Electrode stack and battery
By incorporating a thin film region at the ends and a thicker film region in the fixing member, the peeling issue is mitigated, ensuring the electrode laminate's stability and reducing short circuit risks.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2023-09-15
- Publication Date
- 2026-07-07
AI Technical Summary
The fixing member containing a curable resin in electrode laminates tends to peel off, compromising its ability to fix the layers effectively.
The fixing member is designed with a thin film region at its ends and a thicker film region elsewhere, with the thin film region's thickness being 50% or less of the thicker region's thickness, to alleviate stress from curing shrinkage and prevent peeling.
This design significantly reduces the peeling of the fixing member, enhancing the stability of the electrode laminate and reducing the risk of short circuits and electrode misalignment.
Smart Images
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Abstract
Description
Technical Field
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[0001] The present disclosure relates to an electrode laminate and a battery.
Background Art
[0002] In secondary batteries such as lithium ion batteries, an electrode laminate may be used. In such an electrode laminate, in order to prevent displacement of each layer, etc., a technique has been developed in which a fixing member containing a curable resin is provided on the side surface portion of the electrode laminate.
[0003] For example, Patent Document 1 discloses a method for manufacturing an all-solid-state battery including a flat laminate-type electrode body (electrode laminate), an exterior body made of a laminate film that houses the laminate-type electrode body, and a resin-made protective member (fixing member) formed on the side surface of the laminate-type electrode body.
[0004] Also, Patent Document 1 discloses using a resin material having photocurability or thermocurability as the protective member.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] The fixing member containing a curable resin may peel off from the electrode laminate, and as a result, there is a problem that the function as a fixing member cannot be sufficiently exhibited.
[0007] An object of the present disclosure is to provide an electrode laminate in which a fixing member disposed on the side surface portion is difficult to peel off, and a battery having such an electrode laminate.
Means for Solving the Problems
[0008] The Disclosing Party has found that the above-mentioned problems can be solved by the following means. <Aspect 1> An electrode laminate in which a fixing member containing a curable resin is disposed on at least one side surface, The aforementioned fixing member has a thin film region and a thick film region, The thin film region is formed at at least one end of the fixing member, including the end, and the thick film region is formed in the portion other than the thin film region. Electrode stack. <Aspect 2> The thickness of the fixing member is thinnest at the end, The thickness of the end portion is 50% or less of the thickness of the thick film region. The electrode laminate according to embodiment 1. <Aspect 3> The electrode laminate according to embodiment 1 or 2, wherein the length of the thin film region is 1 mm or more. <Aspect 4> The electrode laminate according to any one of embodiments 1 to 3, wherein the thickness of the thick film region is 50 μm or more and 5 mm or less. <Aspect 5> An electrode laminate according to any one of embodiments 1 to 4, and Laminate film sealing the electrode stack A battery containing a battery. [Effects of the Invention]
[0009] According to this disclosure, it is possible to provide an electrode laminate in which the fixing members arranged on the side surface are less likely to peel off, and a battery having such an electrode laminate. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a schematic diagram showing an example of the electrode stack of this disclosure. [Figure 2] Figure 2 is an enlarged view of the area near the thin film region of the fixing member in the electrode stack of this disclosure. [Figure 3]FIG. 3 is a schematic plan view showing an example of the battery of the present disclosure. [Figure 4] FIG. 4 is a schematic view of an electrode laminate according to the prior art.
Mode for Carrying Out the Invention
[0011] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the disclosure.
[0012] 《Electrode Laminate》 In the electrode laminate of the present disclosure, a fixing member containing a curable resin is disposed on at least one side surface portion. The fixing member has a thin film region and a thick film region. The thin film region is formed at at least one end portion including the end of the fixing member, and the thick film region is formed in a portion other than the thin film region.
[0013] The present inventors considered that one of the causes of the peeling of the fixing member containing the curable resin from the electrode laminate is due to the stress generated along with the curing shrinkage of the curable resin.
[0014] Regarding this, the present inventors have found that by forming a thin film region having a thickness of the fixing member thinner than that of the thick film region at at least one end portion including the end of the fixing member, it is possible to suppress the peeling of the fixing member containing the curable resin from the electrode laminate. Although not intending to be bound by any theory, it is considered that this is because by providing the fixing member with the above-described difference in thickness, the stress generated along with the curing shrinkage of the curable resin can be relaxed.
[0015] Hereinafter, the electrode laminate 12 of the present disclosure will be described with reference to FIG. 1. Note that the dimensional relationships (length, width, thickness, etc.) in FIG. 1 and other drawings do not reflect the actual dimensional relationships. FIG. 1 is a schematic diagram showing an example of the electrode laminate 12 of the present disclosure. The shape of the electrode laminate 12 is not particularly limited. For example, as shown in FIG. 1, it has a top surface portion, a bottom surface portion facing the top surface portion, and four side surface portions connecting the top surface portion and the bottom surface portion. Further, in the electrode laminate 12 of the present disclosure, a fixing member 11 containing a curable resin is disposed on at least one side surface portion.
[0016] In the present disclosure, the "electrode laminate" means a laminate constituting one or more unit cells. Here, this "unit cell" may be composed of a laminate of a positive electrode current collector layer, a positive electrode active material layer, an electrolyte layer (separator layer), a negative electrode active material layer, and a negative electrode current collector layer.
[0017] The fixing member 11 may be disposed on two or more side surface portions of the electrode laminate 12. In particular, fixing members may be disposed on a pair of opposing side surface portions of the electrode laminate 12, and other members such as terminals may be disposed on the remaining pair of side surface portions. In this case, the effect of preventing the displacement of the electrodes by the fixing member 11 is improved, and it becomes easier to prevent short circuits due to the intrusion of conductive foreign matter and damage due to external impacts.
[0018] The curable resin is not particularly limited, and examples thereof include photocurable resins such as ultraviolet curable resins and electron beam curable resins, and thermosetting resins. Further, the curable resin may be a radical polymerizable resin, a cationic polymerizable resin, or a combination thereof.
[0019] As shown in Figure 1(a), in the electrode laminate 12 of this disclosure, the fixing member 11 has a thin film region 11a and a thick film region 11b. The thin film region 11a is formed at least one end of the fixing member 11, including the end 11c, and the thick film region 11b is formed in the portion other than the thin film region 11a. With this configuration, as described above, it is possible to alleviate the stress generated due to the curing shrinkage of the curable resin, and as a result, it is thought that the peeling of the fixing member 11 from the electrode laminate 12 can be suppressed.
[0020] Furthermore, the "thin film region" refers to a region where the thickness of the fixing member is relatively thinner than that of the thick film region, while the "thick film region" refers to a region where the thickness of the fixing member is relatively thicker than that of the thin film region.
[0021] As shown in Figure 1(b), thin film regions 11a may be formed on both sides of the fixing member 11. This configuration improves the effect of relieving stress generated due to the curing shrinkage of the curable resin, and more effectively suppresses the delamination of the fixing member 11 from the electrode laminate 12.
[0022] Figure 2 is a schematic plan view of the electrode stack 12 of this disclosure, viewed from the stacking direction, with an enlarged view of the area near the thin film region 11a of the fixing member 11. As shown in Figure 2(a), the fixing member 11 may have a shape in which the thickness gradually decreases toward the end 11c in the thin film region 11a. Also, as shown in Figure 2(b), the fixing member 11 may have a shape with a step in the thin film region 11a such that the thickness of the end 11c is minimized.
[0023] One method for arranging the fixing member 11 in this manner is to apply the UV-curable resin to the side surface of the electrode stack using a dispenser, by adjusting the amount of discharged resin at the end, thereby reducing the thickness of the end surface, including the end, on the side surface of the electrode stack, and increasing the thickness of the other parts.
[0024] The thickness of the thin film region 11 is thinnest at the end 11c, and the thickness T1 of the end 11c may be 50% or less of the thickness T2 of the thick film region 11b. The thickness of the end 11c of the thin film region may be greater than 0 μm, 25 μm or more, 50 μm or more, or 100 μm or more, and may be 2.5 mm or less, 2.0 mm or less, 1.5 mm or less, or 1.0 mm or less. Furthermore, this thickness T1 may be 0.4 mm.
[0025] The length L of the thin film region 11a may be 1 mm or more. This length L may be 2 mm or more, 3 mm or more, or 4 mm or more, and may be 10 mm or less, 8 mm or less, or 6 mm or less. Furthermore, this length L may be 5 mm.
[0026] The thickness T2 of the thick film region 11b may be 50 μm or more and 5 mm or less. This thickness T2 may be 100 μm or more, 500 μm or more, or 800 μm or more, and may be 4 mm or less, 3 mm or less, or 2 mm or less. Alternatively, this thickness T2 may be 1 mm. A thicker thickness T2 makes it easier to prevent electrode misalignment and short circuits due to the inclusion of conductive foreign matter. A thinner thickness T2 can reduce the loss of energy density in the battery and make it easier to suppress stress generated due to curing shrinkage of the curable resin. Note that this thickness T2 may be the average thickness of the entire fixing member 11.
[0027] One method for adjusting the thickness T2 of the thick film region 11b is to adjust the viscosity of the curable resin applied to form the fixing member 11.
[0028] The length of the fixing member 11 in the stacking direction of the electrode stack 12 may be less than the thickness of the electrode stack 12.
[0029] "battery" The battery 10 of this disclosure will be described below with reference to Figure 3. Figure 3 is a schematic plan view showing an example of the battery 10 of this disclosure, viewed from the stacking direction of the electrode stack 12.
[0030] As shown in Figure 3, the battery 10 of the present disclosure has an electrode stack 12 of the present disclosure and a laminate film 13 that seals the electrode stack 12.
[0031] <Electrode Laminate> The electrode stack 12 functions as a power generation element of the battery. For details regarding the electrode stack 12, please refer to the above description of the electrode stack in this disclosure.
[0032] <Laminating film> The laminate film 13 seals the electrode laminate 12 by winding it around it as desired. The laminate film 13 may have a welding layer and a metal layer, and the electrode laminate 12 can be sealed by welding the welding layers together and / or welding the welding layers to the current collector terminals 15 described later. The material of the welding layer may be, for example, a resin that can be welded by heat.
[0033] The battery 10 of this disclosure may further have current collector terminals 15 electrically connected to the current collector foil 14 of the electrode stack 12, as shown in Figure 3, and a laminate film 13 may wrap around the electrode stack 12 and the current collector terminals 15 to seal the electrode stack 12 together with the current collector terminals 15.
[0034] <Current collector foil> The current collector foil 14 may extend from the side surface of the electrode laminate 12 where the fixing member 11 is not located. The current collector foil 14 may be a bundle of portions of the positive electrode current collector in the electrode laminate 12 where other layers are not laminated, and a bundle of portions of the negative electrode current collector in the electrode laminate 12 where other layers are not laminated.
[0035] <Collector terminal> The current collector terminal 15 may be electrically connected to the current collector foil 14. The material of the current collector terminal 15 is not particularly limited as long as it is a material that has a current collecting function, and for example, it can be the same metal material as the positive electrode current collector and the negative electrode current collector.
[0036] The method for joining the current collector terminal and the current collector foil is not particularly limited, but an example of joining them using ultrasound is provided.
[0037] There are no particular limitations on the method for welding the laminate film to the current collection terminal, but heat welding is one example.
[0038] The battery in this disclosure may be a liquid-based battery or a solid-state battery. In this disclosure, "solid-state battery" means a battery that uses at least a solid electrolyte as its electrolyte, and therefore a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as its electrolyte. Furthermore, the solid-state battery in this disclosure may be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as its electrolyte.
[0039] The battery in this disclosure may be a lithium-ion secondary battery. Examples of battery applications include powering vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline cars, and diesel cars. In particular, it is preferable to use it as a power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or battery electric vehicles (BEVs). Furthermore, the battery in this disclosure may be used as a power source for mobile devices other than vehicles (e.g., railways, ships, aircraft), or as a power source for electrical products such as information processing devices. [Examples]
[0040] Fabrication of electrode stacks <Example 1> A fixing member having a thick film region and thin film regions at both ends was placed on a pair of opposing side surfaces of the electrode stack as follows. Specifically, when applying an ultraviolet-curable resin (Toagosei Co., Ltd., Aronics) to a pair of opposing side surfaces of the electrode stack using a dispenser, the amount of resin dispensed at the ends was adjusted to make the thickness of the resin thinner at the ends, including the ends, of the side surfaces of the electrode stack, and thicker in other areas. The resin was then cured by irradiating it with ultraviolet light, and the fixing member was placed. The thickness of the end of the thin film region of the fixing member was 0.4 mm, and the thickness of the thick film region of the fixing member was 1 mm. The length of the thin film region was 5 mm. <Comparative Example 1> The fixing member was arranged in the same manner as in Example 1, except that a solid member without a thin film region was placed on the side surface of the electrode stack.
[0041] "evaluation" The defect rate for detached fixing members was evaluated when 10 electrode laminates were fabricated for each of Example 1 and Comparative Example 1.
[0042] "result" In the electrode laminate of Example 1, which had a fixed member having a predetermined thick film region and a thin film region, the defect rate was 0%. In contrast, in the electrode laminate of Comparative Example 1, which had a fixed member without a thin film region, the defect rate was 40%. [Explanation of Symbols]
[0043] 10 batteries 11 Fixing member 11a Thin film area 11b Thick film area 11c terminal 12 Electrode Stack 13. Laminating film 14 Current collector foil 15 Current collector terminal
Claims
1. An electrode laminate in which a fixing member containing a curable resin is disposed on at least one side surface, The aforementioned fixing member has a thin film region and a thick film region, The thin film region is formed on at least one end of the fixing member, including the end of the side surface of the electrode stack, and the thick film region is formed on the portion other than the thin film region. Electrode stack.
2. The electrode laminate according to claim 1, wherein the fixing member has a shape in which the thickness gradually decreases toward the end in the thin film region.
3. The electrode laminate according to claim 1, wherein the fixing member has a stepped shape in the thin film region such that the thickness of the end is minimized.
4. The electrode laminate according to claim 1, wherein the fixing member has the thin film region at both ends, including the end.
5. The thickness of the fixing member is thinnest at the end, The thickness of the end portion is 50% or less of the thickness of the thick film region. The electrode laminate according to claim 1.
6. The electrode laminate according to claim 1, wherein the length of the thin film region is 1 mm or more.
7. The electrode laminate according to claim 1, wherein the thickness of the thick film region is 50 μm or more and 5 mm or less.
8. The electrode laminate according to any one of claims 1 to 7, and Laminate film sealing the electrode stack A battery containing a battery.