Battery pack

Abstract

The invention relates to a battery pack. The battery pack includes: a battery module; a collector plate that is bonded to the battery module via a conductive adhesive; and a positioning pin which is attached to the lower surface of the battery module, and which positions the battery module with respect to the collector plate by being inserted into a hole provided in the collector plate, when F0 is the weight of the battery module, R is the reaction force of the conductive adhesive, [theta] is the angle of the positioning pin, and [mu] is the coefficient of friction, the positioning pin satisfies the shape of formula (1).

Description

TECHNICAL FIELD

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

[0002] A positioning pin for determining the position of an electric connection terminal is disclosed in Japanese Patent Application Publication No. 2015-028939.

[0003] In the case of, for example, a laminated battery module and a current collecting plate (a cooler), the two are joined using an electrically conductive adhesive. Since, for example, a metal filler is added in this electrically conductive adhesive, the viscosity before curing becomes particularly high. Therefore, for example, in order to smoothly insert a positioning pin into a hole portion provided in a current collecting plate, it is necessary to make the angle of the positioning pin an acute angle. However, for this, it is necessary to make the positioning pin long. As a result, the configuration of the battery pack is sometimes complicated and large-sized. SUMMARY

[0004] The present disclosure provides a battery pack that is capable of smoothly inserting a positioning pin and reliably positioning a battery module with respect to a current collecting plate without complicating and upsizing the configuration.

[0005] The battery pack of the present disclosure is provided with:

[0006] a battery module;

[0007] a current collecting plate joined with the battery module via an electrically conductive adhesive; and

[0008] a positioning pin installed in the lower surface of the battery module, which positions the battery module with respect to the current collecting plate by being inserted into a hole portion provided in the current collecting plate,

[0009] where F0 is the weight of the battery module, R is the reaction force of the electrically conductive adhesive, θ is the angle of the positioning pin, and μ is the coefficient of friction, the positioning pin is a shape that satisfies the following equation (1):

[0010] (Mathematical Equation 1)

[0011] .

[0012] According to the present disclosure, by making the positioning pin a shape that satisfies a predetermined relational expression, even in the case where an electrically conductive adhesive with a high viscosity is used in the joining of a battery module and a current collecting plate, it is possible to smoothly insert the positioning pin without complicating and upsizing the configuration. In addition, it is possible to reliably position the battery module with respect to the current collecting plate. BRIEF DESCRIPTION OF DRAWINGS

[0013] Features, advantages, and technical and industrial significance of exemplary embodiments of the present application will be described below with reference to the accompanying drawings, wherein the same reference numerals denote the same elements throughout the drawings, and

[0014] Figure 1 is a diagram showing a schematic structure of a positioning pin in a battery pack of an embodiment.

[0015] Figure 2 is a graph for explaining a relationship between a thickness L of a conductive adhesive and a reaction force R in a battery pack of an embodiment.

[0016] Figure 3 is a graph for explaining a relationship between an angle of a positioning pin and a force acting on a current collecting plate in a battery pack of an embodiment.

[0017] Figure 4 is a diagram showing a schematic structure of a modification example of a positioning pin in a battery pack of an embodiment. DETAILED DESCRIPTION

[0018] A battery pack of an embodiment of the present disclosure will be described with reference to the drawings. Furthermore, the constituent elements in the following embodiments include elements that can be substituted by those skilled in the art and easily substituted elements or substantially the same elements.

[0019] The battery pack of an embodiment is used, for example, as a battery of a vehicle such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a battery electric vehicle (BEV), and the like.

[0020] As shown in Figure 1 , the battery pack of an embodiment includes a battery module 1, a conductive adhesive 2, a current collecting plate (a cooler) 3, and a positioning pin 4. Furthermore, in Figure 1 , only structures necessary for realizing the battery pack of an embodiment are illustrated, and illustration of other structures is omitted.

[0021] The battery module 1 is constituted by a plurality of battery cells. The battery cell is, for example, a secondary battery such as a lithium ion battery. In addition, in the case where the battery cell is constituted by a lithium ion battery, either a liquid battery or a full solid battery can be used.

[0022] The conductive adhesive 2 is used to join the battery module 1 and the current collecting plate 3. For example, a metal filler is added to the conductive adhesive 2.

[0023] The current collecting plate 3 also functions as a cooler, for example, constituted by a lower case that houses each member of the battery pack. The current collecting plate 3 is joined to the battery module 1 via the electrically conductive adhesive 2. In addition, a hole portion 31 for insertion of the positioning pin 4 is provided in the current collecting plate 3. The diameter of the hole portion 31 is formed to be larger than the diameter of the positioning pin 4.

[0024] The positioning pin 4 is installed to the lower surface of the battery module 1. In addition, the battery module 1 is positioned with respect to the current collecting plate 3 by inserting the positioning pin 4 into the hole portion 31 provided in the current collecting plate 3. In addition, in a case where F0 is set as the self weight of the battery module 1, R is set as the reaction force of the electrically conductive adhesive 2, Θ is set as the angle of the positioning pin 4, and μ is set as the coefficient of friction, the positioning pin 4 has a shape that satisfies the following equation (1).

[0025] (Mathematical equation 2)

[0026]

[0027] Specifically, as shown in Figure 1 , Θ in the above equation (1) indicates the angle of the lower portion (tapered portion) of the positioning pin 4 with respect to the upper surface of the current collecting plate 3. In addition, the lower portion of the positioning pin 4 is, for example, entirely conical, and the angle of the cone is Θ.

[0028] Here, in a case where the battery module is mounted to the current collecting plate, the mounting is performed while the electrically conductive adhesive applied between the two is flattened by the battery module, but the viscosity of the electrically conductive adhesive before curing becomes particularly high. In addition, as shown in Figure 2 , the thickness L of the electrically conductive adhesive is in inverse proportion to the reaction force R, and the more the electrically conductive adhesive is flattened, the more the reaction force increases.

[0029] Therefore, if the positioning pin of the battery module is to be reliably inserted into the hole portion of the current collecting plate, it is necessary to make the positioning pin long and make the angle of the lower portion (tapered angle) steep. However, if the positioning pin is made long, the structure of the battery pack can possibly be complicated and large-sized.

[0030] Therefore, in the battery pack of the embodiment, for example, the relationship between the angle of the positioning pin 4 and the force acting on the current collecting plate 3 as shown in Figure 3 is considered, and the positioning pin 4 is made to have a shape that satisfies the above equation (1). Thereby, even in a case where the electrically conductive adhesive 2 having a high viscosity is used in the joining of the battery module 1 and the current collecting plate 3, it is not necessary to make the entire structure large-sized, and the positioning pin 4 can be smoothly inserted. In addition, the positioning of the battery module 1 with respect to the current collecting plate 3 can be reliably performed.

[0031] Modified example

[0032] Here,Figure 1 The lower portion of the positioning pin 4 is shown as having a straight conical shape when viewed from the side, but the shape of the lower portion of the positioning pin 4 is not limited thereto. For example, as shown in FIG. 6, a positioning pin 4A having a mortar shape can be used. Figure 4

[0033] The lower portion of the positioning pin 4A is formed in a curved surface shape, and the angle with respect to the surface of the current collecting plate 3 is not constant. That is, at the lower portion of the positioning pin 4A, the angle (the angle of the tangent line with respect to the surface of the current collecting plate 3) at the leading end side is θ1. Further, at the lower portion of the positioning pin 4A, the angle (the angle of the tangent line with respect to the surface of the current collecting plate 3) at the position on the upper side from the leading end is θ2.

[0034] The angles θ1, θ2 are set so as to satisfy the above-described relationship of Equation (1) in the case where θ is replaced with θ1 and θ2, respectively. Further, the angles θ1, θ2 are set so as to satisfy "θ1 < θ2". That is, the angle θ2 at the position on the upper side from the leading end is set to be larger than the angle θ1 at the leading end side of the lower portion of the positioning pin 4A. In other words, the angle of the lower portion of the positioning pin 4A is set to gradually increase as it goes from the leading end side toward the upper side.

[0035] In the engagement of the battery module 1 with the current collecting plate 3, at the start of the positioning pin 4A being put into the hole portion 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 FIG. 7). Figure 2 That is, since the resistance generated by the conductive adhesive 2 is small, the angle θ1 at the leading end side of the lower portion of the positioning pin 4A is made shallow (small). On the other hand, as the positioning pin 4A is put into the hole portion 31, the thickness L of the conductive adhesive 2 becomes small, and the reaction force R of the conductive adhesive 2 becomes large (see FIG. 8). Figure 2 That is, since the resistance generated by the conductive adhesive 2 becomes large, the angle θ2 at the position on the upper side from the leading end of the lower portion of the positioning pin 4A is made deeper (larger) than the angle θ1.

[0036] In this way, by making the lower portion of the positioning pin 4A have a mortar shape, at the initial stage of insertion into the hole portion 31, movement along the lateral direction becomes difficult, but movement along the edge portion of the hole portion 31 becomes easy. Further, at the final stage of insertion into the hole portion 31, movement along the lateral direction becomes easy, and movement along the edge portion of the hole portion 31 becomes difficult. Therefore, by making the lower portion of the positioning pin 4A have a mortar shape, it is possible to further shorten the length of the positioning pin 4A.

[0037] ​Further effects, modifications and variations can be apparent from the foregoing as they relate to the principles of the application. Thus, it is intended that the application be limited only by the spirit and scope of the appended claims and their equivalents. Accordingly, various modifications and changes can be made thereto without departing from the spirit and scope of the application, as set forth in the following claims.

Claims

1. A battery pack, wherein, The battery pack includes: Battery module; A current collector, which is bonded to the battery module via a conductive adhesive; as well as A positioning pin is installed on the lower surface of the battery module and is inserted into a hole provided in the current collector to position the battery module relative to the current collector. With F0 set as the weight of the battery module, R set as the reaction force of the conductive adhesive, θ set as the angle of the locating pin, and μ set as the coefficient of friction, the locating pin has a shape that satisfies the following equation (1): 。

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