JP2017010879A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack which reduces temperature differences between battery cells.SOLUTION: A battery pack 100 includes a housing 1, a battery module 2 fixed to an inner surface 1s of the housing 1, and a heat radiation sheet 3 disposed between the battery module 2 and the inner surface 1s. The battery module 2 has a plurality of battery units 10A, 10B and is fixed to the inner surface 1s at one end 2a and the other end 2b. Each battery unit 10A has a cell holder 30A, which holds the battery cells 11, and a heat transfer surface 40s and is arranged at the one end 2a side and the other end 2b side. Each battery unit 10B has a cell holder 30B, which holds the battery cells 11, and a heat transfer surface 40s and is arranged between the battery units 10A. The heat transfer surface 40s of the battery unit 10B protrudes to the inner surface 1s side further than the heat transfer surface 40s of the battery unit 10A.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a battery pack.

  Patent Document 1 describes a battery pack. The battery pack includes a battery module, a case that houses the battery module, and a heat conduction member that is interposed between the battery module and the case. The battery module includes a plurality of battery cells arranged in parallel, and is fixed to a side wall of the case. The side wall of the case is provided with a protruding portion that protrudes inside the case. The protruding portion is formed such that the central portion in the short side direction of the side wall is the thickest and gradually becomes thinner toward the end in the short side direction of the side wall.

JP 2014-192120 A

  In the above battery pack, the battery module is fixed to the side wall of the case via the heat conducting member so that the battery cell located on the innermost side of the battery module faces the central portion of the protruding portion. Thereby, due to the change in the thickness of the protrusion, the portion of the heat conducting member corresponding to the battery cell located inside the battery module becomes relatively thin. As a result, since the heat transfer from the battery cell located inside the battery module to the side wall of the case is relatively high, the temperature difference between the battery cells is reduced. Thus, in the said technical field, reducing the temperature difference between battery cells is desired.

  This invention is made in view of such a situation, and it aims at providing the battery pack which can make the temperature difference between battery cells small.

  In order to solve the above-described problems, a battery pack according to the present invention includes a housing, a battery module housed in the housing and fixed to the inner surface of the housing, and a heat conduction interposed between the battery module and the inner surface. A battery pack comprising: a plurality of first battery units and a plurality of second battery units stacked along a predetermined direction; and a first along the predetermined direction. A restraining member that restrains the battery unit and the second battery unit, and is fixed to the inner surface at one end and the other end in a predetermined direction. The first battery unit holds the battery cell and the first battery cell. 1 and a first heat transfer surface for thermally connecting the battery cell and the housing via the heat conducting member, and arranged on one end side and the other end side, The battery unit includes a battery cell and a second holding the battery cell. And a second heat transfer surface for thermally connecting the battery cell and the housing via the heat conducting member, the first battery unit on one end side and the first on the other end side. The second heat transfer surface is disposed between the battery unit and the inner surface side of the first heat transfer surface.

  Here, in the battery pack configured by fixing the battery module to the inner surface of the housing via the heat conducting member, a reaction force is applied to each battery cell of the battery module from the heat conducting member. At this time, the battery cell relatively far from the fixed portion of the battery module to the housing is likely to be separated from the housing and the heat conducting member due to the reaction force. For this reason, a temperature difference may become large between the battery cell close | similar to the fixed part to the housing | casing of a battery module, and a distant battery cell.

  In the battery pack according to the present invention, the battery module is fixed to the housing at one end and the other end in the state where the heat conducting member is interposed. Moreover, in this battery pack, the 1st battery unit is arrange | positioned at the one end side and other end side of a battery module, and the 2nd battery unit is arrange | positioned among them. That is, the battery cell of the first battery unit is relatively close to the fixed part to the housing of the battery module, and the battery cell of the second battery unit is relatively far from the fixed part. On the other hand, the second heat transfer surface of the second battery unit protrudes further toward the inner surface side of the housing than the first heat transfer surface of the first battery unit. That is, in this battery pack, when the battery module is fixed to the casing, the heat transfer surface of the battery cell relatively far from the fixed portion is closer to the inner surface of the casing. For this reason, it is suppressed that the heat transfer surface of the battery cell relatively far from the fixed part to the housing of the battery module is separated from the housing and the heat conducting member. Therefore, the temperature difference between battery cells can be reduced.

  In the battery pack according to the present invention, the battery cell includes a first surface intersecting with a predetermined direction and a second surface along the predetermined direction, and the first holder has the second surface. The first holder includes a first wall disposed on the second surface, the second holder includes a second wall disposed on the second surface, and the first battery unit is disposed on the first surface. A first heat transfer plate including a first main body portion and a first extension portion extending in a predetermined direction from the first main body portion and disposed on the second surface. The second battery unit includes a second main body portion disposed on the first surface, and a second main body portion disposed on the second surface extending from the second main body portion in a predetermined direction. And a second heat transfer plate including the first extension portion, and the first extension portion is disposed on the second surface via the first wall portion, and the second extension portion is Placed on the second surface through the second wall The first heat transfer surface is a surface opposite to the first wall portion in the first extension portion, and the second heat transfer surface is the second wall portion in the second extension portion. The second wall portion may be thicker than the first wall portion. Thus, by making the thickness of the second wall portion thicker than that of the first wall portion, the second heat transfer surface can be reliably protruded from the first heat transfer surface with a simple configuration. it can.

  In the battery pack according to the present invention, the first holder is provided with a first insertion hole through which a bolt is inserted, and the second holder has a second insertion hole through which the bolt is inserted. It is provided and the distance between the 2nd penetration hole and the 2nd heat transfer surface may be larger than the distance between the 1st heat transfer surface and the 1st penetration hole. Thus, a simple configuration is achieved by making the distance between the second insertion hole and the second heat transfer surface larger than the distance between the first insertion hole and the first heat transfer surface. Thus, the second heat transfer surface can be reliably protruded from the first heat transfer surface.

  In the battery pack according to the present invention, the restraining member includes a pair of end plates disposed at one end and the other end, and an elastic member interposed between the end plate and the first battery unit on the one end side. And the number of first battery units on one end side may be smaller than the number of first battery units on the other end side. Thus, when the elastic member is interposed between the end plate and the first battery unit on one end side of the battery module, the battery cell that is easily separated from the heat conducting member is shifted to one end side. For this reason, if the first battery unit on one end side is relatively reduced and the second battery unit is arranged further to the one end side, the battery cell is suppressed from being separated from the heat conducting member on the one end side. The Therefore, even when the elastic member is provided on the one end side as described above, the temperature difference between the battery cells can be reliably reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the battery pack which can make small the temperature difference between battery cells can be provided.

It is a typical side view of the battery pack which concerns on 1st Embodiment. FIG. 2 is a schematic side view of the battery module shown in FIG. 1. FIG. 3 is an exploded perspective view of the battery unit shown in FIG. 2. It is typical sectional drawing along the IV-IV line of FIG. It is a fragmentary sectional view showing a modification. It is a typical side view of the battery pack which concerns on 2nd Embodiment. FIG. 7 is a schematic side view of the battery module shown in FIG. 6. It is typical sectional drawing along the VIII-VIII line of FIG.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements or corresponding elements may be assigned the same reference numerals, and overlapping descriptions may be omitted. In the following drawings, an orthogonal coordinate system S may be shown.
[First Embodiment]

  FIG. 1 is a schematic side view of the battery pack according to the first embodiment. As shown in FIG. 1, the battery pack 100 according to the first embodiment includes a housing 1, a battery module 2, a heat radiating sheet (heat conducting member) 3, and a fixing member 4. The battery module 2 is accommodated in the housing 1. The battery module 2 is fixed to the inner surface 1 s of the housing 1. The heat dissipation sheet 3 is interposed between the inner surface 1 s of the housing 1 and the battery module 2. The fixing member 4 fixes the battery module 2 to the inner surface 1s of the housing 1 at one end 2a and the other end 2b of the battery module 2 in a predetermined direction (x-axis direction of the orthogonal coordinate system S). That is, the battery module 2 is fixed to the inner surface 1s at one end 2a and the other end 2b in a predetermined direction.

  FIG. 2 is a schematic side view of the battery module shown in FIG. As shown in FIG. 2, the battery module 2 includes a plurality of battery units (first battery units) 10 </ b> A, a plurality of battery units (second battery units) 10 </ b> B, and a restraining member 20. The battery units 10A and 10B are stacked on each other along a predetermined direction. That is, here, the predetermined direction is the stacking direction of the battery units 10A and 10B.

  The battery unit 10 </ b> A is disposed on one end 2 a side and the other end 2 b side of the battery module 2. The number of battery units 10A on the one end 2a side and the number of battery units 10A on the other end 2b side are the same here, for example, four. The battery unit 10B is disposed between the battery unit 10A on the one end 2a side and the battery unit 10A on the other end 2b side. Here, the battery unit 10 </ b> B is disposed at the center of the battery module 2 in a predetermined direction. The number of battery units 10B is five, for example.

  The restraining member 20 restrains the battery units 10A and 10B from each other along a predetermined direction. The restraining member 20 includes a pair of end plates 21 disposed at each of the one end 2a and the other end 2b, and a plurality of fastening members 22 that fasten the end plates 21 to each other. The fastening member 22 includes a bolt 23 and a nut 24. The bolt 23 is inserted through the end plate 21 and the battery units 10 </ b> A and 10 </ b> B so as to be bridged between the pair of end plates 21. The nut 24 is screwed to the bolt 23 to fasten the end plates 21 to each other.

  FIG. 3 is an exploded perspective view of the battery unit shown in FIG. 3A shows the battery unit 10A, and FIG. 3B shows the battery unit 10B. FIG. 4 is a schematic cross-sectional view taken along the line IV-IV in FIG. As shown in FIGS. 2 to 4, the battery unit 10 </ b> A includes a battery cell 11, a cell holder (first holder) 30 </ b> A, a heat transfer plate (first heat transfer plate, second heat transfer plate) 40, and Have.

  The battery cell 11 includes an electrode assembly 12, a case 13 that houses the electrode assembly 12, and a pair of terminals 14 that are electrically connected to the electrodes (each of the positive electrode and the negative electrode) of the electrode assembly 12. doing. The electrode assembly 12 includes a plurality of positive electrodes (not shown) and a negative electrode (not shown), and a separator (not shown) disposed between the positive electrode and the negative electrode. The positive electrode and the negative electrode are alternately stacked via separators along a predetermined direction.

  The case 13 has a rectangular parallelepiped shape. Case 13 includes a pair of side surfaces (second surfaces) 13a and 13b facing each other, a pair of side surfaces (first surfaces) 13c and 13d facing each other, and an upper surface 13e and a bottom surface 13f facing each other. . The side surfaces 13a and 13b are surfaces along a predetermined direction. The side surfaces 13c and 13d are surfaces that intersect in a predetermined direction. The side surfaces 13a and 13b connect the side surface 13c and the side surface 13d to each other. The terminal 14 protrudes from the upper surface 13e.

  The cell holder 30 </ b> A holds the battery cell 11. More specifically, the cell holder 30 </ b> A includes a side wall portion 31 </ b> A (first wall portion) and a side wall portion 32 that face each other, and a back surface portion 33 and a bottom wall portion 34. The side wall portions 31A and 32 have a rectangular plate shape. The back surface portion 33 has a rectangular plate shape, and connects the side wall portion 31A and the side wall portion 32 to each other at one end in the longitudinal direction of the side wall portions 31A and 32. The bottom wall portion 34 has a rectangular plate shape, and connects the side wall portion 31A and the side wall portion 32 to each other at the other end portion in the longitudinal direction of the side wall portions 31A, 32.

  In the cell holder 30 </ b> A, the side wall portions 31 </ b> A and 32, the back surface portion 33, and the bottom wall portion 34 define a rectangular parallelepiped space where the battery cells 11 are fitted. The side wall portions 31A and 32 are arranged on the side surfaces 13a and 13b of the case 13 when the battery cell 11 is fitted in the space portion, respectively. Similarly, the back surface portion 33 is disposed on the side surface 13 d in the vicinity of the top surface 13 e of the case 13. Further, the bottom wall portion 34 is disposed on the bottom surface 13 f of the case 13.

  The back surface portion 33 is provided with a pair of protruding portions 35. The projecting portion 35 has a rectangular parallelepiped shape. The protruding portion 35 extends along a predetermined direction. The protruding portion 35 is disposed on the upper surface 13 e of the case 13 and between the pair of terminals 14 when the battery cell 11 is fitted into the space portion. The protruding portion 35 is formed with an insertion hole (first insertion hole) 36 along the extending direction. The bolt 23 of the restraining member 20 is inserted into the insertion hole 36.

  In addition, a pair of projecting portions 37 are provided at a connection portion between the bottom wall portion 34 and the side wall portions 31 </ b> A and 32. The projecting portion 37 has a rectangular parallelepiped shape. The projecting portion 37 extends along a predetermined direction. The projecting portion 37 is disposed at the end of the bottom surface 13f of the case 13 on the side surfaces 13a and 13b side when the battery cell 11 is fitted in the space portion. The protruding portion 37 is formed with an insertion hole 38 along the extending direction. The bolt 23 of the restraining member 20 is inserted into the insertion hole 38.

  The heat transfer plate 40 includes a rectangular plate-like main body portion (first main body portion and second main body portion) 41 and a rectangular plate-like extension portion (first extension portion and second extension portion). 42. The heat transfer plate 40 is formed in an L-shaped plate shape by the main body portion 41 and the extending portion 42. The main body 41 is disposed on the side surface 13d of the battery cell 11 (case 13). The extending portion 42 extends from the main body portion 41 along a predetermined direction and is disposed on the side surface 13a of the battery cell 11 (case 13). In particular, the extending portion 42 is disposed on the side surface 13a via the side wall portion 31A of the cell holder 30A.

  The heat transfer plate 40 is in contact with the battery cell 11 in the main body portion 41 and is in contact with the heat dissipation sheet 3 on the surface of the extending portion 42 on the side opposite to the side wall portion 31A. That is, the heat transfer plate 40 thermally connects the battery cell 11 and the housing 1. In particular, the surface of the extending portion 42 opposite to the side wall portion 31 </ b> A is a heat transfer surface (first heat transfer surface, second heat connection surface) that thermally connects the battery cell 11 and the housing 1 via a heat conductive member. Heat transfer surface) of 40 s.

  Battery unit 10 </ b> B includes a battery cell 11, a cell holder (second holder) 30 </ b> B, and a heat transfer plate 40. That is, the battery unit 10B is different from the battery unit 10A in that it has a cell holder 30B instead of the cell holder 30A, and is the same as the battery unit 10A in other points. The cell holder 30B is different from the cell holder 30A in that it includes a side wall (second wall) 31B instead of the side wall 31A, and is the same as the cell holder 30A in other points.

  The cell holder 30 </ b> B holds the battery cell 11. The side wall 31B has a rectangular plate shape. In the cell holder 30B, the side wall portions 31B and 32, the back surface portion 33, and the bottom wall portion 34 define a rectangular parallelepiped space where the battery cells 11 are fitted. The side wall portion 31 </ b> B is disposed on the side surface 13 a of the case 13 when the battery cell 11 is fitted in the space portion. The extending part 42 of the heat transfer plate 40 is disposed on the side surface 13a via the side wall part 31B of the cell holder 30B.

  Also here, the heat transfer plate 40 contacts the battery cell 11 in the main body portion 41 and contacts the heat radiating sheet 3 on the surface of the extending portion 42 opposite to the side wall portion 31B. That is, the heat transfer plate 40 thermally connects the battery cell 11 and the housing 1. In particular, the surface of the extending portion 42 opposite to the side wall portion 31B is a heat transfer surface 40s that thermally connects the battery cell 11 and the housing 1 via a heat conductive member.

  Here, the thickness TB of the side wall portion 31B is larger than the thickness TA of the side wall portion 31A. Therefore, the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10B protrudes closer to the inner surface 1s side of the housing 1 than the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10A. In other words, the side wall 31B is such that the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10B protrudes closer to the inner surface 1s side of the housing 1 than the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10A. Furthermore, the side wall portion 31A is thicker. In other words, the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10B is a plane defined by the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10A. Projecting toward the outside of the battery module 2.

  Therefore, as shown in FIG. 1, when the battery module 2 is fixed to the housing 1, the heat radiating sheet 3 is relative to the one end 2 a side and the other end 2 b side of the battery module 2 in which the battery unit 10 </ b> A is disposed. And becomes relatively thin at the center of the battery module 2 where the battery unit 10B is disposed.

  As described above, in the battery pack 100, the battery module 2 is fixed to the housing 1 at the one end 2a and the other end 2b with the heat dissipation sheet 3 interposed. In the battery pack 100, the battery unit 10A is disposed on the one end 2a side and the other end 2b side of the battery module 2, and the battery unit 10B is disposed therebetween. That is, the battery cell 11 of the battery unit 10A is relatively close to the fixed portion of the battery module 2 to the housing 1, and the battery cell 11 of the battery unit 10B is relatively far from the fixed portion.

  On the other hand, the heat transfer surface 40s of the battery unit 10B protrudes to the inner surface 1s side of the housing 1 more than the heat transfer surface 40s of the battery unit 10A. That is, in the battery pack 100, when the battery module 2 is fixed to the casing 1, the heat transfer surface 40s of the battery cell 11 relatively far from the fixing portion is closer to the inner surface 1s of the casing 1. . For this reason, the heat transfer surface 40 s of the battery cell 11 that is relatively far from the fixed portion of the battery module 2 to the housing 1 is suppressed from being separated from the housing 1 and the heat radiating sheet 3. Therefore, the temperature difference between the battery cells 11 can be reduced.

  In the battery pack 100, the thickness TB of the side wall 31B of the cell holder 30B in the battery unit 10B is made thicker than the side wall 31A of the cell holder 30A in the battery unit 10A. Thus, the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10B can be reliably projected to the inner surface 1s side of the housing 1 with respect to the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10A with a simple configuration. it can.

  As shown in FIG. 5 (a), the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10B is made to be closer to the inner surface 1s of the housing 1 than the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10A. When projecting to the side, a plate-like spacer 39 is interposed between the side wall portion 31B and the extending portion 42, and the total thickness TB of the side wall portion 31B and the spacer 39 is thicker than the thickness TA of the side wall portion 31A. May be.

Further, as shown in FIG. 5B, the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10B protrudes closer to the housing 1 than the heat transfer surface 40s of the heat transfer plate 40 in the battery unit 10A. In this case, the thickness TD of the extending portion 42 of the heat transfer plate 40 in the battery unit 10B may be made thicker than the thickness TC of the extending portion 42 of the heat transfer plate 40 in the battery unit 10A. In this case, the entire heat transfer plate 40 of the battery unit 10B may be thickened.
[Second Embodiment]

  FIG. 6 is a schematic side view of the battery pack according to the second embodiment. As shown in FIG. 6, the battery pack 100 </ b> A according to the second embodiment is different from the battery pack 100 in that it includes a battery module 2 </ b> A instead of the battery module 2, and is otherwise similar to the battery pack 100. It is. FIG. 7 is a schematic side view of the battery module shown in FIG. As shown in FIG. 7, the battery module 2A is different from the battery module 2 in that it has a battery unit (second battery unit) 10C instead of the battery unit 10B. It is the same.

  The battery unit 10 </ b> C is stacked along the battery unit 10 </ b> A along a predetermined direction and is restrained by the restraining member 20. The battery unit 10C is disposed between the battery unit 10A on the one end 2a side and the battery unit 10A on the other end 2b side of the battery module 2A in a predetermined direction. Here, the number of battery units 10C is five, for example. The battery unit 10C is different from the battery unit 10A in that it has a cell holder (second holder) 30C instead of the cell holder 30A, and is the same as the battery unit 10A in other points.

  FIG. 8 is a schematic cross-sectional view taken along line VIII-VIII in FIG. As shown in FIG. 8, the cell holder 30 </ b> C is different from the cell holder 30 </ b> A in that it includes a protruding portion 35 </ b> C instead of the protruding portion 35. The protruding portion 35C is provided with an insertion hole (second insertion hole) 36C. Here, the shape of the protruding portion 35C and the insertion hole 36C is the same as that of the protruding portion 35 and the insertion hole 36. On the other hand, the positions where the protruding portions 35C and the insertion holes 36C are provided in the cell holder 30C are different from the positions where the protruding portions 35 and the insertion holes 36 are provided in the cell holder 30A.

  More specifically, the protruding portion 35C and the insertion hole 36C are such that the distance DC between the heat transfer surface 40s and the insertion hole 36C in the battery unit 10C is equal to the distance between the heat transfer surface 40s and the insertion hole 36 in the battery unit 10A. The distance DA is larger than the distance DA. Therefore, when the bolt 23 is inserted into the insertion hole 36 </ b> C together with the insertion hole 36, the heat transfer surface 40 s in the battery unit 10 </ b> C protrudes closer to the inner surface 1 s side of the housing 1 than the heat transfer surface 40 s in the battery unit 10 </ b> A.

  The distance DA between the insertion hole 36 and the heat transfer surface 40s is, for example, the distance between the center line C of the insertion hole 36 and the heat transfer surface 40s. The distance DC between the insertion hole 36C and the heat transfer surface 40s is, for example, the distance between the center line C of the insertion hole 36C and the heat transfer surface 40s. Although not shown here, the protruding portion 37 and the insertion hole 38 on the bottom wall portion 34 side are configured in the same manner.

  Therefore, when the battery units 10A and 10C are collectively restrained by the restraining member 20, the battery unit 10C is shifted to the inner surface 1s side of the housing 1 together with the heat transfer surface 40s. As a result, as shown in FIG. 6, the battery module 2 </ b> A as a whole has a curved shape that protrudes toward the inner surface 1 s side of the housing 1 at the center side as compared to the one end 2 a side and the other end 2 b side. . Further, when the battery module 2A is fixed to the housing 1, the heat dissipation sheet 3 is relatively thick on the one end 2a side and the other end 2b side of the battery module 2 where the battery unit 10A is arranged, and the battery unit 10C is arranged. The battery module 2 is relatively thin at the center.

  As described above, also in the battery pack 100A, the temperature difference between the battery cells 11 can be reduced for the same reason as the battery pack 100. In particular, in the battery pack 100A, the distance DC between the heat transfer surface 40s and the insertion hole 36C in the battery unit 10C is made larger than the distance DA between the heat transfer surface 40s and the insertion hole 36 in the battery unit 10A. ing. For this reason, when the bolt 23 is inserted into the insertion hole 36 </ b> C together with the insertion hole 36, the heat transfer surface 40 s in the battery unit 10 </ b> C protrudes closer to the inner surface 1 s side of the housing 1 than the heat transfer surface 40 s in the battery unit 10 </ b> A. By doing so, the heat transfer surface 40s of the battery unit 10C can be reliably protruded from the heat transfer surface 40s of the battery unit 10A with a simple configuration.

  The above embodiment describes one embodiment of the battery pack according to the present invention. Therefore, the battery pack according to the present invention is not limited to the above-described battery packs 100 and 100A. In the battery pack according to the present invention, the above-described battery packs 100 and 100A can be arbitrarily changed without changing the gist of each claim.

  For example, in order to absorb expansion of the battery cell 11, an elastic member may be provided in the battery modules 2 and 2A. In this case, for example, an elastic member such as rubber or sponge can be interposed between the end plate 21 and the battery unit 10A (battery cell 11) on the one end 2a side of the battery modules 2 and 2A. As described above, when the elastic member is interposed on the one end 2a side of the battery modules 2 and 2A, the battery cell 11 that is easily separated from the heat radiation sheet 3 is shifted to the one end 2a side (that is, the side on which the elastic member is disposed).

  Therefore, in this case, if the battery unit 10A on the one end 2a side is less than the battery unit 10A on the other end 2b side, and the battery units 10B and 10C are arranged further to the one end 2a side, the one end 2a side also becomes more The battery cell 11 is suppressed from being separated from the heat dissipation sheet 3. Therefore, even when an elastic member is provided on the one end 2a side, the temperature difference between the battery cells 11 can be reliably reduced.

  In this case, as an example, if the number of the battery units 10A on the one end 2a side is two and the number of the battery units 10A on the other end 2b side is six, one end can be obtained without changing the number of the battery units 10B and 10C. The battery units 10B and 10C can be arranged so as to be biased toward the 2a side. The number of the battery units 10A described above is merely an example, and the number of the battery units 10A is appropriately determined from the balance of the reaction force distribution from the heat radiation sheet 3 and the distribution of the fixing strength of each part of the battery modules 2 and 2A. Can be set.

  Further, in the battery pack 100A, the battery cells 11 of the battery units 10A and 10C may be directly brought into contact with the heat dissipation sheet 3 without using the heat transfer plate 40. In this case, the heat transfer surface that thermally connects the battery cell 11 and the housing 1 via the heat dissipation sheet 3 can be, for example, the side surface 13 a of each battery cell 11.

  Here, in the said embodiment, the aspect which changes the thickness of the wall part of a cell holder in 1st Embodiment, and protrudes one part heat-transfer surface is demonstrated, The insertion hole of the bolt of a cell holder in 2nd Embodiment The mode of shifting the position of and projecting some heat transfer surfaces has been described. However, these aspects can be employed simultaneously. Moreover, in the said embodiment, like the battery unit 10A and the battery unit 10B, or the battery unit 10A and the battery unit 10C, the protrusion amount to the inner surface 1s of the heat transfer surface 40s (the position of the heat transfer surface 40s with respect to the inner surface 1s) The case where two types of battery units different from each other are used has been described. However, three or more types of battery units with different protrusion amounts of the heat transfer surface 40s may be used.

  About the above embodiment, it adds to the following.

(Appendix 1)
A battery module fixed to an external component (for example, a battery pack housing) at one end and the other end in a predetermined direction,
A plurality of first battery units and a plurality of second battery units stacked along the predetermined direction;
A restraining member that restrains the first battery unit and the second battery unit along the predetermined direction,
The first battery unit includes a battery cell, a first holder for holding the battery cell, and a first heat transfer surface for thermally connecting the battery cell and the external component. And disposed on the one end side and the other end side,
The second battery unit includes the battery cell, a second holder for holding the battery cell, and a second heat transfer surface for thermally connecting the battery cell and the housing. And is disposed between the first battery unit on the one end side and the first battery unit on the other end side,
The second heat transfer surface protrudes to the external component side than the first heat transfer surface,
Battery module.

  DESCRIPTION OF SYMBOLS 1 ... Housing | casing, 1s ... Inner surface, 2, 2A ... Battery module, 2a ... One end, 2b ... Other end, 3 ... Radiation sheet (heat conduction member), 10A ... Battery unit (1st battery unit), 10B, 10C ... battery unit (second battery unit), 11 ... battery cell, 13d ... side surface (first surface), 13a ... side surface (second surface), 20 ... restraining member, 21 ... end plate, 23 ... bolt, 30A ... Cell holder (first holder), 30B, 30C ... Cell holder (second holder), 31A ... Side wall (first wall), 31B ... Side wall (second wall), 36 ... Insertion hole (First insertion hole), 36C ... insertion hole (second insertion hole), 40 ... heat transfer plate (first heat transfer plate, second heat transfer plate), 40s ... heat transfer surface (first Heat transfer surface, second heat transfer surface), 41 ... main body (first main body, second main body) ), 42 ... extending portion (first extending portion, a second extending portion), 100, 100A ... battery pack.

Claims (4)

A housing,
A battery module housed in the housing and fixed to the inner surface of the housing;
A heat conducting member interposed between the battery module and the inner surface;
A battery pack comprising:
The battery module includes a plurality of first battery units and a plurality of second battery units stacked along a predetermined direction, and the first battery unit and the second battery along the predetermined direction. A restraining member that restrains the unit, and is fixed to the inner surface at one end and the other end in the predetermined direction,
The first battery unit includes a battery cell, a first holder for holding the battery cell, and a first for thermally connecting the battery cell and the housing via the heat conducting member. A heat transfer surface, disposed on the one end side and the other end side,
The second battery unit includes a second battery for thermally connecting the battery cell, the second holder for holding the battery cell, and the battery cell and the housing via the heat conducting member. A heat transfer surface, and is disposed between the first battery unit on the one end side and the first battery unit on the other end side,
The second heat transfer surface protrudes closer to the inner surface than the first heat transfer surface.
Battery pack. The battery cell includes a first surface that intersects the predetermined direction, and a second surface along the predetermined direction,
The first holder includes a first wall portion disposed on the second surface,
The second holder includes a second wall portion disposed on the second surface,
The first battery unit is disposed on the second surface extending in the predetermined direction from the first main body portion disposed on the first surface, and the first body portion. A first heat transfer plate including a first extension part,
The second battery unit is disposed on the second surface extending from the second main body portion in the predetermined direction from the second main body portion disposed on the first surface. A second heat transfer plate including a second extension part,
The first extending portion is disposed on the second surface via the first wall portion,
The second extension portion is disposed on the second surface via the second wall portion,
The first heat transfer surface is a surface opposite to the first wall portion in the first extension portion,
The second heat transfer surface is a surface of the second extension portion opposite to the second wall portion,
The second wall is thicker than the first wall,
The battery pack according to claim 1. The first holder is provided with a first insertion hole through which a bolt is inserted,
The second holder is provided with a second insertion hole through which the bolt is inserted,
The distance between the second insertion hole and the second heat transfer surface is greater than the distance between the first heat transfer surface and the first insertion hole.
The battery pack according to claim 1 or 2. The restraining member includes a pair of end plates disposed at the one end and the other end, and an elastic member interposed between the end plate and the first battery unit on the one end side,
The number of the first battery units on the one end side is less than the number of the first battery units on the other end side,
The battery pack according to any one of claims 1 to 3.

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