JP2010061982A - Energy storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein a plurality of energy storage devices are arranged side by side and heat is conveyed to the other energy storage device arranged adjacent each other when the specific energy storage device generates heat. <P>SOLUTION: The energy storage device 10 arranged by adjoining the other energy storage device 10 has a power generation element 13 including a positive electrode element and a negative electrode element, and a case 14 for storing the power generation element. A range of the case facing to the other energy storage device side is deformed in a direction separating from the other energy storage device in proportion to temperature rise of the case. For example, the range of the case can be deformed to be convex to the inside of the case. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power storage device configured by arranging a plurality of power storage devices side by side, and relates to a power storage device constituting the power storage module.

When a secondary battery is used as a power source for a vehicle, a battery module composed of a plurality of secondary batteries (unit cells) is mounted on the vehicle. Specifically, a plurality of secondary batteries constituting the battery module are electrically connected in series so that energy necessary for traveling of the vehicle can be output. Here, as a battery module, there is a battery module in which a plurality of secondary batteries are arranged in one direction.
Japanese Patent Laying-Open No. 2002-151025 (FIG. 1) JP 2002-124224 A

  In a configuration in which a plurality of secondary batteries are arranged side by side, for example, when a specific secondary battery generates heat due to overcharging or the like, this heat is also applied to the secondary battery arranged adjacent to the specific secondary battery. May be transmitted.

  Accordingly, an object of the present invention is to provide a power storage device that can suppress heat transfer to other power storage devices arranged adjacent to each other in a configuration in which a plurality of power storage devices are arranged side by side. There is to do.

  1st invention of this application is an electrical storage apparatus arrange | positioned adjacent to another electrical storage apparatus, Comprising: It has the electric power generation element containing a positive electrode element and a negative electrode element, and the case which accommodates an electric power generation element. And the area | region facing the other electrical storage apparatus side is deform | transformed in the direction away from another electrical storage apparatus according to the temperature rise of a case.

  Specifically, the region of the case can be deformed into a shape that protrudes toward the inside of the case in accordance with the temperature rise. The temperature at which the region is deformed can be the temperature at which gas is generated from the power generation element (predicted set temperature). Thereby, when gas is generated from the power storage device, the case of the power storage device can be deformed. And it can suppress that the temperature of another electrical storage apparatus raises to the temperature of the electrical storage apparatus which gas generate | occur | produced.

  The case can be formed of a shape memory alloy or a shape memory resin, or can be formed of a bimetal. Here, at least the region may be formed of the above-described material. For example, the entire case can be formed of the above-described material, or only the region can be formed of the above-described material.

  The second invention of the present application is a power storage module having a plurality of power storage devices arranged side by side, and at least one power storage device among the plurality of power storage devices is the power storage device according to the first invention of the present application. The plurality of power storage devices can be supported in a state of receiving forces in a direction approaching each other.

  Here, a spacer can be provided between two adjacent power storage devices. The spacer is used to form a path along which a heat exchange medium for exchanging heat with the power storage device moves. In the structure including the spacer, the case of the power storage device can be deformed in a direction away from the spacer as the temperature rises. At this time, the case has a contact portion that remains in contact with the spacer and a non-contact portion that is separated from the spacer.

  In the first and second inventions of the present application, a region facing the other power storage device side of the case of the power storage device is deformed in a direction away from the other power storage device according to the temperature rise of the case. Thus, even when the temperature of the power storage device rises, this heat can be suppressed from being transferred to another power storage device.

  Examples of the present invention will be described below.

  A battery module (storage module) that is Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a top view of the battery module, and FIG. 2 is a side view of the battery module. 1 and 2, an X axis, a Y axis, and a Z axis are axes orthogonal to each other, and the Z axis is an axis corresponding to the direction of gravity. The same applies to other drawings.

  The battery module 1 has a plurality of single cells (power storage devices) 10. The plurality of unit cells 10 are arranged side by side in the X direction, and a spacer 20 is arranged between two adjacent unit cells 10. As the unit cell 10, a secondary battery such as a lithium ion battery or a nickel metal hydride battery can be used. Moreover, an electric double layer capacitor (capacitor) can be used instead of the secondary battery.

  As shown in FIG. 3, the unit cell 10 includes a battery case 14, a power generation element 13 accommodated in the battery case 14, and an electrode terminal connected to the power generation element 13. The battery case 14 is made of a shape memory alloy as will be described later. The power generation element 13 is an element that can be charged and discharged, and a known configuration can be appropriately used. Specifically, the power generation element 13 can be configured by winding a laminate of a positive electrode element, a separator, and a negative electrode element in this order as shown in FIG. Further, the power generation element can be configured by alternately laminating a plurality of positive electrode elements and a plurality of negative electrode elements with a separator interposed therebetween. Each of the positive electrode element and the negative electrode element can be composed of a current collector plate and an active material layer formed on the surface of the current collector plate.

  As the electrode terminal, there are a positive electrode terminal 11 electrically and mechanically connected to the positive electrode element of the power generation element 13, and a negative electrode terminal 12 electrically and mechanically connected to the negative electrode element of the power generation element 13. The positive electrode terminal 11 and the negative electrode terminal 12 are provided on the upper surface of the battery case 14.

  The positive electrode terminal 11 of the unit cell 10 is electrically connected via a bus bar 21 to the negative electrode terminal 12 of another unit cell 10 arranged adjacent to the unit cell 10. Further, the negative electrode terminal 12 of the unit cell 10 is electrically connected via the bus bar 21 to the positive electrode terminal 11 of another unit cell 10 arranged adjacent to the unit cell 10. Thereby, the several cell 10 which comprises the battery module 1 is electrically connected in series. Here, among the plurality of unit cells 10, the positive terminal 11 in one unit cell 10 is a total plus terminal of the battery module 1. Further, the negative electrode terminal 12 in the other single cell 10 becomes the total minus terminal of the battery module 1.

  The unit cell 10 is formed in a square shape and has six outer surfaces. Specifically, the cell 10 has an upper surface, a lower surface, two first side surfaces, and two second side surfaces. The first side surface is a side surface that constitutes the YZ plane of the unit cell 10, and the second side surface is the side surface that constitutes the XZ plane of the unit cell 10. The first side surface of the unit cell 10 is in contact with the spacer 20.

  Here, among the plurality of single cells 10 constituting the battery module 1, for the single cells 10 positioned at both ends in the X direction, only one first side surface of the two first side surfaces contacts the spacer 20. ing. And the other 1st side is in contact with end plate 22 mentioned below.

  The spacer 20 is made of resin and has a plurality of protrusions 20a as shown in FIG. Each protrusion 20a extends in the Y direction. In addition, the plurality of protrusions 20a are arranged with a predetermined interval in the Z direction. The shape and number of the protrusions 20a can be set as appropriate. That is, it suffices if the protrusion 20a can form a space for moving a heat exchange medium, which will be described later.

  Since the spacer 20 is sandwiched between the two unit cells 10, the tip of the protrusion 20 a is in contact with the first side surface of the one unit cell 10. In addition, the surface of the spacer 20 opposite to the surface on which the protruding portion 20 a is formed is in contact with the first side surface of the other unit cell 10. Here, a space S (see FIG. 4) is formed between the first side surface of the unit cell 10 and the spacer 20 by the protrusion 20 a coming into contact with the first side surface of the unit cell 10. This space S becomes a flow path for moving a heat exchange medium (not shown).

  The unit cell 10 may generate heat due to charging / discharging. In addition, the unit cell 10 exhibits desired output characteristics within a predetermined temperature range, and the output characteristics may be deteriorated when the temperature is out of this temperature range. Therefore, it is necessary to warm or cool the unit cell 10 according to the state of the unit cell 10. Specifically, the temperature of the unit cell 10 can be adjusted by supplying a heat exchange medium (gas) such as air to the battery module 10.

  When the heat exchange medium is moved in the space S described above, the heat exchange medium is brought into contact with the unit cell 10 to exchange heat with the unit cell 10. Thereby, the temperature of the cell 10 can be adjusted.

  A pair of end plates 22 are disposed at both ends in the X direction of the battery module 1. Each end plate 22 is in contact with the unit cells 10 located at both ends in the X direction among the plurality of unit cells 10 constituting the battery module 1. A plurality of (four) restraining members 23 are fixed to the pair of end plates 22. Specifically, two restraining members 23 are fixed to the upper surface of each end plate 22, and two restraining members 23 are secured to the lower surface of each end plate 22.

  Thereby, the pair of end plates 22 are connected via the plurality of restraining members 23. The plurality of single cells 10 arranged in the X direction receive a force indicated by an arrow F in FIG. The force F is a force for sandwiching the plurality of single cells 10 by the pair of end plates 22. Each cell 10 contacts the spacer 20 by receiving the force F.

  Here, the structure for sandwiching the plurality of unit cells 10 is not limited to the structure shown in FIGS. 1 and 2. That is, any structure may be used as long as the force shown by the arrow F in FIG. For example, a pair of end plates 22 can be coupled using one constraining member 23, or the constraining member 23 can be fixed to an end surface of the end plate 22 in the Y direction.

  The battery module 1 mentioned above can comprise a battery pack by accommodating in a pack case (not shown). Here, the battery module 1 can be fixed to the pack case.

  Next, features of the battery module 1 in the present embodiment will be described with reference to FIGS. Here, FIG. 5 and FIG. 6 are side views showing a partial configuration of the battery module 1. First, the configuration of the battery case 14 in the present embodiment will be described.

  In the present embodiment, as will be described later, the battery case 14 is deformed in accordance with the temperature rise of the unit cell 10. Specifically, the battery case 14 in the present embodiment is formed of a shape memory alloy. A shape memory alloy has a property of recovering to a state before deformation when it is deformed in a low temperature phase (martensite) and then heated to a predetermined temperature (shape recovery temperature) or higher. The material of the shape memory alloy can be appropriately selected based on the temperature at which the battery case 14 is deformed. Specifically, a Ni—Ti alloy or a Cu—Zn—Al alloy can be used.

  When the unit cell 10 does not generate heat, the battery case 14 of each unit cell 10 is in contact with the spacer 20 as shown in FIGS. 1 and 2. Here, when the unit cell 10 generates heat due to overcharging or the like, the battery case 14 in the unit cell 10 is deformed as shown in FIG. Specifically, the first side surface 14 a of the battery case 14 is deformed so as to protrude toward the inside of the battery case 14. Then, as shown in FIG. 6, the first side surface 14 a of the battery case 14 (unit cell 10) is deformed in a direction away from the spacer 20. Here, FIG. 6 shows a state in which the single cell 10 located in the center among the three single cells 10 is generating heat.

  In addition, when overcharging is performed on the unit cell 10, gas is generated from the power generation element 13, and the temperature of the unit cell 10 may excessively increase. Therefore, the temperature at which the battery case 14 is deformed can be the predicted temperature (predicted set temperature) when gas is generated from the power generation element 13. Thereby, when gas is generated from the unit cell 10 (power generation element 13), the battery case 14 of the unit cell 10 can be deformed.

  In the present embodiment, as shown in FIG. 7, only the region R located at the center of the first side surface 14 a of the battery case 14 is deformed. That is, a region other than the region R (a so-called outer edge region) in the first side surface 14 a is kept in contact with the spacer 20. Thereby, the region R on the first side surface 14 a can be separated from the spacer 20. Here, since the force of the arrow F shown in FIG. 1 acts on the plurality of unit cells 10, it is difficult to separate the first side surface 14 a from the spacer 20 even if the entire first side surface 14 a is deformed. Therefore, in this embodiment, only a part (region R) of the first side surface 14a is deformed.

  In the present embodiment, when the first side surface 14a is deformed, the outer edge region is kept in contact with the spacer 20, but this is not restrictive. That is, it is only necessary that a part of the first side surface 14a is in contact with the spacer 20 when the first side surface 14a is deformed in accordance with the temperature rise. Then, the remaining portion of the first side surface 14 a may be separated from the spacer 20.

  In the present embodiment, the battery case 14 is formed so that the first side surface 14a is convex toward the inside of the battery case 14, and the first side surface of the battery case 14 is deformed into a flat shape at a low temperature phase. . Thus, until the temperature of the battery case 14 reaches a predetermined temperature (shape recovery temperature), the first side surface 14a of the battery case 14 is in contact with the spacer 20 in a flat state. Become.

  When the temperature of a specific unit cell 10 among a plurality of unit cells 10 rises excessively, the heat of the specific unit cell 10 may be transferred to another unit cell 10 through the spacer 20. . Here, since the spacer 20 is made of resin, the thermal conductivity is smaller than that of the air (air) although the thermal conductivity is smaller than that of the battery case 14 made of metal. For this reason, the spacer 20 is easier to transfer heat than the atmosphere. Further, if the spacer 20 is thinned in the X direction in order to reduce the size of the battery module 1, the heat of the specific unit cell 10 is easily transmitted to the other unit cell 10.

  Therefore, as in the present embodiment, a part of the battery case 14 is deformed and separated from the spacer 20, thereby suppressing the heat of the battery case 14 from being transmitted to the other unit cells 10 via the spacer 20. I am doing so. In other words, the heat transfer between the battery case 14 and the spacer 20 is suppressed by reducing the contact area between the battery case 14 and the spacer 20. Further, by separating a part of the battery case 14 from the spacer 20, an air layer is formed between the battery case 14 and the spacer 20. This air layer can suppress the heat of the battery case 14 from being transmitted to the spacer 20.

  In the present embodiment, the battery case 14 is formed of a shape memory alloy, but is not limited thereto. Specifically, the battery case 14 can be formed of shape memory resin, or the battery case 14 can be formed of bimetal. Bimetal is a laminate of a plurality of metal plates having different thermal expansion coefficients, and is deformed by a temperature change.

  When the battery case 14 is formed of bimetal, a metal material may be selected so that the battery case 14 is deformed similarly to the present embodiment. Specifically, the first side surface 14a of the battery case 14 can be constituted by a first metal plate that constitutes the inner wall surface and a second metal plate that constitutes the outer wall surface. And what is necessary is just to make the thermal expansion coefficient of a 1st metal plate larger than the thermal expansion coefficient of a 2nd metal plate.

  In the present embodiment, the entire battery case 14 is formed of a shape memory alloy, but is not limited thereto. That is, only the portion to be deformed in the battery case 14 can be formed of a shape memory alloy or the like. In the present embodiment, only the first side surface 14a of the battery case 14 can be formed of a shape memory alloy or the like.

  In the present embodiment, as shown in FIGS. 5 and 6, the two first side surfaces 14a of the battery case 14 are deformed, but the present invention is not limited to this. Here, of the two first side surfaces 14 a of the battery case 14, one first side surface 14 a is in contact with the protruding portion 20 a of the spacer 20, and the other first side surface 14 a is in contact with the entire surface of the spacer 20. Yes. That is, the two first side surfaces 14 a have different contact areas with the spacer 20. For this reason, it is also possible to deform only the first side surface 14 a that is more in contact with the spacer 20.

  Furthermore, in this embodiment, the case of using a rectangular unit cell has been described, but the present invention is not limited to this. Specifically, a cylindrical unit cell can also be used.

  When a battery module is constituted by using a plurality of cylindrical unit cells, each unit cell is generally supported by a pair of support plates at both ends. Specifically, openings corresponding to the number of unit cells are formed in each support plate, and the end portions of the unit cells can be supported in each opening. At this time, the plurality of unit cells are arranged side by side in the plane of the support plate, and a predetermined space exists between the unit cells arranged adjacent to each other.

  When a cylindrical unit cell is used, there is a space in advance between the unit cells arranged adjacent to each other as described above. There is no need to form. However, if at least a part of the unit cells is deformed as in the present embodiment, the distance between the unit cells arranged next to each other can be increased. In this case, a part of the cylindrical unit cell may be deformed, or the entire unit cell may be deformed. When the entire cell is deformed, the cell can be deformed so that the diameter of the cell is reduced and the length in the longitudinal direction of the cell is increased.

  As described above, if the distance between the single cells is increased, the transfer of heat between the single cells can be suppressed. Moreover, when it arrange | positions in the state which contacted the cylindrical cell, the effect similar to a present Example can be acquired. Here, when the battery case 14 is formed of resin (shape memory resin), the unit cells 10 can be brought into contact with each other without using the spacer 20, and the present invention is applied even in this case. be able to.

  On the other hand, in the present embodiment, the first side surface 14a of the battery case 14 is deformed so as to be separated from the spacer 20, but this is not restrictive. Here, the battery modules 1 shown in FIG. 1 can be arranged side by side in the Y direction. That is, it is possible to prepare a plurality of battery modules 1 and arrange these battery modules 1 side by side in the Y direction. In this configuration, the plurality of single cells 10 are arranged adjacent to each other in the Y direction.

  Therefore, the second side surface (XZ plane) of the unit cell 10, that is, the second side surface 14b of the battery case 14 shown in FIG. 7 can be deformed as in this embodiment. Thereby, the distance between the single cells 10 in the Y direction can be increased, and the transfer of heat between the single cells 10 in the Y direction can be suppressed.

  The battery module 1 of the present embodiment can be mounted on a vehicle. Such vehicles include hybrid vehicles and electric vehicles. A hybrid vehicle is a vehicle provided with other power sources such as an internal combustion engine and a fuel cell in addition to the battery module 1 as a power source. The electric vehicle is a vehicle that travels using only the output of the battery module 1. The battery module 1 of the present embodiment outputs energy used for running the vehicle by discharging, or charges kinetic energy generated during braking of the vehicle as regenerative power. It is also possible to perform charging by receiving power supply from the outside of the vehicle.

It is a top view of the battery module which is Example 1 of this invention. 3 is a side view of the battery module of Example 1. FIG. It is the schematic which shows the internal structure of a cell. It is an external appearance perspective view of a spacer. It is sectional drawing which shows the structure of the unit cell which heat | fever-generated. It is a side view which shows the structure of a part of battery module in case a specific cell produces heat. It is a figure which shows the deformation | transformation area | region in a battery case.

Explanation of symbols

1: Battery module (power storage module) 10: Single battery (power storage device)
11: Positive terminal 12: Negative terminal 13: Power generation element 14: Battery case 20: Spacer 21: Bus bar 22: End plate 23: Restraining member

Claims (10)

A power storage device arranged next to another power storage device,
A power generation element including a positive electrode element and a negative electrode element;
A case for accommodating the power generation element,
A region of the case facing the other power storage device is deformed in a direction away from the other power storage device in response to a temperature rise of the case.   2. The power storage device according to claim 1, wherein the region of the case is deformed into a convex shape toward the inside of the case in accordance with a temperature rise.   The power storage device according to claim 1, wherein the region of the case is deformed according to a temperature when gas is generated from the power generation element.   4. The power storage device according to claim 1, wherein at least the region of the case is formed of a shape memory alloy or a shape memory resin. 5.   4. The power storage device according to claim 1, wherein at least the region of the case is formed of a bimetal. 5. A power storage module having a plurality of power storage devices arranged side by side,
6. The power storage module according to claim 1, wherein at least one power storage device of the plurality of power storage devices is the power storage device according to claim 1.   7. The apparatus according to claim 6, further comprising a spacer that is disposed between two adjacent power storage devices and that forms a path along which a heat exchange medium for heat exchange with the power storage device moves. The electricity storage module described.   The power storage module according to claim 7, wherein the case of the at least one power storage device is deformed in a direction away from the spacer according to a temperature rise.   The region of the case has a contact portion that remains in contact with the spacer and a non-contact portion that is separated from the spacer when deformed in a direction away from the spacer. The power storage module according to 8. The power storage module according to any one of claims 6 to 9, wherein the plurality of power storage devices are supported in a state of receiving a force in a direction approaching each other.

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