Metal shell and battery

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a metal shell and a battery, a first shell and a second shell are respectively formed by folding a substrate along a first straight line; the first shell is in a flat plate shape. The second shell is provided with a first accommodating groove and a second accommodating groove which are arranged at an interval, and the first accommodating groove and the second accommodating groove are both formed by being concave inwards in the direction away from the first shell; one side surface of the first shell and one side surface of the second shell are oppositely arranged, the edges of the first shell and the second shell are connected, so that the first shell seals the first accommodating groove and the second accommodating groove, the first accommodating groove is used for accommodating the pole core, and the second accommodating groove is used for exhausting or injecting liquid. According to the metal shell and the battery provided by the embodiment of the invention, during liquid injection formation, the electrolyte stored in the second accommodating groove enters the first accommodating groove to infiltrate and supplement the electrolyte, and gas generated by formation enters the second accommodating groove from the first accommodating groove, so that complicated operation of blocking a liquid injection hole for multiple times in the prior art is not needed.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to a metal shell and a battery. Background Art

[0002] At present, many lithium battery filling processes usually include primary filling and secondary filling. After the primary filling, formation is required, that is, through a high-temperature aging room, the electrolyte is allowed to penetrate into the electrode and the diaphragm, participate in the chemical reaction, and realize the conversion of chemical energy into electrical energy; the secondary filling is the process of replenishing the electrolyte after formation.

[0003] Since gas is generated during the formation process, it needs to be open (usually in a continuous negative pressure state), while the injection hole needs to be closed at other times. Therefore, the industry usually seals the injection hole with a rubber plug after the first injection, removes it before the formation, seals it again after the formation, and removes it before the second injection. As can be seen from the above, the injection formation process of the prior art is complicated. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to provide a metal shell and a battery in view of the problem that the liquid injection and formation process in the prior art is complicated.

[0005] To solve the above technical problems, on the one hand, an embodiment of the present invention provides a metal shell, comprising a first shell and a second shell respectively formed by folding a substrate along a first straight line;

[0006] The first shell is in the shape of a flat plate;

[0007] The second shell is provided with a first accommodating groove and a second accommodating groove arranged at intervals, and the first accommodating groove and the second accommodating groove are both recessed in a direction away from the first shell;

[0008] One side surface of the first shell and one side surface of the second shell are arranged opposite to each other, and the outer edges of the first shell and the second shell are fixedly connected by welding and sealing, so that the first shell closes the first receiving groove and the second receiving groove, and the first receiving groove is used to receive the pole core;

[0009] The volume of the first containing tank is greater than or equal to the volume of the second containing tank.

[0010] Optionally, the first accommodating groove is close to a first straight line, and the second accommodating groove is located on a side of the first accommodating groove away from the first straight line;

[0011] The second housing is provided with a first groove and a second groove opening outward, the first groove is connected to the second receiving groove, and the second groove is connected to the second receiving groove;

[0012] The first groove and the second groove are used to place the positive electrode cover plate assembly and the negative electrode cover plate assembly of the battery respectively.

[0013] Optionally, it further comprises a first cutting piece and a second cutting piece, the first cutting piece and the first shell are integrally formed, and the first cutting piece is arranged on a side of the first shell away from the first straight line;

[0014] The second cutting piece and the second shell are integrally formed, and the second cutting piece is arranged on a side of the second shell away from the first straight line.

[0015] Optionally, the length of the first accommodating groove is the same as the length of the second accommodating groove.

[0016] Optionally, the ratio of the cross-sectional area of ​​the first receiving groove to the cross-sectional area of ​​the second receiving groove is 1:0.05 to 1:0.5.

[0017] Optionally, a depth of the first accommodating groove is greater than or equal to a depth of the second accommodating groove.

[0018] Optionally, the depth of the first receiving groove is 5-40 mm;

[0019] The depth of the second receiving groove is 2-20 mm.

[0020] Optionally, the distance between the first accommodating groove and the second accommodating groove is X, the depth of the first accommodating groove is H, and 3H≥X≥0.5H.

[0021] Optionally, the substrate has a thickness of 0.1-0.4 mm.

[0022] On the other hand, an embodiment of the present invention further provides a battery, comprising the above-mentioned metal shell.

[0023] According to the metal shell and battery of the embodiments of the present invention, during liquid injection formation, the electrolyte stored in the second holding tank enters the first holding tank for infiltration and replenishment, and the gas generated by the formation enters the second holding tank from the first holding tank, eliminating the need for the complicated operation of plugging the liquid injection holes multiple times as in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is an overall schematic diagram of the manufacturing process of the metal shell provided by the first embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of an expanded substrate of a metal shell provided in a first embodiment of the present invention;

[0026] Figure 3 is a schematic side view of a metal housing provided by a first embodiment of the present invention;

[0027] Figure 4 1 is a schematic diagram of the exhaust of the second containing groove of the metal shell provided by the first embodiment of the present invention after being flattened;

[0028] Figure 5 It is a schematic diagram of the whole battery provided by the second embodiment of the present invention.

[0029] The reference numerals in the specification are as follows:

[0030] 1. Base plate; 11. First shell; 12. Second shell; 2. First receiving groove; 3. Second receiving groove; 4. First groove; 5. Second groove; 6. First straight line; 7. Liquid injection edge; 81. First cutting piece; 82. Second cutting piece. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] First embodiment

[0033] like Figures 1 to 3 As shown, the metal shell provided in the first embodiment of the present invention includes a first shell 11 and a second shell 12 formed by folding a substrate 1 along a first straight line 6. In other words, the first shell 11 and the second shell 12 are integrally formed. The first shell 11 and the second shell 12 are artificially divided into the first shell 11 and the second shell 12 after the flat substrate 1 is folded along the first straight line 6. The first shell 11 is in the shape of a plate; the second shell 12 is provided with a first receiving groove 2 and a second receiving groove 3 arranged at intervals, and the first receiving groove 2 and the second receiving groove 3 are both recessed in a direction away from the first shell 11. In this embodiment, the first receiving groove 2 and the second receiving groove 3 are formed by stamping. One side surface of the first shell 11 and one side surface of the second shell 12 are arranged oppositely, and the edge of the first shell 11 and the edge of the second shell 12 are welded and sealed, so that the first shell 11 closes the first receiving groove 2 and the second receiving groove 3, the first receiving groove 2 is used to accommodate the pole core, and the second receiving groove 3 is used for exhaust or injection.

[0034] In the liquid injection process of the second receiving tank 3 of the present invention, the two edges of the substrate 1 adjacent to the first straight line 6 are welded, and there is only one unwelded edge between the first shell 11 and the second shell 12, which is the edge for electrolyte injection, and is called the liquid injection edge 7. The electrolyte enters the second receiving tank 3 through the liquid injection edge 7 and then flows into the first receiving tank 2. The second receiving tank 3 is a liquid injection bag, and electrolyte can also be stored in the liquid injection bag. In the subsequent infiltration process, the liquid in the liquid injection bag can gradually infiltrate into the pole core, and the liquid injection is completed at one time and the liquid injection is fast, and the processing cycle is greatly shortened.

[0035] Reference Figure 3 and Figure 4 In the formation process, the second containing tank 3 is an exhaust bag, and the gas generated by the electrode core during the formation process is discharged from the first containing tank 2 into the second containing tank 3 for collection. Finally, the second containing tank 3 is flattened by external equipment to achieve one-time gas discharge, and there is no need for continuous vacuum exhaust during the formation process.

[0036] During the injection, the second receiving tank 3 stores excess electrolyte to enter the first receiving tank 2 for infiltration and replenishment of electrolyte at a later stage. The gas generated by the formation enters from the first receiving tank 2 and accumulates in the second receiving tank 3. In this embodiment, during the injection formation, after the excess or spare electrolyte is pre-injected into the second receiving tank 3, the injection edge 7 is temporarily closed. After the formation is completed, the gas in the second receiving tank 3 is emptied once and for all, without the need to close the injection hole multiple times as in the prior art. It should be noted that the metal shell in this embodiment is not an aluminum-plastic film shell, but a shell made of metal with a certain hardness. The traditional soft-packed aluminum-plastic film is relatively poor in sealing compared to the present application because the soft-packed aluminum-plastic film adopts hot melting, not laser welding in the present application. And the poor thermal conductivity of the soft-packed aluminum-plastic film makes the heat dissipation of the battery poor, and then the soft-packed aluminum-plastic film is easy to cause the battery to have a low service life.

[0037] In this embodiment, the first receiving groove 2 is close to the first straight line 6, and the second receiving groove 3 is located on the side of the first receiving groove 2 away from the first straight line 6. The second housing 12 is provided with a first groove 4 and a second groove 5 opening outward, respectively, the first groove 4 is connected to the second receiving groove 3, and the second groove 5 is connected to the second receiving groove 3. The first groove 4 and the second groove 5 are respectively used to place the cover assembly of the battery.

[0038] Reference Figure 2 and Figure 3 In this embodiment, the first groove 4 and the second groove 5 can be arranged on opposite sides of the first accommodating groove 2, or can be arranged on the same side of the first accommodating groove 2. This is not limited in this embodiment and is determined by actual application.

[0039] The substrate 1 further includes a first cutting piece 81 and a second cutting piece 82. The first cutting piece 81 and the first shell 11 are integrally formed, and the first cutting piece 81 is arranged on a side of the first shell 11 away from the first straight line 6. The second cutting piece 82 and the second shell 12 are integrally formed, and the second cutting piece 82 is arranged on a side of the second shell 12 away from the first straight line 6. The projections of the first cutting piece 81 and the second cutting piece 82 on the first shell 11 partially or completely overlap, and the first cutting piece 81 and the second cutting piece 82 are arranged opposite to each other. The first cutting piece 81 and the second cutting piece 82 are clamped by a clamp of an external device or manually, respectively, to open the unwelded edges between the first shell 11 and the second shell 12, thereby facilitating liquid injection.

[0040] In this embodiment, the first cutting piece 81 and the second cutting piece 82 are retained. In other embodiments, for aesthetic and volume considerations, after the injection edge 7 is welded, the first cutting piece 81 and the second cutting piece 82 can be cut off so that the metal shell is in a cube shape.

[0041] In this embodiment, the volume of the first receiving tank 2 is greater than or equal to the volume of the second receiving tank 3. The second receiving tank 3 in the metal shell is used as a liquid storage bag in the subsequent liquid injection process of the battery processing, and can be used to temporarily store the electrolyte required for the infiltration of the battery cell in the first receiving tank 2. During the infiltration process of the battery cell, the electrolyte stored in the second receiving tank 3 will gradually penetrate into the first receiving tank 2. In addition, the second receiving tank 3 is used as an exhaust bag in the subsequent formation process of the battery processing, and can be used to temporarily store the gas generated by the battery formation. After the formation process is completed, the second receiving tank 3 can be separated from the first receiving tank 2 by cutting, or the second receiving tank 3 can be flattened by exhausting, so that the metal shell forms a heat dissipation fin at the second receiving tank 3. Therefore, under the premise of meeting the processing requirements of the battery cell in the first receiving tank 2, the volume of the second receiving tank 3 is as small as possible, and it is bound to make the volume of the first receiving tank 2 greater than or equal to the volume of the second receiving tank 3.

[0042] The length of the first receiving groove 2 is the same as that of the second receiving groove 3. In this embodiment, the volume of the first receiving groove 2 is larger than that of the second receiving groove 3, but the lengths of the two are the same, and the length direction of the second receiving groove 3 is parallel to the first straight line 6. The ratio of the cross-sectional area of ​​the first receiving groove 2 to the cross-sectional area of ​​the second receiving groove 3 is 1:0.05 to 1:0.5. The cross-sectional area of ​​the first receiving groove 2 is related to the cross-sectional area of ​​the second receiving groove 3. The larger the cross-sectional area of ​​the first receiving groove 2, the larger the cross-sectional area of ​​the second receiving groove 3. Generally speaking, under the premise that the lengths of the first receiving groove 2 and the second receiving groove 3 are the same, the cross-sectional area of ​​the first receiving groove 2 is 6 times the cross-sectional area of ​​the second receiving groove 3, which can meet the exhaust and liquid injection requirements of the battery cell inside the first receiving groove 2 during the processing process, that is, the ratio of the cross-sectional area of ​​the first receiving groove 2 to the cross-sectional area of ​​the second receiving groove 3 is 1:0.166. If the ratio of the cross-sectional area of ​​the first receiving groove 2 to the cross-sectional area of ​​the second receiving groove 3 is less than 1:0.05, the second receiving groove 2 will not be able to meet the exhaust requirements of the formation in the subsequent battery processing of the metal shell, and the gas in the formation process will cause irreversible damage to the metal shell. If the ratio of the cross-sectional area of ​​the first receiving groove 2 to the cross-sectional area of ​​the second receiving groove 3 exceeds 1:0.5, the volume of the entire metal shell increases, especially the proportion of the second receiving groove 3 is too large, which will affect the overall size of the battery after the metal shell is processed, which is not conducive to the arrangement of battery modules and battery packs.

[0043] In this embodiment, the depth of the first receiving groove 2 is 5-40mm, and the depth of the first receiving groove 2 is determined by the subsequent battery capacity requirements. The larger the battery capacity, the larger the volume of the first receiving groove, and the correspondingly larger the depth of the first receiving groove. In addition, the depth of the first receiving groove 2 is affected by the thickness of the substrate 1. In order to ensure the structural strength of the first receiving groove 2, it is preferred that when the thickness of the substrate 1 is 0.2mm, the depth of the first receiving groove 2 is controlled between 10-14mm, preferably 12.1mm.

[0044] The depth of the second receiving groove 3 is 2-20mm. The depth of the second receiving groove 3 is related to the battery capacity in the first receiving groove 2. The larger the battery capacity, the larger the volume of the corresponding second receiving groove 3, and the larger the depth of the corresponding second receiving groove 3. In addition, the depth of the second receiving groove 3 is affected by the thickness of the substrate 1. In order to ensure the structural strength of the second receiving groove 3, it is preferred that the thickness of the substrate 1 is 0.2mm, preferably 7mm.

[0045] In this embodiment, the first receiving groove 2 and the second receiving groove 3 have a smaller depth and a smaller number of stamping times, thereby reducing production costs.

[0046] Moreover, the side wall of the second receiving groove 3 close to the first receiving groove 2 is inclined, so that the inclined side wall gradually approaches the first receiving groove 2 along the direction from the groove bottom of the second receiving groove 3 to the first shell 11 .

[0047] In this embodiment, the distance between the first receiving groove 2 and the second receiving groove 3 is X, the depth of the first receiving groove 2 is H, and 3H≥X≥0.5H. When the length of the first receiving groove 2 is the same as the length of the second receiving groove 3, that is, Figure 1 In the structure shown, the spacing X between the first receiving slot 2 and the second receiving slot 3 must be greater than H, preferably X = 1.5H. If X is less than H at this time, the stamping quality of the first receiving slot 2 and the second receiving slot 3 cannot be guaranteed, and the structural strength of the adjacent slot edges is weakened; when the length of the first receiving slot 2 is less than the length of the second receiving slot 3, the spacing X between the first receiving slot 2 and the second receiving slot 3 can be less than or equal to H. The smaller the length of the second receiving slot 3, the smaller the spacing X between the first receiving slot 2 and the second receiving slot 3. However, if X is less than 0.5H, the stamping quality of the first receiving slot 2 and the second receiving slot 3 is reduced, and the structural strength of the two slots cannot be guaranteed to meet the subsequent battery processing requirements. When the spacing X between the first receiving slot 2 and the second receiving slot 3 is too large, that is, when it exceeds 3H, the external overall size of the subsequent battery processing is too large, which is not conducive to the overall structural layout of the battery.

[0048] In other embodiments, the depth of the first receiving groove 2 may be equal to the depth of the second receiving groove 3 , as long as the volume of the first receiving groove 2 is greater than the volume of the second receiving groove 3 .

[0049] In this embodiment, the thickness of the substrate 1 is 0.1-0.4 mm. Optimally, the thickness of the substrate 1 is 0.2 mm. Compared with the thickness of the metal shell in the prior art, which is mostly 0.4-0.6 mm; the blade battery is 0.3 mm, the shell thickness in this embodiment has the advantages of ultra-thinness, light weight, low cost, and increased battery capacity per unit volume.

[0050] Second embodiment

[0051] Reference Figure 5 The battery of the second embodiment of the present invention includes an inner insulating film, an outer insulating film, a pole core, a positive electrode cover plate, a negative electrode cover plate and a metal shell of any of the above embodiments, the inner insulating film is respectively arranged on the opposite sides of the first shell 11 and the second shell 12, and the outer insulating film is arranged on the outer surfaces of the first shell 11 and the second shell 12.

[0052] The pole core is placed in the first receiving groove 2 , the positive electrode cover is installed in one of the first groove 4 and the second groove 5 , and the negative electrode cover is installed in the other of the first groove 4 and the second groove 5 .

[0053] The three edges of the metal shell except the edge where the first straight line is located are all welded and connected.

[0054] In the metal shell of this embodiment, the first cutting piece 81 and the second cutting piece 82 are cut off after the edges of the injection welding are completed.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A metal shell, It is characterized in that It comprises a first shell and a second shell respectively formed by folding a substrate along a first straight line; The first shell is in the shape of a flat plate; The second shell is provided with a first accommodating groove and a second accommodating groove arranged at intervals, and the first accommodating groove and the second accommodating groove are both recessed in a direction away from the first shell; One side surface of the first shell and one side surface of the second shell are arranged opposite to each other, and the outer edges of the first shell and the second shell are fixedly connected by welding and sealing, so that the first shell closes the first receiving groove and the second receiving groove, and the first receiving groove is used to receive the pole core; The volume of the first containing tank is greater than or equal to the volume of the second containing tank.

2. The metal housing according to claim 1, It is characterized in that The first accommodating groove is close to the first straight line, and the second accommodating groove is located on a side of the first accommodating groove away from the first straight line; The second housing is provided with a first groove and a second groove opening outward, the first groove is connected to the second receiving groove, and the second groove is connected to the second receiving groove; The first groove and the second groove are used to place the positive electrode cover plate assembly and the negative electrode cover plate assembly of the battery respectively.

3. The metal housing according to claim 2, It is characterized in that It also includes a first cutting piece and a second cutting piece, wherein the first cutting piece and the first shell are integrally formed, and the first cutting piece is arranged on a side of the first shell away from the first straight line; The second cutting piece and the second shell are integrally formed, and the second cutting piece is arranged on a side of the second shell away from the first straight line.

4. The metal housing according to claim 1, It is characterized in that The length of the first accommodating groove is the same as the length of the second accommodating groove.

5. The metal housing according to claim 4, It is characterized in that The ratio of the cross-sectional area of ​​the first receiving groove to the cross-sectional area of ​​the second receiving groove is 1:0.05 to 1:0.

5.

6. The metal housing according to claim 4, It is characterized in that The depth of the first accommodating groove is greater than or equal to the depth of the second accommodating groove.

7. The metal housing according to claim 5 or 6, It is characterized in that The depth of the first receiving groove is 5-40 mm; The depth of the second receiving groove is 2-20 mm.

8. The metal housing according to claim 1, It is characterized in that The distance between the first accommodating groove and the second accommodating groove is X, the depth of the first accommodating groove is H, and 3H≥X≥0.5H.

9. The metal housing according to claim 1, It is characterized in that The substrate has a thickness of 0.1-0.4 mm.

10. A battery, It is characterized in that The metal shell comprises the metal shell according to any one of claims 1 to 9.

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