WO2010089852A1

WO2010089852A1 - Case for sealed battery, sealed battery and method of manufacturing the sealed battery, vehicle having the battery, and battery-mounted device

Info

Publication number: WO2010089852A1
Application number: PCT/JP2009/051832
Authority: WO
Inventors: 鈴木　哲; 勝巳伊藤
Original assignee: トヨタ自動車株式会社
Priority date: 2009-02-04
Filing date: 2009-02-04
Publication date: 2010-08-12

Abstract

A case for a sealed battery comprises a battery case (11) having an opening part (21) on one side and a sealing plate (12) for closing the opening part (21) of the battery case (11). A power generating element (16) is contained in the battery case (11), and the battery case (11) is welded to the sealing plate (12) to seal the opening part (21) for forming a battery. An upper end surface (24) so welded to the sealing plate (12) as to be opposed to the sealing plate is formed at the edge side of the opening part (21) of the battery case (11). A peripheral part (31) so welded to the battery case as to be opposed to the upper end surface (24) is formed on the sealing plate (12). A groove (25) which forms the gap communicating with the inner space of the battery case (11) between the opposed surfaces of the upper end surface (24) and the peripheral part (31) when the upper end surface and the peripheral part are opposed to each other is formed in at least one of the upper end surface (24) and the peripheral part (31). The groove (25) is formed in the battery case (11) starting at the position of the inner surface of the battery case (11) to the position thereof fused during the welding in the plate thickness direction of the battery case (11).

Description

Sealed battery case, sealed battery and method for manufacturing the same, vehicle equipped with the battery, battery-equipped device

The present invention relates to a sealed battery case having a case for housing a power generation element and a sealing plate for sealing the power generation element, a sealed battery manufactured using the case, and a method for manufacturing the sealed battery. More specifically, the present invention relates to a sealed battery case, a sealed battery, and a manufacturing method thereof, in which both the case and the sealing plate are made of metal and the inside is sealed by welding them. Furthermore, it extends to vehicles equipped with the battery and battery-equipped devices.

Conventionally, there is a battery in which a power generation element is housed in a metal case. Usually, a metal sealing plate is welded to the opening of the case body, which has an opening on one side. As a result, the inside is sealed. Such batteries are used, for example, in vehicles and electrical equipment. For example, as a lithium ion secondary battery, there is a lithium ion secondary battery in which a sealing plate is put on an opening of a flat rectangular case having an opening on one side. Some of them are manufactured by laser welding around the entire periphery of the sealing plate. In such a case, high welding reliability such as sufficient welding strength and sufficient hermeticity is required for the welded portion.

For this purpose, for example, Patent Document 1 discloses a secondary battery in which a satin-like unevenness is formed in advance on a surface portion irradiated with a laser beam. According to the technique of this document, reflection of a laser beam is supposed to be suppressed. Furthermore, it is said that the surface area of the irradiated part is increased. For these reasons, it is said that the efficiency and reliability of welding are improved.
Japanese Patent Laid-Open No. 2005-116208

However, the conventional techniques described above have the following problems. During welding, high-temperature gas (fumes) may be generated from the weld location. In addition, the generated fumes may stay inside the weld. If it does so, it may remain as a bubble-like blowhole. If many blow holes are generated, there is a risk that the strength of the welded portion will be reduced and the gas leaks generated inside. Batteries with such locations are not suitable for mounting on vehicles or electrical equipment. Even with the above technology, these challenges still remain.

The present invention has been made in order to solve the problems of the conventional techniques described above. In other words, the problem is to provide a sealed battery case, sealed battery and manufacturing method thereof, a vehicle equipped with the battery, and a battery-equipped device that suppresses blowholes caused by fume and has high welding reliability. There is to do.

The sealed battery case according to the first aspect of the present invention, which has been made for the purpose of solving this problem, has a case body having an opening on one side, and a sealing member that closes the opening of the case body. A case for a sealed battery in which a power generation element is housed in a case body and the opening of the case body is sealed with a sealing member by welding to form a battery, and a sealing member and an edge of the opening of the case body A first facing surface to be welded facing is formed, a second facing surface to be welded facing the first facing surface is formed on the sealing member, and the first facing surface and the second facing surface are formed. And a recess that forms a gap communicating with the internal space of the case body between the opposing surfaces when the first opposing surface and the second opposing surface are opposed to each other. At least inside the case body in the thickness direction of the case body From a position corresponding to, those which are formed toward the outside of the case body.

According to the sealed battery case having the above configuration, the first opposing surface of the case body and the second opposing surface of the sealing member are opposed to each other and welded. A recess is formed between the opposing surfaces. Through this recess, the metal portion melted during welding is communicated with the inside of the case body. Therefore, even if fumes are generated in the molten metal, the fumes can escape into the case body. Thereby, the blowhole resulting from a fume can be suppressed. And the sealing part with high welding reliability is obtained.

Furthermore, in the above configuration, it is desirable that the outer end of the recess is located within a range that melts during welding. Such a thing can surely escape the fume.

Furthermore, in the above configuration, it is desirable that the recess is a groove formed discretely with respect to the circumferential direction of the opening of the case body. If it is such, the channel | path which escapes a fume can be formed, ensuring joining strength.

Furthermore, in the above configuration, it is desirable that the groove is formed over the entire thickness of the case body. If it is such, the location which melts at the time of welding and the inside of a case main body can be connected reliably.

Furthermore, in the above configuration, it is desirable that the pitch of the groove portion with respect to the circumferential direction of the opening of the case body is equal to or less than the pitch of the welded portion during welding. If it is such, even when pulsed laser welding is used, the welding location by each pulse can be made to correspond to a groove part, respectively.

Furthermore, in the above configuration, it is desirable that the depth of the groove is not more than 0.3 times the thickness of the case body. With this size, it is possible to ensure both the welding strength and the communication path.

The second aspect of the present invention includes a power generation element, a case main body having an opening on one side, and a sealing member that closes the opening of the case main body. A sealed battery in which the opening of the case body is sealed with a sealing member by welding, and a first facing surface facing the sealing member is formed on the edge of the opening of the case body, A recess that is formed with a second facing surface that faces the first facing surface, and that forms a gap between at least one of the first facing surface and the second facing surface that communicates with the internal space of the case body between the facing surfaces. The contact points of both opposing surfaces are welded from the outside over the entire circumference, and the recess melted during welding from at least the position corresponding to the inner surface of the case body in the thickness direction of the case body. Formed to a position A sealed battery are.

According to a third aspect of the present invention, a power generation element, a case main body having an opening on one surface, and a sealing member that closes the opening of the case main body, the power generation element is accommodated in the case main body, and welding is performed. A method for manufacturing a sealed battery by sealing an opening of a case body with a sealing member, wherein a first opposing surface that is welded facing the sealing member is formed on the edge of the opening as the case body A step of preparing a second facing surface to be welded facing the first facing surface as a sealing member, and an opening of the case body housing the power generation element The two facing surfaces are brought into contact with each other by closing with a sealing member, and the contact portion of both facing surfaces is welded from the outside over the entire circumference. In the preparation step, as a combination of the case body and the sealing member, 1st facing A recess that forms a gap communicating with the internal space of the case body between the opposing surfaces when the first opposing surface and the second opposing surface face each other at least one of the second opposing surface and the second opposing surface. This is a method for manufacturing a sealed battery in which a battery formed in the thickness direction of the battery from at least a position corresponding to the inner surface of the case body toward the outside of the case body is prepared.

In addition, the process to prepare may be that the member is manufactured in-house, or may be obtained by subcontracting, or purchased if the corresponding shape exists in the market. You may do it.

Further, in the above-described configuration, it is desirable to prepare a combination of the case main body and the sealing member in which the outer end portion of the recess is formed so as to be located within a range that melts during welding.

Further, the present invention extends to vehicles and battery-equipped devices equipped with a sealed battery according to the second aspect of the present invention.

According to the sealed battery case, the sealed battery and its manufacturing method, the vehicle equipped with the battery, and the battery-equipped device of the present invention, blowholes due to fume are suppressed and welding reliability is high. ing.

It is a perspective view which shows the secondary battery of this form. It is a top view which shows the battery case of this form. It is sectional drawing which shows the seam of the battery case and sealing plate before welding. It is sectional drawing which shows the joint line of the battery case and sealing plate after welding. It is sectional drawing which shows the joint line of the battery case and sealing plate after welding. It is explanatory drawing which shows the example of the shape of a square groove. It is explanatory drawing which shows the example of the shape of a round groove. It is explanatory drawing which shows the example of the shape of a triangular groove. It is explanatory drawing which shows the example of the shape of a trapezoid groove. It is explanatory drawing which shows the example of the shape of a wrinkle. It is sectional drawing which shows another example of the joint of the battery case before welding, and a sealing board. It is sectional drawing which shows another example of the joint of the battery case before welding, and a sealing board. It is sectional drawing which shows another example of the joint of the battery case before welding, and a sealing board. It is sectional drawing which shows another example of the joint of the battery case before welding, and a sealing board. It is sectional drawing which shows another example of the joint of the battery case before welding, and a sealing board. It is a side view which shows the battery pack which uses the secondary battery of this form. It is explanatory drawing which shows the vehicle using the secondary battery of this form. It is explanatory drawing which shows the hammer drill using the secondary battery of this form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Secondary battery 11 Battery case 12 Sealing plate 21 Opening part 24 Upper end surface 25 Groove 100 Battery pack 200 Vehicle 300 Hammer drill

Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. The present embodiment is an example in which the present invention is applied to a flat and square lithium ion secondary battery and its battery case.

The secondary battery 10 of this embodiment has a battery case 11 and a sealing plate 12 that seals one surface thereof, as shown in FIG. The boundary between the battery case 11 and the sealing plate 12 (shown by a thick black line in the figure) is the welded portion 13. The welded portion 13 is formed over the entire circumference of the sealing plate 12. Thereby, the battery case 11 and the sealing plate 12 are joined. Further, a positive electrode terminal 14 and a negative electrode terminal 15 which are external electrode terminals are respectively attached to the upper portion of the sealing plate 12 in the figure so as to protrude. The positive terminal 14 and the negative terminal 15 are connected to the respective electrodes of the power generation element 16 housed in the battery case 11.

The battery case 11 has a bottomed and flat box shape as shown in FIG. The upper part in the figure is the opening 21. That is, the battery case 11 has a bottom surface 22 and four side surfaces 23. A portion surrounded by the upper end surface 24 of the side surface 23 is the opening 21. A number of grooves 25 in the thickness direction of the side surface 23 are formed on the upper end surface 24 over the entire circumference of the opening 21. The groove 25 extends over the entire thickness of the side surface 23.

In this embodiment, the battery case 11 and the sealing plate 12 are made of the same metal material. For example, aluminum and iron are suitable. As the battery case 11 of this embodiment, a battery case having a thickness t of about 1 mm is used at least in the vicinity of the upper end surface 24 of the side surface 23. The battery case 11 corresponds to a case body, and the sealing plate 12 corresponds to a sealing member. The upper end surface 24 of the battery case 11 is the first opposing surface, and the surface (the lower surface in FIG. 3) on the side facing the upper end surface 24 of the peripheral portion 31 (see FIG. 3 described later) of the sealing plate 12 is the second. Corresponds to the facing surface.

The sealing plate 12 is a plate-like member that is placed on the upper end surface 24 of the battery case 11. That is, the peripheral portion of the sealing plate 12 is placed on the upper end surface 24. The opening 21 is covered with the sealing plate 12. A part of the cross section of the sealing plate 12 is shown in FIG. This figure shows the state of the cross section at the location of the groove 25 in the upper end surface 24. At a place other than the groove 25, the upper end surface 24 contacts the sealing plate 12. As shown in the figure, the sealing plate 12 has a peripheral portion 31 formed with a width s along the outer periphery, and a central portion 32 surrounded by the peripheral portion 31.

The peripheral portion 31 is a portion placed on the upper end surface 24 of the battery case 11 as shown in FIG. Further, the central portion 32 has a shape that is slightly lowered to the inside of the battery case 11 than the peripheral portion 31. Therefore, a step is formed between the central portion 32 and the peripheral portion 31. This figure shows a state in which the sealing plate 12 is merely placed on the battery case 11 and is not yet welded.

When the sealing plate 12 is placed on the battery case 11, as shown in FIG. 3, the upper end surface 24 of the battery case 11 is entirely covered by the peripheral portion 31 of the sealing plate 12. Further, as shown in this figure, the width s of the peripheral portion 31 is larger than the plate thickness t of the battery case 11. Therefore, in this state, the upper part of the groove 25 is covered. Both end portions of the groove 25 are opened to the outside and inside of the battery case 11, respectively. In the present embodiment, the depth H of the groove 25 is within a range satisfying the following expression 1 with respect to the plate thickness t.
0.03 × t ≦ H ≦ 0.3 × t (Formula 1)

As shown in FIG. 3, the secondary battery 10 of the present embodiment is obtained by placing a sealing plate 12 on a battery case 11 and performing laser welding on the joint. As a result, as shown in FIG. 4, a welded portion 13 is formed. In this embodiment, as indicated by a white arrow L in the drawing, the laser beam is irradiated from the left lateral direction in the drawing parallel to the overlapping surface of the battery case 11 and the sealing plate 12. Thereby, the vicinity of the upper end surface 24 of the battery case 11 and the peripheral portion 31 of the sealing plate 12 are partially melted together.

In this embodiment, a pulse laser such as a YAG laser is used for laser welding. Welding is performed over the entire circumference along the upper end surface 24 of the battery case 11 while slightly shifting so that the irradiation positions of the respective pulses partially overlap each other. In that case, the weld 13 formed for each pulse has a substantially hemispherical shape. Therefore, the cross-sectional shape is approximately semicircular as shown in FIG. In this figure, the deepest part of the welded part 13 by each pulse is shown. As shown in this figure, the depth d of the welded portion 13 is smaller than the plate thickness t of the battery case 11 even at the deepest portion. Further, the inner surface of the welded portion 13 faces the groove 25.

Next, FIG. 5 shows the AA cross section of FIG. The left end in the figure is the outer surface of the side surface 23 of the battery case 11 and is covered by the welded portion 13 without a gap. Further, the depth of the side surface 23 that is covered by the welded portion 13 without a gap is referred to as a welding depth D. This welding depth D cannot be adjusted strictly. That is, even if laser irradiation conditions such as irradiation intensity are set, the welding depth D is affected to some extent by the state of the joint. In this embodiment, the welding depth D is set so as to be about half of the plate thickness t.

Further, the pitch p of the groove 25 is equal to or less than the pitch r of the laser pulse. Therefore, the melted part by each pulse always faces one or more grooves 25. In FIG. 5, p = r. That is, the welded portions 13 by each one-time pulse irradiation are communicated with the inside of the battery case 11 through the corresponding grooves 25. The pitch r of the laser pulses is preferably in the range of (0.2R <r <0.5R) with respect to the bead width R of the laser.

Next, a method for manufacturing the secondary battery 10 of this embodiment will be described. First, the battery case 11, the sealing plate 12, the electrode winding body that becomes the power generation element 16, and the like are manufactured. The battery case 11 is formed with a plurality of grooves 25. For example, a bottomed box-shaped member may be formed by deep drawing aluminum material, and then a groove 25 may be formed on the upper end surface 24 of each side surface 23 by cutting or the like.

On the other hand, external electrode terminals (positive terminal 14 and negative terminal 15) are attached to the sealing plate 12. Then, the positive and negative electrodes of the electrode winding body serving as the power generation element 16 and the external electrode terminal of the sealing plate 12 are connected. Then, the electrode winding body is accommodated in the battery case 11. Then, the sealing plate 12 is placed on the battery case 11 and the joint is laser welded. A pulse laser is irradiated at equal intervals of pitch r, and makes a round around the sealing plate 12. At this time, since the groove 25 is formed in the battery case 11 as described above, the metal portion melted by the laser irradiation is communicated with at least one of the grooves 25.

Therefore, the fumes generated in the molten metal during welding can escape to the inside of the battery case 11 through the groove 25. Accordingly, no gas remains in the welded portion 13 after welding, so there is no blow hole. It should be noted that the entry of fume into the battery has no problem in terms of battery performance. Then, after the welding of the entire circumference is completed, the electrolytic solution is then injected into the battery case 11 using a liquid injection port or the like formed in the sealing plate 12. This completes the secondary battery 10.

In addition, what kind of cross-sectional shape of each groove | channel 25 may be sufficient. For example, as shown in FIG. 6, the rectangular groove 41 having a square cross-sectional shape may be used. Alternatively, as shown in FIG. 7, a round groove 42 having a semicircular cross section may be used. Alternatively, as shown in FIG. 8, a triangular groove 43 having a triangular cross section may be used. Alternatively, as shown in FIG. 9, a trapezoidal groove 44 having a trapezoidal cross section may be used. Further, instead of the groove 25, as shown in FIG. 10, a plurality of hook-like protrusions 45 formed on the upper end surface 24 can be used. In the case of the hook-shaped protrusion 45, the height corresponding to the groove depth H is the height of the hook-shaped protrusion 45.

Next, the inventors performed the following experiment 1. In Experiment 1, an aluminum battery case for testing was manufactured with a groove formed on the upper end surface. Further, the sealing plate 12 was welded by ordinary laser welding, and the state of the welded portion was observed. Here, a battery case having a thickness of 1 mm (t = 1) was used. A plurality of types having different groove depths H were manufactured. After welding, the average number of blow holes generated in the weld and the average pressure strength of the weld were measured and evaluated. In this experiment, a square groove 41 having a groove width and a groove depth H substantially equal to each other and having a substantially square cross section was used.

In Examples 1 to 5, the groove depth H is set to 0.03, 0.05, 0.10, 0.20, and 0.30 (mm). These satisfy the range of Equation 1 above. In Comparative Examples 1 and 2, the groove depth H is 0.40 and 0.50 (mm). Since this is a battery case with a plate thickness of 1 mm, these comparative examples are out of the range of Equation 1 above. Moreover, the comparative example 3 uses the conventional battery case which does not provide the groove | channel.

Each measurement method is as follows. The average number of blowholes was measured by taking a section of the welded portion 13 and counting it visually. That is, the vicinity of the welded portion 13 was hardened with resin, and the sealing plate 12 was polished in a direction to reduce its thickness. The number of blowholes was counted by cutting the welded portion 13 so that the cross section of the welded portion 13 was visible. At this time, the welding depth D was also measured. The average pressure strength was measured by making a through hole at a location other than the welded portion 13 in the welded battery case and injecting a liquid into the battery case from the through hole. And the pressure of the liquid when the welding part 13 was destroyed was measured.

Ten samples were prepared for each example, and the welding depth, the number of blow holes, and the pressure strength were measured, and the average of each measurement result was calculated and evaluated. The evaluation criteria were as follows.
When the average number of blow holes is 0 and the average pressure resistance is 4.0 MPa or more.
If either of them is not met ×

The result of Experiment 1 is as shown in Table 1. In all of Examples 1 to 5, welds in good condition were obtained. In Comparative Examples 1 and 2, the welding depth was small, and the average pressure strength did not reach the standard. This is probably because the depth of the groove is too large. In Comparative Example 3, many blow holes were observed. Therefore, it was confirmed that the preferable range of the groove depth H is a range satisfying the above-described expression 1.

Next, another example of the above embodiment is shown in FIG. In the battery case 51, a groove 52 that does not cover the entire plate thickness is formed instead of the groove 25. FIG. 12 shows a BB cross section of FIG. This figure shows a cross-sectional view near the upper end surface 24 of the side surface 23 in a state where it has not been welded yet. As illustrated, the groove 52 opens to the inner surface of the battery case 51 in the side surface 23. There is no opening to the outer surface.

In this case, the length L from the inner surface of the groove 52 is preferably within the range of the following formula 2 from the plate thickness t of the battery case 11 and the welding depth D.
L ≧ t−D (Formula 2)
However, this welding depth D is a set value. For example, in this embodiment, the set value of the welding depth D is half of the plate thickness t. In this example, any shape of the groove may be used. In this example, the depth of the groove may be larger than the range of Equation 1.

Next, the inventors performed the following experiment 2. That is, the performance of an example of a groove that does not penetrate in the thickness direction as shown in FIG. For this purpose, a groove that does not penetrate in the thickness direction was formed in the upper end surface of the test aluminum battery case. Several types of battery cases with different groove lengths were manufactured, and the sealing plate was welded by laser welding from the outside. The state of the welded part was observed.

Here, a battery case having a thickness of 1 mm (t = 1) was used, and a plurality of types having different groove lengths L were manufactured. The groove depth H was 0.05 mm in all cases. After welding, the average number of blow holes generated in the weld and the average pressure strength of the weld were measured and evaluated. In this experiment, a square groove was used as the groove shape.

In Examples 1 and 2, the groove length L is 0.70 and 0.50 mm. These satisfy the range of Equation 2 above. In Comparative Examples 1 to 3, the groove lengths L are 0.30, 0.20, and 0.10 (mm), respectively. Since the battery case t has a thickness of 1 mm, these comparative examples are out of the range of Equation 2 above. Moreover, the comparative example 4 uses the conventional battery case which does not provide the groove | channel. The measurement method and evaluation criteria are the same as in Experiment 1.

The result of Experiment 2 is as shown in Table 2. In the case of Example 1, welds in good condition were obtained for all the samples. In Example 2, although most of the samples were good, there was an example in which blowholes were slightly generated. Therefore, the evaluation was rated as “good”. In Comparative Examples 1 to 4, the generation of blow holes could not be suppressed. This is probably because the groove length was too small and the welding depth did not reach the groove. Therefore, it was confirmed that the preferable range of the groove length L is a range satisfying the above-described Expression 2.

That is, as the battery case 11 of the present embodiment, the groove 25 having a size in a range satisfying the formula 1 or the formula 2 may be formed. If the groove penetrates in the plate thickness direction, the above equation 1 is satisfied, and if the groove does not penetrate, the equation 2 is satisfied. If it is such, it will become possible to communicate with the inside of the battery case 11 for each melting range by each laser pulse during welding.

In other words, a groove may be formed so as to enable such communication. Other examples are shown in FIGS. In the example of FIG. 13, vertical grooves 61 in the direction along the side surface of the battery case 11 (up and down direction in the figure) are formed at positions slightly outside the welding depth D. At the same time, one or more lateral grooves 62 that communicate the longitudinal grooves 61 and the inside of the battery case 11 are formed. Further, in the example of FIG. 14, a step is formed slightly outside the welding depth D, and the inner surface side is a recess 63.

Also, the groove depth is not necessarily constant. You may make it become deep gradually from the external side of a battery case toward an internal side. For example, a groove having a shape of a part of a cone or a pyramid may be used. Alternatively, the same effect can be obtained by forming a groove on the back surface of the sealing plate instead of forming the groove on the battery case. In this case, as shown in FIG. 15, it is desirable that the groove 64 extends to a position further inside than the thickness t of the side surface 23. Or you may form in the position which does not mutually interfere in both a case and a sealing board. Further, for example, the concave portion may be formed by appropriately roughening the surface instead of the groove at the position where the groove is formed in the above examples. This is also included in the method of forming the recess.

As described in detail above, according to the secondary battery 10 of this embodiment, the groove 25 is formed in the upper end surface 24 of the battery case 11 before welding. Therefore, when the sealing plate 12 is placed on the upper end surface 24 and laser welding is performed, the molten metal communicates with the inside of the battery case 11 through the groove 25. Therefore, the occurrence of blow holes in the welded portion 13 is prevented. As a result, the generation of blowholes due to fume is suppressed, and a secondary battery with high welding reliability can be obtained.

Next, a usage example when the secondary battery 10 of the present embodiment is used in various devices will be described. For example, as shown in FIG. 16, a battery pack 100 using a plurality of secondary batteries 10 is manufactured and used. A plurality of secondary batteries 10 are arranged such that the side surfaces (large area surfaces) of adjacent secondary batteries 10 are in contact with each other so that the external electrode terminals are arranged on the same side. Further, the restraint plates 110 are brought into contact with both sides thereof, and the restraint plates 110 are fastened with the restraint screws 111 and the nuts 112. Thereby, each secondary battery 10 can be restrained and used at a restraining pressure suitable for use. Furthermore, the positive electrode terminal 14 and the negative electrode terminal 15 of each secondary battery 10 are connected in series in order to form a battery pack 100 that is mounted on various devices.

The battery pack 100 can be used by being mounted on a vehicle 200 as shown in FIG. 17, for example. The vehicle 200 is a hybrid vehicle that is driven by using an engine 240, a front motor 220, and a rear motor 230 in combination. This vehicle 200 includes a vehicle body 290, an engine 240, a front motor 220, a rear motor 230 attached thereto, a cable 250, an inverter 260, and a battery pack 100 having a plurality of secondary batteries 10 therein.

The vehicle may be a vehicle that uses battery-generated electric energy for all or a part of its power source. For example, an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, a hybrid railway vehicle, a forklift, an electric vehicle Wheelchairs, electric assist bicycles, electric scooters, etc. are listed.

Alternatively, the battery pack 100 can be used for a battery-equipped device as shown in FIG. Shown in this figure is a hammer drill 300 on which a battery pack 100 including the secondary battery 10 of this embodiment is mounted. The hammer drill 300 is a battery-equipped device having a battery pack 100 and a main body 320. The battery pack 100 is detachably accommodated in the bottom 321 of the main body 320 of the hammer drill 300.

The battery-equipped device may be any device equipped with a battery and using it as at least one energy source. For example, a personal computer, a mobile phone, a battery-powered electric tool, an uninterruptible power supply, etc. Various types of home appliances, office equipment, and industrial equipment driven by In addition to the battery pack 100, devices that can be used with a single battery that is not in an assembled battery state are also included.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, not only lithium ion secondary batteries but also sealed batteries can be widely applied. Further, the outer shape of the battery is not limited to a flat box shape, and can be applied to a cylindrical battery.

Claims

A case main body having an opening on one side; and a sealing member that closes the opening of the case main body. The power generation element is accommodated in the case main body, and the opening of the case main body is sealed by the sealing member by welding. In a sealed battery case that becomes a battery by sealing
A first opposing surface welded to face the sealing member is formed on the edge of the opening of the case body,
The sealing member is formed with a second opposing surface that is welded facing the first opposing surface,
When at least one of the first opposing surface and the second opposing surface faces the first opposing surface and the second opposing surface, a gap communicating with the internal space of the case body is defined as both opposing surfaces. A recess formed between them,
The sealed battery case is characterized in that the recess is formed in the thickness direction of the case body from at least a position corresponding to the inner surface of the case body toward the outside of the case body.
The sealed battery case according to claim 1, wherein the outer end of the recess is
A sealed battery case characterized by being located within a range that melts during welding.
The sealed battery case according to claim 1 or 2, wherein the recess is
A sealed battery case, wherein the case is a groove formed discretely with respect to the circumferential direction of the opening of the case body.
The sealed battery case according to claim 3, wherein the groove is
A sealed battery case characterized by being formed over the entire thickness of the case body.
In the sealed battery case according to claim 3 or claim 4,
The pitch of the arrangement of the grooves with respect to the circumferential direction of the opening of the case body is
A sealed battery case characterized by having a pitch equal to or less than a pitch of welding points during welding.
In the sealed battery case according to claim 4,
The sealed battery case, wherein the depth of the groove is 0.3 times or less the plate thickness of the case body.
A power generation element; a case main body having an opening on one side; and a sealing member that closes the opening of the case main body. The power generation element is housed in the case main body and welded to the case by the sealing member. In a sealed battery in which the opening of the main body is sealed,
A first opposing surface facing the sealing member is formed on an edge of the opening of the case body;
A second facing surface facing the first facing surface is formed on the sealing member;
At least one of the first facing surface and the second facing surface is formed with a recess that forms a gap communicating with the internal space of the case body between the facing surfaces.
The contact points on both opposing surfaces are welded from the outside over the entire circumference,
The sealed battery is characterized in that the recess is formed in a thickness direction of the case body from at least a position corresponding to the inner surface of the case body to a position melted during welding.
A power generation element, a case main body having an opening on one side, and a sealing member that closes the opening of the case main body, the power generation element is accommodated in the case main body, and the case main body by the sealing member by welding In the manufacturing method of a sealed battery by sealing the opening of
The case body is prepared with a first opposing surface formed on the edge of the opening facing the sealing member and facing the sealing member, and as the sealing member facing the first opposing surface. Preparing a second opposing surface to be welded;
A step of closing the opening of the case body containing the power generation element with the sealing member so that the opposing surfaces come into contact with each other, and welding the contact points of the opposing surfaces from the outside over the entire circumference,
In the step of preparing, as the combination of the case body and the sealing member, the first facing surface and the second facing surface are made to face at least one of the first facing surface and the second facing surface. Sometimes, a recess that forms a gap communicating with the internal space of the case body between the opposing surfaces is formed at least from the position corresponding to the inner surface of the case body in the thickness direction of the case body. A method for producing a sealed battery, characterized in that a battery formed toward the surface is prepared.
In the manufacturing method of the sealed battery according to claim 8,
In the preparing step, as a combination of the case main body and the sealing member, a sealed battery is prepared in which the outer end portion of the recess is formed so as to be located within a range that melts during welding. Manufacturing method.
A vehicle comprising the sealed battery according to claim 7.
A battery-mounted device comprising the sealed battery according to claim 7.