Assembled battery

Abstract

The present invention provides an assembled battery capable of binding a battery pack without using a side rail that connects a pair of end plates to each other. This assembled battery (1) is provided with: a battery main body (20) having a battery pack (30) in which a plurality of single batteries (31) are stacked, and a pair of end plates (40) disposed at both ends in the stacking direction of the battery pack (30); an installation unit in which the battery main body (20) is installed; and a bracket (50) for fixing the battery main body (20) to the installation part, the bracket (50) holding the battery main body (20) in a state in which the battery main body (20) is pressed in the stacking direction.

Description

Technical Field

[0001] The present invention relates to an assembled battery. Background Art

[0002] For example, a battery pack structure is known in which a stacked battery cell group sandwiched by a pair of end plates is fastened together with side rails. The side rails extend along the stacking direction of the stacked battery cell group and have a high rigidity structure capable of withstanding the fastening force. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-73518 Patent Document 2: Japanese Patent Application Publication No. 2017-76504 Patent Document 3: WO2013 / 038520 Summary of the invention Problem that the invention aims to solve

[0004] However, if side rails with high rigidity are used to secure the stacked battery cell group, this may lead to high cost and high weight.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an assembled battery in which a stacked battery cell group is fixed without using side rails. Technical means of solving problems

[0006] The assembled battery of the present invention which solves the above-mentioned problems comprises: A battery body having a battery pack in which a plurality of single cells are stacked and a pair of end plates arranged at both ends of the battery pack in a stacking direction; A setting part on which the battery main body is set; and a fixing member that fixes the battery body to the installation portion, The assembled battery is characterized in that The fixing member holds the battery body in a state where the battery body is pressed in a stacking direction of the battery pack. Effects of the Invention

[0007] According to the present invention, the battery body is held in a state of being pressed in the stacking direction of the battery pack by fixing the battery body to the fixing member on the installation portion, so there is no need to separately provide a fixing member such as a conventional side rail. Therefore, the material of the components can be reduced, and the cost and weight can be reduced.

[0008] Further features related to the present invention will become apparent from the description of this specification and the accompanying drawings. In addition, other problems, structures and effects than those described above will become clear from the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is an overall perspective view of the battery assembly according to the first embodiment. Figure 2 It is a perspective view showing a battery main body of the assembled battery according to the first embodiment. Figure 3 yes Figure 2 Exploded three-dimensional diagram. Figure 4 It is a perspective view showing an example of the bracket according to the first embodiment. Figure 5 It is a diagram for explaining the manufacturing process of the assembled battery according to the first embodiment. Figure 6 It is a perspective view showing a battery main body of the battery pack according to the second embodiment. DETAILED DESCRIPTION

[0010] Next, embodiments of the present invention will be described.

[0011] (First Embodiment) Figure 1 is an overall perspective view of the assembled battery according to the first embodiment, Figure 2 is a perspective view showing a battery main body of the assembled battery according to the first embodiment, Figure 3 yes Figure 2 The exploded perspective view of the assembled battery shown in FIG. Figure 4 1 is a perspective view showing an example of a bracket related to the first embodiment. Figure 1 In the figure, a part of the outer casing is omitted and the interior of the outer casing is partially shown. In addition, for convenience, the height direction, width direction, and thickness direction of the single cell 31 are described as the up-down direction, the left-right direction, and the front-back direction, respectively, but the actual installation posture of the assembled battery 1 is not limited.

[0012] The assembled battery 1 is used as a power source mounted on an electric vehicle, for example, to supply electric power to a running motor. Figure 1 As shown, the assembled battery 1 includes an exterior body 10 and a plurality of battery main bodies 20 housed inside the exterior body 10. The battery main bodies 20 are disposed on a mounting portion (the bottom plate portion 13 of the exterior body 10 in this embodiment).

[0013] The outer casing 10 is formed into a box shape using a thin steel plate such as iron having high rigidity, and has a substantially rectangular bottom plate portion 13, four substantially rectangular vertical plate portions 12 vertically rising from the sides of the bottom plate portion 13, and a substantially rectangular top plate portion 11 disposed opposite the bottom plate portion 13. The outer casing 10 has a storage space inside which a plurality of battery bodies 20 are arranged in parallel.

[0014] The bottom plate 13 preferably has a portion where the battery body 20 is provided with a higher rigidity than the surrounding portion. For example, the portion where the battery body 20 is provided may be thicker than the surrounding portion, or a reinforcing plate may be provided on a fixing portion that fixes the battery body 20 (for example, a fixing portion of the bottom plate 13 that fixes the bracket 50 described later).

[0015] In addition, in the case where the bottom plate portion 13 is wider than the battery body 20, the rigidity of the portion of the bottom plate portion 13 that fixes the battery body 20 may be higher than the surrounding portion. The plate thickness of the area including the fixing portion that fixes the battery body 20 may be thicker than the area outside thereof, or a reinforcing plate may be provided in the area including the fixing portion that fixes the battery body 20.

[0016] like Figure 3 As shown, the battery body 20 includes a battery pack 30 which is a stacked battery cell group in which a plurality of single cells 31 are stacked with spacers interposed therebetween, and a pair of end plates 40 which are disposed at both ends of the battery pack 30 in the stacking direction.

[0017] The battery pack 30 is formed by stacking a plurality of cells 31 in the thickness direction with a resin spacer (not shown) sandwiched between adjacent cells 31. The cell 31 is a square lithium-ion secondary battery having a pair of wide faces facing each other, and has positive and negative electrode terminals 32 arranged at positions separated at both ends of the cover in the left-right direction, and a cleavage valve 33 that cleaves to release gas as the internal pressure of the cell 31 increases is arranged at the center of the cover in the left-right direction. In the battery pack 30, a plurality of cells 31 are stacked in such a manner that the positive and negative electrodes of the electrode terminals 32 are alternately arranged in the stacking direction.

[0018] In the battery body 20, a gas duct 60 as a gas discharge portion is arranged at a position opposite to the cover portion of each single cell 31. The gas duct 60 is a conduction path for discharging the gas released from the cleavage valve 33 to the outside, and extends in the stacking direction of the battery pack 30 at the upper part of the battery body 20. Both ends of the gas duct 60 are bolted to one end plate 40 and the other end plate 40, respectively. The gas duct 60 also functions as a reinforcing member for bearing the binding load of the battery pack 30.

[0019] In the battery pack 30, the left and right sides of the single cells 31 are not closed by the side rails as in the past, but are exposed, which can improve the cooling efficiency of the single cells 31. In this embodiment, the left and right sides of the single cells 31 of the battery pack 30 are exposed to the inner surface (internal space) of the outer casing 10.

[0020] A pair of end plates 40 clamp the battery pack 30 from both sides in the stacking direction, and transmit the fixing load to the battery pack 30. The end plate 40 is composed of a metal block member having a size substantially the same as that of the single cell 31. The end plate 40 has an inner surface that abuts against the wide surface of the single cell 31 at the end of the battery pack 30 in the stacking direction, and an outer surface that is located on the opposite side of the inner surface and exposed toward the outside in the stacking direction. Bolt holes 42 for fixing the end plate 40 to the bracket 50 are provided on the outer surface 41 of the end plate 40. The bolt holes 42 are respectively provided at positions separated on both sides in the width direction of the end plate 40, the width direction of the end plate 40 being a direction orthogonal to the stacking direction of the battery pack 30, and are formed on the end plate 40 along the stacking direction of the battery pack 30 (it may also be a through hole).

[0021] The battery body 20 having the above-described structure is integrally fixed to the exterior body 10 by a bracket 50 as a fixing member. The bracket 50 has a structure that holds the battery pack 30 in a state of being pressed in the stacking direction and fixes the battery body 20 to the exterior body 10. In the following description, the bracket 50 may be referred to as 50A, 50B, 50Aa, 50Ab, 50Ba, and 50Bb.

[0022] The bracket 50 is fixed to a fixing portion formed in advance on the bottom plate portion 13 of the outer casing 10, and plays a role in maintaining the fixing load applied to the battery pack 30 via the end plate 40. Figure 2 As shown, the brackets 50 are provided at positions (50A, 50B) separated from each other on one side and the other side in the stacking direction of the battery pack 30, and the battery pack 30 is inserted between these brackets 50A and 50B in a state where it is pressurized in the stacking direction, and the two ends of the battery body 20 in the stacking direction are fixed. The brackets 50A and 50B are provided at positions with a gap wider than the overall length of the battery body 20 when the battery body 20 is pressurized in the stacking direction, and a gap shorter than the overall length of the battery body 20 when it is not pressurized.

[0023] The bracket 50A and the bracket 50B are arranged at positions separated from each other on both sides of the end plate 40 in the lateral direction, and are arranged at the four corners of the battery body 20. The bracket 50A includes a bracket 50Aa arranged opposite to the end of one side in the lateral direction of the end plate 40, and a bracket 50Ab arranged opposite to the end of the other side in the lateral direction of the end plate 40. In addition, the bracket 50B includes a bracket 50Ba arranged opposite to the end of one side in the lateral direction of the end plate 40, and a bracket 50Bb arranged opposite to the end of the other side in the lateral direction of the end plate 40.

[0024] Brackets 50Aa, 50Ab, 50Ba, and 50Bb are disposed at the ends of the battery body 20 and along four sides extending in the height direction of the battery body 20. Brackets 50Aa and 50Ab, and brackets 50Ba and 50Bb are disposed separately from each other on both sides in the width direction of the end plate 40, so that the center portion of the end plate 40 is exposed.

[0025] The bracket 50 is assembled, for example, by bending a steel plate three-dimensionally and partially welding it, or by welding a plurality of steel plate members to each other. Figure 4 As shown, the bracket 50 includes: a first thin plate portion 51, which extends along the height direction of the battery body 20, is opposite to the end plate 40 and abuts against the outer surface 41; a second thin plate portion 52, which is bent at the lower end of the first thin plate portion 51 and is arranged and fixed along the bottom plate portion 13 of the outer body 10; a third thin plate portion 53, which is arranged perpendicular to the first thin plate portion 51 and the second thin plate portion 52 and is joined to the side surface of the plate; and a top plate 54, which connects the upper end of the first thin plate portion 51 and the upper end of the third thin plate portion 53, and is arranged parallel to the second thin plate portion 52.

[0026] The first thin plate portion 51 is provided with a through hole 51a at a position communicating with the bolt hole 42 of the end plate 40. The end plate 40 can be fixed to the bracket 50 by inserting a bolt from the through hole 51a of the first thin plate portion 51 into the bolt hole 42 of the end plate 40 and tightening the bolt. The bracket 50 is fixed to the exterior body 10 by welding or bolting the second thin plate portion 52 to the bottom plate portion 13 of the exterior body 10. The fastening direction of the bracket 50 and the end plate 40 is the same as the stacking direction of the battery pack 30.

[0027] The base end of the bracket 50 is fixed to the bottom plate 13 of the outer body 10, and the top end is a free end, and has a cantilever support column structure that bears the fixed load of the battery pack 30 over the entire length. The third thin plate portion 53 of the bracket 50 is arranged perpendicularly to the outer surface 41 of the end plate 40, and serves as a reinforcing rib that strengthens the rigidity of the first thin plate portion 51.

[0028] In addition, in the present embodiment, an example of the assembled battery 1 is described in which the battery pack 30 is arranged in such a manner that the surface on the opposite side to the surface of the single cell 31 having the electrode terminal 32 faces the bottom plate portion 13 as the installation portion. Although not shown in the figure, the relationship between the battery pack 30 and the bottom plate portion 13 may be set to be reversed up and down. For example, the battery pack 30 is arranged in such a manner that the surface of the single cell 31 having the electrode terminal 32 faces the bottom plate portion 13 as the installation portion where the battery pack 30 is installed. As a result, it is easy to arrange the heat exchange member (preferably having a cooling or heating function) facing the surface on the opposite side to the surface having the electrode terminal 32. When using a high-power single cell 31, such a reversed configuration is preferably used.

[0029] Figure 5 It is a diagram for explaining the assembly process of the battery pack according to the present embodiment. The assembled battery 1 is assembled through the following steps.

[0030] Step S1: The battery body 20 is formed by placing the end plates 40 at both ends of the battery pack 30 in the stacking direction, and the battery body 20 is pressed in the stacking direction using a jig. The battery body 20 is elastically deformed by the jig pressure and contracts in the stacking direction of the battery pack 30.

[0031] Step S2: The battery body 20 maintained in a pressurized state is inserted between a pair of brackets 50A and 50B separated and opposed to each other in the stacking direction. Here, the brackets 50Aa and 50Ab, and the brackets 50Ba and 50Bb are separated from each other on both sides in the width direction of the end plate 40, so that the central part of the end plate 40 is exposed, so that the jig that has already pressurized the battery body 20 in the stacking direction can be inserted into the central part of the end plate 40, and can be inserted between the brackets 50A and 50B in a state where the battery body 20 is already pressurized.

[0032] Step S3: Remove the clamp to release the pressure on the battery body 20 . The battery body 20 has the following size shape: in the unpressurized state, the length in the stacking direction is longer than the separation interval in the stacking direction of the pair of brackets 50A and 50B, and in the pressurized state, the length in the stacking direction is shorter than the separation interval in the stacking direction of the pair of brackets 50A and 50B due to elastic deformation. Therefore, when the battery body 20 held in a pressurized state is inserted and arranged between the pair of brackets 50 and the pressurization of the clamp is released, the battery body 20 will be restored to its original size before the pressurization from the state of contraction in the stacking direction due to elastic deformation, but it cannot be restored to its original size before the pressurization, and is maintained in a pressurized state between the pair of brackets 50. That is, the battery body 20 is fixed by the pair of brackets 50 at a predetermined fixing load. In addition, it is also possible to insert a spacer for thickness adjustment between the battery body 20 and the brackets 50A and 50B to adjust the length in the stacking direction of the battery pack 30, and to hold the battery body 20 between the pair of brackets 50A and 50B at a desired pressurization load.

[0033] Step S4: Fasten the end plate 40 and the bracket 50 with bolts. Thus, the battery body 20 is fixed to the bottom plate 13 of the exterior body 10 via the pair of brackets 50A and 50B, and is held in a state of being pressed in the stacking direction by the rigidity of the exterior body 10 .

[0034] According to the assembled battery 1 of the present embodiment, the battery body 20 is maintained in a state of being pressurized in the stacking direction between a pair of brackets 50A and 50B fixed to the outer body 10. The fixing load borne by the pair of brackets 50A and 50B from the battery body 20 is supported by the outer body 10. Therefore, there is no need to separately provide a dedicated component such as a side rail that connects a pair of end plates 40 and fixes the battery body 20 as in the prior art. Therefore, it is possible to reduce component materials, and it is possible to achieve low cost and low weight. As an example, the bracket 50 is 70% of the component material used for the side rail. By omitting the side rail, a 30% cost reduction and light weight can be achieved.

[0035] In addition, in the present embodiment, by dividing a pair of brackets 50A, 50B into one side and the other side in the width direction of the end plate 40, the pair of brackets 50A, 50B are made into bracket 50Aa and bracket 50Ab, and bracket 50Ba and bracket 50Bb, thereby facilitating the manufacture of the bracket 50. In addition, it is easy to achieve the accuracy of the position relative to the bottom plate portion 13 of the outer body 10, and it can be configured with high precision.

[0036] In addition, in the above embodiment, although the method in which the pair of brackets 50 are fixed to the bottom plate portion 13 of the outer body 10 in advance through steps S2 and S3, the battery body 20 pressurized in the stacking direction is inserted between the pair of brackets 50 and fixed to the pair of brackets 50, it is also possible to fix it by other methods. For example, instead of steps S2 and S3, the following method may be adopted: the battery body 20 is pressed and pressed from the other side in the stacking direction to the bracket 50A on one side in the stacking direction, and in this state, the bracket 50B on the other side in the stacking direction is fixed to the bottom plate portion 13 of the outer body 10.

[0037] In addition, in this structure, the end plate 40 is fixed to the bracket 50, and the bracket 50 is fixed to the fixing portion of the bottom plate 13. In this structure, since the end plate 40 is not fixed to the bottom plate 13, the structure of the end plate 40 can be simplified and the manufacturability can be improved. As another structure, both the end plate 40 and the bracket 50 can be fixed to the fixing portion of the bottom plate 13, thereby stably fixing the battery body 20 to the bottom plate 13.

[0038] The width of the bracket 50 in the battery stacking direction is formed so that the base end side opposite to the bottom plate portion 13 is wider than the top end side of the bottom plate portion 13 away from the bracket 50. That is, the bracket 50 is formed so that the width in the battery stacking direction becomes wider as it goes from the top end to the base end. By making the width of the bracket in the battery stacking direction wider than the top end, the load of the fixed single battery 31 can be stably supported. For example, the width of the bracket 50 in the battery stacking direction at the base end arranged on the bottom plate portion 13 side is set to a size of more than twice the width of the top end protruding from the bottom plate portion 13 in the battery stacking direction. In this way, the battery pack 30 can be stably fixed to the bottom plate portion 13.

[0039] Since the assembled battery 1 of this embodiment does not have side rails connecting the end plates like the conventional structure, the following advantages are preferable. First, the side surfaces (surfaces in a direction perpendicular to the placement direction) of the stacked single cells 31 face the outer casing 10 on which the battery body 20 is placed, or the space within the outer casing 10. That is, they face not the components of the battery body 20, but the components surrounding the battery body 20. For example, when the side wall of the outer casing 10 or another adjacent battery body 20 is arranged, they face the battery body 20.

[0040] When there are side rails connecting the end plates as in the past, the side surfaces of the single cells are shielded from the internal space of the exterior body 10. In the present embodiment, since there are no structural components of the battery body 20 itself that shield the side surfaces of the single cells 31, this is preferable from the viewpoint of heat dissipation of the single cells 31. In addition, since there are no structural components such as side rails disposed adjacently and oppositely on the side surfaces of the single cells 31, the influence of water droplets such as condensation on the structural components on the single cells 31 can be suppressed.

[0041] In the present embodiment, the bracket 50 is provided on the end plate 40 to apply a fixing force to the stacked single cells 31, but it is also possible to make the end plate 40 and the bracket 50 into an integral structure. In this case, the structure of the end plate 40 is set as follows: in the placement direction of the end plate 40, the width of the base end on the bottom plate 13 side in the battery stacking direction is twice or more of the width of the top end away from the bottom plate 13 side in the battery stacking direction.

[0042] Thus, the battery pack 30 can be stably fixed to the bottom plate 13. In this case, the manufacturing method described above needs to be changed. For example, it is conceivable to sandwich the stacked cells 31 with a member having an integral structure of the end plate 40 and the bracket 50, and fix them to the bottom plate 13 while applying a fixing force.

[0043] In this embodiment, the fixing force of the stacked cells 31 is applied with a load that can achieve a fixing effect, for example, preferably 3 kilonewtons [kN] or more, and preferably 7 kilonewtons [kN] or less.

[0044] In addition, in the present embodiment, the case where the gas duct 60 functions as a reinforcing member for bearing the fixing load of the battery pack 30 is described, but the fixing load is mainly applied by the bracket 50. Therefore, it is also possible to consider the case where the gas duct 60 does not function as a reinforcing member for bearing the fixing load of the battery pack 30. The fixing load is basically applied by the bracket 50. In the case where the end plate 40 has a fixing portion with the bottom plate portion 13, the end plate 40 can also play a fixing role. Thereby, the degree of freedom in design such as making the gas duct 60 lightweight can be improved. In addition, in the present embodiment, the structure in which the battery main body 20 is housed in the outer body 10, that is, the structure in which the battery main body 20 is provided as the outer body 10 is described as an example, but as an alternative to the outer body 10, it is also possible to use only a bottom plate equivalent to the bottom plate portion 13 and provide the battery main body 20 on the bottom plate.

[0045] (Second Embodiment) Next, use Figure 6 The second embodiment of the present invention will be described. Note that the same components as those of the first embodiment are given the same reference numerals and their detailed descriptions are omitted.

[0046] The present embodiment is characterized in that the left and right brackets 50Aa and 50Ab, and the brackets 50Ba and 50Bb, which are separated in the width direction orthogonal to the stacking direction in the first embodiment, are connected to each other to form an integrated structure.

[0047] The bracket 50A has an integral structure in which the third thin plate portion 53 of the bracket 50Aa and the third thin plate portion 53 of the bracket 50Ab adjacent in the width direction are connected by the fourth thin plate portion 55. Therefore, the material of components can be reduced, and the manufacturing cost can be reduced by simplifying the assembly work.

[0048] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the gist of the present invention described in the claims. Explanation of symbols

[0049] 10…external body, 13…bottom plate portion, 20…battery body, 30…battery pack, 31…single cell, 32…electrode terminal, 40…end plate, 42…bolt hole, 50, 50A, 50B, 50Aa, 50Ab, 50Ba, 50Bb…bracket, 51…first thin plate portion, 52…second thin plate portion, 53…third thin plate portion, 60…gas duct (gas exhaust portion).

Claims

1. A battery pack, characterized in that: have: A battery body having a battery pack in which a plurality of single cells are stacked and a pair of end plates arranged at both ends of the battery pack in a stacking direction; A setting part on which the battery main body is set; and a fixing member that fixes the battery body to the installation portion, The fixing member holds the battery body in a state where it is pressed in a stacking direction of the battery pack.

2. The assembled battery according to claim 1, characterized in that: The fixing member includes a pair of brackets disposed opposite to each other at an end portion on one side in the stacking direction of the battery body and an end portion on the other side in the stacking direction. The pair of brackets are arranged with a gap wider than the entire length of the battery body in a state where the battery body is pressurized in the stacking direction, and with a gap shorter than the entire length of the battery body in a state where no pressurization is applied.

3. The assembled battery according to claim 2, characterized in that: The fastening direction of the end plate and the bracket is the same as the stacking direction.

4. The assembled battery according to claim 3, characterized in that: The bracket is fastened to both ends of the battery body in the stacking direction.

5. The assembled battery according to claim 4, characterized in that: The brackets are arranged opposite to the ends of the battery main body in the stacking direction and at positions of the four sides extending in the height direction of the battery main body.

6. The assembled battery according to claim 5, characterized in that: The bracket at least comprises: a first thin plate portion extending along a height direction of the battery body and having a fastening portion fastened to the end plate; A second thin plate portion extending from an end edge of the first thin plate portion along the setting portion and fixed to the setting portion; and The third thin plate portion is arranged perpendicularly to the first thin plate portion and the second thin plate portion and joins the plate side surfaces.

7. The assembled battery according to claim 1, characterized in that: A gas discharge portion extending in the stacking direction is provided on the upper portion of the battery body. Both ends of the gas discharge portion are fastened to the pair of end plates.

8. The assembled battery according to claim 1, characterized in that: The side surfaces of the single cells of the battery pack are exposed to the outside of the battery body.

9. The assembled battery according to claim 1, characterized in that: The assembled battery has an outer casing that accommodates the battery body. The side surfaces of the single cells of the battery pack are exposed to the inner surface of the outer casing.

Images