JP2013161632A - Power storage device, insulation member for battery, and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery which can facilitate assembly of a case and an electrode body while ensuring insulation thereof, and to provide an insulation member for a battery, and a vehicle.SOLUTION: A case 3 of a secondary battery 2 is formed in rectangular prism, and a rectangular prism electrode body 5 corresponding to the shape of the case is housed in the case 3. The electrode body 5 has a one-way current collection structure where positive and negative collectors 21, 22 are disposed on an upper surface 23f. Five faces of the electrode body 5, i.e., a front face 23a, a back face 23b, a right side face 23c, a left side face 23d and a rear face 23e are wrapped entirely with an insulating film 28. An insulation tape 30 having an adhesive surface is stuck to both ends of the insulating film 28 so as to cover the collectors 21, 22 completely, thus affixing the insulating film 28 to the electrode body 5. A third film plane 28c and a fourth film plane 28d on the left and right of the insulating film 28 are pushed by the circumference of an aperture 4a and closed when the electrode body 5 is housed in the case 3.

Description

  The present invention relates to a chargeable / dischargeable power storage device, a battery insulating member, and a vehicle.

  As is well known, rechargeable secondary batteries can be used repeatedly, and are therefore widely used in various devices and apparatuses. In the field of vehicles, the use of fossil fuels (reduction of carbon dioxide emissions) is required, so vehicles that use this type of secondary battery as a motor power source, so-called hybrid vehicles and EV vehicles (Electric Vehicle vehicles) ) And so on. In such a secondary battery, charging and discharging with a large current and an increase in battery capacity are required. For example, lithium ion secondary batteries are mass-produced as products.

  As shown in FIG. 11, this type of secondary battery 81 is assembled by housing an electrode body 83 inside a box-shaped case 82. The electrode body 83 includes a large number of positive electrodes and negative electrodes, and separators (polyethylene film) layered between these electrodes. The case 82 is made of metal in terms of strength and the like. Therefore, in order to insulate the electrode body 83 from the case 82, a technique has been proposed in which an insulating member (insulating film 84) is provided between the case 82 and the electrode body 83 (see Patent Document 1, etc.).

JP-A-6-338304

  By the way, if there is a place where insulation is not provided in the case 82 and the electrode body 83, a space for securing insulation is required in the part, and there is a problem that a dead space occurs. Since the dead space becomes a useless space that does not function as an electrode, there is a concern that the energy density of the secondary battery 81 will be adversely affected, and that downsizing of the device may be hindered. Therefore, there has been a need to develop an insulating structure that reliably insulates the case 82 and the electrode body 83.

  Further, in the case of FIG. 11, since the electrode body is inserted from the opening on the upper surface of the elongated case, it is necessary to place the electrode body 83 in the case 82 in the vertical direction. Therefore, since it is necessary to insert the electrode body 83 into the hole having a small opening area, there is a problem that it is difficult to assemble the electrode body 83 into the case 82.

  An object of the present invention is to provide a power storage device, a battery insulating member, and a vehicle that can ensure insulation between a case and an electrode body and can be easily assembled with the case and the electrode body. .

  In order to solve the above-mentioned problem, in claim 1, a rectangular parallelepiped case having an opening on either the surface having the largest area or the surface opposite to the surface having the largest area, and the case from the opening to the case An electrode body housed therein, and a thin-film insulating member that insulates the case and the electrode body, the insulating member adjacent to the surface having the opening in the electrode body; The gist is that it is attached to the surface opposite to the surface having the opening and the surface facing the surface.

  According to the configuration of the present invention, since it is possible to cover almost the entire electrode body with the insulating member, it is possible to ensure insulation between the electrode body and the case. The case has an opening formed on one of the surface having the largest area or the surface opposite to the surface having the largest area, and the electrode body is accommodated in the case from the opening. Therefore, the electrode body can be assembled to the case by easy positioning by inserting the electrode body through a hole having a large area.

As a definition, the “rectangular case” includes, in a broad sense, a shape having round corners in addition to a shape having a corner (R shape).
According to claim 2, in the invention according to claim 1, the electrode body includes a plurality of layers including a positive electrode, a negative electrode, and a separator that insulates the positive electrode and the negative electrode, and the insulating member includes the opening. Formed by bundling a first insulating member attached to a surface adjacent to the surface having a surface and a surface facing the surface having the opening, and an uncoated portion to which the active material layer is not applied in the positive electrode and the negative electrode. And a second insulating member that covers the current collector. According to this configuration, since it is possible to insulate the periphery of the electrode body over a wide range, the effect of securing insulation between the case and the electrode body is enhanced.

  According to a third aspect of the present invention, in the invention according to the second aspect, the first insulating member is a film member, the second insulating member is a tape member, and the first insulating member is the second insulating member. The gist is that it is attached and fixed to the electrode body by a member. According to this configuration, for example, the first insulating member may be a mere film member, so that the effect of reducing the component cost is enhanced.

  According to a fourth aspect of the present invention, in the invention according to the second or third aspect, the current collector is summarized on one surface of the electrode body. According to this configuration, since the current collector is concentrated on one surface, that is, current is collected in one direction, all the other surfaces of the electrode body can be simply flat. Therefore, the shape of the insulating member is not complicated.

  According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the current collector includes a positive electrode current collector and a negative electrode current collector, and the positive electrode current collector and the negative electrode current collector. The section is arranged in the same direction with respect to the electrode body, and the current collector is arranged on the upper surface of the electrode body. According to this configuration, the electrode terminals extending from the positive and negative current collectors can be easily pulled out from the upper part of the case without routing the wiring.

  In Claim 6, in the invention as described in any one of Claims 1-5, it has taken the open state before attachment, and when accommodated in the said case, along the said opening part of the said case The gist of the invention is that it includes a bent portion that takes a shape that encloses the electrode body by closing. According to this configuration, since the insulating member can be attached to the electrode body in the process of housing the electrode body in the case, assembly work can be simplified.

  According to claim 7, the insulation between the case having an opening in one of the surface having the largest area or the surface opposite to the surface having the largest area and the electrode body housed in the case from the opening. A thin film battery insulation member to be secured, wherein the electrode body is attached to a surface adjacent to the surface having the opening and a surface opposite to the surface opposite to the surface having the opening. The gist.

  The gist of the present invention is a vehicle including the power storage device according to any one of the first to sixth aspects.

  According to the present invention, it is possible to ensure insulation between the case and the electrode body, and it is also possible to easily assemble the case and the electrode body.

The disassembled perspective view of the secondary battery of one Embodiment. The perspective view which shows the external appearance of a secondary battery. The disassembled perspective view which shows the component of an electrode body. The top view of the insulating film before bending. Explanatory drawing which shows a mode that an insulating film is attached to an electrode body. Explanatory drawing which shows a mode that an insulating tape is affixed on an electrode body. Sectional drawing of the electrode body which attached the insulating film and the insulating tape. Explanatory drawing which shows a mode that an electrode body is accommodated in a case main body. Explanatory drawing which shows a mode that a case main body is closed with a case lid. The top view of the insulating film of another example. The disassembled perspective view which shows the structure of the conventional secondary battery.

Hereinafter, an embodiment of a power storage device, a battery insulating member, and a vehicle embodying the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, for example, in a vehicle 1 (shown in FIG. 2) such as a hybrid vehicle or an EV vehicle, a secondary battery 2 is mounted as a power source of a motor used as a drive source of the vehicle 1. . For example, a rectangular parallelepiped (flat) metal case 3 is provided in the secondary battery 2, and an electrode body 5, which is a power generation element, is accommodated inside the case body 4. In the rectangular parallelepiped case 3, an opening 4 a that serves as a storage opening for the electrode body 5 is formed on the side surface 3 a that is the largest surface. The opening 4 a is closed in a sealed state by a plate-like case lid 6.

  As shown in FIG. 2, a positive electrode terminal 7 that is a positive electrode terminal and a negative electrode terminal 8 that is a negative electrode terminal are provided on the upper surface of the secondary battery 2. The positive terminal 7 and the negative terminal 8 are exposed to the outside from the opening hole 4 c in the upper wall 4 b of the case body 4. Ring-shaped insulating components 9 that insulate the positive terminal 7 and the negative terminal 8 from the case 3 are respectively attached between the positive terminal 7 and the negative terminal 8 and the upper wall 4b.

  As shown in FIG. 3, the electrode body 5 includes a thin positive electrode sheet 10 serving as a positive electrode, a thin negative electrode sheet 11 serving as a negative electrode, and a separator 12 interposed between the positive electrode sheet 10 and the negative electrode sheet 11. It consists of an assembly having a plurality of sets (layers). Thus, the electrode body 5 of this example has a stacked structure in which the sheet group of the positive electrode sheet 10, the negative electrode sheet 11, and the separator 12 is stacked in a certain direction (stacking direction: Y-axis direction in FIG. 1 and the like). In addition, it is also possible to put electrolyte solution between each layer. The positive electrode sheet 10 and the negative electrode sheet 11 are actually made of very thin film members. Then, several tens of these are laminated, and the interval between the adjacent separators 12 is set to about 100 to 160 μm. The positive electrode sheet 10 and the negative electrode sheet 11 constitute an electrode.

  As shown in FIG. 3, a positive electrode active material layer 14 is applied to both surfaces of a metal sheet-like foil 13 on both surfaces of the positive electrode sheet 10, and this portion is formed as a coating portion 15. A part of the foil 13 is drawn out as a tab on a part of the periphery of the positive electrode sheet 10, and this part is formed as an uncoated part 16 where the positive electrode active material layer 14 is not applied. On both surfaces of the negative electrode sheet 11, a negative electrode active material layer 18 is applied on both surfaces of a metal sheet-like foil 17, and a coated portion 19 and an uncoated portion 20 are formed in the same manner as the positive electrode sheet 10.

  As illustrated in the circle of FIG. 3, the positive electrode sheet 10 and the negative electrode sheet 11 are each bundled with uncoated parts 16 and 20 having the same polarity in the stacking direction Y, thereby collecting current collecting parts 21 and 20, respectively. 22 is formed. In this example, the positive electrode side is the positive electrode current collector 21, and the negative electrode side is the negative electrode current collector 22. The current collectors 21 and 22 are arranged at positions close to the ends on the same surface (the upper surface in this example) of the electrode body 5. Therefore, the electrode body 5 of the present example has a shape in which the pair of current collecting portions 21 and 22 protrudes in a tab shape from the upper surface 23f of the electrode pair 23 which is the main body portion of the electrode body 5.

  Metal leads 24 and 25 are attached and fixed to the current collectors 21 and 22 as current paths. In this example, the positive electrode side is the positive electrode lead 24 and the negative electrode side is the negative electrode lead 25. The leads 24 and 25 are fixed to the current collectors 21 and 22 by, for example, resistance welding. The positive terminal 7 is attached and fixed to the positive lead 24, and the negative terminal 8 is attached and fixed to the negative lead 25. The uncoated portions 16 and 20 are firmly fixed to the leads 24 and 25 by resistance-welded portions 26 and 27.

  As shown in FIG. 1, the electrode body 5 is similarly formed in a rectangular parallelepiped according to the shape of the rectangular parallelepiped case 3. Therefore, the electrode body 5 includes a large-area front surface 23a and a back surface 23b that have a substantially rectangular shape, and a small-area right-side surface 23c and a left-side surface 23d that are elongated in the height direction of the electrode body 5 (the Z-axis direction in FIG. 1). The electrode body 5 has a total of six surfaces, that is, a back surface 23e having a small area elongated in the width direction (X-axis direction in FIG. 1) and an upper surface 23f. In addition, 23a, 23c, 23d, and 23e correspond to the surface adjacent to the surface which has an opening part, and the surface which opposes the surface opposite to the surface which has an opening part corresponds to 23b.

  As shown in FIGS. 1, 4 and 5, the electrode pair 23 is attached to the metal case 3 on all five surfaces of the front surface 23 a, the back surface 23 b, the right side surface 23 c, the left side surface 23 d and the back surface 23 e of the electrode pair 23. A thin insulating film 28 for insulation is attached. As the insulating film 28, for example, a sheet-like resin material (for example, polyester, polyethylene, or the like) film is used, and has a bottomed box shape with an open top surface. The insulating film 28 includes a first film surface 28a covering the front surface 23a of the electrode pair 23, a second film surface 28b covering the back surface 23b of the electrode pair 23, and a third film surface 28c covering the right side surface 23c of the electrode pair 23. The fourth film surface 28d covering the left side surface 23d of the electrode pair 23 and the fifth film surface 28e covering the back surface 23e of the electrode pair 23 are provided. The insulating film 28 corresponds to a first insulating member (film member, battery insulating member), and the third film surface 28c and the fourth film surface 28d constitute a bent portion.

  As shown in FIG. 4, the insulating film 28 is formed into a bottomed box shape by bending one sheet originally along the outer shape of the electrode pair 23. In the insulating film 28 of this example, the third film surface 28c is connected to the right side of the second film surface 28b, the fourth film surface 28d is connected to the left side of the second film surface 28b, and below the second film surface 28b. The first film surface 28a is connected to the side through the fifth film surface 28e. The insulating film 28 has fold lines 29 formed at the joints between the film surfaces 28a to 28e.

  As shown in FIGS. 6 and 7, an insulating tape 30 that insulates the current collectors 21 and 22 from the case 3 is attached to the upper part of the electrode pair 23. The insulating tape 30 is made of a sheet-like resin material (for example, polyester or polyethylene), and the back surface is an adhesive layer. The insulating tape 30 is bonded to the electrode pair 23 by bonding one end edge 30a to the first film surface 28a of the insulating film 28 and bonding the other end edge 30b to the second film surface 28b of the insulating film 28. The aligned insulating film 28 is fixed to the electrode pair 23. The insulating tape 30 corresponds to a second insulating member (tape member).

Next, the manufacturing process of the electrode body 5 of this example is demonstrated using FIGS.
First, as shown in FIG. 5, a single sheet-like insulating film 28 is prepared, and the insulating film 28 is assembled so as to be wrapped in the electrode pair 23. The insulating film 28 is positioned on the electrode pair 23 by bending along the broken line 29. At this time, the first film surface 28a contacts the front surface 23a of the electrode pair 23, the second film surface 28b contacts the back surface 23b of the electrode pair 23, and the fifth film surface 28e contacts the back surface 23e of the electrode pair 23. Abutted. At this time, the third film surface 28c and the fourth film surface 28d of the insulating film 28 are still open to the outside.

  Subsequently, as shown in FIGS. 6 and 7, the sheet-like insulating tape 30 is attached to the electrode body 5 so as to completely cover at least the current collecting portions 21 and 22. In the case of this example, with the current collectors 21 and 22 positioned inside the insulating tape 30, one end edge 30a of the insulating tape 30 is attached to the edge of the first film surface 28a, and the other end edge 30b is attached to the edge of the second film surface 28b. Thereby, the insulating film 28 is fixed to the electrode body 5 by the insulating tape 30.

  After the insulating tape 30 is attached, the electrode body 5 to which the insulating film 28 and the insulating tape 30 are attached is housed in the case body 4 as shown in FIG. In the case of this example, since the opening 4a of the case body 4 is located on the side surface 3a, the electrode body 5 is laterally inserted into the case body 4 from the side. At this time, in the process of housing the electrode body 5 in the case main body 4, the third film surface 28c and the fourth film surface 28d of the insulating film 28 are pressed by the side walls 4d of the case main body 4 to be bent and closed. . Then, as shown in FIG. 9, the case lid 6 is attached to the case body 4 to complete the assembly of the secondary battery 2.

  As described above, in this example, the current collecting structure of the rectangular parallelepiped electrode body 5 is a structure in which both current collecting portions 21 and 22 are arranged on one side of the electrode pair 23, and the entire circumference of the electrode pair 23 is insulated. Since it is covered with the film 28 and the insulating tape 30, insulation between the electrode body 5 and the case 3 is ensured. For this reason, since it is not necessary to provide an insulating space between the electrode body 5 and the case 3, it is highly effective in securing the energy density of the secondary battery 2, and further contributes to downsizing of the case 3. To do.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) A front surface 23a, a back surface 23b, a right side surface 23c, a left side surface 23d and a back surface 23e of the electrode pair 23 are covered with a single insulating film 28, and an insulating tape 30 having an adhesive surface is paired with a current collector. The insulating film 28 is fixed to the electrode body 5 by being attached to both ends of the insulating film 28 so as to completely cover the portions 21 and 22. Therefore, since the five surfaces (front surface 23a, back surface 23b, right side surface 23c, left side surface 23d and back surface 23e) of the electrode body 5 are covered with the insulating film 28, insulation between the case 3 and the electrode body 5 can be ensured. . Further, since the opening 4a is formed in the side surface 3a in the case 3 of the rectangular parallelepiped, and the electrode body 5 is laterally inserted through the opening 4a, the electrode body 5 can be easily positioned by inserting the electrode body 5 through a hole having a large area. The body 5 can also be assembled to the case 3.

  (2) Since the electrode body 5 can be placed in the case 3 along the stacking direction Y of the positive electrode sheet 10, the negative electrode sheet 11, and the separator 12, the electrode body 5 can be accommodated in the case 3 without deviation.

  (3) The periphery of the electrode pair 23 is covered with the insulating film 28, and the pair of current collectors 21 and 22 are covered with the insulating tape 30. For this reason, since it is possible to insulate the periphery of the electrode body 5 over a wide range, it is more effective in securing insulation between the case 3 and the electrode body 5.

  (4) The insulating film 30 is attached and fixed to the electrode body 5 by sticking the insulating tape 30 to both ends of the upper portion of the insulating film 28. Therefore, since it is not necessary to use a member having an adhesive layer as the insulating film 28, it is highly effective in reducing the component cost for the insulating film 28.

  (5) Since the positive and negative current collectors 21 and 22 are concentrated on one surface of the electrode body 5, that is, the current is collected in one direction, all the other surfaces of the electrode body 5 should be made simple planes. it can. Therefore, the insulating film 28 may have a simple shape that is not affected by the presence of the current collectors 21 and 22.

  (6) Since the current collectors 21 and 22 are centrally arranged on the upper surface 23f of the electrode pair 23, the positive and negative electrodes extending from the current collectors 21 and 22 are easily pulled out to the upper part of the case 3 without routing the wires. be able to.

  (7) When the insulating film 28 is attached to the electrode pair 23, the left and right film surfaces 28c, 28d are in an open state where they do not contact the electrode body 5, and in the process of housing the electrode body 5 in the case 3, By being guided to the periphery of the opening 4a, the left and right film surfaces 28c and 28d are closed to cover the electrode body 5. Therefore, when the electrode body 5 is housed in the case 3, the left and right film surfaces 28c, 28d of the insulating film 28 can be automatically bent, and the assembling work can be simplified.

(8) Since the folding line 29 is provided on the insulating film 28, the insulating film 28 can be easily folded according to the shape of the electrode pair 23.
(9) The insulating film 28 before bending was formed into a sheet shape having a third film surface 28c and a fourth film surface 28d on the left and right ends of the second film surface 28b. For this reason, when the insulating film 28 having a required shape is formed from one film sheet by cutting or punching, it is possible to reduce the portion to be discarded, and thus it is possible to reduce the yield.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
-The shape of the insulating film 28 is not limited to the shape which takes the shape shown in FIG. For example, as shown in FIG. 10, for example, a single rectangular sheet may be formed, and a pair of cuts 41 may be provided at a position closer to the center in the vertical direction of the paper surface. In short, the shape of the insulating film 28 can be appropriately changed according to use. This also applies to the insulating tape 30.

The opening 4 a serving as the storage opening for the electrode body 5 is not limited to being formed on the front surface (side surface 3 a) of the case, and may be formed on the back surface of the case 3, for example.
The arrangement position of the current collectors 21 and 22 is not limited to the upper surface 23 f of the electrode pair 23. For example, it can be changed to other positions such as the right side surface 23c and the left side surface 23d of the electrode pair 23.

  The current collectors 21 and 22 are not limited to a structure that collects current in one direction (one-way current collector structure). For example, the current collector 21 is arranged on the left side 23d and the current collector 22 is placed on the right side 23c. It may be arranged on separate surfaces, such as.

-The positive electrode current collection part 21 is not limited to one, For example, multiple may be sufficient and these may be electrically connected by one or several lead | read | reeds. The same can be said for the negative electrode current collector 22.
The current collectors 21 and 22 are not limited to the structure described in the embodiment, and can be appropriately changed to other structures.

The first insulating member is not limited to the insulating film 28 and may be an insulating tape having an adhesive surface.
The second insulating member is not limited to the insulating tape 30 and may be a simple insulating film having no adhesive surface.

-A welding location may be any location as long as the uncoated portions 16 and 20 are bundled.
-Various types of welding such as spot welding, butt welding, and projection welding can be used for resistance welding. Further, the welding is not limited to resistance welding, and other methods can be adopted.

The joining of the leads 24 and 25 and the current collecting parts 21 and 22 is not limited to welding, and other methods such as adhesion and welding can be adopted.
The third film surface 28 c and the fourth film surface 28 d of the insulating film 28 may already be in contact with the electrode pair 23 before the electrode body 5 is attached to the case 3.

The fold line 29 may be omitted.
-The raw material of the positive electrode sheet 10, the negative electrode sheet 11, and the separator 12 can be changed suitably.

-A bending part is not limited to the 3rd film surface 28c and the 4th film surface 28d, Depending on the shape of the insulating film 28, it is also possible to apply to the 5th film surface 28e.
The insulating member does not require both the insulating film 28 and the insulating tape 30, and it is sufficient that the insulating member includes at least the insulating film 28.

The power storage device is not limited to a secondary battery, and may be an electric double layer capacitor using a nonaqueous electrolyte capacitor (nonaqueous electrolyte capacitor), for example.
The electrode body 5 is not limited to being mounted on the vehicle 1 and can be mounted on other devices and apparatuses.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Battery (secondary battery), 3 ... Case, 3a ... Side surface, 4a ... Opening part, 5 ... Electrode body, 10 ... Positive electrode sheet which comprises an electrode, 11 ... Negative electrode sheet which comprises an electrode, 12 ... Separator, 16, 20 ... Uncoated part, 21,22 ... Current collecting part, 23 ... Electrode pair, 23a ... Front face, 23b ... Back face, 23c ... Right side face, 23d ... Left side face, 23e ... Back face, 23f ... Top face 28 ... Insulating film as a first insulating member (film member, battery insulating member), 28c ... Third film surface constituting a bent portion, 28d ... Fourth film surface constituting a bent portion, 30 ... Second insulation Insulating tape as a member (tape member).

Claims (8)

A rectangular parallelepiped case having an opening on either the surface having the largest area or the surface opposite to the surface having the largest area;
An electrode body housed in the case from the opening;
A thin-film insulating member for insulating the case and the electrode body;
The power storage device, wherein the insulating member is attached to a surface of the electrode body adjacent to the surface having the opening and a surface opposite to a surface opposite to the surface having the opening. The electrode body has a plurality of layers composed of a positive electrode, a negative electrode, and a separator that insulates the positive electrode and the negative electrode,
The insulating member is
A first insulating member attached to a surface adjacent to the surface having the opening and a surface facing the surface having the opening;
2. The power storage device according to claim 1, further comprising: a second insulating member that covers a current collector formed by bundling an uncoated portion to which an active material layer is not applied in the positive electrode and the negative electrode. . The first insulating member is a film member, and the second insulating member is a tape member,
The power storage device according to claim 2, wherein the first insulating member is attached and fixed to the electrode body by the second insulating member. 4. The power storage device according to claim 2, wherein the current collecting unit is arranged in a concentrated manner on one surface of the electrode body. 5. The current collector includes a positive current collector and a negative current collector, the positive current collector and the negative current collector are disposed in the same direction with respect to the electrode body, and the current collector is It is arrange | positioned at the upper surface of an electrode body, The electrical storage apparatus as described in any one of Claims 2-4 characterized by the above-mentioned. It is open before mounting, and includes a bent portion that takes a shape that encloses the electrode body by closing along the opening of the case when housed in the case. The electrical storage apparatus as described in any one of Claims 1-5. A thin film that ensures insulation between the case having an opening on one of the surface having the largest area or the surface opposite to the surface having the largest area and the electrode body housed in the case from the opening. A battery insulation member comprising:
The battery insulating member, wherein the electrode body is attached to a surface adjacent to the surface having the opening and a surface opposite to the surface opposite to the surface having the opening. A vehicle comprising the power storage device according to claim 1.