Secondary battery cell

Abstract

To solve the following problem: in the conventional secondary batteries, the number of secondary batteries to obtain a fixed output voltage becomes large.SOLUTION: A secondary battery cell of the present invention includes: a first electrode body EC1 and a second electrode body EC2; a first current collecting component which has a first external terminal and to which a negative electrode tab of the first electrode body EC1 is connected; a second current collecting component which has a second external terminal 32 and to which a positive electrode tab of the second electrode body EC2 is connected; a third current collecting component to which a positive electrode tab of the first electrode body EC1 and a negative electrode tab of the second electrode body EC2 are connected; a cell case 10 which has a first electrode body housing part that houses the first electrode body EC1 and a second electrode body housing part that houses the second electrode body EC2, the cell case being molded by an insulating resin such that the first current collecting component, the second current collecting component and the third current collecting component are built-in; and a cell lid which brings the cell case 10 into a sealed state so as to cover the first electrode body housing part and the second electrode body housing part.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, battery packs that combine battery cells in series to output a constant output voltage have been 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 cell described in Patent Document 1 relates to a battery cell for storing power, which is assembled into an electric module for assembling a power storage system and has a first surface and a second surface. The battery cell includes at least one male element on one of the first surface and the second surface and at least one female element on the other of the first surface and the second surface. The elements are formed to be fitted together so that the battery cell is attached to another battery cell of the same type. The at least one male element may have at least one electrical connection interface with a positive polarity and the at least one female element may have at least one electrical connection interface with a negative polarity, or vice versa, so that the battery cell is electrically connected to another cell of the same type. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2017-506801 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when trying to reduce the volume of a battery pack that outputs a constant output voltage, it is necessary to reduce the number of battery cells that are combined. However, with the technology described in Patent Document 1, it is not possible to reduce the number of battery cells required to obtain a constant output voltage, making it difficult to reduce the volume of the battery pack.

[0006] The present invention has been made in view of the above circumstances, and has an object to reduce the number of battery cells required to obtain a constant output voltage. [Means for solving the problem]

[0007] One aspect of a secondary battery cell according to the present invention includes a first electrode body and a second electrode body, a first current collecting part having a first external terminal and to which a negative electrode tab of the first electrode body is connected, a second current collecting part having a second external terminal and to which a positive electrode tab of the second electrode body is connected, a third current collecting part to which a positive electrode tab of the first electrode body and a negative electrode tab of the second electrode body are connected, a first electrode body storage section that stores the first electrode body, and a second electrode body storage section that stores the second electrode body, a cell case molded from an insulating resin so that the first current collecting part, the second current collecting part, and the third current collecting part are built in, and a cell lid that seals the cell case so as to cover the first electrode body storage section and the second electrode body storage section. Effect of the Invention

[0008] According to the secondary battery cell of the present invention, it is possible to reduce the number of battery cells required to configure a battery pack that outputs a constant output voltage. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram illustrating an outline of the structure of a secondary battery cell according to the first embodiment. [Diagram 2] 3A to 3C are diagrams illustrating the shape of a current collecting component incorporated in the secondary battery cell according to the first embodiment. [Diagram 3]3A to 3C are diagrams illustrating the shape of a cell case of the secondary battery cell according to the first embodiment. [Figure 4] 2A to 2C are diagrams illustrating the structure of a cell cover and a sealing method for the secondary battery cell according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and repeated explanations are omitted as necessary. In the following description, the direction in which the long sides of the battery cells extend is defined as the width direction X, the direction in which the short sides of the battery cells extend is defined as the thickness direction Y, and the direction perpendicular to the width direction X and stacking direction Y, which is the height of the battery cells, is defined as the height direction Z. In the following description, the left-right direction with respect to the stacking direction Y may be referred to as the left-right direction, and the up-down direction with respect to the height direction Z may be referred to as the up-down direction.

[0011] First embodiment Fig. 1 shows an outline of the structure of a secondary battery cell 1 according to embodiment 1. As shown in Fig. 1, the secondary battery cell 1 according to embodiment 1 accommodates two electrode bodies (for example, a first electrode body EC1 and a second electrode body EC2) aligned along the long side direction of a cell case 10 integrally molded using insulating resin.

[0012] In the secondary battery cell 1 according to the first embodiment, a first current collecting component having a first external terminal exposed on a surface at one end in the long side direction of the cell case 10, a second current collecting component having a second external terminal 32 exposed on a surface at the other end in the long side direction of the cell case 10, and a third current collecting component that ensures electrical conduction between the first electrode body EC1 and the second electrode body EC2 are assembled into the cell case 10. Details of the first current collecting component, the second current collecting component, and the third current collecting component will be described later.

[0013] In the secondary battery cell 1 according to the first embodiment, a first negative electrode current collector terminal 21 having a rod-shaped protrusion is provided on the first current collector, and the rod-shaped portion of the first negative electrode current collector terminal 21 is inserted into a hole formed in the negative electrode tab of the first electrode body EC1 and then crimped to obtain electrical continuity between the first current collector and the negative electrode tab of the first electrode body EC1. In the secondary battery cell 1 according to the first embodiment, a first positive electrode current collector terminal 41 having a rod-shaped protrusion is provided on the third current collector, and the rod-shaped portion of the first positive electrode current collector terminal 41 is inserted into a hole formed in the positive electrode tab of the first electrode body EC1 and then crimped to obtain electrical continuity between the third current collector and the positive electrode tab of the first electrode body EC1.

[0014] In the secondary battery cell 1 according to the first embodiment, a second negative electrode current collector terminal 42 having a rod-shaped protrusion is provided on the third current collector, and the rod-shaped portion of the second negative electrode current collector terminal 42 is inserted into a hole formed in the negative electrode tab of the second electrode body EC2 and then crimped to obtain electrical continuity between the third current collector and the negative electrode tab of the second electrode body EC2. In the secondary battery cell 1 according to the first embodiment, a second positive electrode current collector terminal 31 having a rod-shaped protrusion is provided on the second current collector, and the rod-shaped portion of the second positive electrode current collector terminal 31 is inserted into a hole formed in the positive electrode tab of the second electrode body EC2 and then crimped to obtain electrical continuity between the second current collector and the positive electrode tab of the second electrode body EC2.

[0015] In the first embodiment, by adopting the above-mentioned configuration, the first external terminal is a negative terminal, the second external terminal is a positive terminal, and the first electrode body EC1 and the second electrode body EC2 are connected in series to function as one secondary battery cell that outputs an output voltage. Note that in Fig. 1, the cell lid that seals the cell case 10 is omitted in order to explain the storage state of the electrode bodies.

[0016] 1, a safety valve 33 is provided on the surface where the second external terminal 32 is exposed. This safety valve opens when the internal pressure of the second electrode body storage section in which the second electrode body EC2 is stored reaches or exceeds a set pressure, thereby reducing the internal pressure of the second electrode body storage section and preventing damage to the secondary battery cells.

[0017] Next, a method for manufacturing the secondary battery cell 1 according to the first embodiment will be described with reference to FIGS. 2 to 4. First, FIG. 2 shows a diagram for explaining the shape of the current collecting parts to be assembled in the secondary battery cell according to the first embodiment. As shown in FIG. 2, in the secondary battery cell 1 according to the first embodiment, a first current collecting part 20, a second current collecting part 30, and a third current collecting part 40 are assembled in a cell case 10. The first current collecting part 20 is provided with a first negative current collecting terminal 21, a first external terminal 22, and a safety valve mounting hole 24. The second current collecting part 30 is provided with a second positive current collecting terminal 31, a second external terminal 32, and a safety valve mounting hole 34. The third current collecting part 40 is provided with a first positive current collecting terminal 41 and a second negative current collecting terminal 42. Note that a safety valve is joined to the safety valve mounting hole 24 and the safety valve mounting hole 34 in a later process.

[0018] Here, the third current collecting component 40 has a cylindrical hollow structure, and a thermally conductive material is injected into the hollow structure portion (for example, hollow structure portion 43) in a process after the cell case 10 is formed. By injecting this thermally conductive material into the hollow structure portion 43, the heat dissipation performance of the secondary battery cell 1 can be improved. In particular, since the third current collecting component 40 is a component that connects the first electrode body EC1 and the second electrode body EC2, and heat generated by both the first electrode body EC1 and the second electrode body EC2 is transferred therethrough, improving the heat dissipation performance of this portion is highly effective in suppressing a temperature rise in the secondary battery cell 1.

[0019] Next, FIG. 3 shows a diagram for explaining the shape of the cell case 10 of the secondary battery cell 1 according to the first embodiment. The cell case 10 shown in FIG. 3 is formed by insert molding so that the first current collecting component 20, the second current collecting component 30, and the second current collecting component 30 are built in. Here, the cell case 10 is formed of an insulating resin. Then, the first electrode body storage section 11 and the second electrode body storage section 12 are formed in the formed cell case 10. The first electrode body storage section 11 stores the first electrode body EC1. The second electrode body storage section 12 stores the second electrode body EC2. The first electrode body storage section 11 and the second electrode body storage section 12 are set to a size such that there is no gap with respect to the size of the electrode body portion excluding the tab of the first electrode body EC1. This makes it possible to increase the occupancy rate of the electrode body with respect to the volume of the cell case 10 in the secondary battery cell 1.

[0020] In addition, in the molding of the cell case 10, the parts of the current collecting parts that need to be electrically connected to the electrode body or to things other than the secondary battery cell 1 are exposed so as not to be covered with resin. Specifically, the first external terminal 22 of the first current collecting part 20 and the first negative current collecting terminal 21 to which the negative tab of the first electrode body EC1 is connected are exposed so as not to be covered with resin. The second external terminal 32 of the second current collecting part 30 and the second positive current collecting terminal 31 to which the positive tab of the second electrode body EC2 is connected are exposed so as not to be covered with resin. The first positive current collecting terminal 41 to which the positive tab of the first electrode body EC1 is connected and the second negative current collecting terminal 42 to which the negative tab of the second electrode body is connected are exposed so as not to be covered with resin.

[0021] Next, Fig. 4 shows a diagram for explaining the structure and sealing method of the cell lid 50 of the secondary battery cell 1 according to the first embodiment. In Fig. 4, the first electrode body EC1 and the second electrode body EC2 are housed in the cell case 10. When constructing the secondary battery cell 1, the cell lid 50 is welded to a surface of the cell case 10 having an opening (the surface shown by hatching in Fig. 4) to seal the cell case 10.

[0022] In the manufacturing process of the secondary battery cell 1, the first electrode body EC1 and the second electrode body EC2 are permeated with an electrolyte before being housed in the cell case 10. The electrode bodies are then housed in the cell case 10 with the electrolyte permeated therein, and are then sealed with the cell lid 50. By assembling in this order, it becomes possible to prevent leakage of the secondary battery cell 1.

[0023] As described above, in the secondary battery cell 1 according to the first embodiment, by storing two electrode bodies in series connection in one cell case 10, it is possible to output an output voltage twice that of a battery cell in which only one electrode body is stored in a cell case. In this way, by increasing the output voltage of one secondary battery cell to a voltage that one electrode body can output or higher, it is possible to reduce the number of secondary battery cells used when configuring a battery pack that outputs a certain output voltage. Furthermore, by reducing the number of secondary battery cells that configure one battery pack, it is possible to reduce the volume of the battery pack. Furthermore, by reducing the number of secondary battery cells that configure one battery pack, it is also possible to reduce the cost of configuring one battery pack.

[0024] In addition, in the secondary battery cell 1 according to the first embodiment, the occupancy rate of the electrode body relative to the battery cell volume is increased, so that the storage capacity of one battery cell can be increased by a factor of multiples of the number of electrode bodies. As a result, when the secondary battery cell 1 is used, it is possible to halve the number of secondary battery cells when configuring a battery pack with performance equivalent to that of a battery pack configured with battery cells containing only one electrode body per cell.

[0025] In addition, in the secondary battery cell 1 according to the first embodiment, the cell case 10 and the cell lid 50, both made of resin, are welded together to form a sealed structure for the cell case 10. However, since a welding process that generates dust such as sputter is not used, no treatment is required to prevent foreign matter from entering the first electrode body storage section 11 and the second electrode body storage section 12. Therefore, the secondary battery cell 1 according to the first embodiment can facilitate process management and increase productivity compared to a case in which the cell is sealed using welding. In addition, in the secondary battery cell 1 according to the first embodiment, the probability of foreign matter entering the cell case 10 is low, so that the reliability of the battery cell can be increased.

[0026] 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 present 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 that the above may be reversed. [Explanation of symbols]

[0027] 1. Secondary battery cell 10 Cell Case 11 First electrode housing 12 Second electrode housing 20 First current collecting part 21 First negative electrode current collecting terminal 22 First external terminal 23 Safety valve 24 Safety valve mounting hole 30 Second current collecting part 31 Second positive electrode current collecting terminal 32 Second external terminal 33 Safety valve 34 Safety valve mounting hole 40 Third current collecting part 41 First positive electrode current collecting terminal 42 Second negative electrode current collecting terminal 43 Hollow structure 50 Cell lid EC1 First electrode body EC2 Second electrode body

Claims

1. A first electrode body and a second electrode body; a first current collecting component having a first external terminal and to which a negative electrode tab of the first electrode body is connected; a second current collecting part having a second external terminal and to which a positive electrode tab of the second electrode body is connected; a third current collecting part to which a positive electrode tab of the first electrode body and a negative electrode tab of the second electrode body are connected; a cell case having a first electrode body storage section for storing the first electrode body and a second electrode body storage section for storing the second electrode body, the cell case being molded from an insulating resin so as to incorporate the first current collecting part, the second current collecting part, and the third current collecting part; a cell lid that seals the cell case so as to cover the first electrode housing portion and the second electrode housing portion; A secondary battery cell having a

2. 2. The secondary battery cell according to claim 1, wherein the cell case is formed by insert molding so that a first negative electrode current collecting terminal to which the first external terminal and the negative electrode tab of the first electrode body of the first current collecting component are connected, a second positive electrode current collecting terminal to which the second external terminal and the positive electrode tab of the second electrode body of the second current collecting component are connected, a first positive electrode current collecting terminal to which the positive electrode tab of the first electrode body of the third current collecting component is connected, and a second negative electrode current collecting terminal to which the negative electrode tab of the second electrode body of the third current collecting component is connected are exposed, and the first current collecting component, the second current collecting component, and the third current collecting component are built-in.

3. The secondary battery cell according to claim 1 , wherein the third current collecting component has a cylindrical hollow structure, and a thermally conductive material is injected into the hollow structure.

4. The secondary battery cell according to claim 1 , wherein the first electrode assembly housing portion and the second electrode assembly housing portion are arranged to be aligned in a long side direction of the cell case.

5. The secondary battery cell according to claim 1 , wherein the first electrode body and the second electrode body are wound bodies.

6. The secondary battery cell according to claim 1 , wherein the cell case and the cell lid are joined by welding.

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