JP5691286B2 - Manufacturing method of negative electrode plate - Google Patents

Description

  The present invention relates to a method for producing a negative electrode plate for a lithium ion secondary battery comprising a conductive current collector plate and a negative electrode active material layer formed thereon.

Conventionally, as a negative electrode plate for a lithium ion secondary battery, one having a conductive current collector plate and a negative electrode active material layer formed thereon is known. Carbon-based materials such as graphite have been mainly used for the negative-electrode active material constituting the negative-electrode active material layer. However, since the carbon-based material has a small capacity capable of occluding lithium ions, it increases the battery capacity. There was a problem that was difficult. Therefore, in recent years, use of a material that occludes lithium ions by generating a compound by reacting with lithium ions, such as silicon, silicon oxide, and tin oxide, as a negative electrode active material has been studied.
For example, Patent Documents 1 and 2 disclose lithium secondary batteries using a negative electrode active material that reacts with lithium ions to form a compound.

JP 2003-109589 A WO01 / 029913

  However, in the lithium ion secondary battery in which the negative electrode active material layer is formed by using the negative electrode active material that reacts with lithium ions to form a compound as described above, the negative electrode active material is associated with the insertion and extraction of lithium ions due to charge and discharge. The material expands and contracts greatly. For this reason, while charging / discharging was repeated, the negative electrode active material layer cracked and the negative electrode active material layer peeled off from the conductive current collector plate, resulting in poor durability.

  This invention is made | formed in view of this present condition, Comprising: It aims at providing the manufacturing method of the negative electrode plate which can make battery capacity large and can make durability high.

  First, a negative electrode plate for a lithium ion secondary battery, comprising: a conductive current collector plate; and a negative electrode active material layer that is formed on the conductive current collector plate and includes a negative electrode active material. The material includes a negative electrode active material that absorbs lithium ions by reacting with lithium ions to produce a compound, and stress generated in the negative electrode active material layer as the negative electrode active material expands and contracts during charge and discharge. It is preferable that the stress relaxation space for relaxation is a negative electrode plate provided in the negative electrode active material layer.

Since this negative electrode plate contains a negative electrode active material that occludes lithium ions by reacting with lithium ions to produce a compound, if a lithium ion secondary battery is manufactured using this negative electrode plate, the battery capacity is increased. it can.
In addition, since this negative electrode plate has the above-described stress relaxation space provided in the negative electrode active material layer, in the lithium ion secondary battery using this negative electrode plate, the negative electrode active material is absorbed along with the insertion and extraction of lithium ions due to charge / discharge. Although the substance expands and contracts, the stress generated in the negative electrode active material layer at that time can be relaxed. Therefore, cracks are unlikely to occur in the negative electrode active material layer, and the negative electrode active material layer can be prevented from peeling from the conductive current collector plate by repeated charge and discharge, and the durability of the lithium ion secondary battery can be increased.

Examples of the “negative electrode active material” include silicon, silicon oxide, and tin oxide. Further, the shape of the negative electrode plate is not particularly limited, and examples thereof include a rectangular plate shape, a disc shape, and a long plate shape.
Examples of the “stress relaxation space” include a large number of concave grooves provided in the negative electrode active material layer, and a large number of holes provided in the negative electrode active material layer. The groove may have a form that penetrates the negative electrode active material layer (a form in which the conductive current collector plate is exposed on the bottom surface of the groove) or a form that does not penetrate the negative electrode active material layer (the bottom of the groove has a negative electrode active material) It is good also as the form which consists of a layer.

  Further, in the negative electrode plate, the stress relaxation space is a plurality of concave grooves provided in the negative electrode active material layer, and the negative electrode active material layer is divided into a plurality of small negative electrode active material layers. These small negative electrode active material layers are preferably negative electrode plates that are a number of concave grooves that separate each other.

  In this negative electrode plate, the stress relaxation space is a large number of concave grooves that divide the negative electrode active material layer into a large number of small negative electrode active material layers and separate these small negative electrode active material layers from each other. For this reason, when the negative electrode active material expands / contracts due to the insertion / desorption of lithium ions by charging / discharging, each small negative electrode active material layer expands / contracts independently. Cracks are unlikely to occur. Even if a crack occurs in one small negative electrode active material layer, the crack does not extend to the adjacent small negative electrode active material layer. Therefore, the durability of the lithium ion secondary battery can be further increased.

  Further, in the negative electrode plate described above, the stress relaxation space may be a negative electrode plate that is a large number of holes provided in the negative electrode active material layer.

  In this negative electrode plate, the stress relaxation space is a large number of holes provided in the negative electrode active material layer. For this reason, when the negative electrode active material expands / shrinks due to insertion / extraction of lithium ions due to charge / discharge, the stress is relieved by these vacancies. It can suppress that a negative electrode active material layer peels from an electroconductive collector plate by repeating. Therefore, the durability of the lithium ion secondary battery can be further increased.

  Furthermore, in any of the above negative electrode plates, the negative electrode active material may be a negative electrode plate made of at least one of silicon and silicon oxide.

  Since silicon can occlude, for example, about 12 times as much lithium ions as graphite, battery capacity can be particularly increased by using silicon or silicon oxide as the negative electrode active material.

  Moreover, it is preferable to set it as a lithium ion secondary battery provided with the negative electrode plate in any one of said.

As described above, the negative electrode plate can occlude and release a large amount of lithium ions, and the negative electrode active material particles are hard to crack and have high durability. Therefore, the battery capacity of a lithium ion secondary battery using this negative electrode plate can be increased. While being able to enlarge, durability of a lithium ion secondary battery can be made high.
The shape of the lithium ion secondary battery is not particularly limited, and examples thereof include a coin shape, a cylindrical shape, and a square shape.

  Further, it is preferable that the vehicle is equipped with the lithium ion secondary battery and uses the electric energy stored in the lithium ion secondary battery as all or part of the driving energy of the driving source.

As described above, since the lithium ion secondary battery can increase the battery capacity and increase the durability, the performance of the vehicle equipped with the lithium ion secondary battery can be improved, or the performance can be reduced as it is. . Further, the durability of the vehicle can be increased.
Examples of the “vehicle” include an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, a hybrid railway vehicle, a forklift, an electric wheelchair, an electrically assisted bicycle, and an electric scooter.

  Moreover, it is preferable to use the lithium ion secondary battery and use the lithium ion secondary battery as at least one energy source.

As described above, since the lithium ion secondary battery can increase the battery capacity and increase the durability, the performance of the battery using the lithium ion secondary battery can be improved, or the performance is light as it is. Can be In addition, the durability of the battery-powered device can be increased.
Examples of the “battery-using device” include various home appliances driven by a battery, such as a personal computer, a mobile phone, a battery-powered electric tool, and an uninterruptible power supply, office equipment, and industrial equipment.

Further, a conductive current collector plate is formed on the conductive collector plate, and a negative electrode active material layer containing a negative electrode active material, a negative electrode plate for a lithium ion secondary battery, the negative active The material includes a negative electrode active material that absorbs lithium ions by reacting with lithium ions to produce a compound, and stress generated in the negative electrode active material layer as the negative electrode active material expands and contracts during charge and discharge. A method of manufacturing a negative electrode plate in which a stress relaxation space to be relaxed is provided in the negative electrode active material layer, wherein a portion to be the stress relaxation space on the conductive current collector plate is to be removed from the first material A first step of forming the negative electrode active material layer including the negative electrode active material after forming the portion; and after the first step, the first material forming the portion to be removed is removed to remove the stress relaxation space. On the negative electrode active material layer A second step, wherein the stress relaxation space is a plurality of concave grooves provided in the negative electrode active material layer, and the negative electrode active material layer is divided into a plurality of small negative electrode active material layers. A plurality of concave grooves for separating the small negative electrode active material layers from each other, and the first step forms the first material in a predetermined pattern corresponding to the shape of the numerous concave grooves on the conductive current collector plate. A resist forming step for forming a resist portion that is the portion to be removed, and of the conductive current collector plate, on the exposed portion where the conductive current collector plate is exposed without forming the resist portion, An active material layer forming step of forming a negative electrode active material layer, wherein the second step does not dissolve the components of the negative electrode active material layer, but is washed by using an organic solvent in which the first material is dissolved. Removing the first material forming the resist portion, Preferably from a method of preparing a negative electrode plate which is a cleaning groove forming step of forming the anode active material layer.

  In this method of manufacturing a negative electrode plate, in the first step, a negative electrode active material containing a negative electrode active material is formed after a portion to be removed made of the first material is formed on a portion of the conductive current collector plate that becomes a stress relaxation space. A material layer is formed, and in the second step, the first material forming the portion to be removed is removed to form a stress relaxation space in the negative electrode active material layer. By doing in this way, since a stress relaxation space can be easily provided in a negative electrode active material layer, a negative electrode plate can be manufactured easily.

  Further, in this negative electrode plate manufacturing method, in the resist forming step of the first step, a resist portion (to be removed) made of a first material in a predetermined pattern corresponding to the shape of a number of concave grooves on the conductive current collector plate. Part), and in the first active material layer forming step, a negative electrode active material layer is formed on the exposed portion of the conductive current collector plate. Then, in the second step (cleaning groove forming step), the first material forming the resist portion is removed by cleaning using the above-described organic solvent, and a large number of grooves are formed in the negative electrode active material layer. By doing in this way, since a ditch | groove can be easily formed in a negative electrode active material layer, a negative electrode plate can be manufactured easily.

  Further, in the above method for manufacturing a negative electrode plate, the active material layer forming step may be a negative electrode plate manufacturing method that is a sputter active material layer forming step of forming the negative electrode active material layer by a sputtering method.

  In this negative electrode plate manufacturing method, since the negative electrode active material layer is formed by the sputtering method in the active material layer forming step (sputter forming step), the negative electrode active material layer is formed on the exposed portion of the conductive current collector plate. Easy to do.

In one embodiment of the present invention for solving the above-described problem , a lithium ion battery including a conductive current collector plate and a negative electrode active material layer formed on the conductive current collector plate and including a negative electrode active material. A negative electrode plate for a secondary battery, wherein the negative electrode active material includes a negative electrode active material that occludes lithium ions by generating a compound by reacting with lithium ions, and the negative electrode active material expands during charge and discharge A method for manufacturing a negative electrode plate, wherein a stress relaxation space for relaxing stress generated in the negative electrode active material layer in accordance with shrinkage is provided in the negative electrode active material layer, wherein the stress relaxation is performed on the conductive current collector plate a portion to be a space, at the same time to form the portions to be removed composed of carbon, a first step of forming the anode active material layer including the negative active material, after the first step, the carbon forming the portions to be removed Remove the stress A second step of forming a sum space in the negative electrode active material layer, wherein the stress relaxation space is a large number of pores provided in the negative electrode active material layer, and the first step includes the negative electrode active material layer. A simultaneous formation step of forming a number of particles to be removed corresponding to a number of the vacancies, each of which is a portion to be removed, made of carbon, in the negative electrode active material layer, together with the formation of the material layer, 2 process, the component of the negative electrode active material layer is not removed, the carbon by heat treatment to remove, by removing the carbon forming said to be removed particles to form a large number of the pores in the anode active material layer It is a heat treatment void forming step, and the simultaneous forming step is a negative electrode plate manufacturing method which is an AIP simultaneous forming step in which the negative electrode active material layer and the particles to be removed are simultaneously formed by an arc ion plating method.

In this negative electrode plate manufacturing method, in the first step (simultaneous formation step), simultaneously with the formation of the negative electrode active material layer, a large number of particles to be removed (planned removal portions) made of carbon corresponding to a large number of pores are removed. In the second step (heat treatment vacancy formation step) formed in the active material layer, carbon forming the particles to be removed is removed by the heat treatment described above to form a large number of vacancies in the negative electrode active material layer. By doing in this way, since a void | hole can be easily formed in a negative electrode active material layer, a negative electrode plate can be manufactured easily.

  Further, in this negative electrode plate manufacturing method, the negative electrode active material layer and the particles to be removed are simultaneously formed by the arc ion plating method in the simultaneous forming step (AIP simultaneous forming step). Can be easily formed.

It is a longitudinal cross-sectional view of the lithium ion secondary battery which concerns on the reference form 1. FIG. 3 is a cross-sectional view of a negative electrode plate according to Reference Embodiment 1. FIG. 3 is a partial plan view of a negative electrode plate according to Reference Embodiment 1. FIG. It is explanatory drawing which shows a mode that the resist part was formed on the negative electrode current collecting plate regarding the manufacturing method of the negative electrode plate which concerns on the reference form 1. FIG. It is explanatory drawing which shows a mode that the negative electrode active material layer was formed on the exposed part of a negative electrode current collecting plate regarding the manufacturing method of the negative electrode plate which concerns on the reference form 1. FIG. It is a longitudinal sectional view of a lithium ion secondary battery according to the embodiment. It is sectional drawing of the negative electrode plate which concerns on embodiment . Relates to a method of manufacturing a negative electrode plate according to the embodiment is an explanatory view showing a state of forming the anode active material layer containing the to be removed particles to the negative electrode current collector plate. It is explanatory drawing which shows a filterless arc ion plating apparatus regarding the manufacturing method of the negative electrode plate which concerns on embodiment . It is a graph which shows the relationship between the charge / discharge cycle number and battery capacity about the lithium ion secondary battery of an Example, a reference example, and a comparative example. It is explanatory drawing which shows the vehicle which concerns on the reference form 2 . It is explanatory drawing which shows the hammer drill which concerns on the reference form 3 .

( Reference form 1 )
Hereinafter, reference embodiments will be described with reference to the drawings. 1 shows a lithium ion secondary battery 100 according to this reference embodiment 1. Further, in FIGS. 2 and 3, a negative electrode plate 131 according to this reference embodiment 1. The lithium secondary battery 100 is a coin cell and has a battery capacity of 0.7 mAh. The lithium secondary battery 100 includes a battery case 110, a positive electrode plate 121, a negative electrode plate 131, a separator 141, a gasket 150, and the like housed in the battery case 110.

  The battery case 110 includes a substantially bottomed cylindrical positive electrode case 111 located on the positive electrode side (lower side in FIG. 1) and a substantially bottomed cylindrical shape located on the negative electrode side (upper side in FIG. 1). A negative electrode case 113. The positive side case 111 and the negative side case 113 are electrically insulated from each other via an insulating gasket 150 formed in a substantially annular shape, and seal the inside of the battery case 110.

  In the battery case 110, a positive electrode plate 121 and a negative electrode plate 131 are stacked via a separator 141. Specifically, the positive electrode plate 121 is disposed at the center of the bottom portion 111 t of the positive electrode case 111 and is electrically connected to the positive electrode case 111. On the other hand, the negative electrode plate 131 is disposed at the center of the bottom 113 t of the negative electrode side case 113 and is electrically connected to the negative electrode side case 133. The battery case 110 is filled with a non-aqueous electrolyte 160.

  The separator 141 has a disk shape and is formed from a known porous resin such as PP or PE. The positive electrode plate 121 has a disc shape and is made of lithium metal. On the other hand, the negative electrode plate 131 has a disc shape, and includes a negative electrode current collector plate (conductive current collector plate) 132 made of copper foil, and a negative electrode active material layer 133 formed on the negative electrode current collector plate 132. (See FIGS. 1 to 3).

Among these, the negative electrode active material layer 133 is made of a negative electrode active material (crystalline silicon in the present embodiment 1 ) that occludes lithium ions by reacting with lithium ions to generate a compound. Note that, as the negative electrode active material, silicon oxide may be used instead of silicon, or both silicon and silicon oxide may be used.

The negative electrode active material layer 133 is provided with stress relaxation spaces 133m, 133m,... That relieve stress generated in the negative electrode active material layer 133 as the negative electrode active material expands and contracts during charge and discharge. . In the first embodiment , the stress relaxation spaces 133m, 133m,... Are a large number of concave grooves 133m, 133m,. These concave grooves 133m, 133m, ... divide the negative electrode active material layer 133 into a plurality of small negative electrode active material layers 133c, 133c, ..., and separate these small negative electrode active material layers 133c, 133c, ... from each other. ing. Each concave groove 131m is linearly formed with a width of 100 μm. Further, the concave grooves 131m, 131m,... Are arranged in a lattice shape with an interval of 400 μm. Thereby, each small negative electrode active material layer 133c has a rectangular shape in plan view with a side length of 400 μm.

Thus, since the negative electrode active material layer 133 is made of a negative electrode active material that occludes lithium ions when the negative electrode active material layer 133 reacts with lithium ions to produce a compound, the negative electrode plate 131 according to the first embodiment is the negative electrode plate. The battery capacity of the lithium ion secondary battery 100 using 131 can be increased. In particular, since silicon or silicon oxide is used for the negative electrode active material, the battery capacity can be particularly increased.
Further, since the negative electrode plate 131 is provided with concave grooves 131m, 131m,... As stress relaxation spaces in the negative electrode active material layer 133, in the lithium ion secondary battery 100 using the negative electrode plate 131, charging and discharging are performed. Although the negative electrode active material expands and contracts with the insertion and extraction of lithium ions, stress generated in the negative electrode active material layer 133 at that time can be relaxed. Accordingly, cracks are unlikely to occur in the negative electrode active material layer 133, and the negative electrode active material layer 133 can be prevented from peeling from the negative electrode current collector plate 132 due to repeated charge and discharge, and the durability of the lithium ion secondary battery 100 can be increased.

  Further, the grooves 131m, 131m,... Which are stress relaxation spaces divide the negative electrode active material layer 133 into a plurality of small negative electrode active material layers 133c, 133c,..., And these small negative electrode active material layers 133cl133c,. They are separated from each other. Therefore, when the negative electrode active material expands / shrinks along with the insertion / release of lithium ions by charging / discharging, the individual small negative electrode active material layers 133c, 133c,. The negative electrode active material layers 133c, 133c,. Even if a crack occurs in one small negative electrode active material layer 133c, the crack does not extend to the adjacent small negative electrode active material layer 133c. Therefore, the durability of the lithium ion secondary battery 100 can be further increased.

  Next, a method for manufacturing the negative electrode plate 131 and the lithium ion secondary battery 100 will be described. First, the negative electrode plate 131 is manufactured. That is, a negative electrode current collector plate 132 made of copper foil is prepared. Then, in the resist forming step of the first step, as shown in FIG. 4, a predetermined pattern corresponding to the shape of the numerous concave grooves 131m, 131m,... On one main surface of the negative electrode current collector plate 132. A resist portion JY1 that is a portion to be removed made of the first material is formed in a (lattice-like lattice shape).

  Specifically, a photosensitive paint containing TMAH (tetramethylammonium hydroxide), which is the first material, is applied on the negative electrode current collector plate 132, and then subjected to exposure and development for patterning, whereby a plan view is obtained. A lattice-like resist portion JY1 is formed. For example, the resist portion JY1 having a lattice shape in a plan view can be formed by applying a photosensitive paint containing TMAH (first material) by screen printing using a mask having a predetermined pattern.

Next, in the active material layer forming step of the first step, as shown in FIG. 5, of the negative electrode current collector plate 132, the exposed portion 132 r where the negative electrode current collector plate 132 is exposed without forming the resist portion JY <b> 1. A negative electrode active material layer 133 is formed thereover. In the first embodiment , a negative electrode active material (silicon) is deposited by sputtering, and a negative electrode active material including a plurality of small negative electrode active material layers 133c, 133c,... On the exposed portion 132r of the negative electrode current collector plate 132. Layer 133 is formed.

Next, in the cleaning groove forming process as the second process, the TMAH (first material) forming the resist portion JY1 is removed, and a large number of grooves 131m, 131m,. 133. Specifically, the component (silicon) of the negative electrode active material layer 133 is not dissolved, but the resist portion JY1 is removed by washing with an organic solvent (acetone in the present embodiment 1 ) in which TMAH (first material) is dissolved. The formed TMAH (first material) is removed to form the grooves 131m, 131m,. Thus, the above-described negative electrode plate 131 is formed (see FIGS. 2 and 3).

As described above, in the manufacturing method of the negative electrode plate 131 of the first embodiment , in the first step (resist formation step and active material layer formation step), in the portions that become the concave grooves (stress relaxation spaces) 131m, 131m,. A resist portion (a portion to be removed) JY1 made of TMAH (first material) is formed, and a negative electrode active material layer 133 is formed. More specifically, in the first resist forming step, a resist portion JY1 having a predetermined pattern is formed on the negative electrode current collector plate 132 in a predetermined pattern corresponding to the shape of the concave grooves 131m, 131m,. In the one active material layer forming step, the negative electrode active material layer 133 is formed on the exposed portion 132 r of the negative electrode current collector plate 132. Then, in the cleaning groove forming process as the second process, the TMAH (first material) forming the resist portion JY1 is removed to form the grooves 131m, 131m,. In this way, since the concave grooves 131m, 131m,... Can be easily formed in the negative electrode active material layer 133, the negative electrode plate 131 can be easily manufactured.

Furthermore, in the first embodiment , since the negative electrode active material layer 133 is formed by the sputtering method, the negative electrode active material layer 133 can be easily formed on the exposed portion 133r of the negative electrode current collector plate 132.
In the first embodiment , the components of the negative electrode active material layer 133 are not dissolved, but the first material that forms the resist portion JY1 is removed by washing with an organic solvent in which TMAH (first material) is dissolved to form a concave. Since the grooves 131m, 131m,... Are formed, the concave grooves 131m, 131m,.

  Separately, a positive electrode plate 121 made of lithium metal is prepared. In addition, a separator 141, a gasket 150, a positive electrode side case 111 and a negative electrode side case 113, and a non-aqueous electrolyte 160 are prepared. The positive electrode plate 121, the separator 141, and the negative electrode plate 131 are stacked in this order between the positive electrode case 111 and the negative electrode case 113. Further, a gasket 150 is disposed between the positive electrode side case 111 and the negative electrode side case 113, and a non-aqueous electrolyte 160 is injected. Thereafter, the peripheral edge portion of the positive electrode side case 111 is crimped, and the gap between the positive electrode side case 111 and the negative electrode side case 113 is sealed with a gasket 150. Thus, the lithium ion secondary battery 100 is completed.

( Embodiment )
Next, embodiments of the present invention will be described. Figure 6 shows a lithium ion secondary battery 200 according to the present embodiment, in FIG. 7, a negative electrode plate 231 according to this embodiment. In the present embodiment , the negative electrode plate 231 and the manufacturing method thereof are different from the negative electrode plate 131 and the manufacturing method thereof according to the first embodiment . Otherwise is the same as the Reference Embodiment 1, the description of the same parts as the above Reference Embodiment 1 will be omitted or simplified.

The negative electrode plate 231 constituting the lithium secondary battery 200 according to the present embodiment includes a negative electrode current collector plate 132 made of a copper foil similar to that of the first embodiment, and a negative electrode active material formed on the negative electrode current collector plate 132. Layer 233. Among these, the negative electrode active material layer 233 is made of a negative electrode active material that absorbs lithium ions by reacting with lithium ions to generate a compound (crystalline silicon in the present embodiment 1 ).

The negative electrode active material layer 233 is provided with stress relaxation spaces 233n, 233n,... That relieve stress generated in the negative electrode active material layer 233 as the negative electrode active material expands and contracts during charge and discharge. . In this embodiment , the stress relaxation spaces 233n, 233n,... Are a large number of holes 233n, 233n, ... provided in the negative electrode active material layer 233. These pores 233n, 233n,... Have an average diameter of about 70 μm and a porosity of 10 to 20% (15% in this embodiment ).

As described above, the negative electrode plate 231 according to the present embodiment is also composed of a negative electrode active material that occludes lithium ions by reacting with lithium ions to generate a compound, so that the lithium ion secondary using the negative electrode plate 231 is used. The battery capacity of the battery 200 can be increased.
Further, since the negative electrode plate 131 is provided with holes 231n, 231n,... As stress relaxation spaces in the negative electrode active material layer 233, the lithium ion secondary battery 200 using the negative electrode plate 231 is charged / discharged. Although the negative electrode active material expands and contracts as lithium ions are occluded / released, stress generated in the negative electrode active material layer 233 can be relaxed. Therefore, the negative electrode active material layer 233 is hardly cracked, and the negative electrode active material layer 233 can be prevented from peeling from the negative electrode current collector plate 132 due to repeated charge and discharge, and the durability of the lithium ion secondary battery 200 can be increased. Other, similar parts as the above Reference Embodiment 1 exhibits the same actions and effects as those in Reference Embodiment 1.

  Next, a method for manufacturing the negative electrode plate 231 and the lithium ion secondary battery 200 will be described. First, a negative electrode current collector plate 132 made of copper foil is prepared, and in the first formation process (AIP simultaneous formation process), as shown in FIG. In addition to forming the negative electrode active material layer 233, corresponding to the stress relaxation spaces (vacancies) 231n, 231n,..., Particles to be removed (planned removal portions) JY2, JY2,. Is formed in the negative electrode active material layer 233.

In the present embodiment , the negative electrode active material layer 233 and the particles to be removed JY2, JY2 are formed on the negative electrode current collector plate 132 by the filterless arc ion plating method using the filterless arc ion plating apparatus 300 schematically shown in FIG. , ... are formed simultaneously.

The filterless arc ion plating apparatus 300 includes a vacuum vessel 301, a holding jig 303, a target 305, an anode 307, an arc power supply 309, and a bias power supply 311. The vacuum vessel 301 is configured such that the inside is evacuated by a vacuum exhaust pump (not shown). In addition, the holding jig 303 is configured to be able to hold the negative electrode current collector plate 132 which is an object to be processed. Further, the target 305 constitutes a cathode. In this embodiment , a carbon target is used for the target 305. The arc power source 307 is connected between the cathode (target 305) and the anode 307. The bias power source 311 is configured to apply a bias voltage to the negative electrode current collector plate 132.

  In order to simultaneously form the negative electrode active material layer 233 and the particles to be removed JY2, JY2,. Cause it to occur. By this arc discharge AH, the target 305 is locally melted and molten particles (C droplets) DP are generated, and part of the target 305 is evaporated and simultaneously ionized to become an ionized evaporation substance. The molten particles DP and the ionized evaporation substance are accelerated by applying a bias voltage to the negative electrode current collector plate 132 from the bias power source 311, and are deposited on the negative electrode current collector plate 132. As a result, particles to be removed JY2, JY2,... From the molten particles DP are formed on the negative electrode current collector plate 132, and a negative electrode active material layer 233 is formed from the ionized evaporation material.

Next, in the heat treatment vacancy forming step, which is the second step, carbon (first material) forming the particles to be removed JY2 is removed, and a large number of vacancies 231n, 231n,. Layer 233 is formed. In this embodiment , the component (specifically, silicon) of the negative electrode active material layer 233 is not removed, but a heat treatment for removing carbon (first material) is performed to form particles to be removed JY2 from the negative electrode active material layer 233. The carbon (first material) is removed to form holes 231n, 231n,. Specifically, heat treatment is performed by heating at 500 ° C. for 5 hours in an oxygen atmosphere to form the holes 231n, 231n,. Thus, the above-described negative electrode plate 231 is formed (see FIGS. 6 and 7).

As described above, in the method of manufacturing the negative electrode plate 231 according to the present embodiment , in the simultaneous forming step (AIP simultaneous forming step) which is the first step, the portions that become the vacancies (stress relaxation spaces) 231n, 231n,. .. To be removed particles (planned removal portions) JY2, JY2,... Made of carbon (first material) and a negative electrode active material layer 233 are formed. More specifically, along with the formation of the negative electrode active material layer 233, a large number of particles to be removed JY2, JY2,... Corresponding to the holes 231n, 231n,. Then, in the heat treatment hole forming step, which is the second step, the carbon forming the removal scheduled portions JY2, JY2,... Is removed to form the holes 231n, 231n,. In this way, since the holes 231n, 231n,... Can be easily formed in the negative electrode active material layer 233, the negative electrode plate 231 can be easily manufactured.

Furthermore, in this embodiment , since the negative electrode active material layer 233 and the scheduled removal particles JY2, JY2,... Are formed simultaneously by the arc ion plating method, the negative electrode containing a large number of the scheduled removal particles JY2, JY2,. The active material layer 233 can be easily formed.
Further, in this embodiment , the carbon forming the particles to be removed JY2, JY2,... Is removed from the negative electrode active material layer 233 by heat treatment to form the holes 231n, 231n,. , 231n,... Can be easily formed. Other, similar parts as the above Reference Embodiment 1 exhibits the same actions and effects as those in Reference Embodiment 1.

(Example)
Subsequently, the result of the test conducted in order to verify the effect of this invention is demonstrated.
The lithium ion secondary battery 100 of the said reference form 1 was prepared as a reference example , and the lithium ion secondary battery 200 of the said embodiment was prepared as an Example of this invention . Further, as a comparative example, in the lithium ion secondary battery in which no stress relaxation space is provided in the negative electrode active material layer, that is, in the lithium ion secondary battery 100 of the above reference embodiment 1 , the negative electrode active material layer 133 has a concave groove 133m. A lithium ion secondary battery in a form not provided was prepared.

The relationship between the number of charge / discharge cycles and the battery capacity was examined for each of the lithium ion secondary batteries 100 of the examples , reference examples, and comparative examples. That is, in an environment of 25 ° C., the lithium ion secondary battery 100 and the like were charged until the battery voltage became 1.5V. Then, it discharged until the battery voltage became 0.01V with the constant current of 0.2C, and it charged again until the battery voltage became 1.5V with the constant current of 0.2C. This charge / discharge was repeated 35 times as one cycle, and the change in battery capacity was examined. The result is shown in the graph of FIG.

In the lithium ion secondary battery of the comparative example , the battery capacity was almost flat in the range of 0.6 to 0.7 mAh up to about 10 cycles. However, when the number of cycles exceeds 10, the battery capacity gradually decreases. When the number of cycles is 20, the battery capacity is less than 0.3 mAh, and when the number of cycles is 30 times, the battery capacity is 0.1 mAh. Below.

On the other hand, in the lithium ion secondary battery 100 of the reference example , the battery capacity was almost flat in the range of 0.6 to 0.7 mAh until the number of cycles was around 20. Thereafter, the battery capacity gradually decreased, but the battery capacity exceeded 0.3 mAh even when the number of cycles was 35. Moreover, in the lithium ion secondary battery 200 of the Example , the battery capacity was almost flat in the range of 0.6 to 0.7 mAh until the number of cycles was around 25 times. Thereafter, the battery capacity gradually decreased, but the battery capacity exceeded 0.5 mAh even when the number of cycles was 35.
From these results, it can be seen that by providing a stress relaxation space in the negative electrode active material layer, a decrease in battery capacity can be suppressed and the durability of the battery can be increased.

( Reference form 2 )
Next, a second reference embodiment will be described. A vehicle 700 according to the second embodiment is mounted with a plurality of lithium ion secondary batteries 100 according to the first embodiment , and is driven by using an engine 740, a front motor 720, and a rear motor 730 in combination as shown in FIG. It is a hybrid car.

Specifically, the vehicle 700 includes a vehicle body 790, an engine 740, a front motor 720, a rear motor 730, a cable 750, and an inverter 760 attached thereto. Further, the vehicle 700 includes an assembled battery 710 having a plurality of lithium ion secondary batteries 100, 100,... Inside thereof, and the electric energy stored in the assembled battery 710 is transmitted to the front motor 720 and the rear motor 730. It is used for driving.
As described above, since the lithium ion secondary battery 100 can increase the battery capacity and increase the durability, the performance of the vehicle 700 equipped with the lithium ion secondary battery 100 can be increased, or the performance can be maintained as it is. Weight can be reduced. Further, the durability of the vehicle 700 can be increased.

( Reference form 3 )
Next, a third reference embodiment will be described. As shown in FIG. 12, the hammer drill 800 of the third embodiment is a battery-operated device on which a battery pack 810 including the lithium ion secondary battery 100 of the first embodiment is mounted. Specifically, in this hammer drill 800, a battery pack 810 is accommodated in a bottom portion 821 of a main body 820, and this battery pack 810 is used as an energy source for driving the drill.
As described above, since the lithium ion secondary battery 100 can increase the battery capacity and increase the durability, the performance of the hammer drill 800 equipped with the lithium ion secondary battery 100 can be improved or the performance can be maintained as it is. Can be reduced in weight. Further, the durability of the hammer drill 800 can be increased.

In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, in the above embodiment and Reference Embodiments 1 to 3 , the negative electrode plates 131 and 231 in which the negative electrode active material layers 133 and 233 are formed only on one main surface of the negative electrode current collector plate 132 are illustrated. 133 and 233 can also be formed on both main surfaces of the negative electrode current collector plate 132.
Moreover, in the said embodiment and the reference forms 1-3 , although the negative electrode active material layers 133 and 233 are formed only from the negative electrode active material, a electrically conductive material, a binder, etc. can also be added to a negative electrode active material layer. .

Moreover, in the said embodiment and the reference forms 1-3 , although the positive electrode plate 121 and the one negative electrode plates 131 and 231 illustrated the lithium ion secondary battery 100 and 200 laminated | stacked via the separator 141, electrode The form of the body is not limited to this. For example, it may be a laminated electrode body in which a plurality of positive plates and a plurality of negative plates are alternately stacked via separators, or a wound type in which positive plates and negative plates are stacked via a separator and wound. It is good also as an electrode body.
Moreover, in the said embodiment and the reference forms 1-3 , although the positive electrode plate 121 is formed with lithium metal, the positive electrode plate 121 is not limited to such a thing. For example, the positive electrode plate may be composed of a positive electrode current collector plate (conductive current collector plate) made of metal foil and a positive electrode active material layer formed on the positive electrode current collector plate. The positive electrode active material layer can be formed from, for example, a positive electrode active material, a conductive agent, and a binder.

100,200 Lithium ion secondary battery 121 Positive electrode plate 131,231 Negative electrode plate 132 Negative electrode current collector plate (conductive current collector plate)
132r Exposed portion 133,233 Negative electrode active material layer 133c Small negative electrode active material layer 133m Concave groove (stress relaxation space)
233n hole (stress relaxation space)
300 Filterless Arc Ion Plating Device 700 Vehicle 710 Assembly Battery 800 Hammer Drill (Battery-Used Equipment)
810 Battery pack JY1 Resist part (to be removed)
JY2 particles to be removed (to be removed)

Claims (1)

A negative electrode plate for a lithium ion secondary battery, comprising: a conductive current collector plate; and a negative electrode active material layer formed on the conductive current collector plate and including a negative electrode active material,
The negative electrode active material includes a negative electrode active material that occludes lithium ions by generating a compound by reacting with lithium ions,
A method for producing a negative electrode plate, wherein a stress relaxation space for relaxing stress generated in the negative electrode active material layer in association with expansion and contraction of the negative electrode active material during charge and discharge is provided in the negative electrode active material layer,
A first step of forming the negative electrode active material layer containing the negative electrode active material at the same time as forming a portion to be removed made of carbon in the portion serving as the stress relaxation space on the conductive current collector plate;
After the first step, the second step of removing the carbon forming the removal planned portion and forming the stress relaxation space in the negative electrode active material layer,
The stress relaxation space is
A number of holes provided in the negative electrode active material layer,
The first step includes
Along with the formation of the negative electrode active material layer, a simultaneous formation step of forming a large number of particles to be removed corresponding to a large number of the vacancies, each of which is the planned removal portion made of carbon, in the negative electrode active material layer. ,
The second step includes
The negative electrode active material layer is not removed, but the carbon forming the particles to be removed is removed by a heat treatment to remove the carbon, and a plurality of pores are formed in the negative electrode active material layer. Process,
The simultaneous forming step includes
A method for producing a negative electrode plate, which is an AIP simultaneous forming step in which the negative electrode active material layer and the particles to be removed are simultaneously formed by an arc ion plating method.

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