Battery pack

Abstract

To couple an electrode tab of a single cell and a bus bar to each other to regulate the misalignment at the time of collision input.SOLUTION: A plurality of single cells 110 each having a positive electrode tab 112P protruding outward from the side where the film of an exterior body housing a power generation element is heat-sealed are held by a spacer 120. The spacer 120 is provided with a first bus bar 122P on the positive electrode side, and the first bus bar 122P is electrically connected to the positive electrode tab 112P. A position regulating protrusion 122d is provided on the first bus bar 122P on the positive electrode side, and a position regulating hole 113 is provided on the positive electrode tab 112P. The position-regulating protrusion 122d penetrate the position regulating hole 113 to form a position regulating structure, and are mechanically engaged with each other.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a battery pack having a plurality of stacked single cells.

Background Art

[0002] Conventionally, a battery pack in which thin single cells having a rectangular shape in plan view are stacked is known (for example, Patent Document 1). The single cell of Patent Document 1 has an exterior body (accommodating portion) in which laminate films are folded and the periphery is heat-sealed, and a power generation element is accommodated in this exterior body. An electrode tab connected to the power generation element protrudes to the outside from the heat-sealed side of the accommodating portion. The electrode tab is supported by a spacer attached to the exterior body. A plurality of single cells are stacked together with the spacers, and are assembled by inserting through bolts into the spacers.

[0003] A bus bar is welded to the electrode tab supported by the spacer. The single cells are electrically connected to each other via this bus bar to form a battery pack.

[0004] Such a battery pack is fastened and fixed to a structure (vehicle body frame) of a moving body such as a vehicle. Due to a collision input acting on the structure when the moving body collides with a surrounding object, a force causing relative displacement between the battery pack and the structure acts on the battery pack, and a force causing relative displacement between the single cell and the spacer acts on the single cell. In the single cell disclosed in Patent Document 1, a pair of holes are provided at predetermined intervals in the heat-sealed side where the electrode tab protrudes, and the spacer is provided with a corresponding pair of protrusions. By engaging the protrusions with the holes to integrate the single cell and the spacer, relative displacement between the single cell and the spacer at the time of a collision input is restricted.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the configuration of Patent Document 1, the electrode tabs protrude outward from the heat-sealed side of the exterior body. In a single cell with a short length of the side where the electrode tabs are provided (for example, a single cell with a small capacity), if a pair of holes are provided in the heat-sealed side, the heat-sealing performance may deteriorate.

Means for Solving the Problem

[0007] The assembled battery according to the present invention includes a power generation element covered with a film-shaped exterior body, and a plurality of single cells having a positive electrode tab and a negative electrode tab that are connected to the power generation element and protrude outward from the side where the film of the exterior body is heat-sealed, a plurality of spacers that support the plurality of single cells, a first bus bar on the positive electrode side that is provided on the spacer and electrically connected to the positive electrode tab, and a first bus bar on the negative electrode side that is electrically connected to the negative electrode tab, and at least one of an engagement structure on the positive electrode side that mechanically engages the first bus bar or spacer on the positive electrode side with the positive electrode tab, and an engagement structure on the negative electrode side that mechanically engages the first bus bar or spacer on the negative electrode side with the negative electrode tab. The plurality of single cells and the plurality of spacers are laminated.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0009] - First Embodiment - The assembled battery 100 of the first embodiment will be described with reference to FIGS. 1 to 9. In FIGS. 1 to 9, the same elements are denoted by the same reference numerals, and duplicate descriptions are omitted. In FIGS. 1 to 9, the X-axis intersects the stacking direction of the single battery 110 and indicates a direction along the short side direction of the single battery 110. The Y-axis indicates a direction along the stacking direction of the single battery 110, and the Z-axis intersects the stacking direction of the single battery 110 and indicates a direction along the longitudinal direction of the single battery 110.

[0010] (Assembled battery) FIG. 1 is an overall perspective view of the assembled battery 100 according to the first embodiment, and FIG. 2 is an exploded perspective view of the assembled battery 100. The basic components of the assembled battery 100 mainly include a single battery (cell) 110 shown in FIG. 3, a single battery unit 115 configured to support the single battery 110 with a pair of spacers 120 as shown in FIG. 4, first bus bars 122P and 122N, and a second bus bar 130. The assembled battery 100 includes a single battery group 150 which is an assembly of a plurality of stacked single battery units 115, and bus bar holders 130A and 130B that hold the second bus bars 130, 131P, and 131N disposed on both sides of the single battery group 150.

[0011] The single battery group 150 is sandwiched between two end plates 101 with a plurality of single battery units 115 arranged at both ends in the stacking direction and a single intermediate plate 102 in the middle, and a plurality of spacers 120 are tightened at the four corners of the two end plates 101 with a fastening member 103 composed of four through bolts 103a and nuts 103b for assembly. The assembled battery 100 is installed on a vehicle with bolts (not shown) at vehicle attachment portions 101a provided at three locations on the end plate 101. The detailed description of the battery pack 100 will be described later with reference to the exploded perspective view of FIG. 2. Note that a plurality of single cells 110 are stacked with an elastic sheet or an adhesive interposed between the vertically adjacent single cells 110.

[0012] (Single cell) As shown in FIG. 3, the single cell 110 has a rectangular shape in plan view, with the longitudinal direction along the Z-axis, the short-side direction along the X-axis, and the thickness direction along the Y-axis. The single cell 110 includes an exterior body 111 that houses a power generation element therein, and positive and negative electrode tabs 112P and 112N that protrude in the direction along the Z-axis from a pair of opposing short sides 111a and 111b of the exterior body 111. The exterior body 111 is a housing portion formed by folding a laminate film and heat-sealing four sides 111a to 111d, and the power generation element is housed in the exterior body 111. Electrode tabs 112P and 112N, which serve as input / output terminals for the charge / discharge current to the power generation element, protrude outside from the heat-sealed sides 111a and 111b of the exterior body 111. A pair of position-regulating holes 113 are provided in the electrode tabs 112P and 112N at a predetermined interval in the X-axis direction. As will be described later, the electrode tabs 112P and 112N are laser-welded to first bus bars 122P and 122N (see FIGS. 4 and 5) attached to spacers 120P and 120N. Reference numeral 114 in FIG. 3 indicates the joining position, but no marks are pre-formed on the electrode tabs 112P and 112. That is, between the position-regulating holes 113, the electrode tabs 112P and 112N are laser-welded to the first bus bars 122P and 112N, respectively.

[0013] In the following description, capital letter P is attached to the positive electrode side components, capital letter N is attached to the negative electrode side components, and for elements having the same or common structure, capital letters P and N are omitted and the same numerals are attached for description. For example, the positive electrode side electrode tab is denoted by reference numeral 112P, the negative electrode side electrode tab is denoted by reference numeral 112N, and when simply indicating the electrode tab, it is denoted by reference numeral 112 for description.

[0014] (Power generation element) Although not shown in the drawings, the power generation element includes a power generation body (not shown) in which a plurality of positive electrode sheets coated with a positive electrode active material and a plurality of negative electrode sheets coated with a negative electrode active material are laminated via a separator, and an electrolytic solution in which the power generation body is immersed within the exterior body 111. A positive electrode tab 112P is connected to the positive electrode sheet, and a negative electrode tab 112N is connected to the negative electrode sheet. The single cell 110 is, for example, a lithium ion secondary battery in which lithium ions move between the positive and negative electrode active materials to repeat discharging and charging. As an example, the positive electrode tab 112P is an aluminum-based metal, and the negative electrode tab 112N is a copper-based metal.

[0015] (Single cell unit) FIG. 4 is a perspective view of a single cell unit 115 composed of a single cell 110 and a pair of spacers 120P and 120N. As shown in FIGS. 1, 2, 9, etc., the spacer 120 is used for laminating a plurality of single cells 110. The positive electrode tab 112P and the negative electrode tab 112N of the single cell 110 are supported by the spacer 120. The positive electrode tab 112P protruding from one side 111a of a pair of short sides of the single cell 110 is electrically connected by laser welding at a joint 114 to a first bus bar 122P provided on the spacer 120P. The negative electrode tab 112N protruding from the other side 111b is electrically connected by laser welding at a joint 114 to a first bus bar 122N provided on the spacer 120N. Each joint 114 extends linearly along a direction parallel to the sides 111a and 111b, that is, along the width direction of the positive electrode tab 112P and the negative electrode tab 112N, with a predetermined welding width. That is, the single cell unit 115 is composed of a single cell 110 and a pair of spacers 120P and 120N.

[0016] (Spacer and first bus bar) FIG. 5 is a perspective view of a spacer 120 in which the first bus bars 122P and 122N are integrated, and FIG. 6 is an exploded perspective view of the spacer 120 and the first bus bar 122. FIG. 6(A) is a perspective view of the spacer 120 viewed obliquely from above, and FIG. 6(B) is a perspective view of the spacer 120 viewed obliquely from below. The positive electrode side spacer 120P has a spacer body 121 formed of an insulating material and a first bus bar 122P provided on the spacer body 121 and electrically connected to the positive electrode tab 112P. The negative electrode side spacer 120N has a spacer body 121 formed of an insulating material and a first bus bar 122N provided on the spacer body 121 and electrically connected to the negative electrode tab 112N. The first bus bar 122P on the positive electrode side is an aluminum-based metal, and the second bus bar 122N on the negative electrode side is a copper-based metal.

[0017] The spacer bodies 121P and 121N to which the first bus bars 122P and 122N are fixed have the same shape and are described by the same reference numeral 121. Also, the first bus bars 122P and 122N may have the same shape and be described by the same reference numeral 122. The spacer body 121 has a bus bar mounting portion 121a extending in a direction along the X-axis to which the first bus bars 122P and 122N are attached, and laminated portions 121b integrally provided at both ends of the bus bar mounting portion 121a. The laminated portion 121b is provided with a through hole 121e through which the through bolt 113a is inserted. A pair of bus bar engaging portions 121c are provided at a predetermined interval on the bus bar mounting portion 121a. The engaging plates 122b of the first bus bars 122P and 122N are engaged with the bus bar engaging portions 121c, and the first bus bars 122P and 122N are integrated and fixed to the spacer body 121a. The pair of bus bar engaging portions 121c of the spacer body 121 are provided outside a pair of position regulating protrusions 122d of the first bus bar 122 along the longitudinal direction of the spacer 120.

[0018] (First bus bar) As shown in FIG. 6, the first bus bar 122 includes an elongated strip-shaped side plate 122a disposed along the side surface of the bus bar mounting portion 121a of the spacer body 121, a pair of rectangular engaging plates 122b provided facing both ends of the side plate 122a, a top plate 122c connecting the side plate 122a and the engaging plates 122b, and a pair of position regulating protrusions 122d protruding from the top plate 122c in a direction along the Y axis. The position regulating protrusions 122d are inserted into the position regulating holes 113 provided in the electrode tabs 112P and 112N and engage with the electrode tabs 112, constituting a position regulating structure of the single battery 110 with respect to the spacer 120. The pair of engaging plates 122b are provided outside the pair of position regulating protrusions 122d along the longitudinal direction of the spacer 120.

[0019] (Second bus bar) The second bus bar 130 will be described with reference to FIG. 7. In the first embodiment, a plurality of single batteries 110 are electrically connected in two parallel series by connecting the second bus bar 130 to the first bus bar 122. That is, a pair of single batteries 110 are connected in parallel at one of the terminal portions 130P or 130N of the second bus bar 130 with one polarity to form a single battery pair 110C (see FIGS. 8 and 9). A plurality of these single battery pairs 110C are connected in series by a plurality of second bus bars 130. The second bus bar 130 is formed of a clad material in which a positive electrode terminal portion 130P made of an aluminum-based metal and a negative electrode terminal portion 130N made of a copper-based metal are integrated. As shown in FIGS. 2 and 8, the external positive electrode terminal 131P connected to the positive electrode terminal of the inverter by a high-voltage cable or the like and the external negative electrode terminal 131N connected to the negative electrode terminal of the inverter by a high-voltage cable or the like are not made of a clad material, but are made of an aluminum-based metal and a copper-based metal.

[0020] (Two parallel series connection type power source) The assembled battery 100 of the first embodiment is a two parallel series connection type power source in which a plurality of sets of single battery pairs 110C, each formed by connecting two single batteries 110 in parallel, are connected in series. FIG. 8 is a conceptual diagram of a two-parallel series-connected power supply. N single cell pairs, i.e., the single cell pair 110C-1 at the uppermost part of FIG. 8, the single cell pair 110C-2 connected below it, …, and the single cell pair 110C-N at the lowermost part, are serially connected by the second bus bar 130. The two-parallel series-connected power supply has an external positive terminal 131P and an external negative terminal 131N, and the charging current and the discharging current between the external load and the power supply are input and output via those external positive and negative terminals 131P and 131N. The external positive terminal 131P, the plurality of second bus bars 130, and the external negative terminal 131N are laser welded to the first bus bars 122P and 122N. In other words, the assembled battery 100 of the embodiment is a power supply configured as follows. The pair of positive electrode side electrode tabs 112P of the pair of single cells 110 are connected in parallel at the positive electrode terminal portion 130P, and the pair of negative electrode side electrode tabs 112N are connected in parallel at the negative electrode terminal portion 130N to form a single cell pair 110C. A plurality of sets 110C-1, 110C-2, …, 110C-N of the single cell pairs 110C connected in parallel are serially connected by the second bus bar 130. With such a connection form, the assembled battery 110 of the first embodiment is used as a power supply in which a plurality of single cells 110 are two-parallel series-connected.

[0021] (Position restricting structure) FIG. 9(A) is a cross-sectional view showing a position restricting structure in which the position restricting protrusion 122d of the first bus bar 122 is engaged with the position restricting hole 113 of the electrode tab 112, and (B) is a partially enlarged view thereof. As described with reference to FIG. 5, the first bus bar 122 is snap-fitted to the spacer body 121 and integrated. The electrode tab 111 having the position restricting hole 113 is placed on the first bus bar 122 of the spacer 120 such that the pair of position restricting protrusions 122d of the first bus bar 122 are engaged with the pair of position restricting holes 113. The electrode tab 112 is laser welded to the first bus bar 122 at the two joint portions 114 shown in FIG. 3. In the first embodiment, the joint portions 114 are provided between those position restricting holes 113.

[0022] The assembled battery 100 described above is manufactured as follows. This will be described with reference to FIG. 2. (1) Prepare the single cell 110 (FIG. 3). (2) Prepare spacers 120P and 120N (Fig. 5) in which the first bus bars 122P and 122N are integrated respectively. (3) Insert the position regulating projection 122d of the positive electrode side first bus bar 122P into the position regulating hole 113 of the positive electrode tab 112P, and insert the position regulating projection 122d of the negative electrode side first bus bar 122N into the position regulating hole 113 of the negative electrode tab 112N. Then, laser weld the electrode tabs 112P and 112N to the first bus bars 122P and 122N to fabricate a single cell unit 115 (Fig. 4). (4) Refer to Fig. 2. Stack a plurality of single cell units 115 at their spacer stacking portions 121b. Insert a through bolt 103a through the bolt through hole 121e of the spacer stacking portion 121b and fasten it with a nut 103b to fabricate a single cell group 150 including a plurality of single cell units 115.

[0023] (5) Refer to Fig. 2. Prepare second bus bar units 130A and 130B. The holder 130a holds the second bus bars 130, 131P, and 131N, and the holder 130b holds the second bus bar 130. In this way, the second bus bar units 130A and 130B are fabricated. The second bus bar units 130A and 130B are attached to both side portions of the single cell group 150. (6) Laser weld the second bus bars 130, 131P, and 131N to the corresponding first bus bars 122 respectively. (7) The assembled battery 100 assembled through the steps (1) to (6) above is a power source of a two - parallel - and - series connection type, and this power source is fixedly installed in a battery housing portion of a vehicle (not shown) with fixing bolts.

[0024] (Effect of the position regulating structure) When the vehicle collides with an object, an impact force is input to the battery pack 100. At this time, an impact force also acts on the components of the battery pack 100. However, the single battery 110 and the spacer 120 are mechanically coupled by a positioning structure including a positioning hole 113 and a positioning protrusion 122d. The single battery 110 does not undergo relative displacement with respect to the spacer 120, and damage to the single battery 110 due to the collision is prevented. Further, although the electrode tab 112 is joined to the first bus bar 122 by laser welding, the mechanical coupling force by the positioning structure is more effective against impact input than the welding joint force between the electrode tab 112 and the first bus bar 122. In the first embodiment, the impact input can be received by both welding joint and mechanical coupling. For example, relative displacement between the single battery 110 and the spacer 120 due to a vehicle collision is prevented. Thereby, damage to the single battery 110 can be prevented. Further, in the battery pack 100 of the first embodiment, since a positioning hole is not provided in the heat-sealed side as in the conventional example, there is no fear that the sealing in the heat-sealed side becomes insufficient.

[0025] (Advantages over the prior art) The conventional structure is a positioning structure in which a positioning hole provided in the heat-sealed side where the electrode tab 112 protrudes among the heat-sealed sides of the exterior body 111 of the single battery 110 engages with a positioning protrusion provided in the spacer body 121. Therefore, there is a fear that the bonding area of the heat-sealed side becomes small only in the region where the positioning hole is provided, and the heat sealing becomes insufficient. The exterior body 111 folds a resin laminate material and houses a power generation element inside. Then, the heat-sealed sides are heat-welded with two overlapping laminates to seal the inside of the laminate material. In the first embodiment, a positioning hole 113 is provided in the electrode tab 112, a positioning protrusion 122d is provided in the first bus bar 122 integrated with the spacer body 121, and a positioning structure in which the positioning protrusion 122d engages with the positioning hole 113 is adopted. Therefore, the heat-sealing region does not become narrow, and the heat-sealing associated with the positioning structure does not become insufficient.

[0026] The structure of each part of the single battery unit 115 will be described with reference to FIG. 4. (1) Unit structure of single battery and spacer Refer to FIG. 4. The spacer 120 has an elongated shape. The single battery 110 is assembled to the spacer 120 such that the longitudinal direction of the spacer 120 coincides with the width direction (X direction) of the electrode tab 112 protruding from the laminate exterior material 111, and a single battery unit 115 is configured. (2) Integrated structure of spacer and first bus bar Refer to FIG. 6. The positive electrode side spacer 120P and the first bus bar 122P, and the negative electrode side spacer 120N and the first bus bar 122N are snap - fit coupled outside a pair of position - regulating structures. That is, the engaging plate 122b provided outside the position - regulating projection 122d engages with the bus bar engaging portion 121c of the spacer 120, and the first bus bars 122P and 122N are integrated with the spacer 120. (3) Position - regulating structure between electrode tab and first bus bar Refer to FIGS. 4 and 9. The positive electrode side electrode tab 112P and the first bus bar 122P, and the negative electrode side electrode tab 112N and the first bus bar 122N are engaged and integrated as follows. That is, the position - regulating projection 122d of the first bus bar 122P is inserted into the position - regulating hole 113 of the electrode tab 112P, and the position - regulating projection 122d of the first bus bar 122N is inserted into the position - regulating hole 113 of the electrode tab 112N, forming a pair of position - regulating structures. (4) Joining structure between electrode tab and first bus bar The positive electrode side electrode tab 112P and the first bus bar 122P, and the negative electrode side electrode tab 112N and the first bus bar 122N are respectively laser - welded at a pair of joining portions 114 set at positions between a pair of position - regulating structures. The joining portions 114 extend in the longitudinal direction of the electrode tabs 112P and 112N, that is, in the longitudinal direction of the laminate sealing sides 111a and 111b where the electrode tabs 112P and 112N protrude.

[0027] By adopting the structures of (1) to (4) above, along the longitudinal direction of the spacer 120, a pair of joining portions 114, a pair of position - regulating structures, and a pair of snap - fit structures are arranged in a row (aligned), so that in the protruding direction of the electrode tab 112, the joining structure, position - regulating structure, and integrated structure of the electrode tab 112, the bus bar 122, and the spacer body 121 can be suppressed to be as small as possible.

[0028] The effects of the assembled battery 100 of the first embodiment are as follows. (1) The assembled battery 100 of the first embodiment includes a power generation element covered with a film-like exterior body 111, and a plurality of single cells 110 having a positive electrode tab 112P and a negative electrode tab 112N that are connected to the power generation element and protrude to the outside from sides 112P and 112N where the film of the exterior body 111 is heat-sealed, a plurality of spacers 120P and 120N that hold the plurality of single cells 110, a first bus bar 122P on the positive electrode side and a first bus bar 122N on the negative electrode side that are provided on the spacers 120P and 120N and are electrically connected to the positive electrode tab 112P and the negative electrode tab 112N, respectively, a positive electrode side engagement structure (position regulating hole 113 and position regulating projection 122d) that mechanically engages the first bus bar 122P on the positive electrode side and the positive electrode tab 112P, and a negative electrode side engagement structure (position regulating hole 113 and position regulating projection 122d) that mechanically engages the first bus bar 122N on the negative electrode side and the negative electrode tab 112N. The plurality of single cells 110 and the spacers 120 are laminated. In the assembled battery 100 of the first embodiment, the electrode tab 112P on the positive electrode side and the first bus bar 120P, and the electrode tab 112N on the negative electrode side and the first bus bar 120N are mechanically engaged to prevent relative displacement between the two due to a collision input. Therefore, deterioration of the heat-sealing performance of the exterior body 111 can be prevented compared to the conventional structure.

[0029] (2) In the assembled battery 100 of the first embodiment, the positive electrode tab 112P and the negative electrode tab 112N protrude to the outside from the opposing heat-sealing sides 111a and 111b of the single cell 110 and have both a positive electrode side engagement structure and a negative electrode side engagement structure. Therefore, relative displacement between the single cell 110 and the spacer 120 due to a collision input can be prevented more effectively.

[0030] (3) In the assembled battery 100 of the first embodiment, a pair of positive electrode side engaging structures each composed of a position regulating hole 113 and a position regulating projection 122d and a pair of negative electrode side engaging structures each composed of a position regulating hole 113 and a position regulating projection 122d are provided separately at intervals in the width direction of the electrode tab 112. The positive electrode tab 112P and the first bus bar 122P on the positive electrode side and the negative electrode tab 112N and the first bus bar 122N on the negative electrode side are electrically connected by laser welding at two locations between the pair of engaging structures. By performing laser welding in a wide region avoiding the projection 122d, the electrical joining between the electrode tab 112 and the first bus bar 122 is also good. (4) In the assembled battery 100 of the first embodiment, the integrated structure of the positive electrode side spacer 120P and the first bus bar 122P is provided outside the positive electrode side engaging structure in the longitudinal direction of the spacer 120P, and the integrated structure of the negative electrode side spacer 120N and the first bus bar 120N is provided outside the negative electrode side engaging structure in the longitudinal direction of the spacer 120N. Also, the positive electrode side electrode tab 112P and the first bus bar 122P are laser welded between the pair of positive electrode side engaging structures, and the negative electrode side electrode tab 112N and the first bus bar 122N are laser welded between the pair of negative electrode side engaging structures. In this way, a pair of snap-fit structures that integrate the spacer 120 and the first bus bar 122, a joining structure that laser welds the electrode tab 112 and the first bus bar 122 at a pair of joining portions 114, and a pair of position regulating structures that regulate the positions of the electrode tab 112 and the first bus bar 122 are arranged in a row (aligned) along the longitudinal direction of the spacer 120. Thereby, in a narrow region in the protruding direction of the electrode tab 112, the joining structure, the position regulating structure, and the integrated structure of the electrode tab 112, the bus bar 122, and the spacer body 121 can be arranged.

[0031] (5) In the assembled battery 100 of the first embodiment, the single cells 110 are held and stacked by a pair of spacers 120 provided on a pair of opposing sides 111a and 111b of the single cell 110, and second busbar units 130A and 130B that hold a plurality of second busbars 130, 131P, and 131N are provided on each side of the pair of sides 111a and 111b. The second busbars 130, 131P, and 131N are laser welded to the first busbars 122P and 122N, thereby constituting a power source in which a plurality of single cells 110 are connected in two parallel and series. As shown well in FIG. 8, single cell pairs 110C-1, 110C-2,..., 110C-N are stacked such that the positive electrode tabs 112P and the negative electrode tabs 112N are arranged alternately. In the first embodiment, a configuration is adopted in which a power source is connected in two parallel and series. However, by changing the shape, size, etc. of the second busbar 130, etc., a power source connected in three parallel and series can be obtained, or a power source in which all the single cells 110 are directly connected can be obtained. The degree of freedom in the design of the power source configuration increases, and one common single cell can be used in many vehicle models, contributing to cost reduction.

[0032] - Second Embodiment - In the second embodiment, after passing the position regulating projection 122d of the first busbar 122 through the position regulating hole 113 of the electrode tab 112, caulking is performed, and then the electrode tab 112 and the first busbar 122 are electrically joined by laser welding to produce the single cell unit 115. As a procedure, it has a step of inserting and passing the tip of the position regulating projection 122d through the position regulating hole 113 of the electrode tab 112, a caulking step of bending the tip of the position regulating projection 12d, and a step of electrically joining the electrode tab 112 and the first busbar 122 by laser welding. By caulking the position regulating projection 122d to the electrode tab 112, the mechanical bondability between the electrode tab 112 and the first busbar 122 is improved.

[0033] (Modification 1) In the assembled battery of the embodiment, a positive electrode side engaging structure for mechanically engaging the first bus bar 122P on the positive electrode side and the positive electrode tab 112P, and a negative electrode side engaging structure for mechanically engaging the first bus bar 122N on the negative electrode side and the negative electrode tab 112N are provided. However, the engaging structure may be provided only for the positive electrode tab 112P and the first bus bar 122P on the positive electrode side, or only for the negative electrode tab 112N and the first bus bar 12N on the negative electrode side. (Modification 2) In the assembled battery 100 of the embodiment, a pair of position regulating holes 113 are provided in the electrode tab 112, and a pair of position regulating protrusions 122d are provided in the first bus bar 122, and position regulation is performed at two locations of the electrode tab 112. However, the position regulation may be performed at one location or at three or more locations.

[0034] (Modification 3) In the assembled battery 100 of the embodiment, the positive electrode tab 112P and the negative electrode tab 112N protrude from a pair of sides 111a and 111b in the longitudinal direction of the single battery 110. However, the present invention can also be applied to a single battery in which the positive electrode tab 112P and the negative electrode tab 112N protrude separately from one side in the longitudinal direction, for example, side 111a. In this case, in the spacer, the first bus bar 122P on the positive electrode side and the first bus bar 122N on the negative electrode side are integrated with the spacer body, the positive electrode tab 112P is welded to the first bus bar 122P on the positive electrode side, and the negative electrode tab 112N is welded to the first bus bar 122N on the negative electrode side. In Modification 3, position regulating holes 113 are provided in each of the positive and negative electrode tabs 112P and 112N provided on the same side of the assembled battery, and position regulating protrusions 122d are provided in the first bus bars 122P and 122N, respectively. The position regulating structure may be provided only on one of the polarity sides.

[0035] (Modification 4) In the assembled battery 100 of the embodiment, the first bus bar 122 is attached to the spacer body 121 as a snap fit structure, but the first bus bar 122 may be integrated with the spacer body 121 by other attachment structures. For example, it may be a spacer 120 in which the first bus bar 122 is resin molded.

[0036] (Modification 5) In the assembled battery 100 of the embodiment, the electrode tabs 112P and 112N are joined to the first bus bars 122P and 122N, and the second bus bar 130 is joined to the first bus bars 122P and 122N to form a single battery group. However, the assembled battery may be configured with one type of bus bar joined to the electrode tabs 112P and 112N respectively. (Modification Example 6) In the assembled battery 100 of the embodiment, two single cells 110 in which the positive electrode tab 112P and the negative electrode tab 112N protrude from a pair of sides 111a and 111b in the longitudinal direction are connected in parallel to form a single cell pair 110C, and a plurality of these single cell pairs 110C are connected in series to form a two-parallel direct connection power source. Such a two-parallel series connection power source is an example, and for example, all of the plurality of single cells 110 may be connected in series as a power source.

[0037] (Modification Example 7) In the assembled battery 100 of the embodiment, a positive electrode side engagement structure that mechanically engages the first bus bar 122P on the positive electrode side and the positive electrode tab 112P, and a negative electrode side engagement structure that mechanically engages the first bus bar 122N on the negative electrode side and the negative electrode tab 112N are provided. That is, it is a structure in which each single cell is held by a spacer. However, a plurality of single cells 110 can also be held by one spacer 120. For example, a configuration in which a single cell pair 110C is held by one spacer 120 may be used.

[0038] (Modification Example 8) In the assembled battery 100 of the embodiment, a position regulating structure is formed by the protrusions 122d of the first bus bars 122P and 122N on the positive and negative electrode sides and the position regulating holes 113 of the positive and negative electrode tabs 112P and 112N. However, instead of the protrusions 122d of the first bus bar 122, a resin protrusion may be provided protruding from the upper surface (electrode tab mounting surface) of the spacer body 121, and a position regulating structure in which this protrusion is inserted into the engagement hole 113 of the electrode tab may be used. In this case, it is preferable to provide a protrusion from the spacer body 121 in the region where the electrode tab 112 and the first bus bar 122 overlap, that is, in the region to be laser welded. As an example of a specific configuration, a hole through which the resin protrusion passes is provided in the first bus bar 122, and the resin protrusion passes through the first bus bar 122 and is inserted into the position regulating hole 113 of the electrode tab 112.

[0039] (Modification Example 9) In the assembled battery 100 of the embodiment, the position restricting hole 113 is provided in the electrode tab 112, and the position restricting projection 122d is provided in the first bus bar 122. However, a position restricting projection may be provided in the electrode tab 112, and a position restricting hole may be provided in the first bus bar 122. (Modification Example 10) In the assembled battery 100 of the embodiment, the position restricting structure is constituted by the position restricting hole 113 and the position restricting projection 122d. However, as long as the position restricting structure has a function of suppressing the fluctuation of the relative position between the single battery 110 and the spacer 120, the position restricting structure may adopt a position restricting structure that does not depend on the position restricting hole 113 and the position restricting projection 122d.

[0040] In the above, various embodiments and modification examples have been described, but the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

Explanation of Reference Numerals

[0041] 100: Assembled battery 110: Single battery 110C: Pair of single batteries 111: Exterior body 111a to 111d: Heat-sealed sides 112, 112P, 112N: Electrode tabs 113: Position restricting holes 114: Joint portion 115: Single battery unit 120, 120P, 120N: Spacers 121: Spacer body 122, 122P, 122N: First bus bars 122d: Position restricting projections 130, 131P, 131N: Second bus bars 132a, 132b: Second bus bar holders 150: Group of single batteries

Claims

1. a power generating element covered with a film-like exterior body, and a plurality of unit cells each having a positive electrode tab and a negative electrode tab connected to the power generating element and protruding outward from an edge where the film of the exterior body is heat sealed; a first bus bar on a positive electrode side electrically connected to at least one of the positive electrode tabs; a first bus bar on a negative electrode side electrically connected to at least one of the negative electrode tabs; a support member that supports the positive electrode side first bus bar and the negative electrode side first bus bar; Equipped with a positive electrode side engagement structure that engages the positive electrode side first bus bar with the positive electrode tab, and a negative electrode side engagement structure that engages the negative electrode side first bus bar with the negative electrode tab.

2. 2. The battery pack according to claim 1, The positive electrode side engagement structure and the negative electrode side engagement structure are provided in pairs, The positive electrode tab and the positive side first bus bar, and the negative electrode tab and the negative side first bus bar are electrically connected between the pair of positive electrode side engagement structures and between the pair of negative electrode side engagement structures.

3. The battery pack according to claim 1 or 2, a battery pack, wherein an integrated structure between the positive electrode side support member and the first bus bar is provided outside the positive electrode side engagement structure in the longitudinal direction of the support member, and an integrated structure between the negative electrode side support member and the first bus bar is provided outside the negative electrode side engagement structure in the longitudinal direction of the support member.

4. The battery pack according to any one of claims 1 to 3, The plurality of unit cells are stacked, Each of the positive electrode side engagement structure and the negative electrode side engagement structure is a protrusion provided on each of the first bus bars on the positive electrode side and the negative electrode side and extending in a direction in which the unit cells are stacked; a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab being provided with a hole through which the protrusion passes.

5. The battery pack according to claim 4, The tip of the protrusion passing through the hole provided in each of the positive electrode tab and the negative electrode tab is bent.

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