JP2022115909A - battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack including a battery group whose thermal resistance is reduced to reduce a temperature of a single battery in the battery group.

SOLUTION: A battery pack includes a battery cell comprising a pair of wide side surfaces, a pair of narrow side surfaces, a bottom surface connecting the wide side surfaces and the narrow side surfaces, and a top surface on which an external terminal is disposed. The battery pack comprises: a first battery group obtained by stacking a plurality of battery cells so that wide side surfaces are made to face each other; a second battery group obtained by stacking a plurality of battery cells so that wide side surfaces are made to face each other; and a housing that stores the first battery group and the second battery group. Wide side surfaces forming the respective upper most and lower most parts of the first battery group and the second battery group are disposed in the housing in positional relation of the wide side surfaces not facing each other. The first battery group's surface on which an external terminal is disposed and the second battery group's surface on which an external terminal is disposed are disposed so as to face each other. A surface on the opposite side to a terminal of each of the first battery group and the second battery group is made to face an inner surface of the housing and not to face the other battery group.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to battery packs.

Against the background of environmental problems and resource depletion problems, there is a demand for the development of energy-saving products with a low environmental load for the preservation of the global environment. Eco-cars such as hybrid electric vehicles and electric vehicles are attracting attention as one of the products that will lead to the reduction of CO ₂ , and their sales are increasing. The demand for on-vehicle secondary batteries mounted in these eco-cars is also increasing. Examples of vehicle-mounted secondary batteries include lithium-ion secondary batteries, lead-acid batteries, nickel-metal hydride batteries, and the like. Among them, lithium-ion secondary batteries generally have a higher discharge potential than lead-acid batteries, nickel-metal hydride batteries, and the like.

For full-scale application, lithium-ion secondary batteries are required to have higher energy density, higher power density, longer life, and the like. In order to increase the output of the battery, it is effective not only to increase the potential but also to input/output a large current from the battery. However, when a large current is input/output from the battery, heat is generated inside the battery due to the internal resistance of the battery. If the generated heat cannot be sufficiently removed from the battery, the battery temperature will rise. Battery characteristics such as battery capacity and internal resistance of lithium ion batteries tend to deteriorate depending on the battery temperature. In particular, the higher the battery temperature, the more the battery deteriorates, often resulting in a decrease in capacity and an increase in internal resistance. Therefore, it is necessary to develop a technique for improving the heat dissipation performance of the battery.

When a plurality of lithium ion cells (hereinafter referred to as cells) are combined and used as a battery group (for example, when used as a battery module or battery pack), the temperature difference between the cells in the battery group should be reduced. Furthermore, it is desired that the maximum temperature reached by the batteries in the battery group is low. This is because when the temperature difference between the cells is large and the maximum temperature reached is high, the difference in deterioration tends to occur between the cells. Since the characteristics of a battery group tend to be rate-determined by the characteristics of the most deteriorated battery among the single cells included in the battery group, it is necessary to design a battery group in which a specific battery does not deteriorate.

Therefore, in a battery group formed by combining a plurality of single cells, various battery arrangement configurations have been developed. For example, Patent Literature 1 describes a configuration in which two battery groups each having five cells stacked in a direction substantially perpendicular to the wide surface of the cell are arranged side by side on a plate that constitutes the bottom surface of the housing. It is In general, the same current value is applied to batteries connected in series, so if the batteries have approximately the same internal resistance, the temperature of the batteries will be about the same. In this case, since it is difficult for heat flow to occur between the batteries, the more the number of stacked batteries, the closer the temperature of the central part of the stacked battery group becomes to the adiabatic state, and the higher the temperature becomes compared to the end part of the battery group. It has been known. When the battery group connected in series is divided into two rows as in Patent Document 1, the battery group has the same configuration as five batteries stacked when viewed from the bottom of the housing, so the central part of the battery group There is an advantage that the temperature of the battery is easy to drop. In addition, since the series battery group is separated, there is a feature that the height can be reduced.

U.S. Pat. No. 9,406,916

When the side surfaces of the battery groups are thermally and physically connected to each other as in the structure described in Patent Document 1, the path for heat to escape from the connecting surfaces of the battery groups is the path sandwiched between the battery groups. The heat must be dissipated through the member and the housing in front of the member. Redundant heat dissipation paths tend to increase thermal resistance, and there is room for improvement in order to improve heat dissipation.

In such a configuration, when the cooling efficiency decreases (for example, when the flow rate of forced air is small, or when the input/output current is large and the amount of heat generated by the cells is large), the battery temperature in the configured battery group In particular, among the cells stacked in the battery group, the battery temperature of the cells arranged near the center is high, and there is a possibility that the deterioration progresses. An object of the present invention is to provide a battery pack in which the temperature difference between battery groups is small.

A battery pack according to the present invention is a battery cell comprising a pair of wide side surfaces, a pair of narrow side surfaces, a bottom surface connecting the wide side surfaces and the narrow side surfaces, and a top surface on which external terminals are arranged. A first battery group in which a plurality of battery cells are stacked with the wide side surfaces of the battery cells facing each other; a second battery group in which a plurality of battery cells are stacked with the wide side surfaces of the battery cells facing each other; A housing for housing one battery group and a second battery group, a surface on which the external terminals of the first battery group are arranged, and a surface on which the external terminals of the second battery group are arranged are arranged opposite each other.

According to the present invention, the surfaces of the battery groups on which the external terminals are arranged face each other in the housing, and the structure is such that the battery groups are not thermally and physically connected to each other, thereby reducing the thermal resistance of the battery groups. It is possible to reduce the temperature of the single cells in the battery group.

A diagram for explaining an example of a specific configuration of a battery group in Examples 1 and 2. FIG. 10 is a diagram for explaining an example of a specific wiring configuration implemented when electrically connecting unit cells present in opposing battery groups in Examples 1 and 2 in series; FIG. 3 is an exploded perspective view for explaining an example of a specific configuration of a battery module implemented when the battery groups in Example 1 are arranged facing each other in a housing. FIG. 4 is a plan view of the battery module illustrated in FIG. 3 with the lid removed and the inside of the module viewed from the upper surface of the lid; FIG. 5 is an exploded plan view of a portion where the support base and electrical equipment shown in FIG. 4 are integrated; A diagram for explaining an example of a specific configuration of a battery group in Example 3. A diagram for explaining an example of a specific configuration of a battery group in Example 4. FIG. 10 is a plan view of the top surface of the battery module with the lid removed, for explaining an example of the configuration of a specific battery module when the battery groups in Example 5 are arranged facing each other in the housing. A diagram for explaining an example of a specific configuration of a battery group in Comparative Example 1. FIG. 4 is a diagram for explaining an example of a specific configuration of a battery group in Comparative Examples 2 and 3; FIG. 4 is a diagram comparing the temperature rise ratios of the battery groups in Example 1 and Comparative Examples 1 and 2; FIG. 10 is a diagram comparing the temperature rise ratios of the battery groups in Example 2 and Comparative Example 3;

A mode for carrying out the present invention will be described. However, the present embodiment is not limited to the following contents in any way, and can be arbitrarily modified within the scope of the present invention. Also, the cooling environment in the present invention is an example, and the present invention can be applied to the use of other refrigerants than air and water.

Although a lithium ion secondary battery has been exemplified as the secondary battery in the present invention, this configuration can also be applied to other types of storage batteries. Moreover, the effect can be obtained regardless of the constituent members of the lithium ion secondary battery. That is, in the present invention, an electrode made of an Al collector foil and a positive electrode material having a layered structure is used as a positive electrode, and an electrode made of a Cu collector foil and a carbon material is used as a negative electrode, but other configurations are also possible. For example, heat dissipation can be improved even when Al foil is used as the collector foil of the negative electrode. In addition, although a prismatic battery is used as the shape of the lithium ion battery in this embodiment, the effect can be obtained by using other shapes such as a laminate type, a cylindrical type, and the like.

As in the configuration of the present invention, the number of battery groups contained in the housing is such that the side surfaces of the batteries are in physical and thermal contact with the side surfaces of the housing so that heat dissipation paths from the side surfaces of the battery groups are formed. Any number may be used as long as it can be shortened, but an even number is preferable in order to ensure the stability of the battery pack. For example, when there are two battery groups as in the embodiment of the present invention, the battery groups can be arranged in physical and thermal contact with the left and right side surfaces of the housing.

In addition, the number of batteries constituting the battery group can be the same as the configuration of the present invention, and the effect of the present invention can be obtained as long as the number of batteries can be accommodated in the housing and the desired voltage and capacity can be secured. As for the heat radiation effect, the smaller the number of laminated cells in one battery group, the more effective it becomes. By using six as in the embodiment of the present invention, the battery pack can be made small and has good cooling performance.

Furthermore, the effect of the present invention can be obtained even if the number of batteries in the battery groups facing each other is not necessarily the same. For example, even when the number of batteries in one of the battery groups is one or more than the number of batteries in the other, the effects of the present invention can be obtained.

Further, the effect of the present invention can be obtained even if, for example, an insulating sheet or a member having high thermal conductivity is arranged between the cells forming the battery group, and the effect of the present invention can be obtained even if they are not arranged. Also, the effect of the present invention can be obtained by introducing three-dimensional structures such as projections and grooves of various shapes such as rail-like and dot-like shapes to the insulating sheet and the member having high thermal conductivity. When the side surface of the unit cell is covered with an insulating material, these members can be made of materials with high thermal conductivity such as aluminum, aluminum die-cast, copper, and iron. In addition, when the side surface of the unit cell is not covered with an insulating material, polypropylene, polyamide, polyetherimide, PPS, PPA, PBT, or the like, or high thermal conductive resin can be used.

In the present invention, the battery groups are arranged facing each other inside the housing so that the electrode surfaces face each other. It is preferable to dispose at least a part of the elastic member. Examples of members include the following.

It is a support base that is created by using an insulating member as at least a part of a component, and the support base includes a battery safety mechanism (such as a fuse) and a control device (such as a Battery Management System: BMS). ), relays necessary for precharging, shunt resistors, conductive wiring such as bus bars and conductors, and at least one of these electrical components. In addition, the support base may be provided with screws, threaded holes or fixtures to which these electrical components can be fixed. By integrating the above-described electrical components with the support base using these fixtures, it is possible to connect the electrical components such as the safety mechanism and the battery group via conductive wiring, and to electrically connect to the external terminals. can. As a result, it is possible to introduce an insulating member between the terminal surfaces of the battery groups, so that the battery pack can be provided with high heat radiation performance while having safety against crushing.

Further, the method and positional relationship of attaching the safety mechanism and the like to these supports are not particularly limited in the present invention. For example, these devices may be arranged or built in the upper/lower surface, side surface, or inside of an insulating support base. Also, the order of electrical arrangement of these devices is not particularly limited. Also, the size and shape of the support base may be of any size and shape as long as the insulation between the two battery groups can be ensured when the battery groups are brought close to each other due to crushing. For example, the support base may be in the form of a thin plate, or may have a complicated three-dimensional shape to accommodate each electrical component, like the support base exemplified in the present invention.

If the battery group is arranged as in the present invention, the effects of the present invention can be obtained regardless of how the cells forming the battery group are electrically connected. For example, the effect of the present invention can be obtained even if the battery groups are connected in parallel by devising wiring for the battery groups. Here, as an example, an example will be described in which the cells in the battery groups are connected in series, and the two opposing battery groups are also connected in series.

Examples of the method of connecting the battery groups in series after making the battery groups face each other include the following.
(A) A method of directly connecting battery groups using a bus bar. At this time, in consideration of workability, the busbars may be electrically connected using a method such as screws or welding using a part of the busbars or wiring extended for connection. However, the method of electrical connection is not limited to these.
(B) A method of electrically connecting the busbars to each other via the supporting base including the insulating member as a constituent member. At this time, it is preferable that the support base incorporates a conductive portion such as a bus bar or a cable, and that the conductive member is used for electrical connection.
(C) A method of directly connecting battery groups with cables.
(D) A method of electrically connecting cables to each other via a support base including an insulating member as a constituent member, as described above, and the like.

In addition to electrically connecting the unit cells in series or in parallel, it is preferable to physically bind the unit cells together using a fixing jig. When the sides of the unit cells are covered with an insulating material, materials with high thermal conductivity such as aluminum, aluminum die-cast, copper, and iron can be used as the material of the fixing jig. In addition, when the side surface of the unit cell is not covered with an insulating material, polypropylene, polyamide, polyetherimide, PPS, PPA, PBT, or the like, or high thermal conductive resin can be used. Also, the method of restraint is not limited to the present invention. For example, the effect was obtained when two battery groups were bound using one set of fixing jigs and when two sets of fixing jigs were used to bind them. Moreover, the effects of the present invention were obtained even when at least part of the fixing jig was a housing.

The method of contacting each member such as the housing with the battery group and the support base is not particularly limited. Although the shape of the housing is a rectangular parallelepiped in this embodiment, the shape is not particularly limited. Further, the effects of the present invention are not limited to the current application conditions and cooling conditions to the battery pack.

Since the support exemplified in the present invention is provided with a bus bar and conductive wires having good thermal conductivity, a cooling effect can be expected when a mechanism for releasing heat from the support is provided. For example, a cooling mechanism such as a heat pipe or a cooling pipe may be provided in a portion that is in thermal contact with the support.

Further, even if the housing is provided with a cooling mechanism such as fins, a jacket using a coolant, or piping, the effect can be obtained by adopting the structure of the present invention.

Examples of the type of housing include a resin housing and a metal housing, but are not particularly limited. Preferably, the housing is made of heat-conductive metal such as aluminum, aluminum die-cast, copper, iron, or the like.

In the example of the present invention, the external terminals protruding from the lid are arranged above the space where electrical components can be arranged, but the external terminals can also be arranged above the pressurizing binding jig. Also in this case, the effects of the present invention can be obtained by adopting the structure of the present invention. In the embodiment, a conductive wire such as a bus bar is arranged on a support base that includes an insulating member as a constituent member, and various electrical components are connected to it using screws to establish an electrical connection. A method is illustrated.

(Example 1)
Hereinafter, the present invention will be described in further detail based on examples and comparative examples.

First, the outline of the battery pack 100 according to the present invention will be described with reference to FIG. FIG. 3 is an exploded perspective view of the battery pack 100 of the present invention. A battery pack 100 according to the present invention includes two battery groups 10A and 10B, a metal housing 7 that houses the two battery groups 10A and 10B, a lid 8 that closes the opening of the housing 7, and a It is composed of a support base 4 on which electrical equipment that is not installed is arranged. Note that the support base 4 is arranged in an electrical component arrangement space 4A between the battery group 10A and the battery group 10B. The battery groups 10A and 10B are arranged so that the terminals of the cells 1 (the positive terminal 12 and the negative terminal 13) face each other, and are electrically connected to each other by wiring 6. FIG. An external terminal 9 is arranged on the lid 8 and electrically connected to the wiring 6 , and electric power is taken out from the battery pack 100 via the external terminal 9 .

Details of the battery groups 10A and 10B will be described with reference to FIG. The cell 1 is composed of a pair of wide surfaces, a pair of narrow surfaces, a bottom surface, and a top surface, and a positive electrode terminal 12 and a negative electrode terminal 13 are arranged on the top surface. Insulating spacers 11 are arranged between the cells 1, and the cells 1 are stacked so that the positive and negative terminals of the terminals are alternately arranged.

A pair of pressurizing binding jigs 3 are arranged so as to face the wide surface of the uppermost unit cell 1 and the wide surface of the lowermost unit cell 1, respectively.

A pair of pressurizing binding jigs 2 are arranged facing the narrow side surfaces of the cells 1 , and the pressurizing binding jigs 2 and 3 are fixed to each other by fixing metal fittings 5 . ing.

Next, FIG. 2 shows the connection between the wiring 6 and each unit cell 1. As shown in FIG. The wiring 6 is divided into three types: a wiring 6A connected to the external terminal 9, a wiring 6C connecting the unit cells 1, and a wiring 6B connecting the battery groups 10A and 10B. These wirings 6A, 6B, and 6C are connected to form a battery group 10A and a battery group 10B. Wiring 6B of battery group 10A and wiring 6B of battery group 10B are connected to each other.

Next, FIG. 4 shows a view from the opening side of the housing 7 with the lid 8 of FIG. 3 removed. The support base 4 arranged between the first battery group 10A and the second battery group 10B is connected to the wiring 6A, and the wiring 6A is connected to the support base terminal connected to the external terminal 9 provided on the lid 8. It is electrically connected to the portion 6A1. A BMS (substrate) 20 , a shunt resistor 21 , a fuse 22 and a relay 23 are assembled to the support base 4 . The assembling method will be described in detail with reference to FIG. An insulating member such as an insulating resin material is used for the support base.

Next, the support base 4 will be described with reference to FIG. A BMS 20 and a shunt resistor 21 are arranged on one side of the support base 4, and a fuse 22 and a relay 23 are arranged on the other side. The BMS 20 and the shunt resistor 21 are assembled integrally, and one side is connected to the wiring 6A and the other side is connected to the support base terminal portion 6A1.

Since the fuse 22 and the relay 23 arranged on the other side are large components, the other side is provided with two recesses to accommodate the fuse 22 and the relay 23 therein. By adopting such a structure, it is possible to reduce the size of the integrated assembly of the support base 4 and the electrical equipment. Note that the fuse 22 and the relay 23 may be connected to each other by the connection wiring 6A2 to be integrated, and then assembled to the support base 4. FIG. Also, when assembling the electrical components, they are assembled using parts such as screws, but the assembling method is not limited to this.

Next, the features of this embodiment will be described with reference to FIG. 3 again.

In this embodiment, the four surfaces of the battery groups 10A and 10B, that is, the two side surfaces of the battery groups 10A and 10B (surfaces on which the pressurizing binding jig 2 is arranged), the bottom surface of the cell 1, the battery group 10A, 10B is accommodated in the housing 7 so that the lowermost surface (the surface on which the lower pressurizing binding jig 3 is arranged) is in direct contact with the housing. Therefore, cooling performance is most improved when two or more battery groups 10A and 10B are accommodated. On the other hand, in order to improve the cooling efficiency, it is necessary to store the battery group 10A so that the terminal surface of the battery group 10A and the terminal surface of the battery group 10B face each other. Therefore, in the present invention, the electrical components necessary for the battery pack 100 are mounted on an insulating support base and arranged between the battery group 10A and the battery group 10B. Therefore, while improving the cooling performance of the battery pack 100, the insulation between the two battery groups 10A and 10B can be ensured, and the battery pack 100 can be prevented from increasing in size. A more detailed description will be given of how the battery pack 100 can be prevented from increasing in size. Originally, if the terminal side surface of the battery group 10A and the terminal side surface of the battery group 10B were to face each other, it would be necessary to increase the creepage distance for the two battery groups, and the volume of the battery pack 100 would increase accordingly. Therefore, the space for securing the creepage distance of the battery groups 10A and 10B can be overlapped with the space for arranging the support base, so that the battery pack 100 can be prevented from increasing in size.

As a further effect of this structure, the battery pack 100 can be configured after the electric components are once integrated with the support base 4 . Therefore, the work can be completed by collectively fixing the support base 4 to which the electrical components are fixed to the housing 7 or the like without having to arrange the electrical components in the narrow space between the battery group 10A and the battery group 10B. Workability is improved when the battery pack 100 is produced.

In this embodiment, a substrate (20) is arranged on one side of the support base 4, and a relay (23) and a fuse (22), which are large components, are arranged on the other side. With such a structure, the BMS 20, which is a planar member, can be arranged on one side, which is wasteful compared to a structure in which the relay 23 is arranged on one side of the support base 4 and the fuse 22 is arranged on the other side. The uneven space is no longer generated. Therefore, it comes to contribute to miniaturization.

In this embodiment, a bus bar is used as the wiring 6, but a cable may be used.

A current was applied to the battery pack produced as described above. At this time, a member having a low thermal conductivity was arranged on the lower surface of the housing, and a current was applied, and the test results were obtained in a constant temperature chamber with substantially no air flow. A current value was applied so that the amount of heat generated from the battery was calculated from the current value and the average was 3W. In this example, FIG. 11 shows the temperature behavior when the battery pack is in a substantially steady state after the above conditions are applied to the battery pack.

(Example 2)
In this embodiment, an electrode made of an Al collector foil and a positive electrode material having a layered structure is used as a positive electrode, and an electrode made of an Al collector foil and a spinel oxide is used as a negative electrode. A battery group was obtained by stacking six batteries as shown in FIG. 1 and fixing the periphery thereof using a fixing pressure jig. In this example, the same current application conditions and ambient cooling environment as in Example 1 were applied to the battery having the above configuration, and the results when the battery reached a substantially steady state are shown in FIG.

(Comparative example 1)
An electrode made of an Al collector foil and a positive electrode material having a layered structure is used as the positive electrode, and an electrode made of a Cu collector foil and a carbon material is used as the negative electrode. Single battery groups 10A and 10B were formed by connecting the cells 1 in series. At this time, spacers 11 similar to those in Example 1 were arranged between the cells 1 . As shown in FIG. 9, the cells 1 are arranged so that the wide surface of the cell 1 is substantially perpendicular to the bottom surface of the housing. , 33) to obtain a battery group 10C. The housing and the battery group 10C were fixed using screws. Note that FIG. 9 is a plan view of the lid surface of the housing as viewed from above. In this comparative example, as in Example 1, electrical components are arranged on the path connecting the external terminal 9 to the unit cell 1 . The electrodes of the battery group 10C and the external terminals were electrically connected by connecting the same electrical components as in Example 1 using bus bars and cables. In this comparative example, the same current application conditions and ambient cooling environment as those in Example 1 were applied to the battery having the above configuration, and the results when the battery reached a substantially steady state are shown in FIG.

(Comparative example 2)
A comparative example was obtained by simulating the battery configuration described in Patent Document 1. Specifically, an electrode composed of an Al current collecting foil and a positive electrode material having a layered structure is used as the positive electrode, and an electrode composed of a Cu current collecting foil and a carbon material is used as the negative electrode, and these electrodes are wound. was used, and a group consisting of six single cells was used as in Example 1 so that only the battery group 10D could be compared with Example 1. The battery groups 10D were arranged such that the side surfaces of the battery groups 10D were brought into physical contact with each other. The electrical components are arranged on the path connecting the electrodes of the battery group 10D from the external terminals, and the same electrical components as in Example 1 are connected from the electrode portion to the external terminals using bus bars and cables. electrically connected. Further, in order to provide a cooling environment substantially the same as that of Example 1, a housing 77 and a lid 88 were newly provided around the battery group for comparison experiments. FIG. 11 shows the results when the battery group 10D having such a configuration was given the same current application conditions and surrounding cooling environment as in Example 1, and the battery group 10D reached a substantially steady state.

(Comparative Example 3)
In this comparative example, an electrode made of an Al collector foil and a positive electrode material having a layered structure was used as the positive electrode, and an electrode made of an Al collector foil and a spinel-based oxide was used as the negative electrode. A battery group 10D was obtained by stacking six batteries as shown in FIG. 10 and fixing the periphery thereof using a fixing pressure jig. In this comparative example, the same current application conditions and surrounding cooling environment as those in Example 1 were applied to the battery having the above configuration, and the results when the battery reached a substantially steady state are shown in FIG.

As a result of applying the conditions shown in the examples and comparative examples to the battery group, when the temperature of the battery group reached a steady state, the battery temperature increased compared to the environmental temperature. In FIGS. 11 and 12, among the examples and comparative examples of the present invention, the temperature rise from the ambient temperature was the largest among the battery groups present in comparative example 1. Taking the temperature rise of the battery as 100%, the temperature rise ratios of the single cells in each example were compared.

For Comparative Example 1, cell numbers are assigned in order from the left unit cell shown in FIG. On the other hand, except for Comparative Example 1, only the six cells with different heights are described because the cells having the same positional relationship in height from the bottom surface of the stacked battery group had substantially the same temperature. On the other hand, in the examples other than Comparative Example 1, the height from the housing bottom surface increases in ascending order of the cell number in the drawing.

The results of each figure will be explained in detail below.

FIG. 11 shows the temperature rise ratio of Example 1, which is an example to which the present invention is applied, together with Comparative Examples 1 and 2. As shown in FIG. As can be seen from the figure, in Comparative Example 1, the cell No. 1, which is the central portion of the stacked batteries, was used. It can be seen that the temperatures of 6 and 7 are the highest. This cell no. In batteries near 7, the heat generated by the surrounding batteries is not radiated, so not only the temperature of the battery itself, but also the temperature of the surrounding batteries is high, and there is no temperature difference, so heat does not flow easily. This is because the battery temperature is high.

On the other hand, in Example 1 and Comparative Example 2, as shown in FIG. 11, the number of stacked battery groups decreased, so that the temperature rise ratio of six battery groups decreased to 12 stacked battery groups. It can be seen that it has decreased compared to 1. It is considered that there is this influence, and in Comparative Example 2, the temperature rise is suppressed as compared with Comparative Example 1. In addition, in Example 1, the surfaces of the battery groups on which the external terminals are arranged face each other in the housing, and the battery groups are not thermally and physically connected to each other. As a result, the thermal resistance was reduced more than in Comparative Example 2, and the temperature of the cell was also reduced compared to Comparative Example 2.

In FIG. 12, an electrode made of an Al collector foil and a positive electrode material having a layered structure is used as the positive electrode, and an electrode made of an Al collector foil and a spinel-based oxide is used as the negative electrode. A comparison is shown between the configuration of the present invention and the configuration of a known example using six batteries. The results of FIG. 12 show that the effect of the present invention is exhibited even when the battery type is changed.

(Example 3)
Next, Example 3 will be described. The third embodiment differs from the first embodiment in that a water cooling jacket 107 is provided on the side surface of the housing 7 . In addition, the same drawing number is given to the same configuration as that of the first embodiment.

FIG. 6 shows the structure of the third embodiment. In this embodiment, a water cooling jacket 107 is provided on the side surface of the housing 7 as shown in FIG. Therefore, in addition to the effects of the first embodiment, the cooling performance can be further enhanced.

(Example 4)
Next, Example 4 will be described. The fourth embodiment differs from the first embodiment in that air cooling fins 177 are provided on the sides of the housing 7 . In addition, the same drawing number is given to the same configuration as that of the first embodiment.
FIG. 7 shows the structure of Example 4. FIG. In this embodiment, air-cooling fins 177 are provided on the side surface of the housing 7 as shown in FIG. Therefore, in addition to the effects of the first embodiment, the cooling performance can be further enhanced. In addition, since this embodiment employs an air-cooling system, although the cooling performance is lower than that of the third embodiment, there is no need for a device or the like necessary for water cooling.

(Example 5)
Next, Example 5 will be described. The fifth embodiment differs from the first embodiment in that the pressurizing binding member 2 is also used as the housing 277 . In addition, the same drawing number is given to the same configuration as that of the first embodiment.

FIG. 8 shows the structure of the fifth embodiment. In this embodiment, as shown in FIG. 8, the side surface of the housing 277 is in direct contact with the battery groups 10A and 10B, and the pressurizing binding jig 3 is connected to the housing 277. .

As shown in FIG. 8, this embodiment has a structure in which the pressurizing binding member 3 is directly connected to the housing 277 . In order to increase the contact area between the pressurizing binding jig 3 and the housing 277, in this embodiment, housing side recesses 277A and 277B for accommodating the pressurizing binding jig 3 and two housing side recesses are provided. A housing side projection 277C is provided between 277A and 277B. By adopting such a structure, the side portions of the battery groups 10A and 10B are in direct contact with the housing 277 without interposing a pressurizing binding jig, thereby improving the cooling performance. Further, by arranging the pressurizing binding jigs 3 of the battery groups 10A and 10B in the housing side recesses 277A and 277B, the contact area of the pressurizing binding jigs 3 with the housing 277 is increased. Heat dissipation from the tool 3 is promoted. Furthermore, since the two pressing binding jigs 3 are also in contact with the housing side projection 277C, heat dissipation from the pressing binding jigs 3 is further promoted.

The present invention is briefly summarized above.

In the battery pack 100 of the present invention, a battery cell ( 1), and a first battery group (10A) in which a plurality of battery cells (1) are stacked with the wide side surfaces facing each other, and a plurality of battery cells (1) are stacked with the wide side surfaces facing each other. a second battery group (10B), and a housing (7) that houses the first battery group (10A) and the second battery group (10B), The surface on which the terminals (12, 13) are arranged and the surface on which the external terminals (12, 13) of the second battery group (10B) are arranged are arranged to face each other. With such a structure, four surfaces of the battery groups 10A and 10B, that is, two side surfaces of the battery groups 10A and 10B (surfaces on which the pressure binding jig 2 is arranged), and the bottom surface of the cell 1 , the lowermost surface of the battery groups 10A and 10B (the surface on which the lower pressurizing binding jig 3 is arranged) can be directly contacted with the housing 7 and used for cooling, thereby improving the cooling performance. .

In addition, the battery pack (100) according to the present invention has a surface on which the external terminals (12, 13) of the first battery group (10A) are arranged, and a surface on which the external terminals (12, 13) of the second battery group (10B) are arranged. , 13) are arranged, electric components are arranged. By adopting such a structure, the space corresponding to the creepage distance of the battery groups 10A and 10B can be used as the storage space for electrical components, and the battery pack 100 can be prevented from becoming large.

In addition, the battery pack (100) according to the present invention includes two or more parts as electrical components, provided that at least two of the board (20), the relay (23), or the fuse (22) are included. Since it can be made into one assembly, the effect of improving workability can be obtained.

Also, the battery pack (100) according to the present invention is characterized in that the electrical components are each integrated with the insulating member. By adopting such a structure, while ensuring insulation between the battery groups 10A and 10B, there is no need to arrange electrical components in the narrow space between the battery groups 10A and 10B. Therefore, the support base 4 to which the electrical components are fixed can be collectively fixed to the housing 7 or the like, so that workability can be improved while ensuring insulation between the battery groups 10A and 10B.

Also, in the battery pack (100) according to the present invention, the electrical components are the board (20), the relay (23) and the fuse (23), and the board (20) is on one side of the insulating member and the A relay (23) and a fuse (22) are arranged in . With such a structure, the BMS 20, which is a planar member, can be arranged on one side, which is wasteful compared to a structure in which the relay 23 is arranged on one side of the support base 4 and the fuse 22 is arranged on the other side. The uneven space is no longer generated. Therefore, it comes to contribute to miniaturization.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the invention described in the claims. Changes can be made. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration.

Reference Signs List 1 Single cell 2 Pressurizing binding jig 3 Pressurizing binding jig 4 Support stand 5 Fixing metal fitting 6 Wiring 7 Housing 8 Lid 9 Terminals 10A, 10B Battery group

Claims (4)

A battery pack having battery cells comprising a pair of wide side surfaces, a pair of narrow side surfaces, a bottom surface connecting the wide side surfaces and the narrow side surfaces, and a top surface on which external terminals are arranged,
A first battery group in which a plurality of battery cells are stacked with the wide side surfaces of the battery cells facing each other;
a second battery group in which a plurality of battery cells are stacked with the wide side surfaces of the battery cells facing each other;
a housing that houses the first battery group and the second battery group,
The wide side surfaces forming the uppermost portions of the first battery group and the second battery group are arranged in the housing in a positional relationship that does not face each other,
The surface on which the external terminals of the first battery group are arranged and the surface on which the external terminals of the second battery group are arranged are arranged to face each other,
A battery pack, wherein the surfaces opposite to the terminals of the first battery group and the second battery group face the inner surface of the housing and do not face the other battery groups. In the battery pack according to claim 1,
The first battery group and the housing are in contact with each other via a pressure binding jig, and the second battery group and the housing are in contact with each other via a pressure binding jig. A battery pack characterized by: In the battery pack according to claim 1,
A battery pack, wherein the first battery group and the housing are in direct contact, and the second battery group and the housing are in direct contact. In the battery pack according to claim 1,
A battery pack, wherein an electrical component is arranged in a space between a surface on which the external terminals of the first battery group are arranged and a surface on which the external terminals of the second battery group are arranged. .

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