JP7016797B2 - Battery pack and battery pack manufacturing method - Google Patents

Description

The present invention relates to a battery pack containing a battery connection structure in which battery cells such as a lithium ion secondary battery are connected, and a method for manufacturing the same.

Battery packs equipped with primary and secondary batteries are medium-sized power supplies for portable devices such as mobile phones, digital cameras, and laptop computers, as well as simple backup power supplies for electric carts and small equipment. It is also widely used as a power source and a large power source for vehicles and households.

The battery pack contains a battery such as a primary battery or a secondary battery and a circuit board including a protection circuit or the like in a container. Lithium-ion batteries with high energy density and light weight are often used as batteries to be mounted inside the container. Among them, a laminated battery using a laminated film made of a flexible aluminum sheet with a thickness of several tens to several hundreds of microns and a resin as an exterior material is particularly lightweight and is expected to be used for various purposes. Has been done.

Here, a battery cell using a flexible laminated film as an exterior material is excellent in weight reduction, but has lower strength than a square battery or a cylindrical battery using a thick metal plate as an exterior material. It has the problem of being vulnerable to external impact.

Further, when the battery capacity required by the device to which the battery pack is connected becomes large, it is inevitably necessary to connect and use a plurality of battery cells. When a plurality of laminated battery cells are housed in a battery pack, they are stacked in the stacking direction or arranged side by side in parallel with the inner surface of the outer case.

For example, Patent Document 1 (International Publication No. 2012/131802) discloses a battery pack containing a battery connection structure in which stacked battery cells are connected by a substrate.
International Publication 2012/131802

In the technique described in Patent Document 1, when a plurality of battery cells are connected to form a battery-connected structure, it is necessary to use a substrate, and a volume integral such as a substrate, a battery-connected structure, and thus a battery-connected structure are used. There was a problem that the battery pack became large. Further, the technique described in Patent Document 1 has a problem that the number of parts such as a substrate increases and the cost increases.

Based on the idea of reducing the size of the battery cell itself in order to avoid increasing the size of the battery pack, it is conceivable to prepare a battery cell having a structure in which the circumference of the laminated exterior material is folded back. However, when the periphery of the laminated exterior material is folded back, a new problem arises that the heat-welded portion may be cracked due to the folding back and the sealing performance may be impaired.

Further, in the technique described in Patent Document 1, when a plurality of battery cells are connected to form a battery connection structure, it is necessary to use a substrate, which increases the number of parts such as a substrate. Therefore, a battery is used. There was a problem that extra labor and cost were required when manufacturing the pack.

On the other hand, if it is attempted to connect a plurality of battery cells without using a substrate as described in Patent Document 1, the handling of the drawer tabs drawn out from the plurality of battery cells becomes complicated, so that the tabs are poorly connected to each other. There was also a problem that the possibility of occurrence of the above was increased and the yield was reduced.

The present invention solves the above-mentioned problems, and in the battery pack according to the present invention, three or more battery cells having a positive electrode drawer tab and a negative electrode drawer tab drawn from a laminate film exterior material are laminated. A battery pack including a battery connection structure in which the adjacent battery cells are electrically connected, wherein each tab of the adjacent battery cells is connected to a potential detection tab member and the potential detection tab member. The potential detection tab member has a lead wire connected to the base and an insulating member that insulates an electrical connection portion between adjacent battery cells, and the potential detection tab member is perpendicular to the base and the longitudinal direction of the base. The lead wire is connected to the protruding portion, and the positive lead-out tab of one battery cell and the negative-negative lead-out tab of another battery cell adjacent to one battery cell are formed. The tip portion of the potential detection tab member connected via the potential detection tab member, the tip portion of the base portion of the potential detection tab member is folded back together with the positive electrode drawer tab and the negative electrode drawer tab, and the tip portion of the potential detection tab member is folded back. However, it overlaps with the insulating member when viewed from the stacking direction of the battery cells.

Further, in the battery pack according to the present invention, a lead wire is connected to the potential detection tab member by soldering.

Further, in the battery pack according to the present invention, a spacer member is arranged between the tip of one battery cell and the tip of another battery cell adjacent to one battery cell.

Further, in the method for manufacturing a battery pack according to the present invention, three or more battery cells having a positive electrode drawer tab and a negative voltage drawer tab drawn from a laminated film exterior material are laminated, and the adjacent battery cells are electrically connected. It is a method of manufacturing a battery pack that manufactures a battery pack including the battery connection structure, wherein the drawer tabs of different poles overlap each other when viewed from the stacking direction of the battery cells, so that the first battery cell and the first battery cell are manufactured. The first laminating step of laminating the two battery cells, the first connecting step of connecting one of the overlapping drawer tabs of different poles to each other, and the direction in which the drawer tab is pulled out from the laminated film exterior material. In the opposite direction, the first folding step of folding back the drawer tabs of different poles connected in the first connection step and the pull-out tabs of different poles so as to overlap each other when viewed from the stacking direction of the battery cells are first. A part of the device for carrying out the connection step enters the space created by the second stacking step of laminating the battery cell of 3 and the second battery cell and the first folding step. It has a second connection step of connecting the tabs which are not connected in the first connection step among the drawer tabs of different poles overlapped in the two stacking steps .

Further, in the method for manufacturing a battery pack according to the present invention, the third battery cell and the second battery cell are laminated so that the drawer tabs of different poles overlap each other when viewed from the stacking direction of the battery cells. Of the drawer tabs of different poles overlapped in the second laminating step and the second laminating step, the second connecting step of connecting the tabs not connected in the first connecting step and the drawer tab are the laminate film exterior. It has a second folding step of folding back the drawing tabs of different poles connected in the second connecting step in a direction opposite to the direction of drawing from the material.

Further, in the method for manufacturing a battery pack according to the present invention, a positive electrode addition tab member is added to the positive electrode drawer tab drawn from the laminated film exterior material.

Further, in the method for manufacturing a battery pack according to the present invention, in the first connection step and the second connection step, the potential detection tab member is connected together with the drawer tabs of different poles.

Further, in the method for manufacturing a battery pack according to the present invention, a lead wire is connected to the potential detection tab member by soldering.

Further, in the method for manufacturing a battery pack according to the present invention, the potential detection tab member has a base portion and a protruding portion protruding perpendicular to the longitudinal direction of the base portion, and the lead wire is provided on the protruding portion. Is connected.

Further, in the method for manufacturing a battery pack according to the present invention, the position of the protruding portion of the potential detection tab member is not changed when the drawer tabs of different poles are folded back in the first folding step and the second folding step. Only the base is folded back.

According to the battery pack according to the present invention, since the number of parts such as a substrate does not increase, the battery pack can be provided at low cost.

Further, according to the battery pack according to the present invention, it is possible to provide a battery pack in which the size of the laminated exterior material is suppressed from being increased in size without causing deterioration of the sealing property due to folding back of the peripheral portion.

Further, according to the method for manufacturing a battery pack according to the present invention, the number of parts such as a substrate does not increase, so that extra labor and cost are not required at the time of manufacturing the battery pack.

Further, according to the method for manufacturing a battery pack according to the present invention, the yield is not reduced.

It is a figure which shows the battery cell 100 used in the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the state of joining the positive electrode addition tab member 125 to the positive electrode pull-out tab 120 of a battery cell 100. It is a figure which shows the battery cell 100 to which the positive electrode addition tab member 125 is joined. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure explaining the potential detection tab member 200 used in manufacturing a battery connection structure 500. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the resistance welding process of three tab members, and the folding process. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows typically the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows typically the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows typically the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows typically the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows typically the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows typically the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows typically the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the battery pack 700 which concerns on embodiment of this invention. It is a figure which shows the battery pack 700 which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a battery cell 100 used in the battery pack 700 according to the embodiment of the present invention. As such a battery cell 100, a lithium ion secondary unit battery in which charging and discharging are performed by moving lithium ions between a negative electrode and a positive electrode is used.

In the battery body 110 of the battery cell 100, an electrode laminate in which a plurality of sheet-shaped positive electrodes and a plurality of sheet-shaped negative electrodes are laminated via a separator, and an electrolytic solution (none of which is shown) are rectangular in a plan view. It has a structure housed in the laminated film exterior material 103. The positive electrode drawing tab 120 and the negative electrode drawing tab 130 are pulled out from the first end portion 111 of the battery main body 110.

Both the positive electrode drawer tab 120 and the negative electrode drawer tab 130 have a flat plate shape, and are connected to the sheet-shaped positive electrode and the sheet-shaped negative electrode directly or via a lead body in the laminated film exterior material 103, respectively. The laminating film exterior material 103 is made of a metal laminating film having a heat-sealed resin layer on the inner surface of the battery. More specifically, for example, two metal laminating films are laminated to form a laminating film exterior material 103, and an electrode laminate having a sheet-shaped positive electrode, a sheet-shaped negative electrode, and a separator and an electrolytic solution are housed therein. The outer periphery (first end portion 111, second end portion 112, two side end portions 113) of the laminating film exterior material is heat-sealed to seal the inside thereof.

Here, the metal piece drawn from the battery body 110 made of the laminated film exterior material 103 such as the positive electrode drawer tab 120 and the negative electrode drawer tab 130 is referred to as a “drawer tab”, and the separator is inside the laminated film exterior material 103. Sheet-shaped positive electrodes and sheet-shaped negative electrodes that are laminated via an electrolytic solution or the like are referred to as "electrodes".

In addition to the electrode laminate in which a plurality of sheet-shaped positive electrodes and a plurality of sheet-shaped negative electrodes are laminated via a separator as described above, a sheet-shaped positive electrode and a sheet-shaped negative electrode are laminated via a separator. It also includes those that form a laminated body by winding and compressing it.

In the battery cell 100 as described above, aluminum or an aluminum alloy is used as the material of the positive electrode extraction tab 120, nickel is used as the material of the negative electrode extraction tab 130, and nickel plating is applied to another metal (nickel plating). Materials such as nickel-plated copper), nickel and other metal clads (nickel clad materials such as nickel-copper clad) are commonly used. That is, the battery cell 100 has a positive electrode drawing tab 120 containing aluminum and a negative electrode drawing tab 130 containing nickel. In the present embodiment, an aluminum positive electrode drawer tab 120 and a nickel negative electrode drawer tab 130 are used.

In a configuration in which the positive electrode drawer tab 120 containing aluminum of the battery cell 100 and another conductive metal are directly connected, the conductivity may deteriorate after a predetermined period of time due to the problem of the potential difference between the metals. There is.

Therefore, in the present invention, the positive electrode extension tab member 125 containing nickel is joined to the positive electrode drawing tab 120 of the battery cell 100 by resistance welding or ultrasonic welding to solve the problem of conductivity deterioration due to the problem of potential difference. I try to do it.

The configuration for this will be described in more detail. As shown in FIG. 1, in constructing the battery connection structure 500, the aluminum positive electrode drawer tab 120 in the battery cell 100 has a length a from the first end 111, and is made of nickel (or a material containing nickel). The negative electrode drawer tab 130 of (manufactured by) has a length b (b> a) from the first end portion 111.

Next, for the aluminum positive electrode drawer tab 120 having a length a, the nickel positive electrode replenishment tab member 125 is resistance welded or ultrasonically welded so that the length from the first end 111 is b. It is joined and added by such means (see FIGS. 2 and 3).

Hereinafter, the entire drawer tab formed by joining the positive electrode replenishment tab member 125 may be referred to as a “positive electrode drawer tab”. As shown in FIG. 3, by adding the positive electrode addition tab member 125 to the positive electrode drawing tab 120, the length of the entire positive electrode drawing tab from the first end portion 111 becomes b.

In the battery pack 700 according to the present invention, the entire positive electrode extraction tab including the positive electrode extraction tab 120 and the positive electrode addition tab member 125 added to the positive electrode extraction tab 120 is in contact with the potential detection tab member 200. In this state, the battery connection structure 500 is configured. The potential detection tab member 200 is manufactured of nickel or a material containing nickel.

As described above, in the battery pack 700 according to the present invention, when a plurality of battery cells 100 are electrically connected in series, the members containing nickel (additional tab member 125, potential detection tab member 200) are brought into contact with each other. Since the drawer tabs are connected to each other, the electrical connection between adjacent unit batteries (battery cell 100) is made of the same kind of metal material, there is no problem of potential difference, and the electrical conductivity is increased over the years. Almost no deterioration occurs.

Next, a method of stacking a plurality of battery cells 100 configured as described above to form a battery connection structure 500 in which adjacent battery cells 100 are electrically connected and thereby manufacturing a battery pack 700 will be described.

Hereinafter, in the present embodiment, a case where seven battery cells 100 are stacked and connected in series to form a battery connection structure 500 will be described as an example, but the present invention is not limited to this case. In the present invention, the number of stacked battery cells 100 is arbitrary. Further, in the present invention, when the battery cells 100 are electrically connected to each other, it is possible to appropriately select whether the connection form is a series connection or a parallel connection.

FIG. 4 is a diagram showing a manufacturing process of the battery pack 700 according to the embodiment of the present invention. FIG. 4 shows a step of preparing the first battery cell 100 among the seven battery cells 100 to be stacked.

In the process of FIG. 4, the insulating member 310 for protecting the cell is arranged on the first end 111 side of the battery cell 100. As a result, the battery cell 100 is protected by the insulating member 310. As the insulating member 310, a tape having flame retardancy and electrical insulation can be used. As will be described later, the battery cell 100 undergoes a step of joining tabs to each other by resistance welding or the like. At this time, the insulating member 310 protects the battery cell 100 having the laminated film exterior material 103.

When the insulating member 310 is attached to the battery cell 100, the potential detection tab member 200 is then placed on the positive electrode pull-out tab 120 and the positive electrode addition tab member 125. In the process shown in FIG. 4, the potential detection tab member 200 in which the signal lead wire 230 and the power supply line 240 are solder-connected is used.

The positive electrode pull-out tab 120, the positive electrode addition tab member 125, and the potential detection tab member 200 shown in FIG. 4 serve as the positive electrode of the battery connection structure 500 itself in which seven battery cells 100 are connected in series. The power line 240 functions as a lead wire for the positive electrode of the battery connecting structure 500. On the other hand, the signal lead wire 230 is used to detect the potential of the battery cell 100.

Here, the potential detection tab member 200 will be described in more detail. FIG. 5 is a diagram illustrating a potential detection tab member 200 used when manufacturing the battery connection structure 500.

FIG. 5A is a diagram showing only the potential detection tab member 200 extracted, and FIG. 5B is a diagram showing the potential detection tab member 200 in which the signal lead wire 230 and the power supply line 240 are solder-connected. 5 (C) is a diagram showing a potential detection tab member 200 to which a signal lead wire 230 is solder-connected.

In the present invention, when assembling the battery connection structure 500, as the potential detection tab member 200, the signal lead wire 230 and the power supply line 240 are already solder-connected as shown in FIGS. 5 (B) and 5 (C). The one shown is used. This is because when the signal lead wire 230 and the power supply line 240 are solder-connected in the process after joining the potential detection tab member 200 to the drawer tab, the active material and the electrolytic solution (both not shown) in the battery cell 100 are adversely affected. This is because it causes.

Materials constituting the potential detection tab member 200 include nickel, a material obtained by plating other metals with nickel (nickel-plated material, for example, nickel-plated copper), and a clad of nickel and other metals (nickel clad material). For example, nickel-copper clad) is used.

The potential detection tab member 200 is a flat plate member, and has a base 210 that is supposed to be superimposed on the drawer tab in the assembly process of the battery connection structure 500, and a protrusion 220 that protrudes from the base 210. is doing.

When the potential detection tab member 200 is superimposed on the drawer tab, the direction parallel to the direction in which the drawer tab is pulled out from the laminated film exterior material 103 is defined as the longitudinal direction of the base 210. The protrusion 220 is adapted to project perpendicular to the longitudinal direction of the base 210. Further, the width length of the base 210 (the length in the direction perpendicular to the longitudinal direction) is the same as the width length of each drawer tab. Further, the length of the base portion 210 in the longitudinal direction is set so that when one end portion is overlapped with the end portion of the positive electrode addition tab member 125, the other end portion overlaps with the insulating member 310. .. The state in which the other end of the base 210 overlaps the insulating member 310 is shown in FIG.

The base 210 of the potential detection tab member 200 may be overlapped with the entire positive electrode tab composed of the positive electrode extraction tab 120 and the positive electrode addition tab member 125, may be overlapped with the negative electrode extraction tab 130, or may be overlapped with the entire positive electrode tab. It is overlapped with both of the negative electrode drawing tabs 130 and is electrically and physically bonded to them by resistance welding or the like.

On the other hand, the protruding portion 220 of the potential detection tab member 200 is used as a conductive connection portion with the signal lead wire 230 and the power supply line 240.

The end of the signal lead wire 230 that is not connected to the protrusion 220 of the potential detection tab member 200 is connected to a conductive portion (not shown) of the connector member 260.

Further, when the end portion of the power supply line 240 that is not connected to the protruding portion 220 of the potential detection tab member 200 is used as the power supply line for the positive electrode of the battery connecting structure 500, the power supply is supplied via the fuse portion 243. It is connected to the terminal 245.

Further, when the end of the power supply line 240 that is not connected to the protrusion 220 of the potential detection tab member 200 is used as the power supply line for the negative electrode of the battery connection structure 500, it is directly connected to the power supply terminal 245. To.

In the manufacturing process of the battery connection structure 500, the potential detection tab member 200 is folded back together with each of the joined drawer tabs. In FIGS. 5B and 5C, the line to be folded back in the assembly process is shown by a dotted line. The process of folding back the drawer tab and the potential detection tab member 200 will be described later.

If the potential detection tab member 200 as used in the present invention is omitted to manufacture the assembled battery, the lead is connected to the cell in advance, so that the lead is the container of the cell when stacking. Or may come into contact with other poles. In addition, in order to prevent this, it is necessary to stack the cells while collecting long leads, which reduces the productivity. In order to prevent such a situation, it is preferable to use the potential detection tab member 200.

In the subsequent step shown in FIG. 6, the positive electrode pull-out tab 120 and the potential detection tab member 200 placed on the positive electrode addition tab member 125 are in a state of being welded to the positive electrode addition tab member 125 by resistance welding. In this embodiment, resistance welding is used for joining the tabs, but other joining methods such as ultrasonic welding can also be used.

In the subsequent step shown in FIG. 7, the step of folding back the positive electrode drawer tab 120, the positive electrode addition tab member 125, and the potential detection tab member 200 in the direction opposite to the direction in which the positive electrode drawer tab 120 is pulled out from the laminated film exterior material 103. implement. In such a folding step, the length of the entire tab member of the positive electrode becomes c from the first end portion 111. The space corresponding to the folded portion bc is used when stacking the battery cells 100 in the subsequent steps.

When the positive electrode pull-out tab 120, the positive electrode addition tab member 125, and the potential detection tab member 200 are folded back in the folding step, each tip is placed on the insulating member 310. The dimensions of the tabs and insulating members 310 are specified. Such an insulating member 310 can protect the laminated film exterior material 103 of the battery cell 100 from drawer tabs, tab members, and the like.

Further, in the battery pack 700 according to the present invention, since the folding step as described above is applied to the drawer tab, the tab member, and the like, the volumetric efficiency of the battery pack 700 can be improved.

Further, according to the battery pack 700 according to the present invention, the space that can be provided by the folding process can improve the manufacturability and the yield.

Further, in the battery pack 700 according to the present invention, in the folding step as described above, folding is performed so that the position of the protruding portion 220 of the potential detection tab member 200 is not changed by folding. (See also the scheduled folding lines in FIGS. 5B and 5C.) As a result, there is no influence such as stress on the protrusion 220 due to the folding of the potential detection tab member 200, and therefore the protrusion 220 is not affected. There is no effect on the connected signal lead wire 230, power supply line 240, or the like.

In the subsequent step shown in FIG. 8, the spacer member 330 on the first end side, which functions as a cushion member, is placed on the positive electrode drawer tab 120, the positive electrode addition tab member 125, and the potential detection tab member 200 folded back in the previous step. It will be placed. The spacer member 330 between the cells on the first end side has electrical insulation and cushioning properties, and is preferably flame-retardant. Further, the spacer member 330 between the cells on the first end side is prevented from protruding into the space corresponding to the previous bc.

Next, the process of stacking the battery cells is shown in FIG. A prime symbol (') is attached to the stacked battery cells to distinguish them from the first battery cell.

In the steps shown in FIGS. 9 and 10, when the second battery cell 100'is laminated on the first battery cell 100, the main bodies of the laminated film exterior materials 103 are attached with two double-sided adhesive tapes 320. Use to fix.

Further, at this time, the negative electrode extraction tab 130'of the second battery cell 100'is placed on the positive electrode extraction tab 120 of the first battery cell 100, and the negative electrode extraction tab 130 of the first battery cell 100 is provided. The positive electrode pull-out tab 120'of the second battery cell 100'and the positive electrode addition tab member 125'are placed above the battery cell 100'.

Further, only the signal lead wire 230'is solder-bonded between the negative electrode extraction tab 130 of the first battery cell 100, the positive electrode extraction tab 120'of the second battery cell 100', and the positive electrode addition tab member 125'. The potential detection tab member 200'is arranged. That is, the three tab members are aligned when viewed from the vertical direction.

Here, the end portion of the positive electrode addition tab member 125', the end portion of the potential detection tab member 200', and the end portion of the negative electrode extraction tab 130 are substantially aligned when viewed from the vertical direction (that is, all the end portions). However, the length from the first end portion 111 is approximately b).

In the subsequent step shown in FIG. 11, three tab members (negative electrode pull-out tab 130, potential detection tab member 200', positive electrode addition tab member 125') aligned in the vertical direction are attached to the anvil portion of the resistance welding device 1000 from above and below. The sandwiching resistance welding is performed between the 1010 and the horn portion 1020.

FIG. 12 is a diagram showing a resistance welding process and a folding process of three tab members (negative electrode pull-out tab 130, potential detection tab member 200', positive electrode addition tab member 125'). FIG. 12 is a side view of the drawer tab drawn out from the laminated film exterior material of the battery cell and the potential detection tab member.

In FIG. 12A, the three tab members (negative electrode pull-out tab 130, potential detection tab member 200', positive electrode addition tab member 125') to be subjected to resistance welding, as shown in FIG. 11, are the anvil portion 1010. , The state set between the horn portion 1020 and the horn portion 1020 is shown.

FIG. 12B shows a state in which a welding operation is executed by the resistance welding device 1000 and three tab members (negative electrode pull-out tab 130, potential detection tab member 200', positive electrode addition tab member 125') are resistance welded. ing.

FIG. 12C is a diagram showing a state in which three resistance-welded tab members (negative electrode pull-out tab 130, potential detection tab member 200', positive electrode addition tab member 125') are taken out from the resistance welding device 1000. ..

FIG. 12D shows the three resistance-welded tab members (negative electrode drawer tab 130, potential detection tab member 200', positive electrode replenishment tab member 125') in the direction in which the drawer tab is pulled out from the laminated film exterior material. The process of folding back is shown in the opposite direction.

In such a folding process, the lengths of the three resistance-welded tab members (negative electrode pull-out tab 130, potential detection tab member 200', positive electrode addition tab member 125') are from the first end portion 111 to c. .. The space corresponding to the folded portion bc shown in the figure is the space corresponding to the anvil portion 1010 and the horn portion 1020 of the resistance welding apparatus 1000 when the battery cells 100 are laminated and the tab members are resistance welded to each other in the subsequent steps. It is used as a space for people to enter.

FIG. 13 shows a state in which three resistance-welded tab members (negative electrode pull-out tab 130, potential detection tab member 200', positive electrode addition tab member 125') are subjected to a folding process.

In the subsequent step shown in FIG. 14, a state in which the spacer member 330 ′ between the cells on the first end side is arranged and the third battery cell 100 ″ is laminated is shown. A double-sided adhesive tape 320'not shown is used for fixing the battery cell 100 ″.

Here, the outline of manufacturing the battery pack 700 according to the present invention will be briefly reviewed. 15 to 21 are views schematically showing a manufacturing process of the battery pack 700 according to the embodiment of the present invention.

In a series of figures, the battery cells 100 are given ordinal numbers such as "first" and "second" in the order of stacking. Further, the positive electrode pull-out tab 120 drawn out from the battery cell 100 and the positive electrode addition tab member 125 added to the positive electrode pull-out tab 120 are marked with a (+) symbol, and the negative electrode pull-out tab 130 drawn out from the battery cell 100 is marked with (-). I added a symbol. In the description of the manufacturing process using a schematic diagram, they are referred to as (+) tabs, (-) tabs, and the like.

The ordinal numbers such as "first" and "second" are also used for the laminating process of laminating the battery cells, the connecting process of connecting the tab members of the battery cells by resistance welding, and the folding process after the connecting process. Was attached. Further, since it is complicated, the potential detection tab member is not shown.

FIG. 15 shows a process of preparing a first battery cell. A potential detection tab member (not shown) is connected to the (+) tab of the first battery cell, and these are folded back.

FIG. 16 shows a step of laminating a second battery cell on a first battery cell (first laminating step), and further, a (−) tab of the first battery cell and a second battery cell. It shows how the step (first connection step) of connecting the (+) tab of (+) and the potential detection tab member (not shown) was carried out.

Subsequently, as shown in FIG. 17, a step of folding back the (-) tab of the first battery cell, the (+) tab of the second battery cell, and the potential detection tab member (not shown) (first folding step). ).

FIG. 18 shows a step of laminating a third battery cell on a second battery cell (second laminating step), and further, a (−) tab of the second battery cell and a third battery cell. It shows how the step (second connection step) of connecting the (+) tab of (+) and the potential detection tab member (not shown) was carried out.

Subsequently, as shown in FIG. 19, a step of folding back the (-) tab of the second battery cell, the (+) tab of the third battery cell, and the potential detection tab member (not shown) (second folding step). ).

FIG. 20 shows a step of stacking a fourth battery cell on a third battery cell (third stacking step), and further, a (−) tab of the third battery cell and a fourth battery cell. It shows how the step (third connection step) of connecting the (+) tab of (+) and the potential detection tab member (not shown) was carried out.

Here, the third connection step is actually carried out by using the resistance welding device 1000, but at this time, the space for the anvil portion 1010 and the horn portion 1020 of the resistance welding device 1000 is created by the first folding step. You can utilize the space.

In order to provide such a space, as shown in FIG. 21, the (-) tab of the third battery cell, the (+) tab of the fourth battery cell, and the potential detection tab member (not shown) are provided. The folding step (third folding step) is carried out.

In the battery pack manufacturing method as described above, as shown in the series of schematic diagrams above, by sequentially performing the folding steps, a space for connecting the battery cells can be secured, and the battery cells can be secured. It is possible to efficiently connect between them. As described above, the method for manufacturing a battery pack according to the present invention does not require extra parts such as a substrate for connecting battery cells, and also requires labor and cost in manufacturing due to the extra parts. Can be reduced.

By repeating the stacking step → connecting step → folding step as described above, in the present embodiment, the seventh battery cell 100 is laminated, and as shown in FIG. 22, a signal is placed on the negative electrode drawing tab 130. The potential detection tab member 200 in which the lead wire 230 and the power supply line 240 are solder-connected is placed.

In the subsequent step shown in FIG. 23, a connection step of connecting the negative electrode drawing tab 130 and the potential detection tab member 200 by resistance welding is carried out, and further, a folding step of folding them back is carried out, and a spacer member between cells on the first end side is carried out. The 330 is attached to complete the battery connection structure 500.

In the subsequent step shown in FIG. 24, the power supply terminal 245 of the positive electrode of the battery connection structure 500, the power supply terminal 245 of the negative electrode, and the connector member 260 are electrically connected to a control board (not shown). Further, a plurality of second end-side inter-cell spacer members 340, which are flame-retardant cushion members, are attached to the second end 112 side of the plurality of battery cells 100 constituting the battery connection structure 500.

In the battery pack 700 according to the present embodiment, as a cushion member between the battery cells 100 to be stacked, a plurality of spacer members 330 between the first end side cells are provided on the first end portion 111 side of the battery cell 100, and the battery cell is also provided. A plurality of spacer members 340 between the cells on the second end side are provided on the second end 112 side of the 100 so as to absorb the impact on the battery cell 100.

Not limited to this, the spacer member 330 between the cells on the first end side, the spacer member 340 between the cells on the second end side, and the two connecting members (distributed in the vicinity of the two side end portions 113 of the battery cell 100) are arranged. A frame-shaped structure (not shown) composed of a member) and a frame-shaped structure (not shown) may be used to absorb the impact on the battery cell 100.

Further, in the battery pack 700 according to the present embodiment, the first plate 410 is attached to the first battery cell 100 of the battery connecting structure 500 with a double-sided adhesive tape (not shown). Further, the second plate 420 is attached to the second end 112 side of the battery cell 100 with a double-sided adhesive tape (not shown). A synthetic resin material such as ABS resin, polyethylene terephthalate resin, or polycarbonate resin can be used for the first plate 410 and the second plate 420.

Further, a bottom spacer member 350, which is a flame-retardant cushion member, is attached to the first plate 410 by using double-sided adhesive tape 320.

The battery pack 700 according to the present invention is completed by storing the battery connecting structure 500 and the above accessories in a case. FIG. 25 is a diagram showing a battery pack 700 according to an embodiment of the present invention. The outline of the case is shown by the dotted line.

According to the method for manufacturing the battery pack 700 according to the present invention as described above, since the number of parts such as a substrate does not increase, no extra labor or cost is required at the time of manufacturing the battery pack 700.

Further, according to the method for manufacturing the battery pack 700 according to the present invention, the yield is not reduced.

Further, according to the battery pack 700 according to the present invention, since the number of parts such as a substrate does not increase, the battery pack 700 can be provided at low cost.

Further, according to the battery pack 700 according to the present invention, it is possible to provide the battery pack 700 that suppresses the increase in size without causing deterioration of the sealing property due to folding back of the peripheral portion of the laminated exterior material.

Industrial applicability

The present invention relates to a battery pack composed of a unit cell using a flexible laminated film as an exterior material, which is lightweight, highly safe, and has high energy density. When a substrate is used to connect a plurality of battery cells to form a battery-connected structure, there is a problem that the volume of the substrate and the like, the battery-connected structure, and eventually the battery pack become large. Further, there is a problem that the number of parts such as a substrate increases and the cost increases.

Therefore, in the battery pack according to the present invention, the potential detection tab member is composed of a base portion and a protruding portion that protrudes perpendicularly to the longitudinal direction of the base portion, and the lead wire is connected to the protruding portion. The potential detection tab member is folded back together with the connected tab, and the tip portion of the folded back potential detection tab member is placed on the insulating member. According to such a configuration, Since the number of parts such as boards does not increase, battery packs can be provided at low cost, and the industrial usability is very high.

100 ... Unit cell 103 ... Laminated film exterior material 105 ... Electrode laminated area 110 ... Battery body 111 ... First end 112 ... Second end 113 ... Side end Part 119 ... Chamfering part 120 ... Positive electrode pull-out tab 125 ... Positive electrode addition tab member 130 ... Negative electrode pull-out tab 200 ... Potential detection tab member 210 ... Base 220 ... Protruding part 230 ...・ ・ Signal lead wire 240 ・ ・ ・ Power supply line 243 ・ ・ ・ Fuse part 245 ・ ・ ・ Power supply terminal 260 ・ ・ ・ Connector member 310 ・ ・ ・ Insulation member (for cell protection)
320 ... Double-sided adhesive tape 330 ... Spacer member between cells on the first end side (cushion member)
340 ... Spacer member between cells on the second end side (cushion member)
350 ... Bottom spacer member (cushion member)
410 ... 1st plate 420 ... 2nd plate 500 ... Battery connection structure 700 ... Battery pack 1000 ... Resistance welding device 1010 ... Anvil part 1020 ... Horn part

Claims (4)

A battery pack including a battery connection structure in which three or more battery cells having a positive electrode drawer tab and a negative electrode drawer tab drawn from a laminated film exterior material are laminated and the adjacent battery cells are electrically connected.
Each tab of the adjacent battery cell is connected to the potential detection tab member,
The lead wire connected to the potential detection tab member and
It has an insulating member that insulates an electrical connection between adjacent battery cells.
The potential detection tab member includes a base portion and a protruding portion that protrudes perpendicularly to the longitudinal direction of the base portion, and the lead wire is connected to the protruding portion.
The positive electrode drawer tab of one battery cell and the negative electrode drawer tab of another battery cell adjacent to one battery cell are connected via the potential detection tab member.
The tip of the potential detection tab member at the base is folded back together with the positive electrode drawer tab and the negative electrode withdrawal tab, and the folded tip of the potential detection tab member is viewed from the stacking direction of the battery cell. A battery pack that overlaps with the insulating member. The battery pack according to claim 1, wherein a lead wire is connected to the potential detection tab member by soldering. The battery pack according to claim 1 or 2, wherein a spacer member is arranged between the tip of one battery cell and the tip of another battery cell adjacent to one battery cell. A battery for manufacturing a battery pack including a battery connection structure in which three or more battery cells having a positive electrode drawer tab and a negative electrode drawer tab drawn from a laminated film exterior material are laminated and the adjacent battery cells are electrically connected. It ’s a pack manufacturing method.
The first laminating step of laminating the first battery cell and the second battery cell so that the drawer tabs of different poles overlap each other when viewed from the stacking direction of the battery cells.
The first connection step of connecting one of the overlapping drawer tabs of different poles to each other, and
In the first folding step of folding back the drawer tabs of different poles connected in the first connecting step in the direction opposite to the direction in which the drawer tab is pulled out from the laminated film exterior material,
A second stacking step of stacking the third battery cell and the second battery cell so that the drawer tabs of different poles overlap each other when viewed from the stacking direction of the battery cells.
Of the drawer tabs of different poles overlapped in the second laminating step, the second connecting step of connecting the tabs not connected in the first connecting step and the second connecting step.
A second folding step of folding back the drawer tabs of different poles connected in the second connecting step in the direction opposite to the direction in which the drawer tab is pulled out from the laminated film exterior material.
A third laminating step of laminating the fourth battery cell and the third battery cell so that the drawer tabs of different poles overlap each other when viewed from the stacking direction of the battery cells.
By entering a part of the device for carrying out the connection step into the space created by the first folding step, among the drawing tabs of different poles overlapped in the third laminating step, in the second connecting step. A method of manufacturing a battery pack having a third connection step of connecting tabs that are not connected to each other.

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