the attachment state of the thermistor 51 can be confirmed even if the thermistor 51 is covered by the cover 61. Therefore, when the thermistor 51 is displaced when the cover 61 is attached, the cover 61 can be removed and the thermistor 51 can be attached again. Therefore, the thermistor 51 is not easily detached from the battery cell 11, and the state where the thermistor 51 is attached to the battery cell 11 is maintained.

  (2) When the positioning surface 45 is provided on the second battery holder 40 and the thermistor 51 is attached, the thermistor 51 and the positioning surface 45 are in contact with each other. For this reason, the attachment state of the thermistor 51 can be confirmed by confirming the contact portion between the thermistor 51 and the positioning surface 45, and the attachment state of the thermistor 51 can be easily confirmed.

  (3) The confirmation portion 73 of the confirmation holes 70 and 71 is provided at a position facing the contact portion between the positioning surface 45 and the thermistor 51. For this reason, the contact state between the positioning surface 45 and the thermistor 51 is easily visible, and the attachment state of the thermistor 51 can be easily confirmed.

  (4) Since the locking claws 31 and 32 are locked to the edges of the locking holes 66 to 69 and the confirmation holes 70 and 71, the direction in which the cover 61 is separated from the battery cell 11 or the parallel arrangement of the battery cells 11. The displacement in the direction is suppressed.

  (5) Since the locking claws 31 and 32 are locked to the edges of the locking holes 66 to 69 and the confirmation holes 70 and 71, the main body 62 is not easily warped even if the internal pressure of the flow path 81 increases. For this reason, it is difficult to form a gap between the partition walls 64 and 65 and the battery cell 11, and the gas is difficult to leak out of the flow path 81.

  (6) The first locking claws 31 and the second locking claws 32 are shifted from each other. For this reason, it is suppressed that the cover 61 is attached in the wrong direction. Since it is suppressed that the cover 61 is attached to an incorrect position, it is suppressed that the confirmation holes 70 and 71 are located in the position where the thermistor 51 cannot be visually recognized.

  (7) A rubber sponge 75 is provided between the protrusion 74 and the thermistor 51, and the thermistor 51 is pressed down by the rubber sponge 75. When the thermistor 51 is pressed, the rubber sponge 75 is elastically deformed. Therefore, even if there is a slight dimensional difference due to the dimensional tolerance of the thermistor 51, the thermistor 51 can be appropriately pressed by the elastic deformation of the rubber sponge 75.

(8) Since the visual recognition portion is the confirmation holes 70 and 71 provided in the cover 61, the visual recognition portion is easily provided in the cover 61.
In addition, you may change embodiment as follows.

  In the embodiment, the attachment state of the thermistor 51 is confirmed by confirming the contact portion between the positioning surface 45 and the thermistor 51. However, from other parts such as whether the thermistor 51 is pressed by the rubber sponge 75 or the like. You may confirm the attachment state of the thermistor 51. FIG.

The confirmation holes 70 and 71 may be provided at any position on the cover 61 as long as the attachment state of the thermistor 51 can be visually recognized.
O The latching claws 31 and 32 may be latched by the confirmation part 73 of the confirmation holes 70 and 71.

  The first locking claw 31 and the second locking claw 32 provided on the first battery holder 20 do not have to be shifted in the axial direction of the column members 26 and 27. 26 and 27 may be provided at the same position in the axial direction.

  ○ When it is not necessary to consider the warpage of the main body 62 of the cover 61, or when the warpage of the main body 62 can be suppressed by other members, the battery holders 20, 40 are not provided with the locking claws 31, 32. May be.

  The confirmation holes 70 and 71 may be provided at positions communicating with the flow path 81 and the terminal accommodating area 82, that is, at the flow path partitioning section and the receiving area partitioning section of the main body 62. In this case, after the cover 61 is attached, it is preferable to check the position shift of the thermistor 51 from the confirmation holes 70, 71 and then close the confirmation holes 70, 71 with the electronic component 91 or the like placed on the cover 61. When the confirmation holes 70 and 71 are in communication with the flow path 81, the electronic component 91 is exposed to the gas discharged to the flow path 81. , 71 are preferably closed. For example, it is possible to suppress the influence of the gas on the electronic component 91 by closing with the substrate constituting the electronic component 91.

-The holding | suppressing part may be provided in the battery holders 20 and 40, etc.
O The thermistor 51 may be directly pressed by the protrusion 74 without providing the rubber sponge 75.

The cover 61 may be configured by connecting a plurality of members.
The thermistor 51 may be attached to the case body 14 of the battery cell 11. In this case, the cover 61 is arranged according to the mounting surface of the thermistor 51.

○ The number of locking holes may be changed as appropriate. Further, the number of confirmation holes may be appropriately changed according to the number of thermistors 51.
The notch provided in the cover 61 may be sufficient as the visual recognition part. Moreover, when the cover 61 is comprised by the several member, the clearance gap etc. which were divided between each member may be sufficient.

The visual recognition part may have a structure in which the confirmation part 73 is closed with a transparent material (glass or the like).
The cover 61 may cover the entire attachment surface 15 a of each battery cell 11. A part of the attachment surface 15 a of each battery cell 11 may not be covered with the cover 61.

  DESCRIPTION OF SYMBOLS 10 ... Battery module, 11 ... Battery cell, 15a ... Mounting surface, 20, 40 ... Battery holder, 31, 32 ... Locking claw, 45 ... Positioning surface, 51 ... Thermistor, 61 ... Cover, 70, 71 ... Confirmation hole, 81... Channel, 82.

Claims (3)

A battery cell;
A thermistor attached to the battery cell;
A battery module provided with a cover that is provided opposite to a mounting surface on which the thermistor of the battery cell is mounted, and covers the mounting surface;
The cover has a visual recognition part that can visually recognize the thermistor when the cover is attached;
The visual recognition part is a confirmation hole penetrating the cover;
The cover has a flow path partition section that partitions a flow path of gas discharged from the battery cell, and a storage area partition section that partitions a terminal storage area in which a terminal of the battery cell is stored,
The thermistor is provided in a region between the flow path and the terminal accommodating region,
The confirmation hole is not that batteries module provided between the passage partition part the accommodating region dividing portion. A battery cell;
A thermistor attached to the battery cell;
A battery module provided with a cover that is provided opposite to a mounting surface on which the thermistor of the battery cell is mounted, and covers the mounting surface;
The cover has a visual recognition part that can visually recognize the thermistor when the cover is attached;
Wherein the cover, the thermistor pressing portion is not that batteries module provided to press the battery cell. A battery cell;
A thermistor attached to the battery cell;
A battery module provided with a cover that is provided opposite to a mounting surface on which the thermistor of the battery cell is mounted, and covers the mounting surface;
The cover has a visual recognition part that can visually recognize the thermistor when the cover is attached;
A battery holder for holding the battery cell, and a positioning surface with which the thermistor contacts;
The visual recognition portion is provided at a position where the contact portion between the positioning surface and the thermistor can be visually recognized.
The visual recognition part is a confirmation hole penetrating the cover;
The battery holder, the module batteries that have a locking claw to prevent the positional displacement of the cover engaged with the edge of the check hole.