Charge / discharge inspection method for battery

Abstract

To provide an inspection method for charge / discharge of a battery which suppresses deformation even if a high load is applied to an electrode in order to cause a large current to flow.SOLUTION: A charge / discharge inspection method for a battery includes performing charge / discharge for a charge / discharge inspection by pressing a current probe 21 and a voltage probe 22 to a positive electrode terminal 12 and a negative electrode terminal 13 which are provided in an electrode body 11 of a battery 10. The positive electrode terminal 12 and the negative electrode terminal 13 include a notched part 12a and a notched part 13a in which one corner (side) of the positive electrode terminal and the negative electrode terminal is notched on faces on the opposite side of a side connected to the electrode body 11, such that a face is formed. When performing the charge / discharge inspection by pressing the probes to the corners of the electrode terminals, since the corners of the electrode terminals are thick and rigidity is strong, even if the probes are pressed with a high load and a large current flows, the deformation of the electrode terminals is suppressed and even if deformed, since they are the corners of the electrode terminals, influences upon assembly in a subsequent step are suppressed. Thus, the stable inspection can be performed by pressing the probes with the high load.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for inspecting the charge and discharge of a battery. [Background technology]

[0002] During the manufacture of secondary batteries, battery performance is tested by charging and discharging the secondary batteries. To connect the secondary battery to a charging / discharging device, a charging / discharging probe must be firmly clamped or pressed against the electrode terminals of the secondary battery to remove the oxide film on the electrode terminals. For this reason, in prior art such as Patent Document 1, the tip of the charging / discharging probe is clamped between the electrode terminals to connect them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-186105 Summary of the Invention [Problem to be solved by the invention]

[0004] As batteries become larger in capacity, larger currents are required during charge / discharge testing, which requires larger diameter charge / discharge probes and stronger pressing forces on the electrode terminals, resulting in significant deformation of the electrode terminals.

[0005] Therefore, an object of the present disclosure is to suppress deformation of the electrode terminals. [Means for solving the problem]

[0006] The present application discloses a method for inspecting the charge and discharge of a battery, in which a probe for charge and discharge is connected to a corner of an electrode terminal of the battery to perform the inspection. [Effects of the Invention]

[0007] According to the method of the present disclosure, the corners of the electrode terminals (positive electrode terminal, negative electrode terminal) are thick and highly rigid, so deformation can be suppressed even when a high load is applied to the electrodes to pass a large current. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view illustrating an external appearance of a battery during charge / discharge testing. [Figure 2] FIG. 2 is a diagram illustrating another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 shows one example of a battery charge / discharge inspection method (sometimes referred to as an "inspection method") according to one embodiment. In the inspection method, a current probe 21 and a voltage probe 22 are pressed against a positive electrode terminal 12 and a negative electrode terminal 13, respectively, of an electrode body 11 of a battery 10, and charging and discharging are performed for the charge / discharge inspection (for ease of viewing, in FIG. 1, the positive electrode terminal 12 and the current probe 21 and the voltage probe 22, and the negative electrode terminal 13 and the current probe 21 and the voltage probe 22 are shown separated from each other, but are pressed against each other during charging and discharging). This is explained in more detail below.

[0010] [Electrode body] The electrode body 11 has a positive electrode current collecting layer, a positive electrode composite layer, a separator layer, a negative electrode composite layer, and a negative electrode current collecting layer. In this embodiment, the positive electrode current collecting layer, the positive electrode composite layer, the separator layer, the negative electrode composite layer, the negative electrode current collecting layer, the negative electrode composite layer, the separator layer, the positive electrode composite layer, and the positive electrode current collecting layer are laminated in this order to form unit elements, and a plurality of these are laminated to form the electrode body 11. A positive electrode terminal 12 is electrically connected to the positive electrode current collecting layer of the electrode body 11, and a negative electrode terminal 13 is electrically connected to the negative electrode current collecting layer of the laminate 11. In this embodiment, the electrode body 11 is quadrangular in plan view (as viewed from the direction of arrow A in FIG. 1).

[0011] The positive electrode current collecting layer is laminated on the positive electrode composite layer to collect current from the positive electrode composite layer. The positive electrode current collecting layer is a rectangular foil in plan view, and in this embodiment is made up of a positive electrode current collecting foil, which is a metal foil, and a carbon layer laminated on the positive electrode current collecting foil. The carbon layer is laminated on the positive electrode composite layer, thereby laminating the positive electrode current collecting layer on the positive electrode composite layer. Examples of materials that make up the positive electrode current collecting foil include stainless steel, aluminum, nickel, iron, and titanium, and the carbon layer is made of a material containing carbon.

[0012] The positive electrode mixture layer has the positive electrode current collecting layer on one surface and a separator layer on the other surface. The positive electrode mixture layer has a rectangular sheet shape in plan view. The positive electrode mixture layer is a layer containing a positive electrode active material, and may further contain at least one of a solid electrolyte material, a conductive material, and a binder, as necessary. The positive electrode active material may be a known active material. Examples include cobalt-based (LiCoO2, etc.), nickel-based (LiNiO2, etc.), manganese-based (LiMn2O4, Li2Mn2O3, etc.), iron phosphate-based (LiFePO4, Li2FeP2O7, etc.), NCA-based (nickel, cobalt, aluminum compound), and NMC-based (nickel, manganese, cobalt compound). More specifically, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 and others. The solid electrolyte is preferably an inorganic solid electrolyte, because it has higher ionic conductivity and superior heat resistance compared to organic polymer electrolytes. Examples of inorganic solid electrolytes include sulfide solid electrolytes with Li ion conductivity and oxide solid electrolytes with Li ion conductivity. The binder is not particularly limited as long as it is chemically and electrically stable, and examples thereof include fluorine-based binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), rubber-based binders such as styrene butadiene rubber (SBR), olefin-based binders such as polypropylene (PP) and polyethylene (PE), and cellulose-based binders such as carboxymethyl cellulose (CMC). As the conductive material, carbon materials such as acetylene black (AB), ketjen black, and carbon fiber, and metal materials such as nickel, aluminum, and stainless steel can be used. The content of each component in the positive electrode mixture layer may be the same as in the past. The thickness of the positive electrode mixture layer is, for example, preferably 0.1 μm to 1 mm, more preferably 1 μm to 150 μm.

[0013] The separator layer (solid electrolyte layer) is a rectangular sheet in plan view, disposed between the positive electrode composite layer and the negative electrode composite layer, and contains a solid electrolyte material. The separator layer contains at least the solid electrolyte material. The solid electrolyte material can be considered to be the same as the solid electrolyte material described for the positive electrode composite layer.

[0014] The negative electrode mixture layer is a layer containing at least a negative electrode active material. The negative electrode mixture layer may contain a binder, a conductive material, and a solid electrolyte material as needed. The binder, conductive material, and solid electrolyte material can be considered to be similar to those of the positive electrode mixture layer. The negative electrode active material is not particularly limited, but in the case of constructing a lithium ion battery, examples of the negative electrode active material include carbon materials such as graphite and hard carbon, various oxides such as lithium titanate, Si and Si alloys, metallic lithium and lithium alloys, and the like. The negative electrode mixture layer is in the form of a rectangular sheet in plan view, with the separator layer laminated on one surface and the negative electrode current collecting layer laminated on the other surface. The content of each component in the negative electrode mixture layer may be the same as in the past. The thickness of the negative electrode mixture layer is, for example, preferably 0.1 μm to 1 mm, more preferably 1 μm to 150 μm.

[0015] The negative electrode current collecting layer is laminated on the negative electrode composite layer to collect current from the negative electrode composite layer. The negative electrode current collecting layer has a rectangular foil shape in a plan view and can be made of, for example, stainless steel, copper, nickel, carbon, or the like.

[0016] [Positive terminal, negative terminal] The positive electrode terminal 12 and the negative electrode terminal 13 are electrically conductive members, and are electrode terminals for electrically connecting each electrode to the outside. One end of the positive electrode terminal 12 is electrically connected to the positive electrode current collecting layer, and the other end is exposed to the outside as a terminal. One end of the negative electrode terminal 13 is electrically connected to the negative electrode current collecting layer, and the other end is exposed to the outside as a terminal.

[0017] In this embodiment, the positive electrode terminal 12 and the negative electrode terminal 13 are rectangular parallelepipeds, and the positive electrode terminal 12 and the negative electrode terminal 13 are disposed on opposite sides of the electrode body 11 . However, in this embodiment, as can be seen from Figure 1, the positive electrode terminal 12 and the negative electrode terminal 13 have a cutout portion 12a and a cutout portion 13a on the surface opposite to the side connected to the electrode body 11, where one corner (side) of the positive electrode terminal 12 and the negative electrode terminal 13 is cut out, thereby forming a surface.

[0018] The positive electrode terminal 12 and the negative electrode terminal 13 may be surface-treated to reduce the contact resistance with the current probe 21 and the voltage probe 22 .

[0019] [Current probe, voltage probe] The current probe 21 is a probe for current that is used when performing a charge / discharge test by pressing it against the positive electrode terminal 12 and the negative electrode terminal 13. The shape of the probe is not particularly limited, and any known probe can be used. The voltage probe 22 is a voltage probe that is pressed against the positive electrode terminal 12 and the negative electrode terminal 13 when performing a charge / discharge test. The shape of the probe is not particularly limited, and any known probe can be used.

[0020] [Charge / discharge test] The charge / discharge test checks whether the battery has any electrical abnormalities (capacity, resistance, self-discharge, etc.), and is carried out by charging and discharging the battery. Specifically, the charge / discharge test is performed by placing the current probe 21 and the voltage probe 22 so that they are pressed against the ends of the positive terminal 12 and the negative terminal 13, respectively, as shown by arrow B in Figure 1, and charging and discharging by passing a current through them.

[0021] In this embodiment, current probe 21 is pressed against the surface formed by cutouts 12 a and 13 a. In this embodiment, only cutouts 12 a and 13 a are provided for current probe 21, but a cutout may also be provided at the corner (side) opposite to the corner (side) where cutouts 12 a and 13 a are provided to form a surface against which voltage probe 22 is pressed.

[0022] According to the charge / discharge test of the present disclosure, a probe mark (a mark left on the terminal surface by passing current at the position where the probe is placed) is formed on at least one corner of the positive electrode terminal 12 and the negative electrode terminal 13.

[0023] [Other forms] Another embodiment is shown in Fig. 2. Fig. 2 is an enlarged view of a portion of the negative electrode terminal 13 and the electrode body 11 as viewed from the perspective of Fig. 1. The positive electrode terminal 12 can be considered in the same way. In the embodiment shown in Fig. 2, cutout portion 13a is not formed by cutting out one side of a rectangular parallelepiped, but by cutting out one vertex to form a surface. A probe may be pressed against this surface. Note that positive electrode terminal 12 and negative electrode terminal 13 have four vertices that are not in contact with electrode body 11, but in addition to the form shown in Fig. 2 in which one vertex is cut out, at least one of the other three may also be cut out to form a surface against which current probe 21 and voltage probe 22 may be pressed.

[0024] In the above embodiment, the notches are provided at the corners, but the notches do not necessarily have to be provided.

[0025] [Effects, etc.] According to the present disclosure, charge / discharge testing is performed by pressing a probe against the corner of an electrode terminal. However, because the corner of the electrode terminal is thick and rigid, deformation of the electrode terminal can be suppressed even when a large current is passed through it by pressing the probe against it with a high load. Furthermore, even if deformation occurs, since it is at the corner of the electrode terminal, the impact on assembly in subsequent processes can be suppressed. Furthermore, pressing the probe against it with a high load enables stable testing (reducing contact failures).

[0026] This also results in probe marks being formed on the corners of the electrode terminals, resulting in a battery having probe marks on at least one or more corners (or four corners) of the terminals for electrical connection to the outside. By detecting (seeing) the probe marks, it is possible to detect missed inspections, poor contact, and probe pin defects (wear).

[0027] If a notch is provided at the corner to allow surface contact at the corner, a large contact surface with the probe can be secured. [Explanation of symbols]

[0028] 10... Battery, 11... Electrode body, 12... Positive electrode terminal (electrode terminal), 13... Negative electrode terminal (electrode terminal), 21... Positive electrode probe, 22... Negative electrode probe

Claims

[Claim 1] A battery charge / discharge inspection method, comprising: The test is performed by connecting a charge / discharge probe to the corner of the electrode terminal of the battery. Battery charge / discharge inspection method.

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