Patent Application
20240213571
This nonprovisional application is based on Japanese Patent Application No. 2022-205360 filed on Dec. 22, 2022 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.
The present technology relates to an electric device and a battery pack system.
As a structure for promoting radiation of heat from an electric component in an electric device, a structure described in each of Japanese Utility Model Laying-Open No. H05-008947 and Japanese Patent Laying-Open No. 2000-125448 has been conventionally known, for example.
Even when resistance of a conductive portion of an electric component is relatively small in an electric device in which a large amount of current flows, a large amount of heat can be generated in the resistance portion. The conventional heat radiation structure is not necessarily sufficient from the viewpoint of cooling to deal with a large amount of generated heat.
It is an object of the present technology to provide an electric device and a battery pack system so as to attain high efficiency of cooling of an electric component. The present technology provides the following electric device and battery pack system.
[1] An electric device comprising: a housing composed of a metal; an electric component provided to be separated from the housing; and a bus bar connected to the electric component, wherein the bus bar includes a first portion connected to the electric component, and a second portion provided at a position close to the housing with respect to the first portion, and a heat transfer portion having an insulating property and a thermal conductivity higher than a thermal conductivity of air is provided between the second portion of the bus bar and the housing.
[2] The electric device according to [1], wherein the electric component includes a fuse element or a relay element.
[3] The electric device according to [1] or [2], wherein the heat transfer portion has a thermal conductivity of 1.0 W/m·K or more.
[4] The electric device according to any one of [1] to [3], wherein the heat transfer portion is constituted of a sheet-shaped member.
[5] The electric device according to any one of [1] to [4], wherein the heat transfer portion includes an acrylic-based resin.
[6] The electric device according to any one of [1] to [5], wherein the electric component has a first terminal and a second terminal, the bus bar has a first bus bar connected to the first terminal and a second bus bar connected to the second terminal, and each of the first bus bar and the second bus bar includes the first portion and the second portion.
[7] The electric device according to any one of [1] to [6], wherein the bus bar is constituted of a plate-shaped member, and the first portion and the second portion are formed by performing a bending process onto the plate-shaped member.
[8] The electric device according to any one of [1] to [7], further comprising a cooling plate attached to the housing, wherein the cooling plate has a coolant path.
[9] The electric device according to [8], wherein a clearance is formed between the housing and the cooling plate, a filling material having a thermal conduction property is provided in the clearance, and the heat transfer portion is provided at a position overlapping with the clearance.
[10] A battery pack system comprising: a battery pack including a plurality of battery cells; and the electric device according to any one of [1] to [9], the electric device being electrically connected to the battery pack.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
Hereinafter, embodiments of the present technology will be described. It should be noted that the same or corresponding portions are denoted by the same reference characters, and may not be described repeatedly.
It should be noted that in the embodiments described below, when reference is made to number, amount, and the like, the scope of the present technology is not necessarily limited to the number, amount, and the like unless otherwise stated particularly. Further, in the embodiments described below, each component is not necessarily essential to the present technology unless otherwise stated particularly. Further, the present technology is not limited to one that necessarily exhibits all the functions and effects stated in the present embodiment.
It should be noted that in the present specification, the terms “comprise”, “include”, and “have” are open-end terms. That is, when a certain configuration is included, a configuration other than the foregoing configuration may or may not be included.
Also, in the present specification, when geometric terms and terms representing positional/directional relations are used, for example, when terms such as “parallel”, “orthogonal”, “obliquely at 45°”, “coaxial”, and “along” are used, these terms permit manufacturing errors or slight fluctuations. In the present specification, when terms representing relative positional relations such as “upper side” and “lower side” are used, each of these terms is used to indicate a relative positional relation in one state, and the relative positional relation may be reversed or turned at any angle in accordance with an installation direction of each mechanism (for example, the entire mechanism is reversed upside down).
In the present specification, the term “battery” is not limited to a lithium ion battery, and may include other batteries such as a nickel-metal hydride battery and a sodium ion battery.
In the present specification, the term “battery cell” is not necessarily limited to a prismatic battery cell and may include a cell having another shape, such as a cylindrical battery cell, a pouch battery cell, or a blade battery cell. The “battery cell” can be mounted on vehicles such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a battery electric vehicle (BEV). It should be noted that the use of the “battery cell” is not limited to the use in a vehicle.
In the example of
Electric pack 200 has connectors 211 on the positive electrode side and connectors 212 on the negative electrode side. Of connectors 211, 212, connectors 211A, 211B are each connected to a load on the vehicle side via interface 300, whereas connectors 211B, 212B are each connected to charging/discharging line 10.
Electric pack 200 further has connectors 213. Of connectors 213, a connector 213A is connected to a device on the vehicle side via interface 300, whereas a connector 213B is connected to signal line 20 on the system side.
Battery cell 1 illustrated in
Housing 120 has a rectangular parallelepiped shape and forms an external appearance of battery cell 1. Housing 120 includes: a case body 120A that accommodates an electrode assembly (not shown) and an electrolyte solution (not shown); and a sealing plate 120B that seals an opening of case body 120A. Sealing plate 120B is joined to case body 120A by welding.
Housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and two third side surfaces 125.
Upper surface 121 is a flat surface orthogonal to a Z axis direction (third direction) orthogonal to the Y axis direction and the X axis direction. Electrode terminals 110 are disposed on upper surface 121. Lower surface 122 faces upper surface 121 along the Z axis direction.
Each of first side surface 123 and second side surface 124 is constituted of a flat surface orthogonal to the Y axis direction. Each of first side surface 123 and second side surface 124 has the largest area among the areas of the plurality of side surfaces of housing 120. Each of first side surface 123 and second side surface 124 has a rectangular shape when viewed in the Y axis direction. Each of first side surface 123 and second side surface 124 has a rectangular shape in which the X axis direction corresponds to the long-side direction and the Z axis direction corresponds to the short-side direction when viewed in the Y axis direction.
A plurality of battery cells 1 are stacked such that first side surfaces 123 of battery cells 1, 1 adjacent to each other in the Y direction face each other and second side surfaces 124 of battery cells 1, 1 adjacent to each other in the Y axis direction face each other. Thus, positive electrode terminals 111 and negative electrode terminals 112 are alternately arranged in the Y axis direction in which the plurality of battery cells 1 are stacked.
Gas-discharge valve 130 is provided in upper surface 121. When the temperature of battery cell 1 is increased (thermal runaway) and internal pressure of housing 120 becomes more than or equal to a predetermined value due to gas generated inside housing 120, gas-discharge valve 130 discharges the gas to outside of housing 120.
Each of battery packs 100 shown in
Each of
Fuse elements 230, main relays 240, current sensors 250, pre-charging resistor 260, and pre-charging relay 270 are electric components accommodated in the inner space of case member 200A, and are connected to the outside of electric pack 200 via connectors 211A, 211B, 212A, 212B. Control board 220 is also an electric component accommodated in the inner space of case member 200A, and is connected to the outside of electric pack 200 via connectors 213A, 213B. Other electric components not shown in
As shown in
Fuse element 230 has a terminal 231A (first terminal) and a terminal 231B (second terminal). A bus bar 290A (first bus bar) is connected to terminal 231A, and a bus bar 290B (second bus bar) is connected to terminal 231B.
Bus bars 290A, 290B respectively include: first portions 291A, 291B each connected to fuse element 230; second portions 292A, 292B provided at positions close to housing 201A with respect to first portions 291A, 291B; and third portions 293A, 293B provided at positions away from housing 201A with respect to second portions 292A, 292B. The heights (separation heights) of first portions 291A, 291B from housing 201A may be substantially the same as or different from the heights (separation heights) of third portions 293A, 293B from housing 201A.
Each of first portions 291A, 291B, second portions 292A, 292B, and third portions 293A, 293B of bus bars 290A, 290B can be formed by performing a bending process onto a plate-shaped member composed of a metal. It should be noted that a bus bar constituted only of first portions 291A, 291B and second portions 292A, 292B may be formed without forming third portions 293A, 293B.
Between each of second portions 292A, 292B of bus bars 290A, 290B and housing 201A, a heat transfer member 200D (heat transfer portion) having an insulating property and a thermal conductivity higher than that of air is provided. Heat transfer member 200D is preferably composed of a material having thermal conductivity and dielectric strength each having a value equal to or more than a certain value.
For example, heat transfer member 200D preferably has a thermal conductivity of about 1.0 W/m·K or more. As an example, heat transfer member 200D is constituted of a sheet-shaped member having elasticity and including an acrylic-based resin (thermally conductive acrylic-based heat-radiation material). More specifically, heat transfer member 200D may be formed using 6500H provided by 3M Company.
It should be noted that the configuration of heat transfer member 200D is not limited to the one described above, and heat transfer member 200D may be composed of a gel-like material, for example.
With an increase in size of battery pack 100 or the battery module, a large amount of current is likely to flow in electric pack 200 connected to battery pack 100. Even when resistance of a conductive portion of the electric component such as fuse element 230 is relatively small in electric pack 200 in which a large amount of current flows, a large amount of heat can be generated in the resistance portion.
To address this, in electric pack 200 according to the present embodiment, heat generated in fuse element 230 is transferred from fuse element 230 to housing 201A composed of a metal via bus bars 290A, 290B and heat transfer members 200D, thereby efficiently radiating the heat. As a result, the electric component such as fuse element 230 can be efficiently cooled. Further, since the above-described mounted structure can be obtained only by processing bus bars 290A, 290B and installing heat transfer member 200D, the structure of electric pack 200 is suppressed from being complicated.
Gap filler 200C may be in the form of a paste or may be in the form of a sheet obtained by curing the paste. Gap filler 200C preferably has a thermal conductivity comparable to or higher than that of heat transfer member 200D.
In the example shown in
Although the embodiments of the present invention have been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-205360 | Dec 2022 | JP | national |
