Battery pack

Abstract

A battery pack (10) has a temperature detection unit (20) that detects the temperature of a battery cell (34). The temperature detection unit (20) is provided with a first temperature sensor (48) that is attached to a central battery cell (34a) disposed at the center in a first direction among a plurality of battery cells (34), and a second temperature sensor (50) that is attached to an end battery cell (34b) disposed at one end in the first direction among the plurality of battery cells (34). No temperature sensor is attached to an end battery cell (34c) disposed at the other end in the first direction among the plurality of battery cells (34).

Description

Technical Field

[0001] The present invention relates to a battery pack including a temperature detection unit capable of detecting the temperature of a battery cell housed in a case.

Background Art

[0002] The applicant has proposed a battery pack that can be detachably mounted on electric vehicles such as electric assist bicycles and electric motorcycles in Japanese Patent No. 6790176. The battery pack includes a battery core pack having a plurality of battery cells and a case that houses the battery core pack.

[0003] Generally, in a battery pack, a plurality of battery cells are arranged in a battery core pack, and the battery pack includes a temperature sensor capable of detecting the temperature of the battery cells. The temperature sensor detects the maximum temperature and the minimum temperature in the battery core pack. When the temperature in the battery core pack detected by the temperature sensor is likely to exceed a reference temperature, charging of the battery pack is stopped to protect the battery pack.

Summary of the Invention

[0004] In a battery pack having a plurality of battery cells, when detecting the minimum temperature and the maximum temperature of the battery cells, it is necessary to arrange a plurality of temperature sensors according to a plurality of battery cells having different arrangement locations. Preparing a large number of temperature sensors increases the cost.

[0005] An aspect of the present invention is a battery pack including a plurality of battery cells and a case that houses the plurality of battery cells, wherein the plurality of battery cells are arranged in parallel in a first direction that is the axial direction of the case perpendicular to the cell axial direction of the plurality of battery cells, the battery pack having a temperature detection unit that detects the temperature of the battery cells, the temperature detection unit including a first temperature sensor attached to a central battery cell arranged at the center in the first direction among the plurality of battery cells, A second temperature sensor is attached to an end battery cell, which is located at one end of the plurality of battery cells in the first direction, The device is equipped with such a feature, and the battery cell located at the other end in the first direction among the plurality of battery cells does not have a temperature sensor attached to it.

[0006] According to the present invention, the first temperature sensor in the temperature detection unit detects the temperature of the central battery cell among the multiple battery cells, thereby enabling the detection of the highest temperature of the battery pack near the center in the first direction where heat tends to accumulate. The second temperature sensor detects the temperature of the end battery cells among the multiple battery cells, thereby enabling the detection of the lowest temperature of the battery pack near one end in the first direction where heat dissipation is relatively easy. As a result, the highest and lowest temperatures within the battery pack can be detected with a minimum of two first and second temperature sensors, enabling low-cost and effective protection of the battery pack. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is an external perspective view of a battery pack according to an embodiment of the present invention. [Figure 2] Figure 2 is a schematic front view of the battery pack shown in Figure 1, viewed from the front. [Figure 3] Figure 3 is a schematic side view of the battery pack shown in Figure 1, viewed from the side. [Figure 4] Figure 4 is a schematic side view showing a modified battery core pack. [Modes for carrying out the invention]

[0008] As shown in Figure 1, the battery pack 10 according to this embodiment can be applied as a portable battery pack that can be detachably mounted on an electric vehicle (not shown), such as an electric assist bicycle or an electric motorcycle. The battery pack 10 can be applied to various external devices that require power. An example of the battery pack 10 being mounted on an electric vehicle will be described below. The vertical direction of the battery pack 10 is the vertical direction when the battery pack 10 is mounted on an electric vehicle, or a direction inclined with respect to the vertical direction.

[0009] As shown in Figure 1, the battery pack 10 comprises a case 12, first and second battery core packs 14 and 16, a Battery Management Unit (BMU) 18, a temperature detection unit 20 (see Figure 2), and heat dissipation sheets 22a and 22b.

[0010] Case 12 houses first and second battery core packs 14 and 16, each containing multiple battery cells 34, and a battery management device 18. Case 12 has a bottom case 24, an outer shell case 26, and a top case 28. Hereinafter, the axial direction of Case 12 shown in Figure 1 will be referred to as the Z direction or the first direction.

[0011] The bottom case 24 is located at the bottom of the case 12. The bottom case 24 covers the bottom of the first and second battery core packs 14 and 16. The outer shell case 26 is formed hollow from a metal material such as aluminum and is attached to the upper end of the bottom case 24. The outer shell case 26 covers the sides of the first and second battery core packs 14 and 16. The top case 28 is attached to the upper end of the outer shell case 26. The top case 28 covers the top of the first and second battery core packs 14 and 16. The top of the top case 28 is equipped with a handle 30. The handle 30 is gripped by the user when carrying the battery pack 10.

[0012] As shown in Figures 1 and 2, the first and second battery core packs 14 and 16 are formed with substantially the same shape. The first battery core pack 14 and the second battery core pack 16 are connected to each other by a connecting body (not shown) in a direction perpendicular to the axial direction (first direction) of the case 12 (arrow Y direction).

[0013] The first and second battery core packs 14 and 16 each have a plurality of battery cells 34 and a cell holder 38.

[0014] As shown in Figure 2, each battery cell 34 is cylindrical and extends along the cell axis direction (arrow Y direction) perpendicular to the first direction (arrow Z direction) of the case 12. A positive electrode terminal is located at one end of each battery cell 34 along the cell axis direction. A negative electrode terminal is located at the other end of each battery cell 34 along the cell axis direction. The battery cell 34 is, for example, a lithium secondary battery that can be repeatedly charged and discharged.

[0015] The cell holder 38 has multiple insertion holes 44. Viewed from the cell axis direction as shown in Figure 3, the multiple insertion holes 44 are circular in shape. Multiple battery cells 34 are inserted into and held in the multiple insertion holes 44.

[0016] As shown in Figure 3, the cell holder 38 has a first direction row 46 in which seven insertion holes 44 are arranged along a first direction (arrow Z direction), and each insertion hole 44 constituting the first direction row 46 is equally spaced apart along the first direction (arrow Z direction). Multiple first direction rows 46 are arranged in parallel with spacing in a second direction (arrow X direction), which is the width direction of the cell holder 38. Each first direction row 46 is arranged in parallel in the second direction (arrow X direction). Below, an example in which six first direction rows 46 are arranged in the cell holder 38 as shown in Figure 3 will be described.

[0017] Of the six first-direction rows 46, a pair of intermediate rows 46b are positioned adjacent to a pair of end rows 46a located at both ends of the second direction (arrow X direction), offset downward along the first direction. A pair of central rows 46c are positioned adjacent to the pair of intermediate rows 46b in the second direction. The pair of central rows 46c are positioned offset upward along the first direction relative to the intermediate rows 46b. In the first direction, the pair of end rows 46a and the pair of central rows 46c are in the same position. That is, each first-direction row 46 adjacent to the second direction is positioned alternately in the first direction.

[0018] Multiple battery cells 34 are inserted into multiple insertion holes 44, and are arranged in parallel along the first direction of the cell holder 38 at equal intervals from each other (see Figures 2 and 3). Multiple battery cells 34 are also arranged in parallel along the second direction of the cell holder 38 at equal intervals from each other (see Figure 3). The number of battery cells 34 is equal to the number of insertion holes 44.

[0019] As shown in Figure 2, the first battery core pack 14 and the second battery core pack 16 are arranged in parallel in the cell axis direction (arrow Y direction) of the battery cells 34. The number and arrangement of the multiple battery cells 34 in the first battery core pack 14 are the same as those in the second battery core pack 16.

[0020] In each of the first and second battery core packs 14 and 16, the battery cells 34 are connected in parallel and in series by a plurality of busbars 60. The busbars 60 are connected to a battery management device 18, which will be described later, via lead wires. In the first and second battery core packs 14 and 16, the busbars 60 are arranged facing each other on the outer casing case 26. The first battery core pack 14 and the second battery core pack 16 are connected by a busbar 62.

[0021] Note that the plurality of battery cells 34 in the first and second battery core packs 14 and 16 are not limited to the case where the adjacent first-direction columns 46 are arranged alternately in the first direction as shown in FIG. 3. For example, as in the first and second battery core packs 14a and 16a shown in FIG. 4, all the first-direction columns 46d may be arranged at the same position in the first direction in the second direction (arrow X direction), and a plurality of battery cells 34d may be arranged in the insertion holes 44 of the first-direction columns 46d.

[0022] As shown in FIGS. 1 to 3, the battery management device 18 controls the charging and discharging of the first and second battery core packs 14 and 16 and communicates with the electric vehicle. The battery management device 18 is connected to each battery cell 34 of the first and second battery core packs 14 and 16 via a lead wire (not shown). The power of the plurality of battery cells 34 is supplied from the battery management device 18 to the electric vehicle via a connector portion not shown.

[0023] As shown in FIGS. 2 and 3, the temperature detection unit 20 is provided for the purpose of detecting the temperature of some of the plurality of battery cells 34. The temperature detection unit 20 includes a first temperature sensor 48 and a second temperature sensor 50. The first and second temperature sensors 48 and 50 are, for example, thermocouples or the like. The first and second temperature sensors 48 and 50 are respectively connected to the battery management device 18 via lead wires 52.

[0024] The first temperature sensor 48 is arranged in the first battery core pack 14. The first temperature sensor 48 can detect the highest temperature that becomes the highest within the first battery core pack 14. The first temperature sensor 48 is arranged near the center of the first battery core pack 14 in the first and second directions. The vicinity of the center of the first battery core pack 14 is a portion where the heat generated by the plurality of battery cells 34 tends to accumulate and reach the highest temperature.

[0025] The first temperature sensor 48 is attached to the central battery cell 34a. The central battery cell 34a is one battery cell that is arranged at the center in the first direction (arrow Z direction) among the plurality of battery cells 34 and is arranged in the central row 46c that is at the center in the second direction (arrow X direction). When an even number of battery cells 34 are arranged in the first and second directions, the central battery cell 34a is one of the two battery cells 34 arranged near the center in the first direction and one of the two battery cells 34 arranged near the center in the second direction.

[0026] As shown in FIG. 2, the first temperature sensor 48 is arranged at the axial center of the central battery cell 34a in the cell axis direction (arrow Y direction). The first temperature sensor 48 is mounted on the outer peripheral surface 36a of the central battery cell 34a (see FIG. 3). The first temperature sensor 48 is attached to either one of the pair of central battery cells 34a arranged in the pair of central rows 46c.

[0027] The temperature near the center of the first battery core pack 14 can be detected by the first temperature sensor 48 attached to the central battery cell 34a. After the temperature of the central battery cell 34a is detected by the first temperature sensor 48, it is output as a detection signal to the battery management device 18 via the lead wire 52.

[0028] The second temperature sensor 50 is arranged in the second battery core pack 16. The second temperature sensor 50 can detect the lowest temperature that becomes the lowest in the second battery core pack 16. The second temperature sensor 50 is arranged near the ends of the second battery core pack 16 in the first and second directions. The vicinity of the ends of the second battery core pack 16 is a part where the heat generated by the plurality of battery cells 34 is easily radiated to the outside and becomes the lowest temperature.

[0029] The second temperature sensor 50 is attached to the end battery cell 34b. The end battery cell 34b is one of the multiple battery cells 34 of the second battery core pack 16, located at the topmost end in the first direction and positioned in the end row 46a in the second direction. As shown in Figure 2, the second temperature sensor 50 is positioned in the cell axis direction center of the end battery cell 34b. The second temperature sensor 50 is mounted on the outer circumferential surface 36b of the end battery cell 34b (see Figure 3). In the second direction, the second temperature sensor 50 is attached to one of the pair of end battery cells 34b located in the pair of end rows 46a.

[0030] A second temperature sensor 50, mounted on the end battery cell 34b, can detect the temperature near the first and second ends of the second battery core pack 16. After the temperature of the end battery cell 34b is detected by the second temperature sensor 50, it is output as a detection signal to the battery management device 18 via the lead wire 52.

[0031] In this case, the second temperature sensor 50 is not attached to the end battery cell 34c, which is located at the bottom of the multiple battery cells 34 of the second battery core pack 16, and is at the end in the first direction (arrow Z direction).

[0032] Furthermore, the second temperature sensor 50 is not limited to the case where it is attached to the uppermost battery cell 34 (end battery cell 34b) in the first direction. Instead of the end battery cell 34b, the second temperature sensor 50 may be attached to the lowermost battery cell 34 (end battery cell 34c) in the end row 46a.

[0033] In the battery pack 10, there are only two temperature sensors provided to detect the temperature of the battery cells 34: a first temperature sensor 48 and a second temperature sensor 50. The first temperature sensor 48 may be attached to the central battery cell 34a of the second battery core pack 16, and the second temperature sensor 50 may be attached to the end battery cell 34b of the first battery core pack 14. It is sufficient that the first and second temperature sensors 48 and 50 are attached to either the first battery core pack 14 or the second battery core pack 16, respectively. The first and second temperature sensors 48 and 50 may both be attached to the first battery core pack 14. The first and second temperature sensors 48 and 50 may both be attached to the second battery core pack 16.

[0034] As shown in Figures 1 and 2, the heat dissipation sheets 22a and 22b are placed between the first and second battery core packs 14 and 16 and the outer shell case 26, respectively. The heat dissipation sheets 22a and 22b are, for example, sheet-like members having high thermal conductivity.

[0035] As shown in Figure 3, when viewed from the cell axis direction of the battery cell 34, the first dimension of the heat dissipation sheets 22a and 22b along the first direction (arrow Z direction) is greater than or equal to the dimension of the cell group along the first direction, and the second dimension of the heat dissipation sheets 22a and 22b along the second direction (arrow X direction) is greater than or equal to the dimension of the cell group along the second direction. When viewed from the direction shown in Figure 3, the outer edges of the heat dissipation sheets 22a and 22b are positioned outside the cell group. That is, all the battery cells 34 in the first and second battery core packs 14 and 16 are covered by the heat dissipation sheets 22a and 22b, respectively.

[0036] The heat dissipation sheets 22a and 22b are in contact with the inner wall 26a of the outer shell case 26. In the cell axis direction (arrow Y direction) of the battery cell 34, the heat dissipation sheets 22a and 22b are positioned between the inner wall 26a of the outer shell case 26 and the bus bar 60. Heat dissipation sheet 22a is in contact with the bus bar 60 of the first battery core pack 14 in the cell axis direction. Heat dissipation sheet 22b is in contact with the bus bar 60 of the second battery core pack 16 in the cell axis direction. The heat dissipation sheets 22a and 22b are capable of transferring heat generated in the multiple battery cells 34 from the bus bars 60 of the first and second battery core packs 14 and 16 to the outer shell case 26.

[0037] Next, we will describe how to use the battery pack 10. The user holds the handle 30 and carries the battery pack 10 to the vicinity of the charging device, and connects the connector to the charging device. This allows each battery cell 34 to be charged. On the other hand, for example, the battery pack 10, which has been carried by holding the handle 30, can be mounted on an electric vehicle, and each battery cell 34 can be discharged by connecting the connector (not shown) to the power supply port.

[0038] When each battery cell 34 of the first and second battery core packs 14 and 16 is charged or discharged, each battery cell 34 generates heat. The heat from each battery cell 34 of the first and second battery core packs 14 and 16 causes the internal temperature of the case 12 to rise.

[0039] At this time, the temperature of the central battery cell 34a of the first battery core pack 14 is detected by the first temperature sensor 48. The central battery cell 34a is located in the center of the first battery core pack 14 in both the first and second directions, where heat tends to accumulate. Therefore, the temperature detected by the first temperature sensor 48 is the highest temperature of the first battery core pack 14.

[0040] The second temperature sensor 50 detects the temperature of the end battery cells 34b of the second battery core pack 16. The end battery cells 34b are located at the first and second ends of the second battery core pack 16, where heat is relatively easily dissipated. Therefore, the temperature detected by the second temperature sensor 50 is the lowest temperature of the second battery core pack 16.

[0041] The temperatures detected by the first and second temperature sensors 48 and 50 are output as detection signals to the battery management device 18 via the lead wires 52, respectively.

[0042] The operation of the battery pack 10 is controlled based on the highest temperature of the first battery core pack 14 detected by the first temperature sensor 48 and the lowest temperature of the second battery core pack 16 detected by the second temperature sensor 50.

[0043] The battery management device 18 compares a preset temperature with the highest temperature detected by the first temperature sensor 48. When the highest temperature approaches the preset temperature, it protects the battery pack 10 by, for example, stopping the charging of the battery pack 10.

[0044] The heat generated in each battery cell 34 is transferred from the cell-axial end faces of the first and second battery core packs 14 and 16 to the heat dissipation sheets 22a and 22b. The heat is then transferred from the heat dissipation sheets 22a and 22b to the outer casing 26. As a result, the heat generated in each battery cell 34 is dissipated to the outside through the outer casing 26, which is made of metal.

[0045] As described above, in the embodiment of the present invention, the temperature detection unit 20 of the battery pack 10 includes a first temperature sensor 48 attached to a central battery cell 34a located in the center of a plurality of battery cells 34 in a first direction, and a second temperature sensor 50 attached to an end battery cell 34b located at one end of a plurality of battery cells 34 in the first direction.

[0046] As a result, the first temperature sensor 48 detects the temperature of the central battery cell 34a among the multiple battery cells 34, thereby enabling the detection of the highest temperature of the battery pack 10 near the center in the first direction where heat tends to accumulate. The second temperature sensor 50 detects the temperature of the end battery cells 34b among the multiple battery cells 34, thereby enabling the detection of the lowest temperature of the battery pack 10 near one end in the first direction where heat dissipation is relatively easy.

[0047] As a result, the maximum and minimum temperatures inside the battery pack 10 can be detected by a minimum of two first and second temperature sensors 48 and 50, and based on the detected maximum and minimum temperatures, temperature protection of the battery pack 10 can be performed at low cost and effectively.

[0048] In a plurality of battery cells 34 arranged in parallel along the second direction, by placing the first temperature sensor 48 in the central battery cell 34a located in the center along the second direction, the highest temperature near the center of the first battery core pack 14 in the second direction, where the heat from the plurality of battery cells 34 tends to accumulate and become high, can be reliably and effectively detected by a single first temperature sensor 48.

[0049] In the first battery core pack 14, one of the multiple battery cells 34 is the central battery cell 34a on which the first temperature sensor 48 is located, and in the second battery core pack 16, one of the multiple battery cells 34 is the end battery cell 34b on which the second temperature sensor 50 is located.

[0050] This allows the first temperature sensor 48 to detect the highest temperature near the center of the first battery core pack 14, and the second temperature sensor 50 to detect the lowest temperature near the edge of the second battery core pack 16. This makes it possible to achieve temperature detection in the first and second battery core packs 14 and 16 at a lower cost and more effectively.

[0051] By positioning the first temperature sensor 48 in the center of the central battery cell 34a in the cell axis direction, the first temperature sensor 48 can reliably and effectively detect the temperature near the center of the central battery cell 34a in the cell axis direction, where heat tends to accumulate and become high.

[0052] By positioning the second temperature sensor 50 in the center of the cell axis direction of the end battery cell 34b, the temperature near the center of the cell axis direction of the end battery cell 34b can be detected by the second temperature sensor 50, thereby enabling stable detection of the temperature near the end battery cell 34b.

[0053] The outer shell case 26, formed from a metal material, has heat dissipation sheets 22a and 22b that contact the inner wall 26a. The heat dissipation sheets 22a and 22b are arranged in the cell axis direction relative to the inner wall 26a, enabling the heat from multiple battery cells 34 to be transferred to the outer shell case 26.

[0054] As a result, when multiple battery cells 34 generate heat, the heat is transferred from the busbar 60 through the heat dissipation sheets 22a and 22b to the metal outer shell case 26. When there is an uneven distribution of heat generation among the battery cells 34 due to the inherent degradation of each battery cell 34, the outer shell case 26 and the heat dissipation sheets 22a and 22b equalize the temperature variation among the battery cells 34. Therefore, the equalized heat generation (temperature) of the battery cells 34 can be detected by the temperature detection unit 20 (first and second temperature sensors 48 and 50).

[0055] The first temperature sensor 48 is attached to the outer surface 36a of the central battery cell 34a, and the second temperature sensor 50 is attached to the outer surface 36b of the end battery cell 34b. This allows the first and second temperature sensors 48 and 50 to be easily attached to the outer surfaces (36a and 36b) of the battery cells 34 of an existing battery pack. The first and second temperature sensors 48 and 50 can be easily attached to appropriately selected battery cells 34 (central battery cell 34a, end battery cells 34b) from among a plurality of battery cells 34.

[0056] When multiple battery cells 34 generate heat, and there is an imbalance in the amount of heat generated by the battery cells 34 between the first battery core pack 14 and the second battery core pack 16, the heat is transferred to the metal outer shell case 26 through the heat dissipation sheets 22a and 22b, thereby equalizing the temperature variation between the first battery core pack 14 and the second battery core pack 16. As a result, the equalized amount of heat generated (temperature) of the battery cells 34 can be stably detected by the first temperature sensor 48 located in the first battery core pack 14 and the second temperature sensor 50 located in the second battery core pack 16.

[0057] The above embodiments can be summarized as follows:

[0058] The above embodiment is a battery pack (10) comprising a plurality of battery cells (34) and a case (12) housing the plurality of battery cells, wherein the plurality of battery cells are arranged in parallel in a first direction which is perpendicular to the cell axis direction of the plurality of battery cells and is the axis direction of the case, It has a temperature detection unit (20) for detecting the temperature of the battery cell, The temperature detection unit includes a first temperature sensor (48) attached to the central battery cell (34a) which is located in the center of the plurality of battery cells in the first direction, A second temperature sensor (50) is attached to an end battery cell (34b) of the plurality of battery cells, which is located at one end in the first direction, The battery cell (34c) located at the other end in the first direction among the plurality of battery cells does not have a temperature sensor attached.

[0059] Inside the case, a plurality of battery cells are arranged in parallel along the cell axis direction and a second direction perpendicular to the first direction. The central battery cell is a battery cell located in the center of the plurality of battery cells arranged in parallel along the second direction.

[0060] The system comprises a first battery core pack (14) having multiple battery cells and a second battery core pack (16) having multiple battery cells. One of the plurality of battery cells in the first battery core pack is the central battery cell on which the first temperature sensor is located. One of the plurality of battery cells in the second battery core pack is the end battery cell on which the second temperature sensor is located.

[0061] The first temperature sensor is positioned at the center of the central battery cell in the direction of the cell axis.

[0062] The second temperature sensor is positioned at the center of the end battery cell in the direction of the cell axis.

[0063] The battery pack comprises an outer shell case (26) formed from a metal material and constituting a part of the case, A heat dissipation sheet (22a, 22b) that contacts the inner wall (26a) of the outer shell case and transfers heat from the plurality of battery cells arranged in parallel along the first direction and positioned in the cell axis direction relative to the inner wall to the outer shell case, It is equipped with.

[0064] The first temperature sensor is attached to the outer surface (36a) of the central battery cell. The second temperature sensor is attached to the outer circumferential surface (36b) of the end battery cell.

[0065] Furthermore, the present invention is not limited to the disclosure described above, and can take various configurations without departing from the spirit of the invention.

Claims

1. A battery pack (10) comprising a plurality of battery cells (34) and a case (12) housing the plurality of battery cells, wherein the plurality of battery cells are arranged in parallel in a first direction that is perpendicular to the cell axis direction of the plurality of battery cells and is the axis direction of the case, It has a temperature detection unit (20) for detecting the temperature of the battery cell, The temperature detection unit includes a first temperature sensor (48) attached to the central battery cell (34a) which is located in the center of the plurality of battery cells in the first direction, A second temperature sensor (50) is attached to an end battery cell (34b) of the plurality of battery cells, which is located at one end in the first direction, Equipped with, The first battery core pack (14) having the plurality of battery cells, The second battery core pack (16) having the plurality of battery cells, Furthermore, The first temperature sensor is attached to the central battery cell, which is one of the plurality of battery cells in the first battery core pack, and is not attached to the battery cell located at one end in the first direction among the plurality of battery cells in the first battery core pack. The second temperature sensor is attached to the end battery cell, which is one of the plurality of battery cells in the second battery core pack, and the battery cell (34c) located at the other end in the first direction among the plurality of battery cells in the second battery core pack does not have a temperature sensor attached to it. The second battery core pack has a first directional row (46) in which the plurality of battery cells are arranged along the first direction, and a plurality of first directional rows are provided. The first direction row includes an end row (46a) arranged adjacent to the end in the cell axis direction and a second direction perpendicular to the first direction, An intermediate row (46b) is arranged adjacent to the end row in the second direction, It has, The end battery cell is arranged at one end in the first direction of the end row, A battery pack in which each of the plurality of battery cells provided in the intermediate row is offset in the direction of the other end in the first direction relative to each of the plurality of battery cells provided in the end row.

2. In the battery pack according to claim 1, Inside the case, the plurality of battery cells are arranged in parallel along the second direction. The central battery cell is a battery cell located in the center of the plurality of battery cells arranged in parallel along the second direction, in a battery pack.

3. In the battery pack according to claim 1 or 2, A battery pack in which the first temperature sensor is positioned at the center of the central battery cell in the cell axis direction.

4. In the battery pack according to claim 1 or 2, A battery pack in which the second temperature sensor is positioned at the center of the end battery cell in the cell axis direction.

5. In the battery pack according to claim 1 or 2, The battery pack comprises an outer shell case (26) formed from a metal material and constituting a part of the case, A heat dissipation sheet (22a, 22b) that contacts the inner wall (26a) of the outer shell case and transfers heat from the plurality of battery cells arranged in parallel along the first direction and positioned in the cell axis direction relative to the inner wall to the outer shell case, A battery pack equipped with this feature.

6. In the battery pack according to claim 1 or 2, The first temperature sensor is attached to the outer circumferential surface (36a) of the central battery cell. The second temperature sensor is attached to the outer circumferential surface (36b) of the end battery cell in the battery pack.

7. In the battery pack according to claim 1 or 2, The first temperature sensor is not attached to the battery cell located at the other end in the first direction of the battery pack.

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