Secondary batteries
The secondary battery design with a porous body in the case's inner surface prevents electrode damage during electrolyte injection, enabling efficient electrolyte replenishment and cost-effective reuse.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-05
AI Technical Summary
The existing secondary batteries face the risk of electrode body damage during electrolyte injection due to the injection needle piercing the housing portion, which can lead to inefficiencies and increased costs.
A secondary battery design featuring a porous body made of electrolyte-resistant materials in contact with the case's inner surface, with a designated injection port for the needle to penetrate the porous material instead of the electrode body, preventing direct contact.
Prevents electrode body damage during electrolyte injection, allows for efficient electrolyte replenishment, and reduces the need for initial electrolyte content, thereby lowering costs and extending battery life.
Smart Images
Figure 2026092470000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a secondary battery.
Background Art
[0002] Patent Document 1 discloses a secondary battery in which a seal member for additional injection of an electrolytic solution is provided in a part of a battery case, and the electrolytic solution is injected into a housing portion of the battery case by piercing an injection needle through the seal member.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the secondary battery disclosed in Patent Document 1, when injecting the electrolytic solution, there is a risk that the injection needle pierces the electrode body housed in the housing portion of the battery case, and the electrode body may be damaged.
[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a secondary battery capable of suppressing the injection needle from piercing the electrode body when injecting the electrolytic solution.
Means for Solving the Problems
[0006] In order to solve the above problems and achieve the object, a secondary battery according to the present invention is a secondary battery in which an electrode body and an electrolytic solution are housed in a case, and a porous body is provided in contact with an inner surface of a side wall portion of the case, and a portion of the side wall portion in a range contacting the porous body is provided as a liquid injection portion for injecting the electrolytic solution by piercing an injection needle provided in a replenishing liquid injector.
[0007] As a result, in the secondary battery according to the present invention, when the electrolyte is injected by inserting the injection needle of the refilling device into the injection section provided on the side wall of the case, the injection needle penetrates the porous material inside the case, thereby preventing the injection needle from penetrating the electrode body.
[0008] Furthermore, in the above, the porous body may be made of a resin that is resistant to electrolytes, or a rubber that is resistant to electrolytes.
[0009] This makes it possible to suppress the deterioration of porous materials caused by the electrolyte. [Effects of the Invention]
[0010] The secondary battery according to the present invention has the effect of preventing the injection needle from piercing the electrode body when the injection needle of the refillable electrolyte device is inserted into the injection port provided on the side wall of the case and the electrolyte is injected, as the injection needle pierces a porous material inside the case. [Brief explanation of the drawing]
[0011] [Figure 1] Figure 1 is a cross-sectional view showing the schematic configuration of a battery cell according to this embodiment. [Figure 2] Figure 2 is a cross-sectional view showing an example of a deteriorated battery cell according to the embodiment. [Figure 3] Figure 3 is a cross-sectional view showing the state in which electrolyte is replenished to a battery cell according to the embodiment using an electrolyte replenishment device. [Modes for carrying out the invention]
[0012] The following describes an embodiment of the secondary battery according to the present invention. However, the present invention is not limited to this embodiment.
[0013] Figure 1 is a cross-sectional view showing the schematic configuration of a battery cell 1 according to an embodiment. In Figure 1, "height direction" refers to the height direction of the battery cell 1, and "width direction" refers to the width direction of the battery cell 1. In this embodiment, unless otherwise specified, the height direction of the battery cell 1 is simply referred to as "height direction," and the width direction of the battery cell 1 is simply referred to as "width direction."
[0014] As shown in Figure 1, the battery cell 1 according to this embodiment comprises an electrode body 2, a battery cell case 3, porous bodies 4A and 4B, and an electrolyte ES. The electrode body 2 is constructed by stacking, for example, a strip-shaped positive electrode and a strip-shaped negative electrode insulated from each other via a strip-shaped separator, and winding them around an axis. The battery cell case 3 is, for example, a box-shaped housing made of resin, in which the electrode body 2 is housed in a housing space 30 formed inside, and the electrolyte ES is housed so that at least a part of the electrode body 2 is submerged. The battery cell 1 according to this embodiment is a secondary battery constructed by housing the electrode body 2 and the electrolyte ES in the battery cell case 3.
[0015] Furthermore, in the width direction of the battery cell 1, porous bodies 4A and 4B are provided in contact with the inner surfaces 311A and 311B of the side walls 31A and 31B of the battery cell case 3. The porous bodies 4A and 4B are plate-shaped and capable of absorbing the electrolyte ES, and are made of an electrolyte-resistant resin (e.g., polypropylene) or an electrolyte-resistant rubber (e.g., fluororubber (FKM)). This makes it possible to suppress the deterioration of the porous bodies 4A and 4B due to the electrolyte ES. In addition, it is preferable to install the porous bodies 4A and 4B at positions on the inner surfaces 311A and 311B corresponding to the central part of the electrode body 2 in the height direction of the battery cell 1. More preferably, it is preferable to install them so that the centers of the porous bodies 4A and 4B are located at the center of the electrode body 2 in the height direction of the battery cell 1.
[0016] Figure 2 is a cross-sectional view showing an example of a deteriorated state of the battery cell 1 according to the embodiment.
[0017] When the battery cell 1 according to the embodiment deteriorates over time, for example, as shown in FIG. 2, the electrode body 2 expands in the width direction and contacts the porous bodies 4A and 4B, and the electrode body 2 pushes the side wall portions 31A and 31B of the battery cell case 3 outward in the width direction through the porous bodies 4A and 4B. Also, as the battery cell 1 is used over time, the electrolytic solution ES contained in the battery cell case 3 is consumed.
[0018] FIG. 3 is a cross-sectional view showing a state in which the electrolytic solution ES is replenished to the battery cell 1 according to the embodiment by the replenishing liquid injectors 5A and 5B.
[0019] As shown in FIG. 3, the battery cell 1 according to the embodiment can be replenished with the electrolytic solution ES from the outside of the battery cell case 3 by the replenishing liquid injectors 5A and 5B. The replenishing liquid injectors 5A and 5B include containers 6A and 6B made of a hollow plate-like member having rigidity made of metal, the electrolytic solution ES contained in the hollow interiors 60A and 60B of the containers 6A and 6B, and liquid injection needles 7A and 7B for injecting the electrolytic solution ES in the containers 6A and 6B.
[0020] The liquid injection needles 7A and 7B are hollow needles penetrating from the rear end to the front end in the longitudinal direction. It is desirable that the liquid injection needles 7A and 7B be thinner toward the front end side in the longitudinal direction. The material of the liquid injection needles 7A and 7B is preferably resin, but may be metal. The rear ends of the liquid injection needles 7A and 7B in the longitudinal direction protrude inward of the inner side surfaces 611A and 611B of the side wall portions 61A and 61B of the containers 6A and 6B in the width direction and are located in the hollow interiors 60A and 60B. The front ends of the liquid injection needles 7A and 7B in the longitudinal direction protrude outside the outer side surfaces 612A and 612B of the side wall portions 61A and 61B of the containers 6A and 6B in the width direction.
[0021] Furthermore, the liquid injection devices 5A and 5B are provided such that plate-shaped sealing members 8A and 8B are in contact with the outer surfaces 612A and 612B of the side walls 61A and 61B, with the injection needles 7A and 7B passing through them. The sealing members 8A and 8B can be made of materials such as rubber, resin, and adhesives that harden in reaction with the electrolyte ES (water). Alternatively, the sealing members 8A and 8B may be configured such that, for example, an adhesive that hardens upon contact with air is filled into a bag, and when pressed against the battery cell case 3, the bag breaks, exposing the adhesive, which then hardens upon contact with air.
[0022] In the battery cell 1 according to this embodiment, the portion of the side wall portions 31A, 31B of the battery cell case 3 that is in contact with the porous material 4A, 4B (the portion of the side wall portions 31A, 31B that corresponds to the porous material 4A, 4B) is provided as an injection portion. When replenishing electrolyte ES into the battery cell case 3 of a battery cell 1 that has been used over time using the refilling fluid dispensers 5A, 5B, the injection needles 7A, 7B of the refilling fluid dispensers 5A, 5B are inserted into the outer surfaces 312A, 312B of the side wall portions 31A, 31B of the battery cell case 3 that correspond to the injection portion. Then, the refilling fluid dispensers 5A, 5B are pressed against the battery cell 1 so that the outer surfaces 312A, 312B of the side wall portions 31A, 31B of the battery cell case 3 and the sealing members 8A, 8B of the refilling fluid dispensers 5A, 5B are in contact. As a result, after the injection needles 7A and 7B of the refill fluid dispensers 5A and 5B create holes in the side walls 31A and 31B of the battery cell case 3, the area around the injection needles 7A and 7B can be immediately sealed by the sealing members 8A and 8B. Therefore, leakage of electrolyte ES from inside the battery cell case 3 through the holes can be suppressed. It is desirable that the refill fluid dispensers 5A and 5B be restrained in a position where they are pressed against the battery cell 1.
[0023] Also, the liquid injection needles 7A and 7B inserted into the battery cell case 3 are inserted into the porous bodies 4A and 4B. In the battery cell 1 according to the embodiment, the porous bodies 4A and 4B have a function of preventing the electrode body 2 from being damaged when the liquid injection needles 7A and 7B provided in the liquid replenishing devices 5A and 5B pierce the electrode body 2 during replenishment of the electrolytic solution ES into the battery cell case 3. Therefore, the thickness of the porous bodies 4A and 4B in the width direction of the battery cell 1 is set to a thickness through which the liquid injection needles 7A and 7B do not penetrate in order to prevent contact between the electrode body 2 and the liquid injection needles 7A and 7B.
[0024] Also, the porous bodies 4A and 4B also have a function of sending the electrolytic solution ES discharged from the tips of the liquid injection needles 7A and 7B into the accommodation space 30 of the battery cell case 3 through a plurality of voids provided in the porous bodies 4A and 4B. That is, the electrolytic solution ES accommodated in the containers 6A and 6B of the liquid replenishing devices 5A and 5B is discharged from the tip through the hollow interior of the liquid injection needles 7A and 7B by capillary action as indicated by the arrows A1 and B1 in FIG. 3, and is injected (replenished) into the accommodation space 30 through the porous bodies 4A and 4B.
[0025] As described above, in the battery cell 1 according to the embodiment, when injecting the electrolytic solution ES by the liquid replenishing devices 5A and 5B, it is possible to suppress the liquid injection needles 7A and 7B of the liquid replenishing devices 5A and 5B from piercing the electrode body 2 by the porous bodies 4A and 4B provided in the battery cell case 3. Thereby, in the battery cell 1 according to the embodiment, while preventing the electrode body 2 from being damaged by piercing the electrode body 2 with the liquid injection needles 7A and 7B, the electrolytic solution ES can be replenished.
[0026] Generally, battery cells have a small internal space (housing space) in the battery cell case to increase energy volume density, resulting in limited space for electrolyte. Furthermore, the electrolyte contained within the battery cell case is consumed as the battery cell is used. Therefore, if you want to reuse a battery cell that has been used for a while, the amount of electrolyte in the battery cell case may be insufficient, preventing it from performing at its full potential and potentially rendering the used battery cell unusable. Additionally, if you anticipate reusing a used battery cell and include a large amount of electrolyte in the battery cell case from the start, the initial cost of the new battery cell will increase.
[0027] In contrast, the battery cell 1 according to this embodiment has a structure that allows the electrolyte ES to be replenished from the outside into the battery cell case 3 by external fluid injectors 5A and 5B when the battery cell 1 that has been used over time is reused. This makes it possible to effectively utilize the battery cell 1 that has been used over time and to suppress the increase in the initial cost of a new battery cell 1.
[0028] Furthermore, the battery cell 1 according to this embodiment may be provided with a mechanism that can discharge gas accumulated inside the battery cell case 3. This allows for the discharge of gas accumulated inside the battery cell case 3 due to prolonged use, mitigating battery swelling and making it easier to reuse the battery cell 1 after prolonged use. [Explanation of symbols]
[0029] 1 battery cell 2 Electrode body 3 Battery cell case 4A,4B Porous body 5A,5B Refill liquid device 6A, 6B housing 7A,7B Liquid injection needle 8A,8B Sealing member 31A,31B,61A,61B Side wall part 60A,60B hollow interior 311A,311B,611A,611B Inner surface 312A, 312B, 612A, 612B outer surface
Claims
1. A secondary battery in which electrodes and electrolyte are housed in a case, A porous material is provided in contact with the inner surface of the side wall portion of the aforementioned case. The portion of the side wall that comes into contact with the porous body is provided as an injection section for injecting the electrolyte by inserting an injection needle provided in the liquid injection device. A secondary battery characterized by the following features.
2. The secondary battery according to claim 1, characterized in that the porous body is made of a resin having electrolyte resistance or a rubber having electrolyte resistance.