Secondary battery

Abstract

The utility model relates to a secondary battery which houses an electrode body and an electrolyte in a case, a porous body is provided on the inner side of a side wall portion of the case, the porous body is in contact with the inner side, the portion of the side wall portion which is in contact with the porous body serves as a liquid injection portion, and the liquid injection portion is used to inject the electrolyte into the case by inserting a liquid injection needle of a liquid injection device into the liquid injection portion.

Description

Technical Field

[0001] This utility model relates to a secondary battery. Background Technology

[0002] Japanese Patent No. 6830106 discloses a secondary battery in which a sealing member for adding electrolyte is provided in a part of the battery casing, and electrolyte is injected into the receiving part of the battery casing by injecting an injection needle through the sealing member.

[0003] In the secondary battery disclosed in Japanese Patent No. 6830106, when injecting electrolyte, the injection needle may pierce the electrode body housed in the receiving part of the battery casing and damage the electrode body. Utility Model Content

[0004] This invention addresses the aforementioned technical problems and aims to provide a secondary battery capable of preventing the injection needle from piercing the electrode body during electrolyte injection.

[0005] To solve the above-mentioned technical problems, this utility model provides a secondary battery that houses an electrode body and an electrolyte inside a housing. A porous material is provided on the inner side of the side wall of the housing, and the porous material is in contact with the inner side. The part of the side wall that is in contact with the porous material serves as an injection part. The injection part is used to inject the electrolyte into the housing by inserting the injection needle of a supplementary injector into the injection part.

[0006] Therefore, when the electrolyte is injected into the secondary battery of this invention by inserting the injection needle of the supplementary injector into the injection part located on the side wall of the casing, the injection needle can be inserted into the porous material inside the casing to prevent the injection needle from penetrating the electrode body.

[0007] In this invention, the porous body can be made of a resin or a rubber that is resistant to electrolytes.

[0008] This can suppress the deterioration of porous materials caused by electrolyte.

[0009] The secondary battery of this invention has the following effect: when injecting electrolyte into the injection part of the injection device located on the side wall of the casing by inserting the injection needle of the supplementary injection device, the injection needle can be inserted into the porous body inside the casing to prevent the injection needle from penetrating the electrode body. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view showing the general structure of the battery cell involved in the embodiment.

[0011] Figure 2 This is a cross-sectional view illustrating an example of the deterioration state of a battery cell in an embodiment.

[0012] Figure 3 This is a cross-sectional view showing the state of replenishing electrolyte to the battery cell of the embodiment using a replenishment injector. Detailed Implementation

[0013] The following describes the embodiments of the secondary battery of this utility model. However, this utility model is not limited to these embodiments.

[0014] Figure 1 This is a cross-sectional view showing the general structure of the battery cell 1 according to the embodiment. Additionally, Figure 1 The "height direction" in the text refers to the height direction of battery cell 1. Figure 1 In this embodiment, "width direction" refers to the width direction of battery cell 1. Additionally, unless otherwise specified in this embodiment, the height direction of battery cell 1 is simply referred to as "height direction," and the width direction of battery cell 1 is simply referred to as "width direction."

[0015] like Figure 1 As shown, the battery cell 1 according to the embodiment includes an electrode body 2, a battery cell housing 3, porous materials 4A and 4B, and an electrolyte ES. The electrode body 2 is configured, for example, by stacking strip-shaped positive and negative electrodes insulated from each other by strip-shaped separators, and winding them around an axis. The battery cell housing 3 is, for example, a box-shaped frame made of resin, which houses the electrode body 2 in an internal receiving space 30 and contains the electrolyte ES such that at least a portion of the electrode body 2 is submerged. Furthermore, the battery cell 1 according to the embodiment is a secondary battery constructed by housing the electrode body 2 and the electrolyte ES within the battery cell housing 3.

[0016] Furthermore, in the width direction of the battery cell 1, porous materials 4A and 4B are provided on the inner surfaces 311A ​​and 311B of the sidewall portions 31A and 311B of the battery cell housing 3, and the porous materials 4A and 4B are in contact with the inner surfaces 311A ​​and 311B. The porous materials 4A and 4B are plate-shaped and can absorb electrolyte ES, and are made of a resin (e.g., polypropylene) or a rubber (e.g., fluororubber (FKM)) that is resistant to electrolyte. This can suppress the deterioration of the porous materials 4A and 4B caused by electrolyte ES. In addition, it is preferable that the porous materials 4A and 4B are provided in the height direction of the battery cell 1 at a position corresponding to the center of the inner surfaces 311A ​​and 311B. More preferably, they are provided in the height direction of the battery cell 1 such that the center of the porous materials 4A and 4B is located at the center of the electrode body 2.

[0017] Figure 2 This is a cross-sectional view showing an example of the deterioration state of the battery cell 1 according to the embodiment.

[0018] When the battery cell 1 of the embodiment deteriorates due to prolonged use, for example... Figure 2 As shown, the electrode body 2 expands in the width direction to contact the porous bodies 4A and 4B, and the electrode body 2 presses the sidewall portions 31A and 31B of the battery cell housing 3 outward in the width direction via the porous bodies 4A and 4B. Furthermore, as the battery cell 1 is used over time, the electrolyte ES contained in the battery cell housing 3 is gradually consumed.

[0019] Figure 3 This is a cross-sectional view showing the state of replenishing electrolyte ES to the battery cell 1 according to the embodiment using replenishment injectors 5A and 5B.

[0020] like Figure 3 As shown, the battery cell 1 of the embodiment can be replenished with electrolyte ES from outside the battery cell housing 3 by replenishment injectors 5A and 5B. The replenishment injectors 5A and 5B have: receiving containers 6A and 6B made of rigid, hollow, plate-like members made of metal; electrolyte ES contained in the hollow interiors 60A and 60B of the receiving containers 6A and 6B; and injection needles 7A and 7B for injecting electrolyte ES into the receiving containers 6A and 6B.

[0021] Injection needles 7A and 7B are hollow needles extending from the rear end to the top end in the length direction. Furthermore, injection needles 7A and 7B are preferably tapered towards the top end in the length direction. The material of injection needles 7A and 7B is preferably resin, but metal is also acceptable. The rear end of injection needles 7A and 7B in the length direction protrudes inward in the width direction from the inner surfaces 611A and 611B of the sidewalls of the receiving containers 6A and 6B, and is located within the hollow interior 60A and 60B. The top end of injection needles 7A and 7B in the length direction protrudes outward in the width direction from the outer surfaces 612A and 612B of the sidewalls of the receiving containers 6A and 6B.

[0022] Furthermore, the replenishing injectors 5A and 5B are configured to contact the plate-shaped sealing components 8A and 8B while the injection needles 7A and 7B penetrate the outer surfaces 612A and 612B of the sidewall portions 61A and 61B. The sealing components 8A and 8B can be made of materials such as rubber, resin, and adhesives that cure upon reaction with the electrolyte ES (water). Alternatively, the sealing components 8A and 8B can be configured such that the bag is filled with an adhesive that solidifies upon contact with air; when the bag ruptures upon contact with the battery cell housing 3, the adhesive is exposed and cures upon contact with air.

[0023] In the battery cell 1 of the embodiment, the portion of the sidewall portions 31A and 31B of the battery cell housing 3 that contacts the porous materials 4A and 4B (the portion of the sidewall portions 31A and 31B corresponding to the porous materials 4A and 4B) serves as the electrolyte injection portion. When replenishing electrolyte ES into the battery cell housing 3 of the battery cell 1 used over time by the replenishing injectors 5A and 5B, the injection needles 7A and 7B of the replenishing injectors 5A and 5B are inserted into the outer surfaces 312A and 312B of the sidewall portions 31A and 31B of the battery cell housing 3 at positions corresponding to the electrolyte injection portions. Then, the replenishing injectors 5A and 5B are pressed against the battery cell 1 so that the outer surfaces 312A and 312B of the sidewall portions 31A and 31B of the battery cell housing 3 come into contact with the sealing members 8A and 8B of the replenishing injectors 5A and 5B. Therefore, after holes are made in the side walls 31A and 31B of the battery cell housing 3 using the injection needles 7A and 7B of the replenishing injectors 5A and 5B, the area around the injection needles 7A and 7B can be immediately sealed with sealing members 8A and 8B. This prevents the electrolyte ES inside the battery cell housing 3 from leaking out through the holes. Furthermore, it is preferable that the replenishing injectors 5A and 5B are restrained while being pressed against the battery cell 1.

[0024] Furthermore, the injection needles 7A and 7B, which pierce the battery cell housing 3, penetrate the porous materials 4A and 4B. In the battery cell 1 of this embodiment, the porous materials 4A and 4B have the following function: to prevent the injection needles 7A and 7B of the electrolyte injectors 5A and 5B from piercing the electrode body 2 and causing damage to the electrode body 2 when replenishing electrolyte ES into the battery cell housing 3. Therefore, in order to prevent the electrode body 2 from contacting the injection needles 7A and 7B, the thickness of the porous materials 4A and 4B in the width direction of the battery cell 1 is set to a thickness that the injection needles 7A and 7B cannot penetrate.

[0025] In addition, the porous bodies 4A and 4B also have the following function: the electrolyte ES discharged from the tips of the injection needles 7A and 7B is transported into the battery cell housing 3 through multiple pores provided in the porous bodies 4A and 4B. That is, the electrolyte ES replenished in the receiving containers 6A and 6B of the injection devices 5A and 5B is transported into the battery cell housing 3. Figure 3 As shown by the middle arrows A1 and B1, the liquid is discharged from the top through the hollow interior of the injection needles 7A and 7B using the capillary effect, and injected into the receiving space 30 through the porous bodies 4A and 4B (supplement).

[0026] As described above, when the battery cell 1 of this embodiment injects electrolyte ES using the replenishing injectors 5A and 5B, the porous bodies 4A and 4B disposed within the battery cell housing 3 can be used to prevent the injection needles 7A and 7B of the replenishing injectors 5A and 5B from piercing the electrode body 2. Therefore, the battery cell 1 of this embodiment can replenish electrolyte ES while preventing the injection needles 7A and 7B from piercing the electrode body 2 and damaging it.

[0027] Generally, to increase energy volume density, the internal space (accommodation space) of the battery cell casing is relatively small, and the space for containing the electrolyte is also small. Furthermore, the electrolyte contained within the battery cell casing is consumed during battery cell use. Therefore, when reusing a battery cell that has been used for a period of time, there is a concern that insufficient electrolyte in the battery cell casing may prevent the battery from performing at its original capacity, thus hindering the effective utilization of the used battery cell. On the other hand, if the reuse of a used battery cell were to involve containing a larger amount of electrolyte in its new state, the initial cost of the new battery cell would increase.

[0028] In contrast, the battery cell 1 of the embodiment has a structure that allows electrolyte ES to be replenished from the outside into the battery cell housing 3 via replenishment injectors 5A and 5B when the battery cell 1 has been used for a period of time and is reused. This enables efficient utilization of the battery cell 1 that has been used for a period of time, while suppressing the increase in the initial cost of new battery cells 1.

[0029] Furthermore, in the battery cell 1 of the embodiment, a mechanism for venting accumulated gas can be provided inside the battery cell housing 3. This allows the gas accumulated inside the battery cell housing 3 over time to be released, alleviating battery swelling and making it easier to reuse the battery cell 1 after prolonged use.

Claims

1. A secondary battery, comprising an electrode body and an electrolyte housed within a casing, characterized in that, A porous material is provided on the inner surface of the side wall of the shell, and the porous material is in contact with the inner surface. The portion of the sidewall that contacts the porous material serves as the injection section, which is used to inject the electrolyte into the housing by inserting the injection needle of the supplementary injector into the injection section.

2. The secondary battery according to claim 1, characterized in that, The porous body is composed of a resin or a rubber that is resistant to electrolytes.

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