Battery pack and lower housing

Abstract

In conventional battery packs, there is a problem of not being able to control the outflow direction of the thermal conductive agent. One aspect of the battery pack according to the present invention includes multiple battery cells, a battery housing portion housing the multiple battery cells, and a heat sink plate disposed with its heat dissipation surface exposed on the outside of the battery housing portion. The battery housing portion has the following formed on its bottom surface: multiple thermal conductive agent filling portions, which are formed to fill a cell structure portion with thermal conductive agent and arranged in the row direction of the stacked battery cells. The cell structure portion is formed at a position corresponding to the electrode components attached to the battery cells. The cell structure portion is configured to expose the top surface of a heat dissipation protrusion formed on the back side of the heat dissipation surface and to form multiple walls in a manner that surrounds the area of ​​the exposed top surface of the heat dissipation protrusion; and a channel, which is formed to extend in the row direction in a region adjacent to the multiple thermal conductive agent filling portions. Among the multiple thermal conductive agent filling portions, the thermal conductive agent control wall facing the channel is formed to the lowest degree.

Description

Technical Field

[0001] The present invention relates to a battery pack and a lower housing, for example, housing multiple battery cells. Background Technology

[0002] With the increasing performance of batteries, ensuring their heat dissipation has become a problem. Therefore, Japanese Patent Application Publication No. 2024-50379 discloses a technology related to heat dissipation in a battery pack that houses multiple battery cells.

[0003] The battery pack disclosed in Japanese Patent Application Publication No. 2024-50379 includes: a plurality of secondary batteries having external terminals at their bottom; a busbar assembly having a connecting substrate electrically connected to and conducting heat from the external terminals of each of the secondary batteries; a housing having the busbar assembly disposed at the bottom and arranging the plurality of secondary batteries and connecting them to the busbar assembly for housing; and a heat dissipation member disposed on the outside of the housing for dissipating heat from the connecting substrate to the outside of the housing. Summary of the Invention

[0004] In the battery pack described in Japanese Patent Application Publication No. 2024-50379, a thermally conductive agent is coated to improve the thermal conductivity between the bus assembly and the heat dissipation component. However, the technology described in Patent Document 1 has the following problem: when the bus assembly is pressed onto the heat dissipation component, the direction of the coated thermally conductive agent outflow cannot be controlled.

[0005] The present invention was made in view of the above circumstances, and its object is to control the outflow direction of the thermal conductive agent when the electrode components attached to the battery cell are pressed onto the heat dissipation member.

[0006] One aspect of the battery pack according to the present invention includes a plurality of battery cells, a battery housing portion for housing the plurality of battery cells, and a heat sink plate disposed with its heat dissipation surface exposed on the outside of the battery housing portion. The battery housing portion has the following on its bottom surface: a plurality of thermally conductive filler portions formed to fill a cell structure portion with thermally conductive material and arranged in the row direction of the battery cell stack. The cell structure portion is formed at a position corresponding to the electrode components attached to the battery cells. The cell structure portion is configured to expose the top surface of a heat dissipation protrusion formed on the back side of the heat dissipation surface and has a plurality of walls formed in a manner that surrounds the area of ​​the exposed top surface of the heat dissipation protrusion; and a channel formed to extend along the row direction in a region adjacent to the plurality of thermally conductive filler portions. Among the plurality of thermally conductive filler portions, the thermally conductive dosage control wall facing the channel is formed to be the lowest.

[0007] One aspect of the lower housing according to the present invention is a lower housing of a battery pack housing multiple battery cells. The lower housing has a battery housing portion housing the multiple battery cells and a heat dissipation plate disposed on the outside of the battery housing portion with a heat dissipation surface exposed. The battery housing portion has the following on its bottom surface: multiple thermally conductive filler portions formed to fill a cell structure portion with thermally conductive material and arranged in the row direction of the battery cell stack. The cell structure portion is formed at a position corresponding to the electrode components attached to the battery cells. The cell structure portion is configured to expose the top surface of a heat dissipation protrusion formed on the back side of the heat dissipation surface and has multiple walls formed in a manner that surrounds the area of ​​the exposed top surface of the heat dissipation protrusion; and a channel formed to extend along the row direction in a region adjacent to the multiple thermally conductive filler portions. Among the multiple thermally conductive filler portions, the thermally conductive dosage control wall facing the channel is formed to be the lowest.

[0008] According to the battery pack and lower housing of the present invention, when the electrode components attached to the battery cell are pressed onto the heat dissipation member, the outflow direction of the heat-conducting agent can be controlled.

[0009] The above and other objects, features and advantages of this disclosure will be more fully understood from the following detailed description and accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the battery pack involved in Embodiment 1.

[0011] Figure 2 This is a schematic diagram of the heat sink involved in Embodiment 1.

[0012] Figure 3 This is a schematic diagram of the lower housing according to Embodiment 1.

[0013] Figure 4 This is an enlarged view of the heat-conducting agent filling part according to Embodiment 1.

[0014] Figure 5 It is along Figure 1 A cross-sectional view of the battery pack with VV lines.

[0015] Figure 6 It is along Figure 1 Cross-sectional view of the battery pack on the VI-VI line.

[0016] Figure 7 It is along Figure 1 Cross-sectional view of the battery pack on line VII-VII.

[0017] Figure 8 This is a diagram illustrating an example of battery cell storage when using L-shaped electrode terminals. Detailed Implementation

[0018] For clarity, appropriate omissions and simplifications have been made to the following descriptions and figures. It should be noted that the same reference numerals are used for the same elements in the figures, and repeated descriptions are omitted where necessary.

[0019] Implementation Method 1 Figure 1 A schematic diagram of the battery pack involved in Embodiment 1 is shown. (As shown) Figure 1 As shown, in embodiment 1, the battery pack 1 has multiple battery units 3 housed in the lower housing 2. The battery units 3 housed in the lower housing 2 are pressed by the vibration suppression plate 4 onto the bottom surface of the lower housing 2, thereby fixing the battery units 3 inside the lower housing 2. Figure 1 The image shows bolts 14 used to secure the vibration damping plate 4 to the lower housing 2.

[0020] It should be noted that, in Figure 1 In the illustration, to illustrate the state of the battery cells 3 housed in the lower housing 2, two battery cells 3 are shown as a group housed in the lower housing 2. However, the battery cells 3 housed in the lower housing 2 are housed in the lower housing 2 after being assembled into a battery stack, with each battery stack being housed in a row of battery cells 3. Figure 1 The example shows a structure with 14 battery cells 3) connected by a busbar component. Furthermore, in... Figure 1 The image shows an example of two battery stacks arranged in two columns within a lower housing 2, but the number of columns of the battery stacks housed in the lower housing 2 can be appropriately varied according to the specifications of the battery pack 1. In the following description, the direction in which the battery cells 3 are stacked is referred to as the row direction, and the direction in which the battery stacks are arranged is referred to as the column direction, which is the direction orthogonal to the row direction.

[0021] The lower housing 2, as an embedded component, is composed of a heat sink 20 (described later) and a lower housing tab 10 integrally molded from resin. In the lower housing tab 10, the heat sink 20 is configured such that its heat dissipation surface is exposed to the outside of the battery storage section. Furthermore, by providing a partition 11 to the lower housing tab 10, the lower housing tab 10 is divided into a battery storage section 12 and a junction box storage section 13. The battery storage section 12 houses multiple battery cells 3. In addition, the junction box storage section 13 is provided with a circuit for inputting / outputting power to the multiple battery cells 3, i.e., a junction box. Figure 1The junction box itself is omitted. At the bottom of the junction box housing 13, a thermally conductive agent is filled in the pool structure portion, which is formed at a position corresponding to the electrode components of the junction box. The pool structure portion is configured such that the top surface of the heat dissipation protrusion 22 formed on the back side of the heat dissipation surface of the heat sink 20 is exposed, and multiple walls are formed in such a way as to surround the area where the top surface of the heat dissipation protrusion 22 is exposed.

[0022] In addition, such as Figure 1 As shown, multiple thermally conductive agent filling portions and channels are formed on the bottom surface of the battery housing 12. The multiple thermally conductive agent filling portions are each formed to fill a cell structure portion with thermally conductive agent and are arranged in the row direction of the stacked battery cells. The cell structure portion is formed at a position corresponding to the electrode components attached to the battery cell 3, and is configured such that the top surface of the heat dissipation protrusion 21 formed on the back side of the heat dissipation surface of the heat dissipation plate 20 is exposed, and multiple walls are formed to surround the area where the top surface of the exposed heat dissipation protrusion 21 is exposed. The channels are formed to extend in the row direction in the area adjacent to the multiple thermally conductive agent filling portions. The structure of the thermally conductive agent filling portions will be described in detail below.

[0023] Here, the adhesion between the thermal conductive agent and the heat dissipation protrusion 21 and the electrodes of the battery cell 3 is important. To ensure insulation, a material with high thermal conductivity inorganic filler added to the resin can be used. For example, a material based on silicone resin (polyalkylsiloxane) with added inorganic filler can be used. Alternatively, a material based on liquid crystal polymer with added inorganic filler can also be used. Furthermore, an acrylic resin-based material with added inorganic filler can also be used. Thus, the material of the thermal conductive agent is selected or combined considering thermal conductivity, strength, insulation, etc.

[0024] Figure 2 A schematic diagram of the heat sink 20 according to Embodiment 1 is shown. Figure 2 As shown, multiple heat dissipation protrusions 21 are formed on the heat sink 20 at positions corresponding to the electrode components attached to the battery cell 3. Furthermore, in Figure 2 In the example shown, column isolation walls 23 are formed to divide the battery stack into columns. Additionally, in... Figure 2 In the example shown, a heat dissipation protrusion 22 is formed in the area corresponding to the junction box.

[0025] It should be noted that the heat sink 20 is not limited to the size corresponding to the battery storage section 12. By setting it to a size corresponding to both the battery storage section 12 and the junction box storage section 13, not only can the heat dissipation force for the battery cells be improved, but also the heat dissipation force for the junction box can be improved. The lower housing protrusion 10 is molded from resin integrally with the heat sink 20.

[0026] Figure 3 A schematic diagram of the lower housing 2 according to Embodiment 1 is shown. Figure 3 As shown, in the heat sink 20, on the bottom surface of the lower housing protrusion 10 and the bottom surface of the area of ​​the battery storage portion 12, the top surface of the heat dissipation protrusion 21 is exposed, and a pool structure portion with multiple walls is formed in a manner that surrounds the area where the top surface of the heat dissipation protrusion 21 is exposed. This pool structure portion is formed at a position corresponding to the electrode component attached to the battery cell 3. The pool structure portion is filled with a thermally conductive agent, and the pool structure portion is formed in a row direction of the battery cell stack. The passage is formed to extend in the row direction in the area adjacent to the multiple thermally conductive agent filling portions.

[0027] Here, the battery cell 3 according to Embodiment 1 has a dual-cell structure in which two electrode bodies are housed in a single housing. Therefore, in addition to the positive and negative terminals, the battery cell 3 also has a middle terminal cover covering the intermediate terminal, which connects the two electrode bodies housed in the housing. This intermediate terminal cover is, for example, formed from a metal with a thermal conductivity higher than that of resin that has undergone an insulating process. Therefore, as... Figure 3 As shown, in the lower housing 2 according to Embodiment 1, multiple thermally conductive fillers form a first thermally conductive filler 16a and a second thermally conductive filler 16b. The first thermally conductive filler 16a has a pool structure portion with a shape matching the shape of a busbar component that connects adjacent electrodes of different polarities in multiple battery cells. The second thermally conductive filler 16b has a pool structure portion with a shape matching the shape of an intermediate terminal cover that connects two electrode bodies housed in a housing. Figure 3 In the figure, the heat dissipation protrusion 21 exposed in the first thermal conductive filler 16a is designated as 21a, and the heat dissipation protrusion 21 exposed in the second thermal conductive filler 16b is designated as 21b.

[0028] In addition, such as Figure 3 As shown, channels 15a and 15b are shown in the battery storage section 12, which are formed to extend in a row direction in a region adjacent to multiple thermally conductive filler sections. Figure 3 The example shown illustrates a channel 15a formed between the first thermally conductive filler portion 16a and the second thermally conductive filler portion 16b, and a channel 15b formed between the segmented second thermally conductive filler portions 16b. In the lower housing 2 according to Embodiment 1, the outflow direction of the thermally conductive agent is controlled by the structure of the wall surrounding the heat dissipation protrusions in the first thermally conductive filler portion 16a and the second thermally conductive filler portion 16b.

[0029] So, Figure 4 An enlarged view of the thermally conductive filler portion according to Embodiment 1 is shown. Figure 4As shown, the first thermally conductive filler portion 16a, which surrounds the heat dissipation protrusion 21a by a wall, has a first wall 30, a second wall 31, a thermally conductive dosage control wall 32, and a housing sidewall 33, in a manner that surrounds the top surface of the exposed heat dissipation protrusion 21a. Furthermore, in Figure 4 In the diagram, a positioning protrusion 34 is shown at the location where it contacts the thermal conductivity control wall 32. The positioning protrusion 34 is used to determine the position of the housing sidewall 33. That is, the first thermal conductivity filling part has the shape of a pool structure portion that matches the shape of the busbar component.

[0030] like Figure 4 As shown, the first thermally conductive agent filling portion 16a has a first wall 30 and a second wall 31 disposed at opposite positions in the row direction. Furthermore, the first thermally conductive agent filling portion 16a has a thermal conductivity dose control wall 32 and a housing sidewall 33 disposed at opposite positions in the column direction. Additionally, the thermal conductivity dose control wall 32 is formed facing the channel 15a. And, as... Figure 4 In the example shown, the first wall 30 has the highest height, the thermal conductivity control wall 32 has the lowest height, and the second wall 31 has a height that is intermediate between the first wall 30 and the thermal conductivity control wall 32. With this wall height setting, thermal conductivity filling the first thermal conductivity filling portion 16a in a manner that covers the top surface of the heat dissipation protrusion 21a, and overflowing when the busbar component of the battery cell 3 is pressed, will flow over the thermal conductivity control wall 32 and into the channel 15a. Furthermore, by making the height of the second wall 31 lower than that of the first wall 30, it is easier to lead wiring (e.g., flexible printed wiring) connected to voltage detection elements or the like connected to the busbar component to the channel 15a.

[0031] Furthermore, the second thermal conductive agent filling section 16b is sized in the row direction by a plurality of third walls 35 arranged along the row direction, and forms two fourth walls 36 opposite each other in the column direction. The height of the fourth walls 36 is set lower than that of the third walls 35. Therefore, when the middle terminal cover of the battery cell 3 is pressed, the thermal conductive agent overflowing from the second thermal conductive agent filling section 16b flows across the fourth walls 36 and out into the channel 15a or into the channel 15b located in the area opposite to the channel 15a, separated by the second thermal conductive agent filling section 16b. It should be noted that the width of the second thermal conductive agent filling section 16b in the row direction only needs to match the shape of the periphery of the middle terminal cover of the battery cell 3, and does not need to be constant.

[0032] Flexible printed wiring (FPC) is disposed between adjacent second thermally conductive filler portions 16b along the column direction in channel 15b. By having a structure capable of arranging the flexible printed wiring in such a position, in the battery pack 1, the channel 15b is positioned at the center of each column direction of the battery housing portion 12 divided by the column partition wall 23, thus unifying the column-direction length of the battery cells 3 within the battery stack. Furthermore, the flexible printed wiring is connected to a temperature measurement circuit for measuring the temperature inside the housing.

[0033] Next, the cross-sectional structure of the first thermally conductive filler portion 16a will be described. Then, Figure 5 Show along Figure 1 A cross-sectional view of battery pack 1 on the VV line. Figure 6 Show along Figure 1 A cross-sectional view of battery pack 1 on the VI-VI line. It should be noted that... Figure 5 and Figure 6 The image shows a cross-sectional view of the battery cell 3 housed within the lower housing 2. Figure 5 and Figure 6 As shown, with the thermally conductive agent 60 filled in the first thermally conductive agent filling section 16a, the battery cell 3 is housed in the lower housing 2 in a manner that accommodates the busbar component 50. At this time, in the battery stack, electrodes of different polarities of each battery cell 3 are arranged alternately. Therefore, according to safety regulations, the distance between the surfaces connecting electrodes of different polarities (creep distance) needs to be set to a specified insulation distance or greater. Taking this creepage distance into account, by having the first wall 30 and the second wall 31, the creepage distance can be made longer than the horizontal distance between the electrodes of the battery cell 3 (for example, the horizontal distance in the attached figure).

[0034] In addition, such as Figure 5 and Figure 6 As shown, the battery cell 3 is composed of a cell housing 40 and a cell housing cover 41. Furthermore, each of the cell housings 40 of the plurality of battery cells 3 has a recess (e.g., recesses 44, 45 and 47, 48) on both sides of the portion adjacent in the longitudinal direction of the positive terminal 43 and the negative terminal 46 in the lower cell housing where the electrodes are housed. This recess only needs to be provided on at least one of the portions adjacent in the longitudinal direction of the positive terminal 43 and the negative terminal 46. By having this recess, the creepage distance along the surfaces of the cell housing 40 and the cell housing cover 41 can be made longer than the horizontal distance between the electrodes of the battery cell 3.

[0035] In this way, by providing the first wall 30 and the second wall 31 of the first thermally conductive filling portion 16a, as well as the recesses 44, 45, 47, and 48, the creepage distance can be made longer than the horizontal distance between the electrodes of the battery cell 3. In other words, by providing the first wall 30 and the second wall 31 of the first thermally conductive filling portion 16a, as well as the recesses 44, 45, 47, and 48, in the battery pack 1 according to Embodiment 1, the battery cells 3 can be housed at a higher density while ensuring an appropriate insulation distance, thereby reducing the volume of the battery pack 1.

[0036] Next, the cross-sectional structure of the second thermal conductive agent filling part 16b will be described. Figure 7 Show along Figure 1 A cross-sectional view of battery pack 1 on line VII-VII. (See diagram below.) Figure 7 As shown, in the lower housing 2 according to Embodiment 1, the battery cell 3 is housed such that the intermediate terminal cover 49 of the battery cell 3 is embedded in the second thermally conductive agent filling portion 16b filled with thermally conductive agent 60. In this case, by having a third wall 35, the insulation distance between the intermediate terminals of the battery cell 3 can be made longer than the horizontal distance between the electrodes of the battery cell 3. Furthermore, in... Figure 7 In the example shown, the second thermally conductive filler portion 16b with a length of W1 in the row direction is arranged alternately with the second thermally conductive filler portion 16b with a length of W2 that is longer than W1 in the row direction. This is because the unit housing 40 is formed such that the width of the positive terminal portion connected to the intermediate terminal is different from the width of the negative terminal portion.

[0037] According to the above description, in the battery pack 1 according to Embodiment 1, by minimizing the height of the heat conduction control wall 32 or the fourth wall 36 facing the channels 15a and 15b in the wall surrounding the exposed portion of the heat dissipation protrusion in the heat conduction filling section, the heat conduction agent filled in the heat conduction filling section can preferentially overflow into the areas (e.g., channels 15a and 15b) arranged in the row direction of each heat conduction filling section. As a result, in the battery pack 1, the overflowing heat conduction agent can make the creepage distance between the battery cells 3 arranged in the row direction longer than the horizontal distance between the electrodes of the battery cells 3, and the battery cells 3 can be housed in the battery pack 1 with a higher density.

[0038] In addition, in battery pack 1, the overflowed thermal conductive agent can be easily cleaned by allowing it to overflow into channels 15a and 15b.

[0039] Furthermore, in the battery pack 1, by setting the height of the second wall 31 in the first thermal conductive agent filling section 16a to the intermediate height between the first wall 30 and the thermal conductive agent dosage control wall 32, it is possible to ensure the outlet channel of the wiring connected to the busbar component and to control the overflow direction of the thermal conductive agent.

[0040] In addition, in the battery pack 1, by providing the same thermal conductive filler as the battery storage section 12 in the area of ​​the junction box storage section 13, the heat dissipation through the busbar components provided in the junction box can be ensured, thereby improving the overall heat dissipation performance of the battery pack 1.

[0041] Furthermore, in the battery cell 3 housed in the battery pack 1, the recesses 44, 45, 47, and 48 provided on both sides of the positive terminal 43 and the negative terminal 46 make the creepage distance along the surface of the cell housing longer than the horizontal distance between the electrodes of the battery cell 3, thus enabling the battery cell 3 to be housed in the battery pack 1 at a higher density.

[0042] Furthermore, the heat dissipation structure of battery pack 1 can also accommodate battery cells 3 with L-shaped electrode terminals formed on two consecutive surfaces. Therefore, Figure 8 The diagram illustrates an example of battery cell storage when using L-shaped electrode terminals. Figure 8 In the examples shown, the L-shaped electrode terminals 70 are housed in various forms of lower housing 2 via busbar components 71. In the first example, a battery cell 3 with L-shaped electrode terminals 70 is shown housed within... Figure 1 A schematic diagram of the battery pack 1 in the lower housing 2 is shown. In a second example, a schematic diagram of the battery pack 1 with battery cells 3 having L-shaped electrode terminals 70 housed in a lower housing 2 having a heat sink 20 arranged on the sidewalls is shown. This second example is effective for specifications with stricter height restrictions than the first example. In a third example, a schematic diagram of the battery pack 1 with battery cells 3 having L-shaped electrode terminals 70 housed in a lower housing 2 having a heat sink 20 covering both the bottom and sidewalls is shown. This third example is effective for specifications requiring higher heat dissipation performance than the first example. Thus, by modifying the arrangement or shape of the heat sink 20, a battery pack 1 that matches the longitudinal and transverse dimensions of the battery pack and the required heat dissipation performance can be constructed.

[0043] It should be noted that the present invention is not limited to the above embodiments, and appropriate changes can be made without departing from the spirit of the invention.

Claims

1. A battery pack, the battery pack comprising: Multiple battery cells; A battery storage section for accommodating the plurality of battery cells; and A heat sink plate is configured with its heat dissipation surface exposed on the outside of the battery housing. The battery storage section has the following features on its bottom surface: Multiple thermally conductive fillers are formed to fill a cell structure portion with thermally conductive agent and are arranged in the row direction of the stacked battery cells. The cell structure portion is formed at a position corresponding to the electrode components attached to the battery cells. The cell structure portion is configured such that the top surface of a heat dissipation protrusion formed on the back side of the heat dissipation surface is exposed, and multiple walls are formed to surround the exposed top surface area of ​​the heat dissipation protrusion. The channel is formed to extend along the row direction in the region adjacent to the plurality of thermally conductive fillers. Of the plurality of thermally conductive fillers, the thermally conductive dose control wall facing the channel is formed to the lowest degree among the plurality of walls.

2. The battery pack according to claim 1, wherein, The battery storage section is molded from resin components, and the heat dissipation plate is molded from metal components.

3. The battery pack according to claim 1, wherein, The battery cell has a dual-cell structure in which two electrodes are housed in a single housing. The plurality of thermally conductive filler portions have: A first thermally conductive filler portion having a cell structure portion with a shape matching that of a busbar component, the busbar component connecting adjacent electrodes of different polarities in the plurality of battery cells; as well as A second thermally conductive filler portion, having a pool structure portion shaped to match the shape of the intermediate terminal cover covering the intermediate terminal, wherein the intermediate terminal connects to two electrode bodies housed within a housing. The first thermal conductive agent filling portion and the second thermal conductive agent filling portion are disposed in the column direction orthogonal to the row direction, separated by the channel.

4. The battery pack according to claim 3, wherein, The first thermal conductive agent filling portion has: The first and second walls are positioned at opposite locations in the row direction. The second wall is formed to be lower than the first wall and higher than the thermal conductivity dose control wall.

5. The battery pack according to claim 1, wherein, The plurality of battery cells each have a recess on at least one of the adjacent portions of the positive and negative terminals in the lower housing of the cell containing the electrode body along the row direction.

6. A lower housing for a battery pack housing multiple battery cells, the lower housing having: A battery storage section for accommodating the plurality of battery cells; and A heat sink plate is configured with its heat dissipation surface exposed on the outside of the battery housing. The battery storage section has the following features on its bottom surface: Multiple thermally conductive fillers are formed to fill a cell structure portion with thermally conductive agent and are arranged in the row direction of the stacked battery cells. The cell structure portion is formed at a position corresponding to the electrode components attached to the battery cells. The cell structure portion is configured such that the top surface of a heat dissipation protrusion formed on the back side of the heat dissipation surface is exposed, and multiple walls are formed to surround the exposed top surface area of ​​the heat dissipation protrusion. The channel is formed to extend along the row direction in the region adjacent to the plurality of thermally conductive fillers. Of the plurality of thermally conductive fillers, the thermally conductive dose control wall facing the channel is formed to the lowest degree among the plurality of walls.

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