Battery case and secondary battery cell

Abstract

To solve the problem in the related art, that the number of battery cells required to obtain a constant output voltage increases.SOLUTION: One aspect of a battery case of the present invention includes a lower case 20 including a first housing part 21 in which a first electrode body 31 is housed and a second housing part 22 in which a second electrode body 34 is housed and which is provided adjacent to the first housing part 21, a first external terminal 10 to which a first electrode terminal 32 of the first electrode body 31 is connected, an intermediate terminal 11 that electrically connects a second electrode terminal 33 of the first electrode body 31 and a first electrode terminal 35 of the second electrode body 34, and the second external terminal 12 to which the second electrode terminal 36 of the second electrode body 34 is connected, and the first external terminal 10, the intermediate terminal 11, and a second external terminal 12 that are disposed such that the intermediate terminal 11 is sandwiched between the first external terminal 10 and the second external terminal 12 on a terminal disposition surface extending in a direction in which the first accommodation part 21 and the second accommodation part 22 are adjacent to each other in a surface of the lower case 20.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to, for example, a battery case in which an electrode assembly is housed and a secondary battery cell. [Background technology]

[0002] In recent years, battery packs that combine battery cells in series to output a constant output voltage have become widely used. In such battery packs, the number of battery cells that make up the battery pack is set according to the target output voltage. Patent Document 1 discloses technology related to the structure of battery cells that can be combined.

[0003] The battery module described in Patent Document 1 is a laminate formed by stacking multiple storage elements, each having foil-shaped positive and negative lead terminals protruding outward from the end, with the lead terminals of different polarities of adjacent storage elements being conductively connected to connecting members formed by extrusion molding of a metal material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-56341 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, secondary batteries have often been used in the form of assembled batteries, in which multiple battery cells are combined to function as a single battery. Furthermore, there are many gaps between the secondary battery cells incorporated into the assembled battery, making it difficult to miniaturize. Patent Document 1 therefore proposes a configuration in which, when constructing a stack of multiple energy storage elements, connecting members are used to connect lead terminals of different polarities of the energy storage elements. However, in the battery module described in Patent Document 1, each energy storage element is not enclosed in a battery case, which poses a problem in that it cannot be applied to cases in which a power unit constructs an assembled battery using secondary battery cells enclosed in a battery case.

[0006] The present invention has been made in view of the above circumstances, and has as its object to reduce the volume of a battery pack including a plurality of secondary battery cells. [Means for solving the problem]

[0007] One aspect of a battery case according to the present invention comprises a lower case having a first storage section in which a first electrode body is stored and a second storage section in which a second electrode body is stored and which is provided adjacent to the first storage section; a first external terminal to which the first electrode terminal of the first electrode body is connected; an intermediate terminal electrically connecting the second electrode terminal of the first electrode body and the first electrode terminal of the second electrode body; and a second external terminal to which the second electrode terminal of the second electrode body is connected, wherein the first external terminal, the intermediate terminal, and the second external terminal are arranged so that the intermediate terminal is sandwiched between the first external terminal and the second external terminal on a terminal arrangement surface of the lower case which extends in the direction in which the first storage section and the second storage section are adjacent to each other.

[0008] One aspect of a battery cell according to the present invention comprises a first electrode body and a second electrode body, a lower case that houses the first electrode body and the second electrode body, a first external terminal to which the first electrode terminal of the first electrode body is connected, an intermediate terminal that electrically connects the second electrode terminal of the first electrode body and the first electrode terminal of the second electrode body, a second external terminal to which the second electrode terminal of the second electrode body is connected, and a lid that covers the lower case, wherein the first external terminal, the intermediate terminal, and the second external terminal are arranged so that the intermediate terminal is sandwiched between the first external terminal and the second external terminal on a terminal arrangement surface of the lower case that extends in a direction in which the first electrode body and the second electrode body are adjacent to each other when the first electrode body and the second electrode body are housed. [Effects of the Invention]

[0009] The battery case and battery cell of the present invention can reduce the number of battery cells required to configure a battery pack that outputs a constant output voltage. [Brief explanation of the drawings]

[0010] [Figure 1] 2 is a schematic diagram illustrating a terminal component of a battery cell according to the first embodiment. FIG. [Figure 2] 2 is a schematic diagram illustrating a lower case and components associated with the lower case of the battery case according to the first embodiment. FIG. [Figure 3] 1 is a schematic diagram illustrating the shape of a battery cell according to a first embodiment. [Figure 4] FIG. 2 is a diagram illustrating a current path of a battery cell according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations are omitted as necessary. In the following description, the direction in which the long sides of a battery cell extend is defined as the width direction X, the direction in which the short sides of the battery cell extend is defined as the thickness direction Z, and the direction perpendicular to the width direction X and the thickness direction Z, which corresponds to the height of the battery cell, is defined as the height direction Y. In the following description, the left-right direction relative to the width direction X may also be referred to as the left-right direction, and the up-down direction relative to the height direction Y. In the examples shown in the following description, a battery cell is assumed to have two electrode bodies arranged side by side in the width direction X of a single battery case.

[0012] Embodiment 1 The battery cell 1 according to the first embodiment has two electrode assemblies housed in a lower case integrally molded from insulating resin, arranged along the long side of the lower case. One of the features of the battery cell 1 according to the first embodiment is the configuration and structure of the electrodes. FIG. 1 shows a schematic diagram illustrating the terminal components of the battery cell according to the first embodiment.

[0013] As shown in Figure 1, the battery cell 1 according to the first embodiment has a first external terminal (e.g., an external positive electrode terminal 10), an intermediate terminal 11, and a second external terminal (e.g., an external negative electrode terminal 12). The first electrode terminal (e.g., a positive electrode) of the first electrode body is connected to the external positive electrode terminal 10. When the first electrode terminal is a positive electrode, the external positive electrode terminal 10 is made of a metal containing aluminum as its main component.

[0014] The intermediate terminal 11 electrically connects the second electrode terminal (e.g., negative electrode) of the first electrode body and the first electrode terminal (e.g., positive electrode) of the second electrode body. Specifically, the intermediate terminal 11 is formed by joining an intermediate negative electrode terminal 11a and an intermediate positive electrode terminal 11b. The intermediate negative electrode terminal 11a, to which the negative electrode of the electrode body is connected, is made of a metal mainly composed of copper, and the intermediate positive electrode terminal 11b, to which the positive electrode of the electrode body is connected, is made of a metal mainly composed of aluminum. The intermediate terminal 11 is formed by integrating the intermediate negative electrode terminal 11a and the intermediate positive electrode terminal 11b using a dissimilar material joining technique.

[0015] A second electrode terminal (e.g., a negative electrode) of the second electrode body is connected to the external negative electrode terminal 12. When the second electrode terminal is a negative electrode, the external negative electrode terminal 12 is formed from a metal containing copper as a main component.

[0016] In the battery cell 1 according to the first embodiment, the external positive terminal 10, intermediate terminal 11, and external negative terminal 12 are insert-molded so as to be embedded in the resin that constitutes the lower case, while being aligned in a straight line in the width direction X of the battery cell 1 in which the electrode bodies are arranged. Figure 2 shows a schematic diagram illustrating the lower case and the components associated with the lower case of the battery case according to the first embodiment.

[0017] As shown in FIG. 2 , the lower case 20 of the battery cell 1 of the first embodiment is formed with an external positive terminal 10, an intermediate terminal 11, and an external negative terminal 12 by insert molding. The lower case 20 also has a first storage section 21 and a second storage section 22. The external positive terminal 10, the intermediate terminal 11, and the external negative terminal 12 are arranged in a terminal arrangement surface of the lower case 20 that extends in the direction in which the first storage section and the second storage section 22 are adjacent to each other, such that the intermediate terminal 11 is sandwiched between the external positive terminal 10 and the external negative terminal 12. Here, the terminal arrangement surface is a surface surrounded by the first and second sides of the lower case 20, where the longest side is the first side and the shortest side is the second side. In the example of FIG. 2 , the first side is a side extending in the width direction X, and the second side is a side extending in the thickness direction Z.

[0018] Furthermore, the resin is molded in the lower case 20 so that the surfaces of the external positive electrode terminal 10 and the external negative electrode terminal 12 that face the outside of the lower case 20 and the back surfaces that face the first storage section 21 and the second storage section 22 are both exposed. Furthermore, the resin is molded in the intermediate terminal 11 so that the surfaces of the intermediate negative electrode terminal 11a and the intermediate positive electrode terminal 11b that face the outside of the lower case 20 and the back surfaces that face the first storage section 21 and the second storage section 22 are both exposed. However, as shown in FIG. 2 , the lower case 20 is molded so that the portion of the intermediate terminal 11 where the intermediate negative electrode terminal 11a and the intermediate positive electrode terminal 11b are joined is covered with resin.

[0019] By covering the joint surfaces of the intermediate negative electrode terminal 11a and the intermediate positive electrode terminal 11b with resin in this manner, the joint surfaces are not exposed to air, and therefore corrosion of the joint surfaces can be prevented.

[0020] In the battery cell 1 according to the first embodiment, an insulating cover 40 is provided at a position corresponding to the intermediate terminal 11. At least the surface of the insulating cover 40 is made of an insulating material. For example, the insulating cover 40 is made of an insulating material such as aluminum nitride. The insulating cover 40 is shaped so that it contacts the intermediate negative electrode terminal 11a and the intermediate positive electrode terminal 11b that are exposed to the outside after the resin is formed. Here, the insulating cover 40 preferably has a higher thermal conductivity than the resin that constitutes the lower case 20. By forming the insulating cover 40 from a material with such high thermal conductivity, the insulating cover 40 can function as a heat dissipation component that promotes the release of heat generated in the battery cell 1. In other words, by using a material with high insulating properties and heat dissipation properties for the insulating cover 40, it is possible to provide the insulating cover 40 with both insulating and heat dissipation functions.

[0021] As shown in FIG. 2 , the first storage section 21 stores a first electrode body 31, and the second storage section 22 stores a second electrode body 34. In this stored state, the positive electrode tab 32 of the first electrode body 31 is joined to the external positive electrode terminal 10. The negative electrode tab 33 of the first electrode body 31 is joined to the intermediate negative electrode terminal 11a. In addition, in the stored state, the positive electrode tab 35 of the second electrode body 34 is joined to the intermediate positive electrode terminal 11b. The negative electrode tab 36 of the second electrode body 34 is joined to the external negative electrode terminal 12.

[0022] 2, a smoke exhaust port 23 is formed in the first storage section 21, and a smoke exhaust port 24 is formed in the second storage section 22. The smoke exhaust ports 23, 24 are provided on the surface (hereinafter referred to as the case bottom) opposite the surface on which the external positive terminal 10, intermediate terminal 11, and external negative terminal 12 are provided. The smoke exhaust ports 23, 24 are T-shaped and have a height such that the surface with the larger upper area contacts the surface (hereinafter referred to as the electrode body bottom) opposite the surface on which the electrode tabs of the first electrode body 31 and the second electrode body 34 are formed. With these smoke exhaust ports 23, 24, the bottom surface of the electrode body in a stored state in the battery cell 1 is supported by the member on which the smoke exhaust port is formed.

[0023] The smoke exhaust ports 23, 24 are provided with holes that penetrate through members formed in a shape that supports the first electrode body 31 and the second electrode body 34. The holes are provided with relief valves (not shown) that release gas from the storage compartment to the outside if the internal pressure of each compartment increases. The battery cell 1 is designed with these relief valves to prevent the internal pressure of the storage compartment from increasing above a certain level.

[0024] Next, Fig. 3 is a schematic diagram illustrating the shape of the battery cell according to the first embodiment. Fig. 3 is a diagram illustrating a state in which the first electrode body 31 and the second electrode body 34 described in Fig. 2 are housed in their respective storage compartments, and the lid 50 is placed over the lower case 20 to which the insulating cover 40 is attached. In the battery cell 1 according to the first embodiment, the first electrode body 31 and the second electrode body 34 are housed in their respective storage compartments, and then an electrolyte is poured into each storage compartment to impregnate each electrode body with the electrolyte, and the lid 50 is then attached to the lower case 20 so as to cover the first storage compartment 21 and the second storage compartment 22.

[0025] 3 shows an example in which one lid 50 is provided for two storage sections, but a separate lid 50 may be prepared for each storage section. By providing a lid for each storage section in this way, it is possible to obtain effects such as making it easier to weld the lids and making it possible to adjust the pressure applied to each electrode body by changing the shape of the lid in accordance with variations in each electrode body.

[0026] Next, the current path in the battery cell 1 manufactured in this manner will be described. FIG. 4 is a diagram illustrating the current path in the battery cell according to the first embodiment. As shown in FIG. 4, in the battery cell 1 according to the first embodiment, the external positive terminal 10, intermediate terminal 11, and external negative terminal 12 are arranged in a straight line on the same surface. Therefore, the current path passes through a portion of the electrode body that is close to the terminal arrangement surface, and is formed as a route with minimal meandering relative to the terminal arrangement surface. This enables the battery cell 1 according to the first embodiment to have a reduced resistance value as a battery.

[0027] As explained above, in the battery cell 1 according to the first embodiment, two electrode bodies are housed in one case by using the intermediate terminal 11. By housing two electrode bodies in one battery cell in this manner while connected by an intermediate terminal insert-molded into the lower case 20, it is possible to reduce the parts and gaps connecting the cells and to output the output equivalent to that of two cells. Furthermore, by using such battery cells to construct a battery pack, it is possible to reduce the volume of the battery pack.

[0028] Furthermore, in the battery cell 1, the portion of the intermediate terminal 11 where different components are joined is covered with resin, which makes it possible to prevent corrosion of the joint surface between the intermediate negative electrode terminal 11a and the intermediate positive electrode terminal 11b. Furthermore, in the battery cell 1, the insulating cover 40 has high insulating properties, which improves safety. Furthermore, the insulating cover 40 has high thermal conductivity, which improves the heat dissipation performance of the battery cell 1.

[0029] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the invention. For example, in the above description, the first external terminal is the negative terminal and the second body terminal is the positive terminal, but it is easily conceivable to reverse this. [Explanation of symbols]

[0030] 1 battery cell 10 External positive terminal 11 Intermediate terminal 11a Intermediate negative terminal 11b Intermediate positive terminal 12 External negative terminal 20 Lower Case 21 First storage compartment 22 Second storage area 23 Smoke exhaust vent 24 Smoke exhaust vent 31 First electrode body 32 Positive electrode tab 33 Negative electrode tab 34 Second electrode body 35 Positive electrode tab 36 Negative electrode tab 40 Insulating cover 50 lids

Claims

1. a lower case including a first storage section in which a first electrode body is stored and a second storage section in which a second electrode body is stored and which is provided adjacent to the first storage section; a first external terminal to which a first electrode terminal of the first electrode body is connected; an intermediate terminal that electrically connects the second electrode terminal of the first electrode body and the first electrode terminal of the second electrode body; a second external terminal to which the second electrode terminal of the second electrode body is connected, The first external terminal, the intermediate terminal, and the second external terminal are arranged on a terminal arrangement surface of the lower case that extends in a direction in which the first storage section and the second storage section are adjacent to each other, so that the intermediate terminal is sandwiched between the first external terminal and the second external terminal.

2. 2. The battery case according to claim 1, wherein at least a surface of the intermediate terminal is covered with an insulating cover made of an insulating material.

3. 3. The battery case according to claim 2, wherein the insulating cover has a thermal conductivity higher than that of the material constituting the lower case.

4. 2. The battery case according to claim 1, wherein the terminal arrangement surface is a surface surrounded by the first side and the second side of the lower case, where the longest side of the lower case is defined as a first side and the shortest side is defined as a second side.

5. The battery case according to claim 1 , wherein the intermediate terminal is fixed in place by insert molding with the resin that forms the first housing portion and the second housing portion.

6. The battery case according to claim 5 , wherein the intermediate terminal has a structure in which different members are joined together, and the joined portion is covered with the resin.

7. 2. The battery case according to claim 1, wherein the first external terminal and the second external terminal are fixed in a state where they are insert-molded with a resin that forms the first storage portion and the second storage portion.

8. a first electrode body and a second electrode body; a lower case that houses the first electrode body and the second electrode body; a first external terminal to which a first electrode terminal of the first electrode body is connected; an intermediate terminal that electrically connects the second electrode terminal of the first electrode body and the first electrode terminal of the second electrode body; a second external terminal to which a second electrode terminal of the second electrode body is connected; a lid for covering the lower case, The first external terminal, the intermediate terminal, and the second external terminal are arranged on a terminal arrangement surface of the lower case that extends in a direction in which the first electrode body and the second electrode body are adjacent to each other when the first electrode body and the second electrode body are stored, so that the intermediate terminal is sandwiched between the first external terminal and the second external terminal.

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