JP2012119136A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery module with a long life by dissolving ununiformity of a temperature difference of unit cells in a battery holder with a simple structure.SOLUTION: The module comprises a battery holder 300, which has a plurality of battery housing parts 200, in which unit cells 100 are housed with their polarities aligned in the same direction; and in which the plural battery housing parts 200 are arranged in three or more lines. An area of the battery holder 300 has outer areas S1, S3 having the battery housing parts 100 arranged in the outside line, and a central area S2 having the battery housing parts 100 arranged in the center line. A thermal capacity per cell housing part obtained by diving a thermal capacity of the battery holder in the central area S2 by the number of the battery housing parts 100 arranged in the area is larger than that in the outer areas S1, S3.

Description

  The present invention relates to a battery module that eliminates non-uniformity in temperature difference during charging / discharging of a plurality of unit cells housed in a battery holder.

  A battery module incorporating a large number of unit cells used in a hybrid vehicle or the like may shorten the life of the battery module by rapidly degrading a specific unit cell if the temperature difference during charging and discharging is large. Therefore, it is necessary to cool each unit cell efficiently and uniformly to eliminate the non-uniformity in temperature difference during charging and discharging.

  In Patent Document 1 and Patent Document 2, in order to efficiently and uniformly cool a plurality of cells stored in the battery holder, the material of the battery holder is aluminum, and the shape is formed on the surface of the cell. A battery module to be along is described.

  However, in the case of a battery module in which a large number of unit cells are connected, the unit cells arranged on the outside that can come into contact with the cooling medium are efficiently cooled because they easily exchange heat with the cooling medium. Since the unit cell is difficult to exchange heat with the cooling medium, the cooling efficiency is deteriorated, so that the temperature difference between the unit cells may be non-uniform.

  In Patent Document 3, a plurality of battery modules in which a plurality of unit cells are linearly connected are arranged in a plurality of rows and two stages with a separator interposed therebetween and housed in an exterior case, and the exterior case is made of metal and facing the surface. In contact with the surface of the battery module as a curved shape along the surface of the battery module, and further, a circuit board is disposed on one side of the separator, and the circuit board includes a main lead plate for connecting both ends of the battery module, and a plurality of A battery module is described in which each unit cell is connected by a sub lead plate connecting the connection portions of the unit cells, and the electrodes of all the unit cells are connected to a circuit board by the main lead plate and the sub lead plate.

JP 2001-307784 A JP 2002-216726 A JP 2010-225338 A

  However, in the battery module having the above-described configuration, since the outer case cannot be configured to eliminate the temperature difference between the unit cells, the temperature difference between each unit cell due to the heat conduction of the lead plate connected to the unit cell. Therefore, the configuration is complicated.

  The present invention has been made in view of such problems, and has a simple structure that eliminates uneven temperature differences during charging / discharging of a plurality of unit cells stored in a battery holder, and has a long service life. An object is to provide a simple battery module.

  The battery module according to the present invention includes a plurality of battery storage portions in which unit cells are stored, and further includes a battery holder in which the plurality of battery storage portions are arranged in three or more rows. The area of the battery holder includes an outer area having battery storage portions arranged in an outer row, and a central area having battery storage portions arranged in a central row. The heat capacity per battery housing part obtained by dividing the heat capacity of the battery holder in the battery by the number of battery housing parts arranged in the area is larger in the central area than in the outer area.

  According to the configuration of the present invention, since the heat capacity per battery housing portion in the central region is large, the heat of the unit cells in this region is quickly conducted to the battery holder and released to the outside. Further, although the heat capacity per battery storage part in the outer region is small, since this region is adjacent to the outside, the heat of the unit cell is easily radiated from the battery holder to the outside.

  Further, the plurality of battery storage portions provided in the battery holder are arranged in a staggered manner between the tangent line connecting the outer ends of the battery storage portions in the outer region and the end portions of the battery holder. The shortest distance is shorter than the shortest distance between the tangent line connecting the outer ends of the battery storage units in the central region and the tangent line connecting the central ends of the battery storage units in the outer region. Small is preferable.

  According to this configuration, the space between the outer end portion of the battery storage portion in the outer region and the battery holder end portion is thinned, and the space between the battery storage portion in the central region and the battery storage portion in the outer region is set. In order to increase the thickness, the heat of the unit cell in the central region is quickly conducted and dissipated to the battery holder, while the heat of the unit cell in the outer region is easily radiated from the battery holder to the outside.

  Moreover, it is preferable that the distance between each battery accommodating part in the area | region of the said center side is larger than the distance between the battery accommodating parts in an outer area | region.

  According to this configuration, since the periphery of each battery housing portion can be thickened in the central region, the heat of the unit cells in each battery housing portion can be reliably conducted to the battery holder. it can.

  In addition, the number of battery storage portions in the outer region is preferably larger than the number of battery storage portions in the central region.

  According to this configuration, since the battery storage portion can be provided in the vicinity of each corner portion of the battery holder, the heat capacity per battery storage portion in the outer region can be reduced.

  Further, the plurality of battery storage portions provided in the battery holder may be arranged in a grid instead of being arranged in a staggered manner.

  Even in this configuration, the space between the outer end of the battery housing portion and the battery holder end in the outer region is thinned, and the space between the battery housing portion in the central region and the battery housing portion in the outer region is thick. Since it can be made flesh, the heat of the unit cell in the central region is quickly conducted and dissipated to the battery holder, while the heat of the unit cell in the outer region is easily radiated from the battery holder to the outside.

  Moreover, it is preferable that the outer peripheral part of the said battery holder is comprised along the shape of the said battery accommodating part.

  According to this configuration, the heat capacity per battery storage portion in the outer region can be reduced, and the shape of the battery holder can be reduced, so that space saving of the battery module can be achieved.

  The battery holder is preferably formed of aluminum or an aluminum alloy.

  According to this configuration, since aluminum and aluminum alloy have high thermal conductivity, it is easy to conduct heat from the unit cells stored in the battery holder to the outside, and aluminum and aluminum alloy are lightweight. Therefore, the weight reduction of the battery module can be achieved.

  According to the present invention, in order to increase the heat capacity per battery storage unit arranged on the center side of the battery holder and reduce the heat capacity per battery storage unit arranged outside the battery holder, with a simple structure, Dissipates heat from the cells arranged in the center, which tend to be high temperature, to the outside, eliminates uneven temperature differences during charging / discharging of multiple cells in the battery holder, and has a long service life A battery module can be provided.

It is a perspective view of the battery holder in which a unit cell is accommodated. It is a figure explaining a battery module which has a battery holder in which a plurality of unit cells were stored. It is sectional drawing which showed the structure of the unit cell typically. It is a figure explaining arrangement | positioning to the housing | casing of a unit cell.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. However, the embodiments are for facilitating understanding of the principle of the present invention, and the scope of the present invention is as follows. The present invention is not limited to the embodiments, and other embodiments in which those skilled in the art appropriately replace the configurations of the following embodiments are also included in the scope of the present invention.

  FIG. 1 is a perspective view of a battery holder 300 in which the unit cell 100 is accommodated. As shown in FIG. 1, the battery module 900 according to the present embodiment includes a battery holder 300 having a plurality of battery storage units 200 in which the unit cells 100 are stored. The battery storage unit 200 is, for example, a cylindrical cavity having a circular cross section so that the cylindrical unit cell 100 can be stored.

  FIG. 2 is a diagram illustrating a battery module 900 having a battery holder 300 in which a plurality of unit cells 100 are accommodated. As shown in FIG. 2, the battery storage units 200 are arranged in, for example, a first row, a second row, and a third row. Therefore, the battery holder 300 includes, for example, a region S1 including the battery storage units 200 arranged in the first row and a region S2 including the battery storage units 200 arranged in the second row. And a region S3 including the battery storage portions 200 arranged in a third row.

  Moreover, the battery storage parts 200 are arranged in a staggered pattern. Here, the zigzag pattern means that the battery storage units 200 are arranged at equal intervals in the first column, the second column, and the third column, and the battery storage units 200 are, for example, half of each other between adjacent columns. A state that is shifted by a distance. By arranging the battery storage units 200 in a zigzag pattern, the area inside the battery holder 300 can be used effectively.

  The number of battery storage units 200 in the region S1 and the region S3 is, for example, five, and the number of battery storage units 200 in the region S2 is, for example, four. As described above, by increasing the number of the battery storage units 200 in the outer region S1 and the region S3 to be larger than the number of the battery storage units 200 in the region S2, the vicinity of each corner of the battery holder 300 can be thinned. It is possible to reduce the heat capacity per battery storage unit 200 in the regions S1 and S3.

  The battery holder 300 is formed with aluminum or an aluminum alloy, for example. The aluminum alloy is not particularly limited as long as it is lightweight and has good thermal conductivity. For example, Al-Mg alloy, Al-Mg-Si alloy, Al-Zn-Mg alloy, Al -Zn-Mg-Cu alloy or the like can be used.

  The outer peripheral part of the battery holder 300 is configured along the shape of the battery housing part 200. Therefore, in the region S2, one end side and the other end side are formed in a curved concave shape inside. . In addition, although illustration is abbreviate | omitted, it is more preferable to form an outer periphery part in the area | region S1 and area | region S3 in the smooth wave shape along the shape of each battery accommodating part 200. FIG.

  Next, the unit cell 100 stored in the battery storage unit 200 will be described. FIG. 3 is a cross-sectional view schematically showing the configuration of the unit cell 100. As the unit cell 100, for example, a cylindrical lithium ion secondary battery as shown in FIG. 3 can be adopted. This lithium ion secondary battery is provided with a safety valve mechanism that releases gas to the outside of the battery when the pressure in the battery increases due to the occurrence of an abnormality such as an internal short circuit.

  In the unit cell 100, an electrode group 104 in which a positive electrode 101 and a negative electrode 102 are wound through a separator 103 is housed in a battery case 107 together with a non-aqueous electrolyte. Insulating plates 109 and 110 are arranged above and below the electrode group 104, the positive electrode 101 is joined to the filter 112 via the positive electrode lead 105, and the negative electrode 102 is also connected to the negative electrode terminal via the negative electrode lead 106. Is joined to the bottom.

A paste containing a positive electrode active material and a negative electrode active material is applied to the surfaces of the positive electrode and the negative electrode, respectively. As the positive electrode active material, for example _{SiMn 2 O 4, SiCoO 2,} SiNiO 3 etc., may be used without particular limitation one or more of the positive electrode active material used in lithium ion batteries. As the negative electrode active material, for example, one or more negative electrode active materials used in lithium ion batteries, such as amorphous carbon and graphite carbon, can be used without particular limitation. As the non-aqueous electrolyte, for example, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and the like can be used.

  The filter 112 is connected to the inner cap 113, and the protrusion of the inner cap 113 is joined to the metal valve plate 114. Further, the valve plate 114 is connected to a terminal plate 108 that also serves as a positive electrode terminal. The terminal plate 108, the valve plate 114, the inner cap 113, and the filter 112 are integrated to seal the opening of the battery case 107 via the gasket 111.

  When an abnormality such as an internal short circuit occurs in the unit cell 100 and the pressure in the unit cell 100 increases, the valve body 114 swells toward the terminal plate 108 and the inner cap 113 and the valve body 114 are disconnected. The current path is interrupted. When the pressure in the unit cell 100 further increases, the valve body 114 is broken. As a result, the gas generated in the unit cell 100 is discharged to the outside through the through hole 112a of the filter 112, the through hole 113a of the inner cap 113, the tear of the valve body 114, and the opening 108a of the terminal plate 108. Is done.

  Next, the arrangement of the unit cells 100 housed in the battery holder 300 in the housing will be described. FIG. 4 is a diagram illustrating the arrangement of the unit cells 100 in the housing.

  As shown in FIG. 4, in the battery module 900, a plurality of unit cells 100, 100,... Are accommodated in a case. The battery holder 300 is omitted for easy viewing of the drawing. The case includes a lid 323, a housing 325, and a partition plate 327. The lid body 323 and the housing 325 sandwich the partition plate 327. In such a case, the space formed by the housing 325 and the partition plate 327 is the battery chamber 331, and the space formed by the lid 323 and the partition plate 327 discharges the gas to the outside. It is.

  In the battery chamber 331, the plurality of unit cells 100, 100,... Are accommodated in the housing 325 with the open portion 108a facing up, and are arranged in the longitudinal direction of the case. Through holes are formed in the partition plate 327 at intervals in the longitudinal direction, and the open portion 108a of the unit cell 100 is exposed from each of the through holes.

  An exhaust port portion 329 is formed in the exhaust chamber 333. Specifically, a notch is formed in one end surface of the lid body 323 in the longitudinal direction, whereby a gap exists between the lid body 323 and the housing 325 at one longitudinal end of the case. This gap is the exhaust port 329.

  Next, returning to FIG. 2, in the present embodiment, the straight line Lc connecting the upper ends of the respective battery storage units 200 in the region S <b> 2 and the lower end of the battery storage unit 200 in the region S <b> 1. The shortest distance d2 between the connecting straight lines Lb is larger than the shortest distance d1 between the straight line La connecting the upper ends of the battery storage units 200 in the region S1 and the battery holder end. Further, the distance d4 between the battery storage units 200 in the region S2 is larger than the distance d3 between the battery storage units 200 in the region S1.

  Therefore, the periphery of the battery storage unit 200 in the region S1 is formed thin, while the periphery of the battery storage unit 200 in the region S2 is formed thick, and the heat capacity per battery storage unit 200 in the region S2 is the battery in the region S1. It is set to be larger than the heat capacity per storage unit 200. Similarly, the heat capacity per battery storage unit 200 in the region S2 is larger than the heat capacity per battery storage unit 200 in the region S3.

  Thereby, the heat of the unit cell 100 in the region S2 is immediately conducted to the battery holder 300 and released to the outside, whereas the unit cell 100 in the region S1 and S3 is adjacent to the outside, so that the heat is stored in the battery holder. Heat is easily radiated from 300. Therefore, the non-uniformity of the temperature difference during charging / discharging of the plurality of unit cells 100 housed in the battery holder 300 can be eliminated, and the life of the battery module 900 can be extended.

<< Other Embodiments >>
In the above-described embodiment, the battery storage units 200 provided in the battery holder 300 are arranged in a staggered manner, but the scope of the present invention is not limited to such an embodiment, and the battery storage unit 200 is It is also possible to arrange (arrange in a grid pattern) so as to have a plurality of rows and a plurality of columns.

  In the above-described embodiment, the periphery of the battery storage unit 200 in the regions S1 and S3 is formed thin, while the periphery of the battery storage unit 200 in the region S2 is formed thick. Is not limited to such an embodiment. For example, the material in the regions S1 and S3 may be made of a material having a smaller heat capacity than the material in the region S2.

  Further, in the above-described embodiment, the unit cell 100 is provided with a safety valve mechanism that releases gas to the outside of the battery when the pressure in the battery rises due to the occurrence of an abnormality, but the scope of the present invention is as described above. However, the present invention is not limited to such an embodiment. The unit cell 100 may not be provided with a safety valve mechanism for releasing gas to the outside of the battery, and may be provided with no exhaust chamber 333 when arranged in a housing.

  Since the battery module according to the present invention has a long life, it is useful for a portable electronic device, a mobile communication device, or a power source of a vehicle.

DESCRIPTION OF SYMBOLS 100: Unit cell 101: Positive electrode 102: Negative electrode 103: Separator 104: Electrode group 105: Positive electrode lead 106: Negative electrode lead 107: Battery case 108: Terminal board 109,110: Insulation board 111: Gasket 112: Filter 113: Inner cap 114 : Valve body 200: Battery storage unit 300: Battery holder 323: Cover body 325: Housing 327: Partition plate 333: Exhaust chamber 900: Battery module

Claims (7)

In a battery module comprising a plurality of battery storage parts for storing unit cells, and further comprising a battery holder in which the plurality of battery storage parts are arranged in three or more rows,
The region of the battery holder has an outer region having battery storage portions arranged in an outer row, and a central region having battery storage portions arranged in a central row,
A battery module, wherein a heat capacity per battery housing portion obtained by dividing the heat capacity of the battery holder in each region by the number of battery housing portions arranged in the region is larger in the central region than in the outer region. The plurality of battery storage portions provided in the battery holder are arranged in a staggered manner,
The shortest distance between the tangent line connecting the outer end portions of each battery storage portion in the outer region and the battery holder end portion is the tangent line connecting the outer end portions of each battery storage portion in the central region, and 2. The battery module according to claim 1, wherein the battery module is smaller than a shortest distance between a tangent line connecting the end portions on the center side of each battery storage portion in the outer region.   3. The battery module according to claim 2, wherein a distance between the battery storage portions in the central region is larger than a distance between the battery storage portions in the outer region.   4. The battery module according to claim 2, wherein the number of battery storage portions in the outer region is larger than the number of battery storage portions in the central region.   The battery module according to claim 2, wherein the plurality of battery storage portions provided in the battery holder are arranged in a grid instead of being arranged in a staggered manner.   The battery module according to any one of claims 1 to 5, wherein an outer peripheral portion of the battery holder is configured along a shape of the battery housing portion.   The battery module according to any one of claims 1 to 6, wherein the battery holder is made of aluminum or an aluminum alloy.

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