JP2008293662A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack of square batteries capable of pressurizing respective batteries uniformly and dissipating heat from the respective batteries efficiently. <P>SOLUTION: The plurality of square batteries 2 in which a positive electrode terminal 4 and a negative electrode terminal 5 are taken out from the same side are arranged radially so that the positive electrode terminal 4 and the negative electrode terminal 5 are positioned inside. A wedge form spacer 3 is installed respectively between the respective batteries 2 so that its tip 3a is positioned inside, and by pressurizing the respective spacers 3 toward inside, the respective batteries 2 are pressurized. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an assembled battery that can pressurize and hold a plurality of prismatic batteries.

  A battery pack in which a plurality of prismatic lithium ion batteries are stacked by laminating a plurality of electrode plates via a separator and housed in a laminate type exterior member and sealed has a large capacity and good high-rate characteristics. Therefore, it is used for robots, electric vehicles, backup power supplies, etc.

  In the laminate-type prismatic lithium ion battery as described above, the electrode plate expands and contracts during charging and discharging. When the distance between the electrode plates increases, the electron conductivity in the positive electrode active material layer and the negative electrode active material layer decreases, so that the internal resistance increases, resulting in a decrease in battery capacity and deterioration in cycle characteristics. Therefore, in an assembled battery in which prismatic lithium ion batteries are stacked, it is preferable to apply pressure to each battery from the outside so that the distance between the electrode plates does not increase.

  In Patent Documents 1 to 3, the laminate-type prismatic lithium ion battery as described above is laminated in the thickness direction via a plate or a spacer, and a restraint plate is provided at both ends of the laminated battery, and the restraint plate is attached to a belt or Each battery is pressed by tightening with a connecting rod.

  However, when each battery is pressed by such a method, there is a problem that it is difficult to apply a uniform pressure to each battery. In particular, when the number of stacked batteries is large, there is a problem that unevenness is easily generated in the pressure between the battery located at both ends and the battery near the center. For this reason, internal resistance rises in some batteries, which tends to cause a reduction in battery capacity and deterioration in cycle characteristics.

  In addition, each battery generates heat during high-rate discharge. However, in the conventional assembled battery structure, heat is not sufficiently released from each battery, and the battery rises in temperature and may reach a maximum operating temperature and cannot be discharged. .

In Patent Document 4, as in the present invention, a structure of a battery assembly in which batteries are arranged radially is disclosed, but such a radial arrangement of batteries is not for pressing each battery, It is for cooling each battery uniformly by the cooling passage formed in the center part of radial arrangement.
JP 2003-323874 A JP 2005-259500 A JP 2006-196222 A JP 2006-185778 A

  The objective of this invention is providing the assembled battery of the square battery which can pressurize each battery uniformly and can be thermally radiated from each battery efficiently.

  In the assembled battery of the present invention, a plurality of prismatic batteries in which the positive electrode terminal and the negative electrode terminal are taken out from the same side are arranged radially so that the positive electrode terminal and the negative electrode terminal are located inside, and a wedge-shaped spacer is provided between the batteries. Each of the batteries is provided so that the tip thereof is positioned inside, and each battery is pressed by pressing each spacer inward.

  In the present invention, a plurality of prismatic batteries are radially arranged so that the positive electrode terminal and the negative electrode terminal are located inside, and a wedge-shaped spacer is provided between each battery so that the tip thereof is located inside. Each battery is pressurized by pressing inward. For this reason, each battery can be pressurized by the spacers in substantially the same state. Therefore, each battery can be uniformly pressurized.

  In the present invention, wedge-shaped spacers are provided between the batteries, and the batteries are not closely stacked as in the prior art, so that heat can be efficiently radiated from the batteries. For this reason, charge and discharge at a high rate with a large capacity that could not be discharged due to a large temperature rise becomes possible.

  In this invention, it is preferable that the outer peripheral part of each spacer is located outside the outer edge part of each battery. By positioning the outer peripheral portion of each spacer outside the outer end portion of each battery, a belt can be wound around the outer peripheral portion of each spacer, the belt can be tightened, and each spacer can be pressed inward. According to such belt tightening, the spacers can be simultaneously pressed inward, and the batteries can be more uniformly pressed. Further, each battery can be pressed by tightening the belt, and each battery can be held via each spacer.

  Moreover, in this invention, each battery is radially arrange | positioned so that a positive electrode terminal and a negative electrode terminal may be located inside. For this reason, the batteries can be connected in series or in parallel by connecting the positive electrode terminal and the negative electrode terminal at the inner part of the radially arranged battery, that is, the central part of the assembled battery. Therefore, it is possible to connect the terminals using the space in the central portion of the assembled battery. Moreover, since the positive electrode terminal and the negative electrode terminal can be brought close to each other, the distance between the terminals can be shortened, the electric resistance between the terminals can be reduced, and the output of the entire assembled battery can be increased.

  Further, since the terminals arranged in the central portion are close to each other, the terminals can be directly connected to each other. For this reason, the lead wire etc. for connecting terminals are unnecessary. Since lead wires or the like are not required, the electrical resistance due to the connection between the terminals can be reduced, and the output of the entire assembled battery can be increased. In addition, since no lead wire or the like is used, electrical wiring is simplified, and no insulation measure is required when the lead wire is routed. Further, by directly connecting the terminals, the assembled structure of the assembled battery can be held more firmly.

  In the present invention, it is preferable that the pressurization surface of the spacer has a flat portion that is equal to or wider than the pressurized side surface of the battery. Since the pressing surface of the spacer has such a flat portion, the entire side surface of the battery can be uniformly pressed.

  In the present invention, the spacer is preferably made of metal. By forming the spacer from metal, the thermal conductivity of the spacer can be increased, and the heat generated from each battery can be radiated to the outside through the spacer more efficiently. As a metal, it is preferable that it is a metal with high heat conductivity, For example, metals, such as SUS (stainless steel), aluminum, copper, are mentioned. However, the material of the spacer of the present invention is not limited to metal, and may be formed using resin or the like.

  In the present invention, it is preferable that the spacer has a hollow structure. By using a hollow structure, the spacer can be reduced in weight. Moreover, it is more preferable that the spacer has a hollow structure with an open outer periphery. By adopting a hollow structure with an open outer periphery, heat generated from the battery can be efficiently radiated through the spacer.

  The prismatic battery in the present invention is preferably a battery in which a plurality of positive electrodes and negative electrodes are alternately stacked via separators. In such a stacked battery, the positive electrode tab connected to each positive electrode and the negative electrode tab connected to each negative electrode are taken out together, and the positive electrode tab is connected to the positive electrode terminal and the negative electrode tab is connected to the negative electrode terminal.

  The prismatic battery according to the present invention is a battery in which an electrode body composed of a positive electrode, a negative electrode, and a separator is inserted into an exterior body made of a flexible film such as a laminate film, and an electrolyte is injected into the exterior body. Is preferred.

  Further, the prismatic battery according to the present invention is an outer package made of a laminate film or the like, in which a positive electrode and a negative electrode are overlapped through a separator and wound into a spiral shape to form an electrode body. It may be produced by being inserted into the.

  The prismatic battery according to the present invention has opposed side surfaces to be pressurized. In the present invention, the inside of the battery is pressurized by pressing the side surfaces of the battery with the pressure surface of the spacer. By pressurizing the inside of the battery, an increase in the distance between the electrodes can be suppressed, and a decrease in battery capacity and a deterioration in cycle characteristics due to an increase in internal resistance can be suppressed.

  When a lithium ion battery having a laminate film as an outer package is used as the prismatic battery in the present invention, the effect of the present invention can be expected most remarkably. A lithium ion battery having a laminate film as an outer package is particularly easily swelled by charging / discharging, so that the effect of suppressing an increase in the distance between electrodes by pressurizing the battery is most prominent. For this reason, the effect of the present invention can be expected most remarkably. However, the present invention is not limited to this, and the exterior body is formed from a metal can or a resin case, or the battery system is another battery system such as a nickel cadmium battery or a nickel metal hydride battery. May be.

  According to the present invention, each battery can be pressurized by pressing the spacer between the batteries inward. Therefore, for example, by winding a belt around the outer periphery of the spacer and tightening the belt, the spacer can be pressed inward simultaneously, and each battery can be pressed almost uniformly. For this reason, it is possible to prevent unevenness in the pressure for pressurizing the battery as in the conventional case, and it is possible to pressurize each battery with a uniform pressure. Accordingly, the effect of suppressing the increase in the distance between the electrodes in each battery can be obtained to substantially the same extent, and the decrease in battery capacity and the deterioration in cycle characteristics can be suppressed.

  In the present invention, since the spacer is provided between the batteries, the heat generated from each battery during the high rate discharge can be efficiently released to the outside through the spacer. For this reason, high-rate charging / discharging becomes possible.

  Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to the following examples.

<Preparation of laminated laminate type square battery>
[Production of positive electrode]
90% by weight of LiCoO ₂ as a positive electrode active material, 5% by weight of carbon black as a conductive agent, 5% by weight of polyvinylidene fluoride as a binder, and N-methyl-2-pyrrolidone (NMP) as a solvent Were mixed to prepare a positive electrode mixture slurry, and this positive electrode mixture slurry was applied to both surfaces of an aluminum foil as a positive electrode current collector. Thereafter, the solvent was dried, compressed to a thickness of 0.1 mm with a roller, and then cut to a width of 95 mm and a height of 95 mm to produce a positive electrode.

In addition to the above LiCoO ₂ , for example, LiNiO ₂ , LiMnO _4, or a composite thereof may be used as the positive electrode active material.

[Production of negative electrode]
After preparing a negative electrode mixture slurry by mixing 95% by weight of graphite powder as a negative electrode active material, 5% by weight of polyvinylidene fluoride as a binder, and an NMP solution as a solvent, this slurry was mixed with the negative electrode collector. It apply | coated to both surfaces of the copper foil as an electric body. Thereafter, the solvent was dried and compressed to a thickness of 0.08 mm with a roller, and then cut to have a width of 100 mm and a height of 100 mm to produce a negative electrode.

  In addition, although artificial graphite is used as the negative electrode active material, natural graphite and other carbon materials are also preferably used.

[Attaching the current collector tab]
A positive electrode tab made of aluminum foil was attached to the positive electrode, and a negative electrode tab made of copper foil was attached to the negative electrode by ultrasonic welding.

[Production of laminated electrode body]
The positive electrode tab and the negative electrode tab attached with the positive electrode tab and the negative electrode 51 sheet attached with the negative electrode tab in the direction in which the positive electrode tab and the negative electrode tab are on the same side through a polypropylene separator (100 mm × 100 mm, thickness 30 μm). Laminated. In addition, the positive electrode and the negative electrode were laminated | stacked so that both ends might become a negative electrode. An insulating tape was wound around the laminated body to maintain the shape, thereby obtaining a laminated electrode body.

[Preparation of electrolyte]
Ethylene carbonate (EC) and methyl ethyl carbonate (MEC) were mixed at a volume ratio of 30:70, and dissolved in this mixed solvent so that LiPF ₆ was 1 M (mol / liter). An electrolytic solution was prepared.

[Production of laminated laminated battery]
The above laminated electrode body is inserted into an exterior body made of a laminate film, the sides of the exterior body on the side where the positive electrode tab and the negative electrode tab are attached are heat-sealed, and two of the remaining 3 sides are heated. Fused. Next, the electrolyte is injected into the exterior body from one side that is not thermally fused, and the exterior body is hermetically sealed by heat-sealing one side that is not thermally fused after the injection. A type battery was completed.

<Production of assembled battery>
Using the laminated laminate type battery produced above, an assembled battery was produced as follows.

Example 1
FIG. 1 is a plan view showing the assembled battery manufactured in Example 1. FIG. FIG. 2 is a perspective view showing the laminated laminate battery produced as described above.

  As shown in FIG. 2, a positive electrode terminal 4 and a negative electrode terminal 5 are attached to the laminated laminate type battery. The positive electrode terminal 4 is attached to the positive electrode tab of each positive electrode stacked in the battery 2 by ultrasonic welding. Similarly, the negative electrode terminal 5 is connected to the negative electrode tab of each negative electrode laminated in the battery 2 by ultrasonic welding.

  As shown in FIG. 2, the positive electrode terminal 4 has a straight portion 4a extending linearly from the battery 2 and a bent portion 4b bent from the end of the straight portion 4a, and a hole 4c is formed in the bent portion 4b. Is formed. Similarly, the negative electrode terminal 5 is also formed with a straight portion 5a and a bent portion 5b bent from the end of the straight portion 5a, and a hole 5c is formed in the bent portion 5b. As shown in FIG. 2, the positive terminal 4 and the negative terminal 5 are provided on the same side.

  In the assembled battery 1 shown in FIG. 1, eight batteries 2 shown in FIG. 2 are arranged radially. The batteries 2 are arranged radially such that the positive electrode terminal 4 and the negative electrode terminal 5 are located inside, and a wedge-shaped spacer 3 is arranged between the batteries 2. The wedge-shaped spacer 3 is arranged so that its tip 3a is located inside.

  The spacer 3 has an inclined surface 3 b that contacts the side surface of the battery 2. The length from the inner end 3a to the outer end of the inclined surface 3a is 130 mm, and the angle of the tip 3a formed by the two inclined surfaces 3b is 45 °. The height of the spacer 3 (the height in the direction perpendicular to the drawing in FIG. 1) is 105 mm. Such spacers 3 are respectively provided between the eight batteries 2, and eight spacers 3 are used in the assembled battery 1 as a whole.

  FIG. 3 is a perspective view showing an arrangement state of the spacer 3. As shown in FIG. 3, spacers 3 are respectively arranged between the batteries 2 arranged radially. In FIG. 3, the battery 2 is indicated by a dotted line. Further, only the straight line portion of the positive electrode terminal and the negative electrode terminal of the battery 2 is shown by a dotted line.

  As shown in FIG. 3, a pedestal 9 for placing the battery 2 is provided below the space in which the battery 2 is placed. The pedestal 9 may be attached below the inclined surface of the spacer 3. The side surface of the battery 2 to be pressed has a lateral length (a length along the direction from the inside to the outside of the assembled battery) of 110 mm and a length of 100 mm. Therefore, the inclined surface, which is the pressure surface of the spacer 3, has a flat portion wider than the side surface of the battery 2 to be pressed. For this reason, the side surface of the battery 2 can be uniformly pressurized.

  Referring to FIG. 1, the positive terminal 4 of the battery 2 is directly connected to the negative terminal 5 of the adjacent battery 2 in the central space of the assembled battery 1. In the adjacent battery 2, the negative electrode terminal 5 is provided at the location of the positive electrode terminal 4 of the battery 2 shown in FIG. 2, and the positive electrode terminal 4 is provided at the location of the negative electrode terminal 5. Therefore, in the adjacent battery 2, the positive electrode terminal 4 and the negative electrode terminal 5 are attached so that the position of an up-down direction may be reversed. For this reason, as shown in FIG. 1, the bent portion 4b of the positive electrode terminal 4 and the bent portion 5b of the negative electrode terminal 5 of the adjacent battery 2 can be overlapped with each other in the holes 4c and 5c formed respectively. The connecting member 8 composed of a bolt and a nut can be tightened and fixed.

  Similarly, on the back side of the drawing not shown in FIG. 1, the negative electrode terminal 5 and the positive electrode terminal 4 of the battery 2 adjacent to the opposite side are connected. Thus, the eight batteries 2 are electrically connected in series by connecting the positive electrode terminal 4 and the negative electrode terminal 5 respectively between adjacent terminals. In this way, eight batteries 2 are connected in series, and the positive terminal 6 and the negative terminal 7 shown in FIG. 1 are used as terminals connected to the outside.

  In this example, as shown in FIG. 1, the positive electrode terminal and the negative electrode terminal are arranged in the central space inside the assembled battery, and the terminals are directly connected to the adjacent batteries, whereby each Batteries are electrically connected in series. For this reason, it is not necessary to use a lead wire or the like for connecting the terminals, and a plurality of batteries can be easily connected.

  In this embodiment, as shown in FIG. 1, wedge-shaped spacers 3 are arranged between the batteries 2. Therefore, the side surface of the battery 2 can be pressurized by pressing the spacer 3 inward. Since the spacers 3 are arranged between the batteries, each battery can be pressed almost uniformly by pressing each spacer 3 inward.

  In this embodiment, as shown in FIG. 1, the outer peripheral portion 3 c of the spacer 3 is located outside the outer end portion of each battery 2, and the belt 10 is wound around the outer peripheral portion 3 c of the spacer 3. For this reason, by tightening the belt 10, each spacer 3 can be pressed inward, whereby the side surface of the battery 2 can be pressed and the battery 2 can be pressurized.

  FIG. 4 is a perspective view showing the spacer 3. The spacer 3 is made of SUS (stainless steel), and in this embodiment, a block-shaped spacer 3 that is not a hollow structure is used. In this embodiment, since the spacer 3 is made of metal, the thermal conductivity of the spacer 3 can be increased, and the heat generated from each battery can be efficiently discharged to the outside.

  As shown in FIG. 4, a belt passing portion 3d for passing the belt 10 is provided near the center in the height direction of the outer peripheral portion 3c. The belt passing part 3d is also provided on the opposite side (not shown), and the belt passing part 3d is provided at two locations of the spacer 3. By passing the belt 10 through such a belt passing portion 3d, the belt 10 is attached so as to surround the outer peripheral portion of each spacer 3 as shown in FIG. 1, and the belt 10 is tightened so that each spacer 3 faces inward. The belt 10 is fixed in the pressed state. The belt 10 may be fixed by welding the end portion by ultrasonic welding or the like, or may be fixed using a separate fixing member.

  In this embodiment, a belt made of SUS (stainless steel) is used as the belt. In FIG. 1, the belt passing portion 3d is not shown. In addition, the base part 9 is also formed from SUS in this embodiment.

  As described above, the above laminated laminate type battery was used as the battery 2, and these were connected in series to produce the assembled battery shown in FIG.

(Example 2)
An assembled battery was produced in the same manner as in Example 1 except that the spacer 3 shown in FIG. The spacer 3 shown in FIG. 5 has a hollow structure in which the outer peripheral portion 3c is opened. In the vicinity of the center in the height direction, an intermediate plate 3f for reinforcement is attached. Further, a notch 3e for positioning the belt is formed in the vicinity of the center portion in the height direction of the outer peripheral portion of the inclined surface 3b. A belt is passed through the position of the notch 3e to fix the position of the belt. The spacer 3 of this embodiment is made of aluminum. Also in this embodiment, since the spacer 3 is made of metal, the thermal conductivity of the spacer 3 can be increased, and the heat generated from each battery can be efficiently discharged to the outside. Further, in this embodiment, since the outer peripheral portion 3c of the spacer 3 has a hollow structure, outside air for cooling can be introduced into the hollow structure, and heat generated from each battery can be more efficiently transferred to the outside. Can be released.

(Comparative Example 1)
An assembled battery of a comparative example shown in FIG. 6 was produced using the same laminated laminate type battery 2 as described above. FIG. 6 is a side view, and a pressurizing plate 11 (width 100 mm, height 110 mm, thickness 10 mm) formed of SUS is disposed between the batteries 2. A constraining plate 13 is provided at both ends of the stacked battery 2, and the constraining plate 13 is connected by four connecting rods 12 that are passed through holes provided at four corners, and is provided at both ends of the connecting rod. The screw member 14 is pressurized by tightening. The restraint plate 13 has a width of 120 mm, a height of 130 mm, and a thickness of 5 mm.

  Note that the pressure plate 11 and the restraint plate 13 are made of SUS.

[Evaluation of battery pressure]
In Example 1 and Example 2, in order to evaluate the state of pressure applied to each battery, pressure-sensitive paper (reacts at 0.2 MPa and discolors where the pressure is applied) between the side surface of the battery and the spacer. The pressure state in the assembled battery was evaluated. In Comparative Example 1, the pressure sensitive paper was inserted between the battery and the pressure plate or the restraint plate, and the pressure state was evaluated.

  As a result, in Comparative Example 1, a large difference was observed in the pressure applied between the battery located at the center of the assembled battery and the battery located at the end. On the other hand, in the assembled batteries of Examples 1 and 2, it was confirmed that the pressure of the identification level was applied to each battery, and it was possible to pressurize each battery evenly.

[Evaluation of heat dissipation]
(Evaluation of laminated laminated battery)
The heat dissipation of the laminated laminated battery before assembling the assembled battery was evaluated. First, the battery was charged with a constant current of 1 It (12 A), and then charged with a constant voltage of 4.2 V. Thereafter, the discharge capacity when discharged at 1 It (12 A) was 12 Ah. The discharge capacity when discharged at 10 It (120 A) was 10.8 Ah.

  Assuming the sealed state of the battery, the temperature of the battery was increased from 20 ° C. to 60 ° C. (at the end of discharge) when insulated with a 20 mm thick heat insulating material (glass wool) and discharged at 10 It.

(Evaluation of battery pack of Example 1)
The assembled battery of Example 1 was placed in a sealed space, charged with 1 It, and then measured for temperature rise when discharged at 10 It. As a result, the battery temperature rose to 20 ° C. to 50 ° C. (immediately after discharge). Moreover, the variation of the temperature of each battery which comprises an assembled battery was less than 5 degreeC.

(Evaluation of battery pack of Example 2)
The assembled battery of Example 2 was placed in a sealed space, charged with 1 It, and then measured for temperature rise when discharged at 10 It. As a result, the battery temperature rose to 20 ° C. to 40 ° C. (immediately after discharge). Moreover, the variation of the temperature of each battery which comprises an assembled battery was less than 5 degreeC.
As described above, in the assembled batteries of Example 1 and Example 2, the temperature rise is smaller than in the case of the heat insulation state of the battery alone, and the abnormal temperature is 70 ° C. even if the assembled battery is installed in a sealed space. Never went up. Therefore, it can be seen that heat can be efficiently radiated from each battery by arranging the spacer between the batteries according to the present invention.

  The spacer in the present invention is not limited to the shape and material of the spacer in the above embodiment, and may have any inclined surface that can press the side surface of each battery by pressing the spacer inward. Good.

  Moreover, in the said Example, in the space of the center part of an assembled battery, although terminals are directly connected and each battery is connected in series, this invention is not limited to this, Each battery is connected. You may connect in parallel. Moreover, it is not limited to connecting terminals directly, You may connect between terminals using a lead wire.

  Moreover, the number of the batteries and spacers in the assembled battery of the present invention is not limited to the above-described embodiment, and may be plural. Preferably, at least 3 or more. Further, in the above embodiment, a lithium ion battery having a laminate film as an outer package is shown as an example of a square battery, but the present invention is not limited to this, and a metal can or a resin case is packaged. The battery may be a battery, or other battery such as a nickel cadmium battery or a nickel metal hydride battery.

The top view which shows the assembled battery of Example 1 according to this invention. The perspective view which shows the square battery used in the Example according to this invention. The perspective view which shows the arrangement | positioning state of the spacer in Example 1 according to this invention. The perspective view which shows the spacer used in Example 1 according to this invention. The perspective view which shows the spacer used in Example 2 according to this invention. The side view which shows the assembled battery of a comparative example.

Explanation of symbols

1 ... assembled battery 2 ... square battery
3 ... Spacer 3a ... Tip of spacer 3b ... Inclined surface (pressing surface) of spacer
3c: outer periphery of spacer 3d: belt passing portion 3e: middle plate 3f ... notch 4 ... positive electrode terminal 4a ... straight line portion of positive electrode terminal 4b ... bent portion of positive electrode terminal 4c ... hole of positive electrode terminal 5 ... negative electrode terminal 5a ... negative electrode terminal 5b ... Negative terminal bent portion 5c ... Negative terminal hole 6 ... Positive terminal 7 ... Negative terminal 8 ... Fixing member 9 ... Base 10 ... Belt 11 ... Pressure plate 12 ... Connecting rod 13 ... Restraint plate 14 ... Screw member

Claims (8)

  A plurality of prismatic batteries in which the positive electrode terminal and the negative electrode terminal are taken out from the same side are arranged radially so that the positive electrode terminal and the negative electrode terminal are located on the inner side, and a wedge-shaped spacer is provided between the batteries at the tip. The battery pack is characterized in that each battery is provided so as to be positioned at a position, and the respective batteries are pressurized by pressing the spacers inward.   The assembled battery according to claim 1, wherein the square battery is a lithium ion battery having a laminate film as an outer package.   The outer peripheral portion of each spacer is located outside the outer end portion of each battery, and a belt is wound around the outer peripheral portion of each spacer, and the spacer is pressed inward by tightening the belt. The assembled battery according to claim 1.   4. The battery according to claim 1, wherein the batteries are connected in series or in parallel by connecting the positive electrode terminal and the negative electrode terminal at an inner portion of the battery arranged radially. The assembled battery as described in the item.   The assembled battery according to claim 4, wherein the terminals are directly connected to each other.   The assembled battery according to any one of claims 1 to 3, wherein the pressurizing surface of the spacer has a flat portion equal to or wider than the pressurizing side surface of the battery.   The assembled battery according to any one of claims 1 to 3, wherein the spacer is made of metal. The assembled battery according to claim 1, wherein the spacer has a hollow structure with an outer peripheral portion opened.

Images