JP2010244894A - Battery module using sealing type square battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery module having a high weight energy density and volume energy density with easy assembly operation. <P>SOLUTION: The battery module (B) includes a battery stack (1), a positive electrode end plate (3) and a negative electrode end plate (5), wherein the battery stack (1) is configured by laminating a plurality of square batteries (C), having a positive electrode terminal plate (13) and a negative electrode terminal plate (15) made of conductive plate materials arranged while facing each other, in the facing direction of both the terminal plates, and the positive electrode end plate and the negative electrode end plate are arranged at one end and the other end in the laminating direction (X) of the battery stack (1), respectively. The battery module is further provided with a strip-shaped binding member (7) binding the positive electrode end plate (3) and the negative electrode end plate (5). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a battery module configured by stacking a plurality of sealed rectangular batteries.

  Conventionally, a cylindrical shape has generally been adopted as the shape of a sealed battery. In a cylindrical battery, a simple structure in which a positive electrode body and a negative electrode body are wound into a cylindrical shape via a separator can be used as an electrode body, and at the same time, the pressure resistance against the internal pressure of the battery is excellent. There is an advantage.

By the way, in recent years, in consideration of energy saving and CO ₂ reduction, a rechargeable secondary battery mounted on a vehicle such as an automobile or a train has been developed. When equipped with the secondary battery in a vehicle, keep stored regenerative electric power during braking to the mounting battery, because it can be used as a power source of the vehicle, to increase the energy efficiency of the vehicle operation, the CO ₂ Emissions can be reduced.

  Due to the limited installation space, vehicle batteries require a higher voltage and higher energy capacity than those used in conventional portable devices. It is common to use a battery module. When using a large battery, from the viewpoint of battery performance and productivity, an electrode body in which positive and negative electrode bodies are alternately laminated is more suitable than a wound electrode body used in a cylindrical battery. Therefore, it is desirable to use a square battery rather than a cylindrical battery (Patent Document 1).

  Thus, as a battery module structure in which a plurality of rectangular batteries are combined, for example, a casing formed by interposing a rectangular frame member made of an insulating material between the terminal plates of the positive and negative electrodes arranged opposite to each other. There has been proposed a battery in which unit cells are stacked so that one positive electrode terminal plate and the other negative electrode terminal plate of adjacent unit cells are in contact with each other (Patent Document 2). In the battery module having such a structure, a plurality of unit batteries are connected in series simply by stacking the unit batteries in the front-rear direction, so that the structure of the battery module is simplified and assembly work is facilitated.

JP 2001-110381 A Japanese Patent Application No. 2008-103901

  However, the unit battery used in this battery module has insufficient hermeticity alone. Therefore, in order to not only maintain the contact between the unit cells but also ensure the sealing of the unit cells, a tightening member for tightening the unit cell stack in the stacking direction is provided. In order to maintain the sealing of multiple stacked unit cells, it is necessary to maintain a large clamping force over a long period of time, so a thick clamping member that bears the clamping force across the battery module is formed. Therefore, rigidity must be ensured. Furthermore, it is necessary to use many fixing members for fixing the fastening member to the battery stack. For this reason, the weight and volume of a battery module increase, As a result, the energy density of a battery module falls equivalently.

  In order to solve the above-described problems, an object of the present invention is to improve the weight energy density and volume energy density of a battery module while facilitating the assembly of a battery module in which a plurality of rectangular batteries are stacked.

  In order to achieve the above-described object, a battery module according to the present invention includes a sealed prismatic battery having a positive electrode terminal plate and a negative electrode terminal plate made of conductive plate materials arranged opposite to each other, and having both terminal plates. A battery stack formed by laminating a plurality in the opposing direction, a positive end plate and a negative end plate disposed at one end and the other end in the stacking direction of the battery stack, the battery stack, and the positive end And a strip-shaped binding member for binding the negative electrode end plate. As the prismatic battery constituting the battery stack, for example, a nickel-hydrogen secondary battery can be used.

  According to this configuration, by using a unit cell including a positive electrode terminal plate and a negative electrode terminal plate arranged to face each other, a plurality of unit cells can be connected in series only by being stacked in a certain direction. The structure becomes simple. In addition, the battery stack in which the unit cells are stacked and the positive and negative electrode end plates serving as the terminals of the battery module are bound by a band-shaped binding member, and the contact between the batteries is maintained only by the binding force of the binding member. Therefore, it is possible to reduce the weight and size of the battery module by omitting the fastening member that firmly tightens the entire battery module and the fixing member that fixes the battery module to the battery stack.

  The battery module which concerns on this invention WHEREIN: The said strip | belt-shaped binding member may be formed as a binding member which has the elasticity which can be expanded-contracted in the lamination direction of the said battery laminated body. By comprising in this way, it becomes possible to ensure more favorable contact between unit cells over a long period of time, the electrical resistance of a battery module is reduced, and battery performance improves.

  In the battery module according to the present invention, an elastic body that is positioned between the binding member and the battery stack in the stacking direction in a contracted state in the stacking direction and maintains contact between the rectangular batteries. You may have. Even with such a configuration, it is possible to ensure better contact between the unit batteries over a long period of time, and the electric resistance of the battery module is reduced to improve battery performance. In particular, since the elastic body in this case does not require a function as a binding member, the degree of freedom in setting the material and structure of the elastic body is increased, and a more appropriate binding force can be set.

  In the battery module including the elastic body as described above, the elastic body may be interposed between the binding member and at least one of the positive electrode end plate and the negative electrode end plate. By comprising in this way, the contact of unit cells can be effectively ensured with a simple structure.

  The battery module including the elastic body as described above may further include an elastic body fixing plate interposed between the binding member and the elastic body. By comprising in this way, it becomes possible to hold | maintain more stably than the case where an elastic body is directly clamp | tightened with a binding member. In addition, by adjusting the dimensions of the elastic body fixing plate, the degree of freedom for setting the number and position of the elastic bodies is increased, and the elastic bodies can be held more appropriately.

  In the battery module according to the present invention, the elastic body is in contact with an end surface of the battery stack between the battery stack and the end plate on the side where the elastic body is provided, and the battery stack. It is preferable that a compression support plate is provided that transmits the elastic force of the battery to the battery stack. With this configuration, the elastic force of the elastic body is distributed and transmitted to the unit battery located at the end of the battery stack in a plane direction perpendicular to the stacking direction of the unit battery. It is possible to effectively prevent a mechanical failure from occurring in the unit battery positioned, and to improve the life of the battery module.

  As described above, when the compression support plate is provided, it is preferable that a through hole extending perpendicularly to the stacking direction is formed in the compression support plate. According to this configuration, the surface of the unit cell located at the end of the battery stack can be cooled by allowing the cooling air to pass through the through hole provided in the compression support plate. Discharge performance is improved.

  Moreover, the battery module which concerns on this invention WHEREIN: It is preferable that the heat radiating member which forms the cooling path penetrated in the direction orthogonal to the said lamination direction is interposing between the said unit cells of the said battery laminated body. By comprising in this way, since not only the unit battery located in the edge part of a battery laminated body but each unit battery which comprises a battery laminated body can be cooled effectively, the charge / discharge performance of a battery laminated body Will improve.

  In the battery module according to the present invention, a binding recess for receiving the binding member may be provided in at least one of the positive electrode end plate, the negative electrode end plate, the battery laminate, the elastic body fixing plate, and the compression support plate. . With this configuration, even when the battery module is used in an installation environment with a lot of vibration such as a vehicle, the binding member can be prevented from being displaced and dropped, so that the reliability of the battery module is improved. improves.

  In the battery module according to the present invention, a compression recess for receiving the elastic body is formed in at least one of the plate members in contact with the elastic body. With this configuration, even when the battery module is used in an installation environment with a lot of vibration such as a vehicle, it is possible to prevent the displacement and dropout of the elastic body. improves.

  As described above, when the compression recess is provided in the battery module according to the present invention, the elastic body fixing plate is provided with a through-hole penetrating in the stacking direction, and the screw portion of the through-hole has an outer side of the battery module. The compression recess is formed by a tip surface of a screw body that is screwed together to close a part of the through hole and an inner peripheral surface of the other part of the through hole, and one end portion of the elastic body is connected to the screw You may press-contact with the front end surface of a body. By configuring in this way, it is possible to easily adjust the compression force without disassembling the battery module by adjusting the screwing position of the screw body during the battery module assembly process or during use. Work becomes easy.

  As described above, when the screw body is screwed into the end plate, the screw body may be a screw body including only a shaft portion having no head. Thus, a battery module can be comprised compactly by using the screw body which does not have a head.

  In the battery module according to the present invention, the binding member may be formed of an insulating material. According to this configuration, since it is not necessary to provide an insulating member between the positive electrode end plate and the negative electrode end plate and the binding member, the battery module can be configured more compactly.

  As described above, according to the battery module of the present invention, the battery having a structure that facilitates the assembly of the battery module is used, and the fastening member that firmly tightens the entire battery module or the battery member is fixed to the fastening member. By omitting the fixing member, it is possible to facilitate the assembling work and reduce the weight and size of the battery module.

It is a perspective view which shows the battery module which concerns on 1st Embodiment of this invention. It is a perspective view which shows the unit battery used for the battery module of FIG. It is sectional drawing which shows the internal structure of the unit battery of FIG. It is a figure which shows the structure of the battery module of FIG. 1, (a) is a front view, (b) is a side view. It is the schematic which shows the example of the structure of the binding member used for the battery module of FIG. It is a side view which shows the structure of the battery module which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure of the battery module which concerns on 3rd Embodiment of this invention, (a) is a front view, (b) is a side view. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7 (a), showing a main part of the battery module in FIG. 7. It is the schematic which shows an example of the screw body used for the battery module of FIG. It is a figure which shows the structure of the battery module which concerns on 4th Embodiment of this invention, (a) is a front view, (b) is a side view. It is a perspective view which shows the heat sink used for the battery module which concerns on this invention. It is a top view which shows the modification of the heat radiating member used for the battery module which concerns on this invention. It is a perspective view which shows the cooling structure of the housing used for the battery module which concerns on this invention.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments.

  FIG. 1 is a perspective view showing a battery module B according to the first embodiment of the present invention. This battery module B is configured by using a plurality of unit batteries C which are sealed prismatic batteries, and serves as a battery stack 1 in which a plurality of unit batteries C are stacked, and terminals of the battery module B as a whole. A positive electrode end plate 3 and a negative electrode end plate 5 and a band-like binding member 7 are provided as main components. The unit battery C is configured as a nickel-hydrogen secondary battery using nickel hydroxide as a main positive electrode active material, a hydrogen storage alloy as a main negative electrode active material, and an alkaline aqueous solution as an electrolyte. In the following description, the positive electrode side in the stacking direction X of the unit cells C is referred to as the front side, and the negative electrode side is referred to as the rear side.

  The unit battery C used in the present embodiment has any structure as long as it is a sealed rectangular battery having a positive electrode terminal plate and a negative electrode terminal plate made of conductive plate materials arranged to face each other. For example, the structure shown in the perspective view of FIG. 2 can be used. This unit cell C is a square formed by a positive electrode terminal plate 13 and a negative electrode terminal plate 15 which are arranged to face each other in parallel, and a rectangular frame member 17 made of an insulating material fixed to both terminal plates 13 and 15. The casing 19 is provided. The casing 19 is formed by insert-molding both terminal plates 13 and 15 into the frame-shaped member 17, and the frame-shaped member 17 forms an outer peripheral portion 19 a of the casing 19.

  FIG. 3 is a cross-sectional view showing the internal structure of the unit cell C of FIG. Inside the casing 19, an electrode body 27 including a separator 21, a positive electrode body 23 constituting a positive electrode, and a negative electrode body 25 constituting a negative electrode is housed together with an electrolytic solution. The electrode body 27 has a pleated structure in which flat plate-like positive electrode bodies 23 and negative electrode bodies 25 are alternately stacked via a separator 21 bent into a pleat shape. In the present embodiment, the electrode body 27 is laminated in the lateral direction Y, which is one of the opposing directions of two sets of sides of the rectangular frame-shaped member 17 facing each other.

  The outer periphery of the electrode body 27 is covered with a rectangular inner frame 29 made of an insulating material. Further, the outer edge portions 13 a and 15 a of the positive electrode terminal plate 13 and the negative electrode terminal plate 15 are formed as bent portions 33 and 35 that are bent in the facing direction X, and these bent portions 33 and 35 are connected to the frame-shaped member 17. It is interposed between the inner frame 29. The frame-shaped member 17 has an inner peripheral convex portion 17b that protrudes to the inner peripheral side at a substantially central portion in the facing direction X of the main body portion 17a. The inner peripheral convex portion 17b and the bent portions 33 and 35 are the inner frame member 29. The outer peripheral surface 29a is covered.

  The frame-shaped member 17 is formed of a resin suitable for insert molding and having resistance to an aqueous alkali solution, for example, any one of polyphenylene sulfide, polybutylene terephthalate, polyphenylene oxide, polypropylene, and polyethylene, or a mixture thereof. In the present embodiment, the positive electrode terminal plate 13 and the negative electrode terminal plate 15 are formed of steel plates plated with nickel. The outer peripheral surfaces of the bent portions 33 and 35 of both terminal plates 13 and 15 are joint surfaces 31 joined to the frame-shaped member 17, and fine irregularities are formed by performing a surface treatment such as etching. Yes. This joint surface 31 is indicated by short hatching.

  Next, the structure of the battery module B according to the present embodiment will be described in detail. As shown in the side view of FIG. 4 (b), in this battery module B, a plurality of unit cells C are opposed to both terminal plates 13, 15 indicated by broken lines through a heat radiating plate 37 made of a conductive material. The battery stack 1 is formed by being stacked on X. A plurality of unit cells C are connected in series by arranging one positive terminal plate 13 and the other negative electrode terminal plate 15 of adjacent unit cells C, C so as to face each other.

  A positive electrode end plate 3 serving as a positive electrode terminal of the battery module B is disposed at the positive electrode side end of the battery stack 1, while a negative electrode terminal of the battery module B is provided at the negative electrode side end of the battery stack 1. A negative end plate 5 is arranged.

  The dimensions of the unit cell C and the end plates 3 and 5 in the vertical direction Y perpendicular to the stacking direction X are set to be substantially the same. Similarly, the dimensions in the vertical direction Z orthogonal to the stacking direction X and the horizontal direction Y are set. Are set almost identically. Each of these elements C, 3 and 5 is bound by two band-like binding members 7 which are fastened in the stacking direction X.

  The material for forming the binding member 7 is not particularly limited as long as it has strength that can withstand the binding force over a long period of time. However, in the structure in which the binding member 7 is in contact with both the positive and negative terminal plates as in the present embodiment. Must be an insulating material. Moreover, in this embodiment, the binding member 7 is comprised as a binding member which has the elasticity which can be expanded-contracted in the lamination direction X, and the battery laminated body 1 is the stacking direction X by the contraction force of the binding member 7 in the expansion | extension state. It is tightened to.

  More specifically, the bundling member 7 may have elasticity by forming the whole with an elastic material, for example, a fiber reinforced plastic (FRP) using aramid fiber or carbon fiber, rubber, or the like. However, in this embodiment, as shown in FIG.4 (b), only the part in the lamination direction X of the binding member 7 is formed as the elastic part 7a which consists of elastic materials. The elastic portion 7a in this case may be formed of an elastic material such as FRP or rubber as described above, or may be formed of a spring member such as a coil spring as shown in FIG. May be. Further, as shown in FIG. 5B, the elastic portion 7a may be formed to have elasticity by making the same inelastic material as the other portions of the binding member 7 into a wave shape.

  The positive and negative electrode terminal surfaces 3a and 5a, the outer peripheral side surfaces 3b and 5b, and the outer peripheral portion 19a of each unit battery C, which are exposed to the outside, are bundled at positions corresponding to each other. A binding recess 43 formed as a groove extending in the stacking direction X having a width dimension slightly larger than the width dimension of the member 7 is provided. By accepting the binding member 7 in the binding recess 43, the binding member 7 can be stably bound over a long period of time without shifting or dropping out of the binding position even in a use environment with a lot of vibration such as a vehicle. .

  The binding concave portion 43 is preferably provided in all of the both end plates 3 and 5 and the casing 19, but may be provided in at least one of them. Further, the binding recess 43 is not limited to these members 3, 5, and 19, and may be provided on any member among the members bound by the binding member 7 as long as the member is in contact with the binding member 7. .

  FIG. 6 is a schematic configuration diagram showing a battery module B according to the second embodiment of the present invention. In the present embodiment, as shown in FIG. 6A, an elastic body 38 that is separate from the binding member 7 and can be expanded and contracted in the stacking direction X is used as the battery stack 1 and the binding member 7 in the stacking direction X. It is arranged in between. More specifically, an elastic body 38 is interposed between the binding member 7 and the positive electrode end plate 3. Other configurations are the same as those of the first embodiment shown in FIG.

  The elastic body 38 is interposed between the binding member 7 and the positive electrode end plate 3 in a contracted state in the stacking direction X, and the battery stack 1 is stacked via the binding member 7 by the restoring force of the elastic body 38. Tightened in the direction X, the contact between the unit cells C is maintained. Thereby, it becomes possible to ensure the contact between the unit batteries C over a long period of time, the electric resistance of the battery module B is reduced, and the battery performance is improved. In particular, since the elastic body 38 is not required to function as the bundling member 7, the degree of freedom in setting the material and structure of the elastic body 38 is increased, and a more appropriate bundling force can be set.

  The elastic body 38 may be of any material and structure as long as it can expand and contract in the stacking direction X and can be stably installed between the binding member 7 and the positive electrode end plate 3. An insulating material may be used. For example, a leaf spring, a coil spring, rubber, or the like shown in FIG. 6B can be used as the elastic body 38. Moreover, the binding member 7 needs to be an insulating material also in this embodiment.

  The elastic body 38 is not limited to be interposed between the binding member 7 and the positive electrode end plate 3, and may be interposed between the binding member 7 and the negative electrode end plate 5. You may interpose between each. Moreover, although the bundling member 7 in the present embodiment has been described as a non-elastic member, it may be formed as an elastic member as in the first embodiment.

  FIG. 7 shows a battery module B according to the third embodiment of the present invention. As in the second embodiment of FIG. 6, the battery module B includes an elastic body 38 that is separate from the bundling member 7 and can be expanded and contracted in the stacking direction X, and the battery stack 1 and the bundling member 7 in the stacking direction X. Between the two. In the present embodiment, an elastic body fixing plate 39 is further interposed between the bundling member 7 and the elastic body 38 as shown in the side view of FIG.

  In other words, an elastic body fixing plate 39 made of a plate material having substantially the same vertical and horizontal dimensions as the positive electrode end plate 3 is disposed in front of the positive electrode end plate 3. An elastic body 38 is interposed between the elastic body fixing plate 39 and the elastic body fixing plate 39. As shown in the front view of FIG. 7A, in the present embodiment, four elastic bodies 38 are arranged in the vicinity of each corner of the rectangular positive electrode end plate 3.

  As described above, the elastic body fixing plate 39 made of a plate material is interposed between the binding member 7 and the elastic body 38, so that the elastic body can be stably compared with the case where the elastic body 38 is directly clamped by the binding member 7. 38 can be held. If the elastic body fixing plate 39 made of a plate material is used, it becomes easy to provide a mechanism such as a recess for holding the elastic body 38 more stably, as will be described later. It is also possible to further dispose a heat radiating plate 37 between the positive electrode end plate 3 and the elastic body 38 so that the elastic body 38 is interposed between the elastic body fixing plate 39 and the heat radiating plate 37.

  The longitudinal dimension and the lateral dimension of the elastic body fixing plate 39 may be smaller than both dimensions of the positive electrode end plate 3, but the dimension in the width direction of the band-shaped binding member 7 (in the example of FIG. It is preferable to set larger than (dimension). Furthermore, the elastic bodies 38 may be arranged in a grid shape, or may be arranged side by side in a circular shape or a concentric shape. Moreover, the shape of the elastic body 38 can be selected as appropriate, such as a square or a circle, and the size may be appropriately changed as described above. Thus, by selecting the size and shape of the elastic body 38, the surface pressure acting on the elastic body 38 can be set to an appropriate value.

  In the present embodiment, the binding recess 43 is provided on the front surface 39a and the side surface 39b of the elastic body fixing plate 39.

  FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7, showing an essential part of the present embodiment in an enlarged manner. As shown in FIG. 8, a through hole 45 penetrating in the stacking direction X is provided at a position of the elastic body fixing plate 39 corresponding to the elastic body 38. A screw body 47 formed as a slotted set screw, in which a screw groove 45a formed on the inner peripheral surface of the through hole 45 is provided with a minus groove 47b on a top surface 47a having no head, A part of the through hole 45 is closed by screwing from the outside. In this way, the first compression recess 49 that receives the one end portion 38a of the elastic body 38 is formed by the tip end surface 47c of the screw body 47 and the inner peripheral surface of the other portion of the rear side of the through hole 45. The one end portion 38a of the elastic body 38 is in pressure contact with the tip end surface 47c of the screw body 47 that forms the bottom surface of the first compression recess 49. A second compression recess 50 that is recessed in the stacking direction X and receives the other end 38 b of the elastic body 38 is provided at a position corresponding to the elastic body 38 on the front side of the positive electrode end plate 3.

  In the present embodiment, in a state where the screw body 47 is screwed up to a position that gives the elastic body 38 a sufficient elastic force to keep the battery stack 1 in contact, the top surface 47a of the screw body 47 is an elastic body. The fixing plate 39 is set so as not to protrude forward from the end face 39a. Thereby, the increase in the dimension of the battery module B can be prevented.

  As the screw body 47, a screw member having a head may be used, but from the viewpoint of suppressing the increase in the size of the battery module B as described above, a screw member consisting only of a shaft portion having no head, so-called It is preferable to use a tube screw. As such a threaded body 47, for example, a hexagon socket set screw shown in FIG. 9 can be used in addition to the slotted set screw shown in FIG. 8.

  Only one or both of the first and second compression recesses 49 and 50 shown in FIG. 8 may be provided, but by providing the recesses 49 and 50 in this way, The elastic body 38 is prevented from being displaced or dropped out. In particular, the elastic body fixing plate 39 is provided with the first compression recess 49 formed by the through hole 45 and the tip surface 47c of the screw body 47, and the one end portion 38a of the elastic body 38 is pressed against the tip surface 47c. By adjusting the screwing position of the screw body 47 at the time of assembly or maintenance of the battery module B, the compression force can be easily adjusted without disassembling the battery module B. The screw body 47 and the elastic body 38 are preferably formed of a material having a small electric resistance.

  In this embodiment, the elastic body 38, the elastic body fixing plate 39, and the screw body 47 may be formed of a conductive material or an insulating material, but these members are formed of a conductive material. In this case, since the elastic body fixing plate 39 can be used as the positive electrode end plate 3, the positive end plate between the elastic body 38 and the battery stack 1 can be omitted.

  In this case, the elastic body 38 is not limited to the coil spring as shown in FIG. 8, and any elastic member made of a conductive material, for example, a leaf spring may be used, and an elastic material such as conductive rubber is used. May be. But it is preferable that the elastic body 38 is formed with a material with small electrical resistance.

  FIG. 10 is a schematic configuration diagram showing a battery module B according to the fourth embodiment of the present invention. In the fourth embodiment, an elastic body fixing plate 39 is interposed between the bundling member 7 and the elastic body 38 as in the third embodiment of FIG. In addition to this, as shown in FIG. 10, a through hole 39 c that penetrates in the stacking direction X is provided in the central portion of the elastic body fixing plate 39, and the positive end plate 3 extends from the positive end plate 3 in the stacking direction X. A protruding positive terminal projection 51 is provided, and the tip 51a is protruded to the front side of the elastic body fixing plate 39 through the through hole 39c.

  In the present embodiment, the positive terminal projection 51 is formed by a terminal bolt fixed in contact with the positive end plate 3 by being screwed into a bolt hole 3c provided in the central portion of the positive end plate 3, and at the tip 51a. A certain head is projected forward of the elastic body fixing plate 39 and used as the positive terminal of the battery module B. Similarly, the negative electrode end plate 5 is screwed with a negative electrode terminal protrusion 53 formed as a terminal bolt.

  In this way, the through hole 39c is formed in the central portion of the elastic body fixing plate 39, and the terminal protrusion 51 protruding in the stacking direction X is provided on the positive electrode end plate 3, thereby allowing the elastic body 38 to be interposed in the stacking direction X. Space can be used effectively, and the battery module B can be reduced in size as compared with the case where the terminals protrude from the positive electrode end plate 3 in the vertical direction Y or the horizontal direction Z.

  Further, in the third embodiment shown in FIG. 7, in order to ensure the elastic performance of the elastic body 38, there are restrictions on the setting of the material and shape of the elastic body 38, and it is difficult to ensure sufficient conductivity. There is. On the other hand, in the fourth embodiment of FIG. 10, since the terminal protrusion 51 is provided independently of the elastic body 38, the material and shape of the terminal protrusion 51 can be freely set to reduce the electric resistance of the battery module B. Can be set.

  Particularly, by forming the terminal protrusion 51 as a terminal bolt screwed to the positive electrode end plate 3 as in the present embodiment, the above-described effects can be obtained with a simple structure and an easy assembly operation. it can.

  In the present embodiment, a compression support plate 55 that is a plate-like conductive member is interposed between the positive electrode end plate 3 and the battery stack 1. By disposing the compression support plate 55 in contact with the positive electrode terminal plate 3 and the battery stack 1, the elastic force of the elastic body 38 is distributed and transmitted to the unit battery C in the plane direction perpendicular to the stacking direction X. Is done. Therefore, mechanical failure due to the application of local stress to the unit battery C is effectively prevented, and the life of the battery module B is improved. The compression support plate 55 may be omitted, and can be provided in any of the embodiments described above.

  Next, the cooling structure of the battery module B according to the present invention will be described with reference to FIG. 10 as a representative. As described above, between the unit cells C of the battery stack 1 shown in FIG. 10, the heat radiating plate 37, which is a heat radiating member made of a conductive material and having the refrigerant passage 61, is interposed. The heat radiating plate 37 is preferably formed of a material having a small electric resistance. More specifically, the heat radiating plate 37 according to the present embodiment is obtained by applying nickel plating to an aluminum material, and between one positive terminal plate 13 and the other negative terminal plate 15 of the adjacent unit cell C. It is laminated so as to intervene. The heat radiating plate 37 is provided with a plurality of through holes 37a extending in a direction orthogonal to the stacking direction X, and the inside of the through holes 37a functions as a plurality of refrigerant passages 61 for allowing cooling air to pass therethrough. .

  In addition, the dimension Dh in the vertical direction Y of the heat radiating plate 37 of the present embodiment is set to be smaller than the dimension of the unit battery C. Similarly, the dimension (not shown) in the horizontal direction Z of the heat radiating plate 37 is also set. The size is set smaller than the size of the unit battery C. That is, the heat radiating plate 37 made of a conductive member is set so as not to protrude outward of the battery stack 1 from the unit battery C having the insulating outer peripheral portion 19a. More specifically, for example, as shown in FIG. 10, the planar dimension Dh of the heat radiating plate 37 is substantially matched with the planar dimension Dt of both the terminal plates 13 and 15 of the unit battery C. In this way, the size and size of the heat radiation plate 37 is increased to the minimum size necessary for efficiently cooling the battery C and ensuring conduction between the batteries C, thereby increasing the weight and volume of the battery module B. Can be suppressed. But the dimension of the heat sink 37 may be suitably set according to the configuration of the unit battery C or the entire configuration of the battery module B. For example, the planar dimension Dh of the heat sink 37 may be substantially matched to the unit battery C. In this case, a binding recess (not shown) for receiving the binding member 7 is provided on the side surface of the heat sink 37. May be.

  In the present embodiment, the compression support plate 55 is further provided with a plurality of through holes 55b extending in a direction orthogonal to the stacking direction X, and the through holes 55b are used as the refrigerant passages 61A. Although configured to function as a heat radiating member, the heat radiating plate 37 may be interposed between the compression support plate 55 and the unit battery C without providing the through hole 55b in the compression support plate 55.

  Further, since the heat radiating plate 37 is interposed between one positive terminal plate 13 and the other negative terminal plate 15 of the adjacent unit cells C, the electric unit 37 is electrically connected to electrically connect these two unit cells C. It is necessary to have conductivity. In this respect, since aluminum has a relatively low electrical resistance and a relatively high thermal conductivity, aluminum has preferable characteristics as a material for forming the heat radiating plate 37. However, aluminum tends to oxidize and contact resistance tends to increase. Therefore, the contact resistance is reduced by plating the aluminum plate with nickel having a low contact resistance.

  The heat radiating member is not limited to the heat radiating plate 37 having the through holes 37a shown in FIG. 11, and a refrigerant passage 61 extending in a direction orthogonal to the stacking direction X is formed and conduction between the unit cells C is ensured. Any embodiment may be used as long as it can be used. For example, as in the modification shown in the plan view of FIG. 12A, a plurality of rail-like heat radiation members 37A are disposed between the unit batteries C, and the gaps formed between the heat radiation members 37A are defined as refrigerant passages. 61 may be used. Alternatively, as another modification shown in the plan view of FIG. 12B, as a heat radiating member formed integrally with the unit battery C on one of the terminal plates 13 and 15 of the unit battery C, A plurality of projecting portions 37 </ b> B extending in parallel may be provided, and a gap between these projecting portions 37 </ b> B may be used as the refrigerant passage 61.

  The battery module B includes, for example, a housing 83 made of an insulating material as shown in FIG. An inflow path 91 and an outflow path 93 for circulating the air A serving as a cooling medium are formed inside the upper portion 83a and the bottom portion 83b of the housing 83, and are respectively formed on the front end wall and the rear end wall of the upper portion 83a. An exhaust fan 95 for forced cooling is installed. The air A introduced into the inflow passage 91 from the front and rear openings of the bottom 83b by the exhaust pressure of each exhaust fan 95 passes through the outflow passage 93 of the upper portion 83a and is exhausted to the outside from the front and rear exhaust fans 95. 11 enters the refrigerant passage 61 of the heat radiating plate 37 and cools the unit battery C via the heat radiating plate 37. In this way, the refrigerant passage 61 functions as a cooling medium passage for cooling the unit battery C.

  Instead of the exhaust fan 95 of FIG. 13, an intake fan (not shown) for introducing air into the casing 9 from the outside may be provided on the front end wall and the rear end wall of the bottom 83b. Further, in the present embodiment, the heat radiating plate 37 is interposed between the unit cells C at a ratio of one, but the position and number of the heat radiating plates 37 interposed may be changed as appropriate. Further, as the refrigerant, in addition to the air A, a commonly used one such as oil may be used.

  By providing such a cooling structure in the battery module B, each of the unit batteries C can be effectively cooled by a simple structure, and thus battery performance, particularly long-term charge / discharge cycle performance is improved.

  According to battery module B concerning each above-mentioned embodiment, the following effects are acquired.

  The battery module B according to the above embodiment uses a rectangular battery unit having the positive electrode terminal plate 13 and the negative electrode terminal plate 15 that are arranged to face each other as the unit battery C. They can be connected in series simply by stacking them. Therefore, the structure of the battery module B is simple, and the assembly work becomes easy.

  In addition, the positive electrode end plate 3 and the negative electrode end plate 5 respectively disposed at one end and the other end in the stacking direction X of the battery stack 1, and the battery stack 1, the positive electrode end plate 3, and the negative electrode end plate 5 are band-shaped. They are bound by the binding member 7 to keep the unit cells C in contact with each other. That is, the battery stack 1 is fastened and fixed only by the binding member 7.

  Accordingly, the battery module B can be configured to be lightweight and compact without using a thick-walled fastening member that fastens the entire battery module B and a large number of fixing members that fix the battery module B to the battery stack. The weight energy density and volume energy density of module B are improved.

  In the description of each of the above embodiments, the elastic body 38 is provided only on the positive electrode end plate 3 side. However, the elastic body 38 may be provided only on the negative electrode end plate 5 side, or You may provide in the both end plates 3 and 5 side, respectively.

  Further, since the compression support plate 55 is disposed between the unit battery C located at the end of the battery stack 1 on the side where the elastic body 38 is provided and the elastic body 38, the elastic body 38. Are distributed to the unit cell C in a plane direction perpendicular to the stacking direction X and transmitted. Therefore, mechanical failure due to the application of local stress to the unit battery C is effectively prevented, and the life of the battery module B is improved.

  In each of the above embodiments, the example in which the binding member 7 is formed of an insulating material has been described. However, the unit battery C, the positive and negative electrode end plates 3 and 5 that are bound by the binding member 7, the elastic body 38, and the elastic body. Of the members such as the fixing plate 39, the binding member 7 may be formed of a conductive member as long as the contact portion of the member that contacts the binding member 7 is formed of an insulating material. Moreover, the number and position of the binding member 7 and the elastic body 38 are not limited to the example demonstrated above, You may set suitably.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Therefore, such a thing is also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Battery laminated body 3 Positive electrode end plate 5 Negative electrode end plate 7 Bundling member 13 Positive electrode terminal plate 15 Negative electrode terminal plate 38 Elastic body 39 Elastic body fixing plate B Battery module C Unit battery X Stacking direction (terminal plate facing direction)

Claims (14)

A battery stack in which a plurality of prismatic batteries each having a positive electrode terminal plate and a negative electrode terminal plate made of conductive plate materials arranged to face each other are stacked in the opposing direction of both terminal plates;
A positive electrode end plate and a negative electrode end plate respectively disposed at one end and the other end of the battery stack in the stacking direction;
A band-shaped binding member for binding the battery stack, the positive electrode end plate, and the negative electrode end plate;
A battery module comprising:   The battery module according to claim 1, wherein the rectangular battery constituting the battery stack is a nickel-hydrogen secondary battery.   3. The battery module according to claim 1, wherein the band-shaped binding member is formed as a binding member having elasticity that can expand and contract in a stacking direction of the battery stack.   4. The contact between the rectangular batteries according to claim 1, wherein the rectangular batteries are positioned in a contracted state in the stacking direction between the binding member and the battery stack in the stacking direction. 5. A battery module further comprising an elastic body.   The battery module according to claim 4, wherein the elastic body is interposed between the binding member and at least one of the positive electrode end plate and the negative electrode end plate.   The battery module according to claim 4, further comprising an elastic body fixing plate interposed between the binding member and the elastic body.   6. The elastic structure according to claim 5, wherein an end plate of the positive electrode end plate and the negative electrode end plate on the side where the elastic body is provided is in contact with an end surface of the battery stack, and the elasticity is reached. A battery module in which a compression support plate for transmitting the elastic force of the body to the battery stack is provided.   The battery module according to claim 7, wherein the compression support plate is formed with a through hole extending perpendicular to the stacking direction.   9. The battery module according to claim 1, wherein a heat dissipation member that forms a cooling passage penetrating in a direction orthogonal to the stacking direction is interposed between the unit cells of the battery stack. 10.   10. The binding recess for receiving the binding member is provided in at least one of the positive electrode end plate, the negative electrode end plate, the battery stack, the elastic body fixing plate, and the compression support plate according to claim 1. Battery module.   11. The battery module according to claim 1, wherein a compression recess for receiving the elastic body is formed on at least one of the plate members in contact with the elastic body.   12. The screw body according to claim 11, wherein the elastic body fixing plate is provided with a through-hole penetrating in the stacking direction, and screwed into the threaded portion of the through-hole from the outside of the battery module to block a part of the through-hole. The battery module, wherein the compression recess is formed by a tip surface and an inner peripheral surface of the other part of the through hole, and one end portion of the elastic body is in pressure contact with the tip surface of the screw body.   The battery module according to claim 12, wherein the screw body is a screw body including only a shaft portion having no head.   The battery module according to any one of claims 1 to 13, wherein the binding member is formed of an insulating material.

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