JP2009117264A - Battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery module to make an individual battery cell temperature as uniform as possible while maintaining its radiation performance. <P>SOLUTION: A punch-plate like partitioning plate along a battery cell contour is installed inside a battery module cabinet, an internal flow passage is divided into two by arranging the partitioning plate in the nearly perpendicular direction against a lamination direction of an electrode and a separator inside the respective battery cells to function independently and respectively, and furthermore, the flow passages are formed so that cooling liquid is opposed to respective neighboring flow passage spaces pinching the partitioning plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a battery module including a plurality of battery cells.

  A conventional battery module includes a battery cell capable of performing a power supply function alone. This battery cell has a low generated voltage of about several volts and a small current capacity. Therefore, there is a battery module in a mounting form in which a plurality of battery cells are prepared and housed in a casing, and connected in a combination of series connection and parallel connection in the casing, and a required voltage value and current value are obtained.

  On the other hand, in a secondary battery module that can be repeatedly charged, heat is generated inside the battery cell at the time of discharging, so that the internal temperature of the cell rises during operation. At this time, in order to satisfy the function as a battery, it is necessary to appropriately dissipate the heat generated in the battery cell and to add a heat dissipation structure for maintaining the internal temperature of the cell below the allowable temperature.

  Furthermore, it is known that characteristics such as capacity gradually deteriorate when a battery module is used for a long time. Since the main factor governing the battery deterioration is the operating temperature, it is important to provide an excellent heat dissipation structure and heat dissipation device particularly in a large capacity battery module.

  When the battery cell in the module is significantly deteriorated, the predetermined function cannot be exhibited and the lifetime of the device is reached, but the lifetime of the entire module is dominated by the battery cell having the shortest lifetime. Moreover, the variation in the characteristics of each battery cell becomes a factor that makes battery control more complicated than necessary.

  From the above background, it is desirable that the characteristics of the plurality of battery cells in the battery module match as much as possible during use. For this purpose, it is extremely important for the heat dissipation structure of the battery module not only to keep the temperature within an allowable temperature, but also to minimize variations in individual battery temperatures.

  For example, Japanese Patent Laid-Open No. 2006-318820 is an example of a heat dissipation structure for suppressing temperature variations of a plurality of batteries. In this publication, a cooling air is formed in a reciprocating flow inside a casing that houses a battery, and a holder is provided so that the cross-sectional area of the cooling air passage decreases from the forward path to the return path. Furthermore, an example is disclosed in which the battery module is favorably cooled while suppressing temperature variations of the battery module by providing the holder with a bypass hole that connects the forward path and the return path.

JP 2006-318820 A

  In the structure disclosed in Patent Document 1, cooling air is taken in to exchange heat with the battery in order to promote heat dissipation from the battery module, but the cooling air temperature increases as it goes downstream. I can't avoid going.

  In order to reduce the influence, the downstream cross-sectional area is reduced, but this requires an increase in pressure loss, that is, an increase in the capacity of the blower that feeds cooling air. When considering a power source for driving an electric motor mounted on a vehicle, it becomes a factor that hinders reduction in size and weight.

  Furthermore, the structure that bypasses the flow from the upstream to the downstream is also difficult to reduce the temperature variation due to the rise in the air temperature, as long as the cooling air volume is constant, there is no change in the cooling air temperature at the most downstream from the viewpoint of energy balance. .

  The objective of this invention is providing the battery module which can make individual battery cell temperature uniform, maintaining heat dissipation performance.

  The object is to provide a plurality of battery cells, a housing for storing the battery cell group, an inlet portion and an outlet portion for allowing a cooling fluid for cooling the battery cell group to flow into and out of the housing, and In the battery module including a partition plate that divides the surface of the battery cell, this is achieved by arranging each battery cell in at least two different cooling spaces by the partition plate.

  This is achieved by arranging the partition plate so that the battery element inside the battery cell is divided in a direction substantially perpendicular to the stacking direction of the elements.

  The partition plate is achieved by providing a plurality of holes along the outer shape of the battery cell as many as the number of cells, and forming a plurality of cooling channels by fitting the battery cell into the hole.

  The cooling flow paths are formed adjacent to each other by the arrangement of the partition plates, and are achieved by configuring the cooling flow paths so that the flow directions of the respective cooling fluids are not collinear.

  The cooling channels are formed adjacent to each other due to the arrangement of the partition plates, and are achieved by the flow directions of the cooling fluids facing each other.

  It is a cooling channel formed adjacent to each other by the arrangement of the partition plates, and is achieved by connecting one end of the adjacent cooling channel to form a reciprocating flow.

  The battery module is achieved by being used as a power source for an electric motor mounted on a moving vehicle.

  ADVANTAGE OF THE INVENTION According to this invention, the battery module which can make individual battery cell temperature uniform can be provided, maintaining heat dissipation performance.

  Hereinafter, the configuration of the embodiment of the present invention and the operation and effect thereof will be described.

  1 to 4 illustrate a first embodiment of a battery module according to the present invention.

  FIG. 1 is a schematic perspective view of a battery module provided with this embodiment.

  FIG. 2 is a cross-sectional view from the direction A of FIG.

  In the figure, a battery module 1001 has a plurality of cylindrical battery cells 1 housed inside a housing 2. The battery cells 1 are arranged inside the housing 2 so that the cylindrical ends are located on the same plane. A punch plate-like partition plate 3 a having a plurality of circular holes along the outer shape of the battery cell 1 is attached to the inside of the housing 2. This partition plate 3 a is arranged so as to divide each battery cell 1 through the hole and divide the cell into two, and to be parallel to the end face of the battery cell 1.

  Further, a fluid inlet portion 4 and a fluid outlet portion 5 of a flow path divided by a partition plate 3a are formed on one side surface of the housing 2. The buffer 6 is provided so that the divided flow path is connected to the side facing the side. Moreover, the same partition plate 3b is provided also in the both ends of the battery cell 1, and it arrange | positions so that the end surface and side surface of the battery cell 1 may each be divided.

  The function of the partition plate 3a is to divide the cooling flow path for each cell into two. The flow paths divided into two are connected by a buffer 6. Further, by providing the fluid inlet portion 4 and the fluid outlet portion 5, a reciprocating cooling flow path is formed in the housing 2 as shown by the arrow in FIG. On the other hand, the function of the partition plate 3b is to separate the positive and negative electrode portions (not shown) provided on the end face of the generally cylindrical battery cell from the cooling channel. The cell end face is provided with wiring (not shown) for electrically connecting in series or in parallel with adjacent battery cells. The partition plate 3b prevents the electrode portion from being contaminated by fluid flowing in and out of the external connection electrode.

  FIG. 3 is a perspective view of a battery element provided with this embodiment.

  FIG. 4 is a graph showing the temperature distribution of the cooling fluid of the battery module according to this embodiment.

  In FIG. 3, the battery element 1002 is a main component housed inside the battery cell 1. The electrode is formed by laminating a sheet-like positive electrode plate 101 and a negative electrode plate 102 with two separators 103 interposed therebetween. Furthermore, the cylindrical battery element 1002 is comprised by mounting this in the shape of a winding.

  For example, in the case of a lithium ion battery, lithium manganate, lithium nickelate, lithium manganate and a composite material thereof are used as the positive electrode material, and a carbon material such as graphite is used as the negative electrode material.

  The element generates heat when the battery is charged and discharged. As is apparent from the configuration of this element, the heat dissipation of the element has a contact layer, that is, a contact thermal resistance, for each layer in the stacking direction. Therefore, thermal conductivity, that is, heat dissipation is poor.

  On the other hand, since there is no contact layer inside the cylindrical axis direction of the element, and the positive electrode and the negative electrode are made of materials having excellent thermal conductivity, there is thermal conductivity, that is, heat dissipation in this direction. Are better. Therefore, when the element generates heat, the temperature distribution (temperature gradient) inside the element is extremely large in the stacking direction and small in the cylindrical axis direction.

  In FIG. 4, the effect of this battery module is demonstrated.

  When the cooling fluid flows along the arrows shown in the figure, the fluid absorbs heat generated from the battery cells as it passes through each battery cell. For this reason, the temperature of the cooling fluid gradually increases as shown by the solid line in the graph. This tendency is the same even after the fluid turns around in the buffer section. Furthermore, since the calorific value of each battery cell is substantially constant at this time, as a result, the fluid temperature shows a V-shaped change as shown in the graph.

  Considering the temperature of each battery cell arranged along the cooling flow path with respect to such a temperature rise of the cooling fluid, the temperature of the cooling fluid passing through the cell surface differs depending on each cell as is apparent from the graph. Therefore, there is basically a difference between the upper part and the lower part of the cell, and the temperature difference also differs depending on the cell. However, when both are averaged, the fluid average temperature is substantially the same for each cell as shown by the dotted line in the graph.

  Further, when considering the temperature of each battery cell itself, as described in the description of the configuration of FIG. 3 described above, the thermal conductivity in the cylindrical axis direction of the cell is extremely good as compared with other directions. Therefore, heat transfer occurs inside the element so that the cell itself compensates for the fluid temperature imbalance of the upper and lower cooling channels. As a result, the average temperature for each battery cell is substantially the same as shown by the dashed line in the graph.

  Due to the above effects, the battery module 1001 can obtain characteristics with extremely excellent temperature uniformity.

  In the present embodiment, the description has been made assuming that the cooling fluid is air, but the configuration and the operational effects are the same even when other cooling fluids are used. Moreover, although the cylindrical shape was used as the shape of the battery cell, the shape of the battery cell is not limited as long as the arrangement relationship between the battery element and the cooling channel is maintained. For example, the same temperature uniformity can be obtained for a rectangular battery cell.

  In addition, it is desirable that the partition plate is set with a tolerance so that the battery cell is not fastened due to a difference in thermal expansion coefficient, or a soft member is set so as to be fastened.

  5 and 6 illustrate a second embodiment of a battery module according to the present invention.

  FIG. 5 is a perspective view of a battery module provided with the second embodiment.

  FIG. 6 is a cross-sectional view of the battery module viewed from the A direction and the B direction shown in FIG.

  Symbols A, B, C... Shown in the battery cells in FIG. 6 are for showing that the battery cells are the same in the A arrow view and the B arrow view.

  In the figure, the basic configuration of this embodiment is the same as that of the first embodiment. However, in particular, assuming that a large number of battery cells 1 are accommodated, a plurality of cooling fluids flowing into the housing 2 are supplied. It is configured to be divided into road paths.

  In the lower flow path of the casing, a fluid inlet partition 4 disposed on the side surface, a fluid distribution partition plate 7 provided with slits for distributing the cooling fluid to each flow path path, and the fluid distribution partition plate 7 and the casing A liquid distribution buffer 8 composed of two combinations is provided. The cooling fluid distributed to each flow path passes through the lower part of the battery cell group 1 (the lower part with the partition plate 3 as a boundary), and then passes through the rectifying partition plate 11b and the turning buffer 6, and again the rectifying partition plate 11a. It passes the upper part of a battery cell group via. The cooling fluid that has moved to the upper part (upper part with the partition plate 3 as a boundary) and passed through the battery cell group 1 is a fluid configured by the fluid assembly partition plate 9 and the combination of the fluid assembly partition plate 9 and the housing 2. After passing through the collecting buffer 10, the fluid finally exits from the fluid outlet 5.

  As described above, according to this configuration, it is possible to avoid the inlet and outlet portions of the cooling fluid from being disposed on the same side surface of the housing 2, and problems such as a shortcut of the cooling fluid are solved. Since this configuration is particularly suitable when it is necessary to store a large number of battery cells, a battery module having a higher mounting density is realized.

  In this configuration, in various partition plates, the size and shape of the slits provided in the partition plate are optimized for each pass. Alternatively, it is desirable to make the flow rate of each cooling path uniform by providing a current plate or the like inside the housing. For this purpose, the rectifying partition plate 11b and the fluid collecting partition plate 9 may be unnecessary.

  7 and 8 illustrate a third embodiment of the battery module according to the present invention.

  FIG. 7 is a perspective view of the battery module. FIG. 8 is a cross-sectional view of the battery module viewed from the A direction and the B direction in FIG.

  First, the configuration of the battery module will be described. Symbols A, B, C,... Shown in the battery cell in FIG. 8 indicate the same battery cell in the A arrow view and the B arrow view. Is for.

  In the second embodiment, the upper and lower flow paths divided by the partition plate 3 are connected to form a reciprocating flow, whereas in the third embodiment shown here, the upper and lower flow paths divided by the partition plate 3 are The inlet portions 4a and 4b and the outlet portions 5a and 5b are provided for each flow path to form two large flow paths. Further, the cooling fluid flowing through the upper and lower flow paths as viewed from each battery cell 1 is configured to be a counter flow.

  With this configuration, it is possible to avoid the cooling fluid inlet portions 4a and 4b and the outlet portions 5a and 5b from being arranged on the same side surface of the housing 2, and the cooling flow path from the inlet to the outlet is different from that of the second embodiment. Therefore, the pressure loss of the fluid is also reduced. As a result, since a smaller fluid drive source can be employed, a small and light battery module with a high mounting density is realized.

  As in the second embodiment, in various partition plates, the size and shape of the slits provided in the partition plates are optimized for each pass. Alternatively, it is desirable to make the flow rate of each cooling path uniform by providing a current plate or the like inside the housing. For this purpose, some partition plates may be unnecessary. In this embodiment, the plurality of inlets and outlets for the cooling fluid are arranged so that the inlet and the outlet do not come together on the same side, but the inlet and the outlet are arranged on the same side according to mounting restrictions. Also good.

  In the above-described embodiments, the cooling channel has been described as being divided into two upper and lower parts by the partition plate 3, but the number of divisions is not limited to two, and depending on the configuration of the battery module, a plurality of cooling channels may be provided. By inserting the partition plate 3 between the battery cells 1, a battery module with less temperature variation can be provided.

  FIG. 9 is a view for explaining a battery module provided with a fourth embodiment of the battery module according to the present invention.

  In FIG. 9, in this embodiment, electrodes of five battery cells are arranged on the same axis of the battery element and connected to form a unit, and a plurality of unit units are arranged vertically and horizontally. . Here, the flow path heights of the lowermost stage and the uppermost stage are formed by about half of the cell, while the flow path in the intermediate part forms the cell at substantially the same height. The flow of the cooling fluid is made to flow in the opposite direction above and below the cell as in the third embodiment.

  With this configuration, when the configuration of the battery module shown in Example 3 is enlarged, the pressure loss of the cooling fluid is reduced by ensuring a large flow path height in the intermediate portion, and the example The same effect as 3 is obtained. That is, such a configuration is particularly effective when the number of cells stored in the battery module is large.

  FIG. 10 is a diagram for explaining a battery module including the fifth embodiment.

  10, this figure shows a railway vehicle body 1000 on which two battery modules shown in FIG. 9 are mounted. The railway vehicle body 1000 is a vehicle that plays a role of supplying power to a drive motor as a hybrid drive system including a power generation engine, a generator, a power converter, and a battery module 1001, for example. FIG. Here, a power generation engine, a generator, a power converter, and the like are not shown.

  In this embodiment, in the embodiment shown in FIG. 9, two air-cooled battery modules 1001 using air as a cooling fluid are installed on the locomotive. Each intake port 1003 is arranged on the side surface of the vehicle, and an exhaust port of the module is arranged in the center. In this embodiment, the air exhausted here is exhausted from an exhaust port 1005 on the upper surface by a blower 1004 installed in the center. By adopting such a configuration, it is possible to prevent the warm exhaust gas that has absorbed the heat generated by the battery during traveling of the vehicle from being short-circuited to the intake port on the side surface.

  In this embodiment, a structure in which air is sucked from the side and exhausted to the upper surface is shown. However, it is important not to arrange the air supply / exhaust port on the same side. For example, depending on the size of the battery module, air is sucked from the side. A similar effect can be obtained by adopting a structure in which the air is exhausted from the other side surface.

  As described above, the battery module of the present invention forms a flow path in which a fluid is opposed to a battery cell that functions independently by inserting a partition plate that is substantially perpendicular to the stacking direction of the battery elements. As a result, a structure in which the battery cell can be actively used as a heat conducting means is realized, and variations in the temperature of the plurality of battery cells can be suppressed.

  That is, although the temperature of each fluid passing through the plurality of cooling channels is different for each battery cell, the average temperature is basically the same regardless of which battery cell is noticed. Furthermore, since the positive and negative electrodes of the element in the battery cell with high thermal conductivity straddle between the flow paths, the heat generated in the battery cell can be easily moved to the flow path that is more easily radiated. Become. By the above effect | action, in this battery module, while suppressing the cell internal temperature distribution of each battery cell in a module, the temperature variation between cells is suppressed.

It is a perspective view of the battery module provided with 1st Embodiment. It is sectional drawing seen from the A direction of FIG. It is a disassembled perspective view which shows the structure of an electrode stack. It is a figure which shows the temperature distribution of the cooling fluid in 1st Embodiment, the average temperature of the cooling fluid which flows through the battery cell surface, etc. It is a perspective view of the battery module provided with 2nd Embodiment. It is sectional drawing seen from the A direction and B direction of FIG. It is a perspective view of the battery module provided with 3rd Embodiment. It is sectional drawing seen from the A direction and B direction shown in FIG. It is a perspective view of the battery module provided with 4th Embodiment. It is sectional drawing of the rail vehicle provided with 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery cell 2 Housing | casing 3 Partition plate 4 Fluid inlet part 5 Fluid outlet part 6 Buffer 7 Fluid distribution partition plate 8 Fluid distribution buffer 9 Fluid assembly partition plate 10 Fluid assembly buffer 11 Rectification partition plate 101 Positive electrode plate 102 Negative electrode plate 103 Separator 1000 Rail vehicle body 1001 Battery module 1002 Battery element 1003 Intake port 1004 Blower 1005 Exhaust port

Claims (7)

A plurality of battery cells, a housing for housing the battery cell group, an inlet and an outlet for allowing a cooling fluid for cooling the battery cell group to flow into and out of the housing, and a surface of each battery cell. In a battery module provided with a partition plate to be divided,
Each battery cell is arrange | positioned in at least 2 or more different cooling space by the said partition plate, The battery module characterized by the above-mentioned. The battery module according to claim 1, wherein
A battery module, wherein the partition plate is arranged so that battery elements inside the battery cell are divided in a direction substantially perpendicular to the stacking direction of the elements. The battery module according to claim 2, wherein
The partition plate is provided with a number of holes along the outer shape of the battery cell, and a plurality of cooling flow paths are formed by fitting the battery cell into the hole. The battery module according to claim 3, wherein
A battery module comprising cooling channels formed adjacent to each other due to the arrangement of the partition plates, wherein the cooling channels are configured so that the flow directions of the cooling fluids are not on the same line. The battery module according to claim 4, wherein
A battery module comprising cooling channels formed adjacent to each other by the arrangement of the partition plates, wherein the flow directions of the cooling fluids face each other. The battery module according to claim 3, wherein
A battery module formed by adjoining each other by the arrangement of the partition plates, wherein one end of the adjacent cooling channels is connected to form a reciprocating flow. In the battery module according to claim 4 or 6,
The battery module is used as a power source of an electric motor mounted on a moving vehicle.

Images