JP2005116437A - Packed battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packed battery prevented from damage and deterioration caused by the vibration of a connecting part connecting an electrode tab with the other electrode tab of the battery. <P>SOLUTION: The packed battery is provided with a plurality of laminated single cells 200, heat sinks 250 holding the plurality of single cells from both sides, connecting parts 102 each connecting the electrode tab with the other electrode tab of the single cell, and a bracket 103 fixing the connecting parts 102 to the heat sinks 250. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an assembled battery.

  In recent years, in response to growing environmental awareness, there is a movement to shift the power source of automobiles from an engine using fossil fuel to a motor using electric energy. For this reason, the technology of the battery that serves as a power source for the motor is also rapidly developing.

  An automobile is desired to be equipped with a battery that is small and light and can be charged and discharged with a large amount of electric power and has excellent vibration resistance and heat dissipation. As an assembled battery excellent in heat dissipation capable of supplying large electric power, there is a battery as shown in Patent Document 1 below.

An assembled battery disclosed in Patent Document 1 includes a plurality of flat unit cells that are electrically connected in series, parallel, or series-parallel, arranged at predetermined intervals in the thickness direction of the unit cells, A pressing member that presses the unit cells on both sides is arranged on the side, and a plurality of unit cells are fixed by an exterior member. By adopting such a structure, the heat dissipation characteristics of the single battery are improved, and the cycle characteristics and rate characteristics of the assembled battery are improved.
JP 2000-195480 A (see paragraph numbers “0014” to “0029” and the descriptions of FIGS. 1, 2, and 4)

  In such an assembled battery, it is conceivable to connect the electrode tabs that are connected to each other when the individual cells are connected in series, for example, by fastening them with bolts and nuts via a bus bar.

  Since the connection portion in which the electrode tabs are bolted with bolts and nuts in this way is supported by the electrode tabs of each unit cell, when the vibration is applied to the assembled battery itself, the connection portion is Only the portion vibrates separately from the entire assembled battery due to the mass of the connecting portion such as the nut.

  Such a vibration phenomenon in the connection portion causes deterioration or breakage of the electrode tab.

  Accordingly, an object of the present invention is to provide an assembled battery in which a connection portion connecting electrode tabs of the battery is not damaged or deteriorated by vibration.

  The assembled battery of the present invention includes a plurality of stacked unit cells, holding means for holding the plurality of unit cells, at least one electrode tab of the unit cell, and one of the other unit cells. It has a connection part which connects an electrode tab, and a fixing means which fixes the connection part to the holding means.

  In the present invention, since the connection portion that connects the electrode tabs of the plurality of stacked unit cells is fixed to the holding unit that holds the entire assembled battery using the fixing unit, even when vibration is applied to the assembled battery. It can prevent that a connection part vibrates separately from the whole assembled battery.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  1 is an overall perspective view of an assembled battery to which the present invention is applied, FIG. 2 is an enlarged perspective view of a main part, FIG. 3 is a plan view of one layer of the assembled battery, and FIG. It is a fragmentary sectional view which follows the AA line shown in FIG.

  The assembled battery 100 includes an assembled battery main body 101 in which a plurality of flat unit cells 200 are stacked, and a bracket 103 that fixes and supports a battery vertical connection portion 102 in the assembled battery main body 101.

  In the assembled battery main body 101, a plurality of flat unit cells 200 arranged on one plane are connected in series by the first bus bar 201 (see FIG. 3), and the plurality of flat unit cells connected in series are connected. 200 is further stacked, and all the cells 200 are connected in series by connecting up and down at the end.

  The flat unit cell 200 is a so-called thin battery formed in a flat type, and has a flat shape with a width and length in a direction perpendicular to the stacking direction larger than the thickness in the stacking direction. doing. The unit cell 200 is a secondary battery including a plurality of power generation elements (not shown) in which a positive electrode plate, a negative electrode plate, and a separator are sequentially stacked. The internal power generation element is, for example, a lithium ion secondary battery. Hereinafter, the flat unit cell is simply referred to as a unit cell.

  The single battery used here is a laminated battery covered with a three-layer laminated film. The laminate film is formed in three layers with an aluminum foil sandwiched between resin films such as polyamide resin. One of the two laminated films is formed into a flat shape by pressing, and is bonded to the other sheet in the form of a sheet by thermal fusion at the edge.

  In the laminated battery, the power generation element is sealed using such a laminated film, and the positive electrode tab 202 and the negative electrode tab 203 are drawn out as electrodes in a direction perpendicular to the stacking direction of the flat unit cells.

  As described above, the assembled battery is obtained by connecting the single cells in series in the horizontal direction for one layer, and further stacking a plurality of batteries having this layer structure.

  As shown in FIG. 3, the plurality of unit cells 200 constituting one layer are configured such that the positive electrode tab 202 and the negative electrode tab 203 which are electrodes of the plurality of unit cells 200 (here, five unit cells 200) are first to each other. The bus bars 201 are joined by welding and connected in series.

  As shown in FIG. 4, the connecting portion 102 that connects the layers in series in the vertical direction is connected to the electrode tabs 202 and 203 of the unit cells 200 at both ends of the plurality of unit cells 200 having the layer structure described above. The bus bar 121 is joined, and the second bus bar 121 is fastened by a bolt 122 and a nut 123. Note that the electrode tab 202 (or 203) and the second bus bar 121 have one 121a (or 121b) of the second bus bars 121 bolted to the electrode tab 202 (or 203) in advance as a pair. They are joined by welding or soldering.

  The assembled battery main body 101 shown in the figure is composed of, for example, 10 layers, and the middle layer (in FIG. 2, the third layer and the fourth layer, the fifth layer and the sixth layer on the illustrated side). Eyes, and 7th and 8th layers, 2nd and 3rd layers, 4th and 5th layers, 6th and 7th layers, The eighth layer and the ninth layer) are connected by bolt fastening. On the other hand, in the case of illustration, the outermost layer and the next layer have a U-shape on the electrode tabs in the first and second layers, and in the ninth and tenth layers. The bus bars are directly welded or the electrode tabs are joined directly to each other.

  This is because the outermost layer is joined by welding because there is a space for welding with a welder, but the middle layer is bolted because the electrode tabs overlap and the welder does not enter, so welding is not possible. is there.

  The stacked unit cells 200 are held by two outer layer heat sinks 250 from above and below. The outer layer heat sink 250 is a part of the holding means, is supported by the pressure unit 240, and plays a role of applying a certain surface pressure to each of the stacked unit cells 200.

  In addition, the outer layer heat sink 250 is configured by stacking two plate-like members having recesses so that the recesses face each other, and the opposing recesses serve as air circulation holes 256, thereby improving the cooling efficiency. It is improving. In this embodiment, the heat sink is formed by the two plate-like members having the concave portions as described above, but may be formed as a single member by, for example, extrusion molding.

  Further, an inner layer heat sink 251 is further provided between the layers of the stacked unit cells 200. Similarly to the outer layer heat sink, the layer heat sink 251 is configured by stacking two plate-like members having recesses 6 so that the recesses face each other. , Improving the cooling efficiency.

  The holding means includes an outer layer heat sink 250 that is a plate-like member and a pressurizing unit 240 that is disposed between the outer layer heat sinks 250 and connects the outer layer heat sinks 250.

  FIG. 5 is a diagram showing the pressurizing unit, FIG. 5A is a diagram showing the overall configuration of the pressurizing unit, and FIG. 5B is a diagram showing the configuration of the spring holding portion. 6 is a cross-sectional view of the pressure unit, FIG. 6 (A) is a diagram showing an initial state of the pressure unit, and FIG. 6 (B) shows a state where the pressure unit is attached between the outer layer heat sinks. FIG.

  The pressure unit 240 includes a tension coil spring 242 (elastic body) and spring holding portions 243 that hold both ends of the tension coil spring 242.

  The tension coil spring 242 is attached between the outer layer heat sinks 250 in a stretched state, thereby acting to contract and expressing an elastic force in a direction to bring the outer layer heat sinks 250 closer to each other.

  The spring holding portion 243 includes a main body portion 244, a screwing portion 245 having a thread formed at a pitch P2 larger than the pitch P1 of the tension coil spring 242, and a butt extending from the screwing portion 245 toward the center of the tension coil spring 242. Part 246 and an insertion part 247 extending from main body part 244 and inserted through heat sink 2a.

  The main body 244 abuts against the tension coil spring 242 so that it does not come off. The main body 244 also contacts the heat sink 2a when the pressure unit 240 is attached to the assembled battery, and also plays a role of determining the extension of the tension coil spring 242.

  As shown in the figure, the screwing portion 245 is screwed into the end portion of the tension coil spring 242, screwed into the inside of the tension coil spring 242, and fixed thereto. As shown in FIG. 5B, the threaded portion 245 has a thread having a pitch P2 formed on the surface thereof. The pitch P <b> 2 of the screwing portion 245 is larger than the pitch P <b> 1 of the tension coil spring 242. Therefore, the screwing portion 245 can be screwed in the direction of the arrow in FIG. By screwing the screwing portion 245, the butting portion 246 advances toward the center of the tension coil spring 242.

  When the screwing portion 245 is screwed in from both ends of the tension coil spring 242, the butting portions 246 that have advanced from both sides come into contact with each other as shown in FIG. In this state, the tension coil spring 242 is extended from its natural length, and an initial tension is applied as an initial state of the pressure unit 240.

  The insertion portion 247 has a thread that can be fastened to the nut 241 at the tip. A slit 248 for preventing rotation described later is provided at the head of the insertion portion 247. The spring holding portion 243 can be easily prevented from rotating by inserting a flathead screwdriver into the slit 248.

  When such a pressure unit 240 is arranged between the outer layer heat sinks 250, it is as shown in FIG.

  Here, the insertion portion 247 is inserted into the hole 222 of the outer layer heat sink 250. In this state, the insertion portion 247 of the other spring holding portion 243 is fastened with the nut 241 while preventing the one spring holding portion 243 from rotating. Then, the spring holding part 243 is pulled toward the nut 241 side. When this is performed by both spring holding portions 243, the spring holding portion 243 is relatively separated while holding the tension coil spring 242, as shown in FIG. 6B, and the tension coil spring 242 is interposed between the outer layer heat sinks 250. It is held in a stretched state.

  In this manner, the tension coil spring 242 is stretched in accordance with the width between the outer layer heat sinks 250, so that an elastic force in the contracting direction by the tension coil spring 242 is obtained regardless of the tightening torque of the nut 241. The elastic force is applied to the unit cell by the outer layer heat sink 250.

  Next, the bracket 103 is a fixing means for preventing the connection portion 102 from vibrating.

  The bracket 103 includes a bracket body portion 132 having a window portion 131 into which the connection portion 102 is inserted, a taper portion 133 that positions the bracket body portion 132 and fixes the bracket body portion 132 to the assembled battery 100, and the connection portion 102 in the window portion 131. It consists of the adhesive 135 (refer FIG. 4) as a fixing material for fixing to the bracket main-body part 132. FIG. In FIGS. 1 and 2, the adhesive 135 is not shown for easy understanding of the window 131 and the structure therein.

  The bracket main body portion 132 is a main body portion for fixing means, and a window portion 131 into which the connection portion 102 is inserted is formed. In the example shown in the figure, the window portions 131 are alternately arranged so that the connection portions 102 on one side do not interfere with each other, and therefore the window portions 131 are opened in accordance with these connection portions 102.

  The size of the opening of the window portion 131 is slightly larger than the length L of the bolt 122 of the connection portion 102 in order to cope with the position variation of the connection portion 102. Since the assembled battery body 101 is composed of a plurality of layers as described above, the position variation of the connection portion 102 is caused by subtle variations in shape due to manufacturing variations of individual unit cells 200 and the like. This occurs because it differs for each assembled battery main body 101. For example, when the displacement of the connecting portion 102 is about 0.1 to 1 mm, the size of the opening of the window portion 131 is further 0. 0 than the length L of the bolt 122 fastening the connecting portion 102. It is good to form large about 5-2 mm.

  Further, as shown in FIG. 4, the bracket main body part 132 is partially cut at one end, and this part (referred to as a taper cut part 137) contacts a taper part 133 described later. The side with the taper cut portion does not contact the outer layer heat sink 250. On the other hand, the other end 138 has an L-shaped cross section so as to contact the outer layer heat sink 250 of the assembled battery main body 101.

  Further, the taper surface of the taper cut portion 137 has a smooth surface so that the friction coefficient is increased.

  The taper portion 133 has a taper cut on the side 141 that abuts the taper cut portion of the bracket main body portion 132, and the other end portion 142 abuts on the outer layer heat sink 250 of the assembled battery main body portion 101. The tapered surface of the tapered portion 133 is also smoothed so that the friction coefficient is increased. The taper part 133 is prevented from dropping after the taper part 133 is inserted by the taper surface having a smoothed surface. The surface of the taper portion may be smoothed by surface processing, and the bracket main body portion 132 and the taper portion 133 may be bonded with an adhesive.

  Therefore, even if the length h between the outer layer heat sinks 250 of the assembled battery main body 101 changes slightly, the amount of the taper portion 133 entering changes according to the difference in the length h between the outer layer heat sinks 250, and the bracket main body 132 is Appropriately positioned and secured between outer layer heat sinks 250.

  The bracket main body portion 132 and the taper portion 133 are preferably insulating members in consideration of being disposed around the battery. As the insulating member, for example, a resin member such as epoxy resin, ABS resin, silicone resin, or ceramics can be used.

  The connection part 102 inserted into the window part 131 is fixed by an adhesive 135. This adhesive 135 is a fixing material, for example, an epoxy resin-based, synthetic rubber-based, silicone-based adhesive or the like. Of course, other adhesives may be used as long as the connection part 102 inserted into the window part 131 can be fixed in the window part.

  In this embodiment, the adhesive 135 is used as a fixing material for fixing the connecting portion 102. However, the present invention is not limited to this. For example, a spacer is provided between the inner surface of the window 131 and the connecting portion. The connecting portion may be fixed by inserting.

  As described above, according to the best mode for carrying out the present invention, since the connection portion 102 is fixed by the bracket 103 even when vibration is applied to the assembled battery 100, the connection portion 102 is determined by the mass of the connection portion 102. Can be prevented from vibrating separately from the assembled battery 100, and damage to the electrode tab and the connecting portion 102 due to vibration can be prevented. For example, this assembled battery 100 is suitable as a power source for a vibrating mechanical device such as an electric vehicle or a hybrid vehicle.

  Further, according to the present embodiment, the window 131 for actually fixing the connecting portion 102 is slightly larger than the size of the connecting portion 102 and is fixed by filling the inside with an adhesive. In the case of the battery 100, even if the same bracket 103 is used, it is possible to absorb the fluctuation of the position of the connection portion 102 due to the thickness variation of the individual single cells 200 and to fix the connection portion 102 to the bracket 103 with certainty.

  Further, according to the present embodiment, the bracket 103 is divided into the bracket main body part 132 and the taper part 133 and fixed between the outer heat sinks 250 of the assembled battery main body part 101. The bracket 103 can be reliably fixed between the outer layer heat sinks 250 of the assembled battery main body 101 by adjusting the amount of taper part 133 entering.

  Although the best mode for carrying out the present invention has been described above, the present invention is not limited to such a mode. For example, in the embodiment described above, a plurality of unit cells 200 are first connected in series in the lateral direction to form a layer structure, and this is further laminated to form the assembled battery body 101. Without being limited to the configuration of the assembled battery main body 101, in the assembled battery 100 having a portion where a plurality of unit cells 200 are connected, the connecting portion 102 can be fixed by the bracket 103. In this case, the form of the bracket 103 can be changed as appropriate according to the number and position of the connecting portions 102.

  In the best mode described above, the bracket 103 is divided into the bracket main body portion 132 and the taper portion 133. For example, the entire bracket main body portion 132 or only both end portions in contact with the outer layer heat sink 250 are made of silicone rubber. The taper portion 133 may be omitted by being formed of such an elastic material, and may be fitted and fixed between the sheet sinks by the elastic force of the elastic member.

  Furthermore, in the above-described best mode, when the cells are stacked, the cells are stacked in direct contact with each other (or with the inner layer heat sink). A high friction member such as a sheet may be interposed. When the assembled battery is assembled by interposing such a high-friction member, it is possible to prevent deviation due to the vibration of the unit cell.

  In the present embodiment, the connecting portion 102 is fixed to the heat sink 250 via the bracket 103. However, for example, when a case for housing the assembled battery 100 is provided, the connecting portion 102 may be fixed to this case.

  The assembled battery of the present invention is suitable, for example, as a power source for an electric vehicle, a hybrid vehicle, a fuel cell vehicle, etc., or as a power source mounted on a vibrating machine or device.

It is the whole assembled battery perspective view to which the present invention is applied. It is a principal part perspective view of the assembled battery to which this invention is applied. It is a top view for 1 layer of the assembled battery laminated | stacked. It is a fragmentary sectional view which follows the AA line shown in FIG. It is a figure which shows the whole structure of a pressurization unit. It is sectional drawing of a pressurization unit.

Explanation of symbols

100 ... assembled battery,
101 ... assembled battery body,
102, 102b, 102c, 102d, 102e ... connection part,
103 ... Bracket,
121 ... second bus bar,
122 ... Bolt,
123 ... Nut,
131 ... window,
132 ... bracket main body,
133: Tapered portion,
135 ... adhesive,
200 ... single cell,
201 ... 1st bus bar,
240 ... Pressure unit,
250 ... heat sink,
256: distribution hole.

Claims (8)

A plurality of unit cells stacked;
Holding means for holding the plurality of single cells;
A connecting portion for connecting one electrode of at least one unit cell and one electrode of the other unit cell;
Fixing means for fixing the connecting portion to the holding means;
An assembled battery comprising: The holding means has two plate-like members that sandwich the plurality of unit cells from both sides in the stacking direction,
2. The assembled battery according to claim 1, wherein the fixing means fixes the connection portion and is fixed to the holding means to fix the connection portion to the holding means. The fixing means includes a main body portion and a tapered portion,
The main body has a first inclined surface with one end abutting against one of the plate-shaped members and the other end inclined with respect to a surface orthogonal to the stacking direction of the unit cells. Without contacting the member
The tapered portion has a second inclined surface corresponding to the first inclined surface at one end, abuts against the first inclined surface of the main body, and the other end contacts the other of the plate-like member. The assembled battery according to claim 1, wherein the battery pack is in contact with the battery pack. The fixing means has a window portion larger than the connection portion into which the connection portion is inserted,
The assembled battery according to claim 1, wherein the connection portion is fixed by a fixing material in the window portion.   The two plate-like members are connected by an elastic member, and a force in a direction close to each other is applied by the elastic member to apply a constant surface pressure in the stacking direction to the plurality of unit cells. The assembled battery according to claim 2.   The assembled battery according to claim 2, wherein the plate-shaped member is a cooling unit that cools the unit cell. The connecting portion is a bus bar that is individually joined to the electrodes of at least two or more of the stacked unit cells, respectively.
The assembled battery according to any one of claims 1 to 6, further comprising: a bolt and a nut for fastening two or more bus bars joined to the electrodes of the two or more unit cells. The unit cell is a flat unit cell having a larger width and length in a direction perpendicular to the stacking direction than a thickness in the stacking direction,
The assembled battery according to any one of claims 1 to 7, wherein the electrode is an electrode tab protruding in a direction orthogonal to the stacking direction of the flat unit cells.

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