Battery pack

Abstract

To provide a battery pack that allows for smooth insertion of positioning pins and reliable positioning of the battery module relative to the current collector plate without complicating or increasing the size of the structure. [Solution] The battery pack comprises a battery module, a current collector plate joined to the battery module via a conductive adhesive, and a positioning pin attached to the lower surface of the battery module, which is inserted into a hole provided in the current collector plate to position the battery module relative to the current collector plate, wherein the positioning pin has a shape that satisfies equation (1) when F0 is the weight of the battery module, R is the reaction force of the conductive adhesive, θ is the angle of the positioning pin, and μ is the coefficient of friction.

Description

Technical Field

[0001] The present disclosure relates to a battery pack.

Background Art

[0002] Patent Document 1 discloses a positioning pin for determining the position of an electrical connection terminal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when stacking a battery module and a current collector plate (cooler), both are joined using a conductive adhesive. Since, for example, a metal filler is added to this conductive adhesive, the viscosity is particularly high before curing. Therefore, for example, in order to smoothly insert a positioning pin into a hole provided in the current collector plate, it is necessary to make the angle of the positioning pin an acute angle, and for that purpose, it is necessary to lengthen the positioning pin, and as a result, there is a risk that the structure of the battery pack will become complicated and large-sized.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a battery pack that can smoothly insert a positioning pin and reliably position a battery module with respect to a current collector plate without complicating and enlarging the structure.

Means for Solving the Problems

[0006] The battery pack according to this disclosure comprises a battery module, a current collector plate joined to the battery module via a conductive adhesive, and a positioning pin attached to the lower surface of the battery module and inserted into a hole provided in the current collector plate to position the battery module relative to the current collector plate, wherein the positioning pin has a shape that satisfies the following formula (1), where F0 is the weight of the battery module, R is the reaction force of the conductive adhesive, θ is the angle of the positioning pin, and μ is the coefficient of friction.

number

[0007] According to this disclosure, by giving the positioning pin a shape that satisfies a predetermined relation, even when a highly viscous conductive adhesive is used to join the battery module and the current collector plate, the positioning pin can be smoothly inserted without complicating or increasing the size of the structure, and the positioning of the battery module relative to the current collector plate can be reliably achieved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows a schematic configuration of positioning pins in a battery pack according to this embodiment. [Figure 2] Figure 2 is a graph illustrating the relationship between the thickness L of the conductive adhesive and the reaction force R in the battery pack according to the embodiment. [Figure 3] Figure 3 is a diagram illustrating the relationship between the angle of the positioning pin and the force acting on the current collector plate in a battery pack according to this embodiment. [Figure 4] Figure 4 shows a schematic configuration of a modified example of the positioning pins in the battery pack according to the embodiment. [Modes for carrying out the invention]

[0009] A battery pack according to the embodiments of this disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that are easily replaceable or substantially identical to those that are replaceable by a person skilled in the art.

[0010] The battery pack according to this embodiment can be used as a battery for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs).

[0011] As shown in Figure 1, the battery pack according to this embodiment comprises a battery module 1, a conductive adhesive 2, a current collector plate (cooler) 3, and a positioning pin 4. Note that Figure 1 only shows the components necessary for realizing the battery pack according to this embodiment, and other components are omitted from the illustration.

[0012] Battery module 1 is composed of multiple battery cells. These battery cells are, for example, rechargeable batteries such as lithium-ion batteries. Furthermore, if the battery cells are composed of lithium-ion batteries, they may be either liquid-based batteries or all-solid-state batteries.

[0013] The conductive adhesive 2 is used to bond the battery module 1 and the current collector plate 3. This conductive adhesive 2 contains, for example, a metal filler.

[0014] The current collector plate 3 also functions as a cooler and is composed of, for example, a lower case that houses the various components of the battery pack. This current collector plate 3 is joined to the battery module 1 via a conductive adhesive 2. The current collector plate 3 is also provided with a hole 31 for inserting a positioning pin 4. The diameter of this hole 31 is formed to be larger than the diameter of the positioning pin 4.

[0015] The positioning pin 4 is attached to the lower surface of the battery module 1. Also, the positioning pin 4 is inserted into the hole 31 provided in the current collector plate 3, thereby positioning the battery module 1 with respect to the current collector plate 3. Further, the positioning pin 4 has a shape that satisfies the following formula (1), where F0 is the self-weight of the battery module 1, R is the reaction force of the conductive adhesive 2, θ is the angle of the positioning pin 4, and μ is the coefficient of friction.

Equation

[0016] Specifically, as shown in FIG. 1, θ in the above formula (1) indicates the angle of the lower part (taper part) of the positioning pin 4 with respect to the upper surface of the current collector plate 3. Also, the lower part of the positioning pin 4 is, for example, conical as a whole, and the angle of this cone is θ.

[0017] Here, when mounting the battery module on the current collector plate, the conductive adhesive applied between the two is crushed by the battery module during mounting, but the viscosity of the conductive adhesive before curing is particularly high. Also, as shown in FIG. 2, the thickness L of the conductive adhesive and the reaction force R are in an inverse proportional relationship, and the reaction force increases as the conductive adhesive is crushed.

[0018] Therefore, when trying to reliably insert the positioning pin of the battery module into the hole of the current collector plate, it is necessary to make the positioning pin long and the angle of the lower part (taper angle) steep. However, if the positioning pin is made long, the structure of the battery pack may become complicated and enlarged.

[0019] Therefore, in the battery pack according to the embodiment, for example, as shown in FIG. 3, considering the relationship between the angle of the positioning pin 4 and the force acting on the current collector plate 3, the positioning pin 4 is shaped to satisfy the above formula (1). Thereby, even when using a highly viscous conductive adhesive 2 for joining the battery module 1 and the current collector plate 3, the positioning pin 4 can be smoothly inserted without enlarging the overall structure, and the positioning of the battery module 1 with respect to the current collector plate 3 can be reliably performed.

[0020] (modified version) Here, the lower part of the positioning pin 4 shown in Figure 1 has a linear tapered shape when viewed from the side, but the shape of the lower part of the positioning pin 4 is not limited to this. For example, as shown in Figure 4, a positioning pin 4A with a mortar-shaped lower part may be used.

[0021] The lower part of the positioning pin 4A is formed in a curved shape, and the angle with respect to the surface of the current collector plate 3 is not constant. Specifically, at the lower part of the positioning pin 4A, the angle at the tip side (the angle made by the tangent to the surface of the current collector plate 3) is θ1. Also, at the lower part of the positioning pin 4A, the angle above the tip (the angle made by the tangent to the surface of the current collector plate 3) is θ2.

[0022] The angles θ1 and θ2 are set such that when θ is replaced with θ1 and θ2 respectively, both satisfy the relationship in equation (1) above. Also, the angles θ1 and θ2 are set so that "θ1 < θ2". In other words, the angle θ2 above the tip is set to be larger than the angle θ1 at the tip of the lower part of the positioning pin 4A. To put it another way, the angle of the lower part of the positioning pin 4A is set to gradually increase from the tip upwards.

[0023] When joining the battery module 1 and the current collector plate 3, when the positioning pin 4A is first inserted into the hole 31, the thickness L of the conductive adhesive 2 is still large, and the reaction force R of the conductive adhesive 2 is also small (see Figure 2). That is, because the resistance due to the conductive adhesive 2 is small, the angle θ1 at the lower tip of the positioning pin 4A is made shallow (small). On the other hand, as the positioning pin 4A goes further into the hole 31, the thickness L of the conductive adhesive 2 decreases, and the reaction force R of the conductive adhesive 2 also increases (see Figure 2). That is, because the resistance due to the conductive adhesive 2 increases, the angle θ2 above the lower tip of the positioning pin 4A is made deeper (larger) than the angle θ1.

[0024] In this way, by making the lower part of the positioning pin 4A mortar-shaped, it is difficult for it to move laterally during the initial insertion into the hole 31, but it slides along the edge of the hole 31. Furthermore, during the final insertion into the hole 31, it moves easily laterally and also slides along the edge of the hole 31. Therefore, by making the lower part of the positioning pin 4A mortar-shaped, it becomes possible to further shorten the length of the positioning pin 4A.

[0025] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0026] 1 Battery Module 2. Conductive adhesive 3 Current collector plate 31 Hole 4,4A Positioning pins

Claims

[Claim 1] Battery module and The battery module and the current collector plate are joined via a conductive adhesive, A positioning pin is attached to the lower surface of the battery module and is inserted into a hole provided in the current collector plate to position the battery module relative to the current collector plate. Equipped with, The positioning pin is F ０ A battery pack having a shape that satisfies the following equation (1), where R is the weight of the battery module, R is the reaction force of the conductive adhesive, θ is the angle of the positioning pin, and μ is the coefficient of friction. [Math 1]

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